A Large-Scale European Union Study of Aircrew Fatigue During Long Night and Disruptive Duties

INTRODUCTION: We examined aircrew fatigue during the following flight duty periods (FDPs) mentioned in the European Union (EU) Flight Time Limitations (FTLs): night FDPs longer than 10 h and FDPs typical of disruptive schedules (early starts, late finishes, and nights). An alternative way of classifying night FDPs was also examined to reveal possible subcategories that warrant special attention.METHODS: A total of 392 aircrew members (96 women) representing 24 airlines participated in the study. Their FDPs were measured by a diary, sleep by the diary and wrist-actigraphy, and fatigue by the Karolinska Sleepiness Scale (KSS) over 14 consecutive days. The KSS ratings given at top of descent (TOD) served as the main outcome.RESULTS: The probability of high fatigue (KSS ≥ 7) at TOD was 0.41 and 0.32 during long (>10 h) and short night (≤10 h) FDPs, respectively. The corresponding value was 0.19 for early starts, 0.31 for late finishes, 0.34 for night FDPs, and 0.15 for day FDPs (reference). The main predictors of high fatigue were FDP's encroachment on the window of circadian low (WOCL, 02:00 h-05:59 h) and prior sleep. Within the night category, FDPs fully covering the WOCL showed the highest probability of high fatigue at TOD (0.42).DISCUSSION: Late finish and night FDPs warrant special attention in fatigue management. Within the night category, the same holds for FDPs that fully cover the WOCL. To manage fatigue, adjustments of the FTLs seem to be a limited strategy and therefore other measures, including maximizing preflight sleep, are needed.Sallinen M, van Dijk H, Aeschbach D, Maij A, Åkerstedt T. A large-scale European Union study of aircrew fatigue during long night and disruptive duties. Aerosp Med Hum Perform. 2020; 91(8):628-635.

Deciphering the complex nature of bolting time regulation in Beta vulgaris

Only few genetic loci are sufficient to increase the variation of bolting time in Beta vulgaris dramatically, regarding vernalization requirement, seasonal bolting time and reproduction type. Beta species show a wide variation of bolting time regarding the year of first reproduction, seasonal bolting time and the number of reproduction cycles. To elucidate the genetics of bolting time control, we used three F₃ mapping populations that were produced by crossing a semelparous, annual sugar beet with iteroparous, vernalization-requiring wild beet genotypes. The semelparous plants died after reproduction, whereas iteroparous plants reproduced at least twice. All populations segregated for vernalization requirement, seasonal bolting time and the number of reproduction cycles. We found that vernalization requirement co-segregated with the bolting locus B on chromosome 2 and was inherited independently from semel- or iteroparous reproduction. Furthermore, we found that seasonal bolting time is a highly heritable trait (h ² > 0.84), which is primarily controlled by two major QTL located on chromosome 4 and 9. Late bolting alleles of both loci act in a partially recessive manner and were identified in both iteroparous pollinators. We observed an additive interaction of both loci for bolting delay. The QTL region on chromosome 4 encompasses the floral promoter gene BvFT2, whereas the QTL on chromosome 9 co-localizes with the BR ₁ locus, which controls post-winter bolting resistance. Our findings are applicable for marker-assisted sugar beet breeding regarding early bolting to accelerate generation cycles and late bolting to develop bolting-resistant spring and winter beets. Unexpectedly, one population segregated also for dwarf growth that was found to be controlled by a single locus on chromosome 9.

Individual Human Serum Differs in the Amount of Antibodies with Affinity for Pig Fetal Ventral Mesencephalic Cells and the Ability to Lyse These Cells by Complement Activation

Xenografting pig fetal ventral mesencephalic (pfVM) cells to repair the dopamine deficit in patients with Parkinson's disease is the focus of both experimental and clinical investigations. Although there have been marked advances in the experimental and even clinical application of these xenogeneic transplantations, questions regarding the host's xenospecific immune response remain unanswered. It has been shown that human serum is able to lyse pfVM tissue by both anti-gal-gal and non-anti-gal-gal antibodies by complement activation. The aim of this study was to investigate whether interindividual differences exist in the levels of pfVM cell-specific IgM and IgG subclass antibodies, their ability to lyse pfVM cells in vitro and the relationship between both. Pig fetal VM cells were incubated with heat-inactivated serum from 10 different individuals and binding of IgM antibodies and IgG subclass antibodies to pfVM cells was analyzed by flow cytometry. The ability to lyse pfVM cells was analyzed exposing 51Cr-labeled pfVM cells to fresh serum or isolated IgM and IgG from the same individuals and subsequent determination of released 51Cr from lysed cells. Strong differences were found between individuals in the levels of pfVM cell-specific IgM antibodies: antibody levels differed up to 40-fold. pfVM-specific IgG1 and IgG2 levels were only detectable in a few individuals. The ability to lyse pfVM cells ranged from negligible lysis up to 66.5% specific lysis. There was a strong correlation between the levels of individual pfVM-specific IgM antibodies and the ability to lyse pfVM cells in vitro. Isolated IgM, but not IgG, was able to lyse pfVM cells in the presence of complement. In conclusion, the interindividual differences in the levels of IgM with affinity for pfVM cells and their ability to lyse pfVM cells in vitro are considerable. Only few individuals possessed IgG1 and IgG2 subclass antibodies with affinity for pfVM. These findings may influence patient selection for porcine transplants and chances of graft survival in individual patients.

Porcine Fetal Ventral Mesencephalic Cells are Targets for Primed Xenoreactive Human T Cells

Xenotransplantation of porcine fetal ventral mesencephalic (pfVM) cells to overcome the dopamine shortage in the striatum of patients with Parkinson's disease seems a viable alternative to allotransplantion of human fetal donor tissue, especially because the latter is complicated by both practical and ethical issues. There is, however, little known about the xenospecific immune responses involved in such an intracerebral xenotransplantation. The aim of our study was to investigate whether 1) naive human peripheral blood mononuclear cells (PMBC) display cytotoxicity against pfVM cells of E28 pig fetuses, and 2) priming of human PBMC by xenogeneic antigen presenting cells (APC) modulates pfVM-directed cellular cytotoxicity. For this purpose fresh PMBC from nine individual donors were primed by incubation with either irradiated pfVM cells or porcine spleen cells (PSC) as APC in the presence of IL-2 for 1 week before assessing cytotoxicity in a 51Cr release assay. Also, direct NK reactivity and antibody-dependent cellular cytotoxicity (ADCC) of fresh PMBC against pfVM cells was assessed. No direct cytotoxicity of naive cells (either NK reactivity or ADCC) against pfVM cells could be determined. Only PMBC primed with PSC were capable of lysing pfVM cells. PBMC primed with pfVM cells did not show cytolytic capacity towards pfVM. Interestingly, large differences in xenospecific T-cell responses exist between individual donor PBMC. Thus, human T cells are capable of killing pfVM cells in a xenoreactive response, but only after priming by donor APC. The large interindividual differences between human donors in their xenoreactive response may influence patient selection for xenotransplantation and chances of graft survival for individual patients.

A systematic review of the methodological quality and extent to which evaluation studies measure the usability of orthopaedic shoes

Objective: To determine the methodological quality of studies evaluating orthopaedic shoes and orthopaedic shoe provisions. To what extent do studies evaluating orthopaedic shoes prescribed for patients with degenerative disorders of the foot, rheumatoid arthritis, diabetes mellitus and neurological foot disorders, focus on the aspects of the International Organization for Standardization (ISO) definition of usability, i.e., effectiveness, efficiency, satisfaction, and context of use?

Design: Systematic review.

Methods: A systematic literature search was performed to identify randomized controlled trials (RCTs) concerning orthopaedic shoes and orthopaedic shoe inserts. The methodological quality of the studies was assessed independently by two raters, based on the 19 items of the ‘Maastricht–Amsterdam criteria list’. The studies were assessed against the parameters of the ISO definition of usability.

Results: Eleven RCTs were included. The methodological scores ranged from 8 to 14 out of 19 possible points. Eleven studies focused on the effectiveness of the orthopaedic shoes and orthopaedic shoe inserts, two of which reported outcome measures and conclusions related to the efficiency of the studied orthopaedic shoes and orthopaedic shoe inserts. Four studies reported some form of patient satisfaction and only three studies paid attention to the context of use.

Conclusions: The methodological quality of the RCTs as assessed according to the 19 different criteria varied considerably. The present review shows that current scientific literature concerning the usability of orthopaedic shoes focuses mainly on effectiveness at the expense of the other domains of usability, i.e., efficiency, satisfaction and context of use.

Physiological and behavioral reactions elicited by simulated and real-life visual and acoustic helicopter stimuli in dairy goats

Background

Anecdotal reports and a few scientific publications suggest that flyovers of helicopters at low altitude may elicit fear- or anxiety-related behavioral reactions in grazing feral and farm animals. We investigated the behavioral and physiological stress reactions of five individually housed dairy goats to different acoustic and visual stimuli from helicopters and to combinations of these stimuli under controlled environmental (indoor) conditions. The visual stimuli were helicopter animations projected on a large screen in front of the enclosures of the goats. Acoustic and visual stimuli of a tractor were also presented. On the final day of the study the goats were exposed to two flyovers (altitude 50 m and 75 m) of a Chinook helicopter while grazing in a pasture. Salivary cortisol, behavior, and heart rate of the goats were registered before, during and after stimulus presentations.

Results

The goats reacted alert to the visual and/or acoustic stimuli that were presented in their room. They raised their heads and turned their ears forward in the direction of the stimuli. There was no statistically reliable rise of the average velocity of moving of the goats in their enclosure and no increase of the duration of moving during presentation of the stimuli. Also there was no increase in heart rate or salivary cortisol concentration during the indoor test sessions. Surprisingly, no physiological and behavioral stress responses were observed during the flyover of a Chinook at 50 m, which produced a peak noise of 110 dB.

Conclusions

We conclude that the behavior and physiology of goats are unaffected by brief episodes of intense, adverse visual and acoustic stimulation such as the sight and noise of overflying helicopters. The absence of a physiological stress response and of elevated emotional reactivity of goats subjected to helicopter stimuli is discussed in relation to the design and testing schedule of this study.

Effects of age and content of augmented feedback on learning an isometric force-production task

This study addressed the interaction between age and the informational content of feedback on learning an isometric force-production task. Healthy men and women (30 young adults: 20 to 35 years; 30 older adults: 55 to 70 years) were randomly assigned to a certain type of feedback: knowledge of results or kinetic feedback. Results showed no differences between young and older adults in the accuracy and consistency of performance. There were no interactions of age with any of the feedback-related variables. These findings suggest that the effects of augmented feedback on motor learning are similar in both young and older adults.

Virtual reality for mobility devices: training applications and clinical results: a review

Virtual reality technology is an emerging technology that possibly can address the problems encountered in training (elderly) people to handle a mobility device. The objective of this review was to study different virtual reality training applications as well as their clinical implication for patients with mobility problems. Computerized literature searches were performed using the MEDLINE, Cochrane, CIRRIE and REHABDATA databases. This resulted in eight peer reviewed journal articles. The included studies could be divided into three categories, on the basis of their study objective. Five studies were related to training driving skills, two to physical exercise training and one to leisure activity. This review suggests that virtual reality is a potentially useful means to improve the use of a mobility device, in training one's driving skills, for keeping up the physical condition and also in a way of leisure time activity. Although this field of research appears to be in its early stages, the included studies pointed out a promising transfer of training in a virtual environment to the real-life use of mobility devices.

Effectiveness of custom-made orthopaedic shoes in the reduction of foot pain and pressure in patients with degenerative disorders of the foot

BACKGROUND

Degenerative disorders of the foot often are painful during standing and walking. It is assumed that, because of bone deformity, callus, and deformity of the plantar pads, the plantar pressure distribution changes. Prescription of orthopaedic shoes for patients with degenerative disorders of the foot is based on the hypothesis that excessive pressure under the foot causes pain. The goal of this study was to evaluate the effectiveness of custom-made orthopaedic shoes, in terms of pressure and pain, in patients with degenerative disorders of the foot. Additionally, the relationship between plantar pressure parameters and foot pain was studied, with special emphasis on second and third metatarsal heads.

METHODS

Seventy-seven consecutive patients with degenerative disorders of the foot were recruited from the outpatient clinics of seven rehabilitation centers and rehabilitation departments of university hospitals in the Netherlands. The study was prospective. The Questionnaire for Usability Evaluation for Orthopaedic Shoes was used to measure perceived foot pain. To measure plantar pressures, the Pedar in-shoe pressure measurement system (Novel GmbH, Munich) was used. The effectiveness of custom-made orthopaedic shoes, in terms of pressure and pain in patients with degenerative disorders of the foot, was analyzed by means of a paired sample t-test. To select the pressure parameter (Pmax, P(TI,) and P(av)) most closely associated with walking pain, within-subject correlation coefficients were calculated.

RESULTS

Custom-made orthopaedic shoes significantly decreased perceived foot pain by at least 23%, and significantly reduced plantar pressure under all foot regions by at least 9%. A significant correlation (r = 0.521) was found between walking pain and the average pressure beneath the second and third metatarsal heads.

CONCLUSIONS

Based on these results, it can be concluded that custom-made orthopaedic shoes are effective in reducing foot pain and foot pressure. The moderate (significant) relationship between average pressure and walking pain can be used as a tool for evaluating custom-made orthopaedic shoes prescribed for patients with degenerative disorders of the foot.

Artificial feedback for remotely supervised training of motor skills

Electromyographic (EMG) biofeedback can be used to train motor functions at a distance, which makes therapy at home a possibility. To enable patients to train properly without the presence of a therapist, artificial feedback is considered essential. We studied the combined effect of age and timing of artificial feedback on training muscle relaxation in 32 healthy subjects (younger: 20-35 years; older: 55-70 years). All subjects improved their performance significantly (F = 6.1, P<0.001). The effect of different timing of feedback (feedback provided during or after performance) was similar in young and older adults. However, this conclusion should be interpreted with caution owing to the small sample size. It can be argued that the artificial feedback used was too complicated for older adults to interpret. When designing remotely supervised treatment programmes, one should consider carefully the way that artificial feedback is being applied as it may enable (elderly) subjects to train without the presence of a therapist.

Effects of Age and Timing of Augmented Feedback on Learning Muscle Relaxation While Performing a Gross Motor Task

OBJECTIVE

To examine the combined effect of age and timing of augmented feedback on learning muscle relaxation. Performing a gross motor task, subjects had to lower their trapezius muscle activity using the electromyographic signal as visual myofeedback.

DESIGN

Healthy subjects (16 young adults: 20-35 yrs; and 16 older adults: 55-70 yrs) were randomly assigned to one of two timing conditions of myofeedback: concurrent (feedback was provided immediately during the trial) and terminal (feedback was provided delayed after the trial) condition.

RESULTS

The results indicated that young adults had a higher level of motor performance (i.e., lower muscle activity) compared with older adults when myofeedback was provided. These effects persisted during short- (after 10 mins) and long-term retention (after 1 wk) when no myofeedback was provided. In contrast to young adults, older adults did not improve their performance throughout the experiment. There were no interactions of age with the timing conditions of myofeedback during acquisition and retention.

CONCLUSIONS

Either timing condition of augmented feedback was equally helpful to young adults, whereas neither was helpful for older adults in learning muscle relaxation.

Effect of augmented feedback on motor function of the affected upper extremity in rehabilitation patients: a systematic review of randomized controlled trials

OBJECTIVE

Assessment of the available evidence regarding the effect of augmented feedback on motor function of the upper extremity in rehabilitation patients.

METHODS

A systematic literature search was performed to identify randomized controlled trials that evaluated the effect of augmented feedback on motor function. Two reviewers systematically assessed the methodological quality of the trials. The reported effects were examined to evaluate the effect of therapeutic interventions using augmented feedback and to identify a possible relationship with patient characteristics, type of intervention, or methodological quality.

RESULTS

Twenty-six randomized controlled trials were included, 9 of which reported a positive effect on arm function tests. Follow-up measurements were performed in 8 trials, 1 of which reported a positive effect. Different therapeutic interventions using augmented feedback, i.e. electromyographic biofeedback, kinetic feedback, kinematic feedback, or knowledge of results, show no difference in effectiveness.

CONCLUSION

No firm evidence was found of effectiveness regarding the use of augmented feedback to improve motor function of the upper extremity in rehabilitation patients. Future studies should focus more on the content, form and timing of augmented feedback concerning the therapeutic intervention. It should be emphasized that motor learning effects can only be determined by re-examining the population after a follow-up period.