bluuebunny/crossref_metadata_2025 huggingface dataset:
Automatic stellar spectral parameterization pipeline for LAMOST survey
Authors: Wu Yue , Du Bing , Luo Ali , Zhao Yongheng , Yuan Hailong
Published: July 2015

The Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) project performed its five year formal survey since Sep. 2012, already fulfilled the pilot survey and the 1st two years general survey with an output - spectroscopic data archive containing more than 4.1 million observations. One of the scientific objectives of the project is for better understanding the structure and evolution of the Milky Way. Thus, credible derivation of the physical properties of the stars plays a key role for the exploration. We developed and implemented the LAMOST stellar parameter pipeline (LASP) which can automatically determine the fundamental stellar atmospheric parameters (effective temperature Teff, surface gravity log g, metallicity [Fe/H], radial velocity Vr) for late A, FGK type stars observed during the survey. An overview of the LASP, including the strategy, the algorithm and the process is presented in this work.
Towards a better understanding of galaxy clusters
Authors: Viana Pedro T. P.
Published: July 2015

Observational data on clusters of galaxies holds relevant information that can be used to determine the relative plausibility of different models for the large-scale evolution of the Universe, or estimate the joint posterior probability distribution function of the parameters that pertain to each model. Within the next few years, several surveys of the sky will yield large galaxy cluster catalogues. In order to make use of the vast amount of information they will contain, their selection functions will have to be properly understood. We argue this, as well as the estimation of the full joint posterior probability distribution function of the most relevant cluster properties, can be best achieved in the framework of bayesian statistics.
Robust Constraint of Luminosity Function Evolution through MCMC Sampling
Authors: Kurinsky Noah , Sajina Anna
Published: July 2015

We present a new galaxy survey simulation package, which combines the power of Markov Chain Monte Carlo (MCMC) sampling with a robust and adaptable model of galaxy evolution. The aim of this code is to aid in the characterization and study of new and existing galaxy surveys. In this paper we briefly describe the MCMC implementation and the survey simulation methodology and associated tools. A test case of this full suite was to constrain the evolution of the IR Luminosity Function (LF) based on the HerMES (Herschel SPIRE) survey of the Spitzer First Look Survey field. The initial results are consistent with previous studies, but our more general approach should be of wider benefit to the community.
Cluster strong lensing: a new strategy for testing cosmology with simulations
Authors: Killedar M. , Borgani S. , Fabjan D. , Dolag K. , Granato G. , Meneghetti M. , Planelles S. , Ragone-Figueroa C.
Published: July 2015

Comparisons between observed and predicted strong lensing properties of galaxy clusters have been used to claim either tension or consistency with ΛCDM cosmology. However, standard approaches to such tests are unable to quantify the preference for one cosmology over another. We advocate a Bayesian approach whereby the parameters defining the scaling relation between Einstein radii and cluster mass are treated as the observables. We demonstrate a method of estimating the likelihood for observing these parameters under the ΛCDM framework, using the X-ray selected z > 0.5 MACS clusters as a case in point and employing both N-body and hydrodynamic simulations of clusters. We account for cluster lens triaxiality within the modelling of the likelihood function. Cluster selection criteria is found to play as important a role as the uncertainty related to the description of star formation and feedback.
Detectability of Torus Topology
Authors: Fabre Ophélia , Prunet Simon , Uzan Jean-Philippe
Published: July 2015

The global shape, or topology, of the universe is not constrained by the equations of General Relativity, which only describe the local universe. As a consequence, the boundaries of space are not fixed and topologies different from the trivial infinite Euclidean space are possible. The cosmic microwave background (CMB) is the most efficient tool to study topology and test alternative models. Multi-connected topologies, such as the 3-torus, are of great interest because they are anisotropic and allow us to test a possible violation of isotropy in CMB data. We show that the correlation function of the coefficients of the expansion of the temperature and polarization anisotropies in spherical harmonics encodes a topological signature. This signature can be used to distinguish an infinite space from a multi-connected space on sizes larger than the diameter of the last scattering surface (DLSS). With the help of the Kullback-Leibler divergence, we set the size of the edge of the biggest distinguishable torus with CMB temperature fluctuations and E-modes of polarization to 1.15 DLSS. CMB temperature fluctuations allow us to detect universes bigger than the observable universe, whereas E-modes are efficient to detect universes smaller than the observable universe.
Statistics of cosmological fields
Authors: Matarrese Sabino
Published: July 2015

The general problem of the statistics of the primordial curvature perturbation field in cosmology is reviewed. The search for non-Gaussian signatures in cosmological perturbations, originated from inflation in the early Universe is discussed both from the theoretical point of view and in connection with constraints coming from recent observations and future prospects for observing/constraining them.
Considerations in the Interpretation of Cosmological Anomalies
Authors: Peiris Hiranya V.
Published: July 2015

Anomalies drive scientific discovery – they are associated with the cutting edge of the research frontier, and thus typically exploit data in the low signal-to-noise regime. In astronomy, the prevalence of systematics –- both “known unknowns” and “unknown unknowns” – combined with increasingly large datasets, the widespread use of ad hoc estimators for anomaly detection, and the “look-elsewhere” effect, can lead to spurious false detections. In this informal note, I argue that anomaly detection leading to discoveries of new physics requires a combination of physical understanding, careful experimental design to avoid confirmation bias, and self-consistent statistical methods. These points are illustrated with several concrete examples from cosmology.
Errors on errors – Estimating cosmological parameter covariance
Authors: Joachimi Benjamin , Taylor Andy
Published: July 2015

Current and forthcoming cosmological data analyses share the challenge of huge datasets alongside increasingly tight requirements on the precision and accuracy of extracted cosmological parameters. The community is becoming increasingly aware that these requirements not only apply to the central values of parameters but, equally important, also to the error bars. Due to non-linear effects in the astrophysics, the instrument, and the analysis pipeline, data covariance matrices are usually not well known a priori and need to be estimated from the data itself, or from suites of large simulations. In either case, the finite number of realisations available to determine data covariances introduces significant biases and additional variance in the errors on cosmological parameters in a standard likelihood analysis. Here, we review recent work on quantifying these biases and additional variances and discuss approaches to remedy these effects.
Nonparametric kernel methods for curve estimation and measurement errors
Authors: Delaigle Aurore
Published: July 2015

We consider the problem of estimating an unknown density or regression curve from data. In the parametric setting, the curve to estimate is modelled by a function which is known up to the value of a finite number of parameters. We consider the nonparametric setting, where the curve is not modelled a priori. We focus on kernel methods, which are popular nonparametric techniques that can be used for both density and regression estimation. While these methods are appropriate when the data are observed accurately, they cannot be directly applied to astronomical data, which are often measured with a certain degree of error. It is well known in the statistics literature that when the observations are measured with errors, nonparametric procedures become biased, and need to be adjusted for the errors. Correction techniques have been developed, and are often referred to as deconvolution methods. We introduce those methods, in both the homoscedastic and heteroscedastic error cases, and discuss their practical implementation.
The Role of Statistics and Statisticians in the Future of Astrostatistics
Authors: Hilbe Joseph M.
Published: July 2015

Given the generic definition of statistics, it is clear that astronomers have engaged in statistical analysis of some variety since astronomy first emerged as a science. However, from the early nineteenth century until the beginning of the twenty-first the two disciplines have been somewhat estranged – there was no formal relationship between the two. This has now changed, as is evidenced by the recent creation of the International Astrostatistics Association (IAA), the ISI astrostatistics committee, astrostatistics working groups authorized by the IAU and AAS, and this Symposium. The challenge for us to come is in establishing how statisticians and astronomers relate in developing the discipline of astrostatistics. I shall propose a direction for how the discipline can progress in both the short term and well as for future generations of astrostatisticians.
Estimating the distribution of Galaxy Morphologies on a continuous space
Authors: Vinci Giuseppe , Freeman Peter , Newman Jeffrey , Wasserman Larry , Genovese Christopher
Published: July 2015

The incredible variety of galaxy shapes cannot be summarized by human defined discrete classes of shapes without causing a possibly large loss of information. Dictionary learning and sparse coding allow us to reduce the high dimensional space of shapes into a manageable low dimensional continuous vector space. Statistical inference can be done in the reduced space via probability distribution estimation and manifold estimation.
Testing the mutual consistency of different supernovae surveys
Authors: Karpenka N.V. , Feroz F. , Hobson M.P.
Published: July 2015

It is now common practice to constrain cosmological parameters using supernovae (SNe) catalogues constructed from several different surveys. Before performing such a joint analysis, however, one should check that parameter constraints derived from the individual SNe surveys that make up the catalogue are mutually consistent. We describe a statistically-robust mutual consistency test, which we calibrate using simulations, and apply it to each pairwise combination of the surveys making up, respectively, the UNION2 catalogue and the very recent JLA compilation by Betoule et al. We find no inconsistencies in the latter case, but conclusive evidence for inconsistency between some survey pairs in the UNION2 catalogue.
Princicpal Component Analysis of type II supernova V band light-curves
Authors: Galbany Lluís
Published: July 2015

We present a Principal Component Analysis (PCA) of the V band light-curves of a sample of more than 100 nearby Core collapse supernovae (CC SNe) from [Anderson et al. (2014)]. We used different reference epochs in order to extract the common properties of these light-curves and searched for correlations to some physical parameters such as the burning of 56Ni, and morphological light-curve parameters such as the length of the plateau, the stretch of the light-curve, and the decrements in brightness after maximum and after the plateau. We also used these similarities to create SNe II light-curve templates that will be used in the future for standardize these objects and determine cosmological distances.
The impact of small absorbers, galactic neutral hydrogen & X-rays on 1-point statistics of the 21-cm line.
Authors: Watkinson C. A. , Pritchard J. R. , Mesinger A. , Sobacchi E.
Published: July 2015

We discuss a selection of semi-numerical simulations of reionization whose analysis investigates the effect of small absorbing systems, neutral hydrogen within galaxies and the efficiency with which galaxies produce X-rays. We focus on the consequences for both observing the 21–cm 1-point statistics and their interpretation.
A Supervoid Explanation of the Cosmic Microwave Background Cold Spot
Authors: Finelli F. , García-Bellido J. , Kovács A. , Paci F. , Szapudi I.
Published: July 2015

The Cold Spot is an anomalously cold region in the Cosmic Microwave Background (Vielva et al. 2004), either caused by a structure in the line of sight or could be of primordial origin. We search for a supervoid aligned with the Cold Spot region, filling the gap in redshift at z<0.3 which has never been explored in details. We find a large projected under density in the recently constructed WISE-2MASS catalogue, whose median redshift is z ≃ 0.14, with an angular size of 30 degrees. We show that a spherically symmetric Lemaitre-Tolman-Bondi (LTB) void model can simultaneously fit the δgal/b=δ2D≃ −0.12 underdensity in the WISE-2MASS catalogue, and the Cold Spot as observed by both the WMAP and Planck satellites. Such an LTB supervoid gives a plausible explanation of the Cold Spot anomaly, and is preferred over the null hypothesis or a texture model.
Understanding Cosmological Measurements with a large number of mock galaxy catalogues.
Authors: Manera M. , Percival W. J. , Ross Ashley , Tojeiro R. , Samushia L. , Howlett C. , Vargas-Magaña M. , Burden A. ,   for the SDSS-III BOSS Galaxy Working Group
Published: July 2015

Mock galaxy catalogues are essential to the error analysis of cosmological measurements from big galaxy surveys covering thousands of square degrees in the sky, like BOSS, WiggleZ, DES, or Euclid. The PTHalos mock galaxy catalogues were used in the BOSS survey to analyse the BAO measurement from the CMASS (z∼ 0.57) and LOWZ (z∼ 0.32) galaxy samples, which provided the best estimate to date of the cosmic distance scale from galaxy surveys at these redshifts. We review the PTHalos mocks galaxy catalogues and their key contributions to these analyses.
Low/High Redshift Classification of Emission Line Galaxies in the HETDEX survey
Authors: Acquaviva Viviana , Gawiser Eric , Leung Andrew S. , Martin Mario R.
Published: July 2015

We discuss different methods to separate high- from low-redshift galaxies based on a combination of spectroscopic and photometric observations. Our baseline scenario is the Hobby-Eberly Telescope Dark Energy eXperiment (HETDEX) survey, which will observe several hundred thousand Lyman Alpha Emitting (LAE) galaxies at 1.9 < z < 3.5, and for which the main source of contamination is [OII]-emitting galaxies at z < 0.5. Additional information useful for the separation comes from empirical knowledge of LAE and [OII] luminosity functions and equivalent width distributions as a function of redshift. We consider three separation techniques: a simple cut in equivalent width, a Bayesian separation method, and machine learning algorithms, including support vector machines. These methods can be easily applied to other surveys and used on simulated data in the framework of survey planning.
21cm Cosmology
Authors: Santos Mario G. , Alonso David , Bull Philip , Camera Stefano , Ferreira Pedro G.
Published: July 2015

A new generation of radio telescopes with unprecedented capabilities for astronomy and fundamental physics will be in operation over the next few years. With high sensitivities and large fields of view, they are ideal for cosmological applications. We discuss their uses for cosmology focusing on the observational technique of HI intensity mapping, in particular at low redshifts (z < 4). This novel observational window promises to bring new insights for cosmology, in particular on ultra-large scales and at a redshift range that can go beyond the dark energy domination epoch. In terms of standard constraints on the dark energy equation of state, telescopes such as Phase I of the SKA should be able to obtain constrains about as well as a future galaxy redshift surveys. Statistical techniques to deal with foregrounds and calibration issues, as well as possible systematics are also discussed.
Measuring the clustering of photometric quasars through blind mitigation of systematics
Authors: Leistedt Boris , Peiris Hiranya V. , Roth Nina
Published: July 2015

We present accurate measurements of the large-scale clustering of photometric quasars from the Sloan Digital Sky Survey. These results, detailed in Leistedt & Peiris (2014), rely on a novel technique to identify and treat systematics when measuring angular power spectra, using null-tests and analytical marginalisation. This approach can be used to maximise the extraction of information from current and future galaxy or quasar surveys. For example, it enables to robustly constrain primordial non-Gaussianity (PNG), which modifies the bias of galaxies and quasars on large scales – the most sensitive to observational systematics. The constraints on PNG obtained with the quasar power spectra are detailed in Leistedt, Peiris & Roth (2014); these are the most stringent constraints to date obtained with a single tracer of the large-scale structure.
The effect of supranational identity on cultural values in Europe
Authors: Zapryanova Galina M. , Surzhko-Harned Lena
Published: July 2015

Does supranational identity have an independent effect on individuals’ beliefs about culturally contested issues in their national systems? This article demonstrates that self-categorization in the supranational realm – a seemingly unrelated category to domestic value cleavages – has implications for individuals’ views on cultural issues. Traditional theories of international norm diffusion focus almost exclusively on state-level interactions, but our findings provide further evidence to the existence of a more direct mechanism through which norms reach some citizens. A sense of identification with a supranational entity such as Europe makes citizens more likely to espouse the views and opinions promoted by supranational organizations. We use the European Values Study to examine whether supranational identity is associated with socially liberal preferences. Results from the multi-level models indicate that supranational identity exerts a systematic effect on attitudes toward lesbian, gay, bisexual, and transgender rights and gender equality. Additionally, while these effects are more consistent in EU member states, supranational identity exhibits a similar impact on social attitudes in non-EU countries such as those in the former Soviet Union.
A review of directional modulation technology
Authors: Ding Yuan , Fusco Vincent
Published: July 2015

Directional modulation (DM) is an emerging technology for securing wireless communications at the physical layer. This promising technology, unlike the conventional key-based cryptographic methods and the key-based physical layer security approaches, locks information signals without any requirements of keys. The locked information can only be fully recovered by the legitimate receiver(s) priory known by DM transmitters. This paper reviews the origin of the DM concept and, particularly, its development in recent years, including its mathematical model, assessment metrics, synthesis approaches, physical realizations, and finally its potential aspects for future studies.
Entwicklung und Validierung der Skalen zur motivationalen Regulation beim Lernen
Authors: Thomas Almut E. , Müller Florian H.
Published: July 2015

Zusammenfassung. Die vorliegende Studie diente der Entwicklung, psychometrischen Überprüfung und Validierung einer sprachlich vereinfachten Kurzversion der Skalen zur motivationalen Regulation beim Lernen von Schülerinnen und Schülern im Sinne der Selbstbestimmungstheorie der Motivation nach Deci und Ryan (1985) . Sowohl aus Gründen der Zeitökonomie als auch für jüngere Schülerinnen und Schüler und Jugendliche mit geringer Lesekompetenz ist die Verwendung von kurzen und besonders einfach formulierten Fragebögen vorteilhaft bzw. angebracht. Die psychometrischen Eigenschaften und die Validität des Fragebogens wurden mit einer Stichprobe von N = 2 854 Schülerinnen und Schülern der 4. Bis 8. Schulstufe in den Fächern Mathematik und Deutsch überprüft. Die psychometrischen Kennwerte der Skalen zur Motivationalen Regulation beim Lernen (SMR-L) sind durchwegs gut. Anhand konfirmatorischer Faktorenanalysen konnte gezeigt werden, dass die postulierte Struktur gut begründet ist, und die Skalen invariant hinsichtlich Schulfach, Geschlecht und Schulstufe sind. Die Korrelationen der SMR-L mit Noten, wahrgenommener Autonomieunterstützung, fachspezifischem Selbstkonzept, Emotionen im Unterricht sowie mit Anstrengungsbereitschaft und Ausdauer sind theoriekonform.
Seismic Hazard Assessment: Honing the Debate, Testing the Models
Authors: Stein Ross , Stirling Mark
Published: July 2015

Earthquake experts with opposing views found common ground working around a table and on a hiking trail.
Measuring Cerebrovascular Reactivity: The Dynamic Response to a Step Hypercapnic Stimulus
Authors: Poublanc Julien , Crawley Adrian P , Sobczyk Olivia , Montandon Gaspard , Sam Kevin , Mandell Daniel M , Dufort Paul , Venkatraghavan Lashmikumar , Duffin James , Mikulis David J , Fisher Joseph A
Published: July 2015

We define cerebral vascular reactivity (CVR) as the ratio of the change in blood oxygen level-dependent (BOLD) magnetic resonance imaging (MRI) signal (S) to an increase in blood partial pressure of CO2 (PCO2): % Δ S/Δ PCO2 mm Hg. Our aim was to further characterize CVR into dynamic and static components and then study 46 healthy subjects collated into a reference atlas and 20 patients with unilateral carotid artery stenosis. We applied an abrupt boxcar change in PCO2 and monitored S. We convolved the PCO2 with a set of first-order exponential functions whose time constant τ was increased in 2-second intervals between 2 and 100 seconds. The τ corresponding to the best fit between S and the convolved PCO2 was used to score the speed of response. Additionally, the slope of the regression between S and the convolved PCO2 represents the steady-state CVR (ssCVR). We found that both prolongations of τ and reductions in ssCVR (compared with the reference atlas) were associated with the reductions in CVR on the side of the lesion. τ and ssCVR are respectively the dynamic and static components of measured CVR.
Arteriole Dilation to Synaptic Activation that is Sub-Threshold to Astrocyte Endfoot Ca2+ Transients
Authors: Institoris Ádám , Rosenegger David George , Gordon Grant Robert
Published: July 2015

Ca2+-dependent pathways in neurons and astrocyte endfeet initiate changes in arteriole diameter to regulate local brain blood flow. Whether there exists a threshold of synaptic activity in which arteriole diameter is controlled independent of astrocyte endfeet Ca2+ remains unclear. We used two-photon fluorescence microscopy to examine synaptically evoked synthetic or genetic Ca2+ indicator signals around penetrating arterioles in acute slices of the rat neocortex. We discovered a threshold below which vasodilation occurred in the absence of endfeet Ca2+ signals but with consistent neuronal Ca2+ transients, suggesting endfoot Ca2+ is not necessary for activity-dependent vasodilation under subtle degrees of brain activation.
Multimodal Imaging Reveals Temporal and Spatial Microglia and Matrix Metalloproteinase Activity after Experimental Stroke
Authors: Zinnhardt Bastian , Viel Thomas , Wachsmuth Lydia , Vrachimis Alexis , Wagner Stefan , Breyholz Hans-Jörg , Faust Andreas , Hermann Sven , Kopka Klaus , Faber Cornelius , Dollé Frédéric , Pappata Sabina , Planas Anna M , Tavitian Bertrand , Schäfers Michael , Sorokin Lydia M , Kuhlmann Michael T , Jacobs Andreas H
Published: July 2015

Stroke is the most common cause of death and disability from neurologic disease in humans. Activation of microglia and matrix metalloproteinases (MMPs) is involved in positively and negatively affecting stroke outcome. Novel, noninvasive, multimodal imaging methods visualizing microglial and MMP alterations were employed. The spatio-temporal dynamics of these parameters were studied in relation to blood flow changes. Micro positron emission tomography (μPET) using [18F]BR-351 showed MMP activity within the first days after transient middle cerebral artery occlusion (tMCAo), followed by increased [18F]DPA-714 uptake as a marker for microglia activation with a maximum at 14 days after tMCAo. The inflammatory response was spatially located in the infarct core and in adjacent (penumbral) tissue. For the first time, multimodal imaging based on PET, single photon emission computed tomography, and magnetic resonance imaging revealed insight into the spatio-temporal distribution of critical parameters of poststroke inflammation. This allows further evaluation of novel treatment paradigms targeting the postischemic inflammation.
Tissue-Type Plasminogen Activator Triggers the Synaptic Vesicle Cycle in Cerebral Cortical Neurons
Authors: Wu Fang , Torre Enrique , Cuellar-Giraldo David , Cheng Lihong , Yi g , Bichler Edyta K , García Paul S , Yepes Manuel
Published: July 2015

The active zone (AZ) is a thickening of the presynaptic membrane where exocytosis takes place. Chemical synapses contain neurotransmitter-loaded synaptic vesicles (SVs) that at rest are tethered away from the synaptic release site, but after the presynaptic inflow of Ca+2 elicited by an action potential translocate to the AZ to release their neurotransmitter load. We report that tissue-type plasminogen activator (tPA) is stored outside the AZ of cerebral cortical neurons, either intermixed with small clear-core vesicles or in direct contact with the presynaptic membrane. We found that cerebral ischemia-induced release of neuronal tPA, or treatment with recombinant tPA, recruits the cytoskeletal protein βII-spectrin to the AZ and promotes the binding of SVs to βII-spectrin, enlarging the population of SVs in proximity to the synaptic release site. This effect does not require the generation of plasmin and is followed by the recruitment of voltage gated calcium channels (VGCC) to the presynaptic terminal that leads to Ca+2-dependent synapsin I phosphorylation, freeing SVs to translocate to the AZ to deliver their neurotransmitter load. Our studies indicate that tPA activates the SV cycle and induces the structural and functional changes in the synapse that are required for successful neurotransmission.
MicroRNA-29b is a Therapeutic Target in Cerebral Ischemia Associated with Aquaporin 4
Authors: Wang Yang , Huang Jun , Ma Yuanyuan , Tang Guanghui , Liu Yanqun , Chen Xiaoyan , Zhang Zhijun , Zeng Lili , Wang Yongting , Ouyang Yi-Bing , Yang Guo-Yuan
Published: July 2015

MicroRNA-29b (miR-29b) is involved in regulating ischemia process, but the molecular mechanism is unclear. In this work, we explored the function of miR-29b in cerebral ischemia. The level of miR-29b in white blood cells was evaluated in patients and mice after ischemic stroke. Brain infarct volume and National Institute of Health stroke scale (NIHSS) scores were analyzed to determine the relationship between miR-29b expression and the severity of stroke. The relationship of miR-29b and aquaporin-4 (AQP4) was further studied in mice. We found that miR-29b was significantly downregulated in stroke patients ( P < 0.05). MiR-29b level negatively associated with NIHSS scores ( r = −0.349, P < 0.01) and brain infarct volume ( r = −0.321, P < 0.05). In ischemic mice, miR-29b in the brain and blood were both downregulated ( r =0.723, P < 0.05). MiR-29b overexpression reduced infarct volume (49.50 ±6.55 versus 35.48 ±2.28 mm3, P < 0.05), edema (164±4% versus 108±4%, P < 0.05), and blood-brain barrier (BBB) disruption compared with controls (15 ±9% versus 7 ±3%, P < 0.05). Aquaporin-4 expression greatly decreased after miR-29b overexpression (28±7% versus 11 ±3%, P < 0.05). Dual-luciferase reporter system showed that AQP-4 was the direct target of miR-29b ( P < 0.05). We concluded that miR-29b could potentially predict stroke outcomes as a novel circulating biomarker, and miR-29b overexpression reduced BBB disruption after ischemic stroke via downregulating AQP-4.
Mixing of immiscible polymers using nanoporous coordination templates
Authors: Uemura Takashi , Kaseda Tetsuya , Sasaki Yotaro , Inukai Munehiro , Toriyama Takaaki , Takahara Atsushi , Jinnai Hiroshi , Kitagawa Susumu
Published: July 2015

The establishment of methodologies for the mixing of immiscible substances is highly desirable to facilitate the development of fundamental science and materials technology. Herein we describe a new protocol for the compatibilization of immiscible polymers at the molecular level using porous coordination polymers (PCPs) as removable templates. In this process, the typical immiscible polymer pair of polystyrene (PSt) and poly(methyl methacrylate) (PMMA) was prepared via the successive homopolymerizations of their monomers in a PCP to distribute the polymers inside the PCP particles. Subsequent dissolution of the PCP frameworks in a chelator solution affords a PSt/PMMA blend that is homogeneous in the range of several nanometers. Due to the unusual compatibilization, the thermal properties of the polymer blend are remarkably improved compared with the conventional solvent-cast blend. This method is also applicable to the compatibilization of PSt and polyacrylonitrile, which have very different solubility parameters.
Bivalent separation into univalents precedes age-related meiosis I errors in oocytes
Authors: Sakakibara Yogo , Hashimoto Shu , Nakaoka Yoshiharu , Kouznetsova Anna , Höög Christer , Kitajima Tomoya S.
Published: July 2015

The frequency of chromosome segregation errors during meiosis I (MI) in oocytes increases with age. The two-hit model suggests that errors are caused by the combination of a first hit that creates susceptible crossover configurations and a second hit comprising an age-related reduction in chromosome cohesion. This model predicts an age-related increase in univalents, but direct evidence of this phenomenon as a major cause of segregation errors has been lacking. Here, we provide the first live analysis of single chromosomes undergoing segregation errors during MI in the oocytes of naturally aged mice. Chromosome tracking reveals that 80% of the errors are preceded by bivalent separation into univalents. The set of the univalents is biased towards balanced and unbalanced predivision of sister chromatids during MI. Moreover, we find univalents predisposed to predivision in human oocytes. This study defines premature bivalent separation into univalents as the primary defect responsible for age-related aneuploidy.
Phased-array sources based on nonlinear metamaterial nanocavities
Authors: Wolf Omri , Campione Salvatore , Benz Alexander , Ravikumar Arvind P. , Liu Sheng , Luk Ting S. , Kadlec Emil A. , Shaner Eric A. , Klem John F. , Sinclair Michael B. , Brener Igal
Published: July 2015

Coherent superposition of light from subwavelength sources is an attractive prospect for the manipulation of the direction, shape and polarization of optical beams. This phenomenon constitutes the basis of phased arrays, commonly used at microwave and radio frequencies. Here we propose a new concept for phased-array sources at infrared frequencies based on metamaterial nanocavities coupled to a highly nonlinear semiconductor heterostructure. Optical pumping of the nanocavity induces a localized, phase-locked, nonlinear resonant polarization that acts as a source feed for a higher-order resonance of the nanocavity. Varying the nanocavity design enables the production of beams with arbitrary shape and polarization. As an example, we demonstrate two second harmonic phased-array sources that perform two optical functions at the second harmonic wavelength (∼5 μm): a beam splitter and a polarizing beam splitter. Proper design of the nanocavity and nonlinear heterostructure will enable such phased arrays to span most of the infrared spectrum.
Identification of malaria parasite-infected red blood cell surface aptamers by inertial microfluidic SELEX (I-SELEX)
Authors: Birch Christina M. , Hou Han Wei , Han Jongyoon , Niles Jacquin C.
Published: July 2015

Plasmodium falciparum malaria parasites invade and remodel human red blood cells (RBCs) by trafficking parasite-synthesized proteins to the RBC surface. While these proteins mediate interactions with host cells that contribute to disease pathogenesis, the infected RBC surface proteome remains poorly characterized. Here we use a novel strategy (I-SELEX) to discover high affinity aptamers that selectively recognize distinct epitopes uniquely present on parasite-infected RBCs. Based on inertial focusing in spiral microfluidic channels, I-SELEX enables stringent partitioning of cells (efficiency ≥ 106) from unbound oligonucleotides at high volume throughput (~2 × 106 cells min−1). Using an RBC model displaying a single, non-native antigen and live malaria parasite-infected RBCs as targets, we establish suitability of this strategy for de novo aptamer selections. We demonstrate recovery of a diverse set of aptamers that recognize distinct, surface-displayed epitopes on parasite-infected RBCs with nanomolar affinity, including an aptamer against the protein responsible for placental sequestration, var2CSA. These findings validate I-SELEX as a broadly applicable aptamer discovery platform that enables identification of new reagents for mapping the parasite-infected RBC surface proteome at higher molecular resolution to potentially contribute to malaria diagnostics, therapeutics and vaccine efforts.
The role of miR-100 in regulating apoptosis of breast cancer cells
Authors: Gong Yi , He Tianliang , Yang Lu , Yang Geng , Chen Yulei , Zhang Xiaobo
Published: July 2015

Breast cancer is a serious health problem worldwide. Inhibition of apoptosis plays a major role in breast cancer tumorigenesis. MicroRNAs (miRNAs) play crucial roles in the regulation of apoptosis. However, the regulation of breast cancer apoptosis by miRNAs has not been intensively investigated. To address this issue, the effect of miR-100 on the cell proliferation of different breast cancer cells was characterized in the present study. The results showed that miR-100 was significantly upregulated in SK-BR-3 cells compared with other human breast cancer cells (MCF7, MDA-MB-453, T47D, HCC1954 and SUM149). Silencing miR-100 expression with anti-miRNA-100 oligonucleotide (AMO-miR-100) initiated apoptosis of SK-BR-3 cells in vitro and in vivo. However, the overexpression of miR-100 led to the proliferation inhibition of the miR-100-downregulated breast cancer cells. Antagonism of miR-100 in SK-BR-3 cells increased the expression of MTMR3, a target gene of miR-100, which resulted in the activation of p27 and eventually led to G2/M cell-cycle arrest and apoptosis. The downregulation of miR-100 sensitized SK-BR-3 cells to chemotherapy. Therefore, our finding highlights a novel aspect of the miR-100-MTMR3-p27 pathway in the molecular etiology of breast cancer.
A simple methodological validation of the gas/particle fractionation of polycyclic aromatic hydrocarbons in ambient air
Authors: Kim Yong-Hyun , Kim Ki-Hyun
Published: July 2015

The analysis of polycyclic aromatic hydrocarbons (PAH) in ambient air requires the tedious experimental steps of both sampling and pretreatment (e.g., extraction or clean-up). To replace pre-existing conventional methods, a simple, rapid and novel technique was developed to measure gas-particle fractionation of PAH in ambient air based on ‘sorbent tube-thermal desorption-gas chromatograph-mass spectrometer (ST-TD-GC-MS)’. The separate collection and analysis of ambient PAHs were achieved independently by two serially connected STs. The basic quality assurance confirmed good linearity, precision and high sensitivity to eliminate the need for complicated pretreatment procedures with the detection limit (16 PAHs: 13.1 ± 7.04 pg). The analysis of real ambient PAH samples showed a clear fractionation between gas (two-three ringed PAHs) and particulate phases (five-six ringed PAHs). In contrast, for intermediate (four ringed) PAHs (fluoranthene, pyrene, benz[a]anthracene and chrysene), a highly systematic/gradual fractionation was established. It thus suggests a promising role of ST-TD-GC-MS as measurement system in acquiring a reliable database of airborne PAH.
The Inhibition of the Rayleigh-Taylor Instability by Rotation
Authors: Baldwin Kyle A. , Scase Matthew M. , Hill Richard J. A.
Published: July 2015

It is well-established that the Coriolis force that acts on fluid in a rotating system can act to stabilise otherwise unstable flows. Chandrasekhar considered theoretically the effect of the Coriolis force on the Rayleigh-Taylor instability, which occurs at the interface between a dense fluid lying on top of a lighter fluid under gravity, concluding that rotation alone could not stabilise this system indefinitely. Recent numerical work suggests that rotation may, nevertheless, slow the growth of the instability. Experimental verification of these results using standard techniques is problematic, owing to the practical difficulty in establishing the initial conditions. Here, we present a new experimental technique for studying the Rayleigh-Taylor instability under rotation that side-steps the problems encountered with standard techniques by using a strong magnetic field to destabilize an otherwise stable system. We find that rotation about an axis normal to the interface acts to retard the growth rate of the instability and stabilise long wavelength modes; the scale of the observed structures decreases with increasing rotation rate, asymptoting to a minimum wavelength controlled by viscosity. We present a critical rotation rate, dependent on Atwood number and the aspect ratio of the system, for stabilising the most unstable mode.
Signatures of positive selection in East African Shorthorn Zebu: A genome-wide single nucleotide polymorphism analysis
Authors: Bahbahani Hussain , Clifford Harry , Wragg David , Mbole-Kariuki Mary N , Van Tassell Curtis , Sonstegard Tad , Woolhouse Mark , Hanotte Olivier
Published: July 2015

The small East African Shorthorn Zebu (EASZ) is the main indigenous cattle across East Africa. A recent genome wide SNP analysis revealed an ancient stable African taurine x Asian zebu admixture. Here, we assess the presence of candidate signatures of positive selection in their genome, with the aim to provide qualitative insights about the corresponding selective pressures. Four hundred and twenty-five EASZ and four reference populations (Holstein-Friesian, Jersey, N’Dama and Nellore) were analysed using 46,171 SNPs covering all autosomes and the X chromosome. Following FST and two extended haplotype homozygosity-based (iHS and Rsb) analyses 24 candidate genome regions within 14 autosomes and the X chromosome were revealed, in which 18 and 4 were previously identified in tropical-adapted and commercial breeds, respectively. These regions overlap with 340 bovine QTL. They include 409 annotated genes, in which 37 were considered as candidates. These genes are involved in various biological pathways (e.g. immunity, reproduction, development and heat tolerance). Our results support that different selection pressures (e.g. environmental constraints, human selection, genome admixture constrains) have shaped the genome of EASZ. We argue that these candidate regions represent genome landmarks to be maintained in breeding programs aiming to improve sustainable livestock productivity in the tropics.
Functional BCL-2 regulatory genetic variants contribute to susceptibility of esophageal squamous cell carcinoma
Authors: Pan Wenting , Yang Jinyun , Wei Jinyu , Chen Hongwei , Ge Yunxia , Zhang Jingfeng , Wang Zhiqiong , Zhou Changchun , Yuan Qipeng , Zhou Liqing , Yang Ming
Published: July 2015

B-cell lymphoma-2 (BCL-2) prevents apoptosis and its overexpression could promote cancer cell survival. Multiple functional BCL-2 genetic polymorphisms, such as rs2279115, rs1801018 and rs1564483, have been identified previously and might be involved in cancer development through deregulating BCL-2 expression. Therefore, we examined associations between these three polymorphisms and esophageal squamous cell carcinoma (ESCC) susceptibility as well as its biological function in vivo. Genotypes were determined in two independent case-control sets consisted of 1588 ESCC patients and 1600 controls from two regions of China. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated by logistic regression. The impact of the rs2279115 polymorphism on BCL-2 expression was detected using esophagus tissues. Our results demonstrated that the BCL-2 rs2279115 AA genotype was significantly associated with decreased ESCC risk compared with the CC genotype (OR = 0.72, 95% CI = 0.57–0.90, P = 0.005), especially in nonsmokers (OR = 0.42, 95% CI = 0.29–0.59, P = 0.001) or nondrinkers (OR = 0.44, 95% CI = 0.32–0.62, P = 0.002). Genotype-phenotype correlation studies demonstrated that subjects with the rs2279115 CA and AA genotypes had a statistically significant decrease of BCL-2 mRNA expression compared to the CC genotype in both normal and cancerous esophagus tissues. Our results indicate that the BCL-2 rs2279115 polymorphism contributes to ESCC susceptibility in Chinese populations.
Folic acid supplements and colorectal cancer risk: meta-analysis of randomized controlled trials
Authors: Qin Tingting , Du Mulong , Du Haina , Shu Yongqian , Wang Meilin , Zhu Lingjun
Published: July 2015

Numerous studies have investigated the effects of folic acid supplementation on colorectal cancer risk, but conflicting results were reported. We herein performed a meta-analysis based on relevant studies to reach a more definitive conclusion. The PubMed and Embase databases were searched for quality randomized controlled trials (RCTs) published before October 2014. Eight articles met the inclusion criteria and were subsequently analyzed. The results suggested that folic acid treatment was not associated with colorectal cancer risk in the total population (relative risk [RR] = 1.00, 95% confidence interval [CI] = 0.82–1.22, P = 0.974). Moreover, no statistical effect was identified in further subgroup analyses stratified by ethnicity, gender, body mass index (BMI) and potential confounding factors. No significant heterogeneity or publication bias was observed. In conclusion, our meta-analysis demonstrated that folic acid supplementation had no effect on colorectal cancer risk. However, this finding must be validated by further large studies.
Collision cross section calibrants for negative ion mode traveling wave ion mobility-mass spectrometry
Authors: Forsythe Jay G. , Petrov Anton S. , Walker Chelsea A. , Allen Samuel J. , Pellissier Jarrod S. , Bush Matthew F. , Hud Nicholas V. , Fernández Facundo M.
Published: July 2015

Introduction of a novel negative mode calibrant and evaluation of calibration strategies for TWIM CCS determination.
A single fluorophore to address multiple logic gates
Authors: Sahu Saugata , Sil Timir Baran , Das Minati , Krishnamoorthy G.
Published: July 2015

Logic gates with different radixes have been constructed using a biologically active molecule, 2-(4′-N,N-dimethylaminophenyl)imidazo[4,5-b]pyridine (DMAPIP-b).
Screening and identification strategy for 317 pesticides in fruits and vegetables by liquid chromatography-quadrupole time-of-flight high resolution mass spectrometry
Authors: Wang Zhibin , Chang Qiaoying , Kang Jian , Cao Yanzhong , Ge Na , Fan Chunlin , Pang Guo-Fang
Published: July 2015

A screening and identification method was set up for routine qualitative detection of multi-pesticide residues in fruits and vegetables based on a home-made accurate database and spectral library.
The interplay of fibronectin functionalization and TGF-β1 presence on fibroblast proliferation, differentiation and migration in 3D matrices
Authors: Sapudom Jiranuwat , Rubner Stefan , Martin Steve , Thoenes Stephan , Anderegg Ulf , Pompe Tilo
Published: July 2015

TGF-β1 dependent fibroblast behaviour in a wound healing context is mimicked by topologically and mechanically defined collagen matrices with fibronectin functionalization.
Thermosetting resins with high fractions of free volume and inherently low dielectric constants
Authors: Lin Liang-Kai , Hu Chien-Chieh , Su Wen-Chiung , Liu Ying-Ling
Published: July 2015

A new class of thermosetting resins are developed through the ketene chemistry with in situ formation of cavities in the resins so as to reduce the dielectric constants of the resins to about 2.0.
Stabilization of cubic Sr2FeMoO6 through topochemical reduction
Authors: Taylor Daniel D. , Schreiber Nathaniel J. , Brown Craig M. , Arevalo-Lopez Angel M. , Rodriguez Efrain E.
Published: July 2015

Cubic Sr2FeMoO6 has been stabilized at room temperature, through topochemical de-intercalation of oxygen anions, whilst leaving magnetic ordering intact.
Highly efficient heterogeneous aerobic cross-dehydrogenative coupling via C–H functionalization of tertiary amines using a nanoporous gold skeleton catalyst
Authors: Ho Hon Eong , Ishikawa Yoshifumi , Asao Naoki , Yamamoto Yoshinori , Jin Tienan
Published: July 2015

We disclosed that zero-valent nanoporous gold (AuNPore) possesses remarkable catalytic activity and reusability for heterogeneous aerobic cross-dehydrogenative coupling (CDC) of various tertiary amines with nucleophiles.
Bioorthogonal labelling of living bacteria using unnatural amino acids containing nitrones and a nitrone derivative of vancomycin
Authors: MacKenzie Douglas A. , Sherratt Allison R. , Chigrinova Mariya , Kell Arnold J. , Pezacki John Paul
Published: July 2015

Unnaturald-amino acids bearing endocyclic nitrones were developed for live-cell labelling of the bacterial peptidoglycan layer.
Electroclinic effect in a chiral carbosilane-terminated 5-phenylpyrimidine liquid crystal with ‘de Vries-like’ properties
Authors: Schubert Christopher P. J. , Müller Carsten , Wand Michael D. , Giesselmann Frank , Lemieux Robert P.
Published: July 2015

The chiral carbosilane-terminated liquid crystal 2-[(2S,3S)-2,3-difluorohexyloxy]-5-[4-(12,12,14,14,16,16-hexamethyl-12,14,16-trisilaheptadecyloxy)phenyl]pyrimidine (QL32-6) undergoes a smectic A*-smectic C* phase transition with a maximum layer contraction of only 0.2%.
Combustion synthesis and excellent photocatalytic degradation properties of W18O49
Authors: Chen Pengqi , Qin Mingli , Zhang Dezhi , Chen Zheng , Jia Baorui , Wan Qi , Wu Haoyang , Qu Xuanhui
Published: July 2015

One-dimensional W18O49 nanoneedles were fabricated by solution combustion synthesis and exhibited an excellent visible light-driven photocatalytic performance.
Kinetics of the unimolecular reaction of CH2OO and the bimolecular reactions with the water monomer, acetaldehyde and acetone under atmospheric conditions
Authors: Berndt Torsten , Kaethner Ralf , Voigtländer Jens , Stratmann Frank , Pfeifle Mark , Reichle Patrick , Sipilä Mikko , Kulmala Markku , Olzmann Matthias
Published: July 2015

The rate coefficients of the unimolecular reaction of CH2OO and the bimolecular reactions with the water monomer and carbonyls were measured.
Fabrication of hierarchical ZnO/CdS heterostructured nanocomposites for enhanced hydrogen evolution from solar water splitting
Authors: Mukhopadhyay Soumita , Mondal Indranil , Pal Ujjwal , Devi Parukuttyamma Sujatha
Published: July 2015

The morphology of the host matrix ZnO helped in forming intimately mixed ZnO/CdS composites with enhanced hydrogen evolution efficiency and photostability.
The low frequency modes of solvated ions and ion pairs in aqueous electrolyte solutions: iron(ii) and iron(iii) chloride
Authors: Böhm Fabian , Sharma Vinay , Schwaab Gerhard , Havenith Martina
Published: July 2015

THz/FIR spectra of aqueous FeCl2and FeCl3solutions have been dissected into the contributions of different complex species, which were then used to identify the composition of unknown mixed solutions.
Optical imaging probes for biomolecules: an introductory perspective
Authors: Thomas Jim A.
Published: July 2015

An overview of optical biomolecular imaging is provided.