bluuebunny/crossref_metadata_2025 huggingface dataset:
Silica‐Supported Zirconium Complexes and their Polyoligosilsesquioxane Analogues in the Transesterification of Acrylates: Part 2. Activity, Recycling and Regeneration
Authors: Salinier Valérie , Niccolai Gerald P. , Dufaud Véronique , Basset Jean‐Marie
Published: September 2009

The catalytic activity of both supported and soluble molecular zirconium complexes was studied in the transesterification reaction of ethyl acrylate by butanol. Two series of catalysts were employed: three well defined silica‐supported acetylacetonate and n‐butoxy zirconium(IV) complexes linked to the surface by one or three siloxane bonds, (SiO)Zr(acac)3 (1) (SiO)3Zr(acac) (2) and (SiO)3Zr(O‐n‐Bu) (3), and their soluble polyoligosilsesquioxy analogues (c‐C5H9)7Si8O12(CH3)2Zr(acac)3 (1′), (c‐C5H9)7Si7O12Zr(acac) (2′), and (c‐C5H9)7Si7O12Zr(O‐n‐Bu) (3′). The reactivity of these complexes were compared to relevant molecular catalysts [zirconium tetraacetylacetonate, Zr(acac)4 and zirconium tetra‐n‐butoxide, Zr(O‐n‐Bu)4]. Strong activity relationships between the silica‐supported complexes and their polyoligosilsesquioxane analogues were established. Acetylacetonate complexes were found to be far superior to alkoxide complexes. The monopodal complexes 1 and 1′ were found to be the most active in their respective series. Studies on the recycling of the heterogeneous catalysts showed significant degradation of activity for the acetylacetonate complexes (1 and 2) but not for the less active tripodal alkoxide catalyst, 3. Two factors are thought to contribute to the deactivation of catalyst: the lixivation of zirconium by cleavage of surface siloxide bonds and exchange reactions between acetylacetonate ligands and alcohols in the substrate/product solution. It was shown that the addition of acetylacetone to the low activity catalyst Zr(O‐n‐Bu)4 produced a system that was as active as Zr(acac)4. The applicability of ligand addition to heterogeneous systems was then studied. The addition of acetylacetone to the low activity solid catalyst 3 produced a highly active catalyst and the addition of a stoichiometric quantity of acetylacetone at each successive batch catalytic run greatly reduced catalyst deactivation for the highly active catalyst 1.
Highly Stereoselective Halocyclopropanation of α,β‐Unsaturated Amides
Authors: Concellón José M. , Rodríguez‐Solla Humberto , Blanco Elena G. , Villa‐García María A. , Alvaredo Noemí , García‐Granda Santiago , Díaz M. Rosario
Published: September 2009

A convenient highly stereoselective synthesis of chloro‐ and bromocyclopropanamides from di‐ tri‐ or tetrasubstituted (E)‐ or (Z)‐α,β‐unsaturated amides with total or high stereoselectivity promoted by chromium dichloride or dibromide is described. The transformation of chlorocyclopropanamides into the corresponding ketones or amines is also reported. A mechanism to explain these transformations is proposed.
First Heterogeneous Ligand‐ and Salt‐Free Larock Indole Synthesis
Authors: Batail Nelly , Bendjeriou Anissa , Lomberget Thierry , Barret Roland , Dufaud Véronique , Djakovitch Laurent
Published: September 2009

A new ligand‐ and salt‐free procedure using heterogeneous palladium catalysts for the Larock indole and benzofuran synthesis is reported. After optimisation of the reaction conditions, good to high isolated yields have been achieved for a variety of structures. Recycling studies have shown that the palladium catalysts can be readily recovered and reused. Reactions and recovery of the palladium catalysts can be carried out in the presence of air, without any particular precaution.
Association between methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism and age of onset in schizophrenia
Authors: Vares Maria , Saetre Peter , Deng Hong , Cai Guiqing , Liu Xiehe , Hansen Thomas , Rasmussen Henrik B. , Werge Thomas , Melle Ingrid , Djurovic Srdjan , Andreassen Ole A. , Agartz Ingrid , Hall Håkan , Terenius Lars , Jönsson Erik G.
Published: September 2009

Different lines of evidence indicate that methylenetetrahydrofolate reductase (MTHFR) functional gene polymorphisms, causative in aberrant folate–homocysteine metabolism, are associated with increased vulnerability to several heritable developmental disorders. Opposing views are expressed considering the possible association between MTHFR and susceptibility for schizophrenia. In order to evaluate if age of onset could explain some of this discrepancy we investigated the relationship between two functional MTHFR gene polymorphisms and age at onset in this disorder. Scandinavian patients (n = 820) diagnosed with schizophrenia, schizoaffective disorder, and schizophreniform disorder were investigated. Two functional MTHFR single nucleotide polymorphisms (SNPs; rs1801131 and rs1801133) were genotyped and the effect of MTHFR polymorphisms on the age of onset was examined with survival analysis. In an attempt to replicate the findings from the Scandinavian sample, the association between rs1801133 and age at onset was also analyzed in Chinese high‐risk families, with two or more affected siblings (n = 243). Among the Scandinavian patients the functional MTHFR SNP rs1801133 (C677T) significantly affected age at onset of schizophrenia in a dose‐dependent manner (P = 0.0015), with lower age of onset with increasing numbers of the mutant T‐allele. There was no evidence of rs1801131 (A1298C) affecting age of onset in schizophrenia. Within the Chinese high‐risk families carriers of the MTHFR 677T allele showed earlier age at onset than siblings being homozygous for the wild‐type allele (P = 0.008). The MTHFR C677T polymorphism may play a role as a modifying factor for age of onset in schizophrenia. © 2009 Wiley‐Liss, Inc.
The association of the dopamine transporter gene and the dopamine receptor 2 gene with delirium, a meta‐analysis
Authors: van Munster Barbara C. , de Rooij Sophia E.J.A. , Yazdanpanah Mojgan , Tienari Pentti J. , Pitkälä Kaisu H. , Osse Robert J. , Adamis Dimitrios , Smit Orla , van der Steen Marijke S. , van Houten Miriam , Rahkonen Terhi , Sulkava Raimo , Laurila Jouko V. , Strandberg Timo E. , Tulen Joke H.M. , Zwang Louwerens , MacDonald Alastair J.D. , Treloar Adrian , Sijbrands Eric J.G. , Zwinderman Aeilko H. , Korevaar Johanna C.
Published: September 2009

Delirium is the most common neuropsychiatric syndrome in elderly ill patients. Previously, associations between delirium and the dopamine transporter gene (solute carrier family 6, member 3 (SLC6A3)) and dopamine receptor 2 gene (DRD2) were found. The aim of this study was to validate whether markers of the SLC6A3 and DRD2 genes are were associated with delirium in independent populations. Six European populations collected DNA of older delirious patients. Associations were determined per population and results were combined in a meta‐analysis. In total 820 medical inpatients, 185 cardiac surgery patients, 134 non‐cardiac surgery patients and 502 population‐based elderly subjects were included. Mean age was 82 years (SD 7.5 years), 598 (36%) were male, 665 (41%) had pre‐existing cognitive impairment, and 558 (34%) experienced delirium. The SLC6A3 rs393795 homozygous AA genotype was more frequent in patients without delirium in all populations. The meta‐analysis showed an Odds Ratio (OR) for delirium of 0.4 (95% confidence interval (C.I.) 0.2–0.6, P = 0.0003) for subjects with AA genotype compared to the AG and GG genotypes. SLC6A3 marker rs1042098 showed no association with delirium. In meta‐analysis the DRD2 rs6276 homozygous GG genotype showed an OR of 0.8 for delirium (95% C.I. 0.6–1.1, P = 0.24). When subjects were stratified for cognitive status the rs6276 GG genotype showed ORs of 0.6 (95% C.I. 0.4–1.0, P = 0.06) and 0.8 (95% C.I. 0.5–1.5, P = 0.51) for delirium in patients with and without cognitive impairment, respectively. In independent cohorts, a variation in the SLC6A3 gene and possibly the DRD2 gene were found to protect for delirium. © 2009 Wiley‐Liss, Inc.
Methods on erg9 gene deletion in Schizosaccharomyces pombe
Authors: Cheng Bing , Yuan Qi‐peng , Sun Xin‐xiao , Li Wen‐jin
Published: September 2009

Gene modification to key enzymes in biosynthesis pathway becomes familiar technology which can increase efficiency of industrial strains. In the current study, we established a desirable deletion approach based on homologous recombination. It was simple and available for spn5 gene deletion. Also, four kinds of erg9 gene deletion cassettes were constructed in similar manner. The lengths of flanking sequences for homologous integration were from 59 bp to more than 1 Kb, and three selective markers (G418, Zeocin and LEU2) were employed in these cassettes. However, Δerg9 mutant was not obtained in this work. The possible reason is that erg9 gene is an essential gene and a single copy in its chromosome. Deficiency of erg9 gene resulted in nonviability to the cells. In addition, LEU2 marker caused unspecific integration and the difficulty of screening mutants is increased during deletion procedures. This work provides important evidence to modify industrial strains by using deletion technologies. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd.
Solar membrane natural gas steam‐reforming process: evaluation of reactor performance
Authors: De Falco M. , Basile A. , Gallucci F.
Published: September 2009

In this work, the performance of an innovative plant for efficient hydrogen production using solar energy for the process heat duty requirements has been evaluated via a detailed 2D model. The steam‐reforming reactor consists of a bundle of coaxial double tubes assembled in a shell. The annular section of each tube is the reaction zone in which Ni‐based catalyst pellets are packed, whereas the inner tube is a dense Pd‐based selective membrane that is able to remove hydrogen from the reaction zone. By coupling reaction and hydrogen separation, equilibrium constrains inside the reactor are circumvented and high methane conversions at relatively low temperatures are achieved. The heat needed for the steam‐reforming reaction at this low operating temperature can be supplied by using a molten salt stream, heated up to 550 °C by a parabolic mirror solar plant, as heating fluid. The effects on membrane reactor performance of some operating conditions, as gas mixture residence time, reaction pressure and steam‐to‐carbon ratio, are assessed together with the enhancement of methane conversion with respect to the traditional process, evaluated in the range 40.5–130.9% at the same operating conditions. Moreover, owing to the use of a solar source for chemical process heat duty requirements, the greenhouse gases (GHG) reduction is estimated to be in the range 33–67%. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd.
Steered molecular dynamics simulation of the detaching process of two parallel surfaces glued together by a single polyethylene chain
Authors: Wang Yu , Zhang Linxi , Cheng Jun
Published: September 2009

The detaching process of two parallel surfaces glued together by a single polyethylene chain in vacuo was investigated with a steered molecular dynamics method. Various statistical properties were analyzed in detail, including the mean‐square end‐to‐end distance; parallel and perpendicular mean‐square radii of gyration; shape factor; segment density distribution; average percentages of the microstructure of the chain of the tail, train, bridge, and loop; average surface adsorption energy; average total energy; and average pulling force (〈f〉). All these properties depended strongly on the pulling velocity (v). There existed a peak in the curve of 〈f〉 as a function of the detaching distance. Further, the relation between the maximum value of 〈f〉 and v showed three distinctive regions: a region of weak dependence at v < 10−2 Å/ps, a region of strong dependence at 10−2 Å/ps < v < 6.50 Å/ps, and a region of weak dependence at v > 6.50 Å/ps. These investigations may provide some insight into the microcosmic principle of the failure process of polymeric adhesives. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Investigation on the mechanical performances of ternary nylon 6/SEBS elastomer/nano‐SiO2 hybrid composites with controlled morphology
Authors: Zhang Baoqing , Wong Julia Shuk‐Ping , Shi Dean , Yam Richard Ching‐Man , Li Robert Kwok‐Yiu
Published: September 2009

The distribution of maleated styrene‐hydrogenated butadiene‐styrene (mSEBS) elastomer and nano‐SiO2 in nylon 6 matrix was controlled by varying the blending procedure. Nano‐SiO2 particles with different surface properties (hydrophilic versus hydrophobic) were adopted to adjust their interactions with other components. Two different structures, separate dispersion of nano‐SiO2 and elastomer particles as well as encapsulation of nano‐SiO2 fillers by the elastomer, were obtained. The structures were confirmed through scanning electron microscope (SEM) investigation. The mechanical measurement results showed that the microstructure and the interactions among the components had dramatic influences on the final mechanical properties, especially Izod fracture toughness, for the ternary nanocomposites. The nanocomposites containing hydrophilic nano‐SiO2 had better mechanical performances compared with the composites filled with hydrophobic SiO2 when they were in the same microstructure. The nanocomposites with separate dispersion structure showed higher stiffness compared with those of encapsulation type. However, the separately dispersed nano‐SiO2 particles restricted the cavitation of elastomer phases that led to low toughening effectiveness. The difference of cavitation intensity for elastomer phase was revealed by SEM investigation on the facture surfaces for the nanocomposites with the two different microstructures. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Improvement of permeation performance of polyethersulfone (PES) ultrafiltration membranes via addition of Tween‐20
Authors: Amirilargani Mohammad , Saljoughi Ehsan , Mohammadi Toraj
Published: September 2009

In this study, effects of Tween‐20 (polyoxyethylene sorbitan monolaurate) as a variable surfactant additive on morphology, permeation performance and antifouling properties of asymmetric polyethersulfone (PES) membranes were investigated. The membranes prepared from PES/polyethylene glycol (PEG)/N,N‐dimethylformamide (DMF) system via phase inversion induced by immersion precipitation in water coagulation bath. The membranes performances were evaluated using ultrafiltration (UF) experiments. The scanning electron microscope and atomic force microscopy analysis were performed to investigate the membrane morphology. The obtained results indicate that by increasing the concentration of Tween‐20, the membrane morphology changes slowly from thin finger‐like structure with spongy structure to long and wide finger‐like structure with some macrovoids. Addition of surfactant to the casting solution increases the porosity of the membrane sublayer. It was found out that the rejection ratio of Bovine serum albumin (BSA) decreases, while the flux recovery ratio remarkably increases and the degree of irreversible fouling decreases. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Microstructure determination of methyl methacrylate‐N‐arylsubstituted itaconimide copolymers by NMR spectroscopy
Authors: Chauhan Rashmi , Choudhary Veena
Published: September 2009

This article describes the homopolymerization and copolymerization of methyl methacrylate with N‐(5‐chloro‐2‐methoxyphenyl)itaconimide (OMCPI)/N‐(5‐chloro‐3‐methoxyphenyl)itaconimide (MCPI) monomers using AIBN as an initiator and THF as solvent at 60°C. Feed compositions having varying mole fractions of OMCPI and MCPI ranging from 0.1 to 0.5 were taken to prepare copolymers. Structural characterization of homopolymers and copolymers thus obtained was done using FT‐IR, 1H‐NMR, and elemental analysis. Copolymer composition was determined using percent nitrogen content. Comonomer reactivity ratios were determined using Kelen‐Tüdos and non‐linear error in variable model (EVM) method using RREVM computer program. Carbonyl carbon signals of MMA (M) as well as N‐aryl itaconimide (I) copolymers in the 13C{1H}‐NMR spectra were used for the determination of sequence distribution of M‐and I‐centered triads. Sequence distribution of M‐ and I‐ centered triads calculated using 13C{1H}‐NMR spectra are in good agreement with the theoretically calculated values using Harwood's model. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Microwave preparation and adsorption properties of EDTA‐modified cross‐linked chitosan
Authors: Ge Huacai , Huang Shiying
Published: September 2009

A novel chitosan‐based adsorbent (CCTE) was synthesized by the reaction between epichlorohydrin O‐cross‐linked chitosan and EDTA dianhydride under microwave irradiation (MW). The chemical structure of this new polymer was characterized by infrared spectra analysis, thermogravimetric analysis, and X‐ray diffraction analysis. The results were in agreement with the expectations. The static adsorption properties of the polymer for Pb2+, Cu2+, Cd2+, Ni2+, and Co2+ were investigated. Experimental results demonstrated that the CCTE had higher adsorption capacity for the same metal ion than the parent chitosan and cross‐linked chitosan. In particular, the adsorption capacities for Pb2+ and Cd2+ were 1.28 mmol/g and 1.29 mmol/g, respectively, in contrast to only 0.372 mmol/g for Pb2+ and 0.503 mmol/g for Cd2+ on chitosan. Kinetic experiments indicated that the adsorption of CCTE for the above metal ions achieved the equilibrium within 4 h. The desorption efficiencies of the metal ions on CCTE were over 93%. Therefore, CCTE is an effective adsorbent for the removal and recovery of heavy metal ions from industrial waste solutions. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Novel crosslinked starch microspheres as adsorbents of Cu2+
Authors: Miao Zongcheng , Li Zhongjin , Deng Deng , Wang Lei , Liu Yong
Published: September 2009

A novel adsorbent, a crosslinked starch microsphere (CSM), was prepared from soluble starch and N,N′‐methylenebisacrylamide. The microporous structure of the CSM was determined with scanning electron microscopy. The diameter distribution of the CSMs was quite uniform, and the average diameter of the microparticles was estimated to be 50 μm. Cu2+ was introduced into the CSM. The successful adsorption of Cu2+ in the CSM was confirmed with Fourier transform infrared spectroscopy. The crystal structure of the CSM was destroyed after the incorporation of Cu2+. This was proven with X‐ray diffraction. The thermal stability of the CSM was weakened with the introduction of Cu2+ during simultaneous thermal analysis. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Effect of the polymerization conditions on the swelling of a copolymer of AA/AMPS/BA via experimental design
Authors: Rosa Fátima , Bordado João , Casquilho Miguel
Published: September 2009

To study the effect of the polymerization conditions on swelling, a copolymer was synthesized from the monomers acrylamide (AA), 2‐acrylamido‐2‐methyl‐propanosulfonic acid (AMPS) andN,N‐methylenobisacrylamide (BA) as crosslinker by an inverse emulsion technique. The conditions were: concentration of organic solvent,s(an isoparaffinic hydrocarbon, commercially Isopar M), concentration of emulsifier,e(sorbitan trioleate, commercially Tween 85), and reaction temperature,T. These three variables (factors) were explored to achieve highest water absorbency, a 23factorial experimental design having been applied to find the main and two‐factor interaction effects of those variables on the swelling capacity. A predictive model including the factors for the swelling is proposed, allowing for the estimation of absorbency capacity in this type of copolymers. The results show that the optimum values of the variables given by the experimental design weres= 8.1,e= 1.0, andT= 49°C, with predicted swelling capacity of 1041 and experimental of 1014. The variables are relevant, with a preponderance ofs, and the effect of the square of temperature is also significant. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Synthesis and photovoltaic properties of polythiophene derivatives with side chains containing C60 end group
Authors: He Youjun , Hou Jianhui , Tan Zhan'ao , Li Yongfang
Published: September 2009

A donor–acceptor double‐cable polythiophene derivative (PT‐F1) with side chain containing C60 end group was synthesized, and characterized by infrared, UV‐vis absorption and photoluminescence (PL) spectroscopy, and electrochemical cyclic voltammetry. Cyclic voltammogram of PT‐F1 shows the oxidation peak of the polymer main chains and the reduction peaks of the C60 end groups, indicating that there is no interaction between the polymer main chains and side chain C60 groups on the ground state. The UV‐vis absorption spectrum of PT‐F1 film is red‐shifted in comparison with that of its chloroform solution. The PL spectrum of the polymer main chain was quenched by the C60 pendant on the side chain. Polymer solar cell with the structure of ITO/PEDOT:PSS/PT‐F1/Ca/Al was fabricated. The power conversion efficiency of the device based on PT‐F1 reached 0.274% under the illumination of AM 1.5, 100 mW/cm2. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Influence of oil contents in dynamically cured natural rubber and polypropylene blends
Authors: Nakason Charoen , Kaewsakul Wisut
Published: September 2009

Mechanical, dynamic, thermal, and morphological properties of dynamically cured 60/40 NR/PP TPVs with various loading levels of paraffinic oil were investigated. It was found that stiffness, hardness, tensile strength, storage shear modulus, complex viscosity, glass transition temperature (Tg) of the vulcanized rubber phase, degree of crystallinity and crystalline melting temperature (Tm) of the polypropylene (PP) phase decreased with increasing loading levels of oil. This is attributed to distribution of oil into the PP and vulcanized rubber domains causing oil‐swollen amorphous phase and vulcanized rubber domains. An increasing trend of elastic response in terms of tension set and damping factor was observed in the TPVs with loading levels of oil in a range of 0–20 phr. It is supposed that a major proportion of oil was first preferably migrated into the PP phase and caused an abrupt decreasing trend of degree of crystallinity and Tm of the PP phase. The dispersed vulcanized rubber domains remained small as particles with a low degree of swelling. Increasing loading levels of oil higher than 20 phr caused a decreasing trend of elongation at break and elastomeric properties. Saturation of oil in the PP phase was expected and the excess oil was transferred to the rubber phase which thereafter caused larger swollen vulcanized rubber domains. The remaining amount of oil was able to separate as submicron pools distributed in the PP matrix. This caused lowering of Tg, Tm, crystallinity of PP phase as well as strength, elastomeric, and dynamic properties of the TPVs. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Synthesis and characterization of butyl acrylate/methyl methacrylate/glycidyl methacrylate latexes
Authors: Mishra Sujata , Singh Jagbir , Choudhary Veena
Published: September 2009

The butyl acrylate (BA)/methyl methacrylate (MMA), and glycidyl methacrylate (GMA) composite copolymer latex was synthesized by seeded emulsion polymerization technique taking poly(methyl methacrylate) (PMMA) latex as the seed. Four series of experiments were carried out by varying the ratio of BA : MMA (w/w) (i.e. 3.1 : 1, 2.3 : 1, 1.8 : 1, and 1.5 : 1) and in each series GMA content was varied from 1 to 5% (w/w). The structural properties of the copolymer were analyzed by FTIR, 1H‐, and 13C‐NMR. Morphological characterization was carried out using transmission electron microscopy (TEM). In all the experiments, monomer conversion was ∼99% and final copolymer composition was similar to that of feed composition. The incorporation of GMA into the copolymer chain was confirmed by 13C‐NMR. The glass transition temperature (Tg) of the copolymer latex obtained from the differential scanning calorimetry (DSC) curve was comparable to the values calculated theoretically. With increase in GMA content, particles having core‐shell morphology were obtained, and there was a decrease in the particle size as we go from 2–5% (w/w) of GMA. The adhesive strength of the latexes was found to be dependent on the monomer composition. With increase in BA : MMA ratio, the tackiness of the film increased while with its decrease the hardness of the film increased. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Reduction of volatile organic compound emission. II. Use of alkoxy‐modified silsesquioxane for compounding silica‐filled rubbers
Authors: Lin Chenchy J. , Hergenrother William L. , Hilton Ashley S.
Published: September 2009

A class of alkoxy‐modified silsesquioxane (AMS) containing less than 5 wt % of latent alcohol that can be used for compounding silica‐filled rubbers is described. The AMS derived from octyl‐triethoxysilane (OTES) behaves as a good shielding agent in silica‐filled rubber to significantly reduce the compound Mooney viscosity and filler flocculation. The co‐AMS prepared from OTES and 3‐mercaptopropyl‐trimethoxysilane yielded an effective shielding and coupling agent for reinforcing the silica‐filled vulcanizates. The alcohols released as volatile organic compounds (VOC) are quantified during compounding and processing along with the compound properties of silica‐filled vulcanizates containing various silicon compounds such as bis‐(triethoxysilyl propyl) disulfide (TESPD), a polyhedral oligomeric silsesquioxanes (POSS), OTES, AMS, or co‐AMS. Dynamic mechanical properties such as dependences of hysteresis on temperature (HTD) and storage modulus on strain (MSD) are discussed. Stronger HTD and weaker MSD were found in stocks containing co‐AMS or a combination of AMS and a coupling agent when compared with that with TESPD. Stronger HTD and weaker MSD may benefit a tire compound with lower rolling resistance, more stable handling performance, as well as better wet traction. More importantly, the VOC released during the manufacture of rubber articles are significantly reduced in stocks containing AMS (or co‐AMS) when compared with those with a silane. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Effect of modifiers on morphology and thermal properties of novel thermoplastic polyurethane‐peptized laponite nanocomposite
Authors: Mishra Ananta K. , Chattopadhyay Santanu , Nando Golok B.
Published: September 2009

Laponite RDS (Laponite containing pyrophosphate based peptizer) was modified with cetyl trimethyl ammonium bromide (cLS) and dodecylamine hydrochloride (dLS), respectively. Thermoplastic polyurethane (TPU)‐modified Laponite RDS nanocomposites were prepared by solution mixing technique. Morphologies of these two modified clay‐nanocomposites are found to be markedly different. cLS based TPU nanocomposites exhibit partly exfoliated, intercalated, and aggregated structure at lower clay content but a network type of structure is observed at higher clay content. However, dLS based TPU nanocomposites demonstrate spherical cluster type of structure at all clay contents. Nearly two fold increase in storage modulus is observed in both glassy and rubbery state with merely 1% cLS content which gradually decreases with an increase in the clay content. However, in case of dLS filled nanocomposite, gradual increase in storage modulus is observed with an increase in the clay content. Thermogravimetric analysis (TGA) studies indicate that the temperature corresponding to 5 wt % degradation of TPU is enhanced by 19.1 and 12.5°C with the addition of merely 1% cLS and dLS, respectively. However, the activation energy of degradation of neat TPU, as determined by isothermal TGA analysis, is found to be higher than that of the nanocomposites containing 1% of cLS and dLS, respectively. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Ethyl vinyl acetate copolymer—SrAl2O4:Eu,Dy and Sr4Al14O25:Eu,Dy phosphor‐based composites: Preparation and material properties
Authors: Mishra S. B , Mishra A. K. , Luyt A. S. , Revaprasadu N. , Hillie K. T. , vdM Steyn W. J. , Coetsee E. , Swart H. C.
Published: September 2009

New photoactive composite based on ethyl vinyl acetate (EVA) and SrAl2O4:Eu,Dy or Sr4Al14O25:Eu,Dy were prepared by melt mixing or extrusion methodologies. The phosphorescent behavior and material properties of the polymer‐phosphor composites were studied. The morphology of the polymer and the composites were studied by using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive X‐ray spectroscopy (EDS). The SEM shows that the physical and chemical behavior of the matrix and the extrusion conditions were primarily responsible for the surface morphology. TEM and EDS show that the phosphor particles were uniformly dispersed in the EVA matrix. A broad band of ultraviolet (UV)‐excited phosphorescence of SrAl2O4:Eu,Dy and Sr4Al14O25:Eu,Dy phosphors and the respective composites were observed at wavelengths of 516 nm and 490 nm, respectively. The photoluminescence (PL) spectra showed less intense phosphorescence but no shift in the wavelength of the emission peak for all the composites. The Hamburg wheel test was done on all the composites and the PL measurements before and after the test showed almost no change in the intensity of the emission. Thermal studies showed that the presence of the phosphors in the matrix slightly increased the crystallinity of EVA, which leads to higher melting enthalpies. Tensile testing shows very little change in the tensile strength and flexibility of the ethylene vinyl acetate copolymer. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Toughened nylon66/nylon6 ternary nanocomposites by elastomers
Authors: Chen Jun , Wu Wei , Chen Chuan , He Sanxiong
Published: September 2009

The elastomer toughening of PA66/PA6 nanocomposites prepared from the organic modified montmorillonite (OMMT) was examined as a means of balancing stiffness/strength versus toughness/ductility. Several different formulations varying in OMMT content were made by mixing of PA6 and OMMT as a master‐batch and then blending it with PA66 and different elastomers in a twin screw extruder. In this sequence, the OMMT layers were well exfoliated in the nylon alloy matrix. The introduction of silicate layers with PA6 induced the appearance of the γ crystal phase in the nanocomposites, which is unstable and seldom appears in PA66 at room temperature and it further affected the morphology and dispersion of rubber phase resulting in much smaller rubber particles. The incorporation of POE‐g‐MA particles toughened the nanocomposites markedly, but the tensile modulus and strength were both reduced. Conversely, the use of OMMT increased the modulus but decreased the fracture toughness. The nanocomposites exhibited balanced stiffness and toughness. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
The copper sulfide coating on polyacrylonitrile with a chelating agent of ethylenediaminetetraacetic acid by an electroless deposition method and its EMI shielding effectiveness
Authors: Chen Yen‐Hung , Huang Chi‐Yuan , Roan Ming‐Lih , Lai Fu‐Der , Chen Kan‐Nan , Yeh Jen‐Taut
Published: September 2009

In this study, a copper sulfide layer was instantaneously coated on the polyacrylonitrile (PAN) by an electroless plating method with the reduction agents NaHSO3 and Na2S2O3·5H2O and a chelating agent (ethylenediaminetetraacetic acid, EDTA). A variety of concentrations of EDTA was added to obtain the anchoring effect and chelating effect in the electroless plating bath. The mechanism of the Cux(x = 1, 2)S growth and the electromagnetic interference shielding effectiveness (EMI SE) of the composite were studied. It was found that the vinyl acetate was residual in PAN substrate would be purged due to the swelling effect by EDTA solution. Then, the anchoring effect occurred due to the hydrogen bonding between the pits of PAN substrate and the chelating agent. Consequently, the copper sulfide layer deposited successfully by the electroless plating reacted upon EDTA. The swelling degree (Sd) was proposed and evaluated from the FTIR spectra. The relationship between swelling degree of the PAN composite and EDTA concentration (C) is expressed as follows: Sd = 0.13 + 0.90 × e(−15.15C). On the other hand, the FESEM micrograph showed that the average thickness of copper sulfide increased from 76 to 383 nm when the concentration of EDTA increased from 0.00 to 0.20M. For this reason, the EMI SE of the composites increased from 10–12 dB to 20–23 dB. The GIA‐XRD and laser Raman analysis indicated that the deposited layer consisted of CuS and Cu2S. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Effect of hot drawing on properties of wet‐spun poly(L,D‐lactide) copolymer multifilament fibers
Authors: Rissanen Marja , Puolakka Arja , Hukka Terttu , Ellä Ville , Kellomäki Minna , Nousiainen Pertti
Published: September 2009

Polylactide stereocopolymer multifilament fibers were prepared by wet spinning and subsequent hot drawing. The stereocopolymers were poly‐(L,D‐lactide) [P(L,D)LA], L/D ratio 96/4, and poly‐(L,DL‐lactide) [P(L,DL)LA], L/DL ratio 70/30. They were dissolved in dichloromethane and coagulated in a spin bath containing ethanol. The hot‐drawing temperature was 65°C. The draw ratios (DR) were upto 4.5 to the P(L,D)LA 96/4 filaments and upto 3 to the P(L,DL)LA 70/30 filaments. Wet spinning decreased crystallinities of both copolymers. Hot drawing increased the crystallinity of the P(L,D)LA 96/4 filament but not to the level of the original copolymer, whereas the as‐spun and the hot‐drawn P(L,DL)LA 70/30 filaments were amorphous. The filament diameter, tenacity, Young's modulus, and elongation at break were dependent on the DR. The maximum tenacity (285 MPa) and Young's modulus (2.0 GPa) were achieved with the P(L,D)LA 96/4 filament at the DR of 4.5. Respectively, the maximum tenacity of the hot‐drawn P(L,DL)LA 70/30 filament was 175 MPa and Young's modulus 1.3 GPa at the DR of 3. Hot drawing slowed down in vitro degradation rate of both stereocopolymer filaments. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
In vitro release kinetics of bovine serum albumin from highly swellable dextran hydrogels
Authors: İmren Dilek , Gümüşderelioğlu Menemşe , Güner Ali
Published: September 2009

Hydrogels synthesized from a polysaccharide‐based polymer, dextran, in the presence of two crosslinking agents, N,N′‐methylenebisacrylamide and epichlorohydrin, were evaluated for the oral colon‐specific delivery of polypeptide drugs. These novel dextran hydrogels had significantly greater swelling ratios than recently developed dextran hydrogels. A model protein, bovine serum albumin, was loaded into 50% (by weight) crosslinker‐containing dextran hydrogels in two ways: during the crosslinking reaction and by a soaking method. The loading capacity was varied between 22 and 25 mg/g of dry gel, depending on the loading procedure. In vitro release experiments were performed with a simulated gastrointestinal system in the presence and absence of dextranase. The diffusion exponents were calculated by means of a semiempirical power‐law equation for the release of protein from swellable hydrogel discs. Bovine serum albumin was mainly released by Fickian diffusion, and this indicated that its hydrodynamic diameter (7.7 nm) was smaller than the hydrogel mesh size (∼19 nm). The release of bovine serum albumin from both hydrogel types was substantially higher than expected, especially in the presence of dextranase, and this was attributed to the high swellability of the hydrogels. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Crossflow filtration of iron(III), copper(II), and cadmium(II) aqueous solutions with alginic acid/cellulose composite membranes
Authors: Çifci Cemal , Şanlı Oya
Published: September 2009

The removal of Fe(III), Cu(II), and Cd(II) ions from aqueous solutions was investigated with a crossflow filtration technique. Alginic acid (AA)/cellulose composite membranes were used for retention. In the filtration of Fe(III) solutions, the effects of the crossflow velocity, applied pressure, AA content of the membranes, and pH on the retention percentage and the permeate flux were examined. The maximum retention percentage was found to be 89% for a 1 × 10−4M Fe(III) solution at the flow velocity of 100 mL/min and the pressure of 60 kPa with 0.50% (w/v) AA/cellulose composite membranes at pH 3. Aqueous solutions of Cu(II) and Cd(II) were filtered at the flow velocity of 100 mL/min and pressure of 10 kPa. The effects of the AA content of the membranes and pH of the waste medium on the retention percentage and the permeate flux were determined. For 1 × 10−4M Cu(II) and Cd(II) solutions, the maximum retention percentages were found to be 94 and 75%, respectively, at pH 7 with 0.50% (w/v) AA/cellulose composite membranes. When metal‐ion mixtures were used, the retention percentages of Fe(III), Cu(II), and Cd(II) were found to be 89, 48, and 10%, respectively, at pH 3 with 0.50% (w/v) AA/cellulose composite membranes. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Ferulic acid as a comonomer in the synthesis of a novel polymeric chain with biological properties
Authors: Iemma Francesca , Puoci Francesco , Curcio Manuela , Parisi Ortensia I. , Cirillo Giuseppe , Spizzirri Umile G. , Picci Nevio
Published: September 2009

In this study, ferulic acid was copolymerized with methacrylic acid to obtain a useful material with both antioxidant and antifungal properties. An ascorbic acid/hydrogen peroxide redox pair was used as a water‐soluble and biocompatible initiator system to prime the one‐pot polymerization reaction. The obtained material was characterized with gel permeation chromatography, Fourier transform infrared spectroscopy, ultraviolet spectroscopy, and fluorescence analyses, and the disposable phenolic group content was determined to verify the insertion of ferulic acid into the polymeric backbone. Finally, the antioxidant and antifungal activities were demonstrated toward the hydroxyl radical and Aspergillus niger, respectively. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Enantioselective Protonation of Itaconimides with Thiols and the Rotational Kinetics of the Axially Chiral CN Bond
Authors: Lin Shishi , Leow Dasheng , Huang Kuo‐Wei , Tan Choon‐Hong
Published: September 2009

Bicyclic guanidines are able to catalyze the protonation reactions of 2‐phthalimidoacrylates with thiols in excellent yields and enantioselectivities. The protonation reaction of itaconimides with secondary phosphine oxides is also known. Herein, the tandem conjugate addition–enantioselective protonation ofN‐substituted itaconimides with thiols catalyzed by chiral bicyclic guanidine is investigated. The rotational barrier of the CN axis ofN‐2‐tert‐butyl phenylitaconimide is also studied, both experimentally and computationally.
Comparative gene expression of intestinal metabolizing enzymes
Authors: Shin Ho‐Chul , Kim Hye‐Ryoung , Cho Hee‐Jung , Yi Hee , Cho Soo‐Min , Lee Dong‐Goo , Abd El‐Aty A. M. , Kim Jin‐Suk , Sun Duxin , Amidon Gordon L.
Published: September 2009

The purpose of this study was to compare the expression profiles of drug‐metabolizing enzymes in the intestine of mouse, rat and human. Total RNA was isolated from the duodenum and the mRNA expression was measured using Affymetrix GeneChip oligonucleotide arrays. Detected genes from the intestine of mouse, rat and human were ca. 60% of 22690 sequences, 40% of 8739 and 47% of 12559, respectively. Total genes of metabolizing enzymes subjected in this study were 95, 33 and 68 genes in mouse, rat and human, respectively. Of phase I enzymes, the mouse exhibited abundant gene expressions for Cyp3a25, Cyp4v3, Cyp2d26, followed by Cyp2b20, Cyp2c65 and Cyp4f14, whereas, the rat showed higher expression profiles of Cyp3a9, Cyp2b19, Cyp4f1, Cyp17a1, Cyp2d18, Cyp27a1 and Cyp4f6. However, the highly expressed P450 enzymes were CYP3A4, CYP3A5, CYP4F3, CYP2C18, CYP2C9, CYP2D6, CYP3A7, CYP11B1 and CYP2B6 in the human. For phase II enzymes, glucuronosyltransferase Ugt1a6, glutathione S‐transferases Gstp1, Gstm3 and Gsta2, sulfotransferase Sult1b1 and acyltransferase Dgat1 were highly expressed in the mouse. The rat revealed predominant expression of glucuronosyltransferases Ugt1a1 and Ugt1a7, sulfotransferase Sult1b1, acetyltransferase Dlat and acyltransferase Dgat1. On the other hand, in human, glucuronosyltransferases UGT2B15 and UGT2B17, glutathione S‐transferases MGST3, GSTP1, GSTA2 and GSTM4, sulfotransferases ST1A3 and SULT1A2, acetyltransferases SAT1 and CRAT, and acyltransferase AGPAT2 were dominantly detected. Therefore, current data indicated substantial interspecies differences in the pattern of intestinal gene expression both for P450 enzymes and phase II drug‐metabolizing enzymes. This genomic database is expected to improve our understanding of interspecies variations in estimating intestinal prehepatic clearance of oral drugs. Copyright © 2009 John Wiley & Sons, Ltd.
Arsenate‐induced apoptosis in murine embryonic maxillary mesenchymal cells via mitochondrial‐mediated oxidative injury
Authors: Singh Saurabh , Greene Robert M. , Pisano M. Michele
Published: September 2009

BACKGROUND: Arsenic is a ubiquitous element that is a potential carcinogen and teratogen and can cause adverse developmental outcomes. Arsenic exerts its toxic effects through the generation of reactive oxygen species (ROS) that include hydrogen peroxide (H2O2), superoxide‐derived hydroxyl ion, and peroxyl radicals. However, the molecular mechanisms by which arsenic induces cytotoxicity in murine embryonic maxillary mesenchymal (MEMM) cells are undefined. METHODS: MEMM cells in culture were treated with different concentrations of pentavalent sodium arsenate [As (V)] for 24 or 48 hr and various end points measured. RESULTS: Treatment of MEMM cells with the pentavalent form of inorganic arsenic resulted in caspase‐mediated apoptosis, accompanied by generation of ROS and disruption of mitochondrial membrane potential. Treatment with caspase inhibitors markedly blocked apoptosis. In addition, the free radical scavenger N‐acetylcysteine dramatically attenuated arsenic‐mediated ROS production and apoptosis, and exposure to arsenate increased Bax and decreased Bcl protein levels in MEMM cells. CONCLUSIONS: Taken together, these findings suggest that in MEMM cells arsenate‐mediated oxidative injury acts as an early and upstream initiator of the cell death cascade, triggering cytotoxicity, mitochondrial dysfunction, altered Bcl/Bax protein ratios, and activation of caspase‐9. Birth Defects Research (Part A), 2010. © 2009 Wiley‐Liss, Inc.
Flow injection chemiluminescence determination of 6‐mercaptopurine based on a new system of potassium permanganate–thioacetamide–sodium hexametaphosphate
Authors: Wang Lun , Ling Bo , Chen Hongqi , Liang Ani , Qian Binbin , Fu Jie
Published: September 2009

A novel chemiluminescence method for the determination of 6‐mercaptopurine was established based on 6‐mercaptopurine inhibition of the chemiluminescence emission of potassium permanganate–thioacetamide–sodium hexametaphosphate system. The peak height was proportional to log 6‐mercaptopurine concentration in the range 7.0 × 10−10 to 1.0 × 10−7 g/mL and the detection limit was 1.9 × 10−11 g/mL (S/N = 3). The relative standard deviation was 1.5% for the determination of 8.0 × 10−8 g/mL 6‐mercaptopurine (n = 11). The proposed sensor was successfully applied to the analysis of 6‐mercaptopurine in human serum samples. Copyright © 2009 John Wiley & Sons, Ltd.
A DIGE approach for the assessment of differential expression of the CHO proteome under sodium butyrate addition: Effect of Bcl‐xL overexpression
Authors: Baik Jong Youn , Lee Gyun Min
Published: September 2009

Bcl‐xL, a member of the Bcl‐2 family, is known to inhibit apoptosis of recombinant Chinese hamster ovary (rCHO) cells induced by the addition of sodium butyrate (NaBu), which is used for the elevated expression of recombinant protein. In order to understand the intracellular effects of Bcl‐xL overexpression on CHO cells treated with NaBu, changes to the proteome caused by controlled Bcl‐xL expression in rCHO cells producing erythropoietin (EPO) in the presence of 3 mM NaBu were evaluated using two‐dimensional differential in‐gel electrophoresis (2D‐DIGE) and MS analysis. The consequences of Bcl‐xL overexpression were not limited to the apoptotic signaling pathway. Out of eight proteins regulated significantly by Bcl‐xL overexpression in 3 mM NaBu addition culture, four proteins were related to cell survival (Iq motif‐containing GTPase‐activating protein 1), cell proliferation (dihydrolipoamide‐S‐acetyltransferase, guanine nucleotide binding protein alpha interacting 2), and repair of DNA damage (BRCA and CDKN1A interacting protein). Taken together, a DIGE approach reveals that overexpression of Bcl‐xL not only inhibits apoptosis in the presence of NaBu but also affects cell proliferation and survival in various aspects. Biotechnol. Bioeng. 2010; 105: 358–367. © 2009 Wiley Periodicals, Inc.
Rapid production of recombinant human IgG With improved ADCC effector function in a transient expression system
Authors: van Berkel Patrick H.C. , Gerritsen Jolanda , van Voskuilen Edwin , Perdok Gerrard , Vink Tom , van de Winkel Jan G.J. , Parren Paul W.H.I.
Published: September 2009

Rapid production of recombinant human IgG with improved antibody dependent cell‐mediated cytotoxicity (ADCC) effector function is presented. The technique employs transient expression of IgG in suspension growing HEK‐293F cells in the presence of the glycosidase inhibitor kifunensine. The procedure takes ∼7 days, provided that expression plasmids encoding the IgG of interest are available. Kifunensine inhibits the N‐linked glycosylation pathway of HEK‐293F cells in the endoplasmatic reticulum, resulting in IgG with oligomannose type glycans lacking core‐fucose. IgG1 transiently produced in kifunensine‐ treated HEK‐293F cells has improved affinity for the FcγRIIIA molecule as measured in an ELISA based assay, and almost eightfold enhanced ADCC using primary peripheral blood mononuclear effector cells. Biotechnol. Bioeng. 2010; 105: 350–357. © 2009 Wiley Periodicals, Inc.
Pathways to psychiatric care in European prison systems
Authors: Dressing Harald , Salize Hans‐Joachim
Published: September 2009

The aims of this study were to describe and analyse the concepts of provision of mental health services for prison inmates in 24 countries in the European Union and the EFTA. Data were gathered by means of a structured questionnaire that was completed by national experts in the participating countries. This article stresses the different organizational models of mental health care for inmates, different legal standards for screening their mental health status and different pathways to psychiatric care and aftercare. The study revealed serious shortcomings. Even the most rudimentary health reporting standards for mental health care in prison are lacking almost everywhere in Europe. Psychiatric screening and assessment procedures at prison entry and during imprisonment differ substantially and do not fulfil recognized quality standards. In many countries, the appointment of inadequately trained staff to perform such screenings increases considerably the risk that mental disorders or psychiatric needs of the inmates will remain undetected. Furthermore, the pathways to care in the case of an acute psychotic episode differ significantly, since referral to prison hospitals, medical prison wards, forensic hospitals, or general psychiatric hospital are used in various combinations depending on different national legal regulations and on the availability of services or other regional circumstances. Therefore, the collaborating experts place the quality of European prison mental health care into serious question. Copyright © 2009 John Wiley & Sons, Ltd.