Cetyl-chitosan, prepared by reacting chitosan with chlorocetane under alkaline condition, is soluble and spontaneously forms nanoparticles about 100 nm in diameter. Infrared spectra (IR) revealed that there was a subs...Cetyl-chitosan, prepared by reacting chitosan with chlorocetane under alkaline condition, is soluble and spontaneously forms nanoparticles about 100 nm in diameter. Infrared spectra (IR) revealed that there was a substitution reaction mainly on the amine groups of chitosan (CS). By using paracetamol (PCTM) as a model drug, the balanced release concentration of PCTM in phosphate buffer solution (pH=7.4) can be decreased with the increase of degree of substitution alkyl and can be reduced effectively even under a lower PCTM loading.展开更多
In order to improve the wettability and biocompatibility of the poly （butylene terephthalate） non-woven （PBTNW）, the method of surface modification is used to graft copolymerization of chitosan （CS） onto the PBT...In order to improve the wettability and biocompatibility of the poly （butylene terephthalate） non-woven （PBTNW）, the method of surface modification is used to graft copolymerization of chitosan （CS） onto the PBTNW under alkylpolyglycoside （APG） inducing. The product is thoroughly characterized with the Fourier transform infrared spectroscopy （FrIR）, the electron spectroscopy for chemical analysis （ESCA）, the thermogravimetric （TG） and the scanning electron microscopy （SEM）. It is found that chitosan is successfully grafted onto PBTNW. In addition, the water contact angles, hemolysis tests and cytotoxicity evaluation tests show an improvement in wettability and biocompatihility as a result of graft copolymerization of chitosan. So the CS-grafted PBTNW exhibits greater superiority than the original PBTNW. The CS-grafted PBTNW can be a candidate for blood filter materials and other medical applications.展开更多
Nanocrystalline cobalt coatings were produced from cobalt sulfate based electrolytes by using pulse current electrodeposition technique.The effects of bath composition and electrodeposition condition on current effici...Nanocrystalline cobalt coatings were produced from cobalt sulfate based electrolytes by using pulse current electrodeposition technique.The effects of bath composition and electrodeposition condition on current efficiency,morphology,structure and hardness of the coatings were investigated and the optimum deposition condition was determined.It was found that increment of cobalt sulfate concentration and sodium dodecyl sulfate(SDS)concentration in the bath had a negligible effect on microhardness of the coatings,while they were effective on electrodeposition current efficiency.Adding saccharin to electrodeposition bath decreased crystallite size of hexagonal close-packed(hcp)cobalt films and increased their microhardness without significant effect on current efficiency.Smoother and less defective coatings were also obtained from baths containing SDS and saccharin.The results revealed that both the current efficiency and microhardness were changed by variation of peak current density and duty cycle.Besides change of smooth morphology of the coatings to needle-shaped one,crystallite sizes and preferred orientation also varied with increasing the current density and duty cycle.展开更多
With the further development and marketing of alkyl polyglycosides （APG）, the development of new domestic and oversea markets and the exploitation of new applications have become the key direction of APG in the futu...With the further development and marketing of alkyl polyglycosides （APG）, the development of new domestic and oversea markets and the exploitation of new applications have become the key direction of APG in the future. The review demonstrated the new progress of APG in synthesis technology and their applications in environmental waste disposal, medicine and stockbreeding in recently years. Thus, the future development of APG was also prospected.展开更多
A new procedure for the highly diastereoselective synthesis of （1S）-trans-cyclopropane derivatives using a fructose derivative as the chiral auxiliary was developed. Chloroacetylated 1,2;4,5-di-O-isopropylidene-D-fr...A new procedure for the highly diastereoselective synthesis of （1S）-trans-cyclopropane derivatives using a fructose derivative as the chiral auxiliary was developed. Chloroacetylated 1,2;4,5-di-O-isopropylidene-D-fructopyranose was reacted with a tertiary amine to form the ammonium salt, which was treated with cesium carbonate to give the cyclopropane derivative through ylide intermediate. The described procedure provides an efficient method to synthesize optically pure dior poly-substituded cyclopropanes.展开更多
In the present study, we aimed to explore the structure-activity relationship for the new amphiphilic material rhamnoside with antibacterial biofilm activity, and provide the basis for selecting rhamnoside with the op...In the present study, we aimed to explore the structure-activity relationship for the new amphiphilic material rhamnoside with antibacterial biofilm activity, and provide the basis for selecting rhamnoside with the optimum antibacterial biofilm activity. A series of alkyl rhamnosides with different carbon chain lengths were obtained by a simple and effective synthesis method. The structure was characterized by ~1H NMR spectrum, and their critical micelle concentration(CMC) was measured by fluorescence probe method. The hydrophilic and lipophilic balance(HLB) value was obtained by calculation. The minimal inhibitory concentration(MIC) of Staphylococcus aureus was determined by the broth double dilution method. The effect of biofilm inhibition and biofilm disruption was assayed by crystal violet method. The results showed that with the increase of carbon chain length, the CMC and HLB of alkyl rhamnosides displayed a linear downward trend, indicating that the lipophilicity and surface activity of the alkyl rhamnoside were increased. At the same time, the antibacterial activity in vitro produced the maximum, ie, 12-hydroxydecanoyl rhamnoside had the strongest antibacterial activity in vitro. Similarly, this material also exhibited the strongest antibacterial biofilm activity in vitro. The results of this study demonstrated that the most potent active material was obtained through the structure-activity relationship and it could be applied antibacterial biofilms in clinical practice.展开更多
C-glycosylation and C-prenylation are two important C-C-bond forming reactions for preparation,diversification and structural modification of natural/unnatural products with pharmacological activities.Here,we describe...C-glycosylation and C-prenylation are two important C-C-bond forming reactions for preparation,diversification and structural modification of natural/unnatural products with pharmacological activities.Here,we described unprecedented enzymatic cascades to C-glycosylate/prenylate different acyl resorcinol derivatives in stepwise,one-pot reactions by combining two promiscuous enzymes,MiCGT,a C-glycosyltransferase,and AtaPT,a prenyltransferase.Five novel bis-C-alkylated products were obtained and structurally identified by MS and NMR spectroscopic data as well as comparison with the literature.This study provided a potential synthetic strategy for synthesizing structurally novel and diverse compounds bearing both C-glycosyl and C-prenyl moieties by a two-step,enzymatic bis-C-alkylation.展开更多
文摘Cetyl-chitosan, prepared by reacting chitosan with chlorocetane under alkaline condition, is soluble and spontaneously forms nanoparticles about 100 nm in diameter. Infrared spectra (IR) revealed that there was a substitution reaction mainly on the amine groups of chitosan (CS). By using paracetamol (PCTM) as a model drug, the balanced release concentration of PCTM in phosphate buffer solution (pH=7.4) can be decreased with the increase of degree of substitution alkyl and can be reduced effectively even under a lower PCTM loading.
文摘In order to improve the wettability and biocompatibility of the poly （butylene terephthalate） non-woven （PBTNW）, the method of surface modification is used to graft copolymerization of chitosan （CS） onto the PBTNW under alkylpolyglycoside （APG） inducing. The product is thoroughly characterized with the Fourier transform infrared spectroscopy （FrIR）, the electron spectroscopy for chemical analysis （ESCA）, the thermogravimetric （TG） and the scanning electron microscopy （SEM）. It is found that chitosan is successfully grafted onto PBTNW. In addition, the water contact angles, hemolysis tests and cytotoxicity evaluation tests show an improvement in wettability and biocompatihility as a result of graft copolymerization of chitosan. So the CS-grafted PBTNW exhibits greater superiority than the original PBTNW. The CS-grafted PBTNW can be a candidate for blood filter materials and other medical applications.
文摘Nanocrystalline cobalt coatings were produced from cobalt sulfate based electrolytes by using pulse current electrodeposition technique.The effects of bath composition and electrodeposition condition on current efficiency,morphology,structure and hardness of the coatings were investigated and the optimum deposition condition was determined.It was found that increment of cobalt sulfate concentration and sodium dodecyl sulfate(SDS)concentration in the bath had a negligible effect on microhardness of the coatings,while they were effective on electrodeposition current efficiency.Adding saccharin to electrodeposition bath decreased crystallite size of hexagonal close-packed(hcp)cobalt films and increased their microhardness without significant effect on current efficiency.Smoother and less defective coatings were also obtained from baths containing SDS and saccharin.The results revealed that both the current efficiency and microhardness were changed by variation of peak current density and duty cycle.Besides change of smooth morphology of the coatings to needle-shaped one,crystallite sizes and preferred orientation also varied with increasing the current density and duty cycle.
文摘With the further development and marketing of alkyl polyglycosides （APG）, the development of new domestic and oversea markets and the exploitation of new applications have become the key direction of APG in the future. The review demonstrated the new progress of APG in synthesis technology and their applications in environmental waste disposal, medicine and stockbreeding in recently years. Thus, the future development of APG was also prospected.
基金National Natural Science Foundation of China (Grant No. 20602001)
文摘A new procedure for the highly diastereoselective synthesis of （1S）-trans-cyclopropane derivatives using a fructose derivative as the chiral auxiliary was developed. Chloroacetylated 1,2;4,5-di-O-isopropylidene-D-fructopyranose was reacted with a tertiary amine to form the ammonium salt, which was treated with cesium carbonate to give the cyclopropane derivative through ylide intermediate. The described procedure provides an efficient method to synthesize optically pure dior poly-substituded cyclopropanes.
基金National Natural Science Foundation of China(Grant No.81573381)CAMS Initiative for Innovative Medicine(Grant No.CAMS-I2M-1-012)
文摘In the present study, we aimed to explore the structure-activity relationship for the new amphiphilic material rhamnoside with antibacterial biofilm activity, and provide the basis for selecting rhamnoside with the optimum antibacterial biofilm activity. A series of alkyl rhamnosides with different carbon chain lengths were obtained by a simple and effective synthesis method. The structure was characterized by ~1H NMR spectrum, and their critical micelle concentration(CMC) was measured by fluorescence probe method. The hydrophilic and lipophilic balance(HLB) value was obtained by calculation. The minimal inhibitory concentration(MIC) of Staphylococcus aureus was determined by the broth double dilution method. The effect of biofilm inhibition and biofilm disruption was assayed by crystal violet method. The results showed that with the increase of carbon chain length, the CMC and HLB of alkyl rhamnosides displayed a linear downward trend, indicating that the lipophilicity and surface activity of the alkyl rhamnoside were increased. At the same time, the antibacterial activity in vitro produced the maximum, ie, 12-hydroxydecanoyl rhamnoside had the strongest antibacterial activity in vitro. Similarly, this material also exhibited the strongest antibacterial biofilm activity in vitro. The results of this study demonstrated that the most potent active material was obtained through the structure-activity relationship and it could be applied antibacterial biofilms in clinical practice.
基金National Natural Science Foundation of China(Grant Nos.21572277,81573317 and 81703369)CAMS Innovation Fund for Medical Sciences(CIFMS-2016-I2M-3-012)
文摘C-glycosylation and C-prenylation are two important C-C-bond forming reactions for preparation,diversification and structural modification of natural/unnatural products with pharmacological activities.Here,we described unprecedented enzymatic cascades to C-glycosylate/prenylate different acyl resorcinol derivatives in stepwise,one-pot reactions by combining two promiscuous enzymes,MiCGT,a C-glycosyltransferase,and AtaPT,a prenyltransferase.Five novel bis-C-alkylated products were obtained and structurally identified by MS and NMR spectroscopic data as well as comparison with the literature.This study provided a potential synthetic strategy for synthesizing structurally novel and diverse compounds bearing both C-glycosyl and C-prenyl moieties by a two-step,enzymatic bis-C-alkylation.
