Synthesis methods and applications of high entropy nanoparticles

High-entropy alloys(HEAs) are an important research direction in the materials science field and engineering field.Different from traditional alloys which usually contain only one basic element and infrequently two,HEAs are made up of many major elements in much larger numbers.With impressive mechanical properties,impressive corrosion resistance and superior thermal stability,HEAs offer overwhelming advantages over conventional alloys.HEAs have received a lot of attention due to its unique concept and performance.In recent years,many researchers have prepared HEAs at the nanometer level,and the obtained high-entropy nanoparticles(HEA-NPs) have been extensively used in multifarious fields.This paper reviews the main characteristics,core effects,conventional synthesis methods and their applications in various fields of HEA-NPs.Furthermore,the vast space to be explored is discussed and the future development direction and outlook are outlined productively.

Factors associated with a SARS-CoV-2 recurrence after hospital discharge among patients with COVID-19:systematic review and meta-analysis

Background:The proportion of recurrences after discharge among patients with coronavirus disease 2019(COVID-19)was reported to be between 9.1%and 31.0%.Little is known about this issue,however,so we performed a meta-analysis to summarize the demographical,clinical,and laboratorial characteristics of non-recurrence and recurrence groups.Methods:Comprehensive searches were conducted using eight electronic databases.Data re-garding the demographic,clinical,and laboratorial characteristics of both recurrence and non-recurrence groups were extracted,and quantitative and qualitative analyses were conducted.Results:Ten studies involving 2071 COVID-19 cases were included in this analysis.The proportion of recurrence cases involving patients with COVID-19 was 17.65%(between 12.38%and 25.16%)while older patients were more likely to experience recurrence(weighted mean difference(WMD)=1.67,range between 0.08 and 3.26).The time from discharge to recurrence was 13.38 d(between 12.08 and 14.69 d).Patients were categorized as having moderate severity(odds ratio(OR)=2.69,range between 1.30 and 5.58),while those with clinical symptoms including cough(OR=5.52,range between 3.18 and 9.60),sputum production(OR=5.10,range between 2.60 and 9.97),headache(OR=3.57,range between 1.36 and 9.35),and diz-ziness(OR=3.17,range between 1.12 and 8.96)were more likely to be associated with recurrence.Patients pre-senting with bilateral pulmonary infiltration and decreased leucocyte,platelet,and CD4+T counts were at risk of COVID-19 recurrence(OR=1.71,range between 1.07 and 2.75;WMD=?1.06,range between?1.55 and?0.57,WMD=?40.39,range between?80.20 and?0.48,and WMD=?55.26,range between?105.92 and?4.60,respectively).Conclusions:The main factors associated with the recurrence of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)after hospital discharge were older age,moderate severity,bilateral pulmonary infiltration,laboratory findings including decreased leucocytes,platelets,and CD4+T counts,and clinical symptoms including cough,sputum production,headache,and dizziness.These factors can be considered warning indicators for the recurrence of SARS-CoV-2 and might help the development of specific management strategies.

Synthesis and Characterization of Self-oscillating P(AA-co-AM)/PEG SemiIPN Hydrogels Based on a p H Oscillator in Closed System

Various semi-interpenetrating polymer network（semi-IPN） hydrogels composed of pore-forming agent polyethylene glycol（PEG）, acrylic acid（AA） and acrylamide（AM） were prepared by using free radical polymerization with a two-step method. The chemical structures of the synthesized hydrogels were characterized by FTIR spectroscopy and the morphologies were studied by scanning electron microscopy（SEM） method. The swelling properties, such as the p Hresponsive behavior, salt sensitivity, oscillatory swelling/de-swelling behaviors in different solutions with various p H values and self-oscillating behaviors in bath p H oscillator were investigated in detail. The results revealed that the prepared hydrogels exhibited high p H sensitivity and excellent salt sensitivity when the p H values of the medium changes from 3.0 and 7.0 and well reversible properties by undergoing a number of swelling/de-swelling recycles. In particular, the hydrogels exhibited self-oscillation behavior in a closed system containing Br O3？-SO32？-Fe（CN）64？-H＋. This study may create a new possibility as biomaterial for new self-walking actuators and other devices.