bluuebunny/crossref_metadata_2025_split huggingface dataset:
Kinetics of refractive index changes in polymeric photochromic films
Authors: Ortyl Ewelina , Kucharski Stanisław 
Published: May 2004

AbstractMethacrylate copolymers containing, in side chain azobenzene groupings with heterocyclic sulfonamide substituents: N‐(2,6‐dimethylpyrimidin‐4‐yl)sulfamoyl (sulfisomidine) and N‐(5‐methylisoxazol‐3‐yl) sulfamoyl (sulfamethoxazole) were investigated. The materials undergo reversible trans‐cis isomerisation during illumination with light. This results in changes of dipole moment, polarizability and refractive index. Ellipsometric measurements showed a distinct decreasing refractive index during illumination with light corresponding to absorption band (ca. 450 nm). Depending on the polymer, the change of real part of refractive index in spin‐coated films was between 0.016 and 0.031. The dynamics of growth and decay of refractive index changes, was described by biexponential function approach.
Electrical conductivity of polycrystalline films of p‐sexiphenyl
Authors: Tkaczyk Stanislaw , Świątek Jozef 
Published: May 2004

AbstractIn this work the results of DC conductivity measurements of polycrystalline p‐sexiphenyl thin films are presented. The investigations concerned the effect of temperature, film thickness and electric field on the DC conductivity mechanism. The thickness of the investigated material varied from 0.2 to 2.5 μm. The measurements were carried out for different electrode polarities of the 0 ‐100 V voltage and at temperatures ranging from 15 to 325 K. Thin films of p‐sexiphenyl were obtained by controlled vacuum sublimation on BK‐7 glass substrate with gold and aluminium electrodes. Analyzing the obtained results we conclude that injection of the charge carrier from electrodes into the investigated material proceeds by thermionic emission and field emission and it is dependent on temperature and external electric field. The charge carrier transport is controlled by localized states (traps) in the forbidden energy gap. The activation energy calculated from formula ln I = f(1/kT) varied from kT for low temperature up to 1.0 eV.
Photovoltaic properties of tetracene and pentacene layers
Authors: Signerski Ryszard , Jarosz Grażyna , Godlewski Jan 
Published: May 2004

AbstractPhotovoltaic phenomenon in tetracene and pentacene layers evaporated under the same conditions onto a glass substrate and provided with the same couple of electrodes is investigated. Comparison of the results obtained for both organic materials makes it possible to conclude that in spite of differences in mechanisms of charge carrier generation, the values of photovoltaic parameters are very similar.
Lattice dynamics and electron‐phonon coupling in pentacene crystal structures
Authors: Masino Matteo , Girlando Alberto , Brillante Aldo , Farina Luca , Della Valle Raffaele Guido , Venuti Elisabetta 
Published: May 2004

AbstractThe crystal structures and lattice phonons of pentacene are computed by the quasi harmonic lattice dynamics (QHLD) method. From the eigenvectors of the low frequency phonons we calculate the e‐ph coupling constants due to the modulation of the transfer integrals. The transfer integrals are computed by the Hückel method and by the INDO/S Hamiltonian for all the nearest neighbor pentacene pairs in the ab crystal plane.
Dispersive and non‐dispersive hole transport in fluorene‐arylamine copolymers
Authors: Poplavskyy Dmitry , Nelson Jenny , Bradley Donal D.C. 
Published: May 2004

AbstractHole transport in two fluorene‐arylenediamine copolymers is studied by means of time‐of‐flight (ToF) and space‐charge‐limited dark‐injection (SCL DI) transient current methods. Non‐dispersive and dispersive hole transport is observed for a range of sample thicknesses, applied electric fields and temperatures.
Influence of morphological and conformational changes on the molecular mobility in poly(ethylene naphthalene‐2,6‐dicarboxylate)
Authors: Colombini Didier , Zouzou Noureddine , Martinez‐Vega Juan Jorge 
Published: May 2004

AbstractDynamic electric (DEA) and mechanical (DMA) analyses were combined to explore the relaxational processes in amorphous and semicrystalline poly(ethylene naphthalene‐2,6‐dicarboxylate) (PEN) samples. Differential scanning calorimetry measurements were carried out to investigate the crystallinity of the samples following isothermal annealing treatment at 443 K. The two secondary relaxations β and β*, the main α relaxation, as well as the ρ‐relaxational process, were revealed by both electric and mechanical viscoelastic responses of the PEN samples. DMA results clearly identified the above Tα loss factor peak, ρ, as a probe of the cold crystallization. However, the association of both DMA and DEA investigations pointed out that electric and non‐electric aspects might govern the ρ‐process.
Influence of carbazol‐9‐yl substitution in polysilanes on charge carrier trapping and recombination
Authors: Glowacki Ireneusz , Dobruchowska Ewa , Luszczynska Beata , Ulanski Jacek 
Published: May 2004

AbstractA series of poly{[3‐(carbazol‐9‐yl)propyl]silane‐co‐methylphenylsilane}s were investigated by optical absorption, photoluminescence and thermoluminescence measurements. It was found that the optical absorption bands of the carbazolyl side groups superimpose on those of the Si backbones in the ultraviolet range. This feature reduces photodegradability of Si‐Si bonds during UV irradiation. The TL spectra recorded in the 15 ‐ 325 K temperature range after photoexcitation at 15 K show that the carbazolyl side groups act as trapping sites in polysilanes. Increasing density of carbazolyl groups results in increasing population of deeper (ca. 150 meV) traps. Spectral analyses of the thermoluminescence at different temperatures are discussed and compared with analogous results for poly(9‐vinylcarbazole) (PVK). It is concluded that the monomeric mechanism of luminescence dominates at low temperatures while the excimeric mechanism prevails at higher temperatures, similarly to PVK.
Density‐of‐states function in metal‐free phthalocyanine: effect of exposure to chlorodifluoromethane
Authors: Zhivkov I. , Danev G. , Nešpůrek S. , Sworakowski J. 
Published: May 2004

AbstractChanges in the energy structure of local states during the exposure of metal‐free phthalocyanine films to chlorodifluoromethane were studied using the technique of thermomodulated space‐charge‐limited currents. The broadening of the energy distribution of the states is explained on the basis of charge‐dipole interactions.
Correlation between large polarons in molecular chains
Authors: Brizhik Larissa , Eremko Alexander 
Published: May 2004

AbstractWe studied few extra electrons in a molecular chain with respect of electron‐phonon coupling in the adiabatic approximation. It is shown that the lowest state of two extra electrons in a chain corresponds to the singlet bisoliton state with one deformational potential well. Two electrons with parallel spins form a localised triplet state, which corresponds to the two‐hump charge distribution function. Three extra electrons form an almost independent nonlinear superposition of a soliton and bisoliton states. In the case of four electrons, the two almost independent bisolitons are formed. These two states tend to separate in the chain at the maximal distance due to the Fermi repulsion, accounted for in the zero‐order adiabatic approximation. This repulsion is partly compensated by the attraction between the solitons due to their exchange with virtual phonons, described by the non‐adiabatic part of the Hamiltonian. The formation of solitons is characterised by the appearance of the bound soliton and bisoliton levels in the forbidden energy band. This constitutes the qualitative difference of the large polaron (soliton) states from the almost free electron states and small polaron states.
Organic electroluminescent devices using europium complex‐doped poly(N‐vinylcarbazole)
Authors: Li Tingxi , Fukuyama Hidehito , Yamagata Yoshinori , Lan Hsing‐Lin , Kido Junji 
Published: May 2004

AbstractElectroluminescence (EL) properties of europium (Eu) complex‐doped poly(N‐vinylcarbazole) (PVK) were investigated. A device structure of glass substrate/indium‐tin oxide/hole‐injection layer/Eu complex‐doped PVK/hole‐blocking layer/electron transport layer/electron‐injection layer/Al was employed. Red emission originating from Eu complex was observed. Relatively high luminance of 50 cd/m2 and an efficiency of 0.2% were obtained. Copyright © 2004 John Wiley & Sons, Ltd.
Asymmetric hydrogenation of ketones catalyzed by silica‐supported chitosan‐iron‐nickel complex
Authors: Zhou Da‐Qing , Zhou De‐Jun , Cui Xiao‐Hua , Wang Fu‐Ming , Huang Mei‐Yu , Jiang Ying‐Yan 
Published: May 2004

AbstractA new silica‐supported biopolymer‐metal complex, silica‐supported chitosan‐iron‐nickel complex was prepared by a very simple method. This complex catalyst can be used as a catalyst in the asymmetric hydrogenation of propiophenone to (R)‐(+)‐1‐phenyl‐1‐propanol and acetophenone to (R)‐(+)‐1‐phenyl ethanol in 91.7 and 77.7% optical yields, respectively, at 110°C and under 70 kg/cm2 pressure. The catalyst could be reused several times without any remarkable change in the catalytic activity. Copyright © 2004 John Wiley & Sons, Ltd.
Reactive melt blends of thermoplastic polyolefins, MAH‐g‐PP and nylon 6
Authors: Kim Min Soo , Kim Byung Kyu 
Published: May 2004

AbstractReactive melt blends of an ethylene‐propylene‐diene terpolymer (EPDM) based thermoplastic elastomer (TPE), maleic anhydride grafted polypropylene (MAH‐g‐PP), and nylon 6 were prepared in a single screw extruder and evaluated in terms of morphological, rheological, thermal, dynamic mechanical, and mechanical properties of the blends. It was found that MAH‐g‐PP‐co‐nylon 6 copolymers were in situ formed and acted as effective compatibilizers for polypropylene (PP) and nylon 6. Phase separation of PP and EPDM in TPE increased with the addition and increasing amount of MAH‐g‐PP and nylon 6, leading to decreased glass transition temperature (Tg) of TPE and increased crystalline melting temperature (Tm) of PP. Copyright © 2004 John Wiley & Sons, Ltd.
The basic research on physiological property of functionalized hyaluronan—I. Effect of hyaluronan and sulfated hyaluronan on cell proliferation of human epidermal keratinocytes
Authors: Satoh Takashi , Nagahata Misao , Teramoto Akira , Hatimori Akira , Abe Koji , Im Seung Soon 
Published: May 2004

AbstractHyaluronan (HA) is one of the polysaccharides that is found widely in connective tissue of mammals, and it has no sulfate group and high molecular weight in comparison with other glycosaminoglycans. Glycosaminoglycans are deeply concerned with the manifestation of biofunctions not only by their physical properties but also by physiological ones. In this study, sulfated HA (S‐HA) with various degrees of sulfate substitution and high molecular weight will be synthesized in order to give HA new biological functions. Moreover, the effect of HA and S‐HA on cell proliferation of human epidermal keratinocytes in vitro will be discussed. HA did not affect lag phase, but growth rate (metabolic turnover) of the cell in a logarithmic growth phase which was controlled by the molecular weight of HA. S‐HA stimulated the cell proliferation in the low concentration region under 1 μg/ml. While it inhibited the cell proliferation in the high concentration region over 10 μg/ml. It strongly suppressed the cell proliferation in the logarithmic growth metaphase. These facts were considered to be caused by the change of the cell‐matrix and/or cell–cell interactions. Copyright © 2004 John Wiley & Sons, Ltd.
Glucose oxidase electrodes of polyaniline, poly(o‐toluidine) and their copolymer as a biosensor: a comparative study
Authors: Borole D. D. , Kapadi U. R. , Mahulikar P. P. , Hundiwale D. G. 
Published: May 2004

AbstractA simple technique is described for constructing a glucose sensor by the entrapment of glucose oxidase (GOD) in a polyaniline (PA), poly(o‐toluidine) (POT) and their copolymer poly(aniline‐co‐o‐toluidine) (PA‐co‐POT) thin films, which were electrochemically deposited on a platinum plate in phosphate and acetate buffer. The maximum current response was observed for PA, POT, and PA‐co‐POT GOD electrodes at pH 5.5 and potential 0.60 V (v. Ag/AgCl). The phosphate buffer gives fast response as compared to acetate buffer in amperometric measurements. PA GOD electrode shows the fastest response followed by PA‐co‐POT and POT GOD electrodes. Copyright © 2004 John Wiley & Sons, Ltd.
Molecular design, synthesis, and nonlinear optical properties of novel T‐type polyimides with exceptionally high thermal stability of the second harmonic generation
Authors: Lee Ju‐Yeon , Bang Han‐Bae , Park Eun‐Ju , Rhee Bum Ku , Lee Seung Mook , Lee Jin Hyun 
Published: May 2004

Abstract2,5‐Bis‐(3,4‐dicarboxyphenylcarboxyethoxy)‐4′‐nitrostilbene dianhydride was prepared and reacted with 1,4‐phenylenediamine, 4,4′‐oxydianiline, 4,4′‐diaminobenzanilide, and 4,4′‐(hexafluoroisopropylidene)dianiline to yield unprecedented novel T‐type polyimides (4–7) containing 2,5‐dioxynitrostilbenyl groups as nonlinear optical chromophores, which constituted parts of the polymer backbones. 4–7 were soluble in polar solvents such as acetone and N,N‐dimethylformamide. They showed thermal stability up to 300 °C in thermogravimetric analysis thermograms; the glass‐transition temperatures obtained from differential scanning calorimetry thermograms were around 153 °C. The second harmonic generation (SHG) coefficients (d33) of poled polymer films at the 1064‐cm−1 fundamental wavelength were around 4.35 × 10−9 esu. The dipole alignment exhibited exceptionally high thermal stability even at 45 °C higher than the glass‐transition temperature, and there was no SHG decay below 200 °C because of the partial main‐chain character of the polymer structure, which was acceptable for nonlinear optical device applications. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3189–3199, 2004
A first‐principles study on the magnetism of an Fe chain along the [110] direction on Cu(001)
Authors: Jin Ying Jiu , Kim In Gee , Lee Jae Il 
Published: May 2004

AbstractMagnetic nanowires currently attract much attention due to possible applications in high‐density memory storage. The cover picture, taken from the Editor's Choice paper [1] of this issue, is the spin density contour plot for a Fe chain along the [110] direction on Cu(001) and shows a large eruption of the majority spins from the Fe atom site toward the vacuum region. The supported Fe chain exhibits a large enhanced magnetic moment of the Fe atom compared with that of bulk Fe.The corresponding author, Jae Il Lee, is Professor at the Inha University, Incheon. His research group at the Department of Physics works on theoretical investigations of electronic structure and magnetism of materials using first‐principles energy band calculations.This paper is a contribution from the International Symposium on Magnetic Materials and Applications and Winter Conference of the Korean Magnetics Society (2003 SOMMA/KMS Meeting), Daejeon, Korea, 3–6 December 2003. The proceedings of this conference are published in two parts in the present issue of phys. stat. sol. (b) and in phys. stat. sol. (a) 201, No. 8 (2004).
A generalized semantics of PROMELA for abstract model checking
Authors: Gallardo María del Mar , Merino Pedro , Pimentel Ernesto 
Published: May 2004

Abstract.

Semantics of description languages for complex systems are a central issue for implementing verification methods such as
abstract model checking
. This technique is employed to verify systems by inspecting only a small state space that represents its potential behaviors. This paper presents a generalized operational semantics of the modelling language promela that provides the theoretical basis to introduce this promising method in the model checker SPIN. The generalization consists of identifying language aspects affected by the abstraction. Using these aspects as parameters, it is possible to obtain and relate different interpretations of the language. The new semantics provides a framework to reason about how to construct the tool αspin as an extension of spin.
Effects of alternative prey on predation by small mammals on gypsy moth pupae
Authors: Elkinton Joseph S. , Liebhold Andrew M. , Muzika Rose‐Marie 
Published: May 2004

AbstractPrevious work shows that predation by small mammals is a dominant cause of mortality of low‐density gypsy moths in North America and that declines in small mammal density result in increases in gypsy moth density. Here we examined whether predation by small mammals is density dependent by way of a type III functional response, and how predation is influenced by alternative prey. First we showed that the preference of predators for gypsy moth pupae was low compared to other experimental prey items, such as mealworm pupae and sunflower seeds. Predation on gypsy moth pupae was characterized by a type II functional response with percent predation highest at the lowest prey densities, whereas the functional response to sunflower seeds was characterized by a type III functional response in which predation increased with increasing prey density. These results suggest that predation by small mammals is unlikely to stabilize low‐density gypsy moth populations.
Peer Review: An Essential Step in the Publishing Process
Authors: Weil Jon 
Published: May 2004

AbstractAmong the many steps involved in publishing a professional paper, peer review of the submitted manuscript presents both a challenge and an opportunity. Peer review is essential to ensuring that published papers meet appropriate research, scholarship and journal criteria. Peer review is also a valuable resource, providing detailed, professional evaluations that help authors carry out and present scholarship of the highest quality. When combined with the commitment of the Journal of Genetic Counseling to encourage and mentor authors, it is also a resource for developing writing skills.
Infection Control Measures for Operative Procedures in Severe Acute Respiratory Syndrome–related Patients
Authors: Chee Victor Wei Ter , Khoo Mark Li-Chung , Lee Sow Fong , Lai Yeow Choy , Chin Ngek Mien 
Published: May 2004

Background
Singapore reported its first case of Severe Acute Respiratory Syndrome (SARS) in early March 2003 and was placed on the World Health Organization's list of SARS-affected countries on March 15, 2003. During the outbreak, Tan Tock Seng Hospital was designated as the national SARS hospital in Singapore to manage all known SARS patients. Stringent infection control measures were introduced to protect healthcare workers and control intrahospital transmission of SARS. Work-flow processes for surgery were extensively modified.

Methods
The authors describe the development of infection control measures, the conduct of surgical procedures, and the management of high-risk procedures during the SARS outbreak.

Results
Forty-one operative procedures, including 15 high-risk procedures (surgical tracheostomy), were performed on SARS-related patients. One hundred twenty-four healthcare workers had direct contact with SARS patients during these procedures. There was no transmission of SARS within the operating room complex.

Conclusions
Staff personal protection, patient risk categorization, and reorganization of operating room workflow processes formed the key elements for the containment of SARS transmission. Lessons learned during this outbreak will help in the planning and execution of infection control measures, should another outbreak occur.
Remifentanil Directly Activates Human N-methyl-d-aspartate Receptors Expressed in Xenopus laevis Oocytes
Authors: Hahnenkamp Klaus , Nollet Joke , Van Aken Hugo K. , Buerkle Hartmut , Halene Tobias , Schauerte Svenja , Hahnenkamp Anke , Hollmann Markus W. , Strümper Danja , Durieux Marcel E. , Hoenemann Christian W. 
Published: May 2004

Background
Clinical studies suggest that intraoperative administration of the clinical remifentanil formulation Ultiva (GlaxoWellcome GmbH & Co, Bad Oldesloe, Germany) increases postoperative pain and postoperative analgesic requirements, but mechanisms remain unclear. N-methyl-D-aspartate (NMDA) receptors are thought to play a major role in development of postoperative pain and opiate tolerance. The authors hypothesized that Ultiva directly stimulates human NMDA receptors.

Methods
To test this hypothesis, the authors expressed human NR1A/NR2A and NR1A/NR2B NMDA receptors in Xenopus laevis oocytes by injection of messenger RNA prepared in vitro. After protein expression, they used a two-electrode voltage clamp to measure currents induced by NMDA receptor agonists and opioids.

Results
Noninjected cells were unresponsive to all compounds tested. Glutamate/glycine (1 nM-1 mM each) or Ultiva (0.01 pM-0.1 mM) stimulated NMDA receptors concentration dependently. NR1A/2A EC50 values were 8.0 microM/12 microM for glutamate/glycine and 3.5 nM for Ultiva, and NR1A/2B EC50 values were 3.9 microM/1.9 microM for glutamate/glycine and 0.82 microM for Ultiva. Glycine in combination with Ultiva showed no additive effect compared with Ultiva alone. Ultiva-induced currents were inhibited by MK-801 (pore blocker) but not by 7-CK (glycine antagonist), D-AP5 (glutamate antagonist), or naloxone. Fentanyl (10 microM) did not stimulate NMDA receptors.

Conclusion
These data indicate that Ultiva but not fentanyl stimulates NMDA receptors of different subunit combinations (NR1A/2A, NR1A/2B). The mechanism seems to be allosteric activation of the NMDA receptor.
Differentiating among Hospitals Performing Physiologically Complex Operative Procedures in the Elderly
Authors: Wachtel Ruth E. , Dexter Franklin 
Published: May 2004

Background
The authors previously showed how a statewide discharge abstract database could be used to quantify for stakeholders how surgical practices differ among hospitals. The two pediatric hospitals in Iowa differ from other hospitals in Iowa based on their providing a more diverse, comprehensive, and physiologically complex selection of procedures in younger patients. Physiologically complex surgery performed in children aged 0-2 yr has been regionalized to a few high-volume facilities.

Methods
The same inpatient discharge abstract database was used to quantify physiologically complex operative procedures performed throughout Iowa in patients aged 80 yr and older during January through June 2001.

Results
In contrast to earlier results with pediatric patients using the same database, hospitals performing physiologically complex procedures in the elderly could not readily be differentiated from one another based on the numbers and types of procedures performed (P < 0.001 when comparing geriatrics vs. pediatrics in terms of the distributions of numbers of procedures, the distributions of numbers of different types of procedures, or the distributions of numbers of rare procedures performed at different hospitals). Additional analyses showed that one hospital did perform relatively more rare procedures in geriatric patients and had a relatively larger percentage of patients who traveled beyond their local county to reach it.

Conclusions
Results observed for geriatric patients provide further evidence of the validity of these methods and the usefulness of discharge abstract data for comparing surgical practices among facilities. A hospital can use discharge abstract data to assist governmental agencies, charitable organizations, philanthropists, insurers, etc., in appreciating the unique contributions of individual hospitals to surgical care.