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1 Medicalxpress,1月13日,Preliminary research suggests SARS-CoV-2 virus less infectious within five minutes of exposure to air 2022-01-25

In astudy that has not yet been peer-reviewed or accepted for publication,researchers at Bristol University in the U.K.have found evidence that suggests the SARS-CoV-2 virus becomes less infectious within five minutes of exposure to air.The team has published apaper on the pre-print server MedRxiv describing tests designed to simulate the behavior of the virus after it is transmitted into the air by an infected person. Since the pandemic first began,health care officials have been asking people around the world to wear amask.The main purpose of such masks for non-health-care workers is to slow the speed with which the virus is transmitted into the air as aperson exhales,sneezes or coughs.The thinking has been that wearing amask helps to protect those around an infected person.In this new effort,the researchers found evidence that suggests the virus,once transmitted into the air,has only five minutes until it starts losing its ability to infect other people.If the finding proves to be accurate,wearing amask becomes even more important.Preventing the virus from sailing across an open space when it only has five minutes to infect someone would reduce its transmissibility drastically. The researchers chose asimulation method that has not been used by other researchers—instead of using Goldberg drums,they created an apparatus that generates and levitates viruses between electric rings.The virus samples are thus held in astate in which their infectiousness could be measured. The researchers found that its transmissibility began dropping within five minutes of exposure to the air.A closer look showed that this is because it begins to dry out and suffers alack of carbon dioxide.They found that after 20 minutes,the transmissibility of the virus was reduced by 90 percent.They also found that more humid air slowed the loss of transmissibility,and that temperature had no impact. At this time,it is not yet clear how well the method matches with conditions in anatural environment.Also,the new method does not take into account ventilation,room size or the viral load of the infected person.And finally,it is still not known what level of transmissibility the virus must have in order to infect people. 查看详细>>

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2 Medicalxpress,1月13日,Maternal COVID-19 infection increases risks of preterm birth, low birth weight and stillbirth 2022-01-25

People who contracted COVID-19 while pregnant were more likely to have poor birth outcomes including preterm birth,small for gestational age,low birth weight,and stillbirth.The poor outcomes of preterm birth and stillbirth were observed primarily with those infected with SARS-CoV-2 during the first or second trimester,whereas increased rates of small for gestational age were driven largely by third trimester infection. An Institute for Systems Biology-led study examined the electronic health records of more than 18,000 people with SARS-CoV-2 tests during pregnancy.Researchers compared outcomes of unvaccinated people with apositive test during pregnancy—882 in total—to those who tested negative. "We found that SARS-CoV-2 infection indicated increased rates of preterm delivery and stillbirth,largely driven by first and second trimester infections,"said Samantha Piekos,Ph.D.,first author of the study.She added:"The single greatest predictor of gestational age at delivery is gestational age at infection,with earlier age at infection associated with earlier age at delivery." The study results were used by the Centers for Disease Control and Prevention to support the use of booster shots. 查看详细>>

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3 Medicalxpress,1月12日,Researchers use artificial intelligence to guide the search for the next SARS-like virus 2022-01-25

Vaccination offers long-lasting protection from the worst outcomes of COVID-19,according to anew study by the University of North Carolina at Chapel Hill. The emergence of the delta and omicron variants has raised questions about whether breakthrough infections are caused by waning immunity or by the more transmissible variants. Results of the study published in the New England Journal of Medicine suggest that declining immunity is responsible for breakthrough infections,but vaccines maintained protection from hospitalization and severe disease nine months after getting the first shot. "The primary takeaway message from our study is that unvaccinated people should get vaccinated right away,"said lead study author Danyu Lin,Ph.D.,Dennis Gillings Distinguished Professor of Biostatistics at the UNC Gillings School of Global Public Health."The results of our study also underscore the importance of booster shots,especially for older adults." The study,which is acollaboration between the UNC-Chapel Hill and the North Carolina Department of Health and Human Services,examined data on COVID-19 vaccination history and health outcomes for 10.6 million North Carolina residents between December 2020 and September 2021. 查看详细>>

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4 1月12日_研究人员发现可抑制SARS-CoV-2复制的化合物 2022-01-25

Medicalxpress网站1月12日消息,芝加哥大学普利兹克分子工程学院的研究人员使用先进的计算模拟来分析了一种对SARS-CoV-2及其它冠状病毒复制至关重要的蛋白质。这种蛋白质被称为Nsp13,属于一类称为解旋酶的酶,它们在病毒的复制过程中发挥作用。研究人员还发现了三种可与Nsp13结合并抑制病毒复制的不同化合物,这些抑制剂可以作为设计针对螺旋酶的药物以治疗COVID-19的起点。相关研究发表在期刊《科学进展》上。 研究人员使用先进的计算模拟分析了允许SARS-CoV-2复制或感染细胞的蛋白质。研究人员分析了蛋白质Nsp13,它将双链DNA解开成两条单链,这是复制的关键步骤。此前,研究人员知道Nsp13执行了这一过程,但并不了解该过程的复杂动力学。此次模拟揭示了蛋白质内的多个结构域如何相互通信并相互协同,进而使双链DNA解开。研究人员还发现,当外部分子与蛋白质的某些位点结合时,就会破坏这个通信网络。这意味着蛋白质不能再有效地解开DNA双链,这使得病毒复制变得更加困难。研究人员选择了三种可抑制Nsp13的化合物进行了模拟测试:bananin、SSYA10-001和chromone-4c。结果发现,这三者似乎都通过与某些位点结合并破坏蛋白质的网络而有效地破坏Nsp13蛋白。 查看详细>>

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