Preparation and bioactivity of sol-gel macroporous bioactive glass

Bioactive glass is well known for its ability of bone regeneration, and sol-gel bioactive glass has many advantages compared with melt-derived bioactive glass. 3-D scaffold prepared by the sol-gel method is a promising substrate material for bone tissue engineering and large-scale bone repair. Porous sol-gel glass in the CaO-SiO2-P205 system with macropores larger than 100 μm was prepared by the addition of stearic acid as a pore former. The diameter of the pore created by the pore former varied from 100 to 300 μm. The formation of a hydroxyapatite layer on the glass was analyzed by studying the surface of the porous glass by scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, and Raman spectra after they had been immersed in simulated body fluid （SBF） for some time, and the porous glass shows good bioactivity.

Exact Controllability for the Fourth Order Schrdinger Equation

The boundary controllability of the fourth order Schrdinger equation in a bounded domain is studied.By means of an L 2-Neumann boundary control,the authors prove that the solution is exactly controllable in H-2(Ω) for an arbitrarily small time.The method of proof combines both the HUM(Hilbert Uniqueness Method) and multiplier techniques.

Assessment of infectivity and the impact on neutralizing activity of immune sera of the COVID-19 variant,CAL.20C

Dear Editor,New variants of SARS-CoV-2 have been emerging since the initial outbreak in 2019;1 one of the latest ones was identified in Southern California in October 2020 and was subsequently detected in 26 other states in the United States as well as other countries as of January 2021.

The SARS-CoV-2 spike L452R-E484Q variant in the Indian B.1.617 strain showed significant reduction in the neutralization activity of immune sera

To assess the impact of the key non-synonymous amino acid substitutions in the RBD of the spike protein of SARS-CoV-2 variant B.1.617.1(dominant variant identified in the current India outbreak)on the infectivity and neutralization activities of the immune sera,L452R and E484Q(L452R-E484Q variant),pseudotyped virus was constructed(with the D614G background).The impact on binding with the neutralizing antibodies was also assessed with an ELISA assay.Pseudotyped virus carrying a L452R-E484Q variant showed a comparable infectivity compared with D614G.However,there was a significant reduction in the neutralization activity of the immune sera from non-human primates vaccinated with a recombinant receptor binding domain(RBD)protein,convalescent patients,and healthy vaccinees vaccinated with anmRNA vaccine.In addition,there was a reduction in binding of L452R-E484Q-D614G protein to the antibodies of theimmune sera fromvaccinated nonhuman primates.These results highlight the interplay between infectivity and other biologic factors involved in the natural evolution of SARS-CoV-2.Reduced neutralization activities against the L452R-E484Q variant will have an impact on health authority planning and implications for the vaccination strategy/newvaccine development.

Overexpression of Hdac6 extends reproductive lifespan in mice

Dear Editor, Histone deacetylase 6 （Hdac6） was discovered as a deacetylase of e-tubulin and functions in cell migration, immunity and resistance to virus infection in vitro （Hubbert et al., 2002; Valenzuela-Fernandez et al., 2008）. Overexpression of Hdac6 enhances resistance to virus infection in embryonic stem （ES） cells and in mice （Wang et al., 2015）. Hdac6 also can function to deacetyiate protein and is involved in protein ubiquitination and degradation （Seigneurin-Berny et al., 2001; Zhang et al., 2014）, and self- clearance of misfolded proteins, promoting autophagy and preventing neurodegeneration （Lee et al., 2010; Pandey et al., 2007）. HDAC6 also is implicated in DNA damage response and depletion or inhibition of HDAC6 induces DNA damage and apoptosis （Namdar et al., 2010; Zhang et al., 2014）, suggesting that HDAC6 could be important for DNA repair and integrity maintenance.

Heterologous mRNA vaccine booster increases neutralization of SARS-CoV-2 Omicron BA.2 variant

Dear Editor,Emerging epidemiology data indicate that the Omicron BA.2 sublineage is expected to become the dominant strain owing to its enhanced transmissibility.1 The BA.1 sublineage reduced the efficacy of neutralizing antibodies.2,3 The BA.2 sublineage may possess similar neutralizing antibody evasion.3 However,booster(3rd dose)vaccination strategies,or three exposures to the SARS-CoV2 spike protein through natural infection elicits strong neutralizing antibody responses.This raises the question of whether booster doses also elicit neutralizing antibody responses against BA.2.We present in this study the neutralization activity of serum from human recipients of homologous booster(three doses of CoronaVac inactivated vaccine)or heterologous booster(inactivated vaccine priming dose with BnT162b2 third dose)vaccine regimens against pseudovirus containing the Omicron BA.2 spike protein.We also evaluated the neutralizing activities of 6 monoclonal antibodies,and serum from monkeys vaccinated with a recombinant RBD protein vaccine.Finally,we also evaluated cell entry mediated by the Omicron BA.2 spike protein.