Mesenchymal stem cells(MSCs) are important cell sources in cartilage tissue development and homeostasis,and multiple strategies have been developed to improve MSCs chondrogenic differentiation with an aim of promoting...Mesenchymal stem cells(MSCs) are important cell sources in cartilage tissue development and homeostasis,and multiple strategies have been developed to improve MSCs chondrogenic differentiation with an aim of promoting cartilage regeneration.Here we report the effects of combining nanosecond pulsed electric fields(ns PEFs) followed by treatment with ghrelin(a hormone that stimulates release of growth hormone) to regulate chondrogenesis of MSCs.ns PEFs and ghrelin were observed to separately enhance the chondrogenesis of MSCs,and the effects were significantly enhanced when the bioelectric stimulation and hormone were combined,which in turn improved osteochondral tissue repair of these cells within Sprague Dawley rats.We further found that ns PEFs can prime MSCs to be more receptive to subsequent stimuli of differentiation by upregulated Oct4/Nanog and activated JNK signaling pathway.Ghrelin initiated chondrogenic differentiation by activation of ERK1/2 signaling pathway,and RNA-seq results indicated 243 genes were regulated,and JAK-STAT signaling pathway was involved.Interestingly,the sequential order of applying these two stimuli is critical,with ns PEFs pretreatment followed by ghrelin enhanced chondrogenesis of MSCs in vitro and subsequent cartilage regeneration in vivo,but not vice versa.This synergistic prochondrogenic effects provide us new insights and strategies for future cell-based therapies.展开更多
Water-gas shift reaction catalyst at lower temperature （200-400 ℃） may improve the conversion of carbon monoxide. But carbonyl sulfide was found to be present over the sulfided cobaltmolybdenum/alumina catalyst for...Water-gas shift reaction catalyst at lower temperature （200-400 ℃） may improve the conversion of carbon monoxide. But carbonyl sulfide was found to be present over the sulfided cobaltmolybdenum/alumina catalyst for water-gas shift reaction. The influences of temperature, space velocity, and gas components on the formation of carbonyl sulfide over sulfided cobalt-molybdenum/alumina catalyst B303Q at 200-400 ℃ were studied in a tubular fixed-bed quartz-glass reactor under simulated water-gas shift conditions. The experimental results showed that the yield of carbonyl sulfide over B303Q catalyst reached a maximum at 220 ℃ with the increase in temperature, sharply decreased with the increase in space velocity and the content of water vapor, increased with the increase in the content of carbon monoxide and carbon dioxide, and its yield increased and then reached a stable value with the increase in the content of hydrogen and hydrogen sulfide. The formation mechanism of carbonyl sulfide over B303Q catalyst at 200-400 ℃ was discussed on the basis of how these factors influence the formation of COS. The yield of carbonyl sulfide over B303Q catalyst at 200-400 ℃ was the combined result of two reactions, that is, COS was first produced by the reaction of carbon monoxide with hydrogen sulfide, and then the as-produced COS was converted to hydrogen sulfide and carbon dioxide by hydrolysis. The mechanism of COS formation is assumed as follows： sulfur atoms in the Co9Ss-MoS2/Al2O3 crystal lattice were easily removed and formed carbonyl sulfide with CO, and then hydrogen sulfide in the water-gas shift gas reacted with the crystal lattice oxygen atoms in CoO-MoOa/Al2O3 to form Co9S8-MoS2/Al2O3. This mechanism for the formation of COS over water-gas shift catalyst B303Q is in accordance with the Mars-Van Krevelen＇s redox mechanism over metal sulfide.展开更多
Lactate dehydrogenase and malate dehydrogenase are the two main alpha-hydroxy acid dehydrogenases in the human body.We investigated the catalytic properties of human lactate dehydrogenase LDHC,LDHL6A and malate dehydr...Lactate dehydrogenase and malate dehydrogenase are the two main alpha-hydroxy acid dehydrogenases in the human body.We investigated the catalytic properties of human lactate dehydrogenase LDHC,LDHL6A and malate dehydrogenase MDH1 on aromatic α-keto acids phenylpyruvic acid,p-hydroxyphenylpyruvic acid and 3,4-dihydroxyphenylpyruvic acid.The optimum temperatures for LDHC,LDHL6A,and MDH1 are 37℃,35℃,and 45℃,respectively;and the optimum pH is 6.5,6.5,and 5.5,respectively.The K_(m)of LDHC for phenylpyruvic acid and 3,4-dihydroxyphenylpyruvic acid were 0.90 mM and 0.92 mM,respectively.LDHL6A has a high affinity for phenylpyruvic acid and 3,4-dihydroxyphenylpyruvic acid with K_(m)of 0.77 mM and 0.80 mM,respectively;MDH1 has an extremely high affinity(K_(m)=0.46 mM)and catalytic efficiency(k_(cat)/K_(m)=23.87 s^(-1)·mM^(-1))for p-hydroxyphenylpyruvic acid.It also has a high affinity for 3,4-dihydroxyphenylpyruvic acid with a K_(m)of 0.90 mM,but with a low affinity for phenylpyruvic acid(K_(m)=3.76 mM).The catalytic properties of human LDHC,LDHL6A,and MDH1 for the abovementioned aromatic α-keto acids may be one of the sources of L-phenyllactic acid,L-p-hydroxyphenyllactic acid,and L-3,4-dihydroxyphenyllactic acid in humans.展开更多
Tracking-Learning-Detection( TLD) is an adaptive tracking algorithm,which tracks by learning the appearance of the object as the video progresses and shows a good performance in long-term tracking task.But our experim...Tracking-Learning-Detection( TLD) is an adaptive tracking algorithm,which tracks by learning the appearance of the object as the video progresses and shows a good performance in long-term tracking task.But our experiments show that under some scenarios,such as non-uniform illumination changing,serious occlusion,or motion-blurred,it may fails to track the object. In this paper,to surmount some of these shortages,especially for the non-uniform illumination changing,and give full play to the performance of the tracking-learning-detection framework, we integrate the local binary pattern( LBP) with the cascade classifiers,and define a new classifier named ULBP( Uniform Local Binary Pattern) classifiers. When the object appearance has rich texture features,the ULBP classifier will work instead of the nearest neighbor classifier in TLD algorithm,and a recognition module is designed to choose the suitable classifier between the original nearest neighbor( NN) classifier and the ULBP classifier. To further decrease the computing load of the proposed tracking approach,Kalman filter is applied to predict the searching range of the tracking object.A comprehensive study has been conducted to confirm the effectiveness of the proposed algorithm (TLD _ULBP),and different multi-property datasets were used. The quantitative evaluations show a significant improvement over the original TLD,especially in various lighting case.展开更多
基金supported by the National Key Research and Development Program of China (2019YFA0111900)the National Natural Science Foundation of China (81772334)。
文摘Mesenchymal stem cells(MSCs) are important cell sources in cartilage tissue development and homeostasis,and multiple strategies have been developed to improve MSCs chondrogenic differentiation with an aim of promoting cartilage regeneration.Here we report the effects of combining nanosecond pulsed electric fields(ns PEFs) followed by treatment with ghrelin(a hormone that stimulates release of growth hormone) to regulate chondrogenesis of MSCs.ns PEFs and ghrelin were observed to separately enhance the chondrogenesis of MSCs,and the effects were significantly enhanced when the bioelectric stimulation and hormone were combined,which in turn improved osteochondral tissue repair of these cells within Sprague Dawley rats.We further found that ns PEFs can prime MSCs to be more receptive to subsequent stimuli of differentiation by upregulated Oct4/Nanog and activated JNK signaling pathway.Ghrelin initiated chondrogenic differentiation by activation of ERK1/2 signaling pathway,and RNA-seq results indicated 243 genes were regulated,and JAK-STAT signaling pathway was involved.Interestingly,the sequential order of applying these two stimuli is critical,with ns PEFs pretreatment followed by ghrelin enhanced chondrogenesis of MSCs in vitro and subsequent cartilage regeneration in vivo,but not vice versa.This synergistic prochondrogenic effects provide us new insights and strategies for future cell-based therapies.
基金the National Basic Research Program of China (No.2005CB221203)
文摘Water-gas shift reaction catalyst at lower temperature （200-400 ℃） may improve the conversion of carbon monoxide. But carbonyl sulfide was found to be present over the sulfided cobaltmolybdenum/alumina catalyst for water-gas shift reaction. The influences of temperature, space velocity, and gas components on the formation of carbonyl sulfide over sulfided cobalt-molybdenum/alumina catalyst B303Q at 200-400 ℃ were studied in a tubular fixed-bed quartz-glass reactor under simulated water-gas shift conditions. The experimental results showed that the yield of carbonyl sulfide over B303Q catalyst reached a maximum at 220 ℃ with the increase in temperature, sharply decreased with the increase in space velocity and the content of water vapor, increased with the increase in the content of carbon monoxide and carbon dioxide, and its yield increased and then reached a stable value with the increase in the content of hydrogen and hydrogen sulfide. The formation mechanism of carbonyl sulfide over B303Q catalyst at 200-400 ℃ was discussed on the basis of how these factors influence the formation of COS. The yield of carbonyl sulfide over B303Q catalyst at 200-400 ℃ was the combined result of two reactions, that is, COS was first produced by the reaction of carbon monoxide with hydrogen sulfide, and then the as-produced COS was converted to hydrogen sulfide and carbon dioxide by hydrolysis. The mechanism of COS formation is assumed as follows： sulfur atoms in the Co9Ss-MoS2/Al2O3 crystal lattice were easily removed and formed carbonyl sulfide with CO, and then hydrogen sulfide in the water-gas shift gas reacted with the crystal lattice oxygen atoms in CoO-MoOa/Al2O3 to form Co9S8-MoS2/Al2O3. This mechanism for the formation of COS over water-gas shift catalyst B303Q is in accordance with the Mars-Van Krevelen＇s redox mechanism over metal sulfide.
文摘Lactate dehydrogenase and malate dehydrogenase are the two main alpha-hydroxy acid dehydrogenases in the human body.We investigated the catalytic properties of human lactate dehydrogenase LDHC,LDHL6A and malate dehydrogenase MDH1 on aromatic α-keto acids phenylpyruvic acid,p-hydroxyphenylpyruvic acid and 3,4-dihydroxyphenylpyruvic acid.The optimum temperatures for LDHC,LDHL6A,and MDH1 are 37℃,35℃,and 45℃,respectively;and the optimum pH is 6.5,6.5,and 5.5,respectively.The K_(m)of LDHC for phenylpyruvic acid and 3,4-dihydroxyphenylpyruvic acid were 0.90 mM and 0.92 mM,respectively.LDHL6A has a high affinity for phenylpyruvic acid and 3,4-dihydroxyphenylpyruvic acid with K_(m)of 0.77 mM and 0.80 mM,respectively;MDH1 has an extremely high affinity(K_(m)=0.46 mM)and catalytic efficiency(k_(cat)/K_(m)=23.87 s^(-1)·mM^(-1))for p-hydroxyphenylpyruvic acid.It also has a high affinity for 3,4-dihydroxyphenylpyruvic acid with a K_(m)of 0.90 mM,but with a low affinity for phenylpyruvic acid(K_(m)=3.76 mM).The catalytic properties of human LDHC,LDHL6A,and MDH1 for the abovementioned aromatic α-keto acids may be one of the sources of L-phenyllactic acid,L-p-hydroxyphenyllactic acid,and L-3,4-dihydroxyphenyllactic acid in humans.
基金Sponsored by the National Natural Science Foundation of China(Grant No.61573057)the National Science and Technology Supporting Project(Grant No.2015BAF08B01)
文摘Tracking-Learning-Detection( TLD) is an adaptive tracking algorithm,which tracks by learning the appearance of the object as the video progresses and shows a good performance in long-term tracking task.But our experiments show that under some scenarios,such as non-uniform illumination changing,serious occlusion,or motion-blurred,it may fails to track the object. In this paper,to surmount some of these shortages,especially for the non-uniform illumination changing,and give full play to the performance of the tracking-learning-detection framework, we integrate the local binary pattern( LBP) with the cascade classifiers,and define a new classifier named ULBP( Uniform Local Binary Pattern) classifiers. When the object appearance has rich texture features,the ULBP classifier will work instead of the nearest neighbor classifier in TLD algorithm,and a recognition module is designed to choose the suitable classifier between the original nearest neighbor( NN) classifier and the ULBP classifier. To further decrease the computing load of the proposed tracking approach,Kalman filter is applied to predict the searching range of the tracking object.A comprehensive study has been conducted to confirm the effectiveness of the proposed algorithm (TLD _ULBP),and different multi-property datasets were used. The quantitative evaluations show a significant improvement over the original TLD,especially in various lighting case.
