bluuebunny/crossref_metadata_2025_split huggingface dataset:
Novel SURF1 mutation in a child with subacute encephalopathy and without the radiological features of Leigh Syndrome
Authors: Salviati Leonardo , Freehauf Cindy , Sacconi Sabrina , DiMauro Salvatore , Thoma Janet , Tsai Anne Chun‐Hui 
Published: March 2004

AbstractMutations in SURF1, a gene involved in cytochrome‐c oxidase (COX) assembly, cause COX deficiency and Leigh Syndrome (LS). Typical presentation is in the first year of life, with failure to thrive, psychomotor regression, ataxia, signs of brainstem dysfunction, and peripheral neuropathy. Progression is rapid and patients usually die of respiratory failure before 2 years of age. LS is characterized by symmetrical bilateral lesions in the brainstem and basal ganglia, revealed premortem as signal hyperintensities in T2‐weighted MRI imaging. Here, we describe a 10‐year‐old boy with a novel mutation in SURF1 associated with an unusually mild clinical course. At 39 months, there were no MRI lesions, and a follow‐up MRI at 8 years of age showed only brainstem and cerebellar involvement without lesions in the basal ganglia or subthalamic nuclei. These data confirm that the spectrum of MRI findings in LS is variable and that SURF1 mutations should be considered in patients with encephalomyopathy and COX deficiency even when early MRI findings are negative. © 2004 Wiley‐Liss, Inc.
GM haplotype diversity of 82 populations over the world suggests a centrifugal model of human migrations
Authors: Dugoujon Jean‐Michel , Hazout Serge , Loirat France , Mourrieras Bruno , Crouau‐Roy Brigitte , Sanchez‐Mazas Alicia 
Published: March 2004

AbstractThis study investigates the GM genetic relationships of 82 human populations, among which 10 represent original data, within and among the main broad geographic areas of the world. Different approaches are used: multidimensional scaling analysis and test for isolation by distance, to assess the correlation between genetic variation and spatial distributions; analysis of variance, to investigate the genetic structure at different hierarchical levels of population subdivision; genetic similarity map (geographic map distorted by available genetic information), to identify regions of high and low genetic variation; and minimal spanning network, to point out possible migration routes across continental areas. The results show that the GM polymorphism is characterized by one of the highest amounts of genetic variation observed so far among populations of different continents (Fct = 0.3915,P< 0.0001). GM diversity can be explained by a model of isolation by distance (IBD) at most continental levels, with a particularly significant fit to IBD for the Middle East and Europe. Five peripheral regions of the world (Europe, west and south sub‐Saharan Africa, Southeast Asia, and America) exhibit a low level of genetic diversity both within and among populations. By contrast, East and North African, Southwest Asian, and Northeast Asian populations are highly diverse and interconnected genetically by large genetic distances. Therefore, the observed GM variation can be explained by a “centrifugal model” of modern humans peopling history, involving ancient dispersals across a large intercontinental area spanning from East Africa to Northeast Asia, followed by recent migrations in peripheral geographic regions. Am J Phys Anthropol 123:000–000, 2004. © 2004 Wiley‐Liss, Inc.
Cranial evolution in sakis (Pithecia, Platyrrhini) I: Interspecific differentiation and allometric patterns
Authors: Marroig Gabriel , Cheverud James M. 
Published: March 2004

AbstractPatterns of interspecific differentiation in saki monkey (Pithecia) skulls are quantitatively described. The taxonomic arrangement previously proposed by Hershkovitz ([1987] Am. J. Primatol. 12:387–468) is consistent with quantitative differences in saki morphology. Discriminant analyses on 39 skull traits show that Pithecia species and subspecies are well‐differentiated. Morphological distances (D2) among sakis clearly show the morphological unity of the pithecia‐chrysocephala (Pithecia) and irrorata‐vanzolinii‐monacha (Monacha) species groups. The Pithecia species group is distributed north of the Amazon and has a smaller cranium than the Monacha group, distributed south of that river. Despite the size difference, multivariate static allometric patterns among sakis are quite similar. After removing size and allometric changes in shape from the data, species and subspecies are still differentiated, although to a lesser extent. D2 distances obtained from these scale‐corrected data are similar in magnitude and pattern to the original D2, but show a closer similarity of P. monacha with the Pithecia group. P. monacha is a scaled‐up version of the smaller sakis. Am J Phys Anthropol 124:000–000, 2004. © 2004 Wiley‐Liss, Inc.
Multivariate apportionment of global human craniometric diversity
Authors: Roseman Charles C. , Weaver Timothy D. 
Published: March 2004

AbstractExtensive research in human genetics on presumably neutral loci has shown that the overwhelming majority of human diversity is found among individuals within local populations. Previous apportionments of craniometric diversity are similar to these genetic apportionments, implying that interregionally differing selection pressures have played a limited role in producing contemporary human cranial diversity. Here we show that when cranial variation is independently partitioned using principal components analysis of Mosimann shape variables, some estimates of interregional craniometric differentiation are larger than those for most genetic loci. These estimates are similar to estimates for genetic loci where interregionally differing selection pressures are implicated in producing the observed patterns of variation within and among regions. These results suggest that differences among regions in at least some cranial features, particularly in the nasal region, are in part the product of interregionally differing selection pressures. Moreover, these results have implications for assessing the biological affinities of prehistoric samples that are temporally separated from contemporary human reference populations. Am J Phys Anthropol 124:000–000, 2004. © 2004 Wiley‐Liss, Inc.
Effect of 2‐mercaptobenzothiazole level on kinetics of natural rubber vulcanization
Authors: Wang Ping‐Yue , Qian Hong‐Lian , Yu He‐Ping 
Published: March 2004

AbstractThe kinetics of natural rubber vulcanization were investigated by use of a vulcameter. The vulcanization process before tdis (the time when the accelerators and/or intermediates react to depletion) was expressed in an equation as ln(MH − Mt) = ln A − k1(t − t0)α, which is different from the famous equation of Vut = −[α(k3/k4)]ln[(k2e − k1e)/(k2 − k1)] deduced by Coran. It was found that the rate constants of two vulcanization processes with different reaction mechanisms before and after tdis increase and their activation energies decreased with an increase in 2‐mercaptobenzthiazole (MBT) level. The considerable effect of MBT level on the activation energies of the vulcanization process before tdis and the obvious temperature dependency of the reaction rate of vulcanization process after tdis were observed. The time tdis was shortened with an increase in MBT level, whereas the degree of vulcanization at tdis remained unchanged. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3260–3265, 2004
Synthesis and characteristics of biodegradable copolyesters from the transesterification of poly(butylene adipate‐co‐succinate) and poly(ethylene terephthalate)
Authors: Kim Sang‐Woo , Lim Jeong‐Cheol , Kim Dae‐Jin , Seo Kwan‐Ho 
Published: March 2004

AbstractPoly(butylene adipate‐co‐succinate) (PBAS), an aliphatic polyester, is known for its excellent biodegradability, but its physical and mechanical properties are poor. To improve the physical properties, stiff aromatic rings were added to PBAS through transesterification with poly(ethylene terephthalate) (PET). New biodegradable copolyesters were prepared by the intermolecular ester‐exchange reactions between molten PBAS and PET. The transesterification reaction was carried out at 280°C without a catalyst. The newly synthesized copolyesters were characterized with 1H‐NMR spectroscopy, differential scanning calorimetry, and thermogravimetric analysis. The mechanical properties were measured with a universal test machine, and the biodegradability was also investigated. By the new peaks appearing in 1H‐NMR spectra of the copolyesters, the occurrence of the transesterification reaction between PBAS and PET was confirmed. A reduction of the melting temperature was observed for the copolyesters. The elongations at break of the new copolyesters increased for all compositions and reaction times, in comparison with PBAS. However, the tensile strength decreased with the induction of terephthalate units in the copolyesters. The biodegradability of the copolyesters also depended on the number of terephthalate units. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3266–3274, 2004
Thermal and morphological study of polyurethanes based on Eucalyptus tar pitch and castor oil
Authors: Melo Breno N. , Pasa Vânya M. D. 
Published: March 2004

AbstractThis article presents the results of the synthesis and characterization of environmentally friendly polyurethanes based on renewable polyols, and specially highlights the use of Eucalyptus tar pitch, a byproduct of the charcoal making industry in Brazil, to obtain PUs. Eucalyptus tar pitch and castor oil PUs synthesized with MDI in THF, catalyzed by dibutyltin dilaurate, were prepared with NCO/OH equal to 1, and vacuum cured. The addition of Eucalyptus tar pitch to the formulation of PUs showed a tendency to increase the formation of rigid segments, and consequently, to modify thermal stability. SEM micrographs confirm this behavior, displaying different materials. Homogeneous polyurethane elastomers become rigid and acquire lamella structure with the addition of biopitch, as confirmed by tensile strength assays. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3287–3291, 2004
Synthesis and surface‐active properties of a trisiloxane‐modified oligo(propylene oxide‐block‐ethylene oxide) wetting agent
Authors: Kim Doo‐Won , Noh Si‐Tae 
Published: March 2004

AbstractPolydisperse 1,1,1,3,5,5,5‐heptamethyltrisiloxane‐oligo(propylene oxide‐block‐ethylene oxide) wetting agents were synthesized through the hydrosilylation of 1,1,1,3,5,5,5‐heptamethyltrisiloxane (HMTS) with active hydrogen and allyl oligo(propylene oxide‐block‐ethylene oxide) [allyl oligo(PO‐b‐EO)] with hexachloro dihydrogen platinate(IV) as a catalyst. Allyl oligo(PO‐b‐EO) with a hydrophilic–hydrophobic balance was synthesized through the combination of propylene oxide (PO) and ethylene oxide with allyl alcohol. The wetting agents with a hydrophilic–hydrophobic balance were synthesized. The aqueous solutions of the wetting agents (0.1 wt %) were almost visibly turbid. An increase in the number of hydrophobic groups of HMTS and PO for the wetting agents resulted in a lower critical solution temperature. Lower surface tensions of 20–25 dyn/cm were found above the critical micelle concentration (cmc), and they decreased with an increase in the number of hydrophobic groups. The cmc's were below 0.01 wt %, decreasing with as the number of hydrophobic groups increased. The wetting power and emulsion stability for the oil‐in‐water systems increased as the concentration of the wetting agents increased, and they decreased as the number of hydrophobic groups increased. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3292–3302, 2004
Morphology and properties of isotactic polypropylene modified with hydrocarbon resin MBG273. I. Binary blends
Authors: Cimmino S. , Silvestre C. , della Vecchia G. 
Published: March 2004

AbstractWe investigated a system formed of isotactic polypropylene (iPP) and hydrogenated hydrocarbon resin MBG273 (up to 30 wt % resin) to study the influence of the composition on the morphology, structure, and properties of its blends and derived films. All the blends, after the mixing of the components in the melt and cooling at room temperature, were formed by a crystalline phase of iPP and by one homogeneous phase formed by amorphous iPP and the MBG273 resin. The presence of MBG273 did not influence the crystalline structure of iPP, which remained, for every blend, α‐monoclinic, but it reduced the crystallization temperature and nucleation density of iPP. Differential scanning calorimetry and dynamic mechanical thermal analysis showed an increase in the glass‐transition temperature with the resin content, confirming the formation of one amorphous phase. Tensile property analysis indicated an increase in Young's modulus and a decrease in the elongation at break of films as a function of the resin content in the blends. The water vapor permeability and tensile mechanical properties were related to an increase in the glass transition with the addition of MBG273. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3454–3465, 2004
Rice husk powder–filled polystyrene/styrene butadiene rubber blends
Authors: Zurina M. , Ismail H. , Bakar A. A. 
Published: March 2004

AbstractNatural fibers are rich in cellulose and they are a cheap, easily renewable source of fibers with the potential for polymer reinforcement. The presence of large amounts of hydroxyl groups makes natural fibers less attractive for reinforcement of polymeric materials. Composites made from polystyrene (PS)/styrene butadiene rubber (SBR) blend and treated rice husk powder (RHP) were prepared. The RHP was treated by esterification and acetylation. A similar series of composites was also prepared using maleic anhydride–polypropylene (MA–PP) as a coupling agent. The processing behavior, mechanical properties, effect of thermooxidative ageing, and surface morphology of untreated and chemically modified RHP were studied. There was a decrease in tensile strength (except MA–PP composites), elongation at break, and Young's modulus in chemically treated RHP composites. The postreaction process during thermooxidative ageing enhanced the tensile strength and Young's modulus of the esterified and MA–PP composites. Acetylation treatment was effective in reducing the percentage of water absorption in RHP/PS–SBR composites. In general chemically treated RHP/PS–SBR composites and MA–PP showed a better matrix phase and filler distribution. However, the degree of filler–matrix interaction was mainly responsible for the improvement of mechanical properties in the composites. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3320–3332, 2004
Poly(N‐isopropylacrylamide) grafted to a strongly charged backbone: Thermoresponsive behavior in aqueous solution
Authors: Chourdakis N. , Bokias G. , Staikos G. 
Published: March 2004

AbstractThe thermoresponsive properties in aqueous solution of the graft copolymer poly(acrylic acid‐co‐2‐acrylamido‐2‐methyl propane sulfonic acid)‐g‐poly(N‐isopropylacrylamide) [P(AA‐co‐AMPSA)‐g‐PNIPAM] were studied and compared to the corresponding behavior of the poly(acrylic acid)‐g‐poly(N‐isopropylacrylamide) (PAA‐g‐PNIPAM) graft product. Both products contain about 40% (w/w) of PNIPAM, whereas the backbone, P(AA‐co‐AMPSA), of the first copolymer contains about 40% of AMPSA mole units. The strongly charged P(AA‐co‐AMPSA)‐g‐PNIPAM graft copolymer was water soluble over the whole pH range, whereas the PAA‐g‐PNIPAM copolymer precipitated out from water at pH < 4. As a result, the first product exhibited a temperature‐sensitive behavior in a wide pH range, extended in the acidic region, whereas in semidilute aqueous solutions, an important thermothickening behavior was observed, even at low pH (pH = 3.0). © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3466–3470, 2004
Synthesis of aliphatic polyesters by a chain‐extending reaction with octamethylcyclotetrasilazane and hexaphenylcyclotrisilazane as chain extenders
Authors: Zhao Jing‐Bo , Wu Xiao‐Feng , Yang Wan‐Tai 
Published: March 2004

AbstractAliphatic HO‐terminated polyesters such as poly(diethylene glycol adipate) (PDEGA), poly(ethylene adipate) (PEA), and poly(butylene succinate) (PBS) with molecular weight from 1247 to 1948 were synthesized through condensation polymerization from adipic acid or butanedioic acid with excess diethylene glycol, ethylene glycol, or butylene glycol. From the HO‐terminated polyesters, polyesters with high molecular weight were synthesized by a chain‐extending reaction with octamethylcyclotetrasilazane (OMCT) or hexaphenylcyclotrisilazane (HPCT) as chain‐extenders. Gel permeation chromatography (GPC) characterization shows that the Mn of chain‐extended PDEGA is from 12,644 to 32,870, Mw is from 22,786 to 70,048; Mn of chain‐extended PEA is 11,368, Mw is 19,877; and the Mn of chain‐extended PBS is from 9823 to 39,873, Mw is from 18,823 to 137,192. The chain‐extended polyesters were also characterized by 1H‐NMR spectrum, IR spectra, and DSC spectra. The multiple peaks at 7.37 and 7.67 ppm in the 1H‐NMR spectrum of chain‐extended PDEGA and peaks at 3051.1 and 1593.4 cm−1 in the IR spectrum of the chain‐extended PBS show the evidence of the SiPh2 structure in the polyesters obtained from the chain‐extending reaction. DSC study shows that the bulky SiPh2 units introduced by the chain‐extending reaction lower the regularity of the polyester chains, so the melting point of the chain‐extended PBS and PEA decreases compared to that of the original HO‐terminated PBS and PEA. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3333–3337, 2004
Dyeing of wool with antibiotics to develop novel infection resistance materials for extracorporeal end use
Authors: Choi Hyung‐Min , Bide Martin , Phaneuf Matthew , Quist William , LoGerfo Frank 
Published: March 2004

AbstractTwo antibiotics, doxycycline (Doxy) and ciprofloxacin (Cipro), were applied under a variety of conditions to wool and to hydrolyzed wool at 40°C. Nylon was used as a synthetic control. Sorption of Doxy was much higher in wool than in nylon, whereas sorption of Cipro was similar in both fibers. FTIR spectroscopy confirmed that a drastic increase in sorption of antibiotics by hydrolyzed wool was attributed to an increase in polar functional groups by peptide scission and in oxidized sulfur groups by cystine oxidation. Both sorption and zone of inhibition (ZOI) values were improved by hydrolysis of wool. Wool hydrolyzed for 20 or 40 min at 40°C and dyed with Doxy at 45°C for 3.5 h maintained around 30 mm of ZOI after 24 h of challenge by a simulated flow of blood. Wool hydrolyzed for 60 min at 40°C and dyed with Cipro at 45°C for 3.5 h also maintained its antibiotic activity for an extended time. For the most part, ZOI values for nylon dyed by both antibiotics were zero within 24 h. This technique produced infection‐resistant biomaterials of potential use in extra‐corporeal biomedical and biological applications. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3343–3354, 2004
Binding of methyl orange or ethyl orange dyes by some dioxolane copolymers: Synthesis of the copolymers and thermodynamics of the dye–copolymer interactions
Authors: Ceylan Nilgun Nese , Ilter Zulfiye 
Published: March 2004

AbstractThe extent of binding of methyl orange or ethyl orange by (2‐phenyl‐1,3‐dioxolane‐4‐yl) methyl methacrylate (PDMMA), 2‐hydroxyethyl methacrylate (HEMA), and vinyl‐pyrrolidone (VPy) copolymers has been investigated by the equilibrium dialysis method. The dialysis experiments have been carried out in a Tris (hydroxy methyl) aminomethane buffer (pH = 7) and at the temperatures of 15, 25, and 35°C. The PDMMA‐co‐HEMA and PDMMA‐co‐VPy copolymers have been prepared in the laboratory by using the related monomers in different ratios. The synthesized products were analyzed by Fourier Transform‐infrared spectroscopy (FTIR), proton nuclear magnetic resonance (1H NMR) spectroscopy, differential thermal analysis (DTA), and differential scanning calorimetry (DSC) techniques. The binding extent of the dyes by the copolymers was determined by ultraviolet (UV) absorbance measurements. The results indicate that the extent of binding is relatively higher for ethyl orange than that for methyl orange under identical conditions. The binding slightly decrease with increasing temperature, and it is accompanied with favorable free energy, and exothermic enthalpy change within the temperature range studied. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3355–3361, 2004
Determination of monomer reactivity ratios in styrene/2‐ethylhexylacrylate copolymer
Authors: Kavousian A. , Ziaee F. , Nekoomanesh M. H. , Leamen M. J. , Penlidis A. 
Published: March 2004

AbstractThe monomer reactivity ratios for styrene/2‐ethylhexylacrylate in bulk at 80°C were investigated by studying the resulting copolymer composition via 1H‐NMR. Composition results were summarized and various methods were employed to estimate the reactivity ratios including the use of the Error‐in‐Variables‐Model (EVM) approach by using the Mayo–Lewis model. The estimates of the reactivity ratios from the EVM method are found to be rs = 0.979 and rEHA = 0.292. The resulting copolymer has a tendency toward alternation with an azeotrope of f(styrene) = 0.972. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3368–3370, 2004
Enantioselective esterification reaction using immobilized Candida rugosa lipase on poly(N‐vinyl‐2‐pyrrolidone‐co‐styrene) hydrogel
Authors: Harun A. , Basri M. , Ahmad M. B. , Salleh A. B. 
Published: March 2004

AbstractLipase from Candida rugosa was immobilized on poly(N‐vinyl‐2‐pyrrolidone‐co‐styrene) hydrogel (poly‐(VP‐co‐ST)) with ethylene dimethacrylate and α,α'‐azoisobutyronitrile, which act as crosslinker and initiator, respectively. Three different compositions of monomers were used, namely VP(%):ST(%), 10:90, 50:50, and 70:30 (wt(%)/wt(%)). The immobilized lipases were used in the enantioselective esterification of (R,S)‐2‐(4‐chlorophenoxy)‐propanoic acid with n‐tetradecanol. The optimum reaction condition of the enantioselective esterification for the native lipase and the poly(VP‐co‐ST) hydrogel immobilized lipases was determined with respect to temperature, solvents, and initial water activity (aw). The optimum temperature obtained was 40°C, with the poly(VP‐co‐ST) hydrogel immobilized lipase VP(%)/ST(%):10:90 showing the highest enantiomeric excess. In the solvent effect studies, the best solvents for high enantioselectivity were chloroform and carbon tetrachloride. In the aw studies, optimum αw for NL, VP(%):ST(%), 10:90, and 50:50 was 0.328, while for VP(%):ST(%), 70:30, it was 0.55. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3381–3386, 2004
Synthesis of novel block copolymers containing polyamide4 segments and control of their biodegradability
Authors: Hashimoto Kazuhiko , Sudo Mie , Sugimura Takayuki , Inagaki Yoshiki 
Published: March 2004

AbstractDifferent novel copolymers, ABA‐type block copolymers composed of polyamide4 as outer segments and polyoxyethylene as an inner segment and AB‐ and ABA‐type block copolyamides containing polyamide4 and another hydrophilic polyamide derived from a bicyclic lactam, were synthesized by the anionic ring‐opening polymerization of 2‐pyrrolidone using the corresponding acyllactam‐type macromolecular activators. The degradation rate of both block copolymers containing polyamide4 segments in a composted soil was found to decrease with increasing content of the second segments, although they were also hydrophilic and/or biodegradable. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3492–3498, 2004