A novel matrix metalloproteinase (MMP) was identified from leukocytes and found to be specifically expressedby peripheral blood leukocytes among 29 different tissuesexamined. Named leukolysin, it encodes for 562 resid...A novel matrix metalloproteinase (MMP) was identified from leukocytes and found to be specifically expressedby peripheral blood leukocytes among 29 different tissuesexamined. Named leukolysin, it encodes for 562 residueswith a conserved MMP structure, i.e., pre-, pro-, catalytic , hinge- and hemopexin-like domains, but also a RXK/RRmotif, known for its role in MMP zymogen activation, anda C-terminal hydrophobic segment. Overall, leukolysindisplays the strongest homology to the newly identifiedMT-MMP subgroup with 45% and 39% identities to MT4and MT1-MMPs vs 30% and 31.5% to MMP1 and 3 respectively. Unlike MT4-MMP whose proteolytic activityremains undefined, a C-terminally truncated leukolysin isexpressed as a strong gelatinolytic species at 28 kDa whichis derived from a cell-associated 34 kDa proenzyme, presumably by furin or proprotein convertase mediated removal of the propeptide (-6 kDa). By green fluorescentprotein (GFP) tagging, the intracellular proenzyme is localized to granules throughout the cell, suggesting thatactivation occur immediately prior to secretion. Taken together, leukolysin may be part of the proteolytic arsenaldeployed by leukocytes during inflammatory responses.展开更多
In order to determine the effect of heat treatment on the mechanical and wear properties of Zn−40Al−2Cu−2Si alloy,different heat treatments including homogenization followed by air-cooling(H1),homogenization followed ...In order to determine the effect of heat treatment on the mechanical and wear properties of Zn−40Al−2Cu−2Si alloy,different heat treatments including homogenization followed by air-cooling(H1),homogenization followed by furnace-cooling(H2),stabilization(T5)and quench−aging(T6 and T7)were applied.The effects of these heat treatments on the mechanical and tribological properties of the alloy were studied by metallography and,mechanical and wear tests in comparison with SAE 65 bronze.The wear tests were performed using a block on cylinder type test apparatus.The hardness,tensile strength and compressive strength of the alloy increase by the application of H1 and T6 heat treatments,and all the heat treatments except T6,increase its elongation to fracture.H1,T5 and T6 heat treatments cause a reduction in friction coefficient and wear volume of the alloy.However,this alloy exhibits the lowest friction coefficient and wear volume after T6 heat treatment.Therefore,T6 heat treatment appears to be the best process for the lubricated tribological applications of this alloy at a pressure of 14 MPa.However,Zn−40Al−2Cu−2Si alloy in the as-cast and heat-treated conditions shows lower wear loss or higher wear resistance than the bronze.展开更多
Diarylethene derivatives are a class of fascinating photochromic materials because of their open and closed isomers with different absorption spectra and many other characteristics.To reveal the detailed structure and...Diarylethene derivatives are a class of fascinating photochromic materials because of their open and closed isomers with different absorption spectra and many other characteristics.To reveal the detailed structure and optoelectronic properties as well as the effect of metal centres and substituents on them,a systematic study on a series of diarylethene derivatives and their Re(I),Pt(II),and Ir(III) complexes was performed via theoretical calculation.The optimized geometries,electronic properties,frontier molecular orbitals,ionization potentials,electron affinities,reorganization energies,and absorption spectra for both of their open-and closed-isomers have been calculated and analyzed.Metal-coordination and substituents exhibit great influence on the photophysical,charge-injection and-transporting characteristics.In addition,the binding of F-with the boron atom of dimesitylboryl group through Lewis acid/base interactions also induces great changes of structural,photophysical and electronic properties for these diarylethene derivatives,and consequently the compound with the substituent of dimesitylboryl group can be used as selective near-infrared phosphorescent F-probe.展开更多
文摘A novel matrix metalloproteinase (MMP) was identified from leukocytes and found to be specifically expressedby peripheral blood leukocytes among 29 different tissuesexamined. Named leukolysin, it encodes for 562 residueswith a conserved MMP structure, i.e., pre-, pro-, catalytic , hinge- and hemopexin-like domains, but also a RXK/RRmotif, known for its role in MMP zymogen activation, anda C-terminal hydrophobic segment. Overall, leukolysindisplays the strongest homology to the newly identifiedMT-MMP subgroup with 45% and 39% identities to MT4and MT1-MMPs vs 30% and 31.5% to MMP1 and 3 respectively. Unlike MT4-MMP whose proteolytic activityremains undefined, a C-terminally truncated leukolysin isexpressed as a strong gelatinolytic species at 28 kDa whichis derived from a cell-associated 34 kDa proenzyme, presumably by furin or proprotein convertase mediated removal of the propeptide (-6 kDa). By green fluorescentprotein (GFP) tagging, the intracellular proenzyme is localized to granules throughout the cell, suggesting thatactivation occur immediately prior to secretion. Taken together, leukolysin may be part of the proteolytic arsenaldeployed by leukocytes during inflammatory responses.
基金This work was supported by Scientific Research Projects Coordination Unit of Karadeniz Technical University,Turkey(No.2008.112.03.1).
文摘In order to determine the effect of heat treatment on the mechanical and wear properties of Zn−40Al−2Cu−2Si alloy,different heat treatments including homogenization followed by air-cooling(H1),homogenization followed by furnace-cooling(H2),stabilization(T5)and quench−aging(T6 and T7)were applied.The effects of these heat treatments on the mechanical and tribological properties of the alloy were studied by metallography and,mechanical and wear tests in comparison with SAE 65 bronze.The wear tests were performed using a block on cylinder type test apparatus.The hardness,tensile strength and compressive strength of the alloy increase by the application of H1 and T6 heat treatments,and all the heat treatments except T6,increase its elongation to fracture.H1,T5 and T6 heat treatments cause a reduction in friction coefficient and wear volume of the alloy.However,this alloy exhibits the lowest friction coefficient and wear volume after T6 heat treatment.Therefore,T6 heat treatment appears to be the best process for the lubricated tribological applications of this alloy at a pressure of 14 MPa.However,Zn−40Al−2Cu−2Si alloy in the as-cast and heat-treated conditions shows lower wear loss or higher wear resistance than the bronze.
基金supported by the National Basic Research Program of China (973 Program,2009CB930601 and 2012CB933301)National Natural Science Foundation of China (21174064,21171098)+4 种基金Natural Science Fund for Colleges and Universities in Jiangsu Province(10KJB430010)the Ministry of Education of China (IRT1148)Key Projects in Jiangsu Province for International Cooperation (BZ2010043)Nanjing University of Posts and Telecommunications (NY210029)Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘Diarylethene derivatives are a class of fascinating photochromic materials because of their open and closed isomers with different absorption spectra and many other characteristics.To reveal the detailed structure and optoelectronic properties as well as the effect of metal centres and substituents on them,a systematic study on a series of diarylethene derivatives and their Re(I),Pt(II),and Ir(III) complexes was performed via theoretical calculation.The optimized geometries,electronic properties,frontier molecular orbitals,ionization potentials,electron affinities,reorganization energies,and absorption spectra for both of their open-and closed-isomers have been calculated and analyzed.Metal-coordination and substituents exhibit great influence on the photophysical,charge-injection and-transporting characteristics.In addition,the binding of F-with the boron atom of dimesitylboryl group through Lewis acid/base interactions also induces great changes of structural,photophysical and electronic properties for these diarylethene derivatives,and consequently the compound with the substituent of dimesitylboryl group can be used as selective near-infrared phosphorescent F-probe.
