The objective of this study is to combine troponin and indicators of cardiac acoustics for synthetically evaluating cardiac fatigue of rabbits, analyzing exercise-induced cardiac fatigue (EICF) and exercise-induced cardiac damage (EICD). New Zealand white rabbits were used to conduct a multi-step swimming experiments with load, reaching an exhaustive state for evaluating if the amplitude ratio of the first to second heart sound (S1/S2) and heart rate (HR) during the exhaustive exercise would decrease or not and if they would be recovered 24-48 h after exhaustive exercise. The experimental end point was to complete 3 times of exhaustions or death from exhaustion. Circulating troponin I (cTnI) were detected from all of the experimental rabbits at rest [(0.02±0.01) ng/mL], which, in general, indicated that there existed a physiological release of troponin. After the first exhaustive swim, cTnI of the rabbits increased. However, with 24-hour rest, S1/S2, HR, and cTnI of the tested rabbits all returned toward baseline levels, which meant that the experimental rabbits experienced a cardiac fatigue process. After repeated exhaustion, overloading phenomena were observed, which led to death in 3 out of 11 rabbits, indicating their cardiac damage; the troponin elevation under this condition could be interpreted by pathological release. Evaluation of myocardial damage can not be based on the troponin levels alone, but can only be based on a comprehensive analysis.
In order to evaluate the safety performance of self-expandable NiTi alloy stents systematically, the dynamic safety factor drawn up by International Organization for Standardization, was used to quantitatively reflect the safety performance of stents. Based on the constitutive model of super-elastic memory alloy material in Abaqus and uniaxial tensile test data of NiTi alloy tube, finite element method and experiments on accelerated fatigue life were carried out to simulate the self-expansion process and the shape change process under the action of high and low blood pressure for three L-type stents of Φ8×30 mm, Φ10×30 mm, Φ12×30 mm. By analyzing the changes of stress and strain of self-expanding NiTi alloy stent, the maximum stress and strain, stress concentration position, fatigue strength and possible failure modes were studied, thus the dynamic safety factor of stent was calculated. The results showed that the maximum stress and plastic strain of the stent increased with the increase of grip pressure, but the maximum stress and strain distribution area of the stent had no significant change, which were all concentrated in the inner arc between the support and the connector. The dynamic safety factors of the three stents were 1.31, 1.23 and 1.14, respectively, which indicates that the three stents have better safety and reliability, and can meet the fatigue life requirements of more than 10 years, and safety performance of the three stents decreases with the increase of stent’s original diameter.
ObjectiveTo systematically review the clinical features of chronic fatigue syndrome (CFS) cases with pathogens infection.
MethodsWe electronically searched databases including VIP, WanFang Data, CNKI, CBM, PubMed, MEDLINE, EMbase, The Cochrane Library, Web of Science, Elsevier and Google Scholar from 1994 to 2014 for CFS-related studies. Two reviewers independently screened literature and extracted data. Then we systematically reviewed and analyzed the information on demographic characteristics, clinical manifestations, types of infected pathogens, and results of some biochemical examinations.
ResultsA total of 84 studies (case reports and case series) involving 2 565 CFS cases from 18 countries were included. The major infected pathogens of included CFS cases were mycoplasma, EB virus, intestinal virus, Bernat rickettsia, human-herpes virus, and Gram-negative intestinal bacteria. Fifty-seven studies reported that there might be associations between the pathogenic infection and CFS pathogenesis. Although there were different types of CFS-related pathogens, almost all the studies inferred that pathogens infection linked with immune dysfunction, which might cause CFS symptoms.
ConclusionThere may be associations between the pathogenic infection and CFS pathogenesis.
Total hip replacement (THR) is replacing the prosthesis stem similar to human bone that takes advantage of the material with both good mechanical properties and biocompatibility to the damaged articular surface. Thus it can not only alleviate or even eliminate the pain but also effectively maintain the joint stability and freedom and restore its normal performance. Finite element analysis was used in this study to establish a 3D model of artificial hip stem, and explore its fatigue properties of different materials to ensure the safety and reliability. The calculating obtained two results of different metal hip prosthesis, including lifetime and deformation. The minimum service life of titanium prosthesis reaches 568 million times, which satisfies ISO standards, while the stainless steel does not suit to be a prosthesis material.
Exercise-induced muscle fatigue is a phenomenon that the maximum voluntary contraction force or power output of muscle is temporarily reduced due to muscular movement. If the fatigue is not treated properly, it will bring about a severe injury to the human body. With multi-channel collection of lower limb surface electromyography signals, this article analyzes the muscle fatigue by adoption of band spectrum entropy method which combined electromyographic signal spectral analysis and nonlinear dynamics. The experimental result indicated that with the increase of muscle fatigue, muscle signal spectrum began to move to low frequency, the energy concentrated, the system complexity came down, and the band spectrum entropy which reflected the complexity was also reduced. By monitoring the entropy, we can measure the degree of muscle fatigue, and provide an indicator to judge fatigue degree for the sports training and clinical rehabilitation training.
ObjectivesTo systematically review the risk factors of acute fatigue in patients with stroke.MethodsPubMed, Web of Science, EMbase, The Cochrane Library, CNKI, VIP and WanFang Data databases were electronically searched to collect case-control studies, cohort studies and cross-sectional studies on the risk factors of acute fatigue in patients with stroke from inception to April, 2019. Two reviewers independently screened literature, extracted data and assessed risk of bias of included studies, then, meta-analysis was performed by using RevMan 5.3 software.ResultsA total of 14 studies involving 2 658 objects and 13 risk factors were included. The results of meta-analysis showed that: female (OR=1.54, 95%CI 1.23 to 1.94, P=0.000 2), rural residence (OR=1.46, 95%CI 1.11 to 1.91, P=0.007), diabetes mellitus (OR=1.54, 95%CI 1.24 to 1.92, P<0.000 1), hyperlipidemia (OR=1.41, 95%CI 1.10 to 1.80, P=0.007), coronary heart disease (OR=1.94, 95%CI 1.30 to 2.89, P=0.001), previous stroke history (OR=1.54, 95%CI 1.07 to 2.23, P<0.000 01), pre-stroke fatigue (OR=4.51, 95%CI 3.33 to 6.09, P<0.000 01), basal ganglia stroke (OR=2.76, 95%CI 1.21 to 6.29, P<0.000 01), NIHSS >3 (OR=2.11, 95%CI 1.59 to 2.79, P<0.000 01), admission glucose level (OR=1.08, 95%CI 0.38 to 1.78, P=0.003), post-stroke sleep disorder (OR=2.40, 95%CI 1.87 to 3.07, P<0.000 01), post-stroke pain (OR=2.32, 95%CI 1.56 to 3.45, P<0.000 1) and post-stroke depression (OR=3.31, 95%CI 1.94 to 5.66, P<0.000 1) were risk factors of acute fatigue in patients with stroke.ConclusionsCurrent evidence shows that female, rural residence, diabetes mellitus, hyperlipidemia, coronary heart disease, previous stroke history, pre-stroke fatigue, basal ganglia stroke, NIHSS>3, admission glucose level, post-stroke sleep disorder, post-stroke pain and post-stroke depression are the risk factors of acute fatigue in patients with stroke. Medical staff should strengthen targeted preventive care for high-risk patients with related risk factors in order to reduce the incidence of post-stroke fatigue and improve the clinical prognosis outcome of patients.
The purpose of this study is to compare the differences among neck muscle fatigue evaluation algorithms and to find a more effective algorithm which can provide a human factor quantitative evaluation method for neck muscle fatigue during bending over the desk. We collected surface electromyography signal of sternocleidomastoid muscle of 15 subjects using wireless physiotherapy Bio-Radio when they bent over the desk using memory pillows for 12 minutes. Five algorithms including mean power frequency, spectral moments ratio, discrete wavelet transform, fuzzy approximation entropy and the complexity algorithms were used to calculate the corresponding muscle fatigue index. The least squares method was used to calculate the corresponding coefficient of determination R2 and slope k of the linear regression of the muscle fatigue metric. The coefficient of determination R2 evaluates anti-interference ability of algorithms. The maximum vertical distance Lmax which is obtained by the Kolmogorov-Smirnov test for the slopes k evaluates the ability to distinguish fatigue of algorithms. The results indicate that in the aspect of anti-interference ability, the fuzzy approximation entropy has the largest R2 when using memory pillows with different heights. When the fuzzy approximate entropy is compared with average power frequency or the discrete wavelet transform, the differences are significant (P < 0.05). In terms of distinguishing the degree of fatigue, the approximate entropy is still the largest, with a maximum of 0.496 7. Fuzzy approximation entropy is superior to other algorithms in ability of anti-interference and distinguishing fatigue. Therefore, fuzzy approximation entropy can be used as a better evaluation algorithm in the evaluation of cervical muscle fatigue.
In the present paper, the contribution of the largest principal component and the number of principal component needed for accumulative contribution 95% are selected as indices of electroencephalogram (EEG) in mental fatigue state in order to investigate the relationship between these parameters and mental fatigue. The experimental results showed that the contribution of the largest principal component of EEG signals increased in the prefrontal, frontal and central areas, while the number of principal component needed for accumulative contribution decreased by 95% with the increasing mental fatigue level. The parameters of singular system of EEG signals can be regarded as useful features for the estimation of mental fatigue and have larger application value in the study of mental fatigue.
Inflammatory bowel disease (IBD) is characterized by recurrent abdominal pain, diarrhea, and mucopurulent bloody stools as its main clinical manifestations. In recent years, its parenteral manifestations have received increasing attention. Fatigue, as one of the extraintestinal manifestations of IBD, affects the quality of life of patients, and results in considerable distress for patients. The influencing factors of fatigue symptoms in IBD patients include inflammation, psychological comorbidities, sleep disorders, anemia, micronutrient deficiency, changes in microbiota, and metabolomics. The pathogenesis is currently unclear and may be related to disorders in tryptophan metabolism. This article will review the influencing factors and pathogenesis of fatigue symptoms in IBD patients, aiming to provide a basis for the prevention and treatment of IBD fatigue.
With the wide application of virtual reality technology and the rapid popularization of virtual reality devices, the problem of brain fatigue caused by prolonged use has attracted wide attention. Sixteen healthy subjects were selected in this study. And electroencephalogram (EEG) signals were acquired synchronously while the subjects watch videos in similar types presented by traditional displayer and virtual reality separately. Two questionnaires were conducted by all subjects to evaluate the state of fatigue before and after the experiment. The mutual correlation method was selected to construct the mutual correlation brain network of EEG signals before and after watching videos in two modes. We also calculated the mutual correlation coefficient matrix and the mutual correlation binary matrix and compared the average of degree, clustering coefficient, path length, global efficiency and small world attribute during two experiments. The results showed that the subjects were easier to get fatigue by watching virtual reality video than watching video presented by traditional displayer in a certain period of time. By comparing the characteristic parameters of brain network before and after watching videos, it was found that the average degree value, the average clustering coefficient, the average global efficiency and the small world attribute decreases while the average path length value increased significantly. In addition, compared to traditional plane video, the characteristic parameters of brain network changed more greatly after watching the virtual reality video with a significant difference (P < 0.05). This study can provide theoretical basis and experimental reference for analyzing and evaluating brain fatigue induced by virtual reality visual experience.
