bluuebunny/crossref_metadata_2025_split huggingface dataset:
Detection of Yersinia pestis DNA in two early medieval skeletal finds from Aschheim (Upper Bavaria, 6th century A.D.)
Authors: Wiechmann Ingrid , Grupe Gisela 
Published: June 2004

AbstractIn the course of a molecular genetic investigation of a double inhumation, presumably a mother/child burial from Aschheim (Upper Bavaria, 6th century A.D.), which included analysis of mitochondrial DNA, molecular sexing, and polymorphic nuclear DNA, Yersinia pestis‐specific DNA was detected. Molecular analyses were performed on DNA extracts obtained from two teeth of one skeleton and four teeth of the other. The use of the primer pair YP12D/YP11R (Raoult et al. [2000] Proc. Natl. Acad. Sci. 97:12800–12803), able to amplify part of the Y. pestis plasmid pPCP1 pla sequence, resulted in amplification products of the expected fragment size. Using BLASTN 2.2.2, the sequences of these amplification products shared 100% identity with that of the modern Y. pestis pla sequence in GenBank, with the exception of one amplification product which revealed a single base substitution. The application of a “suicide PCR” with the independent primer pair YP11D/YP10R (Raoult et al. [2000] Proc. Natl. Acad. Sci. 97:12800–12803) resulted in amplification products which shared a 96–98% homology with that of the modern Y. pestis pla sequence in GenBank. The observed deviations were presumably due to miscoding lesions in the template DNA. No modern Y. pestis DNA was introduced into the institute, and thus no positive controls were carried along. All extraction and PCR controls remained negative. The identification of Y. pestis‐specific DNA sequences in these two skeletons, buried in the second half of the 6th century A.D., constitutes molecularly supported evidence for the presence of Y. pestis, the causative agent of plague, during the first pandemic recorded. Am J Phys Anthropol, 2004. © 2004 Wiley‐Liss, Inc.
Brief communication: Discrimination between European‐American and African‐American children based on deciduous dental metrics and morphology
Authors: Lease Loren R. , Sciulli Paul W. 
Published: June 2004

AbstractThis study employs metric and morphological features of the deciduous dentition for discriminating between European‐American and African‐American children and providing allocation rules (regression equations). Five logistic regression equations are presented, with the percentage of correct allocation to group of between 90.1–92.6%. All five equations employ three metric traits (the mesiodistal diameters of the mandibular deciduous canines and anterior and posterior deciduous premolars) and one morphological feature (cusp number of the maxillary deciduous anterior premolar). In addition to these four variables, only two or three additional morphological features are added in carious combinations in the final equations. Correct allocation to group is 4–12% greater when combining metric and morphological features compared to using the features separately. Am J Phys Anthropol, 2004. © 2004 Wiley‐Liss, Inc.
Physical growth and nutritional status of Tsimane' Amerindian children of lowland Bolivia
Authors: Foster Z. , Byron E. , Reyes‐García V. , Huanca T. , Vadez V. , Apaza L. , Pérez E. , Tanner S. , Gutierrez Y. , Sandstrom B. , Yakhedts A. , Osborn C. , Godoy R.A. , Leonard W.R. 
Published: June 2004

AbstractThis study examines patterns of growth and nutritional status of indigenous Tsimane' children under 9 years of age (n = 199 boys and 210 girls), based on a cross‐sectional sample from 58 villages from the Beni Deparment of lowland Bolivia. Compared with US children, Tsimane' children are quite short, with linear growth tracking at or below the US 5th centile in both sexes. The prevalence of low height‐for‐age (“stunting;” HA Z‐scores ≤−2) is 52% in boys and 43% in girls. In contrast, weight‐for‐height in Tsimane' children approximates the US median, with the prevalence of low weight‐for‐height (“wasting”; WH Z‐scores ≤−2) being only 4% and 6% in boys and girls, respectively. Tsimane' boys and girls are leaner than their US peers, but their levels of body fatness are not so low as to indicate severe energy stress. Arm muscularity of Tsimane' children is similar to that of their US age peers, and this suggests that they are not experiencing acute protein malnutrition. Variation in measures of nutritional status of Tsimane' children is modestly correlated with village‐level differences. Degree of isolation, as measured by distance to urban centers or to primary forest, was not a strong predictor of children's anthropometric status. Rather, in both boys and girls, nutritional status was most strongly associated with number of teachers in the village, a measure of access to education. Comparative analyses indicate that high levels of statural growth stunting are common among indigenous populations throughout lowland South America. This problem appears to be largely attributable to poor dietary quality (diets low in key micronutrients) and high disease loads. Further research is needed to identify the specific causes and potential interventions for the high rates of childhood growth stunting in this region. Am J Phys Anthropol 126:343–351, 2005. © 2004 Wiley‐Liss, Inc.
N2O Reduction by the μ4‐Sulfide‐Bridged Tetranuclear CuZ Cluster Active Site
Authors: Chen Peng , Gorelsky Serge I. , Ghosh Somdatta , Solomon Edward I. 
Published: June 2004

AbstractNitrous oxide (N2O) reduction is a chemical challenge both in the selective oxidation of organic substrates by N2O and in the removal of N2O as a green‐house gas. The reduction of N2O is thermodynamically favorable but kinetically inert, and requires activating transition‐metal centers. In biological systems, N2O reduction is the last step in the denitrification process of the bacterial nitrogen cycle and is accomplished by the enzyme nitrous oxide reductase, whose active site consists of a μ4‐sulfide‐bridged tetranuclear CuZ cluster which has many unusual spectroscopic features. Recent studies have developed a detailed electronic‐structure description of the resting CuZ cluster, determined its catalytically relevant state, and provided insight into the role of this tetranuclear copper cluster in N2O activation and reduction.
Synthesis and characterization of ultraviolet‐curable fluorinated polydimethylsiloxanes as ultraviolet‐transparent coatings for optical fiber gratings
Authors: Colomines GaëL , Andre Sébastien , Andrieu Xavier , Rousseau Alain , Boutevin Bernard 
Published: June 2004

AbstractSynthesis of photocrosslinkable fluorinated polydimethylsiloxane (PDMS) was carried out through the direct hydrosilylation of allyl 2‐(perfluorohexyl)ethyl ether with copoly(dimethyl methyl hydro siloxane). The hydrosilylation of the fluorinated allyl ether allowed the introduction of fluorinated groups onto the polysiloxane backbone. Then, a second hydrosilylation of allyl methacrylate led to PDMS bearing both fluorinated and photocrosslinkable groups. The ratio between fluorinated groups and allyl methacrylate groups allowed us to tune the refractive index of the resin without changing thermal properties. Formulations containing fluorinated PDMS were ultraviolet‐cured, and their ultraviolet transparency and Yttrium Aluminium Garnet (YAG) laser resistance were investigated. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2021–2026, 2003
Syntheses of chemical‐modified cellulose obtained from waste pulp
Authors: Hadano Shingo , Onimura Kenjiro , Tsutsumi Hiromori , Yamasaki Hirohito , Oishi Tsutomu 
Published: June 2004

AbstractChemical‐modified pulps were synthesized from four types of waste pulps (Pulp1–4) and succinic anhydride (SAn) or maleic anhydride (MAn). The solubility of the modified pulps was evaluated in common organic solvents, and their thermal properties were investigated by DSC measurement. The solubility of the modified pulps increased with an increasing degree of substitution (DS). However, no Tg or Tm of these modified pulps was confirmed. Pulps and modified pulps were graft‐polymerized with ε‐caprolactone (CL) in bulk and in DMAc/LiCl. Although the solubility of the graft copolymers was similar to modified pulps, some graft copolymers showed a Tg by the introduction of CL units. In the bulk, graft copolymers obtained from modified pulps and nonmodified pulps showed a Tg of about 75°C and no Tg, respectively. In DMAc/LiCl, the obtained graft copolymers from both modified and nonmodified pulps exhibited a Tg of 95–110°C. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2059–2065, 2003
Effect of filler treatment and crosslinking on mechanical and dynamic mechanical properties and electrical conductivity of carbon black‐filled ethylene–vinyl acetate copolymer composites
Authors: Das N. C. , Chaki T. K. , Khastgir D. 
Published: June 2004

AbstractMechanical, dynamic mechanical, and electrical conductivity of conductive carbon black‐filled ethylene–vinyl acetate (EVA; 28% VA) composites were investigated. The above‐mentioned properties were also measured when carbon black was treated with nitric acid before addition to the EVA matrix. It was found that acid‐treated carbon black exhibits a higher filler–polymer interaction and this was reflected in the improvement of the mechanical properties and the modification of electrical conductivity of these composites, especially when measured against the temperature. The effect of curing of the polymer matrix on the mechanical properties and electrical conductivity was also investigated. It was found that the introduction of crosslinks in the polymer matrix improves its mechanical properties as well as the thermal stability of its electrical conductivity. The electrical conductivity of ethylene propylene diene (EPDM) and an EVA–EPDM (50/50) blend filled with carbon black were also studied for comparison. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2073–2082, 2003
Studies on polyacrylates containing pendant ligand with carbonyl and hydroxyl functions and their divalent metal complexes
Authors: Kaliyappan T. , Rajagopan S. , Kannan P. 
Published: June 2004

AbstractA series of monomers were prepared by reacting (meth)acryloyl chloride with 2,4‐dihydroxybenzophenone, 2,4‐dihydroxybenzaldehyde, and 2,4‐dihydroxyacetophenone, respectively. The monomers were polymerized in dimethylformamide (DMF) at 70°C using benzoyl peroxide as an initiator. Polymer–metal complexes were obtained from DMF solutions of polymers with an aqueous solution of metal ions. The polymers and polymer–metal complexes were characterized by elemental analysis and spectral studies. The IR spectra of these complexes suggest that the metals are coordinated through the oxygen of the carbonyl group and the oxygen of the phenolic–OH group. The electronic spectra, electron paramagnetic resonance (EPR) spectra, and magnetic moments of polychelates showed an octahedral and square planar structure for Ni(II) and Cu(II) complexes, respectively. X‐ray diffraction studies revealed that polychelates are highly crystalline. The thermal and electrical properties, catalytic activity, and structure–property relationships are discussed. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2083–2090, 2003
Polymer‐immobilized cyclodextrin trapping of model organic pollutants in flowing water streams
Authors: Orprecio Ricardo , Evans Christopher H. 
Published: June 2004

AbstractEpichlorohydrin‐crosslinked β‐cyclodextrin polymers (BCDPs) were prepared and characterized by Fourier transform infrared. Beads of the BCDPs were used to pack a column for trapping organic contaminants in flowing water (flow rate = 5–32 mL/min). The contaminants were naphthalene (a model for polyaromatic hydrocarbons), naproxen (a model for pollutants of pharmaceutical origin), and 2‐naphthol (a model for pesticides with pH‐dependent ionization states). The trapping efficiencies were determined with fluorescence spectroscopy as the analytical technique. The best trapping efficiencies were obtained for BCDPs with a nominal cyclodextrin/epichlorohydrin ratio of 1:29. Trapping was highly efficient for naphthalene (98%) and 2‐naphthol (70%), but it was much less efficient for naproxen (18%). Possible causes for these differences were examined. The trapped organics could be flushed from the column with an ethanol wash. The recovery of the organics with this approach was very good (>95%). This simple column design, made of inexpensive and reusable materials, has potential applications in water remediation and water sampling. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2103–2110, 2003
High‐density polyethylene foams. I. Polymer and foam characterization
Authors: Zhang Yaolin , Rodrigue Denis , Ait‐Kadi Abdellatif 
Published: June 2004

AbstractThe density and morphology of closed‐cell high‐density foams were investigated with four different molecular weights of high‐density polyethylene (HDPE). The characterization of polyethylene via rheological methods was used to determine its influence on foam density and morphology. We found that foaming grade decreased with increasing molecular weight and increased with blowing agent content. The average cell size was also a strong function of molecular weight and blowing agent content. Increasing both the molecular weight and amount of blowing agent decreased the cell size. Cell size also increased for our lowest molecular weight HDPE but decreased for the others. Cell density also increased with increasing HDPE molecular weight. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2111–2119, 2003
Isothermal phase diagrams and phase‐inversion behavior of poly(vinylidene fluoride)/solvents/additives/water systems
Authors: Yeow M. L. , Liu Y. T. , Li K. 
Published: June 2004

AbstractIsothermal ternary phase diagrams of poly(vinylidene fluoride) (PVDF)/solvents/nonsolvent systems were produced using four different solvents, N,N‐dimethylacetamide (DMAc), 1‐methyl‐2‐pyrrolidinone (NMP), N,N‐dimethylformamide (DMF), and triethyl phosphate (TEP), and using water as a nonsolvent. The effects of the additives polyvinylpyrrolidone (PVP, Mw = 10,000), ethanol, and lithium perchlorate (LiClO4) on the phase‐inversion behavior of PVDF/DMAc/water ternary system were investigated, with additive concentrations of 2 and 6 wt %, at temperatures of 25 and 70°C, respectively. Ethanol, glycerol, and water were used to study the cloud points of 10, 15, and 20 wt % PVDF/DMAc concentrations, at solution temperatures ranging from 30 to 70°C. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2150–2155, 2003
Effect of mica addition on the properties of natural rubber and polybutadiene rubber vulcanizates
Authors: Castro Daniele F. , Suarez João Carlos Miguez , Nunes Regina C. R. , Visconte Leila L. Y. 
Published: June 2004

AbstractThe rheometric, mechanical, and dynamic mechanical properties as well as fracture surfaces of natural rubber–mica and polybutadiene rubber–mica vulcanizates were studied. Mica was used in the range of 0–30 phr and the rheometric study was carried out at 160°C. The results indicate that the mechanical properties are improved as filler addition increases. Dynamic mechanical testing was used to analyze the observed mechanical behavior. The two elastomers showed different fracture behaviors. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2156–2162, 2003
Electrochemical preparation of soluble sulfonated polymers and aniline copolymers of aniline sulfonic acids in dimethylsulfoxide
Authors: Şahin Yücel , Pekmez Kadir , Yıldız Attila 
Published: June 2004

AbstractFully sulfonated polyaniline was produced during the electrochemical polymerization of orthanilic, metanilic, and sulfanilic acids in dimethylsulfoxide (DMSO). The dry conductivity values of the polymers obtained from the above three isomers of aminobenzene sulfonic acids were found to be 0.052, 0.087, and 0.009 S/cm, respectively. Furthermore, partially sulfonated copolymers of these aniline sulfonic acids and aniline were also synthesized electrochemically in DMSO. The dry conductivity values of the copolymers obtained from these three acids were found to be 0.094, 0.26, and 0.033 S/cm, respectively. The polymers and copolymers are soluble in water, DMSO, and N‐methyl‐2‐pyrrolidone. The structure and properties of these polymers and copolymers were elucidated using cyclic voltammetry, scanning electron microscopy, Fourier transform infrared, elemental analysis, and ultraviolet‐visible absorption spectroscopy. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2163–2169, 2003
Durable antimicrobial nylon 66 fabrics: Ionic interactions with quaternary ammonium salts
Authors: Son Young‐A , Sun Gang 
Published: June 2004

AbstractAcidic or basic dyeing of fibers involves ionic interactions between reactive groups on the polymers and dye molecules. Such interactions can be utilized in the functional finishing of fabrics. This article discusses a new approach of employing the ionic interactions between anionic carboxylic end groups of polyamides and cationic quaternary ammonium salts in the chemical finishing of nylon fabrics to achieve desired durable antimicrobial functions. The finishing conditions such as pH, finishing temperature, and time were studied, and the pH of the finishing bath was very critical in affecting the ionic interactions and thus exhaustion of the salts on the fabrics. The finishing process should be carried out at a temperature above the glass transition temperature of nylon 66. The finished products demonstrated excellent durability of antimicrobial functions. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2194–2199, 2003
Synthesis and characterization of poly(ester urethane)/nitrokonjac glucomannan semi‐interpenetrating polymer networks
Authors: Gao Shanjun , Zhang Lina , Cao Jinli 
Published: June 2004

AbstractWe prepared novel semi‐interpenetrating polymer network (semi‐IPN) materials by mixing poly(ester urethane), synthesized by the polymerization reaction between poly(ethylene glycol adipate) and toluene diisocyanate in the presence of 2,2‐bis(hydroxyl methyl) propionic acid as an extender, with nitrokonjac glucomannan (NKGM) in tetrahydrofuran and then by crosslinking and curing the mixture at 60°C for 1.5 h. Miscibility and the properties of the sheets were studied by Fourier transition infrared spectroscopy, wide‐angle X‐ray diffraction, differential scanning calorimetry (DSC), and scanning electron microscopy. The results indicate that strong interactions between poly(ester urethane) and NKGM in the semi‐IPN sheets occurred, leading to good miscibility between the two polymers in the whole region of component ratios. When the content of NKGM was 10%, the tensile strength and breaking elongation of the semi‐IPN sheet were simultaneously enhanced to 35 MPa and 960%, respectively, compared with pure polyurethane. The DSC curves showed a low softening temperature for the poly(ester urethane), which resulted in the high elongation. By changing the NKGM amount from 10 to 90%, we prepared a series of composite materials from an elastomer to tough plastics. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2224–2228, 2003
Effects of the chirality and functionality of monomers on the holographic gratings formed in photosensitive films
Authors: Liu Jui‐Hsiang , Wu Fuh‐Tsang 
Published: June 2004

AbstractPhotosensitive holographic polymer films were fabricated. Instead of liquid crystals, a nonreactive high‐refractive‐index diphenyl sulfide was mixed with several monomers and an initiator for the preparation of the holographic grating films. To investigate the formation of periodic arrays of the photosensitive refractive‐index modulation films and the effects of the chirality and functionality of monomers on the diffraction efficiency, chiral monomeric (−)‐bornyl acrylate, (+)‐bornyl acrylate, and the racemate (±)‐bornyl acrylate were synthesized and copolymerized with various multifunctional monomers. A reasonable schematic of the photosensitive polymerization mechanism was proposed. The effects of the multifunctional monomers, initiator concentrations, and feed monomer concentrations on the diffraction efficiencies were investigated. The morphologies of the polymer matrices were studied with scanning electron microscopy. Pictures of real light diffraction patterns with 15 grating points were obtained. In comparison with those described in the literature, the diffraction efficiency obtained in this investigation was relatively high. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2246–2254, 2003
Preparation, characterization, and nanostructural evolution of epoxy nanocomposites
Authors: Chen Chenggang , Curliss David 
Published: June 2004

AbstractEpoxy nanocomposites were prepared from the different organoclays with aerospace epoxy resin. A series of organoclays treated with alkylammonium chloride with different alkyl groups of different carbon chains were prepared, including SC4, SC6, SC8, SC10, SC12, SC16, SC18, and NC8, NC12, NC18. All of these organoclays, except for SC4, are very compatible with the aerospace Epon 862/curing agent W. The characterization from wide‐angle X‐ray diffraction (WAXD), small‐angle X‐ray scattering (SAXS), and transmission electron microscopy (TEM) confirms the exfoliated nanostructure. The six‐carbon chain length of the ammonium cation is enough to wet the surface of the clay gallery to make the organoclay compatible with epoxy resin. The clay with lower cation exchange capacity is more favorable for the polymer penetration inside the gallery and is dispersed better in the polymer matrix. The structural evolution of the aerospace epoxy nanocomposite was monitored by in situ SAXS. The 3% SC18/Epon 862/W, 3 and 6% SC8/Epon 862/W showed exfoliated nanostructure, while there is no exfoliation taking place for 3% S30B/Epon 862/W and 3%S25A/Epon 862/W up to 200°C. The acidity from the pendent group in SC18 and SC8 has a catalytic effect for the polymerization inside the gallery, while the organic pendent group of S30B and S25A does not. The faster reaction of the intragallery epoxy resin produced extra thermal heat inside the gallery to expand the gallery and is favorable for the migration of epoxy resin outside the gallery into the gallery where exfoliation took place. The exothermal heat of curing inside the gallery is an important factor for nanosheets exfoliation. Although exfoliation took place for both 3% SC18/Epon 862/W and 3% SC8/Epon 862/W, the detailed morphology development during the curing is different. For 3% SC8/Epon 862/W, the interplanar spacing between the layers is increased gradually, while 3% SC18/Epon 862/W experienced the disappearance of the ordered structure of the layered silicate in the beginning of the curing process and reappearance of the ordered structure of the silicate later. The glassy and rubbery moduli of the polymer‐silicate nanocomposites were found to be greater than the unmodified resin because of the high aspect ratio and high stiffness of the layered silicate filler. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2276–2287, 2003