bluuebunny/crossref_metadata_2025 huggingface dataset:
Endocytotic Function for Syntaxin 1A
Authors: Ray L. Bryan
Published: September 2006

Syntaxin 1A is a plasma membrane protein of the SNARE (soluble
N
-ethylmaleimide-sensitive factor attachment protein receptor) family, well known for its essential roles in neuronal signaling in which it regulates trafficking, docking, and fusion of synaptic vesicles with the plasma membrane. Experiments from Yu
et al
. show that syntaxin 1A also has a role in internalization of vesicles containing a transporter for the neurotransmitter glutamate. Transport of glutamate is important to prevent excessive stimulation of glutamate receptors and to maintain the supply of glutamate for conversion to the inhibitory neurotransmitter GABA (γ-aminobutyric acid). Yu
et al
. showed that in rat C6 glioma cells, expression of transfected syntaxin 1A decreased glutamate transport and the abundance of the glutamate transporter EAAC1 (excitatory amino acid carrier 1) at the cell surface. Depletion of syntaxin 1A with small interference RNA increased the abundance of EEAC1 at the cell surface and increased glutamate transport. Excessive stimulation of cells with the glutamatergic agonist kainic acid (KA) reproduces effects seen in epilepsy. The authors tracked biotinylated EAAC1 in KA-treated cells and found that suppression of syntaxin 1A expression reduced KA-stimulated internalization of EAAC1 into an endosomal or lysosomal compartment. The results suggest, as the authors put it, that syntaxin 1A must now be considered to regulate "both the ‘ins’ and the ‘outs’ of synaptic neurotransmission."

Y.-X. Yu, L. Shen, P. Xia, Y.-W. Tang, L. Bao, G. Pei, Syntaxin 1A promotes the endocytic sorting of EAAC1 leading to inhibition of glutamate transport.
J. Cell Sci.
119
, 3776-3787 (2006).
[Abstract]
[Full Text]
Phosphatidylserine Recruits Rac1
Authors: Gough Nancy R.
Published: September 2006

Rac1 is a member of the Rho family of guanosine triphosphatases (GTPases) and is involved in stimulating membrane ruffling and cell migration. Finkielstein
et al
. show, using liposome-binding assays, nuclear magnetic resonance assays, and lipid overlay assays, that purified Rac1, either prenylated or nonprenylated, GTP-bound or GDP-bound, interacts specifically with phosphatidylserine, an anionic lipid that is abundant on the inner leaflet of the plasma membrane. Surface plasmon resonance assays demonstrated that prenylated Rac1 had a higher affinity for phosphatidylserine than did nonprenylated Rac1. The interaction required the polybasic motif (PBM), and mutation of a lysine and an arginine (K186A/R187A) abolished Rac1 binding to phosphatidylserine. Cells expressing the K186A/R187A mutant showed an altered distribution of Rac1 that was located in cytosolic puncta, which may reflect binding to internal membranes, instead of the plasma membrane. Exposure of cells transfected with wild-type or various Rac1 mutants to phosphatidylserine caused membrane ruffling, formation of filopodia, and reduction in actin stress fibers and stimulated cell migration in a wound assay. Each response required Rac1 GTPase activity and an intact PBM. Exposure of the transfected cells to phosphatidylserine stimulated the translocation of Rac1 to the plasma membrane, Rac1 GTP loading, activation of Cdc42 (a Rho GTPase that is downstream of Rac1), and activation of the mitogen-activated protein kinase kinase (MEK1). The authors propose that, as with Src, Raf-1, and KRas4B, the PBM allows targeting of Rac1 to specific regions of the plasma membrane through the interactions with phosphatidylserine, thereby facilitating the interaction of Rac1 with its regulators and effectors.

C. V. Finkielstein, M. Overduin, D. G. S. Capelluto, Cell migration and signaling specificity is determined by the phosphatidylserine recognition motif of Rac1.
J. Biol. Chem.
281
, 27317-27326 (2006).
[Abstract]
[Full Text]
How Nickel Binding Regulates Transcription
Authors: Ray L. Bryan
Published: September 2006

Bacteria, such as
Escherichia coli
, have enzymes that require nickel ions, and they express a nickel transporter to acquire the metal from the environment. To keep cellular concentrations of nickel relatively constant, the expression of the transporter is regulated by a repressor, NikR, which is itself a nickel sensor. NikR binds to the operator of the transporter gene and represses transcription only when it is in the nickel-bound form. Schreiter
et al
. solved the crystal structures of the nickel-bound form of NikR from
E. coli
both alone and in a complex with a DNA fragment corresponding to the promoter of the nickel transporter gene. The protein has two DNA-binding domains that interact with sites in the palindromic operator on either side of a metal-binding domain (MBD). In other ligand-regulated transcription factors, activation is proposed to occur when a change in the spacing between the DNA-binding domains is altered such that they interact more effectively with the promoter DNA. Comparison of the new structures with the previously reported structure of nickel-free protein indicates that this is not how NikR works. The allosteric changes that occur when metal binds do not appear to put the DNA binding domains into position for interaction with the promoter. Rather, they appear to create a new interactive surface within the metal binding domain that enhances the interaction of the protein with the promoter DNA helix. Changes in the protein structure appear to generate a second metal binding site as well, which may decrease flexibility of the protein and hold it in a conformation that more efficiently binds DNA. The results provide a detailed look at the precise molecular changes that underlie transcriptional control by a ligand-regulated transcription factor.

E. R. Schreiter, S. C. Wang, D. B. Zamble, C. L. Drennan, NikR–operator complex structure and the mechanism of repressor activation by metal ions.
Proc. Natl. Acad. Sci. U.S.A.
103
, 13676-13681 (2006).
[Abstract]
[Full Text]
Identifying the CRAC Channel
Authors: Adler Elizabeth M.
Published: September 2006

Release of Ca
2+
from intracellular stores elicits Ca
2+
entry through plasma membrane Ca
2+
release-activated Ca
2+
(CRAC) channels. Stromal interaction molecule (Stim in
Drosophila
, STIM1 in mammals) and Orai (in
Drosophila
, Orai1 in humans, also known as CRACM1) have been implicated in mediating the CRAC current; however, the precise relation of Orai to the CRAC channel has been unclear. Two groups now use mutational analysis to identify Orai as forming the CRAC channel pore subunit. Yeromin
et al
. overexpressed wild-type or mutant Orai together with Stim in S1 cells. Store depletion promoted association of the wild-type proteins and elicited a large CRAC current; coexpression of Stim with Orai mutants altered CRAC current properties. A glutamate to aspartate mutation at position 180 (E180D) altered ion selectivity and rectification; a glutamate to alanine mutation at the same location acted as a dominant negative to block native CRAC current; and mutations of aspartate to alanine at 184 and 186 or asparagine to alanine at 188 reduced sensitivity to Gd
3+
block. Prakirya
et al
. used both biotinylation with a cell-impermeant reagent and immunocytochemical staining of tagged Orai1 expressed in human embryonic kidney (HEK) 293 cells to show that it was a plasma membrane protein. They found that a glutamate to alanine mutation at position 106 (E106D, corresponding to Yeromin
et al
.’s E180D mutation) altered ion selectivity of Orai1 expressed in T cells deficient in CRAC current and Ca
2+
-influx, as did a glutamate to glutamine mutation at position 190. Thus, both groups conclude that Orai forms the CRAC channel pore subunit.

M. Prakriya, S. Feske, Y. Gwack, S. Srikanth, A. Rao, P. G. Hogan, Orai1 is an essential pore subunit of the CRAC channel.
Nature
443
, 230-233 (2006).
[PubMed]

A. V. Yeromin, S. L. Zhang, W. Jiang, Y. Yu, O. Safrina, M. D. Cahalan, Molecular identification of the CRAC channel by altered ion selectivity in a mutant of Orai.
Nature
443
, 226-229 (2006).
[PubMed]
Of Aging and Aggregation
Authors: Chong Lisa D.
Published: September 2006

Protein aggregation that is associated with late age onset diseases such as Alzheimer’s and Parkinson’s has toxic effects. Cohen
et al
. show, in a worm model of amyloidosis, that the aging process is linked to toxic protein aggregation. Molecules associated with the insulin signaling pathway--a cascade that is linked to aging--also influence aggregation and toxicity. The transcription factor DAF-16 and heat shock protein HSF-1 function to promote aggregation or disaggregation, respectively, of β-amyloid peptides. The authors propose a cellular mechanism hinging on these two factors whereby toxic aggregates are identified and prepared for disaggregation and degradation.

E. Cohen, J. Bieschke, R. M. Perciavalle, J. W. Kelly, A. Dillin, Opposing activities protect against age-onset proteotoxicity.
Science
313
, 1604-1610 (2006).
[Abstract]
[Full Text]
A PAVING THEOREM FOR AMENABLE DISCRETE KAC ALGEBRAS
Authors: TOMATSU REIJI
Published: September 2006

We extend the Ornstein–Weiss theorem on paving of amenable discrete groups to amenable discrete Kac algebras.
A LOGARITHMIC GENERALIZATION OF TENSOR PRODUCT THEORY FOR MODULES FOR A VERTEX OPERATOR ALGEBRA
Authors: HUANG YI-ZHI , LEPOWSKY JAMES , ZHANG LIN
Published: September 2006

We describe a logarithmic tensor product theory for certain module categories for a "conformal vertex algebra". In this theory, which is a natural, although intricate, generalization of earlier work of Huang and Lepowsky, we do not require the module categories to be semisimple, and we accommodate modules with generalized weight spaces. The corresponding intertwining operators contain logarithms of the variables.
THE UNEXPECTED ASPECTS OF SURPRISE
Authors: LORINI EMILIANO , CASTELFRANCHI CRISTIANO
Published: September 2006

Some symbolic AI models, for example, BDI (belief, desire, intention) models are conceived as explicit and operational models of the intentional pursuit and belief dynamics. The main concern of these models is to provide a clear understanding of the functional roles of different kinds of epistemic and motivational states (beliefs, acceptances, expectations, intentions, goals, desires, etc. …), of the relational properties among them. Mental configurations of appraisal (involving different kinds of motivational and epistemic states) which correspond to particular cognitive emotions such as disappointment, fear, relief, shame, etc. … have been analyzed by several authors close to the BDI theoretical tradition. The main objective of this work is a formal analysis of Surprise in a BDI-like cognitive architecture. A clarification of the functional role of Surprise in a BDI-like cognitive architecture with respect to resource bounded belief revision is given.
BAYESIAN PROPAGATION FOR PERCEIVING MOVING OBJECTS
Authors: BOCCIGNONE GIUSEPPE , MARCELLI ANGELO , NAPOLETANO PAOLO , CAGGIANO VITTORIO , DI FIORE GIANLUCA
Published: September 2006

In this paper we address the issue of how form and motion can be integrated in order to provide suitable information to attentively track multiple moving objects. Such integration is designed in a Bayesian framework, and a Belief Propagation technique is exploited to perform coherent form/motion labeling of regions of the observed scene. Experiments on both synthetic and real data are presented and discussed.
CONTENT-BASED IMAGE RETRIEVAL BY A FUZZY SCALE-SPACE APPROACH
Authors: CECCARELLI MICHELE , MUSACCHIA FRANCESCO , PETROSINO ALFREDO
Published: September 2006

Image descriptions aimed at the realization of content-based image retrieval (CBIR) should include the vagueness of both data representations and user queries. Here we show how multiscale textural gradient can be used as an efficient visual cue for image description. This feature has been already efficiently used in problems of image segmentation and texture separation. Our main idea is based on the assumption that, for image description, shape and textures should be considered together within a unified model. We report an efficient image description algorithm where the multiscale analysis is modeled by a differential morphological filter. Experiments with large image databases and comparisons with classical methods are reported.
ESTIMATING FACIAL ALBEDO FROM A SINGLE IMAGE
Authors: SMITH WILLIAM A. P. , HANCOCK EDWIN R.
Published: September 2006

This paper describes how a facial albedo map can be recovered from a single image using a statistical model that captures variations in surface normal direction. We fit the model to intensity data using constraints on the surface normal direction provided by Lambert's law and then use the differences between observed and reconstructed image brightness to estimate the albedo. We show that this process is stable under varying illumination. We then show how eigenfaces trained on albedo maps may provide a better representation for illumination insensitive recognition than those trained on raw image intensity.
DOES ORGANIZATION STRUCTURE MATTER? ON THE RELATIONSHIP BETWEEN THE STRUCTURE, FUNCTIONING AND EFFECTIVENESS
Authors: ANDERSEN JON AARUM , JONSSON PATRIK
Published: September 2006

Managers often see new organizational design as the solution to many problems. This paper explores the relationship between organization structure (design), functioning of organizations, and effectiveness. A study of 320 companies showed that the structural variable, decentralization, marginally affected the way in which organizations function. Functional variables had a minor impact on profitability. No direct relationship between structure and effectiveness was found. When functioning is conceptualized as a mediating factor no direct causality between structure and effectiveness is implied, but a relationship between structure, function and effectiveness. To improve effectiveness, reorganizing is probably not the first option to consider.
HOW DO FIRM-SPECIFIC ORGANIZATIONAL CAPITAL AND OTHER INTANGIBLES AFFECT SALES, VALUE AND PRODUCTIVITY? EVIDENCE FROM JAPANESE FIRM-LEVEL DATA
Authors: RAMIREZ PABLO GONZALO , HACHIYA TOYOHIKO
Published: September 2006

Over the past decades, the diffusion of new technological innovations has transformed the economies. In particular, the strategic emphasis shifted from efficient management of tangibles assets to innovation and effective usage of intangible assets. In this study we explore how the various combinations of sort of intangibles assets, like firm-specific organizational capital (FSOC), technology, brand, human and social capital affect the firm's corporate performance. The results suggest that regardless of the firms' type, those with higher stocks of FSOC, human and social capital outperform firms with higher stocks in only one dimension, suggesting a high degree of complementarity between them. The results also indicate that intangibles like FSOC and human and social capital are more likely to impact on productivity, whereas R&D and advertising are more likely to impact on the firm's value.
NEW PRODUCT DEVELOPMENT WITHIN SMALL AND MEDIUM-SIZED ENTERPRISES: ANALYSIS THROUGH TECHNOLOGY MANAGEMENT MAPS
Authors: MILLWARD HUW , BYRNE CHRIS , WALTERS ANDREW , LEWIS ALAN
Published: September 2006

Technology management maps have been developed to evaluate new product development (NPD) within small and medium-sized enterprises (SMEs). These maps provide a graphical 'footprint' of a company in terms of knowledge, resources, quality, and innovation & change. A series of 15 case-study companies highlight that the shape and extent of the technology management maps correlate well with the overall impact of the NPD activities. Implementation of an effective NPD process is the main distinguishing factor between the best- and worst-performing companies. The inherent benefits of design-led technology are also encapsulated, specifically in the areas of resource savings and improved product quality.
SUSTAINABLE DEVELOPMENT OBJECTIVES IN IMPACT ASSESSMENT: WHY ARE THEY NEEDED AND WHERE DO THEY COME FROM?
Authors: HACKING THEOPHILUS , GUTHRIE PETER
Published: September 2006

The established approach to impact assessment is baseline-led, whereby the conditions that are likely to prevail in the absence of a proposed initiative are used as the "benchmarks" for determining the significance of impacts. Proponents of sustainable development (SD) criticise this approach for being directionless since it is based on extrapolating the past with no clear vision of what should be achieved in the future. Establishing objectives by which SD can be defined is one of the greatest challenges in the development of objectives-led assessment, especially since there is still so little consensus regarding exactly what SD entails. This paper explores a number of methods for establishing SD objectives based on a literature review and the analysis of case studies.
The Dielectric Property of Polystyrene and Some Ring-substituted Polystyrenes in Glassy State
Authors: Nozaki Masaoki , Shimada Kunihiko , Okamoto Shigeharu
Published: September 2006

Measurements of dielectric properties of polystyrene and some substituted polystyrenes containing different substituents (methyl group and halogen atoms) in the phenyl ring are carried out over a temperature range from 93 to 343°K in vacuo (10-3 mmHg) at 1 and 10 kHz. The temperature dependence of dielectric loss ε'' is mardedly different according to the location of the substituent in the ring. The dielectric behavior of these polymers at temperatures around 150°K at 10 kHz is explained in terms of two modes of phenyl group motions: the hindered rotation of phenyl group around the bond to the main chain and the oscillation or wagging of phenyl rings. The relaxation observed as a shoulder at the foot of the α-loss peak in the ε''-temperature curve is attributed to the local-mode oscillation of the main chain.
Epitaxial Growth of Semi-Insulating Gallium Arsenide
Authors: Mizuno Osamu , Kikuchi Sadao , Seki Yasuo
Published: September 2006

Semi-insulating gallium arsenide is grown epitaxially from the vapor phase by using chromyl chloride as a doping agent. The resistivity of the epitaxial layer is greater than 108 Ω·cm at room temperature. The temperature dependence of the resistivity gives an activation energy of 0.63 eV.
Multilayer structure consisting of semi-insulating layer and n-type layer is obtained without halting growth process by flowing and stopping the chromyl chloride vapor. No dislocation is observed at the boundary between semi-insulating layer and n-type layer, though many dislocations are observed at the epitaxial-substrate interface.
It is found that the grown layer becomes semi-insulating only when the donor concentration of the layer is lower than 5×1015 cm-3.
On the Aberration of Spectacle Lens
Authors: Kubota Hiroshi
Published: September 2006

It has been recognized that astigmatism has to be eliminated in spectacle lenses. It is shown in the present work, however, that a spectacle lens free from astigmatism can be, and usually is, accompanied by coma of a considerable magnitude. Calculations of astigmatism and coma are carried out by means of an electronic computer. The results are given in contour maps. A method for designing good spectacle lenses based on these maps is described.
Grain Boundary States in Silicon and Germanium
Authors: Matsukura Yasuo
Published: September 2006

Bicrystals of n- and p-type silicon and p-type germanium with relatively large tilt angles are grown from the melt, while some bicrystals of silicon are prepared by floating zone technique. From measurements of the photoresponse and the current-voltage characteristics across the grain boundary and the Hall effect for current flow along the grain boundary, it is concluded that the grain boundaries of p- and n-type silicon bicrystals are of n- and n- type respectively. Similar measurements are performed on p- type germanium bicrystals. It is shown that the grain boundary states of silicon bicrystals are located above the middle of the forbidden band, and pick up both electrons and holes, independently of the oxygen content. The boundary states of germanium bicrystals, lying below the middle of the forbidden band, accept only the electrons exclusively and form a p
p
+
p structure at the grain boundary at 300°K.
Energy Spectra of Electrons Emerging from Lead Exposed to 320 kVp White X-rays
Authors: Inada T. , Kawashima K. , Hoshino K. , Matsuzawa H.
Published: September 2006

The energy spectra of secondary electrons, which emerge perpendicularly from a lead-foil exposed to 320 kVp therapeutic white x-rays (HVL=3 mmCu), are observed by a double-focusing magnetic beta-spectrometer. For the foil thicknesses 0.4–34 mg/cm2 and the x-ray incident angles less than 80°, the emerging electrons are found in the energy region less than 220keV with the maximum counts at 50–80 keV (mean energy: 75–100 keV). For a given foil thickness, the spectral shape is almost independent of the incident angle of x-rays. With the increase in foil thicknesses, however, the high-energy part of the spectra is markedly intensified.
Energy Transfer Mechanism and Amplified Spontaneous Emission Characteristics of Dye Mixture Solutions
Authors: Terada Mitsugu , Ohba Yujiro
Published: September 2006

The excitation energy transfer mechanism in a dye laser system is discussed. The rate constants of the radiative and radiationless deactivation processes of the donor dye are estimated for two kinds of donor-acceptor dye mixture solutions. It is found that the suitable energy transfer mechanism depends on the characteristics of the excitation source and of the fluorescence of the donor dye. When a dye mixture solution is pumped by a short-pulse excitation source, the excitation energy is transferred most effectively by resonant transfer. Experimental results are also reported on the amplified spontaneous emission characteristics of dye mixture solutions.
Comparison of Multi-Beam and Single-Beam Cytofluorometers for an Automated Screening System in Gynecologic Cytology
Authors: Fujii Ken-ichi , Suzuki Norihito
Published: September 2006

Clumps of cells often give a false nuclear fluorescence intensity in a measuring system using flow cytofluorometry. In this study, we examined signal selection procedures in multi-beam and single-beam cytofluorometers with the aim of eliminating such false signals. The signal selection in the multi-beam cytofluorometer was found to be far superior to that in a single-beam cytofluorometer, and the problem of false nuclear fluorescence intensity is effectively obviated by using the former type of cytofluarometer.
Electrical Properties of SnO2 Polycrystalline Thin Films and Single Crystals Exposed to O2- and H2-Gases
Authors: Yamazaki Toshinari , Mizutani Uichiro , Iwama Yoshiro
Published: September 2006

The electrical conductivity σ and carrier density n have been measured in the range 77–670 K for the SnO2 single crystal and thin films prepared by the vapour deposition technique. It is found that the SnO2 thin film possesses a carrier density of 1019 cm-3, three orders of magnitude larger than that in the as-grown SnO2 single crystal, and exhibits electrical properties characteristic of a degenerate semiconductor. Both single crystals and thin films undergo irreversible changes in electrical properties upon heat treatment in vacuum or exposure to O2- or H2-gases. This occurs as a result of reduction and oxidation of SnO2. However, the oxidation and reduction proceed in thin films at much lower temperatures than in single crystals. The unique gas-sensing character of thin films was interpreted by assuming that the oxidation and reduction preferentially proceed along the grain boundaries in the thin film.
Simple Method of Calculating Phonon-Assisted Auger Recombination Rate in Direct-Gap Semiconductors
Authors: Takeshima Masumi
Published: September 2006

A simple but approximate method is developed for calculating the phonon-assisted Auger recombination rate indirect-gap semiconductors, whose analysis is rigorously based on the Green's function formalism. The method is especially useful for analyzing loss mechanisms in a semiconductor laser which is made of a nondoped or a moderately doped layer. The usefulness of the method is demonstrated though the rigorous and the approximate calculations for typical materials GaAs, InP, GaSb and InAs. The condition, under which the early theory based on the second-order perturbation treatment is useful, shows up through a characteristic function. A brief discussion is also given of experiments.
PbO/Cd(S, Se): Cu Mixed Photoconductor System for Electrophotography
Authors: Pillai Navneet
Published: September 2006

A mixed system, consisting of Lead monoxide (PbO) and Cadmium Sulfo selenide Cd (S, Se): Cu in Acrylonitrile-Butadiene-Stytene (ABS) binder resin has been inevstigated with respect to electrophotographic characteristics. PbO and Cd (S, Se): Cu in 80: 20 composition (by weight), when dispersed in ABS binder, (30% by weight) give optimum values for various electrophotographic parameters. Charge acceptance, dark and photo induced decay, contrast potential and spectroresponse were the important electrophotographic properties, studied. The acceptance potential of the charged layer was 1092 volts. The fractional dark decay (observed 60 seconds after the charging) and fractional photo induced decay (observed 10 seconds after the start of illumination) were 35.5% and 79.4% respectively. The intensity of illumination was 4.5 mW/cm2. The absorption spectrum of the material spreads over a wide range covering UV as well as visible region.
Theoretical Analysis of Amorphous-Silicon Field-Effect-Transistors
Authors: Kishida Satoru , Naruke Yasuo , Uchida Yasutaka , Matsumura Masakiyo
Published: September 2006

Static characteristics of amorphous-silicon field-effect transistors have been analyzed under the assumption that the localized state density distribution (LSDD) in amorphous-silicon with respect to energy takes on an exponential or uniform form. In the case of an exponential LSDD, logarithmic drain current I
D vs logarithmic gate voltage V
G characteristics of the FET for large V
G is found to be linear, the slope of which yields the characteristic temperature of the exponential LSDD. While, in the case of a uniform LSDD, log
(I
D
V
G)–V
G curves for large V
G are found to be linear. The experimental data is qualitatively in good agreement with the theoretical results of the exponential LSDD.
Bunched Beam Instability Associated with Cavity Impedance
Authors: Nishimura Hiroshi
Published: September 2006

Investigation is made on the longitudinal single bunch instability of the electron beam in a high energy storage ring. It is shown that the Robinson instability of a parasitic mode is caused by the interaction between a higher order synchrotron oscillation and a higher order resonate mode of an RF cavity. Two damping mechanisms, the Landau damping and the radiation damping, are investigated and the stability criteria are obtained.
Temperatures in Imploding Detonation Waves
Authors: Terao Kunio
Published: September 2006

The spectroscopic and electron temperatures in spherically-imploding detonations in a stoichiometric propane-oxygen mixture were measured and the gas temperature behind the shock waves at cylindrical and spherical implosion fronts was estimated from the probability of triple shock formation. Both the spectroscopic and electron temperatures increase with the propagation of detonation as rapidly as the pressure. The temperature behind the shock waves is in agreement with the theoretical value. The results suggest that the high-pressure peak appears not behind the shock waves but in the combustion zone of the detonation. The reason for this is attributed to reactions caused by shock waves reflected at the vessel wall releasing more heat than in normal combustion, by other exothermic processes such as recombination.
A Localized Defect in InP with Strong Temperature Dependence of Capture Cross-Section
Authors: Ogura Mototsugu , Mizuta Masashi , Kukimoto Hiroshi
Published: September 2006

The properties of the localized deep-level MOE2 in InP have been investigated. The electron capture cross-section has a strong temperature dependence in the temperature range from 222 K to 276 K. A thermal depth of E
t=0.15 eV and an optical depth of E
opt=0.48 eV have been obtained for MOE2 by normal and optical deep-level transient spectroscopy (DLTS). These results indicate that a Stokes shift, which is characteristic of strong electron-phonon coupling, occurs at the MOE2 level. The experimental results on the temperature-dependent capture cross-section can be explained fairly well by the recently-formulated multiphonon emission electron capture mechanism.
Polysilicon Super-Thin-Film Transistor (SFT)
Authors: Hayashi Hisao , Noguchi Takashi , Oshima Takefumi
Published: September 2006

N-channel MOS FET's have been fabricated in super-thin polysilicon film on quartz substrate. The thickness of the film had an important role in improving the electrical properties. Moreover, grain boundary passivation by the hydrogen from a plasma-SiN film has been developed to increase the field effect mobility. The field effect mobility is more than 20 cm2/V·s at the polysilicon thickness of 150–200 Å; and threshold voltage and leakage current are reduced to 6 V and 10-13 A/µm, respectively. The device obtained in this work can be used not only for flat panel matrix displays but also for other applications.
Growth of Single Domain GaAs Layer on (100)-Oriented Si Substrate by MOCVD
Authors: Akiyama Masahiro , Kawarada Yoshihiro , Kaminishi Katsuzo
Published: September 2006

Single domain GaAs layers with satisfactory morphology were grown on (100)-oriented Si substrates by heat treatment of the substrates at above 900°C and subsecquent two-step growth at low temperatures of 450°C or below and by conventional growth temperatures. The grown GaAs layers showed a high mobility of 5200 cm2V-1s-1 at room temperature with a carrier density of 1×1016 cm-3.
Maskless Dry Etching of Gallium Arsenide with a Submicron Line-Width by Laser Pyrolysis in CCl4 Gas Atmosphere
Authors: Takai Mikio , Tsuchimoto Junichi , Nakai Hiroyuki , Gamo Kenji , Namba Susumu
Published: September 2006

Localized etching of GaAs using Ar ion laser beams focused down to 1.2 µm has been performed in a CCl4 atmosphere to realize a maskless dry etching process with a submicron line-width. It was found that etched line patterns with a line-width down to 0.6 µm could be obtained by laser irradiation with a power of 80 mW in a CCl4 atmosphere at a pressure or 30 Torr. Etching rates ranged from 2.2 to 6.3 µm/s, which were greater by up to 4 orders of magnitude than those of ultraviolet laser photolysis.
Highly Sensitive Laser Spectroscopic Method for Measurement of Collisional Relaxation Parameters of Molecules
Authors: Kajita Masatoshi , Kuga Takahiro , Kuze Hiroaki , Matsushima Fusakazu , Shimizu Tadao
Published: September 2006

An intracavity time-resolved spectroscopic method has been developed for studies of collisional relaxation mechanisms associated with very weak infrared transitions. The Stark pulse applied on absorptive molecules modulates the loss in the laser cavity. Transient behaviors of the laser output provide information on the molecular relaxation. The experiment is carried out on frequency coincidences between the ν7
rR(6, 6) transition of CH3CN and the 9 µm R(22) CO2 laser line and between the ν6
pR(10, 8) transition of CH3Cl and the 10 µm R(20) CO2 laser line. The relaxation rate constant is determined.
p-Channel AlGaAs/GaAs Heterostructure FETs Employing Two-Dimensional Hole Gas
Authors: Hirano Makoto , Oe Kunishige , Yanagawa Fumihiko
Published: September 2006

P-channel AlGaAs/GaAs heterostructure FETs (p-HFETs) employing two-dimensional hole gas (2DHG) were fabricated and their characteristics were measured at 300 and 77 K. The achieved extrinsic transconductances were respectively 16 mS·mm-1 and 46 mS·mm-1 with a gate length of 1 µm. Calculations indicate that transconductances of more than 100 mS·mm-1 at 300 K and more than 200 mS·mm-1 at 77 K should be achievable in p-HFET devices. The above results demonstrate the possibility of employing p-HFETs for complementary logic, workable even at room temperature.
Theory of Charge Transfer in Amorphous-Silicon Charge-Coupled Devices
Authors: Takeuchi Yuusuke , Uchida Yasutaka , Matsumura Masakiyo
Published: September 2006

Charge transfer in amorphous-silicon charge-coupled devices is analyzed, taking the density distribution of residual electrons perpendicular to the insulator/amorphous-silicon interface into account. The high transfer inefficiency obtained experimentally is explained by this thickness effect. When the amorphous-silicon layer is as thin as 10 nm, the transfer inefficiency is predicated to approach 10-4 at clock frequencies of more than 10 kHz.
High-Speed Low-Power Ring Oscillator Using Inverted-Structure Modulation-Doped GaAs/n-AlGaAs Field-Effect Transistors
Authors: Kinoshita Haruhisa , Nishi Seiji , Akiyama Masahiro , Kaminishi Katsuzo
Published: September 2006

Modulation-doped GaAs/n-AlGaAs field-effect transistors with inverted structures, i.e. undoped GaAs on top of n-AlGas, have been successfully used in E/D-type DCFL ring oscillators. An inverted heterojunction structure grown by MBE showed a high electron mobility of about 20,000–92,000 cm2/(Vs) at 77 K. In the enhancement mode (E-mode) FETs with 1.2 µm gate length, a maximum transconductance of 250 mS/mm and a K-value of 7.3 mA/V2 were achieved at 77 K. Low ohmic contact resistances of 0.1–0.4 Ωmm with a mean value of 0.2 Ωmm were obtained in a 2 inch-diameter wafer at 300 K and 77 K. A 21-stage ring oscillator showed a minimum gate delay of 26.3 ps with a power dissipation of 234 µW/gate at 77 K.
Background Generation at Input Screens of X-Ray Image Intensifiers
Authors: Tsuda Motohisa , Kimura Yutaro
Published: September 2006

The background luminance due to the input screen of an X-ray image intensifier (I.I.) was investigated quantitatively as a function of several parameters by means of contrast ratios.
The contrast ratio of the input screen increases as the curvature of the screen, the transparency of the photoelectric surface or the reflectance at the inner surface of the electrodes decreases.
By comparing measured contrast ratios of actual I. I.s, the contribution of the background luminance at the input screen to that of the I.I. was estimated.
The contrast ratio of the input screen ranges from 40 to 200, while those of the ordinary I.I. and the ordinary output screen are 14 and 26 respectively.
Formation of Polycrystalline CdSe Films by Molecular-Beam Deposition
Authors: Hyugaji Masahiko , Miura Tadao
Published: September 2006

Polycrystalline CdSe films were formed by molecular-beam deposition (MBD) on glass substrates under an ultra-high vacuum, and the structural and electrical characteristics of the films were investigated. The surfaces of the films became less smooth as the substrate temperature increased. The crystal structure was of the würtzite type with a preferential orientation of the (0001) planes parallel to the substrate. TEM investigation showed that the average grain size increases from a few hundred Å to a few micrometers as the substrate temperature is raised from R. T. to 300°C. These values are about ten times as large as any previously reported. This good crystallinity of CdSe films formed by MBD is attributed to the slow growth under ultra-high vacuum conditions. The resistivity had a maximum value of about 1×105 Ω·cm at a substrate temperature of 200°C.
Electric-Field-Enhanced Extrinsic Photoluminescence in AlGaAs-GaAs Single-Quantum Wells
Authors: Horikoshi Yoshiji , Fischer Albrecht , Ploog Klaus
Published: September 2006

The low-temperature photoluminescence of a 5 nm Al
x
Ga1-x
As-GaAs single-quantum well in an electric field normal to the quantum-well plane has been investigated. When only the GaAs quantum well is photoexcited, the luminescence exhibits a low-energy shift under both reverse and forward bias. This low-energy shift is accompanied by a line broadening. The experimental results are explained by two competing radiative recombination processes, i.e. intrinsic free-exciton recombination and recombination between n=1 electrons and neutral acceptor-like centers near the heterojunction interfeces. The application of an electric field displaces the hole distribution in the quentum well more strongly than the electron distribution and thus enhances the recombination process, including the acceptor-like centers near the hetero-junction interfaces.
Carrier Mobility of Pyrolyzed Polyimide Films
Authors: Hara Takeo , Tsutsui Tetsuo , Saito Shogo
Published: September 2006

The carrier mobility of pyrolyzed polyimide films was estimated by the time-of-flight technique. The carrier mobility could be estimated for the polyimides pyrolyzed between 480 and 530°C, which possessed conductivities between 10-12 and 10-8 S cm-1 and mobilities ranging from 10-7 to 10-3 cm2V-1s-1. The number of carriers connected with charge transport remained unchanged even when the pyrolysis temperature was varied from 490 to 530°C, as the conductivity was proportional to the mobility. In polymides pyrolyzed at lower temperatures, below 490°C, a deviation from the close relation between the mobility and the conductivity was observed. These results suggest that the carrier density increases at the initial stage of the pyrolysis, and then the increase of the mobility becomes predominant as the pyrolysis progresses.
High-Field Conduction and Electrical Breakdown of Polyethylene at High Temperatures
Authors: Hikita Masayuki , Tajima Seiji , Kanno Ippei , Ishino Iwao , Sawa Goro , Ieda Masayuki
Published: September 2006

The mechanism of the breakdown occurring when a dc ramp voltage is applied to low-density polyethylene (LDPE) and silane cross-linked PE at high temperatures is discussed, using experimental results on the Young's modulus Y, high-field conduction and pre-breakdown currents. The electric strength F
B of PE was found to be a function of Y, irrespective of cross-linking. It was also found that, over a wide temperature range, a sharp pre-breakdown current increase could not be detected till a time before breakdown of 100 ns, the resolution limit of the measuring system. The results showed that, under the present experimental conditions, thermal breakdown is not applicable to PE over a wide temperature range and that breakdown is initiated by an electronic process which has a very short time lag to breakdown of the order of some tens of ns or less.
Dielectric and Magnetic Properties of Pb(Fe1/2Ta1/2)O3
Authors: Nomura Shōichiro , Takabayashi Hitoshi , Nakagawa Takehiko
Published: September 2006

Single crystals of Pb(Fe1/2Ta1/2)O3 were grown from ternary melts with excess PbO. The crystals, having cubic perovskite structure at room temperature, undergo a ferroelectric phase transition at about 243°K, changing to rhombohedral structure. The dielectric constant passes through a maximum of nearly 9500 at 1 KHz. The spontaneous polarization along [100] direction is ca 28 µC/cm2 at liquid nitrogen temperature. A magnetic anomaly at about 180°K is related to the onset of antiferromgnetic ordering.
Accurate Real-Time Feedback of Surface EMG During fMRI
Authors: Ganesh G. , Franklin D. W. , Gassert R. , Imamizu H. , Kawato M.
Published: September 2006

Real-time acquisition of EMG during functional MRI (fMRI) provides a novel method of controlling motor experiments in the scanner using feedback of EMG. Because of the redundancy in the human muscle system, this is not possible from recordings of joint torque and kinematics alone, because these provide no information about individual muscle activation. This is particularly critical during brain imaging because brain activations are not only related to joint torques and kinematics but are also related to individual muscle activation. However, EMG collected during imaging is corrupted by large artifacts induced by the varying magnetic fields and radio frequency (RF) pulses in the scanner. Methods proposed in literature for artifact removal are complex, computationally expensive, and difficult to implement for real-time noise removal. We describe an acquisition system and algorithm that enables real-time acquisition for the first time. The algorithm removes particular frequencies from the EMG spectrum in which the noise is concentrated. Although this decreases the power content of the EMG, this method provides excellent estimates of EMG with good resolution. Comparisons show that the cleaned EMG obtained with the algorithm is, like actual EMG, very well correlated with joint torque and can thus be used for real-time visual feedback during functional studies.
On transformation semigroups which are ℬ𝒬‐semigroups
Authors: Nenthein S. , Kemprasit Y.
Published: September 2006

A semigroup whose bi‐ideals and quasi‐ideals coincide is called a
ℬ𝒬‐semigroup. The full transformation semigroup on a set
X and the semigroup of all linear transformations of a vector
space V over a field F into itself are denoted, respectively, by T(X) and LF(V). It is known that every regular semigroup is a
ℬ𝒬‐semigroup. Then both T(X) and LF(V) are ℬ𝒬‐semigroups.
In 1966, Magill introduced and studied the subsemigroup of T(X), where ∅≠Y⊆X and . If W is a subspace of V, the subsemigroup of LF(V) will be defined analogously. In this paper, it is shown that is a ℬ𝒬‐semigroup if and only if Y = X, |Y| = 1, or |X| ≤ 3, and is a ℬ𝒬‐semigroup if and only if (i) W = V, (ii) W = {0}, or (iii) F = ℤ2, dimFV = 2, and dimFW = 1 .
A class of principal ideal rings arising from the converse of theChinese remainder theorem
Authors: Dobbs David E.
Published: September 2006

Let R be a (nonzero commutative unital) ring. If I and J are ideals of R such that R/I ⊕ R/J is a cyclic R‐module,
then I + J = R. The rings R such that R/I ⊕ R/J is a cyclic
R‐module for all distinct nonzero proper ideals I and J of R are the following three types of principal ideal rings:
fields, rings isomorphic to K × L for the fields K and L, and special principal ideal rings (R, M) such that M2 = 0.
A new proof of a lemma by Phelps
Authors: Cardwell Antonia E.
Published: September 2006

We give a different proof of a lemma by Phelps (1960) which
asserts, roughly speaking, that if two norm‐one functionals f and g have their hyperplanes f−1(0) and g−1(0) sufficiently close together, then either ‖f − g‖ or ‖f + g‖ must be small. We also extend this result to a complex
Banach space.
Time‐dependent vector stabilization
Authors: Nikitin Sergey
Published: September 2006

The paper presents necessary and sufficient conditions for a
single input system defined by a time‐dependent vector to be
stabilized by a linear feedback. The paper employs a new technique
based on averaging along a moving time interval.
On some exponential means. Part II
Authors: Sándor József , Toader Gheorghe
Published: September 2006

We prove some new inequalities involving an exponential mean, its complementary, and some means derived from known means by applying the exp‐log method.
In vitro Drug Sensitivity Predicts Response and Survival after Individualized Sensitivity-Directed Chemotherapy in Metastatic Melanoma: A Multicenter Phase II Trial of the Dermatologic Cooperative Oncology Group
Authors: Ugurel Selma , Schadendorf Dirk , Pföhler Claudia , Neuber Karsten , Thoelke Adina , Ulrich Jens , Hauschild Axel , Spieth Konstanze , Kaatz Martin , Rittgen Werner , Delorme Stefan , Tilgen Wolfgang , Reinhold Uwe
Published: September 2006

Purpose: In vitro sensitivity assays are promising tools to predict the individual outcome of different chemotherapy regimens. However, a direct association between in vitro and in vivo chemosensitivity has to be shown by clinical studies. This multicenter phase II trial was aimed to investigate the efficacy of a sensitivity-directed, first-line chemotherapy in metastasized melanoma patients, and to prove an association between in vitro sensitivity and therapy outcome.

Patients and Methods: The primary study end point was objective response; secondary end points were safety, overall survival, and progression-free survival. Viable tumor cells obtained from metastatic lesions were tested for chemosensitivity to seven single drugs and five drug combinations using an ATP-based luminescence viability assay.

Results: Out of 82 recruited patients (intention-to-treat), 57 received assay-directed chemotherapy and 53 were evaluable for all study end points (per protocol). The drug combinations used were gemcitabine + treosulfan, paclitaxel + cisplatin, paclitaxel + doxorubicin, and gemcitabine + cisplatin. The per protocol population could be divided into 22 (42%) chemosensitive and 31 (58%) chemoresistant patients by an arbitrary chemosensitivity index. Objective response was 36.4% in chemosensitive patients compared with 16.1% in chemoresistant patients (P = 0.114); progression arrest (complete response + partial response + stable disease) was 59.1% versus 22.6% (P = 0.01). Chemosensitive patients showed an increased overall survival of 14.6 months compared with 7.4 months in chemoresistant patients (P = 0.041).

Conclusion: In vitro chemosensitivity testing may be worthy of further exploration to see if it could be a useful tool to predict the outcome of melanoma patients treated with a sensitivity-directed chemotherapy. Therefore, these preliminary results will be evaluated by a planned phase III trial using a randomized, standard-regimen controlled setting.
Mouse Models of Brain Tumors and Their Applications in Preclinical Trials
Authors: Fomchenko Elena I. , Holland Eric C.
Published: September 2006

Primary brain tumors, including gliomas and medulloblastomas, often represent the most devastating and difficult-to-treat tumors, and are thought to arise from glial cells and/or their precursors or the external granule cell layer, respectively. The majority of genetic alterations characteristic of the human brain tumors are thought to occur in genes encoding proteins involved in signal transduction or cell cycle regulation. Accurate recapitulation of these genetic alterations using genetically engineered mouse models allows for in vivo modeling of brain tumors with similar histopathology, etiology, and biology. These mouse models, in turn, increase our understanding of brain tumor initiation, formation, progression, and metastasis, providing an experimental system to discover novel therapeutic targets and test various therapeutic agents.
The Thalidomide Analogue, CC-4047, Induces Apoptosis Signaling and Growth Arrest in Childhood Acute Lymphoblastic Leukemia Cells In vitro and In vivo
Authors: Shalapour Shabnam , Zelmer Andrea , Pfau Madlen , Moderegger Eva , Costa-Blechschmidt Cristiane , van Landeghem Frank K.H. , Taube Tillmann , Fichtner Iduna , Bührer Christoph , Henze Günter , Seeger Karl , Wellmann Sven
Published: September 2006

Purpose: Thalidomide and its analogues have shown promise in the treatment of multiple myeloma but their therapeutic potential has not been evaluated in models of acute lymphoblastic leukemia (ALL).

Experimental Design: We assessed the effects of the thalidomide analogue, CC-4047, on the growth and apoptosis signaling of human B cell precursor (BCP) ALL cell lines and freshly obtained childhood BCP-ALL cells grown with or without stromal cells. In addition, we studied the effects of CC-4047 on the progression and dissemination of xenotransplanted human BCP-ALL cells in nonobese diabetic/severe combined immunodeficiency mice.

Results: CC-4047 reduced the proliferation of human BCP-ALL cell lines in vitro. In contrast with the antileukemic effect of cytarabin, this was more pronounced when cell lines or freshly obtained childhood BCP-ALL cells were cocultured with stromal cells. CC-4047 induced the cleavage of caspase-3, caspase-9, and poly(ADP-ribose) polymerase in stroma-cocultured BCP-ALL cells. The inhibition of tumor growth, caspase-3 cleavage, and reduced microvessel density was observed in nonobese diabetic/severe combined immunodeficiency mice inoculated s.c. with childhood BCP-ALL cells upon CC-4047 treatment. After i.v. BCP-ALL xenotransplantation, CC-4047 reduced splenic dissemination.

Conclusions: The thalidomide analogue, CC-4047, displays profound cytostatic effects on stroma-supported human ALL cells both in vitro and in vivo.