CT measures of lumbosacral paraspinal muscle size are not correlated with CT measures of lumbosacral stability in military working Labrador Retrievers.

Management of degenerative lumbosacral stenosis in military working dogs more frequently utilizes core conditioning exercise programs. Future research on the effectiveness of these programs may benefit from an improved understanding of relationships between paraspinal muscle size and lumbosacral stability. The aim of this retrospective, secondary analysis, cross-sectional study was to test the following hypotheses related to CT measures: (a) transverse paraspinal muscle area ratios differ between hip flexion and extension, (b) lumbosacral angle and lumbosacral range of motion differ by lumbosacral angle measurement technique, and (c) transverse paraspinal muscle area ratios are correlated with CT measures of lumbosacral stability (parasagittal and parasagittal oblique foraminal area changes) regardless of hip position and with lumbosacral range of motion within each hip position. Lumbosacral CT scans in hip flexion and extension were retrieved from a previous prospective study of military working Labrador Retrievers. A single observer performed triplicate measurements of transverse paraspinal muscle area ratios, parasagittal foraminal area, and parasagittal oblique foraminal area for each hip position and another observer independently performed triplicate measurements of lumbosacral angle and lumbosacral range of motion at L7-S1 using two published techniques. Thirty-nine dogs were analyzed and significant differences were identified between hip flexion and extension for all mean transverse paraspinal muscle area ratio values (P ≤ .05). Mean lumbosacral angles also significantly differed between the published techniques in both hip flexion and extension. When comparing mean lumbosacral range of motion values, one of the published techniques produced significantly smaller values. No significant correlation was found between transverse paraspinal muscle area ratios and parasagittal foraminal area changes, parasagittal oblique foraminal area changes, or lumbosacral range of motion. These results should be considered when designing studies using these CT measures in military working dogs.

Factors influencing persistence of a threatened amphibian in restored wetlands despite severe population decline during climate change driven weather extremes.

Biodiversity is in global decline during the Anthropocene. Declines have been caused by multiple factors, such as habitat removal, invasive species, and disease, which are often targets for conservation management. However, conservation interventions are under threat from climate change induced weather extremes. Weather extremes are becoming more frequent and devastating and an example of this was the 2019/2020 Australian drought and mega-fires. We provide a case study the impacts of these extreme weather events had on a population of the threatened frog Litoria aurea that occurs in a constructed habitat which was designed to reduce the impact of introduced fish and chytrid-induced disease. We aimed to determine what factors influenced persistence so that the design of wetlands can be further optimised to future-proof threatened amphibians. We achieved this with 4 years (2016-2020) of intensive capture-recapture surveys during austral spring and summer across nine wetlands (n = 94 repeat surveys). As hypothesized, drought caused a sharp reduction in population size, but persistence was achieved. The most parsimonious predictor of survival was an interaction between maximum air temperature and rainfall, indicating that weather extremes likely caused the decline. Survival was positively correlated with wetland vegetation coverage, positing this is an important feature to target to enhance resilience in wetland restoration programs. Additionally, the benefits obtained from measures to reduce chytrid prevalence were not compromised during drought, as there was a positive correlation between salinity and survival. We emphasize that many species may not be able to persist under worse extreme weather scenarios. Despite the potential for habitat augmentation to buffer effects of extreme weather, global action on climate change is needed to reduce extinction risk. Supplementary Information: The online version contains supplementary material available at 10.1007/s10531-022-02387-9.

Lifetime Allergy Symptoms in IgG4-Related Disease: A Case-Control Study.

OBJECTIVE: The etiology of IgG4-related disease (IgG4-RD) is unknown, and there has been controversy over the significance of allergic conditions in IgG4-RD. We examined the prevalence of lifetime allergy symptoms in IgG4-RD and the association between these and IgG4-RD. METHODS: We identified IgG4-RD patients and non-IgG4-RD controls without autoimmune conditions seen at a single center. IgG4-RD patients were classified using the American College of Rheumatology/European Alliance of Associations for Rheumatology classification criteria. Allergy symptoms were ascertained by questionnaire. We assessed the association of IgG4-RD features with allergy symptoms. We compared the proportion of cases and controls with allergy symptoms using conditional logistic regression to estimate odds ratios (ORs) and 95% confidence intervals (95% CIs) after matching cases and controls 1:1 by age and sex. RESULTS: Lifetime allergy symptoms were reported by 165 (71%) of 231 IgG4-RD patients. Aeroallergen symptoms were most commonly reported (n = 135, 58%), followed by skin allergy symptoms (n = 97, 42%) and food allergy symptoms (n = 47, 20%). IgG4-RD cases with a history of allergy symptoms were more likely to have head and neck involvement (OR 2.0 [95% CI 1.1-3.6]) and peripheral eosinophilia (OR 3.3 [95% CI 1.2-9.0]) than those without allergy symptoms. The prevalence of any allergy symptoms was similar between cases and controls (OR 0.7 [95% CI 0.4-1.1]); this remained consistent after stratifying by head and neck involvement. CONCLUSION: Lifetime allergy symptoms are common in IgG4-RD but are not reported more often in IgG4-RD compared to non-IgG4-RD patients without autoimmune conditions. These findings suggest that allergies are not uniquely associated with the pathogenesis or presentation of IgG4-RD.

Micellization behavior of coarse grained surfactant models.

We use molecular dynamics simulations over microsecond time scales to study the micellization behavior of recently proposed continuum-space, coarse grained surfactant models. In particular, we focus on the MARTINI model by Marrink et al. [J. Phys. Chem. B 111, 7812 (2007)] and a model by Shinoda et al. [Soft Matter 4, 2454 (2008)]. We obtain the critical micelle concentration (cmc) and equilibrium aggregate size distributions at low surfactant loadings. We present evidence justifying modest extrapolations for determining the cmc at low temperatures, where significant sampling difficulties remain. The replica exchange method provides only modest improvements of sampling efficiency for these systems. We find that the two coarse grained models significantly underpredict experimental cmc near room temperature for zwitterionic surfactants, but are closer to measured values for nonionic ones. The aggregation numbers for both zwitterionic and nonionic surfactants are near those observed experimentally, but the temperature dependence of the cmc is incorrect in both cases, because of the use of an unstructured solvent. Possible refinements to the models to bring them into quantitative agreement with experiment are discussed.

Preparing health professions students to lead change.

PURPOSE: Health care systems increasingly demand health professionals who can lead interdisciplinary teams. While physicians recognize the importance of leadership skills, few receive formal instruction in this area. This paper aims to describe how the Student Leadership Committee (SLC) at the Harvard Medical School Center for Primary Care responded to this need by creating a leadership curriculum for health professions students. DESIGN/METHODOLOGY/APPROACH: The SLC designed an applied longitudinal leadership curriculum and taught it to medical, dentistry, nursing, public health and business students during monthly meetings over two academic years. The perceptions of the curriculum were assessed via a retrospective survey and an assessment of team functioning. FINDINGS: Most teams met their project goals and students felt that their teams were effective. The participants reported increased confidence that they could create change in healthcare and an enhanced desire to hold leadership positions. The sessions that focused on operational skills were especially valued by the students. PRACTICAL IMPLICATIONS: This case study presents an effective approach to delivering leadership training to health professions students, which can be replicated by other institutions. SOCIAL IMPLICATIONS: Applied leadership training empowers health professions students to improve the health-care system and prepares them to be more effective leaders of the future health-care teams. The potential benefits of improved health-care leadership are numerous, including better patient care and improved job satisfaction among health-care workers. ORIGINALITY/VALUE: Leadership skills are often taught as abstract didactics. In contrast, the approach described here is applied to ongoing projects in an interdisciplinary setting, thereby preparing students for real-world leadership positions.

Atomistic simulations of micellization of sodium hexyl, heptyl, octyl, and nonyl sulfates.

Molecular dynamics simulations have been used to study the micellization behavior of atomistic models for sodium alkyl sulfates in explicit water. A major finding of the present work is the observation of a strong dependence of free surfactant concentration on overall surfactant concentration, that has not been reported previously and that is key to comparing simulation results for the critical micelle concentration (CMC) to experimental data. The CMC and aggregate size distributions were obtained for alkyl tail lengths from six to nine at temperatures from 268 to 363 K, from 400 ns simulations covering a number of surfactant and water model combinations. The free surfactant concentration is much lower than the critical micelle concentration for strongly micellizing systems at the relatively high concentrations accessible by simulations. Thus, counterion association must be accounted for in determining the CMC from the raw simulation data. Simulation results are in qualitative agreement with experimental trends for aggregate size and CMC as functions of alkyl tail length and temperature.

Implicit-solvent models for micellization: nonionic surfactants and temperature-dependent properties.

We have investigated micellization properties of surfactants using a recently developed implicit-solvent model and grand canonical Monte Carlo simulations. The original model had been parametrized for ionic surfactants at a single temperature; it is extended here to aqueous solutions of nonionic surfactants and given an explicit temperature dependence. Specifically, we have developed an implicit-solvent model of polyethylene glycol (PEG) surfactants and obtained the critical micelle concentrations (cmc's) and micellar aggregation numbers at low surfactant loadings. Various combinations of ethoxy and hydrocarbon tail segments were investigated in order to explore the predictive capabilities of the model. For the temperature dependence of the micellization properties, we have utilized thermodynamic approaches to quantify the hydrophobic attraction at temperatures ranging from 280 to 365 K. The temperature dependence of the cmc and the aggregate sizes were obtained for various ionic and nonionic surfactants, specifically sodium dodecyl sulfate, dodecyltrimethylammonium bromide and chloride, and PEG surfactants. For all systems studied, the model yields cmc and aggregation sizes that are in near-quantitative agreement with experimental results.