bluuebunny/crossref_metadata_2025 huggingface dataset:
Utilization of Olive‐Pomace Oil for Enzymatic Production of Cocoa Butter‐like Fat
Authors: Çiftçi Ozan Nazım , Fadıloğlu Sibel , Göğüş Fahrettin
Published: December 2008

Refined olive‐pomace oil (ROPO) was utilized as a source for the production of a cocoa butter (CB)‐like fat. Immobilized sn‐1,3 specific lipase‐catalyzed acidolysis of ROPO with palmitic (PA) and stearic (SA) acids was performed at various substrate mole ratios (ROPO:PA:SA) to produce major triacylglycerols (TAGs) of CB. Products obtained for various substrate mole ratios were compared to a commercial CB in terms of TAG content, melting profile, solid fat content (SFC) and microstructure. The fat produced at a substrate mole ratio of 1:2:6 was the most similar to CB. The product contained 11% POP, 21.8% POS, 15.7% SOS while commercial CB contained 18.9% POP, 33.1% POS and 24.7% SOS. The product had a melting peak of 29.9 °C while CB had one of 28.5 °C. Polarized light microscope (PLM) images showed that fat crystal network microstructures of this product and CB were very similar.
HDL concentration, lipid transfer to HDL, and HDL size in normolipidemic nonobese menopausal women
Authors: Giribela Arícia H. , Melo Nilson R. , Latrilha Maria C. , Baracat Edmundo C. , Maranhão Raul C
Published: December 2008

Objective

To determine the impact of menopause on lipid transfer from donor lipoproteins to high‐density lipoproteins (HDLs)—a process that is related to the protective function of HDL—and the size of HDL particles.

Method

Plasma from 22 premenopausal and 18 postmenopausal nonobese, normolipidemic women paired for age (40–50 years) was incubated in an artificial nanoemulsion labeled with radioactive lipids. Then the HDL fraction was assessed for radioactivity; the percentage of radioactive lipids transferred from the nanoemulsion to HDL was determined; and the size of HDL particles was measured by laser light scattering.

Results

There were no differences between the 2 groups in serum concentration of HDL cholesterol (61 ± 12 mg/dL vs 61 ± 14 mg/dL) or apolipoprotein A1 (1.5 ± 0.3 g/L vs 1.5 ± 0.2 g/L); lipid transfer to HDL; or size of HDL particles (8.8 ± 0.8 vs 9.0 ± 0.5 nm).

Conclusion

Menopause was not found to affect HDL cholesterol plasma concentration, lipid transfer to HDL, or size of HDL particles in normolipidemic nonobese women.
Ordinary Economic Voting Behavior in the Extraordinary Election of Adolf Hitler
Authors: KING GARY , ROSEN ORI , TANNER MARTIN , WAGNER ALEXANDER F.
Published: December 2008

The enormous Nazi voting literature rarely builds on modern statistical or economic research. By adding these approaches, we find that the most widely accepted existing theories of this era cannot distinguish the Weimar elections from almost any others in any country. Via a retrospective voting account, we show that voters most hurt by the depression, and most likely to oppose the government, fall into separate groups with divergent interests. This explains why some turned to the Nazis and others turned away. The consequences of Hitler's election were extraordinary, but the voting behavior that led to it was not.
Steers Afloat: The North Atlantic Meat Trade, Liner Predominance, and Freight Rates, 1870–1913
Authors: HARLEY C. KNICK
Published: December 2008

Meat transformed North Atlantic shipping, leading to dominance of liners and changed the economics of freight rates. Management coordination of meat shipment led to concentration in shipping. Only liner companies could provide specialized ships with the regularity needed and they dominated North Atlantic shipping. The cargo capacity of cattle ships, beyond that used for animals, lowered freight rates on grain below levels that would otherwise have prevailed. The berth rate on wheat from New York to Liverpool was most affected. Consequently, this readily available freight rate can be potentially misleading as an indicator of ocean shipping developments.
Corruption, Quasi-Rents, and the Regulation of Electric Utilities
Authors: NEUFELD JOHN L.
Published: December 2008

Was the adoption of state utility regulation the result of a negative-sum competition among special interest groups vying for the monopoly rents created by regulation or a positive-sum elimination of corruption arising from appropriable quasi-rents? Previous empirical studies of the adoption of regulation have assumed the former. Using discrete hazard analysis, this study considers the latter and finds the data more consistent with the positive-sum protection of quasi-rents than the negative-sum creation and appropriation of monopoly rents.
“Una fiera senza luogo”: Was Bisenzone an International Capital Market in Sixteenth-Century Italy?
Authors: PEZZOLO LUCIANO , TATTARA GIUSEPPE
Published: December 2008

From the mid-sixteenth to the early seventeenth century, Genoese bankers collected money from a variety of sources and lent it to the king of Spain. It was all made possible by the Bisenzone exchange fairs, which created an efficient financial network under Genoese control and permitted arbitrage among northern Italian financial markets. At Bisenzone, Genoese bankers raised money for these loans from a variety of sources, which reduced the risks of lending and funded the king's long-term obligations via short term loans. Bisenzone was in many ways an offshore capital market which operated on an international scale, or, in the language of the sixteenth century, a fair without a place—una fiera senza luogo.
Convergence of the UK OSGM05 GRACE‐based geoid and the UK fundamental benchmark network
Authors: Ziebart M. K. , Iliffe J. C. , Forsberg R. , Strykowski G.
Published: December 2008

The results of this study suggest that a traditional height network based on fundamental benchmarks can be used meaningfully to assess the quality of a satellite‐derived geoid model. We compare the pre‐ Gravity Recovery and Climate Experiment (GRACE) OSGM02 and the recent OSGM05 geoid models with the datum surface inferred by the UK fundamental benchmark network combined with network monument ellipsoidal heights derived from GPS data. OSGM05 incorporates long‐wavelength gravity field data from GRACE to degree/order 90. Switching from OSGM02 to OSGM05, the mean difference between the leveling datum and the geoid model reduces from −0.129 m to −0.004 m, and RMS differences reduce from 0.110 m to 0.048 m. The mean tilt between the height datum and the geoid model in the north‐south direction reduces from 34 mm to 12 mm per degree of latitude. Hence we demonstrate a systematic convergence between the geoid models and the leveling datum surface in terms of mean offset, RMS scatter and tilt without any fitting of one surface to the other. The implication is that the leveling datum surface represented a more accurate model of the geoidal geometry compared to OSGM02 in terms of form (in both short‐ and long‐wavelength features) and surprisingly also in terms of its offset from the GRS80 ellipsoid. While the latter point can be no more than a coincidence, the former indicates that the UK leveling network, based on its fundamental benchmark network, can be used to test the accuracy of geoid model improvements derived from missions such as GRACE, with implications for the forthcoming Gravity Field and Steady State Ocean Circulation Explorer (GOCE) mission.
NASA's Mars lander completes mission
Authors: Showstack Randy
Published: December 2008

After 5 months of providing scientists with a better understanding of Mars, and 2 months beyond the planned operational life, instruments on NASA's Phoenix Mars Lander are no longer receiving sufficient energy to operate due to an autumnal decline in sunlight reaching the lander's solar arrays, the agency announced on 10 November. The lander's last signal was received on 2 November, and scientists will be listening for any additional signals should the lander revive.

Since touching down on Mars on 25 May 2008, lander instruments verified the presence of water ice in the Martian subsurface. The lander has taken more than 25,000 pictures, among other accomplishments. Transmitted data have helped scientists learn more about the planet's arctic environment and whether it has ever been favorable for microbes. “Phoenix has given us some surprises, and I'm confident we will be pulling more gems from this trove of data for years to come,” said Phoenix principal investigator Peter Smith of the University of Arizona, in Tucson, which leads the mission.
Progress in Understanding Earth's Radiation Belts, Radiation Belts Saint Petersburg; Saint Petersburg, Russia, 4–6 August 2008
Authors: Goldstein Jerry , Shprits Yuri
Published: December 2008

Fifty years after their discovery, Earth's radiation belts are an enduring major challenge, owing to the complex, interdependent phenomena controlling these particles, and motivated by the enormous role of space technology in our society. The recent Radiation Belts Saint Petersburg (RBSPb) workshop explored how to meet this challenge.

Considerable discussion focused on learning more from observations, especially by revisiting existing spacecraft data sets with new analysis techniques or updated paradigms. New techniques were reported, such as extraction of energetic electron data from signal contamination in proton detectors and conversion of auroral proton images into global wave proxies. New insight concerning global aspects of the system (e.g., plasmaspheric wave‐particle interactions) enables less ambiguous interpretation of local measurements.
Ocean Carbon Cycling and Climate Impacts on Marine Ecosystems: Third Annual Ocean Carbon and Biogeochemistry Summer Science Workshop 2008; Woods Hole, Massachusetts, 21–24 July 2008
Authors: Benway Heather M. , Doney Scott
Published: December 2008

The Ocean Carbon and Biogeochemistry (OCB) program is a coordinating body for the U.S. research community that focuses on the ocean's role as a component of the global Earth system, bringing together research in geochemistry, ocean physics, and ecology to advance our understanding of ocean biogeochemistry. The third annual OCB summer science workshop, sponsored by the U.S. National Science Foundation, took place at Woods Hole Oceanographic Institution, convening 147 participants.

Daily plenary and poster sessions focused on three interdisciplinary themes: (1) climate sensitivity of ecosystem structure and associated impacts on biogeochemical cycles, (2) carbon uptake and storage, and (3) temporal trends in ecosystem variability.
Bioturbation From Square Millimeter to Global Scales: Bioturbation: An Update on Darwin's Last Idea; Renesse, Netherlands, 23–27 August 2008
Authors: Meysman Filip , Middleburg Jack
Published: December 2008

Marine sediments occupy about 70% of the Earth's surface and represent one of the most important interfaces in the Earth system because they regulate the transfer of carbon from the biosphere to the geosphere. A crucial control on carbon processing is exerted by the animals inhabiting the ocean floor, which extensively rework and oxygenate sediments while feeding and moving, a process referred to as bioturbation.

The significance of bioturbation was first realized by Charles Darwin, who devoted his final book to the subject. Recently, the second international meeting on bioturbation was organized in the Netherlands, following upon the success of the first meeting, in France (Marseille), in 2004. The purpose of this meeting was to provide a multidisciplinary update on the importance of bioturbation in sediment biogeochemistry, ecosystem functioning, and global biogeochemical cycles. Sixty scientists from 16 countries came together to address the physics, chemistry, geology, and biology of bioturbation in sediments and soils, in both the present and the past.
Idealized simulations of aerosol influences on tornadogenesis
Authors: Lerach David G. , Gaudet Brian J. , Cotton William R.
Published: December 2008

Numerical simulations of an idealized supercell thunderstorm were performed to assess effects of increased aerosol concentrations acting as cloud condensation nuclei (CCN) and giant CCN (GCCN) on tornadogenesis. Initial background profiles of CCN and GCCN concentrations were set to represent “clean” continental and aerosol‐polluted environments, respectively. With a reduction in warm‐ and cold‐rain processes, the polluted environment produced a longer‐lived supercell with a well‐defined rear flank downdraft (RFD) and relatively weak forward flank downdraft (FFD) that produced weak evaporative cooling, a weak cold pool, and an EF‐1 tornado. The clean environment produced no tornado and was less favorable for tornadogenesis.
Open magnetic flux and magnetic flux closure during sawtooth events
Authors: Hubert B. , Milan S. E. , Grocott A. , Cowley S. W. H. , Gérard J. C.
Published: December 2008

We use IMAGE‐FUV observations of the polar aurora and measurements of the ionospheric convection from the SuperDARN radar network to study several sawtooth events previously reported in the literature. We estimate the amount of open magnetic flux in the Earth magnetosphere during a significant part of these sawtooth intervals as well as the magnetic flux opening and closure rates, that is, the dayside and nightside reconnection rates. We find that during the sawtooth intervals the magnetosphere is highly loaded with open flux as a result of the strongly southward IMF carried by the solar wind during these intervals. The magnetosphere tries to relax to a less loaded configuration through a sequence of substorm expansions. However, these substorms do not necessarily evolve to their end before reintensification of nightside reconnection occurs in response to continued loading of the magnetosphere on the dayside.
Behavioral Genetics and Equality
Authors: Brock Dan
Published: December 2008

I will explore the implications of findings in behavioral genetics for two conceptions of equality: equality of opportunity and the equal moral worth of persons. New findings in behavioral genetics showing that behavioral traits, and the variance in behavioral traits, have some genetic underpinnings would not seem in themselves to threaten either of these notions of equality—we have long known that there is significant variation in these traits across persons and have assumed that some significant portion of that variation has genetic sources. I believe it is the uncertain and probably distant prospect of genetic interventions to enhance some behavioral traits, which could greatly increase the range and inequality of those traits in humans, that may seem to threaten these two notions of equality. I will argue that significant capacities to enhance behavioral traits could indeed threaten and erode equality of opportunity, but that it should not undermine the equal moral worth of persons.To watch my presentation, please see the "Google Video posting":http://video.google.com/videoplay?docid=7235940965176250693&hl=en.
Phenotypes, Social Constructionism and the Spurious Finding
Authors: Press Nancy
Published: December 2008

Dr. Press discussed behavioral genetics through the lens of social constructionism. She also discussed the phenomenon of medicalization, focusing on the example of smoking as a behavior.To watch Dr. Press's presentation, please see the "Google Video posting":http://video.google.com/videoplay?docid=522910112497476586&hl=en.
The tumour suppressor p53 regulates the expression of amyloid precursor protein (APP)
Authors: Cuesta Ascensión , Zambrano Alberto , Royo María , Pascual Angel
Published: December 2008

The expression of the APP (amyloid precursor protein), which plays a key role in the development of AD (Alzheimer's disease), is regulated by a variety of cellular mediators in a cell-dependent manner. In this study, we present evidence that p53 regulates the expression of the APP gene in neuroblastoma cells. Transient expression of ectopic p53, activation of endogenous p53 by the DNA-damaging drug camptothecin or Mdm2 (murine double minute 2) depletion decreases the intracellular levels of APP in murine N2aβ neuroblastoma cells. This effect was also observed in primary cultures of rat neurons as well as in SH-SY5Y cells, a human neuroblastoma cell line. Transient transfection studies using plasmids that contain progressive deletions of the 5′ region of the gene demonstrate that p53 represses APP promoter activity through a mechanism that is mediated by DNA sequences located downstream of the transcription start site (+55/+101). Accordingly, expression of a dominant-negative p53 mutant significantly increases the transcriptional activity of the APP promoter. In addition, results obtained in gel mobility-shift assays show that p53 does not bind to the +55/+101 APP region, although it reduces binding of the transcription factor Sp1 (stimulating protein 1). Reduction of Sp1 binding after activation of p53 with camptothecin was also observed in chromatin immunoprecipitation assays. Altogether, our results strongly suggest a mechanism by which p53 precludes binding of Sp1 to DNA, and therefore the stimulation of the APP promoter by this transcription factor.
Neuropsychological Consequences of Cancer and Cancer Treatment
Authors: Kean Jacob , Locke Dona E. C.
Published: December 2008

Purpose
: This review paper was written to facilitate greater understanding of functional cognitive deficits associated with cancer and cancer treatment. Rehabilitation of patients with cancer also has been considered in this review to raise awareness of this potentially underserved population.

Method
: A review of the literature pertaining to cognitive effects of cancer and cancer therapy was conducted.

Results and Conclusions
: A growing literature suggests the phenomenon popularly called “chemo brain” results from dysfunction of frontal-subcortical networks and manifests as deficits of executive functioning (e.g., reasoning, decision-making, resource allocation), processing speed, inhibition, and goal-oriented behaviors. Further research is needed, however, to attribute clearly these broad cognitive side effects to the disease process and each of several treatments and to establish the efficacy of cognitive rehabilitation for patients with cancer.
Cognitive and Communicative Consequences of Cardiovascular Disease
Authors: Murray Laura L.
Published: December 2008

Purpose
: A growing literature has documented that cardiovascular disease (CVD), even prior to causing strokes and other neurological disorders, can negatively affect cognitive and communicative functioning in children and adults. The purpose of this paper is to summarize current findings pertaining to the clinical management of cognitive and communicative changes associated with CVD by (a) reviewing common conditions, risk factors, and cognitive-communicative symptoms associated with CVD and (b) identifying strategies for assessing and treating the cognitive-communicative consequences of CVD.

Method
: The current empirical literature was critically reviewed to provide a brief overview of CVD conditions, risk factors, and occurrence statistics, followed by a summary of cognitive-communicative changes associated with CVD and management techniques that speech-language pathologists might utilize with this patient population.

Results and Conclusions
: Given the burgeoning prevalence of CVD, there is growing need for clinical understanding of CVD-related cognitive-communicative changes and the procedures appropriate for identifying and managing these changes in the diverse CVD population. Several lines of investigation, however, must be pursued to assure that the diagnostic and management suggestions provided in the current review are appropriate and to delineate further the role speech-language pathology can play in maximizing functional outcomes in individuals with CVD.
Development of new in situ observation system for dynamic study of lubricant molecules on metal friction surfaces by two-dimensional fast-imaging Fourier-transform infrared-attenuated total reflection spectrometer
Authors: Sasaki Keiji , Inayoshi Naruhiko , Tashiro Kohji
Published: December 2008

To observe the time-dependent two-dimensional (2D) images of spatial distribution of chemically/physically modified lubricant molecules on the metal surface during friction motion, a new in situ technique has been developed by combining the 2D fast-imaging Fourier-transform infrared-attenuated total reflection spectrometer with the temperature-controlled friction equipment containing lubricant agent. Using this new instrument, the time-dependent changes in lubricant molecules, for example, cis-trans isomerization, stress-induced molecular deformation, etc., can be detected successfully. The characteristic features of this instrument have been demonstrated in a detailed and concrete manner by demonstrating the experimental data measured for oleic acid and tricresyl phosphate.
Perception-action map learning in controlled multiscroll systems applied to robot navigation
Authors: Arena Paolo , De Fiore Sebastiano , Fortuna Luigi , Patané Luca
Published: December 2008

In this paper a new technique for action-oriented perception in robots is presented. The paper starts from exploiting the successful implementation of the basic idea that perceptual states can be embedded into chaotic attractors whose dynamical evolution can be associated with sensorial stimuli. In this way, it can be possible to encode, into the chaotic dynamics, environment-dependent patterns. These have to be suitably linked to an action, executed by the robot, to fulfill an assigned mission. This task is addressed here: the action-oriented perception loop is closed by introducing a simple unsupervised learning stage, implemented via a bio-inspired structure based on the motor map paradigm. In this way, perceptual meanings, useful for solving a given task, can be autonomously learned, based on the environment-dependent patterns embedded into the controlled chaotic dynamics. The presented framework has been tested on a simulated robot and the performance have been successfully compared with other traditional navigation control paradigms. Moreover an implementation of the proposed architecture on a Field Programmable Gate Array is briefly outlined and preliminary experimental results on a roving robot are also reported.
Efficient elimination of response parameters in molecular property calculations for variational and nonvariational energies
Authors: Kristensen Kasper , Jørgensen Poul , Thorvaldsen Andreas J. , Helgaker Trygve
Published: December 2008

A general method is presented for the efficient elimination of response parameters in molecular property calculations for variational and nonvariational energies. For variational energies, Wigner’s 2n+1 rule is obtained as a special case of the more general k2n+1 rule, which states that for a subset of k perturbations within a total set of z≥k perturbations, response parameters may be eliminated according to the 2n+1 rule (normally applied to the full set of perturbations). Nonvariational energies may be treated by introducing Lagrange multipliers that satisfy the stronger 2n+2 rule for the k perturbations, while the wave-function parameters still satisfy the 2n+1 rule for the k perturbations. The corresponding rule for nonvariational energies is referred to as the k2n+1,2n+2 rule. For k=z, the well-known 2n+2 rule for the multipliers is reproduced, while the wave-function parameters satisfy the 2n+1 rule. The application of the k2n+1 and k2n+1,2n+2 rules minimizes the total number of response equations to be solved when the molecular property contains k extensive perturbations (e.g., geometrical derivatives) and z−k intensive perturbations (e.g., electric fields).
Coumarin dyes for dye-sensitized solar cells: A long-range-corrected density functional study
Authors: Wong Bryan M. , Cordaro Joseph G.
Published: December 2008

The excited-state properties in a series of coumarin solar cell dyes are investigated with a long-range-corrected (LC) functional which asymptotically incorporates Hartree–Fock exchange. Using time-dependent density functional theory (TDDFT), we calculate excitation energies, oscillator strengths, and excited-state dipole moments in each of the dyes as a function of the range-separation parameter μ. To investigate the acceptable range of μ and to assess the quality of the LC-TDDFT formalism, an extensive comparison is made between LC-BLYP excitation energies and approximate coupled-cluster singles and doubles calculations. When using a properly optimized value of μ, we find that the LC technique provides a consistent picture of charge-transfer excitations as a function of molecular size. In contrast, we find that the widely used B3LYP hybrid functional severely overestimates excited-state dipole moments and underestimates vertical excitation energies, especially for larger dye molecules. The results of the present study emphasize the importance of long-range exchange corrections in TDDFT for investigating the excited-state properties in solar cell dyes.
Effect of native oxide mechanical deformation on InP nanoindentation
Authors: Almeida C. M. , Prioli R. , Ponce F. A.
Published: December 2008

Native oxide has been found to have a noticeable effect on the mechanical deformation of InP during nanoindentation. The indentations were performed using spherical diamond tips and the residual impressions were studied by atomic force microscopy. It has been observed that in the early stages of mechanical deformation, plastic flow occurs in the oxide layer while the indium phosphide is still in the elastic regime. The deformed native oxide layer results in a pile-up formation that causes an increase in the contact area between the tip and the surface during the nanoindentation process. This increase in the projected contact area is shown to contribute to the apparent high pressure sustained by the crystal before the onset of plastic deformation. It is also shown that the stress necessary to generate the first dislocations from the crystal surface is ∼3 GPa higher than the stress needed for slip to occur when dislocations are already present in the crystalline structure.
Comparison of optical parameters and luminescence between Er3+/Yb3+ codoped phosphate glass ceramics and precursor glasses
Authors: Yu Xiaochen , Song Feng , Wang Wentao , Luo Lanjun , Han Lin , Cheng Zhenzhou , Sun Tongqing , Tian Jianguo , Pun Edwin. Y. B.
Published: December 2008

Er 3 + / Yb 3 + codoped transparent phosphate precursor glasses and glass ceramics have been fabricated and characterized. The formation of ErPO4 and YbPO4 nanocrystals was studied using x-ray diffraction. The intensity parameters, the spontaneous radiative transition probabilities, the branching ratios, and the radiative lifetimes of Er3+ in both glass ceramics and precursor glasses were calculated based on the Judd–Ofelt theory, and the crystallization process in the glass ceramics is confirmed by the optical parameters obtained. Under 975 nm wavelength excitation intense 1.54 μm fluorescence and upconversion luminescence were observed in the glass ceramics, the quantum efficiency of the Er3+ I413/2→I415/2 transition is 95%, and the transition mechanisms of the upconversion luminescence are due to a two-photon process.
Improvements and applications of entrainment control for nonlinear dynamical systems
Authors: Liu Fang , Song Qiang , Cao Jinde
Published: December 2008

This paper improves the existing entrainment control approaches and develops unified schemes to chaos control and generalized (lag, anticipated, and complete) synchronization of nonlinear dynamical systems. By introducing impulsive effects to the open-loop control method, we completely remove its restrictions on goal dynamics and initial conditions, and derive a sufficient condition to estimate the upper bound of impulsive intervals to ensure the global asymptotic stability. We then propose two effective ways to implement the entrainment strategy which combine open-loop and closed-loop control, and we prove that the feedback gains can be chosen according to a lower bound or be tuned with an adaptive control law. Numerical examples are given to verify the theoretical results and to illustrate their applications.
Traveling-wave solutions of the flow in a curved-square duct
Authors: Yanase Shinichiro , Watanabe Takeshi , Hyakutake Toru
Published: December 2008

Three-dimensional (3D) calculations of the flow through a curved duct of square cross section are conducted by use of the spectral method. The main concern of this paper is to clarify 3D structures of periodic solutions which have been obtained by two-dimensional (2D) calculations assuming uniformity in the main-flow direction. It is found that traveling-wave solutions are realized by 3D numerical simulations in the parameter region where periodic solutions were obtained by 2D simulations. Exact traveling-wave solutions are obtained by the iteration method from an initial guess given by the time-evolution calculations. The flow patterns of a 3D traveling wave observed in a cross section are very similar to those of 2D periodic solutions.
Exciton recombination energy in spherical quantum dots on Ga1−xInxAsySb1−y/GaSb grown by liquid-phase epitaxy
Authors: Sánchez-Cano R. , Tirado-Mejía L. , Fonthal G. , Ariza-Calderón H. , Porras-Montenegro N.
Published: December 2008

Photoluminescence and photoreflectance responses at 12 K of Ga1−xInxAsySb1−y films grown over GaSb single-crystal substrates by liquid-phase epitaxy do not exhibit the same energy values. The photoluminescence peak shifts to 20 meV in relation to the photoreflectance response, indicating a possible electronic confinement in some parts of the growth heterostructure. The possibility of low-dimensional structures is investigated herein. They are possibly formed during the growth process and are responsible for this energy shift. The optical emission spectra associated with transitions between the first conduction and valence-band levels in spherical Ga1−xInxAsySb1−y/GaSb quantum dots, using x and y values in the range of 0.11–0.15 and 0.10–0.14, respectively, are studied here. These ranges were chosen according to experimental results obtained from the samples under study. Spherical potential wells of finite depth determined by the discontinuity in the conduction band ΔEC for electrons and the discontinuity in the valence band ΔEV for holes were used. In the calculations, the variational procedure within the effective-mass approximation was used and electrons and holes in a type-I band alignment formed by two semiconductors with similar parabolic conduction bands were considered. From these results, it was concluded that higher electronic confinements such as quantum dots were possibly formed during the growth process in some areas of the heterostructure.
Variation in electrical resistance versus strain of an individual multiwalled carbon nanotube
Authors: Jang Hoon-Sik , Lee Yun-Hee , Na Ho-Jun , Nahm Seung Hoon
Published: December 2008

The electrical resistance of an individual multiwalled carbon nanotube (MWCNT) as a function of mechanical strain was investigated inside a scanning electron microscope. The mechanical strain was applied to the MWCNT by a tungsten tip controlled by a nanomanipulator. The contact resistance between an individual MWCNT and the tungsten tip decreased with the addition of carbon deposition during e-beam exposure. The electrical resistance was significantly changed during the elongation process of the MWCNT and corresponded with the nanotube strain. The resistance increased abruptly at the beginning of the tube fracture. The strain sensitivities of two individual MWCNT were calculated to be about 25.2 and 25.9, respectively. The unique characteristics in electrical resistance variation for different displacements of an individual MWCNT could be used in a strain gauge for strain sensing of nanomaterials or a micromechanical device for sensing force or pressure. CNTs are very strong and highly flexible and would be ideal for these applications.
Measurements of optical cross sections of the carbon vacancy in 4H-SiC by time-dependent photoelectron paramagnetic resonance
Authors: Dashdorj J. , Zvanut M. E. , Harrison J. G.
Published: December 2008

Time-dependent photoinduced electron paramagnetic resonance measurements have been made on high purity semi-insulating 4H-SiC to develop a more complete understanding of the optical transitions of the positively charged carbon vacancy VC+. The single defect model originally proposed is given validity by demonstrating that the time dependence of the photoinduced changes in VC+ may be fitted by a first order kinetic process. In addition, the photon energy dependence of the optical cross sections for capture and emission of electrons from VC+ is extracted by incorporating both processes into one expression for charge transfer. The data are interpreted by considering the role of the electronic density of states as well as participation of phonons. Analysis assuming only phonon participation yields thermal and optical energies of 1.6 and 2.15 eV, respectively, for charge transitions between VC+ and one of the band edges. Charge transfer between VC+ and the opposite band edge is associated with a thermal and an optical energy of 1.9 and 2.45 eV, respectively. An upper limit for the Franck–Condon shift of 0.55 eV is extracted from the difference between the thermal and optical energies.
Electrical properties measurements on individual carbon nanofibers by scanning spreading resistance microscopy
Authors: Fourdrinier L. , Le Poche H. , Chevalier N. , Mariolle D. , Rouviere E.
Published: December 2008

Vertically aligned 850-nm-long carbon nanofibers (CNFs) are grown on a titanium nitride (TiN) layer by a radio-frequency plasma system at 560 °C. Electrical properties of individual CNFs are statistically determined by a current sensing atomic force microscopy mode. An interpretation based on electrical contact resistance model classically used to describe macroscopic observations, combined with a semiclassical approach commonly used for such nano-objects, is proposed here to explain dispersion in obtained values. Roughness of the TiN layer is responsible for this dispersion by varying contact surface between CNF and the TiN layer, while interface oxidation equally affects the transport by adding a barrier at the interface. Some CNFs exhibit very low resistances (few kilohms), implying that good contact is obtained between the nanofiber and the substrate, while others CNFs exhibit high resistance, attributed to local poor electrical contacts between CNFs and TiN layer.
Influence of unintentional doped carbon on growth and properties of N-doped ZnO films
Authors: Chen Hui , Gu Shulin , Liu Wei , Zhu Shunming , Zheng Youdou
Published: December 2008

The evolution of optical and electrical properties induced by rapid thermal annealing is studied on nitrogen-doped ZnO samples grown by metal-organic chemical vapor deposition (MOCVD). Correspondingly, in the Raman spectra carbon cluster related D and G modes have been observed to increase with annealing temperature. The increase in the intensity ratio of D and G modes indicates growing of carbon clusters, revealing an interesting change in unintentional doped carbon, which is a popular impurity in MOCVD grown N-doped ZnO. Substitutional or interstitial carbons in the grains may migrate to grain boundaries to incorporate with some existing carbon clusters to form larger ones. Accordingly, zinc vacancies will then be easily formed as annealing temperature increased, resulting in eminent green band emission at room temperature photoluminescence. The band edge emissions also show significant changes with several shoulders observed by thermal annealing, which can be ascribed to acceptor or donor related emissions. The changes in emissions agree well with the evolution of the electrical property of annealed samples. This study shows that unintentional doped carbon has a great influence on ZnO growth by forming clusters in the grain boundary area and also on the optical and electrical properties by forming C related defects in the grains.
Pyroelectric potassium hydrogen malate with polarized hydrogen bond chains and aligned dipole moments
Authors: de Matos Gomes E. , Belsley M. S. , Criado A. , Rodrigues V. H. , Costa M. M. R.
Published: December 2008

A spontaneous polarization of 16 μC/cm2 at room temperature has been found in the semiorganic crystal potassium hydrogen malate (KHC4H4O5⋅H2O). This high polarization results from a structural arrangement of oriented dipoles formed by the potassium cations and the COO− group from the malate anion, and long hydrogen bonded polarized chains created by the hydrogen L-malate anion via O–H⋯O interactions, directed along the polar sixfold axis. The material shows a second harmonic generation with a rotationally averaged effective second order susceptibility equal to 0.70 of potassium dihydrogen phosphate at an incident wavelength of 1064 nm.
Land-contrast self-referencing interferometric protein microarray
Authors: Wang Xuefeng , Zhao Ming , Nolte David D.
Published: December 2008

We present a nonfluorescent protein microarray, the land-contrast BioCD, on which interferometric contrast is induced by a patterned substrate rather than by patterned protein. The substrate is an oxidized silicon wafer with etched spot patterns. Within the spots the SiO2 thickness is 140 nm and on the land it is 77 nm. The spot and the land have equal reflectance but opposite interferometric quadrature responses for protein layer. Protein is evenly immobilized on the entire chip and detected by reflectometry. The contrast between spot and land is directly converted to protein thickness.
Fabrication of three dimensional porous silicon distributed Bragg reflectors
Authors: Mangaiyarkarasi D. , Breese M. B. H. , Ow Y. S.
Published: December 2008

Three-dimensional distributed Bragg reflectors, which reflect all incident wavelengths, have been fabricated with micrometer dimensions in porous silicon, resulting in white reflective surfaces when viewed over a wide angular range. Large area arrays of several mm2 containing many individual micrometer-size pixellated reflectors that can be tuned to reflect a narrow or wide range of wavelengths are designed to appear either as constant or changing reflective images to the naked eye. This work opens avenues in controlling the reflection of light in all directions for applications in wide-angle displays, broadband reflective surfaces for resonant white light emission from semiconductor nanocrystals, and three-dimensional microcavities.
Crystallization-induced stress in thin phase change films of different thicknesses
Authors: Guo Qiang , Li Minghua , Li Yi , Shi Luping , Chong Tow Chong , Kalb Johannes A. , Thompson Carl V.
Published: December 2008

We have studied crystallization-induced stress in phase change films (Ge2Sb2Te5) as a function of thickness and with and without a capping layer, by measuring the deflection of microcantilevers. The stress is found to increase with decreasing film thickness. A thin dielectric capping layer leads to a further increase in stress compared to uncapped films. This observation can be explained by the suppression of stress relaxation in the phase change film in the presence of a capping layer. High stress will affect device performance as the size of phase change memory cells decreases.
Are Northern Ireland's Communities Dividing? Evidence from Geographically Consistent Census of Population Data, 1971–2001
Authors: Shuttleworth Ian G , Lloyd Christopher D
Published: December 2008

There is an extensive literature on various aspects of segregation in Northern Ireland (NI). However, there are no census-based analyses of population change and residential segregation that cover the entire 1971–2001 period using consistent geographical units through time for all NI. This shortcoming is addressed in this paper by an analysis of changes in (i) the spatial distribution of population and (ii) residential segregation between 1971 and 2001 using the NI Grid-Square Product comprising data for a set of 1km2 cells that cover all populated areas in NI. The substantive issue of whether NI has become more segregated through time is addressed as are questions about measuring change through time using the census and the importance of spatial scale. One important conclusion is that NI indeed became more residential^ segregated between 1971 and 2001, but that residential segregation in 2001 remained approximately at its 1991 level according to most indicators.
Revision of the genus Trogulus Latreille: the Trogulus coriziformis species-group of the western Mediterranean (Opiliones:Trogulidae)
Authors: Schönhofer Axel L. , Martens Jochen
Published: December 2008

Within the well researched European fauna of harvestmen, the genus Trogulus Latreille exhibits unexpectedly high cryptic diversity. The species’ uniform morphology hinders an exclusively morphological approach to their systematics and taxonomy, and a preliminary molecular study estimated the number of species to be three times higher than currently known. The current study focuses on a clearly defined species-group within Trogulus, combining molecular (~1700 bp 28S rRNA and the cytochrome b gene), distributional, morphometric and morphological data. Relationships are reconstructed using Bayesian inference, maximum parsimony and maximum likelihood and this information is subsequently used to evaluate morphological characters for systematic usability and to identify biogeographical processes leading to speciation events. The Trogulus coriziformis species-group is defined and diagnosed and includes eight species. Three species are redefined: T. coriziformis C. L. Koch, 1839, for which a neotype is designated, and T. aquaticus Simon, 1879 and T. cristatus Simon, 1879 for which lectotypes are designated. Four species are described as new: T. balearicus, sp. nov. from the Balearic Islands, T. huberi, sp. nov. from southern Portugal, T. prietoi, sp. nov. from Andalusia, Spain, and T. pyrenaicus, sp. nov. from the central Pyrenees. Trogulus lusitanicus Giltay, 1931 is used as collective name and probably refers to a composite of species presently difficult to tell apart. Trogulus salfii De Lerma, 1948 is proposed as a synonym for T. coriziformis. Within Trogulus, the molecular genetic data support monophyly and basal placement of the Trogulus coriziformis species-group. The species to differ in external morphology (size, papillation of palps, apophyses of legs, pattern of body papillation, morphometric data), 28S and cytochrome b autapomorphies and to a lesser degree by male genital morphology. The species-group is confined to the western Mediterranean area and its species are allopatrically distributed. Their present distribution corresponds to geological processes in the Miocene and Pliocene indicating that this group of organisms may be of considerable value for further biogeographic studies.
Age-dependent and age-independent human memory persistence is enhanced by delayed posttraining methylphenidate administration
Authors: Izquierdo Iván , Bevilaqua Lia R. , Rossato Janine I. , Lima Ramón H. , Medina Jorge H. , Cammarota Martín
Published: December 2008

Healthy human volunteers 16–82 years of age with at least 10 years of schooling were exposed to two different memory tasks. The first task involved incidental memory. The subjects were asked, as casually as possible: “Did you watch any movie on TV 2 days ago? And 7 days ago? If so, do you remember the title of the movie(s) and the name of the first two actors (actresses)?” Retention scores (maximum = 3: title, actor 1, and actor 2) were equally high (overall mean = 2.6,
n
= 61) in all age groups (16–20, 21–30, 31–40, 41–60, and 61–82 years) for the day 2 scores. Scores for the movie seen 7 days before decreased significantly and progressively in the three older groups in relation to age, which indicates reduced persistence of this type of memory beginning at the age of 41–50 years and becoming more extensive over the years. The other task was a formal memory procedure. Subjects were asked to study a brief text with factual information on the 1954 World Soccer Cup for 10 min. They were then exposed to 10 questions on the text 2 days and, again, 7 days later. Retention scores declined between the two tests, but in this task, the decline of persistence occurred to a similar extent in all age groups, and thus was not dependent on age. Methylphenidate (10 mg p.o.) given 12 hours after acquisition markedly enhanced persistence of the two memory types. This suggests an involvement of dopaminergic processes in persistence in the late posttraining period.
Requirement for binding multiple ATPs to convert a GroEL ring to the folding-active state
Authors: Chapman Eli , Farr George W. , Fenton Wayne A. , Johnson Steven M. , Horwich Arthur L.
Published: December 2008

Production of the folding-active state of a GroEL ring involves initial cooperative binding of ATP, recruiting GroES, followed by large rigid body movements that are associated with ejection of bound substrate protein into the encapsulated hydrophilic chamber where folding commences. Here, we have addressed how many of the 7 subunits of a GroEL ring are required to bind ATP to drive these events, by using mixed rings with different numbers of wild-type and variant subunits, the latter bearing a substitution in the nucleotide pocket that allows specific block of ATP binding and turnover by a pyrazolol pyrimidine inhibitor. We observed that at least 2 wild-type subunits were required to bind GroES. By contrast, the triggering of polypeptide release and folding required a minimum of 4 wild-type subunits, with the greatest extent of refolding observed when all 7 subunits were wild type. This is consistent with the requirement for a “power stroke” of forceful apical movement to eject polypeptide into the chamber.
Microcirculation and the Physiome Projects
Authors: BASSINGTHWAIGHTE JAMES B.
Published: December 2008

The Physiome projects comprise a loosely knit worldwide effort to define the Physiome through databases and theoretical models, with the goal of better understanding the integrative functions of cells, organs, and organisms. The projects involve developing and archiving models, providing centralized databases, and linking experimental information and models from many laboratories into self‐consistent frameworks. Increasingly accurate and complete models that embody quantitative biological hypotheses, adhere to high standards, and are publicly available and reproducible, together with refined and curated data, will enable biological scientists to advance integrative, analytical, and predictive approaches to the study of medicine and physiology. This review discusses the rationale and history of the Physiome projects, the role of theoretical models in the development of the Physiome, and the current status of efforts in this area addressing the microcirculation.
Finite‐Element‐Based Design Optimisation of a Novel High Flexion Knee Used in Total Knee Arthroplasty
Authors: Sivarasu Sudesh , Mathew Lazar
Published: December 2008

The application of finite‐element modelling in medical applications has been evolving as a field of high importance in recent times. Total knee arthroplasty (TKA) has been in existence for over 6 decades. The generic artificial knee implants used in the TKA have a restricted range of motion of around 90 degrees. A new design allowing a flexion extension range of over 120 degrees was designed and is used for analysis. Loading conditions of 10 times the body weight are considered. The finite‐element analyses of the designs were carried out based on standard biomaterials used in orthopaedic implants. The results of the analyses were used in identifying areas of extreme stress within the design and the spots prone to higher deformation. On the basis of these results slight modification of the designs was carried out. The results are also verified whether the body is within the linear deformation levels. The results obtained were very satisfactory and based on these results the models have been recommended for prototyping.