bluuebunny/crossref_metadata_2025 huggingface dataset:
Micrometer long oriented one-dimensional wires and two-dimensional sheets from a bis-urea functionalized dialkoxynaphthalene organogelator
Authors: Maji Subrata , Das Anindita , Sarkar Piyush Kanti , Metya Amaresh , Ghosh Suhrit , Acharya Somobrata
Published: September 2014

Fabrication of 1D wires and 2D sheets of organogelator DAN-U at an air–water interface below the critical gelation concentration is reported here.
In situ growth of novel laminar-shaped Co3S4 as an efficient counter electrode for dye-sensitized solar cells
Authors: Hu Zhelu , Xia Kai , Zhang Jing , Hu Ziyang , Zhu Yuejin
Published: September 2014

Laminar cobalt sulfide (Co3S4) nanosheets are successfully deposited on fluorine doped tin oxide (FTO) substrates by a facile one-step hydrothermal method.
Carbon supported Pt–Sn/SnO2anode catalyst for direct ethanol fuel cells
Authors: Meenakshi S. , Sridhar P. , Pitchumani S.
Published: September 2014

Steady-state performance data of DEFCs (CH3CH2OH and O2) comprising the MEA containing Pt–Sn/SnO2(33 : 7)–C anode catalyst prepared using the decal transfer method.
From TcVII to TcI; facile syntheses of bis-arene complexes [99(m)Tc(arene)2]+ from pertechnetate
Authors: Benz Michael , Braband Henrik , Schmutz Paul , Halter Jonathan , Alberto Roger
Published: September 2014

Bis-arene complexes of technetium represent a fundamental class of organometallic compounds. Detailed insights into their properties are obtained due to novel and convenient synthetic routes.
Hydrodynamic interaction induced spontaneous rotation of coupled active filaments
Authors: Jiang Huijun , Hou Zhonghuai
Published: September 2014

We investigate the coupled dynamics of active filaments with long range hydrodynamic interactions (HI).
The role of temperature in forming sol–gel biocomposites containing polydopamine
Authors: Dyke Jason Christopher , Hu Huamin , Lee Dong Joon , Ko Ching-Chang , You Wei
Published: September 2014

The processing temperature has a big impact on the mechanical properties of HAp-Gemosil composites containing polydopamine.
MEKK2 regulates paxillin ubiquitylation and localization in MDA-MB 231 breast cancer cells
Authors: Ameka Magdalene , Kahle Michael P. , Perez-Neut Mathew , Gentile Saverio , Mirza Ahmed A. , Cuevas Bruce D.
Published: September 2014

The intracellular kinase MEKK2 (mitogen-activated protein kinase/extracellular-signal-regulated kinase kinase kinase 2) is an upstream regulator of JNK (c-Jun N-terminal kinase), but additional functions for MEKK2 have not been well defined. Silencing MEKK2 expression in invasive breast tumour cells markedly inhibits xenograft metastasis, indicating that MEKK2 controls tumour cell function required for tumour progression. In our previous investigation of MEKK2 function, we discovered that tumour cell attachment to fibronectin recruits MEKK2 to focal adhesion complexes, and that MEKK2 knockdown is associated with stabilized focal adhesions and significant inhibition of tumour cell migration. In the present study we investigate MEKK2 function in focal adhesions and we report that MEKK2 physically associates with the LD1 motif of the focal adhesion protein paxillin. We reveal that MEKK2 induces paxillin ubiquitylation, and that this function requires both the paxillin LD1 motif and MEKK2 kinase activity. Finally, we demonstrate that MEKK2 promotes paxillin redistribution from focal adhesions into the cytoplasm, but does not promote paxillin degradation. Taken together, our results reveal a novel function for MEKK2 as a regulator of ubiquitylation-dependent paxillin redistribution in breast tumour cells.
Electromagnetic field strength in proximity of WLAN devices during data and video file transmission
Authors: Miclaus S. , Bechet P.
Published: September 2014

Wireless local area network (WLAN) devices emitting in the 2.4 GHz band may raise questions concerning human exposure mainly when a person stands near an antenna. Proximity far‐field level variation with distance, in the range 40 cm to 1 m is investigated experimentally in order to extract peculiarities of the radiated field in comparison with theoretical predictions. Electric field strength depends on the method of measurement (not yet standardised for quasi‐stochastic signals) and on some key characteristics of transmission. The field level proved to differ from theory: it is lower than predicted and it does not always follow the inverse law with distance. The time–amplitude and the duty‐cycle methods of weighting to obtain a realistic field level allowed highlighting the dependence of the field strength on the traffic direction, on the type of the transmitted file and on the actual data rate and its statistical distribution. In the proximity of access points, downloading conducts to the highest fields, whereas near laptops, uploading does this. A data file transfer implies a higher level of exposure than a video file transfer, but one should consider the data rate dispersion. The proximity field does not significantly depend on the distances between the WLAN devices.
Distributed feedback 3.27 µm diode lasers with continuous‐wave output power above 15 mW at room temperature
Authors: Liang R. , Hosoda T. , Shterengas L. , Stein A. , Lu M. , Kipshidze G. , Belenky G.
Published: September 2014

GaSb‐based type‐I quantum well laterally coupled distributed feedback diode lasers emitting in the methane absorption band near 3.27 µm were designed and fabricated. The first‐order index grating with a period of 480 nm was defined by e‐beam lithography and etched on both sides of 6 µm‐wide shallow ridge waveguide. Coated 2 mm‐long devices demonstrated stable continuous‐wave single‐frequency operation in a wide temperature range with an output power of 15 mW at +17°C and 40 mW at −20°C. The Bragg wavelength temperature tuning rate was ∼0.27 nm/K.
Cooperative transmission schemes for energy‐efficient collaborative wireless sensor networks
Authors: Naeem Muhammad Kamran , Patwary Mohammad Nuruzzaman , Soliman Abdel‐Hamid , Abdel‐Maguid Mohamed
Published: September 2014

Energy conservation is one of the prime concerns that leads the researcher to investigate collaborative wireless sensor networks with some application specific challenges. Such challenges include combining distributed data synchronously, performing power aware signal processing, defining communication methods that can provide progressive accuracy and, optimising processing and communication for signal transmission. A cooperative resource selection and transmission scheme is proposed to improve the performance of collaborative wireless sensor networks in terms of maintaining link reliability. A measure of Channel Quality Index (CQI) is also proposed to obtain dynamic adaptivity and to optimise resource usage within wireless sensor networks according to environment conditions. As part of the proposed cooperative nature of transmission, the recently proposed transmit‐receive antenna selection scheme and lattice reduction algorithm have also been considered. It is assumed that channel state information (CSI) is estimated at receiver and also there is a feedback link between the wireless sensing nodes and the fusion centre receiver. From the simulation results it is observed that for 99.99% detection reliability, the proposed adaptive transmission scheme and proposed hybrid scheme consume only 15% and 18% of energy respectively as compared to the conventional cooperative transmission.
Declining multi inverter‐based total harmonic distortion with the aid of hybrid optimisation technique
Authors: Vaniyambadi Sathyanarayanan Bharath , Mani Gopinath
Published: September 2014

Multilevel inverter has arrived on the scene as an attractive and unique tool which is extensively employed for adapting dc (direct current) voltage to ac (alternating current) voltage. These appliances have recently taken shape as reliable sources of elevated power and found themselves well‐utilised more often than not in industrial applications, by employing sine or adapted sine waves. The sine wave form generated in the multilevel inverter output has huge harmonics which should be minimised by appropriate steps. With a view to minimise the harmonics at the output signal, it is necessary to cut short the related total harmonic deformation (THD) of switching angles. Genetic algorithm is widely employed for the function of harmonic optimisation. However a hurdle appears as the cost function tends to invite further intricacy for the optimisation, entailing an added number of iterations. Therefore, with an eye on scaling down the number of iterations, the intention of genetic and particle swarm optimisation algorithms is to optimise the switching angles to the utmost. This method also leads to the decline of the related THD values. The innovative method is executed in the MATLAB/Simulink working platform.
System for calibrating the energy-dependent response of an elliptical Bragg-crystal spectrometer
Authors: Marrs R. E. , Brown G. V. , Emig J. A. , Heeter R. F.
Published: September 2014

A multipurpose spectrometer (MSPEC) with elliptical crystals is in routine use to obtain x-ray spectra from laser produced plasmas in the energy range 1.0–9.0 keV. Knowledge of the energy-dependent response of the spectrometer is required for an accurate comparison of the intensities of x-ray lines of different energy. The energy-dependent response of the MSPEC has now been derived from the spectrometer geometry and calibration information on the response of its components, including two different types of detectors. Measurements of the spectrometer response with a laboratory x-ray source are used to test the calculated response and provide information on crystal reflectivity and uniformity.
Role of micro-strain and defects on band-gap, fluorescence in near white light emitting Sr doped ZnO nanorods
Authors: Udayabhaskar R. , Karthikeyan B.
Published: September 2014

We report tunable band gap (red shift in band gap) of ZnO driven by the Sr doping. It is observed that enhanced white light like luminescence from Sr doped ZnO nanorods. Raman studies have carried out to get insight of phonon related vibrational properties. Dopant induced local vibrational mode appeared after Sr incorporation has been identified from Raman studies. Photoluminescence studies show that doped ZnO nanorods fluorescence covers the entire visible region apart from the characteristic exciton related UV luminescence. Crystallite size variation, defects formation, and relaxation of micro strain after doping shows a strong dependence on the luminescence of the prepared samples. The increase in luminescence with increasing dopant concentration is attributed to doping induced changes in crystallinity, micro strain, and defects formation in the samples.
Potential-induced degradation in solar cells: Electronic structure and diffusion mechanism of sodium in stacking faults of silicon
Authors: Ziebarth Benedikt , Mrovec Matous , Elsässer Christian , Gumbsch Peter
Published: September 2014

Sodium decorated stacking faults (SFs) were recently identified as the primary cause of potential-induced degradation in silicon (Si) solar-cells due to local electrical short-circuiting of the p-n junctions. In the present study, we investigate these defects by first principles calculations based on density functional theory in order to elucidate their structural, thermodynamic, and electronic properties. Our calculations show that the presence of sodium (Na) atoms leads to a substantial elongation of the Si-Si bonds across the SF, and the coverage and continuity of the Na layer strongly affect the diffusion behavior of Na within the SF. An analysis of the electronic structure reveals that the presence of Na in the SF gives rise to partially occupied defect levels within the Si band gap that participate in electrical conduction along the SF.
Ferromagnetic resonance micromagnetic studies in patterned permalloy thin films and stripes
Authors: Aranda G. R. , Kakazei G. N. , González J. , Guslienko K. Y.
Published: September 2014

We present micromagnetic simulations of ferromagnetic resonance in patterned permalloy films and isolated stripes. Films of the total thickness 20 nm or 40 nm are patterned in the form of 1D periodic structures with rectangular profile (rectangular grooves of depth varying from zero up to the film thickness) and in-plane period of 500 nm. The direction of the applied dc magnetic field is varied in the film plane from the direction parallel to the stripes to perpendicular one. The thickness of the patterned elements and direction of the bias field affect essentially the resonance peaks (changing their position, amplitude and number) and the corresponding dynamical magnetization profiles. We simulated from one up to three ferromagnetic resonance peaks and found the areas of microwave magnetization localization for them.
Charge-constrained auxiliary-density-matrix methods for the Hartree–Fock exchange contribution
Authors: Merlot Patrick , Izsák Róbert , Borgoo Alex , Kjærgaard Thomas , Helgaker Trygve , Reine Simen
Published: September 2014

Three new variants of the auxiliary-density-matrix method (ADMM) of Guidon, Hutter, and VandeVondele [J. Chem. Theory Comput. 6, 2348 (2010)] are presented with the common feature that they have a simplified constraint compared with the full orthonormality requirement of the earlier ADMM1 method. All ADMM variants are tested for accuracy and performance in all-electron B3LYP calculations with several commonly used basis sets. The effect of the choice of the exchange functional for the ADMM exchange–correction term is also investigated.
Demixing cascades in cluster crystals
Authors: Wilding Nigel B. , Sollich Peter
Published: September 2014

In a cluster crystal, each lattice site is occupied by multiple soft-core particles. As the number density is increased at zero temperature, a “cascade” of isostructural phase transitions can occur between states whose site occupancy differs by unity. For low but finite temperature, each of these transitions terminates in a critical point. Using tailored Monte Carlo simulation techniques, we have studied such demixing cascades in systems of soft particles interacting via potentials of the generalized exponential form u(r) = ε exp [−(r/σ)n]. We have estimated the critical parameters of the first few transitions in the cascade as a function of the softness parameter n. The critical temperature and pressure exhibit non-monotonic behavior as n is varied, although the critical chemical potential remains monotonic. The trends for the pressure and chemical potential are confirmed by cell model calculations at zero temperature. As n → 2+, all the transitions that we have observed are preempted by melting although we cannot rule out that clustering transitions survive at high density.
In situ investigation of explosive crystallization in a-Ge: Experimental determination of the interface response function using dynamic transmission electron microscopy
Authors: Nikolova Liliya , Stern Mark J. , MacLeod Jennifer M. , Reed Bryan W. , Ibrahim Heide , Campbell Geoffrey H. , Rosei Federico , LaGrange Thomas , Siwick Bradley J.
Published: September 2014

The crystallization of amorphous semiconductors is a strongly exothermic process. Once initiated the release of latent heat can be sufficient to drive a self-sustaining crystallization front through the material in a manner that has been described as explosive. Here, we perform a quantitative in situ study of explosive crystallization in amorphous germanium using dynamic transmission electron microscopy. Direct observations of the speed of the explosive crystallization front as it evolves along a laser-imprinted temperature gradient are used to experimentally determine the complete interface response function (i.e., the temperature-dependent front propagation speed) for this process, which reaches a peak of 16 m/s. Fitting to the Frenkel-Wilson kinetic law demonstrates that the diffusivity of the material locally/immediately in advance of the explosive crystallization front is inconsistent with those of a liquid phase. This result suggests a modification to the liquid-mediated mechanism commonly used to describe this process that replaces the phase change at the leading amorphous-liquid interface with a change in bonding character (from covalent to metallic) occurring in the hot amorphous material.
Temperature dependence of the intrinsic and extrinsic contributions in BiFeO3-(K0.5Bi0.5)TiO3-PbTiO3 piezoelectric ceramics
Authors: Bennett J. , Shrout T. R. , Zhang S. J. , Mandal P. , Bell A. J. , Stevenson T. J. , Comyn T. P.
Published: September 2014

This contribution focuses on the use of modified Rayleigh law as a technique for determining the intrinsic and extrinsic (reversible/irreversible) contributions to the piezoelectric effect up to 150 °C across a broad compositional space, augmenting previous understanding of the BiFeO3-(K0.5Bi0.5)TiO3-PbTiO3 system. At room temperature, a mechanistic explanation of the correlation between crystal symmetry, i.e., tetragonal spontaneous strain, xs, and the Rayleigh relations using Landau theory is provided. The intrinsic response was found to be heavily dependent upon the tetragonal xs, whereby an optimisation between polarization and permittivity was elucidated, leading to enhanced piezoelectric charge coefficients. A c/a ratio of ∼1.041 was identified at which the room temperature intrinsic and extrinsic effects were at a maximum; a dinit of 183 × 10−12 m/V and Rayleigh coefficient of 59 × 10−18 m2/V2 were measured, resulting in the largest piezoelectric charge coefficients. The piezoelectric charge coefficient d33, intrinsic and extrinsic contributions of these materials were all found to increase up to 150 °C while adhering to the Rayleigh model. The reversible extrinsic component of the total reversible response, dinit, was calculated to be relatively minor, 4.9% at room temperature, increasing to 12.1% at 150 °C, signifying its increasing influence to the piezoelectric effect, as domain wall motion is thermally activated. Hence, the phenomenological interpretation provided here may be used as a roadmap to elucidate the origins of the temperature dependence of the piezoelectric effect.
Temperature dependent Raman scattering and far-infrared reflectance spectra of MgO modified Pb0.99(Zr0.95Ti0.05)0.98Nb0.02O3 ceramics: A composition effect
Authors: Duan Z. H. , Chang P. , Hu Z. G. , Wang J. X. , Wang G. S. , Dong X. L. , Chu J. H.
Published: September 2014

Lattice dynamics and phase transition of MgO modified Pb0.99(Zr0.95Ti0.05)0.98Nb0.02O3 (PZTN-x wt. % MgO, x = 0, 0.1, 0.2, 0.5) ceramics have been investigated by far-infrared (FIR) reflectance in the temperature range of 5.5–300 K and Raman spectra between 77 and 300 K, respectively. With the aid of above complementary methods, the structure of all ceramics was defined as low-temperature ferroelectric rhombohedral phase [FR(LT)] at room temperature. The FIR dielectric functions were extracted from the multi-Lorentz oscillator dispersion model. The lowest frequency phonon mode, which is related to Pb-BO3 (B = Zr, Ti, Nb) vibration, mainly dominates the FIR dielectric response. With increasing MgO composition, the dielectric constants ε(0) at room temperature are estimated to 85.4, 73.4, 73.9, and 41.9, respectively. The decreasing trend can be due to the doubly ionized oxygen vacancies induced by Mg substitution for B-site. The order-disorder phase transition located around 120 K can be clearly clarified from temperature evolution of phonon frequency, damping, and intensity. It decreases slightly with increasing MgO composition, which influence the distortion due to the broken correlation chains and local permanent dipoles creation. Moreover, the transformation from antiferroelectric orthorhombic AO to [FR(LT)] phase has been observed around 250 K, which is associated with the antiferroelectric displacement of Pb atoms along 〈110〉 and coupled rotations of the corner-connected oxygen octahedral. Furthermore, the transition from [FR(LT)] to [FR(HT)] (high-temperature ferroelectric rhombohedral phase) was identified around 290 K for MgO-doped PZTN ceramics. It arises from the shift of cation (Pb and Zr/Ti/Nb/Mg ions) along the 〈111〉 direction and the transition temperature slightly decreases compared to the pure ceramic.
A closed-form capacitance model for tunnel FETs with explicit surface potential solutions
Authors: Wang Jiaxin , Wu Chunlei , Huang Qianqian , Wang Chao , Huang Ru
Published: September 2014

In this paper, a closed-form physical capacitance model for bulk tunnel FETs (TFETs) is proposed based on the surface potential approach for the first time. Fundamentally different from that in the MOSFET, the channel surface potential φsf in the TFET is alternately controlled by the drain bias and gate bias in different operation regions. On the basis of physical insight into the operation mechanism, the analytical model of φsf as a function of terminal bias is established. The Gaussian box is introduced to predict the surface potential profile near the source-body junction. Furthermore, the surface-potential-based capacitance model is derived and the calculated terminal capacitances show good agreement with the TCAD simulation results. With the essential physics considered, excellent validity of the model is achieved for bulk TFETs with a large range of structure parameters and SOI/double-gate (DG) TFETs.
Ultra-short channel GaN high electron mobility transistor-like Gunn diode with composite contact
Authors: Wang Ying , Yang Lin'an , Wang Zhizhe , Chen Qing , Huang Yonghong , Dai Yang , Chen Haoran , Zhao Hongliang , Hao Yue
Published: September 2014

We present a numerical analysis on an ultra-short channel AlGaN/GaN HEMT-like planar Gunn diode based on the velocity-field dependence of two-dimensional electron gas (2-DEG) channel accounting for the ballistic electron acceleration and the inter-valley transfer. In particular, we propose a Schottky-ohmic composite contact instead of traditional ohmic contact for the Gunn diode in order to significantly suppress the impact ionization at the anode side and shorten the “dead zone” at the cathode side, which is beneficial to the formation and propagation of dipole domain in the ultra-short 2-DEG channel and the promotion of conversion efficiency. The influence of the surface donor-like traps on the electron domain in the 2-DEG channel is also included in the simulation.
Bounds imposed on the sheath velocity of a dense plasma focus by conservation laws and ionization stability condition
Authors: Auluck S. K. H.
Published: September 2014

Experimental data compiled over five decades of dense plasma focus research are consistent with the snowplow model of sheath propagation, based on the hypothetical balance between magnetic pressure driving the plasma into neutral gas ahead and “wind pressure” resisting its motion. The resulting sheath velocity, or the numerically proportional “drive parameter,” is known to be approximately constant for devices optimized for neutron production over 8 decades of capacitor bank energy. This paper shows that the validity of the snowplow hypothesis, with some correction, as well as the non-dependence of sheath velocity on device parameters, have their roots in local conservation laws for mass, momentum, and energy coupled with the ionization stability condition. Both upper and lower bounds on sheath velocity are shown to be related to material constants of the working gas and independent of the device geometry and capacitor bank impedance.
The effects of the chemical composition and strain on the electronic properties of GaSb/InAs core-shell nanowires
Authors: Ning Feng , Wang Dan , Tang Li-Ming , Zhang Yong , Chen Ke-Qiu
Published: September 2014

The effects of the chemical composition and strain on the electronic properties of [111] zinc-blende (ZB) and [0001] wurtzite (WZ) GaSb/InAs core-shell nanowires (NWs) with different core diameters and shell thicknesses are studied using first-principles methods. The band structures of the [111] ZB GaSb/InAs core-shell NWs underwent a noticeable type-I/II band alignment transition, associated with a direct-to-indirect band gap transition under a compressive uniaxial strain. The band structures of the [0001] WZ GaSb/InAs core-shell NWs preserved the direct band gap under either compressive or tensile uniaxial strains. In addition, the band gaps and the effective masses of the carriers could be tuned by their composition. For the core-shell NWs with a fixed GaSb-core size, the band gaps decreased linearly with an increasing InAs-shell thickness, caused by the significant downshift of the conduction bands. For the [111] ZB GaSb/InAs core-shell NWs, the calculated effective masses indicated that the transport properties could be changed from hole-dominated conduction to electron-dominated conduction by changing the InAs-shell thickness.
Contact resistance improvement using interfacial silver nanoparticles in amorphous indium-zinc-oxide thin film transistors
Authors: Xu Rui , He Jian , Song Yang , Li Wei , Zaslavsky A. , Paine D. C.
Published: September 2014

We describe an approach to reduce the contact resistance at compositional conducting/semiconducting indium-zinc-oxide (IZO) homojunctions used for contacts in thin film transistors (TFTs). By introducing silver nanoparticles (Ag NPs) at the homojunction interface between the conducting IZO electrodes and the amorphous IZO channel, we reduce the specific contact resistance, obtained by transmission line model measurements, down to ∼10−2 Ω cm2, ∼3 orders of magnitude lower than either NP-free homojunction contacts or solid Ag metal contacts. The resulting back-gated TFTs with Ag NP contacts exhibit good field effect mobility of ∼27 cm2/V s and an on/off ratio >107. We attribute the improved contact resistance to electric field concentration by the Ag NPs.
Superconductivity in textured Bi clusters/Bi2Te3 films
Authors: Le Phuoc Huu , Tzeng Wen-Yen , Chen Hsueh-Ju , Luo Chih Wei , Lin Jiunn-Yuan , Leu Jihperng
Published: September 2014

We report superconductivity at an onset critical temperature below 3.1 K in topological insulator ∼200-nm-thick Bi2Te3 thin films grown by pulsed laser deposition. Using energy-dispersive X-ray spectroscopy elemental mapping and Auger electron spectroscopy elemental depth profiling, we clearly identified bismuth (Bi) precipitation and Bi cluster signatures. Superconductivity in the Bi2Te3 films was attributed to the proximity effect of Bi clusters precipitated on the surface of the Bi2Te3 films.
Electron-phonon coupling modification and carrier mobility enhancement in poly(3,4-ethylenedioxythiophene) doped with poly(4-styrenesulfonate) films by ultraviolet irradiation
Authors: Lin Yow-Jon , Chin Yi-Min , Wu Cheng-You , Liu Day-Shan
Published: September 2014

The effect of ultraviolet irradiation on the electrical property of poly(3,4-ethylenedioxythiophene) doped with poly(4-styrenesulfonate) (PEDOT:PSS) films was examined. It is shown that the carrier mobility increases while the carrier density does not change substantially. The carrier mobility in PEDOT:PSS samples exhibits strong temperature dependence, indicating the dominance of tunneling (hopping) at low (high) temperatures. The results demonstrate that changes in the chemical structure may lead to the modification of the electron-phonon coupling, thus increasing the carrier mobility in PEDOT:PSS.
Sodium diffusion in 4H-SiC
Authors: Linnarsson M. K. , Hallén A.
Published: September 2014

Sodium diffusion has been studied in p-type 4H-SiC. Heat treatments have been performed from 1200 °C to 1800 °C for 1 min to 4 h. Secondary ion mass spectrometry has been used to measure the sodium distribution. We show that sodium has a considerable mobility at 1200 °C in p-type 4H-SiC. On the other hand for sodium atoms trapped at suitable sites the mobility is limited up to 1800 °C. Trap limited diffusion kinetics is suggested and an effective diffusivity has been extracted with an activation energy of 4 eV for sodium diffusion in p-type 4H-SiC.
Role of Wnt signalling in early pregnancy
Authors: Nayeem Sarmah B. , Arfuso Frank , Dharmarajan Arun , Keelan Jeffrey A.
Published: September 2014

The integration of a complex network of signalling molecules promotes implantation of the blastocyst and development of the placenta. These processes are crucial for a successful pregnancy and fetal growth and development. The signalling network involves both cell–cell and cell–extracellular matrix communication. The family of secreted glycoprotein ligands, the Wnts, plays a major role in regulating a wide range of biological processes, including embryonic development, cell fate, proliferation, migration, stem cell maintenance, tumour suppression, oncogenesis and tissue homeostasis. Recent studies have provided evidence that Wnt signalling pathways play an important role in reproductive tissues and in early pregnancy events. The focus of this review is to summarise our present knowledge of expression, regulation and function of the Wnt signalling pathways in early pregnancy events of human and other model systems, and its association with pathological conditions. Despite our recent progress, much remains to be learned about Wnt signalling in human reproduction. The advancement of knowledge in this area has applications in the reduction of infertility and the incidence and morbidity of gestational diseases.
Como dicen los americanos
Authors: Sanz-Sánchez Israel
Published: September 2014

This study analyzes the patterns of incorporation of English elements in New Mexican Spanish in the decades following the annexation of New Mexico by the United States as reflected in a corpus of private letters written between 1848 and 1936. The quantitative analysis shows that most types of contact features are infrequent during much of this period, but there is an increase in the presence of English elements in the last decades covered by the corpus. It also shows that semantic and lexical borrowing is much more frequent than structural interference or code-switching. These findings are then correlated with the general sociolinguistic environment of post-annexation Hispanic New Mexico, where bilingualism and language shift to English were much more infrequent than elsewhere in the US Southwest. Attention is also paid to features that pertain exclusively to the written language, and their distribution is explained as a function of the degree of exposure of Hispanic New Mexicans to literacy in English and Spanish.
Fruit ripening: physiology, signalling, genomics.
Authors: Pravendra Nath Pravendra Nath , Pech J. C.
Published: September 2014

Fruits are important to our dietary requirements as they provide vitamins, minerals, antioxidant and various other molecules important to human health. Ethylene plays a major role in fruit development and ripening. During ripening, various physiological and biochemical changes take place through recruitment of thousands of genes that result in development of colour, taste and flavour. Studies on ethylene signalling has enabled in the identification of various regulators of ripening including ethylene response factors, which are the final player in controlling expression of ethylene responsive (target) genes. Recent developments in Omic approaches such as transcriptomic, genomic, mRNAs sequences, chromatin immune-precipitation, etc. have helped in identifying several target genes, including transcriptional regulators that affect ripening-related changes. The pair identification of microRNA and their target mRNAs as well as the discovery of DNA hypermethylation during fruit ripening open new perspectives in the post-transcriptional and epigenetic regulation of the ripening process. The availability of the genome sequences of many fruit species is fostering the identification of molecular markers and novel regulators of the ripening process.
The practical implementation of microalgal biodiesel: challenges and potential solutions.
Authors: Sen Gupta S. , Sharad Bhartiya Sharad Bhartiya , Yogendra Shastri Yogendra Shastri
Published: September 2014

With conventional fossil energy reserves diminishing as well as atmospheric pollution increasing through excessive use of these resources, we need to switch to cleaner, renewable replacement sources of energy for a sustainable future. Bioenergy is a promising alternative among the different renewable energy sources, and microalgae in particular are of interest because of their various desirable properties. Microalgae can yield a very high lipid content, which can be processed to biodiesel. They can capture carbon dioxide and can be grown even on degraded land with waste water. Additionally, it is possible to generate a variety of products such as ethanol, biogas and pharmaceuticals from microalgae. Inspite of these promising attributes, its commercial scale implementation has been limited. Here, the major challenge is the relatively high cost associated with the entire process. Additionally, each of the processing steps exhibits several technological challenges. This paper reviews the details of each processing step to produce biodiesel from microalgae, with the emphasis on the different challenges, bottlenecks and technological barriers, as well as possible solutions to them. Various other potential uses of microalgae are also briefly discussed. The focus of this review article is on the underlying differences between theoretical and practical potential of an integrated microalgal biorefinery.
Prion disease zoonosis: assessing risk associated with new and emerging prion agents.
Authors: Barron R. M.
Published: September 2014

Prion diseases are infectious neurodegenerative diseases associated with the misfolding, aggregation and deposition of host prion protein (PrP) in the brain. These diseases include scrapie in sheep, bovine spongiform encephalopathy (BSE) in cattle, chronic wasting disease (CWD) in deer and Creutzfeldt-Jakob disease (CJD) in humans. The infectious agent is thought to be composed solely of a misfolded form of PrP (PrP
Sc
) that propagates by binding and converting host PrP into the abnormal conformation. Natural routes of transmission appear to be oral, but the disease can also be spread by intravenous, intracerebral or peripheral exposure. Human prion diseases, such as CJD, were generally considered to have a spontaneous or familial (linked to mutations in the PrP gene) aetiology, although subsequent iatrogenic transmission has been demonstrated in some cases. Risks posed to humans from prion diseases in animals were therefore thought to be low. The emergence of BSE in the UK was followed by the appearance of a new variant of human prion disease (vCJD), and transmission studies in rodents confirmed that the two diseases were caused by the same strain of the prion agent. These data proved that some ruminant prion diseases could be zoonotic, and a potential risk to humans may exist from new and emerging prion agents in ruminants. Indeed analysis and characterization of recently identified prion isolates in ruminants (atypical scrapie, H-type BSE, L-type BSE and CWD) has revealed that some may pose a risk of transmission to humans, and are still a concern to public health.
Distorted representations of the ‘capability approach’ in Australian school education
Authors: Skourdoumbis Andrew
Published: September 2014

Recently, curriculum developments in Australia have seen the incorporation of functionalist ‘general capabilities’ as essential markers of schooling, meaning that any pedagogical expression of classroom‐based practice, including subsequent instruction, should entail the identification and development of operational general capabilities. The paper questions and critiques recent curriculum developments in Australia that characterises capabilities purely in functionalist terms, something that the broader capabilities literature eschews. The analysis is informed by aspects of the theoretical frameworks of Martin Heidegger and Pierre Bourdieu. It examines the notion of ‘general capabilities’ in the Australian Curriculum. The paper argues that there is an inherent contradiction in Australian education policy, namely a vocationally oriented national school curriculum with implied functionings that cannot fulfil designated purposes. The paper finds that the curriculum%s connection to increased individual and national economic prosperity, one championing ‘jobs and careers of the twenty‐first century’, is evident, although current populous forms and categories of employment seem to suggest otherwise.
The effect of resisted sprint training on maximum sprint kinetics and kinematics in youth
Authors: Rumpf Michael C. , Cronin John B. , Mohamad Ikhwan N. , Mohamad Sharil , Oliver Jon L. , Hughes Michael G.
Published: September 2014

Resisted sled towing is a popular and efficient training method to improve sprint performance in adults, however, has not been utilised in youth populations. The purpose therefore was to investigate the effect of resisted sled towing training on the kinematics and kinetics of maximal sprint velocity in youth of different maturation status. Pre‐ and post‐intervention 30 metre sprint performance of 32 children, 18 pre‐peak height velocity (PHV) and 14 mid‐/post‐PHV, were tested on a non‐motorised treadmill. The 6‐week intervention consisted of ∼12 sessions for pre‐PHV and 14 for mid‐/post‐PHV of resisted sled towing training with each sessions comprised of 8–10 sprints covering 15–30 metres with a load of 2.5, 5, 7.5 or 10% body mass. Pre‐PHV participants did not improve sprint performance, while the mid‐/post‐PHV participants had significant (P < 0.05) reductions (percent change, effect size) in sprint time (−5.76, −0.74), relative leg stiffness (−45.0, −2.16) and relative vertical stiffness (−17.4, −0.76) and a significant increase in average velocity (5.99, 0.76), average step rate (5.65, 0.53), average power (6.36, 0.31), peak horizontal force (9.70, 0.72), average relative vertical forces (3.45, 1.70) and vertical displacement (14.6, 1.46). It seems that sled towing may be a more suitable training method in mid‐/post‐PHV athletes to improve 30 metre sprint performance.
Elite athletes' attitudes towards the use of placebo‐induced performance enhancement in sports
Authors: Bérdi Márk , Köteles Ferenc , Hevesi Krisztina , Bárdos György , Szabo Attila
Published: September 2014

While an increasing number of research is devoted to the understanding of placebo effects in sports, athletes' experiences with and attitudes towards the use of placebo for performance enhancement remain poorly understood. In this study, 79 elite athletes from different sports were surveyed on five issues related to placebo use in sports. Results showed that 47% of the athletes have experienced placebo effects in the past. A majority of the athletes (82%) thought that placebos could affect their sports performances. A wider use of placebos in sport settings was endorsed more by those who have experienced placebo effects in the past than those who did not (P =. 005). Regardless of past experience with placebo, more than half of the athletes (53%) would accept an unknown but legitimate substance from the coach, and 67% of them would not mind a placebo‐linked deception if that was effective. These findings confirm that most elite athletes believe in the power of placebos in enhancing sports performance, and those having a positive past experience exhibit slightly more favourable attitudes in contrast to those without such experiences.
An explicit formula for the cubic Szegő equation
Authors: Gérard Patrick , Grellier Sandrine
Published: September 2014

We derive an explicit formula for the general solution of the cubic Szegő equation and of the evolution equation of the corresponding hierarchy. As an application, we prove that all the solutions corresponding to finite rank Hankel operators are quasiperiodic.
Insights into structural variations and genome rearrangements in prokaryotic genomes
Authors: Periwal Vinita , Scaria Vinod
Published: September 2014

Structural variations (SVs) are genomic rearrangements that affect fairly large fragments of DNA. Most of the SVs such as inversions, deletions and translocations have been largely studied in context of genetic diseases in eukaryotes. However, recent studies demonstrate that genome rearrangements can also have profound impact on prokaryotic genomes, leading to altered cell phenotype. In contrast to single-nucleotide variations, SVs provide a much deeper insight into organization of bacterial genomes at a much better resolution. SVs can confer change in gene copy number, creation of new genes, altered gene expression and many other functional consequences. High-throughput technologies have now made it possible to explore SVs at a much refined resolution in bacterial genomes. Through this review, we aim to highlight the importance of the less explored field of SVs in prokaryotic genomes and their impact. We also discuss its potential applicability in the emerging fields of synthetic biology and genome engineering where targeted SVs could serve to create sophisticated and accurate genome editing.

Contact:  vinods@igib.in

Supplementary information:  Supplementary data are available at Bioinformatics online.
Evolutionary and ecological constraints of fish spawning habitats
Authors: Ciannelli Lorenzo , Bailey Kevin , Olsen Esben Moland
Published: September 2014

For marine fish, the choice of the spawning location may be the only means to fulfil the dual needs of surviving from the egg to juvenile stage and dispersing across different habitats while minimizing predation and maximizing food intake. In this article, we review the factors that affect the choice of fish spawning habitats and propose a framework to distinguish between ecological and evolutionary constraints. We define the former as the boundaries for phenotypically plastic responses to environmental change, in this case the ability of specific genotypes to change their spawning habitat. Processes such as predation, starvation, or aberrant dispersal typically limit the amount of variability in spawning habitat that fish may undergo from 1 year to the next, and thus regulate the intensity of ecological constraints. Evolutionary constraints, on the other hand, refer to aspects of the genetic make-up that limit the rate and direction of adaptive genetic changes in a population across generations; that is, the potential for micro-evolutionary change. Thus, their intensity is inversely related to the level of genetic diversity associated with traits that regulate spawning and developmental phases. We argue that fisheries oceanographers are well aware of, and more deeply focused on, the former set of constraints, while evolutionary biologists are more deeply focused on the latter set of constraints. Our proposed framework merges these two viewpoints and provides new insight to study fish habitat selection and adaptability to environmental changes.
The Dialectic of Pro-Poor Papaya
Authors: Lynas Mark , Davidson Evanega Sarah
Published: September 2014

The development and rapid adoption of genetically engineered, virus-resistant papaya for Hawaii was an early, rare successful case of a small-scale horticultural crop improved for farmers of mostly modest means by the public sector. Demand was potentially great because the technology addressed a crop-destroying disease for which there were—and are—no alternative solutions. The developers of the technology promoted diffusion with a philanthropic spirit of public-sector universities and personal commitment. Success in Hawaii demonstrated that the technology could benefit papaya growers world-wide. To replicate that success, Thailand was among the first countries to work to adapt the technology. The greatest challenge facing those charged with introducing virus-resistant transgenic papaya into Thailand turned out not to be a technical but political one as Greenpeace targeted virus-resistant papaya as the likely first GE crop to be grown in the country and thus, a gateway for other GE crops. The subsequent anti-GE papaya campaigns foiled biotechnology in Thailand and throughout Southeast Asia, which is puzzling because many biotech crops being developed in that region have similar potential to benefit smallholder farmers, impact the environment positively, and address major nutritional challenges. Many are developed by the public sector. Had Thailand successfully promoted transgenic papaya despite opposition from Greenpeace, governments and scientific agencies across Southeast Asia might have been encouraged by the success story and continued to use the tools of biotechnology in their own agricultural sectors to confront rapidly mounting global agricultural challenges. That this best-case scenario for biotechnology—a pro-poor papaya developed in the public sector without multinational property claims—has not reached resource-poor farmers in the developing world almost twenty years after its release in Hawaii offers lessons larger than a minor crop. The case aids in understanding the reasons for the limited spread of biotechnology for small farmers globally and the dimensions of opposition and reasons for success of opposition to all transgenics technologies.
How “The Gossip” Became a Woman and How “Gossip” Became Her Weapon of Choice
Authors: McAndrew Francis T.
Published: September 2014

Gossip is the weapon of choice in the indirect relationship aggression that occurs among women. However, gossip can also be a positive force in the life of groups. In this chapter, I maintain that gossip is an evolutionary adaptation that enabled our prehistoric ancestors to be socially successful and explore the complicated roles gossip plays in human social life. I argue that an interest in the affairs of same-sex others is especially strong among females and that this is not always benign. I review the evidence that women are more likely than men to use gossip in an aggressive, competitive manner and maintain that understanding the dynamics of competitive gossip may also give us insight into related social phenomena such as how people use social media such as Facebook and why men and women often have such different tastes in movies and television.
Structuralism and its Archaeological Legacy
Authors: Preucel Robert
Published: September 2014

Structuralism is an important influence in the development of Anglo-American archaeology. Its basic insight is to conceptualize the world in terms of relationships between things rather than in terms of the things themselves. Alongside functionalism and adaptationalism, it played a seminal role in the early days of processual archaeology, particularly in the context of systems theory. Structuralism and its poststructural critiques were also central to the rise of postprocessual approaches and their engagement with issues of reading, writing, discourse and performance. While structuralism is no longer advocated in its original forms, its legacies are evident in many current research directions. Among these directions are cognitive archaeology, Peircian semiotics, and network analysis.
Organic Imperialism
Authors: Kucich John
Published: September 2014

Empire studies has largely overcome tendencies to view metropole and periphery as oppositional. Nevertheless, critics’ focus on sexual and racial forms of reciprocal cultural constitution has eclipsed analysis of how competing conceptions of social order interrogated each another at sites of cross-cultural exchange. What has chiefly escaped revision is the notion that the empire was based on an organic social model that remained fundamentally conservative despite cross-cultural contacts. In nineteenth-century Britain, organicism acquired elasticity as new forms of social mobility and inclusiveness pervaded domestic life. In the colonial context, these progressive conceptions of organicism were sometimes transformed by encounters with indigenous societies. The central argument of this essay is that nineteenth-century organic imperialism was increasingly liberalized, and was further modified by fictional representations of non-Western social order. It focuses on sea adventure fiction and two colonial novels: Joseph Conrad’s Lord Jim (1899) and Rudyard Kipling’s Kim (1901).