bluuebunny/crossref_metadata_2025 huggingface dataset:
Core–Shell Structured Polystyrene/BaTiO3 Hybrid Nanodielectrics Prepared by In Situ RAFT Polymerization: A Route to High Dielectric Constant and Low Loss Materials with Weak Frequency Dependence
Authors: Yang Ke , Huang Xingyi , Xie Liyuan , Wu Chao , Jiang Pingkai , Tanaka Toshikatsu
Published: August 2012

A novel route to prepare core–shell structured nanocomposites with excellent dielectric performance is reported. This approach involves the grafting of polystyrene (PS) from the surface of BaTiO3 by an in situ RAFT polymerization. The core–shell structured PS/BaTiO3 nanocomposites not only show significantly increased dielectric constant and very low dielectric loss, but also have a weak frequency dependence of dielectric properties over a wide range of frequencies. In addition, the dielectric constant of the nanocomposites can also be easily tuned by varying the thickness of the PS shell. Our method is very promising for preparing high‐performance nanocomposites used in energy‐storage devices.
Cognitive testing in the diagnosis of parkinsonian disorders: A critical appraisal of the literature
Authors: Lee Will , Williams David R. , Storey Elsdon
Published: August 2012

A number of cognitive abnormalities have been identified as putative diagnostic markers in neurodegenerative parkinsonism based on statistically significant differences between diseases. The effect sizes of these differences frequently have not been reported, making practical interpretation of the results difficult. The objective of this study was to assess the potential contribution of cognitive testing to the diagnosis of parkinsonian disorders by quantifying effect size of previously identified significant differentiating cognitive features. A Medline search identified 1038 articles. Nineteen studies directly comparing at least 2 of Parkinson's disease, progressive supranuclear palsy, multiple system atrophy, and corticobasal syndrome/degeneration were selected. Cohen'sdand positive likelihood ratio were calculated as appropriate for cognitive tests showing statistically significant differences between diseases. Clinically useful differences were considered present when Cohen'sd> 1 or the positive likelihood ratio > 2 and were considered high when Cohen'sd> 1.94 or the positive likelihood ratio > 10. Only 16 of 141 cognitive tests were found to be highly useful. Cognitive testing was only moderately helpful in separating Parkinson's disease and multiple system atrophy. Inferior performance on phonemic (d= 1.56–2.13) and semantic (d= 1.43–2.13) verbal fluency, the Trail‐Making Test (d= 1.63–1.95) and the Wisconsin Card Sorting Test (d= 1.63–2.22) were moderately to very useful in separating progressive supranuclear palsy from Parkinson's disease and multiple system atrophy. Cognitive testing could not differentiate corticobasal syndrome from other parkinsonian disorders, although sequential orobuccal apraxia was very useful (d= 2.01–2.23). Few of the cognitive tests separating parkinsonian disorders identified from previous studies have sufficient effect size to be practically useful. Even these features must be interpreted in conjunction with other clinical characteristics to be helpful diagnostically. © 2012MovementDisorder Society
Effect of metal contamination on recombination properties of extended defects in multicrystalline Si
Authors: Feklisova O. V. , Yu X. , Yang D. , Yakimov E. B.
Published: August 2012

The effect of iron and copper contamination on the recombination properties of extended defects in multicrystalline Si is investigated by the Electron Beam Induced Current (EBIC) method. Plastically deformed Si samples containing dislocations and dislocation trails are also studied for a comparison. It is shown that Fe contamination leads to an essential increase of the EBIC contrast of electrically active grain boundaries and dislocation trails. The EBIC contrast of deformation induced dislocations also increases after iron diffusion while the recombination activity of grown‐in dislocations in multicrystalline Si does not practically change after such treatment. Cu contamination also leads to an essential increase of the EBIC contrast of electrically active grain boundaries and dislocation trails. But dislocation contrast in both plastically deformed Si and multicrystalline Si does not practically increase after Cu contamination. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Recombination process in solar cells: Impact on the carrier transport
Authors: Gurevich Yuri G. , Velázquez‐Pérez Jesus E.
Published: August 2012

Thickness of Si solar cells is being reduced below 200 µm to reduce costs and improve their performance. In conventional solar cells recombination of photo‐generated charge carriers plays a major limiting role in the cell efficiency. High quality thin‐film solar cells may overcome this limit if the minority diffusion lengths become large as compared to the cell dimensions, but, strikingly, the conventional model fails to describe the cell electric behaviour under these conditions. Moreover, it is shown that in the conventional model the reverse‐saturation current diverges (tends to infinity) in thin solar cells. A new formulation of the basic equations describing charge carrier transport in the cell along with a set of boundary conditions is presented. An analytical closed‐form solution is obtained under a linear approximation. In the new framework given, the calculation of the open‐circuit voltage of the solar cell diode does not lead to unphysical results. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The effect of ultrasound on the Si‐SiO2 system
Authors: Kropman Daniel , Dolgov S.
Published: August 2012

The effect of ultrasonic treatment (UST) on the defect structure of the Si–SiO2 system by means of electron spin resonance (ESR), metallography, MOS capacitance technique, and secondary ions mass‐spectroscopy (SIMS) is presented. The non‐monotonous dependence of the defect densities on the US wave intensity has been observed. The influence of the UST frequency on the ESR signal intensity of the defect centers depended on the defect type and structure, and may be caused by dissipation of vibrational energy which is a function of the defect center type. The influence of the UST on the properties of the Si–SiO2 interface depends on the oxide thickness and crystallographic orientation. The density of point defects and absorbed impurities at the Si–SiO2 interface can be reduced and its electrical parameters improved by an appropriate choice of the UST and oxidation conditions. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A novel and efficient method combining acid leaching and thermal annealing for impurities removal from silicon intended for photovoltaic application
Authors: Khalifa M. , Hajji M. , Ezzaouia H.
Published: August 2012

The aim of this work is the purification of MG‐silicon powder using a method combining acid leaching and thermal annealing. It describes experiment carried out by using a tungsten lamps furnace (rapid thermal processing, RTP) to purify silicon powder under controlled atmosphere. This process enables to segregate the impurities to the surface of silicon powder where they can be extracted by partial dissolution in acids. Obtained silicon was investigated by Inductively Coupled Plasma Atomic Emission Spectrometry (ICP‐AES) method. Major impurities present in silicon powder were Al, K, Fe, Na, Ca, Mg and B. After purification the concentration of major impurities significantly decreased. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Fabrication and photoluminescence properties of Tb‐doped nitrogen‐rich silicon nitride films
Authors: An Y.‐T. , Labbé C. , Morales M. , Marie P. , Gourbilleau F.
Published: August 2012

Terbium (Tb) doped nitrogen‐rich silicon nitride thin films were prepared on [100] Si substrate by reactive magnetron co‐sputtering in pure nitrogen atmosphere. The microstructure and optical properties of the films were investigated by means of ellipsometric spectroscopy (ES), atomic force microscopy (AFM), X‐ray diffraction (XRD), Raman scattering and Fourier transform infrared (FTIR) spectroscopies as well as by photoluminescence (PL) experiments. A notable emission from Tb3+ ions was obtained for the as‐deposited layer, while the maximum intensity was found from 600 °C‐annealed sample. Deducing from PL excitation (PLE) analysis, a mechanism of excitation of Tb3+ ions was proposed: the band tail states of matrix play a minor role in the energy transfer process, while the host carriers across the optical gap acted as effective sensitizers for Tb3+ ions (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Unified analytical treatment for calculation of the two‐dimensional Franck–Condon factors using the duschinsky transformation
Authors: Mamedov B. A.
Published: August 2012

Including binomial expansion theorems, we present an analytical formula for calculating Franck–Condon (FC) factors of two‐dimensional (2D) harmonic oscillators including the Duschinsky effect. The FC principle has various practical applications in quantum modeling of electronic spectra of polyatomic molecules. The 2D FC factors are expressed through the binomial coefficients. Use of the memory of the computer for the calculation of binomial coefficients may extend the limits to large arguments for users and result in speeder calculation, should such limits be required in practice. Accurate numerical results are provided to validate the proposed algorithm. © 2012 Wiley Periodicals, Inc.
Quantized output feedback stabilization of uncertain systems with input nonlinearities via sliding mode control
Authors: Zheng Bo‐Chao , Yang Guang‐Hong
Published: August 2012

This paper is concerned with the quantized output feedback stabilization problem for a class of uncertain systems with nonsmooth nonlinearities in the actuator device via sliding mode control schemes. It is assumed that system signals are quantized before being transmitted through communication channels. First, a dynamical compensator is developed to estimate unmeasurable system state. Then a sliding surface, in the augmented space using the system output and the estimated state, is proposed, and an adaptive sliding mode control scheme with a static adjustment law of the quantization parameter is established. It is shown that the proposed quantized feedback control strategy is able to tackle parameter uncertainty, external disturbances, and nonsymmetric input nonlinearity simultaneously and guarantees the reachability of the sliding modes of the uncertain system. Finally, an example is given to verify the validity of the theoretical results. Copyright © 2012 John Wiley & Sons, Ltd.
Imaging and Measuring the Molecular Force of Lymphoma Pathological Cells Using Atomic Force Microscopy
Authors: Li Mi , Xiao Xiubin , Liu Lianqing , Xi Ning , Wang Yuechao , Dong Zaili , Zhang Weijing
Published: August 2012

Atomic force microscopy (AFM) provides a new technology to visualize the cellular topography and quantify the molecular interactions at nanometer spatial resolution. In this work, AFM was used to image the cellular topography and measure the molecular force of pathological cells from B‐cell lymphoma patients. After the fluorescence staining, cancer cells were recognized by their special morphological features and then the detailed topography was visualized by AFM imaging. The AFM images showed that cancer cells were much rougher than healthy cells. CD20 is a surface marker of B cells and rituximab is a monoclonal antibody against CD20. To measure the CD20‐rituximab interaction forces, the polyethylene glycol (PEG) linker was used to link rituximab onto the AFM tip and the verification experiments of the functionalized probe indicated that rituximab molecules were successfully linked onto the AFM tip. The CD20‐rituximab interaction forces were measured on about 20 pathological cells and the force measurement results indicated the CD20‐rituximab binding forces were mainly in the range of 110–120 pN and 130–140 pN. These results can improve our understanding of the topography and molecular force of lymphoma pathological cells. SCANNING 35:40‐46, 2013. © 2012 Wiley Periodicals, Inc.
Enzymatic Growth of Quantum Dots: Applications to Probe Glucose Oxidase and Horseradish Peroxidase and Sense Glucose
Authors: Saa Laura , Pavlov Valeri
Published: August 2012

Three innovative assays are developed for the detection of enzymatic activities of glucose oxidase (GOx) and horseradish peroxidase (HRP) by the generation of CdS quantum dots (QDs) in situ using non‐conventional enzymatic reactions. In the first assay, GOx catalyzes the oxidation of 1‐thio‐β‐D‐glucose to give 1‐thio‐β‐D‐gluconic acid. The latter is spontaneously hydrolyzed to β‐D‐gluconic acid and H2S, which in the presence of cadmium nitrate yields fluorescent CdS nanoparticles. In the second assay HRP catalyzes the oxidation of sodium thiosulfate with hydrogen peroxide generating H2S and consequently CdS QDs. The combination of GOx with HRP, allowed quantification of glucose in plasma by following growth of fluorescent QDs.
Species Management Benchmarking: Outcomes Over Outputs in a Changing Operating Environment
Authors: Hogg Carolyn J. , Hibbard Chris , Ford Claire , Embury Amanda
Published: August 2012

Species management has been utilized by the zoo and aquarium industry, since the mid‐1990s, to ensure the ongoing genetic and demographic viability of populations, which can be difficult to maintain in the ever‐changing operating environments of zoos. In 2009, the Zoo and Aquarium Association Australasia reviewed their species management services, focusing on addressing issues that had arisen as a result of the managed programs maturing and operating environments evolving. In summary, the project examined resourcing, policies, processes, and species to be managed. As a result, a benchmarking tool was developed (Health Check Report, HCR), which evaluated the programs against a set of broad criteria. A comparison of managed programs (n = 98), between 2008 and 2011, was undertaken to ascertain the tool's effectiveness. There was a marked decrease in programs that were designated as weak (37 down to 13); and an increase in excellent programs (24 up to 49) between the 2 years. Further, there were significant improvements in the administration benchmarking area (submission of reports, captive management plan development) across a number of taxon advisory groups. This HCR comparison showed that a benchmarking tool enables a program's performance to be quickly assessed and any remedial measures applied. The increases observed in program health were mainly due to increased management goals being attained. The HCR will be an ongoing program, as the management of the programs increases and goals are achieved, criteria will be refined to better highlight ongoing issues and ways in which these can be resolved. Zoo Biol. 32:230–237, 2013. © 2012 Wiley Periodicals, Inc.
The semi-classical expansion and resurgence in gauge theories: new perturbative, instanton, bion, and renormalon effects
Authors: Argyres Philip C. , Ünsal Mithat
Published: August 2012

Abstract

We study the dynamics of four dimensional gauge theories with adjoint fermions for all gauge groups, both in perturbation theory and non-perturbatively, by using circle compactification with periodic boundary conditions for the fermions. There are new gauge phenomena. We show that, to all orders in perturbation theory, many gauge groups are Higgsed by the gauge holonomy around the circle to a product of both abelian and nonabelian gauge group factors. Non-perturbatively there are monopole-instantons with fermion zero modes and two types of monopole-anti-monopole molecules, called bions. One type are magnetic bions which carry net magnetic charge and induce a mass gap for gauge fluctuations. Another type are neutral bions which are magnetically neutral, and their understanding requires a generalization of multi-instanton techniques in quantum mechanics — which we refer to as the Bogomolny-Zinn-Justin (BZJ) prescription — to compactified field theory. The BZJ prescription applied to bion-anti-bion topological molecules predicts a singularity on the positive real axis of the Borel plane (i.e., a divergence from summing large orders in peturbation theory) which is of order N times closer to the origin than the leading 4-d BPST instanton-anti-instanton singularity, where N is the rank of the gauge group. The position of the bion-anti-bion singularity is thus qualitatively similar to that of the 4-d IR renormalon singularity, and we conjecture that they are continuously related as the compactification radius is changed. By making use of transseries and Écalle’s resurgence theory we argue that a non-perturbative continuum definition of a class of field theories which admit semi-classical expansions may be possible.
Implementation of Self-Organizing Maps (SOM) to analyses of environmental parameters and phytoplankton biomass in a macrotidal estuary and artificial lake
Authors: Jahan Roksana , Choi Hyu Chang , Park Young Seuk , Park Young Cheol , Seo Ji Ho , Choi Joong Ki
Published: August 2012

Self-Organizing Maps (SOM) have been used for patterning and visualizing ten environmental parameters and phytoplankton biomass in a mactrotidal (>10 m) Gyeonggi Bay and artificial Shihwa Lake during 1986–2004. SOM segregated study areas into four groups and ten subgroups. Two strikingly alternative states are frequently observed: the first is a diverse non-eutrophic state designated by three groups (SOM 1–3), and the second is a eutrophic state (SOM 4: Shihwa Lake and Upper Gyeonggi Bay; summer season) characterized by enhanced nutrients (3 mg l−1 dissolved inorganic nitrogen, 0.1 mg l−1 PO4) that act as a signal and response to that signal as algal blooms (24 µg chlorophyll-a l−1). Bloom potential in response to nitrification is affiliated with high temperature (r = 0.26), low salinity (r = −0.40) and suspended solids (r = –0.27). Moreover, strong stratification in the Shihwa Lake has accelerated harmful algal blooms and hypoxia. The non-eutrophic states (SOM 1–3) are characterized by macro-tidal estuaries exhibiting a tolerance to pollution with nitrogen-containing nutrients and retarding any tendency toward stratification. SOM 1 (winter) is more distinct from SOM 4 due to higher suspended solids (>50 mg l−1) caused by resuspension that induces light limitation and low chlorophyll-a (<5 µg l−1). In addition, eutrophication-induced shifts in phytoplankton communities are noticed during all the seasons in Gyeonggi Bay. Overall, SOM showed high performance for visualization and abstraction of ecological data and could serve as an efficient ecological map that can specify blooming regions and provide a comprehensive view on the eutrophication process in a macrotidal estuary.
REVIVING CONFIDENCE
Authors: CONNELL CAROL M.
Published: August 2012

This paper examines two competing proposals for reforming and reviving confidence in the world monetary system, and the two economists, Robert Triffin and Fritz Machlup, who led the charge, one for centralized reserves, and the other for flexible exchange rates. Triffin would later claim that no one did more to ensure that floating exchange rates emerged the winner in the policy debate than Machlup because of his influence on academic economists and policy makers through the Bellagio Group conferences. The Bellagio Group conferences and Machlup’s leadership role are examined.
Lightning detection technology and applications of lightning data
Authors: Nag Amitabh , Holle Ronald L.
Published: August 2012

International Lightning Detection Conference/International Lightning Meteorology Conference; Broomfield, Colorado, 2–5 April 2012 More than 100 lightning scientists, meteorologists, and engineers attended the 22nd International Lightning Detection Conference (ILDC) and the 4th International Lightning Meteorology Conference (ILMC) sponsored by Vaisala Inc., in Broomfeld, Colo., this spring. Nearly half of the attendees were from outside the United States, making this event a truly international forum for discussing the science of lightning detection and its applications. ILDC has been held every other year for the past 17 years and took place annually before then. Traditionally, ILDC/ILMC has been a forum for designers and operators of lightning detection networks and users of network data to discuss the latest advances in technology and applications of lightning data for research and operational purposes, as well as technological innovations required to meet future operational challenges.
Droughts threaten Bornean rainforests
Authors: Bhattacharya Atreyee
Published: August 2012

At 130 million years old, the rainforests of Southeast Asia are the oldest in the world and home to thousands of species of plants and animals, some endemic to these forests. The rainforests also play important roles in modulating regional rainfall and in the global carbon cycle. However, since the 1960s, increased warming in the Indian Ocean and frequent El Niño events have reduced rainfall in the region by approximately 1.0% per decade. Furthermore, the Intergovernmental Panel for Climate Change predicts that over the 21st century, Southeast Asia will experience higher land temperatures, more droughts, and increased seasonality; that is, wet seasons during the fall will get wetter, and dry seasons during the spring will get drier. However, few studies in the past have investigated how trees in the southeastern Asian rainforests respond to droughts and climate change.
On the ionospheric source region of cold ion outflow
Authors: Li K. , Haaland S. , Eriksson A. , André M. , Engwall E. , Wei Y. , Kronberg E. A. , Fränz M. , Daly P. W. , Zhao H. , Ren Q. Y.
Published: August 2012

Recent studies have shown that low energy ions constitute a significant part of the total ion population in the Earth's magnetosphere. In this study, we have used a comprehensive data set with measurements of cold (total energy less than 70 eV) ion velocity and density to determine their source. This data set is derived from Cluster satellite measurements combined with solar wind and interplanetary magnetic field measurements and geomagnetic indices. By using the guiding center equation of motion, we were able to calculate the trajectories and thus determine the source region of the cold ions. Our results show that the polar cap region is the primary source for cold ions. We also found that the expansion and contraction of the polar cap as a consequence of changes in solar wind parameters were correlated with the source region size and intensity of the cold ion outflow. Elevated outflow fluxes near the nightside auroral zone and the dayside cusps during disturbed conditions suggest that energy and particle precipitation from the magnetosphere or directly from the solar wind can enhance the outflow of cold ions from the ionosphere.
High pressure ionic and molecular crystals of ammonia monohydrate within density functional theory
Authors: Griffiths Gareth I.G. , Misquitta Alston J. , Fortes A. Dominic , Pickard Chris J. , Needs Richard J.
Published: August 2012

A combination of first-principles density functional theory calculations and a search over structures is used to predict the stability of a proton-transfer modification of ammonia monohydrate with space group P4/nmm. The phase diagram is calculated with the Perdew-Burke-Ernzerhof (PBE) density functional, and the effects of a semi-empirical dispersion correction, zero point motion, and finite temperature are investigated. Comparison with MP2 and coupled cluster calculations shows that the PBE functional over-stabilizes proton transfer phases because too much electronic charge moves with the proton. This over-binding is partially corrected by using the PBE0 hybrid exchange-correlation functional, which increases the enthalpy of P4/nmm by about 0.6 eV per formula unit relative to phase I of ammonia monohydrate and shifts the transition to the proton transfer phase from the PBE pressure of 2.8 GPa to about 10 GPa. This is consistent with experiment as proton transfer phases have not been observed at pressures up to ∼9 GPa, while higher pressures have not yet been explored experimentally.
Full toroidal imaging of non-axisymmetric plasma material interaction in the National Spherical Torus Experiment divertor
Authors: Scotti Filippo , Roquemore A. L. , Soukhanovskii V. A.
Published: August 2012

A pair of two dimensional fast cameras with a wide angle view (allowing a full radial and toroidal coverage of the lower divertor) was installed in the National Spherical Torus Experiment in order to monitor non-axisymmetric effects. A custom polar remapping procedure and an absolute photometric calibration enabled the easier visualization and quantitative analysis of non-axisymmetric plasma material interaction (e.g., strike point splitting due to application of 3D fields and effects of toroidally asymmetric plasma facing components).
Development of a low-energy and high-current pulsed neutral beam injector with a washer-gun plasma source for high-beta plasma experiments
Authors: Ii Toru , Gi Keii , Umezawa Toshiyuki , Asai Tomohiko , Inomoto Michiaki , Ono Yasushi
Published: August 2012

We have developed a novel and economical neutral-beam injection system by employing a washer-gun plasma source. It provides a low-cost and maintenance-free ion beam, thus eliminating the need for the filaments and water-cooling systems employed conventionally. In our primary experiments, the washer gun produced a source plasma with an electron temperature of approximately 5 eV and an electron density of 5 × 1017 m−3, i.e., conditions suitable for ion-beam extraction. The dependence of the extracted beam current on the acceleration voltage is consistent with space-charge current limitation, because the observed current density is almost proportional to the 3/2 power of the acceleration voltage below approximately 8 kV. By optimizing plasma formation, we successfully achieved beam extraction of up to 40 A at 15 kV and a pulse length in excess of 0.25 ms. Its low-voltage and high-current pulsed-beam properties enable us to apply this high-power neutral beam injection into a high-beta compact torus plasma characterized by a low magnetic field.
Periodics orbits and $\mathcal {C}^{1}$C1-integrability in the planar Stark–Zeeman problem
Authors: de Bustos María T. , Guirao Juan L. G. , Vera Juan A. , Vigo–Aguiar Jesús
Published: August 2012

The aim of the present paper is to study the periodic orbits of a hydrogen atom under the effects of a circularly polarized microwave field and a static magnetic field orthogonal to the plane of polarization of the magnetic field via averaging theory. Moreover, the technique used for proving the existence of isolated periodic orbits allows us to provide information on the $\mathcal {C}^{1}$C1–integrability of this mechanic–chemical system.
Photoelectron velocity-map imaging signature of structural evolution of silver-doped lead Zintl anions
Authors: Xie Hua , Qin Zhengbo , Wu Xia , Tang Zichao , Jiang Ling
Published: August 2012

A set of silver-doped lead Zintl anions, Ag@Pbn− (n = 5–12), have been studied using photoelectron velocity-map imaging spectroscopy and quantum chemical calculation. The structures of Ag@Pbn− (n = 7–9, 11) built upon a square pyramid base, hitherto not considered, were assigned. Overall agreement between the experimental and calculated photoelectron spectra as well as vertical detachment energies allows for structural evolution to be established. The silver atom prefers to stay outside in the n ≤ 6 clusters and intends to be encapsulated by the lead atoms in n > 6. A stable endohedral cage with bicapped square antiprism structure is formed at n = 10, the endohedral structure of which persists for the larger clusters. Especially, these Ag@Pbn− anions have been found to undergo a transition between square pyramid and pentagonal pyramid molecular structures at n = 11.
Numerical simulation of operation modes in atmospheric pressure uniform barrier discharge excited by a saw-tooth voltage
Authors: Li Xuechen , Niu Dongying , Yin Zengqian , Fang Tongzhen , Wang Long
Published: August 2012

The characteristics of dielectric barrier discharge excited by a saw-tooth voltage are simulated in atmospheric pressure helium based on a one-dimensional fluid model. A stepped discharge is obtained per half voltage cycle with gas gap width less than 2 mm by the simulation, which is different to the pulsed discharge excited by a sinusoidal voltage. For the stepped discharge, the plateau duration increases with increasing the voltage amplitude and decreasing the gas gap. Therefore, uniform discharge with high temporal duty ratio can be realized with small gap through increasing the voltage amplitude. The maximal densities of both electron and ion appear near the anode and the electric field is almost uniformly distributed along the gap, which indicates that the stepped discharge belongs to a Townsend mode. In contrast to the stepped discharge with small gas gap, a pulsed discharge can be obtained with large gas gap. Through analyzing the spatial density distributions of electron and ion and the electric field, the pulsed discharge is in a glow mode. The voltage-current (V-I) characteristics are analyzed for the above mentioned discharges under different gas gaps, from which the different discharge modes are verified.
Role of ultra thin pseudomorphic InP layer to improve the high-k dielectric/GaAs interface in realizing metal-oxide-semiconductor capacitor
Authors: Kundu Souvik , Halder Nripendra N. , Biswas D. , Banerji P. , Shripathi T. , Chakraborty S.
Published: August 2012

In this article, we report GaAs metal-oxide-semiconductor (MOS) capacitors with a metal organic chemical vapor deposited ultrathin (1.5 nm) pseudomorphic InP interface passivation layer (IPL) and a thin (5 nm) ZrO2 high-k dielectric. Reduction of the surface states on InP passivated GaAs surfaces was observed from the photoluminescence study. The x-ray photoelectron spectra confirmed the dramatic reduction of GaAs native oxides (Ga-O and As-O) from the interface of ZrO2 and p-GaAs, implying that the Fermi level at the high-k/GaAs interface can be unpinned with good interface quality. As a result, very low values of interface trap density (1.1 × 1011 cm−2 eV−1) and hysteresis (8.21 mV) were observed. The same was done for directly deposited ZrO2 on GaAs surface to understand the efficacy of InP interface passivation layer on GaAs MOS devices. A systematic capacitance-voltage and current density-voltage studies were performed on bothAl/ZrO2/InP/p-GaAs and Al/ZrO2/p-GaAs structures. It was found that insertion of 1.5 nm InP ultrathin layer in-between ZrO2 and GaAs improves the essential parameters of GaAs MOS such as dielectric constant, frequency dispersion, leakage current, etc. The dielectric reliability has been studied with constant voltage stressing. A very small flatband voltage shift with stress time was observed in InP passivated GaAs MOS capacitors.
“People Who Deserve It”: Jozef Tiso and the Presidential Exemption
Authors: Ward James Mace
Published: August 2012

Between March and October of 1942, Slovakia deported the majority of its Jews to extermination camps in German-occupied Poland. Since then, critics and apologists of the nominally independent Nazi satellite state have argued bitterly over who was to blame. Did the Slovaks act voluntarily or under German pressure? If the latter, were they in any position to do otherwise? With equal vigor, the two sides have clashed over whether the Slovaks realized they were participating in genocide, whether they acted to limit or stop the deportations once the truth came out, and whether, compared with other German-occupied or German-allied countries, Slovakia succeeded in saving a relatively high percentage of its Jewry.
Distribution, Size, and Origin of Juvenile Chinook Salmon in Shallow-Water Habitats of the Lower Columbia River and Estuary, 2002–2007
Authors: Roegner G. Curtis , McNatt Regan , Teel David J. , Bottom Daniel L.
Published: August 2012

We monitored fish assemblages monthly at estuarine and tidal freshwater sites in the lower Columbia River and estuary from January 2002 through September 2007 in order to identify specific salmon stocks and migration stages that may benefit from habitat restoration initiatives. We report landscape-scale and seasonal variation in abundance, size, hatchery production (based on adipose fin clips), and genetic stock of origin of juvenile Chinook salmon Oncorhynchus tshawytscha. From fish implanted with coded wire tags (CWTs), we also determined the sites of release and inferred migration patterns. Chinook salmon were found in diverse life history stages and forms, including fry migrants, fingerlings, and (fewer) yearlings. Abundance increased in February and decreased in August, but salmon were present in all months each year. Spatial gradients in abundance and size were strong, with fewer but larger fish in brackish than in tidal freshwater zones. Overall, 30% of the Chinook salmon measured were fry (≤60 mm) that were likely naturally produced fish. These occurred at higher mean monthly proportions in tidal freshwater than in estuarine zones. In contrast, most larger fish were probably raised in hatcheries. Genetic stock assessment revealed that the majority of the Chinook salmon analyzed were from fall-run stock groups originating in the lower Columbia River, with 15% originating from other stock groups. Of these minority contributors, about 6% were identified as upper Columbia River summer–fall-run Chinook salmon while seven other stock groups accounted for the remainder, including 3% from transplants originating in southern Oregon's Rogue River. Recaptures of tagged fish revealed maximum migration times of 143 d for subyearlings and 52 d for yearlings, and both CWT and genetic data indicated that fall Chinook salmon from coastal rivers occasionally entered the estuary. These data demonstrated a widespread temporal and spatial distribution of subyearling Chinook salmon in shallow-water habitats of the lower Columbia River and estuary.

Received June 28, 2011; accepted February 28, 2012
Why nature chose phosphate to modify proteins
Authors: Hunter Tony
Published: August 2012

The advantageous chemical properties of the phosphate ester linkage were exploited early in evolution to generate the phosphate diester linkages that join neighbouring bases in RNA and DNA (Westheimer 1987
Science
235
, 1173–1178). Following the fixation of the genetic code, another use for phosphate ester modification was found, namely reversible phosphorylation of the three hydroxyamino acids, serine, threonine and tyrosine, in proteins. During the course of evolution, phosphorylation emerged as one of the most prominent types of post-translational modification, because of its versatility and ready reversibility. Phosphoamino acids generated by protein phosphorylation act as
new
chemical entities that do not resemble any natural amino acid, and thereby provide a means of diversifying the chemical nature of protein surfaces. A protein-linked phosphate group can form hydrogen bonds or salt bridges either intra- or intermolecularly, creating stronger hydrogen bonds with arginine than either aspartate or glutamate. The unique size of the ionic shell and charge properties of covalently attached phosphate allow specific and inducible recognition of phosphoproteins by phosphospecific-binding domains in other proteins, thus promoting inducible protein–protein interaction. In this manner, phosphorylation serves as a switch that allows signal transduction networks to transmit signals in response to extracellular stimuli.
Mutational properties of amino acid residues: implications for evolvability of phosphorylatable residues
Authors: Creixell Pau , Schoof Erwin M. , Tan Chris Soon Heng , Linding Rune
Published: August 2012

As François Jacob pointed out over 30 years ago, evolution is a tinkering process, and, as such, relies on the genetic diversity produced by mutation subsequently shaped by Darwinian selection. However, there is one implicit assumption that is made when studying this tinkering process; it is typically assumed that all amino acid residues are equally likely to mutate or to result from a mutation. Here, by reconstructing ancestral sequences and computing mutational probabilities for all the amino acid residues, we refute this assumption and show extensive inequalities between different residues in terms of their mutational activity. Moreover, we highlight the importance of the genetic code and physico-chemical properties of the amino acid residues as likely causes of these inequalities and uncover serine as a mutational hot spot. Finally, we explore the consequences that these different mutational properties have on phosphorylation site evolution, showing that a higher degree of evolvability exists for phosphorylated threonine and, to a lesser extent, serine in comparison with tyrosine residues. As exemplified by the suppression of serine's mutational activity in phosphorylation sites, our results suggest that the cell can fine-tune the mutational activities of amino acid residues when they reside in functional protein regions.
Psychometric Properties of the Existence Subscale of the Purpose in Life Questionnaire for Chinese Adolescents in Hong Kong
Authors: Law Ben M. F.
Published: August 2012

The current study aims to test the psychometric properties of the Existence Subscale of the Purpose in Life Questionnaire (EPIL) for early adolescence. The Purpose in Life Questionnaire (PIL), originally created by Craumbaugh and Maholick, is a 20-item scale measuring different dimensions of life purposes. The current study selected seven items representative of the existence dimension to form another scale, the EPIL. The analysis was based on 2842 early adolescents, ranging from 11 to 14 years old. Principal axis factoring found one factor, with 60% variance being explained. Cronbach’s alpha for the EPIL was 0.89, which was high. The factor structure was stable across genders. Criterion-related validity was determined when the scale was used to differentiate volunteers and nonvolunteers. Construct validity was found when the scale was associated with life satisfaction. The results give support to the fact that the EPIL could be used alone to measure the psychological well-being of early adolescents and the appropriateness of the EPIL in adolescent research.
Antibiotic Susceptibility Profile ofAeromonasSpecies Isolated from Wastewater Treatment Plant
Authors: Igbinosa Isoken H. , Okoh Anthony I.
Published: August 2012

This study assessed the prevalence of antibiotic-resistantAeromonasspecies isolated from Alice and Fort Beaufort wastewater treatment plant in the Eastern Cape Province of South Africa. Antibiotic susceptibility was determined using the disc diffusion method, and polymerase chain reaction (PCR) assay was employed for the detection of antibiotics resistance genes. Variable susceptibilities were observed against ciprofloxacin, chloramphenicol, nalidixic acid, gentamicin, minocycline, among others.Aeromonasisolates from both locations were 100% resistant to penicillin, oxacillin, ampicillin, and vancomycin. Higher phenotypic resistance was observed in isolates from Fort Beaufort compared to isolates from Alice. Class Apse1β-lactamase was detected in 20.8% of the isolates with a lower detection rate of 8.3% forblaTEMgene. Class 1 integron was present in 20.8% ofAeromonasisolates while class 2 integron andTetCgene were not detected in any isolate. The antibiotic resistance phenotypes observed in the isolates and the presence ofβ-lactamases genes detected in some isolates are of clinical and public health concern as this has consequences for antimicrobial chemotherapy of infections associated withAeromonasspecies. This study further supports wastewater as potential reservoirs of antibiotic resistance determinants in the environment.
Prognostic significance of pituitary tumour‐transforming gene‐binding factor (PBF) expression in papillary thyroid carcinoma
Authors: Hsueh Chuen , Lin Jen‐Der , Chang Yu‐Sun , Hsueh Swei , Chao Tzu‐Chieh , Yu Jau‐Song , Jung Shih‐Ming , Tseng Ngan‐Ming , Sun Jui‐Hung , Kuo Shau‐Yun , Ueng Shir‐Hwa
Published: August 2012

Background

Pituitary tumour‐transforming gene (PTTG)‐binding factor (PBF), originally known as PTTG1 interacting protein (PTTG1IP), has been found to be significantly increased in well‐differentiated thyroid cancer and independently associated with early tumour recurrence.

Objective

To assess the prognostic significance of PBF expression in a large cohort of papillary thyroid carcinoma (PTC) patients with a long‐term follow‐up.

Design and patients

Retrospective analysis of PBF expression in PTC cases at different stages and correlate it with various clinicopathological parameters and patient survival. Subjects included 153 patients who received a thyroid operation for PTC at Chang Gung Memorial Hospital between 1991 and 2000. All patients had a complete follow‐up till the end of 2010.

Measurements

Immunohistochemical study for PBF expression on tissue sections from tumour specimens. Bond automated machine (Leica Microsystems, Germany) with a polyclonal rabbit anti‐PBF antibody (LifeSpan BioSciences, LS‐C118942, Seattle, WA, USA) was used. SPSS 13.0 for Windows (SPSS Inc, Chicago, IL, USA) was used for all statistical analyses.

Results

High PBF expression was significantly correlated with age (P = 0·0298), distant metastases at diagnosis (P = 0·0139), tumour multicentricity (P = 0·0035), TNM stage (P = 0·0103), locoregional recurrence (P = 0·0410) and disease‐specific mortality (P = 0·0064). The expression level of PBF was significantly correlated with disease‐specific survival (P = 0·0065). Cox regression analysis showed that age, tumour size and PBF expression were independent prognostic indicators (P = 0·0097, P = 0·0021 and P = 0·0179).

Conclusion

PBF expression may be a promising biomarker for prognostic and therapeutic purpose. More large‐scale studies are needed to clarify its potential usefulness.
Determination of the uncertainty for the thermal conductivity obtained as a function of the moisture content for several foodstuffs
Authors: da Silva Wilton Pereira , e Silva Cleide M. D. P. S. , Precker Jürgen Wolfgang , Duarte Maria Elita Martins
Published: August 2012

Many times, when an experimental result is communicated, the uncertainty is omitted, particularly in the case in which the parameter of interest is determined by curve fitting. This article presents a review study to include an uncertainty to the parameter of interest, obtained by fitting of a straight line to an experimental data set, supposing that systematic errors can be neglected. This study is applied to the determination of expressions for the thermal conductivity of food products, supposing a constant mean temperature. In this case, in general, the thermal conductivity is a linear function of the moisture content (wb). Expressions of the thermal conductivity were obtained for several foodstuffs, according to the recommendation of the International Organization for Standardization. Thus, for a given moisture content, the obtained expressions enable to determine the value for the thermal conductivity, as well as its uncertainty, for a stipulated confidence limit.
Antioxidant properties of different milk fermented with lactic acid bacteria and yeast
Authors: Parrella Alfredo , Caterino Emanuela , Cangiano Margherita , Criscuolo Emma , Russo Chiara , Lavorgna Margherita , Isidori Marina
Published: August 2012

The antioxidant properties of nine different samples of freshly drawn, pasteurised and UHT milk were examined before and after fermentation with several lactobacilli, individually and in combination with the yeast Saccharomyces boulardii. The results showed no statistical differences for the content in proteins, fats and carbohydrates of the different milk. The antioxidant properties of the unfermented milk were positively affected by the thermal treatment. All samples of fermented milk had a greater antioxidant activity than unfermented but only for the freshly drawn milk that increase was significantly different. The co‐incubation of lactobacilli with the yeast determined a stronger antioxidant activity especially for the freshly drawn milk. The stability of the tested strains during storage in standard conditions was determined in UHT fermented milk to enable a possible use in probiotic food production. The results showed that the yeast incubated with lactobacilli determined an improvement of the viability of bacteria.
Characterisation of pear distillates from wild and cultivated varieties in Sardinia
Authors: Versini Giuseppe , Franco Mario A. , Moser Sergio , Manca Gavina
Published: August 2012

The aroma fraction of Italian distillates of wild (Pyrus amygidaliformis, Vill., namely ‘Pirastru’) and cultivated (Pyrus communis, L. cvs. ‘Coscia’, ‘Precoce di Fiorano’ and ‘Butirru de Austu’) pear varieties grown in the northern part of the island of Sardinia was investigated. Distillates from fermented mashes were obtained from the same producer and, in most cases, for 3 years following the same production process. Aroma analyses were performed by GC‐FID and GC‐MS techniques with direct GC injection of full proof distillates. Differences were found in the aromatic profile of all the distillates depending on their varietal origin. Wild Pirastru pear distillates were the richest in isoeugenol (0.186 g hL−1 a.a.), ethyl benzoate (0.388 g hL−1 a.a.) and ethyl phenylacetate (0.12 g hL−1 a.a.) but the poorest in 1‐hexanol (2.69 g hL−1 a.a.), n‐hexyl acetate (0.07 g hL−1 a.a.), Σ‐farnesene isomers (0.80 g hL−1 a.a.) and citronellol (0.007 g hL−1 a.a.). Pirastru distillates were also the poorest in methyl and ethyl unsaturated decanoate isomers, the so‐called Williams pear esters (0.002 g hL−1 a.a.). On the contrary, these compounds that characterise the aroma of Williams pear distillates were abundant in Coscia spirits (1.032 g hL−1 a.a.). The latter, together with Precoce di Fiorano, were rich in farnesene isomers (6.48 and 9.26 g hL−1 a.a. respectively). Evaluation of the data by univariate (anova and Kruskal–Wallis) and multivariate (PCA and HCA) statistical analyses revealed that some components (the classes of acetates, farnesene isomers, methyl and ethyl unsaturated decanoate esters and citronellol) are relevant in discriminating the distillates according to variety.
Sex Steroid Levels and AD‐Like Pathology in 3xTgAD Mice
Authors: Overk C. R. , Perez S. E. , Ma C. , Taves M. D. , Soma K. K. , Mufson E. J.
Published: August 2012

Decreases in testosterone and 17β‐oestradiol (E2) are associated with an increased risk for Alzheimer's disease (AD), which has been attributed to an increase in β‐amyloid and tau pathological lesions. Although recent studies have used transgenic animal models to test the effects of sex steroid manipulations on AD‐like pathology, almost none have systematically characterised the associations between AD lesions and sex steroid levels in the blood or brain in any mutant model. The present study evaluated age‐related changes in testosterone and E2 concentrations, as well as androgen receptor (AR) and oestrogen receptor (ER) α and β expression, in brain regions displaying AD pathology in intact male and female 3xTgAD and nontransgenic (ntg) mice. We report for the first time that circulating and brain testosterone levels significantly increase in male 3xTgAD mice with age, but without changes in AR‐immunoreactive (IR) cell number in the hippocampal CA1 or medial amygdala. The age‐related increase in hippocampal testosterone levels correlated positively with increases in the conformational tau isoform, Alz50. These data suggest that the over‐expression of human tau up‐regulate the hypothalamic‐pituitary‐gonadal axis in these mice. Although circulating and brain E2 levels remained stable with age in both male and female 3xTgAD and ntg mice, ER‐IR cell number in the hippocampus and medial amygdala decreased with age in female transgenic mice. Furthermore, E2 levels were significantly higher in the hippocampus than in serum, suggesting local production of E2. Although triple transgenic mice mimic AD‐like pathology, they do not fully replicate changes in human sex steroid levels, and may not be the best model for studying the effects of sex steroids on AD lesions.