bluuebunny/crossref_metadata_2025 huggingface dataset:
Brine film thicknesses on mica surfaces under geologic CO2 sequestration conditions and controlled capillary pressures
Authors: Kim Tae Wook , Tokunaga Tetsu K. , Bargar John R. , Latimer Matthew J. , Webb Samuel M.
Published: July 2013

Brine films remaining on mineral surfaces in deep reservoirs during CO2 sequestration are expected to influence multiphase flow, diffusion, and reactions, but little is known about their behavior. Using synchrotron X‐ray fluorescence (XRF), we measured thicknesses of KCsI2 brine films on two difference roughness mica surfaces under conditions representative of geological CO2 sequestration (7.8 MPa and 40°C) to understand the influences of mineral surface roughness and capillary potential. Brine thicknesses measured on the Mica 1 (smooth) and Mica 2 (rough) mica surfaces ranged from 23 to 8 nm and 491 to 412 nm, respectively, over the small range of tested capillary potentials (0.18–3.7 kPa). Within these potentials, brine film thicknesses on mica were governed by surface roughness and only weakly influenced by capillary potentials. In comparing drainage and rewetting isotherms, some film thickness hysteresis was observed, possibly indicative of changes in mica wettability.
Energetic Compounds Based on 4‐Amino‐1, 2, 4‐triazole (ATZ) and Picrate (PA): [Zn(H2O)6](PA)2·3H2O and [Zn(ATZ)3](PA)2·2.5H2O]n
Authors: Wu Bi‐Dong , Zhang Tong‐Lai , Li Yu‐Lu , Tong Wen‐Chao , Zhou Zun‐Ning , Zhang Jian‐Guo , Yang Li
Published: July 2013

Two energetic compounds, [Zn(H2O)6](PA)2·3H2O (1) and [Zn(ATZ)3](PA)2·2.5H2O]n (2), were synthesized based on 4‐amino‐1,2,4‐triazole (ATZ) and picrate (PA), and characterized by elemental analysis and Fourier transform infrared (FT‐IR) spectroscopy. The crystallographic data showed that the crystals of 1 and 2 belong to the monoclinic space group P21/n and the triclinic space group P$\bar{1}$, respectively. Furthermore, the ZnII cations are six‐coordinated with six oxygen atoms from crystal water molecules for 1 and six nitrogen atoms from ATZ for 2, and exhibit distorted octahedral configurations. Thermal decomposition mechanisms were determined based on differential scanning calorimeter (DSC) curve corresponding to thermogravimetry‐derivative thermogravimetry (TG‐DTG) curves and kinetic parameters of the first exothermic process were studied by using Kissinger's and Ozawa's method. The energies of the impact sensitivities were 27.8 J for 2 and far greater than 29.4 J for 1. In addition, the experiment found the heats of combustion were –6.53 MJ·kg–1 for 1 and –11.33 MJ·kg–1 for 2 by oxygen bomb calorimeter. Therefore, compound 2 can improve the explosion performance and can maybe regarded as the less toxicity energy additive for the explosives and propellant formulations.
The near field refractor
Authors: Gutiérrez Cristian E. , Huang Qingbo
Published: July 2013

We present an abstract method in the setting of compact metric spaces which is applied to solve a number of problems in geometric optics. In particular, we solve the one source near field refraction problem. That is, we construct surfaces separating two homogeneous media with different refractive indices that refract radiation emanating from the origin into a target domain contained in an

n−1

dimensional hypersurface. The input and output energy are prescribed. This implies the existence of lenses focusing radiation in a prescribed manner.
The source of cognitive complaints predicts diagnostic conversion differentially among nondemented older adults
Authors: Gifford Katherine A. , Liu Dandan , Lu Zengqi , Tripodis Yorghos , Cantwell Nicole G. , Palmisano Joseph , Kowall Neil , Jefferson Angela L.
Published: July 2013

Objective

The objective of this study was to compare whether different sources of cognitive complaint (i.e., subjective and informant) predict diagnostic conversion in nondemented older adults.

Methods

Participants from the National Alzheimer's Coordinating Center had a baseline diagnosis of normal cognition (NC; n = 4414; mean age, 73 ± 8 years; 69% female) or mild cognitive impairment (MCI; n = 1843; mean age, 74 ± 8 years; 52% female). Multinomial logistic regression related baseline cognitive complaint (no complaint, self only, informant only, or both self and informant) to diagnostic outcome (reversion, stable, or conversion).

Results

At follow‐up, 14% of NC participants converted to MCI/dementia (3.5 ± 1.8 years), and 41% of MCI participants converted to dementia (3.0 ± 1.6 years). Among NC participants, self complaint only (odds ratio [OR], 2.1; 99% confidence interval (CI),1.5–2.9; P < .001), informant complaint only (OR, 2.2; 99% CI, 1.2–3.9; P < .001), and both self and informant complaint (OR, 4.2; 99% CI, 2.9–6.0; P < .001) were associated with diagnostic conversion compared with no complaint. Among participants with MCI—compared with no complaint, informant complaint only (OR, 2.2; 99% CI, 1.2–4.3, P = .002), and both self and informant complaint (OR, 2.9; 99% CI, 1.8–4.8; P < .001)—were associated with conversion.

Conclusions

Cognitive complaints are related to conversion among nondemented older adults. Complaint from both (i.e. mutual complaint) sources was most predictive of diagnostic outcome, followed by informant complaint, highlighting the need for obtaining informant corroboration to enhance prognosis and distinguish underlying pathological processes from normal cognitive aging. Self complaint was related inconsistently to diagnostic outcome.
Modelling spreading dynamics of nematic liquid crystals in three spatial dimensions
Authors: Lin T.-S. , Kondic L. , Thiele U. , Cummings L. J.
Published: July 2013

We study spreading dynamics of nematic liquid crystal droplets within the framework of the long-wave approximation. A fourth-order nonlinear parabolic partial differential equation governing the free surface evolution is derived. The influence of elastic distortion energy and of imposed anchoring variations at the substrate are explored through linear stability analysis and scaling arguments, which yield useful insight and predictions for the behaviour of spreading droplets. This behaviour is captured by fully nonlinear time-dependent simulations of three-dimensional droplets spreading in the presence of anchoring variations that model simple defects in the nematic orientation at the substrate.
Targeted proteomics reveals strain‐specific changes in the mouse insulin and central metabolic pathways after a sustained high‐fat diet
Authors: Sabidó Eduard , Wu Yibo , Bautista Lucia , Porstmann Thomas , Chang Ching‐Yun , Vitek Olga , Stoffel Markus , Aebersold Ruedi
Published: July 2013

The metabolic syndrome is a collection of risk factors including obesity, insulin resistance and hepatic steatosis, which occur together and increase the risk of diseases such as diabetes, cardiovascular disease and cancer. In spite of intense research, the complex etiology of insulin resistance and its association with the accumulation of triacylglycerides in the liver and with hepatic steatosis remains not completely understood. Here, we performed quantitative measurements of 144 proteins involved in the insulin‐signaling pathway and central metabolism in liver homogenates of two genetically well‐defined mouse strains C57BL/6J and 129Sv that were subjected to a sustained high‐fat diet. We used targeted mass spectrometry by selected reaction monitoring (SRM) to generate accurate and reproducible quantitation of the targeted proteins across 36 different samples (12 conditions and 3 biological replicates), generating one of the largest quantitative targeted proteomics data sets in mammalian tissues. Our results revealed rapid response to high‐fat diet that diverged early in the feeding regimen, and evidenced a response to high‐fat diet dominated by the activation of peroxisomal β‐oxidation in C57BL/6J and by lipogenesis in 129Sv mice.
Neutral buoyancy is optimal to minimize the cost of transport in horizontally swimming seals
Authors: Sato Katsufumi , Aoki Kagari , Watanabe Yuuki Y. , Miller Patrick J. O.
Published: July 2013

Flying and terrestrial animals should spend energy to move while supporting their weight against gravity. On the other hand, supported by buoyancy, aquatic animals can minimize the energy cost for supporting their body weight and neutral buoyancy has been considered advantageous for aquatic animals. However, some studies suggested that aquatic animals might use non-neutral buoyancy for gliding and thereby save energy cost for locomotion. We manipulated the body density of seals using detachable weights and floats and compared stroke efforts of horizontally swimming seals under natural conditions using animal-borne recorders. The results indicated that seals had smaller stroke efforts to swim a given speed when they were closer to neutral buoyancy. We conclude that neutral buoyancy is likely the best body density to minimize the cost of transport in horizontal swimming by seals.
A Plasmonic based Ultracompact Polarization Beam Splitter on Silicon-on-Insulator Waveguides
Authors: Tan Qilong , Huang Xuguang , Zhou Wen , Yang Kun
Published: July 2013

An ultracompact polarization beam splitter (PBS) is designed on silicon-on-insulator (SOI) platform based on the localized surface plasmons (LSPs) excited by particular polarization light. The device uses nanoscale silver cylinders as the polarization selection between two silicon waveguides of a directional coupler. The transverse-magnetic (TM) polarization light excites localized surface plasmons and is coupled into the cross port of the directional coupler with a low insert loss, while the transverse-electric (TE) polarization light is under restriction. The PBS has a coupling layer with 50 nm width and 1.1 μm length supporting broadband operation. The simulation calculations show that 22.06dB and 23.06dB of extinction ratios for the TE and TM polarizations were obtained, together with insertion losses of 0.09dB and 0.40dB.
Optimal power allocation for speech enhancement using remote wireless microphones
Authors: Srinivasan S. , Pandharipande A.
Published: July 2013

Speech capture in the presence of non‐stationary interfering signals, e.g. music or other competing talkers, is a challenging problem, and in a recent work, distributed microphones have been employed for this purpose. In this reported work, consideration is given to the problem of power allocation in a distributed microphone system, where a directional wireless microphone is placed close to each interferer and provides an estimate of the statistics of the undesired signal for suppression at the primary microphone. The optimal transmit power allocation is derived such that the mean squared error in estimating the desired signal is minimised subject to a total power constraint. It is shown that signal‐to‐noise performance improves at the primary microphone using optimum power allocation in comparison with an equal power allocation scheme.
Dependence of power amplifier backoff on resource allocation for non‐contiguous carrier aggregation
Authors: Park C.S.
Published: July 2013

The dependence of power amplifier (PA) backoff on resource allocation for non‐contiguous carrier aggregation is investigated. To be specific, assuming two non‐contiguous carriers, the power spectral density (PSD) of the third‐order intermodulation distortion (IM3) is approximated as a function of power allocation and PSD allocation. Based on the closed‐form expression, it is proven that the PSD of IM3 is maximised when the resource allocation is inversely proportional to the PSD allocation. The PA simulations verify that such resource allocation also maximises the PA backoff.
PIFA with dual‐resonance feed structure for enhancement of impedance bandwidth
Authors: Lee J. , Liu Y. , Kim H.H. , Kim H.
Published: July 2013

A planar inverted‐F antenna (PIFA) is presented, which has a dual‐resonance feed structure that enhances impedance bandwidth considerably. The proposed antenna fully covers LTE13/GSM850/GSM900 without significant modification of the antenna element fabricated in a small ground clearance. The antenna's impedance bandwidth under VSWR = 3:1 is 733–974 MHz, with a good realised efficiency.
Improved estimation scheme for disturbance due to dead time and inverter nonlinearity in inverter‐fed PMSM drive
Authors: Kim Kyeong‐Hwa
Published: July 2013

An improved estimation scheme for disturbance due to the dead time and inverter nonlinearity in an inverter‐fed permanent magnet synchronous motor (PMSM) drive is presented. The proposed scheme is based on a signal processing and harmonic component extraction and does not require any additional circuits nor parameter information. Furthermore, it is faster to estimate the disturbance as compared with the conventional method based on harmonic analysis. The effectiveness of the proposed scheme is verified through comparative simulations.
X-ray absorption fine structure study of multinuclear copper(I) thiourea mixed ligand complexes
Authors: Gaur Abhijeet , Shrivastava B. D. , Srivastava K. , Prasad J. , Raghuwanshi V. S.
Published: July 2013

X-ray absorption fine structure spectra of five copper(I) thiourea complexes [Cu4(thu)6 (NO3)4 (H2O)4] (1), [Cu4(thu)9 (NO3)4 (H2O)4] (2), [Cu2(thu)6 (SO4) H2O] (3), [Cu2(thu)5 (SO4) (H2O)3] (4), and [Cu(thu)Cl 0.5H2O] (5) have been investigated. Complexes 1 and 3 are supposed to have one type of copper centers in trigonal planar and tetrahedral environment, respectively. Complexes 2 and 4 are supposed to have two types of copper centers, one center having trigonal planar geometry and another center having tetrahedral geometry. The aim of the present work is to show how extended X-ray absorption fine structure (EXAFS) spectra of these complexes, having different types of coordination environment, can be analyzed to yield the coordination geometry around one type of copper centers present in complexes 1 and 3, and two types of copper centers present in complexes 2 and 4. The crystal structure of complex 5 is unavailable due to inability of growing its single crystals, and hence the coordination geometry of this complex has been determined from EXAFS. The structural parameters determined from the EXAFS spectra have been reported and the coordination geometry has been depicted for the metal centers present in all the five complexes. Also, the chemical shifts have been used to determine the oxidation state of copper in these complexes. The X-ray absorption near edge spectra features have also been correlated with the coordination geometry. Also, the presence of both three and four coordinated Cu(I) centers in complexes 2 and 4 has been suggested from a comparison of the intensity of the feature at 8984 eV with those of 1 and 3. Further, in case of complex 5, the high intensity of peak A at 8986.5 eV is found to correspond to the presence of Cl coordinated to the copper center.
Parallel cascade selection molecular dynamics (PaCS-MD) to generate conformational transition pathway
Authors: Harada Ryuhei , Kitao Akio
Published: July 2013

Parallel Cascade Selection Molecular Dynamics (PaCS-MD) is proposed as a molecular simulation method to generate conformational transition pathway under the condition that a set of “reactant” and “product” structures is known a priori. In PaCS-MD, the cycle of short multiple independent molecular dynamics simulations and selection of the structures close to the product structure for the next cycle are repeated until the simulated structures move sufficiently close to the product. Folding of 10-residue mini-protein chignolin from the extended to native structures and open-close conformational transition of T4 lysozyme were investigated by PaCS-MD. In both cases, tens of cycles of 100-ps MD were sufficient to reach the product structures, indicating the efficient generation of conformational transition pathway in PaCS-MD with a series of conventional MD without additional external biases. Using the snapshots along the pathway as the initial coordinates, free energy landscapes were calculated by the combination with multiple independent umbrella samplings to statistically elucidate the conformational transition pathways.
Measurement method for determining the magnetic hysteresis effects of reluctance actuators by evaluation of the force and flux variation
Authors: Vrijsen N. H. , Jansen J. W. , Compter J. C. , Lomonova E. A.
Published: July 2013

A measurement method is presented which identifies the magnetic hysteresis effects present in the force of linear reluctance actuators. The measurement method is applied to determine the magnetic hysteresis in the force of an E-core reluctance actuator, with and without pre-biasing permanent magnet. The force measurements are conducted with a piezoelectric load cell (Kistler type 9272). This high-bandwidth force measurement instrument is identified in the frequency domain using a voice-coil actuator that has negligible magnetic hysteresis and eddy currents. Specifically, the phase delay between the current and force of the voice-coil actuator is used for the calibration of the measurement instrument. This phase delay is also obtained by evaluation of the measured force and flux variation in the E-core actuator, both with and without permanent magnet on the middle tooth. The measured magnetic flux variation is used to distinguish the phase delay due to magnetic hysteresis from the measured phase delay between the current and the force of the E-core actuator. Finally, an open loop steady-state ac model is presented that predicts the magnetic hysteresis effects in the force of the E-core actuator.
Large magnetoresistance in high mobility topological insulator Bi2Se3
Authors: Yan Yuan , Wang Li-Xian , Yu Da-Peng , Liao Zhi-Min
Published: July 2013

We report the magnetotransport properties of individual Bi2Se3 nanoplates. The carrier Hall mobility is up to 104 cm2/Vs. A large positive linear magnetoresistance (MR) approaching to 400% without sign of saturation was observed at 14 T. By angular dependence measurements, we demonstrate that the linear MR originates from a two-dimensional transport. Furthermore, by comparing the Hall mobility and longitudinal resistance under different temperatures, we give very clear evidence that reveals the close relationship between magnetoresistance and mobility.
Latch-up based bidirectional npn selector for bipolar resistance-change memory
Authors: Kim Sungho , Moon Dong-Il , Lu Wei , Hwan Kim Dae , Myong Kim Dong , Choi Yang-Kyu , Choi Sung-Jin
Published: July 2013

A vertically integrated latch-up based n-p-n bidirectional diode, which is analogous to an open-base bipolar junction transistor, is demonstrated for bipolar resistance-change memory selector application. A maximum current density of >50 MA/cm2 and a selectivity of >104 are observed at a fast switching speed of within 10 ns. The high selectivity as a consequence of the sudden latch-up process is feasible owing to the positive-feedback process initiated by impact ionization. The optimization of the turn-on voltage is comprehensively investigated by numerical device simulation, which ensures the promising potential of the latch-up based selector device.
Mechanism of Schottky barrier height modulation by thin dielectric insertion on n-type germanium
Authors: Tsui Bing-Yue , Kao Ming-Hong
Published: July 2013

Although high channel electron mobility has been reported after some passivation techniques, the performance of n-channel Ge metal-oxide-semiconductor field-effect transistor is still limited by the high Schottky barrier height at the metal/n-Ge contact interface, which comes from the Fermi level pinning effect. Recent experiments demonstrated that the Schottky barrier height can be reduced by inserting a thin dielectric layer between metal and Ge. However, the mechanism has not been well clarified. In this paper, the metal induced gap state model, the dipole layer model, and the fixed charge model are verified by varying contact metals, dielectric thicknesses, as well as the annealing temperatures. The pinning factor is improved slightly by dielectric insertion but its value is independent of the dielectric thickness and is still much lower than the ideal value of the non-pinning case. This pinning effect is consistent with the Fermi level pinning at the metal/TiO2 interface. After thermal process, no interfacial layer forms at the TiO2/Ge interface and the TiO2 crystallizes gradually after annealing but the Schottky barrier height increases. Since the amount of fixed charges in the thin dielectric layer estimated from a metal-insulator-semiconductor structure is about 2 × 1011 cm−2 and is insufficient to produce the observed 0.5 eV Schottky barrier height reduction, it is thus recommended that the main mechanism comes from the change of interface dipoles and the annealing effect is attributed to the short-range ordering of the TiO2 layer. Furthermore, dielectric with low conduction band offset which has good thermal stability should be explored.
Broadband external cavity tuning in the 3-4 μm window
Authors: Riedi Sabine , Hugi Andreas , Bismuto Alfredo , Beck Mattias , Faist Jérôme
Published: July 2013

In this work, a continuous external cavity spectral tuning of 556 cm−1 in the 3–4 μm region is shown for a heterogeneous bound-to-continuum active region design based on the strain-compensated Sb-free material system. The two active regions have center wavelengths at 3.3 μm and 3.7 μm with a total modal overlap factor of 86%. We also show an effective multilayer broadband anti-reflectivity coating in the 3–4 μm region reducing the overall reflectivity over the whole tuning range below 1.4%.
Photoinduced phase transition and relaxation in bare SrTiO3 single crystals
Authors: Jin K. X. , Luo B. C. , Li Y. F. , Chen C. L. , Wu T.
Published: July 2013

The photoinduced insulator-metal phase transition and relaxation characteristics have been investigated in bare SrTiO3 single crystals. The photoinduced relaxation time constant after the irradiation shows an increase with increasing temperatures. The SrTiO3 single crystal has a cutoff wavelength and an absorption edge of spectrum at about 385 nm, which agrees well with the band gap. The photocurrent responsivity is 1.36 × 10−5 A/W at 300 nm wavelength. The relative change in resistance is more than above six orders at room temperature, possessing potential applications in ultraviolet sensitive and detecting devices.
Leptin promotes K
ATP
channel trafficking by AMPK signaling in pancreatic β-cells
Authors: Park Sun-Hyun , Ryu Shin-Young , Yu Weon-Jin , Han Young Eun , Ji Young-Sun , Oh Keunhee , Sohn Jong-Woo , Lim Ajin , Jeon Jae-Pyo , Lee Hyunsu , Lee Kyu-Hee , Lee Suk-Ho , Berggren Per-Olof , Jeon Ju-Hong , Ho Won-Kyung
Published: July 2013

Leptin is a pivotal regulator of energy and glucose homeostasis, and defects in leptin signaling result in obesity and diabetes. The ATP-sensitive potassium (K
ATP
) channels couple glucose metabolism to insulin secretion in pancreatic β-cells. In this study, we provide evidence that leptin modulates pancreatic β-cell functions by promoting K
ATP
channel translocation to the plasma membrane via AMP-activated protein kinase (AMPK) signaling. K
ATP
channels were localized mostly to intracellular compartments of pancreatic β-cells in the fed state and translocated to the plasma membrane in the fasted state. This process was defective in leptin-deficient
ob
/ob
mice, but restored by leptin treatment. We discovered that the molecular mechanism of leptin-induced AMPK activation involves canonical transient receptor potential 4 and calcium/calmodulin-dependent protein kinase kinase β. AMPK activation was dependent on both leptin and glucose concentrations, so at optimal concentrations of leptin, AMPK was activated sufficiently to induce K
ATP
channel trafficking and hyperpolarization of pancreatic β-cells in a physiological range of fasting glucose levels. There was a close correlation between phospho-AMPK levels and β-cell membrane potentials, suggesting that AMPK-dependent K
ATP
channel trafficking is a key mechanism for regulating β-cell membrane potentials. Our results present a signaling pathway whereby leptin regulates glucose homeostasis by modulating β-cell excitability.
Homologous recombination rescues ssDNA gaps generated by nucleotide excision repair and reduced translesion DNA synthesis in yeast G2 cells
Authors: Ma Wenjian , Westmoreland James W. , Resnick Michael A.
Published: July 2013

Significance

DNA damage challenges genome integrity. Bulky DNA lesions, which are subject to nucleotide-excision repair, induce homologous recombination (HR). However, because there is no direct generation of double-strand breaks (DSBs), the underlying mechanism has been obscure. By investigating UV-induced lesions in nonreplicating G2 cells of budding yeast, we found that translesion DNA synthesis (TLS) and HR are redundant in repair. Using a physical assay that detects recombination between circular sister chromatids, we establish that UV-induced recombination is not attributable to DSBs but instead is associated directly with expanded ssDNA gaps and is increased in cells defective in TLS.
Flexible frequency control of cortical oscillations enables computations required for working memory
Authors: Dipoppa Mario , Gutkin Boris S.
Published: July 2013

Cognitive effort leads to a seeming cacophony of brain oscillations. For example, during tasks engaging working memory (WM), specific oscillatory frequency bands modulate in space and time. Despite ample data correlating such modulation to task performance, a mechanistic explanation remains elusive. We propose that flexible control of neural oscillations provides a unified mechanism for the rapid and controlled transitions between the computational operations required by WM. We show in a spiking network model that modulating the input oscillation frequency sets the network in different operating modes: rapid memory access and load is enabled by the beta–gamma oscillations, maintaining a memory while ignoring distractors by the theta, rapid memory clearance by the alpha. The various frequency bands determine the dynamic gating regimes enabling the necessary operations for WM, whose succession explains the need for the complex oscillatory brain dynamics during effortful cognition.
Syntaxin1a variants lacking an N-peptide or bearing the LE mutation bind to Munc18a in a closed conformation
Authors: Colbert Karen N. , Hattendorf Douglas A. , Weiss Thomas M. , Burkhardt Pawel , Fasshauer Dirk , Weis William I.
Published: July 2013

In neurons, soluble
N
-ethylmaleimide–sensitive factor attachment receptor (SNARE) proteins drive the fusion of synaptic vesicles to the plasma membrane through the formation of a four-helix SNARE complex. Members of the Sec1/Munc18 protein family regulate membrane fusion through interactions with the syntaxin family of SNARE proteins. The neuronal protein Munc18a interacts with a closed conformation of the SNARE protein syntaxin1a (Syx1a) and with an assembled SNARE complex containing Syx1a in an open conformation. The N-peptide of Syx1a (amino acids 1–24) has been implicated in the transition of Munc18a-bound Syx1a to Munc18a-bound SNARE complex, but the underlying mechanism is not understood. Here we report the X-ray crystal structures of Munc18a bound to Syx1a with and without its native N-peptide (Syx1aΔN), along with small-angle X-ray scattering (SAXS) data for Munc18a bound to Syx1a, Syx1aΔN, and Syx1a L165A/E166A (LE), a mutation thought to render Syx1a in a constitutively open conformation. We show that all three complexes adopt the same global structure, in which Munc18a binds a closed conformation of Syx1a. We also identify a possible structural connection between the Syx1a N-peptide and SNARE domain that might be important for the transition of closed-to-open Syx1a in SNARE complex assembly. Although the role of the N-peptide in Munc18a-mediated SNARE complex assembly remains unclear, our results demonstrate that the N-peptide and LE mutation have no effect on the global conformation of the Munc18a–Syx1a complex.
Two-codon T-box riboswitch binding two tRNAs
Authors: Saad Nizar Y. , Stamatopoulou Vassiliki , Brayé Mélanie , Drainas Denis , Stathopoulos Constantinos , Becker Hubert Dominique
Published: July 2013

T-box riboswitches control transcription of downstream genes through the tRNA-binding formation of terminator or antiterminator structures. Previously reported T-boxes were described as single-specificity riboswitches that can bind specific tRNA anticodons through codon–anticodon interactions with the nucleotide triplet of their specifier loop (SL). However, the possibility that T-boxes might exhibit specificity beyond a single tRNA had been overlooked. In
Clostridium acetobutylicum
, the T-box that regulates the operon for the essential tRNA-dependent transamidation pathway harbors a SL with two potential overlapping codon positions for tRNA
Asn
and tRNA
Glu
. To test its specificity, we performed extensive mutagenic, biochemical, and chemical probing analyses. Surprisingly, both tRNAs can efficiently bind the SL in vitro and in vivo. The dual specificity of the T-box is allowed by a single base shift on the SL from one overlapping codon to the next. This feature allows the riboswitch to sense two tRNAs and balance the biosynthesis of two amino acids. Detailed genomic comparisons support our observations and suggest that “flexible” T-box riboswitches are widespread among bacteria, and, moreover, their specificity is dictated by the metabolic interconnection of the pathways under control. Taken together, our results support the notion of a genome-dependent codon ambiguity of the SLs. Furthermore, the existence of two overlapping codons imposes a unique example of tRNA-dependent regulation at the transcriptional level.
Phylogeny and tempo of diversification in the superradiation of spiny-rayed fishes
Authors: Near Thomas J. , Dornburg Alex , Eytan Ron I. , Keck Benjamin P. , Smith W. Leo , Kuhn Kristen L. , Moore Jon A. , Price Samantha A. , Burbrink Frank T. , Friedman Matt , Wainwright Peter C.
Published: July 2013

Spiny-rayed fishes, or acanthomorphs, comprise nearly one-third of all living vertebrates. Despite their dominant role in aquatic ecosystems, the evolutionary history and tempo of acanthomorph diversification is poorly understood. We investigate the pattern of lineage diversification in acanthomorphs by using a well-resolved time-calibrated phylogeny inferred from a nuclear gene supermatrix that includes 520 acanthomorph species and 37 fossil age constraints. This phylogeny provides resolution for what has been classically referred to as the “bush at the top” of the teleost tree, and indicates acanthomorphs originated in the Early Cretaceous. Paleontological evidence suggests acanthomorphs exhibit a pulse of morphological diversification following the end Cretaceous mass extinction; however, the role of this event on the accumulation of living acanthomorph diversity remains unclear. Lineage diversification rates through time exhibit no shifts associated with the end Cretaceous mass extinction, but there is a global decrease in lineage diversification rates 50 Ma that occurs during a period when morphological disparity among fossil acanthomorphs increases sharply. Analysis of clade-specific shifts in diversification rates reveal that the hyperdiversity of living acanthomorphs is highlighted by several rapidly radiating lineages including tunas, gobies, blennies, snailfishes, and Afro-American cichlids. These lineages with high diversification rates are not associated with a single habitat type, such as coral reefs, indicating there is no single explanation for the success of acanthomorphs, as exceptional bouts of diversification have occurred across a wide array of marine and freshwater habitats.
Asymmetric thymocyte death underlies the CD4:CD8 T-cell ratio in the adaptive immune system
Authors: Sinclair Charles , Bains Iren , Yates Andrew J. , Seddon Benedict
Published: July 2013

Significance

Thymocytes express a diverse repertoire of T-cell antigen receptors. Stringent selection processes eliminate autoreactive cells and guide useful thymocytes to develop into CD4 or CD8 lineages. Development always generates more CD4 than CD8 T cells, but it is not understood why. Our study used mathematics to investigate the basis of this asymmetric lineage development. Although similar numbers of CD4 and CD8 precursors start selection, our analysis revealed unexpectedly high death rates in developing thymocytes. In particular, CD8 precursors were more susceptible to death than CD4 lineage cells, and this was a major contributor to the high CD4:CD8 ratio of development.
Crop manuring and intensive land management by Europe’s first farmers
Authors: Bogaard Amy , Fraser Rebecca , Heaton Tim H. E. , Wallace Michael , Vaiglova Petra , Charles Michael , Jones Glynis , Evershed Richard P. , Styring Amy K. , Andersen Niels H. , Arbogast Rose-Marie , Bartosiewicz László , Gardeisen Armelle , Kanstrup Marie , Maier Ursula , Marinova Elena , Ninov Lazar , Schäfer Marguerita , Stephan Elisabeth
Published: July 2013

The spread of farming from western Asia to Europe had profound long-term social and ecological impacts, but identification of the specific nature of Neolithic land management practices and the dietary contribution of early crops has been problematic. Here, we present previously undescribed stable isotope determinations of charred cereals and pulses from 13 Neolithic sites across Europe (dating
ca
. 5900–2400 cal B.C.), which show that early farmers used livestock manure and water management to enhance crop yields. Intensive manuring inextricably linked plant cultivation and animal herding and contributed to the remarkable resilience of these combined practices across diverse climatic zones. Critically, our findings suggest that commonly applied paleodietary interpretations of human and herbivore δ
15
N values have systematically underestimated the contribution of crop-derived protein to early farmer diets.
Cognitive abnormalities and hippocampal alterations in monoamine oxidase A and B knockout mice
Authors: Singh Chanpreet , Bortolato Marco , Bali Namrata , Godar Sean C. , Scott Anna L. , Chen Kevin , Thompson Richard F. , Shih Jean C.
Published: July 2013

The monoamine oxidase isoenzymes (MAOs) A and B play important roles in the homeostasis of monoaminergic neurotransmitters. The combined deficiency of MAO A and B results in significantly elevated levels of serotonin (5-hydroxytryptamine), norepinephrine, dopamine, and β-phenylethylamine; in humans and mice, these neurochemical changes are accompanied by neurodevelopmental perturbations as well as autistic-like responses. Ample evidence indicates that normal levels of monoamines in the hippocampus, amygdala, frontal cortex, and cerebellum are required for the integrity of learning and memory. Thus, in the present study, the cognitive status of MAO A/B knockout (KO) mice was examined with a wide array of behavioral tests. In comparison with male wild-type littermates, MAO A/B KO mice exhibited abnormally high and overgeneralized fear conditioning and enhanced eye-blink conditioning. These alterations were accompanied by significant increases in hippocampal long-term potentiation and alterations in the relative expression of NMDA glutamate receptor subunits. Our data suggest that chronic elevations of monoamines, because of the absence of MAO A and MAO B, cause functional alterations that are accompanied with changes in the cellular mechanisms underlying learning and memory. The characteristics exhibited by MAO A/B KO mice highlight the potential of these animals as a useful tool to provide further insight into the molecular bases of disorders associated with abnormal monoaminergic profiles.
EVI1 oncoprotein interacts with a large and complex network of proteins and integrates signals through protein phosphorylation
Authors: Bard-Chapeau Emilie A. , Gunaratne Jayantha , Kumar Pankaj , Chua Belinda Q. , Muller Julius , Bard Frederic A. , Blackstock Walter , Copeland Neal G. , Jenkins Nancy A.
Published: July 2013

Significance

Although ecotropic viral integration site 1 (EVI1) oncogenic transcription factor was discovered in 1988, its molecular functions and regulations are still underexplored. Through characterization of few EVI1-interacting proteins, EVI1 was identified as dynamic modulator of transcription and chromatin remodeling. We used proteomics approaches to define the EVI1 interactome. We found associations of EVI1 with not only transcriptional regulators, but also components of signaling pathways, DNA repair, DNA recombination, and mitosis complexes. We also identified functional EVI1 phosphorylation sites modified by casein-kinase II and protein phosphatase-1α that impact EVI1 activity. Thus, our study provides critical molecular insights on EVI1 action and regulation.
Processing visual metaphor
Authors: Šorm Ester , Steen Gerard J.
Published: July 2013

This article explores the mental operations people undertake when they encounter a visual metaphor. First, an integrated theoretical model of visual metaphor processing is proposed. The model is then empirically evaluated: in a think aloud task, six participants were presented with twelve pictures containing visual metaphor and asked to verbalize their thoughts as they looked at the pictures. The experimental materials represented four different genres: political cartoons, magazine advertisements, educational illustrations and paintings. The findings enable a more precise description of what happens when people attempt to reach understanding of visual metaphor. The results have implications for building theory around visual metaphor processing, as well as empirical research on the interpretation of visual metaphor.
UK media representations of Carbon Capture and Storage
Authors: Nerlich Brigitte , Jaspal Rusi
Published: July 2013

Carbon Capture and Storage (CCS) is a climate change mitigation technology which has had a rather chequered history in British policy making and in the British public sphere. This article deals with the neglected topic of representations of CCS in the British media and their possible impact on public perceptions and public policy. Public perception of CCS is shaped in part by the media which provide tools for making sense of complex technological and political issues such as CCS. This article compares articles on CCS in two UK newspapers, one national (“The Times”) and one regional (“The Aberdeen Press and Journal”) in 2011, a year during which some of the last battles over CCS demonstration projects were fought. It applies frame and metaphor analysis to a corpus of 150 articles. Findings reveal that during 2011 CCS coverage moved through a cycle of hype and disillusionment, with both newspapers reaching a trough of disappointment at the end of 2011. It will be difficult to reignite interest in CCS in this context, both in terms of media and public attention, and in terms of policy and investment. Regional confidence in national CCS policy in particular will be difficult to recover.
Variación sociosituacional de la colocación del sujeto pronominal en textos conversacionales
Authors: Serrano María José
Published: July 2013

La colocación del sujeto con respecto al verbo constituye un caso de variación notablemente estudiado en la gramática española. En este trabajo nos proponemos desarrollar su análisis incorporando las propiedades cognitivas que caracterizan a esa variación como la prominencia cognitiva y la informatividad textual. Las variantes preverbal y posverbal en géneros conversacionales del Corpus Conversacional del Español de Canarias, coaparecen con factores sociales, situacionales y comunicativos tales como la función que adopta el hablante en la interacción (transaccional o interpersonal) y el sexo/género. Esto da lugar a la construcción de distintos estilos comunicativos basados en las dimensiones graduales de la objetividad-subjetividad que se distribuyen de forma desigual entre tales categorías.
Acquiring plurality in directional verbs
Authors: Hou Lynn Y-S.
Published: July 2013

Little is known about when and how children acquire plurality for directional verbs in ASL and other signed languages. This paper reports on an experimental study of 11 deaf native-signing children’s acquisition of ‘plural verb agreement’ or plural forms of directional verbs in American Sign Language. Eleven native-signing deaf adults were also tested. An elicitation task explored how children (aged 3;4 to 5;11) and adults marked directional verbs for plurality. The children also participated in an imitation task. Adults marked directional verbs for plurality significantly more often than children. However, adults also omitted plurality from directional verbs, utilizing alternative strategies to mark plural referents significantly more often than did children. Children across all ages omitted plurality, suggesting that the omission is attributable to both the conceptual complexity of plural markers and the optionality of number-marking. Directionality may not be best analyzed as a morphosyntactic phenomenon analogous to verb agreement morphology in spoken languages.
Handshape is the hardest path in Portuguese Sign Language acquisition
Authors: Carmo Patrícia do , Mineiro Ana , Branco Joana Castelo , Müller de Quadros Ronice , Castro-Caldas Alexandre
Published: July 2013

Sign languages have only been acknowledged as true languages in the second half of the 20th century. Studies on their ontogenesis are recent and include mostly comparative approaches to spoken language and sign language acquisition. Studies on sign language acquisition show that of the manual phonological parameters, handshape is the one which is acquired last. This study reports the findings of a first pilot study on Portuguese Sign Language (Língua Gestual Portuguesa — LGP) acquisition, focusing on a Deaf child from 10 months until 24 months of age, and it confirms the pattern previously described for other sign languages. We discuss possible reasons why handshape is harder to acquire, which relate to neuromotor development and perceptual issues, and we suggest that auditory deprivation might delay the acquisition of fine motor skills.
State and religion in a revolutionary era: perspectives and demands of the Islamic awakening
Authors: Al-Sayyid Ridwan
Published: July 2013

This paper tackles the relationship between Islam and the state in light of the ongoing revolutions. It focuses on two perspectives: the Islamists’ claim that the Shari’a and not the umma (community) are the source of legitimacy in the evolving regimes; and that it is the duty of the state to protect religion and apply the Shari’a. The main disadvantage of these propositions is that they preclude the Umma both from political power and Shari’a, thus pitting it against these two assets which become manipulated to its disadvantage by those holding power. On the other hand, an open-minded and reformist Islamic perspective believes in people regaining the prerogative to rule themselves, guided by their intellect and the public good. The main call for the Arab uprisings is to quit political Islam, which seems to be the major threat to religion, and dangerously divisive for societies.
Cell cycle regulation of Greatwall kinase nuclear localization facilitates mitotic progression
Authors: Wang Peng , Galan Jacob A. , Normandin Karine , Bonneil Éric , Hickson Gilles R. , Roux Philippe P. , Thibault Pierre , Archambault Vincent
Published: July 2013

Cell division requires the coordination of critical protein kinases and phosphatases. Greatwall (Gwl) kinase activity inactivates PP2A-B55 at mitotic entry to promote the phosphorylation of cyclin B–Cdk1 substrates, but how Gwl is regulated is poorly understood. We found that the subcellular localization of Gwl changed dramatically during the cell cycle in Drosophila. Gwl translocated from the nucleus to the cytoplasm in prophase. We identified two critical nuclear localization signals in the central, poorly characterized region of Gwl, which are required for its function. The Polo kinase associated with and phosphorylated Gwl in this region, promoting its binding to 14-3-3ε and its localization to the cytoplasm in prophase. Our results suggest that cyclin B–Cdk1 phosphorylation of Gwl is also required for its nuclear exclusion by a distinct mechanism. We show that the nucleo-cytoplasmic regulation of Gwl is essential for its functions in vivo and propose that the spatial regulation of Gwl at mitotic entry contributes to the mitotic switch.
Kinesin-5/Eg5 is important for transport of CARTS from the trans-Golgi network to the cell surface
Authors: Wakana Yuichi , Villeneuve Julien , van Galen Josse , Cruz-Garcia David , Tagaya Mitsuo , Malhotra Vivek
Published: July 2013

Here we report that the kinesin-5 motor Klp61F, which is known for its role in bipolar spindle formation in mitosis, is required for protein transport from the Golgi complex to the cell surface in Drosophila S2 cells. Disrupting the function of its mammalian orthologue, Eg5, in HeLa cells inhibited secretion of a protein called pancreatic adenocarcinoma up-regulated factor (PAUF) but, surprisingly, not the trafficking of vesicular stomatitis virus G protein (VSV-G) to the cell surface. We have previously reported that PAUF is transported from the trans-Golgi network (TGN) to the cell surface in specific carriers called CARTS that exclude VSV-G. Inhibition of Eg5 function did not affect the biogenesis of CARTS; however, their migration was delayed and they accumulated near the Golgi complex. Altogether, our findings reveal a surprising new role of Eg5 in nonmitotic cells in the facilitation of the transport of specific carriers, CARTS, from the TGN to the cell surface.
The nonlinear heat equation with high order mixed derivatives of the Dirac delta as initial values
Authors: Tayachi Slim , Weissler Fred
Published: July 2013

In this paper we prove local existence of solutions of the nonlinear heat equation
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="u Subscript t Baseline equals normal upper Delta u plus StartAbsoluteValue u EndAbsoluteValue Superscript alpha Baseline u comma t element-of left-parenthesis 0 comma upper T right-parenthesis comma x element-of double-struck upper R Superscript upper N Baseline comma">

u
t

=
Δ
u
+

|

u

|

α

u
,

t
∈
(
0
,
T
)
,

x
∈

R

N

,

u_t = \Delta u + |u|^\alpha u, \; t\in (0,T),\; x\in \mathbb {R}^N,

with initial value
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="u left-parenthesis 0 right-parenthesis equals upper K partial-differential Subscript 1 Baseline partial-differential Subscript 2 Baseline dot dot dot partial-differential Subscript m Baseline delta comma upper K not-equals 0 comma m element-of StartSet 1 comma 2 comma midline-horizontal-ellipsis comma upper N EndSet comma 0 greater-than alpha greater-than 2 slash left-parenthesis upper N plus m right-parenthesis">

u
(
0
)
=
K

∂

1

∂

2

⋅
⋅
⋅

∂

m

δ
,

K
≠
0
,

m
∈
{
1
,

2
,

⋯
,

N
}
,

0
>
α
>
2

/

(
N
+
m
)

u(0)=K\partial _{1}\partial _{2}\cdot \cdot \cdot \partial _{m}\delta ,\; K\not =0,\; m\in \{1,\; 2,\; \cdots ,\; N\},\; 0>\alpha >2/(N+m)

and

δ
\delta

is the Dirac distribution. In particular, this gives a local existence result with an initial value in a high order negative Sobolev space

H

s
,
q

(

R

N

)

H^{s,q}(\mathbb {R}^N)

with

s
≤
−
2.

s\leq -2.

As an application, we prove the existence of initial values

u
0

=
λ
f

u_0 = \lambda f

for which the resulting solution blows up in finite time if

λ
>
0

\lambda >0

is sufficiently small. Here,

f
f

satisfies in particular
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="f element-of upper C 0 left-parenthesis double-struck upper R Superscript upper N Baseline right-parenthesis intersection upper L Superscript 1 Baseline left-parenthesis double-struck upper R Superscript upper N Baseline right-parenthesis">

f
∈

C
0

(

R

N

)
∩

L
1

(

R

N

)

f\in C_0(\mathbb {R}^N)\cap L^1(\mathbb {R}^N)

and is anti-symmetric with respect to

x
1

,

x
2

,

⋯
,

x
m

.

x_1,\; x_2,\; \cdots ,\; x_m.

Moreover, we require

∫

R

N

x
1

⋯

x
m

f
(
x
)
d
x
≠
0

\int _{\mathbb {R}^N} x_1\cdots x_mf(x) dx\not =0

. This extends the known “small lambda” blow up results which require either that

∫

R

N

f
(
x
)
d
x
≠
0

\int _{\mathbb {R}^N}f(x) dx\not =0

(Dickstein (2006)) or

∫

R

N

x
1

f
(
x
)
d
x
≠
0

\int _{\mathbb {R}^N} x_1f(x) dx\not =0

(Ghoul (2011), (2012)).