bluuebunny/crossref_metadata_2025 huggingface dataset:
Intergenerational differences in acculturation experiences, food beliefs and perceived health risks among refugees from the Horn of Africa in Melbourne, Australia
Authors: Wilson Alyce , Renzaho Andre
Published: January 2014

Objective

To investigate the differences in acculturation experiences between parent and adolescent refugees from the Horn of Africa in Melbourne, Australia and to explore food beliefs and perceived health risks from an intergenerational perspective.

Design

Qualitative cross-sectional study involving a combination of semi-structured one-on-one interviews and focus group discussions.

Setting

North-West suburbs of Melbourne, Australia.

Subjects

Eritrean, Ethiopian, Somali and Sudanese refugees.

Results

Using a purposeful sampling technique, twelve semi-structured face-to-face interviews (nine adults and three adolescents) and four in-depth focus groups (two with adolescents each containing six participants and two with adults one containing six participants and the other ten participants) were carried out. Thus overall data were obtained on fifteen adolescents and twenty-five parents. Qualitative analysis identified differences between parents and adolescents in relation to lifestyle, diet and physical activity. Views regarding health consequences of their changed diets also differed. Parental feeding practices encompassed a variety of methods and were enforced in an attempt by parents to control their children's dietary behaviours and prevent their drift away from traditional eating habits.

Conclusions

These findings call for more research to contextualise dietary acculturation among refugee youth and the impact of migration on parenting styles and feeding practices in communities from the Horn of Africa. Preventive health programmes with Horn of Africa refugees need to acknowledge the effect of acculturation on diet and physical activity levels and a socio-cultural framework needs to be developed with respect to the importance and influence of the family environment.
The Application of Off-Axis Electron Holography to Electrically Biased Single GaN Nanowires for Electrical Resistivity Measurement
Authors: Yazdi S. , Kasama T. , Beleggia M. , Ciechonski R. , Kryliouk O. , Wagner J.B.
Published: January 2014

Extended abstract of a paper presented at Microscopy and Microanalysis 2013 in Indianapolis, Indiana, USA, August 4 – August 8, 2013.
Disentangling planetary orbits from stellar activity in radial-velocity surveys
Authors: Haywood R. D. , Cameron A. Collier , Queloz D. , Barros S.C.C. , Deleuil M. , Fares R. , Gillon M. , Hatzes A. , Lanza A.F. , Lovis C. , Moutou C. , Pepe F. , Pollacco D. , Santerne A. , Ségransan D. , Unruh Y.
Published: January 2014

The majority of extra-solar planets have been discovered (or confirmed after follow-up) through radial-velocity (RV) surveys. Using ground-based spectrographs such as High Accuracy Radial Velocity Planetary Search (HARPS) and HARPS-North, it is now possible to detect planets that are only a few times the mass of the Earth. However, the presence of dark spots on the stellar surface produces RV signals that are very similar in amplitude to those caused by orbiting low-mass planets. Disentangling these signals has thus become the biggest challenge in the detection of Earth-mass planets using RV surveys. To do so, we use the star's lightcurve to model the RV variations produced by spots. Here we present this method and show the results of its application to CoRoT-7.
Personality Disorders and Long-Term Sick Leave: A Population-Based Study of Young Adult Norwegian Twins
Authors: Gjerde Line C. , Røysamb Espen , Czajkowski Nikolai , Knudsen Gun Peggy , Østby Kristian , Tambs Kristian , Kendler Kenneth S. , Reichborn-Kjennerud Ted , Ørstavik Ragnhild E.
Published: January 2014

Personality disorders (PDs) reduce global functioning, are associated with high levels of work disability, and are thus also likely to influence long-term sick leave (LTSL). Previous research has indicated significant genetic influence on both DSM-IV PDs and LTSL. To what degree genes contributing to PDs also influence LTSL has not been investigated. The aims of the current study were to investigate which PDs were significantly associated with LTSL, to what extent the genetic contributions to these PDs account for the heritability of LTSL, and to explore the hypothesis of a causal association between PDs and LTSL. The sample consisted of 2,771 young, adult Norwegian twins, born 1967–1979. PDs were assessed using the Structured Interview for DSM-IV Personality (SIDP-IV). The age range for the interview was 20–32. The data were subsequently linked to public records of LTSL (sick leave >16 days) up to 11 years later. The odds ratio for being in the highest LTSL category (>15% sick leave) when fulfilling the DSM-IV criteria for any PD diagnosis was 2.6 (1.8–3.8, 95% CI). Dimensional representations of schizotypal, paranoid, and borderline PD were independently and significantly associated with LTSL. The heritability of LTSL was 0.50. Genetic factors shared with the PDs accounted for 20% of this. The association between PDs and LTSL was due to shared genetic and not environmental influences, and was mainly explained by one common genetic factor. The hypothesis of a causal association was not supported, indicating that the association is explained by overlapping genetic liability between PDs and LTSL.
Embodied social interaction constitutes social cognition in pairs of humans: A minimalist virtual reality experiment
Authors: Froese Tom , Iizuka Hiroyuki , Ikegami Takashi
Published: January 2014

Scientists have traditionally limited the mechanisms of social cognition to one brain, but recent approaches claim that interaction also realizes cognitive work. Experiments under constrained virtual settings revealed that interaction dynamics implicitly guide social cognition. Here we show that embodied social interaction can be constitutive of agency detection and of experiencing another's presence. Pairs of participants moved their “avatars” along an invisible virtual line and could make haptic contact with three identical objects, two of which embodied the other's motions, but only one, the other's avatar, also embodied the other's contact sensor and thereby enabled responsive interaction. Co-regulated interactions were significantly correlated with identifications of the other's avatar and reports of the clearest awareness of the other's presence. These results challenge folk psychological notions about the boundaries of mind, but make sense from evolutionary and developmental perspectives: an extendible mind can offload cognitive work into its environment.
Optimization of experimental conditions by orthogonal test design in a laser-induced breakdown experiment to analyze aluminum alloys
Authors: Zheng Peichao , Liu Hongdi , Wang Jinmei , Yu Bin , Zhang Bin , Yang Rui , Wang Xiaomeng
Published: January 2014

The orthogonal test design was used to optimize the parameters of aluminum alloy LIBS.
Synthesis of niobium oxide nanowires by polyethylenimine as template at varying pH values
Authors: Zhang Zhenwei , Zhang Geng , He Lin , Sun Long , Jiang Xingmao , Yun Zhi
Published: January 2014

Nb2O5 nanowires were synthesized by a hydrothermal method using polyethylenimine as a soft template. The results indicated that the pH value greatly affected the Nb2O5 nanowires.
Theoretical 57Fe Mössbauer spectroscopy: isomer shifts of [Fe]-hydrogenase intermediates
Authors: Hedegård Erik Donovan , Knecht Stefan , Ryde Ulf , Kongsted Jacob , Saue Trond
Published: January 2014

A computational protocol for 57Fe isomer shifts, based on the relativistic eXact 2-Component Hamiltonian (X2C), is applied to discriminate between proposed intermediates of [Fe]-hydrogenase. Detailed analysis reveals that the difference in isomer shifts between two intermediates is due to an overlap effect.
Graphene oxide dispersions: tuning rheology to enable fabrication
Authors: Naficy Sina , Jalili Rouhollah , Aboutalebi Seyed Hamed , Gorkin III Robert A. , Konstantinov Konstantin , Innis Peter C. , Spinks Geoffrey M. , Poulin Philippe , Wallace Gordon G.
Published: January 2014

Ultra-large graphene oxide sheets exhibit unique viscoelastic properties, making them a new class of soft material. We provide fundamental insights enabling development of various fabrication techniques utilizing this 2D material.
A comparative study of the molecular structure, lipophilicity, solubility, acidity, absorption and polar surface area of coumarinic anticoagulants and direct thrombin inhibitors
Authors: Remko Milan , Broer Ria , Remková Anna
Published: January 2014

The methods of computational chemistry have been used to elucidate the molecular properties of coumarinic anticoagulants (acenocoumarol, phenprocoumon, warfarin and tecarfarin) and direct thrombin inhibitors (melagatran, dabigatran and their prodrug forms).
First total synthesis of fuzanins C, D and their analogues as anticancer agents
Authors: Kumar S. Naveen , Pavan Kumar C. H. N. S. Sai , Srihari E. , Kancharla Sravani , Srinivas Kolupula , Shrivastava Shweta , Naidu V. G. M. , Jayathirtha Rao V.
Published: January 2014

Total synthesis of fuzanins C, D and their quinoline analogues has been accomplished from readily available starting materials. Synthesis of fuzanin D described here also serves to establish its absolute configuration. All compounds were screened for anticancer activity on four cancer cell lines. The quinoline analogues 4d, 4c, 3c are relatively more potent.
Cellulose fibres with carbon nanotube networks for water sensing
Authors: Qi Haisong , Liu Jianwen , Deng Yinhu , Gao Shanglin , Mäder Edith
Published: January 2014

Cellulose-based fibres with unique and efficient abilities to sense liquid water were realized by depositing multi-walled carbon nanotubes (MWNTs) on the surfaces of the fibres using a simple and scalable dip coating.
Tailor-made gemcitabine prodrug nanoparticles from well-defined drug–polymer amphiphiles prepared by controlled living radical polymerization for cancer chemotherapy
Authors: Wang Weiwei , Li Chen , Zhang Ju , Dong Anjie , Kong Deling
Published: January 2014

Novel prodrug nanoparticles with a tailorable high drug payload and in vivo anti-cancer activity assembled from well-defined gemcitabine–polymer conjugate amphiphiles prepared by RAFT polymerization are presented.
Cytokine networking of innate immunity cells: a potential target of therapy
Authors: Striz Ilja , Brabcova Eva , Kolesar Libor , Sekerkova Alena
Published: January 2014

Innate immune cells, particularly macrophages and epithelial cells, play a key role in multiple layers of immune responses. Alarmins and pro-inflammatory cytokines from the IL (interleukin)-1 and TNF (tumour necrosis factor) families initiate the cascade of events by inducing chemokine release from bystander cells and by the up-regulation of adhesion molecules required for transendothelial trafficking of immune cells. Furthermore, innate cytokines produced by dendritic cells, macrophages, epithelial cells and innate lymphoid cells seem to play a critical role in polarization of helper T-cell cytokine profiles into specific subsets of Th1/Th2/Th17 effector cells or regulatory T-cells. Lastly, the innate immune system down-regulates effector mechanisms and restores homoeostasis in injured tissue via cytokines from the IL-10 and TGF (transforming growth factor) families mainly released from macrophages, preferentially the M2 subset, which have a capacity to induce regulatory T-cells, inhibit the production of pro-inflammatory cytokines and induce healing of the tissue by regulating extracellular matrix protein deposition and angiogenesis. Cytokines produced by innate immune cells represent an attractive target for therapeutic intervention, and multiple molecules are currently being tested clinically in patients with inflammatory bowel disease, rheumatoid arthritis, systemic diseases, autoinflammatory syndromes, fibrosing processes or malignancies. In addition to the already widely used blockers of TNFα and the tested inhibitors of IL-1 and IL-6, multiple therapeutic molecules are currently in clinical trials targeting TNF-related molecules [APRIL (a proliferation-inducing ligand) and BAFF (B-cell-activating factor belonging to the TNF family)], chemokine receptors, IL-17, TGFβ and other cytokines.
Parity violation in nuclear magnetic resonance frequencies of chiral tetrahedral tungsten complexes NWXYZ (X, Y, Z = H, F, Cl, Br or I)
Authors: Nahrwold Sophie , Berger Robert , Schwerdtfeger Peter
Published: January 2014

Density functional theory within the two-component quasi-relativistic zeroth-order regular approximation (ZORA) is used to predict parity violation shifts in 183W nuclear magnetic resonance shielding tensors of chiral, tetrahedrally bonded tungsten complexes of the form NWXYZ (X, Y, Z = H, F, Cl, Br or I), as well as for the heavier systems NWHAtF and NWH(117)F for comparison. The calculations reveal that sub-mHz accuracy is required to detect such tiny effects in this class of compounds, and that parity violation effects are very sensitive to the choice of ligands.
Shock Hugoniot equations of state for binary water-alcohol liquid mixtures
Authors: Schulze Peter A. , Ivanov Trevor W. , Bolme Cynthia A. , Brown Kathryn E. , McGrane Shawn D. , Moore David S.
Published: January 2014

Shock Hugoniot data were obtained using laser generated shock and ultrafast dynamic ellipsometry (UDE) methods for several non-ideal water-alcohol liquid mixtures, with the alcohols being methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, and t-butanol (a.k.a., 2-methyl-2-propanol or tert-butanol). The sound speeds of the mixtures were obtained using Brillouin scattering when not available in the literature. The shock and particle velocities obtained from the UDE data were compared to expectations of the universal liquid Hugoniot (ULH) and to literature shock (plate impact) data where available. The ethanol/water data were presented in a previous publication [Schulze et al., J. Phys. Chem. A 117, 6158–6163 (2013)]. The shock Hugoniot trends for all these mixtures, here represented as deviations from predictions of the ULH, versus fraction of alcohol are quite similar to each other and suggest that complex hydrogen bonding networks in alcohol-water mixtures alter the compressibility of the mixtures.
Intercomparison of permittivity measurement techniques for ferroelectric thin layers
Authors: Queffelec P. , Laur V. , Chevalier A. , Le Floch J.-M. , Passerieux D. , Cros D. , Madrangeas V. , Le Febvrier A. , Députier S. , Guilloux-Viry M. , Houzet G. , Lacrevaz T. , Bermond C. , Fléchet B.
Published: January 2014

The dielectric properties of a KTa0.65Nb0.35O3 ferroelectric composition for a submicronic thin layer were measured in the microwave domain using different electromagnetic characterization methods. Complementary experimental techniques (broadband methods versus resonant techniques, waveguide versus transmission line) and complementary data processing procedures (quasi-static theoretical approaches versus full-wave analysis) were selected to investigate the best way to characterize ferroelectric thin films. The measured data obtained from the cylindrical resonant cavity method, the experimental method that showed the least sources of uncertainty, were taken as reference values for comparisons with results obtained using broadband techniques. The error analysis on the methods used is discussed with regard to the respective domains of validity for each method; this enabled us to identify the best experimental approach for obtaining an accurate determination of the microwave dielectric properties of ferroelectric thin layers.
Continuous distributions of charges: Extensions of the one component plasma
Authors: Heyes D. M. , Rickayzen G.
Published: January 2014

The electrostatic interaction between finite charge distributions, ρ(r), in a neutralizing background is considered as an extension of the one component plasma (OCP) model of point charges. A general form for the interaction potential is obtained which can be applied to molecular theories of many simple charged fluids and mixtures and to the molecular dynamics (MD) simulation of such systems. The formalism is applied to the study of a fluid of Gaussian charges in a neutralizing background by MD simulation and using hypernetted-chain integral equation theory. The treatment of these interactions is extended to a periodic system using a Fourier Transform formulation and, for a rapidly decaying charge distribution, an application of the Ewald method. The contributions of the self-energy and neutralizing background to the system's energy are explicitly included in the formulation. Calculations reveal differences in behavior from the OCP model when the Wigner-Seitz radius is of order and less than the Gaussian charge density decay length. For certain parameter values these systems can exhibit a multiple occupancy crystalline phase at high density which undergoes re-entrant melting at higher density. An exploration of the effects of the various length scales of the system on the equation of state and radial distribution function is made.
Rigidity of a spherical capsule switches the localization of encapsulated particles between inner and peripheral regions under crowding condition: Simple model on cellular architecture
Authors: Shew Chwen-Yang , Kondo Kenta , Yoshikawa Kenichi
Published: January 2014

We have investigated the inhomogeneous interior of confined spherical cavities as capsules containing encapsulated binary hard sphere mixtures for different compositions and cavity wall rigidity. Such a greatly simplified model manifests the effects of macromolecular crowding arising from excluded volume interactions in a tiny cell or a cellular nucleus. By fixing the number of large particles, the level of crowding is adjusted by changing the amount of small hard spheres in the cavity. For a rigid cavity, large spheres tend to pack in liquid-like order apart from the surface to the center of the cavity as the crowding level is increased. Whereas, for a soft cavity, larger spheres tend to blend with small spheres in the peripheral region at near the boundary of the cavity, and are susceptible to be depleted from the interior of the cavity as the cavity becomes more crowded. These results may help future elucidation of the thermodynamic pathways to stabilize the inhomogeneous structure of mixtures confined in cavities, such as the derepression of genome materials around the interior rim of the nucleus in a cancerous cell.
Dissecting molecular descriptors into atomic contributions in density functional reactivity theory
Authors: Rong Chunying , Lu Tian , Liu Shubin
Published: January 2014

Density functional reactivity theory (DFRT) employs the electron density of a molecule and its related quantities such as gradient and Laplacian to describe its structure and reactivity properties. Proper descriptions at both molecular (global) and atomic (local) levels are equally important and illuminating. In this work, we make use of Bader's zero-flux partition scheme and consider atomic contributions for a few global reactivity descriptors in DFRT, including the density-based quantification of steric effect and related indices. Earlier, we proved that these quantities are intrinsically correlated for atomic and molecular systems [S. B. Liu, J. Chem. Phys. 126, 191107 (2007); ibid. 126, 244103 (2007)]. In this work, a new basin-based integration algorithm has been implemented, whose reliability and effectiveness have been extensively examined. We also investigated a list of simple hydrocarbon systems and different scenarios of bonding processes, including stretching, bending, and rotating. Interesting changing patterns for the atomic and molecular values of these quantities have been revealed for different systems. This work not only confirms the strong correlation between these global reactivity descriptors for molecular systems, as theoretically proven earlier by us, it also provides new and unexpected changing patterns for their atomic values, which can be employed to understand the origin and nature of chemical phenomena.
Shape variation of micelles in polymer thin films
Authors: Zhou Jiajia , Shi An-Chang
Published: January 2014

The equilibrium properties of block copolymer micelles confined in polymer thin films are investigated using self-consistent field theory. The theory is based on a model system consisting of AB diblock copolymers and A homopolymers. Two different methods, based on the radius of gyration tensor and the spherical harmonics expansion, are used to characterize the micellar shape. The results reveal that the morphology of micelles in thin films depends on the thickness of the thin films and the selectivity of the confining surfaces. For spherical (cylindrical) micelles, the spherical (cylindrical) symmetry is broken by the presence of the one-dimensional confinement, whereas the top-down symmetry is broken by the selectivity of the confining surfaces. Morphological transitions from spherical or cylindrical micelles to cylinders or lamella are predicted when the film thickness approaches the micellar size.
Born energy, acid-base equilibrium, structure and interactions of end-grafted weak polyelectrolyte layers
Authors: Nap R. J. , Tagliazucchi M. , Szleifer I.
Published: January 2014

This work addresses the effect of the Born self-energy contribution in the modeling of the structural and thermodynamical properties of weak polyelectrolytes confined to planar and curved surfaces. The theoretical framework is based on a theory that explicitly includes the conformations, size, shape, and charge distribution of all molecular species and considers the acid-base equilibrium of the weak polyelectrolyte. Namely, the degree of charge in the polymers is not imposed but it is a local varying property that results from the minimization of the total free energy. Inclusion of the dielectric properties of the polyelectrolyte is important as the environment of a polymer layer is very different from that in the adjacent aqueous solution. The main effect of the Born energy contribution on the molecular organization of an end-grafted weak polyacid layer is uncharging the weak acid (or basic) groups and consequently decreasing the concentration of mobile ions within the layer. The magnitude of the effect increases with polymer density and, in the case of the average degree of charge, it is qualitatively equivalent to a small shift in the equilibrium constant for the acid-base equilibrium of the weak polyelectrolyte monomers. The degree of charge is established by the competition between electrostatic interactions, the polymer conformational entropy, the excluded volume interactions, the translational entropy of the counterions and the acid-base chemical equilibrium. Consideration of the Born energy introduces an additional energetic penalty to the presence of charged groups in the polyelectrolyte layer, whose effect is mitigated by down-regulating the amount of charge, i.e., by shifting the local-acid base equilibrium towards its uncharged state. Shifting of the local acid-base equilibrium and its effect on the properties of the polyelectrolyte layer, without considering the Born energy, have been theoretically predicted previously. Account of the Born energy leads to systematic, but in general small, corrections to earlier theoretical predictions describing the behavior of weak polyelectrolyte layers. However, polyelectrolyte uncharging results in a decrease in the concentration of counterions and inclusion of the Born Energy can result in a substantial decrease of the counterion concentration. The effect of considering the Born energy contribution is explored for end-grafted weak polyelectrolyte layers by calculating experimental observables which are known to depend on the presence of charges within the polyelectrolyte layer: inclusion of the Born energy contribution leads to a decrease in the capacitance of polyelectrolyte-modified electrodes, a decrease of conductivity of polyelectrolyte-modified nanopores and an increase in the repulsion exerted by a planar polyelectrolyte layer confined by an opposing wall.
A transition state theory for calculating hopping times and diffusion in highly confined fluids
Authors: Wanasundara Surajith N. , Spiteri Raymond J. , Bowles Richard K.
Published: January 2014

Monte Carlo simulation is used to study the dynamical crossover from single file diffusion to normal diffusion in fluids confined to narrow channels. We show that the long time diffusion coefficients for a series of systems involving hard and soft interaction potentials can be described in terms of a hopping time that measures the time it takes for a particle to escape the cage formed by its neighbors in the pore. Free energy barriers for the particle hopping process are calculated and used to show that transition state theory effectively describes the hopping time for all the systems studied over a range of pore radii. Our work suggests that the combination of hopping times and transition state theory offers a useful and general framework to describe the dynamics of highly confined, single file fluids.
Smallest fullerene-like silicon cage stabilized by a V2 unit
Authors: Xu Hong-Guang , Kong Xiang-Yu , Deng Xiao-Jiao , Zhang Zeng-Guang , Zheng Wei-Jun
Published: January 2014

We conducted a combined anion photoelectron spectroscopy and density functional theory study on V2Si20 cluster. Our results show that the V2Si20 cluster has an elongated dodecahedron cage structure with a V2 unit encapsulated inside the cage. It is the smallest fullerene-like silicon cage and can be used as building block to make cluster-assembled materials, such as pearl-chain style nanowires.
Extreme sub-threshold swing in tunnelling relays
Authors: AbdelGhany M. , Szkopek T.
Published: January 2014

We propose and analyze the theory of the tunnelling relay, a nanoscale active device in which tunnelling current is modulated by electromechanical actuation of a suspended membrane above a fixed electrode. The tunnelling current is modulated exponentially with vacuum gap length, permitting an extreme sub-threshold swing of ∼10 mV/decade breaking the thermionic limit. The predicted performance suggests that a significant reduction in dynamic energy consumption over conventional field effect transistors is physically achievable.
Electronic properties of InP (001)/HfO2 (001) interface: Band offsets and oxygen dependence
Authors: KC Santosh , Dong Hong , Longo Roberto C. , Wang Weichao , Xiong Ka , Wallace Robert M. , Cho Kyeongjae
Published: January 2014

Using ab-initio methods, atomic structures and electronic properties of InP (001)/HfO2 (001) interface are studied within the framework of density functional theory. We examine the InP/HfO2 model interface electronic structures under varying oxidation conditions. The effects of indium and phosphorous concentrations on interfacial bonding, defect states, band offsets, and the thermodynamic stability at the interface are also investigated. The origin of interfacial gap states in InP (001)/HfO2 (001) interface are proposed, mainly from the P-rich oxides, which is validated by our experimental work. This highlights the importance of surface passivation prior to high-κ deposition based on the in situ spectroscopic results of atomic layer deposition of HfO2 on InP.
Effect of defocusing on picosecond laser-coupling into gold cones
Authors: Bush I. A. , Thomas A. G. R. , Gartside L. , Sarfraz S. , Wagenaars E. , Green J. S. , Notley M. , Lowe H. , Spindloe C. , Winstone T. , Robinson A. P. L. , Clarke R. , Ma T. , Yabuuchi T. , Wei M. , Beg F. N. , Stephens R. B. , MacPhee A. , MacKinnon A. J. , Key M. H. , Nazarov W. , Sherlock M. , Pasley J.
Published: January 2014

Here, we show that defocusing of the laser in the interaction of a picosecond duration, 1.053 μm wavelength, high energy pulse with a cone-wire target does not significantly affect the laser energy coupling efficiency, but does result in a drop in the fast electron effective temperature. This may be beneficial for fast ignition, since not only were more electrons with lower energies seen in the experiment but also the lower prepulse intensity will reduce the amount of preplasma present on arrival of the main pulse, reducing the distance the hot electrons have to travel. We used the Vulcan Petawatt Laser at the Rutherford Appleton Laboratory and gold cone targets with approximately 1 mm long, 40 μm diameter copper wires attached to their tip. Diagnostics included a quartz crystal imager, a pair of highly oriented pyrolytic graphite crystal spectrometers and a calibrated CCD operating in the single photon counting regime, all of which looked at the copper Kα emission from the wire. A short pulse optical probe, delayed 400 ps relative to the main pulse was employed to diagnose the extent of plasma expansion around the wire. A ray-tracing code modeled the change in intensity on the interior surface of the cone with laser defocusing. Using a model for the wire copper Kα emission coupled to a hybrid Vlasov-Fokker-Planck code, we ran a series of simulations, holding the total energy in electrons constant whilst varying the electron temperature, which support the experimental conclusions.
Photoluminescence studies of Y2O3:Eu3+ under high pressure
Authors: Zhang Jian , Cui Hang , Zhu Peifen , Ma Chunli , Wu Xiaoxin , Zhu Hongyang , Ma Yanzhang , Cui Qiliang
Published: January 2014

The Eu-doped yttria (Y2O3:Eu3+) has been investigated by the in situ high-pressure angle dispersive synchrotron X-ray diffraction (XRD) and the photoluminescence (PL) spectroscopy. The red shift and intensity ratio variation of emissions with increasing pressure were observed and elucidated. It was found that the red shift of emissions is related to the expansion of the f orbit of the Eu3+ and the intensity ratio variation of emissions is ascribed to the change of the crystal field under high pressure. The pressure-induced changes in spectrum are related to the phase transition, which was confirmed by XRD pattern. The two high pressure phases were identified as the monoclinic (C2/m) phase and hexagonal (P-3m1) phase by the Rietveld refinement.
Characterization of superconducting radiofrequency breakdown by two-mode excitation
Authors: Eremeev G. , Palczewski A. D.
Published: January 2014

We show that thermal and magnetic contributions to the breakdown of superconductivity in radiofrequency (RF) fields can be separated by applying two RF modes simultaneously to a superconducting surface. We develop a simple model that illustrates how mode-mixing RF data can be related to properties of the superconductor. Within our model the data can be described by a single parameter, which can be derived either from RF or thermometry data. Our RF and thermometry data are in good agreement with the model. We propose to use mode-mixing technique to decouple thermal and magnetic effects on RF breakdown of superconductors.
Optical power of semiconductor lasers with a low-dimensional active region
Authors: Asryan Levon V. , Sokolova Zinaida N.
Published: January 2014

A comprehensive analytical model for the operating characteristics of semiconductor lasers with a low-dimensional active region is developed. Particular emphasis is given to the effect of capture delay of both electrons and holes from a bulk optical confinement region into a quantum-confined active region and an extended set of rate equations is used. We derive a closed-form expression for the internal quantum efficiency as an explicit function of the injection current and parameters of a laser structure. Due to either electron or hole capture delay, the internal efficiency decreases with increasing injection current above the lasing threshold thus causing sublinearity of the light-current characteristic of a laser.
Microwave plasma enhanced chemical vapor deposition of nanocrystalline diamond films by bias-enhanced nucleation and bias-enhanced growth
Authors: Chu Yueh-Chieh , Tzeng Yonhua , Auciello Orlando
Published: January 2014

Effects of biasing voltage-current relationship on microwave plasma enhanced chemical vapor deposition of ultrananocrystalline diamond (UNCD) films on (100) silicon in hydrogen diluted methane by bias-enhanced nucleation and bias-enhanced growth processes are reported. Three biasing methods are applied to study their effects on nucleation, growth, and microstructures of deposited UNCD films. Method A employs 320 mA constant biasing current and a negative biasing voltage decreasing from −490 V to −375 V for silicon substrates pre-heated to 800 °C. Method B employs 400 mA constant biasing current and a decreasing negative biasing voltage from −375 V to −390 V for silicon pre-heated to 900 °C. Method C employs −350 V constant biasing voltage and an increasing biasing current up to 400 mA for silicon pre-heated to 800 °C. UNCD nanopillars, merged clusters, and dense films with smooth surface morphology are deposited by the biasing methods A, B, and C, respectively. Effects of ion energy and flux controlled by the biasing voltage and current, respectively, on nucleation, growth, microstructures, surface morphologies, and UNCD contents are confirmed by scanning electron microscopy, high-resolution transmission-electron-microscopy, and UV Raman scattering.
On the optimal performance and universal design curves of galloping energy harvesters
Authors: Bibo A. , Daqaq M. F.
Published: January 2014

In this letter, we establish a universal relationship between a dimensionless version of the output power and the flow speed for galloping energy harvesters. This relationship yields a unique curve, which is only sensitive to the aerodynamic properties of the bluff body, but is, otherwise, invariant under any changes in the mechanical and electrical design parameters of the harvester. The curve permits a simple and direct comparative analysis of the energy harvesting performance of different bluff bodies so long that the other design parameters are kept constant. The universal curve is also shown to facilitate the optimization analysis, thereby providing significant insight into the optimal performance conditions.
A multi-scale analysis of the crystallization of amorphous germanium telluride using ab initio simulations and classical crystallization theory
Authors: Liu Jie , Xu Xu , Brush Lucien , Anantram M. P.
Published: January 2014

The crystallization properties of the prototypical binary phase change material (PCM) germanium telluride (GeTe) are investigated by combining crystallization theory with ab initio molecular dynamics simulations. The temperature dependence of the physical quantities that determine the crystallization properties is calculated and analyzed. It is shown that the critical nucleus radius of a crystalline cluster is smaller than 1.4 nm when the annealing temperature is lower than 600 K, indicating an extremely promising scaling scenario. Our analysis reveals that the elastic energy, which is largely ignored in existing PCM crystallization studies, plays an important role in determining various crystallization properties and the ultimate scaling limit of the PCM. By omitting the influence of elastic energy, the critical formation energy (critical nuclei radius) will be underestimated by 41.7% (22.4%), and the nucleation rate will be overestimated by 74.2% when the annealing temperature is 600 K.
Dynamical mechanism for coercivity tunability in the electrically controlled FePt perpendicular films with small grain size
Authors: Feng Chun , Yang Meiyin , Gong Kui , Li Xujing , Li Baohe , Jiang Yong , Yu Guanghua
Published: January 2014

This article reports property manipulations and related dynamical evolution in electromigration controlled FePt perpendicular films. Through altering voltage and treatment time of the power supply applied on the films, electronic momentum was fleetly controlled to manipulate the kinetic energy of Fe and Pt atoms based on momentum exchanges. The electromigration control behavior was proven to cause steerable ordering degree and grain growth in the films without thermal treatment. Processed FePt films with small grain size, high magnetocrystalline anisotropy, and controllable coercivity can be easily obtained. The results provide a novel method for tuning magnetic properties of other L10 structured films.
Materazzi effect and the strategic use of anger in competitive interactions
Authors: Gneezy Uri , Imas Alex
Published: January 2014

Significance

Emotions play a critical role in social interactions and decision-making. We present evidence that individuals understand the behavioral effects of emotions, particularly anger, and use them strategically in interactions. In our study, individuals competed on a task, and one of them was given the opportunity to anger the other. The first task was strength-based, where we expected anger to improve performance. Other participants competed on a mental task in which we expected anger to impair performance—angering one’s opponent here may benefit the offender. Anger affected behavior in line with our predictions. Importantly, individuals seemed to anticipate this reaction and took the strategic opportunity to anger their counterpart significantly more in the mental task than in the strength task.
Reconciling disagreement over climate–conflict results in Africa
Authors: Hsiang Solomon M. , Meng Kyle C.
Published: January 2014

Significance

Whether climatic changes affect civil conflicts has been the subject of intense academic debate. Much of this controversy originates from a highly cited dispute between a previous PNAS paper—which finds that civil war incidence in sub-Saharan Africa is associated with increasing local temperature—and a subsequent rebuke of this result, also published in PNAS. We reexamine this apparent disagreement by comparing the statistical models from the two papers using formal tests. When we implement the correct statistical procedure, we find that the evidence presented in the second paper is actually consistent with that of the first. We conclude that the original grounds for the dispute over whether the climate–conflict relationship exists were erroneous.
Origin of regenerating tubular cells after acute kidney injury
Authors: Berger Katja , Bangen Jörg-Martin , Hammerich Linda , Liedtke Christian , Floege Jürgen , Smeets Bart , Moeller Marcus Johannes
Published: January 2014

Significance

Acute kidney injury (AKI) is a common and significant clinical problem for which no specific therapy has been developed. There is controversy about the origin of the regenerating tubular cells after AKI. Attention has recently focused on “scattered tubular cells” (STCs), which are by far the best candidate cells for the postulated fixed progenitor population of kidney tubular cells. In the present study, we clarify this question by genetic cell fate labeling using a unique transgenic mouse. We show that STCs may arise from any tubular cell and that these cells do not represent fixed progenitor cells. Rather, upon different injuries, proximal tubular cells transiently acquire the STC phenotype, which we show to have reparative characteristics.
Hierarchical self-assembly of a striped gyroid formed by threaded chiral mesoscale networks
Authors: Kirkensgaard Jacob J. K. , Evans Myfanwy E. , de Campo Liliana , Hyde Stephen T.
Published: January 2014

Significance

Chirality and hierarchical ordering are two fundamental properties found in many of nature’s most complex self-assembled structures such as living cells. Simultaneous control over these properties in synthetic systems is vital to mimic or even surpass nature’s designs. Via numerical simulations, we describe a class of complex morphologies that afford radically new architectures for self-assembled shapes. Specifically, a mixture of two star block-copolymers are shown to form multiple interwoven 2D and 3D labyrinths—all chiral—and hierarchically ordered on two different length scales. Furthermore, we show that such intricate network morphologies forming at a confined, hyperbolic interface can be classified and modeled in terms of a much simpler isotropic model of packing based on tilings of the hyperbolic plane.
Structure of the
Helicobacter pylori
CagA oncoprotein bound to the human tumor suppressor ASPP2
Authors: Nešić Dragana , Buti Ludovico , Lu Xin , Stebbins C. Erec
Published: January 2014

Significance

Helicobacter pylori
is the greatest risk factor for gastric adenocarcinoma and has been classified as a carcinogen by the World Health Organization. Cytotoxin associated gene A (CagA) is the primary virulence determinant of
H. pylori
and is sufficient to induce tumor formation in animal models. We show here that the host tumor suppressor Apoptosis-stimulating Protein of p53-2 (ASPP2) binds robustly to an N-terminal domain of CagA and elucidate the crystal structure of this complex, revealing the details of the CagA–ASPP2 interaction. Structure-based mutagenesis disrupts this complex in vitro and in cells. Furthermore, we show that the CagA–ASPP2 interaction modulates critical ASPP2 functions, such as p53-binding and apoptosis of
H. pylori
-infected cells.
Pelvic girdle and fin ofTiktaalik roseae
Authors: Shubin Neil H. , Daeschler Edward B. , Jenkins Farish A.
Published: January 2014

Significance

The earliest tetrapods have robust limbs, particularly hind limbs that are enlarged and supported by a number of modifications to the pelvic girdle. In contrast, the closest relatives of tetrapods maintain small and weakly ossified pelvic appendages as compared with the pectorals. This observation has led to the “front wheel drive” hypothesis that held that the closest relatives of tetrapods emphasized pectoral support and locomotion whereas significant pelvic support and locomotion was a tetrapod innovation. The discovery of pelvic girdle and fin material of the tetrapodomorphTiktaalik roseaereveals a transitional stage in the origin of the pelvic girdle and appendage: although retaining primitive skeletal architecture, these elements are enhanced in size and robusticity much like tetrapods.
Combinatorial biosynthesis of sapogenins and saponins in
Saccharomyces cerevisiae
using a C-16α hydroxylase from
Bupleurum falcatum
Authors: Moses Tessa , Pollier Jacob , Almagro Lorena , Buyst Dieter , Van Montagu Marc , Pedreño María A. , Martins José C. , Thevelein Johan M. , Goossens Alain
Published: January 2014

Significance

Saponins are plant molecules that are produced as a chemical defense against herbivores and eukaryotic pathogens. They constitute structurally diverse, bioactive compounds composed of a 30-carbon triterpene backbone adorned with multiple functional groups and sugars. Saikosaponins are abundant saponins accumulating in the Asian medicinal plant
Bupleurum falcatum
, but none of the enzymes involved in their biosynthesis had been characterized. We identified a cytochrome P450 involved in the oxidation of saikosaponins, thereby expanding the enzyme compendium that can generate plant saponins with an extra activity. Using this enzyme compendium, we established a synthetic biology program to reconstitute saponin biosynthesis in the yeast
Saccharomyces cerevisiae
and developed a cyclodextrin-based culturing strategy to sequester triterpenes from engineered yeast cells and enhance their productivity.
Human myocytes are protected from titin aggregation-induced stiffening by small heat shock proteins
Authors: Kötter Sebastian , Unger Andreas , Hamdani Nazha , Lang Patrick , Vorgerd Matthias , Nagel-Steger Luitgard , Linke Wolfgang A.
Published: January 2014

In myocytes, small heat shock proteins (sHSPs) are preferentially translocated under stress to the sarcomeres. The functional implications of this translocation are poorly understood. We show here that HSP27 and αB-crystallin associated with immunoglobulin-like (Ig) domain-containing regions, but not the disordered PEVK domain (titin region rich in proline, glutamate, valine, and lysine), of the titin springs. In sarcomeres, sHSP binding to titin was actin filament independent and promoted by factors that increased titin Ig unfolding, including sarcomere stretch and the expression of stiff titin isoforms. Titin spring elements behaved predominantly as monomers in vitro. However, unfolded Ig segments aggregated, preferentially under acidic conditions, and αB-crystallin prevented this aggregation. Disordered regions did not aggregate. Promoting titin Ig unfolding in cardiomyocytes caused elevated stiffness under acidic stress, but HSP27 or αB-crystallin suppressed this stiffening. In diseased human muscle and heart, both sHSPs associated with the titin springs, in contrast to the cytosolic/Z-disk localization seen in healthy muscle/heart. We conclude that aggregation of unfolded titin Ig domains stiffens myocytes and that sHSPs translocate to these domains to prevent this aggregation.
The role of fisheries and the environment in driving the decline of elasmobranchs in the northern Adriatic Sea
Authors: Barausse Alberto , Correale Vittoria , Curkovic Aleksia , Finotto Licia , Riginella Emilio , Visentin Eleonora , Mazzoldi Carlotta
Published: January 2014

Elasmobranch populations are declining worldwide, calling for urgent assessment of fishery exploitation and application of effective conservation strategies. Here, we applied a novel approach, integrating long-term time-series of landings (1945–2012) and extensive surveys at the fish market of Chioggia, Italy, home of the major fishing fleet of the northern Adriatic Sea, to evaluate the status of elasmobranch populations and fisheries in the one of the most fished Mediterranean basins. The time-series highlight a dramatic decline in elasmobranch landings, particularly for skates and catsharks (Scyliorhinus spp.), whose current catch rates are 2.4 and 10.6% of the average 1940s levels, respectively. These data likely reflect similar large reductions in abundance, as indicated by the analysis of catch-per unit-effort time-series. The biomass of landed skates and catsharks showed regular fluctuations that disappeared after the collapse of the landings. Elasmobranch market composition, assessed through the sampling of 11 900 specimens from 2006 to 2013, included 14 species, but was dominated by just two: Mustelus mustelus and M. punctulatus, which represented more than 60% of the catch. The proportion of sexually immature individuals was generally very high, up to 83% of landed females and 71% of landed males, depending on the species. Although some correlations were detected between landings and local hydrography or climatic indices, the analyses of landings and surveys at the fish market identified fishery exploitation as the main driver of the striking, long-term elasmobranch decline in the northern Adriatic Sea, calling for urgent management actions to improve the conservation status of these fish.
Effects of Thermomechanical Extrusion and Particle Size Reduction on Bioconversion Rate of Corn Fiber for Ethanol Production
Authors: Lin Myat , Ryu Gi‐Hyung
Published: January 2014

The objective of this research was to evaluate the effect of thermomechanical extrusion and particle size (PS) reduction on the bioconversion rate of corn fiber for ethanol production. Extrusion was conducted at a screw speed of 300 rpm, feed rate of 120 g/min, feed moisture content of 30%, melt temperature of 140°C, and die diameter of 3 mm. Raw and extruded corn fiber were separated into three different PSs (1 > PS ≥ 0.5, 0.5 > PS ≥ 0.3, and 0.3 > PS ≥ 0.15 mm) with a wire sieve. Extrusion pretreatment and PS reduction resulted in a significant (P < 0.05) difference in physical properties and color values of extruded corn fiber as a result of accelerated degradation of corn fiber structure. Significant increase in water solubility index of extruded corn fiber at 0.3 > PS ≥ 0.15 mm was an indication of high degradation of starch during extrusion for higher release of polysaccharides. Moreover, extruded corn fiber at PS reduction 0.3 > PS ≥ 0.15 mm also significantly increased (P < 0.05) ethanol yield (69.11 g/L) and conversion (68.18%) by increasing protein digestibility and free amino nitrogen, which are essential for higher fermentation efficiency.