bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of trace H2 O and O2 on SF6 decomposition products under arcing conditions in electric power equipment
Authors: Yang Ren , Xu Mengyuan , Guan Chen , Yan Jing , Geng Yingsan
Published: October 2018

SF6 has been widely used as an insulating and arc extinguishing medium in electric power equipments. Detection of gas decomposition products is an important means for condition monitoring and fault diagnosis. Trace H2 O and O2 have a significant influence on the species and concentrations of SF6 decomposition products. It is important to explore the influence mechanism of trace H2 O and O2 on SF6 decomposition products under arcing conditions. A series of SF6 decomposition tests were carried out on a 40.5kV SF6 circuit breaker, and a gas chromatograph and an electrochemical sensor were used to measure decomposed components. First, the H2 O content remained constant, and the O2 content and arcing energy changed in the tests. It has been found that the decomposition products of SF6 are SOF2, SO2, CO, CO2, CF4, C2 F6 and C3 F8. Then, the O2 content remained constant, and the H2 O content changed. The decomposition products are mainly SOF2, SO2, CO and CO2. Concentrations of all these decomposition products increase first and then tend to be stable slowly over time, but change differently with the increase of H2 O and O2 contents, because H2 O and O2 play different roles in the formation process of each decomposition characteristic components.
Fire resistance test of transformers filled with natural ester insulating liquid
Authors: Cai Shengwei , Chen Cheng , Guo Huihao , Chen Shaobing , Zhou Zandong , Guo Zhaofeng
Published: October 2018

Natural ester fluids, as a renewable, biodegradable liquid dielectric, its flash point is above 300°C, and the burning point exceeds 330°C, high flash point liquids known as ‘less flammable’ liquids. There is a possibility applying the natural ester fluid immersed transformer instead of dry type transformer in high fire resistance requirement occasion. In order to verify the fire resistance of natural ester insulating oil transformer, set forth a series of contrast test between natural ester insulating oil and mineral insulating oil, including flash point, burning point, explosion limits, metal hot surface test, and burning plate test. Through developing burning test platform of transformer to launch the burning test for 10 kV transformer of natural ester insulating oil. The results show that the transformer filled with natural ester fluid cannot burn for 30 min in the case of severe external fire, which provides a relatively abundant time for fire extinguishing and has certain fireproof performance. In addition, by improving the mechanical strength of transformer tank, install the specific pressure relief devices and using high temperature seal, bushing etc., which can improve the fire resistance of transformers filled with natural ester insulating fluids.
Application of adaptive sampling algorithm in solving the scattering field of UHVAC/DC transmission lines
Authors: Shi Jia , Tang Bo , Hao Bin , Yang Jiawei
Published: October 2018

Using MBPE technology can quickly predict the approximation of the frequency response of transmission lines' scattering field. However, equal interval sampling method is usually used in the calculation of transmission lines' scattering field, it results a possibility that the sampled data may be with lack of important points, which makes the fitting results difficult to control, or samples duplicated information to increase the amount of calculation. In order to calculate more accurately, the adaptive sampling algorithm is introduced here. In the fast solution of frequency response of transmission lines' scattering field, it greatly improved the accuracy of results. Finally, compared with those of the traditional interval sampling methods, the results of using adaptive sampling algorithm were in line with the actual situation.
Influence of transition resistance and fault moment on DC system commutation process caused by two‐phase fault of AC system
Authors: Song Jinzhao , Li Yongli , Zhang Yunke , Zhang Jingqiu
Published: October 2018

Commutation failure caused by the fault of AC system at inverter side seriously affects the safety and stability of high‐voltage direct current (HVDC) system. Although two‐phase fault is a typical asymmetrical fault, the studies on commutation failure caused by two‐phase fault are few compared with the studies on commutation failure caused by three‐phase fault or single‐phase fault. In this study, the features of two‐phase fault occurring on commutation bus is analysed theoretically. The analysis shows that the transition resistance will affect the amplitude and phase of the commutation voltage at Y‐Y and Y‐D1 transformer valve sides. Furthermore, the change regularity of the commutation voltage along with the change of transition resistance is given. Taking interphase short circuit as an example, the influence of different fault moments on commutation process is studied. For the first commutation process before the fault, the possible cases of commutation failure are given for fault moments in one cycle. For the first commutation process after the fault, a calculation method of critical voltage drop is given. Simulation results verify the correctness of the analysis.
Fuzzy quasi‐PRD control for the photovoltaic inverter with LCL filter
Authors: Cao Like , Yu Yongjin , Han Qingchun
Published: October 2018

With the development of photovoltaic power generation technology, a large number of micro‐power grid with distributed generation system have appeared in remote areas. It has the longer transmission line between the traditional power grid and the inverter of the distributed generation system. This caused the equivalent network impedance would be increased and would weak the power‐grid characteristics. When the photovoltaic inverter is connected to a weaker power grid, the bandwidth of the control system of the inverter will be reduced. Using the traditional PR control to solve the problem is not ideal. This paper proposes fuzzy quasi‐PRD control to improve the current quality. The inverter with the LCL filter has the peak of the resonance oscillation, it will affect the stability of the system. The paper adopts the adjustable virtual damping to suppress resonance. At last, the idea is verified by MATLAB/Simulink. The results show that the fuzzy quasi‐PRD control method has better control performance, and dynamic tracking characteristics.
Reliability evaluation of MMC system considering working conditions
Authors: Zheng Tao , Huang Meng , Zhu Lingyi , Zha Xiaoming
Published: October 2018

The reliability is a key issue of the high‐voltage high‐power modular multilevel converter (MMC) system due to the usage of fragile insulated gate bipolar transistor (IGBT) modules. In this study, it is proposed that the reliability of the MMC system can be modelled and calculated considering practical working conditions. Firstly, based on the MMC power level, the power loss and the junction temperature are analysed. Then considering the aging process of IGBT, the failure rate is calculated with temperature coefficient. Finally, the MMC system failure rate and its relationships with some key parameters are found.
Application of tower grounding device equivalent model in the calculation of transmission line back‐flashover
Authors: Chen Huaifei , Cai Hansheng , Ni Yang , Jia Lei , Lu Hailiang , Liu Gang , Lan Lei
Published: October 2018

The modelling of tower grounding device is the key for calculation of lightning strike response and lightning withstand level. In order to solve this problem, this study proposes a method to calculate the lightning response of transmission line grounding device by combining the advantages of CDEGS and EMTP software. Firstly, the authors calculate the frequency domain response of the tower grounding model in CDEGS; then the result is fitted according to modified vector fitting method to obtain the rational approximation expression of the impedance function. Furtherly, the corresponding equivalent circuits of tower grounding device is established in EMTP to realise accurate simulation of grounding device lightning strike response. The results show that the equivalent circuit model is more accurate than non‐linear resistance model. Then, the factors that influence the lightning response and lightning withstand level are analysed based on the above method according to an actual transmission line model, which can provide reference for the lightning protection and grounding design.
Parameters tuning and coordination control of the frequency limit controller
Authors: You Guangzeng , Guo Xiangyang , Zhu Xinchun , Li Lingfang , Xiao Liang , Xu Zheng , Lu Shaoqi
Published: October 2018

The frequency stability in the sending‐end network with renewable energy generating units should be paid attention especially for an asynchronous interconnection system. When the DC blocking fault occurs in the system, the problem of high frequency in the sending‐end network can be suppressed by using the frequency limit controller (FLC). This study introduces the structure and the parameters tuning method of the FLC, and the parameters optimisation method is proposed to avoid FLC acting repeatedly. In the study, a case is studied, and the results show that the FLC is important in the sending‐end network. Finally, aiming at the coordination problem between multiple FLCs, a control strategy based on FLC influence coefficient is proposed in the study, and the strategy can suppress the over regulation effectively.
O2 signature in thin and thick O2−H2O ices
Authors: Müller B. , Giuliano B. M. , Bizzocchi L. , Vasyunin A. I. , Caselli P.
Published: October 2018

Aims. In this paper we investigate the detectability of the molecular oxygen in icy dust grain mantles towards astronomical objects.

Methods. We present a systematic set of experiments with O2−H2O ice mixtures designed to disentangle how the molecular ratio affects the O2 signature in the mid- and near-infrared spectral regions. All the experiments were conducted in a closed-cycle helium cryostat coupled to a Fourier transform infrared spectrometer. The ice mixtures comprise varying thicknesses from 8 × 10−3 to 3 μm. The absorption spectra of the O2−H2O mixtures are also compared to the one of pure water. In addition, the possibility to detect the O2 in icy bodies and in the interstellar medium is discussed.

Results. We are able to see the O2 feature at 1551 cm−1 even for the most diluted mixture of H2O:O2 = 9:1, comparable to a ratio of O2/H2O = 10% which has already been detected in situ in the coma of the comet 67P/Churyumov-Gerasimenko. We provide an estimate for the detection of O2 with the future mission of the James Webb Space Telescope (JWST).
Sonographic Venous Velocity Index Identifies Patients with Chronic Kidney Disease and Severe Diastolic Dysfunction
Authors: Meier Markus , Jabs Wolfram Johannes , Guthmann Maria , Geppert Gesa , Aydin Ali , Nitschke Martin
Published: October 2018

Diagnosing cardiorenal syndrome (CRS) in patients with chronic kidney disease (CKD) continues to remain challenging in outpatient practice. In this study, we investigate whether a newly developed venous velocity ultrasound index (VVI) can differentiate between patients with CRS and patients with CKD of other cause or normal renal function (NRF).

Patients with CRS (n=30), CKD (n=30), and NRF (n=30) were included in the study. For each patient, duplex ultrasound scans of intrarenal segmental veins were retrospectively analyzed. The VVI was calculated from the renal venous doppler curve as the ratio of the maximal positive venous velocity to the maximal negative venous velocity. Patients with CRS were compared to age-matched controls with NRF and to GFR-matched controls with CKD.

The GFRs of patients with CRS and those with CKD were comparable (26.4±5 and 25.6±7 ml/min/m2), as was the age in patients with CRS and NRF (6 ±12 years and 68±16 years, respectively). There was no significant difference in ejection fraction between patients with CRS and those with CKD (44.2±6.2% vs. 47.4 ±7.2), but there was a significant decrease compared to those with NRF (52.6 ±5.1, p<0.01). The VVI was significantly higher in the CRS group (0.81± 0.18) compared to the CKD group (0.18± 0.17, p<0.01) or NRF group (0.22± 0.20, p<0.01). The positive predictability of CRS was 96.4% in patients with VVI values of >0.6.

The newly developed VVI was useful in successfully predicting severe diastolic dysfunction (CRS) in patients with severe kidney injury in outpatient care.
Nachruf auf Prof. Hans-Dieter Rösler, Rostock
Authors: Meyer-Probst Bernhard , Kropp Peter
Published: October 2018

Am 9.7.2018 verstarb Prof. Dr. Hans-Dieter Rösler aus Rostock, 91-jährig. Der Verstorbene war Ehrenmitglied der Deutschen Gesellschaft für Medizinische Psychologie und ist für die Entwicklung der Klinischen Psychologie in Ostdeutschland nicht wegzudenken.
Synthesis of Fmoc- and Boc-Protected (2S,5S)- and (2R,5R)-5-Aminomethylprolines
Authors: Heinrich Markus , Bartuschat Amelie , Hegmann Nina
Published: October 2018

The proline derivatives (2S,5S)dmamPro, (2S,5S)N-Boc-amPro and (2R,5R)dmamPro are useful building blocks for peptides since they allow conformational fixation of peptidyl–CO–N-prolyl bonds in the unusual cis conformation. The stereoselective syntheses of these dimethylaminomethyl-prolines is achieved from literature-known precursors with overall yields of 23% [over 8 steps for (2S,5S)dmamPro], 33% [over 9 steps for (2S,5S)N-Boc-amPro] and 12% [over 8 steps for (2R,5R)dmamPro]. The applicability of (2S,5S)N-Boc-amPro in peptide synthesis is demonstrated through the preparation of an Fmoc-Val-amPro-OMe dipeptide.
Enantioselective Electrochemical Lactonization Using Chiral Iodoarenes as Mediators
Authors: Gao Wen-Chao , Xiong Zi-Yue , Pirhaghani Shafigh , Wirth Thomas
Published: October 2018

The enantioselective electrochemical lactonization of diketo acid derivatives using chiral iodoarenes as redox mediators is reported for the first time. Good to high stereoselectivities are observed in the lactonization and also in intermolecular α-alkoxylations of diketo ester derivatives. This enantioselective process was then adapted to an electrochemical flow microreactor where only small amounts of supporting electrolyte were necessary.
Supratentorial and Infratentorial Approaches to Pineal Surgery: A Database Analysis
Authors: Rosenberg David M. , Geever Brett W. , Patel Akash S. , Chaker Anisse N. , Bhimani Abhiraj D. , Kheirkhah Pouyan , Hobbs Jonathan G. , Esfahani Darian R. , Mehta Ankit I.
Published: October 2018

Objectives Neoplasms involving the pineal gland are rare. When they do occur, tumor resection is anatomically challenging and is traditionally addressed by either a supratentorial or an infratentorial approach. To date, no large, multicenter studies have been performed that systematically analyze outcomes comparing these two approaches. This study aimed to evaluate outcomes for patients undergoing pineal neoplasm resection, comparing supratentorial and infratentorial approaches.

Design Retrospective database review.

Setting Multi-institutional database.

Participants From 2005 to 2016, 60 patients were identified, with 13 undergoing a supratentorial approach and 47 undergoing an infratentorial approach.

Main Outcome Measures Patient demographics, comorbidities, and 30-day postoperative outcomes were investigated using the American College of Surgeons National Surgical Quality Improvement Program database. Demographics, readmission, reoperation, and complication rates were analyzed and compared with previous studies.

Results Patient demographics were similar between these two groups. The overall complication rates for the supratentorial and infratentorial approaches were 30.8 and 17%, respectively, and the difference was not statistically significant. The most common medical complications encountered were respiratory and hematological.

Conclusion As the first multi-institutional database analysis of approaches to the pineal gland, this study provides an analysis of patient demographics, comorbidities, and postoperative complications. After controlling for preoperative risk factors and demographic characteristics, no statistically significant differences in postoperative outcomes were found between infratentorial and supratentorial approaches. The mean readmission, reoperation, and complication rates were found to be 2.1, 8.3, and 20%, respectively. The lack of significant difference between approaches suggests that clinical decision-making should depend upon anatomical considerations and physician preference, although the complications illustrated here may provide some preoperative guidance.
Structured Training for Fetal Diagnostic Skills in a Maternal-Fetal Medicine Fellowship
Authors: Antony Kathleen , Khurshid Nauman , Trampe Barbara , Gupta Vivek , Iruretagoyena J. , Stewart Katharina , Shah Dinesh
Published: October 2018

Objective The American Institute of Ultrasound in Medicine has described what constitutes a detailed fetal anatomic examination but what comprises an appropriate physician training program has not been described. The purpose of this paper is to describe a highly-structured program developed by our center to train maternal-fetal medicine fellows in a systematic approach to fetal diagnostic imaging.

Study Design We describe this approach in three phases. Phase I: Development of Skills as a Perinatal Sonographer, Phase II: Mentored Evolution to a Perinatal Sonologist and Phase III: Supervised Independent Practice as Consultant-in-training.

Results This curriculum was implemented in 2006. Of the eight maternal-fetal medicine fellows who completed this program, 100% were capable of following this curriculum and 100% felt comfortable performing and interpreting detailed sonograms including sonograms with significant and uncommon anomalies. Qualitative feedback was also positive. Finally, this structured approach resulted in an increase in the average total number of sonograms interpreted.

Conclusion Our curriculum, by following the explicit guidelines and expectations set out by the American Institute of Ultrasound in Medicine and the American Board of Obstetrics and Gynecology for practicing maternal-fetal medicine fellowship graduates, provides an opportunity to explore national standardization for this component of training.
Dynamics of water drop detachment from a superhydrophobic surface induced by an ultrasonic field
Authors: Geng D. L. , Hu L. , Hong Z. Y. , Xie W. J. , Wei B.
Published: October 2018

We present the dynamics of sessile water drops during their detachment from a superhydrophobic surface induced by ultrasound. The superhydrophobic surface not only serves as a reflector of the ultrasound emitted from the source but also reduces the adhesive force between the drop and the solid surface. The drop is subject to an acoustic radiation force in the ultrasonic field due to the nonlinear effect of the latter. By shifting the reflector upward to approach the first resonance distance, the sessile drop is first elongated in the vertical direction, with its contact line and contact angle decreasing, and finally detaches from the superhydrophobic surface when the acoustic radiation force overcomes the sum of the gravitational and adhesive forces. The acoustic radiation pressure and acoustic radiation force are calculated by solving the acoustic field with the finite element method. The results indicate that the distribution of acoustic radiation pressure provides the upward force to make the drop detach. After its detachment from the reflector, the drop undergoes vertical vibration accompanied by shape oscillations. Oscillations of a water drop that is pinned on the reflector are also demonstrated.
Effects of cholesterol on the binding of the precursor neurotransmitter tryptophan to zwitterionic membranes
Authors: Lu Huixia , Martí Jordi
Published: October 2018

The characterization of the microscopical forces between the essential α-amino-acid tryptophan, precursor of the neurotransmitter serotonin and of the hormone melatonin, and the basic components of cell membranes and their environments (phospholipids, cholesterol, ionic species, and water) is of central importance to elucidate their local structure and dynamics as well as the mechanisms responsible for the access of tryptophan to the interior of the cell. We have performed nanosecond molecular dynamics simulations of tryptophan embedded in model zwitterionic bilayer membranes made by di-palmitoyl-phosphatidyl-choline and cholesterol inside aqueous sodium-chloride solution in order to systematically examine tryptophan-lipid, tryptophan-cholesterol, and tryptophan-water interactions under liquid-crystalline phase conditions. Microscopic properties such as the area per lipid, lipid thickness, radial distribution functions, hydrogen-bonding lengths, atomic spectral densities, and self-diffusion coefficients have been evaluated. Our results show that the presence of tryptophan significantly affects the structure and dynamics of the membrane. Tryptophan spends long periods of time at the water-membrane interface, and it plays a central role by bridging a few lipids and cholesterol chains by means of hydrogen-bonds. The computed spectral densities, in excellent agreement with experimental infrared and Raman data, revealed the participation of each atomic site of tryptophan to the complete spectrum of the molecule. Tryptophan self-diffusion coefficients have been found to be in between 10−7 and 10−6 cm2/s and strongly depending of the concentration of cholesterol in the system.
Numerical simulation of plasma power deposition on hollow cathode walls using particle-in-cell and Monte Carlo collision method
Authors: Cao Shuai , Ren Junxue , Tang Haibin , Zhang Zhe , Wang Yibai , Cao Jinbin , Chen Zhiyuan
Published: October 2018

The plasma parameters and power deposition on the walls in an orificed hollow cathode (HC) were investigated by employing the particle-in-cell (PIC) numerical method combined with Monte Carlo collisions. A new plasma power-deposition model based on the particle-wall interactions is presented. The distributions of plasma potential, plasma density, and power deposition from particles bombarding the wall surface were calculated in the PIC simulation, for the HC operating in the diode regime with a discharge current of 10.0 A and a gas flow rate of 3.5 sccm. The simulation results suggested that the electrons exhibited non-Maxwellian electron energy distributions in the insert region and that quasi-neutrality was violated outside the bulk plasma system. In addition, the results showed that the plasma power deposited on the emitter, on the upstream surface of the orifice plate, on the orifice inner wall, and on the downstream surface of the orifice plate was in the ratio of about 4:3:1:2. The results also indicated that charge exchange collisions can dramatically weaken power deposition from plasma ions.
A high-speed data acquisition system based on FPGA for tokamak
Authors: Shu Shuangbao , Wang Le , Liu Dongmei , Chen Meiwen , Zhang Yuzhong , Luo Jiarong , Ji Feng
Published: October 2018

The Experimental Advanced Superconducting Tokamak (EAST) device aims to achieve a steady-state and long-pulse discharge over 1000 s. An embedded high-speed data acquisition system based on a field-programmable gate array (FPGA) for EAST is designed in this study. A cyclone FPGA is used as the master chip, and a TI’s analog-to-digital conversion (ADC) chip is used to complete ADC. One acquisition system board consists of four ADC chips. The acquired data are compressed and stored into a disk array through a Peripheral Component Interconnect (PCI) Express interface and then uploaded to the data server. One board can collect the signals of eight channels synchronously. A number of such boards can be used to collect additional channel signals. Experimental results show that the system can reach 80 MSps and the sampling precision can reach 12 bits with 1250 s continuous sampling. The system integrates signal conditioning, data acquisition, and data processing into a single board and provides an architecture with high integration and portability levels.
Characterization and calibration of the Thomson scattering diagnostic suite for the C-2W field-reversed configuration experiment
Authors: Ottaviano A. , Schindler T. M. , Zhai K. , Parke E. , Granstedt E. , Thompson M. C. ,   TAE Team
Published: October 2018

The new C-2W Thomson scattering (TS) diagnostic consists of two individual subsystems for monitoring electron temperature (Te) and density (ne): one system in the central region is currently operational, and the second system is being commissioned to monitor the open field line region. Validating the performance of the TS’s custom designed system components and unique calibration of the detection system and diagnostic as a whole is crucial to obtaining high precision Te and ne profiles of C-2W’s plasma. The major components include a diode-pumped Nd:YAG laser which produces 35 pulses at up to 20 kHz, uniquely designed collection lenses with a fast numerical aperture, and uniquely designed polychromators with filters sets to optimize a Te ranging from 10 eV to 2 keV. This paper describes the design principles and techniques used to characterize the main components of the TS diagnostic on C-2W, as well as the results of Rayleigh scattering calibrations performed for the whole system response.
Atomistic insights toward strengthening of GeTe phase change material by impurity doping and grain boundary engineering
Authors: Liu Ruirui , Zhou Xiao , Zhai Jiwei , Song Jun
Published: October 2018

The interplay between impurities (i.e., C and N) and the twin boundary (TB) in GeTe was systematically investigated by first principles calculations. The strong segregation propensity of C and N at TBs was demonstrated. Moreover, TBs were shown to restrain impurity diffusion, exerting a trapping effect on impurities. With the presence of impurities, the mechanical strength of TB was significantly enhanced. Such a strengthening effect arises from the strong covalent bonding between the impurity (C and N) and host atoms at TB. The present work provides atomic-scale understanding underlying impurity-induced TB strengthening and offers new insights based on the synergy between grain boundary engineering and impurity doping into designing more robust and stable phase-change material devices.
Absolute cross section for DNA damage induced by low-energy (10 eV) electrons: Experimental refinements and sample characterization by AFM
Authors: Brodeur N. , Cloutier P. , Bass A. D. , Bertrand G. , Hunting D. J. , Grandbois M. , Sanche L.
Published: October 2018

This work describes multiple experimental improvements for measuring absolute cross sections of DNA damage induced by low-energy electrons in nanometer-thick films in vacuum. Measurements of such cross sections are particularly sensitive to film thickness and uniformity. Using atomic force microscopy in 70% ethanol, we present a novel and effective method to determine plasmid DNA film thickness and uniformity that combines height histograms and force-distance curves. We also investigate film deposition with DNA intercalated with 1,3-diaminopropane (Dap) on tantalum-coated substrates as a convenient and cost-effective alternative to the previously-used graphite substrate. The tantalum substrate permits deposition of films very similar to those formed on graphite. Using these refinements and further optimizations of the experimental procedure, we measure an absolute cross section of (7.4 ± 2.3) × 10−18 cm2 per nucleotide for conformational damage to a 3197 base-pair plasmid, induced by 10 eV electrons, which we believe should be considered as a reference value.
Practical formula for the shear viscosity of Yukawa fluids
Authors: Khrapak Sergey
Published: October 2018

A simple practical formula for the shear viscosity coefficient of Yukawa fluids is presented. This formula allows estimation of the shear viscosity in a very extended range of temperatures, from the melting point to ≃ 100 times the melting temperature. It demonstrates reasonable agreement with the available results from molecular dynamics simulations. Some aspects of the temperature dependence of the shear viscosity and diffusion coefficients on approaching the fluid-solid phase transition are discussed.
Wide range doping control and defect characterization of GaN layers with various Mg concentrations
Authors: Tetsuo Narita , Nobuyuki Ikarashi , Kazuyoshi Tomita , Keita Kataoka , Tetsu Kachi
Published: October 2018

We demonstrated a wide range of magnesium (Mg) doping control (1016–1020 cm−3) in a GaN layer grown by metalorganic vapor phase epitaxy on a freestanding GaN substrate and investigated the defect states at low and high Mg concentrations ([Mg]). Hydrogen concentrations ([H]) in as-grown GaN samples showed a one-to-one relationship with [Mg] over the wide Mg doping range of 6 × 1016–3 × 1019 cm−3 due to the formation of Mg-H complexes but exhibited gaps between [Mg] and [H] at the low and the high ends of the doping range. At low [Mg], we found that [H] was in good agreement with the sum of [Mg] and carbon (C) concentrations, indicating the formation of C-H complexes. The acceptor concentration (Na) was significantly decreased for heavily Mg-doped samples with lower [H], while Na values close to [Mg] were obtained for samples having [H] close to [Mg]. These suggest that an Mg atom forming an Mg–H bond in the as-grown samples plays as an acceptor after annealing while an Mg atom not forming an Mg-H complex has other states. In the heavily Mg-doped layers, transmission electron microscopy (TEM) and scanning TEM (STEM) analyses showed that nano-scale defects are formed and that these defects are pyramidal inversion domains (IDs) with Mg segregation at the top (0001) boundary. We estimated the amount of segregated Mg atoms on the basis of our TEM-STEM analyses and concluded that most parts of the Mg atoms not forming Mg-H complexes are segregated at the ID boundaries.
Optimising porous silicon Bragg reflectors for narrow spectral resonances
Authors: Piya Ranjana , Gupta Bakul , Gooding J. Justin , Reece Peter J.
Published: October 2018

Achieving sharp spectral resonances in porous silicon based photonic structures is of significant practical importance for improving the accuracy of refractive index-based sensing in chemical and biochemical applications. Here, we show that by compensating for depth related heterogeneities in the etching conditions, we are able to reduce the porosity modulation in Bragg reflectors to below 1% and achieve absorption limited spectral widths of 7 nm in the visible part of the spectrum. Such narrowband Bragg reflectors provide markedly improved sensing capability for real-time monitoring of refractive index changes compared with reflectors with broader spectral features.
Wavefront steering of elastic shear vertical waves in solids via a composite-plate-based metasurface
Authors: Zhang Jun , Su Xiaoshi , Pennec Yan , Jing Yun , Liu Xiaofeng , Hu Ning
Published: October 2018

We report a novel approach to control the wavefronts of shear vertical (SV) waves in solids using metasurfaces constituted by a stacked array of composite plates, which are composed of two connecting parts made of different materials. The metasurfaces are connected at two ends to the half-space solids where the elastic SV waves propagate. The incident SV waves in the left half-space solid induce flexural waves in the composite plates and subsequently are converted back to SV waves in the right half-space solid. The time delay of flexural waves in each composite plate of the metasurfaces is tuned through the varying length of the two connecting components. To quantitatively evaluate the time delay in each composite plate, a theoretical model for analyzing the phase of the transmitted SV waves is developed based on the Mindlin plate theory. To control the SV waves at will, each composite plate in the metasurface is delicately designed according to the proposed theoretical model. For illustrative purposes, two metasurfaces are designed and numerically validated.
Waiting time between charging and discharging processes in molecular junctions
Authors: Kosov Daniel S.
Published: October 2018

When electric current flows through a molecular junction, the molecule constantly charges and discharges by tunneling electrons. These charging and discharging events occur at specific but random times and are separated by stochastic time intervals. These time intervals can be associated with the dwelling time for a charge (electron or hole) to reside on the molecule. In this paper, the statistical properties of these time intervals are studied and a general formula for their distribution is derived. The theory is based on the Markovian master equation which takes into account transitions between the vibrational states of charged and neutral molecules in the junction. Two quantum jump operators are identified from the Liouvillian of the master equation—one corresponds to charging of the molecule and the other discharges the molecule back to the neutral state. The quantum jump operators define the conditional probability that given that the molecule was charged by a tunneling electron at time t, the molecule becomes neutral at a later time t + τ discharging the electron to the drain electrode. Statistical properties of these time intervals τ are studied with the use of this distribution.
Facile process to clean PMMA residue on graphene using KrF laser annealing
Authors: Hwang Hyeon Jun , Lee Yongsu , Cho Chunhum , Lee Byoung Hun
Published: October 2018

Persistent PMMA residue formed during a graphene transfer has been a culprit in the optimization of graphene device performance. We demonstrated a facile process to remove the PMMA residue using pulsed KrF laser annealing system at H2/Ar ambient. 10min laser annealing at 248nm could remove the PMMA residue as well as the methoxy and carboxyl function groups without causing noticeable damage to the graphene.
On the effect of parallel shear flow on the plasmoid instability
Authors: Hosseinpour M. , Chen Y. , Zenitani S.
Published: October 2018

The effect of symmetric sheared plasma flow parallel to the equilibrium magnetic field on the evolution of plasmoid instability is investigated by using two-dimensional MHD simulations. It is shown that as the velocity amplitude of a shear flow increases from sub-Alfvénic to the level of super-Alfvénic, the current sheet is stabilized against the plasmoid instability. Suppression of plasmoid instability also takes place for a sub-Alfvénic shear flow, provided that the shear length is sufficiently small compared to the magnetic shear. Therefore, an initially elongated thin current sheet with a Lundquist number greater than the critical value does not necessarily guarantee the development of the plasmoid instability. As a result, the Kelvin-Helmholtz (KH) instability is triggered. Although the rate of reconnection is quite fast in the nonlinear regime of the plasmoid instability, the reconnection of twisted field lines during the KH instability is very slow.
Aspartoacylase: a central nervous system enzyme. Structure, catalytic activity and regulation mechanisms
Authors: Kots Ekaterina D. , Khrenova Maria G. , Nemukhin Alexander V. , Varfolomeev Sergei D.
Published: October 2018

Aspartoacylase is a key enzyme in the human central nervous system. Catalytic deficiency of aspartoacylase is associated with several neurodegenerative disorders, which accounts for the enhanced interest in description of the catalytic action and regulatory mechanisms of this enzyme. This review focuses on molecular modelling of the catalytic function of aspartoacylase and the ways of its allosteric regulation in terms of modern theoretical chemistry approaches. The conclusions based on experimental data on the structure and functions of aspartoacylase accumulated during the last 20 years and conclusions drawn from computer modelling results of the last 5 years are analyzed in detail.

The bibliography includes 109 references.
An ethnobotanical study of traditional steam-bathing by the Batak people of North Sumatra, Indonesia
Authors: Silalahi Marina , Nisyawati
Published: October 2018

This study aimed to document (1) the Batak people’s knowledge of the use of medicinal plants for steam-bathing, (2) the preparation and operation of steam-bathing, and (3) the benefits of steam-bathing. To attain these objectives, data were collected by using ethnobotanical survey and interview methods. The survey was conducted in Kabanjahe and Berastagi traditional markets, in Kaban Tua village, and in Tanjung Julu village. The participants for the interview were nine medicinal plants traders, nine midwives, and 32 mothers. The basic principle of steam-bathing by the Batak people is based on thermotherapy and aromatherapy. A total of 59 species (belonging to 37 genera and to 25 families) have been documented as medicinal plants for their use as steam-bathing materials by the Batak people. The traders, midwives and mothers are all aware of the benefits of steam-bathing. Gaultheria leucocarpa Blume and Cinnamomum porrectum (Roxb.), the species that produce distinctive aromas and reduce pain, would be interesting to study for their phytochemical and pharmacological properties.
Towards mechanisms and standardization in extracellular vesicle and extracellular RNA studies: results of a worldwide survey
Authors: Soekmadji Carolina , Hill Andrew F. , Wauben Marca H. , Buzás Edit I. , Di Vizio Dolores , Gardiner Chris , Lötvall Jan , Sahoo Susmita , Witwer Kenneth W.
Published: October 2018

The discovery that extracellular vesicles (EVs) can transfer functional extracellular RNAs (exRNAs) between cells opened new avenues into the study of EVs in health and disease. Growing interest in EV RNAs and other forms of exRNA has given rise to research programmes including but not limited to the Extracellular RNA Communication Consortium (ERCC) of the US National Institutes of Health. In 2017, the International Society for Extracellular Vesicles (ISEV) administered a survey focusing on EVs and exRNA to canvass‐related views and perceived needs of the EV research community. Here, we report the results of this survey. Overall, respondents emphasized opportunities for technical developments, unraveling of molecular mechanisms and standardization of methodologies to increase understanding of the important roles of exRNAs in the broader context of EV science. In conclusion, although exRNA biology is a relatively recent emphasis in the EV field, it has driven considerable interest and resource commitment. The ISEV community looks forward to continuing developments in the science of exRNA and EVs, but without excluding other important molecular constituents of EVs.
Rsp5 Ubiquitin ligase–mediated quality control system clears membrane proteins mistargeted to the vacuole membrane
Authors: Sardana Richa , Zhu Lu , Emr Scott D.
Published: October 2018

Maintenance of organelle identity is profoundly dependent on the coordination between correct targeting of proteins and removal of mistargeted and damaged proteins. This task is mediated by organelle-specific protein quality control (QC) systems. In yeast, the endocytosis and QC of most plasma membrane (PM) proteins requires the Rsp5 ubiquitin ligase and ART adaptor network. We show that intracellular adaptors of Rsp5, Ear1, and Ssh4 mediate recognition and vacuolar degradation of PM proteins that escape or bypass PM QC systems. This second tier of surveillance helps to maintain cell integrity upon heat stress and protects from proteotoxicity. To understand the mechanism of the recognition of aberrant PM cargos by Ssh4–Rsp5, we mistarget multiple PM proteins de novo to the vacuolar membrane. We found that Ssh4–Rsp5 can target and ubiquitinate multiple lysines within a restricted distance from the membrane, providing a fail-safe mechanism for a diverse cargo repertoire. The mistargeting or misfolding of PM proteins likely exposes these lysines or shifts them into the “ubiquitination zone” accessible to the Ssh4–Rsp5 complex.
A Daily Diary Study of Rumination and Health Behaviors: Modeling Moderators and Mediators
Authors: Riley Kristen E , Park Crystal L , Laurenceau Jean-Philippe
Published: October 2018

Objective

Rumination, thinking about a negative mood repetitively, is a common cognitive process that may affect health behavior engagement or avoidance. Little research has examined relations between rumination and health behaviors.

Purpose

We aimed to test links between rumination and health behaviors as well as possible moderators and mediators of those links.

Methods

We used an 11-day online daily diary design. Health behavior outcomes included fruit intake, vegetable intake, exercise, alcohol intake, sexual risk taking behavior, and cigarette smoking.

Results

Rumination was related to alcohol intake at the within-person level. Using multivariate modeling, we found that significant within-person mediators for rumination to health behaviors included impulsivity, amotivation, self control, and using health behaviors as coping, with each of these mediating relationships for one to four out of the five health behavior outcomes. A significant between-person moderator includes perceived behavioral control for alcohol intake only, and intention was not a significant moderator of the rumination to health behavior relationships.

Conclusions

Rumination affects various maladaptive health behaviors differentially, through a number of mechanisms and under a moderating condition whereby those who feel more control are better able to buffer rumination’s deleterious effects. Future interventions can apply the results to individual and multiple behavior change interventions for chronic disease prevention, especially for those who are particularly suffering from ruminative thoughts.
3. Sympathetic spectators
Authors: Berry Christopher J.
Published: October 2018

Adam Smith published The Theory of Moral Sentiments in 1759. What the book sets out to do is investigate or analyse how, in practice, judgments and decisions about what is right or wrong are made. ‘Sympathetic spectators’ first discusses empiricism, a particular tradition of moral philosophy that was especially strong in Scotland. It goes on to consider the views of Francis Hutcheson and David Hume on moral sense and sympathy. It then examines Smith’s thoughts on sociality, morality, negotiated discord, self-interest, the impartial spectator and conscience (an internalized standard or benchmark of what is right or wrong), relativism, and moral judgment.
4. Living virtuously
Authors: Berry Christopher J.
Published: October 2018

Does someone deserve to be praised or punished? Can one individual merit owning more resources than another? Can blame be rightly attached to unintended actions? These are examples of moral questions that arise in everyday life. The Moral Sentiments is an ‘analysis of the principles’ that govern or underlie judgments of human conduct and character. ‘Living virtuously’ considers Adam Smith’s views on justice, benevolence, prudence, and other virtues. It is a central plank in Smith’s overall philosophy that individuals in a commercial society are able to act justly, prudently, and benevolently. There is no divergence between the ‘moral’ and ‘economic’ aspects of his thought.
7. Legacy and reputation
Authors: Berry Christopher J.
Published: October 2018

‘Legacy and reputation’ considers historical and contemporary views of the Wealth of Nations and why Adam Smith is ritually referred to as the ‘father of economics’. Ever since the Wealth of Nations was published it has been interpreted differently. Karl Marx, his most influential reader on the Left, both praised and damned him. Smith’s principles are central to the ‘free market model’ associated with the ‘New Right’. However, a more accurate picture of Smith’s legacy is his contribution to liberalism. For Smith, what is valuable about liberty is that it makes possible the greater public good. The true public good (the real wealth of nations) lies in the world of material well-being.
7. Into the 21st century
Authors: Burns Tom
Published: October 2018

‘Into the 21st century’ explains how there is an increased focus on how our body, and not just the brain, influences our mental health. Rapidly advancing computer technology, including artificial intelligence and virtual reality, is beginning to provide new treatment possibilities, not just support and simplify the old ones. The development of sophisticated imaging has supercharged the area of neurosciences and the increased understanding of genetics and the new science of epigenetics provide psychiatry with greater tools to identify and manage mental illnesses. A paradox with our increasingly technological and scientific advances is that the core dilemmas of psychiatry appear not to be diminishing. Psychiatry will survive the 21st century, but certainly it is changing.
Introduction
Authors: Bell David A.
Published: October 2018

The story of Napoleon’s life runs from his birth on Corsica in 1769 to his death in exile on Saint Helena in 1821, stretching beyond his death to include posthumous battles over his reputation. It is the story of a man with genuinely extraordinary personal qualities and involves some of the most dramatic events in history. The Introduction explains the story cannot be understood without placing Napoleon in the broader context of his age—both the historical changes that made him possible and the historical forces that he so powerfully grasped hold of. Napoleon’s entire story took place against the background of the French Revolution, which paved the way for his astonishing career.
Association Between Maternal Iodine Intake in Pregnancy and Childhood Neurodevelopment at Age 18 Months
Authors: Zhou Shao J , Condo Dominique , Ryan Philip , Skeaff Sheila A , Howell Stuart , Anderson Peter J , McPhee Andrew J , Makrides Maria
Published: October 2018

There are limited and inconsistent data suggesting that mild iodine deficiency in pregnancy might be associated with poorer developmental outcomes in children. Between 2011 and 2015, we conducted a prospective cohort study in Australia examining the relationship between maternal iodine intake in pregnancy and childhood neurodevelopment, assessed using Bayley Scales of Infant and Toddler Development, Third Edition (Bayley-III), in 699 children at 18 months. Maternal iodine intake and urinary iodine concentration (UIC) were assessed at study entry (<20 weeks’ gestation) and at 28 weeks’ gestation. Maternal iodine intake in the lowest (<220 μg/day) or highest (≥391 μg/day) quartile was associated with lower cognitive, language, and motor scores (mean differences ranged from 2.4 (95% confidence interval (CI): 0.01, 4.8) to 7.0 (95% CI: 2.8, 11.1) points lower) and higher odds (odds ratios ranged from 2.7 (95% CI: 1.3, 5.6) to 2.8 (95% CI: 1.3, 5.7)) of cognitive developmental delay (Bayley-III score <1 standard deviation) compared with mothers with an iodine intake in the middle quartiles. There was no association between UIC in pregnancy and Bayley-III outcomes regardless of whether UIC and the outcomes were analyzed as continuous or categorical variables. Both low and high iodine intakes in pregnancy were associated with poorer childhood neurodevelopment in this iodine-sufficient population.