bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preparation of composites of polymer liquid crystal/cholesteric liquid crystal and their photochemical switching and memory properties by photoisomerization of a chiral azobenzene molecule
Authors: Kurihara Seiji , Yoshioka Teppei , Zahangir Alam Md , Ogata Tomonari , Nonaka Takamasa 
Published: April 2004

AbstractA chiral azobenzene compound was synthesized, and mixing the chiral azobenzene compound in a host nematic liquid crystal (LC) induced a cholesteric phase. The twisting power of the trans‐form of the chiral azobenzene compound was larger than that of its cis‐form produced by ultraviolet irradiation. A low molecular weight compensated nematic LC was then prepared by mixing of the chiral azobenzene and a nonphotochromic chiral compound, thus giving mutual opposite helical sense in the host LC. Reversible optical switching between transparent and opaque was achieved by ultraviolet and visible light irradiation. However, the photochemically switched opaque state was not stable even in the dark. Stability of the opaque state was found to be improved by adding polymer LC to the low molecular weight compensated nematic LC. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2577–2580, 2004
Flame retardancy of poly(butylene terephthalate) blended with phosphorous compounds
Authors: Ishikawa Tomoyuki , Maki Ikuhiro , Takeda Kunihiko 
Published: April 2004

AbstractThe thermal degradation and flame retardancy of poly(butylene terephthalate) (PBT) were studied with a focus on the effect of phosphorous compounds. Thermogravimetric analysis, pyrolysis/gas chromatography/mass spectrometry (Py/GC/MS), and elemental analysis were used to analyze the flame retardancy, which were observed by an Underwriters Laboratory UL‐94 test and a cone calorimeter. The 50% degradation temperatures of PBT blends with phosphorous compounds were the same as that of neat PBT. Six scission products were assigned by Py/GC/MS. The burning times of the UL test of several PBT blends were much shorter than that of neat PBT. The relation between flame retardancy and thermal degradation was analyzed with respect to the results of the scission products and the char in burned polymers. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2326–2333, 2004
Enhancement of corrosion protection effect of poly(styrene‐co‐acrylonitrile) by the incorporation of nanolayers of montmorillonite clay into copolymer matrix
Authors: Yeh Jui‐Ming , Liou Shir‐Joe , Lu Hsin‐Jung , Huang Hsi‐Ya 
Published: April 2004

AbstractA series of polymer–clay nanocomposite (PCN) materials that consisted of poly(styrene‐co‐acrylonitrile) (PSAN) and layered montmorillonite (MMT) clay were successfully prepared by effectively dispersing the inorganic nanolayers of MMT clay into the organic PSAN matrix by a conventional in situ thermal polymerization. First of all, organic styrene and AN monomers at a specific feeding ratio were simultaneously intercalated into the interlayer regions of organophilic clay hosts and followed by a typical free‐radical polymerization with benzyl peroxide as initiator. The as‐synthesized PCN materials were subsequently characterized by FTIR spectroscopy, wide‐angle powder X‐ray diffraction, and transmission electron microscopy. The as‐prepared PCN materials, in the form of coatings, incorporated with low clay loading (e.g., 1 wt %) on cold‐rolled steel, were found to be much superior in corrosion protection over those of bulk PSAN based on a series of standard electrochemical measurements of corrosion potential, polarization resistance, and corrosion current in 5 wt % aqueous NaCl electrolyte. Molecular weights of PSAN extracted from PCN materials and bulk PSAN were determined by gel permeation chromatography with THF as eluant. Effects of the material composition on the molecular barrier and thermal stability of PSAN along with PCN materials, in the form of both membrane and fine powder, were also studied by molecular permeability analysis, differential scanning calorimetry, and thermogravimetric analysis, respectively. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2269–2277, 2004
Relation between strain hardening and wear resistance of polymers
Authors: Mergler Y. J. , Schaake R. P. 
Published: April 2004

AbstractThe friction and abrasive wear of blends of polystyrene (PS) and poly(2,6‐dimethyl‐1,4‐phenylene oxide) (PPO) were measured. The coefficient of friction decreases only slightly with an increasing PPO fraction, while the abrasive wear decreases largely upon the introduction of increasing amounts of PPO. It is clearly shown that the abrasive wear resistance of the PS/PPO blends increases with an increasing strain hardening modulus of the blend. The wear rate change between 20 and 40 wt % PPO is ascribed to a transition in the failure mechanism from predominantly brittle to predominantly tough. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2689–2692, 2004
Synthesis and lyotropic behavior of mesogen‐linked cellulose acetates
Authors: Wu Changcheng , Gu Qincui , Zhang Rongben , Huang Yong , Chen Shouxi 
Published: April 2004

AbstractThree aromatic (p‐carboxyl phenyl) esters, 4‐(benzoyloxy) benzoic acid, 4‐(4′‐methylbenzoyloxy) benzoic acid, and 4‐(4′‐chlorobenzoyloxy) benzoic acid, were synthesized and they showed nematic monotropic or thermotropic behavior. The mesogen‐linked cellulose acetates were first prepared by the reaction of aromatic (p‐carboxyl phenyl) esters with cellulose acetate through esterification in the presence of N,N‐dicyclohexylcarbodiimide (DCC) and 4‐dimethylaminopyridine (DMAP). Their degrees of mesogenic unit substitution (DS‐meso) were between 0.27 and 0.41. It was found that they can form cholesteric lyotropic phases in dichloroacetic acid and their critical concentration was about 25 wt %. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2693–2697, 2004
Influence of acrylonitrile–butadiene–styrene (ABS) morphology and poly(styrene‐co‐acrylonitrile) (SAN) content on fracture behavior of ABS/SAN blends
Authors: Yamakawa Roberto S. , Correa Carlos A. , Hage Elias 
Published: April 2004

AbstractThis study attempted to correlate morphological changes and physical properties for a high rubber content acrylonitrile–butadiene–styrene (ABS) and its diluted blends with a poly(styrene‐co‐acrylonitrile) (SAN) copolymer. The results showed a close relationship between rubber content and fracture toughness for the blends. The change of morphology in ABS/SAN blends explains in part some deviations in fracture behavior observed in ductile–brittle transition temperature shifts. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2606–2611, 2004
Surface modification of poly(propylene) by photoinitiators: Improvement of adhesion and wettability
Authors: Castell P. , Wouters M. , de With G. , Fischer H. , Huijs F. 
Published: April 2004

AbstractDifferent benzophenone‐type photoinitiators were photografted onto poly(propylene) (PP). The polymer surfaces were analyzed by means of contact angle measurements, UV spectroscopy, and FTIR‐ATR. The modified samples showed a better wettability and higher surface energies, increasing from 26 mN/m for pure PP to 36 mN/m for the modified samples. The UV spectrum of the modified PP films showed two absorption bands that could be related to the grafted initiator. The effect of irradiation time and photoinitiator concentration was investigated. Different acrylates were grafted efficiently onto the modified polymer surfaces. FTIR‐ATR and contact angle measurements confirmed the presence of the grafted chains. The surface energy of the grafted surfaces of samples increased to 70 mN/m, depending on the type of acrylate used. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2341–2350, 2004
Combined experimental and computer simulation study of the kinetics of solute release from a relaxing swellable polymer matrix. I. Characterization of non‐Fickian solvent uptake
Authors: Papadokostaki K. G. , Petrou J. K. 
Published: April 2004

AbstractThis article is concerned with a combined experimental and computer modeling study aimed at the characterization of the non‐Fickian absorption of liquid water by cellulose acetate (CA) matrices (in the form of thin films) on the basis of a strictly limited number of parameters. The observed kinetics exhibited two distinct non‐Fickian features, resulting from short‐term and long‐term viscous structural relaxations of the swelling glassy polymeric matrix. These relaxation processes were modeled by the extension of a previous model of micromolecular diffusion in a polymer subject to a single relaxation process. The successful simulation of the experimental kinetic curves then enabled the determination and cross‐checking of the relevant model parameter values. This work had the dual purpose of providing (1) input related to solvent absorption for the quantitative computer simulation (in part II of this series) of a model monolithic, solvent‐activated, controlled‐release device, consisting of a swellable glassy polymeric matrix (CA) loaded with an osmotically active solute (NaCl), and (2) an example of a general strategy of extracting meaningful values of micromolecular diffusivity in glassy polymers from non‐Fickian absorption kinetic data. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2458–2467, 2004
Effect of chitin addition on injection‐molded thermoplastic corn starch
Authors: Rosa R.C.R. Souza , Andrade C.T. 
Published: April 2004

AbstractA new type of biodegradable starch‐based composites was prepared by injection‐molding using glycerol and water as plasticizers. Chitin flakes, obtained from shells of Penaeusschmitti, were used as reinforcing phase. The effect of chitin content on the structural and tensile properties of the composite samples was examined after conditioning at 28°C and 80% relative humidity for 30 days. In general, chitin incorporation into the starch matrix resulted in materials with higher modulus and decreased elongation at break. Wide‐angle X‐ray diffraction and differential scanning calorimetry evidenced a significant decrease in crystallinity in the composite samples in relation to the unfilled starch material. Contact angle measurements revealed that the addition of chitin contributes to the improvement of water resistance of the composite samples when compared to injection molded starch alone. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2706–2713, 2004
Synthesis and pyrolysis of Ti‐containing precursors for advanced Si/C/N/Ti‐based ceramics
Authors: Zheng Zhimin , Li Yongming , Luo Yongming , Su Shunxing , Zhang Zhijie , Yang Shiyan , Gao Wei , Xie Zemin 
Published: April 2004

AbstractA new kind of polytitanosilazane (PTSZ) precursor for Si/C/N/Ti‐based ceramic was synthesized from the condensation reaction of silazane lithium salts and titanium tetrachloride (TiCl4). Titanium in the precursors was bonded to silazane compounds in the Si—N—Ti bond. The obtained PTSZs were characterized by Fourier transform infrared (FTIR), nuclear magnetic resonance (NMR), and elemental analyses. The PTSZs were pyrolyzed at 900 to 1300°C under nitrogen, argon, and ammonia atmosphere, respectively, to give amorphous inorganic products. The results indicated that ceramic yields of PTSZs were much higher than that of their corresponding silazane oligomers and ceramic yields increased with the increase in Ti content in PTSZs. Precursors containing reactive vinyl groups gave higher pyrolytic yields. The pyrolytic yield under ammonia is lower than that under nitrogen and argon. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2733–2739, 2004
Are the cometary outbursts caused by impacts with interplanetary vagabonds probable?
Authors: Gronkowski P. 
Published: April 2004

AbstractThe possibility of impacts and their results in relation to the cometary outbursts between comets and other small bodies in the solar system has been investigated. Taking into consideration certain physical features of cometary nuclei and impacting bodies, the probability of impacts of small bodies moving in the main asteroid belt with hypothetical comets which represent three types: Jupiter family comets, Halley family comets and long period comets has been computed. The probability of impacts between comets and meteoroids at large heliocentric distances has also been estimated. Potential consequences of these events in relation to outbursts of the cometary brightness have been discussed. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A calibration map for Wide Field Imager photometry
Authors: Koch A. , Odenkirchen M. , Grebel E.K. , Caldwell J.A.R. 
Published: April 2004

AbstractWe present a prescription to correct large‐scale intensity variations affecting imaging data taken with the Wide Field Imager (WFI) at the MPG/ESO 2.2 m telescope at the European Southern Observatory at La Silla in Chile. Such smoothly varying, large‐scale gradients are primarily caused by non‐uniform illumination due to stray light, which cannot be removed using standard flatfield procedures. By comparing our observations to the well‐calibrated, homogeneous multicolour photometry from the Sloan Digital Sky Survey we characterise the intensity gradients across the camera by secondorder polynomials. The application of these polynomials to our data removes the gradients and reduces the overall scatter.We also demonstrate that applying our correction to an independent WFI dataset significantly reduces its large‐scale variations, indicating that our prescription provides a generally valid and simple tool for calibrating WFI photometry. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The science case of the PEPSI high‐resolution echelle spectrograph and polarimeter for the LBT
Authors: Strassmeier K. G. , Pallavicini R. , Rice J. B. , Andersen M. I. , Zerbi F. M. 
Published: April 2004

AbstractWe lay out the scientific rationale for and present the instrumental requirements of a high‐resolution adaptiveoptics Echelle spectrograph with two full‐Stokes polarimeters for the Large Binocular Telescope (LBT) in Arizona. Magnetic processes just like those seen on the Sun and in the space environment of the Earth are now well recognized in many astrophysical areas. The application to other stars opened up a new field of research that became widely known as the solarstellar connection. Late‐type stars with convective envelopes are all affected by magnetic processes which give rise to a rich variety of phenomena on their surface and are largely responsible for the heating of their outer atmospheres. Magnetic fields are likely to play a crucial role in the accretion process of T‐Tauri stars as well as in the acceleration and collimation of jet‐like flows in young stellar objects (YSOs). Another area is the physics of active galactic nucleii (AGNs) , where the magnetic activity of the accreting black hole is now believed to be responsible for most of the behavior of these objects, including their X‐ray spectrum, their notoriously dramatic variability, and the powerful relativistic jets they produce. Another is the physics of the central engines of cosmic gamma‐ray bursts, the most powerful explosions in the universe, for which the extreme apparent energy release are explained through the collimation of the released energy by magnetic fields. Virtually all the physics of magnetic fields exploited in astrophysics is somehow linked to our understanding of the Sun's and the star's magnetic fields. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
New concept for testing General Relativity: the Laser Astrometric Test Of Relativity (LATOR) mission
Authors: Turyshev S.G. , Shao M. , Nordtvedt K. 
Published: April 2004

AbstractThis paper discusses a Fundamental physics experiment that will test relativistic gravity at the accuracy better than the effects of the second order in the gravitational field strength, ∝ G2. The Laser Astrometric Test Of Relativity (LATOR) mission uses laser interferometry between two micro‐spacecraft whose lines of sight pass close by the Sun to accurately measure deflection of light in the solar gravity. The key element of the experimental design is a redundant geometry optical truss provided by a long‐baseline (100 m) multi‐channel stellar optical interferometer placed on the International Space Station (ISS). The spatial interferometer is used for measuring the angles between the two spacecraft and for orbit determination purposes. In Euclidean geometry, determination of a triangle's three sides determines any angle therein; with gravity changing the optical lengths of sides passing close by the Sun and deflecting the light, the Euclidean relationships are overthrown. The geometric redundancy enables LATOR to measure the departure from Euclidean geometry caused by the solar gravity field to a very high accuracy. LATOR will not only improve the value of the parameterized post‐Newtonian (PPN) γ to unprecedented levels of accuracy of 1 part in 108, it will also reach ability to measure effects of the next post‐Newtonian order (c−4) of light deflection resulting from gravity's intrinsic non‐linearity. The solar quadrupole moment parameter, J2, will be measured with high precision, as well as a variety of other relativistic effects including Lense‐Thirring precession. LATOR will lead to very robust advances in the tests of Fundamental physics: this mission could discover a violation or extension of general relativity, or reveal the presence of an additional long range interaction in the physical law. There are no analogs to the LATOR experiment; it is unique and is a natural culmination of solar system gravity experiments. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Topical disposition of two strengths of a 125I‐rhEGF jelly in rat skin wounds
Authors: Duconge J. , Prats P.A. , Valenzuela C. , Aguilera A. , Rojas I. , Becquer M.A. , Alvarez D. , Estrada L. , Alfonso‐Ortíz S. , Hardy‐Rando E. , García‐Pulpeiro O. , Fernández‐Sánchez E. 
Published: April 2004

AbstractGrowth factors have proved to be an effective therapeutic strategy. However, some controversies have arisen concerning their efficacy in topical wound treatments. Stabilization of epidermal growth factors at the wound site and long‐lasting receptor occupancy are important factors for wound repair. This study evaluated the cumulative profiles of two jellies containing 10 or 20 μg of 125I‐rhEGF per gram of jelly, in a rat full‐thickness skin lesion model. The prolonged time‐courses at the wound sites for both strengths compared with saline solutions previously evaluated using a similar skin lesion model are reported. It seems that these two topical formulations that provide more sustained amounts of 125I‐rhEGF over the period of sampling, would probably achieve the required wound healing response in terms of cell proliferation, collagen deposition and protein synthesis. Further studies need to be developed in order to elucidate whether such an in vivo disposition pattern is consistent with an earlier and stronger promotion of wound healing events. Copyright © 2004 John Wiley & Sons, Ltd.
Effect of intravenous infusion time on the pharmacokinetics and pharmacodynamics of the same total dose of torasemide in rabbits
Authors: Kim Yu C. , Lee Myung G. , Ko Seong‐Hee , Kim So H. 
Published: April 2004

AbstractThe pharmacokinetics and pharmacodynamics of torasemide were evaluated after intravenous administration of the same total dose of torasemide at a dose of 1mg/kg to rabbits with different infusion times, 1 min (treatment I), 30 min (treatment II) and 2 h (treatment III). The loss of water and electrolytes in urine induced by torasemide was immediately replaced with infusion of an equal volume of lactated Ringer's solution. All the pharmacokinetic parameters of torasemide, such as total area under the plasma concentration–time curve from time zero to time infinity (AUC), total body clearance (CL), apparent volume of distribution at steady state (Vss), terminal half‐life and mean residence time (MRT), were independent of infusion times. However, the 8h urine output (235, 534 and 808 ml) and 8h urinary excretion of sodium (24.2, 80.1 and 89.2 mmol) and chloride (27.1, 89.2 and 94.0 mmol) were significantly greater in treatments II and III than those in treatment I, although the total 8 h urinary excretion of unchanged torasemide (1210, 1210 and 1310 µg) were not significantly different among the three treatments. This could be due to the higher diuretic efficiencies in treatments II and III. Copyright © 2004 John Wiley & Sons, Ltd.
Pharmacodynamics of controlled release verapamil in patients with hypertension: an analysis using spline functions
Authors: Aarons Leon , Baxter Claire , Gupta Suneel 
Published: April 2004

AbstractAims—To use a nonparametric approach involving longitudinal splines to model the baseline blood pressure profile and investigate the impact of this modelling on the pharmacodynamic analysis for verapamil in patients with angina or hypertension.Methods—Dose ranging studies were conducted in patients with hypertension and with angina. Subjects received doses of 120, 180, 360 or 540mg racemic verapamil. Pharmacodynamic data were created by subtracting the (systolic) blood pressure following active drug from the placebo response, either by direct subtraction or after modelling the baseline with a longitudinal spline model fitted to the placebo data by nonlinear mixed effects modelling. An Emax model was then used to describe the relationship between change in blood pressure and (R‐)verapamil plasma concentration.Results—The maximum decrease in systolic blood pressure was found to be 57.6 (±26.1) mm and the C50 was 420 (±349) µg/l for the data obtained by direct subtraction of the placebo data. Similar results were obtained when a cubic spline model was used to describe each individual's placebo response. However, the use of a population spline model only allowed a linear pharmacodynamic model to be fitted to the resulting data. Sparse data were created by randomly removing 66% of the data from the placebo and active phases. The population spline model gave very similar parameter estimates for the linear model applied to the sparse data to those obtained from the complete data set.Conclusions—The use of a longitudinal spline model together with nonlinear mixed effects modelling to account for baseline blood pressure response can be very powerful in a sparse data environment. Copyright © 2004 John Wiley & Sons, Ltd.
Developmental toxicity of methanol: Pathogenesis in CD‐1 and C57BL/6J mice exposed in whole embryo culture
Authors: Degitz Sigmund J. , Rogers John M. , Zucker Robert M. , Hunter E. Sidney 
Published: April 2004

AbstractBACKGROUNDMethanol causes axial skeleton and craniofacial defects in both CD‐1 and C57BL/6J mice during gastrulation, but C57BL/6J embryos are more severely affected. We evaluated methanol‐induced pathogenesis in CD‐1 and C57BL/6J embryos exposed during gastrulation in whole embryo culture.METHODSConceptuses with five to seven somites were exposed to 0, 1, 2, 3, 4, or 6 mg methanol/ml culture medium for 24 hr and embryonic morphology was assessed. Cell death was evaluated by histology and LysoTracker red staining, and cell‐cycle distribution was evaluated by flow cytometry.RESULTSIn C57BL/6J embryos, craniofacial defects were observed at 3 mg methanol/ml and greater. The response for CD‐1 embryos was different, with increased dysmorphology only at 6 mg/ml. However, protein content in CD‐1 embryos was reduced at 3 mg methanol/ml and above, indicating growth retardation. Yolk sac toxicity occurred only at 6 mg methanol/ml in both strains. Methanol caused only small changes in cell‐cycle distribution, while cell death was induced at 4 and 6 mg methanol/ml in both strains after 8 hr. The extent of cell death after 8 hr was greater in C57BL/6J embryos, and increased over time through 18 hr; in contrast, CD‐1 embryos showed less cell death at 18 than at 8 hr, suggesting recovery.CONCLUSIONSCell death plays a prominent role in methanol‐induced dysmorphogenesis, while cell‐cycle perturbation may not. Differences in the extent of cell death between CD‐1 and C57BL/6J embryos correlated with differences in the severity of dysmorphogenesis. Birth Defects Research (Part A), 2004. Published 2004 Wiley‐Liss, Inc.