bluuebunny/crossref_metadata_2025_split huggingface dataset:
Adsorption of 3‐ and 4‐benzoylpyridine on colloidal silver particles: a surface‐enhanced Raman scattering study
Authors: Chowdhury Joydeep , Ghosh Manash 
Published: September 2004

AbstractSurface‐enhanced Raman scattering (SERS) spectra of 3‐ and 4‐benzoylpyridine (BP) adsorbed on silver hydrosols were compared with the FTIR and normal Raman spectra in bulk and in solution. With a small fractional change in adsorbate concentration, the SER spectra of isomeric BPs show significant changes in their features, indicating different orientational changes of the different parts of the flexible molecule on the colloidal silver surface with adsorbate concentration. The appearance of a broad, long‐wavelength band in the absorption spectra of the silver sol due to solute‐induced coagulation of colloidal silver particles is found to be red shifted with increase in adsorbate concentration. The SER excitation profiles indicate that the resonance of the Raman excitation radiation with the new aggregation band contributes more to the SERS intensity than that with the original sol band. Copyright © 2004 John Wiley & Sons, Ltd.
Variability in starch physicochemical and functional properties of yam (Dioscorea sp) cultivated in Ivory Coast
Authors: Amani N'Guessan Georges , Buléon Alain , Kamenan Alphonse , Colonna Paul 
Published: September 2004

AbstractAn Erratum has been published for this article in Journal Of the Science of Food and Agriculture 85(5), 889 (2005).Native starches were extracted from 21 cultivars of four yam species representative of the yam population of Ivory Coast. They were first characterized for their proximate composition, starch physico‐chemical properties (amylose content, particle size distribution, crystallinity, thermal properties and intrinsic viscosity). Some functional properties (swelling, solubility and pasting behaviour and paste clarity) were then determined. Analysis of variance and principal component analysis showed that three homogenous groups could be distinguished, mainly based on starch physico‐chemical properties. The first group contained all yam starches of the D alata and the D cayenensis‐rotundata complex species. It was characterized by a large diameter grain (approximately 25 µm), a high amylose content (around 25% db), a high intrinsic viscosity (mean of 190 cm3 g−1), and a high apparent viscosity and clarity of the paste. The second group contained the D esculenta varieties, characterized by a small granule size (diameter 6 µm), a low intrinsic viscosity (121 cm3 g−1), a high gelatinization enthalpy change (19 J g−1) and a low paste viscosity. The D dumetorum sample differed from the D esculenta group by having a pure A‐type crystalline form and an opaque paste. A multiple regression showed that the volume fraction of the dispersed phase and native granule size (or amylose content) could account for close to 80% of the variability of paste apparent viscosity. Gel clarity appeared mainly linked to granule size, small granules from D dumetorum and D esculenta giving the most opaque gels. Copyright © 2004 Society of Chemical Industry
Carrot browning on simulated market shelf and during cold storage
Authors: Zhang Qijing , Tan Soonchye , McKay Allan , Yan Guijun 
Published: September 2004

AbstractBrowning index, degree of browning, total phenolics content and polyphenoloxidase (PPO) activity of three carrot cultivars—Kendo, Ricardo and Stefano—were studied on a simulated market shelf (20 °C) and during cold storage (4 °C). There was a general increase in browning indices and degree of browning during simulated marketing storage for all three cultivars. The three cultivars had similar levels of browning after cold storage but Ricardo reached the highest level after 10 days of simulated shelf life. There appeared to be a rapid increase in total phenolics content during cold storage, which increased further during a simulated marketing trial. The PPO activities of Kendo and Stefano decreased during cold storage whereas that of Ricardo increased, reaching its highest level after 2 months in cold storage. A positive and significant correlation between total phenolics and degree of browning was found for all three cultivars stored for different lengths of time. This research suggests that shorter periods of cold storage reduce the potential for carrot browning and hence prolong the shelf life of carrots. Copyright © 2004 Society of Chemical Industry
Semipreparative isolation of dehydrodiferulic and dehydrotriferulic acids as standard substances from maize bran
Authors: Bunzel Mirko , Funk Carola , Steinhart Hans 
Published: September 2004

AbstractA method for the isolation of diferulic and triferulic acids in quantities and purity that comply with the requirements for their use as standard substances was developed. The procedure includes alkaline hydrolysis of destarched maize bran and ether extraction of liberated phenolic compounds. Following a first purification by liquid‐liquid extraction Sephadex LH‐20 chromatography is performed. This step is the core of the method and allows the separation of monomeric and dimeric/trimeric substances. A good pre‐separation of di‐ and triferulic acids (purity in most cases >75%) is also achieved. Further separation and purification is carried out by semipreparative RP18‐HPLC. Using this rapid, easy to handle, and moderately priced separation procedure it is possible to obtain approx. 41 mg 8‐O‐4´‐diferulic acid, 27 mg 5‐5´‐diferulic acid, 12 mg 8‐5´‐diferulic acid (benzofuran form), 16 mg 8‐5´‐diferulic acid (open form), 11 mg 8‐5´‐diferulic acid (decarboxylated form), 7 mg 8‐8´‐diferulic acid (cyclic form), 5 mg 8‐8´‐diferulic acid (open form), and 10 mg 5‐5´,8´‐O‐4´´‐triferulic acid out of 20 g destarched maize bran. The incorporation of minor modifications allows a further upscaling of this procedure.
Blue‐Green Light Emitting Poly(phenylenevinylene) Derivatives as Candidates for Polymer LEDs: Synthesis and Characterization
Authors: Mahler A. Kai , Schlick Horst , Saf Robert , Stelzer Franz , Meghdadi Farideh , Pogantsch Alexander , Leising Günther , Möller Kai‐Christian , Besenhard Jürgen O. 
Published: September 2004

AbstractSummary: Alkoxy substituted derivatives of poly‐ and oligo[(m‐phenylenevinylene)‐alt‐(p‐phenylenevinylene)] were synthesized via the Wittig (P1, OPV1, OPV2) and the Wittig‐Horner (P2, OPV3, OPV4) condensation routes. The polymers were characterized by 13C NMR, 1H NMR, FT‐IR spectroscopy and GPC. 1H NMR was a convenient tool to distinguish between the cis and trans double bonds in the compounds. Poly[(4‐decyloxy‐1,3‐phenylenevinylene)‐alt‐(1,4‐phenylenevinylene)] (P1) contained cis and trans double bonds in significant amounts, the vinylene configuration of poly[(4‐decyloxy‐1,3‐phenylenevinylene)‐alt‐(2,5‐dipentyloxy‐1,4‐phenylenevinylene)] (P2) was nearly exclusively trans. Model compounds (OPV1–4) were also synthesized to support the structural and optical characterization. UV‐vis absorption, photoluminescence (PL) and cyclic voltammetry measurements have been performed to investigate the influence of the positions and the number of substituents on electronic levels. The polymers exhibited an intensive solid‐state emission in the blue‐green (P1) and the green (P2) region of the spectrum. Light emitting diodes have been fabricated consisting of ITO, PEDOT:PSS, P2 and Ca/Al. They exhibited high luminance of 100 cd · m−2 at 5.9 V and low onset voltages (4.3 V) for the electroluminescence (EL).Schematic representation of a light emitting diode fabricated by use of an alkoxy substituted derivative of poly[(m‐phenylenevinylene)‐alt‐(p‐phenylenevinylene)] (P2).magnified imageSchematic representation of a light emitting diode fabricated by use of an alkoxy substituted derivative of poly[(m‐phenylenevinylene)‐alt‐(p‐phenylenevinylene)] (P2).
Preparation and Characterisation of Hydrophobically Modified Hydroxypropylcellulose: Side‐Chain Crystallisation
Authors: López‐Velázquez Delia , Bello Antonio , Pérez Ernesto 
Published: September 2004

AbstractSummary: Hydroxypropylcellulose has been hydrophobically modified by reaction with different amounts of palmitoyl chloride. When the degree of substitution is sufficiently high, the side chains are able to produce lateral crystallisation, which has been analysed by DSC and diffraction experiments, using both conventional and synchrotron radiation. The melting temperatures and enthalpies depend on the degree of substitution, in such a way that it is relatively easy to get melting temperatures close to that of the human body, although a rather wide melting region is obtained.X‐ray diffractograms of the original HPC sample and of the modified specimens.magnified imageX‐ray diffractograms of the original HPC sample and of the modified specimens.
Soluble Polyimide Containing a Photoreactive 2‐Styrylpyridine Derivative as the Side Group: Synthesis and Characterization
Authors: Kim Woo‐Sik , Ahn Deuk‐Kyoon , Kim Min‐Woo 
Published: September 2004

AbstractSummary: We describe the synthesis and characterization of a soluble photoreactive polyimide. The precursor of the polyimide was prepared from 2,2′‐bis{4‐(3,4‐dicarboxyphenoxy)phenyl}hexafluoropropane dianhydride and 3,3′‐hydroxy‐4,4′‐diaminobiphenyl; the photoreactive polyimide was then prepared by the polymer reaction of the hydroxyl groups in the precursor polymer with 2‐{2‐[4‐(6‐hydroxyhexyloxy)phenyl]ethenyl}pyridine as a photoreactive 2‐styrylpyridine derivative. The photoreactive polymer and its precursor polymer were soluble in various polar organic solvents, and their thin flexible films were easily formed by solution casting. The initial decomposition temperatures of the former and latter polymers were 350 and 470 °C, respectively. The extent of the photochemical reaction of the photoreactive polymer film was measured to be 65.8% at an exposure energy of 1.5 J/cm2. The transmittance of the film was found to be approximately 92% at room temperature and approximately 85% at 200 °C. These results suggest that the polyimide is a photosensitive polymer with good photosensitivity and high optical transparency. The dichroic ratios of the film were between 0.023 and 0.025 when exposed to linearly polarized UV light (LPUVL). The liquid crystal in the film cell was perpendicularly oriented to the electric vector of LPUVL.Polar diagrams of LC cells fabricated from polyimide 6FBPA‐HAB‐SP6 film after irradiation with LPUVL.magnified imagePolar diagrams of LC cells fabricated from polyimide 6FBPA‐HAB‐SP6 film after irradiation with LPUVL.
Cover Picture: Macromol. Mater. Eng. 9/2004
Authors: Pastore Heloise O. , Frache Alberto , Boccaleri Enrico , Marchese Leonardo , Camino Giovanni 
Published: September 2004

Cover: The picture on the cover illustrates heat induced structure modifications in polymer‐layered silicate nanocomposites.Further details can be found in the Full Paper by H. O. Pastore, A. Frache, E. Boccaleri, L. Marchese,* and G. Camino on page 783.
Fourier embeddings and Mihlin‐type multiplier theorems
Authors: Hytönen Tuomas 
Published: September 2004

AbstractRecent theorems on singular convolution operators are combined with new Fourier embedding results to prove strong multiplier theorems on various function spaces (including Besov, Lebesgue–Bôchner, and Hardy). All the results apply to operator‐valued multipliers acting on vector‐valued functions, but some of them are new even in the scalar case. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Some equivalent representations of nonsquare constants of spaces with Orlicz norm
Authors: Yan Ya Qiang 
Published: September 2004

AbstractThe nonsquare constants in sense of James and Schäffer have the interrelation: CJ (X) · CS(X) = 2 for a Banach space X. For Orlicz sequence and function spaces equipped with Luxemburg norm, the representation of CJ and CS were obtained ([6], [7]). In this paper, we show that the nonsquare constants CJ (lΦ), CJ(LΦ(Ω)) in sense of James and CS(lΦ), CS(LΦ(Ω)) in sense of Schäffer satisfy:(i) if ϕ(t) is concave, then

(ii) if ϕ(t) is convex, then

with lΦ and LΦ(Ω) being the Orlicz sequence space and function space generated by the N‐function Φ(u) with Orlicz norm, ϕ(t) being the right derivative of Φ. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Structure‐Property Relationships in Rubber‐Modified Styrenic Polymers
Authors: Heckmann Walter , McKee Graham Edmund , Ramsteiner Falko 
Published: September 2004

AbstractStyrenic polymers and copolymers are often impact modified with rubber particles. The efficiency of rubber toughening depends mainly on the size of the rubber particles and the degree of cross‐linking. The deformation rate, the temperature, the orientation of the polymer molecules and the efficiency of rubber grafting also influence rubber toughening. It is thought that on impact, cavitation inside the rubber particles occurs which reduces the detrimental dilatational stress in the bulk polymer without forming cracks in the brittle matrix or at the rubber‐matrix interface. Crazing and shearing are facilitated if the rubber particles can easily cavitate. This can be achieved by either avoiding too much cross‐linking or by adding oil (silicone oil in the case of ABS) into the rubber particles, which acts as nuclei for void formation. An electron spectroscopic imaging method is described which allows visualizing the location of the oil. Already after cooling silicone oil modified ABS samples down to liquid nitrogen temperature rubber cavitation is observed. This cavitation is caused by the thermal stress developing due to the differences in thermal expansion coefficient between the rubber phase and the SAN‐matrix and is facilitated by silicone oil. Voiding also leads to an increase of light scattering, which can be detected by an optical microscope using dark field illumination.
Structure, Dynamics and Properties of Materials with Polymers Having Complex Architectures
Authors: Pakula Tadeusz 
Published: September 2004

AbstractVarious non‐linear highly branched polymers such as multiarm stars, block copolymer micelles and bottlebrush‐like polymers have been studied in order to analyze their intramolecular structure and effects of spatial ordering resulting from their specific macromolecular architecture. These polymers constitute a class of compact macromolecules which, due to the high intramolecular density, interact strongly, excluding each other in space. Investigations of the structure and dynamics in such systems, using various experimental methods as well as computer simulations, have been performed. Small angle X‐ray scattering is used to characterize the structure and mechanical spectroscopy is used for the detection of the dynamic behavior of the systems. Simulations have been performed using the cooperative motion algorithm with lattice polymers equivalent to the considered macromolecules. Results of both experiments and the simulation seem to support the concept of slow structural cooperative rearrangements controlling the flow in such systems. The effects are analogous to those related to flow in low molecular liquids but take place on another size scale. The new slow relaxation processes creates new super soft‐states which are characterized by shear modulus plateau lower than 104 Pa.
Phase II enzyme inducer, sulforaphane, inhibits UVB‐induced AP‐1 activation in human keratinocytes by a novel mechanism
Authors: Zhu Ming , Zhang Yuesheng , Cooper Simon , Sikorski Ewa , Rohwer John , Bowden G. Timothy 
Published: September 2004

AbstractUltraviolet (UV) light‐induced activation of activator protein‐1 (AP‐1), resulting at least in part from oxidative stress, promotes skin carcinogenesis. It has not yet been determined whether elevating cellular phase II enzymes and glutathione (GSH) levels inhibits the AP‐1 activation. We have, therefore, examined the effects of two well‐known inducers of phase II enzymes, sulforaphane (SF) and tert‐butylhydroquinone (tBHQ), on UVB‐induced AP‐1 activation, with an AP‐1‐luciferase reporter plasmid that was stably transfected into human HaCaT keratinocytes (HCL14 cells). Exposure of HCL14 cells to SF or tBHQ led to the induction of quinone reductase‐1 (QR‐1), a marker of global cellular phase II enzymes, as well as elevation of cellular GSH levels. Incubation of the cells with 1–10 μM SF or 11–45 μM tBHQ for 24 h resulted in up to 1.4‐fold and 1.7‐fold increase of QR‐1 activity, respectively, and up to 1.5‐fold and 1.6‐fold increases in cellular GSH levels, respectively. AP‐1 activation was dramatically enhanced by irradiating HCL14 cells with 250 J/m2 of UVB. While the above SF treatment dose‐dependently reduced the UVB‐induced AP‐1 activation in HCL14 cells, the tBHQ treatment did not, suggesting that elevating cellular phase II enzymes and GSH levels may not lead to inhibition of UVB‐induced AP‐1 activation. Indeed, depleting cellular GSH by 80% did not affect UVB‐induced AP‐1 activation either. Subsequent electrophoretic mobility shift assays (EMSA) showed that SF added directly to the EMSAs inhibited AP‐1 DNA binding activity, whereas tBHQ was ineffective. Taken together, our results indicated that elevating phase II enzymes and GSH levels in human keratinocytes does not lead to significant inhibition of UVB‐induced AP‐1 activation. The inhibitory effect of SF on UVB‐induced AP‐1 activation appears to be at least partly due to the direct inhibition of AP‐1 DNA binding activity. This direct effect of SF on AP‐1 DNA binding is a novel mechanism for the action of a drug inhibitor of AP‐1 activation. © 2004 Wiley‐Liss, Inc.
The one‐dimensional chemotaxis model: global existence and asymptotic profile
Authors: Hillen Thomas , Potapov Alex 
Published: September 2004

AbstractOsaki and Yagi (2001) give a proof of global existence for the classical chemotaxis model in one space dimension with use of energy estimates. Here we present an alternative proof which uses the regularity properties of the heat‐equation semigroup. With this method we can identify a large selection of admissible spaces, such that the chemotaxis model defines a global semigroup on these spaces.We use scaling arguments to derive the asymptotic profile of the solutions and we show numerical simulations. Copyright © 2004 John Wiley & Sons, Ltd.
An air‐substrate narrow‐patch microstrip antenna with high radiation performance for 2.4 GHz WLAN access point
Authors: Liu Yung‐Tao , Su Che‐Wei , Wong Kin‐Lu , Chen Hong‐Twu 
Published: September 2004

AbstractA new narrow‐patch microstrip antenna with high radiation performance is presented. By using a feeding structure composed of a step‐shaped feeding strip in the air substrate and a coplanar strip in the narrow radiating patch, the proposed antenna shows high gain (about 8.3–9.2 dBi), wide azimuthal radiation pattern (3‐dB beamwidth close to 90°), and reduced cross‐polarization radiation (less than −20 dB) for frequencies across the 2.4‐GHz (2400–2484 MHz) WLAN band. Experimental results of a constructed prototype suitable for application in the 2.4‐GHz WLAN access point are presented and discussed. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 189–192, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20416
On the general energy‐absorption mechanism in the human tissue
Authors: Kivekäs Outi , Lehtiniemi Tuukka , Vainikainen Pertti 
Published: September 2004

AbstractIn this paper, the general energy‐absorption mechanism in human tissue is investigated. The purpose is to increase the understanding of this process, which is important, for example, when designing mobile handset antennas with minimized user interaction. The behavior of the electric fields of small antennas located near a lossy dielectric half‐space, which consists of several material layers, is studied by numerical simulations. Two different RF sources operating at 900 MHz are used: a half‐wave dipole and a patch antenna on a mobile handset chassis. The results show that the peak specific absorption rate (SAR) is not actually related to the antenna current, as has been commonly believed. Instead, the location of the SAR maximums can be explained by inspecting the boundary conditions of the quasi‐static electric near‐fields of the antenna at the air‐tissue interface. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 195–201, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20418
Optical carrier‐suppression of microwave signals with stimulated Brillouin scattering in long fiber ring
Authors: Shen Yichun , Zhang Xianmin , Chen Kangsheng 
Published: September 2004

AbstractA novel and simple system based on stimulated Brillouin scattering in long fiber ring for optical‐carrier suppression is presented. In this system, a large optical carrier reduction can be attained easily at relative low input power. The anti‐Stokes wave is inhibited by adjusting the Stokes wave feedback. Experiments are implemented to suppress the optical carrier of a microwave photonics signal. About 35‐dB optical carrier reduction and a modulation‐gain factor of 27 are achieved. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 258–260, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20436
Structural characterization and quantitation of compound loading of disubstituted benzoates bound to Wang resin through high‐resolution magic angle spinning NMR spectroscopy
Authors: Blas Jesús , Rivera‐Sagredo Alfonso , Ferritto Rafael , Espinosa Juan Felix 
Published: September 2004

AbstractThe combination of 1D and 2D high‐resolution magic angle spinning NMR experiments led to the assignment of the proton and carbon resonances for several disubstituted benzoates bound to a polystyrene resin through a Wang linker. It is shown that the signal corresponding to the methylene protons of the linker can be utilized to monitor the solid‐phase reactions and determine the loading of the compounds on the resin. Copyright © 2004 John Wiley & Sons, Ltd.
The effects of seizures on the connectivity and circuitry of the developing brain
Authors: Swann John W. 
Published: September 2004

AbstractRecurring seizures in infants and children are often associated with cognitive deficits, but the reason for the learning difficulties is unclear. Recent studies in several animal models suggest that seizures themselves may contribute in important ways to these deficits. Other studies in animals have shown that recurring seizures result in dendritic spine loss. This change, coupled with a down‐regulation in NMDA receptor subunit expression, suggests that repetitive seizures may interrupt the normal development of glutamatergic synaptic transmission. We hypothesize that homeostatic, neuroprotective processes are induced by recurring early‐life seizures. These processes, by diminishing glutamatergic synaptic transmission, are aimed at preventing the continuation of seizures. However, by preventing the normal development of glutamatergic synapses, and particularly NMDA receptor‐mediated synaptic transmission, such homeostatic processes also reduce synaptic plasticity and diminish the ability of neuronal circuits to learn and store memories. MRDD Research Reviews 2004;10:96–100. © 2004 Wiley‐Liss, Inc.