bluuebunny/crossref_metadata_2025 huggingface dataset:
Car body and bogie connection modification for track curves passability improvement
Authors: Hauser Vladimír , Nozhenko Olena S. , Kravchenko Kateryna O. , Loulová Mária , Gerlici Juraj , Lack Tomáš
Published: March 2018

For Tram cars, it is often necessary to operate in cities on strongly curved track, which is followed by an increased effect of the vehicle on the track. Especially, this increased effect occurs in spiral transition curves situated between direct and arc sections or between two arc sections of different radius. In such case, increased guiding forces, creep in the rail - wheel contact, wear and noise generation can be observed. Exactly with the aim to reduce these undesirable effects we designed a tram bogie with steered wheelsets. This paper deals with a modification of its coupling to vehicle body in order to improve vehicle dynamics in transition curves. Proposed innovative construction of this coupling unit is registered by authors under Utility Model Nr. u201609015 and Utility Model Nr. u201703246. Description of the proposed way for a vehicle to pass through curved track with regard to bogie-body coupling and wheelset steering mechanisms with usage of multibody computing software is given in this paper.
Contribution to numerical study of vehicle vertical stochastic vibration
Authors: Sapietová Alžbeta , Sága Milan , Stančeková Dana , Sapieta Milan
Published: March 2018

The goal of the paper is to present an application of the software MB_DYN inbuilt in MATLAB for stochastic response of the chosen vehicle computational model. The input kinematics parameters will be road irregularity with random character. The dynamic model parameters are considered as deterministic. The analysed vehicle model assumes 10 DOF. The stochastic response in time and frequency domain was solved by program MB_DYN in MATLAB using Monte Carlo method. Applying the simulation techniques the influence study of the vehicles speed and road quality in chosen points was realised.
Timing belt in power transmission and conveying system
Authors: Domek Grzegorz , Krawiec Piotr , Wilczyński Michał
Published: March 2018

This paper presents the problem of phenomena occurring at the contact of a timing belt and a pulley. Depending on a belt size range these phenomena differ significantly. There is no indication as to what solutions are optimal for drive belts. The analysis of the coupling process and performance tests have shown that the drive belt should have a cord of very good mechanical properties and its raceway side should be made from the material of a low friction coefficient against the pulley material. A flat belt in power transmission and conveying systems cooperates with several elements consisting of timing pulleys, tensioners or guiding rails. In gear with timing belts they depend strongly on characteristics of the process as well as the type of friction. In recent constructions, producers of timing belts are very much concerned about achieving as much slippery surface as possible. The work describes the problem of friction on different surfaces as well as its influence on gear lifetime. Research results confirm that on many surfaces bigger coefficient of friction is expected.
Improving the quality of cutting flat glass
Authors: Svoboda Martin , Soukup Josef , Sapieta Milan
Published: March 2018

The article deals with improving the quality of the cut flat glass. The aim of the study was to determine mechanism of origin temporary and permanent stress in the glass. This affects the quality of the cut flat glass. Of the commonly measured process parameters were adjusted following an evaluation, better cooling of flat glass between the furnace and the point of cutting into a prescribed format glass. The results are applicable for flat glass production lines.
A concept of smart multiaxial impact damper made of vacuum packed particles
Authors: Bartkowski Piotr , Zalewski Robert
Published: March 2018

The conceptual design of smart crash energy absorber made of Vacuum Packed Particles (VPP) is presented in this work. This structure is composed of granular material inside a plastomer sleeve. The absorber can change the flexural stiffness and as a result the amount of dissipated energy depending on the impact conditions. The special properties of the granular structure create the possibility of various applications as different working modes can be used. When the pressure inside is equal or higher than atmospheric pressure the system behaves similarly to a liquid, otherwise it has properties similar to viscoplastic solid. The physical properties of the structure may be rapidly changed by adjusting the pressure inside the system. Due to these properties Vacuum Packed Particles is considered to be a smart material.
Examples of modern methods of measuring deformations
Authors: Domański Tomasz
Published: March 2018

The work presents examples of possibilities created by multi-unit 3D correlation system. Experience is the non-contact measurement of displacement and strains of slender compression bars or tensile samples. Experimental research show that as a result of axial compression of slender elements with the length substantially exceeding the cross-sectional dimensions, element destruction occurs at loads less than the respective compressive strength, resulting in deformation of the object. We present the results of numerical analysis, compared with exercise of carrying on a test bench.
Low-cycle fatigue behaviour of laser welded high-strength steel DOMEX 700 MC
Authors: Kopas Peter , Sága Milan , Nový František , Leitner Bohuš
Published: March 2018

The article presents the results of research on low cycle fatigue strength of laser welded joints vs. non-welded material of high-strength steel DOMEX 700 MC. The tests were performed under load controlled using the total strain amplitude ɛac. The operating principle of the special electro-mechanic fatigue testing equipment with a suitable clamping system was working on 35 Hz frequency. Fatigue life analysis was conducted based on the Manson-Coffin-Basquin equation, which made it possible to determine fatigue parameters. Studies have shown differences in the fatigue life of original specimens and laser welded joints analysed, where laser welded joints showed lower fatigue resistance. In this article a numerical analysis of stresses generated in bending fatigue specimens has been performed employing the commercially available FEM-program ADINA.
Effect of bentonite modified by silane on rubber blends properties
Authors: Mičicová Zuzana , Božeková Slavomíra , Pajtášová Mariana , Ondrušová Darina
Published: March 2018

The presented paper deals with the preparation of bentonite modified by silane and its application into polymer matrix. Natural bentonite was modified with 3-(Trimethoxysilyl) propyl-methacrylate in two different solutions. These two solutions had the same composition (ethanol, water and 3-(Trimethoxysilyl) propyl-methacrylate) but in one solution, pH was modified. These bentonites modified by silane were characterized by Fourier transform infrared spectroscopy. The modified bentonites were mixed into rubber matrix as partial replacement of commonly used filler – carbon black of the N339 type. The polymer blends were investigated from the aspect of the rheological and curing characteristics (minimum torque ML, maximum torque MH, optimum time of cure t(c90), processing safety of blend ts,). Moreover, the quality of the silanization reactions was investigated. Measurements were done using PRPA 2000.
Transmuted Weibull distribution and its applications
Authors: Pobočíková Ivana , Sedliačková Zuzana , Michalková Mária
Published: March 2018

In this paper we study new distribution called transmuted Weibull distribution. Some properties of this distribution are described. The usefulness of the distribution for modelling data is illustrated using real data set.
Application of the vibration method for damage identification of a beam with a variable cross-sectional area
Authors: Zamorska Izabela , Cekus Dawid , Miara Mateusz
Published: March 2018

The subject of the paper is an application of the non-destructive vibration method for identifying the location of two cracks occurring in a beam. The vibration method is based on knowledge of a certain number of vibration frequencies of an undamaged element and the knowledge of the same number of vibration frequencies of an element with a defect. The analyzed beam, with a variable cross-sectional area, has been described according to the Bernoulli-Euler theory. To determine the values of free vibration frequencies the analytical solution, with the help of the Green’s function method, has been used.
Les productions françaises d’oléagineux de spécialité : des démarches en filière pour créer de la valeur dans nos territoires
Authors: Tonin Perrine
Published: March 2018

Dans un contexte de demande de diversification de la part du consommateur, de recherche de nouveaux débouchés pour les producteurs et de mondialisation des marchés oléagineux, les acteurs de la filière française ont développé des productions de spécialité afin de redonner de la valeur ajoutée à la filière. Cette analyse dresse un panorama de ces productions à travers quatre exemples : la filière oléique pour des qualités nutritionnelles et fonctionnelles reconnues, la filière érucique pour une diversité de débouchés en oléochimie, la filière Fleur de Colza – démarche de long terme de partenariat agricole – et la filière bio – un marché jeune, dynamique, en cours de structuration. Dans chaque cas, la valorisation pour le producteur nécessite une démarche de filière avec l’accompagnement de l’ensemble des acteurs afin de valoriser l’origine française par la traçabilité, apporter conseil et formation aux agriculteurs, optimiser la supply chain, soutenir la recherche variétale et développer la contractualisation pluriannuelle.
Reducing the Bullwhip effect in a supply chain network by application of optimal control theory
Authors: Sabbaghnia Ali , Razmi Jafar , Babazadeh Reza , Moshiri Behzad
Published: March 2018

Controlling the bullwhip effect and reducing the propagated inventory levels throughout the supply chain layers has an important role in reducing the total inventory costs of a supply chain. In this study, an optimal controller that considers demand as control variable is designed to dampen propagated inventory fluctuations for each node throughout the supply chain network. The model proves to be very useful in revealing the dynamic characteristics of the chain and provides a proper interface to study decisions taken into account at each node of the supply chain in different periods by decision makers (DMs). In the proposed approach, two feedback loops and online updated values of net stock quantities are used for calculation of the orders. To investigate the efficiency of the proposed approach, a real case of bicycle industry is conducted. The acquired results justify the efficiency of the proposed approach in controlling and dampening the bullwhip effect and reducing inventory levels, net stock quantities and inventory attributed costs throughout the supply chain network layers.
Application of GC/Q-ToF Combined with Advanced Data Mining and Chemometric Tools in the Characterization and Quality Control of Bay Leaves
Authors: Wang Mei , Raman Vijayasankar , Zhao Jianping , Avula Bharathi , Wang Yan-Hong , Wylie Philip , Khan Ikhlas
Published: March 2018

Correct identification of the true bay leaf (Laurus nobilis) and its substitutes is important not only for the quality control of the products, but also for the safety of the consumers. L. nobilis is often substituted or confused with other species, such as Cinnamomum tamala, Pimenta racemosa, Syzygium polyanthum, and Umbellularia californica. In the present study, the potential of gas chromatography combined with quadrupole time-of-flight mass spectrometry for the profiling of various bay leaf products was evaluated for the first time. Thirty-nine authenticated samples representing the true bay leaf and the four commonly substituted species were analyzed. An automatic feature extraction algorithm was applied for data mining and pretreatment in order to identify the most characteristic compounds representing different bay leaf groups. This set of data was employed to construct a sample class prediction model based on stepwise reduction of data dimensionality followed by principal component analysis and partial least squares discriminant analysis. The statistical model, with demonstrated excellent accuracies in recognition and prediction abilities, enabled the correct classification of commercial samples including complex mixtures and essential oils. In addition, in-house developed personal compound database and library with retention time locking offered the advantage of combining retention time matching with accurate mass matching, resulting in high confidence of compound identification for each bay leaf subgroup. At least three marker compounds were identified for each bay leaf species that could be used to discriminate among them.
A Bivalent Role of Genistein in Sprouting Angiogenesis
Authors: Berndt Sarah , Issa Mark , Carpentier Gilles , Cuendet Muriel
Published: March 2018

The effects of genistein on angiogenesis remain poorly understood. Some studies claim an antiangiogenic effect and others claim a pro-angiogenic one. Thus, the aim of this study was to determine if genistein may exhibit bivalent angiogenic effects. To address this question, genistein angiogenic modulatory effects were examined using an in vitro 3D angiogenesis model using human umbilical vein endothelial cells. In this model, a bivalent effect of genistein was demonstrated on sprouting angiogenesis, with angiogenic stimulation at low concentrations (0.001 – 1 µM) and inhibition at higher ones (25 – 100 µM). Enhancement of the endothelial tube formation correlated with an increase in human umbilical vein endothelial cell metabolic activity and proliferation. Inhibition of angiogenesis correlated with a decreased metabolic activity, proliferation, and migration. Moreover, high concentrations of genistein influenced human umbilical vein endothelial cell morphology. Expression of genes involved in the angiogenic process in response to genistein was measured to study the mechanism of action. Secretome profiling revealed that angiogenic regulators were modulated with genistein treatment. These results suggested a bivalent effect of genistein on human umbilical vein endothelial cell growth and angiogenesis, and further investigations on the benefit of genistein for cancer chemoprevention, cancer treatment, or pro-angiogenic therapies have to be carefully considered.
Synthesis of 3-(Arylthio)propionic Acids from Nonactivated Aryl Iodides and their Use as Odorless Aryl Mercaptan Surrogates
Authors: Menczinger B. , Nemes A. , Csámpai A. , Rábai J.
Published: March 2018

The reaction of aryl iodides, 3-mercaptopropionic acid, and Cu2O in refluxing pyridine resulted in the formation of 3-(arylthio)propionic acids in good to excellent yield. The latter 3-(arylthio)propionic acids — as novel aryl mercaptan equivalents — gave aryl mercaptans or diaryl disulfides, respectively, on reductive (Na2S) or oxidative (I2) cleavage in alkaline media. The symmetrical disulfides can also be prepared by oxidizing their precursor mercaptans with phenyltrimethyl­ammonium­tribromide in pyridine at ambient temperature.
Efficient Access to cis-Hydrobenzo[b]oxepines: Rhodium(I)-Catalyzed Cyclization of Cyclohexadienone-Tethered o-Tolyl-Substituted Alkynes
Authors: Wang Jia-Xin , Tan Yun-Xuan , Liao Wei-Wei , Tian Ping , Lin Guo-Qiang , Zhao Qian
Published: March 2018

An efficient access to cis-hydrobenzo[b]oxepine frameworks has been established through rhodium(I)-catalyzed cyclization of cyclohexadienone-tethered o-tolyl-substituted alkynes (1,6-enynes). The cascade process involves regioselective α-arylrhodation of the alkyne, 1,4-rhodium migration, and conjugate addition to cyclohexadienone.
Palladium-Catalyzed Csp3–H Bond mono-Aroyloxylation of O-Alkyl Substituted 2,4,6-Trimethoxybenzaldoxime Ethers
Authors: Qiao Wen-Li , Shao Ling-Yan , Hu Ya-Hua , Xing Li-Hao , Deng Ke-Zuan , Liu Hong-Wei , Liao Dao-Hua , Ji Ya-Fei
Published: March 2018

A palladium-catalyzed Csp3–H bond mono-aroyloxylation of O-alkyl substituted oxime ethers has been developed by using 2,4,6-trimethoxybenzaldoxime as an exo-type directing group with exclusive site-selectivity. With the wide range of masked aliphatic alcohol substrates and aromatic acid coupling partners, the protocol allows rapid access to various 2-alkyl substituted glycol derivatives in synthetically useful to good yields. The employed directing group is readily removed, accordingly affording valuable functionalized aliphatic alcohols. When the solvent from hybrid DCE/HFIP to CH3CN, non-directed oxidative cross-coupling is observed between the electron-rich aromatic ring of substrates and aromatic acid partners.
Die Ableitung olfaktorisch evozierter Potenziale in Patienten mit limbischer Enzephalitis
Authors: Schmidt Felix , Harms Lutz , Prüss Harald , Geran Rohat , Olze Heidi , Maas Matthew , Uecker Florian
Published: March 2018

Ziel der Studie In dieser Studie wurde erstmals das Riechvermögen bei Patienten mit limbischer Enzephalitis (LE) mittels olfaktorisch evozierter Potenziale (OERP) untersucht.

Methodik Bei 19 LE Patienten (9 weibliche, 10 männliche Patienten, mittleres Alter 47 Jahre) und 19 gesunden Kotrollprobanden (GK) wurde das Riechvermögen mittels psychophysischer Schwellen-Diskrimination-Identifikations-Testung (SDI) und mittels OERPs bestimmt.

Ergebnisse 10 LE Pat. (53%) hatten eine Hyposmie, 2 Pat. (11%) eine funktionelle Anosmie und 7 Pat. (36%) waren normosmisch. Der SDI-Mittelwert±Standardabweichung betrug bei den LE-Patienten 27,3±6,7; bei den GK 34,7±2,2. Der SDI-Wert der LE Patienten war im Vergleich zu den GK signifikant vermindert (p<0,0001). Alle untersuchten Patienten mit eingeschränktem Riechvermögen zeigten pathologische OERPs.

Schlussfolgerung Riechstörungen konnten gehäuft bei LE Patienten nachgewiesen werden. Möglicherweise sind hierfür strukturelle Schädigungen des limbischen Systems, das an der Weiterverarbeitung von olfaktorischen Informationen beteiligt ist, ursächlich. Die Ableitung von OERPs erwies sich als geeignetes objektives Untersuchungsverfahren zur Detektion von Riechstörungen bei LE Patienten.
Measurement of nanoscale molten polymer droplet spreading using atomic force microscopy
Authors: Soleymaniha Mohammadreza , Felts Jonathan R.
Published: March 2018

We present a technique for measuring molten polymer spreading dynamics with nanometer scale spatial resolution at elevated temperatures using atomic force microscopy (AFM). The experimental setup is used to measure the spreading dynamics of polystyrene droplets with 2 μm diameters at 115-175 °C on sapphire, silicon oxide, and mica. Custom image processing algorithms determine the droplet height, radius, volume, and contact angle of each AFM image over time to calculate the droplet spreading dynamics. The contact angle evolution follows a power law with time with experimentally determined values of −0.29 ± 0.01, −0.08 ± 0.02, and −0.21 ± 0.01 for sapphire, silicon oxide, and mica, respectively. The non-zero steady state contact angles result in a slower evolution of contact angle with time consistent with theories combining molecular kinetic and hydrodynamic models. Monitoring the cantilever phase provides additional information about the local mechanics of the droplet surface. We observe local crystallinity on the molten droplet surface, where crystalline structures appear to nucleate at the contact line and migrate toward the top of the droplet. Increasing the temperature from 115 °C to 175 °C reduced surface crystallinity from 35% to 12%, consistent with increasingly energetically favorable amorphous phase as the temperature approaches the melting temperature. This platform provides a way to measure spreading dynamics of extremely small volumes of heterogeneously complex fluids not possible through other means.
Photoacoustic technique to measure temperature effects on microbubble viscoelastic properties
Authors: Lum Jordan S. , Stobbe David M. , Borden Mark A. , Murray Todd W.
Published: March 2018

Phospholipid-coated microbubbles are being developed for several biomedical applications, but little is known about the effect of temperature on the viscoelastic properties of the shell. Here, we report on the use of a photoacoustic technique to study the shell properties of individual microbubbles as a function of temperature. The microbubbles were driven into small-amplitude oscillations by ultrasound waves generated from the absorption of an intensity-modulated infrared laser, and these oscillations were detected by forward-light scattering of a second blue laser. The drive laser modulation frequency was swept to determine the resonant response of 2–4 μm radius microbubbles. Lipid shell elasticity and viscosity were determined by modeling the microbubble response as a linear harmonic oscillator. The results from slow heating showed a linear decrease in elasticity and viscosity between 21 and 53 °C and a corresponding increase in the maximum oscillation amplitude. Rapid heating to 38 °C, on the other hand, showed a transient response in the viscoelastic properties, suggesting shell rupture and reformation during microbubble growth and subsequent dissolution. These effects are important for biomedical applications, which require warming of the microbubbles to body temperature.
String-like collective motion in the α- and β-relaxation of a coarse-grained polymer melt
Authors: Pazmiño Betancourt Beatriz A. , Starr Francis W. , Douglas Jack F.
Published: March 2018

Relaxation in glass-forming liquids occurs as a multi-stage hierarchical process involving cooperative molecular motion. First, there is a “fast” relaxation process dominated by the inertial motion of the molecules whose amplitude grows upon heating, followed by a longer time α-relaxation process involving both large-scale diffusive molecular motion and momentum diffusion. Our molecular dynamics simulations of a coarse-grained glass-forming polymer melt indicate that the fast, collective motion becomes progressively suppressed upon cooling, necessitating large-scale collective motion by molecular diffusion for the material to relax approaching the glass-transition. In each relaxation regime, the decay of the collective intermediate scattering function occurs through collective particle exchange motions having a similar geometrical form, and quantitative relationships are derived relating the fast “stringlet” collective motion to the larger scale string-like collective motion at longer times, which governs the temperature-dependent activation energies associated with both thermally activated molecular diffusion and momentum diffusion.
Large energy density in three-plate nanocapacitors due to Coulomb blockade
Authors: Hubler A. , Foreman S. , Liu J. , Wortsmann L.
Published: March 2018

The maximum energy density of a capacitor is comparatively small due to large leak currents that thermally degrade the system. We study a three-plate system with nanometer gaps between the plates. Two negatively charged plates (cathodes) sandwich a thin, positively charged inner plate (anode). The dynamics of the electrons, in gaps of such a capacitor, are quantized, even at room temperature, because the dimensions are so small. Under strong fields, eigenstates between the electrodes fill and reduce the leak current between the anode and cathode. We show that the self-discharge time for a three-plate nanocapacitor can be significantly longer than a comparable two-plate nanocapacitor, thus increasing maximum energy density of such a nanocapacitor.
Temperature-dependent and optimized thermal emission by spheres
Authors: Nguyen K.L. , Merchiers O. , Chapuis P.-O.
Published: March 2018

We investigate the temperature and size dependencies of thermal emission by homogeneous spheres as a function of their dielectric properties. Different power laws obtained in this work show that the emitted power can depart strongly from the usual fourth power of temperature given by Planck's law and from the square or the cube of the radius. We also show how to optimize the thermal emission by selecting permittivities leading to resonances, which allow for the so-called super-Planckian regime. These results will be useful as spheres, i.e. the simplest finite objects, are often considered as building blocks of more complex objects.
Single-particle dispersion in compressible turbulence
Authors: Zhang Qingqing , Xiao Zuoli
Published: March 2018

Single-particle dispersion statistics in compressible box turbulence are studied using direct numerical simulation. Focus is placed on the detailed discussion of effects of the particle Stokes number and turbulent Mach number, as well as the forcing type. When solenoidal forcing is adopted, it is found that the single-particle dispersion undergoes a transition from the ballistic regime at short times to the diffusive regime at long times, in agreement with Taylor’s particle dispersion argument. The strongest dispersion of heavy particles is announced when the Stokes number is of order 1, which is similar to the scenario in incompressible turbulence. The dispersion tends to be suppressed as the Mach number increases. When hybrid solenoidal and compressive forcing at a ratio of 1/2 is employed, the flow field shows apparent anisotropic property, characterized by the appearance of large shock wave structures. Accordingly, the single-particle dispersion shows extremely different behavior from the solenoidal forcing case.
Effect of edge defects on band structure of zigzag graphene nanoribbons
Authors: Wadhwa Payal , Kumar Shailesh , Dhilip Kumar T. J. , Shukla Alok , Kumar Rakesh
Published: March 2018

In this article, we report band structure studies of zigzag graphene nanoribbons (ZGNRs) on introducing defects (sp3 hybridized carbon atoms) in different concentrations at edges by varying the ratio of sp3 to sp2 hybridized carbon atoms. On the basis of theoretical analyses, bandgap values of ZGNRs are found to be strongly dependent on the relative arrangement of sp3 to sp2 hybridized carbon atoms at the edges for a defect concentration; so the findings would greatly help in understanding the bandgap of nanoribbons for their electronic applications.
Lifetime degradation of n-type Czochralski silicon after hydrogenation
Authors: Vaqueiro-Contreras M. , Markevich V. P. , Mullins J. , Halsall M. P. , Murin L. I. , Falster R. , Binns J. , Coutinho J. , Peaker A. R.
Published: March 2018

Hydrogen plays an important role in the passivation of interface states in silicon-based metal-oxide semiconductor technologies and passivation of surface and interface states in solar silicon. We have shown recently [Vaqueiro-Contreras et al., Phys. Status Solidi RRL 11, 1700133 (2017)] that hydrogenation of n-type silicon slices containing relatively large concentrations of carbon and oxygen impurity atoms {[Cs] ≥ 1 × 1016 cm−3 and [Oi] ≥ 1017 cm−3} can produce a family of C-O-H defects, which act as powerful recombination centres reducing the minority carrier lifetime. In this work, evidence of the silicon's lifetime deterioration after hydrogen injection from SiNx coating, which is widely used in solar cell manufacturing, has been obtained from microwave photoconductance decay measurements. We have characterised the hydrogenation induced deep level defects in n-type Czochralski-grown Si samples through a series of deep level transient spectroscopy (DLTS), minority carrier transient spectroscopy (MCTS), and high-resolution Laplace DLTS/MCTS measurements. It has been found that along with the hydrogen-related hole traps, H1 and H2, in the lower half of the gap reported by us previously, hydrogenation gives rise to two electron traps, E1 and E2, in the upper half of the gap. The activation energies for electron emission from the E1 and E2 trap levels have been determined as 0.12, and 0.14 eV, respectively. We argue that the E1/H1 and E2/H2 pairs of electron/hole traps are related to two energy levels of two complexes, each incorporating carbon, oxygen, and hydrogen atoms. Our results show that the detrimental effect of the C-O-H defects on the minority carrier lifetime in n-type Si:O + C materials can be very significant, and the carbon concentration in Czochralski-grown silicon is a key parameter in the formation of the recombination centers.
Non-additive non-interacting kinetic energy of rare gas dimers
Authors: Jiang Kaili , Nafziger Jonathan , Wasserman Adam
Published: March 2018

Approximations of the non-additive non-interacting kinetic energy (NAKE) as an explicit functional of the density are the basis of several electronic structure methods that provide improved computational efficiency over standard Kohn-Sham calculations. However, within most fragment-based formalisms, there is no unique exact NAKE, making it difficult to develop general, robust approximations for it. When adjustments are made to the embedding formalisms to guarantee uniqueness, approximate functionals may be more meaningfully compared to the exact unique NAKE. We use numerically accurate inversions to study the exact NAKE of several rare-gas dimers within partition density functional theory, a method that provides the uniqueness for the exact NAKE. We find that the NAKE decreases nearly exponentially with atomic separation for the rare-gas dimers. We compute the logarithmic derivative of the NAKE with respect to the bond length for our numerically accurate inversions as well as for several approximate NAKE functionals. We show that standard approximate NAKE functionals do not reproduce the correct behavior for this logarithmic derivative and propose two new NAKE functionals that do. The first of these is based on a re-parametrization of a conjoint Perdew-Burke-Ernzerhof (PBE) functional. The second is a simple, physically motivated non-decomposable NAKE functional that matches the asymptotic decay constant without fitting.
A technique for plasma velocity-space cross-correlation
Authors: Mattingly Sean , Skiff Fred
Published: March 2018

An advance in experimental plasma diagnostics is presented and used to make the first measurement of a plasma velocity-space cross-correlation matrix. The velocity space correlation function can detect collective fluctuations of plasmas through a localized measurement. An empirical decomposition, singular value decomposition, is applied to this Hermitian matrix in order to obtain the plasma fluctuation eigenmode structure on the ion distribution function. A basic theory is introduced and compared to the modes obtained by the experiment. A full characterization of these modes is left for future work, but an outline of this endeavor is provided. Finally, the requirements for this experimental technique in other plasma regimes are discussed.
Non-inductively driven tokamak plasmas at near-unity βt in the Pegasus toroidal experiment
Authors: Reusch J. A. , Bodner G. M. , Bongard M. W. , Burke M. G. , Fonck R. J. , Pachicano J. L. , Perry J. M. , Pierren C. , Rhodes A. T. , Richner N. J. , Rodriguez Sanchez C. , Schlossberg D. J. , Weberski J. D.
Published: March 2018

A major goal of the spherical tokamak (ST) research program is accessing a state of low internal inductance ℓi, high elongation κ, and high toroidal and normalized beta (βt and βN) without solenoidal current drive. Local helicity injection (LHI) in the Pegasus ST [Garstka et al., Nucl. Fusion 46, S603 (2006)] provides non-solenoidally driven plasmas that exhibit these characteristics. LHI utilizes compact, edge-localized current sources for plasma startup and sustainment. It results in hollow current density profiles with low ℓi. The low aspect ratio (R0/a∼1.2) of Pegasus allows access to high κ and high normalized plasma currents (IN=Ip/aBT>14). Magnetic reconnection during LHI provides auxiliary ion heating. Together, these features provide access to very high βt plasmas. Equilibrium analyses indicate that βt up to ∼100% is achieved. These high βt discharges disrupt at the ideal no-wall β limit at βN∼7.
A low cost, membranes based serum separator modular
Authors: Su Xiaosong , Zhang Shiyin , Ge Shengxiang , Chen Mengyuan , Zhang Jianzhong , Zhang Jun , Xia Ningshao
Published: March 2018

To fulfill the requirement of sample preparation in a microfluidic analysis system designed for “sample in, answer out” testing which was urgently needed by resource limited clinical facilities, we proposed a critical low cost, membrane-based serum separator design in this article. With a specially designed microchip, this device can easily separate serum from the whole blood sample in 5 min. Different from techniques which have been reported earlier, this approach does not require either centrifugation or sample dilution which may cause hemolysis or decreased testing sensitivity. By applying 300 μl of the whole blood sample, 50–70 μl of serum can be recovered from each device, and the serum volume recovery rate compared with centrifuged control is around 73% which is sufficient for most of the microfluidic-based assays. The protein recovery rate ranged from 70% to 95% which was compared with centrifuged control. The evaluation results indicate that this sample preparation device can offer sufficient amount of purified serum sample for any kind of diagnostic assays such as immunoassay and serum nucleic acid assay.
Prompt increase of ultrashort laser pulse transmission through thin silver films
Authors: Bezhanov S. G. , Danilov P. A. , Klekovkin A. V. , Kudryashov S. I. , Rudenko A. A. , Uryupin S. A.
Published: March 2018

We study experimentally and numerically the increase in ultrashort laser pulse transmissivity through thin silver films caused by the heating of electrons. Low to moderate energy femtosecond laser pulse transmission measurements through 40–125 nm thickness silver films were carried out. We compare the experimental data with the values of transmitted fraction of energy obtained by solving the equations for the field together with the two-temperature model. The measured values were fitted with sufficient accuracy by varying the electron-electron collision frequency whose exact values are usually poorly known. Since transmissivity experiences more pronounced changes with the increase in temperature compared to reflectivity, we suggest this technique for studying the properties of nonequilibrium metals.
Room temperature operation of InxGa1−xSb/InAs type-II quantum well infrared photodetectors grown by MOCVD
Authors: Wu D. H. , Zhang Y. Y. , Razeghi M.
Published: March 2018

We demonstrate room temperature operation of In0.5Ga0.5Sb/InAs type-II quantum well photodetectors on an InAs substrate grown by metal-organic chemical vapor deposition. At 300 K, the detector exhibits a dark current density of 0.12 A/cm2 and a peak responsivity of 0.72 A/W corresponding to a quantum efficiency of 23.3%, with the calculated specific detectivity of 2.4 × 109 cm Hz1/2/W at 3.81 μm.
Preparation of indium tin oxide contact to n-CdZnTe gamma-ray detector
Authors: Li Leqi , Xu Yadong , Zhang Binbin , Wang Aoqiu , Dong Jiangpeng , Yu Hui , Jie Wanqi
Published: March 2018

The nonmetal electrode material Indium Tin Oxide (ITO) has advantages of excellent conductivity, higher adhesion, and interface stability, showing potential to replace the metallic contacts for fabrication of CdZnTe (CZT) X/γ-ray detectors. In this work, high quality ITO electrodes for n-type CZT crystals were prepared by magnetron sputtering under a sputtering power of 75 W and a sputtering pressure of 0.6 Pa. A low dark current of ∼1 nA is achieved for the 5 × 5 × 2 mm3 ITO/CZT/ITO planar device under 100 V bias. The characteristics of Schottky contact are presented in the room temperature I-V curves, which are similar to those of the Au contact detectors. Based on the thermoelectric emission theory, the contact barrier and resistance of ITO electrodes are evaluated to be 0.902–0.939 eV and 0.87–3.56 × 108 Ω, respectively, which are consistent with the values of the Au electrodes. The ITO/CZT/ITO structure detector exhibits a superior energy resolution of 6.5% illuminated by the uncollimated 241Am @59.5 keV γ-ray source, which is comparable to the CZT detector with Au electrodes.
Nitrate is an important nitrogen source for Arctic tundra plants
Authors: Liu Xue-Yan , Koba Keisuke , Koyama Lina A. , Hobbie Sarah E. , Weiss Marissa S. , Inagaki Yoshiyuki , Shaver Gaius R. , Giblin Anne E. , Hobara Satoru , Nadelhoffer Knute J. , Sommerkorn Martin , Rastetter Edward B. , Kling George W. , Laundre James A. , Yano Yuriko , Makabe Akiko , Yano Midori , Liu Cong-Qiang
Published: March 2018

Significance

How terrestrial plants use N and respond to soil N loading is central to evaluating and predicting changing ecosystem structure and function with climate warming and N pollution. Here, evidence from NO
3
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in plant tissues has uncovered the uptake and assimilation of soil NO
3
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by Arctic tundra plants, which has long been assumed negligible. Soil NO
3
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contributed about one-third of the bulk N used by tundra plants of northern Alaska. Accordingly, the importance of soil NO
3
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for tundra plants should be considered in future studies on N and C cycling in Arctic ecosystems where C sequestration is strongly determined by N availability.
Exploring the role of ‘brokers’ in developing a localised curriculum
Authors: Leat David , Thomas Ulrike
Published: March 2018

There is a move in some countries, including England, towards less curriculum control by government. This stands in contrast to a national curriculum which may be universally applied in all schools within a state/country. National curricula tend to use either content‐based (subject mastery) or process (skills)‐based models. More localised curricula have the potential to be more issue‐ and problem‐centred using local resources and people as part of their building blocks. However, marketisation and globalisation typified by Programme for International Student Assessment (PISA) ‘effect’ on national policies have discouraged teachers' creativity and curriculum innovation and negated teacher agency. Unfortunately, schools and community partners can find it hard to work together because of logistical, communication and cultural impediments, which gives significance to the role of curriculum brokers who can bridge these divides. This paper offers a case study of two brokers in order to describe, understand and conceptualise their role in curriculum development. The wider implications for curriculum development are outlined.
Phospholipid flippases and Sfk1p, a novel regulator of phospholipid asymmetry, contribute to low permeability of the plasma membrane
Authors: Mioka Tetsuo , Fujimura-Kamada Konomi , Mizugaki Nahiro , Kishimoto Takuma , Sano Takamitsu , Nunome Hitoshi , Williams David E. , Andersen Raymond J. , Tanaka Kazuma
Published: March 2018

Phospholipid flippase (type 4 P-type ATPase) plays a major role in the generation of phospholipid asymmetry in eukaryotic cell membranes. Loss of Lem3p-Dnf1/2p flippases leads to the exposure of phosphatidylserine (PS) and phosphatidylethanolamine (PE) on the cell surface in yeast, resulting in sensitivity to PS- or PE-binding peptides. We isolated Sfk1p, a conserved membrane protein in the TMEM150/FRAG1/DRAM family, as a multicopy suppressor of this sensitivity. Overexpression of SFK1 decreased PS/PE exposure in lem3Δ mutant cells. Consistent with this, lem3Δ sfk1Δ double mutant cells exposed more PS/PE than the lem3Δ mutant. Sfk1p was previously implicated in the regulation of the phosphatidylinositol-4 kinase Stt4p, but the effect of Sfk1p on PS/PE exposure in lem3Δ was independent of Stt4p. Surprisingly, Sfk1p did not facilitate phospholipid flipping but instead repressed it, even under ATP-depleted conditions. We propose that Sfk1p negatively regulates transbilayer movement of phospholipids irrespective of directions. In addition, we showed that the permeability of the plasma membrane was dramatically elevated in the lem3Δ sfk1Δ double mutant in comparison with the corresponding single mutants. Interestingly, total ergosterol was decreased in the lem3Δ sfk1Δ mutant. Our results suggest that phospholipid asymmetry is required for the maintenance of low plasma membrane permeability.
Intraflagellar transport is deeply integrated in hedgehog signaling
Authors: Eguether Thibaut , Cordelieres Fabrice P. , Pazour Gregory J.
Published: March 2018

The vertebrate hedgehog pathway is organized in primary cilia, and hedgehog components relocate into or out of cilia during signaling. Defects in intraflagellar transport (IFT) typically disrupt ciliary assembly and attenuate hedgehog signaling. Determining whether IFT drives the movement of hedgehog components is difficult due to the requirement of IFT for building cilia. Unlike most IFT proteins, IFT27 is dispensable for cilia formation but affects hedgehog signaling similarly to other IFTs, allowing us to examine its role in the dynamics of signaling. Activating signaling at points along the pathway in Ift27 mutant cells showed that IFT is extensively involved in the pathway. Similar analysis of Bbs mutant cells showed that BBS proteins participate at many levels of signaling but are not needed to concentrate Gli transcription factors at the ciliary tip. Our analysis showed that smoothened delivery to cilia does not require IFT27, but the role of other IFTs is not known. Using a rapamycin-induced dimerization system to sequester IFT-B proteins at the mitochondria in cells with fully formed cilia did not affect the delivery of Smo to cilia, suggesting that this membrane protein may not require IFT-B for delivery.
Mapping the mammalian ribosome quality control complex interactome using proximity labeling approaches
Authors: Zuzow Nathan , Ghosh Arit , Leonard Marilyn , Liao Jeffrey , Yang Bing , Bennett Eric J.
Published: March 2018

Previous genetic and biochemical studies from Saccharomyces cerevisiae have identified a critical ribosome-associated quality control complex (RQC) that facilitates resolution of stalled ribosomal complexes. While components of the mammalian RQC have been examined in vitro, a systematic characterization of RQC protein interactions in mammalian cells has yet to be described. Here we utilize both proximity-labeling proteomic approaches, BioID and APEX, and traditional affinity-based strategies to both identify interacting proteins of mammalian RQC members and putative substrates for the RQC resident E3 ligase, Ltn1. Surprisingly, validation studies revealed that a subset of substrates are ubiquitylated by Ltn1 in a regulatory manner that does not result in subsequent substrate degradation. We demonstrate that Ltn1 catalyzes the regulatory ubiquitylation of ribosomal protein S6 kinase 1 and 2 (RPS6KA1, RPS6KA3). Further, loss of Ltn1 function results in hyperactivation of RSK1/2 signaling without impacting RSK1/2 protein turnover. These results suggest that Ltn1-mediated RSK1/2 ubiquitylation is inhibitory and establishes a new role for Ltn1 in regulating mitogen-activated kinase signaling via regulatory RSK1/2 ubiquitylation. Taken together, our results suggest that mammalian RQC interactions are difficult to observe and may be more transient than the homologous complex in S. cerevisiae and that Ltn1 has RQC-independent functions.
Network-based integration of multi-omics data for prioritizing cancer genes
Authors: Dimitrakopoulos Christos , Hindupur Sravanth Kumar , Häfliger Luca , Behr Jonas , Montazeri Hesam , Hall Michael N , Beerenwinkel Niko
Published: March 2018

Motivation

Several molecular events are known to be cancer-related, including genomic aberrations, hypermethylation of gene promoter regions and differential expression of microRNAs. These aberration events are very heterogeneous across tumors and it is poorly understood how they affect the molecular makeup of the cell, including the transcriptome and proteome. Protein interaction networks can help decode the functional relationship between aberration events and changes in gene and protein expression.

Results

We developed NetICS (Network-based Integration of Multi-omics Data), a new graph diffusion-based method for prioritizing cancer genes by integrating diverse molecular data types on a directed functional interaction network. NetICS prioritizes genes by their mediator effect, defined as the proximity of the gene to upstream aberration events and to downstream differentially expressed genes and proteins in an interaction network. Genes are prioritized for individual samples separately and integrated using a robust rank aggregation technique. NetICS provides a comprehensive computational framework that can aid in explaining the heterogeneity of aberration events by their functional convergence to common differentially expressed genes and proteins. We demonstrate NetICS’ competitive performance in predicting known cancer genes and in generating robust gene lists using TCGA data from five cancer types.

Availability and implementation

NetICS is available at https://github.com/cbg-ethz/netics.

Supplementary information

Supplementary data are available at Bioinformatics online.
A micro X-ray computed tomography dataset of South African hermit crabs (Crustacea: Decapoda: Anomura: Paguroidea) containing scans of two rare specimens and three recently described species
Authors: Landschoff Jannes , Du Plessis Anton , Griffiths Charles L
Published: March 2018

Background

Along with the conventional deposition of physical types at natural history museums, the deposition of 3-dimensional (3D) image data has been proposed for rare and valuable museum specimens, such as irreplaceable type material.

Findings

Micro computed tomography (μCT) scan data of 5 hermit crab species from South Africa, including rare specimens and type material, depicted main identification characteristics of calcified body parts. However, low-image contrasts, especially in larger (>50 mm total length) specimens, did not allow sufficient 3D reconstructions of weakly calcified and fine characteristics, such as soft tissue of the pleon, mouthparts, gills, and setation. Reconstructions of soft tissue were sometimes possible, depending on individual sample and scanning characteristics. The raw data of seven scans are publicly available for download from the GigaDB repository.

Conclusions

Calcified body parts visualized from μCT data can aid taxonomic validation and provide additional, virtual deposition of rare specimens. The use of a nondestructive, nonstaining μCT approach for taxonomy, reconstructions of soft tissue structures, microscopic spines, and setae depend on species characteristics. Constrained to these limitations, the presented dataset can be used for future morphological studies. However, our virtual specimens will be most valuable to taxonomists who can download a digital avatar for 3D examination. Simultaneously, in the event of physical damage to or loss of the original physical specimen, this dataset serves as a vital insurance policy.