bluuebunny/crossref_metadata_2025 huggingface dataset:
Alpha‐1 adrenoceptors: evaluation of receptor subtype‐binding kinetics in intact arterial tissues and comparison with membrane binding
Authors: Tanaka Takashi , Zhang Li , Suzuki Fumiko , Muramatsu Ikunobu
Published: February 2004

The binding kinetics of [3H]‐prazosin were measured using intact segments of rat tail artery (RTA) and thoracic aorta (RAO), and the data were compared with those obtained using a conventional membrane ligand‐binding method.

In intact RTA and RAO segments, [3H]‐prazosin bound reversibly in a time‐dependent and receptor‐specific manner at 4°C to alpha‐1 adrenoceptors (ARs) of the plasma membrane, with affinities (pKD: 9.5 in RTA; 9.9 in RAO) that were in agreement with values estimated by a conventional membrane ligand‐binding method. However, nonspecific binding was considerably higher in RAO than RTA, failing to detect clearly the specific binding at high concentrations (>300 pM) of [3H]‐prazosin in binding experiments with RAO segments and membranes.

The abundance of receptor in the RTA and RAO (Bmax mg−1 of total tissue protein), estimated using the tissue segment‐binding approach (527±14 fmol mg−1 for RTA; 138±4 fmol mg−1 for RAO), was about 25‐fold higher than values estimated using a conventional membrane‐binding method (22±5 fmol mg−1 for RTA; 5±1 fmol mg−1 for RAO).

Binding competition experiments using intact tissue segments or membranes derived from RTA tissue yielded comparable data, indicating a coexistence of alpha‐1A AR (high affinity for prazosin, KMD‐3213 and WB4101 and low affinity for BMY 7378) and alpha‐1B AR (high affinity for prazosin but low affinity for KMD‐3213, WB4101 and BMY 7378).

In RAO tissue, careful evaluation of the tissue segment‐binding assay revealed the coexpression of alpha‐1B AR (high affinity for prazosin, but low affinity for KMD‐3213 and BMY 7378) and alpha‐1D AR (high affinity for prazosin and BMY 7378, but low affinity for KMD‐3213), whereas the membrane‐binding approach failed to detect these receptor subtypes with certainty.

The present study indicates that previous estimates of alpha‐1 AR density and alpha‐1 AR subtypes obtained by a conventional membrane‐binding approach, as opposed to our improved tissue segment‐binding assay, may have substantially underestimated the abundance of receptors present in arterial tissues, and may have failed to identify accurately the presence of receptor subtypes. Advantages and disadvantages of the tissue segment‐binding approach are discussed.

British Journal of Pharmacology (2004) 141, 468–476. doi:10.1038/sj.bjp.0705627
5‐Hydroxytryptamine is biotransformed by CYP2C9, 2C19 and 2B6 to hydroxylamine, which is converted into nitric oxide
Authors: Fradette Caroline , Yamaguchi Nobuharu , Du Souich Patrick
Published: February 2004

There is circumstantial evidence suggesting that 5‐hydroxytryptamine (5‐HT) could be biotransformed by enzymatic systems other than monoamino oxidase A, and that the isoforms of cytochrome P450 may be a source of nitric oxide. This study aimed to assess whether cytochrome P450 contributes to 5‐HT biotransformation, and to provide evidence that 5‐HT metabolism generates nitric oxide.

Addition of 5‐HT to cultured hepatocytes yielded 5‐hydroxyindol acetic acid, a formation modulated by cytochrome P450 enzyme inducers and inhibitors. Recombinant human CYP2B6, 2C9 and 2C19 biotransformed 5‐HT in 5‐hydroxyindol acetic acid, but not CYP1A2, 2D6 or 3A4.

Cultured hepatocytes with 5‐HT generated nitric oxide, the amount of which was altered by cytochrome P450 enzyme inducers and inhibitors. In the presence of CYP2B6, 2C9 and 2C19, 5‐HT relaxed precontracted isolated aortic rings, with or without endothelium, an effect prevented by the addition of methylene blue and an inhibitor of catalase, but not by myoglobin. In the absence of catalase, hydroxylamine was always assayed as a byproduct of 5‐HT metabolism.

In conclusion, CYP2B6, 2C9 and 2C19 biotransform 5‐HT, yielding hydroxylamine, which is converted to nitric oxide in the presence of catalase.

British Journal of Pharmacology (2004) 141, 407–414. doi:10.1038/sj.bjp.0705632
Octreotide regulates CC but not CXC LPS‐induced chemokine secretion in rat Kupffer cells
Authors: Valatas Vassilis , Kolios George , Manousou Pinelopi , Notas George , Xidakis Costas , Diamantis Ioannis , Kouroumalis Elias
Published: February 2004

Kupffer cells (KC) and lipopolysaccharide (LPS) interaction is the initial event leading to hepatic inflammation and fibrosis in many types of liver injury. We studied chemokine secretion by KC activated with LPS and the possible effect of the somatostatin analogue octreotide, in the regulation of this process.

KC isolated from Sprague–Dawley rats were cultured in the presence of LPS added alone or with different concentrations of octreotide for 24 and 48 h, and chemokine production was assessed in culture supernatants by ELISA. CC chemokine mRNA expression was assessed by semiquantitative RT–PCR.

Vehicle‐stimulated KC produced a basal amount of CC and CXC chemokines. LPS‐stimulated KC secreted significantly increased amounts of IL‐8 (GRO/CINC‐1) (P<0.001), MIP‐2 (P<0.001), MCP‐1 (P<0.001), and RANTES (P<0.01).

Octreotide inhibited LPS‐induced secretion of the CC chemokines MCP‐1 (P<0.05) and RANTES (P<0.05), but not the CXC chemokines IL‐8 (GRO/CINC‐1) and MIP‐2, in a concentration‐dependent manner. Downregulation of basal and LPS‐induced mRNA expression of the CC chemokines was also observed in the presence of octreotide.

Pretreatment with phosphatidylinositol 3 (PI3)‐kinase inhibitors reduced chemokine production by LPS‐treated KC in both the mRNA and protein level. Furthermore, it prevented the octreotide inhibitory effect on LPS‐induced chemokine secretion, indicating a possible involvement of the PI3‐kinase pathway.

In conclusion, these data demonstrate that chemokine secretion by KC can be differentially regulated by octreotide, and suggest that this somatostatin analogue may have immunoregulatory effects on resident liver macrophages.

British Journal of Pharmacology (2004) 141, 477–487. doi:10.1038/sj.bjp.0705633
Differential effects of P2Y1 and P2Y12 nucleotide receptors on ERK1/ERK2 and phosphatidylinositol 3‐kinase signalling and cell proliferation in serum‐deprived and nonstarved glioma C6 cells
Authors: Czajkowski Rafał , Banachewicz Wiktor , Ilnytska Olga , Drobot Ludmila B , Barańska Jolanta
Published: February 2004

We have previously shown that, in glioma C6 cells, two nucleotide ADP‐sensitive receptors coexist: P2Y1, coupled to PLC and responsible for Ca2+ release, and P2Y12, negatively coupled to adenylate cyclase. In the present study, we examined the effects of the stimulation of these two receptors on ERK1/2 and PI3‐K activation, and cell proliferation in either serum‐deprived or nonstarved C6 cells.

In response to ADP and its analogues, in serum‐starved cells, both p44 ERK1 and p42 ERK2 were activated in a time‐dependent manner, as monitored by Western blot analysis using an antiphospho‐p42/p44 MAPK antibody. The phosphorylation was reduced both by removal of the extracellular Ca2+ and partially or almost completely by MRS2179 or AR‐C69931MX, specific antagonists of the P2Y1 and P2Y12 receptors, respectively. The inhibitory effect of antagonists was additive. These data indicate the involvement of both receptors, P2Y1 and P2Y12, in the ERK1/2 activation, but the P2Y12 receptor contribution predominates.

ERK1/2 activity was positively correlated with cell proliferation of cultured glioma C6 cells.

In nonstarved cells, ADP markedly decreased the PI3‐K activity. In contrast, in serum‐starved cells, ADP evoked an increase in the PI3‐K activity. Blocking of the P2Y1 receptor by MRS2179 additionally increased this ADP response. These results suggest that the P2Y1 receptor has an inhibitory and the P2Y12 receptor a stimulatory effect on PI3‐K signalling pathway.

RT–PCR analysis revealed different mRNA expression of both receptors in starved and nonstarved cells. In nonstarved cells, the P2Y1 receptor mRNA predominates, whereas in serum‐deprived cells the expression of P2Y12 mRNA becomes more pronounced.

British Journal of Pharmacology (2004) 141, 497–507. doi:10.1038/sj.bjp.0705639
The contractile action of leukotriene B4 in the guinea‐pig lung involves a vascular component
Authors: Sakata Kiyoto , Dahlén Sven‐Erik , Bäck Magnus
Published: February 2004

Leukotriene B4 (LTB4) is a potent leukocyte chemoattractant, acting on specific receptors, BLT receptors. The aim of this study was to examine the mechanism of action of LTB4 in the guinea‐pig lung, using strips of lung parenchyma (GPLP), spirals of trachea (GPT) and bronchus (GPB) and rings of pulmonary artery (GPPA). Mechanical responses were studied in organ baths, and mediator release was assessed using enzyme immuno assay.

LTB4 induced similar contractions of GPLP and GPPA, whereas LTB4 had only small contractile effects in GPT and GPB. In addition, the contractile response to LTB4 was reproduced in the human pulmonary artery.

In the GPLP, the unselective BLT receptor antagonist ONO‐4057 abolished the contractions induced by LTB4, whereas the selective BLT1 receptor antagonist U–75302 only partly inhibited the LTB4‐induced contractions. In the GPPA, both antagonists abolished the response to LTB4.

The effect of LTB4 in GPPA and GPLP was indirect and mediated by the release of thromboxane A2 and histamine, as supported by selective pharmacologic interventions and measurements of thromboxane B2 and histamine in the organ baths.

In conclusion, the results indicate a new biological function of LTB4, namely to constrict isolated pulmonary arteries. Moreover, the findings suggest that the LTB4‐induced contractions of GPPA were mediated by a BLT1 receptor, whereas BLT2 receptor activation accounted for a major part of the contraction of GPLP, making the latter preparation a suitable assay for BLT2 receptors.

British Journal of Pharmacology (2004) 141, 449–456. doi:10.1038/sj.bjp.0705641
Structure–activity analysis of a novel NR2C/NR2D‐preferring NMDA receptor antagonist: 1‐(phenanthrene‐2‐carbonyl) piperazine‐2,3‐dicarboxylic acid
Authors: Feng Bihua , Tse Heong W , Skifter Donald A , Morley Richard , Jane David E , Monaghan Daniel T
Published: February 2004

(2S*,3R*)‐1‐(biphenyl‐4‐carbonyl)piperazine‐2,3‐dicarboxylic acid (PBPD) is a moderate affinity, competitive N‐methyl‐D‐aspartate (NMDA) receptor antagonist with an atypical pattern of selectivity among NMDA receptor 2 subunit (NR2) subunits. We now describe the activity of several derivatives of PBPD tested at both rat brain NMDA receptors using L‐[3H]‐glutamate binding assays and at recombinant receptors expressed in Xenopus oocytes.

Substituting various branched ring structures for the biphenyl group of PBPD reduced NMDA receptor activity. However, substituting linearly arranged ring structures – fluorenone or phenanthrene groups – retained or enhanced activity.

Relative to PBPD, the phenanthrene derivative (2S*,3R*)‐1‐(phenanthrene‐2‐carbonyl)piperazine‐2,3‐dicarboxylic acid (PPDA) displayed a 30‐ to 78‐fold increase in affinity for native NMDA receptors. At recombinant receptors, PPDA displayed a 16‐fold (NR2B) to 94‐fold (NR2C) increase in affinity over PBPD.

Replacement of the biphenyl group of PBPD with a 9‐oxofluorene ring system resulted in small changes in receptor affinity and subtype selectivity.

2′‐Bromo substitution on the biphenyl group of PBPD reduced antagonist affinity 3‐ to 5‐fold at NR2A‐, NR2B‐ and NR2D‐containing receptors, but had little effect on NR2C‐containing receptors. In contrast, 4′‐fluoro substitution of the biphenyl ring of PBPD selectively increased NR2A affinity.

The aromatic rings of PBPD and PPDA increase antagonist affinity and appear to interact with a region of the NMDA receptor displaying subunit heterogeneity. PPDA is the most potent and selective NR2C/NR2D‐preferring antagonist yet reported and thus may be useful in defining NR2C/NR2D function and developing related antagonists with improved NMDA receptor subtype selectivity.

British Journal of Pharmacology (2004) 141, 508–516. doi:10.1038/sj.bjp.0705644
Influence of codeposition on the performance of CuPc–C60 heterojunction photovoltaic devices
Authors: Sullivan P. , Heutz S. , Schultes S. M. , Jones T. S.
Published: February 2004

We investigate the effects of introducing codeposited mixed layers on the performance of copper phthalocyanine (CuPc)–fullerene (C60) heterojunction photovoltaic devices. Significant improvements in device performance are seen when mixed layers are used compared to discrete layers. The effects of composition are examined for a series of devices incorporating mixed layers with well-defined composition ratios. Atomic force microscopy and electronic absorption spectroscopy studies show that the mixed layer films are smooth and amorphous, and undergo intermolecular intermixing. Finally, the use of multiple mixed layers leads to additional enhancements due to the creation of a gradient of donor–acceptor compositions that results in improved channels for charge transport.
Molecular dynamics simulations of Ar+-induced transport of fluorine through fluorocarbon films
Authors: Humbird David , Graves David B. , Hua Xuefeng , Oehrlein Gottlieb S.
Published: February 2004

Recent experimental studies of fluorocarbon (FC) plasmas etching various substrates suggest that ions will transport initially bound fluorine (F) through overlying FC films, thereby defluorinating these films and inducing fluorination reaction with the underlying substrate material. Simulations of thermal CF2 on Si with simultaneous bombardment by energetic Ar+ demonstrate this defluorination phenomenon, showing that F is separated from adsorbed CF2 and mixed into the underlying Si, initiating etching. Additionally, this creates dangling bonds on the surface where CF2 may adsorb. Thus, our simulations show that F and C uptake is enhanced by energetic rare gas ion impact, the number of Si–F bonds is greatly increased, and the resultant Si etch rate is higher than expected from physical sputtering alone. The results are compared to experimental measurements made under similar conditions, and the mechanisms of ion-induced F transport are identified.
Ultrafast polarization switching in thin-film ferroelectrics
Authors: Li J. , Nagaraj B. , Liang H. , Cao W. , Lee Chi. H. , Ramesh R.
Published: February 2004

We present an experimental approach to study the ultrafast polarization switching dynamics in thin-film ferroelectrics. A semiconductor photoconductive switch with femtosecond laser illumination is used as a “pulse generator” to produce jitter-free, sub-100 ps rise time step-function-like electrical pulses. Quantitative measurements yield a polarization switching time, ts, of ∼220 ps when measured with a 5 V, 68 ps rise time input electrical pulse. Modeling of the switching transients using the Merz–Ishibashi model and Merz–Shur model of switching kinetics yields a quantitative estimate of the characteristic switching time constant, t0, of ∼70–90 ps.
Intrinsic thermal robustness of tunneling spin polarization in Al/Al2O3/Co junctions
Authors: Kant C. H. , Kohlhepp J. T. , Swagten H. J. M. , de Jonge W. J. M.
Published: February 2004

Through a direct observation, based on the spin-polarized tunneling technique, we explore the thermal stability of tunneling spin polarization in Al/Al2O3/Co junctions. Thermal robustness of this parameter, which is of key importance for magnetic tunnel junction performance, is established for in situ postdeposition anneal temperatures up to 500 °C. This stability is consistent with detailed in situ x-ray photoelectron spectroscopy measurements on the Al2O3/Co system which show no structural changes during the anneal. Our results imply that, for comparable magnetic tunnel junction devices, thermal stability is not limited by intrinsic processes in the Al2O3 barrier and its interfaces. With ex situ postdeposition annealing in an Ar-atmosphere, which leads to severe degradation of the spin polarization above 250 °C, we demonstrate that the spin polarization is extremely vulnerable to diffusion of impurities.
Understanding the submicron domain structure of MnAs thin films on GaAs(001): Magnetic force microscopy measurements and simulations
Authors: Engel-Herbert R. , Mohanty J. , Ney A. , Hesjedal T. , Däweritz L. , Ploog K. H.
Published: February 2004

Over a wide temperature range of 30 °C around room temperature, MnAs films on GaAs(001) semiconductor substrates break up into ordered arrays of submicron-sized ferromagnetic α and paramagnetic β wires. Both the hard and the easy axis of magnetization (perpendicular to the wires) lie in the film plane and a large variety of complex domain patterns are found in micromagnetic investigations with magnetic force microscopy (MFM). A systematic analysis of the domain configurations is given and the most likely configurations are identified through MFM contrast simulations.
Color-tunable multilayer light-emitting diodes based on conjugated polymers
Authors: Huang C. C. , Meng H. F. , Ho G. K. , Chen C. H. , Hsu C. S. , Huang J. H. , Horng S. F. , Chen B. X. , Chen L. C.
Published: February 2004

Wide-range low-voltage continuous color tuning is achieved in multilayer light-emitting diodes based exclusively on the commonly used high-efficiency electroluminescent conjugated polymers. There are three layers for red, green, and blue emission, and one extra layer for electron blocking. The color of the emitted photon depends on the position of the electron-hole recombination. Due to the stronger field dependence of the electron mobility relative to the hole mobility, the recombination zone is pushed away from the cathode and concentrated in different emissive layers as the voltage increases.
Moment determination of magnetic force microscope tips by imaging superparamagnetic films
Authors: Vergara J. , Eames P. , Merton C. , Madurga V. , Dahlberg E. D.
Published: February 2004

A method to characterize the magnetic moment of a magnetic force microscopy (MFM) tip is presented. The response of the MFM while imaging a superparamagnetic film is compared to a nonmagnetic reference. A simple model is used to compare the experimental results with a calculation of the response of the MFM tip due to the interactions with the magnetization of a superparamagnetic film.
Electroreflectance study on the polarization field in InGaN/AlInGaN multiple quantum wells
Authors: Hsu T. M. , Lai C. Y. , Chang W.-H. , Pan C.-C. , Chuo C.-C. , Chyi J.-I.
Published: February 2004

We present an electroreflectance investigation on the polarization field in InGaN/AlInGaN quantum wells (QWs) grown on GaN, in which the AlInGaN barrier is lattice-matched to the GaN substrate. Due to the quantum-confined Stark effect on the QWs, the bias-dependent spectra reveal a paraboliclike energy shift, an intensity minimum, and an 180° phase change at the flat-band voltage. By using this technique, the polarization field can be measured precisely. We found that the polarization field in the InGaN/AlInGaN QW is reduced significantly as compared with that in the InGaN/GaN system. The reduced polarization field is attributed to the contribution of spontaneous polarization in the quaternary barrier, which tends to compensate the piezoelectric polarization in the InGaN QWs.
Influence of substrate–film interface engineering on the superconducting properties of YBa2Cu3O7−δ
Authors: Rijnders Guus , Currás Seve , Huijben Mark , Blank Dave H. A. , Rogalla Horst
Published: February 2004

The atomic stacking sequence at the substrate–film interface plays an essential role in the heteroepitaxial growth of REBa2Cu3O7−δ. During initial growth, the interface configuration influences the surface morphology and structural properties of the film, due to the formation of anti-phase boundaries (APBs) by coalescence of islands with different stacking sequences. In this study, the interface configuration is accurately controlled by both the terminating atomic layer of the SrTiO3 substrate and the stoichiometry of the first unit cell layer. Using this capability the network of APBs and, therefore, the in-plane ordering is tuned, allowing the study of its influence on the structural and electrical properties of the YBa2Cu3O7−δ film. The critical temperature Tc is depressed by increase of the in-plane ordering, which strongly indicates that the presence of APBs in the sample favors the oxygen in-diffusion.
High-throughput scanning confocal microscope for single molecule analysis
Authors: Sabanayagam Chandran R. , Eid John S. , Meller Amit
Published: February 2004

An automated and programmable confocal microscope that can acquire upwards of 103 single-molecule fluorescence resonance energy transfer (FRET) time traces is presented. The microscope augments the capabilities of current instruments by employing a flow cell that allows full control of the sample’s chemical environment, automatic locating and probing of single molecules, and an automatic focusing feature that enables the unattended scanning of large areas of the sample. This microscope performs routine acquisition of thousands of single-molecule events, in a highly reproducible fashion. These capabilities were utilized in recording the distributions of FRET efficiencies arising from control DNA molecules specifically labeled with internal donor-acceptor reporters.
Effect of anode dielectric coating on Hall thruster operation
Authors: Dorf L. , Raitses Y. , Fisch N. J. , Semenov V.
Published: February 2004

An interesting phenomenon observed in the near-anode region of a Hall thruster is that the anode fall changes from positive to negative upon removal of the dielectric coating, which is produced on the anode surface during the normal course of Hall thruster operation. The effect of the anode coating on the anode fall is studied experimentally using both biased and emissive probes. Measurements of discharge current oscillations indicate that thruster operation is more stable with the coated anode. The physical mechanism of this phenomenon is not yet understood.
Transverse modes of photonic crystal vertical-cavity lasers
Authors: Danner Aaron J. , Raftery James J. , Yokouchi Noriyuki , Choquette Kent D.
Published: February 2004

The control of lateral mode operation using a photonic crystal in a vertical-cavity surface-emitting laser (VCSEL) is analyzed and confirmed experimentally. By controlling design parameters of the photonic crystal pattern, we have produced photonic crystal VCSELs that operate in higher order defect modes in addition to the fundamental defect mode. The transverse modal behavior is consistent with the predictions of a theoretical model in which the etching depth dependence of the air holes of the photonic crystals is considered. We also have determined the lower limit of optical confinement required from the photonic crystal pattern to influence the output beam of the laser.
Fabrication of well-aligned carbon nanofiber array and its gaseous-phase adsorption behavior
Authors: Hsieh Chien-Te , Chen Jin-Ming , Kuo Rong-Rong , Huang Yue-Hao
Published: February 2004

Well-aligned and highly porous carbon nanofiber (CNF) arrays were obtained by a template synthesis method, using epoxy-based solution as carbon precursor in the present study. The diameter and length of the nanofiber were accord with pore size of 100 nm and thickness of 50 μm of the anodic aluminum oxide membrane, respectively. Scanning electron microscope and transmission electron microscopy showed that the open-tipped CNFs had well-defined one-dimensional (1D) structures and high porosity. N2 adsorption experiment indicated that the mesoporous CNF array exhibited a high Brunauer–Emmett–Teller surface area of 780 m2/g. Compared with commercial active carbon, the CNF array has a higher monolayer adsorption capacity of n-hexane due to its unique pore structure. Adsorption kinetics showed that the CNFs can rapidly achieve an equilibrium coverage, indicating smaller diffusion resistance during adsorption. These results are beneficial for the hollow CNF array as a real-time gas sensing material in the future.
Response speed of SnO2-based H2S gas sensors with CuO nanoparticles
Authors: Chowdhuri Arijit , Gupta Vinay , Sreenivas K. , Kumar Rajeev , Mozumdar Subho , Patanjali P. K.
Published: February 2004

CuO nanoparticles on sputtered SnO2 thin-film surface exhibit a fast response speed (14 s) and recovery time (61 s) for trace level (20 ppm) H2S gas detection. The sensitivity of the sensor (S∼2.06×103) is noted to be high at a low operating temperature of 130 °C. CuO nanoparticles on SnO2 allow effective removal of excess adsorbed oxygen from the uncovered SnO2 surface due to spillover of hydrogen dissociated from the H2S–CuO interaction.
Measurement of the photorefractive space-charge field in a ferroelectric mesogen
Authors: Talarico M. , Termine R. , Barberio G. , Pucci D. , Ghedini M. , Golemme A.
Published: February 2004

We report on the measurement of the photorefractive space-charge field in a chiral smectic C mesophase. The liquid crystal is intrinsically photoconducting and undoped. The space-charge field amplitude, obtained from a model connecting the induced refractive index modulation with the electric fields within the medium, is only 1% of the applied field. Nonetheless, high refractive index modulations Δn∼10−3 can be obtained because of the high spontaneous birefringence of the mesophase. The use of the standard models for inorganic crystalline photorefractive materials would have given a space-charge field amplitude two orders of magnitude higher.
High-power 280 nm AlGaN light-emitting diodes based on an asymmetric single-quantum well
Authors: Mayes K. , Yasan A. , McClintock R. , Shiell D. , Darvish S. R. , Kung P. , Razeghi M.
Published: February 2004

We demonstrate high-power AlGaN-based ultraviolet light-emitting diodes grown on sapphire with an emission wavelength of 280 nm using an asymmetric single-quantum-well active layer configuration on top of a high-quality AlGaN/AlN template layer. An output power of 1.8 mW at a pulsed current of 400 mA was achieved for a single 300 μm×300 μm diode. This device reached a high peak external quantum efficiency of 0.24% at 40 mA. An array of four diodes produced 6.5 mW at 880 mA of pulsed current.
High-strength Cu-based crystal-glassy composite with enhanced ductility
Authors: Louzguine Dmitri V. , Kato Hidemi , Inoue Akihisa
Published: February 2004

Low ductility of glassy alloys prevents their technical application as structural materials. In this work, we study the Cu-based crystal-glassy composite material with good mechanical properties. Formation of the Cu10Zr7 phase in the glassy matrix of a high-strength Cu50Zr30Ti10Nb10 bulk alloy upon solidification led to higher Young’s modulus and enhanced ductility of such a composite compared to Cu-based glassy alloys. The as-cast structure was studied by x-ray diffraction and scanning electron microscopy.
Active organic–inorganic sol gel with high thermal stability for nonlinear optical applications
Authors: Zhang Hongxi , Lu Dong , Fallahi Mahmoud
Published: February 2004

Second-harmonic generation and thermal stability of hybrid photosensitive sol-gel films doped with a side-chain electro-optic chromophore have been studied. Nonlinear optic coefficient d33 has been derived for the cross-linked and noncross-linked sol-gel films. The d33 of the cross-linked hybrid sol-gel film shows high stability at elevated temperature. No evident degradation in d33 was observed at 110 °C and only 20% of d33 decayed in 15 min at 180 °C. The results indicate that the film can meet the long-term stability requirement for optical components.
Thermal effects in quasi-continuous-wave Nd3+:Y3Al5O12 nanocrystalline-powder random laser
Authors: Feng Yan , Bisson Jean-Francois , Lu Jianren , Huang Shenghong , Takaichi Kazunori , Shirakawa Akira , Musha Mitsuru , Ueda Ken-ichi
Published: February 2004

We report an experimental investigation on the thermal effects in a Nd3+:Y3Al5O12 nanocrystalline-powder random laser with a one-mirror structure by quasi-continuous-wave laser diode pumping. Extremely low thermal conductivity in powder and significant temperature dependence of the narrow emission spectrum of Nd3+:Y3Al5O12 leads to a laser line redshift and gain reduction with a higher heat deposit. Mode drifting induced by the temperature dependence of the refractive index is also discussed.
La
0.95
Sr
0.05
CoO
3
:
An efficient room-temperature thermoelectric oxide
Authors: Androulakis J. , Migiakis Pantelis , Giapintzakis J.
Published: February 2004

We present measurements of electrical resistivity, thermal conductivity, and thermopower of polycrystalline Sr-doped LaCoO3 with composition La0.95Sr0.05CoO3. Our data show that the investigated compound exhibits a very respectable room-temperature thermoelectric figure of merit value of 0.18. Our results not only show that oxides are promising candidates for thermoelectric cooling applications, but also point toward the need for careful theoretical calculations that will serve as a guide in producing the next generation of thermoelectric materials.
Scanning electrometer using the capacitive coupling in quantum Hall effect devices
Authors: Kawano Y. , Okamoto T.
Published: February 2004

We have constructed a scanning electrometer employing a quantum Hall effect (QHE) device. This technique uses capacitive coupling between sensor and sample to read out a change of longitudinal resistance of the sensor. This sensing mechanism was confirmed by measuring the magnetic field dependence of the readout signal and by an analysis based on a model of parallel-plate capacitor. Spatial mapping of Hall voltage profiles in the QHE state was demonstrated with this system.
Interfacial characteristics of HfO2 films grown on strained Si0.7Ge0.3 by atomic-layer deposition
Authors: Cho M.-H. , Chang H. S. , Moon D. W. , Kang S. K. , Min B. K. , Ko D.-H. , Kim H. S. , McIntyre Paul C. , Lee J. H. , Ku J. H. , Lee N. I.
Published: February 2004

The interfacial characteristics of gate stack structure of HfO2 dielectrics on strained Si0.7Ge0.3 deposited by atomic-layer deposition were investigated. An interfacial layer including GeOx layers was grown on a SiGe substrate, and the thickness of the GeOx layer at the interfacial layer was decreased after the annealing treatment, while SiO2 layer was increased. The ∼50-Å-thick HfO2 film with an amorphous structure was converted into a polycrystalline structure after rapid annealing at temperature of over 700 °C for 5 min. The interfacial silicate layer was effectively suppressed by GeOx formation, while the silicate layer was formed after the annealing treatment. GeOx formation in an as-grown film resulted in a decrease in the accumulation capacitance and an increase in the oxide trap charge.
Combined nanogap nanoparticles nanosensor for electrical detection of biomolecular interactions between polypeptides
Authors: Haguet V. , Martin D. , Marcon L. , Heim T. , Stiévenard D. , Olivier C. , El-Mahdi O. , Melnyk O.
Published: February 2004

A concept for the electrical detection of a biological interaction is proposed, mainly based on the conductance variation of a nanometer size-gap (typically less than 100 nm) between two planar electrodes. A functionalized surface was used in the vicinity of the gap in order to concentrate the ligand/receptor complex between the electrodes. The chemistry chosen for the immobilization of the ligand on the biosensor surface is compatible with peptide structures. The receptor in solution was labeled with gold particles which can be inserted into the gap. A significant conductance variation was observed without having to use a silver enhancer solution in the case of biotin/streptavidin or biotin/antibiotin antibodies model ligand/receptor interactions.
Optical properties of the nitrogen vacancy in AlN epilayers
Authors: Nepal N. , Nam K. B. , Nakarmi M. L. , Lin J. Y. , Jiang H. X. , Zavada J. M. , Wilson R. G.
Published: February 2004

AlN epilayers grown by metalorganic chemical vapor deposition were implanted with cobalt ions and studied by deep UV photoluminescence (PL). A PL emission peak at 5.87 eV (at 10 K) was observed for the Co-implanted AlN epilayers, which was absent in as-grown AlN epilayers. Temperature dependence of the PL intensity of the 5.87 eV emission line revealed an ion-implantation induced defect with energy level of about 260 meV below the conduction band. The 5.87 eV emission line is believed due to a band-to-impurity transition involving the nitrogen vacancy (VN) in ion-implanted AlN. The experimentally determined energy level of the nitrogen vacancy is in reasonable agreement with the calculated value of 300 meV. From the band-to-impurity transition involving VN, we have deduced the energy band gap of AlN to be 6.13 eV, which is consistent with our previous result. Our results suggest that nitrogen vacancies in AlN cannot make any significant contribution to the n-type conductivity due to the large binding energy as well as the large formation energy.
Information needs of people with multiple sclerosis and the implications for information provision based on a national UK survey
Authors: Hepworth Mark , Harrison Janet , James Nicole
Published: February 2004

Qualitative and quantitative methods were used to study the information needs of people with multiple sclerosis (MS) in the UK. Categories of information need were identified; their importance and difficulty in obtaining them quantified. The research highlighted how there were significant differences in terms of people’s desire for the information, the topics in which they were interested and how they wanted that information. Information provision to people with MS was found to have improved dramatically over the last seven years, but was found to be inconsistent in terms of subjects covered. However, it should be borne in mind that it may be difficult for people to take on board information for a variety of reasons. Furthermore, different individual needs mean that information provision is a complex task. Many intervening factors can make it fail. The research made it clear how access to relevant information, provided in an appropriate way, could significantly improve the quality of life of the person with MS and that there is considerable scope for improving provision of information to people with MS.
Health information on the Internet: a qualitative study of NHS Direct Online users
Authors: Williams Peter , Nicholas David , Huntington Paul
Published: February 2004

Examines the way the general public exploits the Internet for health information, the motives behind usage, attitudes towards issues such as quality concerns, and the extent to which Internet interventions affect the doctor‐patient relationship. Although a questionnaire survey was used (posted on the NHS Direct Web site), the questions asked were open, and invited free‐text “qualitative” answers. This method was a success in terms of the amount and richness of the data accrued. Results suggested that the Internet is exploited in a wide variety of ways, by users acting in a number of roles – patient, intermediary or professional. Some health professionals are now so comfortable with the Internet that they encourage Internet usage by their patients. Lay users demonstrated a high level of understanding of issues raised, and showed a (healthy?) scepticism regarding the information provided. Many users felt that their consultations with doctors had been enriched by Internet‐acquired information.
Availability and use of information touch‐screen kiosks (to facilitate social inclusion)
Authors: Boudioni Markella
Published: February 2004

The availability and the use of touch‐screen systems for accessing a range of information in different settings in the UK, in particular from socially excluded groups, are reviewed. A literature review and consultations with stakeholders are conducted. Touch‐screens are used widely by the Department of Works and Pensions; they are used for community services on a much smaller scale. NHS Direct provides the largest number of kiosks for health information and promotion; InTouch with Health, Wellpoint Health Centres, Patient Information for Consent Systems are some other examples. Some projects that target socially excluded groups are identified. Factors that determine usage and contribute to successful usage are also identified. The majority of stakeholders express the view that kiosks should be available in a variety of locations, irrespective of their specific content and information.
Digital interactive television: health information platform of the future?
Authors: Gunter Barrie , Nicholas David , Huntington Paul , Williams Peter
Published: February 2004

Presents research that was designed to explore the early take‐up of a pilot digital interactive television (DiTV) health information service (Living Health) by cable television subscribers in Birmingham, UK. Log data indicated real‐time viewing behaviour of subscribers to the cable network on which the digital health service was carried. A survey of users delivered a return sample of 723 subscribers. Log data indicated an initial surge in use that subsided and stabilised at a lower level. Over one third of cable network subscribers visited the digital health TV site at least once during a 20‐week pilot period. The most popularly visited pages concerned sex‐related information. In the user survey, just under one in four respondents had reportedly used the DiTV service. The user profile was oriented towards older men and young adult women. Over eight in ten users found the service easy to use and understand. Over half of users consulted the service in connection with a GP visit. Some evidence emerged that use of DiTV might substitute for consulting a doctor among some users.
Using the virtual learning environment WebCT to enhance information skills teaching at Coventry University
Authors: Patalong Sally
Published: February 2004

This paper describes the use of the virtual learning environment WebCT to respond to a number of challenges in user education work at the University of Coventry. The effectiveness of the VLE‐based method of delivering information skills training was evaluated over two years. Certain problems, were ironed out between year one and year two of the implementation of the information skills course. This led to a seeming decline in reported achievement levels between the two years. However, such diminishing of learning outcomes was more apparent than real, and masked the importance of putting in place a more reliable teaching method, one in which students become responsible for their own learning. It was concluded that this method of carrying out user education did succeed in effectively enabling larger numbers of students than before to learn information skills and at a variety of times in the academic year that are suitable to them. The goal of gaining recognition for information skills in the University at large and having these skills integrated into the curriculum is also moving nearer as a result of this work.
Recent innovations in cultured milk products for infants
Authors: Sarkar S.
Published: February 2004

Breast milk is considered superior over other modified infant formulae owing to its numerous intrinsic characteristics and pre‐eminence. However, breast milk is nutritionally inadequate for low‐birth weight infants and infants fed exclusively on breast milk are at the risk of getting infected with HIV‐1 and transmitted drugs in breast milk due to sterility of mothers at the time of pregnancy. In absence or insufficient secretion, breast milk stored at human milk banks or various developed infant formulae may be a practical substitute. Microbiological safety of breast milk from human milk banks is governed by the conditions of its collection and storage, whereas method of reconstitution and sterilization of equipments influences the quality of infant formulae. Under this circumstances various specially developed cultured milk products can be recommended for feeding both normal and sick infants. This paper enlightens the recent research innovations in the field of cultured milk products for feeding infants in absence of breast milk.
Potential of acidophilus milk to lower cholesterol
Authors: Sarkar S.
Published: February 2004

An attempt has been made to highlight the recent literature related to the hypocholesterolemic effect of acidophilus milk. Higher levels of serum cholesterol are often associated with cardiovascular diseases. Concentration of cholesterol can be kept lower by encouraging intake of polyunsaturated and monosaturated fatty acids and discouraging saturated fatty acids. Lactobacillus acidophilus, being the natural inhabitant of intestine and possessing bile‐salt hydrolase activity, can be exploited during the manufacture of acidophilus milk and its application as a means for reducing cholesterol level is recommended. Factors influencing the efficacy of acidophilus milk to lower serum cholesterol are type of milk employed for product manufacture, age, sex, food habits and initial concentration of cholesterol of test subjects. Consumption of acidophilus milk as a dietary adjunct can be recommended.
The greening of libraries
Authors: Ephraim Philip E.
Published: February 2004

Postulates the theory of Green Library Management as it applies to the key functions of the library. This theory has been put into practice at the University of Mauritius Library. Reviews some of the “green” measures applied in the administration of the Reference Library and makes further proposals. In integrating the concepts of sustainability, it draws attention to the need for a meeting point between the principles of environmental studies and library studies in the merging modern library management process.
Haptic robots help solve design issues
Authors: Kochan Anna
Published: February 2004

New haptic robot arms with powerful force feedback could help product design engineers check out complex assembly problems in a virtual reality environment. Companies in the automotive and aerospace industries are likely to be the first to take advantage of the technology. They could be applying it to design‐for‐assembly projects by 2005.
Helping older workers cope with continuous quality improvement
Authors: Kidwell Roland E.
Published: February 2004

When organizations implement continuous quality improvement (CQI) programs, managers and employees are faced with massive change, often requiring a renegotiation of the psychological contract between employer and employee. This paper discusses generational differences in reactions to major change initiatives as well as change management issues in public and nonprofit organizations. Its specific focus is an organizational unit in the nonprofit sector whose CQI program, which required more employee involvement, was met with varied reactions among older veterans of its small workforce. Observations of the unit and its employees are used to develop a typology of reactions to major change among long‐time, older workers. Strategies are provided to managers who must develop methods to deal with adverse reactions to major organizational changes such as CQI. The typology may be useful to management development specialists who are attempting to transform organizations with significant age diversity.
The fight against SARS: a backfilling connection for the prevention of drying out of floor drains' U‐traps
Authors: Yuen K.K. , Lee Eric W.M. , Lo S.M.
Published: February 2004

Severe acute respiratory syndrome (SARS) was first reported in China in November 2002 and had spread to Hong Kong by late February 2003. Initially hospitals were the main sites of the infection which was thought to be due to an airborne virus. However the spread of the virus to large residential tower blocks led authorities to suspect that the evaporation of toilet floor drain U‐traps may be a possible way of spreading the virus. The paper reports a full scale rig testing of methods to prevent the evaporation of the U‐trap water seals and concludes with recommendations for further research.
Benchmarks to minimize water leakages in basements
Authors: Chew M.Y.L. , De Silva Nayanthara
Published: February 2004

Basement defects such as water seepages/leakages are tedious and expensive to rectify. Intensive research has been conducted to study the problem type, their causes and preventive measures. The study explored 987 water seepage/leakage cases in 61 buildings. Eleven significant factors leading to the occurrence of water seepage in basements were identified. The implications of six benchmarks, namely: degree of water‐tightness; safety measures for structural concrete; performance of waterproofing systems; integrity of basement structure; provision for movement and quality of compaction in concreting, for minimizing four types of water seepage/leakage problems in basements are discussed.
Flexural behaviour of concrete beams internally reinforced with GFRP rods and steel rebars
Authors: Leung H.Y. , Balendran R.V.
Published: February 2004

Use of fibre‐reinforced polymer (FRP) composite rods, in lieu of steel rebars, as the main flexural reinforcements in reinforced concrete (RC) beams have recently been suggested by many researchers. However, the development of FRP RC beam design is still stagnant in the construction industry and this may be attributed to a number of reasons such as the high cost of FRP rods compared to steel rebars and the reduced member ductility due to the brittleness of FRP rods. To resolve these problems, one of the possible methods is to adopt both FRP rods and steel rebars to internally reinforce the concrete members. The effectiveness of this new reinforcing system remains problematic and continued research in this area is needed. An experimental study on the load‐deflection behaviour of concrete beams internally reinforced with glass fibre‐reinforced polymer (GFRP) rods and steel rebars was therefore conducted and some important findings are summarized in this paper.
Consumer behaviour in the valuation of residential property
Authors: Daly Jacqui , Gronow Stuart , Jenkins Dave , Plimmer Frances
Published: February 2004

This paper reports the results of empirical investigations that examine behavioural aspects of residential property valuations. Following the house price collapse of the late 1980s in the UK, there was considerable criticism of the valuation methods used by residential valuers. In particular for the current research, the valuation methods employed by valuers had not taken account of buyer behaviour in the valuation process, which contributed to inaccurate valuations. This research investigates both the attitudes of the consumers of residential property and the actual valuation methods used by valuers to determine whether they account for buyer behaviour accurately. The study was undertaken on a cross‐national comparative basis in the UK, Ireland and Australia and pursued on a qualitative basis. Overall, the research concludes that although valuers believe that buyer behaviour is an important part of the valuation process they simply do not consider buyer preferences. In effect, valuers have reduced the valuation task to a confirmation of bid price and, because of lender pressure which occurs worldwide, valuers overlook the economic sustainability of the property asset, which has severe implications for housing markets and national economies that interact with these markets.
Electronic governance for the Lands and Surveys Department in Cyprus
Authors: Andrea Panayiotou Panayiotis
Published: February 2004

This research work examines existing electronic governance (eGov) systems in the area of interest of land registry, and investigates products and benefits provided to users, along with their policy of pricing. It analyses the eEurope initiative and the strategy of Cyprus regarding electronic access to public services. In addition, it proposes principles for the introduction of an eGov system in the field of business operations and the sphere of responsibility of the Lands and Surveys Department in Cyprus (DLS) and suggests basic amendments at land legislation. Furthermore, this study makes recommendations to the DLS, so that it could improve its productivity, the efficiency and effectiveness of services to citizens and business as well as to maximise its contribution in the development of the wider electronic Cyprus (eCyprus).