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2004 Volume 15 Issue 8
2004, 15(8): 883-884
Abstract:
The β-aminocarboxylic acid derivatives were synthesized by Michael addition reaction of alkyl amine and α,β-unsaturated carbonyl compounds in the presence of potassium fluoride on alumina.
The β-aminocarboxylic acid derivatives were synthesized by Michael addition reaction of alkyl amine and α,β-unsaturated carbonyl compounds in the presence of potassium fluoride on alumina.
2004, 15(8): 885-888
Abstract:
On the basis of the Zaleplon structure, novel pyrazolo[1,5-a]pyrimidines were designed and prepared for studies on their hypnotic activity.This paper reported the synthesis of twelve new 5-methyl-7-substituted-pyrazolo[1,5-a]pyrimidine-3-carbonitrile derivatives by using simple starting materials such as propane dinitrile and triethyl orthoformate.The structures of the derived target compounds were confirmed by their IR and 1H-NMR spectroscopic data.The preliminary pharmacological evaluations indicated that some compounds showed hypnotic activity, while derivative 1c was the most potent one.
On the basis of the Zaleplon structure, novel pyrazolo[1,5-a]pyrimidines were designed and prepared for studies on their hypnotic activity.This paper reported the synthesis of twelve new 5-methyl-7-substituted-pyrazolo[1,5-a]pyrimidine-3-carbonitrile derivatives by using simple starting materials such as propane dinitrile and triethyl orthoformate.The structures of the derived target compounds were confirmed by their IR and 1H-NMR spectroscopic data.The preliminary pharmacological evaluations indicated that some compounds showed hypnotic activity, while derivative 1c was the most potent one.
2004, 15(8): 889-891
Abstract:
A facile synthesis of N-methyl-N-aryl carbamates from aromatic amines and dimethyl carbonate (DMC) has been achieved with high yields in the presence of potassium carbonate (K2CO3) and tetrabutylammonium bromide (Bu4NBr) under solvent-free conditions.
A facile synthesis of N-methyl-N-aryl carbamates from aromatic amines and dimethyl carbonate (DMC) has been achieved with high yields in the presence of potassium carbonate (K2CO3) and tetrabutylammonium bromide (Bu4NBr) under solvent-free conditions.
2004, 15(8): 892-894
Abstract:
Some hymecromone derivatives containing chiral 1,1'-bi-2-naphthyl moiety were synthesized and their photodimerizations were investigated.It was found that fluorescence intensity and optical rotation of the new chiral hymecromone derivatives could be regulated by light.This property has potential significance for developing a new type of dual-mode molecular switch.
Some hymecromone derivatives containing chiral 1,1'-bi-2-naphthyl moiety were synthesized and their photodimerizations were investigated.It was found that fluorescence intensity and optical rotation of the new chiral hymecromone derivatives could be regulated by light.This property has potential significance for developing a new type of dual-mode molecular switch.
2004, 15(8): 895-898
Abstract:
An effective synthetic route for preparation of 2-chloro-6-fluorobenzonitrile, 2-chloro-6-fluorobenzamide and 2-chloro-6-fluorobenzoic acid has been described.It includes diazotization, fluorination, ammoxidation and hydrolysis reactions.
An effective synthetic route for preparation of 2-chloro-6-fluorobenzonitrile, 2-chloro-6-fluorobenzamide and 2-chloro-6-fluorobenzoic acid has been described.It includes diazotization, fluorination, ammoxidation and hydrolysis reactions.
2004, 15(8): 899-902
Abstract:
In the studying of the stereospecific hydroxylation of different Δ5-steroids with performic acid, followed by hydrolysis with CH3OH/KOH, we found 19-substituting groups considerably affected the reaction and we put forward the mechanism.
In the studying of the stereospecific hydroxylation of different Δ5-steroids with performic acid, followed by hydrolysis with CH3OH/KOH, we found 19-substituting groups considerably affected the reaction and we put forward the mechanism.
2004, 15(8): 903-906
Abstract:
The paper reported a novel and efficient aerobic oxidative coupling reaction of 2-naphthol derivatives catalyzed by CuCu (Ⅰ or Ⅱ)N-alkylimidazole complexes in excellent yields.The crystal structure of CuCu (Ⅱ)N-methylimidazole complex to be determined by X-Ray.
The paper reported a novel and efficient aerobic oxidative coupling reaction of 2-naphthol derivatives catalyzed by CuCu (Ⅰ or Ⅱ)N-alkylimidazole complexes in excellent yields.The crystal structure of CuCu (Ⅱ)N-methylimidazole complex to be determined by X-Ray.
2004, 15(8): 907-910
Abstract:
Ribavirin has been used in urgency to treat SARS patients recently.In order to study its antiviral mechanism by photolabeling approach, we have synthesized and characterized 5-azido-1-(-D-ribofuranosyl-1,2,4-triazole-3-carboxiamide 1 as a photolabeling probe of ribavirin.The azidotriazole nucleoside showed rapid and clean photochemical reaction, suggesting that 1 is a promising probe to study the antiviral mechanism of ribarivin by photolabeling.
Ribavirin has been used in urgency to treat SARS patients recently.In order to study its antiviral mechanism by photolabeling approach, we have synthesized and characterized 5-azido-1-(-D-ribofuranosyl-1,2,4-triazole-3-carboxiamide 1 as a photolabeling probe of ribavirin.The azidotriazole nucleoside showed rapid and clean photochemical reaction, suggesting that 1 is a promising probe to study the antiviral mechanism of ribarivin by photolabeling.
2004, 15(8): 911-914
Abstract:
The combination of (CF3CO)2O/Et3N is found to be a mild and efficient dehydration condition forβ-hydroxy-α-diazo compounds.
The combination of (CF3CO)2O/Et3N is found to be a mild and efficient dehydration condition forβ-hydroxy-α-diazo compounds.
2004, 15(8): 915-918
Abstract:
Synthesis of a novel octopus porphyrin with polyglycol chains 1a was achieved.The catalytic activity of 1a's manganese complex for the epoxidation of cholesterol derivatives with PhIO give a satisfactory conversion and regioselectivity.
Synthesis of a novel octopus porphyrin with polyglycol chains 1a was achieved.The catalytic activity of 1a's manganese complex for the epoxidation of cholesterol derivatives with PhIO give a satisfactory conversion and regioselectivity.
2004, 15(8): 919-920
Abstract:
A new diterpenoid was isolated from the bark of Larix olgensis Henry var.koreana Nakai.Its structure was elucidated as 5S, 9S, 10R-labda-8 (17), 13-diene-6α, 15-diol 1 by spectroscopic methods.
A new diterpenoid was isolated from the bark of Larix olgensis Henry var.koreana Nakai.Its structure was elucidated as 5S, 9S, 10R-labda-8 (17), 13-diene-6α, 15-diol 1 by spectroscopic methods.
2004, 15(8): 921-924
Abstract:
Four new neo-lignans were isolated from the chloroform portion of 70% ethanol extract of the seed crusts of Trewia nudiflora L., and were determined to be 9'-methoxy-7'-en-3',8:4',7-di-epoxyneolignan-3,4,9-triol 1, 9'-methoxy-7'-en-3',7:4',8-diepoxyneolignan-3,4,9-triol 2, 9'-ethoxy-7'-en-3',8:4',7-diepoxyneolignan-3,4,9-triol 3, 9'-butoxy-7'-en-3',8:4',7-diepoxy-neolignan-3,4,9-triol 4, respectively, on the basis of spectral data.The antimicrobial bioassays showed that 4 had evident inhibitory activity against Mycobacterium tuberculosis.
Four new neo-lignans were isolated from the chloroform portion of 70% ethanol extract of the seed crusts of Trewia nudiflora L., and were determined to be 9'-methoxy-7'-en-3',8:4',7-di-epoxyneolignan-3,4,9-triol 1, 9'-methoxy-7'-en-3',7:4',8-diepoxyneolignan-3,4,9-triol 2, 9'-ethoxy-7'-en-3',8:4',7-diepoxyneolignan-3,4,9-triol 3, 9'-butoxy-7'-en-3',8:4',7-diepoxy-neolignan-3,4,9-triol 4, respectively, on the basis of spectral data.The antimicrobial bioassays showed that 4 had evident inhibitory activity against Mycobacterium tuberculosis.
2004, 15(8): 925-926
Abstract:
A new dihydroflavone glycoside was isolated from the underground parts of Glycyrrhiza uralensis.Its structure was elucidated as 7-hydroxyl-4'-O-β-D-(6"-O-α-hydroxylpropionyl) glucopyranosyl dihydroflavone by spectral methods.
A new dihydroflavone glycoside was isolated from the underground parts of Glycyrrhiza uralensis.Its structure was elucidated as 7-hydroxyl-4'-O-β-D-(6"-O-α-hydroxylpropionyl) glucopyranosyl dihydroflavone by spectral methods.
2004, 15(8): 927-930
Abstract:
Fragmentation of phosphorylated Tau peptides in matrix assisted laser desorption-/ionization-time of flight-mass spectrometry (MALDI-TOF-MS) has been investigated.According to the post-source decay (PSD) in MALDI-TOF-MS, there are two different patterns of cleavage in phosphopeptides, which can be used to determine the phosphorylated site in peptides.In the synthetic tau peptides, the fragmentation at proline residue occurs strongly and this is useful to determine the structure of tau peptides.
Fragmentation of phosphorylated Tau peptides in matrix assisted laser desorption-/ionization-time of flight-mass spectrometry (MALDI-TOF-MS) has been investigated.According to the post-source decay (PSD) in MALDI-TOF-MS, there are two different patterns of cleavage in phosphopeptides, which can be used to determine the phosphorylated site in peptides.In the synthetic tau peptides, the fragmentation at proline residue occurs strongly and this is useful to determine the structure of tau peptides.
2004, 15(8): 931-934
Abstract:
Hydrophilic hyperbranched poly(ester-amine) (HPEA) synthesized from diethanolamine and methyl acrylate was used as phase transfer agent for the first time to transfer methyl orange (MO) from water into chloroform.This process was quantified by UV-Vis spectra.A possible mechanism was put forward based on the formation of amphiphilic aggregates.
Hydrophilic hyperbranched poly(ester-amine) (HPEA) synthesized from diethanolamine and methyl acrylate was used as phase transfer agent for the first time to transfer methyl orange (MO) from water into chloroform.This process was quantified by UV-Vis spectra.A possible mechanism was put forward based on the formation of amphiphilic aggregates.
2004, 15(8): 935-938
Abstract:
A new method to separate diazepam, nitrazepam, estazolam, alprazolam was established on both C18 and C8 CEC columns.The influence of separation voltage, Tris concentration, column temperature and the percentage of acetonitrile on the resolution and retention behavior of four benzodiazepines was investigated.The results showed that the percentage of acetonitrile had the largest effect on the resolution and retention behavior of the four benzodiazepines.Other separation conditions had also effects on the resolution and retention behavior, but smaller than the concentration of acetonitrile.Optimum separation conditions were obtained to separate four benzodiazepines on C18 and C8 CEC columns.
A new method to separate diazepam, nitrazepam, estazolam, alprazolam was established on both C18 and C8 CEC columns.The influence of separation voltage, Tris concentration, column temperature and the percentage of acetonitrile on the resolution and retention behavior of four benzodiazepines was investigated.The results showed that the percentage of acetonitrile had the largest effect on the resolution and retention behavior of the four benzodiazepines.Other separation conditions had also effects on the resolution and retention behavior, but smaller than the concentration of acetonitrile.Optimum separation conditions were obtained to separate four benzodiazepines on C18 and C8 CEC columns.
2004, 15(8): 939-942
Abstract:
Two different immunoassay methods, competitive indirect enzyme-linked immuno-sorbent assay (CI-ELISA) and amplificative competitive indirect ELISA (ACI-ELISA) using biotin-avidin complex system were studied to detect rhEPO.The linear ranges were 50-20000 ng/mL and 10-50000 ng/mL for CI-ELISA and ACI-ELISA, respectively.The low detection limits of CI-ELISA and ACI-ELISA were 62.8 ng/mL and 8.5 ng/mL, respectively.
Two different immunoassay methods, competitive indirect enzyme-linked immuno-sorbent assay (CI-ELISA) and amplificative competitive indirect ELISA (ACI-ELISA) using biotin-avidin complex system were studied to detect rhEPO.The linear ranges were 50-20000 ng/mL and 10-50000 ng/mL for CI-ELISA and ACI-ELISA, respectively.The low detection limits of CI-ELISA and ACI-ELISA were 62.8 ng/mL and 8.5 ng/mL, respectively.
2004, 15(8): 943-946
Abstract:
N-Conjugated antigen was synthesized and polyclonal antibody with high specificity was obtained from immunizing animals.With this polyclonal antibody, a rapid and efficient CEIA-LIF method was developed to determine the free morphine in urine of abusers.The detection limit was calculated to be 40 ng/mL.Simulated urine samples were analyzed with good recoveries, which showed the feasibility of its application in specific morphine determination in urine of morphine abusers.
N-Conjugated antigen was synthesized and polyclonal antibody with high specificity was obtained from immunizing animals.With this polyclonal antibody, a rapid and efficient CEIA-LIF method was developed to determine the free morphine in urine of abusers.The detection limit was calculated to be 40 ng/mL.Simulated urine samples were analyzed with good recoveries, which showed the feasibility of its application in specific morphine determination in urine of morphine abusers.
2004, 15(8): 947-950
Abstract:
A micellar electrokinetic capillary chromatography (MECC) was developed for the determination of aniline and 6 substituted anilines.The seven components were separated within 25 min in the buffer solution of 40 mmol/L sodium borate and 100 mmol/L SDS.It was found that the separation was dependent on operating voltage, pH value, borate and SDS concentrations.The analytical performance was examined in terms of linear response and reproducibility.Wastewater was determined by the established method.
A micellar electrokinetic capillary chromatography (MECC) was developed for the determination of aniline and 6 substituted anilines.The seven components were separated within 25 min in the buffer solution of 40 mmol/L sodium borate and 100 mmol/L SDS.It was found that the separation was dependent on operating voltage, pH value, borate and SDS concentrations.The analytical performance was examined in terms of linear response and reproducibility.Wastewater was determined by the established method.
2004, 15(8): 951-953
Abstract:
From the EtOH extract of the barks of Morus macroura Miq, a new benzofuran derivative, macrourin D 1, together with four known benzofuran derivatives, macrourin B 2, 2-(3, 5-dihydroxyphenyl)-5, 6-dihydroxybenzofuran 3, moracin M 4, and mulberroside C 5 were isolated, and their structures were determined on the basis of spectroscopic evidence and chemical correlation with known compounds.
From the EtOH extract of the barks of Morus macroura Miq, a new benzofuran derivative, macrourin D 1, together with four known benzofuran derivatives, macrourin B 2, 2-(3, 5-dihydroxyphenyl)-5, 6-dihydroxybenzofuran 3, moracin M 4, and mulberroside C 5 were isolated, and their structures were determined on the basis of spectroscopic evidence and chemical correlation with known compounds.
2004, 15(8): 954-956
Abstract:
A novel heterocyclic hexacoordinate organotin(Ⅳ) complex, bis(O-vanillin)-semi ethylenediamino dibenzyltin (VEDBT) was synthesized by the reaction of dibenzyltin dichloride with bis(O-vanillin)-semiethyenediamine, its structure has been characterized by spectral methods.The electrodes using VEDBT as a neutral carrier show high selectivity for salicylate anions.
A novel heterocyclic hexacoordinate organotin(Ⅳ) complex, bis(O-vanillin)-semi ethylenediamino dibenzyltin (VEDBT) was synthesized by the reaction of dibenzyltin dichloride with bis(O-vanillin)-semiethyenediamine, its structure has been characterized by spectral methods.The electrodes using VEDBT as a neutral carrier show high selectivity for salicylate anions.
2004, 15(8): 957-960
Abstract:
The TiO2, MoO3, PEO doped four-member tungstic acid sols were prepared for the first time.The stability of different doped content sols were investigated and optimized with rotational viscometer.The four-member doped tungstic acid sol was very stable which could be stored more than two months at room temperature.The WO3 electrochromic film prepared from this doped four-member tungstic acid sol had excellent performance and longevity of service.
The TiO2, MoO3, PEO doped four-member tungstic acid sols were prepared for the first time.The stability of different doped content sols were investigated and optimized with rotational viscometer.The four-member doped tungstic acid sol was very stable which could be stored more than two months at room temperature.The WO3 electrochromic film prepared from this doped four-member tungstic acid sol had excellent performance and longevity of service.
2004, 15(8): 961-964
Abstract:
The interaction of β-cyclodextrin (β-CD) and the modified cyclodextrins, hydroxy propyl-(-cyclodextrin (HP-β-CD), sulfobutylether-β-cyclodextrin (SBE-β-CD) and synthesized meso-tetrakis(4-N-ethylpyridiniurmyl)porphyrin (TEPyP) in aqueous solution has been studied by spectroscopic methods systematically.A significant change in fluorescence and absorption properties has been observed in the presence of β-CD, HP-β-CD and SBE-β-CD.The stoichiometry and formation constants have been determined by the steady-state fluorescence technique.The results showed that the β-CD derivatives were prior to the native β-CD and the hydrogen bonding and static electric forces played important roles in the formation of the inclusion complexes.The conformation was further confirmed by NMR spectroscopy.
The interaction of β-cyclodextrin (β-CD) and the modified cyclodextrins, hydroxy propyl-(-cyclodextrin (HP-β-CD), sulfobutylether-β-cyclodextrin (SBE-β-CD) and synthesized meso-tetrakis(4-N-ethylpyridiniurmyl)porphyrin (TEPyP) in aqueous solution has been studied by spectroscopic methods systematically.A significant change in fluorescence and absorption properties has been observed in the presence of β-CD, HP-β-CD and SBE-β-CD.The stoichiometry and formation constants have been determined by the steady-state fluorescence technique.The results showed that the β-CD derivatives were prior to the native β-CD and the hydrogen bonding and static electric forces played important roles in the formation of the inclusion complexes.The conformation was further confirmed by NMR spectroscopy.
2004, 15(8): 965-968
Abstract:
Two novel rhenium(Ⅰ) 2,2'-bipyridyl complexes,[(4,4'-di-COOEt-bipy) Re(CO)3 (NCCH3)PF6] and[(4,4'-di-COOEt-bipy) Re (CO)3 (NCS)], a model complex[(4,4'-di-COOEt-bipy) Re (CO)3 (pyridine)PF6], were synthesized.Their ground state electronic spectra and emission spectra were measured in acetonitrile.The MLCT absorption maximum of the complex exhibited a considerable red shift as the ligand changed from pyridine to CNCH3, or SCN.
Two novel rhenium(Ⅰ) 2,2'-bipyridyl complexes,[(4,4'-di-COOEt-bipy) Re(CO)3 (NCCH3)PF6] and[(4,4'-di-COOEt-bipy) Re (CO)3 (NCS)], a model complex[(4,4'-di-COOEt-bipy) Re (CO)3 (pyridine)PF6], were synthesized.Their ground state electronic spectra and emission spectra were measured in acetonitrile.The MLCT absorption maximum of the complex exhibited a considerable red shift as the ligand changed from pyridine to CNCH3, or SCN.
2004, 15(8): 969-972
Abstract:
A novel Ru(Ⅱ) tris-bipyridyl complex, Ru(bpy)2[bpy(CO2H)(CO2Et)] [PF6]2 is prepared in a simple and convenient process.It will be an alternative of Ru(bpy)2bpy(CO2Et)2(PF6)2 to be used in solar cells as photosensitive dyes.
A novel Ru(Ⅱ) tris-bipyridyl complex, Ru(bpy)2[bpy(CO2H)(CO2Et)] [PF6]2 is prepared in a simple and convenient process.It will be an alternative of Ru(bpy)2bpy(CO2Et)2(PF6)2 to be used in solar cells as photosensitive dyes.
2004, 15(8): 973-976
Abstract:
Three novel chiral binuclear Mn(Ⅲ)-Schiff-base complexes have been synthesized and the application of these complexes in the asymmetric epoxidation of trans-stilbene is described, catalytic mechanism is also discussed briefly.
Three novel chiral binuclear Mn(Ⅲ)-Schiff-base complexes have been synthesized and the application of these complexes in the asymmetric epoxidation of trans-stilbene is described, catalytic mechanism is also discussed briefly.
2004, 15(8): 977-980
Abstract:
Several Mo-V-Te-O mixed metal oxides catalysts with different dopant were prepared and used for catalytic oxidation propane to acrolein.It was revealed that the addition of P could greatly improve the performance of the Mo-V-Te-O catalyst.The catalysts were examined by XRD and H2-TPR.The XRD characteristic of the Mo-V-Te-P-O showed that the addition of P could aggrandize the (V0.07Mo0.93)5O14 phase.H2-TPR illuminated that the MoV0.3Te0.23P0.15On catalyst took on the best redox ability.
Several Mo-V-Te-O mixed metal oxides catalysts with different dopant were prepared and used for catalytic oxidation propane to acrolein.It was revealed that the addition of P could greatly improve the performance of the Mo-V-Te-O catalyst.The catalysts were examined by XRD and H2-TPR.The XRD characteristic of the Mo-V-Te-P-O showed that the addition of P could aggrandize the (V0.07Mo0.93)5O14 phase.H2-TPR illuminated that the MoV0.3Te0.23P0.15On catalyst took on the best redox ability.
2004, 15(8): 981-984
Abstract:
The nucleation mechanisms of cobalt from sulfate solutions were studied by utilizing the electrochemical technique, chronoamperometry.It was found that the recorded current-time transients introduced from 1.0 mol/L CoSO4 solution were complexes with unusual shapes.All characteristic features were identified as separate process.The instantaneous or progressive nucleation with 2D or 3D growth exists during the cobalt deposition, depending on the applied potentials.
The nucleation mechanisms of cobalt from sulfate solutions were studied by utilizing the electrochemical technique, chronoamperometry.It was found that the recorded current-time transients introduced from 1.0 mol/L CoSO4 solution were complexes with unusual shapes.All characteristic features were identified as separate process.The instantaneous or progressive nucleation with 2D or 3D growth exists during the cobalt deposition, depending on the applied potentials.
2004, 15(8): 985-988
Abstract:
Weight-loss trials and potentiodynamic polarization curves have been used to study the inhibitive properties of alkylpolyglucoside (APG) towards the 907 steel in seawater.The inhibition was different, if the length of alkyl chain APG was different.As the result, calcium gluconate, zinc sulfate and APG can protect 907 steel from being corrupted in static seawater.The compound corrosion inhibitor was found to control both the anodic process and the cathodic process.
Weight-loss trials and potentiodynamic polarization curves have been used to study the inhibitive properties of alkylpolyglucoside (APG) towards the 907 steel in seawater.The inhibition was different, if the length of alkyl chain APG was different.As the result, calcium gluconate, zinc sulfate and APG can protect 907 steel from being corrupted in static seawater.The compound corrosion inhibitor was found to control both the anodic process and the cathodic process.
2004, 15(8): 989-992
Abstract:
Magnesium aluminium hydrotalcite (Mg-Al-HT) with molar ratio of Mg-to-Al of 3 to 1 was prepared and characterized by X-ray diffraction (XRD) and infrared spectra (IR).The performances of Mg-Al-HT for the adsorption and desorption of NOx were studied.The results indicated that the adsorption capacity of the hydrotalcite for NOx was 1398.2 mg/g, and it was higher than the acticarbon's.The adsorption capacities depended on adsorption time and temperature.Mg-Al-HT could be regenerated by thermal decomposition, and the adsorption efficiency had not changed markedly after three cycles.
Magnesium aluminium hydrotalcite (Mg-Al-HT) with molar ratio of Mg-to-Al of 3 to 1 was prepared and characterized by X-ray diffraction (XRD) and infrared spectra (IR).The performances of Mg-Al-HT for the adsorption and desorption of NOx were studied.The results indicated that the adsorption capacity of the hydrotalcite for NOx was 1398.2 mg/g, and it was higher than the acticarbon's.The adsorption capacities depended on adsorption time and temperature.Mg-Al-HT could be regenerated by thermal decomposition, and the adsorption efficiency had not changed markedly after three cycles.
2004, 15(8): 993-996
Abstract:
A new economic and convenient method to modify the surface of microporous polypropylene (PP) membranes with phospholipid polymer was given.The process included the photo-irradiated graft polymerization of N,N-dimethylaminoethyl methacrylate (DMAEMA) and the ring-opening reaction of the grafted polyDMAEMA with 2-alkyloxy-2-oxide-1,3,2-dioxo-phospholanes (AOP).Four AOPs, whose alkyloxy groups consisted of dodecyl, tetradecyl, hexadecyl and octadecyl moieties, were used to convert the grafted polyDMAEMA to phospholipid polymers.FT-IR spectra confirmed the chemical change of membrane surface.Platelets adhesion experiment indicated that PP membrane with excellent blood compatible surface could be fabricated by this method.
A new economic and convenient method to modify the surface of microporous polypropylene (PP) membranes with phospholipid polymer was given.The process included the photo-irradiated graft polymerization of N,N-dimethylaminoethyl methacrylate (DMAEMA) and the ring-opening reaction of the grafted polyDMAEMA with 2-alkyloxy-2-oxide-1,3,2-dioxo-phospholanes (AOP).Four AOPs, whose alkyloxy groups consisted of dodecyl, tetradecyl, hexadecyl and octadecyl moieties, were used to convert the grafted polyDMAEMA to phospholipid polymers.FT-IR spectra confirmed the chemical change of membrane surface.Platelets adhesion experiment indicated that PP membrane with excellent blood compatible surface could be fabricated by this method.
2004, 15(8): 997-1000
Abstract:
Native calf thymus double stranded DNA (ct-dsDNA) is successfully immobilized from solution onto carbon substrates by covalent linkages under an optimized deposition potential of 1.8±0.3 V vs.50 mmol/L NaCl-Ag/AgCl.The long chain DNA fabricates a layer of well conductive nano-netting intertexture, which is stable in pH 14 alkaline solution and in boiling water.The ct-dsDNA modified carbon fiber disk electrode shows two to three orders of magnitude enlarged electrode effective surface area and similarly enlarged voltammetric responses to Co(phen)33+ and dopamine.Thermal dissociated single stranded ct-DNA can also lead to similar result.This modified electrode will find wide applications in the fields of DNA-based electrochemical biosensors.
Native calf thymus double stranded DNA (ct-dsDNA) is successfully immobilized from solution onto carbon substrates by covalent linkages under an optimized deposition potential of 1.8±0.3 V vs.50 mmol/L NaCl-Ag/AgCl.The long chain DNA fabricates a layer of well conductive nano-netting intertexture, which is stable in pH 14 alkaline solution and in boiling water.The ct-dsDNA modified carbon fiber disk electrode shows two to three orders of magnitude enlarged electrode effective surface area and similarly enlarged voltammetric responses to Co(phen)33+ and dopamine.Thermal dissociated single stranded ct-DNA can also lead to similar result.This modified electrode will find wide applications in the fields of DNA-based electrochemical biosensors.
A Novel Method for Preparing Polyurethane Based Conductive Composites with Low Percolation Threshold
2004, 15(8): 1001-1004
Abstract:
A novel method for preparing conductive carbon black filled polymer composites with low percolation threshold from polyurethane emulsion are reported in this paper.The experimental results indicate that with a rise in carbon black concentration the insulator-conductor transition in the emulsion blended composites occurs at 0.8-1.4vol%.In contrast, the solution blended composites exhibit drastic increase in conductivity at conducting filler fraction as high as 12.3-13.3vol%.It is demonstrated that the composites microstructure rather than chemical structure of the matrix polymer predominantly determines the electrical conduction performance of the composites.
A novel method for preparing conductive carbon black filled polymer composites with low percolation threshold from polyurethane emulsion are reported in this paper.The experimental results indicate that with a rise in carbon black concentration the insulator-conductor transition in the emulsion blended composites occurs at 0.8-1.4vol%.In contrast, the solution blended composites exhibit drastic increase in conductivity at conducting filler fraction as high as 12.3-13.3vol%.It is demonstrated that the composites microstructure rather than chemical structure of the matrix polymer predominantly determines the electrical conduction performance of the composites.
2004, 15(8): 1005-1008
Abstract:
A simple two-step method was developed to prepare silver nanoshells coated on silica paticles.The method involves two steps:concentration of reaction precursor (AgNO3) on particle surfaces and subsequent reduction by formaldehyde.The obtained composite particles were characterized by TEM, ED, and SEM-EDS measurements.The results show that the silver nanoshell is coated on silica particle surface in the form of a polycrystalline (cubic structure) layer with average thickness of 20 nm and weight percentage of 19%.
A simple two-step method was developed to prepare silver nanoshells coated on silica paticles.The method involves two steps:concentration of reaction precursor (AgNO3) on particle surfaces and subsequent reduction by formaldehyde.The obtained composite particles were characterized by TEM, ED, and SEM-EDS measurements.The results show that the silver nanoshell is coated on silica particle surface in the form of a polycrystalline (cubic structure) layer with average thickness of 20 nm and weight percentage of 19%.
