bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of a new compatibilizer system on the flexural properties of wood–polyethylene composites
Authors: Geng Y. , Li K. , Simonsen J. 
Published: January 2004

AbstractA novel wood–plastic compatibilizer system containing a paper wet‐strength agent as a wood‐binding domain and stearic anhydride as a polyethylene (PE) binding domain was investigated. Treatment of wood flour with a commercial paper wet‐strength agent Kymene® 557H (simply called Kymene) before the mixing of PE and the wood flour increased the modulus of rupture (MOR) and the modulus of elasticity (MOE) of the resulting wood–PE composites. Addition of stearic acid in the mixing of PE and the wood–Kymene mixture further increased the MOR and MOE. Stearic anhydride was even more effective than stearic acid in the increase of the MOR and MOE. Compared to wood–PE composites without a compatibilizer, the stearic anhydride–Kymene compatibilizer system increased the MOR by about 33% and the MOE by about 40%. The stearic anhydride–Kymene compatibilizer system gave a slightly lower MOR, but higher MOE than those of the commercially used compatibilizer (maleic anhydride‐grafted polypropylene). The compatibilization mechanisms were proposed as follows: Kymene not only bound to wood fibers, but also strengthened and stiffened the wood fibers. Stearic anhydride formed covalent linkages such as ester and amide with the Kymene‐consolidated wood fibers and the long hydrocarbon chain of the stearic anhydride bonded to the PE matrix through entanglements and/or cocrystallization. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3667–3672, 2004
Novel surface modification of high‐density polyethylene films by using enzymatic catalysis
Authors: Zhao Jingchan , Guo Zhian , Ma Xiaoyan , Liang Guozheng , Wang Junlong 
Published: January 2004

AbstractThe surface of high‐density polyethylene (HDPE) films was modified by an enzyme, soybean peroxidase (SBP). The enzymatic surface modification was performed using a peroxidase as catalyst and hydrogen peroxide as oxidizing agent. The chemical composition and morphology of HDPE surfaces were characterized by X‐ray photoelectron spectroscopy, infrared spectroscopy, and scanning electron microscopy. Results showed that after enzymatic treatment, the O/C atomic ratio of HDPE surfaces increased, and new functional groups such as –CO– appeared. Moreover, the surface of treated HDPE films became rougher than untreated surfaces. The hydrophilicity of treated and untreated HDPE films was analyzed by UV–vis spectroscopy and contact angle measurements. The decreased contact angle of the HDPE with water and increased adsorption ability of the surface to a water‐soluble dye clearly indicated that enzymatic treatment can significantly increase the hydrophilicity of the surfaces of HDPE films. The catalytic mechanism of SBP was also discussed. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3673–3678, 2004
Water‐insoluble polymers with ability to remove metal ions
Authors: Rivas Bernabé L. , Villegas Sandra 
Published: January 2004

AbstractCrosslinked poly[3‐(methacryloylamino)propyl]dimethyl(3‐sulfopropyl)ammonium hydroxide‐co‐2‐acrylamido glycolic acid [P(MAAPDSA‐co‐AGCO)] was synthesized by radical polymerization and tested as an adsorbent under competitive and noncompetitive conditions for Cu(II), Cd(II), Hg(II), Zn(II), Pb(II), and Cr(III) by batch and column equilibrium procedures. The resin–metal ion equilibrium was achieved before 1 h. The resin showed a maximum retention capacity value for Hg(II) at pH 2 of 1.084 meq/g. The recovery of the resin was investigated at 20°C under different concentrations of HNO3 and HClO4. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3679–3685, 2004
Constrained shrinkage of highly oriented poly(methyl methacrylate) fibers
Authors: Wright Debra D. , Lautenschlager Eugene P. , Gilbert Jeremy L. 
Published: January 2004

AbstractConstrained shrinkage of fibers is the primary method used to examine orientation in amorphous materials. During the test, fibers are constrained, heated, and the stress that develops is measured as a function of time and temperature. This article describes an apparatus developed to measure that stress and a series of experiments for melt‐spun poly(methyl methacrylate) fibers fabricated under three conditions: (1) constant viscosity, (2) increasing temperature, and (3) increasing draw velocity. Results show that both the rates of rise and the decay of the fiber shrinkage stress have an Arrhenius relationship with temperature. Fibers fabricated at a constant viscosity have the same maximum shrinkage stress and rate of stress decay. As the processing temperature decreases or as draw velocity increases, for other parameters held constant, the maximum shrinkage stress increases. The rate of stress rise increases with decreasing processing temperature or increasing draw velocity. Maximum shrinkage stress also increases with increasing molecular orientation when measured by a different test, free heat‐induced shrinkage of the fibers. However, it was not possible to correlate both of these results to rubber elasticity theory attributed to the high degree of orientation present in the fibers and high polydispersity in the starting material. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 4047–4056, 2004
Preparation of membranes by electropolymerization of pyrrole functionalized by a ferrocene group
Authors: Naji A. , Cretin M. , Persin M. , Sarrazin J. 
Published: January 2004

AbstractThe preparation of dense membranes by the electropolymerization of functionalized pyrrole (Py) by ferrocene units was carried out. The synthesis of N‐[3‐(pyrrol‐1‐yl)propyl]ferrocene‐1‐carboxamide (or [(ferrocenyl)amidopropyl] pyrrole, FAPP) is described. The electropolymerization of the monomer on platinum electrode and on stainless‐steel meshes was studied. The electroactivity of the grafted ferrocenyl group of the FAPP monomer was confirmed and the electrochemical properties of the electrogenerated FAPP film were investigated. The stability in potentiostatic and potentiodynamic modes of FAPP films was low and, to improve the latter, the electrochemical preparation of the copolymer between the pyrrole and the FAPP was performed. The electrochemical characterization of the copolymer showed that it was possible to control the oxidation state of both electroactive compounds of the film. The FAPP/Py copolymer was then prepared on stainless‐steel meshes to produce membranes, whose transport properties were electrochemically controllable. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3947–3958, 2004
Effects of EPDM and wollastonite on structure of isotactic polypropylene blends and composites
Authors: Šmit Ivan , Musil Vojko , Švab Iztok 
Published: January 2004

AbstractPolypropylene blends and composites with 5, 10, and 15 vol % of EPDM and 2, 4, and 6 vol % of untreated and treated wollastonite filler were examined by applying different techniques. Elastomeric ethylene/propylene/diene terpolymer (EPDM) component and wollastonite influenced the crystallization process of isotactic polypropylene (iPP) matrix in different ways. The nucleation of hexagonal β‐iPP, the increase of overall degree of crystallinity, and crystallite size of iPP were more strongly affected by wollastonite than the addition of EPDM was. Both ingredients also differently influenced the orientation of α‐form crystals in iPP matrix. Wollastonite increased the number of a*‐axis‐oriented α‐iPP lamellae plan parallel to the sample surface, whereas the addition of EPDM reoriented the lamellae. The orientation parameters of ternary composites exhibited intermediate values between those for binary systems because of the effects of both components. EPDM elastomer considerably affected well‐developed spherulitization of iPP, increasing the spherulite size. Contrary to EPDM, because of nucleating ability or crystal habit, wollastonite caused significantly smaller iPP spherulites. Small spherulites in ternary iPP/EPDM/wollastonite composites indicated that the wollastonite filler (even in smallest amounts) exclusively determined the morphology of ternary composites. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 4072–4081, 2004
Reactive blends of polyamide 6 with polyester elastomer using coupling agents
Authors: Kim Byung Kyu , Baek Sang Hyun , Kim Min Soo 
Published: January 2004

AbstractIn situ compatibilized melt blends of polyamide 6 (PA‐6) with polyester elastomer (PEL) were prepared in a corotating twin‐screw extruder using two types of coupling agent (CA): diglycidyl ether of bisphenol A (DGEBA) and 1,4‐phenylene bis(2‐oxazoline) (PBO). The notched impact strength of PA‐6 and PA‐6/PEL blends increased with the addition of coupling agent, especially DGEBA, and the maximum impact toughening of the blend was obtained with 0.6 mol % DGEBA, the composition of minimum domain size observed from SEM. Viscosities of the untreated blends increased over those of the base resins at low frequencies. Viscosities of both the base resins and the blends increased with the addition of CA, and the effect was much more pronounced with DGEBA, especially for PA‐6 and PA‐6–rich blends. The crystallization temperature (Tc) of PEL increased over 10°C, whereas the Tc of PA‐6 decreased by 2–3°C in the blends. With the addition of coupling agents, the crystallization melting temperature (Tm) and Tc of PA‐6 decreased by up to 5°C with DGEBA, implying that the crystallization of PA‐6 is disturbed by the in situ formed PA‐6–CA–PEL or PA‐6–CA–PA‐6 type copolymer. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3966–3973, 2004
Polyacrylonitrile‐g‐poly(vinyl alcohol) membranes for the pervaporation separation of dimethyl formamide and water mixtures
Authors: Kurkuri Mahaveer D. , Aminabhavi Tejraj M. 
Published: January 2004

AbstractPoly(vinyl alcohol) as well as its grafted copolymer membranes with polyacrylonitrile (PAN‐g‐PVA) were prepared and used to separate water and dimethyl formamide mixtures by the pervaporation technique. The three following membranes were prepared: (1) pure PVA; (2) 46% grafted PAN‐g‐PVA; and (3) 93% grafted PAN‐g‐PVA. Pervaporation separation experiments were carried out at 25°C for the feed mixture containing 10 to 90% water. By use of the transport data, permeation flux, separation selectivity, swelling index, and diffusion coefficients have been calculated. By increasing the grafting of the membrane, flux decreased, whereas separation selectivity increased slightly over that of pure PVA membrane. Arrhenius activation parameters for transport processes were calculated for 10 mass % water containing feed mixture by using flux and diffusion data obtained at 25, 35, and 45°C. Transport parameters were discussed in terms of sorption‐diffusion principles. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 4091–4097, 2004
Newsprint paper waste as a fiber reinforcement in rubber composites
Authors: Nashar D. E. El. , Abd‐El‐Messieh S. L. , Basta A. H. 
Published: January 2004

AbstractThe investigation of the economical use of lignocellulose waste, which is one of the environmental problems facing third‐world nations, is ongoing. In this study, we intended to increase the use of newsprint fibers in the rubber industry. For this reason, we treated newsprint fibers with sodium silicate and magnesium chloride, and we examined the water retention values and thermal degradation analyses of the treated fiber waste. The activation energy of degradation was evaluated with the Coats–Redfern method of analysis. The effects of the addition of different amounts [0–60 parts per hundred parts of rubber by weight (phr)] of untreated and treated newsprint fibers on both the electrical and mechanical properties of two different types of rubber (natural rubber and acrylonitrile rubber) were studied. This study led us to the conclusion that the addition of treated newsprint fiber waste at a concentration of 40 phr could lead to an end product characterized by good electrical and mechanical properties. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3410–3420, 2004
Evidence that intrauterine and postnatal androgens affect the development of pyloric stenosis
Authors: James William H. 
Published: January 2004

AbstractBACKGROUNDIt is rather well established that the causal antecedents of pyloric stenosis (PS) contain both genetic and environmental factors. However, in spite of substantial quantities of epidemiological data, no widespread environmental causal agent has yet been established. There have been recent extensions of our knowledge of the endocrine consequences of fetal growth restriction and of the endocrine determinants of sex ratio. It seemed worth reviewing the epidemiological data on PS in the light of these new developments to see whether this would provide a basis for a plausible hypothesis on these suspected environmental causes of PS.METHODS AND RESULTSThe search terms “pyloric stenosis” and (“epidemiology” or “risk factors”) were combined on the Ovid Medline data base for the years 1966 onwards. The data from the resulting papers were augmented by notes occasioned by almost daily reading at the Library of the Royal Society of Medicine (London) for the past 25 years. (Electronic data retrieval systems do not access incidentally recorded data such as sib sex ratios).CONCLUSIONSIt is hypothesized that high intrauterine and early postnatal androgen levels constitute an environmental cause of PS. Birth Defects Research (Part A) 67:000–000, 2003. © 2003 Wiley‐Liss, Inc.
Sex ratio and associated risk factors for 50 congenital anomaly types: Clues for causal heterogeneity
Authors: Rittler Monica , López‐Camelo Jorge , Castilla Eduardo E. 
Published: January 2004

AbstractBACKGROUNDSex ratio (SR) deviations have been reported for many congenital anomalies, but so far no satisfactory explanation for these deviations has been found. The aim of this study was to detect sex‐related differences in the association between risk factors and congenital anomalies, and to relate these differences with possibly underlying causes of birth defects.METHODSBetween 1982 and 1999, 1,444,646 newborn infants were examined by the Estudio Colaborativo Latino Americano de Malformaciones Congénitas (ECLAMC) network of South American maternity hospitals. Male relative risks were established for 39,425 infants with 50 selected single anomalies. Associations between male sex and risk factors were identified in nonmalformed infants. In malformed infants, sex‐related risk differences were established, and the SR of these infants, with and without associated risk factors, were compared.RESULTSInfants with neural tube defects (NTDs) and intrauterine growth restriction had a lower SR than those with normal growth, while spina bifida without hydrocephaly (SB[sHy]) was the only NTD subtype without a significant female predominance. Multigravidity lowered the SR of SB(sHy) and HPP (HPP) cases. Increased paternal age inverted the SR of cleft lip (CL) with or without cleft palate (CL[P]) cases from male to female.CONCLUSIONSThe results indicate etiological differences between high and low SB, a stronger relationship between multigravidity and female sex of the offspring than between multigravidity and a specific congenital anomaly, and a possible involvement of dominant mutations for CL(P), as suggested by the association with increased paternal age. Birth Defects Research (Part A) 67:000–000, 2003. © 2003 Wiley‐Liss, Inc.
Mature ovarian cystic teratoma with a highly differentiated homunculus: A case report
Authors: Kuno Naohiko , Kadomatsu Kenji , Nakamura Makoto , Miwa‐Fukuchi Takahiko , Hirabayashi Norio , Ishizuka Takao 
Published: January 2004

AbstractBACKGROUNDMature ovarian cystic teratomas, which are commonly observed benign ovarian tumors, consist of ectodermal, mesodermal, and endodermal components that are generally disorganized. In this report, we document a case in which the solid portion of an ovarian teratoma demonstrated considerable differentiation, forming a doll‐like structure.CASEA 25‐year‐old virginal Japanese woman underwent surgery for an ovarian tumor that was diagnosed as a mature teratoma. A solid mass within the tumor was found to have a head, trunk, and extremities. Consequently, this mass was diagnosed as a mature fetiform teratoma (homunculus). Brain, eye, spinal nerve, ear, teeth, thyroid gland, bone, bone marrow, gut, trachea, blood vessels, and phallic cavernous tissue were confirmed microscopically. Distinctive features were the clear anterior‐posterior, ventral‐dorsal, and left‐right axes, with a spatially well‐organized arrangement of the organs. An eye was located on the front of the head, a spinal nerve lay dorsal to the spinal bones, the thyroid gland was anterior to the trachea, and the gut was deep inside the trunk.CONCLUSIONSThese findings indicate that the information necessary for organization of the body plan may be conserved and transmitted, even with parthenogenesis. Mature cystic teratomas of the ovary are mostly benign and do not always attract detailed attention. However, precise analyses of such tumors may significantly enhance our understanding of both parthenogenetic and normal human development. Birth Defects Research (Part A), 2003. © 2003 Wiley‐Liss, Inc.
Immunostimulation by complete Freund's adjuvant, granulocyte macrophage colony‐stimulating factor, or interferon‐γ reduces severity of diabetic embryopathy in ICR mice
Authors: Punareewattana Korawuth , Holladay Steven D. 
Published: January 2004

AbstractBACKGROUNDIncreased risk of fetal malformation is a complication occurring in pregnant women with type 1 diabetes. Local (uterine) immune stimulation has been shown to reduce diabetes‐induced teratogenesis in mice. Limited information is available regarding the ability of diverse methods of maternal immune stimulation to cause this effect or regarding timing requirements of the immune stimulation.METHODSDiabetes was induced in pregnant ICR mice by streptozocin (STZ) injection. Three different techniques of maternal immune stimulation, complete Freund's adjuvant (CFA), granulocyte‐macrophage colony‐stimulating factor (GM‐CSF), or interferon‐γ (IFN‐γ), were then used to stimulate the immune system of the mice.RESULTSApproximately 50% of fetuses from hyperglycemic (>26 mM/liter blood glucose) dams were malformed, with neural tube defects predominating. Maternal immune stimulation during the time of normoglycemia, i.e., prior to the onset of hyperglycemia, was necessary to reduce teratogenic effects associated with hyperglycemia for each of the immune stimulants. The immune‐stimulated diabetic mice then produced significantly lower and approximately equal numbers of malformed fetuses: CFA 20.9%, GM‐CSF 23.3%, and IFN‐γ 13.9%.CONCLUSIONSThese results suggest that mechanistically diverse forms of nonspecific immune activation result in protection against diabetes‐related teratogenesis, but only if given prior to onset of hyperglycemia. Birth Defects Research (Part A) 67:000–000, 2003. © 2003 Wiley‐Liss, Inc.
A self‐priming microfluidic diaphragm pump capable of recirculation fabricated by combining soft lithography and traditional machining
Authors: Sin Aaron , Reardon Christopher F. , Shuler Michael L. 
Published: January 2004

AbstractFluid transport is crucial in the development of microanalytical devices. While there are many micropump designs available, most are incapable of sustaining recirculation of fluid at μL/min to mL/min levels. We have designed and fabricated a positive displacement micropump by combining soft lithography with traditional bulk machining. The micropump is actuated through pneumatic pressure. The pump is self‐priming and is suitable for recirculating fluid through a microfluidic device containing mammalian cell culture. By custom designing the volume of the pumping chamber, tight control of the output flow rate can be obtained by changing the actuation frequency. It can also be fabricated easily on plastic substrates without access to expensive microfabrication equipment. © 2004 Wiley Periodicals, Inc.
Expression of recombinant vitellogenin in the yeast Pichia pastoris
Authors: Ding J.L. , Lim E.H. , Li H.F. , Kumar J.K. , Lee S.L. , Lam T.J. 
Published: January 2004

AbstractVitellogenin (Vtg) plays vital roles as precursor to the yolk proteins and as carrier for lipids, carbohydrates, phosphates, metal ions, vitamins, and hormones into the oocytes during the massive deposition of yolk nutrients for subsequent nourishment of the developing embryos. Reproductive success is highly sensitive to the nutritional quality of the broodstock diet, which greatly affects the egg and larval viability. We present a novel strategy for genetically engineering a Pichia pastoris yeast strain that constitutively produces recombinant Vtg (rVtg), for application as an enriched feed. The tilapia Oreochromis aureus Vtg (OaVtg) cDNA (5.3 kb) was cloned into a nonsecretory pGAPZA vector. Clones containing up to 31 copies of glyceraldehyde‐3‐phosphate dehydrogenase (GAP)‐promoter‐driven Vtg expression cassettes were isolated. These clones expressed a membrane‐associated intracellular rVtg protein of 194 kDa, constituting up to 1.16% of total protein. To facilitate future purification of rVtg, we explored the possibility of secreting rVtg using the native Vtg secretion signal and the α‐factor secretion signal of Saccharomyces cerevisiae. However, neither signal promoted the secretion of rVtg. The clones maximally expressed rVtg at 23°C, reaching a peak at 22 h in shake flasks and 16 h in a fermentor. The clones exhibited a significant increase in essential amino acids and long‐chain polyunsaturated fatty acids, which are important for its application as a high‐quality nutrient feed. © 2004 Wiley Periodicals, Inc.
Resistance to signal activation governs design features of the MAP kinase signaling module
Authors: Chapman Stephen , Asthagiri Anand R. 
Published: January 2004

AbstractGiven its broad influence over numerous cell functions, redesigning the mitogen‐activated protein (MAP) kinase signaling module would offer a powerful means to engineer cell behavior. Early challenges include identifying quantitative module features most relevant to biological function and developing simple design rules to predictably modify these features. This computational study delineates how features such as signal amplification, input potency, and dynamic range of output may be tuned by manipulating chief module components. Importantly, the model construction identifies a metric of resistance to signal activation that quantitatively predicts module features and design trade‐offs for broad perturbations in kinase and phosphatase expression. Its predictive utility extends to dynamic properties such as signal lifetime, which often dictates MAP kinase effect on cell function. Taken together, we propose that predictably altering MAP kinase signaling by tuning resistance is not only a feasible engineering strategy, but also one exploited by natural systems to allow each MAP kinase to exert pleiotropic effects in a context‐dependent manner. External stimuli not only activate kinases, but also alter phosphatase expression and activity, thereby reconfiguring a single module for quantitatively distinct modes of signaling such as transient vs. sustained dynamics, each with unique effects on cell function. © 2004 Wiley Periodicals, Inc.