bluuebunny/crossref_metadata_2025_split huggingface dataset:
Phospholipid Bilayers as Molecular Models for Drug‐Cell Membrana Interactions. The Case of the Antiinflamatory Drug Diclofenac
Authors: Suwalsky Mario , Manrique Marcela , Villena Fernando , Sotomayor Carlos P. 
Published: November 2010

AbstractPhospholipids are amphipatic molecules with long hydrophobic acyl chains and zwitterionic polar heads which assemble into different types of molecular aggregates. The most relevant is the bilayer because of its relation with cell membranes, which are very complex entities. For this reason, simpler molecular models based on phospholipids bilayers are widely used. We have determined the bilayer structure of phospholipids located in the outer and inner monolayers of most cell membranes, and use them as molecular models to study the way different chemicals of biological interest interact with cell membranes. We present the results of our studies on the nonsteroidal anti‐inflammatory drug diclofenac, from which little is known about its effects on human erythrocytes. This report presents the following evidence that diclofenac interacts with the human red cell membrane: a) X‐ray diffraction and fluorescence spectroscopy of phospholipids bilayers show that diclofenac interacts with a class of lipids found in the outer moiety of the erythrocyte membrane; b) in isolated unsealed human erythrocyte membranes the drug induced a disordering effect on the acyl chains of the membrane lipid bilayer; c) in scanning electron microscopy studies on human erythrocytes it was observed that the drug induced morphological changes different from their normal biconcave shape.
Multifunctional Polyesters for Bioartificial Vascular Prostheses
Authors: Theiler Stefan , Mela Petra , Keul Helmut , Möller Martin 
Published: November 2010

AbstractAliphatic polyesters of controlled molecular weight and low molecular weight distribution were prepared via anionic ring‐opening polymerization using a multifunctional star‐shaped initiator. Functionalization results in star‐shaped functional polyesters bearing methacrylate end groups. Novel biodegradable polyester resins were prepared by photochemical crosslinking of the functional polyesters. Three‐dimensional microstructuring via UV replica molding shows the potential of this material as substrate for biomedical devices.
FTIR Investigation of UHMWPE Oxidation Submitted to Accelerated Aging Procedure
Authors: Rocha Magda F. , Mansur Alexandra A. P. , Mansur Herman S. 
Published: November 2010

AbstractIn the present study, an accelerated ageing by oxidative degradation of UHMWPE in hydrogen peroxide solution was performed and the inhibition with ascorbic acid (vitamin C) was analyzed. Both systems were extensively characterized by Fourier Transformed Infrared Spectroscopy (FTIR). Different chemical groups of UHMWPE associated with the degradation reaction were monitored for over 120 days in order to evaluate the possible oxidation mechanisms involved and the inhibitory behavior of vitamin C. The results have provided strong evidence that the oxidation mechanism is rather complex, and 2 stages with their own particular first‐order kinetics reaction patterns have been clearly identified. Furthermore, the vitamin C has proven to be an efficient antioxidant for UHMWPE under the evaluated conditions.
Nanotopography Engineering on Homopolymeric Surfaces Using Cold Plasma Generated Charges
Authors: Manolache Sorin O. , Gutierrez Klinsmann A. , Hall Charles D. 
Published: November 2010

AbstractSummary: Cold plasma as source for charged particles was used to induce nanotopographies on homopolymeric surfaces (nylon 12, PMMA, PMA, etc.). Hydrogen and helium plasmas were successfully used for surface nanoengineering of polymers using inductively coupled or atmospheric pressure non‐equilibrium barrier discharge reactors. AFM analyses reveal the presence of nanotopographies on the treated surfaces. Physical factors control the process below the Tg and chemical factors dominate the process above Tg. Pyrolysis GC/MS analyses have been performed in order to obtain more information about the plasma processes. Cold plasma chemical processes, including charges effects are discussed as tools that open‐up new ways for nanoengineering of the polymers' surfaces with specific functionalities and / or topography. Future nanomanufacturing techniques can generate anti‐scratch, superhydrophobic or superhydrophilic properties on surface of every day use polymeric products by simple and convenient plasma enhanced processes.
Cardanol Based Matrix for Jute Reinforced Pipes
Authors: Campaner Pietro , D'Amico Daniele , Ferri Pierluigi , Longo Luigia , Maffezzoli Alfonso , Stifani Cristina , Tarzia Antonella 
Published: November 2010

AbstractThe aim of this work is the development of composite pipes using renewable resources. The pipes, manufactured by filament winding technology, were obtained using an epoxy resin crosslinked with a cardanol based novolac as matrix and jute fibres as reinforcement. Cardanol is a natural oil extracted from the shell of the cashew (Anacardium occidentale L.) nut. An amount of natural materials higher than 50% by weight was achieved in the final composites. Tensile and parallel plate compression tests were carried out on the composite pipes.
Chitosan Encapsulation of Poly(n‐butyl acrylate‐co‐methyl methacrylate) Particles
Authors: Taweerat Wikanda , Phattanarudee Siriwan 
Published: November 2010

AbstractPoly(n‐butyl acrylate‐co‐methyl methacrylate) particles encapsulated with chitosan were synthesized at 1:1 monomer ratio using potassium persulfate as an initiator. Effect of concentration and molecular weight of chitosan on particle encapsulation process was investigated. Chitosan concentration was varied from 0.5%, 1%, and 1.5% w/v, while molecular weights were 120, 370, and 850 kDa, respectively. The results showed that the particle diameter of the copolymer particles with chitosan encapsulation was increased when the concentration and molecular weight of chitosan were increased. The average particle size and zeta potential were obtained in a range of 144–625 nm and +27 – +47 mV, respectively. TEM micrographs suggested a presence of the chitosan encapsulation layer on the particles.
PMMA‐AES Blends Prepared by in situ Polymerization
Authors: de Carvalho Fabiana Pires , Gonçalves Maria do Carmo , Felisberti Maria Isabel 
Published: November 2010

AbstractBlends of poly(methyl methacrylate) (PMMA) and poly(acrylonitrile‐g‐(ethylene‐co‐propylene‐co‐diene)‐g‐styrene) (AES) were prepared by in situ polymerization. AES, a commercial elastomer obtained by radical copolymerization of styrene and acrylonitrile in the presence of ethylene‐propylene‐diene terpolymer (EPDM), was dissolved in methyl methacrylate and the in situ polymerization was conducted at 60 °C. The blends were characterized by CHN analysis, infrared spectroscopy (FTIR), carbon‐13 nuclear magnetic resonance (13C NMR), dynamic mechanical analysis (DMA) and transmission electron microscopy (TEM). These blends are immiscible and present complex phase behavior. Selective extraction of the blends’ components showed that a fraction of the material is crosslinked and grafting reactions on EPDM chains take place during MMA polymerization. Syndiotactic PMMA was obtained in the presence of AES and this syndiotactic‐specificity increased with increasing amount of AES. The morphology of polymerized specimens showed irregular domains of elastomeric phase and in some cases inclusions of PMMA could be observed.
Dielectric Analysis of Short‐Term and Long‐Term Curing of Novel Photo‐Curing Dental Filling Materials
Authors: Steinhaus Johannes , Frentzen Matthias , Rosentritt Martin , Möginger Bernhard 
Published: November 2010

AbstractHighly glass powder filled photo‐curing dental filling materials based on acrylic resins are used as an alternative for classical amalgam fillings for almost two decades. To improve the performance of the fillings nowadays nano‐particles are introduced in these resins. However, surprisingly less is known about their curing kinetics and how it is affected by the composition of the resin and the kind of the filler. It is shown how the dielectric analysis (DEA) can be used to trace both the short‐term photo‐curing (Figure 1) as well as the long‐term post‐curing of such resins when measuring its ion viscosity. Especially if assisted by other thermo‐analytical methods the DEA allows for a deeper insight in the processes occurring in the dental filling materials. Long‐term measurements over several days using DEA and DMA (dynamic mechanical analysis) exhibit that there are going on significant changes of the properties of the dental material which are relevant for the long‐term performance (Figure 2). The DEA is an easy to handle and cost efficient method to investigate the curing kinetic either for dental composite material engineering as well as for quality insurance purposes.
Notched Ring Test for Measuring Slow Cracking Resistance in Plastics Pipes and Fittings
Authors: Tischler Christian , Kratochvilla Thomas R. , Muschik Heinz , Dragaun Heinz 
Published: November 2010

AbstractIt is known, that the lifetime of polyethylene pipes is essentially limited by slow crack growth (SCG). For state of the art PE materials common SCG testing methods have reached their limits with respect to extension of testing times. A comparatively new method is the Notched Ring Test (NRT) as developed by Choi et al.[1] Pipe rings notched at the inner wall are used. The test is carried out in 80 °C water under constant bending load. The arrangement of the notch at the inner wall reduces testing times using the residual stress of extruded pipes. A disadvantage of this method is that there is no clearly defined failure time because SCG takes place between two phases of creeping. The output of this test is an “on‐set slow cracking time” (crack initiation), obtained by analysis of the displacement curve. In this work it has been shown that the NRT method yields to brittle fracture within acceptable time frames.[2] Methods for data analysis are presented. This test could be very useful applied in research and development for resin evaluation and as a tool in quality control in pipe production for evaluating the process conditions.
Synthesis and complete assignment of NMR data of 20 chalcones
Authors: Hwang Doseok , Hyun Jiye , Jo Geunhyeong , Koh Dongsoo , Lim Yoongho 
Published: November 2010

AbstractChalcones, intermediates in flavonoid biosynthesis, can exhibit antibacterial, antiproliferative, and anti‐inflammatory properties. Chalcones contain two benzene rings and both hydroxylated and methoxylated analogs are frequently produced by hydroxylases and O‐methyltransferases in plant biosynthetic pathways. Assignments of NMR peaks in the spectra of hydroxylated and/or methoxylated chalcones can help in identifying novel chalcone derivatives isolated from natural sources by referencing these data against NMR spectra obtained from known chalcones. We report here the syntheses of 20 chalcones and complete assignments of 1H and 13C NMR spectra. Copyright © 2010 John Wiley & Sons, Ltd.
Generalized plasticity state parameter‐based model for saturated and unsaturated soils. Part II: Unsaturated soil modeling
Authors: Manzanal Diego , Pastor Manuel , Merodo José Antonio Fernández 
Published: November 2010

AbstractThe aim of this paper is to extend the generalized plasticity state parameter‐based model presented in part 1 to reproduce the hydro‐mechanical behavior of unsaturated soils. The proposed model is based on two pairs of stress–strain variables and a suitable hardening law taking into account the bonding—debonding effect of suction and degree of saturation. A generalized state parameter for unsaturated state is proposed to reproduce soil behavior using a single set of material parameters. Generalized plasticity gives a suitable framework to reproduce not only monotonic stress path but also cyclic behavior. The hydraulic hysteresis during a drying—wetting cycle and the void ratio effect on the hydraulic behavior is introduced. Comparison between model simulations and a series of experimental data available, both cohesive and granular, are given to illustrate the accuracy of the enhanced generalized plasticity equation. Copyright © 2010 John Wiley & Sons, Ltd.
Water alternatives—who and what influences public acceptance?
Authors: Dolnicar Sara , Hurlimann Anna 
Published: November 2010

Abstract

Water supports life, society, the environment and the economy, therefore, the task of ensuring a nation's water supply is one of the most fundamental responsibilities of every government. Water management has become a greater challenge due to the increased demand for water as a result of population growth and the impact of climate change on the variability of rainfall. In response, many cities have implemented plans to augment their traditional water supplies (e.g. dams and groundwater) with new or alternative sources (e.g. recycled wastewater and desalinated sea water). Historical evidence suggests that in order for water augmentation projects to be successfully implemented, the support of the general public is required. It is thus critical to understand the factors which influence people's attitudes regarding water‐related matters. The aim of this study is to identify these influencing factors. Results from an empirical study including both qualitative and quantitative components indicate that a number of factors are influential in the public's acceptance of alternative water sources, including research findings, the experience of water shortage, consideration for future generations and news, facts and other publicized information. Notably, politicians and the government were rated by respondents as having a low level of influence. Factors which may determine differences in influence were explored. This revealed a small number of differences for people with low acceptance levels of recycled and desalinated water, and for people with higher levels of education. Systematic differences were identified by comparing the general Australian population with that of Toowoomba, a regional town in Queensland where a referendum on a water recycling project was held. Policy implications are discussed.
Copyright © 2010 John Wiley & Sons, Ltd.
Ski, a modulator of wound healing and scar formation in the rat skin and rabbit ear
Authors: Li Ping , Liu Ping , Xiong Ren‐Ping , Chen Xing‐Yun , Zhao Yan , Lu Wei‐Ping , Liu Xia , Ning Ya‐Lei , Yang Nan , Zhou Yuan‐Guo 
Published: November 2010

AbstractWe recently demonstrated that Ski is a novel wound healing‐related factor that promotes fibroblast proliferation and inhibits collagen secretion. Here, we show that increasing local Ski expression by gene transfer not only significantly accelerated wound healing by relieving inflammation, accelerating re‐epithelialization and increasing formation of granulation tissue, but also reduced scar formation by decreasing collagen production in rat dermal wounds. Similarly, ski gene transfer accelerated wound healing, reduced the protuberant height and volume of scars and increased collagen maturity in a hypertrophic scar model in the rabbit ear. Conversely, reducing Ski expression in the wound by RNA interference resulted in significantly slower wound healing and increased scar area in rat dermal wounds. We demonstrated that these effects of Ski are associated with transforming growth factor‐β‐mediated signalling pathways through both Smad2/3‐dependent and Smad‐independent pathways. Together, our results define a dual role for Ski in promoting wound healing and alleviating scar formation, identifying a new target for therapeutic approaches to preventing scar hyperplasia and accelerating wound healing. Copyright © 2011 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Thermal properties of polypropylene nanocomposites: Effects of carbon nanomaterials and processing
Authors: Radhakrishnan Vinod K. , Zagarola Stephen W. , Davis Edward W. , Davis Virginia A. 
Published: November 2010

AbstractDesign of experiments was used to elucidate the complex interactions that determine nanocomposite properties and enable predictive models for optimization. The thermal properties of nanocomposites containingpolypropylene, single‐walled carbon nanotubes (SWNTs), dodecyl‐functionalized SWNTs, and vapor‐grown carbon fibers were investigated as a function of extrusion temperature, screw speed, and time. The effects of extruder processing conditions on thermal properties was dependent on the fraction of polymer chains stabilized in the interphase, the extent of polymer degradation, and the type of nanomaterial incorporated. Melting and crystallization temperatures were primarily affected by nanomaterial type. However, thermal decomposition temperature was affected significantly by processing conditions and the response wasdependent on the type of nanomaterial incorporated. POLYM. ENG. SCI., 2011. © 2010 Society of Plastics Engineers
Arylamino‐functionalized fluorene‐ and carbazole‐based copolymers: Color‐tuning their CdTe nanocrystal composites from red to white
Authors: Kanelidis Ioannis , Ren Yi , Lesnyak Vladimir , Gasse Jan‐Christoph , Frahm Ronald , Eychmüller Alexander , Holder Elisabeth 
Published: November 2010

AbstractFour alternating arylamino‐functionalized copolymers were synthesized in a Suzuki copolymerization applying 4, 4′‐(2,7‐dibromo‐9H‐fluorene‐9,9‐diyl)dianiline, 4,4′‐(2,7‐dibromo‐9H‐fluorene‐9,9‐diyl)bis(N,N‐diphenylaniline), 4‐(3,6‐dibromo‐9H‐ carbazol‐9‐yl)aniline and 4‐(3,6‐dibromo‐9H‐carbazol‐9‐yl)‐N,N‐diphenylaniline in combination with 2,2′‐(9,9‐dioctyl‐9H‐fluorene‐2,7‐diyl)bis(1,3,2‐dioxaborinane). The resulting novel alternating copolymers were fully characterized. The copolymers revealed blue light emission and wide optical bandgaps of at least 2.93 eV for the fluorene‐based and 3.07 eV for the carbazole‐based polymers. The amino‐functions allow to tie semiconducting CdTe nanocrystals (NCs) and to synthesize a series of composites with CdTe NCs. Moreover, tuning the emission color over a wide range by tying these CdTe NCs results in a facile preparation of organic–inorganic semiconductor composites with emission colors “à la carte.” © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Well‐defined polyolefin/poly(ε‐caprolactone) diblock copolymers: New synthetic strategy and application
Authors: Li Qi‐Zheng , Zhang Guo‐Yi , Chen Jian‐Zhuang , Zhao Qiao‐Ling , Lu Hui‐Chao , Huang Jin , Wei Liu‐He , D'agosto Franck , Boisson Christophe , Ma Zhi 
Published: November 2010

AbstractA new synthetic strategy, the combination of living polymerization of ylides and ring‐opening polymerization (ROP), was successfully used to obtain well‐defined polymethylene‐b‐poly(ε‐caprolactone) (PM‐b‐PCL) diblock copolymers. Two hydroxyl‐terminated polymethylenes (PM‐OH, Mn= 1800 g mol−1 (PDI = 1.18) and Mn = 6400 g mol−1 (PDI = 1.14)) were prepared using living polymerization of dimethylsulfoxonium methylides. Then, such polymers were successfully transformed to PM‐b‐PCL diblock copolymers by using stannous octoate as a catalyst for ROP of ε‐caprolactone. The GPC traces and 1H NMR of PM‐b‐PCL diblock copolymers indicated the successful extension of PCL segment (Mn of PM‐b‐PCL = 5200–10,300 g mol−1; PDI = 1.06–1.13). The thermal properties of the double crystalline diblock copolymers were investigated by differential scanning calorimetry (DSC). The results indicated that the incorporation of crystalline segments of PCL chain effectively influence the crystalline process of PM segments. The low‐density polyethylene (LDPE)/PCL and LDPE/polycarbonate (PC) blends were prepared using PM‐b‐PCL as compatibilizer, respectively. The scanning electron microscopy (SEM) observation on the cryofractured surface of such blend polymers indicates that the PM‐b‐PCL diblock copolymers are effective compatibilizers for LDPE/PCL and LDPE/PC blends. Porous films were fabricated via the breath‐figure method using different concentration of PM‐b‐PCL diblock copolymers in CH2Cl2 under a static humid condition. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Gluconolactone‐derivated polymers: Copolymerization, thermal properties, and their potential use as polymeric surfactants
Authors: Bordegé Vanesa , Muñoz‐bonilla Alexandra , León Orietta , Cuervo‐rodríguez Rocío , Sánchez‐chaves Manuel , Fernández‐García Marta 
Published: November 2010

AbstractStatistical glycopolymers based on gluconolactone have been prepared by classical radical polymerization and followed by 1H NMR in situ. The kinetic behavior of this system in terms of global rate constant has been qualitatively studied. The variation of cumulative feed and copolymer composition with conversion has also been analyzed, showing a diminishment of both as the reaction progresses. The monomer reactivity ratios have been estimated using the Mayo‐Lewis terminal model and extended Kelen–Tüdös equation, being rHEMAG = 1.41 ± 0.06 and rMA = 0.42 ± 0.05. The thermal properties have been examined by differential scanning calorimetry and thermogravimetric analysis. The glass transition and the thermal degradation temperatures of glycopolymers increase as hydrophilic component decreases. In addition, the solution properties of the water‐soluble glycopolymers have been investigated, observing the formation of small micelles. Finally, the potential of these glycopolymers as polymeric surfactants has been proved by the performance of emulsion polymerization of methyl acrylate. The resulting particles are stable and with low polydispersity, decreasing the particle size as the methyl acrylate content increases in the glycopolymer surfactant. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Kinetics studies on the accelerated curing of liquid crystalline epoxy resin/multiwalled carbon nanotube nanocomposites
Authors: Chen Sharon , Hsu Sheng‐Hao , Wu Ming‐Chung , Su Wei Fang 
Published: November 2010

AbstractA new class of nanocomposite has been fabricated from liquid crystalline (LC) epoxy resin of 4,4′‐bis(2,3‐epoxypropoxy) biphenyl (BP), 4,4′‐diamino‐diphenyl sulfone (DDS), and multiwalled carbon nanotubes (CNTs). The surface of the CNTs was functionalized by LC epoxy resin (ef‐CNT). The ef‐CNT can be blended well with the BP that is further cured with an equivalent of DDS to form nanocomposite. We have studied the curing kinetics of this nanocomposite using isothermal and nonisothermal differential scanning calorimetry (DSC). The dependence of the conversion on time can fit into the autocatalytic model before the vitrification, and then it becomes diffusion control process. The reaction rate increases and the activation energy decreases with increasing concentration of the ef‐CNT. At 10 wt % of ef‐CNT, the activation energy of nanocomposite curing is lowered by about 20% when compared with the neat BP/DDS resin. If the ef‐CNT was replaced by thermal‐insulating TiO2 nanorods on the same weight basis, the decrease of activation energy was not observed. The result indicates the accelerating effect on the nanocomposite was raised from the high‐thermal conductivity of CNT and aligned LC epoxy resin. However, at ef‐CNT concentration higher than 2 wt %, the accelerating effect of ef‐CNTs also antedates the vitrification and turns the reaction to diffusion control driven. As the molecular motions are limited, the degree of cure is lowered. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011