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39057367_p56
|
39057367
|
sec[5]/sec[2]/p[0]
|
6.3. Mixed Cultivar Approaches for Disease Management
| 4.03125 |
biomedical
|
Study
|
[
0.982421875,
0.0006680488586425781,
0.0171356201171875
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[
0.73046875,
0.00576019287109375,
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Plant breeding strategies can evolve beyond solely seeking resilience or adaptation and instead focus on the capacity for association, such as through intra-specific or inter-specific mixtures, as observed in agroforestry practices . These mixtures involve cultivating multiple cultivars of the same species simultaneously in a single field, with each cultivar possessing distinct agronomic traits, including disease resistance . Therefore, tolerance offers an alternative approach to managing crop diseases and pathogen outbreaks, particularly in situations where complete resistance may not be feasible or practical . The effectiveness of cultivar mixtures has been demonstrated across various pathosystems for several decades . When appropriately selected, mixtures can also enhance product quality . Cropping a mixture of susceptible and resistant cultivars in a three-quarter ratio can result in a significant reduction of almost 50% in disease severity, showcasing the effectiveness of incorporating resistant varieties .
|
[
"Akerke Maulenbay",
"Aralbek Rsaliyev"
] |
https://doi.org/10.3390/jof10070482
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999995 |
39057367_p57
|
39057367
|
sec[5]/sec[2]/p[1]
|
6.3. Mixed Cultivar Approaches for Disease Management
| 4.203125 |
biomedical
|
Study
|
[
0.98876953125,
0.001041412353515625,
0.0102081298828125
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[
0.58935546875,
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While susceptible cultivars may offer certain agronomic advantages or be preferred by growers for various reasons, the inclusion of different levels of disease-resistant cultivars in mixtures has demonstrated notable benefits in disease management . However, the recent discovery of neighbor-modulated susceptibility (NMS), which reveals how the susceptibility of a plant can be influenced by the presence of a healthy neighboring plant, has raised some concerns. The prevalence and quantitative impact of NMS in modulating susceptibility in cultivated species remain largely unknown . Growers in the United States have prioritized disease management, not only to increase yields but also to effectively manage the risks . Farmers who opt for tolerant crops may benefit from reduced yield losses, but they may inadvertently contribute to maintaining high infection pressure that can affect neighboring fields . Additionally, private companies may be hesitant to embrace tolerant cultivars to avoid raising doubts about the resistance of their varieties among customers. Therefore, educating stakeholders about tolerance and the benefits of tolerant cultivars is essential for the successful adoption of this management strategy . Traditional mixtures also often consist of cultivars with diverse phenotypes, such as variations in plant size or harvest dates, which can pose challenges in management and incur substantial costs, impeding the widespread adoption of such mixtures . In contrast, multiline mixtures, composed of lines selected for uniformity in their agronomic traits, offer a more streamlined approach to management and adoption . Mathematical models have suggested that disease eradication is feasible with an adequate number of varieties in the mixture, with an estimated minimum of approximately five varieties required for eradication. However, due to limitations in genetic resources, complete eradication may not always be achievable, necessitating a larger number of varieties, suggested to be around 10, for effective disease control .
|
[
"Akerke Maulenbay",
"Aralbek Rsaliyev"
] |
https://doi.org/10.3390/jof10070482
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999997 |
39057367_p58
|
39057367
|
sec[6]/p[0]
|
7. Conclusions
| 4.042969 |
biomedical
|
Review
|
[
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[
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In conclusion, the shift towards prioritizing tolerance over resistance in wheat pre-breeding represents a significant and promising trend in disease management strategies. The stability associated with tolerance as a host trait offers advantages by reducing the likelihood of resistance breakdown, a common issue with resistance strategies. Tolerance provides a valuable alternative approach to mitigate the impact of diseases on yields, especially in situations where complete epidemic control is challenging. Quantifying tolerance as the condition where cultivars with equal disease severity exhibit distinct quantitative responses to infection highlights its potential for integrated disease management and breeding strategies. Embracing tolerance in wheat breeding programs can lead to more sustainable and effective disease management practices, with far-reaching implications for agricultural productivity and resilience.
|
[
"Akerke Maulenbay",
"Aralbek Rsaliyev"
] |
https://doi.org/10.3390/jof10070482
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999997 |
PMC11277804_p0
|
PMC11277804
|
sec[0]/p[0]
|
1. Introduction
| 2.210938 |
other
|
Review
|
[
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0.9765625
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[
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Error analysis has been employed for quite some time, especially for complex engineering problems. Typical issues associated with error analysis are determining how errors combine, how errors propagate, or, more importantly, how errors are mitigated. Uncertainty can occur either by systematic or random errors. Frequently, propagation of uncorrelated errors is assessed by using the square root of the sum of the squares of the errors. The difficulty in this type of analysis is determining how many contributors to the total uncertainty need to be considered. Useful presentations of error analysis are contained in references . An article that uses error analysis as a teaching tool is . The content is well presented, and there is an excellent reference section. A more recent journal article that uses error analysis is . The authors provide a concise review of the basic approaches for error analysis: the reliability state function, the first-order second-moment method, the response surface method, and sensitivity analysis of errors. For the mechanical system that they considered, they were successful with their approach. They also provide a valuable reference list. It goes without saying that error analysis depends on the accuracy of the model and the data. The amount of uncertainty in each variable in the model increases the overall uncertainty. As more sources of uncertainty are considered, the overall uncertainty must increase. Without some control on uncertainty, it can become so large that the results are overshadowed by the accumulated error.
|
[
"D. Gary Harlow"
] |
https://doi.org/10.3390/ma17143383
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999997 |
PMC11277804_p1
|
PMC11277804
|
sec[0]/p[1]
|
1. Introduction
| 3.964844 |
biomedical
|
Study
|
[
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[
0.98974609375,
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The approach to be demonstrated below is a combination of scientifically or physically based modeling with adjustments made by strategically fusing an independent set of experimental data. The method was first developed for modeling the yield strength for an aircraft engine alloy . Extensive mechanistic and structural materials modeling was employed to estimate the yield strength. Due to modeling error, even though the scientific model predictions were detailed and thorough, they did not adequately match the rich databases that were to be used for validation for the yield strength prediction. The model was subsequently calibrated by using the additional yield strength data. The result was that, for this application, the calibrated yield strength was excellent for estimation and prediction. A major reason for the success in this problem is that the variability in the simulated model results and the experimental data for the yield strengths are reasonably small. Furthermore, yield strength is time-independent.
|
[
"D. Gary Harlow"
] |
https://doi.org/10.3390/ma17143383
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999995 |
PMC11277804_p2
|
PMC11277804
|
sec[0]/p[2]
|
1. Introduction
| 4 |
biomedical
|
Study
|
[
0.60400390625,
0.00109100341796875,
0.39501953125
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[
0.99462890625,
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Fatigue, obviously, is time-dependent, and, consequently, life data tend to have greater variability. The proposed methodology was applied to data from a very high cycle fatigue application for a steel . The selected data were primarily for three distinct cases. One case, for relatively high applied load, exhibited failure induced by surface abnormalities only. The amount of scatter was comparatively small. For another case, with moderate applied load, the failures were primarily induced by surface flaws, but there were a few failures that initiated at subsurface inclusions. In this case, the scatter in fatigue lives was almost four orders of magnitude. The final example was for a smaller applied load for which about half of the failures were surface-induced and the remainder were internally induced. The scatter was about three orders of magnitude. This application included uncertainty from a variety of inputs, and the bimodal behavior is an added complication. Thus, a mechanistic model that characterizes the complexities is necessary because inadequacies or oversights are contributors to uncertainty. As modeling complexity increases, the amount of extra data needed for calibration also increases. The overriding conclusion from this work is that calibration of a viable model with sufficient data improves reliability estimation and prediction. The technique seems to be appropriate and warranted.
|
[
"D. Gary Harlow"
] |
https://doi.org/10.3390/ma17143383
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999996 |
PMC11277804_p3
|
PMC11277804
|
sec[0]/p[3]
|
1. Introduction
| 3.025391 |
biomedical
|
Study
|
[
0.9375,
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[
0.99267578125,
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Based on the success of the above examples, the purpose of this work is to investigate the applicability of the methodology for two other sets of fatigue data. The integration of fatigue life data with a mechanistic model is investigated for data given in Shimokawa and Hamaguchi . This is a detailed and reputable set of data. These data have been used by others; one recent example is . Again, the strategy is to incorporate suitable additional fatigue data with mechanistic modeling to overcome inherent error and to improve subsequent reliability estimations and predictions with statistical confidence.
|
[
"D. Gary Harlow"
] |
https://doi.org/10.3390/ma17143383
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999996 |
PMC11277804_p4
|
PMC11277804
|
sec[1]/p[0]
|
2. 2024-T4 Aluminum Alloy
| 2.183594 |
other
|
Study
|
[
0.242919921875,
0.0006670951843261719,
0.75634765625
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[
0.94140625,
0.057647705078125,
0.0006856918334960938,
0.00032711029052734375
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Shimokawa and Hamaguchi established a rather large collection of fatigue data for 2024-T4 Aluminum Alloy (AA). The specimens were subjected to constant amplitude loading. They conducted tests on rectangular specimens that were 110 mm long, 52 mm wide, and 1 mm thick. The principle focus of their investigation was the effect of different types of notches or holes on fatigue life. The analyses below utilize two of their experimental programs.
|
[
"D. Gary Harlow"
] |
https://doi.org/10.3390/ma17143383
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999996 |
PMC11277804_p5
|
PMC11277804
|
sec[1]/sec[0]/p[0]
|
2.1. Center Cut Circular Hole
| 3.853516 |
biomedical
|
Study
|
[
0.89013671875,
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0.10919189453125
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[
0.998046875,
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These samples had a center cut circular hole of radius 5 mm. The fatigue data for this condition are summarized in Table 1 , which is reproduced from for completeness. Note that Δσ is the applied stress amplitude, and, for each Δσ, n is the sample size, x ¯ is the sample average, s is the sample standard deviation, and cv is the sample coefficient of variation. For the eight different values of Δσ, there were a total of 222 fatigue tests conducted. Clearly, the statistical behavior is different when Δσ is 157 MPa and greater compared to applied loads less than that. For Δσ that replicate ordinary operations, fatigue lives are usually longer with greater variability. Thus, modeling requires special consideration.
|
[
"D. Gary Harlow"
] |
https://doi.org/10.3390/ma17143383
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999997 |
PMC11277804_p6
|
PMC11277804
|
sec[1]/sec[0]/p[1]
|
2.1. Center Cut Circular Hole
| 4.15625 |
biomedical
|
Study
|
[
0.8671875,
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0.13232421875
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[
0.99853515625,
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The fatigue failure data for the 2024-T4 AA specimens with a center cut circular hole are shown in Figure 1 . The data are plotted on two-parameter Weibull probability paper. By observation, a two-parameter Weibull cumulative distribution function (cdf) is acceptable for Δσ greater than or equal to 177 MPa. For Δσ less than 177 MPa, a two-parameter Weibull cdf is not acceptable because the tails of the data deviate too much from linearity. In other words, the Anderson–Darling (AD) goodness-of-fit test indicates that a two-parameter Weibull cdf is not acceptable for these data. Possibly, a three-parameter Weibull cdf might be a better choice; however, the AD test implies that the tails of the data for Δσ, equal to 127 and 137 MPa, are sufficiently different that three-parameter Weibull cdfs are not acceptable. A log-normal cdf was proposed in . It was indicated in that paper that the log-normal cdf was a better choice than a two-parameter Weibull cdf. When Δσ equals 127 or 137 MPa, a log-normal cdf is not acceptable, according to the AD test. All of the above discussion is solely statistical modeling which is empirical, and the selection of a cdf is grounded in pragmatism. It is also appropriate to show the fatigue data in a stress-life (S-N) format. Figure 2 displays the S-N data for the specimens with a center cut circular hole. As mentioned above, it is clear graphically that the scatter is nearly the same for each Δσ above 150 MPa, but below 150 MPa, the scatter is significantly greater. For the two smallest values of Δσ, the scatter exceeds an order of magnitude.
|
[
"D. Gary Harlow"
] |
https://doi.org/10.3390/ma17143383
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999997 |
PMC11277804_p7
|
PMC11277804
|
sec[1]/sec[1]/p[0]
|
2.2. Center Cut Notch
| 4.136719 |
biomedical
|
Study
|
[
0.93017578125,
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[
0.9990234375,
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Another series of fatigue experiments for 2024-T4 AA that were included in were for the same rectangular specimens but with a different notch design. These specimens had a center cut notch 10 mm long with a maximum center width of 3 mm tapered down to a tip of radius 0.25 mm. The loading was perpendicular to the notch design. The fatigue lives are summarized in Table 2 . There were nine different values for Δσ, for a total of 252 tests for this specimen type. For Δσ greater than or equal to 147 MPa, the scatter in fatigue lives is about the same; however, when Δσ is less than 147 MPa, the scatter increases as Δσ decreases. Notice the asterisk for x ¯ , s , and cv when Δσ is 64 MPa. The reason is that the three maximum fatigue data for this case are censored. Thus, an estimate for the mean and standard deviation cannot be computed by simple averaging, as with the other values for Δσ. An excellent nonparametric estimate for the mean and standard deviation can be obtained by using the Kaplan–Meier estimator for the empirical distribution function. A well-developed presentation of the Kaplan–Meier methodology can be found in .
|
[
"D. Gary Harlow"
] |
https://doi.org/10.3390/ma17143383
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999998 |
PMC11277804_p8
|
PMC11277804
|
sec[1]/sec[1]/p[1]
|
2.2. Center Cut Notch
| 3.947266 |
biomedical
|
Study
|
[
0.87109375,
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[
0.99853515625,
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] |
For the notched specimens, the fatigue failure data are shown in Figure 3 . There are similarities to the data in Figure 1 . For the six largest values of Δσ, a two-parameter Weibull cdf is acceptable; however, for the other three conditions, it would not be acceptable. The scatter in the data coupled with the curvature makes a statistical fit more challenging. Furthermore, when Δσ is 64 MPa, there are three identical data that were censored, as indicated by the arrow in Figure 3 . Thus, the censoring has a significant effect for fitting a cdf for these data. Again, empirically selecting a suitable cdf is nontrivial, and it appears that more involved analysis may be needed. Likewise, Figure 4 is the S-N diagram for specimens with a notch. When Δσ exceeds 100 MPa, the scatter is similar, but for less than 100 MPa, the scatter increases as Δσ decreases. Again, the arrow indicates that there are three similar data that were censored.
|
[
"D. Gary Harlow"
] |
https://doi.org/10.3390/ma17143383
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999995 |
PMC11277804_p9
|
PMC11277804
|
sec[2]/p[0]
|
3. A Fatigue Crack Growth Model for the 2024-T4 AA Data
| 4.035156 |
biomedical
|
Study
|
[
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[
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The selection of an acceptable mechanistic model for any fatigue problem is difficult. This is equally true for the two examples considered herein. A nontrivial reason for this is that the experiments reported in were conducted about four decades ago. Nevertheless, a simplified fatigue crack growth model is proposed. Given a crack length of a for N cycles, the crack growth rate da/dN is assumed to be characterized by the following equation: (1) d a d N = C ( Δ K − Δ K t h ) ρ , where Δ K is the driving force and Δ K th is the threshold. The materials constants for 2024-T4 AA are C and ρ . For the 2024-T4 AA considered, ρ is assumed to be 3.33.
|
[
"D. Gary Harlow"
] |
https://doi.org/10.3390/ma17143383
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999995 |
PMC11277804_p10
|
PMC11277804
|
sec[2]/sec[0]/p[0]
|
3.1. Center Cut Circular Hole
| 4.238281 |
biomedical
|
Study
|
[
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[
0.998046875,
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Failure is assumed to be caused by a semi-circular surface crack that transitions into a through-the-thickness crack. Thus, Δ K differs for the two regimes. The driving force for a surface crack (sc) Δ K sc is assumed to be the following: (2) Δ K s c = ( 2.24 / π ) k t Δ σ π a , where 2.24/π is the geometric factor for a semi-circular crack in an infinite plate, and k t is the stress concentration factor for the hole. Using Figure 2.59 in for an estimated value for the stress concentration factor for the test specimens, k t is 2.5. Similarly, the driving force for a through-the-thickness crack (tc) Δ K tc is (3) Δ K t c = F t c ( a / r o ) Δ σ π a , where r o is the radius of the hole. Numerical values for F tc ( a / r o ) for an infinite plate under uniaxial tension containing a circular hole with a single through crack emanating from the hole perpendicular to the loading axis can be fit empirically, to within graphical resolution, by the following function: (4) F t c ( a / r o ) = 0.681 + { 0.865 / [ ( a / r o ) + 0.324 ] } ;
|
[
"D. Gary Harlow"
] |
https://doi.org/10.3390/ma17143383
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999998 |
PMC11277804_p11
|
PMC11277804
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sec[2]/sec[0]/p[1]
|
3.1. Center Cut Circular Hole
| 1.461914 |
biomedical
|
Other
|
[
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[
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See reference . Equations (3) and (4) were used for simplicity and computational convenience.
|
[
"D. Gary Harlow"
] |
https://doi.org/10.3390/ma17143383
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999996 |
PMC11277804_p12
|
PMC11277804
|
sec[2]/sec[0]/p[2]
|
3.1. Center Cut Circular Hole
| 4.113281 |
biomedical
|
Study
|
[
0.80859375,
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[
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The fatigue life N f is the sum of the cycles needed for the surface crack growth N sc and the through-the-thickness crack growth N tc , i.e., (5) N f = N s c + N t c = ∫ a o a t c d a C ( Δ K s c − Δ K t h ) n + ∫ a t c a f d a C ( Δ K t c − Δ K t h ) n , where a o is the initial damage size, a tc is the crack size at which the surface crack transitions into a through-the-thickness crack, and a f is the final crack size. The integrals in Equation (5) are clearly from Equation (1). With Δ K sc given in Equation (2), the first integral can be explicitly integrated. With Δ K tc defined by Equation (3), the second has to be integrated numerically. It is assumed that a surface crack transitions into a through-the-thickness crack at a tc , which is the solution of (6) F t c ( a t c / r o ) = ( 2.24 / π ) k t ,
|
[
"D. Gary Harlow"
] |
https://doi.org/10.3390/ma17143383
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999996 |
PMC11277804_p13
|
PMC11277804
|
sec[2]/sec[0]/p[3]
|
3.1. Center Cut Circular Hole
| 2.578125 |
biomedical
|
Other
|
[
0.869140625,
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[
0.448974609375,
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i.e., (7) a t c = r o 0.865 ( 2.24 k t / π ) − 0.681 − 0.324 .
|
[
"D. Gary Harlow"
] |
https://doi.org/10.3390/ma17143383
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
sq
| 0.857141 |
PMC11277804_p14
|
PMC11277804
|
sec[2]/sec[0]/p[4]
|
3.1. Center Cut Circular Hole
| 2 |
biomedical
|
Other
|
[
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[
0.2041015625,
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For the specimens under consideration, r o is 5 mm, which implies that a tc is 2.31 mm. Since the width of the specimen is 52 mm, a f is set to be 21 mm.
|
[
"D. Gary Harlow"
] |
https://doi.org/10.3390/ma17143383
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999998 |
PMC11277804_p15
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PMC11277804
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sec[2]/sec[0]/p[5]
|
3.1. Center Cut Circular Hole
| 4.242188 |
biomedical
|
Study
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[
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0.00004494190216064453
] |
The variables C , Δ K th , and a o are assumed to be random variables (rvs) that characterize the variability in the microstructural properties of the material. They are also assumed to be independent of the loading and time. A three-parameter Weibull cdf has been used frequently to represent material properties, and it is used for these rvs. The form used herein is given by (8) F ( x ) = 1 − exp { − [ ( x − γ ) / β ] α } , x ≥ γ where α is the shape parameter, β is the scale parameter, and γ is the minimum. An important property of Equation (8) is the mean μ, which is (9) μ = γ + β Γ ( 1 + 1 / α ) , where Γ (∙) is the Gamma function. Another significant characteristic is the cv , which is (10) c v = β Γ ( 1 + 2 / α ) − Γ 2 ( 1 + 1 / α ) γ + β Γ ( 1 + 1 / α ) .
|
[
"D. Gary Harlow"
] |
https://doi.org/10.3390/ma17143383
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999996 |
PMC11277804_p16
|
PMC11277804
|
sec[2]/sec[0]/p[6]
|
3.1. Center Cut Circular Hole
| 1.899414 |
biomedical
|
Study
|
[
0.8115234375,
0.001064300537109375,
0.187255859375
] |
[
0.8095703125,
0.1881103515625,
0.00151824951171875,
0.0007171630859375
] |
The estimated values for the parameters for the rvs are based on a conglomeration of data for 2024-T3; see . It is assumed that the material properties are sufficiently close for those of 2024-T4 that they can be used for the ensuing analyses. Table 3 contains the parameter values for the rvs used for the subsequent computations.
|
[
"D. Gary Harlow"
] |
https://doi.org/10.3390/ma17143383
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999995 |
PMC11277804_p17
|
PMC11277804
|
sec[2]/sec[0]/p[7]
|
3.1. Center Cut Circular Hole
| 2.525391 |
other
|
Study
|
[
0.315185546875,
0.0010223388671875,
0.68359375
] |
[
0.94384765625,
0.0546875,
0.0011272430419921875,
0.0004153251647949219
] |
Figure 5 shows the fatigue failure data for Δσ equal to 123, 137, and 206 MPa, which are also in Figure 1 . The dashed lines are the simulated model cdfs developed above, which is entirely independent of the fatigue lives. The model is quite good when Δσ is 123 MPa. When Δσ is 137 or 206, the model is not suitable at all. In fact, the model and the data have a maximum deviation of almost an order of magnitude when Δσ is 206 MPa. For the other values of Δσ shown in Figure 1 , the model is likewise not appropriate. Consequently, an alternative approach is required.
|
[
"D. Gary Harlow"
] |
https://doi.org/10.3390/ma17143383
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999995 |
PMC11277804_p18
|
PMC11277804
|
sec[2]/sec[1]/p[0]
|
3.2. Center Cut Notch
| 4.121094 |
biomedical
|
Study
|
[
0.94384765625,
0.0004744529724121094,
0.055755615234375
] |
[
0.998046875,
0.0014867782592773438,
0.00018167495727539062,
0.00004786252975463867
] |
For this case, the stress concentration factor used in is 3.8, and that is assumed for the ensuing computations as well. The failure, again, is assumed to be caused by a semi-circular surface crack that emanates from the notch. Since the through-the-thickness portion of the crack growth was relatively insignificant for the center cut circular hole computation, it has been omitted for this case. Thus, Δ K is assumed to have the same form as Equation (2). The rvs C and Δ K th are assumed to have the same cdfs as above because they are characteristic of the material properties. For a o , however, the surface area from which a crack emanates for the center cut circle specimens is about 20 times greater than that for the center cut notch specimens. Consequently, the cdf for a o is adjusted. The mean is increased to 19.9 × 10 −6 m and the cv is reduced to 10.4%. As the surface area under high stress decreases, the critical size for the crack initiation increases, but with fewer such sites in the field. Clearly, this needs to be verified.
|
[
"D. Gary Harlow"
] |
https://doi.org/10.3390/ma17143383
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999998 |
PMC11277804_p19
|
PMC11277804
|
sec[2]/sec[1]/p[1]
|
3.2. Center Cut Notch
| 2.414063 |
other
|
Study
|
[
0.2822265625,
0.0009112358093261719,
0.716796875
] |
[
0.93212890625,
0.06634521484375,
0.0010995864868164062,
0.0004258155822753906
] |
In Figure 6 , the fatigue failure data shown are for Δσ equal to 64, 118, and 206 MPa. These data are also part of Figure 3 . Again, the dashed lines are the cdfs computed by simulating the model, which is an independent computation from the experimental fatigue lives shown. When Δσ is 64 MPa, the model is graphically quite good. Recall that the arrow indicates censored data. For the other two cases shown, Δσ is 118 or 206, the model represents the data quite poorly. Likewise, for the other values of Δσ shown in Figure 3 , the model is unacceptable. As indicated with the center cut circular hole data, a different tactic is needed.
|
[
"D. Gary Harlow"
] |
https://doi.org/10.3390/ma17143383
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999997 |
PMC11277804_p20
|
PMC11277804
|
sec[3]/p[0]
|
4. Model Calibration for Fatigue Life Analysis
| 4.207031 |
biomedical
|
Study
|
[
0.9619140625,
0.0005135536193847656,
0.037506103515625
] |
[
0.99853515625,
0.0010623931884765625,
0.0003304481506347656,
0.00005036592483520508
] |
The modeling for the cdfs shown in Figure 5 and Figure 6 is excellent for the smallest applied load, when Δσ is 123 MPa for the center cut circular hole case and when Δσ is 64 MPa for the center cut notch condition; however, for the others, they are poor representations of the experimental data. Fortunately, these data for each Δσ are independent of the modeling, and they are available to augment the modeling results. The proposed approach to control the difference between the fatigue data and the model simulations is a straightforward empirical calibration. For each given value of the applied stress Δσ, let N i be an experimental fatigue life out of a total of n , and similarly, let Y j be one of the m simulated values for the model. Because the magnitude of fatigue lives for the data and model simulations are so large, and because they frequently exhibit substantial scatter, they are transformed initially using the natural logarithm. That is, let LN i and LY j be ln ( N i ) and ln ( Y j ), respectively. The transformation LZ j that is applied to LY j consists of a rotation and translation, so that the sample averages and sample standard deviations of the LN i and LZ j collections are identical. This is accomplished by the following equations: (11) L Z j = a L Y j + b , where (12) a = s L N s L Y and b = L N ¯ − s L N s L Y L Y ¯ , where L N ¯ and L Y ¯ are the sample averages, and s LN and s LY are the sample standard deviations of { L N i : 1 ≤ i ≤ n } and { L Y i : 1 ≤ i ≤ m } , respectively. To return to actual cycles, the LZ j values are transformed by applying the exponential function.
|
[
"D. Gary Harlow"
] |
https://doi.org/10.3390/ma17143383
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999998 |
PMC11277804_p21
|
PMC11277804
|
sec[3]/sec[0]/p[0]
|
4.1. Center Cut Circular Hole
| 4.210938 |
biomedical
|
Study
|
[
0.93994140625,
0.0007300376892089844,
0.059478759765625
] |
[
0.9990234375,
0.0006709098815917969,
0.0004534721374511719,
0.00004464387893676758
] |
Figure 7 shows the fatigue data for the center cut circular hole specimens, which are also in Figure 1 . In addition, the solid lines are the calibrated cdfs as described above. Visually, all of the calibrated cdfs characterize the data quite well. A comparison of the model cdf in Figure 5 with the calibrated cdf in Figure 7 when Δσ is 123 MPa indicates very little difference. Undoubtedly, if the model is accurate, there is little need for any calibration. When Δσ is 137 MPa or 206 MPa, however, the contrast between the model cdfs and the calibrated cdfs is striking. It clearly demonstrates the need for the translation and rotation in Equation (11). The Kolmogorov–Smirnov (KS) and AD goodness of fit tests were applied to validate the quality of the calibrated cdfs. The largest KS test statistic for the eight different values of Δσ is 0.18, which indicates that the calibrated cdf is acceptable for each value of Δσ for any significance level less than 0.20. The KS test primarily reflects the behavior of the central region of the data. The AD test implies that the cdfs are acceptable for the same significance level for each Δσ except 137 and 157 MPa. These two cdfs are not acceptable, according to the AD test. The reason for this observation is that the AD test describes the behavior in the tails of the cdf. This is apparent in Figure 7 because the tails are quite distinct from the fatigue data. In both cases, however, the cdfs are on the conservative side of the data, and would serve as suitable cdfs for prediction. Therefore, the calibrated cdfs are acceptable representations of the fatigue data. Because the calibrated cdfs are a combination of basic mechanistic modeling and experimental fatigue data, they are appropriate for estimation and prediction beyond the data range, especially for applied loads that represent typical operating conditions.
|
[
"D. Gary Harlow"
] |
https://doi.org/10.3390/ma17143383
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999995 |
PMC11277804_p22
|
PMC11277804
|
sec[3]/sec[0]/p[1]
|
4.1. Center Cut Circular Hole
| 4.050781 |
biomedical
|
Study
|
[
0.90771484375,
0.0004696846008300781,
0.09197998046875
] |
[
0.9970703125,
0.0022430419921875,
0.0005812644958496094,
0.00005334615707397461
] |
Another way in which to assess the validity of the calibrated cdfs is to consider the S-N behavior. Consider Figure 8 , which is a reproduction of Figure 2 with estimated percentile lines added. These percentiles are taken directly from the calibrated cdfs shown in Figure 7 . The solid line consists of the estimated medians. Because the calibrated cdfs are excellent representations of the central portion of the data, the estimated medians are also quite good. The dashed lines are the estimated 99% confidence bounds. The upper bound is the estimated 99.5 percentile and the lower bound is the 0.5 percentile computed from the calibrated cdfs. All the data lie between the bounds, and the bounds are very tight. Using the calibrated cdfs provides an excellent characterization of the fatigue data. As a final comment, it should be noted that the sharp corner on the lower bound when Δσ is 127 MPa corresponds to the difference in the calibrated cdf and the data in the lower tail in Figure 7 . Because the calibrated cdf is conservative, the lower bound is appropriate.
|
[
"D. Gary Harlow"
] |
https://doi.org/10.3390/ma17143383
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999997 |
PMC11277804_p23
|
PMC11277804
|
sec[3]/sec[1]/p[0]
|
4.2. Center Cut Notch
| 3.957031 |
biomedical
|
Study
|
[
0.71435546875,
0.0008091926574707031,
0.28466796875
] |
[
0.998046875,
0.0015211105346679688,
0.0004584789276123047,
0.00006216764450073242
] |
As with the above example, Figure 9 contains the fatigue data for the center cut notch specimens, which were also shown in Figure 3 , and the calibrated cdfs for each value of Δσ. Recall that the arrow in Figure 9 indicates that there are three censored data. Graphically, the calibrated cdfs characterize the data quite well. Except for the smallest data when Δσ is 98 MPa and the largest data when Δσ is 78 MPa, the data are close to the calibrated cdfs. As with the center cut circular hole case when Δσ is the smallest, i.e., 123 MPa, when Δσ is 64 MPa, the difference between the model cdf and the calibrated cdf is very small. To further assess the goodness of fit of the calibrated cdfs, the KS and AD tests were used. The KS test indicates that all of the calibrated cdfs are acceptable for any significance less than 0.20. The AD test infers that the calibrated cdfs are acceptable for any significance value less than 0.20, except when Δσ is 98 MPa, 147 MPa, and 216 MPa. The AD test implies that the calibrated cdf is not acceptable when Δσ is 98 MPa. This is clearly seen in Figure 9 because the tails are not very close to the calibrated cdf. Finally, the calibrated cdfs for Δσ equal to 147 MPa and 216 MPa are acceptable for a significance of 0.05. All things considered, the calibrated cdfs are acceptable as estimates for the center cut notch fatigue data, except for when Δσ is 98 MPa.
|
[
"D. Gary Harlow"
] |
https://doi.org/10.3390/ma17143383
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999997 |
PMC11277804_p24
|
PMC11277804
|
sec[3]/sec[1]/p[1]
|
4.2. Center Cut Notch
| 3.392578 |
biomedical
|
Study
|
[
0.97216796875,
0.00045990943908691406,
0.027313232421875
] |
[
0.9931640625,
0.00626373291015625,
0.0002663135528564453,
0.00009930133819580078
] |
Before continuing, recall that because of the censored data when Δσ equals 64 MPa, the sample average and standard deviation were estimated by using the Kaplan–Meier methodology . They are recorded in Table 2 . These estimates were used in the calibration; see Equation (12). The inference is that the proposed calibration approach is also suitable when censored data are part of the results. In fact, the methodology requires no modification as long as the sample average and standard deviation can be suitably estimated.
|
[
"D. Gary Harlow"
] |
https://doi.org/10.3390/ma17143383
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999996 |
PMC11277804_p25
|
PMC11277804
|
sec[3]/sec[1]/p[2]
|
4.2. Center Cut Notch
| 2.988281 |
biomedical
|
Study
|
[
0.83837890625,
0.0007572174072265625,
0.1607666015625
] |
[
0.98095703125,
0.018218994140625,
0.0006647109985351562,
0.00018310546875
] |
Figure 10 shows the S-N data from Figure 4 with the estimated percentile lines. As before, the median behavior is the solid line, and the 99% confidence bounds are the dashed lines; all of these are obtained from the calibrated cdfs shown in Figure 9 . The estimated medians are excellent. The confidence bounds characterize the data well. Not only are they close to the data, but they also reflect the scatter for each given value of Δσ. For the censored data, it is conceivable that the actual life is outside the confidence bounds. Even if this were the case, the bounds are excellent because they are conservative.
|
[
"D. Gary Harlow"
] |
https://doi.org/10.3390/ma17143383
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999999 |
PMC11277804_p26
|
PMC11277804
|
sec[4]/p[0]
|
5. Mean Square Error Analysis
| 3.199219 |
biomedical
|
Other
|
[
0.86572265625,
0.0005488395690917969,
0.1336669921875
] |
[
0.498046875,
0.4990234375,
0.0025482177734375,
0.00045418739318847656
] |
Mean Square Error ( MSE ) analysis is a well-known methodology to assess the validity of an estimation. The error e i is the difference between the calibrated cdf and the fatigue data. The MSE is given by (13) M S E = 1 n ∑ i = 1 n e i 2 .
|
[
"D. Gary Harlow"
] |
https://doi.org/10.3390/ma17143383
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999999 |
PMC11277804_p27
|
PMC11277804
|
sec[4]/p[1]
|
5. Mean Square Error Analysis
| 3.71875 |
biomedical
|
Study
|
[
0.78271484375,
0.0005211830139160156,
0.2166748046875
] |
[
0.857421875,
0.1407470703125,
0.0014638900756835938,
0.00023436546325683594
] |
Approximating confidence bounds with the MSE is typically done by using the square root of the MSE in Equation (13). Let σ MSE be the square root of the MSE , which can be taken as an estimate for the standard deviation. For unbiased error distributions, the standard error is equivalent to σ MSE ; see reference . Additional information for the MSE can be found in . When e i is epitomized by a normal cdf, 95% confidence bounds are estimated by adding and subtracting 2σ MSE from the calibrated cdf.
|
[
"D. Gary Harlow"
] |
https://doi.org/10.3390/ma17143383
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999998 |
PMC11277804_p28
|
PMC11277804
|
sec[4]/p[2]
|
5. Mean Square Error Analysis
| 4.105469 |
biomedical
|
Study
|
[
0.90673828125,
0.0006909370422363281,
0.092529296875
] |
[
0.9990234375,
0.0007162094116210938,
0.00025343894958496094,
0.000045359134674072266
] |
Figure 11 shows the fatigue data for three values of Δσ for the center cut notch specimens along with the calibrated cdfs from Figure 9 . The three examples shown represent the range of accuracy for the calibrated cdfs. The dashed lines for each case are the estimated 95% MSE confidence bounds. Clearly, the bounds encompass the data in each case. The widths of the bounds are dependent on the accuracy of the calibrated cdf. When Δσ is 118 MPa, the calibrated cdf is an excellent approximation for the data. The average error is only 970 cycles and the corresponding σ MSE is 8600 cycles. For this case, ±2σ MSE is only about 5% of the median behavior. Consequently, the bounds reflect the data extremely well. The calibrated cdf is not as close to the data when Δσ is 98 MPa, especially in the lower tail. Here, the average error is 3100 cycles, the corresponding σ MSE is 47,500 cycles, and ±2σ MSE is about 12% of the median. Also, the difference between the calibrated cdf and the lower confidence bound is the same as that between the calibrated cdf and the smallest fatigue data. This difference is basically 2σ MSE . For the center cut notch specimens, the MSE confidence bounds are very good for each Δσ with a complete set of fatigue data, including Δσ equal to 98 MPa. The MSE analysis is another validation of the proposed methodology.
|
[
"D. Gary Harlow"
] |
https://doi.org/10.3390/ma17143383
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999996 |
PMC11277804_p29
|
PMC11277804
|
sec[4]/p[3]
|
5. Mean Square Error Analysis
| 4.058594 |
biomedical
|
Study
|
[
0.88525390625,
0.000614166259765625,
0.114013671875
] |
[
0.99853515625,
0.0011796951293945312,
0.0002849102020263672,
0.00005078315734863281
] |
The MSE analysis for confidence bounds for the center cut circular hole data is essentially the same. When Δσ is greater than 157 MPa, the calibrated cdfs are excellent fits to the fatigue data; see Figure 7 . For these four, the MSE confidence bounds are very tight and envelop all the data, like the example when Δσ is 118 MPa in Figure 11 . For Δσ equal to 137 MPa, the MSE confidence bounds contain the data, but they are wider because of the deviation in the tails of the cdf. The σ MSE is 43,000 cycles, and ±2σ MSE is about 17% of the median. Similarly, when Δσ is 157 MPa, the MSE bounds encompass the data and are rather tight because σ MSE is only 7200 cycles, and ±2σ MSE is only 5% of the median. For the remaining two values of Δσ, the MSE is not acceptable because the error is so large in magnitude. For Δσ equal to 127 MPa, the error between the minimum data and the calibrated cdf is over 150,000 cycles. At the maximum data, the error is over 1,050,000 cycles. Altogether, the average error is 52,000 cycles and σ MSE is 340,000 cycles. When Δσ is 123 MPa, there are three data points near the median where e i is quite large. The MSE analysis is not as robust for the center cut circular hole; nevertheless, it lends credibility to the proposed methodology.
|
[
"D. Gary Harlow"
] |
https://doi.org/10.3390/ma17143383
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999996 |
PMC11277804_p30
|
PMC11277804
|
sec[5]/p[0]
|
6. Sample Size for Calibration
| 2.447266 |
other
|
Other
|
[
0.1708984375,
0.0007762908935546875,
0.828125
] |
[
0.140380859375,
0.85595703125,
0.003204345703125,
0.0005059242248535156
] |
In experimental work, the overriding issue is the number of tests required to adequately characterize the property being investigated. One of the best and most complete professional guidelines for material properties that indicates the acceptable sample size for a qualified experimental program is MMPDS , which is a scientifically developed procedure for metallic materials to assess experimental and design data so that they are acceptable for certification. MMPDS is a joint effort of government agencies and industrial, educational, and international aerospace organizations. Specifically, chapter 9 is related to statistical analysis. In Section 9.9.1.1, the comment is made that for fatigue experimentation subjected to load-controlled conditions, each load should include at least six observations to failure. While this is a good rule of thumb, it may not be sufficient to fully characterize the scatter for a given load condition.
|
[
"D. Gary Harlow"
] |
https://doi.org/10.3390/ma17143383
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999997 |
PMC11277804_p31
|
PMC11277804
|
sec[5]/p[1]
|
6. Sample Size for Calibration
| 4.09375 |
biomedical
|
Study
|
[
0.9267578125,
0.0006098747253417969,
0.07281494140625
] |
[
0.99853515625,
0.00112152099609375,
0.0002567768096923828,
0.00004845857620239258
] |
As an example, consider the center cut notch when Δσ is 69 MPa, which is shown in Figure 3 , Figure 9 and Figure 11 . This example is chosen because there is substantial scatter in the data and the calibrated cdf is an excellent fit. The sample size is 30. The main purpose of this effort was to demonstrate that the calibration method is effective and warranted. The query is whether or not less than 30 data points would have been just as effective for the calibration. Figure 12 shows the fatigue lives when Δσ equals 69 MPa, the calibrated cdf, and the MSE confidence bounds, which were also shown in Figure 11 . The only difference is that the axis for the cycles has been expanded for the graph in Figure 12 . Arbitrarily, 15 out of the 30 data points were randomly selected and used to calibrate the cdf. The white data are the ones that were randomly chosen. The corresponding calibrated cdf using just the 15 randomly selected data points is represented by the short-long dashed line. Graphically, it is reasonably similar to the cdf calibrated using all 30 data points; however, there is some deviation in the lower tail. In fact, the KS and AD tests, comparing the entire sample with the augmented cdf, indicate that it is acceptable for any level of significance less than 0.2. The MSE confidence bounds, shown as the short-short dashed lines, are a bit wider, but not overly so. Thus, a sample size of only 15 may have been acceptable. Alas, caution must be exercised because the random sample shown is excellent because the 15 data points are widely distributed over the entire sample of 30. Due to randomness, the 15 selected data points could have primarily reflected the upper tail, which would not have adequately served for calibration. Further analysis is required prior to making a definitive statement about the sample size.
|
[
"D. Gary Harlow"
] |
https://doi.org/10.3390/ma17143383
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999997 |
PMC11277804_p32
|
PMC11277804
|
sec[5]/p[2]
|
6. Sample Size for Calibration
| 4.109375 |
biomedical
|
Study
|
[
0.96044921875,
0.0004825592041015625,
0.03924560546875
] |
[
0.9990234375,
0.0007672309875488281,
0.00029349327087402344,
0.0000426173210144043
] |
To add a bit more understanding about the required sample size for quality calibration, a random selection from the 30 fatigue data points for Δσ equal to 69 MPa was repeated 1000 times. The size of the random sample was 10, 15, or 20. It should be noted that the total number of ways to select 10 or 20 data points from 30 is over 30 million, and the number of ways to choose 15 out of 30 is over 115 million. Thus, repeating the calibrations 1000 times will not lead to duplications. As expected, when only 10 data points are used for the calibration the ensuing cdf may not be acceptable. Out of the different attempts, the KS test implied that 4.9% would be unacceptable. Of the remainder, 72.6% would be acceptable for any significance below 0.2, and the rest would be acceptable with smaller a significance. The AD test was more severe because 53.0% of the calibrated cdfs were unacceptable, and only 20.7% were acceptable with a significance of 0.2. If 15 data points are used to calibrate the cdf, the results improve. Less than 1% are unacceptable, according to the KS test, but 31% are still unacceptable using the AD test. Using 20 randomly selected data points for the calibration improves the results considerably. The KS test indicates that 100% of the cdfs are acceptable with any significance less than 0.2. Because the tail behavior is more challenging, the AD test yields 11.0% that are unacceptable, and 60.9% that are acceptable with a significance less than 0.2, and the remaining attempts are acceptable with a smaller level of significance.
|
[
"D. Gary Harlow"
] |
https://doi.org/10.3390/ma17143383
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999999 |
PMC11277804_p33
|
PMC11277804
|
sec[5]/p[3]
|
6. Sample Size for Calibration
| 3.386719 |
biomedical
|
Study
|
[
0.75830078125,
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0.2412109375
] |
[
0.82763671875,
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0.0002582073211669922
] |
Certainly, the more data that are available, the better the calibration will be. The scatter in the data is not that large when Δσ is 69 MPa. Thus, fewer data may be sufficient for the calibration. In fact, 25 to 30 data points seems to be appropriate. When there is more scatter in the data, there may need to be more data in order to achieve an acceptable calibration. For example, the lower tail of the data when Δσ equals to 98 MPa is sufficiently different from the calibrated cdf that additional data would be helpful. It is difficult, a priori, to select an appropriate sample size for fatigue testing, but 30 tests for each loading condition is an excellent beginning.
|
[
"D. Gary Harlow"
] |
https://doi.org/10.3390/ma17143383
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999997 |
PMC11277804_p34
|
PMC11277804
|
sec[6]/p[0]
|
7. Results and Discussion
| 4.136719 |
biomedical
|
Study
|
[
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[
0.9990234375,
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The purpose of this effort was to demonstrate the validity and value of calibrating a cdf for fatigue life with independent experimental data. The cdf is generated from a probabilistic fatigue crack growth model using standard simulation methods. Even though the model is somewhat simplistic, the proposed methodology yields convincing results. The fatigue data considered were taken from . Two different types of specimens, based on different center cut features, were used in the analysis. One set of experiments were conducted with specimens with a center cut circular hole, and the other set used a center cut notch design. There were eight different values for the stress amplitude Δσ for the center cut circular hole specimens, and nine different ones for the center cut notch specimens. An extremely significant feature of these data sets is that the amount of data for each value of Δσ is noteworthy. All things considered, the methodology produces excellent results for estimation and prediction of the fatigue behavior. A primary motive for this process is to improve the characterization and accuracy of the cdf for fatigue life given Δσ. The calibration of the model cdf with data drastically improves the estimation because the uncertainty is controlled empirically. Certainly, as the modeling is improved, the overall accuracy is likewise better, and the reliance on the data for the calibration is diminished. This is illustrated in Figure 7 when Δσ is 123 MPa, and in Figure 9 when Δσ is 64 MPa.
|
[
"D. Gary Harlow"
] |
https://doi.org/10.3390/ma17143383
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999997 |
PMC11277804_p35
|
PMC11277804
|
sec[6]/p[1]
|
7. Results and Discussion
| 3.222656 |
biomedical
|
Study
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[
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[
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For the fatigue model, it was assumed that three rvs and their associated cdfs were sufficient to capture the majority of the variability. Even so, it was shown that most of the simulated cdfs were not an accurate characterization of the fatigue life. In fact, some cdfs differed from the corresponding data by almost an order of magnitude. Further improvements in modeling could alleviate these discrepancies. Even for cdfs when the scatter in the data was relatively small, there were significant differences.
|
[
"D. Gary Harlow"
] |
https://doi.org/10.3390/ma17143383
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999998 |
PMC11277804_p36
|
PMC11277804
|
sec[6]/p[2]
|
7. Results and Discussion
| 3.230469 |
biomedical
|
Study
|
[
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[
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The proposed calibration method was demonstrated to be quite useful for the two different types of specimens and the multiple values of Δσ for each. The validation for the approach was strongly established for all but three of the values of Δσ; however, even those three were well characterized by the S-N behavior. Nevertheless, the fatigue life model could be improved, which would lead to even more accurate calibrations. From this effort, the proposed methodology appears to be warranted. The approach should be implemented for additional applications to determine its full capability.
|
[
"D. Gary Harlow"
] |
https://doi.org/10.3390/ma17143383
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999998 |
PMC11277804_p37
|
PMC11277804
|
sec[6]/p[3]
|
7. Results and Discussion
| 2.488281 |
other
|
Other
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[
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[
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A few final comments are in order regarding the sample size needed for the calibration. For fatigue experimentation, especially for critical load bearing components, 30 tests for the key loading conditions is an excellent rule of thumb. If an accurate mechanical model for fatigue can be established, then possibly as few as 15 tests may be sufficient. The sample size is intimately related to the amount of scatter in the data. Data with large scatter will necessarily require more experiments for the calibration.
|
[
"D. Gary Harlow"
] |
https://doi.org/10.3390/ma17143383
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999994 |
PMC11277823_p0
|
PMC11277823
|
sec[0]/p[0]
|
1. Introduction
| 3.931641 |
biomedical
|
Review
|
[
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[
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Aging is a normal process characterized by gradual changes in the physiological functions of various systems, and within these processes, the loss of vestibular function can produce symptoms such as dizziness, imbalances, facial and limb weakness, confusion, or headaches . To highlight the prevalence of these problems, we had to know that approximately 15% of adults over the age of 60 experience some form of functional decline, and this percentage increases with age, affecting more than 30% of individuals over the age of 70. In fact, sarcopenia, in addition to the loss of muscle mass, strength, and function, also includes weakness, fatigue, balance problems, and difficulties in walking and standing. Both sarcopenia and pre-vestibulopathy increase the risk of falls, hospitalizations, and a decrease in quality of life .
|
[
"Marina López-García",
"José Jesús Jiménez-Rejano",
"Carmen María Suárez-Serrano"
] |
https://doi.org/10.3390/jcm13144279
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999997 |
PMC11277823_p1
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PMC11277823
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|
1. Introduction
| 1.616211 |
biomedical
|
Other
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[
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Considering the demographic transformation that Spain is undergoing, with 14.4% of the population being over 70 years old, we can say that aging has become a problem impacting public health .
|
[
"Marina López-García",
"José Jesús Jiménez-Rejano",
"Carmen María Suárez-Serrano"
] |
https://doi.org/10.3390/jcm13144279
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999997 |
PMC11277823_p2
|
PMC11277823
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|
1. Introduction
| 3.730469 |
biomedical
|
Review
|
[
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Vestibular physiotherapy has been shown to be effective in improving balance and reducing the risk of falls in cognitively intact individuals without vestibular impairment. The exercises, specifically designed for vestibular rehabilitation, help reduce dizziness and imbalances by facilitating central nervous system compensation . Since the 1990s, the main contributions in this area of knowledge have been the exercises proposed by Cawthorne and Cooksey, which have demonstrated effectiveness. These simple exercises involve the head and eyes and are used in all types of patients with nonspecific symptoms and without pathological findings .
|
[
"Marina López-García",
"José Jesús Jiménez-Rejano",
"Carmen María Suárez-Serrano"
] |
https://doi.org/10.3390/jcm13144279
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999995 |
PMC11277823_p3
|
PMC11277823
|
sec[0]/p[3]
|
1. Introduction
| 4.007813 |
biomedical
|
Review
|
[
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[
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However, given that body balance control in the elderly depends not only on the vestibular system but also on the interactions between all other systems, it seems interesting to add exercises with multiple components . This could improve the functional independence of the elderly for daily activities and body balance control. For decades, the improvement in the physical condition of older adults through the reduction of sarcopenia via exercise has been researched and proven. The trend in research suggests that this loss of strength and function appears to be reversed (with moderate to high evidence) through resistance exercises combined with aerobic and balance training, improving quality of life, and enhancing gait speed through the combination of resistance and balance exercises . Clinical Practice Guidelines emphasize the importance of multicomponent exercise (including strength, cardiovascular training, flexibility, and balance) for this population group. The Spanish Ministry of Health and Social Services has issued a consensus on frailty prevention in the National Health System with a specific guide for multicomponent exercise as a resource to be developed in the community .
|
[
"Marina López-García",
"José Jesús Jiménez-Rejano",
"Carmen María Suárez-Serrano"
] |
https://doi.org/10.3390/jcm13144279
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999998 |
PMC11277823_p4
|
PMC11277823
|
sec[0]/p[4]
|
1. Introduction
| 1.750977 |
biomedical
|
Other
|
[
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[
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During the COVID-19 pandemic, physiotherapists transitioned to providing telehealth services and recognized it as an effective platform that generated similar health outcomes .
|
[
"Marina López-García",
"José Jesús Jiménez-Rejano",
"Carmen María Suárez-Serrano"
] |
https://doi.org/10.3390/jcm13144279
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999996 |
PMC11277823_p5
|
PMC11277823
|
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|
1. Introduction
| 3.992188 |
biomedical
|
Study
|
[
0.99853515625,
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[
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Therefore, given the evidence of the independent use of both interventions in the elderly, it is necessary as an objective to determine if there is a difference in the efficacy of vestibular exercises compared to multicomponent exercises for improving functional capacity when applied in a setting, after evaluation, using technological tools to provide health care. The main hypothesis is that vestibular exercises are more effective than multicomponent exercises in improving functional capacity in individuals over 70 years old.
|
[
"Marina López-García",
"José Jesús Jiménez-Rejano",
"Carmen María Suárez-Serrano"
] |
https://doi.org/10.3390/jcm13144279
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999996 |
PMC11277823_p6
|
PMC11277823
|
sec[1]/p[0]
|
2. Materials and Methods
| 3.509766 |
clinical
|
Other
|
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[
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] |
Design: Controlled and randomized clinical trial (RCT) with two parallel groups, comparing a protocol of vestibular exercises (VE) and a control group with multicomponent exercises (ME) in individuals over 70 years old. The design of this study follows the CONSORT guidelines .
|
[
"Marina López-García",
"José Jesús Jiménez-Rejano",
"Carmen María Suárez-Serrano"
] |
https://doi.org/10.3390/jcm13144279
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999998 |
PMC11277823_p7
|
PMC11277823
|
sec[1]/p[1]
|
2. Materials and Methods
| 1.165039 |
biomedical
|
Other
|
[
0.75,
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[
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] |
The trial was registered at www.clinicaltrials.gov , with registration number NCT04894929. The study obtained the approval of the Biomedical Research Committe Biomedica of Virgen de Valme Hospital with registration number 1853-N-18, 28 April 2022. Additionally, the study protocol adheres to the ethical standards and guidelines established by the Declaration of Helsinki.
|
[
"Marina López-García",
"José Jesús Jiménez-Rejano",
"Carmen María Suárez-Serrano"
] |
https://doi.org/10.3390/jcm13144279
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999997 |
PMC11277823_p8
|
PMC11277823
|
sec[1]/p[2]
|
2. Materials and Methods
| 2.800781 |
biomedical
|
Study
|
[
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[
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] |
Participant Selection Criteria: - Women and men over 70 years old. - Subjects identified with functional limitations and a high probability of frailty through the Short Physical Performance Battery (SPPB), scoring between 4 and 9 points .
|
[
"Marina López-García",
"José Jesús Jiménez-Rejano",
"Carmen María Suárez-Serrano"
] |
https://doi.org/10.3390/jcm13144279
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999997 |
PMC11277823_p9
|
PMC11277823
|
sec[1]/p[3]
|
2. Materials and Methods
| 2.597656 |
biomedical
|
Study
|
[
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[
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] |
Exclusion Criteria: - Patients who did not have independent walking or who obtained scores above 10 or below 4 in the previous SPPB evaluation. - Polypharmacy patients (combined use of beta-blockers, sulpiride, or betahistine).
|
[
"Marina López-García",
"José Jesús Jiménez-Rejano",
"Carmen María Suárez-Serrano"
] |
https://doi.org/10.3390/jcm13144279
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999996 |
PMC11277823_p10
|
PMC11277823
|
sec[1]/p[4]
|
2. Materials and Methods
| 1.800781 |
biomedical
|
Study
|
[
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[
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] |
Recruitment: Patients over 70 years old who voluntarily attended physiotherapy at Los Bermejales Physiotherapy Clinic, Seville (Spain), where the pre- and post-evaluations took place.
|
[
"Marina López-García",
"José Jesús Jiménez-Rejano",
"Carmen María Suárez-Serrano"
] |
https://doi.org/10.3390/jcm13144279
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999998 |
PMC11277823_p11
|
PMC11277823
|
sec[1]/p[5]
|
2. Materials and Methods
| 2.876953 |
biomedical
|
Study
|
[
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[
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Intervention: An information session was conducted at the physiotherapy center for participants ( n = 44). They were evaluated (the evaluation using SPPB confirmed that the patients were in a frail or pre-frail state, allowing us to assign the exercises appropriate to their functional status) and provided written informed consent. Eligible participants were randomized into the vestibular exercise group and the multicomponent control group .
|
[
"Marina López-García",
"José Jesús Jiménez-Rejano",
"Carmen María Suárez-Serrano"
] |
https://doi.org/10.3390/jcm13144279
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999998 |
PMC11277823_p12
|
PMC11277823
|
sec[1]/p[6]
|
2. Materials and Methods
| 4.253906 |
biomedical
|
Study
|
[
0.99853515625,
0.0007376670837402344,
0.000591278076171875
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[
0.94677734375,
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Study Variables and Measurement Instruments Dependent Variables: (1) Physical function assessment: Using the SPPB scale, a discrete quantitative variable (0–12 points). The SPPB includes balance assessment, 4 m walk test, and the Time Up and Go (TUG) test. All of them demonstrate that the Short Physical Performance Battery (SPPB) is a valid and reliable measure for assessing physical performance in older adults with mild cognitive impairment (MCI). Intraclass Correlation Coefficients (ICC) above 0.7 indicate sufficient reliability for group comparisons. Additionally, SPPB subcomponents, such as the 4 m walk time (4mwt), show high reliability (ICC > 0.9), making them suitable for individual measurements over time. The Minimal Detectable Change (MDC) values provide thresholds for detecting real changes in performance, facilitating better monitoring and intervention planning. This confirms that the SPPB and its subcomponents are reliable tools for evaluating and monitoring physical performance in this population . - Classification: Severe limitation D (0–3 points), moderate/frail C (4–6 points), mild/pre-frail B (7–9 points), minimal limitation A (10–12 points). (2) Gait capacity: Authors such as O’Hoski et al. discussed the significant validity of physical function tests conducted over distances of 6 and 4 m (as we have developed), which have scientific evidence and are more feasible due to performance and space considerations. O’Hoski et al. evaluated physical function and frailty to predict adverse outcomes in older adults, confirming the validity of these tests in different configurations and their utility in clinical practice to measure dynamic balance and fall risk. Gait capacity, using the 4 m walk test, is a continuous quantitative variable measured in meters per second (m/s). A high probability of frailty is indicated by a gait speed of less than 0.8 m/s . (3) Dynamic balance capacity as a predictor of fall risk: Using the TUG test, a continuous quantitative variable measured in seconds. The national document uses a cutoff of ≥20 s for high frailty probability, but >12 s is more aligned with current literature. Among the studies that most reliably demonstrate the TUG’s effectiveness in measuring dynamic balance is the study by Barry et al. , a systematic review and meta-analysis that identified the TUG as a useful predictor of fall risk in community-dwelling older adults, highlighting its utility in clinical practice to assess functional mobility and dependency risk. This study underscores the validity and reliability of the TUG, confirming its consistency and accuracy in evaluating the functional capacity of older adults . (4) Sociodemographic Variables: Age (continuous quantitative variable measured in years) and sex (nominal dichotomous qualitative variable: Male/Female).
|
[
"Marina López-García",
"José Jesús Jiménez-Rejano",
"Carmen María Suárez-Serrano"
] |
https://doi.org/10.3390/jcm13144279
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999997 |
PMC11277823_p13
|
PMC11277823
|
sec[1]/p[7]
|
2. Materials and Methods
| 2.601563 |
biomedical
|
Study
|
[
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] |
[
0.8818359375,
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Intervention and randomization: An information session was conducted at the physiotherapy clinic for interested patients (n = 44). Participants were evaluated (the evaluation using SPPB confirmed that the patients were in a frail or pre-frail state, allowing us to assign the exercises appropriate to their functional status) and provided written informed consent.
|
[
"Marina López-García",
"José Jesús Jiménez-Rejano",
"Carmen María Suárez-Serrano"
] |
https://doi.org/10.3390/jcm13144279
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999996 |
PMC11277823_p14
|
PMC11277823
|
sec[1]/p[8]
|
2. Materials and Methods
| 3.148438 |
biomedical
|
Study
|
[
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[
0.95751953125,
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] |
The intervention was divided into two groups: an experimental vestibular exercise group and a multicomponent exercise control group. Participants were randomly assigned, by simple randomization method using the Python program, to either the multicomponent home exercise group (control group: 16 subjects) or the vestibular exercise group (experimental group: 19 patients) as detailed in the flow diagram.
|
[
"Marina López-García",
"José Jesús Jiménez-Rejano",
"Carmen María Suárez-Serrano"
] |
https://doi.org/10.3390/jcm13144279
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999995 |
PMC11277823_p15
|
PMC11277823
|
sec[1]/p[9]
|
2. Materials and Methods
| 2.023438 |
biomedical
|
Study
|
[
0.962890625,
0.0254364013671875,
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] |
[
0.8916015625,
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] |
The intervention involved 5 sessions per week for 6 weeks. Two expert physiotherapists implemented the exercises and created tailored exercise videos. Exercises were sent via email by an administrative staff member who did not participate in the evaluations. The administrator phoned the participants weekly to verify their adherence, requesting them to complete at least 90% of the sessions for re-evaluation.
|
[
"Marina López-García",
"José Jesús Jiménez-Rejano",
"Carmen María Suárez-Serrano"
] |
https://doi.org/10.3390/jcm13144279
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999997 |
PMC11277823_p16
|
PMC11277823
|
sec[1]/p[10]
|
2. Materials and Methods
| 1.529297 |
biomedical
|
Other
|
[
0.91357421875,
0.018646240234375,
0.06756591796875
] |
[
0.442626953125,
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The interventions were:
|
[
"Marina López-García",
"José Jesús Jiménez-Rejano",
"Carmen María Suárez-Serrano"
] |
https://doi.org/10.3390/jcm13144279
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999996 |
PMC11277823_p17
|
PMC11277823
|
sec[1]/p[11]
|
2. Materials and Methods
| 2.734375 |
biomedical
|
Study
|
[
0.96875,
0.0278778076171875,
0.0035686492919921875
] |
[
0.84423828125,
0.1514892578125,
0.0020198822021484375,
0.0023670196533203125
] |
A. Multicomponent Home Exercise Control Group: A 6-week therapeutic multicomponent exercise program following the ministerial guide and Vivifrail consensus ( Table 1 ). Patients received exercise videos via email and committed to 5 weekly sessions (Monday to Friday), each lasting approximately 45 min. The order and frequency of each of the exercise components performed by the participants, including cardiovascular, balance, strength, and flexibility exercises, are determined in the guide itself .
|
[
"Marina López-García",
"José Jesús Jiménez-Rejano",
"Carmen María Suárez-Serrano"
] |
https://doi.org/10.3390/jcm13144279
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999998 |
PMC11277823_p18
|
PMC11277823
|
sec[1]/p[12]
|
2. Materials and Methods
| 2.265625 |
biomedical
|
Other
|
[
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0.2232666015625,
0.0093841552734375
] |
[
0.08941650390625,
0.884765625,
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0.023223876953125
] |
B. Home Vestibular Exercise Group: Vestibular exercises were performed under the supervision of a physiotherapist on the first day to learn them, with session durations of about 20 min and 5 sessions per week, proposed by Cawthorne and Cooksey . The exercises were later recorded and sent via email to the patient for home practice . The exercises consisted of 15 repetitions without fatigue of the following:
|
[
"Marina López-García",
"José Jesús Jiménez-Rejano",
"Carmen María Suárez-Serrano"
] |
https://doi.org/10.3390/jcm13144279
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999998 |
PMC11277823_p19
|
PMC11277823
|
sec[1]/p[13]
|
2. Materials and Methods
| 1.789063 |
biomedical
|
Other
|
[
0.974609375,
0.01103973388671875,
0.01446533203125
] |
[
0.0144805908203125,
0.98046875,
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0.003444671630859375
] |
a. Eye movements while sitting and standing.
|
[
"Marina López-García",
"José Jesús Jiménez-Rejano",
"Carmen María Suárez-Serrano"
] |
https://doi.org/10.3390/jcm13144279
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999996 |
PMC11277823_p20
|
PMC11277823
|
sec[1]/p[14]
|
2. Materials and Methods
| 2.089844 |
biomedical
|
Other
|
[
0.9873046875,
0.00551605224609375,
0.007205963134765625
] |
[
0.04144287109375,
0.953125,
0.0016756057739257812,
0.00363922119140625
] |
b. Head and body movements while sitting and standing (Vorx1 and VorX2).
|
[
"Marina López-García",
"José Jesús Jiménez-Rejano",
"Carmen María Suárez-Serrano"
] |
https://doi.org/10.3390/jcm13144279
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999996 |
PMC11277823_p21
|
PMC11277823
|
sec[1]/p[15]
|
2. Materials and Methods
| 1.330078 |
other
|
Other
|
[
0.0224609375,
0.0029201507568359375,
0.974609375
] |
[
0.0011005401611328125,
0.998046875,
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0.00033164024353027344
] |
c. Standing visual tracking exercises: Hold a business card (with text lines) at eye level about 30 cm away. Slowly move the card left and right, up and down, and diagonally. Keep your head still and follow the card’s movement with your eyes, always keeping the text in focus. Repeat the exercise 10 to 15 times in each direction. As you improve, increase the speed and range of card movement, always keeping the text in focus, and gradually decrease the size of the letters on the card until you can barely read the text.
|
[
"Marina López-García",
"José Jesús Jiménez-Rejano",
"Carmen María Suárez-Serrano"
] |
https://doi.org/10.3390/jcm13144279
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999998 |
PMC11277823_p22
|
PMC11277823
|
sec[1]/p[16]
|
2. Materials and Methods
| 1.890625 |
biomedical
|
Other
|
[
0.9189453125,
0.0216217041015625,
0.05963134765625
] |
[
0.01514434814453125,
0.98046875,
0.0023822784423828125,
0.0021038055419921875
] |
d. Combined exercises involving step modifications, unstable surfaces, and walking.
|
[
"Marina López-García",
"José Jesús Jiménez-Rejano",
"Carmen María Suárez-Serrano"
] |
https://doi.org/10.3390/jcm13144279
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999997 |
PMC11277823_p23
|
PMC11277823
|
sec[1]/p[17]
|
2. Materials and Methods
| 1.873047 |
biomedical
|
Study
|
[
0.91796875,
0.069091796875,
0.01291656494140625
] |
[
0.94580078125,
0.0494384765625,
0.0015707015991210938,
0.0030517578125
] |
Follow-up: All participants, both in the control and experimental groups, kept a diary from Monday to Friday to monitor attendance and compliance. There were ultimately 30 sessions, with 7 dropouts due to nonadherence to the exercises.
|
[
"Marina López-García",
"José Jesús Jiménez-Rejano",
"Carmen María Suárez-Serrano"
] |
https://doi.org/10.3390/jcm13144279
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999996 |
PMC11277823_p24
|
PMC11277823
|
sec[1]/p[18]
|
2. Materials and Methods
| 2.783203 |
biomedical
|
Study
|
[
0.92578125,
0.07086181640625,
0.0031490325927734375
] |
[
0.60791015625,
0.38427734375,
0.0033626556396484375,
0.00446319580078125
] |
Blinding: Participants, the post-intervention evaluator, and the data analyst were blinded to the intervention to which the subjects had been assigned.
|
[
"Marina López-García",
"José Jesús Jiménez-Rejano",
"Carmen María Suárez-Serrano"
] |
https://doi.org/10.3390/jcm13144279
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999997 |
PMC11277823_p25
|
PMC11277823
|
sec[1]/p[19]
|
2. Materials and Methods
| 4.136719 |
biomedical
|
Study
|
[
0.998046875,
0.0017747879028320312,
0.0003101825714111328
] |
[
0.9970703125,
0.0025787353515625,
0.000324249267578125,
0.00018036365509033203
] |
Sample size calculation: For the calculation of the sample size, the GPower 3.1.9.7 ® software was used. Data from the study conducted by Jofré-Saldía et al. were used, where the functional capacity variable measured with the SPPB questionnaire in the experimental group obtained a post-intervention value of 11.80 points (SD = 0.47) and in the control group, 9.10 (2.40). An α error of 0.05 was considered with a study power of 80%, two groups, one-tailed hypothesis, and a proportion between groups of 1. With these data, a sample of 22 subjects was obtained, 11 in each group. A possible dropout rate of 15% was estimated, raising the sample to 26 subjects (13 in each group). Finally, 42 subjects were included, 21 in each group, with 2 dropouts in the experimental group, leaving 19 subjects, and 5 dropouts in the control group, leaving 16 subjects.
|
[
"Marina López-García",
"José Jesús Jiménez-Rejano",
"Carmen María Suárez-Serrano"
] |
https://doi.org/10.3390/jcm13144279
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999998 |
PMC11277823_p26
|
PMC11277823
|
sec[1]/p[20]
|
2. Materials and Methods
| 4.066406 |
biomedical
|
Study
|
[
0.9990234375,
0.0005502700805664062,
0.0003948211669921875
] |
[
0.9990234375,
0.0005192756652832031,
0.00016021728515625,
0.00005835294723510742
] |
Data Analysis: For data analysis, the Statistical Package for the Social Sciences (SPSS) program, version 29.0 for Windows, will be used. A descriptive analysis was performed, calculating absolute frequencies and percentages for nominal variables, while for quantitative variables, the mean and standard deviation were provided when normally distributed. For quantitative variables that did not follow a normal distribution, the median and first and third quartiles (Q1–Q3) are shown. Initial homogeneity between the experimental and control groups was then studied concerning sex, age, and pretest values of all dependent variables. Subsequently, a mixed factorial ANOVA was used for the physical function and dynamic balance variables. For gait capacity, various intragroup measurements were compared. Finally, to compare intergroup gait capacity, the difference between pre-treatment and post-intervention values was calculated, referred to as “Difference in scores.” Additionally, the percentage change in scores between pretest and post-test was calculated using the formula: Percentage change in scores = (Post-test − Pretest) ∗ 100/Pretest
|
[
"Marina López-García",
"José Jesús Jiménez-Rejano",
"Carmen María Suárez-Serrano"
] |
https://doi.org/10.3390/jcm13144279
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999997 |
PMC11277823_p27
|
PMC11277823
|
sec[1]/p[21]
|
2. Materials and Methods
| 3.992188 |
biomedical
|
Study
|
[
0.99853515625,
0.0009889602661132812,
0.0003349781036376953
] |
[
0.9990234375,
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0.00010162591934204102
] |
The values obtained in the post-test measurement of gait capacity, the “Difference in scores”, and the “Percentage change in scores” were compared, and the effect size was estimated. A “per protocol” analysis was performed to study the effects of the applied intervention. All statistical tests were performed considering a 95% confidence interval (CI) ( p -value < 0.05).
|
[
"Marina López-García",
"José Jesús Jiménez-Rejano",
"Carmen María Suárez-Serrano"
] |
https://doi.org/10.3390/jcm13144279
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999996 |
PMC11277823_p28
|
PMC11277823
|
sec[2]/p[0]
|
3. Results
| 3.228516 |
biomedical
|
Study
|
[
0.99365234375,
0.0046844482421875,
0.0014286041259765625
] |
[
0.998046875,
0.0014429092407226562,
0.0002067089080810547,
0.00021791458129882812
] |
A total of 42 subjects were included in the study, with seven dropouts: two subjects from the multicomponent exercise (ME) group and five from the vestibular exercise (VE) group, leaving a final total of 35 subjects (16 in the ME group and 19 in the VE group). Table 2 shows the initial characteristics of the subjects and the pre-intervention values of the dependent variables. No significant differences were found between the groups in any of the mentioned characteristics and dependent variables ( Table 2 ).
|
[
"Marina López-García",
"José Jesús Jiménez-Rejano",
"Carmen María Suárez-Serrano"
] |
https://doi.org/10.3390/jcm13144279
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999998 |
PMC11277823_p29
|
PMC11277823
|
sec[2]/sec[1]/p[0]
|
3.2. Dependent Variables
| 2.320313 |
biomedical
|
Study
|
[
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[
0.990234375,
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0.0003414154052734375
] |
Intragroup Comparisons of the Results Obtained in the Dependent Variables Studied Two Groups ( Table 3 ).
|
[
"Marina López-García",
"José Jesús Jiménez-Rejano",
"Carmen María Suárez-Serrano"
] |
https://doi.org/10.3390/jcm13144279
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999996 |
PMC11277823_p30
|
PMC11277823
|
sec[3]/p[0]
|
4. Discussion
| 4.085938 |
biomedical
|
Study
|
[
0.99658203125,
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0.00074005126953125
] |
[
0.513671875,
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0.480712890625,
0.0011234283447265625
] |
In the clinical trial conducted, no significant differences were found between the improvements produced by vestibular and multicomponent exercises. Both the control and experimental groups showed improvement in performance tests following their respective interventions. The difference in the total SPPB score leans toward a more significant improvement. Both EV and EM aim to combat inactivity and deconditioning. Inactivity underlies cardiovascular deterioration, insulin resistance, depression, and notably musculoskeletal disorders like sarcopenia . The European Consensus review suggests overlap in these processes, indicating that balance disorders can lead to low muscle strength, as evidenced in our results. Additionally, the consensus confirms that physical performance is linked to locomotion, involving muscles as well as central and peripheral nervous functions, including balance . This may lead us to think that, at times, physical condition may deteriorate and lead to a decline in physical performance, balance, and gait tests, while in other instances, presbivestipulopathy associated with aging may be the cause of this decrease. It is worth noting that other authors such as Velez et al. have already established that the design, following a similar study using home-based telerehabilitation guided by exercises, emerges as a viable strategy to enhance functional capacities in older adults. This study highlights key aspects influencing the successful implementation of home-based rehabilitation and telerehabilitation services. They examined 223 studies and analyzed 53 in depth. The findings suggest that both in-person and telerehabilitation services are perceived as convenient and less disruptive to daily activities, especially in the COVID-19 context. Additionally, these services can promote self-management and empower patients. The review indicates that well-guided telerehabilitation, complemented by in-person sessions, is a promising strategy for improving functional capacities in older adults. The author also established that home-based telerehabilitation guided by exercises is a viable strategy for enhancing functional capacities in older adults.
|
[
"Marina López-García",
"José Jesús Jiménez-Rejano",
"Carmen María Suárez-Serrano"
] |
https://doi.org/10.3390/jcm13144279
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999995 |
PMC11277823_p31
|
PMC11277823
|
sec[3]/p[1]
|
4. Discussion
| 4.074219 |
biomedical
|
Study
|
[
0.99951171875,
0.0003299713134765625,
0.00020492076873779297
] |
[
0.9990234375,
0.0002655982971191406,
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0.00006520748138427734
] |
In individuals over 70 years of age, the frequent overlap of pathological conditions poses an evaluation challenge for the cause of symptoms described as dizziness or instability. Some research agrees that in addition to evaluating vestibular function, physical examination should also assess the musculoskeletal system, as they are closely related to sarcopenia. Therefore, functional performance measures are becoming highly reliable and preferred indicators for assessing health and function in older adults, and evidence has been supporting their use as measures of change for years . Therefore, in our study, we used European Consensus tests such as the Short Physical Performance Battery (SPPB), the Timed Up and Go (TUG) test, and gait speed to measure these variables. These tests are not only indicative of sarcopenia but also assess balance and mobility, providing a comprehensive view of the patient’s physical state and their risk of falls and other adverse outcomes .
|
[
"Marina López-García",
"José Jesús Jiménez-Rejano",
"Carmen María Suárez-Serrano"
] |
https://doi.org/10.3390/jcm13144279
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999997 |
PMC11277823_p32
|
PMC11277823
|
sec[3]/p[2]
|
4. Discussion
| 3.865234 |
biomedical
|
Review
|
[
0.9970703125,
0.0008640289306640625,
0.0022983551025390625
] |
[
0.089111328125,
0.0042572021484375,
0.90625,
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The set of variables has been taken with reference tests and has broad support for its usefulness. Several studies have assessed the usefulness of the SPPB for evaluation with significant modifications through scheduled exercise for therapeutic purposes, as well as various exercise programs, and the conclusion is that it allows for showing changes and being sensitive to adverse effects such as hospital admissions and a predictor of falls, making it a useful measure even in the medium term . Furthermore, in the case of institutionalized settings, physical training alone does not seem to be sufficient to reduce and prevent falls, although there is controversy as to whether exercise improves more or not when supervised .
|
[
"Marina López-García",
"José Jesús Jiménez-Rejano",
"Carmen María Suárez-Serrano"
] |
https://doi.org/10.3390/jcm13144279
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999997 |
PMC11277823_p33
|
PMC11277823
|
sec[3]/p[3]
|
4. Discussion
| 4.089844 |
biomedical
|
Study
|
[
0.99951171875,
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0.0002510547637939453
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[
0.99853515625,
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0.0012664794921875,
0.00007301568984985352
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The studies conducted by Latham et al. with a population similar to our study (but with hip fracture and 6 months of follow-up) saw the clinically important difference on the SPPB scale was 0.3 to 0.8 points, and with respect to the moderate effect size of 0.4 (equivalent to moving from 6 to 7 on the score). These changes clearly determine the jump according to the test itself from a functionally higher type B to C. That is, to improve and go from moderate limitation or a frail patient (who presents with difficulty walking or with assistance, who gets up and completes balance tests with difficulty) to being a pre-frail patient (whose gait is already autonomous, although it retains gait disorders, with difficulty in doing five stand-ups and a subtle balance alteration) . In our study, both the ME and VE groups obtained scores exceeding this figure, which reaffirms us in the usefulness of the designed exercises. Other studies (conducted with a younger sample and composed of more individuals) point in the same direction, with a functional level situated at C, so the sensitivity margin is narrower , although it still marked a point as a limit . It sems that the inflection point is marked close to this point, with some authors establishing that a score of less than 8 implies severe mobility disability and even anticipate an 82% probability of developing falls in a 2-year follow-up.
|
[
"Marina López-García",
"José Jesús Jiménez-Rejano",
"Carmen María Suárez-Serrano"
] |
https://doi.org/10.3390/jcm13144279
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999996 |
PMC11277823_p34
|
PMC11277823
|
sec[3]/p[4]
|
4. Discussion
| 3.90625 |
biomedical
|
Review
|
[
0.9951171875,
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0.0032176971435546875
] |
[
0.017364501953125,
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] |
Studies have shown that telerehabilitation is effective for treating vestibular disorders, improving gait stability and balance during the COVID-19 pandemic. The systematic review made by Kundakci included individuals over 18 years old, not specifically older adults. These studies compared vestibular rehabilitation exercises to placebo or other interventions and concluded that the exercises improved balance capacity as per the finally selected articles. The findings of this research support the idea that vestibular telerehabilitation can be a useful strategy to improve balance and daily functionality in people with vestibular disorders, thus emphasizing its potential benefit in this specific area .
|
[
"Marina López-García",
"José Jesús Jiménez-Rejano",
"Carmen María Suárez-Serrano"
] |
https://doi.org/10.3390/jcm13144279
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999997 |
PMC11277823_p35
|
PMC11277823
|
sec[3]/p[5]
|
4. Discussion
| 3.955078 |
biomedical
|
Study
|
[
0.99951171875,
0.00036597251892089844,
0.0003223419189453125
] |
[
0.9775390625,
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This may indicate, as many authors comment, the need for complete and transdisciplinary work , although much progress is needed in the standardization of exercises and in evidence of their usefulness in reducing falls. Regarding the suitability of both techniques and their measurement according to TUG, our study has shown improvements in both groups, although there are authors who differentiate performing VE in subjects with reduced stability limits with great improvement and patients with more time in the TUG show worse results and can benefit more from gait training. In this sense, a systematic review also suggests that VR with exercises shows benefits for adult patients with chronic dizziness with respect to improvement in the vertigo symptom scale, risk of falls, and balance, without reaching an association like other authors with reductions of up to 50% in risk of falls with significant reductions in TUG. It may lead to the intervention period of only 6 weeks being understood as a limitation, even if they are daily sessions.
|
[
"Marina López-García",
"José Jesús Jiménez-Rejano",
"Carmen María Suárez-Serrano"
] |
https://doi.org/10.3390/jcm13144279
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999997 |
PMC11277823_p36
|
PMC11277823
|
sec[3]/p[6]
|
4. Discussion
| 4 |
biomedical
|
Study
|
[
0.9990234375,
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[
0.82080078125,
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Therefore, the interventions seem to indicate that they improve physical condition, although our study cannot infer a reduction in the risk of falls. Many authors find themselves in the same dilemma, justifying post-test improvements to the intervention in subacute contexts and even suggesting ultimately that exercise programs should be combined multicomponent (balance-coordination, strengthening and aerobic exercises) to improve balance, postural control, cognition, muscle strength, and quality of life and that specific programs for older adults involving moderate to high and challenging balance tasks could reduce the rate of falls. Perhaps the usefulness of technology-based programs can be suspected, but other authors already raised the degree of acceptance and adherence of older adults to technology-based exercise interventions, making a systematic review that included more than 20 studies in this population comparing traditional face-to-face programs with technology-based exercise programs, finding high adherence in both types of interventions (even adherence was higher in technology-based interventions, regardless of study location, level of supervision, and mode of delivery). As we pointed out in our study, and these authors also conclude, the exercise interventions were supervised. The review highlights that technology offers an acceptable way to provide older adults with attractive exercise opportunities, with high adherence rates in both supervised and unsupervised settings for at least the first 12 weeks of the intervention (considering that our intervention is 6 weeks although Vivifrail marks up to 12 weeks for the first re-evaluation). Another good point is that the average age range of the cohort was 67 to 86 years, similar to our study that was 69.55 to 82.67.
|
[
"Marina López-García",
"José Jesús Jiménez-Rejano",
"Carmen María Suárez-Serrano"
] |
https://doi.org/10.3390/jcm13144279
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999997 |
PMC11277823_p37
|
PMC11277823
|
sec[3]/p[7]
|
4. Discussion
| 3.617188 |
biomedical
|
Review
|
[
0.998046875,
0.0006051063537597656,
0.0014286041259765625
] |
[
0.12139892578125,
0.0127105712890625,
0.865234375,
0.0005145072937011719
] |
In the same line, other studies investigated the positive impact of visual stability and balance exercises through telerehabilitation in individuals with these disorders during the COVID-19 pandemic. These findings, aligned with the research of Harrell et al., suggested that vestibular telerehabilitation can be a useful strategy to improve balance and functionality in the daily life of people with vestibular disorders, highlighting its potential benefit in this area .
|
[
"Marina López-García",
"José Jesús Jiménez-Rejano",
"Carmen María Suárez-Serrano"
] |
https://doi.org/10.3390/jcm13144279
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999997 |
PMC11277823_p38
|
PMC11277823
|
sec[3]/p[8]
|
4. Discussion
| 2.759766 |
biomedical
|
Other
|
[
0.99169921875,
0.0031566619873046875,
0.005084991455078125
] |
[
0.0197601318359375,
0.97216796875,
0.00740814208984375,
0.0006718635559082031
] |
It is clear, therefore, that it is necessary to identify a patient profile whose improvement in balance directly influences the standardized tests by these new means and methods (and have proven to be useful in detecting frailty, and even fall risk), which are usually treated solely through multicomponent exercise.
|
[
"Marina López-García",
"José Jesús Jiménez-Rejano",
"Carmen María Suárez-Serrano"
] |
https://doi.org/10.3390/jcm13144279
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999998 |
PMC11277823_p39
|
PMC11277823
|
sec[3]/p[9]
|
4. Discussion
| 2.597656 |
biomedical
|
Study
|
[
0.99658203125,
0.0009765625,
0.0023345947265625
] |
[
0.99609375,
0.0032806396484375,
0.0003101825714111328,
0.0001518726348876953
] |
Limitations of the study: The difficulty in obtaining the sample to perform the number of daily sessions was a real challenge given the age and adherence presented by populations with these characteristics. Furthermore, we consider as another limitation of our study the impossibility of re-evaluating after 6 months to verify the permanence of the effects, due to the impact of COVID and the resulting restrictive measures, together with the unfortunate loss of the sample for a possible reassessment.
|
[
"Marina López-García",
"José Jesús Jiménez-Rejano",
"Carmen María Suárez-Serrano"
] |
https://doi.org/10.3390/jcm13144279
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999997 |
PMC11277823_p40
|
PMC11277823
|
sec[3]/p[10]
|
4. Discussion
| 2.144531 |
biomedical
|
Study
|
[
0.98583984375,
0.0010166168212890625,
0.01322174072265625
] |
[
0.9482421875,
0.047821044921875,
0.0035152435302734375,
0.0004673004150390625
] |
Additionally, as a limitation, it should be noted that the small sample size may affect the validity of the results due to potential heterogeneity.
|
[
"Marina López-García",
"José Jesús Jiménez-Rejano",
"Carmen María Suárez-Serrano"
] |
https://doi.org/10.3390/jcm13144279
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999998 |
PMC11277823_p41
|
PMC11277823
|
sec[4]/p[0]
|
5. Conclusions
| 2.488281 |
biomedical
|
Study
|
[
0.99755859375,
0.00090789794921875,
0.0016927719116210938
] |
[
0.93701171875,
0.05462646484375,
0.007411956787109375,
0.0007824897766113281
] |
There are indications of the efficacy of multicomponent exercise interventions and vestibular exercises to improve functional capacities measured according to SPPB through telerehabilitation, although vestibular physiotherapy does not demonstrate in this study to be superior in functional results to the control group.
|
[
"Marina López-García",
"José Jesús Jiménez-Rejano",
"Carmen María Suárez-Serrano"
] |
https://doi.org/10.3390/jcm13144279
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999996 |
PMC11277823_p42
|
PMC11277823
|
sec[4]/p[1]
|
5. Conclusions
| 3.007813 |
biomedical
|
Study
|
[
0.99755859375,
0.0006451606750488281,
0.0016031265258789062
] |
[
0.98876953125,
0.006320953369140625,
0.004627227783203125,
0.00021922588348388672
] |
Gait speed improves if multicomponent and vestibular exercises are performed, which are also home-based and mediated by technology. Both the vestibular exercise group and the multicomponent exercise group showed significant improvements in gait speed and dynamic balance in older adults through telerehabilitation. No significant differences were found between the two types of interventions in the measurements performed.
|
[
"Marina López-García",
"José Jesús Jiménez-Rejano",
"Carmen María Suárez-Serrano"
] |
https://doi.org/10.3390/jcm13144279
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999997 |
PMC11277823_p43
|
PMC11277823
|
sec[4]/p[2]
|
5. Conclusions
| 2.148438 |
biomedical
|
Other
|
[
0.9814453125,
0.0088958740234375,
0.009735107421875
] |
[
0.0025157928466796875,
0.9921875,
0.00446319580078125,
0.00091552734375
] |
Telerehabilitation is a viable and effective tool for functional improvement in older adults, facilitating adherence to exercise programs during situations such as the COVID-19 pandemic.
|
[
"Marina López-García",
"José Jesús Jiménez-Rejano",
"Carmen María Suárez-Serrano"
] |
https://doi.org/10.3390/jcm13144279
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999996 |
PMC11277823_p44
|
PMC11277823
|
sec[4]/p[3]
|
5. Conclusions
| 2.236328 |
biomedical
|
Other
|
[
0.97705078125,
0.001232147216796875,
0.0215606689453125
] |
[
0.1798095703125,
0.798828125,
0.020416259765625,
0.0009279251098632812
] |
According to the evidence, new studies are necessary that compare the effectiveness of a group that performs both interventions jointly against other scheduled exercises.
|
[
"Marina López-García",
"José Jesús Jiménez-Rejano",
"Carmen María Suárez-Serrano"
] |
https://doi.org/10.3390/jcm13144279
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999997 |
PMC11277838_p0
|
PMC11277838
|
sec[0]/p[0]
|
1. Introduction
| 4.0625 |
biomedical
|
Review
|
[
0.9755859375,
0.0175933837890625,
0.00698089599609375
] |
[
0.0025310516357421875,
0.0033283233642578125,
0.99365234375,
0.0006999969482421875
] |
Given the aging population and advancements in medical treatment and technology, the number of patients with heart failure (HF) is increasing across the world . HF is not only associated with high mortality rates and frequent hospitalizations; in recent years, it has also been linked to decline in physical ability and frailty. This leads not only to significant healthcare costs but also to increased need for care and burdens on living environments . Recently, novel HF drugs, often referred to as the “fantastic four”, have emerged and are expected to improve the prognosis of HF . However, in the treatment of HF, non-pharmacological treatments, especially self-care, are also considered important and strongly recommended in guidelines in Europe , the United States , and Japan . Self-care for patients with HF primarily includes adherence to prescribed medications, engagement in physical activity, management of fluid intake and monitoring of symptoms. There is a paucity of research on fluid management in patients with HF. Fluid restriction was traditionally considered a cornerstone of non-pharmacological management in HF patients. Some patients with HF are still advised to limit fluid intake in clinical practice. The rationale for this practice is based on the assumed reduction in body fluids, which could decrease congestion episodes. There is presumption that excessive fluid intake can be a contributing factor to decompensation for HF. However, this recommendation has largely been based on expert opinion. It remains unknown whether the evidence supports fluid restriction in patients with HF.
|
[
"Naoko P. Kato",
"Yuji Nagatomo",
"Fujimi Kawai",
"Takeshi Kitai",
"Atsushi Mizuno"
] |
https://doi.org/10.3390/jpm14070741
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999997 |
PMC11277838_p1
|
PMC11277838
|
sec[1]/p[0]
|
2. The History and Current State of Fluid Management and Sodium Control in Heart Failure
| 3.802734 |
biomedical
|
Review
|
[
0.99609375,
0.002597808837890625,
0.0011463165283203125
] |
[
0.017791748046875,
0.1973876953125,
0.78125,
0.003314971923828125
] |
The condition of fluid retention, historically known as “dropsy”, has been recognized since ancient times . Historically, the only treatments available were primitive methods, such as bloodletting and cupping, which physically reduce blood volume . In HF, the main issue is the excessive retention of extracellular fluid, and the advent of diuretics and the recognition of the diuretic effects of digitalis dramatically evolved treatment approaches. Realizing that kidney function plays a crucial role in fluid control constituted a significant advancement.
|
[
"Naoko P. Kato",
"Yuji Nagatomo",
"Fujimi Kawai",
"Takeshi Kitai",
"Atsushi Mizuno"
] |
https://doi.org/10.3390/jpm14070741
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999998 |
PMC11277838_p2
|
PMC11277838
|
sec[1]/p[1]
|
2. The History and Current State of Fluid Management and Sodium Control in Heart Failure
| 4.011719 |
biomedical
|
Review
|
[
0.9951171875,
0.0035343170166015625,
0.001186370849609375
] |
[
0.0234222412109375,
0.0584716796875,
0.91650390625,
0.0017452239990234375
] |
Since the 1950s, the development of medications with diuretic properties, particularly loop diuretics, has played a pivotal role in fluid management . These drugs, referred to as “diuretics”, primarily function to increase urine output, thereby promoting water excretion. However, it is crucial to note that the excretion of sodium (Na) plays a significant role in their mechanism of action, as it indirectly facilitates the removal of water. Managing sodium is closely linked to fluid management, and dietary sodium restriction has become an important strategy in the treatment and prevention of HF. Modern advancements have made it easier to control dietary salt intake compared to the past, but in clinical practice, it is more convenient to use macro-indicators such as body weight measurements and fluid volume checks.
|
[
"Naoko P. Kato",
"Yuji Nagatomo",
"Fujimi Kawai",
"Takeshi Kitai",
"Atsushi Mizuno"
] |
https://doi.org/10.3390/jpm14070741
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999996 |
PMC11277838_p3
|
PMC11277838
|
sec[1]/p[2]
|
2. The History and Current State of Fluid Management and Sodium Control in Heart Failure
| 4.136719 |
biomedical
|
Review
|
[
0.9951171875,
0.003681182861328125,
0.0012187957763671875
] |
[
0.053375244140625,
0.002117156982421875,
0.94384765625,
0.0008640289306640625
] |
However, in cases of acute HF, congestion and respiratory distress can occur even without an increase in body weight or a pure increase in body water, and the presence of water retention easily facilitates lung congestion due to increased venous return resulting in augmented cardiac preload. Therefore, managing fluids, weight, and sodium in patients with HF is crucial for preventing its onset and recurrence. In this context, appropriate restrictions on water and sodium intake are recommended. Historically, numerous studies have been conducted on fluid and sodium restriction, not being limited to the use of diuretics. However, loop diuretics, through their actions on the sodium/potassium/2–chloride co-transporter, lead to secretion of renin, with resulting neurohormonal activation . In this context, the opposite concept has emerged and the efficacy of fluid administration in ADHF has also been tested. The evidence on this strategy has been controversial and chaotic. The findings of some small studies have suggested the benefits of co-administration of small volumes of hypertonic saline . However, in observational studies, intravenous fluid administration was associated with worse in-hospital outcome . This paper focuses specifically on the clinical safety and efficacy of fluid restriction based on previous studies. We will discuss how fluid restriction is positioned within current treatment strategies and explore the scientific evidence supporting it .
|
[
"Naoko P. Kato",
"Yuji Nagatomo",
"Fujimi Kawai",
"Takeshi Kitai",
"Atsushi Mizuno"
] |
https://doi.org/10.3390/jpm14070741
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999997 |
PMC11277838_p4
|
PMC11277838
|
sec[2]/p[0]
|
3. Physiological Changes by Fluid Status in Heart Failure
| 4.671875 |
biomedical
|
Study
|
[
0.99853515625,
0.0011920928955078125,
0.0005106925964355469
] |
[
0.6962890625,
0.00189208984375,
0.300537109375,
0.0012483596801757812
] |
In the HF setting, the index event on heart function initiates the activation of compensatory mechanisms, including activation of the sympathetic nervous system (SNS) and the renin–angiotensin aldosterone system (RAAS), which are responsible for maintaining cardiac output through increased salt and water retention via reabsorption through the kidneys, peripheral arterial vasoconstriction, increased contractility, and inflammatory mediators that are responsible for mediating cardiac repair and remodeling. In the short term, these systems promote the restoration of cardiovascular function to a normal homeostatic range. However, sustained activation of these systems can lead to secondary end-organ damage in the heart, such as worsened left ventricular (LV) remodeling and subsequent cardiac decompensation. In this context, sodium and water restriction have been believed to be preventive against the promotion of this pathophysiology, since ingested sodium and water are completely absorbed through the intestine , irrespective of the presence or absence of HF . The physiological processes outlined above result in the retention of sodium and water in untreated HF patients. This retention serves as the foundation for dietary intake restriction recommendations. Indeed, in untreated pre-clinical HF patients, volume overload by acute saline load showed impaired natriuretic response, which was partially restored by exogeneous natriuretic peptide administration . However, the findings from animal experiments and human studies suggested that fluid restriction or sodium restriction can further promote the activation of the RAAS and the SNS. Moreover, these systems mutually activate each other and form a vicious cycle . This paradoxical activation of RAAS and SNS activity was also demonstrated in patients with HF .
|
[
"Naoko P. Kato",
"Yuji Nagatomo",
"Fujimi Kawai",
"Takeshi Kitai",
"Atsushi Mizuno"
] |
https://doi.org/10.3390/jpm14070741
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999996 |
PMC11277838_p5
|
PMC11277838
|
sec[2]/p[1]
|
3. Physiological Changes by Fluid Status in Heart Failure
| 4.085938 |
biomedical
|
Study
|
[
0.99951171875,
0.000583648681640625,
0.00012624263763427734
] |
[
0.99365234375,
0.0007452964782714844,
0.00518798828125,
0.0001742839813232422
] |
However, in stable HF patients treated with guideline-directed medical therapy (GDMT) such as renin–angiotensin system inhibitors (RASis), beta-blockers, and mineralocorticoid receptor antagonists (MRAs), the renal, hemodynamic, and neuroendocrine responses to alterations in sodium intake did not differ from those observed in healthy individuals . Therefore, it appears that the neuroendocrine mechanism responsible for sensing intravascular volume expansion might be preserved in patients with stable HF patients treated with GDMT. Additionally, strict dietary salt or water restriction is often associated with persistent thirst and reduced food intake . In this context, the effects of water restriction might be controversial in the HF setting.
|
[
"Naoko P. Kato",
"Yuji Nagatomo",
"Fujimi Kawai",
"Takeshi Kitai",
"Atsushi Mizuno"
] |
https://doi.org/10.3390/jpm14070741
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999997 |
PMC11277838_p6
|
PMC11277838
|
sec[3]/p[0]
|
4. Current Recommendation on Fluid Intake for Patients with Heart Failure
| 4.230469 |
biomedical
|
Review
|
[
0.9716796875,
0.0235595703125,
0.0045623779296875
] |
[
0.00606536865234375,
0.009124755859375,
0.9833984375,
0.0016202926635742188
] |
According to the textbook by Braunwald et al. , fluid restriction is generally unnecessary unless the patient is hyponatremic (<130 mEq/L), which may develop because of activation of the renin–angiotensin system, excessive secretion of arginine vasopressin, or loss of salt in excess of water from prior diuretic use. Fluid restriction (<2 L/day) is considered in hyponatremic patients (<130 mEq/L) or for those patients whose fluid retention is difficult to control despite high doses of diuretics and sodium restriction . The descriptions of fluid restriction in HF in the current guidelines are summarized in Table 1 . The recent HF guidelines from Japan and the Unites States of America do not address fluid intake recommendations. The guidelines issued by the European Society of Cardiology (ESC) advocate the avoidance of excessive fluid intake in all HF patients. In other words, recent HF guidelines recommend liberal fluid administration for both chronic and acute HF . Generally, normal fluid intake falls within the range of 1.5–2.5 L/day, corresponding to 15–30 mL/kg/day. In circumstances characterized by hot and humid weather conditions or gastrointestinal fluid loss, it is recommended to increase fluid intake to avoid dehydration . In the case of patients with severe HF or hyponatremia, a fluid restriction of 1–1.5 L/day may be considered to relieve symptoms and congestion . Fluid restriction may assist in managing sodium levels in cases of acute decompensated HF (ADHF) patients with dilutional hyponatremia. However, findings from a registry study of acute decompensated HF patients with hyponatremia (the HN Registry) indicate that fluid restriction was the least effective approach for correcting hyponatremia. In Japan, Tolvaptan, a vasopressin type 2 receptor antagonist, has been approved since 2010 for HF patients with volume overload and who are refractory to other conventional diuretic therapies, regardless of the presence of hyponatremia. When employing Tolvaptan treatment for patients with hyponatremia, a liberal fluid intake approach is typically used.
|
[
"Naoko P. Kato",
"Yuji Nagatomo",
"Fujimi Kawai",
"Takeshi Kitai",
"Atsushi Mizuno"
] |
https://doi.org/10.3390/jpm14070741
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999997 |
PMC11277838_p7
|
PMC11277838
|
sec[4]/p[0]
|
5. Challenges and Implications of Fluid Management for Patients with Heart Failure
| 4.007813 |
biomedical
|
Review
|
[
0.99755859375,
0.0015745162963867188,
0.0010423660278320312
] |
[
0.0635986328125,
0.0019683837890625,
0.93408203125,
0.00044536590576171875
] |
Previously, it was mentioned that the activation of compensatory mechanisms, including the SNS and the RAAS, alters fluid metabolism in HF patients. However, in stable HF patients treated with GDMT, the neuroendocrine mechanisms for sensing intravascular volume expansion are preserved. Yet in real clinical practice, accurately monitoring intravascular volume is challenging. Various methods, such as chest X-ray, echocardiographic volume measurements, IVC ultrasound, lung ultrasound, and bioimpedance analysis, have been used to assess fluid composition in subjects, including HF patients . Nevertheless, there is no single most-reliable indicator in clinical practice, and self-care monitoring still often relies on body weight as a surrogate marker . In practical recommendations, total fluid volume is often specified for water restriction. However, how these fluids are absorbed and distributed into intravascular and extravascular spaces is unknown. Further research on fluid monitoring using innovative digital devices is anticipated, but for now it remains challenging to regulate appropriate fluid volumes in an aging HF population.
|
[
"Naoko P. Kato",
"Yuji Nagatomo",
"Fujimi Kawai",
"Takeshi Kitai",
"Atsushi Mizuno"
] |
https://doi.org/10.3390/jpm14070741
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999997 |
PMC11277838_p8
|
PMC11277838
|
sec[4]/p[1]
|
5. Challenges and Implications of Fluid Management for Patients with Heart Failure
| 4.082031 |
biomedical
|
Review
|
[
0.986328125,
0.0121917724609375,
0.0014238357543945312
] |
[
0.0286712646484375,
0.029876708984375,
0.939453125,
0.0018529891967773438
] |
Not only is fluid monitoring difficult, but fluid restriction can also impact a patient’s quality of life. Several studies have shown that fluid restriction is a risk factor for increased thirst distress in patients with HF . In addition, it is challenging for HF patients to follow fluid restrictions due to a lack of knowledge about the liquid content of different foods and the management of co-morbidities such as kidney diseases . It has been reported that maintaining fluid restriction can be difficult for some HF patients due to their habitual behavior of consuming water with meals. HF patients sometimes have difficulty monitoring daily fluid intake and adjusting fluid intake. Not all patients can adjust their fluid intake based on climatic conditions such as high heat and humidity, or in case of fluid loss, due to nausea and vomiting, for example. Some patients may adhere to fluid restriction even in very hot conditions, leading to dehydration. This is especially common among elderly patients. Moreover, excessive fluid restriction, when combined with diuretic use, can result in dehydration, heightened thirst sensation, and impaired quality of life . Thus, for implementation of fluid restriction, education, support, and planned evaluation are essential. To ensure successful fluid management in patients with HF, it is crucial not only to address the quantity of fluid intake but also to discuss dietary habits, climatic conditions, and diuretic treatment.
|
[
"Naoko P. Kato",
"Yuji Nagatomo",
"Fujimi Kawai",
"Takeshi Kitai",
"Atsushi Mizuno"
] |
https://doi.org/10.3390/jpm14070741
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999997 |
PMC11277838_p9
|
PMC11277838
|
sec[5]/sec[0]/p[0]
|
6.1. Studies in Acute Decompensated Heart Failure
| 3.914063 |
biomedical
|
Review
|
[
0.99755859375,
0.002017974853515625,
0.0003998279571533203
] |
[
0.278564453125,
0.049102783203125,
0.67041015625,
0.00185394287109375
] |
In the ADHF setting, the treatment goal is achievement of hemodynamic stability and symptomatic improvement. For this aim, fluid restriction may appear to be a logical intervention. Indeed, it had been traditionally believed to be beneficial and frequently applied to expedite recovery in the management of ADHF . On the other hand, it could be argued that fluid restriction in the setting of intravenous diuretic use could predispose patients to an adverse outcome in certain circumstances, possibly due to the resultant activation of the renin–angiotensin–aldosterone system . Nonetheless, data that could be used to examine this issue are very sparse.
|
[
"Naoko P. Kato",
"Yuji Nagatomo",
"Fujimi Kawai",
"Takeshi Kitai",
"Atsushi Mizuno"
] |
https://doi.org/10.3390/jpm14070741
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999997 |
PMC11277838_p10
|
PMC11277838
|
sec[5]/sec[0]/p[1]
|
6.1. Studies in Acute Decompensated Heart Failure
| 4.1875 |
biomedical
|
Study
|
[
0.95751953125,
0.04156494140625,
0.0009684562683105469
] |
[
0.9453125,
0.04388427734375,
0.00772857666015625,
0.0031719207763671875
] |
Aliti et al. randomized 75 patients to either restricted fluid (<800 mL/day) and sodium (<800 mg/day) intake or liberal fluid and sodium intake (>2.5 L/day and 3–5 g/day, respectively). Weight loss and change in clinical congestion score were similar between both groups. Thirst was significantly worse in the fluid and Na restriction group. Readmission rates at 30 days were also similar. No significant differences were observed between the two groups in terms of intravenous diuretic administration rates, weight changes, or clinical stability during the 3-day follow-up period. Applying a similar approach but concentrating solely on fluid restriction, Travers et al. randomized 67 patients with ADHF within 24 h of admission to either fluid restriction (<1 L/day) or free fluid intake. They observed no significant difference in the time to clinical stabilization between the two groups. Changes from baseline to achievement of clinical stability in serum urea, serum creatinine, B-type natriuretic peptides (BNPs), and sodium did not differ between the two groups. However, the between-group difference in fluid intake was only 400 mL/day .
|
[
"Naoko P. Kato",
"Yuji Nagatomo",
"Fujimi Kawai",
"Takeshi Kitai",
"Atsushi Mizuno"
] |
https://doi.org/10.3390/jpm14070741
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999997 |
PMC11277838_p11
|
PMC11277838
|
sec[5]/sec[0]/p[2]
|
6.1. Studies in Acute Decompensated Heart Failure
| 4.089844 |
biomedical
|
Study
|
[
0.9453125,
0.05340576171875,
0.0011491775512695312
] |
[
0.896484375,
0.09100341796875,
0.00875091552734375,
0.0036067962646484375
] |
Albert et al. randomized 46 patients with ADHF and hyponatremia (<135 mmol/L) to 1000 mL/day fluid restriction and usual care at discharge. There were no significant differences in clinical endpoints such as all-cause death, emergency care visits due to HF, or HF rehospitalization. However, the fluid restriction group showed a more favorable quality of life, including symptoms related to HF. Thus, for patients concomitant with hyponatremia, fluid restriction may be beneficial in terms of symptom relief.
|
[
"Naoko P. Kato",
"Yuji Nagatomo",
"Fujimi Kawai",
"Takeshi Kitai",
"Atsushi Mizuno"
] |
https://doi.org/10.3390/jpm14070741
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999996 |
PMC11277838_p12
|
PMC11277838
|
sec[5]/sec[0]/p[3]
|
6.1. Studies in Acute Decompensated Heart Failure
| 2.476563 |
biomedical
|
Other
|
[
0.9931640625,
0.004886627197265625,
0.0018548965454101562
] |
[
0.005283355712890625,
0.978515625,
0.0139312744140625,
0.002216339111328125
] |
Fluid restriction commonly causes thirst in healthy subjects and ADHF patients , even in cases of hyponatremia , and significantly and negatively impacts quality of life. Xerostomia, altered taste, dry skin, and itching are also seen as side effects in fluid restriction.
|
[
"Naoko P. Kato",
"Yuji Nagatomo",
"Fujimi Kawai",
"Takeshi Kitai",
"Atsushi Mizuno"
] |
https://doi.org/10.3390/jpm14070741
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999997 |
PMC11277838_p13
|
PMC11277838
|
sec[5]/sec[1]/p[0]
|
6.2. Studies in Compensated Heart Failure
| 3.837891 |
biomedical
|
Review
|
[
0.998046875,
0.001308441162109375,
0.0008630752563476562
] |
[
0.083740234375,
0.0022125244140625,
0.91357421875,
0.0004425048828125
] |
There have been only two randomized controlled trials conducted to evaluate the benefits of fluid restriction alone in patients with compensated HF . Several studies have investigated the impacts of combined dietary interventions involving fluid and sodium restriction or cardiac rehabilitation, emphasizing adherence to diet, physical activity, and fluid restriction . The degree of fluid restriction in these interventions varied among studies, with common amounts being 1000 mL and 1500 mL/day.
|
[
"Naoko P. Kato",
"Yuji Nagatomo",
"Fujimi Kawai",
"Takeshi Kitai",
"Atsushi Mizuno"
] |
https://doi.org/10.3390/jpm14070741
|
N/A
|
https://creativecommons.org/licenses/by/4.0/
|
en
| 0.999994 |
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