Preparation of new hydrogels by visible light cross-linking of dextran methacrylate and poly(ethylene glycol)-maleic acid copolymer.

In this work, a series of new biodegradable and biocompatible hydrogels were synthesized by photopolymerization of dextran-methacrylate (DXM) with poly(ethylene glycol)-maleic acid copolymer (poly(PEG-co-MA, PEGMA)) using (-)-riboflavin as a visible light photoinitiator and L-arginine as a co-photoinitiator. DXM was prepared by acylation of dextran (DX) with methacryloyl chloride (MAC), and PEGMA was synthesized by polycondensation of poly(ethylene glycol) (PEG) and maleic acid (MA). The DXM and PEGMA were characterized by FT-IR and HNMR spectroscopy.

Students' attitude and sleep pattern during school closure following COVID-19 pandemic quarantine: a web-based survey in south of Iran.

Background: School closure is one of the main policies of global health care strategies performed worldwide. Despite all benefits, there might be some threats for younger groups spending their time in quarantine. This study aims to determine the impacts of lockdown and school closure on children's major lifestyle aspects, especially their leisure and sleep pattern during the COVID-19 pandemic.

Evaluation of students' attitude and emotions towards the sudden closure of schools during the COVID-19 pandemic: a cross-sectional study.

Background: Rapid increases in the number of COVID-19 cases have led to the closure of academic institutions including elementary and high schools. The absence from the educational environment can affect the students' emotions towards education and school attendance. In this study, we aimed to evaluate the students' attitude and emotions towards the sudden closure of schools during the COVID-19 pandemic.