APPLICATION OF THE POSITRON ANNIHILATION TECHNIQUE

The principles of positron annihilation and four positron experimental techniques are described. The application of positron annihilation technique in material science. atomic physics and other related fields are discussed.

Expression of Structural Protein E2 of Hepatitis C Virus

The E2 glycoprotein is one of the structural components of the hepatitis C virus (HCV) virion. It elicits production of neutralising antibodies against the virus, and is involved in viral morphogenesis. The protein is considered as a major candidate for anti-HCV vaccine. Despite this, little is known about this protein. Previous studies have focused on the and functional analysis of the glycosylated forms. This report describes expression of the E2 (recE2) in different forms and in different expression systems in Escherichia coli cells and in mammalian cells in order to obtain enough protein efficiently in vitro, in addition we also analysed the usage of rare codons in the genes of E2 and CORE. All results have shown that great efforts should be made to improve the expression efficiency of E2 in bacteria or mammalian cells.

Thermodynamic Properties of the Charge density wave Transition in Potasium Blue Brone

Thermodynamic properties of the charge density wave(CDW) transition in potassium blue bronze K 0.3 MoO 3 are investigated by the measurement of specific heat. A second order phase transition is observed at 177.5 K. The specific heat jump, and enthalpy and entropy changes associated with the transition are estimated. The results suggest that the lattice plays an important role in thermodynamics for this compound. Analysis of the data near CDW transition shows that width of critical region is about 6 K and the critical behavior belongs to the universality class of the three dimensional XY model.

Network analysis of screening and regulation of differentially expressed genes in platelets of patients with myocardial infarction based on bioinformatics

Objective:To construct a core miRNA regulatory network in peripheral blood platelets of patients with acute myocardial infarction,,and to explore the role of peripheral blood platelet-related miRNAs in the occurrence and development of acute myocardial infarction.Methods:miRNA and mRNA expression profiling chips were used to screen out differentially expressed miRNA and mRNA.FunRich 3.1.3 software was performed to predict the transcription factors and target genes of differentially expressed miRNA,and then the predicted target genes were intersected with the differentially expressed genes screened by the gene chip.Cytoscape software was applied to construct miRNA-mRNA regulatory network,and we performed KEGG and GO analysis of genes in the regulatory network.Results:A total of 27 differentially expressed miRNAs and 2897 differentially expressed mRNAs were screened through gene expression profiling data.A total of 3563 target genes for differentially expressed miRNAs were predicted,and they were intersected with the differentially expressed mRNAs.After a one-to-one correspondence,there were 503 miRNA-mRNA regulatory relationships.KEGG enrichment and GO analysis of the target genes in the regulatory network showed that these target genes are mainly involved in PI3K-AKT signaling pathway,regulation of actin cytoskeleton,MAPK signaling pathway,human papillomavirus infection,and Ras signaling pathway.GO analysis indicated that the main molecular functions of genes from network included protein macromolecule adaptor activity,molecular adaptor activity,DNA binding transcription repressor activity,etc.Conclusion:We analyzed the miRNA-mRNA regulatory network and the different function in the platelets of acute myocardial infarction and non-infarction populations,and further understood the important role of platelets in the process of acute myocardial infarction,and deepened our understanding of the pathological mechanism of acute myocardial infarction.

Study on early warning index of spatial deformation for high concrete dam

Owing to the deficiency in early warning for high concrete dam,a formula was established to characterize the deformation behavior of high concrete dam as a whole.The early warning index of spatial deformation was calculated by low probability principle on the basis of the deformation entropy formula proposed.The steps were as follows.Firstly,the probability method was utilized to define the degree of order and degree of chaos for each survey point.Secondly,the weight distribution among the survey points was calculated by projection pursuit analysis.Thirdly,the formula of holistic deformation entropy,which can represent the degree of order of high concrete dam,was established on the basis of synergetics and information entropy.Lastly,the early warning index of deformation entropy was computed by low probability method based on series of calculated deformation entropy values.An example showed that the dynamic property of deformation entropy is in accordance with both environmental variables and deflection deformation.Moreover,deformation entropy can be used to improve warning ability and safety management for high concrete dam.

High-resolution urban land-cover mapping and landscape analysis of the 42 major cities in China using ZY-3 satellite images

Detailed and precise urban land-cover maps are crucial for urban-related studies. However, there are limited ways of mapping high-resolution urban land cover over large areas. In this paper, we propose an operational framework to map urban land cover on the basis of Ziyuan-3 satellite images. Based on this framework, we produced the first high-resolution(2 m) urban land-cover map(Hi-ULCM) covering the 42 major cities of China. The overall accuracy of the Hi-ULCM dataset is 88.55%, of which 14 cities have an overall accuracy of over 90%. Most of the producer’s accuracies and user’s accuracies of the land-cover classes exceed 85%. We further conducted a landscape pattern analysis in the 42 cities based on Hi-ULCM. In terms of the comparison between the 42 cities in China, we found that the difference in the land-cover composition of urban areas is related to the climatic characteristics and urbanization levels, e.g., cities with warm climates generally have higher proportions of green spaces. It is also interesting to find that cities with higher urbanization levels are more habitable, in general. From the landscape viewpoint, the geometric complexity of the landscape increases with the urbanization level.Compared with the existing medium-resolution land-cover/use datasets(at a 30-m resolution), HiULCM represents a significant advance in accurately depicting the detailed land-cover footprint within the urban areas of China, and will be of great use for studies of urban ecosystems.

Generalized Hamming weights and equivalences of codes

It is proved that any linear isomorphism between two linear codes which preserves a generalizedHamming weight is a monomial equivalence, which is an extension of a theorem of MacWilliams.

Synergistic Pd/Cu-catalyzed regio-and stereoselective cascade Heck cyclization/borylation/cross-coupling

A cooperative Pd/Cu-catalyzed three-component cross-coupling reaction of alkynes,B_(2)Pin_(2) and alkene-tethered aryl halides is reported.This reaction proceeds under mild conditions and shows broad sub-strate scope,providing a variety of heterocycles containing tetrasubstituted alkenylboronate moieties in synthetically useful yields with excellent chemoselectivity and regioselectivity.This transformation fea-tures the catalytic generation ofβ-borylalkenylcopper intermediates and their use in Pd-catalyzed Heck cyclization/cross-couplings.An enantioselective cascade cyclization/cross-coupling process has also been developed for the synthesis of enantiomerically enriched oxindole bearing a tetrasubstituted alkenyl-boronate moiety.

LOCAL ENERGETICS ON EXPLOSIVE DEVELOPMENT OF EXTRATROPICAL MARINE CYCLONE

Local energetics on explosive development of extratropical marine cyclone was proposed and a diagnosis of the representative cases was performed from local balance,net volume integration budget and vertical distribution using the derived eddy kinetic energy equation and eddy available potential energy equation.The results revealed that three primary scenarios are responsible for the rapid growth of eddy kinetic energy and explosive cyclogenesis,and that a primary explosive development mechanism is the enhanced baroclinic instability by eddy heat transport and eddy diabatic heating,and that the explosive eyclogenesis is essentially a product of the peculiar climatological background bearing strong thermal difference in cold season and its conversion potential.

Expert consensus on COVID-19 vaccination in children

Coronavirus disease 2019(COVID-19)is a public health disaster that has not been encountered for a hundred years.On January 12,2020,the World Health Organization(WHO)confirmed and named the coronavirus which caused unexplained pneumonia as 2019 novel coronavirus(2019-nCoV).Since then,the disease caused by this virus had been named as coronavirus disease 2019(COVID-19).On February 11,2020,the International Committee on Taxonomy of Viruses announced that the English name of the novel coronavirus was severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)[1].At present,SARS-CoV-2 infection is still rampant worldwide.As of September 10,2021,there were about 222 million confirmed cases of COVID-19 and more than 4.5 million deaths worldwide[2].According to the American Centers for Disease Control and Prevention,by July 29,2021,4.19 million pediatric COVID-19 cases had been reported in the United States。