Search is not available for this dataset
query
stringlengths 1
13.4k
| pos
stringlengths 1
61k
| neg
stringlengths 1
63.9k
| query_lang
stringclasses 147
values | __index_level_0__
int64 0
3.11M
|
|---|---|---|---|---|
Palladium‐Catalyzed C,N‐Cross Coupling Reactions of 3‐Halo‐2‐aminopyridines.
|
A variety of secondary and primary amines is applied in the reaction of the unprotected 3-bromo-2-aminopyridines using LiN(Tms)2 as a base and the appropriate Pd-catalyst (I).
|
Abstract An attempt was made to determine whether Cl-CCP and other known inhibitors and uncouplers of photophosphorylation act on high-energy states of chloroplasts. A theoretical analysis indicated that those uncouplers with a high affinity for high-energy states (Case 1a) could be experimentally distinguished from those which attack phosphorylation sites (Case 2) or have low affinities for the high-energy states (Case 1b) by regulating the rate of electron flow with electron transfer inhibitors such as DCMU. It was found that the uncouplers [Cl-CCP, gramicidin, and nigericin] have a high affinity for high-energy states. On the other hand, uncouplers such as arsenate, NH 4 Cl, quinacrine and chlorpromazine, and energy transfer inhibitors such as synthalin and phlorizin do not have a high affinity for high-energy states.
|
eng_Latn
| 31,300 |
Membrane Transport of Amphiphilic Compounds by Hepatocytes
|
Liver, being the central organ for degradation of compounds differing greatly in chemical and physical properties, must have the appropriate transport systems for vectorial membrane transport. Of outstanding interest are the transport systems for the great many of amphiphilic compounds, metabolites and xenobiotics, which are excreted hepatobiliarily, either unmetabolized or metabolized. In order to evaluate the number, the specificity, and the function of hepatic membrane transport systems for amphiphilic substances representative compounds of characteristic substance classes and their appropriate photolabile derivatives were used for: ::: ::: 1. ::: ::: Kinetic studies (K) ::: ::: ::: ::: ::: 2. ::: ::: Photoaffinity labelling (P) ::: ::: ::: ::: ::: 3. ::: ::: Differential photoaffinity labelling (D)
|
FIELD: chemistry. SUBSTANCE: invention concerns process of production of diisopropyl {[1-(hydroxymethyl)-cyclopropyl]oxy}methylphosphonate represented by the formula , which is the key intermediate compound in synthesis of antiviral nucleoside analogue. The invention also concerns new intermediate compounds of formulae and , and their production of compound (2) obtained under this invention, which is an antiviral nucleoside analogue (especially against hepatitis B virus) represented by the formula . EFFECT: high purity grade and high output. 4 ex
|
eng_Latn
| 31,301 |
Photoinduced triplet-triplet energy transfer in a 2-ureido-4(1H)-pyrimidinone-bridged, quadruply hydrogen-bonded ferrocene-fullerene assembly.
|
2-Ureido-4(1H)-pyrimidinone-bridged ferrocene-fullerene assembly I is designed and synthesized for elaborating the photoinduced electron-transfer processes in self-complementary quadruply hydrogen-bonded modules. Unexpectedly, steady-state and time-resolved spectroscopy reveal an inefficient electron-transfer process from the ferrocene to the singlet or triplet excited state of the fullerene, although the electron-transfer reactions are thermodynamically feasible. Instead, an effective intra-assembly triplet-triplet energy-transfer process is found to be operative in assembly I with a rate constant of 9.2×10(5) s(-1) and an efficiency of 73% in CH(2)Cl(2) at room temperature.
|
Abstract Intramolecular cycloaddition of N-alkenoyl β-enaminones occurs with high regioselectivity and diastereoselectivity leading to interesting synthons for the total synthesis of triquinanes or various sesquiterpenes.
|
eng_Latn
| 31,302 |
Molecular modeling, total synthesis, and biological evaluations of C9-deoxy bryostatin 1.
|
The bryostatins are a family of natural products of marine origin that display both intriguing structural complexity and a fascinating profile of biological activity.[1] These materials were isolated (from Bugula neritina) and their structures determined through the pioneering work of Pettit and coworkers.[2] Subsequently, a monumental large scale collection and isolation effort managed to yield some 18 grams of bryostatin 1, the most abundant and now most thoroughly investigated member of this family, from some 13,000 kg of the source organism.[3] This world’s supply of material has supported numerous biological investigations and roughly 80 clinical trials against various cancers.[4] Recently, a clinical trial against Alzheimer’s disease has also commenced.[5]
|
The easy cycloaddition of ureas with alkynyl alkoxy biscarbene complexes afforded, in fairly good yields, new biscarbene uracil analogs. X-ray structural data is reported for the dimethyluracil biscarbene complex. By changing the reaction conditions, a new non symmetric complex was obtained whose reaction with ethylenediamine afforded a new tetrakis amino carbene complex.
|
eng_Latn
| 31,303 |
Electroluminescence from Substituted Poly(thiophenes): From Blue to Near-Infrared
|
We report a systematic approach to the control of the conjugation length along the poly(thiophene) backbone. The planarity of the main chain can be permanently modified by altering the pattern of s ...
|
A fluorometric enzyme assay was developed to evaluate the ability of a variety of compounds to bind to and/or inhibit pyroglutamyl aminopeptidase I. Among these compounds were a series of chloromethyl ketone analogues of thyrotropin releasing hormone (TRH) which had previously been shown to possess TRH-like activity in the central nervous system and have now been found to be good inhibitors of pyroglutamyl aminopeptidase. Thus, it is suggested that the observed TRH-like CNS activity could derive indirectly from inhibition of endogenous TRH degradation by pyroglutamyl aminopeptidase I.
|
eng_Latn
| 31,304 |
Hepatoprotective Activity of Phyllanthus lawii against Carbon Tetrachloride-induced hepatic damage in rats.
|
The aerial parts of Phyllanthus lawii , family Euphorbiaceae was tested for hepatoprotective activity against CCl 4 in rats. The ethanol extract of Phyllanthus lawii has shown significant activity, lowering the serum enzymes like SGOT and SGPT in rats intoxicated with CCl 4 . Phyllanthus lawii also reversed the histopathological change induced by CCl4, there by justifying the folk use of the plant.
|
Platinum is a highly active and acid stable electrocatalyst for the hydrogen evolution reaction (HER). ::: Nonetheless, its high cost and scarcity limits its utility in clean energy systems on a large scale. Nanostructured ::: transition metal phosphides have recently emerged as Earth-abundant alternatives for the catalytic prodn. ::: of mol. hydrogen from acidic aq. solns. Phosphides of nickel, cobalt, iron, molybdenum, and tungsten have ::: been evaluated for the HER and found to require low overpotentials to produce H2 at operationally relevant ::: current densities for photoelectrochem. cells, while at the same time exhibiting high stability under strongly ::: acidic conditions. Furthermore, the microwire geometry allows the fabrication of photocathodes entirely ::: comprised of Earth-abundant materials that exhibit performance comparable to that of devices that contain Pt.
|
eng_Latn
| 31,305 |
A Fulvene Route to Group 4 Metallocene Complexes Bearing 4,7‐Bis(dimethylamino)‐Substituted Indenyl Ligands
|
N,N,N′,N′-Tetramethylsuccinamide (15) was selectively converted into the functionalized aminofulvene 16. Subsequent treatment with reagent 17, [ZrCl2(NMe2)2(L)2] (L = THF or 0.5 DME), resulted in the formation of the cyclization product 4,7-bis(dimethylamino)indene (21). Deprotonation with n-butyllithium, followed by the reaction of the resulting substituted indenyllithium reagent 22 with ZrCl4, gave the metallocene [4,7-bis(dimethylamino)indenyl]2ZrCl2 (23). The reaction of 22 with ZrCl3Cp furnished the complex [4,7-bis(dimethylamino)indenyl]CpZrCl2 (24). Fulvene 16, as well as the metallocene dichlorides 23 and 24, were characterized by X-ray diffraction. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
|
The degradation products of diclofenac in aqueous dosage form in accelerated storage conditions were characterized by electrospray ionization-ion trap mass spectrometry (ESI-MS). Liquid chromatography (LC)-MS analyses revealed the presence of three degradation products. ESI-MS(n) spectra were used to study diclofenac fragmentation in detail and to characterize the structures of degradation products. A previously described degradation product, formed by a cyclization reaction of diclofenac producing the indolinone derivative, was found. As any hydroxylated product was found, no oxidation seems to occur in the dosage form used. On the contrary, two degradates have been detected and identified, leading to a primary alcohol structure or an aldehyde function in place of the acetate group of diclofenac.
|
eng_Latn
| 31,306 |
Constructions of tetrahydro-γ-carboline skeletons via intramolecular oxidative carbon–carbon bond formation of enamines
|
The synthetically and biologically important 4-methyl and 4-methoxy tetrahydro-γ-carboline compounds were readily synthesized in high yields from an aryl amine and a 5-amino-3-oxopentanoate derivative through a series of reactions of enamination, oxidative annulation, deprotection/lactamization and the final reduction reaction of the carbonyl group. The underpinning strategy involves the oxidative C(sp2)–C(sp2) bond formation realized by either Pd(OAc)2/Cu(OAc)2 or a hypervalent iodine reagent.
|
Abstract : This report is intended as a guide for electro-optical applications engineers interested in the effects of polymolecular clusters of water upon infrared transmission of the atmosphere. It is a compendium of work on the subject ranging from the oldest to the newest, some of which is not yet generally accepted by the scientific community. A theoretical model for infrared absorption spectra due to intermolecular hydrogen bonding is developed from a simple cluster model. Expressions leading to approximate values of hydrogen-bond strength are developed, allowing equations and curves to be derived, from data in the literature, for equilibrium cluster concentrations in moist air or water vapor, as functions of saturation ratio and temperature. The very large differences in absorptivity between water in the vapor and liquid phases are explained, as are 'pressure-squared' and inverse temperature dependencies of water cluster absorption in the infrared. Applications are suggested. (Author)
|
eng_Latn
| 31,307 |
365 nm-Light-sensitive photobase generators derived from trans-o-coumaric acid
|
Abstract We have developed a novel photobase generator (PBG) that generates primary or secondary amines via a photocyclization reaction without gas generation by using trans-o-coumaric acid as the molecular skeleton. To expand the absorption band to the long wavelength region, a chemical modification was performed to the PBG in which a nitro group was introduced to its aromatic ring. It was confirmed that the PBG absorbs 365 nm-light to change its chemical state in a methanol solution by UV–vis spectral measurements. Anionic UV curing of poly(glycidyl methacrylate) films with 365 nm-light irradiation was accomplished by using the PBG instead of the prototype generator.
|
Abstract : The objectives of this report are 1. Production of an antiserum against melanopsin, a putative circadian photoreceptor, permitting analysis of its expression pattern in mammalian retina. 2. Heterologous expression of melanopsin using recombinant baculovirus for a first characterization of its biochemical properties.
|
eng_Latn
| 31,308 |
Phthalimide–thiophene-based conjugated organic small molecules with high electron mobility
|
A series of low-cost phthalimide end-capped oligothiophene small molecules with variations to the terminal alkyl chain and number of thiophene units in the conjugated core have been synthesized and investigated. All molecules exhibit H-aggregation in the solid-state but different crystal structures and electronic properties, showing that subtle chemical modifications can result in dramatic changes to molecular self-assembly. Field-effect transistors display high electron mobilities of up to 0.2 cm2 V−1 s−1.
|
Abstract Exposure of the dorsal skin of hairless mice to the light of a germicidal lamp under standardized conditions produces reproducible, time-dependent increases of putrescine and spermidine concentrations, and a decrease of spermine levels, concomitant with the increase of the rate of DNa synthesis. Systemic or topical treatment of the animals with α-difluoromethylornithine, an enzyme-activated irreversible inhibitor of ornithine decarboxylase, completely prevents the uv light-induced rapid formation of putrescine, and diminishes the enhancement of polyamine turnover rates. A significant effect of the drug on the rate of DNA synthesis could not be shown. The model is suitable for the study of interrelations between polyamine metabolism and cell proliferation and for the screening of compounds designed as inhibitors of polyamine biosynthesis.
|
eng_Latn
| 31,309 |
Study of Phase Transfer Catalysis by Layered Scintillation Method
|
The static and kinetic feature of the reaction of sodium cyanide with 1-bromoalkanes in the presence of various phase transfer catalysts was investigated in the oil/water system by using a layered scintillation method and the mechanism of catalytic action was discussed. From the measurement of equilibrium constants for both reactions of hexadecyltrimethylammonium cyanide with 1-bromooctane and of sodium cyanide with hexadecyltrimethylammonium bromide in organic phase, it was pointed out that the latter reaction was responsible for the advance of overall reaction. It was also found that majority of the phase transfer catalysts exist in the oil phase. It was suggested that an uptake reaction of cyanide ion from the aqueous phase at the interface is essential and that the reaction process does not follow a simple model proposed by Starks et al.
|
The noise properties of two multi-heterodyne spectrometers based on multi-mode semiconductor lasers (QCLs and ICLs) are investigated to determine their detection performance limitations. Both laser technologies provide well-defined multi-heterodyne beat-note structures suitable for spectroscopic measurements.
|
eng_Latn
| 31,310 |
A portable liquid crystal-based polarized light system for the detection of organophosphorus nerve gas.
|
Liquid crystal (LC)-based sensors have the advantageous properties of being fast, sensitive, and label-free, the results of which can be accessed directly only through the naked eye. However, the inherent disadvantages possessed by LC sensors, such as relying heavily on polarizing microscopes and the difficulty to quantify, have limited the possibility of field applications. Herein, we have addressed these issues by constructing a portable polarized detection system with constant temperature control. This system is mainly composed of four parts: the LC cell, the optics unit, the automatic temperature control unit, and the image processing unit. The LC cell was based on the ordering transitions of LCs in the presence of analytes. The optics unit based on the imaging principle of LCs was designed to substitute the polarizing microscope for the real-time observation. The image processing unit is expected to quantify the concentration of analytes. The results have shown that the presented system can detect di...
|
Photocatalytic oxidation has broad application prospects in water pollution control due to its efficient removal of trace refractory organics without secondary pollution.The types and characteristics of emerging organic contaminants were described.The reaction mechanism of photocatalytic oxidation was analyzed.The treatment effect and research progress of various endocrine disrupting compounds and pharmaceuticals and personal care products by photocatalytic oxidation were illustrated in detail.Moreover,the problems and the tendency of future prospective technology development were also discussed.
|
eng_Latn
| 31,311 |
Antiviral activity of the interferon α family: Biological and pharmacological aspects of the treatment of chronic hepatitis C
|
Introduction: Type I interferons (IFNs) comprise a group of at least 13 structurally related subtypes of IFN-α with similar, but not identical, biological activities. Each subtype displays a unique activity profile; only IFN-α2a and IFN-α2b subtypes together with natural IFN-α preparations are currently used in the clinical practice, so that the remaining IFN-α subtypes are a still unexploited reservoir of opportunity also in the new era of direct-acting antiviral agents for the treatment of hepatitis C virus (HCV). Areas covered: This paper reviews recent progress in the study of the biology of IFN family, the antiviral action mechanism and the strategies employed by HCV to evade IFN action. Currently available IFN preparations for the treatment of chronic hepatitis C infection are described and what is currently known on the pharmacokinetics, pharmacodynamics and immunogenicity of IFN-α preparations used in clinical practice are summarized. Expert opinion: The characterization of multifunctional nature ...
|
Abstract A wavelet-based technique for numerical integration of species-conservation equations describing atmospheric pollutant transport and fate is described. This technique applies hexuplet families of spline-based biorthogonal wavelets using a quasi-Galerkin approach. The wavelet families described here are advantageous because, in addition to their biorthogonal character, they satisfy special relationships enabling straightforward evaluation of function derivatives. Moreover, the compact nature of the wavelets suggests the possibility of performing chemistry calculations efficiently in the wavelet-transform domain. The present article describes the selected wavelet families, their derivative relationships, and the proposed methods for their numerical application. In addition, it presents some simple numerical-integration tests to demonstrate the method and examines the method’s potential for performing chemistry calculations in the wavelet domain. More extensive application of the wavelet-based metho...
|
eng_Latn
| 31,312 |
Synthesis and properties of substituted thorocenes
|
Disubstituted bis(cyclooctatetraene)thorium(I) (thorocene) complexes have been prepared. Unlike thorocene itself, these derivatives are soluble in organic solvents. Proton and /sup 13/C NMR spectra of these air-sensitive diamagnetic compounds show a significant decrease in electron density in the rings relative to dipotassium cyclooctatetraene salts. The chemistry of thorocenes and uranocenes is compared. Like uranocenes, thorocenes do not undergo facile ligand-exchange reactions with cyclooctatetraenes; both, however, do give rapid exchange with cyclooctatetraene dianions.
|
This thesis presents computational chemistry studies of keto-enol reactions and chromophores of photobiological signicance.The rst part of the thesis is concerned with two protein-bound chromophore ...
|
eng_Latn
| 31,313 |
Determination of Chromophore Structure and Photochemistry in Bacteriorhodopsin with Resonance Raman, NMR, and Chemical Analogues
|
Bacteriorhodopsin (BR) is an intrinsic membrane protein that transduces light-energy into a trans-membrane protonmotive force. To elucidate the mechanism of this important process, it is necessary to determine the structure of the retinal chromophore in BR and its intermediates and to characterize important chromophore-protein interactions. This paper will review recent physical chemical and bio-organic approaches that we have developed to study chromophore structure and environment in bacteriorhodopsin. A model for the molecular mechanism of proton-pumping based on inversion of the unprotonated Schiff base nitrogen is presented.
|
The title polymers have been prepared by nucleophilic substitution of 2,3-dimethyl- and trimethylhydroquinone, and 3,3′-dimethyl- and 3,3′,5,5′-tetramethylbiphenol with difluorobenzophenone. These polymers have been brominated to various degrees of substitution. The dimethyl PEEK can only be monobrominated; trimethyl PEEK yields mono- and dibromomethyl functional groups in the ratio 2:1. These results can be explained by steric hindrance to dibromination of the vicinal methyl groups. Dimethyl- and tetramethylbiphenyl PEEK can be dibrominated completely.
|
eng_Latn
| 31,314 |
Development of Caco-2 Cells Expressing High Levels of cDNA-Derived Cytochrome P4503A4
|
Purpose. To develop Caco-2 cell derivatives expressing high levels of human cytochrome P450 drug metabolizing enzymes.
|
This work deals with the analysis of the performance and emissions of ethanol HCCI/PSCCI engines by means of a Dynamic Adaptive Chemistry (DAC) technique. The implementation of such a technique provides a reduction of the computational cost of the simulations without compromising the reliability of the results. Very accurate results, in terms of pressure and heat release rate profiles and CO, CO2 and UHC emissions, are obtained with ethanol as the only species for the DRGEP graph search both with the charge uniformly distributed in the combustion chamber and by directly injecting liquid fuel in the same chamber. The global speed up of DAC simulations is twice with respect to a full mechanism which consists of 57 species and 288 reactions and a further increase is expected when DAC is compared to very detailed kinetics.Copyright © 2012 by ASME
|
eng_Latn
| 31,315 |
Two succinic semialdehyde dehydrogenases are induced when Escherichia coli K-12 Is grown on gamma-aminobutyrate.
|
Abstract ::: When Escherichia coli K-12 was grown on gamma-aminobutyrate, a second succinic semialdehyde dehydrogenase, dependent upon oxidized nicotinamide adenine dinucleotide or oxidized nicotinamide adenine dinucleotide phosphate and distinct from that induced by gamma-aminobutyrate, was gratuitously induced by succinic semialdehyde.
|
Abstract Several novel applications of Deep Eutectic Solvents (DESs) have emerged recently. With a growing interest in the field, there is an urge to understand formation and functioning of these solvents at molecular level, which in turn would assist in further designing of DESs. We herein performed molecular dynamics simulations on three of the commonly used type III DES, viz, reline, ethaline, and glyceline, which are mixtures of urea, ethylene glycol, and glycerol with choline chloride at eutectic composition. Our results explain the role of inter-molecular and intra-molecular hydrogen bonding and energies on formation of these DESs. Furthermore, the ability of these DESs to be altered in a desired way through a simple addition of water makes it versatile solution for several other applications. Hence, simulations are also performed on the aqueous DES solutions, which reveal the effect of water on intermolecular network of interaction existing within these DESs.
|
eng_Latn
| 31,316 |
Synthesis of 4,6-Dimethoxyindoles
|
Syntheses are described for nine new 4,6-dimethoxyindoles, incorporating phenyl, pyridin-2-yl, methoxycarbonyl , carboxy and methyl groups in the 2- and/or 3-positions.
|
A simple, inexpensive approach is proposed for enhancing the durability of automotive proton exchange membrane fuel cells by selective promotion of the hydrogen oxidation reaction (HOR) and suppression of the oxygen reduction reaction (ORR) at the anode in startup/shutdown events. Dodecanethiol forms a self-assembled monolayer (SAM) on the surface of Pt particles, thus decreasing the number of Pt ensemble sites. Interestingly, by controlling the dodecanethiol concentration during SAM formation, the number of ensemble sites can be precisely optimized such that it is sufficient for the HOR but insufficient for the ORR. Thus, a Pt surface with an SAM of dodecanethiol clearly effects HOR-selective electrocatalysis. Clear HOR selectivity is demonstrated in unit cell tests with the actual membrane electrode assembly, as well as in an electrochemical three-electrode setup with a thin-film rotating disk electrode configuration.
|
eng_Latn
| 31,317 |
The effect of catecholamines on H+ and NH+4 excretion in toad urinary bladder.
|
The catecholamines epinephrine and norepinephrine, when placed on the toad urinary bladder in vitro, at a final concentration of 50 microM, caused a significant increase in H+ and NH+4 excretion by the bladder. Isoprenaline in a final concentration of 50 microM also increased H+ and NH+4 excretion in the bladder. Propranolol at a concentration of 50 microM blocked the stimulation of H+ excretion by isoprenaline but propranolol at 100 microM was required to block the stimulation of NH+4 by isoprenaline. The dose-response analysis indicates that the concentration of epinephrine used (50 microM) is at or near the maximal effective dose. These findings indicate that catecholamines stimulate H+ and NH+4 excretion in the toad urinary bladder and evidence suggests this may be mediated via the beta receptor mechanism.
|
Abstract This review deals with the reaction mechanisms of polyaminecarboxylate complexes of different transition metals such as Fe, Mn, Ni, and Ru. Three types of chemical processes are treated, viz. water-exchange reactions, the binding of NO, and the activation of peroxides. In each case, the nature of the polyaminecarboxylate chelate and its influence on the underlying reaction mechanism are considered. In general, the complexes are either six- or seven-coordinate and all contain a coordinated water molecule. The lability of the latter is controlled by the nature of the polyaminecarboxylate chelate and the oxidation state of the metal ion. The binding of NO and the activation of peroxide are in turn controlled by the lability of the coordinated water molecule that is displaced during the interaction with these small molecules.
|
eng_Latn
| 31,318 |
Sitting above the maze: recent model discoveries in molecular science
|
The 2013 Nobel Prize in Chemistry has convinced the world that how important the role that computational sciences play in chemical and materials sciences. In this review, computational methods and rational molecule design, including quantum mechanics and molecular mechanics methods, have been applied to study electronic structures and the interactions in a number of important applications at molecular level. The applications which include bioactive compounds, drug candidates and photoactive molecules at Swinburne University in the past several years are discussed. The research is in close collaboration with world class experimental groups from spectroscopy, organic and medicinal synthesis laboratories and most recently to γ-ray spectroscopy as well as other theory groups in the world. Ionisation spectra of biomolecules and bioactive compounds including amino acids, DNA bases, cyclic dipeptides, drug candidates, complexes and photoactive molecules are discussed. Most recent projects such as infrared spectr...
|
In this research manuscript, the author has presented a novel notion of Higher Order Prime Numbers.
|
eng_Latn
| 31,319 |
Perfluoroaryl-substituted cyclopentadienyl complexes of transition metals
|
A review with 172 references. Cyclopentadienyl (Cp) and its substituted congeners are among the most common ligands in organometallic chemistry. Ring substituents attached to Cp can influence the structure, physico-chemical properties, and reactivity of coordinated metal fragments. This article describes the synthesis of perfluoroaryl-substituted cyclopentadienes and indenes and their use as transition metal ligands. Emphasis is placed on trends in spectroscopic and electrochemical behavior, structure, and reactivity that arise from the highly electron-withdrawing character of the perfluoroaryl substituents.
|
A ring-expanded bryostatin analogue was synthesized by utilizing a Ru-catalyzed tandem tetrahydropyran formation, a Pd-catalyzed tandem dihydropyran formation, and a ring-closing metathesis (RCM) as key steps. The analogue possesses potent antitumor activity against the NCI-ADR cancer cell line with an IC50 of 123 nM.
|
eng_Latn
| 31,320 |
Synthesis and characterization of iodoazidobenzylpindolol
|
A high affinity β-adrenergic ligand, iodoazidobenzylpindolol, was synthesized and characterized. The absorption spectrum of this compound changed markedly upon photolysis, consistent with decomposition of the azide group. This compound has a Ko of 5-7 X 10- 10 M for the duck erythrocyte ghost β-3-adrenergic receptor when measured in a competitive binding assay.
|
Abstract 5,8-Dimethoxyquinolin-4-one has been transformed in five steps into a 7-oxo-1,6-diazaphenalene and in 4 steps into 6-aza-1-oxaphenalene.
|
eng_Latn
| 31,321 |
QSAR studies on formal potentials of phenol derivatives
|
The molecular structural parameters of phenol derivatives were calculated by AM1 semi - empirical molecular orbital method of quantum chemistry. The relationship between the formal potential and the molecular structural parameters were analyzed by multiply linear regression methods. The formal potentials of phenol derivatives show a good relation with bond length of C-O,L(C, -O7) , ion-ization potential,Ip, the net charge of C3 ,e( C3) , and the dipole in Z direction, Dz ,with the regression equation of E° = -25. 267 + 17.00 L(C1 -O7) +0.293 Ip+1.415 e(C3) +0.9825 Dz(R =0. 897,SD) =0. 057)。 The reasonable formal potentials of 11 phenol derivatives are predicted, and some regularity of the effects of different groups and different substitution positions on the electrochemical activity of phenol derivatives are discussed.
|
NPRP grant [09 - 1001 - 2 - 391] from the Qatar National Research Fund (a member of Qatar Foundation).
|
eng_Latn
| 31,322 |
Hepta-1,6-diene and diallyl ether complexes of palladium(0) and platinum(0):a route to L–M(alkene)2 complexes containing non-activated alkenes
|
With hepta-1,6-diene and diallyl ether, Pd0 and Pt0 form highly reactive homoleptic dinuclear M2(1,6-diene)3 complexes, which are cleaved by donors L (e.g. C2H4, phos-phanes, phosphites, isonitriles) to afford mononuclear derivatives L–M(1,6-diene); the X-ray structure of (Me3P)Pd{(η2-CH2CHCH2)2O} has been determined.
|
Diethylpyrocarbonate treatment of the neutral endopeptidase (EC 3.4.24.11) inhibits both catalytic activity and binding of the inhibitor [3H]-N(R,S)-3-hydroxyaminocarbonyl-2-benzyl-1-oxopropyl]-glycine. The loss of activity can be reversed by hydroxylamine and almost completely prevented by the competitive inhibitor phenylalanyl-leucine suggesting the presence, as in thermolysin, of a histidine residue at the active site. Butanedione treatment also reduces both catalytic activity and [3H] inhibitor binding. Phenylalanyl-leucine completely protects from the butanedione induced loss of activity, providing further evidence for an essential arginine at the active site. In contrast, the tyrosine modifying agent N-acetylimidazole has no apparent effect on enzyme activity.
|
eng_Latn
| 31,323 |
Photochemistry and C-H Bond Activation Reactivity of (HBPz*3)Rh(CO)2 (Pz* = 3,5-Dimethylpyrazolyl) in Hydrocarbon Solution
|
Two electronically excited states with very different reactivities are implicated in the photochemistry of the highly effective C-H bond activating (HBPz*{sub 3})Rh(CO){sub 2} complex in room-temperature n-pentane solution. Unusually, the lower energy level is relatively prominent and an {eta}{sup 3} {yields} {eta}{sup 2} ligand dechelation mechanism is invoked, analogous to the thermal process in this complex. In contrast, the upper energy excited state gives rise to extremely efficient C-H bond activation ({phi}{sub CH} = 0.34 at 313 nm) and this suggests that CO dissociation is the initial step in the oxidative addition mechanism.
|
Aryl groups bound to the meso positions of porphyrins often react with neighboring groups, in particular s-acyl groups to give highly diversified monomeric and dimeric new functionalized porphyrins. The products, whose meso-aryl ring approaches coplanarity with the porphyrin macrocycle, show large shifts of UV-visible absorption bands and various potentialities for building external chelating moieties and assembling oligoporphyrins.
|
eng_Latn
| 31,324 |
Of humans and hamsters: comparative analysis of lipid peroxidation, glutathione, and glutathione-dependent enzymes during oral carcinogenesis
|
We examined the extent of lipid peroxidation and the amount of reduced glutathione (GSH), and activities of the GSH-dependent enzymes, glutathione peroxidase (GPx) and glutathione S-transferase (GST), in human oral tumour tissue and 7,12-dimethylbenz[a]anthracene-(DMBA)-induced hamster buccal pouch tumour tissues. Diminished lipid peroxidation in the oral and hamster tumours was accompanied by a significant reduction in the concentration of phospholipids and an increase in the cholesterol:phospholipid ratio. The concentration of glutathione and the activities of GPx and GST were raised in both human oral and hamster tumour tissues. Our results show that the patterns of changes in human oral squamous cell carcinomas and chemically-induced carcinomas of the hamster buccal pouch are similar.
|
So far, the strategies for the synthesis of biomimetic dental enamel-like hydroxyapatite [Ca10(PO4)6(OH)2, HAp] have attracted great interest due to the extremely high orientation of HAp crystals. In the present study, a facile method via hydrothermal treatment of the hillebrandite [Ca2(SiO3)(OH)2] nanobelts as hard-templates in trisodium phosphate aqueous solutions was developed to synthesize the dental enamel-like HAp nanorod arrays, in the absence of any proteins, surfactants, organic solvents or organic molecule directing reagents. The morphology observations demonstrated that the highly oriented HAp arrays were constructed of uniform nanorods parallel to each other along the c-axis. A possible hard-template transformation mechanism based on the crystal structure and morphology of the hillebrandite nanobelts was proposed.
|
eng_Latn
| 31,325 |
Pharmaceutical composition for preventing and treating diabetic nephropathy including adenosine derivative
|
Provided is a pharmaceutical composition for preventing or treating diabetic nephropathy. According to the present invention, a pharmaceutical composition for preventing or treating diabetic nephropathy includes an adenosine derivative compound or a pharmaceutically acceptable salt thereof as an active ingredient.
|
1. ::: ::: On the basis of obtained kinetic and thermodynamic parameters of the reaction of the reversible recombination of the 2-(4′-dimethylaminophenyl)indan-1,3-dionyl radical, it is established that the most dominating influence on the rate of this reaction is nonspecific solvation. ::: ::: ::: ::: ::: 2. ::: ::: Values of rate constants of the recombination of the 2-(4′-diphenylaminophenyl)indan-1,3-dionyl radical has a V-shaped dependence on the parameter ET, Strong solvation of this radical in chloroform converts the recombination reaction from a diffusion-controlled range to a kinetic range.
|
eng_Latn
| 31,326 |
Light and electron microscopic in situ hybridization: non-radioactive labeling and detection, double hybridization, and combined hybridization-immunocytochemistry.
|
We performed light and electron microscopic in situ hybridization, according to the same protocol and without pretreatment of sections, on Lowicryl- and LR Gold-embedded cells. Digoxigenin (DIG)- or biotin-labeled riboprobes were visualized by direct or indirect immunodetection using commercially available gold-antibody conjugates with 0.8-10-nm gold grains. At the ultrastructural level, the main findings were that DIG-labeled probes gave a slightly higher labeling intensity (grains per signal) than biotin. The direct detection method produced a more compact signal, which led to better resolution at medium and high magnifications. Labeling intensities of all gold grain sizes were essentially equal. Grain sizes of 5 nm and larger were highly preferable because available enhancement methods are unsatisfactory for ultrasmall grains. The optimized immunodetection protocols are suitable for double hybridization with two different probes and for combined hybridization and immunocytochemistry.
|
The course of the photochemical reactions involved in the photolysis of O-methylcytosine is strongly affected by the presence of various anions. Similar anionic effects were noted during the photolysis of cytosine but the products of this reaction appeared to be less suitable for further investigation. Ultraviolet irradiation of O-methylcytosine in water leads to destruction of the characteristic absorption bands, while irradiation in phosphate leads to the production of a new compound with marked absorption at 300 mμ, and irradiation in pyrophosphate, glycero-phosphate, citrate, or cacodylate leads to the production of compounds with marked absorption at 274 mμ. The phosphate-dependent photolysis of O-methylcytosine has been studied in some detail and the product has been isolated and purified. Apparently the H2PO4− ion acts as a catalyst in a reaction which involves the loss of 1 mole of ammonia and the addition of 2 moles of water to O-methylcytosine.
|
eng_Latn
| 31,327 |
Spectral modification of shock accelerated ions using hydrodynamically shaped gas target
|
We report on reproducible shock acceleration from irradiation of a λ=10 μm CO_{2} laser on optically shaped H_{2} and He gas targets. A low energy laser prepulse (I≲10^{14} W cm^{-2}) is used to drive a blast wave inside the gas target, creating a steepened, variable density gradient. This is followed, after 25 ns, by a high intensity laser pulse (I>10^{16} W cm^{-2}) that produces an electrostatic collisionless shock. Upstream ions are accelerated for a narrow range of prepulse energies. For long density gradients (≳40 μm), broadband beams of He^{+} and H^{+} are routinely produced, while for shorter gradients (≲20 μm), quasimonoenergetic acceleration of protons is observed. These measurements indicate that the properties of the accelerating shock and the resultant ion energy distribution, in particular the production of narrow energy spread beams, is highly dependent on the plasma density profile. These findings are corroborated by 2D particle-in-cell simulations.
|
ConspectusThe axioms of stereoelectronic theory constitute an atlas to navigate the contours of molecular space. All too rarely lauded, the advent and development of stereoelectronic theory has been one of organic chemistry’s greatest triumphs. Inevitably, however, in the absence of a comprehensive treatise, many of the field’s pioneers do not receive the veneration that they merit. Rather their legacies are the stereoelectronic pillars that persist in teaching and research. This ubiquity continues to afford practitioners of organic chemistry with an abundance of opportunities for creative endeavor in reaction design, in conceiving novel activation modes, in preorganizing intermediates, or in stabilizing productive transition states and products. Antipodal to steric governance, which mitigates destabilizing nonbonding interactions, stereoelectronic control allows well-defined, often complementary, conformations to be populated. Indeed, the prevalence of stabilizing hyperconjugative interactions in biosynt...
|
eng_Latn
| 31,328 |
Progress of catalytic wet air oxidation technology
|
Abstract Catalytic wet air oxidation (CWAO) is one of the most economical and environmental-friendly advanced oxidation process for high strength, toxic, hazardous and non-biodegradable contaminants under milder conditions, which is developed on the basic of wet air oxidation. Various heterogeneous catalysts including noble metals and metal oxides have been extensively studied to enhance the efficiency of CWAO. The advances in the research on wastewater treatment by CWAO process are summarized in aspects of reaction mechanism investigation, reaction kinetics study and catalyst development. It is pointed out that the preparation of active and stable catalysts, the investigation on reaction mechanisms and the study on reaction kinetics models are very important for the promotion of CWAO application.
|
The lifespan of Caenorhabditis elegans can be extended by the administration of synthetic superoxide dismutase/ catalase mimetics (SCMs) without any effects on development or fertility. Here we demonstrate that the mimetics, Euk-134 and Euk-8, confer resistance to the oxidative stress-inducing agent, paraquat and to thermal stress. The protective effects of the compounds are apparent with treatments either during development or during adulthood and are independent of an insulin/IGF-I-like signalling pathway also known to affect thermal and oxidative stress resistance. Worms exposed to the compounds do not induce a cellular stress response and no detrimental effects are observed.
|
eng_Latn
| 31,329 |
Detection of Oxidation of L-Cysteine by Dimethyl Sulfoxide in Aqueous Solutions by IR Spectroscopy
|
We have used IR spectroscopy to study the reaction between L-cysteine and dimethyl sulfoxide in aqueous medium. We have found that reaction occurs with formation of an insoluble product, which we have identified. We show that oxidation of L-cysteine by dimethyl sulfoxide can occur at an appreciable rate under mild conditions, with formation of L-cystine, dimethyl sulfide, and water.
|
Abstract The temperature-spectral dependencies of refractive indices ni and birefringence Δni of first time synthesized RbNH4SO4 crystals in wide temperature (77–300 K) and spectral (250–850 nm) regions were measured. It was shown that ni dispersion is normal and very fine described by Zelmeer's formula. It was found that Δny = 0 for λ = 633 nm at T=189 K and the isotropic point have a nearly “isospectral” character. The isotropic point is displacing to longwave region at temperature decrease. The second-order phase transition at T = 120 K was observed.
|
eng_Latn
| 31,330 |
The reactivity of the bis(phenylethynyl)aurate(I) complex anion. Synthesis and characterization of novel di- and tri-nuclear group IB metal arylacetylides
|
Abstract The syntheses of the novel complexes ((PPh 3 ) 2 N)(PhC 2 AuC 2 Ph)(MC 2 R) (I: M = Au, R = Ph; II: M = Ag, R = p -MeC 6 H 4 )and ((PPh 3 ) 2 N)(PhC 2 AuC 2 Ph)(AuC 2 Ph)(CuC 2 - p -MeC 6 H 4 ) (III) are described and structures considered.
|
In this paper, we demonstrated that Au nanorods coated with a shell composed of Pt nanodots (Au@Pt nanostructures) exhibited intrinsic oxidase-like, peroxidase-like and catalase-like activity, catalyzing oxygen and hydrogen peroxide reduction and the dismutation decomposition of hydrogen peroxide to produce oxygen. Based on these findings, we established an Au@Pt nanostructures based enzyme linked immunosorbent assay (ELISA) for the detection of mouse interleukin 2 (IL-2). In comparison with natural enzymes, Au@Pt nanostructures have advantages of low cost, easy preparation, better stability, and tunable catalytic activity (compared with HRP), which make them a promising enzyme mimetic candidate and may find potential applications in biocatalysis, bioassays, and nano-biomedicine such as reactive oxygen species (ROS)-related fields (anti-aging and therapeutics for neurodegenerative diseases and cancers).
|
eng_Latn
| 31,331 |
Synthetic Utility of Some Substituted Quinolinones
|
This book is concerened with studying the oxidation of 3-acetyl-4-hydroxyquinolin-2(1H)-one via selenium dioxide. The first chapter was introduced the synthesis and chemical reactivity of acetylquinolinone. Then, the second chapter is divided to Study the oxidation reaction and show the chemical reactivity of α- keto acid with different reagents. The third chapter is showed the thermal Study for α-keto acid and ester followed by in fourth chapter; the biological activity for different compound. Afterwards, in five chapter, there were chemistry and biochemistry experimental. Finally conclusion about this book and references.
|
In this, the first of two Letters, we describe how a P3/P4 urea linking unit was used to greatly enhance the biochemical and replicon potency of inhibitors based upon the pyrrolidine-5,5-trans-lactam template. Compound 7b demonstrated a 100 nM IC50 in the replicon cell-based surrogate HCV assay.
|
eng_Latn
| 31,332 |
Potent and selective 5-LO inhibitor bearing benzothiophene pharmacophore: Discovery of MK-5286
|
The strategy and SAR studies that led to the discovery of a novel potent and orally available 5-lipoxygenase (5-LO) inhibitor 3-(4-fluorophenyl)-6-({4-[(1S)-1-hydroxy-1-(trifluoromethyl)propyl]-1H-1,2,3-triazol-1-yl}methyl)-1-benzothiophene-2-carboxamide ((S)-2l or MK-5286) were described.
|
1. ::: ::: On the basis of obtained kinetic and thermodynamic parameters of the reaction of the reversible recombination of the 2-(4′-dimethylaminophenyl)indan-1,3-dionyl radical, it is established that the most dominating influence on the rate of this reaction is nonspecific solvation. ::: ::: ::: ::: ::: 2. ::: ::: Values of rate constants of the recombination of the 2-(4′-diphenylaminophenyl)indan-1,3-dionyl radical has a V-shaped dependence on the parameter ET, Strong solvation of this radical in chloroform converts the recombination reaction from a diffusion-controlled range to a kinetic range.
|
eng_Latn
| 31,333 |
IN VITRO METABOLISM STUDY OF 3′-OH-2,4-diBDE-7 IN RAT LIVER S9 FRACTION
|
Polybrominated diphenyl ethers(PBDEs) are an important class of brominated flame retardants that have been widely used in industrial and consumer products.PBDEs have become worldwide environmental pollutants because of the bioaccumulation,long-distance transportation and potential biological toxicities.Hydroxylated polybrominated diphenyl ethers(OH-PBDEs) are a relatively new group of phenolic compounds that have attracted particular interest due to their endocrine disrupting potency.OH-PBDEs are similar to PBDEs in chemical structure,but were reported to show stronger biological effects.In this study,we investigated in vitro metabolic behaviors of selected 3′-OH-BDE-7 in rat liver S9 fraction.The obtained results indicated that 2,4-dibromophenol and diOH-PBDEs were the major metabolites of OH-PBDEs.It′s worth noting that the hydroquinone like metabolites might pose a potential health risk to human and wild animals.
|
New ruthenium(III) complexes of the type [RuX2en2] A(en = ethylenediamine, X2= C2O4, Cl H2O, Cl l, Cl2, Br2, or l2; A = Cl, Br, l, ClO4, or p-Me·C6H4·SO2·O) have been isolated, together with complexes of the related ligands triethylenetramine and optically active propylenediamine. Magnetic susceptibilities show that all the compounds have the spin-paired d5 configuration. The cation [RuCl2en2]+ has been resolved into its optical enantiomorphs, and its structure related to that of other bis(ethylenediamine)ruthenium(III) compounds, all of which are assigned a cis configuration. Ultraviolet, visible, and infrared spectra are reported, and the use of infrared spectra in the detection of geometrical isomerism is discussed. New mono-ethylenediamine complexes [RuX4en]– have been isolated in combination with the cations [RuX2en2]+ and (phen H)+(phen = 1,10-phenanthroline; X = Cl, Br, l, or ½C2O4).
|
yue_Hant
| 31,334 |
Spectroscopic and Structural Studies of Cyanine Dyes in Functionalized Langmuir–Blodgett Films: Electron and Energy Transfer Processes
|
Formation of the J-aggregates with redshifted bands and the H-aggregates with blue-shifted bands for a long-chain merocyanine (MC) could be controlled by mixing the molecular matrix components in the monolayer assembly. The binary Langmuir–Blodgett (LB) film containing MC and Cd arachidate (AA) provided the J-aggregates which have a sharp fluorescence with less Stokes shift. The ternary LB system having MC–AA and octadecane (OD) showed the H-aggregates in addition to the J-aggregates. The structures of the J- and H-aggregates were studied by atomic force microscopy and X-ray diffraction analysis. Additionally, the photo-induced electron transfer from the MC J-aggregate donor to a long-chain bipyridilium and the energy transfer from another cyanine dye donor to the MC H-aggregate acceptor were investigated in the hetero-LB films by varying the separation between the donor and acceptor layers.
|
Abstract A wavelet-based technique for numerical integration of species-conservation equations describing atmospheric pollutant transport and fate is described. This technique applies hexuplet families of spline-based biorthogonal wavelets using a quasi-Galerkin approach. The wavelet families described here are advantageous because, in addition to their biorthogonal character, they satisfy special relationships enabling straightforward evaluation of function derivatives. Moreover, the compact nature of the wavelets suggests the possibility of performing chemistry calculations efficiently in the wavelet-transform domain. The present article describes the selected wavelet families, their derivative relationships, and the proposed methods for their numerical application. In addition, it presents some simple numerical-integration tests to demonstrate the method and examines the method’s potential for performing chemistry calculations in the wavelet domain. More extensive application of the wavelet-based metho...
|
eng_Latn
| 31,335 |
Synthesis and reactivity of iron acyl complexes modeling the active site of [Fe]-hydrogenase.
|
A [Fe(II)Fe(II)] dithiolate complex containing acyl and carbonyl ligands was synthesized. The diiron complex reacted with phosphine, cyanide, isocyanide, and CO to give monomeric Fe(II) complexes reproducing the first coordination sphere of the active site of [Fe]-hydrogenase (H(2)-forming methylene-tetrahydromethanopterin dehydrogenase, Hmd) in various states. All the acyl and carbonyl carbons in the diiron complex underwent facile isotopic exchange with (13)CO via monomeric Fe tricarbonyl intermediates.
|
Abstract Photosensitivity based practical applications of chalcogenide glasses such as high resolution inorganic photoresists require thorough understanding of the relations between the glass structure and the etching kinetics. In this paper we report on the selective wet etching of thermally evaporated As2Se3 thin films carried out using amine based solutions. The relation between photo- and thermo-induced structural changes in thin As2Se3 films and the decrease of the etching rate, increase of the etching process' activation energy respectively, was determined.
|
eng_Latn
| 31,336 |
Vibrational study of crystal phase transitions in pyrrole (C4H5N) and C4D5N
|
Infrared and Raman spectra of crystalline pyrrole and pyrrole-d5 were recorded in the range 5–4000 cm−1. The behaviour of internal and external modes was studied as a function of temperature between 200 and 5 K. Two phase transitions were observed at 67 and 30 K and their mechanism is discussed. For the incommensurate phase, between 67 and 30 K, the amplitude and phase modes were identified at about 20 and 10 cm−1, respectively; for the first, a critical exponent of 0.30 was determined. No evidence of NH … π hydrogen bond participation in the transitions has been detected.
|
1. ::: ::: The kinetics of the phototransformation of sterically hindered phenol inorganic solvents was investigated. The singlet state is the photochemically active state. The phenol is consumed according to a first-order law. The quantum yields of the phototransformation for the investigated phenol in various solvents amount to ∼ 10−2−10−3. ::: ::: ::: ::: ::: 2. ::: ::: It was found that the phototransformation of phenol is accelerated in alcohols, and this was explained by chemical reaction of the singlet excited molecules of the phenol with oxygen. ::: ::: ::: ::: ::: 3. ::: ::: In a frozen (77°K) solution the phototransformation of sterically hindered phenol occurs by a two-quantum mechanism.
|
eng_Latn
| 31,337 |
Spectroelectrochemical study of the anion effect on the transient redox behavior of poly(N-methylpyrrole) in anhydrous acetonitrile
|
Abstract Polymerization of N-methylpyrrole and the transient redox behaviour of the polymeric film were studied by spectroelectrochemical methods in the presence of BF4−, ClO4− and PF6− in an acetonitrile solution containing 10 ± 1 ppm of water. The doping levels and the rate of absorbance changes at different potentials were determined and compared with those obtained for polypyrrole. In poly(N-methylpyrrole) BF4− behaves in a similar way to ClO4−, in contrast with polypyrrole. This is interpreted as evidence that the BF4−-polymer interaction in polypyrrole occurs via the NH bonds which are absent in poly(N-methylpyrrole).
|
Three photolabile analogs of substrates of methionyl-tRNA synthetase were synthesized. In one, the 4-thiouridine at the 8 position of E. coli tRNAfMet was alkylated with [14C]p-azidobromoacetanilide. In the second, [14C]p-azidobenzoic acid hydrazide was condensed with the 3'-terminal dialdehyde of periodate-oxidized Escherichia coli tRNAfMet. The modified tRNAs could be purified by chromatography on benzoylated DEAE-cellulose. The third photolabile compound was [3H]methioninyl-8-azido-adenosine 5'-phosphate, an analog of the methionyl adenylate intermediate in the aminoacylation reaction. Irradiation of each of these compounds in the presence of equimolar amounts of E. coli methionyl-tRNA synthetase of micrometer concentrations gave 5-15% crosslinking.
|
eng_Latn
| 31,338 |
Teaching of Organic Chemistry and training of innovational ability for students
|
Organic chemistry is a professional basic class in existing chemistry and industry. Combined together with innovational thinking of students in teaching. , we will not only flourish teaching mood, strengthen teaching effect, but also achieve the purpose of trainging of innovational abililty and integrated stuff for students.
|
A theory of the chemical reactivity for thermo- and photo-chemical reactions is formulated in terms of the Green’s function and applied to recent observations: the photo-magnetization of a molecular crystal obtained by reduction from 2,2′-biindenyl observed by Tanaka et al., and the internal rotation of the methyl group in toluene and o-, m-, and p-fluorotoluenes observed by Ito et al.
|
eng_Latn
| 31,339 |
This reaction is an important tool for the formation of carbon -- carbon bonds .
|
The Grignard reaction is an important tool in the formation of carbon -- carbon bonds .
|
She confirmed the structure of penicillin , which Ernst Chain had proposed , and she worked out the structure of vitamin B12 .
|
eng_Latn
| 31,340 |
is urea an organic compound
|
Urea or carbamide is an organic compound with the chemical formula C O (N H 2) 2.The molecule has two âNH 2 groups joined by a carbonyl (C=O) functional group.rea serves an important role in the metabolism of nitrogen-containing compounds by animals, and is the main nitrogen-containing substance in the urine of mammals. It is colorless, odorless solid, highly soluble in water, and practically non-toxic (LD50 is 15 g/kg for rats).
|
UREA Also known as carbamide, is an organic compound of carbon, nitrogen, oxygen and hydrogen, with the formula CON2H4 or (NH2)2CO.Urea is produced commercially from two raw materials, ammonia and carbon dioxide.
|
eng_Latn
| 31,341 |
Sh− Defects in Potassium Chloride Crystals
|
The Hartree-Fock-Rutane method in a semi-empirical version of the average neglect of differential overlapping has been used for calculation of the electronic structure and the spectroscopic properties of the SH− ion in potassium chloride. The orientation of impurity defect, shifts of surrounding ions, energies of optical absorption, ratios of harmonic frequencies and the first derivatives of dipole moment function of ions in free state and in a crystal were determined. The obtained values are in a good agreement with experimentally measured data.
|
The present invention relates to a novel protein kinase for improved bicyclic heteroaryl derivatives inhibitory activity, pharmaceutically acceptable salts, hydrates and solvates thereof, for the prevention or treatment of abnormal cell growth disease comprising the bicyclic heteroaryl derivatives, their pharmaceutically acceptable salt thereof, a hydrate thereof or a solvate thereof as an active ingredient of a pharmaceutical composition.
|
eng_Latn
| 31,342 |
On some autolyzed derivatives of bovine trypsin.
|
Abstract Chromatography or incubation of dilute solutions of bovine trypsin at 4° and pH 5.5 in the presence of Ca 2+ appears to induce almost exclusively the autolytic cleavage of bond Arg 105 -Val 106 . Bonds Lys 49 -Ser 50 and Lys 131 -Ser 132 are also found substantially autolyzed in commercial trypsin preparations. Evidence is presented suggesting that trypsin still retain activity after cleavage of bonds Arg 105 -Val 106 and Lys 131 -Ser 132 . In contrast, the cleavage of bond Lys 49 -Ser 50 , close to residue His 46 , probably inactivates the enzyme.
|
A domino approach to 2-imino-1,2-dihydroquinolines and 2-imino-thiochromenes from sulfonyl azides, alkynes, and 2-acyl anilines or the potassium salt of 2-mercapto-benzaldehyde has been developed. This one-pot method is efficient and versatile.
|
eng_Latn
| 31,343 |
Efficient H2 generation from formic acid using azole complexes in water
|
Iridium azole-containing complexes are demonstrated to catalyze the dehydrogenation of formic acid into H2–CO2 (1/1) mixtures in aqueous solution in the absence of organic additives, and with a maximum turnover frequency (TOF) of 34000 h−1 at 80 °C.
|
Eight selected sulfonamide drugs were investigated as inhibitors of heat shock protein 90 (Hsp90). The investigation included simulated docking experiments to fit the selected compounds within the binding pocket of Hsp90. The selected molecules were found to readily fit within the ATP-binding pocket of Hsp90 in low-energy poses. The sulfonamides torsemide, sulfathiazole, and sulfadiazine were found to inhibit the ATPase activity of Hsp90 with IC(50) values of 1.0, 2.6, and 1.5 μM, respectively. Our results suggest that these well-established sulfonamides can be good leads for subsequent optimization into potent Hsp90 inhibitors.
|
eng_Latn
| 31,344 |
Determination of the Relative Configuration of β‐Amino Acid Esters Based on Residual Dipolar Couplings
|
Configurational and conformational characterization of two synthetic β-amino acid esters comprising an indan motif was achieved by residual dipolar couplings. We further observed that the stability of Q factors upon addition of structural noise substantially facilitates the selection of the “correct” structure. The two analyzed compounds differ by a single methyl group, which leads to a remarkable conformational change.
|
Nanofabrication on a hydrogen-terminated diamond surface is performed by controlling surface adsorbates, using a scanning probe microscope (SPM) technique. Insulated areas are successfully obtained by changing hydrogen termination to oxygen termination. The Auger electron spectrum (AES) indicated the presence of oxygen adsorbed on the modified surface area. A small isolated conductive area is fabricated, and using this structure, a metal–insulator–metal (MIM) diode-like I–V characteristic is observed. Anodic oxidation using the surface water is also suggested for our experimental results.
|
eng_Latn
| 31,345 |
Chiral Phosphoric Acid-Catalyzed Oxidative Kinetic Resolution of Indolines Based on Transfer Hydrogenation to Imines
|
The oxidative kinetic resolution of 2-substituted indoline derivatives was achieved by hydrogen transfer to imines by means of a chiral phosphoric acid catalyst. The oxidative kinetic resolution was applicable to racemic alkyl- or aryl-substituted indolines, and the remaining indolines were obtained in good yields with excellent enantioselectivities.
|
The present invention relates to a novel protein kinase for improved bicyclic heteroaryl derivatives inhibitory activity, pharmaceutically acceptable salts, hydrates and solvates thereof, for the prevention or treatment of abnormal cell growth disease comprising the bicyclic heteroaryl derivatives, their pharmaceutically acceptable salt thereof, a hydrate thereof or a solvate thereof as an active ingredient of a pharmaceutical composition.
|
eng_Latn
| 31,346 |
[Isolation, identification and degradation characterization of a polychlorinated biphenyls-degrading bacterium Pseudomonas sp. DN2].
|
A polychlorinated biphenyls-degrading bacterium DN2, using biphenyl as sole carbon source and energy source, was isolated from long-term PCBs-contaminated soil. Through morphological observation and sequence analysis of 16S rDNA, the strain was identified as Pseudomonas sp.. By identification of bphA1 core segment of biphenyl dioxygenase (BPDO) and enzyme activity assay of 2, 3-dihydroxybiphenyl-1,2-dioxygenase, the PCBs/biphenyl degradation-related genes in the bacterium was confirmed. Using GC-MS and resting cells PCBs degradation capacity test, the strain could remove 67% of the Aroclor 1242 in 3 days with 30%-90% of degradation rate of Aroclor 1242 congeners, which can contribute to the in situ bioremediation for the PCBs contaminated field.
|
Preparation of a series of dissociatively stable Pt(tripod)PR/sub 3/ complexes where tripod = CH/sub 3/C(CH/sub 2/PPh/sub 2/)/sub 3/ and PR/sub 3/ = PMe/sub 2/Ph, PMePh/sub 2/, PPh/sub 3/, P(4FC/sub 6/H/sub 4/)/sub 3/, P(3,5(CF/sub 3/)/sub 2/C/sub 6/H/sub 3/)/sub 3/, P(CH/sub 2/CH/sub 2/CN)/sub 3/, P(OMe)Ph/sub 2/, P(OMe)/sub 2/Ph, P(OMe)/sub 3/, P(POh)/sub 3/, and P(OCH/sub 2/CF/sub 3/)/sub 3/ are reported. /sup 195/Pt(/sup 1/H) and /sup 31/P(/sup 1/H) NMR data are also included. These data have expanded the data base available for the platinum (0) complexes and facilitated the drawing of empirical relationships from the platinum chemical shifts and platinum-phosphorus coupling constants. 29 refs., 1 fig., 1 tab.
|
eng_Latn
| 31,347 |
Highly Improved Efficiency of Deep-Blue Fluorescent Polymer Light-Emitting Device Based on a Novel Hole Interface Modifier with 1,3,5-Triazine Core
|
We present an investigation of deep-blue fluorescent polymer light-emitting diodes (PLEDs) with a novel functional 1,3,5-triazine core material (HQTZ) sandwiched between poly(3,4-ethylene dioxythiophene):poly(styrene sulfonic acid) layer and poly(vinylcarbazole) layer as a hole injection layer (HIL) without interface intermixing. Ultraviolet photoemission spectroscopy and Kelvin probe measurements were carried out to determine the change of anode work function influenced by the HQTZ modifier. The thin HQTZ layer can efficiently maximize the charge injection from anode to blue emitter and simultaneously enhance the hole mobility of HILs. The deep-blue device performance is remarkably improved with the maximum luminous efficiency of 4.50 cd/A enhanced by 80% and the maximum quantum efficiency of 4.93%, which is 1.8-fold higher than that of the conventional device without HQTZ layer, including a lower turn-on voltage of 3.7 V and comparable Commission Internationale de L’Eclairage coordinates of (0.16, 0.09)...
|
To gain insight into the chemical nature of drug-induced photoallergy, model studies have been carried out on the photochemical modification of proteins by tiaprofenic acid. Irradiation of decarboxylated tiaprofenic acid (DTPA) in the presence of p-cresol leads to C–C- and C–O-connected p-cresol “dimers”, together with DTPA hydrodimers. The p-cresol–DTPA cross-coupling product was not detected in this reaction. However, a product of this type is formed using a more hindered phenol, such as 2,6-di-tert-butylphenol. Similar results are obtained when tiaprofenic acid (TPA) or its methyl ester are used as photosensitizers. The observed formation of “dimers” can be related to protein photo-crosslinking, through the coupling of two tyrosine units. On the other hand, phenol–(D)TPA cross-coupling may be relevant to the understanding of drug–protein photobinding.
|
eng_Latn
| 31,348 |
Mechanism of the formation of reactive N-amidinohydrazonyl bromides and their conversion to N-amidinobenzohydrazides and 3-amino-5-aryl-1,2,4-triazoles
|
A new group of reactive N-amidinohydrazonyl halides is described. These materials may be isolated as stable hydrobromide salts but undergo rapid halide displacement on dissolution in ionizing solvents. Their solvolytic behaviour was investigated in detail in aqueous dioxan; because of the rapidity of the reaction, measurements were possible (at 25°) only in solutions of high acidity and low aqueous content. The initial product formed at all pH values was the corresponding hydrazide (formed by water attack on an intermediate azocarbonium ion) rather than the expected 3-amino-5-aryl-1,2,4-triazoles. The latter is obtained at higher temperatures from the hydrazide in basic solution (t½ca. 1 h for cyclization at pH 9 at 90°). The mechanism of formation of the N-amidinohydrazonyl bromides by direct bromination of the corresponding hydrazones was also investigated and the rate-determining step for this process was shown to be a slow geometric isomerisation (E–Z) about the azomethine bond.
|
Thermal decomposition of hexamethyldisilane (HMDS) was studied from room temperature to 1310 K using flash pyrolysis vacuum ultraviolet single-photon ionization time-of-flight mass spectrometry (VUV-SPI-TOFMS). Decomposition pathways of HMDS and initial reaction intermediates were also investigated using density functional theory (DFT) at the B3LYP/6-311++G(d,p) level. Unimolecular decomposition reactions of HMDS involving Si-Si and Si-C bond cleavage, as well as decomposition producing Me4Si and Me2Si: via a three-centered elimination, were determined as the initiation reactions. Me3SiSi(Me)2∙, Me4Si, Me3Si∙ and :SiMe2 were major products of the initiation reactions. These initial products were apt to decompose by homolytic reactions. Me2Si=CH2, :SiMe2, and other silene/silylene intermediates preferred decomposing through molecular eliminations. Both homolytic and molecular elimination reactions are important in the pyrolysis of HMDS.
|
eng_Latn
| 31,349 |
One pot synthesis of cyclohexanone oxime from nitrobenzene using a bifunctional catalyst
|
Cyclohexanone oxime is formed from nitrobenzene with 97% yield in a one-pot reaction catalysed by palladium and gold nanoparticles on carbon. The reaction is carried out under hydrogen at 60 °C and the overall transformation involves a multi-step catalysed mechanism from which intermediates and catalytically active species have been identified.
|
greatly enhanced due to the abnormally high acidity of Meldrum's acid. The magnitudes of the Hammett ( ρX and ρY) and Bronsted (βX) coefficients are rather small suggesting an early transition state. The sign and magnitude of the cross-interaction constant, ρXY (= -0.33), and kinetic isotope effects ( kH/kD 1.5-1.7) involving deuterated benzylamine nucleophilies (XC 6H4CH2ND2) are indicative of hydrogen-bonded cyclic transition state. The activation parameters, ΔH ‡ 4 kcal mol -1 and ΔS ‡ -37 e.u., are also in line with the
|
eng_Latn
| 31,350 |
Valence-bond concepts in coordination chemistry and the nature of metal-metal bonds
|
The valence-bond theory and its application to some coordination compounds of metals, especially those involving metal-metal bonds.
|
This review summarizes studies concerning the covalent binding of [14C]TCE to rat liver microsomal protein and exogenous DNA, in vitro, the enhancement of this binding by inducers of mixed-function...
|
eng_Latn
| 31,351 |
IR spectroscopy as a tool to investigate photocatalytic reactions at oxide surfaces
|
In the last years, in situ and operando IR spectroscopies are emerging as powerful tools to directly investigate the processes occurring at the surface of oxide particles during photocatalytic reactions. This paper provides a concise overview of the most used acquisition modes (transmission, ATR and DRIFT) and the related experimental setups available to study reactions under UV irradiation. Subsequently a selection of significant applications will be presented, including photocatalytic reactions in gas phase and at the solid–liquid interface. The selected examples will highlight the effectiveness of IR spectroscopy in monitoring the evolution of the reaction intermediates and products at the photocatalyst surface. This approach allows to better understand the reaction mechanism and to derive the kinetic laws, expressed in terms of surface concentrations.
|
Various (1E,3E)- and (1Z,3E)-conjugated methylthio derivatives of oxidosqualene (OS) and conjugated and non-conjugated phenylthio derivatives of OS were obtained. These compounds, designed as inhibitors of pig liver and Saccharomyces cerevisiae 2,3-oxidosqualene-lanosterol cyclases (OSC) (EC 5.4.99.7) and of Alicyclobacillus acidocaldarius squalenehopene cyclase (SHC) (EC 5.4.99.-), contain the reactive function adjacent to carbons involved in the formation of the third and the fourth cycle during OS cyclization. All the new compounds are inhibitors of OSC and SHC, with various degrees of selectivity. The conjugated methylthio derivatives behaved as potent inhibitors of S. cerevisiae OSC, whereas most of the phenylthio derivatives were especially active toward SHC.
|
eng_Latn
| 31,352 |
Immunity to tetanus: tetanus antitoxin and anti-BIIb in human sera.
|
Immunity to tetanus was investigated in 157 individuals aged between 1 and 77 years using, for the evaluation of both tetanus antitoxin and antibody to fragment BIIb (anti-BIIb), an easily performed ELISA that gave reproducible results. Among these people 72% were protected against tetanus (tetanus antitoxin titres > 0·06 IU ml−1). Anti-BIIb titres > 0·15 U ml−1 were found in 75% of the males vs 57% of the females (P 0·15 U ml−1. These data raise questions as to the significance and protective effect of anti-BIIb against tetanus.
|
Abstract A new cyano-bridged dimeric oxo-centered triruthenium complex [{Ru 3 (μ 3 -O)(μ-CH 3 COO) 6 (py) 2 }(μ-CN){Ru 3 (μ 3 -O)(μ-CH 3 COO) 6 (py)(L py-SS )}] + (py = pyridine, L py-SS = (C 5 H 4 N–CH 2 NHC(O)(CH 2 ) 4 CH(CH 2 ) 2 SS) ([ 1 ] + ) has been prepared, characterized, and confined on an Au(1 1 1) surface to form self-assembled monolayers (SAMs) ( 1/Au ). The redox and IR spectroscopic properties observed for the discrete ions are essentially preserved in its SAMs. The molecules of SAMs 1/Au stand up with the cyano groups tilted to the gold surface. The electronic structures of 1/Au in different oxidation states have been studied by in situ infrared spectroscopy monitoring the stretching modes of the cyano group. The extent of cyano-mediated electronic communications between two triruthenium units in the SAMs has been successfully tuned by simply changing the electrolyte solutions from 0.1 M n -Bu 4 NPF 6 –CH 2 Cl 2 to aqueous 0.1 M HClO 4 .
|
eng_Latn
| 31,353 |
Structure-Activity Relationships in Certain Anthelmintics
|
The problem of helminthiasis in man and other mammals has been known for many hundreds of years. In this, as in other fields of medicine, the available treatment, even 20 years ago, consisted mainly of the use of naturally occurring materials whose curative properties had become known through empirical discoveries often made centuries ago.
|
A conjugated linear molecule 3 of nanometric size containing ::: two diruthenium units as redox active linkers has been synthesised; its ::: electrochemical properties indicate molecular wire-type delocalization.
|
kor_Hang
| 31,354 |
A coumarin-labeled vinyl sulfone as tripeptidomimetic activity-based probe for cysteine cathepsins.
|
A coumarin-tetrahydroquinoline hydride 8 was synthesized as a chemical tool for fluorescent labeling. The rigidified tricyclic coumarin structure was chosen for its suitable fluorescence properties. The connection of 8 with a vinyl sulfone building block was accomplished by convergent synthesis thereby leading to the coumarin-based, tripeptidomimetic activity-based probe 10, containing a Gly-Phe-Gly motif. Probe 10 was evaluated as inactivator of the therapeutically relevant human cysteine cathepsins S, L, K, and B: it showed particularly strong inactivation of cathepsin S. The detection of recombinant and native cathepsin S was demonstrated by applying 10 to in-gel fluorescence imaging.
|
We perform a Variational Quantum Monte Carlo simulation of an interacting ::: Fermi gas confined in a three dimensional harmonic potential. This gas is considered as the precursor system from which a molecular bosonic gas is formed. Based in the results of two-body calculations for trapped atoms, we propose a family of variational many-body wave functions that takes into account the qualitative different nature of the BCS and BEC regimes as a function of the scattering length. Energies, densities and correlations functions are calculated and compared with previous results for homogeneous gases. Universality tests at the unitarity limit are also performed.
|
eng_Latn
| 31,355 |
Effects of Dietary Mannan Oligosaccharides (MOS) on Growth, Body Composition, and Intestine and Liver Histology of the Hybrid Tilapia (Oreoch romis niloticus x O. aureus)
|
This is the first study on the effects of dietary mannan oligosaccharides (MOS) on growth, body composition, and intestine and liver histology of hybrid tilapia (Oreochromis niloticus x O. aureus). Experimental diets were prepared from commercial trout diet, supplemented with MOS at levels of 0, 1.5, 3.0, or 4.5 g MOS/kg feed and randomly assigned to triplicate groups. At the end of the trial, there were no significant differences between treatment groups (p>0.05) in growth parameters (live weight gain, specific growth rate, feed conversion ratio, protein efficiency ratio) or body indices (hepatosomatic and viscerosomatic). Dry matter and protein contents increased with increasing rates of dietary MOS (p<0.05) while the mean villi length of fish fed the diet containing 1.5‰ MOS was significantly longer ( p<0.05) than that of the fish fed 4.5‰ dietary MOS. The different levels of dietary MOS had no detrimental effects on liver tissue or general fish health.
|
The alignment between the energy levels of the constituents of an organic solar cell plays a central role in determining the open-circuit voltage. However, tuning the energy levels of electrodes and/or active components via molecular modifiers placed at interfaces is not straightforward. The morphology of organic materials is commonly controlled by the substrate onto which they are deposited, and differences in morphology often lead to differences in energetics. Such a change in morphology may reduce the effect of surface modifications, as the modified surface is part of an interface with the organic material. Here we show, in an experimental model system, that by using binary molecular monolayers, in which dipolar molecules are buried in a protective nonpolar matrix, we can transform changes in the electrode surface dipole into interface dipole changes without significantly affecting the growth of pentacene onto the molecular layer, thus enabling the use of the full range of dipolar-induced open-circuit-...
|
eng_Latn
| 31,356 |
Pharmacokinetics of gentamicin following single-dose parenteral administration to goats.
|
The disposition kinetics of parenterally administered gentamicin (5 mg kg-1) has been studied in Gaddi goats. The serum concentration-time profile was described by bi-exponential and mono-exponential equations following intravenous (i.v.), intramuscular (i.m.) and subcutaneous (s.c.) administration with elimination half-life values of 0.96 +/- 0.09, 2.37 +/- 0.47 and 3.56 +/- 0.39 h, respectively. The apparent volume of distribution following i.v. administration (Vdarea: 0.26 +/- 0.041 kg-1) reflected limited extracellular distribution of the drug. The bioavailability was higher following i.m. administration (96.3%) compared to s.c. (76.9%). In view of the significantly longer biological half-life and larger area under the curve values, the s.c. route may be preferred. It is concluded that a suitable and practical dosage recommendation for gentamicin in goats would be 3.35 mg kg-1 body weight given s.c. at 12 h intervals.
|
1. ::: ::: On the basis of obtained kinetic and thermodynamic parameters of the reaction of the reversible recombination of the 2-(4′-dimethylaminophenyl)indan-1,3-dionyl radical, it is established that the most dominating influence on the rate of this reaction is nonspecific solvation. ::: ::: ::: ::: ::: 2. ::: ::: Values of rate constants of the recombination of the 2-(4′-diphenylaminophenyl)indan-1,3-dionyl radical has a V-shaped dependence on the parameter ET, Strong solvation of this radical in chloroform converts the recombination reaction from a diffusion-controlled range to a kinetic range.
|
eng_Latn
| 31,357 |
X-RAY ASSESSMENT OF ACTIVITY IN RHEUMATOID DISEASE
|
This review paper examines the limitations of X-ray techniques, and describes the results of the different methods of assessing disease progression including joint involvement in relation to the duration of the disease, and the different methods for scoring joint destruction. The application of the new X-ray technique of microfocal radiography, which produces radiographs of high magnification (x5-x10) and resolution (2 x 10(-5)m object diameter), is described. The techniques, developed by the author, provide the most accurate method of qualitative and quantitative assessment of disease progression in the wrist and hands of rheumatoid patients.
|
Two radicals can form a bond without an energetic barrier. However, the radical coupling mechanism in ruthenium-catalyzed water oxidation has been found to be associated with substantial activation energies. Here we have investigated the coupling reaction of [Ru═O(bda)L2]+ catalysts with different axial L ligands. The interaction between the two oxo radical moieties at the Ru(V) state was found to have a favorable interaction in the transition state in comparison to the prereactive complex. To further understand the existence of the activation energy, the activation energy has been decomposed into distortion energy and interaction energy. No correlation between the experimental rates and the calculated coupling barriers of different axial L was found, showing that more aspects such as solvation, supramolecular properties, and solvent dynamics likely play important roles in the equilibrium between the free RuV═O monomer and the [RuV═O···O═RuV] dimer. On the basis of our findings, we give general guidelines...
|
yue_Hant
| 31,358 |
Models of The Direct Catalytic Partial Oxidation of Light Alkanes
|
Application of homogeneous kinetic models to methane activation indicates that the higher hydrocarbon yield may be limited by homogeneous oxidation of methyl radical intermediates. In this paper, we discuss the development of a model that describes the homogeneous and heterogeneous chemistry involved in the selective oxidation of methane and light alkanes and the impact of this chemistry on alkene and higher alkane yields. We also present experimental results for methane activation and ethane dehydrogenation using stable non-volatile catalysts composed of alkaline and rare earth carbonates supported by refractory complex oxides.
|
Abstract Despite downward folding of the central π linkage in 7 and 13 , polarization of the exocyclic olefinic bonds does not surpass that seen in 1 and is not at all affected by cumulative carbomethoxy substitution of the peripheral unsaturated centers as in 9 and 10 .
|
eng_Latn
| 31,359 |
A photochemical synthesis of 3-aryl-1-methylquinolinones
|
A number of fluorescent 3-aryl-1-methylquinolinones 3 were synthesized by the regiospecific photocoupling reaction of 3-halo-1-methylquinolinones 1 with aromatic and heteroaromatic compounds 2. An unusual photocoupling product 4 was obtained in the photolysis of 3-iodo-1-methylquinolinone in the presence of benzene. The structure of 4 was unequivocally established by an X-ray crystallographic analysis.
|
Enhanced third harmonic generation is achieved in asymmetric 1D photonic crystal with graphene defect thanks to the large graphene nonlinearity and formation of a defect state that leads to perfect absorption at the pump frequency.
|
eng_Latn
| 31,360 |
Chemistry of the phenoxathiins and isosterically related heterocycles. XXXVII The synthesis and molecular structure of benzo[2, 3]naphtho[5, 6, 7-ij][1, 4]dithiepin and its 1-oxide†
|
Benzo[2, 3]naphtho[5, 6, 7-ij][1, 4]dithiepin was prepared by the condensation of the disodium salt of 1, 2-dimercaptobenzene with 1-chloro-8-nitronaphthalene. The structure was established by nmr and mass spectroscopy. A small quantity of benzo[2, 3]naphtha[5, 6, 7,ij][1, 4]dithiepin 1-oxide was also isolated. The structure was initially established by mass spectrometry. The proton spectrum was totally assigned using a combination of proton zero quantum coherence (ZQCOSY) and proton-carbon heteronuclear chemical shift correlation (HC-COSY) techniques, which also allowed the unequivocal assignment of the protonated carbon resonances. An X-ray crystal structure of the 1-oxide irrefutably confirmed the structure. The crystal was triclinic and the space group was Pl, and the data refined to a final R = 0.0353. The molecule was shown to be folded about the axis passing through the two sulfur atoms with a dihedral angle of 109.00°.
|
2-nitroaniline (2-NA) is highly toxic and environmental contaminant. It is reduced to less toxic and environmental benign product o-phenylenediamine by using different reducing agents like sodium borohydride, potassium borohydride, or hydrazine hydrate in the presence of various catalytic systems. These catalytic systems have various advantages and drawbacks. Silica-supported gold nanoparticles are frequently reported catalyst for the reduction of 2-nitroaniline in aqueous medium. In this review article, different catalytic systems reported for reduction of o-nitroaniline under various reaction conditions have been discussed. The critical review of the recent research progress for development of novel catalysts used for the reduction of 2-nitroaniline has been provided here.
|
eng_Latn
| 31,361 |
Effects of Additional Stimulants on Phenol Degradation by a Halotolerant Rhodococcus sp. JDD1H
|
A halotolerant and highly effective phenol-degrading strain, named as JDD1H, was isolated from soil contaminated by petroleum and identified as Rhodococcus sp. Phenol degradation by strain JDD1H in the presence of high salinity, especially the effect of exotic stimulants such as carbon source, nitrogen source and surfactant on phenol degradation was investigated. The results show that strain JDD1H could utilize phenol as sole carbon and energy source to grow in the presence of 5% NaCl with 16 h adaptive phase. The degradation efficiency of 150 mg/L phenol was up to 99.5% within 40 h. Lactose, cane sugar, glucose and mannitol in wide range of 100~2000 mg/L enhanced phenol degradation significantly. Organic nitrogen sources, as peptone and yeast extract, and inorganic nitrogen sources, as NH4Cl and (NH4)2SO4, accelerated phenol degradation. Tween-80 with concentration of 50-1000 mg/L restrained phenol degradation and Tween-80 of 1500-2000 mg/L could promote degradation.
|
1. ::: ::: On the basis of obtained kinetic and thermodynamic parameters of the reaction of the reversible recombination of the 2-(4′-dimethylaminophenyl)indan-1,3-dionyl radical, it is established that the most dominating influence on the rate of this reaction is nonspecific solvation. ::: ::: ::: ::: ::: 2. ::: ::: Values of rate constants of the recombination of the 2-(4′-diphenylaminophenyl)indan-1,3-dionyl radical has a V-shaped dependence on the parameter ET, Strong solvation of this radical in chloroform converts the recombination reaction from a diffusion-controlled range to a kinetic range.
|
eng_Latn
| 31,362 |
Alkylidene-Ruthenium-Tin Catalysts for the Formation of Fatty Nitriles and Esters via Cross-Metathesis of Plant Oil Derivatives†
|
The reaction of SnCl2 with the Ru−Cl bond of the Grubbs I catalyst RuCl2(═CHPh)(PCy3)2 (1) gives the complex {[Ru(═CHPh)(SnCl3)(PCy3)]2(μ-Cl)3}−[HPCy3]+ (2), but containing two diethyl ether solvate molecules. The formal insertion of SnCl2 into one Ru−Cl bond of the Hoveyda II catalyst RuCl2(═CH-C6H4OPri)(H2IMes) (3) (H2IMes = N,N′-dimesityl-4,5-dihydroimidazol-2-ylidene) results in formation of the new complex RuCl(SnCl3)(═CH-C6H4OPri)(H2IMes) (4). The X-ray analyses of 2 and 4 show the presence of very short Ru−Sn bonds (2.5834(9) A mean bond for 2 and 2.5925(12) A for 4) and the retention of short Ru═C bonds (1.895(10) and 1.825(8) A, respectively). Complex 4 shows an excellent catalytic activity for the cross-metathesis of plant oil derivatives, the C11 ω-unsaturated ester and aldehyde and the unsaturated C18 diester with acrylonitrile, and a good activity for their cross-metathesis with methyl acrylate. Good to excellent yield of α,ω-bifunctional compounds, precursors of polyesters and polyamides, we...
|
The inhibition of methyltransferases is currently of high interest, particularly in the areas of microbial infection and cell proliferation, as there have been serious attempts to develop novel anti-microbial agents. In the present investigation, a series of 11 S-adenosyl-$L$-homocysteine analogues have been synthesized and effect of these analogues on DNA methylation catalyzed by DNA methyltransferases was studied. It was found that, while $5^{\prime}$-S-(propionic acid)$5^{\prime}$-deoxy-9-($1^{\prime}$-\beta-$D$-ribofuranosyl)1,3-dideazaadenine was an activator of EcoP15I and HhaI DNA methyltransferases, $5^{\prime}$-S-(propionic acid)$5^{\prime}$-deoxy-9-($1^{\prime}$-\beta-dribofuranosyl)adenine inhibited the methyltransferases in a non-competitive manner. An understanding of the binding of analogues to DNA methyltransferases will greatly assist the design of novel anti-microbial compounds.
|
eng_Latn
| 31,363 |
Dental Implications: Adverse effects of antileptic drugs
|
Prepared by Dr R.G. Woods of the Australian Dental Association The oral adverse effects of antiepileptic drugs are...
|
Abstract A study of the effect of alkane gases on the atomic fluorescence signals of some refractory elements has been made, with a low power inductively coupled plasma (ICP) as the atomiser, and a high power ICP as the source. Detection limits are, for some elements, inferior to those obtainable by ICP-Atomic Emission Spectrometry (ICP-AES). However, an improvement by a factor of two has been obtained for tungsten by using ethanolic solutions instead of adding traces of hydrocarbon gases.
|
eng_Latn
| 31,364 |
Molecular Recognition by Novel Macrotetracyclic Cyclophanes Having Dipeptide Segments
|
Novel macrotetracyclic cyclophanes, which are constructed with four cyclophane units having eight dipeptide moieties, have been prepared and characterized by various spectroscopic methods. The guest-binding behavior of the host toward water-soluble porphyrines was examined by electronic spectroscopy.
|
A suite of programs is developed to analyze photomicrographs of the structure of nonwoven materials. Such programs are needed for deciphering the structural distinctions in multidimensional characteristics of the studied objects that contain information about their states. This allows their use for classification of objects describable by characteristics of a different physical nature without their pre-standardization. The explicit form of the proposed measures is given and the effectiveness of their use in algorithms for automatic classification is shown for clustering of the images of polypropylene spunbond nonwoven material.
|
eng_Latn
| 31,365 |
Visible-light-triggered release of nitric oxide from N-pyramidal nitrosamines.
|
Although many organic/inorganic compounds that release nitric oxide (NO) upon photoirradiation (phototriggered caged-NOs) have been reported, their photoabsorption wavelengths mostly lie in the UV region, because X-NO bonds (X=heteroatom and metal) generally have rather strong π-bond character. Thus, it is intrinsically difficult to generate organic compounds that release NO under visible light irradiation. Herein, the structures and properties of N-pyramidal nitrosamine derivatives of 7-azabicyclo[2.2.1]heptanes that release NO under visible light irradiation are described. Bathochromic shifts of the absorptions of these nitrosamines, attributed to HOMO (n)-LUMO (π*) transitions associated with the nonplanar structure of the N-NO moiety, enable the molecules to absorb visible light, which results in N-NO bond cleavage. Thus, these compounds are innate organic caged-NOs that are uncaged by visible light.
|
SUMMARY ::: ::: A new fluorescence method for histochemical demonstration of phosphatase is presented by use of riboflavin-5-phosphoric ester as substrate. Consideration of mechanism of the yellow coloring in situ of the enzyme activity is described. Distribution of riboflavin-nucleotidase in rabbit tissues is compared with nonspecific phosphatase and 5-nucleotidase.
|
eng_Latn
| 31,366 |
Molecular and Electronic Structure of Nitridochromium(V) Complexes with Macrocyclic Amine Ligands
|
Photolysis of red cis- and trans-[CrIII(cyclam)(N3)2](ClO4) (1a, 2a) (cyclam = 1,4,8,11-tetraazacyclotetradecane) in the solid state or aqueous solution by light affords the nitridochromium(V) complexes of cis- or trans-[CrV(N)(cyclam)(N3)](ClO4) (3a) and dinuclear [{trans-[CrV(N)(cyclam)]}2(μ-N3)](ClO4)3·3.5H2O (4a), respectively. 4a was converted to the bis(tetraphenylborate)−azide−2C2H5OH salt (4b). Crystallization of 4a from acetonitrileafter addition of AgClO4 and removal of AgN3yields octahedral trans-[CrV(N)(cyclam)(NCCH3)](ClO4)2 (5a). The crystal structures of 1a, 2b (which is the tetraphenylborate salt of 2a), 4a,b, 5a,b have been determined by single-crystal X-ray crystallography. All nitridochromium(V) compounds contain the trans-[CrV(N)(cyclam)]2+ fragment with an N⋮CrV moiety (1.56 ± 0.01 A). The electronic spectra of d1 configurated complexes display three low-intensity d−d bands which have been assigned in C4v symmetry as (xy) ((xz,yz) 2B2 → 2E, (xy) → (x2 − y2) 2B2 → 2B1, and (xy) → (z2) ...
|
Bioorthogonal metabolic DNA labeling with fluorochromes is a powerful strategy to visualize DNA molecules and their functions. Here, we report the development of a new DNA metabolic labeling strategy enabled by the catalyst-free bioorthogonal ligation using vinyl thioether modified thymidine and o-quinolinone quinone methide. With the newly designed vinyl thioether-modified thymidine (VTdT), we added labeling tags on cellular DNA, which could further be linked to fluorochromes in cells. Therefore, we successfully visualized the DNA localization within cells as well as single DNA molecules without other staining reagents. In addition, we further characterized this bioorthogonal DNA metabolic labeling using DNase I digestion, MS characterization of VTdT as well as VTdT-oQQF conjugate in cell nuclei or mitochondria. This technique provides a powerful strategy to study DNA in cells, which paves the way to achieve future spatiotemporal deciphering of DNA synthesis and functions.
|
eng_Latn
| 31,367 |
Electrocatalytic Water Reduction Beginning with a {Fe(NO)2}10-Reduced Dinitrosyliron Complex: Identification of Nitrogen-Doped FeOx(OH)y as a Real Heterogeneous Catalyst
|
Electron paramagnetic resonance, IR, single-crystal X-ray diffraction, and density functional theory computation reveal that the electronic structure of α-diimine-coordinated {Fe(NO)2}10-reduced dinitrosyliron complexes (DNICs) may best be described as [{Fe(NO)2}10-L•], with the added electron residing mainly on the α-diimine ligand framework. The combination of electrochemistry, gas chromatography, Fourier transform infrared, X-ray photoelectron spectroscopy, and scanning electron microscopy–energy-dispersive X-ray studies demonstrates that the cathodic potential promotes/triggers the transformation of an α-diimine-coordinated {Fe(NO)2}10-reduced DNIC into a particulate deposit on the electrode, and electrodeposited-film electrodes, CFeO and CFeNO, are kinetically dominant electrocatalysts responsible for hydrogen evolution reaction (HER) from water with quantitative Faradaic efficiency. In comparison with the CFeO electrode reaching a current density of 10 mA/cm2 with an overpotential of 333 mV for HER,...
|
The Co/Mn-mediated oxidative cross-coupling of indoles with β-keto esters via dioxygen activation under mild conditions leads to ketonization-olefination of indoles. This reaction furnishes the highly functionalized products with excellent selectivity in good yields.
|
eng_Latn
| 31,368 |
A facile and selective synthesis of hydridotrirhenium cluster under solvothermal conditions
|
Abstract The selective synthesis of pure crystals of the hydridotrirhenium cluster (μ-H) 3 Re 3 (CO) 12 via direct hydrogenation of Re 2 (CO) 10 by a solvothermal method in excellent yield is described.
|
Abstract A convenient microwave-assisted methodology is developed for the generation of 5-chloro-3-(dimethylamino)pyrazin-2(1H)-ones. The method entails a chemoselective desulfitative removal of a phenylthioether bond upon DMF/H2O treatment in the presence of sodium carbonate, yielding the desired compounds in 73–96%.
|
eng_Latn
| 31,369 |
Synthesis and Characterization of 2,6-Bis(imino)phenoxy Cobalt Complexes
|
A series of cobalt complexes bearing 2,6-bis (imino) phenoxy ligands, LCoCl2 [L = 2,6-(ArNCH)(2)CH3C6H2OH] was synthesized by the reaction of the ligand 2,6-bis(imino) phenol with the equivalent mole of cobalt dichloride, and these complexes were characterized by elemental analyses, H-1 NMR, MS and ER spectra. The structure of one complex was determined by single crystal X-ray diffraction analysis.
|
1. ::: ::: In destructive processes the organometallic compounds present in the feedstock are the least stable and begin to decompose considerably before the metal-free organic compounds. These organometallic compounds become active centers of coke formation; hence, the first portions of carboids have the highest ash contents, ::: ::: ::: ::: ::: 2. ::: ::: Different metals do not pass over into the carboids simultaneously. ::: ::: ::: ::: ::: 3. ::: ::: Removal of the first portions of the carboids formed in thermal treatment may give substantial reductions in the ash contents of cokes.
|
eng_Latn
| 31,370 |
Pulse radiolytic and electrochemical investigations of intramolecular electron transfer in carotenoporphyrins and carotenoporphyrin-quinone triads
|
Thermodynamic and kinetic aspects of intramolecular electron-transfer reactions in carotenoporphyrin dyads and carotenoid-porphyrin-quinone triads have been studied by using pulse radiolysis and cyclic voltammetry. Rapid (<1 ..mu..s) electron transfer from carotenoid radical anions to attached porphyrins has been inferred. Carotenoid cations, on the other hand, do not readily accept electrons from attached porphyrins or pyropheophorbides. Electrochemical studies provide the thermodynamic basis for these observations and also allow estimation of the energetics of photoinitiated two-step electron transfer and two-step charge recombination in triad models for photosynthetic charge separation.
|
From a physiological point of view, a close correlation has been suggested between the induction of embryogenesis, i.e. morphological differentiation, and that of anthocyanln synthesis, i.e. metabolic differentiation. I established a carrot suspension culture system in which anthocyanin synthesis and embryogenesis could be induced in the same culture and studled their relations. The results suggested that induction of anthocyanin and that of cell division, or undifferentiated growth, were the alter natures regulated by 2, 4-dichlorophenoxyacetic acid (2, 4-D). The activities of phenylalanine ammonia-lyase (PAL) and chalcone synthase (CHS) were found to play key roles in the regulation of anthocyanin synthesis by 2, 4-D. PAL and CHS genes and their transcripts were analyzed in detail, which indicated that there are two PAL genes in carrot, one being transiently and rapidly activated by stress, and the other being specifically induced during the 2, 4-D regulated anthocyanin synthesis.
|
eng_Latn
| 31,371 |
Microdetermination of caffeine in blood by gas chromatography--mass spectrometry.
|
A micromethod for the quantitative analysis of caffeine present in small quantities (100 microliter) of whole blood is described. It is based on the gas chromatographic--mass spectrometric analysis of chloroform extracts of biological samples. The method is relatively simple, rapid, specific and sensitive; as little as 20 ng of caffeine can be measured.
|
Abstract Amino modified SBA-15 (SBA-NH 2 ) was used to immobilize vanadyl (VO 2+ ) and cupric (Cu 2+ ) ions, giving SBA-NH 2 -VO 2+ and SBA-NH 2 -Cu 2+ catalysts, respectively, and the as-prepared catalysts were characterized by XRD, XPS, TEM and Nitrogen adsorption–desorption technologies. The catalytic performance of the SBA-NH 2 -VO 2+ catalysts for the oxidation of HMF can be enhanced by the use of SBA-NH 2 -Cu 2+ as the co-catalyst. Several important reaction parameters were investigated, and it was found that the reaction solvent showed a great effect on the oxidation of HMF. The highest HMF conversion and product selectivity were obtained in aromatic solvents. The highest HMF conversion reached 98.8% at 110 °C in 4-chlorotoluene, affording DFF and 2,5-furandicarboxylic acid (FDCA) with yields of 28.9% and 62.7%, respectively. More importantly, the catalysts could be recycled and showed no significant decrease of their catalytic activities.
|
eng_Latn
| 31,372 |
The metabolic defect of methionine dependence occurs frequently in human tumor cell lines
|
Methionine dependence is the inability of cells to grow when methionine (Met) is replaced by its immediate precursor homocysteine (Hcy) in the culture medium (Met−Hcy+ medium). All normal unestablished cell strains tested to date have been shown to be methionine-independent and thus grow almost as well in Met−Hcy+ medium as they do in Met+Hcy− medium. Results presented here indicate that out of 23 cell lines derived from diverse types of human tumors, 11 do not grow at all in Met−Hcy+ medium and are absolutely methionine-dependent and 3 grow only slightly in this medium. Many of the tumor cell lines tested have little else in common other than the fact that they are methionine-dependent. The high frequency of occurrence of methionine dependence in diverse types of human tumor cells indicates that methionine dependence may be an important aspect of oncogenic transformation and therapeutically exploitable.
|
Abstract EPR investigations on light-emitting Manganese centres in device-near ZnS or ZnSe thin-film layers were done. Mn 2+ centres were detected in both basic modifications of ZnS. Assertion on the crystallinity could be made. The efficiency of EPR is demonstrated by some examples.
|
eng_Latn
| 31,373 |
Crystallographic analysis of the ferredoxin reductase, BphA4, during the catalysis
|
Introduction The oxidative degradation of biphenyl/PCBs by Pseudomonas sp. strain KKS102 begins with hydroxylation of an aromatic ring by a multi-component dioxygenase, BphA. This enzyme is composed of ferredoxin reductase, ferredoxin and terminal oxygenase. BphA4 is the ferredoxin reductase component of BphA, whose crystal structure was solved at 2.3A by our group five years ago [1]. Since then, we have tried to determine the high-resolution crystal structures of the reaction intermediates of BphA4 to gain a deeper insight into the electron transport mechanism between ferredoxin and BphA4. Here we report the high-resolution data collection of BphA4 in oxidized form, its NADH complex forms (reduced and blue semiquinone forms) and reoxidized form.
|
AbstractThe dissolution of refractory PuO2 in HNO3-HF-H2O dissolvents was studied. Results showed that increasing either the HNO3 or the HF concentration increases the dissolution rate, and that formation of a Pu(IV) fluoride complex decreases the rate. It was also found that oxidation of dissolved Pu(IV) helps maintain the presence of a fluoride ion as a catalyst and is thus highly beneficial to PuO2 dissolution.
|
eng_Latn
| 31,374 |
Central nervous system effect of 2,5-hexane diol
|
Single exposure of 150, 300 and 600 mg/kg 2,5-hexanediol, (2,5 HD) a metabolite of n-hexane showed no significant effect on 3H-spiroperidol binding to corpus striatal membranes when compared with control animals, where as repeated exposure of 2,5-HD, 300 and 600 mg/kg caused a significant increase in 3H-spiroperidol binding. Data of the Scatchard analysis revealed a significant increase in the maximum number of binding sites (Bmax) without any significant alteration in the affinity of the receptor (KD). The effect of hexane diol appears to be reversible, as no significant effect was observed 7 days after the cessation of the treatment. The increase in amphetamine induced locomotor activity and apomorphine induced stereotypy in the animals exposed to repeated doses of 2,5-hexane diol suggests an increase in the sensitivity of the receptors. The biochemical and behavioral studies suggests the involvement of dopaminergic transmitter function in the neurotoxicity of 2,5-HD.
|
This work deals with the analysis of the performance and emissions of ethanol HCCI/PSCCI engines by means of a Dynamic Adaptive Chemistry (DAC) technique. The implementation of such a technique provides a reduction of the computational cost of the simulations without compromising the reliability of the results. Very accurate results, in terms of pressure and heat release rate profiles and CO, CO2 and UHC emissions, are obtained with ethanol as the only species for the DRGEP graph search both with the charge uniformly distributed in the combustion chamber and by directly injecting liquid fuel in the same chamber. The global speed up of DAC simulations is twice with respect to a full mechanism which consists of 57 species and 288 reactions and a further increase is expected when DAC is compared to very detailed kinetics.Copyright © 2012 by ASME
|
eng_Latn
| 31,375 |
Synthesis,Characterization and Photocatalytic Oxidation for 1,5-Dihydroxynaphthalene of Tetrasulfophthalocyanine and Its Metallophthalocyanine Complex
|
Tetrasulfophthalocyanine(H2PcTS) and its metal complexes(ZnPcTS,FePcTS and CoPcTS) were synthesized using potassium 4-sulfophthalonitrile as precursor.The use of dialysis and column chromatography can efficiently increase the purity of the products.The structural traits and properties were discussed by Fourier transform infrared(FTIR),ultraviolet visible(UV-Vis) and proton nuclear magnetic resonance(1H NMR) spectrometries and cyclic voltammetry(CV) methods.It has been shown that the complex properties have relationship with the substitution by sulfonic groups and coordination with central metal ions.FePcTS and H2PcTS were used as photocatalysts in oxidative degradation of 1,5-dihydroxynaphthalene in the presence of H2O2 as oxidant.It was found that FePcTS in pH=3.7 solution presented the best catalytic activity.Compared with tetrasulfoporphyrins,tetrasulfophthalocyanines may be more promising photocatalysts in practical degradation of phenol contaminants.
|
Thioxo-thioenol tautomerism was discussed in ethyl β-mercaptothiocinnamate and β-mercaptocinnamamides, in connection with their chelating abilities, through the ultraviolet absorption spectra in various solvents, and the estimation of the thioenol by the iodometry. Ethylβ-mercaptothiocinnamate and N-phenyl-β-mercaptocinnamamide were confirmed to be present mainly as the cis-thioenol form, and the equilibrium should be considered only between th thioxo and the cis-thioenol forms. On the contrary, in N-ethyl-β-mercaptocinnamamide, the trans-thioenol form should be taken into consideration in its thioxothioenol tautomerism.
|
eng_Latn
| 31,376 |
On the role of N‐7‐mercaptoheptanoyl‐O‐phospho‐L‐threonine (component B) in the enzymatic reduction of methyl‐coenzyme M to methane
|
Abstract The reduction of methyl-coenzyme M (CH3SCoM) to methane in methanogenic bacteria is dependent on component B (N-7-mercaptoheptanoyl-O-phospho-L-threonine, HSHTP). We report here that S-methyl-component B (N-7-(methylthio)heptanoyl-O-phospho-L-threonine, CH3SHTP) can substitute for neither CH3SCoM nor HSHTP in the methyl-CoM reductase reaction. Rather, CH3SHTP proved to be an inhibitor competitive with HSHTP (apparent Ki=6 μM) and noncompetitive with CH3SCoM. These results make it very unlikely that HSHTP functions as a methyl group carrier. A role for HSHTP as direct electron donor for CH3SCoM reduction to CH4is proposed.
|
Preparation of a series of dissociatively stable Pt(tripod)PR/sub 3/ complexes where tripod = CH/sub 3/C(CH/sub 2/PPh/sub 2/)/sub 3/ and PR/sub 3/ = PMe/sub 2/Ph, PMePh/sub 2/, PPh/sub 3/, P(4FC/sub 6/H/sub 4/)/sub 3/, P(3,5(CF/sub 3/)/sub 2/C/sub 6/H/sub 3/)/sub 3/, P(CH/sub 2/CH/sub 2/CN)/sub 3/, P(OMe)Ph/sub 2/, P(OMe)/sub 2/Ph, P(OMe)/sub 3/, P(POh)/sub 3/, and P(OCH/sub 2/CF/sub 3/)/sub 3/ are reported. /sup 195/Pt(/sup 1/H) and /sup 31/P(/sup 1/H) NMR data are also included. These data have expanded the data base available for the platinum (0) complexes and facilitated the drawing of empirical relationships from the platinum chemical shifts and platinum-phosphorus coupling constants. 29 refs., 1 fig., 1 tab.
|
eng_Latn
| 31,377 |
Advances in the Mechanistic Understanding of Selected Reactions of Transition Metal Polyaminecarboxylate Complexes
|
Abstract This review deals with the reaction mechanisms of polyaminecarboxylate complexes of different transition metals such as Fe, Mn, Ni, and Ru. Three types of chemical processes are treated, viz. water-exchange reactions, the binding of NO, and the activation of peroxides. In each case, the nature of the polyaminecarboxylate chelate and its influence on the underlying reaction mechanism are considered. In general, the complexes are either six- or seven-coordinate and all contain a coordinated water molecule. The lability of the latter is controlled by the nature of the polyaminecarboxylate chelate and the oxidation state of the metal ion. The binding of NO and the activation of peroxide are in turn controlled by the lability of the coordinated water molecule that is displaced during the interaction with these small molecules.
|
The present invention, a) a pyrimidylaminobenzamide compound, and b) pharmaceutical combination comprising a mTOR kinase inhibitor, and to provide a method of treating or preventing proliferative diseases using such combinations.
|
eng_Latn
| 31,378 |
Sedative effectes of midazolam in the treatment of hepatic failure patients with hepatic coma by artificial liver
|
Objective To examine sedative effectes of midazolam in the treatment of hepatic failure patients with hepatic coma by artificial liver.Metheds Twenty-eight extreme restless patients were chosen for this study.All cases were injected initial 3 mg midazolam,and then 1 mg·h-1 dose were pumped last or intermittently according to patients with restless circumstance,every day the total amount to no more than 15 mg.Results The initial use of 3 mg doses can quickly achieve satisfaction calm depth,continuous intravenous pump of 1 mg·h-1 doses can maintain effective artificial liver treatment.In 28 cases,2 cases of patients had the temporary decrease of blood pressure which can be corrected by stoping the drug.All cases did not appear respiratory inhibition.Conlusion It is safe and sedative effective of midazolam in the treatment of hepatic failure patients with hepatic coma by artificial liver.
|
We herein report a gram-scale, enantioselective synthesis of Tamiflu, in which the key trans-diamino moiety has been efficiently installed via an iron-catalyzed stereoselective olefin diazidation. This significantly improved, iron-catalyzed method is uniquely effective for highly functionalized yet electronically deactivated substrates that have been previously problematic. Preliminary catalyst structure-reactivity-stereoselectivity relationship studies revealed that both the iron catalyst and the complex substrate cooperatively modulate the stereoselectivity for diazidation. Safety assessment using both differential scanning calorimetry (DSC) and the drop weight test (DWT) has also demonstrated the feasibility of carrying out this iron-catalyzed olefin diazidation for large-scale Tamiflu synthesis.
|
eng_Latn
| 31,379 |
Nucleoside H-boranophosphonates: Synthesis and properties of a new class of nucleotide analogs
|
Nucleoside H-boranophosphonates were synthesized via the condensation reactions of appropriately protected nucleosides with monopyridinium H-boranophosphonate. The condensation reactions gave only the mono-esterified products under the optimized conditions without formation of di-esterified byproducts. Deprotection of the condensation products was achieved under basic conditions to afford the fully-deprotected nucleoside H-boranophosphonates in excellent yields.
|
The trend in antioxidant activity of four cinnamic acid antioxidants, derived on the basis of their liquid-phase phenolic O H bond dissociation enthalpies, is determined theoretically, with the aid of the polarizable continuum model at the density functional theory level. Three solvents, differing in their hydrogen-bonding ability and polarity—n-heptane, acetonitrile, and ethanol—were used to model different environmental situations. The trends in solution-phase antioxidant activity appeared different in each solvent; still, the theoretical antioxidant activity trend derived in n-heptane was in excellent agreement with the experimental one in the lipid systems and the gas-phase system. Different ortho substituents show notably different solvent effects. These results could lead to the determination of reliable antioxidant activity trends in real-solution environments of interest in food or biological science frameworks.
|
eng_Latn
| 31,380 |
Search for methane in comet P/Halley
|
A search for gaseous neutral CH4 has been conducted in the coma of comet Halley on March 20, 1986 using a Fourier Transform Spectrometer on the NASA Kuiper Airborne Observatory. In the field-of-view (41″ diam. ≙ 24,000 km) the CH4 rotational temperature is equal to the kinetic temperature of the coma molecules due to collisions in most of the region and is frozen in at the outer edge. The spectrum of the v 3 band is due to fluorescence with the R(3) to R(6) lines being most suitable for Earth-based observations. Measured upper (3 σ) limits of ~4 10−19 W cm −2 for several lines lead to a (5σ) upper limit of 4 1028 CH4 molecules per second. This value corresponds to ~4% of the water vapor production rate at the time of observation.
|
This article presents a brief overview of the soluble metal complexes that catalyze the water gas shift in homogeneous solution. Also discussed are the reaction mechanisms of the catalytic cycles that may be functioning in acidic solution and in basic solution as well as for the Reppe hydroformylation of alkenes. ::: ::: ::: Keywords: ::: ::: water gas shift; ::: hydrogen; ::: carbon monoxide; ::: ruthenium; ::: rhodium; ::: platinum; ::: iridium; ::: Reppe hydroformylation
|
eng_Latn
| 31,381 |
Radical-mediated synthesis of trifluoroethyl amines and trifluoromethyl ketones from alkyl iodides
|
Radical reaction of alkyl iodides with trifluoromethyl phenylsulfonyl oxime ether 10 and hexamethylditin at 300 nm in benzene afforded the corresponding trifluoromethyl oxime ethers 11 in high yields, which were reduced into the 2,2,2-trifluoroethyl amines with lithium aluminium hydride. The trifluoroethyl amines could be converted into the corresponding trifluoromethyl ketones by treatment with NBS and DBU.
|
Organofluorines represent a rapidly expanding proportion of molecules that are used in pharmaceuticals, diagnostics, agrochemicals, and materials. Despite the prevalence of fluorine in synthetic compounds, the known biological scope is limited to a single pathway that produces fluoroacetate. Here, we demonstrate that this pathway can be exploited as a source of fluorinated building blocks for introduction of fluorine into natural-product scaffolds. Specifically, we have constructed pathways involving two polyketide synthase systems, and we show that fluoroacetate can be used to incorporate fluorine into the polyketide backbone in vitro. We further show that fluorine can be inserted site-selectively and introduced into polyketide products in vivo. These results highlight the prospects for the production of complex fluorinated natural products using synthetic biology.
|
eng_Latn
| 31,382 |
The Nature and Function of Carotenoids in the Moderately Halophilic Bacterium Halobacillus halophilus
|
Carotenoids are widely distributed in extremophiles. Among these organisms especially C30 and C50 carotenoids are found. Here, we describe the structure and function of carotenoids in halophiles with focus on the moderately halophilic bacterium Halobacillus halophilus. H. halophilus produces an unusual C30 carotenoid. The structure was solved by HR-MS and NMR analyses as methyl glucosyl-3,4-dehydro-apo-8 -lycopenoate. Six genes could be identified that are involved in the biosynthesis of carotenoids. Together with the structural analyses of intermediates of methyl glucosyl-3,4-dehydro-apo-8 -lycopenoate produced by a pigment mutant a putative and unique biosynthesis pathway could be postulated. The isolated carotenoid and its intermediates showed a high antioxidative activity and also the protective function of these pigments could be demonstrated for H. halophilus.
|
We determined that the structure of the previously published highly efficient blue electroluminescent borate complex, lithium tetra(2-methyl-8-hydroxyquinolato) boron, does not contain boron. Rather, it is the lithium salt of 2-methyl-8-hydroxyquinoline.
|
eng_Latn
| 31,383 |
Enantiomeric products formed via different mechanisms: asymmetric hydrogenation of an α,β-unsaturated carboxylic acid involving a Ru(CH3COO)2[(R)-binap] catalyst
|
Abstract Hydrogenation of ( Z )-3-phenyl-2-butenoic acid with a Ru(CH 3 COO) 2 [( R )-binap] (BINAP=2,2′-bis(diphenylphosphino)-1,1′-binaphthyl) catalyst in methanol gives ( S )-3-phenyl-2-butanoic acid and its R enantiomer in a 97:3 (4 atm) to 94:6 (100 atm) ratio in quantitative yield. Both hydrogen gas and protic methanol participate in the saturation of the olefinic bond. Analysis of the products obtained using ( Z )-3-phenyl-2-butenoic acid-3- 13 C and either H 2 , a 1:1 H 2 –D 2 mixture, or D 2 in CH 3 OD indicates that several catalytic cycles are operative, showing different reactivity and stereoselectivity. The major S enantiomer was formed primarily by the standard Ru monohydride mechanism, whereas the minor R isomer is produced via more complicated routes.
|
A method of manufacturing a strongly adherent coating on an inorganic or organic base, on a) an inorganic or organic base, low-temperature plasma treatment, subjected to corona discharge treatment or flame treatment, b) on the inorganic or organic substrate, one more photoinitiators or mixtures of photoinitiators with monomers or / and oligomers containing at least one ethylenically unsaturated group, or solutions of the above materials, applying the suspension or emulsion, and optionally, c) using suitable methods, or dry these foregoing materials, and the method of irradiating with / or electromagnetic waves, the formula (I), (II), (III) and / or (IV): IN-L-RG (I) , IN-L-RG 1 -L 1 -H (II), IN-L-RG 1 -L 1 -IN 1 (III), IN-L-RG 1 -L 1 - , Monoacyl phosphine, be a mono-acylphosphine oxide or monoacylphosphine sulfide photoinitiator group; L, L
|
eng_Latn
| 31,384 |
Photoelectrochemical Homocoupling of Methane under Blue Light Irradiation
|
Direct conversion of methane (CH4) into valuable chemicals with low-energy input is an important goal in the sustainable chemical industry. Herein, we report a photoelectrochemical activation of CH4 in the gas phase under visible light irradiation at room temperature. The proof-of-concept study revealed that homocoupling of CH4 to form ethane (C2H6) with high selectivity of 54% was induced by photogenerated holes over a tungsten trioxide (WO3) gas-diffusion photoanode coated with a proton-conducting ionomer in the presence of water vapor. The gas–electrolyte–solid triple-phase boundary enables the oxidation of the inert carbon–hydrogen bond of CH4, and the formation of carbon oxides and ethane with a carbon–carbon bond. The gas-phase photoelectrochemical system shows incident photon-to-current conversion efficiency of 11% under blue light at an applied voltage of 1.2 V. This work is also the first demonstration of a visible-light-driven hydrogen evolution from CH4. The hydrogen is separated from CH4 and o...
|
Modern ideas about the electronic structure of the long molecules of polymers with conjugated bonds (CBP) are examined and their various physicochemical properties are discussed from the standpoint of these hypotheses. The bibliography includes 162 references.
|
eng_Latn
| 31,385 |
Characterization of Recombinant Dioxygenase from Bacillus thuringiensis
|
l-isoleucine dioxygenase (IDO) was considered as an important industrial biocatalyst for 4-hydroxyisoleucine synthesis. TIDO encoding gene tido from Bacillus thuringiensis TUST-1 was cloned and expressed to detect enzymatic characteristics of recombined IDO. Sequence analysis indicated that tido was composed of 723 nucleotides encoding 240 amino acids. K m and the V max of the recombinant IDO was 0.168 mmol/L and 2.283 μmol/min/mg, respectively. Enzymatic assays sh owed that the optimum temperature and pH for the recombinant IDO was 30 °C and 8.0 respectively, furthermore, the relative activity of the enzyme remained 82.2% after 6 h’ incubation at 30 °C. This work will lay practical basis on recombinant IDO production and microbial manufacture technology of 4-hydroxyisoleucine and other amino acid derivatives.
|
We report herein a stereoselective and straightforward methodology for the synthesis of new androgen receptor ligands with (anti)-agonistic activities. Oxygen-nitrogen replacement in bicalutamide-like structures paves the way to the disclosure of a new class of analogues, including cyclized/nitrogen-substituted derivatives, with promising antiandrogen (or anabolic) activity.
|
eng_Latn
| 31,386 |
Enzymology and Molecular Genetics of Biological Halogenation
|
Heme-containing haloperoxidases were the first halogenating enzymes detected. Later vanadium-containing haloperoxidases were isolated from eukaryotic sources and perhydrolases could be isolated from bacteeria. However, elucidation of the three-dimensional structures and reaction mechanism of haloperoxidases and perhydrolases showed that they all produce more or less directly hypohalous acids leading to halogenation reactions without substrate specificity and regioselectivity. Since these properties have to be expected from halogenating enzymes involved in the biosyntheses of more complex halometabolites, it became clear that other halogenating enzymes must exist. Cloning and characterization of the biosynthetic gene clusters of many halometabolites has revealed that a new type of halogenating enzyme, the FADH2- dependent halogenases, seem to be a major player in biological halogenation. However, there is evidence that other types of halogenating enzymes and mechanism, not yet detected, must exist.
|
Abstract The binary reagent PhSeClZnCl 2 was found to be powerful for the stereocontrolled conversion of highly electrophilic olefins, such as maleate and fumarate esters, into the corresponding chloro phenylseleno derivatives in very high yields. Other olefins, such as methyl acrylate and methyl vinyl ketone, react virtually instantaneously.
|
yue_Hant
| 31,387 |
Evaluation of Diethyl-3-3′-(9,10-anthracenediyl)bis Acrylate as a Probe for Singlet Oxygen Formation during Photodynamic Therapy
|
The cell-permeable anthracene analog diethyl-3-3'-(9,10-anthracenediyl)bis acrylate (DADB) was recently identified as a highly selective probe for singlet oxygen ((1)O(2)). Now, we show that DADB can be used to monitor (1)O(2) formation in cell culture during photodynamic therapy. An atypical property of DADB is that fluorescence emission is decreased upon oxidation. Using photosensitizers that target specific organelles, we determined that DADB could detect (1)O(2) whether formed in ER, mitochondria or lysosomes. DADB fluorescence was not, however, significantly altered when the photosensitizing agent was the palladium bacteriopheophorbide termed WST11, an agent reported to produce mainly oxygen radicals upon irradiation in an aqueous environment, whereas singlet oxygen was formed in organic solvents.
|
The cover picture shows dye-sensitized solar cells (DSSCs) based on organic dyes adsorbed on a nanocrystalline TiO2 electrode. DSSCs have received considerable attention because of their high incident solar-light-to-electricity conversion efficiency and low cost of production. To create high-performance DSSCs, it is necessary to design and synthesize new and efficient organic dye photosensitizers with effective chromophores and substituents for the performance of DSSCs, which will be made possible by the exquisite molecular design and synthetic strategy of organic chemists. The background shows the architecture of the Department of Engineering, Hiroshima University, which is associated with the arrangement of organic dyes adsorbed on TiO2 electrodes. The designs and synthesis of organic dyes for DSSCs are presented in the Microreview by Y. Ooyama and Y. Harima on p. 2903 ff.
|
eng_Latn
| 31,388 |
Unusually Facile Thermal Homodienyl-[1,5]-Hydrogen Shift Reactions in Photochemically Generated Vinyl Aziridines
|
A range of photochemically generated tri- and tetracyclic vinyl aziridines have been found to undergo a general and surprisingly low temperature ring opening through a [1,5]-hydrogen shift reaction. The rate of the process was found to be highly dependent on the structure and substitution around the azirdine ring and the alkene terminus, with some substrates being observed to undergo ring opening at temperatures as low as 25 °C. The rigid nature of these polycyclic systems precludes a conformational explanation of these rate differences, and an Eyring study confirmed a negligible entropic barrier to the reaction. However, the Eyring plots for two different aziridines systems showed a significant difference in their enthalpies of activation. It is therefore believed that the levels of aziridine ring strain, as well as electronic effects, are the dominant factors in this sequence.
|
We designed and synthesized a series of hybrid molecules, in an effort to identify novel multifunctional drug candidates for Alzheimer's disease (AD), by reacting berberine with benzenediol, melatonin, and ferulic acid. The products were evaluated for: (i) the ability to inhibit multiple cholinesterases (ChEs); (ii) the capacity to prevent amyloid β (Aβ) aggregation; and (iii) antioxidant activity. All of the derivatives were better antioxidants, and inhibited Aβ aggregation to a greater extent, than the lead compound, berberine. Two of the hybrids, in particular, have the potential to be excellent candidates for AD therapy: the berberine-pyrocatechol hybrid (compound 8) was a much better inhibitor of acetylcholinesterase (AChE) than unconjugated berberine (IC(50): 0.123 vs 0.374 μM); and the berberine-hydroquinone hybrid (compound 12) displayed high antioxidant activity, could inhibit AChE (IC(50) of 0.460 μM), and had the greatest ability to inhibit Aβ aggregation.
|
eng_Latn
| 31,389 |
The surface chemical bonding investigation of CVD coated tool-steel
|
Abstract The main task of the present paper is the investigation of special cutting tool-steel, coated with TiC and TiN compounds. The tools were tested in different states by soft X-ray emission spectroscopy (SXES) in the regions of the CK α NK α FeL a and OK a emission peaks of the compounds, and they were investigated at different depths of the coating layer. The emission lines of the steel holder and its surroundings appear at depths of more than 600 nm. Shifts of the OK a peak and the fine structure changes in it show clearly the corrosion steps and states of the used tools, corresponding to the degree of use. The measurements prove clearly that heat treatment is a sensitive step in the technology of preparation of the CVD coated tool-steel. Exposure to oxygen during heat treatment decreases the life of the tool drastically.
|
Abstract Besides the common cyclisation reactions between divalent electrophiles such as Soc12, SC12, etc. and 2,2′-alkylidene-bisphenols 1 with selective attack by the two oxygens yielding dibenzo[d,g][1,3,2]dioxathiocines [1] we observed previously an unusual cyclisation of 1 with S2CI2 with a nucleophilic attack by the ortho- and para-carbon atoms (C(2) and C(4)) of bisphenol 1 [2]. We now report a new type of cyclocondensation reaction of 4,4′,6,6′-tetrasubstituted 2,2′-alkylidene-bisphenols 1 with ClSCOCl affording spiro[1,3-benzoxathiepin-4(5H),1′-cyclohexa[2,4]dien]-2,2′-diones 2 together with the cyclic carbonates 3. The structures of the products were elucidated mainly by l3C-NMR- and 1H-NMR-spectroscopy. The mode of formation of the novel spiro thiocarbonates 2 resp. the known carbonates 3 [3] is discussed.
|
eng_Latn
| 31,390 |
Synthesis and primary cytotoxicity evaluation of new imidazo[2,1-b]thiazole derivatives.
|
Abstract A series of arylidenehydrazides ( 3a – 3i ) were synthesized from [6-(4-bromophenyl)imidazo[2,1- b ]thiazol-3-yl]acetic acid hydrazide. The structures of new compounds were determined by analytical and spectral (IR, 1 H NMR, 13 C NMR, EIMS) methods. The synthesized compounds ( 3a – 3i ) were evaluated in the National Cancer Institute's 3-cell line, one dose in vitro primary cytotoxicity assay. Compounds 3a – 3c , 3h and 3i which passed the criteria for activity in this assay were scheduled automatically for evaluation against the full panel of 60 human tumour cell lines at a minimum of five concentrations at 10-fold dilutions. Compounds 3c demonstrated the most marked effects on a prostate cancer cell line (PC-3, log 10 GI 50 value
|
Azo-dye wastewater is hard to degrade due to its high content of organic compounds,its complexity of the components and high chroma.And its treatment method has been concerned extensively.TiO2 is a highly efficient catalyst which can be used in the photocatalytic degradation of organic pollutants owing to its high light stability and high reaction activity.This paper reviewed the research methods of azo-dyes wastewater by photocatalytic oxidation with TiO2.
|
eng_Latn
| 31,391 |
Some cytochemical characteristics of a phosphorylating digitonin preparation of mitochondria.
|
Abstract 1. 1. Rat-liver mitochondria were disintegrated with 1% digitanin to produce a cleared suspension from which an enzymically active preparation could be isolated by differential centrifugation. 2. 2. This preparation was examined with the electron microscope and was found to consist of aggregates of small vesicles and other material, with no intact mitochondria. The vesicles are thought to be derived from the membranes of the mitochondria. 3. 3. This preparation contained oxidative phosphorylation ability and all of the acid-soluble bound nucleotides which are found in intact mitochondria, these nucleotides being in approximately the same proportions to each other as they are in the mitochondria. Circumstantial evidence was presented that some of these compounds are necessary for phosphorylation to occur.
|
Abstract A convenient microwave-assisted methodology is developed for the generation of 5-chloro-3-(dimethylamino)pyrazin-2(1H)-ones. The method entails a chemoselective desulfitative removal of a phenylthioether bond upon DMF/H2O treatment in the presence of sodium carbonate, yielding the desired compounds in 73–96%.
|
eng_Latn
| 31,392 |
Intramolecular [2+2] photocycloaddition of N-alkenoyl β-enaminones
|
Abstract Intramolecular cycloaddition of N-alkenoyl β-enaminones occurs with high regioselectivity and diastereoselectivity leading to interesting synthons for the total synthesis of triquinanes or various sesquiterpenes.
|
A method of manufacturing a strongly adherent coating on an inorganic or organic base, on a) an inorganic or organic base, low-temperature plasma treatment, subjected to corona discharge treatment or flame treatment, b) on the inorganic or organic substrate, one more photoinitiators or mixtures of photoinitiators with monomers or / and oligomers containing at least one ethylenically unsaturated group, or solutions of the above materials, applying the suspension or emulsion, and optionally, c) using suitable methods, or dry these foregoing materials, and the method of irradiating with / or electromagnetic waves, the formula (I), (II), (III) and / or (IV): IN-L-RG (I) , IN-L-RG 1 -L 1 -H (II), IN-L-RG 1 -L 1 -IN 1 (III), IN-L-RG 1 -L 1 - , Monoacyl phosphine, be a mono-acylphosphine oxide or monoacylphosphine sulfide photoinitiator group; L, L
|
eng_Latn
| 31,393 |
Synthesis and characterization of new hydroxycarboxylate compounds obtained in the redox reaction between Fe(NO3)3 and diol
|
Abstract The paper presents experimental studies and structural investigations of two new Fe(III) hydroxycarboxylate coordination compounds. The homopolynuclear complex combinations of Fe(III) glyoxylate and succinate type were obtained in the redox reaction between Fe(NO 3 ) 3 and diols (1,2-ethanediol and 1,4-butanediol). The synthesized coordination compounds and the products formed during their thermal conversion were characterized by thermal analysis (in air and nitrogen), FT-IR and UV–VIS spectrometry, Mossbauer spectrometry, electron microscopy and XRD. By thermal decomposition of the complex combinations, at 300 °C, the well crystallized pure phase γ-Fe 2 O 3 as nanoparticles were formed.
|
Abstract The human promyelocytic leukemia cell line HL60 can be induced to differentiate into mature granulocytes by exposure to dimethyl sulfoxide. During differentiation a phospholipase activity, which releases arachidonic acid from membrane phospholipids, is expressed. Similarly, fatty acid cyclo-oxygenase activity increases 10-fold. In addition, there is a 40-fold increase in chemotactic formyl peptide receptor binding and a dramatic increase in glucose oxidation via the hexosemonophosphate shunt. The addition of indomethacin, a potent cyclo-oxygenase inhibitor, to the culture medium reduced the cyclo-oxygenase activity of HL60 cells exposed to dimethyl sulfoxide by 97%. However, the presence of indomethacin did not block the dimethyl sulfoxide induced increases in chemotactic formyl peptide receptor binding and hexosemonophosphate shunt activity.
|
eng_Latn
| 31,394 |
“Clickable” Nanoparticles for Targeted Imaging
|
Nanomaterials functionalized with targeting ligands are increasingly recognized as useful materials for molecular imaging and drug delivery. Here we describe the development and validation of azide-alkyne reactions ("click chemistry") for the rapid, site-specific modification of nanoparticles with small molecules. The facile preparation of stable nanoparticles bearing azido or alkyne groups capable of reaction with their corresponding counterpart functionalized small molecules is demonstrated. The Cu(I)-catalyzed cycloaddition of azides and alkynes is shown to be a highly efficient and selective method for point functionalization of magnetic nanoparticles. Derivatized nanoparticles bearing biotin, fluorochrome, or steroid moieties are stable for several months. Nanoparticle click chemistry will be useful for other nanomaterials, design of novel sensors, and drug delivery vehicles.
|
Abstract A simple method to engineer qutrit state with biphotons is realized. The method is based on Hong–Ou–Mandel interferometer and it is insensitive to disturbance comparing to Mach–Zehnder interferometer in principle. Moreover, a tomography procedure is employed to reconstruct the output states.
|
eng_Latn
| 31,395 |
Synthesis, crystal structure, cytotoxicity and action mechanism of Zn(ii) and Mn(ii) complexes with 4-([2,2′:6′,2′′-terpyridin]-4′-yl)-N,N-diethylaniline as a ligand
|
Two metallo-complexes, [Mn(L)2]·2ClO4 (1) and [Zn(L)(NO3)2] (2), with 4-([2,2′:6′,2′′-terpyridin]-4′-yl)-N,N-diethylaniline (L) as the ligand were synthesized and characterized. They exhibited selective cytotoxicity against BEL-7404, SK-OV-3, MGC80-3, and T-24 cell lines with IC50 values in the micromolar range (1.28–14.86 μM). Further mechanistic studies showed that complexes 1 and 2 inhibited telomerase by interacting with c-myc G-quadruplex DNA and induced cell cycle arrest at the S phase. They also caused the down-regulation of cdc25 A, cyclin A, cyclin B and CDK2, and the up-regulation of p21, p27 and p53.
|
Thermolysin [EC 3.4.24.4] was immobilized by use of a carbamoyl sulfonated urethane prepolymer. The pH dependence of apparent activity of the immobilized thermolysin was dependent on the species of the introduced diamine; compared with the one obtained with hexamethylenediamine, that prepared with l-lysine showed an optimum pH shifted to the basic side while an addition of triethylenetetramine shifted the pH profile to the acidic side. The activity after repeated use was improved by treatment with glutaraldehyde and also by an addition of cobalt(II) ion. The metal ion at the active site of the immobilized enzyme was effectively (though not completely) replaced by a treatment with ethylenediaminetetraacetic acid and the successive addition of metal ion.
|
eng_Latn
| 31,396 |
Synthesis of 1-adamantanol 2,3,3-trifluoroacrylate
|
Abstract 1-Adamantanol 2,3,3-trifluoroacrylate ( 4 ), i.e. (tricyclo- [3,3,1,13,7]dec-1-yl) 2,3,3-trifluoro-2-propenoate, was synthesized on the basis of freons as a new potential monomer.
|
A fluorometric enzyme assay was developed to evaluate the ability of a variety of compounds to bind to and/or inhibit pyroglutamyl aminopeptidase I. Among these compounds were a series of chloromethyl ketone analogues of thyrotropin releasing hormone (TRH) which had previously been shown to possess TRH-like activity in the central nervous system and have now been found to be good inhibitors of pyroglutamyl aminopeptidase. Thus, it is suggested that the observed TRH-like CNS activity could derive indirectly from inhibition of endogenous TRH degradation by pyroglutamyl aminopeptidase I.
|
eng_Latn
| 31,397 |
Oxidative Stress-Dependent Cellular Toxicity and Cytoprotection during Exposure to 9, 10-phenanthraquinone, a Component of Diesel Exhaust Particles
|
Quinones are ubiquitously present in the environment. This review summarizes the cellular toxicity of 9, 10-phenanthraquinone (9, 10-PQ), a component of diesel exhaust particles, and the cytoprotective mechanism of the nuclear factor erythroid 2-related factor 2 (Nrf2)/Kelch-like ECH-associated protein 1 (Keap1) system against oxidative stress exerted by 9, 10-PQ.
|
This work deals with the analysis of the performance and emissions of ethanol HCCI/PSCCI engines by means of a Dynamic Adaptive Chemistry (DAC) technique. The implementation of such a technique provides a reduction of the computational cost of the simulations without compromising the reliability of the results. Very accurate results, in terms of pressure and heat release rate profiles and CO, CO2 and UHC emissions, are obtained with ethanol as the only species for the DRGEP graph search both with the charge uniformly distributed in the combustion chamber and by directly injecting liquid fuel in the same chamber. The global speed up of DAC simulations is twice with respect to a full mechanism which consists of 57 species and 288 reactions and a further increase is expected when DAC is compared to very detailed kinetics.Copyright © 2012 by ASME
|
eng_Latn
| 31,398 |
Bromophenols in Marine Algae and Their Bioactivities
|
Marine algae contain various bromophenols that have been shown to possess a variety of biological activities, including antioxidant, antimicrobial, anticancer, anti-diabetic, and anti-thrombotic effects. Here, we briefly review the recent progress of these marine algal biomaterials, with respect to structure, bioactivities, and their potential application as pharmaceuticals.
|
1. ::: ::: Formation of chemiluminescence emitters during the liquid-phase oxidation of olefins by molecular oxygen can proceed through peroxide radical disproportionation or through the breakdown of intermediate molecular oxidation products. ::: ::: ::: ::: ::: 2. ::: ::: A study of the kinetics of these processes has shown that the second of these two possibilities is realized through dioxetanes and polymeric peroxides formed by chain reactions in the oxidation process.
|
eng_Latn
| 31,399 |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.