The structural integrity of the sperm flagellum is essential for proper sperm function.Flagellar defects can result in male infertility,yet the precise mechanisms underlying this relationship are not fully understood....The structural integrity of the sperm flagellum is essential for proper sperm function.Flagellar defects can result in male infertility,yet the precise mechanisms underlying this relationship are not fully understood.CCDC181,a coiled-coil domain-containing protein,is known to localize on sperm flagella and at the basal regions of motile cilia.Despite this knowledge,the specific functions of CCDC181 in flagellum biogenesis remain unclear.In this study,Ccdc181 knockout mice were generated.The absence of CCDC181 led to defective sperm head shaping and flagellum formation.Furthermore,the Ccdc181 knockout mice exhibited extremely low sperm counts,grossly aberrant sperm morphologies,markedly diminished sperm motility,and typical multiple morphological abnormalities of the flagella(MMAF).Additionally,an interaction between CCDC181 and the MMAF-related protein LRRC46 was identified,with CCDC181 regulating the localization of LRRC46 within sperm flagella.These findings suggest that CCDC181 plays a crucial role in both manchette formation and sperm flagellum biogenesis.展开更多
When the induction motor is fed from the PWM VSI inverter, with and without torque enhancing function, the variations of the starting torque and the starting current versus the starting frequency are analyzed, base...When the induction motor is fed from the PWM VSI inverter, with and without torque enhancing function, the variations of the starting torque and the starting current versus the starting frequency are analyzed, based on the steady state equivalent circuit of the induction motor.The corresponding expressions are derived, and the corresponding curves are also drawn, from which the initial starting frequency range can be determined properly and easily. The initial starting frequency range is the common range, in which the starting torque should be high enough and the starting current low enough.Some other useful formulas are also derived.These results are significant for electrical drive designers to make the starting schemes. The effects of the increase of the stator and the rotor resistances on the starting torque and the initial starting frequency range are also discussed, which is caused by the skin effects of the high order harmonics present in the PWM inverter output voltage.展开更多
Ternary Sn-Sb-Cu alloy nanoparticles were successfully synthesized via co-reduction of metal chlorides in aqueous alkaline solution.The results of the transmission electron microscopy(TEM)show that the as prepared Sn-...Ternary Sn-Sb-Cu alloy nanoparticles were successfully synthesized via co-reduction of metal chlorides in aqueous alkaline solution.The results of the transmission electron microscopy(TEM)show that the as prepared Sn-Sb-Cu nanoparticles have a specific hollow structure with a uniform particle size of 10-20 nm.As there are not any hard templates in the synthesis system,a galvanic displacement reaction mechanism is proposed to account for the formation of the hollow nanostructures.When the alloy powders are used as anode materials for lithium-ion batteries,they exhibit relatively high electrochemical capacity and good cyclic retention.The good electrochemical performance can be attributed to the inactive Cu species.During electrochemical reactions,the inactive copper phase in the hollow structure serves as a soft and ductile matrix,which alleviates the mechanical stresses caused by the severe volume change during lithium insertion and extraction.With their high reversible capacities,the Sn-Sb-Cu alloys are a promising candidate as the anode material of rechargeable lithium-ion batteries.展开更多
A new hot-dip galvanizing method was employed on hot-rolled low carbon steel.The effects of Al contents on microstructure,micro-hardness and corrosion resistance of Zn-Al alloy coatings were systematically investigate...A new hot-dip galvanizing method was employed on hot-rolled low carbon steel.The effects of Al contents on microstructure,micro-hardness and corrosion resistance of Zn-Al alloy coatings were systematically investigated.Phase composition,microstructure and element distribution in Zn-Al alloy coatings were analyzed using X-ray diffraction(XRD)and electron probe micro analysis(EPMA),respectively.It is found that Al content(0.6-6.0 wt.%)in galvanizing zinc affects surface quality and adhesion between coatings and matrix in the newly developed method.In addition,with increasing Al content,micro-hardness significantly increased due to the increase in Zn-Al eutectoid phases.Potentiodynamic polarization and electrochemical impedance spectroscopy(EIS)also revealed that increase in Al plays a noticeable role in improving the corrosion resistance of Zn-Al alloy coatings.展开更多
LiFePOa composites were prepared by solid state reactions at different temperatures and time. The crystalline structure and morphology of the composites were analyzed by X-ray diffraction (XRD) and scanning electron...LiFePOa composites were prepared by solid state reactions at different temperatures and time. The crystalline structure and morphology of the composites were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM), while X-ray absorption spectroscopy (XAS) was employed to characterize the crystallinity. Experimental results show that the electrochemical properties do not monotonously get better with the decrease of particle size and the traditional long reaction time is needless. Moreover, XAS is an effective technique to discover the change in crystallinity.展开更多
Objective:To investigate the mechanism by which total alkaloids of Sophora alopecuroides(TASA)and matrine(MT)impair biofilm to increase the susceptibility of Staphylococcus epidermidis(S.epidermidis)to ciprofloxacin.M...Objective:To investigate the mechanism by which total alkaloids of Sophora alopecuroides(TASA)and matrine(MT)impair biofilm to increase the susceptibility of Staphylococcus epidermidis(S.epidermidis)to ciprofloxacin.Methods:The minimum biofilm inhibitory concentration(mBIC)was determined using a 2-fold dilution method.Structure of biofilm of S.epidermidis was examined by Confocal Laser Scanning Microscope(CLSM).The cellular reactive oxygen species(ROS)was determined using a DCFH-DA assay.The key factors related to the regulation of ROS were accessed using respective kits.Results:TASA and MT were more beneficial to impair biofilm of S.epidermidis than ciprofloxacin(CIP)(P<0.05).TASA and MT were not easily developed resistance to biofilm-producing S.epidermidis.The mBIC of CIP decreased by 2-6-fold following the treatment of sub-biofilm inhibitory concentration(sub-BIC)TASA and MT,whereas the mBIC of CIP increased by 2-fold following a treatment of sub-BIC CIP from the first to sixth generations.TASA and MT can improve the production of ROS in biofilmproducing S.epidermidis.The ROS content was decreased 23%-33%following the treatment of submBIC CIP,whereas ROS content increased 7%-24%following treatment with TASA+CIP and MT+CIP combination from the first to sixth generations.Nitric oxide(NO)as a ROS,which was consistent with the previously confirmed relationship between ROS and drug resistance.Related regulatory factorssuperoxide dismutase(SOD)and glutathione peroxidase(GSH)could synergistically maintain the redox balance in vivo.Conclusion:TASA and MT enhanced reactive oxygen species to restore the susceptibility of S.epidermidis to ciprofloxacin.展开更多
Ni-rich cathode material is one of the most promising materials for Li-ion batteries in electric vehicles.However,fading capacity,poor cyclic stability and high p H value are still major challenges,which suppress its ...Ni-rich cathode material is one of the most promising materials for Li-ion batteries in electric vehicles.However,fading capacity,poor cyclic stability and high p H value are still major challenges,which suppress its practical application.In this study,spherical LiNi_(0.)9Co_(0.08)Al_(0.02)O_(2)powders with 0.4 wt%TiO_(2)coating layer were prepared by impregnation-hydrolysis method.Scanning electron microscopy(SEM),high-resolution transmission electron microscopy(HRTEM)and X-ray diffraction(XRD)results show that TiO_(2)is uniformly coated on the surface of LiNi_(0.)9Co_(0.08)Al_(0.02)O_(2)particle and slightly embedded into LiNi_(0.)9Co_(0.08)Al_(0.02)O_(2)particles.After 100 cycles at 2.0 C,0.4 wt%TiO_(2)-coated LiNi_(0.)9Co_(0.08)Al_(0.02)O_(2)electrode delivers much higher discharge capacity retention(77.0%)than the pristine LiNi_(0.)9Co_(0.08)Al_(0.02)O_(2)electrode(63.3%).The excellent cycling performance of 0.4 wt%Ti O_(2)-coated LiNi_(0.)9Co_(0.08)Al_(0.02)O_(2)electrode at a high discharge ratio is due to a TiO_(2)coating layer which can effectively reduce the direct contact between cathode material and electrolyte,suppress the oxidation of electrolyte,improve electrical conductivity of the electrode and increase the stability of the structure.展开更多
The effect of Sn on corrosion behavior of ferritic stainless steels in 20mass% H2SO4 was investigated by alternating current and direct current electrochemical methods and gravimetric tests at 25 ℃.The results show t...The effect of Sn on corrosion behavior of ferritic stainless steels in 20mass% H2SO4 was investigated by alternating current and direct current electrochemical methods and gravimetric tests at 25 ℃.The results show that Sn can effectively improve general corrosion resistance of ferritic stainless steels in H2SO4,mainly due to highly raised hydrogen evolution overpotential which is in favour of strong suppression of hydrogen evolution reaction,and inhibitive effect of dissolved Sn^2+ on elementary anodic reactions.With increasing Sn content,the better corrosion resistance can be reached.The Electrochemical Impedance Spectroscopy(EIS)includes four time constants and can be perfectly fitted by equivalent circuit:Rs(CdlRct)(QadsRads(RL1(L1(RL2L2)))).展开更多
The characterization of corrosion products formed on a high performance offshore platform steel in the en- vironment containing chloride ions has been investigated by scanning electron microscopy (SEM), X ray diffra...The characterization of corrosion products formed on a high performance offshore platform steel in the en- vironment containing chloride ions has been investigated by scanning electron microscopy (SEM), X ray diffraction (XRD), electron probe microanalysis (EPMA) and electrochemical impedance spectroscopy (EIS). The results re- veal that the corrosion process can be divided into the initial stage and the later stage. The main constituents of rust layers are c~ FeOOH, 13-FeOOH, y-FeOOH, Fe:^()~ and large amounts of amorphous compounds. With increasing corrosion time, the mass fraction of a-FeOOH and Fe:~ O,, increased, while that of y-FeOOH and ^-FeOOH changed slightly. The enrichment of Cr and Ni at the inner/outer interface, especially the side of inner rust, can be observed in the later corrosion stage of Cr Ni steel, which can promote the formation of compact inner rust layer, impeding the transmission of corrosion mediums and slowing down the electrochemical reaction process.展开更多
LiMn_(x)Fe_(1-x)PO_(4)-C cathode materials for lithium ion batteries were synthesized via solid-state method using Li_(2)CO_(3),MnCO_(3),NH_(4)H_(2)PO_(4),FePO_(4) and sucrose as starting raw materials,followed by hig...LiMn_(x)Fe_(1-x)PO_(4)-C cathode materials for lithium ion batteries were synthesized via solid-state method using Li_(2)CO_(3),MnCO_(3),NH_(4)H_(2)PO_(4),FePO_(4) and sucrose as starting raw materials,followed by high-temperature reduction-annealing.A series of calcination experiments at different temperatures reveal that Mn^(2+)-containing materials exhibit a lower temperature for olivine phase formation,for example LiMn_(0.5)Fe_(0.5)PO_(4) olivine phase forms at 275℃,while manganese-free crystalline LiFePO_(4) generally forms at the required temperature of 350℃.Increasing Mn^(2+) content is found to enhance crystallization degree of LiMn_(x)Fe_(1-x)PO_(4) material prepared at lower calcination temperatures.X-ray photoelectron spectroscopy(XPS)results confirm that Mn valence state(+2)remains unchanged up to~250℃ when calcined in ambient atmosphere.The above-mentioned beneficial effect of manganese on phase formation and crystallization of olivine can be well attributed to the stable nature of Mn^(2+)and its strong propensity to form olivine phases.展开更多
基金supported by the National Natural Science Foundation of China(82071709,81971446,82171599,82374212)Global Select Project(DJK-LX-2022010)of the Institute of Health and Medicine,Hefei Comprehensive National Science CenterJoint Fund for New Medicine of USTC(YD9100002034)。
文摘The structural integrity of the sperm flagellum is essential for proper sperm function.Flagellar defects can result in male infertility,yet the precise mechanisms underlying this relationship are not fully understood.CCDC181,a coiled-coil domain-containing protein,is known to localize on sperm flagella and at the basal regions of motile cilia.Despite this knowledge,the specific functions of CCDC181 in flagellum biogenesis remain unclear.In this study,Ccdc181 knockout mice were generated.The absence of CCDC181 led to defective sperm head shaping and flagellum formation.Furthermore,the Ccdc181 knockout mice exhibited extremely low sperm counts,grossly aberrant sperm morphologies,markedly diminished sperm motility,and typical multiple morphological abnormalities of the flagella(MMAF).Additionally,an interaction between CCDC181 and the MMAF-related protein LRRC46 was identified,with CCDC181 regulating the localization of LRRC46 within sperm flagella.These findings suggest that CCDC181 plays a crucial role in both manchette formation and sperm flagellum biogenesis.
文摘When the induction motor is fed from the PWM VSI inverter, with and without torque enhancing function, the variations of the starting torque and the starting current versus the starting frequency are analyzed, based on the steady state equivalent circuit of the induction motor.The corresponding expressions are derived, and the corresponding curves are also drawn, from which the initial starting frequency range can be determined properly and easily. The initial starting frequency range is the common range, in which the starting torque should be high enough and the starting current low enough.Some other useful formulas are also derived.These results are significant for electrical drive designers to make the starting schemes. The effects of the increase of the stator and the rotor resistances on the starting torque and the initial starting frequency range are also discussed, which is caused by the skin effects of the high order harmonics present in the PWM inverter output voltage.
基金financially supported by the National Natural Science Foundation of China(No.51202014)。
文摘Ternary Sn-Sb-Cu alloy nanoparticles were successfully synthesized via co-reduction of metal chlorides in aqueous alkaline solution.The results of the transmission electron microscopy(TEM)show that the as prepared Sn-Sb-Cu nanoparticles have a specific hollow structure with a uniform particle size of 10-20 nm.As there are not any hard templates in the synthesis system,a galvanic displacement reaction mechanism is proposed to account for the formation of the hollow nanostructures.When the alloy powders are used as anode materials for lithium-ion batteries,they exhibit relatively high electrochemical capacity and good cyclic retention.The good electrochemical performance can be attributed to the inactive Cu species.During electrochemical reactions,the inactive copper phase in the hollow structure serves as a soft and ductile matrix,which alleviates the mechanical stresses caused by the severe volume change during lithium insertion and extraction.With their high reversible capacities,the Sn-Sb-Cu alloys are a promising candidate as the anode material of rechargeable lithium-ion batteries.
基金the National Science and Technology Pillar Program of China (2011BAE13B04)National Natural Science Foundation of China(51204047and U1660117)Fundamental Research Funds for the Central Universi-ties of China(N130407004)for the financial support
文摘A new hot-dip galvanizing method was employed on hot-rolled low carbon steel.The effects of Al contents on microstructure,micro-hardness and corrosion resistance of Zn-Al alloy coatings were systematically investigated.Phase composition,microstructure and element distribution in Zn-Al alloy coatings were analyzed using X-ray diffraction(XRD)and electron probe micro analysis(EPMA),respectively.It is found that Al content(0.6-6.0 wt.%)in galvanizing zinc affects surface quality and adhesion between coatings and matrix in the newly developed method.In addition,with increasing Al content,micro-hardness significantly increased due to the increase in Zn-Al eutectoid phases.Potentiodynamic polarization and electrochemical impedance spectroscopy(EIS)also revealed that increase in Al plays a noticeable role in improving the corrosion resistance of Zn-Al alloy coatings.
基金financially supported by the National Natural Science Foundation of China(No.51202014)
文摘LiFePOa composites were prepared by solid state reactions at different temperatures and time. The crystalline structure and morphology of the composites were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM), while X-ray absorption spectroscopy (XAS) was employed to characterize the crystallinity. Experimental results show that the electrochemical properties do not monotonously get better with the decrease of particle size and the traditional long reaction time is needless. Moreover, XAS is an effective technique to discover the change in crystallinity.
基金supported by the National Natural Science Foundation of China(grant numbers:31660728)the Key Research and Development Plan Project of Ningxia Hui Nationality Autonomous Region(grant numbers:2017BN04)。
文摘Objective:To investigate the mechanism by which total alkaloids of Sophora alopecuroides(TASA)and matrine(MT)impair biofilm to increase the susceptibility of Staphylococcus epidermidis(S.epidermidis)to ciprofloxacin.Methods:The minimum biofilm inhibitory concentration(mBIC)was determined using a 2-fold dilution method.Structure of biofilm of S.epidermidis was examined by Confocal Laser Scanning Microscope(CLSM).The cellular reactive oxygen species(ROS)was determined using a DCFH-DA assay.The key factors related to the regulation of ROS were accessed using respective kits.Results:TASA and MT were more beneficial to impair biofilm of S.epidermidis than ciprofloxacin(CIP)(P<0.05).TASA and MT were not easily developed resistance to biofilm-producing S.epidermidis.The mBIC of CIP decreased by 2-6-fold following the treatment of sub-biofilm inhibitory concentration(sub-BIC)TASA and MT,whereas the mBIC of CIP increased by 2-fold following a treatment of sub-BIC CIP from the first to sixth generations.TASA and MT can improve the production of ROS in biofilmproducing S.epidermidis.The ROS content was decreased 23%-33%following the treatment of submBIC CIP,whereas ROS content increased 7%-24%following treatment with TASA+CIP and MT+CIP combination from the first to sixth generations.Nitric oxide(NO)as a ROS,which was consistent with the previously confirmed relationship between ROS and drug resistance.Related regulatory factorssuperoxide dismutase(SOD)and glutathione peroxidase(GSH)could synergistically maintain the redox balance in vivo.Conclusion:TASA and MT enhanced reactive oxygen species to restore the susceptibility of S.epidermidis to ciprofloxacin.
基金the National Natural Science Foundation of China(No.51701173)。
文摘Ni-rich cathode material is one of the most promising materials for Li-ion batteries in electric vehicles.However,fading capacity,poor cyclic stability and high p H value are still major challenges,which suppress its practical application.In this study,spherical LiNi_(0.)9Co_(0.08)Al_(0.02)O_(2)powders with 0.4 wt%TiO_(2)coating layer were prepared by impregnation-hydrolysis method.Scanning electron microscopy(SEM),high-resolution transmission electron microscopy(HRTEM)and X-ray diffraction(XRD)results show that TiO_(2)is uniformly coated on the surface of LiNi_(0.)9Co_(0.08)Al_(0.02)O_(2)particle and slightly embedded into LiNi_(0.)9Co_(0.08)Al_(0.02)O_(2)particles.After 100 cycles at 2.0 C,0.4 wt%TiO_(2)-coated LiNi_(0.)9Co_(0.08)Al_(0.02)O_(2)electrode delivers much higher discharge capacity retention(77.0%)than the pristine LiNi_(0.)9Co_(0.08)Al_(0.02)O_(2)electrode(63.3%).The excellent cycling performance of 0.4 wt%Ti O_(2)-coated LiNi_(0.)9Co_(0.08)Al_(0.02)O_(2)electrode at a high discharge ratio is due to a TiO_(2)coating layer which can effectively reduce the direct contact between cathode material and electrolyte,suppress the oxidation of electrolyte,improve electrical conductivity of the electrode and increase the stability of the structure.
基金Item Sponsored by National Science-technology Support Plan Project of China(2012BAE04B02)National Natural Science Foundation of China(51271050)+1 种基金China Postdoctoral Science Foundation(2015M581346)Foundamental Research Funds for the Central Universities of China(N150203002)
文摘The effect of Sn on corrosion behavior of ferritic stainless steels in 20mass% H2SO4 was investigated by alternating current and direct current electrochemical methods and gravimetric tests at 25 ℃.The results show that Sn can effectively improve general corrosion resistance of ferritic stainless steels in H2SO4,mainly due to highly raised hydrogen evolution overpotential which is in favour of strong suppression of hydrogen evolution reaction,and inhibitive effect of dissolved Sn^2+ on elementary anodic reactions.With increasing Sn content,the better corrosion resistance can be reached.The Electrochemical Impedance Spectroscopy(EIS)includes four time constants and can be perfectly fitted by equivalent circuit:Rs(CdlRct)(QadsRads(RL1(L1(RL2L2)))).
基金Sponsored by the Fundamental Research Funds for the Central Universities of China(N120807001,N120407008)High Technology Research and Development Program of China(2007AA03Z504)Scientific Research Fund of Liaoning Provincial Education Department of China(L2013112)
文摘The characterization of corrosion products formed on a high performance offshore platform steel in the en- vironment containing chloride ions has been investigated by scanning electron microscopy (SEM), X ray diffraction (XRD), electron probe microanalysis (EPMA) and electrochemical impedance spectroscopy (EIS). The results re- veal that the corrosion process can be divided into the initial stage and the later stage. The main constituents of rust layers are c~ FeOOH, 13-FeOOH, y-FeOOH, Fe:^()~ and large amounts of amorphous compounds. With increasing corrosion time, the mass fraction of a-FeOOH and Fe:~ O,, increased, while that of y-FeOOH and ^-FeOOH changed slightly. The enrichment of Cr and Ni at the inner/outer interface, especially the side of inner rust, can be observed in the later corrosion stage of Cr Ni steel, which can promote the formation of compact inner rust layer, impeding the transmission of corrosion mediums and slowing down the electrochemical reaction process.
基金financially supported by the National Natural Science Foundation of China(No.51202014)。
文摘LiMn_(x)Fe_(1-x)PO_(4)-C cathode materials for lithium ion batteries were synthesized via solid-state method using Li_(2)CO_(3),MnCO_(3),NH_(4)H_(2)PO_(4),FePO_(4) and sucrose as starting raw materials,followed by high-temperature reduction-annealing.A series of calcination experiments at different temperatures reveal that Mn^(2+)-containing materials exhibit a lower temperature for olivine phase formation,for example LiMn_(0.5)Fe_(0.5)PO_(4) olivine phase forms at 275℃,while manganese-free crystalline LiFePO_(4) generally forms at the required temperature of 350℃.Increasing Mn^(2+) content is found to enhance crystallization degree of LiMn_(x)Fe_(1-x)PO_(4) material prepared at lower calcination temperatures.X-ray photoelectron spectroscopy(XPS)results confirm that Mn valence state(+2)remains unchanged up to~250℃ when calcined in ambient atmosphere.The above-mentioned beneficial effect of manganese on phase formation and crystallization of olivine can be well attributed to the stable nature of Mn^(2+)and its strong propensity to form olivine phases.