bluuebunny/crossref_metadata_2025_split huggingface dataset:
White matter tract alterations in fragile X syndrome: Preliminary evidence from diffusion tensor imaging
Authors: Barnea‐Goraly Naama , Eliez Stephan , Hedeus Maj , Menon Vinod , White Christopher D. , Moseley Michael , Reiss Allan L. 
Published: March 2003

AbstractFragile X syndrome, the most common form of hereditary mental retardation, causes disruption in the development of dendrites and synapses, the targets for axonal growth in the central nervous system. This disruption could potentially affect the development, wiring, and targeting of axons. The current study utilized diffusion tensor imaging (DTI) to investigate whether white matter tract integrity and connectivity are altered in fragile X syndrome. Ten females with a diagnosis of fragile X syndrome and ten, age matched, female control subjects underwent diffusion weighted MRI scans. A whole brain analysis of fractional anisotropy (FA) values was performed using statistical parametric mapping (SPM). A follow‐up, regions‐of‐interest analysis also was conducted. Relative to controls, females with fragile X exhibited lower FA values in white matter in fronto‐striatal pathways, as well as in parietal sensory‐motor tracts. This preliminary study suggests that regionally specific alterations of white matter integrity occur in females with fragile X. Aberrant white matter connectivity in these regions is consistent with the profile of cognitive and behavioral features of fragile X syndrome, and potentially provide additional insight into the detrimental effects of suboptimal levels of FMRP in the developing brain. © 2003 Wiley‐Liss, Inc.
Modest evidence for linkage and possible confirmation of association between NOTCH4 and schizophrenia in a large veterans affairs cooperative study sample
Authors: Skol A.D. , Young K.A. , Tsuang D.W. , Faraone S.V. , Haverstock S.L. , Bingham S. , Prabhudesai S. , Mena F. , Menon A.S. , Yu Chang‐En , Rundell Paul , Pepple J. , Sauter F. , Baldwin C. , Weiss D. , Collins J. , Keith T. , Boehnke M. , Schellenberg G.D. , Tsuang M.T. 
Published: March 2003

AbstractWei and Hemmings [2000: Nat Genet 25:376–377], using 80 British parent–offspring trios, identified a number of NOTCH4 variants and haplotypes that showed statistically significant evidence of association to schizophrenia. Specifically, the 10 repeat allele of a (CTG)n marker and the 8 repeat allele of a (TAA)n marker demonstrated excess transmission to affected individuals; SNP21 and haplotypes SNP2‐(CTG)n and SNP12‐SNP2‐(CTG)n also showed significant associations. In an attempt to replicate these findings, we tested for linkage and association between the same five markers used by Wei and Hemmings in 166 families collected from a multi‐center study conducted by the Department of Veterans Affairs (DVA) Cooperative Study Program (CSP). The families include 392 affected subjects (schizophrenia or schizoaffective disorder, depressed) and 216 affected sibling pairs. The families represent a mix of European Americans (n = 62, 37%), African Americans (n = 60, 36%), and racially mixed or other races (n = 44, 27%). We identified moderate evidence for linkage in the pooled race sample (LOD = 1.25) and found excess transmission of the 8 (P = 0.06) and 13 (P = 0.04) repeat alleles of the (TAA)n marker to African American schizophrenic subjects. The 8 and 13 repeat alleles were previously identified to be positively associated with schizophrenia by Wei and Hemmings [2000: Nat Genet 25:376–377] and Sklar et al. [2001: Nat Genet 28:126–128], respectively. © 2003 Wiley‐Liss, Inc.
Family‐based and case‐control association studies of catechol‐O‐methyltransferase in attention deficit hyperactivity disorder suggest genetic sexual dimorphism
Authors: Qian Qiujin , Wang Yufeng , Zhou Rulun , Li Jun , Wang Bing , Glatt Stephen , Faraone Stephen V. 
Published: March 2003

AbstractAttention deficit hyperactivity disorder (ADHD) is the most common childhood‐onset behavioral disorder. Boys are more often affected than girls. Family, twin, and adoption studies have supported a strong genetic basis. Some studies show that a catechol‐O‐methyltransferase (COMT) polymorphism affecting enzyme activity was associated with personality characteristics and diseases, such as novelty‐seeking personality, substance abuse, and heroin addiction, whose features are similar to ADHD or are associated with ADHD. These findings suggest that the COMT gene may be a candidate gene for ADHD. TDT, HHRR, and case‐control association studies were conducted within a sample of 202 nuclear ADHD families, 340 ADHD cases, and 226 controls in the Han Chinese population. Diagnoses and ADHD subtypes were ascertained according to DSM‐IV criteria using American Clinical Diagnostic Interviewing Scales. The HHRR analysis suggested that the low enzyme‐activity COMT Met allele was preferentially transmitted to ADHD boys (160 trios, χ2 = 3.858, P = 0.05, df = 1) but not girls. This association is particularly pronounced among male ADHD probands without any comorbidity (50 trios, HHRR: χ2 = 5.128, P = 0.024, df = 1; TDT: χ2 = 4.558, P = 0.033, df = 1), especially the ADHD‐I subtype (32 trios, HHRR: χ2 = 5.792, P = 0.016, df = 1; TDT: χ2 = 5.333, P = 0.021, df = 1). The case‐control study revealed that the Val allele was more frequent in females meeting ICD‐10 or DSM‐IV criteria for ADHD than in female controls (86 and 79.5%, respectively, χ2 = 4.059, P = 0.044, df = 1). Although these results suggest the COMT gene exerts some influence on the risk for ADHD in the Han Chinese population, given the potential for Type I error, these findings require replication before drawing definitive conclusions. © 2003 Wiley‐Liss, Inc.
NOTCH4 and the frontal lobe in schizophrenia
Authors: Wassink Thomas H. , Nopoulos Peggy , Pietila Jennifer , Crowe Raymond R. , Andreasen Nancy C. 
Published: March 2003

AbstractNOTCH4 is a developmentally expressed gene recently reported to be in linkage disequilibrium (LD) with schizophrenia. We investigated this finding in our sample of subjects, focusing on an exonic (CTG)n polymorphism, examining not only the association of this polymorphism with the disease phenotype, but also its effect on frontal lobe brain morphology and cognitive function in both affected individuals and a psychiatrically normal comparison group. While we did not find any association or LD with schizophrenia, we identified striking effects of NOTCH4 variability on the trait measures. Within the respective schizophrenia and comparison groups, NOTCH4 allelic variability was correlated with differences in measures of frontal lobe cognitive performance and frontal lobe brain tissue volumes that were intuitively congruent. These within‐group effects, however, were in opposite directions across groups. These findings may reflect the interaction of NOTCH4 with the underlying genetic and phenotypic complexity that characterizes both schizophrenia and normal cognition and brain development. © 2003 Wiley‐Liss, Inc.
Mechanisms of force and power production in unsteady ricochetal brachiation
Authors: Usherwood James R. , Larson Susan G. , Bertram John E.A. 
Published: March 2003

AbstractBrachiators travel by swinging beneath handholds, and it is not obvious how these animals manage to accelerate and decelerate in a horizontal direction, especially when moving rapidly. Most previous analyses focused on brachiation in highly constrained laboratory conditions that induced steady‐state locomotion. Emerging understanding of brachiation suggests that much of gibbon locomotory behavior and morphology must be considered within the context of the complexities of the natural environment: the forest canopy is three‐dimensional, with high variation in handhold availability and properties. The goal of this paper is to quantify the active mechanisms by which gibbons can dynamically control their velocity.Force production and kinematics were analyzed from a white‐handed gibbon Hylabates lar during ricochetal brachiation. Both the mechanisms of force production and power input may be inferred for accelerating and decelerating brachiation by combining force data with kinematics. Examples of steady‐state, accelerating, and decelerating ricochetal brachiation are highlighted.Gibbons are able to produce net horizontal impulses by releasing early (resulting in a loss of potential energy, but an accelerating horizontal impulse) or delaying release (associated with an increase in potential energy, and a decelerating horizontal impulse).Torque about the shoulder, leg‐lifting (or dropping), and elbow flexing (or straightening) are discussed as potential mechanisms for controlling energy within the brachiating system. Of these possibilities, leg‐lifting and arm‐flexing were observed as mechanisms of adding mechanical energy. Net energy loss, and substantial torques about the shoulder, were not observed. Am J Phys Anthropol 120:364–372, 2003. © 2003 Wiley‐Liss, Inc.
Macroscopic and microscopic analyses of linear enamel hypoplasia in Plio‐Pleistocene South African hominins with respect to aspects of enamel development and morphology
Authors: Guatelli‐Steinberg Debbie 
Published: March 2003

AbstractThis study uses macroscopic and microscopic methods to analyze the expression of linear enamel hypoplasia (LEH) in Plio‐Pleistocene South African hominins. LEH is a developmental defect of enamel that is used in many anthropological contexts as a physiological stress indicator. Previous research has not settled the question as to whether differences in LEH expression exist between Paranthropus and Australopithecus and if they exist, to what extent these differences might be explained simply by taxonomic differences in enamel development and morphology rather than by differential stress experience. In this study, the analysis of LEH is conducted with respect to differences between Paranthropus and Australopithecus in aspects of enamel development and morphology that are thought to influence LEH expression. Two factors impacting LEH expression are considered: the duration of enamel formation, and the spacing of perikymata. It is predicted that if the first factor strongly influences the expression of LEH, then there should be fewer defects per tooth in Paranthropus because of its abbreviated crown formation spans (and fast extension rates) relative to Australopithecus. It is also predicted that because Australopithecus has more densely packed perikymata in comparable regions of the crown than Paranthropus, this taxon should, on average, have narrower defects than Paranthropus. To address these questions, 200 Australopithecus and 137 Paranthropus teeth were examined for LEH, and the analysis of defect width with respect to perikymata spacing was conducted on tooth impressions examined under a scanning electron microscope using INCA (Oxford Instruments) measurement software. Data support the first prediction: Australopithecus does have significantly more defects per canine tooth than Paranthropus. Data do not support the second prediction in large part because several Australopithecus specimens have wide groove defects in which perikymata are not visible and enamel is irregular. Such wide grooves are not predicted by perikymata spacing such that alternative explanations, including taxonomic differences in ameloblast sensitivity and the duration/severity of disruptions to enamel growth, must be considered. Am J Phys Anthropol 120:309–322, 2003. © 2003 Wiley‐Liss, Inc.
Organische Template zur Formgebung anorganischer Materialien
Authors: van Bommel Kjeld J. C. , Friggeri Arianna , Shinkai Seiji 
Published: March 2003

AbstractDie Wissenschaft wird wie die Kunst und Architektur von den faszinierenden Formen und Mustern der Natur beeinflusst. Die Mechanismen, die zu organischen, anorganischen und bioorganischen Strukturen führen, wurden in der Physik und Biologie intensiv erforscht, aber auch die Chemie interessiert sich für die Konzepte, auf denen die Bildung regelmäßiger Formen beruht. Während in der Organischen und insbesondere der Supramolekularen Chemie die Synthese großer Überstrukturen bereits früh mit großem Erfolg umgesetzt wurde, gelang es innerhalb der Anorganischen Chemie erst in den letzten Jahren, Verfahren zur Steuerung der Struktur anorganischer Materialien auf mikroskopischer und nanoskopischer Ebene zu entwickeln. Einer der erfolgreichsten Ansätze zur Herstellung anorganischen Strukturen beruht dabei auf der Verwendung organischer und bioorganischer Template, einer Methode, deren Leistungsfähigkeit in diesem Aufsatz vorgestellt werden soll.
Preparation and characterization of modified starch‐based plastic film reinforced with short pulp fiber. I. Structural properties
Authors: Kim Dae‐Hyun , Na Seong‐Ki , Park Jong‐Shin 
Published: March 2003

AbstractNative corn starch‐ and hydroxypropylated starch (HPS‐) based plastic films were prepared using the short pulp fiber as the reinforcement and the glycerol as the plasticizer. Starch (or HPS) films showed different X‐ray diffraction patterns with the A‐type of native corn starch powder. The crystallinity of films increased with pulp content, but decreased with glycerol content and degree of substitution by hydroxypropylation. Also, the intensity of peaks at 2θ = 15.3 and 17.3° decreased with glycerol content and degree of substitution. The water uptake of films as a function of the relative humidity decreased with pulp content and degree of substitution by hydroxypropylation, but increased with glycerol content. Differential scanning calorimetry (DSC) thermograms showed that the glass transition temperature of films decreased and the endothermic peaks at the melting temperature broadened due to the plasticizing effect and the decrease of the crystallinity, which were caused by the addition of glycerol and the hydroxypropylation. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2100–2107, 2003
Preparation and characterization of modified starch‐based plastic film reinforced with short pulp fiber. II. Mechanical properties
Authors: Kim Dae‐Hyun , Na Seong‐Ki , Park Jong‐Shin 
Published: March 2003

AbstractNative corn starch‐ and hydroxypropylated starch (HPS‐) based plastic films were prepared using the short pulp fiber as the reinforcement and the glycerol as the plasticizer. The results of tensile test showed that the strain and stress at break and elastic modulus increased with pulp content. With glycerol content, the strain at break increased considerably, but the breaking stress and elastic modulus decreased. And the stress–strain curves showed that the brittleness problem of films was overcome by the pulp, glycerol, and water content. The hydroxypropyl starch films showed results similar to those of the native starch films. The results of the three‐point bending test showed that maximum deflection, flexural strength, and specific work increased with pulp content, but the flexural modulus was the highest at a pulp content of 20%. And with the glycerol content, the maximum deflection and specific work of rupture increased, but the bending elastic modulus decreased. The hydroxypropyl starch films showed results similar to those of native starch films as far as the maximum deflection and flexural strength were concerned, but the bending elastic modulus and specific work of the hydroxypropyl starch films were considerably lower than those of starch films. So it was concluded that the flexibility of films was improved by the hydroxypropylation. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2108–2117, 2003
pH‐sensitive dimethylaminoethyl methacrylate (DMAEMA)/acrylamide (AAm) hydrogels: Synthesis and adsorption from uranyl acetate solutions
Authors: Yıldız Berna , Işık Belma , Kış Mehmet , Birgül Özgen 
Published: March 2003

AbstractA random copolymer of dimethylaminoethyl methacrylate (DMAEMA) and acrylamide(AAm) [poly(DMAEMA/AAm)], with a pH‐sensitive character, was prepared by a redox polymerization method. Increasing the DMAEMA content of the gel, the pH, and the ionic strength of the solution decreased the swelling ratios of the hydrogels. The adsorption of poly(DMAEMA/AAm) hydrogels from uranyl acetate (UA) solutions was studied at different pHs. The adsorption capacity of hydrogels increased from 200 to 1200 mg of UA per gram of dry hydrogel with increasing pH of the adsorption solution. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2028–2031, 2003
Synthesis of poly(dodecyl methacrylate)s and their drag‐reducing properties
Authors: Ma Yuxin , Zheng Xilai , Shi Fengmei , Li Yue , Sun Shoujia 
Published: March 2003

AbstractDodecyl methacrylate was synthesized as the intermediate monomer for the preparation of poly(dodecyl methacrylate)s, which were synthesized with emulsion polymerization techniques. The intrinsic viscosities were measured, and the viscosity‐average molecular weights were calculated. Polymers of dodecyl methacrylate with ultrahigh molecular weights (viscosity‐average molecular weight > 107) were synthesized through orthogonal experiments. The drag‐reduction properties of these polymers were studied in kerosene. The drag‐reducing behavior of these polymers exhibited a strong dependence on the molecular weight and Reynolds number, and these polymers could be used as effective oil‐soluble drag reducers and had good shear stabilities. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1622–1626, 2003
Effect of processing conditions on mechanical and viscoelastic properties of biocomposites
Authors: Ali R. , Iannace S. , Nicolais L. 
Published: March 2003

AbstractTo study the effects of processing conditions on the viscoelastic and mechanical properties of biodegradable composites, we prepared several composites based on sisal fibers and biodegradable polymers. The effects of processing conditions such as the speed of rotation, temperature, and time of mixing were investigated. The mechanical and viscoelastic properties of these composites were affected by the processing conditions. This was principally due to the modification of the initial aspect ratio of the natural fibers as a result of the shear stresses that developed in the mixer during the compounding. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1637–1642, 2003
On the relationship between modulus of elasticity and microhardness
Authors: Zamfirova Galina , Lorenzo Vicente , Benavente Rosario , Pereña José M. 
Published: March 2003

AbstractThe correlation between the modulus of elasticity, on the one side, and Vickers microhardness and total microhardness, on the other side, was analyzed in the case of ultrahigh molecular weight polyethylenes. An extension of the application of the power relation between microhardness and the modulus (MH = aEb) obtained by different methods was suggested. A linear dependence between constants obtained by Vickers and total microhardness measurements and other different techniques of modulus measurement was established, which signifies that both microhardness characteristics change their sensitivity toward the modulus in a similar way. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1794–1798, 2003
Direct observation of the main cell wall components of straw by atomic force microscopy
Authors: Yan Lifeng , Zhu Qingshi 
Published: March 2003

AbstractCellulose, hemicellulose, and lignin are the main cell wall components of straw. After removal of the wax and the major portion of lignin, the remaining components of the cell wall surface of straw were determined by atomic force microscopy, which revealed a network structure of cellulose and hemicellulose, and some lignin localized on the surface of the network, consistent with the cell wall model suggested by other researchers. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2055–2059, 2003
Synthesis of a polyurethane–chitosan blended polymer and a compound process for shrink‐proof and antimicrobial woolen fabrics
Authors: Shih Chung‐Yang , Huang Kuo‐Shien 
Published: March 2003

AbstractThe purpose of this study was to develop a finishing process to improve the shrinkage and anti microbial properties of woolen fabrics. First, polyurethane (PU) prepolymers were synthesized from poly(ethylene glycol) (PEG) of different molecular weights. Next, the PU prepolymers were mixed with chitosan to form blended polymers. Then, these blended polymers were used to treat woolen fabric in a compound process to determine if they could modify the fabric, making it more resistant to shrinkage and bacteria. Our experimental results indicate an improvement in both the shrink‐proof and antimicrobial properties of the fabric with an increase in the temperature or duration of the heat treatment, as well as with an increase in the concentration of the processing agent. However, the yellowing and softness tendency of the fabric shifted towards the opposite, unfavorable direction. The treatment also seems to somewhat improve the strength of the fabric. Furthermore, our results show that the addition of chitosan remarkably increased the shrink‐proof and antimicrobial properties of the treated fabric. Finally, the blended polymer made of PEG with a molecular weight of 600 and chitosan gave the best results of the polymer combinations tested. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2356–2363, 2003
Effect of the temperature on the tensile mechanical behavior of irradiated linear polyethylene
Authors: Vallés E. M. , Failla M. D. 
Published: March 2003

AbstractThe mechanical behavior of two γ‐irradiated linear polyethylenes was determined at 75 and 105°C under tensile stress. Each polymer was crystallized from the melt after different thermal histories so that samples would be obtained with various degrees of crystallinity. Subsequently, they were irradiated in vacuo and at room temperature to total doses ranging from 20 to 200 kGy. The initial crystallinity, dose level, and test temperature determined whether the samples displayed ductile, brittle, or transitional behavior. The yield stress decreased as the temperature increased. The value of the yield stress at a given temperature showed a tendency to increase with dose; this became more evident as the initial crystallinity increased. The extensibility of ductile samples, estimated from the draw ratio after break, decreased with the gel content. For ductile samples, the temperature affected the values of this property when the gel fraction that developed in the samples was relatively low. The effect of temperature became less noticeable when the gel reached values larger than 60%. The ultimate stress, normalized with the crosslinking density, correlated with the draw ratio after break in a way that resembled the type of relationship observed in other crosslinked systems. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1925–1935, 2003
Emulsifier‐free emulsion copolymerization of styrene with methacrylic acid
Authors: Wang Ping‐Hua , Wang Qian‐Wen 
Published: March 2003

AbstractThe study on batch emulsifier‐free emulsion copolymerization of styrene with methacrylic acid was conducted. The copolymerization process was followed by gravimetry, infrared, and transmission electron microscopy. The copolymerization mechanism differs from that of styrene with acrylic acid. The effect of solid content on particle size was examined, and it was found that the particle size was increased as the solid content was increased. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1747–1751, 2003