The binding of Co (phen)2dppz3+ to calf thymus DNA,as investigated using absorption spectroscopy. viscosity and electrophoresis measurements,here dppz is dipyrido[3, 2-a: 2'3'-c]phenazine. The compound shows a...The binding of Co (phen)2dppz3+ to calf thymus DNA,as investigated using absorption spectroscopy. viscosity and electrophoresis measurements,here dppz is dipyrido[3, 2-a: 2'3'-c]phenazine. The compound shows absorption hypochromicity and the specific viscosity increased upon binding to calf thymus DNA The complex is also shown to be more efficient photosensitisers for single strand breaks in plasmid DNA展开更多
In order to analyze the complex chemical kinetic mechanism systematically and find out the redundant species and reactions, a numerical platform for mechanism analysis and simplification is established basing on Path ...In order to analyze the complex chemical kinetic mechanism systematically and find out the redundant species and reactions, a numerical platform for mechanism analysis and simplification is established basing on Path Flux Analysis （PFA）. It is used to reduce a detailed mechanism for flame inhibited by phosphorus containing compounds, a reduced mechanism with 65 species and 335 reactions is obtained. The detailed and reduced mechanism are both used to calculate the freely-propagating premix C3H8/air flame with different dimethyl methylphosphonate doped over a wide range of equivalence ratios. The concentration distributions of free radicals and major species are compared, and the results under two different mechanisms agree well. The laminar flame speed obtained by the two mechanisms also matches well, with the maximum relative error introduces as a small value of 1.7%. On the basis of the reduced mechanism validation, the correlativity analysis is conducted between flame speed and flee radical concentrations, which can provide information for target species selection in the further mechanism reduction. By analyzing the species and reactions fluxes, the species and reaction paths which contribute the flame inhibition significantly are determined.展开更多
Nitrogen-rich heterocyclic energetic compounds(NRHECs)and their salts have witnessed widespread synthesis in recent years.The substantial energy-density content within these compounds can lead to potentially dangerous...Nitrogen-rich heterocyclic energetic compounds(NRHECs)and their salts have witnessed widespread synthesis in recent years.The substantial energy-density content within these compounds can lead to potentially dangerous explosive reactions when subjected to external stimuli such as electrical discharge.Therefore,developing a reliable model for predicting their electrostatic discharge sensitivity(ESD)becomes imperative.This study proposes a novel and straightforward model based on the presence of specific groups(-NH_(2) or-NH-,-N=N^(+)-O^(-)and-NNO_(2),-ONO_(2) or-NO_(2))under certain conditions to assess the ESD of NRHECs and their salts,employing interpretable structural parameters.Utilizing a comprehensive dataset comprising 54 ESD measurements of NRHECs and their salts,divided into 49/5 training/test sets,the model achieves promising results.The Root Mean Square Error(RMSE),Mean Absolute Error(MAE),and Maximum Error for the training set are reported as 0.16 J,0.12 J,and 0.5 J,respectively.Notably,the ratios RMSE(training)/RMSE(test),MAE(training)/MAE(test),and Max Error(training)/Max Error(test)are all greater than 1.0,indicating the robust predictive capabilities of the model.The presented model demonstrates its efficacy in providing a reliable assessment of ESD for the targeted NRHECs and their salts,without the need for intricate computer codes or expert involvement.展开更多
Oxygen-isotopic labelings play important roles in identifying and understanding chemical and biological processes.Direct C=O to C=^(18)O or C=^(17)O conversion in a single step leading to labeled compounds can allevia...Oxygen-isotopic labelings play important roles in identifying and understanding chemical and biological processes.Direct C=O to C=^(18)O or C=^(17)O conversion in a single step leading to labeled compounds can alleviate synthetic burdens without the need for resynthesis.Here we describe a photocatalytic oxygenisotopic labeling protocol that can efficiently and selectively install ^(18)O and ^(17)O on carbonyls of ketones and aldehydes via oxygen isotope exchange with oxygen-isotopic waters(H_(2)^(18)O or H_(2)^(17)O)as the sources of oxygen isotopes,in which light and oxygen-enabled sodium alkanesulfinates catalyzed this process.This strategy was extended to the in-situ formed ketones from the photocatalytic aerobic oxidation of alkyl arenes and secondary alcohols.Furthermore,reduction of the oxygen-isotopically labeled aldehydes with NaBH_(4) provided the corresponding oxygen-isotopically labeled primary alcohols.We believe that the oxygen-isotopically labeling method will be widely used in chemistry,biology and medicine fields.展开更多
Objective： To explore the pharmacologic effects of Chinese medicine Bushen Huayu Jiedu Compound Recipe （补肾化瘀解毒复方,BSHYJDR） in drug-resistance cells of lung cancer. Methods： Human lung adenocarcinoma A549/DD...Objective： To explore the pharmacologic effects of Chinese medicine Bushen Huayu Jiedu Compound Recipe （补肾化瘀解毒复方,BSHYJDR） in drug-resistance cells of lung cancer. Methods： Human lung adenocarcinoma A549/DDP cell strain was selected, serum pharmacology and flow cytometer （FCM） method were adopted, $180 tumor-bearing mice and normal mice were given, through gastrogavage, different doses of a decocted concentration of BSHYJDR. Serum from the abdominal aorta was taken to observe the effect of drug-serum on cisplatin （DDP） concentration, free Ca^2＋ concentration and the expression of lung drug-resistance protein LRP-56 in A549/DDP cells. Results： Compared with the drug-resistance group, the intracellular DDP concentration in the group taking a high dose and the normal group of Chinese medicine showed significant difference （P〈0.05）, while no significant difference was found in the low-dose group （P〉0.05）. Compared with the drug-resistance group, the Ca^2＋ concentration in cells and the expression of LRP in lung cancer drug-resistance cells A549/DDP of the high-dose group, the low-dose group and the normal group of Chinese medicine were significantly different （all P〈0.01）, the LRP expression of the normal group was obviously higher than that of the drug-resistance group （P〈0.05）. Cenclusien： It was indicated that serum containing Chinese medicine BSHYJDR in the tumor-bearing mice and the normal mice had certainly different, tumor-bearing mice serum containing could improve drug concentration in lung cancer drug-resistance cells, prevent the inflow and release of Ca^2＋, and inhibit the expression of the drug-resistance gene in the lung cancer drug-resistance cells, which might be the mechanism of BSHYJDR in enhancing the efficacy in reversing and inhibiting tumor.展开更多
文摘The binding of Co (phen)2dppz3+ to calf thymus DNA,as investigated using absorption spectroscopy. viscosity and electrophoresis measurements,here dppz is dipyrido[3, 2-a: 2'3'-c]phenazine. The compound shows absorption hypochromicity and the specific viscosity increased upon binding to calf thymus DNA The complex is also shown to be more efficient photosensitisers for single strand breaks in plasmid DNA
基金Supported by the National Natural Science Foundation of China （51176181）, the National Basic Research Program of China （2012CB719704）, and the Research Fund for the Doctoral Program of Higher Education （20123402110047）.
文摘In order to analyze the complex chemical kinetic mechanism systematically and find out the redundant species and reactions, a numerical platform for mechanism analysis and simplification is established basing on Path Flux Analysis （PFA）. It is used to reduce a detailed mechanism for flame inhibited by phosphorus containing compounds, a reduced mechanism with 65 species and 335 reactions is obtained. The detailed and reduced mechanism are both used to calculate the freely-propagating premix C3H8/air flame with different dimethyl methylphosphonate doped over a wide range of equivalence ratios. The concentration distributions of free radicals and major species are compared, and the results under two different mechanisms agree well. The laminar flame speed obtained by the two mechanisms also matches well, with the maximum relative error introduces as a small value of 1.7%. On the basis of the reduced mechanism validation, the correlativity analysis is conducted between flame speed and flee radical concentrations, which can provide information for target species selection in the further mechanism reduction. By analyzing the species and reactions fluxes, the species and reaction paths which contribute the flame inhibition significantly are determined.
文摘Nitrogen-rich heterocyclic energetic compounds(NRHECs)and their salts have witnessed widespread synthesis in recent years.The substantial energy-density content within these compounds can lead to potentially dangerous explosive reactions when subjected to external stimuli such as electrical discharge.Therefore,developing a reliable model for predicting their electrostatic discharge sensitivity(ESD)becomes imperative.This study proposes a novel and straightforward model based on the presence of specific groups(-NH_(2) or-NH-,-N=N^(+)-O^(-)and-NNO_(2),-ONO_(2) or-NO_(2))under certain conditions to assess the ESD of NRHECs and their salts,employing interpretable structural parameters.Utilizing a comprehensive dataset comprising 54 ESD measurements of NRHECs and their salts,divided into 49/5 training/test sets,the model achieves promising results.The Root Mean Square Error(RMSE),Mean Absolute Error(MAE),and Maximum Error for the training set are reported as 0.16 J,0.12 J,and 0.5 J,respectively.Notably,the ratios RMSE(training)/RMSE(test),MAE(training)/MAE(test),and Max Error(training)/Max Error(test)are all greater than 1.0,indicating the robust predictive capabilities of the model.The presented model demonstrates its efficacy in providing a reliable assessment of ESD for the targeted NRHECs and their salts,without the need for intricate computer codes or expert involvement.
基金supported by Natural Science Foundation of Beijing Municipality(No.2222011)National Natural Science Foundation of China(No.22077074)China Postdoctoral Science Foundation(No.2021M701869).
文摘Oxygen-isotopic labelings play important roles in identifying and understanding chemical and biological processes.Direct C=O to C=^(18)O or C=^(17)O conversion in a single step leading to labeled compounds can alleviate synthetic burdens without the need for resynthesis.Here we describe a photocatalytic oxygenisotopic labeling protocol that can efficiently and selectively install ^(18)O and ^(17)O on carbonyls of ketones and aldehydes via oxygen isotope exchange with oxygen-isotopic waters(H_(2)^(18)O or H_(2)^(17)O)as the sources of oxygen isotopes,in which light and oxygen-enabled sodium alkanesulfinates catalyzed this process.This strategy was extended to the in-situ formed ketones from the photocatalytic aerobic oxidation of alkyl arenes and secondary alcohols.Furthermore,reduction of the oxygen-isotopically labeled aldehydes with NaBH_(4) provided the corresponding oxygen-isotopically labeled primary alcohols.We believe that the oxygen-isotopically labeling method will be widely used in chemistry,biology and medicine fields.
基金Supported by Post-Doctoral Foundation of China,(2001)5,Guangdong Province Technology Project(No.73062)
文摘Objective： To explore the pharmacologic effects of Chinese medicine Bushen Huayu Jiedu Compound Recipe （补肾化瘀解毒复方,BSHYJDR） in drug-resistance cells of lung cancer. Methods： Human lung adenocarcinoma A549/DDP cell strain was selected, serum pharmacology and flow cytometer （FCM） method were adopted, $180 tumor-bearing mice and normal mice were given, through gastrogavage, different doses of a decocted concentration of BSHYJDR. Serum from the abdominal aorta was taken to observe the effect of drug-serum on cisplatin （DDP） concentration, free Ca^2＋ concentration and the expression of lung drug-resistance protein LRP-56 in A549/DDP cells. Results： Compared with the drug-resistance group, the intracellular DDP concentration in the group taking a high dose and the normal group of Chinese medicine showed significant difference （P〈0.05）, while no significant difference was found in the low-dose group （P〉0.05）. Compared with the drug-resistance group, the Ca^2＋ concentration in cells and the expression of LRP in lung cancer drug-resistance cells A549/DDP of the high-dose group, the low-dose group and the normal group of Chinese medicine were significantly different （all P〈0.01）, the LRP expression of the normal group was obviously higher than that of the drug-resistance group （P〈0.05）. Cenclusien： It was indicated that serum containing Chinese medicine BSHYJDR in the tumor-bearing mice and the normal mice had certainly different, tumor-bearing mice serum containing could improve drug concentration in lung cancer drug-resistance cells, prevent the inflow and release of Ca^2＋, and inhibit the expression of the drug-resistance gene in the lung cancer drug-resistance cells, which might be the mechanism of BSHYJDR in enhancing the efficacy in reversing and inhibiting tumor.
