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For many reptile species, adequate ultraviolet B (UVB) radiation is essential for proper calcium metabolism. In this study, the effects of UVB radiation on calcium metabolism were evaluated in green sea turtles (Chelonia mydas). 25-Hydroxyvitamin D, parathyroid hormone (PTH), and ionized calcium (iCa) were measured in juvenile (n = 18, 9 indoor, 9 outdoor) and adult (n = 8, 4 indoor, 4 outdoor) turtles. All animals were fed an identical diet. Outdoor animals had access to unfiltered sunlight, whereas indoor animals were housed under artificial lighting without UVB. Mean values for 25-hydroxyvitamin D for the outdoor and indoor groups were 34.33 ± 7.98 nmol/L and 7.11 ± 1.69 nmol/L for juveniles and 73.25 ± 30.34 nmol/L and 14.0 ± 11.52 nmol/L for adults respectively. Mean values for iCa for the outdoor and indoor groups were 0.98 ± 0.07 mmol/L and 0.99 ± 0.06 mmol/L for juveniles and 1.18 ± 0.22 mmol/L and 0.97 ± 0.18 mmol/L for adults respectively. UVB exposure (P < 0.001) and age (P < 0.001) had a significant effect on 25-hydroxyvitamin D as well as a significant interaction between the two variables (P = 0.008), with highest values in adult outdoor turtles. There was a significant interaction between age group and UVB status for iCa (P = 0.036), with greater values in older outdoor turtles. 25-Hydroxyvitamin D and total calcium were positively correlated, rs = 0.39, P = 0.042. iCa and calcium-to-phosphorus ratios were also positively correlated, rs = 0.42, P = 0.027. These results suggest that UVB exposure is an important source of 25-hydroxyvitamin D for green sea turtles and has significant effects on calcium metabolism in this species. PTH values in this study were near the minimum limits of detection and suggest that current mammalian-based PTH assays are not valid for reptiles.

Despite extensive literature examining American horseshoe crab physiology, there are comparatively few publications addressing their medical care. Establishing anesthesia protocols for horseshoe crabs is integral to limiting the potential stress and pain associated with invasive procedures and for advancing euthanasia techniques. The objective of this study was to compare the effects of two immersion anesthetics, tricaine methanesulfonate (MS-222) at 1 g/L (buffered with sodium carbonate) and 2-phenoxyethanol (2-PE) at 2 mL/L, on horseshoe crabs. Twenty horseshoe crabs were assigned to one of two anesthetic treatment groups and individually anesthetized in natural seawater. Water quality, cardiac contractility, and hemolymph gas analytes were measured prior to anesthesia and at 30 min Animals were monitored via heart rate, gilling rate, and sedation score every 5 min until recovered. Transcarapacial ultrasonography was used to obtain heart rate, gilling rate, and percent fractional shortening. Light or surgical anesthesia was produced in 10/10 animals in the 2-PE group and 8/10 animals in the MS-222 group. There was no significant difference in sedation scores, induction time (median 15 min), or recovery time (median 20.5 min). Gilling rate and cardiac contractility decreased during anesthesia, whereas heart rate did not. Hemolymph pH and pO2 were not different among treatment groups or time points. Baseline pCO2 was higher than pCO2 at 30 min for both groups but significantly elevated only in the MS-222 group. This is attributed to increased activity during the handling of awake animals. Invasive blood pressure obtained via cardiac catheterization in two animals was markedly decreased during surgical anesthesia. In conclusion, 2-PE and MS-222 provided effective anesthesia with clinically useful induction and recovery times. 2-PE provided a subjectively more reliable and smoother anesthesia compared to MS-222.

Carnivorous reptiles are not usually thought of as being prone to metabolic bone disorders. A constant diet lacking in calcium or bone and/or high in phosphorus or low in vitamin D3 can lead to this nutritional disorder in certain situations. Nile monitor lizards are carnivorous lizards native to Africa and common in the pet trade and as display animals in zoos. They normally consume whole vertebrate prey but will readily take muscle and organ offerings. This is a case of a Nile monitor that suffered fibrous osteodystrophy and chondroid metaplasia after being fed mostly muscle tissue for over two years. Once the diet was corrected the clinical signs resolved.

Goldfish that have been repeatedly exposed to tricaine methanesulfonate (MS-222) require greater concentration of the drug to attain equivalent planes of anesthesia, but the mechanism for this increased anesthetic need is unknown. Minimum anesthetic concentration (MAC) is a commonly used method with which to compare anesthetics. It was hypothesized that fish exposed to MS-222 daily would have an increased MAC. It was also hypothesized that fish exposed daily to MS-222 would develop histomorphologic changes to their gills to explain the increasing demand. Forty-nine Serasa comet goldfish were enrolled and were divided into three populations (n = 15, n = 15, and n = 19). In trial 1, using an up–down method, MAC was determined daily after 4 min of exposure to MS-222 for which the starting concentration was 160 mg/L. In trial 2, MAC was determined following 2 min of exposure to MS-222 for which the starting concentration was 260 mg/L. In trial 3, four naive fish were euthanatized and gills collected for histology and electron microscopy (EM). The remaining fish were exposed to MS-222 daily for 4 wk. Four fish were euthanatized and their gills submitted for similar examination at 2 wk and 4 wk. MAC for fish exposed to MS-222 for 4 min increased from 120 to 160 mg/L. The regression line had a slope of 1.51 ± 0.26 (R2 = 0.65; P < 0.0001). MAC for fish exposed to MS-222 for 2 min increased from 210 pmm to 220 mg/L; the regression line had a slope of 0.52 ± 0.38 (R2 = 0.12; P = 0.2). Histologic and EM examination of gills did not show morphologic changes indicative of a reaction to MS-222. Goldfish in this study had an increased requirement for MS-222 following daily exposure for 4 min but not following daily exposure for 2 min at a higher concentration. The cause of this increased anesthetic need is not related to morphologic changes to the gills.

Investor-State Dispute Settlement (ISDS) is a provision in Bilateral Investment Treaties (BITs) and other international investment agreements that allows investors to enter arbitration with states over treaty breaches. This report is an empirical review of ISDS, based on the record of disputes under existing investment treaties.

\"Technology has introduced dramatic new efficiencies to supply chain design, management, and control--but only to those who can open their minds to these new methods and strategies. This book presents innovative articles from eighteen of today's top young Ph.D. scholars, each based on discussions at the 2000 Frank Batten Young Leaders Forum of the College of William and Mary.

University students are increasingly recognized as a vulnerable population, suffering from higher levels of anxiety, depression, substance abuse, and disordered eating compared to the general population. Therefore, when the nature of their educational experience radically changes-such as sheltering in place during the COVID-19 pandemic-the burden on the mental health of this vulnerable population is amplified. The objectives of this study are to 1) identify the array of psychological impacts COVID-19 has on students, 2) develop profiles to characterize students' anticipated levels of psychological impact during the pandemic, and 3) evaluate potential sociodemographic, lifestyle-related, and awareness of people infected with COVID-19 risk factors that could make students more likely to experience these impacts. Cross-sectional data were collected through web-based questionnaires from seven U.S. universities. Representative and convenience sampling was used to invite students to complete the questionnaires in mid-March to early-May 2020, when most coronavirus-related sheltering in place orders were in effect. We received 2,534 completed responses, of which 61% were from women, 79% from non-Hispanic Whites, and 20% from graduate students. Exploratory factor analysis on close-ended responses resulted in two latent constructs, which we used to identify profiles of students with latent profile analysis, including high (45% of sample), moderate (40%), and low (14%) levels of psychological impact. Bivariate associations showed students who were women, were non-Hispanic Asian, in fair/poor health, of below-average relative family income, or who knew someone infected with COVID-19 experienced higher levels of psychological impact. Students who were non-Hispanic White, above-average social class, spent at least two hours outside, or less than eight hours on electronic screens were likely to experience lower levels of psychological impact. Multivariate modeling (mixed-effects logistic regression) showed that being a woman, having fair/poor general health status, being 18 to 24 years old, spending 8 or more hours on screens daily, and knowing someone infected predicted higher levels of psychological impact when risk factors were considered simultaneously. Inadequate efforts to recognize and address college students' mental health challenges, especially during a pandemic, could have long-term consequences on their health and education.

Access to efficient enzymatic channeling is desired for improving all manner of designer biocatalysis. We demonstrate that enzymes constituting a multistep cascade can self-assemble with nanoparticle scaffolds into nanoclusters that access substrate channeling and improve catalytic flux by orders of magnitude. Utilizing saccharification and glycolytic enzymes with quantum dots (QDs) as a model system, nanoclustered-cascades incorporating from 4 to 10 enzymatic steps are prototyped. Along with confirming channeling using classical experiments, its efficiency is enhanced several fold more by optimizing enzymatic stoichiometry with numerical simulations, switching from spherical QDs to 2-D planar nanoplatelets, and by ordering the enzyme assembly. Detailed analyses characterize assembly formation and clarify structure-function properties. For extended cascades with unfavorable kinetics, channeled activity is maintained by splitting at a critical step, purifying end-product from the upstream sub-cascade, and feeding it as a concentrated substrate to the downstream sub-cascade. Generalized applicability is verified by extending to assemblies incorporating other hard and soft nanoparticles. Such self-assembled biocatalytic nanoclusters offer many benefits towards enabling minimalist cell-free synthetic biology. Channeling between enzymes is a uniquely nanoscale phenomenon that can improve multienzymatic reaction rates. Here, the authors demonstrate that multistep enzyme cascades can self-assemble with nanoparticles into nanoclusters that access channeling and improve the underlying catalytic flux by several fold.

Trials of the efficacy and safety of endovascular thrombectomy in patients with large ischemic strokes have been carried out in limited populations. We performed a prospective, randomized, open-label, adaptive, international trial involving patients with stroke due to occlusion of the internal carotid artery or the first segment of the middle cerebral artery to assess endovascular thrombectomy within 24 hours after onset. Patients had a large ischemic-core volume, defined as an Alberta Stroke Program Early Computed Tomography Score of 3 to 5 (range, 0 to 10, with lower scores indicating larger infarction) or a core volume of at least 50 ml on computed tomography perfusion or diffusion-weighted magnetic resonance imaging. Patients were assigned in a 1:1 ratio to endovascular thrombectomy plus medical care or to medical care alone. The primary outcome was the modified Rankin scale score at 90 days (range, 0 to 6, with higher scores indicating greater disability). Functional independence was a secondary outcome. The trial was stopped early for efficacy; 178 patients had been assigned to the thrombectomy group and 174 to the medical-care group. The generalized odds ratio for a shift in the distribution of modified Rankin scale scores toward better outcomes in favor of thrombectomy was 1.51 (95% confidence interval [CI], 1.20 to 1.89; P<0.001). A total of 20% of the patients in the thrombectomy group and 7% in the medical-care group had functional independence (relative risk, 2.97; 95% CI, 1.60 to 5.51). Mortality was similar in the two groups. In the thrombectomy group, arterial access-site complications occurred in 5 patients, dissection in 10, cerebral-vessel perforation in 7, and transient vasospasm in 11. Symptomatic intracranial hemorrhage occurred in 1 patient in the thrombectomy group and in 2 in the medical-care group. Among patients with large ischemic strokes, endovascular thrombectomy resulted in better functional outcomes than medical care but was associated with vascular complications. Cerebral hemorrhages were infrequent in both groups. (Funded by Stryker Neurovascular; SELECT2 ClinicalTrials.gov number, NCT03876457.).

The conversion of photoexcitations into charge carriers in organic solar cells is facilitated by the dissociation of excitons at the donor/acceptor interface. The ultrafast timescale of charge separation demands sophisticated theoretical models and raises questions about the role of coherence in the charge-transfer mechanism. Here, we apply two-dimensional electronic spectroscopy to study the electron transfer process in poly(3-hexylthiophene)/PCBM (P3HT/PCBM) blends. We report dynamics maps showing the pathways of charge transfer that clearly expose the significance of hot electron transfer. During this ultrafast electron transfer, vibrational coherence is directly transferred from the P3HT exciton to the P3HT hole polaron in the crystalline domain. This result reveals that the exciton converts to a hole with a similar spatial extent on a timescale far exceeding other photophysical dynamics including vibrational relaxation. Dissociation of excitons at the donor/acceptor interface in organic solar cells occurs on fast timescales. Here, the authors apply two-dimensional electronic spectroscopy to study the electron transfer process in a polymer blend, reporting dynamic maps for the charge-transfer pathways.