bluuebunny/crossref_metadata_2025 huggingface dataset:
Metamaterial focusing device for microwave hyperthermia
Authors: Velázquez‐Ahumada María C. , Freire Manuel J. , Marqués Ricardo
Published: September 2011

This work shows a microwave focusing device based on metamaterials which can find application in hyperthermia of tumors. The device consists of an array of split‐ring resonators placed between two parallel metal plates. Both the fields and the temperature distribution are numerically obtained in a model of breast tissue and a tumor by modeling the device as a homogeneous uniaxial slab of negative permeability placed between the two metal plates. The theoretical predictions about the field distribution have been experimentally checked by measuring the field produced by the fabricated device inside a phantom resembling the breast tissue. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:2868–2872, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26434
Designing a non‐inferiority study in kidney transplantation: a case study
Authors: Witte Steffen , Schmidli Heinz , O'Hagan Anthony , Racine Amy
Published: September 2011

In organ transplantation, placebo‐controlled clinical trials are not possible for ethical reasons, and hence non‐inferiority trials are used to evaluate new drugs. Patients with a transplanted kidney typically receive three to four immunosuppressant drugs to prevent organ rejection. In the described case of a non‐inferiority trial for one of these immunosuppressants, the dose is changed, and another is replaced by an investigational drug. This test regimen is compared with the active control regimen. Justification for the non‐inferiority margin is challenging as the putative placebo has never been studied in a clinical trial. We propose the use of a random‐effect meta‐regression, where each immunosuppressant component of the regimen enters as a covariate. This allows us to make inference on the difference between the putative placebo and the active control. From this, various methods can then be used to derive the non‐inferiority margin. A hybrid of the 95/95 and synthesis approach is suggested. Data from 51 trials with a total of 17,002 patients were used in the meta‐regression. Our approach was motivated by a recent large confirmatory trial in kidney transplantation. The results and the methodological documents of this evaluation were submitted to the Food and Drug Administration. The Food and Drug Administration accepted our proposed non‐inferiority margin and our rationale. Copyright © 2011 John Wiley & Sons, Ltd.
Continuity and discontinuity of depressed mood from late adolescence to young adulthood: The mediating and stabilizing roles of young adults’ socioeconomic attainment
Authors: Wickrama K.A.S. , Conger Rand D. , Lorenz Federick O. , Martin Monica
Published: September 2011

Using prospective, longitudinal data from 467 youth over a 13‐year period (late adolescence and young adulthood), the present study investigates three research questions: (1) to what extent do elevations in depressed mood continue (homotypic continuity) from adolescence to young adulthood, (2) to what extent do young adults’ socioeconomic attainments and failures sustain the depressed mood from adolescence to young adulthood, and (3) to what extent do young adults’ socioeconomic attainments or failures mediate the continuity and discontinuity of depressive symptoms across this period? The results from our structural equation modeling (SEM) analyses suggest that continuity of depressive symptoms from late adolescence to young adulthood is mediated in part by economic and work achievements or failures of young adults after controlling for adolescent conduct disorder/antisocial behavior, parents’ psychopathology and family adversity. Additionally, the results indicate that the continuity of depressed mood across the early life course is conditioned (stabilized or disrupted) by young adult socioeconomic achievements or failures.
Neuropathic pain models in the development of analgesic drugs
Authors: Honoré Per Hartvig , Basnet Anna , Eljaja Laila , Kristensen Pernille , Andersen Lene Munkholm , Neustrup Signe , Møllgaard Pia , Bjerrum Ole J.
Published: September 2011

Introduction

Animal disease models are predictive for signs seen in disease. They may rarely mimic all signs in a specific disease in humans with respect to etiology, cause or development. Several models have been developed for different pain states and the alteration of behavior has been interpreted as a response to external stimulus or expression of pain or discomfort. Considerable attention must be paid not to interpret other effects such as somnolence or motor impairment as a pain response and similarly not to misinterpret the response of analgesics.

Neuropathic pain is caused by injury or disease of the somatosensory system. The clinical manifestations of neuropathic pain vary including both stimulus-evoked and non-stimulus evoked (spontaneous) symptoms. By pharmacological intervention, the threshold for allodynia and hyperalgesia in the various pain modalities can be modulated and measured in animals and humans. Animal models have been found most valuable in studies on neuropathic pain and its treatment.

Aim of the study

With these interpretation problems in mind, the present text aims to describe the most frequently used animal models of neuropathic pain induced by mechanical nerve injury.

Methods

The technical surgical performance of these models is described as well as pain behavior based on the authors own experience and from a literature survey.

Results

Nerve injury in the hind limb of rats and mice is frequently used in neuropathic pain models and the different types of lesion may afford difference in the spread and quality of the pain provoked. The most frequently used models are presented, with special focus on the spared nerve injury (SNI) and the spinal nerve ligation/transection (SNL/SNT) models, which are extensively used and validated in rats and mice. Measures of mechanical and thermal hypersensitivity with von Frey filaments and Hargreaves test, respectively, are described and shown in figures.

Conclusions

A number of animal models have been developed and described for neuropathic pain showing predictive value in parallel for both humans and animals. On the other hand, there are still large knowledge gaps in the pathophysiologic mechanisms for the development, maintenance and progression of the neuropathic pain syndrome

Implications

Better understanding of pathogenic mechanisms of neuropathic pain in animal models may support the search for new treatment paradigms in patients with complex neuropathic pain conditions
Numerical simulation of two-dimensional Faraday waves with phase-field modelling
Authors: Takagi Kentaro , Matsumoto Takeshi
Published: September 2011

A fully nonlinear numerical simulation of two-dimensional Faraday waves between two incompressible and immiscible fluids is performed by adopting the phase-field method with the Cahn–Hilliard equation due to Jacqmin (J. Comput. Phys., vol. 155, 1999, pp. 96–127). Its validation is checked against the linear theory. In the nonlinear regime, qualitative comparison is made with an earlier vortex-sheet simulation of two-dimensional Faraday waves by Wright, Yon & Pozrikidis (J. Fluid Mech., vol. 400, 2000, pp. 1–32). The vorticity outside the interface region is studied in this comparison. The period tripling state, which is observed in the quasi-two-dimensional experiment by Jiang, Perlin & Schultz (J. Fluid Mech., vol. 369, 1998, pp. 273–299), is successfully simulated with the present phase-field method.
Isomer-specific effects of conjugated linoleic acid on blood pressure, adipocyte size and function
Authors: DeClercq V. , Taylor C. G. , Zahradka P.
Published: September 2011

Obesity-related hypertension may be caused by activation of the local adipose tissue renin–angiotensin system, resulting in exaggerated production of the vasoconstrictor angiotensin II. Additionally, secretion of adiponectin from adipose tissue, which prevents endothelial dysfunction, is altered in obesity. Consumption of conjugated linoleic acid (CLA) has been shown to modulate cytokine release from adipocytes and positively influence blood pressure in younger rats, but its physiological actions in older models with established hypertension and isomer-specific effects on adipocyte size remain to be determined. Therefore, we investigated the effects of CLA isomers on adipocyte size in relation to blood pressure and adipokine production by hypertrophic adipocytes in older fa/fa Zucker rats with established hypertension. fa/fa Zucker rats were fed with cis(c)9, trans(t)11-CLA or t10, c12-CLA isomers for 8 weeks and compared with lean and obese rats fed with the control diet. Blood pressure and adipocyte size were subsequently measured. Collagenase-isolated adipocytes were size-separated and angiotensinogen and adiponectin protein levels quantified by Western blotting. The t10, c12-CLA group had reduced blood pressure, fewer large adipocytes and increased serum adiponectin. Angiotensinogen was present at higher levels in the large adipocytes, whereas the converse was observed for adiponectin. The beneficial effects of the t10, c12-CLA isomer on blood pressure and adipocyte size in vivo may be due to its ability to reduce the number of large adipocytes, which alters the levels of vasoactive molecules secreted from adipose tissue.
SEX DIFFERENCES IN INFANT MORTALITY IN SPITALFIELDS, LONDON, 1750–1839
Authors: HUMPHREY LOUISE , BELLO SILVIA , ROUSHAM EMILY
Published: September 2011

This study examines sex differences in infant mortality in Spitalfields, London, and the estimated contribution of endogenous and exogenous factors to neonatal and infant mortality using the biometric model from 1750 to 1839. There was a marked decline in the risk of death during infancy and the neonatal period for both sexes during the study period. There was significant excess male infant mortality compared with that of females in the 1750–59 cohort, estimated from baptism and burial registers, but not in later cohorts. Similarly, males had higher neonatal mortality rates than females in 1750–59 but not in later cohorts. Biometric analyses suggest that the observed decrease in neonatal mortality in both sexes was caused by a reduction in both endogenous and exogenous causes of death. The contribution of maternal health and breast-feeding practices to the observed patterns of mortality is discussed in the light of available evidence.
Categories versus dimensions in personality and psychopathology: a quantitative review of taxometric research
Authors: Haslam N. , Holland E. , Kuppens P.
Published: September 2011

Taxometric research methods were developed by Paul Meehl and colleagues to distinguish between categorical and dimensional models of latent variables. We have conducted a comprehensive review of published taxometric research that included 177 articles, 311 distinct findings and a combined sample of 533 377 participants. Multilevel logistic regression analyses have examined the methodological and substantive variables associated with taxonic (categorical) findings. Although 38.9% of findings were taxonic, these findings were much less frequent in more recent and methodologically stronger studies, and in those reporting comparative fit indices based on simulated comparison data. When these and other possible confounds were statistically controlled, the true prevalence of taxonic findings was estimated at 14%. The domains of normal personality, mood disorders, anxiety disorders, eating disorders, externalizing disorders, and personality disorders (PDs) other than schizotypal yielded little persuasive evidence of taxa. Promising but still not definitive evidence of psychological taxa was confined to the domains of schizotypy, substance use disorders and autism. This review indicates that most latent variables of interest to psychiatrists and personality and clinical psychologists are dimensional, and that many influential taxonic findings of early taxometric research are likely to be spurious.
Magnetic fabric and tectonic setting of the Early to Middle Jurassic felsic dykes at Pitt Point and Mount Reece, eastern Graham Land, Antarctica
Authors: Žák Jiří , Soejono Igor , Janoušek Vojtěch , Venera Zdeněk
Published: September 2011

At Pitt Point, the east coast of Graham Land (Antarctic Peninsula), the Early to Middle Jurassic (Toarcian–Aalenian) rhyolite dykes form two coevally emplaced NNE–SSW and E–W trending sets. The nearly perpendicular dyke sets define a large-scale chocolate-tablet structure, implying biaxial principal extension in the WNW–ESE and N–S directions. Along the nearby north-eastern slope of Mount Reece, the WNW–ESE set locally dominates suggesting variations in the direction and amount of extension. Magnetic fabric in the dykes, revealed using the anisotropy of magnetic susceptibility (AMS) method, indicates dip-parallel to dip-oblique (?upward) magma flow. The dykes are interpreted as representing sub-volcanic feeder zones above a felsic magma source. The dyke emplacement was synchronous with the initial stages of the Weddell Sea opening during Gondwana break-up, but it remains unclear whether it was driven by regional stress field, local stress field above a larger plutonic body, or by an interaction of both.
The geochemistry of upland ponds, Taylor Valley, Antarctica
Authors: Lyons W. Berry , Welch Kathleen A. , Gardner Christopher B. , Jaros Chris , Moorhead Daryl L. , Knoepfle Jennifer L. , Doran Peter T.
Published: September 2011

The McMurdo Dry Valleys of Antarctica are the largest ice-free region on the continent. These valleys contain numerous water bodies that receive seasonal melt from glaciers. For forty years, research emphasis has been placed on the larger water bodies, the permanent ice-covered lakes. We present results from the first study describing the geochemistry of ponds in the higher elevations of Taylor Valley. Unlike the lakes at lower elevations, the landscape on which these ponds lie is among the oldest in Taylor Valley. These upland ponds wax and wane in size depending on the local climatic conditions, and their ionic concentrations and isotopic composition vary annually depending on the amount of meltwater generated and their hydrologic connectivity. This study evaluates the impact of changes in summer climate on the chemistry of these ponds. Although pond chemistry reflects the initial meltwater chemistry, dissolution and chemical weathering within the stream channels, and possibly permafrost fluid input, the primary control is the dilution effect of glacier melt during warmer summers. These processes lead to differences in solute concentrations and ionic ratios between ponds, despite their nearby proximity. The change in size of these ponds over time has important consequences on their geochemical behaviour and potential to provide water and solutes to the subsurface.
Internal Structure of the Spanish Adaptation of the Eating Disorder Inventory-3
Authors: Elosua Paula , López-Jáuregui Alicia
Published: September 2011

In this study the Eating Disorder Inventory-3 was adapted to Spanish and analyzed the internal psychometric properties of the test in a clinical sample of females with eating disorders. The results showed a high internal consistency of the scores as well as high temporal stability. The factor structure of the scale composites was analyzed using confirmatory factor analysis. The results supported the existence of a second-order structure beyond the psychological composites. The second-order factor showed high correlation with the factor related to eating disorders. Overall, the Spanish version of the EDI-3 showed good psychometric qualities in terms of internal consistency, temporal stability and internal structure.
Psychometric Properties of the Pain Self-Efficacy Questionnaire (PSEQ)
Authors: van der Maas Lia C. C. , de Vet Henrica C. W. , Köke Albère , Bosscher Ruud J. , Peters Madelon L.
Published: September 2011

Self-efficacy beliefs are an important psychosocial determinant of pain behavior and predict the outcome of pain management programs. Participants in these programs are challenged to live a life as normal as possible despite the pain. In view of the continuous presence of pain, self-efficacy measurement should take this into account. The Pain Self-Efficacy Questionnaire (PSEQ) asks participants to take the pain into account when rating their self-efficacy beliefs. In the present study, this questionnaire is examined on its psychometric qualities. The study also examines self-efficacy as an independent predictor of outcome measures after controlling for pain intensity. 278 chronic pain patients participate in this study, divided into two samples. Exploratory and confirmatory factor analysis supported a 1-factor solution. Internal consistency was excellent, and test-retest reliability was adequate. Regression analysis showed that pain self-efficacy was an independent predictor of disability and quality of life after controlling for pain intensity. Furthermore, the PSEQ discriminated between workers and nonworkers, and between patients who used medication and those who did not.
A fast 2‐D parallel multilevel fast multipole algorithm solver for oblique plane wave incidence
Authors: Fostier Jan , Michiels Bart , Bogaert Ignace , De Zutter Daniël
Published: September 2011

We present a multilevel fast multipole algorithm (MLFMA) implementation to numerically solve Maxwell's equations for large two‐dimensional geometries illuminated by an arbitrary plane wave in three‐dimensional space. The solver's capabilities are augmented by means of an asynchronous and hierarchical parallelization. Its accuracy is demonstrated by comparing the analytical and numerically obtained scattering width of several canonical examples with a size of 700,000 wavelengths.
Elements of a flexible approach for conceptual hydrological modeling: 1. Motivation and theoretical development
Authors: Fenicia Fabrizio , Kavetski Dmitri , Savenije Hubert H. G.
Published: September 2011

This paper introduces a flexible framework for conceptual hydrological modeling, with two related objectives: (1) generalize and systematize the currently fragmented field of conceptual models and (2) provide a robust platform for understanding and modeling hydrological systems. In contrast to currently dominant “fixed” model applications, the flexible framework proposed here allows the hydrologist to hypothesize, build, and test different model structures using combinations of generic components. This is particularly useful for conceptual modeling at the catchment scale, where limitations in process understanding and data availability remain major research and operational challenges. The formulation of the model architecture and individual components to represent distinct aspects of catchment‐scale function, such as storage, release, and transmission of water, is discussed. Several numerical strategies for implementing the model equations within a computationally robust framework are also presented. In the companion paper, the potential of the flexible framework is examined with respect to supporting more systematic and stringent hypothesis testing, for characterizing catchment diversity, and, more generally, for aiding progress toward more unified hydrological theory at the catchment scale.
Lunar tides in Loch Ness, Scotland
Authors: Pugh David T. , Woodworth Philip L. , Bos Machiel S.
Published: September 2011

Measurements have been made of the astronomical tide in Loch Ness, Scotland, which is not directly connected to marine tides. Our measurements of the loch tide are, so far as we know, the first in a European lake where the tide originates primarily from ocean tide loading. Loch Ness is a readily accessible lake and is in a region for which the neighboring ocean tides are large and described well by modern global ocean tide models. The principal tidal constituent, M2, was observed to have an amplitude of approximately 1.5 mm, and to be in antiphase, at each end of the loch. These values are in close agreement with the theoretical combined effects of the direct gravitational tide (body tide) and the tilt effects due to ocean tide loading, computed using Green's functions based on conventional elastic‐Earth models. By analyzing over long periods for coherent tidal signals, we are able to significantly improve the signal‐to‐noise ratio in the tilt values compared with values obtained by direct level differencing. Our tilt accuracy of better than 10−8, measured over 35 km, demonstrates Loch Ness as one the world's longest and most accurate tiltmeters. Despite this unprecedented accuracy, Earth tidal models are still at least as accurate as our ability to measure them.
Metabolic signals regulate SIRT1 expression
Authors: Chalkiadaki Angeliki , Guarente Leonard
Published: September 2011

SIRT1 is a key metabolic regulator in response to nutrient availability. Here, Chalkiadaki and Guarente comment on a report published online this month in which J. Auwerx and colleagues show how SIRT1 transcription is controlled by the antagonistic actions of CREB and ChREBP in response to the energetic status of the cell.
Synthesis of poly(p-phenylene vinylene) materials via the precursor routes
Authors: Junkers Tanja , Vandenbergh Joke , Adriaensens Peter , Lutsen Laurence , Vanderzande Dirk
Published: September 2011

The precursor routes to obtain high-molecular weight poly(p-phenylene vinylene)s (PPVs) are reviewed with respect to their applicability towards specific synthesis goals and materials as well as their structural integrity.
Optofluidic characterization of marine algae using a microflow cytometer
Authors: Hashemi Nastaran , Erickson Jeffrey S. , Golden Joel P. , Ligler Frances S.
Published: September 2011

The effects of global warming, pollution in river effluents, and changing ocean currents can be studied by characterizing variations in phytoplankton populations. We demonstrate the design and fabrication of a Microflow Cytometer for characterization of phytoplankton. Guided by chevron-shaped grooves on the top and bottom of a microfluidic channel, two symmetric sheath streams wrap around a central sample stream and hydrodynamically focus it in the center of the channel. The lasers are carefully chosen to provide excitation light close to the maximum absorbance wavelengths for the intrinsic fluorophores chlorophyll and phycoerythrin, and the excitation light is coupled to the flow cytometer through the use of an optical fiber. Fluorescence and light scatter are collected using two multimode optical fibers placed at 90-degree angles with respect to the excitation fiber. Light emerging from these collection fibers is directed through optical bandpass filters into photomultiplier tubes. The cytometer measured the optical and side scatter properties of Karenia b., Synechococcus sp., Pseudo-Nitzchia, and Alexandrium. The effect of the sheath-to-sample flow-rate ratio on the light scatter and fluorescence of these marine microorganisms was investigated. Reducing the sample flow rate from 200 μL/min to 10 μL/min produced a more tightly focused sample stream and less heterogeneous signals.
Nanofiber-modified surface directed cell migration and orientation in microsystem
Authors: Zhang Xu , Gao Xinghua , Jiang Lei , Zhang Xulang , Qin Jianhua
Published: September 2011

Cell-microscale pattern surface interactions are crucial to understand many fundamental biological questions and develop regenerative medicine and tissue engineering approaches. In this work, we demonstrated a simple method to pattern PDMS surface by sacrificing poly vinyl pyrrolidone (PVP) electrospinning nanofibers and investigated the growth profile of cells on the modified patterned surfaces using stroma cells. The stromal cells were observed to exhibit good viability on this modified surface and the patterned surface with alignment nanofibers could promote cell migration. Furthermore, the modified PDMS surface was integrated with microfluidic channels to create the microscale spatial factor and was used to explore the cell migration and orientation under this microsystem. Both spatial factor and patterned surfaces were found to contribute to the complex cell orientation under the combined dual effects. This established method is simple, fast, and easy for use, demonstrating the potential of this microsystem for applications in addressing biological questions in complex environment.
Fragmentation of singly charged adenine induced by neutral fluorine beam impact at 3 keV
Authors: Chen L. , Brédy R. , Bernard J. , Montagne G. , Allouche A. R. , Martin S.
Published: September 2011

The fragmentation scheme of singly charged adenine molecule (H5C5N5+) has been studied via neutral fluorine impact at 3 keV. By analyzing in correlation the kinetic energy loss of the scattered projectile F− produced in single charge transfer process and the mass of the charged fragments, the excitation energy distribution of the parent adenine molecular ions has been determined for each of the main dissociation channels. Several fragmentation pathways unrevealed in standard mass spectra or in appearance energy measurements are investigated. Regarding the well-known hydrogen cyanide (HCN) loss sequence, we demonstrate that although the loss of a HCN is the dominant decay channel for the parent H5C5N5+ (m = 135), the decay of the first daughter ion H4C4N4+ (m = 108) involves not only the HNC (m = 27) loss but also the symmetric breakdown into two dimers of HCN.
Residual stresses within oxide layers due to lateral growth strain and creep strain: Analytical modeling
Authors: Maharjan S. , Zhang X. C. , Xuan F. Z. , Wang Z. D. , Tu S. T.
Published: September 2011

Deflection test has been widely used to estimate residual stresses within an oxide layer during isothermal oxidation of one surface of an alloy or metal. Deflection models so far developed have considered elastic, plastic, and creep model to predict stresses produced from curvature of the metal/oxide interface. However, none of the models have considered growth stress. During oxidation, when new oxide forms along grain boundaries lying perpendicular to the interface, it will generate a lateral growth strain. When this strain is constrained by the underlying metal, it will generate growth stress in the oxide. This lateral growth strain combined with creep strain of the both oxide and metal will then provide the realistic approach to deal with stresses in oxide/metal composite. Considering these situations an analytical model has been developed to determine residual stresses for the metal/oxide composite of the deflection test. The stress value in both metal and oxide is calculated for notional mechanical properties. Moreover, the effects of oxide thickness, oxidation time, lateral growth constant, and the creep constants on stresses are discussed.
Near-infrared luminescent and antireflective in SiO2/YVO4:Yb3+ bilayer films for c-Si solar cells
Authors: Peng Yingjie , Liu Jie , Zhang Kun , Luo Hui , Li Jihong , Xu Bo , Han Lixian , Li Xiaojuan , Yu Xibin
Published: September 2011

We demonstrate a facile approach for the architecture of a multifunctional bilayer thin films which show both antireflection and near-infrared (NIR) luminescence. NIR luminescence YVO4:Yb3+ transparent film and nanoporous SiO2 film were successively built on slide glass. Intense NIR emission around 900–1100 nm has been obtained, which is assigned to the electronic transition 2F7/2→2F5/2 of Yb3+, meanwhile, the maximum transmittance reached as high as ∼95%, whereas that of the glass substrate is ∼91%. It is the sought candidate material for c-Si solar cell by downconversion of UV light to NIR photons and increasing photon transmission.
Influence of particle size in hybrid solar cells composed of CdSe nanocrystals and poly(3-hexylthiophene)
Authors: Brandenburg J. E. , Jin X. , Kruszynska M. , Ohland J. , Kolny-Olesiak J. , Riedel I. , Borchert H. , Parisi J.
Published: September 2011

Inorganic semiconductor nanoparticles, such as CdSe quantum dots, are considered to be a promising alternative to fullerene derivates for application as electron acceptors in polymer-based bulk heterojunction solar cells. The main potential advantage is the strong light absorption of CdSe nanoparticles with a spectral bandwidth, which can even be tuned, due to the quantum size effect. However, the impact of the particle size on the performance of polymer/CdSe solar cells has remained largely unexplored so far. Therefore, the influence of particle size in hybrid solar cells using a blend of poly(3-hexylthiophene) (P3HT) and quasi-spherical CdSe nanoparticles on relevant cell parameters and the overall solar cell performance is systematically studied in the present work. As the most important result, an increase of the open-circuit voltage (VOC) can be found for smaller nanoparticles and can be explained by an “effective bandgap” model. In contrast, no significant changes of the short-circuit current density with particle size are observed. Smaller particles were found to yield a lower fill factor, compensating the gain in VOC, so that the power conversion efficiency finally turned out to be independent of the particle size in this study. Spectral differences observed in the respective external quantum efficiency spectra of the solar cells can be attributed to size-dependent changes of the particle absorption. Temperature-dependent measurements of the current-voltage (I-V) characteristics suggest that the transport of photogenerated charge carriers in the bulk heterojunction is limited by localized states, with activation energy beyond thermal energy at room temperature.
Light-induced change in magnetization-induced second harmonic generation of Fe0.52Rh0.48 films
Authors: Nuida Tomohiro , Yamauchi Takahiro , Ohkoshi Shin-ichi
Published: September 2011

Irradiating with pulsed laser light induces high-speed optical switching of surface magnetization-induced second harmonic generation (MSHG) in Fe0.52Rh0.48 thin films at room temperature. The second harmonic rotation angle (θSH) of 25.0° was recorded in the irradiated film at 2000 Oe. This θSH value is as much as 740 times larger than the normal Kerr rotation angle (0.034° at 388 nm). The observed gigantic θSH value is attributed to surface MSHG on the ferromagnetic phase in Fe0.52Rh0.48, which is generated by the optical heating.
Understanding the anomalous conductance plateau in asymmetrically biased InAs/In0.52Al0.48As quantum point contacts—A step towards a tunable all electric spin valve
Authors: Das P. P. , Chetry K. B. , Bhandari N. , Wan J. , Cahay M. , Newrock R. S. , Herbert S. T.
Published: September 2011

The appearance and evolution of an anomalous conductance plateau at 0.4(2e2/h) in an In0.52Al0.48As/InAs quantum point contact (QPC), in the presence of lateral spin-orbit coupling, has been studied at T = 4.2 K as a function of the potential asymmetry between the in-plane gates of the QPC. The anomalous plateau, a signature of spin polarization in the channel, appears only over an intermediate range (around 3 V) of bias asymmetry. It is quite robust, being observed over a maximum range of nearly 1 V of the sweep voltage common to the two in-plane gates. The conductance measurements show evidence of surface roughness and dangling bond scattering from the side walls of the QPC.
Low density mesostructures of confined dipolar particles in an external field
Authors: Richardi J. , Weis J.-J.
Published: September 2011

Mesostructures formed by dipolar particles confined between two parallel walls and subjected to an external field are studied by Monte Carlo simulations. The main focus of the work is the structural behavior of the Stockmayer fluid in the low density regime. The dependence of cluster thickness and ordering is estimated as a function of density and wall separation, the two most influential parameters, for large dipole moments and high field strengths. The great sensitivity of the structure to details of the short-range part of the interactions is pointed out. In particular, the attractive part of the Lennard-Jones potential is shown to play a major role in driving chain aggregation. The effect of confinement, evaluated by comparison with results for a bulk system, is most pronounced for a short range hard sphere potential. No evidence is found for a novel “gel-like” phase recently uncovered in low density dipolar colloidal suspensions [A. K. Agarwal and A. Yethiraj, Phys. Rev. Lett. 102, 198301 (2009)10.1103/PhysRevLett.102.198301].
Configuration and temperature dependence of magnetic damping in spin valves
Authors: Joyeux X. , Devolder T. , Kim Joo-Von , Gomez de la Torre Y. , Eimer S. , Chappert C.
Published: September 2011

Using vector-analyzer ferromagnetic resonance, we have studied the microwave susceptibility of a Py/Co/Cu/Co/MnIr spin valve over a large temperature range (5-450 K) and as a function of the magnetic configuration. An effective magnetization and Gilbert damping constant of 1.1 T and 0.021, respectively, are found for the permalloy free layer, with no discernible variation in temperature observed for either quantities. In contrast, the pinned layer magnetization is reduced by heating, and the exchange bias collapses near a temperature of 450 K. The ferromagnetic resonance linewidth of the free layer increases by 500 MHz when the layer magnetizations are aligned in antiparallel, which is attributed to a configuration-dependent contribution to the damping from spin pumping effects.
High-pressure equation of state properties of bismuth oxide
Authors: Fredenburg D. A. , Thadhani N. N.
Published: September 2011

The high pressure equation of state response of hot pressed bismuth trioxide (Bi2O3) powder compacts is determined through a series of parallel plate impact gas-gun experiments. Loose powders of Bi2O3 are hot-pressed to an average density of 9.202 g/cm3, corresponding to 96% theoretical maximum density. Shock compaction of the compacts to pressures between 4-17 GPa reveal full consolidation occurring at pressures above ∼ 8 GPa. Using the experimentally determined Hugoniot of the 96% dense compact, calculations are performed to obtain the equation of state parameters for solid density Bi2O3.
Structure, magnetic and dielectric properties in Mn-substituted Sm1.5Sr0.5NiO4 ceramics
Authors: Wen Jia Bo , Qiang Liu Xiao , Ming Chen Xiang
Published: September 2011

The crystal structures, magnetic and dielectric properties were evaluated for Sm1.5Sr0.5Ni1-xMnxO4 (x = 0.03, 0.05, 0.1) ceramics. The Rietveld results of X-ray diffraction patterns confirmed single orthorhombic phase with the space group of Bmab (64) were obtained in Sm1.5Sr0.5Ni1-xMnxO4 (x = 0.03, 0.05) ceramics, while in Sm1.5Sr0.5Ni0.9Mn0.1O4 ceramics, apart from the main orthorhombic phase, a tiny secondary phase was detected. A magnetism characteristic of a spin glass was found in Sm1.5Sr0.5NiO4, while a complicated magnetic phenomenon was observed in Sm1.5Sr0.5Ni0.9Mn0.1O4 ceramics. The giant dielectric response was observed in these ceramics, and dielectric loss decreased with increasing the content of manganese ions. After comparing the activation energies of dielectric relaxation and electrical conduction, the low-temperature giant dielectric response should be attributed to the adiabatic small polaronic hopping process, while at high-temperature, the low frequency relaxation was mainly attributed to the grain boundary effect. The suppression of dielectric loss should be benefited from the various polar region caused by Mn-substitution.
A tilt sensor with a compact dimension based on a long-period fiber grating
Authors: Wang Yunpeng , Zhao Chun-Liu , Hu Limin , Dong Xinyong , Jin Yongxing , Shen Changyu , Jin Shangzhong
Published: September 2011

A tilt sensor with a compact dimension based on a long-period fiber grating (LPG) is proposed and experimentally demonstrated. The LPG is fixed in a rigid Plexi-glass tubular with a slant orientation and half of the LPG is immersed into the NaCl aqueous solutions, whereas the other half is exposed in air. The tilt angle is obtained by monitoring the dip wavelength shift of the LPG, which changes gradually when the immersed length of the LPG varies with the tilt angle. Experimental results show that the average sensitivity 0.077 nm/° is achieved within the measurement range from −30º to 30º at the static measurement.
Thermally induced currents in graphene-based heterostructure
Authors: Zeng Minggang , Feng Yuanping , Liang Gengchiau
Published: September 2011

We investigate thermally induced currents in a zigzag graphene nanoribbon (ZGNR) heterostructure, consisting of hydrogen-terminated ZGNR (ZGNR-H) and oxygen-terminated ZGNR (ZGNR-O), under different electronic and magnetic states. Compared to a pure ZGNR-H system, the heterostructure displays a considerably larger thermally induced current due to its asymmetric transmission spectrum. Moreover, the magnetized ZGNR-H/ZGNR-O shows spin filter and magnetoresistance effects, suggesting potential applications of the ZGNR-H/ZGNR-O heterostructures in thermoelectric and spintronics devices.
Effect of ZnO nanoparticles on the SmC*-SmA* phase transition temperature in electroclinic liquid crystals
Authors: Malik A. , Choudhary A. , Silotia P. , Biradar A. M.
Published: September 2011

ZnO nanoparticles (NPs), synthesized in an alcoholic medium at room temperature, were added to electroclinic liquid crystal (ELC) materials. The addition of ZnO NPs in ELCs, caused a remarkable shift in SmC*-SmA* phase transition which was investigated from the dielectric and electro-optical measurements. The anchoring of ELC molecules around ZnO NPs creates orientational distortions near the surface, which may give additional ordering to the ELC molecular arrangement. After analyzing collective dielectric relaxation processes of ZnO NP doped ELCs, three distinct loss peaks were observed. The different behavior of ZnO NP doped ELC from pure ELC has been explained by determining the dielectric strength, the distribution parameter and the corresponding relaxation frequency, and so on, and then these results have been compared with the data calculated by using the theoretical model. The effect of ZnO NPs addition on physical parameters, such as spontaneous polarization (Ps) and rotational viscosity (η) has also been observed.
Combining x-ray and photoacoustics for in vivo tumor imaging with gold nanorods
Authors: Huang Guojia , Yang Sihua , Yuan Yi , Xing Da
Published: September 2011

We have demonstrated a new hybrid cancer imaging method combining x-ray and photoacoustic imaging with multifunctional gold nanorods as contrast agents. The two imaging modalities provide complementary contrast mechanisms. X-ray imaging exploits the high attenuation coefficient of gold nanorods, while photoacoustic imaging takes advantage of the strong optical absorption of the nanorods. The fused image has presented both location and vasculature of the tumor. Our experimental results demonstrate that this combined modality has the capability to provide anatomical and functional information of tumor for accurate medical diagnosis and imaging-guided therapy.
Undistorted 3D microstructures in SU8 formed through two-photon polymerization
Authors: Ohlinger Kris , Lin Yuankun , Poole Zsolt , Chen Kevin P.
Published: September 2011

This paper presents the wavelength dependence of two-photon polymerization in SU-8 between 720-780 nm. The study is performed by microstructuring SU-8 through a single-shot exposure of SU-8 to 140 fs tunable laser pulses with 80 MHz repetition rate, or by laser direct writing. Two-photon absorption is closely related to one-photon absorption in pristine SU-8. By careful design of the neighboring micro-structures, or by varying wet-processing parameters during development, undistorted and unbended 3D micro-structures have been fabricated through direct laser writing.
Measurement of group velocity dispersion of solvents using 2-cycle femtosecond pulses: Experiment and theory
Authors: Devi Pampa , Lozovoy Vadim V. , Dantus Marcos
Published: September 2011

Second and third-order dispersion for water, methanol, cyclohexane, carbon tetrachloride, dimethyl sulfoxide, toluene and carbon disulfide are measured with high accuracy and precision in the range of 700-900 nm using two-cycle long femtosecond laser pulses. The ratio between second and third-order dispersion, which is predicted to vary linearly, is experimentally confirmed and this observation is examined theoretically. A method to predict second and third-order dispersion of unknown transparent media with accuracy that is comparable to the best experimental methods is proposed and tested. The information provided is important for applications of ultrafast lasers in science, medicine and industry.
Paper Productivity of Ground-based Large Optical Telescopes from 2000 to 2009
Authors: Kim Sang Chul
Published: September 2011

We present an analysis of the scientific (refereed) paper productivity of the current largest (diameter > 8m) ground-based optical (and infrared) telescopes during the ten-year period from 2000 to 2009. The telescopes for which we have gathered and analysed the scientific publication data are the two 10-m Keck telescopes, the four 8.2-m Very Large Telescopes (VLT), the two 8.1-m Gemini telescopes, the 8.2-m Subaru telescope, and the 9.2-m Hobby–Eberly Telescope (HET). We have analysed the numbers of papers published in various astronomical journals produced by using these telescopes. While the total numbers of papers from these observatories are largest for the VLT, followed by Keck, Gemini, Subaru, and HET, the number of papers produced by each component of the telescopes is largest for Keck, followed by VLT, Subaru, Gemini, and HET. In 2009, each telescope of the Keck, VLT, Gemini, Subaru, and HET observatories produced 135, 109, 93, 107, and 5 refereed papers, respectively. We have shown that each telescope of the Keck, VLT, Gemini, and Subaru observatories is producing 2.1 ± 0.9 Nature and Science papers annually and these papers make up 1.7 ± 0.8% of all refereed papers produced by using each of those telescopes. Extending this relation, we propose that this ratio of the number of Nature and Science papers to the total number of refereed papers that will be produced by future extremely large telescopes (ELTs) will remain similar. From a comparison of the publication trends of the above telescopes, we suggest that (i) having more than one telescope of the same kind at the same location and (ii) increasing the number of instruments available at the telescope are good ways to maximize the paper productivity.
A Next Generation Deep 2-μm Survey: Reconnoitering the Dark Ages
Authors: Mould Jeremy
Published: September 2011

The next generation 2-μm sky survey should target nascent galaxies in the epoch of reionization for spectroscopic followup on large telescopes. A 2.5-m telescope at a site on the Antarctic plateau has advantages for this purpose and for southern hemisphere infrared surveys in general.
Conformation of self-assembled porphyrin dimers in liposome vesicles by phase-modulation 2D fluorescence spectroscopy
Authors: Lott Geoffrey A. , Perdomo-Ortiz Alejandro , Utterback James K. , Widom Julia R. , Aspuru-Guzik Alán , Marcus Andrew H.
Published: September 2011

By applying a phase-modulation fluorescence approach to 2D electronic spectroscopy, we studied the conformation-dependent exciton coupling of a porphyrin dimer embedded in a phospholipid bilayer membrane. Our measurements specify the relative angle and separation between interacting electronic transition dipole moments and thus provide a detailed characterization of dimer conformation. Phase-modulation 2D fluorescence spectroscopy (PM-2D FS) produces 2D spectra with distinct optical features, similar to those obtained using 2D photon-echo spectroscopy. Specifically, we studied magnesium meso tetraphenylporphyrin dimers, which form in the amphiphilic regions of 1,2-distearoyl-sn-glycero-3-phosphocholine liposomes. Comparison between experimental and simulated spectra show that although a wide range of dimer conformations can be inferred by either the linear absorption spectrum or the 2D spectrum alone, consideration of both types of spectra constrain the possible structures to a “T-shaped” geometry. These experiments establish the PM-2D FS method as an effective approach to elucidate chromophore dimer conformation.
Similarities between long interspersed element-1 (LINE-1) reverse transcriptase and telomerase
Authors: Kopera Huira C. , Moldovan John B. , Morrish Tammy A. , Garcia-Perez Jose Luis , Moran John V.
Published: September 2011

Long interspersed element-1 (LINE-1 or L1) retrotransposons encode two proteins (ORF1p and ORF2p) that contain activities required for conventional retrotransposition by a mechanism termed target-site primed reverse transcription. Previous experiments in XRCC4 or DNA protein kinase catalytic subunit-deficient CHO cell lines, which are defective for the nonhomologous end-joining DNA repair pathway, revealed an alternative endonuclease-independent (ENi) pathway for L1 retrotransposition. Interestingly, some ENi retrotransposition events in DNA protein kinase catalytic subunit-deficient cells are targeted to dysfunctional telomeres. Here we used an in vitro assay to detect L1 reverse transcriptase activity to demonstrate that wild-type or endonuclease-defective L1 ribonucleoprotein particles can use oligonucleotide adapters that mimic telomeric ends as primers to initiate the reverse transcription of L1 mRNA. Importantly, these ribonucleoprotein particles also contain a nuclease activity that can process the oligonucleotide adapters before the initiation of reverse transcription. Finally, we demonstrate that ORF1p is not strictly required for ENi retrotransposition at dysfunctional telomeres. Thus, these data further highlight similarities between the mechanism of ENi L1 retrotransposition and telomerase.
National Self-Determination and Soviet Denouement
Authors: Gleason Gregory
Published: September 2011

On the theatrical stage, the term “dénouement“ refers to the resolution of a dramatic complication. On the stage of world events, few historical periods can rival the present situation in the Soviet successor states for satisfying this definition more exactly. On December 21, 1991, eleven men—all, ironically, former communist party officials—signed an agreement in Alma-Ata, Kazakhastan, resolving that the Union of Soviet Socialist Republics “henceforth will cease to exist.” With this announcement, the “Soviet experiment” came to an end and a new world, inchoate and uncertain, began to emerge.
The Migration of Russians Outside Their Homeland
Authors: Lewis Robert A.
Published: September 2011

The migration and settlement of Russians throughout the former Soviet Union in combination with rising nationalism have resulted in a set of conditions that will probably result in considerable national conflict. From an operational perspective, the subjective definition of a nation is the most useful. A nation is a self-defining community whose members claim a common ancestry and a common destiny. They also claim a common geographic origin, the national homeland, over which they claim an exclusive, proprietary right. In fact, nations seek to ensure their destiny by controlling the national homeland for the benefit of their nation, and by promoting the indigeneous nation to a dominant, preferential position. A primordial connection between nation and homeland—blood and soil—is claimed, which results in a geographic or spatial identity, imbued with great emotion as the sacred ancestral land. The national homeland is delimited and justified by either history, demography, or both. Although demographic dominance can generally be claimed by only one nation, the historical claim can be made by more than one, and frequently the demographic claim is reinforced by the historical argument. Most national and ethnic conflict is provoked by conflicting claims to the homeland or aliens residing in the national homeland. Thus, as a rule, the more ethnically homogeneous the homeland, the less the conflict among nations. Of course, this is not always the case. A major national goal is ethnic homogeneity in the national homeland, as various restrictive language, citizenship, and immigration laws demonstrate. Yet this aim will not be sought at the expense of control over ancestral territory.