bluuebunny/crossref_metadata_2025_split huggingface dataset:
Brain size and the human cranial base: A prenatal perspective
Authors: Jeffery Nathan , Spoor Fred 
Published: September 2002

AbstractPivotally positioned as the interface between the neurocranium and the face, the cranial base has long been recognized as a key area to our understanding of the origins of modern human skull form. Compared with other primates, modern humans have more coronally orientated petrous bones and a higher degree of basicranial flexion, resulting in a deeper and wider posterior cranial fossa. It has been argued that this derived condition results from a phylogenetic increase in the size of the brain and its subcomponents (infra‐ and supratentorial volumes) relative to corresponding lengths of the cranial base (posterior and anterior, respectively). The purpose of this study was to test such evolutionary hypotheses in a prenatal ontogenetic context. We measured the degree of basicranial flexion, petrous reorientation, base lengths, and endocranial volumes from high‐resolution magnetic resonance images (hrMRI) of 46 human fetuses ranging from 10–29 weeks of gestation. Bivariate comparisons with age revealed a number of temporal trends during the period investigated, most notable of which were coronal rotation of the petrous bones and basicranial retroflexion (flattening). Importantly, the results reveal significant increases of relative endocranial sizes across the sample, and the hypotheses therefore predict correlated variations of cranial base flexion and petrous orientation in accordance with these increases. Statistical analyses did not yield results as predicted by the hypotheses. Thus, the propositions that base flexion and petrous reorientation are due to increases of relative endocranial sizes were not corroborated by the findings of this study, at least for the period investigated. Am J Phys Anthropol 118:324–340, 2002. © 2002 Wiley‐Liss, Inc.
Evolutionary significance of cranial variation in Asian Homo erectus
Authors: Antón Susan C. 
Published: September 2002

AbstractHomo erectus inhabited a wide geographic area of Asia, ranging from 40° north latitude in China to 8° south latitude in island Southeast Asia. Yet variation within Asian H. erectus and its relation to ecological and temporal parameters have been little studied. I synthesize the revised radiometric chronologies for hominid sites in Asia and their relation to new oxygen isotope curves (proxies for climatic fluctuations and landbridge connections). These data suggest substantial opportunities in the later Pleistocene for both regional isolation and gene flow between hominids in mainland and Southeast Asia. They also suggest that the most northerly located Chinese sites (Zhoukoudian and Nanjing) may have been occupied during sequential, interglacial periods. Probably reflecting these periods of isolation, nonmetric features and principal components analysis (PCA) of calvarial shape suggest regional differentiation between northern Asian and Southeast Asian H. erectus. The most recent Southeast Asian fossils (e.g., Ngandong) conform to the Southeast Asian pattern. Except perhaps in brain size, there is no evidence that the temporally intermediate Chinese fossils are intermediate in morphology between older and younger Indonesian fossils. In fact, northern Chinese calvaria are easier to exclude from the larger Asian H. erectus hypodigm than are the Ngandong fossils. The Chinese specimens differ from the others based on their narrower occipitals and frontals for their cranial size. The Chinese sample from Zhoukoudian alone is thus not a good proxy for the morphology and variation seen within Asian H. erectus. Both the Chinese and late Indonesian samples exhibit less variation than does the early Indonesian sample; this along with their shared morphological bauplan suggests a common origin and no more than subspecific differentiation. This shared morphology, despite regional differences, was likely maintained by the increasing intensity of multiple glaciations (and longer‐lasting land bridge connections) between mainland and island Southeast Asia during the last million years. Am J Phys Anthropol 118:301–323, 2002. © 2002 Wiley‐Liss, Inc.
Normal neuroanatomical variation in the human brain: An MRI‐volumetric study
Authors: Allen John S. , Damasio Hanna , Grabowski Thomas J. 
Published: September 2002

AbstractNormative data on the in vivo size of the human brain and its major anatomically defined subdivisions are not readily available. In this study, high‐resolution magnetic resonance imaging was used to measure regional brain volumes in 46 normal, right‐handed adults (23 men, 23 women) between the ages of 22–49 years. Parcellation of the brain was based on neuroanatomical landmarks. The following brain regions were measured: the cerebral hemispheres, frontal lobe, temporal lobe, parietal lobe, occipital lobe, cingulate gyrus, insula, cerebellum, corpus callosum, and lateral ventricles. Males tend to be significantly larger than females, for the whole brain and for nearly all of its major subdivisions, including the corpus callosum. However, the proportional sizes of regions relative to total volume of the hemisphere are remarkably similar in males and females. Variation in size of region is always greater than variation in proportional representation. Asymmetries in brain regions are not profound, with the exception of the cingulate gyrus, which is larger in the left hemisphere. Brain regions are highly correlated in size, with the exception of the lateral ventricles. After controlling for hemisphere size, the volumes of the frontal and parietal lobes are significantly negatively correlated. The occipital lobe tends to be less sexually dimorphic than other major lobes, and less correlated with other brain regions for volume. These results have implications for understanding whether or not certain sectors of the brain have shown relative expansion over the course of hominid and hominoid evolution. Am J Phys Anthropol 118:341–358, 2002. © 2002 Wiley‐Liss, Inc.
Dichloroacetate exerts therapeutic effects in transgenic mouse models of Huntington's disease
Authors: Andreassen Ole A. , Ferrante Robert J. , Huang Hsueh‐Meei , Dedeoglu Alpaslan , Park Larry , Ferrante Kimberly L. , Kwon Jennifer , Borchelt David R. , Ross Christopher A. , Gibson Gary E. , Beal M. Flint 
Published: September 2002

AbstractDichloroacetate (DCA) stimulates pyruvate dehydrogenase complex (PDHC) activity and lowers cerebral lactate concentrations. In the R6/2 and N171‐82Q transgenic mouse models of Huntington's disease (HD), DCA significantly increased survival, improved motor function, delayed loss of body weight, attenuated the development of striatal neuron atrophy, and prevented diabetes. The percentage of PDHC in the active form was significantly reduced in R6/2 mice at 12 weeks of age, and DCA ameliorated the deficit. These results provide further evidence for a role of energy dysfunction in HD pathogenesis and suggest that DCA may exert therapeutic benefits in HD.
Effects of the fractionated components of the seaweed Hizikia fusiforme Okam. on arsenic metabolism in rats administered a large dose of arsenate
Authors: Katayama Masayuki , Kouya Yukie , Furusawa Chiduru , Sakiyama Chie , Kaise Toshikazu , Sugawa‐Katayama Yohko 
Published: September 2002

AbstractTo investigate factors in the seaweed Hijiki affecting arsenic metabolism in rats, we extracted pulverized Hijiki samples with hot 0.1 M NaOH, and neutralized the extract with HCl. After centrifugation at 10 000 rpm for 30 min, the supernatants and the residues were lyophilized, mixed with cellulose, and added to the standard diet for rats. The rats were divided into three groups as follows: (1) group C, fed the standard diet, (2) group H‐sup, fed a diet containing the extracted soluble fraction, and (3) group H‐rsd, fed a diet containing the residues. After feeding the diets for 12 days, the respective groups were divided into two sub‐groups; one of them was administered a large oral single dose (40% of the LD50) of an aqueous solution of sodium arsenate, Na2AsHO4·7H2O, 24 h before sacrifice. Samples of urine were gathered before and after the administration of arsenate. Arsenic compounds in the urine and serum were analyzed by high‐performance liquid chromatography–inductively coupled plasma mass spectrometry system. The patterns of the arsenic compounds suggested that some Hijiki components accelerated arsenic metabolism, e.g. methylation, in rats. Copyright © 2002 John Wiley & Sons, Ltd.
Accumulation of arsenic by Traustochytrium sp. CHN‐1 from Seto Inland Sea
Authors: Yamaoka Yukiho , Carmona Marvelisa L. , Naganuma Tuyoshi , Jin Kazuo 
Published: September 2002

AbstractThe accumulation of arsenic by Traustochytrium sp. CHN‐1 (Labyrinthulids) was examined by using a medium [2% (w/v) glucose, 0.1% (w/v) yeast extract, 0.1% (w/v) peptone in a half salt concentration of sea water] containing arsenic as As(V), As(III). Traustochytrium sp. CHN‐1 was grown in 1/2 sea water medium [2% (w/v) glucose, 0.1% (w/v) yeast extract, 0.1% (w/v) peptone] containing an arsenate (As(V)) at up to 1000 mg dm−3 and arsenite (As(III)) at up to 50 mg dm3. The cells died even at [As(III)]‐100 mg dm−3. These results suggested that the order of growth inhibition of Traustochytrium sp. CHN‐1 by arsenic was As(III) > As(V). The biomass of Traustochytrium sp. CHN‐1 decreased with an increase of the surrounding arsenic concentration. On the other hand, the arsenic concentration in cells increased with an increase of the surrounding arsenic concentration. Arsenic compounds were extracted with methanol/water (1:1) from a freeze‐dried sample of Traustochytrium sp. CHN‐1. The extracts were analyzed by high‐performance liquid chromatography, with an inductively coupled plasma mass spectrometer serving as an arsenic‐specific detector. Arsenite, arsenate, monomethylarsonic acid (MMAA), dimethylarsinic acid (DMAA) and arsenosugar were identified in Traustochytrium sp. CHN‐1. The order of arsenic species in Traustochytrium sp. CHN‐1 was As(V) > DMAA > As(III) > MMAA > arsenosugar at [As]‐10 mg dm−3 in the medium. Detoxification of arsenic by cells was probably achieved by methylation. Copyright © 2002 John Wiley & Sons, Ltd.
Study of in vitro cytotoxicity of arsenocholine, a trimethyl arsenic compound in seafood
Authors: Sakurai Teruaki , Ochiai Masayuki , Kojima Chikara , Kumata Hidetoshi , Fujiwara Kitao 
Published: September 2002

AbstractWe examined the in vitro cytotoxic effects of an organic arsenic compound contained in seafood, viz. the trimethyl (2‐hydroxyethyl)‐arsonium cation, or arsenocholine (AsCho), on some murine immune effector cells, such as splenocytes, thymocytes, Peyer's patch lymphocytes, peritoneal macrophages and bone marrow (BM) cells using synthesized pure material. We found that AsCho had no cytotoxicity on most immune effector cells, even at concentrations over 10 mmol dm−3, and it slightly but significantly enhanced the viability of BM cells at doses over 100 µmol dm−3. This biological effect of AsCho on BM cells might be direct rather than due to autocrine mechanisms mediating some factors secreted by AsCho‐stimulated BM cells, because the culture supernatants of BM cells pre‐stimulated with AsCho did not influence the viability of other fresh BM cells. It is interesting that this unique biological effect was found in AsCho, an organic arsenic compound contained in some marine animals that are ingested daily as seafood in many countries. Copyright © 2002 John Wiley & Sons, Ltd.
Arsenic speciation in whelks, Buccinum undatum
Authors: Lai Vivian W.‐M. , Beach Anda S. , Cullen William R. , Ray Sankar , Reimer Kenneth J. 
Published: September 2002

AbstractThe arsenic species present in the foot muscle of whelks, Buccinum undatum, collected from Newfoundland, Canada, were characterized by using high‐performance liquid chromatography–inductively coupled plasma mass spectrometry. All samples contain high amounts of arsenic, mostly over 100 µg g−1 (as arsenic, dry weight basis), and one sample contained up to 1360 µg g−1. These values are considerably higher than those reported in other gastropods. Speciation studies of representative samples revealed arsenobetaine as the major water‐soluble arsenic compound, together with trace amounts of an arsenosugar. No inorganic arsenic species were detected in the sample extracts, indicating that consumption of the whelks poses little human risk. Copyright © 2002 John Wiley & Sons, Ltd.
Fracture behavior of NR and SBR vulcanizates filled with ground rubber having uniform particle size
Authors: Han Seung‐Cheol , Han Min‐Hyeon 
Published: September 2002

AbstractThe use of recycled rubber including ground scrap vulcanizates in rubber compounds was studied. When ground rubber was incorporated into rubber compounds, the physical properties, especially the tensile strength, were deteriorated compared to the virgin rubber compound. Also, incorporating ground rubber caused a change of the cure behavior via migration of sulfur or an accelerator between the virgin rubber matrix and the ground rubber vulcanizate. In this study, the fracture behavior and abrasion property of carbon black‐filled SBR and NR compounds containing ground rubber vulcanizate were investigated. Also, the effect of the particle size or loading volume of ground rubber powder on those properties was studied. Four different sizes, 420–600, 177–250, 125–150, and 75–88 μm, of ambient ground rubber powder recycled from waste tire were selected and used in the compounding. The loading amounts of ground rubber powder were 10, 30, and 50 phr. The flex crack growth of SBR‐ and NR‐based compounds was altered by the addition of ground rubber particles. More delayed crack growth was observed with an increasing loading volume and decreasing particle size of the ground rubber powders, and this behavior was more prominent in SBR than in NR compounds. Tangent delta, a direct measure of internal energy dissipation, increased with an increasing loading volume of the ground rubber particles. The abrasion rate of ground rubber‐filled compounds was more dependent on the size of the abrasion pattern than on the loading level or particle size of the ground rubber powders. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2491–2500, 2002
Mechanical properties of poly(N‐isopropyl‐acrylamide‐co‐itaconic acid) hydrogels
Authors: Quintana José R. , Valderruten Nora E. , Katime Issa 
Published: September 2002

AbstractHydrogels of N‐isopropylacrylamide and itaconic acid were synthesized with different monomer ratios and with two crosslinking agent concentrations. The different xerogels were immersed in water and the swelling process was conducted up to equilibrium conditions at two temperatures (22 and 37°C). These temperatures are lower and higher than the transition temperature shown by PNIPA hydrogels. The mechanical properties of the different solvated hydrogels were examined by oscillatory shear measurements at 22 and 37°C. The copolymer volume fraction and the elastic storage modulus of the hydrogels decreased as the itaconic acid percentage in the copolymer increased. This behavior was attributed to the higher hydrophilic character of the itaconic acid comonomer. Effective crosslinking density, molar mass between crosslinks, and the polymer–solvent interaction parameter were determined from the experimental values of the elastic storage moduli and the copolymer volume fractions. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2540–2545, 2002
Poly(1,2‐diaminobenzene) and poly(1,3‐diaminobenzene): Synthesis, characterization, and properties
Authors: Sánchez C. O. , Rivas B. L. 
Published: September 2002

AbstractPoly(1,2‐diaminobenzene) (1,2‐DAB) and poly(1,3‐diaminobenzene) (1,3‐DAB) have been synthesized by using ammonium persulfate as oxidizing agent in the presence and in the absence of the following metal ion salts: CuCl2, NiCl2, and CoCl2 with different HCl concentrations. The products showed a different content of the metal ion depending on the HCl concentration. The polymers were characterized by Fourier transform infrared (FTIR), ultraviolet‐visible (UV‐Vis) spectroscopy, thermal analysis, and electrical conductivity. The polymerization yield depended on the presence of metal ions that can react as oxidizing reagents and/or catalysts. The polymerization mechanism depended on the position of the substituent. For poly(1,2‐DAB) a ladder‐type structure was obtained, and for poly(1,3‐DAB) one similar to that of polyaniline. The thermal stability increased as the metal ion content in the polymer matrix increased. The electrical conductivity of the polymer did not depend on the metal ion content in the polymer. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2564–2572, 2002
Eucalyptus Kraft pulp fibers as an alternative reinforcement of silicone composites. I. Characterization and chemical modification of Eucalyptus fibers with organosilane coupling agent
Authors: Redondo S. U. A. , Radovanovic E. , Gonçalves M. C. , Yoshida I. V. P. 
Published: September 2002

AbstractIn this study, bleached Eucalyptus fibers obtained by a Kraft pulping process were characterized prior to and after chemical modification with a silane coupling agent, vinyltriethoxysilane, for use as an alternative additive in composites based on silicone. The presence of a silane coating on the fiber surface was observed by infrared, energy dispersive, and X‐ray photoelectron spectroscopies. The morphology of the fibers was investigated by field emission scanning electron microscopy. The untreated fibers were ribbon‐shaped and had a rough surface, due to the presence of fibrils. The coating reaction conducted in ethanol gave rise to loose fibrils and a more rough surface compared with those of untreated fibers. A smoother surface was observed when fibers were modified in tetrahydrofuran. The surface topography of the fibers was also examined by atomic force microscopy. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2573–2579, 2002
Fracture behavior of vinylester resin matrix composites reinforced with alkali‐treated jute fibers
Authors: Ray Dipa , Sarkar B. K. , Rana A. K. 
Published: September 2002

AbstractJute fibers were treated with 5% NaOH solution for 4 and 8 h, respectively, to study the mechanical and impact fatigue properties of jute‐reinforced vinylester resin matrix composites. Mechanical properties were enhanced in case of fiber composites treated for 4 h, where improved interfacial bonding (as evident from scanning electron microscopy [SEM]) and increased fiber strength properties contributed effectively in load transfer from the matrix to the fiber; but their superior mechanical property was not retained with fatigue, as they showed poor impact fatigue behavior. The fracture surfaces produced under a three‐point bend test and repeated impact loading were examined under SEM to study the nature of failure in the composites. In case of untreated fiber composites, interfacial debonding and extensive fiber pullout were observed, which lowered the mechanical property of the composites but improved their impact fatigue behavior. In composites treated for 4 h under repeated impact loading, interfacial debonding occurred, followed by fiber breakage, producing a sawlike structure at the fracture surface, which lowered the fatigue resistance property of the composites. The composites with fibers treated with alkali for 8 h showed maximum impact fatigue resistance. Here, interfacial debonding was at a minimum, and the fibers, being much stronger and stiffer owing to their increased crystallinity, suffered catastrophic fracture along with some microfibrillar pullout (as evident from the SEM micrographs), absorbing a lot of energy in the process, which increased the fatigue resistance property of the composites. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2588–2593, 2002
Study of the thermal behavior of alkali‐treated jute fibers
Authors: Ray Dipa , Sarkar B. K. , Basak R. K. , Rana A. K. 
Published: September 2002

AbstractJute fibers were treated with 5% NaOH solution for 2, 4, 6, and 8 h to study the performance of the fibers as a reinforcing material in the composites. Thermal analysis of the fibers was done by the DTG and DSC technique. The moisture desorption was observed at a lower temperature in the case of all the treated fibers, which might be a result of the increased fineness of the fibers, which provides more surface area for moisture evaporation. The decrease in percentage moisture loss for the fibers treated with alkali for 6 and 8 h could be the result of the increased crystallinity of the fibers. The percentage degradation of the hemicellulose decreased considerably in all the treated fibers, conforming to the fact that the hemicellulose content was lowered on alkali treatment. The decomposition temperature for α‐cellulose was lowered to 348°C from 362.2°C for all the treated fibers, and the residual char formation increased to a significant extent. The enthalpy for the thermal degradation of α‐cellulose showed a decreasing trend for the fibers treated for 2 and 4 h, which could be caused by the initial loosening of the structure, followed by an increase in the enthalpy value in the case of the 6‐ and 8‐h‐alkali‐treated fibers resulting from increased crystallinity, as evident from the X‐ray diffraction. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2594–2599, 2002
Use of amidoximated acrylonitrile/N‐vinyl 2‐pyrrolidone interpenetrating polymer networks for uranyl ion adsorption from aqueous systems
Authors: Pekel Nursel , Şahiner Nurettin , Güven Olgun 
Published: September 2002

AbstractPoly(N‐vinyl 2‐pyrrolidone) (PVP)/acrylonitrile (AN) interpenetrating polymer networks (IPNs) were synthesized and amidoximated for the purpose of uranyl ion adsorption. The adsorption of amidoximated IPNs was studied from different uranyl ion solutions (850, 1000, 1200, 1400, and 1600 ppm). The result of all our adsorption studies showed that the bonding between UO‐amidoxime groups complied with the Langmuir‐type isotherm. The adsorption capacity was found as 0.75 g UO/g dry amidoximated IPN. In order to increase the UO ion adsorption capacity the amidoximated IPN was treated with alkali, but no significant increase could be observed. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2324–2329, 2001