bluuebunny/crossref_metadata_2025 huggingface dataset:
Improving the secretion of cadaverine in Corynebacterium glutamicum by cadaverine–lysine antiporter
Authors: Li Ming , Li Dongxia , Huang Yunyan , Liu Meng , Wang Hongxin , Tang Qi , Lu Fuping
Published: February 2014

Cadaverine (1,5-pentanediamine, diaminopentane), the desired raw material of bio-polyamides, is an important industrial chemical with a wide range of applications. Biosynthesis of cadaverine in Corynebacterium glutamicum has been a competitive way in place of petroleum-based chemical synthesis method. To date, the cadaverine exporter has not been found in C. glutamicum. In order to improve cadaverine secretion, the cadaverine–lysine antiporter CadB from Escherichia coli was studied in C. glutamicum. Fusion expression of cadB and green fluorescent protein (GFP) gene confirmed that CadB could express in the cell membrane of C. glutamicum. Co-expression of cadB and ldc from Hafnia alvei in C. glutamicum showed that the cadaverine secretion rate increased by 22 % and the yield of total cadaverine and extracellular cadaverine increased by 30 and 73 %, respectively. Moreover, the recombinant strain cultured at acid and neutral pH separately hardly had any difference in cadaverine concentrations. These results suggested that CadB could be expressed in the cell membrane of C. glutamicum and that recombinant CadB could improve cadaverine secretion and the yield of cadaverine. Moreover, the pH value did not affect the function of recombinant CadB. These results may be a promising metabolic engineering strategy for improving the yield of the desired product by enhancing its export out of the cell.
Inhibition of NAD+-dependent histone deacetylases (sirtuins) causes growth arrest and activates both apoptosis and autophagy in the pathogenic protozoan Trypanosoma cruzi
Authors: VEIGA-SANTOS PHERCYLES , REIGNAULT LISSA CATHERINE , HUBER KILIAN , BRACHER FRANZ , DE SOUZA WANDERLEY , DE CARVALHO TECIA MARIA ULISSES
Published: February 2014

Chagas disease, which is caused by the parasite Trypanosoma cruzi, affects approximately 7–8 million people in Latin America. The drugs available to treat this disease are ineffective against chronic phase disease and are associated with toxic side effects. Therefore, the development of new compounds that can kill T. cruzi at low concentrations is critically important. Herein, we report the effects of a novel 3-arylideneindolin-2-one that inhibits sirtuins, which are highly conserved proteins that are involved in a variety of physiological processes. The compound KH-TFMDI was tested against the epimastigote, trypomastigote and amastigote forms of T. cruzi, and its effects were evaluated using flow cytometry, light and electron microscopy. KH-TFMDI inhibited the replication of T. cruzi intracellular amastigotes with an IC50 of 0·5±0·2 μm, which is significantly lower than the IC50 of benznidazole. The compound also lysed the highly infectious bloodstream trypomastigotes (BST) with LC50 values of 0·8±0·3 μm at 4 °C and 2·5±1·1 μm at 37 °C. KH-TFMDI inhibited cytokinesis and induced several morphological changes in the parasite, leading to its death by apoptosis and autophagy. This study highlights sirtuins as a potential new target for Chagas disease therapy.
X-ray refinement significantly underestimates the level of microscopic heterogeneity in biomolecular crystals
Authors: Kuzmanic Antonija , Pannu Navraj S. , Zagrovic Bojan
Published: February 2014

Biomolecular X-ray structures typically provide a static, time- and ensemble-averaged view of molecular ensembles in crystals. In the absence of rigid-body motions and lattice defects, B-factors are thought to accurately reflect the structural heterogeneity of such ensembles. In order to study the effects of averaging on B-factors, we employ molecular dynamics simulations to controllably manipulate microscopic heterogeneity of a crystal containing 216 copies of villin headpiece. Using average structure factors derived from simulation, we analyse how well this heterogeneity is captured by high-resolution molecular-replacement-based model refinement. We find that both isotropic and anisotropic refined B-factors often significantly deviate from their actual values known from simulation: even at high 1.0 Å resolution andRfreeof 5.9%, B-factors of some well-resolved atoms underestimate their actual values even sixfold. Our results suggest that conformational averaging and inadequate treatment of correlated motion considerably influence estimation of microscopic heterogeneity via B-factors, and invite caution in their interpretation.
Bifacial dye-sensitized solar cells: A strategy to enhance overall efficiency based on transparent polyaniline electrode
Authors: Wu Jihuai , Li Yan , Tang Qunwei , Yue Gentian , Lin Jianming , Huang Miaoliang , Meng Lijian
Published: February 2014

Dye-sensitized solar cell (DSSC) is a promising solution to global energy and environmental problems because of its clean, low-cost, high efficiency, good durability and easy fabrication. However, enhancing the efficiency of the DSSC still is an important issue. Here we devise a bifacial DSSC based on a transparent polyaniline (PANI) counter electrode (CE). Owing to the sunlight irradiation simultaneously from the front and the rear sides, more dye molecules are excited and more carriers are generated, which results in the enhancement of short-circuit current density and therefore overall conversion efficiency. The photoelectric properties of PANI can be improved by modifying with 4-aminothiophenol (4-ATP). The bifacial DSSC with 4-ATP/PANI CE achieves a light-to-electric energy conversion efficiency of 8.35%, which is increased by ~24.6% compared to the DSSC irradiated from the front only. This new concept along with promising results provides a new approach for enhancing the photovoltaic performances of solar cells.
Role of Ge:As ratio in controlling the light-induced response of a-GexAs35−xSe65 thin films
Authors: Khan Pritam , Jain H. , Adarsh K. V.
Published: February 2014

In this paper, we present interesting results on the quantification of photodarkening (PD), photobleaching (PB) and transient PD (TPD) in a-GexAs35−xSe65 thin films as a function of network rigidity. Composition dependent light-induced responses of these samples indicate that there exist two parallel competing mechanisms of instantaneous PD arising from the As part of the network and PB arising from the Ge part of the network. Raman spectra of the as-prepared and illuminated samples provide first direct evidence of the light-induced structural changes: an increase in AsSe3/2 pyramidal and GeSe4/2 corner-sharing tetrahedra units together with new Ge-O bond formation and decrease in energetically unstable edge sharing GeSe4/2 tetrahedra. Importantly, for a fixed Se concentration, Ge:As ratio plays the critical role in controlling the net light-induced response rather than the much believed rigidity of the glassy network.
A quenched binuclear ruthenium(ii) dimer activated by another photosensitizer
Authors: Lou Kun , Lovell Jonathan F.
Published: February 2014

A binuclear ruthenium(ii) dimer (BiRD) bridged by an alkene linker was synthesized that was labile to reactive oxygen species generated by another photosensitizer.
Halocarbocyclization versus dihalogenation: substituent directed iodine(iii) catalyzed halogenations
Authors: Stodulski Maciej , Goetzinger Alissa , Kohlhepp Stefanie V. , Gulder Tanja
Published: February 2014

A catalyst-dependent halogenation reactivity was observed leading to the development of a mild and efficient iodine(iii) catalyzed dihalogenation method.
Enhanced adsorption of carbon nanocomposites exhausted with 2,4-dichlorophenoxyacetic acid after regeneration by thermal oxidation and microwave irradiation
Authors: Dichiara Anthony B. , Benton-Smith Jordan , Rogers Reginald E.
Published: February 2014

The ability of raw and recycled graphene nanoplatelets–single-walled carbon nanotubes hybrid papers for 2,4-dichlorophenoxyacetic acid adsorption from aqueous solutions was evaluated.
Influence of different types of natural organic matter on titania nanoparticle stability: effects of counter ion concentration and pH
Authors: Gallego-Urrea Julián A. , Perez Holmberg Jenny , Hassellöv Martin
Published: February 2014

Effects of pH, three natural macromolecules and three mono- and divalent electrolytes on the stability of titania nanoparticles.
Visualizing tilted binding and precession of diatomic NO adsorbed to Co-porphyrin on Au(111) using scanning tunneling microscopy
Authors: Kim Howon , Chang Yun Hee , Lee Soon-Hyeong , Lim Soobin , Noh Seung-Kyun , Kim Yong-Hyun , Kahng Se-Jong
Published: February 2014

By considering tilted binding and precession motion of NO, we explained the bright ring shapes observed in scanning tunneling microscopy of NO–Co-porphyrin on Au(111), with our density functional theory calculations.
Joining forces: integrating the mechanical and optical single molecule toolkits
Authors: Jacobs Monique J. , Blank Kerstin
Published: February 2014

Combining single molecule force measurements with fluorescence detection opens up exciting new possibilities for the characterization of mechanoresponsive molecules in Biology and Materials Science.
Ratiometric delivery of cisplatin and doxorubicin using tumour-targeting carbon-nanotubes entrapping platinum(iv) prodrugs
Authors: Chin Chee Fei , Yap Siew Qi , Li Jian , Pastorin Giorgia , Ang Wee Han
Published: February 2014

A hydrophobic platinum(iv) prodrug was entrapped in tumour-targeting multiwalled carbon nanotubes for synchronous and ratiometric delivery of drug combinations.
Inhibition of the 4Fe–4S proteins IspG and IspH: an EPR, ENDOR and HYSCORE investigation
Authors: Guerra Francisco , Wang Ke , Li Jikun , Wang Weixue , Liu Yi-Liang , Amin Shivani , Oldfield Eric
Published: February 2014

EPR investigations reveal remarkably diverse inhibitor binding modes for IspG and IspH, drug targets in the non-mevalonate pathway.
Strongest π–metal orbital coupling in a porphyrin/gold cluster system
Authors: Tanaka Daisuke , Inuta Yoko , Sakamoto Masanori , Furube Akihiro , Haruta Mitsutaka , So Yeong-Gi , Kimoto Koji , Hamada Ikutaro , Teranishi Toshiharu
Published: February 2014

π–Metal coupling in a porphyrin/gold cluster system at the closest distance was investigated spectroscopically; this system formed an exciplex in the excited state.
Luminescence of triarylphosphines and their application to detection of elemental chlorine in aqueous solution
Authors: Natarajan Palani
Published: February 2014

The concept of aggregation induced emission has been utilized to raise the luminescence of triarylphosphines for the first time.
TAGS-related indium compounds and their thermoelectric properties – the solid solution series (GeTe)xAgInySb1−yTe2 (x = 1–12; y = 0.5 and 1)
Authors: Schröder Thorsten , Rosenthal Tobias , Giesbrecht Nadja , Maier Stefan , Scheidt Ernst-Wilhelm , Scherer Wolfgang , Snyder G. Jeffrey , Schnick Wolfgang , Oeckler Oliver
Published: February 2014

Solid solutions of GeTe, AgInTe2 and optionally AgSbTe2 (accessible via high-pressure synthesis or by quenching, depending on the phases’ In content) exhibit remarkable thermoelectric properties that clearly reflect transitions between metastable and stable phases.
Chronic oral administration of Ang-(1–7) improves skeletal muscle, autonomic and locomotor phenotypes in muscular dystrophy
Authors: Sabharwal Rasna , Cicha Michael Z. , Sinisterra Ruben D. M. , De Sousa Frederico B. , Santos Robson A. , Chapleau Mark W.
Published: February 2014

Muscular dystrophies are a group of heterogeneous genetic disorders that cause progressive muscle weakness and wasting, dilated cardiomyopathy and early mortality. There are different types of muscular dystrophies with varying aetiologies but they all have a common hallmark of myofibre degeneration, atrophy and decreased mobility. Mutation in Sgcd (sarcoglycan-δ), a subunit of dystrophin glycoprotein complex, causes LGMD2F (limb girdle muscular dystrophy 2F). Previously, we have reported that Sgcd-deficient (Sgcd−/−) mice exhibit AngII (angiotensin II)-induced autonomic and skeletal muscle dysfunction at a young age, which contributes to onset of dilated cardiomyopathy and mortality at older ages. Two counter-regulatory RAS (renin–angiotensin system) pathways have been identified: deleterious actions of AngII acting on the AT1R (AngII type 1 receptor) compared with the protective actions of Ang-(1–7) [angiotensin-(1–7)] acting on the receptor Mas. We propose that the balance between the AngII/AT1R and Ang-(1–7)/Mas axes is disturbed in Sgcd−/− mice. Control C57BL/6J and Sgcd−/− mice were treated with Ang-(1–7) included in hydroxypropyl β-cyclodextrin (in drinking water) for 8–9 weeks beginning at 3 weeks of age. Ang-(1–7) treatment restored the AngII/AT1R compared with Ang-(1–7)/Mas balance, decreased oxidative stress and fibrosis in skeletal muscle, increased locomotor activity, and prevented autonomic dysfunction without lowering blood pressure in Sgcd−/− mice. Our results suggest that correcting the early autonomic dysregulation by administering Ang-(1–7) or enhancing its endogenous production may provide a novel therapeutic approach in muscular dystrophy.
Algorithmic Approaches to Hemostasis Testing
Authors: Kottke-Marchant Kandice
Published: February 2014

There are many unique issues that may make a pathologist's consultation helpful in hemostasis testing. Besides the rapidly expanding knowledge of both bleeding and thrombotic disorders and a wide test menu, hemostasis testing is very sensitive to preanalytical issues (hemolysis, fill volume, time, temperature, storage conditions) and the interference of many commonly prescribed drugs. The pathologist can serve an important role in the evaluation of a patient for a bleeding or thrombotic disorder. Using defined algorithms, hemostasis testing can proceed in a logical fashion and be reported using patient-specific comments that take into account clinical history and medication therapy. This approach can improve the diagnostic process, preventing misdiagnoses and leading to a decreased time to diagnosis and an improved utilization of laboratory resources.
High-throughput gated photon counter with two detection windows programmable down to 70 ps width
Authors: Boso Gianluca , Tosi Alberto , Mora Alberto Dalla , Zappa Franco
Published: February 2014

We present the design and characterization of a high-throughput gated photon counter able to count electrical pulses occurring within two well-defined and programmable detection windows. We extensively characterized and validated this instrument up to 100 Mcounts/s and with detection window width down to 70 ps. This instrument is suitable for many applications and proves to be a cost-effective and compact alternative to time-correlated single-photon counting equipment, thanks to its easy configurability, user-friendly interface, and fully adjustable settings via a Universal Serial Bus (USB) link to a remote computer.
Position sensitive detection of neutrons in high radiation background field
Authors: Vavrik D. , Jakubek J. , Pospisil S. , Vacik J.
Published: February 2014

We present the development of a high-resolution position sensitive device for detection of slow neutrons in the environment of extremely high γ and e− radiation background. We make use of a planar silicon pixelated (pixel size: 55 × 55 μm2) spectroscopic Timepix detector adapted for neutron detection utilizing very thin 10B converter placed onto detector surface. We demonstrate that electromagnetic radiation background can be discriminated from the neutron signal utilizing the fact that each particle type produces characteristic ionization tracks in the pixelated detector. Particular tracks can be distinguished by their 2D shape (in the detector plane) and spectroscopic response using single event analysis. A Cd sheet served as thermal neutron stopper as well as intensive source of gamma rays and energetic electrons. Highly efficient discrimination was successful even at very low neutron to electromagnetic background ratio about 10−4.
Plasma tomographic reconstruction from tangentially viewing camera with background subtraction
Authors: Odstrčil M. , Mlynář J. , Weinzettl V. , Háček P. , Odstrčil T. , Verdoolaege G. , Berta M. , Szabolics T. , Bencze A.
Published: February 2014

Light reflections are one of the main and often underestimated issues of plasma emissivity reconstruction in visible light spectral range. Metallic and other specular components of tokamak generate systematic errors in the optical measurements that could lead to wrong interpretation of data. Our analysis is performed at data from the tokamak COMPASS. It is a D-shaped tokamak with specular metallic vessel and possibility of the H-mode plasma. Data from fast visible light camera were used for tomographic reconstruction with background reflections subtraction to study plasma boundary. In this article, we show that despite highly specular tokamak wall, it is possible to obtain a realistic reconstruction. The developed algorithm shows robust results despite of systematic errors in the optical measurements and calibration. The motivation is to obtain an independent estimate of the plasma boundary shape.
Semi-automatic laboratory goniospectrometer system for performing multi-angular reflectance and polarization measurements for natural surfaces
Authors: Sun Z. Q. , Wu Z. F. , Zhao Y. S.
Published: February 2014

In this paper, the design and operation of the Northeast Normal University Laboratory Goniospectrometer System for performing multi-angular reflected and polarized measurements under controlled illumination conditions is described. A semi-automatic arm, which is carried on a rotated circular ring, enables the acquisition of a large number of measurements of surface Bidirectional Reflectance Factor (BRF) over the full hemisphere. In addition, a set of polarizing optics enables the linear polarization over the spectrum from 350 nm to 2300 nm. Because of the stable measurement condition in the laboratory, the BRF and linear polarization has an average uncertainty of 1% and less than 5% depending on the sample property, respectively. The polarimetric accuracy of the instrument is below 0.01 in the form of the absolute value of degree of linear polarization, which is established by measuring a Spectralon plane. This paper also presents the reflectance and polarization of snow, soil, sand, and ice measured during 2010–2013 in order to illustrate its stability and accuracy. These measurement results are useful to understand the scattering property of natural surfaces on Earth.
A high-precision mechanical absolute-rotation sensor
Authors: Venkateswara Krishna , Hagedorn Charles A. , Turner Matthew D. , Arp Trevor , Gundlach Jens H.
Published: February 2014

We have developed a mechanical absolute-rotation sensor capable of resolving ground rotation angle of less than 1 nrad\documentclass[12pt]{minimal}\begin{document}$/\sqrt{\text{Hz}}$\end{document}/Hz above 30 mHz and 0.2 nrad\documentclass[12pt]{minimal}\begin{document}$/\sqrt{\text{Hz}}$\end{document}/Hz above 100 mHz about a single horizontal axis. The device consists of a meter-scale beam balance, suspended by a pair of flexures, with a resonance frequency of 10.8 mHz. The center of mass is located 3 μm above the pivot, giving an excellent horizontal displacement rejection of better than 3 × 10−5 rad/m. The angle of the beam is read out optically using a high-sensitivity autocollimator. We have also built a tiltmeter with better than 1 nrad\documentclass[12pt]{minimal}\begin{document}$/\sqrt{\text{Hz}}$\end{document}/Hz sensitivity above 30 mHz. Co-located measurements using the two instruments allowed us to distinguish between background rotation signal at low frequencies and intrinsic instrument noise. The rotation sensor is useful for rotational seismology and for rejecting background rotation signal from seismometers in experiments demanding high levels of seismic isolation, such as Advanced Laser Interferometer Gravitational-wave Observatory.
Nd3+ doped LaF3 nanoparticles as self-monitored photo-thermal agents
Authors: Rocha Uéslen , Upendra Kumar K. , Jacinto Carlos , Ramiro Julio , Caamaño Antonio J. , García Solé José , Jaque Daniel
Published: February 2014

In this work, we demonstrate how LaF3 nanoparticles activated with large concentrations (up to 25%) of Nd3+ ions can simultaneously operate as biologically compatible efficient nanoheaters and fluorescent nanothermometers under single beam (808 nm) infrared laser excitation. Nd3+:LaF3 nanoparticles emerge as unique multifunctional agents that could constitute the first step towards the future development of advanced platforms capable of simultaneous deep tissue fluorescence bio-imaging and controlled photo-thermal therapies.
Magnetocaloric effect in GdCoxAl2−x system for (0.15 ≤ x ≤ 1) compositions
Authors: Fu H. , Hadimani R. L. , Ma Z. , Wang M. X. , Teng B. H. , Jiles D. C.
Published: February 2014

Structure and magnetic properties of the GdAl2-GdCo2 system including magnetocaloric effect have been investigated for various compositions. The as-cast GdCoxAl2-x alloys prepared by arc-melting crystallize in the dual-phase structure of cubic MgCu2-type and hexagonal MgZn2-type phases. All the as-cast dual-phase alloys exhibit only one magnetic phase transition near 77 K even though two ferrimagnetic phases coexist. The magnetic transition was broadened by the continuous transitions of the component phases, which resulted in enhancement of relative cooling power at the expense of the magnetic entropy changes.
Flory-Huggins parameter χ, from binary mixtures of Lennard-Jones particles to block copolymer melts
Authors: Chremos Alexandros , Nikoubashman Arash , Panagiotopoulos Athanassios Z.
Published: February 2014

In this contribution, we develop a coarse-graining methodology for mapping specific block copolymer systems to bead-spring particle-based models. We map the constituent Kuhn segments to Lennard-Jones particles, and establish a semi-empirical correlation between the experimentally determined Flory-Huggins parameter χ and the interaction of the model potential. For these purposes, we have performed an extensive set of isobaric–isothermal Monte Carlo simulations of binary mixtures of Lennard-Jones particles with the same size but with asymmetric energetic parameters. The phase behavior of these monomeric mixtures is then extended to chains with finite sizes through theoretical considerations. Such a top-down coarse-graining approach is important from a computational point of view, since many characteristic features of block copolymer systems are on time and length scales which are still inaccessible through fully atomistic simulations. We demonstrate the applicability of our method for generating parameters by reproducing the morphology diagram of a specific diblock copolymer, namely, poly(styrene-b-methyl methacrylate), which has been extensively studied in experiments.
Structural defects in epitaxial graphene layers synthesized on C-terminated 4H-SiC (0001¯) surface—Transmission electron microscopy and density functional theory studies
Authors: Borysiuk J. , Sołtys J. , Piechota J. , Krukowski S. , Baranowski J. M. , Stępniewski R.
Published: February 2014

The principal structural defects in graphene multilayers synthesized on the carbon-terminated face of a 4H-SiC (0001¯) substrate were investigated using the high-resolution transmission electron microscopy. The analyzed systems include a wide variety of defected structures such as edge dislocations, rotational multilayers, and grain boundaries. It was shown that graphene layers are composed of grains of the size of several nanometres or larger; they differ in a relative rotation by large angles, close to 30°. The structure of graphene multilayers results from the synthesis on a SiC (0001¯) surface, which proceeds via intensive nucleation of new graphene layers that coalesce under various angles creating an immense orientational disorder. Structural defects are associated with a built-in strain resulting from a lattice mismatch between the SiC substrate and the graphene layers. The density functional theory data show that the high-angular disorder of AB stacked bi-layers is not restoring the hexagonal symmetry of the lattice.
Anomalous diffusion with transient subordinators: A link to compound relaxation laws
Authors: Stanislavsky Aleksander , Weron Karina , Weron Aleksander
Published: February 2014

This paper deals with a problem of transient anomalous diffusion which is currently found to emerge from a wide range of complex processes. The nonscaling behavior of such phenomena reflects changes in time-scaling exponents of the mean-squared displacement through time domain – a more general picture of the anomalous diffusion observed in nature. Our study is based on the identification of some transient subordinators responsible for transient anomalous diffusion. We derive the corresponding fractional diffusion equation and provide links to the corresponding compound relaxation laws supported by this case generalizing many empirical dependencies well-known in relaxation investigations.
Zr/oxidized diamond interface for high power Schottky diodes
Authors: Traoré A. , Muret P. , Fiori A. , Eon D. , Gheeraert E. , Pernot J.
Published: February 2014

High forward current density of 103 A/cm2 (at 6 V) and a breakdown field larger than 7.7 MV/cm for diamond diodes with a pseudo-vertical architecture, are demonstrated. The power figure of merit is above 244 MW/cm2 and the relative standard deviation of the reverse current density over 83 diodes is 10% with a mean value of 10−9 A/cm2. These results are obtained with zirconium as Schottky contacts on the oxygenated (100) oriented surface of a stack comprising an optimized lightly boron doped diamond layer on a heavily boron doped one, epitaxially grown on a Ib substrate. The origin of such performances are discussed.
System analysis of force feedback microscopy
Authors: Rodrigues Mario S. , Costa Luca , Chevrier Joël , Comin Fabio
Published: February 2014

It was shown recently that the Force Feedback Microscope (FFM) can avoid the jump-to-contact in Atomic force Microscopy even when the cantilevers used are very soft, thus increasing force resolution. In this letter, we explore theoretical aspects of the associated real time control of the tip position. We take into account lever parameters such as the lever characteristics in its environment, spring constant, mass, dissipation coefficient, and the operating conditions such as controller gains and interaction force. We show how the controller parameters are determined so that the FFM functions at its best and estimate the bandwidth of the system under these conditions.
Fabrication of a single layer graphene by copper intercalation on a SiC(0001) surface
Authors: Yagyu Kazuma , Tajiri Takayuki , Kohno Atsushi , Takahashi Kazutoshi , Tochihara Hiroshi , Tomokage Hajime , Suzuki Takayuki
Published: February 2014

Cu atoms deposited on a zero layer graphene grown on a SiC(0001) substrate, intercalate between the zero layer graphene and the SiC substrate after the thermal annealing above 600 °C, forming a Cu-intercalated single layer graphene. On the Cu-intercalated single layer graphene, a graphene lattice with superstructure due to moiré pattern is observed by scanning tunneling microscopy, and specific linear dispersion at the K¯ point as well as a characteristic peak in a C1s core level spectrum, which is originated from a free-standing graphene, is confirmed by photoemission spectroscopy. The Cu-intercalated single layer graphene is found to be n-doped.
The M-band transmission flux of the plastic foil with a coated layer of silicon or germanium
Authors: Li Liling , Zhang Lu , Jiang Shaoen , Guo Liang , Qing Bo , Li Zhichao , Zhang Jiyan , Yang Jiamin , Ding Yongkun
Published: February 2014

Silicon (Si) and Germanium (Ge) can be used as the dopant in the ablator material for the purpose of reducing preheating in indirect-drive inertial confinement fusion. Their performances in reducing preheating are quite different. A method to evaluate the difference of these two kinds of dopants has been presented in this letter. In the Shenguang-II high power laser facility, the M-band (1.6–4.4 keV) transmission flux of Si-coated plastic (CH) and Ge-coated plastic (CH) has been measured by using the M-band x-ray diode. In the experiment, we find that the Si-coated CH can absorb more M-band x-rays and thus reduce the preheating of the fuel in our experiment condition. By using the radiation hydrodynamic code MULTI-1D, we got the simulation result which was well suited for the experiment. The comparison of their opacities (Te = 60–100 eV and ρ = 0.1–0.5 g/cm3) also shows that the opacity of Si is higher than that of Ge almost in the whole range of 1.6–4.4 keV.
A generalized magnetic refrigeration scheme
Authors: Tamura Ryo , Ohno Takahisa , Kitazawa Hideaki
Published: February 2014

We have investigated the magnetocaloric effects in antiferromagnets and compared them with those in ferromagnets using Monte Carlo simulations. In antiferromagnets, the magnetic entropy reaches a maximum value at a finite magnetic field when the temperature is fixed below the Néel temperature. Using the fact, we proposed a protocol for applying magnetic fields to achieve the maximum efficiency for magnetic refrigeration in antiferromagnets. In particular, we found that at low temperatures, antiferromagnets are more useful for magnetic refrigeration than ferromagnets.
Photoconductive organic crystals grown on planar substrates with electrode effects
Authors: Li Hongwei , Zhang Xinping , Zu Wenbo
Published: February 2014

Organic polycrystalline fibers were grown onto planar substrates from solution of N,N-bis(1-ethylpropyl)-3,4,9,10-perylenebis(dicarboximide) (EPPTC) in chloroform through π-stacking. Devices with excellent photoconductivity have been achieved by depositing aluminum electrodes on the top surface of the crystal fibers with a gap width as large as 180 μm. This implies excellent π-stacking of EPPTC molecules in a long range through crystallization. Strong excitation-wavelength dependence was observed for the photoconductive performance of these crystal fibers. Dispersion in the transmission spectrum of the aluminum electrodes is taken as the mechanisms to address the wavelength-dependent photoconductivity of EPPTC polycrystalline fibers.
Photocarrier dynamics in anatase TiO2 investigated by pump-probe absorption spectroscopy
Authors: Matsuzaki H. , Matsui Y. , Uchida R. , Yada H. , Terashige T. , Li B.-S. , Sawa A. , Kawasaki M. , Tokura Y. , Okamoto H.
Published: February 2014

The dynamics of photogenerated electrons and holes in undoped anatase TiO2 were studied by femtosecond absorption spectroscopy from the visible to mid-infrared region (0.1–2.0 eV). The transient absorption spectra exhibited clear metallic responses, which were well reproduced by a simple Drude model. No mid-gap absorptions originating from photocarrier localization were observed. The reduced optical mass of the photocarriers obtained from the Drude-model analysis is comparable to theoretically expected one. These results demonstrate that both photogenerated holes and electrons act as mobile carriers in anatase TiO2. We also discuss scattering and recombination dynamics of photogenerated electrons and holes on the basis of the time dependence of absorption changes.
Nonlinear multiferroic phase shifters for microwave frequencies
Authors: Ustinov Alexey B. , Kalinikos Boris A. , Srinivasan G.
Published: February 2014

A nonlinear microwave phase shifter based on a planar multiferroic composite has been studied. The multiferroic structure is fabricated in the form of a bilayer consisting of yttrium iron garnet and barium strontium titanate. The principle of operation of the device is based on the linear and nonlinear control of the phase shift of the hybrid spin-electromagnetic waves propagating in the bilayer. The linear control is realized with magnetic and electric fields. The nonlinear control is provided by the input power of microwave signal. The device showed a nonlinear phase shift up to 250°, electric field induced phase shift up to 330°, and magnetic field induced phase shift of more than 180°.
Channeling of electron transport to improve collection efficiency in mesoporous titanium dioxide dye sensitized solar cell stacks
Authors: Fakharuddin Azhar , Ahmed Irfan , Khalidin Zulkeflee , Yusoff Mashitah M. , Jose Rajan
Published: February 2014

Dye-sensitized solar cell (DSC) modules are generally made by interconnecting large photoelectrode strips with optimized thickness (∼14 μm) and show lower current density (JSC) compared with their single cells. We found out that the key to achieving higher JSC in large area devices is optimized photoelectrode volume (VD), viz., thickness and area which facilitate the electron channeling towards working electrode. By imposing constraints on electronic path in a DSC stack, we achieved >50% increased JSC and ∼60% increment in photoelectric conversion efficiency in photoelectrodes of similar VD (∼3.36 × 10−4 cm3) without using any metallic grid or a special interconnections.
Electric field induced metastable ferroelectric phase and its behavior in (Pb, La)(Zr, Sn, Ti)O3 antiferroelectric single crystal near morphotropic phase boundary
Authors: Li Yuanyuan , Cao Wenwu , Li Qiang , Yan Qingfeng , Gao Jinghan , Zhuo Fangping , Xi Xiaoqing , Zhang Yiling , Chu Xiangcheng
Published: February 2014

Antiferroelectric (AFE) (Pb, La)(Zr, Sn, Ti)O3 (PLZST) single crystal with composition near morphotropic phase boundary has been grown and studied. X-ray diffraction analysis and electrical properties reveal coexistence of antiferroelectric/ferroelectric (FE) phases, with the AFE phase dominated at room temperature. Temperature-dependent polarization and strain measurements indicate that the AFE phase can be induced into a metastable FE phase by electric field. The FE phase can be maintained in a wide temperature range above room temperature and recovers to AFE phase around a critical temperature of 90 °C, accompanied with remarkable change in field-induced strain. The strain at 90 °C (∼0.50%) is ten times larger than that at room temperature (∼0.04%), which makes the PLZST single crystal a promising candidate for thermal switch and actuator application.
Phosphorus vacancy cluster model for phosphorus diffusion gettering of metals in Si
Authors: Chen Renyu , Trzynadlowski Bart , Dunham Scott T.
Published: February 2014

In this work, we develop models for the gettering of metals in silicon by high phosphorus concentration. We first performed ab initio calculations to determine favorable configurations of complexes involving phosphorus and transition metals (Fe, Cu, Cr, Ni, Ti, Mo, and W). Our ab initio calculations found that the P4V cluster, a vacancy surrounded by 4 nearest-neighbor phosphorus atoms, which is the most favorable inactive P species in heavily doped Si, strongly binds metals such as Cu, Cr, Ni, and Fe. Based on the calculated binding energies, we build continuum models to describe the P deactivation and Fe gettering processes with model parameters calibrated against experimental data. In contrast to previous models assuming metal-P1V or metal-P2V as the gettered species, the binding of metals to P4V satisfactorily explains the experimentally observed strong gettering behavior at high phosphorus concentrations.
Quantum key distribution for 10 Gb/s dense wavelength division multiplexing networks
Authors: Patel K. A. , Dynes J. F. , Lucamarini M. , Choi I. , Sharpe A. W. , Yuan Z. L. , Penty R. V. , Shields A. J.
Published: February 2014

We demonstrate quantum key distribution (QKD) with bidirectional 10 Gb/s classical data channels in a single fiber using dense wavelength division multiplexing. Record secure key rates of 2.38 Mbps and fiber distances up to 70 km are achieved. Data channels are simultaneously monitored for error-free operation. The robustness of QKD is further demonstrated with a secure key rate of 445 kbps over 25 km, obtained in the presence of data lasers launching conventional 0 dBm power. We discuss the fundamental limit for the QKD performance in the multiplexing environment.
Thermal conductivity of nano-layered systems due to surface phonon-polaritons
Authors: Ordonez-Miranda Jose , Tranchant Laurent , Chalopin Yann , Antoni Thomas , Volz Sebastian
Published: February 2014

The effective thermal conductivity of a layered system due to the propagation of surface phonon-polaritons is studied. We analytically demonstrate that the thermal conductivity of a set of nanolayers can be described as one of a single layer with an effective permittivity, which does not ordinarily appear in nature and depends on the permittivities and thicknesses of the individual components. For a two-layer system of SiO2 and BaF2 surrounded by air, it is shown that: (i) the propagation length of surfaces phonon-polaritons can be as high as 3.3 cm for a 200 nm-thick system. (ii) The thermal conductivity of the system with total thickness of 50 nm is 3.4 W/m·K, which is twice that of a single layer of SiO2, at 500 K. Higher values are found for higher temperatures and thinner layers. The results show that an ensemble of layers provides more channels than a single layer for the propagation of surface phonon-polaritons and therefore for the enhancement of the thermal conductivity of common polar materials.
High field nuclear magnetic resonance in transition metal substituted BaFe2As2
Authors: Garitezi T. M. , Lesseux G. G. , Rosa P. F. S. , Adriano C. , Reyes A. P. , Kuhns P. L. , Pagliuso P. G. , Urbano R. R.
Published: February 2014

We report high field 75As nuclear magnetic resonance (NMR) measurements on Co and Cu substituted BaFe2As2 single crystals displaying same structural/magnetic transition T0≃128  K. From our anisotropy studies in the paramagnetic state, we strikingly found virtually identical quadrupolar splitting and consequently the quadrupole frequency νQ≃2.57(1)  MHz for both compounds, despite the claim that each Cu delivers 2 extra 3d electrons in BaFe2As2 compared to Co substitution. These results allow us to conclude that a subtle change in the crystallographic structure, particularly in the Fe–As tetrahedra, must be the most probable tuning parameter to determine T0 in this class of superconductors rather than electronic doping. Furthermore, our NMR data around T0 suggest coexistence of tetragonal/paramagnetic and orthorhombic/antiferromagnetic phases between the structural and the spin density wave magnetic phase transitions, similarly to what was reported for K-doped BaFe2As2 [Urbano et al., Phys. Rev. Lett. 105, 107001 (2010)].
Uncooled photodetectors based on CdSe nanocrystals with an interdigital metallization
Authors: Nusir A. I. , Aguilar J. , Bever Z. , Manasreh M. O.
Published: February 2014

Uncooled photodetectors fabricated from CdSe nanocrystals with an interdigital metallization are investigated in the visible-near-infrared spectral region. A device with 5 μm interdigital spacing possesses a dark current on the order of 10−11 A while the photocurrent is measured to be five orders of magnitude higher than the dark current. The room temperature detectivity extracted from the photocurrent and dark current is estimated to be on the order of 3.5 x 1010 cmHz1/2 W−1 at 5 V bias voltage. The spectral response was measured with an onset at 710 nm, which is in good agreement with the photoluminescence spectra obtained from the nanocrystals.
Breast‐feeding Duration and Gluten Introduction Among Mothers With Celiac Disease
Authors: Welander Adina , Montgomery Scott , Ludvigsson Johnny , Ludvigsson Jonas F.
Published: February 2014

Objectives:

Both breast‐feeding duration and age at gluten introduction have been implicated in the pathogenesis of celiac disease (CD). We hypothesized that parental CD affects the feeding pattern of the offspring, mediated by parental health awareness increasing adherence to infant feeding guidelines.

Methods:

Prospectively collected infant feeding data were obtained through the All Babies in Southeast Sweden study. Information regarding infant feeding was available in 9414 children. Twenty‐two mothers had a history of biopsy‐verified CD before delivery of a child in the study, and 9392 mothers had no diagnosis of CD before birth and thus constituted the unexposed or control population. Cox regression was used to compare the risk of early weaning and gluten introduction according to parental CD status, and logistic regression to assess whether mothers with CD were more likely to breast‐feed their children at gluten introduction.

Results:

Some 63% of children were breast‐fed for at least 9 months. We found no association between maternal CD and early weaning (adjusted hazard ratio [HR] 1.0, 95% confidence interval [CI] 0.6–1.7), or between paternal CD and early weaning (HR 0.5, 95% CI 0.1–1.9). Sixty percent of children were introduced to gluten in months 5 and 6. Maternal CD was not associated with age at gluten introduction (adjusted HR 0.8, 95% CI 0.6–1.3). There was no statistically significant association between maternal CD and breast‐feeding at the time of gluten introduction (odds ratio 1.4, 95% CI 0.4–4.7).

Conclusions:

Feeding patterns do not seem to vary between offspring and mothers with CD and those without.
Broadly tuned and respiration-independent inhibition in the olfactory bulb of awake mice
Authors: Cazakoff Brittany N. , Lau Billy Y. B. , Crump Kerensa L. , Demmer Heike S. , Shea Stephen D.
Published: February 2014

Olfactory representations are shaped by both brain state and respiration; however, the interaction and circuit substrates of these influences are poorly understood. Granule cells (GCs) in the main olfactory bulb (MOB) are presumed to sculpt activity that reaches the olfactory cortex via inhibition of mitral/tufted cells (MTs). GCs may potentially sparsen ensemble activity by facilitating lateral inhibition among MTs, and/or they may enforce temporally-precise activity locked to breathing. Yet, the selectivity and temporal structure of GC activity during wakefulness are unknown. We recorded GCs in the MOB of anesthetized and awake mice and reveal pronounced state-dependent features of odor coding and temporal patterning. Under anesthesia, GCs exhibit sparse activity and are strongly and synchronously coupled to the respiratory cycle. Upon waking, GCs desynchronize, broaden their odor responses, and typically fire without regard for the respiratory rhythm. Thus during wakefulness, GCs exhibit stronger odor responses with less temporal structure. Based on these observations, we propose that during wakefulness GCs likely predominantly shape MT odor responses through broadened lateral interactions rather than respiratory synchronization.
Phase‐rectified signal averaging for intrapartum electronic fetal heart rate monitoring is related to acidaemia at birth
Authors: Georgieva A , Papageorghiou AT , Payne SJ , Moulden M , Redman CWG
Published: February 2014

Objective

Recent studies suggest that phase‐rectified signal averaging (PRSA), measured in antepartum fetal heart rate (FHR) traces, may sensitively indicate fetal status; however, its value has not been assessed during labour. We determined whether PRSA relates to acidaemia in labour, and compare its performance to short‐term variation (STV), a related computerised FHR feature.

Design

Historical cohort.

Setting

Large UK teaching hospital.

Population

All 7568 Oxford deliveries that met the study criteria from April 1993 to February 2008.

Methods

We analysed the last 30 minutes of the FHR and associated outcomes of infants. We used computerised analysis to calculate PRSA decelerative capacity (DCPRSA), and its ability to predict umbilical arterial blood pH ≤ 7.05 using receiver operator characteristic (ROC) curves and event rate estimates (EveREst). We compared DCPRSA with STV calculated on the same traces.

Main outcome measure

Umbilical arterial blood pH ≤ 7.05.

Results

We found that PRSA could be measured in all cases. DCPRSA predicted acidaemia significantly better than STV: the area under the ROC curve was 0.665 (95% CI 0.632–0.699) for DCPRSA, and 0.606 (0.573–0.639) for STV (P = 0.007). EveREst plots showed that in the worst fifth centile of cases, the incidence of low pH was 17.75% for DCPRSA but 11.00% for STV (P < 0.001). DCPRSA was not highly correlated with STV.

Conclusions

DCPRSA of the FHR can be measured in labour, and appears to predict acidaemia more accurately than STV. Further prospective evaluation is warranted to assess whether this could be clinically useful. The weak correlation between DCPRSA and STV suggests that they could be combined in multivariate FHR analyses.
Evaluation of the Microbial Safety of Child Food of Animal Origin in Greece
Authors: Liandris Emmanouil , Gazouli Maria , Taka Styliani , Andreadou Margarita , Vaiopoulou Anna , Tzimotoudis Nikolaos , Kasampalidis Ioannis , Mpaseas Dionysis , Fyliousis George , Poltrionieri Palmiro , Cook Nigel , Ikonomopoulos John
Published: February 2014

Foodborne illness is a major cause of morbidity and mortality especially for children, even in the developed world. The aim of this study was to assess the microbial safety of food of animal origin intended for consumption by children in Greece. Sampling involved 8 categories of retail products and was completed with a collection of 850 samples. These were tested by PCR and/or culture forListeria monocytogenes,Campylobacterspp.,Escherichia coliO157,Salmonellaspp.,Cronobacter sakazakii,Brucellaspp., andMycobacterium aviumsubspparatuberculosis(MAP). The number of positive results recorded collectively for the pathogens under investigation over the total number of samples tested was 3.52% and 0.12% by PCR and culture, respectively. The most frequently detected pathogen was enterohemorrhagicE. coli(1.29%) followed byBrucella(0.82%) andListeria(0.82%). DNA belonging to MAP was detected in 0.35% of samples, which was also the percentage of positivity recorded forCampylobacter. The percentage forSalmonellawas 0.12%. It can be concluded from the results that there is no indication of noncompliance for the tested food samples. However, detection of DNA belonging to pathogens that are transmissible to humans through food is indicative that constant vigilance regarding food safety is an absolute necessity.
Rich analysis and rational models: inferring individual behavior from infant looking data
Authors: Piantadosi Steven T. , Kidd Celeste , Aslin Richard
Published: February 2014

Studies of infant looking times over the past 50 years have provided profound insights about cognitive development, but their dependent measures and analytic techniques are quite limited. In the context of infants' attention to discrete sequential events, we show how a Bayesian data analysis approach can be combined with a rational cognitive model to create a rich data analysis framework for infant looking times. We formalize (i) a statistical learning model, (ii) a parametric linking between the learning model's beliefs and infants' looking behavior, and (iii) a data analysis approach and model that infers parameters of the cognitive model and linking function for groups and individuals. Using this approach, we show that recent findings from Kidd, Piantadosi and Aslin () of a U‐shaped relationship between look‐away probability and stimulus complexity even holds within infants and is not due to averaging subjects with different types of behavior. Our results indicate that individual infants prefer stimuli of intermediate complexity, reserving attention for events that are moderately predictable given their probabilistic expectations about the world.