bluuebunny/crossref_metadata_2025_split huggingface dataset:
Scale issues in the study of primate foraging: Red colobus of Kibale National Park
Authors: Chapman Colin A. , Chapman Lauren J. , Gillespie Thomas R. 
Published: August 2002

AbstractDiet data have been used to address a number of theoretical issues. We often calculate the proportion of time spent eating different foods (e.g., fruits, leaves) to place species into dietary categories and contrast morphological or behavioral traits among categories. Yet we have little understanding of how flexible species can be in terms of the plant parts and species consumed. To address this issue, we analyzed data on the diets of red colobus monkeys (Procolobus badius) from Kibale National Park, Uganda, to evaluate temporal and spatial variability in the plant parts and species eaten. After considering observer differences and sampling issues, we evaluated how different a group's diet could be if samples were taken in different years. We found that the diet of the same groups showed significant, consistent changes over a 4‐year period. For example, the time spent feeding on leaves increased from 56% in 1994 to 76% in 1998. The plant parts and species eaten by eight groups inhabiting different types of forest (e.g., pristine, logged, riverine) varied among groups. The largest interdemic difference was seen in the use of young leaves (38%). Dietary differences were also found between groups with overlapping home ranges (41–49% overlap). Different subspecies of Procolobus badius also varied in diet; however, this variation was often not of the magnitude documented within Kibale for the same population. The fact that diet can vary considerably over small spatial and short temporal scales within the same species raises the intriguing question as to what level of interspecific difference is biologically significant for addressing particular questions. We conclude that behavioral flexibility blurs our traditional stereotypic assessment of primates; a study of one group that occupies a specific habitat at one point in time may not adequately represent the species. Am J Phys Anthropol 117:349–363, 2002. © 2002 Wiley‐Liss, Inc.
Magnetoencephalographic fields from patients with spontaneous and induced migraine aura
Authors: Bowyer Susan M. , Aurora Sheena K. , Moran John E. , Tepley Norman , Welch K. M. A. 
Published: August 2002

AbstractWe investigate and characterize the magnetoencephalographic waveforms from patients during spontaneous and visually induced migraine aura. Direct current neuromagnetic fields were measured during spontaneous onset of migraine auras in 4 migraine patients, and compared with recordings from 8 migraine‐with‐aura patients and 6 normal controls during visual stimulation of the occipital cortex. Complex direct current magnetoencephalographic shifts, similar in waveform, were observed in spontaneous and visually induced migraine patients, but not in controls. Two‐dimensional inverse imaging showed multiple cortical areas activated in spontaneous and visually induced migraine aura patients. In normal subjects, activation was only observed in the primary visual cortex. Results support a spreading, depression‐like neuroelectric event occurring during migraine aura that can arise spontaneously or be visually triggered in widespread regions of hyperexcitable occipital cortex.
Arsenic compounds in marine sponge (Haliclona permolis, Halichondria japonica, Halichondria okadai and Haliclona sp. white) from Seto Inland Sea, Japan
Authors: Yamaoka Yukiho , Carmona Marvelisa L. , Oclarit Jose M. , Jin Kazuo , Shibata Yasuyuki 
Published: August 2002

AbstractMarine sponges were collected at Hiro or Hatami, Hiroshima Prefecture, Aki Nada in the Seto Inland Sea, Japan. Arsenic compounds were extracted with methanol/water (1:1, v/v) from freeze‐dried samples of the marine sponges Haliclona permolis, Halichondria japonica, Halichondria okadai and Haliclona sp. white. The extracts were analyzed by high‐performance liquid chromatography, with an inductively coupled plasma mass spectrometer serving as an arsenic‐specific detector. Arsenobetaine 5 and the two arsenosugars as 6 and 7 were identified in all samples targeted, and these three compounds accounted for 74 to 96% of the water‐soluble arsenic in all four species of sponge. Arsenosugar was the major arsenic species in all four species of sponge. The most abundant arsenic compound in all four species of sponge was arsenosugar 7, and arsenosugar 6 was only a minor component. The arsenobetaine and arsenosugar concentrations were considerably higher in the three sponges from demospongiae (H. permolis, H. japonica and H. okadai) compared with the single species from calcispongiae (Haliclona sp. white). Copyright © 2001 John Wiley & Sons, Ltd.
Biomethylation and bioaccumulation of arsenic(V) by marine alga Fucus gardneri
Authors: Granchinho Sophia C. R. , Polishchuk Elena , Cullen William R. , Reimer Kenneth J. 
Published: August 2002

AbstractThe brown alga, Fucus gardneri, was collected from Vancouver Island, B.C., Canada. Fucus samples were acclimated in seawater and then exposed to arsenic(V) in artificial seawater, all under axenic conditions. The arsenic species in the Fucus samples were extracted into 1:1 methanol/H2O and identified by using ion‐pairing high‐performance liquid chromatography coupled to inductively coupled plasma mass spectrometry (HPLC–ICP‐MS). Anion‐exchange HPLC–ICP‐MS was used to identify the arsenic species in the growth medium. It was found that ∼73% of the original arsenosugars in the F. gardneri samples were lost during the acclimation period. Arsenite [As(III)] and dimethylarsenate [DMA] concentration increased in the Fucus samples after exposure to arsenate [As(V)]. A small increase in the concentration of an arsenosugar was seen during this period, accompanied by a further decrease in the concentration of two other arsenosugars. The experiments provided very little evidence for the hypothesis that arsenosugars are produced by the macroalgae. Copyright © 2001 John Wiley & Sons, Ltd.
Synthesis of organofunctional silanes with sterically hindered substituents at silicon atoms
Authors: Guliński Jacek , Maciejewski Hieronim , Dąbek Izabela , Zaborski Marian 
Published: August 2002

AbstractOrganofunctional silanes with more sterically hindered substituents at the silicon atom than the typical methoxy (ethoxy) group have lately been frequently used as silane coupling agents, in polymer coupling systems, sol‐gel processes and also as interpenetrating polymer network substrates. New and very efficient synthetic ways leading to organofunctional silanes of the above type with methacryl, amine, chloro and isocyanato functional groups are proposed here. Catalytic transesterification and/or alcoholysis of chloropropyltrialkoxysilanes followed by­nucleophilic substitution has been employed. Copyright © 2001 John Wiley & Sons, Ltd.
Silicon–oxygen‐bonded oligomers having thermoelectric switching properties
Authors: Purkayastha Arup , Baruah Jubaraj B. 
Published: August 2002

AbstractThe electrical properties of siloxane oligomers prepared from the reaction of 1,4‐naphthalenediol or 1,4‐naphthoquinone with diphenylsilane using different palladium catalysts, such as PdCl2, Pd(TMEDA)Cl2, Pd(TEEDA)Cl2 (where TMEDA = N,N′‐tetramethylethylenediamine, TEEDA = N,N′‐tetraethylethylenediamine), are dependent on the catalyst. Thermoelectric switching properties can be obtained from the siloxane prepared from the coupling reaction of diphenylsilane with 1,4‐naphthoquinone or 1,4‐naphthalenediol using Pd(TMEDA)Cl2 as catalyst. Copyright © 2001 John Wiley & Sons, Ltd.
Study on the thermal stability of heterogeneous nucleation effect of polypropylene nucleated by different nucleating agents
Authors: Mai Kancheng , Wang Kefeng , Han Zhiwu , Zeng Hanmin 
Published: August 2002

AbstractThe thermal stability of the heterogeneous nucleation effect of polypropylene (PP) nucleated with an organic phosphate (A) and two kinds of sorbitol derivatives (B and D) was investigated by DSC multiscanning. For pure PP, the peak temperature of crystallization (T) was little changed with an increasing number of DSC scans, indicating that nucleation of PP is thermally stable. For the PP nucleated with an organic phosphate (PPA), the temperatures at the onset of crystallization (T) and at the completion of crystallization (T); the peak temperature of crystallization (T) and melting (T); and the heat of crystallization (ΔHc) and fusion (ΔHm) of PP are higher than those of pure PP and were little influenced with an increasing number of DSC scans. For PP nucleated with the sorbitol derivatives (PPB and PPD), the T, T, T, and T decreased with an increasing the number of scans. These results indicated that the thermal stability of heterogeneous nucleation effect of the nucleating agent A is higher than that of nucleating agents B and D. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1643–1650, 2002
Polystyrene and polyether polyurethane elastomer blends compatibilized by SMA: Morphology and mechanical properties
Authors: Cassu Silvana Navarro , Maria Isabel Felisberti  
Published: August 2002

AbstractBlends of polystyrene (PS) and the polyether polyurethane elastomer (PU‐et) were prepared by melt mixing using poly(styrene‐co‐maleic anhydride) (SMA) containing 7 wt % of maleic anhydride as a compatibilizer. The polyurethane in the blends was crosslinked using dicumyl peroxide or sulfur. The content of maleic anhydride was varied in the blends through the addition of different SMA amounts. The morphology of the blends was analyzed by SEM and a drastic reduction of both the domain size and its distribution was observed with increase of the anhydride content in the blends. The morphology of the PU‐et blends also showed dependence on the crosslinker agent used for the elastomer, and larger domains were obtained for the elastomer phase crosslinked with dicumyl peroxide. The mechanical properties of the blends were evaluated by flexural and impact strength tests. The blend containing 0.5 wt % of maleic anhydride and 20 wt % of PU‐et crosslinked with sulfur showed the highest strength impact, which was three times superior to the PS strength impact, and the blends containing 20 wt % of PU‐et crosslinked with dicumyl peroxide showed the highest deflection at break independent of the anhydride content. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 830–837, 2002
Photocurable positive photoresist‐comprising copolymers having pendant alkoxy ethyl moieties
Authors: Liu Jui‐Hsiang , Shih Jen‐Chieh 
Published: August 2002

AbstractA series of copolymers based on methacrylic acid (MAA), methyl methacrylate (MMA), n‐butyl methacrylate (BM), and bornyl methacrylate (BMA) with various feed molar ratios were synthesized. To introduce the protecting alkoxy ethyl moieties onto copolymers, the pendant carboxyl groups were further reacted with alkyl vinyl ether. The pendant alkoxy ethyl groups on copolymers could be deprotected by acid catalyst. Characterization of positive‐tone photoresist‐comprising copolymers having pendant alkoxy ethyl groups was carried out. Effects of alicyclic bornyl groups on the sensitivity and thermal properties of copolymers were investigated. It was found that the existence of bornyl groups in polymer might interfere with the hydrogen bonding produced by pendant carboxyl groups, leading to the decrease of thermal resistance. Acid‐catalyzed dehydration crosslinking of pendant carboxyl groups of copolymers was also investigated. The exposure characteristic curves and the lithographic evaluation of the positive‐tone photoresist were all investigated. Effects of alicyclic bornyl groups on the plasma etching resist of copolymers were also evaluated. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 889–897, 2002
Effects of the cure cycle and thermoplastic content on the final properties of dicyanate ester/polysulfone Semi‐IPNS
Authors: Harismendy I. , Del Rio M. , Valea A. , Gavalda Jna. , Mondragon I. 
Published: August 2002

AbstractA bisphenol A dicyanate resin, BADCy, was toughened by incorporating polysulfone, PSU, at various compositions. The catalyst system used was a mixture of copper acetylacetonate and nonylphenol. Phase separation and rheokinetics were studied through curing. The blends seemed to have a LCST behavior, and the presence of PSU did not affect the polycyclotrimerization kinetics. The phase structure, thermal, and mechanical properties of the final network were investigated as a function of the PSU content and cure temperature. The toughness of the BADCy/PSU blends was closely related to their final morphology, increasing with the amount of phase inversion. The mechanical properties were not affected by the addition of the thermoplastic. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1799–1809, 2002
Influences of contents and molecular weights of LDPE on DOP plasticization of PVC
Authors: Shieh Yeong‐Tarng , Liu Chih‐Ming 
Published: August 2002

AbstractInfluences of contents and molecular weights of low‐density polyethylene (LDPE) on dioctyl phthalate (DOP) plasticization in the poly(vinyl chloride) (PVC) plastisol (PVC/DOP/AO = 100/30/6.5) were investigated using DMA and DSC. The plasticization effects of DOP on the PVC plastisol were found to decrease with increasing LDPE content. A negligible plasticization effect of DOP on the PVC plastisol was found when the LDPE content was equal to or higher than 75 parts per 100 parts by weight of LDPE and PVC together. Based on thermal fractionation experiments, a favorable interaction between LDPE and DOP was developed during melt blending of LDPE and the PVC plastisol. The present interaction enabled the incorporation of DOP into LDPE and decreased the plasticization effects of DOP on the PVC plastisol. A further decrease in the plasticization effects of DOP on the PVC plastisol by the presence of LDPE was found with increasing LDPE molecular weights. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2548–2555, 2002
Improvement of properties of silica‐filled natural rubber compounds using polychloroprene
Authors: Choi Sung‐Seen 
Published: August 2002

AbstractBecause silica has strong filler–filler interactions, a silica‐filled rubber compound is characterized by a poor dispersion of the filler. Properties of silica‐filled natural rubber (NR) compounds were improved using polychloroprene (chloroprene rubber [CR]). The bound rubber content of the compound increases and the filler dispersion is also improved by adding CR to the compound. Physical properties such as modulus, tensile strength, abrasion, and crack resistance are improved by adding CR. Elongation at break of the vulcanizates containing CR is longer than that of the vulcanizate without CR, although crosslink density of the former is higher than that of the latter. The improved physical properties are attributed to the good dispersion of silica by adding CR. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2609–2616, 2002
Thermal stabilization of poly(3‐hydroxybutyrate) by poly(glycidyl methacrylate)
Authors: Lee Seung No , Lee Moon Yeon , Park Won Ho 
Published: August 2002

AbstractPoly(3‐hydroxybutyrate) (PHB)/poly(glycidyl methacrylate) (PGMA) blends with the PGMA content up to 30 wt % were prepared by a solution‐precipitation procedure. The thermal decomposition of PHB/PGMA blends was studied by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and differential thermal analysis (DTA). The thermograms of PHB/PGMA blends contained a two‐step degradation process, while that of pure PHB sample exhibited only one‐step degradation process. This degradation behavior of PHB/PGMA blends, which have a higher thermal stability as measured by maximum decomposition temperature or residual weight after isothermal degradation for 1 h, is probably due to crosslinking reactions of the epoxide groups in the PGMA component with the carboxyl chain ends of PHB fragments during the degradation process, and the occurrence of such reactions can be assigned to the exothermic peaks in their DTA thermograms. An isothermal study of these blends at 200–250°C for 1 h indicated that the residual weight was directly correlated with the amount of epoxide groups in the PHB/PGMA blends. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2945–2952, 2002; DOI 10.1002/app.10318
Effects of processing conditions on the curing of a vinyl ester resin
Authors: Abadie M. J. M. , Mekhissi K. , Burchill P. J. 
Published: August 2002

AbstractThe effects of temperature, initiator, and accelerator levels on the curing of an epoxy bisphenol‐A vinyl ester resin Derakane® 411‐45 (formulated with styrene) were investigated by gel‐time and exotherm‐peak measurements on bulk samples. It was observed that the gel time was reduced as the initiator or accelerator ratio increased. Except at higher contents of the accelerator, a small kinetic plateau was seen in the gel curve and a shift of the maximum exotherm toward high temperatures in the DSC curves. This was explained by the dual role played by the accelerator species. A regression analysis of all gel‐time data showed a dependence of 3/2 order in the accelerator and first order in the initiator concentrations. Thus, for this polymerization initiation system, the gel time can be predicted for any initiator and cobalt levels and at any temperature within the ranges studied. The effect of the initiator on the unreacted styrene and vinyl ester was also examined. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1146–1154, 2002; DOI 10.1002/app.10403
Synthesis of block copolyetherether ketones and investigations of their properties
Authors: Ozden S. , Charayev A. M. , Shaov A. H. 
Published: August 2002

AbstractUsing oligoketones with different degrees of condensation (n = 1, 10, 20), dichlorides of isophthalic and terephthalic acids and 2,2‐bis[4‐hydroxyphenyl]‐propane block‐copolyetherether ketones (BCPEEKs) were synthesized by means of acceptor–catalytic polycondensation. Their properties were also investigated. It was shown that BCPEEK possesses good solubility, high molecular weight, and is characterized by high thermal and mechanical properties. The correlation between some properties of the polyethers and the degree of condensation of oligoketones was also investigated. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 485–490, 2002
Cellulose membranes grafted with vinyl monomers in homogeneous system
Authors: Ibrahim Maha M. , Flefel Eman M. , El‐Zawawy Waleed K. 
Published: August 2002

AbstractThe homogeneous grafting of a hydrophilic monomer onto cellulose derivatives was carried out in an aqueous system at 30, 50, 70, and 90°C during reaction periods of 30–180 min. The graft polymer was isolated by ethanol from the reaction mixture, dried, and weighed. The grafted polymer was characterized by the IR method, as well as the microscopic sample morphology detected by scanning electron microscopy. The water absorption capacities and grafting values of the grafted cellulose derivatives were also determined. The maximum grafting yield was obtained at 30°C. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2629–2638, 2002
Characterization of novel biodegradable copolyesters prepared from glycolyzed products of poly(ethylene terephthalate)
Authors: Maeda Yasukatsu , Mori Hajime , Maeda Takuya , Itoh Osamu , Yamaguchi Kazumi , Kubota Shizuo , Nakayama Atsuyoshi , Kawasaki Norioki , Yamamoto Noboru , Aiba Seiich 
Published: August 2002

AbstractPoly(ethylene terephthalate), PET reacted with various glycols in the presence of titanium tetraisopropoxide as a catalyst. The glycolyzed PET was fractionated into two parts—soluble and insoluble in CHCl3—characterized and used as a raw material to synthesize copolyesters. The soluble part in the CHCl3 part was a mixture of monomers and oligomers, and no melting points were observed. On the other hand, in the insoluble part a melting point was determined. The glycolyzed PET and copoly(succinic anhydride/ethylene oxide), PES were condensed to produce copolymers. The synthesized copolyesters were amorphous and hydrolyzed enzymatically due to a decrease in the crystallinity. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1838–1847, 2002; DOI 10.1002/app.10462
The effect of mercapto‐modified EVA on rheological and dynamic mechanical properties of NBR/EVA blends
Authors: Jansen Paulo , Soares Bluma G. 
Published: August 2002

AbstractThe effect of mercapto‐modified ethylene vinyl acetate copolymer (EVALSH) on the rheological and dynamic mechanical properties of acrylonitrile butadiene rubber (NBR) and ethylene vinyl acetate copolymer (EVA) blends was evaluated at different blend compositions. The addition of 5 phr of EVALSH in the blends resulted in an increase of the melt viscosity and a substantial decrease of the extrudate swell ratio. These results can be attributed to the interactions occurring between the double bond of the NBR phase and the mercapto groups along the EVALSH backbone. The power–law index also presents a slight increase in the presence of EVALSH, indicating a decrease in the pseudoplastic nature of the compatibilized blends. The reactive compatibilization of NBR/EVA blends with EVALSH was also confirmed by the decrease of damping values and an increase of glass transition temperature, in dynamic mechanical analysis. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2335–2344, 2002
Morphological studies in thermally initiated emulsion (co)polymerization without conventional initiators
Authors: Du Yong‐Zhong , Ma Guang‐Hui , Ni Hen‐Mei , Nagai Masatoshi , Omi Shinzo 
Published: August 2002

AbstractPoly(methyl methacrylate‐co‐styrene) composite latices were prepared by thermally initiated seed emulsion (co)polymerization of styrene (ST), methyl methacrylate (MMA), or ST and MMA employing a PST or PMMA seed in the absence of conventional initiators. The changes of particle morphology, observed by transmission electron microscopy (TEM), were investigated by varying seed particle component, the weight ratio of monomer to seed polymer, monomer composition, and employing preswelling of the seed particles. The size distribution of polymer particles obtained from thermally initiated emulsion (co)polymerization was improved by employing the seed process. Hemisphere‐like, sandwich‐like, core‐shell, and inverted core‐shell particle morphologies were observed depending upon the polymerization conditions. The preswelling of seed particles did not affect the morphology of final particles. The particle morphologies, obtained from the thermal process, were compared with those obtained from conventional seed emulsion polymerization. The incorporation of an initiator fragment SO to polymer chain ends seemed to allow the PST chains to gain some hydrophilicity. From the observation of particle morphology, the hydrophilicity of involved polymers were in the following order: PMMA with ionic (SO) chain ends > PMMA with no ionic ends > PST with ionic ends > 60% MMA P(MMA‐co‐ST) with no polar ends > 40% MMA P(MMA‐co‐ST) with no polar ends > PST with no polar ends. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1737–1748, 2002; DOI 10.1002/app.10581