bluuebunny/crossref_metadata_2025 huggingface dataset:
Model selection in canonical correlation analysis (CCA) using Bayesian model averaging
Authors: Noble Robert , Smith Eric P. , Ye Keying
Published: May 2004

Understanding the relationship between ecological indicators and environmental stressors is difficult. One problem is that the environmental data often consist of a large number of variables. The relationship between ecological data and environmental data is investigated using canonical correlation analysis with Bayesian model averaging used to identify important variables. A set of data from Ohio, U.S.A., is studied. Activation probabilities are used to indicate the important ecological indicators and environmental variables. A plot of model coefficients adjusted by activation probabilities is used to indicate variables that are important to canonical correlation axes. Copyright © 2004 John Wiley & Sons, Ltd.
Quantifying the effects of dynamical noise on the predictability of a simple ecosystem model
Authors: Bailey Barbara A. , Doney Scott C. , Lima Ivan D.
Published: May 2004

The need to understand the effects of anthropogenic perturbations on ocean biology has renewed interest in ecosystem and biogeochemical models in recent years. We develop a nonlinear time series approach to quantify the effects of different types of noise on ecosystem dynamics. Different types of noise can alter the local predictability of the system, induce qualitative regime shifts in model dynamics, and destroy (create) internal nonlinear oscillations and chaos. The ecosystem model we use in our article is a model of plankton dynamics and nitrogen cycling. It is a compartmental model (NPZD) consisting of compartments for nitrogen (N), phytoplankton (P), zooplankton (Z), and detritus (D). The flows or intercompartmental exchanges are modeled as a nonlinear system of four first‐order differential equations. The types of noise of interest are both independent and correlated. Because the noise is an integral part of the system's dynamics, a nonlinear time series approach is used to quantify the dynamics and predictability of the system. This involves fitting neural network models and estimating dynamical system quantities of interest such as global and local Lyapunov exponents, along with measures of uncertainty for these estimates. Copyright © 2004 John Wiley & Sons, Ltd.
Genetic tuning of a power system stabilizer
Authors: Sundareswaran K. , Razia Begum S.
Published: May 2004

This paper presents a novel method for the design of a Power System Stabilizer (PSS) using a Genetic Algorithm (GA). A generalized controller is considered and the parameters are tuned by redrafting the problem as an optimization task and the steps of the GA are applied for the solution. The simulation results indicate the superior performance of a genetic tuned controller over a conventional PSS. Copyright © 2004 John Wiley & Sons, Ltd.
Evaluation of a new proposal for an arcing fault detection method based on wavelet packet analysis
Authors: Lazkano Andoni , Ruiz Jesus , Aramendi Elisabete , Leturiondo Luis A.
Published: May 2004

This paper presents a new proposal for detection of arcing faults and evaluates the detection rate and the security level of the proposed method. This method is based on analysis of three‐phase unbalanced current, easily accessible feeder 3I0, using decomposition of the signal by means of wavelet transform techniques. Combining both temporal and frequency localizing properties, criteria are set in order to detect electric arc existence related to high impedance faults. The method has been tested with signals from staged fault records, normal condition records and substation event records. The test results show that the proposal is a satisfactory fault detection method and the relevant results are presented. Copyright © 2004 John Wiley & Sons, Ltd.
Influence of moisture and partial discharges on the degradation of high‐voltage surge arresters
Authors: Chrzan Krystian Leonard
Published: May 2004

This paper reports the influence of moisture and internal partial discharges on the degradation of metal oxide varistors in high‐voltage surge arresters. Both factors cause an increase in the varistor current under the operating voltage. This phenomenon is dangerous and can cause a total outage of the metal oxide arrester. In the field the moisture ingress can lead to internal discharges. Owing to recovery processes the changes in the voltage–current characteristics of varistors caused by moisture or partial discharges decrease in dry and partial discharge free conditions. The interesting behaviour of some varistors which were degraded by partial discharges was observed. Copyright © 2004 John Wiley & Sons, Ltd.
SF6 post‐arc recovery characteristics
Authors: Spiliopoulos I.
Published: May 2004

In SF6 circuit breakers, the result of the interruption, during the dielectric post‐arc phase, depends on the capability of the arcing region to withstand the applied recovery voltage. An idealized model breaker experiment is designed to investigate the SF6 recovery characteristics minimizing the effect of various factors such as metal vapor pollution, arc roots stagnation and gas‐flow modifications. The gas heating is obtained by a power arc in movement. The experimental simulation of the interruption allows the study of the gas recovery behavior as a function of the decaying plasma properties. The so‐obtained recovery characteristics exhibit distinct phases with recovery time increment and also dependencies on geometrical and electrical test parameters. Copyright © 2004 John Wiley & Sons, Ltd.
Sacrococcygeal chordomas in patients with tuberous sclerosis complex show somatic loss of TSC1 or TSC2
Authors: Lee‐Jones Lisa , Aligianis Irene , Davies Peter A. , Puga Ana , Farndon Peter A. , Stemmer‐Rachamimov Anat , Ramesh Vijaya , Sampson Julian R.
Published: May 2004

Chordomas are rare sacrococcygeal/sacral, sphenooccipital/clivus, and spinal tumors whose molecular etiology remains relatively understudied. As several anecdotal reports had described chordomas in individuals with tuberous sclerosis complex (TSC), a multisystem hamartoma syndrome, we hypothesized that the genes that cause TSC may have an etiological role in chordomas. In two cases of sacrococcygeal chordomas in individuals with TSC, one with a germ‐line TSC2 mutation and the other with a germ‐line TSC1 mutation, we confirmed somatic inactivation of the corresponding wild‐type allele by loss of heterozygosity analysis and immunohistochemistry. These data provide the first evidence of a pathogenic role by TSC genes in sacrococcygeal chordomas. © 2004 Wiley‐Liss, Inc.
Analysis of cytogenetic alterations in stage III serous ovarian adenocarcinoma reveals a heterogeneous group regarding survival, surgical outcome, and substage
Authors: Partheen Karolina , Levan Kristina , Österberg Lovisa , Helou Khalil , Horvath György
Published: May 2004

Ovarian cancer is the leading cause of death among patients with gynecological cancers, but the biology of these tumors is still among the least understood of all major human malignancies. In this study, comparative genomic hybridization was used to determine chromosomal alterations in 98 stage III serous papillary adenocarcinomas. The tumors were grouped according to survival and the main prognostic factors stage and surgical outcome. There were chromosomal imbalances that were significantly more common in tumors from patients who died than in tumors from patients who survived: gains of 1q24–qter and losses of 4p, 4q31.1–qter, 5q12–q22, 8p, 16q, and X. Furthermore, we observed that gains of 8q23–8q24.2 and losses of 4p, 4q13–4q26, 4q31.1–qter, 5q12–q22, 8p, and 16q were significantly more common in tumors from patients with macroscopic residual tumor after primary surgery, compared to tumors from those who had undergone radical surgery. Gains of 3q13.3–qter, 6p, 7q21–q31, and 11q13–q23 and losses of 4q31.1–qter and 16q were more common in stage IIIc tumors than in stage IIIa+b tumors. On the basis of our results, we suggest that there are biological differences among the groups mentioned above and that absence of chromosomal aberrations in specific regions predicts a good clinical outcome for individual patients. © 2004 Wiley‐Liss, Inc.
Cytogenetic changes in nonmalignant breast tissue
Authors: Steinarsdóttir Margrét , Jónasson Jón Gunnlaugur , Viđarsson Hilmar , Júlíusdóttir Hildur , Hauksdóttir Halla , Ögmundsdóttir Helga M.
Published: May 2004

Cytogenetic changes are common in breast cancer and have also been described in fibroadenomas and fibrocystic disease, but not in histologically normal breast tissue. Cytogenetic analysis was performed on nonmalignant breast tissue from benign breast lumps (n = 8), reduction mammoplasties (n = 31), and grossly nontumorous tissue from cancerous breasts (n = 84), using standard techniques and G‐banding. All samples were reviewed histologically. Clonal chromosomal changes were found in three of eight benign breast tumors (38%). Of the reduction mammoplasties, 17 samples contained nonproliferative changes, and three of these (18%) showed a clonal deletion of 3p. No pathology was identified in the other 14 samples, of which one (7%) contained two clonal changes, apparently balanced translocations. Of nontumorous tissues from cancerous breasts, 15 (18%) showed clonal chromosomal abnormalities. Five of these samples were histologically normal. Two clones were identical to those found in the corresponding cancer. In 18 additional samples, single cells were detected with the same change as that seen in clones or single cells in the cancer. Only 4 of these 20 samples contained detectable cancer cells. Clonal abnormalities found in two or more samples included trisomies X, 7, and 20 and monosomies 19 and 18. Clonal changes were not significantly more frequent in proliferative than in nonproliferative lesions. The Icelandic BRCA2 founder mutation, 999del5, was detected in four samples, all histologically normal, two of which had clonal chromosomal abnormalities. In conclusion, clonal chromosomal changes are not infrequent in nonmalignant breast tissue and can be detected even in the absence of histological abnormalities. © 2004 Wiley‐Liss, Inc.
Insertions generating the 5′RUNX1/3′CBFA2T1 gene in acute myeloid leukemia cases show variable breakpoints
Authors: Specchia Giorgina , Albano Francesco , Anelli Luisa , Zagaria Antonella , Liso Arcangelo , Starza Roberta La , Mancini Marco , Sebastio Lucia , Giugliano Emilia , Saglio Giuseppe , Liso Vincenzo , Rocchi Mariano
Published: May 2004

Translocation t(8;21)(q22;q22) is a common karyotypic abnormality detected in about 15% of acute myeloid leukemia (AML) cases. The rearrangement results in fusion of the RUNX1 (also known as AML1) and CBFA2T1 (also known as ETO) genes, generating a 5′RUNX1/3′CBFA2T1 transcriptionally active fusion gene on derivative chromosome 8, but some cases with ins(21;8) and ins(8;21) have been observed. However, a detailed breakpoint characterization of the insertion events has never been reported. In the present article, we describe six insertion events among 82 (7.3%) AML cases characterized by the RUNX1/CBFA2T1 fusion. Using FISH experiments with appropriate bacterial artificial chromosome (BAC) and P1 artificial chromosome (PAC) probes, we were able to perform a detailed molecular cytogenetic characterization of one case with ins(8;21) and five with ins(21;8). Our analysis revealed that insertions generating the 5′RUNX1/3′CBFA2T1 gene showed variable breakpoints; the size of the inserted elements ranged from 2.4 to 44 Mb. © 2004 Wiley‐Liss, Inc.
Diffusion kinetic study of cadmium(II) biosorption by Aeromonas caviae
Authors: Loukidou Maria X , Karapantsios Thodoris D , Zouboulis Anastasios I , Matis Kostas A
Published: May 2004

The removal of cadmium from aqueous solution by sorption on Aeromonas caviae particles was investigated in a well‐stirred batch reactor. Equilibrium and kinetic experiments were performed at various initial bulk concentrations, biomass loads and temperatures. Biosorption equilibrium was established in about 1 h and biosorption was well described by the Langmuir and Freundlich biosorption isotherms. The maximum biosorption capacity was found as 155.32 mg Cd(II) g−1 at 20 °C. The obtained sorption capacity is appreciably high for most experimental conditions; so A caviae may be considered as a suitable biosorbent for the removal of cadmium. Moreover, the sorption rate of cadmium onto A caviae particles was particularly sensitive to initial bulk concentration and solid load. A detailed analysis was conducted, examining several diffusion (external and intraparticle) kinetic models in order to identify a suitable rate expression. The results are discussed and indicate that biosorption of cadmium is a complex process that is described more correctly by more than one model. Copyright © 2004 Society of Chemical Industry
Solvent extraction separation of titanium(IV), vanadium(V) and iron(III) from simulated waste chloride liquors of titanium minerals processing industry by the trialkylphosphine oxide Cyanex 923
Authors: Narayanan Remya P , Lakshmipathy Reddy M
Published: May 2004

The solvent extraction of magnesium(II), aluminium(III), titanium(IV), vanadium(V), chromium(III), manganese(II) and iron(III) from hydrochloric acid solutions has been investigated using the trialkylphosphine oxide Cyanex 923 (TRPO) in kerosene as extractant. The results demonstrate that titanium(IV), vanadium(V) and iron(III) are extracted into kerosene as TiOCl2·2TRPO, VO2Cl·TRPO and HFeCl4·2TRPO, respectively. On the other hand magnesium(II), aluminium(III), chromium(III) and manganese(II) are not extracted with TRPO from hydrochloric acid solutions (1.0–4.0 mol dm−3) under the experimental conditions. IR spectral studies of the extracted complexes were further used to clarify the nature of the extracted complexes. The effect of the diluent on the extraction of titanium(IV), vanadium(V) and iron(III) has been studied and correlated with the dielectric constant. The loading capacity of the TRPO system has been evaluated and the potential for the separation and recovery of titanium(IV), vanadium(V) and iron(III) from simulated waste chloride liquors of the titanium minerals processing industry has been assessed. Copyright © 2004 Society of Chemical Industry
Recombination radiation from organic solids
Authors: Kalinowski Jan
Published: May 2004

The recombination radiation from organic solids, defined as the light emission following the fusion of oppositely charged carriers into an electrically neutral state, is discussed as a phenomenon underlying the function of organic light‐emitting diodes (LEDs). Its intensity and spectral range depend on the population and nature of the emissive states, which differ, in general, from those created using light. These differences are pointed out and shown to be a result of the reverse pathways of the mutual transformation of localized molecular excitons and coulombically‐correlated charge‐pair excited states formed either by photoexcitation or electron‐hole recombination. Spectral features of the radiation produced by the recombination of statistically independent charge carriers are discussed in terms of two molecules‐based excited states like excimers or electromers in single‐component materials and exciplexes or electroplexes in multicomponent materials. Consequences for optical and electrical characteristics of organic LEDs are discussed and illustrated by examples. Progress in the fundamental and applied research may be expected based on properties of recombination‐produced electronic excited states.
Charge transfer processes and environmental degrees of freedom: cooperativity and non‐linearity
Authors: Painelli Anna , Terenziani Francesca
Published: May 2004

To investigate supramolecular effects in samples with high concentration of push‐pull chromophores, we propose a model for interacting polar and polarizable molecules. Each molecule is described in terms of the same two‐state picture successfully adopted to model solvated chromophores and electrostatic interactions among different chromophores are introduced. Important supramolecular effects are observed even at the lowest mean‐field level, showing up the possibility of tuning molecular polarity from the neutral to the zwitterionic regime or vice versa. Supramolecular effects in excitation spectra are more complex. Here we demonstrate large supramolecular effects beyond mean‐field in static optical responses.
Spectroscopic studies of charge‐ordering system in organic conductors
Authors: Yakushi K. , Yamamoto K. , Świetlik R. , Wojciechowski R. , Suzuki K. , Kawamoto T. , Mori T. , Misaki Y. , Tanaka K.
Published: May 2004

Charge localization generates a non‐uniform charge distribution in some organic conductors. Phase transitions accompanying such a localization of charge are studied by using infrared and Raman spectroscopy. We first introduce θ‐(BEDT‐TTF)2MM′(SCN)4 (M=Rb, Cs, Tl; M′=Zn, Co) as typical examples of a charge‐ordering system, where BEDT‐TTF is bis(ethylenedithio)tetrathiafulvalene. We apply the same spectroscopic technique to α′‐(BEDT‐TTF)2IBr2, θ‐(BDT‐TTF)2Cu(NCS)2, and (TTM‐TTP)I3, which show the phase transitions from low‐resistivity to high‐resistivity state, where TTM‐TTP is 2,5‐bis[4,5‐bis(methylsulfonyl)‐1,3‐dithiol‐2‐ylidene]‐1,3,4,6‐tetrathiapentalene.
Electrical and spectral properties of organic salts formed from BEDT‐TTF and magnetic anions
Authors: Graja Andrzej , Łapiński Andrzej , Starodub Vladimir A.
Published: May 2004

Spectral and electrical investigations of the semiconducting (BEDT‐TTF)2W6O19 and the metal‐like (BEDT‐TTF)6(Mo8O26)(DMF)3 salts were performed. The vibrational and electronic spectra of the crystalline samples were analysed and assignment of the vibrational features was proposed. The temperature evolution of the vibrational spectra of the (BEDT‐TTF)2W6O19 salt was discussed.
Carbon papers with conductive polymer coatings for use in solid‐state supercapacitors
Authors: White Andrew , Slade Robert
Published: May 2004

Conductive polymer‐coated carbon papers have been fabricated through polymerisation of pyrrole‐based monomers oxidised with various heteropolyacids. Smooth surfaces are obtained when multiple coatings are applied to the carbon surface and give good contact with the Nafion® electrolyte. Cyclic voltammetry was used to study the electrodes and a.c. impedance and charge / discharge cycling was used to study membrane electrode assemblies (MEA). MEAs were fabricated using a hot‐press technique.
Polypyrrole electrodeposition on inorganic semiconductors CuInSe2 and CuInS2 for photovoltaic applications
Authors: Bereznev Sergei , Konovalov Igor , Kois Julia , Mellikov Enn , Öpik Andres
Published: May 2004

Thin polypyrrole (PPy) layers with an average thickness of about 0.5 μm were deposited, using potentiostatic and galvanostatic techniques, on CuInSe2 (CISe) structures prepared electrochemically on glass/ITO substrates and on CuInS2 (CIS) structures fabricated on Cu tape substrates. The polymer layer of p‐type is considered as an alternative to the traditional buffer layer and window layer in the conventional cell structure. The deposition proceeded from an aqueous solution containing sodium naphthalene‐2‐sulfonate as a dopant. In order to prepare stable PPy films of high quality with a good adherence to the surface of inorganic semiconductors CIS and CISe, the optimal concentrations of reagents, current densities and electrodepositing potentials were selected experimentally. Electrochemical polymerization of pyrrole to PPy on CIS surfaces is faster under white light irradiation and the polymerisation starts at lower potential than in the dark. Significant photovoltage and photocurrent of the fabricated CISe/PPy and CIS/PPy structures have been observed under standard white light illumination.
Thermally stimulated carrier transport due to stepwise sample heating
Authors: Tomaszewicz Władysław
Published: May 2004

The article concerns non‐isothermal dispersive carrier transport in an insulating solid with traps. The approximate solutions of transport equations derived previously are extended to the case of stepwise sample heating. The specific features of thermally stimulated currents (TSCs) can be attributed to non‐linear dependence of the demarcation level on temperature. In particular, the initial TSC rise has a thermally activated character where activation energy equals to the demarcation energy at the end of previous heating cycle. The accuracy of the formulae describing TSCs is verified by Monte Carlo calculations for Gaussian trap distribution.
Current‐voltage characteristics of thin poly(biphenyl‐4‐ylphthalide) films
Authors: Bunakov Andrei , Lachinov Aleksei , Salikhov Renat
Published: May 2004

The paper considers the features of the charge transport near to the threshold of the transition of polymer films to the high conductive state, induced by a small uniaxial pressure. The problem has not been solved so far, how the energy structure of a wide‐band‐gap organic dielectric varies near this threshold. The current‐voltage characteristics of poly(biphenyl‐4‐ylphthalide) films at different uniaxial pressures were measured and analyzed. The interpretation of the obtained results is carried out within the framework of the space charge limited conduction model. The estimation of the injection model of transport parameters such as the charge carrier mobility and concentration, trapping state concentration and others are carried out. The analysis of the obtained results allows to make the following preliminary conclusion. Pressure increase promotes formation of a narrow trap band near the quasi‐Fermi level resulting from the increase in the injection. This can give rise to a sharp magnification of the charge carrier mobility and even transition to the metallic state.
Photochromic liquid crystalline structures containing azobenzene moieties
Authors: Studenovský Martin , Sedláková Zdenka , Wang Geng , Nešpůrek Stanislav , Janus Krzysztof , Boiko Olexandr P. , Kajzar Francois
Published: May 2004

Novel liquid crystalline photochromic materials of the type 4‐R‐C6H4‐N=N‐C6H4‐O(CH2)n‐N(CH2CH2OH)2, where R is NO2, H, CN, O‐n‐C8H17, phenyl, 4‐O2NC6H4, were prepared. Some of them are photoconductive. These materials were used for the preparation of light‐sensitive polymers in which the photoactive moieties were attached to polyurethane chain. Photochromism of these compounds is based on trans‐cis isomerization of azobenzene group. An example of the photochromic activity is presented on solid solution of one material (R = O‐n‐C8H17, n = 5) in poly(methyl methacrylate) matrix.
Optical and dielectric properties of new azobenzene copolyethers embedded in polymer matrices
Authors: Strat M. , Strat G. , Scutaru V. , Gurlui S. , Grecu I.
Published: May 2004

A new group of photochromic azobenzene copolyethers was synthesized. Their photochomic and dielectric properties were studied in poly(vinyl alcohol) and poly(methyl methacrylate) matrices.
Polarized electroluminescence from bilayer structures
Authors: Wang Geng , Nešpůrek Stanislav , Rakušan Jan , Karásková Marie , Schauer František , Brehmer Ludwig
Published: May 2004

The photoalignment ability of poly[methyl(phenyl)silylene] (PMPSi) films makes it possible to use them as hole‐transporting substrates for the preparation of organic oriented films. A PMPSi layer prepared by spin coating was irradiated, after drying, with linearly polarized UV light. Then, water‐soluble hydroxyaluminium phthalocyaninesulfonate [Al(OH)Pc(SO3Na)1−2] was deposited by casting. The cell ITO/PMPSi/Al(OH)Pc(SO3Na)1−2/Al showed non‐linear current‐voltage characteristics. For applied voltages higher than 10 V, polarized electroluminescence was observed. Its spectral characteristic consisted of two peaks with maxima at about 320 and 700 nm; their polarized anisotropies REL= Φ∥ / Φ⟂ were ca. 15 and 0.5, respectively.
Temperature‐ and humidity‐related degradation of conducting polyaniline films
Authors: Tobolková Eva , Prokeš Jan , Křivka Ivo , Trchová Miroslava , Stejskal Jaroslav
Published: May 2004

The time dependence of dc conductivity of conducting polyaniline films was measured in relation to temperature and relative humidity of the environment. Optical and structural properties of the samples were checked using Fourier transform infrared (FTIR) spectroscopy.
Charge transport in polyaniline doped with 3‐nitro‐1,2,4‐triazol‐5(4H)‐one
Authors: Starykov Oleksiy , Prokeš Jan , Křivka Ivo , Stejskal Jaroslav
Published: May 2004

Polyaniline (PANI) base was protonated in aqueous solutions of an organic acid, 3‐nitro‐1,2,4‐triazol‐5(4H)‐one (NTO). The temperature dependence of DC conductivity of PANI‐NTO seems to correspond to the theory of variable range hopping (VRH) in three dimensions. The frequency dependence of AC conductivity also reflects the hopping nature of mobile charges. The activation energy for the polymers with protonation degree above 0.12 remains constant with increasing dopant concentration and DC conductivity. The value of this constant may correspond to the energy needed for the ionization of dopant counterion. The fit of the electric relaxation function to the stretched exponential function ϕ(t) = exp[−(t/τ)β] gives the stretch parameter β about 0.35, which shows that the distribution of relaxation times is broad and indicates a high inhomogeneity in the distribution of a dopant.
Phase transitions in poly(heptane‐1,7‐diyl biphenyl‐4,4′‐dicarboxylate). SAXS, WAXS and DSC study
Authors: Todorova Ginka , Pérez Ernesto , Marugán Mónica M. , Kresteva Manya
Published: May 2004

The main‐chain thermotropic liquid‐crystalline poly(heptane‐1,7‐diyl biphenyl‐4,4′‐dicarboxylate) (P7MB) was investigated by time‐resolved small‐angle X‐ray scattering (SAXS), wide‐angle X‐ray scattering (WAXS), and differential scanning calorimerty (DSC). Nonisothermal crystallisation with different rates of cooling and heating was used. On cooling, two phase transitions are observed, isotropic melt ‐ smectic (I‐Sm) and Sm‐ three‐dimensional crystalline structure (Sm‐Cr), whereas on heating only one transition is observed, Cr‐I transition. The transition enthalpies were calculated. Temperature dependences of d‐spacings of all crystalline peaks and of the peak observed at high values of scattering vector in the SAXS region were derived. The temperature dependence of the degree of crystallinity was established, based on the integrated intensities of the crystalline peaks and amorphous halo in WAXS.
Polydiacetylene nanowires in ultrathin films
Authors: Alloisio Marina , Cavallo Dina , Dell'Erba Carlo , Cuniberti Carla , Dellepiane Giovanna , Giorgetti Emilia , Margheri Giancarlo , Sottini Stefano
Published: May 2004

In this paper the results of studies carried out on thin films of new poly[bis(carbazol‐9‐ylmethyl)diacetylene]s (PCDAs) are reported. The preparation of the films has required clever synthesis to make processable the conjugated polymers without degrading their optoelectronic properties. To this end, the parent poly(diacetylene), (polyDCHD), has been modified by introducing long alkyl or acyl chains in the 3 and 6 positions of the carbazole rings. Electronic absorption spectra and linear and nonlinear optical characterization of three types of PCDAs are reported and compared.
Organic electroluminescent devices containing phosphorescent molecules in molecularly doped hole transporting layer
Authors: Stampor Waldemar , Mężyk Jakub , Kalinowski Jan , Cocchi Massimo , Virgili Dalia , Fattori Valeria , Di Marco Piergiulio
Published: May 2004

We demonstrate high‐efficient simple electrophosphorescent devices comprised of tris{4‐[N‐(3‐methylphenyl)anilino]phenyl}amine (m‐MTDATA) dispersed in a polycarbonate (PC) matrix as a hole‐transporting layer (HTL), and 2‐(biphenyl‐4‐yl)‐5‐(4‐tert‐butylphenyl)‐1,3,4‐oxadiazole (PBD) as an electron‐transporting layer (ETL). The HTL doped with a complex phosphor fac‐tris(2‐phenylpyridine)iridium, [Ir(ppy)3], and/or 5,6,11,12‐tetraphenyltetracene (rubrene) fluorescent dye is shown to act as an emitter. Devices containing [Ir(ppy)3] as a single HTL dopant show the highest external quantum efficiency (QE) reaching 9 % (photon/electron) due to direct electron‐hole recombination on phosphorescent [Ir(ppy)3]. A decrease in QE of one order of magnitude at high current densities is observed in all devices. Addition of rubrene to [Ir(ppy)3]‐doped devices shifts the maximum QE towards larger current densities.
Modification of poly(styrene‐alt‐maleic anhydride) with 1,3,4‐oxadiazole units for electroluminescent devices
Authors: Aldea Gabriela , Výprachtický Drahomír , Cimrová Věra
Published: May 2004

New copolymers of poly(styrene‐alt‐maleic anhydride) (PSMA) modified with 2‐(4‐aminophenyl)‐5‐(biphenyl‐4‐yl)‐1,3,4‐oxadiazole and hexylamine were prepared. The copolymers, characterized by UV‐vis and FT IR spectroscopy, reached 1.22 mol % of the oxadiazole units relative to anhydride groups at the maximum (PSMA‐4). Electric and optical properties of the copolymers were studied. The currents obtained depend strongly on the content of oxadiazole units in the copolymers. Currents measured in PSMA‐4 were more than two orders of magnitude higher than those measured in the copolymers without oxadiazole. Using polymer blends made of poly(9,9‐dihexadecylfluorene‐2,7‐diyl) and PSMA‐4, blue light‐emitting devices were fabricated and their photoluminescence and electroluminescence spectra were measured.
Photosensitive layers of TiO2/polythiophene composites prepared by electrodeposition
Authors: Pfleger J. , Pavlík M. , Hebestreit N. , Plieth W.
Published: May 2004

We adopted an electrophoretic deposition method for the preparation of thin layers of insoluble composite nanoparticles composed of TiO2 core and about 2 nm thick shell of polythiophene, prepared by oxidative polymerization of thiophene. The reduced form of TiO2‐polythiophene composite material was deposited on the conductive surface from an ultrasonically generated microdispersion. Varying the dispersion media, applied voltage and the electrode arrangement made it possible to control the quality and morphology of the films. Compact semitransparent films deposited on ITO electrodes, suitable for photoelectrical measurements, were obtained within short deposition times.
Diagnosis and management of pergolide‐induced fibrosis
Authors: Agarwal Pinky , Fahn Stanley , Frucht Steven J.
Published: May 2004

We report on 2 patients treated with pergolide, 1 of whom developed pleural fibrosis and the other retroperitoneal fibrosis. In both cases, an extensive diagnostic evaluation and surgical intervention were required to reach a diagnosis. Based on our experience with these patients and a review of cases of pergolide‐induced fibrosis in the English‐language literature, we propose guidelines for the diagnosis and management of this rare complication. © 2004 Movement Disorder Society
Solid‐state lasers based on inorganic–organic hybrid materials obtained by combined sol–gel polymer technology
Authors: Reisfeld R. , Weiss A. , Saraidarov T. , Yariv E. , Ishchenko A. A.
Published: May 2004

Sol–gel glass matrices in which organic laser dyes are embedded can be used as the gain medium in solid‐state, continuously tunable lasers. Such lasers are very simple to construct, and potentially very compact and efficient. Unlike the commonly used liquid dye laser systems, solid‐state dye lasers can be made mechanically robust and portable. In this article, the development of sol–gel/dye lasers, including the sol–gel technology, dye properties, and laser operation, is reviewed. In addition, new solid‐state hosts (such as polyurethane/silica ORMOSILs), additional organic dyes (cyanines), and new studies on the stability of the dyes are presented. Copyright © 2004 John Wiley & Sons, Ltd.
Synthesis and evaluation as a visible‐light polymerization photoinitiator of a new dye‐linked bis(trichloromethyl)‐1,3,5‐triazine
Authors: Kawamura Koichi , Kato Kunimasa
Published: May 2004

A dye‐linked initiator consisting of a merocyanine dye, which has an absorption maximum at 460 nm, and a substituted bis(trichloromethyl)‐1,3,5‐triazine initiator was prepared in order to achieve an efficient photopolymerization in a visible‐light region. The spectroscopic studies clearly showed that the dye‐linked initiator exhibit a marked increase in the efficiency of fluorescence quenching than a simple mixture of the dye/initiator. These results are reasonably explained in terms of the efficiency of electron transfer between the dye and the initiator. The relative photoinitiating efficiency of dye‐linked initiators in photopolymerization of acrylate monomers was evaluated and the results clearly indicated that the dye‐linked photoinitiator exhibited a marked increase in the photoinitiating efficiency of photopolymerization of acrylates compared to a simple mixture of the dye/initiator in photopolymer coatings particularly at a lower concentration of the initiator. This was explained in terms of the active quenching sphere of the dye/initiator system. Superior photosensitivity in the linked compound at a lower concentration indicates that this would be particularly useful as a visible‐light photoinitiator in holographic‐recording photopolymers. Copyright © 2004 John Wiley & Sons, Ltd.
Investigation of the tensile properties of “epoxy resin‐monomer” systems using cationic UV‐crosslinkable blends
Authors: Czech Zbigniew , Urbala Magdalena , Martysz Dagmara
Published: May 2004

The compatibility of cycloaliphatic and aromatic multifunctional epoxides with several epoxide resins allows the development of a wide range of cationic radiation‐curable formulations. The influence of different “epoxide resin‐monomer” systems UV‐cured in the presence of suitable cationic photoinitiators on the resulting physicochemical film properties was studied, and the results are stated. Copyright © 2004 John Wiley & Sons, Ltd.
Initial uptake and evidence of safe prescribing practice with Buproprion (Zyban®)
Authors: Williams D. , Bennett K. , Heery A. , Feely J.
Published: May 2004

Purpose

To study the effect of safety concerns and the introduction of freely available nicotine replacement therapy (NRT) on the prescribing of Buproprion within the General Medical Services (GMS) scheme in Ireland.

Methods

Using the state‐supported GMS prescription database in Ireland, we identified 8166 patients who were prescribed Buproprion and 18 450 patients who were prescribed NRT over a 12‐month‐period.

Results

A decline in the prescribing of Buproprion was noted which coincided with concerns regarding the safety of the drug but which preceded the introduction of NRT to the GMS. Furthermore, patients who were prescribed Buproprion were less likely to be co‐prescribed potentially interacting drugs (odds ratio (OR): 0.48, 95% confidence intervals (CI): 0.42, 0.54) or drugs known to reduce seizure threshold (OR: 0.63, 95% CI: 0.6, 0.67) indicating good prescribing practice. Patients aged 65 years or more were less likely to be prescribed any form of smoking cessation therapy compared with those aged <65 years (OR: 0.23, 95% CI: 0.22–0.24) indicating that such therapy was targeted at those most likely to benefit.

Conclusions

We provide evidence that prescribers exercised caution in the prescription of Buproprion and were likely to have been influenced both by the safety concerns and the introduction of freely available NRT to the GMS population. Copyright © 2003 John Wiley & Sons, Ltd.
Synthesis, characterization, and biological activity of [2‐oxo‐2‐(4‐acetyl) phenyl amino] ethylene methacrylate and its derivatives
Authors: Erol Ibrahim
Published: May 2004

A new type of methacrylate monomer, [2‐oxo‐2‐(4‐acetyl) phenyl amino] ethylene methacrylate (APEMA), was synthesized. The oxime, 2,4‐dinitrophenylhydrazone, and thiosemicarbazone derivatives of poly{[2‐oxo‐2‐(4‐acetyl) phenyl amino] ethylene methacrylate} [poly(APEMA)] were prepared with hydroxylamine hydrochloride, 2,4‐dinitrophenylhydrazine, and thiosemicarbazone hydrochloride, respectively. The radical homopolymerization of APEMA was performed at 65 °C in a 1,4‐dioxane solution with benzoyl peroxide as an initiator. The monomer and its homopolymer were characterized with Fourier transform infrared and NMR techniques. The thermal stabilities of poly(APEMA) and its derivatives were investigated with thermogravimetric analysis and differential scanning calorimetry. The ultraviolet stability of the polymers were compared. The solubility and inherent viscosity of the polymers were also determined. The number‐average and weight‐average molecular weights and polydispersity index of the polymers were determined with gel permeation chromatography. The antibacterial and antifungal effects of the monomer and the polymer and its derivatives were also investigated on various bacteria and fungi. The activation energies of the thermal degradation of the polymers were calculated with the Ozawa method. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3157–3169, 2004
Preparation and characterization of multifunctional maleimide macromonomers and their cured resins
Authors: Liu Ying‐Ling , Wang Yao‐Hsuan
Published: May 2004

Multifunctional compounds with pendent and terminal maleimide groups were prepared through the reaction of 4‐maleimidobenzoic acid and 5‐maleimidoisophthalic acid with diglycidyl ether of bisphenol A. The ratios of the pendent maleimide groups to the terminal maleimide groups in the obtained compounds were varied to tailor the chain length and properties of the maleimide compounds. The maleimide group ratios, determined from differential scanning calorimetry, showed good coincidence with the values calculated from the charged monomer amounts. The good solubility and low softening points of the maleimide compounds indicated their good processability. High glass‐transition temperatures (220 °C) were observed for the cured resins because of the relatively high crosslinking density. The curing reaction, thermal stability, and degradation behavior of the resins were also studied with differential scanning calorimetry and thermogravimetric analysis. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3178–3188, 2004
Synthesis of novel polypyromellitimides with n‐alkyloxy side chains and their liquid‐crystal aligning property
Authors: Lee Seong Jun , Jung Jin Chul , Lee Seung Woo , Ree Moonhor
Published: May 2004

New well‐defined brush polypyromellitimides with n‐octyloxy and n‐dodecyloxy side chains were prepared by two‐step polycondensations of 3,6‐di(n‐alkyloxy)pyromellitic dianhydrides with various conventional aromatic diamines. Their structures and properties were investigated and compared with those of polyimides without the side chains. The alkyloxylated poly(amic acid)s had inherent viscosities of 0.45–1.09 dL/g. The polyimides showed enhanced solubility in organic solvents and had layered structures in the solid state. As the side‐chain length increased from n‐octyloxy to n‐dodecyloxy, the extent of layered structure formation increased, whereas the glass‐transition temperature and thermal resistance decreased. As for the liquid‐crystal (LC) aligning ability measured with 4‐n‐pentyl‐4′‐cyanobiphenyl on rubbed thin‐film surfaces, all the side‐chain polyimides revealed homogeneous LC alignment parallel to the rubbing direction with distinctively higher pretilt angles than those of the polyimides without the side chains. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3130–3142, 2004
Structure and properties of polyimide films during a far‐infrared‐induced imidization process
Authors: Xu Yi‐Kun , Zhan Mao‐Sheng , Wang Kai
Published: May 2004

The conversion of poly(amic acid) into polyimide (PI) was achieved with far‐infrared radiation (FIR) and conventional thermal treatments. The structure and properties of PI films during different stages of imidization were studied with Fourier transform infrared spectroscopy, weight‐loss analysis during imidization, tensile property measurements, and dynamic mechanical thermal analysis. The effects of the imidization degree, postimidization, and solvent on the thermal and mechanical properties of PI films were quantitatively investigated. The corresponding structural changes were also examined. The experimental results showed that the imidization process proceeded more quickly and more completely in an FIR oven than in a conventional oven. A prolonged FIR treatment at a lower temperature (25–100 °C) accelerated the imidization process. The tensile stress–strain curves had a fanlike distribution with the development of the FIR imidization process and a fishtail distribution with conventional thermal imidization. During FIR imidization, the best tensile properties were obtained at 340 °C, and thermooxidative degradation occurred at about 420 °C. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 2490–2501, 2004
Ethylenediamine as a liquid chemical reagent to probe hydrogen bonding and host‐guest interactions with crown ethers in an ion trap tandem mass spectrometer
Authors: Wu Hui‐Fen , Lin Pei‐Yi
Published: May 2004

Ethylenediamine (EDA) was used as a novel liquid chemical reagent to probe hydrogen bonding and host‐guest interactions with crown ether derivatives in an ion trap mass spectrometer (ITMS). Selective ion/molecule reaction product ions were generated by reactions of EDA with oxygenated and aza‐crown ethers. For the oxygenated crown ethers, glycols and dimethylglycols, ion/molecule reactions led to the formation of the protonated molecules ([M+H]+) and adduct ions including [M+30]+, [M+44]+ and [M+61]+. The aza‐crown ethers produced [M+H]+, [M+13]+ and [M+27]+ ions. Collisionally activated dissociation (CAD) experiments were applied to probe the binding strength of these ion/molecule reaction products. CAD results indicated that all these hydrogen‐bonding complexes are weakly bound except for the [M+44]+ ion of 18‐crown‐6, since all the complexes dissociate to the protonated polyether and/or protonated EDA. Fragmentation of the [M+H]+ ions under CAD conditions indicates the extensive covalent bond cleavage of the protonated crown ether skeleton. Copyright © 2004 John Wiley & Sons, Ltd.
Analytical characterization of a facile porous polymer monolithic trypsin microreactor enabling peptide mass mapping using mass spectrometry
Authors: Palm Anders K. , Novotny Milos V.
Published: May 2004

A simple and rapid single‐step method is presented to fabricate an enzyme reactor using trypsin immobilized on a macroporous polymer monolith. A reactor produced in a capillary format is ready to use within 1 h of preparation. The monomers making up the monolith, includingN‐acryloxysuccinimide for covalent immobilization of the enzyme, are mixed with trypsin and introduced into the column by capillary force for polymerization/immobilization. The enzyme activity from column‐to‐column is reproducible below 5% relative standard deviation (RSD), while the reactor is durable for at least 20 weeks when stored at room temperature. The apparent kinetic constants Vmaxand Kmare of value similar to those obtained by free trypsin in solution. Enzymatic digestion of proteins was shown to be feasible on a time‐scale of seconds and submicromolar concentrations enabling peptide mass mapping by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry. Copyright © 2004 John Wiley & Sons, Ltd.
Using the Impact of Event Scale to Evaluate Psychological Response to Being a Phenylketonuria Gene Carrier
Authors: Read Catherine Y.
Published: May 2004

The birth of a child with phenylketonuria (PKU) is almost always a shock to the parents, who are faced with the realities of caring for a child with special needs and the need to cope with the realization that they are obligate carriers of the responsible gene. The Impact of Event Scale (IES) was used to assess the psychological impact of being a PKU gene carrier on 83 parents of children with PKU. IES scores decreased significantly from the time of initial diagnosis of PKU to the current time. The magnitude of the psychological impact did not correlate with the age of the parent, the number of years since the diagnosis of PKU, or the health or development of the child. As more tests become available for detecting the presence of disease‐related genes, instruments such as the IES may prove useful in the evaluation of psychological responses to genetic information.
Das 22q11.2-Deletionssyndrom und seine Relevanz für die Kinder- und Jugendpsychiatrie
Authors: Briegel W. , Cohen M.
Published: May 2004

Zusammenfassung: Das 22q11.2-Deletionssyndrom ist das häufigste bekannte Mikrodeletionssyndrom beim Menschen. Betroffene Patienten können eine Vielzahl körperlicher Störungen zeigen, vor allem charakteristische dysmorphe Gesichtszüge, Herzfehler, Thymus- sowie strukturelle oder funktionelle Gaumenanomalien. Typisch sind auch deutliche Beeinträchtigungen der motorischen, sprachlichen, kognitiven und sozialen Entwicklung sowie psychiatrische Störungen. Nach dem aktuellen Forschungsstand treten bei Kindern und Jugendlichen mit einer Deletion 22q11.2 insbesondere Aktivitäts- und Aufmerksamkeitsstörungen, affektive Störungen sowie tiefgreifende Entwicklungsstörungen gehäuft auf. 2% aller schizophrenen Erkrankungen im Erwachsenenalter sollen durch eine Deletion 22q11.2 verursacht sein. Der Artikel gibt einen aktuellen Überblick über Ätiologie, körperliche Symptomatik, Entwicklungsaspekte und psychiatrische Komorbidität des 22q11.2-Deletionssyndroms. Es werden klinische Kriterien für die humangenetische Abklärung einer Deletion 22q11.2 bei Kindern und Jugendlichen mit psychiatrischen Störungen definiert. Außerdem werden Behandlungsmöglichkeiten für die beim 22q11.2-Deletionssyndrom häufigen psychiatrischen Störungen erörtert. Insgesamt wird bei psychisch kranken Kindern und Jugendlichen eine Deletion 22q11.2 bisher noch zu selten diagnostiziert - trotz ihrer klinischen Relevanz.
Double dayside detached auroras: TIMED/GUVI observations
Authors: Zhang Y. , Paxton L. J. , Meng C.‐I. , Morrison D. , Wolven B. , Kil H. , Christensen A. B.
Published: May 2004

On August 19, 2003, TIMED/GUVI detected, for the first time, two separated (double) dayside detached auroras (D‐DDA) simultaneously in all the GUVI channels, 121.6 nm, 135.6 nm, LBHS, and LBHL. The D‐DDA was located at magnetic latitudes around −57° and −63° (L shell 3.4 and 4.9) in the 0900–1030 MLT region. The high‐latitude part of the D‐DDA is much brighter than the low‐latitude part. DMSP particle observation indicates that the source of the D‐DDA is energetic (∼10 keV) precipitating protons/electrons from the ring current due to the solar wind dynamic pressure enhancements [Zhang et al., 2002] and/or northward turning of the IMF Bz. Observations of the D‐DDA provide the first single‐event evidence of multiple peaks in the statistical distribution of proton fluxes at energetic around and below 10 keV at low L‐shells [Milillo et al., 2001].
Data assimilation of ground‐level ozone in Europe with a Kalman filter and chemistry transport model
Authors: Hanea Remus G. , Velders Guus J. M. , Heemink Arnold
Published: May 2004

A Kalman filter coupled to the atmospheric chemistry transport model EUROS has been used to estimate the ozone concentrations in the boundary layer above Europe. Two Kalman filter algorithms, the reduced rank square root (RRSQRT) and the ensemble Kalman filter (ENKF), were implemented in this study. Both required, in general, a large number of EUROS model simulations for an assimilation. The observations consisted of hourly ozone data in a set of 135 ground‐based stations in Europe for the period, June 1996. Half of these stations were used for the assimilation and the other half only for validation of the results. The combination between data assimilation (Kalman filter) and the atmospheric chemistry transport model, EUROS, gave more accurate results for boundary layer ozone than the EUROS model or measurements used separately. The average difference between assimilated and measured ozone concentrations decreased from 27.4 to 20.5 μg m−3 for the average of the stations used for validation in Europe. Both algorithms tend to converge to about the same accuracy, with an increasing number of EUROS model runs. About 10–20 EUROS model calculations were found sufficient for a good assimilation. The results are supported by a number of simulations that also reveal a local character for the assimilation process.