bluuebunny/crossref_metadata_2025 huggingface dataset:
A widefield fluorescence microscope with a linear image sensor for image cytometry of biospecimens: Considerations for image quality optimization
Authors: Hutcheson Joshua A. , Majid Aneeka A. , Powless Amy J. , Muldoon Timothy J.
Published: October 2015

Linear image sensors have been widely used in numerous research and industry applications to provide continuous imaging of moving objects. Here, we present a widefield fluorescence microscope with a linear image sensor used to image translating objects for image cytometry. First, a calibration curve was characterized for a custom microfluidic chamber over a span of volumetric pump rates. Image data were also acquired using 15 μm fluorescent polystyrene spheres on a slide with a motorized translation stage in order to match linear translation speed with line exposure periods to preserve the image aspect ratio. Aspect ratios were then calculated after imaging to ensure quality control of image data. Fluorescent beads were imaged in suspension flowing through the microfluidics chamber being pumped by a mechanical syringe pump at 16 μl min−1 with a line exposure period of 150 μs. The line period was selected to acquire images of fluorescent beads with a 40 dB signal-to-background ratio. A motorized translation stage was then used to transport conventional glass slides of stained cellular biospecimens. Whole blood collected from healthy volunteers was stained with 0.02% (w/v) proflavine hemisulfate was imaged to highlight leukocyte morphology with a 1.56 mm × 1.28 mm field of view (1540 ms total acquisition time). Oral squamous cells were also collected from healthy volunteers and stained with 0.01% (w/v) proflavine hemisulfate to demonstrate quantifiable subcellular features and an average nuclear to cytoplasmic ratio of 0.03 (n = 75), with a resolution of 0.31 μm pixels−1.
Multiresolution persistent homology for excessively large biomolecular datasets
Authors: Xia Kelin , Zhao Zhixiong , Wei Guo-Wei
Published: October 2015

Although persistent homology has emerged as a promising tool for the topological simplification of complex data, it is computationally intractable for large datasets. We introduce multiresolution persistent homology to handle excessively large datasets. We match the resolution with the scale of interest so as to represent large scale datasets with appropriate resolution. We utilize flexibility-rigidity index to access the topological connectivity of the data set and define a rigidity density for the filtration analysis. By appropriately tuning the resolution of the rigidity density, we are able to focus the topological lens on the scale of interest. The proposed multiresolution topological analysis is validated by a hexagonal fractal image which has three distinct scales. We further demonstrate the proposed method for extracting topological fingerprints from DNA molecules. In particular, the topological persistence of a virus capsid with 273 780 atoms is successfully analyzed which would otherwise be inaccessible to the normal point cloud method and unreliable by using coarse-grained multiscale persistent homology. The proposed method has also been successfully applied to the protein domain classification, which is the first time that persistent homology is used for practical protein domain analysis, to our knowledge. The proposed multiresolution topological method has potential applications in arbitrary data sets, such as social networks, biological networks, and graphs.
Fast ion energy distribution from third harmonic radio frequency heating measured with a single crystal diamond detector at the Joint European Torus
Authors: Nocente M. , Cazzaniga C. , Tardocchi M. , Binda F. , Eriksson J. , Giacomelli L. , Muraro A. , Rebai M. , Sharapov S. , Gorini G. ,   JET Contributors
Published: October 2015

Neutron spectroscopy measurements with a single crystal diamond detector have been carried out at JET, for the first time in an experiment aimed at accelerating deuterons to MeV energies with radio frequency heating at the third harmonic. Data are interpreted by means of the expected response function of the detector and are used to extract parameters of the highly non-Maxwellian distribution function generated in this scenario. A comparison with observations using a time of flight and liquid scintillator neutron spectrometers is also presented. The results demonstrate the capability of diamond detectors to contribute to fast ion physics studies at JET and are of more general relevance in view of the application of such detectors for spectroscopy measurements in the neutron camera of next step tokamak devices.
Simultaneous calorimetric and polarization microscopy investigations of light induced changes over phase transitions in a liquid crystal–napthopyran mixture
Authors: Paoloni S. , Mercuri F. , Marinelli M. , Pizzoferrato R. , Zammit U. , Kosa T. , Sukhomlinova L. , Taheri B.
Published: October 2015

We have studied the specific heat and the thermal conductivity in a 4-(n-octyl)-4′-cyanobiphenyl liquid crystal (LC)-photochromic molecules mixture, before, during, and after the photo-activation of the dispersed photochromic molecules, over both the smectic A-nematic and the nematic-isotropic phase transitions. The evaluation of the specific heat has enabled the determination of the changes of the phase transition characteristics induced by the photochromic molecules photoisomerization, while that of the thermal conductivity could be used to monitor the modifications induced in the average LC molecular orientation. The polarization microscopy imaging of the sample texture constituted a valuable support for the interpretation of the obtained thermal conductivity results.
Photogeneration and enhanced charge transport in aligned smectic liquid crystalline organic semiconductor
Authors: Paul Sanjoy , Ellman Brett , Tripathi Suvagata , Twieg Robert J.
Published: October 2015

Liquid crystalline organic semiconductors are emerging candidates for applications in electronic and photonic devices. One of the most attractive aspects of such materials is the potential, in principle, to easily control and manipulate the molecular alignment of the semiconductor over large length scales. Here, we explore the consequences of alignment in a model smectic liquid crystalline semiconductor, and find that the photogeneration efficiency is a strong function of incident polarization in aligned samples. A straightforward theory shows that such behavior is a general feature of aligned materials, regardless of the details of photophysics. Furthermore, we uncover tentative evidence that the mobility of aligned samples is substantially enhanced. Both of these phenomena are of significant technological importance.
Investigation of the validity of Dynamic AcoustoElastic Testing for measuring nonlinear elasticity
Authors: Scalerandi M. , Gliozzi A. S. , Haupert S. , Renaud G. , Ait Ouarabi M. , Boubenider F.
Published: October 2015

Measurement of the dependence of the elastic moduli on the strain, i.e., the characterization of nonlinear elastic properties of solid media, poses intrinsic experimental difficulties. The Dynamic AcoustoElastic Technique has been recently developed as an efficient tool for the determination of the modulus in both compression and tension. The goal of the present paper is to discuss the limitations of the experimental implementation and the interpretation of the measured quantities in terms of nonlinear parameters. For this purpose, simulation results will be presented for both classical and nonclassical nonlinear elastic media.
Unusual dynamic properties of water near the ice-binding plane of hyperactive antifreeze protein
Authors: Kuffel Anna , Czapiewski Dariusz , Zielkiewicz Jan
Published: October 2015

The dynamical properties of solvation water of hyperactive antifreeze protein from Choristoneura fumiferana (CfAFP) are analyzed and discussed in context of its antifreeze activity. The protein comprises of three well-defined planes and one of them binds to the surface of ice. The dynamical properties of solvation water around each of these planes were analyzed separately; the results are compared with the dynamical properties of solvation water of ice around its two crystallographic planes: basal and prism. Three main conclusions are inferred from our investigations. The first one is that the solvation shell of CfAFP does not seem to be particularly far-ranged, at least not beyond what is usually observed for proteins that do not interact with ice. Therefore, it does not appear to us that the antifreeze activity is enhanced by a long-ranged retardation of water mobility. Also the correlation between the collective mobility of water and the collective mobility of protein atoms highly resembles the one measured for the protein that does not interact with ice. Our second conclusion is that the dynamical properties of solvation water of CfAFP are non-uniform. The dynamics of solvation water of ice-binding plane is, in some respects, different from the dynamics of solvation water of the two remaining planes. The feature that distinguishes the dynamics of solvation water of the three planes is the activation energy of diffusion process. The third conclusion is that—from the three analyzed solvation shells of CfAFP—the dynamical properties of solvation water of the ice-binding plane resemble the most the properties of solvation water of ice; note, however, that these properties still clearly differ from the dynamic properties of solvation water of ice.
Microwave spectra and structure of the cyclopropanecarboxylic acid-formic acid dimer
Authors: Pejlovas Aaron M. , Lin Wei , Kukolich Stephen G.
Published: October 2015

The rotational spectrum of the cyclopropanecarboxylic acid–formic acid doubly hydrogen bonded dimer has been measured in the 4-11 GHz region using a Flygare-Balle type pulsed-beam Fourier transform microwave spectrometer. Rotational transitions were measured for the parent, four unique singly substituted 13C isotopologues, and a singly deuterated isotopologue. Splittings due to a possible concerted double proton tunneling motion were not observed. Rotational constants (A, B, and C) and centrifugal distortion constants (DJ and DJK) were determined from the measured transitions for the dimer. The values of the rotational (in MHz) and centrifugal distortion constants (in kHz) for the parent isotopologue are A = 4045.4193(16), B = 740.583 80(14), C = 658.567 60(23), DJ = 0.0499(16), and DJK = 0.108(14). A partial gas phase structure of the dimer was derived from the rotational constants of the measured isotopologues, previous structural work on each monomer units and results of the calculations.
Comment on “Open-circuit and doping transients of Cu(In,Ga)Se2 solar cells with varying Ga content” [J. Appl. Phys. 117, 055704 (2015)]
Authors: Maciaszek M. , Zabierowski P.
Published: October 2015

Recently, Obereigner et al. analyzed theoretically doping transients in Cu(In,Ga)Se2. An approximate solution of a differential equation describing dynamics of the fraction of metastable complexes (VSe − VCu) in the acceptor configuration fA(t) was given. In the present comment, we show that presented solution is based on erroneous assumptions and we provide a correct expression for fA(t).
A single-cell scraper based on an atomic force microscope for detaching a living cell from a substrate
Authors: Iwata Futoshi , Adachi Makoto , Hashimoto Shigetaka
Published: October 2015

We describe an atomic force microscope (AFM) manipulator that can detach a single, living adhesion cell from its substrate without compromising the cell's viability. The micrometer-scale cell scraper designed for this purpose was fabricated from an AFM micro cantilever using focused ion beam milling. The homemade AFM equipped with the scraper was compact and standalone and could be mounted on a sample stage of an inverted optical microscope. It was possible to move the scraper using selectable modes of operation, either a manual mode with a haptic device or a computer-controlled mode. The viability of the scraped single cells was evaluated using a fluorescence dye of calcein-acetoxymethl ester. Single cells detached from the substrate were collected by aspiration into a micropipette capillary glass using an electro-osmotic pump. As a demonstration, single HeLa cells were selectively detached from the substrate and collected by the micropipette. It was possible to recultivate HeLa cells from the single cells collected using the system.
High reactivity of nanosized niobium oxide cluster cations in methane activation: A comparison with vanadium oxides
Authors: Ding Xun-Lei , Wang Dan , Wu Xiao-Nan , Li Zi-Yu , Zhao Yan-Xia , He Sheng-Gui
Published: October 2015

The reactions between methane and niobium oxide cluster cations were studied and compared to those employing vanadium oxides. Hydrogen atom abstraction (HAA) reactions were identified over stoichiometric (Nb2O5)N+ clusters for N as large as 14 with a time-of-flight mass spectrometer. The reactivity of (Nb2O5)N+ clusters decreases as the N increases, and it is higher than that of (V 2O5)N+ for N ≥ 4. Theoretical studies were conducted on (Nb2O5)N+ (N = 2–6) by density functional calculations. HAA reactions on these clusters are all favorable thermodynamically and kinetically. The difference of the reactivity with respect to the cluster size and metal type (Nb vs V) was attributed to thermodynamics, kinetics, the electron capture ability, and the distribution of the unpaired spin density. Nanosized Nb oxide clusters show higher HAA reactivity than V oxides, indicating that niobia may serve as promising catalysts for practical methane conversion.
Versatile setup for optical spectroscopy under high pressure and low temperature
Authors: Tran Michaël K. , Levallois Julien , Akrap Ana , Teyssier Jérémie , Kuzmenko Alexey B. , Lévy-Bertrand Florence , Tediosi Riccardo , Brandt Mehdi , Lerch Philippe , van der Marel Dirk
Published: October 2015

We present an optical setup for spectroscopic measurements in the infrared and of Raman shift under high pressure and at low temperature. Using a membrane-driven diamond anvil cell, the pressure can be tuned in situ up to 20 GPa and the temperatures ranges from room temperature down to 18 K in transmission mode and 13 K in reflection mode. In transmission, the setup is entirely working under vacuum to reduce the water absorption features and obtain a higher spectral stability. Since the infrared throughput obtained with a thermal source is limited, the use of a synchrotron source allowed to enhance the performance, as illustrated with results obtained with various materials. The analysis of the reflectivity is adapted so that it benefits from ambient pressure data and produces quantitative optical conductivity curves that can be easily compared to the results at ambient pressure.
Effect of in-material losses on terahertz absorption, transmission, and reflection in photonic crystals made of polar dielectrics
Authors: Serebryannikov Andriy E. , Nojima S. , Alici K. B. , Ozbay Ekmel
Published: October 2015

The effect of the material absorption factor on terahertz absorption (A), transmittance (T), and reflectance (R) for slabs of PhC that comprise rods made of GaAs, a polar dielectric, is studied. The main goal was to illustrate how critical a choice of the absorption factor for simulations is and to indicate the importance of the possible modification of the absorption ability by using either active or lossy impurities. The spectra of A, T, and R are strongly sensitive to the location of the polaritonic gap with respect to the photonic pass and stop bands connected with periodicity that enables the efficient combination of the effects of material and structural parameters. It will be shown that the spectra can strongly depend on the utilized value of the material absorption factor. In particular, both narrow and wide absorption bands may appear owing to a variation of the material parameters with a frequency in the vicinity of the polaritonic gap. The latter are often achieved at wideband suppression of transmission, so that an ultra-wide stop band can appear as a result of adjustment of the stop bands having different origin. The results obtained at simultaneous variation of the absorption factor and frequency, and angle of incidence and frequency, indicate the possibility of the existence of wide ranges of tolerance, in which the basic features do remain. This allows for mitigating the accuracy requirements for the absorption factor in simulations and promises the efficient absorption of nonmonochromatic waves and beams with a wide angular spectrum. Suppression of narrowband effects in transmission is demonstrated at rather large values of the absorption factor, when they appear due to either the defect modes related to structural defects or dispersion inspired variations of the material parameters in the vicinity of the polaritonic gap. Comparison with auxiliary structures helps one to detect the common features and differences of homogeneous slabs and slabs of a PhC, which are made of GaAs.
Communication: Cosolvency and cononsolvency explained in terms of a Flory-Huggins type theory
Authors: Dudowicz Jacek , Freed Karl F. , Douglas Jack F.
Published: October 2015

Standard Flory-Huggins (FH) theory is utilized to describe the enigmatic cosolvency and cononsolvency phenomena for systems of polymers dissolved in mixed solvents. In particular, phase boundaries (specifically upper critical solution temperature spinodals) are calculated for solutions of homopolymers B in pure solvents and in binary mixtures of small molecule liquids A and C. The miscibility (or immiscibility) patterns for the ternary systems are classified in terms of the FH binary interaction parameters {χαβ} and the ratio r = ϕA/ϕC of the concentrations ϕA and ϕC of the two solvents. The trends in miscibility are compared to those observed for blends of random copolymers (AxC1−x) with homopolymers (B) and to those deduced for A/B/C solutions of polymers B in liquid mixtures of small molecules A and C that associate into polymeric clusters {ApCq}i, (i = 1, 2, …, ∞). Although the classic FH theory is able to explain cosolvency and cononsolvency phenomena, the theory does not include a consideration of the mutual association of the solvent molecules and the competitive association between the solvent molecules and the polymer. These interactions can be incorporated in refinements of the FH theory, and the present paper provides a foundation for such extensions for modeling the rich thermodynamics of polymers in mixed solvents.
On the role of HNS and HSN as light-sensitive NO-donors for delivery in biological media
Authors: Trabelsi Tarek , Linguerri Roberto , Ben Yaghlane Saida , Jaidane Nejm-Eddine , Mogren Al-Mogren Muneerah , Francisco Joseph S. , Hochlaf Majdi
Published: October 2015

Results are presented that suggest that thiazyl hydride (HSN)/thionitrosyl hydride (sulfimide, HNS) can be used as light-sensitive compounds for NO-delivery in biological media, as well as markers for the possible detection of intermediates in nitrites + H2S reactions at the cellular level. They are expected to be more efficient than the HNO/HON isovalent species and hence they should be considered instead. A set of characteristic spectroscopic features are identified that could aid in the possible detection of these species in the gas phase or in biological environments. The possibility of intramolecular dynamical processes involving excited states that are capable of interconverting HNS and its isomeric form HSN is examined.
Depth-dependent phase change in Gd2O3 epitaxial layers under ion irradiation
Authors: Mejai N. , Debelle A. , Thomé L. , Sattonnay G. , Gosset D. , Boulle A. , Dargis R. , Clark A.
Published: October 2015

Epitaxial Gd2O3 thin layers with the cubic structure were irradiated with 4-MeV Au2+ ions in the 1013–1015 cm−2 fluence range. X-ray diffraction indicates that ion irradiation induces a cubic to monoclinic phase change. Strikingly, although the energy-deposition profile of the Au2+ ions is constant over the layer thickness, this phase transformation is depth-dependent, as revealed by a combined X-ray diffraction and ion channeling analysis. In fact, the transition initiates very close to the surface and propagates inwards, which can be explained by an assisted migration process of irradiation-induced defects. This result is promising for developing a method to control the thickness of the rare-earth oxide crystalline phases.
Microscopically crumpled indium-tin-oxide thin films as compliant electrodes with tunable transmittance
Authors: Ong Hui-Yng , Shrestha Milan , Lau Gih-Keong
Published: October 2015

Indium-tin-oxide (ITO) thin films are perceived to be stiff and brittle. This letter reports that crumpled ITO thin films on adhesive poly-acrylate dielectric elastomer can make compliant electrodes, sustaining compression of up to 25% × 25% equi-biaxial strain and unfolding. Its optical transmittance reduces with crumpling, but restored with unfolding. A dielectric elastomer actuator (DEA) using the 14.2% × 14.2% initially crumpled ITO thin-film electrodes is electrically activated to produce a 37% areal strain. Such electric unfolding turns the translucent DEA to be transparent, with transmittance increased from 39.14% to 52.08%. This transmittance tunability promises to make a low-cost smart privacy window.
Thermal management in MoS2 based integrated device using near-field radiation
Authors: Peng Jiebin , Zhang Gang , Li Baowen
Published: October 2015

Recently, wafer-scale growth of monolayer MoS2 films with spatial homogeneity is realized on SiO2 substrate. Together with the latest reported high mobility, MoS2 based integrated electronic devices are expected to be fabricated in the near future. Owing to the low lattice thermal conductivity in monolayer MoS2, and the increased transistor density accompanied with the increased power density, heat dissipation will become a crucial issue for these integrated devices. In this letter, using the formalism of fluctuation electrodynamics, we explored the near-field radiative heat transfer from a monolayer MoS2 to graphene. We demonstrate that in resonance, the maximum heat transfer via near-field radiation between MoS2 and graphene can be ten times higher than the in-plane lattice thermal conduction for MoS2 sheet. Therefore, an efficient thermal management strategy for MoS2 integrated device is proposed: Graphene sheet is brought into close proximity, 10–20 nm from MoS2 device; heat energy transfer from MoS2 to graphene via near-field radiation; this amount of heat energy then be conducted to contact due to ultra-high lattice thermal conductivity of graphene. Our work sheds light for developing cooling strategy for nano devices constructing with low thermal conductivity materials.
Physical mechanisms of copper-copper wafer bonding
Authors: Rebhan B. , Hingerl K.
Published: October 2015

The study of the physical mechanisms driving Cu-Cu wafer bonding allowed for reducing the bonding temperatures below 200 °C. Metal thermo-compression Cu-Cu wafer bonding results obtained at such low temperatures are very encouraging and suggest that the process is possible even at room temperature if some boundary conditions are fulfilled. Sputtered (PVD) and electroplated Cu thin layers were investigated, and the analysis of both metallization techniques demonstrated the importance of decreasing Cu surface roughness. For an equal surface roughness, the bonding temperature of PVD Cu wafers could be even further reduced due to the favorable microstructure. Their smaller grain size enhances the length of the grain boundaries (observed on the surface prior bonding), acting as efficient mass transfer channels across the interface, and hence the grains are able to grow over the initial bonding interface. Due to the higher concentration of random high-angle grain boundaries, this effect is intensified. The model presented is explaining the microstructural changes based on atomic migration, taking into account that the reduction of the grain boundary area is the major driving force to reduce the Gibbs free energy, and predicts the subsequent microstructure evolution (grain growth) during thermal annealing.
A heat-switch-based electrocaloric cooler
Authors: Wang Y. D. , Smullin S. J. , Sheridan M. J. , Wang Q. , Eldershaw C. , Schwartz D. E.
Published: October 2015

A heat-switch-based electrocaloric cooler is reported in this letter. The device consists of two silicon heat switches and an electrocaloric module based on BaTO3 multilayer capacitors (MLCs). To operate the cooler, the heat switches are actuated synchronously with the application of electric fields across the MLCs. Heat flux versus temperature lift is fully characterized. With an electric field strength of 277 kV/cm, the system achieves a maximum heat flux of 36 mW and maximum temperature lift of greater than 0.3 °C, close to the expected MLC adiabatic temperature change of 0.5 °C. The cooler is shown to work reliably over thousands of actuation cycles.
Demonstration of a directional sonic prism in two dimensions using an air-acoustic leaky wave antenna
Authors: Naify Christina J. , Guild Matthew D. , Rohde Charles A. , Calvo David C. , Orris Gregory J.
Published: October 2015

Analysis and experimental demonstration of a two-dimensional acoustic leaky wave antenna is presented for use in air. The antenna is comprised of a two-dimensional waveguide patterned with radiating acoustic shunts. When excited using a single acoustic source within the waveguide, the antenna acts as a sonic prism that exhibits frequency steering. This design allows for control of acoustic steering angle using only a single source transducer and a patterned aperture. Aperture design was determined using transmission line analysis and finite element methods. The designed antenna was fabricated and the steering angle measured. The performance of the measured aperture was within 9% of predicted angle magnitudes over all examined frequencies.
On-chip DNA preconcentration in different media conductivities by electrodeless dielectrophoresis
Authors: Li Shunbo , Ye Ziran , Hui Yu Sanna , Gao Yibo , Jiang Yusheng , Wen Weijia
Published: October 2015

Electrodeless dielectrophoresis is the best choice to achieve preconcentration of nanoparticles and biomolecules due to its simple, robust, and easy implementation. We designed a simple chip with microchannels and nano-slits in between and then studied the trapping of DNA in high conductive medium and low conductive medium, corresponding to positive and negative dielectrophoresis (DEP), respectively. It is very important to investigate the trapping in media with different conductivities since one always has to deal with the sample solutions with different conductivities. The trapping process was analyzed by the fluorescent intensity changes. The results showed that DNA could be trapped at the nano-slit in both high and low conductive media in a lower electric field strength (10 V/cm) compared to the existing methods. This is a significant improvement to suppress the Joule heating effect in DEP related experiments. Our work may give insight to researchers for DNA trapping by a simple and low cost device in the Lab-on-a-Chip system.
Effects of quantum well growth temperature on the recombination efficiency of InGaN/GaN multiple quantum wells that emit in the green and blue spectral regions
Authors: Hammersley S. , Kappers M. J. , Massabuau F. C.-P. , Sahonta S.-L. , Dawson P. , Oliver R. A. , Humphreys C. J.
Published: October 2015

InGaN-based light emitting diodes and multiple quantum wells designed to emit in the green spectral region exhibit, in general, lower internal quantum efficiencies than their blue-emitting counter parts, a phenomenon referred to as the “green gap.” One of the main differences between green-emitting and blue-emitting samples is that the quantum well growth temperature is lower for structures designed to emit at longer wavelengths, in order to reduce the effects of In desorption. In this paper, we report on the impact of the quantum well growth temperature on the optical properties of InGaN/GaN multiple quantum wells designed to emit at 460 nm and 530 nm. It was found that for both sets of samples increasing the temperature at which the InGaN quantum well was grown, while maintaining the same indium composition, led to an increase in the internal quantum efficiency measured at 300 K. These increases in internal quantum efficiency are shown to be due reductions in the non-radiative recombination rate which we attribute to reductions in point defect incorporation.
Automatic sequential fluid handling with multilayer microfluidic sample isolated pumping
Authors: Liu Jixiao , Fu Hai , Yang Tianhang , Li Songjing
Published: October 2015

To sequentially handle fluids is of great significance in quantitative biology, analytical chemistry, and bioassays. However, the technological options are limited when building such microfluidic sequential processing systems, and one of the encountered challenges is the need for reliable, efficient, and mass-production available microfluidic pumping methods. Herein, we present a bubble-free and pumping-control unified liquid handling method that is compatible with large-scale manufacture, termed multilayer microfluidic sample isolated pumping (mμSIP). The core part of the mμSIP is the selective permeable membrane that isolates the fluidic layer from the pneumatic layer. The air diffusion from the fluidic channel network into the degassing pneumatic channel network leads to fluidic channel pressure variation, which further results in consistent bubble-free liquid pumping into the channels and the dead-end chambers. We characterize the mμSIP by comparing the fluidic actuation processes with different parameters and a flow rate range of 0.013 μl/s to 0.097 μl/s is observed in the experiments. As the proof of concept, we demonstrate an automatic sequential fluid handling system aiming at digital assays and immunoassays, which further proves the unified pumping-control and suggests that the mμSIP is suitable for functional microfluidic assays with minimal operations. We believe that the mμSIP technology and demonstrated automatic sequential fluid handling system would enrich the microfluidic toolbox and benefit further inventions.
Modeling of chemotactic steering of bacteria-based microrobot using a population-scale approach
Authors: Cho Sunghoon , Choi Young Jin , Zheng Shaohui , Han Jiwon , Ko Seong Young , Park Jong-Oh , Park Sukho
Published: October 2015

The bacteria-based microrobot (Bacteriobot) is one of the most effective vehicles for drug delivery systems. The bacteriobot consists of a microbead containing therapeutic drugs and bacteria as a sensor and an actuator that can target and guide the bacteriobot to its destination. Many researchers are developing bacteria-based microrobots and establishing the model. In spite of these efforts, a motility model for bacteriobots steered by chemotaxis remains elusive. Because bacterial movement is random and should be described using a stochastic model, bacterial response to the chemo-attractant is difficult to anticipate. In this research, we used a population-scale approach to overcome the main obstacle to the stochastic motion of single bacterium. Also known as Keller-Segel's equation in chemotaxis research, the population-scale approach is not new. It is a well-designed model derived from transport theory and adaptable to any chemotaxis experiment. In addition, we have considered the self-propelled Brownian motion of the bacteriobot in order to represent its stochastic properties. From this perspective, we have proposed a new numerical modelling method combining chemotaxis and Brownian motion to create a bacteriobot model steered by chemotaxis. To obtain modeling parameters, we executed motility analyses of microbeads and bacteriobots without chemotactic steering as well as chemotactic steering analysis of the bacteriobots. The resulting proposed model shows sound agreement with experimental data with a confidence level <0.01.
Al and Ge simultaneous oxidation using neutral beam post-oxidation for formation of gate stack structures
Authors: Ohno Takeo , Nakayama Daiki , Samukawa Seiji
Published: October 2015

To obtain a high-quality Germanium (Ge) metal–oxide–semiconductor structure, a Ge gate stacked structure was fabricated using neutral beam post-oxidation. After deposition of a 1-nm-thick Al metal film on a Ge substrate, simultaneous oxidation of Al and Ge was carried out at 300 °C, and a Ge oxide film with 29% GeO2 content was obtained by controlling the acceleration bias power of the neutral oxygen beam. In addition, the fabricated AlOx/GeOx/Ge structure achieved a low interface state density of less than 1 × 1011 cm−2 eV−1 near the midgap.
The morphological and functional development of the stria vascularis in miniature pigs
Authors: Guo Weiwei , Yi Haijin , Yan Zhang , Ren Lili , Chen Lei , Zhao Li Dong , Ning Yu , He David Z. Z. , Yang Shi-Ming
Published: October 2015

The purpose of this study was to examine the morphological and functional development of the lateral wall of the scala media of the cochlea in miniature pigs; light and transmission electron microscopy and electrophysiology were used for this purpose. We showed that the lateral wall of the scala media of the cochlea appears at embryonic Day 21 (E21) when the cochlear duct begins to form. From E28 to E49, the lateral wall can be distinguished according to its position along the cochlea. At E56, cells in the lateral wall begin to differentiate into three different types. At E70, three cell types, marginal, intermediate and basal, can be clearly distinguished. At E91, the stria vascularis is adult-like and the organ of Corti is also morphologically mature. The average endocochlear potential measured from the second turn of the cochlea (at E98, postnatal Day 1 (P1), P13 and P30) was 71.4 ± 2.5 (n = 7), 78.8 ± 1.5 (n = 10), 77.3 ± 2.3 (n = 10) and 78.0 ± 2.1 mV (n = 10), respectively. Our results suggest that in miniature pigs the stria vascularis develops during the embryonic period, concurrent with maturation of the organ of Corti. The magnitude of the endocochlear potential reached its mature level when the stria vascularis was morphologically adult-like at E98. These findings provide a morphological and functional basis for future animal studies using the miniature pig model concerning the pathogenesis of various inner-ear diseases.
X-ray microtomography using correlation of near-field speckles for material characterization
Authors: Zanette Irene , Zdora Marie-Christine , Zhou Tunhe , Burvall Anna , Larsson Daniel H. , Thibault Pierre , Hertz Hans M. , Pfeiffer Franz
Published: October 2015

Significance

We present X-ray speckle tracking tomography, a simple, robust, and versatile method to obtain simultaneously phase and absorption tomograms of the sample at the micrometer scale with a laboratory X-ray source. The method is based on correlation of near-field speckles and yields quantitative measurements of the full X-ray refractive index of the object with high sensitivity. X-ray speckle tracking tomography broadens the capabilities of X-ray imaging at laboratory sources with strong potential in materials and life sciences.
STIM1–Ca
2+
signaling modulates automaticity of the mouse sinoatrial node
Authors: Zhang Hengtao , Sun Albert Y. , Kim Jong J. , Graham Victoria , Finch Elizabeth A. , Nepliouev Igor , Zhao Guiling , Li Tianyu , Lederer W. J. , Stiber Jonathan A. , Pitt Geoffrey S. , Bursac Nenad , Rosenberg Paul B.
Published: October 2015

Significance

Each heartbeat originates in the sinoatrial node (SAN), a collection of specialized cardiomyocytes (SANCs), which exhibit rhythmic action potentials and spontaneous Ca
2+
transients. We have found that the Ca
2+
sensor protein stromal interaction molecule 1 (STIM1) is enriched in the SANCs. Here we show that STIM1 Ca
2+
signaling is important in SANCs to maintain the Ca
2+
content of intracellular Ca
2+
stores and that this contributes to maintaining the regular sinus rhythm of the heart.
Fibonacci family of dynamical universality classes
Authors: Popkov Vladislav , Schadschneider Andreas , Schmidt Johannes , Schütz Gunter M.
Published: October 2015

Significance

Universality is a well-established central concept of equilibrium physics. It asserts that, especially near phase transitions, the properties of a physical system do not depend on its details such as the precise form of interactions. Far from equilibrium, such universality has also been observed, but, in contrast to equilibrium, a deeper understanding of its underlying principles is still lacking. We show that the two best-known examples of nonequilibrium universality classes, the diffusive and Kardar−Parisi−Zhang classes, are only part of an infinite discrete family. The members of this family can be identified by their dynamical exponent, which, surprisingly, can be expressed by a Kepler ratio of Fibonacci numbers. This strongly indicates the existence of a simpler underlying mechanism that determines the different classes.
Extreme events in computational turbulence
Authors: Yeung P. K. , Zhai X. M. , Sreenivasan Katepalli R.
Published: October 2015

Significance

In the last decade or so, massive computations of turbulence performed by solving the exact equations of hydrodynamic turbulence have provided new quantitative data and enhanced our understanding. This paper presents results from the largest such computations, to date, devoted to the study of small scales. We focus on “extreme events” in energy dissipation and squared vorticity (enstrophy). For the Reynolds numbers of these simulations, events as large as

10

5

times the mean value are observed, albeit rarely. The structure of these extreme events is quite different from that believed previously. The major theme of this and related work is that huge fluctuations exist in hydrodynamic turbulence and that they have basic consequences to turbulence (as is the case in other nonlinear fields).
A bilingual child’s multimodal path into negation
Authors: Benazzo Sandra , Morgenstern Aliyah
Published: October 2015

The study of the expression of negation in longitudinal adult-child data is a privileged locus for a multimodal approach to language acquisition. In the case of bilingual language acquisition, the necessity to enter two languages at once might have an influence on the management of the visual-gestural and the auditory modalities. In order to tackle these issues, we analyze the longitudinal data of Antoine, a bilingual French/Italian child recorded separately once a month for an hour with his Italian mother and with his French father between the ages of 1;5 and 3;5.

Our analyses of all his multimodal utterances with negations show that Antoine has created efficient transitional systems during his developmental path both by combining modalities and by mixing his two native languages. The visual-gestural modality is a stable resource to rely on in all the types of linguistic environments Antoine experiences. His bilingual environment could be connected to the creation of his mixed verbal productions also addressed to both French speaking and Italian speaking interlocutors. Those two transitory creative systems are efficient elements of his communicative repertoire during an important period of his language development. Gesture might therefore have a compensatory function for that little boy. It is a wonderful resource to communicate efficiently in his specific environment during his multimodal, multilingual entry into language.
The influence of iconic and arbitrary gestures on novel word learning in children with and without SLI
Authors: Lüke Carina , Ritterfeld Ute
Published: October 2015

Two experiments were conducted to investigate the role of gestures on novel word learning in preschoolers. In Study 1, 20 children at the average age of 4;9 years were given novel words under 3 conditions: with support of iconic gestures; arbitrary gestures; no gestures, exemplifying a within-subject design. Results indicate scaffolding effects of both types of gestures in comparison to the control condition. No indication of gesture type effects could be observed even in children who were old enough to understand the iconicity of iconic gestures. Study 2 was implemented to further test the scaffolding effect of gestures vs. no gestures in children with SLI (n = 20) — but this time only iconic gestures were used. A between-subjects design was followed, using matched groups. Slow mapping was observed in addition to fast mapping within a 5-week-intervention period. Results confirm the scaffolding effect of iconic gestures on slow mapping in the clinical sample.
Unconfirmed peers and spinelessness
Authors: Sherman Ben
Published: September 2015

The Equal Weight View holds that, when we discover we disagree with an epistemic peer, we should give our peer’s judgment as much weight as our own. But how should we respond when we cannot tell whether those who disagree with us are our epistemic peers? I argue for a position I will call the Earn-a-Spine View. According to this view, parties to a disagreement can remain confident, at least in some situations, by finding justifiable reasons to think their opponents are less credible than themselves, even if those reasons are justifiable only because they lack information about their opponents.
Experiences with bilingual publishing: surveys of authors and editors
Authors: BARTHOLOMÄUS Elke , GOLDBECK‐WOOD Sandy , SEWERING Meike , BAETHGE Christopher
Published: September 2015

Bilingual publishing has become a strategy employed by journals from the non‐Anglophone world to gain wider recognition. Beyond anecdotal evidence, however, there are no published accounts of the experiences of editors and authors of bilingual journals with the process of bilingual publication. It is also unclear how authors writing in bilingual journals judge the quality of the translations and whether they consider this sort of publishing as beneficial for their aims. Consequently, we carried out two surveys: one among editors of bilingual journals and one anonymous survey among authors and translators of articles published in Deutsches Ärzteblatt International, the bilingual journal of the German Medical Association. Eight of nine journals as well as 233 of 353 authors and 4 of 6 translators took part. Most journals reported that bilingual publication helped in becoming indexed in important databases (e.g. Medline), receiving or improving an Impact Factor, and in attracting authors. All journals plan to continue publishing bilingually. Authors were ‘satisfied’ (40.8%) or ‘very satisfied’ (57.8%) with translations. Almost all (96.7%) were in favour of bilingual publication of their work. They did not view an English translation as an obstacle to another related English language paper. Translators highlighted challenges relating to specialized terminology and to terms specific to the regional healthcare system.
Quadratic equations in hyperbolic groups are NP-complete
Authors: Kharlampovich Olga , Mohajeri Atefeh , Taam Alexander , Vdovina Alina
Published: October 2015

We prove that in a torsion-free hyperbolic group

Γ
\Gamma

, the length of the value of each variable in a minimal solution of a quadratic equation

Q
=
1

Q=1

is bounded by

N

|

Q

|

3

N|Q|^3

for an orientable equation, and by

N

|

Q

|

4

N|Q|^{4}

for a non-orientable equation, where

|

Q

|

|Q|

is the length of the equation and the constant

N
N

can be computed. We show that the problem, whether a quadratic equation in

Γ
\Gamma

has a solution, is in NP, and that there is a PSpace algorithm for solving arbitrary equations in

Γ
\Gamma

. If additionally

Γ
\Gamma

is non-cyclic, then this problem (of deciding existence of a solution) is NP-complete. We also give a slightly larger bound for minimal solutions of quadratic equations in a toral relatively hyperbolic group.
PP2A/B56 and GSK3/Ras suppress PKB activity duringDictyosteliumchemotaxis
Authors: Rodriguez Pino Marbelys , Castillo Boris , Kim Bohye , Kim Lou W.
Published: October 2015

We have previously shown that the Dictyostelium protein phosphatase 2A regulatory subunit B56, encoded by psrA, modulates Dictyostelium cell differentiation through negatively affecting glycogen synthase kinase 3 (GSK3) function. Our follow-up research uncovered that B56 preferentially associated with GDP forms of RasC and RasD, but not with RasG in vitro, and psrA−cells displayed inefficient activation of multiple Ras species, decreased random motility, and inefficient chemotaxis toward cAMP and folic acid gradient. Surprisingly, psrA−cells displayed aberrantly high basal and poststimulus phosphorylation of Dictyostelium protein kinase B (PKB) kinase family member PKBR1 and PKB substrates. Expression of constitutively active Ras mutants or inhibition of GSK3 in psrA−cells increased activities of both PKBR1 and PKBA, but only the PKBR1 activity was increased in wild-type cells under the equivalent conditions, indicating that either B56- or GSK3-mediated suppressive mechanism is sufficient to maintain low PKBA activity, but both mechanisms are necessary for suppressing PKBR1. Finally, cells lacking RasD or RasC displayed normal PKBR1 regulation under GSK3-inhibiting conditions, indicating that RasC or RasD proteins are essential for GSK3-mediated PKBR1 inhibition. In summary, B56 constitutes inhibitory circuits for PKBA and PKBR1 and thus heavily affects Dictyostelium chemotaxis.
Spontaneous and electric field–controlled front–rear polarization of human keratinocytes
Authors: Saltukoglu Deniz , Grünewald Julian , Strohmeyer Nico , Bensch Robert , Ulbrich Maximilian H. , Ronneberger Olaf , Simons Matias
Published: October 2015

It has long been known that electrical fields (EFs) are able to influence the direction of migrating cells, a process commonly referred to as electrotaxis or galvanotaxis. Most studies have focused on migrating cells equipped with an existing polarity before EF application, making it difficult to delineate EF-specific pathways. Here we study the initial events in front–rear organization of spreading keratinocytes to dissect the molecular requirements for random and EF-controlled polarization. We find that Arp2/3-dependent protrusive forces and Rac1/Cdc42 activity were generally required for both forms of polarization but were dispensable for controlling the direction of EF-controlled polarization. By contrast, we found a crucial role for extracellular pH as well as G protein coupled–receptor (GPCR) or purinergic signaling in the control of directionality. The normal direction of polarization toward the cathode was reverted by lowering extracellular pH. Polarization toward the anode was also seen at neutral pH when GPCR or purinergic signaling was inhibited. However, the stepwise increase of extracellular pH in this scenario led to restoration of cathodal polarization. Overall our work puts forward a model in which the EF uses distinct polarization pathways. The cathodal pathway involves GPCR/purinergic signaling and is dominant over the anodal pathway at neutral pH.