bluuebunny/crossref_metadata_2025 huggingface dataset:
Discovery of small molecule inhibitors targeting the SUMO–SIM interaction using a protein interface consensus approach
Authors: Voet Arnout R. D. , Ito Akihiro , Hirohama Mikako , Matsuoka Seiji , Tochio Naoya , Kigawa Takanori , Yoshida Minoru , Zhang Kam Y. J.
Published: March 2014

We present a virtual screening approach incorporating the consensus of protein interactions that led to the discovery of non-peptidic inhibitors.
Photocatalytic degradation of the antibiotic levofloxacin using highly crystalline TiO2 nanoparticles
Authors: Kansal Sushil Kumar , Kundu Pranati , Sood Swati , Lamba Randeep , Umar Ahmad , Mehta S. K.
Published: March 2014

Highly crystalline TiO2 (anatase) nanoparticles were synthesized by a facile sol–gel method for the photocatalytic degradation and inhibition of the commonly used antibiotic drug, levofloxacin.
Microwave-assisted one-pot synthesis and anti-biofilm activity of 2-amino-1H-imidazole/triazole conjugates
Authors: Steenackers Hans , Ermolat'ev Denis , Trang Tran Thi Thu , Savalia Bharat , Sharma Upendra K. , De Weerdt Ami , Shah Anamik , Vanderleyden Jozef , Van der Eycken Erik V.
Published: March 2014

A microwave-assisted protocol was developed for the construction of 2-amino-1H-imidazole/triazole conjugates with anti-biofilm activity.
The self-assembly of shape controlled functionalized graphene–MnO2 composites for application as supercapacitors
Authors: Feng Xiaomiao , Chen Ningna , Zhang Yu , Yan Zhenzhen , Liu Xingfen , Ma Yanwen , Shen Qingming , Wang Lianhui , Huang Wei
Published: March 2014

Shape controlled functionalized graphene–MnO2 composites with high capacitive performance can be obtained by self-assembly.
Extremely high color rendering white light from surface passivated carbon dots and Zn-doped AgInS2 nanocrystals
Authors: Chung Wonkeun , Jung Hyunchul , Lee Chang Hun , Kim Sung Hyun
Published: March 2014

In this study, highly luminescent carbon dots with diameters of 3–5 nm were synthesized via the carbonization of citric acid, and the effects of surface passivation and carbonization temperature on the optical properties were investigated.
An off-the-shelf sensing system for physiological phosphates
Authors: Mallet Alie M. , Liu Yuanli , Bonizzoni Marco
Published: March 2014

An off-the-shelf supramolecular sensing system was designed to discriminate biologically relevant phosphates in neutral water using multivariate data analysis.
Bulky toroidal and vesicular self-assembled nanostructures from fullerene end-capped rod-like polymers
Authors: Mazzier D. , Mba M. , Zerbetto M. , Moretto A.
Published: March 2014

In this work, we present novel fullerene (C60) end-capped rod-like polypeptide-polymers, obtained by one-pot thiol–ene chemistry.
Effect of water on the transport properties of protic and aprotic imidazolium ionic liquids – an analysis of self-diffusivity, conductivity, and proton exchange mechanism
Authors: Yaghini N. , Nordstierna L. , Martinelli A.
Published: March 2014

We investigate the effect of water on the transport properties of protic and aprotic ionic liquids of imidazolium.
Aromaticity in transition structures
Authors: Schleyer Paul von Ragué , Wu Judy I. , Cossío Fernando P. , Fernández Israel
Published: March 2014

This tutorial review presents interpretative computational tools to describe and quantify the different manifestations of aromaticity in transition structures.
City block distance and rough-fuzzy clustering for identification of co-expressed microRNAs
Authors: Paul Sushmita , Maji Pradipta
Published: March 2014

The microRNAs or miRNAs are short, endogenous RNAs having ability to regulate mRNA expression at the post-transcriptional level.
A cyclization–carbonylation–cyclization coupling reaction of (ortho-alkynyl phenyl) (methoxymethyl) sulfides with the palladium(ii)-bisoxazoline catalyst
Authors: Jiang Yiyun , Kusakabe Taichi , Takahashi Keisuke , Kato Keisuke
Published: March 2014

A CCC-coupling reaction of (o-alkynylphenyl) (methoxymethyl) sulfides, catalyzed by (box)PdII complexes, afforded symmetrical ketones bearing two benzo[b]thiophene groups in good to excellent yields.
Total synthesis of monosporascone and dihydromonosporascone
Authors: Punch Kathryn A. , Piggott Matthew J.
Published: March 2014

The first synthesis of monosporascone has been achieved in five steps and 57% overall yield.
Removal characteristics of organics and nitrogen in a novel four-stage biofilm integrated system for enhanced treatment of coking wastewater under different HRTs
Authors: Zhou Xin , Li Yaxin , Zhao Yi
Published: March 2014

Coking wastewater contains substantial organics and nitrogen, posing a great threat to the water environment.
Production of few-layer MoS2nanosheets through exfoliation of liquid N2–quenched bulk MoS2
Authors: Van Thanh Dang , Pan Chien-Chung , Chu Chih-Wei , Wei Kung-Hwa
Published: March 2014

An efficient method for the production of few-layer MoS2nanosheets through exfoliation of bulk MoS2compounds that were subject to quenching in liquid N2and subsequent ultrasonication.
Polyorthotoluidine dispersed castor oil polyurethane anticorrosive nanocomposite coatings
Authors: Kashif Mohammad , Ahmad Sharif
Published: March 2014

Conducting polymer (polyorthotoluidine) dispersed castor oil polyurethane nanocomposite coatings were synthesized and show a remarkably higher corrosion resistant performance in alkaline medium.
Nanosheet-assembled 3D nanoflowers of ruthenium oxide with superior rate performance for supercapacitor applications
Authors: Kim Ji-Young , Kim Kwang-Heon , Kim Hyun-Kyung , Park Sang-Hoon , Chung Kyung Yoon , Kim Kwang-Bum
Published: March 2014

Novel ruthenium oxide nanostructures are synthesized via a microwave-hydrothermal process. An electrode based on the 3D nanoflowers exhibits high specific capacitance and superior rate capability, resulting from the hierarchical 3D porous nanostructures.
Full factorial design applied to the synthesis of Pd–Ag nanobars by the polyol method and the perspective for ethanol oxidation
Authors: Carrera-Cerritos R. , Ponce de León C. , Ledesma-García J. , Fuentes-Ramírez R. , Arriaga L. G.
Published: March 2014

Full factorial design methodology was applied for the first time to the synthesis and optimization of palladium–silver nanobars using the polyol process as reducer.
A one-step strategy for cross-linkable aliphatic polycarbonates with high degradability derived from CO2, propylene oxide and itaconic anhydride
Authors: Song Pengfei , Mao Xudong , Zhang Xuefeng , Zhu Xiaogang , Wang Rongmin
Published: March 2014

A one-step strategy for the preparation of cross-linkable aliphatic polycarbonates via the direct terpolymerization of CO2, propylene oxide and itaconic anhydride is presented for the first time in this paper.
High catalytic performance and sustainability of the Ni/La2O3 catalyst for daily pre-reforming of liquefied petroleum gas under a low steam/carbon molar ratio
Authors: Huang Zhen , Wang Xueguang , Wang Zhiying , Zou Xiujing , Ding Weizhong , Lu Xionggang
Published: March 2014

The Ni/La2O3 catalyst shows high activity and excellent sustainability for daily pre-reforming of liquefied petroleum gas under a low steam/carbon molar ratio.
Facile synthesis and superior electrochemical performances of CoNi2S4/graphene nanocomposite suitable for supercapacitor electrodes
Authors: Du Weimin , Wang Zhiyong , Zhu Zhaoqiang , Hu Sen , Zhu Xiaoyan , Shi Yunfeng , Pang Huan , Qian Xuefeng
Published: March 2014

CoNi2S4/graphene nanocomposite electrodes exhibit excellent pseudocapacitance behavior enhanced by synergistic effect, demonstrating the nanocomposite's promise as an electrode material for high-performance supercapacitors.
Luminescence modulation in liquid crystalline phases containing a dispiro[fluorene-9,11′-indeno[1,2-b]fluorene-12′,9′′-fluorene] core
Authors: Thiery Sébastien , Heinrich Benoît , Donnio Bertrand , Poriel Cyril , Camerel Franck
Published: March 2014

Luminescence modulations of a bulky dispiro[fluorene-9,11′-indeno[1,2-b]fluorene-12′,9′′-fluorene] (DSF-IF) core embedded in thermotropic liquid crystal phases.
Reduced efficiency roll-off in light-emitting diodes enabled by quantum dot–conducting polymer nanohybrids
Authors: Bae Wan Ki , Lim Jaehoon , Zorn Matthias , Kwak Jeonghun , Park Young-Shin , Lee Donggu , Lee Seonghoon , Char Kookheon , Zentel Rudolf , Lee Changhee
Published: March 2014

Hybridization of colloidal quantum-dots and conducting polymers improves the efficiency roll-off of quantum-dot light-emitting diodes.
Impact of fluorine based reactive chemistry on structure and properties of high moment magnetic material
Authors: Yang Xiaoyu , Chen Lifan , Han Hongmei , Fu Lianfeng , Sun Ming , Liu Feng , Zhang Jinqiu
Published: March 2014

The impact of the fluorine-based reactive ion etch (RIE) process on the structural, electrical, and magnetic properties of NiFe and CoNiFe-plated materials was investigated. Several techniques, including X-ray fluorescence, 4-point-probe, BH looper, transmission electron microscopy (TEM), and electron energy loss spectroscopy (EELS), were utilized to characterize both bulk film properties such as thickness, average composition, Rs, ρ, Bs, Ms, and surface magnetic “dead” layers' properties such as thickness and element concentration. Experimental data showed that the majority of Rs and Bs changes of these bulk films were due to thickness reduction during exposure to the RIE process. ρ and Ms change after taking thickness reduction into account were negligible. The composition of the bulk films, which were not sensitive to surface magnetic dead layers with nano-meter scale, showed minimum change as well. It was found by TEM and EELS analysis that although both before and after RIE there were magnetic dead layers on the top surface of these materials, the thickness and element concentration of the layers were quite different. Prior to RIE, dead layer was actually native oxidation layers (about 2 nm thick), while after RIE dead layer consisted of two sub-layers that were about 6 nm thick in total. Sub-layer on the top was native oxidation layer, while the bottom layer was RIE “damaged” layer with very high fluorine concentration. Two in-situ RIE approaches were also proposed and tested to remove such damaged sub-layers.
Communication: Anomalous temperature dependence of the intermediate range order in phosphonium ionic liquids
Authors: Hettige Jeevapani J. , Kashyap Hemant K. , Margulis Claudio J.
Published: March 2014

In a recent article by the Castner and Margulis groups [Faraday Discuss. 154, 133 (2012)], we described in detail the structure of the tetradecyltrihexylphosphonium bis(trifluoromethylsulfonyl)-amide ionic liquid as a function of temperature using X-ray scattering, and theoretical partitions of the computationally derived structure function. Interestingly, and as opposed to the case in most other ionic-liquids, the first sharp diffraction peak or prepeak appears to increase in intensity as temperature is increased. This phenomenon is counter intuitive as one would expect that intermediate range order fades as temperature increases. This Communication shows that a loss of hydrophobic tail organization at higher temperatures is counterbalanced by better organization of polar components giving rise to the increase in intensity of the prepeak.
Molecular dynamics simulations of the nucleation of water: Determining the sticking probability and formation energy of a cluster
Authors: Tanaka Kyoko K. , Kawano Akio , Tanaka Hidekazu
Published: March 2014

We performed molecular dynamics simulations of the nucleation of water vapor in order to test nucleation theories. Simulations were performed for a wide range of supersaturation ratios (S = 3–25) and water temperatures (Tw = 300–390 K). We obtained the nucleation rates and the formation free energies of a subcritical cluster from the cluster size distribution. The classical nucleation theory and the modified classical nucleation theory (MCNT) overestimate the nucleation rates in all cases. The semi-phenomenological model, which corrects the MCNT prediction using the second virial coefficient of a vapor, reproduces the formation free energy of a cluster with the size ≲20 to within 10% and the nucleation rate and cluster size distributions to within one order of magnitude. The sticking probability of the vapor molecules to the clusters was also determined from the growth rates of the clusters. The sticking probability rapidly increases with the supersaturation ratio S, which is similar to the Lennard-Jones system.
Uniform electron gases. II. The generalized local density approximation in one dimension
Authors: Loos Pierre-François , Ball Caleb J. , Gill Peter M. W.
Published: March 2014

We introduce a generalization (gLDA) of the traditional Local Density Approximation (LDA) within density functional theory. The gLDA uses both the one-electron Seitz radius rs and a two-electron hole curvature parameter η at each point in space. The gLDA reduces to the LDA when applied to the infinite homogeneous electron gas but, unlike the LDA, it is also exact for finite uniform electron gases on spheres. We present an explicit gLDA functional for the correlation energy of electrons that are confined to a one-dimensional space and compare its accuracy with LDA, second- and third-order Møller-Plesset perturbation energies, and exact calculations for a variety of inhomogeneous systems.
Effects of the interplay between atomic and magnetic order on the properties of metamagnetic Ni-Co-Mn-Ga shape memory alloys
Authors: Seguí C.
Published: March 2014

Ni-Co-Mn-Ga ferromagnetic shape memory alloys show metamagnetic behavior for a range of Co contents. The temperatures of the structural and magnetic transitions depend strongly on composition and atomic order degree, in such a way that combined composition and thermal treatment allows obtaining martensitic transformation between any magnetic state of austenite and martensite. This work presents a detailed analysis of the effect of atomic order on Ni-Co-Mn-Ga alloys through the evolution of structural and magnetic transitions after quench from high temperatures and during post-quest ageing. It is found that the way in which the atomic order affects the martensitic transformation temperatures and entropy depends on the magnetic order of austenite and martensite. The results can be explained assuming that improvement of atomic order decreases the free energy of the structural phases according to their magnetic order. However, it is assumed in this work that changes in the slope—that is, the entropy—of the Gibbs free energy curves are also decisive to the stability of the two-phase system. The experimental transformation entropy values have been compared with a phenomenological model, based on a Bragg–Williams approximation, accounting for the magnetic contribution. The excellent agreement obtained corroborates the magnetic origin of changes in transformation entropy brought about by atomic ordering.
Non-orthogonal configuration interaction for the calculation of multielectron excited states
Authors: Sundstrom Eric J. , Head-Gordon Martin
Published: March 2014

We apply Non-orthogonal Configuration Interaction (NOCI) to molecular systems where multielectron excitations, in this case double excitations, play a substantial role: the linear polyenes and β-carotene. We demonstrate that NOCI when applied to systems with extended conjugation, provides a qualitatively correct wavefunction at a fraction of the cost of many other multireference treatments. We also present a new extension to this method allowing for purification of higher-order spin states by utilizing Generalized Hartree-Fock Slater determinants and the details for computing ⟨S2⟩ for the ground and excited states.
Intrinsic nature of visible-light absorption in amorphous semiconducting oxides
Authors: Kang Youngho , Song Hochul , Nahm Ho-Hyun , Jeon Sang Ho , Cho Youngmi , Han Seungwu
Published: March 2014

To enlighten microscopic origin of visible-light absorption in transparent amorphous semiconducting oxides, the intrinsic optical property of amorphous InGaZnO4 is investigated by considering dipole transitions within the quasiparticle band structure. In comparison with the crystalline InGaZnO4 with the optical gap of 3.6 eV, the amorphous InGaZnO4 has two distinct features developed in the band structure that contribute to significant visible-light absorption. First, the conduction bands are down-shifted by 0.55 eV mainly due to the undercoordinated In atoms, reducing the optical gap between extended states to 2.8 eV. Second, tail states formed by localized oxygen p orbitals are distributed over ∼0.5 eV near the valence edge, which give rise to substantial subgap absorption. The fundamental understanding on the optical property of amorphous semiconducting oxides based on underlying electronic structure will pave the way for resolving instability issues in recent display devices incorporating the semiconducting oxides.
First-principle calculation and assignment for vibrational spectra of Ba(Mg1/3Nb2/3)O3 microwave dielectric ceramic
Authors: Diao Chuan-Ling , Wang Chun-Hai , Luo Neng-Neng , Qi Ze-Ming , Shao Tao , Wang Yu-Yin , Lu Jing , Wang Quan-Chao , Kuang Xiao-Jun , Fang Liang , Shi Feng , Jing Xi-Ping
Published: March 2014

1:2 B-site cation ordered Ba(Mg1/3Nb2/3)O3 ceramic was synthesized using conventional solid-state reaction at 1600 °C for 12 h. The structure parameters were obtained through Rietveld refinement of X-ray diffraction data. The Raman peak frequencies were obtained by Lorenz fitting on Raman spectrum. Four-parameter semiquantum model was used to fit the infrared (IR) reflectivity spectrum, and the fitted parameters were used to calculate the dielectric permittivity ε and dielectric loss tanδ. A total of 9 active Raman and 16 active IR modes were obtained using first-principle calculations based on density functional theory with local density approximation. All of the vibrational modes were assigned and represented by linear combinations of the symmetry coordinates deduced using group theory analysis. The Raman mode with the highest frequency A1g(4) (789 cm−1) can be described as the breathing vibration of NbO6. The IR modes Eu(1) (149 cm−1) and A2u(2) (212 cm−1), which can be described as the twisting vibrations of Ba–MgO6/Ba–NbO6 on the a–b plane and the stretching vibrations of Ba–MgO6/Ba–NbO6 along the c direction, respectively, are the dominant contributing modes to ε and tanδ. The dielectric property parameters obtained using IR spectrum fittings, first-principal calculations, and microwave measurements were compared.
Characterizing system dynamics with a weighted and directed network constructed from time series data
Authors: Sun Xiaoran , Small Michael , Zhao Yi , Xue Xiaoping
Published: March 2014

In this work, we propose a novel method to transform a time series into a weighted and directed network. For a given time series, we first generate a set of segments via a sliding window, and then use a doubly symbolic scheme to characterize every windowed segment by combining absolute amplitude information with an ordinal pattern characterization. Based on this construction, a network can be directly constructed from the given time series: segments corresponding to different symbol-pairs are mapped to network nodes and the temporal succession between nodes is represented by directed links. With this conversion, dynamics underlying the time series has been encoded into the network structure. We illustrate the potential of our networks with a well-studied dynamical model as a benchmark example. Results show that network measures for characterizing global properties can detect the dynamical transitions in the underlying system. Moreover, we employ a random walk algorithm to sample loops in our networks, and find that time series with different dynamics exhibits distinct cycle structure. That is, the relative prevalence of loops with different lengths can be used to identify the underlying dynamics.
Fermi level depinning and contact resistivity reduction using a reduced titania interlayer in n-silicon metal-insulator-semiconductor ohmic contacts
Authors: Agrawal Ashish , Lin Joyce , Barth Michael , White Ryan , Zheng Bo , Chopra Saurabh , Gupta Shashank , Wang Ke , Gelatos Jerry , Mohney Suzanne E. , Datta Suman
Published: March 2014

Experimental evidence of reduction of ultrathin TiO2 by Ti is presented and its effect on Fermi level depinning and contact resistivity reduction to Si is experimentally studied. A low effective barrier height of 0.15 V was measured with a Ti/10 Å TiO2−x/n-Si MIS device, indicating 55% reduction compared to a metal/n-Si control contact. Ultra-low contact resistivity of 9.1 × 10−9 Ω-cm2 was obtained using Ti/10 Å TiO2−x/n+ Si, which is a dramatic 13X reduction from conventional unannealed contacts on heavily doped Si. Transport through the MIS device incorporating the effect of barrier height reduction and insulator conductivity as a function of insulator thickness is comprehensively analyzed and correlated with change in contact resistivity. Low effective barrier height, high substrate doping, and high conductivity interfacial layer are identified as key requirements to obtain low contact resistivity using MIS contacts.
Multilayer magnetostrictive structure based surface acoustic wave devices
Authors: Zhou H. , Talbi A. , Tiercelin N. , Bou Matar O.
Published: March 2014

This study addresses the experimental and theoretical investigations of guided elastic waves propagation in piezo-magnetic multi-layered structure. The structure is composed of a 20×TbCo2(5nm)/FeCo(5nm) nanostructured multi-layer deposited between two Aluminum (Al) Inter-Digitals Transducers forming a surface acoustic wave delay line, on a Y-cut LiNbO3 substrate. We compare the calculated and measured phase velocity variation under the action of the external magnetic field orientation and magnitude. We find quantitative agreement between the measured and modeled phase velocity shift for all external magnetic field configurations (hard axis and easy axis) and for different shape modes of elastic waves at their first and third harmonic operation frequencies. The shear horizontal mode exhibits a maximum phase velocity shift close to 20% for a ratio close to 1 between magneto-elastic film thickness and wavelength.
On the mobility and contact resistance evaluation for transistors based on MoS2 or two-dimensional semiconducting atomic crystals
Authors: Chang Hsiao-Yu , Zhu Weinan , Akinwande Deji
Published: March 2014

Contact resistance (Rc) can substantially obscure the extracted mobility based on standard transconductance or two-point conductance measurements of field-effect devices especially for low density of states materials such as MoS2 or similar atomic crystals. Currently, there exists a pressing need for a routine technique that can decouple mobility extraction from Rc. By combining experiments and analysis, we show that the Y-function method offers a robust route for evaluating the low-field mobility, threshold voltage and Rc even when the contact is a Schottky-barrier as is common in two-dimensional transistors. In addition, an independent modified transfer length method evaluation corroborates the Y-function analysis.
Experimental demonstration of optical real-time data compression
Authors: Asghari Mohammad H. , Jalali Bahram
Published: March 2014

We experimentally demonstrate a method for compressing the time-bandwidth product of analog signals in real-time. By performing self-adaptive stretch, this technology enables digitizers to capture waveforms beyond their bandwidth with digital data size being reduced at the same time. The compression is lossless and is achieved through a transformation of the signal's complex field, performed in the analog domain prior to digitization. For proof of concept experiments, we compress the modulation bandwidth of an optical signal by 500 times. At the same time, we reduce its modulation time-bandwidth product (i.e., the record length) by 2.73 times while achieving 16 dB power efficiency improvement in comparison to the case of using conventional dispersive Fourier transform. Dispersive data compression addresses the big data problem in real-time instruments and in optical communications.
Note: Coupling of multiple laser diodes into a multi-mode fiber
Authors: Ivonyak Y. , Piechal B. , Mrozowicz M. , Bercha A. , Trzeciakowski W.
Published: March 2014

Diode lasers are coupled to a multi-mode fiber (with 100–400 μm core) using a reflector in the form of a regular pyramid. The optimization of the optical setup allows to couple 60%–90% of light into the fiber. The demonstrator achieves 3.5 W in the 100/125 μm fiber with 8 violet (405 nm) diodes, 5.5 W in the 100/125 μm fiber with 8 blue (445 nm) diodes, and 3.3 W in the 200/250 μm fiber with red (638 nm) diodes. The device can work with lasers emitting at many different wavelengths, including green (532 nm) frequency-doubled lasers. Our work was motivated by potential medical applications of these laser sources.
Inkjet-printed stretchable single-walled carbon nanotube electrodes with excellent mechanical properties
Authors: Kim Taehoon , Song Hyunsoo , Ha Jaeheung , Kim Sangwoo , Kim Donghyun , Chung Seungjun , Lee Jaemyon , Hong Yongtaek
Published: March 2014

Inkjet-printed single-walled carbon nanotube (SWCNT) thin films on stretchable substrates were developed, and their electrical properties were investigated. The 1- and 5-layer printed SWCNT thin films had sheet resistances of 169.76 and 19.08 Ω/sq, respectively, and maintained conductive properties under 100% tensile strain. A nitric acid treatment significantly improved the conductivity of the SWCNT electrodes, and after an initial increase, the 5-layer printed SWCNT electrodes showed a normalized resistance of less than 1.2 after 1000 cycles under 100% tensile strain. The potential of the inkjet-printed SWCNT thin films for stretchable electrode applications was demonstrated via integration with a light-emitting diode.
Transmission secondary ion mass spectrometry using 5 MeV C60+ ions
Authors: Nakajima K. , Nagano K. , Suzuki M. , Narumi K. , Saitoh Y. , Hirata K. , Kimura K.
Published: March 2014

In the secondary ion mass spectrometry (SIMS), use of cluster ions has an advantage of producing a high sensitivity of intact large molecular ions over monatomic ions. This paper presents further yield enhancement of the intact biomolecular ions by measuring the secondary ions emitted in the forward direction. Phenylalanine amino acid films deposited on self-supporting thin Si3N4 films were bombarded with 5 MeV C60 ions. Secondary ions emitted in the forward and backward directions were measured. The yield of intact phenylalanine molecular ions emitted in the forward direction is significantly enhanced compared to the backward direction while fragment ions are suppressed. This suggests a large potential of using transmission cluster ion SIMS for the analysis of biological materials.
Hydrostatic pressure to trigger and assist magnetic transitions: Baromagnetic refrigeration
Authors: Quintero M. , Garbarino G. , Leyva A. G.
Published: March 2014

The possible application of the barocaloric effect to produce solid state refrigerators is a topic of interest in the field of applied physics. In this work, we present experimental data about the influence of external pressure on the magnetic properties of a manganite with phase separation. Using the Jahn Teller effect associated with the presence of the charge ordering, we were able to follow the transition to the ferromagnetic state induced by pressure. We also demonstrated that external pressure can assist the ferromagnetic state, decreasing the magnetic field necessary to generate the magnetic transition.
Silicon heterojunction solar cell with passivated hole selective MoOx contact
Authors: Battaglia Corsin , de Nicolás Silvia Martín , De Wolf Stefaan , Yin Xingtian , Zheng Maxwell , Ballif Christophe , Javey Ali
Published: March 2014

We explore substoichiometric molybdenum trioxide (MoOx, x < 3) as a dopant-free, hole-selective contact for silicon solar cells. Using an intrinsic hydrogenated amorphous silicon passivation layer between the oxide and the silicon absorber, we demonstrate a high open-circuit voltage of 711 mV and power conversion efficiency of 18.8%. Due to the wide band gap of MoOx, we observe a substantial gain in photocurrent of 1.9 mA/cm2 in the ultraviolet and visible part of the solar spectrum, when compared to a p-type amorphous silicon emitter of a traditional silicon heterojunction cell. Our results emphasize the strong potential for oxides as carrier selective heterojunction partners to inorganic semiconductors.
Influence of the anodic etching current density on the morphology of the porous SiC layer
Authors: Cao Anh Tuan , Luong Quynh Ngan Truc , Dao Cao Tran
Published: March 2014

In this report, we fabricated a porous layer in amorphous SiC thin films by using constant-current anodic etching in an electrolyte of aqueous diluted hydrofluoric acid. The morphology of the porous amorphous SiC layer changed as the anodic current density changed: At low current density, the porous layer had a low pore density and consisted of small pores that branched downward. At moderate current density, the pore size and depth increased, and the pores grew perpendicular to the surface, creating a columnar pore structure. At high current density, the porous structure remained perpendicular, the pore size increased, and the pore depth decreased. We explained the changes in pore size and depth at high current density by the growth of a silicon oxide layer during etching at the tips of the pores.
Structural and electronic properties of Aun−xPtx (n = 2–14; x ⩽ n) clusters: The density functional theory investigation
Authors: Yuan H. K. , Kuang A. L. , Tian C. L. , Chen H.
Published: March 2014

The structural evolutions and electronic properties of bimetallic Aun–xPtx (n = 2–14; x ⩽ n) clusters are investigated by using the density functional theory (DFT) with the generalized gradient approximation (GGA). The monatomic doping Aun–1Pt clusters are emphasized and compared with the corresponding pristine Aun clusters. The results reveal that the planar configurations are favored for both Aun–1Pt and Aun clusters with size up to n = 13, and the former often employ the substitution patterns based on the structures of the latter. The most stable clusters are Au6 and Au6Pt, which adopt regular planar triangle (D3h) and hexagon-ring (D6h) structures and can be regarded as the preferential building units in designing large clusters. For Pt-rich bimetallic clusters, their structures can be obtained from the substitution of Pt atoms by Au atoms from the Ptn structures, where Pt atoms assemble together and occupy the center yet Au atoms prefer the apex positions showing a segregation effect. With respect to pristine Au clusters, AunPt clusters exhibit somewhat weaker and less pronounced odd-even oscillations in the highest occupied and lowest unoccupied molecular-orbital gaps (HOMO-LUMO gap), electron affinity (EA), and ionization potential (IP) due to the partially released electron pairing effect. The analyses of electronic structure indicate that Pt atoms in AuPt clusters would delocalize their one 6s and one 5d electrons to contribute the electronic shell closure. The sp-d hybridizations as well as the d-d interactions between the host Au and dopant Pt atoms result in the enhanced stabilities of AuPt clusters.
Modulation of synaptic function through the α-neurexin–specific ligand neurexophilin-1
Authors: Born Gesche , Breuer Dorothee , Wang Shaopeng , Rohlmann Astrid , Coulon Philippe , Vakili Puja , Reissner Carsten , Kiefer Friedemann , Heine Martin , Pape Hans-Christian , Missler Markus
Published: March 2014

Significance

Communication between neurons via synapses is essential for information processing and cognitive function in our brains and is found impaired in many neuropsychiatric disorders. Synaptic transmission is remarkably variable in strength, and cell-adhesion molecules as neurexins and their binding partners are candidates to regulate neurotransmission. This study changes our understanding of how neurotransmission can be adapted to local demands by investigating the previously undescribed functions of neurexophilins, arguably the most elusive ligands of α-neurexins. Neurexophilins are expressed only in subpopulations of synapses, and their presence is able to change short-term plasticity and molecular composition at these terminals.
Kinetic evidence for a two-stage mechanism of protein denaturation by guanidinium chloride
Authors: Jha Santosh Kumar , Marqusee Susan
Published: March 2014

Significance

Guanidinium chloride (GdmCl) has been used to modulate the stability of proteins for more than 50 years; surprisingly, however, the molecular mechanism of its action is still poorly understood. Here, we provide direct kinetic evidence for the hypothesis that GdmCl unfolds proteins by a two-step mechanism. In the first step, it binds to the protein surface, resulting in the formation of a “dry molten globule,” an expanded form of the native protein with a dry core. Core solvation and global structural disruption occur in the second step. The observation of a dry molten globule during unfolding indicates that dispersion forces, and not only the hydrophobic effect, also play an important role in stabilizing proteins.
Toward global mapping of river discharge using satellite images and at-many-stations hydraulic geometry
Authors: Gleason Colin J. , Smith Laurence C.
Published: March 2014

Significance

Political and practical realities limit our knowledge of water resources in many parts of the world. Here, we present a radically different approach for quantitative remote sensing of river discharge (flow rate) that is enabled by advancing a classic theory of river hydraulics and adapting it for use with satellite or aerial images. Because no ground-based information is required, the approach holds promise for addressing pressing societal, ecological, and scientific problems through global mapping of river flow.
The reputational and social network benefits of prosociality in an Andean community
Authors: Lyle Henry F. , Smith Eric A.
Published: March 2014

Significance

Scientists have long debated how group cooperation can be maintained. From many standard evolutionary and economic perspectives, the best decision for an individual is to engage in free riding on the cooperation of others (i.e., share in the benefits but pay no costs). Such free riding, however, reduces the collective benefits of group cooperation and can unravel cooperation. Some propose that this “tragedy of the commons” can be solved if cooperators are compensated with reputational benefits. Our research in an Andean community found that cooperative households have better reputations for various qualities and have larger support networks, with the latter associated with healthier households. This finding supports the argument that positive reputations gained by cooperators can solve the tragedy of the commons.
Improving the lens design and performance of a contemporary electromagnetic shock wave lithotripter
Authors: Neisius Andreas , Smith Nathan B. , Sankin Georgy , Kuntz Nicholas John , Madden John Francis , Fovargue Daniel E. , Mitran Sorin , Lipkin Michael Eric , Simmons Walter Neal , Preminger Glenn M. , Zhong Pei
Published: March 2014

Significance

Electromagnetic (EM) shock wave lithotripters are widely used for noninvasive treatment of kidney stone patients. Here, we report the design of a new acoustic lens to rectify three fundamental drawbacks in contemporary EM lithotripters, based on in situ pulse superposition, leading to significantly improved stone comminution both in vitro and in vivo with minimal tissue injury. The new lens design improves the pressure distribution around the lithotripter focus with better alignment of the peak pressure and cavitation activities with the kidney stones under clinically relevant treatment conditions. The general principle of the new lens design is applicable to different lenses or reflectors and with further optimizations may enhance the performance and safety of contemporary EM lithotripters.
Aβ-induced Golgi fragmentation in Alzheimer’s disease enhances Aβ production
Authors: Joshi Gunjan , Chi Youjian , Huang Zheping , Wang Yanzhuang
Published: March 2014

Significance

In Alzheimer’s disease (AD), formation of the Aβ aggregates occurs by the cleavage of the amyloid precursor protein (APP) during its trafficking inside the nerve cells. The Golgi apparatus plays a critical role in APP trafficking; fragmentation of the normally highly ordered Golgi structure occurs in nerve cells of AD patients. Here we report that Aβ accumulation triggers Golgi fragmentation by activating cyclin-dependent kinase-5 (cdk5), which phosphorylates Golgi structural proteins such as GRASP65. Rescue of Golgi structure by inhibiting cdk5 or by expressing nonphosphorylatable GRASP65 mutants reduced Aβ secretion. Our study provides a molecular mechanism for Golgi fragmentation and its effects on APP trafficking and processing, suggesting Golgi as a potential drug target for AD treatment.
Using ancient DNA to study the origins and dispersal of ancestral Polynesian chickens across the Pacific
Authors: Thomson Vicki A. , Lebrasseur Ophélie , Austin Jeremy J. , Hunt Terry L. , Burney David A. , Denham Tim , Rawlence Nicolas J. , Wood Jamie R. , Gongora Jaime , Girdland Flink Linus , Linderholm Anna , Dobney Keith , Larson Greger , Cooper Alan
Published: March 2014

Significance

Ancient DNA sequences from chickens provide an opportunity to study their human-mediated dispersal across the Pacific due to the significant genetic diversity and range of archaeological material available. We analyze ancient and modern material and reveal that previous studies have been impacted by contamination with modern chicken DNA and, that as a result, there is no evidence for Polynesian dispersal of chickens to pre-Columbian South America. We identify genetic markers of authentic ancient Polynesian chickens and use them to model early chicken dispersals across the Pacific. We find connections between chickens in the Micronesian and Bismarck Islands, but no evidence these were involved in dispersals further east. We also find clues about the origins of Polynesian chickens in the Philippines.
Embryonic thermosensitive TRPA1 determines transgenerational diapause phenotype of the silkworm,Bombyx mori
Authors: Sato Azusa , Sokabe Takaaki , Kashio Makiko , Yasukochi Yuji , Tominaga Makoto , Shiomi Kunihiro
Published: March 2014

Significance

Diapause has evolved as a specific subtype of dormancy in most insect species and as a seasonal polyphenism that ensures survival under unfavorable environmental conditions and synchronizes populations. InBombyx mori, embryonic diapause is induced transgenerationally as a maternal effect. However, the molecular mechanisms involved in the perception of environmental temperature and in linking thermal information to neuroendocrine functions are still unknown. Here, we show that theBombyxtransient receptor potential A1 (TRPA1) could be thermally activated during embryogenesis, and an unknown signaling pathway linked to the release of diapause hormone may then be activated to affect the induction of diapause in progeny. TheBombyxTRPA1 acts as a molecular switch for the development of an alternative phenotype in an animal with seasonal polyphenism.
Chloroplast remodeling during state transitions in
Chlamydomonas reinhardtii
as revealed by noninvasive techniques in vivo
Authors: Nagy Gergely , Ünnep Renáta , Zsiros Ottó , Tokutsu Ryutaro , Takizawa Kenji , Porcar Lionel , Moyet Lucas , Petroutsos Dimitris , Garab Győző , Finazzi Giovanni , Minagawa Jun
Published: March 2014

Significance

Oxygenic photosynthesis regulates light–energy conversion by balancing the activity of the two photosystems (PSs). Such a power balance requires a sophisticated regulatory mechanism called state transitions, which involve reversible phosphorylation of the light-harvesting complex proteins (LHCIIs) to redistribute absorbed excitation energy between the two photosystems. Using noninvasive techniques (small-angle neutron scattering, circular dichroism, and absorption transient spectroscopy) in the green alga
Chlamydomonas reinhardtii
, we have revealed that state transitions modify the chloroplast structure, affecting the stacking and periodicity of the photosynthetic membranes and altering protein–protein interactions within these membranes. These structural changes accompany the conversion of LHCII into an energy-dissipating mode with only minor displacements of phosphorylated LHCIIs from PSII to PSI, thereby allowing us to reevaluate the physiological significance of state transitions.
Shifts in flowering phenology reshape a subalpine plant community
Authors: CaraDonna Paul J. , Iler Amy M. , Inouye David W.
Published: March 2014

Significance

Seasonal timing of biological events, phenology, is one of the strongest bioindicators of climate change. Our general understanding of phenological responses to climate change is based almost solely on the first day on which an event is observed, limiting our understanding of how ecological communities may be responding as a whole. Using a unique long-term record of flowering phenology from Colorado, we find that the number of species changing their flowering times likely has been underestimated and the magnitude of phenological change overestimated. In addition to earlier first flowering, we document a diverse assortment of other changes, such as delayed last flowering, as temperatures warm. This variety of species-level phenological shifts has ultimately reshaped various temporal components of the plant community.
RSPO–LGR4 functions via IQGAP1 to potentiate Wnt signaling
Authors: Carmon Kendra S. , Gong Xing , Yi Jing , Thomas Anthony , Liu Qingyun
Published: March 2014

Significance

R-spondins (RSPOs) and LGR4 emerged as a major ligand–receptor system in the regulation of Wnt signaling as manifested in their pleotropic roles in development and survival of adult stem cells. The mechanism of how RSPO–LGR4 interacts with the Wnt signaling system remains poorly understood. In this work, we describe the identification of IQGAP1 as the first intracellular signaling partner of RSPO–LGR4 and the delineation of IQGAP1’s roles and mechanism in mediating RSPO–LGR4-induced potentiation of Wnt signaling. We also elucidate the relationship between the RSPO–LGR4–IQGAP1 pathway and the function of RSPO–LGR4 in inhibiting RNF43/ZNRF3. The findings uncovered a unique mechanism of RSPO–LGR4 signaling and provide a mechanistic basis for the pleiotropic functions of RSPO–LGR4 signaling in normal and pathological processes.
Methylcitrate cycle defines the bactericidal essentiality of isocitrate lyase for survival of
Mycobacterium tuberculosis
on fatty acids
Authors: Eoh Hyungjin , Rhee Kyu Y.
Published: March 2014

Significance

Essentiality is a phenotypic trait of genes frequently used to identify new potential drug targets. However, genes function within the context of complex and extensively interconnected physiologic networks, making it difficult to discern the specific mechanisms responsible for their essentiality. Here, we apply a combination of chemogenetic and metabolomic approaches to resolve the specific biochemical mechanism associated with the bactericidal essentiality of the metabolic enzyme, isocitrate lyase (ICL), for survival of
Mycobacterium tuberculosis
(Mtb), a chronic intracellular pathogen, on fatty acids, a major carbon source thought to be encountered in vivo. These studies not only provide a systems level insight into the essentiality of Mtb’s ICL but also reveal a previously unrecognized link between propionate metabolism and membrane bioenergetics.
Role of BRCA1 in brain development
Authors: Pao Gerald M. , Zhu Quan , Perez-Garcia Carlos G. , Chou Shen-Ju , Suh Hoonkyo , Gage Fred H. , O’Leary Dennis D. M. , Verma Inder M.
Published: March 2014

Significance

The developing brain is highly sensitive to ionizing radiation and DNA damage. Here we report that tumor suppressor breast cancer susceptibility gene 1 (
BRCA1
) plays a novel role in regulating the embryonic brain development and postnatal brain size. We found that loss of
BRCA1
induces p53-dependent proapoptotic pathways in the CNS.
BRCA1
possibly functions as a centrosomal factor in establishing the cellular polarity of the neural progenitors through the DNA damage sensor kinase ATM. Our data provide new insight in understanding the control of DNA damage sensitivity and brain size during development and evolution.
Hybridization gap and Fano resonance in SmB6
Authors: Rößler Sahana , Jang Tae-Hwan , Kim Dae-Jeong , Tjeng L. H. , Fisk Zachary , Steglich Frank , Wirth Steffen
Published: March 2014

Significance

Quantum entanglement may give rise to emerging phenomena and new states of matter. In the intermediate-valence material SmB6, this is realized via hybridization between localized 4fand conduction band states that, at sufficiently low temperatures, results in the screening of the 4flocal moments by the conduction electrons and produces a so-called Kondo resonance in the density of states. The latter is examined by scanning tunneling spectroscopy down to temperatures well below the Kondo temperature. This atomically resolved spectroscopy allows one to distinguish between reconstructed and pristine surfaces and different surface terminations, all of which influence the spectroscopic results. These insights are vital for other, less local spectroscopic tools in the context of possible topologically protected surface states.
Nitrogen isotope fractionation by alternative nitrogenases and past ocean anoxia
Authors: Zhang Xinning , Sigman Daniel M. , Morel François M. M. , Kraepiel Anne M. L.
Published: March 2014

Significance

Biological nitrogen fixation is the main route by which nitrogen enters the biosphere. This reaction is catalyzed by nitrogenase, a metalloenzyme that exists in forms containing molybdenum, vanadium, or iron only. The contribution of the “alternative” vanadium and iron-only nitrogenases to nitrogen fixation in the present and the past is unknown. Here we show that the nitrogen isotopic composition (15N to14N ratio) of biomass generated from nitrogen fixation by alternative nitrogenases is significantly and characteristically lower than biomass produced by molybdenum nitrogenases. In light of these results, nitrogen isotope measurements in ancient sediments imply an important role for iron-only nitrogenases in nitrogen fixation within certain anoxic, molybdenum-limited ancient environments.
Cartography of neurexin alternative splicing mapped by single-molecule long-read mRNA sequencing
Authors: Treutlein Barbara , Gokce Ozgun , Quake Stephen R. , Südhof Thomas C.
Published: March 2014

Significance

Neurexins are presynaptic cell-adhesion molecules that are essential for synapse formation and synaptic transmission. Extensive alternative splicing of neurexin transcripts may generate thousands of isoforms, but it is unclear how many distinct neurexins are physiologically produced. We used unbiased long-read sequencing of full-length neurexin mRNAs to systematically assess the alternative splicing of neurexins in prefrontal cortex. We identified a novel, abundantly used alternatively spliced exon of neurexins, and found that the different events of alternative splicing of neurexins appear to be independent of each other. Our data suggest that thousands of neurexin isoforms are physiologically generated, consistent with the notion that neurexins represent transsynaptic protein-interaction scaffolds that mediate diverse functions and are regulated by alternative splicing at multiple independent sites.