bluuebunny/crossref_metadata_2025 huggingface dataset:
Small fiber neuropathy: Getting bigger!
Authors: Chan Amanda C.Y. , Wilder‐Smith Einar P.
Published: February 2016

Etiological and clinical heterogeneity of small fiber neuropathy (SFN) precludes a unifying approach and necessitates reliance on recognizable clinical syndromes. Symptoms of SFN arise from dysfunction in nociception, temperature, and autonomic modalities. This review focuses on SFN involving nociception and temperature, examining epidemiology, etiology, clinical presentation, diagnosis, pathophysiology, and management. Prevalence of SFN is 52.95 per 100,000 population, and diabetes and idiopathic are the most common etiologies. Dysesthesia, allodynia, pain, burning, and coldness sensations frequently present in a length‐dependent pattern. Additional autonomic features in gastrointestinal, urinary, or cardiovascular systems are frequent but poorly objectified. SFN is diagnosed by intraepidermal nerve fiber density and quantitative sensory and autonomic tests in combination with normal nerve conduction. Pathophysiological understanding centers on sodium channel dysfunction, and genetic forms are beginning to be understood. Treatment is directed at the underlying etiology supported by symptomatic treatment using antidepressants and anticonvulsants. Little is known about long‐term outcomes, and systematic cohort studies are needed. Muscle Nerve 53: 671–682, 2016
Impact and flexural properties of PP/CaSiO3 composites
Authors: Liang Ji‐Zhao
Published: February 2016

The effects of filler surface treatment and content on the impact fracture toughness and flexural properties of polypropylene (PP) composites filled with wollastonite (CaSiO3) were investigated. The results showed that the introduction of the filler could toughen and reinforce the PP; the influences of the filler surface treatment on the toughness and strength were significant; the values of the Izod V‐notched impact strength and the Charpy V‐notched impact strength of the composites increased with increasing the filler weight fractions; the values of flexural modulus increased with increasing the filler weight fractions; the flexural strength increased when the filler weight fraction was lower than 10% and then varied slightly. This toughening effect should be attributed to the stress concentration because of strip shape of the filler and to block the development of the notched cracks in the matrix, improving the notched sensitivity to the impact fracture of the PP composites. This study should be helpful to understand the mechanisms of CaSiO3 reinforcing and toughening PP resin. POLYM. COMPOS., 39:398–404, 2018. © 2016 Society of Plastics Engineers
Key players in neurodegenerative disorders in focus—New insights into the proteomic profile of Alzheimer's disease, schizophrenia, ALS, and multiple sclerosis—24th HUPO BPP Workshop
Authors: Schrötter Andreas , Park Young Mok , Marcus Katrin , Martins‐de‐Souza Daniel , Nilsson Peter , Magraoui Fouzi El , Meyer Helmut E. , Grinberg Lea T.
Published: February 2016

The HUPO Brain Proteome Project (HUPO BPP) held its 24th workshop in Vancouver, Canada, September 29, 2015. The focus of the autumn workshop was on new insights into the proteomic profile of Alzheimer's disease, schizophrenia, ALS and multiple sclerosis.
Function changing mutations in glucocorticoid receptor evolution correlate with their relevance to mode coupling
Authors: Kav Batuhan , Öztürk Murat , Kabakçιoğlu Alkan
Published: February 2016

Nonlinear effects in protein dynamics are expected to play role in function, particularly of allosteric nature, by facilitating energy transfer between vibrational modes. A recently proposed method focusing on the non‐Gaussian shape of the configurational population near equilibrium projects this information onto real space in order to identify the aminoacids relevant to function. We here apply this method to three ancestral proteins in glucocorticoid receptor (GR) family and show that the mutations that restrict functional activity during GR evolution correlate significantly with locations that are highlighted by the nonlinear contribution to the near‐native configurational distribution. Our findings demonstrate that the analysis of nonlinear effects in protein dynamics can be harnessed into a predictive tool for functional site determination. Proteins 2016; 84:655–665. © 2016 Wiley Periodicals, Inc.
Crystal structure of the deglycating enzyme Amadoriase I in its free form and substrate‐bound complex
Authors: Rigoldi Federica , Gautieri Alfonso , Dalle Vedove Andrea , Lucarelli Anna Paola , Vesentini Simone , Parisini Emilio
Published: February 2016

Amadoriases, also known as fructosyl amine oxidases (FAOX), are enzymes that catalyze the de‐glycosylation of fructosyl amino acids. As such, they are excellent candidates for the development of enzyme‐based diagnostic and therapeutic tools against age‐ and diabetes‐induced protein glycation. However, mostly because of the lack of a complete structural characterization of the different members of the family, the molecular bases of their substrate specificity have yet to be fully understood. The high resolution crystal structures of the free and the substrate‐bound form of Amadoriase I shown herein allow for the identification of key structural features that account for the diverse substrate specificity shown by this class of enzymes. This is of particular importance in the context of the rather limited and partially incomplete structural information that has so far been available in the literature on the members of the FAOX family. Moreover, using molecular dynamics simulations, we describe the tunnel conformation and the free energy profile experienced by the ligand in going from bulk water to the catalytic cavity, showing the presence of four gating helices/loops, followed by an “L‐shaped” narrow cavity. In summary, the tridimensional architecture of Amadoriase I presented herein provides a reference structural framework for the design of novel enzymes for diabetes monitoring and protein deglycation. Proteins 2016; 84:744–758. © 2016 Wiley Periodicals, Inc.
Public‐key encryption with keyword search secure against continual memory attacks
Authors: Hu Chengyu , Yang Rupeng , Liu Pengtao , Yu Zuoxia , Zhou Yongbin , Xu Qiuliang
Published: February 2016

Continual memory attacks, inspired by recent realistic physical attacks, have broken many cryptographic schemes that were considered secure in traditional cryptography model. In this paper, we consider the continual memory leakage resilience in public‐key encryption with keyword search scheme (PEKS). We give the definition of continual memory leakage resilience security for PEKS, which allows continual secret key leakage in the trapdoor generation algorithm rather than leakage of trapdoor itself. We believe that the definition is more suitable for practical PEKS scenario. To construct a concrete PEKS scheme secure against continual memory attacks, we firstly obtain a continual master‐key leakage‐resilient anonymous identity‐based encryption (IBE) scheme by applying the generic tool provided by Lewko et al. to a fully secure anonymous IBE scheme that comes from the fully secure anonymous hierarchical identity‐based encryption (HIBE) scheme of De Caro and colleagues. Then, we transform our continual master‐key leakage‐resilient anonymous IBE scheme to a PEKS scheme using the generic Anonymous IBE‐to‐PEKS transformation and prove its continual leakage‐resilient security. Copyright © 2016 John Wiley & Sons, Ltd.
Reliably detecting snowshoe hares with winter track counts
Authors: Burt David M. , Roloff Gary J. , Etter Dwayne R. , Clark Eric
Published: February 2016

We determined the optimum transect length and spacing for detecting snowshoe hare (Lepus americanus) from snow‐track surveys in a fixed area. We also evaluated the utility of the most reliable and efficient designs for indexing hare density. We constructed enclosures (∼6.1 ha) at 2 locations in the Upper Peninsula of Michigan, USA, and populated the enclosures with radiocollared hares. Hare densities ranged from 0.2 to 1.5 hares/ha in the enclosures, comparable to low and high densities recorded at the southern extent of snowshoe hare range. During winters of 2012–2014, we conducted snow‐track surveys along 9 transects spaced 25 m apart in the enclosures 12–65 hr after a snowfall and mapped the location of every track that intersected a transect. After standardizing the track maps by time since last snowfall, we simulated different transect lengths and spacing and evaluated whether hares were documented on the resultant transect segments. We deemed transect configurations reliable if >90% of the 10,000 simulations correctly denoted the site as occupied. Of the 28 possible transect configurations, only 10 combinations were found to reliably detect hares. We refined the 10 reliable configurations based on efficiency, where efficiency was based on the distance traversed by a surveyor. We recommend using transects that are 150 m in length with 100‐m or 75‐m spacing, or 125 m in length with 75‐m spacing to reliably and efficiently survey a fixed area for snowshoe hares. © 2016 The Wildlife Society.
Identification and evaluation of intervarietal substitution lines of rapeseed (Brassica napus L.) with donor segments affecting the diploidization rate of isolated microspores
Authors: Kampouridis Anthimos , Ziese-Kubon Katharina , Nurhasanah  , Ecke Wolfgang
Published: February 2016

InBrassicaspecies microspore derived doubled haploid lines are an important tool in breeding and research. A limiting step in the production of doubled haploid lines is the diploidization of the microspores. Strong differences have been observed in diploidization rates between different genotypes but little is know about the genetic control of these differences. To identify genomic regions that carry genetic factors controlling the diploidization rate of isolated microspores of rapeseed, marker segregations were compared between segregating populations of diploid and haploid microspore derived embryos and a BC1from a cross between ‘Express 617’ and ‘RS239’. After map construction ten intervarietal substitution lines from the same cross were selected with donor segments covering five genomic regions that showed a pattern of skewed marker segregations across the three populations indicative of the segregation of genes controlling the diploidization rates. The diploidization rates of microspores of the ten lines ranged from 23.9 to 58.7 % while the recurrent parent ‘Express 617’ showed a rate of 52.5 %. For three lines the diploidization rates were significantly lower (P = 0.05) than the rate of ‘Express 617’. By comparing donor segments between the significant and the non-significant lines, seven genomic regions that cover just between 4.17 and 6.16 % of the rapeseed genome were identified that may contain genetic factors controlling diploidization rates in rapeseed. In addition, one marker was found that has a high probability to be linked to such a factor. The significant lines represent an ideal material for further in depth studies of this trait.
Patterns of an elevational gradient affecting moths across the South Korean mountains: effects of geometric constraints, plants, and climate
Authors: Choi Sei‐Woong
Published: February 2016

We investigated elevational richness patterns of three moth groups (Erebidae, Geometridae, and Noctuidae) along four elevational gradients located on one northern and three southern mountains in South Korea, as well as the effects of plants and climatic factors on the diversity patterns of moths. Moths were collected with an ultraviolet light trap at 32 sites from May through October, 2013. Plant species richness and mean temperatures for January and June were acquired. Observed and estimated moth species richness was calculated and the diversity patterns with null models were compared. Species richness along four elevational gradients peaked at mid‐elevations, whereas deviations occurred at elevations below mid‐peak in the southern mountains and elevations higher than mid‐peak on the northern mountain. Species richness curves of three moth groups also peaked at mid‐elevations throughout South Korea. However, the species richness curves for Erebidae were positively skewed, indicating that a preference for lowlands, whereas curves of the Geometridae were negatively skewed, indicating a preference for highlands. The mid‐peak diversity pattern between plants and moths on the Korean mountains showed an elevational breadth that overlapped between 800 and 900 m. Multiple regression analysis revealed that plant species richness and January mean temperature significantly influenced moth species richness and abundance. The rapid increase in mean annual temperature in the Korean peninsula and the unimodal elevational gradients of moths across the country suggest that an uphill shift in peak optimum elevation and changes in the highest peak of the curve will occur in the future.
Perfectly Wetting Mixtures of Surfactants from Renewable Resources: The Interaction and Synergistic Effects on Adsorption and Micellization
Authors: Szumała Patrycja , Mówińska Alicja
Published: February 2016

This paper presents a study of the surface properties of mixtures of surfactants originating from renewable sources, i.e., alkylpolyglucoside (APG), ethoxylated fatty alcohol (AE), and sodium soap (Na soap). The main objective was to optimize the surfactant ratio which produces the highest wetting properties during the analysis of the solution of the individual surfactants, two‐ and three‐component mixtures, and at different pH values. The results showed the existence of a synergistic effect in lowering the interfacial tension, critical micelle concentration and the formation of mixed micelles in selected solutions. We found that best wetting properties were measured for the binary AE:APG mixtures. It has been demonstrated that slightly lower contact angles values were observed on Teflon and glass surfaces for the AE:APG:soap mixtures but the results were obtained for higher concentration of the components. In addition, all studied solutions have very good surface properties in acidic, basic and neural media. However, the AE:soap (molar ratio of 1:2), AE:APG (2:1) and AE:APG:soap (1:1:1) compositions improved their wetting power at pH 7 on the aluminium and glass surfaces, as compared to solutions at other pH values tested (selected Θ values close to zero—perfectly wetting liquids). All described effects detected would allow less surfactant to be used to achieve the maximum capacity of washing, wetting or solubilizing while minimizing costs and demonstrating environmental care.
Uterine anatomy and function on cine magnetic resonance imaging
Authors: Kido Aki , Togashi Kaori
Published: February 2016

The female reproductive organ undergoes dynamic morphological changes under the influence of hormonal stimuli, and particularly those mediated by estrogen and progesterone. The uterus changes both its morphological appearance and its functional movements in function of these influences. Functionally, the uterus is known to exert two kinds of inherent contractility: sustained uterine contractions and uterine peristalsis. The former is focal and consists of the sporadic bulging of the myometrium, while the latter is rhythmic and manifests itself as the subtle stripping movement in the subendometrial myometrium. The mechanisms underlying these uterine movements, their relationship and their correlation to age, pharmaceutical administration, and a variety of gynecologic and obstetrical problems remain under discussion. Cine MR imaging may offer the potential to directly observe the changes undergone by the uterus in relation to important functions such as fertility and menstrual problems.
Mutual long‐term effects of school bullying, victimization, and justice sensitivity in adolescents
Authors: Bondü Rebecca , Rothmund Tobias , Gollwitzer Mario
Published: February 2016

In the present study, we investigate long‐term relations between experiences of aggression at school and the development of justice sensitivity as a personality disposition in adolescents. We assessed justice sensitivity (from the victim, observer, and perpetrator perspective), bullying, and victimization among 565 German 12‐ to 18‐year‐olds in a one‐year longitudinal study with two measurement points. Latent path analyses revealed gender differences in long‐term effects of bullying and victimization on observer sensitivity and victim sensitivity. Experiences of victimization at T1 predicted an increase in victim sensitivity among girls and a decrease in victim sensitivity among boys. Bullying behavior at T1 predicted an increase in victim sensitivity among boys and a decrease in observer sensitivity among girls. We did not find long‐term effects of justice sensitivity on bullying and victimization. Our findings indicate that experiences of bullying and victimization have gender‐specific influences on the development of moral personality dispositions in adolescents.
Single-Cell Transcriptome Study as Big Data
Authors: Yu Pingjian , Lin Wei
Published: February 2016

The rapid growth of single-cell RNA-seq studies (scRNA-seq) demands efficient data storage, processing, and analysis. Big-data technology provides a framework that facilitates the comprehensive discovery of biological signals from inter-institutional scRNA-seq datasets. The strategies to solve the stochastic and heterogeneous single-cell transcriptome signal are discussed in this article. After extensively reviewing the available big-data applications of next-generation sequencing (NGS)-based studies, we propose a workflow that accounts for the unique characteristics of scRNA-seq data and primary objectives of single-cell studies.
Mexico's University Network of Atmospheric Observatories
Authors: Peralta O. , Adams D. , Castro T. , Grutter M. , Varela A.
Published: February 2016

Increasing cooperation in Mexico benefits climatologists, meteorologists, and science as a whole.
Distant Rains Contributed to La Niña Ocean Warming Event
Authors: Stanley Sarah
Published: February 2016

Unusually low salinity intensified a warm-water current off the coast of Western Australia in 2010–2011.
Magnetic Field Pulsations and Aurora Tightly Linked
Authors: Zastrow Mark
Published: February 2016

Mysterious plasma waves from space are generating displays of aurora near Earth's poles.
Scientists Denounce Pending Australian Climate Science Cuts
Authors: Kollipara Puneet
Published: February 2016

The recently unveiled planned shift from basic climate research toward responses to a transformed climate could cost research jobs, hamper climate studies, and limit data gathering and analysis.
Backbone cup – a structure design competition based on topology optimization and 3D printing
Authors: Zhu Ji-Hong , Yang Kai-Ke , Zhang Wei-Hong
Published: February 2016

This paper addresses a structure design competition based on topology optimization and 3D Printing, and proposes an experimental approach to efficiently and quickly measure the mechanical performance of the structures designed using topology optimization. Since the topology optimized structure designs are prone to be geometrically complex, it is extremely inconvenient to fabricate these designs with traditional machining. In this study, we not only fabricated the topology optimized structure designs using one kind of 3D Printing technology known as stereolithography (SLA), but also tested the mechanical performance of the produced prototype parts. The finite element method is used to analyze the structure responses, and the consistent results of the numerical simulations and structure experiments prove the validity of this new structure testing approach. This new approach will not only provide a rapid access to topology optimized structure designs verifying, but also cut the turnaround time of structure design significantly.
Pathological scattering by a defect in a slow-light periodic layered medium
Authors: Shipman Stephen P. , Welters Aaron T.
Published: February 2016

Scattering of electromagnetic fields by a defect layer embedded in a slow-light periodically layered ambient medium exhibits phenomena markedly different from typical scattering problems. In a slow-light periodic medium, constructed by Figotin and Vitebskiy, the energy velocity of a propagating mode in one direction slows to zero, creating a “frozen mode” at a single frequency within a pass band, where the dispersion relation possesses a flat inflection point. The slow-light regime is characterized by a 3 × 3 Jordan block of the log of the 4 × 4 monodromy matrix for EM fields in a periodic medium at special frequency and parallel wavevector. The scattering problem breaks down as the 2D rightward and leftward mode spaces intersect in the frozen mode and therefore span only a 3D subspace V˚ of the 4D space of EM fields. Analysis of pathological scattering near the slow-light frequency and wavevector is based on the interaction between the flux-unitary transfer matrix T across the defect layer and the projections to the rightward and leftward spaces, which blow up as Laurent-Puiseux series. Two distinct cases emerge: the generic, non-resonant case when T does not map V˚ to itself and the quadratically growing mode is excited and the resonant case, when V˚ is invariant under T and a guided frozen mode is resonantly excited.
Sub-micron solid air tracers for quantum vortices and liquid helium flows
Authors: Fonda Enrico , Sreenivasan Katepalli R. , Lathrop Daniel P.
Published: February 2016

The dynamics of quantized vortices in superfluids has received increased attention recently because of novel techniques developed to visualize them directly. One of these techniques [G. P. Bewley et al., Nature 441, 588 (2006)] visualized quantized vortices and their reconnections in superfluid flows of 4He by using solid hydrogen tracers of micron-size or larger. The present work improves upon the previous technique by using substantially smaller particles created by injecting atmospheric air diluted in helium gas. These smaller particles are detectable thanks to the higher index of refraction of nitrogen compared to hydrogen and thanks to an improved visualization setup. The optical counting estimate, which agrees with terminal velocity estimates, suggests that the tracer diameter is typically 400 ± 200 nm and could be as small as 200 nm; being smaller, but not so small as to be influenced by thermal motion, the particles get trapped on the vortices faster, perturb the vortices less, possess smaller Stokes drag, and stay trapped on fast-moving vortices, as also on vortices generated closer to the superfluid transition temperature. Unlike the past, the ability to create particles in the superfluid state directly (instead of creating them above the λ-point and cooling the fluid subsequently), ensures greater temperature stability for longer periods, and enables the tracking of long and isolated vortices. These advantages have also led to the direct visualization of Kelvin waves. The use of other seed gases could lead to the visualization of even smaller tracers for quantized vortices. We discuss the visualization setup and provide suggestions for further improvement.
The Jahn-Teller plus pseudo-Jahn-Teller vibronic problem in the C3 radical and its topological implications
Authors: Rocha C. M. R. , Varandas A. J. C.
Published: February 2016

The combined Jahn-Teller plus pseudo-Jahn-Teller [(E′+A1′)⊗e′] problem is discussed for the tricarbon radical (C3) by means of ab initio calculations at the multireference configuration interaction level of theory. For the 1E′ electronic state arising from a e′2 valence configuration, three additional symmetry-equivalent C2v seams are found to lie in close proximity to the D3h symmetry-required seam over the entire range of the breathing coordinate here considered. As the perimeter of the molecule increases, the C2v disjoint seams approach the D3h one almost linearly and ultimately coalesce with it at Q1 = 5.005 a0, thence forming an intersection node or confluence. By further increasing the size of the molecular triangle, the C2v seams get rotated by ±π in the g-h plane. A three-state vibronic Hamiltonian is also proposed to model locally the title system and shown to accurately mimic the calculated data over the region close to the minimum energy crossing point. No net geometric phase effect is observed when the associated electronic wave functions are adiabatically transported along closed paths encircling the four singularity points. For all paths enclosing the intersection node, the sign reversal criterion is shown to be not fulfilled, even for infinitesimal loops. The results so obtained are expected to be valid for other ring systems experiencing similar topological attributes.
Nano-textured copper oxide nanofibers for efficient air cooling
Authors: An Seongpil , Jo Hong Seok , Al-Deyab Salem S. , Yarin Alexander L. , Yoon Sam S.
Published: February 2016

Ever decreasing of microelectronics devices is challenged by overheating and demands an increase in heat removal rate. Herein, we fabricated highly efficient heat-removal coatings comprised of copper oxide-plated polymer nanofiber layers (thorny devil nanofibers) with high surface-to-volume ratio, which facilitate heat removal from the underlying hot surfaces. The electroplating time and voltage were optimized to form fiber layers with maximal heat removal rate. The copper oxide nanofibers with the thorny devil morphology yielded a superior cooling rate compared to the pure copper nanofibers with the smooth surface morphology. This superior cooling performance is attributed to the enhanced surface area of the thorny devil nanofibers. These nanofibers were characterized with scanning electron microscopy, X-ray diffraction, atomic force microscopy, and a thermographic camera.
Structural and electronic properties of multilayer graphene on monolayer hexagonal boron nitride/nickel (111) interface system: A van der Waals density functional study
Authors: Yelgel Celal
Published: February 2016

The structural and electronic properties of multilayer graphene adsorbed on monolayer hexagonal boron nitride (h-BN)/Ni(111) interface system are investigated using the density functional theory with a recently developed non-local van der Waals density functional (rvv10). The most energetically favourable configuration for a monolayer h-BN/Ni(111) interface is found to be N atom atop the Ni atoms and B atom in fcc site with the interlayer distance of 2.04 Å and adsorption energy of 302 meV/BN. Our results show that increasing graphene layers on a monolayer h-BN/Ni(111) interface leads to a weakening of the interfacial interaction between the monolayer h-BN and Ni(111) surface. The adsorption energy of graphene layers on the h-BN/Ni(111) interface is found to be in the range of the 50–120 meV/C atom as the vertical distance from h-BN to the bottommost graphene layers decreases. With the adsorption of a multilayer graphene on the monolayer h-BN/Ni(111) interface system, the band gap of 0.12 eV and 0.25 eV opening in monolayer graphene and bilayer graphene near the K point is found with an upward shifting of the Fermi level. However, a stacking-sensitive band gap is opened in trilayer graphene. We obtain the band gap of 0.35 eV close to the K point with forming a Mexican hat band structure for ABC-stacked trilayer graphene.
Graphene by one-step chemical vapor deposition from ferrocene vapors: Properties and electrochemical evaluation
Authors: Pilatos George , Perdikaki Anna V. , Sapalidis Andreas , Pappas George S. , Giannakopoulou Tatiana , Tsoutsou Dimitra , Xenogiannopoulou Evangelia , Boukos Nikos , Dimoulas Athanasios , Trapalis Christos , Kanellopoulos Nick K. , Karanikolos Georgios N.
Published: February 2016

Growth of few-layer graphene using ferrocene as precursor by chemical vapor deposition is reported. The growth did not involve any additional carbon or catalyst source or external hydrocarbon gases. Parametric investigation was performed using different conditions, namely, varying growth temperature from 600 to1000 °C, and growth duration from 5 min to 3 h, as well as using fast quenching or gradual cooling after the thermal treatment, in order to examine the effect on the quality of the produced graphene. The growth took place on silicon wafers and resulted, under optimal conditions, in formation of graphene with 2–3 layers and high graphitic quality, as evidenced by Raman spectroscopy, with characteristic full width at half maximum of the 2D band of 49.46 cm−1, and I2D/IG and ID/IG intensity ratios of 1.15 and 0.26, respectively. Atomic force microscopy and X-ray photoelectron spectroscopy were employed to further evaluate graphene characteristics and enlighten growth mechanism. Electrochemical evaluation of the developed material was performed using cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic charge-discharge measurements.
Electrical method for the measurements of volume averaged electron density and effective coupled power to the plasma bulk
Authors: Henault M. , Wattieaux G. , Lecas T. , Renouard J. P. , Boufendi L.
Published: February 2016

Nanoparticles growing or injected in a low pressure cold plasma generated by a radiofrequency capacitively coupled capacitive discharge induce strong modifications in the electrical parameters of both plasma and discharge. In this paper, a non-intrusive method, based on the measurement of the plasma impedance, is used to determine the volume averaged electron density and effective coupled power to the plasma bulk. Good agreements are found when the results are compared to those given by other well-known and established methods.
Photothermal method for absorption measurements in anisotropic crystals
Authors: Stubenvoll M. , Schäfer B. , Mann K. , Novak O.
Published: February 2016

A measurement system for quantitative determination of both surface and bulk contributions to the photo-thermal absorption has been extended to anisotropic optical media. It bases upon a highly sensitive Hartmann-Shack wavefront sensor, accomplishing precise on-line monitoring of wavefront deformations of a collimated test beam transmitted perpendicularly through the laser-irradiated side of a cuboid sample. Caused by the temperature dependence of the refractive index as well as thermal expansion, the initially plane wavefront of the test beam is distorted. Sign and magnitude depend on index change and expansion. By comparison with thermal theory, a calibration of the measurement is possible, yielding a quantitative absolute measure of bulk and surface absorption losses from the transient wavefront distortion. Results for KTP and BBO single crystals are presented.
Start-up scenario of a high-power pulsed gyrotron for 300 GHz band collective Thomson scattering diagnostics in the large helical device
Authors: Dumbrajs O. , Saito T. , Tatematsu Y.
Published: February 2016

We present results of theoretical study of mode competition during the voltage rise of a 300-kW, 300-GHz gyrotron operating in the TE22,2,1 mode. Simulations tracking eight competing modes show that, with a proper choice of the magnetic field, stable excitation of the operating mode can be realized, despite the presence of parasitic modes in the resonator spectrum. A finite voltage rise time, 1 kV/4 ns referred to as the slow voltage rise case, is taken into account to simulate realistically the experimental condition. Simulation results with the finite voltage rise time are in good agreement with the experimental test, in which the gyrotron demonstrated reliable operation at power levels up to 300 kW. Moreover, interesting phenomena are observed. Along with voltage rise, the oscillation manner changes from backward wave oscillation to gyrotron oscillation. In the range of the magnetic field lower than the magnetic field strength at which the TE22,2 mode attains to the maximum power, mode competition with the TE21,2 mode takes place although many other competing modes exist in between the two modes. In addition to the slow voltage rise case, the fast voltage rise case, 10 kV/4 ns, and the instant voltage rise case are considered. For these cases, simulations also predict stable oscillation of the TE22,2 mode with the same power level with the slow voltage rise case. This indicates that stable oscillations of the TE22,2 mode can be obtained in a wide range of the voltage rise time.
Perspective: n-type oxide thermoelectrics via visual search strategies
Authors: Xing Guangzong , Sun Jifeng , Ong Khuong P. , Fan Xiaofeng , Zheng Weitao , Singh David J.
Published: February 2016

We discuss and present search strategies for finding new thermoelectric compositions based on first principles electronic structure and transport calculations. We illustrate them by application to a search for potential n-type oxide thermoelectric materials. This includes a screen based on visualization of electronic energy isosurfaces. We report compounds that show potential as thermoelectric materials along with detailed properties, including SrTiO3, which is a known thermoelectric, and appropriately doped KNbO3 and rutile TiO2.
Time-resolved local strain tracking microscopy for cell mechanics
Authors: Aydin O. , Aksoy B. , Akalin O. B. , Bayraktar H. , Alaca B. E.
Published: February 2016

A uniaxial cell stretching technique to measure time-resolved local substrate strain while simultaneously imaging adherent cells is presented. The experimental setup comprises a uniaxial stretcher platform compatible with inverted microscopy and transparent elastomer samples with embedded fluorescent beads. This integration enables the acquisition of real-time spatiotemporal data, which is then processed using a single-particle tracking algorithm to track the positions of fluorescent beads for the subsequent computation of local strain. The present local strain tracking method is demonstrated using polydimethylsiloxane (PDMS) samples of rectangular and dogbone geometries. The comparison of experimental results and finite element simulations for the two sample geometries illustrates the capability of the present system to accurately quantify local deformation even when the strain distribution is non-uniform over the sample. For a regular dogbone sample, the experimentally obtained value of local strain at the center of the sample is 77%, while the average strain calculated using the applied cross-head displacement is 48%. This observation indicates that considerable errors may arise when cross-head measurement is utilized to estimate strain in the case of non-uniform sample geometry. Finally, the compatibility of the proposed platform with biological samples is tested using a unibody PDMS sample with a well to contain cells and culture media. HeLa S3 cells are plated on collagen-coated samples and cell adhesion and proliferation are observed. Samples with adherent cells are then stretched to demonstrate simultaneous cell imaging and tracking of embedded fluorescent beads.
Design verification of large time constant thermal shields for optical reference cavities
Authors: Zhang J. , Wu W. , Shi X. H. , Zeng X. Y. , Deng K. , Lu Z. H.
Published: February 2016

In order to achieve high frequency stability in ultra-stable lasers, the Fabry-Pérot reference cavities shall be put inside vacuum chambers with large thermal time constants to reduce the sensitivity to external temperature fluctuations. Currently, the determination of thermal time constants of vacuum chambers is based either on theoretical calculation or time-consuming experiments. The first method can only apply to simple system, while the second method will take a lot of time to try out different designs. To overcome these limitations, we present thermal time constant simulation using finite element analysis (FEA) based on complete vacuum chamber models and verify the results with measured time constants. We measure the thermal time constants using ultrastable laser systems and a frequency comb. The thermal expansion coefficients of optical reference cavities are precisely measured to reduce the measurement error of time constants. The simulation results and the experimental results agree very well. With this knowledge, we simulate several simplified design models using FEA to obtain larger vacuum thermal time constants at room temperature, taking into account vacuum pressure, shielding layers, and support structure. We adopt the Taguchi method for shielding layer optimization and demonstrate that layer material and layer number dominate the contributions to the thermal time constant, compared with layer thickness and layer spacing.
Correlation between weighted spectral distribution and average path length in evolving networks
Authors: Jiao Bo , Shi Jianmai , Wu Xiaoqun , Nie Yuanping , Huang Chengdong , Du Jing , Zhou Ying , Guo Ronghua , Tao Yerong
Published: February 2016

The weighted spectral distribution (WSD) is a metric defined on the normalized Laplacian spectrum. In this study, synchronic random graphs are first used to rigorously analyze the metric's scaling feature, which indicates that the metric grows sublinearly as the network size increases, and the metric's scaling feature is demonstrated to be common in networks with Gaussian, exponential, and power-law degree distributions. Furthermore, a deterministic model of diachronic graphs is developed to illustrate the correlation between the slope coefficient of the metric's asymptotic line and the average path length, and the similarities and differences between synchronic and diachronic random graphs are investigated to better understand the correlation. Finally, numerical analysis is presented based on simulated and real-world data of evolving networks, which shows that the ratio of the WSD to the network size is a good indicator of the average path length.
The dynamics of the annular liquid layer inside a cylindrical capillary
Authors: Zhang Hua , Nikolov Alex , Feng Jianyuan , Wasan Darsh
Published: February 2016

When one fluid displaces another in a cylindrical capillary, a layer of the original fluid is often left behind on the capillary wall. We studied the dynamics of a cylindrical hexadecane layer deposited inside glass capillaries after the oil/air displacement experimentally and by a theoretical model prediction. Our experiments have shown that an annular oil layer is formed on the capillary wall after hexadecane is displaced by air. The oil layer subject to surface perturbation becomes unstable over time (Rayleigh instability), forming uniform, regularly spaced double concave meniscuses across the capillary that are bridged with dimples (collars). With time, the film between the meniscus and the dimple thins, but does not break, during the thinning process. The dynamics of the oil layer and the formation of the double concave meniscus with the dimple are more pronounced in a large capillary compared to those phenomena found in a small capillary. In order to reveal the phenomena of the film thinning and stability between the double concave meniscus and the dimple, we monitored an air bubble approaching a flat glass surface in hexadecane. We found that the oil film thinning in a cylindrical glass capillary and on a flat glass substrate was similar; the film did not break during the thinning process. The analysis also showed that the macroscopic contact angle (based on the Laplace solution-extrapolation to a solid substrate) was different from the microscopic contact angle (between the film and meniscus). We adapted the model proposed by Gauglitz and Radke [“An extended evolution equation for liquid film breakup in cylindrical capillaries,” Chem. Eng. Sci. 43, 1457 (1988)] for our system (oil-air displacement) and solved it numerically. The numerical result shows a stable film between the liquid bridge and the dimple, which is consistent with our experimental observations. We also estimated the meniscus-film-dimple thickness profile and found it was in fair agreement with the model prediction.
Note: Durability analysis of optical fiber hydrogen sensor based on Pd-Y alloy film
Authors: Huang Peng-cheng , Chen You-ping , Zhang Gang , Song Han , Liu Yi
Published: February 2016

The Pd-Y alloy sensing film has an excellent property for hydrogen detection, but just for one month, the sensing film’s property decreases seriously. To study the failure of the sensing film, the XPS spectra analysis was used to explore the chemical content of the Pd-Y alloy film, and analysis results demonstrate that the yttrium was oxidized. The paper presented that such an oxidized process was the potential reason of the failure of the sensing film. By understanding the reason of the failure of the sensing film better, we could improve the manufacturing process to enhance the property of hydrogen sensor.
Structure functions, scaling exponents and intermittency in the wake of a wind turbine array
Authors: Ali Naseem , Aseyev Aleksandr S. , Cal Raúl Bayoán
Published: February 2016

Hot-wire measurements obtained in a 3 × 3 wind turbine array boundary layer are utilized to analyze high order structure functions, intermittency effects as well as the probability density functions of velocity increments at different scales within the energy cascade. The intermittency exponent is found to be greater in the far-wake region in comparison with the near-wake. At hub height, the intermittency exponent is found to be null. Extended self-similarity scaling exponents of the second, fourth, and fifth order structure functions remain relatively constant as a function of height in the far-wake; whereas in the near-wake, these are highly affected by the passage of the rotor where tip vortices reside, thus showing a dependence on physical location. When comparing with proposed models, these generally overpredict the structure functions in the far-wake region. The probability density function distributions in the far-wake region display wider tails compared to the near-wake region, and the constant skewness hypothesis based on the local isotropy is disrupted in the wake.
Structural and electrical properties of Er doped La2Mo2O9 oxide ion conductors
Authors: Paul T. , Ghosh A.
Published: February 2016

We have studied structure and ionic conductivity of La2−xErxMo2O9 (0.05 ≤ x ≤ 0.25). The phase transition observed in La2Mo2O9 is suppressed in Er substituted samples. Cubic β phase in these samples is confirmed from Rietveld refinement at room temperature. The densification of the samples and grain–grain connectivity are confirmed from scanning electron microscopic study. The X-ray photoelectron microscopic analysis confirms the presence of La, Er, Mo, and O in these samples. The different vibration modes of MoO4 tetrahedral units are confirmed from Fourier transform infrared spectroscopy. The full-widths at half-maximum of all the major absorption bands show high composition dependence. The impedance spectroscopic study is presented in wide temperature and frequency ranges. The temperature dependence of the ionic conductivity is differentiated into three regimes. The effect of grain, grain boundary and electrode polarization on the conductivity is analyzed. The frequency dependence of the conductivity is analyzed using the random free-energy barrier model. The charge carrier relaxation time and its activation energy have been determined from the analysis of the conductivity spectra using the model.
An investigation of a thermally steerable electroactive polymer/shape memory polymer hybrid actuator
Authors: Ren Kailiang , Bortolin Robert S. , Zhang Q. M.
Published: February 2016

This paper investigates the thermal response of a hybrid actuator composed of an electroactive polymer (EAP) and a shape memory polymer (SMP). This study introduces the concept of using the large strain from a phase transition (ferroelectric to paraelectric phase) induced by temperature change in a poly(vinylidene fluoride-trifluoroethylene) film to tune the shape of an SMP film above its glass transition temperature (Tg). Based on the material characterization data, it is revealed that the thickness ratio of the EAP/SMP films plays a critical role in the displacement of the actuator. Further, it is also demonstrated that the displacement of the hybrid actuator can be tailored by varying the temperature, and finite element method simulation results fit well with the measurement data. This specially designed hybrid actuator shows great promise for future morphing aircraft applications.
High temperature stability of the dielectric and insulating properties of Ca(Ti, Zr)SiO5 ceramics
Authors: Kimura Junichi , Taniguchi Hiroki , Iijima Takashi , Shimizu Takao , Yasui Shintaro , Itoh Mitsuru , Funakubo Hiroshi
Published: February 2016

Useful dielectric properties for high-temperature ceramic capacitors are demonstrated in a non-perovskite oxide, Ca(Ti0.85 Zr0.15)SiO5, which is mainly composed of one-dimensional chains of oxygen octahedra that are mutually linked by SiO4 tetrahedra. Its dielectric constant and low temperature coefficient of capacitance were found to be 43 and −102 ppm/K, respectively, over the wide temperature range of 300–780 K. The high insulating performance was also indicated by the high resistivity, exceeding 1011 Ω cm up to 523 K. The systematic dielectric measurements for Ca(Ti1−x Zrx)SiO5 as functions of the composition and temperature indicate that the suppression of the anti-ferroelectric phase transition of CaTiSiO5 by Zr4+-substitution is a key to improve the temperature-stability and the high-resistivity in Ca(Ti1−x Zrx)SiO5. The present results shed light on the development of a designing principle for ceramic capacitors for the high-temperature use.
Ferroelectricity and tunneling electroresistance effect driven by asymmetric polar interfaces in all-oxide ferroelectric tunnel junctions
Authors: Tao L. L. , Wang J.
Published: February 2016

By constructing asymmetric polar interfaces, all-oxide ferroelectric tunnel junctions (FTJs) are proposed that can achieve a sizable tunneling electroresistance (TER) effect. Based on first-principles quantum transport calculations on a prototypical LaNiO3/BaTiO3/LaNiO3 junction, we predict that TER reaches 103% under a finite bias. Driven by the asymmetric polar interfaces, the resultant intrinsic electric field causes a highly asymmetric electrostatic potential in comparison to that of the FTJ with symmetric polar interfaces. As a result, the tunneling resistance changes significantly upon polarization reversal leading to sizable TER. The physical origin of the TER effect can be well understood in terms of local density of states, transport in momentum space, real-space scattering states and a free-electron tunneling model. Our results provide an insight into the understanding of ferroelectricity and the TER mechanism in FTJs and will be useful for FTJ-based devices design.
High sensitivity silicon single nanowire junctionless phototransistor
Authors: Das Samaresh , Dhyani Veerendra , Georgiev Yordan M. , Williams David A.
Published: February 2016

A high-gain photodetector based on junctionless MOSEFT has been presented in this work. Tri-gate junctionless nanowire phototransistors were fabricated on (100) silicon-on-insulator wafers with a buried oxide of thickness 145 nm and top silicon layer of thickness 10 nm. The gate stack consisted of a 10 nm SiO2 dielectric and a 50 nm poly-Si gate electrode. The channel length and doping concentration of junctionless n-MOSFETs was 1 μm and 3 × 1019 cm−3, respectively. The dark current of this device measured at room temperature was less than 1 pA. The measured internal gain of the device was about 35 for 860 nm light illumination. The photocurrent was 300 times larger than the dark current for only 30 nW incident power on the nanowire at 300 mV drain bias.