93 research outputs found

    Hydronium-dominated ion transport in carbon-dioxide-saturated electrolytes at low salt concentrations in nanochannels

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    Nanochannel ion transport is known to be governed by surface charge at low ionic concentrations. In this paper, we show that this surface charge is typically dominated by hydronium ions arising from dissolution of ambient atmospheric carbon dioxide. Taking the hydronium ions into account, we model the nanochannel conductance at low salt concentrations and identify a conductance minimum before saturation at a value independent of salt concentration in the dilute limit. Via the Poisson-Boltzmann equation, our model self-consistently couples chemical-equilibrium dissociation models of the silica wall and of the electrolyte bulk, parametrized by the dissociation reaction constants. Experimental data with aqueous KCl solutions in 165-nm-high silica nanochannels are described well by our model, both with and without extra hydronium from added HCl

    Breeding unicorns:Developing trustworthy and scalable randomness beacons

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    Randomness beacons are services that periodically emit a random number, allowing users to base decisions on the same random value without trusting anyone: ideally, the randomness beacon does not only produce unpredictable values, but is also of low computational complexity for the users, bias-resistant and publicly verifiable. Such randomness beacons can serve as an important primitive for smart contracts in a variety of contexts. This paper first presents a structured security analysis, based on which we then design, implement, and evaluate a trustworthy and efficient randomness beacon. Our approach does not require users to register or run any computationally intensive operations. We then compare different implementation and deployment options on distributed ledgers, and report on an Ethereum smart contract-based lottery using our beacon

    Biotin starvation causes mitochondrial protein hyperacetylation and partial rescue by the SIRT3-like deacetylase Hst4p

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    The essential vitamin biotin is a covalent and tenaciously attached prosthetic group in several carboxylases that play important roles in the regulation of energy metabolism. Here we describe increased acetyl-CoA levels and mitochondrial hyperacetylation as downstream metabolic effects of biotin deficiency. Upregulated mitochondrial acetylation sites correlate with the cellular deficiency of the Hst4p deacetylase, and a biotin-starvation-induced accumulation of Hst4p in mitochondria supports a role for Hst4p in lowering mitochondrial acetylation. We show that biotin starvation and knockout of Hst4p cause alterations in cellular respiration and an increase in reactive oxygen species (ROS). These results suggest that Hst4p plays a pivotal role in biotin metabolism and cellular energy homeostasis, and supports that Hst4p is a functional yeast homologue of the sirtuin deacetylase SIRT3. With biotin deficiency being involved in various metabolic disorders, this study provides valuable insight into the metabolic effects biotin exerts on eukaryotic cells

    Effectiveness and Safety of Ticagrelor Implementation in Patients with Acute Coronary Syndrome undergoing Percutaneous Coronary Intervention:A Cohort Study in Western Denmark

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    BACKGROUND: Ticagrelor was introduced in Denmark in 2011 after randomised data showed its superiority over clopidogrel for patients with acute coronary syndrome (ACS). We assessed the effectiveness and safety of ticagrelor implementation in ACS patients undergoing percutaneous coronary intervention (PCI). METHODS: We identified PCI-treated ACS patients in Western Denmark who redeemed a P2Y12 inhibitor prescription within 14 days. Using Danish health registries, 1-year outcomes were compared before (2007-2010) and after (2012-2015) introduction of ticagrelor. Outcomes were MACE (death, myocardial infarction, and ischaemic stroke) and hospitalisation for bleeding. Inverse probability of treatment weights were used to estimate weighted incidence rate ratios (wIRRs). FINDINGS: We included 14,450 patients; 7,102 were treated in the earlier time period (99·9% clopidogrel) and 7,348 in the later time period (87·8% ticagrelor). Ticagrelor implementation was not associated with a clinically relevant difference in 1-year risk of MACE with 413 events in the ticagrelor period vs. 424 events in the clopidogrel period (cumulative incidence percentage [CIP] 5·6% vs. 6·0%; wIRR 1·06, 95% CI 0·92-1·22). The 1-year risk of bleeding was also similar between groups with 335 bleedings requiring hospitalisation in the ticagrelor period vs. 309 events in the clopidogrel period (CIP 4·6% vs. 4·4%; wIRR 1·05, 95% CI 0·89-1·23). Results were robust in patients above and below 70 years of age. INTERPRETATION: Implementation of ticagrelor was not associated with changes in risks of ischaemic or bleeding events in Danish PCI-treated ACS patients

    Concomitant use of clopidogrel and statins and risk of major adverse cardiovascular events following coronary stent implantation: The clopidogrel-statin interaction

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    To examine whether CYP3A4-metabolizing statin use modified the association between clopidogrel use and major adverse cardiovascular events (MACE) after coronary stent implantation, using time-varying drug exposure ascertainment

    Monoclonal antibodies targeting the disintegrin-like domain of ADAMDEC1 modulates the proteolytic activity and enables quantification of ADAMDEC1 protein in human plasma

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    Decysin-1 (ADAMDEC1) is an orphan ADAM-like metalloprotease with unknown biological function and a short domain structure. ADAMDEC1 mRNA has previously been demonstrated primarily in macrophages and mature dendritic cells. Here, we generated monoclonal antibodies (mAbs) against the mature ADAMDEC1 protein, as well as mAbs specific for the ADAMDEC1 pro-form, enabling further investigations of the metalloprotease. The generated mAbs bind ADAMDEC1 with varying affinity and represent at least six different epitope bins. Binding of mAbs to one epitope bin in the C-terminal disintegrin-like domain efficiently reduces the proteolytic activity of ADAMDEC1. A unique mAb, also recognizing the disintegrin-like domain, stimulates the caseinolytic activity of ADAMDEC1 while having no significant effect on the proteolysis of carboxymethylated transferrin. Using two different mAbs binding the disintegrin-like domain, we developed a robust, quantitative sandwich ELISA and demonstrate secretion of mature ADAMDEC1 protein by primary human macrophages. Surprisingly, we also found ADAMDEC1 present in human plasma with an approximate concentration of 0.5 nM. The presence of ADAMDEC1 both in human plasma and in macrophage cell culture supernatant were biochemically validated using immunoprecipitation and Western blot analysis demonstrating that ADAMDEC1 is secreted in a mature form
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