467 research outputs found

    Characterization of bulk MgB2 synthesized by infiltration and growth

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    Superconducting MgB2 has been synthesized successfully by a modified infiltration and growth (IG) technique. The ambient pressure technique is relatively simple and scalable to complex shaped bulks. The extent of MgB 2 phase formation has been found to be influenced strongly by the IG process time and/or temperature, and this is found to reflect in the X-ray diffraction patterns, magnetization measurements, and microhardness. Scanning electron microscopy images show a bimodal particle size distribution with 20-50 nm sized fine precipitates in the inter particle region. A critical current density of 400 kA cm-2 was measured at 5 K.KACST-Cambridge Research Centre, Cambridge, U.K

    Fetal gender determination through Y-STR analysis of maternal plasma during the third trimester of pregnancy

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    Background: The passage of nucleated cells between mother and fetus is well recognized (Lo et al., 1989, 1996). As well as, cell-free fetal DNA in maternal plasma or serum is at present widely investigated as a source of fetal genetic material (Stanghellini et al., 2006) [18]. There has been much recent interest in the use of DNA derived from plasma or serum (Boland, 1996). This DNA can be utilized for molecular diagnosis as well as prenatal sex discernment.Objective: To establish an easy, reliable, and completely safe method for fetal gender determination alternative to conventional exhausting current techniques applied in gynecologic hospitals and clinics, besides its further applications in forensic casework.Methods: EDTA-Blood samples were taken from 30 pregnant women all in the third trimester of pregnancy, then plasma was separated from each sample, from which DNA was isolated using a QIAamp DNA Mini Kit, with special modifications done in the extracting procedure to concentrate and obtain minute quantities of fetal DNA, together with maternal DNA, from maternal plasma. In addition, bloodstain samples were taken from the husbands of women who were pregnant with male fetuses from which DNA was isolated using a QIAamp DNA Micro Kit for comparison. DNA quantification was done using a Real-time PCR utilizing Quantifiler Duo Kit. PCR was done using an AmpFlSTR Y-Filer Kit, then amplified products were typed using a 3130 Genetic Analyzer.Results: Full and partial Y-STR profiles (6–17 STR loci) were obtained from all plasma samples taken from pregnant women with male fetuses, while negative Y-STR profiles (no single STR locus) were obtained from all plasma samples taken from pregnant women with female fetuses.Conclusion: It is recommended to use Y-STR profiling as an alternative technique for fetal gender determination during the third trimester of pregnancy, in addition to its significance in forensic casework.Keywords: Fetal gender; Maternal plasma; Y-STR analysis; Pregnancy; Forensic casewor

    High Trapped Fields in C-doped MgB2 Bulk Superconductors Fabricated by Infiltration and Growth Process.

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    The grain boundaries in superconducting MgB2 are known to form effective magnetic flux pinning sites and, consequently, bulk MgB2 containing a fine-grain microstructure fabricated from nanoscale Mg and B precursor powders exhibits good magnetic field-trapping performance below 20 K. We report here that the trapped field of MgB2 bulk superconductors fabricated by an infiltration and growth process to yield a dense, pore-free microstructure, can be enhanced significantly by carbon-doping, which increases intra-band scattering within the superconducting grains. A maximum trapped field of 4.15 T has been measured at 7.5 K at the centre of a five-sample stack of Mg(B1-xiCxi)2 bulk superconductors processed by infiltration and growth, which not only represents a ~40% increase in trapped field observed compared to undoped bulk MgB2, but also is the highest trapped field reported to date in MgB2 samples processed under ambient pressure. The trapped field is observed to decay at a rate of <2%/day at 10 K, which suggests that bulk MgB2 superconductors fabricated using the infiltration and growth technique can be used potentially to generate stable, high magnetic fields for a variety of engineering applications

    Increasing Compliance with Mass Drug Administration Programs for Lymphatic Filariasis in India through Education and Lymphedema Management Programs

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    Global elimination of lymphatic filariasis requires giving drugs at least annually to populations who live at risk of becoming infected with the parasite. At least 80% of people at risk need to take the drugs annually for 5 or more years to stop transmission of the infection. People suffering from the long-term effects of infection, such as swollen legs, benefit from programs that teach self-care of their affected limbs. In this study, we assessed the impact of an educational campaign that, after addressing previously identified predictors of compliance, significantly improved drug compliance. The specific factors improving compliance included knowing about the drug distribution in advance, knowing that everyone is at risk for acquiring the infection, knowing that the drug distribution was for lymphatic filariasis prevention, and knowing at least one component of leg care. We also found that areas with programs to assist people with swollen legs had greater increases in compliance. This research provides evidence that program evaluation can be used to improve drug compliance. In addition, our work shows for the first time that programs to benefit people with swollen legs caused by lymphatic filariasis also increase the participation of people without disease in drug treatment programs

    Whole-Body Hypothermia, Cerebral Magnetic Resonance Biomarkers, and Outcomes in Neonates With Moderate or Severe Hypoxic-Ischemic Encephalopathy Born at Tertiary Care Centers vs Other Facilities: A Nested Study Within a Randomized Clinical Trial

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    IMPORTANCE: The association between place of birth and hypothermic neuroprotection after hypoxic-ischemic encephalopathy (HIE) in low- and middle-income countries (LMICs) is unknown. OBJECTIVE: To ascertain the association between place of birth and the efficacy of whole-body hypothermia for protection against brain injury measured by magnetic resonance (MR) biomarkers among neonates born at a tertiary care center (inborn) or other facilities (outborn). Design, Setting, and PARTICIPANTS: This nested cohort study within a randomized clinical trial involved neonates at 7 tertiary neonatal intensive care units in India, Sri Lanka, and Bangladesh between August 15, 2015, and February 15, 2019. A total of 408 neonates born at or after 36 weeks' gestation with moderate or severe HIE were randomized to receive whole-body hypothermia (reduction of rectal temperatures to between 33.0 °C and 34.0 °C; hypothermia group) for 72 hours or no whole-body hypothermia (rectal temperatures maintained between 36.0 °C and 37.0 °C; control group) within 6 hours of birth, with follow-up until September 27, 2020. Exposure: 3T MR imaging, MR spectroscopy, and diffusion tensor imaging. MAIN OUTCOMES AND MEASURES: Thalamic N-acetyl aspartate (NAA) mmol/kg wet weight, thalamic lactate to NAA peak area ratios, brain injury scores, and white matter fractional anisotropy at 1 to 2 weeks and death or moderate or severe disability at 18 to 22 months. RESULTS: Among 408 neonates, the mean (SD) gestational age was 38.7 (1.3) weeks; 267 (65.4%) were male. A total of 123 neonates were inborn and 285 were outborn. Inborn neonates were smaller (mean [SD], 2.8 [0.5] kg vs 2.9 [0.4] kg; P = .02), more likely to have instrumental or cesarean deliveries (43.1% vs 24.7%; P = .01), and more likely to be intubated at birth (78.9% vs 29.1%; P = .001) than outborn neonates, although the rate of severe HIE was not different (23.6% vs 17.9%; P = .22). Magnetic resonance data from 267 neonates (80 inborn and 187 outborn) were analyzed. In the hypothermia vs control groups, the mean (SD) thalamic NAA levels were 8.04 (1.98) vs 8.31 (1.13) among inborn neonates (odds ratio [OR], -0.28; 95% CI, -1.62 to 1.07; P = .68) and 8.03 (1.89) vs 7.99 (1.72) among outborn neonates (OR, 0.05; 95% CI, -0.62 to 0.71; P = .89); the median (IQR) thalamic lactate to NAA peak area ratios were 0.13 (0.10-0.20) vs 0.12 (0.09-0.18) among inborn neonates (OR, 1.02; 95% CI, 0.96-1.08; P = .59) and 0.14 (0.11-0.20) vs 0.14 (0.10-0.17) among outborn neonates (OR, 1.03; 95% CI, 0.98-1.09; P = .18). There was no difference in brain injury scores or white matter fractional anisotropy between the hypothermia and control groups among inborn or outborn neonates. Whole-body hypothermia was not associated with reductions in death or disability, either among 123 inborn neonates (hypothermia vs control group: 34 neonates [58.6%] vs 34 [56.7%]; risk ratio, 1.03; 95% CI, 0.76-1.41), or 285 outborn neonates (hypothermia vs control group: 64 neonates [46.7%] vs 60 [43.2%]; risk ratio, 1.08; 95% CI, 0.83-1.41). CONCLUSIONS AND RELEVANCE: In this nested cohort study, whole-body hypothermia was not associated with reductions in brain injury after HIE among neonates in South Asia, irrespective of place of birth. These findings do not support the use of whole-body hypothermia for HIE among neonates in LMICs. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02387385

    Supersymmetric contributions to Bˉsϕπ0\bar{B}_s \to \phi \pi^0 and Bˉsϕρ0\bar{B}_s \to \phi \rho^0 decays in SCET

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    We study the decay modes Bˉsϕπ0\bar{B}_s\to \phi \pi^0 and Bˉsϕρ0\bar{B}_s\to \phi \rho^0 using Soft Collinear Effective Theory. Within Standard Model and including the error due to the SU(3) breaking effect in the SCET parameters we find that BR Bˉsϕπ0=712+1+2×108\bar{B}_s\to \phi \pi^0 =7_{-1-2}^{+1+2}\times 10^{-8} and BR Bˉsϕπ0=914+1+3×108\bar{B}_s\to \phi \pi^0=9_{-1-4}^{+1+3}\times 10^{-8} corresponding to solution 1 and solution 2 of the SCET parameters respectively.For the decay mode Bˉsϕρ0\bar{B}_s\to \phi \rho^0, we find that BR Bˉsϕρ0=20.2112+1+9×108\bar{B}_s\to \phi \rho^0 = 20.2^{+1+9}_{-1-12}\times 10^{-8} and BR Bˉsϕρ0=34.01.522+1.5+15×108 \bar{B}_s\to \phi \rho^0 = 34.0^{+1.5 + 15}_{-1.5-22}\times 10^{-8} corresponding to solution 1 and solution 2 of the SCET parameters respectively. We extend our study to include supersymmetric models with non-universal A-terms where the dominant contributions arise from diagrams mediated by gluino and chargino exchanges. We show that gluino contributions can not lead to an enhancement of the branching ratios of Bˉsϕπ0\bar{B}_s\to \phi \pi^0 and Bˉsϕρ0\bar{B}_s\to \phi \rho^0. In addition, we show that SUSY contributions mediated by chargino exchange can enhance the branching ratio of Bˉsϕπ0\bar{B}_s\to \phi \pi^0 by about 14% with respect to the SM prediction. For the branching ratio of Bˉsϕρ0\bar{B}_s\to \phi \rho^0, we find that SUSY contributions can enhance its value by about 1% with respect to the SM prediction.Comment: 25 pages,5 figures, version accepted for publicatio

    Factors Associated with the Performance of a Blood-Based Interferon-γ Release Assay in Diagnosing Tuberculosis

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    Background: Indeterminate results are a recognised limitation of interferon-γ release assays (IGRA) in the diagnosis of latent tuberculosis (TB) infection (LTBI) and TB disease, especially in children. We investigated whether age and common co-morbidities were associated with IGRA performance in an unselected cohort of resettled refugees. Methods: A retrospective cross-sectional study of refugees presenting for their post-resettlement health assessment during 2006 and 2007. Refugees were investigated for prevalent infectious diseases, including TB, and for common nutritional deficiencies and haematological abnormalities as part of standard clinical screening protocols. Tuberculosis screening was performed by IGRA; QuantiFERON-TB Gold in 2006 and QuantiFERON-TBGold In-Tube in 2007. Results: Complete data were available on 1130 refugees, of whom 573 (51%) were children less than 17 years and 1041 (92%) were from sub-Saharan Africa. All individuals were HIV negative. A definitive IGRA result was obtained in 1004 (89%) refugees, 264 (26%) of which were positive; 256 (97%) had LTBI and 8 (3%) had TB disease. An indeterminate IGRA result was obtained in 126 (11%) refugees (all failed positive mitogen control). In multivariate analysis, younger age (linear OR = 0.93 [95% CI 0.91-0.95],

    Pichia pastoris versus Saccharomyces cerevisiae:a case study on the recombinant production of human granulocyte-macrophage colony-stimulating factor

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    BACKGROUND: Recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) is a glycoprotein that has been approved by the FDA for the treatment of neutropenia and leukemia in combination with chemotherapies. Recombinant hGM-CSF is produced industrially using the baker's yeast, Saccharomyces cerevisiae, by large-scale fermentation. The methylotrophic yeast, Pichia pastoris, has emerged as an alternative host cell system due to its shorter and less immunogenic glycosylation pattern together with higher cell density growth and higher secreted protein yield than S. cerevisiae. In this study, we compared the pipeline from gene to recombinant protein in these two yeasts. RESULTS: Codon optimization in silico for both yeast species showed no difference in frequent codon usage. However, rhGM-CSF expressed from S. cerevisiae BY4742 showed a significant discrepancy in molecular weight from those of P. pastoris X33. Analysis showed purified rhGM-CSF species with molecular weights ranging from 30 to more than 60 kDa. Fed-batch fermentation over 72 h showed that rhGM-CSF was more highly secreted from P. pastoris than S. cerevisiae (285 and 64 mg total secreted protein/L, respectively). Ion exchange chromatography gave higher purity and recovery than hydrophobic interaction chromatography. Purified rhGM-CSF from P. pastoris was 327 times more potent than rhGM-CSF from S. cerevisiae in terms of proliferative stimulating capacity on the hGM-CSF-dependent cell line, TF-1. CONCLUSION: Our data support a view that the methylotrophic yeast P. pastoris is an effective recombinant host for heterologous rhGM-CSF production
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