bluuebunny/crossref_metadata_2025 huggingface dataset:
Design of two and three input molecular logic gates using non-Watson–Crick base pairing-based molecular beacons
Authors: Lin Jia-Hui , Tseng Wei-Lung
Published: January 2014

A single, resettable, and sensitive molecular beacon has been developed to operate two-input, three-input, and set–reset logic gates.
Development and validation of a microbiological assay by turbidimetry to determine the potency of cefazolin sodium in the lyophilized powder form
Authors: Pedroso Tahisa Marcela , Nunes Salgado Hérida Regina
Published: January 2014

In this paper a new microbiological method for quantifying and evaluating the potency of cefazolin sodium is presented in order to produce safe medicines for the population.
Simultaneous determination of eighteen perfluorinated compounds in dissolved and particulate phases of wastewater, and in sewage sludge by liquid chromatography-tandem mass spectrometry
Authors: Arvaniti Olga S. , Asimakopoulos Alexandros G. , Dasenaki Marilena E. , Ventouri Elpida I. , Stasinakis Athanasios S. , Thomaidis Nikolaos S.
Published: January 2014

Integrated simultaneous determination of 18 perfluorinated compounds in wastewater and sewage sludge.
X-ray chemical imaging and the electronic structure of a single nanoplatelet Ni/graphene composite
Authors: Zhou Chunyu , Wang Jian , Szpunar Jerzy A.
Published: January 2014

Local chemistry and electronic structure of Ni/graphene composite reveal that Ni is grown onto graphene substrates mainlyviacovalent bonding of Ni–C and Ni–O–C.
Catalytic asymmetric conjugate addition of terminal alkynes to β-trifluoromethyl α,β-enones
Authors: Sanz-Marco Amparo , García-Ortiz Andrea , Blay Gonzalo , Pedro José R.
Published: January 2014

The first enantioselective conjugate alkynylation of β-trifluoromethyl α,β-enones using terminal alkynes and a taniaphos–Cu(i) complex as catalyst is described.
Experimental evaluation of the electron donor ability of a gold phosphine fragment in a gold carbene complex
Authors: Brooner Rachel E. M. , Widenhoefer Ross A.
Published: January 2014

Bond length deformations within the cyclopropyl ring of a gold cyclopropyl(methoxy)carbene complex provide an experimental measure of the electron donor ability of the gold phosphine fragment.
Quantitative kinetic investigation of triazole–gold(i) complex catalyzed [3,3]-rearrangement of propargyl ester
Authors: Xi Yumeng , Wang Qiaoyi , Su Yijin , Li Minyong , Shi Xiaodong
Published: January 2014

The kinetic study of triazole–Au catalyzed propargylic ester rearrangement was performed, which offered new mechanistic insight into gold catalysis.
Gold(i)-catalysed [1,3] O→C rearrangement of allenyl ethers
Authors: Kona Chandrababu Naidu , Ramana Chepuri V.
Published: January 2014

Gold standard: a simple and rapid access to the α-substituted acryl aldehydes has been provided by developing a gold-catalysed [1,3] rearrangement of the allenyl ethers importantly with a record turnover frequency = 4600 h−1 (at 0.05 mol% of the catalyst concentration) in homogeneous gold(i) catalysis.
The diversity of Zn(ii) coordination networks composed of multi-interactive ligand TPHAP−via weak intermolecular interaction
Authors: Kojima Tatsuhiro , Yamada Tomofumi , Yakiyama Yumi , Ishikawa Eri , Morita Yasushi , Ebihara Masahiro , Kawano Masaki
Published: January 2014

Seven types of different Zn(TPHAP) coordination networks were prepared thanks to the excellent multi-interactivity of TPHAP via weak intermolecular interactions.
Template-free preparation and properties of mesoporous g-C3N4/TiO2nanocomposite photocatalyst
Authors: Shen Jianchao , Yang Hui , Shen Qianhong , Feng Yu , Cai Qifeng
Published: January 2014

A facile template-free method was proposed to fabricate a novel network structured mesoporous g-C3N4/TiO2nano-heterojunction compositeviaprotonation of base functionalities during thein situgrowth of TiO2nanoparticles on the surface of g-C3N4under hydrothermal conditions.
Lipid charge regulation of non-specific biological ion channels
Authors: Aguilella Vicente M. , Verdiá-Báguena Carmina , Alcaraz Antonio
Published: January 2014

Lipid charge regulation effects in different protein–lipid conformations highlight the role of electrostatic interactions in conductance and selectivity of non-specific biological ion channels.
Structural variation in Zn(ii) coordination polymers built with a semi-rigid tetracarboxylate and different pyridine linkers: synthesis and selective CO2 adsorption studies
Authors: Sen Susan , Neogi Subhadip , Aijaz Arshad , Xu Qiang , Bharadwaj Parimal K.
Published: January 2014

The C2v or Cs symmetry in the flexible 3,3′,5,5′-tetracarboxydiphenylmethane ligand directs the stability and porosity of the resulting frameworks in the presence of Zn(ii) ions, and pyridine linkers of comparable lengths.
Fundamental chemistry of iodine. The reaction of di-iodine towards thiourea and its methyl-derivative: formation of aminothiazoles and aminothiadiazoles through dicationic disulfides
Authors: Biesiada M. , Kourkoumelis N. , Kubicki M. , Owczarzak A. M. , Balas V. , Hadjikakou S. K.
Published: January 2014

The reactivity of di-iodine towards thiourea (TU) and its derivative methylthiourea (MeTU) is studied. A diversity of products was obtained from these reactions.
Optimization of the neutralization of Red Mud by pyrolysis bio-oil using a design of experiments approach
Authors: Jollet Véronique , Gissane Christopher , Schlaf Marcel
Published: January 2014

Co-processing alkaline Red Mud (bauxite residue) with acidic pyrolysis bio-oil yields a gray pH-neutral solid containing ∼30% (w/w) biomass derived carbon and magnetic iron suboxides.
Effect of dietary antioxidants on the cytostatic effect of acrylamide during copper-deficiency in Saccharomyces cerevisiae
Authors: Kommuguri Upendra Nadh , Satyaprasad Pallem Poorna Venkata , Bodiga Sreedhar , Bodiga Vijaya Lakshmi
Published: January 2014

Yeast grown on a copper deficient medium was used to study acrylamide toxicity, obviating the need for genetic manipulation and accompanying compensatory effects.
Response of single leukemic cells to peptidase inhibitor therapy across time and dose using a microfluidic device
Authors: Kovarik Michelle L. , Dickinson Alexandra J. , Roy Pourab , Poonnen Ranjit A. , Fine Jason P. , Allbritton Nancy L.
Published: January 2014

Microfluidic single-cell assays of peptide degradation were performed at varying inhibitor doses, and the resulting data were analyzed by regression modeling to reveal biological effects.
Microfluidic fabrication of cell-derived nanovesicles as endogenous RNA carriers
Authors: Jo Wonju , Jeong Dayeong , Kim Junho , Cho Siwoo , Jang Su Chul , Han Chungmin , Kang Ji Yoon , Gho Yong Song , Park Jaesung
Published: January 2014

Artificial exosomes of ~100 nm diameter, enclosed with lipid bilayers, are fabricated from living cells and transfer biological signal components such as encapsulated RNAs and proteins, plasma membrane proteins, or both.
A microfluidic platform for chemoresistive testing of multicellular pleural cancer spheroids
Authors: Ruppen Janine , Cortes-Dericks Lourdes , Marconi Emanuele , Karoubi Golnaz , Schmid Ralph A. , Peng Renwang , Marti Thomas M. , Guenat Olivier T.
Published: January 2014

This study reports on a microfluidic platform on which single multicellular spheroids from malignant pleural mesothelioma (MPM), an aggressive tumor with poor prognosis, can be loaded, trapped and tested for chemotherapeutic drug response.
Nanomechanical identification of liquid reagents in a microfluidic channel
Authors: Faheem Khan M. , Kim Seonghwan , Lee Dongkyu , Schmid Silvan , Boisen Anja , Thundat Thomas
Published: January 2014

A bimetallic microchannel cantilever is employed to characterize picoliter volumes of liquid reagents.
Plant chip for high-throughput phenotyping of Arabidopsis
Authors: Jiang Huawei , Xu Zhen , Aluru Maneesha R , Dong Liang
Published: January 2014

A vertical microfluidic plant chip technology is developed to establish a powerful experimental framework for high-throughput and precise plant phenotyping.
Recoverable Cu/SiO2 composite-catalysed click synthesis of 1,2,3-triazoles in water media
Authors: Radatz Cátia Schwartz , Soares Liliana do Amaral , Vieira Estéfano Roberto , Alves Diego , Russowsky Dennis , Schneider Paulo Henrique
Published: January 2014

An eco-friendly multicomponent reaction for the synthesis of 1,2,3-triazoles using a recoverable and recyclable Cu/SiO2 composite as the catalyst is reported.
Rational design of a rapid fluorescent approach for detection of inorganic fluoride in MeCN–H2O: a new fluorescence switch based on N-aryl-1,8-naphthalimide
Authors: Bamesberger Angela , Schwartz Christopher , Song Qiao , Han Weiwei , Wang Zhi , Cao Haishi
Published: January 2014

A desilylation based sensor showed high selectivity and sensitivity to fluoride in MeCN–H2O media.
A new hierarchically porous Pd@HSQ monolithic catalyst for Mizoroki–Heck cross-coupling reactions
Authors: Moitra Nirmalya , Matsushima Ayumi , Kamei Toshiyuki , Kanamori Kazuyoshi , Ikuhara Yumi H. , Gao Xiang , Takeda Kazuyuki , Zhu Yang , Nakanishi Kazuki , Shimada Toyoshi
Published: January 2014

Palladium nanoparticles are embedded in hierarchically porous hydrogen silsesquioxane monoliths by on-site reduction to prepare a reusable catalyst for Mizoroki–Heck reactions.
Enantioselective organocatalytic oxa-Michael addition of oximes to β-CF3-β-disubstituted nitroalkenes: efficient synthesis of β-amino-α-trifluoromethyl alcohols
Authors: Liu Feng-Lei , Chen Jia-Rong , Feng Bin , Hu Xiao-Qiang , Ye Li-Hua , Lu Liang-Qiu , Xiao Wen-Jing
Published: January 2014

An enantioselective intermolecular oxa-Michael addition of oximes to β-CF3-β-disubstituted nitroalkenes has been developed.
Electron transport in DNA initiated by diaminonaphthalene donors alternatively bound by non-covalent and covalent association
Authors: Campbell Neil P. , Rokita Steven E.
Published: January 2014

Non-covalent association can identify active donors for study of charge transfer in DNA but may not establish detailed correlations between donor structure and transfer efficiency.
Facile preparation of supramolecular (ABAC)n multiblock copolymers from Hamilton wedge and barbiturate-functionalized RAFT agents
Authors: Chen Senbin , Deng Yuanming , Chang Xijun , Barqawi Haitham , Schulz Matthias , Binder Wolfgang H.
Published: January 2014

The facile preparation of novel supramolecular (ABAC)n multiblock copolymers from Hamilton wedge and barbiturate functionalized H-bonding RAFT agents is reported.
Unimolecular micelles composed of inner coil-like blocks and outer rod-like blocks crafted by combination of living polymerization with click chemistry
Authors: Pang Xinchang , Feng Chaowei , Xu Hui , Han Wei , Xin Xukai , Xia Haiping , Qiu Feng , Lin Zhiqun
Published: January 2014

Star-shaped PS-b-P3HT was synthesized via a combination of ATRP, GRIM polymerization, and click reaction. They possessed different properties as compared to their linear analogues
Combi-lipase for heterogeneous substrates: a new approach for hydrolysis of soybean oil using mixtures of biocatalysts
Authors: Alves Joana S. , Vieira Nathália S. , Cunha Alisson S. , Silva Alexandre M. , Záchia Ayub Marco A. , Fernandez-Lafuente Roberto , Rodrigues Rafael C.
Published: January 2014

The concept of thecombi-lipasebiocatalyst has been proposed. It is based on the combination of different lipases as biocatalysts in reactions using heterogeneous substrates.
Total synthesis and characterization of thielocin B1 as a protein–protein interaction inhibitor of PAC3 homodimer
Authors: Doi Takayuki , Yoshida Masahito , Ohsawa Kosuke , Shin-ya Kazuo , Takagi Motoki , Uekusa Yoshinori , Yamaguchi Takumi , Kato Koichi , Hirokawa Takatsugu , Natsume Tohru
Published: January 2014

We have characterized the inhibition of the protein–protein interaction of the homodimer of proteasome assembling chaperone (PAC) 3 with thielocin B1.
Fabrication of 3D ZnO hollow shell structures by prism holographic lithography and atomic layer deposition
Authors: Park Sung-Gyu , Jeon Tae Yoon , Jeon Hwan Chul , Yang Seung-Man , Kwon Jung-Dae , Mun Chae-Won , Cho Byungjin , Kim Chang Su , Kim Dong-Ho
Published: January 2014

This paper presents the fabrication of 3D ZnO hollow shell structures using prism holographic lithography and atomic layer deposition.
Neuregulin-1β induces embryonic stem cell cardiomyogenesis via ErbB3/ErbB2 receptors
Authors: Hao Jijun , Galindo Cristi L. , Tran Truc-Linh , Sawyer Douglas B.
Published: January 2014

NRG-1β (neuregulin-1β) serves multiple functions during embryonic heart development by signalling through ErbB family receptor tyrosine kinases (ErbB2, ErbB3 and ErbB4). Previous studies reported that NRG-1β induces cardiomyogenesis of mESCs (mouse embryonic stem cells) at the later stages of differen-tiation through ErbB4 receptor activation. In the present study we systematically examined NRG-1β induction of cardiac myocytes in mESCs and identified a novel time window, the first 48 h, for NRG-1β-based cardiomyogenesis. At this time point ErbB3, but not ErbB4, is expressed. In contrast with the later differentiation of mESCs in which NRG-1β induces cardiomyogenesis via the ErbB4 receptor, we found that knocking down ErbB3 or ErbB2 with siRNA during the early differentiation inhibited NRG-1β-induced cardiomyogenesis in mESCs. Microarray analysis of RNA expression at this early time point indicated that NRG-1β treatment in mESCs resulted in gene expression changes important to differentiation including up-regulation of components of PI3K (phosphoinositide 3-kinase), a known mediator of the NRG-1β/ErbB signalling pathway, as well as activation of CREB (cAMP-response-element-binding protein). Further study demonstrated that the NRG-1β-induced phosphorylation of CREB was required for cardiomyogenesis of mESCs. In summary, we report a previously unrecognized role for NRG-1β/ErbB3/CREB signalling at the pre-mesoderm stage for stem cell cardiac differentiation.
Tumour-associated mutations of PA-TM-RING ubiquitin ligases RNF167/RNF13 identify the PA domain as a determinant for endosomal localization
Authors: van Dijk Jesper R. , Yamazaki Yasuo , Palmer Ruth H.
Published: January 2014

Diverse cellular processes depend on endocytosis, intracellular vesicle trafficking, sorting and exocytosis, and processes that are regulated post-transcriptionally by modifications such as phosphorylation and ubiquitylation. The PA (protease-associated) domain E3 ligases, such as GodzillaCG10277 in Drosophila melanogaster and RNF167 (RING finger protein 167) in humans, have been implicated in the regulation of cellular endosome trafficking. In the present study, we have characterized point mutations in the RING (really interesting new gene) domain of human RNF13 and RNF167, which have been identified in human tumour samples, that abrogate ubiquitin ligase activity as well as function. In the present study, we have also identified a functional role for the PA domain, which is required for endosomal localization of these proteins. Although the PA domain point mutations of RNF13 and RNF167 identified in human tumours are ligase active, the resultant mutant proteins are mislocalized within the cell. Thus the PA domain E3 ligases examined in the present study appear to require both E3 ligase activity as well as an intact PA domain to efficiently target and ubiquitylate their cellular substrates.
Dielectric strength of voidless BaTiO3 films with nano-scale grains fabricated by aerosol deposition
Authors: Kim Hong-Ki , Lee Seung-Hwan , In Kim Soo , Woo Lee Chang , Rag Yoon Jung , Lee Sung-Gap , Lee Young-Hie
Published: January 2014

In order to investigate the dielectric strength properties of the BaTiO3 films with nano-scale grains with uniform grain size and no voids, BaTiO3 films were fabricated with a thickness of 1 μm by an AD process, and the fabricated films were sintered at 800, 900, and 1000 °C in air and reducing atmosphere. The films have superior dielectric strength properties due to their uniform grain size and high density without any voids. In addition, based on investigation of the leakage current (intrinsic) properties, it was confirmed that the sintering conditions of the reducing atmosphere largely increase leakage currents due to generated electrons and doubly ionized oxygen vacancies following the Poole-Frenkel emission mechanism, and increased leakage currents flow at grain boundary regions. Therefore, we conclude that the extrinsic breakdown factors should be eliminated for superior dielectric strength properties, and it is important to enhance grain boundaries by doping acceptors and rare-earth elements.
Ferromagnetic resonance of sputtered yttrium iron garnet nanometer films
Authors: Liu Tao , Chang Houchen , Vlaminck Vincent , Sun Yiyan , Kabatek Michael , Hoffmann Axel , Deng Longjiang , Wu Mingzhong
Published: January 2014

Growth of nm-thick yttrium iron garnet (YIG) films by sputtering and ferromagnetic resonance (FMR) properties in the films were studied. The FMR linewidth of the YIG film decreased as the film thickness was increased from several nanometers to about 100 nm. For films with very smooth surfaces, the linewidth increased linearly with frequency. In contrast, for films with big grains on the surface, the linewidth-frequency response was strongly nonlinear. Films in the 7–26 nm thickness range showed a surface roughness between 0.1 nm and 0.4 nm, a 9.48-GHz FMR linewidth in the 6–10 Oe range, and a damping constant of about 0.001.
A numerical approach to incorporate intrinsic material defects in micromagnetic simulations
Authors: Leliaert J. , Van de Wiele B. , Vansteenkiste A. , Laurson L. , Durin G. , Dupré L. , Van Waeyenberge B.
Published: January 2014

Spintronics devices like racetrack memory rely on the controlled movement of domain walls in magnetic nanowires. The effects of distributed disorder on this movement have not yet been studied extensively. Defects give rise to a pinning potential that can be characterized in terms of a depth and an interaction range. We investigate how the effects of defects can be realistically introduced in micromagnetic simulations by comparing the properties of the pinning potential to experimental results in the literature. We show that the full 3-dimensional simulations can be replaced by equivalent 2-dimensional ones and propose two approaches to include defects.
Response to “Comment on ‘Motion of a helical vortex filament in superfluid 4He under the extrinsic form of the local induction approximation”’ [Phys. Fluids 26, 019101 (2014)]
Authors: Van Gorder Robert A.
Published: January 2014

I agree with the authors regarding their comments on the Donnelly-Glaberson instability for such helical filaments as those obtained in my paper. I also find merit in their derivation of the quantum LIA (local induction approximation) in the manner of the LIA of Boffetta et al. However, I disagree with the primary criticisms of Hietala and Hänninen. In particular, though they suggest LIA and local nonlinear equation modes are not comparable since the former class of models contains superfluid friction parameters, note that since these parameters are small one may take them to zero and consider a qualitative comparison of the models (which is what was done in my paper). Second, while Hietala and Hänninen criticize certain assumptions made in my paper (and the paper of Shivamoggi where the model comes from) since the results break-down when Ak → ∞, note that in my paper I state that any deviations from the central axis along which the filament is aligned must be sufficiently bounded in variation. Therefore, it was already acknowledged that Ak(=|Φx|) should be sufficiently bounded, precluding the Ak → ∞ case. I also show that, despite what Hietala and Hänninen claim, the dispersion relation obtained in my paper is consistent with LIA, where applicable. Finally, while Hietala and Hänninen claim that the dispersion parameter should be complex valued, I show that their dispersion relation is wrong, since it was derived incorrectly (they assume the complex modulus of the potential function is constant, yet then use this to obtain a potential function with non-constant modulus).
Angular dependence of anisotropic magnetoresistance in magnetic systems
Authors: Zhang Steven S.-L. , Zhang Shufeng
Published: January 2014

Anisotropic magnetoresistance (AMR), whose physical origin is attributed to the combination of spin dependent scattering and spin orbital coupling (SOC), usually displays simple angular dependence for polycrystalline ferromagnetic metals. By including generic spin dependent scattering and spin Hall (SH) terms in the Ohm's law, we explicitly show that various magneto-transport phenomena such as anomalous Hall (AH), SH, planar Hall (PH) and AMR could be quantitatively related for bulk polycrystalline ferromagnetic metals. We also discuss how AMR angular dependence is affected by the presence of interfacial SOC in magnetic layered structure.
Multi-layer Potfit: An accurate potential representation for efficient high-dimensional quantum dynamics
Authors: Otto Frank
Published: January 2014

The multi-layer multi-configuration time-dependent Hartree method (ML-MCTDH) is a highly efficient scheme for studying the dynamics of high-dimensional quantum systems. Its use is greatly facilitated if the Hamiltonian of the system possesses a particular structure through which the multi-dimensional matrix elements can be computed efficiently. In the field of quantum molecular dynamics, the effective interaction between the atoms is often described by potential energy surfaces (PES), and it is necessary to fit such PES into the desired structure. For high-dimensional systems, the current approaches for this fitting process either lead to fits that are too large to be practical, or their accuracy is difficult to predict and control. This article introduces multi-layer Potfit (MLPF), a novel fitting scheme that results in a PES representation in the hierarchical tensor (HT) format. The scheme is based on the hierarchical singular value decomposition, which can yield a near-optimal fit and give strict bounds for the obtained accuracy. Here, a recursive scheme for using the HT-format PES within ML-MCTDH is derived, and theoretical estimates as well as a computational example show that the use of MLPF can reduce the numerical effort for ML-MCTDH by orders of magnitude, compared to the traditionally used POTFIT representation of the PES. Moreover, it is shown that MLPF is especially beneficial for high-accuracy PES representations, and it turns out that MLPF leads to computational savings already for comparatively small systems with just four modes.
Design optimization of high pressure and high temperature piezoresistive pressure sensor for high sensitivity
Authors: Niu Zhe , Zhao Yulong , Tian Bian
Published: January 2014

This paper describes a design method for optimizing sensitivity of piezoresistive pressure sensor in high-pressure and high-temperature environment. In order to prove the method, a piezoresistive pressure sensor (HPTSS) is designed. With the purpose of increasing sensitivity and to improve the measurement range, the piezoresistive sensor adopts rectangular membrane and thick film structure. The configuration of piezoresistors is arranged according to the characteristic of the rectangular membrane. The structure and configuration of the sensor chip are analyzed theoretically and simulated by the finite element method. This design enables the sensor chip to operate in high pressure condition (such as 150 MPa) with a high sensitivity and accuracy. The silicon on insulator wafer is selected to guarantee the thermo stability of the sensor chip. In order to optimize the fabrication and improve the yield of production, an electric conduction step is devised. Series of experiments demonstrates a favorable linearity of 0.13% and a high accuracy of 0.48%. And the sensitivity of HTPSS is about six times as high as a conventional square-membrane sensor chip in the experiment. Compared with the square-membrane pressure sensor and current production, the strength of HPTTS lies in sensitivity and measurement. The performance of the HPTSS indicates that it could be an ideal candidate for high-pressure and high-temperature sensing in real application.
Compact fluxgate magnetic full-tensor gradiometer with spherical feedback coil
Authors: Sui Yangyi , Li Guang , Wang Shilong , Lin Jun
Published: January 2014

The magnetic tensor gradiometer, which is used for measuring the spatial derivatives of three orthogonal magnetic field components, is an important magnetic field characterization tool. Here, the construction of a magnetic full-tensor gradiometer is described, which utilizes four fluxgates arranged on a planar cross structure, and a single, triaxial, spherical feedback coil assembly. In this arrangement, one of the fluxgates is used as a reference, controlling the currents through the feedback coils. Since the fluxgates are working in the near-zero magnetic field environment, the magnetic tensor gradiometer is stable and of an improved accuracy. This design avoids the crosstalk normally caused by individual feedback coils for each fluxgate, and reduces the orthogonality and orientation errors. Moreover, the calibration parameters can be directly inferred using the spherical feedback coil. The measured gradient tensor magnitude can reach 0.52 nT/m/Hz1/2 @ 1 Hz in unshielded laboratory conditions, while exhibiting good noise immunity. The functionality of the system is verified by locating a small, single, permanent, and dipole magnet in space. The gradiometer is compact, while employing global feedback, and therefore it is especially suitable for deployment on space-constrained moving platforms.
Electronic and vibronic properties of a discotic liquid-crystal and its charge transfer complex
Authors: Haverkate Lucas A. , Zbiri Mohamed , Johnson Mark R. , Carter Elizabeth , Kotlewski Arek , Picken S. , Mulder Fokko M. , Kearley Gordon J.
Published: January 2014

Discotic liquid crystalline (DLC) charge transfer (CT) complexes combine visible light absorption and rapid charge transfer characteristics, being favorable properties for photovoltaic (PV) applications. We present a detailed study of the electronic and vibrational properties of the prototypic 1:1 mixture of discotic 2,3,6,7,10,11-hexakishexyloxytriphenylene (HAT6) and 2,4,7-trinitro-9-fluorenone (TNF). It is shown that intermolecular charge transfer occurs in the ground state of the complex: a charge delocalization of about 10−2 electron from the HAT6 core to TNF is deduced from both Raman and our previous NMR measurements [L. A. Haverkate, M. Zbiri, M. R. Johnson, B. Deme, H. J. M. de Groot, F. Lefeber, A. Kotlewski, S. J. Picken, F. M. Mulder, and G. J. Kearley, J. Phys. Chem. B 116, 13098 (2012)], implying the presence of permanent dipoles at the donor-acceptor interface. A combined analysis of density functional theory calculations, resonant Raman and UV-VIS absorption measurements indicate that fast relaxation occurs in the UV region due to intramolecular vibronic coupling of HAT6 quinoidal modes with lower lying electronic states. Relatively slower relaxation in the visible region the excited CT-band of the complex is also indicated, which likely involves motions of the TNF nitro groups. The fast quinoidal relaxation process in the hot UV band of HAT6 relates to pseudo-Jahn-Teller interactions in a single benzene unit, suggesting that the underlying vibronic coupling mechanism can be generic for polyaromatic hydrocarbons. Both the presence of ground state CT dipoles and relatively slow relaxation processes in the excited CT band can be relevant concerning the design of DLC based organic PV systems.
Structural characterization of ion-vapor deposited hydrogenated amorphous carbon coatings by solid state 13C nuclear magnetic resonance
Authors: Xu Jiao , Watanabe Sadayuki , Hayashi Hideo , Kawaguchi Masahiro , Kato Takahisa
Published: January 2014

In the present study, unique structural heterogeneity was observed in ion-vapor deposited a-C:H coatings by performing 13C MAS and 1H-13C CPMAS experiments on solid state nuclear magnetic resonance devices. Two distinct types of sp2 C clusters were discovered: one of them denoted as sp2 C′ in content of 3–12 at. % was non-protonated specifically localized in hydrogen-absent regions, while the other dominant one denoted as sp2 C″ was hydrogenated or at least proximate to proton spins. On basis of the notably analogous variation of sp2 C′ content and Raman parameters as function of substrate bias voltage in the whole range of 0.5 kV–3.5 kV, a model of nano-clustering configuration was proposed that the sp2 C′ clusters were embedded between sp2 C″ clusters and amorphous sp3 C matrix as trapped interfaces or boundaries where the sp2 carbon bonds were highly distorted. Continuous increase of bias voltage would promote the nano-clustering and re-ordering of dominant sp2 C″ clusters, thus results in a marked decrease of interspace and a change of the content of sp2 C′ clusters. Further investigation on the 13C magnetization recovery showed typical stretched-exponential approximation due to the prominent presence of paramagnetic centers, and the stretched power α varied within 0.6–0.9 from distinct types of sp2 C clusters. Differently, the magnetization recovery of 1H showed better bi-exponential approximation with long and short T1(H) fluctuated within 40–60 ms and 0.1–0.3 ms approximately in content of 80% ± 5% and 20% ± 5%, respectively, varying with various bias voltages. Meanwhile, the interrupted 13C saturation recovery with an interval of short T1(H) showed that most of quick-relaxing protons were localized in sp2 C″ clusters. Such a short T1(H) was only possibly resulted from a relaxation mechanism associated with electron-nuclear dipolar interaction or spinning diffusion, and its partial distribution in sp2 C″ clusters may imply more complex configurations of unpaired electrons in studied a-C:H coatings.
The importance of anharmonicity in thermal transport across solid-solid interfaces
Authors: Wu Xufei , Luo Tengfei
Published: January 2014

Understanding interfacial thermal transport is of great importance for applications like energy devices and thermal management of electronics. Despite the significant efforts in the past few decades, thermal transport across solid-solid interfaces is still not fully understood and cannot be accurately predicted. Anharmonicity is often ignored in many prediction models, such as the mismatch models, the wave-packet method, and the Atomic Green's function. In this paper, we use molecular dynamics to systematically study the role of anharmonicity in thermal transport across solid-solid interfaces. The interatomic interactions are modeled using force constants up to the third order. This model allows controlling the anharmonicity independently by tuning the cubic force constants. The interfacial thermal conductance as a function of anharmonicity inside the materials and that at the interface is studied. We found that the anharmonicity inside the materials plays an important role in the interfacial thermal transport by facilitating the energy communication between different phonon modes. The anharmonicity at the interface has much less impact on the interfacial thermal transport. These results are important to the modification of traditional models to improve their prediction power.
Ferroelectric photovoltaic properties of Ce and Mn codoped BiFeO3 thin film
Authors: Gupta Surbhi , Tomar Monika , Gupta Vinay
Published: January 2014

Photovoltaic properties of multiferroic (Ce, Mn) codoped BiFeO3 (BCFMO) thin films grown on low cost ITO coated corning glass substrate have been investigated. The transient response of photovoltaic current of the BCFMO thin film in metal-multiferroic-metal (MMM) capacitor configuration is found to be strongly dependent on both the intensity of incident laser light (λ = 405 nm) varying from 15 mW/cm2 to 160 mW/cm2 and thickness of the BCFMO film (110 to 305 nm). Current density-voltage (J-V) measurement shows an exponential increase in photoinduced open circuit voltage and linear increase in short circuit photocurrent with increase in intensity of illuminating light. Almost 240 fold enhancement in photo-induced current is observed in BCFMO thin film of 110 nm thickness. Present work suggests that multiferroic BCFMO thin film deposited on ITO coated corning glass substrate using chemical solution deposition technique exhibits strong photovoltaic response that can be exploited efficiently for the light harvesting and photosensitive device application.
Electric field induced modification of magnetic properties in Co2Si2 multilayers
Authors: Zhang Sha , Zou Xing , Zhu Qiuxiang , Pang Hua
Published: January 2014

Effects of an external electric field on the magnetization and magnetocrystalline anisotropy (MA) in Co2Si2 multilayers are investigated by first-principles calculations. The results demonstrate that, due to the hybridization between the Si-2p orbitals and the Co-3d orbitals, the magnetic moment of the Co2Si2 supercell changes non-linearly with external electric field and the behavior of band structures near the Fermi energy could be explained within near-rigid-band model. Moreover, spin-polarized charge redistribution leads to spin reorientation and the MA is not proportional to the orbital moment anisotropy under the external electric field.
Multi-parameter magnetoelectric response modeling of magnetostrictive/piezoelectric laminate composites considering shear strain
Authors: Dai Xianzhi , Zhang Zhang , Wang Yong , Li Jianzhong , Chen Lei
Published: January 2014

A low-frequency magnetoelectric (ME) response model of magnetostrictive/piezoelectric laminate composites based on multi-parameter analysis is presented. This model, taken the shear effect as the basis, analyzes the stress and strain of the magnetostrictive and piezoelectric layers by the stress function. The interlayer shear stress and the low-frequency ME response characteristics of ME laminate composites are obtained by using Hamilton principle of minimum energy and in consideration of the influence of stored magnetic field energy of magnetostrictive layer. The theoretical results show that the ME voltage coefficient is related with the magnetic permeability, Poisson ratio, magnetomechanical coupling coefficient, thickness ratio of magnetostrictive material and the Poisson ratio and electromechanical coupling coefficient of piezoelectric material. The influence of these parameters is analyzed. The experimental results show that analytical results are also compared to experimental test data with excellent correlation and their errors are less than 6%.
Communication: Spectroscopic characterization of an alkyl substituted Criegee intermediate syn-CH3CHOO through pure rotational transitions
Authors: Nakajima Masakazu , Endo Yasuki
Published: January 2014

An alkyl-substituted Criegee intermediate syn-CH3CHOO was detected in the gas phase through Fourier-transform microwave spectroscopy. Observed pure rotational transitions show a small splitting corresponding to the A/E components due to the threefold methyl internal rotation. The rotational constants and the barrier height of the hindered methyl rotation were determined to be A = 17 586.5295(15) MHz, B = 7133.4799(41) MHz, C = 5229.1704(40) MHz, and V3 = 837.1(17) cm−1. High-level ab initio calculations which reproduce the experimentally determined values well indicate that the in-plane C–H bond in the methyl moiety is trans to the C–O bond, and other two protons are directed to the terminal oxygen atom for the most stable structure of syn-CH3CHOO. The torsional barrier of the methyl top is fairly large in syn-CH3CHOO, implying a significant interaction between the terminal oxygen and the protons of the methyl moiety, which may be responsible for the high production yields of the OH radical from energized alkyl-substituted Criegee intermediates.
Consideration of a ultracold neutron source in two-dimensional cylindrical geometry by taking simulated boundaries
Authors: Gheisari R. , Firoozabadi M. M. , Mohammadi H.
Published: January 2014

A new idea to calculate ultracold neutron (UCN) production by using Monte Carlo simulation method to calculate the cold neutron (CN) flux and an analytical approach to calculate the UCN production from the simulated CN flux was given. A super-thermal source (UCN source) was modeled based on an arrangement of D2O and solid D2 (sD2). The D2O was investigated as the neutron moderator, and sD2 as the converter. In order to determine the required parameters, a two-dimensional (2D) neutron balance equation written in Matlab was combined with the MCNPX simulation code. The 2D neutron-transport equation in cylindrical (ρ − z) geometry was considered for 330 neutron energy groups in the sD2. The 2D balance equation for UCN and CN was solved using simulated CN flux as boundary value. The UCN source dimensions were calculated for the development of the next UCN source. In the optimal condition, the UCN flux and the UCN production rate (averaged over the sD2 volume) equal to 6.79 × 106 cm−2s−1 and 2.20 ×105 cm−3s−1, respectively.
Phylogenetic analyses of Fusarium graminearum strains from cereals in Italy, and characterisation of their molecular and chemical chemotypes
Authors: Somma S. , Petruzzella A. L. , Logrieco A. F. , Meca G. , Cacciola O. S. , Moretti A.
Published: January 2014

The Fusarium graminearum species complex (FGSC) is a pathogen of durum wheat and other cereals worldwide. The complex consists of at least 15 species that can produce various mycotoxins, including trichothecenes, associated with human and animals toxicoses. In particular, deoxynivalenol (DON), nivalenol (NIV) and their different acetylated derivatives can be produced by the different chemotypes of the complex. In this study, 90 strains, isolated mainly from wheat in Italy and belonging to the FGSC, were assessed for their phylogeny and their chemotype and trichothecene genotype. Almost all strains of the FGSC belonged to F. graminearum sensu stricto, whereas two strains were F. cortaderiae. On the other hand, all three chemotypes, 3ADON, 15ADON and NIV, occurred; 15ADON was the most common molecular chemotype. The data show that the species composition of the Italian FGSC is homogeneous, whereas wide chemotype variability can occur within F. graminearum sensu stricto.
Age and response bias: Evidence from the strength-based mirror effect
Authors: Criss Amy H. , Aue William , Kılıç Aslı
Published: January 2014

Performance in episodic memory is determined both by accurate retrieval from memory and by decision processes. A substantial body of literature suggests slightly poorer episodic memory accuracy for older than younger adults; however, age-related changes in the decision mechanisms in memory have received much less attention. Response bias, the willingness to endorse an item as remembered, is an important decision factor that contributes to episodic memory performance, and therefore understanding age-related changes in response bias is critical to theoretical development. We manipulate list strength in order to investigate two aspects of response bias. First, we evaluate whether criterion placement in episodic memory differs for older and younger adults. Second, we ask whether older adults have the same degree of flexibility to adjust the criterion in response to task demands as younger adults. Participants were tested on weakly and strongly encoded lists where word frequency (Experiment 1) or similarity between targets and foils (Experiment 2) was manipulated. Both older and younger adults had higher hit rates and lower false-alarm rates for strong lists than for weak lists (i.e., a strength-based mirror effect). Older adults were more conservative (less likely to endorse an item as studied) than younger adults, and we found no evidence that older and younger adults differ in their ability to flexibly adjust their criterion based on the demands of the task.
Impact of age-associated increase in 2′-O-methylation of miRNAs on aging and neurodegeneration in Drosophila
Authors: Abe Masashi , Naqvi Ammar , Hendriks Gert-Jan , Feltzin Virzhiniya , Zhu Yongqing , Grigoriev Andrey , Bonini Nancy M.
Published: January 2014

MicroRNAs (miRNAs) are 20- to ∼24-nucleotide (nt) small RNAs that impact a variety of biological processes, from development to age-associated events. To study the role of miRNAs in aging, studies have profiled the levels of miRNAs with time. However, evidence suggests that miRNAs show heterogeneity in length and sequence in different biological contexts. Here, by examining the expression pattern of miRNAs by Northern blot analysis, we found that Drosophila miRNAs show distinct isoform pattern changes with age. Surprisingly, an increase of some miRNAs reflects increased 2′-O-methylation of select isoforms. Small RNA deep sequencing revealed a global increase of miRNAs loaded into Ago2, but not into Ago1, with age. Our data suggest increased loading of miRNAs into Ago2, but not Ago1, with age, indicating a mechanism for differential loading of miRNAs with age between Ago1 and Ago2. Mutations in Hen1 and Ago2, which lack 2′-O-methylation of miRNAs, result in accelerated neurodegeneration and shorter life span, suggesting a potential impact of the age-associated increase of 2′-O-methylation of small RNAs on age-associated processes. Our study highlights that miRNA 2′-O-methylation at the 3′ end is modulated by differential partitioning of miRNAs between Ago1 and Ago2 with age and that this process, along with other functions of Ago2, might impact age-associated events in Drosophila.
CLOCK:BMAL1 is a pioneer-like transcription factor
Authors: Menet Jerome S. , Pescatore Stefan , Rosbash Michael
Published: January 2014

The mammalian circadian clock relies on the master genes CLOCK and BMAL1 to drive rhythmic gene expression and regulate biological functions under circadian control. Here we show that rhythmic CLOCK:BMAL1 DNA binding promotes rhythmic chromatin opening. Mechanisms include CLOCK:BMAL1 binding to nucleosomes and rhythmic chromatin modification; e.g., incorporation of the histone variant H2A.Z. This rhythmic chromatin remodeling mediates the rhythmic binding of other transcription factors adjacent to CLOCK:BMAL1, suggesting that the activity of these other transcription factors contributes to the genome-wide CLOCK:BMAL1 heterogeneous transcriptional output. These data therefore indicate that the clock regulation of transcription relies on the rhythmic regulation of chromatin accessibility and suggest that the concept of pioneer function extends to acute gene regulation.
Targeting of MCL-1 kills MYC-driven mouse and human lymphomas even when they bear mutations in p53
Authors: Kelly Gemma L. , Grabow Stephanie , Glaser Stefan P. , Fitzsimmons Leah , Aubrey Brandon J. , Okamoto Toru , Valente Liz J. , Robati Mikara , Tai Lin , Fairlie W. Douglas , Lee Erinna F. , Lindstrom Mikael S. , Wiman Klas G. , Huang David C.S. , Bouillet Philippe , Rowe Martin , Rickinson Alan B. , Herold Marco J. , Strasser Andreas
Published: January 2014

The transcriptional regulator c-MYC is abnormally overexpressed in many human cancers. Evasion from apoptosis is critical for cancer development, particularly c-MYC-driven cancers. We explored which anti-apoptotic BCL-2 family member (expressed under endogenous regulation) is essential to sustain c-MYC-driven lymphoma growth to reveal which should be targeted for cancer therapy. Remarkably, inducible Cre-mediated deletion of even a single Mcl-1 allele substantially impaired the growth of c-MYC-driven mouse lymphomas. Mutations in p53 could diminish but not obviate the dependency of c-MYC-driven mouse lymphomas on MCL-1. Importantly, targeting of MCL-1 killed c-MYC-driven human Burkitt lymphoma cells, even those bearing mutations in p53. Given that loss of one allele of Mcl-1 is well tolerated in healthy tissues, our results suggest that therapeutic targeting of MCL-1 would be an attractive therapeutic strategy for MYC-driven cancers.
A modular and flexible ESC-based mouse model of pancreatic cancer
Authors: Saborowski Michael , Saborowski Anna , Morris John P. , Bosbach Benedikt , Dow Lukas E. , Pelletier Jerry , Klimstra David S. , Lowe Scott W.
Published: January 2014

Genetically engineered mouse models (GEMMs) have greatly expanded our knowledge of pancreatic ductal adenocarcinoma (PDAC) and serve as a critical tool to identify and evaluate new treatment strategies. However, the cost and time required to generate conventional pancreatic cancer GEMMs limits their use for investigating novel genetic interactions in tumor development and maintenance. To address this problem, we developed flexible embryonic stem cell (ESC)-based GEMMs that facilitate the rapid generation of genetically defined multiallelic chimeric mice without further strain intercrossing. The ESCs harbor a latent Kras mutant (a nearly ubiquitous feature of pancreatic cancer), a homing cassette, and other genetic elements needed for rapid insertion and conditional expression of tetracycline-controlled transgenes, including fluorescence-coupled shRNAs capable of efficiently silencing gene function by RNAi. This system produces a disease that recapitulates the progression of pancreatic cancer in human patients and enables the study and visualization of the impact of gene perturbation at any stage of pancreas cancer progression. We describe the use of this approach to dissect temporal roles for the tumor suppressor Pten and the oncogene c-Myc in pancreatic cancer development and maintenance.
Sensory limitations and the maintenance of colour polymorphisms: viewing the ‘alba’ female polymorphism through the visual system of male Colias butterflies
Authors: Limeri Lisa B. , Morehouse Nathan I.
Published: January 2014

Although colour polymorphisms are a widespread and conspicuous component of extant biodiversity, the selective pressures that act to maintain multiple morphs within populations remain poorly understood in most cases. In particular, the role that visual system limitations may play in maintaining multiple colour morphs is not well explored.

We used a female‐limited colour polymorphism common to the butterfly genus Colias, called the ‘alba’ polymorphism, to investigate the hypotheses that mate‐searching males may struggle to discriminate pale ‘alba’ females from co‐occurring heterospecific white butterflies and/or heterospecific ‘alba’ females, or that ‘alba’ females may be more difficult to detect than non‘alba’ females in natural scenes. Such perceptual limitations may influence the relative mating rates of ‘alba’ versus non‘alba’ females, contributing to the evolutionary persistence of both morphs.

Based on receptor‐noise‐limited modelling of the male Colias visual system, we find that ‘alba’ females exhibit chromatic and luminance contrasts against background foliage that are most similar to the ‘alba’ females of other co‐occurring Colias species and females of the co‐occurring white butterfly Pieris rapae. When compared to other co‐flying butterflies including non‘alba’ females, ‘alba’ females are consistently lower in chromatic contrast against background, but higher in luminance contrast.

When viewed side‐by‐side, we estimate that male Colias should be able to discriminate ‘alba’ females from other co‐occurring heterospecific butterflies, including heterospecific ‘albas’. However, under field conditions that involve larger distances in space or time, males are likely to face challenges discriminating between conspecific ‘alba’ females and co‐occurring heterospecific white butterflies, particularly heterospecific ‘alba’ females.

Our results suggest that constraints arising from male visual function may be involved in the maintenance of this colour polymorphism, particularly in populations that co‐occur with other ‘alba’‐polymorphic Colias species. We argue that such visual system constraints may play a larger role in the maintenance of colour polymorphism than has been empirically appreciated to date.