Abstract Background Spontaneous abortion is a common complication of pregnancy that can lead to adverse physical and psychological outcomes for women. Vitamin D is reported to be associated with reproductive functions, whereas its casual effects on abortion remains unclear. Materials and methods In this study, a two-sample Mendelian randomization (MR) analysis was performed to systematically assess the causal relationships between serum 25 hydroxyvitamin D [25(OH)D] concentration and the risk of spontaneous abortion. GWAS summary data of 25(OH)D were used as exposure, and data of spontaneous abortion was considered as outcome. A retrospective study was additionally conducted to verify the MR results. Results MR estimates showed that a higher 25(OH)D level was potentially associated with decreased risk of spontaneous abortion (IVW, OR = 0.98, 95%CI = 0.90–1.06; MR Egger, OR = 0.94, 95%CI = 0.84–1.05; Weighted median, OR = 0.93, 95%CI = 0.82–1.06; Weighted mode, OR = 0.93, 95%CI = 0.84–1.03), though the P-value was not statistically significant. The retrospective study also produced consistent result of Vitamin D’s protective role to spontaneous abortion. The P-value was very close to statistical significance (P = 0.053). Conclusions This study reports the potential protective role of serum 25(OH)D concentration to spontaneous abortion, suggesting that increased vitamin D levels may decrease the risk of abortion. Further larger prospective studies and/or even randomized controlled trials are needed to confirm causal relationship between vitamin D and abortion.

Abstract Background: Abortion was defined as loss at a gestational age less than 28 weeks. Vitamin D is reported to be associated with reproductive functions, whereas its casual effects on abortion remains unclear. In this study, a two-sample Mendelian randomization (MR) analysis was performed to systematically assess the causal relationships between serum 25 hydroxyvitamin D concentration and the risk of abortion. Results: GWAS summary data of vitamin D was used as exposure, and data of missed abortion and spontaneous abortion was considered as outcome. A retrospective study was also conducted to verify the associations identified from MR study. MR estimates showed that a higher Vitamin D level was associated with decreased risk of both missed abortion and spontaneous abortion. However, the P value was not significant. We then conducted a retrospective study, and observed the consistent result of Vitamin D’s protective role to abortion. The value was very close to statistical significance (P=0.0527). Conclusions: This study reports the potential protective role of serum 25 hydroxyvitamin D concentration to abortion, that is, higher Vitamin D levels can decrease risk of abortion. Further larger retrospective study is needed to confirm this association.

溶解氧(DO)是调控地表水水质、维持水生生态系统健康的关键因子.当前我国许多河流因有机污染而出现缺氧现象,因此,曝气就成为水体治理和生态修复的一种常用手段.光照、温度等环境因子的昼夜变化能够显著影响水体的自然复氧过程,曝气与日间和夜间的自然复氧过程相叠加时可能产生不同的耦合效果.本研究以典型平原河网水系某河流为研究对象,分别在日间曝气、夜间曝气模式下,对河流表、底层溶解氧等水质指标进行多日连续监测,以研究不同曝气节律对河流的复氧效果.结果显示,日间曝气对夏季河流水体补氧贡献不显著,且夜间停止曝气后水体出现了显著的缺氧状况.夜间曝气对水体的补氧效果较好,结合昼间水体的自然复氧,能够全日避免水体出现缺氧情况.本研究表明,在了解水体自然复氧能力的基础上合理地结合夜间曝气,将可能获得更加高效的曝气方案.

本文以浙江某校内河道某河段作为试验区,在种植植物的基质区(A)和无植物的基质区(B)分别于水深20 cm和50 cm处取样,分析2处不同试验体系下人工基质上生物膜的微生物群落结构,采用高通量测序技术,分析微生物的群落组成、丰度和多样性.结果表明,变形菌门、浮霉菌门、拟杆菌门是2组基质上的优势门.在种植植物区的物种丰度为A20>A50,无植物区的B20、B50处变形菌门、浮霉菌门的物种丰度差异不明显;不同采样位点微生物的OTU组成存在明显差异,Shannon及Simpson指数显示,生物多样性差异和均匀度没有显著变化.

生物膜的存在可改变原有基质对有机污染物的吸附及降解特征,对污染物在水体中的迁移转化起着决定性作用,其酶活性的大小从一定程度上指示着水体自净能力的高低.为了探究种植植物是否会对生态护坡基质上的生物膜酶活产生影响,本文对同一河段中种植再力花的新型人工基质M和不种植再力花的新型人工基质N上生物膜磷酸酶、脲酶和脱氢酶活性及微生物总量进行测定.研究结果显示,微生物量总体上表现为基质M高于基质N,且总体上冬季生物量最大,春季最少;四个季节的磷酸酶、脲酶、脱氢酶活性均是基质M高于基质N;植物对磷酸酶和脲酶活性的促进作用在夏季较为显著,对脱氢酶活性的促进作用在秋季较为显著.

曝气是水体复氧和生态修复的一种常用方法.本研究以秋、 冬季节的典型平原河网水系河流为研究对象,在常用的昼间曝气模式下,对河流表、底层溶解氧等水质指标进行多日连续监测,以研究昼间曝气对河流的复氧效果.结果显示,在秋季,昼间曝气对河流表、底层水体有一定的复氧作用,但夜间曝气停止后溶解氧消耗较快,水体溶解氧表现出明显的昼夜波动变化,至清晨出现严重缺氧.冬季,昼间曝气后河流表、底层水体溶解氧含量均有所提高,且夜间溶解氧含量下降较少,曝气效果较好.研究结果可为今后设计更加高效的曝气方案提供依据.