bluuebunny/crossref_metadata_2025 huggingface dataset:
Aberrant intra- and inter-network connectivity architectures in Alzheimer’s disease and mild cognitive impairment
Authors: Wang Pan , Zhou Bo , Yao Hongxiang , Zhan Yafeng , Zhang Zengqiang , Cui Yue , Xu Kaibin , Ma Jianhua , Wang Luning , An Ningyu , Zhang Xi , Liu Yong , Jiang Tianzi
Published: October 2015

Alzheimer’s disease (AD) patients and those with high-risk mild cognitive impairment are increasingly considered to have dysfunction syndromes. Large-scale network studies based on neuroimaging techniques may provide additional insight into AD pathophysiology. The aim of the present study is to evaluate the impaired network functional connectivity with the disease progression. For this purpose, we explored altered functional connectivities based on previously well-defined brain areas that comprise the five key functional systems [the default mode network (DMN), dorsal attention network (DAN), control network (CON), salience network (SAL), sensorimotor network (SMN)] in 35 with AD and 27 with mild cognitive impairment (MCI) subjects, compared with 27 normal cognitive subjects. Based on three levels of analysis, we found that intra- and inter-network connectivity were impaired in AD. Importantly, the interaction between the sensorimotor and attention functions was first attacked at the MCI stage and then extended to the key functional systems in the AD individuals. Lower cognitive ability (lower MMSE scores) was significantly associated with greater reductions in intra- and inter-network connectivity across all patient groups. These profiles indicate that aberrant intra- and inter-network dysfunctions might be potential biomarkers or predictors of AD progression and provide new insight into AD pathophysiology.
Nanowire CdS-CdTe Solar Cells with Molybdenum Oxide as Contact
Authors: Dang Hongmei , Singh Vijay P.
Published: October 2015

Using a 10 nm thick molybdenum oxide (MoO3−x) layer as a transparent and low barrier contact to p-CdTe, we demonstrate nanowire CdS-CdTe solar cells with a power conversion efficiency of 11% under front side illumination. Annealing the as-deposited MoO3 film in N2 resulted in a reduction of the cell’s series resistance, from 9.97 Ω/cm2 to 7.69 Ω/cm2 and increase in efficiency from 9.9% to 11%. Under illumination from the back, the MoO3−x/Au side, the nanowire solar cells yielded Jsc of 21 mA/cm2 and efficiency of 8.67%. Our results demonstrate use of a thin layer transition metal oxide as a potential way for a transparent back contact to nanowire CdS-CdTe solar cells. This work has implications toward enabling a novel superstrate structure nanowire CdS-CdTe solar cell on Al foil substrate by a low cost roll-to roll fabrication process.
Efficient mass transport by optical advection
Authors: Kajorndejnukul Veerachart , Sukhov Sergey , Dogariu Aristide
Published: October 2015

Advection is critical for efficient mass transport. For instance, bare diffusion cannot explain the spatial and temporal scales of some of the cellular processes. The regulation of intracellular functions is strongly influenced by the transport of mass at low Reynolds numbers where viscous drag dominates inertia. Mimicking the efficacy and specificity of the cellular machinery has been a long time pursuit and, due to inherent flexibility, optical manipulation is of particular interest. However, optical forces are relatively small and cannot significantly modify diffusion properties. Here we show that the effectiveness of microparticle transport can be dramatically enhanced by recycling the optical energy through an effective optical advection process. We demonstrate theoretically and experimentally that this new advection mechanism permits an efficient control of collective and directional mass transport in colloidal systems. The cooperative long-range interaction between large numbers of particles can be optically manipulated to create complex flow patterns, enabling efficient and tunable transport in microfluidic lab-on-chip platforms.
Competition between global warming and an abrupt collapse of the AMOC in Earth’s energy imbalance
Authors: Drijfhout Sybren
Published: October 2015

A collapse of the Atlantic Meridional Overturning Circulation (AMOC) leads to global cooling through fast feedbacks that selectively amplify the response in the Northern Hemisphere (NH). How such cooling competes with global warming has long been a topic for speculation, but was never addressed using a climate model. Here it is shown that global cooling due to a collapsing AMOC obliterates global warming for a period of 15–20 years. Thereafter, the global mean temperature trend is reversed and becomes similar to a simulation without an AMOC collapse. The resulting surface warming hiatus lasts for 40–50 years. Global warming and AMOC-induced NH cooling are governed by similar feedbacks, giving rise to a global net radiative imbalance of similar sign, although the former is associated with surface warming, the latter with cooling. Their footprints in outgoing longwave and absorbed shortwave radiation are very distinct, making attribution possible.
Genome-wide meta-analysis reveals common splice site acceptor variant in CHRNA4 associated with nicotine dependence
Authors: Hancock D B , Reginsson G W , Gaddis N C , Chen X , Saccone N L , Lutz S M , Qaiser B , Sherva R , Steinberg S , Zink F , Stacey S N , Glasheen C , Chen J , Gu F , Frederiksen B N , Loukola A , Gudbjartsson D F , Brüske I , Landi M T , Bickeböller H , Madden P , Farrer L , Kaprio J , Kranzler H R , Gelernter J , Baker T B , Kraft P , Amos C I , Caporaso N E , Hokanson J E , Bierut L J , Thorgeirsson T E , Johnson E O , Stefansson K
Published: October 2015

We conducted a 1000 Genomes–imputed genome-wide association study (GWAS) meta-analysis for nicotine dependence, defined by the Fagerström Test for Nicotine Dependence in 17 074 ever smokers from five European-ancestry samples. We followed up novel variants in 7469 ever smokers from five independent European-ancestry samples. We identified genome-wide significant association in the alpha-4 nicotinic receptor subunit (CHRNA4) gene on chromosome 20q13: lowest P=8.0 × 10−9 across all the samples for rs2273500-C (frequency=0.15; odds ratio=1.12 and 95% confidence interval=1.08–1.17 for severe vs mild dependence). rs2273500-C, a splice site acceptor variant resulting in an alternate CHRNA4 transcript predicted to be targeted for nonsense-mediated decay, was associated with decreased CHRNA4 expression in physiologically normal human brains (lowest P=7.3 × 10−4). Importantly, rs2273500-C was associated with increased lung cancer risk (N=28 998, odds ratio=1.06 and 95% confidence interval=1.00–1.12), likely through its effect on smoking, as rs2273500-C was no longer associated with lung cancer after adjustment for smoking. Using criteria for smoking behavior that encompass more than the single ‘cigarettes per day’ item, we identified a common CHRNA4 variant with important regulatory properties that contributes to nicotine dependence and smoking-related consequences.
Domino intramolecular Diels–Alder reactions to construct a 6/6/5/5 fused tetracyclic framework
Authors: Zhao Gaoyuan , He Min , Li Huilin , Duan Shuangshuang , Yuan Ziyun , Xie Xingang , She Xuegong
Published: October 2015

Heat-promoted domino IMDA reactions to construct a 6/6/5/5 fused tetracyclic framework are developed. Its synthetic application is also demonstrated by an efficient synthesis of 4-epi-hydromitchellene B.
Energy gap engineering of polymeric carbon nitride nanosheets for matching with NaYF4:Yb,Tm: enhanced visible-near infrared photocatalytic activity
Authors: Li Xuefeng , Ren Hao , Zou Zhijuan , Sun Jiaojiao , Wang Jingyu , Liu Zhihong
Published: October 2015

A highly efficient visible-NIR photocatalyst: the electronic structure of CN nanosheets is engineered to match well with the emission energy of UCPs.
Photoinduced water splitting via benzoquinone and semiquinone sensitisation
Authors: Karsili Tolga N. V. , Tuna Deniz , Ehrmaier Johannes , Domcke Wolfgang
Published: October 2015

The splitting of water into H˙ and OH˙ radicals by sensitisation of a redox-active chromophore with sunlight may eventually become a viable way of producing unlimited, clean and sustainable energy.
Structure study of a microemulsion system with an ionic liquid
Authors: Kang Tae Hui , Jeon Yoonnam , Kim Mahn Won
Published: October 2015

A ternary mixture with an IL, C14MIM·Cl, exhibits a great conformational change from single crystal to microemulsion using water.
Branched isomeric 1,2,3-triazolium-based ionic liquids: new insight into structure–property relationships
Authors: Lartey M. , Meyer-Ilse J. , Watkins J. D. , Roth E. A. , Bowser S. , Kusuma V. A. , Damodaran K. , Zhou X. , Haranczyk M. , Albenze E. , Luebke D. R. , Hopkinson D. , Kortright J. B. , Nulwala H. B.
Published: October 2015

Series of branched isomeric 1,2,3-triazolium-based ionic liquids (ILs) were synthesized and characterized. The effect of branching on thermal and physical properties is investigated.
How the spontaneous insertion of amphiphilic imidazolium-based cations changes biological membranes: a molecular simulation study
Authors: Lim Geraldine S. , Jaenicke Stephan , Klähn Marco
Published: October 2015

The insertion of 1-octyl-3-methylimidazolium cations (OMIM+) from a diluted aqueous ionic liquid (IL) solution into a model of a bacterial cell membrane is investigated.
Drastic alteration of diffusioosmosis due to steric effects
Authors: Hoshyargar Vahid , Ashrafizadeh Seyed Nezameddin , Sadeghi Arman
Published: October 2015

We demonstrate essential quantitative and qualitative distinctions between the steric effects on classical electrokinetic phenomena like electroosmosis and on diffusioosmosis.
First efficient catalyst recycling for the iridium-catalysed hydroformylation of 1-octene
Authors: Behr A. , Kämper A. , Kuhlmann R. , Vorholt A. J. , Franke R.
Published: October 2015

This paper describes the development of an efficient catalyst recycling concept for the iridium-catalysed hydroformylation of 1-octene through the investigation of biphasic systems, thermomorphic solvent systems and an ex situ extraction.
Chemo-, regio-, and stereo-selective perfluoroalkylations by a Grignard complex with zirconocene
Authors: Fujiu Motohiro , Negishi Kazuyuki , Guang Jie , Williard Paul G. , Kuroki Shigeki , Mikami Koichi
Published: October 2015

The unique reactivity and high selectivity of the zirconocene-hybridized heterobimetallic perfluoalkyl Grignard reagents can be employed for efficient and highly selective nucleophilic perfluoroalkylation of carbonyl compounds and epoxides, in particular.
Holistic design guidelines for solar hydrogen production by photo-electrochemical routes
Authors: Dumortier Mikaël , Tembhurne Saurabh , Haussener Sophia
Published: October 2015

Device and system design choices for solar energy conversion and storage approaches require holistic design guidelines which simultaneously respect and optimize technical, economic, sustainability, and operating time constraints.
Do ICP-MS based methods fulfill the EU monitoring requirements for the determination of elements in our environment?
Authors: Tirez Kristof , Vanhoof Chris , Bronders Jan , Seuntjens Piet , Bleux Nico , Berghmans Patrick , De Brucker Nicole , Vanhaecke Frank
Published: October 2015

Undoubtedly, the most important advance in the environmental regulatory monitoring of elements of the last decade is the widespread introduction of ICP-mass spectrometry (ICP-MS).
Carbon dioxide capture and utilization: using dinuclear catalysts to prepare polycarbonates
Authors: Yi N. , Unruangsri J. , Shaw J. , Williams C. K.
Published: October 2015

The copolymerization of epoxides, including cyclohexene oxide and vinyl-cyclohexene oxide with carbon dioxide are presented. These processes are catalyzed using a homogeneous di-zinc complex that shows good activity and very high selectivities for polycarbonate polyol formation. The polymerizations are investigated in the presence of different amounts of exogenous reagents, including water, diols and diamines, as models for common contaminants in any carbon dioxide capture and utilization scenario.
Highly efficient single cell arraying by integrating acoustophoretic cell pre-concentration and dielectrophoretic cell trapping
Authors: Kim Soo Hyeon , Antfolk Maria , Kobayashi Marina , Kaneda Shohei , Laurell Thomas , Fujii Teruo
Published: October 2015

We present a novel approach for high throughput single cell arraying by integrating two original microfluidic devices: an acoustofluidic chip and an electroactive microwell array.
Local surface modification via confined electrochemical deposition with FluidFM
Authors: Hirt Luca , Grüter Raphael R. , Berthelot Thomas , Cornut Renaud , Vörös János , Zambelli Tomaso
Published: October 2015

Hollow AFM cantilevers enable local electroplating and grafting followed by thein situimaging of the created surface patterns.
Conditioned bio-interfaces of silicon/porous silicon micro-patterns lead to the chondrogenesis of hMSCs
Authors: Alarcón H. , Ynsa M. D. , Dang Z. Y. , Torres-Costa V. , Manso-Silván M. , Wu J. F. , Breese M. B. H. , García-Ruiz J. P.
Published: October 2015

hMSCs find attractive both Si and PSi surfaces to develop cell-surface adhesions which are needed in differentiation and the presence of CM-hMSCs bio-interface improves the differentiation process with respect to a control PSi surface.
Hyaluronic acid-mediated one-pot facile synthesis of a sensitive and biocompatible Gd2O3 nanoprobe for MR imaging in vivo
Authors: Wang Haoyu , Fu Yan-Yan , Zhang Xuejun , Yu Chunshui , Sun Shao-Kai
Published: October 2015

Hyaluronic acid-mediated synthesis of a Gd2O3 nanoprobe with high r1 and good biocompatibility for MR imaging in vivo.
Enhanced ferroelectricity and energy storage in poly(vinylidene fluoride)–clay nanocomposite films via nanofiller surface charge modulation
Authors: Wang Y. , Li J. , Deng Y.
Published: October 2015

Simultaneous increase in ferroelectricity and energy storage was achieved in pvdf/mmt composite film indicating a good candidate for all-organic electronic devices.
Killing cancer cells by delivering a nanoreactor for inhibition of catalase and catalytically enhancing intracellular levels of ROS
Authors: Kankala Ranjith Kumar , Kuthati Yaswanth , Liu Chen-Lun , Mou Chung-Yuan , Lee Chia-Hung
Published: October 2015

Intracellular hydrogen peroxide levels have the potential to be exploited in cancer therapy.
Synthesis of monodisperse copper nanoparticles using a modified digestive ripening technique and formation of superlattices
Authors: Shaik A. H. , Chakraborty J.
Published: October 2015

Synthesis of very uniform copper nanoparticles and subsequent superlattice formation.
Self-delivery nanoparticles from an amphiphilic covalent drug couple of irinotecan and bendamustine for cancer combination chemotherapy
Authors: Huang Ping , Hu Minxi , Zhou Linzhu , Wang Yao , Pang Yan , Tong Gangsheng , Huang Wei , Su Yue , Zhu Xinyuan
Published: October 2015

We demonstrate an approach to prepare an anticancer drug self-delivery system from an amphiphilic covalent drug couple (Ir–Bd) for cancer combination chemotherapy.
Heat treatment of electrodeposited NiO films for improved catalytic water oxidation
Authors: Basharat F. , Rana U. A. , Shahid M. , Serwar M.
Published: October 2015

The heat treatment of electrodeposited nickel oxide (NiO) films showed remarkable improvements for catalytic water oxidation.
Polyesters derived from bio-based eugenol and 10-undecenoic acid: synthesis, characterization, and structure–property relationships
Authors: Hu Keling , Zhao Dongping , Wu Guolin , Ma Jianbiao
Published: October 2015

A series of thermoplastic polyesters with versatile thermal and mechanical properties were prepared from renewable eugenol, which is extracted from lignocellulosic biomass-clove oil.
Phase transitions and microstructure of ferroelastic MIEC oxide SrCo0.8Fe0.2O2.5 doped with highly charged Nb/Ta(v) cations
Authors: Belenkaya I. V. , Matvienko A. A. , Nemudry A. P.
Published: October 2015

The effect of compositional disorder generated by partial isomorphic substitution of cobalt by ferroactive highly charged cations Nb/Ta(v) on the phase transition “perovskite–brownmillerite”, crystal structure and microstructure of low- and high-temperature phases SrCo0.8−xFe0.2MxO3−δ (M = Nb, Ta; 0 ≤ x ≤ 0.1) was studied for ferroelastic MIEC oxide SrCo0.8Fe0.2O2.5.
Interfacial engineering of self-assembled monolayer modified semi-roll-to-roll planar heterojunction perovskite solar cells on flexible substrates
Authors: Gu Zhuowei , Zuo Lijian , Larsen-Olsen Thue T. , Ye Tao , Wu Gang , Krebs Frederik C. , Chen Hongzheng
Published: October 2015

A self-assembled monolayer is employed to modify the HTL in inverted perovskite solar cells, which results in significant photovoltaic performance enhancement, and can be applied on roll-to-roll fabricated flexible perovskite solar cells.
Biophysical and physiological characterization of ZraP from Escherichia coli, the periplasmic accessory protein of the atypical ZraSR two-component system
Authors: Petit-Härtlein Isabelle , Rome Kevin , de Rosny Eve , Molton Florian , Duboc Carole , Gueguen Erwan , Rodrigue Agnès , Covès Jacques
Published: October 2015

The ZraSR system belongs to the family of TCSs (two-component signal transduction systems). In Escherichia coli, it was proposed to participate in zinc balance and to protect cytoplasmic zinc overload by sequestering this metal ion into the periplasm. This system controls the expression of the accessory protein ZraP that would be a periplasmic zinc scavenger. ZraPSR is functionally homologous with CpxPAR that integrates signals of envelope perturbation, including misfolded periplasmic proteins. The auxiliary periplasmic regulator CpxP inhibits the Cpx pathway by interacting with CpxA. Upon envelope stress sensing, the inhibitory function of CpxP is relieved, resulting in CpxR activation. Similarly to CpxPAR, ZraPSR probably plays a role in envelope stress response as a zinc-dependent chaperone activity was demonstrated for ZraP in Salmonella. We have purified ZraP from E. coli and shown that it is an octamer containing four interfacial metal-binding sites contributing to dimer stability. These sites are located close to the N-terminus, whereas the C-terminus is involved in polymerization of the protein to form a tetramer of dimers. In vitro, ZraP binds copper with a higher affinity than zinc and displays chaperone properties partially dependent on zinc binding. In vivo, zinc-bound ZraP is a repressor of the expression of the zraPSR operon. However, we have demonstrated that none of the Zra proteins are involved in zinc or copper resistance. We propose an integrated mechanism in which zinc is a marker of envelope stress perturbation and ZraPSR TCS is a sentinel sensing and responding to zinc entry into the periplasm.
Consequences of postnatal vascular smooth muscle EGFR deletion on acute angiotensin II action
Authors: Schreier Barbara , Hünerberg Mirja , Rabe Sindy , Mildenberger Sigrid , Bethmann Daniel , Heise Christian , Sibilia Maria , Offermanns Stefan , Gekle Michael
Published: October 2015

Epi dermal growth factor (EGF) receptor (EGFR) is activated by its canonical ligands and transactivated by various vasoactive substances, e.g. angiotensin II (Ang II). Vascular EGFR has been proposed to be involved in vascular tissue homoeostasis and remodelling. Thus, most studies have focused on its role during long-term vascular changes whereas the relevance for acute regulation of vascular function in vivo and ex vivo is insufficiently understood. To investigate the postnatal role of VSMCs (vascular smooth muscle cells) EGFR in vivo and ex vivo, we generated a mouse model with cell-specific and inducible deletion of VSMC EGFR and studied the effect on basal blood pressure, acute pressure response to, among others, Ang II in vivo as well as ex vivo, cardiovascular tissue homoeostasis and vessel morphometry in male mice. In knockout (KO) animals, systolic, diastolic and mean blood pressures were reduced compared with wild-type (WT). Furthermore, Ang II-induced pressure load was lower in KO animals, as was Ang II-induced force development and extracellular-signal-regulated kinase 1 and 2 (ERK1/2) phosphorylation in aortic rings from KO animals. By contrast, we observed no difference in force development during application of serotonin, KCl, endothelin-1 or endothelin-1-induced pressure load in KO animals. In addition, nitric oxide (NO)-mediated vasodilation was not affected. Heart weight (HW) increase and up-regulation of aortic and cardiac expression of Ccl2 (chemoattractant protein-2) and serpinE1 (plasminogen activator inhibitor 1) during the transition from 4- to 10-months of age were prevented by VSMC EGFR KO. We conclude that VSMC EGFR is involved in basal blood pressure homoeostasis and acute pressure response to Ang II, and thereby contributes to maturation-related remodelling.
Smooth control of insulated gate bipolar transistors junction temperature in a small‐scale wind power converter
Authors: Wu Junke , Zhou Luowei , Sun Pengju , Du Xiong
Published: October 2015

In wind power converters, the junction temperature of the power module is the crucial factor which affects its reliability. This study developed a comprehensive thermal management strategy to improve the operational reliability of a small‐scale wind power converter. Firstly, the idea of thermal management that improves the reliability is introduced. Then, in order to smooth the temperature fluctuations, the adjustment law of the switching frequency and the strategy of the exterior thermal management have been investigated. A field‐programmable gate array‐ based thermal management system consists of temperature‐controlled oscillator and fan speed regulator as well as power resistor heating system was designed. Lastly, numerical simulation and experimental implementation were carried out to verify the correctness of the proposed thermal smooth control method.
Integrated dopaminergic neuronal model with reduced intracellular processes and inhibitory autoreceptors
Authors: Cullen Maell , Wong‐Lin KongFatt
Published: October 2015

Dopamine (DA) is an important neurotransmitter for multiple brain functions, and dysfunctions of the dopaminergic system are implicated in neurological and neuropsychiatric disorders. Although the dopaminergic system has been studied at multiple levels, an integrated and efficient computational model that bridges from molecular to neuronal circuit level is still lacking. In this study, the authors aim to develop a realistic yet efficient computational model of a dopaminergic pre‐synaptic terminal. They first systematically perturb the variables/substrates of an established computational model of DA synthesis, release and uptake, and based on their relative dynamical timescales and steady‐state changes, approximate and reduce the model into two versions: one for simulating hourly timescale, and another for millisecond timescale. They show that the original and reduced models exhibit rather similar steady and perturbed states, whereas the reduced models are more computationally efficient and illuminate the underlying key mechanisms. They then incorporate the reduced fast model into a spiking neuronal model that can realistically simulate the spiking behaviour of dopaminergic neurons. In addition, they successfully include autoreceptor‐mediated inhibitory current explicitly in the neuronal model. This integrated computational model provides the first step toward an efficient computational platform for realistic multiscale simulation of dopaminergic systems in in silico neuropharmacology.
Periodontal Bacterial DNA and Their Link to Human Cardiac Tissue: Findings of a Pilot Study
Authors: Ziebolz Dirk , Rost Christoph , Schmidt Julia , Waldmann-Beushausen Regina , Schöndube Friedrich , Mausberg Rainer , Danner Bernhard
Published: October 2015

Background The aim of this pilot study was to detect correlations of microbiological DNA, inflammatory proteins, and infection parameters in patients with periodontal disease (PD) and valvular heart disease (VHD).

Methods A perioperative comprehensive dental examination for the investigation of periodontal status, including sampling of specific subgingival bacteria, was performed in 10 patients with indication for surgery of aortic valve stenosis with or without concomitant myocardial revascularization. Standard protocol biopsies were taken from right atrium (A), left septal myocardium (M), and aortic valve (V). Eleven periodontal pathogens DNA in oral and cardiac tissue samples (A/M/V) were analyzed using polymerase chain reaction. For cardiac tissue samples, Western blot analysis of LPS-binding protein (LBP), immunohistochemical (IHC) detection of LBP-big42, LPS-binding protein receptor (CD14), and macrophages (CD68), as well as inflammation scoring measurement were performed.

Results Periodontitis was present in all patients with severe intensity in 7, moderate in 2 and mild in one patient. Same bacterial DNA was detected in A, M, and V in different distribution, and detection was more often in atrium than in myocardium or valve tissue. Morphological investigation revealed increased extracellular inflammatory cell migration. In IHC markers of LBP, CD68 and CD14 showed positive findings for all patients in atrium and myocardium.

Conclusion Our results demonstrate the presence of oral bacterial DNA in human cardiac tissue, as well as inflammatory markers potentially indicating connection of PD and VHD. Further investigation is necessary to confirm these preliminary data.
Food safety incidents in Beijing: occurrence patterns, causes and wider social implications
Authors: Liu Feiyan , Liu Yang , Gao Jianbo , Zhang Jianfang
Published: October 2015

Food safety incidents have the potential to result in a range of adverse health effects, including diarrhoeal diseases and various forms of cancer. Furthermore, they also have a disruptive effect on the economy, trade and tourism. As Beijing strives to become a global centre of politics, economy and culture, serious food safety incidents continue to be frequently reported in the city. It is clear that a large number of food safety incidents, such as those that have occurred in China, and in some other parts of the world, cannot be fully tackled by means of conventional analysis, which focuses on biological and chemical factors, but which often ignores potential human factors (which may be intentional in nature). In this article, we dynamically examine the time intervals between successive distinct food safety incidents that were mainly caused by human factors. Our intention is to identify information that could be of use to governmental and other bodies in efforts to curb the occurrence of food safety incidents. We analyse data spanning a 10-year period from 2004 to 2013, during which time 295 food safety incidents occurred in Beijing. We find that the occurrence of food safety incidents was drastically different from Poisson processes, suggesting that their causes may have been systemic in nature. We further found that the sequence of time intervals had persistent long-range correlations, characterized by a Hurst parameter of H=0.65, suggesting that food safety incidents occurred in bursts. Finally, we propose scenarios that may be responsible for these long-range correlations. Our quantitative findings may not only hold in Beijing and elsewhere in China, but also in other parts of the world where human factors are an important cause of food safety incidents. In all those situations, our proposed scenarios for long-range correlations may be used as part of efforts to devise strategies to curb or prevent future food safety incidents.
Transition state ensemble optimization for reactions of arbitrary complexity
Authors: Zinovjev Kirill , Tuñón Iñaki
Published: October 2015

In the present work, we use Variational Transition State Theory (VTST) to develop a practical method for transition state ensemble optimization by looking for an optimal hyperplanar dividing surface in a space of meaningful trial collective variables. These might be interatomic distances, angles, electrostatic potentials, etc. Restrained molecular dynamics simulations are used to obtain on-the-fly estimates of ensemble averages that guide the variations of the hyperplane maximizing the transmission coefficient. A central result of our work is an expression that quantitatively estimates the importance of the coordinates used for the localization of the transition state ensemble. Starting from an arbitrarily large set of trial coordinates, one can distinguish those that are indeed essential for the advance of the reaction. This facilitates the use of VTST as a practical theory to study reaction mechanisms of complex processes. The technique was applied to the reaction catalyzed by an isochorismate pyruvate lyase. This reaction involves two simultaneous chemical steps and has a shallow transition state region, making it challenging to define a good reaction coordinate. Nevertheless, the hyperplanar transition state optimized in the space of 18 geometrical coordinates provides a transmission coefficient of 0.8 and a committor histogram well-peaked about 0.5, proving the strength of the method. We have also tested the approach with the study of the NaCl dissociation in aqueous solution, a stringest test for a method based on transition state theory. We were able to find essential degrees of freedom consistent with the previous studies and to improve the transmission coefficient with respect to the value obtained using solely the NaCl distance as the reaction coordinate.
Droplet coalescence and freezing on hydrophilic, hydrophobic, and biphilic surfaces
Authors: Van Dyke Alexander S. , Collard Diane , Derby Melanie M. , Betz Amy Rachel
Published: October 2015

Frost and ice formation can have severe negative consequences, such as aircraft safety and reliability. At atmospheric pressure, water heterogeneously condenses and then freezes at low temperatures. To alter this freezing process, this research examines the effects of biphilic surfaces (surfaces which combine hydrophilic and hydrophobic regions) on heterogeneous water nucleation, growth, and freezing. Silicon wafers were coated with a self-assembled monolayer and patterned to create biphilic surfaces. Samples were placed on a freezing stage in an environmental chamber at atmospheric pressure, at a temperature of 295 K, and relative humidities of 30%, 60%, and 75%. Biphilic surfaces had a significant effect on droplet dynamics and freezing behavior. The addition of biphilic patterns decreased the temperature required for freezing by 6 K. Biphilic surfaces also changed the size and number of droplets on a surface at freezing and delayed the time required for a surface to freeze. The main mechanism affecting freezing characteristics was the coalescence behavior.
Unidirectional oxide hetero-interface thin-film diode
Authors: Park Youngmin , Lee Eungkyu , Lee Jinwon , Lim Keon-Hee , Kim Youn Sang
Published: October 2015

The unidirectional thin-film diode based on oxide hetero-interface, which is well compatible with conventional thin-film fabrication process, is presented. With the metal anode/electron-transporting oxide (ETO)/electron-injecting oxide (EIO)/metal cathode structure, it exhibits that electrical currents ohmically flow at the ETO/EIO hetero-interfaces for only positive voltages showing current density (J)-rectifying ratio of ∼105 at 5 V. The electrical properties (ex, current levels, and working device yields) of the thin-film diode (TFD) are systematically controlled by changing oxide layer thickness. Moreover, we show that the oxide hetero-interface TFD clearly rectifies an AC input within frequency (f) range of 102 Hz < f < 106 Hz, providing a high feasibility for practical applications.
Effect of driving voltages in dual capacitively coupled radio frequency plasma: A study by nonlinear global model
Authors: Bora B.
Published: October 2015

On the basis of nonlinear global model, a dual frequency capacitively coupled radio frequency plasma driven by 13.56 MHz and 27.12 MHz has been studied to investigate the influences of driving voltages on the generation of dc self-bias and plasma heating. Fluid equations for the ions inside the plasma sheath have been considered to determine the voltage-charge relations of the plasma sheath. Geometrically symmetric as well as asymmetric cases with finite geometrical asymmetry of 1.2 (ratio of electrodes area) have been considered to make the study more reasonable to experiment. The electrical asymmetry effect (EAE) and finite geometrical asymmetry is found to work differently in controlling the dc self-bias. The amount of EAE has been primarily controlled by the phase angle between the two consecutive harmonics waveforms. The incorporation of the finite geometrical asymmetry in the calculations shift the dc self-bias towards negative polarity direction while increasing the amount of EAE is found to increase the dc self-bias in either direction. For phase angle between the two waveforms ϕ = 0 and ϕ = π/2, the amount of EAE increases significantly with increasing the low frequency voltage, whereas no such increase in the amount of EAE is found with increasing high frequency voltage. In contrast to the geometrically symmetric case, where the variation of the dc self-bias with driving voltages for phase angle ϕ = 0 and π/2 are just opposite in polarity, the variation for the geometrically asymmetric case is different for ϕ = 0 and π/2. In asymmetric case, for ϕ = 0, the dc self-bias increases towards the negative direction with increasing both the low and high frequency voltages, but for the ϕ = π/2, the dc-self bias is increased towards positive direction with increasing low frequency voltage while dc self-bias increases towards negative direction with increasing high frequency voltage.
Mixed-valence molecular four-dot unit for quantum cellular automata: Vibronic self-trapping and cell-cell response
Authors: Tsukerblat Boris , Palii Andrew , Clemente-Juan Juan Modesto , Coronado Eugenio
Published: October 2015

Our interest in this article is prompted by the vibronic problem of charge polarized states in the four-dot molecular quantum cellular automata (mQCA), a paradigm for nanoelectronics, in which binary information is encoded in charge configuration of the mQCA cell. Here, we report the evaluation of the electronic levels and adiabatic potentials of mixed-valence (MV) tetra-ruthenium (2Ru(ii) + 2Ru(iii)) derivatives (assembled as two coupled Creutz-Taube complexes) for which molecular implementations of quantum cellular automata (QCA) was proposed. The cell based on this molecule includes two holes shared among four spinless sites and correspondingly we employ the model which takes into account the two relevant electron transfer processes (through the side and through the diagonal of the square) as well as the difference in Coulomb energies for different instant positions of localization of the hole pair. The combined Jahn-Teller (JT) and pseudo JT vibronic coupling is treated within the conventional Piepho-Krauzs-Schatz model adapted to a bi-electronic MV species with the square-planar topology. The adiabatic potentials are evaluated for the low lying Coulomb levels in which the antipodal sites are occupied, the case just actual for utilization in mQCA. The conditions for the vibronic self-trapping in spin-singlet and spin-triplet states are revealed in terms of the two actual transfer pathways parameters and the strength of the vibronic coupling. Spin related effects in degrees of the localization which are found for spin-singlet and spin-triplet states are discussed. The polarization of the cell is evaluated and we demonstrate how the partial delocalization caused by the joint action of the vibronic coupling and electron transfer processes influences polarization of a four-dot cell. The results obtained within the adiabatic approach are compared with those based on the numerical solution of the dynamic vibronic problem. Finally, the Coulomb interaction between the cells is considered and the influence of the vibronic coupling on the shape on the non-linear cell-cell response function is revealed.
Solid state amorphization of nanocrystalline nickel by cryogenic laser shock peening
Authors: Ye Chang , Liu Yang , Sang Xiahan , Ren Zhencheng , Zhao Jingyi , Hou Xiaoning , Dong Yalin
Published: October 2015

In this study, complete solid state amorphization in nanocrystalline nickel has been achieved through cryogenic laser shock peening (CLSP). High resolution transmission electron microscopy has revealed the complete amorphous structure of the sample after CLSP processing. A molecular dynamic model has been used to investigate material behavior during the shock loading and the effects of nanoscale grain boundaries on the amorphization process. It has been found that the initial nanoscale grain boundaries increase the initial Gibbs free energy before plastic deformation and also serve as dislocation emission sources during plastic deformation to contribute to defect density increase, leading to the amorphization of pure nanocrystalline nickel.
Retrieval of complex χ(2) parts for quantitative analysis of sum-frequency generation intensity spectra
Authors: Hofmann Matthias J. , Koelsch Patrick
Published: October 2015

Vibrational sum-frequency generation (SFG) spectroscopy has become an established technique for in situ surface analysis. While spectral recording procedures and hardware have been optimized, unique data analysis routines have yet to be established. The SFG intensity is related to probing geometries and properties of the system under investigation such as the absolute square of the second-order susceptibility χ(2)2. A conventional SFG intensity measurement does not grant access to the complex parts of χ(2) unless further assumptions have been made. It is therefore difficult, sometimes impossible, to establish a unique fitting solution for SFG intensity spectra. Recently, interferometric phase-sensitive SFG or heterodyne detection methods have been introduced to measure real and imaginary parts of χ(2) experimentally. Here, we demonstrate that iterative phase-matching between complex spectra retrieved from maximum entropy method analysis and fitting of intensity SFG spectra (iMEMfit) leads to a unique solution for the complex parts of χ(2) and enables quantitative analysis of SFG intensity spectra. A comparison between complex parts retrieved by iMEMfit applied to intensity spectra and phase sensitive experimental data shows excellent agreement between the two methods.
A finger-like hardness tester based on the contact electromechanical impedance of a piezoelectric bimorph cantilever
Authors: Fu Ji , Li Faxin
Published: October 2015

We proposed a finger-like hardness tester based on the electromechanical impedance of a piezoelectric bimorph cantilever. A Vickers indenter was fabricated to the free end of the bimorph to contact the sample. The contact force was monitored by a strain gauge and the contact area was obtained by tracking the bimorph’s resonance frequency. The bimorph-sample contact system was modeled by the electromechanical equivalent circuit method. Verification experiments on standard hardness samples were conducted and the measured hardness values agreed well with those given by a conventional Vickers hardness tester. Further hardness measurement on a gear wheel showed that the proposed hardness tester is very adaptive and can be used for inner surface testing or in situ testing, where other hardness testers may not be applicable. The proposed hardness tester can be regarded as an improved ultrasonic hardness tester.
Radiation defect dynamics in Si at room temperature studied by pulsed ion beams
Authors: Wallace J. B. , Charnvanichborikarn S. , Bayu Aji L. B. , Myers M. T. , Shao L. , Kucheyev S. O.
Published: October 2015

The evolution of radiation defects after the thermalization of collision cascades often plays the dominant role in the formation of stable radiation disorder in crystalline solids of interest to electronics and nuclear materials applications. Here, we explore a pulsed-ion-beam method to study defect interaction dynamics in Si crystals bombarded at room temperature with 500 keV Ne, Ar, Kr, and Xe ions. The effective time constant of defect interaction is measured directly by studying the dependence of lattice disorder, monitored by ion channeling, on the passive part of the beam duty cycle. The effective defect diffusion length is revealed by the dependence of damage on the active part of the beam duty cycle. Results show that the defect relaxation behavior obeys a second order kinetic process for all the cases studied, with a time constant in the range of ∼4–13 ms and a diffusion length of ∼15–50 nm. Both radiation dynamics parameters (the time constant and diffusion length) are essentially independent of the maximum instantaneous dose rate, total ion dose, and dopant concentration within the ranges studied. However, both the time constant and diffusion length increase with increasing ion mass. This demonstrates that the density of collision cascades influences not only defect production and annealing efficiencies but also the defect interaction dynamics.
Balmer-α spectrum measurements of the LHD one-third ion source
Authors: Wada M. , Kenmotsu T. , Kisaki M. , Nakano H. , Nishiura M. , Tsumori K.
Published: October 2015

Wavelength spectra of Balmer-α light from plasmas in the extraction region of the Large Helical Device-R&D negative ion source, or the LHD one-third ion source have exhibited a blue shift as a negative bias voltage was applied to the plasma grid. The blue shift increased as the negative bias voltage with respect to the local plasma potential was increased. The measured spectra were compared with the velocity distributions of surface reflected hydrogen atoms calculated by atomic collisions in amorphous target code. The arc power and the source H2 pressure also affected the shift and broadening in the observed Balmer-α spectra. The possibility of identifying the negative hydrogen ions produced at the low work function plasma grid surface by high resolution spectroscopy is discussed.
Instability growth for magnetized liner inertial fusion seeded by electro-thermal, electro-choric, and material strength effects
Authors: Pecover J. D. , Chittenden J. P.
Published: October 2015

A critical limitation of magnetically imploded systems such as magnetized liner inertial fusion (MagLIF) [Slutz et al., Phys. Plasmas 17, 056303 (2010)] is the magneto-Rayleigh-Taylor (MRT) instability which primarily disrupts the outer surface of the liner. MagLIF-relevant experiments have showed large amplitude multi-mode MRT instability growth growing from surface roughness [McBride et al., Phys. Rev. Lett. 109, 135004 (2012)], which is only reproduced by 3D simulations using our MHD code Gorgon when an artificially azimuthally correlated initialisation is added. We have shown that the missing azimuthal correlation could be provided by a combination of the electro-thermal instability (ETI) and an “electro-choric” instability (ECI); describing, respectively, the tendency of current to correlate azimuthally early in time due to temperature dependent Ohmic heating; and an amplification of the ETI driven by density dependent resistivity around vapourisation. We developed and implemented a material strength model in Gorgon to improve simulation of the solid phase of liner implosions which, when applied to simulations exhibiting the ETI and ECI, gave a significant increase in wavelength and amplitude. Full circumference simulations of the MRT instability provided a significant improvement on previous randomly initialised results and approached agreement with experiment.
Multi-scaled normal mode analysis method for dynamics simulation of protein-membrane complexes: A case study of potassium channel gating motion correlations
Authors: Wu Xiaokun , Han Min , Ming Dengming
Published: October 2015

Membrane proteins play critically important roles in many cellular activities such as ions and small molecule transportation, signal recognition, and transduction. In order to fulfill their functions, these proteins must be placed in different membrane environments and a variety of protein-lipid interactions may affect the behavior of these proteins. One of the key effects of protein-lipid interactions is their ability to change the dynamics status of membrane proteins, thus adjusting their functions. Here, we present a multi-scaled normal mode analysis (mNMA) method to study the dynamics perturbation to the membrane proteins imposed by lipid bi-layer membrane fluctuations. In mNMA, channel proteins are simulated at all-atom level while the membrane is described with a coarse-grained model. mNMA calculations clearly show that channel gating motion can tightly couple with a variety of membrane deformations, including bending and twisting. We then examined bi-channel systems where two channels were separated with different distances. From mNMA calculations, we observed both positive and negative gating correlations between two neighboring channels, and the correlation has a maximum as the channel center-to-center distance is close to 2.5 times of their diameter. This distance is larger than recently found maximum attraction distance between two proteins embedded in membrane which is 1.5 times of the protein size, indicating that membrane fluctuation might impose collective motions among proteins within a larger area. The hybrid resolution feature in mNMA provides atomic dynamics information for key components in the system without costing much computer resource. We expect it to be a conventional simulation tool for ordinary laboratories to study the dynamics of very complicated biological assemblies. The source code is available upon request to the authors.
Thickness dependence of La0.7Sr0.3MnO3/PbZr0.2Ti0.8O3 magnetoelectric interfaces
Authors: Zhou Jinling , Tra Vu Thanh , Dong Shuai , Trappen Robbyn , Marcus Matthew A. , Jenkins Catherine , Frye Charles , Wolfe Evan , White Ryan , Polisetty Srinivas , Lin Jiunn-Yuan , LeBeau James M. , Chu Ying-Hao , Holcomb Mikel Barry
Published: October 2015

Magnetoelectric materials have great potential to revolutionize electronic devices due to the coupling of their electric and magnetic properties. Thickness varying La0.7Sr0.3MnO3 (LSMO)/PbZr0.2Ti0.8O3 (PZT) heterostructures were built and measured in this article by valence sensitive x-ray absorption spectroscopy. The sizing effects of the heterostructures on the LSMO/PZT magnetoelectric interfaces were investigated through the behavior of Mn valence, a property associated with the LSMO magnetization. We found that Mn valence increases with both LSMO and PZT thickness. Piezoresponse force microscopy revealed a transition from monodomain to polydomain structure along the PZT thickness gradient. The ferroelectric surface charge may change with domain structure and its effects on Mn valence were simulated using a two-orbital double-exchange model. The screening of ferroelectric surface charge increases the electron charges in the interface region, and greatly changes the interfacial Mn valence, which likely plays a leading role in the interfacial magnetoelectric coupling. The LSMO thickness dependence was examined through the combination of two detection modes with drastically different attenuation depths. The different length scales of these techniques' sensitivity to the atomic valence were used to estimate the depth dependence Mn valence. A smaller interfacial Mn valence than the bulk was found by globally fitting the experimental results.