Cubic boron nitride(cBN)is a kind of artificial(synthetic)crystal.Transverse electro-optic modulation in a minute cBN sample was carried out.Basing on the practical form of the crystal,we established the theoretical a...Cubic boron nitride(cBN)is a kind of artificial(synthetic)crystal.Transverse electro-optic modulation in a minute cBN sample was carried out.Basing on the practical form of the crystal,we established the theoretical and experimental method according to the sample.For the first time,the linear electro-optic effect was observed in cBN,and half-wave voltage of the cBN sample was measured successfully.Furthermore,its linear electro-optic coefficient was calculated at 1.17×10?14 m/V.展开更多
It has been reported that organotins can inhibit the proteasomal chymotrypsin-like activity and induce cell death,but the interaction mode of organotins with proteasome has not been well defined.In this study,the IC50...It has been reported that organotins can inhibit the proteasomal chymotrypsin-like activity and induce cell death,but the interaction mode of organotins with proteasome has not been well defined.In this study,the IC50 of butyltins and phenyltins against the proteasomal activity and the nature of their inhibition were investigated.It was found that both mono-and di-organotins were weak,reversible inhibitors against the proteasome,while tributyltin and triphenyltin were potent,irreversible proteasome inhibitors.In silico studies using the reversible organotin proteasome inhibitors demonstrated a tight correlation of the estimated proteasomal inhibition constants(Ki) with the experimental IC50 values for proteasome inhibition.Furthermore,the Sn atom in TBT and TPT was found susceptible to form a coordinate bond with Thr 1 OY of the β5 subunit,which may account for the irreversible proteasome inhibition.The computational docking approach well predicted the inhibition nature of organotins toward the proteasomal chymotrypsin-like activity.This predictive model might aid in understanding the cytotoxic behavior of similar organometallic compounds.展开更多
The electric properties of nonintentionally doped n-cubic boron nitride(cBN)crystal are investigated.The cBN crystal was transformed from hexagonal-boron nitride(h-BN)under high pressure(HP)and high temperature(HT)usi...The electric properties of nonintentionally doped n-cubic boron nitride(cBN)crystal are investigated.The cBN crystal was transformed from hexagonal-boron nitride(h-BN)under high pressure(HP)and high temperature(HT)using magnesium powder as catalyst.At room temperature,the current-voltage(I-V)characteristics of cBN crystal are measured and found to be nonlinear.When the electric field is in the range of(1―1.5)×105 V/cm,the avalanche breakdown occurs inside the whole cBN crystal.At this same time,the bright blue-violet with the wavelength of 380―400 nm from the cBN crystal is observed.When measuring the I-V curve after breakdown of cBN crystal,the current-controlled differential negative resistance phenomenon is observed.The breakdown is repeatable.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.60176009,69976013 and 69676025)the Science and Technology Bureau Foundation of Jilin Province(Grant No.20010580).
文摘Cubic boron nitride(cBN)is a kind of artificial(synthetic)crystal.Transverse electro-optic modulation in a minute cBN sample was carried out.Basing on the practical form of the crystal,we established the theoretical and experimental method according to the sample.For the first time,the linear electro-optic effect was observed in cBN,and half-wave voltage of the cBN sample was measured successfully.Furthermore,its linear electro-optic coefficient was calculated at 1.17×10?14 m/V.
基金supported by the National Natural Science Foundation of China (20977007)the Scientific Research Foundation for the Returned Overseas Chinese Scholars,Ministry of Education of ChinaState Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences (KF-2008-12)
文摘It has been reported that organotins can inhibit the proteasomal chymotrypsin-like activity and induce cell death,but the interaction mode of organotins with proteasome has not been well defined.In this study,the IC50 of butyltins and phenyltins against the proteasomal activity and the nature of their inhibition were investigated.It was found that both mono-and di-organotins were weak,reversible inhibitors against the proteasome,while tributyltin and triphenyltin were potent,irreversible proteasome inhibitors.In silico studies using the reversible organotin proteasome inhibitors demonstrated a tight correlation of the estimated proteasomal inhibition constants(Ki) with the experimental IC50 values for proteasome inhibition.Furthermore,the Sn atom in TBT and TPT was found susceptible to form a coordinate bond with Thr 1 OY of the β5 subunit,which may account for the irreversible proteasome inhibition.The computational docking approach well predicted the inhibition nature of organotins toward the proteasomal chymotrypsin-like activity.This predictive model might aid in understanding the cytotoxic behavior of similar organometallic compounds.
基金the Research Foundation of Zhuhai College of Jinan University for recruited excellent talents(Grant No.510062)
文摘The electric properties of nonintentionally doped n-cubic boron nitride(cBN)crystal are investigated.The cBN crystal was transformed from hexagonal-boron nitride(h-BN)under high pressure(HP)and high temperature(HT)using magnesium powder as catalyst.At room temperature,the current-voltage(I-V)characteristics of cBN crystal are measured and found to be nonlinear.When the electric field is in the range of(1―1.5)×105 V/cm,the avalanche breakdown occurs inside the whole cBN crystal.At this same time,the bright blue-violet with the wavelength of 380―400 nm from the cBN crystal is observed.When measuring the I-V curve after breakdown of cBN crystal,the current-controlled differential negative resistance phenomenon is observed.The breakdown is repeatable.
