bluuebunny/crossref_metadata_2025 huggingface dataset:
Consumption of soda and other sugar-sweetened beverages by 2-year-olds: findings from a population-based survey
Authors: Garnett Bernice Raveche , Rosenberg Kenneth D , Morris Daniel S
Published: October 2012

Objective

To determine risk factors for consumption of soda and other sugar-sweetened beverages (SSB) among 2-year-old children.

Design

The analysis was performed using three linked data sets: the 2004–2005 Oregon Pregnancy Risk Assessment Monitoring Survey (PRAMS); its longitudinal follow-up, 2006–2007 Oregon PRAMS-2; and 2004–2005 Oregon birth certificates.

Setting

PRAMS is a surveillance programme supported by the federal Centers for Disease Control and Prevention and implemented by participating state health departments. Using mixed methods, PRAMS surveys women 2–6 months after a live birth. Oregon PRAMS-2 re-interviews respondents shortly after the index child's second birthday. Oregon PRAMS oversamples minority women.

Subjects

Using monthly cohorts, we randomly selected 5851 women from the 2004–2005 birth certificates. In total 1911 women completed both PRAMS and PRAMS-2. The weighted response rate of PRAMS-2 was 43·5 %.

Results

Almost half of mothers (49·9 %) reported that their child drank SSB on at least 1 d/week. Mothers whose children drank SSB at least once weekly were more likely to have low income (adjusted OR = 2·83, 95 % CI 2·09, 3·83) and to eat out on ≥2 d/week (OR = 2·11 %, 95 % CI 1·66, 2·70). Hispanic and non-Hispanic black women were most likely to report that their child drank SSB at least once weekly.

Conclusions

Half of mothers reported that their 2-year-old children drank SSB at least once weekly. Public health interventions and policies should address childhood SSB consumption including educating health-care providers and parents.
Validation of a home food inventory among low-income Spanish- and Somali-speaking families
Authors: Hearst Mary O , Fulkerson Jayne A , Parke Michelle , Martin Lauren
Published: October 2012

Objective

To refine and validate an existing home food inventory (HFI) for low-income Somali- and Spanish-speaking families.

Design

Formative assessment was conducted using two focus groups, followed by revisions of the HFI, translation of written materials and instrument validation in participants’ homes.

Setting

Twin Cities Metropolitan Area, Minnesota, USA.

Subjects

Thirty low-income families with children of pre-school age (fifteen Spanish-speaking; fifteen Somali-speaking) completed the HFI simultaneously with, but independently of, a trained staff member. Analysis consisted of calculation of both item-specific and average food group kappa coefficients, specificity, sensitivity and Spearman's correlation between participants’ and staff scores as a means of assessing criterion validity of individual items, food categories and the obesogenic score.

Results

The formative assessment revealed the need for few changes/additions for food items typically found in Spanish-speaking households. Somali-speaking participants requested few additions, but many deletions, including frozen processed food items, non-perishable produce and many sweets as they were not typical food items kept in the home. Generally, all validity indices were within an acceptable range, with the exception of values associated with items such as ‘whole wheat bread’ (κ= 0·16). The obesogenic score (presence of high-fat, high-energy foods) had high criterion validity withκ= 0·57, sensitivity = 91·8 %, specificity = 70·6 % and Spearman correlation = 0·78.

Conclusions

The revised HFI is a valid assessment tool for use among Spanish and Somali households. This instrument refinement and validation process can be replicated with other population groups.
The ‘too few, too bright’ tropical low‐cloud problem in CMIP5 models
Authors: Nam C. , Bony S. , Dufresne J.‐L. , Chepfer H.
Published: October 2012

Previous generations of climate models have been shown to under‐estimate the occurrence of tropical low‐level clouds and to over‐estimate their radiative effects. This study analyzes outputs from multiple climate models participating in the Fifth phase of the Coupled Model Intercomparison Project (CMIP5) using the Cloud Feedback Model Intercomparison Project Observations Simulator Package (COSP), and compares them with different satellite data sets. Those include CALIPSO lidar observations, PARASOL mono‐directional reflectances and CERES radiative fluxes at the top of the atmosphere. We show that current state‐of‐the‐art climate models predict overly bright low‐clouds, even for a correct low‐cloud cover. The impact of these biases on the Earth' radiation budget, however, is reduced by compensating errors. Those include the tendency of models to under‐estimate the low‐cloud cover and to over‐estimate the occurrence of mid‐ and high‐clouds above low‐clouds. Finally, we show that models poorly represent the dependence of the vertical structure of low‐clouds on large‐scale environmental conditions. The implications of this ‘too few, too bright low‐cloud problem’ for climate sensitivity and model development are discussed.
Fragmented Indian plate and vertically coherent deformation beneath eastern Tibet
Authors: Ceylan Savas , Ni James , Chen John Y. , Zhang Qie , Tilmann Frederik , Sandvol Eric
Published: October 2012

Using fundamental mode Rayleigh waves from the INDEPTH‐IV and Namche‐Barwa seismic experiments for periods between 20 and 143 s, we have investigated the lithospheric structure beneath eastern Tibet. We have found a ∼200‐km‐wide high velocity body, starting at ∼60 km depth and roughly centered beneath the Bangong‐Nijuang Suture, which is most likely a piece of the underthrusting Indian continental lithosphere. The sub‐horizontal underthrusting of the Indian lithosphere beneath eastern Tibet appears to be accompanied by its lateral tearing into at least two fragments, and subsequent break‐off of the westernmost portion at ∼91°E‐33°N. The uppermost mantle low velocity zone we observe beneath the N. Qiangtang and Songpan‐Ganzi terranes is most probably due to warmer and thinner lithosphere relative to southern Tibet. We attribute the low velocity zones concentrated along the northern and southern branches of the eastern Kunlun fault at lithospheric depths to strain heating caused by shearing. The azimuthal fast directions at all periods up to 143 s (∼200 km peak sensitivity depth) beneath the N. Qiangtang and Songpan‐Ganzi terranes are consistent, suggesting vertically coherent deformation between crust and uppermost mantle. Furthermore, the low velocity zone below the Kunlun Shan reaching down to >200 km argues against a present southward continental subduction along the southern margin of Qaidam Basin.
Tracking Kelvin waves from the equatorial troposphere into the stratosphere
Authors: Flannaghan T. J. , Fueglistaler S.
Published: October 2012

Convectively coupled Kelvin waves in the troposphere have a vertically propagating component which propagates through the tropical tropopause layer into the stratosphere. In the tropical tropopause layer above the typical top of deep convection, these waves propagate as dry waves. In the stratosphere they contribute to the forcing of the stratospheric quasi‐biennial oscillation. Here, we address the challenge to track individual waves in a region where both static stability and background wind rapidly change with a new algorithm that operates in real space and uses the full longitude/height/time information available to reliably identify Kelvin waves. We argue that our algorithm overcomes inherent ambiguities in previously published methods. Specifically, our algorithm cleanly separates wave activity and number of waves, and successfully tracks waves also in regions where background wind reduces wave amplitudes. Applied to ECMWF reanalysis data for the period 1989–2011, we obtain a statistical description of Kelvin wave propagation that shows propagation through the TTL into the stratosphere occurs predominantly over the Indian Ocean and Atlantic.
Laboratory emissivity measurements of the plagioclase solid solution series under varying environmental conditions
Authors: Donaldson Hanna K. L. , Thomas I. R. , Bowles N. E. , Greenhagen B. T. , Pieters C. M. , Mustard J. F. , Jackson C. R. M. , Wyatt M. B.
Published: October 2012

New laboratory thermal infrared emissivity measurements of the plagioclase solid solution series over the 1700 ∼ 400 cm−1 (6–25 μm) spectral range are presented. Thermal infrared (TIR) spectral changes for fine‐particulate samples (0–25 μm) are characterized for the first time under different laboratory environmental conditions: ambient (terrestrial‐like), half‐vacuum (Mars‐like), vacuum, and vacuum with cooled chamber (lunar‐like). Under all environmental conditions the Christiansen Feature (CF) is observed to vary in a systematic way with Na‐rich end‐member (albite) having a CF position at the highest wave number (shortest wavelength) and the Ca‐rich end‐member (anorthite) having a CF position with the lowest wave number (longest wavelength). As pressure decreases to <10−3 mbar four observations are made: (1) the CF position shifts to higher wave numbers, (2) the spectral contrast of the CF increases relative to the RB, (3) the spectral contrast of the RB in the ∼1200–900 spectral range decreases while the spectral contrast of the RB in the ∼800–400 spectral range either increases or remains the same and (4) the TF disappears. A relationship between the wavelength position of the CF measured under simulated lunar conditions and plagioclase composition (An#) is developed. Although its exact form may evolve with additional data, this linear relationship should be applied to current and future TIR data sets of the Moon. Our new spectral measurements demonstrate how sensitive thermal infrared emissivity spectra of plagioclase feldspars are to the environmental conditions under which they are measured and provide important constraints for interpreting current and future thermal infrared data sets.
Gut microbiome composition is linked to whole grain-induced immunological improvements
Authors: Martínez Inés , Lattimer James M , Hubach Kelcie L , Case Jennifer A , Yang Junyi , Weber Casey G , Louk Julie A , Rose Devin J , Kyureghian Gayaneh , Peterson Daniel A , Haub Mark D , Walter Jens
Published: October 2012

The involvement of the gut microbiota in metabolic disorders, and the ability of whole grains to affect both host metabolism and gut microbial ecology, suggest that some benefits of whole grains are mediated through their effects on the gut microbiome. Nutritional studies that assess the effect of whole grains on both the gut microbiome and human physiology are needed. We conducted a randomized cross-over trial with four-week treatments in which 28 healthy humans consumed a daily dose of 60 g of whole-grain barley (WGB), brown rice (BR), or an equal mixture of the two (BR+WGB), and characterized their impact on fecal microbial ecology and blood markers of inflammation, glucose and lipid metabolism. All treatments increased microbial diversity, the Firmicutes/Bacteroidetes ratio, and the abundance of the genus Blautia in fecal samples. The inclusion of WGB enriched the genera Roseburia, Bifidobacterium and Dialister, and the species Eubacterium rectale, Roseburia faecis and Roseburia intestinalis. Whole grains, and especially the BR+WGB treatment, reduced plasma interleukin-6 (IL-6) and peak postprandial glucose. Shifts in the abundance of Eubacterium rectale were associated with changes in the glucose and insulin postprandial response. Interestingly, subjects with greater improvements in IL-6 levels harbored significantly higher proportions of Dialister and lower abundance of Coriobacteriaceae. In conclusion, this study revealed that a short-term intake of whole grains induced compositional alterations of the gut microbiota that coincided with improvements in host physiological measures related to metabolic dysfunctions in humans.
Characterization and transcription of arsenic respiration and resistance genes during in situ uranium bioremediation
Authors: Giloteaux Ludovic , Holmes Dawn E , Williams Kenneth H , Wrighton Kelly C , Wilkins Michael J , Montgomery Alison P , Smith Jessica A , Orellana Roberto , Thompson Courtney A , Roper Thomas J , Long Philip E , Lovley Derek R
Published: October 2012

The possibility of arsenic release and the potential role of Geobacter in arsenic biogeochemistry during in situ uranium bioremediation was investigated because increased availability of organic matter has been associated with substantial releases of arsenic in other subsurface environments. In a field experiment conducted at the Rifle, CO study site, groundwater arsenic concentrations increased when acetate was added. The number of transcripts from arrA, which codes for the α-subunit of dissimilatory As(V) reductase, and acr3, which codes for the arsenic pump protein Acr3, were determined with quantitative reverse transcription-PCR. Most of the arrA (>60%) and acr3-1 (>90%) sequences that were recovered were most similar to Geobacter species, while the majority of acr3-2 (>50%) sequences were most closely related to Rhodoferax ferrireducens. Analysis of transcript abundance demonstrated that transcription of acr3-1 by the subsurface Geobacter community was correlated with arsenic concentrations in the groundwater. In contrast, Geobacter arrA transcript numbers lagged behind the major arsenic release and remained high even after arsenic concentrations declined. This suggested that factors other than As(V) availability regulated the transcription of arrA in situ, even though the presence of As(V) increased the transcription of arrA in cultures of Geobacter lovleyi, which was capable of As(V) reduction. These results demonstrate that subsurface Geobacter species can tightly regulate their physiological response to changes in groundwater arsenic concentrations. The transcriptomic approach developed here should be useful for the study of a diversity of other environments in which Geobacter species are considered to have an important influence on arsenic biogeochemistry.
‘Sponge-specific’ bacteria are widespread (but rare) in diverse marine environments
Authors: Taylor Michael W , Tsai Peter , Simister Rachel L , Deines Peter , Botte Emmanuelle , Ericson Gavin , Schmitt Susanne , Webster Nicole S
Published: October 2012

Numerous studies have reported the existence of sponge-specific 16S ribosomal RNA (rRNA) gene sequence clusters, representing bacteria found in sponges but not detected in other environments, such as seawater. The advent of deep-sequencing technologies allows us to examine the rare microbial biosphere in order to establish whether these bacteria are truly sponge specific, or are more widely distributed but only at abundances below the detection limit of conventional molecular approaches. We screened >12 million publicly available 16S rRNA gene pyrotags derived from 649 seawater, sediment, hydrothermal vent and coral samples from temperate, tropical and polar regions. We detected 77 of the 173 previously described sponge-specific clusters in seawater or other non-sponge samples, albeit generally at extremely low abundances. Sequences representing the candidate phylum ‘Poribacteria’, previously thought to be largely restricted to sponges, were recovered from 46 (out of 411) seawater and 41 (out of 129) sediment samples. While the presence of an organism does not imply that it is active in situ, our results do suggest that many ‘sponge-specific’ bacteria occur more widely outside of sponge hosts than previously thought.
Tsallis entropies and matrix trace inequalities in quantum statistical mechanics
Authors: Bebiano N. , da Providência J. , da Providência J. P.
Published: October 2012

Extensions of trace inequalities arising in statistical mechanics are derived in a straightforward and unified way from a variational characterization of the Tsallis entropy. Namely, one-parameter extension of the thermodynamic inequality is presented and its equivalence to a generalized Peierls–Bogoliubov inequality is stated, in the sense that one may be obtained from the other, and vice versa.
Determination of salinity gradient power potential in Québec, Canada
Authors: Berrouche Y. , Pillay P.
Published: October 2012

Electrical energy can be produced from the chemical potential difference of two liquids with dissimilar salinities. This source of energy is known as salinity gradient power. In this paper, the theory, the technologies used to exploit the power, the major challenges, and their development trends are first presented. Then a modeling of fluxes across semi permeable membranes is proposed and validated. Next, an energy balance study is done in order to estimate the power potential for a given salinity gradient system. By applying this study to several rivers in Quebec, the salinity power gradient potential is estimated to 45 TWh/yr based on the minimal flow rate of each river.
Spin relaxation of negatively charged excitons in (In,Al)As/AlAs quantum dots with indirect band gap and type-I band alignment
Authors: Dunker D. , Shamirzaev T. S. , Debus J. , Yakovlev D. R. , Zhuravlev K. S. , Bayer M.
Published: October 2012

Spin dynamics of negatively charged excitons is experimentally studied in (In,Al)As/AlAs quantum dots with indirect band gap and type-I band alignment. At low temperatures of 1.8 K, the spin relaxation time is 55 μs in a magnetic field of 3 T. It decreases with increasing magnetic field as B−5, which evidences that the spin relaxation of the negatively charged excitons is provided by an one-acoustic-phonon process.
On the quantum theory of molecules
Authors: Sutcliffe Brian T. , Woolley R. Guy
Published: October 2012

Transition state theory was introduced in 1930s to account for chemical reactions. Central to this theory is the idea of a potential energy surface (PES). It was assumed that such a surface could be constructed using eigensolutions of the Schrödinger equation for the molecular (Coulomb) Hamiltonian but at that time such calculations were not possible. Nowadays quantum mechanical ab initio electronic structure calculations are routine and from their results PESs can be constructed which are believed to approximate those assumed derivable from the eigensolutions. It is argued here that this belief is unfounded. It is suggested that the potential energy surface construction is more appropriately regarded as a legitimate and effective modification of quantum mechanics for chemical purposes.
Pure and entangled ${\cal N}=4$N=4 linear supermultiplets and their one-dimensional sigma-models
Authors: Gonzales Marcelo , Iga Kevin , Khodaee Sadi , Toppan Francesco
Published: October 2012

“Pure” homogeneous linear supermultiplets (minimal and non-minimal) of the ${\cal N}=4$N=4-extended one-dimensional supersymmetry algebra are classified. “Pure” means that they admit at least one graphical presentation (the corresponding graph/graphs are known as “Adinkras”). We further prove the existence of “entangled” linear supermultiplets which do not admit a graphical presentation, by constructing an explicit example of an entangled ${\cal N}=4$N=4 supermultiplet with field content (3, 8, 5). It interpolates between two inequivalent pure ${\cal N}=4$N=4 supermultiplets with the same field content. The one-dimensional ${\cal N}=4$N=4 sigma-model with a three-dimensional target based on the entangled supermultiplet is presented. The distinction between the notion of equivalence for pure supermultiplets and the notion of equivalence for their associated graphs (Adinkras) is discussed. Discrete properties such as “chirality” and “coloring” can discriminate different supermultiplets. The tools used in our classification include, among others, the notion of field content, connectivity symbol, commuting group, node choice group, and so on.
Self-consistently modeling the electronic behavior of “active” nanostructures: Scaling of ionized donor density at the nanoscale
Authors: Williams Owen L. , Rees Paul , Wilks Steve P.
Published: October 2012

We present a powerful and versatile method for calculating the electronic properties of real nanostructures. It is applied to a spherical quantum dot, self-consistently reconciling the non-linear Poisson equation with the Kohn-Sham equations, balancing the charge in the surface states and the “bulk” (dot interior). Excellent agreement is obtained between theory and experiment, with the model predicting a spatial dependency of donor ionization for dots below 10 nm radii. This has far reaching implications for nano-device design.
Maintain rigid structures in Verlet based Cartesian molecular dynamics simulations
Authors: Tao Peng , Wu Xiongwu , Brooks Bernard R.
Published: October 2012

An algorithm is presented to maintain rigid structures in Verlet based Cartesian molecular dynamics (MD) simulations. After each unconstrained MD step, the coordinates of selected particles are corrected to maintain rigid structures through an iterative procedure of rotation matrix computation. This algorithm, named as SHAPE and implemented in CHARMM program suite, avoids the calculations of Lagrange multipliers, so that the complexity of computation does not increase with the number of particles in a rigid structure. The implementation of this algorithm does not require significant modification of propagation integrator, and can be plugged into any Cartesian based MD integration scheme. A unique feature of the SHAPE method is that it is interchangeable with SHAKE for any object that can be constrained as a rigid structure using multiple SHAKE constraints. Unlike SHAKE, the SHAPE method can be applied to large linear (with three or more centers) and planar (with four or more centers) rigid bodies. Numerical tests with four model systems including two proteins demonstrate that the accuracy and reliability of the SHAPE method are comparable to the SHAKE method, but with much more applicability and efficiency.
Effective light management of three-dimensionally patterned transparent conductive oxide layers
Authors: Kim Joondong , Kim Mingeon , Kim Hyunyub , Song Kyuwan , Lee Eunsongyi , Kim Dong-Wook , Yun Ju-Hyung , Choi Byung-Ik , Lee Sunhwa , Jeong Chaehwan , Yi Junsin
Published: October 2012

For effective light harvesting, a design weighting should be implemented in a front geometry, in which the incident light transmits from a surface into a light-active layer. We designed a three-dimensionally patterned transparent conductor layer for effective light management. A transparent conductive oxide (TCO) film was formed as three-dimensional structures. This efficiently drives the incident light at the front surface into a Si absorber to yield a reduction in reflection and an enhancement of current. This indicates that an optimum architecture for a front TCO surface will provide an effective way for light management in solar cells.
Tunable, narrow-band, all-metallic microwave absorber
Authors: Mattiucci N. , Trimm R. , D'Aguanno G. , Aközbek N. , Bloemer M. J.
Published: October 2012

We exploit the metamaterial properties of a thick metallic grating with extreme sub-wavelength slits on a metallic slab to achieve complete absorption of transverse magnetic polarized microwaves. We measure narrow bands of total absorption (up to 99.9999%) from normal to grazing incidence that can be tuned by varying an air gap between the grating and the slab. Unlike typical absorbers, the structure is mostly metallic with a 97% filling factor, and no absorptive material beside the metal itself is employed. We access the absorption properties of metals in the microwave where they are commonly believed to be perfect reflectors.
Structural-dependent thermal conductivity of aluminium nitride produced by reactive direct current magnetron sputtering
Authors: Belkerk B. E. , Soussou A. , Carette M. , Djouadi M. A. , Scudeller Y.
Published: October 2012

This Letter reports the thermal conductivity of aluminium nitride (AlN) thin-films deposited by reactive DC magnetron sputtering on single-crystal silicon substrates (100) with varying plasma and magnetic conditions achieving different crystalline qualities. The thermal conductivity of the films was measured at room temperature with the transient hot-strip technique for film thicknesses ranging from 100 nm to 4000 nm. The thermal conductivity was found to increase with the thickness depending on the synthesis conditions and film microstructure. The conductivity in the bulk region of the films, so-called intrinsic conductivity, and the boundary resistance were in the range [120–210] W m−1 K−1 and [2-30 × 10−9] K m2 W−1, respectively, in good agreement with microstructures analysed by x-ray diffraction, high-resolution-scanning-electron-microscopy, and transmission-electron-microscopy.
Ellipsometry applied to phase transitions and relaxation phenomena in Ni2MnGa ferromagnetic shape memory alloy
Authors: Dejneka A. , Zablotskii V. , Tyunina M. , Jastrabik L. , Pérez-Landazábal J. I. , Recarte V. , Sánchez-Alarcos V. , Chernenko V. A.
Published: October 2012

The temperature dependences of the refractive index, n(T), calculated from ellipsometric data during the premartensitic and martensite transitions in a Ni2MnGa ferromagnetic shape memory alloy allow to detect all critical temperatures of the sample. The performed measurements reveal the behavior of a surface layer of a few tens nanometers depth due to the light absorption. Optical measurements reveal the earlier onset of premartensitic transition at the sample surface and shows unknown new features like time and temperature dependent effects related to the crystal surface. The underlying mechanisms of the observed temperature changes of the equilibrium n0 may be related to temperature dependent interactions between free electrons and phonons as well as between electrons and defects. A giant isothermal creep (up to 20%) of the refractive index was found for temperatures below T0 = 315 K. Below T0 the creep amplitude grows with the temperature difference T0-T. The creep disappears and the relaxation time becomes zero at temperatures above T0.
Interaction of n-type dopants with oxygen in silicon and germanium
Authors: Chroneos A. , Sgourou E. N. , Londos C. A.
Published: October 2012

Density functional theory calculations are employed to gain a fundamental insight on the interaction of n-type dopants such as phosphorous and arsenic with oxygen interstitials and A-centers (vacancy-oxygen interstitial pairs) in silicon and germanium. We propose the formation of the phosphorous-vacancy-oxygen interstitial and arsenic-vacancy-oxygen interstitial cluster in both silicon and germanium.
Acoustic resonator based on periodically poled transducers: Fabrication and characterization
Authors: Bassignot F. , Courjon E. , Ulliac G. , Ballandras S. , Lesage J.-M. , Petit R.
Published: October 2012

Passive radiofrequency filters and resonators exploited for telecommunication applications are generally based on surface or bulk acoustic wave (SAW or BAW) devices. However, these devices present some technological limits as short-circuits between the electrodes of the interdigital transducers (for SAW devices) or an accurate control of the resonator dimension (plate or film thickness for BAW devices). An alternative concept based on periodically poled transducers (PPT) implemented on ferroelectric substrates (LiNbO3 or LiTaO3) embedded between two guiding substrates yielding advanced packaging opportunities has been developed. An oscillator stabilized by such a PPT-based resonator operating at 131 MHz has been successfully fabricated. A phase noise of −165 dBc/Hz at 60 kHz from the carrier has been measured with an input power of 2 mW and a relative short term frequency stability of 10−9 per second. Other resonators built on waveguides exploiting thinned PPTs (around thirty microns) have allowed the excitation of only one contribution with a thermal sensibility equal to the one of the guiding materials (−30 ppm/K for silicon).
Spin filtering and spin separating effects in U-shaped topological insulator devices
Authors: Zeng Minggang , Liang Gengchiau
Published: October 2012

Using non-equilibrium Green's function (NEGF), we investigate spin transport properties of a U-shaped, multi-terminal device based on two-dimensional topological insulator (2DTI), such as HgTe quantum well (HgTe QW). The results show that this 2DTI multi-terminal device can be implemented as a perfect spin filter operating in the absence of ferromagnetic electrodes and external magnetic field. The electrically tunable spin polarization can approach 100%. Moreover, the device can redistribute electrons with opposite spins from an unpolarized source to different leads, resulting in a bifunctional device, which can simultaneously operate as a spin filter and a spin separator. These interesting transport properties can be attributed to the unique helical edge states in a quantum spin Hall system. The performance of the U-shaped device is robust against the weak disorder and the variation in widths and bias voltages, but deteriorates in the presence of the strong disorder and vacancies. The capability of generating highly polarized and controllable spin currents in 2DTI indicates the application of topologically protected and low-powered spintronics.
The direct and indirect bandgaps of unstrained SixGe1−x−ySny and their photonic device applications
Authors: Moontragoon P. , Soref R. A. , Ikonic Z.
Published: October 2012

Using empirical pseudopotential theory, the direct (Γ) and indirect bandgaps (L and X) of unstrained crystalline SixGe1−x−ySny have been calculated over the entire xy composition range. The results are presented as energy-contour maps on ternary diagrams along with a ternary plot of the predicted lattice parameters. A group of 0.2 to 0.6 eV direct-gap SiGeSn materials is found for a variety of mid-infrared photonic applications. A set of “slightly indirect” SiGeSn alloys having a direct gap at 0.8 eV (but with a smaller L-Γ separation than in Ge) have been identified. These materials will function like Ge in various telecom photonic devices. Hetero-layered SiGeSn structures are described for infrared light emitters, amplifiers, photodetectors, and modulators (free carrier or Franz-Keldysh). We have examined in detail the optimized design space for mid-infrared SiGeSn-based multiple-quantum-well laser diodes, amplifiers, photodetectors, and quantum-confined Stark effect modulators.
Surface plasmon amplification characteristics of an active three-layer nanoshell-based spaser
Authors: Zhang Haopeng , Zhou Jun , Zou Weibo , He Miao
Published: October 2012

Surface plasmon (SP) amplification by stimulated emission of radiation (spaser) of the active nanoshell with three-layer silica-gold-silica structure is proposed. The properties of the spaser are numerically analyzed based on Mie theory. The results show that the nanoshell-based spaser is one order of magnitude higher than the nanosphere-based and nanoegg-based spasers in the surface plasmon amplification, but the gain threshold kthre of the silica is nearly one order of magnitude lower. In addition, the behavior of the nanoshell-based spaser depends on structural parameters that are explained by the quenching effect, plasmon hybridization theory, and dynamic photon-plasmon coupling mechanism. By optimizing the structure parameters of the layered nanoshell, an extremely high spaser enhancement over a wider operating range of wavelength tunings was obtained, both aspects having important significance in practical applications.
Vacuum-enhanced nickel-induced crystallization of hydrogenated amorphous silicon
Authors: Budini N. , Rinaldi P. A. , Arce R. D. , Schmidt J. A. , Koropecki R. R. , Buitrago R. H.
Published: October 2012

We report the results of enhanced nickel induced crystallization of intrinsic hydrogenated amorphous silicon thin films under vacuum conditions. Crystallization was performed by conventional furnace annealing at both atmospheric pressure and vacuum or low pressure conditions (≈10–6 Torr) for comparison. We have investigated the influence of low pressure during annealing on the resulting polycrystalline films by means of optical microscopy, ultraviolet reflectance, and photoacoustic spectrometry measurements. A faster crystallization and a smaller grain size were observed when the process is carried out under vacuum, with an annealing time reduction of more than 50%. We discuss, from a thermodynamical viewpoint, some possible causes by which vacuum annealing influences incubation and nucleation stages due to the presence of mobile hydrogen atoms inside the amorphous silicon matrix. Large grains with diameters of 30 and 100 μm were obtained at vacuum and atmospheric pressure, respectively.
Growth and characterization of LuAs films and nanostructures
Authors: Krivoy E. M. , Nair H. P. , Crook A. M. , Rahimi S. , Maddox S. J. , Salas R. , Ferrer D. A. , Dasika V. D. , Akinwande D. , Bank S. R.
Published: October 2012

We report the growth and characterization of nearly lattice-matched LuAs/GaAs heterostructures. Electrical conductivity, optical transmission, and reflectivity measurements of epitaxial LuAs films indicate that LuAs is semimetallic, with a room-temperature resistivity of 90 μΩ cm. Cross-sectional transmission electron microscopy confirms that LuAs nucleates as self-assembled nanoparticles, which can be overgrown with high-quality GaAs. The growth and material properties are very similar to those of the more established ErAs/GaAs system; however, we observe important differences in the magnitude and wavelength of the peak optical transparency, making LuAs superior for certain device applications, particularly for thick epitaxially embedded Ohmic contacts that are transparent in the near-IR telecommunications window around 1.3 μm.
Real-time diagnosis and fault detection for the monitoring of the wind turbine
Authors: Bennouna O. , Héraud N.
Published: October 2012

The present paper addresses fault signature analysis for fault detection and isolation problems. The aim of this article is to create a procedure for detecting and locating abnormal behaviour in an operating wind turbine before possibly catastrophic failures. Each of the three fault classes (bias, incipient fault, and intermittent fault) is successfully studied. Wind energy systems with a doubly fed induction generator example are illustrated to show the effectiveness of the proposed diagnosis method. An experimental benchmark emulating the behaviour of a wind turbine is used to confirm the approach. Finally, real time tests are performed to allow real time validation.
A leaky-wave groove antenna at optical frequency
Authors: Polemi Alessia , Maci Stefano
Published: October 2012

In the framework of nanoantennas functioning at optical frequencies, we present here a new kind of leaky-wave antenna realized as a groove in an aluminum superstrate, supported by a silver substrate. The antenna works in the optical frequency range where the silver acts as a dielectric with equivalent refractive index between zero and one. Under these conditions, the dominant mode launched in the structure exhibits a phase velocity larger than the speed of light in free-space, thus producing a leaky-wave radiation in free-space. We propose a simplified analytical form of the dispersion characteristic of the fundamental mode supported by the structure, which allows for identification of the radiative leaky-wave condition. We also propose approximate formulas for calculating the antenna gain and loss efficiency. The results obtained through these formulas are successfully compared with full-wave simulations. The final parametric study shows how the radiation characteristic is affected by the variation of geometric features.
High-resolution photoelectron spectroscopy of linear ← bent polyatomic photodetachment transitions: The electron affinity of CS2
Authors: Cavanagh S. J. , Gibson S. T. , Lewis B. R.
Published: October 2012

A combination of high-resolution velocity-map-imaging photoelectron spectroscopy and isotopic substitution is used to show that precise electron affinities can be obtained from polyatomic photodetachment spectra, even for cases involving significant changes in equilibrium geometry between the molecular neutral and anion. The chosen example CS2 \documentclass[12pt]{minimal}\begin{document}$(X\,{^1\Sigma _g^+})$\end{document}(XΣg+1) (linear) ← \documentclass[12pt]{minimal}\begin{document}${\rm CS}_2^-$\end{document} CS 2− (X 2A1) (bent) photodetachment transition is found to preferentially access highly-excited v2 (bending) levels of the neutral, with no observation possible of the lowest-v2 bands. Nevertheless, through 13C isotopic substitution, the v2 numbering is established unambiguously and the adiabatic electron affinity of CS2 is found to be 4456(10) cm−1 [0.5525(13) eV], by far the most precise value reported to date.
Performances on engine-out emissions and combustion of ethylene glycol monobutyl ether palm oil monoester as a newtype biodiesel
Authors: Jiang Dayong A. , Bai Yun B.
Published: October 2012

In order to enhance the effect of traditional biodiesel in reducing engine-out smoke formation, the introduction of other ether group into its molecule was attempted. Now a novel biodiesel named ethylene glycol monobutyl ether palm oil monoester is developed, which owns more environment-friendly than the traditional biodiesel. The fuel was synthesized with palm oil and ethylene glycol monobutyl ether, structurally identified through FT-IR, P1PH NMR and GPC analyses. Engine test results show that when a tested diesel engine is fueled with this biodiesel(B100) and its mixture with diesel fuel(B25) in place of 0# diesel fuel(B0), engine-out smoke emissions for B100 can be significantly decreased by 9%–54.6%, while CO, NOx, and unburned hydrocarbon emissions are also lessened 50.0%–66.7%, 25.7%–37.1%, and 45.5%–58.3%, respectively, compared with B0 under partial load modes. The similar situation was also adequate to B25. In the area of combustion performances, B100 is ignited earlier during diesel engine operation, so utilization of the new biodiesel can remarkably improve engine brake thermal efficiency. Because of certain amount of oxygen contained in the new biodiesel resulting in the low calorific value, the higher cetane number and shorter ignition delay, both engine in-cylinder pressure and its changing rate with crankshaft angle are increased to some extent for ethylene glycol monobutyl ether palm oil monoester, and the combustion of it can lead to a little higher heat release rate than diesel fuel.
Simple Method and Materials to Target Co(II)-Dy(III) Multi-Nuclear Magnetic Compounds and Single Molecule Magnets (SMMs): Synthesis, Structure, and Magnetic Studies
Authors: Zhu Yan , Luo Feng , Feng Xue-Feng , Liao Zhen-Wei , Song Yu-Mei , Huang Hai-Xiao , Tian Xiao-Zhao , Sun Gong-Ming , Luo Ming-Biao
Published: October 2012

In this work, based on mixed N-, O-donor ligands, a series of Co(ii)-Dy(iii) compounds are synthesised and characterised by single crystal X-ray diffraction and magnetic studies. These compounds include Co2(phen)2Dy(PhCOO)7 (1), Co2(phen)2Dy2(PhCOO)10 (2), Co(bpy)Dy(H2O)(CH3-PhCOO)5 (3), Co(phen)Dy(H2O)(CH3-PhCOO)5 (4), Co2(phen)2Dy(NO2-PhCOO)7 (5), Co2(phen)2Dy2(NO2-PhCOO)10 (6), and Co2(bpy)2Dy2(NO2-PhCOO)10 (7), where phen, bpy, CH3-PhCOOH, and NO2-PhCOOH are 1,10-phenanthroline, 2,2′-bipyridine, 3-methylbenzoic acid, and 3-nitrobenzoic acid, respectively. In these cases, di-, tri-, and tetranuclear Co-Dy clusters are observed. Direct current (DC) magnetic susceptibility reveals ferromagnetic or antiferromagnetic behaviour, whilst dynamic magnetic studies disclose single molecule magnet (SMM)-like slow magnetic relaxation for most of these compounds.
Alternative ground states enable pathway switching in biological electron transfer
Authors: Abriata Luciano A. , Álvarez-Paggi Damián , Ledesma Gabriela N. , Blackburn Ninian J. , Vila Alejandro J. , Murgida Daniel H.
Published: October 2012

Electron transfer is the simplest chemical reaction and constitutes the basis of a large variety of biological processes, such as photosynthesis and cellular respiration. Nature has evolved specific proteins and cofactors for these functions. The mechanisms optimizing biological electron transfer have been matter of intense debate, such as the role of the protein milieu between donor and acceptor sites. Here we propose a mechanism regulating long-range electron transfer in proteins. Specifically, we report a spectroscopic, electrochemical, and theoretical study on WT and single-mutant Cu
A
redox centers from
Thermus thermophilus
, which shows that thermal fluctuations may populate two alternative ground-state electronic wave functions optimized for electron entry and exit, respectively, through two different and nearly perpendicular pathways. These findings suggest a unique role for alternative or “invisible” electronic ground states in directional electron transfer. Moreover, it is shown that this energy gap and, therefore, the equilibrium between ground states can be fine-tuned by minor perturbations, suggesting alternative ways through which protein–protein interactions and membrane potential may optimize and regulate electron–proton energy transduction.
Structural basis for the recognition and cleavage of abasic DNA in
Neisseria meningitidis
Authors: Lu Duo , Silhan Jan , MacDonald James T. , Carpenter Elisabeth P. , Jensen Kirsten , Tang Christoph M. , Baldwin Geoff S. , Freemont Paul S.
Published: October 2012

Base excision repair (BER) is a highly conserved DNA repair pathway throughout all kingdoms from bacteria to humans. Whereas several enzymes are required to complete the multistep repair process of damaged bases, apurinic-apyrimidic (AP) endonucleases play an essential role in enabling the repair process by recognizing intermediary abasic sites cleaving the phosphodiester backbone 5′ to the abasic site. Despite extensive study, there is no structure of a bacterial AP endonuclease bound to substrate DNA. Furthermore, the structural mechanism for AP-site cleavage is incomplete. Here we report a detailed structural and biochemical study of the AP endonuclease from
Neisseria meningitidis
that has allowed us to capture structural intermediates providing more complete snapshots of the catalytic mechanism. Our data reveal subtle differences in AP-site recognition and kinetics between the human and bacterial enzymes that may reflect different evolutionary pressures.
Structural basis for promiscuity and specificity during
Candida glabrata
invasion of host epithelia
Authors: Maestre-Reyna Manuel , Diderrich Rike , Veelders Maik Stefan , Eulenburg Georg , Kalugin Vitali , Brückner Stefan , Keller Petra , Rupp Steffen , Mösch Hans-Ulrich , Essen Lars-Oliver
Published: October 2012

The human pathogenic yeast
Candida glabrata
harbors more than 20 surface-exposed, epithelial adhesins (Epas) for host cell adhesion. The Epa family recognizes host glycans and discriminates between target tissues by their adhesin (A) domains, but a detailed structural basis for ligand-binding specificity of Epa proteins has been lacking so far. In this study, we provide high-resolution crystal structures of the Epa1A domain in complex with different carbohydrate ligands that reveal how host cell mucin-type
O
-glycans are recognized and allow a structure-guided classification of the Epa family into specific subtypes. Further detailed structural and functional characterization of subtype-switched Epa1 variants shows that specificity is governed by two inner loops, CBL1 and CBL2, involved in calcium binding as well as by three outer loops, L1, L2, and L3. In summary, our study provides the structural basis for promiscuity and specificity of Epa adhesins, which might further contribute to developing anti-adhesive antimycotics and combating
Candida
colonization.
Cardiomyocytes from AKAP7 knockout mice respond normally to adrenergic stimulation
Authors: Jones Brian W. , Brunet Sylvain , Gilbert Merle L. , Nichols C. Blake , Su Thomas , Westenbroek Ruth E. , Scott John D. , Catterall William A. , McKnight G. Stanley
Published: October 2012

Protein kinase A (PKA) is activated during sympathetic stimulation of the heart and phosphorylates key proteins involved in cardiac Ca
2+
handling, including the L-type Ca
2+
channel (Ca
V
1.2) and phospholamban (PLN). This results in acceleration and amplification of the beat-to-beat changes in cytosolic Ca
2+
in cardiomyocytes and, in turn, an increased rate and force of contraction. PKA is held in proximity to its substrates by protein scaffolds called A kinase anchoring proteins (AKAPs). It has been suggested that the short and long isoforms of AKAP7 (also called AKAP15/18) localize PKA in complexes with Ca
V
1.2 and PLN, respectively. We generated an AKAP7 KO mouse in which all isoforms were deleted and tested whether Ca
2+
current, intracellular Ca
2+
concentration, or Ca
2+
reuptake were impaired in isolated adult ventricular cardiomyocytes following stimulation with the β-adrenergic agonist isoproterenol. KO cardiomyocytes responded normally to adrenergic stimulation, as measured by whole-cell patch clamp or a fluorescent intracellular Ca
2+
indicator. Phosphorylation of Ca
V
1.2 and PLN were also unaffected by genetic deletion of AKAP7. Immunoblot and RT-PCR revealed that only the long isoforms of AKAP7 were detectable in ventricular cardiomyocytes. The results indicate that AKAP7 is not required for regulation of Ca
2+
handling in mouse cardiomyocytes.
Effects of Heat Stress During Grain Filling on the Functional Properties of Flour from Fresh Waxy Maize
Authors: Lu Dalei , Lu Weping
Published: October 2012

The effects of temperature during grain filling on the quality of fresh waxy maize grain were investigated using three varieties. Plants of the selected varieties were subjected to two temperature treatments, namely, control (mean daily air temperature, 30°C) and heat stress (35°C), after artificial pollination (1–23 days after pollination). Heat stress decreased starch content and crystallinity and increased the contents of protein and protein fractions (albumin, globulin, zein, and glutenin), but it did not affect soluble sugar content in general. The effects of heat stress on grain textural characteristics were variety dependent, except for springiness, which was similar between treatments. Pasting and thermal properties were also affected by heat stress. The results suggest that heat stress during grain filling changes the composition of flour and crystalline structure of starch, thereby decreasing viscosities and enthalpies of gelatinization as well as increasing the pasting and gelatinization temperature of fresh waxy maize.
Toward Understanding the Role of Aphid Effectors in Plant Infestation
Authors: Rodriguez Patricia A. , Bos Jorunn I. B.
Published: October 2012

In recent years, immense progress has been made toward understanding the functions of effectors from a range of plant pathogens, such as oomycetes, fungi, bacteria, and nematodes. Like plant pathogens, aphids form close associations with host plants, featuring signal exchange between the two organisms. While feeding and probing, aphids deliver effector proteins mixed with saliva directly into the host–stylet interface. With the increasing availability of aphid genome and transcriptome sequence data, aphid effector biology is emerging as a new and exciting area of research. In this review, we provide an overview of recent advances in the aphid effector biology field and highlight some of the current questions.