Van der Waals heterostructures of SiC and Janus MSSe (M = Mo,W) monolayers: a first principles study

Favorable stacking patterns of two models with alternative orders of chalcogen atoms in SiC-MSSe (M = Mo, W) vdW heterostructures are investigated using density functional theory calculations. Both model-I and model-II of the SiC-MSSe (M = Mo, W) vdW heterostructures show type-II band alignment, while the spin orbit coupling effect causes considerable Rashba spin splitting. Furthermore, the plane-average electrostatic potential is also calculated to investigate the potential drops across the heterostructure and work function. The imaginary part of the dielectric function reveals that the first optical transition is dominated by excitons with high absorption in the visible region for both heterostructures. Appropriate band alignments with standard water redox potentials enable the capability of these heterostructures to dissociate water into H⁺/H₂ and O₂/H₂O.

Using DFT calculations, we have investigated the electronic structure, Rashba effect, optical and photocatalytic performance of SiC-MSSe (M = Mo, W) van der Waals heterostructures with different stacking patterns of chalcogen atoms.     

Transition metal- and catalyst-free one-pot green method for the synthesis of N-sulfonyl amidines via direct reaction of sulfonyl azides with amines

In this report, a green synthesis of N-sulfonyl amidines via the direct reaction of tertiary or secondary amines with sulfonyl azides is described. Transition metal- and catalyst-free conditions were used for the synthesis of biologically important N-sulfonyl amidines. Further studies showed that the reaction proceeded via in situ aerobic oxidation of amines under reflux conditions.

A green synthesis of N-sulfonyl amidines via the direct reaction of tertiary or secondary amines with sulfonyl azides.     

Molecularly imprinted polymeric coatings for sensitive and selective gravimetric detection of artemether

Monitoring antimalarial drugs is necessary for clinical assays, human health, and routine quality control practices in pharmaceutical industries. Herein, we present the development of sensor coatings based on molecularly imprinted polymers (MIPs) combined with quartz crystal microbalance (QCM) for sensitive and selective gravimetric detection of an antimalarial drug: artemether. The MIP coatings are synthesized by using artemether as the template in a poly(methacrylic acid-co-ethylene glycol dimethacrylate) matrix. Artemether-MIP and the non-imprinted polymer (NIP) control or reference layers are deposited on 10 MHz dual-electrode QCM by spin coating (187 ± 9 nm layer thickness after optimization). The coatings are characterized by FTIR spectroscopy and atomic force microscopy that reveal marked differences among the MIP and NIP. The MIP-QCM sensor exhibits high sensitivity (0.51 Hz ppm⁻¹) with sub-10 ppm detection and quantification limits. The MIP-QCM sensor also exhibits a 6-fold higher sensitivity compared to the NIP-QCM, and a dynamic working range of 30–100 ppm. The response time of MIP-QCM devices for a single cycle of analyte adsorption, signal saturation, and MIP regeneration is less than 2.5 min. The sensor also demonstrates selectivity factors of artemether-MIP of 2.2 and 4.1 compared to artemisinin and lumefantrine, respectively. Reversibility tests reveal less than 5% variation in sensor responses over three cycles of measurements at each tested concentration. The MIP-QCM showed lower detection limits than conventional HPLC-UV, and faster response time compared to HPLC-UV and liquid chromatography-mass spectrometry (LC-MS).

Chemical structures of the antimalarial drugs: artemisinin, artemether (a methyl ether derivative of artemisinin), and lumefantrine.     

First-Phase Ejection Fraction Is a Powerful Predictor of Adverse Events in Asymptomatic Patients With Aortic Stenosis and Preserved Total Ejection Fraction

Objectives

This study investigated the prognostic value of first-phase ejection fraction (EF1) in patients with aortic stenosis (AS), a condition in which left ventricular dysfunction as measured by conventional indices is an indication for valve replacement.

β-Hydroxybutyrate protects from alcohol-induced liver injury via a Hcar2-cAMP dependent pathway

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Work-related musculoskeletal disorders among dental professionals in Saudi Arabia

[Purpose] Musculoskeletal disorders are common causes of work-related disability in different professions involving the frequent practice of lifting, stooping, twisting, prolonged sitting, or standing. The dental profession is one such profession. Our aim was to determine the prevalence of work-related musculoskeletal disorders among dental professionals in Saudi Arabia, the factors associated with them, and their consequences and to propose preventive measures for them. [Subjects and Methods] A self-administered online questionnaire was sent to 225 members of the Saudi Dental Association. It included questions on demographic and professional characteristics, general medical history, and history of work-related musculoskeletal disorders before and after joining the dental profession. [Results] The questionnaire was completed by 65% of the respondents. Among them 85% reported that they had developed some pain due to work after joining the dental profession, and 42% reported that they were suffering pain at the time of the survey. Besides lower back, shoulder, and neck regions, the hands, upper back, and other regions like the elbows, buttocks, thighs, leg, and feet were areas in which they pain. [Conclusion] The prevalence of work-related musculoskeletal disorders among dental professionals in Saudi Arabia is high, affecting their daily activities, sometimes even forcing them to change their work setting. Age, gender, specialty of work, work setting, number of contact hours with patients, etc., were all found to be related to their work-related pain. We need to emphasize the role of ergonomics, counseling, proper techniques of patient handling, etc., during the training of dental professionals so that they can work efficiently.Key words: Work-related musculoskeletal disorders, Dentists, Saudi Arabia