bluuebunny/crossref_metadata_2025 huggingface dataset:
Raman spectral signatures for the differentiation of benzodiazepine drugs
Authors: Montalvo Gemma , López-Melero Lucía , Ortega-Ojeda Fernando , Peña María Ángeles , García-Ruiz Carmen
Published: September 2014

Raman methodology to differentiate benzodiazepines based on their spectral signature.
A highly selective long-wavelength fluorescent probe for the detection of human carboxylesterase 2 and its biomedical applications
Authors: Feng Lei , Liu Zhao-Ming , Xu Liang , Lv Xia , Ning Jing , Hou Jie , Ge Guang-Bo , Cui Jing-Nan , Yang Ling
Published: September 2014

A highly selective long-wavelength fluorescent probe for the detection of human carboxylesterase 2 (hCE2) has been developed and well characterized. The probe can be used for measuring the real activities of hCE2 in complex biological systems.
Self-catalytic synthesis of metal oxide nanoclusters@mesoporous silica composites based on successive spontaneous reactions at near neutral conditions
Authors: Cui Fang , Cui Tieyu
Published: September 2014

We report a self-catalytic strategy for the facile synthesis of metal oxide nanoclusters@mesoporous silica by subtly making use of successive spontaneous reactions (i.e. nucleophilic substitution, self-catalytic hydrolyzation and polycondensation reaction) in water–ethanol solution at near neutral conditions.
3D hierarchical anatase TiO2 superstructures constructed by “nanobricks” built nanosheets with exposed {001} facets: facile synthesis, formation mechanism and superior photocatalytic activity
Authors: Li Guoliang , Liu Jiyan , Lan Jing , Li Gang , Chen Qiuwen , Jiang Guibin
Published: September 2014

3D hierarchical anatase TiO2 superstructures with exposed {001} facets were synthesized through a simple one-pot route, which exhibit superior photocatalytic activity.
Understanding the amino ↔ imino tautomeric preference in (imidazole)imidazolidine-N-aryl(alkyl) systems: a case study of moxonidine drug and insights from the Cambridge structural database (CSD)
Authors: Babu Nanubolu Jagadeesh , Sridhar Balasubramanian , Ravikumar Krishnan
Published: September 2014

Moxonidine drug crystallizes exclusively as its imino tautomer. Conjugation plays a key role in the tautomer stability.
Computational design of inorganic nonlinear optical crystals based on a genetic algorithm
Authors: Fang Zhenxing , Lin Jing , Liu Rong , Liu Ping , Li Yi , Huang Xin , Ding Kaining , Ning Lixin , Zhang Yongfan
Published: September 2014

A theoretical method to design inorganic nonlinear optical crystals for second harmonic generation (SHG) is presented here.
Directed synthesis of a halogen-bonded open porphyrin network
Authors: Syssa-Magalé Jean-Laurent , Boubekeur Kamal , Leroy Jacques , Chamoreau Lise-Marie , Fave Claire , Schöllhorn Bernd
Published: September 2014

A strategy for the elaboration of a halogen-bonded porphyrin network with nano-sized tubular channels is reported.
Crystal-to-crystal transformations and photoluminescence changes in the Cu(i) coordination networks based on a formamidinate ligand
Authors: Hsu Wayne , Chen Kuan-Ting , Li Yu-Sian , Cheng Po-Wen , Chen Tsun-Ren , Chen Jhy-Der
Published: September 2014

While the syn-complexes show broad emission bands, those of the anti-complexes are not detectable, indicating that cuprophilicity is unlikely to play a significant role in determining the emission.
Flue gas CO2 mineralization using thermally activated serpentine: from single- to double-step carbonation
Authors: Werner Mischa , Hariharan Subrahmaniam , Mazzotti Marco
Published: September 2014

A new CO2 mineralization route is presented and assessed that integrates CO2 capture by exploiting a T–pCO2-swing in a double-step arrangement.
A hybrid DFT based investigation of the photocatalytic activity of cation–anion codoped SrTiO3 for water splitting under visible light
Authors: Modak Brindaban , Srinivasu K. , Ghosh Swapan K.
Published: September 2014

The effect of cation (Mo or W) and anion (N) codoping in different proportion has been explored to improve the photocatalytic activity of SrTiO3 under visible light. Codoping in 1 : 2 ratio has been found to be more effective due to reduction in band gap without introducing local trapping center and also for maintaining appropriate band alignment.
Investigation of ESIPT in a panel of chromophores presenting N–H⋯N intramolecular hydrogen bonds
Authors: Hubin Pierre O. , Laurent Adèle D. , Vercauteren Daniel P. , Jacquemin Denis
Published: September 2014

We explore the ESIPT process in N–H⋯N compounds using both TD-DFT and EOM-CCSD.
Shallow-tunnelling correction factor for use with Wigner–Eyring transition-state theory
Authors: Zhang Yanchuan , Rommel Judith B. , Cvitaš Marko T. , Althorpe Stuart C.
Published: September 2014

We obtain a shallow-tunnelling correction factor for use with Wigner–Eyring transition-state theory (TST).
New molecular-scale information on polystyrene dynamics in PS and PS–BaTiO3composites from FTIR spectroscopy
Authors: Olmos D. , Martín E. V. , González-Benito J.
Published: September 2014

A study of thermal relaxations in PS and PS–BaTiO3composites using FTIR spectroscopy: in-depth analysis and new molecular-scale information.
Mesoporous Li4Ti5O12−x/C submicrospheres with comprehensively improved electrochemical performances for high-power lithium-ion batteries
Authors: Lin Chunfu , Lai Man On , Zhou Henghui , Lu Li
Published: September 2014

Monodispersed/multidispersed mesoporous Li4Ti5O12−x/C submicrospheres were fabricated through a synergistic method, and exhibit comprehensively improved material properties and electrochemical performances.
Panchromatic symmetrical squaraines: a step forward in the molecular engineering of low cost blue-greenish sensitizers for dye-sensitized solar cells
Authors: Park J. , Barbero N. , Yoon J. , Dell'Orto E. , Galliano S. , Borrelli R. , Yum J.-H. , Di Censo D. , Grätzel M. , Nazeeruddin Md. K. , Barolo C. , Viscardi G.
Published: September 2014

A new series of low cost dibranched symmetrical blue-greenish squaraines showing interesting photovoltaic properties and photostabilities is reported.
Tailored graphene systems for unconventional applications in energy conversion and storage devices
Authors: Hu Chuangang , Song Long , Zhang Zhipan , Chen Nan , Feng Zhihai , Qu Liangti
Published: September 2014

Graphene-based materials have shown great potential in various fields across physics, chemistry, biology, and electronics, due to their unique electronic properties, facile synthesis, and ease of functionalization.
Measurement of organic and elemental carbon in downtown Rome and background area: physical behavior and chemical speciation
Authors: Avino Pasquale , Manigrasso Maurizio , Rosada Alberto , Dodaro Alessandro
Published: September 2014

PM10 carbonaceous fraction in urban air and at a background site is deeply investigated in terms of physical behavior (spatial, vertical and temporal trends) and chemical composition (elements, ions, organic fraction).
In vitro study of the interaction of heregulin-functionalized magnetic–optical nanorods with MCF7 and MDA-MB-231 cells
Authors: Lesniak A. , Kilinc D. , Rashdan Suad A. , von Kriegsheim A. , Ashall B. , Zerulla D. , Kolch W. , Lee G. U.
Published: September 2014

Multifunctional nanoparticles that actively target specific cells are promising tools for cancer diagnosis and therapy. In this article we review the synthesis and surface chemistry of Fe–Au nanorods and their characterization using microscopy. The diameter of the rods used in this study was selected to be 150–200 nm so that they did not enter the cells. The 80 nm-long Au tips of the nanorods were functionalized with heregulin (HRG), and the micron-long Fe portion was coated with a poly(ethylene glycol) monolayer to minimize non-specific interactions. Nanorods functionalized with HRG were found to preferentially bind to MCF7 cells that express high levels of the receptor tyrosine-protein kinase ErbB2/3. Magnetic tweezers measurements were used to characterize the kinetic properties of the bond between the HRG on the rods and ErbB2/3 on the surface of the cells. The strong magnetization of Fe–Au nanorods makes them excellent candidates for in-vitro and in-vivo imaging, and magnetic therapeutic applications targeting cancer cells in circulation.
Pressure stabilizer for reproducible picoinjection in droplet microfluidic systems
Authors: Rhee Minsoung , Light Yooli K. , Yilmaz Suzan , Adams Paul D. , Saxena Deepak , Meagher Robert J. , Singh Anup K.
Published: September 2014

Our novel pressure balancing structure stabilizes a picoinjector, allowing reagent injection into flowing droplets in channels with fluctuating pressure.
CCK8 peptide-labeled Pluronic® F127 micelles as a targeted vehicle of gold-based anticancer chemotherapeutics
Authors: Nardon Chiara , Boscutti Giulia , Dalla Via Lisa , Ringhieri Paola , Di Noto Vito , Morelli Giancarlo , Accardo Antonella , Fregona Dolores
Published: September 2014

A sparingly water-soluble gold(iii) complex was encapsulated in micelles functionalized with the CCK8-targeting moiety for the selective delivery of an anticancer drug.
Attenuation of quorum sensing-mediated virulence in Gram-negative pathogenic bacteria: implications for the post-antibiotic era
Authors: Singh Ravindra Pal
Published: September 2014

Quorum quenching compounds blocked quorum sensing system of bacteria by several mechanisms (a, b, c and d).
Mesoporous titania based yolk–shell nanoparticles as multifunctional theranostic platforms for SERS imaging and chemo-photothermal treatment
Authors: Zhang Weiwei , Wang Yunqing , Sun Xiuyan , Wang Wenhai , Chen Lingxin
Published: September 2014

Chemical inert and biocompatible mesoporous titania (mTiO2) based yolk–shell AuNR@void@mTiO2 nanoparticles for simultaneous SERS imaging and chemo-photothermal therapy.
Pd-catalyzed oxidative C–H alkenylation for synthesizing arylvinyltriazole nucleosides
Authors: Tang Jingjie , Cong Mei , Xia Yi , Quéléver Gilles , Fan Yuting , Qu Fanqi , Peng Ling
Published: September 2014

Pd-catalyzed oxidative C–H alkenylation: an effective method for synthesizing arylvinyltriazole nucleosides in good yields and with large functional group tolerance.
Droplet coalescence on water repellant surfaces
Authors: Nam Youngsuk , Seo Donghyun , Lee Choongyeop , Shin Seungwon
Published: September 2014

We report our hydrodynamic and energy analyses of droplet coalescence on water repellent surfaces including hydrophobic, superhydrophobic and oil-infused superhydrophobic surfaces.
Effects of side chain isomerism on the physical and photovoltaic properties of indacenodithieno[3,2-b]thiophene–quinoxaline copolymers: toward a side chain design for enhanced photovoltaic performance
Authors: Xu Xiaofeng , Li Zhaojun , Bäcke Olof , Bini Kim , James David I. , Olsson Eva , Andersson Mats R. , Wang Ergang
Published: September 2014

Polymers based on quinoxaline and indacenodithieno[3,2-b]thiophene (IDTT) withmeta-hexyl-phenyl side chains were synthesized.
1H-NMR metabolite profiles of different strains ofPlasmodium falciparum
Authors: Teng Rongwei , Lehane Adele M. , Winterberg Markus , Shafik Sarah H. , Summers Robert L. , Martin Rowena E. , van Schalkwyk Donelly A. , Junankar Pauline R. , Kirk Kiaran
Published: September 2014

Although efforts to understand the basis for inter-strain phenotypic variation in the most virulent malaria species, Plasmodium falciparum, have benefited from advances in genomic technologies, there have to date been few metabolomic studies of this parasite. Using 1H-NMR spectroscopy, we have compared the metabolite profiles of red blood cells infected with different P. falciparum strains. These included both chloroquine-sensitive and chloroquine-resistant strains, as well as transfectant lines engineered to express different isoforms of the chloroquine-resistance-conferring pfcrt (P. falciparum chloroquine resistance transporter). Our analyses revealed strain-specific differences in a range of metabolites. There was marked variation in the levels of the membrane precursors choline and phosphocholine, with some strains having >30-fold higher choline levels and >5-fold higher phosphocholine levels than others. Chloroquine-resistant strains showed elevated levels of a number of amino acids relative to chloroquine-sensitive strains, including an approximately 2-fold increase in aspartate levels. The elevation in amino acid levels was attributable to mutations in pfcrt. Pfcrt-linked differences in amino acid abundance were confirmed using alternate extraction and detection (HPLC) methods. Mutations acquired to withstand chloroquine exposure therefore give rise to significant biochemical alterations in the parasite.
A segmented multi-loop antenna for selective excitation of azimuthal mode number in a helicon plasma source
Authors: Shinohara S. , Tanikawa T. , Motomura T.
Published: September 2014

A flat type, segmented multi-loop antenna was developed in the Tokai Helicon Device, built for producing high-density helicon plasma, with a diameter of 20 cm and an axial length of 100 cm. This antenna, composed of azimuthally splitting segments located on four different radial positions, i.e., r = 2.8, 4.8, 6.8, and 8.8 cm, can excite the azimuthal mode number m of 0, ±1, and ±2 by a proper choice of antenna feeder parts just on the rear side of the antenna. Power dependencies of the electron density ne were investigated with a radio frequency (rf) power less than 3 kW (excitation frequency ranged from 8 to 20 MHz) by the use of various types of antenna segments, and ne up to ∼5 × 1012 cm−3 was obtained after the density jump from inductively coupled plasma to helicon discharges. Radial density profiles of m = 0 and ±1 modes with low and high rf powers were measured. For the cases of these modes after the density jump, the excited mode structures derived from the magnetic probe measurements were consistent with those expected from theory on helicon waves excited in the plasma.
Accurate small and wide angle x-ray scattering profiles from atomic models of proteins and nucleic acids
Authors: Nguyen Hung T. , Pabit Suzette A. , Meisburger Steve P. , Pollack Lois , Case David A.
Published: September 2014

A new method is introduced to compute X-ray solution scattering profiles from atomic models of macromolecules. The three-dimensional version of the Reference Interaction Site Model (RISM) from liquid-state statistical mechanics is employed to compute the solvent distribution around the solute, including both water and ions. X-ray scattering profiles are computed from this distribution together with the solute geometry. We describe an efficient procedure for performing this calculation employing a Lebedev grid for the angular averaging. The intensity profiles (which involve no adjustable parameters) match experiment and molecular dynamics simulations up to wide angle for two proteins (lysozyme and myoglobin) in water, as well as the small-angle profiles for a dozen biomolecules taken from the BioIsis.net database. The RISM model is especially well-suited for studies of nucleic acids in salt solution. Use of fiber-diffraction models for the structure of duplex DNA in solution yields close agreement with the observed scattering profiles in both the small and wide angle scattering (SAXS and WAXS) regimes. In addition, computed profiles of anomalous SAXS signals (for Rb+ and Sr2+) emphasize the ionic contribution to scattering and are in reasonable agreement with experiment. In cases where an absolute calibration of the experimental data at q = 0 is available, one can extract a count of the excess number of waters and ions; computed values depend on the closure that is assumed in the solution of the Ornstein–Zernike equations, with results from the Kovalenko–Hirata closure being closest to experiment for the cases studied here.
IETS and quantum interference: Propensity rules in the presence of an interference feature
Authors: Lykkebo Jacob , Gagliardi Alessio , Pecchia Alessandro , Solomon Gemma C.
Published: September 2014

Destructive quantum interference in single molecule electronics is an intriguing phenomenon; however, distinguishing quantum interference effects from generically low transmission is not trivial. In this paper, we discuss how quantum interference effects in the transmission lead to either low current or a particular line shape in current-voltage curves, depending on the position of the interference feature. Second, we consider how inelastic electron tunneling spectroscopy can be used to probe the presence of an interference feature by identifying vibrational modes that are selectively suppressed when quantum interference effects dominate. That is, we expand the understanding of propensity rules in inelastic electron tunneling spectroscopy to molecules with destructive quantum interference.
Wake pattern and wave resistance for anisotropic moving disturbances
Authors: Benzaquen Michael , Darmon Alexandre , Raphaël Elie
Published: September 2014

We present a theoretical study of gravity waves generated by an anisotropic moving disturbance. We model the disturbance by an elliptical pressure field of given aspect ratio \documentclass[12pt]{minimal}\begin{document}$\mathcal {W}$\end{document}W. We study the wake pattern as a function of \documentclass[12pt]{minimal}\begin{document}$\mathcal {W}$\end{document}W and the longitudinal hull Froude number \documentclass[12pt]{minimal}\begin{document}$Fr = V/\sqrt{gL}$\end{document}Fr=V/gL, where V is the velocity, g is the acceleration of gravity, and L is the size of the disturbance in the direction of motion. For large hull Froude numbers, we analytically show that the rescaled surface profiles for which \documentclass[12pt]{minimal}\begin{document}$\sqrt{\mathcal {W}}/Fr$\end{document}W/Fr is kept constant coincide. In particular, the angle outside which the surface is essentially flat remains constant and equal to the Kelvin angle, and the angle corresponding to the maximum amplitude of the waves scales as \documentclass[12pt]{minimal}\begin{document}$\sqrt{\mathcal {W}}/Fr$\end{document}W/Fr, thus showing that previous work on the wake's angle for isotropic objects can be extended to anisotropic objects of given aspect ratio. We then focus on the wave resistance and discuss its properties in the case of an elliptical Gaussian pressure field. We derive an analytical expression for the wave resistance in the limit of very elongated objects and show that the position of the speed corresponding to the maximum wave resistance scales as \documentclass[12pt]{minimal}\begin{document}$\sqrt{gL}/\sqrt{\mathcal {W}}$\end{document}gL/W.
On the dimensions of oscillator algebras induced by orthogonal polynomials
Authors: Honnouvo G. , Thirulogasanthar K.
Published: September 2014

There is a generalized oscillator algebra associated with every class of orthogonal polynomials \documentclass[12pt]{minimal}\begin{document}$\lbrace \Psi _n(x)\rbrace _{n = 0}^{\infty }$\end{document}{Ψn(x)}n=0∞, on the real line, satisfying a three term recurrence relation xΨn(x) = bnΨn+1(x) + bn−1Ψn−1(x), Ψ0(x) = 1, b−1 = 0. This note presents necessary and sufficient conditions on bn for such algebras to be of finite dimension. As examples, we discuss the dimensions of oscillator algebras associated with Hermite, Legendre, and Gegenbauer polynomials. Some remarks on the dimensions of oscillator algebras associated with multi-boson systems are also presented.
Suppression of stochastic pinning in magnetic nanowire devices using “virtual” domain walls
Authors: Hodges M. P. P. , Bryan M. T. , Fry P. W. , Im M.-Y. , Fischer P. , Hayward T. J.
Published: September 2014

We have investigated the pinning and depinning of “virtual” domain walls in planar magnetic nanowires. Such virtual walls are created when a conventional domain wall becomes annihilated at a narrow gap between two segments of a discontinuous nanowire. By using focused magneto-optical Kerr effect magnetometry to study the repeatability of their depinning, we show that virtual walls exhibit single-mode depinning distributions, characterized by remarkably low, sub-Oersted standard deviations. This is in stark contrast to the depinning of domain walls from conventional notch-shaped defects, which typically exhibit multi-mode depinning field distributions spanning tens to hundreds of Oersteds. High-resolution magnetic soft x-ray microscopy measurements are used to reveal that this high level of repeatability is the result of a simple mediated-nucleation process, which decouples the depinning mechanism from structure of the initially injected DWs. Our work serves as an example of how the complex and dynamical stochastic behaviors exhibited by domain walls in nanowires can be controlled.
Assessment of approximate computational methods for conical intersections and branching plane vectors in organic molecules
Authors: Nikiforov Alexander , Gamez Jose A. , Thiel Walter , Huix-Rotllant Miquel , Filatov Michael
Published: September 2014

Quantum-chemical computational methods are benchmarked for their ability to describe conical intersections in a series of organic molecules and models of biological chromophores. Reference results for the geometries, relative energies, and branching planes of conical intersections are obtained using ab initio multireference configuration interaction with single and double excitations (MRCISD). They are compared with the results from more approximate methods, namely, the state-interaction state-averaged restricted ensemble-referenced Kohn-Sham method, spin-flip time-dependent density functional theory, and a semiempirical MRCISD approach using an orthogonalization-corrected model. It is demonstrated that these approximate methods reproduce the ab initio reference data very well, with root-mean-square deviations in the optimized geometries of the order of 0.1 Å or less and with reasonable agreement in the computed relative energies. A detailed analysis of the branching plane vectors shows that all currently applied methods yield similar nuclear displacements for escaping the strong non-adiabatic coupling region near the conical intersections. Our comparisons support the use of the tested quantum-chemical methods for modeling the photochemistry of large organic and biological systems.
Structure and transport of aqueous electrolytes: From simple halides to radionuclide ions
Authors: Hartkamp Remco , Coasne Benoit
Published: September 2014

Molecular simulations are used to compare the structure and dynamics of conventional and radioactive aqueous electrolytes: chloride solutions with sodium, potassium, cesium, calcium, and strontium. The study of Cs+ and Sr2+ is important because these radioactive ions can be extremely harmful and are often confused by living organisms for K+ and Ca2+, respectively. Na+, Ca2+, and Sr2+ are strongly bonded to their hydration shell because of their large charge density. We find that the water molecules in the first hydration shell around Na+ form hydrogen bonds between each other, whereas molecules in the first hydration shell around Ca2+ and Sr2+ predominantly form hydrogen bonds with water molecules in the second shell. In contrast to these three ions, K+ and Cs+ have low charge densities so that they are weakly bonded to their hydration shell. Overall, the structural differences between Ca2+ and Sr2+ are small, but the difference between their coordination numbers relative to their surface areas could potentially be used to separate these ions. Moreover, the different decays of the velocity-autocorrelation functions corresponding to these ions indicates that the difference in mass could be used to separate these cations. In this work, we also propose a new definition of the pairing time that is easy to calculate and of physical significance regardless of the problem at hand.
Characterization of buried metal-molecule-metal junctions using Fourier transform infrared microspectroscopy
Authors: Babayco Christopher B. , Land Donald P. , Parikh Atul N. , Kiehl Richard A.
Published: September 2014

We have devised an infrared spectromicroscopy based experimental configuration to enable structural characterization of buried molecular junctions. Our design utilizes a small mercury drop at the focal point of an infrared microscope to act as a mirror in studying metal-molecule-metal (MmM) junctions. An organic molecular monolayer is formed either directly on the mercury drop or on a thin, infrared (IR) semi-transparent layer of Au deposited onto an IR transparent, undoped silicon substrate. Following the formation of the monolayer, films on either metal can be examined independently using specular reflection spectroscopy. Furthermore, by bringing together the two monolayers, a buried molecular bilayer within the MmM junction can be characterized. Independent examination of each half of the junction prior to junction formation also allows probing any structural and/or conformational changes that occur as a result of forming the bilayer. Because our approach allows assembling and disassembling microscopic junctions by forming and withdrawing Hg drops onto the monolayer covered metal, spatial mapping of junctions can be performed simply by translating the location of the derivatized silicon wafer. Finally, the applicability of this technique for the longer-term studies of changes in molecular structure in the presence of electrical bias is discussed.
Communication: Molecular-level insights into asymmetric triblock copolymers: Network and phase development
Authors: Tallury Syamal S. , Mineart Kenneth P. , Woloszczuk Sebastian , Williams David N. , Thompson Russell B. , Pasquinelli Melissa A. , Banaszak Michal , Spontak Richard J.
Published: September 2014

Molecularly asymmetric triblock copolymers progressively grown from a parent diblock copolymer can be used to elucidate the phase and property transformation from diblock to network-forming triblock copolymer. In this study, we use several theoretical formalisms and simulation methods to examine the molecular-level characteristics accompanying this transformation, and show that reported macroscopic-level transitions correspond to the onset of an equilibrium network. Midblock conformational fractions and copolymer morphologies are provided as functions of copolymer composition and temperature.
Quantum Hall effect in HgTe quantum wells at nitrogen temperatures
Authors: Kozlov D. A. , Kvon Z. D. , Mikhailov N. N. , Dvoretskii S. A. , Weishäupl S. , Krupko Y. , Portal J.-C.
Published: September 2014

We report on the observation of quantized Hall plateaus in a system of two-dimensional Dirac fermions, implemented in a 6.6 nm HgTe quantum well at magnetic fields up to 34 T at nitrogen temperatures. The activation energies determined from the temperature dependence of the longitudinal resistivity are found to be almost equal for the filling factors ν of 1 and 2. This indicates that the large values of the g-factor (about 30–40) remain unchanged at very strong magnetic fields.
Potential variations around grain boundaries in impurity-doped BaSi2 epitaxial films evaluated by Kelvin probe force microscopy
Authors: Tsukahara D. , Baba M. , Honda S. , Imai Y. , Hara K. O. , Usami N. , Toko K. , Werner J. H. , Suemasu T.
Published: September 2014

Potential variations around the grain boundaries (GBs) in antimony (Sb)-doped n-type and boron (B)-doped p-type BaSi2 epitaxial films on Si(111) were evaluated by Kelvin probe force microscopy. Sb-doped n-BaSi2 films exhibited positively charged GBs with a downward band bending at the GBs. The average barrier height for holes was approximately 10 meV for an electron concentration n ≈ 1017 cm−3. This downward band bending changed to upward band bending when n was increased to n = 1.8 × 1018 cm−3. In the B-doped p-BaSi2 films, the upward band bending was observed for a hole concentration p ≈ 1018 cm−3. The average barrier height for electrons decreased from approximately 25 to 15 meV when p was increased from p = 2.7 × 1018 to p = 4.0 × 1018 cm−3. These results are explained under the assumption that the position of the Fermi level Ef at GBs depends on the degree of occupancy of defect states at the GBs, while Ef approached the bottom of the conduction band or the top of the valence band in the BaSi2 grain interiors with increasing impurity concentrations. In both cases, such small barrier heights may not deteriorate the carrier transport properties. The electronic structures of impurity-doped BaSi2 are also discussed using first-principles pseudopotential method to discuss the insertion sites of impurity atoms and clarify the reason for the observed n-type conduction in the Sb-doped BaSi2 and p-type conduction in the B-doped BaSi2.
Room temperature magnetoelectric coupling in Zn1−xCoxO/BaTiO3 bilayer system
Authors: Sundararaj Anuraj , Annal Therese Helen , Ramaswamy Shivaraman , Chandrasekaran Gopalakrishnan , Annamalai Karthigeyan
Published: September 2014

We report on room temperature magnetoelectric coupling in Zn1−xCoxO/BaTiO3 (x = 0.02, 0.05, and 0.10) bilayer thinfilm multiferroic system (BLS) grown on SrTiO3 (100) substrate. All the BLSs exhibit room temperature ferroelectric response. The BLS with x = 0.02 is paramagnetic, while the BLS with x = 0.05 and 0.10 is weakly ferromagnetic. Increase in Co concentration of the BLS results in reduction of permittivity and electric polarization along with increase of coercive voltage, coercive field, and magnetic moment. The d33 value change from 23 pm/V to 30 pm/V with increase in external magnetic field from 1500 G to 2500 G for BLS with x = 0.05. This shows that Zn1−xCoxO/BaTiO3 is magnetoelectrically coupled at room temperature.
Atomistic simulation of Er irradiation induced defects in GaN nanowires
Authors: Ullah M. W. , Kuronen A. , Stukowski A. , Djurabekova F. , Nordlund K.
Published: September 2014

Classical molecular dynamics simulation was used to irradiate a GaN nanowire with rear-earth erbium (Er). Ten cumulative irradiations were done using an ion energy of 37.5 keV on a 10 × 10 nm2 surface area which corresponds to a fluence of 1 × 1013 cm−2. We studied the location and types of defects produced in the irradiation. Er implantation leads to a net positive (expansion) strain in the nanowire and especially at the top region a clear expansion has been observed in the lateral and axial directions. The lattice expansion is due to the hydrostatic strain imposed by a large number of radiation induced defects at the top of the NW. Due to the large surface-to-volume ratio, most of the defects were concentrated at the surface region, which suggests that the experimentally observed yellow luminescence (YL) in ion implanted GaN NWs arises from surface defects. We observed big clusters of point defects and vacancy clusters which are correlated with stable lattice strain and the YL band, respectively.
Scaling laws of cumulative thermal conductivity for short and long phonon mean free paths
Authors: Aketo Daisuke , Shiga Takuma , Shiomi Junichiro
Published: September 2014

Cumulative thermal conductivity (CTC), an accumulation function of lattice thermal conductivity with respect to the phonon mean free path (PMFP), is a useful single-crystal property to gain insight into how much nanostructuring can potentially reduce thermal conductivity. While the details of the CTC profile depend on each material, we have identified that the profile has universal features in the short and long PMFP regimes with each characteristic length scale. In each PMFP regime, by scaling the PMFP with the characteristic length derived using phenomenological models, CTC calculated based on first principles for various materials collapse on a master curve. We also find an empirical relation between the short and long PMFP characteristic length scales, which allows us to roughly estimate the onset/offset PMFP of CTC (i.e., PMFP when CTC are 10%/90% of the total thermal conductivity) only with the knowledge of bulk thermal conductivity and averaged group velocity. The finding provides a facile way to estimate the range of PMFP with noticeable contribution to lattice thermal conductivity, which is useful for designing nanostructured materials with low thermal conductivity, particularly in developing thermoelectric materials.
Control of waveguide properties by tuning femtosecond laser induced compositional changes
Authors: del Hoyo Jesús , Vazquez Rebeca Martinez , Sotillo Belén , Fernandez Toney Teddy , Siegel Jan , Fernández Paloma , Osellame Roberto , Solis Javier
Published: September 2014

Local compositional changes induced by high repetition rate fs-laser irradiation can be used to produce high performance optical waveguides in phosphate-based glasses. The waveguide refractive index contrast is determined by the local concentration of La, which can be changed by the action of the writing laser pulses. In this work, we have investigated the degree of control that can be exerted using this waveguide writing mechanism over the cross-section of the guiding region, and the local refractive index and compositional changes induced. These variables can be smoothly controlled via processing parameters using the slit shaping technique with moderate Numerical Aperture (NA 0.68) writing optics. The combined use of X-ray microanalysis and near field refractive index profilometry evidences a neat linear correlation between local La content and refractive index increase over a broad Δn interval (>3 × 10−2). This result further confirms the feasibility of generating efficient, integrated optics elements via spatially selective modification of the glass composition.
Room temperature photoluminescence from InxAl(1−x)N films deposited by plasma-assisted molecular beam epitaxy
Authors: Kong W. , Mohanta A. , Roberts A. T. , Jiao W. Y. , Fournelle J. , Kim T. H. , Losurdo M. , Everitt H. O. , Brown A. S.
Published: September 2014

InAlN films deposited by plasma-assisted molecular beam epitaxy exhibited a lateral composition modulation characterized by 10–12 nm diameter, honeycomb-shaped, columnar domains with Al-rich cores and In-rich boundaries. To ascertain the effect of this microstructure on its optical properties, room temperature absorption and photoluminescence characteristics of InxAl(1−x)N were comparatively investigated for indium compositions ranging from x = 0.092 to 0.235, including x = 0.166 lattice matched to GaN. The Stokes shift of the emission was significantly greater than reported for films grown by metalorganic chemical vapor deposition, possibly due to the phase separation in these nanocolumnar domains. The room temperature photoluminescence also provided evidence of carrier transfer from the InAlN film to the GaN template.
Multi-focus parallel detection of fluorescent molecules at picomolar concentration with photonic nanojets arrays
Authors: Ghenuche Petru , de Torres Juan , Ferrand Patrick , Wenger Jérôme
Published: September 2014

Fluorescence sensing and fluorescence correlation spectroscopy (FCS) are powerful methods to detect and characterize single molecules; yet, their use has been restricted by expensive and complex optical apparatus. Here, we present a simple integrated design using a self-assembled bi-dimensional array of microspheres to realize multi-focus parallel detection scheme for FCS. We simultaneously illuminate and collect the fluorescence from several tens of microspheres, which all generate their own photonic nanojet to efficiently excite the molecules and collect the fluorescence emission. Each photonic nanojet contributes to the global detection volume, reaching FCS detection volumes of several tens of femtoliters while preserving the fluorescence excitation and collection efficiencies. The microspheres photonic nanojets array enables FCS experiments at low picomolar concentrations with a drastic reduction in apparatus cost and alignment constraints, ideal for microfluidic chip integration.
Localization and magnetism of the resonant impurity states in Ti doped PbTe
Authors: Wiendlocha Bartlomiej
Published: September 2014

The problem of localization of the resonant impurity states is discussed for an illustrative example of Titanium doped Lead Telluride. Electronic structure of PbTe:Ti is studied using first principles methods, densities of states, and Bloch spectral functions are analyzed. We show that Ti creates resonant states in the conduction band of PbTe, however, spectral functions of the system strongly suggest localization of these states and show poor hybridization with PbTe electronic structure. The contrast between results presented here and previously reported spectral functions for PbTe:Tl correlate very well with the different effect of those impurities on thermopower (S) of PbTe, which is large increase is S for PbTe:Tl and almost no effect on S for PbTe:Ti. Moreover, magnetic properties of the system are studied and formation of magnetic moments on Ti atoms is found, both for ordered (ferromagnetic) and disordered (paramagnetic-like) phases, showing that PbTe:Ti can be a magnetic semiconductor.
Density of trap states in a polymer field-effect transistor
Authors: Kim Seohee , Ha Tae-Jun , Sonar Prashant , Dodabalapur Ananth
Published: September 2014

We report a more accurate method to determine the density of trap states in a polymer field-effect transistor. In the approach, we describe in this letter, we take into consideration the sub-threshold behavior in the calculation of the density of trap states. This is very important since the sub-threshold regime of operation extends to fairly large gate voltages in these disordered semiconductor based transistors. We employ the sub-threshold drift-limited mobility model (for sub-threshold response) and the conventional linear mobility model for above threshold response. The combined use of these two models allows us to extract the density of states from charge transport data much more accurately. We demonstrate our approach by analyzing data from diketopyrrolopyrrole based co-polymer transistors with high mobility. This approach will also work well for other disordered semiconductors in which sub-threshold conduction is important.
Comparison between feeding rumen-protected choline and vitamin E on milk yield and blood metabolites in early lactation dairy cows
Authors: Rahmani Mohammadreza , Dehghan-banadaky Mehdi , Kamalyan Romic
Published: September 2014

Twenty-four early-lactation primiparous and multiparous Holstein cows, beginning 5 weeks postpartum, were used for 4 weeks to investigate the effects of feeding rumen-protected choline (RPC) or vitamin E on milk yield, dry matter intake (DMI), blood metabolites and plasma enzymes. Cows were randomly assigned to one of the following treatments: no supplement (control), 90 g/day of RPC, or 4400 IU/day of vitamin E. Treatments did not affect milk yield, DMI, plasma glucose, non-esterified fatty acids, blood urea nitrogen, aspartate aminotransferase or total bilirubin, whereas feeding RPC affected cholesterol, plasma albumin, and alkaline phosphatase (ALP). Feeding vitamin E affected triglyceride, cholesterol, β-hydroxy butyric acid, gamma-glutamyl transferase and alanine aminotransferase, and highly affected plasma albumin and ALP. There was a tendency for vitamin E supplementation to increase plasma total protein concentration. The results of this study suggest that supplemental vitamin E may improve liver function in dairy cows in early lactation.
Strategies to increase the yield and yield stability of crops under drought – are we making progress?
Authors: Turner Neil C. , Blum Abraham , Cakir Mehmet , Steduto Pasquale , Tuberosa Roberto , Young Neil
Published: September 2014

The objective of the InterDrought conferences is to be a platform for debating key issues that are relevant for increasing the yield and yield stability of crops under drought via integrated approaches. InterDrought-IV, held in Perth, Australia, in September 2013, followed previous InterDrought conferences in bringing together researchers in agronomy, soil science, modelling, physiology, biochemistry, molecular biology, genetics and plant breeding. Key themes were (i) maximising water productivity; (ii) maximising dryland crop production; (iii) adaptation to water-limited environments; (iv) plant productivity under drought through effective water capture, improved transpiration efficiency, and growth and yield; and (v) breeding for water-limited environments through variety development, and trait-based genomics-assisted and transgenic approaches. This paper highlights some key issues and presents recommendations for future action. Improved agronomic interventions were recognised as being important contributors to improved dryland crop yields in water-limited environments, and new methods for exploring root architecture and water capture were highlighted. The increase in crop yields under drought through breeding and selection, the development of high-throughput phenotyping facilities for field-grown and pot-grown plants, and advances in understanding the molecular basis of plant responses and resistance to drought stress were recognised. Managed environment phenotyping facilities, a range of field environments, modelling, and genomic molecular tools are being used to select and release drought-resistant cultivars of all major crops. Delegates discussed how individuals and small teams can contribute to progress, and concluded that interdisciplinary research, linkages to international agricultural research centres, public–private partnerships and continuation of the InterDrought conferences will be instrumental for progress.
Changes in myometrial expression of progesterone receptor membrane components 1 and 2 are associated with human parturition at term
Authors: Wang Ray , Sheehan Penelope M. , Brennecke Shaun P.
Published: September 2014

While the exact mechanism of human parturition remains unknown, functional progesterone withdrawal is believed to play a key regulatory role. Progesterone receptor membrane components 1 and 2 (PGRMC1, PGRMC2) are putative progesterone receptors and the aim of this project was to investigate their expression in human myometrium. Human term myometrium was obtained from the lower uterine segment incision in women undergoing elective (not-in-labour, NIL; n = 11) and emergency Caesarean sections (in-labour, IL; n = 10), following written consent. PGRMC1 and 2 expression was quantified using real-time reverse transcription polymerase chain reaction and western blot. Subcellular localisation was performed by immunohistochemistry and immunofluorescence. There was a significant decrease in PGRMC1 mRNA (P = 0.0317) and protein expression (P = 0.0151) in IL myometrium, compared with NIL myometrium. PGRMC2 mRNA expression (P = 0.0151) was also decreased in IL myometrium, compared with NIL myometrium. Immunostaining studies confirmed the presence of PGRMC1 and 2 in smooth-muscle cells. Expression was perinuclear in NIL myometrium and more generalised and cytoplasmic in IL myometrium. The decrease in PGRMC1 expression and the translocation away from a perinuclear location for both PGRMC1 and 2 could contribute to a functional progesterone withdrawal that may ultimately initiate parturition.
Antigen affinity and antigen dose exert distinct influences on CD4 T-cell differentiation
Authors: Keck Simone , Schmaler Mathias , Ganter Stefan , Wyss Lena , Oberle Susanne , Huseby Eric S. , Zehn Dietmar , King Carolyn G.
Published: September 2014

Significance

T-cell receptor recognition of antigen is an essential first step in the initiation of a T-cell response. This report demonstrates that CD4 T cells responding during an infection can discriminate between antigen affinity and antigen dose, resulting in distinct types of effector and memory cell generation. Moreover, memory T cells “remember” the strength of primary T-cell activation and maintain a biased recall response upon secondary infection. These data reveal that antigen affinity exerts an important influence on T-cell differentiation that is not compensated for by high antigen dose. Understanding the rules of CD4 T-cell differentiation is integral to effective vaccine design.
Hybrid polarizing solids for pure hyperpolarized liquids through dissolution dynamic nuclear polarization
Authors: Gajan David , Bornet Aurélien , Vuichoud Basile , Milani Jonas , Melzi Roberto , van Kalkeren Henri A. , Veyre Laurent , Thieuleux Chloé , Conley Matthew P. , Grüning Wolfram R. , Schwarzwälder Martin , Lesage Anne , Copéret Christophe , Bodenhausen Geoffrey , Emsley Lyndon , Jannin Sami
Published: September 2014

Significance

Hyperpolarization by dissolution dynamic nuclear polarization can dramatically enhance signal intensities in MRI and NMR, notably for metabolic tracers for imaging and diagnosis. It is applicable to a variety of substrates for in vivo imaging and chemistry but requires the use of contaminants (glassing agents and free radicals) that may interact with cells and proteins and can have potential side effects. These contaminants can sometimes be eliminated by precipitation followed by filtration or solvent extraction, but these methods are substrate-specific, are usually time-consuming, and typically result in signal loss. Here, production of pure hyperpolarized liquids free of contaminants is shown by a simple wetting–polarization–filtration sequence for a solid silica matrix containing homogeneously distributed persistent radicals.
Single nanoparticle detection using split-mode microcavity Raman lasers
Authors: Li Bei-Bei , Clements William R. , Yu Xiao-Chong , Shi Kebin , Gong Qihuang , Xiao Yun-Feng
Published: September 2014

Significance

Optical sensing with ultrahigh sensitivity of single nanoscale objects is strongly desirable for applications in various fields, such as in early-stage diagnosis of human diseases and in environmental monitoring, as well as in homeland security. In this article, we report an optical technique for single nanoparticle detection in both air and an aqueous environment, with an ultralow detection limit.
ICAM-1 as a molecular target for triple negative breast cancer
Authors: Guo Peng , Huang Jing , Wang Liya , Jia Di , Yang Jiang , Dillon Deborah A. , Zurakowski David , Mao Hui , Moses Marsha A. , Auguste Debra T.
Published: September 2014

Significance

Triple negative breast cancers (TNBCs) have a poor prognosis (5-y survival of 74.5%) among all breast cancer patients (5-y survival of greater than 95%) because of the aggressiveness of the disease and the lack of targeted therapeutics. We show that intercellular adhesion molecule-1 (ICAM-1) is differentially expressed in human TNBC tumor tissues by immunohistochemistry and in human TNBC cell lines via quantification of gene and protein expression. Iron oxide nanoparticles functionalized with ICAM-1 antibody (ICAM-IONP) were synthesized as MRI probes. An in vivo signal enhancement of 2.6-fold for ICAM-IONPs was measured relative to controls, demonstrating that ICAM-1 is a potential diagnostic and therapeutic target for TNBC treatment.
Entrained neural oscillations in multiple frequency bands comodulate behavior
Authors: Henry Molly J. , Herrmann Björn , Obleser Jonas
Published: September 2014

Significance

Our sensory environment is teeming with complex rhythmic structure, but how do environmental rhythms (such as those present in speech or music) affect our perception? In a human electroencephalography study, we investigated how auditory perception is affected when brain rhythms (neural oscillations) synchronize with the complex rhythmic structure in synthetic sounds that possess rhythmic characteristics similar to speech. We found that neural phase in multiple frequency bands synchronized with the complex stimulus rhythm and interacted to determine target-detection performance. Critically, the influence of neural oscillations on target-detection performance was present only for frequency bands synchronized with the rhythmic structure of the stimuli. Our results elucidate how multiple frequency bands shape the effective neural processing of environmental stimuli.