1 BackgroundThe outbreak of novel coronavirus pneumonia (NCP) caused by

This paper investigates the influence of air temperature and relative humidity on the transmission of COVID-19. After estimating the serial interval of COVID-19 from 105 hand-collected pairs of the virus carrier and the infected, we calculate the daily effective reproductive number, R, for each of all 100 Chinese cities with more than 40 cases. Using the daily R values from January 21 to 23, 2020 as proxies of nonintervened transmission intensity, we find, under a linear regression framework, high temperature and high humidity significantly reduce the transmission of COVID-19, respectively. One-degree Celsius increase in temperature and one percent increase in relative humidity lower R by 0.0225 and 0.0158, respectively. This result is consistent with the fact that the high temperature and high humidity reduce the transmission of influenza and SARS. It indicates that the arrival of summer and rainy season in the northern hemisphere can effectively reduce the transmission of the COVID-19. We also developed a website to provide R of major cities around the world according to their daily temperature and relative humidity:

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Upland cotton is the most important natural-fiber crop. The genomic variation of diverse germplasms and alleles underpinning fiber quality and yield should be extensively explored. Here, we resequenced a core collection comprising 419 accessions with 6.55-fold coverage depth and identified approximately 3.66 million SNPs for evaluating the genomic variation. We performed phenotyping across 12 environments and conducted genome-wide association study of 13 fiber-related traits. 7,383 unique SNPs were significantly associated with these traits and were located within or near 4,820 genes; more associated loci were detected for fiber quality than fiber yield, and more fiber genes were detected in the D than the A subgenome. Several previously undescribed causal genes for days to flowering, fiber length, and fiber strength were identified. Phenotypic selection for these traits increased the frequency of elite alleles during domestication and breeding. These results provide targets for molecular selection and genetic manipulation in cotton improvement.

In this open-label randomized clinical trial, HLA-identical sibling-matched hematopoietic stem cells (HSC) were transplanted (non-MSCs group, n ¼ 15) or cotransplanted with mesenchymal stem cells (MSCs) (MSCs group, n ¼ 10) in hematologic malignancy patients. The median number of MSCs infused was 3.4 Â 10 5 kg À1 (range, 0.3-15.3 Â 10 5 kg À1 ). MSCs infusions were well tolerated. The median time to neutrophil engraftment (absolute neutrophil count 40.5 Â 10 9 l À1 ) was 16 days for MSCs group and 15 days for non-MSCs group. The median time to platelet engraftment (platelet count 450 Â 10 9 l À1 ) was 30 and 27 days, respectively. Grades II-IV acute graft-versus-host disease (GVHD) was observed respectively, in one (11.1%) and eight (53.3%) evaluable patients. Chronic GVHD was found in one (14.3%) and four (28.6%) evaluable patients. The number of patients who relapsed were six (60.0%) and three (20.0%), and the 3-year disease-free survivals were 30.0 and 66.7%, respectively. Thus cotransplantation of MSCs and HSCs may prevent GVHD, but the relapse rate is obviously higher than the control group. We conclude that use of MSCs must be handled with extreme caution before a large-scale clinical trial is performed.

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The global pandemic of Coronavirus Disease 2019 (COVID-19) is now ongoing. Rapid and accurate detection of the causative virus SARS-CoV-2 is vital for the treatment and control of COVID-19. In this study, the comparative sensitivity of different respiratory specimens were retrospectively analyzed using 3552 clinical samples from 410 Guangdong CDC (Center for Disease Control and Prevention) confirmed COVID-19 patients. Except for BALF, the sputum possessed the highest positive rate (73.4%∼87.5%), followed by nasal swabs (53.1%∼85.3%) for both severe and mild cases during the first 14 days after illness onset (d.a.o). Viral RNA could be detected in all BALF from the severe group collected as early as 4 days after illness onset (d.a.o) and lasted up to 46 d.a.o., while none of BALF samples from mild group. Moreover, although viral RNA was negative in the upper respiratory samples, it was also positive in BALF samples in most cases from severe group during treatment. Despite of typical ground-glass opacity observed via computed tomographic (CT) scans, no viral RNA was detected in the first 3 or all upper respiratory tract specimens from some COVID-19 patients. In conclusion, sputum is most sensitive for routine laboratory diagnosis of COVID-19, followed by nasal swabs. Detection of viral RNAs in BLAF improves diagnostic accuracy in severe COVID-19 patients.

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