bluuebunny/crossref_metadata_2025_split huggingface dataset:
Some properties of styrene‐based ionomers. I
Authors: Suchocka‐Gałaś K. 
Published: April 2003

AbstractSome properties of styrene‐based ionomers containing alkali metal salts of acrylic acid or methacrylic acid have been investigated. A study has been conducted to examine the influence of the acidic content and nature (acrylic or methacrylic) and the nature of the alkali metal salt on the glass transition temperature, density, melt index and activation energy of a flow of the styrene‐based ionomers. The present studies have indicated that the temperature of glass transition (Tg) of sodium ionomers increases as the sodium content rises and the region of the glass transition broadens. The Tg's of the styrene‐acrylic acid (S‐AA) ionomers do not depend on the nature of the alkali metal introduced into the copolymer. The density of films rises with the content of acid or salt introduced to the polystyrene chain. The melt index of the investigated ionomers depends on the amount and type of the introduced acid and salt as well as on the molecular weight of the initial copolymer. The energy of activation of the flow is independent of the polymer molecular weight; however, the energy of activation of flow of the ionomers increases with larger ionic radii of the introduced alkali metal. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 55–62, 2003
Direct polycondensation of N‐trimellitylimido‐L‐isoleucine with aromatic diamines
Authors: Mallakpour Shadpour , Hajipour Abdol‐Reza , Hassan Shahmohammadi Mohammad 
Published: April 2003

AbstractN‐Trimellitylimido‐L‐isoleucine (3) was prepared from the reaction of trimellitic anhydride with L‐isoleucine [L‐2‐amino‐3‐methylvalerianic acid or (2S,3S)‐2‐amino‐3‐methyl‐n‐valerinic acid] in an N,N‐dimethylformamide solution at the refluxing temperature. The direct polycondensation reaction of the monomer imide diacid (3) with 1,4‐phenylenediamine, 4,4′‐diaminodiphenylmethane, 4,4′‐diaminodiphenylsulfone, diaminodiphenylether, 1,5‐naphthalendiamine, 2,4‐diaminotoluene, and 1,3‐phenylenediamine was performed in a medium consisting of triphenyl phosphite, N‐methyl‐2‐pyrolidone (NMP), pyridine, and calcium chloride. The polycondensation was performed under two different conditions: in one method, the reaction mixture was heated in an NMP solution at 60, 90, and then 130°C for different periods of time, and in the other method, the reaction mixture was refluxed only for 1 min in the same solvent. The resulting poly(amide imide)s (PAIs), with inherent viscosities of 0.21–0.37 dL/g, were obtained in high yields. All of these compounds were fully characterized by IR spectra, elemental analyses, and specific rotation measurements. Some structural characterizations and physical properties of these new optically active PAIs were examined. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 116–122, 2003
Characterization of polyelectrolyte effect in poly(acrylic acid) solutions
Authors: Fernandes A. L. P. , Martins R. R. , da Trindade Neto C. G. , Pereira M. R. , Fonseca J. L. C. 
Published: April 2003

AbstractThe viscometric behavior of poly(acrylic acid) solutions, as well as their ion transport properties, were monitored as a function of polymer concentration and the addition of KOH in nonisoionic conditions. Polyelectrolyte effect was studied and characterized by conductivimetry as well as viscometric properties at the infinite dilution limit. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 191–196, 2003
Interaction of antitumoral 9‐aminoacridine drug with DNA and dextran sulfate studied by fluorescence and surface‐enhanced Raman spectroscopy
Authors: Murza Adrian , Alvarez‐Méndez Sergio , Sanchez‐Cortes Santiago , Garcia‐Ramos Jose V. 
Published: April 2003

AbstractFluorescence spectroscopy and surface‐enhanced Raman spectroscopy are applied to study the interaction of the drug 9‐aminoacridine (9AA) with DNA and dextran sulfate. The effect of the electrostatic interaction between the positively charged 9AA and negatively charged groups in relation to the excimer or exciplex emission is investigated. The exciplex emission of 9AA is connected to the intercalation of this drug between nucleic base residues. The importance of negative groups in this interaction is evaluated by using dextran and dextran sulfate as model polymers. The existence of negative charges seems to induce an increase of the drug concentration in the vicinity of the polymers. The role of electrostatic attraction in the 9AA dimerization is confirmed by the excimer emission of 9AA in the presence of dextran sulfate. In the case of DNA, the phosphate groups may induce the drug approach to the DNA chain, but the exciplex fluorescence emission could be due to a charge transfer between the drug and adenine‐rich sequences of DNA. © 2003 Wiley Periodicals, Inc. Biopolymers (Biospectroscopy) 72: 174–184, 2003
Hydration of hyaluronan polysaccharide observed by IR spectrometry. II. Definition and quantitative analysis of elementary hydration spectra and water uptake
Authors: Haxaire K. , Maréchal Y. , Milas M. , Rinaudo M. 
Published: April 2003

AbstractWe recorded a series of spectra of sodium hyaluronan (HA) films that were in equilibrium with their surrounding humid atmosphere. The hygrometry of this atmosphere extended from 0 to 0.97% relative humidity. We performed a quantitative analysis of the corresponding series of hydration spectra that are the difference spectra of the film at a defined hygrometry minus the spectrum of the dried film (hygrometry = 0). The principle of this analysis is to use this series of hydration spectra to define a limited number (four) of “elementary hydration spectra” over which we can decompose all hydration spectra with good accuracy. This decomposition, combined with the measurements of the numbers of H2O molecules at the origin in these elementary hydration spectra of the three characteristic vibrational bands of H2O, allowed us to calculate the hydration number under different relative humidity conditions. This number compares well with that determined by thermogravimetry. Furthermore, the decomposition defines for each hygrometry value which chemical mechanisms represented by elementary hydration spectra are active. This analysis is pursued by determining for the elementary hydration spectra the number of hydrogen bonds established by each of the four alcohol groups found in each disaccharide repeat unit before performing the same analysis for amide and carboxylate groups. These results are later utilized to discuss the structure of HA at various stages of hydration. © 2003 Wiley Periodicals, Inc. Biopolymers (Biospectroscopy) 72: 149–161, 2003
FT‐Raman spectroscopy as diagnostic tool of Congo red binding to amyloids
Authors: Iconomidou Vassiliki A. , Chryssikos Georgios D. , Gionis Vassilis , Hoenger Andreas , Hamodrakas Stavros J. 
Published: April 2003

AbstractChorion is the major component of silkmoth eggshell. More than 95% of its dry mass consists of the A and B families of low molecular weight structural proteins, which have remarkable mechanical and chemical properties protecting the oocyte and developing embryo from environmental hazards. We present data from FT‐Raman spectroscopy of silkmoth chorion and amyloid‐like fibrils formed from peptide analogues of chorion proteins, both unstained and stained by Congo red. The results show that FT‐Raman spectroscopy is not a straightforward diagnostic tool for the specific interactions of Congo red with amyloids: a dilute aqueous solution of the Congo red dye at pH 5.5 and a thin solid film of the dye cast from this solution exhibit the same “diagnostic” Raman shifts relative to the neat Congo red dry powder as do amyloid fibrils formed from peptide analogues of chorion proteins stained by Congo red. An important consequence of this finding is that these shifts of the Raman active modes of Congo red are probably due to the formation of supramolecular dye aggregates in the presence of water. Therefore, this is not an appropriate diagnostic test for Congo red binding to amyloids. © 2003 Wiley Periodicals, Inc. Biopolymers (Biospectroscopy) 72: 185–192, 2003
Gene selection in arthritis classification with large‐scale microarray expression profiles
Authors: Sha Naijun , Vannucci Marina , Brown Philip J. , Trower Michael K. , Amphlett Gillian , Falciani Francesco 
Published: April 2003

AbstractThe use of large‐scale microarray expression profiling to identify predictors of disease class has become of major interest. Beyond their impact in the clinical setting (i.e. improving diagnosis and treatment), these markers are also likely to provide clues on the molecular mechanisms underlining the diseases. In this paper we describe a new method for the identification of multiple gene predictors of disease class. The method is applied to the classification of two forms of arthritis that have a similar clinical endpoint but different underlying molecular mechanisms: rheumatoid arthritis (RA) and osteoarthritis (OA). We aim at both the classification of samples and the location of genes characterizing the different classes. We achieve both goals simultaneously by combining a binary probit model for classification with Bayesian variable selection methods to identify important genes. We find very small sets of genes that lead to good classification results. Some of the selected genes are clearly correlated with known aspects of the biology of arthritis and, in some cases, reflect already known differences between RA and OA. Copyright © 2003 John Wiley & Sons, Ltd.
Approximating L2‐invariants and the Atiyah conjecture
Authors: Dodziuk Józef , Linnell Peter , Mathai Varghese , Schick Thomas , Yates Stuart 
Published: April 2003

AbstractLet G be a torsion‐free discrete group, and let ℚ denote the field of algebraic numbers in ℂ. We prove that ℚG fulfills the Atiyah conjecture if G lies in a certain class of groups D, which contains in particular all groups that are residually torsion‐free elementary amenable or are residually free. This result implies that there are no nontrivial zero divisors in ℂG. The statement relies on new approximation results for L2‐Betti numbers over ℚG, which are the core of the work done in this paper. Another set of results in the paper is concerned with certain number‐theoretic properties of eigenvalues for the combinatorial Laplacian on L2‐cochains on any normal covering space of a finite CW complex. We establish the absence of eigenvalues that are transcendental numbers whenever the covering transformation group is either amenable or in the Linnell class 𝒞. We also establish the absence of eigenvalues that are Liouville transcendental numbers whenever the covering transformation group is either residually finite or more generally in a certain large bootstrap class 𝒢. © 2003 Wiley Periodicals, Inc.
A convenient synthetic route to mannose 6‐phosphonate—cholesteryl conjugate
Authors: Vidal Sébastien , Morère Alain , Montero Jean‐Louis 
Published: April 2003

AbstractA multistep synthesis of a mannose 6‐phosphonate‐based glycolipid is described involving (1) a one‐carbon chain elongation at the 6‐position of mannose, followed by (2) phosphonation, using tris(trimethylsilyl)phosphite. This method was shown to e efficient and provides a general route to various mannose 6‐phosphonate‐based compounds for the design of drug delivery systems. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:241–246, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10134
Psychosocial problems in Parkinson's disease: Evaluation of a disease‐specific questionnaire
Authors: Spliethoff‐Kamminga Noëlle G.A. , Zwinderman Aeilko H. , Springer Machiel P. , Roos Raymund A.C. 
Published: April 2003

AbstractOur objective was to evaluate the BELA‐P‐k, a questionnaire for measuring psychosocial problems and need for help in Parkinson's disease (PD) patients. The Belastungsfragebogen Parkinson kurzversion (BELA‐P‐k) was translated from German into Dutch. It consists of 19 items distributed over four subscales: achievement capability/physical symptoms, fear/emotional functioning, social functioning and partner‐bonding/family, with a “Bothered by” (Bb) and a “Need for Help” (NfH) score. The BELA‐P‐k was tested for cultural differences, relevance, and feasibility in a pilot study (n = 10) and compared in a validation study (n = 54) with the Sickness Impact Profile, the COOP/WONCA Functional Health Assessment Charts and the Loneliness Questionnaire. All questionnaires were administered in person at home, in a prescribed order. The BELA‐P‐k was completed by 64 patients with PD. The internal‐consistency reliability coefficients for the total Bb (0.90) and NfH (0.93) scales were excellent. The internal consistency of the subscales exceeded the 0.70 standard except for the “Bothered by partner‐bonding/family scale” (0.61). Almost all BELA‐P‐k subscales correlated highly (P < 0.001) with the corresponding scales of the standard quality‐of‐life indices. There was no significant relationship between disease severity (Hoehn and Yahr) and the BELA‐P‐k. We conclude that the BELA‐P‐k is a relevant, reliable and valid measure for assessing psychosocial problems and need for help of PD patients. © 2003 Movement Disorder Society
Microscopic description of information transfer from a qudit to reservoir
Authors: Štelmachovič P. , Ziman M. , Bužek V. 
Published: April 2003

AbstractRecently Ziman et al. [3] have introduced a concept of a universal quantum homogenizer which is a quantum machine that takes as an input a system qubit initially in an arbitrary state ρ and a set of N reservoir qubits initially prepared in the same state ξ. The homogenizer realizes, in the limit sense, the transformation such that at the output each qubit is in an arbitrarily small neighbourhood of the state ξ irrespective of the initial states of the system and the reservoir qubits. In this paper we generalize the concept of quantum homogenization for qudits, that is, for d‐dimensional quantum systems. We prove that the partial swap operation induces a contractive map with the fixed point which is the original state of the reservoir. Finally we propose an optical realization of the quantum homogenization.
Pauli tomography: complete characterization of a single qubit device
Authors: Mazzei A. , Ricci M. , De Martini F. , D'Ariano G.M. 
Published: April 2003

AbstractWe present the first full experimental characterization of a single‐qubit device. This method uses a Pauli Process Tomography at the output of the device and needs only a single entangled state at the input, which works as all possible input states in quantum parallel. The method can be easily extended to any n‐qubits processing device.
Quantum degenerate potassium‐rubidium mixtures
Authors: Modugno G. , Roati G. , Inguscio M. 
Published: April 2003

AbstractWe report on the production of quantum degenerate mixtures of potassium and rubidium isotopes, by means of evaporative cooling in a magnetic trap. Specifically, we produce a Bose–Bose mixture with 41K and 87Rb and Fermi–Bose mixture with 40K and 87Rb. Application of association schemes in these systems may allow the production of degenerate gases of heteronuclear molecules of both bosonic and fermionic character. Ultracold dipolar molecules have been recognized as a viable candidate for the implementation of quantum computing.
Experimental evidence of multimode non‐classical light emission using OPOs
Authors: Maître A. , Treps N. , Martinelli M. , Ducci S. , Fabre C. 
Published: April 2003

AbstractAny spatial measurement below the quantum standard limit requires multitransverse non‐classical light beams which can be produced by a transverse degenerate OPO. A multimode beam is characterized by a non uniform transverse repartition of noise. Using this criterion, we prove experimentally that a confocal Optical Parametric Oscillator emits a multimode non‐classical field.
Studies of femtosecond time‐bin entangled qubits for quantum communications
Authors: Marcikic I. , de Riedmatten H. , Tittel W. , Scarani V. , Acin A. , Tanzilli S. , Zbinden H. , Gisin N. 
Published: April 2003

AbstractWe create pairs of non‐degenerate time‐bin entangled photons at telecom wavelengths with ultra‐short pump pulses. Entanglement is shown by performing Bell kind tests of the Franson type with visibilities of up to 91 time‐bin entanglement can easily be protected from decoherence as encountered in optical fibers, this experiment opens the road for complex quantum communication protocols over long distances.
Rabi oscillations, Ramsey fringes and spin echoes in an electrical circuit
Authors: Vion D. , Aassime A. , Cottet A. , Joyez P. , Pothier H. , Urbina C. , Esteve D. , Devoret M.H. 
Published: April 2003

AbstractWe present a superconducting tunnel junction circuit which behaves as a controllable atom, and whose ground and first excited state form an effective spin 1/2. By applying microwave pulses, we have performed on this circuit experiments demonstrating the controlled manipulation of the spin : Rabi precession, Ramsey interferences, and spin echoes.
Momentum changes due to quantum localization
Authors: Short A.J. 
Published: April 2003

AbstractThe momentum changes caused by localization are a central feature of wave‐particle duality. Investigating these changes in more detail, we find that single‐slit diffraction relies on a form of `interaction‐free' scattering, and that an ideal which‐way measurement can be made without any back‐reaction on the detector. We also consider Kim and Shih's recent realization of Popper's experiment, involving diffraction of entangled particles, and offer an explanation for the results.
Discrete Bose‐Einstein systems in a box with low adiabatic invariant
Authors: Vlad V.I. , Ionescu‐Pallas N. 
Published: April 2003

AbstractThe Bose‐Einstein energy spectrum of an ideal quantum gas confined in a box is discrete and strongly dependent on the box geometry and temperature, for low product of the atomic mass number, Aat and the adiabatic invariant, TV2/3, i.e. on γ = Aat TV2/3. Even within the approximation of non‐interacting particles in the gas, the calculation of the thermodynamic properties of Bose‐Einstein systems turns out to be a difficult mathematical problem. The present study compares the total number of particles, the total energy and the specific heat obtained by sums over the discrete states to the results of the approximate integrals (for defined values of γ) and shows the noticeable errors of the last ones at low adiabatic invariant (around condensation). Then, more rigorous and precise analytical approximations of sums are found in the case of finite number of atoms (correlated with the existence of a zero energy level) and the finite volume of the gas. The corrected thermodynamic functions depend on γ (for fixed fugacity). The condensation temperature is corrected also in order to describe more accurately the discrete Bose‐Einstein systems. Under these circumstances, the analysis of the specific heat leads to the conclusion that it shows no discontinuity, for the entire range of γ values.
Generation of photon number states on demand
Authors: Walther H. 
Published: April 2003

AbstractThe widely discussed applications in quantum information and quantum cryptography require radiation sources capable of producing a fixed number of photons. This paper reviews the work performed in our laboratory to produce these fields on demand. Two different methods are discussed. The first is based on the one‐atom maser or the micromaser operating under the conditions of the so‐called trapping states. In this situation the micromaser stabilises to a photon number state. The second device uses a single ion in an optical cavity. The latter setup was recently realised in our laboratory.
Anti‐inﬂammatory and smooth muscle relaxant activities of the hydroalcoholic extract and chemical constituents from Amburana cearensis A. C. Smith
Authors: Leal L. K. A. M. , Nechio M. , Silveira E. R. , Canuto K. M. , Fontenele J. B. , Ribeiro R. A. , Viana G. S. B. 
Published: April 2003

AbstractAmburana cearensis A. C. Smith, Fagaceae, is a medicinal plant commonly known as ‘cumaru’ and used in Northeast Brazil for the treatment of respiratory tract diseases. In the present work, we investigated the anti‐inﬂammatory and smooth muscle relaxant activities of the hydroalcoholic extract (HAE), coumarin (Coum) and ﬂavonoid fraction (FF) isolated from the trunk barks of Amburana cearensis A. C. Smith. It was shown that HAE (200 and 400 mg/kg), Coum (20 and 40 mg/kg) and FF (40 mg/kg), administered orally, signiﬁcantly inhibited both leukocyte and neutrophil migrations, in the carrageenan or N‐formyl‐methyl‐leucyl‐phenylalanine (fMLP)‐induced migration in rat peritoneal cavity. The increase in cutaneous vascular permeability induced by serotonin in rats was signiﬁcantly blocked by HAE (150 mg/kg, i.p.), Coum (5 mg/kg, i.p.) and FF (20 mg/kg, i.p.). However, only HAE blocked the histamine effect on Evans blue extravasation. In the guinea‐pig trachea precontracted with carbachol (0.3 µM), histamine (0.1 µM) or KCl (0.1 M), the HAE, Coum and FF evoked a concentration‐dependent relaxation in the presence of the three agonists. HAE (100–800 µg/ml) and Coum (4–32 µg/ml) also caused signiﬁcant relaxation of the rat vas deferens previously contracted with adrenaline, acetylcholine or barium chloride. In addition, HAE, Coum and FF inhibited the histamine and serotonin‐induced increase of cutaneous vascular permeability in rats. Copyright © 2003 John Wiley & Sons, Ltd.
Cytotoxic and multidrug resistance reversal activity of a vegetable, ‘Anastasia Red’, a variety of sweet pepper
Authors: Motohashi Noboru , Wakabayashi Hidetsugu , Kurihara Teruo , Takada Yuko , Maruyama Shichiro , Sakagami Hiroshi , Nakashima Hideki , Tani Satoru , Shirataki Yoshiaki , Kawase Masami , Wolfard Kristina , Molnár Joseph 
Published: April 2003

AbstractThe vegetable, Anastasia Red, Capsicum annuum L. var. angulosum Mill. (Solanaceae) was successively extracted with hexane, acetone, methanol and 70% methanol, and the extracts were further separated into a total of 21 fractions by silica gel or octadecylsilane (ODS) column chromatography. The biological activities of extracts and fractions were determined. These extracts showed relatively higher cytotoxic activity against two human oral tumor cell lines (HSC‐2, HSG) than against normal human gingival ﬁbroblasts (HGF), suggesting a tumor‐speciﬁc cytotoxic activity. The cytotoxic activity of these extracts was enhanced by fractionation on silica gel [H2, A2, M1–M3] or ODS column chromatography [70M]. Several fractions [H2, H4, H5, A1, A2, A3, A5, A6, A7, M2] reversed the multidrug resistance (MDR) phenotype with L5178 mouse lymphoma T cells, more efﬁciently than (±)‐verapamil. The extracts and fractions did not show any detectable anti‐human immunodeﬁciency virus (HIV) or anti‐Helicobacter pylori activity. Thus, this study suggests the effective and selective antitumor potential of ‘Anastasia Red’ of sweet pepper for further phytochemical and biological investigation. Copyright © 2003 John Wiley & Sons, Ltd.
In vitro antimicrobial efﬁcacy of leaf essential oils of Chukrasia tabularis Adr. Juss. and Melia dubia Cav. (Meliaceae)
Authors: Nagalakshmi M. A. H. , Thangadurai D. , Pullaiah T. 
Published: April 2003

AbstractThe essential oils of Chukrasia tabularis and Melia dubia were tested for their antimicrobial activity against ten different pathogenic microorganisms responsible for human pathologies using standard antimicrobial assays. Chukrasia tabularis leaf oil exhibited strong antibiotic activities against Proteus vulgaris and Fusarium oxysporum and did not show any activity against the tested bacteria. Melia dubia leaf essential oil exhibited bacteriostatic and fungistatic activities against Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae and Fusarium oxysporum and Candida albicans respectively. The inhibitory activities of both essential oils are comparable with that of respective standards. Copyright © 2003 John Wiley & Sons, Ltd.