High-purity ultrafine W or WC powder was prepared via a two-step process composed of the carbothermic pre-reduction of WO2.9 and the following deep reduction with H2 or carbonization with CH4+H2 mixed gases. The effec...High-purity ultrafine W or WC powder was prepared via a two-step process composed of the carbothermic pre-reduction of WO2.9 and the following deep reduction with H2 or carbonization with CH4+H2 mixed gases. The effects of C/WO2.9 molar ratio and temperature on phase composition, morphology, particle size, and impurity content of products were investigated. The results revealed that when the C/WO2.9ratio was in the range from 2.1:1 to 2.5:1, the carbothermic pre-reduction products consisted of W and a small amount of WO2. With changing C/WO2.9 ratio from 2.1:1 to 2.5:1, the particle sizes were gradually decreased. In order to prepare ultrafine W or WC powder, a relatively high C/WO2.9 ratio and a lower reaction temperature at this stage were preferred. After the second reaction, the final products of ultrafine W and WC powders with a high purity could be obtained, respectively.展开更多
The Omicron variant of the severe acute respiratory syndrome coronavirus 2(SARS‑CoV‑2)infected a substantial proportion of Chinese population,and understanding the factors underlying the severity of the disease and fa...The Omicron variant of the severe acute respiratory syndrome coronavirus 2(SARS‑CoV‑2)infected a substantial proportion of Chinese population,and understanding the factors underlying the severity of the disease and fatality is valuable for future prevention and clinical treatment.We recruited 64 patients with invasive ventilation for COVID-19 and performed metatranscriptomic sequencing to profile host transcriptomic profiles,plus viral,bacterial,and fungal content,as well as virulence factors and examined their relationships to 28-day mortality were examined.In addition,the bronchoalveolar lavage fluid(BALF)samples from invasive ventilated hospital/community-acquired pneumonia patients(HAP/CAP)sampled in 2019 were included for comparison.Genomic analysis revealed that all Omicron strains belong to BA.5 and BF.7 sub-lineages,with no difference in 28-day mortality between them.Compared to HAP/CAP cohort,invasive ventilated COVID-19 patients have distinct host transcriptomic and microbial signatures in the lower respiratory tract;and in the COVID-19 non-survivors,we found significantly lower gene expressions in pathways related viral processes and positive regulation of protein localization to plasma membrane,higher abundance of opportunistic pathogens including bacterial Alloprevotella,Caulobacter,Escherichia-Shigella,Ralstonia and fungal Aspergillus sydowii and Penicillium rubens.Correlational analysis further revealed significant associations between host immune responses and microbial compositions,besides synergy within viral,bacterial,and fungal pathogens.Our study presents the relationships of lower respiratory tract microbiome and transcriptome in invasive ventilated COVID-19 patients,providing the basis for future clinical treatment and reduction of fatality.展开更多
基金Project(51725401)supported by the National Natural Science Foundation of China。
文摘High-purity ultrafine W or WC powder was prepared via a two-step process composed of the carbothermic pre-reduction of WO2.9 and the following deep reduction with H2 or carbonization with CH4+H2 mixed gases. The effects of C/WO2.9 molar ratio and temperature on phase composition, morphology, particle size, and impurity content of products were investigated. The results revealed that when the C/WO2.9ratio was in the range from 2.1:1 to 2.5:1, the carbothermic pre-reduction products consisted of W and a small amount of WO2. With changing C/WO2.9 ratio from 2.1:1 to 2.5:1, the particle sizes were gradually decreased. In order to prepare ultrafine W or WC powder, a relatively high C/WO2.9 ratio and a lower reaction temperature at this stage were preferred. After the second reaction, the final products of ultrafine W and WC powders with a high purity could be obtained, respectively.
基金funded by the National Key Research and Development Program of China(2022YFC2303200)Capital Development Key Grant of China(2022-1-5091).
文摘The Omicron variant of the severe acute respiratory syndrome coronavirus 2(SARS‑CoV‑2)infected a substantial proportion of Chinese population,and understanding the factors underlying the severity of the disease and fatality is valuable for future prevention and clinical treatment.We recruited 64 patients with invasive ventilation for COVID-19 and performed metatranscriptomic sequencing to profile host transcriptomic profiles,plus viral,bacterial,and fungal content,as well as virulence factors and examined their relationships to 28-day mortality were examined.In addition,the bronchoalveolar lavage fluid(BALF)samples from invasive ventilated hospital/community-acquired pneumonia patients(HAP/CAP)sampled in 2019 were included for comparison.Genomic analysis revealed that all Omicron strains belong to BA.5 and BF.7 sub-lineages,with no difference in 28-day mortality between them.Compared to HAP/CAP cohort,invasive ventilated COVID-19 patients have distinct host transcriptomic and microbial signatures in the lower respiratory tract;and in the COVID-19 non-survivors,we found significantly lower gene expressions in pathways related viral processes and positive regulation of protein localization to plasma membrane,higher abundance of opportunistic pathogens including bacterial Alloprevotella,Caulobacter,Escherichia-Shigella,Ralstonia and fungal Aspergillus sydowii and Penicillium rubens.Correlational analysis further revealed significant associations between host immune responses and microbial compositions,besides synergy within viral,bacterial,and fungal pathogens.Our study presents the relationships of lower respiratory tract microbiome and transcriptome in invasive ventilated COVID-19 patients,providing the basis for future clinical treatment and reduction of fatality.
