Modular hip exoskeleton improves walking function and reduces sedentary time in community-dwelling older adults

Numerous studies showed that postural balance improves through light touch on a stable surface highlighting the importance of haptic information, seemingly downplaying the mechanical contributions of the support. The present study examined the mechanical effects of canes for assisting balance in healthy individuals challenged by standing on a beam. Sixteen participants supported themselves with two canes, one in each hand, and applied minimal, preferred, or maximum force onto the canes. They positioned the canes in the frontal plane or in a tripod configuration. Statistical analysis used a linear mixed model to evaluate the effects on the center of pressure and the center of mass. The canes significantly reduced the variability of the center of pressure and the center of mass to the same level as when standing on the ground. Increasing the exerted force beyond the preferred level yielded no further benefits, although in the preferred force condition, participants exploited the altered mechanics by resting their arms on the canes. The tripod configuration allowed for larger variability of the center of pressure in the task-irrelevant anterior–posterior dimension. High forces had a destabilizing effect on the canes: the displacement of the hand on the cane handle increased with the force. Given this static instability, these results show that using canes can provide not only mechanical benefits but also challenges. From a control perspective, effort can be reduced by resting the arms on the canes and by channeling noise in the task-irrelevant dimensions. However, larger forces exerted onto the canes can also have destabilizing effects and the instability of the canes needs to be counteracted, possibly by arm and shoulder stiffness. Insights into the variety of mechanical effects is important for the design of canes and the instructions of how to use them.     

Longitudinal relationships between visual acuity and severe depressive symptoms in older adults: the Salisbury Eye Evaluation study

Objectives: To assess the longitudinal relationship between visual acuity (VA) and depressive symptoms (DSs) among older adults.

Methods: A population-based sample of 2520 white and black individuals aged 65–84 years in 1993--1995 was assessed at baseline and at two, six, and eight years later. Presenting and best-corrected VA was assessed using early treatment diabetic retinopathy study chart. DSs were assessed using the severe depression subscale of General Health Questionnaire 28. Latent growth curve models estimated VA and DS trajectories and age-adjusted associations between trajectories.

Results: Best-corrected logMAR VA worsened over time (slope = 0.026, intercept = 0.013, both p < 0.001). No change in DS over time was observed (slope = ?0.001, p = 0.762; intercept = 1.180, p < 0.001). However, a small change in DS was observed in participants who completed all rounds (slope = 0.005, p = 0.015). Baseline VA levels correlated with baseline DS levels (r = 0.14, p < 0.001). Baseline DS was associated with best-corrected VA change (r = 0.17, p = 0.01). Baseline best-corrected VA was not associated with DS change (r = 0.017, p = 0.8). Best-corrected VA change was not significantly associated with DS change (r = ?0.03, p = 0.7).

Discussion: DSs are significantly associated with VA cross-sectionally, and persons with higher baseline DS scores were more likely to experience worsening VA over time. The complex relationship between visual impairment and DS suggests the need for a continued effort to detect and treat both visual decline and severe DSs in a growing elderly population.     

A study of steady state and kinetic regulation of chloride ion and osmotic pressure in hemolymph of oysters,Crassostrea virginica,exposed to tri-n-butyltin

Two sets of experiments were made to determine ifbis(tri-n-butyl)tin oxide (TBT) [IUPAC: hexabutyldistannoxane] influenced osmotic pressure or chloride ion concentration in hemolymph of adult American oysters,Crassostrea viginica. In the first set, oysters were acclimated to 5, 25, or 40%, then exposed to bis(tri-n-butyl)tin oxide dissolved in seawater (0.5, 1.0 or 2.0 g/L) for 11 days. Measurements of the total osmotic pressure and chloride ion concentration in hemolymph indicated that mean values of neither was significantly affected under steady state conditions. Oysters exposed to TBT exhibited a higher variation around the mean value for both total osmotic pressure and chloride ion concentration. There was significant mortality of oysters exposed to TBT in 25 and 40, but not in 5%. In a second experiment, adult oysters were acclimated to 25% and simultaneously exposed to the TBT concentrations listed above for 10 days. Then, subgroups of oysters were abruptly moved to 5 or 40% and the time-course of adjustment of hemolymph osmotic pressure and chloride ion concentration was measured. During the first 24 hr, there was little adjustment to 5% in controls or TBT exposed oysters; apparently, they remained closed most or all of the time. In marked contrast, hemolymph of oysters moved to higher salinities rapidly readjusted. Exposure to TBT had a delaying effect on the schedule of the increase in hemolymph osmotic pressure and chloride ion concentration. Results of these experiments show that TBT has an indirect effect on osmotic pressure and chloride ion concentration adjustment in oysters; it does not appear to act strongly as an anionophore to influence anion transfer across epithelia.     

Complex evaluation of the work of physician-endoscopy specialists

The presented system of quantitative criteria for assessing hospital physicians' work is based on the results of comparative evaluation of actual labour activity along with the standard and mean indicators. Physician's work is assessed by three main factors: amount of work (intensity); complicacy; quality with further introduction of an integral indicator. Complex approach, relative simplicity of labour accounting, derivation of estimates and availability of objective (standard) limits enable one to use this system as the basis for improving labour management of both separate medical workers and health establishments as a whole.