bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mussel‐Inspired Coating of Polydopamine Directs Endothelial and Smooth Muscle Cell Fate for Re‐endothelialization of Vascular Devices
Authors: Yang Zhilu , Tu Qiufen , Zhu Ying , Luo Rifang , Li Xin , Xie Yichu , Maitz Manfred F. , Wang Jin , Huang Nan 
Published: July 2012

AbstractPolydopamine (PDAM), a mussel adhesive protein inspired coating that can be easily deposited onto a wide range of metallic, inorganic, and organic materials, gains interest also in the field of biomaterials. In this work, PDAM is applied as coating on 316L stainless steel (SS) stents and the response of cells of the blood vessel wall, human umbilical vein endothelial cell (HUVEC), and human umbilical artery smooth muscle cell (HUASMC) as predictors for re‐endothelialization is tested. It is found that the PDAM‐modified surface significantly enhances HUVEC adhesion, proliferation, and migration, release of nitric oxide (NO), and secretion of prostaglandin I2 (PGI2). Additionally, the PDAM‐modified surface shows a remarkable ability to decrease the adhesion and proliferation of HUASMCs. As a blood‐contacting material, the PDAM tends to improve the hemocompatibility compared with the substrate 316L SS. It is noteworthy that the PDAM coating shows good resistance to the deformation behavior of compression and expansion of a stent. These data suggest the potential of PDAM as a blood‐contacting material for the application in vascular stents or grafts.
Structure–activity relationship for dihydromyricetin as a new natural antioxidant in polymer
Authors: Xin Ming‐liang , Ma Yu‐jie , Xu Kai , Chen Ming‐cai 
Published: July 2012

AbstractDihydromyricetin (DMY), a natural product, was used as antioxidant in ethylene vinyl acetate copolymer (EVA) in our laboratory. Oxidation induction temperature (OIT) of EVA with the antioxidant of DMY and effect of pH on OIT was measured by means of differential scanning calorimeter (DSC). The mechanism on that antioxidation of DMY in EVA is produced on basis of determination of UV–Vis absorption, nuclear magnetic resonance (NMR) and the experiment of reacting the pyrogallic (PA) and DMY, respectively, with the DPPH. The result shows that the ortho‐trihydroxyl group (B ring) in DMY has mainly antioxidative activity and hydroxyl group of 7‐position (A ring) not only displayed reversibility to acidic or alkaline medium but also affected in some extent the antioxidative ability in EVA. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Study on the preparation of Eu(Pht)3Phen/SBA‐15 hybrids and photoluminescence properties of silicone rubber composites with the hybrids
Authors: Xu Shengjie , Ren Wentan , Zhang Yong , Zhang Yinxi 
Published: July 2012

AbstractIn this work, Eu(Pht)3Phen/SBA‐15 hybrids were prepared by solution mixing and their morphologies and structures were characterized by X‐ray diffraction (XRD), scanning electronic microscopy (SEM), nitrogen adsorption–desorption and transmission electronic microscopy (TEM). The results showed that Eu(Pht)3Phen was successfully incorporated into the channels and assembled onto the surface of SBA‐15 and the long range ordered structure of SBA‐15 was preserved. The silicone rubber composites with Eu(Pht)3Phen/SBA‐15 hybrids were obtained by mechanical blending, and their morphologies and photoluminescence properties were studied. The results showed that the photoluminescence intensities of the composites with the hybrids increased as the content of the hybrids increased. The composite with the hybrids showed higher photoluminescence intensity and longer lifetime compared to the silicone rubber compounded with Eu(Pht)3Phen (Eu(Pht)3Phen/silicone rubber composite), Eu(Pht)3Phen and SBA‐15 ([Eu(Pht)3Phen+SBA‐15]/silicone rubber composite). Judd‐Ofelt theory was used to investigate the local environment of Eu3+ ions in the silicone rubber composites. The photoluminescence quantum efficiency of the silicone rubber composite with Eu(Pht)3Phen/SBA‐15 hybrids was calculated to be 31.0%, higher than that of Eu(Pht)3Phen/silicone rubber composite (26.4%) and [Eu(Pht)3Phen+SBA‐15]/silicone rubber composite (25.4%). The enhancement in photoluminescence intensity and increase in lifetime and photoluminescence quantum efficiency could be attributed to the rigid structure of SBA‐15 which reduced the nonradiative transition rate and the improvement of the dispersion of the hybrids in the composites. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Sonochemical synthesis and characterization of amine‐modified graphene/conducting polymer nanocomposites
Authors: Sahoo Sumanta , Bhattacharya Pallab , Hatui Goutam , Ghosh Debasis , Das Chapal Kumar 
Published: July 2012

AbstractThe objective of this work is to modify graphene and study the effect of modification of graphene in thermal and electrical properties of graphene/polypyrrole and graphene/polyaniline nanocomposites. The amine functionalization of graphene was confirmed by Fourier transform infrared spectroscopy and X‐ray photoelectron spectroscopy. The nanocomposites were prepared by insitu oxidative polymerization method using ammonium persulfate as oxidant. Field emission scanning electron microscopy and high‐resolution transmission electron microscopy were used to study the morphology of the nanocomposites which indicates toward the better dispersion of modified graphene within the polymer matrices as compared to unmodified composites. The modification of graphene played an important role in the noticeable improvements in electrical conductivity of the prepared composites. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Polypropylene/polyethylene blends as models for high‐impact propylene–ethylene copolymers, part 1: Interaction between rheology and morphology
Authors: Kock Cornelia , Gahleitner Markus , Schausberger Alois , Ingolic Elisabeth 
Published: July 2012

AbstractIn this work, composition effects on interfacial tension and morphology of binary polyolefin blends were studied using rheology and electron microscopy. The amount of dispersed phase (5–30 wt %) and its type [ethylene–octene copolymer, linear low‐density polyethylene (LLDPE), and high‐density polyethylene] was varied, and the influence of different matrix materials was also studied by using a polypropylene homopolymer and a ethylene–propylene (EP) random copolymer. The particle size distribution of the blends was determined using micrographs from transmission electron microscopy (TEM). A clear matrix effect on the flow behavior could be found from the viscosity curves of the blends. Analyzing the viscosity of the blends applying the logarithmic mixing rule indicated a partial miscibility of the EP random copolymer with low amounts of the LLDPE in the melt. Micrographs from TEM also showed a clear difference in morphology if the base polymer is changed, with PE lamellae growing out of the inclusions or being present directly embedded in the matrix. To verify these findings, the interfacial tension was determined. The applicability of Palierne's emulsion model was found to be limited for such complex systems, whereas Gramespacher–Meissner analysis led to interfacial tensions comparable with those already reported in the literature. The improved compatibility when changing the matrix polymer from the homopolymer to the random copolymer allows the development of multiphase materials with finer phase structure, which will also result in improved mechanical and optical performance. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Improving the oxygen barrier properties of polyethylene terephthalate by graphite nanoplatelets
Authors: Al‐Jabareen Ahmad , Al‐Bustami Hammam , Harel Hannah , Marom Gad 
Published: July 2012

AbstractEnhancement of the oxygen gas barrier properties of polyethylene terephthalate (PET), used in the packaging industry, is the main objective here. For this purpose, nanocomposites of PET containing graphite nanoplatelets (GNPs) were prepared by melt compounding. The effects of the nanocomposites' structural morphology on oxygen gas permeability were analyzed using a range of thermal, microscopic, and mechanical characterization techniques. The investigated nanocomposite films exhibited GNP exfoliated morphology and good mixing with PET, as well as uniform dispersion within the polymer. All nanocomposite films were shown to possess superior oxygen barrier properties and improved thermal and dimensional stability compared with the plain PET films. In the best case, for 1.5 wt % GNP, the oxygen permeation was reduced by more than 99%. The improved barrier properties are attributed to the direct effect of the GNPs and to their induced increase of degree of crystallinity. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Investigation of vegetable‐oil‐based coupling agents for kenaf‐fiber‐reinforced unsaturated polyester composites
Authors: Ren Xiaofeng , Li Kaichang 
Published: July 2012

AbstractKenaf fibers are modified with three novel coupling agents that consist of an isocyanate and acrylated epoxidized soybean oil. The untreated‐kenaf‐UPE (unsaturated polyester) composites and coupling‐agent‐treated‐kenaf‐UPE composites are obtained by a compression molding process. Modifications of kenaf fibers with coupling agents significantly increase mechanical properties, and enhance water resistance of the resulting kenaf‐UPE composites. Characterization of coupling‐agent‐treated‐fibers with Fourier transform infrared spectroscopy reveals that coupling agents are covalently bonded onto kenaf fibers. Improved interfacial adhesion between kenaf fibers and UPE resin is confirmed with scanning electron microscopy. The mechanisms on which the chemical treatments of kenaf fibers improve the mechanical properties and water resistance are discussed. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Deformation and fracture behaviors of vinylester/fly ash composites
Authors: Stocchi A. , Rodríguez E. , Vázquez A. , Bernal C. 
Published: July 2012

AbstractIn this work, the deformation and fracture behaviors of a commercial vinylester resin reinforced with fly ash were investigated. Tensile, compressive, and fracture tests were performed on the matrix and the composites with different ash content. Most composites exhibited improved stiffness, tensile strength, and fracture properties in comparison to the vinylester matrix. From scanning electron microscopic analysis of fracture surfaces, the toughening mechanisms of crack pinning, crack deflection, particle debonding, and localized shear yielding were identified. In addition, the dependence of tensile and compressive modulus and fracture energy toward ash content was adequately fitted by simple models available in the literature. From the results of these models and energy‐dispersive X‐ray spectroscopy analysis, some interaction between vinylester and ash seemed to exist. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Preparation and utilization of microporous molecularly imprinted polymer for sustained release of tetracycline
Authors: Mirzaei Mohammad , Najafabadi Sayed Alireza Hassani , Abdouss Majid , Azodi‐Deilami Saman , Asadi Ebadullah , Hosseini Mohammad Reza Milani , Piramoon Majid 
Published: July 2012

AbstractA polyacrylate tetracycline (TC) selective microporous molecularly imprinted polymer was prepared in three different porogenic solvents (chloroform, acetonitrile, and methanol) via precipitation polymerization, using methacrylic acid monomer, ethylene glycol dimethacrylate crosslinker, and TC as template. In all three solvents this method produced microporous particles in the scale range (200–400 nm), simply, quickly, cleanly, and in good yield. The effect of polarity of porogenic solvents on binding capacity was investigated. The imprinted polymer prepared in chloroform gave much higher binding capacity (KD = 198.6) for TC than the polymers prepared in acetonitrile (KD = 133.2) or methanol (KD = 104.7). The selectivity of imprinted polymers was evaluated by rebinding other structurally similar compounds. The results clearly indicated that the imprinted acrylate polymer exhibits an excellent selectivity toward TC, and has better ability to control the release of TC than the non‐imprinted polymer.© 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Synthesis and characterization of PLA nanocomposites containing nanosilica modified with different organosilanes I. Effect of the organosilanes on the properties of nanocomposites: Macromolecular, morphological, and rheologic characterization
Authors: Basilissi Luca , Silvestro Giuseppe Di , Farina Hermes , Ortenzi Marco Aldo 
Published: July 2012

AbstractPolylactide nanocomposites containing different loadings of nanosilica were prepared by employing bulk ring opening polymerization from lactide. Nanosilica was used as such and after surface treatment with different amounts of two distinct silanes. The effects on the properties of the material were evaluated comparing the samples containing organosilane‐modified nanosilica with poly(lactic acid) (PLA) containing unmodified nanosilica. A standard linear PLA and an industrial “film grade” PLA (PLA Natureworks 4032D) were used as reference. Pure silica tends to decrease the molecular weight of the material, deactivating the catalytic system but when silanes are present on the surface, molecular weights are similar to the ones of standard and industrial PLA. Transmission electron microscopy analysis shows that silanes improve the dispersion of the mineral, while rheologic curves suggest that when silanes are present melt viscosity increases markedly at zero shear and decreases faster as the shear rate increases. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Leptin exacerbates collagen‐induced arthritis via enhancement of Th17 cell response
Authors: Deng Jun , Liu Yang , Yang Min , Wang Shengjun , Zhang Miaojia , Wang Xiaohui , Ko King‐Hung , Hua Zichun , Sun Lingyun , Cao Xuetao , Lu Liwei 
Published: July 2012

AbstractObjectiveTo determine the role of leptin in modulating Th17 cell response and joint inflammation in mice with collagen‐induced arthritis (CIA).MethodsLeptin receptor expression on T cells was examined by polymerase chain reaction (PCR) analysis, immunofluorescence microscopy, and flow cytometry. Effects of leptin on Th17 cell differentiation and proliferation were evaluated by quantitative PCR, carboxyfluorescein diacetate succinimidyl ester proliferation assay, and flow cytometry. Dynamic changes in leptin concentrations in the joint tissue and synovial fluid of mice with CIA were determined by immunohistochemistry analysis and enzyme‐linked immunosorbent assay (ELISA). Arthritis symptoms and joint pathology in mice with CIA were assessed after injection of leptin into the knee joint. Th1 and Th17 cell populations in the spleen, draining lymph nodes, and joint tissue were analyzed by flow cytometry and enzyme‐linked immunospot assay. Interleukin‐17 messenger RNA and protein levels in the joint tissue were measured by PCR analysis and ELISA.ResultsIn culture, leptin treatment significantly increased Th17 cell generation from naive CD4+ T cells. During CIA development, markedly elevated levels of leptin were detected in the joint tissue and synovial fluid. Moreover, injection of leptin into the knee joint of collagen‐immunized mice resulted in an early onset of arthritis and substantially increased the severity of clinical symptoms, accompanied by more pronounced synovial hyperplasia and joint damage. Further examination by immunofluorescence microscopy confirmed the presence of significantly increased numbers of Th17 cells in the joint tissue and draining lymph nodes of leptin‐treated mice with CIA.ConclusionThe results of this study identify a previously undescribed function of leptin in enhancing Th17 cell response and exacerbating joint inflammation in mice with CIA.
Genetic inhibition of fibroblast growth factor receptor 1 in knee cartilage attenuates the degeneration of articular cartilage in adult mice
Authors: Weng Tujun , Yi Lingxian , Huang Junlan , Luo Fengtao , Wen Xuan , Du Xiaolan , Chen Qian , Deng Chuxia , Chen Di , Chen Lin 
Published: July 2012

AbstractObjectiveFibroblast growth factor (FGF) family members are involved in the regulation of articular cartilage homeostasis. The aim of this study was to investigate the function of FGF receptor 1 (FGFR‐1) in the development of osteoarthritis (OA) and its underlying mechanisms.MethodsFGFR‐1 was deleted from the articular chondrocytes of adult mice in a cartilage‐specific and tamoxifen‐inducible manner. Two OA models (aging‐associated spontaneous OA, and destabilization‐induced OA), as well as an antigen‐induced arthritis (AIA) model, were established and tested in Fgfr1‐deficient and wild‐type (WT) mice. Alterations in cartilage structure and the loss of proteoglycan were assessed in the knee joints of mice of either genotype, using these 3 arthritis models. Primary chondrocytes were isolated and the expression of key regulatory molecules was assessed quantitatively. In addition, the effect of an FGFR‐1 inhibitor on human articular chondrocytes was examined.ResultsThe gross morphologic features of Fgfr1‐deficient mice were comparable with those of WT mice at both the postnatal and adult stages. The articular cartilage of 12‐month‐old Fgfr1‐deficient mice displayed greater aggrecan staining compared to 12‐month‐old WT mice. Fgfr1 deficiency conferred resistance to the proteoglycan loss induced by AIA and attenuated the development of cartilage destruction after surgically induced destabilization of the knee joint. The chondroprotective effect of FGFR‐1 inhibition was largely associated with decreased expression of matrix metalloproteinase 13 (MMP‐13) and up‐regulation of FGFR‐3 in mouse and human articular chondrocytes.ConclusionDisruption of FGFR‐1 in adult mouse articular chondrocytes inhibits the progression of cartilage degeneration. Down‐regulation of MMP‐13 expression and up‐regulation of FGFR‐3 levels may contribute to the phenotypic changes observed in Fgfr1‐deficient mice.
Extraction of Cupric Ions with Ionic Liquids Containing Polypyridine‐type Small Molecules or Peripherally Pyridine‐modified Dendrimers
Authors: Su Chung‐Jui , Tang Yi‐Hsuan , Yu Fu‐Lun , Wu Ru‐Rong , Hsu Sodio C. N. , Kao Chai‐Lin , Huang Hsin‐Yi , Chen Po‐Yu 
Published: July 2012

AbstractThe hydrophobic ionic liquid N‐butyl‐N‐methylpyrrolidinium bis((trifluoromethyl)sulfonyl)amide (BMP‐TFSA IL), which contains a series of flexible ionophores of polypyridine‐type small molecules or two rigid ionophores of peripherally pyridine‐modified PAMAM dendrimers, was used to extract cupric ions from aqueous solutions. The polypyridine‐type ionophores show good selectivity toward cupric ions at pH 2. The selectivity is affected by the spacing between the two amino groups. However, the pyridine‐modified dendrimers showed poor selectivity, although their extraction efficiency still depended on the pH of the aqueous solution. The ionic liquids that contained small molecular ionophores and their dendrimer analogs were reused after acid washing or electrochemical reduction. During acid washing, the nitrogen atoms of the ionophores were protonated to release the cupric ions into the aqueous phase, and the copper atoms were deposited onto the electrode surface during the electrochemical reduction accompanied by the regeneration of the ionophores.
Excess molar enthalpies of nitrous oxide‐heptane in the liquid and supercritical regions
Authors: Pittau Barbara , Cabañas Albertina , Pando Concepción , Renuncio Juan A. R. 
Published: July 2012

AbstractThe excess molar enthalpies HEm of {xN2O+(1‐x)C7H16} were measured in the liquid and supercritical region covering the whole concentration range. Mixtures at 308.15 K and 7.64, 9.48 and 12.27 MPa show moderately endothermic and exothermic mixing in the heptane‐rich region and nitrous oxide‐rich region, respectively. The exothermic‐mixing region is confined to a smaller range of x as pressure increases and disappears completely at 308.15 K and 15.00 MPa. Mixtures at 318.15 K and 7.64 and 9.48 MPa show very exothermic mixing. Mixtures at 318.15 K and 12.27 and 15.00 MPa show moderately endothermic and exothermic mixing in the heptane‐rich region and nitrous oxide‐rich region, respectively. The changes observed in the excess enthalpy with temperature and pressure are discussed in terms of liquid‐vapor equilibrium and critical constants for nitrous oxide‐heptane. Excess enthalpies for nitrous oxide‐heptane mixtures are also calculated by means of the Peng‐Robinson equation of state and the resulting HEm values are compared with experiment.
Vapour pressures at several temperatures of binary mixtures of di‐n‐propylether+2‐methyl‐1‐propanol, +2‐butanol, or +2‐methyl‐2‐propanol, and excess functions, at T= 298.15 K. Thermodynamic description according to the ERAS‐model
Authors: Garriga R. , Sánchez F. , Fpérez P. , Gracia M. 
Published: July 2012

AbstractVapour pressures of di‐n‐propylether with 2‐methyl‐1‐propanol, 2‐butanol, and 2‐methyl‐2‐propanol were measured at several temperatures between 278.15 K and 323,15 K by a static method. Excess molar enthalpies and volumes for mixtures of di‐n‐propylether with 2‐methyl‐l‐propanol and 2‐butanol, were also measured at T=298.15 K. Reduction of the vapour pressures to obtain activity coefficients and excess molar Gibbs free energies was carried out by Barker's method. Mixtures containing 2‐butanol and 2‐methyl‐2‐propanol show azeotropy with a minimum boiling temperature. GE, HE, and VE, at 298.15 K, of these mixtures are compared with predictions of the ERAS‐model observing that the model reproduces acceptably the experimental behaviour.
Solid‐liquid equilibria in n‐alkanol+n‐alkane systems. Prediction by several group‐contribution theories
Authors: Hofman T. , Barbés B. , Casanova C. 
Published: July 2012

AbstractSeveral, widely used, group contribution models have been used to predict solid‐liquid equilibria for n‐alcohol+n‐alkane binary mixtures. They are: modified UNIFAC [1], DISQUAC [2, 3], Nitta‐Chao [4] and the Hole Model (HM) [5]. Also a recently reported group contribution model (AssoDis) including association [6] has been taken into account. The results have been compared with experimental data.
Multinuclear high‐pressure NMR investigations of undercooled aqueous solutions of hydrophobic ions
Authors: Bradl S. , Schätz T. , Liegl B. , Lang E. W. 
Published: July 2012

AbstractMultinuclear spin‐lattice relaxation rates, cross‐relaxation rates and self‐diffusion coefficient measurements are reported over wide ranges of temperature, pressure and concentration in undercooled aqueous solutions of tetraalkylammonium bromides. These dissolved organic cations with apolar surface groups provide model systems to investigate the effect of coulombic, hydrophobic and H‐bond interactions upon the solvent and solute dynamics within the random, transient H‐bond network of undercooled water.