5,834 research outputs found

    Scalar f0 and a0 mesons in radiative ϕ→K+K−γ decay

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    AbstractWe study the radiative ϕ→K+K−γ decay within a phenomenological framework by considering the contributions of the f0(980) and a0(980) scalar resonances. We consider the kaon-loop model and the no-structure model to evaluate these contributions and compare the results obtained in two models

    Germ line BRCA1 and BRCA2 gene mutations in Turkish breast cancer patients

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    Cataloged from PDF version of article.Germ line BRCA1 and/or BRCA2 mutations were screened in 50 Turkish breast and/or ovarian cancer patients composed of hereditary, familial, early onset and male cancer groups. Genomic DNA samples were tested by heteroduplex analysis and DNA sequencing. Two truncating BRCA2 mutations, one novel (6880 insG) and one previously reported (3034 delAAAC), were found in two out of six (33%) hereditary breast and/or ovarian cancer patients. A novel truncating (1200 insA) and a missense (2080A→G) BRCA1 mutation was found in two of 27 (7%) individuals in the early onset group. A total of four (8%) disease-causing mutations in 50 breast cancer patients were identified in BRCA1 and BRCA2 genes. In addition, five BRCA1 sequence variants have been identified in 23 patients. These results indicate that BRCA1 and BRCA2 genes are involved in some, but not all, forms of hereditary predisposition to breast cancer in the Turkish population. Copyright (C) 2000

    Tribological Behavior of Near-Frictionless Carbon Coatings in High- and Low- Sulfur Diesel Fuels

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    The sulfur content in diesel fuel has a significant effect on diesel engine emissions, which are currently subject to environmental regulations. It has been observed that engine particulate and gaseous emissions are directly proportional to fuel sulfur content. With the introduction of low-sulfur fuels, significant reductions in emissions are expected. The process of sulfur reduction in petroleum-based diesel fuels also reduces the lubricity of the fuel, resulting in premature failure of fuel injectors. Thus, another means of preventing injector failures is needed for engines operating with low-sulfur diesel fuels. In this study, the authors evaluated a near-frictionless carbon (NFC) coating (developed at Argonne National Laboratory) as a possible solution to the problems associated with fuel injector failures in low-lubricity fuels. Tribological tests were conducted with NFC-coated and uncoated H13 and 52100 steels lubricated with high- and low- sulfur diesel fuels in a high-frequency reciprocating test machine. The test results showed that the NFC coatings reduced wear rates by a factor of 10 over those of uncoated steel surfaces. In low-sulfur diesel fuel, the reduction in wear rate was even greater (i.e., by a factor of 12 compared to that of uncoated test pairs), indicating that the NFC coating holds promise as a potential solution to wear problems associated with the use of low-lubricity diesel fuels

    Analysis of design parameters in SIL-4 safety-critical computer

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    Nowadays, Safety-critical computers are extensively used in may civil domains like transportation including railways, avionics and automotive. We noticed that in design of some previous works, some critical safety design parameters like failure diagnostic coverage (DC) or common cause failure (CCF) ratio have not been seriously taken into account. Moreover, in some cases safety has not been compared with standard safety levels (IEC-61508 SIL1-SIL4) or even have not met them. Most often, it is not very clear that which part of the system is the Achilles' heel and how design can be improved to reach standard safety levels. Motivated by such design ambiguities, we aim to study the effect of various design parameters on safety in some prevalent safety configurations: 1oo2 and 2oo3. 1oo1 is also used as a reference. By employing Markov modeling, sensitivity of safety to each of the following critical design parameters is analyzed: failure rate of processing element, failure diagnostics coverage, common cause failures and repair rates. This study gives a deeper sense regarding influence of variation in design parameters over safety. Consequently, to meet appropriate safety integrity level, instead of improving some system parts blindly, it will be possible to make an informed decision on more relevant parameters. © 2017 IEEE

    Influence of intensive melt shearing on the microstructure and mechanical properties of an Al-Mg alloy with high added impurity content

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    The official published version can be accessed from the link below - Copyright @ The Minerals, Metals & Materials Society and ASM International 2011We have investigated the influence of melt conditioning by intensive shearing on the mechanical behavior and microstructure of Al-Mg-Mn-Fe-Cu-Si alloy sheet produced from a small book mold ingot with high added impurity content. The melt conditioned ingot has fine grains throughout its cross section, whereas a conventionally cast ingot, without melt shearing, has coarser grains and shows a wider variation of grain size. Both needle-shaped and coarse Chinese script iron bearing intermetallic particles are found in the microstructure at the center of the conventionally processed ingot, but for the melt conditioned ingot, only fine Chinese script intermetallic particles are observed. In addition to the iron bearing intermetallics, Mg2Si particles are also observed. The ingots were rolled to thin sheet and solution heat treated (SHT). During rolling, the iron-based intermetallics and Mg2Si particles are broken and aligned along the rolling direction. Yield strength (YS), ultimate tensile strength (UTS), and elongation of the intensively melt sheared and processed sheet are all improved compared to the conventionally cast and processed sheet. Fractographic analysis of the tensile fracture surfaces shows that the clustered and coarse iron bearing intermetallic particles are responsible for the observed reduction in mechanical properties of the conventionally cast sheet. We have shown that by refining the initial microstructure of the ingot by intensive shear melt conditioning, it is possible to achieve improved mechanical properties at the final sheet gage of an AlMgMn alloy with a high content of impurities.This study is under the Technology Strategy Board funded REALCAR projec

    Involvement of patients or their representatives in quality management functions in EU hospitals:implementation and impact on patient-centred care strategies

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    OBJECTIVE: The objective of this study was to describe the involvement of patients or their representatives in quality management (QM) functions and to assess associations between levels of involvement and the implementation of patient-centred care strategies. DESIGN: A cross-sectional, multilevel STUDY DESIGN: that surveyed quality managers and department heads and data from an organizational audit. SETTING: Randomly selected hospitals (n = 74) from seven European countries (The Czech Republic, France, Germany, Poland, Portugal, Spain and Turkey). PARTICIPANTS: Hospital quality managers (n = 74) and heads of clinical departments (n = 262) in charge of four patient pathways (acute myocardial infarction, stroke, hip fracture and deliveries) participated in the data collection between May 2011 and February 2012. MAIN OUTCOME MEASURES: Four items reflecting essential patient-centred care strategies based on an on-site hospital visit: (1) formal survey seeking views of patients and carers, (2) written policies on patients' rights, (3) patient information literature including guidelines and (4) fact sheets for post-discharge care. The main predictors were patient involvement in QM at the (i) hospital level and (ii) pathway level. RESULTS: Current levels of involving patients and their representatives in QM functions in European hospitals are low at hospital level (mean score 1.6 on a scale of 0 to 5, SD 0.7), but even lower at departmental level (mean 0.6, SD 0.7). We did not detect associations between levels of involving patients and their representatives in QM functions and the implementation of patient-centred care strategies; however, the smallest hospitals were more likely to have implemented patient-centred care strategies. CONCLUSIONS: There is insufficient evidence that involving patients and their representatives in QM leads to establishing or implementing strategies and procedures that facilitate patient-centred care; however, lack of evidence should not be interpreted as evidence of no effect

    Potential health impacts of heavy metals on HIV-infected population in USA.

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    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

    MIR376A is a regulator of starvation-induced autophagy

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    Background: Autophagy is a vesicular trafficking process responsible for the degradation of long-lived, misfolded or abnormal proteins, as well as damaged or surplus organelles. Abnormalities of the autophagic activity may result in the accumulation of protein aggregates, organelle dysfunction, and autophagy disorders were associated with various diseases. Hence, mechanisms of autophagy regulation are under exploration. Methods: Over-expression of hsa-miR-376a1 (shortly MIR376A) was performed to evaluate its effects on autophagy. Autophagy-related targets of the miRNA were predicted using Microcosm Targets and MIRanda bioinformatics tools and experimentally validated. Endogenous miRNA was blocked using antagomirs and the effects on target expression and autophagy were analyzed. Luciferase tests were performed to confirm that 3’ UTR sequences in target genes were functional. Differential expression of MIR376A and the related MIR376B was compared using TaqMan quantitative PCR. Results: Here, we demonstrated that, a microRNA (miRNA) from the DlkI/Gtl2 gene cluster, MIR376A, played an important role in autophagy regulation. We showed that, amino acid and serum starvation-induced autophagy was blocked by MIR376A overexpression in MCF-7 and Huh-7 cells. MIR376A shared the same seed sequence and had overlapping targets with MIR376B, and similarly blocked the expression of key autophagy proteins ATG4C and BECN1 (Beclin 1). Indeed, 3’ UTR sequences in the mRNA of these autophagy proteins were responsive to MIR376A in luciferase assays. Antagomir tests showed that, endogenous MIR376A was participating to the control of ATG4C and BECN1 transcript and protein levels. Moreover, blockage of endogenous MIR376A accelerated starvation-induced autophagic activity. Interestingly, MIR376A and MIR376B levels were increased with different kinetics in response to starvation stress and tissue-specific level differences were also observed, pointing out to an overlapping but miRNA-specific biological role. Conclusions: Our findings underline the importance of miRNAs encoded by the DlkI/Gtl2 gene cluster in stress-response control mechanisms, and introduce MIR376A as a new regulator of autophagy
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