577 research outputs found

    Uptake and metabolism of 35S-sulphate by wine yeast

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    The 35S-labelled metabolites obtained by growing three strains of wine yeast in a medium with 35S-sulphate as the sole source of sulphur were methionine, cystine, cystathionine, glutathione and S-adenosylmethionine. Two further compounds were separated and thought to be adducts of sulphite associated non-metabolically with cell wall components.The yeast strains were chosen to represent high sulphide formation, high sulphite formation and a combination of low sulphite and sulphide formation. Comparison of the relative 35S activities of the compounds formed by each strain suggested that sulphide production could be explained in terms of a lowered rate of synthesis of methionine and its activated metabolites leading to lowered control over the production of sulphite reductase. Lowered SAM and methionine production allowing derepression of ATP sulphurylase, together with the reported low activity of sulphite reductase in sulphite producing yeast, could be an explanation for sulphite production.Aufnahme und Umsetzung von 35S-Sulfat durch WeinhefenNach Vergärung eines Substrates mit 35S-Sulfat als einziger Schwefelquelle durch drei Weinhefenstämme - viel H2S, viel SO2 und sowohl wenig H2S als auch SO2 bildend - waren folgende Stoffwechselprodukte radioaktiv markiert: Methionin, Cystin, Cystathionin, Glutathion und S-Adenosylmethionin {SAM). Zwei weitere nicht identifizierte Komponenten kÜnnten Anlagerungsprodukte von Sulfit mit Zellwandkomponenten darstellen.Aus der relativen 35S-Aktivität der Stoffwechselprodukte bei den verschiedenen Hefestämmen kann auf eine verminderte Synthese von Methionin und seinen Metaboliten geschlossen werden. Die mÜglichen Auswirkungen auf die H2S- und SO2- Bildung werden diskutiert

    Search for the disappearance of muon antineutrinos in the NuMI neutrino beam

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    We report constraints on muon antineutrino oscillation parameters that were obtained by using the two MINOS detectors to measure the 7% antineutrino component of the NuMI neutrino beam. In the Far Detector, we select 130 events in the charged-current muon antineutrino sample, compared to a prediction of 136.4 +/- 11.7(stat) ^{+10.2}_{-8.9}(syst) events under the assumption |dm2bar|=2.32x10^-3 eV^2, snthetabar=1.0. A fit to the two-flavor oscillation approximation constrains |dm2bar|<3.37x10^-3 eV^2 at the 90% confidence level with snthetabar=1.0

    Characterizing Hepatitis C Virus–Specific CD4+ T Cells Following Viral‐Vectored Vaccination, Directly Acting Antivirals, and Spontaneous Viral Cure

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    BACKGROUND AND AIMS: Induction of functional helper CD4+ T cells is the hallmark of a protective immune response against hepatitis C virus (HCV), associated with spontaneous viral clearance. Heterologous prime/boost viral vectored vaccination has demonstrated induction of broad and polyfunctional HCV-specific CD8+ T cells in healthy volunteers; however, much less is known about CD4+ T-cell subsets following vaccination. APPROACH AND RESULTS: We analyzed HCV-specific CD4+ T-cell populations using major histocompatibility complex class II tetramers in volunteers undergoing HCV vaccination with recombinant HCV adenoviral/modified vaccinia Ankara viral vectors. Peptide-specific T-cell responses were tracked over time, and functional (proliferation and cytokine secretion) and phenotypic (cell surface and intranuclear) markers were assessed using flow cytometry. These were compared to CD4+ responses in 10 human leukocyte antigen-matched persons with HCV spontaneous resolution and 21 chronically infected patients treated with directly acting antiviral (DAA) therapy. Vaccination induced tetramer-positive CD4+ T cells that were highest 1-4 weeks after boosting (mean, 0.06%). Similar frequencies were obtained for those tracked following spontaneous resolution of disease (mean, 0.04%). In addition, the cell-surface phenotype (CD28, CD127) memory subset markers and intranuclear transcription factors, as well as functional capacity of peptide-specific CD4+ T-cell responses characterized after vaccination, are comparable to those following spontaneous viral resolution. In contrast, helper responses in chronic infection were infrequently detected and poorly functional and did not consistently recover following HCV cure. CONCLUSIONS: Helper CD4+ T-cell phenotype and function following HCV viral vectored vaccination resembles "protective memory" that is observed following spontaneous clearance of HCV. DAA cure does not promote resurrection of exhausted CD4+ T-cell memory in chronic infection

    Rainbow domination and related problems on some classes of perfect graphs

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    Let k∈Nk \in \mathbb{N} and let GG be a graph. A function f:V(G)→2[k]f: V(G) \rightarrow 2^{[k]} is a rainbow function if, for every vertex xx with f(x)=∅f(x)=\emptyset, f(N(x))=[k]f(N(x)) =[k]. The rainbow domination number γkr(G)\gamma_{kr}(G) is the minimum of ∑x∈V(G)∣f(x)∣\sum_{x \in V(G)} |f(x)| over all rainbow functions. We investigate the rainbow domination problem for some classes of perfect graphs

    Searches for neutrinoless double beta decay

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    Neutrinoless double beta decay is a lepton number violating process whose observation would also establish that neutrinos are their own anti-particles. There are many experimental efforts with a variety of techniques. Some (EXO, Kamland-Zen, GERDA phase I and CANDLES) started take data in 2011 and EXO has reported the first measurement of the half life for the double beta decay with two neutrinos of 136^{136}Xe. The sensitivities of the different proposals are reviewed.Comment: 8 pages, prepared for TAUP 201

    Searches for neutrinoless double beta decay

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    Neutrinoless double beta decay is a lepton number violating process whose observation would also establish that neutrinos are their own anti-particles. There are many experimental efforts with a variety of techniques. Some (EXO, Kamland-Zen, GERDA phase I and CANDLES) started take data in 2011 and EXO has reported the first measurement of the half life for the double beta decay with two neutrinos of 136^{136}Xe. The sensitivities of the different proposals are reviewed.Comment: 8 pages, prepared for TAUP 201

    Searches for neutrinoless double beta decay

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    Neutrinoless double beta decay is a lepton number violating process whose observation would also establish that neutrinos are their own anti-particles. There are many experimental efforts with a variety of techniques. Some (EXO, Kamland-Zen, GERDA phase I and CANDLES) started take data in 2011 and EXO has reported the first measurement of the half life for the double beta decay with two neutrinos of 136^{136}Xe. The sensitivities of the different proposals are reviewed.Comment: 8 pages, prepared for TAUP 201

    Paediatric patient safety and the need for aviation black box thinking to learn from and prevent medication errors

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    Since the publication of To Err Is Human: Building a Safer Health System in 1999, there has been much research conducted into the epidemiology, nature and causes of medication errors in children, from prescribing and supply to administration. It is reassuring to see growing evidence of improving medication safety in children; however, based on media reports, it can be seen that serious and fatal medication errors still occur. This critical opinion article examines the problem of medication errors in children and provides recommendations for research, training of healthcare professionals and a culture shift towards dealing with medication errors. There are three factors that we need to consider to unravel what is missing and why fatal medication errors still occur. (1) Who is involved and affected by the medication error? (2) What factors hinder staff and organisations from learning from mistakes? Does the fear of litigation and criminal charges deter healthcare professionals from voluntarily reporting medication errors? (3) What are the educational needs required to prevent medication errors? It is important to educate future healthcare professionals about medication errors and human factors to prevent these from happening. Further research is required to apply aviation’s ‘black box’ principles in healthcare to record and learn from near misses and errors to prevent future events. There is an urgent need for the black box investigations to be published and made public for the benefit of other organisations that may have similar potential risks for adverse events. International sharing of investigations and learning is also needed
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