bluuebunny/crossref_metadata_2025 huggingface dataset:
Preparation and characterization of bismaleimide‐modified bisphenol dicyanate epoxy matrices
Authors: Dinakaran K. , Suresh Kumar R. , Alagar M.
Published: September 2003

An intercrosslinked network of epoxy matrix systems modified by cyanate ester (CE) and bismaleimide (BMI) was developed. Epoxy systems modified with 4%, 8%, and 12% (by weight) cyanate ester were made by using epoxy resin and cyanate ester, with diaminodiphenylmethane as the curing agent. The reaction between the cyanate ester and the epoxy resin during the cure process of cyanate ester–modified epoxy systems was studied using Fourier transform infrared spectroscopy. The cyanate ester–toughened epoxy systems were further modified with 4%, 8%, and 12% (by weight) bismaleimide (N,N′‐bismaleimido‐4,4′‐diphenylmethane). BMI–CE–Epoxy matrices were characterized using differential scanning calorimetry (DSC), thermogravimetric analysis, and heat deflection temperature analysis. The matrices, in the form of castings, were characterized for their mechanical properties such as tensile strength, flexural strength, and unnotched Izod impact test as per ASTM methods. Mechanical studies indicated that the introduction of cyanate ester into epoxy resin improved the toughness and flexural strength, with a reduction in tensile strength and glass‐transition temperature, whereas the incorporation of bismaleimide into epoxy resin influenced the mechanical and thermal properties according to its percentage content. However, the introduction of both cyanate ester and bismaleimide influenced the mechanical properties according to their percentage content. DSC thermograms of cyanate ester–modified epoxy and BMI‐modified epoxy showed unimodal reaction exotherms. The thermal degradation temperature and heat distortion temperature of the cured BMI‐modified epoxy and CE‐epoxy systems increased with increasing bismaleimide content. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1596–1603, 2003
Effect of alkali treatment on properties of the lignocellulose fabric Hildegardia
Authors: Rajulu A. Varada , Meng Y. Z. , Li X. H. , Rao G. Babu , Devi L. Ganga , Raju K. Mohana , Reddy R. Ramakrishna
Published: September 2003

The uniaxial natural fabric from the tree Hildegardia populifolia was treated with 5% aqueous NaOH solution for 0, 2, 4, 6, and 8 h, and the resulting changes were analyzed by density, Fourier infrared spectroscopic, X‐ray, polarized microscopic, and scanning electron microscopic techniques. On alkali treatment, absorption of water and elimination of hemicellulose in the fabric were observed. In each case, the tensile strength, modulus, and percent elongation at break were determined. The tensile strength, modulus, and density were found to be maximum at 4 h of alkali treatment. Hemicellulose was found on the surface of the untreated fabric. After 6 and 8 h of alkali treatment, some microcracks developed in the fabric. The area of the void region in the fabric increased with the duration of alkali treatment. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1604–1608, 2003
Additive diffusion from LDPE slabs into contacting solvents as a function of solvent absorption
Authors: Helmroth I. E. , Dekker M. , Hankemeier Th.
Published: September 2003

This article describes the simultaneous diffusion of a migrant and a solvent in low density polyethylene (LDPE). The migrant (Irganox 1076) moves out of the slab, while the solvent (isooctane, n‐heptane or cyclohexane) moves inwards. Solvent absorption was measured separately by following the increase of the mass of the slab in time. It can be described by the Fick diffusion equation with a diffusivity depending on the solvent concentration, and an interface concentration depending on time. The final absorptions were 12% for isooctane, 14% for n‐heptane, and 29%for cyclohexane. Additive concentrations in the slab were determined at different positions by microtoming. Experiments were done for several contacting times. The concentration profiles were strongly affected by the solvent. A larger local solvent concentration increases the diffusivity of the migrant. The Fick equation with a migrant diffusivity depending on the solvent concentration gives a good description for the results with isooctane and n‐heptane. The description is less good for the measurements with cyclohexane (when the polymer swells strongly). © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1609–1617, 2003
Wettability enhancement of polystyrene with electron cyclotron resonance plasma with argon
Authors: Guruvenket S. , Komath Manoj , Vijayalakshmi S. P. , Raichur A. M. , Mohan Rao G.
Published: September 2003

Polystyrene cell‐culture substrates were treated with argon glow discharge to make their surfaces hydrophilic. The process was novel in that it used a microwave electron cyclotron resonance (ECR) source for polymer surface modification. The substrates were processed at different microwave powers and time periods, and the surface modification was assessed with by measurement of the water contact angle. A decrease in contact angle was observed with increasing microwave power and processing time. Beyond a certain limit of power and duration of exposure, however, surface deterioration occurred. The optimum conditions for making the surfaces hydrophilic without deterioration of the samples were identified. The plasma parameters were assessed by Langmuir probe measurement. Fourier transform infrared spectroscopy with attenuated total reflectance showed evidence for the induction of hydrophilicity on the surface. The surface micromorphology was examined with scanning electron microscopy. The results prove that the ECR glow discharge was an efficient method for enhancing the wettability of the polymer surfaces. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1618–1623, 2003
Water‐soluble/dispersible cationic pressure‐sensitive adhesives. I. Adhesives from solution polymerization
Authors: Yan Zegui , Deng Yulin
Published: September 2003

Pressure‐sensitive adhesives (PSAs) have long been a problem as sticky contaminants for paper recycling mills. The main problem associated with such stickies is that the PSAs in the waste papers deposit on the felts, press rolls, and drying cylinders of paper machines, and this creates problems with paper formation, reducing the paper quality and paper machine runnability. The annual cost of stickies to the U.S. paper industry is estimated to be about $600,000,000–650,000,000. To solve this problem, a series of cationic water‐soluble/dispersible PSAs have been synthesized by the free‐radical solution polymerization of butyl acrylate and [3‐(methacryloylamino)propyl]trimethylammonium chloride in ethanol. The PSA end‐use properties, repulpability in paper recycling, and the effects on the properties of recycled paper products have been studied. The cationic PSAs can be dissolved or dispersed in water if the cationic charge density in the PSA backbone is controlled, and so they do not deposit as stickies during recycling and papermaking processes. Because the PSAs are cationically charged, they can easily be removed from the papermaking system by adsorption onto the negatively charged fibers and fine surfaces. Furthermore, the adsorbed colloidal or dissolved PSAs have little effect on the final paper properties. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1624–1630, 2003
Mechanochemical surface activation of ground tire rubber by solid‐state devulcanization and grafting
Authors: Cavalieri F. , Padella F. , Cataldo F.
Published: September 2003

Cured rubber powder was successfully devulcanized under the application of high‐energy ball milling. An attempt was made to improve the efficiency of devulcanization with a phenolic antioxidant (2,6‐di‐tert‐butyl‐4‐methyl‐phenol). In addition, the grafting of virgin natural rubber to the surface of rubber powder was promoted by milling under an inert atmosphere. The extent of mechanochemical devulcanization was studied by estimation of the sol–gel fractions and crosslink densities. Our findings suggest that the process led to a preferential breakage of sulfur crosslinks. The curing behavior of the compounds and the mechanical properties of the vulcanizates containing treated rubber powder and fresh rubber were investigated. The chemical and mechanical properties depended strongly on the experimental milling conditions, which could consequently be controlled to improve the quality of the reclaimed rubber. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1631–1638, 2003
Thermal and mechanical properties of a polypropylene nanocomposite
Authors: Ellis Thomas S. , D'Angelo Joseph S.
Published: September 2003

An experimental polypropylene (PP) nanocomposite, containing approximately 4 wt % of an organophilic montmorillonite clay, was prepared and characterized, and its properties were compared with those of talc‐filled (20–40 wt %) compositions. Weight reduction, with maintained or even improved flexural and tensile moduli, especially at temperatures up to 70°C, was a major driving force behind this work. By a comparison with the analytical data from a nylon 6 (PA‐6) nanocomposite, it was found that the PP nanocomposite contained well‐dispersed, intercalated clay particles; however, X‐ray diffraction, transmission electron microscopy, dynamic mechanical analysis, and permeability measurements confirmed that exfoliation of the clay in PP was largely absent. The increased glass‐transition temperature (Tg) of a PA‐6 nanocomposite, which possessed fully exfoliated particles, indicated the molecular character of the matrix–particle interaction, whereas the PP nanocomposite exhibited simple matrix–filler interactions with no increase in Tg. The PP nanocomposite exhibited a weight reduction of approximately 12% in comparison with the 20% talc‐filled PP, while maintaining comparable stiffness. Undoubtedly, considerable advantages may be available if a fully exfoliated PP nanocomposite is fabricated; however, with the materials available, a combination of talc, or alternative reinforcements, and nanocomposite filler particles may provide optimum performance. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1639–1647, 2003
Kinetic study of radical polymerization. II. Solid‐state bulk polymerization of sodium methacrylate by differential scanning calorimetry
Authors: Mahdavian Ali‐Reza , Zandi Mojgan
Published: September 2003

The solid‐state radical polymerization of sodium methacrylate was investigated. It was initiated by azobisisobutyronitrile, which was used as a radical initiator. Differential scanning calorimetry (DSC) was used to observe the endothermic and exothermic transitions during the polymerization reaction. Structural studies were performed with the DSC thermograms and Fourier transform infrared and ultraviolet–visible spectra, and all of the results confirmed the progress of the reaction. The obtained data revealed that the polymerization reaction proceeded completely with a 100% conversion. ΔH of this reaction was calculated with various amounts of the initiator, and the peak temperatures were determined at different heating rates. The activation energy (19.7 kcal mol−1) was also obtained by the Kissinger method for this type of solid polymerization reaction. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1648–1654, 2003
Influence of molecular weight on the domain coarsening rates in linear polyethylene–poly(ethylene‐co‐1‐octene) blends
Authors: Phochalam Noree , Tabtiang Arunee , Venables Richard A.
Published: September 2003

The coarsening rates of the two‐phase morphologies of linear polyethylene/poly(ethylene‐co‐1‐octene) blends were determined as functions of molecular weight. Samples with cocontinuous morphologies that were prepared through solution blending were annealed in the melt state for various times, and, subsequently the length scales of the morphologies were determined with a line‐intersection method. Length‐scale data were multiplied by a function that normalized for the effects of differences in zero‐shear‐rate viscosity and thermal energy; after normalization, the data largely fell on one trend line within the bounds of experimental error. This indicated that the principal effect of increasing molecular weight was to slow the coarsening rate through an increase in melt viscosity, with little effect from the thermodynamic compatibility of the two polymers. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1655–1661, 2003
Crosslinking of cotton cellulose in the presence of alkyl diallyl ammonium salts. I. Physical properties and agent distribution
Authors: Chen Jui‐Chin , Yeh Jen‐Taut , Chen Cheng‐Chi
Published: September 2003

We used three kinds of alkyl diallyl ammonium salts (methyl, ethyl, and propyl) in combination with dimethyloldihydroxyethyleneurea (DMDHEU) as crosslinking agents. The nitrogen content, dry crease recovery angle (DCRA), moisture regain, and wicking height for the DMDHEU/alkyl diallyl ammonium salts were in the order of CH3 > C2H5 > C3H7, but the wet crease recovery angle (WCRA) and tensile strength retention (TSR) were in the opposite order at the same resin concentration. For the same DCRA and TSR, the WCRA values for only DMDHEU were lower than those for DMDHEU/alkyl diallyl ammonium salts, and the WCRA values for DMDHEU/alkyl diallyl ammonium salts were in the order of C3H7 > C2H5 > CH3. Both the OH group of the cellulose and DMDHEU could react with the vinyl or epoxy groups of the alkyl diallyl ammonium salts during the pad–dry–cure process. The surface migration for DMDHEU/alkyl diallyl ammonium salts was in the order of CH3 > C2H5 > C3H7. Fabrics treated with DMDHEU/alkyl diallyl ammonium salts showed good antibacterial properties. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1662–1669, 2003
Microhardness of styrene/butadiene block copolymer systems: Influence of molecular architecture
Authors: Michler G. H. , Baltá‐Calleja F. J. , Puente I. , Cagiao M. E. , Knoll K. , Henning S. , Adhikari R.
Published: September 2003

The influence of molecular architecture on the mechanical properties of styrene/butadiene block copolymers was investigated by means of the microhardness technique. It was found that the microhardness of the styrene/butadiene block copolymers is dictated by the nature of microphase separated morphology. In contrast to polymer blends and random copolymers, in which the microhardness generally follows the additivity rule, the behavior of the investigated block copolymers was found to significantly deviate depending on their molecular architecture. The glass‐transition temperature of the polystyrene phase (Tg‐PS), which practically remained constant and that of the polybutadiene phase (Tg‐PB), which varied with the change in the block copolymer architecture, apparently do not influence the microhardness values of the block copolymers. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1670–1677, 2003
Curing behavior of a novolac‐type phenolic resin analyzed by differential scanning calorimetry
Authors: De Medeiros Eliton S. , Agnelli José A. M. , Joseph Kuruvilla , De Carvalho Laura H. , Mattoso Luiz H. C.
Published: September 2003

Curing of a novolac‐type phenolic resin was studied by DSC. The kinetic analysis was performed by means of the dynamic Ozawa method at heating rates of 5, 10, 15, and 20°C/min. This analysis was used to determine the kinetic parameters of the curing process. The activation energy was found to be 144 kJ/mol. It was found that the Ozawa exponent values decreased with increasing reaction temperature from 3.5 to 1, suggesting a change in the reaction mechanism from microgel growth to diffusion‐controlled reaction. The reaction rate constant was found to range from 123.0 to 33.6 (°C/min)n. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1678–1682, 2003
Thermoreversible hydrogels. XIX. Synthesis and swelling behavior and drug release behavior for the N‐isopropylacrylamide/poly(ethylene glycol) methylether acrylate copolymeric hydrogels
Authors: Lee Wen‐Fu , Lin Yu‐Hung
Published: September 2003

A series of thermosensitive copolymeric hydrogels were prepared from various molar ratios of N‐isopropylacrylamide (NIPAAm) and poly(ethylene glycol) methylether acrylate (PEGMEAn), which was synthesized from acryloyl chloride and poly(ethylene glycol) mono methylether with three oxyethylene chain lengths. Investigation of the effect of the chain length of oxyethylene in PEGMEAn, and the amount of the PEGMEAn in the NIPAAm/PEGMEAn copolymeric gels, on swelling behavior in deionized water was the main purpose of this study. Results showed that the swelling ratio for the present copolymeric gels increased with increasing chain length of oxyethylene in PEGMEAn and also increased with increase in the amount of PEGMEAn in the copolymeric gels. However, the gel strength and effective crosslinking density of these gels decreased with increase in swelling ratio. Some kinetic parameters were also evaluated in this study. Finally, the drug release and drug delivery behavior for these gels were also assessed. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1683–1691, 2003
Synthesis and thermal properties of polystyrene/montmorillonite nanocomposites by γ‐ray radiation polymerization
Authors: Zhang Wei‐An , Shen Xiao‐Feng , Liu Ming‐Fei , Fang Yue‐E
Published: September 2003

Polystyrene/montmorillonite nanocomposites were prepared by γ‐ray radiation polymerization. X‐ray diffraction and high‐resolution transmission electron microscopy confirmed that polystyrene (PS) could be easily inserted between the sheets of montmorillonite (MMT) to form intercalated nanocomposites. In these PS/MMT nanocomposites, the distance between the sheets of MMT was barely influenced by varying the content of the MMT. Thermal stabilities of the samples were studied by thermal gravimetric analysis and differential scanning calorimetry. The glass‐transition temperature of PS/MMT nanocomposites was obviously higher than that of the pure PS. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1692–1696, 2003
The “cold‐solutioning” phenomenon in cellulose triacetate–acetone mixtures
Authors: Variankaval N. E. , Rezac M. E. , Abhiraman A. S.
Published: September 2003

Direct mixing of cellulose triacetate (CTA) in acetone at room temperature produces only an opaque swollen gel at all concentrations. However, cycling the mixture between room temperature and −78 ± 3°C results in a stable solution at room temperature, if the concentration is less than 6% (w/w). This process has been called “cold‐solutioning.” Such a process also produces a clear solution at concentrations between 6% (w/w) and 10% (w/w); however, in time, the solution separates slowly into at least two phases, a clear liquid and an opaque gel phase. At concentrations above 10% (w/w) and below 20% (w/w), the system exhibits two phases. A completely opaque swollen gel forms at concentrations of 20% (w/w) and above. The above‐described cold‐solutioning phenomena are shown to be the coupled kinetic and thermodynamic consequences of (1) the large thermal stresses that would result from thawing a swollen mixture of CTA and acetone, arising from the large differences in their thermal expansion coefficients; and (2) the “bimodal” composition of the cellulose derivative. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1697–1707, 2003
Effect of Ni(II), Cd(II), and Cu(II) metal ions on the crystallinity of poly(maleic anhydride‐alt‐acrylic acid)
Authors: Kavlak Serap , Kaplan Can Hatice , Güner Ali , Rzaev Zakir
Published: September 2003

The chelation of poly(maleic anhydride‐alt‐acrylic acid) [poly(MA‐alt‐AA)] with nickel (II), cadmium (II), and copper (II) ions was carried out under various pH conditions. Polychelates were prepared by precipitation from the aqueous solutions of metal salts at different pH values. The effects of metal salts (NiCl2·6H2O, CdCl2·2H2O, CuCl2·2H2O) on the degree of crystallinity of poly(MA‐alt‐AA) were investigated by X‐ray diffraction spectroscopy at different pH values. The degree of crystallinity was found to be in the following order: Cd(II)–polychelate > Cu(II)–polychelate > Ni(II)–polychelate at pH 6.36; this result was also supported by gravimetric studies. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1708–1715, 2003
Tensile modulus modeling of carbon‐filled nylon 6,6 and polycarbonate‐based resins
Authors: Konell Jeremiah P. , King Julia A. , Miskioglu Ibrahim
Published: September 2003

Electrically and thermally conductive resins can be produced by adding conductive fillers to insulating polymers. Mechanical properties, such as tensile modulus, are also important. This research focused on performing compounding runs followed by injection molding and tensile testing of carbon‐filled nylon 6,6 and polycarbonate‐based resins. The three carbon fillers investigated included an electrically conductive carbon black, synthetic graphite particles, and a milled pitch–based carbon fiber. For each polymer, resins were produced and tested that contained varying amounts of these single‐carbon fillers. In addition, combinations of fillers were investigated by conducting a full 23 factorial design and a complete replicate in each polymer. These tensile modulus experimental results were then compared to results predicted by several different models. For the composites containing only one filler type, the Nielsen model with the modified Ψ term provided the best prediction of the actual experimental values. For the composites containing more than one filler type, a new parameter, which includes the vibrated bulk density (VBD) of the fillers, was incorporated into the Nielsen model with the modified Ψ term. This model with the new VBD parameter provided the best estimate of experimental tensile modulus for composites containing multiple‐filler types. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1716–1728, 2003
Characterization of the free volume in high‐impact polystyrene/polypropylene and high‐impact polystyrene/high‐density polyethylene blends probed by positron annihilation spectroscopy
Authors: Hu Youhua , Qi Chenze , Liu Weiming , Wang Baoyi , Zheng Houtian , Sun Xudong , Zheng Xiaoming
Published: September 2003

The free‐volume properties of high‐impact polystyrene (HIPS)/polypropylene (PP) and HIPS/high‐density polyethylene (HDPE) blends were investigated by means of positron annihilation lifetime spectroscopy (PALS). The measured results show that the free‐volume holes in the semicrystalline polymers, such as PP and HDPE, were not large enough to accommodate the branched chains and the end groups of the macromolecular chains in HIPS to produce favorable interactions between the semicrystalline polymers and the HIPS polymer in these blends; thus immiscible blends were formed. The weak interaction between two dissimilar polymer molecules only took place in the regions between two amorphous phases. In addition, the observed negative deviations of the longest lifetime intensity and the free‐volume fraction were attributed to the influence of the interfacial polarization during PALS measurement. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1507–1514, 2003
Effect of humidified feeds on oxygen permeability of mixed matrix membranes
Authors: Moore Theodore T. , Vo Trinh , Mahajan Rajiv , Kulkarni Sudhir , Hasse Dave , Koros William J.
Published: September 2003

Hybrid inorganic/organic membranes, often called mixed matrix membranes, are composed of (inorganic) molecular sieves dispersed in a continuous (organic) polymer matrix. Recent studies have demonstrated that mixed matrix membranes have the potential to exceed the performance of conventional polymer membranes while maintaining their processability. Because water vapor can be present in air and in natural gas feeds, it is an ideal candidate for studying the effects of strongly sorbing minor components on mixed matrix membranes. Water vapor has been shown to cause complex but predictable effects on mixed matrix materials. In this article simple models are proposed to describe the behavior of mixed matrix membranes with humidified feeds to assist in interpreting observed performance. This research has shown that mixed matrix membranes composed of zeolite 4A dispersed in poly(vinyl acetate) are adversely affected by water adsorbed in the pores of zeolite 4A. On the other hand, a novel, more hydrophobic molecular sieve, SSZ‐13, appears to be an ideal candidate for mixed matrix membranes because it has improved transport properties over zeolite 4A and is less affected by sorbed water. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1574–1580, 2003
Reticular groove and reticulum are innervated by myenteric neurons with different neurochemical codes
Authors: Pfannkuche Helga , Schellhorn Corinna , Schemann Michael , Gäbel Gotthold
Published: September 2003

The reticulum and the reticular groove are functional distinct compartments within the ovine forestomach. While the reticulum takes part in various motor functions, such as mixing, retaining, and rejecting the forestomach ingesta, the reticular groove serves mainly as a bypass between the esophagus and the abomasum. To accomplish these different tasks, the compartments develop specific motility patterns that are controlled by intrinsic neural circuits. In this study the intrinsic innervation by myenteric neurons was analyzed by quadruple immunohistochemistry against cholineacetyl transferase (ChAT), nitric oxide synthase (NOS), substance P (SP), and vasoactive intestinal peptide (VIP). Four neurochemically different subpopulations of myenteric neurons were found in the reticulum and the floor of the reticular groove: ChAT/–, ChAT/SP, NOS/–, and NOS/VIP. The neuronal proportions were calculated relative to all myenteric neurons. Neurons of the reticulum were mostly immunoreactive for ChAT (89% ± 3%), whereas neurons adjacent to the reticular groove predominantly expressed a nitrergic phenotype (62% ± 4%). ChAT‐positive neurons were also immunoreactive for SP (ChAT/SP: 64% ± 3% reticulum; 25% ± 1% reticular groove) or were purely cholinergic (ChAT/–: 25% ± 4% reticulum; 13% ± 3% reticular groove). NOS‐positive neurons colocalized VIP (NOS/VIP: 10% ± 3% reticulum; 46% ± 1% reticular groove) or none of the other neurotransmitters (NOS/–: 1% ± 1% reticulum; 17% ± 3% reticular groove). Analysis of the soma sizes revealed that in both compartments the nitrergic neurons were significantly larger than the cholinergic neurons. It is suggested that the specific neurochemical code in combination with a specific morphology leads to a precise regulation of the specialized tasks of the reticulum and reticular groove by subpopulations of myenteric neurons. Anat Rec Part A 274A:917–922, 2003. © 2003 Wiley‐Liss, Inc.
CD40 and CD40L expression in the chicken embryo aorta: Possible role in the endothelial–mesenchymal transdifferentiation process
Authors: Arciniegas Enrique , Becerra Aniuska , de Sanctis Juan B. , Graterol Armando , Ramírez Richard
Published: September 2003

Endothelial–mesenchymal transdifferentiation (EMT) is believed to play a crucial role in embryonic vascular development and intimal thickening, which contributes to the pathogenesis of atherosclerotic lesions. However, the mechanisms by which it occurs, as well as the signals that control it, have not yet been elucidated. Given the important role played by the CD40‐CD40 ligand (CD40L) system during the initiation and progress of atherosclerosis, we investigated whether both CD40 and CD40L were present in the aortic wall during EMT and the advanced stages of chicken embryo development. CD40‐CD40L expression was found on endothelial cells (ECs), mesenchymal cells, and smooth muscle cells (SMCs) at all stages examined, and appeared to be distributed across the aortic wall. However, some notable differences between the expression patterns were observed. CD40 had a more restricted distribution compared to CD40L, and did not stain every cell type of the aortic wall. According to immunoblotting and enzyme‐linked immunosorbent assay (ELISA) analyses, the CD40L content was highest at day 7 of development. An important and novel finding was the expression of CD40L in areas where ECs transdifferentiate into mesenchymal cells. Specifically, CD40L was associated to the surface of cells that were detaching and migrating from the monolayer of ECs, whereas for CD40 a very diffuse subcellular localization was seen at the monolayer and the detaching and migrating cells. These data suggest a possible role for CD40‐CD40L interactions during EMT and the remodeling of the aorta. Anat Rec Part A 274A:942–951, 2003. © 2003 Wiley‐Liss, Inc.
Expression of estrogen receptor α (ERα) in the rat temporomandibular joint
Authors: Yamada Kazuho , Nozawa‐Inoue Kayoko , Kawano Yoshiro , Kohno Shoji , Amizuka Norio , Iwanaga Toshihiko , Maeda Takeyasu
Published: September 2003

Numerous epidemiological studies have pointed out a higher frequency of temporomandibular disorder (TMD) in women than in men, which indicates the involvement of a sex hormone, such as estrogen, in the pathogenesis of TMD. Although estrogen is known to play pivotal roles in osteoarthrosis or rheumatoid arthritis in systemic joints, there have been few reports about the role of estrogen in the temporomandibular joint (TMJ). The effect of estrogen is generally mediated by the estrogen receptors (ERs) ERα (the predominant type) and ERβ. In this study we examined the expression of ERα protein and mRNA in the TMJ of adult male rats by immunocytochemistry and in situ hybridization histochemistry. Intense ERα immunoreactivity was localized in the synovial lining cells, stromal cells in the articular disc, and chondrocytes in the TMJ. These ERα‐immunopositive synovial lining cells are characteristic of cytoplasmic processes identified with confocal and immunoelectron microscopy, which indicates that they are synovial type B cells. In situ hybridization histochemistry confirmed intense signals for ERα in the synovial lining cells and the sublining fibroblasts at mRNA levels. The nuclei of chondrocytes showed an intense immunoreaction for ERα in the maturative and hypertrophic layers of the articular cartilage. In addition to the nuclear localization of ERα, a weak immunoreaction appeared in the cytoplasm of some ERα‐positive cells. These findings support the hypothesis that TMJ tissue—at least in the male rat—has the potential to be an estrogen target tissue. Anat Rec Part A 274A:934–941, 2003. © 2003 Wiley‐Liss, Inc.
Distribution of glycoconjugates during cochlea development in mice: Light microscopic lectin study
Authors: Rueda Joaquin , Cantos Raquel , Lim David J.
Published: September 2003

During development, different epithelial cells in the mouse cochlea express different cell surface glycoconjugates, which may reflect membrane specialization. Some of the lectins tested in this study (SBA, succ‐WGA, and PSA) labeled the sensory cells of the cochlea around birth. Other lectins (WGA, Con A, RCA‐II, and PHA‐E) labeled surfaces of the sensory cells, particularly the stereocilia, from early stages of development (gestation day (GD) 16) through 21 days after birth. These may be adhesion molecules needed to attach the newly forming tectorial membrane (TM) to the stereocilia. Lectin staining of the developing TM revealed that the substructures of the TM are biochemically distinct. Lectin staining also showed the temporal sequence of the expression of cytoplasmic glycoconjugates of the cochlear epithelium during development. Biochemical changes during development are probably the result of different cells being involved in the production of glycoconjugates, and may have functional significance, specifically with regard to the expression of adhesion and/or signaling molecules. Anat Rec Part A 274A:923–933, 2003. © 2003 Wiley‐Liss, Inc.
Growth and maturation of cardiac myocytes in fetal sheep in the second half of gestation
Authors: Burrell Judith H. , Boyn Adrian M. , Kumarasamy Vasumathy , Hsieh Albert , Head Stewart I. , Lumbers Eugenie R.
Published: September 2003

Right (RVFW) and left (LVFW) ventricular free wall cardiac myocytes were collected from 25 fetal sheep aged 77–146 days gestation (term = 150 days gestation), six saline‐infused catheterized fetal sheep (129 GD), and five lambs to measure gestational changes in uni‐ and binucleated cardiac myocyte numbers and cell volumes by confocal microscopy. At 77 days gestation, 2% of the myocytes were binucleated, which increased to 50% at 135 days gestation and 90% at 4–6 weeks after birth. RVFW uni‐ and binucleated myocytes were larger than those in the LVFW, and cell volumes of RVFW uni‐ and binucleated and LVFW binucleated myocytes (but not LVFW uninucleated myocytes) increased with gestation. Before birth, the approximate number of myocytes was greater in the LVFW than in the RVFW (P < 0.001). Before 110 GD, cardiac growth appeared to be due to myocyte hyperplasia, as approximate myocyte numbers and VFW weight increased at the same rate. After 110 days gestation, the approximate myocyte number/g VFW weight decreased, which suggests that myocyte hypertrophy, as well as hyperplasia, was occurring in association with the appearance of a greater proportion of binucleated cells after that time. By 4–6 weeks of age, there was marked hypertrophy of myocytes and an apparent reduction in myocyte number. Anat Rec Part A 274A:952–961, 2003. © 2003 Wiley‐Liss, Inc.
Morphologic characterization of green fluorescent protein in embryonic, neonatal, and adult transgenic rats
Authors: Takeuchi Koichi , Sereemaspun Amornpan , Inagaki Takeshi , Hakamata Yoji , Kaneko Takashi , Murakami Takashi , Takahashi Masafumi , Kobayashi Eiji , Ookawara Shigeo
Published: September 2003

Transgenic (Tg) animals with reporter genes are useful models in which to study cell lineage and the process of differentiation into tissues. We developed the green fluorescent protein (GFP)‐Tg rat, which is more suitable for transplantation and stem cell research because it is larger than mice. We found that marker gene expression was dependent on each organ and developmental stage. In this study we describe GFP expression in various tissues from embryonic, neonatal, and adult animals. GFP expression in brain, lung, liver, and islet tissues was restricted to early developmental stages, but it was continuously strong in the exocrine pancreas, kidney, and cardiac and skeletal muscles. The CAG promoter that was presumed to induce ubiquitous protein expression might be responsible for the differences in expression. Anat Rec Part A 274A:883–886, 2003. © 2003 Wiley‐Liss, Inc.
Rescue of coronal suture fusion using transforming growth factor‐beta 3 (Tgf‐β3) in rabbits with delayed‐onset craniosynostosis
Authors: Lyn Chong Sherri , Mitchell Ronal , Moursi Amr M. , Winnard Phillip , Wolfgang Losken H. , Bradley James , Ozerdem Omer R. , Azari Kodi , Acarturk Oguz , Opperman Lynne A. , Siegel Michael I. , Mooney Mark P.
Published: September 2003

Craniosynostosis results in cranial deformities and increased intracranial pressure, which pose extensive and recurrent surgical management problems. Developmental studies in rodents have shown that low levels of transforming growth factor‐β3 (Tgf‐β3) are associated with normal fusion of the interfrontal (IF) suture, and that Tgf‐β3 prevents IF suture fusion in a dose‐dependent fashion. The present study was designed to test the hypothesis that Tgf‐β3 can also prevent or “rescue” fusing sutures in a rabbit model with familial craniosynostosis. One hundred coronal sutures from 50 rabbits with delayed‐onset, coronal suture synostosis were examined in the present study. The rabbits were divided into five groups of 10 rabbits each: 1) sham controls, 2) bovine serum albumin (BSA, 500 ng) low‐dose protein controls, 3) low‐dose Tgf‐β3 (500 ng), 4) high‐dose BSA (1,000 ng) controls, and 5) high‐dose Tgf‐β3 (1,000 ng). At 10 days of age, radiopaque amalgam markers were implanted in all of the rabbits on either side of the coronal suture to monitor sutural growth. At 25 days of age, the BSA or Tgf‐β3 was combined with a slow‐absorbing collagen vehicle and injected subperiosteally above the coronal suture. Radiographic results revealed that high‐dose Tgf‐β3 rabbits had significantly greater (P < 0.05) coronal suture marker separation than the other groups. Histomorphometric analysis revealed that high‐dose Tgf‐β3 rabbits also had patent coronal sutures and significantly (P < 0.01) greater sutural widths and areas than the other groups. The results suggest that there is a dose‐dependent effect of TGF‐β3 on suture morphology and area in these rabbits, and that the manipulation of such growth factors may have clinical applications in the treatment of craniosynostosis. Anat Rec Part A 274A:962–971, 2003. © 2003 Wiley‐Liss, Inc.
Average bioequivalence of generic clarithromycin tablets in healthy thai male volunteers
Authors: Lohitnavy Ornrat , Lohitnavy Manupat , Sareekan Kannika , Polnok Sanglar , Taytiwat Prawit
Published: September 2003

The objective of this study was to assess bioequivalence of 500‐mg clarithromycin tablets in 24 healthy volunteers. In a randomized, single dose, fasting state, two‐period, crossover study design with a 1‐week washout period, each subject received a 500‐mg clarithromycin tablet. Plasma samples were collected over a 24‐h period after administration and were analyzed by using a validated method using high performance liquid chromatography (HPLC) with electrochemical detection. The time to reach the maximal concentration (tmax,h), the peak concentration (Cmax,ng/ml) and the area under the curve (AUC0–∞,ng h/ml) of the Reference and Test formulations were 2.1±0.7 vs 2.1±0.7, 2474±702 vs 2559±744 and 15803±6120 vs 17683±6650, respectively. Relative bioavailability was 1.12. The 90% confidence interval (90% CI) of Cmax and AUC0–∞ were 95.6–110.8% and 3.5–122.0%, respectively. Bioequivalence between the test and reference preparation can be concluded. Copyright © 2003 John Wiley & Sons, Ltd.
Bioavailability of modified‐release methylphenidate: influence of high‐fat breakfast when administered intact and when capsule content sprinkled on applesauce
Authors: Lee Lucy , Kepple Joanne , Wang Yibin , Freestone Stephen , Bakhtiar Ray , Wang Yanfeng , Hossain Mohammad
Published: September 2003

Ritalin®, an immediate release form of racemic methylphenidate hydrochloride, has been available in the USA since 1955 and is used for the treatment of ADHD. The objective of this study was to evaluate the pharmacokinetics of modified‐release methylphenidate (highest single dose), Ritalin® LA, when administered under fasting condition, with a high‐fat breakfast, and when sprinkled on applesauce in healthy adult subjects. Blood samples were drawn for 24 h following a 40 mg oral administration. Most subjects appeared to produce a bimodal methylphenidate plasma concentration profile. In all three treatment groups, methylphenidate was rapidly absorbed with an initial average tmax(0–4) of 1.3–2.4 h and an average peak plasma concentration [Cmax(abs)] of 14.4–15.2 ng/ml. On average, both the rate [Cmax(abs) and tmax(abs)] and the extent of absorption (AUC0–∞) of methylphenidate were similar when the capsule was given with a high fat breakfast and when the capsule contents were sprinkled onto applesauce, compared with the fasting state. No dose dumping was observed when the capsule was given with a high fat breakfast or when sprinkled onto applesauce. The dose was safe and generally well tolerated. Coadministration of a single oral dose of 40 mg methylphenidate capsule whether administered intact with a high‐fat breakfast or sprinkled on applesauce did not affect the overall rate or extent of absorption of methylphenidate compared with the fasted condition. Copyright © 2003 John Wiley & Sons, Ltd.
Bioequivalence evaluation of two brands of furosemide 40mg tablets (Salurin and Lasix) in healthy human volunteers
Authors: Najib Naji , Idkaidek Nasir , Beshtawi M. , Bader Mohammed , Admour Isra' , Alam S. Mahmood , Zaman Q. , Dham Ruwayda
Published: September 2003

A randomized, two‐way, crossover, bioequivalence study was conducted in 24 fasting, healthy, male volunteers to compare two brands of furosemide 40 mg tablets, Salurin (Julphar, UAE) as test and Lasix (Hoechst AG, Germany) as reference product. The study was performed at the International Pharmaceutical Research Centre (IPRC), in a joint venture with Al‐Mowasah Hospital, Amman, Jordan. One tablet of either formulation was administered with 240 ml of water after a 10 h overnight fast. After dosing, serial blood samples were collected for a period of 12 h. Plasma harvested from blood was analysed for furosemide by a validated HPLC method. Various pharmacokinetic parameters including AUC0–t, AUC0–∝, Cmax, Tmax, T1/2, and elimination rate constant were determined from plasma concentrations of both formulations. Statistical modules (ANOVA and 90% confidence intervals) were applied to AUC0–t, AUC0−∝, and Cmax to assess the bioequivalence of the two brands which revealed no significant difference between them, and 90% CI fell within the US FDA accepted bioequivalence range of 80%–125%. Based on these statistical inferences, Salurin was found to be bioequivalent to Lasix. Copyright © 2003 John Wiley & Sons, Ltd.
Three vehicle formulations for melagatran, a direct thrombin inhibitor, evaluated in a vena cava thrombosis model in the rat
Authors: Elg Margareta , Börjesson Inger , Carlsson Stefan
Published: September 2003

Background—The objective of this study was to investigate whether the use of a depot formulation would enhance the antithrombotic effect of the direct thrombin inhibitor melagatran.

Methods and Results—In a rat venous thrombosis model, animals were openly randomized to receive subcutaneously (s.c.) either vehicle (saline, cyclodextrin or poloxamer) or melagatran (0.5 µ;mol/kg) dissolved in vehicle. An additional injection of cyclodextrin or poloxamer was given at another site to investigate whether the vehicle itself had any additional effect. All injections were given 30 min before induction of thrombus formation. Thrombus formation was induced by ferric chloride, together with stenosis of the caval vein, during a short period of inhalation anaesthesia. Five hours later the thrombi were harvested and their wet weight determined. Thrombus size was comparable across the vehicle‐only groups. The antithrombotic effects of melagatran in saline or poloxamer were comparable while melagatran in cyclodextrin was less effective. The effects of melagatran in saline, cyclodextrin or poloxamer were not enhanced by additional cyclodextrin or poloxamer. Thrombin time (TT) and activated partial thromboplastin time (aPTT) at the end of the experiment were prolonged to a greater extent in the groups receiving melagatran in cyclodextrin or poloxamer compared with those receiving melagatran in saline.

Conclusion—In this vena cava thrombosis model, no enhanced antithrombotic effect was observed with melagatran given as a s.c. depot formulation in cyclodextrin or poloxamer compared with that in saline. Copyright © 2003 John Wiley & Sons, Ltd.
Determination of 3‐n‐butylphthalide in rabbit plasma by HPLC with ﬂuorescence detection and its application in pharmacokinetic study
Authors: Zhao Chunshun , He Zhonggui , Cui Shengmiao , Zhang Ruhua
Published: September 2003

A rapid, sensitive and speciﬁc reversed‐phase high‐performance liquid chromatographic method was developed for the determination of 3‐n‐butylphthalide, a drug currently being developed for treatment of stroke, in rabbit plasma. Fluorescence detection at an excitation wavelength of 280 nm and an emission wavelength of 304 nm was used for quantiﬁcation of 3‐n‐butylphthalide. Ibuprofen was used as internal standard. Plasma samples were extracted with diethyl ether under acidic conditions. After evaporation of the organic phase, the extract was dissolved in mobile phase and injected into the chromatograph with C18 column and a mobile phase of 0.05 mol/L sodium acetate buffer (pH 4.5)–acetonitrile (400:600). The peak area ratio vs concentration in plasma was linear over the range of 0.0212–4.24 µg/mL (correlation coefﬁcient r = 0.9984) and the limit of quantiﬁcation was 0.0212 µg/mL. Mean recovery was determined as 101.0% by analysis of plasma standard samples containing 0.0424, 0.424, 2.12 and 4.24 µg/mL of 3‐n‐butylphthalide. The intra‐day relative standard deviations (RSDs) ranged from 3.6 to 8.9% and inter‐day RSDs were within 8.0%. Pharmacokinetics of a single intravenous dose of 3‐n‐butylphthalide to the rabbits was presented to illustrate the applicability of this method. 3‐n‐Butylphthalide exhibited linear pharmacokinetics after intravenous administration to rabbits over the dose range 1–10 mg/kg. Copyright © 2003 John Wiley & Sons, Ltd.
Experimentelle Untersuchung der Fluiddynamik eines Strahlschichtapparates mit zwei Gaseintritten
Authors: Piskova E. , Mörl L. , Mitev D. , Krüger G.
Published: September 2003

No abstracts.
Reaktionstechnische Untersuchungen und kinetische Modellierung monolithischer Mikroreaktoren mit neuartigen Polymer/Träger‐Festphasenreaktanden
Authors: Schönfeld H. , Cecilia R. , Kunz U.
Published: September 2003

No abstracts.
Aufbau‐ bzw. Abbaupfade von gebildeten Zwischenprodukten bei der Hydropyrolyse von Glucose als Modellsubstanz für nasse Biomasse im Rohrreaktor
Authors: Sinağ A. , Kruse A. , Schwarzkopf V.
Published: September 2003

No abstracts.
Messung und Simulation von Konzentrationsprofilen bei der Trocknung binärer Polymerlösungen
Authors: Schabel W. , Scharfer P. , Müller M. , Ludwig I. , Kind M.
Published: September 2003

No abstracts.
Bestimmung von Faserstruktur und Packungsdichteverteilung in Tiefenfiltermedien mittels MRI
Authors: Lehmann M.J. , Hardy E.H. , Meyer J. , Kasper G.
Published: September 2003

No abstracts.
Einsatz der NIR‐Spektroskopie zur Detektion von Betain in der Zuckerindustrie
Authors: Harbeck C. , Faurie R. , Scheper T.
Published: September 2003

No abstracts.
Volumenanteils‐ und Partikelgrößenbestimmung mittels dielektrischer Spektroskopie
Authors: Regier M. , Schubert H. , Schuchmann H.P.
Published: September 2003

No abstracts.
Numerische Simulation der Partikelhaftung an der Rohrwand bei Gas/Feststoffströmungen
Authors: Heinl E. , Bohnet M.
Published: September 2003

No abstracts.
Membraneinlass‐Massenspektrometrie zur prozessnahen metabolischen Flussanalyse am Beispiel der Lysin‐Produktion von Corynebacterium glutamicum
Authors: Yang T.H. , Wittmann C. , Heinzle E.
Published: September 2003

No abstracts.
Untersuchungen zur Abreinigungsleistung verschiedener Rückpulssysteme für Oberflächenfilter aus starren Filtermedien
Authors: Heidenreich S. , Haag W. , Mai R. , Leibold H. , Seifert H.
Published: September 2003

No abstracts.
Einfluss des Partikelkollektives auf die Filterkuchenbildung und ‐entfeuchtung
Authors: Anlauf H. , Sorrentino J.A.
Published: September 2003

No abstracts.
Vergleich von Sedimentations‐ und Strukturanalyse im Hinblick auf Entstabilisierungsvorgänge in Suspensionen
Authors: Beiser M. , Bickert G. , Scharfer P.
Published: September 2003

No abstracts.
Modellierung der Entfeuchtung körniger Materialien im Dekanter
Authors: Stiborsky M. , Herlawanto R. , Rabold F.
Published: September 2003

No abstracts.
Beeinflussung der Schlammkompression in Vollmantelzentrifugen
Authors: Erk A. , Luda B.
Published: September 2003

No abstracts.
Untersuchungen zur Produktqualität kristalliner Stoffe bei der Fest/Flüssig‐Trennung in Produktionsprozessen
Authors: Bentz M.
Published: September 2003

No abstracts.
Zusammenhang zwischen rheologischen Eigenschaften konzentrierter kolloidaler Suspensionen und der Struktur tauchgezogener Schichten
Authors: Günther L. , Peukert W.
Published: September 2003

No abstracts.