SARS-CoV-2侵入因子——ACE2和TMPRSS2在围着床期胚胎和母胎界面存在表达

在全球肆虐的严重急性呼吸综合征冠状病毒2(severe acute respiratory syndrome coronavirus 2,SARS-CoV-2)导致了大量人群感染,血管紧张素转化酶2(angiotensin-converting enzyme 2, ACE2)是SARS-CoV和SARS-CoV-2的受体蛋白。然而是否存在SARS-CoV-2的垂直传播仍颇有争议。为了探讨SARS-CoV-2垂直传播的潜在风险,我们利用已发表的单细胞转录组数据观察了围着床期胚胎和母胎界面上ACE2和TMPRSS2(编码跨膜丝氨酸蛋白酶2)的转录表达情况。结果显示,ACE2和TMPRSS2在第6天(D6)围着床期胚胎的滋养外胚层(trophectoderm, TE)细胞、妊娠第8周的合胞滋养层(syncytiotrophoblast at 8 weeks of gestation, STB8W)细胞以及妊娠第24周的绒毛外滋养层(extravillous trophoblasts at 24 weeks of gestation, EVT24W)细胞中均存在明显的共表达现象,表明这些细胞类群可能易被SARS-CoV-2感染。在这三个细胞类群中,ACE2阳性表达细胞相对于阴性细胞在自噬和免疫相关过程中存在差异。尽管ACE2的表达水平在围着床期胚胎中没有表现出性别偏差,但是其在D6 TE、第6天围着床期胚胎的原始内胚层(D6 primitive endoderm, D6 PE)细胞以及ACE2阳性表达的STB细胞中存在明显的性别差异。这表明围着床期发育第6天以及妊娠期胚胎对SARS-CoV-2的易感性可能存在性别差异。我们的结果揭示了胚胎移植过程中,围着床期以及妊娠期胚胎面临着SARS-CoV-2的潜在感染风险。

Mechanistic insights into the selective hydrogenation of resorcinol to 1,3-cyclohexanedione over Pd/rGO catalyst through DFT calculation

In our previous work, graphene-supported Pd catalyst(Pd/rGO) exhibited higher activity and selectivity for the liquid phase selective hydrogenation of resorcinol to 1,3-cyclohexanedione compared with other catalysts. In the present study, further experimental and theoretical investigations were conducted to reveal the reaction mechanism and the catalytic mechanism of Pd/rGO for resorcinol hydrogenation. The effects of graphene nanosheet and the solvent on the reaction were investigated, and the pathway for resorcinol hydrogenation was proposed supported by density functional theory(DFT) calculations. The results showed that the excellent selectivity of Pd/rGO to 1,3-cyclohexanedione was attributed to the strong π–π and p–π interactions between the graphene nanosheet and the benzene ring as well as hydroxyl in resorcinol molecule, which was in agreement with our previous speculation. In weak polar aprotic solvents, solvation free energy had less impact to the π–π and p–π interactions mentioned above. In strong polar aprotic solvents and polar protic solvents,however, the influence of solvation free energy was much greater, which led to the decrease in the conversion of resorcinol and the selectivity to 1,3-cyclohexanedione.

Single-cell transcriptome analysis of the novel coronavirus (SARS-CoV-2) associated gene ACE2 expression in normal and non-obstructive azoospermia (NOA) human male testes

Being infected by SARS-CoV-2 may cause damage to multiple organs in patients, such as the lung, liver and heart. Angiotensin-converting enzyme 2(ACE2), reported as a SARS-CoV-2 receptor, is also expressed in human male testes. This suggests a potential risk in human male reproductive system. However, the characteristics of ACE2-positive cells and the expression of other SARS-CoV-2 process-related genes are still worthy of further investigation. Here, we performed singlecell RNA seq(scRNA-seq) analysis on 853 male embryo primordial germ cells(PGCs) and 2,854 normal testis cells to assess the effects of the SARS-CoV-2 virus on the male reproductive system from embryonic stage to adulthood. We also collected and constructed the scRNA-seq library on 228 Sertoli cells from three non-obstructive azoospermia(NOA) patients to assess the effects at disease state. We found that ACE2 expressing cells existed in almost all testis cell types and Sertoli cells had highest expression level and positive cells ratio. Moreover, ACE2 was also expressed in human male PGCs. In adulthood, the level of ACE2 expression decreased with the increase of age. We also found that ACE2 positive cells had high expressions of stress response and immune activation-related genes. Interestingly, some potential SARS-CoV-2 process-related genes such as TMPRSS2, BSG, CTSL and CTSB had different expression patterns in the same cell type. Furthermore, ACE2 expression level in NOA donors’ Sertoli cells was significantly decreased. Our work would help to assess the risk of SARS-CoV-2 infection in the male reproductive system.

Hydrogen evolution and electromigration in the corrosion of aluminium metal sheath inside high‐voltage cables

The urgent need for power transmission is the reason for leading research on the safer operation of high‐voltage cables.These high‐voltage cables are emerging as an efficient technology for underground power transmission.However,the electrochemical corrosion of aluminium(Al)metal sheaths in these cables is a common and challenging degradation process.Herein,the corrosion mechanisms and electrochemical analysis are investigated by using scanning electron microscopy(SEM),Fourier transform infrared spectroscopy(FTIR),electrochemical impedance spectroscopy(EIS)and laboratory‐designed electro-chemical characterisation techniques.In the corrosion experiments,the authors evaluated the corrosion rate by measuring the release rate of hydrogen gas and explored the different roles of sodium polyacrylate(NaPA)during the corrosion process.It is found that the complexation reactions between NaPA and Al inhibited corrosion while increased the resistance of the buffer layer.The proposed mechanisms of corrosion in this study can improve the lifespan and sustainability of high‐voltage power transmission.

Morphology evolution and breakdown mechanism of cross-linked polyethylene(XLPE)-silicone rubber(SiR)interface induced by silicone grease diffusion

Silicone grease(SG)is used for lubrication during cable accessory installation and can penetrate into the silicone rubber(SiR),leading to properties deterioration of the SiR.In this study,the effects of SG on the breakdown characteristics of the cross-linked poly-ethylene(XLPE)-SiR interface are investigated.First,the variation of the XLPE-SiR interface breakdown voltage with SG coating time is experimentally explored.The interface breakdown voltage significantly increases after SG is applied,remains stable for coating times of up to approximately 144 h and then rapidly decreases;the minimum interface breakdown voltage is lower than that without the SG coating.Next,the effects of SG on the chemical composition and surface topography of the SiR are examined by infrared spectroscopy and optical profilometry,respectively.The SG penetration does not change the functional groups of the SiR but significantly increases its surface roughness.Finally,the interface electric-field distribution after coating with SG is analysed by finite-element simulation,revealing that the residual SG at the interface distorts the interface electric field after a long coating time.The increase in the SiR surface roughness caused by SG diffusion and the interface electric-field distortion caused by the residual SG together lead to the decrease of the interface breakdown voltage.

Effects of SARS-CoV-2 infection on human reproduction

The worldwide infection of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)impacts human health and life on multiple levels.People infected with SARS-CoV-2 suffer from physical disorders and psychological distress.At present,no direct evidence indicates that SARS-CoV-2 negatively influences human reproduction,and the possibility that gametes and embryos are affected requires further investigation.To evaluate the potential effects of SARS-CoV-2 infection on human reproduction and fetal health,this review summarizes the basic and clinical research of SARS-CoV-2 on reproduction up to date,hoping to offer guidance and advice to people at reproductive age and provide dues for the prevention and treatment of associated diseases.