Research on Cold Chain Logistics Service Quality Evaluation Considering Product Freshness under Community Group Buying

In 2019, The outbreak of Corona Virus Disease 2019 (named COVID-19) has caused great changes in the living habits of residents, and the community group buying model has re-emerged. Under the background of community group buying mode, combined with the characteristics of fresh products, and based on the SEVRQUAL model and the national standard of "Logistics Enterprise Cold Chain Service Requirements and Capability Evaluation Indicators", an evaluation index system of cold chain logistics service quality for community group purchase of fresh products with 5 dimensions and 29 indicators is constructed from the perspective of users. Then a 5-level Likert scale was used to design relevant questionnaires, and Xingsheng Youxuan and Meituan Youxuan were used as empirical cases for sample research. Combined collected sample data, the validity and rationality of the index system were tested through reliability, validity testing and factor analysis. The data analysis also shows the problems and influencing factors of Xingsheng Youxuan and Meituan Youxuan in terms of fresh food cold chain logistics service quality, and further suggestions for the development of cold chain logistics services considering product freshness under community group buying is also provided. © 2022 ACM.

Research on cold chain logistics development strategy in the post-epidemic era of China

In 2019, the outbreak of Corona Virus Disease 2019 (named COVID-19) poses new challenges to cold chain logistics in China. After the epidemic, the development of cold chain logistics is worth pondering. In this article, based on the development status of cold chain logistics in China after the epidemic, it analyzes the problems in the development of cold chain logistics, and combines the background of the post-epidemic era, formulates the corresponding development strategies, which aims to provide a reference for the development of cold chain logistics in China in the post-epidemic era. © 2021 ACM. Copyright held by the owner/author(s). Publication rights licensed to ACM.

Clinical characteristics of patients with COVID-19 combined with cardiovascular disease

Objective: To retrospectively analyze the clinical characteristics of coronavirus disease 2019 (COVID-19) and the impact of cardiovascular disease (CVD) on the clinical manifestations of COVID-19. Methods: A total of 128 patients diagnosed with COVID-19 in Renmin Hospital of Wuhan University from February 1 to February 29, 2020 were divided into CVD group (n=62) and non-CVD group (n=66). The general data, admission symptoms and laboratory examination results including blood routine, immunity, heart, liver and kidney function were obtained and statistically analyzed by SPSS 22.0 statistical software. The differences of various indexes between CVD group and non-CVD group were compared. Results: There was no significant difference in gender between CVD group and non-CVD group(P>0.05).The average age of CVD group was higher than that of non-CVD group (P<0.001). The proportion of fever and cough, severe and critical patients was higher than that respectively of non-CVD group (all P<0.05). There was no significant difference in the incidence of fatigue, dyspnea, and asymptomatic between the two groups (all P>0.05). The average levels of eukocyte count, neutrophil ratio, neutrophil count, monocyte count, and C-reactive protein in CVD group were higher than those in non-CVD group (all P<0.05), while the average lymphocyte proportion in CVD group was lower than that in non-CVD group (P<0.05). There was no significant difference in lymphocyte count and platelet count between the two groups (both P>0.05). The average LDH, myohemoglobin, CK-MB, NT-proBNP, TBIL, and Urea in CVD group were higher than those in non-CVD group (all P<0.05), but there was no significant difference in ALT, AST, and Cr between the two groups (all P>0.05). Conclusion: Compared with non-CVD patients with COVID-19, CVD patients with COVID-19 are older, have more obvious symptoms, with a higher risksin heart, liver, and kidney injury, but the mechanism is not clear yet. © 2021, Editorial Board of Medical Journal of Wuhan University. All right reserved.

Rapid generation of potent antibodies by autonomous hypermutation in yeast.

The predominant approach for antibody generation remains animal immunization, which can yield exceptionally selective and potent antibody clones owing to the powerful evolutionary process of somatic hypermutation. However, animal immunization is inherently slow, not always accessible and poorly compatible with many antigens. Here, we describe 'autonomous hypermutation yeast surface display' (AHEAD), a synthetic recombinant antibody generation technology that imitates somatic hypermutation inside engineered yeast. By encoding antibody fragments on an error-prone orthogonal DNA replication system, surface-displayed antibody repertoires continuously mutate through simple cycles of yeast culturing and enrichment for antigen binding to produce high-affinity clones in as little as two weeks. We applied AHEAD to generate potent nanobodies against the SARS-CoV-2 S glycoprotein, a G-protein-coupled receptor and other targets, offering a template for streamlined antibody generation at large.

Unification of the M/ORF3-related proteins points to a diversified role for ion conductance in pathogenesis of coronaviruses and other nidoviruses (preprint)

The new coronavirus, SARS-CoV-2, responsible for the COVID-19 pandemic has emphasized the need for a better understanding of the evolution of virus-host conflicts. ORF3a in both SARS-CoV-1 and SARS-CoV-2 are ion channels (viroporins) and involved in virion assembly and membrane budding. Using sensitive profile-based homology detection methods, we unify the SARS-CoV ORF3a family with several families of viral proteins, including ORF5 from MERS-CoVs, proteins from beta-CoVs (ORF3c), alpha-CoVs (ORF3b), most importantly, the Matrix (M) proteins from CoVs, and more distant homologs from other nidoviruses. By sequence analysis and structural modeling, we show that these viral families utilize specific conserved polar residues to constitute an ion-conducting pore in the membrane. We reconstruct the evolutionary history of these families, objectively establish the common origin of the M proteins of CoVs and Toroviruses. We show that the divergent ORF3a/ORF3b/ORF5 families represent a duplication stemming from the M protein in alpha- and beta-CoVs. By phyletic profiling of major structural components of primary nidoviruses, we present a model for their role in virion assembly of CoVs, ToroVs and Arteriviruses. The unification of diverse M/ORF3 ion channel families in a wide range of nidoviruses, especially the typical M protein in CoVs, reveal a conserved, previously under-appreciated role of ion channels in virion assembly, membrane fusion and budding. We show that the M and ORF3 are under differential evolutionary pressures; in contrast to the slow evolution of M as core structural component, the CoV-ORF3 clade is under selection for diversification, which indicates it is likely at the interface with host molecules and/or immune attack.

Rapid generation of potent antibodies by autonomous hypermutation in yeast (preprint)

The predominant approach for antibody generation remains animal immunization, which can yield exceptionally selective and potent antibody clones owing to the powerful evolutionary process of somatic hypermutation. However, animal immunization is inherently slow, has poor compatibility with certain antigens (e.g., integral membrane proteins), and suffers from self-tolerance and immunodominance, which limit the functional spectrum of antibodies that can be obtained. Here, we describe Autonomous Hypermutation yEast surfAce Display (AHEAD), a synthetic recombinant antibody generation technology that imitates somatic hypermutation inside engineered yeast. In AHEAD, antibody fragments are encoded on an error-prone orthogonal DNA replication system, resulting in Saccharomyces cerevisiae populations that continuously mutate surface-displayed antibody repertoires. Simple cycles of yeast culturing and enrichment for antigen binding drive the evolution of high-affinity antibody clones in a readily parallelizable process that takes as little as 2 weeks. We applied AHEAD to generate nanobodies against the SARS-CoV-2 S glycoprotein, a GPCR, and other targets. The SARS-CoV-2 nanobodies, concurrently evolved from an open-source naive nanobody library in 8 independent experiments, reached subnanomolar affinities through the sequential fixation of multiple mutations over 3-8 AHEAD cycles that saw ~580-fold and ~925-fold improvements in binding affinities and pseudovirus neutralization potencies, respectively. These experiments highlight the defining speed, parallelizability, and effectiveness of AHEAD and provide a template for streamlined antibody generation at large with salient utility in rapid response to current and future viral outbreaks.