Reference apparatus for medical ultrasonic transducer

Once reference apparatus has been located properly, and its position on chest of patient has been recorded on skin by means of indelible fiducial marks, it is simple matter at later time to reposition probe on chest over heart. In this way, signals from exact same area of heart can be re-examined

A pilot study of medical student attitudes to, and use of, commercial movies that address public health issues

<p>Abstract</p> <p>Background</p> <p>An innovative approach to learning public health by using feature-length commercial movies was piloted in the fourth year of a medical degree. We aimed to explore how students responded to this approach and the relative effectiveness of two promotional strategies. Firstly we placed DVDs of 15 movies (with public health-related content) in the medical school library. Then alternating groups of students (total n = 82 students) were exposed to either a brief promotional intervention or a more intensive intervention involving a class presentation. The response rates were 99% at baseline and 85% at follow-up.</p> <p>Findings</p> <p>The level and strength of support for using movies in public health training increased after exposure to the public health module with significantly more students "strongly agreeing". Student behaviour, in terms of movies viewed or accessed from the library, also suggested student interest. While there were no statistically significant differences in median viewing or library access rates between the two intervention groups, the distribution of viewing patterns was shifted favourably. Those exposed to the more intensive intervention (class presentation) were significantly more likely to have reported watching at least one movie (97% vs. 81%; p = 0.033) or to having accessed at least one movie from the library (100% vs. 70%, p = 0.0001).</p> <p>Conclusions</p> <p>This pilot study found that the students had very positive attitudes towards viewing public health-related commercial movies. Movie access rates from the library were also favourable.</p

Effects of Antibiotics on the Growth and Physiology of Chlorophytes, Cyanobacteria, and a Diatom

The occurrence of antibiotics in surface waters has been reported worldwide with concentrations ranging from ng L−1 to low µg L−1 levels. During environmental risk assessments, effects of antibiotics on algal species are assessed using standard test protocols (e.g., the OECD 201 guideline), where the cell number endpoint is used as a surrogate for growth. However, the use of photosynthetic related endpoints, such as oxygen evolution rate, and the assessment of effects on algal pigments could help to inform our understanding of the impacts of antibiotics on algal species. This study explored the effects of three major usage antibiotics (tylosin, lincomycin, and trimethoprim) on the growth and physiology of two chlorophytes (Desmodesmus subspicatus and Pseudokirchneriella subcapitata), a cyanobacteria (Anabaena flos-aquae), and a diatom (Navicula pelliculosa) using a battery of parameters, including cell density, oxygen evolution rate, total chlorophyll content, carotenoids, and the irradiance–photosynthesis relationship. The results indicated that photosynthesis of chlorophytes was a more sensitive endpoint than growth (i.e., EC50 derived based on the effects of tylosin on the growth of D. subspicatus was 38.27 µmol L−1 compared with an EC50 of 17.6 µmol L−1 based on photosynthetic rate), but the situation was reversed when testing cyanobacteria and the diatom (i.e., EC50 derived based on the effects of tylosin on the growth of A. flos-aquae was 0.06 µmol L−1; EC50 0.33 µmol L−1 based on photosynthetic rate). The pigment contents of algal cells were affected by the three antibiotics for D. subspicatus. However, in some cases, pigment content was stimulated for P. subcapitata, N. pelliculosa, and A. flos-aquae. The light utilization efficiency of chlorophytes and diatom was decreased markedly in the presence of antibiotics. The results demonstrated that the integration of these additional endpoints into existing standardised protocols could provide useful insights into the impacts of antibiotics on algal species

Time Resolved Photoelectron Spectroscopy of Thioflavin T Photoisomerization: A Simulation Study

The excited state isomerization of thioflavin T (ThT) is responsible for the quenching of its fluorescence in a non-restricted environment. The fluorescence quantum yield increases substantially upon binding to amyloid fibers. Simulations reveal that the variation of the twisting angle between benzothiazole and benzene groups (ϕ(1)) is responsible for the sub-picosecond fluorescence quenching. The evolution of the twisting process can be directly probed by photoelectron emission with energies ε ≥ 1.0 eV before the molecule reaches the ϕ(1)-twisted configuration (~300 fs)

Heterogeneous treatment effects of therapeutic-dose heparin in patients hospitalized for COVID-19

Importance Randomized clinical trials (RCTs) of therapeutic-dose heparin in patients hospitalized with COVID-19 produced conflicting results, possibly due to heterogeneity of treatment effect (HTE) across individuals. Better understanding of HTE could facilitate individualized clinical decision-making. Objective To evaluate HTE of therapeutic-dose heparin for patients hospitalized for COVID-19 and to compare approaches to assessing HTE. Design, Setting, and Participants Exploratory analysis of a multiplatform adaptive RCT of therapeutic-dose heparin vs usual care pharmacologic thromboprophylaxis in 3320 patients hospitalized for COVID-19 enrolled in North America, South America, Europe, Asia, and Australia between April 2020 and January 2021. Heterogeneity of treatment effect was assessed 3 ways: using (1) conventional subgroup analyses of baseline characteristics, (2) a multivariable outcome prediction model (risk-based approach), and (3) a multivariable causal forest model (effect-based approach). Analyses primarily used bayesian statistics, consistent with the original trial. Exposures Participants were randomized to therapeutic-dose heparin or usual care pharmacologic thromboprophylaxis. Main Outcomes and Measures Organ support–free days, assigning a value of −1 to those who died in the hospital and the number of days free of cardiovascular or respiratory organ support up to day 21 for those who survived to hospital discharge; and hospital survival. Results Baseline demographic characteristics were similar between patients randomized to therapeutic-dose heparin or usual care (median age, 60 years; 38% female; 32% known non-White race; 45% Hispanic). In the overall multiplatform RCT population, therapeutic-dose heparin was not associated with an increase in organ support–free days (median value for the posterior distribution of the OR, 1.05; 95% credible interval, 0.91-1.22). In conventional subgroup analyses, the effect of therapeutic-dose heparin on organ support–free days differed between patients requiring organ support at baseline or not (median OR, 0.85 vs 1.30; posterior probability of difference in OR, 99.8%), between females and males (median OR, 0.87 vs 1.16; posterior probability of difference in OR, 96.4%), and between patients with lower body mass index (BMI 90% for all comparisons). In risk-based analysis, patients at lowest risk of poor outcome had the highest propensity for benefit from heparin (lowest risk decile: posterior probability of OR >1, 92%) while those at highest risk were most likely to be harmed (highest risk decile: posterior probability of OR <1, 87%). In effect-based analysis, a subset of patients identified at high risk of harm (P = .05 for difference in treatment effect) tended to have high BMI and were more likely to require organ support at baseline. Conclusions and Relevance Among patients hospitalized for COVID-19, the effect of therapeutic-dose heparin was heterogeneous. In all 3 approaches to assessing HTE, heparin was more likely to be beneficial in those who were less severely ill at presentation or had lower BMI and more likely to be harmful in sicker patients and those with higher BMI. The findings illustrate the importance of considering HTE in the design and analysis of RCTs. Trial Registration ClinicalTrials.gov Identifiers: NCT02735707, NCT04505774, NCT04359277, NCT0437258

Biomechanical Assessment of Three Rebar Tying Techniques

The National Institute for Occupational Safety and Health (NIOSH) conducted a study of ironworkers to evaluate their risk for developing back and hand injuries from hand-tying reinforcing steel bar and to investigate whether power tying tools can be an effective intervention for the prevention of work-related musculoskeletal disorders. A field investigation of biomechanical loading when using 3 techniques to tie together rebar was conducted. Researchers measured employees’ wrist and forearm movement with goniometers and videotaped and analyzed trunk postures. Manually tying rebar at ground level involved sustained deep trunk bending and rapid, repetitive, and forceful hand–wrist and forearm movements. Using a power tier significantly reduced the hand–wrist and forearm movements and allowed the ironworkers to use one free hand to support their trunk posture while tying. Adding an extension handle to the power tier allowed the ironworkers to tie rebar while standing erect, minimizing sustained trunk flexion