bluuebunny/crossref_metadata_2025 huggingface dataset:
Impact of stochastic fluctuations in storage‐discharge relations on streamflow distributions
Authors: Suweis S. , Bertuzzo E. , Botter G. , Porporato A. , Rodriguez‐Iturbe I. , Rinaldo A.
Published: March 2010

In this paper we extend recent theoretical results on the structure of the probability density function of streamflows forced by stochastic rainfall sequences. Our extension is aimed at incorporating an additional, independent source of variability assumed to describe noisy constitutive storage‐discharge relations, thought of as portraying phenomena like transient connectivity, differential activation of preferential flow paths, or macroscopic effects of spatially heterogeneous and hysteretic subsurface properties. We first show by numerical simulation that a colored noise superposed to the storage‐discharge relation does not appreciably affect the overall characterization of the storage distribution. Streamflows prove more sensitive to such noise. This effect is examined by including stochasticity directly into the streamflow generation processes in the form of Gaussian multiplicative noise affecting the discharge equation of a linear reservoir. Under the above conditions, exact analytical probability distributions for the streamflow are derived. The results show that the streamflow regimes, roughly termed wet and dry to describe perennial or ephemeral streamflow regimes, are peculiarly modified by the noise and are controlled by the ratio between the subsubsurface percolation frequency, by the inverse of the mean residence time of subsurface flow, and by the noise strength. Our results suggest new and significant noise‐induced phenomena, with notable ecological implications in particular for possible shifts from perennial to ephemeral regimes.
Wnt signalling and the control of cellular metabolism
Authors: Sethi Jaswinder K. , Vidal-Puig Antonio
Published: March 2010

At the cellular level, the biological processes of cell proliferation, growth arrest, differentiation and apoptosis are all tightly coupled to appropriate alterations in metabolic status. In the case of cell proliferation, this requires redirecting metabolic pathways to provide the fuel and basic components for new cells. Ultimately, the successful co-ordination of cell-specific biology with cellular metabolism underscores multicellular processes as diverse as embryonic development, adult tissue remodelling and cancer cell biology. The Wnt signalling network has been implicated in all of these areas. While each of the Wnt-dependent signalling pathways are being individually delineated in a range of experimental systems, our understanding of how they integrate and regulate cellular metabolism is still in its infancy. In the present review we reassess the roles of Wnt signalling in functionally linking cellular metabolism to tissue development and function.
School-Based Practice in a Climate of Budget Constraints: An Interview With Barbara Moore
Authors: Rudebusch Judy
Published: March 2010

This article provides an overview of public school funding mechanisms and the interface between local, state, and federal funding streams. Information about the impact of a weak economy on school funding is explored with suggestions for speech-language pathologists to use in times of budget crises to evaluate, prioritize, and improve quality of services for students.
Advocating for Change in Your State or Local School District: A Successful Game Plan
Authors: Deppe Janet
Published: March 2010

All of us remember a time when we convinced our spouse to let our son try out for the football team, helped our daughter prepare and practice her speech for the student council election, pleaded with a teacher about a grade or assignment, or helped a parent or friend negotiate the health care system to get the right medical treatment.
Maids, Machines and Morality in Brazilian Homes
Authors: Silva Elizabeth
Published: March 2010

This paper engages with debates about the increasing use of paid domestic labour in Europe and the USA, contributing with a reflection about the case of Brazil. Relations of gender, class and race are considered in the deployment of maids for housework, the patterns of consumption of household technologies and the moral reasoning of daily living with hierarchical divisions within the home. The paper considers some parallels between the Brazilian context and that of more developed countries and also the specificity of Brazil. Based on participant observation, secondary data and an ethnographic study, rich empirical data is weaved through to discuss material and moral dimensions of domestic labour and care. How does the availability of cheap domestic labour configure relations of inequality? How are social differences in the home lived with and justified? The exploration of the Brazilian case illuminates some of the problems, contradictions and possible consequences of wealthier households benefitting from the displacement of poor women that is currently happening through international migration. The paper argues that in Brazil the deflecting of tensions in gender divisions of labour in households onto a subordinate person has affected relations of equality between women and men and also the patterns of technological innovation to facilitate housework. These are outcomes to be guarded against in Europe and the United States in face of the current trends in ‘global woman’ relations.
A Migrant Ethic of Care? Negotiating Care and Caring among Migrant Workers in London's Low-Pay Economy
Authors: Datta Kavita , McIlwaine Cathy , Evans Yara , Herbert Joanna , May Jon , Wills Jane
Published: March 2010

A care deficit is clearly evident in global cities such as London and is attributable to an ageing population, the increased employment of native-born women, prevalent gender ideologies that continue to exempt men from much reproductive work, as well as the failure of the state to provide viable alternatives. However, while it is now acknowledged that migrant women, and to a lesser extent, migrant men, step in to provide care in cities such as London, there is less research on how this shapes the nature, politics and ethics of care. Drawing upon empirical research with low-paid migrant workers employed as domiciliary care providers in London, this paper explores the emergence of a distinct migrant ethic of care that is critically shaped by the caring work that migrant women and men perform.
Photoinitiation study of Irgacure 784 in an epoxy resin photopolymer
Authors: Sabol Dušan , Gleeson Michael R. , Liu Shui , Sheridan John T.
Published: March 2010

A deeper understanding of the processes, which occur during free radical photopolymerization, is necessary in order to develop a fully comprehensive model, which represents their behavior during exposure. One of these processes is photoinitiation, whereby a photon is absorbed by a photosensitizer producing free radicals, which can initiate polymerization. These free radicals can also participate in polymer chain termination (primary termination), and it is therefore necessary to understand their generation in order to predict the temporally varying kinetic effects present during holographic grating formation. In this paper, a study of the photoinitiation mechanisms of Irgacure 784 photosensitizer, in an epoxy resin matrix, is presented. We report our experimental results and present a theoretical model to predict the physically observed behavior.
All-optical switching with bacteriorhodopsin protein coated microcavities and its application to low power computing circuits
Authors: Roy Sukhdev , Prasad Mohit , Topolancik Juraj , Vollmer Frank
Published: March 2010

We show all-optical switching of an input infrared laser beam at 1310 nm by controlling the photoinduced retinal isomerization to tune the resonances in a silica microsphere coated with three bacteriorhodopsin (BR) protein monolayers. The all-optical tunable resonant coupler re-routes the infrared beam between two tapered fibers in 50 μs using a low power (<200 μW) green (532 nm) and blue (405 nm) pump beams. The basic switching configuration has been used to design all-optical computing circuits, namely, half and full adder/subtractor, de-multiplexer, multiplexer, and an arithmetic unit. The design requires 2n−1 switches to realize n bit computation. The designs combine the exceptional sensitivities of BR and high-Q microcavities and the versatile tree architecture for realizing low power circuits and networks (approximately mW power budget). The combined advantages of high Q-factor, tunability, compactness, and low power control signals, with the flexibility of cascading switches to form circuits, and reversibility and reconfigurability to realize arithmetic and logic functions, makes the designs promising for practical applications. The designs are general and can be implemented (i) in both fiber-optic and integrated optic formats, (ii) with any other coated photosensitive material, or (iii) any externally controlled microresonator switch.
Electronic temperatures, densities, and plasma x-ray emission of a 14.5 GHz electron-cyclotron resonance ion source
Authors: Gumberidze A. , Trassinelli M. , Adrouche N. , Szabo C. I. , Indelicato P. , Haranger F. , Isac J.-M. , Lamour E. , Le Bigot E.-O. , Mérot J. , Prigent C. , Rozet J.-P. , Vernhet D.
Published: March 2010

We have performed a systematic study of the bremsstrahlung emission from the electrons in the plasma of a commercial 14.5 GHz electron-cyclotron resonance ion source. The electronic spectral temperature and the product of ionic and electronic densities of the plasma are measured by analyzing the bremsstrahlung spectra recorded for several rare gases (Ar, Kr, and Xe) as a function of the injected power. Within our uncertainty, we find an average temperature of ≈48 keV above 100 W, with a weak dependency on the injected power and gas composition. Charge state distributions of extracted ion beams have been determined as well, providing a way to disentangle the ionic density from the electronic density. Moreover x-ray emission from highly charged argon ions in the plasma has been observed with a high-resolution mosaic-crystal spectrometer, demonstrating the feasibility for high-precision measurements of transition energies of highly charged ions, in particular, of the magnetic dipole (M1) transition of He-like of argon ions.
Rotational stabilization of resistive wall modes in ITER advanced tokamak scenarios
Authors: Zheng L. J. , Kotschenreuther M. T. , Van Dam J. W.
Published: March 2010

Rotational stabilization of n=1 resistive wall modes in ITER advanced scenarios [K. Ikeda, Nucl. Fusion 47 (2007)] is investigated, where n is the toroidal mode number. In particular, we present numerical results for the ITER strongly reversed shear case, in comparison to the weakly reversed shear case. The rotation frequency is assumed to be modestly low. Our investigation employs the adaptive eigenfunction independent solution-kinetic (AEGIS-K) code [L. J. Zheng et al., “AEGIS-K code for linear kinetic analysis of toroidally axisymmetric plasma stability,” J. Comput. Phys. (to be published)], which provides a fully kinetic (nonhybrid) and self-consistent (nonperturbative) description. AEGIS-K includes wave-particle resonances, shear Alfvén continuum damping, trapped particle effects, and parallel electric effects, but not finite Larmor radius effects. In the case without rotation and kinetic effects included, we find that the strongly reversed shear configuration is more favorable for perfectly conducting wall stabilization of resistive wall modes, in that it has a higher conducting wall beta limit than the weakly reversed shear case. With sufficient rotation, the strongly reversed shear case can also achieve a higher beta limit for completely suppressing the resistive wall modes. However, the marginal rotation frequency required for complete resistive wall mode stabilization in the strongly reversed shear case is about twice as high as that required for the weakly reversed shear case.
Nonequilibrium, steady-state electron transport with N-representable density matrices from the anti-Hermitian contracted Schrödinger equation
Authors: Rothman Adam E. , Mazziotti David A.
Published: March 2010

We study molecular conductivity for a one-electron, bath-molecule-bath model Hamiltonian. The primary quantum-mechanical variable is the one-electron reduced density matrix (1-RDM). By identifying similarities between the steady-state Liouville equation and the anti-Hermitian contracted Schrödinger equation (ACSE) [D. A. Mazziotti, Phys. Rev. A 75, 022505 (2007)], we develop a way of enforcing nonequilibrium, steady-state behavior in a time-independent theory. Our results illustrate the relationship between current and voltage in molecular junctions assuming that the total number of electrons under consideration can be fixed across all driving potentials. The impetus for this work is a recent study by Subotnik et al. that also uses the 1-RDM to study molecular conductivity under different assumptions regarding the total number of electrons [J. E. Subotnik et al., J. Chem. Phys. 130, 144105 (2009)]. Unlike calculations in the previous study, our calculations result in 1-RDMs that are fully N-representable. The present work maintains N-representability through a bath-bath mixing that is related to a time-independent relaxation of the baths in the absence of the molecule, as governed by the ACSE. A lack of N-representability can be important since it corresponds to occupying energy states in the molecule or baths with more than one electron or hole (the absence of an electron) in violation of the Pauli principle. For this reason the present work may serve as an important, albeit preliminary, step in designing a 2-RDM/ACSE method for studying steady-state molecular conductivity with an explicit treatment of electron correlation.
Calculating Kelvin force microscopy signals from static force fields
Authors: Borowik Łukasz , Kusiaku Koku , Théron Didier , Mélin Thierry
Published: March 2010

We present an analytical formula to achieve numerical simulations of Kelvin force microscopy (KFM) signals from static force fields, which can be employed to describe amplitude-modulation or frequency-modulation KFM, as well as simultaneous topography and KFM modes for which the tip probe exhibits a nonzero oscillation during KFM imaging. This model is shown to account for side-capacitance and nonlinear effects taking place in KFM experiments, and can therefore be used conveniently to extract quantitative information from KFM experiments at the nanoscale.
Carrier transport and sensitivity issues in heterojunction with intrinsic thin layer solar cells on N-type crystalline silicon: A computer simulation study
Authors: Rahmouni M. , Datta A. , Chatterjee P. , Damon-Lacoste J. , Ballif C. , Roca i Cabarrocas P.
Published: March 2010

Heterojunction with intrinsic thin layer or “HIT” solar cells are considered favorable for large-scale manufacturing of solar modules, as they combine the high efficiency of crystalline silicon (c-Si) solar cells, with the low cost of amorphous silicon technology. In this article, based on experimental data published by Sanyo, we simulate the performance of a series of HIT cells on N-type crystalline silicon substrates with hydrogenated amorphous silicon (a-Si:H) emitter layers, to gain insight into carrier transport and the general functioning of these devices. Both single and double HIT structures are modeled, beginning with the initial Sanyo cells having low open circuit voltages but high fill factors, right up to double HIT cells exhibiting record values for both parameters. The one-dimensional numerical modeling program “Amorphous Semiconductor Device Modeling Program” has been used for this purpose. We show that the simulations can correctly reproduce the electrical characteristics and temperature dependence for a set of devices with varying I-layer thickness. Under standard AM1.5 illumination, we show that the transport is dominated by the diffusion mechanism, similar to conventional P/N homojunction solar cells, and tunneling is not required to describe the performance of state-of-the art devices. Also modeling has been used to study the sensitivity of N-c-Si HIT solar cell performance to various parameters. We find that the solar cell output is particularly sensitive to the defect states on the surface of the c-Si wafer facing the emitter, to the indium tin oxide/P-a-Si:H front contact barrier height and to the band gap and activation energy of the P-a-Si:H emitter, while the I-a-Si:H layer is necessary to achieve both high Voc and fill factor, as it passivates the defects on the surface of the c-Si wafer. Finally, we describe in detail for most parameters how they affect current transport and cell properties.
The effect of thermal oxidation on laser-induced photoelectron emission during tensile deformation of polycrystalline aluminum
Authors: Cai M. , Ricker R. E. , Levine L. E. , Langford S. C. , Dickinson J. T.
Published: March 2010

Many metals emit electrons when exposed to UV radiation (photon energies 4 to 8 eV). Deformation can significantly affect the intensity of these emissions. In the case of reactive metals, these emissions are also altered by the presence of surface oxides. We have characterized the effect of thermal oxides on laser-induced photoelectron emission from commercially pure polycrystalline aluminum with a view toward using these emissions as a probe of deformation processes. The thickness of oxides produced by a range of annealing treatments in air was determined by x-ray photoelectron spectroscopy. Time-of-flight measurements on photoelectrons from these surfaces under 248 nm irradiation (5 eV photons) show two peaks: a fast peak which we attributed to electrons from metallic aluminum, and a slower peak, which may be due to electrons from interface states. Surface oxide films of sufficient thickness attenuate both peaks. We show that the sensitivity of the photoelectron signals to deformation varies with thermal oxidation pretreatments and oxide film thickness and that with the appropriate oxide thickness the total photoelectron intensity becomes a sensitive probe of deformation-related processes during tensile testing.
Magnetic-field modulated exciton-exciton interaction in semiconductor microcavities
Authors: Zhang Yongyou , Shi Li-jie , Jin Guojun , Zou Bingsuo
Published: March 2010

We study the quantum-well magnetoexcitons by the variational method in the strong coupling regime of excitons with microcavity photons. In such strong coupling regime, we find that the coupling between the exciton internal state and center of mass motion can be neglected. Through the calculations, we find that the magnetic field can reduce the exciton exchange interaction to 30% as Lw=30 nm with Lw being the quantum well width. This is in contrast to the magnetic-field enhancement in the exciton Rabi splitting. In this work, we obtain that a magnetic field can enhance the exciton Rabi splitting up to 1.6 times in the case of Lw=30 nm. They both originate from the local enhancement in the exciton internal state due to the magnetic field. In addition, we analyze the behavior of the magnetic response of the exciton energy, Rabi splitting, and exchange interaction in manipulating the polariton parametric scattering, and widening the microcavity applications.
Oxygen-oxygen correlations in liquid water: Addressing the discrepancy between diffraction and extended x-ray absorption fine-structure using a novel multiple-data set fitting technique
Authors: Wikfeldt Kjartan Thor , Leetmaa Mikael , Mace Amber , Nilsson Anders , Pettersson Lars G. M.
Published: March 2010

The first peak of the oxygen-oxygen pair-correlation function (O–O PCF) is a critical measure of the first coordination-shell distances in liquid water. Recently, a discrepancy has been uncovered between diffraction and extended x-ray absorption fine-structure (EXAFS) regarding the height and position of this peak, where EXAFS gives a considerably more well-defined peak at a shorter distance compared to the diffraction results. This discrepancy is here investigated through a novel multiple-data set structure modeling technique, SpecSwap-RMC, based on the reverse Monte Carlo (RMC) method. Fitting simultaneously to both EXAFS and a diffraction-based O–O PCF shows that even though the reported EXAFS results disagree with diffraction, the two techniques can be reconciled by taking into account a strong contribution from the photoelectron scattering focusing effect in EXAFS originating from nearly linear hydrogen bonds. This many-body contribution, which is usually neglected in RMC modeling of EXAFS data, is included in the fits by precomputing and storing EXAFS signals from real-space multiple-scattering calculations on a large number of unique water clusters. On the other hand, fitting also the O–O PCF from diffraction is seen to enhance the amount of structural disorder in the joint fit. Thus, both structures containing nearly linear hydrogen bonds and local structural disorder are important to reproduce diffraction and EXAFS simultaneously. This work also illustrates a few of many possible uses of the SpecSwap-RMC method in modeling disordered materials, particularly for fitting computationally demanding techniques and combining multiple data sets.
Pulsed-power-driven cylindrical liner implosions of laser preheated fuel magnetized with an axial field
Authors: Slutz S. A. , Herrmann M. C. , Vesey R. A. , Sefkow A. B. , Sinars D. B. , Rovang D. C. , Peterson K. J. , Cuneo M. E.
Published: March 2010

The radial convergence required to reach fusion conditions is considerably higher for cylindrical than for spherical implosions since the volume is proportional to r2 versus r3, respectively. Fuel magnetization and preheat significantly lowers the required radial convergence enabling cylindrical implosions to become an attractive path toward generating fusion conditions. Numerical simulations are presented indicating that significant fusion yields may be obtained by pulsed-power-driven implosions of cylindrical metal liners onto magnetized (>10 T) and preheated (100–500 eV) deuterium-tritium (DT) fuel. Yields exceeding 100 kJ could be possible on Z at 25 MA, while yields exceeding 50 MJ could be possible with a more advanced pulsed power machine delivering 60 MA. These implosions occur on a much shorter time scale than previously proposed implosions, about 100 ns as compared to about 10 μs for magnetic target fusion (MTF) [I. R. Lindemuth and R. C. Kirkpatrick, Nucl. Fusion 23, 263 (1983)]. Consequently the optimal initial fuel density (1–5 mg/cc) is considerably higher than for MTF (∼1 μg/cc). Thus the final fuel density is high enough to axially trap most of the α-particles for cylinders of approximately 1 cm in length with a purely axial magnetic field, i.e., no closed field configuration is required for ignition. According to the simulations, an initial axial magnetic field is partially frozen into the highly conducting preheated fuel and is compressed to more than 100 MG. This final field is strong enough to inhibit both electron thermal conduction and the escape of α-particles in the radial direction. Analytical and numerical calculations indicate that the DT can be heated to 200–500 eV with 5–10 kJ of green laser light, which could be provided by the Z-Beamlet laser. The magneto-Rayleigh-Taylor (MRT) instability poses the greatest threat to this approach to fusion. Two-dimensional Lasnex simulations indicate that the liner walls must have a substantial initial thickness (10–20% of the radius) so that they maintain integrity throughout the implosion. The Z and Z-Beamlet experiments are now being planned to test the various components of this concept, e.g., the laser heating of the fuel and the robustness of liner implosions to the MRT instability.
Nonequilibrium electronic structure of interacting single-molecule nanojunctions: Vertex corrections and polarization effects for the electron-vibron coupling
Authors: Dash L. K. , Ness H. , Godby R. W.
Published: March 2010

We consider the interaction between electrons and molecular vibrations in the context of electronic transport in nanoscale devices. We present a method based on nonequilibrium Green’s functions to calculate both equilibrium and nonequilibrium electronic properties of a single-molecule junction in the presence of electron-vibron interactions. We apply our method to a model system consisting of a single electronic level coupled to a single vibration mode in the molecule, which is in contact with two electron reservoirs. Higher-order diagrams beyond the usual self-consistent Born approximation (SCBA) are included in the calculations. In this paper we consider the effects of the double-exchange diagram and the diagram in which the vibron propagator is renormalized by one electron-hole bubble. We study in detail the effects of the first- and second-order diagrams on the spectral functions for a large set of parameters and for different transport regimes (resonant and off-resonant cases), both at equilibrium and in the presence of a finite applied bias. We also study the linear response (linear conductance) of the nanojunction for all the different regimes. We find that it is indeed necessary to go beyond the SCBA in order to obtain correct results for a wide range of parameters.
Estimating the spin diffusion length of semiconducting Indium Tin Oxide using Co/Indium Tin Oxide/Co spin valve junctions
Authors: Hakimi A. M. H. R. , Banerjee N. , Aziz A. , Robinson J. W. A. , Blamire M. G.
Published: March 2010

We have measured the transport behavior of Co/Indium Tin Oxide (ITO)/Co current-perpendicular-to-plane submicron spin-valve devices with ITO spacer thickness up to 20 nm, fabricated directly using a three-dimensional focused-ion beam etching technique. Using a simplified Valet–Fert model, we have determined a spin asymmetry ratio for Co of 0.55 and spin diffusion length of 6±1 nm in semiconducting ITO at room temperature.
Contribution of molecular displacements to linear and nonlinear electric susceptibilities of molecular crystals
Authors: Munn R. W.
Published: March 2010

Expressions are derived for additional contributions to the linear, quadratic, and cubic electric susceptibilities of molecular crystals that arise when molecules are displaced by the applied electric field. The contributions depend on quantities related to the infrared intensity of lattice vibrations, to the Raman intensity of lattice vibrations, and to the intensity of hyper-Rayleigh scattering. Some nonlinear contributions are zero except for response to a static electric field applied directly or produced by optical rectification. There are also contributions from averaging the susceptibilities in the equilibrium structure over the lattice modes.
Spectra of the triply charged ion CS23+ and selectivity in molecular Auger effects
Authors: Eland J. H. D. , Rigby C. F. , Andersson E. , Palaudoux J. , Andric L. , Penent F. , Linusson P. , Hedin L. , Karlsson L. , Rubensson J.-E. , Hikosaka Y. , Ito K. , Lablanquie P. , Feifel R.
Published: March 2010

Spectra of triply charged carbon disulphide have been obtained by measuring, in coincidence, all three electrons ejected in its formation by photoionization. Measurements of the CS23+ ion in coincidence with the three electrons identify the energy range where stable trications are formed. A sharp peak in this energy range is identified as the Π2 ground state at 53.1±0.1 eV, which is the lowest electronic state according to ab initio molecular orbital calculations. Triple ionization by the double Auger effect is provisionally divided, on the basis of the pattern of energy sharing between the two Auger electrons into contributions from direct and cascade Auger processes. The spectra from the direct double Auger effect via S 2p, S 2s, and C 1s hole states contain several resolved features and show selectivity based on the initial charge localization and on the identity of the initial state. Triple ionization spectra from single Auger decay of S 2p-based core-valence states CS22+ show retention of the valence holes in this Auger process. Related ion-electron coincidence measurements give the triple ionization yields and the breakdown patterns in triple photoionization at selected photon energies from 90 eV to above the inner shell edges.
The fluid to solid phase transition of hard hyperspheres in four and five dimensions
Authors: Lue L. , Bishop Marvin , Whitlock Paula A.
Published: March 2010

Molecular dynamics and Monte Carlo simulations are performed for four- and five-dimensional hard hyperspheres at a variety of densities, ranging from the fluid state to the solid regime of A4, D4, D4∗, and D5 lattices. The equation of state, the radial distribution functions, and the average number of hyperspheres in a coordination layer are determined. The equations of state are in excellent agreement with values obtained from both theoretical approaches and other simulations. The results for the average number of hyperspheres in a coordination layer are in agreement with the theoretical predictions for the different lattices. The radial distribution function gives better insight about the fluid to solid transition than the equation of state.
Pulse formation in nonlinear left-handed transmission line media
Authors: Kozyrev Alexander B. , van der Weide Daniel W.
Published: March 2010

We report the experimental observation of rf/microwave pulse formation from second harmonic generation in left-handed nonlinear transmission lines.
Rotary motion driven by a direct current electric field
Authors: Takinoue Masahiro , Atsumi Yu , Yoshikawa Kenichi
Published: March 2010

We report the rotary motion of an aqueous microdroplet in an oil phase under a stationary direct current electric field. A droplet exhibits rotary motion under a suitable geometrical arrangement of positive and negative electrodes. Rotary motion appears above a certain critical electric potential and its frequency increases with an increase in the potential. A simple theoretical model is proposed to describe the occurrence of this rotary motion, together with an argument for the future expansion of this micro rotary motor system.
Fabrication of bulk nanocomposite magnets via severe plastic deformation and warm compaction
Authors: Rong Chuanbing , Zhang Ying , Poudyal Narayan , Xiong Xiangyuan , Kramer M. J. , Liu J. Ping
Published: March 2010

We demonstrate that a SmCo/FeCo based hard/soft nanocomposite material can be fabricated by distributing the soft magnetic α-Fe phase particles homogeneously in a hard magnetic SmCo phase through severe plastic deformation. The soft-phase particle size can be reduced from micrometers to smaller than 15 nm upon deformation. Up to 30% of the soft phase can be incorporated into the composites without coarsening. A warm compaction process of the plastically deformed powder particles then produces bulk nanocomposite magnets of fully dense nanocomposites with energy product up to 19.2 MGOe owing to effective interphase exchange coupling, which makes this type of nanocomposite magnets suitable for high energy-density applications at high temperatures.
Chiral angle dependence of resonance window widths in (2n+m) families of single-walled carbon nanotubes
Authors: Hsieh Ya-Ping , Hofmann Mario , Farhat Hootan , Barros Eduardo B. , Kalbac Martin , Kong Jing , Liang Chi-Te , Chen Yang-Fang , Dresselhaus Mildred S.
Published: March 2010

Raman spectra of isolated single-walled carbon nanotubes (SWNTs) were obtained for a wide range of laser excitation energies to study the resonance excitation window of the radial breathing mode feature for members of (2n+m) families. A chiral angle (θ) dependence of the resonance window width (Γ) was observed, which is much stronger than the diameter dependence. The implications of this work on nanotube metrology are discussed.
Amplified spontaneous emission in the cyano-substituted oligo(p-phenylenevinylene) organic crystals: Effect of excitation wavelength
Authors: Fang Hong-Hua , Chen Qi-Dai , Yang Jie , Wang Lei , Jiang Ying , Xia Hong , Feng Jing , Ma Yu-Guang , Wang Hai-Yu , Sun Hong-Bo
Published: March 2010

We report an unusual phenomenon in amplified spontaneous emission (ASE) from cyano-substituted oligo(p-pheny lenevinylene) (CNDPASDB) single crystals, i.e., the ASE peak wavelength, exhibits varied dependence on the pumping wavelength λex. The former is basically kept a constant when λex<505 nm, while a rapid redshift from 560 to 572 nm occurs when λex>505 nm. The observation is different from stimulated Raman resonant scattering (SRRS) in two following aspects: the nonconstant Stokes shift and a much broader emission linewidth. A model describing competition between the stimulated emission and vibration relaxations has been proposed to interpret the underlying mechanism.
Pressure effects on multiferroic LuFe2O4
Authors: Shen X. , Xu C. H. , Li C. H. , Zhang Y. , Zhao Q. , Yang H. X. , Sun Y. , Li J. Q. , Jin C. Q. , Yu R. C.
Published: March 2010

This letter reports that both ac susceptibility and electronic transport measurements of the multiferroic compound LuFe2O4 under pressure show that the transition temperature from the paramagnetic state to the ferrimagnetic state decreases with increasing pressure, indicating that the pressure favors the paramagnetic state and suppresses the ferrimagnetic state. Moreover, the minimum of resistivity changes under pressure, which decreases with increasing pressure, appears at the magnetic phase transition temperature.
Analysis of trap state densities at HfO2/In0.53Ga0.47As interfaces
Authors: Hwang Yoontae , Engel-Herbert Roman , Rudawski Nicholas G. , Stemmer Susanne
Published: March 2010

HfO 2 was deposited on n- and p-type In0.53Ga0.47As by chemical beam deposition. Interface trap densities (Dit) and their energy level distribution were quantified using the conductance method in a wide temperature range (77 to 300 K). A trap level close to the intrinsic energy level caused the Dit to rise above 1013 cm−2 eV−1. The trap level at midgap gives rise to false inversion behavior in the capacitance-voltage curves for n-type channels at room temperature. The apparent decrease of the Dit close to the band edges is discussed.
Band-broadening suppressed effect in long turned geometry channel and high-sensitive analysis of DNA sample by using floating electrokinetic supercharging on a microchip
Authors: Xu Zhongqi , Murata Kenji , Arai Akihiro , Hirokawa Takeshi
Published: March 2010

A featured microchip owning three big reservoirs and long turned geometry channel was designed to improve the detection limit of DNA fragments by using floating electrokinetic supercharging (FEKS) method. The novel design matches the FEKS preconcentration needs of a large sample volume introduction with electrokinetic injection (EKI), as well as long duration of isotachophoresis (ITP) process to enrich low concentration sample. In the curved channel [∼45.6 mm long between port 1 (P1) and the intersection point of two channels], EKI and ITP were performed while the side port 3 (P3) was electrically floated. The turn-induced band broadening with or without ITP process was investigated by a computer simulation (using CFD-ACE+ software) when the analytes traveling through the U-shaped geometry. It was found that the channel curvature determined the extent of band broadening, however, which could be effectively eliminated by the way of ITP. After the ITP-stacked zones passed the intersection point from P1, they were rapidly destacked for separation and detection from ITP to zone electrophoresis by using leading ions from P3. The FEKS carried on the novel chip successfully contributed to higher sensitivities of DNA fragments in comparison with our previous results realized on either a single channel or a cross microchip. The analysis of low concentration 50 bp DNA step ladders (0.23 μg/ml after 1500-fold diluted) was achieved with normal UV detection at 260 nm. The obtained limit of detections (LODs) were on average 100 times better than using conventional pinched injection, down to several ng/ml for individual DNA fragment.
Characterization of Indigestible Carbohydrates in Various Fractions from Wheat Processing
Authors: Haskå L. , Nyman M. , Andersson R.
Published: March 2010

Fractions rich in indigestible carbohydrates, such as fructan and arabinoxylan, are obtained as by‐products when ethanol, starch, and gluten are produced from wheat flour. Today, these fractions are used as animal feed. However, these components may have positive physiological effects in humans. In this study, the content of indigestible carbohydrates in distillers' grains and process streams from the wet fractionation of wheat flour was determined. The fractions were further characterized by ethanol extractability analysis, anion‐exchange chromatography, NMR, and size‐exclusion chromatography. One fraction from wet fractionation contained (g/100 g, db) 6.0 ± 1.0 fructan and 10.3 ± 1.1 dietary fiber (66 ± 4% arabinoxylan), while distillers' grains contained 20.7 g/100 g (db) dietary fiber (30% arabinoxylan). In addition to indigestible carbohydrates from wheat, distillers' grains contained β‐(1→3) and β‐(1→6) glucans and mannoproteins from the yeast and low molecular weight carbohydrates mainly composed of arabinose. The use of endoxylanase in wet fractionation decreased the molecular weight of the arabinoxylans and increased the arabinose to xylose ratio but had no effect on the fructans. In conclusion, waste streams from industrial wheat processing were enriched in fructan, arabinoxylan, and other indigestible carbohydrates. However, the physiological effects of these fractions require further investigation.
Morphologies and Thermal Properties of Hydroxypropylated High‐Amylose Corn Starch
Authors: Liu Hongsheng , Li Ming , Chen Pei , Yu Long , Chen Ling , Tong Zhen
Published: March 2010

High‐amylose (80%) corn starch was modified by hydroxypropylation with different molar substitution (MS). The unique microstructure of high‐amylose starch keeps its granules intact after hydroxypropylation. However, the microstructures and thermal properties strongly depend on the MS of hydroxypropylation. With increasing MS, the granule size was increased, which is partly due to disrupted granule structure, particularly in the amorphous region. Unlike normal starch, the modified high‐amylose corn starch showed a narrow gelatinization range measured by differential scanning calorimetry (DSC), which can be explained by destruction of amylose‐lipid complex. Internal microstructures and morphologies of hydroxypropylated starch were investigated using confocal laser scanning microscopy and to further explore the mechanism of chemical reaction and phase transitions.
Promoting Cereal Grain and Whole Grain Consumption: An Australian Perspective
Authors: Griffiths Trish
Published: March 2010

Go Grains Health & Nutrition encourages consumption of grain‐based foods in Australia through activities that promote awareness and understanding of the role of grain foods in a healthy diet. Strategies drive the message of the Australian dietary guidelines that a healthy diet should include at least four servings of grain‐based foods every day (1 serving is equal to two slices of bread). The “Go Grains 4+ Serves a Day” program promotes grain‐based foods (refined and whole grain) through the media, website information, resource development, school education, and food industry involvement. Interest in whole grains is growing, reflected in a shift in bread sales over recent years from white to whole grain. Manufacturers are responding with new and reformulated whole grain product launches and an increasing number of products carry packaging statements about whole grain content. Australian food regulations do not permit health claims in packaging or in advertising. In the absence of official guidelines, Go Grains has developed a whole grain daily target intake for use by food manufacturers in packaging. There are limited data publicly available to describe consumption of grain‐based foods in Australia. The findings of a 2009 survey commissioned by Go Grains help provide insight into consumption trends.
Regulatory Aspects for Whole Grain and Whole Grain Food: An EU Perspective
Authors: Binns Nino M.
Published: March 2010

Whole grain and whole grain foods enjoy recommendation as part of many national and international dietary guidelines. However, if the food industry makes claims for the health benefits of whole grain foods, then a raft of regulatory requirements must be met in the European Union (EU). Under the relatively recent EU Regulation on nutrition and health claims made on foods, any nutrition claims about the energy, nutrients, fiber, or other beneficial substances the food contains need to comply with the Annex of that Regulation. As far as health claims are concerned, until the Community list of approved so‐called Article 13 claims is published, food businesses may use any health claims that can be validated by scientific evidence, providing that they meet any specific requirements of the Regulation that are applicable prior to that date and providing they are not 1) prohibited claims or 2) claims referring to a reduction in the risk of disease or a disease risk factor or 3) referring to children's development and health or 4) claims that have been rejected by the EU regulatory procedure. Claims under 2) or 3) require submission of a dossier. Once the Community list of health Article 13 claims is published, then only those claims included in the list or those claims approved following submission of a dossier to the European Food Safety Authority may be used. Whole grain foods making nutrition and health claims will also ultimately have to respect the nutrient profiles that will be established under Article 4 of the Regulation. Various definitions of what counts as a whole grain food have been proposed but none has regulatory standing in EU. The conditions of use that will be documented as part of the EU‐approved list of health claims may in essence establish a definition.
Functional interaction between telomere protein TPP1 and telomerase
Authors: Zaug Arthur J. , Podell Elaine R. , Nandakumar Jayakrishnan , Cech Thomas R.
Published: March 2010

Human chromosome end-capping and telomerase regulation require POT1 (Protection of Telomeres 1) and TPP1 proteins, which bind to the 3′ ssDNA extension of human telomeres. POT1–TPP1 binding to telomeric DNA activates telomerase repeat addition processivity. We now provide evidence that this POT1–TPP1 activation requires specific interactions with telomerase, rather than it being a DNA substrate-specific effect. First, telomerase from the fish medaka, which extends the same telomeric DNA primer as human telomerase, was not activated by human POT1–TPP1. Second, mutation of a conserved glycine, Gly100 in the TEN (telomerase essential N-terminal) domain of TERT, abolished the enhancement of telomerase processivity by POT1–TPP1, in contrast to other single amino acid mutations. Chimeric human–fish telomerases that contained the human TEN domain were active but not stimulated by POT1–TPP1, showing that additional determinants of processivity lie outside the TEN domain. Finally, primers bound to mouse POT1A and human TPP1 were activated for extension by human telomerase, whereas mPOT1A–mTPP1 was most active with mouse telomerase, indicating that these mammalian telomerases have specificity for their respective TPP1 proteins. We suggest that a sequence-specific interaction between TPP1 in the TPP1–POT1–telomeric DNA complex and the G100 region of the TEN domain of TERT is necessary for high-processivity telomerase action.
Pregnancy restores the regenerative capacity of the aged liver via activation of an mTORC1-controlled hyperplasia/hypertrophy switch
Authors: Gielchinsky Yuval , Laufer Neri , Weitman Efi , Abramovitch Rinat , Granot Zvi , Bergman Yehudit , Pikarsky Eli
Published: March 2010

Regenerative capacity is progressively lost with age. Here we show that pregnancy markedly improved liver regeneration in aged mice concomitantly with inducing a switch from proliferation-based liver regeneration to a regenerative process mediated by cell growth. We found that the key mediator of this switch was the Akt/mTORC1 pathway; its inhibition blocked hypertrophy, while increasing proliferation. Moreover, pharmacological activation of this pathway sufficed to induce the hypertrophy module, mimicking pregnancy. This treatment dramatically improved hepatic regenerative capacity and survival of old mice. Thus, cell growth-mediated mass reconstitution, which is relatively resistant to the detrimental effects of aging, is employed in a physiological situation and holds potential as a therapeutic strategy for ameliorating age-related functional deterioration.
Expression patterns of the creatine metabolism‐related molecules AGAT, GAMT and CT1 in adult zebrafish Danio rerio
Authors: Wang L. , Chen D. , Yang L. , Huang S. , Zhang Y. , Zhang H.
Published: March 2010

AGAT, GAMT and CT1, three creatine synthesis and transport‐related molecules, have been widely studied in mammals. To explore their homologous genes in adult zebrafish Danio rerio, the gene expression patterns of these three genes in D. rerio were investigated. The results reveal that AGAT, GAMT and CT1 are expressed widely in diverse tissues of D. rerio where the homologous genes in mammals are also expressed.
Population differentiation in perch Perca fluviatilis: environmental effects on gene flow?
Authors: Bergek S. , Sundblad G. , Björklund M.
Published: March 2010

Environmental parameters were used to investigate barriers to gene flow and genetic differentiation in the Eurasian perch (Perca fluviatilis L.) at a small geographical scale in an archipelago system. Significant genetic differentiation was found among locations. Distance per se did not play a major role in the reduction of gene flow. Instead, the largest genetic differences between populations correlated with major changes in environmental conditions, such as temperature at time of spawning. The results show that genetic divergence can arise between populations in habitats thought to be highly connected, and that environmental variables can influence the level of gene flow between populations, including those that are at small spatial scales (tens of kilometres). The importance of a landscape approach when investigating genetic differentiation and defining barriers to gene flow is highlighted.
Bcl11b heterozygosity promotes clonal expansion and differentiation arrest of thymocytes in γ‐irradiated mice
Authors: Go Rieka , Hirose Satoshi , Morita Shinichi , Yamamoto Takashi , Katsuragi Yoshinori , Mishima Yukio , Kominami Ryo
Published: March 2010

Bcl11b encodes a zinc‐finger transcription factor and functions as a haploinsufficient tumor suppressor gene. Bcl11bKO/KO mice exhibit differentiation arrest of thymocytes during β‐selection as has been observed with other mouse models involving knockouts of genes in the Wnt/β‐catenin signaling pathway. Recurrent chromosomal rearrangement at the BCL11B locus occurs in human T‐cell leukemias, but it is not clear how such rearrangement would contribute to lymphomagenesis. To address this issue, we studied clonal cell growth, cell number, and differentiation of thymocytes in Bcl11bKO/+ mice at different time points following γ‐irradiation. Analysis of D‐J rearrangement at the T cell receptor β‐chain (TCRβ) locus and cell surface markers by flow cytometry revealed two distinct populations of clonally growing thymocytes. In one population, thymocytes share a common D‐J rearrangement but retain the capacity to differentiate. In contrast, thymocytes in the second population have lost their ability to differentiate. Since the capacity to self renew and differentiate into multiple cell lineages are fundamental properties of adult stem cells, the differentiation competent population of thymocytes that we have isolated could potentially function as cancer stem cells. We also demonstrate increased expression of β‐catenin, a well‐known oncogenic protein, in Bcl11bKO/+ thymocytes. Collectively, the Bcl11bKO/+ genotype contributes to clonal expansion and differentiation arrest in part through an increase in the level of β‐catenin. (Cancer Sci 2010)