Semiclassical Transition State Theory (SCTST) Rate Coefficients for the Unimolecular Decomposition of the Ethoxy (CHCHO) Radical.

The thermal unimolecular decay of ethoxy is important in high-temperature combustion environments where the ethoxy radical is a key reactive intermediate. Two dissociation pathways of ethoxy, including the β-C-C scission to yield CH + CHO and the H-elimination to make H + CHCHO, were characterized using a high-level coupled-cluster-based composite quantum chemical method (mHEAT-345(Q)). The former route is found to be dominant while the latter is insignificant, in agreement with previous experimental and theoretical studies.

Nonstatistical Unimolecular Decay of the CHOO Criegee Intermediate in the Tunneling Regime.

Unimolecular decay of the formaldehyde oxide (CHOO) Criegee intermediate proceeds via a 1,3 ring-closure pathway to dioxirane and subsequent rearrangement and/or dissociation to many products including hydroxyl (OH) radicals that are detected. Vibrational activation of jet-cooled CHOO with two quanta of CH stretch (17-18 kcal mol) leads to unimolecular decay at an energy significantly below the transition state barrier of 19.46 ± 0.

Rare Cause of Gastrointestinal Bleeding: A Case Report of Pancreatic Arteriovenous Malformation.

BACKGROUND Arteriovenous malformation is an unusual cause of gastrointestinal bleeding, particularly in the pancreas. A definitive treatment strategy is not yet established. CASE REPORT We present the case of a 37-year-old man with underlying hypertension and no significant family history who presented with a 3-month history of intermittent epigastric pains and unintentional weight loss of 5 kg in 2 months.

Methanediol from cloud-processed formaldehyde is only a minor source of atmospheric formic acid.

Atmospheric formic acid is severely underpredicted by models. A recent study proposed that this discrepancy can be resolved by abundant formic acid production from the reaction (1) between hydroxyl radical and methanediol derived from in-cloud formaldehyde processing and provided a chamber-experiment-derived rate constant, = 7.5 × 10 cm s.

A sensorless anti-windup speed control approach to axial gap bearingless motors with nonlinear lumped mismatched disturbance observers.

In this paper, sensorless robust speed control with nonlinear lumped mismatched disturbance observers for a permanent magnet type axial gap bearingless motor (AGBM) is designed. Multistage anti-windup-based dynamic surface control combined with integral backstepping control is proposed to control the motor's axial displacement and rotor speed. The approach is against parameter uncertainties and external disturbances, improving steady-state accuracy, eliminating the derivative explosion phenomenon, no chattering problem, and reducing the magnitude of the control system when current saturation occurs.

Willingness and attitudes of parents towards COVID-19 vaccines for children in Vietnam.

Background: With an increasing need for COVID-19 vaccination around the globe, we aim to investigate willingness and attitudes of parents regarding COVID-19 vaccines for children in Vietnam.

Method: A 24-item online survey was conducted among 602 parents and legal guardians of children under 18 years of age.

Results: There were 82.

Antimicrobial and Flame-Retardant Coatings Prepared from Nano- and Microparticles of Unmodified and Nitrogen-Modified Polyphenols.

The purpose of this study was to elucidate the structures and functional properties of tannin- and lignin-derived nano- and microparticles and the coatings prepared from them. Nanoparticles prepared from technical lignins and water-insoluble tannin obtained from softwood bark showed large differences in the suspension testing of antibacterial efficacy against methicillin-resistant (MRSA) bacteria. A common factor among the most effective lignin nanoparticles was a relatively low molar mass of the lignin, but that alone did not guarantee high efficacy.

Vietnam Association of Gastroenterology (VNAGE) consensus on the management of infection.

infection is prevalent and has a rapidly increasing antibiotic resistance rate in Vietnam. Reinfection is quite common, and gastric carcinoma remains one of the most common malignancies, which is not uncommon to develop after successful eradication. The purpose of this consensus is to provide updated recommendations on the management of infection in the country.

High-accuracy first-principles-based rate coefficients for the reaction of OH and CHOOH.

The ˙OH-initiated oxidation of methyl hydroperoxide, which plays an important role in the atmospheric chemistry of methane, was theoretically characterized using high-accuracy composite amHEAT-345(Q) coupled-cluster calculations followed by a two-dimensional , resolved master equation analysis. The reaction is found to proceed through two distinct hydrogen-bonded pre-reactive complexes leading to two product channels, in accord with the experimental observations: (i) ˙OH + CHOOH → CHOO˙ + HO with a yield of 0.8 ± 0.

Tobacco and electronic cigarette smoking among in-school adolescents in Vietnam between 2013 and 2019: prevalence and associated factors.

Background: Smoking among adolescents in schools is a major global public health concern. There is limited evidence regarding prevalence and associated factors in Vietnam.

Objective: To compare the prevalence of smoking and associated factors among in-school adolescents aged 13-17 years in Vietnam between 2013 and 2019.

Mechanism, thermochemistry, and kinetics of the reversible reactions: CH + H ⇌ CH + H ⇌ CH.

High-level coupled cluster theory, in conjunction with Active Thermochemical Tables (ATcT) and ,-resolved master equation calculations, was used in a study of the title reactions, which play an important role in the combustion of hydrocarbons. In the set of radical/radical reactions leading to soot formation in flames, the addition of H-atoms to alkenes is likely a common reaction, triggering the isomerization of complex hydrocarbons to aromatics. The heats of formation of CH, CH, and CH are established to be 301.

Reaction of Methylidyne with Ethane: The C-C Insertion Is Unimportant.

High-accuracy coupled-cluster calculations in combination with the ,-resolved master-equation analysis are used to study the reaction mechanism and kinetics of methylidyne with ethane. This reaction plays an important role in the combustion of hydrocarbon fuels and in interstellar chemistry. Two distinct mechanisms, the C-C and the C-H insertions of CH in CH, are characterized.

Probing the Exit Channel of the OH + CHOH → HO + CHO Reaction by Photodetachment of CHO(HO).

Transition state dynamics of bimolecular reactions can be probed by photodetachment of a precursor anion when the Franck-Condon region of the corresponding neutral potential energy surface is near a saddle point. In this study, photodetachment of anions at / = 49 enabled investigation of the exit channel of the OH + CHOH → HO + CHO reaction using photoelectron-photofragment coincidence spectroscopy. High-level coupled-cluster calculations of the stationary points on the anion surface show that the methoxide-water cluster CHO(HO) is the stable minimum on the anion surface.

Violence and non-fatal injuries among Vietnamese in-school adolescents: national prevalence estimates and associated factors.

School violence and injury are major public health problems worldwide. The data of this study were from the Viet Nam Global School-based Student Health Survey (GSHS) - a nationally representative survey conducted in 2019, with a sample size of 7690 students aged 13-17 years old. We found the prevalence of violence and non-fatal injury to be 14.

Clustering Lifestyle Risk Behaviors among Vietnamese Adolescents and Roles of School: A Bayesian Multilevel Analysis of Global School-Based Student Health Survey 2019.

Background: Adolescence is a vulnerable period for many lifestyle risk behaviors. In this study, we aimed to 1) examine a clustering pattern of lifestyle risk behaviors; 2) investigate roles of the school health promotion programs on this pattern among adolescents in Vietnam.

Methods: We analyzed data of 7,541 adolescents aged 13-17 years from the 2019 nationally representative Global School-based Student Health Survey, conducted in 20 provinces and cities in Vietnam.

Thermal Decomposition of CHO: A Curious Case of Pressure-Dependent Tunneling Effects.

The thermal unimolecular decomposition of a methoxy radical (CHO), a key intermediate in the combustion of methane, methanol, and other hydrocarbons, was studied using high-level coupled-cluster calculations, followed by ,-resolved master equation analyses. The experimental results available for a wide range of temperature and pressure are in striking agreement with the calculations. In line with a previous theoretical study that used a one-dimensional master equation, the tunneling correction is found to exhibit a marked pressure dependence, being the largest at low pressure.

The CH(XΠ) + HO reaction: two transition state kinetics.

The reaction of ground state methylidyne (CH) with water vapor (H2O) is theoretically re-investigated using high-level coupled cluster computations in combination with semi-classical transition state theory (SCTST) and two-dimensional master equation simulations. Insertion of CH into a H-O bond of H2O over a submerged barrier via a well-skipping mechanism yielding solely H and CH2O is characterized. The reaction kinetics is effectively determined by the formation of a pre-reaction van der Waals complex (PRC, HC-OH2) and its subsequent isomerization to activated CH2OH in competition with PRC re-dissociation.

Image formation by a biological curved mirror array of the fisheye in the deep-sea environment.

In this paper, we present the imaging formation process of the piecewise mirror eyes of the deep-sea spookfish, which has a strange combination of refractive and reflective eyes. The biological reflective eye structure is formulated to the curved surface's flat mirror array. Zemax is utilized to evaluate optical features such as the modulation transfer function, distortion, and imaging performances.

Improvement in Compliance With Smoke-Free Environment Regulations at Hotels and Restaurants in Vietnam After an Administrative Intervention.

Introduction: Vietnam is among the countries with the highest smoking prevalence among male adults, as well as high prevalence of secondhand smoke exposure at indoor places. In many countries, including Vietnam, exposure to tobacco smoking is greatest in restaurants/bars and hotels. This study aims to analyze the compliance of hotels and restaurants to smoke-free environment regulations before and after an intervention.

Secondhand Tobacco Smoke Exposure in Indoor Workplaces in Viet Nam and Associated Factors: Findings from Two Rounds of Global Adult Tobacco Surveys (GATS) 2010 and 2015.

Objectives: This paper explores changes in the level of secondhand smoke (SHS) exposure at indoor workplaces between 2010 and 2015 in Viet Nam and the association between the exposure and various demographic factors, using data from Viet Nam's Global Adult Tobacco Surveys (GATS) 2010 and 2015.

Methods: Data was pooled from the two GATS surveys and analysed using descriptive and Poisson regression analyses.

Results: There was a highly statistically significant reduction in the level of SHS exposure at indoor workplaces from 55.

Pressure-Dependent Rate Constant Caused by Tunneling Effects: OH + HNO as an Example.

Tunneling effects on chemical reactions are well-known and have been unambiguously demonstrated by processes that involve the motion of hydrogen atoms at low temperature. However, the process by which tunneling effects cause a falloff curve (i.e.