bluuebunny/crossref_metadata_2025_split huggingface dataset:
Integration, phylogeny, and the hominid cranial base
Authors: Strait David S. 
Published: August 2002

AbstractBasicranial features were examined in catarrhine primates and early hominids in order to demonstrate how information about morphological integration can be incorporated into phylogenetic analysis. Hypotheses purporting to explain the functional and structural relationships of basicranial characters were tested using factor analysis. Characters found to be functionally or structurally related to each other were then further examined in order to determine whether there was evidence that they were phylogenetically independent. If phylogenetic independence could not be demonstrated, then the characters were presumed to be integrated and were grouped into a complex. That complex was then treated as if it were a single character for the purposes of cladistic analysis.Factor analysis revealed that five basicranial features may be structurally related to relative brain size in hominoids. Depending on how one defines phylogenetic independence, as few as two, or as many as all of those characters might be morphologically integrated. A cladistic analysis of early hominids based on basicranial features revealed that the use of integrated complexes had a substantial effect on the phylogenetic position of Australopithecus africanus, a species whose relationships are poorly resolved. Moreover, the use of complexes also had an effect on reanalyses of certain published cladistic data sets, implying that those studies might have been biased by patterns of basicranial integration. These results demonstrate that patterns of morphological integration need to be considered carefully in all morphology‐based cladistic analyses, regardless of taxon or anatomical focus. However, an important caveat is that the functional and structural hypotheses tested here predicted much higher degrees of integration than were observed. This result warns strongly that hypotheses of integration must be tested before they can be adequately employed in phylogenetic analysis. The uncritical acceptance of an untested hypothesis of integration is likely to be as disruptive to a cladistic analysis as when integration is ignored. Am J Phys Anthropol 114:273–297, 2001. © 2001 Wiley‐Liss, Inc.
Geographic variation in tool use on Neesia fruits in orangutans
Authors: Van Schaik Carel P. , Knott Cheryl D. 
Published: August 2002

AbstractGeographic variation in the presence of skilled behavior may reflect geographic variation in genetic predispositions or ecological conditions (accompanied by reliable expression during development), or it may reflect the vagaries of invention and the appropriate social conditions for persistence. In this study, we compare the feeding techniques and tool‐using skills used by orangutans to extract the nutritious seeds from Neesia fruits between Suaq Balimbing on Sumatra and Gunung Palung on Borneo, and map the distribution of Neesia tool use in Sumatran swamps. We show that neither genetics nor ecology is sufficient to explain the distribution of this tool use, confirming earlier findings on chimpanzees. We conclude that the ability to learn to use tools determines the geographic distribution. It is impossible to distinguish between the history of invention and the conditions for social transmission as the causal factors, but the high density and the social tolerance at Suaq Balimbing create propitious conditions for the maintenance of the skill as a tradition once it has been invented. High orangutan densities in the other Sumatran coastal swamps with Neesia tool use support the conclusion that suitable transmission conditions are the critical factor to explain the geographic distribution of skills such as feeding tool use. Am J Phys Anthropol 114:331–342, 2001. © 2001 Wiley‐Liss, Inc.
Reorganization of somatic sensory function in the human thalamus after stroke
Authors: Ohara Shinji , Lenz Frederick A. 
Published: August 2002

AbstractA patient with a thalamic stroke underwent a microelectrode‐guided stereotactic thalamic exploration during surgery for control of tremor. The results of somatic sensory mapping in this patient were compared with explorations carried out during stereotactic surgery for the control of essential tremor (70 patients). There was evidence both of somatotopic reorganization and of anatomic reorganization of the representation of deep structures in the principal somatic sensory nucleus of the thalamus and the nuclei located anterior to it. This case demonstrates that thalamic reorganization can occur after a thalamic stroke and may play a role in recovery from such a stroke.
Metabolites of arsenobetaine in rats: does decomposition of arsenobetaine occur in mammals?
Authors: Yoshida Kaoru , Kuroda Koichi , Inoue Yoshinori , Chen Hua , Wanibuchi Hideki , Fukushima Shoji , Endo Ginji 
Published: August 2002

AbstractBiotransformation following oral administration of arsenobetaine (AsBe), the major arsenic compound in marine animals, was studied in rats. Male F344/DuCrj rats were administered a single dose of AsBe (20 mg As kg−1) orally. Urine was collected at 0, 2, 4, 6, 8, 10, 12, 24, 48, 72, and 96 h after administration by forced urination. Arsenic metabolites in urine were analyzed by ion chromatography with inductively coupled plasma mass spectrometry. Urinary elimination of AsBe, trimethylarsine oxide (TMAO), dimethylarsinic acid (DMA), methylarsonic acid (MMA), tetramethylarsonium (TeMA), an unidentified arsenic metabolite, arsenate, and arsenite was determined at various time points after administration. Unmetabolized AsBe was the most common form. Most elimination of unchanged AsBe occurred within 48 h, with peak elimination between 0 and 2 h. A small portion of administered AsBe was eliminated as TMAO and TeMA, with peak elimination between 0 and 2 h. Elimination of the unidentified metabolite, MMA, DMA, and inorganic arsenic occurred later and to a slight extent. A delay in elimination of the unidentified compound, MMA, DMA, and inorganic arsenic compared with that of TMAO suggests that the former compounds may be formed from TMAO. Degradation of AsBe by an intestinal bacterium, Escherichia coli, did not occur in rats. These results suggest that TMAO may be formed from AsBe, and that TMAO may subsequently be converted to the unidentified compound and demethylated arsenic compounds. Copyright ­© 2001 John Wiley & Sons, Ltd.
High‐density polyethylene/carbon black conductive composites. II. Effect of electron beam irradiation on relationship between resistivity–temperature behavior and volume expansion
Authors: Zhang Jian‐Feng , Zheng Qiang , Yang Yi‐Quan , Yi Xiao‐Su 
Published: August 2002

AbstractA study on the contribution of thermal volume expansion to electrical properties is carried out for high‐density polyethylene (HDPE)/carbon black (CB) composites irradiated by an electron beam. The results show that the volume expansion obviously generates the positive temperature coefficient (PTC) characteristic of resistivity for unirradiated HDPE/CB composites, but the contribution of volume expansion is decreased for crosslinked HDPE in the composites by electron beam irradiation. A higher degree of crosslinking produced by irradiation in the molten state limits the movability of HDPE chains and CB particles so effectively that it decreases the PTC intensity, which is compared with that irradiated at room temperature. It is suggested that the differences in the resistivity–temperature behavior are not explained satisfactorily on only the basis of the thermal volume expansion, and the decreased movability of HDPE chains and CB particles are believed to be the most fatal factors in lowering the PTC effect. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 3117–3122, 2002; DOI 10.1002/app.10050
Drug‐releasing behavior of MPEG/PLA block copolymer micelles and solid particles controlled by component block length
Authors: Kyu Sung , Dukjoon Choi , Kim  
Published: August 2002

AbstractThree series of poly(ethylene glycol)methyl ether (MPEG)/poly(lactic acid) (PLA) block copolymer systems, composed of MPEG in the molecular weights of 2000, 5000, and 750 g/gmol, respectively, and PLA in different molecular weights were synthesized. The chemical structure and physical properties were investigated using FTIR, NMR, DSC, TGA, and GPC. Different crystallization and melting transition behavior were observed according to the variation of the component block length. Either nano‐sized micelles or solid particles were formed in water, depending on the component block length and its ratio. The mean diameter of spherical drug carriers was controlled by the preparation conditions and was characterized using DLS and SEM. Indomethacin was loaded into nano‐sized spherical polymer carriers. The releasing rates were significantly affected by not only the sizes but also by the physical state of the drug carriers in the media, resulting from the difference in the component block length and the molecular entanglement of the PLA cores. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 435–445, 2002
Use of rice husk ash as filler in natural rubber vulcanizates: In comparison with other commercial fillers
Authors: Sae‐Oui P. , Rakdee C. , Thanmathorn P. 
Published: August 2002

AbstractRice husk ash is mainly composed of silica and carbon black remaining from incomplete combustion. Both silica and carbon black have long been recognized as the main reinforcing fillers used in the rubber industry to enhance certain properties of rubber vulcanizates, such as modulus and tensile strength. In this study, two grades of rice husk ash (low‐ and high‐carbon contents) were used as filler in natural rubber. Comparison was made of the reinforcing effect between rice husk ashes and other commercial fillers such as talcum, china clay, calcium carbonate, silica, and carbon black. Fourier transform infrared spectroscopy (FTIR) analysis was employed to study the presence of functional groups on the ash surface. The effect of silane coupling agent, bis(3‐triethoxysilylpropyl)tetrasulfane (Si‐69), on the properties of ash‐filled vulcanizates was also investigated. It was found that both grades of rice husk ash provide inferior mechanical properties (tensile strength, modulus, hardness, abrasion resistance, and tear strength) in comparison with reinforcing fillers such as silica and carbon black. However, the mechanical properties of the vulcanizates filled with rice husk ash are comparable to those filled with inert fillers. The addition of silane‐coupling agent has little effect on the properties of the ash‐filled vulcanizates. This is simply due to the lack of silanol groups on the ash surface. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2485–2493, 2002
Effect of degumming on the tensile properties of silkworm (Bombyx mori) silk fiber
Authors: Pérez‐Rigueiro J. , Elices M. , Llorca J. , Viney C. 
Published: August 2002

AbstractForcibly reeled silkworm (Bombyx mori) silk was used to study how exposure to a degumming treatment (boiling in distilled water for 30 min) affects tensile properties. Because forcibly reeled and naturally spun fibers exhibit comparable mechanical behavior, the results can be generalized to material obtained conventionally from cocoons. The effects of degumming include: a decrease in the initial elastic modulus, a decrease in the stress at the proportional limit (yield strength), a change in the qualitative shape of force‐displacement curves, and significant qualitative and quantitative variability in force‐displacement data from samples subjected to nominally identical degumming histories. Immersion in water at room temperature or heating in air at 100°C for 30 min are both qualitatively equivalent to a 30‐min degumming treatment in boiling water, in terms of the effect on silk tensile properties. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1431–1437, 2002; DOI 10.1002/app.10366
Synthesis and evaluation of sucrose‐containing polymeric hydrogels for oral drug delivery
Authors: Shantha K. L. , Harding D. R. K. 
Published: August 2002

AbstractBiodegradable and biocompatible copolymeric hydrogels based on sucrose acrylate, N‐vinyl‐2‐pyrrolidinone, and acrylic acid were designed and synthesized. Because of the growing importance of sugar‐based hydrogels as drug delivery systems, these new pH‐responsive sucrose‐containing copolymeric hydrogels were investigated for oral drug delivery. The sucrose acrylate monomer was synthesized and characterized. The copolymeric hydrogel was synthesized by free‐radical polymerization. Azobisisobutyronitrile (AIBN) was the free‐radical initiator employed and bismethyleneacrylamide (BIS) was the crosslinking agent used for hydrogel preparations. Homopolymeric vinyl pyrrolidone hydrogels were also prepared by the same technique. The hydrogels were characterized by differential scanning calorimetry, thermogravimetric analysis, and scanning electron microscopy. Equilibrium swelling studies were carried out in enzyme‐free simulated gastric and intestinal fluids (SGF and SIF, respectively). These results indicate the pH‐responsive nature of the hydrogels. The gels swelled more in SIF than in SGF. A model drug, propranolol hydrochloride (PPH), was entrapped in these gels and the in vitro release profiles were established separately in both enzyme‐free SGF and enzyme‐free SIF. The drug release was found to be faster in SIF. About 93 and 99% of the entrapped drug was released over a period of 24 h in SGF and SIF, respectively. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2597–2604, 2002
Polyimide nanocomposite with a hexadecylamine clay: Synthesis and characterization
Authors: Chang Jin‐Hae , Park Dae‐Keun , Ihn Kyo Jin 
Published: August 2002

AbstractA poly(amic acid) was prepared by the reaction of 3,3′‐dihydroxybenzidine and pyromellitic dianhydride in N,N‐dimethylacetamide. Hexadecylamine was used as an organophilic alkylamine in organoclay. Cast films were obtained from blend solutions of the precursor polymer and the organoclay. The cast film was heat treated at different temperatures to create polyimide (PI) hybrid films. We set out to clarify the intercalation of PI chains to hexadecylamine–montmorillonite (C16–MMT) and to improve thermal and tensile properties and the gas barrier. It was found that the addition of only a small amount of organoclay was enough to improve both the thermal and the mechanical properties of PIs. Maximum enhancement in the ultimate tensile strength for PI hybrids was observed for the blends containing 4% C16–MMT. The initial modulus monotonically increased with further increases in C16–MMT content. Water vapor permeability was decreased with increasing clay loading from 1 to 8 wt %. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2294–2301, 2002
Hemodialysis membrane prepared from cellulose/N‐methylmorpholine‐N‐oxide solution. I. Effect of membrane preparation conditions on its permeation characteristics
Authors: Abe Yoshihiko , Mochizuki Akira 
Published: August 2002

AbstractFlat hemodialysis membranes were prepared from cellulose/N‐methylmorpholine‐N‐oxide (NMMO) solutions (dope) with different cellulose concentrations (6–8 wt %) by using a phase‐inversion method. The coagulant used was NMMO aqueous solution, of which the NMMO concentration and its temperature were varied in the range of 0 to 50 wt % and 5 to 60°C, respectively. The effects of these preparation conditions on the permeation characteristics, the ultrafiltration rate (UFR) of pure water, and sieving coefficient (SC) of dextran, were investigated. The decrease in cellulose concentration of the dope and the increases in both temperature and NMMO concentration of the coagulant gave a membrane with high UFR. Concerning the SC, the increase of the cellulose concentration and the decreases in both temperature and NMMO concentration gave a good result. Consequently, the membrane having the preferable UFR and SC as a hemodialysis membrane was obtained when the 8 wt % cellulose dope was coagulated in water at 5°C. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2302–2307, 2002
Conduction mechanism in H‐type polysiloxane‐polypyrrole block copolymers
Authors: Bozkurt A. , Parlak M. , Erçelebi Ç. , Toppare L. 
Published: August 2002

AbstractConducting polymers of polysiloxane‐polypyrrole were synthesized by electropolymerization of the pyrrole monomer through pyrrole moieties in N‐pyrrole‐terminated polysiloxanes. Sodium paratoluene sulfonate was used as the electrolyte. Scanning electron microscopy (SEM) was used to determine the surface morphology of the films. The room‐temperature conductivity values of the films were found to be in the range of 1.9–4.4 × 10−4 (Ω cm)−1, depending on the supporting electrolyte concentration. The temperature dependence of the dc conductivities of the copolymers having different dopant concentrations was investigated within the temperature range of 100–320 K. The evaluated parameters showed that the electrical transport is dominated by variable range hopping. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 52–56, 2002
Simultaneous determination of molecular weight and crystallinity of recycled HDPE by infrared spectroscopy and multivariate calibration
Authors: Camacho Walker , Karlsson Sigbritt 
Published: August 2002

AbstractAn attempt of correlating molecular weight (Mn) of recycled high‐density polyethylene (HDPE) as measured by size‐exclusion chromatography (SEC) with diffuse reflectance near and mid‐infrared spectroscopy (NIR/MIR) was made by means of multivariate calibration. The spectral data obtained was also used to extract information about the degree of crystallinity of the recycled resin. Differential scanning calorimetry (DSC) was used as the reference method. Partial least‐squares (PLS) calibration was performed on the MIR and NIR spectral data for prediction of Mn. Four PC factors described fully the PLS models. The root‐mean‐square error of prediction (RMSEP) obtained with MIR data was 360, whereas a RMSEP of 470 was achieved when calibration was carried out on the diffuse reflectance NIR data. A PLS calibration for prediction of degree of crystallinity was performed on the NIR data in the 1100–1900‐nm region, but the ability of prediction of this model was poor. However a PLS calibration in the region 2000–2500 nm yield better results. Four PC factors explained the most of the variance in the spectra and the RMSEP was 0.4 wt %. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 321–327, 2002
Grafting of selected presynthesized macromonomers onto various dispersions of silica particles
Authors: Sartore Luciana , Penco Maurizio , Bignotti Fabio , Peroni Isabella , Gil Maria Helena , Ramos M. Andrade , D'Amore Alberto 
Published: August 2002

AbstractA new process was developed which enables one to obtain surface‐modified silica with a high heavy metal ion complexing ability. The synthetic approach is based on grafting of vinyl‐terminated macromonomers onto silica via covalent bonding. A proper selection of the macromonomer structure, molecular weight, and molecular weight distribution allows materials to be obtained with a range of desirable properties. The process has been tested on various dispersions (ranging from 35 and 200 μm) of silica particles and two structurally related macromonomers. Native silica and the resulting mixed organic–inorganic products were fully characterized by IR spectroscopy, SEM, yield of grafting (elemental analysis and calcination), density (helium pycnometry), specific surface area (BET method), and pore size (gas adsorption and mercury porosimetry) measurements. It was found that the corresponding polymers are effectively grafted onto the surface; the density, surface area, and pore size of the silica particles decrease with polymer grafting. Preliminary results on metal‐ion uptake indicate that polymer‐grafted silica exhibits an excellent complexing ability. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1287–1296, 2002
Synthesis of polyetherols from melamine and ethylene carbonate
Authors: Kucharski Mieczysław , Kijowska Dorota 
Published: August 2002

AbstractAttempts to synthesize s‐triazine ring containing polyetherols from melamine and ethylene carbonate are described. The conditions of synthesis providing optimal yields of the polyetherols were 165°C, melamine to ethylene carbonate molar ratio 1 : 9 to 1 : 18, and 4 g of potassium carbonate or diazabicyclo[2.2.2]octane catalyst per mole of melamine. The structure of the products was established by 1H‐NMR and IR spectroscopy. The kind and amount of side products [mostly poly(ethylene glycols)] was determined by GLC. The polyetherols have been found useful in the synthesis of polyurethanes of improved thermal stability. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1776–1784, 2001
Erasure below glass‐transition temperature of effect of isothermal physical aging in fully cured epoxy/amine thermosetting system
Authors: Lee Jong Keun , Hwang Jae Young , Gillham J. K. 
Published: August 2002

AbstractThe erasure below the glass‐transition temperature (Tg) of the effect of isothermal physical aging (at aging temperature Ta) in a fully cured epoxy/amine thermosetting system is investigated using the torsional braid analysis (TBA) dynamic mechanical analysis technique and the differential scanning calorimetry (DSC) technique. From the TBA temperature scans, the intensity of the localized perturbation of the moduli in the vicinity of the Ta (90°C), due to isothermal physical aging, is decreased by heating to below the Tg (Tg∞ = 177°C), indicating that the physical aging effect can be eliminated by heating to below the Tg. The isothermal aging effect in the vicinity of the Ta is almost completely eliminated by heating to 50°C above the Ta (i.e., 140°C); however, a competing aging effect occurs above Ta at higher temperatures during the heating. Erasure below Tg of the isothermal physical aging effect is inferred from DSC experiments from the diminished relaxation enthalpy in the vicinity of the Tg, which is measured from the difference in areas between the aged (Ta = 150°C) and deaged thermograms. A comparison of the TBA and DSC results is made. Implications on the heterogeneous nature of the amorphous glassy state of polymers are discussed. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 396–404, 2001
Separation and extraction of some heavy and toxic metal ions from their wastes by grafted membranes
Authors: Hegazy El‐Sayed A. , Kamal H. , Khalifa N. A. , Mahmoud Gh. A. 
Published: August 2002

AbstractPreparation and characterization of a series of ion‐exchange membranes for the purpose of separation and extraction of some heavy and toxic metal ions from their wastes were studied. Such ion‐exchange membranes were prepared by γ‐radiation grafting of acrylonitrile (AN) and vinyl acetate (VAc) in a binary monomer mixture onto low‐density polyethylene (LDPE) using the direct technique of grafting. The reaction conditions at which the grafting process proceeds successfully were determined. Many modification treatments were attempted for the prepared membranes to improve their ion‐exchange properties. The possibility of their practical use in waste‐water treatment to remove some heavy and toxic metal ions such as Pb2+, Cd 2+, Cu2+, Fe3+, Sr2+, and Li+ were investigated. These grafted membranes showed great promise for possible use in the field of extraction and removal of some heavy and toxic metals from their wastes. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 849–860, 2001
Generalization of polymer/organic solvent interaction processes by means of linear polyparameter equations. I. Swelling of polyethylene
Authors: Makitra R. , Pyrih Y. , Sagladko E. , Turovskiy A. , Zaikov G. 
Published: August 2002

AbstractA solvent's molar volume is the factor that determines its ability to penetrate into a polymer structure. However, the available data for polyethylene swelling in organic solvents may be quantitatively linked with their physicochemical properties only by use of polyparameter equations, which take into account not only the molar volume of solvents but also their ability for specific and nonspecific solvation. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 3133–3140, 2001