With the aim of creating biodegradable materials for medical devices clinical appointments with high hemocompatibility we have developed a new polymer product.The basis of this product is plasticized by polyethylene g...With the aim of creating biodegradable materials for medical devices clinical appointments with high hemocompatibility we have developed a new polymer product.The basis of this product is plasticized by polyethylene glycol bacterial copolymer of hydroxybutyrate and oxovalerate. A well-known antitbrombotic supplement--acetylsalicylic acid has been added to improve hemocompatibility in the polymer. The results of our studies showed a controlled prolonged separation of acetylsalicylic acid from polymeric material in the blood. We studied in vitro the dynamics of liberation of acetylsalicylic acid from polymeric coatings. It was shown that the concentration of polyethylene glycol and the thickness of the polymer layer can affect the rate of diffusion of acetylsalicylic acid from polymer films.展开更多
The title complex, potassium triethylenetetraaminehexaacetatodi [oxo-vanadium (Ⅳ)] hexahydrate K2[V2O2(ttha)]6(H2O), was synthesized in aqueous solution and its crystal structure has been determined by X-ray diffract...The title complex, potassium triethylenetetraaminehexaacetatodi [oxo-vanadium (Ⅳ)] hexahydrate K2[V2O2(ttha)]6(H2O), was synthesized in aqueous solution and its crystal structure has been determined by X-ray diffraction. The complex belongs to a triclinic system, space group P?with a = 6.645(1), b = 9.870(2), c = 13.263(3) ? a = 70.68(3), b = 76.27(3), g = 71.66(3), V = 770.5(3) 3, Mr = 808.58, Dc = 1.743 g/cm3, Z = 1, m = 0.968 mm-1, l(MoKa) = 0.71073 and F(000) = 416. The final R = 0.0465 and wR = 0.1091 for 2974 observed diffractions with I ≥ 2s(I). In the complex, the V atom is octahedrally coordinated to the oxo ligand, two N and three O atoms of the triethylenetetraaminehexaacetic (TTHA) ligand. All of the ten chelating sites are coordinated to the two vanadium atoms, and the coordination octahedron is distorted. Each [V2O2(ttha)]2- ion is further connected by the K+ ions through carboxyl groups of TTHA6- ion, forming a two dimensional network structure.展开更多
The catalytic transformation of cellulose into key building-block or platform chemicals such as 5-hydoxymethylfurfural(HMF),levulinic acid,and lactic acid under mild conditions,has attracted much attention in recent y...The catalytic transformation of cellulose into key building-block or platform chemicals such as 5-hydoxymethylfurfural(HMF),levulinic acid,and lactic acid under mild conditions,has attracted much attention in recent years,as these conversions can be operated without consumption of hydrogen or oxygen and thus are more economical compared to the hydrogenolysis or oxidation of cellulose.This review article highlights recent advances in the development of novel catalysts or catalytic processes for the conversion of cellulose and its derived carbohydrates into HMF,levulinic acid,and lactic acid or their esters under inert atmosphere.We also analyze efficient catalytic systems for HMF production,in particular Lewis acids combined with ionic liquid or biphasic systems.For the formations of levulinic and lactic acids or their esters,we focus on the reactions in aqueous and alcohol media catalyzed by multifunctional catalysts that combine the functions of hydrolysis,isomerization,and dehydration-rehydration or retro-aldol reactions.The reaction mechanism for each process will also be discussed to gain insights into the activation of C–O and C–C bonds in the absence of hydrogen or oxygen.展开更多
文摘With the aim of creating biodegradable materials for medical devices clinical appointments with high hemocompatibility we have developed a new polymer product.The basis of this product is plasticized by polyethylene glycol bacterial copolymer of hydroxybutyrate and oxovalerate. A well-known antitbrombotic supplement--acetylsalicylic acid has been added to improve hemocompatibility in the polymer. The results of our studies showed a controlled prolonged separation of acetylsalicylic acid from polymeric material in the blood. We studied in vitro the dynamics of liberation of acetylsalicylic acid from polymeric coatings. It was shown that the concentration of polyethylene glycol and the thickness of the polymer layer can affect the rate of diffusion of acetylsalicylic acid from polymer films.
基金the National Natural Science Foundation of China (20173046)
文摘The title complex, potassium triethylenetetraaminehexaacetatodi [oxo-vanadium (Ⅳ)] hexahydrate K2[V2O2(ttha)]6(H2O), was synthesized in aqueous solution and its crystal structure has been determined by X-ray diffraction. The complex belongs to a triclinic system, space group P?with a = 6.645(1), b = 9.870(2), c = 13.263(3) ? a = 70.68(3), b = 76.27(3), g = 71.66(3), V = 770.5(3) 3, Mr = 808.58, Dc = 1.743 g/cm3, Z = 1, m = 0.968 mm-1, l(MoKa) = 0.71073 and F(000) = 416. The final R = 0.0465 and wR = 0.1091 for 2974 observed diffractions with I ≥ 2s(I). In the complex, the V atom is octahedrally coordinated to the oxo ligand, two N and three O atoms of the triethylenetetraaminehexaacetic (TTHA) ligand. All of the ten chelating sites are coordinated to the two vanadium atoms, and the coordination octahedron is distorted. Each [V2O2(ttha)]2- ion is further connected by the K+ ions through carboxyl groups of TTHA6- ion, forming a two dimensional network structure.
基金supported by the National Natural Science Foundation of China(21173172,21103143,21033006)the Research Fund for the Doctorial Program of Higher Education(20130121130001)the Program for Changjiang Scholars and Innovative Research Team in University(IRT1036)
文摘The catalytic transformation of cellulose into key building-block or platform chemicals such as 5-hydoxymethylfurfural(HMF),levulinic acid,and lactic acid under mild conditions,has attracted much attention in recent years,as these conversions can be operated without consumption of hydrogen or oxygen and thus are more economical compared to the hydrogenolysis or oxidation of cellulose.This review article highlights recent advances in the development of novel catalysts or catalytic processes for the conversion of cellulose and its derived carbohydrates into HMF,levulinic acid,and lactic acid or their esters under inert atmosphere.We also analyze efficient catalytic systems for HMF production,in particular Lewis acids combined with ionic liquid or biphasic systems.For the formations of levulinic and lactic acids or their esters,we focus on the reactions in aqueous and alcohol media catalyzed by multifunctional catalysts that combine the functions of hydrolysis,isomerization,and dehydration-rehydration or retro-aldol reactions.The reaction mechanism for each process will also be discussed to gain insights into the activation of C–O and C–C bonds in the absence of hydrogen or oxygen.
