ZnO nanoorystals thin film were prepared by means of the self-assembly mothed. The complex films of mercaptoacetic acid(MPA) and ZnO nanocrystals(ZNCs) were prepared by means of the self-assembly technique. The intera...ZnO nanoorystals thin film were prepared by means of the self-assembly mothed. The complex films of mercaptoacetic acid(MPA) and ZnO nanocrystals(ZNCs) were prepared by means of the self-assembly technique. The interaction between the MPA and ZnO within the MPA and ZnO nanocrystal thin film decreases the photoluminescence intensity of the ZnO. The interaction was manifested by the X-ray photoelectron spectra. The intensity change of the photoluminescence of the ZnO is discussed on the basis of taking into account the process of electron transfer on the interface between the ZnO and MPA. The electron transfer of ZnO depends on the distance between the ZnO and MPA.展开更多
Mesoporous MCM-41 supported Schiff base and Cu SO4· 5H2 O shows high catalytic activity in the cyclocondensation of mercaptoacetic acid with imines（or aldehydes and amines） to afford pharmaceutically important ...Mesoporous MCM-41 supported Schiff base and Cu SO4· 5H2 O shows high catalytic activity in the cyclocondensation of mercaptoacetic acid with imines（or aldehydes and amines） to afford pharmaceutically important thiazolidinone derivatives. The catalytic reactions involving twocomponents or three-components afforded the desired product in high yields（up to 98% and 99%）.Moreover, the catalyst works well with respect to recyclability, giving the product in 85% and 83% yields after recycling six times.展开更多
Interfacial proton transfer reactions of pure mercaptoacetic acid (MA) and 2-mercaptobenzothiazole (Mbz) mixed self-assembled monolayers (SAMs) have been studied using a.c. impedance titration method. The charge-trans...Interfacial proton transfer reactions of pure mercaptoacetic acid (MA) and 2-mercaptobenzothiazole (Mbz) mixed self-assembled monolayers (SAMs) have been studied using a.c. impedance titration method. The charge-transfer resistance (Rct,) is measured with the monolayer composition and the ionic strength of pH solution. The surface pKa can be obtained by the plots of Rct and pH, the reasons of shifts of surface pKa are also explained.展开更多
A ultra-sensitive,highly specific,real-time polymerase chain reaction system based on mercaptoacetic acid-modified CdTe nanocrystals(mQDs)is reported.With the addition of 3 nm mQDs into the PCR reagent,the photolumine...A ultra-sensitive,highly specific,real-time polymerase chain reaction system based on mercaptoacetic acid-modified CdTe nanocrystals(mQDs)is reported.With the addition of 3 nm mQDs into the PCR reagent,the photoluminescent(PL)intensities of mQDs decreased gradually as the DNA templates and PCR cycles increased,in an approximate negative linear relation to the DNA concentration logarithm or cycles,the PL peaks exhibited red-shifts synchronously.Mg2+ions decreased the PL intensity of mQDs in a dose-dependent means,and Taq DNA polymerase enhanced the PL intensity of mQDs in a dose-dependent means.Real-time PCR based on mQDs showed an increased sensitivity at least 103 fold higher than that based on SYBR Green I.The specificity of PCR was enhanced in the PCR reagent with less than 1.33mg/mL mQDs.The potential mechanism is also discussed.This novel PCR system based on mQDs has great potential in applications such as ultra-sensitive specific DNA or RNA detection,dynamic molecular imaging,and photoelectric biosensors.展开更多
Impedance titration was used to determine the surface dissociation characteristics of short-chain carboxyl mercaptan self-assembled monolayers （SAMs）. Based on the change of the cyclic voltammetric peak current and ...Impedance titration was used to determine the surface dissociation characteristics of short-chain carboxyl mercaptan self-assembled monolayers （SAMs）. Based on the change of the cyclic voltammetric peak current and the charge-transfer resistance, which was related to pH value of the solution, the surface pKa of mercaptoacetic acid（MA）, 3-mercaptopropionic acid（MPA） and ω-mercaptohexanic acid（MHA） self-assembled membranes, with ionic strength being 0.1 mol/L, were determined to be 5.20, 4.80, 7.40, respectively. In addition, factors such as time needed for assembling, structure of monolayers and ionic strength, which effected the surface pKa, were studied as well. Such surface pKa shifts were sufficiently explained by interactions between interfacial molecules and hydrophobicity.展开更多
In a search for new antimicrobial agents, some new spiro[indol-thiazolidon- 2,4-diones] (6a-c) were synthesized by condensation of 5-substituted isatins 1 with sulfanilamide in MeOH, followed by aroylation with p-nitr...In a search for new antimicrobial agents, some new spiro[indol-thiazolidon- 2,4-diones] (6a-c) were synthesized by condensation of 5-substituted isatins 1 with sulfanilamide in MeOH, followed by aroylation with p-nitrobenzoyl chloride in DMF to get compounds 4a-c. Cycloaddition of 4a-c with thioglycolic acid in a dry non-polar solvent (dioxane) gave the targets 6a-c. Also, bis(5-fluorospiro[indoline-3,2’-thiazolidine]-2,4’-dione) (9) was synthesized by condensation of 5-fluoroindoline-2,3-dione with benzene-1,4-diamine (2:1 by mol) in MeOH, which followed by cycloaddition with thioglycolic acid in dioxane gave compound 8. Acylation of the later with 2,2,2-trifluoroacetic anhydride in THF has yielded the target 9. Structures of the products have been deduced from their elemental analysis and spectral data. The in vitro antimicrobial activity of the new systems 6a-c, and 9 was tested.展开更多
Objective: Increasing the emergence of Metallo-β-lactamase (MBL) producing gram-negative bacteria and their dexterous horizontal transmission demands rapid and accurate detection. This study was conducted to determin...Objective: Increasing the emergence of Metallo-β-lactamase (MBL) producing gram-negative bacteria and their dexterous horizontal transmission demands rapid and accurate detection. This study was conducted to determine a suitable method to promptly detect MBL-producing gram-negative bacteria. Methods: A total of 103 gram-negative bacteria were identified from various clinical samples at a tertiary care hospital in Dhaka city. MBL producers were detected by two phenotypic methods, the Disk Potentiation Test (DPT) and the Double Disk Synergy Test (DDST) based on β-lactam chelator combinations where EDTA/SMA has been used as an inhibitor and Imipenem, Ceftazidime as substrates. Results: 103 isolates which were identified as Escherichia coli spp, Klebsiella spp, Pseudomonas spp, Acinetobacter spp, Proteus spp, Providencia spp were found to be multidrug-resistant in antibiogram test. Isolates showed complete resistance (100%) to Imipenem, Meropenem, and Amoxiclav. The highest carbapenem-resistant etiological agents were Acinetobacter spp 40 (38.8%) followed by Pseudomonas spp 27 (26.2%), Klebsiella spp 26 (25.2%), Escherichia coli 8 (7.8%), Proteus spp 1 (1%) and Providencia spp 1 (1%). DPT method detected significantly (p = 0.000009) a higher number of MBL-producers (Imipenem with 0.5 M EDTA n = 61, 59.2% & Ceftazidime with 0.5 M EDTA n = 56, 54.4%) compared to the DDST method (Imipenem -0.5 M EDTA n = 43, 41.7%, Imipenem – SMA n = 38, 36.9% & Ceftazidime -0.5 M EDTA n = 15, 14.6%). Conclusion: Pieces of evidence suggest that DPT is a more sensitive method than DDST and could be recommended for identifying MBL-producing bacteria in Bangladeshi hospitals for the proper management of patients, to reduce time constraints and treatment costs.展开更多
The precursor of ZnO has been prepared by refluxing in ethanol at 70°C for 4 h using ZnAc2·H2O as the initial agent. Then ZnO has been prepared from the reaction of LiOH·H2O and the precursor. The ZnO i...The precursor of ZnO has been prepared by refluxing in ethanol at 70°C for 4 h using ZnAc2·H2O as the initial agent. Then ZnO has been prepared from the reaction of LiOH·H2O and the precursor. The ZnO is modified by mercaptoacetic acid (MAA) and detected by SEM and XRD. These ZnO particles have single phase, like-sphere and size of 4.6 nm. The modified effectivity of MAA for the quantum dots (QDs) has been investigated with UV-visible and fluorescence analysis, and the mechanism and property of ZnO light emitting have been discussed under given conditions. The reasons why the fluorescent emission peak of surface defects disappear and the exciton emission peak increase are that MAA effectively covers the surface defects of ZnO and stably coats ZnO particles. At the same time, the effect of the added amount of the MAA, temperature and electrolyte on light-emitting properties of modified product has also been studied. The result shows that the modified ZnO QDs have good fluorescence property, stability and suitable capability of resisting electrolyte. These results are important for biological analysis.展开更多
文摘ZnO nanoorystals thin film were prepared by means of the self-assembly mothed. The complex films of mercaptoacetic acid(MPA) and ZnO nanocrystals(ZNCs) were prepared by means of the self-assembly technique. The interaction between the MPA and ZnO within the MPA and ZnO nanocrystal thin film decreases the photoluminescence intensity of the ZnO. The interaction was manifested by the X-ray photoelectron spectra. The intensity change of the photoluminescence of the ZnO is discussed on the basis of taking into account the process of electron transfer on the interface between the ZnO and MPA. The electron transfer of ZnO depends on the distance between the ZnO and MPA.
基金the National Natural Science Foundation of China(Nos.21162026,21262034 and 21362036)Doctoral Fund of Xinjiang University(No.BS110111)for financial support,Xinjiang University Analytical&Testing Center for instrumental analyses,and Adamas-beta Chemical Co.,for all chemical reagents
文摘Mesoporous MCM-41 supported Schiff base and Cu SO4· 5H2 O shows high catalytic activity in the cyclocondensation of mercaptoacetic acid with imines（or aldehydes and amines） to afford pharmaceutically important thiazolidinone derivatives. The catalytic reactions involving twocomponents or three-components afforded the desired product in high yields（up to 98% and 99%）.Moreover, the catalyst works well with respect to recyclability, giving the product in 85% and 83% yields after recycling six times.
文摘Interfacial proton transfer reactions of pure mercaptoacetic acid (MA) and 2-mercaptobenzothiazole (Mbz) mixed self-assembled monolayers (SAMs) have been studied using a.c. impedance titration method. The charge-transfer resistance (Rct,) is measured with the monolayer composition and the ionic strength of pH solution. The surface pKa can be obtained by the plots of Rct and pH, the reasons of shifts of surface pKa are also explained.
基金supported by the National Natural Science Foundation of China(No.20803040 and No.20471599)Chinese 973 Project(2010CB933901),863 Key Project(2007AA022004)+2 种基金New Century Excellent Talent of Ministry of Education of China(NCET-08-0350)Special Infection Diseases Key Project of China(2009ZX10004-311)Shanghai Science and Technology Fund(10XD1406100).
文摘A ultra-sensitive,highly specific,real-time polymerase chain reaction system based on mercaptoacetic acid-modified CdTe nanocrystals(mQDs)is reported.With the addition of 3 nm mQDs into the PCR reagent,the photoluminescent(PL)intensities of mQDs decreased gradually as the DNA templates and PCR cycles increased,in an approximate negative linear relation to the DNA concentration logarithm or cycles,the PL peaks exhibited red-shifts synchronously.Mg2+ions decreased the PL intensity of mQDs in a dose-dependent means,and Taq DNA polymerase enhanced the PL intensity of mQDs in a dose-dependent means.Real-time PCR based on mQDs showed an increased sensitivity at least 103 fold higher than that based on SYBR Green I.The specificity of PCR was enhanced in the PCR reagent with less than 1.33mg/mL mQDs.The potential mechanism is also discussed.This novel PCR system based on mQDs has great potential in applications such as ultra-sensitive specific DNA or RNA detection,dynamic molecular imaging,and photoelectric biosensors.
基金Supported by the Natural Science Project of Hubei Provin-cial Department of Education (2005D6002)
文摘Impedance titration was used to determine the surface dissociation characteristics of short-chain carboxyl mercaptan self-assembled monolayers （SAMs）. Based on the change of the cyclic voltammetric peak current and the charge-transfer resistance, which was related to pH value of the solution, the surface pKa of mercaptoacetic acid（MA）, 3-mercaptopropionic acid（MPA） and ω-mercaptohexanic acid（MHA） self-assembled membranes, with ionic strength being 0.1 mol/L, were determined to be 5.20, 4.80, 7.40, respectively. In addition, factors such as time needed for assembling, structure of monolayers and ionic strength, which effected the surface pKa, were studied as well. Such surface pKa shifts were sufficiently explained by interactions between interfacial molecules and hydrophobicity.
文摘In a search for new antimicrobial agents, some new spiro[indol-thiazolidon- 2,4-diones] (6a-c) were synthesized by condensation of 5-substituted isatins 1 with sulfanilamide in MeOH, followed by aroylation with p-nitrobenzoyl chloride in DMF to get compounds 4a-c. Cycloaddition of 4a-c with thioglycolic acid in a dry non-polar solvent (dioxane) gave the targets 6a-c. Also, bis(5-fluorospiro[indoline-3,2’-thiazolidine]-2,4’-dione) (9) was synthesized by condensation of 5-fluoroindoline-2,3-dione with benzene-1,4-diamine (2:1 by mol) in MeOH, which followed by cycloaddition with thioglycolic acid in dioxane gave compound 8. Acylation of the later with 2,2,2-trifluoroacetic anhydride in THF has yielded the target 9. Structures of the products have been deduced from their elemental analysis and spectral data. The in vitro antimicrobial activity of the new systems 6a-c, and 9 was tested.
文摘Objective: Increasing the emergence of Metallo-β-lactamase (MBL) producing gram-negative bacteria and their dexterous horizontal transmission demands rapid and accurate detection. This study was conducted to determine a suitable method to promptly detect MBL-producing gram-negative bacteria. Methods: A total of 103 gram-negative bacteria were identified from various clinical samples at a tertiary care hospital in Dhaka city. MBL producers were detected by two phenotypic methods, the Disk Potentiation Test (DPT) and the Double Disk Synergy Test (DDST) based on β-lactam chelator combinations where EDTA/SMA has been used as an inhibitor and Imipenem, Ceftazidime as substrates. Results: 103 isolates which were identified as Escherichia coli spp, Klebsiella spp, Pseudomonas spp, Acinetobacter spp, Proteus spp, Providencia spp were found to be multidrug-resistant in antibiogram test. Isolates showed complete resistance (100%) to Imipenem, Meropenem, and Amoxiclav. The highest carbapenem-resistant etiological agents were Acinetobacter spp 40 (38.8%) followed by Pseudomonas spp 27 (26.2%), Klebsiella spp 26 (25.2%), Escherichia coli 8 (7.8%), Proteus spp 1 (1%) and Providencia spp 1 (1%). DPT method detected significantly (p = 0.000009) a higher number of MBL-producers (Imipenem with 0.5 M EDTA n = 61, 59.2% & Ceftazidime with 0.5 M EDTA n = 56, 54.4%) compared to the DDST method (Imipenem -0.5 M EDTA n = 43, 41.7%, Imipenem – SMA n = 38, 36.9% & Ceftazidime -0.5 M EDTA n = 15, 14.6%). Conclusion: Pieces of evidence suggest that DPT is a more sensitive method than DDST and could be recommended for identifying MBL-producing bacteria in Bangladeshi hospitals for the proper management of patients, to reduce time constraints and treatment costs.
基金Supported by the National Natural Science Foundation of China (Grant No. 202171042)the Natural Science Foundation of Southwest Petroleum University (Grant No. 2007XJZ044)
文摘The precursor of ZnO has been prepared by refluxing in ethanol at 70°C for 4 h using ZnAc2·H2O as the initial agent. Then ZnO has been prepared from the reaction of LiOH·H2O and the precursor. The ZnO is modified by mercaptoacetic acid (MAA) and detected by SEM and XRD. These ZnO particles have single phase, like-sphere and size of 4.6 nm. The modified effectivity of MAA for the quantum dots (QDs) has been investigated with UV-visible and fluorescence analysis, and the mechanism and property of ZnO light emitting have been discussed under given conditions. The reasons why the fluorescent emission peak of surface defects disappear and the exciton emission peak increase are that MAA effectively covers the surface defects of ZnO and stably coats ZnO particles. At the same time, the effect of the added amount of the MAA, temperature and electrolyte on light-emitting properties of modified product has also been studied. The result shows that the modified ZnO QDs have good fluorescence property, stability and suitable capability of resisting electrolyte. These results are important for biological analysis.
