bluuebunny/crossref_metadata_2025_split huggingface dataset:
High frequency of prostate antigen‐directed T cells in cancer patients compared to healthy age‐matched individuals
Authors: Forsberg Ole , Carlsson Björn , Malmström Per‐Uno , Ullenhag Gustav , Tötterman Thomas H. , Essand Magnus 
Published: September 2008

AbstractBACKGROUNDIn order to obtain a sustained cytotoxic T lymphocyte (CTL) response against cancer cells it is preferable to have CTLs directed against multiple peptide epitopes from numerous tumor‐associated antigens.METHODSWe used a Flow Cytometry‐based interferon (IFN)‐γ secretion assay with peptide‐pulsed C1R‐A2 as antigen‐presenting cells to analyze whether CD8+ T cells directed against any of 24 HLA‐A*0201‐binding peptides from 15 prostate‐associated proteins can be found in the peripheral blood of patients with localized prostate cancer. We also investigated whether multiple prostate antigen‐specific CD8+ T cells can be generated simultaneously, from a naïve T cell repertoire. In that case, dendritic cells (DCs) from peripheral blood of healthy donors were divided in six portions and separately pulsed with six peptides. The peptide‐pulsed DCs were then pooled and used to stimulate autologous T cells. The T cells were re‐stimulated with peptide‐pulsed monocytes.RESULTSWe found prostate antigen‐restricted CD8+ T cells in the peripheral blood in 48 out of 184 (26.1%) analyzed samples from 25 cancer patients. This is significantly higher than 17 out of 214 analyzed samples (7.9%) from 10 healthy age‐matched male individuals (P = 0.0249). In the cases when antigen‐specific T cells could not be detected, we were able to generate IFN‐γ‐producing CD8+ T cells specific for up to three prostate antigens simultaneously from a naïve T cell repertoire.CONCLUSIONSCD8+ T cells directed against prostate antigen peptides can be found in, or generated from, peripheral blood. This indicates that such T cells could be expanded ex vivo for adoptive transfer to prostate cancer patients. Prostate 69: 70–81, 2009. © 2008 Wiley–Liss, Inc.
The study of ESD induced defects in smart power ESD protection circuits using low frequency noise measurements
Authors: Hadzi‐Vukovic J. , Jevtic M. , Glavanovics M. , Rothleitner H. 
Published: September 2008

AbstractTo investigate the reliability of ESD protection in smart power integrated circuits the ESD experiments are performed and degradation is analyzed by low frequency noise measurements. Combining the noise results with further failure analysis analytical methods we have examined a location and the nature of defects. Special attention was dedicated to analysis of latent defects. The possibility to apply noise as reliability indicator for repetitive testing and for use in high volume production are also discussed. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Low energy loss rf circuits on nanostructured porous silicon layers
Authors: Porcher A. , Remaki B. , Malhaire C. , Barbier D. 
Published: September 2008

AbstractWe present a work dealing with the study of thick porous silicon (PS) as insulating substrate for radio frequency (rf) circuits. Planar LC resonant circuits of 2 mm x 2 mm were designed on 100 µm thick PS layers for uses in 10 MHz to 1 GHz frequency range. The influence of PS electrical conductivity on the energy loss is determined using an original method based on experimental data combined with numerical simulations. We have clearly shown the increase of PS conductivity with the frequency due to hopping transport mechanisms in disordered materials. The contribution of the porous substrate to the energy loss is dominant for conductivities higher than 10–3 S/cm. Finally, the insertion of a SiO2 layer between an oxidized porous substrate and the integrated micro‐coil is suggested to optimize the quality factor of integrated rf resonnant circuits. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Temperature dependent EXAFS of InN
Authors: Katsikini M. , Pinakidou F. , Paloura E. C. , Komninou Ph. , Georgakilas A. , Welter E. 
Published: September 2008

AbstractThe effect of temperature on the bonding environment of indium in an InN epilayer is studied using X‐ray absorption fine structure (EXAFS) spectroscopy. Shell‐by‐shell fitting of the EXAFS spectra reveals that, in the temperature range 80‐245 K, the change in the nearest neighbour distances is smaller than the uncertainty of the measurement. The Debye–Waller factor of the second neighbouring shell (In–In pair) shows strong temperature dependence. Fitting using the Einstein model yields an Einstein temperature equal to 193 K ± 5%. An alternative way of extracting information on the vibrational properties of the lattice is the simulation using the equation of motion method for the determination of the Debye–Waller factors. The used values of 120 N/m and 50 N/m of the force constants for In–N and In–In bond stretching, respectively, simulate satisfactory the spectra measured at five different temperatures in the range 80– 245 K. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Novel effects in finite‐length silicon nanowires
Authors: Zdetsis A. D. , Koukaras E. N. , Garoufalis C. S. 
Published: September 2008

AbstractBy considering silicon nanowires in real space, we have shown by ab initio theoretical calculations that unstable nanowires bend under relaxation. These nanowires usually incorporate in their surface silicon dihydrides parallel to the nanowires axis. On the other hand, nanowires without such parallel dihydrides remain straight and are characterized by increased stability or “magicity”. Reconstructed nanowires have analogous properties but they are characterized by much higher stability. This bending of the nanowires cannot be accounted for by the usual k‐space models which use a one‐dimensional periodic arrangement of the simulation cell. Our theoretical models are based on STM images and schematic views from recent experimental results [Science 229, 1874, (2003)]. Our results are in full accord with these experimental data and interpretations. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Deterministic simulation of transport in MOSFETs by coupling Wigner, Poisson and Schrödinger equations
Authors: Kefi‐Ferhane J. , Poncet A. 
Published: September 2008

AbstractIn this paper, we present a new simulation approach for quantum transport in short and thin MOSFET channels which is based on a deterministic resolution of 1D Wigner Transport Equation and its couplings with 2D Poisson and 1D Schrödinger equations. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Microstructure and defect investigations of the layered manganites La2–2xCa1+2xMn2O7 (x = 0.6, 0.8 and 0.9) by HREM
Authors: Wang Yumei , Yu Richeng 
Published: September 2008

AbstractThe microstructure and defects of the n = 2 Ruddlesden–Popper manganites La2–2x Ca1+2x Mn2O7 (x = 0.6, 0.8 and 0.9) were investigated by electron diffraction and high‐resolution transmission electron microscopy. Besides the predominant n = 2 layered structure in the examined compounds, intergrowths with different number of the perovskite‐like layers were observed. Intergrowth of n = 1 (K2NiF4‐type) was observed only in x = 0.9 sample. Intergrowths with n ≥ 5, essential perovskite microdomains or inclusions, were seen in the x = 0.8 and 0.6 samples. The type of defects in x = 0.8 sample is much richer than that in x = 0.6 and 0.9 samples and two rare types were observed and analyzed. Some of edge dislocations in the x = 0.6 specimen were presented. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Structural and optical studies of Eu3+ ions in alkali borate glasses
Authors: Marimuthu K. , Surendra Babu S. , Muralidharan G. , Arumugam S. , Jayasankar C. K. 
Published: September 2008

AbstractEuropium‐doped borate‐based glasses (Eu3+:MBE (M = Na, K and Na + K)) have been prepared by a melt quenching technique and characterized optically. FTIR spectra and XRD patterns were used to analyze the glass structure. The spectroscopic properties such as optical absorption and photoluminescence spectra and decay time measurements for the 5D0 level of Eu3+ ions were obtained. A strong red fluorescence is observed from the 5D0 level of Eu3+ ions in these glasses. Judd–Ofelt (JO) parameters have been evaluated from the luminescence intensity ratios of 5D0 → 7FJ (J = 2 and 4) to 5D0 → 7F1 transitions. These parameters have been used to derive radiative properties such as transition probabilities, branching ratios, radiative lifetimes and peak stimulated emission cross sections for the 5D0 → 7FJ transitions. The relative luminescence intensity ratio (R) of 5D0 → 7F2 to 5D0 → 7F1 transitions has been evaluated to estimate the local site symmetry around the Eu3+ ions. Relatively higher values of R and the JO parameter Ω2 for the Eu3+:MBE glasses suggest a lower symmetry for Eu3+ ions and a higher Eu–O covalence. Decay curves of the 5D0 level of Eu3+ ions have been measured by monitoring the 5D0 → 7FJ transition (at around 612 nm) at room temperature. The experimental lifetime of the 5D0 level in these glasses is found to be lower than Eu3+‐doped phosphate glasses and comparable to or higher than Eu3+‐doped niobium phosphate or tellurite glasses. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Theoretical investigations of spin‐Hamiltonian parameters for Ru3+ ions in rutile (TiO2) crystal
Authors: He Lv , Zheng Wen‐Chen 
Published: September 2008

AbstractIn this paper, we present two diagonalization of energy matrix methods (DEM‐I and DEM‐II) to calculate the spin‐Hamiltonian (SH) parameters of the low‐spin d5 configuration (with the ground state 2T2 and spin S = 1/2) in rhombic symmetry. The x ‐ and y‐axes in which SH parameters are expressed are taken along the bisectors of the angles between metal‐ligand bonds in crystals e.g., rutile‐type crystals. In DEM‐I, the Hamiltonian related to energy matrix within the 2T2 term does not contain the Zeeman interaction and hyperfine interaction, whereas in DEM‐II, it does. Based on the two methods, the SH parameters (g factors gi, hyperfine structure constants 99Ai and 101Ai, where i = x, y, z) of Ru3+ (4d5) ions in TiO2 are calculated. The results from both methods coincide and are also in reasonable agreement with the experimental values. So, both methods are reliable for prediction of SH parameters for the low‐spin d5 ions in crystals. The signs of hyperfine structure constants Ai are also suggested from the calculations. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Theoretical description of energy spectra of nanostructures assuming specular reflection of electron from the structure boundary
Authors: Vieira V. R. , Vorobiev Y. V. , Horley P. P. , Gorley P. M. 
Published: September 2008

AbstractThe quantum mechanical description of an electron in a nanostructure (like quantum dot, quantum well, organic dye molecule, etc.) strongly depends upon the boundary conditions applied. The classic free electron molecular orbital approximation uses the impenetrable walls conditions which could only be applied to the structures of the simplest geometry, and do not reflect the real character of the interaction of an electron with the structure's boundary, which in many cases is a specular (mirror‐like) reflection. We attempted to introduce the “mirror ” boundary conditions in the treatment of a particle (electron) confined in quantum wells (nanostructures) of several different geometries, assuming that for any point inside the well we could find the corresponding points reflected by all the structure “walls”, and write the boundary conditions as equivalency of the Ψ‐functions in real and reflected points. We show that for structures of sufficiently high symmetry these conditions are equivalent to the periodic ones considering that the quantum well studied together with its reflections form a periodic structure. The new “mirror” boundary conditions could be applied to a variety of cases (nanostructure's geometry), showing a reasonable agreement between the theory and the experiment without any adjustable parameters. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
FEMO modelling of optical properties of natural biopolymers chitin and chitosan
Authors: Luna‐Bárcenas G. , Gonzalez‐Campos B. , Elizalde‐Peña E. A. , Vivaldo‐Lima E. , Louvier‐Hernández J. F. , Vorobiev Y. V. , González‐Hernández J. 
Published: September 2008

AbstractChitin and its derivative chitosan are widely used in the food, cosmetic, agricultural and biomedical industries because of their physicochemical and biocompatible properties. In this work, we studied thin films of both materials prepared by a solvent‐cast method. The optical properties were investigated in the UV‐VIS and infrared (IR) spectral regions; both biopolymers exhibit similar absorption bands characterized by two regions at 250–500 nm and at 850–1300 nm. Chitin and chitosan have practically the same parameters of a crystalline structure. We assume that these features (similarity of the structure and of the optical properties) are not just the coincidence but reflect the essential relation between the crystalline structure symmetry and the electronic transitions. The later was modeled on the basis of the quantum mechanical Free Electron Molecular Orbital approximation, using the new type, mirror‐like boundary conditions. The calculations made on the basis of the known parameters of crystalline structure give reasonable agreement with the experimental spectra without any adjustable parameters. The difference between the optical properties of the two materials in the IR region reflects the difference in their molecular structure and composition. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Nanoporous oxides of refractory metals: fabrication and properties
Authors: Lazarouk S. K. , Sasinovich D. A. , Borisenko V. E. 
Published: September 2008

AbstractA new approach to fabrication of nanoporous oxides of refractory metals is presented. It is based on the magnetron co‐sputtering of aluminum and refractory metal (titanium, niobium or tungsten) followed by porous electrochemical anodization of the composite film and selective etching of alumina. The nanoporous oxide films with a thickness up to 5 µm were fabricated and studied. The porosity of the oxide films characterized by the surface area of 230 – 460 m2/cm3can betuned by the aluminum content in the as‐deposited composite films. The pore diameters are found to be varied in nanometer and subnanometer ranges. The parameters of porous titania within porous alumina matrix for different titanium concentrations are presented. The fabricated porous composite oxide films are characterized by the refractive index in the range from 1.45 to 1.77. The dielectric permeability for these films is found to be varied from 6.7 to 24. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Influence of Ga on the growth of NiSi2 on Si
Authors: Mogilatenko A. , Allenstein F. , Schubert M. A. , Falke M. , Beddies G. , Hinneberg H.‐J. , Neumann W. 
Published: September 2008

AbstractThe study reports on the structure of thin ternary NiGaxSi2–x silicide layers grown on Si(001) by Ni/Ga codeposition at room temperature followed by subsequent annealing. The influence of both the Ga content and the annealing temperature on the phase formation and orientation of the layers was investigated for the first time. Addition of Ga leads to a decrease of the disilicide formation temperature down to less than 500 °C. Island formation is observed for the Ga content of 0.17 after annealing above 900 °C. The NiSi2‐xGax islands grow with a NiSi2–xGax(110) ‖ Si(001) texture. In contrast, closed epitaxial NiSi2–xGax layers of A‐type are obtained for the Ga content of 0.28 after annealing at 900 °C. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Computer‐assisted analysis of TEM diffraction contrast images of (In,Ga)N/GaN nanostructures
Authors: Manolaki P. , Häusler I. , Kirmse H. , Mogilatenko A. , Neumann W. , Smałc‐Koziorowska J. , Skierbiszewski C. 
Published: September 2008

AbstractIII‐nitride semiconductor nanostructures are subject of intense studies with respect to their optoelectronic, structural and chemical properties. Important parameters for the wavelength of the emitted light are the chemical composition and the dimensionality of the nanostructures. Transmission electron microscopy is used to determine these characteristics at a nanometer scale. In this work, the information provided by diffraction contrast images of (In,Ga)N/GaN quantum wells (QWs) is studied. Experimental dark‐field images alternatively using the 0001 and the 0002 reflection show a different contrast regime. In order to understand the contrast, one has to calculate the intensity Ig of the individual diffracted beam g. The intensity of the 0002 beam is a function of the sum of the atomic scattering amplitudes of the group III and the group V element. Consequently, the 0002 reflection is strain sensitive. According to the kinematical theory the 0001 reflection is forbidden. However, it is excited in the experiment. Therefore, dynamical effects have to be taken into account. The corresponding intensity is calculated by the Howie‐Whelan equations. It turns out that the intensity of the 0001 beam strongly depends on the In content of (In,Ga)N. A good agreement of intensity profiles of 0001 dark‐field images compared to the theory is found. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Deposition and electrical characterization of hafnium oxide films on silicon
Authors: Verrelli E. , Tsoukalas D. , Kouvatsos D. 
Published: September 2008

AbstractHafnium oxide dielectric is under intense investigation in recent years as a new high‐k insulator to replace silicon dioxide thus allowing further device scaling in silicon technology. In this work we investigate HfO2 deposited films using RF reactive sputtering technique and we present results on their electrical characterization using MOS capacitors. The HfO2 films have been sputtered on n or p‐type Si substrate from high purity HfO2 target at low deposition rate (0.1 Å/s) monitored by a quartz crystal. After deposition of the insulator aluminum has been evaporated and patterned to form MIS capacitors. In this paper we investigate the effect of deposition parameters and post‐deposition‐annealing on the electrical properties of the HfO2 films. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electron microscopy investigation of extended defects in a‐plane gallium nitride layers grown on r‐plane sapphire by molecular beam epitaxy
Authors: Smalc‐Koziorowska J. , Komninou Ph. , Sahonta S.‐L. , Kioseoglou J. , Tsiakatouras G. , Georgakilas A. 
Published: September 2008

AbstractThe interfacial structure and extended defects in a‐plane (1120)‐oriented GaN layers are investigated using conventional and high resolution transmission electron microscopy (HRTEM). The a‐plane GaN epilayers have been grown by nitrogen rf plasma source molecular beam epitaxy (RFMBE) on r‐plane sapphire substrates, which have been nitrided either at 200 °C or at 800 °C for one hour. A thin interfacial layer of strained AlN, with an average thickness of about 1 nm, was formed during nitridation of the sapphire surface at both temperatures. The extended defects observed in the GaN layers are predominantly threading dislocations and basal stacking faults (BSFs), which originate from the GaN/sapphire interface. The threading dislocation density is slightly reduced in the film nitrided at 800 °C, as is the density of inversion domains, although stacking fault density does not appear to change with nitridation conditions. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Flexible organic light emitting diodes (OLEDs) based on a blue emitting polyfluorene
Authors: Vasilopoulou M. , Palilis L. C. , Botsialas A. , Georgiadou D. G. , Bayiati P. , Vourdas N. , Petrou P. S. , Pistolis G. , Stathopoulos N. A. , Argitis P. 
Published: September 2008

AbstractFlexible OLEDs were demonstrated using a highly efficient blue electroluminescent polyfluorene derivative. The flexible devices were fabricated on indium tin oxide (ITO) coated polyethylene terephthalate (PET) substrates with a sheet resistance of 35 Ω per sq. The emitting layer was poly[9,9‐di‐(2′‐ethylhexyl)fluorenyl‐2,7‐diyl] (PF). A significant improvement of the luminance and device efficiency was achieved by confining the exciton formation zone within PF by two wide band‐gap materials, namely PVK as a hole transport layer (HTL) and an inorganic oxide layer (IOL) as an electron transport and hole blocking layer. In order to achieve full‐color LEDs based on a common host material, we probed the use of suitable dye emitters dispersed in PF at appropriate concentrations. The selection of the emitters is based on their capability to be effective energy transfer acceptors from the blue emitting PF. In particular, energy transfer was demonstrated from blue to green for PF‐doped with the green dye emitter 1‐[4‐(dimethylamino)phenyl]‐6‐phenylhexa‐1,3,5,‐triene (DMA‐DPH), and from blue to red for PF‐doped with the red dye emitter (4‐dimethylamino‐4′‐nitrostilbene) (DANS). This demonstration paves the way for developing highly efficient blue, green and red flexible OLEDs based on a common blue emitting PF host. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Estimation of metallic contact effects on the performance of (SI) GaAs soft X‐ray radiation detectors
Authors: Theonas V. , Konstantinidis G. , Papaioannou G. 
Published: September 2008

AbstractSemi‐insulating (SI) GaAs offers an attractive choice as a room temperature electromagnetic radiation detector, due to the high mean atomic number of the compound, the relatively low radiation ionization energy and high carrier's mobility. Standard detector configuration consists on a metal alloy Ohmic and a rectifying Schottky contact on either side of GaAs substrate. Metallic contacts, upon irradiation, inject fast electrons towards GaAs. These injected electrons provide an excess charge build‐up in the detectors active region. We investigated the contact thickness effect in charge build‐up and the consequent detector photo‐response, upon detectors irradiation by soft X‐ray photons. The secondary electrons induced excess photo‐current was experimentally verified at low bias conditions. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Femtosecond laser‐assisted formation of channels in sapphire using KOH solution
Authors: Juodkazis Saulius , Nishi Yasufumi , Misawa Hiroaki 
Published: September 2008

AbstractWe report on wet etching of photomodified regions in crystalline sapphire using KOH solution. Tightly focused femtosecond laser pulses (150 fs at 800 nm wavelength) were used to create void structures enclosed in an amorphised sapphire shell inside the bulk of a crystalline host. The diameter of the amorphous regions can be controlled by pulse energy and was typically 0.5–1.5 µm. The etching rate depends on the distance between adjacent irradiation spots, pulse energy, concentration of etchant and ultrasonic agitation.magnified imageAmorphised sapphire is etched out in KOH solution.(© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)