bluuebunny/crossref_metadata_2025 huggingface dataset:
Radar Observations of Comet Nuclei and Comae
Authors: Campbell Donald B. , Harmon John K. , Nolan Micael C. , Ostro Steven J.
Published: March 2016

Nine comets have been detected with either the Arecibo (12.6 cm wavelength) or Goldstone (3.5 cm) radar systems. Included are six nucleus detections and five detections of echoes from coma grains. The radar backscatter cross sections measured for the nuclei correlate well with independent estimates of their sizes and are indicative of surface densities in the range of 0.5 to 1.0 g cm-3. Like most asteroids, comets appear to have surfaces that are very rough at scales much larger than the radar wavelength. Coma echo models can explain the radar cross sections using grain size distributions that include a substantial population of cm-sized grains. A long term goal of the cometary radar program has been the high resolution imaging of a cometary nucleus. Eleven short period comets are potentially detectable over the next two decades a few of which may be suitable for imaging. We are always waiting for the arrival of a new comet with an orbit that brings it within 0.1 AU of the earth.
High-Resolution Optical Observations of Interstellar Absorption Lines
Authors: Welty Daniel E.
Published: March 2016

We briefly note several current topics concerning the properties of interstellar clouds for which high-resolution optical spectra play a significant role: (1) the recognition and characterization of small-scale (sub-pc) structure in both atomic and molecular gas; (2) the discovery of variations in the 7Li/6Li isotopic ratio in the nearby Galactic ISM; (3) the determination of atomic and molecular abundances and physical conditions for heavily reddened (“translucent”) Galactic sightlines; and (4) studies of interstellar clouds in the LMC and SMC.
The Deuterium Balmer Series
Authors: Hébrard Guillaume
Published: March 2016

The first detection and identification of deuterium Balmer lines were recently reported in H ii regions, using high spectral resolution data secured at CFHT and VLT. The Di lines appear as faint, narrow emission features in the blue wings of the H i Balmer lines and can be distinguished from high-velocity Hi emission. The identification as deuterium and the excitation mechanism as fluorescence are both established beyond doubt. The deuterium Balmer series might lead to a new, optical method of deuterium abundance measurement in the interstellar medium. This may be the only way to observe atomic deuterium in objects like the Magellanic Clouds or low metallicity blue compact galaxies.
Probing Physics and Chemistry in Circumnuclear Torus with OH
Authors: Zhi-yao Yu
Published: March 2016

We observed OH maser emission at 18cm in a circumnuclear torus surrounding the center of IRAS10173+0828 using the 7 telescopes of MERLIN, together with the Lovell antenna. IRAS10173+0828 is a distant super-luminous far-infrared galaxy. The OH maser emission is remarkably narrow (FWHP = 39km s_1) for its strength, and the 1667 and 1665 MHz lines are well separated. The 1667 transition shows two distinct peaks displaced from one another by 100 km s−1. Using our MERLIN observational results we probe the physics in the circumnuclear torus surrounding the center of IRAS10173+0828, obtain the kinematic properties of the torus, and study the central source.
Newly detected H2O Masers in Seyfert and Starburst Galaxies
Authors: Peck A. B. , Tarchi A. , Henkel C. , Nagar N. M. , Braatz J. , Moscadelli L.
Published: March 2016

We report new detections of three H2O megamasers and one kilomaser using the Effelsberg 100-m telescope. Isotropic luminosities are ~50, 300, 1, and 230 L⊙ for Mrk 1066, Mrk 34, NGC 3556, and Arp 299, respectively. Mrk 34 contains the most distant H2O megamaser ever detected in a Seyfert. Our targets in this survey were chosen to fit one of the following criteria: 1) to have a high probability of interaction between the radio jet and the ISM within the central few parsecs of the radio galaxy, yielding masers which arise in local molecular clouds; or 2) to have very bright IRAS sources in which massive star forming regions might yield powerful masers. The ‘jet maser’ sources can provide detailed information about the conditions in the ISM in the central 1-10 pc of AGN. The extra-galactic ‘star formation masers’ can be used to pinpoint and characterize locations of high mass star formation in nearby galaxies. In addition, these sources will help to provide a better understanding of the chemical properties of molecular clouds in extra-galactic systems.
Young Star Clusters: Metallicity Tracers in External Galaxies
Authors: Anders Peter , Alvensleben Uta Fritze – v. , de Grijs Richard
Published: March 2016

Star cluster formation is a major mode of star formation in the extreme conditions of interacting galaxies and violent star bursts. These newly-formed clusters are built from recycled gas, pre-enriched to various levels within the interacting galaxies. Hence, star clusters of different ages represent a fossil record of the chemical enrichment history of their host galaxy, as well as of the host galaxy’s violent star formation history. We present a new set of evolutionary synthesis models of our GALEV code, specifically developed to include the gaseous emission of presently forming star clusters, and a new tool to analyze multi-color observations with our models. First results for newly-born clusters in the dwarf star-burst galaxy NGC 1569 are presented.
The Nuclear Starburst in NGC 4945
Authors: Wang M. , Henkel C. , Chin Y.-N. , Whiteoak J. B. , Hunt Cunningham M. , Mauersberger R.
Published: March 2016

NGC 4945 is with D ~3-4 Mpc one of the nearest starburst galaxies known and a goldmine for molecular cloud research. A multi-line mm-wave study has been carried out towards its nuclear region with the Swedish-ESO Sub-millimetre Telescope (SEST). The study covers the frequency range from 82 GHz to 354 GHz and includes 80 transitions of 19 molecules, including rare isotope-bearing species. Applying a Large Velocity Gradient (LVG) code to the data, H2 densities and column densities of 22 molecular species are calculated. Many of these species indicate the presence of a prominent high density interstellar gas component characterized by nH2 ~105cm-3. Abundances of molecular species are calculated and compared with abundances observed toward the starburst galaxies NGC 253 and M 82 and galactic sources. Apparent is an ‘overabundance’ of HNC and CN in the nuclear environment of NGC 4945. NGC 4945 is the second known starburst galaxy with an HNC/HCN abundance ratio ≥1. Carbon, nitrogen, oxygen and sulfur isotope ratios are also determined. The data indicate that high 18O/17O, low 16O/18O and 14N/15N and perhaps also low 32S/34S ratios (6.4±0.3, 195±45, 105±25 and 13.5±2.5, respectively) are characteristic properties of a starburst environment in an advanced evolutionary stage.
Extragalactic Ammonia
Authors: Henkel C. , Menten K.M. , Braatz J. , Mauersberger R. , Weiß A. , Lebrón M. , Tarchi A. , Peck A. B. , Carilli C. L. , Lubowich D. A.
Published: March 2016

Multi-line data of ammonia (NH3) are presented for Maffei 2, IC 342, and the starburst galaxies NGC 253 and M 82. While in M 82 the NH3 emitting gas is cool, presumably arising from well shielded dense cores deeply embedded in an environment dominated by Photon Dominated Regions, the other galaxies show ‘warm’ and ‘hot’ components that may be heated by shocks, ion-slip or cosmic rays. Interferometric observations show the detailed large scale distribution of NH3 in galaxies for the first time. The first multi-line studies of ammonia at significant redshifts (z = 0.65 and 0.89) are also reported and rotational temperatures, measures of the kinetic temperature of the emitting gas, are derived for all sources.
Comparative Planetary Atmospheres of the Galilean Satellites
Authors: Strobel Darrell F.
Published: March 2016

We know that each of the Galilean satellites of Jupiter has a tenuous atmosphere by terrestrial standards. Io’s SO2 equatorial atmosphere and, perhaps, Callisto’s atmosphere inferred from its large ionospheric densities are measured in nanobars, whereas the atmospheres of Europa and Ganymede produced by ion sputtering of the water ice surfaces only reach picobar pressures and are comprised mostly of O2. Io’s polar atmosphere is probably an order of magnitude less dense than its equatorial atmosphere. Europa and Ganymede have O2 atmospheres with column densities in the range of (1-10)×1014cm−2. These atmospheres, on the basis of their inferred production and loss rates, are estimated to have short residence times of ~2-3 days.
Large Changes in Pluto’s Atmosphere Revealed by Stellar Occultations
Authors: Sicardy Bruno , Widemann Thomas , Lellouch Emmanuel , Roques Françoise , Gendron Eric , Veillet Christian , Cuillandre Jean-Charles , Colas François , Beisker Wolfgang , Kretlow Mike , Hainaut Olivier R. , Lidman Chris
Published: March 2016

Pluto’s tenuous nitrogen atmosphere was detected by stellar occultations in 1985 and 1988. This atmosphere is poorly known, however, due to the rarity of these events. We report here the first Pluto occultations observed since 1988, on 20 July and 21 August 2002. Our analysis reveals drastic changes undergone by the atmosphere since 1988, namely a two-fold pressure increase, the probable effect of seasonal changes on Pluto over this fourteen year interval.
Planetary Exploration and Archaeology: Heritage Conservation
Authors: Campbell John B.
Published: March 2016

Planetary exploration is resulting in the creation of new archaeological sites, material and debris on planets and their moons, and in various orbits round the Earth, Mars, the Sun etc. The main off-Earth bodies with sites so far are the Moon and Mars. Although thousands of archaeological sites on Earth are protected for their heritage value, no sites off-Earth are properly protected as yet. Sites off-Earth need to be ranked for their comparative heritage significance and protocols developed for the conservation and protection of the more significant sites and artifacts, before specimens are collected and returned to Earth in an uncontrolled (from heritage points of view) manner. A new United Nations Space Heritage Treaty is needed, or at least appropriate IAU and WAC (World Archaeological Congress) protocols agreed by the various parties concerned. The UN Outer Space Treaty 1967 is very out of date and a product of the Cold War.
The 23 November 2003 Total Solar Eclipse in Antarctica
Authors: Pasachoff Jay M.
Published: March 2016

Totality at the eclipse of 23 November 2003 will cross land only on Antarctica. Details of the path and contact information for safe observation are provided.
Results from the South Pole Infra-Red EXplorer Telescope
Authors: Rathborne J. M. , Burton M. G.
Published: March 2016

The SPIREX telescope, located at the Amundsen-Scott South Pole Station, was a prototype system developed to exploit the excellent conditions for IR observing at the South Pole. Observations over two winter seasons achieved remarkably deep, high-resolution, wide-field images in the 3-5 μm wavelength regime. Several star forming complexes were observed, including NGC 6334, Chamaeleon I, η Chamaeleontis, the Carina Nebula, 30 Doradus, RCW 57, RCW 38, as well as the Galactic Center. Images were obtained of lines at 2.42/μm H2, 3.29/μm PAH and 4.05/μm Br α, as well as 3.5/μm L-band and 4.7 μm M-band continuum emission. These data, combined with near-IR, mid-IR, and radio continuum maps, reveal the environments of these star forming sites, as well as any protostars lying within them. The SPIREX project, its observing and reduction methods, and some sample data are summarized here.
High Angular Resolution Mid-IR Astronomy at Concordia
Authors: Ferrari-Toniolo Marco
Published: March 2016

If we concentrate our attention on the study and the evolution of star forming processes rather than on the large scale structure, from the recent use of Large Telescopes in this context there are many examples of great interest. These include the study of the early phases of aggregation of matter (stellar and planet formation), and the late phases of disaggregation during stellar evolution. In Fig 1, a spectacular example is shown of a high resolution image of an edge-on circumstellar disk of a young star (HR4796A), with respect to previous less resolved information (C.Telesco et al, Proc SPIE 4834, 101, 2002). A recent hypothesis of a Large Infrared Telescope called GTA (Grande Telescopio Antartico) has been proposed to the PNRA (Italian Plan for Antarctic Researches). This will require the following characteristics: high angular resolution in the mid-IR domain (large aperture); very high sensitivity (mainly due to the cold, dry conditions of the site); extreme simplicity in design and operational modes. The telescope will be a survey instrument and will be used almost without human intervention. The project examines the construction of a third tower at Dome C with the telescope configured to work in quasi-drift-scan without moving the enclosure and with a limited tracking time. In Fig 1, a sketch of the tower hosting the telescope is shown (M.F-T. et al, Proc SPIE 4836, 165, 2002). A study will be developed to determine the optimum configurations for observing in different bands, from the optical to the sub-mm range, with a refurbishment of the telescope and instrumentation during the summer break.
An Introduction to the Nomenclature Problem
Authors: Mason Brian D. , Hartkopf William I.
Published: March 2016

The new observing and reduction techniques available to astronomers have led to remarkable changes in the field of double and multiple stars. New classes of companions, such as brown dwarfs and exoplanets, have been discovered. Binaries which previously constituted distinct classes are now observable by multiple techniques. With many long-baseline optical interferometers operational or planned, with improvements in other techniques, and with astrometric space-based missions in various states of planning and funding, the situation is likely to become more complicated. The result is greater understanding for the scientist, but greater challenges for the cataloger!

The “problem” is that purveyors of different techniques use different nomenclature, both in terms of root designation and component identifier. It is this latter inconsistency which causes the most confusion and is the topic of this Special Session.

This talk will illustrate some of the many designation ambiguities and summarize efforts made during the past few years to address this problem.
Nomenclature Scheme in use by the WGESP and a Current List of Extrasolar Planets
Authors: Tarter Jill C.
Published: March 2016

At the IAU General Assembly in 2000, the Working Group on Extrasolar Planets (WGESP) was established as a working group of Division III. Its terms of reference include acting as a focal point for international research on extra solar planets and organizing IAU activities in the field, such as, organizing comparative reviews of techniques used to detect extra-solar planets and establishing criteria for detections of varying degrees of certainty, as well as maintaining lists of objects satisfying these criteria. The committee is chaired by Alan Boss, and the current members are; Paul Butler, William Hubbard, Philip Ianna, Martin Kiirster, Jack Lissauer, Michel Mayor, Karen Meech, Francois Mignard, Alan Penny, Andreas Quirrenbach, Jill Tarter, and Alfred Vidal-Madjar.
A Short Overview of Astronomical Education Carried Out by the International Astronomical Union (IAU)
Authors: Isobe Syuzo
Published: March 2016

The IAU is a union of professional astronomers who produce new astronomical results and who make the frontiers of astronomy expand. However, the IAU cannot stand by itself but needs the support of governments as well as the people. This is one reason why the IAU set up Commission 46 – originally called “Teaching of Astronomy” and renamed “Astronomy Education and Development” with much wider mandate in 2000 – to cover astronomy education from the level of beginners to that of post-doctoral students.
Textbooks for K-12 Astronomy
Authors: Pasachoff Jay M.
Published: March 2016

I report on American textbooks for kindergarten through highschool grades. Middle school, up through approximate age 15, is the last time American students are required to take science, and I provide statistics on the narrowing of the funnel containing those taking physics. I describe some recent curriculum and standards projects, and I discuss the recent “less is more” trend. I conclude with comments on whether textbooks are necessary and useful and discuss possible content and style of an ideal textbook.
Shielding of the Geomagnetic Field Alters Actin Assembly and Inhibits Cell Motility in Human Neuroblastoma Cells
Authors: Mo Wei-Chuan , Zhang Zi-Jian , Wang Dong-Liang , Liu Ying , Bartlett Perry F. , He Rong-Qiao
Published: March 2016

Accumulating evidence has shown that absence of the geomagnetic field (GMF), the so-called hypomagnetic field (HMF) environment, alters the biological functions in seemingly non-magnetosensitive cells and organisms, which indicates that the GMF could be sensed by non-iron-rich and non-photo-sensing cells. The underlying mechanisms of the HMF effects on those cells are closely related to their GMF sensation but remain poorly understood so far. Previously, we found that the HMF represses expressions of genes associated with cell migration and cytoskeleton assembly in human neuroblastoma cells (SH-SY5Y cell line). Here, we measured the HMF-induced changes on cell morphology, adhesion, motility and actin cytoskeleton in SH-SY5Y cells. The HMF inhibited cell adhesion and migration accompanied with a reduction in cellular F-actin amount. Moreover, following exposure to the HMF, the number of cell processes was reduced and cells were smaller in size and more round in shape. Furthermore, disordered kinetics of actin assemblyin vitrowere observed during exposure to the HMF, as evidenced by the presence of granule and meshed products. These results indicate that elimination of the GMF affects assembly of the motility-related actin cytoskeleton, and suggest that F-actin is a target of HMF exposure and probably a mediator of GMF sensation.
Noise propagation with interlinked feed-forward pathways
Authors: Chepyala Surendhar Reddy , Chen Yi-Chen , Yan Ching-Cher Sanders , Lu Chun-Yi David , Wu Yi-Chun , Hsu Chao-Ping
Published: March 2016

Functionally similar pathways are often seen in biological systems, forming feed-forward controls. The robustness in network motifs such as feed-forward loops (FFLs) has been reported previously. In this work, we studied noise propagation in a development network that has multiple interlinked FFLs. A FFL has the potential of asymmetric noise-filtering (i.e., it works at either the “ON” or the “OFF” state in the target gene). With multiple, interlinked FFLs, we show that the propagated noises are largely filtered regardless of the states in the input genes. The noise-filtering property of an interlinked FFL can be largely derived from that of the individual FFLs and with interlinked FFLs, it is possible to filter noises in both “ON” and “OFF” states in the output. We demonstrated the noise filtering effect in the developmental regulatory network of Caenorhabditis elegans that controls the timing of distal tip cell (DTC) migration. The roles of positive feedback loops involving blmp-1 and the degradation regulation of DRE-1 also studied. Our analyses allow for better inference from network structures to noise-filtering properties and provide insights into the mechanisms behind the precise DTC migration controls in space and time.
Enzymatic properties, evidence for in vivo expression, and intracellular localization of shewasin D, the pepsin homolog from Shewanella denitrificans
Authors: Leal Ana Rita , Cruz Rui , Bur Daniel , Huesgen Pitter F. , Faro Rosário , Manadas Bruno , Wlodawer Alexander , Faro Carlos , Simões Isaura
Published: March 2016

The widespread presence of pepsin-like enzymes in eukaryotes together with their relevance in the control of multiple biological processes is reflected in the large number of studies published so far for this family of enzymes. By contrast, pepsin homologs from bacteria have only recently started to be characterized. The work with recombinant shewasin A from Shewanella amazonensis provided the first documentation of this activity in prokaryotes. Here we extend our studies to shewasin D, the pepsin homolog from Shewanella denitrificans, to gain further insight into this group of bacterial peptidases that likely represent ancestral versions of modern eukaryotic pepsin-like enzymes. We demonstrate that the enzymatic properties of recombinant shewasin D are strongly reminiscent of eukaryotic pepsin homologues. We determined the specificity preferences of both shewasin D and shewasin A using proteome-derived peptide libraries and observed remarkable similarities between both shewasins and eukaryotic pepsins, in particular with BACE-1, thereby confirming their phylogenetic proximity. Moreover, we provide first evidence of expression of active shewasin D in S. denitrificans cells, confirming its activity at acidic pH and inhibition by pepstatin. Finally, our results revealed an unprecedented localization for a family A1 member by demonstrating that native shewasin D accumulates preferentially in the cytoplasm.
Field-driven domain wall motion under a bias current in the creep and flow regimes in Pt/[CoSiB/Pt]N nanowires
Authors: Choi Y. H. , Yoshimura Y. , Kim K.-J. , Lee K. , Kim T. W. , Ono T. , You C.-Y. , Jung M. H.
Published: March 2016

The dynamics of magnetic domain wall (DW) in perpendicular magnetic anisotropy Pt/[CoSiB/Pt]N nanowires was studied by measuring the DW velocity under a magnetic field (H) and an electric current (J) in two extreme regimes of DW creep and flow. Two important findings are addressed. One is that the field-driven DW velocity increases with increasing N in the flow regime, whereas the trend is inverted in the creep regime. The other is that the sign of spin current-induced effective field is gradually reversed with increasing N in both DW creep and flow regimes. To reveal the underlying mechanism of new findings, we performed further experiment and micromagnetic simulation, from which we found that the observed phenomena can be explained by the combined effect of the DW anisotropy, Dzyaloshinskii-Moriya interaction, spin-Hall effect, and spin-transfer torques. Our results shed light on the mechanism of DW dynamics in novel amorphous PMA nanowires, so that this work may open a path to utilize the amorphous PMA in emerging DW-based spintronic devices.
YSZ thin films with minimized grain boundary resistivity
Authors: Mills Edmund M. , Kleine-Boymann Matthias , Janek Juergen , Yang Hao , Browning Nigel D. , Takamura Yayoi , Kim Sangtae
Published: March 2016

The grain boundary resistance of nano-columnar yttria-stabilized zirconia thin films is almost completely eliminated near the film–substrate interface through substrate induced magnesium doping.
Reinforced cyclam derivatives functionalized on the bridging unit
Authors: Sok Nicolas , Baglin Isabelle , Rousselin Yoann , Boschetti Frederic , Bernhard Claire , Goze Christine , Denat Franck
Published: March 2016

The introduction of one or two nitriles on the bridge of reinforced cyclams paves the way for the synthesis of new bifunctional chelating agents. X-ray structures of the chelators and of two copper complexes are reported.
Crystal growth, structure and optical properties of a new acentric crystal La2Al4.68B8O22 with a short UV absorption edge
Authors: Guo Shu , Liu Lijuan , Xia Mingjun , Wang Xiaoyang , Bai Lei , Xu Bo , Huang Qian , Chen Chuangtian
Published: March 2016

A new acentric borate La2Al4.68B8O22 crystal, grown using the top seeded solution growth method, shows a short absorption edge at 193 nm.
Exploring the thermodynamics and conformational aspects of nicotinic acid binding with bovine serum albumin: a detailed calorimetric, spectroscopic and molecular docking study
Authors: Banipal Tarlok Singh , Kaur Amandeep , Khan Imran Ahmd , Banipal Parampaul Kaur
Published: March 2016

An attempt to obtain a physicochemical and conformational outlook on the binding interaction of vitamin B3(NA) with a model transport protein BSA using calorimetry, light scattering, molecular docking, and spectroscopic techniques.
Resonance Raman spectroscopy as an in situ probe for monitoring catalytic events in a Ru–porphyrin mediated amination reaction
Authors: Zardi Paolo , Gallo Emma , Solan Gregory A. , Hudson Andrew J.
Published: March 2016

A method to monitor the mechanisms of homogeneously-catalysed reactions under conditions of refluxing solvents using resonance Raman spectroscopy.
Orthogonal strategy for the synthesis of dual-functionalised β3-peptide based hydrogels
Authors: Kulkarni Ketav , Motamed Sepideh , Habila Nathan , Perlmutter Patrick , Forsythe John S. , Aguilar Marie-Isabel , Del Borgo Mark P.
Published: March 2016

We describe a new class of hydrogelator based on helical β3-peptide foldamers carrying a bioactive payload. The β3-peptides self-assemble to form a nanofibrous mesh resulting in a stable hydrogel. Co-incubation with different β3-peptide monomers allowed tuning of cell adherence.
M8L12 cubic cages with all facial Δ or facial Λ configuration: effects of surface anions on the occupancy of the cage and anion exchange
Authors: Yang Jing , Chang Xiao-Yong , Sham Kiu-Chor , Yiu Shek-Man , Kwong Hoi-Lun , Che Chi-Ming
Published: March 2016

M8L12 cubic cages (M = MnII, ZnII or CdII), with all eight metal ions having all facial Δ or facial Λ configurations and having an encapsulated anion, were prepared by the self-assembly of m-xylene-bridged imidazolyl-imine ligands and MX2 (X = PF6−, SbF6−, TfO−) salts.
Investigation of sodium insertion–extraction in olivine NaxFePO4 (0 ≤ x ≤ 1) using first-principles calculations
Authors: Saracibar A. , Carrasco J. , Saurel D. , Galceran M. , Acebedo B. , Anne H. , Lepoitevin M. , Rojo T. , Casas Cabanas M.
Published: March 2016

A molecular level investigation of sodium insertion–extraction in olivine NaxFePO4 as a promising cathode material for sodium-ion batteries.
Spontaneous aggregation of lithium ion coordination polymers in fluorinated electrolytes for high-voltage batteries
Authors: Malliakas Christos D. , Leung Kevin , Pupek Krzysztof Z. , Shkrob Ilya A. , Abraham Daniel P.
Published: March 2016

We report delayed spontaneous formation of solvate coordination polymers of lithium ions and their aggregation and phase separation in fluorinated electrolytes.
A neutron scattering and modelling study of aqueous solutions of tetramethylammonium and tetrapropylammonium bromide
Authors: Nilsson Emelie J. , Alfredsson Viveka , Bowron Daniel T. , Edler Karen J.
Published: March 2016

Tetrapropylammonium ions cluster and have less structured water arrangements whereas tetramethylammonium ions occur as single molecules with tetrahedral water arrangements.
Self-assembled nanoparticle patterns on carbon nanowall surfaces
Authors: Suetin N. V. , Evlashin S. A. , Egorov A. V. , Mironovich K. V. , Dagesyan S. A. , Yashina L. V. , Goodilin E. A. , Krivchenko V. A.
Published: March 2016

We observed self-assembled quasiregular structures of diverse nanoparticles on a freestanding multilayer graphene-like material.
A 3-D net based on weak metallophilic (Cu⋯Cu) interactions
Authors: Zhou Jian , Tan Xiaofeng , Hu Feilong , Zou Hua-Hong , Almeida Paz Filipe A. , Fu Lianshe , Zhao Rongqing
Published: March 2016

The interconnection of 1-D [Cu(IN)] chains via weak metallophilic (Cu⋯Cu) interactions gives a 3-D network with photocatalytic properties.
From microgalaxies to micro-oceans to Warhol's cellular images: the art in science of MicroTAS 2015
Authors: Reyes Darwin R.
Published: March 2016

Matteo Cornaglia (center) from École Polytechnique Fédérale de Lausanne (EPFL) receives the MicroTAS 2015 Art in Science award presented by Darwin Reyes (left) from NIST and Sarah Ruthven (right) from Lab on a Chip/The Royal Society of Chemistry.
Liquid phase microextraction based on the solidification of a floating ionic liquid combined with high-performance liquid chromatography for the preconcentration of phthalate esters in environmental waters and in bottled beverages
Authors: Hu Lu , Shan Wanyu , Zhang Ying , Li Songqing , Gao Haixiang , Lu Runhua , Zhang Sanbing , Zhou Wenfeng
Published: March 2016

Liquid-phase microextraction based on the solidification of floating ionic liquids.
Structural and electronic properties of the PbCrO4 chrome yellow pigment and of its light sensitive sulfate-substituted compounds
Authors: Amat Anna , Miliani Costanza , Fantacci Simona
Published: March 2016

Chrome Yellows (CY) are a family of synthetic pigments of formula (PbCr(1−x)SxO4) used by van Gogh. We investigate structure/property relations in CY by first-principles methods, providing insight into their possible degradation mechanisms.
Self-assembly structural transition of protic ionic liquids and P123 for inducing hierarchical porous materials
Authors: Zhang Mingyu , Zhang Yiwei , Sheng Xiaoli , Zhou Yuming , Zhao Shuo , Fu Xiaoqin , Zhang Hongxing
Published: March 2016

Hierarchical micro–mesoporous silica–zirconium has been obtained by a simple procedure by adjusting the interaction between protic ionic liquids (NTA) and Pluronic 123 surfactant in acidic media through changing the content of NTA and the pH of the solutions.
A novel magnetic calcium silicate/graphene oxide composite material for selective adsorption of acridine orange from aqueous solutions
Authors: Wang Huan , Chen Youning , Wei Yinmao
Published: March 2016

The adsorption behavior of acridine orange on magnetic calcium silicate/graphene oxide composite material.
High-affinity Anticalins with aggregation-blocking activity directed against the Alzheimer β-amyloid peptide
Authors: Rauth Sabine , Hinz Dominik , Börger Michael , Uhrig Markus , Mayhaus Manuel , Riemenschneider Matthias , Skerra Arne
Published: March 2016

Amyloid beta (Aβ) peptides, in particular Aβ42 and Aβ40, exert neurotoxic effects and their overproduction leads to amyloid deposits in the brain, thus constituting an important biomolecular target for treatments of Alzheimer's disease (AD). We describe the engineering of cognate Anticalins as a novel type of neutralizing protein reagent based on the human lipocalin scaffold. Phage display selection from a genetic random library comprising variants of the human lipocalin 2 (Lcn2) with mutations targeted at 20 exposed amino acid positions in the four loops that form the natural binding site was performed using both recombinant and synthetic target peptides and resulted in three different Anticalins. Biochemical characterization of the purified proteins produced by periplasmic secretion in Escherichia coli revealed high folding stability in a monomeric state, with Tm values ranging from 53.4°C to 74.5°C, as well as high affinities for Aβ40, between 95 pM and 563 pM, as measured by real-time surface plasmon resonance analysis. The central linear VFFAED epitope within the Aβ sequence was mapped using a synthetic peptide array on membranes and was shared by all three Anticalins, despite up to 13 mutual amino acid differences in their binding sites. All Anticalins had the ability–with varying extent–to inhibit Aβ aggregation in vitro according to the thioflavin-T fluorescence assay and, furthermore, they abolished Aβ42-mediated toxicity in neuronal cell culture. Thus, these Anticalins provide not only useful protein reagents to study the molecular pathology of AD but they also show potential as alternative drug candidates compared with antibodies.
Integrating Written Text and Graphic Cues Into Peer-Mediated Interventions: Effects on Reciprocal Social Communication Skills
Authors: Miller Todd M. , Thiemann-Bourque Kathy
Published: March 2016

A growing body of evidence has supported the use of peer-mediated interventions to increase the social-communication skills of students with a variety of developmental disabilities, including autism spectrum disorders (ASD). Despite these promising results, however, many practitioners may struggle to effectively implement peer-mediated interventions across the diverse presentation and skill profiles of students with ASD, specifically in accommodating the unique language and communication needs of their students. This article presents an example of integrating written-graphic and text cues into a peer-mediated intervention for three elementary-age students with ASD. Emphasis is placed on describing the teaching procedures used to encourage students with ASD and peers to participate in shared games and activities together, using written-graphic and text cues to support appropriate social communication. Additionally, strategies for selecting and including typically-developing peers to participate in social skills programming are reviewed. Data collected throughout the peer-mediated intervention demonstrates the positive effect of systematic social skills instruction for both students with disabilities and their peers.
Influence of biological subject, shielding cage, and resonance frequency on radio wave propagation in a birdcage coil
Authors: Seo J.‐H. , Ryu Y. , Han S.‐D. , Song H. , Kim H.‐K. , Kim K.‐N.
Published: March 2016

Radio wave propagation of three types of birdcage transmit/receive radio‐frequency (RF) coils (lowpass filter, highpass filter, and bandpass filter configurations) was analysed for mouse body magnetic resonance imaging at main magnetic fields of 1.5, 3.0, 4.7, 7.0, 9.4, and 11.7 T (Larmor frequencies of 63.87, 127.74, 200, 300, 400, and 500 MHz) in terms of magnetic (|B1|) field sensitivity and homogeneity. The observed radio wave propagation in the central axial |B1| field, as influenced by the biological subject, was calculated numerically in the finite‐difference time‐domain method and compared with assessment criteria using the mean value and standard deviation. The results for different Larmor frequencies RF shielding cage configurations, and biological subject loading versus unloading were compared and are discussed in detail.
Two‐step reset method for energy‐efficient SAR ADC switching schemes
Authors: Osipov D. , Paul St.
Published: March 2016

The impact of the reset energy on the overall energy efficiency of an successive‐approximation register (SAR) ADC is examined for some recently reported switching schemes. The reset energy can several times exceed the switching energy drawn from the reference during conversion. The simple method based on the optimal capacitor charging is proposed. By utilising of two‐step switching during the reset phase, the total energy consumption of the DAC's capacitive matrix can be decreased by ∼20%.
Effects of monohydric alcohols and polyols on the thermal stability of a protein
Authors: Murakami Shota , Kinoshita Masahiro
Published: March 2016

The thermal stability of a protein is lowered by the addition of a monohydric alcohol, and this effect becomes larger as the size of hydrophobic group in an alcohol molecule increases. By contrast, it is enhanced by the addition of a polyol possessing two or more hydroxyl groups per molecule, and this effect becomes larger as the number of hydroxyl groups increases. Here, we show that all of these experimental observations can be reproduced even in a quantitative sense by rigid-body models focused on the entropic effect originating from the translational displacement of solvent molecules. The solvent is either pure water or water-cosolvent solution. Three monohydric alcohols and five polyols are considered as cosolvents. In the rigid-body models, a protein is a fused hard spheres accounting for the polyatomic structure in the atomic detail, and the solvent is formed by hard spheres or a binary mixture of hard spheres with different diameters. The effective diameter of cosolvent molecules and the packing fractions of water and cosolvent, which are crucially important parameters, are carefully estimated using the experimental data of properties such as the density of solid crystal of cosolvent, parameters in the pertinent cosolvent-cosolvent interaction potential, and density of water-cosolvent solution. We employ the morphometric approach combined with the integral equation theory, which is best suited to the physical interpretation of the calculation result. It is argued that the degree of solvent crowding in the bulk is the key factor. When it is made more serious by the cosolvent addition, the solvent-entropy gain upon protein folding is magnified, leading to the enhanced thermal stability. When it is made less serious, the opposite is true. The mechanism of the effects of monohydric alcohols and polyols is physically the same as that of sugars. However, when the rigid-body models are employed for the effect of urea, its addition is predicted to enhance the thermal stability, which conflicts with the experimental fact. We then propose, as two essential factors, not only the solvent-entropy gain but also the loss of protein-solvent interaction energy upon protein folding. The competition of changes in these two factors induced by the cosolvent addition determines the thermal-stability change.
Development of a compact generator for gigawatt, nanosecond high-voltage pulses
Authors: Zhou Lin , Jiang Zhanxing , Liang Chuan , Li Mingjia , Wang Wenchuan , Li Zhenghong
Published: March 2016

A compact generator producing 2.2-ns 1.5 GW high-voltage pulses was developed. The generator employed a 27.6 Ω, 0.9 ns pulse-forming-line (PFL), which was charged by an iron core transformer with a turn ratio of 2:33.5 and a coefficient of 0.94. A 1.2 μF, 20 kV capacitor and a hydrogen thyratron were used in the primary circuit. When the thyratron closed at 14.5 kV, 3.4% of the energy stored in the capacitor was delivered to the PFL in 850 ns, producing a peak voltage of up to ∼500 kV. In addition, the principle of triple resonance transformation was employed by adding a 50 pF tuning capacitor and a 1.15 mH inductor between the transformer and the PFL, which led to a significant reduction of the duration and peak value of the transformer voltage without reducing that in the PFL. Meanwhile, an adjustable self-break oil switch was applied. By using transmission lines with impedance overmatched to that of the PFL, the generator delivered a 512 kV pulse across an electron beam diode, generating radiation with a dose of 20 mR/pulse at 20 cm ahead of the diode. The generator provides an excellent ultra-short radiation pulse source for the studies on radiation physics.
High-pressure differential scanning microcalorimeter
Authors: Senin A. A. , Dzhavadov L. N. , Potekhin S. A.
Published: March 2016

A differential scanning microcalorimeter for studying thermotropic conformational transitions of biopolymers at high pressure has been designed. The calorimeter allows taking measurements of partial heat capacity of biopolymer solutions vs. temperature at pressures up to 3000 atm. The principles of operation of the device, methods of its calibration, as well as possible applications are discussed.
Direct observation of binding stress-induced crystalline orientation change in piezoelectric plate sensors
Authors: Wu Wei , Shih Wei-Heng , Shih Wan Y.
Published: March 2016

We have examined the mechanism of the detection resonance frequency shift, Δf/f, of a 1370 μm long and 537 μm wide [Pb(Mg1/3Nb2/3)O3]0.65[PbTiO3]0.35 (PMN-PT) piezoelectric plate sensor (PEPS) made of a 8-μm thick PMN-PT freestanding film. The Δf/f of the PEPS was monitored in a three-step binding model detections of (1) binding of maleimide-activated biotin to the sulfhydryl on the PEPS surface followed by (2) binding of streptavidin to the bound biotin and (3) subsequent binding of biotinylated probe deoxyribonucleic acid to the bound streptavidin. We used a PMN-PT surrogate made of the same 8-μm thick PMN-PT freestanding film that the PEPS was made of but was about 1 cm in length and width to carry out crystalline orientation study using X-ray diffraction (XRD) scan around the (002)/(200) peaks after each of the binding steps. The result of the XRD studies indicated that each binding step caused the crystalline orientation of the PMN-PT thin layer to switch from the vertical (002) orientation to the horizontal (200) orientation, and most of the PEPS detection Δf/f was due to the change in the lateral Young's modulus of the PMN-PT thin layer as a result of the crystalline orientation change.
Neoclassical parallel flow calculation in the presence of external parallel momentum sources in Heliotron J
Authors: Nishioka K. , Nakamura Y. , Nishimura S. , Lee H. Y. , Kobayashi S. , Mizuuchi T. , Nagasaki K. , Okada H. , Minami T. , Kado S. , Yamamoto S. , Ohshima S. , Konoshima S. , Sano F.
Published: March 2016

A moment approach to calculate neoclassical transport in non-axisymmetric torus plasmas composed of multiple ion species is extended to include the external parallel momentum sources due to unbalanced tangential neutral beam injections (NBIs). The momentum sources that are included in the parallel momentum balance are calculated from the collision operators of background particles with fast ions. This method is applied for the clarification of the physical mechanism of the neoclassical parallel ion flows and the multi-ion species effect on them in Heliotron J NBI plasmas. It is found that parallel ion flow can be determined by the balance between the parallel viscosity and the external momentum source in the region where the external source is much larger than the thermodynamic force driven source in the collisional plasmas. This is because the friction between C6+ and D+ prevents a large difference between C6+ and D+ flow velocities in such plasmas. The C6+ flow velocities, which are measured by the charge exchange recombination spectroscopy system, are numerically evaluated with this method. It is shown that the experimentally measured C6+ impurity flow velocities do not contradict clearly with the neoclassical estimations, and the dependence of parallel flow velocities on the magnetic field ripples is consistent in both results.
Quasi-monoenergetic proton beam from a proton-layer embedded metal foil irradiated by an intense laser pulse
Authors: Kim Kyung Nam , Lee Kitae , Kumar Manoj , Kim Ha-Na , Park Seong Hee , Jeong Young Uk , Vinokurov Nikolay , Kim Yong Gi
Published: March 2016

A target structure, ion-layer embedded foil (ILEF) is proposed for producing a quasi-monoenergetic proton beam by utilizing a bulk electrostatic field, which is generated by irradiating the target with an ultra-intense laser pulse, inside the plasma. Compared with the case of a single metal foil in which the proton layer is initially present on the surface, in the ILEF target, the proton layer is initially located inside a metal foil. A two-dimensional particle-in-cell (PIC) simulation shows that the target generates a proton beam with a narrow energy spread. With a laser intensity of 2 × 1019 W/cm2, a 22-MeV proton beam with an energy spread of 8% at the full-width-half-maximum (FWHM) is obtained when the proton layer is located at 0.4 μm inside the rear surface of a 2.4 μm-thick copper foil. When the proton layer moves toward the front side, a proton beam with a flat-top energy distribution ranging from 15 MeV to 35 MeV is obtained. Further, with a higher laser intensity of 1021 W/cm2, a proton beam with the maximum energy of 345 MeV and FWHM energy spread of 7.2% is obtained. The analysis of the PIC simulation with an aid of a fluid analysis shows that the spectrum is affected by the initial position of the proton layer, its initial spread during the formation of the sheath field, and the space charge effect.
Cleaning graphene: A first quantum/classical molecular dynamics approach
Authors: Delfour L. , Davydova A. , Despiau-Pujo E. , Cunge G. , Graves D. B. , Magaud L.
Published: March 2016

Graphene outstanding properties created a huge interest in the condensed matter community and unprecedented fundings at the international scale in the hope of application developments. Recently, there have been several reports of incomplete removal of the polymer resists used to transfer as-grown graphene from one substrate to another, resulting in altered graphene transport properties. Finding a large-scale solution to clean graphene from adsorbed residues is highly desirable and one promising possibility would be to use hydrogen plasmas. In this spirit, we couple here quantum and classical molecular dynamics simulations to explore the kinetic energy ranges required by atomic hydrogen to selectively etch a simple residue—a CH3 group—without irreversibly damaging the graphene. For incident energies in the 2–15 eV range, the CH3 radical can be etched by forming a volatile CH4 compound which leaves the surface, either in the CH4 form or breaking into CH3 + H fragments, without further defect formation. At this energy, adsorption of H atoms on graphene is possible and further annealing will be required to recover pristine graphene.
Kinetic Monte Carlo modeling of the efficiency roll-off in a multilayer white organic light-emitting device
Authors: Mesta M. , van Eersel H. , Coehoorn R. , Bobbert P. A.
Published: March 2016

Triplet-triplet annihilation (TTA) and triplet-polaron quenching (TPQ) in organic light-emitting devices (OLEDs) lead to a roll-off of the internal quantum efficiency (IQE) with increasing current density J. We employ a kinetic Monte Carlo modeling study to analyze the measured IQE and color balance as a function of J in a multilayer hybrid white OLED that combines fluorescent blue with phosphorescent green and red emission. We investigate two models for TTA and TPQ involving the phosphorescent green and red emitters: short-range nearest-neighbor quenching and long-range Förster-type quenching. Short-range quenching predicts roll-off to occur at much higher J than measured. Taking long-range quenching with Förster radii for TTA and TPQ equal to twice the Förster radii for exciton transfer leads to a fair description of the measured IQE-J curve, with the major contribution to the roll-off coming from TPQ. The measured decrease of the ratio of phosphorescent to fluorescent component of the emitted light with increasing J is correctly predicted. A proper description of the J-dependence of the ratio of red and green phosphorescent emission needs further model refinements.
Phase structure–electrical property relationships in Pb(Ni1/3Nb2/3)O3–Pb(Zr,Ti)O3-based ceramics
Authors: Nie Rui , Zhang Qian , Yue Yang , Liu Hong , Chen Yanbin , Chen Qiang , Zhu Jianguo , Yu Ping , Xiao Dingquan
Published: March 2016

Generally, the phase structure change of Pb(B′ B″)O3–PZT solid solutions near a morphotropic phase boundary (MPB) can be originated from composition variations. Here our results show that the excess PbO and the sintering temperature can also result in the ferroelectric phase structure change in the Pb(Ni1/3Nb2/3)O3–Pb(Zr,Ti)O3 (PNN–PZT)-based ceramics near the MPB. The dielectric, piezoelectric, and ferroelectric properties are dependent on the tetragonal phase content (TP) which is closely associated with the excess PbO and the sintering temperature. The temperature dependence of the polarization (P)–electric field (E) hysteresis loops reveals that the tetragonal phase in the PNN–PZT-based ceramics has a lower activation energy (Ea) for domain wall movement than that of the rhombohedral phase, thus resulting in easier polarization rotation. This is responsible for the phase structure–electrical property relationships in the PNN–PZT-based ceramics, exhibiting the dependence of the tetragonal phase content (TP) on the electrical properties.