bluuebunny/crossref_metadata_2025_split huggingface dataset:
Low energy quasiparticle dispersion of graphite by angle‐resolved photoemission spectroscopy
Authors: Grüneis A. , Pichler T. , Shiozawa H. , Attaccalite C. , Wirtz L. , Molodtsov S. L. , Follath R. , Weber R. , Rubio A. 
Published: October 2007

AbstractThe low energy electron dispersion in graphite is measured by angle‐resolved photoemission spectroscopy. The measured photoemission intensity maxima are compared to a tight‐binding calculation of the electronic band structure. We observe a strong trigonal warping of the equi‐energy contour which is well reproduced by the calculations. Furthermore we clearly show that the concept of Dirac Fermions breaks down for AB stacked graphite. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optical properties of silver nanoparticles
Authors: González A. L. , Noguez Cecilia 
Published: October 2007

AbstractThe optical response of embedded silver nanoparticles in terms of their morphology and dielectric environment is studied. Employing a discrete dipole approximation, the extinction efficiencies are calculated for nanoparticles of different shapes and in diverse ambient conditions. A clear dependence of the number, width and position of the surface plasmon resonances (SPRs) is identified for various nanoparticle shapes. For faceted particles, it is found that as the truncation of sides increases, the main resonance is always blue shifted, the SPRs at smaller wavelength are closer to the dominant mode, so, they overlap, and the width of the main resonance increases. The SPRs vanish as the number of faces increases, or when the symmetry of the NP becomes larger. As the vertices become sharper, the number of resonances increases significantly. By changing the refraction index of the environment, the number of SPRs is not affected, although their width and position are modified, so that, for larger the refraction indeces the resonances are red shifted. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Mechanical and tribological characterization of CNx films deposited by d.c. magnetron sputtering
Authors: Ipaz L. , Yate L. , Polcar T. , Camps E. , Escobar‐Alarcon L. , Zambrano G. , Prieto P. 
Published: October 2007

AbstractCarbon nitride (CNx) thin films were deposited onto silicon and steel substrates at 400 °C from a carbon target by d.c. magnetron sputtering system. The composition, structural, and mechanical properties of deposited films were investigated as a function of argon/nitrogen concentration and sputtering power, by means of Energy Dispersive X‐ray Spectroscopy (EDS), Fourier Transform Infrared Spectroscopy (FTIR), Raman Spectroscopy (RS), and nanoindentation. The EDS and Elastic Forward Analisys Analysis (EFA) showed that the nitrogen concentration in the CNx deposited films varied between 16% and 28% at depending on nitrogen concentrations in argon/nitrogen gas mixture, and deposition power. FTIR analysis indicated the presence of 2266 and 2278 cm–1 stretching peaks associated with CN triple bonds of nitriles and isocyanides, 1640 cm–1 and 1545 cm–1 associated with the C=C and C=N bonds. The thickness of the CNx deposited films varied between 0.4 and 0.8 µm at different sputtering powers. The hardness and Young's modulus were investigated by depth sensing nanoindentation method. The obtained hardness and Young's modulus increased from 4 to 17 GPa, and from 50 to 170 GPa, respectively; when the nitrogen content in the deposited films diminished between 28 and 12%. On the other hand, the friction and wear tests were done using a pin‐on‐disc tribometer. The friction tests showed values of 0.05 and 0.4 in dry air and humid atmosphere; respectively. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Nanostructured multilayers of TiN/ZrN obtained by magnetron sputtering
Authors: Caicedo A. J. C. , Bejarano G. G. , Gomez M. E. , Prieto P. , Cortéz C. , Muñoz J. 
Published: October 2007

AbstractIn order to find an industrial application for thin films of TiN and ZrN monolayers, as well as TiN/ZrN multilayers were deposited onto silicon (100) and AISI 5160 steel substrates by r.f. (13.56 MHz) multi‐target magnetron sputtering from high‐purity (99.5%) Ti and (99.5%) Zr targets in an Ar (93%)/N2 (7%) gas mixture. For their deposition, we applied a substrate bias voltage of ‐100 V and a target power of 350 W. The films were deposited at a pressure of 6x10–3 mbar and a temperature of 250 °C. The structure, composition, morphology, and topography were characterized by, XRD, FTIR, SEM, AFM, and optical microscopy. Mechanical properties like hardness and elastic modulus were determined by Nanoindentation. Hardness and elastic modulus of the films increased proportionally to the number of bilayers. Finally, cutting tools were coated with 1, 2, 3, 4, 5, 6, 7, and 8 bilayers of TiN/ZrN. Cutting tests on paper blades were conducted. Increased cut quality performance was observed for cutting tools coated with 8 bilayers, as compared to uncoated tools. This work opens the possibility to use coated AISI 5160 as cutting tools for the paper industry, reducing the import of expensive high‐quality tool steel. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Incorporation of Li in MoO3 thin films grown by evaporation with a CO2 laser
Authors: Diaz D. , Pardo A. P. , Torres J. , Alfonso J. E. , Moreno L. C. 
Published: October 2007

AbstractThis work describes the lithium incorporation process in thin films of MoO3 prepared by evaporation with a laser of CO2, working in continuous wave mode. Targets prepared from mixtures of MoO3 (99.97%) and Li2CO3 (99.98%) in powder were used in the growth of the films. The targets had Li concentrations of 1%, 2% and 5% (lithium ions/total cations). The samples were characterized through X‐rays diffraction, (XRD) and transmittance in the visible spectrum. The XRD spectra show an evolution in the growth of the films, beginning by an amorphous phase for samples with temperatures lower than 200 °C. From this temperature on a mixture of the α and β phases of LiMoO3 and Li2MoO4 appears, which grow along planes (100), (111) for LiMoO3 and (012) for Li2MoO4. The transmittance spectra showed a shift of the material's energy gap towards long wavelengths as the lithium concentration increases in the sample. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effects of the confining interaction on mesoscopic superconducting cylinders
Authors: Pasaje A. , Calero J. M. , Granada J. C. , Silva E. Z. da 
Published: October 2007

AbstractThe most important feature of a mesoscopic superconductor is that its shape and size have an important effect on the interplay of the magnetic field and superconducting condensate. Usually this effect is investigated via the Ginzburg‐Landau (GL) equations, solved together with the conventional boundary condition. This condition implies that the normal component of the superconducting current is equal to zero. However, the approach based on the GL functional for the free energy does not include the contribution acquired by the cooper pairs due to the confining interaction. In this work we use a generalized GL theory proposed by Shanenko and Ivanov, including the confining interaction, in order to study the way the terms arising from the confining potential affect the critical behavior in mesoscopic superconducting samples with cylindrical symmetry without an applied magnetic field. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
New polymer electrolyte based on PVAL‐LiOH‐Al2O3‐H2O
Authors: Fernández M. E. , Diosa J. E. , Vargas R. A. , de los. S. Guerra J. , Villaquiran C. F. , Garcia D. , Eiras J. A. 
Published: October 2007

AbstractIn this work we report the preparation of membranes based on poly (vinyl alcohol) (PVAL), lithium hydroxide, alumina, and water with different alumina concentrations. The samples were characterized by impedance spectroscopy, differential scanning calorimetry (DSC), thermogravimetry, and x‐ray diffraction. The DSC thermograms show three anomalies after the first thermal treatment, the first one as a downward jump at around 20 °C, associated to the glass transition of the polymer, the second one as an endothermic peak around 210 °C associated to the polymer melting point, and the third one as an endothermic peak around 235 °C associated to the decomposition process. The results show that the glass transition temperature is strongly sensitive to the alumina content. Impedance results show a dielectric relaxation that disappears with increasing alumina concentration. The X‐ray diffraction shows that the amorphous part of the composite increases as the alumina concentration increases, indicating an approximation effect of the dispersed ceramic nanoparticles in the polymer matrix. These results can be interpreted by considering the Hodge et al. criterion, which establishes a correlation between the height of this peak an the degree of crystallinity of PVAL. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Interplay of the Rashba and Dresselhaus spin‐orbit coupling in the optical spin susceptibility of 2D electron systems
Authors: López‐Bastidas Catalina , Maytorena Jesús A. , Mireles Francisco 
Published: October 2007

AbstractWe present calculations of the frequency‐dependent spin susceptibility tensor of a two‐dimensional electron gas with competing Rashba and Dresselhaus spin‐orbit interaction. It is shown that the interplay between both types of spin‐orbit coupling gives rise to an anisotropic spectral behavior of the spin density response function which is significantly different from that of vanishing Rashba or Dresselhaus case. Strong resonances are developed in the spin susceptibility as a consequence of the angular anisotropy of the energy spin‐splitting. This characteristic optical modulable response may be useful to experimentally probe spin accumulation and spin density currents in such systems. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Preface: phys. stat. sol. (c) 4/11
Authors: Prieto Pedro , Ulloa Sergio 
Published: October 2007

AbstractThe Inter American Materials Cooperation (CIAM) Workshop “Trends on Novel Materials” provided a setting for interdisciplinary scientific exchange to gather knowledge on new tendencies on materials research. The Workshop gathered a number of the region's top scientists to reveal the most up‐to‐date development and applications of novel materials. It was an appropriate venue for science and engineering students and researchers to develop working relationships to broaden research activities. The event's poster sessions offered an opportunity to interact with young researchers who shared their investigative experiences.Materials research and their processes will greatly improve our quality of life through efficient and environmentally friendly energy production systems. Materials research will bring about great and reliable changes in IT systems, transportation infrastructure, industrial tools, communications, better health care options, and numerous areas in science and technology. Materials research practically encompasses the whole spectrum of scientific and technological knowledge; thus, all initiatives in this direction will translate into increased progress for the benefit of our fragile earth. Our work will, undoubtedly, yield positive socio‐economic impact.We wish to express our most sincere gratitude to our sponsors, and acknowledge that without their generous support these avenues of exchange would not be possible. The National Science Foundation (NSF), which has always promoted and supported network initiatives in materials science; the Colombian Science and Technology agency (COLCIENCIAS) as part of the Inter American Materials Cooperation (CIAM) effort, the Excellence Center for Novel Materials (CENM), and Universidad del Valle were all instrumental in furthering this workshop to aid in strengthening the region's scientific community.The Trends on Novel Materials workshop urged us to think, innovate, and apply the knowledge we have gathered and shared through such noteworthy scientific.
Auxiliary functions for molecular integrals with Slater‐type orbitals. II. Gauss transform methods
Authors: Ema I. , López R. , Fernández J. J. , Ramírez G. , Rico J. F. 
Published: October 2007

AbstractThe Gauss transform of Slater‐type orbitals is used to express several types of molecular integrals involving these functions in terms of simple auxiliary functions. After reviewing this transform and the way it can be combined with the shift operator technique, a master formula for overlap integrals is derived and used to obtain multipolar moments associated to fragments of two‐center distributions and overlaps of derivatives of Slater functions. Moreover, it is proved that integrals involving two‐center distributions and irregular harmonics placed at arbitrary points (which determine the electrostatic potential, field and field gradient, as well as higher order derivatives of the potential) can be expressed in terms of auxiliary functions of the same type as those appearing in the overlap. The recurrence relations and series expansions of these functions are thoroughly studied, and algorithms for their calculation are presented. The usefulness and efficiency of this procedure are tested by developing two independent codes: one for the derivatives of the overlap integrals with respect to the centers of the functions, and another for derivatives of the potential (electrostatic field, field gradient, and so forth) at arbitrary points. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2008
Effect of flavour components in lemon essential oil on physical or psychological stress
Authors: Fukumoto Syuichi , Morishita Aya , Furutachi Kohei , Terashima Takehiko , Nakayama Tsutomu , Yokogoshi Hidehiko 
Published: October 2007

AbstractCitrus essential oils, including lemon essential oil, have long been used widely in aromatherapy and alternative medicine. This study was designed to assess the effects of flavour components in lemon essential oil on physical and psychological stress. In this evaluation, acute cold stress and communication box techniques were used to apply stress after intraperitoneal administration of essential oil components such as limonene, γ‐terpinene and citral. Serum corticosterone and monoamines in brain tissues were then determined. In the present study, it found the presence of perillic acid, a limonene metabolite, at concentrations of 1.5–2.5 μg/mL in serum and 0.4–0.6 μg/g in brain tissue collected 3 h after administration. The research also showed that the lemon components R‐limonene, citral and γ‐terpinene inhibited elevation of serum corticosterone levels and cerebral monoamine levels. S‐limonene, a stereoisomer of R‐limonene, seemed to have stronger effect than other monoterpenes and inhibited brain monoamines elevation on psychological stress. These findings suggest that limonenes, and particularly S‐limonene, have a potent stress‐alleviating effect, and the possibility that different stereoisomers of limonene have different levels of activity in their effect on stress responses. These results suggest a possibility that ingestion of lemon essential oil containing components such as limonene and citral alleviates both physical and psychological stress. Copyright © 2007 John Wiley & Sons, Ltd.
Perceived psychosocial stress and cardiovascular risk: observations among the Bhutias of Sikkim, India
Authors: Sarkar Sobhanjan , Mukhopadhyay Barun 
Published: October 2007

AbstractPsychosocial factors (including psychosocial stress) are documented to be related to morbidity and mortality due to cardiovascular diseases (CVDs) and their risk factors. The present study examines whether perceived psychosocial stress affects blood pressures, blood lipids and obesity among the Bhutias, a tribal population of Sikkim. A total of 428 Bhutias of both sexes aged 20 years and above inhabiting both urban and rural areas participated after providing informed consent. Data on blood pressures, blood lipids, anthropometrics and a variety of lifestyle‐related factors including perceived stress level were collected following standard methods. The results clearly indicate that perceived stress significantly affects more than one CVD risk factor selected for study both in males and females. Perceived stress significantly affects diastolic blood pressure, total cholesterol (TC) and ratio of TC and high‐density lipoprotein (HDL) cholesterol in males, while in females, although significant effect of stress does not exist on blood pressures, significant effects of stress are discernible on Low‐density lipoprotein (LDL) cholesterol, TC/HDL as well as adiposity/obesity measures such as body mass index, waist circumference and waist–hip ratio. Perceived stress remains an independent factor affecting CVD risk factors even after controlling other significant lifestyle‐related predictors. Again, hypertension, both systolic and diastolic, overweight and obesity, have also been significantly affected by perceived stress. It appears that contribution of psychosocial stress in addition to other lifestyle‐related factors remains substantial among a tribal population inhabiting the eastern Himalaya and experiencing rapid socio‐cultural changes. Copyright © 2007 John Wiley & Sons, Ltd.
The regulation of affect, anxiety, and stressful arousal from adopting mastery‐avoidance goal orientations
Authors: Sideridis Georgios D. 
Published: October 2007

AbstractAchievement goal theory has proved to be very influential in our understanding of student's regulation of academic and non‐academic behaviours. Recently, Elliot and McGregor proposed mastery‐avoidance goals in the trichotomous model of achievement motivation. The purpose of the present studies was to examine the regulation of mastery‐avoidance goals with regard to persistence, affect and arousal. In Study 1, 96 college students' regulation of their own behaviour was assessed during a stressful exam. Results showed that mastery‐avoidance goals were associated with significantly elevated cognitive anxiety, negative affect and fear of failure. Study 2 attempted to replicate and extend the findings of Study 1 by examining the regulation of affect and arousal using self‐report and physiological assessments, during stressful in‐class presentations (n = 70). Results indicated that negative affect was significantly predicted by adoption of mastery‐avoidance goals. Modelling the effects using Multilevel Random Coefficient Modelling showed that students espousing mastery‐avoidance goals were significantly more aroused, compared to students who adopted any other type of goal orientation, at both the intercept level and the slope (linear or quadratic). It is concluded that mastery‐avoidance goals have deleterious effects on student's regulation of their emotional experience in stressful achievement situations and should be avoided by all means. Copyright © 2007 John Wiley & Sons, Ltd.
Stress, inflammatory markers and factors associated in patients with type 2 diabetes mellitus
Authors: Aguilar‐Zavala Herlinda , Garay‐Sevilla Ma. Eugenia , Malacara Juan Manuel , Pérez‐Luque Elva Leticia 
Published: October 2007

AbstractStress is evaluated using tumour necrosis factor‐α (TNF‐α), Heat Shock Protein 60 (Hsp60) and other markers in chronic diseases.We examined the association of Hsp60, cortisol, TNF‐α and interleukin‐6 (IL‐6) serum levels with psychological and socio‐economic factors in patients with type 2 diabetes mellitus (DM‐2).We studied 151 DM‐2 patients in groups with <1 year and >5 years since diagnosis. Clinical data, family income and questionnaires of anxiety, depression, perceived stress, social support, glucose, glycated haemoglobin, lipids, Hsp60, cortisol, IL‐6 and TNF‐α were collected.Patients with >5 years since diagnosis of DM‐2 had lower body mass index (p < 0.016), higher glucose (p < 0.005) and HbA1c (p < 0.005) levels. The group of recent diagnosis had higher Hsp60 (p < 0.00003). Hsp60 was associated negatively with years since diagnosis (p < 0.000012), and positively with glucose (p < 0.029). Cortisol was positively associated with glucose levels (p < 0.019) and family income (p < 0.037). TNF‐α was associated with years since diagnosis (p < 0.004) and perceived stress (p < 0.018).At early stages of DM‐2, Hsp60 increases with glucose levels, cortisol is associated with glucose levels. At later stages TNF‐α increases, associated with perceived stress. Copyright © 2007 John Wiley & Sons, Ltd.
Fabrication of Molecular Nanotemplates in Self‐Assembled Monolayers by Extreme‐Ultraviolet‐Induced Chemical Lithography
Authors: Turchanin Andrey , Schnietz Mark , El‐Desawy Mohamed , Solak Harun H. , David Christian , Gölzhäuser Armin 
Published: October 2007

AbstractExtreme‐UV interference lithography (EUV‐IL) is applied to create chemical nanopatterns in self‐assembled monolayers (SAMs) of 4′‐nitro‐1,1′‐biphenyl‐4‐thiol (NBPT) on gold. X‐ray photoelectron spectroscopy shows that EUV irradiation induces both the conversion of the terminal nitro groups of NBPT into amino groups and the lateral crosslinking of the underlying aromatic cores. Large‐area (≈2 mm2) nitro/amino chemical patterns with periods ranging from 2000 nm to 60 nm can be generated. Regions of pristine NBPT on the exposed samples are exchanged with protein‐resistant thiol SAMs of polyethyleneglycol, resulting in the formation of molecular nanotemplates, which can serve as the basis of complex biomimetic surfaces.
Test–retest variability and reliability of 123I‐IBZM SPECT measurement of striatal dopamine D2 receptor availability in healthy volunteers and influence of iterative reconstruction algorithms
Authors: Catafau Ana M. , Bullich Santiago , Danús Mónica , Penengo María M. , Cot Albert , Abanades Sergio , Farré Magí , Pavía Javier , Ros Domènec 
Published: October 2007

AbstractObjective: 123I‐IBZM single photon emission computed tomography (SPECT) is a widely used method to measure D2 receptor availability. However, test–retest variability and reliability have not been reported yet. This study aimed to further characterize 123I‐IBZM SPECT in healthy volunteers (HVs), by assessing (1) pseudoequilibrium interval after bolus injection; (2) normal specific uptake ratio (SUR) values using filtered‐backprojection (FBP); and the iterative reconstruction algorithm ordered‐subsets expectation maximization (OSEM); (3) test–retest variability and reliability (intraclass correlation coefficient); and (4) influence of OSEM on test–retest variability and reliability. Methods: Ten HVs (Group A) were scanned twice 48 h apart for test–retest variability and reliability measurements, and n = 4 of them were sequentially scanned over time. Eighteen HVs (Group B) were scanned once at pseudoequilibrium. For reconstruction FBP was used. Test–retest scans were reconstructed in addition using OSEM. SPECT‐MRI coregistration was used for region of interest drawing. Results: Pseudoequilibrium was achieved at 90 min postinjection (p.i.) and maintained until the end of the SPECT session (n = 4), and mean SUR at this time point was 0.96 ± 0.14 (Groups A + B, n = 28). Mean SUR at test was 0.96 ± 0.19 and at retest 0.94 ± 0.19 (Group A, n = 10). Using FBP, test–retest variability was (12.7 ± 9.6)% and reliability was 0.74. Using OSEM with 18 equivalent iterations, test–retest variability and reliability were improved to (6.5 ± 5.2)% and 0.84, respectively. Conclusions: 123I‐IBZM SPECT imaging using the bolus injection and a single scan at 90 min p.i. is a reproducible method showing acceptable test–retest variability and reliability. Test–retest variability and reliability can be substantially improved using OSEM with 12–36 equivalent iterations. Synapse 62:62–69, 2008. © 2007 Wiley‐Liss, Inc.