High-pressure study on calcium azide(Ca(N_(3))_(2)):Bending of azide ions stabilizes the structure

The high-pressure structure and elastic properties of calcium azide(Ca(N_(3))_(2))were investigated using in-situ highpressure x-ray diffraction and Raman scattering up to 54 GPa and 19 GPa,respectively.The compressibility of Ca(N_(3))_(2)changed as the pressure increased,and no phase transition occurred within the pressure from ambient pressure up to 54 GPa.The measured zero-pressure bulk modulus of Ca(N_(3))_(2)is higher than that of other alkali metal azides,due to differences in the ionic character of their metal-azide bonds.Using CASTEP,all vibration modes of Ca(N_(3))_(2)were accurately identified in the vibrational spectrum at ambient pressure.In the high-pressure vibration study,several external modes(ext.)and internal bending modes(ν_(2))of azide anions(N_(3)^(-))softened up to~7 GPa and then hardened beyond that pressure.This evidence is consistent with the variation observed in the F_(E)–f_(E)data analyzed from the XRD result,where the slope of the curve changes at 7.1 GPa.The main behaviors under pressure are the alternating compression,rotation,and bending of N_(3)^(-)ions.The bending behavior makes the structure of Ca(N_(3))_(2)more stable under pressure.

The protective effects of a D-tetra-peptide hydrogel adjuvant vaccine against H7N9 influenza virus in mice

Repeated waves of influenza virus H7N9 epidemics after 2013 have caused severe influenza in humans,with mortality reaching approximately 40%–50%.To prevent possible pandemics,the development of highly effective vaccines against influenza virus H7N9 is highly desired.In the present study,by taking advantage of the D-tetra-peptide adjuvant(G^(D)F^(D)F^(D)Y),we reported a simple method to prepare H7N9 vaccines.Naproxen(Npx),with good anti inflammatory and broad anti-viral effects,was employed as an N-terminal capping group to construct a hydrogel precursor,Npx-G^(D)F^(D)F^(D)Y.The hydrogel adjuvant was prepared using a routine heating cooling protocol and the final vaccine was ready after mixing with the split A/Zhejiang/DTID-ZJU01/2013(H7N9)antigen by vortexing.Compared with the traditional Al(OH)_(3) adjuvant vaccine and the split vaccine,our hydrogel adjuvant vaccine showed the best preventive effects against H7N9 infection.A mechanistic study illustrated that higher antibody responses and variations in cytokine expression might account for its increased protective effects.Our strategy demonstrated the advantages of a peptide hydrogel adjuvant in the application of vaccines against H7N9 and demonstrated its potential application in vaccines against emerging threats from other viruses.

Research progress on human infection with avian influenza H7N9

Since the first case of novel H7N9 infection was reported,China has experienced five epidemics of H7N9.During the fifth wave,a highly pathogenic H7N9 strain emerged.Meanwhile,the H7N9 virus continues to accumulate mutations,and its affinity for the human respiratory epithelial sialic acid 2-6 receptor has increased.Therefore,a pandemic is still possible.In the past 6 years,we have accumulated rich experience in dealing with H7N9,especially in terms of virus tracing,epidemiological research,key site mutation monitoring,critical disease mechanisms,clinical treatment,and vaccine development.In the research fields above,significant progress has been made to effectively control the spread of the epidemic and reduce the fatality rate.To fully document the research progress concerning H7N9,we reviewed the clinical and epidemiological characteristics of H7N9,the key gene mutations of the virus,and H7N9 vaccine,thus providing a scientific basis for further monitoring and prevention of H7N9 influenza epidemics.

Extrapolation Cascadic Multigrid Method for Cell-Centered FV Discretization of Diffusion Equations with Strongly Discontinuous and Anisotropic Coefficients

Extrapolation cascadic multigrid(EXCMG)method with conjugate gradient smoother is very efficient for solving the elliptic boundary value problems with linearfinite element discretization.However,it is not trivial to generalize the vertex-centred EXCMG method to cell-centeredfinite volume(FV)methods for diffusion equations with strongly discontinuous and anisotropic coefficients,since a non-nested hierarchy of grid nodes are used in the cell-centered discretization.For cell-centered FV schemes,the vertex values(auxiliary unknowns)need to be approximated by cell-centered ones(primary unknowns).One of the novelties is to propose a new gradient transfer(GT)method of interpolating vertex unknowns with cell-centered ones,which is easy to implement and applicable to general diffusion tensors.The main novelty of this paper is to design a multigrid prolongation operator based on the GT method and splitting extrapolation method,and then propose a cell-centered EXCMG method with BiCGStab smoother for solving the large linear system resulting from linear FV discretization of diffusion equations with strongly discontinuous and anisotropic coefficients.Numerical experiments are presented to demonstrate the high efficiency of the proposed method.

Severe Anemia in a Patient With Mild T Cell Hypofunction Infected With Parvovirus B19

Background Parvovirus B19 is a single-stranded DNA virus with a 5.6 kilobase DNA genome and a diameter of 22–24nm.1 This virus does not possess an envelope and it is the most pathogenic virus belonging to the family of Parvoviridae that infects human beings.2 The main diseases caused by parvovirus B19 are as follows:(1)infectious erythema(also known as fifth disease,erythema infection),a cause of a common rash in pediatric patients;(2)joint disease;(3)aplastic anemia crisis in patients with chronic hemolytic disease;(4)chronic anemia in immunodeficient patients;(5)fetal hydrops in addition to stillbirth and abortion(fetal death).