bluuebunny/crossref_metadata_2025 huggingface dataset:
A novel hybrid nanofibrous strategy to target progenitor cells for cost-effective in situ angiogenesis
Authors: Sachot N. , Castaño O. , Oliveira H. , Martí-Muñoz J. , Roguska A. , Amedee J. , Lewandowska M. , Planell J. A. , Engel E.
Published: September 2016

Ti-doped calcium phosphate ormoglasses combined with biodegradable PLA promote an efficient and low-cost angiogenesis by the generation of high Ca2+concentrated interfaces that induce a high yield of tubulogenesis, with the gain in interface–cell interaction and instructivity.
A bio-inspired cellulose nanocrystal-based nanocomposite photonic film with hyper-reflection and humidity-responsive actuator properties
Authors: Wu Tianhang , Li Jiada , Li Juntao , Ye Simin , Wei Jie , Guo Jinbao
Published: September 2016

The hyper-reflection and humidity-responsive behavior of a bio-inspired cellulose nanocrystal-based nanocomposite photonic film are described.
SS resonance analysis of complex power system incorporating wind power
Authors: Shi Li‐Bao , Su Jun‐Lin , Yao Liang‐Zhong
Published: September 2016

This study aims to conduct the sub‐synchronous (SS) resonance analysis of a multi‐machine power system incorporating doubly fed induction generator (DFIG)‐ or permanent magnetic synchronous generator (PMSG)‐based wind farm. The linearised equations involving the dynamics of steam turbine generator, wind farm, shunt capacitor, transmission line, and load are derived, and the detailed state matrix formation process pertinent to each component is presented. Taking the IEEE 16‐machine‐68‐bus test system as example, the eigenvalue analysis along with participation factor is applied to investigate the impacts of the series compensation level of transmission line on the modal frequencies and damping ratios of two groups of oscillatory modes of interest: namely, the SS mode of the series‐compensated transmission line and the shaft modes of the studied steam turbine generator before and after one of the un‐studied steam turbine generators is replaced by the DFIG‐ or PMSG‐based wind farm. Some useful conclusions and comments are drawn.
Multiple absolute negative mobilities
Authors: Ruyin Chen , Wanli Pan , Jianqiang Zhang , Linru Nie
Published: September 2016

In this paper, we investigate transport of an inertial particle in a spatially symmetric potential and subjected to two harmonic signals with different frequencies in both deterministic and stochastic cases. Numerical results indicate that: (i) In the deterministic case, the two harmonic signals can induce many (up to six) segments of negative slopes in the curve of mean velocity vs. external constant force, i.e., a multiple absolute negative mobilities (ANMs) effect. But the occurrence of the effect depends on their frequencies and amplitudes. (ii) For the stochastic case, the multiple ANMs relay on stable index and symmetry parameter of the Lévy noise. In the case of symmetric noise, appropriate stable index makes the multiple ANMs be the strongest. Our further investigations indicate that an indispensable condition for the multiple ANMs to occur in the system is the temporal symmetry breaking by one multiplicative periodic signal and one additive periodic signal.
Transition and post-transition metal ions in borate glasses: Borate ligand speciation, cluster formation, and their effect on glass transition and mechanical properties
Authors: Möncke D. , Kamitsos E. I. , Palles D. , Limbach R. , Winterstein-Beckmann A. , Honma T. , Yao Z. , Rouxel T. , Wondraczek L.
Published: September 2016

A series of transition and post-transition metal ion (Mn, Cu, Zn, Pb, Bi) binary borate glasses was studied with special consideration of the cations impact on the borate structure, the cations cross-linking capacity, and more generally, structure-property correlations. Infrared (IR) and Raman spectroscopies were used for the structural characterization. These complementary techniques are sensitive to the short-range order as in the differentiation of tetrahedral and trigonal borate units or regarding the number of non-bridging oxygen ions per unit. Moreover, vibrational spectroscopy is also sensitive to the intermediate-range order and to the presence of superstructural units, such as rings and chains, or the combination of rings. In order to clarify band assignments for the various borate entities, examples are given from pure vitreous B2O3 to meta-, pyro-, ortho-, and even overmodified borate glass compositions. For binary metaborate glasses, the impact of the modifier cation on the borate speciation is shown. High field strength cations such as Zn2+ enhance the disproportionation of metaborate to polyborate and pyroborate units. Pb2+ and Bi3+ induce cluster formation, resulting in PbOn- and BiOn-pseudophases. Both lead and bismuth borate glasses show also a tendency to stabilize very large superstructural units in the form of diborate polyanions. Far-IR spectra reflect on the bonding states of modifier cations in glasses. The frequency of the measured cation-site vibration band was used to obtain the average force constant for the metal-oxygen bonding, FM–O. A linear correlation between glass transition temperature (Tg) and FM–O was shown for the metaborate glass series. The mechanical properties of the glasses also correlate with the force constant FM–O, though for cations of similar force constant the fraction of tetrahedral borate units (N4) strongly affects the thermal and mechanical properties. For paramagnetic Cu- and Mn-borate glasses, N4 was determined from the IR spectra after deducing the relative absorption coefficient of boron tetrahedral versus boron trigonal units, α = α4/α3, using NMR literature data of the diamagnetic glasses.
X-ray reflectivity imager with 15 W power X-ray source
Authors: Jiang Jinxing , Sakurai Kenji
Published: September 2016

X-ray reflectivity is usually used for the routine analysis of layered structures of uniform thin films. So far, the technique has some limitations in the application to more practical inhomogeneous/patterned samples. X-ray reflectivity imaging is recently developed technique and can give the reconstructed image from many X-ray reflection projections. The present article gives the instrumental details of the compact X-ray reflectivity imager. Though the power of X-ray source is only 15 W, it works well. The calibration of the system has been discussed, because it is particularly important for the present grazing incidence geometry. We also give a visualization example of the buried interface, physical meaning of the reconstructed image, and discussions about possibilities for improvement.
Structure and dynamics of polyelectrolyte surfactant mixtures under conditions of surfactant excess
Authors: Hoffmann Ingo , Simon Miriam , Farago Bela , Schweins Ralf , Falus Peter , Holderer Olaf , Gradzielski Michael
Published: September 2016

Oppositely charged polyelectrolyte (PE) surfactant mixtures can self-assemble into a large variety of mesoscopic structures, so-called polyelectrolyte surfactant complexes (PESCs). These structures directly affect the macroscopic behavior of such solutions. In this study, we investigated mixtures of the cationically charged PE JR 400 and the anionic surfactant SDS with the help of different neutron scattering and fluorescence methods. While an excess of PE charges in semi-dilute solutions causes an increase of viscosity, it has been observed that an excess of surfactant charges reduces the viscosity while precipitation is observed at charge equilibrium. The increase in viscosity had been investigated before and was attributed to the formation of cross links between PE chains. In this publication we focus our attention on the reduction of viscosity which is observed with an excess of surfactant charges. It is found that the PE chains form relatively large and densely packed clusters near the phase boundary on the surfactant rich side, thereby occupying less space and reducing the viscosity. For even higher surfactant concentrations, individual surfactant decorated PE chains are observed and their viscosity is found to be similar to that of the pure PE.
Droplet condensation on chemically homogeneous and heterogeneous surfaces
Authors: Ashrafi Amir , Moosavi Ali
Published: September 2016

Nucleation and growth of condensing droplets on horizontal surfaces are investigated via a 2-D double distribution function thermal lattice Boltzmann method. First, condensation on completely uniform surface is investigated and different mechanisms which cause dropwise and filmwise condensation are studied. The results reveal the presence of cooled vapor layer instability in the condensation on completely smooth surfaces. In the second step, condensation on chemically heterogeneous surfaces is investigated. Moreover, the effect of non-uniformity in the surface temperature is also studied. The results indicate that the vapor layer instability and the nucleation start from the heterogeneities. The effects of different numbers of heterogeneities, their distance, and hydrophobicity on the condensation are also inspected. It is shown that by increasing the hydrophobicity of the heterogeneities and considering an optimum space between the heterogeneities, maximum condensation performance can be achieved. Finally, condensation on wettability gradient surfaces is studied and the effects of the gradient form and contact angle of the core region on the condensation are studied. It is shown that hydrophobicity of the core region plays a key role in increasing the condensation performance. A heat transfer analysis and flow dynamics of dropwise condensation as a function of time is also presented and it is shown that the results are in good agreements with the previous theoretical and experimental results.
Thermal conductivity measurements of non-metals via combined time- and frequency-domain thermoreflectance without a metal film transducer
Authors: Wang L. , Cheaito R. , Braun J. L. , Giri A. , Hopkins P. E.
Published: September 2016

The thermoreflectance-based techniques time- and frequency-domain thermoreflectance (TDTR and FDTR, respectively) have emerged as robust platforms to measure the thermophysical properties of a wide array of systems on varying length scales. Routine in the implementation of these techniques is the application of a thin metal film on the surface of the sample of interest to serve as an opto-thermal transducer ensuring the measured modulated reflectivity is dominated by the change in thermoreflectance of the sample. Here, we outline a method to directly measure the thermal conductivities of bulk materials without using a metal transducer layer using a standard TDTR/FDTR experiment. A major key in this approach is the use of a thermal model with z-dependent heat source when the optical penetration depth is comparable to the beam sizes and measuring the FDTR response at a long delay time to minimize non-thermoreflectivity contributions to the modulated reflectance signals (such as free carrier excitations). Using this approach, we demonstrate the ability to measure the thermal conductivity on three semiconductors, intrinsic Si (100), GaAs (100), and InSb (100), the results of which are validated with FDTR measurements on the same wafers with aluminum transducers. We outline the major sources of uncertainty in this approach, including frequency dependent heating and precise knowledge of the pump and probe spot sizes. As a result, we discuss appropriate pump-frequency ranges in which to implement this TDTR/FDTR approach and present a procedure to measure the effective spot sizes by fitting the FDTR data of an 80 nm Al/SiO2 sample at a time delay in which the spot size sensitivity dominates an FDTR measurement over the substrate thermal properties. Our method provides a more convenient way to directly measure the thermal conductivities of semiconductors.
Long term reliability study and life time model of quantum cascade lasers
Authors: Xie Feng , Nguyen Hong-Ky , Leblanc Herve , Hughes Larry , Wang Jie , Wen Jianguo , Miller Dean J. , Lascola Kevin
Published: September 2016

Here, we present results of quantum cascade laser lifetime tests under various aging conditions including an accelerated life test. The total accumulated life time exceeds 1.5 × 106 device hours. The longest single device aging time was 46 500 hours without failure in the room temperature aging test. Four failures were found in a group of 19 devices subjected to the accelerated life test with a heat-sink temperature of 60 °C and a continuous-wave current of 1 A. Failure mode analyses revealed that thermally induced oxidation of InP in the semi-insulating layer is the cause of failure. An activation energy of 1.2 eV is derived from the dependence of the failure rate on laser core temperature. The mean time to failure of the quantum cascade lasers operating at a typical condition with the current density of 5 kA/cm2 and heat-sink temperature of 25 °C is expected to be 809 000 hours.
MHD spectra and coordinate transformations in toroidal systems
Authors: Predebon I. , Momo B. , Terranova D. , Innocente P.
Published: September 2016

A fully geometric approach is used to study the mutual spectral properties of different classes of MHD equilibria with symmetries defined by action-angle coordinates. We refer mostly to the helical equilibria of tokamak and reversed field pinch plasmas compared to the axisymmetric counterpart. Based on the existence of different coordinate systems, we show how the magnetic field and the vector potential are correspondingly evaluated, and how their spectral decompositions may largely vary. Most notably, a monochromatic perturbation in a reference frame can appear with a rich spectrum in another frame. The consequences on the interpretation of the measurements and the implications on the effectiveness of the externally applied magnetic fields on the plasma are discussed with practical examples.
Theoretical investigations on the N-polar GaN/AlxGa1-xN/GaN heterostructures: Considering the existence of both two-dimensional hole and electron gases
Authors: Yan Junda , Wang Quan , Wang Xiaoliang , Feng Chun , Xiao Hongling , Liu Shiming , Gong Jiamin , Liu Fengqi , Li Baiquan
Published: September 2016

In this paper, a theoretical study of N-polar GaN/AlxGa1-xN/GaN heterostructures is conducted systematically. The dependence of two-dimensional hole gas (2DHG, at the bottom AlxGa1-xN/GaN interface) and electron gas (2DEG, at the upper GaN/AlxGa1-xN interface) sheet densities on variables, such as GaN top layer thickness, AlxGa1-xN back barrier thickness, and Al content, is investigated. The effect of n-type doping in AlxGa1-xN and δ-doping concentrations in the GaN buffer on 2DHG and 2DEG sheet densities is also presented. For the unintentionally doped structure, the 2DHG-induced electric field E2DHG provides the only driving force in the 2DEG formation. Thus, in order to get high dense of 2DEG in such heterostructure, 2DEG and 2DHG shall coexist through proper AlxGa1-xN back barrier design. While for intentionally doped structure (with the n-type doped AlxGa1-xN back barrier layer or δ-doped GaN buffer layer), ionized donor-induced electric field Edonor is another driving force for 2DEG. The obtained insight offers indications for the structure design of the N-polar GaN/AlxGa1-xN/GaN high electron mobility transistors.
Tailoring oxygen vacancies at ZnO(11¯00) surface: An ab initio study
Authors: Korir K. K. , Catellani A. , Cicero G.
Published: September 2016

Oxygen vacancies in ZnO crystals have significant impacts on its properties and applications. On the basis of ab initio results, we describe the oxygen vacancy distribution and diffusion paths away from the ZnO(11¯00) surface, aiming to elucidate thermodynamics and kinetic stability of the vacancies and a possible control mechanism. In view of defect engineering and sensor applications, we propose efficient routes to chemically control the equilibrium concentration of the oxygen vacancies at ZnO surfaces by exposure to specific reactive gases: we show that the oxygen vacancy concentration can be increased using sulfur oxide as post-growth treatment, while under exposure to ozone, no significant amount of oxygen vacancies can be sustained on the surface.
Capillary flow of blood in a microchannel with differential wetting for blood plasma separation and on-chip glucose detection
Authors: Maria M. Sneha , Rakesh P. E. , Chandra T. S. , Sen A. K.
Published: September 2016

We report capillary flow of blood in a microchannel with differential wetting for the separation of a plasma from sample blood and subsequent on-chip detection of glucose present in a plasma. A rectangular polydimethylsiloxane microchannel with hydrophilic walls (on three sides) achieved by using oxygen plasma exposure enables capillary flow of blood introduced at the device inlet through the microchannel. A hydrophobic region (on all four sides) in the microchannel impedes the flow of sample blood, and the accumulated blood cells at the region form a filter to facilitate the separation of a plasma. The modified wetting property of the walls and hence the device performance could be retained for a few weeks by covering the channels with deionised water. The effects of the channel cross-section, exposure time, waiting time, and location and length of the hydrophobic region on the volume of the collected plasma are studied. Using a channel cross-section of 1000 × 400 μm, an exposure time of 2 min, a waiting time of 10 min, and a hydrophobic region of width 1.0 cm located at 10 mm from the device inlet, 450 nl of plasma was obtained within 15 min. The performance of the device was found to be unaffected (provides 450 nl of plasma in 15 min) even after 15 days. The purification efficiency and plasma recovery of the device were measured and found to be comparable with that obtained using the conventional centrifugation process. Detection of glucose at different concentrations in whole blood of normal and diabetic patients was performed (using 5 μl of sample blood within 15 min) to demonstrate the compatibility of the device with integrated detection modules.
Perspective: Accurate ro-vibrational calculations on small molecules
Authors: Tennyson Jonathan
Published: September 2016

In what has been described as the fourth age of quantum chemistry, variational nuclear motion programs are now routinely being used to obtain the vibration-rotation levels and corresponding wavefunctions of small molecules to the sort of high accuracy demanded by comparison with spectroscopy. In this perspective, I will discuss the current state-of-the-art which, for example, shows that these calculations are increasingly competitive with measurements or, indeed, replacing them and thus becoming the primary source of data on key processes. To achieve this accuracy ab initio requires consideration of small effects, routinely ignored in standard calculations, such as those due to quantum electrodynamics. Variational calculations are being used to generate huge lists of transitions which provide the input for models of radiative transport through hot atmospheres and to fill in or even replace measured transition intensities. Future prospects such as the study of molecular states near dissociation, which can provide a link with low-energy chemical reactions, are discussed.
A new approach to approximate equation-of-motion coupled cluster with triple excitations
Authors: Matthews Devin A. , Stanton John F.
Published: September 2016

Accurate methods for excited, ionized, and electron-attached states are critical to the study of many chemical species such as reactive intermediates, radicals, and ionized systems. The equation-of-motion coupled cluster singles, doubles, and triples (EOM-CCSDT) family of methods is very accurate (roughly similar in accuracy as for CCSDT calculations of the ground state), but the computational cost scales iteratively as the eighth power of the system size. Many approximations already exist, although most either correct only the excited state or require an iterative 𝒪(n7) procedure which can also be prohibitively expensive. In this paper, new methods, termed EOM-CCSD(T)(a) and EOM-CCSD(T)(a)*, are proposed which correct both the ground and excited states based on a shared effective Hamiltonian, and the latter of which includes only non-iterative corrections to both the CCSD and EOM-CCSD energies. These methods are found to significantly improve the description of excited and ionized potential energy surfaces, equilibrium geometries, and harmonic frequencies; the accuracy is very close to that of full EOM-CCSDT.
3-state Hamiltonians associated to solvable 33-vertex models
Authors: Crampé N. , Frappat L. , Ragoucy E. , Vanicat M.
Published: September 2016

Using the nested coordinate Bethe ansatz, we study 3-state Hamiltonians with 33 non-vanishing entries, or 33-vertex models, where only one global charge with degenerate eigenvalues exists and each site possesses three internal degrees of freedom. In the context of Markovian processes, they correspond to diffusing particles with two possible internal states which may be exchanged during the diffusion (transmutation). The first step of the nested coordinate Bethe ansatz is performed providing the eigenvalues in terms of rapidities. We give the constraints ensuring the consistency of the computations. These rapidities also satisfy Bethe equations involving 4 × 4 R-matrices, solutions of the Yang–Baxter equation which implies new constraints on the models. We solve them allowing us to list all the solvable 33-vertex models.
Highly (0001)-oriented Al-doped ZnO polycrystalline films on amorphous glass substrates
Authors: Nomoto Junichi , Inaba Katsuhiko , Osada Minoru , Kobayashi Shintaro , Makino Hisao , Yamamoto Tetsuya
Published: September 2016

Very thin aluminum-doped zinc oxide (AZO) films with a well-defined (0001) orientation and a surface roughness of 0.357 nm were deposited on amorphous glass substrates at a temperature of 200 °C by radio frequency magnetron sputtering, which are promising, particularly in terms of orientation evolution, surface roughness, and carrier transport, as buffer layers for the subsequent deposition of highly (0001)-oriented AZO polycrystalline films of 490 nm thickness by direct current (DC) magnetron sputtering. Sintered AZO targets with an Al2O3 content of 2.0 wt. % were used. DC magnetron sputtered AZO films on bare glass substrates showed a mixed (0001) and the others crystallographic orientation, and exhibited a high contribution of grain boundary scattering to carrier transport, resulting in reduced Hall mobility. Optimizing the thickness of the AZO buffer layers to 10 nm led to highly (0001)-oriented bulk AZO films with a marked reduction in the above contribution, resulting in AZO films with improved Hall mobility together with enhanced carrier concentration. The surface morphology and point defect density were also improved by applying the buffer layers, as shown by atomic force microscopy and Raman spectroscopy, respectively.
Investigation of laser induced breakdown in liquid nitromethane using nanosecond shadowgraphy
Authors: Guo Wencan , Zheng Xianxu , Yu Guoyang , Zhao Jun , Zeng Yangyang , Liu Cangli
Published: September 2016

A nanosecond time-resolved shadowgraphy is performed to observe a laser-induced breakdown in nitromethane. The digital delays are introduced between a pump beam and an illumination light to achieve a measuring range from 40 ns to 100 ms, which enable us to study the shock wave propagation, bubble dynamics, and other process of the laser-induced breakdown. Compared with distilled water, there are two obvious differences observed in nitromethane: (1) the production of a non-evaporative gas at the final stage, and (2) an absence of the secondary shock wave after the first collapse of the bubble. We also calculated the bubble energy in nitromethane and distilled water under a different incident energy. The results indicate that the bubble energy in nitromethane is more than twice as large as that in water. It is suggested that chemical reactions contribute to the releasing of energy.
Smith–Purcell terahertz radiation from laser modulated electron beam over a metallic grating
Authors: Kumar Pawan , Bhasin Lalita , Tripathi V. K. , Kumar Ashok , Kumar Manoj
Published: September 2016

We propose a novel scheme of terahertz (THz) radiation generation from the beat frequency modulation of an electron beam by two co-propagating lasers and the generation of terahertz radiation by the modulated beam passing over a periodic metallic grating. The lasers cause velocity modulation of the beam by exerting a longitudinal ponderomotive force on it. In the drift space between the modulator and metallic grating, the velocity modulation translates into density and current modulation. The modulated beam, propagating over the grating of specific wave number, induces space periodic image current in the conductor that emits beat frequency Smith–Purcell radiation. With 1 μm, 4 × 1016 W/cm2 lasers, beam current modulation of the order of 50% can be achieved at optimum lengths of the modulator and drift space. Employing 10 mA, 0.5 MeV short-period electron beam, propagating at a height of 50μm above the grating of period 150 μm, one may obtain THz radiated power of the order of 6 mW at 10 THz.
Optical response of cylindrical multilayers in the context of hydrodynamic convection-diffusion model
Authors: Dong Tianyu , Shi Yi , Lu Lizhen , Chen Feng , Ma Xikui , Mittra Raj
Published: September 2016

In this work, we generalize the cascading scattering matrix algorithm for calculating the optical response of concentric multilayered structures comprised of either plasmonic metal or dielectric, within the framework of hydrodynamic convection-diffusion model of electrodynamics. Two additional boundary conditions, namely, the continuity of first order pressure of free electron density and the continuity of normal components of free charge velocity, respectively, are adopted in order to handle the behaviour at interfaces involving metals. Scattering matrices at interfaces can be readily obtained and cascaded to obtain the modal coefficients in each layer by expanding electromagnetic waves in harmonic modes with cylindrical vector wave functions. We have validated the proposed method by analyzing the optical responses of several configurations of nanostructures, including a bi-metallic nanocylinder and a hyperlens. We found that nonlocal effects can be important for small structures, when the characteristic size is comparable to the Fermi wavelength. The proposed method shows its capability and flexibility to solve hybrid metal-dielectric multilayer structures even when the number of layers is large. Although we have discussed our method in the context of the retarded radiation regime, it can be applied in quasi-static scenarios without any difficulties. Furthermore, it may be extended to solve similar problems in other areas of physics, such as acoustics.
Quantum interference by localized scattering waves of gapless helical modes in narrow strips of topological insulators
Authors: Takagaki Y.
Published: September 2016

Quantum interference in scattering from a potential offset is investigated in narrow strips of two-dimensional systems described by the Bernevig-Hughes-Zhang Hamiltonian. Attention is focused on the situations where the transmission in the scattering region takes place around the Dirac point of topological insulators when the hybridization energy gap is eliminated by utilizing transverse interference. Apart from conventional periodic transmission modulation that takes place when the length of the potential offset region is varied, resonant disappearances of reflection occur for short potential offsets. The anomalous resonance appears not only for the four-band Hamiltonian but also for the two-band Hamiltonian, manifesting the generality of the phenomenon. Evanescent-like waves excited around the potential steps are indicated to be responsible for the anomalous behavior. The interference states can couple with each other and generic reduction in the amplitude of transmission modulation occurs upon coupling with the periodic modulation.
Controlling domain wall nucleation and propagation with temperature gradients
Authors: Mazo-Zuluaga J. , Velásquez E. A. , Altbir D. , Mejía-López J.
Published: September 2016

Field driven nucleation and propagation of transverse domain walls (DWs) in Fe nanowires under thermal gradients were studied using Monte Carlo simulations. Simulations identified that thermal gradients contribute to stabilizing nucleation of multiple DWs. The results also showed that the correct combination of a magnetic field and temperature gradients applied along a wire can provide a high degree of control over the direction, velocity, and acceleration of DW propagation, which is of paramount importance for technological applications.
Comparison of superconducting properties between FeSe0.5Te0.5/CeO2/SrTiO3 and FeSe0.5Te0.5/SrTiO3 thin films
Authors: Chen S. H. , Han Y. Y. , Liu J. Z. , Wang T. , Tian M. L. , Wen H. H. , Xing Z. W.
Published: September 2016

The electrical resistance behaviors under angle-dependent magnetic fields up to 16 T are investigated in superconducting FeSe0.5Te0.5 (FST) thin films grown on SrTiO3 (STO) substrates without or with a CeO2 buffer layer. It is found that the FST/CeO2/STO films have an enhanced superconducting transition temperature Tc and slightly increased superconducting anisotropy in comparison with the FST/STO films. The enhancement of Tc in the presence of the CeO2 buffer is closely related to the changes in both the out-of-plane lattice constant and Se-Fe-Se (Te-Fe-Te) bond angle.
Anti-reflective conducting indium oxide layer on nanostructured substrate as a function of aspect ratio
Authors: Park Hyun-Woo , Ji Seungmuk , Lim Hyuneui , Choi Dong-won , Park Jin-Seong , Chung Kwun-Bum
Published: September 2016

Antireflective conducting indium oxide layers were deposited using atomic layer deposition on a transparent nanostructured substrate grown using colloidal lithography. In order to explain the changes in the electrical resistivity and the optical transmittance of conducting indium oxide layers depending on various aspect ratios of the nanostructured substrates, we investigated the surface area and refractive index of the indium oxide layers in the film depth direction as a function of aspect ratio. The conformal indium oxide layer on a transparent nanostructured substrate with optimized geometry exhibited transmittance of 88% and resistivity of 7.32 × 10−4 Ω cm. The enhancement of electrical resistivity is strongly correlated with the surface area of the indium oxide layer depending on the aspect ratio of the nanostructured substrates. In addition, the improvement in transparency was explained by the gradual changes of the refractive index in the film depth direction according to the aspect ratio of the nanostructures.
Tunable microwave pulse generation using discharge plasmas
Authors: Biggs David R. , Cappelli Mark A.
Published: September 2016

The response of a microwave resonant cavity with a plasma discharge tube inside is (continuously or intermittently) filled with a plasma and studied both numerically and experimentally. The resonance frequency of the cavity-plasma system is sensitive to plasma densities from 1016 to 1020 m−3 corresponding to resonant frequencies of 12.3–18.3 GHz. The system is first characterized for its quasi-steady state response using a low frequency plasma discharge at 70 kHz and 125 V RMS. A plasma discharge is then driven with a high voltage pulse of 4 kV and a CW input microwave signal is converted to a pulsed output signal. The microwave pulse delay and pulse width are varied by selecting the input microwave frequency. The microwave input power is set to +20 dBm. The delay of the microwave pulse is also used as a diagnostic tool for measuring the variation of plasma density in time and, with numerical fitting, the discharge plasma recombination coefficient and diffusion timescales are estimated.
Spin accumulation at in-situ grown Fe/GaAs(100) Schottky barriers measured using the three- and four-terminal methods
Authors: Nam Song Hyeon , Park Tae-Eon , Park Youn Ho , Ihm Hae-In , Koo Hyun Cheol , Kim Hyung-jun , Han Suk Hee , Chang Joonyeon
Published: September 2016

We examined the spin accumulation in Fe/n-GaAs Schottky barriers to evaluate the accuracy of the three-terminal (3T) and four-terminal (4T) measurement geometries. A fully epitaxial Fe/n-GaAs junction was grown in situ using cluster molecular beam epitaxy without breaking the vacuum to exclude the formation of an oxide layer or surface roughness at the interface during intermixing. The spin resistance of the 4T nonlocal spin valve (ΔRNLSV = 0.71 Ω) was twice the value obtained using the 4T Hanle effect method (ΔR4TH = 0.35 Ω) at 10 K, as predicted theoretically, and this value remained constant over the temperature range examined, from 10 K to 77 K. The temperature-dependent spin lifetimes measured using the 3T and 4T Hanle effects exhibited similar behaviors. Although the spin resistance obtained using the 3T Hanle effect was enhanced compared with that obtained using the 4T effect, it was reasonable to conclude that the spin signals obtained from the 3T and 4T measurements originated from spin accumulation in n-GaAs due to the absence of an oxide tunnel barrier or a well-defined interface in our samples. These results completely ruled out any other sources of artifacts.
High-rectification near-field thermal diode using phase change periodic nanostructure
Authors: Ghanekar Alok , Ji Jun , Zheng Yi
Published: September 2016

We theoretically demonstrate workings of a near-field thermal rectification device that uses a phase change material to achieve asymmetry in radiative heat transfer. We exploit the temperature dependent dielectric properties of VO2 due to metal-insulator transition near 341 K. Analogous to an electrical diode, heat transfer coefficient is high in one direction while it is considerably small when the polarity of temperature gradient is reversed. We show that thermal rectification can be greatly enhanced by using 1-D rectangular and triangular VO2 surface gratings. With the introduction of periodic grating, rectification ratio is dramatically enhanced in the near-field due to reduced tunneling of surface waves across the interfaces for negative polarity. Our calculations predict that for minimal temperature difference of 20 K, the rectification ratio as high as 16 can be obtained, and it is maximum in existing literature for comparable operating temperatures and separation.
The investigation of physical conditions of boron uptake region in proton boron fusion therapy (PBFT)
Authors: Jung Joo-Young , Yoon Do-Kun , Lee Heui Chang , Lu Bo , Suh Tae Suk
Published: September 2016

We conducted a quantitative study to identify the effectiveness of proton boron fusion therapy (PBFT). Four simulation scenarios were designed to investigate the escalation in total dose with the proton boron reaction using a Monte Carlo n-particle extended (MCNPX 2.6.0) simulation. The peak integrated dose was obtained for three different physical conditions (i.e., boron uptake region (BUR) thickness, BUR location, and boron concentration) with differing proton beam energy (60–90 MeV). We found that the peak integrated dose was increased by up to 96.62% compared to the pristine proton Bragg-peak. For the synergetic effect to take place with 60–70 MeV proton beam, the BUR had to be at least 0.3 cm thick while spanning the Bragg-peak. Similarly to the thickness, the BUR location needed to be within 0.3 cm from the Bragg-peak when the thickness was maintained at 0.9 cm. An effective proton boron reaction required the boron concentration to be equal to or greater than 14.4 mg/g. These results demonstrate the impact of various physical and beam conditions of the PBFT, which are critical environmental factors for the treatment planning. We envision that this study will advance our understanding of the PBFT, which can be an invaluable treatment method for maximizing the potential of proton therapy.
Integrating biogeochemistry with multiomic sequence information in a model oxygen minimum zone
Authors: Louca Stilianos , Hawley Alyse K. , Katsev Sergei , Torres-Beltran Monica , Bhatia Maya P. , Kheirandish Sam , Michiels Céline C. , Capelle David , Lavik Gaute , Doebeli Michael , Crowe Sean A. , Hallam Steven J.
Published: September 2016

Significance

Modern molecular sequencing is beginning to provide great insight into microbial community structure and function at ecosystem scales. However, the quantitative integration of multiomic sequence information (DNA, mRNA, and protein) and geochemical processes has so far been elusive. Here, we develop a biogeochemical model that integrates geochemistry and multiomic sequence information to explain key metabolic processes in the oxygen-starved waters of Saanich Inlet, a model ecosystem for studying microbial community responses to oxygen minimum zone expansion. Our model largely explains DNA, mRNA, and protein distributions and sheds light on the metabolic networks coupling carbon, sulfur, and nitrogen transformations across a redox gradient. Our approach is extensible to other biogeochemical models incorporating feedbacks of global change on ecosystem functions.
Lateral association and elongation of vimentin intermediate filament proteins: A time-resolved light-scattering study
Authors: Lopez Carlos G. , Saldanha Oliva , Huber Klaus , Köster Sarah
Published: September 2016

Significance

The hierarchical assembly pathway of the cytoskeletal protein vimentin may be responsible for the astonishing mechanical properties of the emerging filaments, such as high flexibility and extensibility, and thus play a key role in cellular mechanics. A two-step assembly mechanism, involving a lateral and a subsequent elongational step, has been established; however, the elongational step could not be followed in solution. Here, we show direct in situ observation and modeling of the elongation reaction of the filaments on the relevant length and time scales, using time-resolved, multiangle static and dynamic light scattering. We thus achieve sufficient spatio-temporal resolution without the need of labeling, staining, or adsorption to substrates.
How curvature-generating proteins build scaffolds on membrane nanotubes
Authors: Simunovic Mijo , Evergren Emma , Golushko Ivan , Prévost Coline , Renard Henri-François , Johannes Ludger , McMahon Harvey T. , Lorman Vladimir , Voth Gregory A. , Bassereau Patricia
Published: September 2016

Significance

Lipid membranes are dynamic assemblies, changing shape on nano- to micron-sized scales. Some proteins can sculpt membranes by organizing into a molecular scaffold, dictating the membrane’s shape and properties. We combine microscopy, mathematical modeling, and simulations to explore how Bin/Amphiphysin/Rvs proteins assemble to form scaffolds on nanotubes. We show that the way protein locally deforms the membrane affects where it will nucleate before making a scaffold. In this process, the protein’s amphipathic helices—which shallowly insert into the membrane—seem dispensable. Surprisingly, the scaffold forms at low protein density on the nanotube. We simulate a structure of protein scaffolds at molecular resolution, shedding light on how these proteins may sculpt the membrane to facilitate important dynamic events in cells.
Mutational landscape, clonal evolution patterns, and role of RAS mutations in relapsed acute lymphoblastic leukemia
Authors: Oshima Koichi , Khiabanian Hossein , da Silva-Almeida Ana C. , Tzoneva Gannie , Abate Francesco , Ambesi-Impiombato Alberto , Sanchez-Martin Marta , Carpenter Zachary , Penson Alex , Perez-Garcia Arianne , Eckert Cornelia , Nicolas Concepción , Balbin Milagros , Sulis Maria Luisa , Kato Motohiro , Koh Katsuyoshi , Paganin Maddalena , Basso Giuseppe , Gastier-Foster Julie M. , Devidas Meenakshi , Loh Mignon L. , Kirschner-Schwabe Renate , Palomero Teresa , Rabadan Raul , Ferrando Adolfo A.
Published: September 2016

Significance

Relapsed acute lymphoblastic leukemia (ALL) is associated with chemotherapy resistance and poor prognosis. This study analyzes the emergence of acquired mutations in relapsed ALL samples, identifying genes implicated in disease progression and defining the process of clonal evolution leading to relapse. These analyses revealed that ALL relapse emerges from subclonal populations sharing only part of the mutations present in the dominant leukemia population found at diagnosis. Moreover, we show mutations in genes implicated in chemotherapy resistance pathways at relapse. RAS mutations are highly prevalent in high-risk ALL, yet their capacity to confer resistance to methotrexate and sensitivity to vincristine, two core drugs used in the treatment of ALL, influences their positive or negative selection at relapse.
Strain analysis of protein structures and low dimensionality of mechanical allosteric couplings
Authors: Mitchell Michael R. , Tlusty Tsvi , Leibler Stanislas
Published: September 2016

Significance

Regulation of biochemical activity is essential for proper cell growth and metabolism. Many proteins’ activities are regulated by interactions with other molecules binding some distance away from the proteins’ active sites. In such allosteric proteins, active sites should thus be mechanically coupled to spatially removed regulatory regions. We studied crystal and NMR structures of proteins in various regulatory and ligand-binding states. We calculated and analyzed distributions of strains throughout several proteins. Strains reveal allosteric and active sites and suggest that quasi-two-dimensional strained surfaces mediate mechanical couplings between them. Strain analysis of widely available structural data can illuminate protein function and guide future experimental investigation.
Short polyhistidine peptides penetrate effectively into Nicotiana tabacum-cultured cells and Saccharomyces cerevisiae cells
Authors: Kimura Sayaka , Kawano Tsuyoshi , Iwasaki Takashi
Published: September 2016

The polyhistidine peptides (PHPs) have been previously reported as novel cell-penetrating peptides and are efficiently internalized into mammal cells; however, penetration of PHPs into other cell types is unknown. In this study, the cellular uptake of PHPs in plant and yeast cells was found to be dependent on the number of histidines, and short PHPs (H6–H10 peptides) showed effective internalization. The H8 peptide showed the highest cell-penetrating capacity and localized to vacuoles in plant and yeast cells. Low-temperature conditions inhibited significantly the cellular uptake of short PHPs by both cells. However, net charge neutralization of PHPs also completely inhibited cellular uptake by plant cells, but not by yeast cells. These results indicate that short PHPs penetrate effectively into plant and yeast cells by similar mechanism with the exception of net charge dependency. The findings show the short PHPs are promising candidates for new delivery tools into plant and yeast cells.
Dynein-mediated trafficking negatively regulates LET-23 EGFR signaling
Authors: Skorobogata Olga , Meng Jassy , Gauthier Kimberley , Rocheleau Christian E.
Published: September 2016

Epidermal growth factor receptor (EGFR) signaling is essential for animal development, and increased signaling underlies many human cancers. Identifying the genes and cellular processes that regulate EGFR signaling in vivo will help to elucidate how this pathway can become inappropriately activated. Caenorhabditis elegans vulva development provides an in vivo model to genetically dissect EGFR signaling. Here we identified a mutation in dhc-1, the heavy chain of the cytoplasmic dynein minus end–directed microtubule motor, in a genetic screen for regulators of EGFR signaling. Despite the many cellular functions of dynein, DHC-1 is a strong negative regulator of EGFR signaling during vulva induction. DHC-1 is required in the signal-receiving cell and genetically functions upstream or in parallel to LET-23 EGFR. LET-23 EGFR accumulates in cytoplasmic foci in dhc-1 mutants, consistent with mammalian cell studies in which dynein is shown to regulate late endosome trafficking of EGFR with the Rab7 GTPase. However, we found different distributions of LET-23 EGFR foci in rab-7 versus dhc-1 mutants, suggesting that dynein functions at an earlier step of LET-23 EGFR trafficking to the lysosome than RAB-7. Our results demonstrate an in vivo role for dynein in limiting LET-23 EGFR signaling via endosomal trafficking.
A novel method to accurately locate and count large numbers of steps by photobleaching
Authors: Tsekouras Konstantinos , Custer Thomas C. , Jashnsaz Hossein , Walter Nils G. , Pressé Steve
Published: September 2016

Photobleaching event counting is a single-molecule fluorescence technique that is increasingly being used to determine the stoichiometry of protein and RNA complexes composed of many subunits in vivo as well as in vitro. By tagging protein or RNA subunits with fluorophores, activating them, and subsequently observing as the fluorophores photobleach, one obtains information on the number of subunits in a complex. The noise properties in a photobleaching time trace depend on the number of active fluorescent subunits. Thus, as fluorophores stochastically photobleach, noise properties of the time trace change stochastically, and these varying noise properties have created a challenge in identifying photobleaching steps in a time trace. Although photobleaching steps are often detected by eye, this method only works for high individual fluorophore emission signal-to-noise ratios and small numbers of fluorophores. With filtering methods or currently available algorithms, it is possible to reliably identify photobleaching steps for up to 20–30 fluorophores and signal-to-noise ratios down to ∼1. Here we present a new Bayesian method of counting steps in photobleaching time traces that takes into account stochastic noise variation in addition to complications such as overlapping photobleaching events that may arise from fluorophore interactions, as well as on-off blinking. Our method is capable of detecting ≥50 photobleaching steps even for signal-to-noise ratios as low as 0.1, can find up to ≥500 steps for more favorable noise profiles, and is computationally inexpensive.
Interlude
Authors: Gilliver Peter
Published: September 2016

This chapter assesses the contribution made to the ‘New English Dictionary’ by the volunteer sub-editors who worked on it during the 1860s and 1870s under the editorship of Frederick Furnivall. It examines the editorial policy as it was recommended by Furnivall and the ways in which this was interpreted by those sub-editors whose work has survived; it looks at the proposed inclusion policy, the quotations available to the sub-editors and how they were used, etymology, pronunciation, and the approach to the organization of dictionary entries, and considers how the lexicographical work carried out during this period differed from the later OED.
Manoeuvres: 1876–1879
Authors: Gilliver Peter
Published: September 2016

This chapter describes the search to find a publisher for the ‘New English Dictionary’, beginning with the abortive negotiations with Macmillan—in the course of which James Murray was identified as a suitable Editor of the Dictionary—and ending with the signing of contracts between Murray, the Philological Society, and Oxford University Press in 1879, following protracted negotiations between the parties over various aspects of editorial policy, the extent of the proposed dictionary, and the division of the anticipated profits. The roles of various key individuals in the negotiations, including Henry Sweet, Walter Skeat, Frederick Furnivall, Henry Liddell, Henry Hucks Gibbs, and Bartholomew Price, are described.