The effects of bile salts （sodium cholate and sodium deoxycholate, 0-20 mmol/L）, divalent cations （Ca^2＋, Mg^2＋, Cu^2＋ and Zn^2＋, 0-20 mmol/L） or pH （3.0-10.0） on the adsorption of norfloxacin by three selec...The effects of bile salts （sodium cholate and sodium deoxycholate, 0-20 mmol/L）, divalent cations （Ca^2＋, Mg^2＋, Cu^2＋ and Zn^2＋, 0-20 mmol/L） or pH （3.0-10.0） on the adsorption of norfloxacin by three selected soils （Paddy_H, Paddy_G and Red_J） were systematically studied. Soil adsorption of norfloxacin follows a pseudo second-order kinetics model, and the maximum adsorption capacity has been determined from the nonlinear fit of the Langmuir isotherm model to be 88.8, 88.1 and 63.0 μmol/g for the adsorption onto Paddy_H, Paddy_G and Red_J, respectively. The results indicate that norfloxacin has a high adsorption affinity for the agricultural soils tested and that the organic content of these soils have at least a slight influence on this adsorption. The adsorption of norfloxacin to soils was strongly dependent on pH and exhibited a maximum at approximately pH 6. The presence of divalent cations prominently suppressed the adsorption of norfloxacin by paddy soils, which followed an order of Cu^2＋ 〉 Mg^2＋ 〉 Ca^2＋ 〉 Zn^2＋, and by red soil, which followed an order of Cu^2＋ 〉 Zn^2＋ 〉 Ca^2＋ 〉 Mg^2＋. The adsorption of norfloxacin （by the soils studied） sharply decreased as the amount of bile salts was increased. For uncharged norfloxacin at environmentally relevant pH values, such factors as soil type, exogenous divalent cations and macromolecules significantly altered the environmental fate and transport of norfloxacin between aquatic and soil interfaces.展开更多
Monocyclic nitrogen-rich 3-(aminomethyl)-4,5-diamine-1,2,4-triazole(1)and fused cyclic 3,7-diamine-6-(aminomethyl)-[1,2,4]triazolo[4,3-b][1,2,4]triazole(9)were synthesized through the convenient cyclization reaction f...Monocyclic nitrogen-rich 3-(aminomethyl)-4,5-diamine-1,2,4-triazole(1)and fused cyclic 3,7-diamine-6-(aminomethyl)-[1,2,4]triazolo[4,3-b][1,2,4]triazole(9)were synthesized through the convenient cyclization reaction from the readily available reactant.Their energetic salts with high nitrogen content were proved to be rare examples of divalent monocyclic/fused cyclic cationic salts according to the single crystal analyses.The structure of intermediate B was also identified and verified by its trivalent cation crystal 17.5H_2O indirectly.Energetic compounds 2-8 and 10-17 were fully characterized by NMR spectroscopy,infrared spectroscopy,differential scanning calorimetry,elemental analysis.These energetic salts exhibit good thermal stability with decomposition temperatures ranged from 182℃to 245℃.The sensitivity of compounds 2,6,10 and 14 is similar or superior to that of RDX while the others were much more insensitive to mechanical stimulate.Furthermore,detonation velocity of 10(8843 m/s)surpass that of RDX(D=8795 m/s).Considering the high gas production volume(≥808 L/kg)of 2,4,10and 12,constant-volume combustion experiments were conduct to evaluate their gas production capacities specifically.These compounds possess much higher maximum gas-production pressures(P_(max):7.88-10.08 MPa)than the commonly used reagent guanidine nitrate(GN:P_(max)=4.20 MPa),which indicate their strong gas production capacity.展开更多
Potential toxicity of transition metals like Hg, Cu and Cd are well known and their affinity toward proteins is of great concern. This work explores the selective nature of interactions of Cu2＋, Hg2＋ and Cd2＋ with ...Potential toxicity of transition metals like Hg, Cu and Cd are well known and their affinity toward proteins is of great concern. This work explores the selective nature of interactions of Cu2＋, Hg2＋ and Cd2＋ with the heme proteins leghemoglobin, myoglobin and cytochrome C. The binding profiles were analyzed using absorbance spectrum and steady-state fluorescence spectroscopy. Thermodynamic parameters like enthalpy, entropy and free energy changes were derived by isothermal calorimetry and consequent binding parameters were compared for these heme proteins. Free energy （AG） values revealed Cu2＋ binding toward myoglobin and leghemoglobin to be specific and facile in contrast to weak binding for Hg2＋ or Cd2＋ . Time correlated single photon counting indicated significant alteration in excited state lifetimes for metal complexed myoglobin and leghemoglobin suggesting bimolecular collisions to be involved. Interestingly, none of these cations showed significant affinity for cytochrome c pointing that, presence of conserved sequences or heme group is not the only criteria for cation binding toward heme proteins, but the microenvironment of the residues or a specific folding pattern may be responsible for these differential conjugation profile. Binding of these cations may modulate the conformation and functions of these biologically important proteins.展开更多
Recently,lipid nanoparticles(LNPs)have been extensively investigated as non-viral carriers of nucleic acid vaccines due to their high transport efficiency,safety,and straightforward production and scalability.However,...Recently,lipid nanoparticles(LNPs)have been extensively investigated as non-viral carriers of nucleic acid vaccines due to their high transport efficiency,safety,and straightforward production and scalability.However,the molecular mechanism underlying the interactions between nucleic acids and phospholipid bilayers within LNPs remains elusive.In this study,we employed the all-atom molecular dynamics simulation to investigate the interactions between single-stranded nucleic acids and a phospholipid bilayer.Our findings revealed that hydrophilic bases,specifically G in single-stranded RNA(ssRNA)and single-stranded DNA(ssDNA),displayed a higher propensity to form hydrogen bonds with phospholipid head groups.Notably,ssRNA exhibited stronger binding energy than ssDNA.Furthermore,divalent ions,particularly Ca2+,facilitated the binding of ssRNA to phospholipids due to their higher binding energy and lower dissociation rate from phospholipids.Overall,our study provides valuable insights into the molecular mechanisms underlying nucleic acidphospholipid interactions,with potential implications for the nucleic acids in biotherapies,particularly in the context of lipid carriers.展开更多
Pseudomonas aeruginosa recognized as opportunistic pathogen causes severe infections for hospitalized patients, survive in and resist many antimicrobial agents like antibiotics and disinfectants. The aim of this study...Pseudomonas aeruginosa recognized as opportunistic pathogen causes severe infections for hospitalized patients, survive in and resist many antimicrobial agents like antibiotics and disinfectants. The aim of this study is to evaluate the role of EDTA in improving the sensitivity of resistant P. aeruginosa strains to disinfectants and Na-citrate. The strains used in this study were selected in house from Tanta University hospital, Egypt and tested for the synergistic effect of EDTA with Na-citrate or disinfectant(s). The results showed a significant effect of EDTA in improving P. aeruginosa sensitivity. In conclusion, we proposed that using EDTA in combination with different sanitization compounds and antimicrobial agents especially in hospitals aiming to control the spreading of infections.展开更多
The divalent metal cations promote new bone formation through modulation of sensory and sympathetic nervous systems(SNS)activities.In addition,acetylcholine(Ach),as a chief neurotransmitter released by the parasympath...The divalent metal cations promote new bone formation through modulation of sensory and sympathetic nervous systems(SNS)activities.In addition,acetylcholine(Ach),as a chief neurotransmitter released by the parasympathetic nervous system(PNS),also affects bone remodeling,so it is of worth to investigate if the divalent cations influence PNS activity.Of note,these cations are key co-enzymes modulating glucose metabolism.Aerobic glycolysis rather than oxidative phosphorylation favors osteogenesis of mesenchymal stem cells(MSCs),so it is of interest to study the effects of these cations on glucose metabolic pathway.Prior to biological function assessment,the tolerance limits of the divalent metal cations(Mg^(2+),Zn^(2+),and Ca^(2+))and their combinations were profiled.In terms of direct effects,these divalent cations potentially enhanced migration and adhesion capability of MSCs through upregulating Tgf-β1 and Integrin-β1 levels.Interestingly,the divalent cations alone did not influence osteogenesis and aerobic glycolysis of undifferentiated MSCs.However,once the osteogenic differentiation of MSCs was initiated by neurotransmitters or osteogenic differentiation medium,the osteogenesis of MSCs could be significantly promoted by the divalent cations,which was accompanied by the improved aerobic glycolysis.In terms of indirect effects,the divalent cations significantly upregulated levels of sensory nerve derived CGRP,PNS produced choline acetyltransferase and type H vessels,while significantly tuned down sympathetic activity in the defect zone in rats,thereby contributing to significantly increased bone formation relative to the control group.Together,the divalent cations favor bone regeneration via modulation of sensory-autonomic nervous systems and promotion of aerobic glycolysis-driven osteogenesis of MSCs after osteogenic initiation by neurotransmitters.展开更多
基金supported by the National Natural Science Foundation of China(No.21207104)the Natural Science Foundation of Hubei Province(No.2011CDB274)+2 种基金the Youth Chenguang Project of Science and Technology of Wuhan City(No.2013070104010009)the Fundamental Research Funds for the Central Universities(No.121095)the Postdoctoral Science Foundation of China(No.2012 M511675)
文摘The effects of bile salts （sodium cholate and sodium deoxycholate, 0-20 mmol/L）, divalent cations （Ca^2＋, Mg^2＋, Cu^2＋ and Zn^2＋, 0-20 mmol/L） or pH （3.0-10.0） on the adsorption of norfloxacin by three selected soils （Paddy_H, Paddy_G and Red_J） were systematically studied. Soil adsorption of norfloxacin follows a pseudo second-order kinetics model, and the maximum adsorption capacity has been determined from the nonlinear fit of the Langmuir isotherm model to be 88.8, 88.1 and 63.0 μmol/g for the adsorption onto Paddy_H, Paddy_G and Red_J, respectively. The results indicate that norfloxacin has a high adsorption affinity for the agricultural soils tested and that the organic content of these soils have at least a slight influence on this adsorption. The adsorption of norfloxacin to soils was strongly dependent on pH and exhibited a maximum at approximately pH 6. The presence of divalent cations prominently suppressed the adsorption of norfloxacin by paddy soils, which followed an order of Cu^2＋ 〉 Mg^2＋ 〉 Ca^2＋ 〉 Zn^2＋, and by red soil, which followed an order of Cu^2＋ 〉 Zn^2＋ 〉 Ca^2＋ 〉 Mg^2＋. The adsorption of norfloxacin （by the soils studied） sharply decreased as the amount of bile salts was increased. For uncharged norfloxacin at environmentally relevant pH values, such factors as soil type, exogenous divalent cations and macromolecules significantly altered the environmental fate and transport of norfloxacin between aquatic and soil interfaces.
基金supported by the National Natural Science Foundation of China(No.21875110,22075143)the Science Challenge Project(No.TZ2018004)the Qing Lan Project for the grant。
文摘Monocyclic nitrogen-rich 3-(aminomethyl)-4,5-diamine-1,2,4-triazole(1)and fused cyclic 3,7-diamine-6-(aminomethyl)-[1,2,4]triazolo[4,3-b][1,2,4]triazole(9)were synthesized through the convenient cyclization reaction from the readily available reactant.Their energetic salts with high nitrogen content were proved to be rare examples of divalent monocyclic/fused cyclic cationic salts according to the single crystal analyses.The structure of intermediate B was also identified and verified by its trivalent cation crystal 17.5H_2O indirectly.Energetic compounds 2-8 and 10-17 were fully characterized by NMR spectroscopy,infrared spectroscopy,differential scanning calorimetry,elemental analysis.These energetic salts exhibit good thermal stability with decomposition temperatures ranged from 182℃to 245℃.The sensitivity of compounds 2,6,10 and 14 is similar or superior to that of RDX while the others were much more insensitive to mechanical stimulate.Furthermore,detonation velocity of 10(8843 m/s)surpass that of RDX(D=8795 m/s).Considering the high gas production volume(≥808 L/kg)of 2,4,10and 12,constant-volume combustion experiments were conduct to evaluate their gas production capacities specifically.These compounds possess much higher maximum gas-production pressures(P_(max):7.88-10.08 MPa)than the commonly used reagent guanidine nitrate(GN:P_(max)=4.20 MPa),which indicate their strong gas production capacity.
文摘Potential toxicity of transition metals like Hg, Cu and Cd are well known and their affinity toward proteins is of great concern. This work explores the selective nature of interactions of Cu2＋, Hg2＋ and Cd2＋ with the heme proteins leghemoglobin, myoglobin and cytochrome C. The binding profiles were analyzed using absorbance spectrum and steady-state fluorescence spectroscopy. Thermodynamic parameters like enthalpy, entropy and free energy changes were derived by isothermal calorimetry and consequent binding parameters were compared for these heme proteins. Free energy （AG） values revealed Cu2＋ binding toward myoglobin and leghemoglobin to be specific and facile in contrast to weak binding for Hg2＋ or Cd2＋ . Time correlated single photon counting indicated significant alteration in excited state lifetimes for metal complexed myoglobin and leghemoglobin suggesting bimolecular collisions to be involved. Interestingly, none of these cations showed significant affinity for cytochrome c pointing that, presence of conserved sequences or heme group is not the only criteria for cation binding toward heme proteins, but the microenvironment of the residues or a specific folding pattern may be responsible for these differential conjugation profile. Binding of these cations may modulate the conformation and functions of these biologically important proteins.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12222506,12347102,and 12174184).
文摘Recently,lipid nanoparticles(LNPs)have been extensively investigated as non-viral carriers of nucleic acid vaccines due to their high transport efficiency,safety,and straightforward production and scalability.However,the molecular mechanism underlying the interactions between nucleic acids and phospholipid bilayers within LNPs remains elusive.In this study,we employed the all-atom molecular dynamics simulation to investigate the interactions between single-stranded nucleic acids and a phospholipid bilayer.Our findings revealed that hydrophilic bases,specifically G in single-stranded RNA(ssRNA)and single-stranded DNA(ssDNA),displayed a higher propensity to form hydrogen bonds with phospholipid head groups.Notably,ssRNA exhibited stronger binding energy than ssDNA.Furthermore,divalent ions,particularly Ca2+,facilitated the binding of ssRNA to phospholipids due to their higher binding energy and lower dissociation rate from phospholipids.Overall,our study provides valuable insights into the molecular mechanisms underlying nucleic acidphospholipid interactions,with potential implications for the nucleic acids in biotherapies,particularly in the context of lipid carriers.
文摘Pseudomonas aeruginosa recognized as opportunistic pathogen causes severe infections for hospitalized patients, survive in and resist many antimicrobial agents like antibiotics and disinfectants. The aim of this study is to evaluate the role of EDTA in improving the sensitivity of resistant P. aeruginosa strains to disinfectants and Na-citrate. The strains used in this study were selected in house from Tanta University hospital, Egypt and tested for the synergistic effect of EDTA with Na-citrate or disinfectant(s). The results showed a significant effect of EDTA in improving P. aeruginosa sensitivity. In conclusion, we proposed that using EDTA in combination with different sanitization compounds and antimicrobial agents especially in hospitals aiming to control the spreading of infections.
基金supported by the National Natural Science Foundation of China(Grant Nos.:32271381,32471378 and 81971760)the Science and Technology Innovation Commission of Shenzhen(Grant No.:JCYJ20220530145601004)+4 种基金Guangdong Basic and Applied Basic Research Foundation(Grant No.:2024A1515010311)Dalian Medical Science Research Project(Grant NO.:2111038)State Key R&D Program(Grant NO.:2020JH2/10300093)Liaoning Provincial Department of Education Key Research Project(Grant NO.:LJKZZ20220148)Liaoning Provincial Health Commission,"Xingliao Plan of Excellence"Medical Masters Program(Grant NO.:YXMJ-QN-21).
文摘The divalent metal cations promote new bone formation through modulation of sensory and sympathetic nervous systems(SNS)activities.In addition,acetylcholine(Ach),as a chief neurotransmitter released by the parasympathetic nervous system(PNS),also affects bone remodeling,so it is of worth to investigate if the divalent cations influence PNS activity.Of note,these cations are key co-enzymes modulating glucose metabolism.Aerobic glycolysis rather than oxidative phosphorylation favors osteogenesis of mesenchymal stem cells(MSCs),so it is of interest to study the effects of these cations on glucose metabolic pathway.Prior to biological function assessment,the tolerance limits of the divalent metal cations(Mg^(2+),Zn^(2+),and Ca^(2+))and their combinations were profiled.In terms of direct effects,these divalent cations potentially enhanced migration and adhesion capability of MSCs through upregulating Tgf-β1 and Integrin-β1 levels.Interestingly,the divalent cations alone did not influence osteogenesis and aerobic glycolysis of undifferentiated MSCs.However,once the osteogenic differentiation of MSCs was initiated by neurotransmitters or osteogenic differentiation medium,the osteogenesis of MSCs could be significantly promoted by the divalent cations,which was accompanied by the improved aerobic glycolysis.In terms of indirect effects,the divalent cations significantly upregulated levels of sensory nerve derived CGRP,PNS produced choline acetyltransferase and type H vessels,while significantly tuned down sympathetic activity in the defect zone in rats,thereby contributing to significantly increased bone formation relative to the control group.Together,the divalent cations favor bone regeneration via modulation of sensory-autonomic nervous systems and promotion of aerobic glycolysis-driven osteogenesis of MSCs after osteogenic initiation by neurotransmitters.
