bluuebunny/crossref_metadata_2025 huggingface dataset:
Simultaneous analysis of 25OHD3 and 24,25(OH)2D3 both in human serum and cerebrospinal fluid by LC-MS/MS
Authors: He Xin , Jiang Pei , Xue Ying , Zhu Wen-Ye , Deng Yang , Yan Miao , Li Huan-De , Dang Rui-Li , Tang Mi-Mi
Published: February 2016

The derivatization reaction between analytes, 25(OH)D3 and 24,25(OH)2D3, and PTAD highly increased their ionization efficiency and molecular weight, thereby the lower limit of quantification was reduced and the sensitivity of determination was considerably enhanced.
A fluorescent probe based on N-doped carbon dots for highly sensitive detection of Hg2+ in aqueous solutions
Authors: Gao Zhi-hao , Lin Zheng-zhong , Chen Xiao-mei , Zhong Hui-ping , Huang Zhi-yong
Published: February 2016

The UV-Vis absorption spectrum (left) and fluorescence excitation and emission spectra (right) of NCDs.
Rational design of hybridization chain reaction monomers for robust signal amplification
Authors: Ang Yan Shan , Yung Lin-Yue Lanry
Published: February 2016

Four-point design guidelines for generating robust hybridization chain reaction (HCR) hairpin sequences were established and successfully implemented for FRET readout.
Oxidation of cholesterol and O-protected derivatives by the environmental pollutant NO2˙
Authors: Zalewski A. N. , Nathanael J. G. , White J. M. , Wille U.
Published: February 2016

Exposure ofO-protected and free cholesterol to NO2˙ leads to oxidation of the alkene moiety through non-radical pathways, demonstrating that ionic processes must be considered when assessing NO2˙ toxicity.
Pure white light emission from organic molecules using solvent induced selective self-assembly
Authors: Malakar Partha , Modak Debadrita , Prasad Edamana
Published: February 2016

Selectively promoting and preventing aggregation of structurally similar anthracene derivatives to obtain pure white light emission.
Adjusting the thermoelectric properties of copper(i) oxide–graphite–polymer pastes and the applications of such flexible composites
Authors: Andrei Virgil , Bethke Kevin , Rademann Klaus
Published: February 2016

We present in our manuscript the full path from concept to characterization, optimization and application of thermoelectric pastes.
Toward fluorine-free blue-emitting cationic iridium complexes: to generate emission from the cyclometalating ligands with enhanced triplet energy
Authors: He Lei , Wang Zhen , Duan Lian , Yang Chunpeng , Tang Ruiren , Song Xiangzhi , Pan Chunyue
Published: February 2016

Generating emission from cyclometalating ligands with enhanced triplet energy is an efficient avenue toward fluorine-free blue-emitting cationic iridium complexes.
The beneficial effects of taurine in preventing metabolic syndrome
Authors: Chen Wen , Guo Junxia , Zhang Yanzhen , Zhang Jing
Published: February 2016

A review of the data fromin vitro, animal and limited human studies of the beneficial effects of taurine on obesity, dyslipidaemia, diabetes mellitus and hypertension, as well as the possible metabolic and molecular mechanisms for the prevention of metabolic syndrome by taurine.
Precise measurement of stable potassium isotope ratios using a single focusing collision cell multi-collector ICP-MS
Authors: Li Weiqiang , Beard Brian L. , Li Shilei
Published: February 2016

High precision potassium isotope ratio measurements were made using a collision-cell equipped single focusing Multi-Collector Inductively Coupled Plasma Mass Spectrometer (MC-ICP-MS).
The preparation of modified boehmite/PMMA nanocomposites by in situ polymerization and the assessment of their capability for Cu2+ ion removal
Authors: Mohammadnezhad Gholamhossein , Dinari Mohammad , Soltani Roozbeh
Published: February 2016

The addition of nanoboehmite as a nanofiller into the polymer matrix led to the improvement of the thermal properties and increased the active sites of nanocomposites for Cu(ii) removal.
3-Acylated tetramic and tetronic acids as natural metal binders: myth or reality?
Authors: Zaghouani Mehdi , Nay Bastien
Published: February 2016

Stable salts and chelates of 3-acylated tetramic and tetronic acids could be prevalent under natural and physiological conditions, suggesting their importance for biological activities.
Multi-conformer molecules in solutions: an NMR-based DFT/MP2 conformational study of two glucopyranosides of a vitamin E model compound
Authors: Nazarski Ryszard B. , Wałejko Piotr , Witkowski Stanisław
Published: February 2016

Overall geometries of both glucosyl derivatives of PMC were found on the basis of their NMR spectra in CDCl3and relatedδH,C/nJHHIEF-PCM(UFF,CHCl3)/DFT calculational results.
Enhanced catalytic activity of oxovanadium complexes in oxidative polymerization of diphenyl disulfide
Authors: Aida Fuyuki , Takatori Yohei , Kiyokawa Daichi , Nagamatsu Kentaro , Oyaizu Kenichi , Nishide Hiroyuki
Published: February 2016

The first VO(salen) catalyzed oxidative polymerization of PhSSPh and bromanil-assisted acceleration of the polymerization were reported.
Highly efficient conversion of microcrystalline cellulose to 5-hydroxymethyl furfural in a homogeneous reaction system
Authors: Zhang Yan-Ru , Li Nan , Li Ming-Fei , Fan Yong-Ming
Published: February 2016

A homogenous reaction system with zinc chloride hydrate was explored for the synthesis of 5-HMF from MCC.
Removal of Rhodamine B from water by using CdTeSe quantum dot-cellulose membrane composites
Authors: Baslak Canan , Arslan Gulsin , Kus Mahmut , Cengeloglu Yunus
Published: February 2016

Facilitated transport of Rhodamine B through a novel polymer inclusion membrane (PIM) containing CdTeSe Quantum Dots (QDs) as a carrier reagent has been investigated.
Aceclofenac–β-cyclodextrin-vesicles: a dual carrier approach for skin with enhanced stability, efficacy and dermatokinetic profile
Authors: Sharma Gajanand , Kaur Manmeet , Raza Kaisar , Thakur Kanika , Katare O. P.
Published: February 2016

The aim of the current investigation was to develop and characterize lipid-based carriers of aceclofenac (ACE) with enhanced stability and transdermal delivery potential to the inflammatory sites in osteoarthritis.
Catalytic application of non-toxic Persia americana metabolite entrapped SnO2nanoparticles towards the synthesis of 3,4-dihydroacridin-1(2H)-ones
Authors: Roopan Selvaraj Mohana , Palaniraja Jeyakannu , Elango Ganesh , Arunachalam Prabhakarn , Sudhakaran R.
Published: February 2016

Synthesized green SnO2NPs were utilized in organic synthesis. Catalytic application was explored to synthesize 3,4-dihydroacridin-1(2H)-ones.
Molecular dynamics studying on welding behavior in thermosetting polymers due to bond exchange reactions
Authors: Yang Hua , Yu Kai , Mu Xiaoming , Wei Yujie , Guo Yafang , Qi H. Jerry
Published: February 2016

The surfaces of covalent adaptable network polymers can be welded together through bond exchange reactions occurring at the interface, resulting in new bonds crossing the interface and connecting the two materials.
The synthetic effect on volatile fatty acid disinhibition and methane production enhancement by dosing FeCl3in a sludge thermophilic anaerobic digestion system
Authors: Yu Bao , Zhang Dongling , Dai Xiaohu , Lou Ziyang , Yuan Haiping , Zhu Nanwen
Published: February 2016

A dosage gradient of FeCl3was adopted and 9.92 mg Fe per g DS was favorable for the disinhibition of VFAs in sludge thermophilic digestion system.
Primary investigation of the optical limiting performance of cyclo[8]pyrrole with a wide optical limiting window
Authors: Xu H. , Zhao S. Q. , Ren Y. , Xu W. , Zhu D. B. , Jiang J. Z. , Cai J. F.
Published: February 2016

Cyclo[8]pyrrole (CP) was prepared and its UV/vis spectral and optical limiting properties for ns light pulse were investigated withZ-scan technical.
Non-enzymatic electrochemical sensing of glucose and hydrogen peroxide using a bis(acetylacetonato)oxovanadium(iv) complex modified gold electrode
Authors: Barman Koushik , Jasimuddin Sk
Published: February 2016

A bis(acetylacetonato)oxovanadium(iv) complex modified gold electrode shows excellent sensing ability towards glucose and hydrogen peroxide in a neutral pH medium.
Acid-promoted rapid solvent-free access to substituted 1,4-dihydropyridines from β-ketothioamides
Authors: Li Ming , Sun Ke-Na , Wen Li-Rong
Published: February 2016

1,4-Dihydropyridines were synthesized via a tandem reaction of β-ketothioamides with aldehydes and β-enaminonitriles by AcOH as a promoter within 5 min.
Improved charge separation and transport efficiency in panchromatic-sensitized solar cells with co-sensitization of PbS/CdS/ZnS quantum dots and dye molecules
Authors: Luo Songping , Shen Heping , Hu Wei , Yao Zhibo , Li Jianbao , Oron Dan , Wang Ning , Lin Hong
Published: February 2016

Schematic energy diagram of carrier generation, transfer, and recombination in the TiO2/PbS/CdS/ZnS/N719 film.
An enzyme–copper nanoparticle hybrid catalyst prepared from disassembly of an enzyme–inorganic nanocrystal three-dimensional nanostructure
Authors: Li Zhixian , Ding Yi , Wu Xiaoling , Ge Jun , Ouyang Pingkai , Liu Zheng
Published: February 2016

Enzyme–copper nanoparticle hybrid catalysts were prepared with highly retained enzymatic and Cu-catalytic activities, enabling the chemo-enzymatic cascade reactions.
Peptidines: glycine-amidine-based oligomers for solution- and solid-phase synthesis
Authors: Vastl Julian , Kartika Rendy , Park Kichul , Cho Art E. , Spiegel David A.
Published: February 2016

We introduce a modular synthetic procedure to produce a new class of synthetic oligomers called peptidines composed of repeating di-substituted glycine-derived amidines.
Protein release from highly charged peptide hydrogel networks
Authors: Nagy-Smith Katelyn , Yamada Yuji , Schneider Joel P.
Published: February 2016

Highly charged hydrogel networks from self-assembling peptides allow electrostatic-based control over protein release under physiological buffer conditions.
Solid-phase extraction followed by gas chromatography-mass spectrometry for the quantitative analysis of semi-volatile hydrocarbons in hydraulic fracturing wastewaters
Authors: Regnery Julia , Coday Bryan D. , Riley Stephanie M. , Cath Tzahi Y.
Published: February 2016

A versatile method was developed for the quantitative analysis of semi-volatile linear aliphatic hydrocarbons in the n-C10 to n-C32 range and 16 PAH in hydraulic fracturing wastewaters using C18 SPE followed by GC-MS.
Fluorescence anisotropy assay ford-vasopressin with a tetramethylrhodamine-labeled aptamer
Authors: Liu Yingxiong , Zhao Qiang
Published: February 2016

Fluorescence anisotropy analysis ofD-vasopressin was achieved by using a tetramethylrhodamine (TMR) labeled aptamer based on the binding-induced change of FA of TMR.
Introducing asymmetric functionality into MOFs via the generation of metallic Janus MOF particles
Authors: Ayala Abraham , Carbonell Carlos , Imaz Inhar , Maspoch Daniel
Published: February 2016

Metallic Janus MOF particles are engineered to impart asymmetric functionalities to MOFs, including asymmetric functionalization, magnetic-guidance and motorization.
Click chemistry functionalization improving the wideband optical-limiting performance of fullerene derivatives
Authors: Liu Xiong , Wang Dong , Gao Hong , Yang Zhou , Xing Yan , Cao Hui , He Wanli , Wang Huihui , Gu Jianming , Hu Huiying
Published: February 2016

A novel kind of monodonor–bisacceptor (D–A–A) C60 charge-transfer complex was synthesized by the high-yielding [2+2] click chemistry reaction and the Prato reaction.
Fluid transition layer between rigid solute and liquid solvent: is there depletion or enrichment?
Authors: Djikaev Yuri S. , Ruckenstein Eli
Published: February 2016

The fluid layer between solute and liquid solvent is studied by combining the density functional theory with the probabilistic hydrogen bond model.
Rare-earth-free red-emitting K2Ge4O9:Mn4+phosphor excited by blue light for warm white LEDs
Authors: Ding Xin , Wang Qian , Wang Yuhua
Published: February 2016

We report a K2Ge4O9:Mn4+phosphor that can be excited by blue light for application in warm white LEDs.
Artificial micro-swimmers in simulated natural environments
Authors: Katuri J. , Seo K. D. , Kim D. S. , Sánchez S.
Published: February 2016

In this Focus article, we summarize recent observations of artificial swimmers in chemical gradients, shear flows and other interesting natural environments simulated in the lab using microfluidics and nanotechnology.
Transition-metal free thiocyanooxygenation of functionalized alkenes: facile routes to SCN-containing dihydrofurans and lactones
Authors: Guo Li-Na , Gu Yu-Rui , Yang Hua , Hu Jie
Published: February 2016

An efficient transition-metal free tandem cyclization of functionalized alkenes with thiocyanate salts has been developed under mild conditions. This protocol offers a simple, easy-to-handle, and atom-economical method for the synthesis of SCN-containing dihydrofurans and lactones with good to excellent yields.
Synthesis of chitosan/PEO/silica nanofiber coating for controlled release of cefepime from implants
Authors: Pebdeni Azam Bagheri , Sadri Minoo , Pebdeni Sajjad Bagheri
Published: February 2016

Nanofibers, which have good properties such as high surface to volume ratio, high porosity, very small pores, and the ability to load drugs, can be considered for a variety of medical applications.
Effects of GO oxidation degree on GO/BuMgCl-supported Ti-based Ziegler–Natta catalyst performance and nanocomposite properties
Authors: Zhang He-Xin , Bae Min-Gi , Park Jae-Hyeong , Ko Eun-Bin , Lee Dong-Ho , Zhang Xue-Quan , Yoon Keun-Byoung
Published: February 2016

The effects of GO oxidation degree on catalyst performance were studied. The resultant PE/rGO product exhibited significant increase in mechanical properties of commercial PE due to the well dispersion and good interface adhesion with the PE matrix.
Strange critical behaviors of ferromagnetic to paramagnetic transition in La0.5Ca0.5MnO3 nanowires bundles
Authors: Fang Fei , Hong Bo , Ling Langsheng , Xu Jingcai , Jin Hongxiao , Jin Dingfeng , Peng Xiaoling , Li Jing , Yang Yanting , Wang Xinqing
Published: February 2016

La0.5Ca0.5MnO3 nanowire bundles were synthesized by a hard template method, followed by further investigation on their strange critical behaviors.
Facile one-pot three-component synthesis of diverse 2,3-disubstituted isoindolin-1-ones using ZrO2 nanoparticles as a reusable dual acid–base solid support under solvent-free conditions
Authors: Debnath Kamalesh , Mukherjee Sayan , Bodhak Chandan , Pramanik Animesh
Published: February 2016

A series of multi-functionalized 2,3-disubstituted isoindolin-1-ones has been synthesized using ZrO2 nanoparticles as a dual acid–base solid support under solvent-free conditions.
Highly scalable production of uniformly-coated superparamagnetic nanoparticles for triggered drug release from alginate hydrogels
Authors: Teleki Alexandra , Haufe Florian L. , Hirt Ann M. , Pratsinis Sotiris E. , Sotiriou Georgios A.
Published: February 2016

Large-scale production of SiO2-coated Fe2O3nanoparticles facilitates their incorporation in stimuli-responsive superparamagnetic alginate hydrogel structures with efficient hyperthermia performance and enhanced triggered drug release.
Conjugated polymer-enhanced enantioselectivity in fluorescent sensing
Authors: Zhang Xuepeng , Wang Chao , Wang Pan , Du Jiajun , Zhang Guoqing , Pu Lin
Published: February 2016

A new strategy to use conjugated polymers to conduct fluorescent enhancement sensing has been developed.
Nanoporous polysulfone membranes via a degradable block copolymer precursor for redox flow batteries
Authors: Gindt B. P. , Abebe D. G. , Tang Z. J. , Lindsey M. B. , Chen J. , Elgammal R. A. , Zawodzinski T. A. , Fujiwara T.
Published: February 2016

Nanoporous membrane templates were prepared from self-assembled block copolymers composed of polysulfone and degradable polylactide blocks. The pore surface in the template was modified with sulfonic acid groups. The membranes were evaluated in a vanadium redox battery.
Adjoint operator‐based isomorphism realisation and control design for non‐linear systems
Authors: Tao Fazhan , Deng Mingcong
Published: February 2016

In this study, a realisation to robust right coprime factorisation and robust stability of non‐linear systems with unknown bounded perturbations are investigated based on inner product of Hilbert spaces. In detail, first, a feasible framework based on inner product is proposed to study robust right factorisation of the perturbed non‐linear systems, which provides fundamental for factorising the systems and guaranteeing robust stability. Second, a condition based on adjoint operators of Hilbert spaces is given for the non‐linear systems with unknown bounded perturbations, according to which a compensator is designed and meanwhile eliminates difficulties in obtaining internal signal of the perturbed non‐linear systems. After that, a realisable design scheme on robust stability is given based on the designed controller and the unimordular property. According to the proposed robust design scheme, the non‐linear systems with unknown bounded perturbations can be handled precisely and effectively. Finally, a simulation example is given to confirm the effectiveness of the proposed methods.
Investigation of transformer banks with delta‐connected secondary windings and various grounding methods for delta service
Authors: Chen Tsai‐Hsiang , Liao Rih‐Neng
Published: February 2016

Grounding at source transformers or generators in a distribution system can help to stabilise system voltages and enhance overall reliability and safety. However, the operational characteristics of a distribution system depend on the type of grounding method employed. This study examines the operation characteristics of three‐phase transformer banks with delta‐connected secondary windings using a variety of grounding methods for three‐phase three‐wire or three‐phase four‐wire delta secondary services. The grounding methods investigated in this study include two conventional methods and a neutral grounding structure, called grounding winding. The authors began by developing coupling‐free equivalent circuits of three‐phase transformer banks with delta‐connected secondary windings in accordance with the network‐overlapping technique and circuit theory. These equivalent circuits faithfully reflect the features of the transformer banks with the various grounding methods. Then they implemented coupling‐free equivalent circuits using the software package MATLAB/Simulink to verify the suitability of the equivalent circuits for this study. The authors’ analytical results reveal that this neutral grounding structure provides a solid system neutral through a grounding winding as well as a voltage steadier than that obtained under ungrounded conditions or using corner‐grounding or mid‐tap grounding. Their results provide a valuable reference for power engineers seeking a suitable grounding method for delta service systems.
Digital resonant controller for dual‐stage photovoltaic inverter system with small dc‐bus capacitor
Authors: Reiter Renan Diego de Oliveira , Oliveira Sérgio Vidal Garcia , Péres Adriano , Michels Leandro
Published: February 2016

Electrolitic capacitors of dc‐bus link normally present the lowest mean time between failures among other electronic components of photovoltaic (PV) inverters. This manuscript proposes to increase inverter reliability using a dual‐stage PV inverter system with small dc‐bus link film capacitors, where a high‐gain high‐frequency isolated step‐up dc–dc converter processes the energy from PV arrays. This converter topology in combination with a digital resonant control strategy for elimination of the low‐frequency power ripple in PV array makes possible reducing dc‐bus link capacitance without reduction of power extracted from PV system. The proposed control system is explained in detail, including experimental validation.
Characteristics analysis of a new single‐phase π‐type five‐level inverter
Authors: Hu Yanshen , Xie Yunxiang , Cheng Li , Fu Dianbo
Published: February 2016

The characteristics analysis of a new single‐phase π‐type five‐level inverter using three‐terminal switch‐network is proposed in this study. The topology is the variant of three‐level T‐type topology or multi‐level inverter using interleaved pulse width modulation (PWM) in a bridge‐leg with coupled inductors. Moreover, the big merit of the new inverter is to apply only four active power switches to achieve five‐level operations resulted in high efficiency and low harmonics. Furthermore, double‐frequency operation of output inductors and equal division of the current that flows through power switches and filter inductor also can be achieved. These characteristics allow improvement of losses distribution, voltage and volume reduction of output filter inductor. The operation scenario with sinusoidal PWM is described in details. Meanwhile, the magnetic analysis and design, dc bias component evaluation in the magnetising current, stresses analyses and power losses calculation of power switches are studied and discussed. Finally, the simulation and prototype experiment demonstrate the advantages of the proposed topology.
Intensity‐tunable guided mode resonance reflectance filter with dual channels
Authors: Li Ye , Wang Qi , Zhang Dawei , Wang Jianyu , Chen Peng , Dai Bo , Huang Yuanshen , Tao Chunxian , Sheng Bin
Published: February 2016

An intensity‐tunable reflectance filter with an unetched grating that is based on guided mode resonance is proposed. The unetched grating is designed for simplifying the fabrication proceeds and avoiding the errors of etching. The dual resonant wavelength channels are calculated by rigorous coupled‐wave analysis to be at 747.3 and 786.5 nm. Theoretical and experimental data indicate that the intensity of the spectral reflectance at the peak wavelength of 747.3 nm increases monotonically with variation of the azimuthal angle from 0° to 90°. Conversely, the intensity of the spectral reflectance decreases monotonically under the same conditions at the resonant wavelength of 786.5 nm. It is found experimentally that the intensity can be tuned via the azimuthal angles, and this agrees well with the results of the theoretical analysis. In addition, the influence of the structural parameters on the value of the wavelength separation between the dual resonance channels is analysed, and the electric field distributions at the resonant wavelengths are presented.
How Does Severity of Aphasia Influence Individual Responsiveness to Rehabilitation? Using Big Data to Understand Theories of Aphasia Rehabilitation
Authors: Kiran Swathi
Published: February 2016

Our ability to make great progress in delivering, optimizing, and predicting rehabilitation outcomes for individuals with aphasia is challenged by factors that influence rehabilitation outcomes. These include patient demographic factors such as age, education, and neurologic factors such as time poststroke, the site and size of the lesion, and the resulting severity of language impairment. Also variable across individuals is the type of treatment and its duration and intensity. This article examines the utility of big data analysis for understanding one of these factors, severity of impairment, and how individual responsiveness to rehabilitation is influenced by a patient's severity of language and cognitive impairment(s). Using examples from two studies and a larger data set, we show that when rehabilitation is tailored to an individual's specific level of impairment, severe and mild patients both show improvements in accuracy and latency. Furthermore, more severe patients tend to show substantial gains on targeted rehabilitation tasks as well as on standardized tests. These results provide support for recent reviews of aphasia rehabilitation studies in concluding that systematic aphasia rehabilitation is indeed effective, and importantly, severity is not a negative prognostic indicator for successful outcomes.
Absolute vibrational cross sections for 1-19 eV electron scattering from condensed tetrahydrofuran (THF)
Authors: Lemelin V. , Bass A. D. , Cloutier P. , Sanche L.
Published: February 2016

Absolute cross sections (CSs) for vibrational excitation by 1–19 eV electrons impacting on condensed tetrahydrofuran (THF) were measured with a high-resolution electron energy loss spectrometer. Experiments were performed under ultra-high vacuum (3 × 10−11 Torr) at a temperature of about 20 K. The magnitudes of the vibrational CSs lie within the 10−17 cm2 range. Features observed near 4.5, 9.5, and 12.5 eV in the incident energy dependence of the CSs were compared to the results of theoretical calculations and other experiments on gas and solid-phase THF. These three resonances are attributed to the formation of shape or core-excited shape resonances. Another maximum observed around 2.5 eV is not found in the calculations but has been observed in gas-phase studies; it is attributed to the formation of a shape resonance.
Diffusions conditioned on occupation measures
Authors: Angeletti Florian , Touchette Hugo
Published: February 2016

A Markov process fluctuating away from its typical behavior can be represented in the long-time limit by another Markov process, called the effective or driven process, having the same stationary states as the original process conditioned on the fluctuation observed. We construct here this driven process for diffusions spending an atypical fraction of their evolution in some region of state space, corresponding mathematically to stochastic differential equations conditioned on occupation measures. As an illustration, we consider the Langevin equation conditioned on staying for a fraction of time in different intervals of the real line, including the positive half-line which leads to a generalization of the Brownian meander problem. Other applications related to quasi-stationary distributions, metastable states, noisy chemical reactions, queues, and random walks are discussed.
Density measurements of subcooled water in the temperature range of (243 and 283) K and for pressures up to 400 MPa
Authors: Romeo Raffaella , Giuliano Albo P. Alberto , Lorefice Salvatore , Lago Simona
Published: February 2016

In this work, accurate density measurements of subcooled water (freshly double-distilled water) were performed along eight constant-mass curves in the temperature range of (243 to 283) K and in the pressure range of (140 to 400) MPa, by a pseudo-isochoric method. The experimental apparatus mainly consisted of a high pressure vessel, especially designed for this experiment, of known volume as a function of temperature and pressure, used to perform measurements in the T-p range under study. The density of subcooled water was obtained by measuring the equilibrium pressure at different temperatures, keeping the mass constant. All terms contributing to the uncertainty of subcooled water density measurements were considered; the estimated relative uncertainty, in the investigated temperature and pressure range, is about 0.07%. The experimental results were compared with the literature densities. In particular, the trend of density versus temperature for a constant mass of sample observed experimentally differs from the trend calculated by the equation provided by the International Association for Properties of Water and Steam (IAPWS-95) outside the range of validity, i.e., in the metastable region.
Detecting divertor damage during steady state operation of Wendelstein 7-X from thermographic measurements
Authors: Rodatos A. , Greuner H. , Jakubowski M. W. , Boscary J. , Wurden G. A. , Pedersen T. S. , König R.
Published: February 2016

Wendelstein 7-X (W7-X) aims to demonstrate the reactor capability of the stellarator concept, by creating plasmas with pulse lengths of up to 30 min at a heating power of up to 10 MW. The divertor plasma facing components will see convective steady state heat flux densities of up to 10 MW/m2. These high heat flux target elements are actively cooled and are covered with carbon fibre reinforced carbon (CFC) as plasma facing material. The CFC is bonded to the CuCrZr cooling structure. Over the life time of the experiment this interface may weaken and cracks can occur, greatly reducing the heat conduction between the CFC tile and the cooling structure. Therefore, there is not only the need to monitor the divertor to prevent damage by overheating but also the need to detect these fatigue failures of the interface. A method is presented for an early detection of fatigue failures of the interface layer, solely by using the information delivered by the IR-cameras monitoring the divertor. This was developed and validated through experiments made with high heat flux target elements prior to installation in W7-X.
Design and test of a broadband split-and-delay unit for attosecond XUV-XUV pump-probe experiments
Authors: Campi F. , Coudert-Alteirac H. , Miranda M. , Rading L. , Manschwetus B. , Rudawski P. , L’Huillier A. , Johnsson P.
Published: February 2016

We present the design of a split-and-delay unit for the production of two delayed replicas of an incident extreme ultraviolet (XUV) pulse. The device features a single grazing incidence reflection in combination with attenuation of remaining infrared light co-propagating with the XUV beam, offering a high throughput without the need of introducing additional optics that would further decrease the XUV flux. To achieve the required spatial and temporal stabilities, the device is controlled by two PID-controllers monitoring the delay and the beam pointing using an optical reference laser beam, making collimation of the beam by additional optics unnecessary. Finally, we demonstrate the stability of the split-and-delay unit by performing all-reflective autocorrelation measurements on broadband few-cycle laser pulses.
A biomimetic tactile sensing system based on polyvinylidene fluoride film
Authors: Xin Yi , Tian Hongying , Guo Chao , Li Xiang , Sun Hongshuai , Wang Peiyuan , Qian Chenghui , Wang Shuhong , Wang Cheng
Published: February 2016

Polyvinylidene fluoride (PVDF) film has been widely investigated as a sensing material due to its outstanding properties such as biocompatibility, high thermal stability, good chemical resistance, high piezo-, pyro- and ferro-electric properties. This paper reports on the design, test, and analysis of a biomimetic tactile sensor based on PVDF film. This sensor consists of a PVDF film with aluminum electrodes, a pair of insulating layers, and a “handprint” friction layer with a copper foil. It is designed for easy fabrication and high reliability in outputting signals. In bionics, the fingerprint of the glabrous skin plays an important role during object handling. Therefore, in order to enhance friction and to provide better manipulation, the ridges of the fingertips were introduced into the design of the proposed tactile sensor. And, a basic experimental study on the selection of the high sensitivity fingerprint type for the biomimetic sensor was performed. In addition, we proposed a texture distinguish experiment to verify the sensor sensitivity. The experiment’s results show that the novel biomimetic sensor is effective in discriminating object surface characteristics. Furthermore, an efficient visual application program (LabVIEW) and a quantitative evaluation method were proposed for the verification of the biomimetic sensor. The proposed tactile sensor shows great potential for contact force and slip measurements.
An innovative spraying setup to obtain uniform salt(s) mixture deposition to investigate hot corrosion
Authors: Mannava Venkateswararao , Swaminathan A. Vignesh , Kamaraj M. , Kottada Ravi Sankar
Published: February 2016

A hot corrosion study via molten salt deposition and its interaction with creep/fatigue play a critical role in predicting the life of gas turbine engine components. To do systematic hot corrosion studies, deposition of molten salts on specimens should be uniform with good adherence. Thus, the present study describes an in-house developed spraying setup that produces uniform and reliable molten salt deposition in a repeatable fashion. The efficacy of the present method was illustrated by depositing 90 wt. % Na2SO4 + 5 wt. % NaCl + 5 wt. % NaV O3 salt mixture on hot corrosion coupons and on creep specimens, and also by comparing with other deposition methods.
A 500 A device characterizer utilizing a pulsed-linear amplifier
Authors: Lacouture Shelby , Bayne Stephen
Published: February 2016

With the advent of modern power semiconductor switching elements, the envelope defining “high power” is an ever increasing quantity. Characterization of these semiconductor power devices generally falls into two categories: switching, or transient characteristics, and static, or DC characteristics. With the increasing native voltage and current levels that modern power devices are capable of handling, characterization equipment meant to extract quasi-static IV curves has not kept pace, often leaving researchers with no other option than to construct ad hoc curve tracers from disparate pieces of equipment. In this paper, a dedicated 10 V, 500 A curve tracer was designed and constructed for use with state of the art high power semiconductor switching and control elements. The characterizer is a physically small, pulsed power system at the heart of which is a relatively high power linear amplifier operating in a switched manner in order to deliver well defined square voltage pulses. These actively shaped pulses are used to obtain device’s quasi-static DC characteristics accurately without causing any damage to the device tested. Voltage and current waveforms from each pulse are recorded simultaneously by two separate high-speed analog to digital converters and averaged over a specified interval to obtain points in the reconstructed IV graph.
Acoustic focusing by symmetrical self-bending beams with phase modulations
Authors: Gao He , Gu Zhong-ming , Liang Bin , Zou Xin-ye , Yang Jing , Yang Jun , Cheng Jian-chun
Published: February 2016

We propose a scheme for generating high-efficient acoustic focusing capable of circumventing obstacles in the propagating medium. This distinct feature that is highly desirable for practical applications is realized by employing two symmetrical Airy beams, and a different type of acoustic lens is designed by using a zero-index medium to provide the required phase profile with extremely high resolution. Furthermore, the scheme has the flexibility of generating tunable focal length. We anticipate our design to open possibilities for the design of acoustic lens and have potential applications in various important scenarios such as biomedical imaging/therapy and non-destructive evaluation.
Elastocaloric effect in Ti-Ni shape-memory wires associated with the B2 ↔ B19' and B2 ↔ R structural transitions
Authors: Soto-Parra Daniel , Vives Eduard , Mañosa Lluís , Matutes-Aquino J. A. , Flores-Zúñiga Horacio , Planes Antoni
Published: February 2016

We have studied the elastocaloric properties of Ti-Ni shape-memory wires subjected to specific heat treatments to decouple the B2 ↔ R transition from the B2 ↔ B19' one. The entropy values at moderate stresses (∼170 MPa) for the B2 ↔ B19' transition are remarkably high (in the range 60–80 J/kg K). However, in spite of the B2 ↔ R transition exhibits significantly lower entropy changes (∼12 J/kg K), the much smaller hysteresis of this transition gives rise to a larger reversible elastocaloric effect for low applied stresses. Therefore, the reversible elastocaloric strength associated with the B2 ↔ R is larger than the elastocaloric strength associated with the B2 ↔ B19' transition.
Three-dimensional interaction force and tunneling current spectroscopy of point defects on rutile TiO2(110)
Authors: Baykara Mehmet Z. , Mönig Harry , Schwendemann Todd C. , Ünverdi Özhan , Altman Eric I. , Schwarz Udo D.
Published: February 2016

The extent to which point defects affect the local chemical reactivity and electronic properties of an oxide surface was evaluated with picometer resolution in all three spatial dimensions using simultaneous atomic force/scanning tunneling microscopy measurements performed on the (110) face of rutile TiO2. Oxygen atoms were imaged as protrusions in both data channels, corresponding to a rarely observed imaging mode for this prototypical metal oxide surface. Three-dimensional spectroscopy of interaction forces and tunneling currents was performed on individual surface and subsurface defects as a function of tip-sample distance. An interstitial defect assigned to a subsurface hydrogen atom is found to have a distinct effect on the local density of electronic states on the surface, but no detectable influence on the tip-sample interaction force. Meanwhile, spectroscopic data acquired on an oxygen vacancy highlight the role of the probe tip in chemical reactivity measurements.
Efficient use of coherent X-rays in ptychography: Towards high-resolution and high-throughput observation of weak-phase objects
Authors: Burdet Nicolas , Shimomura Kei , Hirose Makoto , Suzuki Akihiro , Takahashi Yukio
Published: February 2016

The efficient use of coherent X-rays is a crucial issue for ptychography at synchrotron facilities. We propose a method for optimizing the population of coherent modes for an optimal resolution. We show by a wave optical simulation that the intensity of a nearly diffraction-limited focusing X-ray beam can be described as an incoherent sum of a few orthogonal modes and that the first-mode flux significantly increases within a secondary source size by relaxing the requirement on the degree of coherence. We experimentally demonstrate it by means of multiple-mode ptychography with a synchrotron X-ray and achieve the high-resolution imaging of a weak-phase object. The present approach enables the high-resolution and high-throughput observation of weak-phase objects in materials science and biology.
Electrical conduction mechanisms in PbSe and PbS nano crystals 3D matrix layer
Authors: Arbell Matan , Hechster Elad , Sarusi Gabby
Published: February 2016

A simulation study and measurements of the electrical conductance in a PbSe and PbS spherical Nano-crystal 3D matrix layer was carried out focusing on its dependences of Nano-crystal size distribution and size gradient along the layer thickness (z-direction). The study suggests a new concept of conductance enhancement by utilizing a size gradient along the layer thickness from mono-layer to the next mono-layer of the Nano-crystals, in order to create a gradient of the energy levels and thus improve directional conductance in this direction. A Monte Carlo simulation of the charge carriers path along the layer thickness of the Nano-crystals 3D matrix using the Miller-Abrahams hopping model was performed. We then compared the conductance characteristics of the gradual size 3D matrix layer to a constant-sized 3D matrix layer that was used as a reference in the simulation. The numerical calculations provided us with insights into the actual conductance mechanism of the PbSe and PbS Nano-crystals 3D matrix and explained the discrepancies in actual conductance and the variability in measured mobilities published in the literature. It is found that the mobility and thus conductance are dependent on a critical electrical field generated between two adjacent nano-crystals. Our model explains the conductance dependents on the: Cathode-Anode distance, the distance between the adjacent nano-crystals in the 3D matrix layer and the size distribution along the current direction. Part of the model (current-voltage dependence) was validated using a current-voltage measurements taken on a constant size normal distribution nano-crystals PbS layer (330nm thick) compared with the predicted I-V curves. It is shown that under a threshold bias, the current is very low, while after above a threshold bias the conductance is significantly increased due to increase of hopping probability. Once reaching the maximum probability the current tend to level-off reaching the maximal conductance available through the sequential hopping and nano crystals based layer behaves as a resistor under bias.
Microstructured gradient-index lenses for THz photoconductive antennas
Authors: Brincker Mads , Karlsen Peter , Skovsen Esben , Søndergaard Thomas
Published: February 2016

A new type of substrate lens for photoconductive antennas (PCA’s) based on sub-wavelength microstructuring is presented and studied theoretically by the use of Greens function integral equation methods (GFIEM’s). By etching sub-wavelength trenches into a flat substrate, the effective dielectric constant can be designed to function like a gradient index (GRIN) lens. The proposed GRIN substrate lenses have sub-mm dimension, which is smaller than the dimensions of a typical hyper-hemispherical substrate lens (HSL), and could enable fabrication of arrays of closely packed PCA’s with individual lenses integrated directly into the PCA substrate. The performance of different GRIN lenses is compared to a HSL and shown to be comparable with regards to the terahertz radiation extraction efficiency, and it is shown that the collimating properties of these GRIN lenses can be tailored by changing the parameters used for microstructuring.
Ultrafast responses of dipolar and V-shaped dipicolinate derivatives with potential applications in the labeling of biomolecules
Authors: Wang Yaochuan , Liu Siyuan , Liu Dajun , Wang Guiqiu , Xiao Haibo
Published: February 2016

A dipolar dipicolinate derivative, trans-dimethyl-4-[4′-(N,N-diphenylamino)-styry1]-pyridin-2,6-dicarboxylate (P-1), and a P-1based V-shaped compound, {4-[(E)-2-(2,6-dimethoxycarbonylpyridin-4-yl) vinyl]}-N-phenyl-N-{4-[(E)-2-(2,6-dimethoxycarbonylpyridin-4-yl)vinylphenyl]}aniline (P-2), with intense two-photon fluorescence emission properties were systematically investigated by using steady-state absorption and fluorescence spectroscopy, open-aperture Z-scans, and two-photon excited fluorescence (TPF). The two-photon absorption cross-section of the V-shaped compound P-2 in tetrahydrofuran (THF) was determined to be 208 GM, which represents a 6.5-fold enhancement compared with its dipolar counterpart P-1 (32 GM). Extension of the intramolecular charge transfer (ICT) in the V-shaped dipicolinate derivative has been suggested as the mechanism of enhancement. The excited state dynamics from transient absorption spectroscopy were analyzed and discussed. The formation and relaxation lifetimes of the ICT state for these dipicolinate derivatives in THF solutions were found to be several picoseconds and several hundred picoseconds, respectively. The results show an increased ICT character of the V-shaped compound and a potential application for this compound in two-photon fluorescence imaging fields.
Fluoroquinolone interactions with
Mycobacterium tuberculosis
gyrase: Enhancing drug activity against wild-type and resistant gyrase
Authors: Aldred Katie J. , Blower Tim R. , Kerns Robert J. , Berger James M. , Osheroff Neil
Published: February 2016

Significance

Moxifloxacin and other fluoroquinolone antibacterial agents are important antituberculosis therapeutic agents. Fluoroquinolones kill
Mycobacterium tuberculosis
, the causative agent of tuberculosis, by increasing levels of DNA breaks generated by gyrase, an essential type II topoisomerase that regulates DNA topology. As fluoroquinolone use in antituberculosis regimens is becoming more pronounced, understanding the basis of drug–gyrase interactions and resistance is becoming more important. By using a mechanism-based chemical biology approach, our work identified critical drug features that mediate fluoroquinolone interactions with
M. tuberculosis
gyrase and determined the biochemical basis for fluoroquinolone resistance caused by the most common clinical mutations in gyrase. These findings allowed us to identify a moxifloxacin derivative that displays enhanced activity against WT gyrase and maintains high activity against clinically relevant resistant enzymes.
Stress associated changes in Pavlovian-instrumental transfer in humans
Authors: Quail Stephanie L. , Morris Richard W. , Balleine Bernard W.
Published: February 2016

Predictive learning is known to influence instrumental responding for reward. Cues associated with an instrumental outcome can influence performance in two ways: (a) by selectively promoting actions associated with the outcome predicted by the cue (specific transfer), and (b) by increasing motivation and the vigour of instrumental responding (general transfer). To examine these two distinct processes in humans we developed a novel behavioural task in which participants were able to liberate junk-food snacks from a virtual vending machine. Additionally, the relationship between stress and cue-driven reward seeking was examined using participant scores on the Depression Anxiety and Stress Scale (DASS). Reward-paired cues were found to separately bias action selection and influence the rate of responding for rewards. Furthermore, the effects of reward-paired cues on the rate of responding for reward was influenced by increased stress and anxiety. Increased levels of stress and anxiety were associated particularly with changes in cue-driven response vigour; whereas high levels of stress and anxiety were associated with elevated responding above baseline in the presence of a cue associated with a non-rewarding outcome, participants with low levels of anxiety and stress showed appropriate suppression of responding during this cue. These differences in performance between high and low anxiety and stress participants provides initial evidence that, as has been demonstrated in rodents, stress affects the influence of cue-driven response vigour in humans.
Antibodies against a secreted product of Staphylococcus aureus trigger phagocytic killing
Authors: Thomer Lena , Emolo Carla , Thammavongsa Vilasack , Kim Hwan Keun , McAdow Molly E. , Yu Wenqi , Kieffer Matthew , Schneewind Olaf , Missiakas Dominique
Published: February 2016

Host immunity against bacteria typically involves antibodies that recognize the microbial surface and promote phagocytic killing. Methicillin-resistant Staphylococcus aureus (MRSA) is a frequent cause of lethal bloodstream infection; however, vaccines and antibody therapeutics targeting staphylococcal surface molecules have thus far failed to achieve clinical efficacy. S. aureus secretes coagulase (Coa), which activates host prothrombin and generates fibrin fibrils that protect the pathogen against phagocytosis by immune cells. Because of negative selection, the coding sequence for the prothrombin-binding D1-D2 domain is highly variable and does not elicit cross-protective immune responses. The R domain, tandem repeats of a 27-residue peptide that bind fibrinogen, is conserved at the C terminus of all Coa molecules, but its functional significance is not known. We show here that the R domain enables bloodstream infections by directing fibrinogen to the staphylococcal surface, generating a protective fibrin shield that inhibits phagocytosis. The fibrin shield can be marked with R-specific antibodies, which trigger phagocytic killing of staphylococci and protect mice against lethal bloodstream infections caused by a broad spectrum of MRSA isolates. These findings emphasize the critical role of coagulase in staphylococcal escape from opsonophagocytic killing and as a protective antigen for S. aureus vaccines.
SweepFinder2: increased sensitivity, robustness and flexibility
Authors: DeGiorgio Michael , Huber Christian D. , Hubisz Melissa J. , Hellmann Ines , Nielsen Rasmus
Published: February 2016

Summary: SweepFinder is a widely used program that implements a powerful likelihood-based method for detecting recent positive selection, or selective sweeps. Here, we present SweepFinder2, an extension of SweepFinder with increased sensitivity and robustness to the confounding effects of mutation rate variation and background selection. Moreover, SweepFinder2 has increased flexibility that enables the user to specify test sites, set the distance between test sites and utilize a recombination map.

Availability and implementation: SweepFinder2 is a freely-available (www.personal.psu.edu/mxd60/sf2.html) software package that is written in C and can be run from a Unix command line.

Contact:  mxd60@psu.edu