bluuebunny/crossref_metadata_2025 huggingface dataset:
Phenotypic characterization and genealogical tracing in an Afrikaner schizophrenia database
Authors: Karayiorgou Maria , Torrington Marie , Abecasis Gonçalo R. , Pretorius Herman , Robertson Brian , Kaliski Sean , Lay Stephen , Sobin Christina , Möller Natalie , Lundy S. Laura , Blundell Maude L. , Gogos Joseph A. , Roos J. Louw
Published: December 2003

Founder populations hold tremendous promise for mapping genes for complex traits, as they offer less genetic and environmental heterogeneity and greater potential for genealogical research. Not all founder populations are equally valuable, however. The Afrikaner population meets several criteria that make it an ideal population for mapping complex traits, including founding by a small number of initial founders that likely allowed for a relatively restricted set of mutations and a large current population size that allows identification of a sufficient number of cases. Here, we examine the potential to conduct genealogical research in this population and present initial results indicating that accurate genealogical tracing for up to 17 generations is feasible. We also examine the clinical similarities of schizophrenia cases diagnosed in South Africa and those diagnosed in other, heterogeneous populations, specifically the US. We find that, with regard to basic sample descriptors and cardinal symptoms of disease, the two populations are equivalent. It is, therefore, likely that results from our genetic study of schizophrenia will be applicable to other populations. Based on the results presented here, the history and current size of the population, as well as our previous analysis addressing the extent of background linkage disequilibrium (LD) in the Afrikaners, we conclude that the Afrikaner population is likely an appropriate founder population to map genes for schizophrenia using both linkage and LD approaches. © 2003 Wiley‐Liss, Inc.
No association between allelic variants of HOXA1/HOXB1 and autism
Authors: Gallagher Louise , Hawi Ziarih , Kearney Geraldine , Fitzgerald Michael , Gill Michael
Published: December 2003

Two recent studies have reported conflicting findings of association of a variant in the HOXA1 gene and autism. To try to resolve the conflict in findings, we conducted an association study in 78 Irish families of the reported DNA variants. We did not find statistically significant association between the variants and autism. Similarly there was no evidence of preferential transmission of variants from parent of either sex to affected offspring. We also report negative findings for HOXB1 variants. We conclude that the HOXA1/B1 are unlikely to be the susceptibility genes for autism in our sample. © 2003 Wiley‐Liss, Inc.
Dinucleotide repeat polymorphism in interferon‐γ gene is not associated with sporadic Alzheimer's disease
Authors: Oda Masaya , Maruyama Hirofumi , Izumi Yuishin , Morino Hiroyuki , Torii Tsuyoshi , Nakamura Shigenobu , Kawakami Hideshi
Published: December 2003

Various factors have been suggested to participate in Alzheimer's disease (AD) pathology, and some inflammatory cytokines may play an important role in the development of AD. Interferon‐γ (IFNG), an important pro‐inflammatory cytokine, is encoded by a single gene mapped to chromosome 12, one of the candidate locus of AD. The first intron in the IFNG gene represents a CA repeat polymorphism that is possible to affect the IFNG secretion dose. We speculate that the polymorphism may have some roles on the inflammatory process and the pathologic change in AD, so we analyzed the IFNG gene polymorphism in 199 Japanese AD patients and 225 Japanese controls. There were no significant differences in allele frequency between the AD and control groups. We conclude that IFNG gene polymorphism is not associated with development of AD. © 2004 Wiley‐Liss, Inc.
Eine Strategie für die Diversitäts‐orientierte Synthese
Authors: Burke Martin D. , Schreiber Stuart L.
Published: December 2003

Anders als die Target‐orientierte Synthese (TOS) und die medizinische oder kombinatorische Chemie, die den Zugang zu einem bestimmten, oft engen Bereich des chemischen Raums anstreben, füllt die Diversitäts‐orientierte Synthese (DOS) den chemischen Raum mit kleinen Molekülen unterschiedlichster Strukturen. Hauptziel von DOS ist es, einen effizienten, drei‐ bis fünfstufigen Zugang zu Kollektiven kleiner Moleküle mit hoher stereochemischer Diversität und Molekülgerüst‐Diversität zu schaffen, die definierte Koordinaten im chemischen Raum einnehmen. Idealerweise erhält man dabei Verbindungen, die nach dem Screening regio‐ und stereoselektiv funktionalisiert werden können. Stereochemische Diversität und Molekülgerüst‐Diversität stellen sicher, dass die Bausteine an der Moleküloberfläche in verschiedenen Ausrichtungen gebunden werden können. Die Retrosynthese war ein Fortschritt für TOS, für die medizinische und die kombinatorische Chemie. Obwohl die Ziele von DOS die Anwendung einer Retrosynthese nicht vorsehen, kann man eine komplementäre Vorgehensweise entwickeln: die vorwärtssynthetische Analyse (forward synthetic‐analysis). Dieses Konzept erleichtert die Entwicklung, die Beschreibung und das Unterrichten von DOS.
Solution‐ and Crystal‐Phase Covalent Modification of Lysozyme by a Purpose‐Designed Organoruthenium Complex. A MALDI‐TOF MS Study of its Metal Binding Sites
Authors: Salmain Michèle , Caro Bertrand , Le Guen‐Robin Françoise , Blais Jean‐Claude , Jaouen Gérard
Published: December 2003

Study of the reaction between the transition organometallic complex 4‐ruthenocenyl 2,6‐dimethylpyrylium tetrafluoroborate and the enzyme hen egg white lysozyme (HEWL) in solution and by diffusion in crystals was performed by use of a combination of spectroscopic and chromatographic methods. Conjugation involving the lysine residues of lysozyme appeared to occur readily, yielding very stable ruthenocenyl pyridinium adducts with average degrees of incorporation ranging from 0.2 to 1.8 metal complexes per protein molecule, depending on reaction conditions. Matrix‐assisted laser desorption ionization time‐of‐flight mass spectrometry (MALDI‐TOF MS) revealed that the protein conjugates were in fact mixtures of unmodified, mono‐, di‐ and sometimes tripyridinium adducts. In combination with reversed‐phased HPLC, we were able to show that six different monoruthenocenyl pyridinium adducts were formed in solution. This result was confirmed by trypsin digestion of a ruthenocenyl pyridinium conjugate and MALDI‐TOF MS analysis of the peptide mixture, which showed that lysines 1, 13, 33, 96, 97 and 116 were involved in the reaction with the pyrylium complex, lysines 13, 33 and 116 being the major binding sites. In the tetragonal crystal state, no binding of the ruthenium complex was shown to occur at lysine 116, owing to steric hindrance at this particular position.
Substituent‐Dependent Reactivity in the Photodimerization of N‐Substituted Dibenz[b,f]azepines
Authors: Querner Jens , Wolff Thomas , Görner Helmut
Published: December 2003

The photoprocesses of a series of N‐substituted dibenz[b,f]azepines (iminostilbenes) were studied by absorption and emission spectroscopy, by laser flash photolysis, and by preparative irradiation with NMR analysis. In solutions, 2π+2π photodimers of N‐cyano and N‐acyl dibenzazepines are formed via the triplet state upon acetone‐ or benzophenone‐sensitized energy transfer. T–T absorption spectra were measured and absorption coefficients were determined. The triplet energy transfer is equally efficient for N‐alkyl dibenzazepines, which do not dimerize. Excited states of nπ* character in the latter cases are discussed to rationalize the different reactivities. In spite of negligible intersystem crossing of 21 dibenzazepine derivatives, photodimers of N‐acyl and N‐cyano dibenzazepines are formed upon direct excitation in concentrated solutions (0.01–0.1 mol dm−3) as well as in the solid state. A selective anti‐configuration of the photodimers was found throughout.
Modular Solid‐Phase Synthetic Approach To Optimize Structural and Electronic Properties of Oligoboronic Acid Receptors and Sensors for the Aqueous Recognition of Oligosaccharides
Authors: Stones Duane , Manku Sukhdev , Lu Xiaosong , Hall Dennis G.
Published: December 2003

This article describes the design and optimization of the first entirely modular, parallel solid‐phase synthetic approach for the generation of well‐defined polyamine oligoboronic acid receptors and fluorescence sensors for complex oligosaccharides. The synthetic approach allows an effective building of the receptor polyamine backbone, followed by the controlled diversification of the amine benzylic side chains. This approach enabled the testing, in a modular fashion, of the effect of different arylboronic acid units substituted with unencumbering para electron‐withdrawing or electron‐donating groups. The feasibility of this approach toward automated synthesis was also investigated with the assembly of a sublibrary of receptors by means of the Irori MiniKan technology. Several sublibraries of anthracene‐capped sensors containing two or three arylboronic acids were synthesized, and their binding to a series of model disaccharides was examined in neutral aqueous media. The calculation of association constants by fluorescence titrations confirmed that subtle changes in the structures of the interamine spacers in the polyamine backbone can have a significant effect on the stability of the resulting complexes. Most importantly, this study led to the determination of the preferred electronic characteristics for the arylboronate units, and suggests that a new generation of receptors containing very electron‐poor arylboronic acids could lead to a significant improvement of binding affinities.
Subcellular distribution of spinophilin immunolabeling in primate prefrontal cortex: Localization to and within dendritic spines
Authors: Muly E. Chris , Smith Yoland , Allen Patrick , Greengard Paul
Published: December 2003

Signal transduction in the nervous system depends on kinases and phosphatases, whose localization is regulated by a large group of scaffolding proteins. In particular, protein phosphatase‐1 mediates dopamine's actions on a variety of substrates, including glutamate receptors, and this, in turn, depends on the binding of protein phosphatase‐1 to its binding protein spinophilin. To better understand spinophilin's role in targeting protein phosphatase‐1 within neurons, we used a combination of preembedding immunoperoxidase and postembedding immunogold labeling and electron microscopy to determine the localization of this scaffolding protein in macaque prefrontal cortex. Consistent with previous reports, spinophilin was found predominantly in dendritic spines, but a significant number of labeled dendritic shafts and, less frequently, glia and preterminal axons were also identified. By using the postembedding immunogold method, we further examined the distribution of spinophilin within dendritic spines. Spinophilin immunoreactivity was present throughout the spine, but the density of label was heterogeneous and defined two domains. The highest density of label was associated with the postsynaptic density and the 100 nm immediately subjacent to it. The deeper region of the spine, further than 100 nm from the postsynaptic density, had a lower density of spinophilin label. The distribution of spinophilin reported in this study supports its role in modulating glutamatergic neurotransmission but also suggests the possibility that spinophilin may target protein phosphatase‐1 to other sites within the spine or to other neuronal or glial compartments. J. Comp. Neurol. 469:185–197, 2004. © 2003 Wiley‐Liss, Inc.
Efficacy in evidence‐based practice
Authors: Bower Peter
Published: December 2003

Evidence‐based practice is concerned with ensuring that patients receive treatments of proven ‘efficacy,’ and this article considers the meaning of ‘efficacy’ in relation to psychological therapy. The concept of efficacy is compared with that of ‘effectiveness’ and the relationship between these terms and the study design concepts of internal and external validity is highlighted. The advantages and disadvantages of efficacy research in psychological therapies are considered, alternatives to efficacy research are discussed and the issues are considered using the practical example of the development of the evidence base for counselling services in primary care settings in the United Kingdom. Copyright © 2003 John Wiley & Sons, Ltd.
Compliance in small claims court: Exploring the factors associated with defendants' level of compliance with mediated and adjudicated outcomes
Authors: Long Jennie J.
Published: December 2003

This study explores how defendants in small claims cases, settled in either mediation or adjudication, react to case outcomes that require them to
make some form of payment to the opposing party. Of particular interest was the relationship between dispute resolution forum and the reasons given
for compliant behavior. Data were drawn from thirty‐nine structured interviews in small claims cases filed in a local justice court. In
mediated cases, defendants tended to comply with case outcomes from a sense of personal responsibility and obligation to fulfill a promise made to
complainants, while defendants in adjudicated cases reported that they complied with the judgment in their case because of their duty to obey the
law.
Syntheses, Crystal Structures and Optical Limiting Properties of Three Novel Organometallic Tungsten‐Copper‐Sulfur Clusters: [PPh4][(η5‐C5Me5)WS3(CuCN)2], [(η5‐C5Me5)WS3Cu2(PPh3)(μ‐CN)]2 and [PPh4][{(η5‐C5Me5)WS3Cu2(CN)(Py)}2(μ‐CN)]
Authors: Lang Jian‐Ping , Xu Qing‐Feng , Ji Wei , Elim Hendry Izaac , Tatsumi Kazuyuki
Published: December 2003

Reactions of [PPh4][(η5‐C5Me5)WS3] with two equivalents of CuCN in MeCN produced a novel trinuclear butterfly‐shaped cluster [PPh4][(η5‐C5Me5)WS3(CuCN)2] (1) in a 70% yield. Treatment of 1 with excess PPh3 or Py gave rise to two different hexanuclear clusters [(η5‐C5Me5)WS3Cu2(PPh3)(μ‐CN)]2 (2) and [PPh4][{(η5‐C5Me5)WS3Cu2(CN)(Py)}2(μ‐CN)] (3), respectively. Compounds 1−3 were fully characterized by spectroscopy and X‐ray crystallography. The structure of the cluster anion of 1 contains a butterfly‐like WS3Cu2 fragment in which each Cu atom is coordinated to one μ‐S atom, one μ3‐S atom, and one terminal CN group. The neutral compound 2 has a double butterfly‐shaped structure in which two WS3Cu2 fragments are interconnected by two Cu−μ‐CN−Cu bridges. The anion of 3 adopts another type of double butterfly‐shaped structure in which the two WS3Cu2 fragments are linked by a single Cu−μ‐CN−Cu bridge. Compared with C60 in terms of the optical limiting (OL) properties measured under identical conditions, 1 and 2 exhibit a relatively good OL performance, whereas the OL effect is not observed for 3. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Synthesis, Structure, and Properties of Biimidazole‐Chelated Arylruthenium Complexes
Authors: Panda Bikash Kumar , Sengupta Suman , Chakravorty Animesh
Published: December 2003

By reacting Ru(η2‐RL)(PPh3)2(CO)Cl (1) with excess 4,5‐dimethyl‐2,2′‐biimidazole (dmbi), organometallics of the type [Ru(η1‐RL)(PPh3)2(CO)(dmbi)](PF6) (2) have been isolated in excellent yield (η2‐RL is C6H2O‐2‐CHNHC6H4R(p)‐3‐Me‐5, η1‐RL is C6H2OH‐2‐CHNC6H4R(p)‐3‐Me‐5 and R is Me, OMe and Cl). In this process the dmbi ligand undergoes five‐membered chelation, the iminium‐phenolato function tautomerizes to the imine‐phenol function and the Schiff base performs a large rotation around the Ru−C bond. The crystal and molecular structure of [Ru(η1‐MeL)(PPh3)2(CO)(dmbi)](PF6)·CH2Cl2 is reported. For steric reasons the carbon monoxide ligand is located syn to the phenolic oxygen atom as opposed to anti in the precursor 1. In the hydrogen bonded imine‐phenol function the O−H, H···N, and N···O distances are 0.83(8), 1.77(8), and 2.552(6) Å, respectively, the O−H···N angle being 156(2)°. The Ru(dmbi) chelate along with the metallated carbon atom and the CO ligand define an equatorial plane from which the metallated aldimine fragment is rotated by 34.5° due to interligand repulsion. This results in two unequal [2.348(2) and 2.411(2) Å] Ru−P bonds and an apparent suppression of the trans influence of the metallated carbanionic site. The cation and anion in the complex are engaged in N−H···F and C−H···F hydrogen bonding, generating a centrosymmetric dimer in the lattice. One of the hydrogen bonds, characterized by H···F, 2.03(8) Å and N−H···F, 166(2)°, is particularly strong. Solutions of 2 absorb near 400 nm and emit near 460 nm with quantum yields and lifetimes of ca. 10−3 and ⩽ 20 ns, respectively. The emission, which probably involves the 3MLCT state incorporating a π*(dmbi) contribution, is peculiar to the coligation of η1‐RL and dmbi to bivalent ruthenium. In dichloromethane solution 2 displays a quasireversible 2+/2 couple near 0.70 V vs. SCE [2+ is the ruthenium(III) analogue of 2]. Coulometrically generated solutions of 2+ display a strong absorption near 400 nm and rhombic EPR spectra with g values near 2.55, 2.15, and 1.83. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Lanthanide Homobimetallic Triple‐Stranded Helicates: Insight into the Self‐Assembly Mechanism
Authors: Elhabiri Mourad , Hamacek Josef , Bünzli Jean‐Claude G. , Albrecht‐Gary Anne‐Marie
Published: December 2003

The self‐assembly mechanism leading to the exclusive formation of a triple‐stranded bimetallic helicate upon reaction of EuIII with a ditopic hexadentate ligand L bearing two carboxylate moieties has been fully elucidated in water for a wide range of [Eu]tot/[L]tot ratios. Using a fruitful combination of electrospray mass spectrometry, potentiometry, UV/Vis spectrophotometry, luminescence, and 1H NMR spectroscopy, the final product Eu2L3 and the intermediate species EuL2 and Eu2L2 have been characterised. The presence of terminal carboxylates in L significantly reduces the electrostatic repulsions of the coordination sites in Eu2L2 and Eu2L3 compared with the corresponding complexes formed with analogous neutral ligands and thus increases the stability of the L‐europium(III) complexes. Kinetic investigations carried out with an excess of L and with an excess of EuIII, show that the self‐assembly proceeds through either EuL2 or Eu2L intermediates depending on the experimental conditions and leads to a pre‐organized Eu2L2 complex by either a “braiding” or a “keystone” mechanism. In the last step, a fast and efficient wrapping of the third ligand strand leads to the target Eu2L3 helicate. The overall process is mainly governed by electrostatic interactions and proceeds via a key double stranded intermediate helicate Eu2L2. To the best of our knowledge, as a result of the fine‐tuning of the coordination properties of L, we present one of the most efficient and cooperative metal/ligand systems for the spontaneous organization of a bimetallic triple‐stranded structure. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Hg2+‐Selective Membrane Potentiometric Sensor Based on a Recently Synthesized Mercapto Compound
Authors: Bagheri Marzieh , Mashhadizadeh Mohammad Hossein , Razee Saied , Momeni Ahmad
Published: December 2003

A new PVC membrane electrode for Hg(II) ion based on a recently synthesized mercapto compound of 2‐benzoylamino‐3‐(4‐chloro‐phenyl)‐thioacrylic acid S‐(2‐mercapto‐4‐methyl‐phenyl) ester is reported. The electrode exhibits a Nernstian response for Hg2+ ions over a wide concentration range (2.0×10−7–3.0×10−2 M) with a slope of 29 (±1). The limit of detection is 5.0×10−8 M. The proposed sensor revealed good selectivities over a wide variety of other cations include hard and soft metals. This electrode could be used in a pH range of 1.0–4.0. It was used as an indicator electrode in potentiometric titration of mercury(II) ions and can be used in the direct determination of Hg2+ in aqueous solutions.
Investigations into Heteropolyanions as Electrocatalysts for the Oxidation of Adrenaline
Authors: Dempsey Eithne , Kennedy Alan , Fay Nigel , McCormac Timothy
Published: December 2003

The electrocatalytic behavior of a group of metal substituted heteropolyanions towards the oxidation of adrenaline was investigated in solution studies using both UV/vis and electrochemical techniques. Of the metal (M′) substituted Dawson phosphotungstates ([P2W17O61M′]n−) examined, iron, copper and vanadium substituted compounds accelerated the oxidation of adrenaline to adrenochrome. Both UV and electrochemical data support this conclusion, though further studies are necessary in order to deduce the exact role the metal plays in this process. The results presented here will form the basis for more thorough investigations into heteropolyanions as catalysts for catecholamines in the immobilized phase with the ultimate development of a sensor for adrenaline.
Development of a Dual‐Band Amperometric Detector for Determination of Ascorbic Acid and Glucose
Authors: Paixão Thiago R. L. C. , Matos Renato Camargo , Bertotti Mauro
Published: December 2003

A flow‐through system cell that allows the direct and simultaneous amperometric determination of ascorbic acid and glucose to be performed is described. The electrolytic cell in a thin layer configuration is composed of a gold and a copper‐modified electrode, polarized at −0.10 and 0.50 V, respectively. By using a 1 mol L−1NaOH solution as carrier electrolyte, amperometric data acquisition was performed simultaneously with a bipotentiostat and the results were analyzed by a multivariate calibration method. Measurements for two commercial pharmaceutical products were carried out without any pretreatment and showed a good correlation with data obtained by using recommended methods. The use of the device to the on‐line quantitative removal of interfering species at the copper electrode is also discussed.
Calculation of curved open channel flow using physical curvilinear non‐orthogonal co‐ordinates
Authors: Zhu1 Mu‐Lan , Shimizu Yasuyuki , Nishimoto Naoshi
Published: December 2003

There are two main difficulties in numerical simulation calculations using FD/FV method for the flows in real rivers. Firstly, the boundaries are very complex and secondly, the generated grid is usually very non‐uniform locally. Some numerical models in this field solve the first difficulty by the use of physical curvilinear orthogonal co‐ordinates. However, it is very difficult to generate an orthogonal grid for real rivers and the orthogonal restriction often forces the grid to be over concentrated where high resolution is not required. Recently, more and more models solve the first difficulty by the use of generalized curvilinear co‐ordinates (ξ,η). The governing equations are expressed in a covariant or contra‐variant form in terms of generalized curvilinearco‐ordinates (ξ,η). However, some studies in real rivers indicate that this kind of method has some undesirable mesh sensitivities. Sharp differences in adjacent mesh size may easily lead to a calculation stability problem oreven a false simulation result. Both approaches used presently have their own disadvantages in solving the two difficulties that exist in real rivers. In this paper, the authors present a method for two‐dimensional shallow water flow calculations to solve both of the main difficulties, by formulating the governing equations in a physical form in terms of physical curvilinear non‐orthogonal co‐ordinates (s,n). Derivation of the governing equations is explained, and two numerical examples are employed to demonstrate that the presented method is applicable to non‐orthogonal and significantly non‐uniform grids. Copyright © 2004 John Wiley & Sons, Ltd.
Oscillations of the siliceous imprint in the central Benguela Upwelling System from MIS 3 through to the early Holocene: the influence of the Southern Ocean
Authors: Romero O. , Mollenhauer G. , Schneider R. R. , Wefer G.
Published: December 2003

Based on a high‐resolution analysis of the diatom signal and biogenic bulk components at site GeoB3606‐1 (25°S, off Namibia), we describe rapid palaeoceanographic changes in the Benguela Upwelling System (BUS) from early MIS 3 through to the early Holocene (55 000 to 7 000 14C yr BP). Coastal upwelling strongly varied at 25°S from MIS 3 through to MIS 2. The abrupt decrease in the accumulation rate of biogenic silica and diatoms from MIS 3 into MIS 2 records rapid oceanographic changes in the BUS off Namibia. During MIS 3, leakage of excess H4SiO4 acid from the Southern Ocean into low‐latitude surface waters, as indicated by the occurrence of Antarctic diatoms, enhanced the production of spores of Chaetoceros at the expense of calcareous phytoplankton. Furthermore, shallower Antarctic Intermediate Water (AAIW) would have enriched the thermocline off Namibia with silicate transported from the Southern Ocean. The strong decrease of the siliceous signal throughout MIS 2 represents a decrease in the nutrient input to the BUS, even though the diatom assemblage is still dominated by spores of the upwelling‐associated diatom genus Chaetoceros. Depletion of silicate in the thermocline from the onset of MIS 2 through to the early Holocene reflects the shutdown of AAIW injection from the Southern Ocean into the BUS, causing upwelled waters to become reduced in silicate, hence less favourable for diatom production. The deglaciation and early Holocene are characterised by the replacement of the upwelling‐associated flora by a non‐upwelling‐related diatom community, reflecting weakened upwelling, retraction of the seaward extension of the chlorophyll filament off Lüderitz, and dominance of warmer waters. Copyright © 2003 John Wiley & Sons, Ltd.
Anomalous behavior of the second and third harmonics generated by femtosecond Cr:forsterite laser pulses in SiC–polymer nanocomposite materials as functions of the SiC nanopowder content
Authors: Konorov S. O. , Akimov D. A. , Ivanov A. A. , Alfimov M. V. , Zabotnov S. V. , Sidorov‐Biryukov D. A. , Fedotov A. B. , Podshivalov A. A. , Fornarini L. , Carpanese M. , Avella M. , Errico M. E. , Fantoni R. , Zheltikov A. M.
Published: December 2003

Femtosecond pulses of 1.25 µm Cr:forsterite laser radiation were used to study second‐ and third‐harmonic generation in silicon carbide nanopowders embedded in a poly(methyl methacrylate) (PMMA) film. Harmonic generation processes extend the analytical and sensing abilities of light‐scattering techniques, including Raman spectroscopy, offering a convenient and efficient approach to the analysis of nanocomposite materials where nanoparticles tend to agglomerate, masking informative features in Raman spectra. The second‐ and third‐harmonic yields are shown to display an anomalous, counterintuitive behavior as functions of the SiC nanopowder content in a polymer film. Whereas harmonic generation in polymer films with a high content of SiC nanocrystals is quenched by the absorption of agglomerating nanoparticles, the influence of absorption is less detrimental in nanocomposite films with a lower SiC content, leading to the growth of the second‐ and third‐harmonic yields. Nanocomposite films with a lower SiC content are also characterized by a higher breakdown threshold, allowing pump pulses with higher fluences to be applied for more efficient harmonic generation. Copyright © 2003 John Wiley & Sons, Ltd.
Time domain fingerprints of a ‘perpendicular’ rotational Raman band: formic acid studied by femtosecond degenerate four‐wave mixing
Authors: Riehn Christoph , Matylitsky Victor V. , Gelin Maxim F.
Published: December 2003

Formic acid (HCOOH) vapor was studied by femtosecond degenerate four‐wave mixing (fs DFWM) and rotational recurrences of J‐, C‐ and K‐type were observed with this time‐resolved rotational spectroscopy. The occurrence of ΔK≠0 transitions can be rationalized with the different anisotropy (oblate vs prolate) of the polarizability and moments‐of‐inertia tensor. Based on comprehensive computer simulations with a general non‐rigid asymmetric rotor model, the experimental spectrum was reproduced very well. From the fitting to the data, rotational and centrifugal distortion constants and also information on the anisotropy of the polarizability tensor were obtained in good agreement with reference values. Copyright © 2003 John Wiley & Sons, Ltd.
Extended wavenumber domain collision‐induced Raman scattering by gaseous neon
Authors: Rachet F. , Chrysos M. , Lothon G. , Moszynski R. , Milet A.
Published: December 2003

A joint experimental and theoretical study of depolarized, I∥(ν), binary collision‐induced Raman scattering spectra by gaseous room‐temperature neon was made. An absolute‐unit calibration of the measured scattering cross‐sections permitted a straightforward comparison of the data with cross‐sections obtained with quantum mechanics. A broad detuning domain was explored, reaching the far spectral wing at wavenumber shifts ν almost twice as large as those probed so far. A novel ab initio symmetry adapted perturbation theory pair‐anisotropy model was employed, yielding spectra in agreement with the experiment. Copyright © 2003 John Wiley & Sons, Ltd.
Effects of 1‐methylcyclopropene and gibberellic acid on ripening of Chinese jujube (Zizyphus jujuba M) in relation to quality
Authors: Jiang Weibo , Sheng Qiang , Jiang Yueming , Zhou Xiangjuan
Published: December 2003

Overripening of Chinese jujube (Zizyphus jujuba M) fruit at the postharvest stage usually results in a dramatic decline in quality. The role of 1‐methylcyclopropene (1‐MCP) and gibberellic acid (GA) in fruit ripening of Chinese jujube during storage in relation to quality was investigated. Fruit ripening of jujube was significantly enhanced by ethylene, whereas rates of respiration and ethylene production of the fruit were reduced by 1‐MCP. Treatment with 1‐MCP or GA delayed the decreases in firmness and vitamin C and reduced the level of ethanol. Furthermore, the effectiveness of 1‐MCP was improved by replicate treatments during storage at 20 or 2 °C. In addition, treatment with GA + 1‐MCP resulted in additive beneficial effects on ripening inhibition of the fruit. Copyright © 2003 Society of Chemical Industry
Thermodynamics of Phase Behavior in PEO/P(EO‐b‐DMS) Homopolymer and Block Co‐Oligomer Mixtures under Pressure
Authors: Jiang Shichun , An Lijia , Jiang Bingzheng , Wolf Bernhard A.
Published: December 2003

The cloud‐point temperatures (Tcl's) of poly(ethylene oxide) (PEO) and poly(ethylene oxide)‐block‐polydimethylsiloxane (P(EO‐b‐DMS)) homopolymer and block‐oligomer mixtures were determined by turbidity measurements over a range of temperatures (105 to 130 °C), pressures (1 to 800 bar), and compositions (10–40 wt.‐% PEO). The system phase separates upon cooling and Tcl was found to decrease with an increase in pressure for a constant composition. In the absence of special effects, this finding indicates negative excess volumes. Special attention was paid to the demixing temperatures as a function of the pressure for the different polymer mixtures and the plots in the T‐ϕ plane (where ϕ signifies volume fractions). The cloud‐point curves of the polymer mixture under pressures were observed for different compositions. The Sanchez‐Lacombe (SL) lattice fluid theory was used to calculate the spinodals, the binodals, the Flory‐Huggins (FH) interaction parameter, the enthalpy of mixing, and the volume changes of mixing. The calculated results show that modified P(EO‐b‐DMS) scaling parameters with the new combining rules can describe the thermodynamics of the PEO/P(EO‐b‐DMS) system well with the SL theory.

Cloud point curves for various PEO/P(EO‐b‐DMS) polymer mixtures at various pressures on the T‐ϕPEO plane.

magnified image

Cloud point curves for various PEO/P(EO‐b‐DMS) polymer mixtures at various pressures on the T‐ϕPEO plane.
Interpretation of Colloidal Dyeing of Polyester Fabrics Treated with N‐Cetylpyridinium Chloride in Terms of Zeta Potential and Surface Free Energy Balance
Authors: Espinosa‐Jiménez Manuel , Ontiveros‐Ortega A. , Padilla‐Weigand R. , Ramos‐Tejada M. M. , Perea‐Carpio R.
Published: December 2003

In this work are presented results about the effect on the surface free energy and zeta potential for the adsorption process of the colloidal dye Disperse Blue 3 (DBlue3) onto polyester fabric (dacron 54, stile 777), when the fabric is pretreated with N‐cetylpyridinium chloride (NCPCl). The zeta potential of the fabric as a function of the pH of the liquid phase shows that both H+ and OH− ions are involved in determining the potential. The negative charge of the fiber is caused by the presence of the carboxyl end‐groups of the polyester, which are generated by the acidic and basic hydrolysis of the fabric in these media. The zeta potential of the DBlue3 as a function of the pH of the liquid phase shows that the negative charge of the dye particles are because of the presence of an OH− group, ionized in aqueous media, in the molecular structure of the dye. The zeta potential of the fabric treated with a 10−3 M solution of NCPCl as a function of the pH of the liquid phase is positive over the whole pH range. This behavior can be attributed to the presence of the pyridinium group in the molecular structure of the surfactant, which is positively charged. The adsorption isotherms of the dye DBlue3 onto a polyester pretreated with NCPCl at 293 K, shows that the presence of the surfactant on the surface of the fabric favors the adsorption of the dye onto the fabric. This fact shows that the pretreatment with NCPCl is a very interesting aspect in the textile industry. On the other hand, the isotherms of the adsorption of the above dye onto the polyester pretreated with a 10−4 M solution of NCPCl, at different temperatures, shows that the amount of the dye absorbed onto the pretreated fabric increases with the increase in temperature. These behaviors can be justified by the analysis of the components of the surface free energy and zeta potential.

Electron microscopy photographs of the fabric pretreated with NCPCl before (top) and after (bottom) dyeing with DBlue3.

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Electron microscopy photographs of the fabric pretreated with NCPCl before (top) and after (bottom) dyeing with DBlue3.
New Polylactide/Layered Silicate Nanocomposites, 6
Authors: Sinha Ray Suprakas , Okamoto Masami
Published: December 2003

The measurement of rheological properties of any polymeric material under molten state is crucial to gain fundamental understanding of the processability of that material. In the case of polymer/layered silicate nanocomposites, the measurements of rheological properties are not only important to understand the knowledge of the processability of these materials, but is also helpful to find out the strength of polymer‐layered silicate interactions and the structure‐property relationship in nanocomposites. This is because rheological behaviors are strongly influenced by their nanoscale structure and interfacial characteristics. In order to get this knowledge in the case of polylactide/montmorillonite nanocomposites, we have studied melt rheological properties of these materials in detail. On the basis of rheological data, we have conducted foam processing of pure polylactide and one representative nanocomposite by a newly developed pressure cell technique using carbon dioxide as a physical‐blowing agent.

The time variation of the elongational viscosity of one of the intercalated polylactide/montmorillonite nanocomposites.

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The time variation of the elongational viscosity of one of the intercalated polylactide/montmorillonite nanocomposites.
Design of a Microfluidic System to Investigate the Mechanical Properties of Layer‐by‐Layer Fabricated Capsules
Authors: Prevot Michelle , Cordeiro Ana L. , Sukhorukov Gleb B. , Lvov Yuri , Besser Ronald S. , Möhwald Helmuth
Published: December 2003

A microfluidic system was designed, fabricated and implemented to study the behavior of polyelectrolyte capsules flowing in microscale channels. The device contains microchannels that lead into constrictions intended to capture polyelectrolyte microcapsules which were fabricated with the well‐known layer‐by‐layer (LbL) assembly technique. The behavior of hollow capsules at the constrictions was visualized and the properties of the capsules were investigated before and after introduction into the device.

Time series of video frames showing capsules being compressed into a constriction.

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Time series of video frames showing capsules being compressed into a constriction.
Tailored Besov spaces and h‐sets
Authors: Bricchi Michele
Published: December 2003

In this paper we define Besov‐type spaces with generalised smoothness on a rather vast class of (isotropic) irregular sets of fractal type in the Euclidean space (h‐sets). As a special case we shall obtain the definition of Besov spaces with the usual scalar‐index of regularity. To deal with this problem we rely on the one hand on the measure‐geometric theory we have developed for h‐sets and, on the other, we rely on some known results for Besov spaces with generalised smoothness in ℝn and on some advanced techniques concerning these function spaces (local means and atoms), which have been recently developed in full generality by W. Farkas and H.‐G. Leopold. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Dynamic Temperature Distribution in Photo‐induced Alignment of Azobenzene Liquid Crystalline Polymer
Authors: Zhao Dan , Zhang Qijin , Lu Yong , Li Jian , Liu Jian , Cheng Xiaofang
Published: December 2003

A theoretical model has been established to describe the dynamic temperature distribution during the alignment of an azobenzene liquid crystalline polymer irradiated by a linearly polarized laser beam. The dynamic heat diffusion equations are used, and the relationship between heat source item and time is introduced, based on experimental results. With the model, the contours of the temperature distribution at different time have been worked out. It can be found from the theoretical model that there is a maximum temperature rise during the photo‐induced alignment, which is coincident with the analysis of experimental observations. The existence of a minimum laser power and an offset photo‐alignment temperature Toff required to carry on photo‐induce alignment are explained based on the theoretical model.

Temperature distribution after two minutes.

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Temperature distribution after two minutes.
Structure of Charged Poly(propylene imine) Dendrimers: Theoretical Investigation
Authors: Govorun Elena N. , Zeldovich Konstantin B. , Khokhlov Alexei R.
Published: December 2003

A mean‐field model for charged dendrimers has been elaborated and applied to Astramol dendrimers of 5th generation in salt‐free solution. The free energy of a dendrimer molecule was minimized with respect to the dendrimer size and to the profile of counterion distribution. The model of highly stretched freely jointed chain was used to describe the elasticity of long branches, the dissociated groups were assumed to be localized mostly on the periphery of the molecule, and the electrostatic interactions were described in the Poisson‐Boltzmann approximation. It was found that the osmotic pressure of counterions leads to moderate expansion of dendrimer molecules upon charging, and a significant fraction of counterions is localized within the dendrimer molecule under typical experimental conditions.

The schematic structure of poly(propylene imine) dendrimers for the 4th generation.

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The schematic structure of poly(propylene imine) dendrimers for the 4th generation.
Modeling of Free‐radical Crosslinking Copolymerization of Acrylamide and N,N′‐Methylenebis(acrylamide) for Radiation Dosimetry
Authors: Fuxman Adrian M. , McAuley Kim B. , Schreiner L. John
Published: December 2003

Over the past decade there has been much interest in the development of three‐dimensional gel dosimeters to aid in the determination of the distribution and magnitude of absorbed dose in clinical radiation therapy. A widely used dosimeter for verification of spatial dose distribution is the polyacrylamide system, sometimes termed polyacrylamide gel (PAG). In this paper, we develop a model to describe the kinetic mechanisms in this gel dosimeter, based on the radiation‐induced copolymerization of acrylamide and bisacrylamide monomers in water and gelatin. Using the proposed model, the conversion of both monomers and total vinyl groups, the concentrations of pendant double bonds (PDB), cyclized groups and crosslinks along the polymer chains as well as temperature changes were simulated. The model predictions and experimental findings in PAG dosimeters agree for a variety of recipes and spatially uniform radiation conditions. Further experiments are required to obtain accurate kinetic parameter estimates and to verify model predictions.

Comparison between the temperatures changes predicted by the model (dotted lines) and experimental data (solid lines) for PAGs irradiated to different doses.

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Comparison between the temperatures changes predicted by the model (dotted lines) and experimental data (solid lines) for PAGs irradiated to different doses.
Expression of the p16INK4a gene and methylation pattern of CpG sites in the promoter region in rat tumor cell lines
Authors: Honoki Kanya , Tsujiuchi Toshifumi , Mori Toshio , Yoshitani Kazuhiro , Tsutsumi Masahiro , Takakura Yoshinori , Mii Yoshio
Published: December 2003

Loss of p16INK4a protein expression has frequently been related to DNA methylation in association with gene silencing. Although the methylation status of exon1α for p16INK4a involvement in various cancers has been extensively analyzed, it has been pointed out that some inconsistencies existed in its relationship to gene silencing of p16INK4a. In this study, we focused on the expression and methylation status in the regions of nt −478 to −201, containing a putative TATA box (nt −401 to −396), and nt −233 to 26, both in a recently cloned 5′ upstream region of rat p16INK4a. We showed that rat lung adenocarcinoma RLCNR did not express the p16INK4a gene, whereas rat osteosarcoma COS1NR and malignant fibrous histiocytoma MFH1NR both expressed it at levels similar to normal fibroblasts, even though the region of nt −233 to 26 was hypermethylated in COS1NR rather than RLCNR. In contrast, the CpG islands near the putative TATA box region were consistently methylated in RLCNR, but not in COS1NR and MFH1NR, as well as in normal fibroblasts. Treatment with 5‐aza 2′‐deoxycytidine induced expression of p16INK4a gene in RLCNR after 48 h, but no changes were observed in COS1NR and MFH1NR. The results indicated that methylation of CpG islands near a TATA box region played a critical role for gene silencing of the rat p16INK4a gene, rather than that of other regions. © 2003 Wiley‐Liss, Inc.
Limit behaviour of the solution of an evolution boundary‐value problem involving the p‐Laplacian operator for the case of an equivalued condition on a shrinking surface
Authors: Li Fengquan
Published: December 2003

In this paper, we discuss the limit behaviour of the solution of an evolution boundary‐value problem involving the p‐Laplacian operator for the case of an equivalued condition on a shrinking surface. Copyright © 2004 John Wiley & Sons, Ltd.
Trapped modes for periodic structures in waveguides
Authors: Edward Julian
Published: December 2003

The Laplace operator is considered for waveguides perturbed by a periodic structure consisting of N congruent obstacles spanning the waveguide. Neumann boundary conditions are imposed on the periodic structure, and either Neumann or Dirichlet conditions on the guide walls. It is proven that there are at least N (resp. N‐1) trapped modes in the Neumann case (resp. Dirichlet case) under fairly general hypotheses, including the special case where the obstacles consist of line segments placed parallel to the waveguide walls. Copyright © 2004 John Wiley & Sons, Ltd.
A new symmetry approach to solve space–time‐dependent KdV systems
Authors: Ruan Hang‐yu , Chen Yi‐xin
Published: December 2003

In this paper, a new method to solve space–time‐dependent non‐linear equations is proposed. After considering the variable coefficient of a non‐linear equation as a new dependent variable, some special types of space–time‐dependent equations can be solved from corresponding space–time‐independent equations by using the general classical Lie approach. The rich soliton solutions of space–time‐dependent KdV equation and mKdV equation are given with the help of the approach. Copyright © 2004 John Wiley & Sons, Ltd.
Sexual dimorphism in interferon‐τ production by in vivo‐derived bovine embryos
Authors: Kimura Koji , Spate Lee D. , Green Mark P. , Murphy Clifton N. , Seidel George E. , Michael Roberts R.
Published: December 2003

Interferon‐tau (IFN‐τ) is an anti‐luteolytic factor responsible for preventing regression of the maternal corpus luteum (CL) during early pregnancy of cattle. In vitro‐produced (IVP) bovine embryos first produce IFN‐τ as blastocysts. In the present study, we have examined whether sexually dimorphic production of IFN‐τ, which is observed among IVP blastocysts, also occurs among in vivo‐produced blastocysts, and whether this difference between the sexes persists to day 14 when silencing of one of the X‐chromosomes in the trophectoderm is complete. Embryos were flushed from cattle that had been superovulated and bred by AI. Blastocysts (63 male, 62 female) recovered between days 8.5 and 9.5 of pregnancy, were cultured individually. No differences were observed between males and females in either their developmental stage or quality at the beginning, during, and at the end of culture. Female embryos produced more IFN‐τ than males by 24 hr (mean values, males: 16.6 ± 3.7, females: 49.4 ± 9.0 pg per embryo; P < 0.05) and 48 hr (male: 189.8 ± 37.1, female: 410.9 ± 66.6 pg per embryo; P < 0.05). However, the variability in IFN‐τ production between individual blastocysts was so great that IFN‐τ secretion is unlikely to be of value as a non‐invasive means to predict embryo sex. When conceptuses were recovered at day 14, elongating males (n = 25) and females (n = 24) were similar in dimension and did not differ in their IFN‐τ production after 4.5 hr (male: 2,550 ± 607, female: 2,376 ± 772 ng per conceptus) and 24 hr (male: 12,056 ± 2,438, female: 8,447 ± 1,630 ng per conceptus) of culture. Thus, sexual dimorphism in IFN‐τ production is observed in both IVP and in vivo‐produced expanded blastocysts, but is lost by day 14 of in vivo development. Mol. Reprod. Dev. 67:193–199, 2004. © 2004 Wiley‐Liss, Inc.
Endophyte‐infected tall fescue diet alters gene expression in heifer luteal tissue as revealed by interspecies microarray analysis
Authors: Jones K.L. , King S.S. , Iqbal M.J.
Published: December 2003

Cattle consuming endophyte‐infected tall fescue grass have an associated reduction in circulating progesterone and reduced reproductive rates. In this study, commercially available rat microarrays were used to analyze the gene expression in luteal tissues from heifers fed endophyte‐free fescue, endophyte‐infected fescue, or endophyte‐infected fescue supplemented with the dopamine (DA) antagonist, domperidone. The number of hybridized spots represented approximately 40% of the total 10,000 rat genes/ESTs evaluated. Each luteal sample was analyzed in triplicate, resulting in within treatment correlation coefficients of ≥0.98. Median values of mRNA abundance from luteal tissue taken from the endophyte‐infected fed heifers revealed 598 genes and ESTs that were down regulated and 56 genes and ESTs that were upregulated compared with luteal mRNA values from the endophyte‐free treatment. There were fewer comparative differences between median values from luteal mRNA from the endophyte‐free versus feeding endophyte‐infected plus domperidone treated heifers. Only 19 genes and ESTs were upregulated and two were down‐regulated. Mol. Reprod. Dev. 67:154–161, 2004. © 2004 Wiley‐Liss, Inc.