947 research outputs found
The EMBLA survey - metal-poor stars in the Galactic bulge
Cosmological models predict the oldest stars in the Galaxy should be found closest to the centre of the potential well, in the bulge. The Extremely Metal-poor BuLge stars with AAOmega survey (EMBLA) successfully searched for these old, metal-poor stars by making use of the distinctive SkyMapper photometric filters to discover candidate metal-poor stars in the bulge. Their metal-poor nature was then confirmed using the AAOmega spectrograph on the Anglo-Australian Telescope. Here we present an abundance analysis of 10 bulge stars with −2.8 < [Fe/H] < −1.7 from MIKE/Magellan observations, in total determining the abundances of 22 elements. Combining these results with our previous high-resolution data taken as part of the Gaia-ESO Survey, we have started to put together a picture of the chemical and kinematic nature of the most metal-poor stars in the bulge. The currently available kinematic data are consistent with the stars belonging to the bulge, although more accurate measurements are needed to constrain the stars’ orbits. The chemistry of these bulge stars deviates from that found in halo stars of the same metallicity. Two notable differences are the absence of carbon-enhanced metal-poor bulge stars, and the α element abundances exhibit a large intrinsic scatter and include stars which are underabundant in these typically enhanced elements.LMH and MA have been supported by the Australian Research Council (grant FL110100012). ARC acknowledges support from the European Union FP7 programme through ERC grant number 320360. DY is supported through an Australian Research Council Future Fellowship (FT140100554). Research on metal-poor stars with SkyMapper is supported through Australian Research Council Discovery Projects grants DP120101237 and DP150103294 (PI: Da Costa). This publication makes use of data products from the Two Micron All Sky Survey, which is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center/California Institute of Technology, funded by the National Aeronautics and Space Administration and the National Science Foundation. This paper includes data gathered with the 6.5 metre Magellan Telescopes located at Las Campanas Observatory, Chile.This is the final version of the article. It first appeared from Oxford University Press via http://dx.doi.org/10.1093/mnras/stw100
Effects of external nutrient sources and extreme weather events on the nutrient budget of a Southern European coastal lagoon
The seasonal and annual nitrogen (N), phosphorus (P), and carbon (C) budgets of the mesotidal Ria Formosa lagoon, southern Portugal, were estimated to reveal the main inputs and outputs, the seasonal patterns, and how they may influence the ecological functioning of the system. The effects of extreme weather events such as long-lasting strong winds causing upwelling and strong rainfall were assessed. External nutrient inputs were quantified; ocean exchange was assessed in 24-h sampling campaigns, and final calculations were made using a hydrodynamic model of the lagoon. Rain and stream inputs were the main freshwater sources to the lagoon. However, wastewater treatment plant and groundwater discharges dominated nutrient input, together accounting for 98, 96, and 88 % of total C, N, and P input, respectively. Organic matter and nutrients were continuously exported to the ocean. This pattern was reversed following extreme events, such as strong winds in early summer that caused upwelling and after a period of heavy rainfall in late autumn. A principal component analysis (PCA) revealed that ammonium and organic N and C exchange were positively associated with temperature as opposed to pH and nitrate. These variables reflected mostly the benthic lagoon metabolism, whereas particulate P exchange was correlated to Chl a, indicating that this was more related to phytoplankton dynamics. The increase of stochastic events, as expected in climate change scenarios, may have strong effects on the ecological functioning of coastal lagoons, altering the C and nutrient budgets.Portuguese Science and Technology Foundation (FCT) [POCI/MAR/58427/2004, PPCDT/MAR/58427/2004]; Portuguese Science and Technology Foundation (FCT
Potential health impacts of heavy metals on HIV-infected population in USA.
Noninfectious comorbidities such as cardiovascular diseases have become increasingly prevalent and occur earlier in life in persons with HIV infection. Despite the emerging body of literature linking environmental exposures to chronic disease outcomes in the general population, the impacts of environmental exposures have received little attention in HIV-infected population. The aim of this study is to investigate whether individuals living with HIV have elevated prevalence of heavy metals compared to non-HIV infected individuals in United States. We used the National Health and Nutrition Examination Survey (NHANES) 2003-2010 to compare exposures to heavy metals including cadmium, lead, and total mercury in HIV infected and non-HIV infected subjects. In this cross-sectional study, we found that HIV-infected individuals had higher concentrations of all heavy metals than the non-HIV infected group. In a multivariate linear regression model, HIV status was significantly associated with increased blood cadmium (p=0.03) after adjusting for age, sex, race, education, poverty income ratio, and smoking. However, HIV status was not statistically associated with lead or mercury levels after adjusting for the same covariates. Our findings suggest that HIV-infected patients might be significantly more exposed to cadmium compared to non-HIV infected individuals which could contribute to higher prevalence of chronic diseases among HIV-infected subjects. Further research is warranted to identify sources of exposure and to understand more about specific health outcomes
Chronic administration of Abarema cochliacarpos attenuates colonic inflammation in rats
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Inflammatory bowel diseases are characterized by a chronic clinical course of relapse and remission associated with self-destructive inflammation of the gastrointestinal tract. Active extracts from plants have emerged as natural potential candidates for its treatment. Abarema cochliacarpos (Gomes) Barneby & Grimes, Fabaceae (Barbatimao), is a native medicinal plant in to Brazil. Previously we have demonstrated in an acute colitis model a marked protective effect of a butanolic extract, so we decided to assess its anti-inflammatory effect in a chronic ulcerative colitis model induced by trinitrobenzensulfonic acid (TNBS). Abarema cochliacarpos (150 mg/day, v.o.) was administered for fourteen consecutive days. This treatment decreased significantly macroscopic damage as compared with TNBS. Histological analysis showed that the extract improved the microscopic structure. Myeloperoxidase activity (MPO) was significantly decreased. Study of cytokines showed that TNF-alpha was diminished and IL-10 level was increased after Abarema cochliacarpos treatment. In order to elucidate inflammatory mechanisms, expression of cyclooxygenase (COX)-2 and nitric oxide synthase (iNOS) were studied showing a significant downregulation. In addition, there was reduction in the JNK and p-38 activation. Finally, I kappa B degradation was blocked by Abarema cochliacarpos treatment being consistent with an up-regulation of the NF-kappaB-binding activity. These results reinforce the anti-inflammatory effects described previously suggesting that Abarema cochliacarpos could provide a source for the search for new anti-inflammatory compounds useful in ulcerative colitis treatment.214680690Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Universidade Estadual de Alagoas, BrazilInstituto Federal de Educacao Ciencia e Tecnologia-Sergipe, BrazilCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES
Niobium and niobium-iron coatings on API 5LX 70 steel applied with HVOF
The present study aimed to create and characterize niobium and niobium-iron60% coatings applied to steel API 5L X70 using the hypersonic thermal spray process (HVOF). The morphologies of the coatings were analyzed using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and profilometry, while the coatings’ hardnesses was evaluated using the Vickers hardness test. The coatings’ corrosion resistance was evaluated by monitoring their open circuit potential and potentiodynamic polarization and performing electrochemical impedance spectroscopy in a 0.05 M NaCl solution. The results showed that the niobium-iron coating contained minor porosity regions, while such defects occurred over large regions of the niobium coating. In terms of corrosion resistance, the coatings obtained in this work promoted a reduction in the substrate’s corrosion rate, but the presence of discontinuities such as porosity compromised the barrier effects of these coatings
Healthcare-associated pneumonia among hospitalized patients in a Korean tertiary hospital
<p>Abstract</p> <p>Background</p> <p>Healthcare-associated pneumonia (HCAP) has more similarities to nosocomial pneumonia than to community-acquired pneumonia (CAP). However, there have only been a few epidemiological studies of HCAP in South Korea. We aimed to determine the differences between HCAP and CAP in terms of clinical features, pathogens, and outcomes, and to clarify approaches for initial antibiotic management.</p> <p>Methods</p> <p>We conducted a retrospective, observational study of 527 patients with HCAP or CAP who were hospitalized at Severance Hospital in South Korea between January and December 2008.</p> <p>Results</p> <p>Of these patients, 231 (43.8%) had HCAP, and 296 (56.2%) had CAP. Potentially drug-resistant (PDR) bacteria were more frequently isolated in HCAP than CAP (12.6% vs. 4.7%; <it>P </it>= 0.001), especially in the low-risk group of the PSI classes (41.2% vs. 13.9%; <it>P </it>= 0.027). In-hospital mortality was higher for HCAP than CAP patients (28.1% vs. 10.8%, <it>P </it>< 0.001), especially in the low-risk group of PSI classes (16.4% vs. 3.1%; <it>P </it>= 0.001). Moreover, tube feeding and prior hospitalization with antibiotic treatment within 90 days of pneumonia onset were significant risk factors for PDR pathogens, with odds ratios of 14.94 (95% CI 4.62-48.31; <it>P </it>< 0.001) and 2.68 (95% CI 1.32-5.46; <it>P </it>= 0.007), respectively.</p> <p>Conclusions</p> <p>For HCAP patients with different backgrounds, various pathogens and antibiotic resistance of should be considered, and careful selection of patients requiring broad-spectrum antibiotics is important when physicians start initial antibiotic treatments.</p
Potential role and chronology of abnormal expression of the Deleted in Colon Cancer (DCC) and the p53 proteins in the development of gastric cancer
BACKGROUND: Loss of activity of tumor suppressor genes is considered a fundamental step in a genetic model of carcinogenesis. Altered expression of the p53 and the Deleted in Colon Cancer (DCC) proteins has been described in gastric cancer and this event may have a role in the development of the disease. According to this hypothesis, we investigated the p53 and the DCC proteins expression in different stages of gastric carcinomas. METHODS: An immunohistochemical analysis for detection of p53 and DCC proteins expression was performed in tumor tissue samples of patients with UICC stage I and II gastric cancer. For the purpose of the analysis, the staining results were related to the pathologic data and compared between stage categories. RESULTS: Ninety-four cases of gastric cancer were analyzed. Disease stage categories were pT1N0 in 23 cases, pT2N0 in 20 cases, pT3N0 in 20 cases and pT1-3 with nodal involvment in 31 cases. Stage pT1-2N0 tumors maintained a positive DCC expression while it was abolished in pT3N0 tumors (p <.001). A significant higher proportion of patients with N2 nodal involvement showed DCC negative tumors. In muscular-invading tumors (pT2-3N0) the majority of cases showed p53 overexpression, whereas a significantly higher proportion of cases confined into the mucosa (pT1N0) showed p53 negative tumors. Also, a higher frequency of p53 overexpression was detected in cases with N1 and N2 metastatic lymphnodal involvement. CONCLUSIONS: Altered expression of both DCC and p53 proteins is detectable in gastric carcinomas. It seems that loss of wild-type p53 gene function and consequent p53 overexpression may be involved in early stages of tumor progression while DCC abnormalities are a late event
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