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 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.展开更多
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 mal...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.展开更多
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 transmi...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.展开更多
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 brea...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.展开更多
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 d...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.展开更多
基金Supported by the National Natural Science Foundation of China(21476211)the Natural Science Foundation of Zhejiang Province(LY16B060004,LY18B060016)
文摘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.
基金funded by Beijing Municipal Science & Technology Commission (Z191100006619075)the National Natural Science Foundation of China (81521002 and 81730038)。
文摘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.
文摘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.
基金Basic Applied Study of Sichuan Province,Grant/Award Number:2021YJ0538National Natural Science Foundation of China,Grant/Award Numbers:NSFC 51877142,NSFC 52107158。
文摘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.
基金the National Key Research and Development Program(2019YFA0801400)the National Natural Science Foundation of China(81730038).
文摘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.