bluuebunny/crossref_metadata_2025 huggingface dataset:
Evidence for linkage position determination in known feruloylated mono‐ and disaccharides using electrospray ion trap mass spectrometry
Authors: Quéméner Bernard , Ralet Marie‐Christine
Published: October 2004

Various feruloylated arabinose‐ and galactose‐containing mono‐ and disaccharides with known linkage configurations (2‐O‐(trans‐feruloyl)‐L‐arabinopyranose, 5‐O‐(trans‐feruloyl)‐L‐arabinofuranose, O‐[2‐O‐(trans‐feruloyl)‐α‐L‐arabinofuranosyl]‐(1→5)‐L‐arabinofuranose, and O‐[6‐O‐(trans‐feruloyl)‐β‐D‐galactopyranosyl]‐(1→4)‐D‐galactopyranose) were analyzed by electrospray ionization mass spectrometry using an ion trap or a quadrupole time‐of‐flight (Q‐TOF) mass analyzer. Collision‐induced dissociation (CID) experiments using the two mass analyzers generated similar tandem mass spectrometric (MS/MS) fragmentation patterns. However, the ester‐bond cleavage ions were more abundant using the Q‐TOF mass analyzer. Compared with the positive ion mode, the negative ion mode produces simpler and more useful CID product‐ion patterns. For arabinose‐containing feruloylated compounds, results obtained with both analyzers show that it is possible to assign the location of the feruloyl group to the O‐2 or O‐5 of arabinosyl residues. In the characterization of the 2‐O‐feruloyl and 5‐O‐feruloyl linkages, the relative abundance of the cross‐ring fragment ions at m/z 265 (−60 u or −62 u after 18O‐labelling) and at m/z 217 (−108 u or −110 u after 18O‐labelling) play a relevant role. For galactose‐containing feruloylated compounds, losses of 60, 90 and 120 Da observed in MS3 experiment correspond to the production of 0, 2A1, 0, 3A1 and (0, 2A1 − 60 Da) cross‐ring cleavage ions, respectively, fixing the location of feruloyl group at the O‐6 of the galactose residue. Copyright © 2004 John Wiley & Sons, Ltd.
Preconditioning enhances the expression of mitochondrial antioxidant thioredoxin‐2 in the forebrain of rats exposed to severe hypobaric hypoxia
Authors: Stroev Serguei A. , Gluschenko Tatjana S. , Tjulkova Ekaterina I. , Spyrou Giannis , Rybnikova Elena A. , Samoilov Michail O. , Pelto‐Huikko Markku
Published: October 2004

The impact of severe hypoxia and preconditioning on the expression of the mitochondrial antioxidant thioredoxin‐2 (Trx‐2) in rat hippocampus (CA1, CA2, CA3 fields, and dentate gyrus) and neocortex was studied by immunocytochemistry. The preconditioning consisted of three trials of mild hypobaric hypoxia (360 Torr, 2 hr) spaced at 24 hr. The last trial was followed by severe hypobaric hypoxia (180 Torr, 3 hr) 24 hr later. Both in hippocampus and in neocortex, severe hypobaric hypoxia resulted in enhanced Trx‐2 expression at 3 hr, followed by a slight decline in Trx‐2 levels, which nevertheless remained increased at 24 hr elsewhere except for the CA1 region. The preconditioning considerably augmented severe hypoxia‐induced Trx‐2 immunoreactivity, affecting both the number of immunoreactive cells and the intensity of immunostaining. The findings suggest a role for Trx‐2 in the formation of brain hypoxic/ischemic tolerance accomplished by the preconditioning. © 2004 Wiley‐Liss, Inc.
Regeneration of the inner ear as a model of neural plasticity
Authors: Morest D. Kent , Cotanche Douglas A.
Published: October 2004

The publication of a paper entitled “Direct transdifferentiation gives rise to the earliest new hair cells in regenerating avian auditory epithelium” in the Journal of Neuroscience Research offers the opportunity to call attention to a well‐developed line of research on the auditory receptor of birds, which should be of interest to students of regeneration and plasticity of the mature nervous system in higher vertebrates, including mammals. Although hair cell proliferation normally stops before hatching, destruction of the auditory receptors of the chicken may be followed by complete regeneration of hair cells. Most of the new hair cells arise from a new wave of proliferation, but Roberson et al. show that about one‐third of the new hair cells are formed without undergoing cell division and thus may differentiate from so‐called supporting cells or cells with an “intermediate morphology.” This finding suggests some models for regeneration of this neuroepithelium, including the possibility that mature supporting cells could transform directly into hair cells. The present Mini‐Review discusses some of the models for neural regeneration that future studies might address in the light of our current knowledge and the new report. The possibility is raised that transitional forms of hair cell and supporting cell precursors may reside in the inner ear in a quiescent state until stimulated by damage. © 2004 Wiley‐Liss, Inc.
Astrocyte‐specific overexpression of insulin‐like growth factor‐I promotes brain overgrowth and glial fibrillary acidic protein expression
Authors: Ye Ping , Popken Greg J. , Kemper April , McCarthy Ken , Popko Brian , D'Ercole A. Joseph
Published: October 2004

Insulin‐like growth factor‐I (IGF‐I) is widely expressed in the central nervous system (CNS). Whereas during normal development IGF‐I is expressed predominately by neurons and to a much lesser degree by glial cells, its expression in astrocytes, and often in microglia, is increased during and/or after variety of CNS injuries. Recently we have generated a new line of IGF‐I Tg mice, called IGF‐IAst/Tet‐Off Tg mice, in which IGF‐I transgene is expressed specifically in astrocytes and is tightly controlled by the tetracycline analog doxycycline. In this study we examined whether IGF‐I derived from astrocytes is capable of promoting neural cell growth during development. When the IGF‐I transgene is allowed to be expressed, IGF‐IAst/Tet‐Off Tg mice exhibit markedly increases in 1) brain weight; 2) brain DNA and protein abundance; and 3) number of neurons, oligodendrocytes, and astrocytes, as well as myelination, findings similar to those observed in our other lines of Tg mice that express IGF‐I transgene predominately in neurons. Unlike Tg mice with neuron‐specific IGF‐I expression, which manifest marked increases in the concentrations of oligodendrocyte/myelin‐specific proteins, however, IGF‐IAst/Tet‐Off Tg mice exhibit an increase in the concentration of glial fibrillary acidic protein, an astrocyte‐specific protein. Furthermore, when transgene expression is blunted, brain overgrowth in IGF‐IAst/Tet‐Off Tg mice ceases. Our data indicate that astrocyte‐derived IGF‐I is capable of promoting neural cells growth in vivo. Our data also suggest that IGF‐I's actions in CNS depend in part on the location of its expression and cellular microenvironment and that continuous presence of IGF‐I expression is necessary for brain overgrowth. © 2004 Wiley‐Liss, Inc.
Habituation to a test apparatus during associative learning is sufficient to enhance muscarinic acetylcholine receptor‐immunoreactivity in rat suprachiasmatic nucleus
Authors: Van der Zee Eddy A. , Biemans Barbara A.M. , Gerkema Menno P. , Daan Serge
Published: October 2004

The suprachiasmatic nucleus (SCN) is engaged in modulation of memory retention after (fear) conditioning, but it is unknown which pathways and neurotransmitter system(s) play a role in this action. Here we examine immunocytochemically whether muscarinic acetylcholine receptors (mAChRs), mediating cholinergic signal transduction in the SCN, are involved. For this purpose, mAChR immunoreactivity (mAChR‐ir) was studied in the SCN after various stages of passive shock avoidance (PSA) and active shock avoidance (ASA) training and, for ASA, at various posttraining time points. mAChR‐ir was significantly enhanced in SCN neurons as a result of the training procedure, and the number of mAChR‐positive glial cells in the SCN increased significantly. The increase in mAChR‐ir as a result of PSA and ASA training was not due to fear conditioning or the number of correct avoidances (in case of ASA training) but rather to behavioral arousal as a consequence of (brief) exposure to a novel environment (the test apparatus). This finding was confirmed by a cage‐change experiment in which the rats were allowed to stay in a novel cage for 15 min or 24 hr. Only the brief exposure to the fresh cage triggered alterations for SCN mAChRs 24 hr later. These results shed new light on a possible function of the cholinergic system in the SCN mediated by mAChRs in relation to modulation of memory processes and demonstrate that behavioral arousal during (the habituation stage of) a learning task is sufficient to alter the mAChR system in the SCN. © 2004 Wiley‐Liss, Inc.
Retinal glutamate transporter activity persists under simulated ischemic conditions
Authors: Bull Natalie D. , Barnett Nigel L.
Published: October 2004

Elevated extracellular concentrations of the neurotransmitter glutamate are neurotoxic and directly contribute to CNS damage as a result of ischemic pathologies. However, the main contributors to this uncontrolled rise in glutamate are still unconfirmed. It has been reported that the reversal of high‐affinity glutamate transporters is a significant contributing factor. Conversely, it has also been observed that these transporters continue to take up glutamate, albeit at a reduced saturation concentration, under ischemic conditions. We sought to determine whether glutamate transporters continue to remove glutamate from the extracellular space under ischemic conditions by pharmacologically modulating the activity of high‐affinity retinal glutamate transporters during simulated ischemia in vitro. Retinal glutamate transporter activity was significantly reduced under these ischemic conditions. The suppression of retinal glutamate transporter activity, with the protein kinase C inhibitor chelerythrine, significantly reduced ischemic glutamate uptake and enhanced retinal neurodegeneration. These findings imply a limited but protective role for retinal glutamate transporters under certain ischemic conditions, suggesting that pharmacological enhancement of high‐affinity glutamate transporter activity may reduce tissue damage and loss of function resulting from toxic extracellular glutamate concentrations. © 2004 Wiley‐Liss, Inc.
Hippocampal neurotrophin levels after injury: Relationship to the age of the hippocampus at the time of injury
Authors: Shetty Ashok K. , Rao Muddanna S. , Hattiangady Bharathi , Zaman Vandana , Shetty Geetha A.
Published: October 2004

Aging impairs the competence of the hippocampus for synaptic reorganization after injury. This potentially is due to the inability of the aging hippocampus to up‐regulate the critical neurotrophic factors for prolonged periods after injury to levels at which they can stimulate neurite outgrowth and facilitate synaptic reorganization. We hypothesize that the concentrations of neurotrophins in the hippocampus after injury depend on the age at the time of injury. We quantified the concentrations of brain‐derived neurotrophic factor (BDNF), nerve growth factor (NGF), and neurotrophin‐3 (NT‐3) in the hippocampus of young, middle‐aged, and aged Fischer 344 rats at 4 days after kainic acid (KA)‐induced injury. In comparison with the age‐matched intact hippocampus, the KA‐lesioned hippocampus exhibited increased levels of BDNF and NGF in all three age groups. In contrast, the NT‐3 concentration was unaltered after KA lesion. Notwithstanding similar percentage increases in BDNF after injury, the lesioned middle‐aged and aged hippocampus contained 45–52% less BDNF than the lesioned young hippocampus. NGF and NT‐3 levels after injury were comparable across the three age groups, however. Furthermore, lower BDNF concentration in the injured aging hippocampus was associated with normal astrocytic response but significantly diminished microglial reaction. Thus, in comparison with the injured young hippocampus, the injured aging hippocampus contains considerably less BDNF but similar levels of NGF and NT‐3. Lower BDNF levels in the injured aging hippocampus might underlie the diminished spontaneous healing response observed in the aging hippocampus after injury, particularly in terms of synaptic reorganization and dentate neurogenesis. © 2004 Wiley‐Liss, Inc.
Editorial: Math. Log. Quart. 50, No. 6
Authors: Grossmann Alexander
Published: October 2004

Mathematical logic and foundations of mathematics experienced a large boom in the 1950s and 60s due to their close connections to the theoretical fundamentals of computer science. The theory of algorithms and automata developed in line with computer technology; cybernetics was the buzzword of the times. It was during this exciting period that G�nter Asser founded the Zeitschrift für Mathematische Logik und Grundlagen der Mathematik while doing his doctorate at the Humboldt‐Universität in Berlin, together with his supervisor, Karl Schröter.

The first issue appeared in 1955 and, alongside work by R. Péter and K. Schröter, contained a paper by Günter Asser entitled “Eine semantische Charakterisierung der deduktiv abgeschlossenen Mengen des Prädikatenkalküls der ersten Stufe”. Numerous further works would cement his status as a central figure in logic in East Germany as well as his international reputation.

In 1960 Günter Asser was called to Greifswald University. He gave his students not merely a holistic view of the mathematical disciplines, but also of their history and philosophical background. As time went on, he became Dean of his faculty and Deputy Vice Chancellor (Prorektor) of the University. He went on to become a board member of the GDR Mathematical Society and, in 1977, was elected a member of the Academy of Science.

His companion and mentor of many years, Karl Schröter, died that same year and Günter Asser assumed sole responsibility of the Zeitschrift für Mathematische Logik und Grundlagen der Mathematik. From a scientific viewpoint, the 70s were characterized by a tendency towards complexity theory. Günter Asser's influence was now mainly reflected in many publications from his field as well as in his opening up the journal to contributions on complexity theory.

It is due to Günter Asser that the ZML, which in the meantime is called Mathematical Logic Quarterly, continues to enjoy such an eminent standing among the community, despite scientific and political paradigm shifts. As its editor, he ensured not only the high quality of the papers, but was also actively involved in the technical side of the journal's production.

Günter Asser has accompanied the journal with his untiring, personal commitment for 50 years. We now wish to express our heartfelt thanks to the co‐founder and retiring editor for his efforts on behalf of the journal, and wish him all the best for the future. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Free Radical Polymerization of Acrylonitrile in Green Ionic Liquids
Authors: Cheng Liang , Zhang Yumei , Zhao Tingting , Wang Huaping
Published: October 2004

Free radical polymerization of acrylonitrile (AN) in ionic liquid, 1‐butyl‐3‐methylimidazolium tetrafluoroborate ([bmim][BF4]), 2,2;m1‐azobisisobutyronitrile (AIBN) as initiator was investigated. Early investigations on polymerizations using ionic liquids indicate that they serve as especially good solvents to achieve high molecular weight polymers. Free radical polymerizations result in higher molecular weight polymers, for ionic liquids have low chain transfer constants and act to stabilize the active radical during the process of polymerization. The thermal stability of polymers synthesized in ionic liquids have be improved obviously than that in traditional solvents.
Chitosan‐Pectin Composite Gel Spheres: Effect of Some Formulation Variables on Drug Release
Authors: Sriamornsak Pornsak , Puttipipatkhachorn Satit
Published: October 2004

Chitosan‐pectin composite gel spheres were prepared by ionotropic gelation method. Pectin solution containing indomethacin, a model drug, was extruded into a mixture of chitosan and calcium chloride. The release behavior of indomethacin from composite gel spheres was investigated in‐vitro. The influence of factors affecting release behavior, such as type of pectin, molecular weight of chitosan, cross‐linking time and release medium, were discussed in this study. Adding chitosan into gelation medium could retard the release of indomethacin from gel spheres. The different type of pectin used demonstrated slightly different drug release profiles. The higher molecular weight of chitosan showed less indomethacin release than the lower one. The increased cross‐linking time slowed the drug release from composite gel spheres. The release of indomethacin from composite gel spheres was also dependent on the release medium. The drug release was slower in tris buffer where no phosphate ions which can induce the precipitation of calcium phosphate. The results suggested that the composite gel spheres of pectin and chitosan could be used as a controlled release drug delivery carrier.
Polymer Architectures via Reversible Addition Fragmentation Chain Transfer (RAFT) Polymerization
Authors: Takolpuckdee Pittaya , Westwood James , Lewis David M. , Perrier Sébastien
Published: October 2004

Various versatile chain transfer agents (CTAs) have been synthesized for reversible addition fragmentation chain transfer (RAFT) polymerzation. Such CTAs have been used to modify hydroxyl containing materials and produce well‐controlled molecular architectures such as amphiphilic copolymer from poly (ethylene glycol), AB block copolymer consisting of a biodegradable segment, poly (l‐lactic acid) (PLLA) and grafted copolymers of poly (styrene), poly (methyl methacrylate) and poly (methyl acrylate) from cellulose.
Non‐Isocyanate‐Based Polyurethanes Derived upon the Reaction of Amines with Cyclocarbonate Resins
Authors: Diakoumakos Constantinos D. , Kotzev Dimiter L.
Published: October 2004

Laprolate‐803 (L‐803) was used as the model cyclocarbonate resin for reactivity and kinetic studies of non‐isocyanate‐based solventless polyurethanes derived upon the reaction of amines with the 1,3‐dioxolan‐2‐one (dioxolanone) rings of L‐803. It was shown that the reaction could undergo either acid‐, base‐ or metal‐type catalysis yielding polyurethanes with 100% conversion of the dioxolanone rings at approximately half the time needed for their uncatalyzed counterparts. The activation energy of the reaction of L‐803 with diethylene triamine in the presence or absence of a catalyst was determined via Arhenious studies. The reactivity of amines towards the aforementioned model resin was correlated to their chemical structure. A model non‐isocyanate‐based polyurethane displayed Tg of −1°C (DMA), fast gel time (390 min) at room temperature and good elongation (∼70%).
Styrene/(Styrene Derivative) and Styrene/(1‐Alkene) Copolymerization using Ph2Zn‐Additive Initiator Systems
Authors: Rabagliati Franco M. , Cancino Rodrigo A. , Pérez Mónica A. , Rodríguez Francisco J.
Published: October 2004

Diphenylzinc‐metallocene‐MAO initiator systems have proven to be effective initiator systems for styrene and for substituted styrenes as well as for their styrene/(styrene‐derivative) copolymerization. Titanocene produced almost pure syndiotactic polymers while zirconocenes gave atactic polystyrene together with a low content, less than 20%, of syndiotactic polystyrene. Systems including a zirconocene, particularly ethenyl(bisindenyl)zirconium dichloride were effective initiators of 1‐alkene polymerization and of styrene/1‐alkene copolymerization. Conversion to polymer increases with the molecular size of 1‐alkene. Styrene derivative and styrene/(styrene derivative) polymerization was greatly influenced by the inductive effect of substituent and by steric hindrance due to the monomer.
Approaches to Conjugated Polymers via New Solid State Polymerizations
Authors: Sandman Daniel J. , Njus Jeffrey M. , Tran Bao
Published: October 2004

Solid state polymerization is the most convenient approach for the synthesis of macroscopic polymer single crystals. Motivations for seeking fully crystalline specimens of conjugated polymers other than polydiacetylenes (PDA) are presented. The thermal reactivity of p‐ethynylbenzoiic acid (EBA) is found to be a topochemically initiated solid state polymerization. The studies of EBA led to a new paradigm for solid state reactivity in such systems. Systems related to the paradigm, namely p‐cyanobenzoic acid (CNBA) and p‐cyanocinnamic acid (CNCA) have been studied. Sublimation competed with thermal processes in CNBA and CNCA, and a detailed product description has proved difficult to date. Thermochromism and charge‐transfer transitions in PDA are discussed.
Surface Modification of Chitosan Films‐Grafting Ethylene Glycol Oligomer and Its Effect on Protein Adsorption
Authors: Amornchai Wimonsiri , Hoven Vipavee P. , Tangpasuthadol Varawut
Published: October 2004

This work is a part of a series on surface modification of materials made of chitosan. This report focused on grafting monomethoxy ethylene glycol oligomers (mPEG) on the surface of chitosan films. The chemical reactions were performed by immersing the films in organic solvent containing aldehyde derivative of mPEG. The presence of ethylene glycol moieties was determined by attenuated total reflectance‐infrared spectroscopy (ATR‐IR) and nuclear magnetic resonance (NMR). The hydrophobicity of the modified surface, determined by air‐water contact angle, decreased when the ethylene glycol derivatives were grafted on the film. The modified films were also subjected to protein adsorption study in order to assess their uses in biomedical applications. It was found that the presence of ethylene glycol units reduced the adsorption of proteins (albumin and lysozyme) on the films. We therefore have shown that manipulation of the interaction between chitosan and bio‐macromolecules is possible by chemically modifying the surface of chitosan.
Synthesis and Characterization of a Novel Poly(aryl ether) Containing 4‐Chloro‐2,5‐diphenyloxazole
Authors: Pimpha Nuttaporn , Tantayanon Supawan , Harris Frank
Published: October 2004

4‐Chloro‐2,5‐bis(4‐fluorophenyl)oxazole monomer has successfully been synthesized using cyclization reaction of 4‐fluorobenzoyl cyanide with 4‐fluorobenzaldehyde. This monomer was converted to poly(aryl ether)s by nucleophilic substitution of the fluorine atoms on the benzene rings of oxazole monomer with bisphenol A. The influence of the reaction time on the molecular weight had been investigated. The polymers were identified by FT‐IR,1H‐NMR and TGA. The products exhibited weight‐average molar masses up to 2.81 x 104g mol−1 in GPC. These poly(aryl ether)s showed very high thermal stability up to 363 °C for 5 % weight loss in TGA under N2.
Enthalpic Partition‐Assisted Size Exclusion Chromatography: 1. Principle of Method
Authors: Berek Dusan
Published: October 2004

A novel high performance liquid chromatographic (HPLC) method viz. “enthalpic partition assisted size exclusion chromatography” deliberately combines entropic and enthalpic partition mechanisms. It enables separation of homopolymers according to their molar mass with increased selectivity, as well as discrimination of polymer species differing in their nature/composition. Enthalpic partition of macromolecules takes place between the mobile phase and the stationary “liquid” of a different chemical nature, which is immobilized within pores of an appropriate carrier (a bonded phase). The extent of enthalpic partition depends on the accessibility of bonded phase for macromolecules and on the difference of polymer solubility in the mobile phase and in the solvated bonded phase. The enthalpic partition in favor of column packing arises from better solubility of polymer solutes in the solvated stationary phase compared to the mobile phase. Macromolecules are “pushed” into the solvated stationary phase and their retention volumes (VR) increase. In the area of high molar masses, the extent of enthalpic partition as rule raises with the increasing size of macromolecules. However, under properly chosen experimental conditions the enthalpic partition may rapidly diminish with the sample molar mass (M), likely due to the solubility changes and/or due to partial exclusion of macromolecules from the pores. As result, the corresponding retention volumes sharply drop within a narrow range of M with the increasing size of macromolecules. This results in the log M vs. VR dependences, which resemble in their form that for size exclusion chromatography but are much more flat indicating highly selective separations of homopolymers according to their molar masses. In this way, enthalpic partition “assists” entropic partition (size exclusion). Polymer species, which do not undergo enthalpic partition, elute from the HPLC column in the conventional size exclusion mode and can be discriminated from the partitioning species. Enthalpic partition assisted size exclusion chromatography can be utilized in separation and characterization of various homopolymers, and polymer blends.
Effect of Ground Rubber Powder on Properties of Natural Rubber
Authors: Li Shuyan , Lamminmäki Johanna , Hanhi Kalle
Published: October 2004

Ground rubber powder (GRP) with three different sizes was incorporated into nature rubber matrix with different loading. Cure characteristics, swelling behaviour, crosslink density, tensile fractured surface, and mechanical properties have been studied. Based on the cure characteristics, it is evident that the processability of the rubber compounds has not changed obviously with the different GRP loading. The introduction of GRP in virgin rubber leads to the increase in swelling degree and the decrease in crosslink density. Tensile strength, hardness and abrasion resistant deteriorate with the increase of GRP loading, but the tear resistance gets better. If the ground rubber particles are smaller, the properties are more similar to the virgin rubber. Because of the phase separation of the GRP and matrix, the properties get worse with the bigger ground rubber powder.
Regulation of Cell Structure in Water Blown Rigid Polyurethane Foam
Authors: Mondal Pravakar , Khakhar D.V.
Published: October 2004

Rigid polyurethane foams are generally “closed celled” with a gas entrapped in each cell. The properties of such foams are significantly affected by the cell size distribution and morphology of the cells. For example, in thermal insulation foams, small cells lead to lower thermal conductivity and in foams for buoyancy applications, stronger cell windows are resistant to ingress of water until higher hydraulic pressures. The effect of formulation parameters on the size and structure of rigid polyurethane foams was investigated. Foams were made with different surfactants, with variation of surfactant concentration at different blowing agent concentration, with variation of nucleating agent concentration and with variation of catalyst concentration. Micron sized silica particles were used as nucleating agent. The densities of the foams were in the range of 140 to 165 kg/m3. The cell window areas of different foams have been measured. The bubble size in the polyol depends on the surface tension lowering ability of a surfactant, and the entrainment of a large number of small bubbles during mixing leads to a foam with a small cell size and a narrow cell size distribution. Increasing the concentration of the surfactant reduces the cell size and narrows the distribution. Increasing the proportion of organometallic catalyst in the amount of total catalyst used, results in smaller cell sizes, which are narrowly distributed. Hydraulic resistance of the foams was monitored by measuring buoyancy losses at different hydraulic pressures. Hydraulic resistance of the foams can be improved by decreasing the area and increasing the thickness of the cell windows.
Coregulators and chromatin remodeling in transcriptional control
Authors: Kumar Rakesh , Wang Rui‐An , Barnes Christopher J.
Published: October 2004

Despite many years of investigation by numerous investigators, transcriptional regulatory control remains an intensely investigated and continuously evolving field of research. Transcriptional regulation is dependent not only on transcription factor activation and chromatin remodeling, but also on a host of transcription factor coregulators‐coactivators and corepressors. In addition to transcription factor activation and chromatin changes, there is an expanding array of additional modifications that titrate transcriptional regulation for the specific conditions of a particular cell type, organ system, and developmental stage, and such events are likely to be greatly influenced by upstream signaling cascades. Here, we will briefly review the highlights and perspectives of chromatin remodeling and transcription controls as affected by cofactor availability, cellular energy state, relative ratios of reducing equivalents, and upstream signaling. We also present the C‐terminal binding protein (CtBP) as a novel nuclear receptor (NR) coregulator, which exemplifies the integration of a number of transcriptional regulatory controls. © 2004 Wiley‐Liss, Inc.
Diagnosis and therapy of food allergy
Authors: Crespo Jesús F. , James John M. , Rodriguez Julia
Published: October 2004

According to the recently revised nomenclature for allergy [1] the term “Food Hypersensitivity” is proposed to define a reaction on food exposure causing objectively reproducible symptoms or signs at a dose tolerated by normal subjects. Those reactions to food in which immunologic mechanisms are demonstrated comprise the term “Food Allergy”. Immunologic reactions to food in which an immunoglobulin E (IgE)‐mediated mechanism is established are defined as IgE‐mediated food allergy. This review focuses on IgE‐mediated allergic reactions to foods.
Isolation and characterization of natural Ara h 6: Evidence for a further peanut allergen with putative clinical relevance based on resistance to pepsin digestion and heat
Authors: Suhr Martin , Wicklein Daniel , Lepp Ute , Becker Wolf‐Meinhard
Published: October 2004

Peanut allergy is a significant health problem because of its prevalence and the potential severity of the allergic reaction. The characterization of peanut allergens is crucial to the understanding of the mechanism of peanut allergy. Recently, we described cloning of the peanut allergen Ara h 6. The aim of this study was isolation and further characterization of nAra h 6. We purified nAra h 6 from crude peanut extract using gel filtration and anion exchange chromatography. The preparation was further characterized by two‐dimensional polyacrylamide gel electrophoresis (2‐D PAGE) with subsequent immunoblotting. Stability of nAra h 6 was studied by an in vitro digestibility assay as well as by resistance against thermal processing. Sequencing of nAra h 6 identified the N‐terminal amino acid sequence as MRRERGRQGDSSS. Further results clearly demonstrated stability of nAra h 6 against pepsin digestion and heating. Immunoglobulin G (IgE) binding analysis and its biological activity shown by RBL 25/30‐test of natural Ara h 6 supported the importance of this peanut allergen. Investigation of nAra h 6 revealed evidence for a further peanut allergen with putative clinical relevance based on resistance to pepsin digestion and heat.
Wideband microstrip patch antenna with tilted L‐probe feeding
Authors: Qi Dongsheng , Li Binhong , Liu Haitao
Published: October 2004

A wideband microstrip patch antenna with tilted L‐probe is proposed and studied. Given a tilted L‐shaped probe and substrate height of about 16.8% of the wavelength, a bandwidth of 37.1% is obtained in the design, and the in‐band S11 parameter is improved. The radiation pattern is stable across the band and an average gain of 7.93 dBi is achieved. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 380–382, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20476
Humidity sensing using plastic optical fibers
Authors: Tay C. M. , Tan K. M. , Tjin S. C. , Chan C. C. , Rahardjo H.
Published: October 2004

The use of plastic optical fibers (POFs), curved at the sensing point and coated with cobalt chloride (CoCl2) and gelatin as the overlay material, for relative humidity sensing is demonstrated in this paper. The fiber‐core diameter and bending radius of the sensing point affects the sensitivity of the sensor to a great extent. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 387–390, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20479
40 Gb/s short‐reach transmission in normal dispersion regime using an erbium‐doped waveguide amplifier
Authors: Rocha Mônica L. , Furtado Mario T. , Horiuchi Mariza R. , Oliveira Júlio C. R. F. , Rosolem João B. , Simões Fábio Donati , Barros Miriam R. X. , Rossi Sandro M.
Published: October 2004

We report the short‐reach transmission of a single channel, which is positively prechirped and externally modulated in NRZ format at 40 Gb/s by an electro‐optical Mach–Zehnder modulator. The signal, amplified by a low‐cost waveguide amplifier, propagates in the normal dispersion regime with near error‐free performance. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 419–423, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20488
A new single balanced diode mixer with DGS cell lowpass filter
Authors: Kim Ki‐Byoung , Yun Tae‐Soon , Lee Jong‐Chul
Published: October 2004

In this paper, a single balanced diode mixer using harmonic‐suppressed defected ground structure (DGS) low‐pass filter (LPF) with dumbbell shape is presented. The frequency bandwidth selected is C‐band, with 5.72–5.82 GHz for RF, 5.58–5.68 GHz for LO, and 140 MHz for IF signals. A rat‐race hybrid is designed for the accomplishment of the single balanced type of mixer. A low‐pass filter using DGS is used for good conversion loss and unwanted 2nd and 3rd harmonic suppression. The mixer is compared to a reference mixer with conventional low‐pass filter. When an LO signal with power of 4 dBm at 5.635 GHz is injected, a conversion loss of 6.2 dB is observed for the mixer. Also, LO‐to‐RF and LO‐to‐IF isolations of 30 dB and 40 dB are obtained, respectively. This mixer can be used in the area for wireless LAN application. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 423–425, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20489
A partial H‐plane waveguide as a new type of compact waveguide
Authors: Kim Dong‐Won , Lee Jeong‐Hae
Published: October 2004

A new type of compact waveguide, called a partial H‐plane waveguide, is proposed. Analytic expressions of its proper fields and modes are derived and defined. The cutoff frequencies for each mode are calculated by both analytical and numerical methods. The results show that the dispersion characteristics of the first two dominant modes are the same as those of the conventional rectangular waveguide, while the proposed waveguide's cross section is one‐quarter that of the conventional one. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 426–428, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20490
A microstrip‐to‐slotline transition used to feed a V‐shape dipole
Authors: El Haj Sleimen M. , Himdi M.
Published: October 2004

In this paper, a new feeding network for a V‐shape dipole is presented. It is characterised by its simplicity and robustness. An equivalent circuit of the whole structure operating at 2.5 GHz is proposed and experimentally validated. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 428–430, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20491
Compact dual‐frequency semi‐circular microstrip antenna
Authors: Chen Wenjun , Li Binhong , Tao Xie
Published: October 2004

A single‐layer and single‐probe‐feed dual‐frequency semicircular microstrip antenna with a shorting plane is presented. Compared with a circular microstrip antenna operating at fixed frequencies, a large area reduction can be obtained. By varying the shorting‐plane width, the two resonant frequencies are significantly perturbed. Experimental and simulation impedance behaviors of a typical proposed antenna are given. Good agreement is achieved between them. Their measured radiation patterns are also presented. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 430–432, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20492
Determination of the three‐dimensional, solution‐phase structure of the macrolide antibiotic oxolide in CD2Cl2 and D2O from NMR constraints
Authors: Steinmetz Wayne E. , Sparrow Andrew , Somsouk Ma
Published: October 2004

The three‐dimensional structure of the antibiotic oxolide, (9S,11S)‐11‐amino‐9‐deoxo‐11,12‐deoxy‐9,12‐epoxyerythromycin, was determined in CD2Cl2 through constrained molecular mechanics with constraints derived from proton NMR. The calculations yielded a well‐defined global minimum. Data acquired for oxolide in D2O, although not as complete, indicate that the antibiotic adopts the same conformation in water. Copyright © 2004 John Wiley & Sons, Ltd.
Structured preconditioners for operator equations
Authors: Tyrtyshnikov Eugene
Published: October 2004

We propose and report on the use of block circulant preconditioners for solution of non‐Hermitian linear systems in one important typical application from computational electromagnetics (evaluation of fields from localized sources in a heterogeneous isotropic formation uniform in one particular direction). The essentials of the efficiency and discussion are the fast approximation method (based on Fourier polynomials) and fast algebraic solver (GMRES with block circulant preconditioners). Copyright © 2004 John Wiley & Sons, Ltd.
Deformation mechanisms and mechanical properties of modified polypropylene/wood fiber composites
Authors: Hristov V. N. , Vasileva ST. , Krumova M. , Lach R. , Michler G. H.
Published: October 2004

Mechanical properties and deformation mechanisms of polypropylene (PP)/wood fiber (WFb) composites modified with maleated polypropylene as compatibilizer and styrene‐butadiene rubber (SBR) as impact modifier have been studied. The addition of maleated polypropylene to the unmodified polypropylene/wood fiber composite enhances the tensile modulus and yield stress as well as the Charpy impact strength. SBR does not cause a drop in the tensile modulus and yield strength because of the interplay between decreasing stiffness and strength by rubber modification and increasing stiffness and strength by good interfacial adhesion between the matrix and fibers. The addition of both maleated polypropylene and rubber to the polypropylene/wood fiber composite does not result in an improvement of effects based on maleated polypropylene and rubber, which includes possible synergism. The deformation mechanisms in unmodified polypropylene/wood fiber composite are matrix brittle fracture, fiber debonding and pullout. A polymeric layer around the fibers created from maleated polypropylene may undergo debonding, initiating local plasticity. Rubber particle cavitation, fiber pullout and debonding were the basic failure mechanisms of rubber‐toughened polypropylene/wood fiber composite. When maleated polypropylene was added to this composite, fiber breakage and matrix plastic deformation took place. Polym. Compos. 25:521–526, 2004. © 2004 Society of Plastics Engineers.
The effect of curing additive on the mechanical properties of phthalonitrile‐carbon fiber composites
Authors: Dominguez Dawn D. , Jones Harry N. , Keller Teddy M.
Published: October 2004

Unidirectional carbon fiber‐reinforced phthalonitrile composite panels were fabricated by prepreg consolidation with bis[4‐(4‐aminophenoxy)phenyl]sulfone (p‐BAPS) as the phthalonitrile curing additive. Rheometric measurements and elevated‐temperature, short beam shear tests were used to evaluate the cure of the composite as a function of the cure and postcure conditions. These techniques revealed that a fully cured phthalonitrile composite was obtained when the composite was heated at 375°C for 8 hours. Room‐temperature mechanical properties of the cured composite were then evaluated using short beam shear, tension, and flexural tests. The results are compared with those obtained by curing the phthalonitrile with 1,3‐bis(3‐aminophenoxy)benzene (m‐APB). The data indicate that substitution of p‐BAPS for m‐APB has little effect on the mechanical properties of the cured composite. Elevated‐temperature, short beam shear studies up to 371°C show that the cured phthalonitrile composite retains approximately 70% of its room‐temperature apparent interlaminar shear strength. The composite also retains 70% of its room‐temperature storage modulus up to 450°C. Polym. Compos. 25:554–561, 2004. © 2004 Society of Plastics Engineers.
Antihypertensive treatment is associated with improved left ventricular geometry: the Rotterdam Study
Authors: Bleumink Gysèle S. , Deinum Jaap , Mosterd Arend , Witteman Jaqueline C. M. , Hofman Albert , Stricker Bruno H. Ch.
Published: October 2004

Purpose

Left ventricular hypertrophy (LVH) increases the risk of cardiovascular disease. We evaluated the association between antihypertensive therapy and echocardiographically determined LVH.

Methods and results

The Rotterdam Study is a population‐based prospective cohort study among 7983 participants aged 55 years or over. Echocardiography was performed in 2823 participants. The study population consisted of 740 participants with grade 1 hypertension or antihypertensive monotherapy, without heart failure. Of these, 646 had an adequate echocardiogram for analysis of relative wall thickness (RWT) and 642 for left ventricular mass index. Participants were followed from 1 January 1991 until the date of echocardiography, between September 1992 and June 1993. Outcome measures were defined as being in the highest gender‐specific quintile of left ventricular mass index and as having a RWT higher than 0.43. A Cox regression model with duration of use of antihypertensives defined as time‐dependent covariates was used for data‐analysis. Antihypertensive treatment lowered the risk of increased left ventricular mass index (RR 0.6, 95%CI 0.4–0.9). ACE‐inhibitors, diuretics and β‐blockers all showed a risk reduction. Use of antihypertensives was also associated, although non‐significantly, with a decrease of high RWT (RR 0.8, 95%CI 0.6–1.0). ACE‐inhibitors, β‐blockers and calcium antagonists showed similar risk reductions, while diuretics seemed to increase the risk, possibly by reducing left ventricular end diastolic diameter.

Conclusions

The use of antihypertensive drugs is associated with a decreased risk of echocardiographically determined LVH in a population‐based setting. Copyright Copyright © 2004 John Wiley & Sons, Ltd.
Proteomic approach to identify acute phase response‐related proteins with low molecular weight in loach skin following injury
Authors: Peng Xuanxian , Wu Yajun , Chen Jingan , Wang Sanying
Published: October 2004

Proteome analysis by two‐dimensional gel electrophoresis (2‐DE) together with mass spectrometry was applied to screen acute phase response (APR)‐related proteins with low molecular weight in loach skin following injury. Furthermore, Western blotting and function tests were applied to confirm the results obtained from the proteomic study. Fifteen APR‐related proteins with sixteen spots (PLA with two spots) on a 2‐DE map were identified in this study. Furthermore, six were known acute phase proteins including galactose‐binding lectin (GBL), lysozyme, C3, CD59, double PLA and 50s ribosomal protein; while ATP kinase, zinc finger protein 183, alpha‐neurotoxin homology, angiostatin, serine/threonine kinase, metalloproteinase inhibitor, regulator of G‐protein 4, cryptdin‐9 and disintegrin trigranin were found by our lab to be APR‐related proteins. In addition, our results suggest that proteomes with low molecular weight can be characterized by 2‐DE with a Tris‐tricine system followed by mass spectrometry.
Identification of caspase‐3 degradome by two‐dimensional gel electrophoresis and matrix‐assisted laser desorption/ionization‐time of flight analysis
Authors: Lee Ah Young , Park Byoung Chul , Jang Mi , Cho Sayeon , Lee Do Hee , Lee Sang Chul , Myung Pyung Keun , Park Sung Goo
Published: October 2004

The activation of caspases is a critical event for the execution phase of programmed cell death. Caspases are highly specific in their ability to activate or inhibit many crucial proteins in the cell via site‐specific cleavage. To date, more than 60 proteins have been shown to be substrates of one or more caspases in mammalian cells, and the list is still growing. In this study, to identify human caspase‐3 substrates, we digested lysates obtained from a caspase‐3‐deficient MCF‐7 cell line with purified caspase‐3 and analyzed eliminated or decreased spots by 2‐DE. Proteins degraded by caspase‐3, termed as caspase‐3 degradome, are involved in a variety of cellular functions, such as stress‐responsive proteins, signaling molecules, structural proteins, and unclassified proteins. Interestingly, the cellular level of vinculin, a caspase‐3 substrate, was dramatically reduced during the apoptotic process, where the expression level of caspase‐3 was increased. This degradomic approach could provide a powerful tool in finding physiological substrates of many proteolytic enzymes whose functions remain to be determined.
Towards a proteomic analysis of atopic dermatitis: A two‐dimensional‐polyacrylamide gel electrophoresis/mass spectrometric analysis of cultured patient‐derived fibroblasts
Authors: Park Yong‐Doo , Kim So‐yeon , Jang Hee‐Sun , Seo Eun‐Young , Namkung Jung‐Hyun , Park Hyung‐Seok , Cho Sang Yun , Paik Young‐Ki , Yang Jun‐Mo
Published: October 2004

Atopic dermatitis (AD) is a chronic relapsing inflammatory skin disease typically characterized by a distribution of eczematous skin lesions with lichenification, pruritic excoriations, and dry skin with wide varieties of pathophysiologic aspects. Recently, AD was divided into extrinsic and intrinsic forms according to the presence or absence of an allergy. We investigated alterations in protein expression in primary cultured AD cells from the patient biopsy samples by two‐dimensional gel electrophoresis (2‐DE) and matrix‐assisted laser desorption/ionization‐time of flight. In the primary cultured fibroblasts, we obtained 31 candidate proteins from the two‐dimensional gel image analysis in which 18 proteins were up‐regulated, eight proteins were down‐regulated and five proteins were post‐translationally modified. From these 2‐DE results, we found several candidate genes matched proteomic expression patterns by semiquantitative reverse transcription PCR. Since the exact mechanism of atopic alterations in fibroblasts remains unknown, our results may provide new clues to aid in understanding AD.
Mass spectrometric analysis of tumor necrosis factor receptor‐associated factor 1 ubiquitination mediated by cellular inhibitor of apoptosis 2
Authors: Lee Jong‐Sik , Hong Un‐Sook , Lee Tae H. , Yoon Sungjoo Kim , Yoon Jong‐Bok
Published: October 2004

Signaling complexes formed on tumor necrosis factor receptor 2 (TNF‐R2) contain adaptor proteins TNF‐R‐associated factors (TRAFs) 1 and 2, and cellular inhibitors of apoptosis (cIAPs) 1 and 2 which function as regulators of programmed cell death. TRAF2, cIAP1 and cIAP2 all have RING finger domains known to possess E3 ubiquitin ligase activity, implying that ubiquitination may play an important role in the TNF signaling pathway. In this report, we have shown that cIAP2 specifically mediated ubiquitination and proteasome‐dependent degradation of TRAF1. To identify the sites for cIAP2‐mediated ubiquitination of TRAF1, we used high pressure liquid chromatography coupled with tandem mass spectrometry. Lys185 and Lys193 of TRAF1 were found to be modified with ubiquitin chains. Mutation of Lys185 and Lys193 to Arg almost completely blocked cIAP2‐mediated ubiquitination of TRAF1, indicating that they are the major, if not the only, sites of TRAF1 ubiquitination. Our data suggest that cIAP2 may regulate the turnover of TRAF1 by adding polyubiquitin chains on Lys185 or Lys193 following its recruitment to TNF‐R signaling complexes.