Broadly neutralizing antibodies derived from the earliest COVID-19 convalescents protect mice from SARS-CoV-2 variants challenge

Coronavirus disease 2019(COviD-19)was first reported three years ago,when a group of individuals were infected with the original SARS-CoV-2 strain,based on which vaccines were developed.Here,we develop six human monoclonal antibodies(mAbs)from two elite convalescents in Wuhan and show that these mAbs recognize diverse epitopes on the receptor binding domain(RBD)and can inhibit the infection of SARS-CoV-2 original strain and variants of concern(VOCs)to varying degrees,including Omicron strains XBB and XBB.

Composition optimization of high-strength Mg-Gd-Y-Zr alloys based on the structural unit of Mg-Gd solid solution

Mg-Gd-Y-Zr alloys with high strength fall within narrow composition range.The present paper explains their composition rule by establishing the cluster-plus-glue-atom unit of Gd-containing Mg solid solution with the aid of Mg matrix and Mg_(5) Gd precipitate phase.First,based on the structural homologue between Gd-containing Mg solid solution and Mg_(5) Gd precipitate phase and in combination with our previously established method for calculating the glue atoms,[Gd-Mg_(12)]Mg_(5) is obtained as the chemical unit of Gd-containing Mg solid solution.Then,seven compositions are designed using different combinations of this unit and that of pure Mg[Mg-Mg_(12)Mg3.After a systematic experimental investigation on the microstructure and mechanical property evolutions as a function of the unit proportions,it is revealed that the Mg-10.1 Gd-3.3 Y-0.9 Zr alloy,being issued from equi-proportion mixing of the two units,shows the strongest tendency of precipitation and reaches the highest strength of 374 MPa after aging.The composition and strength of this alloy are quite close to GW103 K which is well recognized for its general mechanical performance in Mg-Gd-Y-Zr system.

Solute-homogenization model and its experimental verification in Mg-Gd-based alloys

Composition homogenization in solid solution is important for industrial alloys. In the present work, a solute homogenization model is proposed based on the chemical short-range-order tendency in Mg-Gd- based alloys. After a calculation using the cluster-plus-glue-atom model, the stable Mg-Gd structural unit is derived, [Gd-Mg12 ]Mg6, where one solute Gd is nearest-neighbored with twelve Mg atoms to form the characteristic hcp cluster [Gd-Mg12 ] and this cluster is matched with six Mg glue atoms. Such a local unit is then mixed with [Mg-Mg12 ]Mg3, the stable unit for pure Mg. Assuming that the Gd-containing units are arranged in fcc- or bcc-like lattice points and the Mg units in their octahedral interstices, three proportions between the two units are obtained, 1：1, 2：3, and 1：3, which constitute three solute homogenization modes. The prevailing Mg-Gd-based alloys are consequently classified into three groups, respectively exemplified by GW103 K （Mg-10Gd-3Y-0.4Zr, wt%）, GW83 K （Mg-SGd-3Y-0.4Zr）, and GW63 K （Mg-6Gd- 3Y-0.4Zr）. Mg-Gd-Y-Zr alloys were designed following the model （where Y and Zr were also added in substitution for Gd） and prepared by permanent-mould casting. According to their mechanical properties, the 1：3 alloy （Mg-5.9Gd-1.6Y-0.4Zr） shows the best comprehensive properties （ultimate tensile strength 305 MPa, yield strength 186 MPa, elongation 9.0%） in solution plus ageing state.2017 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science ＆ Technology.

NF-κB regulates brown adipocyte function through suppression of ANT2

The transcription factor nuclear factor of kappa-light-chain-enhancer of activated B cells(NF-κB)is expressed in brown adipocytes,but its role remains largely unknown in the cells.This issue was addressed in current study by examining NF-κB in brown adipocytes in vitro and in vivo.NF-κB activity was increased by differentiation of brown adipocytes through elevation of p65(RelA)expression.The transcriptional activity of NF-κB was induced by the cold stimulation with an elevation in S276 phosphorylation of p65 protein.Inactivation of NF-κB in brown adipocytes made the knockout mice[uncoupling protein 1(Ucp1)-CreER-p65^(f/f),U-p65-KO]intolerant to the cold environment.The brown adipocytes exhibited an increase in apoptosis,a decrease in cristae density and uncoupling activity in the interscapular brown adipose tissue(iBAT)of p65-KO mice.The alterations became severer after cold exposure of the KO mice.The brown adipocytes of mice with NF-κB activation(p65 overexpression,p65-OE)exhibited a set of opposite alterations with a reduction in apoptosis,an increase in cristae density and uncoupling activity.In mechanism,NF-κB inhibited expression of the adenine nucleotide translocase 2(ANT2)in the control of apoptosis.Data suggest that NF-κB activity is increased in brown adipocytes by differentiation and cold stimulation to protect the cells from apoptosis through down-regulation of ANT2 expression.