bluuebunny/crossref_metadata_2025 huggingface dataset:
Magnetic-flux-driven topological quantum phase transition and manipulation of perfect edge states in graphene tube
Authors: Lin S. , Zhang G. , Li C. , Song Z.
Published: August 2016

We study the tight-binding model for a graphene tube with perimeter N threaded by a magnetic field. We show exactly that this model has different nontrivial topological phases as the flux changes. The winding number, as an indicator of topological quantum phase transition (QPT) fixes at N/3 if N/3 equals to its integer part [N/3], otherwise it jumps between [N/3] and [N/3] + 1 periodically as the flux varies a flux quantum. For an open tube with zigzag boundary condition, exact edge states are obtained. There exist two perfect midgap edge states, in which the particle is completely located at the boundary, even for a tube with finite length. The threading flux can be employed to control the quantum states: transferring the perfect edge state from one end to the other, or generating maximal entanglement between them.
Tyrosine phosphorylation and protein degradation control the transcriptional activity of WRKY involved in benzylisoquinoline alkaloid biosynthesis
Authors: Yamada Yasuyuki , Sato Fumihiko
Published: August 2016

Benzylisoquinoline alkaloids (BIQ) are among the most structurally diverse and pharmaceutically valuable secondary metabolites. A plant-specific WRKY-type transcription factor, CjWRKY1, was isolated from Coptis japonica and identified as a transcriptional activator of BIQ biosynthesis. However, the expression of CjWRKY1 gene alone was not sufficient for the activation of genes encoding biosynthetic enzymes. Here, we report the importance of post-translational regulation of CjWRKY1 in BIQ biosynthesis. First, we detected the differential accumulation of CjWRKY1 protein in two cell lines with similar CjWRKY1 gene expression but different levels of accumulated alkaloids. Further investigation of the WRKY protein identified the phosphorylation of the WRKYGQK core domain at Y115. The CjWRKYY115E phosphorylation-mimic mutant showed loss of nuclear localization, DNA-binding activity and transactivation activity compared to wild-type CjWRKY1. Rapid degradation of the CjWRKY1 protein was also confirmed following treatment with inhibitors of the 26S proteasome and protease inhibitors. The existence of two independent degradation pathways as well as protein phosphorylation suggests the fine-tuning of CjWRKY1 activities is involved in the regulation of biosynthesis of BIQs.
Modulation of IL-6 induced RANKL expression in arthritic synovium by a transcription factor SOX5
Authors: Feng Xiaoke , Shi Yumeng , Xu Lingxiao , Peng Qiuyue , Wang Fang , Wang Xiaoxi , Sun Wei , Lu Yan , Tsao Betty P. , Zhang Miaojia , Tan Wenfeng
Published: August 2016

Receptor activator of nuclear factor κB ligand (RANKL) is critically involved in bone erosion of rheumatoid arthritis (RA). We previously reported association between younger age at onset of RA and a RANKL promoter SNP that conferred an elevated promoter activity via binding to a transcription factor SOX5. Here we study the regulation of SOX5 levels in relation to RANKL expression in RA synovial fibroblasts (SF) and the development of bone erosion in the collagen-induced arthritis (CIA) mouse. Our data indicated SOX5 levels were higher in synovium and synovial fluid from RA compared to osteoarthritis patients. Pro-inflammatory cytokines upregulated SOX5 and RANKL expression in both primary RA SF and the rheumatoid synovial fibroblast cell line, MH7A. Overexpression of SOX5 resulted in significantly increased RANKL levels, while knockdown of SOX5 resulted in diminished IL-6 mediated RANKL upregulation in MH7A cells. Chromatin immunoprecipitation (ChIP) showed approximately 3-fold enrichment of RANKL-specific DNA in anti-SOX5 immunoprecipitate in IL-6 treated MH7A cells as compared to untreated cells. Locally silencing SOX5 gene significantly diminished RANKL positive cells and bone erosion in CIA mice. These findings suggest SOX5 is an important regulator of IL-6-induced RANKL expression in RA SF.
Analysis of Photoluminescence Thermal Quenching: Guidance for the Design of Highly Effective p-type Doping of Nitrides
Authors: Liu Zhiqiang , Huang Yang , Yi Xiaoyan , Fu Binglei , Yuan Guodong , Wang Junxi , Li Jinmin , Zhang Yong
Published: August 2016

A contact-free diagnostic technique for examining position of the impurity energy level of p-type dopants in nitride semiconductors was proposed based on photoluminescence thermal quenching. The Mg ionization energy was extracted by the phenomenological rate-equation model we developed. The diagnostic technique and analysis model reported here are priorities for the design of highly effective p-doping of nitrides and could also be used to explain the abnormal and seldom analyzed low characteristic temperature T0 (about 100 K) of thermal quenching in p-type nitrides systems. An In-Mg co-doped GaN system is given as an example to prove the validity of our methods. Furthermore, a hole concentration as high as 1.94 × 1018 cm−3 was achieved through In-Mg co-doping, which is nearly one order of magnitude higher than typically obtained in our lab.
The Role of Prostate Apoptosis Response-4 (Par-4) in Mycobacterium tuberculosis Infected Macrophages
Authors: Han Ji-Ye , Lim Yun-Ji , Choi Ji-Ae , Lee Jung-hwan , Jo Sung-Hee , Oh Sung-Man , Song Chang-Hwa
Published: August 2016

Prostate apoptosis response-4 (Par-4) is a tumor suppressor protein that forms a complex with glucose-regulated protein 78 (GRP78) to induce apoptosis. Previously, we reported that ER stress-induced apoptosis is a critical host defense mechanism against Mycobacterium tuberculosis (Mtb). We sought to understand the role of Par-4 during ER stress-induced apoptosis in response to mycobacterial infection. Par-4 and GRP78 protein levels increased in response Mtb (strain: H37Ra) infection. Furthermore, Par-4 and GRP78 translocate to the surface of Mtb H37Ra-infected macrophages and induce apoptosis via caspase activation. NF-κB activation, Mtb-mediated ER stress, and Par-4 production were significantly diminished in macrophages with inhibited ROS production. To test Par-4 function during mycobacterial infection, we analyzed intracellular survival of Mtb H37Ra in macrophages with Par-4 overexpression or knockdown. Mtb H37Ra growth was significantly reduced in Par-4 overexpressing macrophages and increased in knockdown macrophages. We also observed increased Par-4, GRP78, and caspases activation in Bacillus Calmette-Guérin (BCG)-infected prostate cancer cells. Our data demonstrate that Par-4 is associated with ER stress-induced apoptosis resulting in reduced intracellular survival of mycobacteria. BCG treatment increases Par-4-dependent caspase activation in prostate cancer cells. These results suggest ER stress-induced Par-4 acts as an important defense mechanism against mycobacterial infection and regulates cancer.
Characterization of a novel low-temperature-active, alkaline and sucrose-tolerant invertase
Authors: Zhou Junpei , He Limei , Gao Yajie , Han Nanyu , Zhang Rui , Wu Qian , Li Junjun , Tang Xianghua , Xu Bo , Ding Junmei , Huang Zunxi
Published: August 2016

A glycoside hydrolase family 32 invertase from Bacillus sp. HJ14 was expressed in Escherichia coli. The purified recombinant enzyme (rInvHJ14) showed typical biochemical properties of low-temperature-active and alkaline enzymes: (i) rInvHJ14 was active and stable in the range of pH 7.0–9.5 with an apparent pH optimum of 8.0; (ii) rInvHJ14 was most active but not stable at 30–32.5 °C, with 19.7, 48.2 and 82.1% of its maximum activity when assayed at 0, 10 and 20 °C, respectively and the Ea, ΔG* (30 °C), Km (30 °C) and kcat (30 °C) values for hydrolysis of sucrose by rInvHJ14 was 47.6 kJ mol−1, 57.6 kJ mol−1, 62.9 mM and 746.2 s−1, respectively. The enzyme also showed strong sucrose tolerance. rInvHJ14 preserved approximately 50% of its highest activity in the presence of 2045.0 mM sucrose. Furthermore, potential factors for low-temperature-active and alkaline adaptations of rInvHJ14 were presumed. Compared with more thermostable homologs, rInvHJ14 has a higher frequency of glycine residues and a longer loop but a lower frequency of proline residues (especially in a loop) in the catalytic domain. The catalytic pockets of acid invertases were almost negatively charged while that of alkaline rInvHJ14 was mostly positively charged.
Welding of silver nanowire networks via flash white light and UV-C irradiation for highly conductive and reliable transparent electrodes
Authors: Chung Wan-Ho , Kim Sang-Ho , Kim Hak-Sung
Published: August 2016

In this work, silver nanowire inks with hydroxypropyl methylcellulose (HPMC) binders were coated on polyethylene terephthalate (PET) substrates and welded via flash white light and ultraviolet C (UV-C) irradiation to produce highly conductive transparent electrodes. The coated silver nanowire films were firmly welded and embedded into PET substrate successfully at room temperature and under ambient conditions using an in-house flash white light welding system and UV-C irradiation. The effects of light irradiation conditions (light energy, irradiation time, pulse duration and pulse number) on the silver nanowire networks were studied and optimized. Bending fatigue tests were also conducted to characterize the reliability of the welded transparent conductive silver nanowire films. The surfaces of the welded silver nanowire films were analyzed via scanning electron microscopy (SEM), while the transmittance of the structures was measured using a spectrophotometer. From the results, a highly conductive and transparent silver nanowire film with excellent reliability could be achieved at room temperature under ambient conditions via the combined flash white light and UV-C irradiation welding process.
New route for hollow materials
Authors: Rivaldo-Gómez C. M. , Ferreira F. F. , Landi G. T. , Souza J. A.
Published: August 2016

Hollow micro/nano structures form an important family of functional materials. We have used the thermal oxidation process combined with the passage of electric current during a structural phase transition to disclose a colossal mass diffusion transfer of Ti ions. This combination points to a new route for fabrication of hollow materials. A structural phase transition at high temperature prepares the stage by giving mobility to Ti ions and releasing vacancies to the system. The electric current then drives an inward delocalization of vacancies, condensing into voids and finally turning into a big hollow. This strong physical phenomenon leading to a colossal mass transfer through ionic diffusion is suggested to be driven by a combination of phase transition and electrical current followed by chemical reaction. We show this phenomenon for Ti leading to TiO2 microtube formation, but we believe that it can be used to other metals undergoing structural phase transition at high temperatures.
Dicer ablation in osteoblasts by Runx2 driven cre-loxP recombination affects bone integrity, but not glucocorticoid-induced suppression of bone formation
Authors: Liu Peng , Baumgart Mario , Groth Marco , Wittmann Jürgen , Jäck Hans-Martin , Platzer Matthias , Tuckermann Jan P. , Baschant Ulrike
Published: August 2016

Glucocorticoid-induced osteoporosis (GIO) is one of the major side effects of long-term glucocorticoid (GC) therapy mediated mainly via the suppression of bone formation and osteoblast differentiation independently of GC receptor (GR) dimerization. Since microRNAs play a critical role in osteoblast differentiation processes, we investigated the role of Dicer dependent microRNAs in the GC-induced suppression of osteoblast differentiation. MicroRNA sequencing of dexamethasone-treated wild-type and GR dimer-deficient mesenchymal stromal cells revealed GC-controlled miRNA expression in a GR dimer-dependent and GR dimer-independent manner. To determine the functional relevance of mature miRNAs in GC-induced osteoblast suppression, mice with an osteoblast-specific deletion of Dicer (DicerRunx2Cre) were exposed to glucocorticoids. In vitro generated Dicer-deficient osteoblasts were treated with dexamethasone and analyzed for proliferation, differentiation and mineralization capacity. In vivo, abrogation of Dicer-dependent miRNA biogenesis in osteoblasts led to growth retardation and impaired bone formation. However, subjecting these mice to GIO showed that bone formation was similar reduced in DicerRunx2Cre mice and littermate control mice upon GC treatment. In line, differentiation of Dicer deficient osteoblasts was suppressed to the same extent as wild type cells by GC treatment. Therefore, Dicer-dependent small RNA biogenesis in osteoblasts plays only a minor role in the pathogenesis of GC-induced inhibition of bone formation.
Microwave-Assisted Plant Extraction Processes
Authors: Mato Chaín Rafael B. , Monzó-Cabrera Juan , Solyom Katalin
Published: August 2016

Microwaves, as oscillating electromagnetic fields, are the perfect choice for rapid heating of dipolar molecules like water, and are thus of special interest in extraction processes for plant matrices. Volumetric microwave heating, in combination with solvent effects, can alter or damage cell structures, improving the extraction of compounds of interest. As a result, the enhanced extraction kinetics lead to more efficient processes, use less chemicals, have shorter extraction times, and provide higher extraction yields. This chapter aims to review the basic theory of microwave processing, providing useful information on the interaction between the plant matrix and the electromagnetic field, and the available bench-, pilot-, and industrial-scale applications. In addition, different microwave-assisted extraction strategies are outlined, together with a detailed description of the main process variables.
Prospects of Magnetic Nanoparticles for Magnetic Field-Assisted Mixing of Fluids with Relevance to Chemical Engineering
Authors: Boroun Shahab , Larachi Faïçal
Published: August 2016

Utilization of efficient, safe and controllable alternative energization approaches towards green and sustainable processes is vigorously explored in the field of process intensification. In this contribution, magnetic fields are specifically discussed and possible mechanisms to exploit this form of energy excitation for fluid-phase mixing in confined spaces are introduced. Magnetic nanofluids are par excellence the most suitable media for transmission of magnetic energy into a target fluid. In addition, their benign nature makes them suitable candidates for biological applications in microfluidics. The interaction of magnetic fluids with magnetic fields, as governed by the equations of motion in ferrohydrodynamics, can generate different mechanisms for fluidic actuations. These mechanisms are mainly the result of the type of magnetic field enabled, e.g., non-uniform static, oscillating or rotating magnetic fields, their strength or the magnetization of polar fluids, in addition to the momentum exchange induced between the rotating magnetic nanoparticles and the carrier fluid in rotating magnetic fields. With an emphasis on applications in microfluidic devices, the review of recent advances in the present contribution shows how such a variety of magnetic fields can be taken advantage of to mix fluids. Mixing in electrically conducting fluids in the framework of magnetohydrodynamics, as another class of magnetic field-assisted mixing is also another subject of this review. This latter category benefits from the absence of magnetic nanoparticles but on the other hand requires complex structuring of mixing devices as imposed by indispensable and appropriate interactions between electric and magnetic fields. The reviewed research findings in this category show how the generation of complex fluid motions is attainable specifically in micron-sized conduits.
Fluorogenic bidirectional displacement probe-based real-time isothermal DNA amplification and specific visual detection of products
Authors: Ding Xiong , Wang Guoping , Sun Jingjing , Zhang Tao , Mu Ying
Published: August 2016

We report an easy-to-design probe as both the primer and the indicator to mediate isothermal DNA amplification with high sensitivity and specificity.
35Cl dynamic nuclear polarization solid-state NMR of active pharmaceutical ingredients
Authors: Hirsh David A. , Rossini Aaron J. , Emsley Lyndon , Schurko Robert W.
Published: August 2016

In this work, we show how to obtain efficient dynamic nuclear polarization (DNP) enhanced 35Cl solid-state NMR (SSNMR) spectra at 9.4 T and demonstrate how they can be used to characterize the molecular-level structure of hydrochloride salts of active pharmaceutical ingredients (APIs) in both bulk and low wt% API dosage forms.
Potential applications of polyoxometalates for the discrimination of human papillomavirus in different subtypes
Authors: Zhang Teng , Fu Ding-Yi , Wu Yuqing , Wang Yizhan , Wu Lixin
Published: August 2016

Application of a europium decatungstate (EuW10) to discriminate between peptides from different subtypes of HPV capsid proteins.
Coordination versatility of p-hydroquinone-functionalized dibenzobarrelene-based PC(sp3)P pincer ligands
Authors: De-Botton Sophie , Romm Ronit , Bensoussan Guillaume , Hitrik Maria , Musa Sanaa , Gelman Dmitri
Published: August 2016

Bifunctional hydroquinone-based PC(sp3)P pincer complexes.
Architectural evolution of phase domains in shape memory polyurethanes by dissipative particle dynamics simulations
Authors: Hu Jinlian , Zhang Cuili , Li Xun , Han Jianping , Ji Fenglong
Published: August 2016

The MDI phase in SMPUs develops a framework with netpoints evolving from spheres, to linked-spheres, linked-cylinders, and then to linked-bi-crossing-cylinders.
Lecanicillones A–C, three dimeric isomers of spiciferone A with a cyclobutane ring from an entomopathogenic fungus Lecanicillium sp. PR-M-3
Authors: Wang Zai-Ying , Sang Xia-Nan , Sun Ke , Huang Sheng-Dong , Chen Sheng-Shuang , Xue Chun-Mei , Ban Lan-Feng , Li Zhan-Lin , Hua Hui-Ming , Pei Yue-Hu , Bai Jiao
Published: August 2016

Lecanicillones A–C (1–3), three unusual dimeric spiciferones with a cyclobutane ringvia[2 + 2] cycloaddition, were isolated from an entomopathogenic fungusLecanicilliumsp. PR-M-3.
Sensitive profiling of phenols, bile acids, sterols, and eicosanoids in mammalian urine by large volume direct injection-online solid phase extraction-ultra high performance liquid chromatography-polarity switching tandem mass spectrometry
Authors: Liu Yao , Song Qingqing , Zheng Jiao , Li Jun , Zhao Yunfang , Li Chun , Song Yuelin , Tu Pengfei
Published: August 2016

A new sensitive LVDI-online SPE-UHPLC-psMS/MS method was developed and applied for simultaneous and direct determination of 28 constituents, including 10 BAs, 5 sterols, 8 eicosanoids and 8 phenolic compounds in mammalian urinary samples.
Valorization of coffee bean waste: a coffee bean waste derived multifunctional catalyst for photocatalytic hydrogen production and electrocatalytic oxygen reduction reactions
Authors: Unni Sreekuttan M. , George Leena , Bhange Siddheshwar N. , Devi R. Nandini , Kurungot Sreekumar
Published: August 2016

The valorization of coffee bean waste (CBW) by producing nitrogen doped porous carbon with photocatalytic and electrocatalytic properties using a silica templating method.
Hydrothermal synthesis, structural and luminescent properties of a Cr3+ doped MgGa2O4 near-infrared long lasting nanophospor
Authors: Mondal Amba , Das Sourav , Manam J.
Published: August 2016

A novel near infrared long lasting phosphor MgGa2O4:Cr3+ was successfully prepared by a hydrothermal method and a solid state reaction method.
Phase change modulated thermal switch and enhanced performance enabled by graphene coating
Authors: Ng Boon T. , Lim Zhi Y. , Hung Yew Mun , Tan Ming K.
Published: August 2016

A thermal switch based on the phase change of the liquid medium; thermal performance is improved substantially with graphene coating.
Fabrication of H3PW12O40/agarose membrane for catalytic production of biodiesel through esterification and transesterification
Authors: Hou Rui , Zhang Dan , Duan Xixin , Wang Xiaohong , Wang Shengtian , Sun Zhong
Published: August 2016

Heteropolyacids/agarose materials could be used in esterification and transesterification with higher efficiency and higher stability and duration in batch mode.
A novel highly dispersive magnetic nanocatalyst in water : glucose as an efficient and green ligand for the immobilization of copper(ii) for the cycloaddition of alkynes to azides
Authors: Moghaddam Firouz Matloubi , Saberi Vahid , Kalhor Sepideh , Ayati Seyed Ebrahim
Published: August 2016

A new heterogeneous and highly dispersive nanocatalyst in water was prepared by the immobilization of Cu2+ onto glucose on Fe3O4.
Cu-catalyzed sulfenylation of imidazol[1,2-a]pyridine via C–H functionalization using a combination of Na2S2O3 and halides
Authors: Ding Yingcai , Xie Ping , Zhu Wenhui , Xu Baojun , Zhao Wannian , Zhou Aihua
Published: August 2016

A copper-catalysed sulfenylation of 2-phenylimidazo[1,2-a]pyridine by using inorganic salt Na2S2O3 and alkyl halides (Cl, Br, I) or iodobenzene homologues via C–H functionalization process was reported here.
Highly sensitive biosensor based on the synergistic effect of Fe3O4–Co3O4 bimetallic oxides and graphene
Authors: Han Shanying , Du Tianyu , Lai Lanmei , Jiang Xuerui , Cheng Chuansheng , Jiang Hui , Wang Xuemei
Published: August 2016

Synergistic effect of Fe3O4–Co3O4 nanoparticles and reduced graphene oxide allows the sensitive electrochemical detection of dopamine and uric acid.
Role of (3-aminopropyl)tri alkoxysilanes in grafting of chlorosulphonic acid immobilized magnetic nanoparticles and their application as heterogeneous catalysts for the green synthesis of α-aminonitriles
Authors: Singh Harminder , Rajput Jaspreet Kaur , Arora Priya , Jigyasa Jigyasa
Published: August 2016

Grafting of SiO2@Fe3O4nanoparticles with alkoxysilanes for sulphamic acid functionalization and synthesis of α-aminonitriles at room temperature in water.
Influence of surfactants in forced dynamic dewetting
Authors: Henrich Franziska , Fell Daniela , Truszkowska Dorota , Weirich Marcel , Anyfantakis Manos , Nguyen Thi-Huong , Wagner Manfred , Auernhammer Günter K. , Butt Hans-Jürgen
Published: August 2016

Surfactants strongly decrease the dynamic receding contact angle even below the critical micelle concentration. The latter is the scaling parameter.
Non-covalent forces tune the electron transfer complex between ferredoxin and sulfite reductase to optimize enzymatic activity
Authors: Kim Ju Yaen , Kinoshita Misaki , Kume Satoshi , GT Hanke , Sugiki Toshihiko , Ladbury John E. , Kojima Chojiro , Ikegami Takahisa , Kurisu Genji , Goto Yuji , Hase Toshiharu , Lee Young-Ho
Published: August 2016

Although electrostatic interactions between negatively charged ferredoxin (Fd) and positively charged sulfite reductase (SiR) have been predominantly highlighted to characterize complex formation, the detailed nature of intermolecular forces remains to be fully elucidated. We investigated interprotein forces for the formation of an electron transfer complex between Fd and SiR and their relationship to SiR activity using various approaches over NaCl concentrations between 0 and 400 mM. Fd-dependent SiR activity assays revealed a bell-shaped activity curve with a maximum ∼40–70 mM NaCl and a reverse bell-shaped dependence of interprotein affinity. Meanwhile, intrinsic SiR activity, as measured in a methyl viologen-dependent assay, exhibited saturation above 100 mM NaCl. Thus, two assays suggested that interprotein interaction is crucial in controlling Fd-dependent SiR activity. Calorimetric analyses showed the monotonic decrease in interprotein affinity on increasing NaCl concentrations, distinguished from a reverse bell-shaped interprotein affinity observed from Fd-dependent SiR activity assay. Furthermore, Fd:SiR complex formation and interprotein affinity were thermodynamically adjusted by both enthalpy and entropy through electrostatic and non-electrostatic interactions. A residue-based NMR investigation on the addition of SiR to 15N-labeled Fd at the various NaCl concentrations also demonstrated that a combination of electrostatic and non-electrostatic forces stabilized the complex with similar interfaces and modulated the binding affinity and mode. Our findings elucidate that non-electrostatic forces are also essential for the formation and modulation of the Fd:SiR complex. We suggest that a complex configuration optimized for maximum enzymatic activity near physiological salt conditions is achieved by structural rearrangement through controlled non-covalent interprotein interactions.
Auditory Brainstem Response Thresholds to Air- and Bone-Conducted CE-Chirps in Neonates and Adults
Authors: Cobb Kensi M. , Stuart Andrew
Published: August 2016

Purpose

The purpose of this study was to compare auditory brainstem response (ABR) thresholds to air- and bone-conducted CE-Chirps in neonates and adults.

Method

Thirty-two neonates with no physical or neurologic challenges and 20 adults with normal hearing participated. ABRs were acquired with a starting intensity of 30 dB normal hearing level (nHL). The lowest stimulus intensity level at which a wave V was identifiable and replicable was considered the ABR threshold.

Results

ABR thresholds to air-conducted CE-Chirps were 9.8 dB nHL for neonates and adults. ABR thresholds to bone-conducted CE-Chirps were 3.8 and 13.8 dB nHL for neonates and adults, respectively. The difference in ABR thresholds to bone-conducted CE-Chirps was significantly different (
p
< .0001, η
p
2
= .45). Adults had significantly larger wave V amplitudes to air- (
p
< .0001, η
p
2
= .50) and bone-conducted (
p
= .013, η
p
2
= .15) CE-Chirps at a stimulus intensity of 30 dB nHL. At the same intensity, adults evidenced significantly shorter wave V latencies (
p
< .0001, η
p
2
= .49) only with air-conducted CE-chirps.

Conclusion

The difference in ABR thresholds and wave V latencies to air- and bone-conducted CE-Chirps between neonates and adults may be attributed to a disparity in effective signal delivery to the cochlea.
Outage performance of MIMO cooperative networks with selective OFDMA relaying
Authors: Wang Jing , Zhang Yan
Published: August 2016

The multiple‐input multiple‐output (MIMO) cooperative networks with selective orthogonal frequency division multiplexing access (OFDMA) relaying, where transmit beamforming and maximum ratio combining are carried out at source transmission and destination reception, respectively, are considered. The closed‐form expression of outage probability is investigated to statistically assess the performance of systems. The impact of number of relays on the outage performance under arbitrary Nakagmi‐m fading channels is analysed. Results reveal that increasing the number of relays is not always necessary for the improvement of outage performance and there has been the right relay configuration to guarantee the outage performance and reduce the complexity for relay networks.
Influence factors in contamination process of XP‐160 insulators based on computational fluid mechanics
Authors: Zhang Zhijin , Zhang Wei , You Jinwei , Jiang Xingliang , Zhang Dongdong , Bi Maoqiang , Wu Bin , Wu Jian
Published: August 2016

Polluted insulators frequently face flashover accident and it threatens the safety and stability of power system. In order to help to reduce the occurrence of flashover, it is necessary to study the contamination characteristics of insulators and its influence factors. In this study, the contamination of insulator is simulated by the Eulerian multiphase model in computational fluid dynamics. The flow field around insulators is calculated and the volume fraction of the particle phase is used to characterise the pollution degree on insulator surface. Results show that the pollution is mainly distributed on windward side and leeward side of insulator. The crosswind side of insulator is slightly contaminated. The four influence factors, wind velocity, particle concentration, particle diameter and flow angle have different effects on insulator contamination. Among these factors the particle concentration contributes most to the whole contamination degree of insulators. A wind tunnel contamination test on insulator is carried out to verify the feasibility of the numerical simulation. It can be found that simulated contamination distribution and variation of contamination degree with wind velocity well coincide with the results of wind tunnel test. The numerical simulation in this study is practical in studying the insulator contamination.
Fast motion estimation algorithm using multilevel distortion search in Walsh–Hadamard domain
Authors: Dong Liang , Pan Zhibin
Published: August 2016

Block‐matching motion estimation (BME) can efficiently reduce the temporal redundancy between the successive video sequences in video compression coding system. In this study, a fast BME algorithm using multilevel distortion search in Walsh–Hadamard domain is proposed to reduce the computational burden and speed up coding process. First, the proposed algorithm divides the block into several sub‐blocks. Then, the Walsh–Hadamard transform is applied to these sub‐blocks. Finally, the proposed algorithm calculates the partial block matching distortion by utilising a novel back diagonal search scheme which can quickly reject unnecessary candidate block in a multilevel manner. Experimental results show that the proposed algorithm effectively reduces the number of operations in block distortion calculation meanwhile maintains the best motion estimation matching quality. Compared with the full search, the proposed algorithm can reduce 87.19% computational complexity without any degradation of the peak signal to noise ratio. In addition, compared with the partial distortion search algorithm, successive elimination algorithm, multilevel successive elimination algorithm and the transform‐domain successive elimination algorithm, the proposed algorithm can also save 68.27, 70.09, 37.81 and 37.44% computational complexity, respectively. Moreover, the proposed algorithm can also be easily incorporated into any block‐based template search motion estimation algorithm.
Prediction of the containment of HIV infection by antiretroviral therapy – a variable structure control approach
Authors: Anelone Anet J.N. , Spurgeon Sarah K.
Published: August 2016

It is demonstrated that the reachability paradigm from variable structure control theory is a suitable framework to monitor and predict the progression of the human immunodeficiency virus (HIV) infection following initiation of antiretroviral therapy (ART). A manifold is selected which characterises the infection‐free steady‐state. A model of HIV infection together with an associated reachability analysis is used to formulate a dynamical condition for the containment of HIV infection on the manifold. This condition is tested using data from two different HIV clinical trials which contain measurements of the CD4+ T cell count and HIV load in the peripheral blood collected from HIV infected individuals for the six month period following initiation of ART. The biological rates of the model are estimated using the multi‐point identification method and data points collected in the initial period of the trial. Using the parameter estimates and the numerical solutions of the model, the predictions of the reachability analysis are shown to be consistent with the clinical diagnosis at the conclusion of the trial. The methodology captures the dynamical characteristics of eventual successful, failed and marginal outcomes. The findings evidence that the reachability analysis is an appropriate tool to monitor and develop personalised antiretroviral treatment.
Investigation into the effect of shock acceleration characteristics on the performance of a proposed MEMS inertial switch
Authors: Cao Yun , Xi Zhanwen , Wang Jiong , Nie Weirong , Yu Pingxin
Published: August 2016

Rapid response is required for many applications of a micro‐electro‐mechanical system (MEMS) inertial switch device. To achieve a rapid response and have a long contact time, the influence of applied acceleration characteristics on the performance of a proposed MEMS inertial switch, such as response time and contact time, was investigated. The results indicate that the response time of the switch gradually decreases, but the contact time rapidly increases first and then smoothly increases, as the acceleration amplitude increases and the pulse width is a constant. Furthermore, the broadening of acceleration pulse width will result in a sudden increase of response time. For the sake of rapid response, the switch should be used within a limited pulse width range of 0 < t0 < 5.78π/ωn1, as the applied acceleration amplitude is 1.2 times of the acceleration threshold. The fabricated switches were tested by a shock test device. The test results are in good agreement with the simulation results.
Solitonic supercontinuum of femtosecond mid-IR pulses in W-type index tellurite fibers with two zero dispersion wavelengths
Authors: Kedenburg S. , Steinle T. , Mörz F. , Steinmann A. , Nguyen D. , Rhonehouse D. , Zong J. , Chavez-Pirson A. , Giessen H.
Published: August 2016

We present a detailed experimental parameter study on mid-IR supercontinuum generation in W-type index tellurite fibers, which reveals how the core diameter, pump wavelength, fiber length, and pump power dramatically influence the spectral broadening. As pump source, we use femtosecond mid-IR pulses from a post-amplified optical parametric oscillator tunable between 1.7 μm and 4.1 μm at 43 MHz repetition rate. We are able to generate red-shifted dispersive waves up to a wavelength of 5.1 μm by pumping a tellurite fiber in the anomalous dispersion regime between its two zero dispersion wavelengths. Distinctive soliton dynamics can be identified as the main broadening mechanism resulting in a maximum spectral width of over 2000 nm with output powers of up to 160 mW. We experimentally demonstrated that efficient spectral broadening with considerably improved power proportion in the important first atmospheric transmission window between 3 and 5 μm can be achieved in robust W-type tellurite fibers pumped at long wavelengths by ultra-fast lasers.
In-vessel calibration of the imaging diagnostics for the real-time protection of the JET ITER-like wall
Authors: Huber V. , Huber A. , Kinna D. , Balboa I. , Collins S. , Conway N. , Drewelow P. , Maggi C. F. , Matthews G. F. , Meigs A. G. , Mertens Ph. , Price M. , Sergienko G. , Silburn S. , Wynn A. , Zastrow K.-D.
Published: August 2016

The in situ absolute calibration of the JET real-time protection imaging system has been performed for the first time by means of radiometric light source placed inside the JET vessel and operated by remote handling. High accuracy of the calibration is confirmed by cross-validation of the near infrared (NIR) cameras against each other, with thermal IR cameras, and with the beryllium evaporator, which lead to successful protection of the JET first wall during the last campaign. The operation temperature ranges of NIR protection cameras for the materials used on JET are Be 650-1600 °C, W coating 600-1320 °C, and W 650-1500 °C.
Interlayer exchange coupling between layers with perpendicular and easy-plane magnetic anisotropies
Authors: Fallarino Lorenzo , Sluka Volker , Kardasz Bartek , Pinarbasi Mustafa , Berger Andreas , Kent Andrew D.
Published: August 2016

Interlayer exchange coupling between layers with perpendicular and easy-plane magnetic anisotropies separated by a non-magnetic spacer is studied using ferromagnetic resonance. The samples consist of a Co/Ni multilayer with perpendicular magnetic anisotropy and a CoFeB layer with easy-plane anisotropy separated by a variable thickness Ru layer. At a fixed frequency, we show that there is an avoided crossing of layer ferromagnetic resonance modes providing direct evidence for interlayer coupling. The mode dispersions for different Ru thicknesses are fit to a Heisenberg-type model to determine the interlayer exchange coupling strength and layer properties. The resulting interlayer exchange coupling varies continuously from antiferromagnetic to ferromagnetic as a function of the Ru interlayer thickness. These results show that the magnetic layer single domain ground state consists of magnetizations that can be significantly canted with respect to the layer planes and the canting can be tuned by varying the Ru thickness and the layer magnetic characteristics, a capability of interest for applications in spin-transfer torque devices.
Spin and charge thermopower effects in the ferromagnetic graphene junction
Authors: Vahedi Javad , Barimani Fattaneh
Published: August 2016

Using wave function matching approach and employing the Landauer-Buttiker formula, a ferromagnetic graphene junction with temperature gradient across the system is studied. We calculate the thermally induced charge and spin current as well as the thermoelectric voltage (Seebeck effect) in the linear and nonlinear regimes. Our calculation revealed that due to the electron-hole symmetry, the charge Seebeck coefficient is, for an undoped magnetic graphene, an odd function of chemical potential while the spin Seebeck coefficient is an even function regardless of the temperature gradient and junction length. We have also found with an accurate tuning external parameter, namely, the exchange filed and gate voltage, the temperature gradient across the junction drives a pure spin current without accompanying the charge current. Another important characteristic of thermoelectric transport, thermally induced current in the nonlinear regime, is examined. It would be our main finding that with increasing thermal gradient applied to the junction the spin and charge thermovoltages decrease and even become zero for non zero temperature bias.
Well-posedness for compressible MHD systems with highly oscillating initial data
Authors: Jia Junxiong , Peng Jigen , Gao Jinghuai
Published: August 2016

In this paper, a unique local solution for compressible magnetohydrodynamics systems has been constructed in the critical Besov space framework by converting the system in Euler coordinates to a system in Lagrange coordinates. Our results improve the range of the Lebesgue exponent in the Besov space from [2, N) to [2, 2N), where N denotes the space dimension. Then, we give a lower bound for the maximal existence time, which is important for our construction of global solutions. Based on the lower bound, we use the effective viscous flux and Hoff’s energy method to obtain the unique global solution, which allows the initial velocity field and the magnetic field to have large energies and allows the initial density to exhibit large oscillations on a set of small measure.
The effect of the MgO buffer layer thickness on magnetic anisotropy in MgO/Fe/Cr/MgO buffer/MgO(001)
Authors: Kozioł-Rachwał Anna , Nozaki Takayuki , Zayets Vadym , Kubota Hitoshi , Fukushima Akio , Yuasa Shinji , Suzuki Yoshishige
Published: August 2016

The relationship between the magnetic properties and MgO buffer layer thickness d was studied in epitaxial MgO/Fe(t)/Cr/MgO(d) layers grown on MgO(001) substrate in which the Fe thickness t ranged from 0.4 nm to 1.1 nm. For 0.4 nm ≤ t ≤ 0.7 nm, a non-monotonic coercivity dependence on the MgO buffer thickness was shown by perpendicular magneto-optic Kerr effect magnetometry. For thicker Fe films, an increase in the buffer layer thickness resulted in a spin reorientation transition from perpendicular to the in-plane magnetization direction. Possible origins of these unusual behaviors were discussed in terms of the suppression of carbon contamination at the Fe surface and changes in the magnetoelastic anisotropy in the system. These results illustrate a method to control magnetic anisotropy in MgO/Fe/Cr/MgO(d) via an appropriate choice of MgO buffer layer thickness d.
Absolute continuum intensity diagnostics of a novel large coaxial gridded hollow cathode argon plasma
Authors: Gao Ruilin , Yuan Chengxun , Li Hui , Jia Jieshu , Zhou Zhong-Xiang , Wu Jian , Wang Ying , Wang Xiaoou
Published: August 2016

This paper reports a novel coaxial gridded hollow discharge during operation at low pressure (20 Pa–80 Pa) in an argon atmosphere. A homogeneous hollow discharge was observed under different conditions, and the excitation mechanism and the discharge parameters for the hollow cathode plasma were examined at length. An optical emission spectrometry (OES) method, with a special focus on absolute continuum intensity method, was employed to measure the plasma parameters. The Langmuir probe measurement (LPM) was used to verify the OES results. Both provided electron density values (ne) in the order of 1016 m−3 for different plasma settings. Taken together, the results show that the OES method is an effective approach to diagnosing the similar plasma, especially when the LPM is hardly operated.
Structure and energetics of nanotwins in cubic boron nitrides
Authors: Zheng Shijian , Zhang Ruifeng , Huang Rong , Taniguchi Takashi , Ma Xiuliang , Ikuhara Yuichi , Beyerlein Irene J.
Published: August 2016

Recently, nanotwinned cubic boron nitrides (NT c-BN) have demonstrated extraordinary leaps in hardness. However, an understanding of the underlying mechanisms that enable nanotwins to give orders of magnitude increases in material hardness is still lacking. Here, using transmission electron microscopy, we report that the defect density of twin boundaries depends on nanotwin thickness, becoming defect-free, and hence more stable, as it decreases below 5 nm. Using ab initio density functional theory calculations, we reveal that the Shockley partials, which may dominate plastic deformation in c-BNs, show a high energetic barrier. We also report that the c-BN twin boundary has an asymmetrically charged electronic structure that would resist migration of the twin boundary under stress. These results provide important insight into possible nanotwin hardening mechanisms in c-BN, as well as how to design these nanostructured materials to reach their full potential in hardness and strength.
Optical configuration optimization and calibration for the POINT system on EAST
Authors: Zou Z. Y. , Liu H. Q. , Li W. M. , Lian H. , Wang S. X. , Yao Y. , Lan T. , Zeng L. , Jie Y. X.
Published: August 2016

Calibration of the polarimeter system is one of the key elements to determine the overall measurement accuracy. The anisotropic reflection and transmission properties of the mesh beam splitters can easily distort the polarization state of the circularly polarized beams. Using a rotating crystal quartz λ/2-waveplate to replace the plasma can effectively allow us to obtain the ratio of the measured Faraday rotation angle to the known rotation angle of the waveplate. This ratio is used to estimate the calibration factor for each chord to be accurately determined and help to minimize distortions introduced by the wire-mesh beam splitters. With the novel configuration optimization, the distortion of polarization state is effectively eliminated.
Calibration of a two-color soft x-ray diagnostic for electron temperature measurement
Authors: Reusch L. M. , Den Hartog D. J. , Franz P. , Goetz J. , McGarry M. B. , Stephens H. D.
Published: August 2016

The two-color soft x-ray (SXR) tomography diagnostic on the Madison Symmetric Torus is capable of making electron temperature measurements via the double-filter technique; however, there has been a 15% systematic discrepancy between the SXR double-filter (SXRDF) temperature and Thomson scattering (TS) temperature. Here we discuss calibration of the Be filters used in the SXRDF measurement using empirical measurements of the transmission function versus energy at the BESSY II electron storage ring, electron microprobe analysis of filter contaminants, and measurement of the effective density. The calibration does not account for the TS and SXRDF discrepancy, and evidence from experiments indicates that this discrepancy is due to physics missing from the SXRDF analysis rather than instrumentation effects.
Plasma rotation in the Peking University Plasma Test device
Authors: Xiao Chijie , Chen Yihang , Yang Xiaoyi , Xu Tianchao , Wang Long , Xu Min , Guo Dong , Yu Yi , Lin Chen
Published: August 2016

Some preliminary results of plasma rotations in a linear plasma experiment device, Peking University Plasma Test (PPT) device, are reported in this paper. PPT has a cylindrical vacuum chamber with 500 mm diameter and 1000 mm length, and a pair of Helmholtz coils which can generate cylindrical or cusp magnetic geometry with magnitude from 0 to 2000 G. Plasma was generated by a helicon source and the typical density is about 1013 cm−3 for the argon plasma. Some Langmuir probes, magnetic probes, and one high-speed camera are set up to diagnose the rotational plasmas. The preliminary results show that magnetic fluctuations exist during some plasma rotation processes with both cylindrical and cusp magnetic geometries, which might be related to some electromagnetic processes and need further studies.
Structured photocathodes for improved high-energy x-ray efficiency in streak cameras
Authors: Opachich Y. P. , Bell P. M. , Bradley D. K. , Chen N. , Feng J. , Gopal A. , Hatch B. , Hilsabeck T. J. , Huffman E. , Koch J. A. , Landen O. L. , MacPhee A. G. , Nagel S. R. , Udin S.
Published: August 2016

We have designed and fabricated a structured streak camera photocathode to provide enhanced efficiency for high energy X-rays (1–12 keV). This gold coated photocathode was tested in a streak camera and compared side by side against a conventional flat thin film photocathode. Results show that the measured electron yield enhancement at energies ranging from 1 to 10 keV scales well with predictions, and that the total enhancement can be more than 3×. The spatial resolution of the streak camera does not show degradation in the structured region. We predict that the temporal resolution of the detector will also not be affected as it is currently dominated by the slit width. This demonstration with Au motivates exploration of comparable enhancements with CsI and may revolutionize X-ray streak camera photocathode design.
Rational design of mass diffusion metamaterial concentrators based on coordinate transformations
Authors: Restrepo-Flórez Juan Manuel , Maldovan Martin
Published: August 2016

Recent advances in coordinate transformations of Fick's equation have paved the way for the design of metamaterial devices that can manipulate mass diffusion flux. The control of diffusion paths has a great potential for the design of novel catalytic and separation systems in chemical and biomolecular engineering. In order to explore these new applications, it is necessary to understand mass diffusion in coordinate transformation metamaterial devices. In this work, we present a comprehensive study on the impact of structure and material properties on the resultant physical properties of mass concentrator metamaterial shells. The concentration gradient at the core, the total mass flow rate towards the core, and the disturbance of the external concentration field are systematically examined in order to provide guidelines for the rational design and fabrication of metamaterial mass concentrators. A practical case is also presented where the concentration of oxygen diffusing in a polymeric system is studied.