Manganese causes differential regulation of glutamate transporter (GLAST) taurine transporter and metallothionein in cultured rat astrocytes.

, it is likely that in pathological conditions it can reach 100-500 μM. Amino acid (e.g. aspartate, glutamate, taurine), as well as divalent metal (e.g. zinc, manganese) concentrations are regulated by astrocytes in the brain. Recently, it has been reported that cultured rat primary astrocytes exposed to Mn displayed decreased glutamate uptake, thereby, increasing the excitotoxic potential of glutamate. Since the neurotoxic mechanism(s) Mn employs in terms of glutamate metabolism is unknown, a primary goal of this study was to link altered glutamate uptake in Mn exposed astrocytes to alterations in glutamate transporter message. Further, we wanted to examine the gene expression of metallothionein (MT) and taurine transporter (tau-T) as markers of Mn exposure. Glutamate uptake was decreased by nearly 40% in accordance with a 48% decrease in glutamate/aspartate transporter (GLAST) mRNA. Taurine uptake was unaffected by Mn exposure even though tau-T mRNA increased by 123%. MT mRNA decreased in these Mn exposed astrocytes possibly due to altered metal metabolism, although this was not examined. These data show that glutamate and taurine transport in Mn exposed astrocytes are temporally different

Offset truss hex solar concentrator

A solar energy concentrator system comprises an offset reflector structure made up of a plurality of solar energy reflector panel sections interconnected with one another to form a piecewise approximation of a portion of a (parabolic) surface of revolution rotated about a prescribed focal axis. Each panel section is comprised of a plurality of reflector facets whose reflective surfaces effectively focus reflected light to preselected surface portions of the interior sidewall of a cylindrically shaped solar energy receiver. The longitudinal axis of the receiver is tilted at an acute angle with respect to the optical axis such that the distribution of focussed solar energy over the interior surface of the solar engine is optimized for dynamic solar energy conversion. Each reflector panel section comprises a flat, hexagonally shaped truss support framework and a plurality of beam members interconnecting diametrically opposed corners of the hexagonal framework recessed within which a plurality of (spherically) contoured reflector facets is disposed. The depth of the framework and the beam members is greater than the thickness of a reflector facet such that a reflector facet may be tilted (for controlling the effective focus of its reflected light through the receiver aperture) without protruding from the panel section

Smoking behaviours and cessation services among male physicians in China: Evidence from a structural equation model

Objective To investigate smoking prevalence and cessation services provided by male physicians in hospitals in three Chinese cities. Methods Data were collected from a survey of male physicians employed at 33 hospitals in Changsha, Qingdao and Wuxi City (n=720). Exploratory factor analysis was performed to identify latent variables, and confirmatory structural equation modelling analysis was performed to test the relationships between predictor variables and smoking in male physicians, and their provision of cessation services. Results Of the sampled male physicians, 25.7% were current smokers, and 54.0% provided cessation services by counselling (18.8%), distributing self-help materials (17.1%), and providing traditional remedies or medication (18.2%). Factors that predicted smoking included peer smoking (OR 1.14 95% CI 1.03 to 1.26) and uncommon knowledge (OR 0.94 95% CI 0.89 to 0.99), a variable measuring awareness of the association of smoking with stroke, heart attack, premature ageing and impotence in male adults as well as the role of passive smoking in heart attack. Factors that predicted whether physicians provided smoking cessation services included peer smoking (OR 0.82 95% CI 0.76 to 0.89), physicians’ own smoking (OR 0.87 95% CI 0.81 to 0.93), training in cessation (OR 1.36 95% CI 1.27 to 1.45) and access to smoking cessation resources (OR 1.69 95% CI 1.58 to 1.82). Conclusions The smoke-free policy is not strictly implemented at healthcare facilities, and smoking remains a public health problem among male physicians. A holistic approach, including a stricter implementation of the smoke-free policy, comprehensive education on the hazards of smoking, training in standard smoking-cessation techniques and provision of cessation resources, is needed to curb the smoking epidemic among male physicians and to promote smoking cessation services in China

COMPARISON OF SUPPORT VECTOR REGRESSION AND RANDOM FOREST REGRESSION ALGORITHMS ON GOLD PRICE PREDICTIONS

This research was conducted to test how the Support Vector Regression and Random Forest Regression algorithms predict gold futures prices. The data used in this research was taken from the Investing.com website which will later be processed into a prediction model by comparing the SVR and RVR algorithms. The Support Vector Regression and Random Forest Regression algorithms will be tested to see the performance of each prediction model. The test results show that the Support Vector Regression model is superior in terms of accuracy with a value of 83%. However, the Random Forest Regression algorithm is superior with a smaller error rate, namely with an MSE value of 270.85 and an MAE value of 12.53. Keyword: Comparison, Prediction, Support Vector Regression, Random Forest Regression

Effect of pressure vents on the fast cookoff of energetic materials.

The effect of vents on the fast cookoff of energetic materials is studied through experimental modifications to the confinement vessel of the Radiant Heat Fast Cookoff Apparatus. Two venting schemes were investigated: 1) machined grooves at the EM-cover plate interface; 2) radial distribution of holes in PEEK confiner. EM materials of PBXN-109 and PBX 9502 were tested. Challenges with the experimental apparatus and EM materials were identified such that studying the effect of vents as an independent parameter was not realized. The experimental methods, data and post-test observations are presented and discussed

Smoking susceptibility and its predictors among adolescents in China: Evidence from Ningbo City

Susceptibility to smoking is a risk factor of actual adolescent smoking behaviors. This study aimed to estimate the rate of smoking susceptibility and its predictors in China with a sample of 4,695 junior high school students in Ningbo, China. Core questions from the Global Youth Tobacco Survey (GYTS) were adapted to the China context and administered to these students. The rate of smoking susceptibility, measured by “Do you foresee yourself taking up smoking in the next 12 months”, is 6.1%. Results from logistic regression suggested that among boys, adolescents’ health knowledge that smoking can cause lung cancer (OR=2.73), the belief that smoking can help people relax (OR=2.32), and self-report of never having seen anti-smoking information on campus (OR=1.80) predicted increased susceptibility to smoking. Conversely, the belief that boys who smoke are less attractive (OR=0.64), that parents will have a problem with their child smoking (OR=0.50), having no friends or classmates who smoke (OR=0.22), and not seeing teachers smoke in the previous week (OR=0.61) predicted decreased susceptibility to smoking. Findings for girls were similar. This study suggested the need for comprehensive programs aiming to improve family, peer, and school environments to decrease smoking susceptibility among adolescents

‘It’s like equality now; it’s not as if it’s the old days’: an investigation into gender identity development and football participation of adolescent girls

This article explores the influence participating in football has on the development of adolescent girls’ gender identity, an area which currently lacks academic attention. Data were taken from an ethnographic study with a group of adolescent girls and boys and compared to Jeanes’ research. A social constructionist framework was deployed with links to both critical theory and feminist literature. Qualitative and participatory methods were used to fully engage with the complex issue of gender identity. The girls within this study were aware of the normative gender expectations linked to ‘being a female’ but did not find this restrictive. The girls moved between many changing identities and organised their ‘web of selves’ accordingly. The apparent need to measure success by the parameters of male standards created a barrier to girls’ identity development

Targeting LIF-mediated paracrine interaction for pancreatic cancer therapy and monitoring.

Pancreatic ductal adenocarcinoma (PDAC) has a dismal prognosis largely owing to inefficient diagnosis and tenacious drug resistance. Activation of pancreatic stellate cells (PSCs) and consequent development of dense stroma are prominent features accounting for this aggressive biology1,2. The reciprocal interplay between PSCs and pancreatic cancer cells (PCCs) not only enhances tumour progression and metastasis but also sustains their own activation, facilitating a vicious cycle to exacerbate tumorigenesis and drug resistance3-7. Furthermore, PSC activation occurs very early during PDAC tumorigenesis8-10, and activated PSCs comprise a substantial fraction of the tumour mass, providing a rich source of readily detectable factors. Therefore, we hypothesized that the communication between PSCs and PCCs could be an exploitable target to develop effective strategies for PDAC therapy and diagnosis. Here, starting with a systematic proteomic investigation of secreted disease mediators and underlying molecular mechanisms, we reveal that leukaemia inhibitory factor (LIF) is a key paracrine factor from activated PSCs acting on cancer cells. Both pharmacologic LIF blockade and genetic Lifr deletion markedly slow tumour progression and augment the efficacy of chemotherapy to prolong survival of PDAC mouse models, mainly by modulating cancer cell differentiation and epithelial-mesenchymal transition status. Moreover, in both mouse models and human PDAC, aberrant production of LIF in the pancreas is restricted to pathological conditions and correlates with PDAC pathogenesis, and changes in the levels of circulating LIF correlate well with tumour response to therapy. Collectively, these findings reveal a function of LIF in PDAC tumorigenesis, and suggest its translational potential as an attractive therapeutic target and circulating marker. Our studies underscore how a better understanding of cell-cell communication within the tumour microenvironment can suggest novel strategies for cancer therapy

Depleted uranium is not toxic to rat brain endothelial (RBE4) cells

Abstract: Studies on Gulf War veterans with depleted uranium (DU) fragments embedded in their soft tissues have led to suggestions of possible DU-induced neurotoxicity. We investigated DU uptake into cultured rat brain endothelial cells (RBE4). Following the determination that DU readily enters RBE4 cells, cytotoxic effects were analyzed using assays for cell volume increase, heat shock protein 90 (Hsp90) expression, 3-[4,5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide (MTT) reduction, and lactate dehydrogenase (LDH) activity. The results of these studies show that uptake of the U 3 O 8 uranyl chloride form of DU into RBE4 cells is efficient, but there are little or no resulting cytotoxic effects on these cells as detected by common biomarkers. Thus, the present experimental paradigm is rather reassuring and provides no indication for overt cytotoxicity in endothelial cells exposed to DU. Index Entries: Depleted uranium (DU); heavey metal toxicity; blood-brain barrier; endothelium. Article: INTRODUCTION Depleted uranium (DU) is a component of military munitions and is therefore the subject of important toxicity studies. Specifically, the possibility of DU neurotoxicity is under investigation. DU is a dense heavy metal used without reserve in many military applications. Chemically similar to natural uranium, but depleted of much of the radioactivity of the 235 U and 234 U isotopes, DU is a low-specific-activity metal that has several advantages for use as weapons material. Neurotoxicity could potentially arise from the chemical or radioactive properties of DU, and the level of neurotoxicity is as yet undetermined (1-3). Gulf War veterans with DU fragments embedded in their soft tissues were studied and the results suggested that there might be DU-associated effects on behavior and cognition (1-4). Rats embedded with DU fragments accumulated uranium in a range of tissues, with early levels highest in the kidney and a gradual increase in bone accumulation. Brain tissues were found to have far lower levels, with the hippocampus showing high levels among the brain regions following physiologically relevant exposures and cerebellum accumulating the highest levels upon extremely high exposure levels For a blood-borne contaminant to cause neurotoxicity, it must first cross the blood-brain barrier (BBB). This barrier protects the central nervous system (CNS) from toxicants in the blood, and its ability to protect against metal neurotoxicity was reviewed by Zheng et al. (7). The capillaries of the brain are lined with endothelial cells acting as the first line of defense in the BBB. The high degree of tightness of the junctions that link the endothelial cells virtually prevents any paracellular passage from occurring in physiological conditions. In addition, several transport proteins can increase the brain-to-blood efflux of various compounds (e.g., Pglycoproteins or multidrug resistance proteins [MDR] of the ATP-binding cassette [ABC]) (7). The molecula