bluuebunny/crossref_metadata_2025_split huggingface dataset:
Morphological analyses and 3D modeling of the tongue musculature of the chimpanzee (Pan troglodytes)
Authors: Takemoto Hironori 
Published: July 2008

AbstractKnowledge of the comparative anatomy of tongue musculature is crucial to the discussion of the origin and the evolution of speech because of the indispensable role played by this organ in speech. However, the tongue musculature of primates has rarely been studied. In a previous study, the author analyzed human tongue musculature and developed a 3D model of this organ [Takemoto, Journal of Speech, Language, and Hearing Research 44:95–107, 2001]. In this study, the tongue musculature of chimpanzees was examined using methods similar to those used for humans. Results showed that tongue musculature was topologically the same for both humans and chimpanzees. As in humans, the tongue musculature of chimpanzees consisted of inner and outer regions. The inner musculature was composed of serial “structural units,” made up of two types of laminae whose fibers were perpendicular to the tongue surface. The outer musculature was a thin layer of fibers oriented parallel to the surface and superficial to the inner musculature. Although the tongue musculature of humans and chimpanzees is similar, the external shapes differ: the chimpanzee tongue is flat, whereas the human tongue is round. Applying the muscular hydrostat theory to the external shape of the tongue suggests that the primary actions of the chimpanzee tongue are protrusion and retrusion, whereas the human tongue can be deformed in the oral cavity with a high degree of freedom. It is hypothesized that the evolution of the external shape of the tongue is one of the factors that led to the development of human speech. The results of this study suggest that modeling based on muscular hydrostatic theory of the effects of changes in external tongue shape on articulatory movements should be included in discussions on the origin of speech. Am. J. Primatol. 70:966–975, 2008. © 2008 Wiley‐Liss, Inc.
Distribution of Y chromosomes among native North Americans: A study of Athapaskan population history
Authors: Singh Malhi Ripan , Gonzalez‐Oliver Angelica , Schroeder Kari Britt , Kemp Brian M. , Greenberg Jonathan A. , Dobrowski Solomon Z. , Smith David Glenn , Resendez Andres , Karafet Tatiana , Hammer Michael , Zegura Stephen , Brovko Tatiana 
Published: July 2008

AbstractIn this study, 231 Y chromosomes from 12 populations were typed for four diagnostic single nucleotide polymorphisms (SNPs) to determine haplogroup membership and 43 Y chromosomes from three of these populations were typed for eight short tandem repeats (STRs) to determine haplotypes. These data were combined with previously published data, amounting to 724 Y chromosomes from 26 populations in North America, and analyzed to investigate the geographic distribution of Y chromosomes among native North Americans and to test the Southern Athapaskan migration hypothesis. The results suggest that European admixture has significantly altered the distribution of Y chromosomes in North America and because of this caution should be taken when inferring prehistoric population events in North America using Y chromosome data alone. However, consistent with studies of other genetic systems, we are still able to identify close relationships among Y chromosomes in Athapaskans from the Subarctic and the Southwest, suggesting that a small number of proto‐Apachean migrants from the Subarctic founded the Southwest Athapaskan populations. Am J Phys Anthropol, 2008. © 2008 Wiley‐Liss, Inc.
Semiconductor Wires and Ribbons for High‐ Performance Flexible Electronics
Authors: Baca Alfred J. , Ahn Jong‐Hyun , Sun Yugang , Meitl Matthew A. , Menard Etienne , Kim Hoon‐Sik , Choi Won Mook , Kim Dae‐Hyeong , Huang Young , Rogers John A. 
Published: July 2008

AbstractThis article reviews the properties, fabrication and assembly of inorganic semiconductor materials that can be used as active building blocks to form high‐performance transistors and circuits for flexible and bendable large‐area electronics. Obtaining high performance on low temperature polymeric substrates represents a technical challenge for macroelectronics. Therefore, the fabrication of high quality inorganic materials in the form of wires, ribbons, membranes, sheets, and bars formed by bottom‐up and top‐down approaches, and the assembly strategies used to deposit these thin films onto plastic substrates will be emphasized. Substantial progress has been made in creating inorganic semiconducting materials that are stretchable and bendable, and the description of the mechanics of these form factors will be presented, including circuits in three‐dimensional layouts. Finally, future directions and promising areas of research will be described.
Synthesis and properties of novel polyimides from 3‐(4‐aminophenylthio)‐N‐aminophthalimide
Authors: Yan Jingling , Wang Zhen , Lv Changli , Yang Huili , Shang Zhenping , Gao Lianxun , Ding Mengxian 
Published: July 2008

AbstractA novel, asymmetric diamine, 3‐(4‐aminophenylthio)‐N‐aminophthalimide, was prepared from 3‐chloro‐N‐aminophthalimide and 4‐aminobenzenethiol. The structure of the diamine was determined via IR and 1H‐NMR spectroscopy and elemental analysis. A series of polyimides were synthesized from 3‐(4‐aminophenylthio)‐N‐aminophthalimide and aromatic dianhydrides by a conventional two‐step method in N,N‐dimethylacetamide and by a one‐step method in phenols. These polyimides showed good solubility in 1‐methyl‐2‐pyrrolidinone, m‐cresol, and p‐chlorophenol, except polyimide from pyromellitic dianhydride, which was only soluble in p‐chlorophenol. The 5% weight loss temperatures of these polyimides ranged from 460 to 498°C in air. Dynamic mechanical thermal analysis indicated that the glass‐transition temperatures of the polyimides were in the range 278–395°C. The tensile strengths at break, moduli, and elongations of these polyimides were 146–178 MPa, 1.95–2.58 GPa, and 9.1–13.3%, respectively. Compared with corresponding polyimides from 4,4′‐diamiodiphenyl ether, these polymers showed enhanced solubility and higher glass‐transition temperatures. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Synthesis and characterization of active ester‐functionalized fluorescent polymers: New materials for protein conjugation
Authors: Wu Zhaoqiang 
Published: July 2008

AbstractA novel fluorescent monomer, N‐acryloylamido‐ethyl‐2‐(1‐pyrene)‐butyrylamidophenylpropionyl amide, was synthesized and copolymerized with N‐vinylpyrrolidone and N‐acryloxysuccinimide to obtain a series of functional fluorescent terpolymers. Fourier transform infrared spectroscopy, 1H‐NMR spectroscopy, gel permeation chromatography, ultraviolet–visible spectroscopy, and fluorescence spectroscopy were used to characterize these polymers. The protein–polymer conjugation was examined by sodium dodecyl sulfate/polyacrylamide gel electrophoresis. The results indicate that conjugate formation between the terpolymers and protein resulted from the succinimidyl ester groups, which led to the formation of stable amido linkages with proteins. The results of the interactions with the COS‐7 cell demonstrate that these synthesized terpolymers could attach to the surfaces of cells and emit fluorescence. These terpolymers with succinimidyl ester groups and high luminescence could be used as new materials for protein conjugation. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Effects of the filler loading and aging time on the mechanical and electrical conductivity properties of carbon black filled natural rubber
Authors: Azura A. R. , Ghazali Suriati , Mariatti M. 
Published: July 2008

AbstractThe effects of the filler loading and aging time on the mechanical and electrical conductivity properties of natural rubber were investigated. In this work, carbon black (type N220) was used as a filler, and its loading was varied from 0 to 50 phr. The mechanical properties (e.g., the tensile strength and catastrophic tearing energy) increased with a filler loading up to a certain loading, and a decrease in the mechanical properties was observed with higher filler loadings. The tensile strength and catastrophic tearing energy of the aged samples decreased after 3 and 6 days of aging at 100°C. The results for the electrical conductivity properties of unaged samples showed a percolation threshold at 20 phr, and the values were consistent with further filler loadings. After aging, the percolation threshold was still maintained at 20 phr. The morphologies of unaged and aged samples were significantly different: holes were observed to occur in the aged samples. This might have been due to the movement of fillers when the materials were subjected to heat, and this subsequently influenced the mechanical properties of the natural rubber composites. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Degradation behavior of an ultraviolet and hygrothermally aged polyurethane elastomer: Fourier transform infrared and differential scanning calorimetry studies
Authors: Ludwick Adriane , Aglan Heshmat , Abdalla Mohamed O. , Calhoun Maria 
Published: July 2008

AbstractThe degradation behavior of an elastomeric polyurethane (PU) was investigated with accelerated ultraviolet (UV) and hygrothermal (HT) techniques. Samples were subjected to UV exposure and HT conditions for 3 or 5 months and were removed in 1‐month intervals from the test chambers. Their chemical structure was evaluated with Fourier transform infrared (FTIR) spectroscopy. The thermal transitions of the aged samples were evaluated with differential scanning calorimetry (DSC). Both FTIR and DSC results showed no evidence of significant structural damage to the HT‐aged PU throughout exposure. FTIR analysis of the UV‐aged samples showed a noticeable change in the chemical structure of the polymer after 1 month of UV exposure. The results from DSC correlated with the FTIR analysis of the UV‐aged samples. Spectroscopic and thermal analysis of the aging of the PU samples was correlated to mechanical analysis. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Synthesis and properties of poly[N‐(4‐n‐butoxybenzoyl)‐2‐ethynylpyridinium chloride]
Authors: Gal Yeong‐Soon , Jin Sung‐Ho , Park Jong‐Wook 
Published: July 2008

AbstractWe first synthesized a new ionic polyacetylene with benzoyl functional groups by the activation polymerization of 2‐ethynylpyridine with 4‐butoxybenzoyl chloride without any additional initiator or catalyst. The acetylenic triple bond of N‐benzoyl‐2‐ethynylpyridinium chloride, formed in the first quaternarization process, was also found to be susceptible to linear polymerization. The polymer structure was characterized by various instrumental methods to give the ideal conjugated polyene backbone structure with the designed N‐(4‐n‐butoxybenzoyl‐2‐ethynylpyridinium) substituent and chloride counterion. The photoluminescence spectrum showed two distinguished maximum values at 575 and 630 nm, corresponding to photon energies of 2.16 and 1.97 eV, respectively. The electrochemical properties of this ionic polyacetylene were also measured and are discussed. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Synthesis and characterization of novel, biodegradable, thermally stable chitin‐based polyurethane elastomers
Authors: Zia Khalid Mahmood , Barikani Mehdi , Bhatti Ijaz Ahmad , Zuber Mohammad , Bhatti Haq Nawaz 
Published: July 2008

AbstractBiodegradable polyurethane (PU) elastomers with potential for biomedical and industrial applications with tunable thermal properties were synthesized by the reaction of poly(ϵ‐caprolactone) and 4,4′‐diphenylmethane diisocyanate and extended with different mass ratios of chitin and 1,4‐butane diol (BDO). Their chemical structures were characterized with Fourier transform infrared, 1H‐NMR, and 13C‐NMR spectroscopy, and the thermal properties were determined by thermogravimetric analysis, differential scanning calorimetry, and dynamic mechanical thermal analysis techniques. The incorporation of chitin contents into the PU backbone caused improvements in the thermal stability and degradation rate. Optimum thermal properties and degradation profile were obtained from elastomers extended with chitin, whereas elastomers extended with BDO displayed the worst properties. The investigation of the structure–property relationships of the prepared elastomers showed that the main determining factors for the observed properties were the physical effective crosslink density, hydrogen bonding, thermal stability, and content of chitin in the PU backbone. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Properties and application of poly(methacrylic acid‐co‐dodecyl methacrylate‐cl‐N,N‐methylene bisacrylamide) hydrogel immobilized Bacillus cereus MTCC 8372 lipase for the synthesis of geranyl acetate
Authors: Verma Madan Lal , Kanwar Shamsher Singh 
Published: July 2008

AbstractA range of fatty acid esters is now being produced commercially with immobilized microbial lipases (glycerol ester hydrolases; EC) in nonaqueous solvents. In this study, a synthetic hydrogel was prepared by the copolymerization of methacrylic acid and dodecyl methacrylate in the presence of a crosslinker, N,N‐methylene bisacrylamide. A purified alkaline thermotolerant bacterial lipase from Bacillus cereus MTCC 8372 was immobilized on a poly(methacrylic acid‐co‐dodecyl methacrylate‐cl‐N,N‐methylene bisacrylamide) hydrogel by an adsorption method. The hydrogel showed a 95% binding efficiency for the lipase. The bound lipase was evaluated for its hydrolytic potential toward various p‐nitrophenyl acyl esters with various C chain lengths. The bound lipase showed optimal hydrolytic activity toward p‐nitrophenyl palmitate at a pH of 8.5 and a temperature of 55°C. The hydrolytic activity of the hydrogel‐bound lipase was enhanced by Hg2+, Fe3+, and NH ions at a concentration of 1 mM. The hydrogel‐bound lipase was used to synthesize geranyl acetate from geraniol and acetic acid in n‐heptane. The optimization of the reaction conditions, such as catalyst loading, effect of substrate concentration, solvent (n‐pentane, n‐hexane, n‐heptane, n‐octane, and n‐nonane), reaction time, temperature, molecular sieve (3 Å × 1.5 mm) and scale up (at 50‐mL level), was studied. The immobilized lipase (25 mg/mL) was used to perform an esterification in n‐alkane(s) that resulted in the synthesis of approximately 82.8 mM geranyl acetate at 55°C in n‐heptane under continuous shaking (160 rpm) after 15 h when geraniol and acetic acid were used in a ratio of 100 : 100 mM. The addition of a molecular sieve (3 Å × 1.5 mm) to the reaction system at a concentration of 40 mg/mL in reaction volume (2 mL) resulted in an increase in the conversion of reactants into geranyl acetate (90.0 mM). During the repetitive esterification under optimum conditions, the hydrogel‐bound lipase produced ester (37.0 mM) after the eighth cycle of reuse. When the reaction volume was scaled up to 50 mL, the ester synthesized was 58.7 mM under optimized conditions. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Optimized conditions for the grafting reaction of poly(methyl methacrylate) onto oil‐palm empty fruit bunch fibers
Authors: Bakar Aznizam Abu , Mat Nik Sulaiman Nik , Isnin Mohd Kamaruddin 
Published: July 2008

AbstractThis article describes the graft copolymerization of poly(methyl methacrylate) (PMMA) onto oil‐palm empty fruit bunches (OPEFBs) with a fiber length of less than 75 μm. The graft copolymerization was carried out under a nitrogen atmosphere by a free‐radical initiation technique in an aqueous medium. Hydrogen peroxide and ferrous ions were used as a redox initiator/cocatalyst system. The PMMA homopolymer that formed during the reaction was removed from the grafted copolymers by Soxhlet extraction. Determining the effects of the reaction period, reaction temperature, and monomer concentration on the grafting percentage was the main objective, and they were investigated systematically. The optimum reaction period, reaction temperature, monomer concentration, and initiator concentration were 60 min, 50°C, 47.15 × 10−3 mol, and 3.92 × 10−3 mol, respectively. The maximum percentage of grafting achieved under these optimum conditions was 173%. The presence of PMMA functional groups on OPEFB and the enormous reduction of the hydroxyl‐group absorption band in PMMA‐g‐OPEFB spectra provided evidence of the successful grafting reaction. The improvement of the thermal stability of PMMA‐g‐OPEFB also showed the optimal achievement of the grafting reaction of PMMA onto OPEFB. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Fracture behavior of thermoplastic polyolefin/clay nanocomposites
Authors: Tjong S. C. , Ruan Y. H. 
Published: July 2008

AbstractA thermoplastic polyolefin (TPO) containing 70 wt % styrene–ethylene–butadiene‐styrene‐g‐maleic anhydride and 30 wt % polypropylene and its nanocomposites reinforced with 0.3–1.5 wt % organoclay were prepared by melt mixing followed by injection molding. The mechanical and fracture behaviors of the TPO/clay nanocomposites were investigated. The essential work of fracture (EWF) approach was used to evaluate the tensile fracture behavior of the nanocomposites toughened with elastomer. Tensile tests showed that the stiffness and tensile strength of TPO was enhanced by the addition of low loading levels of organically modified montmorillonite. EWF measurements revealed that the fracture toughness of the TPO/clay nanocomposites increased with increasing clay content. The organoclay toughened the TPO matrix of the nanocomposites effectively. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Preparation and self‐assembly behavior of thermosensitive polymeric micelles comprising poly(styrene‐b‐N,N‐diethylacrylamide)
Authors: Bian Fengling , Xiang Miao , Yu Wei , Liu Mingzhu 
Published: July 2008

AbstractThe amphiphilic block copolymer poly(styrene‐b‐N,N‐diethylacrylamide) (PSt‐b‐PDEA) was synthesized by reversible addition‐fragmentation chain transfer (RAFT) polymerization of styrene and N,N‐diethylacrylamide. The results of 1H‐NMR and GPC analysis showed that the synthesized PSt‐b‐PDEA copolymer had controlled molecular weight and narrow polydispersity. Polymeric micelles having a unimodal size distribution with an average diameter of 40 ± 0.5 nm were obtained from purified PSt‐b‐PDEA using a dialysis method. And the results showed that the clearance of homopolymer in copolymer is the key to prepare the unimodal distribution core‐shell nanomicelles. The micelles were thermodynamically stable in aqueous media with a low critical micelle concentration value (0.1 mg L−1). The aqueous micelles solution underwent a reversible dispersion/aggregation transition at around 29°C, which corresponds to the lower critical solution temperature (LCST) of the outer shell PDEA block chains. It is hoped that with their unique characteristics, those thermoresponsive polymeric micelles would found application in drug delivery. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Effect of branched PP content on the physical properties and cell growth during foaming of TPOs
Authors: McCallum Tara J. , Kontopoulou Marianna , Park Chul B. , Wong Anson , Kim Seong G. 
Published: July 2008

AbstractLinear/branched PP blends at various ratios were used as the matrix for thermoplastic olefin (TPO) compounds, containing an ethylene–octene copolymer dispersed phase. A detailed investigation of the physical properties of these blends revealed that addition of branched PP (BPP) resulted in improved stiffness and flexural properties. Given that the phase morphology of the blends and the interfacial tension between their components remained virtually unaffected, these improvements are attributed to the higher stiffness of the BPP‐containing matrices. Talc‐filled TPOs containing branched PPs exhibited further improvements in the stiffness and flexural properties. An investigation into the bubble growth process during foaming using a batch foaming simulation system revealed that the presence of BPP resulted in a slight delay in cell nucleation, whereas the rate of bubble growth was not significantly altered. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Influence of treatment duration on hydrophobic recovery of plasma‐treated ultrahigh modulus polyethylene fiber surfaces
Authors: Ren Yu , Hong Yuyan , Sun Jie , Qiu Yiping 
Published: July 2008

AbstractOne of the major disadvantages of ultrahigh modulus polyethylene (UHMPE) fibers is their low surface energy which makes them difficult to adhere to most of the resins used in composites. Therefore, UHMPE fibers are often treated with plasmas to improve their surface properties. However, aging of plasma treatment effect is a major concern for plasma‐treated fibers. In this study, UHMPE fibers were treated for 30, 60, 90, and 120 s with Ar/O2 plasma on a dielectric barrier discharge device. The change of the surface properties and adhesion characteristics of the fibers were investigated immediately after and 30 days after the plasma treatments using X‐ray photoelectron spectroscopy, contact angle measurement, scanning electron microscopy, and micro‐bond tests. Results show that aging of the plasma treatment effect was suppressed by increasing the plasma treatment duration. The interfacial shear strengths were increased from 4 MPa to 5.9, 7.8, 9.2, and 7.6 MPa for the 30, 60, 90, and 120 s treatment groups, respectively. After 30 days' aging, the IFSS for the 30, 60, 90, and 120 s treatment groups lowered 24, 22, 10, and 9%, respectively. Increasing the plasma treatment time will increase the thickness and saturation degree of the oxidized layer on the polymer surfaces, which might hinder the migration of the hydrophobic polar functional groups from the surface to the bulk of the polymer after the plasma treatment. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Proton‐conducting polyhedral oligosilsesquioxane nanoadditives for sulfonated polyphenylsulfone hydrogen fuel cell proton exchange membranes
Authors: Hartmann‐Thompson Claire , Merrington Adrian , Carver Peter I. , Keeley Douglas L. , Rousseau Joseph L. , Hucul Dennis , Bruza Kenneth J. , Thomas Lowell S. , Keinath Steven E. , Nowak Robert M. , Katona Denise M. , Santurri Pasco R. 
Published: July 2008

AbstractThree novel polyhedral oligosilsesquioxane (POSS) nanofillers functionalized with proton‐conducting sulfonic acid groups, mixed sulfonic acid and alkyl groups, and phosphonic acid groups were synthesized, characterized by IR, 1H and 13C NMR, and MALDI‐TOF MS, and formulated into sulfonated polyphenylsulfone (S‐PPSU) carrier polymers. High quality films were cast from 1‐methyl‐2‐pyrrolidinone (NMP), and through‐plane and in‐plane proton conductivity, mechanical properties, water uptake, dimensional stability, and leaching behavior were measured to assess their suitability for use as hydrogen fuel cell proton exchange membranes. Various nanofiller loadings and S‐PPSU sulfonation levels were studied. The morphologies of the composite membranes were determined by TEM and SEM X‐ray mapping. When compared with Nafion®, the POSS‐S‐PPSU composite membranes exhibited comparable proton conductivity in combination with superior dimensional stability, heat resistance, and mechanical strength. When compared with control S‐PPSU membranes, the composite POSS‐S‐PPSU membranes exhibited superior conductivity, comparable dimensional stability, and slightly decreased mechanical strength. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008