bluuebunny/crossref_metadata_2025 huggingface dataset:
Mapping the duskside topside ionosphere with CINDI and DMSP
Authors: Hairston Marc R. , Coley William R. , Heelis R. A.
Published: August 2010

The CINDI plasma instrument package on board the C/NOFS spacecraft performs in situ measurements of the velocity, temperature, composition, and density of ionospheric ions. In a 402 by 849 km orbit with a 13° inclination its apogee reaches the topside ionosphere at the same altitude as the polar‐orbiting DMSP spacecraft that also carry similar plasma measurement packages. Over the course of about 66 days the apogee of C/NOFS' orbit cycles once through all solar local times. This paper presents the apogee observations from the CINDI instruments between 21 August and 5 September 2008 when the C/NOFS' apogee passed through the orbital planes of the duskside equatorial crossings of the four operational DMSP spacecraft. Combining the data from all five spacecraft reveals the spatial distribution of the total ion density, the ion temperature, and the ion composition at these altitudes. Comparisons of these observed distributions from CINDI and DMSP are used to check the agreement between the new CINDI instruments and the long‐operating DMSP instruments. The results of the density and temperature measurements show good agreement, however there are two regions where the composition and temperature measurements show discrepancies that result from the limitation of the plasma instruments in an environment of extremely low density plasma composed of over 85% light ions (H+ and He+).
Observations of the magnetic field and plasma in the heliosheath by Voyager 2 from 2007.7 to 2009.4
Authors: Burlaga L. F. , Ness N. F. , Wang Y.‐M. , Sheeley N. R. , Richardson J. D.
Published: August 2010

The density and temperature profiles of the plasma measured by Voyager 2 (V2) behind the termination shock changed abruptly near 2008.6 from relatively large average values and large fluctuations during 2007.7 to 2008.6 (interval A) to relatively low average values and very small‐amplitude fluctuations during 2008.6 to 2009.4 (interval B). This paper shows that the change in the magnetic field strength B(t) was less abrupt than the plasma changes, and the fluctuations of the magnetic field strength in interval B were of moderate amplitude, with indications of a quasiperiodic structure in part of the interval. The magnetic field was directed away from the sun (positive polarity) ∼ 78% ± 5% of the time in both interval A and interval B, changing in an irregular way from positive to negative polarities throughout the interval. The polarity distribution indicates that the minimum latitudinal extent of the heliospheric current sheet (HCS) was near V2 throughout the interval, consistent with the extrapolated minimum latitudes of the HCS computed from solar magnetic field observations. Thus, V2 was observing magnetic fields from the southern polar coronal hole most of the time. The distribution of B was lognormal in interval A and Gaussian interval B.
Fracture/matrix interaction in a fracture of finite extent
Authors: Fairley Jerry P.
Published: August 2010

The behavior of a wetting front invading a fracture in an unsaturated, porous matrix is of some importance for understanding infiltration and recharge processes, contaminant transport, and similar topics. Previous investigators have examined this problem, and a number of models have been published in the literature. It is, however, difficult to observe processes inside a fracture, particularly in a field setting. Many models of fracture flow and fracture/matrix interaction therefore lack an observable quantity and instead rely on comparisons with numerical simulations to test the validity of the theoretical constructs. Here a method is proposed that avoids this difficulty by analyzing flow in a finite fracture or fracture network. The fracture is considered finite because, after some interval of injecting water to the fracture at a constant rate, the wetting front reaches the far end of the fracture and exits at a point where it can be monitored. The discharge from the fracture constitutes an observable quantity and allows comparison with field or laboratory data. A curve matching procedure is described by which parameters characterizing the fracture/matrix system may be estimated, and the method is demonstrated using output from a numerical simulation, data from a laboratory experiment, and data from two field tests.
Lunar‐dependent equatorial ionospheric electrodynamic effects during sudden stratospheric warmings
Authors: Fejer B. G. , Olson M. E. , Chau J. L. , Stolle C. , Lühr H. , Goncharenko L. P. , Yumoto K. , Nagatsuma T.
Published: August 2010

We have used plasma drift and magnetic field measurements during the 2001–2009 December solstices to study, for the first time, the longitudinal dependence of equatorial ionospheric electrodynamic perturbations during sudden stratospheric warmings. Jicamarca radar measurements during these events show large dayside downward drift (westward electric field) perturbations followed by large morning upward and afternoon downward drifts that systematically shift to later local times. Ground‐based magnetometer measurements in the American, Indian, and Pacific equatorial regions show strongly enhanced electrojet currents in the morning sector and large reversed currents (i.e., counterelectrojets) in the afternoon sector with onsets near new and full moons during northern winter warming periods. CHAMP satellite and ground‐based magnetic field observations indicate that the onset of these equatorial afternoon counterelectrojets is longitude dependent. Our results indicate that these large electrodynamic perturbations during stratospheric warming periods are due to strongly enhanced semidiurnal lunar wave effects. The results of our study can be used for forecasting the occurrence and evolution of these electrodynamic perturbations during arctic winter warmings.
Effects of irrigation on global climate during the 20th century
Authors: Puma M. J. , Cook B. I.
Published: August 2010

Various studies have documented the effects of modern‐day irrigation on regional and global climate, but none, to date, have considered the time‐varying impact of steadily increasing irrigation rates on climate during the 20th century. We investigate the impacts of observed irrigation changes over this century with two ensemble simulations using an atmosphere general circulation model. Both ensembles are forced with transient climate forcings and observed sea surface temperatures from 1902 to 2000; one ensemble includes irrigation specified by a time‐varying data set of irrigation water withdrawals. Early in the century, irrigation is primarily localized over southern and eastern Asia, leading to significant cooling in boreal summer (June–August) over these regions. This cooling spreads and intensifies by century's end, following the rapid expansion of irrigation over North America, Europe, and Asia. Irrigation also leads to boreal winter (December–February) warming over parts of North America and Asia in the latter part of the century, due to enhanced downward longwave fluxes from increased near‐surface humidity. Precipitation increases occur primarily downwind of the major irrigation areas, although precipitation in parts of India decreases due to a weaker summer monsoon. Irrigation begins to significantly reduce temperatures and temperature trends during boreal summer over the Northern Hemisphere midlatitudes and tropics beginning around 1950; significant increases in precipitation occur in these same latitude bands. These trends reveal the varying importance of irrigation‐climate interactions and suggest that future climate studies should account for irrigation, especially in regions with unsustainable irrigation resources.
Operation Analysis of a Compound Energy System – Exhaust Heat Use Plan when Connecting Solar Modules to a Fuel Cell Network
Authors: Obara Shin’ya
Published: August 2010

The energy supply method by distributed power supply is expected from the transportation loss of the power and a decrease in heat. The system using especially renewable energy and a fuel cell is excellent from the viewpoint of the environment. However, the efficiency of the whole system depends on the amount of utilization of exhaust heat. The system assumed in this Chapter installs a small fuel cell and a solar module in 12 buildings, connects each building with hot-water piping, and supplies fuel cell exhaust heat. The hot-water piping path that results in minimum heat release loss was investigated in the optimization analysis using a genetic algorithm. As a result, the optimal path of the hot-water piping considering the production of electricity of a solar module and ambient temperature was clarified.
Power-Independent House Using PEFC – Operation Plan of a Combined Fuel Cell Cogeneration, Solar Module, and Geothermal Heat Pump System
Authors: Obara Shin’ya
Published: August 2010

A chromosome model that simulates the operation patterns of an energy system was introduced into a simple Genetic Algorithm, and a method of dynamic optimization was developed. This Chapter analyzes the operation planning of an energy system that uses in combination a solar power module, proton exchange membrane fuel cell co-generation (PEFC-CGS) with methanol steam reforming, a geo-thermal heat pump, heat storage and battery, commercial power, and a kerosene boiler. The hours of operation of each energy device and the rate of the energy output were calculated by having introduced the analysis program developed by this study. Three objective functions, (a) Minimization of operation cost, (b) Minimization of the error of demand-and-supply balance, (c) Minimization of the amount of green-house gas discharge were given to the optimization analysis of the system. Furthermore, the characteristics of the system operation planning under each objective function are described.
PEFC/Green Energy Compound System (2) – Overall Efficiency of a PEFC with a Bioethanol Solar Reforming System for Individual Houses
Authors: Obara Shin’ya
Published: August 2010

The development of a bioethanol reforming system for fuel cells (FBSR: fuel cell with bioethanol steam reforming) using sunlight as a heat source was investigated. If ethanol purity is high, the production method of the bioethanol used for the proposal system will not be limited. The overall efficiency of the production of electricity and heat power of this system was determined by examining its thermal output characteristic. The FBSR was introduced into standard individual houses in Sapporo, Japan for analysis. However, the amount of solar radiation fluctuation of the representative day in August (summer season) in this analysis is large compared with the representative day in March (winter season). It depends for the overall efficiency of the system on the amount of solar radiation fluctuation rather than the amount of solar radiation.
PEFC/Green Energy Compound System (3) – Fuel Cell Microgrid with Wind-Power Generation
Authors: Obara Shin'ya
Published: August 2010

An independent micro-grid that connects with wind power has the potential to reduce energy costs, and reduce the amount of greenhouse gas discharge. However, the frequency and voltage of a micro-grid may not be stable over a long time due to the input of unstable renewable energy, and changes in short-period power load that are difficult to predict. Thus, when planning the installation of a micro-grid, it is necessary to investigate the dynamic characteristics of the power. About the micro-grid composed from ten houses, a 2.5kW PEFC is installed in one building, and this fuel cell operated corresponding to a base load is assumed. The dynamic characteristics of this micro-grid were investigated in numerical analysis, and the cost of fuel consumption and efficiency was also calculated. Moreover, the stabilization time of the micro-grid and its dynamic characteristics accompanied by wind-power-generation and fluctuation of the power load were clarified.
Solar Cell/Diesel Engine Compound System with Production-of-Electricity Prediction
Authors: Obara Shin’ya
Published: August 2010

A microgrid with the sustainable energy is expected to be a distributed energy system that exhibits quite a small environmental impact. In the past study, the production-of-electricity prediction algorithm (PAS) of the solar cell was developed. In PAS, a layered neural network is made to learn based on past weather data and the operation plan of the compound system of a solar cell and other energy systems was examined using this prediction algorithm. In this Chapter, a dynamic operational scheduling algorithm is developed using a neural network and a genetic algorithm (GA) to provide predictions for solar cell power output. We also do a case study analysis in which we use this algorithm to plan the operation of a system that connects nine houses in Sapporo in Japan to a microgrid composed of power equipment and a polycrystalline silicon solar cell. In this work, the relationship between the accuracy of output prediction of the solar cell and the operation plan of the microgrid was clarified.
Dynamic Characteristics of Power for PEFC Compound System
Authors: Obara Shin’ya
Published: August 2010

The method of determination of the control variables for a system controller, which controls the power output of a PEFC system during power load fluctuations, was considered. The operation was clarified for the response characteristics of power generation for setting the control variables of proportional action and integral action considered to be the optimal for the system controller. The power load pattern of an individual house consists of loads usually moved up and down rapidly for a short time. This Chapter investigates the relation of the control variables and power generation efficiency when adding change that simulates the load of a house to PEFC cogeneration. As a result, it was shown that an operation, minimally influenced by load fluctuations, can be performed by changing the control variables using the value of the power load of a system.
Clean by Light Irradiation
Authors: Augugliaro Vincenzo , Loddo Vittorio , Pagliaro Mario , Palmisano Giovanni , Palmisano Leonardo
Published: August 2010

The book deals with the environmentally friendly cleaning materials functionalized with TiO2, a widely known semiconductor giving rise to redox reactions under artificial or solar irradiation. The role of Titanium dioxide in the worldwide community is introduced first. The fundamental working principles of heterogeneous photocatalysis follow and a critical section on the semiconductor bulk and surface properties open the way to the differences between TiO2 blend features with respect to analogous thin film layouts. Then follows the main section of the book which deals with the techniques applied to manufactured commercial devices, ranging from glasses to textiles and from concrete and other construction materials to paintings. Also road asphalt and other devices, such as photocatalytic air conditioning machines are outlined. Last generation materials, not yet commercialized, and the deposition techniques applied to prepare them are also widely discussed. The final part of the book covers the difficult and modern topic of standardization and comparison of performance of photocatalytic processes and in particular the guidelines proposed by various worldwide organizations for standardization are discussed. The book covers the general matters as well as the practical applications with the supporting methods discussed in detail. This book brings together a team of highly experienced and well-published experts in the field, providing a comprehensive view of the applications of supported titanium dioxide.
Lysophosphatidylcholines activate G2A inducing Gαi-1-/Gαq/11- Ca2+ flux, Gβγ-Hck activation and clathrin/β-arrestin-1/GRK6 recruitment in PMNs
Authors: Khan Samina Y. , McLaughlin Nathan J. D. , Kelher Marguerite R. , Eckels Phillip , Gamboni-Robertson Fabia , Banerjee Anirban , Silliman Christopher C.
Published: August 2010

Lyso-PCs (lysophosphatidylcholines) are a mixture of lipids that accumulate during storage of cellular blood components, have been implicated in TRALI (transfusion-related acute lung injury) and directly affect the physiology of neutrophils [PMNs (polymorphonuclear leucocytes)]. Because the G2A receptor, expressed on PMNs, has been reported to recognize lyso-PCs, we hypothesize that lyso-PC activation of G2A causes the increases in cytosolic Ca2+ via release of Gα and Gβγ subunits, kinase activation, and the recruitment of clathrin, β-arrestin-1 and GRK6 (G-protein receptor kinase 6) to G2A for signal transduction. PMNs were isolated by standard techniques, primed with lyso-PCs for 5–180 s, and lysed for Western blot analysis, immunoprecipitation or subcellular fractionation, or fixed and smeared on to slides for digital microscopy. The results demonstrated that lyso-PCs cause rapid activation of the G2A receptor through S-phosphorylation and internalization resulting in Gαi-1 and Gαq/11 release leading to increases in cytosolic Ca2+, which was inhibited by an antibody to G2A or intracellular neutralization of these subunits. Lyso-PCs also caused the release of the Gβγ subunit which demonstrated a physical interaction (FRET+) with activated Hck (haemopoietic cell kinase; Tyr411). Moreover, G2A recruited clathrin, β-arrestin-1 and GRK6: clathrin is important for signal transduction, GRK6 for receptor de-sensitization, and β-arrestin-1 both propagates and terminates signals. We conclude that lyso-PC activation of G2A caused release of Gαi-1, Gαq/11 and Gβγ, resulting in cytosolic Ca2+ flux, Hck activation, and recruitment of clathrin, β-arrestin-1 and GRK6.
Functional diversity of the hnRNPs: past, present and perspectives
Authors: Han Siew Ping , Tang Yue Hang , Smith Ross
Published: August 2010

The hnRNPs (heterogeneous nuclear ribonucleoproteins) are RNA-binding proteins with important roles in multiple aspects of nucleic acid metabolism, including the packaging of nascent transcripts, alternative splicing and translational regulation. Although they share some general characteristics, they vary greatly in terms of their domain composition and functional properties. Although the traditional grouping of the hnRNPs as a collection of proteins provided a practical framework, which has guided much of the research on them, this approach is becoming increasingly incompatible with current knowledge about their structural and functional divergence. Hence, we review the current literature to examine hnRNP diversity, and discuss how this impacts upon approaches to the classification of RNA-binding proteins in general.
Light on fluorescent lipids in rafts: a lesson from model membranes
Authors: Kahya Nicoletta
Published: August 2010

Tracking fluorescent lipids in cellular membranes has been applied for decades to shed light on membrane trafficking, sorting, endocytosis and exocytosis, viral entry, and to understand the functional relevance of membrane heterogeneity, phase separation and lipid rafts. However, fluorescent probes may display different organizing behaviour from their corresponding endogenous lipids. A full characterization of these probes is therefore required for proper interpretation of fluorescence microscopy data in complex membrane systems. Model membrane studies provide essential clues that guide us to design and interpret our experiments, help us to avoid pitfalls and resolve artefacts in complex cellular environments. In the present issue of the Biochemical Journal, Juhasz, Davis and Sharom demonstrate the importance of testing lipid probes systematically in heterogeneous model membranes of specific composition and well-defined thermodynamic properties. The phase-partitioning behaviour of fluorescent probes, alone and/or in combination, cannot simply be assumed, but has to be fully characterized.
Sitagliptin prevents the development of metabolic and hormonal disturbances, increased β-cell apoptosis and liver steatosis induced by a fructose-rich diet in normal rats
Authors: Maiztegui Bárbara , Borelli María I. , Madrid Viviana G. , Del Zotto Héctor , Raschia María A. , Francini Flavio , Massa María L. , Flores Luis E. , Rebolledo Oscar R. , Gagliardino Juan J.
Published: August 2010

The aim of the present study was to test the effect of sitagliptin and exendin-4 upon metabolic alterations, β-cell mass decrease and hepatic steatosis induced by F (fructose) in rats. Normal adult male Wistar rats received a standard commercial diet without (C) or with 10% (w/v) F in the drinking water (F) for 3 weeks; animals from each group were randomly divided into three subgroups: untreated (C and F) and simultaneously receiving either sitagliptin (CS and FS; 115.2 mg/day per rat) or exendin-4 (CE and FE; 0.35 nmol/kg of body weight, intraperitoneally). Water and food intake, oral glucose tolerance, plasma glucose, triacylglycerol (triglyceride), insulin and fructosamine concentration, HOMA-IR [HOMA (homoeostasis model assessment) for insulin resistance], HOMA-β (HOMA for β-cell function) and liver triacylglycerol content were measured. Pancreas immunomorphometric analyses were also performed. IGT (impaired glucose tolerance), plasma triacylglycerol, fructosamine and insulin levels, HOMA-IR and HOMA-β indexes, and liver triacylglycerol content were significantly higher in F rats. Islet β-cell mass was significantly lower in these rats, due to an increase in the percentage of apoptosis. The administration of exendin-4 and sitagliptin to F animals prevented the development of all the metabolic disturbances and the changes in β-cell mass and fatty liver. Thus these compounds, useful in treating Type 2 diabetes, would also prevent/delay the progression of early metabolic and tissue markers of this disease.
Semantic Abilities in Children With Pragmatic Language Impairment: The Case of Picture Naming Skills
Authors: Ketelaars Mieke Pauline , Hermans Suzanne Irene Alphonsus , Cuperus Juliane , Jansonius Kino , Verhoeven Ludo
Published: August 2010

Purpose

The semantic abilities of children with pragmatic language impairment (PLI) are subject to debate. The authors investigated picture naming and definition skills in 5-year-olds with PLI in comparison to typically developing children.

Method

84 children with PLI and 80 age-matched typically developing children completed receptive vocabulary, picture naming, and definition tasks.

Results

The PLI group scored lower on the receptive vocabulary and picture naming tasks. Word length and frequency affected naming accuracy in both groups. Children with PLI showed higher numbers of semantic errors, nonrelated errors, and omissions and circumlocutions. The error-type distribution differed between groups: PLI children showed disproportionate levels of nonrelated errors. In the definition task, PLI children showed lower information accuracy for accurately named pictures and comparable accuracy for incorrectly named pictures. Qualitative analysis suggested a high incidence of pragmatically inappropriate definitions for the PLI group. Naming accuracy for both groups improved equally after giving semantic cues.

Conclusions

These findings suggest a deficit in object identification and/or naming selection. It might be premature to conclude that children with PLI show normal semantic abilities. The results are largely consistent with a general language delay; however, there is also some evidence of a qualitative difference between both groups.
Strong strain-dependent elastic stiffness in ultrathin Pt films on MgO
Authors: Nakamura N. , Kake Y. , Ogi H. , Hirao M.
Published: August 2010

In this study, strong strain dependence of the elastic stiffness is found in polycrystalline Pt films. Epitaxial and polycrystalline Pt films thinner than 100 nm were deposited on monocrystal MgO substrates and resonance frequency of longitudinal standing wave in the film thickness direction was measured by picosecond ultrasound. In epitaxial Pt film, the resonance frequency was comparable to or smaller than the value expected from the elastic stiffness of bulk Pt, indicating softening of epitaxial Pt films, where nanoscale defects were observed: the softening was attributed to the defects. However, in polycrystalline Pt films, resonance frequency increased as the film thickness decreased and when the film thickness was smaller than 20 nm, the value exceeded the predicted value from the bulk stiffness, indicating the stiffening of the Pt film. Furthermore, resonance frequency showed good correlation with the strain. This trend is expected considering the higher elasticity. However, the slope between the resonance frequency and the strain is ten times as large as the value deduced from third-order elastic constant.
Origins of magnetism in transition metal doped CuI
Authors: Wang Jing , Li Jingbo , Li Shu-Shen
Published: August 2010

Cupric iodide is a p-type semiconductor and has a large band gap. Doping of Mn, Co, and Ni are found to make γ-CuI ferromagnetic ground state, while Cr-doped and Fe-doped CuI systems are stabilized in antiferromagnetic configurations. The origins of the magnetic ordering are demonstrated successfully by the phenomenological band coupling model based on d-d level repulsions between the dopant ions. Furthermore, using a molecular-orbital bonding model, the electronic structures of the doped CuI are well understood. According to Heisenberg model, high-TC may be expected for CuI:Mn and CuI:Ni if there are no native defects or other impurities.
Optical beating Brillouin scattering spectroscopic measurements of high-temperature gas
Authors: Minami Yasuo , Yogi Takeshi , Sakai Keiji
Published: August 2010

The sound velocity of air at high temperature was measured in the 10 MHz frequency region using optical beating Brillouin scattering spectroscopy. The sound velocity dependence on temperature was observed, and the molecular weight of the gas was obtained and is in agreement with the literature value. The present experiment will enable the observation of gas phase rotation-translation (R-T) relaxation, for example, the R-T relaxation of nitrogen at high temperature that occurs in the 100 MHz region. The high-temperature sound velocity could also be used to measure the molecular fraction of the gas in this experiment.
Exceptional electromagnetic interference shielding properties of ferromagnetic microwires enabled polymer composites
Authors: Qin F. X. , Peng H. X. , Pankratov N. , Phan M. H. , Panina L. V. , Ipatov M. , Zhukova V. , Zhukov A. , Gonzalez J.
Published: August 2010

We present systematic studies of the electromagnetic interference (EMI) shielding and microwave properties of a new class of shielding material, i.e., the ferromagnetic microwires-embedded polymer composites. We show that at 1–2 GHz the shielding effectiveness (SE) of the continuous-wire composite reaches a high value of 18 dB (98.4% attenuation) for a very low filler loading of 0.024% and a thickness of 0.64 mm. The normalized SE of this new composite is about 70 times higher than that of the bucky paper-based composite and is two to four orders of magnitude higher than those of other shielding candidate materials. Complex permeability, permittivity, and impedance experiments reveal that the absorption of electromagnetic radiation is a dominant mechanism for EMI shielding of the studied composites. The advantages of high shielding efficiency, good physical integrity, low fabrication costs, and multifunctionalities make them an attractive candidate material for a variety of technological applications.
High-frequency viscosity of concentrated porous particles suspensions
Authors: Abade Gustavo C. , Cichocki Bogdan , Ekiel-Jeżewska Maria L. , Nägele Gerhard , Wajnryb Eligiusz
Published: August 2010

We determine the high-frequency limiting shear viscosity, η∞, in colloidal suspensions of rigid, uniformly porous spheres of radius a as a function of volume fraction ϕ and (inverse) porosity parameter x. Our study covers the complete fluid-state regime. The flow inside the spheres is modeled by the Debye–Bueche–Brinkman equation using the boundary condition that fluid velocity and stress change continuously across the sphere surfaces. The many-sphere hydrodynamic interactions in concentrated systems are fully accounted for by a precise hydrodynamic multipole method encoded in our HYDROMULTIPOLE program extended to porous particles. A truncated virial expansion is used to derive an accurate and easy-to-use generalized Saitô formula for η∞. The simulation data are used to test the performance of two simplifying effective particle models. The first model describes the effective particle as a nonporous sphere characterized by a single effective radius aeff(x)<a. In the more refined second model, the porous spheres are modeled as spherical annulus particles with an inner hydrodynamic radius aeff(x) defining the nonporous dry core and characterizing hydrodynamic interactions, and an outer excluded volume radius a characterizing the unchanged direct interactions. Only the second model is in a satisfactory agreement with the simulation data.
Energy transfer in binary collisions of two gyrating charged particles in a magnetic field
Authors: Nersisyan H. B. , Zwicknagel G.
Published: August 2010

Binary collisions of the gyrating charged particles in an external magnetic field are considered within a classical second-order perturbation theory, i.e., up to contributions that are quadratic in the binary interaction, starting from the unperturbed helical motion of the particles. The calculations are done with the help of a binary collision treatment, which is valid for any strength of the magnetic field and involves all harmonics of the particles’ cyclotron motion. The energy transfer is explicitly calculated for a regularized and screened potential, which is both of finite range and nonsingular at the origin. The validity of the perturbation treatment is evaluated by comparing with classical trajectory Monte Carlo (CTMC) calculations which also allow one to investigate the strong collisions with large energy and velocity transfer at low velocities. For large initial velocities, on the other hand, only small velocity transfers occur. There the nonperturbative numerical CTMC results agree excellently with the predictions of the perturbative treatment.
Surface spin-glass and exchange bias in Sr2FeMoO6 nanoparticle
Authors: Middey Srimanta , Jana Somnath , Ray Sugata
Published: August 2010

Tunneling magnetoresistance in polycrystalline double perovskite Sr2FeMoO6 exhibits many unusual features, which can be efficiently probed by manipulating the tunnel barriers/grain surfaces. Accordingly, many experimental reports appeared on nanosized particles of Sr2FeMoO6 with largely enhanced grain boundary contributions. However, for the first time we report the existence of a spin-glasslike component, along with conventional ferromagnetism, in well-characterized Sr2FeMoO6 nanoparticles, which has been critically confirmed by the perceptible exchange bias effect, observed in these nanoparticles. Our results suggest that the spin-glass component is likely to reside on the surface of each particle, which probably provides useful clues about the unusual tunneling magnetoresistance responses, always exhibited by nanocrystalline Sr2FeMoO6.
Crossover from reversible to irreversible magnetic exchange-spring processes in antiferromagnetically exchange-coupled soft/hard bilayer structures
Authors: Guo Guang-hua , Zhang Guang-fu , Wang Xi-guang
Published: August 2010

The demagnetization processes of antiferromagnetically exchange-coupled soft/hard bilayer structures have been studied using a one-dimensional atomic chain model, taking into account the anisotropies of both soft and hard layers. It is found that for bilayer structures with strong interfacial exchange coupling, the demagnetization process exhibits typical reversible magnetic exchange-spring behavior. However, as the strength of the interfacial exchange coupling is decreased, there is a crossover point Ashc, after which the process becomes irreversible. The phase diagram of reversible and irreversible exchange-spring processes is mapped in Ash and Ns plane, where Ash and Ns are the interfacial exchange coupling and soft layer thickness, respectively. The thickness dependence of the bending field, which characterizes the onset of the exchange spring in the soft layer, is numerically examined and compared with analytical models.
Nanocrystals formation and intense green emission in thermally annealed AlN:Ho films for microlaser cavities and photonic applications
Authors: Maqbool Muhammad , Ali Ghafar , Cho Sung Oh , Ahmad Iftikhar , Mehmood Mazhar , Kordesch Martin E.
Published: August 2010

Plasma magnetron sputtered thin films of AlN:Ho deposited on flat silicon substrates and optical fiber were characterized and analyzed for structural changes after thermal annealing at 1173 K for 40 min, by atomic force microscopy (AFM). The films grown, at liquid nitrogen temperature, on silicon substrates were amorphous while those deposited around optical fiber were crystalline. The films were also investigated for any change in the luminescence when thermal activation was performed for 40 min in a nitrogen atmosphere. The AFM analysis identified the existence of crystalline structures in parts of the films after thermal annealing. The x-ray diffraction could not provide those results. The films around optical fiber were crystalline even deposited at liquid nitrogen temperature. Clearly, amorphous films are hard to achieve on smaller substrate size. Direct observation of green emission is possible with naked eye, when the thermally annealed films are studied under cathodoluminescence. The green emission occurs at 549 nm as a result from S52→I58 transition in Ho3+ that enhanced with thermal activation, making it a very useful candidate for photonic and optical devices applications.
Laser-driven quasimonoenergetic proton burst from water spray target
Authors: Ramakrishna B. , Murakami M. , Borghesi M. , Ehrentraut L. , Nickles P. V. , Schnürer M. , Steinke S. , Psikal J. , Tikhonchuk V. , Ter-Avetisyan S.
Published: August 2010

A narrow band proton bursts at energies of 1.6±0.08 MeV were observed when a water spray consisting of ∅(150 nm)-diameter droplets was irradiated by an ultrashort laser pulse of about 45 fs duration and at an intensity of 5×1019 W/cm2. The results are explained by a Coulomb explosion of sub-laser-wavelength droplets composed of two ion species. The laser prepulse plays an important role. By pre-evaporation of the droplets, its diameter is reduced so that the main pulse can interact with a smaller droplet, and this remaining bulk can be ionized to high states. In the case of water, the mixture of quite differently charged ions establishes an “iso-Coulomb-potential” during the droplet explosion such that protons are accelerated to a peak energy with a narrow energy spread. The model explains this crucial point, which differs critically from usual Coulomb explosion or ion sheath acceleration mechanisms.
Immunohistochemical study of the ubiquitin - nuclear factor-ΚB pathway in the endometrium of the baboon (Papio anubis) with and without endometriosis
Authors: Ilad Romina S. , Fleming Steven D. , Murphy Christopher R. , Fazleabas Asgerally T.
Published: August 2010

The aim of the present study was to conduct a semiquantitative immunohistochemical investigation into the levels of intermediary proteins within the nuclear factor (NF)-κB pathway throughout the menstrual cycle in a non-human primate, namely the baboon (Papio anubis), with and without endometriosis. Formalin-fixed eutopic (n = 2–4) and ectopic (n = 6–7) endometrial tissues from baboons at the mid-luteal phase were embedded in paraffin and examined for NF-κB pathway components (i.e. IκB kinase (IKK) α, IKKβ, phosphorylated (phospho-) IκBα and phospho-NF-κB p65 subunit), ubiquitin, 19S proteasome and the NF-κB activator tumour necrosis factor (TNF)-α. Similarly, endometrial tissues from baboons at the late follicular, mid-luteal and menses phase (n = 2–4) were investigated to determine the levels of these proteins throughout the menstrual cycle. Cytoplasmic stromal IKKα and glandular 19S proteasome immunostaining was elevated in the ectopic endometrium, whereas levels of ubiquitin, phospho-p65, IKKβ, TNF-α and nuclear 19S proteasome were similar in the eutopic and ectopic endometrium. A significant decrease in phospho-IκBα nuclear immunostaining was observed within glandular cells of the ectopic endometrium. In the eutopic endometrium, IKKα, ubiquitin and 19S proteasome immunostaining was elevated in different phases of the menstrual cycle, whereas levels of phospho-p65, IKKβ, phospho-IκBα and TNF-α remained unchanged. We have demonstrated that, in the baboon endometriosis model, levels of IKKα immunostaining are elevated, whereas those of phospho-IκBα are reduced, consistent with the hypothesis that excessive NF-κB activity plays a role in reducing ectopic endometrial apoptosis, which contributes to the pathophysiology of endometriosis. Further studies are required to confirm a causal association between elevated IKKα levels and reduced endometrial apoptosis.
Positive effect of FSH but not LH on early development of the dominant follicle in mares
Authors: Checura C. M. , Beg M. A. , Parrish J. J. , Ginther O. J.
Published: August 2010

The effects of FSH, LH or both on follicular growth and intrafollicular free insulin-like growth factor (IGF)-1 and oestradiol were investigated in mares after the beginning of deviation (largest follicle ≥ 20 mm; Hour 0). A single treatment with a gonadotropin-releasing hormone antagonist (acyline) was given at Hour 3 to suppress the concentrations of FSH and LH. Five groups (n = 5 mares per group) were evaluated in the present study: (1) control; (2) acyline treated; (3) acyline + recombinant equine (re) FSH treated; (4) acyline + reLH treated; and (5) combined acyline + reFSH + reLH treated. Beginning at Hour 3, reFSH and reLH were given at 6-h intervals in eight decreasing or increasing doses, respectively. The reFSH and reLH prevented the acyline-induced decreases in FSH and LH, respectively. Diameters and concentrations of intrafollicular free IGF-1 and oestradiol of the two largest follicles at Hour 48 did not differ significantly between the control and acyline + FSH groups, but were reduced (P < 0.05) similarly in the acyline and acyline + LH groups. The combination of reFSH and reLH was no more effective than reFSH alone. The results demonstrate a role for FSH but not LH in the growth of the largest follicle and intrafollicular concentrations of free IGF-1 and oestradiol during the 48 h after the beginning of deviation in mares.
Ultrasonographically documented early pregnancy loss in an Asian elephant (Elephas maximus)
Authors: Lueders Imke , Drews Barbara , Niemuller Cheryl , Gray Charlie , Rich Peter , Fickel Jörns , Wibbelt Gudrun , Göritz Frank , Hildebrandt Thomas B.
Published: August 2010

Early embryonic resorption or fetal loss is known to occur occasionally in captive elephants; however, this has mostly been reported anecdotally. The present study documents the case of a 24-year-old, multiparous Asian elephant cow that suffered embryonic death and resorption at around 18 weeks of gestation. From ovulation onwards, this female was sonographically examined 58 times. Blood was collected twice weekly for progestagen determination via enzyme immunoassay. On Day 42 after ovulation, a small quantity of fluid was detected in the uterine horn, which typically indicates the presence of a developing conceptus. Repeated inspections followed what appeared to be a normal pregnancy until Day 116. However, on Day 124, signs of embryonic life were absent. Progestagen concentrations started declining two weeks later, reaching baseline levels one month after embryonic death. Retrospectively, ultrasound examination revealed several abnormalities in the uterine horn. Besides an existing leiomyoma, multiple small cystic structures had formed in the endometrium at the implantation site and later in the placenta. These pathological findings were considered as possible contributors to the early pregnancy failure. PCR for endotheliotropic elephant herpes virus (EEHV) (which had occurred previously in the herd) as well as serology for other infectious organisms known to cause abortion in domestic animals did not yield any positive results. Although no definitive reason was found for this pregnancy to abort, this ultrasonographically and endocrinologically documented study of an early pregnancy loss provides important insights into the resorption process in Asian elephants.
Survival and apoptosis rates after vitrification in cryotop devices of in vitro-produced calf and cow blastocysts at different developmental stages
Authors: Morató Roser , Izquierdo Dolors , Paramio Maria Teresa , Mogas Teresa
Published: August 2010

Two experiments were designed to determine the ability of in vitro-cultured blastocysts at different stages of development to survive the vitrification procedure using cryotop devices. Day 7 and Day 8 embryos were classified as non-expanded, expanded or hatching and/or hatched blastocysts. In the first experiment, we examined the survival rate of vitrified–warmed blastocysts after 3 h incubation in synthetic oviducal fluid (SOF) medium. In the second experiment, vitrified–warmed blastocysts were evaluated using the terminal deoxyribonucleotidyl transferase-mediated dUTP–digoxigenin nick end-labelling (TUNEL) technique to detect nuclei with damaged DNA. In both experiments, results for cow and calf blastocysts were compared. No differences in survival rates were observed after vitrification of Day 8 expanded (52.4%) and hatched (50%) cow blastocysts or Day 8 expanded (54.5%) and hatched (59.4%) calf blastocysts. When embryos were vitrified on Day 7, survival rates of 78.4% and 66.7% were observed after warming expanded and hatched cow blastocysts, respectively, compared with rates of 80% and 76.9%, respectively, for calf blastocysts. Lowest survival rates were recorded for non-expanded blastocysts (26%–54%) compared with the other developmental stages, particularly those vitrified at Day 8 (≤40%). The DNA integrity index obtained after vitrification–warming was comparable to that for control fresh blastocysts, regardless of the length of embryo culture, the developmental stage of the embryo or the source of the oocytes. Our findings suggest that the cryotop vitrification method is particularly useful for the cryopreservation of blastocysts presenting with a high degree of expansion (expanded or hatched blastocysts), particularly when vitrification is performed after 7 days of in vitro embryo culture.
Label-free imaging, detection, and mass measurement of single viruses by surface plasmon resonance
Authors: Wang Shaopeng , Shan Xiaonan , Patel Urmez , Huang Xinping , Lu Jin , Li Jinghong , Tao Nongjian
Published: August 2010

We report on label-free imaging, detection, and mass/size measurement of single viral particles in solution by high-resolution surface plasmon resonance microscopy. Diffraction of propagating plasmon waves along a metal surface by the viral particles creates images of the individual particles, which allow us to detect the binding of the viral particles to surfaces functionalized with and without antibodies. We show that the intensity of the particle image is related to the mass of the particle, from which we determine the mass and mass distribution of influenza viral particles with a mass detection limit of approximately 1 ag (or 0.2 fg/mm
2
). This work demonstrates a multiplexed method to measure the masses of individual viral particles and to study the binding activity of the viral particles.
METAREP: JCVI metagenomics reports—an open source tool for high-performance comparative metagenomics
Authors: Goll Johannes , Rusch Douglas B. , Tanenbaum David M. , Thiagarajan Mathangi , Li Kelvin , Methé Barbara A. , Yooseph Shibu
Published: August 2010

Summary: JCVI Metagenomics Reports (METAREP) is a Web 2.0 application designed to help scientists analyze and compare annotated metagenomics datasets. It utilizes Solr/Lucene, a high-performance scalable search engine, to quickly query large data collections. Furthermore, users can use its SQL-like query syntax to filter and refine datasets. METAREP provides graphical summaries for top taxonomic and functional classifications as well as a GO, NCBI Taxonomy and KEGG Pathway Browser. Users can compare absolute and relative counts of multiple datasets at various functional and taxonomic levels. Advanced comparative features comprise statistical tests as well as multidimensional scaling, heatmap and hierarchical clustering plots. Summaries can be exported as tab-delimited files, publication quality plots in PDF format. A data management layer allows collaborative data analysis and result sharing.

Availability: Web site http://www.jcvi.org/metarep; source code http://github.com/jcvi/METAREP

Contact:  syooseph@jcvi.org

Supplementary information:  Supplementary data are available at Bioinformatics online.
RDP3: a flexible and fast computer program for analyzing recombination
Authors: Martin Darren P. , Lemey Philippe , Lott Martin , Moulton Vincent , Posada David , Lefeuvre Pierre
Published: August 2010

Summary: RDP3 is a new version of the RDP program for characterizing recombination events in DNA-sequence alignments. Among other novelties, this version includes four new recombination analysis methods (3SEQ, VISRD, PHYLRO and LDHAT), new tests for recombination hot-spots, a range of matrix methods for visualizing over-all patterns of recombination within datasets and recombination-aware ancestral sequence reconstruction. Complementary to a high degree of analysis flow automation, RDP3 also has a highly interactive and detailed graphical user interface that enables more focused hands-on cross-checking of results with a wide variety of newly implemented phylogenetic tree construction and matrix-based recombination signal visualization methods. The new RDP3 can accommodate large datasets and is capable of analyzing alignments ranging in size from 1000×10 kilobase sequences to 20×2 megabase sequences within 48 h on a desktop PC.

Availability: RDP3 is available for free from its web site http://darwin.uvigo.es/rdp/rdp.html

Contact:  darrenpatrickmartin@gmail.com

Supplementary information: The RDP3 program manual contains detailed descriptions of the various methods it implements and a step-by-step guide describing how best to use these.