A comparison of forearm bone mineral density among collegiate gymnasts, distance runners, and non-athletes [abstract]

Purpose: Low regional bone mineral density (BMD) has been correlated with increased fracture incidence in several body regions. Higher forearm BMD has been observed in athletes of several impact loading sports and decreases the risk of Colles' fracture. The purpose of this study was to compare BMD in female collegiate gymnasts to a group of athletic controls (collegiate distance runners) and a group of non-athletic controls (non-athletes). Methods: Female collegiate artistic gymnasts (n=11), collegiate distance runners (n=9), and college-age non-athletes (n=25) underwent whole-body and dominant forearm DXA scans to assess whole-body BMD and body composition and sitespecific BMD of the dominant forearm. Weight and height were measured and used to determine BMI. Data for athletes were collected after the midpoint of their competitive seasons. Results: Differences were found between gymnasts and non-athletes and between gymnasts and runners at the total radius, 1/3 distal radius, and ultradistal radius (p<0.000), with gymnasts exhibiting significantly higher BMD at the three forearm sites than either distance runners or non-athletes. Differences between runners and non-athletes were not significant. Conclusions: The loading impact and site-specificity of gymnastics exercise on the forearm likely caused the increase in bone mineral density at both cortical and trabecular bone sites

The Effects of Laboratory Stress on Appraisal of Control in Bulimia

Recent work pertaining to bulimia has shown that bulimics tend to perceive themselves as having a decreased ability to control their environments, particularly when faced with a stressful situation. Results from studies examining the type or amount of stress experienced by bulimics have been inconsistent. The transactional model of stress, which calls for the examination of an individual\u27s appraisal of a situation, provides a more advanced method of measuring stress than has generally been used in past studies. The present study sought to examine bulimics\u27 perceptions of control in stressful and nonstressful situations using an in vivo behavioral task, Thirty female undergraduate bulimics and thirty noneating-oisordered controls engaged in a 40 trial contingency-learning task in which they estimated the amount of control they could exert. Half of the subjects were placed in a stressful condition, which involved a statement linking their performance with their intellectual functioning. The results of the study failed to demonstrate that bulimics perceived themselves as having less control than the noneating-disordered control subjects. However, this study was unable to address whether the stress could elicit differences in the appraisal of control as the stress manipulations proved unsuccessful. This study did find, however, that for bulimic subjects, increases in amount of behavioral involvement (i.e., button-pressing) did not result in increases in perceived control, as was the case for the noneating-disordered control subjects. These results are interpreted within a learned helplessness framework as suggesting that bulimics may not view themselves as being able to exert control over their lives, regardless of the amount of effort they exert

Mobilization of Trace Elements in Aquifers by Biodegradation of Hydrocarbon Contaminants

This study had two objectives: (1) to determine the extent of metal mobility within petroleum-contaminated aquifers, (2) to determine if biodegradation of petroleum hydrocarbons can explain metal mobility. The approach reviewed analytical results from 2305 groundwater sampling events, taken from 958 wells, located at 136 sites found at 53 Air Force installations. The study showed that high levels of metals are present at petroleum hydrocarbon sites where metals would not generally be expected. Of the metals with drinking water maximum contaminant levels (MCLs), mercury and silver were detected the least frequently. Barium and copper were detected at the sites, but fewer than 2.5 percent of the samples exceeded their MCLs. All other metals exceeded their MCLs in at least 2.5 percent of the samples, with antimony and lead exceeding their MCLs in 19 percent and 10 percent of samples, respectively. Higher concentrations of barium and manganese were most strongly correlated with petroleum hydrocarbon contamination, and relatively strong correlations also existed for aluminum, arsenic, iron, and lead. Major cations such as calcium, magnesium, sodium and potassium were least affected by petroleum hydrocarbons concentrations

Short-term aerobic exercise training in type 2 diabetes

Type 2 diabetes (T2D) is a worldwide problem, and people with T2D have impaired postprandial glycemia (PPG). While current pharmaceutical therapies are targeted to reduce glycosylated hemoglobin and may not be effective in improving PPG, exercise is an effective treatment to enhance postprandial glycemic control in patients with T2D. As little as seven days of aerobic exercise has been shown to reduce PPG, but the mechanisms by which this occurs are not understood. Further, the assessment of PPG generally is done using a non-physiological glucose overload uncharacteristic of normal human feeding. Thus, the primary aims of this dissertation were: 1) to identify tissues contributing to changes in glycemic control after short-term exercise training and identify the systemic mechanisms by which exercise improves overall PPG in patients with T2D, and 2) to determine if a mixed meal tolerance test is a more valid tool for assessing improvements in glycemic control following exercise training than the standard oral glucose tolerance test in T2D. Our findings support that improved insulin sensitivity is an early adaptation of exercise training, but we did not see improvements in overall PPG in the sample studied. We also found that a mixed meal test is an effective alternative to the oral glucose tolerance test in assessing differences in PPG. Collectively, when viewed in the presence of the existing literature, these data suggest that while exercise training is ultimately known to enhance postprandial glycemic control, and testing this with a mixed meal test is a viable alternative to the current oral glucose tolerance test, subjects with T2D have variable responses and may not always see improvements in PPG following one week of aerobic exercise training

Temporal-Difference Learning to Assist Human Decision Making during the Control of an Artificial Limb

In this work we explore the use of reinforcement learning (RL) to help with human decision making, combining state-of-the-art RL algorithms with an application to prosthetics. Managing human-machine interaction is a problem of considerable scope, and the simplification of human-robot interfaces is especially important in the domains of biomedical technology and rehabilitation medicine. For example, amputees who control artificial limbs are often required to quickly switch between a number of control actions or modes of operation in order to operate their devices. We suggest that by learning to anticipate (predict) a user's behaviour, artificial limbs could take on an active role in a human's control decisions so as to reduce the burden on their users. Recently, we showed that RL in the form of general value functions (GVFs) could be used to accurately detect a user's control intent prior to their explicit control choices. In the present work, we explore the use of temporal-difference learning and GVFs to predict when users will switch their control influence between the different motor functions of a robot arm. Experiments were performed using a multi-function robot arm that was controlled by muscle signals from a user's body (similar to conventional artificial limb control). Our approach was able to acquire and maintain forecasts about a user's switching decisions in real time. It also provides an intuitive and reward-free way for users to correct or reinforce the decisions made by the machine learning system. We expect that when a system is certain enough about its predictions, it can begin to take over switching decisions from the user to streamline control and potentially decrease the time and effort needed to complete tasks. This preliminary study therefore suggests a way to naturally integrate human- and machine-based decision making systems.Comment: 5 pages, 4 figures, This version to appear at The 1st Multidisciplinary Conference on Reinforcement Learning and Decision Making, Princeton, NJ, USA, Oct. 25-27, 201

Effect of carrageenan on the non-specific resistance of mice to injected syngeneic tumour cells, alone or in mixtures.

The mechanisms of non-specific resistance to syngeneic methylcholanthrene-induced fibrosarcomas of mice were investigated. Results showed that a small tumour graft of 0.05 X 10(5) cells is greatly enhanced in growth when admixed with large numbers of cell fragments, killed cells or viable non-replicating cells. The enhancement of small tumour grafts in cell mixtures was found to be non-specific. Carrageenan, a known anti-macrophage agent, significantly increased tumour growth in normal mice. However, it did not enhance the increased tumour growth of 0.05 X 10(5) cells mixed with 10(6) viable, non-replicating mitomycin C-treated tumour cells. The latter observation indicates that carrageenan and admixed cells interfere with the same tumour-inhibitory mechanism and therefore cannot produce additive effects. The results give support to the concept of a non-specific macrophage "surveillance" system which appears crucial in controlling tumour growth, since it determines the establishment of small numbers of tumour cells while they can still be easily destroyed

Potential health impacts of heavy metals on HIV-infected population in USA.

Noninfectious comorbidities such as cardiovascular diseases have become increasingly prevalent and occur earlier in life in persons with HIV infection. Despite the emerging body of literature linking environmental exposures to chronic disease outcomes in the general population, the impacts of environmental exposures have received little attention in HIV-infected population. The aim of this study is to investigate whether individuals living with HIV have elevated prevalence of heavy metals compared to non-HIV infected individuals in United States. We used the National Health and Nutrition Examination Survey (NHANES) 2003-2010 to compare exposures to heavy metals including cadmium, lead, and total mercury in HIV infected and non-HIV infected subjects. In this cross-sectional study, we found that HIV-infected individuals had higher concentrations of all heavy metals than the non-HIV infected group. In a multivariate linear regression model, HIV status was significantly associated with increased blood cadmium (p=0.03) after adjusting for age, sex, race, education, poverty income ratio, and smoking. However, HIV status was not statistically associated with lead or mercury levels after adjusting for the same covariates. Our findings suggest that HIV-infected patients might be significantly more exposed to cadmium compared to non-HIV infected individuals which could contribute to higher prevalence of chronic diseases among HIV-infected subjects. Further research is warranted to identify sources of exposure and to understand more about specific health outcomes

Liquid meal composition, postprandial satiety hormones, and perceived appetite and satiety in obese women during acute caloric restriction

OBJECTIVE: The purpose of this study was to compare postprandial satiety regulating hormone responses (pancreatic polypeptide (PP) and peptide tyrosine tyrosine (PYY)) and visual analog scale- (VAS) assessed perceived appetite and satiety between liquid high-protein (HP) and high-carbohydrate (HC) meals in obese women during acute (24-h) caloric restriction. DESIGN: Eleven obese premenopausal women completed two conditions in random order in which they consumed 1500 calories as six 250-calorie HP meals or six 250-calorie HC meals over a 12-h period. Blood samples were taken at baseline and every 20 min thereafter and analyzed for PP and PYY concentrations. At these same points, perceived hunger and fullness were assessed with a VAS. The incremental area under the curve (iAUC) was used to compare postprandial responses. RESULTS: THE 12-H PP AND PYY IAUC WERE GREATER (P0.05) DURING THE HP CONDITION (PP: 4727±1306 pg/ml×12 h, PYY: 1373±357 pg/ml×12 h) compared with the HC condition (PP: 2300±528 pg/ml×12 h, PYY: 754±246 pg/ml×12 h). Perceived hunger and fullness were not different between conditions (P>0.05). The greatest changes in PYY and perceived fullness occurred after the morning meals during both conditions. CONCLUSIONS: These data suggest that in obese women during acute caloric restriction before weight loss, i) liquid HP meals, compared with HC meals, result in greater postprandial PP and PYY concentrations, an effect not associated with differential appetite or satiety responses, and ii) meal-induced changes in PYY and satiety are greatest during the morning period, regardless of dietary macronutrient composition

Effects of carrageenan, PVP and tumour-bearer serum on immunity induced by excision or mitomycin C-treated tumour cells in mice

Carrageenan (Cg) was tested for its effects on the growth of, and immunity to, 2 methylcholanthrene-induced syngeneic murine fibrosarcomas (H1 and H2). The tumours were found not to share major tumour-specific transplantation antigens. H2 appeared more immunogenic than H1. In contrast to H1, immunity induced by H2 was not affected by Cg, nor was its growth in Cg-treated normal mice augmented

On-farm Cooperator Trials 2011: Effect of Extended-duration Row Covers on Muskmelon and Winter Squash on Bacterial Wilt and Yield

Susceptible cucurbit crops are difficult to grow in Iowa because of bacterial wilt, caused by Erwinia tracheiphila. Striped and spotted cucumber beetles transmit bacterial wilt. Other insect pests such as squash vine borer and squash bugs may also have an economic impact on yield, particularly in squash