Based on the kinetic and thermodynamic equations, a comprehensive mathematical model for the con- tinuous esterification process of polyester polyols was developed, which was carried out in an innovational bub- bling ...Based on the kinetic and thermodynamic equations, a comprehensive mathematical model for the con- tinuous esterification process of polyester polyols was developed, which was carried out in an innovational bub- bling reactive distillation tower (BRDT) at atmospheric pressure. In this new type of reactor, direct esterification between ethylene glycol and adipic acid was accomplished efficiently and rapidly. A bench BRDT with the height of 2 m was applied for the esteriflcation process of l^oly (ethylene adlpate) (P'EA). In the continuous operation, Hn- ear oligomers were discharged from the bottom of the column, while water passed a few column trays and a pack- ing section as a condensation byproduct. The influence of major operating conditions on reactor performance was also simulated. Simulation results were in good agreement with experimental data, providing a strategy for devel- oping and optimizing this process.展开更多
This paper describes a facile in‐situ synthesis of palladium nanoparticles (Pd NPs) on silica gel/polydopamine composite(SiO2/PDA) without any stabilizer or reducing agent. In this approach, palladium ions were a...This paper describes a facile in‐situ synthesis of palladium nanoparticles (Pd NPs) on silica gel/polydopamine composite(SiO2/PDA) without any stabilizer or reducing agent. In this approach, palladium ions were adsorbed on SiO2/PDA surfaces by immersing the PDA‐coated SiO2 particles in a palladium plating bath. Then, they were reduced in situ to Pd nanoclusters by the reducing ability of PDA's N‐containing groups. The structure, morphology, and physicochemical properties of the synthesized nanocomposites were characterized by different analytical techniques such as high‐resolution transmission electron microscopy, field‐emission scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, X‐ray diffraction analysis, X‐ray photoelectron spectroscopy, inductively coupled plasma and Fourier‐transform infrared spectroscopy. The Pd NPs capped by the PDA groups had a strikingly small size(30–40 nm). SiO2/PDA/Pd NPs exhibited high catalytic activ‐ity as a recyclable nanocatalyst in the aerobic oxidation of alcohols. Furthermore, recovery and multiple reuse of the catalyst revealed no detectable activity loss.展开更多
Flexible Polyurethane (PU) foam is the material most widely used among urethanes. The foams were synthesized via the reaction of soy polyol, mixtures of isocyanates MDI:TDI (80:20), in the presence of water (bl...Flexible Polyurethane (PU) foam is the material most widely used among urethanes. The foams were synthesized via the reaction of soy polyol, mixtures of isocyanates MDI:TDI (80:20), in the presence of water (blowing agent) with molding process. This experiment was to analyze the physical properties of soy polyol and elaborate the principle of catalyst within the synthesis. The use of liquid and solid catalyst on the polyol synthesis results in significant cellular morphology and properties of polyurethane foam. It is found that the PU which was synthesized using bentonite catalyst has an irregular form of cell morphology, and it has higher density than using sulphuric acid catalyst.展开更多
Castor oil is used to synthesize phenolic resin modified polyol. Castor oil, phenolic resin were taken in the molar ratio 0.07:0.027 and diethylene glycol (DEG) was also taken in varying hydroxyl numbers to achieve...Castor oil is used to synthesize phenolic resin modified polyol. Castor oil, phenolic resin were taken in the molar ratio 0.07:0.027 and diethylene glycol (DEG) was also taken in varying hydroxyl numbers to achieve chemical modification in the backbone of synthesized polyol. Physico-chemical properties like acid value, OH value and moisture content of the modified polyol were measured. The prepared phenolic resin blended polyol were reacted with 4, 4-methylene diisocyanate and 2, 4-toluene diisocyanate to formulate the two component polyurethane (PU) coatings. Prepared coating is used to study properties such as gel time, surface dry, tack free and hard surface drying times. It was found that phenolic resin and diethyleneglycol used in synthesizing castor oil based modified polyols show the significant changes in physico-chemical properties of synthesized polyols. The variation in physico-chemical properties of synthesized polyol provide the information for desirable curing of polyurethane systems.展开更多
Chemical modification of MWCNTs via oxidation followed by side wall functionalization using polyethylene glycol (PEG) and octadecylamine (ODA), separately, was studied. Different characterization techniques such a...Chemical modification of MWCNTs via oxidation followed by side wall functionalization using polyethylene glycol (PEG) and octadecylamine (ODA), separately, was studied. Different characterization techniques such as FTIR spectrometery, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), X-ray diffraction (XRD), and solubility in different solvents were performed for the oxidized MWCNTs, MWCNTs-PEG and MWCNTs-ODA. The characterization techniques proved the presence of the functional groups on the MWCNTs surface. Thermal gravimetric analysis revealed that nearly 16% (by weight) of the MWCNTs were functionalized with PEG and 39% (by weight) was functionalized with ODA.展开更多
This paper aims to prepare a PVA-GAG-COL composite with polyvinyl alcohol (PVA), glycosaminoglycan (GAG) and collagen (COL) by the method of freeze drying and to investigate the feasibility as a tissue engineering sca...This paper aims to prepare a PVA-GAG-COL composite with polyvinyl alcohol (PVA), glycosaminoglycan (GAG) and collagen (COL) by the method of freeze drying and to investigate the feasibility as a tissue engineering scaffold for tissue or organ repairing. In this study, SEM was used to observe the morphology. Biocompatibility was tested by cell culture with the extracted fluid of composite materials. Different proportional scaffolds could be obtained with different concentrations and alcoholysis degree of PVA. Different proportional scaffolds also had different porous structures. SEM proved that large amount of porous structure could be formed. Biocompatibility test showed that the extracted fluid of composite materials was nontoxic, which could promote the adhesion and proliferation of the fibroblast. Fibroblast could grow on the scaffold normally.A porous scaffold for tissue engineering with high water content can be fabricated by PVA, GAG and COL, which has excellent cell biocompatibility. The porous structure shows potential in tissue engineering and cell culture.展开更多
Affinity membranes are fabricated for boric acid removal by the surface functionalization of microporous polypropylene membrane(MPPM)with lactose-based polyols.The affinity is based on specific complexation between bo...Affinity membranes are fabricated for boric acid removal by the surface functionalization of microporous polypropylene membrane(MPPM)with lactose-based polyols.The affinity is based on specific complexation between boric acid and saccharide polyols.A photoinduced grafting-chemical reaction sequence was used to prepare these affinity membranes.Poly(2-aminoethyl methacrylate hydrochloride)[poly(AEMA)]was grafted on the surfaces of MPPM by UV-induced graft polymerization.Grafting in the membrane pores was visualized by dying the cross-section of poly(AEMA)-grafted MPPM with fluorescein disodium and imaging with confocal laser scanning microscopy.It is concluded that lactose ligands can be covalently immobilized on the external surface and in the pores by the subsequent coupling of poly(AEMA)with lactobionic acid(LA).Physical and chemical properties of the affinity membranes were characterized by field emission scanning electron microscopy and Fourier Transform Infrared/Attenuated Total Refraction spectroscopy(FT-IR/ATR).3-Aminophenyl boric acid(3-APBA)was removed from aqueous solution by a single piece of lactose-functionalized MPPM in a dynamic filtration system.The results show that the 3-APBA removal reaches an optimal efficiency(39.5%)under the alkaline condition(pH9.1),which can be improved by increasing the immobilization density of LA.Regeneration of these affinity membranes can be easily realized through acid-base washing because the complexation of boric acid and saccharide polyol is reversible.展开更多
The preparation of polymer-anticancer drug conjugates is an effective way to improve the efficacy and decrease the toxicity of anticancer drugs. Polymer-drug conjugates, which were made by combining a suitable polymer...The preparation of polymer-anticancer drug conjugates is an effective way to improve the efficacy and decrease the toxicity of anticancer drugs. Polymer-drug conjugates, which were made by combining a suitable polymeric carrier, a biodegradable linker and a bioactive anticancer agent, could form the basis of a new generation of anticancer agents. Poly (L-glutamic acid)- paclitaxel conjugate is a polymer-drug conjugate that links anticancer agent paclitaxel (PTX) to poly (L-glutamic acid) (PG). PG-PTX conjugate can improve the anticancer activity, enhance the safety and efficacy, and improve the pharmacokinetic properties of PTX. Therefore, the application of PG-PTX facilitates the clinical therapy of a variety of human cancers.展开更多
b型流行性感冒嗜血杆菌(Haemophilus Influenzae Type B,Hib)感染,是全球性的公共卫生问题,主要引起儿童肺炎和脑膜炎,严重危害儿童的健康。Hib疫苗的诞生为Hib感染性疾病的预防开辟了一条新的道路。现对Hib结合疫苗的多聚核糖基核糖醇...b型流行性感冒嗜血杆菌(Haemophilus Influenzae Type B,Hib)感染,是全球性的公共卫生问题,主要引起儿童肺炎和脑膜炎,严重危害儿童的健康。Hib疫苗的诞生为Hib感染性疾病的预防开辟了一条新的道路。现对Hib结合疫苗的多聚核糖基核糖醇磷酸盐糖链、载体蛋白的种类和特点、不同Hib结合疫苗的免疫原性和安全性,以及联合疫苗的发展作了综述,以期为预防接种和临床操作提供参考。展开更多
A series of ABA triblock copolymers of poly(?-(2-methoxy ethoxy)esteryl-glutamate)-block-poly(ethylene glycol)-blockpoly(?-(2-methoxy ethoxy)esteryl-glutamate) with poly(ethylene glycol) as middle hydrophilic B block ...A series of ABA triblock copolymers of poly(?-(2-methoxy ethoxy)esteryl-glutamate)-block-poly(ethylene glycol)-blockpoly(?-(2-methoxy ethoxy)esteryl-glutamate) with poly(ethylene glycol) as middle hydrophilic B block and oligo(ethylene glycol)-functionalized polyglutamate(poly-L-EG2Glu) as terminal A blocks were prepared via ring-opening polymerization of EG2 Glu N-carboxyanhydride(NCA). The resulting P(EG2Glu)-b-PEG-b-P(EG2Glu) triblocks can spontaneously form hydrogels in water. The intermolecular hydrogen bonding interactions between polypeptides blocks were responsible for the formation of gel network structure. These hydrogels displayed shear-thinning and rapid recovery properties, which endowed them potential application as injectable drug delivery system. The mechanical strength of hydrogels can be modulated by copolymer composition, molecular weight and concentrations. Also, it was found that the hydrogels' strength decreased with temperature due to dehydration of polypeptide segments. Atomic force microscopy and scanning electron microscopy images revealed that these hydrogels were formed through micelle packing mechanism. Circular dichroism and Fourier transform infrared spectroscopy characterizations suggested the poly-L-EG2 Glu block adopted mixed conformation. A preliminary assessment of drug release in vitro demonstrated the hydrogels can offer a sustained release of doxorubicin(DOX) and the release rate could be controlled by varying chemical composition.展开更多
Objective: To evaluate the efficacy and safety of the interventional techniques in the treatment of renal vascular injury. Methods: A total of 16 patients with renal vascular injuries were treated by superselective ...Objective: To evaluate the efficacy and safety of the interventional techniques in the treatment of renal vascular injury. Methods: A total of 16 patients with renal vascular injuries were treated by superselective arterial embolization. The renal injuries resulted from renal biopsy in 7 patients, endovascular intervention in 2, percutaneous puncture and pyelostomy in 2, local resection of renal tumor in 1 and trauma in 4. With regards to clinical manifestations, there was hemorrhagic shock in 8 patients, severe flank pain in 14, and hematuria in 14. CT and ultrasonography confirmed that 15 patients had perirenal hematoma. The embolization was performed with microcoils in 13 and standard stainless steel coils in 3 patients, associated with polyvinyl alcohol particles (PVA) in 9, and gelfoam particles in 6 cases. Results: Renal angiogram revealed arterlovenous fistula in renal parenchyma in 9 cases, pseudoaneurysm in 3 and extravasation of contrast media in 4. The arterial embolization was successful in all 16 cases in a single session. The angiography at the end of therapy showed that abnormal vessels had disappeared without other major intrarenal arterial branch occlusion. In 13 patients with hemodynamical compromise, blood loss-related symptoms were immediately relieved after blood transfusion. In 14 patients with severe flank pain, the pain was progressively relieved. Hematuria ceased in 14 patients 2-14 days after the embolization procedures. The renal function was impaired after the procedure in 6 cases, in which preoperative renal insufficiency was exacerbated in 3 and developed new renal dysfunction in 3, 2 of whom received hemodialysis. The ultrasonography showed that perirenal hematoma was gradually absorbed within 2-6 months after the procedure. All patients were followed up in 6-78 months (mean, 48 months). Six patients died of primary diseases (5 cases of renal failure and multiple organ failure and l case of malignant tumor). Ten patients survived without bleeding and further intervention. The deterioration of renal function did not occur and the serum creatinine and blood urea were in normal range. Conclusion: Transcatheter selective renal arterial embolization is a safe and effective method in the treatment of renal vascular injuries.展开更多
基金Supported by the National Natural Science Foundation of China (21176070).
文摘Based on the kinetic and thermodynamic equations, a comprehensive mathematical model for the con- tinuous esterification process of polyester polyols was developed, which was carried out in an innovational bub- bling reactive distillation tower (BRDT) at atmospheric pressure. In this new type of reactor, direct esterification between ethylene glycol and adipic acid was accomplished efficiently and rapidly. A bench BRDT with the height of 2 m was applied for the esteriflcation process of l^oly (ethylene adlpate) (P'EA). In the continuous operation, Hn- ear oligomers were discharged from the bottom of the column, while water passed a few column trays and a pack- ing section as a condensation byproduct. The influence of major operating conditions on reactor performance was also simulated. Simulation results were in good agreement with experimental data, providing a strategy for devel- oping and optimizing this process.
基金Payame Noor University (PNU) for partial support of this work
文摘This paper describes a facile in‐situ synthesis of palladium nanoparticles (Pd NPs) on silica gel/polydopamine composite(SiO2/PDA) without any stabilizer or reducing agent. In this approach, palladium ions were adsorbed on SiO2/PDA surfaces by immersing the PDA‐coated SiO2 particles in a palladium plating bath. Then, they were reduced in situ to Pd nanoclusters by the reducing ability of PDA's N‐containing groups. The structure, morphology, and physicochemical properties of the synthesized nanocomposites were characterized by different analytical techniques such as high‐resolution transmission electron microscopy, field‐emission scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, X‐ray diffraction analysis, X‐ray photoelectron spectroscopy, inductively coupled plasma and Fourier‐transform infrared spectroscopy. The Pd NPs capped by the PDA groups had a strikingly small size(30–40 nm). SiO2/PDA/Pd NPs exhibited high catalytic activ‐ity as a recyclable nanocatalyst in the aerobic oxidation of alcohols. Furthermore, recovery and multiple reuse of the catalyst revealed no detectable activity loss.
文摘Flexible Polyurethane (PU) foam is the material most widely used among urethanes. The foams were synthesized via the reaction of soy polyol, mixtures of isocyanates MDI:TDI (80:20), in the presence of water (blowing agent) with molding process. This experiment was to analyze the physical properties of soy polyol and elaborate the principle of catalyst within the synthesis. The use of liquid and solid catalyst on the polyol synthesis results in significant cellular morphology and properties of polyurethane foam. It is found that the PU which was synthesized using bentonite catalyst has an irregular form of cell morphology, and it has higher density than using sulphuric acid catalyst.
文摘Castor oil is used to synthesize phenolic resin modified polyol. Castor oil, phenolic resin were taken in the molar ratio 0.07:0.027 and diethylene glycol (DEG) was also taken in varying hydroxyl numbers to achieve chemical modification in the backbone of synthesized polyol. Physico-chemical properties like acid value, OH value and moisture content of the modified polyol were measured. The prepared phenolic resin blended polyol were reacted with 4, 4-methylene diisocyanate and 2, 4-toluene diisocyanate to formulate the two component polyurethane (PU) coatings. Prepared coating is used to study properties such as gel time, surface dry, tack free and hard surface drying times. It was found that phenolic resin and diethyleneglycol used in synthesizing castor oil based modified polyols show the significant changes in physico-chemical properties of synthesized polyols. The variation in physico-chemical properties of synthesized polyol provide the information for desirable curing of polyurethane systems.
文摘Chemical modification of MWCNTs via oxidation followed by side wall functionalization using polyethylene glycol (PEG) and octadecylamine (ODA), separately, was studied. Different characterization techniques such as FTIR spectrometery, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), X-ray diffraction (XRD), and solubility in different solvents were performed for the oxidized MWCNTs, MWCNTs-PEG and MWCNTs-ODA. The characterization techniques proved the presence of the functional groups on the MWCNTs surface. Thermal gravimetric analysis revealed that nearly 16% (by weight) of the MWCNTs were functionalized with PEG and 39% (by weight) was functionalized with ODA.
基金National High-tech Reasearch and Development Program of China(863 Program)grant number:2077AA09Z436+1 种基金Guangdong Project '211'grant number:50621030
文摘This paper aims to prepare a PVA-GAG-COL composite with polyvinyl alcohol (PVA), glycosaminoglycan (GAG) and collagen (COL) by the method of freeze drying and to investigate the feasibility as a tissue engineering scaffold for tissue or organ repairing. In this study, SEM was used to observe the morphology. Biocompatibility was tested by cell culture with the extracted fluid of composite materials. Different proportional scaffolds could be obtained with different concentrations and alcoholysis degree of PVA. Different proportional scaffolds also had different porous structures. SEM proved that large amount of porous structure could be formed. Biocompatibility test showed that the extracted fluid of composite materials was nontoxic, which could promote the adhesion and proliferation of the fibroblast. Fibroblast could grow on the scaffold normally.A porous scaffold for tissue engineering with high water content can be fabricated by PVA, GAG and COL, which has excellent cell biocompatibility. The porous structure shows potential in tissue engineering and cell culture.
基金Supported by the National Natural Science Foundation of China(50933006)the National Basic Research Program of China(2009CB623401)
文摘Affinity membranes are fabricated for boric acid removal by the surface functionalization of microporous polypropylene membrane(MPPM)with lactose-based polyols.The affinity is based on specific complexation between boric acid and saccharide polyols.A photoinduced grafting-chemical reaction sequence was used to prepare these affinity membranes.Poly(2-aminoethyl methacrylate hydrochloride)[poly(AEMA)]was grafted on the surfaces of MPPM by UV-induced graft polymerization.Grafting in the membrane pores was visualized by dying the cross-section of poly(AEMA)-grafted MPPM with fluorescein disodium and imaging with confocal laser scanning microscopy.It is concluded that lactose ligands can be covalently immobilized on the external surface and in the pores by the subsequent coupling of poly(AEMA)with lactobionic acid(LA).Physical and chemical properties of the affinity membranes were characterized by field emission scanning electron microscopy and Fourier Transform Infrared/Attenuated Total Refraction spectroscopy(FT-IR/ATR).3-Aminophenyl boric acid(3-APBA)was removed from aqueous solution by a single piece of lactose-functionalized MPPM in a dynamic filtration system.The results show that the 3-APBA removal reaches an optimal efficiency(39.5%)under the alkaline condition(pH9.1),which can be improved by increasing the immobilization density of LA.Regeneration of these affinity membranes can be easily realized through acid-base washing because the complexation of boric acid and saccharide polyol is reversible.
基金National Key Technologies R&D Program for New Drugs(Grant No.2009ZX09301-002,2009ZX09304-004).
文摘The preparation of polymer-anticancer drug conjugates is an effective way to improve the efficacy and decrease the toxicity of anticancer drugs. Polymer-drug conjugates, which were made by combining a suitable polymeric carrier, a biodegradable linker and a bioactive anticancer agent, could form the basis of a new generation of anticancer agents. Poly (L-glutamic acid)- paclitaxel conjugate is a polymer-drug conjugate that links anticancer agent paclitaxel (PTX) to poly (L-glutamic acid) (PG). PG-PTX conjugate can improve the anticancer activity, enhance the safety and efficacy, and improve the pharmacokinetic properties of PTX. Therefore, the application of PG-PTX facilitates the clinical therapy of a variety of human cancers.
文摘b型流行性感冒嗜血杆菌(Haemophilus Influenzae Type B,Hib)感染,是全球性的公共卫生问题,主要引起儿童肺炎和脑膜炎,严重危害儿童的健康。Hib疫苗的诞生为Hib感染性疾病的预防开辟了一条新的道路。现对Hib结合疫苗的多聚核糖基核糖醇磷酸盐糖链、载体蛋白的种类和特点、不同Hib结合疫苗的免疫原性和安全性,以及联合疫苗的发展作了综述,以期为预防接种和临床操作提供参考。
基金financially supported by the National Natural Science Foundation of China for Distinguished Young Scholar(51225306)the CAS-CSIRO Cooperative Research Program(GJHZ1408)
文摘A series of ABA triblock copolymers of poly(?-(2-methoxy ethoxy)esteryl-glutamate)-block-poly(ethylene glycol)-blockpoly(?-(2-methoxy ethoxy)esteryl-glutamate) with poly(ethylene glycol) as middle hydrophilic B block and oligo(ethylene glycol)-functionalized polyglutamate(poly-L-EG2Glu) as terminal A blocks were prepared via ring-opening polymerization of EG2 Glu N-carboxyanhydride(NCA). The resulting P(EG2Glu)-b-PEG-b-P(EG2Glu) triblocks can spontaneously form hydrogels in water. The intermolecular hydrogen bonding interactions between polypeptides blocks were responsible for the formation of gel network structure. These hydrogels displayed shear-thinning and rapid recovery properties, which endowed them potential application as injectable drug delivery system. The mechanical strength of hydrogels can be modulated by copolymer composition, molecular weight and concentrations. Also, it was found that the hydrogels' strength decreased with temperature due to dehydration of polypeptide segments. Atomic force microscopy and scanning electron microscopy images revealed that these hydrogels were formed through micelle packing mechanism. Circular dichroism and Fourier transform infrared spectroscopy characterizations suggested the poly-L-EG2 Glu block adopted mixed conformation. A preliminary assessment of drug release in vitro demonstrated the hydrogels can offer a sustained release of doxorubicin(DOX) and the release rate could be controlled by varying chemical composition.
文摘Objective: To evaluate the efficacy and safety of the interventional techniques in the treatment of renal vascular injury. Methods: A total of 16 patients with renal vascular injuries were treated by superselective arterial embolization. The renal injuries resulted from renal biopsy in 7 patients, endovascular intervention in 2, percutaneous puncture and pyelostomy in 2, local resection of renal tumor in 1 and trauma in 4. With regards to clinical manifestations, there was hemorrhagic shock in 8 patients, severe flank pain in 14, and hematuria in 14. CT and ultrasonography confirmed that 15 patients had perirenal hematoma. The embolization was performed with microcoils in 13 and standard stainless steel coils in 3 patients, associated with polyvinyl alcohol particles (PVA) in 9, and gelfoam particles in 6 cases. Results: Renal angiogram revealed arterlovenous fistula in renal parenchyma in 9 cases, pseudoaneurysm in 3 and extravasation of contrast media in 4. The arterial embolization was successful in all 16 cases in a single session. The angiography at the end of therapy showed that abnormal vessels had disappeared without other major intrarenal arterial branch occlusion. In 13 patients with hemodynamical compromise, blood loss-related symptoms were immediately relieved after blood transfusion. In 14 patients with severe flank pain, the pain was progressively relieved. Hematuria ceased in 14 patients 2-14 days after the embolization procedures. The renal function was impaired after the procedure in 6 cases, in which preoperative renal insufficiency was exacerbated in 3 and developed new renal dysfunction in 3, 2 of whom received hemodialysis. The ultrasonography showed that perirenal hematoma was gradually absorbed within 2-6 months after the procedure. All patients were followed up in 6-78 months (mean, 48 months). Six patients died of primary diseases (5 cases of renal failure and multiple organ failure and l case of malignant tumor). Ten patients survived without bleeding and further intervention. The deterioration of renal function did not occur and the serum creatinine and blood urea were in normal range. Conclusion: Transcatheter selective renal arterial embolization is a safe and effective method in the treatment of renal vascular injuries.