bluuebunny/crossref_metadata_2025_split huggingface dataset:
Child growth as a measure of livelihood security: The case of the Gwembe Tonga
Authors: Crooks Deborah L. , Cliggett Lisa , Cole Steven M. 
Published: July 2007

AbstractThis article outlines an approach to the study of child growth and development in adverse environments that utilizes growth to measure the success of the human/environment interaction. This type of biocultural, human adaptability perspective focuses on within group variation to gain an understanding of the differential ability of households to negotiate opportunities and constraints in the ecological/social/cultural environment. As an example, we report preliminary findings of on‐going research in a migrant Gwembe Tonga community in Zambia. Our analysis indicates that average height‐for‐age and weight‐for‐heightz‐scores of school children are below international references, representing compromised community well‐being in context of new and shifting environments. We report variation in average household child height‐for‐agez‐scores that is linked to differential livelihood strategies in the community. We conclude that in the context of shared circumstances that focus risk for poor health on this community as a whole, the ability of households to adapt to their circumstances varies as evidenced by differential growth outcomes. Am. J. Hum. Biol., 2007. © 2007 Wiley‐Liss, Inc.
Properties and behavior of CTBN‐modified epoxy with IPN structure
Authors: Hsu Ying‐Gev , Liang Chin‐Wei 
Published: July 2007

AbstractCTBN‐modified epoxy resins (CMEs) with an interpenetrating‐network (IPN) structure and a nanometer‐sized morphology were prepared. Two systems of CMEs, called CNE/DDS/I‐CTBN‐B and CNE/DDS/I‐CTBN‐D, with IPN structures, were synthesized by heat‐curing a homogeneous resin, CNE/DDS/CTBN/2‐MI, obtained by mixing a carboxyl‐terminated butadiene–acrylonitrile liquid rubber (CTBN) with a solution of polyglycidyl ether of o‐cresol‐formaldehyde novolac (CNE), 4,4′‐diamino diphenyl sulfone (DDS), and 2‐methyl imidazole (2‐MI), in the presence of benzoyl peroxide and dicumyl peroxide, respectively. The IPN morphologies of the two systems of CMEs were identified by small‐angle X‐ray scattering by measuring the value of the specific interfacial surface area Ssp between the cured CNE/DDS matrix and the vulcanized CTBN. Properties such as fracture toughness, internal stress, and thermal and dynamic mechanical properties of these IPN‐structured CMEs were studied in detail, and were compared with those of a conventional CME, CNE/DDS/CTBN, obtained by dispersing CTBN particles in a crosslinked CNE/DDS matrix. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Retention volumes of organic substances on ester phases
Authors: Bazylyak L. I. , Rohovyk V. I. , Makitra R. G. , Palchykova E. A. , Zaikov G. E. 
Published: July 2007

AbstractReliable methods of agreement does not exist between the chromatographic retention volumes of substances and their physicochemical properties. That is why it is impossible to predict these characteristics for unstudied substances. Well‐known works in this field have either qualitative character or give the results suitable only for homologous series. That is why it was very interesting to consider the available arrays of experimental data of gas‐liquid chromatography by means of Koppel‐Palm multi‐parameter equations. The individual characteristics of this equation are determined experimentally. The final multi‐parameter equation proposed by us was adequate for generalizing the retention‐time data for the polyester phase of substances with different structures and also for calculating this value for other (unstudied) substances on the basis their physicochemical characteristics. The generalizing equations permit us to draw conclusions about the nature of the processes taking place during the adsorption‐desorption of the substances in the stationary phase. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Matrimid polyimide membranes for the separation of carbon dioxide from methane
Authors: Sridhar S. , Veerapur R. S. , Patil M. B. , Gudasi K. B. , Aminabhavi T. M. 
Published: July 2007

AbstractThree types of polyimide membranes viz., Matrimid, Kapton and P84, were prepared by solution casting and solvent evaporation method to study the permeation of CO2 and CH4 gases. Barrier properties were investigated as a function of feed pressure for pure gases and feed composition for the binary mixtures of CO2 and CH4. Kapton polyimide, prepared by imidization of polyamic acid, showed an increase in permeability, but reduction in selectivity, due to the occurrence of plasticization at higher feed CO2 concentrations. Matrimid was found to exhibit the highest permeability and was studied in greater detail, due to the feasibility in its scale‐up into a hollow fiber modular configuration for commercial application. Matrimid was characterized by Fourier transform infrared (FTIR) spectroscopy and X‐ray diffractometry (XRD) to assess the intermolecular interactions and to understand the separation profiles. The effect of feed flow was evaluated by studying the permeation behavior of flat sheet membrane in dead‐end operation mode with the hollow fiber module operated in crossflow feed mode. For pure gases, Matrimid hollow fiber membrane exhibited a CO2 permeability of 12.7 Barrers with a CO2/CH4 selectivity of 40 at the feed pressure of 20 bar. At the same pressure, for binary mixture feed of 5 mol % CO2 in methane, the module gave a permeability of 7.4 Barrers with a selectivity of 21. The total binary mixture permeability was determined at the feed CO2 concentrations varying from 0 to 20 mol % to demonstrate the preferential sorption of CO2 in Matrimid membrane. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Absorbency and adsorption of poly(acrylic acid‐co‐acrylamide) hydrogel
Authors: Xie Jianjun , Liu Xinrong , Liang Jifu 
Published: July 2007

AbstractPoly(acrylic acid‐co‐acrylamide) (PAAAM) hydrogels have been prepared from partly neutralized acrylic acid (AA) and acrylamide (AM) by solution polymerization, and their absorbency and adsorption in both CuCl2 and FeCl3 solutions have been investigated. PAAAM hydrogels and their complexes with Cu2+ or Fe3+ have been characterized by FTIR. The absorbency of PAAAM in both CuCl2 and FeCl3 solutions increases initially and then decreases as the absorbing time increases. The adsorption of PAAAM in both CuCl2 and FeCl3 solutions can be described by the pseudo‐second order chemisorption kinetics proposed by Ho and McKay, and the equilibrium uptake of Cu2+ on PAAAM can well be fit with the Langmuir adsorption isotherm. However, the equilibrium uptake of Fe3+ on PAAAM increases as the initial Fe3+ concentration increases for Fe3+ concentration smaller than 5.625 × 10−3 mol/L, and then decreases with Fe3+ concentration. The largest uptakes for Cu2+ and Fe3+ are 247 and 173 mg/g, respectively. The results also show that the uptake of Cu2+ and Fe3+ on PAAAM increases remarkably when pH of the solution is changed from 2.3 to 4.2 and from 1.0 and 2.1, respectively. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Surface dyeability of cotton and nylon fabrics coated with a novel porous silk fibroin/silica nanohybrid
Authors: Li Wenbin , Zou Lingli , Zhou Xingpin , Zhang Baohua , Wang Xiaqin , Chen Dajun 
Published: July 2007

AbstractA new and facile approach of surface dyeing was developed for cotton and nylon fabrics coated with a novel porous silk fibroin (SF)/silica (SiO2) nanohybrid. Actually, dyeing of the fabrics occurred in the very thin nanohybrid layers exclusively, while the main body of the fabrics remained intact on the whole. With the assistance of the large surface areas of the porous nanohybrid, dye uptake of the coated cotton fabrics dyed with Acid Red GSF or Disperse Cation Red SD‐GRL was enhanced substantially compared with that of the uncoated fabrics as a control. Moreover, dye uptake increased with the SF content in the hybrid, indicating that the SF moiety played a significant role for the surface dyeing process. Color fastness to water of both the dyestuffs was much higher for the coated cotton fabrics compared with that of the uncoated ones. Similar results were obtained for the nanohybrid coated nylon fabrics dyed with Disperse Cation Red SD‐GRL as those of the coated cotton fabrics. However, no increase was observed for dye uptake of the coated nylon fabrics dyed with Acid Red GSF owing to saturation of the dyestuff attached on the controlled uncoated nylon fabrics, which concealed the contribution of the nanohybrid layer. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Poly(lactic acid)/polystyrene bioblends characterized by thermogravimetric analysis, differential scanning calorimetry, and photoacoustic infrared spectroscopy
Authors: Mohamed Abdellatif , Gordon Sherald H. , Biresaw Girma 
Published: July 2007

AbstractBioblends are composites of at least one biodegradable polymer with nonbiodegradable polymer. Successful development of bioblends requires that the biodegradable polymers be compatible with other component polymers. Compatibility can be assessed by evaluating the intermolecular interactions between the component polymers. In this work, the interaction in binary bioblends comprising biodegradable poly(lactic acid) (PLA) and polystyrene (PS) was investigated using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and Fourier transform infrared photoacoustic spectroscopy (FTIR‐PAS). The TGA studies indicated that incorporation of PLA in PS resulted in thermal destabilization of PS. The DSC studies showed that some parameters favored partial miscibility of PS in PLA, while others favored immiscibility, such as the existence of two glass transitions. The FTIR‐PAS spectra revealed the presence of intermolecular n–π interactions between PLA and PS and indicated that the degree of interaction was dependent on the concentrations of the polymers in the bioblends. FTIR‐PAS results computed via differential spectral deconvolution were consistent with, and therefore support, the results of TGA and DSC analyses of PLA/PS bioblends. The degradation kinetics, used to determine the degradation mechanism, revealed a two‐ or three‐step mechanism. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Electrochemical deposition of polycarbazole thin films onto tin oxide coated glass: Physicochemical and optoelectronic characterizations
Authors: Yapi Abé S. , Bernède J. C. , Ugalde L. , Trégouët Y. , del Valle M. A. 
Published: July 2007

AbstractPolycarbazole (PCz) thin films have been synthesized by electrochemistry. The influence of the deposition technique, potentiostatic or potentiodynamic, on the properties of the PCz films has been studied using the deposition time and the potential maximum as parameters. The PCz films have been characterized by thermal analysis, X‐ray photoelectron spectroscopy (XPS), near ultra violet, visible and infra red absorption, photoluminescence (PL) measurements, scanning electron microscopy and microprobe analysis. Whatever the technique used, polymerized carbazole (Cz) films are deposited onto tin oxide coated glass. It is shown that potential maximum of 1400 mV or more induces some Cz nucleus destruction with NN bonds formation. It is also shown by different techniques such as XPS, visible and IR absorption, microanalysis, PL, that the oxido–reduction reaction is reversible. Moreover, after dedoping treatment, nearly pure PCz film can be obtained, which allows obtaining PCz depoped films with good PL properties. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
New functional bicomponent fibers with core/sheath‐configuration using poly(phenylene sulfide) and poly(ethylene terephthalate)
Authors: Houis Stéphanie , Schmid Manfred , Lübben Jörn 
Published: July 2007

AbstractBicomponent fibers using the high‐performance polymer poly(phenylene sulfide) (PPS) together with poly(ethylene terephthalate) (PET) were melt‐spun. Both possibilities of using PPS, either as core or as sheath material, were realized to provide special functionalities like improved thermobonding capability, flame retardancy, or chemical resistance. Parameters that guarantee stable processing of PPS and PET during coaxial extrusion with different core/sheath volume ratios were explored. Microscopic studies of the cross‐sections showed holes and cavities, which were formed at the interface between PPS and PET. Possible mechanisms for cavity formation were evaluated. Results of thermal and mechanical characterization by means of TGA, DSC, and tensile testing revealed a strong influence of the processing parameters, namely draw ratio and core/sheath volume ratio, on the crystallization and the tensile strength of the drawn fibers. By changing the core/sheath volume ratio from 2 to 0.5 in the PPS/PET fiber, the crystallinity of the PET‐component was switched from 10 to 50%, whereas the crystallinity of the PPS dropped from 68 to 7%. It was determined that bicomponent fibers can exceed the strength of monocomponent fibers up to 28%. The flammability and chemical resistance of the new developed fibers were characterized. In contrary to what was expected, the encasing of PET with PPS reduced the flame retardancy, though PPS has a higher flame resistance than PET. The chemical resistance of the PET core against hydrolysis was imparted by coextruding a PPS sheath. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
High‐temperature DSC study of polyacrylonitrile precursors during their conversion to carbon fibers
Authors: Wang Yan‐Xiang , Wang Cheng‐Guo , Wu Ji‐Wei , Jing Min 
Published: July 2007

AbstractThe evolution of structure, the changes of properties during the preoxidation, precarbonization, and carbonization of different polyacrylonitrile (PAN) precursors were firstly studied in detail by means of using high‐temperature differential scanning calorimetry (DSC) to characterize with continuous heating from 25 to 1400°C. It was essential to study the thermal behavior of PAN precursors so that proper temperature was determined. Three precursors with different composition, P1: acrylonitrile/itaconic acid (AN/IA) = 98/2 (wt/wt); P2: acrylonitrile/acrylamide (AN/AM) = 98/2 (wt/wt); P3: acrylonitrile/ammonium salt of itaconic acid (AN/AIA) = 98/2 (wt/wt) were, respectively, selected in this study. Comparative results of the DSC curves showed that the heating history influenced greatly the heat quantities released and exothermic position at low temperature of DSC curve, but influenced slightly at higher temperature. Aromatic index, carbon yield (Wc) and weight loss (η) can be calculated. After adjusting the temperature in preoxidation and precarbonization and carbonization technology depending on high‐temperature DSC, the high performance carbon fibers were obtained that tensile strength is 3.56–4.16 GPa, modulus is 235–243 GPa. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Polypropylene fibers containing dispersed clays having improved fire performance. I. Effect of nanoclays on processing parameters and fiber properties
Authors: Horrocks A. Richard , Kandola Baljinder K. , Smart Gillian , Zhang Sheng , Hull T. Richard 
Published: July 2007

AbstractWhile the present interest in the use of functionalized nanoclays as additives for improving tensile properties and fire performance in polypropylene thermoplastics has led to a considerable literature, little attention has been given to this polymer in fiber form. In this article, we report the conditions necessary for and the characteristics of filaments and tapes comprising dispersions of functionalized clay in polypropylene–clay prepared by melt compounding polypropylene in a twin screw extruder. A small fraction (1–3% w/w) of modified grafted polypropylene has also been included to improve dispersion of the clay. X‐ray diffraction of hot‐pressed films, coupled with transmission electron microscopic investigation has been used to assess the degree of dispersion of the clay. Clay dispersion at the nanolevel was observed by TEM, but intercalation was not evident from X‐ray study. Compounded samples were melt‐extruded into filaments using a single screw extruder and drawn prior to wind up. The physical properties of the clay‐containing polypropylene filaments showed that presence of dispersed clay increased filament modulus and was supportive of having achieved some degree of nanodispersion. Selected filament samples had sufficiently acceptable textile properties to enable their knitting into fabric samples. The burning behavior of fabric and film samples were observed by limiting oxygen index and cone calorimetry at 35 kW/m2 external heat flux. While the clay presence did not confer flame retardancy, it did change the burning character and encouraged some char formation. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Competitive removal of nickel (II), cobalt (II), and zinc (II) ions from aqueous solutions by starch‐graft‐acrylic acid copolymers
Authors: Güçlü Gamze , Güçlü Kubilay , Keleş Sibel 
Published: July 2007

AbstractGraft copolymerization of acrylic acid (AA) onto starch was carried out with ceric ammonium nitrate as initiator under nitrogen atmosphere. The grafting percentages (GP%) of starch‐graft‐acrylic acid (St‐g‐AA) copolymers were determined. The effect of GP% of St‐g‐AA copolymers on the competitive removal of Co2+, Ni2+, Zn2+ ions from aqueous solution was investigated at different pH (2, 4, 6). The concentrations of each ion in aqueous solution 5 mmol/L. Effects of various parameters such as treatment time, initial pH of the solution and grafting percentage of starch graft copolymers were investigated. Metal ion removal capacities of St‐g‐AA copolymers increased with GP% of the copolymers and pH. The results show that the removal of metal ions followed as given in the order Co2+ > Ni2+ > Zn2+. In this study, metal ion removal capacities were determined by atomic absorption spectrophotometer (AAS). © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Structure formation and characterization of PVDF hollow fiber membranes by melt‐spinning and stretching method
Authors: Du Chun‐Hui , Xu You‐Yi , Zhu Bao‐Ku 
Published: July 2007

AbstractMelt‐spinning and stretching (MS‐S) method was proposed for preparing poly(vinylidene fluoride) (PVDF) hollow fiber membranes with excellent mechanical properties. The morphology and properties of PVDF fibers and membranes were investigated by small angle X‐ray scattering (SAXS), differential scanning calorimeter (DSC), field emission scanning electron microscope, mercury porosimeter, and tensile experiment. SAXS results indicated that the stacked lamellar structure aligned normal to the fiber axis was separated and deformed when the fibers were strained, and the long period of the strained fibers increased accordingly. Factors affecting the membrane properties were mainly spin‐draw ratio, annealing temperature, time, and stretching rate. Experimental results showed that the average pore size, porosity, and N2 permeation of the membranes all increased with the increasing spin‐draw ratios and annealing temperatures. Annealing the nascent PVDF hollow fibers at 145°C for 12 h was suitable for attaining membranes with good performance. In addition, the amount and size of the micropores of the membrane increased obviously with stretching rate. Tensile experiment indicated PVDF hollow fiber membranes made by MS‐S process had excellent mechanical properties. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Abiotic impacts on spatial and temporal distribution of Corbicula fluminea (Müller, 1774) in the River Minho estuary, Portugal
Authors: Sousa Ronaldo , Rufino Marta , Gaspar Miguel , Antunes Carlos , Guilhermino Lúcia 
Published: July 2007

Abstract
The non‐indigenous species Corbicula fluminea (Müller, 1774) is one of the most invasive bivalves in freshwater ecosystems. This Asian clam was first reported in the River Minho estuary in 1989. After a short period of time, it became the major component of the local benthic fauna in terms of abundance and biomass.
In the autumn of 2004 and 2005, spatial and temporal variations in abundance, biomass and population structure of C. fluminea were investigated at 16 sites in the freshwater subtidal area of the River Minho estuary. Mean abundance and biomass per site ranged from 80 to 4185ind.m−2 and 8.5 to 465.9g AFDWm−2, respectively.
The environmental characterization of the area was performed through multivariate analysis, which revealed three distinct areas subjected to different abiotic conditions. C. fluminea population structure is well correlated with these three distinct areas.
The combination of several abiotic variables determining C. fluminea biomass distribution was evaluated through a stepwise multiple regression. This model showed that redox potential, nutrient concentrations, hardness, organic matter and sediment characteristics explained almost 60% of the variation in C. fluminea biomass in the freshwater subtidal area of the River Minho estuary (R2=59.3%, F[9,86]=13.9, p<0.001).
Improved ecological knowledge is essential for future C. fluminea management, in order to protect local habitats and biodiversity, and to reduce the economic impact of this non‐indigenous invasive species.
Copyright © 2007 John Wiley & Sons, Ltd.
An amalgamation of solid phase peptide synthesis and ribosomal peptide synthesis
Authors: Ottesen Jennifer J. , Bar‐Dagan Maya , Giovani Baldissera , Muir Tom W. 
Published: July 2007

AbstractExpressed protein ligation (EPL) is a protein semisynthesis technique that allows the site‐specific introduction of unnatural amino acids and biophysical probes into proteins. In the present study, we illustrate the utility of the approach through the generation of two semisynthetic proteins bearing spectroscopic probes. Dihydrofolate reductase containing a single 13C probe in an active site loop was generated through the ligation of a synthetic peptide‐α‐thioester to a recombinantly generated fragment containing an N‐terminal Cys. Similarly, c‐Crk‐II was assembled by the sequential ligation of three recombinant polypeptide building blocks, allowing the incorporation of 15N isotopes in the central domain of the protein. These examples showcase the scope of the protein ligation strategy for selective introduction of isotopic labels into proteins, and the protocols described will be of value to those interested in using EPL on other systems. © 2007 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 90:406–414, 2008.This article was originally published online as an acceptedpreprint. The “Published Online” date corresponds to the preprintversion. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Renaturation with simultaneous purification of rhG‐CSF from Escherichia coli by ion exchange chromatography
Authors: Wang Chaozhan , Wang Lili , Geng Xindu 
Published: July 2007

AbstractProtein refolding is a key step for the production of recombinant proteins, especially at large scales, and usually their yields are very low. Application of liquid chromatography to protein refolding is an exciting step forward for this field. In this work, recombinant human granulocyte colony‐stimulating factor (rhG‐CSF) expressed in Escherichia coli was renatured with simultaneous purification by ion exchange chromatography (IEC) with a Q Sepharose FF column. Several chromatographic parameters affecting the refolding yield of the denatured/reduced rhG‐CSF, such as the urea concentration, pH value, concentration and ratio of reduced/oxidized glutathione in the mobile phase, as well as the flow rate of the mobile phase, were investigated in detail and indicated that the urea concentration and the pH value were of great importance. At the optimal conditions, the renatured and purified rhG‐CSF was found to have a specific bioactivity of 3.0 × 108 IU/mg, a purity of 96%, and a mass recovery of 49%. Compared with the usual dilution method, the IEC method developed here is more effective for rhG‐CSF refolding in terms of specific bioactivity and mass recovery. Copyright © 2007 John Wiley & Sons, Ltd.