The overall reaction was determined on the basis of the dissociation constant of TBA and the ratio of the ligand to the rare earth ion in the complex.The rate law,rate constants and acitivition energies for the reacti...The overall reaction was determined on the basis of the dissociation constant of TBA and the ratio of the ligand to the rare earth ion in the complex.The rate law,rate constants and acitivition energies for the reaction of La^(3+),Gd^(3+)and Ho^(3+)with TBA were studied.It is shown in the study that prerequisites for performing differential rate analysis for binary rare earths with TBA are that the pseudo-first-order parallel reaction mechanism should be conformed with,no multinuclear complex would be formed and the co-coloration effects could be neglected.展开更多
Fatty acids(FAs)are an important class of functional small molecules and participate in a variety of life biological processes.This experiment proposed a liquid chromatography–quadrupole-Qrbitrap mass spectrometry(LC...Fatty acids(FAs)are an important class of functional small molecules and participate in a variety of life biological processes.This experiment proposed a liquid chromatography–quadrupole-Qrbitrap mass spectrometry(LC–Q-Orbitrap MS)method to perform FA profiling under parallel reaction monitoring(PRM)acquisition mode.The FA was derivatized by 2-dimethylaminoethylamine(DMED)to increase the ionization e fficiency and provide the characterized fragment pattern.The mass spectra obtained from full scan,multiple ion monitoring(MIM),and PRM were compared.The results showed that the protonated ion of FA+DMED–H2O was detected and the neutral loss of 45.06 Da was observed in the tandem mass spectrum.The PRM method provided the highest selectivity and sensitivity for FA detection with the help of accurate mass weight and specific neutral loss-based fragments.The method validation was performed using the FA standards and pooled quality control serum sample,which showed that the established method had good repeatability,stability,and linearity.Finally,the developed method was successfully applied to analyze the rat serum and brain tissue samples for the drug e ffi-cacy evaluation of gross saponin of Tribulus terrestris L.fruit(GSTTF)against middle cerebral artery occlusion(MCAO)-induced ischemic stroke.This method has extensive practicability and great potential in the detection of FA,especially for the analysis of samples with complex matrices.展开更多
Designing catalyst to achieve ammonia synthesis at mild conditions is a meaningful challenge in catalysis community.Defective g-C_(3)N_(4)nanosheet supported single-cluster ruthenium and iron catalysts were investigat...Designing catalyst to achieve ammonia synthesis at mild conditions is a meaningful challenge in catalysis community.Defective g-C_(3)N_(4)nanosheet supported single-cluster ruthenium and iron catalysts were investigated for their ammonia synthesis performance.Based on density functional theory(DFT)calculations and microkinetic simulations,Ru_(3)single-cluster anchored on defective g-C3N4 nanosheet(Ru_(3)/Nv-g-C_(3)N_(4))has a turnover frequency(TOF)5.8 times higher than the Ru(0001)step surface at industrial reaction conditions of 673 K and 100 bar for ammonia synthesis.In other words,similar TOFs could be achieved on Ru_(3)/Nv-g-C_(3)N_(4)at much milder conditions(623 K,30 bar)than on Ru(0001)(673 K,100 bar).Our computations reveal the reaction proceeds parallelly on Ru_(3)/Nv-g-C_(3)N_(4)through both dissociative and alternative associative mechanisms at typical reaction conditions(600–700 K,10–100 bar);N–N bond cleavage of*N2 and*NNH from the two respective pathways controls the reaction collectively.With increasing temperatures or decreasing pressures,the dissociative mechanism gradually prevails and associative mechanism recedes.In comparison,Fe_(3)/Nv-g-C_(3)N_(4)catalyst shows a much lower catalytic activity than Ru3/Nv-g-C_(3)N_(4)by two orders of magnitude and the reaction occurs solely through the dissociative pathway.The finding provides a prospective candidate and deepens the mechanistic understanding for ammonia synthesis catalyzed by single-cluster catalysts(SCCs).展开更多
Approximate analytical expressions of overall effectiveness factors for parallel catalytic reac-tions occurring in a spherical catalyst pellet with both internal and external mass transfer resistancesare obtained afte...Approximate analytical expressions of overall effectiveness factors for parallel catalytic reac-tions occurring in a spherical catalyst pellet with both internal and external mass transfer resistancesare obtained after taking the information given by asymptotic solutions valid for small and largevalues of Thiele moduli.This approximate procedure is feasible for power law as well asLangmuir-Hinshelwood kinetics and the agreement between the approximation and the numerical re-sults is good enough for practical purposes.Moreover,the method does not require any iterative ortrial-and-error computation,and can be conveniently applied in most practical calculations for reac-tors giving reliable results.展开更多
Ogura cytoplasmic male sterility(Ogura CMS)is extensively applied in hybrid seed production in cruciferous crops.However,the posttranscriptional molecular basis of Ogura CMS in cruciferous crops remains elusive.Here,a...Ogura cytoplasmic male sterility(Ogura CMS)is extensively applied in hybrid seed production in cruciferous crops.However,the posttranscriptional molecular basis of Ogura CMS in cruciferous crops remains elusive.Here,a data-independent acquisition-based proteomic approach coupled with a parallel reaction monitoring-based targeted proteomic assay was used to analyze the proteome dynamics of Ogura CMS cabbage line RM and its maintainer line RF during floral bud development to obtain insights into the mechanism underlying Ogura CMS in cruciferous crops.A total of 9162 proteins corresponding to 61464 peptides were identified in RM and RF floral buds.The proteomic fluctuation of RM was weaker than that of RF.Differences in protein expression between RM and RF gradually enlarged with floral bud development.Fifteen continually up-regulated and eight continually down-regulated proteins were found in RM relative to RF throughout floral bud development.Differentially expressed proteins between RM and RF during floral bud development were implicated in the endoplasmic reticulum(ER)-associated protein processing pathway,in which most of them exhibited down-regulated expression in RM.These data suggest that ER-associated protein processing may be involved in pollen abortion in Ogura CMS cabbage by inhibiting the expression of critical factors.Our findings not only deepen the understanding of the molecular mechanisms of Ogura CMS in cruciferous crops but also provide better guidance for applying Ogura CMS in the hybrid breeding of cruciferous crops.展开更多
Dialkylamino-4(3H)-quinazolinones 4 were rapidly synthesized by a solution-phase parallel synthetic method, which includes aza-Wittig reaction of iminophosphorane 1 with aromatic isocynate to give carbodiimide 2 and s...Dialkylamino-4(3H)-quinazolinones 4 were rapidly synthesized by a solution-phase parallel synthetic method, which includes aza-Wittig reaction of iminophosphorane 1 with aromatic isocynate to give carbodiimide 2 and subsequent reaction of 2 with various aliphatic secondary amine in a parallel fashion.展开更多
BACKGROUND Colorectal cancer(CRC)is the second leading cause of cancer-related death,with high morbidity worldwide.There is an urgent need to find reliable diagnostic biomarkers of CRC and explore the underlying molec...BACKGROUND Colorectal cancer(CRC)is the second leading cause of cancer-related death,with high morbidity worldwide.There is an urgent need to find reliable diagnostic biomarkers of CRC and explore the underlying molecular mechanisms.Exosomes are involved in intercellular communication and participate in multiple pathological processes,serving as an important part of the tumor microenvironment.AIM To investigate the proteomic characteristics of CRC tumor-derived exosomes and to identify candidate exosomal protein markers for CRC.METHODS In this study,10 patients over 50 years old who were diagnosed with moderately differentiated adenocarcinoma were recruited.We paired CRC tissues and adjacent normal intestinal tissues(>5 cm)to form the experimental and control groups.Purified exosomes were extracted separately from each tissue sample.Data-independent acquisition mass spectrometry was implemented in 8 matched samples of exosomes to explore the proteomic expression profiles,and differentially expressed proteins(DEPs)were screened by bioinformatics analysis.Promising exosomal proteins were verified using parallel reaction monitoring(PRM)analysis in 10 matched exosome samples.RESULTS A total of 1393 proteins were identified in the CRC tissue group,1304 proteins were identified in the adjacent tissue group,and 283 proteins were significantly differentially expressed between them.Enrichment analysis revealed that DEPs were involved in multiple biological processes related to cytoskeleton construction,cell movement and migration,immune response,tumor growth and telomere metabolism,as well as ECM-receptor interaction,focal adhesion and mTOR signaling pathways.Six differentially expressed exosomal proteins(NHP2,OLFM4,TOP1,SAMP,TAGL and TRIM28)were validated by PRM analysis and evaluated by receiver operating characteristic curve(ROC)analysis.The area under the ROC curve was 0.93,0.96,0.97,0.78,0.75,and 0.88(P<0.05)for NHP2,OLFM4,TOP1,SAMP,TAGL,and TRIM28,respectively,indicating their good ability to distinguish CRC tissues from adjacent intestinal tissues.CONCLUSION In our study,comprehensive proteomic profiles were obtained for CRC tissue exosomes.Six exosomal proteins,NHP2,OLFM4,TOP1,SAMP,TAGL and TRIM28,may be promising diagnostic markers and effective therapeutic targets for CRC,but further experimental investigation is needed.展开更多
基金The Project was supported by the National Natural Science Foundation of China
文摘The overall reaction was determined on the basis of the dissociation constant of TBA and the ratio of the ligand to the rare earth ion in the complex.The rate law,rate constants and acitivition energies for the reaction of La^(3+),Gd^(3+)and Ho^(3+)with TBA were studied.It is shown in the study that prerequisites for performing differential rate analysis for binary rare earths with TBA are that the pseudo-first-order parallel reaction mechanism should be conformed with,no multinuclear complex would be formed and the co-coloration effects could be neglected.
基金supported by the National Natural Science Foundation of China(82104366)the Department of Science and Technology of Jilin Province(20210101426JC and 20220505047ZP)the Changchun University of Chinese Medicine(202326)。
文摘Fatty acids(FAs)are an important class of functional small molecules and participate in a variety of life biological processes.This experiment proposed a liquid chromatography–quadrupole-Qrbitrap mass spectrometry(LC–Q-Orbitrap MS)method to perform FA profiling under parallel reaction monitoring(PRM)acquisition mode.The FA was derivatized by 2-dimethylaminoethylamine(DMED)to increase the ionization e fficiency and provide the characterized fragment pattern.The mass spectra obtained from full scan,multiple ion monitoring(MIM),and PRM were compared.The results showed that the protonated ion of FA+DMED–H2O was detected and the neutral loss of 45.06 Da was observed in the tandem mass spectrum.The PRM method provided the highest selectivity and sensitivity for FA detection with the help of accurate mass weight and specific neutral loss-based fragments.The method validation was performed using the FA standards and pooled quality control serum sample,which showed that the established method had good repeatability,stability,and linearity.Finally,the developed method was successfully applied to analyze the rat serum and brain tissue samples for the drug e ffi-cacy evaluation of gross saponin of Tribulus terrestris L.fruit(GSTTF)against middle cerebral artery occlusion(MCAO)-induced ischemic stroke.This method has extensive practicability and great potential in the detection of FA,especially for the analysis of samples with complex matrices.
基金supported financially by the National Natural Science Foundation of China(Nos.91961125 and 22002085)supported by the“Fundamental Research Funds for the Central Universities”(No.2018JBZ107)+4 种基金Guangdong Basic and Applied Basic Research Foundation(No.2020A1515110832)“Key Program for International S&T Cooperation Projects of China”from the Ministry of Science and Technology of China(No.2018YFE0124600)Chemistry and Chemical Engineering Guangdong Laboratory(No.1932004)Science and Technology Project of Guangdong Province(No.2020B0101370001)the Project from China Petrochemical Corporation(No.S20L00151).
文摘Designing catalyst to achieve ammonia synthesis at mild conditions is a meaningful challenge in catalysis community.Defective g-C_(3)N_(4)nanosheet supported single-cluster ruthenium and iron catalysts were investigated for their ammonia synthesis performance.Based on density functional theory(DFT)calculations and microkinetic simulations,Ru_(3)single-cluster anchored on defective g-C3N4 nanosheet(Ru_(3)/Nv-g-C_(3)N_(4))has a turnover frequency(TOF)5.8 times higher than the Ru(0001)step surface at industrial reaction conditions of 673 K and 100 bar for ammonia synthesis.In other words,similar TOFs could be achieved on Ru_(3)/Nv-g-C_(3)N_(4)at much milder conditions(623 K,30 bar)than on Ru(0001)(673 K,100 bar).Our computations reveal the reaction proceeds parallelly on Ru_(3)/Nv-g-C_(3)N_(4)through both dissociative and alternative associative mechanisms at typical reaction conditions(600–700 K,10–100 bar);N–N bond cleavage of*N2 and*NNH from the two respective pathways controls the reaction collectively.With increasing temperatures or decreasing pressures,the dissociative mechanism gradually prevails and associative mechanism recedes.In comparison,Fe_(3)/Nv-g-C_(3)N_(4)catalyst shows a much lower catalytic activity than Ru3/Nv-g-C_(3)N_(4)by two orders of magnitude and the reaction occurs solely through the dissociative pathway.The finding provides a prospective candidate and deepens the mechanistic understanding for ammonia synthesis catalyzed by single-cluster catalysts(SCCs).
文摘Approximate analytical expressions of overall effectiveness factors for parallel catalytic reac-tions occurring in a spherical catalyst pellet with both internal and external mass transfer resistancesare obtained after taking the information given by asymptotic solutions valid for small and largevalues of Thiele moduli.This approximate procedure is feasible for power law as well asLangmuir-Hinshelwood kinetics and the agreement between the approximation and the numerical re-sults is good enough for practical purposes.Moreover,the method does not require any iterative ortrial-and-error computation,and can be conveniently applied in most practical calculations for reac-tors giving reliable results.
基金supported by Heilongjiang Provincial Natural Science Foundation of China(Grant No.YQ2022C012)China Postdoctoral Science Foundation(Grant No.2022MD713728)+1 种基金Heilongjiang Provincial Postdoctoral Fund(Grant No.LBHZ21046)the Open Project of Key Laboratory of Biology and Genetic Improvement of Horticultural Crops(Northeast Region),Ministry of Agriculture and Rural Affairs,and National Key Research and Development Program of China(Grant No.2023YFD1201501).
文摘Ogura cytoplasmic male sterility(Ogura CMS)is extensively applied in hybrid seed production in cruciferous crops.However,the posttranscriptional molecular basis of Ogura CMS in cruciferous crops remains elusive.Here,a data-independent acquisition-based proteomic approach coupled with a parallel reaction monitoring-based targeted proteomic assay was used to analyze the proteome dynamics of Ogura CMS cabbage line RM and its maintainer line RF during floral bud development to obtain insights into the mechanism underlying Ogura CMS in cruciferous crops.A total of 9162 proteins corresponding to 61464 peptides were identified in RM and RF floral buds.The proteomic fluctuation of RM was weaker than that of RF.Differences in protein expression between RM and RF gradually enlarged with floral bud development.Fifteen continually up-regulated and eight continually down-regulated proteins were found in RM relative to RF throughout floral bud development.Differentially expressed proteins between RM and RF during floral bud development were implicated in the endoplasmic reticulum(ER)-associated protein processing pathway,in which most of them exhibited down-regulated expression in RM.These data suggest that ER-associated protein processing may be involved in pollen abortion in Ogura CMS cabbage by inhibiting the expression of critical factors.Our findings not only deepen the understanding of the molecular mechanisms of Ogura CMS in cruciferous crops but also provide better guidance for applying Ogura CMS in the hybrid breeding of cruciferous crops.
文摘Dialkylamino-4(3H)-quinazolinones 4 were rapidly synthesized by a solution-phase parallel synthetic method, which includes aza-Wittig reaction of iminophosphorane 1 with aromatic isocynate to give carbodiimide 2 and subsequent reaction of 2 with various aliphatic secondary amine in a parallel fashion.
基金Supported by National Key Development Plan for Precision Medicine Research,No.2017YFC0910002。
文摘BACKGROUND Colorectal cancer(CRC)is the second leading cause of cancer-related death,with high morbidity worldwide.There is an urgent need to find reliable diagnostic biomarkers of CRC and explore the underlying molecular mechanisms.Exosomes are involved in intercellular communication and participate in multiple pathological processes,serving as an important part of the tumor microenvironment.AIM To investigate the proteomic characteristics of CRC tumor-derived exosomes and to identify candidate exosomal protein markers for CRC.METHODS In this study,10 patients over 50 years old who were diagnosed with moderately differentiated adenocarcinoma were recruited.We paired CRC tissues and adjacent normal intestinal tissues(>5 cm)to form the experimental and control groups.Purified exosomes were extracted separately from each tissue sample.Data-independent acquisition mass spectrometry was implemented in 8 matched samples of exosomes to explore the proteomic expression profiles,and differentially expressed proteins(DEPs)were screened by bioinformatics analysis.Promising exosomal proteins were verified using parallel reaction monitoring(PRM)analysis in 10 matched exosome samples.RESULTS A total of 1393 proteins were identified in the CRC tissue group,1304 proteins were identified in the adjacent tissue group,and 283 proteins were significantly differentially expressed between them.Enrichment analysis revealed that DEPs were involved in multiple biological processes related to cytoskeleton construction,cell movement and migration,immune response,tumor growth and telomere metabolism,as well as ECM-receptor interaction,focal adhesion and mTOR signaling pathways.Six differentially expressed exosomal proteins(NHP2,OLFM4,TOP1,SAMP,TAGL and TRIM28)were validated by PRM analysis and evaluated by receiver operating characteristic curve(ROC)analysis.The area under the ROC curve was 0.93,0.96,0.97,0.78,0.75,and 0.88(P<0.05)for NHP2,OLFM4,TOP1,SAMP,TAGL,and TRIM28,respectively,indicating their good ability to distinguish CRC tissues from adjacent intestinal tissues.CONCLUSION In our study,comprehensive proteomic profiles were obtained for CRC tissue exosomes.Six exosomal proteins,NHP2,OLFM4,TOP1,SAMP,TAGL and TRIM28,may be promising diagnostic markers and effective therapeutic targets for CRC,but further experimental investigation is needed.
