The human ovarian surface epithelium is an androgen responsive tissue

The pathogenesis of epithelial ovarian cancer remains unclear. From epidemiological studies raised levels of androgens have been implicated to increase the risk of developing the disease. The purpose of this study was to determine the responses of normal human ovarian surface epithelium to androgens. We have established primary cultures of human ovarian surface epithelium from patients undergoing oophorectomy for benign disease. Total RNA was isolated from these cultures and expression of mRNA encoding for the androgen receptor was demonstrated using reverse transcriptase polymerase chain reaction. The presence of androgen receptor in sections of normal ovary was also investigated using an antibody against androgen receptor. The effects of androgens on DNA synthesis and cell death were determined. Eight out of eight (100%) cultures expressed mRNA encoding the androgen receptor. The presence of androgen receptor in ovarian surface epithelium of sections of normal ovaries was demonstrated in all sections. Mibolerone, a synthetic androgen, caused a significant stimulation of DNA synthesis in 5 out of 9 (55%) cultures when used at a concentration of 1 nM. Mibolerone also caused a significant decrease in cell death in 2 out of 5 (40%) cultures tested. We have demonstrated that the ovarian surface epithelium is an androgen responsive tissue and that androgens can cause an increase in proliferation and a decrease in cell death. These findings have important implications for the pathophysiology of ovarian carcinogenesis

Composition Mixing during Blue Straggler Formation and Evolution

We use smoothed-particle hydrodynamics to examine differences between direct collisions of single stars and binary star mergers in their roles as possible blue straggler star formation mechanisms. We find in all cases that core helium in the progenitor stars is largely retained in the core of the remnant, almost independent of the type of interaction or the central concentration of the progenitor stars. We have also modelled the subsequent evolution of the hydrostatic remnants, including mass loss and energy input from the hydrodynamical interaction. The combination of the hydrodynamical and hydrostatic models enables us to predict that little mixing will occur during the merger of two globular cluster stars of equal mass. In contrast to the results of Proctor Sills, Bailyn, & Demarque (1995), we find that neither completely mixed nor unmixed models can match the absolute colors of observed blue stragglers in NGC 6397 at all luminosity levels. We also find that the color distribution is probably the crucial test for explanations of BSS formation - if stellar collisions or mergers are the correct mechanisms, a large fraction of the lifetime of the straggler must be spent away from the main sequence. This constraint appears to rule out the possibility of completely mixed models. For NGC 6397, unmixed models predict blue straggler lifetimes ranging from about 0.1 to 4 Gyr, while completely mixed models predict a range from about 0.6 to 4 Gyr.Comment: AASTeX, 28 pg., accepted for ApJ, also available at http://ucowww.ucsc.edu/~erics/bspaper.htm

Perinatal Loss at Term: The Role of Uteroplacental and Fetal Doppler Assessment.

OBJECTIVE: To examine the association of uterine artery (UtA) Doppler indices and cerebroplacental ratio (CPR) on perinatal outcome at term. METHODS: This retrospective cohort study conducted in a single tertiary referral centre included all singleton pregnancies undergoing ultrasound assessment in the third trimester, which subsequently delivered at term. Fetal biometry and Dopplers including the umbilical artery (UA), middle cerebral artery (MCA) and uterine artery were recorded. Data was corrected for gestational age and CPR was calculated as a ratio between the MCA pulsatility index (PI) and UA PI. Logistic regression analysis was conducted to examine for independent predictors of adverse perinatal outcome. RESULTS: The study included 7013 pregnancies; 12 were complicated by perinatal death. When compared to pregnancies resulting in live birth, pregnancies complicated by perinatal death had significantly more small for gestational age (SGA) infants (27.3% vs 5%, p = 0.001) and a higher incidence of low CPR (16.7% vs 4.5%, p = 0.041). A subgroup analysis comparing 1527 low risk pregnancies demonstrated that the UtA PI MoM, CPR <5(th) centile and estimated fetal weight (EFW) centile were all significantly associated with the risk of perinatal death at term (all p < 0.05). After adjusting for confounding variables, only EFW (OR 0.96, 95% CI 0.93-0.99; p = 0.003) and UtA PI MoM (OR 13.10, 95%CI 1.95-87.89; p = 0.008) remained independent predictors of perinatal death in the low risk cohort. CONCLUSION: High uterine artery PI at term is independently associated with increased risk of adverse perinatal outcome regardless of fetal size. These results suggest that perinatal mortality at term is related, not only to EFW and fetal redistribution (CPR), but also to indices of uterine perfusion

De‐novo abnormal uteroplacental circulation in third trimester: pregnancy outcome and pathological implications

Objective Hypertensive disorders of pregnancy (HDP) are associated with impaired placentation, as evidenced by abnormal uterine artery (UtA) Doppler. In normal pregnancy, mean UtA pulsatility index (PI) shows a progressive decline with gestational age (GA). However, previous studies have reported that a proportion of pregnancies demonstrate worsening UtA Doppler in later pregnancy. The aim of this study was to investigate the incidence of HDP according to the change in mean UtA‐PI between the second and third trimesters. Methods This was a retrospective cohort study of singleton pregnancies between March 1997 and March 2016 that underwent longitudinal UtA Doppler assessment in the second and third trimesters. All parameters were converted into centiles or multiples of the median (MoM), adjusting for GA. The study cohort was divided into two groups, according to change in mean UtA‐PI between the second and third trimesters (those with a decrease or no change and those with an increase). HDP included women who developed pre‐eclampsia and/or gestational hypertension. Logistic regression analysis was used to adjust for potential confounders. Results The analysis included 5887 pregnancies. The incidence of HDP was significantly higher in the group with increasing mean UtA‐PI compared with those without (7.9% vs 5.8%; P = 0.002). Logistic regression analysis demonstrated that both third‐trimester UtA‐PI MoM (odds ratio (OR), 7.35; 95% CI, 4.66–11.6; P < 0.001) and stable or decrease in UtA‐PI MoM between the second and third trimesters (OR, 0.43; 95% CI, 0.31–0.60; P < 0.001) were significant independent predictors for the development of HDP. Conclusion Worsening of UtA Doppler is associated with HDP, independent of the value recorded in the second trimester

Modeling the Geographic Distribution of \u3ci\u3eIxodes scapularis\u3c/i\u3e and \u3ci\u3eIxodes pacificus\u3c/i\u3e (Acari: Ixodidae) in the Contiguous United States

In addition to serving as vectors of several other human pathogens, the black-legged tick, Ixodes scapularis Say, and western black-legged tick, Ixodes pacificus Cooley and Kohls, are the primary vectors of the spirochete (Borrelia burgdorferi) that causes Lyme disease, the most common vector-borne disease in the United States. Over the past two decades, the geographic range of I. pacificus has changed modestly while, in contrast, the I. scapularis range has expanded substantially, which likely contributes to the concurrent expansion in the distribution of human Lyme disease cases in the Northeastern, North-Central and Mid-Atlantic states. Identifying counties that contain suitable habitat for these ticks that have not yet reported established vector populations can aid in targeting limited vector surveillance resources to areas where tick invasion and potential human risk are likely to occur. We used county-level vector distribution information and ensemble modeling to map the potential distribution of I. scapularis and I. pacificus in the contiguous United States as a function of climate, elevation, and forest cover. Results show that I. pacificus is currently present within much of the range classified by our model as suitable for establishment. In contrast, environmental conditions are suitable for I. scapularis to continue expanding its range into northwestern Minnesota, central and northern Michigan, within the Ohio River Valley, and inland from the southeastern and Gulf coasts. Overall, our ensemble models show suitable habitat for I. scapularis in 441 eastern counties and for I. pacificus in 11 western counties where surveillance records have not yet supported classification of the counties as established

The Structure of Isothermal, Self-gravitating Gas Spheres for Softened Gravity

A theory for the structure of isothermal, self-gravitating gas spheres in pressure equilibrium in a softened gravitational field is developed. The one parameter spline softening proposed by Hernquist & Katz (1989) is used. We show that the addition of this extra scale parameter implies that the set of equilibrium solutions constitute a one-parameter family, rather than the one and only one isothermal sphere solution for Newtonian gravity. We demonstrate the perhaps somewhat surprising result that for any finite choice of softening length and temperature, it is possible to deposit an arbitrarily large mass of gas in pressure equilibrium and with a non-singular density distribution inside of r_0 for any r_0 > 0. The theoretical predictions of our models are compared with the properties of the small, massive, quasi-isothermal gas clumps which typically form in numerical Tree-SPH simulations of 'passive' galaxy formation of Milky Way sized galaxies. We find reasonable agreement despite the neglect of rotational support in the models. We comment on whether the hydrodynamical resolution in our numerical simulation of galaxy formation is sufficient, and finally we conclude that one should be cautious, when comparing results of numerical simulations involving gravitational softening and hydrodynamical smoothing, with reality.Comment: 22 pages Latex + 12 figure

Multi-technique characterisation of MOVPE-grown GaAs on Si

The heterogeneous integration of III-V materials on a Si CMOS platform offers tremendous prospects for future high speed and low power logic applications. That said this integration generates immense scientific and technological challenges. In this work multi-technique characterisation is used to investigate properties of GaAs layers grown by Metal-Organic Vapour Phase Epitaxy (MOVPE) on Si substrates - (100) with 4⁰ offset towards - under various growth conditions. This being a crucial first step towards the production of III-V template layers with a relatively lower density of defects for selective epitaxial overgrowth of device quality material. The optical and structural properties of heteroepitaxial GaAs are first investigated by micro-Raman spectroscopy and photoluminescence and reflectance measurements. High-resolution X-ray diffraction (HR-XRD) is used to investigate structural properties. Advanced XRD techniques, including double-axis diffraction and X-ray crystallographic mapping are used to evaluate degrees of relaxation and distribution of the grain orientations in the epilayers, respectively. Results obtained from the different methodologies are compared in an attempt to understand growth kinetics of the materials system. The GaAs overlayer grown with annealing at 735⁰C following As predeposition at 500⁰C shows the best crystallinity. Close inspection confirms the growth of epitaxial GaAs preferentially oriented along (100) embedded in a highly-textured polycrystalline structure

Flow-History-Dependent Behavior in Entangled Polymer Melt Flow with Multiscale Simulation

Polymer melts represent the flow-history-dependent behavior. To clearly show this behavior, we have investigated flow behavior of an entangled polymer melt around two cylinders placed in tandem along the flow direction in a two dimensional periodic system. In this system, the polymer states around a cylinder in downstream side are different from the ones around another cylinder in upstream side because the former ones have a memory of a strain experienced when passing around the cylinder in upstream side but the latter ones do not have the memory. Therefore, the shear stress distributions around two cylinders are found to be different from each other. Moreover, we have found that the averaged flow velocity decreases accordingly with increasing the distance between two cylinders while the applied external force is constant. While this behavior is consistent with that of the Newtonian fluid, the flow-history-dependent behavior enhances the reduction of the flow resistance.Comment: 6 pages, 3 figures, Proceedings of 5th International Mini-Symposium on Liquid

Investigating the association between children’s screen media exposure and vocabulary size in the UK

Children are growing up in a digital age with increasing exposure to television and touchscreen devices. We tested whether exposure to screen media is associated with children’s early language development. One hundred and thirty-one highly educated caregivers of UK children aged 6–36 months completed a media exposure questionnaire and vocabulary measure. 99% of children were read to daily, 82% watched television, and 49% used mobile touchscreen devices daily. Regression analyses revealed that time spent reading positively predicted vocabulary comprehension and production scores at 6–18 months, but time spent engaging with television or mobile touchscreen devices was not associated with vocabulary scores. Critically, correlations revealed that time spent reading or engaging with other non-screen activities was not offset by time spent engaging with television or mobile touchscreen devices. Thus, there was no evidence to suggest that screen media exposure adversely influenced vocabulary size in our sample of highly educated families with moderate media use