bluuebunny/crossref_metadata_2025 huggingface dataset:
“Where is Dementia?” A Systematic Literature Review Exploring Neuroanatomical Aspects of Dementia
Authors: Oh Chorong , LaPointe Leonard
Published: September 2017

Dementia is a condition caused by and associated with separate physical changes in the brain. The signs and symptoms of dementia are very similar across the diverse types, and it is difficult to diagnose the category by behavioral symptoms alone. Diagnostic criteria have relied on a constellation of signs and symptoms, but it is critical to understand the neuroanatomical differences among the dementias for a more precise diagnosis and subsequent management. With this regard, this review aims to explore the neuroanatomical aspects of dementia to better understand the nature of distinctive subtypes, signs, and symptoms. This is a review of English language literature published from 1996 to the present day of peer-reviewed academic and medical journal articles that report on older people with dementia. This review examines typical neuroanatomical aspects of dementia and reinforces the importance of a thorough understanding of the neuroanatomical characteristics of the different types of dementia and the differential diagnosis of them.
Design of high‐gain dual‐band dual‐circular‐polarised antenna using reflective metasurface
Authors: Mao Chenyang , Yang Yang , He Xiaoxiang , Zheng Jingming , Liu Ting
Published: September 2017

A novel design of high‐gain dual‐band dual‐circular‐polarised antenna loaded with reflective metasurface is proposed. The proposed antenna consists of a linear‐polarised coplanar waveguide antenna with a polarisation‐switched metasurface structure. The metasurface is composed of 25 unit cells arranged in a 5 × 5 layout and each unit cell is a pair of symmetrical semi‐circle loop with a diagonal microstrip, which is designed to adjust the axial ratio for dual‐band circular polarisation. Simulated result shows that the impedance bandwidth of the proposed antenna is about 63% from 3.8 to 7.3 GHz, and the average boresight gain has a great enhancement of about 4 dBi. The proposed antenna possesses the characteristic of right‐handed circular polarisation from 4.15 to 4.45 GHz, while the left‐handed circular polarisation is from 5.75 to 6.4 GHz. The simulated and measured results are in good agreement so that the performance of the proposed antenna can be confirmed.
Quantisation‐free binary feature aggregation for fast image representation
Authors: Lee S. , Yang H.S.
Published: September 2017

A method for aggregating binary features to represent an image in a single vector is proposed. Binary features are decomposed into several sub‐features to permit the individual aggregation of each sub‐feature into a histogram. The method is completely quantisation‐free, enabling exceptionally fast image representation. Experimental results demonstrate that the method is a competitive alternative for image representation when runtime efficiency is crucial.
645‐GHz InP heterojunction bipolar transistor harmonic oscillator
Authors: Yun J. , Kim J. , Yoon D. , Rieh J.‐S.
Published: September 2017

645‐GHz signal generation with a harmonic oscillator based on a 250‐nm InP heterojunction bipolar transistor technology is demonstrated. The oscillator is based on the common‐base cross‐coupled topology, generating a second harmonic signal through the push–push operation. The fabricated oscillator exhibits oscillation frequencies ranging from 561.5 to 645.1 GHz with bias variation. The measured peak output power is –17.4 dBm with a dc power dissipation of 49.3 mW (dc‐to‐RF efficiency of 0.04%). Additionally, terahertz imaging was successfully demonstrated with the developed oscillator employed as a signal source.
Mainlobe interference suppression via transmit phase codes optimisation in MIMO radar systems
Authors: Zehua Yu , Jun Li , Yuhong Zhang , Guisheng Liao
Published: September 2017

Recent studies allow mainlobe interference suppression in MIMO radar systems by weighting the random phase codes at transmitter. However, the performance of interference suppression is not stable when the phase codes are generated randomly, especially in the case of the small number of the elements or a large number of interferences. A transmit phase codes optimisation method is proposed. The modified transmit steering vector is constructed by combining the transmit phase codes and the steering vector of the expected signal. The problem can be solved by minimising the projection of the modified transmit steering vector onto the interference subspace. Simulations verify the effectiveness of this method.
On the impact of current generation commercial gallium nitride power transistors on power converter loss
Authors: Petersen A. , Stone D.A. , Foster M.P.
Published: September 2017

The enormous potential benefits of gallium nitride based power switching devices, only commercially available very recently, in terms of power switching device loss are highlighted. This is first demonstrated through a simulated prediction of loss in multilevel converters, followed by experimental validation. While the simulations focus on losses in multilevel converters, the observations made are relevant in a broad range of applications.
A novel multiobjective generation and transmission investment framework for implementing 100% renewable energy sources
Authors: Bagheri Abed , Vahidinasab Vahid , Mehran Kamyar
Published: September 2017

Over the last decade, it has been considerable attempts to replace thermal power plants by renewable energy sources (RESs), mainly to reduce harmful gaseous emissions. Ubiquitous nature of these sources in the emerging smart grid, demands a dominated RES power system for a long‐term horizon. This study proposed a model for 100% RES‐based system which is tractable and flexible enough to be used for any mixture of generation unit types with any level of uncertainty needless of the correlation between their random and unpredictable behaviours. To overcome the complex nature of RESs, an efficient stochastic multiobjective mixed‐integer linear programming framework is proposed. The efficacy of the proposed model is evaluated via numerical simulation.
RWG MoM‐via‐locally corrected Nyström method in near‐field to far‐field transformation using very‐near‐field measurement
Authors: Rafiee Alavi Rezvan , Kiaee Ali , Mirzavand Rashid , Mousavi Pedram
Published: September 2017

Locally corrected Nyström (LCN) method is used to solve electric field integral equations (EFIE) of the equivalent current method in the planar very‐near‐field measurement of antennas and RF circuits. The exact relationship between the Rao–Wilton–Glisson (RWG) method of moments and first‐order and zero‐order LCN is established for both magnetic and electric currents to ensure normal current continuity between adjacent triangular patches. The proposed method is a point‐based RWG discretisation of EFIE and causes a noticeable decrease in the degree of freedom. It consequently eliminates spurious charges and significantly lowers the condition number of the impedance matrix. Moreover, it is more efficient to be accelerated by fast algorithms such as multi‐level fast multipole method. In what follows, the detailed explanation of the proposed method, along with the examples of current reconstruction and antenna far‐field calculation, is presented.
Enhanced cognition‐driven formulation of space mapping for equal‐ripple optimisation of microwave filters
Authors: Zhang Chao , Feng Feng , Zhang Qi‐Jun , Bandler John W.
Published: September 2017

A recently introduced cognition‐driven formulation of space mapping (SM) is an efficient method for equal‐ripple optimisation of microwave filters. Feature frequency parameters and ripple height parameters are utilised. The technique requires the assumption that the initial number of feature parameters is correct, and uses an equally divided passband specification as a preliminary target. The present study proposes an enhanced technique which can correct the number of feature frequency parameters, thus it can work well even if the filter response of the initial point has an incorrect number of feature frequency parameters. Additionally, the enhanced technique incorporates filter design knowledge of the Chebyshev filter function into cognition‐driven SM. The authors propose to use the feature frequency parameters of the Chebyshev filter function response curve to obtain the target for cognition‐driven SM. A new trust region mechanism handles new parameters in the proposed process of correcting the number of feature frequency parameters and guarantees convergence. The technique is suitable for the design of filters with equal‐ripple responses. It is illustrated by two microwave filter examples.
Hybrid Tikhonov source current reconstruction method for large‐scale problems
Authors: Bod Mohammad , Sarraf Reza , Moradi Gholamreza , Jafargholi Amir , Moallemizadeh Amir
Published: September 2017

Source current reconstruction method (SRM) is a field transformation technique in which the equivalent currents at the antenna aperture are reconstructed from the known radiated fields. To stabilise SRM equations and reduce the effect of measurement errors and noise, the Tikhonov SRM has been frequently used. However, finding the regularisation parameter and solving the Tikhonov SRM equation have a high computational cost especially for large‐scale problems or in the presence of both electric and magnetic currents. Here, a hybrid regularised least‐square minimum residual (LSMR) technique is proposed to implement the Tikhonov SRM equation. In this method, the Tikhonov SRM is applied on the Krylov subspace that is created by the LSMR iterative solver. The regularisation parameter of the hybrid Tikhonov equation is determined at each iteration of the projected problem with the generalised cross‐validation method. Results of current reconstruction and near‐field/far‐field transformation with the proposed hybrid Tikhonov SRM are reported in this study and compared with the standard Tikhonov SRM. It is shown in both simulation and measurement examples that a significant improvement in the computational cost is realised with the proposed hybrid method while all of the benefits of the traditional method are preserved.
DC offset minimisation of three‐phase multilevel inverter configuration under fault and DC link voltage unbalance conditions
Authors: Airineni Madhukar Rao , Keerthipati Sivakumar
Published: September 2017

In recent days, multilevel inverters are quite popular in the photovoltaic system to improve the power quality. One of the popular multilevel inverters for medium power applications is neutral point clamping inverter. However, with the limited number of switching combinations, energy balancing and fault‐tolerant operation is a major issue. The absence of energy balance mechanism may lead to unequal charge and discharge patterns in the batteries used in off‐grid applications, which in turn results in the un‐equal voltage at the batteries terminals. The difference in voltage between the sources can introduce the DC voltage offset at AC output, which causes serious problems when fed to the transformers or inductive loads like the induction motor. To address this problem, a five‐level inverter is proposed which is capable of energy balancing between the two DC sources, minimising the DC voltage offset and able to operate in some fault‐tolerant conditions. At the same time, this topology uses less number of switches as compared to conventional three‐phase five‐level inverters. The proposed topology is developed by combining conventional two‐level and three‐level inverters. The topology is verified by simulation using Matlab Simulink and tested on a laboratory prototype. The control algorithm for prototype is implemented with the help of Xilinx SPARTAN‐6 (XC6SLX9) FPGA board.
Snap‐back free shorted‐anode super‐junction TCIGBT
Authors: Luo Peng , Sweet Mark , Narayanan Ekkanath Madathil Sankara
Published: September 2017

A novel structure called the shorted‐anode super‐junction trench clustered insulated gate bipolar transistor (SA‐SJ‐TCIGBT) is proposed and demonstrated through numerical simulations in 1.2 kV, field‐stop technology. This device is based on the SJ‐TCIGBT concept. In the SA‐SJ‐TCIGBT structure, due to the introduction of a segmented n+‐anode, the device can operate in both forward conducting mode and freewheeling diode mode without any snap back in the current–voltage characteristics. In comparison to the SJ‐TCIGBT structure, the proposed device shows significant improvement in trade‐off relationship between forward voltage drop and switch off energy losses. Simulation results show that 25% decrease in switching energy losses can be achieved. Moreover, the tail current is effectively reduced without any increase in the overshoot voltage. Detailed two‐dimensional modelling of the structure shows that significant amount of excess electrons are extracted through the SA structure during turn‐off process.
Parameter tuning of the PLL to consider the effect on power system small‐signal angular stability
Authors: Du Wenjuan , Chen Xiao , Wang Haifeng
Published: September 2017

A phase locked loop (PLL) tracks the phase of the terminal voltage of a grid‐connected permanent magnetic synchronous generator (PMSG) for wind power generation. Phase tracking by the PLL is used by the vector control for the grid connection of the PMSG. This study investigates the impact of phase‐tracking performance of the PLL on power system small‐signal angular stability. Damping torque analysis conducted in this study explains why the impact of the PLL is normally small. The analysis indicates that under the special condition of open‐loop modal resonance, however, the effect of the PLL may become significant. It is very likely that the open‐loop modal resonance may reduce the power system small‐signal angular stability. Hence, in tuning the parameters of the PLL, the open‐loop modal resonance should be avoided. In this study, the procedure about the parameter tuning of the PLL to consider the effect of open‐loop modal resonance is proposed and demonstrated in an example multi‐machine power system integrated with a PMSG. Analysis and conclusions made in this study are evaluated using the example power system.
Parameter estimation and suppression for DRFM‐based interrupted sampling repeater jammer
Authors: Zhou Chao , Liu Quanhua , Chen Xinliang
Published: September 2017

By partial interception and multiple forwarding of a radar transmitting signal, digital radio frequency memory‐based interrupted sampling repeater jamming can yield a partial processing gain and form multiple false target groups in the range direction, achieving jamming effects of both suppression and deception. Various improved jamming strategies have been proposed, while jamming suppression problems have not been fully addressed. In this study, a jamming suppression method based on the idea of ‘reconstruction and cancellation’ is proposed by analysing the jamming principle. The method firstly analyses the pulse compression results with time‐frequency analysis to obtain the intercepted slice number and forwarding times; then, the slice width is estimated by deconvolution processing; finally, iterative cancellation is used to suppress the jamming. Performance of the method was verified by Monte Carlo simulation. The results show that the normalised error of the slice width estimation is <5% when the jamming‐to‐noise ratio reaches 15 dB (after pulse compress); the cancellation method can effectively restrain the jamming by bringing an improvement of signal‐to‐jamming ratio >16 dB.
Biallelic Mutations in SLC1A2; an Additional Mode of Inheritance for SLC1A2-Related Epilepsy
Authors: Gusic Mirjana , Günthner Roman , Alhaddad Bader , Kovacs-Nagy Reka , Makowski Christine , Baumeister Friedrich , Strom Tim , Meitinger Thomas , Prokisch Holger , Wortmann Saskia , Wagner Matias
Published: September 2017

Recently, heterozygous de novo mutations in SCL1A2 have been reported to underlie severe early-onset epileptic encephalopathy. In one male presenting with epileptic seizures and visual impairment, we identified a novel homozygous splicing variant in SCL1A2 (c.1421 + 1G > C) by using exome sequencing. Functional studies on cDNA level confirmed a consecutive loss of function. Our findings suggest that not only de novo mutations but also biallelic variants in SLC1A2 can cause epilepsy and that there is an additional autosomal recessive mode of inheritance. These findings also contribute to the understanding of the genetic mechanism of autosomal dominant SLC1A2-related epileptic encephalopathy as they exclude haploinsufficiency as exclusive genetic mechanism.
Do Knee Bracing and Delayed Weight Bearing Affect Mid-Term Functional Outcome after Anterior Cruciate Ligament Reconstruction?
Authors: Di Miceli Riccardo , Marambio Carlotta , Zati Alessandro , Monesi Roberta , Benedetti Maria
Published: September 2017

Purpose The aim of this study was to assess the effect of knee bracing and timing of full weight bearing after anterior cruciate ligament reconstruction (ACLR) on functional outcomes at mid-term follow-up.

Methods We performed a retrospective study on 41 patients with ACLR. Patients were divided in two groups: ACLR group, who received isolated ACL reconstruction and ACLR-OI group who received ACL reconstruction and adjunctive surgery. Information about age at surgery, bracing, full or progressive weight bearing permission after surgery were collected for the two groups. Subjective IKDC score was obtained at follow-up. Statistical analysis was performed to compare the two groups for IKDC score. Subgroup analysis was performed to assess the effect of postoperative regimen (knee bracing and weight bearing) on functional outcomes.

Results The mean age of patients was 30.8 ± 10.6 years. Mean IKDC score was 87.4 ± 13.9. The mean follow-up was 3.5 ± 1.8 years. Twenty-two (53.7%) patients underwent ACLR only, while 19 (46.3%) also received other interventions, such as meniscal repair and/or collateral ligament suture. Analysis of overall data showed no differences between the groups for IKDC score. Patients in the ACLR group exhibited a significantly better IKDC score when no brace and full weight bearing after 4 weeks from surgery was prescribed in comparison with patients who worn a brace and had delayed full weight bearing. No differences were found with respect to the use of brace and postoperative weight bearing regimen in the ACLR-OI group.

Conclusion Brace and delayed weight bearing after ACLR have a negative influence on long-term functional outcomes. Further research is required to explore possible differences in the patients operated on ACLR and other intervention with respect to the use of a brace and the timing of full weight bearing to identify optimal recovery strategies.

Level of Evidence Level III, retrospective observational study.
Centralized Pediatric Surgery in the Nordic Countries: A Role Model for Europe?
Authors: Bjørland Kristin , Qvist Niels , Wester Tomas , Pakarinen Mikko
Published: September 2017

Nearly all neonatal surgical conditions are classified as rare diseases in Europe. Due to rapidly developing treatment modalities and novel surgical techniques, as well as increasing demands from patients, there is a growing need for centralization of advanced pediatric surgical care. However, the optimal way to concentrate pediatric surgical experience in each country remains unclear and depends on multiple national features, such as size and distribution of the population, geographical distances, local surgical expertise, organization of the health care system, and political agendas. This review outlines the current practices to concentrate on specialized pediatric surgery in different Nordic countries.
Design of co-existence parallel periodic surface structure induced by picosecond laser pulses on the Al/Ti multilayers
Authors: Petrović Suzana , Peruško D. , Kovač J. , Panjan P. , Mitrić M. , Pjević D. , Kovačević A. , Jelenković B.
Published: September 2017

Formation of periodic nanostructures on the Ti/5x(Al/Ti)/Si multilayers induced by picosecond laser pulses is studied in order to better understand the formation of a laser-induced periodic surface structure (LIPSS). At fluence slightly below the ablation threshold, the formation of low spatial frequency-LIPSS (LSFL) oriented perpendicular to the direction of the laser polarization is observed on the irradiated area. Prolonged irradiation while scanning results in the formation of a high spatial frequency-LIPSS (HSFL), on top of the LSFLs, creating a co-existence parallel periodic structure. HSFL was oriented parallel to the incident laser polarization. Intermixing between the Al and Ti layers with the formation of Al-Ti intermetallic compounds was achieved during the irradiation. The intermetallic region was formed mostly within the heat affected zone of the sample. Surface segregation of aluminium with partial ablation of the top layer of titanium was followed by the formation of an ultra-thin Al2O3 film on the surface of the multi-layered structure.
Equivalence of the EMD- and NEMD-based decomposition of thermal conductivity into microscopic building blocks
Authors: Matsubara Hiroki , Kikugawa Gota , Ishikiriyama Mamoru , Yamashita Seiji , Ohara Taku
Published: September 2017

Thermal conductivity of a material can be comprehended as being composed of microscopic building blocks relevant to the energy transfer due to a specific microscopic process or structure. The building block is called the partial thermal conductivity (PTC). The concept of PTC is essential to evaluate the contributions of various molecular mechanisms to heat conduction and has been providing detailed knowledge of the contribution. The PTC can be evaluated by equilibrium molecular dynamics (EMD) and non-equilibrium molecular dynamics (NEMD) in different manners: the EMD evaluation utilizes the autocorrelation of spontaneous heat fluxes in an equilibrium state whereas the NEMD one is based on stationary heat fluxes in a non-equilibrium state. However, it has not been fully discussed whether the two methods give the same PTC or not. In the present study, we formulate a Green-Kubo relation, which is necessary for EMD to calculate the PTCs equivalent to those by NEMD. Unlike the existing theories, our formulation is based on the local equilibrium hypothesis to describe a clear connection between EMD and NEMD simulations. The equivalence of the two derivations of PTCs is confirmed by the numerical results for liquid methane and butane. The present establishment of the EMD–NEMD correspondence makes the MD analysis of PTCs a robust way to clarify the microscopic origins of thermal conductivity.
Epitaxial fabrication of two-dimensional NiSe2 on Ni(111) substrate
Authors: Shao Yan , Song Shiru , Wu Xu , Qi Jing , Lu Hongliang , Liu Chen , Zhu Shiyu , Liu Zhongliu , Wang Jiaou , Shi Dongxia , Du Shixuan , Wang Yeliang , Gao H.-J.
Published: September 2017

Two-dimensional (2D) transition metal dichalcogenides (TMDs) receive significant attention due to their intriguing physical properties for both fundamental research and potential applications in electronics, optoelectronics, and catalysis. A high-quality 2D film of NiSe2, a TMD material, is grown epitaxially by a single step direct selenization of a Ni(111) substrate. X-ray photoemission spectroscopy, low-energy electron diffraction, scanning tunneling microscopy, and density functional theory calculations are combined to confirm the formation and structure of the film, revealing a (√3 × √3) superlattice of the NiSe2 film formed on the (√7 × √7) superlattice of the substrate. Fabrication of this 2D NiSe2 film opens opportunities to research its applications, especially for electrocatalysis and energy storage devices.
Ultrathin polarization-insensitive wide-angle broadband near-perfect absorber in the visible regime based on few-layer MoS2 films
Authors: Zhang Yuebian , Liu Wenwei , Li Zhancheng , Cheng Hua , Zhang Yanbang , Jia Guozhi , Chen Shuqi , Tian Jianguo
Published: September 2017

We report the design, characterization, and experimental demonstration of a broadband near-perfect absorber in the visible regime based on strong interference in ultrathin molybdenum disulfide films obtained by the spin-coating method. The absorber is polarization-insensitive, and the absorption peak maintains a high value for large angles of incidence, which provides more efficient absorption for nonpolarized or oblique incident beams. The experimental results show that the absorption can reach more than 87% between 400 nm and 640 nm, which is in reasonable agreement with the simulated results. This work may offer a further step in the development of solar absorption-based nano-optoelectronic devices.
Epitaxial growth of BaTiO3/ZnO heterojunctions and transition from rectification to bipolar resistive switching effect
Authors: Jia Caihong , Yin Xiaoqian , Yang Guang , Wu Yonghui , Li Jiachen , Chen Yonghai , Zhang Weifeng
Published: September 2017

Epitaxial BaTiO3/ZnO heterojunctions have been grown on a-plane Al2O3 by pulsed laser deposition. The out-of-plane and in-plane epitaxial relationships of BTO/ZnO/Al2O3 are determined to be (100)BTO//(0002)ZnO//(112¯0)Al2O3 and [011]BTO//[21¯1¯0]ZnO//[0001]Al2O3, respectively. A three-domain-epitaxy growth mode was found to coexist in BaTiO3 films, while ZnO was a single domain epitaxially grown on a-Al2O3. A rectification effect was observed for the BTO films grown at high laser energies of 450 and 320 mJ, while bipolar resistive switching was found for those BTO films grown at low laser energies of 280 and 200 mJ. The transition from the rectification effect to the bipolar resistive switching effect can be understood by the variance of interface state density.
Steering of SH wave propagation in electrorheological elastomer with a structured meta-slab by tunable phase discontinuities
Authors: Xu Yanlong , Li Yi , Cao Liyun , Yang Zhichun , Zhou Xiaoling
Published: September 2017

The generalized Snell’s law (GSL) with phase discontinuity proposed based on the concept of a metasurface, which can be used to control arbitrarily the reflection and refraction of waves, attracts a growing attention in these years. The concept of abnormally deflecting the incident wave has been applied to the elastic field very recently. However, most of the studies on metasurfaces are based on passive materials, which restricts the frequency or the deflected angles always working in a single state. Here, we steer elastic SH wave propagation in an electrorheological (ER) elastomer with a structured meta-slab composed of geometrically periodic wave guides by exposing the slab to the programmed electric fields. The dependence of phase velocities of SH waves on the applied electric fields can make the phase shift under the form of a special function along the slab, which will control the refraction angles of the transmitted SH waves by the GSL. Accordingly we design the meta-slab theoretically and conduct corresponding numerical simulations. The results demonstrate that the structured meta-slab under the programmed external electric fields can deflect SH wave flexibly with tunable refraction angles and working frequencies, and can focus SH wave with tunable focal lengths. The present study will broaden the scope of applying adaptive materials to design metasurfaces with tunability.
Study of pseudo soldering based on eddy current pulsed thermography
Authors: Zhou Xiuyun , Xue Yun , Chen Yaqiu , Lu Xiaochuan , Liu Zhen
Published: September 2017

Pseudo soldering defects can break the electrical and mechanical connection between components and the print circuit board and eventually cause failure of the whole electronic equipment. In this letter, the eddy current pulsed thermography (ECPT) method was used for defect inspection of small-sized solder joints. The identification of defects of solder joints is based on the heat transfer between various component structures. The experimental results indicated that the ECPT method can be effectively used for defect detection and location of the solder joints. In addition, it can distinguish different degrees of pseudo soldering.
Plasmonic effect in Au(core)-CdS(shell) quantum dot-sensitized photoelectrochemical cell for hydrogen generation from water
Authors: Ikeda Takuya , Akashi Ryo , Fujishima Musashi , Tada Hiroaki
Published: September 2017

UV-light irradiation of Au nanoparticle (NP)-loaded mesoporous TiO2 nanocrystalline films in an ethanol solution of Cd(NO3)2 and S8 at 298 K gives rise to selective CdS deposition on Au NPs to yield Au(core)-CdS(shell) hybrid quantum dots (Au@CdS/mp-TiO2). Two-electrode quantum dot-sensitized photoelectrochemical cells with the structure of photoanode|0.25 M Na2S, 0.35 M Na2SO3 (solvent = water)|cathode were fabricated. The Au@CdS/mp-TiO2 photoanode cell yields hydrogen (H2) with a rate of 0.18 ml h−1 [solar-to-current efficiency (STCE) = 0.028%] without external bias far surpassing the rate of 0.028 ml h−1 (solar-to-current efficiency = 0.006%) for the CdS/mp-TiO2 photoanode cell under illumination of simulated sunlight (λ > 430 nm, AM 1.5, one sun). The 3D finite-difference time-domain calculations for a model Au@CdS/TiO2 system indicate that an intense local electric field with an enhancement factor of ∼103 is generated at the Au-CdS-TiO2 three-phase interface. The striking effect of the Au core stems from the enhancement of the excitation of the CdS shell and subsequent charge separation by the intense local electric field.
Normal and reverse defect annealing in ion implanted II-VI oxide semiconductors
Authors: Azarov Alexander , Galeckas Augustinas , Wendler Elke , Ellingsen Josef , Monakhov Edouard , Svensson Bengt G.
Published: September 2017

Post-implantation annealing is typically used to remove structural defects and electrically activate implanted dopants in semiconductors. However, ion-induced defects and their interaction with dopants in group II oxide semiconductors are not fully understood. Here, we study defect evolution in the course of annealing in CdO and ZnO materials implanted with nitrogen which is one of the most promising candidates for p-type doping. The results of photoluminescence and ion channeling measurements revealed a striking difference in defect behavior between CdO and ZnO. In particular, the defect annealing in CdO exhibits a two stage behavior, the first stage accounting for efficient removal of point defects and small defect clusters, while the second one involves gradual disappearance of extended defects where the sample decomposition can play a role. In contrast, a strong reverse annealing occurs for ZnO with a maximum defect concentration around 900 °C. This effect occurs exclusively for nitrogen ions and is attributed to efficient growth of extended defects promoted by the presence of nitrogen.
Atomic layer deposition of aluminum fluoride using Al(CH3)3 and SF6 plasma
Authors: Vos M. F. J. , Knoops H. C. M. , Synowicki R. A. , Kessels W. M. M. , Mackus A. J. M.
Published: September 2017

Metal fluorides typically have a low refractive index and a very high transparency and find many applications in optical and optoelectronic devices. Nearly stoichiometric, high-purity AlF3 films were deposited by atomic layer deposition (ALD) using trimethylaluminum [Al(CH3)3] and SF6 plasma. Self-limiting growth was confirmed and the growth per cycle was determined to range from 1.50 Å to 0.55 Å for deposition temperatures between 50 °C and 300 °C. In addition, the film density of ∼2.8 g cm−3 was found to be relatively close to the bulk value of 3.1 g cm−3. Vacuum ultraviolet spectroscopic ellipsometry measurements over the wavelength range of 140–2275 nm showed a refractive index n of 1.35 at 633 nm, and an extinction coefficient k of <10−4 above 300 nm, for all deposition temperatures. Optical emission spectroscopy during the SF6 plasma exposure step of the ALD cycle revealed the formation of C2H2 and CF2 species, resulting from the interaction of the plasma with the surface after Al(CH3)3 exposure. On the basis of these results, a reaction mechanism is proposed in which F radicals from the SF6 plasma participate in the surface reactions. Overall, this work demonstrates that SF6 plasma is a promising co-reactant for ALD of metal fluorides, providing an alternative to co-reactants such as metal fluorides, HF, or HF-pyridine.
Single molecule translocation in smectics illustrates the challenge for time-mapping in simulations on multiple scales
Authors: Mukherjee Biswaroop , Peter Christine , Kremer Kurt
Published: September 2017

Understanding the connections between the characteristic dynamical time scales associated with a coarse-grained (CG) and a detailed representation is central to the applicability of the coarse-graining methods to understand molecular processes. The process of coarse graining leads to an accelerated dynamics, owing to the smoothening of the underlying free-energy landscapes. Often a single time-mapping factor is used to relate the time scales associated with the two representations. We critically examine this idea using a model system ideally suited for this purpose. Single molecular transport properties are studied via molecular dynamics simulations of the CG and atomistic representations of a liquid crystalline, azobenzene containing mesogen, simulated in the smectic and the isotropic phases. The out-of-plane dynamics in the smectic phase occurs via molecular hops from one smectic layer to the next. Hopping can occur via two mechanisms, with and without significant reorientation. The out-of-plane transport can be understood as a superposition of two (one associated with each mode of transport) independent continuous time random walks for which a single time-mapping factor would be rather inadequate. A comparison of the free-energy surfaces, relevant to the out-of-plane transport, qualitatively supports the above observations. Thus, this work underlines the need for building CG models that exhibit both structural and dynamical consistency to the underlying atomistic model.
Dielectric breakdown field of strained silicon under hydrostatic pressure
Authors: Kim Chiho , Ramprasad Rampi
Published: September 2017

First-principles density functional theory calculations are used to reveal a quantitative relationship between the dielectric breakdown field and hydrostatic pressure of crystalline Si. The electronic band structure, phonon dispersion, and electron scattering rate are computed for pressures from 62.2 kbar (compressive) to -45.6 kbar (tensile) to estimate the rate of kinetic energy gain and loss for the electron. The theoretical dielectric breakdown fields are then determined using the von Hippel–Fröhlich criterion. Compressive stresses lead to a lower breakdown field, while significant increases in the dielectric breakdown field can be achieved by tensile stresses.
Poly(sodium 4-styrenseulfonate)-modified monolayer graphene for anode applications of organic photovoltaic cells
Authors: Zhou Yongfang , Wang Min , Wang Liang , Liu Shuli , Chen Shufen , Cao Kun , Shang Wenjuan , Mai Jiangquan , Zhao Baomin , Feng Jing , Lu Xinhui , Huang Wei
Published: September 2017

An insulated poly(sodium 4-styrenseulfonate) (PSS) was used to modify monolayer graphene for anode applications of organic photovoltaics (OPVs). With this PSS interfacial modification layer, the OPVs showed a significant increase of 56.4% in efficiency due to an improved work function and hydrophilic feature of graphene and an enlarged recombination resistance of carriers/excitons. Doping a highly contorted 1,2,5-thiadiazole-fused 12-ring polyaromatic hydrocarbon into the active layer to form ternary blended OPVs further enlarged the recombination resistance of carriers/excitons and improved light absorption of the active layer, with which a high power conversion efficiency of 6.29% was acquired.
Effect of barrier layer on switching polarity of ZrO2-based conducting-bridge random access memory
Authors: Chandrasekaran Sridhar , Simanjuntak Firman Mangasa , Tsai Tsung-Ling , Lin Chun-An , Tseng Tseung-Yuen
Published: September 2017

In this study, metal diffusion barrier-dependent switching polarity in ZrO2-based conducting-bridge random access memory was investigated. The device without the barrier layer (BL) exhibited nonpolar switching characteristics. However, inserting TiW BL resulted in positive reset failure. This phenomenon depends on the size and shape of the conducting bridge and also on the defects that contribute to the formation and rupture of the bridge. Consequently, the properties of the conducting bridge govern the device switching performance. Cu- and oxygen vacancy-based conducting bridge during N-Set for a device with and without the BL was proposed. The effect of the insertion of BL on the switching performance was also discussed. The absence of BL resulted in switching instability and poor nonvolatility. By contrast, a device with BL exhibited enhanced uniformity and nonvolatility, and the retention was more than 105 s at 200 °C.
Neutralization of acidic drainage by Cryptococcus sp. T1 immobilized in alginate beads
Authors: Okai Masahiko , Suwa Chisato , Nagaoka Shintaro , Obara Nobuo , Mitsuya Daisuke , Kurihara Ayako , Ishida Masami , Urano Naoto
Published: September 2017

We isolated Cryptococcus sp. T1 from Lake Tazawa’s acidic water in Japan. Cryptococcus sp. T1 neutralized an acidic casamino acid solution (pH 3.0) and released ammonia from the casamino acids to aid the neutralization. The neutralization volume was estimated to be approximately 0.4 mL/h. The casamino acids’ amino acids decreased (1.24→0.15 mM); ammonia increased (0.22→0.99 mM). We neutralized acidic drainage water (1 L) from a Tamagawa River neutralization plant, which was run through the column with the T1-immobilized alginate beads at a flow rate of 0.5 mL/min, and observed that the viscosity, particle size and amounts of the alginate beads affected the acidic drainage neutralization with an increase of the pH value from 5.26 to 6.61 in the last fraction. An increase in the Al concentration decreased Cryptococcus sp. T1’s neutralization ability. After 48 h, the pH of acidic water with 50 mg/L Al was apparently lower than that without Al. Almost no pH increase was observed at 75 mg/L.
A user-centered, iterative engineering approach for advanced biomass cookstove design and development
Authors: Shan Ming , Carter Ellison , Baumgartner Jill , Deng Mengsi , Clark Sierra , Schauer James J , Ezzati Majid , Li Jiarong , Fu Yu , Yang Xudong
Published: September 2017

Unclean combustion of solid fuel for cooking and other household energy needs leads to severe household air pollution and adverse health impacts in adults and children. Replacing traditional solid fuel stoves with high efficiency, low-polluting semi-gasifier stoves can potentially contribute to addressing this global problem. The success of semi-gasifier cookstove implementation initiatives depends not only on the technical performance and safety of the stove, but also the compatibility of the stove design with local cooking practices, the needs and preferences of stove users, and community economic structures. Many past stove design initiatives have failed to address one or more of these dimensions during the design process, resulting in failure of stoves to achieve long-term, exclusive use and market penetration. This study presents a user-centered, iterative engineering design approach to developing a semi-gasifier biomass cookstove for rural Chinese homes. Our approach places equal emphasis on stove performance and meeting the preferences of individuals most likely to adopt the clean stove technology. Five stove prototypes were iteratively developed following energy market and policy evaluation, laboratory and field evaluations of stove performance and user experience, and direct interactions with stove users. The most current stove prototype achieved high performance in the field on thermal efficiency (ISO Tier 3) and pollutant emissions (ISO Tier 4), and was received favorably by rural households in the Sichuan province of Southwest China. Among household cooks receiving the final prototype of the intervention stove, 88% reported lighting and using it at least once. At five months post-intervention, the semi-gasifier stoves were used at least once on an average of 68% [95% CI: 43, 93] of days. Our proposed design strategy can be applied to other stove development initiatives in China and other countries.
𝐙/𝐦-graded Lie algebras and perverse sheaves, II
Authors: Lusztig George , Yun Zhiwei
Published: September 2017

We consider a fixed block for the equivariant perverse sheaves with nilpotent support on the 1-graded component of a semisimple cyclically graded Lie algebra. We give a combinatorial parametrization of the simple objects in that block.
The Role of El Niño Southern Oscillation in Commodity Price Movement and Predictability
Authors: Ubilava David
Published: September 2017

El Niño Southern Oscillation (ENSO) impacts the supply of and, to some extent, the demand for primary commodities. But what are the consequences of ENSO shocks for these commodity price dynamics? I consider monthly series of 43 primary commodity prices and sea surface temperature (SST) anomalies in the Niño3.4 region from January 1980 to December 2016. The SST anomalies serve as a proxy for ENSO, as persistent positive (negative) SST deviations from their historical mean are associated with El Niño (La Niña) events. I apply a time‐varying smooth transition autoregressive modeling framework to account for potentially complex dynamic relationships between SST anomalies and prices. The estimated models reveal more amplified price responses during El Niño events, and at the onset of the ENSO cycle. I find statistically significant linkages between SST anomalies and a subset of agricultural commodity prices, which manifests in a better price forecasting for the commodities produced in the tropics. While I also find some in‐sample evidence for prices of selected nonagricultural commodities, for example, timber and metals, the ability of SST anomalies to predict these commodity prices in an out‐of‐sample setting is lacking. These findings carry important welfare implications, especially for developing economies that have been historically linked to the behavior of primary commodity prices, and offer valuable insights to policy makers working in areas related to economic growth and foreign aid programs, as well as those concerned with issues of farm income and rural poverty.
CGmapTools improves the precision of heterozygous SNV calls and supports allele-specific methylation detection and visualization in bisulfite-sequencing data
Authors: Guo Weilong , Zhu Ping , Pellegrini Matteo , Zhang Michael Q , Wang Xiangfeng , Ni Zhongfu
Published: September 2017

Motivation

DNA methylation is important for gene silencing and imprinting in both plants and animals. Recent advances in bisulfite sequencing allow detection of single nucleotide variations (SNVs) achieving high sensitivity, but accurately identifying heterozygous SNVs from partially C-to-T converted sequences remains challenging.

Results

We designed two methods, BayesWC and BinomWC, that substantially improved the precision of heterozygous SNV calls from ∼80% to 99% while retaining comparable recalls. With these SNV calls, we provided functions for allele-specific DNA methylation (ASM) analysis and visualizing the methylation status on reads. Applying ASM analysis to a previous dataset, we found that an average of 1.5% of investigated regions showed allelic methylation, which were significantly enriched in transposon elements and likely to be shared by the same cell-type. A dynamic fragment strategy was utilized for DMR analysis in low-coverage data and was able to find differentially methylated regions (DMRs) related to key genes involved in tumorigenesis using a public cancer dataset. Finally, we integrated 40 applications into the software package CGmapTools to analyze DNA methylomes. This package uses CGmap as the format interface, and designs binary formats to reduce the file size and support fast data retrieval, and can be applied for context-wise, gene-wise, bin-wise, region-wise and sample-wise analyses and visualizations.

Availability and implementation

The CGmapTools software is freely available at https://cgmaptools.github.io/.

Supplementary information

Supplementary data are available at Bioinformatics online.
Logarithmic Ramifications of Étale Sheaves by Restricting to Curves
Authors: Hu Haoyu
Published: September 2017

In this article, we prove that the Swan conductor of an étale sheaf on a smooth variety defined by Abbes and Saito’s logarithmic ramification theory can be computed by its classical Swan conductors after restricting it to curves. It extends the main result of Barrientos [7] for rank $1$ sheaves. As an application, we give a logarithmic ramification version of generalizations of Deligne and Laumon’s lower semi-continuity property for Swan conductors of étale sheaves on relative curves to higher relative dimensions in a geometric situation.
Creating a Consumable Past: How Memory Making Shapes Marketization
Authors: Brunk Katja H , Giesler Markus , Hartmann Benjamin J
Published: September 2017

Consumer researchers tend to equate successful marketization—the transition from a socialist to a capitalist economy—with the consensual acquiescence to an idealized definition of the socialist past. For this reason, little research has examined how memories about socialism influence marketization over time. To redress this gap, we bring prior consumer research on commercial mythmaking and popular memory to bear on an in-depth analysis of the marketization of the former German Democratic Republic. We find that, owing to a progressive sequence of conflicts between commercialized memories of socialism promoted by marketing agents and countermemories advocating socialism as a political alternative, definitions of the past, and by extension, capitalism’s hegemony are subject to ongoing contestation and change. Our theoretical framework of hegemonic memory making explains relationships among consumption, memory making, and market systems that have not been recognized by prior research on consumption and nostalgia.
Decrease in Seminal HIV-1 RNA Load After Praziquantel Treatment of Urogenital Schistosomiasis Coinfection in HIV-Positive Men—An Observational Study
Authors: Midzi Nicholas , Mduluza Takafira , Mudenge Boniface , Foldager Leslie , Leutscher Peter D C
Published: September 2017

Background

Urogenital schistosomiasis due to Schistosoma hematobium infection is hypothesized to cause increased HIV-1 RNA shedding in semen in HIV co-infected men as result of chronic egg-induced inflammation in the prostate and the seminal vesicles. The effect of treatment with the antihelminthic agent praziquantel on seminal HIV-1 RNA load was assessed in this study.

Methods

HIV-1 RNA load was determined in blood plasma and semen at baseline and at 10-week follow-up. Praziquantel was administered at baseline and two weeks later.

Results

Eighteen HIV-positive men with S. haematobium co-infection were enrolled into the study. Status of antiretroviral therapy (ART): 6 ART-naïve and 12 ART-experienced. All participants became egg-negative in urine at follow-up. Among the ART-naïve men, the mean HIV-1 RNA load decreased by 0.32 log10 copies per mL (4.41 vs 4.09) in blood plasma from baseline to follow-up, and in semen by 1.06 log10 copies per mL (4.06 vs 3.00).

Conclusions

This study demonstrated a decline in seminal HIV-1 RNA load following praziquantel treatment of urogenital schistosomiasis infection in HIV-positive men. The finding needs further exploration in a larger randomized study targeting praziquantel as a supplementary preventive measure of sexual transmission of HIV-1 in S. haematobium endemic areas in sub-Saharan Africa.