Vacancy assisted arsenic diffusion and time dependent clustering effects in silicon

We present results of kinetic lattice Monte Carlo (KLMC) simulations of substitutional arsenic diffusion in silicon mediated by lattice vacancies. Large systems are considered, with 1000 dopant atoms and long range \textit{ab initio} interactions, to the 18th nearest lattice neighbor, and the diffusivity of each defect species over time is calculated. The concentration of vacancies is greater than equilibrium concentrations in order to simulate conditions shortly after ion implantation. A previously unreported time dependence in the applicability of the pair diffusion model, even at low temperatures, is demonstrated. Additionally, long range interactions are shown to be of critical importance in KLMC simulations; when shorter interaction ranges are considered only clusters composed entirely of vacancies form. An increase in arsenic diffusivity for arsenic concentrations up to $10^{19} \text{cm}^{-3}$ is observed, along with a decrease in arsenic diffusivity for higher arsenic concentrations, due to the formation of arsenic dominated clusters. Finally, the effect of vacancy concentration on diffusivity and clustering is studied, and increasing vacancy concentration is found to lead to a greater number of clusters, more defects per cluster, and a greater vacancy fraction within the clusters.Comment: 22 pages, 16 figure

Structural and Functional Alterations in The Zona Fasciculata of The Rat Adrenal Cortex in Obstructive Jaundice

This study investigated the effect of experimentally-induced cholestasis in the rat on the structure and function of the zona fasciculata, the glucocorticoid secretory region of the adrenal cortex. Wistar-Furth rats (200-250g) were assigned to three groups: bile duct ligated (BDL), Sham operated (Sham) and unmodified normal control (NC). On day 14, serum bilirubin and liver histology were performed to confirm cholestasis in BDL animals together with basal 24 hour 17-hydroxycorti-costeroid excretion, adrenal histology and zona fasciculata ultrastructure in all experimental groups. Following this laparotomy, structural and functional studies were repeated on day 15 to evaluate the response of the gland to surgically induced stress. Basal 24 hr. 17-hydroxycorticoid steroid excretion was elevated in BDL animals (26.9 ±3.2 μ g/24 hr) with respect to Sham (10.4 ± 2.3) and NC groups (13.5 ± 3.2) (p <0.05). Adrenal histology and ultrastructural studies demonstrated excessive accumulation of vesicles laden with glucocorticoid biogenic precursors. Following surgical stress 24 hr 17 OH corticosteroid excretion increased in all groups: BDL (31.0 ± 3.0 μg/24 hr) vs Sham (15.6 ± 1.8) and NC (14.5 ± 2.4) Moderate alterations in zona fasciculata architecture were seen following surgery in all groups. Cholestasis induces overactivity of the zona fasciculata of the adrenal cortex, and may modify the normal metabolic responses to surgical and other stresses

Parasite Dynamics in Untreated Horses Through One Calendar Year

Background: Horses are host to a plethora of parasites. Knowledge of the seasonality of parasite egg shedding and transmission is important for constructing parasite control programs. However, studies describing these patterns are sparse, and have largely been conducted only in the United Kingdom. This study evaluated strongylid egg shedding patterns and transmission dynamics of Strongylus vulgaris in naturally infected and untreated mares and foals through one calendar year in Kentucky, USA. The study also investigated the existence of a peri-parturient rise (PPR) in strongylid egg counts in foaling mares and collected information about Strongyloides westeri and Parascaris spp. in the foals. Methods: This study was conducted from January to December 2018. A herd of 18 mares, one stallion, and 14 foals born in 2018 were followed throughout the year. Sera and feces were collected biweekly from all horses, and worm burdens enumerated in 13 foals at necropsy. An S. vulgaris ELISA antibody test was run on all serum samples. Fecal egg counts were determined for all horses, and coproculture and qPCR assay were employed to test for the presence of S. vulgaris in the mature horses. Data were analyzed using the proc glimmix procedure in the SAS 9.4 software program. Results: We found a general lack of seasonality in strongylid egg shedding throughout the year among the mature horses, and no PPR was demonstrated. Shedding of S. vulgaris eggs displayed a higher abundance during the spring, but fndings were variable and not statistically signifcant. Anti-S. vulgaris antibody concentrations did not display signifcant fuctuations in the mature horses, but evidence of passive transfer of antibodies to the foals was demonstrated, and foals assumed their own production of antibodies starting at approximately 20 weeks of age. Overall, colts shed higher numbers of strongylid, ascarid, and S. westeri eggs than fllies. Conclusions: This study demonstrated a lack of seasonality in strongylid egg shedding for the study population, which is in stark contrast to previous studies conducted elsewhere. This strongly suggests that more studies should be done investigating these patterns under diferent climatic condition

Muscular Performance and Neuromuscular Fatigue are not Sex-Dependent During Low-Load Fatiguing Bilateral Leg Extension Exercise

Purpose. This study examined the sex-related differences in muscular performance and neuromuscular (electromyographic [EMG] and mechanomyographic [MMG] amplitude [AMP] and mean power frequency [MPF]) responses during fatiguing leg extension repetitions performed at the critical load (CL). Methods. Eleven men and nine women completed one-repetition maximum (1RM) testing, repetitions to failure at 50, 60, 70, and 80% 1RM to determine CL, and repetitions to failure at CL, on separate days. The EMG and MMG, AMP and MPF signals and number of repetitions completed were recorded. Results. There were no sex-dependent responses in the %1RM that corresponded to, the number of repetitions completed at, or the neuromuscular responses during repetitions performed to failure at CL. There were time-dependent responses in EMG AMP from 25-100% of total repetitions completed, respectively. The EMG MPF and MMG MPF demonstrated fatigue-induced decreases from 50-100% and at 100% of total repetitions completed, respectively. There was no change over time for MMG AMP. Conclusions. These findings indicated men and women responded similarly to leg extension exercise performed at the CL. Further, sex-dependent responses to fatiguing exercise may be related to the amount of active muscle mass engaged in exercise and the corresponding afferent feedback that influences peripheral fatigue and central drive during fatiguing tasks

Geochemical proxies of North American freshwater routing during the Younger Dryas cold event

Author Posting. © The Authors, 2006. This is the author's version of the work. It is posted here by permission of National Academy of Sciences for personal use, not for redistribution. The definitive version was published in Proceedings of the National Academy of Sciences 104 (2007): 6556-6561, doi:10.1073/pnas.0611313104.The Younger Dryas cold interval represents a time when much of the Northern Hemisphere cooled from ~12.9 to 11.5 kiloyears before present. The cause of this event, which has long been viewed as the canonical example of abrupt climate change, was initially attributed to the routing of freshwater to the St. Lawrence River with an attendant reduction in Atlantic meridional overturning circulation. However, this mechanism has recently been questioned because current proxies and dating techniques have been unable to confirm that eastward routing with an increase in freshwater flux occurred during the Younger Dryas. Here we use new geochemical proxies (ΔMg/Ca, U/Ca & 87Sr/86Sr) measured in planktonic foraminifera at the mouth of the St. Lawrence Estuary as tracers of freshwater sources to further evaluate this question. Our proxies, combined with planktonic δ18Oseawater and δ13C, confirm that routing of runoff from western Canada to the St. Lawrence River occurred at the start of the Younger Dryas, with an attendant increase in freshwater flux of 0.06 ± 0.02 Sverdrup (1 Sverdrup (Sv) = 106 m3 s-1). This base discharge increase is sufficient to have reduced Atlantic meridional overturning circulation and caused the Younger Dryas cold interval. In addition, our data indicate subsequent fluctuations in the freshwater flux to the St. Lawrence River of ~0.06 to 0.12 Sv, thus explaining the variability in the overturning circulation and climate during the Younger Dryas.This research was funded by the NSF Paleoclimate Program (P.U.C.) and the NSF (G.P.K.)

Parasite Dynamics in Untreated Horses through One Calendar Year

BACKGROUND: Horses are host to a plethora of parasites. Knowledge of the seasonality of parasite egg shedding and transmission is important for constructing parasite control programs. However, studies describing these patterns are sparse, and have largely been conducted only in the United Kingdom. This study evaluated strongylid egg shedding patterns and transmission dynamics of Strongylus vulgaris in naturally infected and untreated mares and foals through one calendar year in Kentucky, USA. The study also investigated the existence of a peri-parturient rise (PPR) in strongylid egg counts in foaling mares and collected information about Strongyloides westeri and Parascaris spp. in the foals. METHODS: This study was conducted from January to December 2018. A herd of 18 mares, one stallion, and 14 foals born in 2018 were followed throughout the year. Sera and feces were collected biweekly from all horses, and worm burdens enumerated in 13 foals at necropsy. An S. vulgaris ELISA antibody test was run on all serum samples. Fecal egg counts were determined for all horses, and coproculture and qPCR assay were employed to test for the presence of S. vulgaris in the mature horses. Data were analyzed using the proc glimmix procedure in the SAS 9.4 software program. RESULTS: We found a general lack of seasonality in strongylid egg shedding throughout the year among the mature horses, and no PPR was demonstrated. Shedding of S. vulgaris eggs displayed a higher abundance during the spring, but findings were variable and not statistically significant. Anti-S. vulgaris antibody concentrations did not display significant fluctuations in the mature horses, but evidence of passive transfer of antibodies to the foals was demonstrated, and foals assumed their own production of antibodies starting at approximately 20 weeks of age. Overall, colts shed higher numbers of strongylid, ascarid, and S. westeri eggs than fillies. CONCLUSIONS: This study demonstrated a lack of seasonality in strongylid egg shedding for the study population, which is in stark contrast to previous studies conducted elsewhere. This strongly suggests that more studies should be done investigating these patterns under different climatic conditions

Functional characterization of a panel of high-grade serous ovarian cancer cell lines as representative experimental models of the disease.

Genomic analysis of ovarian cancer cell lines has revealed a panel that best represents the most common ovarian cancer subtype, high-grade serous ovarian cancer (HGSOC). However, these HGSOC-like cell lines have not been extensively applied by ovarian cancer researchers to date, and the most commonly used cell lines in the ovarian cancer field do not genetically resemble the major clinical type of the disease. For the HGSOC-like lines to serve as suitable models, they need to be characterized for common functional assays. To achieve that objective, we systematically studied a panel of HGSOC cells CAOV3, COV362, Kuramochi, OVCAR4, OVCAR5, OVCAR8, OVSAHO and SNU119 for migration, invasion, proliferation, clonogenicity, EMT phenotype and cisplatin resistance. They exhibited a range of efficacies and OVCAR5, OVCAR8 and Kuramochi were the most aggressive. SNU119 and OVSAHO cells demonstrated the lowest functional activities. Wide differences in expression of EMT markers were observed between cell lines. SNU119 were the most epithelial and OVCAR8 had the most mesenchymal phenotype. COV362 was the most resistant to cisplatin while CAOV3 was the most sensitive. Taken together, our systematic characterization represents a valuable resource to help guide the application of HGSOC cells by the cancer research community

Effects of a 6-week Low-Carbohydrate High-Fat Diet on Lipid Profiles in Competitive Recreational Distance Runners

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