bluuebunny/crossref_metadata_2025_split huggingface dataset:
Confirmation of the association between a polymorphism in the promoter region of the prodynorphin gene and cocaine dependence
Authors: Dahl John P. , Weller Andrew E. , Kampman Kyle M. , Oslin David W. , Lohoff Falk W. , Ferraro Thomas N. , O'Brien Charles P. , Berrettini Wade H. 
Published: September 2005

AbstractThe endogenous opioid system has been shown to have a role in the biological processes involved in addiction to numerous drugs of abuse including cocaine. It has recently been reported that the variable nucleotide tandem repeat (VNTR) polymorphism in the 5′ promoter region of the prodynorphin gene, which encodes the precursor for three endogenous opioid peptides, is associated with the cocaine dependent phenotype. In order to confirm this finding, we genotyped the prodynorphin promoter polymorphism in cocaine dependent (n = 167) and control (n = 88) individuals of African descent. The results from this experiment indicate a statistically significant (χ2 = 5.64, OR = 1.59, P = 0.018) association between the prodynorphin promoter VNTR polymorphism and the cocaine dependent phenotype. In contrast to previous work showing increased risk conferred by one or two copies of the prodynorphin VNTR, the genotyping results from this study indicate that persons with three or four copies of this polymorphism are more likely to become cocaine dependent. This disparity suggests that the prodynorphin promoter VNTR may not be the functional polymorphism associating with the cocaine dependent phenotype. It is possible that different alleles of the prodynorphin promoter VNTR in the independent populations used for this and the previous study may be in linkage disequilibrium with a yet to be identified functional polymorphism in this gene. © 2005 Wiley‐Liss, Inc.
Abnormal elevation ofFMR1mRNA is associated with psychological symptoms in individuals with the fragile X premutation
Authors: Hessl David , Tassone Flora , Loesch Danuta Z. , Berry‐Kravis Elizabeth , Leehey Maureen A. , Gane Louise W. , Barbato Ingrid , Rice Cathlin , Gould Emma , Hall Deborah A. , Grigsby James , Wegelin Jacob A. , Harris Susan , Lewin Foster , Weinberg Dahlia , Hagerman Paul J. , Hagerman Randi J. 
Published: September 2005

AbstractUntil recently, individuals with premutation alleles (55–200 CGG repeats) of the fragile X mental retardation 1 (FMR1) gene were believed to be psychologically unaffected. However, the recent documentation of abnormal elevation ofFMR1mRNA, discovery of fragile X‐associated tremor/ataxia syndrome (FXTAS), and reports of psychiatric disorders in children and adults with the premutation have suggested a pathogenic gene–brain–behavior mechanism. In a large collaborative study, 68 men and 144 women with theFMR1premutation completed a psychological symptoms checklist andFMR1genetic testing, including determination of CGG repeat size, percentage ofFMR1protein (FMRP)‐positive lymphocytes, andFMR1mRNA levels. Relative to published norms, men and women with FXTAS symptoms reported higher levels of several types of psychological symptoms. In addition, men and women with the premutation and no overt evidence of FXTAS reported higher levels of obsessive‐compulsive symptoms. ElevatedFMR1mRNA, but not CGG repeat size or reduced FMRP (as measured by immunocytochemistry), was significantly associated with increased psychological symptoms, predominantly obsessive‐compulsive symptoms and psychoticism, in premutation men with and without FXTAS symptoms. There was no relationship between CGG repeat size,FMR1mRNA or FMRP and psychological symptoms in premutation women unless the sample was restricted to those with skewed X‐activation ratio toward >50% active premutation alleles. The results of this study support the hypothesis thatFMR1function is associated with psychological difficulties in individuals with the premutation, and provide evidence concordant with an RNA toxic gain‐of‐function model in a neuropsychiatric phenotype. © 2005 Wiley‐Liss, Inc.
A regular, hydrophobically modified polyampholyte as novel pour point depressant
Authors: Kudaibergenov Sarkyt E. , Didukh Alexander G. , Ibraeva Zhanar E. , Bimendina Larisa A. , Rullens Francois , Devillers Michel , Laschewsky André 
Published: September 2005

AbstractA new regular polyampholyte, namely poly(N,N‐diallyl‐N‐octadecylamine‐alt‐(maleic acid)), was studied as an additive to crude oil. The amphiphilic polyampholyte proved to be an efficient pour point depressant, to inhibit the deposition of wax, and to improve the viscosity of waxy crude oil from the Akshabulak oilfield (Western Kazakhstan). On optimizing the concentration of the polymer, both the kinematical viscosity and the pour point of waxy crude oils were found to be strongly decreased. The morphology of the paraffin aggregates formed was compared before and after heat treatment of the waxy crude oils, in the presence and the absence of the polymer. The rheological characteristics of the waxy crude oil were markedly improved, in particular, by decreasing the plastic viscosity and the yield stress values upon addition the polymer. The inhibition of wax deposits in the presence of the amphiphilic polyampholyte was interpreted in terms of its interference with the wax crystallization process because of the formation of inverse micellar structures. Although the interaction of the cationic and the anionic groups on the polymer backbone stabilizes the smaller size of the aggregates, the hydrophobic side chains of the polymer provide nucleation sites and cocrystallize with the paraffins, thus modifying the paraffin crystal structure. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 2101–2108, 2005
Effect of single yarn twist and ply to single yarn twist ratio on strength and elongation of ply yarns
Authors: Palaniswamy N. K. , Mohamed A. Peer 
Published: September 2005

AbstractThe amount of ply twist required to bring the surface fibers of the strand parallel to ply yarn axis is half the single yarn twist and, is experimentally verified by viewing the multifilament yarns longitudinally under Scanning Electron Microscope. The effect of single yarn twist and ply to single yarn twist ratio on strength and elongation of two‐ply cotton yarn have been studied. As the single yarn twist increases the tensile strength of the ply yarns with different levels of ply to single yarn twist ratio increases and at 130–140% of normal single yarn twist level, the ply yarns attain almost the same strength. Rate of improvement in tensile strength of cotton two‐ply yarn with respect to single yarn twist is more than that with respect to ply twist. The effect of ply to single yarn and cable to ply yarn twist ratio on strength and elongation of ply and cable multifilament yarns have been studied. Tensile strength of ply and cable multifilament yarns do not vary with the change in ratio of ply to single yarn twist and cable to ply twist respectively, particularly when the resultant yarn is finer. The cosine of average filament inclination to the ply yarn axis and that to the cable yarn axis do not vary much with different levels of ply to single yarn twist ratio and cable to ply yarn twist ratio respectively. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 2245–2252, 2005
Filled temperature‐sensitive poly(vinyl methyl ether) hydrogels
Authors: Theiss Daniel , Schmidt Thomas , Dorschner Helmut , Reichelt Rudolf , Arndt Karl‐Friedrich 
Published: September 2005

AbstractTemperature‐sensitive hydrogels based on poly(vinyl methyl ether) (PVME) with ferroelectric or ferromagnetic properties were synthesized by high‐energy irradiation. Barium titanate and poly(vinylidene fluoride) (PVDF) were used as ferroelectric filler and Ni as ferromagnetic filler. The filled PVME hydrogels were synthesized by electron beam or γ‐ray irradiation (of a suspension with 5–50 wt % of filler (with respect to polymer mass) in a 20 wt % aqueous PVME solution). Filling of the gel reduces the absolute swelling degree at low temperatures, but do not influence the phase‐transition temperature of the gel. The particle distribution of the fillers inside the gel was visualized by field emission scanning electron microscopy. The fillers were incorporated in the PVME network and fixed because of their size (inorganic particles), as well as by chemical bonds (PVDF). The ferroelectric or ferromagnetic properties of the filled gels were proved. Measurements in a corresponding alternating field provide the hysteresis loop, for both the ferromagnetic and ferroelectric gel. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 2253–2265, 2005
Polystyrene nanocomposite materials: Preparation, morphology, and mechanical, electrical, and thermal properties
Authors: Ma Chen‐Chi M. , Chen Yi‐Jie , Kuan Hsu‐Chiang 
Published: September 2005

AbstractIn this study, we prepared polystyrene (PS) resin nanocomposites with antistatic properties by melt‐blending PS with nanoscale zinc oxide (ZnO). The effects of nanoscale ZnO on the electrical and physical characteristics of the PS nanocomposites were investigated. Two kinds of nanoscale powders, spherical zinc oxide (s‐ZnO) and zinc oxide whisker (w‐ZnO), were selected. The coupling agents vinyltriethoxysilane (VTES) and phenyltriethoxysilane (PTES) were used to improve the compatibility between the nanopowders and PS resin. The addition of s‐ZnO and w‐ZnO improved the antistatic characteristics of the materials. The surface resistivities of the s‐ZnO and w‐ZnO nanocomposites were significantly reduced by modification with VTES and PTES. The addition of ZnO nanopowder increased the flexural modulus and reduced the flexural strength. The silane coupling agents improved the flexural properties of the nanocomposites. The glass‐transition temperatures and thermal degradation temperatures of the ZnO/PS nanocomposites increased with ZnO content. Treatment with silane increased the glass‐transition temperatures and thermal degradation temperatures of the composites. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 2266–2273, 2005
Preparation and characterization of UV‐curable MPS‐modified silica nanocomposite coats
Authors: Li Fusheng , Zhou Shuxue , Wu Limin 
Published: September 2005

AbstractA series of UV‐curable nanocomposites were prepared with 3‐(trimethoxysilyl) propyl methacrylate (MPS) modified nanosilica under the initiation of 2,2‐dimethoxy‐1,2‐diphenylethan‐1‐one. It was found that MPS‐modified nanosilica together with free MPS could form transparent nanocomposite coats. As the particle size of nanosilica increased, the photopolymerization rate, final double bond conversion, and tack‐free time of nanocomposites increased while the surface roughness, glass‐transition temperature, and UV absorbance of nanocomposites decreased. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 2274–2281, 2005
Preparation of sulfur‐modified powdered polychloroprene rubber by inverse coagulation
Authors: Zhang Anqiang , Wang Lianshi , Lin Yaling 
Published: September 2005

AbstractSulfur‐modified powdered polychloroprene rubber (PCR‐121) was prepared by inverse coagulation. A new coating agent (SN) was developed that could generate in situ the coating layer by inverse coagulation. The results show that this is a low‐cost, stable technology for the production of powdered rubber with a very low coating agent content. A powdering model based on the liquid–liquid stirring theory of noncoalescing, liquid–liquid dispersion was proven with uniform design testing. According to this model, the mass fraction of medium‐scale particles (1–3 mm) was only related to the agitation speed in the experimental range. Scanning electron microscopy (SEM) analysis showed that the PCR‐121 particles were single continuous particles coagulated from single chloroprene rubber latex drops. Energy spectrum analysis showed that a layer with higher Ca content was coated at the surface of PCR‐121 particles, which made PCR‐121 a free‐flowing powdered rubber. The results show that the variation of Mooney viscosity (ML1+4 100°C) from 30 to 130 had no obvious effect on the mechanical properties of PCR‐121. Compared with bale CR121, PCR‐121 had better mechanical properties. SEM analysis and energy spectrum analysis on the tensile fracture surfaces showed that the dispersion of compounding agents in PCR‐121 was better than that in bale CR121, which resulted in better mechanical properties in PCR‐121. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 2109–2115, 2005
Methoxy poly(ethylene glycol)‐b‐poly(L‐lactic acid) copolymer nanoparticles as delivery vehicles for paclitaxel
Authors: Deng Liandong , Li Aigui , Yao Chunmei , Sun Duoxian , Dong Anjie 
Published: September 2005

AbstractMethoxy poly(ethylene glycol)‐b‐poly(L‐lactic acid) (MPELLA) was prepared by the melt polycondensation of methoxy poly(ethylene glycol) and L‐lactic acid. The structure and properties of MPELLA were characterized by IR, 1H‐NMR, differential scanning calorimetry, and wide‐angle X‐ray diffraction. To estimate its feasibility as a vehicle for paclitaxel, MPELLA nanoparticles were prepared by a self‐emulsification/solvent evaporation method. The paclitaxel‐loaded nanoparticles (PMTs) showed a spherical morphology with an inner core and an outer shell. The size, size distribution, and loading capacity of PMTs were also measured. The release kinetics of paclitaxel from PMTs in vitro was studied. The results show that paclitaxel can be effectively incorporated into MPELLA nanoparticles, which provide a delivery system for paclitaxel and other hydrophobic or toxic compounds. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 2116–2122, 2005
Polyetherols from isocyanuric acid and propylene carbonate
Authors: Węglowska Elwira , Lubczak Jacek 
Published: September 2005

AbstractA new method for the synthesis of polyetherols containing perhydro‐1,3,5‐triazine rings by the reaction of isocyanuric acid and an excess of propylene carbonate is described. The reaction was studied in the presence of various catalysts and with varying substrate molar ratios. The structures and physical properties of the products were also studied. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 2130–2138, 2005
Synthesis and characterization of polyurethane anionomers
Authors: Matsunaga Katsuji , Nakagawa Kazuko , Sawai Satoshi , Sonoda Osamu , Tajima Masahiro , Yoshida Yasuhiko 
Published: September 2005

AbstractUn‐ionized polyurethane was obtained by the reaction of an isocyanate‐terminated urethane prepolymer, which was synthesized from 4,4′‐diphenylmethane diisocyanate and poly(oxytetramethylene)‐α,ω‐glycol, with 2,2‐bis(hydroxymethyl)propionic acid. A carboxylate‐based polyurethane anionomer was then derived from the polyurethane by the use of the sodium, potassium, or magnesium salt of acetic acid as a neutralizer. The ionomerization resulted in the following changes in the characteristics of the polyurethane: (1) an increase in the tensile strength, (2) a decrease in the glass‐transition temperature, (3) an increase in the wettability and hygroscopicity with respect to water, and (4) susceptibility to thermal decomposition. A sulfonate‐based polyurethane was also synthesized for comparison with the carboxylate‐based polyurethane. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 2144–2148, 2005
Radiation‐induced grafting of pentamethyl hindered amine light stabilizer 1,2,2,6,6‐pentamethyl‐4‐piperidinyl methacrylate onto polypropylene
Authors: Wang Huiliang 
Published: September 2005

AbstractThe γ‐radiation‐induced grafting of 1,2,2,6,6‐pentamethyl‐4‐piperidinyl methacrylate (PMPM) onto polypropylene (PP) was investigated with a simultaneous irradiation technique. The effects of the solvent, dose, monomer concentration, and photoinitiator on the grafting were investigated. The grafting was easier in a benzene solution than in chloroform and acetone solutions. The grafting percentage first increased almost linearly with the irradiation dose until 20 kGy and then increased slowly or remained constant. The grafting percentage increased with the monomer concentration until 1.1 mol/L. The grafting percentage was higher when the proper amount of benzophenone was added. The grafted samples were characterized with Fourier transform infrared spectroscopy and thermogravimetric analysis. Carbonyl groups were found on grafted PP samples, and the carbonyl index increased with the grafting percentage. Thermogravimetric analyses proved the existence of grafted materials on PP, and grafted PMPM thermally decomposed at a lower temperature than PP. The radiation resistance of PP with grafted PMPM was better than that of pristine PP. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 2157–2164, 2005
Effects of the polybutadiene/poly(styrene‐co‐acrylonitrile) ratio in a polybutadiene‐g‐poly(styrene‐co‐acrylonitrile) impact modifier on the morphology and mechanical behavior of acrylonitrile–butadiene–styrene blends
Authors: Xu X. F. , Yang H. D. , Zhang H. X. 
Published: September 2005

AbstractPolybutadiene‐g‐poly(styrene‐co‐acrylonitrile) (PB‐g‐SAN) impact modifiers with different polybutadiene (PB)/poly(styrene‐co‐acrylonitrile) (SAN) ratios ranging from 20.5/79.5 to 82.7/17.3 were synthesized by seeded emulsion polymerization. Acrylonitrile–butadiene–styrene (ABS) blends with a constant rubber concentration of 15 wt % were prepared by the blending of these PB‐g‐SAN copolymers and SAN resin. The influence of the PB/SAN ratio in the PB‐g‐SAN impact modifier on the mechanical behavior and phase morphology of ABS blends was investigated. The mechanical tests showed that the impact strength and yield strength of the ABS blends had their maximum values as the PB/SAN ratio in the PB‐g‐SAN copolymer increased. A dynamic mechanical analysis of the ABS blends showed that the glass‐transition temperature of the rubbery phase shifted to a lower temperature, the maximum loss peak height of the rubbery phase increased and then decreased, and the storage modulus of the ABS blends increased with an increase in the PB/SAN ratio in the PB‐g‐SAN impact modifier. The morphological results of the ABS blends showed that the dispersion of rubber particle in the matrix and its internal structure were influenced by the PB/SAN ratio in the PB‐g‐SAN impact modifiers. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 2165–2171, 2005
Biocompatible polymer blends: Effects of physical processing on the molecular interaction of poly(vinyl alcohol) and poly(vinyl pyrrolidone)
Authors: Jones S. A. , Martin G. P. , Royall P. G. , Brown M. B. 
Published: September 2005

AbstractBlending is a very effective method for manufacturing new polymeric materials; however, the process used to combine two polymers can influence the physicochemical properties of the final product. As such, the aim of this study was to investigate how the rapid removal of a solvent from a composite by the spray drying of partially hydrolyzed poly(vinyl alcohol) (PVA)/poly(vinyl pyrrolidone) (PVP) altered the solid‐state properties of the material compared to casting the blend within a film. Although thermal analysis showed that PVP acted as a plasticizer, reducing the melting point of PVA, spray drying the product rather than using a film‐casting procedure improved its solid‐state stability (increasing the glass transition) and resulted in the formation of a second crystalline phase within the material. Spectroscopic studies suggested that the manufacturing‐induced variance in the solid‐state properties of the PVA/PVP blends originated from structural differences in the composite caused by the processing method employed to form the blend. Although blending should still be considered a viable method of generating novel polymeric material, this study illustrated that through careful manipulation of the actual manufacturing process, the solid‐state properties of the product can be altered. This could open a whole range of novel applications for traditionally used polymer composites. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 2290–2299, 2005
Melting behavior and nonisothermal crystallization kinetics of polyamide 6/polyamide 66 molecular composites via in situ polymerization
Authors: Li Yulin , Liu Hongzhi , Zhang Ying , Yang Guisheng 
Published: September 2005

AbstractThe melting behavior and nonisothermal crystallization kinetics of pure polyamide 6 (PA 6) and its molecular composites with polyamide 66 (PA 66) were investigated with differential scanning calorimetry. The PA 6/PA 66 composites had one melting peak, whereas the coextruded PA 6/PA 66 blends had two melting peaks. With the addition of PA 66 to PA 6 via in situ anionic polymerization, the melting temperature, crystallization temperature, and crystallinity of PA 6 in the composites decreased. The half‐time of nonisothermal crystallization increased for a PA 6/PA 66 molecular composite containing 12 wt % PA 66, in comparison with that of pure PA 6. The commonly used Ozawa equation was used to fit the nonisothermal crystallization of pure PA 6 and its composites. The Ozawa exponent values in the primary stage were equal to 1.28–3.03 and 1.28–2.97 for PA 6 and its composite with 12 wt % PA 66, respectively, and this revealed that the mechanism of primary crystallization of PA 6 and PA 6/PA 66 was mainly heterogeneous nucleation and growth. All the results indicated that the incorporation of PA 66 into PA 6 at the molecular level retarded the crystallization of PA 6. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 2172–2177, 2005
Changes in the microstructure and characteristics of carbon/carbon composites with mesophase mesocarbon microbeads added during graphitization
Authors: Hu Hsien‐Lin , Ko Tse‐Hao , Kuo Wen‐Shyong 
Published: September 2005

AbstractCarbon/carbon (C/C) composites were prepared from oxidative PAN fiber felts, a resol‐type phenolic resin, and mesophase pitch derived from coal tar. In this study, the effects on mesocarbon microbeads (MCMBs), flexural strength, flexural moduli, electric conductivity, and thermal conductivity of C/C composites with a mesophase content ranging from 0 to 30 wt % were examined during pyrolysis. The results show that the C/C composite with the addition of 10–30 wt % mesophase had a higher density, greater stacking size, and higher preferred orientation than the C/C composites without any mesophase during heat treatment. These composites also exhibited an improvement in flexural strength from 19.7 to 30.3%. The flexural moduli of these composites with mesophase added increased by 15.1 to 31.3% compared to that with no mesophase added. These composites also showed improved electric conductivity, from 15.1 to 43.7%, and thermal conductivity, from 12 to 31.3%. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 2178–2190, 2005