bluuebunny/crossref_metadata_2025 huggingface dataset:
Practical strategies for identifying groundwater discharges into sediment and surface water with fiber optic temperature measurement
Authors: Selker John , Selker Frank , Huff Julie , Short Russ , Edwards Deborah , Nicholson Peter , Chin Arthur
Published: April 2014

Identifying or ruling out groundwater discharges into sediment and surface waters is often critical for evaluating impacts and for planning remedial actions.
NMR-based dynamics of free glycosaminoglycans in solution
Authors: Pomin Vitor H.
Published: April 2014

Dynamical behaviors of glycosaminoglycans, as here illustrated with a hyaluronan oligosaccharide, are key regulators of biological functions.
Atomic force microscopy-based bioanalysis for the study of disease
Authors: Morton Kirstin C. , Baker Lane A.
Published: April 2014

This review aims to describe the operation of atomic force microscopy related to the study of disease states and single cell analysis, and to serve as an overview of recent advances in this subject area.
Rapid and sensitive gas chromatography-triple quadrupole mass spectrometry method for the determination of organic acids in tobacco leaves
Authors: Lin Shunshun , Zhang Jing , Gao Yahui , Zhang Xiaoming , Song Shiqing , Long Zhangde , Karangwa Eric
Published: April 2014

Gas chromatography-triple quadrupole mass spectrometry method for the determination of organic acids in tobacco leaves..
Stepwise formation of heteronuclear coordination networks based on quadruple-bonded dimolybdenum units containing formamidinate ligands
Authors: Hsu Wayne , Li Yu-Sian , He Hsiu-Yi , Chen Kuan-Ting , Wu Hong-Sheng , Proserpio Davide M. , Chen Jhy-Der , Wang Ju-Chun
Published: April 2014

The first 2D and 3D heteronuclear coordination networks based on quadruple-bonded dimolybdenum units containing formamidinate ligands are reported.
Synthesis of water-soluble β-NaYF4 nanocrystals in a green way
Authors: Tang Chunliang , Wu Qili , Zhuang Jianle , Yang Xianfeng , Wang Jing , Wu Mingmei , Ozin Geoffrey A.
Published: April 2014

Phase pure beta-NaYF4 nanocrystals and transparent UC colloidal solution and thin film could be made in a green way.
Ordered carbon nanotubes–n-dodecyl tetraethylene monoether liquid crystal composites through phase separation induced by poly(ethylene glycol)
Authors: Wang Lin , Xin Xia , Guo Kai , Yang Mengzhou , Ma Xin , Yuan Jing , Shen Jinglin , Yuan Shiling
Published: April 2014

We used a phase separation method to incorporate carbon nanotubes into the lamellar phase of a surfactant.
Pathways of energy transfer in LHCII revealed by room-temperature 2D electronic spectroscopy
Authors: Wells Kym L. , Lambrev Petar H. , Zhang Zhengyang , Garab Gyözö , Tan Howe-Siang
Published: April 2014

We present here the first room-temperature 2D electronic spectroscopy study of energy transfer in the plant light-harvesting complex II, LHCII.
Iron–nitrogen-doped mesoporous tungsten carbide nanostructures as oxygen reduction electrocatalysts
Authors: Moon Je-Suk , Lee Young-Woo , Han Sang-Beom , Kwak Da-Hee , Lee Kyung-Hoon , Park Ah-Reum , Sohn Jung Inn , Cha Seung Nam , Park Kyung-Won
Published: April 2014

WC-m-FT shows excellent electrochemical properties towards the oxygen reduction reaction (ORR) due to the iron and nitrogen species acting as catalytic sites and the mesoporous structure.
Catalytic hydrogenation of CC and CO in unsaturated fatty acid methyl esters
Authors: Hu Chaoquan , Creaser Derek , Siahrostami Samira , Grönbeck Henrik , Ojagh Houman , Skoglundh Magnus
Published: April 2014

Review summarizing recent developments in hydrogenation of CC and CO in FAMEs focusing on catalysts, reaction mechanisms, and reactor conditions.
Ru–NO and Ru–NO2bonding linkage isomerism in cis-[Ru(NO)(NO)(bpy)2]2+/+complexes – a theoretical insight
Authors: Andriani Karla Furtado , Caramori Giovanni Finoto , Doro Fábio Gorzoni , Parreira Renato Luis Tame
Published: April 2014

Calculated energy profile (kcal mol−1) for linkage isomers relative to the ground state structure (GS)1aprior the monoelectronic reduction.
Deprotonation/protonation-driven change of the σ-donor ability of a sulfur atom in iron(ii) complexes with a thioamide SNS pincer type ligand
Authors: Suzuki Tatsuya , Kajita Yuji , Masuda Hideki
Published: April 2014

A new iron complex with a thioamide SNS pincer type ligand, [FeBr2(κ3-H2LDPM)] (κ3-H2LDPM = 2,6-bis(N-2,6-bis(diphenylmethyl)-4-isopropylphenylthioamide)pyridine), was synthesized.
The mechanism of the Cu2+[12-MCCu(Alaha)-4] metallacrown formation and lanthanum(iii) encapsulation
Authors: Beccia Maria R. , García Begoña , García-Tojal Javier , Leal José M. , Secco Fernando , Tegoni Matteo
Published: April 2014

Formation of Cu2+[12-MC-4] metallacrown from Cu(ii) and α-alaninehydroxamic acid involves the Cu2L2+species as the fundamental intermediate. La3+encapsulation, giving La3+[15-MC-5], occurs through the intermediacy of the Cu[12-MC-4]La complex.
Synthesis, crystal structure and photocatalytic properties of an unprecedented arsenic-disubstituted Lindqvist-type peroxopolyoxoniobate ion: {As2Nb4(O2)4O14H1.5}4.5−
Authors: Geng Qiaohua , Liu Qisen , Ma Pengtao , Wang Jingping , Niu Jingyang
Published: April 2014

An unprecedented arsenic-disubstituted Lindqvist-type ion {As2Nb4(O2)4O14H1.5}4.5− which shows a certain photocatalytic water splitting activity has been successfully synthesized and characterized.
The metabolic impact of methamphetamine on the systemic metabolism of rats and potential markers of methamphetamine abuse
Authors: Zheng Tian , Liu Linsheng , Shi Jian , Yu Xiaoyi , Xiao Wenjing , Sun Runbing , Zhou Yahong , Aa Jiye , Wang Guangji
Published: April 2014

The impact analysis and the heatmap revealed the distinct perturbation effect of methamphetamine on endogenous metabolites and the metabolic pathways.
Double-layer CVD graphene as stretchable transparent electrodes
Authors: Won Sejeong , Hwangbo Yun , Lee Seoung-Ki , Kim Kyung-Shik , Kim Kwang-Seop , Lee Seung-Mo , Lee Hak-Joo , Ahn Jong-Hyun , Kim Jae-Hyun , Lee Soon-Bok
Published: April 2014

DLG has a superior electromechanical stretchability compared to SLG owing to strain relaxationviasliding of graphene layers over one another.
Theoretical aspects of WS2 nanotube chemical unzipping
Authors: Kvashnin D. G. , Antipina L. Yu. , Sorokin P. B. , Tenne R. , Golberg D.
Published: April 2014

Theoretical analysis of experimental data on unzipping multilayered WS2 nanotubes by consequent intercalation of lithium atoms and 1-octanethiol molecules [C. Nethravathi, et al., ACS Nano, 2013, 7, 7311] is presented.
Integrating carbon nanotubes into silicon by means of vertical carbon nanotube field-effect transistors
Authors: Li Jingqi , Wang Qingxiao , Yue Weisheng , Guo Zaibing , Li Liang , Zhao Chao , Wang Xianbin , Abutaha Anas I. , Alshareef H. N. , Zhang Yafei , Zhang X. X.
Published: April 2014

Transfer characteristics of the vertical carbon nanotube field-effect transistors depend on the sign of the drain voltage and type of silicon doping.
Ligand effect on the size, valence state and red/near infrared photoluminescence of bidentate thiol gold nanoclusters
Authors: Guevel Xavier Le , Tagit Oya , Rodríguez Carlos E. , Trouillet Vanessa , Pernia Leal Manuel , Hildebrandt Niko
Published: April 2014

Synthesis and characterization of gold nanoclusters (Au NCs) stabilized by a zwitterion ligand (Zw) at different Au : Zw ratios are demonstrated.
Kinetic effects in the photomediated synthesis of silver nanodecahedra and nanoprisms: combined effect of wavelength and temperature
Authors: Wang Haitao , Cui Xiaoqiang , Guan Weiming , Zheng Xianliang , Zhao Hetong , Wang Zhao , Wang Qiyu , Xue Tianyu , Liu Chang , Singh David J. , Zheng Weitao
Published: April 2014

Silver nanoprisms and nanodecahedra with tunable sizes can be synthesized by control of the reaction temperature and the irradiation wavelength.
Convergent and enantioselective syntheses of cytosolic phospholipase A2α inhibiting N-(1-indazol-1-ylpropan-2-yl)carbamates
Authors: Sundermann Tom , Arnsmann Martina , Schwarzkopf Julian , Hanekamp Walburga , Lehr Matthias
Published: April 2014

A convergent synthesis for 4 and enantioselective syntheses for (R)-4 and (S)-4 starting from a (R)-serine derived oxazolidine were developed.
A Pd-catalyzed cascade reaction of N–H insertion and oxidative dehydrogenative aromatization: a new entry to 2-amino-phenols
Authors: Ding Dong , Lv Xiaobing , Li Jian , Qiu Lin , Xu Guangyang , Sun Jiangtao
Published: April 2014

A palladium-catalyzed cascade reaction of N–H insertion and oxidative dehydrogenative aromatization under an air atmosphere has been developed under relatively mild conditions.
19F NMR spectroscopy monitors ligand binding to recombinantly fluorine-labelled b′x from human protein disulphide isomerase (hPDI)
Authors: Curtis-Marof Rose , Doko Denisa , Rowe Michelle L. , Richards Kirsty L. , Williamson Richard A. , Howard Mark J.
Published: April 2014

Fluoroindole recombinant protein labelling enables a 19F NMR study to observe protein–ligand binding and dissociation constant determination.
Trehalose-functionalized block copolymers form serum-stable micelles
Authors: Tale Swapnil R. , Yin Ligeng , Reineke Theresa M.
Published: April 2014

Well-defined amphiphilic diblock terpolymers of poly(ethylene-alt-propylene)–poly[(N,N′-dimethylacrylamide)-grad-poly(6-deoxy-6-methacrylamido trehalose)] (denoted as PEP–poly(DMA-grad-MAT) or PT) have been synthesized using a PEP macromolecular chain transfer agent by reversible addition–fragmentation chain transfer (RAFT) polymerization.
Quinoline and phenanthroline preparation starting from glycerol via improved microwave-assisted modified Skraup reaction
Authors: Saggadi Hanen , Luart Denis , Thiebault Nicolas , Polaert Isabelle , Estel Lionel , Len C.
Published: April 2014

An efficient “green” modified Skraup reaction in neat water was developed using inexpensive, abundant and environmentally-friendly glycerol under microwave irradiation conditions.
Bio-derived CuO nanocatalyst for oxidation of aldehyde: a greener approach
Authors: Tamuly Chandan , Saikia Indranirekha , Hazarika Moushumi , Das Manash R.
Published: April 2014

Eco-friendly synthesis of hierarchical CuO nanoparticles using the peel ofMusa balbisianaand its application as a nanocatalyst in oxidation of aldehyde to the corresponding carboxylic acid is reported here.
Improving the wettability and thermal resistance of polypropylene separators with a thin inorganic–organic hybrid layer stabilized by polydopamine for lithium ion batteries
Authors: Fang Li-Feng , Shi Jun-Li , Jiang Jin-Hong , Li Hao , Zhu Bao-Ku , Zhu Li-Ping
Published: April 2014

A thin inorganic–organic hybrid layer coated polypropylene separator was prepared by a twice immersing process, with improved wettability and thermal resistance.
Davydov splitting in cadmium vacancy emission, ferromagnetism and photosensitivity in manganese incorporated CdS nanocrystals
Authors: Sambandam Balaji , Muthukumar Thangavelu , Arumugam Sonachalam , Paulose P. L. , Manoharan Periakaruppan T.
Published: April 2014

Surfactant and diamines-assisted CdS nanocrystals have Cd2+ vacancies with photoluminescence property. The neighbouring Cd2+–Cd2+ vacancies exhibit Davydov splitting. Addition of Mn2+ ions in these sites leads to ferromagnetism.
Porous acrylate monolith supported Pd nanoparticles: highly active and reusable catalyst for Suzuki–Miyaura reaction in water
Authors: Nandi Mahasweta , Uyama Hiroshi
Published: April 2014

Palladium-Schiff-base functionalized porous methyl methacrylate-glycidyl methacrylate copolymer monoliths can be used for Suzuki–Miyaura reaction of aryl halides in water under aerobic conditions, giving biphenyl products with very high yield and the catalyst can be reused for several reaction cycles without significant loss in its activity.
Size-controlled porous superparamagnetic Zn1/3Fe8/3O4 nanospheres: synthesis, properties and application for drug delivery
Authors: Gao Shengping , Wu Changyu , Jiang Hui , Chen Donghua , Li Qiwei , Liu Xiaoli , Wang Xuemei
Published: April 2014

Magnetic nanospheres have recently attracted much attention in the biomedical areas due to their good biocompatibility and unique magnetic features.
Tuning the surface microstructure and gradient properties of polymers with photopolymerizable polysiloxane-modified nanogels
Authors: Chen Cong , Liu JianCheng , Sun Fang , Stansbury Jeffrey W.
Published: April 2014

Polysiloxane-modified nanogels with self-floating ability can not only reduce polymerization stress, but also spontaneously form a gradient distribution of concentration in the polymerization system, leading to a gradient change in the thermal stability of the polymer. Besides, the increase in polysiloxane content can enhance the self-floating ability.
Vitamin B6cofactor based fluorescent probe for sensing an anion (F−) and cation (Co2+) independently in a pure aqueous medium
Authors: Iniya Murugan , Jeyanthi Dharmaraj , Krishnaveni Karuppiah , Chellappa Duraisamy
Published: April 2014

A new highly selective and sensitive bifunctional fluorescent probe for Co2+and F−ions has been derived from a vitamin B6cofactor and the response mechanism has been analyzed using DFT calculations.
Transformations and reductions of γ-octamolybdates with their monomeric and dimeric amino polycarboxylates
Authors: Chen Quan-Liang , Huang Wei , Chen Mao-Long , Lin Jing , Cao Ze-Xing , Zhou Zhao-Hui
Published: April 2014

Isolated γ-octamolybdate based complexes in solid and solution show that the selection of organic ligands, reductant and synthetic conditions influence the nature of the γ-octamolybdate species, while it preserves its basic structure in different reactions.
Early and late HIV-1 membrane fusion events are impaired by sphinganine lipidated peptides that target the fusion site
Authors: Klug Yoel A. , Ashkenazi Avraham , Viard Mathias , Porat Ziv , Blumenthal Robert , Shai Yechiel
Published: April 2014

Lipid-conjugated peptides have advanced the understanding of membrane protein functions and the roles of lipids in the membrane milieu. These lipopeptides modulate various biological systems such as viral fusion. A single function has been suggested for the lipid, binding to the membrane and thus elevating the local concentration of the peptide at the target site. In the present paper, we challenged this argument by exploring in-depth the antiviral mechanism of lipopeptides, which comprise sphinganine, the lipid backbone of DHSM (dihydrosphingomyelin), and an HIV-1 envelope-derived peptide. Surprisingly, we discovered a partnership between the lipid and the peptide that impaired early membrane fusion events by reducing CD4 receptor lateral diffusion and HIV-1 fusion peptide-mediated lipid mixing. Moreover, only the joint function of sphinganine and its conjugate peptide disrupted HIV-1 fusion protein assembly and folding at the later fusion steps. Via imaging techniques we revealed for the first time the direct localization of these lipopeptides to the virus–cell and cell–cell contact sites. Overall, the findings of the present study may suggest lipid–protein interactions in various biological systems and may help uncover a role for elevated DHSM in HIV-1 and its target cell membranes.
Clinical Aspects Related to Tele-AAC: A Technical Report
Authors: Hall Nerissa , Boisvert Michelle
Published: April 2014

Tele-AAC is a method of service delivery in which professionals provide intervention, assessment, and consultation services through the use of telecommunication technologies to individuals who use augmentative communication systems. In response to the nationwide shortage of highly trained speech-language pathologists, tele-AAC has emerged as a viable way to reach underserved clients. This paper examines the clinical aspects related to tele-AAC, including required and supplementary technology/equipment, resources and personnel needed, training, and quality assurance considerations. In addition, the infrastructure necessary to deliver the range of synchronous and asynchronous tele-AAC services is discussed.
Case Studies for Telepractice in AAC
Authors: Curtis Tanya Rose
Published: April 2014

As the field of telepractice grows, perceived barriers to service delivery must be anticipated and addressed in order to provide appropriate service delivery to individuals who will benefit from this model. When applying telepractice to the field of AAC, additional barriers are encountered when clients with complex communication needs are unable to speak, often present with severe quadriplegia and are unable to position themselves or access the computer independently, and/or may have cognitive impairments and limited computer experience. Some access methods, such as eye gaze, can also present technological challenges in the telepractice environment. These barriers can be overcome, and telepractice is not only practical and effective, but often a preferred means of service delivery for persons with complex communication needs.
The Role of Photographs in Face-to-Face Interactions involving Younger and Older Neurotypical Adults
Authors: Engebretsen Katlyn , Hartman Rachel , Beukelman David , Hux Karen
Published: April 2014

The purpose of this preliminary investigation was to explore the role photographs play in communication interactions involving neurotypical adults. Participants included 10 people from 2 age groups: younger adults between 23 and 25 years of age and older adults between 61 and 74 years of age. Referencing photographs to support one-on-one conversations between an examiner and either a younger or older neurotypical adult speaker occurred approximately 20% of the time. Younger participants relied solely on nonverbal communication in the form of a pointing gesture to convey their intent less than 2% of the time, whereas older participants never relied solely on pointing gestures to convey intent. This suggests that typical speakers treat the referencing of photographs as a supplemental rather than primary communication strategy during face-to-face interactions.
Orbital and spin moments of 5 to 11 nm Fe3O4 nanoparticles measured via x-ray magnetic circular dichroism
Authors: Cai Y. P. , Chesnel K. , Trevino M. , Westover A. , Harrison R. G. , Hancock J. M. , Turley S. , Scherz A. , Reid A. , Wu B. , Graves C. , Wang T. , Liu T. , Dürr H.
Published: April 2014

The orbital and spin contributions to the magnetic moment of Fe in Fe3O4 nanoparticles were measured using X-ray magnetic circular dichroism (XMCD). Nanoparticles of different sizes, ranging from 5 to 11 nm, were fabricated via organic methods and their magnetic behavior was characterized by vibrating sample magnetometry (VSM). An XMCD signal was measured for three different samples at 300 K and 80 K. The extracted values for the orbital and spin contributions to the magnetic moment showed a quenching of the orbital moment and a large spin moment. The calculated spin moments appear somewhat reduced compared to the value expected for bulk Fe3O4. The spin moments measured at 80 K are larger than at 300 K for all the samples, revealing significant thermal fluctuations effects in the nanoparticle assemblies. The measured spin moment is reduced for the smallest nanoparticles, suggesting that the magnetic properties of Fe3O4 nanoparticles could be altered when their size reaches a few nanometers.
Stability of a swirled liquid film entrained by a fast gas stream
Authors: Matas Jean-Philippe , Hong Moongeun , Cartellier Alain
Published: April 2014

We study the liquid flow inside a recessed gas-centered swirl coaxial injector, where a swirled liquid flowing against an outer wall is destabilized by a central fast gas stream. We present measurements of the liquid intact length inside the injector, as a function of swirl number and dynamic pressure ratio. We propose a simple model to account for the effect of these parameters. We next study the surface instability inside the injector: its frequency is measured for several swirl angles, and as a function of gas velocity. Results are first confronted to the predictions of an inviscid linear stability analysis including swirl, and second to the predictions of a viscous linear stability analysis where swirl is not included. The viscous analysis captures the experimental frequency.
Holographic recording and characterization of photorefractive Bi2TeO5 crystals at 633 nm wavelength light
Authors: de Oliveira Ivan , Carvalho Jesiel F. , Fabris Zanine V. , Frejlich Jaime
Published: April 2014

We report on the holographic recording on photorefractive Bi2TeO5 crystals using λ=633 nm wavelength light. We studied the behavior of this material under the action of this low photonic energy light and found out the presence of a fast and a slow hologram, both of photorefractive nature and exhibiting rather high diffraction efficiencies. The faster and the slower holograms are based on the excitation and diffusion of oppositely charged carriers (likely electrons and holes). Relevant parameters for the photoactive centers responsible for both kind of holograms were characterized using purely holographic techniques. No evidences of non-photosensitive ionic charge carriers being involved in the recording process at room temperature nor self-fixing effects were found.
Periodic ordering of clusters and stripes in a two-dimensional lattice model. II. Results of Monte Carlo simulation
Authors: Almarza N. G. , Pȩkalski J. , Ciach A.
Published: April 2014

The triangular lattice model with nearest-neighbor attraction and third-neighbor repulsion, introduced by Pȩkalski, Ciach, and Almarza [J. Chem. Phys. 140, 114701 (2014)] is studied by Monte Carlo simulation. Introduction of appropriate order parameters allowed us to construct a phase diagram, where different phases with patterns made of clusters, bubbles or stripes are thermodynamically stable. We observe, in particular, two distinct lamellar phases—the less ordered one with global orientational order and the more ordered one with both orientational and translational order. Our results concern spontaneous pattern formation on solid surfaces, fluid interfaces or membranes that is driven by competing interactions between adsorbing particles or molecules.
Double threshold ultrasonic distance measurement technique and its application
Authors: Li Weihua , Chen Qiang , Wu Jiangtao
Published: April 2014

The double threshold method realized by hardware circuits and high performance timing chip TDC-GP21 was successfully adapted to solve the key problem of ultrasonic distance measurement, the accurate time-of-flight (TOF) measurement of ultrasonic wave. Compared with other techniques of TOF measurement, the double threshold method presented in this work can suppress noise in the received signal, and achieve a time resolution of around 22 ps and real-time. This method is easy to realize and pertains the advantage of low cost. To compensate temperature and pressure deviations, a temperature measurement module of 10 mK in precision as well as a pressure measurement module of 0.01% in accuracy was developed. The system designed in this work can be exactly used as a two paths ultrasonic gas flowmeter without any adjustment of the hardware circuit. The double threshold method was further corroborated using experiment results of both the ultrasonic distance measurement and ultrasonic gas flow measurement. In distance measurement, the maximum absolute deviation and the maximum relative error are 0.69 mm and 0.28%, respectively, for a target distance range of 100–600 mm. In flow measurement, the maximum absolute deviation and the worst repeatability are 1.16% and 0.65% for a flow in the range of 50–700 m3/h.
Self-healing dynamics of surfactant coatings on thin viscous films
Authors: Strickland Stephen L. , Hin Matthew , Sayanagi M. Richard , Gaebler Cameron , Daniels Karen E. , Levy Rachel
Published: April 2014

We investigate the dynamics of an insoluble surfactant on the surface of a thin viscous fluid spreading inward to fill a surfactant-free region. During the initial stages of surfactant self-healing, Marangoni forces drive an axisymmetric ridge inward to coalesce into a growing central distension; this is unlike outward spreading, in which the ridge only decays. In later dynamics, the distension slowly decays and the surfactant concentration equilibrates. We present results from experiments in which we simultaneously measure the surfactant concentration (using fluorescently tagged lipids) and the fluid height profile (via laser profilometry). We compare the results to simulations of a mathematical model using parameters from our experiments. For surfactant concentrations close to but below the critical monolayer concentration, we observe agreement between the height profiles in the numerical simulations and the experiment, but disagreement in the surfactant distribution. In experiments at lower concentrations, the surfactant spreading and formation of a Marangoni ridge are no longer present, and a persistent lipid-free region remains. This observation, which is not captured by the simulations, has undesirable implications for applications where uniform coverage is advantageous. Finally, we probe the generality of the effect, and find that distensions of similar size are produced independent of initial fluid thickness, size of initial clean region, and surfactant type.
Design and characterization of electron beam focusing for X-ray generation in novel medical imaging architecture
Authors: Bogdan Neculaes V. , Zou Yun , Zavodszky Peter , Inzinna Louis , Zhang Xi , Conway Kenneth , Caiafa Antonio , Frutschy Kristopher , Waters William , De Man Bruno
Published: April 2014

A novel electron beam focusing scheme for medical X-ray sources is described in this paper. Most vacuum based medical X-ray sources today employ a tungsten filament operated in temperature limited regime, with electrostatic focusing tabs for limited range beam optics. This paper presents the electron beam optics designed for the first distributed X-ray source in the world for Computed Tomography (CT) applications. This distributed source includes 32 electron beamlets in a common vacuum chamber, with 32 circular dispenser cathodes operated in space charge limited regime, where the initial circular beam is transformed into an elliptical beam before being collected at the anode. The electron beam optics designed and validated here are at the heart of the first Inverse Geometry CT system, with potential benefits in terms of improved image quality and dramatic X-ray dose reduction for the patient.
Behavior of a particle-laden flow in a spiral channel
Authors: Lee Sungyon , Stokes Yvonne , Bertozzi Andrea L.
Published: April 2014

Spiral gravity separators are devices used in mineral processing to separate particles based on their specific gravity or size. The spiral geometry allows for the simultaneous application of gravitational and centripetal forces on the particles, which leads to segregation of particles. However, this segregation mechanism is not fundamentally understood, and the spiral separator literature does not tell a cohesive story either experimentally or theoretically. While experimental results vary depending on the specific spiral separator used, present theoretical works neglect the significant coupling between the particle dynamics and the flow field. Using work on gravity-driven monodisperse slurries on an incline that empirically accounts for this coupling, we consider a monodisperse particle slurry of small depth flowing down a rectangular channel that is helically wound around a vertical axis. We use a thin-film approximation to derive an equilibrium profile for the particle concentration and fluid depth and find that, in the steady state limit, the particles concentrate towards the vertical axis of the helix, leaving a region of clear fluid.
Constructing polyatomic potential energy surfaces by interpolating diabatic Hamiltonian matrices with demonstration on green fluorescent protein chromophore
Authors: Park Jae Woo , Rhee Young Min
Published: April 2014

Simulating molecular dynamics directly on quantum chemically obtained potential energy surfaces is generally time consuming. The cost becomes overwhelming especially when excited state dynamics is aimed with multiple electronic states. The interpolated potential has been suggested as a remedy for the cost issue in various simulation settings ranging from fast gas phase reactions of small molecules to relatively slow condensed phase dynamics with complex surrounding. Here, we present a scheme for interpolating multiple electronic surfaces of a relatively large molecule, with an intention of applying it to studying nonadiabatic behaviors. The scheme starts with adiabatic potential information and its diabatic transformation, both of which can be readily obtained, in principle, with quantum chemical calculations. The adiabatic energies and their derivatives on each interpolation center are combined with the derivative coupling vectors to generate the corresponding diabatic Hamiltonian and its derivatives, and they are subsequently adopted in producing a globally defined diabatic Hamiltonian function. As a demonstration, we employ the scheme to build an interpolated Hamiltonian of a relatively large chromophore, para-hydroxybenzylidene imidazolinone, in reference to its all-atom analytical surface model. We show that the interpolation is indeed reliable enough to reproduce important features of the reference surface model, such as its adiabatic energies and derivative couplings. In addition, nonadiabatic surface hopping simulations with interpolation yield population transfer dynamics that is well in accord with the result generated with the reference analytic surface. With these, we conclude by suggesting that the interpolation of diabatic Hamiltonians will be applicable for studying nonadiabatic behaviors of sizeable molecules.
Positron annihilation study for enhanced nitrogen-vacancy center formation in diamond by electron irradiation at 77 K
Authors: Tang Z. , Chiba T. , Nagai Y. , Inoue K. , Toyama T. , Hasegawa M.
Published: April 2014

A compact ensemble of high density nitrogen-vacancy (NV) centers in diamond is essential to sense various external fields with a high precision at the nanoscale. Here, defects in type IIa and type Ib diamonds induced by 28 MeV electron irradiation at 77 K were studied by combining the positron annihilation spectroscopy and first-principles calculations. It is shown that the electron irradiation at 77 K can significantly enhance the NV center formation by directly converting 24% vacancies into the NV centers, indicating that it is an efficient way to produce the high density NV centers in the type Ib diamond.
On the mechanical performance and deformation of nanotwinned Ag
Authors: Furnish T. A. , Hodge A. M.
Published: April 2014

In this study, the mechanical performance and deformation behavior of various nano-twinned Ag foils were evaluated under two deformation modes. It was generally observed that the addition of nanotwins led to an enhanced strength, but the overall plastic flow and ductility decreased. Using a bimodal distribution of nanotwinned and non-nanotwinned grains was shown to be a possible route for overcoming this limitation. Specifically, some strengthening was observed which can be attributed to the nanotwinned grains, while the ductility was attributed to the contribution from non-nanotwinned grains. The overall deformation behavior is presented and discussed in terms of the nanotwin volume fraction.
Effects of ion abundances on electromagnetic ion cyclotron wave growth rate in the vicinity of the plasmapause
Authors: Henning F. D. , Mace R. L.
Published: April 2014

Electromagnetic ion cyclotron (EMIC) waves in multi-ion species plasmas propagate in branches. Except for the branch corresponding to the heaviest ion species, which has only a resonance at its gyrofrequency, these branches are bounded below by a cutoff frequency and above by a resonant gyrofrequency. The condition for wave growth is determined by the thermal anisotropies of each ion species, j, which sets an upper bound, ωj∗, on the wave frequency below which that ion species contributes positively to the growth rate. It follows that the relative positions of the cutoffs and the critical frequencies ωj∗ play a crucial role in determining whether a particular wave branch will be unstable. The effect of the magnetospheric ion abundances on the growth rate of each branch of the EMIC instability in a model where all the ion species have kappa velocity distributions is investigated by appealing to the above ideas. Using the variation of the cutoff frequencies predicted by cold plasma theory as a guide, optimal ion abundances that maximise the EMIC instability growth rate are sought. When the ring current is comprised predominantly of H+ ions, all branches of the EMIC wave are destabilised, with the proton branch having the maximum growth rate. When the O+ ion abundance in the ring current is increased, a decrease in the growth rate of the proton branch and cyclotron damping of the helium branch are observed. The oxygen branch, on the other hand, experiences an increase in the maximum growth rate with an increase in the O+ ion abundance. When the ring current is comprised predominantly of He+ ions, only the helium and oxygen branches of the EMIC wave are destabilised, with the helium branch having the maximum growth rate.
Edge transport studies in the edge and scrape-off layer of the National Spherical Torus Experiment with Langmuir probes
Authors: Boedo J. A. , Myra J. R. , Zweben S. , Maingi R. , Maqueda R. J. , Soukhanovskii V. A. , Ahn J. W. , Canik J. , Crocker N. , D'Ippolito D. A. , Bell R. , Kugel H. , Leblanc B. , Roquemore L. A. , Rudakov D. L. ,   NSTX Team
Published: April 2014

Transport and turbulence profiles were directly evaluated using probes for the first time in the edge and scrape-off layer (SOL) of NSTX [Ono et al., Nucl. Fusion 40, 557 (2000)] in low (L) and high (H) confinement, low power (Pin∼ 1.3 MW), beam-heated, lower single-null discharges. Radial turbulent particle fluxes peak near the last closed flux surface (LCFS) at ≈4×1021 s−1 in L-mode and are suppressed to ≈0.2×1021 s−1 in H mode (80%–90% lower) mostly due to a reduction in density fluctuation amplitude and of the phase between density and radial velocity fluctuations. The radial particle fluxes are consistent with particle inventory based on SOLPS fluid modeling. A strong intermittent component is identified. Hot, dense plasma filaments 4–10 cm in diameter, appear first ∼2 cm inside the LCFS at a rate of ∼1×1021 s−1 and leave that region with radial speeds of ∼3–5 km/s, decaying as they travel through the SOL, while voids travel inward toward the core. Profiles of normalized fluctuations feature levels of 10% inside LCFS to ∼150% at the LCFS and SOL. Once properly normalized, the intermittency in NSTX falls in similar electrostatic instability regimes as seen in other devices. The L-H transition causes a drop in the intermittent filaments velocity, amplitude and number in the SOL, resulting in reduced outward transport away from the edge and a less dense SOL.
Detailed numerical investigation of 90∘ scattering of energetic particles interacting with magnetic turbulence
Authors: Qin G. , Shalchi A.
Published: April 2014

In the present paper, we re-visit a well-known problem in diffusion theory, namely the 90∘ scattering problem. We use a test-particle code to compute the pitch-angle Fokker-Planck coefficient at 90∘ for different values of the turbulent magnetic field strength and the magnetic rigidity. We consider a slab model and compare our numerical findings with the analytical result provided by second-order quasilinear theory. We show that the latter theory accurately describes 90∘ scattering. We also replace the slab model by a more realistic two-component model to explore the influence of the turbulence model on 90∘ scattering.
Design and experimental investigations of a smart battery energy storage system for frequency control in microgrids
Authors: Serban I. , Marinescu C.
Published: April 2014

The frequency control process and ensuring the security of supply in microgrids (MG) with high penetration of renewable energy sources demand the development of specific control systems and energy storage resources. This paper presents a three-phase battery energy storage system (BESS), designed to support the frequency in autonomous MG. Besides the basic functions, the proposed BESS includes enhanced features, which improves the MG frequency response. When placing the BESS near a consumer, which may also include small generators, the local power variations can be partially or totally compensated, thus relieving the MG of these perturbations. The proposed solution is experimentally evaluated within a laboratory MG prototype and with a 5 kW BESS.
Advances in instrumentation for nuclear astrophysics
Authors: Pain S. D.
Published: April 2014

The study of the nuclear physics properties which govern energy generation and nucleosynthesis in the astrophysical phenomena we observe in the universe is crucial to understanding how these objects behave and how the chemical history of the universe evolved to its present state. The low cross sections and short nuclear lifetimes involved in many of these reactions make their experimental determination challenging, requiring developments in beams and instrumentation. A selection of developments in nuclear astrophysics instrumentation is discussed, using as examples projects involving the nuclear astrophysics group at Oak Ridge National Laboratory. These developments will be key to the instrumentation necessary to fully exploit nuclear astrophysics opportunities at the Facility for Rare Isotope Beams which is currently under construction.
Rate of false conviction of criminal defendants who are sentenced to death
Authors: Gross Samuel R. , O’Brien Barbara , Hu Chen , Kennedy Edward H.
Published: April 2014

Significance

The rate of erroneous conviction of innocent criminal defendants is often described as not merely unknown but unknowable. We use survival analysis to model this effect, and estimate that if all death-sentenced defendants remained under sentence of death indefinitely at least 4.1% would be exonerated. We conclude that this is a conservative estimate of the proportion of false conviction among death sentences in the United States.
Juvenile hormone regulates body size and perturbs insulin signaling in
Drosophila
Authors: Mirth Christen Kerry , Tang Hui Yuan , Makohon-Moore Sasha C. , Salhadar Samy , Gokhale Rewatee H. , Warner Raechel D. , Koyama Takashi , Riddiford Lynn M. , Shingleton Alexander W.
Published: April 2014

Significance

Understanding how organisms regulate their body size is a fundamental problem in biology. Body size regulation involves the careful integration of mechanisms that control growth rate with those that control growth duration. In insects, developmental hormones such as juvenile hormone and ecdysone regulate developmental transitions and growth duration. The conserved insulin-signaling pathway regulates growth rates. Our studies reveal an intimate link between the three, whereby juvenile hormone controls body size by regulating ecdysone synthesis, which in turn modifies insulin signaling. In vertebrates, hormones such as androgens and estrogens interact with insulin signaling to influence tumor growth. By studying the developmental context of hormone interactions, our data reveal fundamental features of body size regulation that have important consequences for understanding cancer growth.
Projected changes in African easterly wave intensity and track in response to greenhouse forcing
Authors: Skinner Christopher Bryan , Diffenbaugh Noah S.
Published: April 2014

Significance

African easterly waves (AEWs) are ubiquitous weather disturbances over the tropical Atlantic basin during the summer season. However, despite the critical influence of AEWs on Sahel rainfall, transport of Saharan dust, and initiation of Atlantic hurricanes, little is known about how global warming influences AEW activity. We use an ensemble of general circulation models to investigate the response of AEWs to elevated greenhouse gas concentrations. We find that increases in regional temperature gradients and the strength of convergence and uplift along the Intertropical Front of Africa lead to increases in the strength of AEWs. Given the relationships that are observed in the current climate, changes in AEW strength could influence climate over both West Africa and the larger Atlantic basin.
Drosha as an interferon-independent antiviral factor
Authors: Shapiro Jillian S. , Schmid Sonja , Aguado Lauren C. , Sabin Leah R. , Yasunaga Ari , Shim Jaehee V. , Sachs David , Cherry Sara , tenOever Benjamin R.
Published: April 2014

Significance

Virus infections must be combated at a cellular level. The strategies used to inhibit virus differ dramatically when comparing plants and insects to mammals. Here, we identify an evolutionary conserved antiviral response that is independent of these known defenses. We demonstrate that an RNA nuclease called Drosha is repurposed during virus infection to cleave viral RNA and modulate the cellular environment as a means of inhibiting virus replication.
Arabidopsis
ABCG14 is essential for the root-to-shoot translocation of cytokinin
Authors: Ko Donghwi , Kang Joohyun , Kiba Takatoshi , Park Jiyoung , Kojima Mikiko , Do Jihye , Kim Kyung Yoon , Kwon Mi , Endler Anne , Song Won-Yong , Martinoia Enrico , Sakakibara Hitoshi , Lee Youngsook
Published: April 2014

Significance

Roots and shoots communicate with each other to synchronize and optimize plant growth and respond to environmental changes. Shoots and roots exchange signals to sense the status and respond to the needs of the other organ. Cytokinins, which are phytohormones that regulate various aspects of growth and development, are recognized as the most important signal transmitted from roots to shoots. Whereas the enzymes underlying cytokinin biosynthesis and the corresponding receptors have been identified, our knowledge of cytokinin transport is limited. In this study, we identified the
Arabidopsis
ATP-binding cassette transporter subfamily G14 as a major component in the transfer of cytokinins from roots to shoots and hence as a regulator of shoot development. This finding represents a major breakthrough in the field.
TRIM65 regulates microRNA activity by ubiquitination of TNRC6
Authors: Li Shitao , Wang Lingyan , Fu Bishi , Berman Michael A. , Diallo Alos , Dorf Martin E.
Published: April 2014

Significance

MicroRNAs (miRNAs) comprise a large family of small RNA molecules that regulate gene expression in diverse biological pathways of both plants and animals. We used a combination of proteomic and functional analyses of proteins associated with the miRNA pathway to identify the ubiquitin E3 ligase tripartite motif 65 (TRIM65) and five other genes implicated in regulation of miRNA activity in human cells. Biochemical analysis established that TRIM65 forms stable complexes with trinucleotide repeat containing six (TNRC6) proteins and that these molecules colocalize in processing body-like structures. Gain of function and RNAi analyses reveal that TRIM65 regulates miRNA-driven suppression of mRNA translation by targeting TNRC6 proteins for ubiquitination and degradation. Thus, TRIM65 represents a new negative regulator of miRNA activity.
UNC93B1 is essential for the plasma membrane localization and signaling of Toll-like receptor 5
Authors: Huh Ji-Won , Shibata Takuma , Hwang Misun , Kwon Eun-Hye , Jang Min Seong , Fukui Ryutaro , Kanno Atsuo , Jung Da-Jung , Jang Myoung Ho , Miyake Kensuke , Kim You-Me
Published: April 2014

Significance

Toll-like receptors (TLRs) are key innate immune receptors that sense pathogen- or danger-associated molecules. The members of the TLR family can be classified into two groups based on their subcellular localization patterns—cell surface vs. endolysosomes—but how individual TLR is targeted to its destination is largely unknown. UNC93B1 was regarded to specifically bind the endolysosomal TLRs in the endoplasmic reticulum and deliver them to endolysosomes with no role for the surface-localized TLRs. In this study, we demonstrate that TLR5, a cell surface receptor for bacterial protein flagellin, also binds UNC93B1 and requires it for plasma membrane localization and signaling, thus revealing a previously unappreciated role of UNC93B1 in the regulation of the TLR family.
Extracortical origin of some murine subplate cell populations
Authors: Pedraza María , Hoerder-Suabedissen Anna , Albert-Maestro María Amparo , Molnár Zoltán , De Carlos Juan A.
Published: April 2014

Significance

Early-generated subplate cells play important roles in development of the cerebral cortex. Although it has been assumed that most subplate cells are generated in the cortical germinative zone, here we describe an alternative site of neurogenesis, the rostromedial telencephalic wall. The rostromedial telencephalic wall gives rise to both subplate projection neurons and GABAergic interneurons. Both populations migrate tangentially to the cortex and strongly express the Lpar1-eGFP transgene. This unusual extracortical source of subplate projection neurons and interneurons is challenging the currently accepted scheme of cortical development.
Histone demethylase KDM5B is a key regulator of genome stability
Authors: Li Xin , Liu Ling , Yang Shangda , Song Nan , Zhou Xing , Gao Jie , Yu Na , Shan Lin , Wang Qian , Liang Jing , Xuan Chenghao , Wang Yan , Shang Yongfeng , Shi Lei
Published: April 2014

Significance

DNA double-strand breaks are generally repaired in the context of highly organized chromatin. However, how epigenetic mechanisms are involved in the maintenance of the genetic fidelity remains poorly understood. Here we report that lysine-specific histone demethylase 5B (KDM5B), a well-defined transcriptional repressor, promotes double-strand break signaling and is required for efficient DNA repairs. We demonstrated that KDM5B, in doing so, functions to orchestrate checkpoint activation and cell survival after DNA damage. Our results provide evidence to indicate that KDM5B is an important genome caretaker and a critical regulator of genome stability.
Large, stratified, and mechanically functional human cartilage grown in vitro by mesenchymal condensation
Authors: Bhumiratana Sarindr , Eton Ryan E. , Oungoulian Sevan R. , Wan Leo Q. , Ateshian Gerard A. , Vunjak-Novakovic Gordana
Published: April 2014

Significance

The ability to regenerate functional cartilage from adult human mesenchymal stem cells would have tremendous clinical impact. Despite significant efforts, mechanically functional human cartilage has not been grown in vitro. We report engineering of functional human cartilage from mesenchymal stem cells, by mimicking the physiologic developmental process of mesenchymal cell condensation. Condensed mesenchymal bodies were induced to fuse and form mechanically functional cartilaginous tissue interfacing with bone, without using a scaffolding material. We demonstrate that this simple “biomimetic” approach can be used to generate centimeter-sized, anatomically shaped pieces of human cartilage with physiologic stratification and mechanical properties. Functional human cartilage grown from a patient’s own cells using this method could greatly accelerate the development of new therapeutic modalities for cartilage repair.
Transcription factor E93 specifies adult metamorphosis in hemimetabolous and holometabolous insects
Authors: Ureña Enric , Manjón Cristina , Franch-Marro Xavier , Martín David
Published: April 2014

Significance

Transformation from immature to a fully reproductive adult form is an essential process during the development of higher organisms. In insects, transition from juvenile to adult stages is triggered by the decline of the juvenile hormone, but the molecular mechanisms underlying the dramatic morphological and physiological changes remain poorly understood. Here, we report that a single factor, E93, controls juvenile-to-adult transition in hemimetabolous and holometabolous insects, thus acting as the universal adult specifier in winged insects. Interestingly, we find that E93 not only promotes adult metamorphosis but also represses the expression of the antimetamorphic genes
Krüppel-homolog 1
and
Broad-Complex
, ensuring the proper juvenile–adult transition. This study represents a significant step toward defining the molecular mechanisms underlying insect metamorphosis.