Outcomes of COVID-19 contact tracing in hospital healthcare workers: a retrospective cohort study

Objective: To determine risk-group-specific rate of becoming COVID-19-positive among healthcare workers having had contact with COVID-19 cases. Methods: The retrospective cohort study was conducted at the Ege University Hospital, Bornova, Turkey, and comprised all healthcare workers who had come into contact with COVID-19 cases between March 11 and May 31, 2020. The contacts were classified as low-risk, medium-risk and high-risk using the guidelines of the Turkish Ministry of Health. The outcome measures were the incidence of infection among contacts and the incubation period and serial interval among the new cases. Data was analysed using SPSS 23. Results: Of the 845 cases, 312(37%) had high risk, 263(31%) medium and 270(32%) low. Overall, there were 490(58%) females, 355(41%) males, 565(67%) aged <40 years, and 277(33%) aged >40 years. Of the total, 27(3.20%) healthcare workers tested COVID-19-positive and distribution among the risk-based groups was significant (p=0.037). There was a significantly increased risk of incidence among repeated contacts, no mask use, and the source being a colleague (p<0.05). Conclusion: The detection of high-risk contacts was found to be important for controlling COVID-19 infection in a hospital setting. Key Words: SARS-CoV-2, Healthcare workers, Contact tracing, Contact-based surveillance. Continuous...

Kinetics Solvent Effect and Mechanism of Hydrolysis of Ethyl Caprylate Ester in Aqueous Organic Solvent Media

The specific rate constant of ethyl caprylate in alkali catalised hydrolysis in water-acetone mixture covering range of 30 to 70% (v/v) of acetone has been determined at temperature 20 to 400c. The rate of reaction decreases with increase in percentage of Acetone from 30 to 70% (v/v). The observed Activation energy decreases progressively with increase in acetone content of the medium. The effect of molar concentration of water and Dielectric constant on the reaction kinetic has also been studied. The thermodynamic parameters (DG*, DH* and DS*) has been determined which showed strong dependency on solvent composition.

Experimental study on two-body and three-body abrasive wear behaviour of jute-natural rubber flexible green composite

The use of laboratory testing has become more significant to assess abrasion resistance in flexible reinforcement of armour and car structural components. In this study, compliant composite with constituents as woven jute fabric and natural rubber (NR) encapsulated in an NR-based B stage cured prepreg were tested for wear due to abrasion under two- and three-body conditions. Flexible composites are fabricated in three different configurations namely Jute/Rubber/Jute (JRJ), Jute/Rubber/Rubber/Jute (JRRJ) and Jute/Rubber/Jute/Rubber/Jute (JRJRJ). The present study makes use of abrasive paper with a grit size of 60 and silica sand with size 250 µm as the abrasive medium for two- and three-body abrasion tests respectively and the specific rate of wear is calculated. Though the wear trend of the composites follows a similar pattern in the case of two- and three-body wear, the mechanisms governing the wear are found to be different. The morphology of the worn surface is studied with the aid of a scanning electron microscope.

The Alkaline solvolysis of allyl bromide in alcohol-water solvents

<p>The rate of the alkaline solvolysis of allyl bromide has been measured in various ethanol-water and methanol-water mixtures. This has been found to increase with increase in solvent polarity. An attempt was made to explain this behaviour in terms of partial ionisation of the substrate. It has been suggested that in nucleophilic substitution the individual specific rate constants for attack by alkoxide or hydroxide ions are a better indication of solvent effects than the apparent overall rate constant.</p>

The Alkaline solvolysis of allyl bromide in alcohol-water solvents

<p>The rate of the alkaline solvolysis of allyl bromide has been measured in various ethanol-water and methanol-water mixtures. This has been found to increase with increase in solvent polarity. An attempt was made to explain this behaviour in terms of partial ionisation of the substrate. It has been suggested that in nucleophilic substitution the individual specific rate constants for attack by alkoxide or hydroxide ions are a better indication of solvent effects than the apparent overall rate constant.</p>

The influence of the type of nut raw materials on the processes of migration of fats in glazed candies with pralin bodies

Целью исследования являлось изучение влияния свойств орехового сырья на направление и скорость процессов миграции жиров в глазированных конфетах с пралиновыми корпусами. Исследование процессов миграции жиров между корпусом и глазурью в процессе хранения необходимо для прогнозирования сохранности и предотвращения органо-лептической порчи в результате осветления или умягчения глазури, а также «поседения» поверхности изделий. Предложен подход прогнозирования скорости процессов миграции жиров при хранении конфет с корпусами, изготовленными на основе орехового сырья, с использованием удельной скорости миграции жиров. Исследованы процессы миграции жиров в модельных образцах конфет с пралиновыми корпусами на основе арахиса, фундука, кешью, миндаля, покрытых глазурью с использованием заменителя масла какао лауринового типа при температуре хранения 18 °С. Показано, что удельная скорость миграции олеиновой кислоты на поверхность модельных образцов глазированных конфет с корпусами на основе арахиса превышает скорость миграции в конфетах с корпусами на основе кешью приблизительно в 20 раз. Полученные закономерности позволяют установить дополнительные требования к качеству используемого жирового сырья для уменьшения скорости миграции жиров. The aim of the work - the investigation of the influence of nut raw material properties on the direction and speed of fat migration processes in glazed sweets with praline cases. The study of fat migration processes between the body and the glaze during storage is necessary to predict the safety and prevent organoleptic spoilage as a result of lightening or softening of the glaze, as well as «graying» of the surface of the products. An approach to predicting the rate of fat migration processes during the storage of sweets with cases made on the basis of nut raw materials using the specific rate of fat migration is proposed. The processes of fat migration in model samples of sweets with praline cases based on peanuts, hazelnuts, cashews, almonds, glazed with glaze, with the use of a lauric-type cocoa butter substitute were investigated at a storage temperature of 18 °C. It is shown that the specific rate of migration of oleic acid to the surface of model samples of glazed sweets with peanut-based cases exceeds the migration rate in sweets with cashew-based cases by approximately 20 times. The obtained regularities allow us to establish additional requirements for the quality of the fat raw materials used to reduce the rate of fat migration.

Nano-Sized NiO Immobilized on Au/CNT for Benzyl Alcohol Oxidation: Influences of Hybrid Structure and Interface

Tiny gold nanoparticles were successfully anchored on carbon nanotubes (CNT) with NiO decoration by a two-step synthesis. Characterizations suggested that Ni species in an oxidative state preferred to be highly dispersed on CNT. During the synthesis, in situ reduction by NaBH4 and thermal treatment in oxidation atmosphere were consequently carried out, causing the formation of Au-Ni-Ox interfaces and bimetal hybrid structure depending on the Ni/Au atomic ratios. With an appropriate Ni/Au atomic ratio of 8:1, Ni atoms migrated into the sub-layers of Au particles and induced the lattice contraction of Au particles, whilst a higher Ni/Au atomic ratio led to the accumulation of NiO fractions surrounding Au particles. Both contributed to the well-defined Au-Ni-Ox interface and accelerated reaction rates. Nickel species acted as structure promoters with essential Au-Ni-Ox hybrid structure as well as the active oxygen supplier, accounting for the enhanced activity for benzyl alcohol oxidation. However, the over-layer of unsaturated gold sites easily occured under a high Ni/Au ratio, resulting in a lower reaction rate. With an Au/Ni atomic ratio of 8:1, the specific rate of AuNi8/CNT reached 185 μmol/g/s at only 50 °C in O2 at ordinary pressure.

Flatten the curve: Empirical evidence on how non-pharmaceutical interventions substituted pharmaceutical treatments during COVID-19 pandemic

During the outbreak of the COVID-19 pandemic, Non-Pharmaceutical and Pharmaceutical treatments were alternative strategies for governments to intervene. Though many of these intervention methods proved to be effective to stop the spread of COVID-19, i.e., lockdown and curfew, they also posed risk to the economy; in such a scenario, an analysis on how to strike a balance becomes urgent. Our research leverages the mobility big data from the University of Maryland COVID-19 Impact Analysis Platform and employs the Generalized Additive Model (GAM), to understand how the social demographic variables, NPTs (Non-Pharmaceutical Treatments) and PTs (Pharmaceutical Treatments) affect the New Death Rate (NDR) at county-level. We also portray the mutual and interactive effects of NPTs and PTs on NDR. Our results show that there exists a specific usage rate of PTs where its marginal effect starts to suppress the NDR growth, and this specific rate can be reduced through implementing the NPTs.

Features of Hydrogen Reduction of Fe(CN)63− Ions in Aqueous Solutions: Effect of Hydrogen Dissolved in Palladium Nanoparticles

Preliminary saturation of 2.6 nm palladium nanoparticles with hydrogen accelerates the reduction of Fe(CN)63− ions in aqueous solution three to four-fold. An analytical equation was derived describing the hydrogen saturation of palladium nanoparticles and the dependence of their catalytic activity on the hydrogen content in the metal. The specific rate constants of reduction do not depend on the content of palladium nanoparticles in the solution. A change in the temperature and pH or stirring of the solution do not affect the rate of catalytic reaction. Approaches to optimization of palladium-catalyzed reactions involving hydrogen are substantiated.

Distinct ground state and activated state modes of spiking in forebrain neurons

Neuronal firing patterns have significant spatiotemporal variety with no agreed upon theoretical framework. Using a combined experimental and modeling approach, we found that spike interval statistics can be described by discrete modes of activity. A "ground state" (GS) mode of low-rate spiking is universal among forebrain excitatory neurons and characterized by irregular spiking at a cell-specific rate. In contrast, "activated state" (AS) modes consist of spiking at characteristic timescales and regularity and are specific to neurons in a given region and brain state. We find that the majority of spiking is contributed by GS mode, while neurons can transiently switch to AS spiking in response to stimuli or in coordination with population activity patterns. We hypothesize that GS spiking serves to maintain a persistent backbone of neuronal activity while AS modes support communication functions.