bluuebunny/crossref_metadata_2025 huggingface dataset:
Neuroglobin, a pro-survival player in estrogen receptor α-positive cancer cells
Authors: Fiocchetti M , Nuzzo M T , Totta P , Acconcia F , Ascenzi P , Marino M
Published: October 2014

Recently, we reported that human neuroglobin (NGB) is a new player in the signal transduction pathways that lead to 17β-estradiol (E2)-induced neuron survival. Indeed, E2 induces in neuron mitochondria the enhancement of NGB level, which in turn impairs the activation of a pro-apoptotic cascade. Nowadays, the existence of a similar pathway activated by E2 in non-neuronal cells is completely unknown. Here, the role of E2-induced NGB upregulation in tumor cells is reported. E2 induced the upregulation of NGB in a dose- and time-dependent manner in MCF-7, HepG2, SK-N-BE, and HeLa cells transfected with estrogen receptor α (ERα), whereas E2 was unable to modulate the NGB expression in the ERα-devoid HeLa cells. Both transcriptional and extranuclear ERα signals were required for the E2-dependent upregulation of NGB in MCF-7 and HepG2 cell lines. E2 stimulation modified NGB intracellular localization, inducing a significant reduction of NGB in the nucleus with a parallel increase of NGB in the mitochondria in both HepG2 and MCF-7 cells. Remarkably, E2 pretreatment did not counteract the H2O2-induced caspase-3 and poly (ADP-ribose) polymerase 1 (PARP-1) cleavage, as well as Bcl-2 overexpression in MCF-7 and HepG2 cells in which NGB was stably silenced by using shRNA lentiviral particles, highlighting the pivotal role of NGB in E2-induced antiapoptotic pathways in cancer cells. Present results indicate that the E2-induced NGB upregulation in cancer cells could represent a defense mechanism of E2-related cancers rendering them insensitive to oxidative stress. As a whole, these data open new avenues to develop therapeutic strategies against E2-related cancers.
Nonconventional chemical inhibitors of microRNA: therapeutic scope
Authors: Jayaraj Gopal Gunanathan , Nahar Smita , Maiti Souvik
Published: October 2014

MicroRNAs (miRNAs) are a class of genomically encoded small RNA molecules (∼22nts in length), which regulate gene expression post transcriptionally. miRNAs are implicated in several diseases, thus modulation of miRNA is of prime importance. Small molecules offer a non-conventional alternative to do so.
Diastereoselective synthesis of α-(aminomethyl)-γ-butyrolactones via a catalyst-free aminolactonization
Authors: Ramachandran P. Veeraraghavan , Nicponski Daniel R.
Published: October 2014

An auto-catalytic domino reaction involving an aza-Michael reaction, proton transfer, and lactonization furnishing α-aminomethyl-γ-butyrolactones in near quantitative yields and excellent diastereoselectivity is described.
Organic mixed valency in quadruple hydrogen-bonded triarylamine dimers bearing ureido pyrimidinedione moieties
Authors: Tahara Keishiro , Nakakita Tetsufumi , Katao Shohei , Kikuchi Jun-ichi
Published: October 2014

This study represents the first example of proton-coupled “organic” mixed valency in solution with different substituents being used to control the stability.
Molecular structure and polymorphism of a cyclohexanediol: trans-1,4-cyclohexanedimethanol
Authors: Rosado Mário T. S. , Maria Teresa M. R. , Castro Ricardo A. E. , Canotilho João , Silva Manuela Ramos , Eusébio M. Ermelinda S.
Published: October 2014

The methoxy substituent intrans-1,4-cyclohexanedimethanol stabilizes equatorial conformations, whose two polymorphs were found and characterized by DSC, FTIR, and XRD.
Influence of the cation size on the second harmonic generation response of chiral A(VO2)2(PO4)·3H2O (A = K+, NH4+ and Rb+)
Authors: Gautier R. , Auguste S. , Clevers S. , Dupray V. , Coquerel G. , Le Fur E.
Published: October 2014

Second harmonic generation responses of new chiral vanadium phosphate materials were shown to strongly increase upon contraction of the structure.
Six-dimensional quantum dynamics for dissociative chemisorption of H2and D2on Ag(111) on a permutation invariant potential energy surface
Authors: Jiang Bin , Guo Hua
Published: October 2014

Quantum dynamics on a permutation invariant potential energy surface for H2dissociation on Ag(111) yield satisfactory agreement with experiment.
Efficient and recyclable heterogeneous zinc alkyl carboxylate catalyst for the synthesis of N-phenyl carbamate from aniline and dimethylcarbonate
Authors: Wang Yi , Liu Bo
Published: October 2014

A heterogeneous salt catalyst with zinc alkyl carboxylate chemically bonded on silica was highly active and recyclable in the synthesis of MPC.
Synthesis of discrete Re(i) di- and tricarbonyl assemblies using a [4 × 1] directional bonding strategy
Authors: Laramée-Milette Baptiste , Lachance-Brais Christophe , Hanan Garry S.
Published: October 2014

Discrete assembly of two Re(i) squares was achieved by a simple [4 × 1] strategy where the complexes, [Re(4-pytpy-κ2N)(CO)3Br] and [Re(4-pytpy-κ3N)(CO)2Br], act as their own ligands. The properties of the assemblies and their precursors are described along with solid-state X-ray diffraction studies.
Heterogeneously catalyzed strategies for the deconstruction of high density polyethylene: plastic waste valorisation to fuels
Authors: Burange Anand S. , Gawande Manoj B. , Lam Frank L. Y. , Jayaram Radha V. , Luque Rafael
Published: October 2014

Waste to energy: catalytic degradation of plastic waste can provide valuable energy carriers.
Elemental and molecular mass spectrometry for integrated selenosugar speciation in liver and kidney tissues of maternal feeding and supplemented rats
Authors: González-Iglesias Héctor , Fernández-Sánchez María Luisa , Lu Ying , Fernández Menéndez Sonia , Pergantis Spiros A. , Sanz-Medel Alfredo
Published: October 2014

The integrated use of elemental and molecular ion sources for enhanced selenium speciation data in rat liver and kidneys, along with its potential for Se-supplement studies are highlighted.
Advanced thermo-mechanical characterization of organic materials by piezoresistive organic resonators
Authors: Thuau D. , Ayela C. , Lemaire E. , Heinrich S. , Poulin P. , Dufour I.
Published: October 2014

Rapid, low-cost and accurate characterization of the viscoelastic properties of organic materials using piezoresistive MEMS resonators.
On the properties of S⋯O and S⋯π noncovalent interactions: the analysis of geometry, interaction energy and electron density
Authors: Zhou Fangfang , Liu Ruirui , Li Ping , Zhang Houyu
Published: October 2014

We report computational studies on the origin and magnitude of non-covalent S⋯O and S⋯π interactions.
High-resolution characterization of the diffusion of light chemical elements in metallic components by scanning microwave microscopy
Authors: Optasanu Virgil , Bourillot Eric , Vitry Pauline , Plassard Cédric , Beaurenaut Laure , Jacquinot Pierre , Herbst Frédéric , Berger Pascal , Lesniewska Eric , Montessin Tony
Published: October 2014

An original sub-surface, high spatial resolution tomographic technique based on scanning microwave microscopy (SMM) is used to visualize in-depth materials with different chemical compositions.
Li1.2Mn0.6Ni0.1Co0.1O2 microspheres constructed by hierarchically arranged nanoparticles as lithium battery cathode with enhanced electrochemical performance
Authors: Remith P. , Kalaiselvi N.
Published: October 2014

Novel Li1.2Mn0.6Ni0.1Co0.1O2 hollow microspheres, formed out of the hierarchically arranged nanocrystalline particles containing rhombohedral and monoclinic phases exhibit synergistically improved capacity of 242 mA h g−1 with 97% coulombic efficiency.
Tuning of the near-infrared localized surface plasmon resonance of Cu2−xSe nanoparticles with lysozyme-induced selective aggregation
Authors: Lie Shao Qing , Zou Hong Yan , Chang Yong , Huang Cheng Zhi
Published: October 2014

Poly(styrene sulfonic acid)sodium stabilized Cu2−xSe nanoparticles (PSS–Cu2−xSe NPs) with localized surface plasmon resonance (LSPR) absorption centered at 980 nm can be selectively aggregated by lysozyme (Lys) through the electrostatic attraction, giving rise to a red shift of the LSPR in the near-infrared (NIR) region.
Correlation of selected molecular properties and recovery values in volatile organic compounds analysis: comparison of two water matrices
Authors: Ivančev-Tumbas Ivana , Sekulić Tatjana-Djaković , Molnar Jelena , Tubić Aleksandra , Agbaba Jasmina , Tričković Jelena , Kragulj Marijana
Published: October 2014

This study investigates if certain molecular properties can influence the recovery of 18 volatile organic compounds (VOCs) in water under the applied analytical conditions, a P&T GC method with MS detection.
Theoretical study on molecular packing and electronic structure of bi-1,3,4-oxadiazole derivatives
Authors: Wang Haitao , Bai Fu-Quan , Jia Xiaoshi , Cao Di , Mahesh Kumar Ravva , Brédas Jean-Luc , Qu Songnan , Bai Binglian , Zhang Hong-Xing , Li Min
Published: October 2014

One of the energy-minimum structures predicted by the intermolecular interaction potential energy surface computed using the M062x/6-31G** method closely resembled the crystal packing.
Recyclable Bi2WO6-nanoparticle mediated one-pot multicomponent reactions in aqueous medium at room temperature
Authors: Paplal Banoth , Nagaraju S. , Veerabhadraiah Palakollu , Sujatha Kodam , Kanvah Sriram , Vijaya Kumar B. , Kashinath Dhurke
Published: October 2014

Room temperature multicomponent reactions (MCRs) are reported using Bi2O3, BiVO4, and Bi2WO6 (nanoparticle) as heterogeneous catalysts. Among these, Bi2WO6 (5 mol%) nanoparticles showed excellent reactivity for the synthesis of functionalized dihydropyridine, polyhydroquinoline, 4H-chromene and 2-amino-4H-benzo[b]pyran derivatives in aqueous medium.
Batch and continuous phosphate uptake studies employing a ferrimagnetic calcium silicate hydrate composite
Authors: Cairns Mathew J. , Borrmann Thomas
Published: October 2014

Composite particles of ferrimagnetic magnetite and a nano-structured calcium silicate hydrate were used for the sorption of phosphate. The composite absorbed up to 5.5 mmol phosphate per gram and settled within minutes compared to hours for the pure sorbent.
Extension of high-order harmonic generation cutoff via control of chirped laser pulses in the vicinity of metal nanostructure media
Authors: Hekmatara S. H. , Mohebbi M. , Rahpeyma J.
Published: October 2014

By using a suitable chirping field, an ultrashort pulse was obtained in the vicinity of the metal nanostructure.
Ab initio calculations of quantum transport of Au–GaN–Au nanoscale junctions
Authors: Zhang Tian , Cheng Yan , Chen Xiang-Rong
Published: October 2014

We investigate the contact geometry and electronic transport properties of a GaN pair sandwiched between Au electrodes by performing density functional theory plus the non-equilibrium Green's function method.
Oxygen-enriched activated carbons from pomelo peel in high energy density supercapacitors
Authors: Peng Chao , Lang Junwei , Xu Shan , Wang Xiaolai
Published: October 2014

Pomelo peel as biomass-derived porous activated carbon is used for the preparation of a high energy density symmetric supercapacitor.
Benzylamine as an arylcarboxy surrogate: a copper catalysed o-benzoxylation of 2-phenylpyridines using benzyl amines
Authors: Behera Ahalya , Rout Saroj K. , Guin Srimanta , Patel Bhisma K.
Published: October 2014

Different reactivities and selectivities of Cu and Pd catalysts have been demonstrated in the reactions of benzylamines with 2-phenylpyridines.
Smart functional polymers – a new route towards creating a sustainable environment
Authors: Ganesh V. Anand , Baji Avinash , Ramakrishna Seeram
Published: October 2014

Smart functional polymers have gained a huge amount of interest in recent times due to their innumerable applications in areas including sensors, actuators, switchable wettability, bio-medical and environmental applications.
Fabrication of NiTe films by transformed electrodeposited Te thin films on Ni foils and their electrical properties
Authors: Mu Yannan , Li Qian , Lv Pin , Chen Yanli , Ding Dong , Su Shi , Zhou Liying , Fu Wuyou , Yang Haibin
Published: October 2014

Tellurium (Te) source of compact nickel telluride (NiTe) thin film was prepared by simple electrochemical deposition method.
Novel artificial metalloenzymes by in vivo incorporation of metal-binding unnatural amino acids
Authors: Drienovská Ivana , Rioz-Martínez Ana , Draksharapu Apparao , Roelfes Gerard
Published: October 2014

Artificial metalloenzymes for asymmetric catalysis were created by in vivo incorporation of unnatural metal binding amino acids into LmrR.
Stoichiometric to catalytic reactivity of the aryl cycloaurated species with arylboronic acids: insight into the mechanism of gold-catalyzed oxidative C(sp2)–H arylation
Authors: Wu Qian , Du Chenglong , Huang Yumin , Liu Xingyan , Long Zhen , Song Feijie , You Jingsong
Published: October 2014

The aryl cycloaurated species are established as reliable models for understanding the gold(iii)-catalyzed oxidative cross-couplings between arenes and arylboronic acids.
Kinetically selective inhibitors of histone deacetylase 2 (HDAC2) as cognition enhancers
Authors: Wagner F. F. , Zhang Y.-L. , Fass D. M. , Joseph N. , Gale J. P. , Weïwer M. , McCarren P. , Fisher S. L. , Kaya T. , Zhao W.-N. , Reis S. A. , Hennig K. M. , Thomas M. , Lemercier B. C. , Lewis M. C. , Guan J. S. , Moyer M. P. , Scolnick E. , Haggarty S. J. , Tsai L.-H. , Holson E. B.
Published: October 2014

Kinetically selective inhibitors of HDAC2 enhanced learning and memory in a CK-p25 mouse model of neurodegeneration.
Modification by covalent reaction or oxidation of cysteine residues in the tandem-SH2 domains of ZAP-70 and Syk can block phosphopeptide binding
Authors: Visperas Patrick R. , Winger Jonathan A. , Horton Timothy M. , Shah Neel H. , Aum Diane J. , Tao Alyssa , Barros Tiago , Yan Qingrong , Wilson Christopher G. , Arkin Michelle R. , Weiss Arthur , Kuriyan John
Published: October 2014

Zeta-chain associated protein of 70 kDa (ZAP-70) and spleen tyrosine kinase (Syk) are non-receptor tyrosine kinases that are essential for T-cell and B-cell antigen receptor signalling respectively. They are recruited, via their tandem-SH2 (Src-homology domain 2) domains, to doubly phosphorylated immunoreceptor tyrosine-based activation motifs (ITAMs) on invariant chains of immune antigen receptors. Because of their critical roles in immune signalling, ZAP-70 and Syk are targets for the development of drugs for autoimmune diseases. We show that three thiol-reactive small molecules can prevent the tandem-SH2 domains of ZAP-70 and Syk from binding to phosphorylated ITAMs. We identify a specific cysteine residue in the phosphotyrosine-binding pocket of each protein (Cys39 in ZAP-70, Cys206 in Syk) that is necessary for inhibition by two of these compounds. We also find that ITAM binding to ZAP-70 and Syk is sensitive to the presence of H2O2 and these two cysteine residues are also necessary for inhibition by H2O2. Our findings suggest a mechanism by which the reactive oxygen species generated during responses to antigen could attenuate signalling through these kinases and may also inform the development of ZAP-70 and Syk inhibitors that bind covalently to their SH2 domains.
Discovery and characterization of a novel extremely acidic bacterial N-glycanase with combined advantages of PNGase F and A
Authors: Wang Ting , Cai Zhi P. , Gu Xiao Q. , Ma Hong Y. , Du Ya M. , Huang Kun , Voglmeir Josef , Liu Li
Published: October 2014

Peptide-N4-(N-acetyl-β-glucosaminyl) asparagine amidases [PNGases (peptide N-glycosidases), N-glycanases, EC 3.5.1.52] are essential tools in the release of N-glycans from glycoproteins. We hereby report the discovery and characterization of a novel bacterial N-glycanase from Terriglobus roseus with an extremely low pH optimum of 2.6, and annotated it therefore as PNGase H+. The gene of PNGase H+ was cloned and the recombinant protein was successfully expressed in Escherichia coli. The recombinant PNGase H+ could liberate high mannose-, hybrid- and complex-type N-glycans including core α1,3-fucosylated oligosaccharides from both glycoproteins and glycopeptides. In addition, PNGase H+ exhibited better release efficiency over N-glycans without core α1,3-fucose compared with PNGase A. The facile expression, non-glycosylated nature, unusual pH optimum and broad substrate specificity of this novel type of N-glycanase makes recombinant PNGase H+ a versatile tool in N-glycan analysis.
Model‐based temperature control of a selective catalytic reduction system
Authors: Tayamon Soma , Larsson Anders , Westerberg Björn
Published: October 2014

Selective catalytic reduction (SCR) systems are commonly used for exhaust gas aftertreatment in many applications. For optimal NOx reduction using the SCR technique a certain temperature must be reached. This study deals with modelling and control of the temperature inside the SCR system for optimal catalyst operation. A first principle‐based model is described for the propagation of the temperature inside the catalyst. The model is described in linear parameter varying (LPV) state‐space form and used for control of the temperature using a linear‐quadratic‐Gaussian (LQG) controller. Necessary conditions for obtaining an optimal controller without complete state information are defined. This leads to a discrete‐time LQG controller for LPV systems. The results obtained for the controller are based on several assumptions to ensure the stability of the controller. The states of the proposed model are not measurable. For this purpose, a Kalman filter‐based observer is designed for estimation of the states that are used for state feedback in the controller. The observer is designed for discrete‐time LPV systems and necessary assumptions for the observer are derived in the work. The resulting model of the temperature gives a model fit of up to 77% for validation data and the controller requirements are met using the proposed controller applied in a simulator environment.
Data‐based two‐degree‐of‐freedom iterative control approach to constrained non‐linear systems
Authors: Radac Mircea‐Bogdan , Precup Radu‐Emil
Published: October 2014

This study proposes a data‐based model‐free approach to reference trajectory tracking in two‐degree‐of‐freedom non‐linear control system (CS) structures. This model‐free control approach tunes both the feedback controller parameters and the reference input sequence accounting for control saturation and control rate constraints. The controller is iteratively tuned in a non‐linear framework that employs a gradient descent search approach. The model‐free gradient estimates are obtained by a perturbation‐based approach. The reference input tuning is carried out in a linear framework using an iterative learning control‐based approach, and it also includes a model‐free gradient search algorithm where the gradient estimates are obtained by a similar perturbation‐based approach. The number of real‐world experiments is significantly reduced by the use of simulated models identified as neural networks. A digitally simulated case study concerning the angular position control of a non‐linear aerodynamic twin‐rotor system shows that the author's approach can effectively improve the CS performance.
Gaussian mixture regression and local linear network model for data‐driven estimation of air mass
Authors: Kolewe Bjoern , Haghani Adel , Beckmann Robert , Jeinsch Torsten
Published: October 2014

The conventional approaches for modelling of charge cycle in combustion engines are based on first principles. In this approaches, it is necessary to estimate different parameters in engine, which is very difficult to implement in real‐time. In addition, it requires a high parameterisation effort because of a variety of engine characteristics. The model is further used in engine control unit to improve the efficiency of the combustion. Moreover, it can be used for estimation of some physical variables in engine to increase the performance of the controller. It also avoids the installation of extra sensors and reduces the costs of production. In this study, two different data‐driven modelling methods for estimation of air mass are investigated. They also offer a flexible modelling approach considering various options for equipment as well as sensors and actuators in the engines. Both data‐driven methods, the Gaussian mixture regression (GMR) and the local linear model tree (LOLIMOT) algorithm, allow a flexible modelling with a high input space dimensionality, with sparsity of data, a good interpretability and also offer possibilities of adaptation and local optimisation. While the GMR uses a statistical approaches to train the model, in the LOLIMOT an incremental, heuristic approach is used. Both methods are applied to the data obtained from a spark‐ignition engine and the results are compared and discussed.
Synthesis of low‐coefficient sensitivity controllers with respect to multiplicative controller coefficient variations
Authors: Guo Xiang‐Gui , Gao Qiang , Xu Zhe
Published: October 2014

In this study, a set of optimal state‐space descriptions with minimum H∞ ‐sensitivity to multiplicative controller coefficient variations and a desirable disturbance attenuation level is synthesised for discrete‐time linear systems. The first aim is to present a new strategy to evaluate the H∞ ‐sensitivity of the transfer function to multiplicative controller coefficient variations. The H∞ norm of the sum of coefficient sensitivity functions is regarded as an H∞ ‐sensitivity measure. The second contribution is to present less conservative conditions to design low‐sensitivity controllers via minimisation of the H∞ ‐sensitivity measure. In addition, a linear matrix inequality‐based algorithm is developed to obtain the controller gain matrices. Finally, two numerical examples which demonstrate the effectiveness and advantages of the proposed method are presented.
Content‐based image retrieval in dermatology using intelligent technique
Authors: Jiji Gnanasigamony Wiselin , Durai Raj Peter Savariraj Johnson
Published: October 2014

This study proposes a content‐based image retrieval system for skin lesion images as a diagnostic aid. Effectiveness is measured by the rate of correct retrieval of images from skin lesions. The proposed architecture is used to retrieve digital images and the name of the disease category from an image data repository by the contents in the image, such as shape, texture and colour that is extracted from the image. The author's proposed algorithm used feature vector, classification and regression tree to retrieve comprehensive reference sources for diagnostic purpose. The results proved using a receiver operating characteristic curve that the proposed architecture has high contribute to computer‐aided diagnosis of skin lesions. Experiments on a set of 1210 images yielded a specificity of 97.25% and a sensitivity of 91.24%. Their empirical evaluation has a superior retrieval and diagnosis performance when compared to the performance of other works. The authors present explicit combinations of feature vectors corresponding to healthy and lesion skin.
Infrared‐visible video fusion based on motion‐compensated wavelet transforms
Authors: Xu Liang , Du Junping , Zhang Zhenhong
Published: October 2014

Video data fusion should simultaneously take into account both temporal and spatial dimensions, and therefore a novel spatiotemporal video‐fusion algorithm based on motion compensation in the wavelet‐transform domain is proposed in this study. The fusion method incorporates motion compensation and the wavelet transform, thus making full use of spatial geometric information and inter‐frame temporal information of input videos. The proposed method improves the temporal stability and consistency of the fused video compared to other existing individual frame‐based fusion methods. The algorithm first decomposes the image frames which have been processed by an optic flow motion‐compensation approach and then develops a spatiotemporal energy‐based fusion rule to merge input videos. Experimental results demonstrate that the proposed fusion algorithm has superior visual and quantitative performance to traditional individual‐frame‐based and state‐of‐the‐art three‐dimensional‐transform‐based methods.
Moiré fringes characterization of surface plasmon transmission and filtering in multi metal-dielectric films
Authors: Guo Z. , Zhao Z. Y. , Yan L. S. , Gao P. , Wang C. T. , Yao N. , Liu K. P. , Jiang B. , Luo X. G.
Published: October 2014

We use moiré fringes to experimentally characterize the transmission and filtering effect of surface plasmons (SPs) in the alternatively stacked metal-dielectric layers (ASMDLs). Two gratings with unequal periods are introduced at the two sides of films structure to excite SPs and generate moiré fringes observable in the far-field. The observed moiré fringes with specific period agree well with simulations and clearly demonstrate SP with corresponding wave vector transmission and filtering in ASMDLs. By applying variant incidence angle, the fringes contrast fluctuation further illustrate the transmission of SP in a specific wide wave vector band and with an uneven amplitude transmission profile.
C60-dyad aggregates: Self-organized structures in aqueous solutions
Authors: Guskova O. A. , Varanasi S. R. , Sommer J.-U.
Published: October 2014

Extensive full-atomistic molecular dynamics simulations are performed to study the self-organization of C60-fullerene dyad molecules in water, namely phenyl-C61-butyric acid methyl ester and fulleropyrrolidines, which have two elements of ordering, the hydrophobic fullerene cage and the hydrophilic/ionic group. While pristine fullerene or phenyl-C61-butyric acid methyl ester forms spherical droplets in order to minimize the surface tension, the amphiphilic nature of charged solute molecules leads to the formation of supramolecular assemblies having cylindrical shape driven by charge repulsion between the ionic groups located on the surface of the aggregates. We show that formation of non-spherical micelles is the geometrical consequence if the fullerene derivatives are considered as surfactants where the ionized groups are only hydrophilic unit. The agglomeration behavior of fullerenes is evaluated by determining sizes of the clusters, solvent accessible surface areas, and shape parameters. By changing the size of the counterions from chloride over iodide to perchlorate we find a thickening of the cylinder-like structures which can be explained by stronger condensation of larger ions and thus partial screening of the charge repulsion on the cluster surface. The reason for the size dependence of counterion condensation is the formation of a stronger hydration shell in case of small ions which in turn are repelled from the fullerene aggregates. Simulations are also in good agreement with the experimentally observed morphologies of decorated C60-nanoparticles.
Interfacial characterization and electrical properties of Ni–GaSb contacts
Authors: Lin Kun-Lin , Chen Szu-Hung
Published: October 2014

The microstructural characterization of Ni–GaSb junctions in samples annealed at 300 °C, 350 °C, and 400 °C in a N2 atmosphere was elucidated using transmission electron microscopy in conjunction with energy-dispersive spectrometry, nanobeam electron diffraction, and grazing-incident X-ray diffraction. Only the NiSb(Ga) phase is formed at the interface of Ni/GaSb when the annealing temperature is below 350 °C. However, three phases—NiSb, Ni2Ga3, and NiSb(Ga)—are formed simultaneously at the interface between Ni/GaSb when the annealing temperature is increased to 400 °C, which causes a significant increase in the sheet resistance of the Ni–GaSb alloy. These results indicate that the annealing temperature of the Ni/GaSb structure should be maintained below 350 °C for the formation of low-resistance metal Ni/GaSb contacts in GaSb-based p-type metal-oxide-semiconductor field-effect transistors.
Characterization of silicon photomultipliers at National Nano-Fab Center for PET-MR
Authors: Kim Hyoungtaek , Sul Woo Suk , Cho Gyuseong
Published: October 2014

The silicon photomultipliers (SiPMs) were fabricated for magnetic resonance compatible positron emission tomography (PET) applications using customized CMOS processes at National NanoFab Center. Each micro-cell consists of a shallow n+/p well junction on a p-type epitaxial wafer and passive quenching circuit was applied. The size of the SiPM is 3 × 3 mm2 and the pitch of each micro-cell is 65 μm. In this work, several thousands of SiPMs were packaged and tested to build a PET ring detector which has a 60 mm axial and 390 mm radial field of view. I-V characteristics of the SiPMs are shown good uniformity and breakdown voltage is around 20 V. The photon detection efficiency was measured via photon counting method and the maximum value was recorded as 16% at 470 nm. The gamma ray spectrum of a Ge-68 isotope showed nearly 10% energy resolution at 511 keV with a 3 × 3 × 20 mm3 LYSO crystal.
Resonant inelastic x-ray scattering on iso-C2H2Cl2 around the chlorine K-edge: Structural and dynamical aspects
Authors: Kawerk Elie , Carniato Stéphane , Journel Loïc , Marchenko Tatiana , Piancastelli Maria Novella , Žitnik Matjaž , Bučar Klemen , Bohnic Rok , Kavčič Matjaž , Céolin Denis , Khoury Antonio , Simon Marc
Published: October 2014

We report a theoretical and experimental study of the high resolution resonant Kα X-ray emission lines around the chlorine K-edge in gas phase 1,1-dichloroethylene. With the help of ab initio electronic structure calculations and cross section evaluation, we interpret the lowest lying peak in the X-ray absorption and emission spectra. The behavior of the Kα emission lines with respect to frequency detuning highlights the existence of femtosecond nuclear dynamics on the dissociative Potential Energy Surface of the first K-shell core-excited state.
Description of plasmon-like band in silver clusters: The importance of the long-range Hartree-Fock exchange in time-dependent density-functional theory simulations
Authors: Rabilloud Franck
Published: October 2014

Absorption spectra of Ag20 and \documentclass[12pt]{minimal}\begin{document}${\rm Ag}_{55}^q$\end{document} Ag 55q (q = +1, −3) nanoclusters are investigated in the framework of the time-dependent density functional theory in order to analyse the role of the d electrons in plasmon-like band of silver clusters. The description of the plasmon-like band from calculations using density functionals containing an amount of Hartree-Fock exchange at long range, namely, hybrid and range-separated hybrid (RSH) density functionals, is in good agreement with the classical interpretation of the plasmon-like structure as a collective excitation of valence s-electrons. In contrast, using local or semi-local exchange functionals (generalized gradient approximations (GGAs) or meta-GGAs) leads to a strong overestimation of the role of d electrons in the plasmon-like band. The semi-local asymptotically corrected model potentials also describe the plasmon as mainly associated to d electrons, though calculated spectra are in fairly good agreement with those calculated using the RSH scheme. Our analysis shows that a portion of non-local exchange modifies the description of the plasmon-like band.
Nano-fabricated pixelated micropolarizer array for visible imaging polarimetry
Authors: Zhang Zhigang , Dong Fengliang , Cheng Teng , Qiu Kang , Zhang Qingchuan , Chu Weiguo , Wu Xiaoping
Published: October 2014

Pixelated micropolarizer array (PMA) is a novel concept for real-time visible imaging polarimetry. A 320 × 240 aluminum PMA fabricated by electron beam lithography is described in this paper. The period, duty ratio, and depth of the grating are 140 nm, 0.5, and 100 nm, respectively. The units are standard square structures and the metal nanowires of the grating are collimating and uniformly thick. The extinction ratio of 75 and the maximum polarization transmittance of 78.8% demonstrate that the PMA is suitable for polarization imaging. When the PMA is applied to real-time polarization imaging, the degree of linear polarization image and the angle of linear polarization image are calculated from a single frame image. The polarized target object is highlighted from the unpolarized background, and the surface contour of the target object can be reflected by the polarization angle.
Compositional dependence of the bowing parameter for the direct and indirect band gaps in Ge1−ySny alloys
Authors: Gallagher J. D. , Senaratne C. L. , Kouvetakis J. , Menéndez J.
Published: October 2014

Photoluminescence spectroscopy has been used to determine the direct gap E0 of Ge1−ySny alloys over a broad compositional range from pure Ge to Sn concentrations exceeding 10%. A fit of the compositional dependence of E0 using a standard quadratic expression is not fully satisfactory, revealing that the bowing parameter (quadratic coefficient) b0 is compositionally dependent. Excellent agreement with the data is obtained with b0(y) = (2.66 ± 0.09) eV − (5.4 ± 1.1)y eV. A theoretical model of the bowing is presented, which explains the strong compositional dependence of the bowing parameter and suggest a similar behavior for the indirect gap. Combining the model predictions with experimental data for samples with y ≤ 0.06, it is proposed that the bowing parameter for the indirect gap is bind(y) = (1.11 ± 0.07) eV − (0.78 ± 0.05)y eV. The compositional dependence of the bowing parameters shifts the crossover concentration from indirect to direct gap behavior to yc = 0.087, significantly higher than the value predicted earlier based on strictly quadratic fits.
Time and spectrum-resolving multiphoton correlator for 300–900 nm
Authors: Johnsen Kelsey D. , Kolenderski Piotr , Scarcella Carmelo , Thibault Marilyne , Tosi Alberto , Jennewein Thomas
Published: October 2014

We demonstrate a single-photon sensitive spectrometer in the visible range, which allows us to perform time-resolved and multi-photon spectral correlation measurements at room temperature. It is based on a monochromator composed of two gratings, collimation optics, and an array of single photon avalanche diodes. The time resolution can reach 110 ps and the spectral resolution is 2 nm/pixel, limited by the design of the monochromator. This technique can easily be combined with commercial monochromators and can be useful for joint spectrum measurements of two photons emitted in the process of parametric down conversion, as well as time-resolved spectrum measurements in optical coherence tomography or medical physics applications.
Turbulent transport across shear layers in magnetically confined plasmas
Authors: Nold B. , Manz P. , Ribeiro T. T. , Fuchert G. , Birkenmeier G. , Müller H. W. , Ramisch M. , Scott B. D. , Stroth U.
Published: October 2014

Shear layers modify the turbulence in diverse ways and do not only suppress it. A spatial-temporal investigation of gyrofluid simulations in comparison with experiments allows to identify further details of the transport process across shear layers. Blobs in and outside a shear layer merge, thereby exchange particles and heat and subsequently break up. Via this mechanism particles and heat are transported radially across shear layers. Turbulence spreading is the immanent mechanism behind this process.
Determination of reaction flux from concentration fluctuations near a Hopf bifurcation
Authors: Bianca C. , Lemarchand A.
Published: October 2014

Small open chemical systems, typically associated with far-from-equilibrium, nonlinear stochastic dynamics, offer the appropriate framework to elucidate biological phenomena at the cellular scale. Stochastic differential equations of Langevin-type are employed to establish the relation between the departure from equilibrium and the time cross-correlation functions of concentration fluctuations for chemical species susceptible to oscillate. Except in the immediate vicinity of the Hopf bifurcation, the results are in agreement with simulations of the chemical master equation but always differ from the prediction obtained for linear deterministic dynamics. In general, the magnitude of the asymmetry of time correlation functions definitely depends on the reaction flux circulating in an open system but also on the details of the nonlinearities of deterministic dynamics.
Non-linear Langmuir waves in a warm quantum plasma
Authors: Dubinov Alexander E. , Kitaev Ilya N.
Published: October 2014

A non-linear differential equation describing the Langmuir waves in a warm quantum electron-ion plasma has been derived. Its numerical solutions of the equation show that ordinary electronic oscillations, similar to the classical oscillations, occur along with small-scale quantum Langmuir oscillations induced by the Bohm quantum force.
Bias-temperature instability in single-layer graphene field-effect transistors
Authors: Illarionov Yu. Yu. , Smith A. D. , Vaziri S. , Ostling M. , Mueller T. , Lemme M. C. , Grasser T.
Published: October 2014

We present a detailed analysis of the bias-temperature instability (BTI) of single-layer graphene field-effect transistors. Both negative BTI and positive BTI can be benchmarked using models developed for Si technologies. In particular, recovery follows the universal relaxation trend and can be described using the established capture/emission time map approach. We thereby propose a general methodology for assessing the reliability of graphene/dielectric interfaces, which are essential building blocks of graphene devices.
Augmented photocatalytic activity and luminescence response of Tb3+ doped nanoscale titania systems
Authors: Paul Nibedita , Deka Amrita , Mohanta Dambarudhar
Published: October 2014

The present work reports on the effect of Tb3+ doping on the luminescence and photocatalytic performance of nano-structured titania derived through a sol-gel route. X-ray diffraction patterns have revealed the existence of anatase phase with and without Tb3+ doping and with an improved orientation factor along (004) and (200) planes. Transmission electron microscopy and selective area electron diffraction studies, while exhibiting ample poly-crystallinity feature, have predicted an average particle size of ∼9 nm and ∼6 nm for the un-doped and 5% Tb3+ doped nano-titania samples; respectively. Apart from emissions accompanied by different types of defects, Tb3+ related transitions, such as, 5D3 → 7F5, 5D3 → 7F4, and 5D4 → 7F6 were identified in the photoluminescence spectra. Brunauer-Emmett-Teller surface area analysis, as carried out on a Tb3+ doped nano-titania system, has demonstrated a more-open hysteretic loop owing to significant difference of N2 adsorption/desorption rates. The photocatalytic activity of nano-titania, as evaluated from the nature of degradation of methyl orange under UV illumination, exhibited the highest efficiency for a Tb3+ doping level of 2.5%. The augmented photocatalytic degradation has also been discussed in the light of a model based on pseudo first-order kinetics.
Glass formation and the third harmonic generation of Cu2Se–GeSe2–As2Se3 glasses
Authors: Reshak A. H. , Klymovych O. S. , Myronchuk G. L. , Zamuruyeva O. V. , Zmiy O. F. , Alahmed Z. A. , Chyský J. , Bila Jiri , Kamarudin H.
Published: October 2014

We have performed the investigation of the nonlinear optical properties namely the third harmonic generation (THG) of the glass-formation region in the Cu2Se–GeSe2–As2Se3 system. The samples were synthesized by direct single-temperature method from high-purity elementary substances. We have found that the value of disorder parameter Δ depends on the composition of the glassy alloys. The measurements show that increasing the Cu2Se concentration leads to increased slope of the absorption edge, which may be explained by the decrease of the height of random potential relief for the electrons in the tails of the state density which border the band edges. A very sharp increase in the THG at low temperature was observed. Significant enhancement in THG was obtained with decreasing the energy gap, which agreed well with the nonlinear optical susceptibilities obtained from other glasses.
Edge effects on the electronic properties of phosphorene nanoribbons
Authors: Peng Xihong , Copple Andrew , Wei Qun
Published: October 2014

Two dimensional few-layer black phosphorus crystal structures have recently been fabricated and have demonstrated great potential in electronic applications. In this work, we employed first principles density functional theory calculations to study the edge and quantum confinement effects on the electronic properties of the phosphorene nanoribbons (PNR). Different edge functionalization groups, such as H, F, Cl, OH, O, S, and Se, in addition to a pristine case were studied for a series of ribbon widths up to 3.5 nm. It was found that the armchair-PNRs (APNRs) are semiconductors for all edge groups considered in this work. However, the zigzag-PNRs (ZPNRs) show either semiconductor or metallic behavior in dependence on their edge chemical species. Family 1 edges (i.e., H, F, Cl, OH) form saturated bonds with P atoms in the APNRs and ZPNRs, and the edge states keep far away from the band gap. However, Family 2 edges (pristine, O, S, Se) form weak unsaturated bonds with the pz orbital of the phosphorus atoms and bring edge states within the band gap of the ribbons. For the ZPNRs, the edge states of Family 2 are present around the Fermi level within the band gap, which close up the band gap of the ZPNRs. For the APNRs, these edge states are located at the bottom of the conduction band and result in a reduced band gap.
Spin Hall magnetoresistance at Pt/CoFe2O4 interfaces and texture effects
Authors: Isasa Miren , Bedoya-Pinto Amilcar , Vélez Saül , Golmar Federico , Sánchez Florencio , Hueso Luis E. , Fontcuberta Josep , Casanova Fèlix
Published: October 2014

We report magnetoresistance measurements on thin Pt bars grown on epitaxial (001) and (111) CoFe2O4 (CFO) ferrimagnetic insulating films. The results can be described in terms of the recently discovered spin Hall magnetoresistance (SMR). The magnitude of the SMR depends on the interface preparation conditions, being optimal when the Pt/CFO samples are prepared in situ, in a single process. The spin-mixing interface conductance, the key parameter governing SMR and other relevant spin-dependent phenomena, such as spin pumping or spin Seebeck effect, is found to be different depending on the crystallographic orientation of CFO, highlighting the role of the composition and density of magnetic ions at the interface on spin mixing.
Numerical simulation of heat and mass transfer in unsteady nanofluid between two orthogonally moving porous coaxial disks
Authors: Ali Kashif , Akbar Muhammad Zubair , Iqbal Muhammad Farooq , Ashraf Muhammad
Published: October 2014

The paper deals with the study of heat and mass transfer in an unsteady viscous incompressible water-based nanofluid (containing Titanium dioxide nanoparticles) between two orthogonally moving porous coaxial disks with suction. A combination of iterative (successive over relaxation) and a direct method is employed for solving the sparse systems of linear algebraic equations arising from the FD discretization of the linearized self similar ODEs. It has been noticed that the rate of mass transfer at the disks decreases with the permeability Reynolds number whether the disks are approaching or receding. The findings of the present investigation may be beneficial for the electronic industry in maintaining the electronic components under effective and safe operational conditions.
Expression of group III metabotropic glutamate receptors in the reproductive system of male mice
Authors: Marciniak Marcin , Chruścicka Barbara , Lech Tomasz , Burnat Grzegorz , Pilc Andrzej
Published: October 2014

Although the presence of metabotropic glutamate (mGlu) receptors in the central nervous system is well documented, they have recently been found in peripheral and non-neuronal tissues. In the present study we investigated the expression of group III mGlu receptors in the reproductive system of male mice. Reverse transcription–polymerase chain reaction analysis revealed the presence of mGlu6, mGlu7 and mGlu8 (but not mGlu4) receptor transcripts in testes and epididymides from adult mice. In addition, expression of mGlu6 (Grm6) and mGlu8 receptor (Grm8) mRNA was detected in spermatozoa isolated from the vas deferens. The vas deferens was found to contain only mGlu7 receptor (Grm7) mRNA, which was particularly intense in 21-day-old male mice. In penile homogenates, only the mGlu7 receptor signal was detected. Genetic ablation of the mGlu7 receptor in males led to fertility disorders manifested by decreased insemination capability as well as deterioration of sperm parameters, particularly sperm motility, vitality, sperm membrane integrity and morphology, with a simultaneous increase in sperm concentration. These results indicate that constitutively expressed mGlu receptors in the male reproductive system may play an important role in ejaculation and/or erection processes, as well as in the formation and maturation of spermatozoa.
Determinants of valid measurements of global changes in 5ʹ-methylcytosine and 5ʹ-hydroxymethylcytosine by immunolocalisation in the early embryo
Authors: Salvaing J. , Li Y. , Beaujean N. , O'Neill C.
Published: October 2014

A classical model of epigenetic reprogramming of methyl-cytosine–phosphate–guanine (CpG) dinucleotides within the genome of the early embryo involves a process of active demethylation of the paternally derived genome immediately following fertilisation, creating marked asymmetry in global cytosine methylation levels in male and female pronuclei, followed by passive demethylation of the maternally derived genome over subsequent cell cycles. This model has dominated thinking in developmental epigenetics over recent decades. Recent re-analyses of the model show that demethylation of the paternally derived genome is more modest than formerly thought and results in overall similar levels of methylation of the paternal and maternal pronuclei in presyngamal zygotes, although there is little evidence for a pervasive process of passive demethylation during the cleavage stage of development. In contrast, the inner cell mass of the blastocyst shows some loss of methylation within specific classes of loci. Improved methods of chemical analysis now allow global base-level analysis of modifications to CpG dinucleotides within the cells of the early embryo, yet the low cost and convenience of the immunolocalisation techniques mean that they still have a valuable place in the analysis of the epigenetics of embryo development. In this review we consider the key strengths and weaknesses of this methodology and some factors required for its valid use and interpretation.
Fate of urine nitrogen through a volcanic vadose zone
Authors: Barkle G. F. , Stenger R. , Wöhling Th.
Published: October 2014

To investigate the fate of nitrogen (N) from urine, dairy cow urine was amended with bromide (Br) and chloride (Cl), and applied onto a loamy sand soil with an underlying vadose zone of gritty coarse sands and pumice fragments with groundwater at ~5.5 m depth. Textural changes and hydrophobicity resulted in heterogeneous flow and high variability in the Cl, Br and N masses captured. Three forms of N derived from the urine, organic-N (org-N), ammonium-N (NH4-N) and nitrate-N (NO3-N), were measured at 0.4 m depth. At 1.0 m depth, effectively all measured N was NO3-N. At 4.2 m, the mass of recovered N (average 33% of applied N, s.d. 21%), although solely speciated as NO3-N, was not significantly different from that at 0.4 m (average 24.5% of applied N, s.d. 0.1%), suggesting that no substantial assimilation of NO3-N had occurred in this vadose zone. Below the interface of the Taupo Ignimbrite and the Palaeosol at 4.2 m depth, recoveries of the Cl and Br tracers were negligible. In addition, the isotopic signatures (δ18O and δ15N) of the nitrate were different and the NO3-N concentrations were higher than in the upper vadose zone. These results all suggest that the Palaeosol was acting as a hydraulically limiting layer resulting in lateral unsaturated flow occurring at this interface. The fact that no nitrate assimilation was observed in this field study, despite previous laboratory studies showing substantial assimilative capacity, underlines that that the nitrate assimilative capacity in the vadose zone is a function of both hydrological and biogeochemical factors.