1,486 research outputs found
Photoswitchable catalysis by a nanozyme mediated by a lightsensitive cofactor
The activity of a gold nanoparticle-based
catalyst can be reversibly up- and down-regulated by light.
Light is used to switch a small molecule between cis- and
trans-isomers, which inhibits the catalytic activity of the
nanoparticles to different extent. The system is functional
in aqueous buffer, which paves the way for integrating the
system in biological networks
Characterization of highly dispersed Ni/Al2O3 catalysts by EXAFS analysis of higher shells
The size and morphology of Ni/Al2O3 catalysts in the oxidic, reduced, and passivated state were determined by EXAFS analysis of the higher shells around the Ni atoms. In the oxidic state, the Ni cations were present in small NiOx particles with predominant (111) plane. Below 4.5 wt% Ni loading, the NiOx particles consisted of one Ni layer, and of two or three Ni layers above 4.5 wt% Ni. A Ni-Al contribution was observed in samples with low Ni loading. The layer which is in contact with the Al2O3 surface is affected by the support surface and its structure is highly distorted, while the other layers were not distorted and have a structure similar to that in bulk NiO. In the reduced state, the number of Ni metal atoms in the reduced Ni particles was smaller than 100 with a narrow distribution below a loading of 15.6 wt% Ni. Above this loading, the particle size suddenly increased and the distribution became wider. The distances and Debye-Waller factors were similar to those of bulk nickel which suggested a weak interaction between the particles and the support. In the passivated state, Ni kernels with 20-40 metal atoms were covered by a one layer thick NiO ski
Solospun : the long staple weavable singles yarn
SolospunTM is a spinning technology which provides the means to produce a singles yarn that can be successfully woven as either warp or weft. The technology is a versatile and cost effective alternative to two-folding, Sirospun or sizing. It offers significant benefits in terms of efficiency and productivity. SolospunTM is a simple, inexpensive, clip-on attachment for the spinning of long staple, weavable singles yarns. The technology is the result of a joint development between CSIRO Textile and Fibre Technology, The Woolmark Company and WRONZ and was commercially released in 1998. It is now successfully operating in worsted mills worldwide. The SolospunTM hardware consists of a pair of rollers held in a bracket, which is clipped onto the front of the pendulum-drafting arm. Each roller is positioned immediately below, and parallel to, each top front draft roller where it interacts with the emerging drafted fibre strand before twist insertion. The roller-fibre interaction subtly changes the structure of the yarn, which dramatically increases its abrasion resistance. This allows Solospun yarns to be woven without twofolding or sizing, providing significant cost savings. Depending on fabric structure, weaving performance is equivalent to that of conventional two-fold yarns. Fabrics woven from SolospunTM yarns are of good quality and appearance. Some aspects, including preferred hand and FAST results, are equal or superior to two-fold yarn fabrics. As with compact and condensed spinning, SolospunTM offers significant reductions in yarnhairiness. However, Solospun can be simply implemented on existing spinning frames and goes much further by making the singles yarns weavable.<br /
Derivation of the non-inferiority margin for the evaluation of direct oral anticoagulants in the treatment of venous thromboembolism
BACKGROUND: Direct oral anticoagulants that target a single coagulation factor have been developed as an alternative to standard therapies with heparin and/or vitamin K antagonists. The purpose of this study was to derive non-inferiority margins suitable for randomised clinical studies designed to evaluate these agents for the treatment of venous thromboembolism (VTE). METHODS: We performed a systematic review to derive non-inferiority margins suitable for use in studies evaluating direct oral anticoagulants for the treatment of VTE. A PubMed search identified publications that evaluated current standard treatment versus placebo, ‘no treatment’ or ‘less intensive treatment’ in patients with symptomatic deep vein thrombosis (DVT) and/or pulmonary embolism (PE). Publications were eligible if they had a randomised study design, included patients with symptomatic DVT and/or PE, used objective diagnostic methods to document the index event and reported objectively confirmed symptomatic recurrent VTE. RESULTS: Fourteen publications were included in the analysis. Recurrent VTE occurred in 25 (1.5%) out of 1715 patients who received current standard of care and in 157 (9.2%) out of 1711 patients who received placebo, ‘no treatment’ or ‘less intensive treatment’, for an odds ratio of 0.18 (95% confidence interval, 0.14−0.25; test for heterogeneity, p=0.87). In order to preserve 50% or 75% of the established treatment effect using a linear scale, the corresponding thresholds for non-inferiority equalled 2.50 and 1.75, respectively. CONCLUSIONS: This systematic review and statistical approach determined non-inferiority margins suitable for use in studies of direct oral anticoagulants for the treatment of DVT and/or PE
Adjustable Head Tube Angle Headset
This final design review report describes the design, manufacture, and test process of a bicycle headset capable of quickly and easily adjusting the effective head tube angle. The evolution of mountain bike geometry has forced bike designers to compromise between climbing and descending performance when choosing a head tube angle. A headset capable of quickly adjusting the effective head tube angle would allow riders to optimize their bike’s geometry for different stages of riding. This report details the research, idea generation, concept development and selection, design, manufacturing, and testing of our adjustable head tube angle headset
Вероятностно-детерминированная модель расчета безопасного расстояния при разливе топлива
В статье рассматриваются основные опасные факторы при эксплуатации автозаправочных станций, опасные факторы топливных жидкостей, их физические и физико-химические свойства. Основная задача в статье - проанализировать все возможные риски, возникающие при эксплуатации АЗС, выявить наиболее вероятные неблагоприятные события, способные привести к повреждениям и разрушениям АЗС. Проанализировать возможные сценарии развития аварии для выявления наиболее опасного. Данные исследования позволят в дальнейшем использовать математическую модель для определения радиуса поражения зданий, сооружений и населения, и определения безопасного расстояния для опасных объектов - АЗС.The article deals with the main hazards during the operation of gasoline stations, the dangerous factors of fuel fluids, their physical and physicochemical properties. The main task in the article is to analyze all possible risks arising from the operation of the filling station, to identify the most likely adverse events that can lead to damage and destruction of the filling stations. Analyze possible scenarios for the development of an accident to identify the most dangerous. The given researches will allow to use in the further mathematical model for definition of radius of destruction of buildings, constructions and the population, and definition of a safe distance for dangerous objects - the gas station
Tell me a story: The use of narrative as a learning tool about natural selection
Grounded within literature pointing to the value of narrative in communicating scientific information, the purpose of this study was to examine the use of stories as a tool for teaching about natural selection in the context of school science. The study utilizes a mixed method, case study approach which focuses on the design, implementation, and evaluation of narrative-based curriculum materials. The data consisted of questionnaires, classroom observations, and interviews with the students and teachers. The analysis of the data showed that most of the students developed adequate scientific understandings about natural selection and they perceived the narrative as easier to comprehend than the textbook. The findings speak to the need for examining ways of blending narrative effectively into science lessons
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