bluuebunny/crossref_metadata_2025 huggingface dataset:
Microscopic interpretation of sign reversal in the electrocaloric effect in a ferroelectric PbMg1/3Nb2/3O3-30PbTiO3 single crystal
Authors: Axelsson A.-K. , Le Goupil F. , Dunne L. J. , Manos G. , Valant M. , Alford N. McN.
Published: March 2013

With increasing temperature, PbMg1/3Nb2/3O3-30PbTiO3 (PMN-30PT) crystals change from pseudo-rhombohedral to tetragonal to cubic phases. In addition to the usual positive electrocaloric effect (ECE), a negative ECE, whose origin is uncertain, is observed. Here, these two types of the ECE contributions in PbMg1/3Nb2/3O3-30PbTiO3 crystals are modelled theoretically using a one dimensional statistical mechanical lattice model, which is solved by an exact matrix method. The quasi one-dimensional model reproduces the trends in the experimental behaviour and attributes the electrocaloric sign reversal to free energy changes induced by the electric field.
Thermal neutron detection using a silicon pad detector and 6LiF removable converters
Authors: Barbagallo Massimo , Cosentino Luigi , Forcina Vittorio , Marchetta Carmelo , Pappalardo Alfio , Peerani Paolo , Scirè Carlotta , Scirè Sergio , Schillaci Maria , Vaccaro Stefano , Vecchio Gianfranco , Finocchiaro Paolo
Published: March 2013

A semiconductor detector coupled with a neutron converter is a good candidate for neutron detection, especially for its compactness and reliability if compared with other devices, such as 3He tubes, even though its intrinsic efficiency is rather lower. In this paper we show a neutron detector design consisting of a 3 cm × 3 cm silicon pad detector coupled with one or two external 6LiF layers, enriched in 6Li at 95%, placed in contact with the Si active surfaces. This prototype, first characterized and tested at INFN Laboratori Nazionali del Sud and then at JRC Ispra, was successfully shown to detect thermal neutrons with the expected efficiency and an outstanding gamma rejection capability.
Note: Simple calibration of the counting-rate dependence of the timing shift of single photon avalanche diodes by photon interval analysis
Authors: Otosu Takuhiro , Ishii Kunihiko , Tahara Tahei
Published: March 2013

The counting-rate dependence of the temporal response of single photon avalanche diodes (SPADs) is a critical issue for the accurate determination of the fluorescence lifetime. In this study, the response of SPADs was examined with analyzing the time interval of the detected photons. The results clearly show that the shift of the detection timing causes the counting-rate dependence of the temporal response, and this timing shift is solely determined by the time interval from the preceding photon. We demonstrate that this timing instability is readily calibrated by utilizing the macrotime data taken with the time-tag mode that is implemented in the time-correlated single photon counting modules.
Nonlinear dissipation in diamond nanoelectromechanical resonators
Authors: Imboden Matthias , Williams Oliver , Mohanty Pritiraj
Published: March 2013

Dissipation of energy in micro- and nano-electromechanical resonators governs their dynamical response and limits their potential use in device applications. Quantified by the quality factor Q, dissipation (Q−1) usually occurs by energy loss mechanisms that are linear, appearing as a damping term proportional to the velocity. Mechanisms of linear dissipation in micro- and nano-mechanical resonators are well studied both theoretically and experimentally. Mechanisms of nonlinear dissipation of energy, however, are rarely studied, though their effects could be fundamentally important to the operation of numerous devices based on nonlinear resonators such as switches, signal processers, sensors, and energy harvesting systems. Here, we report experimental observation of nonlinear dissipation in diamond nanoelectromechanical resonators.
Design of a vertically coupled liquid-crystal long-range plasmonic optical switch
Authors: Zografopoulos Dimitrios C. , Beccherelli Romeo
Published: March 2013

An optical switch based on liquid-crystal (LC) tunable long-range metal stripe waveguides is proposed and theoretically investigated. A nematic liquid crystal layer placed between a vertical configuration consisting of two gold stripes is shown to allow for the extensive electro-optic tuning of the coupler's waveguiding characteristics. Rigorous liquid-crystal switching studies are coupled with the investigation of the optical properties of the proposed plasmonic structure, taking into account different excitation conditions and the impact of LC-scattering losses. A directional coupler optical switch is demonstrated, which combines low power consumption, low cross-talk, short coupling lengths, along with sufficiently reduced insertion losses.
Symbols and the culture of memory in Republika Srpska Krajina
Authors: Pavlaković Vjeran
Published: March 2013

This article examines how rebel Serbs in Croatia reinterpreted narratives of World War Two to justify their uprising against the democratically elected Croatian government in 1990 and gain domestic and international legitimacy for the Republika Srpska Krajina (RSK) parastate. While scholars have written about the strategies nationalist elites used regarding controversial symbols and the rehabilitation of World War Two collaborators in Croatia and other Yugoslav successor states, the RSK's “culture of memory” has received little attention. Based on documents captured after the RSK's defeat in 1995, this article shows that it was not only the government of Franjo Tudjman that rejected the Partisan narratives of “Brotherhood and Unity,” but a parallel process took place among the leadership in the Krajina. Ultimately the decision to base the historical foundations of the Croatian Serbs’ political goals on a chauvinist and extremist interpretation of the past resulted in a criminalized entity that ended tragically for both Serbs and Croats living on the territory of the RSK.
Kyrgyzstan between democratization and ethnic intolerance
Authors: Wachtel Andrew Baruch
Published: March 2013

The international community has expressed great concern about the treatment of the Uzbek minority in the south of Kyrgyzstan and has called on the majority community to make major efforts to improve the situation. The article compares the treatment of minorities in Kyrgyzstan with analogous situations in the Balkans and contends that, given the European-style ethnonational state model and democratic political system that have been adopted by independent Kyrgyzstan, such calls are unrealistic.
Subnanometer-resolution depth profiling of boron atoms and lattice defects in silicon ultrashallow junctions by ion beam techniques
Authors: Vanamurthy Lakshmanan H. , Huang Mengbing , Bakhru Hassaram , Furukawa Toshiharu , Berliner Nathaniel , Herman Joshua , Zhu Zhengmao , Ronsheim Paul , Doris Bruce
Published: March 2013

The continued research and development effort on silicon ultrashallow junctions has posed a great challenge to materials characterization, due to the need for depth profiling of dopants and silicon lattice defects with a subnanometer resolution. In this work, we report on a method combining ion beam analysis (Rutherford backscattering, ion channeling, and nuclear reaction analysis) with room-temperature UV-assisted oxidation and chemical wet etching for obtaining high-resolution (∼0.5 nm) depth distributions of total boron atoms, electrically activated boron atoms and silicon lattice defects in silicon ultrashallow junctions. The application of this method was demonstrated by profiling silicon junctions as shallow as 8 nm, created by 200-eV boron ion implantation followed annealing by various techniques. The capability to profile boron at such high resolution has resulted in observation of boron segregation. Additionally, the ability for depth profiling Si lattice defects offered by this method has aided in the understanding of thermal and laser annealing effects on defect formation in Si junctions. Our experimental results are compared with those obtained using other techniques such as secondary ion mass spectroscopy and four-point probe, and differences are discussed in detail.
Using the Wii Balance Board in Elevator Physics
Authors: Mullenax Donna
Published: March 2013

The Wii Balance Board is a popular accessory to the wireless video system the Wii. In the past few years, the Wii Remote™ and Wii Balance Board accessories to the Wii have made their way into physics labs as sensors to measure force and acceleration. In most introductory physics courses, the forces experienced while on an elevator are discussed and calculated. The Wii Balance Board is a very good tool for having students measure the forces experienced on an elevator and calculating the acceleration of the elevator when it starts to move and then while it is coming to a stop.
Observing the Forces Involved in Static Friction Under Static Situations
Authors: Kaplan Daniel
Published: March 2013

Static friction is an important concept in introductory physics. Later in the year students apply their understanding of static friction under more complex conditions of static equilibrium. Traditional lab demonstrations in this case involve exceeding of the maximum level of static friction, resulting in the onset of motion.
Mechanical Energy Changes in Perfectly Inelastic Collisions
Authors: Mungan Carl E.
Published: March 2013

Suppose a block of mass m1 traveling at speed v1 makes a one-dimensional perfectly inelastic collision with another block of mass m2. What else does one need to know to calculate the fraction of the mechanical energy that is dissipated in the collision?
Using Charge Distributions to “Immerse” Your Classroom in an Electric Field
Authors: Gaffney Jon D. H. , Richards Evan , Foote Kathleen , Beichner Robert J.
Published: March 2013

Because electric fields are both invisible and three dimensional, they can be quite difficult to introduce to students. Simple diagrams are unable to convey the complexity or depth of the field, and computer simulations in isolation do not provide a familiar spatial context for students to understand what they see. Through “immersing” the classroom in an imaginary electric field, we propose an activity to engage the students in both visualizing and computing the electric field generated by a distribution of charges. This activity provides the opportunity for active learning within classrooms of all sizes, whether they utilize a traditional lecture format or a reformed learning environment.
Taking it to the Streets…and Bridges, Squares, and Castles
Authors: Chiaverina Chris
Published: March 2013

Each May a Slovenian science extravaganza called Znanstival (Sciencetival, www.sciencetival.si) fills the streets and other public venues with the excitement of science. Organized by the staff of Hisa eksperimentov (House of Experiments or simply HE, www.he.si), a jewel of a science museum located in the Slovenian capital of Ljubljana, the annual celebration of science serves as a model of effective science education for the public.
Graphs and Tracks Revisited
Authors: Christian Wolfgang , Belloni Mario
Published: March 2013

We have recently developed a Graphs and Tracks model based on an earlier program by David Trowbridge,1 as shown in Fig. 1. Our model can show position, velocity, acceleration, and energy graphs and can be used for motion-to-graphs exercises. Users set the heights of the track segments, and the model displays the motion of the ball on the track together with position, velocity, and acceleration graphs. This ready-to-run model is available in the ComPADRE OSP Collection at www.compadre.org/osp/items/detail.cfm?ID=12023.
18
O Changes in Foraminifera Carbonates During the Last 10
5
Years in the Mediterranean Sea
Authors: Grazzini C. Vergnaud
Published: March 2013

The Mediterranean response to major climatic events during the Upper Pleistocene could be seen as an integration of the principal phenomena particular to oceans and of regional phenomena peculiar to the Mediterranean Sea. The magnitude of oxygen isotope changes in foraminifera tests suggests that the temperature variations between stadial and interstadial periods could not exceed 11°C and that the correction factor for isotopic changes of waters should be about twice the value used for the oceans, or 2.7 per mil.
Mass Measurement: A Study of Anomalies
Authors: Pontius Paul E.
Published: March 2013

It has always been assumed that the measurement of the difference in mass between two objects would be the same in all laboratories. Recent National Bureau of Standards measurements involving dissimilar objects (effective density ranging from 2.7 to 16.6 grams per cubic centimeter) at a wide variety of pressures (0.5 to 2 atmospheres) have been made with sufficient precision to test this assumption. The results show unsuspected discrepancies which may approach 1 milligram in a kilogram in the assignment of mass values when dissimilar materials are involved. These discrepancies have not been noted in the past because precision comparisons of both like and unlike materials have nearly always been made in a relatively restricted range of environmental conditions. The worldwide mass measurement system is therefore consistent, because similar materials have been used in the construction of weight sets, but possibly offset with respect to the mass unit as embodied in the platinum-iridium defining artifact.
Charging for Radioactive Emissions
Authors: Wilson Richard
Published: March 2013

Radioactive emissions from nuclear power plants can be controlled by using a pollution charge. This is a more effective and simpler procedure than the present method of shutting down plants and leads to a more desirable balance between alternative sources of energy.
Asteroid Collisional Evolution: Evidence for a Much Larger Early Population
Authors: Chapman Clark R. , Davis Donald R.
Published: March 2013

The present population of asteroids is a remnant of a vastly larger one that contained perhaps a planetary mass, dominantly distributed in planetesimals approximately 500 kilometers or less in diameter. It constituted a large reservoir of objects that plausibly were responsible for cratering the moon, Mars, and Mercury. Much asteroidal dust may have accumulated on Mars and other planets.
Laser-Excited Raman Spectroscopy for Nondestructive Partial Analysis of Individual Phases in Fluid Inclusions in Minerals
Authors: Rosasco Gregory J. , Roedder Edwin , Simmons Joseph H.
Published: March 2013

Laser-excited Raman spectroscopy has been successfully applied to the identification and partial analysis of solid, liquid, and gaseous phases in fluid inclusions. The procedure is no panacea for problems of analysis of fluid inclusions, but some unique features make it very useful. In particular, the measurement is performed in situ; it is nondestructive; and it can produce qualitative and quantitative data, some of which cannot be obtained otherwise, for samples as small as 10
-9
gram.
The Flowers Found with Shanidar IV, a Neanderthal Burial in Iraq
Authors: Leroi-Gourhan Arlette
Published: March 2013

Analysis of soil samples from the Shanidar IV burial, Shanidar cave, revealed the same pollens throughout the sequence, with variations in frequency. However, samples 313 and 314 contained, in addition, several pollen clusters of as many as 100 pollen grains, evidence that complete flowers were introduced into the burial cave.
Magnetotelluric Sounding of Permafrost
Authors: Koziar Andrew , Strangway D. W.
Published: March 2013

The audio-frequency magnetotelluric method was used to sound a permafrost region in the Mackenzie delta in the Northwest Territories. A simple two-layer model consisting of a high electrical resistivity layer overlying less resistive material gave interpreted depths in agreement with those determined by drilling. The summer active layer was transparent even at high sounding frequencies.
Transmission of Creutzfeldt-Jakob Disease from Man to the Guinea Pig
Authors: Manuelidis Elias E.
Published: March 2013

Intracerebral and intraperitoneal inoculation of two guinea pigs with biopsy material from a patient with Creutzfeldt-Jakob disease produced a similar fatal encephalopathy characterized by status spongiosus 422 and 512 days after inoculation. Serial transmission of this disease from guinea pig to guinea pig was achieved in subsequent passages.
Atmospheric Concentrations and Inventory of Krypton-85 in 1973
Authors: Telegadas K. , Ferber G. J.
Published: March 2013

Measurements of the concentrations of
85
Kr in the atmosphere were made in 1973 between 1.5 and 20 kilometers. The global inventory of
85
Kr for 1973 calculated from these data is 53 megacuries. The stratospheric distribution of
85
Kr concentrations shows a maximum in the lower equatorial region of each hemisphere and a minimum concentration in the polar regions. This distribution tends to confirm the mean stratospheric circulation as deduced from other radioactive tracer data. Both
85
Kr and Fluorocarbon-11 (CCl
3
F, here designated as F-11) are inert gases released principally into the surface air in the temperate latitudes of the Northern Hemisphere. The stratospheric distribution of
85
Kr is very similar to that of F-11. Above 20 kilometers a photodissociation of fluorocarbons may take place, producing atomic chlorine which may act as a catalyst in the destruction of stratospheric ozone. Since
85
Kr has no known significant sinks and its half-life is known, measurements of the concentration of both of these gases above 20 kilometers may provide insight regarding the rate of dissociation of F-11.
Stratospheric Ozone: The Possible Effects of Tropospheric-Stratospheric Feedback
Authors: Chameides William L. , Walker James C. G.
Published: March 2013

The existence of tropospheric-stratospheric feedback mechanisms affecting variations in stratospheric ozone indicates the need to model the complete tropospheric-stratospheric system. For instance, a decrease in stratospheric ozone results in increased photolytic destruction of nitrous oxide in the troposphere and thereby reduced production of nitric oxide in the stratosphere. Estimates indicate that this mechanism will result in a recovery in atmospheric ozone of about 6 to 13 percent of the initial perturbation.
Large-Scale Isolation of Intact Vacuoles and Isolation of Chloroplasts from Protoplasts of Mature Plant Tissues
Authors: Wagner George J. , Siegelman H. W.
Published: March 2013

Intact plant vacuoles were prepared in large numbers (10
6
) from protoplasts of mature leaves, flower petals, stems, pedicels, filaments, styles, and young fruits. Treatment of protoplasts with 0.2 molar K
2
HPO
4
-HCl,
p
H 8, with slow stirring resulted in gentle osmotic rupture of the protoplasts and release of intact vacuoles. Particulate components of the protoplast, less the vacuole, were largely shed as an aggregate, which was removed by filtration. Vacuoles were recovered from the filtrate by low-speed centrifugation. The general procedure was also used to isolate chloroplasts with a high degree of integrity and excellent photochemical activity.
Validation of jump squats as a practical measure of post-activation potentiation
Authors: Nibali Maria L. , Chapman Dale W. , Robergs Robert A. , Drinkwater Eric J.
Published: March 2013

To determine if post-activation potentiation (PAP) can augment sports performance, it is pertinent that researchers be confident that any enhancement in performance is attributable to the PAP phenomenon. However, obtaining mechanistic measures of PAP in the daily training environment of highly trained athletes is impractical. We sought to validate jump squats as a practical measure with ecological validity to sports performance against a mechanistic measure of PAP. We assessed the evoked muscle twitch properties of the knee extensors and jump squat kinetics of 8 physically trained males in response to a 5-repetition-maximum back squat conditioning stimulus (CS). Evoked muscle twitch, followed by 3 jump squats, was assessed before and at 4, 8, and 12 min post CS. Time intervals were assessed on separate occasions using a Latin square design. Linear regression was used to determine the relationship between post–pre changes in kinetic variables and muscle twitch peak force (Ft) and twitch rate of force development (RFDt). Large correlations were observed for both concentric relative and absolute mean power and Ft (r = 0.50 ± 0.30) and RFDt (r = 0.56 ± 0.27 and r = 0.58 ± 0.26). Concentric rate of force development (RFD) showed moderate correlations with Ft (r = 0.45 ± 0.33) and RFDt (r = 0.49 ± 0.32). Small-to-moderate correlations were observed for a number of kinetic variables (r = −0.42–0.43 ± 0.32–0.38). Jump squat concentric mean power and RFD are valid ecological measures of muscle potentiation, capable of detecting changes in athletic performance in response to the PAP phenomenon.
Interaction of antioxidants and exercise on insulin sensitivity in healthy and prediabetic rats
Authors: Chowdhury Kawshik K. , Legare Dallas J. , Lautt W. Wayne
Published: March 2013

Meal-induced insulin sensitization (MIS) describes the augmented postprandial response to insulin through action of the hepatic insulin sensitizing substance (HISS). HISS-action is impaired in insulin resistance associated with aging and type 2 diabetes, but could be preserved by the antioxidant cocktail SAMEC, along with voluntary exercise. In this study, we tested whether antioxidant supplementation during voluntary training would interact with the effects of exercise on HISS-mediated glucose uptake in healthy and prediabetic rats. The 7-day voluntary running-wheel training was used as an exercise intervention. SAMEC supplementation was provided only during the 7-day training session. The rapid insulin sensitivity test (RIST) was conducted to determine insulin- and HISS-dependent glucose uptake in 14-week-old healthy rats, and sucrose-induced insulin-resistant rats, with or without exercise in the presence or absence of SAMEC supplementation. The postprandial insulin sensitivity was increased by exercise, primarily through enhancement of the HISS-dependent glucose uptake, which remained unaffected by SAMEC. SAMEC supplementation did not either harm or add benefit to the positive effects of exercise on insulin sensitivity in healthy or prediabetic rats. While SAMEC alone was a demonstrated preventive against the progressive loss of HISS action in previous studies, short-term supplementation in this study did not reverse the established disease state.
Influence of predation risk on recruitment and litter intervals in common voles (Microtus arvalis)
Authors: Jochym M. , Halle S.
Published: March 2013

Research on mammals and birds has shown that predation may have indirect effects on prey reproduction. Some of the indirect effects may give prey an adaptive advantage. Females of several vole species respond to the presence of predators from the genus Mustela L., 1758 with suppressed breeding; this response increases females’ chances of survival. However, breeding suppression is observed only in a certain part of the female population; it is unclear whether predation risk affects the remaining females. We investigated this in a capture–mark–recapture experiment on reproductive effort of female common voles (Microtus arvalis (Pallas, 1778)) facing simulated presence of mustelid predators. We measured two parameters: the number of recruits per litter and the litter interval. Compared with control populations, the number of recruits per litter was not affected, but the litter interval was longer in females facing mustelid risk of predation. This indicates that predation risk affects females in a more complex way than originally proposed: it induces breeding suppression in some, but also influences litter frequency in others. Our result suggests that predatory stress deregulates the estrous cycle. Decreased frequency of litters can be a viable antipredatory adaptation in iteroparous organisms.
Transmission electron microscopy and serial reconstructions reveal novel meiotic phenotypes for theahp2mutant ofArabidopsis thaliana
Authors: Pathan Nazia , Stronghill Patti , Hasenkampf Clare
Published: March 2013

We have found novel phenotypes for the previously studied Arabidopsis thaliana (L.) Heynh. meiotic mutant ahp2. These phenotypes were revealed by analysis of reconstructions of normal and ahp2 nuclei that were imaged using transmission electron microscopy. Previous studies of the ahp2 mutant demonstrated that it has a general failure to form synaptonemal complexes, except for the nucleolus organizing regions, and it fails to complete reciprocal genetic exchange. Here, we show that even though the ahp2 chromosome axes have only 5% of the normal amount of synaptonemal complex formation, it nonetheless has slightly more than 40% of the axes involved in close alignment. We also observed two striking nuclear envelope associated abnormalities. Wild type nuclei contain two nucleoli, one nucleolus-like structure, and nuclear envelope associated structures that we refer to as nuclear envelope associated disks. The ahp2 nuclei have the two nucleoli, but they lack the third nucleolus-like structure and instead have a previously uncharacterized structure that spans the nuclear envelope. Additionally, ahp2 meiocytes have nuclear envelope associated disks that are narrower and more numerous (∼2×) than those seen in wild type, and unlike the wild type disks, they are in direct contact with the nuclear envelope.
SCROLLS AND HYPERBOLICITY
Authors: CILIBERTO C. , ZAIDENBERG M.
Published: March 2013

Using degeneration to scrolls, we give an easy proof of non-existence of curves of low genera on general surfaces in ℙ3of degree d ≥ 5. We also show that there exist Kobayashi hyperbolic surfaces in ℙ3of degree d = 7 (a result so far unknown), and give a new construction of such surfaces of degree d = 6. Our method yields also some lower bounds for geometric genera of surfaces lying on general hypersurfaces of degree 3d ≥ 15 in ℙ4.
Thresholded Two-Phase Test Sample Representation for Outlier Rejection in Biological Recognition
Authors: Wu Xiang , Wu Ning
Published: March 2013

The two-phase test sample representation (TPTSR) was proposed as a useful classifier for face recognition. However, the TPTSR method is not able to reject the impostor, so it should be modified for real-world applications. This paper introduces a thresholded TPTSR (T-TPTSR) method for complex object recognition with outliers, and two criteria for assessing the performance of outlier rejection and member classification are defined. The performance of the T-TPTSR method is compared with the modified global representation, PCA and LDA methods, respectively. The results show that the T-TPTSR method achieves the best performance among them according to the two criteria.
A Common Fixed Point Theorem in Fuzzy Metric Spaces with Nonlinear Contractive Type Condition Defined Using Φ-Function
Authors: Ješić Siniša N. , Babačev Nataša A. , Nikolić Rale M.
Published: March 2013

This paper is to present a common fixed point theorem for twoR-weakly commuting self-mappings satisfying nonlinear contractive type condition defined using a Φ-function, defined on fuzzy metric spaces. Some comments on previously published results and some examples are given.
Current Status of Pyroprocessing Development at KAERI
Authors: Lee Hansoo , Park Geun-IL , Lee Jae-Won , Kang Kweon-Ho , Hur Jin-Mok , Kim Jeong-Guk , Paek Seungwoo , Kim In-Tae , Cho IL-Je
Published: March 2013

Pyroprocessing technology has been actively developed at Korea Atomic Energy Research Institute (KAERI) to meet the necessity of addressing spent fuel management issue. This technology has advantages over aqueous process such as less proliferation risk, treatment of spent fuel with relatively high heat and radioactivity, and compact equipments. This paper describes the pyroprocessing technology development at KAERI from head-end process to waste treatment. The unit process with various scales has been tested to produce the design data associated with scale-up. Pyroprocess integrated inactive demonstration facility (PRIDE) was constructed at KAERI and it began test operation in 2012. The purpose of PRIDE is to test the process regarding unit process performance, remote operation of equipments, integration of unit processes, scale-up of process, process monitoring, argon environment system operation, and safeguards-related activities. The test of PRIDE will be promising for further pyroprocessing technology development.
Noninvasive Measurement of Conductivity Anisotropy at Larmor Frequency Using MRI
Authors: Lee Joonsung , Song Yizhuang , Choi Narae , Cho Sungmin , Seo Jin Keun , Kim Dong-Hyun
Published: March 2013

Anisotropic electrical properties can be found in biological tissues such as muscles and nerves. Conductivity tensor is a simplified model to express the effective electrical anisotropic information and depends on the imaging resolution. The determination of the conductivity tensor should be based on Ohm's law. In other words, the measurement of partial information of current density and the electric fields should be made. Since the direct measurements of the electric field and the current density are difficult, we use MRI to measure their partial information such as B1 map; it measures circulating current density and circulating electric field. In this work, the ratio of the two circulating fields, termed circulating admittivity, is proposed as measures of the conductivity anisotropy at Larmor frequency. Given eigenvectors of the conductivity tensor, quantitative measurement of the eigenvalues can be achieved from circulating admittivity for special tissue models. Without eigenvectors, qualitative information of anisotropy still can be acquired from circulating admittivity. The limitation of the circulating admittivity is that at least two components of the magnetic fields should be measured to capture anisotropic information.
patGPCR: A Multitemplate Approach for Improving 3D Structure Prediction of Transmembrane Helices of G-Protein-Coupled Receptors
Authors: Wu Hongjie , Lü Qiang , Quan Lijun , Qian Peide , Xia Xiaoyan
Published: March 2013

The structures of the seven transmembrane helices of G-protein-coupled receptors are critically involved in many aspects of these receptors, such as receptor stability, ligand docking, and molecular function. Most of the previous multitemplate approaches have built a “super” template with very little merging of aligned fragments from different templates. Here, we present a parallelized multitemplate approach, patGPCR, to predict the 3D structures of transmembrane helices of G-protein-coupled receptors. patGPCR, which employs a bundle-packing related energy function that extends on the RosettaMem energy, parallelizes eight pipelines for transmembrane helix refinement and exchanges the optimized helix structures from multiple templates. We have investigated the performance of patGPCR on a test set containing eight determined G-protein-coupled receptors. The results indicate that patGPCR improves the TM RMSD of the predicted models by 33.64% on average against a single-template method. Compared with other homology approaches, the best models for five of the eight targets built by patGPCR had a lower TM RMSD than that obtained from SWISS-MODEL; patGPCR also showed lower average TM RMSD than single-template and multiple-template MODELLER.
iTRAQ-Based and Label-Free Proteomics Approaches for Studies of Human Adenovirus Infections
Authors: Trinh Hung V. , Grossmann Jonas , Gehrig Peter , Roschitzki Bernd , Schlapbach Ralph , Greber Urs F. , Hemmi Silvio
Published: March 2013

Both isobaric tags for relative and absolute quantitation (iTRAQ) and label-free methods are widely used for quantitative proteomics. Here, we provide a detailed evaluation of these proteomics approaches based on large datasets from biological samples. iTRAQ-label-based and label-free quantitations were compared using protein lysate samples from noninfected human lung epithelial A549 cells and from cells infected for 24 h with human adenovirus type 3 or type 5. Either iTRAQ-label-based or label-free methods were used, and the resulting samples were analyzed by liquid chromatography (LC) and tandem mass spectrometry (MS/MS). To reduce a possible bias from quantitation software, we applied several software packages for each procedure. ProteinPilot and Scaffold Q+ software were used for iTRAQ-labeled samples, while Progenesis LC-MS and ProgenesisF-T2PQ/T3PQ were employed for label-free analyses.R2correlation coefficients correlated well between two software packages applied to the same datasets with values between 0.48 and 0.78 for iTRAQ-label-based quantitations and 0.5 and 0.86 for label-free quantitations. Analyses of label-free samples showed higher levels of protein up- or downregulation in comparison to iTRAQ-labeled samples. The concentration differences were further evaluated by Western blotting for four downregulated proteins. These data suggested that the label-free method was more accurate than the iTRAQ method.
Random Dynamics of the Stochastic Boussinesq Equations Driven by Lévy Noises
Authors: Huang Jianhua , Li Yuhong , Duan Jinqiao
Published: March 2013

This paper is devoted to the investigation of random dynamics of the stochastic Boussinesq equations driven by Lévy noise. Some fundamental properties of a subordinator Lévy process and the stochastic integral with respect to a Lévy process are discussed, and then the existence, uniqueness, regularity, and the random dynamical system generated by the stochastic Boussinesq equations are established. Finally, some discussions on the global weak solution of the stochastic Boussinesq equations driven by general Lévy noise are also presented.
Optimal Short-Time Acquisition Schemes in High Angular Resolution Diffusion-Weighted Imaging
Authors: Prčkovska V. , Achterberg H. C. , Bastiani M. , Pullens P. , Balmashnova E. , ter Haar Romeny B. M. , Vilanova A. , Roebroeck A.
Published: March 2013

This work investigates the possibilities of applying high-angular-resolution-diffusion-imaging- (HARDI-) based methods in a clinical setting by investigating the performance of non-Gaussian diffusion probability density function (PDF) estimation for a range ofb-values and diffusion gradient direction tables. It does so at realistic SNR levels achievable in limited time on a high-performance 3T system for the whole human brainin vivo. We use both computational simulations andin vivobrain scans to quantify the angular resolution of two selected reconstruction methods: Q-ball imaging and the diffusion orientation transform. We propose a new analytical solution to the ODF derived from the DOT. Both techniques are analytical decomposition approaches that require identical acquisition and modest postprocessing times and, given the proposed modifications of the DOT, can be analyzed in a similar fashion. We find that an optimal HARDI protocol given a stringent time constraint (<10 min) combines a moderateb-value (around 2000 s/mm2) with a relatively low number of acquired directions (>48). Our findings generalize to other methods and additional improvements in MR acquisition techniques.
Barrier Properties and Structural Study of Nanocomposite of HDPE/Montmorillonite Modified with Polyvinylalcohol
Authors: Carrera María C. , Erdmann Eleonora , Destéfanis Hugo A.
Published: March 2013

In this work was studied the permeation of CO2 in films of high‐density polyethylene (HDPE) and organoclay modified with polyvinylalcohol (MMTHDTMA/PVA) obtained from melt blending. Permeation study showed that the incorporation of the modified organoclay generates a significant effect on the barrier properties of HDPE. When a load of 2 wt% of MMTHDTMA/PVA was incorporated in the polymer matrix, the flow of CO2 decreased 43.7% compared to pure polyethylene. The results of TEM showed that clay layers were dispersed in the polymeric matrix, obtaining an exfoliated‐structure nanocomposite. The thermal stability of nanocomposite was significantly enhanced with respect to the pristine HDPE. DSC results showed that the crystallinity was maintained as the pure polymeric matrix. Consequently, the decrease of permeability was attributable only to the effect of tortuosity generated by the dispersion of MMTHDTMA/PVA. Notably the mechanical properties remain equal to those of pure polyethylene, but with an increase in barrier properties to CO2. This procedure allows obtaining nanocomposites of HDPE with a good barrier property to CO2 which would make it competitive in the use of packaging.
Homotopy Analysis Method for Boundary-Value Problem of Turbo Warrant Pricing under Stochastic Volatility
Authors: Wong Hoi Ying , Chiu Mei Choi
Published: March 2013

Turbo warrants are liquidly traded financial derivative securities in over-the-counter and exchange markets in Asia and Europe. The structure of turbo warrants is similar to barrier options, but a lookback rebate will be paid if the barrier is crossed by the underlying asset price. Therefore, the turbo warrant price satisfies a partial differential equation (PDE) with a boundary condition that depends on another boundary-value problem (BVP) of PDE. Due to the highly complicated structure of turbo warrants, their valuation presents a challenging problem in the field of financial mathematics. This paper applies the homotopy analysis method to construct an analytic pricing formula for turbo warrants under stochastic volatility in a PDE framework.
Strong Convergence for HybridS-Iteration Scheme
Authors: Kang Shin Min , Rafiq Arif , Kwun Young Chel
Published: March 2013

We establish a strong convergence for the hybridS-iterative scheme associated with nonexpansive and Lipschitz strongly pseudocontractive mappings in real Banach spaces.
On Period of the Sequence of Fibonacci Polynomials Modulo
Authors: Gültekin İnci , Taşyurdu Yasemin
Published: March 2013

It is shown that the sequence obtained by reducing modulo coefficient and exponent of each Fibonacci polynomials term is periodic. Also if is prime, then sequences of Fibonacci polynomial are compared with Wall numbers of Fibonacci sequences according to modulo . It is found that order of cyclic group generated with matrix is equal to the period of these sequences.
Evaluation of the X-Ray Absorption by Gold Nanoparticles Solutions
Authors: Künzel R. , Okuno E. , Levenhagen R. S. , Umisedo N. K.
Published: March 2013

The increase in the X-ray absorption due to gold nanoparticles was investigated by using aqueous solutions containing gold (Au) nanoparticles. A sample with 15 nm in size nanoparticles and 0.5 mg/mL gold concentration and a distilled water sample were used. Transmitted X-ray beams through the samples were registered with a CdTe detector and with an ionization chamber. Results show an enhancement in the X-ray absorption in the range 20%–6% for beams generated from 20 kV to 120 kV tube voltages, respectively. Results show that the use of gold nanoparticles, even at low concentrations, should result in a significant contrast enhancement for low-energy X-ray beams.
The Laplace-Adomian-Pade Technique for the ENSO Model
Authors: Zeng Yi
Published: March 2013

The Laplace-Adomian-Pade method is used to find approximate solutions of differential equations with initial conditions. The oscillation model of the ENSO is an important nonlinear differential equation which is solved analytically in this study. Compared with the exact solution from other decomposition methods, the approximate solution shows the method’s high accuracy with symbolic computation.
An Efficient Resource to Accelerate Research into the Cause and Prevention of Breast Cancer: The Love/Avon Army of Women
Authors: S Love
Published: March 2013

Background: It is well established that more research into the cause and prevention of breast cancer is needed. While studies are done in cell lines and lab animals, translation of findings to women is often delayed due to difficulty in recruitment. The Dr. Susan Love Research Foundation received a grant from the Avon Foundation for Women to form the Love/Avon Army of Women (AOW); an on-line recruitment resource designed to partner women with researchers in order to accelerate breast cancer research. Methods: Researchers submit a proposal to the AOW Scientific Advisory Committee. If a study is accepted, a mass e-mail describing the study procedures and inclusion/exclusion criteria is sent to the entire AOW database. Women sign up at www.armyofwomen.org to join and receive AOW e-mails about breast cancer research studies. Women self-select based on interest and study criteria, and undergo a secondary on-line screening before contact information is passed on to the researcher for the enrollment process. Results: Over 371,000 women have signed up, including survivors and women without a history of breast cancer, ranging from ages 18 to 100, representing all 50 US states and 49 countries. To date, the AOW has recruited for 70 studies. The diversity of the AOW members has proved beneficial for many studies, such as those needing to enroll racial/ethnic minorities, women of varying sexual orientations, or young survivors. A secondary goal of the AOW is to assist researchers new to research with human subjects. The AOW has successfully helped researchers cross the chasm, coaching them on what it takes to transition their research from animal models to human subjects. Conclusions: The AOW has proved to be a successful resource for scientists to accelerate accrual, expand the number and diversity of their subject population and to obtain exactly the type of specimens they need when they need it. This partnership between women and scientists has revolutionized research and accelerated efforts to eradicate breast cancer. The public is ready and willing to partner with the research community to find the answer to urgent clinical problems.
Smoking and Colorectal Cancer Risk by Tumor Genetic and Epigenetic Subtypes: A Molecular Pathological Epidemiology (MPE) Study
Authors: R Nishihara , AT Chan , S Ogino
Published: March 2013

Purpose: It remains to be investigated whether smoking is associated with colorectal carcinogenesis through specific epigenetic or genetic alterations, or abnormal protein expression. We comprehensively examined the influence of smoking on colorectal cancer risk by specific tumor molecular features, including epigenetic status (CpG island methylator phenotype [CIMP]), genomic instability (microsatellite instability [MSI]), oncogenic mutations (BRAF, KRAS, and PIK3CA), and tumor protein expressions (DNA methyltransferase-3B [DNMT3B], TP53, PTGS2 [cyclooxygenase-2], FASN, and CTNNB1 [b-catenin]). Methods: Follow-up of 134,204 individuals in two U.S. nationwide prospective cohorts (Nurses' Health Study [1980–2008] and Health Professionals Follow-up Study [1986–2008]) resulted in 1,292 incident rectal and colon cancers with available molecular data. Duplication method Cox proportional hazards model was used to calculate multivariate hazard ratio (HR) for developing a specific subtype of tumor according to smoking status. Results: Compared with never smokers, smoking of ≥40 cumulative pack-years was associated with increased risks for specific molecular types of colorectal cancer. Multivariate HRs are 2.12 for CIMP-high cancer (95% confidence interval [CI], 1.48- 3.03), 2.27 for MSI-high cancer (95% CI, 1.56–3.31), 2.00 for BRAF-mutated cancer (95% CI, 1.37–2.92), 1.37 for KRAS-wild-type cancer (95% CI, 1.12–1.68), 1.30 for PIK3CA-wild-type cancer (95% CI, 1.07–1.58), 1.33 for TP53-negative cancer (95% CI, 1.05–1.69), 1.37 for PTGS2-positive cancer (95% CI, 1.09–1.73), 1.36 for FASN-positive cancer (95% CI, 1.07–1.73), and 1.35 for CTNNB1-negative cancer (95% CI, 1.04–1.74). The influence of smoking significantly differed according to status of CIMP (P = 0.001 for heterogeneity test of CIMP-low vs. CIMP-high) and MSI (P = 0.0003 for heterogeneity test of MSS vs. MSI-high). There was no statistically significant differential association of smoking with other molecular subtypes. Conclusion: This molecular pathological epidemiology (MPE) study suggests that smoking might primarily cause epigenetic alterations, which lead to oncogenic mutations in colonic cells.
Cross-Sectional & Longitudinal Associations between Light-Intensity Physical Activity & Physical Function Among Cancer Survivors
Authors: C Blair , M Morey , R Desmond , R Sloane , D Snyder , H Cohen , W Demark-Wahnefried
Published: March 2013

Purpose: While moderate-vigorous intensity physical activities (MVPA) confer the greatest health benefits, evidence suggests that light-intensity activities are also beneficial, particularly for older adults and individuals with moderate-severe comorbidities. Cross-sectional and longitudinal associations between light-intensity physical activity and physical function were examined in elderly cancer survivors, who are at increased risk for age- and treatment related comorbidities, including accelerated functional decline. Methods: The analysis included 641 breast, prostate, and colorectal cancer survivors (54% female) aged 65 and older who participated in a 1-year, home-based diet and exercise intervention designed to reduce the rate of physical function decline. Pre- and post-intervention physical activity and function were assessed via the CHAMPS questionnaire, the SF-36 physical function subscale (PFS) and the Late Life Function and Disability Index basic and advanced lower-extremity function (LEF) subscales. ANCOVA was used to compare means of physical function across levels of PA intensity (low-light (LLPA): 1.0-2.0 METs; high-light (HLPA): 2.1-2.9 METs; MVPA: ≥3.0 METs). Results: After adjustment for age, sex, BMI, comorbidities, symptoms, and MVPA, increasing tertiles of baseline light-intensity activity were associated with higher scores for all 3 measures of baseline physical function (all p-values <0.005). Associations were stronger for HLPA than for LLPA. Compared with survivors who decreased or remained stable in MVPA and HLPA at the post-intervention follow-up, those who increased in HLPA, but not MVPA, reported higher physical function scores (LSMeans (95% CI): SF-36 PFS: −5.58 (−7.96, −3.20) vs. −2.54 (−5.83, 0.75), p = 0.14; basic LEF: -2.00 (−3.45, −0.55) vs. 0.28 (−1.72, 2.28), p = 0.07; advanced LEF: −2.58 (−4.00, −1.15) vs. 0.44 (-1.52, 2.40), p = 0.01). Conclusions: Our findings suggest that increasing light-intensity activities, especially HLPA, may be a viable approach to reducing the rate of physical function decline in individuals who are unable or reluctant to initiate or maintain adequate levels of moderate-intensity activities.