bluuebunny/crossref_metadata_2025 huggingface dataset:
Sonic horizon formation for oscillating Bose-Einstein condensates in isotropic harmonic potential
Authors: Wang Ying , Zhou Yu , Zhou Shuyu
Published: December 2016

We study the sonic horizon phenomena of the oscillating Bose-Einstein condensates in isotropic harmonic potential. Based on the Gross-Pitaevskii equation model and variational method, we derive the original analytical formula for the criteria and lifetime of the formation of the sonic horizon, demonstrating pictorially the interaction parameter dependence for the occur- rence of the sonic horizon and damping effect of the system distribution width. Our analytical results corroborate quantitatively the particular features of the sonic horizon reported in previous numerical study.
Arctic megaslide at presumed rest
Authors: Geissler Wolfram H. , Gebhardt A. Catalina , Gross Felix , Wollenburg Jutta , Jensen Laura , Schmidt-Aursch Mechita C. , Krastel Sebastian , Elger Judith , Osti Giacomo
Published: December 2016

Slope failure like in the Hinlopen/Yermak Megaslide is one of the major geohazards in a changing Arctic environment. We analysed hydroacoustic and 2D high-resolution seismic data from the apparently intact continental slope immediately north of the Hinlopen/Yermak Megaslide for signs of past and future instabilities. Our new bathymetry and seismic data show clear evidence for incipient slope instability. Minor slide deposits and an internally-deformed sedimentary layer near the base of the gas hydrate stability zone imply an incomplete failure event, most probably about 30000 years ago, contemporaneous to or shortly after the Hinlopen/Yermak Megaslide. An active gas reservoir at the base of the gas hydrate stability zone demonstrate that over-pressured fluids might have played a key role in the initiation of slope failure at the studied slope, but more importantly also for the giant HYM slope failure. To date, it is not clear, if the studied slope is fully preconditioned to fail completely in future or if it might be slowly deforming and creeping at present. We detected widespread methane seepage on the adjacent shallow shelf areas not sealed by gas hydrates.
Sex Differences in Prevalence of and Risk Factors for Carotid Plaque among Adults: A Population-based Cross-Sectional Study in Rural China
Authors: Zhao Wei , Wu Yanan , Shi Min , Bai Lingling , Tu Jun , Guo Zaiyu , Jiang Rongcai , Zhang Jianning , Ning Xianjia , Wang Jinghua
Published: December 2016

Although the associations between carotid plaque and cardiovascular disease risk factors have been identified in previous studies, there is limited information on sex-related differences in factors associated with the development of carotid plaque. We aimed to determine sex differences in the prevalence of carotid plaque and associated risk factors in rural China. A total of 3,789 subjects aged ≥45 years without history of stroke or cardiovascular disease were recruited to the study. B-mode ultrasonography was performed to determine the presence of carotid plaque. The mean age of male subjects was greater than that of female subjects. In addition, there was a higher prevalence of carotid plaque in men than in women (50.1% vs. 35.5%; P < 0.001) irrespective of age group, education level, and presence of risk factors. Older age, hypertension, diabetes mellitus, and high concentrations of low-density lipoprotein cholesterol were pronouncedly associated with the risk of carotid plaque in both men and women. These findings suggest that it is vital for physicians to be aware that conventional risk factors and other related factors are of equal importance among rural residents in China; patients should thus be treated accordingly so that reduce the burden of stroke and cardiovascular disease.
Social determinants of eyeblinks in adult male macaques
Authors: Ballesta Sébastien , Mosher Clayton P. , Szep Jeno , Fischl Kate D. , Gothard Katalin M.
Published: December 2016

Videos with rich social and emotional content elicit natural social behaviors in primates. Indeed, while watching videos of conspecifics, monkeys engage in eye contact, gaze follow, and reciprocate facial expressions. We hypothesized that the frequency and timing of eyeblinks also depends on the social signals contained in videos. We monitored the eyeblinks of four male adult macaques while they watched videos of conspecifics displaying facial expressions with direct or averted gaze. The instantaneous blink rate of all four animals decreased during videos. The temporal synchrony of blinking, however, increased in response to segments depicting appeasing or aggressive facial expressions directed at the viewer. Two of the four monkeys, who systematically reciprocated the direct gaze of the stimulus monkeys, also showed eyeblink entrainment, a temporal coordination of blinking between social partners engaged in dyadic interactions. Together, our results suggest that in macaques, as in humans, blinking depends not only on the physiological imperative to protect the eyes and spread a film of tears over the cornea, but also on several socio-emotional factors.
Mesolimbic leptin signaling negatively regulates cocaine-conditioned reward
Authors: Shen M , Jiang C , Liu P , Wang F , Ma L
Published: December 2016

The regulatory mechanisms underlying the response to addictive drugs are complex, and increasing evidence indicates that there is a role for appetite-regulating pathways in substance abuse. Leptin, an important adipose hormone that regulates energy balance and appetite, exerts its physiological functions via leptin receptors. However, the role of leptin signaling in regulating the response to cocaine remains unclear. Here we examined the potential role of leptin signaling in cocaine reward using a conditioned place preference (CPP) procedure. Our results showed that inhibition of leptin signaling by intracerebroventricular infusion of the leptin receptor (LepR) antagonist SMLA during cocaine conditioning increased the cocaine-CPP and upregulated the level of dopamine and its metabolites in the nucleus accumbens (NAc). We then selectively knocked down the LepR in the mesolimbic ventral tegmental area (VTA), NAc core and central amygdala (CeA) by injecting AAV-Cre into Leprflox/flox mice. LepR deletion in the VTA increased the dopamine levels in the NAc and enhanced the cocaine-conditioned reward. LepR deletion in the NAc core enhanced the cocaine-conditioned reward and impaired the effect of the D2-dopamine receptor on cocaine-CPP, whereas LepR deletion in the CeA had no effect on cocaine-CPP but increased the anxiety level of mice. In addition, prior exposure to saccharin increased LepR mRNA and STAT3 phosphorylation in the NAc and VTA and impaired cocaine-CPP. These results indicate that leptin signaling is critically involved in cocaine-conditioned reward and the regulation of drug reward by a natural reward and that these effects are dependent on mesolimbic LepR.
Brain network reorganization differs in response to stress in rats genetically predisposed to depression and stress-resilient rats
Authors: Gass N , Becker R , Schwarz A J , Weber-Fahr W , Clemm von Hohenberg C , Vollmayr B , Sartorius A
Published: December 2016

Treatment-resistant depression (TRD) remains a pressing clinical problem. Optimizing treatment requires better definition of the specificity of the involved brain circuits. The rat strain bred for negative cognitive state (NC) represents a genetic animal model of TRD with high face, construct and predictive validity. Vice versa, the positive cognitive state (PC) strain represents a stress-resilient phenotype. Although NC rats show depressive-like behavior, some symptoms such as anhedonia require an external trigger, i.e. a stressful event, which is similar to humans when stressful event induces a depressive episode in genetically predisposed individuals (gene–environment interaction). We aimed to distinguish neurobiological predisposition from the depressogenic pathology at the level of brain-network reorganization. For this purpose, resting-state functional magnetic resonance imaging time series were acquired at 9.4 Tesla scanner in NC (N=11) and PC (N=7) rats before and after stressful event. We used a graph theory analytical approach to calculate the brain-network global and local properties. There was no difference in the global characteristics between the strains. At the local level, the response in the risk strain was characterized with an increased internodal role and reduced local clustering and efficiency of the anterior cingulate cortex (ACC) and prelimbic cortex compared to the stress-resilient strain. We suggest that the increased internodal role of these prefrontal regions could be due to the enhancement of some of their long-range connections, given their connectivity with the amygdala and other default-mode-like network hubs, which could create a bias to attend to negative information characteristic for depression.
GC columns as micro-air samplers for the quantitative analysis of naphthalene vapours
Authors: Gura Sigalit , Madmon Moran , Tzanani Nitzan , Barak Ruth , Shacht Israel , Dagan Shai
Published: December 2016

Although linked to a number of adverse health effects, studies of naphthalene are lacking in the exposure-relevant literature.
Thermoresponsive microgels containing trehalose as soft matrices for 3D cell culture
Authors: Burek Małgorzata , Waśkiewicz Sylwia , Lalik Anna , Student Sebastian , Bieg Tadeusz , Wandzik Ilona
Published: December 2016

PNIPAM-based glycomicrogels containing trehalose were synthesized, characterized and examined as matrices for 3D cell culture.
A direct cross-coupling reaction of electron-deficient alkenes using an oxidizing directing group
Authors: Yu Chunbing , Li Feifei , Zhang Jian , Zhong Guofu
Published: December 2016

An oxidant-free cross-coupling of electron-deficient alkenes using an inexpensive ruthenium catalyst is reported, efficiently providing valuable 1,3-butadienes with excellentZ,Eselectivities.
Hyperbranched polymer as an acceptor for polymer solar cells
Authors: Zhang Jicheng , Xie Sufei , Zhang Xuejuan , Lu Zhen , Xiao Hongmei , Li Cuihong , Li Guangwu , Xu Xinjun , Chen Xuebo , Bo Zhishan
Published: December 2016

For the first time, a hyperbranched polymer acceptor, HP-PDI, was designed, synthesized and applied in polymer solar cells (PSCs).
A microchip electrophoresis-based fluorescence signal amplification strategy for highly sensitive detection of biomolecules
Authors: Qin Yingfeng , Zhang Liangliang , Li Shuting , Zhao Jingjin , Huang Yong , Zhao Shulin , Liu Yi-Ming
Published: December 2016

A microchip electrophoresis-based fluorescence signal amplification strategy was developed for highly sensitive detection of biomolecules.
Replica exchange molecular dynamics study of the truncated amyloid beta (11–40) trimer in solution
Authors: Ngo Son Tung , Hung Huynh Minh , Truong Duc Toan , Nguyen Minh Tho
Published: December 2016

The structure of the 3Aβ11–40oligomer is determined for the first time using T-REMD simulations.
Quantum and classical inter-cage hopping of hydrogen molecules in clathrate hydrate: temperature and cage-occupation effects
Authors: Burnham Christian J. , Futera Zdenek , English Niall J.
Published: December 2016

The free-energy barriers for hydrogen hopping between clathrate-hydrate cavities were evaluated at 50–200 K. Nuclear quantum effects are significant.
Surface chemistry and density distribution influence on visible luminescence of silicon quantum dots: an experimental and theoretical approach
Authors: Dutt Ateet , Matsumoto Yasuhiro , Santana-Rodríguez G. , Ramos Estrella , Monroy B. Marel , Santoyo Salazar J.
Published: December 2016

Visible luminescence and hence the mechanism of emission from Si QDs depending on the size and/or the passivation environment are presented.
Chewing bread: impact on alpha-amylase secretion and oral digestion
Authors: Joubert Marianne , Septier Chantal , Brignot Hélène , Salles Christian , Panouillé Maud , Feron Gilles , Tournier Carole
Published: December 2016

During chewing, saliva helps in preparing the food bolus by agglomerating the formed particles, and it initiates enzymatic food breakdown.
Nitrate reduction on the surface of bimetallic catalysts supported by nano-crystalline beta-zeolite (NBeta)
Authors: Hamid Shanawar , Kumar Macharla Arun , Han Jong-In , Kim Hyungjun , Lee Woojin
Published: December 2016

A nano-crystalline beta zeolite supported bimetallic catalyst was developed and evaluated for the complete and selective reduction of nitrate to environmentally friendly nitrogen.
Investigation of 1,2,3-trialkylimidazolium ionic liquids: experiment and density functional theory calculations
Authors: Papović Snežana , Vraneš Milan , Armaković Stevan , Armaković Sanja J. , Szécsényi Katalin Mészáros , Bešter-Rogač Marija , Gadžurić Slobodan
Published: December 2016

Physico-chemical properties, thermal stability and bonding in 1,2,3-trialkylimidazolium based ionic liquids (ILs) were investigated by viscosity and density measurements together with thermogravimetric analysis (TGA) and IR spectroscopy.
Stereoselective preparation of conjugated (Z)-1,3-enynes by dehydration reactions of allenic bromohydrins and the use of the enynes in base-mediated tandem allylation ene-carbocyclization reactions with β-ketoesters
Authors: Lin Mei-Huey , Chen Yu-Chun , Chiu Shih-Hao , Liang Kung-Yu , Lee Yi-Lin , Chuang Tsung-Hsun
Published: December 2016

Highly substituted cyclopentadienes are synthesized from allenic bromohydrins through Sc(OTf)3 catalyzed dehydration, allylation, ene-carbocyclization, and 1,5-acyl migration.
The biological in vitro effect and selectivity shown by a CoIIcomplex of 2-(2-hydroxyphenylazo)-indole-3′-acetic acid on three distinctly different cancer cells
Authors: Ganguly Durba , Jain Chetan Kumar , Chandra Santra Ramesh , Roychoudhury Susanta , Majumder Hemanta Kumar , Das Saurabh
Published: December 2016

Reductive cleavage of azo bond in a CoIIcomplex of HPIA decreased significantly implying less toxicity. On human colon carcinoma HCT116, ALL MOLT-4 & MCF-7 breast cancer cells complex was more effective than HPIA but less toxic towards normal cells.
Highly sensitive and selective fluorescence detection of Hg(ii) ions based on R-phycoerythrin from Porphyra yezoensis
Authors: Wang Quanfu , Xu Yifeng , Hou Yanhua , Wang Yifan , Yan Meihong , Zhang Xiangyu , Wang Hua
Published: December 2016

R-Phycoerythrin (R-PE) is a kind of natural fluorescent protein from marine Porphyra yezoensis.
Study on the synthesis of MFI and FER in the presence of n-butylamine and the property of n-butylamine in a confined region of zeolites
Authors: Zhang Shaoqing , Liu Xin , Zhang Yifu , Lv Tianming , Zheng Jiqi , Gao Wenyan , Liu Xiaoyu , Cui Miao , Meng Changgong
Published: December 2016

N-Butylamine restricted in MFI and FER was oxidized by hydrogen peroxide.
The preparation of sub-micron spherical Fe-Ph/Cl-20 by the spray-drying method and its combustion
Authors: Song Nai-Meng , Gan Rui-Yi , Zhao Wen-Yuan , Zhang Guo-Ying , Yang Li
Published: December 2016

This study introduces the preparation of sub-micron composite particles of phloroglucinol-Fe and Cl-20 (Fe-Ph/Cl-20) with a spherical shape using spray drying technology.
Synthetic lipopeptides as potential topical therapeutics in wound and skin care: in vitro studies of permeation and skin cells behaviour
Authors: Kukowska Monika , Pikuła Michał , Kukowska-Kaszuba Magdalena , Schumacher Adriana , Dzierzbicka Krystyna , Trzonkowski Piotr
Published: December 2016

Wound healing is an extraordinarily complicated process associating with the cell aging, slowing down of cell renewal mechanism and even loss of protective function to environmentally induced oxidative stress.
Silver-decorated reduced graphene oxides as novel building blocks for transparent conductive films
Authors: He Linxiang , Tjong Sie Chin
Published: December 2016

Silver-decorated reduced graphene oxides as the building blocks for transparent conducting electrodes.
Why conclusions from platinum model surfaces do not necessarily lead to enhanced nanoparticle catalysts for the oxygen reduction reaction
Authors: Calle-Vallejo Federico , Pohl Marcus D. , Reinisch David , Loffreda David , Sautet Philippe , Bandarenka Aliaksandr S.
Published: December 2016

Platinum model-surface and nanoparticle catalysts for the oxygen reduction reaction are enhanced by the presence of concave sites.
Hierarchical porous carbon with ordered straight micro-channels templated by continuous filament glass fiber arrays for high performance supercapacitors
Authors: Jia Dedong , Yu Xin , Tan Hua , Li Xuequan , Han Feng , Li Linlin , Liu Hong
Published: December 2016

Hierarchical porous carbon with highly ordered straight micro-channels was prepared though a facile melt vacuum infiltration method using continuous filament glass fiber arrays as the template and glucose as the precursor.
Large-area high-efficiency perovskite solar cells based on perovskite films dried by the multi-flow air knife method in air
Authors: Gao Li-Li , Li Cheng-Xin , Li Chang-Jiu , Yang Guan-Jun
Published: December 2016

Multi-flow air knife (MAK): a novel method for large area perovskite film production.
A long-life rechargeable Al ion battery based on molten salts
Authors: Song Yang , Jiao Shuqiang , Tu Jiguo , Wang Junxiang , Liu Yingjun , Jiao Handong , Mao Xuhui , Guo Zhancheng , Fray Derek J.
Published: December 2016

In this study, we established a rechargeable aluminum ion super battery with high-rate capability using a low temperature inorganic molten salt which is much cheaper, safer and environmentally friendly.
Low-temperature growth of polyethylene glycol-doped BiZn2VO6 nanocompounds with enhanced photoelectrochemical properties
Authors: Elhag S. , Tordera D. , Deydier T. , Lu J. , Liu X. , Khranovskyy V. , Hultman L. , Willander M. , Jonsson M. P. , Nur O.
Published: December 2016

We demonstrate scalable, low-cost and low-temperature (<100 °C) chemical growth of bismuth–zinc vanadate (BiZn2VO6) nanocompounds by BiVO4 growth on ZnO nanobelts (NBs).
Rational design of dendritic thermoresponsive nanogels that undergo phase transition under endolysosomal conditions
Authors: Rimondino G. N. , Miceli E. , Molina M. , Wedepohl S. , Thierbach S. , Rühl E. , Strumia M. , Martinelli M. , Calderón M.
Published: December 2016

Conditions inside lysosome trigger nanogel transition and Cis-Pt release into tumor cells.
An ultra-light antibacterial bagasse–AgNP aerogel
Authors: Shen Zuguang , Han Guocheng , Wang Xiaoying , Luo Jiwen , Sun Runcang
Published: December 2016

An antibacterial biomass-based ultra-light aerogel with AgNPs was fabricated, where AgNPs were synthesized with bagasse as a reducing and stabilizing agent.
An intracellular temperature nanoprobe based on biosynthesized fluorescent copper nanoclusters
Authors: Ye Jing , Dong Xiawei , Jiang Hui , Wang Xuemei
Published: December 2016

We have established a facile, efficient and green strategy for the preparation of an intracellular temperature nanoprobe specifically by in situ biosynthesized fluorescent CuNCs.
Crystallization and conformation engineering of solution-processed polymer transparent electrodes with high conductivity
Authors: Hu Aifeng , Tan Licheng , Hu Xiaotian , Hu Lin , Ai Qingyun , Meng Xiangchuan , Chen Lie , Chen Yiwang
Published: December 2016

An S-PEDOT:PSS:PEG4000 transparent electrode was fabricated via weakening the ionic interactions in PEDOT:PSS with PEG4000 and its further conformational transformation by H2SO4.
A meta-analysis of the association of serum ischaemia-modified albumin levels with human hypothyroidism and hyperthyroidism
Authors: Reddy Varikasuvu Seshadri , Bukke Suman , Mahato Khageshwar , Kumar Vinod , Reddy Netala Vasudeva , Munikumar Manne , Vodelu Bramahanapally
Published: December 2016

Serum levels of ischaemia-modified albumin (IMA) have been studied as a novel and simple measure of oxidative stress (OXS) in different thyroid pathologies. However, results of available studies in the literature were not consistent. This meta-analysis was attempted to quantify the overall effect size for serum IMA levels in human hypothyroidism (HT) and hyperthyroidism (HYT) and to study its associations with the thyroid profile. Databases of PubMed/Medline, EMBASE, Google Scholar, Web of Science and Science Direct were searched for articles. Data on serum IMA levels in HT, HYT patients and euthyroid controls were extracted to compute standardized mean differences (SMD) by the random-effects model. The associations between IMA and thyroid profile were computed by the meta-analysis of correlation coefficients. IMA levels in HT patients (SMD=1.12; Z=2.76; P=0.006) and HYT patients (SMD=1.64; Z=2.57; P=0.01) were significantly higher than in euthyroid controls and the thyroid treatment showed a favourble effect on serum IMA levels. There were strong and significant correlations between IMA and hormonal status in HT and HYT groups. This meta-analysis showing increased IMA level in both HT and HYT patients and its association with thyroid profile suggests that serum IMA could be used as a simple measure of increased OXS in thyroid dysfunction.
Hypermethylation of brain natriuretic peptide gene is associated with the risk of rheumatic heart disease
Authors: Li Ni , Zheng Dawei , Sun Lebo , Shi Huoshun , Zhu Xiuying , Xu Guodong , Wang Qinning , Zhu Caimin , Shao Guofeng
Published: December 2016

To investigate the contribution of brain natriuretic peptide (BNP) promoter DNA methylation to the risk of rheumatic heart disease (RHD) and the influence of warfarin anticoagulant therapy on BNP methylation levels for RHD patients after surgery. BNP methylation levels were determined by bisulfite pyrosequencing from plasma samples of RHD patients compared with healthy controls. Several factors influencing the RHD patients were included like age, smoking and cholesterol levels. A fragment of five CG sites (CpG1–5) in the promoter region of BNP gene was measured. BNP gene hypermethylation was found in CpG4 and CpG5 in RHD patients compared with non-RHD controls. A significant difference was also observed between RHD patients with long-term administration of warfarin and RHD patients who had recently undergone an operation. Moreover, single CpG4 and CpG5 analysis revealed a significant increase in methylation levels in men. BNP gene body hypermethylation is associated with the risk of RHD, and also influenced by the warfarin anticoagulant therapy of RHD patients after surgery, which could represent novel and promising targets for therapeutic development.
Maximising the minimum achievable secrecy rate of two‐way relay networks using the null space beamforming method
Authors: Khordad Erfan , Akhlaghi Soroush , Mirzaee Meysam
Published: December 2016

This study concerns maximising the minimum achievable secrecy rate (ASR) of a two‐way relay network in the presence of an eavesdropper, in which two nodes aim to exchange messages in two hops, using a multi‐antenna relay. Throughout the first hop, the two nodes simultaneously transmit their messages to the relay. In the second hop, the relay broadcasts a combination of the received information to the users such that the transmitted signal lies in the null space of the eavesdropper's channel; this is called null space beamforming (NSBF). The best NSBF matrix for maximising the minimum ASR is studied, showing that the problem is not convex in general. To address this issue, the problem is divided into three sub‐problems: a close‐to‐optimal solution is derived by using the semi‐definite relaxation technique. Simulation results demonstrate the superiority of the proposed method w.r.t. the most well‐known method addressed in the literature.
Design of dual‐mode decoder based on LDPC/turbo code
Authors: Wang Xiumin , Li Jun , Wang Yi , Yin Haibing , Li Tingting , Cao Weilin
Published: December 2016

In this study, the authors propose the dual‐mode low‐density parity‐check (LDPC)/turbo decoder which operates by sharing the computing and the storage units. The decoder supports both Wimax and TD‐LTE standards, and can make up for the inadequacy of the design of storage units in current researches. First, in terms of storage units sharing, this study uses the look‐up table which uses a third less resource than the existing literature. Second, a storage mode is proposed using splicing storage units, which has the maximum occupancy rate of storage units of 47 and 98% in the LDPC and turbo mode, respectively. Furthermore there are only 5 and 2% differences when compared with the theoretical occupancy rates. Compared with the turbo/LDPC decoder made by Carlo, the design of the storage units in this study is more efficient. The storage consumption of each bit is 34 bits, saving about 13% storage units under the same conditions. As to realise the same functions in the LDPC decoder and turbo decoder, the consumption of the logic elements is 33% less than that in existing literature.
From a latent to a ‘strong’ soft power? The evolution of India’s cultural diplomacy
Authors: Mahapatra Debidatta Aurobinda
Published: December 2016

India celebrated when in 2014 the United Nations adopted the 21st of June as International Yoga Day. In recent years India’s leaders have increasingly focused on its diaspora, multicultural ethos, and its ancient practices like yoga, through official campaigns and foreign visits. Particularly since Narendra Modi came to power in 2014, there has been an increased activism to draw attention to and employ India’s soft power. The article traces the evolution of India as a soft power since its emergence as an independent country. It explores how this soft power has shaped India’s foreign policy and behavior. India’s soft power assets are not of recent origin, but there is an increasing activism to use those assets effectively. Has India evolved as a soft power? What are the characteristics of India’s soft power? How is India’s current political dispensation different from the earlier ones in applying soft power in foreign policy? The article addresses these questions by applying Nye Jr’s concept of soft power and aims to contribute to the debate on soft power by focusing on cultural diplomacy of a rising power. It demonstrates that though soft power resources, including culture, are not new, the increasing awareness and activism of India’s political class to use those resources to realize foreign policy goals is recent. The focus on soft power, particularly cultural diplomacy, and its use in foreign policy, has become increasingly visible in recent years. This article also argues that the increasing acceptability of its culture and values opens up possibilities for India to realize foreign policy goals. It will, however, be a daunting task for members of the Indian political class to use soft power effectively unless they address internal and external constraints. This article is published as part of a collection on soft power.
Spontaneous rotation of an ice disk while melting on a solid plate
Authors: Dorbolo S. , Vandewalle N. , Darbois Texier B.
Published: December 2016

Ice disks were released at the surface of a thermalised aluminium plate. The fusion of the ice creates a lubrication film between the ice disk and the plate. The situation is similar to the Leidenfrost effect reported for a liquid droplet evaporating at the surface of a plate which temperature is above the boiling temperature of the liquid. An analogy is depicted between the Leidenfrost phenomenon and the rapid fusion of a solid at the contact of a hot plate. Similarly to Leidenfrost droplet, we observe that, while the ice disks were melting, the disks were very mobile: translation and rotation. A hole was drilled in the plate and allowed the canalising of the melted liquid. Under these conditions, we discover that the rotation of the ice disk is systematic and persistent. Moreover, the rotation speed increases with the temperature of the plate and with the load put on the ice disk. A model is proposed to explain the spontaneous rotation of the ice disk. We claim that the rotation is due to the viscous drag of the liquid that flows around the ice disk.
Tangent map intermittency as an approximate analysis of intermittency in a high dimensional fully stochastic dynamical system: The Tangled Nature model
Authors: Diaz-Ruelas Alvaro , Jeldtoft Jensen Henrik , Piovani Duccio , Robledo Alberto
Published: December 2016

It is well known that low-dimensional nonlinear deterministic maps close to a tangent bifurcation exhibit intermittency and this circumstance has been exploited, e.g., by Procaccia and Schuster [Phys. Rev. A 28, 1210 (1983)], to develop a general theory of 1/f spectra. This suggests it is interesting to study the extent to which the behavior of a high-dimensional stochastic system can be described by such tangent maps. The Tangled Nature (TaNa) Model of evolutionary ecology is an ideal candidate for such a study, a significant model as it is capable of reproducing a broad range of the phenomenology of macroevolution and ecosystems. The TaNa model exhibits strong intermittency reminiscent of punctuated equilibrium and, like the fossil record of mass extinction, the intermittency in the model is found to be non-stationary, a feature typical of many complex systems. We derive a mean-field version for the evolution of the likelihood function controlling the reproduction of species and find a local map close to tangency. This mean-field map, by our own local approximation, is able to describe qualitatively only one episode of the intermittent dynamics of the full TaNa model. To complement this result, we construct a complete nonlinear dynamical system model consisting of successive tangent bifurcations that generates time evolution patterns resembling those of the full TaNa model in macroscopic scales. The switch from one tangent bifurcation to the next in the sequences produced in this model is stochastic in nature, based on criteria obtained from the local mean-field approximation, and capable of imitating the changing set of types of species and total population in the TaNa model. The model combines full deterministic dynamics with instantaneous parameter random jumps at stochastically drawn times. In spite of the limitations of our approach, which entails a drastic collapse of degrees of freedom, the description of a high-dimensional model system in terms of a low-dimensional one appears to be illuminating.
Modelling nonlinear electrostatic oscillations in plasmas
Authors: Diver D. A. , Laing E. W.
Published: December 2016

The nonlinear 1-D plasma electrostatic oscillation is formulated in an analytic framework that allows closed-form analytic solutions along the characteristics, and solved numerically in configuration space. Additionally, a novel iterative analytical form for the finite-amplitude oscillation solution is derived, which compares favourably with the other two techniques. A fresh insight into the evolution of the oscillation is gained, including defining the least achievable density in the nonlinear oscillation as half of the equilibrium value, and relating the associated maximum density achievable in terms of that minimum.
Dynamical density functional theory with hydrodynamic interactions in confined geometries
Authors: Goddard B. D. , Nold A. , Kalliadasis S.
Published: December 2016

We study the dynamics of colloidal fluids in both unconfined geometries and when confined by a hard wall. Under minimal assumptions, we derive a dynamical density functional theory (DDFT) which includes hydrodynamic interactions (HI; bath-mediated forces). By using an efficient numerical scheme based on pseudospectral methods for integro-differential equations, we demonstrate its excellent agreement with the full underlying Langevin equations for systems of hard disks in partial confinement. We further use the derived DDFT formalism to elucidate the crucial effects of HI in confined systems.
Correlation between AC and DC transport properties of Mn substituted cobalt ferrite
Authors: Supriya Sweety , Kumar Sunil , Kar Manoranjan
Published: December 2016

The CoFe2-xMnxO4 compound is prepared by following the sol gel technique. The structural analysis through XRD and Rietveld has been confirmed for the single cubic phase having Fd3¯m space group for CoFe2-xMnxO4 and also verified it through Raman spectroscopy measurements. The tetrahedral site observed to be red shifted with increase in Mn concentration in cobalt ferrite. All the XRD patterns have been analyzed by employing the Rietveld refinement technique. The particle size was found to be in the range of 30–40 nm. The electrical properties of polycrystalline CoFe2-xMnxO4 for x = 0.00, 0.10, 0.15, and 0.2, spinel ferrite was investigated by impedance spectroscopy. The influence of doping, frequency and temperature on the electrical transport properties of the CoFe2-xMnxO4 for x = 0.00, 0.10, 0.15, and 0.20 were investigated. The magnitude of Z′ and Z″ decreases with increase in temperature. Only one semicircle is observed in each Cole Cole plot which reveals that ac conductivity is dominated by grains. The grain resistance and grain boundary resistance both were found to decrease as a function of temperature. Temperature variation of DC electrical conductivity follows the Arrhenius relationship. A detailed analysis of electrical parameters provides assistance in connecting information regarding the conduction mechanism as well as determination of both dielectric and magnetic transition temperatures in the substituted cobalt ferrite. Detailed analysis of ac impedance and DC resistivity measurement reveals that, the magnetic ordering temperature in the Mn substituted cobalt ferrite does not respond to the frequency of ac electrical signal; however, it responds to the DC resistivity. The correlation between ac impedance and DC resistivity has been established.
Helical temperature perturbations associated with radially asymmetric magnetic island chains in tokamak plasmas
Authors: Fitzpatrick Richard
Published: December 2016

The simple analysis of Rutherford [Phys. Fluids 16, 1903 (1973)] is generalized in order to incorporate radial magnetic island asymmetry into the nonlinear theory of tearing mode stability in a low-β, large aspect-ratio, quasi-cylindrical, tokamak plasma. The calculation is restricted to cases in which the radial shifts of the island X- and O-points are (almost) equal and opposite. For the sake of simplicity, the calculation concentrates on a particular (but fairly general) class of radially asymmetric island magnetic flux-surfaces that can all be mapped to the same symmetric flux-surfaces by means of a suitable coordinate transform. The combination of island asymmetry (in which the radial shifts of the X- and O-points are almost equal and opposite) and temperature-induced changes in the inductive current profile in the immediate vicinity of the island is found to have no effect on tearing mode stability.
Characterization of the secondary flow in hexagonal ducts
Authors: Marin O. , Vinuesa R. , Obabko A. V. , Schlatter P.
Published: December 2016

In this work we report the results of DNSs and LESs of the turbulent flow through hexagonal ducts at friction Reynolds numbers based on centerplane wall shear and duct half-height Reτ,c ≃ 180, 360, and 550. The evolution of the Fanning friction factor f with Re is in very good agreement with experimental measurements. A significant disagreement between the DNS and previous RANS simulations was found in the prediction of the in-plane velocity, and is explained through the inability of the RANS model to properly reproduce the secondary flow present in the hexagon. The kinetic energy of the secondary flow integrated over the cross-sectional area 〈K〉yz decreases with Re in the hexagon, whereas it remains constant with Re in square ducts at comparable Reynolds numbers. Close connection between the values of Reynolds stress uw¯ on the horizontal wall close to the corner and the interaction of bursting events between the horizontal and inclined walls is found. This interaction leads to the formation of the secondary flow, and is less frequent in the hexagon as Re increases due to the 120∘ aperture of its vertex, whereas in the square duct the 90∘ corner leads to the same level of interaction with increasing Re. Analysis of turbulence statistics at the centerplane and the azimuthal variance of the mean flow and the fluctuations shows a close connection between hexagonal ducts and pipe flows, since the hexagon exhibits near-axisymmetric conditions up to a distance of around 0.15DH measured from its center. Spanwise distributions of wall-shear stress show that in square ducts the 90∘ corner sets the location of a high-speed streak at a distance zv+≃50 from it, whereas in hexagons the 120∘ aperture leads to a shorter distance of zv+≃38. At these locations the root mean square of the wall-shear stresses exhibits an inflection point, which further shows the connections between the near-wall structures and the large-scale motions in the outer flow.
Instability of phosphorous doped SiO2 in 4H-SiC MOS capacitors at high temperatures
Authors: Idris M. I. , Weng M. H. , Chan H.-K. , Murphy A. E. , Clark D. T. , Young R. A. R. , Ramsay E. P. , Wright N. G. , Horsfall A. B.
Published: December 2016

In this paper, the effect of inclusion of phosphorous (at a concentration below 1%) on the high temperature characteristics (up to 300 °C) of the SiO2/SiC interface is investigated. Capacitance–voltage measurements taken for a range of frequencies have been utilized to extract parameters including flatband voltage, threshold voltage, effective oxide charge, and interface state density. The variation of these parameters with temperature has been investigated for bias sweeps in opposing directions and a comparison made between phosphorous doped and as-grown oxides. At room temperature, the effective oxide charge for SiO2 may be reduced by the phosphorous termination of dangling bonds at the interface. However, at high temperatures, the effective charge in the phosphorous doped oxide remains unstable and effects such as flatband voltage shift and threshold voltage shift dominate the characteristics. The instability in these characteristics was found to result from the trapped charges in the oxide (±1012 cm−3) or near interface traps at the interface of the gate oxide and the semiconductor (1012–1013 cm−2 eV−1). Hence, the performance enhancements observed for phosphorous doped oxides are not realised in devices operated at elevated temperatures.
Discrete helical modes in imploding and exploding cylindrical, magnetized liners
Authors: Yager-Elorriaga D. A. , Zhang P. , Steiner A. M. , Jordan N. M. , Campbell P. C. , Lau Y. Y. , Gilgenbach R. M.
Published: December 2016

Discrete helical modes have been experimentally observed from implosion to explosion in cylindrical, axially magnetized ultrathin foils (Bz = 0.2 – 2.0 T) using visible self-emission and laser shadowgraphy. The striation angle of the helices, ϕ, was found to increase during the implosion and decrease during the explosion, despite the large azimuthal magnetic field (>40 T). These helical striations are interpreted as discrete, non-axisymmetric eigenmodes that persist from implosion to explosion, obeying the simple relation ϕ = m/kR, where m, k, and R are the azimuthal mode number, axial wavenumber, and radius, respectively. Experimentally, we found that (a) there is only one, or at the most two, dominant unstable eigenmode, (b) there does not appear to be a sharp threshold on the axial magnetic field for the emergence of the non-axisymmetric helical modes, and (c) higher axial magnetic fields yield higher azimuthal modes.
The influence of density in ultracold neutral plasma
Authors: Gao J. W. , Wu Y. , Zhong Z. P. , Wang J. G.
Published: December 2016

We simulate the evolution of ultracold neutral plasmas using molecular dynamics calculations with open boundary conditions. The calculations use 6000 ions and 6000 electrons, respectively, with a quasi-real ion-electron mass ratio of mi/me=1000. The simulated plasmas have both Gaussian and ordered initial distributions. While disorder-induced heating is absent in the initially ordered distributions, the ions are heated significantly by electron-ion collisions. We show that the value of the strong coupling parameter typically falls below 10 for realistic plasma densities.
Comparison of plasma excitation, ionization, and energy influx in single and dual frequency capacitive discharges
Authors: Sahu B. B. , Han Jeon G.
Published: December 2016

Argon (Ar) plasma characteristics in a single and dual-frequency (DF), capacitively coupled plasma processing system are compared for drive frequencies 13.56 MHz, 320 MHz and their mixture as dual frequencies (DF). We present frequency dependent changes that occur in discharges in terms of plasma parameters such as plasma density, electron temperature, electron energy distribution function, optical emission, gas temperature, and metastable Ar density in a pressure range of 10−150 mTorr. Additionally, this work also presents the formulation and characterization of energy fluxes from plasma to a substrate/probe during the plasma generation. By variation of the operating pressure and plasma excitation frequency, the different contributions originating from the kinetic energy, the recombination of charge carriers such as electrons and ions at the surface along with the contributions from the neutral and excited species are determined. Data reveals that Ar metastable density in low-frequency radio frequency (RF) plasma is not a strong function of operating pressure even though plasma ionization increases with pressure. However, in the case of high-frequency and DF, the excitation of Ar metastable decreases and ionization increases due to enhanced collisions and efficient electron-neutral momentum/energy transfer. Also, data reveals that energy flux in the low-frequency RF plasmas is very high compared to that of high-frequency and DF operations.
Counting forbidden patterns in irregularly sampled time series. II. Reliability in the presence of highly irregular sampling
Authors: Sakellariou Konstantinos , McCullough Michael , Stemler Thomas , Small Michael
Published: December 2016

We are motivated by real-world data that exhibit severe sampling irregularities such as geological or paleoclimate measurements. Counting forbidden patterns has been shown to be a powerful tool towards the detection of determinism in noisy time series. They constitute a set of ordinal symbolic patterns that cannot be realised in time series generated by deterministic systems. The reliability of the estimator of the relative count of forbidden patterns from irregularly sampled data has been explored in two recent studies. In this paper, we explore highly irregular sampling frequency schemes. Using numerically generated data, we examine the reliability of the estimator when the sampling period has been drawn from exponential, Pareto and Gamma distributions of varying skewness. Our investigations demonstrate that some statistical properties of the sampling distribution are useful heuristics for assessing the estimator's reliability. We find that sampling in the presence of large chronological gaps can still yield relatively accurate estimates as long as the time series contains sufficiently many densely sampled areas. Furthermore, we show that the reliability of the estimator of forbidden patterns is poor when there is a high number of sampling intervals, which are larger than a typical correlation time of the underlying system.
VQS (vapor-quasiliquid-solid, vapor-quasisolid-solid) mechanism lays down general platform for the syntheses of graphene by chemical vapor deposition
Authors: Noor Mohammad S.
Published: December 2016

Graphene is a relatively new material. The current state-of-the-art of the graphene synthesis has been reviewed. Existing mechanism for the graphene synthesis has been examined. The flaws of this mechanism have been described. Attempts have been made to present a new mechanism called the vapor-quasiliquid (quasisolid)-solid mechanism. For this, various physicochemical processes contributing to graphene synthesis have been considered. These processes include the substrate surface morphology, substrate surface energy, carbon solubility in the substrate surface, temperature, and pressure. Surface disturbance and surface amorphicity of the substrate, together with Knudsen diffusion of the carbon species through this surface, are the key elements of the proposed mechanism. This mechanism appears to have a common platform and a number of ground rules. It describes, for the first time, essentially all possible graphene syntheses, including the synthesis of single-layer, bilayer, few-layer, and multilayer graphene films on all possible substrates, such as metal foils, evaporated metal films, semiconductors, ceramics, and dielectrics. It addresses important features of graphene synthesis as well, namely, the role of permeability, substrate surface orientation, edge effects, etc. The results based on the proposed mechanism are in good agreements with the available experiments.
Ramifications of codoping SrI2:Eu with isovalent and aliovalent impurities
Authors: Feng Qingguo , Biswas Koushik
Published: December 2016

Eu2+ doped SrI2 is an important scintillator having applications in the field of radiation detection. Codoping techniques are often useful to improve the electronic response of such insulators. Using first-principles based approach, we report on the properties of SrI2:Eu and the influence of codoping with aliovalent (Na, Cs) and isovalent (Mg, Ca, Ba, and Sn) impurities. These codopants do not preferably bind with Eu and are expected to remain as isolated impurities in the SrI2 host. As isolated defects they display amphoteric behavior having, in most cases, significant ionization energies of the donor and acceptor levels. Furthermore, the acceptor states of Na, Cs, and Mg can bind with I-vacancy forming charge compensated donor-acceptor pairs. Such pairs may also bind additional holes or electrons similar to the isolated defects. Lack of deep-to-shallow behavior upon codoping and its ramifications will be discussed.
Plasma-based polarization modulator for high-intensity lasers
Authors: Chen Zi-Yu , Pukhov Alexander
Published: December 2016

Manipulation of laser pulses at high intensities is an important yet challenging issue. New types of plasma-based optical devices are promising alternatives to achieve this goal. Here we propose to modulate the polarization state of intense lasers based on oblique reflection from solid-plasma surfaces. A new analytical description is presented considering the plasma as an uniaxial medium that causes birefringence effect. Particle-in-cell simulation results numerically demonstrate that such a scheme can provide a tunable polarization control of the laser pulses even in the relativistic regime. The results are thus relevant for the design of compact, easy to use, and versatile polarization modulators for high-intensity laser pulses.