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Query: UMLS:C0015672 (fatigue)
 51,768 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Ultra high molecular weight polyethylene (UHMWPE) has been used in artificial joints for a few decades, and wear of UHMWPE has been one of the main problems. Though many other materials have been tested over the years, the best clinical results are still achieved with UHMWPE. This makes the study of UHMWPE, especially in relation to artificial joints, very important. Frequently, more severe wear can be observed in artificial knee joints than in artificial hip joints especially when the flaking-like wear occurs. This flaking-like wear can lead to significant destruction of the artificial knee joint. Macroscopically, artificial knee joints have combinational movements of rolling and sliding in order to simulate the motion of the normal knee joint. The components of motion are separated to make study easier. Fatigue tests of UHMWPE under the rolling contact condition were performed in this study. Three ceramic spheres were rolled over the UHMWPE specimen using 37 degrees C distilled water as a lubricant. The UHMWPE specimen was observed by the scanning acoustic tomography, microscopy, and SEM. Some subsurface defects could be observed by SAT even before experiments. Although the apparent wear is not observed on the surface, there was an increase in the number of observable subsurface cracks in the UHMWPE specimen. This shows that cracks occur under the surface after a 10(7) rolling contact loading, which is very close to the cyclic loading and unloading with very little friction compared to the sliding contact.
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PMID:An observation on subsurface defects of ultra high molecular weight polyethylene due to rolling contact. 913 54

In order to verify the frequency of human brucellosis among a TB suspected population, a study was conducted on the basis of sero-diagnosis of a total of 229 blood samples from TB suspected patients. Serological tests carried out were slide and semi-quantitative agglutination tests. Of the tested samples, 44 (19.21%) were SAT positive and of these, 28 (12.23%) were positive for the semiquantitative agglutination test. Twelve (42.86%) had a brucella titer of 1:80; 14 (50%) had a brucella titer of 1:160 and 2 (7.14%) had a titer of 1:320. The majority of patients positive for brucellosis, exhibiting sero-agglutination titers ranging between 1:40 and 1:320, were of rural background. However, 35.72% persons positive for brucella antibody with titer of 1:160 were from urban localities. Fever (84.48%), headache/dizziness (71.43%) and weakness/fatigue (46.43%) were the most common presenting symptoms among the brucellosis positive patients. The frequency of brucellosis among these TB suspected patients was found to be higher in women (73.91%), as compared to men (52.38%).
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PMID:Sero-diagnosis of human brucellosis among TB suspected patients. 952 48

Saturated and unsaturated fatty acid supplements (FS) were evaluated for effects on yield of milk and milk components, concentration of milk components including milk fatty acid profile, and energy balance. Eight ruminally and duodenally cannulated cows and 8 noncannulated cows were used in a replicated 4 x 4 Latin square design experiment with 21-d periods. Treatments were control and a linear substitution of 2.5% fatty acids from saturated FS (SAT; prilled, hydrogenated free fatty acids) for partially unsaturated FS (UNS; calcium soaps of long-chain fatty acids). The SAT treatment did not change milk fat concentration, but UNS linearly decreased milk fat in cannulated cows and tended to decrease milk fat in noncannulated cows compared with control. Milk fat depression with UNS corresponded to increased concentrations of trans-10, cis-12 conjugated linoleic acid and trans C18:1 fatty acids in milk. Milk fat profile was similar for SAT and control, but UNS decreased concentration of short- and medium-chain FA. Digestible energy intake tended to decrease linearly with increasing unsaturated FS in cannulated and noncannulated cows. Increasing unsaturated FS linearly increased empty body weight and net energy gain in cannulated cows, whereas increasing saturated FS linearly increased plasma insulin. Efficiency of conversion of digestible energy to milk tended to decrease linearly with increasing unsaturated FS for cannulated cows only. Addition of SAT provided little benefit to production and energy balance, whereas UNS decreased energy intake and milk energy yield.
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PMID:Effects of fatty acid supplements on milk yield and energy balance of lactating dairy cows. 1650 5

The present study aimed to investigate the relationship between subjective fatigue and selective attention deficits following traumatic brain injury (TBI). Forty-six participants with mild-severe TBI and 46 healthy controls completed fatigue scales (Visual Analogue Scale--Fatigue, Fatigue Severity Scale [FSS] and Causes of Fatigue Questionnaire [COF]), and attentional measures including subtests from the Test of Everyday Attention, and the Complex Selective Attention Task (C-SAT). TBI participants reported greater fatigue on the FSS and COF, performed more slowly on attentional measures, and made more errors on the C-SAT. After controlling for anxiety and depression, fatigue was significantly correlated with performance only on the C-SAT. Findings suggest a relationship between subjective fatigue and impairment on tasks requiring higher order attentional processes.
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PMID:Selective attention deficits and subjective fatigue following traumatic brain injury. 1671 31

Person and situational determinants of cognitive ability test performance and subjective reactions were examined in the context of tests with different time-on-task requirements. Two hundred thirty-nine first-year university students participated in a within-participant experiment, with completely counterbalanced treatment conditions and test forms. Participants completed three test sessions of different length: (a) a standard-length SAT test battery (total time 4(1/2) hr), (b) a shorter SAT test battery (total time 3(1/2) hr), and (c) a longer SAT test battery (total time 5(1/2) hr). Consistent with expectations, subjective fatigue increased with increasing time-on-task. However, mean performance increased in the longer test length conditions, compared with the shorter test length condition. Individual differences in personality/interest/motivation trait complexes were found to have greater power than the test-length situations for predicting subjective cognitive fatigue before, during, and at the end of each test session. The relative contributions of traits and time-on-task for cognitive fatigue are discussed, along with implications for research and practice. (PsycINFO Database Record (c) 2009 APA, all rights reserved).
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PMID:Test length and cognitive fatigue: an empirical examination of effects on performance and test-taker reactions. 1958 55

Brucellosis is considered the most widespread zoonosis in the world. In endemic regions of brucellosis, childhood brucellosis includes up to one-third of all cases of human brucellosis. Brucellosis constitutes a public health problem in Turkey. A boy aged 12 yr who had PFIC2 had undergone deceased-donor liver transplantation in 2008 at the age of seven. The boy presented with fatigue, fever, and pain in the right leg and hip and was admitted to the hospital. Brucella melitensis grew in the blood culture, and the SAT was positive at a titer of 1:640. The patient was treated with oral doxycycline and rifampicin for eight wk. After treatment, the patient recovered and his blood cultures became negative. The patient's mother also had a high Brucella agglutination titer of 1:320 positive and was treated in the internal medicine department with spiramycin and doxycycline. Brucella infection should be suspected in liver transplant recipients with fever of unknown origin, especially in recipients who live in an endemic area.
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PMID:Brucella infection in a child with progressive familial intrahepatic cholestasis type 2 who had undergone liver transplantation. 2614 81

This paper presents an adaptive system intended to address workload imbalances between pilots in future flight decks. Team performance can be maximized when task demands are balanced within crew capabilities and resources. Good communication skills enable teams to adapt to changes in workload, and include the balancing of workload between team members This work addresses human factors priorities in the aviation domain with the goal to develop concepts that balance operator workload, support future operator roles and responsibilities, and support new task requirements, while allowing operators to focus on the most safety critical tasks. A traditional closed-loop adaptive system includes the decision logic to turn automated adaptations on and off. This work takes a novel approach of replacing the decision logic, normally performed by the automation, with human decisions. The Crew Workload Manager (CWLM) was developed to objectively display the workload between pilots and recommend task sharing; it is then the pilots who "close the loop" by deciding how to best mitigate unbalanced workload. The workload was manipulated by the Shared Aviation Task Battery (SAT-B), which was developed to provide opportunities for pilots to mitigate imbalances in workload between crew members. Participants were put in situations of high and low workload (i.e., workload was manipulated as opposed to being measured), the workload was then displayed to pilots, and pilots were allowed to decide how to mitigate the situation. An evaluation was performed that utilized the SAT-B to manipulate workload and create workload imbalances. Overall, the CWLM reduced the time spent in unbalanced workload and improved the crew coordination in task sharing while not negatively impacting concurrent task performance. Balancing workload has the potential to improve crew resource management and task performance over time, and reduce errors and fatigue. Paired with a real-time workload measurement system, the CWLM could help teams manage their own task load distribution.
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PMID:Evaluation of the Display of Cognitive State Feedback to Drive Adaptive Task Sharing. 2840 Jul 16

MS related fatigue might be related to autonomous nervous system (ANS) dysfunctions or to inflammation related vagal (hyper-) activation. Consequently, influencing ANS status may lead to relieve of fatigue. We used two opposite biofeedback interventions to either increase sympathetic ("self-alert training", SAT) or parasympathetic activation ("progressive muscle relaxation", PMR). We recorded fatigue status of patients before and after a challenging vigilance task, their behavioural performance on this task, their skin conductance response (SCR), and parameters indicating parasympathetic activity concerning heart rate variability (HRV). We repeated these recordings after the biofeedback training sessions. Patients of the SAT group were able to learn to increase their SCR voluntarily. Patients of the PMR group showed increasing parameters indicating parasympathetic modulation of the HRV. The vigilance task increased their feeling of fatigue. However, there was no effect of biofeedback training on either fatigue status or performance on the vigilance task. Our results show that MS patients can learn to change voluntarily their ANS activity using biofeedback instructions based on SCR and this can be used in future studies to test the postulated link between ANS and fatigue. However, in this experimental intervention we were unable to document a relation between ANS activity and fatigue. Trial registration: ClinicalTrials.gov identifier: NCT03268187.
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PMID:Can biofeedback-based training alleviate fatigue and vigilance performance in fatigued MS patients? 3285 96