Objective To explore the hemostatic value of performed Microporous polysaccharide hemosph-eres in marginal placenta previa caesarean section,and assess the suitability of the application in primary hospitals. Methods 70 patients with marginal placenta previa were chosen,who regularly antenatal examined in Guangzhou Women and Children's Medical Center from November 2013 to October 2015,and they were randomly divided into two groups:research group(35 patients were performed haemostatics)and control group(35 patients were not performed haemostatics).Results The research group was obviously succeeded in the hemostasis time[(22.8 ±6.2)min vs (11.1 ±5.6)min;t =3.26,P <0.05],local suture[(4.6 ±1.5)times vs (1.9 ±0.7)times;t =3.87,P <0.05], 2h amount of bleeding[(685.4 ±126.7)mL vs (460.1 ±89.3)mL;t =4.66,P <0.05],24h amount of bleeding [(972.0 ±203.5)mL vs (632.3 ±107.1)mL;t =5.19,P <0.05]and failure rate(17.1% vs 2.9%,χ2 =3.96, P <0.05)than those in the control group.There were no significant differences between the two groups in postopera-tive disease rate,puerperal infection rate,the incidence rate of uterine involution,intrauterine adhesions,thrombosis. Conclusion The hemostatic effect is remarkable of Microporous polysaccharide hemospheres used in marginal placenta previa during caesarean section.It works quickly,easily,with little side effects,and is so suitable for promo-tion in primary hospitals.

Objective:To understand the relationship between the RNA shedding time of SARS-CoV-2 infected persons and the single nucleotide mutation of the virus, the population of infected persons, underlying diseases and other factors, so as to provide more clues for the study of SARS-CoV-2 infection dynamics.Methods:The data of epidemiology, clinical manifestations, and underlying diseases of infected persons in a cluster epidemic of COVID-19 in Jiangsu province from July to September 2021 were collected. Nasopharyngeal swab samples of cases were collected, and the whole genome of the virus was sequenced by second-generation sequencing technology. The online analysis platform was used to judge the virus type and analyze the mutation site, and Cox proportional risk model was used to analyze the relationship between the RNA shedding time of SARS-CoV-2 and various research factors.Results:There were 350 persons who finally obtained the whole genome sequence of the virus in this COVID-19 outbreak, of which 60.3% were female, the median age was 49 years old (interquartile range, IQR: 37-65 years old)), and the median time of virus shedding was 33 days ( IQR, 26-44 days). The whole-genome sequencing analysis showed that compared with the Wuhan reference strain sequence, the infected persons’ sequence had 34~41 nucleotide mutation sites, belonging to VOC/Delta variant (B.1.617.2 evolutionary branch), and C346T, C1060T, T2803C, T7513C, A29681C were the main single nucleotide polymorphisms (SNPs) of this epidemic. Cox regression analysis showed that age, underlying disease, clinical classification, vaccination, SNP T2803C and T7513C had an impact on the RNA shedding time of SARS-CoV-2. The adjusted multivariate Cox regression result showed that age [ HR=0.73, 95% CI (0.55, 0.95)] and T7513C [ HR=0.37, 95% CI (0.18, 0.77)] were still the risk factors for the extension of SARS-CoV-2 RNA shedding time. Conclusions:This study analyzed the effects of the individual factors and viral single nucleotide variations on the time of viral RNA shedding. Those who were older, suffered from hypertension, had more severe clinical symptoms, were not vaccinated or incompletely vaccinated, and had T7513C mutation in the infected virus, had a risk of a long RNA shedding time of SARS-CoV-2, which should be given special attention and follow-up after rehabilitation.