bluuebunny/crossref_metadata_2025 huggingface dataset:
Global oral health course: Perception among dental students in central India
Authors: Singh Abhinav , Purohit Bharathi
Published: September 2019

A questionnaire study was conducted among dental students in Central India. The study population included 264 dental students, who voluntarily completed a questionnaire, comprising of 16 close ended questions. There were 9 questions to judge knowledge and 5 questions for attitude assessment towards global oral health course. Two additional questions were included to assess the willingness to volunteer in international setting; and also, to assess dental student’s perspection on global oral health course. Chi Square test was used to compare between categorical variables. Analysis of Variance (ANOVA) was used to compare mean of knowledge and attitude scores. P value of ≤.05 was considered significant for all statistical analysis. Eighty seven percent of the surveyed students (222) stated that they would consider volunteering their dental skills as a future dentist in international setting. Majority of the students in the present study were not aware about the global oral health status (99.2%) and theoral health care systems of industrialized and emerging economies (99.2%), had not been trained to serve underserved population (68%), had not been trained in global health ethics (70.1%) and none of the students had been trained for cultural competence in addressing international oral health issues (100%). Most of the dental students were not aware, that, WHO created basic package of oral care (63%) about the primary health care strategy (59.5%) and about the role and functions of FDI (66.7%). The majority of students expressed a desire to volunteer their professional services in international settings. However few students knew about WHO’s BPOC or FDI’S role in global oral health. The findings indicate a need for global oral health course among dental students in Central India. (Eur J Dent 2012;6:295-301)
The effects of bluephase LED light
on fibroblasts
Authors: Malčić Ana Ivanišević , Pavičić Ivan , Trošić Ivančica , Simeon Paris , Katanec Davor , Krmek Silvana Jukić
Published: September 2019

Objectives: The aim of this study was to evaluate the effect of Bluephase light emitting diode (LED) light on cell viability, colony-forming ability and proliferation in V79 cell culture and to determine how much the temperature of the nutrient medium rose.

Methods: The investigation included a low (L), soft start (S) and high (H) illumination mode for 20,
40 and 80 seconds. The viability was determined by the trypan blue exclusion test, colony-forming
ability by counting colonies 7 days after exposure and cell proliferation by the cell counts on 5 postexposure
days. The temperature change during illumination was recorded (0.1˚C sensitivity).

Results:In each experimental condition, 90-95% of the cells were viable, which was in the same range as the controls. Colony-forming ability was not found to be significantly lower (P<.05). A significant decrease in proliferation was recorded on the 4th post-exposure day with S and H irrespective of time, on the 3rd day with S for 80 s and H for 40 and 80 s, and with S and H for 80 s on the 2nd day (P<.05).The temperature rise was significant with S (P<.05) and H (P<.05), irrespective of exposure duration.SL=78.43%, G=66.65% and P=67.95%. Comparing the %SMHC promoted by 5 soft drinks, SL = C > CL > P = G (P<.05). There was not significant correlation between %SMHC and the other variables tested for the five drinks (P><.05)

Conclusions:Dependent on total energy density, LED blue light affects the mitotic activity of cells
in its path to a certain extent. Altered mitotic activity was not noted with illumination at the low power
mode (intensity of 421.7 ±1.1 mW/cm2). The greatest temperature rise was 8.3 ˚C and occurred at the
highest intensity and exposure duration. (Eur J Dent 2012;6:311-317)
Spin-lattice relaxation processes of transition metal ions in a heavily cobalt doped ZnO: Phonon heating effect
Authors: Azamat D. V. , Badalyan A. G. , Baranov P. G. , Fanciulli M. , Lanc̆ok J. , Hrabovsky M. , Jastrabik L. , Dejneka A.
Published: September 2019

Inversion recovery with electron spin-echo detection has been used to study the electron spin-lattice relaxation rates 1/T1 for transition metal impurities in heavily cobalt-doped hydrothermally grown ZnO single crystals. The relaxation dynamics of Co2+ ions dominates the phonon bottleneck effect in the Orbach-Aminov process, which involves the modulation of the zero-field-splitting tensor. The relaxation mechanism may be treated in terms of phonon heating with fast rate of energy pump from Co2+ spins into the lattice phonon modes. The measurements reveal the cross-relaxation process in which the single Co2+ ions cross-relax to exchange-coupled clusters of cobalt ions. The higher temperature relaxation of Co2+ indicates an additional Orbach-Aminov process via a state of ∼226 cm−1 above the ground state Kramers doublet. It is shown that in this system Co2+ ions play a role of the rapidly relaxing centers, strongly mediating the spin-lattice relaxation of the other transition metal impurities, such as Mn2+ and Fe3+.
An enhanced extrapolation method based on particle swarm optimization-support vector regression to determine the friction coefficient between aircraft tire and runway surface
Authors: Zhan Liwei , Ma Fang , Song Xiaojun , Sun Hongwei , Li Chengwei
Published: September 2019

This paper proposes a hybrid pretreating method in the support vector regression (SVR) machines to enhance the extrapolated performance of the traditional method based on particle swarm optimization (PSO)-SVR. This method is introduced into a novel domain wherein the friction coefficient (COF) is extrapolated between the aircraft tire and the runway surface. It includes two parts: the normalized data and the extrapolated method for COF. The first part develops a novel data normalized method, which allows the experiment data to follow sine distribution (SN) instead of traditional linear distribution. For the second part, the SVR with the training set initially extrapolates a COF, and the COF is subsequently added into the original training set to build a new training sample. This process is repeated until the extrapolation is finished. This method is named step-wise (SW) extrapolation. PSO is used to optimize the regularization constant C, the parameter gamma γ, and epsilon parameter ε in SVR. Finally, this study indicates that the proposed method (SN-SW-PSO-SVR) is more suitable for the extrapolation of the COF between the airplane tire and the runway surface than other extrapolated methods.
Modeling interacting city traffic with finite acceleration and braking capacities
Authors: Medina Rafael O. , Rogan José , Ramirez Max , Toledo Benjamín A. , Valdivia Juan A.
Published: September 2019

Understanding the fundamental interactions in the complex behavior of one car moving in a sequence of traffic lights necessarily implies the inclusion of finite braking and accelerating capabilities. This characteristic is usually not considered in the standard cellular automaton models, where car interactions are the main concern. Therefore, here we develop a model which includes interactions and finite braking and accelerating capabilities, filling the gap between a standard cellular automaton model that considers car interactions but infinite braking and accelerating capabilities and the continuous one car model that includes finite braking and accelerating capabilities but does not consider, as the name indicates, car interactions. The proposed new model bridge these two seemingly different approaches in an effort to investigate how the traffic jams are produced. We found that, in the appropriate limits, we can reproduce the complex behavior of the one car continuous model and the dynamics close to the resonance induced by the interacting cars, forced by the traffic lights. In the processes of introducing car interactions, we observe how the average velocity decreases to finally obtain traffic jams, which are an emergent state in which the traffic lights control the generation of pulses of cars but do not control its average speed. This model is expected to improve our understanding of the complexity that appears in city traffic situations, as the finite braking and accelerating capabilities are necessary to describe the vehicle dynamics, the control strategy of traffic light synchronization, the motion of buses in segregated lights, and the whole urban design.
A simple levitated-drop tensiometer
Authors: Arcenegui-Troya J. , Belman-Martínez A. , Castrejón-Pita A. A. , Castrejón-Pita J. R.
Published: September 2019

A reliable, simple, and affordable liquid tensiometer is presented in this paper. The instrument consists of 72 ultrasonic transmitters in a tractor beam configuration that levitates small liquid samples (droplets) in air. Under operation, the instrument imparts a pressure instability that causes the droplet to vibrate while still levitating. Droplet oscillations are then detected by a photodiode, and the signal is recorded by an oscilloscope. The frequency of these oscillations is obtained and then used to obtain the effective surface tension of the sample. The instrument operates at the millisecond scale time (t < 12.5 ms), with very small liquid volumes (∼0.5 μl), and the sample is recoverable after testing. The instrument has been experimentally validated with acetone, ethanol, Fluorinert FC-40, water, and whole milk.
XUV diagnostic to monitor H-like emission from B, C, N, and O for the W7-X stellarator
Authors: Fornal Tomasz , Książek Ireneusz , Kaczmarczyk Jacek , Figacz Waldemar , Kubkowska Monika , Burhenn Rainer , Kunkel Falk , Laube Ralph , Renard Sebastien ,   W7-X Team
Published: September 2019

The “C/O Monitor” system for the Wendelstein 7-X (W7-X) stellarator is a dedicated spectrometer with high throughput and high time resolution (order of 1 ms) for fast monitoring of content of low-Z impurities in the plasma. The observed spectral lines are fixed to Lyman-α lines of H-like atoms of carbon (3.4 nm), oxygen (1.9 nm), nitrogen (2.5 nm), and boron (4.9 nm). The quality of the wall condition will be monitored by the measurements of oxygen being released from the walls during the experiments. The strong presence of carbon is an indication for enhanced plasma-wall interaction or overload of plasma facing components. The presence of nitrogen (together with oxygen) may indicate a possible leakage in the vacuum system, whereas the intensity of the spectral emission of boron indicates the status of the boron layer evaporated onto the wall in order to reduce the influx of heavier steel ingredients or oxygen. The spectrometer will be fixed in a nearly horizontal position and is divided into two vacuum chambers, each containing two spectral channels assigned to two impurity species. Each channel will consist of a separate dispersive element and detector. The line-of-sight of both subspectrometers will cross at the main magnetic axis. This paper presents the conceptual design of the “C/O Monitor” for W7-X which has already entered the executive stage.
Electrically detected electron nuclear double resonance in 4H-SiC bipolar junction transistors
Authors: Waskiewicz Ryan J. , Manning Brian R. , McCrory Duane J. , Lenahan Patrick M.
Published: September 2019

We demonstrate high signal-to-noise electrically detected electron-nuclear double resonance measurements on fully processed bipolar junction transistors at room temperature. This work indicates that the unparalleled analytical power of electron-nuclear double resonance in the identification of paramagnetic point defects can be exploited in the study of defects within fully functional solid-state electronic devices.
Chaos in networks of coupled oscillators with multimodal natural frequency distributions
Authors: Smith Lachlan D. , Gottwald Georg A.
Published: September 2019

We explore chaos in the Kuramoto model with multimodal distributions of the natural frequencies of oscillators and provide a comprehensive description under what conditions chaos occurs. For a natural frequency distribution with M peaks it is typical that there is a range of coupling strengths such that oscillators belonging to each peak form a synchronized cluster, but the clusters do not globally synchronize. We use collective coordinates to describe the intercluster and intracluster dynamics, which reduces the Kuramoto model to 2M−1 degrees of freedom. We show that under some assumptions, there is a time-scale splitting between the slow intracluster dynamics and fast intercluster dynamics, which reduces the collective coordinate model to an M−1 degree of freedom rescaled Kuramoto model. Therefore, four or more clusters are required to yield the three degrees of freedom necessary for chaos. However, the time-scale splitting breaks down if a cluster intermittently desynchronizes. We show that this intermittent desynchronization provides a mechanism for chaos for trimodal natural frequency distributions. In addition, we use collective coordinates to show analytically that chaos cannot occur for bimodal frequency distributions, even if they are asymmetric and if intermittent desynchronization occurs.
Effect of surface roughness on heat transfer and entropy generation of mixed convection in nanofluid
Authors: Ting Kevin , Mozumder Aloke K. , Das Prodip K.
Published: September 2019

In this study, mixed convective heat transfer and entropy generation of Al2O3-water in a lid-driven square cavity with roughness elements on the bottom surface have been studied. The vertical sidewalls of the cavity are adiabatic, and horizontal walls are maintained at a constant temperature, while the top wall is moving at a constant velocity. Various Reynolds numbers, Rayleigh numbers, and nanoparticles concentrations have been considered. The wavy bottom wall of the cavity is determined by the number and amplitude of the roughness elements. It has been observed that the larger amplitude reduces the heat transfer rate while increasing the total entropy generation and the average Bejan number (Beavg). Conversely, the roughness elements reduce the heat transfer rate and total entropy generation while increasing Beavg. It has been further observed that the amplitude has a greater effect on the entropy generation and Beavg than the number of roughness elements. In addition, increasing the Reynolds and Rayleigh numbers increases the average Nusselt number and total entropy generation, while reducing Beavg. Addition of nanoparticles in a base fluid increases the heat transfer while minimizing the total entropy generation. Beavg rises with nanoparticle concentrations. The lowest entropy generation for nanofluid could be achieved at the low Rayleigh number and Reynolds number with a fixed number and amplitude of the roughness elements. In the cases studied, total entropy generation is greatly affected by heat transfer irreversibility while fluid friction irreversibility plays a minor role in the total entropy generation enhancement.
A new simultaneous measurement system of wide Q-range small angle neutron scattering combined with polarized Fourier transform infrared spectroscopy
Authors: Kaneko Fumitoshi , Kawaguchi Tatsuya , Radulescu Aurel , Iwase Hiroki , Morikawa Toshiaki , Takata Shin-ichi , Nishiura Masayoshi , Hou Zhaomin
Published: September 2019

Small angle neutron scattering (SANS) is a versatile and convenient method to investigate the higher order structure of molecular assembly systems. However, the more complicated a system of interest, the more difficult the interpretation in the SANS profile. In order to increase the reliability of structural analysis on a complicated system, it is desirable to obtain different kinds of structural information from the same sample simultaneously. Polarized infrared spectroscopy is able to provide information about the molecular structure, concentration, and orientation of each chemical species in a system. In order to utilize these advantages of polarized infrared spectroscopy, a simultaneous measurement system was built by incorporating a Fourier transform infrared (FTIR) spectrometer into a time-of-flight small angle neutron scattering instrument covering a wide Q range. Using this system, simultaneous measurements of wide- and small-angle neutron scattering and polarized FTIR spectroscopy was realized for the first time.
Characterization of the 2-methylvinoxy radical + O2 reaction: A focal point analysis and composite multireference study
Authors: Davis Matthew M. , Weidman Jared D. , Abbott Adam S. , Douberly Gary E. , Turney Justin M. , Schaefer Henry F.
Published: September 2019

Vinoxy radicals are involved in numerous atmospheric and combustion mechanisms. High-level theoretical methods have recently shed new light on the reaction of the unsubstituted vinoxy radical with O2. The reactions of 1-methylvinoxy radical and 2-methylvinoxy radical with molecular oxygen have experimental high pressure limiting rate constants, k∞, 5–7 times higher than that of the vinoxy plus O2 reaction. In this work, high-level ab initio quantum chemical computations are applied to the 2-methylvinoxy radical plus O2 system, namely, the formation and isomerization of the 1-oxo-2-propylperoxy radical, the immediate product of O2 addition to the 2-methylvinoxy radical. Multireference methods were applied to the entrance channel. No barrier to O2 addition could be located, and more sophisticated treatment of dynamic electron correlation shows that the principal difference between O2 addition to the vinoxy and 2-methylvinoxy radicals is a larger steric factor for 2-methylvinoxy + O2. This is attributed to the favorable interaction between the incoming O2 molecule and the methyl group of the 2-methylvinoxy radical. Via the focal point approach, energetics for this reaction were determined, in most cases, to chemical accuracy. The coupled-cluster singles, doubles, and perturbative triples [CCSD(T)] correlation energy and Hartree–Fock energies were independently extrapolated to the complete basis set limit. A correction for the effect of higher excitations was computed at the CCSDT(Q)/6-31G level. Corrections for the frozen-core approximation, the Born–Oppenheimer approximation, the nonrelativistic approximation, and the zero-point vibrational energy were included. From the 1-oxo-2-propylperoxy radical, dissociation to reactants is competitive with the lowest energy isomerization pathway. The lowest energy isomerization pathway ultimately forms acetaldehyde, CO, and ·OH as the final products.
Oscillation quenching and phase-flip bifurcation in coupled thermoacoustic systems
Authors: Dange Suraj , Manoj Krishna , Banerjee Subham , Pawar Samadhan A. , Mondal Sirshendu , Sujith R. I.
Published: September 2019

Oscillatory instabilities, although ubiquitous in nature, are undesirable in many situations such as biological systems, swaying of bridges and skyscrapers, aero-acoustic flutter, prey-predator and disease spread models, and thermoacoustic systems, where they exhibit large amplitude periodic oscillations. In the present study, we aim to study the suppression mechanism of such undesired oscillations in a pair of thermoacoustic oscillators, also known as horizontal Rijke tubes. These oscillators are coupled through a connecting tube whose length and diameter are varied as coupling parameters. With the variation of these parameters, we show the first experimental evidence of rich dynamical phenomena such as synchronization, amplitude death, and phase-flip bifurcation in coupled identical thermoacoustic oscillators. We discover that when frequency and amplitude mismatch are introduced between these oscillators, quenching of oscillations in one or both the oscillators occurs with further ease, through the mechanisms of amplitude death and partial amplitude death. Finally, we show that the effectiveness of coupling is sensitive to the dimensions of the connecting tube which can be directly correlated with the time delay and coupling strength of the system.
Experiments on self-sustained oscillations of leeward vortices over a hemisphere cylinder
Authors: Jiang Hong-Gang , Ma Bao-Feng
Published: September 2019

Recent numerical studies have indicated the existence of a new type of vortex unsteadiness around a hemisphere cylinder from low to high angles of attack, characterized by large-scale alternate oscillations of leeward-vortex pairs. This investigation conclusively confirms the existence of vortex oscillations in experiment by directly measuring oscillatory vortex structures and explores their origin and evolution with increasing Reynolds number (Re = 957–6780, Re = U∞D/ν, where U∞ is freestream velocity, D is the diameter of the body, and ν is the coefficient of kinematic viscosity). The results indicate that the Reynolds number strongly influences the stability of the vortex pairs and oscillations of the vortices. As Re is less than a critical Re (Rec), only weak horizontal oscillations (antisymmetric modes) were observed downstream of the vortex pairs at low frequencies and a small amplitude. At Re > Rec, stronger vortex oscillations were observed with a mean dimensionless frequency of St = 0.11 (St = f D/U∞), where the amplitude of the oscillations increased with the value of Re. In this case, the oscillations of the vortex pairs consisted of antisymmetric and symmetric modes, where the antisymmetric modes were dominant and corresponded to alternate oscillations of the vortex pairs, and the symmetric modes were much weaker and corresponded to in-phase oscillations of the vortex pairs. The estimated wavelengths imply that the vortex oscillations originated in long-wave instabilities. However, the behaviors of these instabilities were significantly different from those of Crow-type long-wave instabilities in which symmetric modes that are insensitive to the Reynolds number are dominant.
Measurement of avalanche multiplication utilizing Franz-Keldysh effect in GaN p-n junction diodes with double-side-depleted shallow bevel termination
Authors: Maeda Takuya , Narita Tetsuo , Ueda Hiroyuki , Kanechika Masakazu , Uesugi Tsutomu , Kachi Tetsu , Kimoto Tsunenobu , Horita Masahiro , Suda Jun
Published: September 2019

Avalanche multiplication characteristics of GaN p-n junction diodes (PNDs) with double-side-depleted shallow bevel termination, which exhibit nearly ideal avalanche breakdown, were investigated by photomultiplication measurements using sub-bandgap light. In GaN PNDs under reverse bias conditions, optical absorption induced by the Franz-Keldysh (FK) effect is observed, resulting in a predictable photocurrent. The avalanche multiplication factors were extracted as a ratio of the measured values to the calculated FK-induced photocurrent. In addition, the temperature dependences of the avalanche multiplications were also investigated.
Adsorption and desorption of DNA-functionalized beads in glass microfluidic channels
Authors: Raimondo Theresa M. , McCalla Stephanie E.
Published: September 2019

Integrated microfluidic devices for the purification, amplification, and detection of nucleic acids are a prevalent area of research due to their potential for miniaturization, assay integration, and increased efficiency over benchtop assays. These devices frequently contain micrometer-sized magnetic beads with a large surface area for the capture and manipulation of biological molecules such as DNA and RNA. Although magnetic beads are a standard tool for many biological assays, beads functionalized with biological molecules can adhere to microchannel walls and prevent further manipulation of the beads within the channel. Here, we analyze the effects of solution composition, microchannel hydrophobicity, and bead surface hydrophobicity on DNA-functionalized bead adhesion in a borosilicate glass microfluidic device. Bead adhesion is primarily a result of adsorption of the bead-linked DNA molecule to the microchannel wall; >81% of beads are consistently removed when not functionalized with DNA. Hydrophobicities of both the microchannel walls and the microbead surface are the primary determinants of bead adhesion, rather than electrostatic interactions and ion bridging. Surprisingly, DNA-functionalized bead adhesion in a standard RNA amplification solution was virtually eliminated by using hydrophobic microbeads with hydrophobic microchannel walls; under such conditions, 96.6 ± 1.6% of the beads were removed in one 43 nl/s, 10-min wash. The efficiency of a downstream RNA amplification reaction using DNA-functionalized beads did not appear to be affected by the hydrophobicity of the microbead surface. These findings can be applied to assays that require the efficient use of magnetic beads in DNA-based microfluidic assays.
Effects of alloying elements and temperature on thermal conductivity of ferrite
Authors: Wang Guanghua , Li Yanxiang
Published: September 2019

The thermal conductivity of steel and cast iron is often much lower than that of pure ferrite. One of the main reasons is the addition of alloying elements, which reduces the thermal conductivity of ferrite. Based on the theory of metal heat conduction, relationships between the thermal conductivity of ferrite and contents of alloying elements as well as temperature are established. Then, the effects of alloying elements and temperature on the thermal conductivity of ferrite are quantitatively and qualitatively analyzed, respectively. At 300 K, the effects of Si and Al on the thermal conductivity of ferrite are significant, while the effects of Mn, Cr, and Mo are relatively small and that of W is the weakest. However, the superposition of another element may change the influence of an alloying element on the thermal conductivity of ferrite. Within 300–800 K, the temperature dependence of electrical resistivity for alloyed ferrite is much weaker than that of pure ferrite. Although the phonon thermal conductivity of ferrite decreases monotonously with temperature, the electron thermal conductivity of ferrite changes from monotonic decreasing to monotonic increasing with the addition of alloying elements. The overall impact will make the thermal conductivity of alloyed ferrite with temperature decrease monotonously at low alloying content, and the latter increase first then decrease at medium alloying content, and finally increase monotonously at high alloying content.
Analyte capture in an array of functionalized droplets for a regenerable biosensor
Authors: Azzopardi C.-L. , Chollet F. , Manceau J.-F. , Boireau W.
Published: September 2019

We describe in this work an advanced microfluidic chip for the capture of bioanalyte on the surface of droplets arranged in a dense array. We show the procedure for generating, functionalizing, and arranging the droplets inside the device for capturing a specific bioanalyte. Then, we demonstrate the capacity of the array to capture analyte from a cross-flowing liquid, using a biotin/streptavidin model. The paper also proposes to use the droplets array, after integration with acoustic detection, as a regenerable detection interface for bioanalyte sensing. We model the arrangement of droplet in dense array and show that they present a larger effective capture surface and shorter capture distance than standard flat surface biosensor of the same footprint. As the droplets can be easily evacuated and replaced inside the device analysis chamber, the proposed biosensor would allow biointerface regeneration and chain measurement without dismounting the device.
Exact stationary solutions of the parametrically driven and damped nonlinear Dirac equation
Authors: Quintero Niurka R. , Sánchez-Rey Bernardo
Published: September 2019

Two exact stationary soliton solutions are found in the parametrically driven and damped nonlinear Dirac equation. The parametric force considered is a complex ac force. The solutions appear when their frequencies are locked to half the frequency of the parametric force, and their phases satisfy certain conditions depending on the force amplitude and on the damping coefficient. Explicit expressions for the charge, the energy, and the momentum of these solutions are provided. Their stability is studied via a variational method using an ansatz with only two collective coordinates. Numerical simulations confirm that one of the solutions is stable, while the other is an unstable saddle point. Consequently, the stabilization of damped Dirac solitons can be achieved via time-periodic parametric excitations.
Large flexoelectric response in PMN-PT ceramics through composition design
Authors: Li Chunchun , Wang Zhiguo , Li Fei , Rao Zhenggang , Huang Wenbin , Shen Zhenjiang , Ke Shanming , Shu Longlong
Published: September 2019

Flexoelectricity yields electric polarization through graded strains and exists in various kinds of solid dielectrics but usually with a weak coupling response. In this letter, several Bi-doped Pb(Mg2/3Nb1/3)O3-xPbTiO3 (PMN-xPT) ferroelectric ceramics were prepared and the interplay of their piezoelectricity and flexoelectricity was systematically investigated. The largest flexoelectric response (∼300 μC/m) was 30 times larger than that of pure PMN-PT and was observed in the Bi-doped PMN-32PT, where the after poling piezoelectric coefficients were also the largest (990 pC/N) among all the compositions. This suggests that the apparent flexoelectricity in ferroelectrics is highly related to the bulk piezoelectricity. Therefore, introducing a local structural heterogeneity is considered as a feasible approach to achieve an ultrahigh piezoelectric response while also providing an ultrahigh flexoelectricity.
Investigation of resistive switching in copper/InGaZnO/Al2O3-based memristor
Authors: Gan Kai-Jhih , Chang Wei-Chiao , Liu Po-Tsun , Sze Simon M.
Published: September 2019

This work investigates the resistive switching mechanism in the Cu/TiW/InGaZnO/Al2O3/Pt-based memristor. By introducing the Al2O3 layer, the nanoscale diameter of the Cu filament decreased from 6.51 to 0.83 nm as the current compliance decreases from 1 mA to 50 μA. The resistive switching memory characteristics, such as a large ratio of high-resistance state (HRS)/low-resistance state (LRS) (∼107), stable switching cycle stability (>9 × 102), and multilevel operation, are observed and apparently improved compared to the counterpart of the Cu/TiW/InGaZnO/Pt memory device. These results are attributed to the control of Cu formation/dissolution by introducing the Al2O3 nanolayer at the InGaZnO/Pt interface. The findings of this study can not only improve the performance of the amorphous InGaZnO memristor but also be promising for potential applications of next-generation flat-panel displays in wearable devices.
The grain-size effect on thermal conductivity of uranium dioxide
Authors: Shrestha K. , Yao T. , Lian J. , Antonio D. , Sessim M. , Tonks M. R. , Gofryk K.
Published: September 2019

We have investigated the grain-boundary scattering effect on the thermal transport behavior of uranium dioxide (UO2). The polycrystalline samples having different grain-sizes (0.125, 1.8, and 7.2μm) have been prepared by a spark plasma sintering technique and characterized by x-ray powder diffraction, scanning electron microscope, and Raman spectroscopy. The thermal transport properties (the thermal conductivity and thermoelectric power) have been measured in the temperature range of 2–300 K, and the results were analyzed in terms of various physical parameters contributing to thermal conductivity in these materials in relation to grain-size. We show that thermal conductivity decreases systematically with lowering grain-size in the temperatures below 30 K, where the boundary scattering dominates the thermal transport. At higher temperatures, more scattering processes are involved in the heat transport in these materials, making the analysis difficult. We determined the grain-boundary Kapitza resistance that would result in the observed increase in thermal conductivity with grain-size and compared the value with Kapitza resistances calculated for UO2 using molecular dynamics from the literature.
Evaluating intrinsic mobility from transient terahertz conductivity spectra of microcrystal samples of organic molecular semiconductors
Authors: Yada H. , Sekine H. , Miyamoto T. , Terashige T. , Uchida R. , Otaki T. , Maruike F. , Kida N. , Uemura T. , Watanabe S. , Okamoto T. , Takeya J. , Okamoto H.
Published: September 2019

In microcrystal samples of the prototypical organic molecular semiconductors rubrene and C10-DNTT (2,9-didecyl-dinaphtho[2,3-b:2′,3′-f]thieno[3,2-b]thiophene), we measured spectra of complex optical conductivity caused by photocarriers with optical-pump terahertz-probe spectroscopy. We analyzed the σ̃ω spectra using the Drude-Smith model and evaluated the DC mobility μDC, which includes extrinsic effects, and the intrinsic mobility μint. The resulting μDC and μint values are comparable to the mobility values obtained using transport measurements of polycrystalline and single-crystalline field-effect transistors, respectively. This correspondence demonstrates that the intrinsic mobility values of organic molecular semiconductors can be evaluated from the measurements of microcrystal samples using transient terahertz spectroscopy.
Frequency doubling in elastic mechanisms using buckling of microflexures
Authors: Farhadi Machekposhti Davood , Herder Just L. , Tolou Nima
Published: September 2019

Microtransmission mechanisms made of elastic materials present an opportunity for exploring scalable mechanical systems integrated with sophisticated functionalities. This paper shows how the fundamentally limited range of motion in elastic mechanisms can be circumvented to create a frequency doubling functionality analog to angular velocity doubling in classical gears. The proposed mechanism utilizes the elastic deformation of its internal architecture and buckling of microflexures to perform frequency doubling kinematics. We demonstrate this by the fabrication of a microtransmission device for application in mechanical wrist watches. A key benefit of the proposed method is that such a transmission system can be integrated and fabricated as an embedded part of microarchitected materials to boost the frequency characteristics of energy storage, actuators, and inertial sensors to perform adequately for different applications.
Multiphonon resonant Raman scattering and the second-order Raman processes in the excitonic luminescence of ZnO
Authors: Hu B. C. , Zhou N. , Zhang Q. Y. , Ma C. Y.
Published: September 2019

Multiphonon assisted optical emission processes of ZnO in the vicinity of excitonic luminescence were investigated using the excitation-emission maps and the photoluminescence (PL) excitation spectra recorded at different emission photon energies. Multiphonon resonant Raman scattering (RRS) was found to have the temperature dependence similar to the excitonic luminescence, but not to be influenced by the surface conditions and annealing process. The multiphonon RRS and the longitudinal optical (LO) phonon replicas of PL lines were substantiated to originate from the cascade scattering of exciton polaritons with successively emitting LO phonons. The second-order Raman processes were observed to take part in the capture of exciton polaritons by the defects, forming the neutral donor bound excitons.
Asymmetric delay attack on an entanglement-based bidirectional clock synchronization protocol
Authors: Lee Jianwei , Shen Lijiong , Cerè Alessandro , Troupe James , Lamas-Linares Antia , Kurtsiefer Christian
Published: September 2019

We demonstrate an attack on a clock synchronization protocol that attempts to detect tampering of the synchronization channel using polarization-entangled photon pairs. The protocol relies on a symmetrical channel, where propagation delays do not depend on the propagation direction, for correctly deducing the offset between clocks—a condition that could be manipulated using optical circulators, which rely on static magnetic fields to break the reciprocity of propagating electromagnetic fields. Despite the polarization transformation induced within a set of circulators, our attack creates an error in time synchronization while evading detection.
Perturbation potentials to overcome order/disorder transitions in alchemical binding free energy calculations
Authors: Pal Rajat K. , Gallicchio Emilio
Published: September 2019

We investigate the role of order/disorder transitions in alchemical simulations of protein-ligand absolute binding free energies. We show, in the context of a potential of mean force description, that for a benchmarking system (the complex of the L99A mutant of T4 lysozyme with 3-iodotoluene) and for a more challenging system relevant for medicinal applications (the complex of the farnesoid X receptor with inhibitor 26 from a recent D3R challenge) that order/disorder transitions can significantly hamper Hamiltonian replica exchange sampling efficiency and slow down the rate of equilibration of binding free energy estimates. We further show that our analytical model of alchemical binding combined with the formalism developed by Straub et al. for the treatment of order/disorder transitions of molecular systems can be successfully employed to analyze the transitions and help design alchemical schedules and soft-core functions that avoid or reduce the adverse effects of rare binding/unbinding transitions. The results of this work pave the way for the application of these techniques to the alchemical estimation with explicit solvation of hydration free energies and absolute binding free energies of systems undergoing order/disorder transitions.
Facile purification of CsPbX3 (X = Cl−, Br−, I−) perovskite nanocrystals
Authors: Wang Chujie , Chesman Anthony S. R. , Yin Wenping , Frazer Laszlo , Funston Alison M. , Jasieniak Jacek J.
Published: September 2019

CsPbI3 perovskite nanocrystals are a promising optoelectronic material when stabilized in their cubic phase. While ongoing efforts have addressed this structural challenge through a variety of meta-stabilization approaches, the postsynthesis purification of these nanocrystal dispersions has remained a challenge. In this article, we undertake a detailed investigation into the chemical, optical, and structural changes that arise during purification of CsPbI3 nanocrystals. It is found that nanocrystal degradation can only be avoided through the judicious control of additives within each purification cycle. Under optimized additive-to-nanocrystal ratios, multiple purification cycles can be readily achieved, while retaining the quality and phase stability of the CsPbI3. This facile purification protocol ensures the preparation of high purity and high quality CsPbI3 nanocrystal inks that are suitable for better characterization or integration in optoelectronic devices. The approach has been generalized for CsPbX3 (X = Cl−, Br−, and I−).
Annealing effect on laser-induced magnetization dynamics in Co/Ni-based synthetic antiferromagnets with perpendicular magnetic anisotropy
Authors: Wu Guanjie , Chen Shaohai , Lou Shitao , Liu Yaowen , Jin Q. Y. , Zhang Zongzhi
Published: September 2019

We report a comprehensive study of annealing treatment modulation on the laser-induced ultrafast magnetic behaviors in antiferromagnetically exchange-coupled [Ni/Co]4/Ru/[Co/Ni]3 multilayers with perpendicular magnetic anisotropy (PMA). Magnetic hysteresis loops indicate that the uniaxial PMA field Hkeff decreases monotonously with the increase in annealing temperature Ta, but the variation of interlayer coupling field Hex is rather complicated. Time-resolved magnetic-optical Kerr effect (MOKE) measurements demonstrate that the laser-excited demagnetization and precession process relies significantly on Ta. Upon laser impulsion, the MOKE signal immediately shows a nonchanging transient increase and decrease with H increasing for low Ta, but only the ultrafast decreasing behavior for high Ta. From the subsequent dynamic precession spectra, the optical and acoustic precession modes are identified. By fitting the field-dependent frequency curves via the deduced dispersion relations, both Hkeff and Hex are determined and their variation trends agree well with the results from the static magnetic measurement. Moreover, it is found that the critical field where the ultrafast signal decrease occurs is dependent on the co-effect of Hkeff and Hex, whereas the maximum field at which the optical mode precession disappears shares the same trend as Hex. The magnetic damping of acoustic mode is seen to increase with Ta due to the increased inhomogeneities. Our findings provide a deep understanding of the magnetic properties in synthetic antiferromagnetic multilayers with high annealing temperatures, which will be helpful for designing advanced spintronic devices.
Nanoparticles are a promising solution to thermal energy challenges in electronic devices
Authors: Mandel Savannah
Published: September 2019

Scientists discover the addition of nanoparticles in nanofluid increases heat transfer and reduces total entropy generation.
Educational pamphlets for improving uptake of cancer screening: a systematic review
Authors: Teo Boon See , Li Esther , Tan Clara , Munro Yasmin Lynda
Published: September 2019

ABSTRACT INTRODUCTIONThe effectiveness of cancer screening programmes is highly dependent on screening uptake. Many interventions have been tested to increase screening uptake. AIMThe goal of this study was to evaluate the effectiveness of cancer screening pamphlets as a standalone intervention. The outcome of interest was uptake of cancer screening tests. METHODSA systematic review was performed on the effectiveness of pamphlets compared to usual care without pamphlets. We searched five databases for research papers in English from 2000 up to May 2019. Randomised controlled trials were included. This research group independently selected studies, extracted data, assessed risk of bias and then compared the information as a group. RESULTSA total of nine trials involving 4912 participants met our inclusion criteria, of which five were about colorectal cancer screening, three were about prostate cancer screening and one was about lung cancer screening. Five of the nine trials showed that pamphlets alone increased uptake significantly, while the remaining four trials did not show significant effects. DISCUSSIONThere is some evidence that pamphlets increase uptake for cancer screenings, especially for colorectal cancer. Due to the small number of studies in this area, generalisability could be limited.
Repeat prescribing safety survey
Authors: Lillis Steven , Macklin Nicki , Thorn Michael , Wicks Emma , Good Kristin , Lack Liza , Medlicott Richard , Proffitt Catherine , Rodenburg Helen , Souter Vanessa , Duncan Pam , Bercinskas Lucia , Fletcher Stephanie , Molloy Alison
Published: September 2019

ABSTRACT

INTRODUCTIONRepeat prescribing is an accepted part of general practice activities in New Zealand and in many developed countries. However, there has been little research on how this service is used in New Zealand, or on clinicians’ attitudes towards it.

AIMTo discover the opinions of vocationally registered general practitioners (GPs) and general practice registrars regarding repeat prescribing, availability of practice policy and mechanisms for issuing such prescriptions.

METHODSA survey was developed by an expert group and shared through the Royal New Zealand College of General Practitioners’ (the College) weekly newsletter, epulse, inviting members to participate in the survey. The survey was also emailed to registrars.

RESULTSIn total, 144 vocationally registered GPs and 115 registrars responded (n=259), giving a response rate of 3.2% for GPs and 12.7% for registrars. Patient convenience and time efficiency for the practice were the most commonly cited reasons for repeat prescribing. Registrars had low awareness of practice policy on repeat prescribing and only one-quarter of practices had an orientation pack that contained advice on repeat prescribing.

DISCUSSIONBetter practice systems are likely to improve the safety profile of repeat prescribing and should be addressed. There is substantial unwanted variability currently in these practice systems.
Two new species of Poecilanthe (Leguminosae: Papilionoideae: Brongniartieae) from Bolivia and Brazil
Authors: Lewis G. P. , Tebbs M. , Wood J. R. I.
Published: September 2019

Two new legume species, Poecilanthe goiasana G.P.Lewis from Brazil and Poecilanthe boliviana G.P.Lewis from Bolivia, are described and illustrated. Previously seven species of the genus were recorded from Brazil, and one from Bolivia. A summary is given of the current circumscription of the papilionoid legume tribe Brongniartieae Hutch., to which Poecilanthe belongs.
Borealin–nucleosome interaction secures chromosome association of the chromosomal passenger complex
Authors: Abad Maria A. , Ruppert Jan G. , Buzuk Lana , Wear Martin , Zou Juan , Webb Kim M. , Kelly David A. , Voigt Philipp , Rappsilber Juri , Earnshaw William C. , Jeyaprakash A. Arockia
Published: September 2019

Chromosome association of the chromosomal passenger complex (CPC; consisting of Borealin, Survivin, INCENP, and the Aurora B kinase) is essential to achieve error-free chromosome segregation during cell division. Hence, understanding the mechanisms driving the chromosome association of the CPC is of paramount importance. Here using a multifaceted approach, we show that the CPC binds nucleosomes through a multivalent interaction predominantly involving Borealin. Strikingly, Survivin, previously suggested to target the CPC to centromeres, failed to bind nucleosomes on its own and requires Borealin and INCENP for its binding. Disrupting Borealin–nucleosome interactions excluded the CPC from chromosomes and caused chromosome congression defects. We also show that Borealin-mediated chromosome association of the CPC is critical for Haspin- and Bub1-mediated centromere enrichment of the CPC and works upstream of the latter. Our work thus establishes Borealin as a master regulator determining the chromosome association and function of the CPC.
Serotonin transport in the 21st century
Authors: Rudnick Gary , Sandtner Walter
Published: September 2019

Serotonin (5-hydroxytryptamine [5-HT]) is accumulated within nerve endings by the serotonin transporter (SERT), which terminates its extracellular action and provides cytoplasmic 5-HT for refilling of synaptic vesicles. SERT is the target for many antidepressant medications as well as psychostimulants such as cocaine and ecstasy (3,4-methylenedioxymethamphetamine). SERT belongs to the SLC6 family of ion-coupled transporters and is structurally related to several other transporter families. SERT was studied in the 1970s and 1980s using membrane vesicles isolated from blood platelets. These studies led to a proposed stoichiometry of transport that has been challenged by high-resolution structures of SERT and its homologues and by studies of SERT electrophysiology. Here, we review the original evidence alongside more recent structural and electrophysiological evidence. A self-consistent picture emerges with surprising insights into the ion fluxes that accompany 5-HT transport.
Data framework for electricity price setting in competitive environment
Authors: Oprea Simona-Vasilica , Bâra Adela , Preoțescu Dan
Published: September 2019

The generic term of electricity market is in fact a very complex sector of activity, being the result of the interaction of several markets, such as: the bilateral contracts market, the day-ahead market, the balancing market, intra-day market, and the market for ancillary services. In these circumstances, an electricity supplier needs to address the setting of the selling electricity price to the end consumers. The basic objectives to be pursued are as follows: return on sale for a period of at least one year, maintaining competition on the market, use of a user-friendly price system, financial insurance against fluctuations in the market, and ensuring a cash-flow corresponding to the good functioning of the firm. Considering these objectives, in this paper, we propose a data framework to handle electricity consumption data and a procedure to set the electricity price in competitive environment of the electricity markets. In this regard, a case study for an office building that also includes a restaurant is depicted.