bluuebunny/crossref_metadata_2025 huggingface dataset:
Nonrigid microporous PVC sheets: Preparation and properties
Authors: Trommer Kristin , Morgenstern Bernd
Published: October 2009

The non‐rigid microporous PVC films are prepared by mono‐axially stretching nonporous sheets containing fillers which show an average particle size of 2 to 10 μm. The nonporous PVC film is generated from paste‐like PVC. The influence of recipe components on the mechanical properties, morphological behavior and permeability to water vapor and water was investigated as well as the influence of the stretching ratio. Filled PVC pastes exhibit higher values for viscosity than those of pure polymer mixtures. For processing the compounded paste by means of a doctor blade a low viscosity is required meaning the amount of filler is limited by the resulting paste viscosity. Due to dewetting, the filler initiates the holes of the microporous system during the stretching process. Empirically, a minimum of about 15 vol % filler particles are necessary in order to achieve an interconnected air hole system. Varying the components PVC, plasticiser and filler, PVC membranes could be prepared with high water vapour permeability and high waterproofness simultaneously. To utilize the membranes commercially a continuous preparation process was developed. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Utilization of plant ash for the fabrication of novel superabsorbent composites with potassium‐release characteristics
Authors: Wang Wenbo , Wang Aiqin
Published: October 2009

Design and synthesis of the agricultural and ecological superabsorbent materials with cost‐efficient and fertilizer‐release characteristics has recently attracted considerable interests. In this work, the novel poly(sodium‐potassium acrylate‐co‐acrylamide)/plant ash (PNa‐KA‐co‐AM/PA) superabsorbent composites with potassium‐release characteristics were prepared using partially neutralized acrylic acid (Na‐KA), acrylamide (AM), and plant ash (PA) as raw materials, ammonium persulfate (APS) as the initiator, and N,N′‐methylenebisacrylamide (MBA) as the crosslinker. The structure, morphologies, and thermal stability of the composites were characterized by Fourier transform infrared spectrophotometer, scanning electron microscopy, and TGA techniques, respectively. The effects of MBA concentration and PA content on water absorbency were studied, and the swelling properties of the composites in saline solutions and various pHs solution as well as their potassium‐release capabilities were also evaluated. Results indicate that the composites exhibit better thermal stability, salt‐resistant performance, pH‐stability, and potassium‐release properties, and can act as a fertilizer and an effective water‐saving material for agricultural and ecological application. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Photografting of methacrylic acid onto hydroxyapatite particles surfaces
Authors: Gao Jun , Huang Bin , Lei Jingxin , Zheng Zhiming
Published: October 2009

The unsaturated functional groups (CC) were introduced onto hydroxypatite (HAP) particles surfaces by esterification reaction between hydroxyl groups on the HAP surface and methacrylic acid (MAA). Then, graft polymerization of MAA onto the esterified HAP particles surfaces was carried out by ultraviolet light (UV) initiation. The structure of the surface‐esterified and grafted HAP was studied by ESCA, FTIR, Scanning Electron microscopy, laser particle sizes analyze, esterification, and graft degrees tests. The results show that poly(methyl acrylic acid) (PMAA) is successfully inserted onto HAP particles surfaces by covalent bond linkage. The esterification degree between MAA and HAP particles increases with reaction temperature and time, and tends to level off at about 6 h under 90°C. The graft degree of MAA onto HAP particles with 1.14% esterification degree and its average particle sizes increase with UV initiation polymerization time, and to reach a maximum at 25 min under 40°C, then decrease as irradiation time further increases. The surfaces of the grafted HAP particles become rough and loose. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Poly(ethylene terephthalate‐co‐isophthalate) copolyesters obtained from ethylene terephthalate and isophthalate oligomers
Authors: Ubach Joan , de Ilarduya Antxon Martínez , Quintana Robert , Alla Abdelilah , Rudé Elisabet , Muñoz‐Guerra Sebastián
Published: October 2009

A series of poly(ethylene terephthalate‐co‐isophthalate) copolyesters containing upto 50%‐mole of isophthalic units were prepared by polycondensation from ethylene terephthalate and ethylene isophthalate fractions of linear oligomers containing from 5 to 6 repeating units in average. The polyesters were obtained in good yields and with high‐molecular‐weights. The microstructure of the copolyesters was studied as a function of reaction time by 13C‐NMR showing that a random distribution of the comonomers was achieved since the earlier stages of polycondensation. The melting temperature and enthalpy of the copolyesters decreased with the content of isophthalic units so that copolyesters containing more than 25% of these units were amorphous. Isothermal crystallization studies made on crystalline copolyesters revealed that the crystallization rate of copolyesters decreased with the content in isophthalic units. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Microstructural parameters in electron‐irradiated C108 silk fibers by wide‐angle X‐ray scattering studies
Authors: Sangappa  , Asha S. , Sanjeev Ganesh , Subramanya G. , Parameswara P. , Somashekar R.
Published: October 2009

The present study looks into the microstructural changes in C108 (Bombyx mori) silk fibers, induced by electron irradiation. The irradiation process was performed in air at room temperature by the use of 8 MeV electron accelerators at different doses: 0, 25, 50, 75, and 100 kGy, respectively. The changes in microstructural parameters in these natural polymer fibers have been studied using wide‐angle X‐ray scattering method. The crystal imperfection parameters such as crystallite size 〈N〉, lattice strain (g in %), and enthalpy (α*) have been determined by line profile analysis using Fourier method of Warren. Exponential, lognormal, and Reinhold functions for the column length distributions have been used for the determination of these parameters. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Effects of dilution with PMMA and network formation on fluorescence from benzimidazolylphenylenes linked to PMMA network
Authors: Wongjuntaramanee Kunapong , Tsuchiya Masahiro , Ishimaru Kaori , Kojima Takakazu
Published: October 2009

N,N′‐5‐(2‐benzimidazolyl)‐1,3‐phenylenebis(methacrylamide) (BIPBMA) was synthesized and copolymerized with methyl methacrylate (MMA) by changing feed BIPBMA/MMA molar ratio. The swelling experiments suggest that these cross‐linked copolymers (c‐copolymers) have a polymer network structure. To compare with c‐copolymers, synthesized 3‐(2‐benzimidazolyl) phenylmethacrylamide (BIPMA) was copolymerized with MMA by changing feed BIPMA/MMA molar ratio. These linear copolymers (l‐copolymers) were dissolved in N,N‐dimethylacetamide (DMA). The fluorescence spectra of c‐copolymers were well fitted by trial‐and‐error contraction with sums of five or less of Lorentzian equations. The fluorescence spectra of l‐copolymers were so distributed that only the initial peak was fitted to a single Lorentzian equation. The fluorescence spectra of BIPBMA/DMA solutions with various concentrations were also fitted to sums of five or less of Lorentzian equations. The fitted coefficients were used to quantify dilution effect. The fluorescence intensity of c‐copolymers is higher than that of l‐copolymers in a same chromophore concentration. A relation between the intensity and the chromophore concentration shows a concentration quenching owing to chromophore aggregating for c‐copolymer, l‐copolymer, and the solution. A critical concentration point before which the intensity increases appeared in the plots of intensity against concentration for the c‐copolymer and the solution. The critical point of the c‐copolymer is higher than that of the solution and that of the l‐copolymer (if observed). This suggests that the network formation and the dilution break up the chromophore aggregates. The fluorescence spectra of c‐copolymers (1/200) adjusted by varying AIBN concentrations suggest that the fluorescence is independent of the extent of cross‐linking. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Studies on water absorption of bamboo‐epoxy composites: Effect of silane treatment of mercerized bamboo
Authors: Kushwaha Pradeep K. , Kumar Rakesh
Published: October 2009

The effect of silane treatment on the water absorption properties of bamboo matting reinforced epoxy composites were investigated. Experiments using γ‐aminopropyltriethoxy silane, 3‐trimethoxysilylpropylmethacrylate, vinyltris(2‐methoxyethoxy)silane, bis[3‐(triethoxysilyl)propyl]tetrasulfide, 3‐aminopropyltrimethoxysilane, and n‐octyltrimethoxysilane were carried out to improve the water resistant property of the bamboo fiber composites. Water absorption in the composites was studied by long term immersion and 2 h boiling in distilled water. The process of absorption of water was found to follow the kinetics and mechanism described by Fick's theory. Alkali treatment results in reduction of water absorption from 41 to 26%. Further reduction is observed with silane treatment. Water absorption varies between 21 and 24%, minimum being for aminopropyltriethoxysilane treated composite. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Thermal degradation of high‐temperature fluorinated polyimide and its carbon fiber composite
Authors: Adamczak Andrea D. , Spriggs Adam A. , Fitch Danielle M. , Awad Walid , Wilkie Charles A. , Grunlan Jaime C.
Published: October 2009

High‐temperature polymers are being used for a broad range of applications, such as composite matrices for structural applications (e.g., high speed aircraft). Polyimides are a special class of polymers that meet the thermal and oxidative stability requirements for high temperature composite aerospace applications. A weight loss study was performed on a fluorinated polyimide resin and its carbon fiber composite in an effort to determine its thermal stability and degradation mechanisms. Experiments were conducted using a preheated oven and thermogravimetric analysis to obtain the weight loss. Regardless of the method used, the resin and composite exhibited excellent thermal stability (less than 1% weight loss) below 430°C, regardless of 2–20 min of exposure. After 20 min of exposure at 510°C, the composite remained relatively stable with only 5.3% weight loss using the oven technique, whereas the neat polyimide sustained 12.6%. When degradation occurred, it was found to be the result of thermolysis and oxidation (to a lesser extent). © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Poly(lactic acid) and zeolite composites prepared by melt processing: Morphological and physical–mechanical properties
Authors: Yuzay Isinay E. , Auras Rafael , Selke Susan
Published: October 2009

Poly(lactic acid), PLA, composites containing 0, 1, 3, and 5 wt % zeolite type 4A were prepared using extrusion/injection compounding techniques. Morphological characterizations were carried out by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Physical properties were evaluated by differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) and mechanical properties by standard tensile testing. The morphological studies showed a homogenous dispersion of zeolite particles within the PLA matrix. As the fracture stress propagated, zeolite particles remained embedded into the matrix, indicating the existence of good interfacial adhesion between zeolite particles and the PLA matrix. The improvement in the interfacial adhesion was also confirmed by applying Nicolais‐Narkis and Pukanszky models. The percent crystallinity of the PLA and the temperature‐ dependant elastic and viscous modulus of the composite increased with the proportion of zeolites. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Effects of mixed solvents and PVDF types on performances of PVDF microporous membranes
Authors: Li Qian , Xu Zhen‐Liang , Yu Li‐Yun
Published: October 2009

Polyvinylidene fluoride (PVDF) microporous flat membranes were cast with different kinds of PVDFs and four mixed solvents [trimethyl phosphate (TMP)–N,N‐dimethylacetamide (DMAc), triethyl phosphate (TEP)–DMAc, tricresyl phosphate (TCP)–DMAc, and tri‐n‐butyl phosphate (TBP)–DMAc]. The effects of different commercial PVDFs (Solef® 1015, FR 904, Kynar 761, Kynar 741, Kynar 2801) on membrane morphologies and membrane performances of PVDF/TEP–DMAc/PEG200 system were investigated. The membrane morphologies were examined by scanning electron microscopy (SEM). The membrane performances in terms of pure water flux, rejection, porosity, and mean pore radius were measured. The membrane had the high flux of 143.0 ± 0.9 L m−2 h−1 when the content of TMP in the TMP–DMAc mixed solvent reached 60 wt %, which was 2.89 times that of the membrane cast with DMAc as single solvent and was 3.36 times that of the membrane cast with TMP as single solvent. Using mixed solvent with different solvent solubility parameters, different morphologies of PVDF microporous membranes were obtained. TMP–DMAc mixed solvent and TEP–DMAc mixed solvent indicated the stronger solvent power to PVDF due to the lower solubility parameter difference of 1.45 MPa1/2 and the prepared membranes showed the faster precipitation rate and the higher flux. The less macrovoids of the membrane prepared with TEP (60 wt %)–DMAc (40 wt %) as mixed solvent contributed to the higher elongation ratio of 96.61% ± 0.41%. Therefore, using TEP(60 wt %)–DMAc (40 wt %) as mixed solvent, the casting solution had the better solvent power to PVDF, and the membrane possessed the excellent mechanical property. The microporous membranes prepared from casting solutions with different commercial PVDFs exhibited similar morphology, but the water flux increased with the increment of polymer solution viscosity. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Epoxy acrylate UV/PU dual‐cured wood coatings
Authors: Chang Chia‐Wei , Lu Kun‐Tsung
Published: October 2009

For improving the finishing performances of complicated three‐dimensional coated wood products (e.g., furniture) with some shadow zones in the absence of ultraviolet (UV) light, resulting in incomplete curing of UV coatings, the aim of this study was to investigate the characteristics and effects of curing process on the properties of epoxy acrylate UV/PU dual‐cured resin for wood coatings when compared with traditional UV and polyurethane (PU) coatings. The epoxy acrylate oligomer was synthesized for providing a double bond of acryloyl group and a secondary hydroxyl group. The UV/PU dual‐cured coating was formulated with epoxy acrylate resin/tripropylene glycol diacrylate (TPGDA) monomer by the weight ratio of 80/20, 3% dosage of benzil dimethyl ketal as a photoinitiator, and the NCO/OH mole ratio of 1.0. The aromatic polymeric diphenylmethane diisocyanate was used as a hardener. The films of the dual‐cured coating, obtained from UV‐cured or room temperature‐cured process, showed an excellent tensile strength, elongation at break, impact resistance, and lightfastness when compared with traditional UV and PU coatings; especially, the adhesion of UV/PU dual‐cured coating by UV‐cured process was better than that of traditional UV coating. It can therefore be concluded that the epoxy acrylate oligomer‐based dual‐cured coating could readily be used for complicated wood products finishing. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Optimal preparation and characterization of poly(urea–formaldehyde) microcapsules
Authors: Ting Zhang , Min Zhang , Xiao‐Mei Tong , Feng Chen , Jian‐Hui Qiu
Published: October 2009

Microcapsules with epoxy curing agent were successfully prepared by an in‐situ polymerization route with epoxy resin and poly‐(urea–formaldehyde) as core and shell materials, respectively. The synthetic conditions were optimized by a comprehensive investigation on raw materials consumption, size distribution, and surface morphology. Preparation of microcapsules with high wrap ratio was also demonstrated. The as‐synthesized microcapsules were studied using various characterizations techniques, including optical microscope, fourier transform infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry, and contact angle meter. Spherical microcapsules (size: ∼ 60 μm) with smooth surface were obtained when the stirring rate was 400 rpm and the amount of core materials is 76 wt %. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Optical properties of particle‐filled polycarbonate, polystyrene, and poly(methyl methacrylate) composites
Authors: Zhou Rui‐Juan , Burkhart Thomas
Published: October 2009

Transparency is a key material property of polycarbonate (PC), polystyrene (PS), and poly(methyl methacrylate) (PMMA). To study the optical properties of particle‐filled PC, PS, and PMMA, composites containing inorganic particles in different sizes and concentrations were produced by direct melt mixing in this work. The optical properties characterized by total light transmittance, haze, and clarity were studied. The results show that the optical properties of polymer composites are strongly affected by particle content, particle size, and especially by difference in refractive indices between polymer matrix and particles. It is also revealed that the light transmittance and haze of composites are mainly affected by difference in refractive indices, whereas the clarity is more affected by particle size. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Ring opening polymerization of ε‐caprolactone initiated by decamolybdate anion: Determination of kinetic and thermodynamic parameters by DSC and 1H‐NMR
Authors: Ramírez‐Hernández Aurelio , Martínez‐Richa Antonio
Published: October 2009

The aim of this work is the kinetic and thermodynamic study (by differential scanning calorimetry (DSC) and proton nuclear magnetic resonance (1H‐NMR)) of the polymerization of ε‐caprolactone initiated by ammonium decamolybdate. By means of isothermal kinetics, enthalpies of reaction in the range 150–160°C, as well as constant rates of polymerization (using an nth‐order kinetics function model), were determined. From an Arrhenius plot, activation energy (Ea = 85.3 kJ/mol) and preexponential factor (A = 1.78 × 108 min−1) were estimated. Using dynamic methods, crystallization and melting temperatures for the polymer obtained in situ were derived. Kinetic data for polymerization (obtained by 1H‐NMR) were fitted to 13 different model reaction functions. It was found that power law equations represent better the conversion versus time plots for this system. On the basis of experimental facts, a coordination‐insertion mechanism involving molybdenum(V) species is proposed. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Effect of poly(acrylic acid) molecular mass and end‐group functionality on calcium oxalate crystal morphology and growth
Authors: East Christopher P. , Wallace Andrew D. , Al‐Hamzah Ali , Doherty William O. S. , Fellows Christopher M.
Published: October 2009

A number of series of poly(acrylic acids) (PAA) of differing end‐groups and molecular mass were used to study the inhibition of calcium oxalate crystallization. The effects of the end‐group on crystal speciation and morphology were significant and dramatic, with hexyl‐isobutyrate end groups giving preferential formation of calcium oxalate dihydrate (COD) rather than the more stable calcium oxalate monohydrate (COM), while both more hydrophobic end‐groups and less‐hydrophobic end groups led predominantly to formation of the least thermodynamically stable form of calcium oxalate, calcium oxalate trihydrate. Conversely, molecular mass had little impact on calcium oxalate speciation or crystal morphology. It is probable that the observed effects are related to the rate of desorption of the PAA moiety from the crystal (lite) surfaces and that the results point to a major role for end‐group as well as molecular mass in controlling desorption rate. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Seawater degradable thermoplastic polyurethanes
Authors: Moravek Scott J. , Hassan Mohammad K. , Drake David J. , Cooper Tim R. , Wiggins Jeffrey S. , Mauritz Kenneth A. , Storey Robson F.
Published: October 2009

Degradable thermoplastic polyurethane (TPU) elastomers incorporating poly(D,L‐lactide‐co‐glycolide) (PLGA) were synthesized and characterized. The soft segments consisted of a mixture of poly(butylene adipate) (PBA) and PLGA with PBA/PLGA ratios of 100/0, 75/25, and 50/50 wt %. Two PLGA polyesters were used. BD‐PLGA was initiated from butanediol; whereas BHMBA‐PLGA was initiated from 2,2‐bis‐(hydroxymethyl)butanoic acid. The hard segments consisted of dicyclohexylmethane‐4,4′‐diisocyanate (H12MDI) and 1,4‐butanediol (BD). The hard segment content, expressed as the weight ratio of BD to polyol used in the TPU formulation, was set either at 8 or 12% (31.2 or 38.1% hard segment by weight, respectively). In all cases initial [NCO]/[OH] ratio was 1.03. The tensile modulus of the TPUs ranged from 9 to 131 MPa and ultimate strains ranged from 100 to 750%. DMA was used to probe the thermomechanical transitions of the TPUs and indicated useful application temperatures from well below zero up to 60–80°C depending on the formulation. Hydrolytic degradation of the TPUs was tested in seawater at 37°C. All of the PLGA‐containing TPUs showed enhanced degradation compared to those with only PBA as the soft segment. The latter compositions remained essentially unchanged throughout the test while the PLGA‐containing TPUs lost as much as 45% of their initial mass in 153 days. Molecular weights of TPUs containing degradable polyols were lower than those derived from 100% PBA polyol. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Preparation of anion exchange membrane by amination of chlorinated polypropylene and ethylenediamine and its properties
Authors: Hong Joo‐Hee , Hong Sung‐Kyu
Published: October 2009

An anion exchange membrane was prepared by amination of chlorinated polypropylene (CPP) and ethylenediamine (EDA) at a low temperature and was investigated with respect to not only its physical properties but also its electrochemical properties. The degrees of amination were 46.05, 47.07, 50.56, and 56.58% at 30, 40, 50, and 55°, respectively. The CPP membrane had no water uptake, whereas, that of the CPP‐EDA membrane was 0.153, 0.243, 0.309, and 0.410 g of H2O/g of dry membrane, respectively, with increasing amination. The CPP‐EDA membranes possessed an ion exchange capacity in the range 0.557–1.498 mequiv/g of dry membrane and a fixed ion concentration in the range 4.198–5.114 mequiv/g of H2O. The ionic conductivity of the CPP‐EDA membrane was highest when the water uptake was highest. Those of the CPP‐EDA membrane were in the range 0.475 × 10−2–0.999 × 10−2 S/cm. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Crosslinking of epoxidized natural oils with diepoxy reactive diluents
Authors: Demengeot Emmanuelle‐Anita‐Claude , Baliutaviciene Inga , Ostrauskaite Jolita , Augulis Liudvikas , Grazuleviciene Violeta , Rageliene Lina , Grazulevicius Juozas Vidas
Published: October 2009

The different natural oils epoxidized with 3‐chloroperbenzoic acid were crosslinked with diepoxy reactive diluents, bisphenol A propoxylate diglycidyl ether, and 3,4‐epoxycyclohexylmethyl‐3,4‐epoxyclohexane‐carboxylate, using cationic initiator at 60°C and photoinitiators at the room temperature. The insoluble fraction of the polymeric products was 59–90%. The Young modulus of the crosslinked polymer films ranged from 2 to 861 MPa. The 10% weight loss temperatures of the crosslinked polymers estimated by thermogravimetric analysis were in the range from 250 to 420°C. The water vapor transmission rate of the crosslinked biopolymer films ranged from 6 to 49 g/m2/24 h. Biochemical oxygen demand and biodegradation in soil of the crosslinked polymers were studied. The crosslinked polymers showed higher biodegradation rate than cellulose, starch, and polyvinylalcohol. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Fouling control in a submerged membrane‐bioreactor by the membrane surface modification
Authors: Li Wei , Zhou Jin , Gu Jia‐Shan , Yu Hai‐Yin
Published: October 2009

To improve the antifouling characteristics, polypropylene microporous membranes (PPHFMMs) were surface‐modified by the sequential photoinduced graft polymerization of acrylic acid and acrylamide. The grafting density and the grafting chain length, which played important roles in the antifouling characteristics, were controlled in the first and the second step, respectively. The ATR/FTIR results clearly indicated the successful modification on the membrane surface. The static water contact angle of the modified membrane reduced obviously with the increase of the grafting chain length. The contact angle of the acrylic acid modified membranes was lower than that of the acrylamide modified membrane with similar grafting chain length. The grafting chain length increased with the increase of UV irradiation time and monomer concentration. The grafting chain length of poly(acrylic acid) (PAAc) was lower than that of the polyacrylamide (PAAm) under the same polymerization conditions. Pure water flux for the modified membranes increased with the increase of grafting chain length, and had maximums. The antifouling characteristics of the modified membranes in a submerged membrane‐bioreactor (SMBR) were evaluated. The modified membranes showed better filtration performances in the SMBR than the unmodified membrane, and the acrylic acid grafted membrane presented better antifouling characteristics than acrylamide modified membranes. The results demonstrated that the surface carboxyl‐containing membranes were better than the surface amido‐containing membranes. The results of Pearson correlations demonstrated that the PAAc modified membranes with longer grafting chain length had higher flux recoveries, while the PAAm modified membranes with longer grafting chain length had lower flux recoveries. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Preparation and characterization of novel optically active polyurethanes containing 1,1′‐binaphthol
Authors: Chen Jing , Nan Qiuli , Guo Lingxiang , Zhou Yuming
Published: October 2009

Novel optically active polyurethanes (BPUs) based on chiral 1,1′‐binaphthol were synthesized via direct hydrogen transfer addition polymerization. The polymers were analyzed by FTIR, 1H NMR, DSC‐TGA, CD spectra.The results showed that the specific rotation [α]25D were −78.0° and +54.6° for the S‐BPU and R‐BPU respectively, and these polymers showed better thermal stability. The circular dichroism spectra of the chiral polymers were almost identical except that they gave opposite signals at each wavelength, and the infrared emissivity values of the S‐BPU and R‐BPU were 0.618 and 0.682, they displayed low infrared emissivity. Meantime the polymers implanted with PEG group exhibit better solubility, however thermal stability reduced to some extent. Some properties of the new optically active polyurethanes were reported. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
New binary systems containing TMTD‐amidino phenyl thiourea and CBS–amidinophenyl thiourea for the vulcanization and rheological behavior of natural rubber latex
Authors: Susamma A. P. , Claramma N. M. , Nair Ajalesh B. , Kuriakose A. P.
Published: October 2009

The use of accelerators in rubber latex is basically different from their use in dry rubber. In the present study, N amidino N'phenyl thiourea (APT) which is more nucleophilic than thiourea was studied as a secondary accelerator along with tetra methyl thiuram disulphide (TMTD) and N‐cyclohexylbenzothiazyl sulphenamide (CBS) in the vulcanization of natural rubber latex. These binary systems were found to be very effective in reducing the vulcanization time. The optimum dosages for this non‐toxic secondary accelerator required were derived. Rheological studies of the compounded latex show that the introduction of APT in these systems does not have adverse effect in processing in comparison with the thiourea systems. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Preparation and in vitro release behavior of urapidil hydrochloride loading into microspheres based on poly(L‐lactide)
Authors: Hong Hao , Rongjie Liu , Ting Lan , Genyao Lin
Published: October 2009

Microencapsulation of the antihypertensive drug urapidil hydrochloride was investigated as a means of controlling drug release and minimizing or eliminating local side effects. Poly(L‐lactide) (PLLA) microspheres were prepared using an alternative oil‐in‐water (O/W) solvent‐evaporation method such as the O/W cosolvent solvent‐evaporation method and O/W with various electrolytes added to the aqueous phase method. The surface morphology and the size of the microspheres were observed by scanning electron microscope. Meanwhile, the drug loading efficiency of microspheres and the in vitro release of urapidil hydrochloride from microspheres were performed. The release study indicated that the urapidil hydrochloride‐PLLA microspheres exhibited better sustained release capacity, and the kinetics of urapidil hydrochloride‐PLLA microspheres in vitro release could be described by the Higuchi equation. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Interstitial deletion of 18q: Comparative genomic hybridization array analysis of 46, XX,del(18)(q21.2.q21.33)
Authors: Kato Zenichiro , Morimoto Wataru , Kimura Takeshi , Matsushima Akihiro , Kondo Naomi
Published: October 2009

BACKGROUND: Interstitial deletion of chromosome 18q is rare, making it difficult to assign phenotypes to particular cytogenetic deletions. CASE: We present an 18‐year‐old female with an interstitial deletion of chromosome 18q21.2–q21.33. The clinical features included severe psychomotor retardation with mild growth retardation, hypotonia, midfacial hypoplasia, carp‐shaped mouth, hypertelorism, strabismus, narrow upward slant palpebral fissures, short philtrum, everted lower lip, malformed ears, flat nasal bridge, and epicanthic folds. Brain abnormalities, such as agenesis of the corpus callosum, and abnormalities of the hands and feet were absent. Initially, the deletion was recognized as 18q21.1–q21.31 by conventional chromosomal analysis, and microarray‐based comparative genomic hybridization revealed a 9.6‐Mb deletion at 18q21.2–q21.33. The deletion included the transcription factor 4 gene and the methyl‐CpG binding domain protein 2 (MBD2) gene, but not the MBD1 gene. CONCLUSIONS: The deletion of the transcription factor 4 gene suggested a possible contribution of the deletion to the patient's facial abnormalities, as observed in Pitt‐Hopkins syndrome. Together with other reported cases with interstitial deletion of 18q, a possible contribution of haploinsufficiency in both MBD1 and MBD2 genes to a Rett syndrome‐like phenotype was suggested, but further genetic studies on other cases are necessary to clarify the genotype‐phenotype correlation. Birth Defects Research (Part A), 2010. © 2009 Wiley‐Liss, Inc.
Factors predicting arrest for homeless persons receiving integrated residential treatment for co‐occurring disorders
Authors: Barrett Blake , Young M. Scott , Moore Kathleen , Borum Randy , Ochshorn Ezra
Published: October 2009

Background Homeless individuals are at increased risk for health and criminal justice problems.

Aims The aim of this study was to examine risk factors affecting arrest rates in a cohort of homeless people with co‐occurring psychiatric and substance‐abuse disorders.

Methods Baseline data were collected from 96 homeless individuals residing in a residential treatment facility for people with co‐occurring disorders. Arrest data were obtained for 2 years following treatment intake. Regression analyses were employed to examine interactions between study variables.

Results One third of the sample was arrested during the 2‐year follow‐up period, principally for drug offences. People referred to treatment directly from the criminal justice system were four times more likely to re‐offend than those referred from other sources. Participants' perceived need for mental‐health services reduced risk of arrest while their perception of medical needs increased this risk.

Conclusions The relationship between referral from a criminal justice source and re‐arrest after admission to the treatment facility is unsurprising, and consistent with previous literature, but the suggestion of an independently increased risk in the presence of perceived physical health‐care needs is worthy of further study. The lower risk of arrest for people who perceive that they have psychological needs is encouraging. Copyright © 2009 John Wiley & Sons, Ltd.
Low internalised restraint predicts criminal recidivism in young female prisoners
Authors: Kjelsberg Ellen , Rustad Åse‐Bente , Karnik Niranjan
Published: October 2009

Background The Weinberger Adjustment Inventory (WAI) measures social‐emotional adjustment along two dimensions: distress and restraint. Four types of adjustment according to this measure have been shown to correlate with criminal recidivism among young male prisoners: reactive (high distress, low restraint), suppressor (high distress, high restraint), non‐reactive (low distress, low restraint) and repressor (low distress, high restraint).

Aim To evaluate the predictive potential of the WAI among young female prisoners.

Methods Women under 30 years old, consecutively admitted to one of three Norwegian prisons, were asked to complete the WAI. Most of those eligible (102, 94%) did so. Re‐conviction data were collected from the National Crime Register 38 months (SD = 9.0) after release.

Results The overall re‐conviction rate was 38%. Rates differed according to the four WAI types: 53% in the non‐reactive, 50% in the reactive, 22% in the suppressor and 11% in the repressor group (p = 0.006). Kaplan–Meier analyses showed that group differences were explained by the WAI restraint dimension (p = 0.008). Differences on the distress dimension did not influence re‐conviction. Cox regression analysis (adjusting for age at first court conviction and prior offences) found that women with low restraint scores were almost three times as likely to re‐offend as women with high restraint scores.

Conclusion The WAI appears to be an effective tool for identifying women who are particularly vulnerable to re‐offending. Evidence of high capacity for restraint is protective, regardless of distress levels and even after adjusting for the effect of other criminologically important factors. The findings are suggestive that there may be value in individualising ‘treatment’ or rehabilitation programmes for prisoners. Copyright © 2009 John Wiley & Sons, Ltd.
Cisplatin Adducts on a GGG Sequence within a DNA Duplex Studied by NMR Spectroscopy and Molecular Dynamics Simulations
Authors: Téletchéa Stéphane , Skauge Tormod , Sletten Einar , Kozelka Jiří
Published: October 2009

The antitumor drug cisplatin (cis‐[PtCl2(NH3)2]) reacts with cellular DNA to form GG intrastrand adducts between adjacent guanines as predominant lesions. GGG sites have been shown to be hotspots of platination. To study the structural perturbation induced by binding of cisplatin to two adjacent guanines of a GGG trinucleotide, we examined here the decanucleotide duplex d[(G1C2C3${{\rm G}{{{\ast}\hfill \atop 4\hfill}}}$${{\rm G}{{{\ast}\hfill \atop 5\hfill}}}$G6T7‐ C8G9C10)⋅d(G11C12G13A14C15C16C17G18‐ G19C20)] (dsCG*G*G) intrastrand cross‐linked at the G* guanines by cis‐{Pt(NH3)2}2+ using NMR spectroscopy and molecular dynamics (MD) simulations. The NMR spectra of dsCG*G*G were found to be similar to those of previously characterized DNA duplexes cross‐linked by cisplatin at a pyG*G*X site (py=pyrimidine; X=C, T, A). This similarity of NMR spectra indicates that the base at the 3′‐side of the G*G*–Pt cross‐link does not affect the structure to a large extent. An unprecedented reversible isomerization between the duplex dsCG*G*G (bearing a ${{\rm G}{{{\ast}\hfill \atop 4\hfill}}}$${{\rm G}{{{\ast}\hfill \atop 5\hfill}}}$–Pt chelate) and duplex dsGG*G*T (bearing a ${{\rm G}{{{\ast}\hfill \atop 5\hfill}}}$${{\rm G}{{{\ast}\hfill \atop 6\hfill}}}$–Pt chelate) was observed, which yielded a 40:60 equilibrium between the two intrastrand GG–Pt cross‐links. No formation of interstrand cross‐links was observed. NMR spectroscopic data of dsCG*G*G indicated that the deoxyribose of the 5′‐G* adopts an N‐type conformation, and the cytidines C3, C15, and C16 have average phase angles intermediate between S and N. The NMR spectroscopic chemical shifts of dsGG*G*T showed some fundamental differences to those of pyG*G*–platinum adducts but were in agreement with the NMR spectra reported previously for the DNA duplexes cross‐linked at an AG*G*C sequence by cisplatin or oxaliplatin. The presence of a purine instead of a pyrimidine at the 5′‐side of the G*G* cross‐link seems therefore to affect the structure of the XG* step significantly.
Multiple Reaction Pathways in Rhodium‐Catalyzed Hydrosilylations of Ketones
Authors: Schneider Nathanaëlle , Finger Markus , Haferkemper Christian , Bellemin‐Laponnaz Stéphane , Hofmann Peter , Gade Lutz H.
Published: October 2009

A detailed density functional theory (DFT) computational study (using the BP86/SV(P) and B3LYP/TZVP//BP86/SV(P) level of theory) of the rhodium‐catalyzed hydrosilylation of ketones has shown three mechanistic pathways to be viable. They all involve the generation of a cationic complex [LnRhI]+ stabilized by the coordination of two ketone molecules and the subsequent oxidative addition of the silane, which results in the Rh–silyl intermediates [LnRhIII(H)SiHMe2]+. However, they differ in the following reaction steps: in two of them, insertion of the ketone into the RhSi bond occurs, as previously proposed by Ojima et al., or into the SiH bond, as proposed by Chan et al. for dihydrosilanes. The latter in particular is characterized by a very high activation barrier associated with the insertion of the ketone into the SiH bond, thereby making a new, third mechanistic pathway that involves the formation of a silylene intermediate more likely. This “silylene mechanism” was found to have the lowest activation barrier for the rate‐determining step, the migration of a rhodium‐bonded hydride to the ketone that is coordinated to the silylene ligand. This explains the previously reported rate enhancement for R2SiH2 compared to R3SiH as well as the inverse kinetic isotope effect (KIE) observed experimentally for the overall catalytic cycle because deuterium prefers to be located in the stronger bond, that is, CD versus MD.
Small interfering RNA‐mediated down‐regulation of SPAG9 inhibits cervical tumor growth
Authors: Garg Manoj , Kanojia Deepika , Suri Sushma , Suri Anil
Published: October 2009

BACKGROUND:

The expression of the SPAG9 is associated with various human malignancies. Earlier work revealed a significant association of SPAG9 expression with the early spread of cervical cancer, making it an attractive therapeutic target. Here, the authors investigated the role of SPAG9 in carcinogenesis of squamous cell carcinoma (SCC) of the cervix. Furthermore, they sought to determine whether ablation of SPAG9 expression reduces the tumor growth of cervical SCC in vivo.

METHODS:

A plasmid‐based small interfering RNA approach was used to specifically knock down the expression of SPAG9 in SiHa cells derived from SCC of the cervix in vitro and in vivo. Reverse transcriptase polymerase chain reaction, immunofluorescence staining, flow cytometry, cellular growth, colony formation, migration, invasion, and wound healing assays were studied to characterize SPAG9 in vitro. Furthermore, a cervical cancer xenograft model in nude mice was established to investigate whether knockdown of SPAG9 reduces the tumor growth of cervical SCC in vivo.

RESULTS:

The results demonstrated that silencing the SPAG9 by small interfering RNA resulted in inhibition of cell growth, colony formation, migration, and invasion. The authors showed for the first time that the knockdown of SPAG9 expression by small interfering RNA significantly suppressed the tumor growth of cervical SCC in vivo.

CONCLUSIONS:

These results suggest that SPAG9 expression may play a pivotal role in tumor growth and could contribute to the early spread of cervical cancer. Small interfering RNA‐mediated down‐regulation of SPAG9 represents a promising therapeutic approach for the treatment of cervical cancer. Cancer 2009. © 2009 American Cancer Society.
Amifostine does not prevent platinum‐induced hearing loss associated with the treatment of children with hepatoblastoma
Authors: Katzenstein Howard M. , Chang Kay W. , Krailo Mark , Chen Zhengjia , Finegold Milton J. , Rowland Jon , Reynolds Marleta , Pappo Alberto , London Wendy B. , Malogolowkin Marcio
Published: October 2009

BACKGROUND:

The current study was conducted to determine whether amifostine is effective in reducing the toxicities associated with the administration of platinum‐containing regimens in children with hepatoblastoma (HB).

METHODS:

Patients were enrolled on P9645 beginning in March of 1999. Patients who had stage I/II disease received treatment with 4 cycles of combined cisplatin, 5‐fluorouracil, and vincristine (C5V) with or without amifostine. Patients who had stage III/IV disease were randomized to receive treatment with 6 cycles of either C5V with or without amifostine or carboplatin alternating with cisplatin (CC) with or without amifostine. Patients who were randomized to receive amifostine were given a dose of 740 mg/m2 intravenously over 15 minutes before each administration of a platinum agent.

RESULTS:

Eighty‐two patients were considered in a special interim analysis of the incidence of toxicity. The disease outcome for patients who received amifostine was similar to the outcome for patients who did not receive amifostine (P = .22). The incidence of significant hearing loss (>40 dB) was similar for patients who did or did not receive amifostine (38% [14 of 37 patients] vs 38% [17 of 45 patients], respectively; P = .68). There were no differences in the incidence of renal or bone marrow toxicities evaluated. Patients who received amifostine had a higher incidence of hypocalcemia (5% vs 0.5%; P = .00006).

CONCLUSIONS:

Amifostine in the doses and schedule used in this study failed to significantly reduce the incidence of platinum‐induced toxicities in patients with HB. Cancer 2009. © 2009 American Cancer Society.
Hepatoblastoma, cisplatin, and ototoxicity
Authors: Sullivan Michael J.
Published: October 2009

Young infants with hepatoblastoma now have an excellent chance of cure, but many will be left with significant cisplatin‐related hearing loss, which may impair their language and social development and may affect later learning with a lifetime of hearing loss. A report from the Children's Oncology Group of a randomized trial of amifostine for the prevention of platinum‐related toxicity in infants with hepatoblastoma demonstrated that amifostine has no benefit in reducing cisplatin ototoxicity. Several new agents, such as sodium thiosulfate, currently are entering clinical trials as otoprotectants; however, as the goal for some childhood malignancies shifts from disease cure to enhancing the quality of long‐term survival, there is a need to ensure that the design and conduct of cancer‐control trials are as rigorous as those directed toward curing disease.
What's in a name? Evidence that Papanicolaou, not Babes, deserves credit for the PAP test
Authors: Diamantis A. , Magiorkinis E. , Androutsos G.
Published: October 2009

The purpose of our study is to elaborate on the ongoing controversy regarding the origination of the Pap test between the supporters of George Papanicolaou and Aurel Babes. We studied the original articles published by Aurel Babes and George Papanicolaou and conducted a comparative evaluation of both methods. Babes' method is radically different from Papanicolaou's method. Differences included the sampling method, the fixation and staining technique, and the interpretation of the results regarding cases of cervical cancer. We conclude that theestablishment of the technique in clinical practice and the ideaof its application as preventive control of cervical cancer belong solely to George Papanicolaou. Diagn. Cytopathol. 2010. © 2009 Wiley‐Liss, Inc.
Captivity reduces hippocampal volume but not survival of new cells in a food‐storing bird
Authors: Tarr Bernard A. , Rabinowitz Jeremy S. , Imtiaz Mubdiul Ali , DeVoogd Timothy J.
Published: October 2009

In many naturalistic studies of the hippocampus wild animals are held in captivity. To test if captivity itself affects hippocampal integrity, adult black‐capped chickadees (Poecile atricapilla) were caught in the fall, injected with bromodeoxyuridine to mark neurogenesis, and alternately released to the wild or held in captivity. The wild birds were recaptured after 4–6 weeks and perfused simultaneously with their captive counterparts. The hippocampus of captive birds was 23% smaller than wild birds, with no hemispheric differences in volume within groups. Between groups there was no statistically significant difference in the size of the telencephalon, or in the number and density of surviving new cells. Proximate causes of the reduced hippocampal volume could include stress, lack of exercise, diminished social interaction, or limited caching opportunity—a hippocampal‐dependent activity. The results suggest the avian hippocampus—a structure essential for rapid, complex relational and spatial learning—is both plastic and sensitive, much as in mammals, including humans. © 2009 Wiley Periodicals, Inc. Develop Neurobiol, 2009
Convergence of multisensory inputs in Xenopus tadpole tectum
Authors: Hiramoto Masaki , Cline Hollis T.
Published: October 2009

The integration of multisensory information takes place in the optic tectum where visual and auditory/mechanosensory inputs converge and regulate motor outputs. The circuits that integrate multisensory information are poorly understood. In an effort to identify the basic components of a multisensory integrative circuit, we determined the projections of the mechanosensory input from the periphery to the optic tectum and compared their distribution to the retinotectal inputs in Xenopus laevis tadpoles using dye‐labeling methods. The peripheral ganglia of the lateral line system project to the ipsilateral hindbrain and the axons representing mechanosensory inputs along the anterior/posterior body axis are mapped along the ventrodorsal axis in the axon tract in the dorsal column of the hindbrain. Hindbrain neurons project axons to the contralateral optic tectum. The neurons from anterior and posterior hindbrain regions project axons to the dorsal and ventral tectum, respectively. While the retinotectal axons project to a superficial lamina in the tectal neuropil, the hindbrain axons project to a deep neuropil layer. Calcium imaging showed that multimodal inputs converge on tectal neurons. The layer‐specific projections of the hindbrain and retinal axons suggest a functional segregation of sensory inputs to proximal and distal tectal cell dendrites, respectively. © 2009 Wiley Periodicals, Inc. Develop Neurobiol, 2009