Survey of Toxoplasma gondii Exposure in Muskrats in a Relatively Pristine Ecosystem.

Waterborne transmission of Toxoplasma gondii is assumed to be enhanced in areas with human-altered landscapes (e.g., urbanization, agriculture) and increased populations of non-native domestic and feral cats (Felis catus). However, little is known concerning T. gondii exposure risks in more natural watersheds (e.g., reduced human footprint, no domestic or feral cats) to establish a baseline for comparisons. In this study, muskrats (Ondatra zibethicus) were used as sentinels to assess baseline T. gondii exposure in a relatively pristine watershed in the Greater Voyageurs Ecosystem, northern Minnesota, during the summers of 2018-2019. Toxoplasma gondii antibodies were assayed in sera of live-trapped muskrats (n = 70) using a modified agglutination test. None of our samples were positive for T. gondii antibodies (P = 0.00, 95% Wald Score Confidence Interval = 0.00-0.05). This study establishes a baseline to compare T. gondii waterborne transmission risks in other human-modified watersheds.

Electrically Tunable Flat Bands and Magnetism in Twisted Bilayer Graphene.

Twisted graphene bilayers provide a versatile platform to engineer metamaterials with novel emergent properties by exploiting the resulting geometric moiré superlattice. Such superlattices are known to host bulk valley currents at tiny angles (α≈0.3°) and flat bands at magic angles (α≈1°). We show that tuning the twist angle to α^{*}≈0.8° generates flat bands away from charge neutrality with a triangular superlattice periodicity. When doped with ±6 electrons per moiré cell, these bands are half-filled and electronic interactions produce a symmetry-broken ground state (Stoner instability) with spin-polarized regions that order ferromagnetically. Application of an interlayer electric field breaks inversion symmetry and introduces valley-dependent dispersion that quenches the magnetic order. With these results, we propose a solid-state platform that realizes electrically tunable strong correlations.

Summarizing US Wildlife Trade with an Eye Toward Assessing the Risk of Infectious Disease Introduction.

The aim of this study was to characterize the role of the USA in the global exchange of wildlife and describe high volume trade with an eye toward prioritizing health risk assessment questions for further analysis. Here we summarize nearly 14 years (2000-2013) of the most comprehensive data available (USFWS LEMIS system), involving 11 billion individual specimens and an additional 977 million kilograms of wildlife. The majority of shipments contained mammals (27%), while the majority of specimens imported were shells (57%) and tropical fish (25%). Most imports were facilitated by the aquatic and pet industry, resulting in one-third of all shipments containing live animals. The importer reported origin of wildlife was 77.7% wild-caught and 17.7% captive-reared. Indonesia was the leading exporter of legal shipments, while Mexico was the leading source reported for illegal shipments. At the specimen level, China was the leading exporter of legal and illegal wildlife imports. The number of annual declared shipments doubled during the period examined, illustrating continually increasing demand, which reinforces the need to scale up capacity for border inspections, risk management protocols and disease surveillance. Most regulatory oversight of wildlife trade is aimed at conservation, rather than prevention of disease introduction.

Trends in the number and administrative characteristics of medical school health promotion programmes.

Over the course of almost 10 years, 1988-97, there has been a significant decline in the number of United States and Canadian medical schools offering health promotion programmes for students. All efforts should be made to enhance the overall health and well-being of medical students and to increase the number of health promotion programmes for them.

Contribution of aerosols generated during mixing and loading of pesticides to operator inhalation exposure.

The occupational exposure resulting from the application of crop protection agents continues to be of great interest for the purposes of identifying hazards or determining safer chemical handling methods. The purpose of the present study was to identify the potential respirator exposure of a mixer/loader to chlorothalonil, with the mixing and loading operation as the only source of aerosols (particles <13 microm diameter). Three worst-case mixing/loading scenarios were simulated in the lab: (1) a spill of undiluted chlorothalonil formulation onto a dry, horizontal metal surface; (2) a spill of undiluted chlorothalonil formulation onto a rapidly rotating shaft; and (3) pouring undiluted chlorothalonil formulation into a container of water. Aerosol generation from these scenarios was compared to that resulting from atomizing dilute chlorothalonil through hydraulic nozzles. Aerosols were captured with a cascade impactor, and quantified by gas chromatography. Results indicated that simulated spill scenarios generated aerosol concentrations between 2.1 and 5.3 ng/l, which were in the same order of magnitude as, and only marginally higher than, the detection threshold (1.7 ng/l) and background levels (2.2 ng/l). In comparison, atomization of dilute chlorothalonil through a hollow cone and flat fan nozzles resulted in airborne concentrations of 354 and 96 ng/l, respectively, related to the atomization characteristics of these nozzles. Measurement of the dimensions of the aerosol cloud indicated that aerosols resulting from a spill amounted to approximately 10(-5)% of the spilled chlorothalonil. It was estimated that a male worker respiring 29 l/min would inhale approximately 0.32-0.78 ng of chlorothalonil during a typical 30 s spill, assuming a 1% transfer efficiency between the spill site and the mixer/loader. These estimates were between 10000 and 480000 times less than literature data for respiratory exposure of chlorothalonil by applicators and harvesters, suggesting that inhalation of aerosols from mixing and loading represents a minor component of overall exposure.

Flexor carpi ulnaris tendon transfers in cerebral palsy.

Flexor carpi ulnaris tendon transfer to either the extensor carpi radialis longus or extensor carpi radialis brevis has become a standard procedure to improve function in patients with cerebral palsy. In this retrospective study of the procedure, we have compared preoperative and postoperative wrist position, analysed potential outcome predictors and assessed function by objective and subjective measures. Sixteen children, with flexor carpi ulnaris transfer to extensor carpi radialis longus or brevis or extensor digitorum, were tested at an average follow-up of 4 years (range, 1-9). General resting position improved and the centre of the arc of motion averaged 6 degrees pronation and 9 degrees extension. Subjectively, 14 of 16 parents felt there was an improvement in function, 16 of 16 felt that cosmesis was improved, 14 of 16 would recommend the procedure to others, and 15 of 16 were satisfied overall.

A Four-year Study of Anxiety, Depression, Loneliness, Social Support, and Perceived Mistreatment in Medical Students.

The goal of this study was to examine anxiety, depression, loneliness, social support, and perceived mistreatment at 4 time points over the course of the 4 years of undergraduate medical education, beginning in 1991. Representative samples of medical students completed a battery of questionnaires at freshman orientation (111 of 189 students = 59 percent), end of the first year (114 of 182 students = 63 percent), end of the second year (96 of 189 students = 51 percent), and end of the fourth year (85 of 192 students = 44 percent). Depression and anxiety were highest at the end of the first year and lowest at the end of the fourth year. Perceived mistreatment, particularly of a psychological nature, was pervasive over the course of 4 years of medical education. Perceived mistreatment was significantly positively correlated with depression and anxiety at freshman orientation and at the end of the first year. The implications of these findings are discussed with a view to making reforms in medical education designed to enhance the professional and personal development of each student.

A survey of health promotion programs in U.S. and Canadian medical schools.

The results of the survey indicate that 55 of 142 schools currently offer a health promotion/well-being program for their students. A total of 11 programs have been added since a similar survey was conducted in 1988. A diversity of program components that could be individualized to the needs of each student were offered, as can be seen in Table 1. Eight different components were offered in more than 50% of the schools, with support groups and substance abuse services being offered in 74.5% of the schools. It is noteworthy that health promotion/well-being programs are only offered at about 20% of medical schools for interns/residents and faculty/staff, although it is possible that they might participate in other programs. It should be pointed out that in more than 95% of the schools, physical/medical and psychologic services were offered; however, specific programs designed to prevent substance and alcohol abuse were only offered in about 54% of the programs.

The process of coping with a gross anatomy exam during the first year of medical school.

A total of 42 freshman medical students were evaluated before a major exam, after the exam and before grades were announced and after grades were announced. They completed measures relating to mood, emotions, coping, social support and stakes. Significant time and academic performance differences were found in many domains.

Age and sex modulate effects of stress on the immune system: a multivariate analysis.

Multivariate analyses indicate that both age and sex can modulate examination stress effects on immune factors. Stress lowered eosinophil counts in females but raised them in males. Age modulated stress effects on CD4 and CD8 cells, hemoglobin, and erythrocytes. CD4 decreased more in older subjects; CD8 increased in older and decreased in younger subjects; hemoglobin decreased in younger but not older subjects; erythrocytes increased in older and decreased in younger subjects. Initial age and/or sex differences in levels of neutrophils and lymphocytes were not statistically altered by stress. Stress effects not modulated by age or sex increased serum IgA and IgM, CD19, and stimulated phagocytic activity but decreased serum IgG, CD3, basophils, and unstimulated phagocytic activity. The immunological effects of stress are multiple and are influenced by variations in age and sex of the person.

Stress, coping and health: enhancing well-being during medical school.

Medical education can be a health hazard for many students, and far-reaching reforms are needed to improve it. This article reviews the literature on stress, coping and health during undergraduate medical education. The conclusions drawn from this review are used as a basis for advancing recommendations to improve medical education. It is essential to incorporate the principles of health promotion and disease prevention throughout medical education in order to minimize and prevent later burn-out and impairment. Healthy medical students are likely to become healthy doctors who can then model and promote healthy lifestyles with their patients. This preventive approach to health care can lead to an improvement in our health care delivery system.

Perceived mistreatment of graduating dental students: a retrospective study.

This study assessed types and sources of perceived mistreatment among graduating dental students. A total of 38 of 46 (83 percent) students anonymously completed a mistreatment questionnaire. All 38 students perceived experiencing at least one type of mistreatment from some source and reported an average of about 35 separate incidents. Psychological mistreatment was most frequent with physical mistreatment reported relatively infrequently. Classmates and clinical faculty were the most frequent sources of mistreatment. Sexual harassment was perceived by about one-third of the students. The potentially adverse effects of perceived mistreatment were discussed with a view to improving dental education through an emphasis on stress management, environmental change, and self-responsibility for health designed to enhance the personal growth of each dental student.

Psychosocial changes during the first year of medical school.

The goal of this study was to assess psychosocial changes during the first year, on measures thought related to the long-term adjustment of medical students. Measures of self-esteem, health locus of control, hassles, uplifts, mood, and symptoms of stress were administered at the beginning and end of first year to 128 of 181 students. Self-esteem, powerful other locus of control, and uplifts decreased while hassles increased during the year. Positive mood decreased (joy, contentment, vigour, and affection) while negative mood increased (depression and hostility). Hassles at the beginning of the year were positively associated with health outcome at the beginning and end of the year. End-of-the-year first-year students appear to be worse off psychosocially than when they entered. With greater emphasis on health promotion and disease prevention and the adoption of other reforms in medical education, as suggested in the GPEP Report, medical students may learn to cope more effectively with stress as they pursue their medical education.

Perceived mistreatment and attitude change by graduating medical students: a retrospective study.

The goal of this study was to assess types and sources of perceived mistreatment, perceived attitude change, and academic performance of graduating medical students. A total of 87 of 143 (61%) students anonymously completed a mistreatment questionnaire, an attitude questionnaire, and questions about academic performance. The percentage of mistreatment was widespread (98.9%) with psychological mistreatment (shouting and humiliating) by residents/interns being most frequent. Over half of the students perceived sexual harassment, with women reporting greater harassment than men. There was a high incidence of disparaging remarks about doctors and medicine as a profession from a variety of sources. Increased mistreatment was positively associated with a perceived increase in cynicism. The potentially adverse effects of mistreatment on the individual student, the teacher-student relationship, and the doctor-patient relationship are discussed with recommendations for improving medical education.

Relationship of coping style to affective state and perceived social support in asymptomatic and symptomatic HIV-infected persons: implications for clinical management.

The authors describe the relationship of three coping styles to affective state (mood) and perceived social support in 29 human immunodeficiency virus (HIV)-infected homosexual/bisexual men between the ages of 18 and 45 years. Active-behavioral coping was significantly related to enhanced mood and greater perceived social support. Avoidance coping was significantly related to greater mood disturbance and lower social support. No relationships were found for active-cognitive coping. Recommendations for clinical management of HIV-infected persons and their traditional and/or nontraditional family follow from the findings.

A biopsychosocial examination of symptomatic and asymptomatic HIV-infected patients.

This study evaluated twenty-nine symptomatic and asymptomatic HIV-infected homosexual/bisexual men between eighteen and forty-five in the areas of psychiatric/psychosocial, neuropsychological, family, and immunological functioning. The subjects were referred by physicians, nurses, and mental health professionals from the Tulane/Louisiana State University AIDS Clinical Trials Unit and the C-100 outpatient Primary Care Clinic for HIV-infected patients served within the Charity Hospital of Louisiana at New Orleans. All subjects and their significant others were evaluated between November 1987 and October 1988 at the C-100 Clinic. The outcome measures were mood disturbance, psychological distress, and CD4 cell count. The most significant other family member, as selected by each subject, completed family measures. The subjects experienced psychological distress and neuropsychological problems. Active-behavioral coping appeared adaptive (related to enhanced mood) as did perceived social support (related to positive mood and lower psychological distress). Higher levels of neuropsychological functioning (verbal memory, visual memory, motor speed, and visual-motor sequencing) were associated with enhanced psychosocial functioning and/or immunological status. The findings from this study highlight the importance of conducting longitudinal studies using a multidimensional approach in which HIV-infected persons and their most significant other family members are evaluated within a biopsychosocial model.

A retrospective study of attitude change during medical education.

A retrospective attitude questionnaire was administered to 70 of 157 graduating seniors at the end of the medical school year. Students perceived that they became more cynical during medical education. In addition, they perceived that they were more concerned with making money, more concerned for patients, and more helpful. These findings relate to the developmental stressors of medical education as they affect the individual student. Burn-out and impairment are possible consequences; a preventive approach is advocated.