Previous simulations of the growth of cosmic structures have broadly reproduced the 'cosmic web' of galaxies that we see in the Universe, but failed to create a mixed population of elliptical and ...spiral galaxies, because of numerical inaccuracies and incomplete physical models. Moreover, they were unable to track the small-scale evolution of gas and stars to the present epoch within a representative portion of the Universe. Here we report a simulation that starts 12 million years after the Big Bang, and traces 13 billion years of cosmic evolution with 12 billion resolution elements in a cube of 106.5 megaparsecs a side. It yields a reasonable population of ellipticals and spirals, reproduces the observed distribution of galaxies in clusters and characteristics of hydrogen on large scales, and at the same time matches the 'metal' and hydrogen content of galaxies on small scales.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
This review discusses the integration of liquid chromatography (LC), mass spectrometry (MS), and nuclear magnetic resonance (NMR) in the comprehensive analysis of small molecules from complex ...matrices. We first discuss the steps taken toward making the three technologies compatible, so as to create an efficient analytical platform. The development of online LC‐MS‐NMR, highlighted by successful applications in the profiling of highly concentrated analytes (LODs 10 μg) is discussed next. This is followed by a detailed overview of the alternative approaches that have been developed to overcome the challenges associated with online LC‐MS‐NMR that primarily stem from the inherently low sensitivity of NMR. These alternative approaches include the use of stop‐flow LC‐MS‐NMR, loop collection of LC peaks, LC‐MS‐SPE‐NMR, and offline NMR. The potential and limitations of all these approaches is discussed in the context of applications in various fields, including metabolomics and natural product discovery.
Partially reflecting surfaces (PRS) with positive reflection phase gradients are investigated for the design of wideband, low-profile electromagnetic band gap (EBG) resonator antennas. Thin ...single-dielectric-slab PRSs with printed patterns on both sides are proposed to minimize the PRS thickness and to simplify fabrication. Three such surfaces, each with printed dipoles on both sides, have been designed to obtain different positive reflection phase gradients and reflection magnitude levels in the operating frequency bands. These surfaces, and the EBG resonator antennas formed from them, are analyzed theoretically and experimentally to highlight the design compromises involved and to reveal the relationships between the antenna peak gain, gain bandwidth, the reflection profile (i.e., positive phase gradient and magnitude) of the surface and the relative dimensions of dipoles. A small feed antenna, designed to operate in the cavity field environment, provides good impedance matching (|S 11 | <; -10 dB) across the operating frequency bands of all three EBG resonator antennas. Experimental results confirm the wideband performance of a simple, low-profile EBG resonator antenna. Its PRS thickness is only 1.6 mm, effective bandwidth is 12.6%, measured peak gain is 16.2 dBi at 11.5 GHz and 3 dB gain bandwidth is 15.7%.
The interleukins of fish Secombes, C.J.; Wang, T.; Bird, S.
Developmental and comparative immunology,
12/2011, Letnik:
35, Številka:
12
Journal Article
Recenzirano
Interleukins are a subgroup of cytokines, molecules involved in the intercellular regulation of the immune system. The term interleukin was first coined in 1979 to refer to molecules that signal ...between different leucocyte types, although not exclusively restricted to leucocyte communication. Whilst it is now known that interleukins are produced by a wide variety of cell types, nevertheless many are synthesised by CD4
+ T helper cells, macrophages/monocytes and endothelial cells. The nomenclature is relatively straightforward, with interleukin 1 the first discovered and interleukin 2 the second, etc. However, whilst 35 interleukins are currently described in mammals, several are in fact terms referring to subfamilies of more molecules, as with the IL-1 family where 11 members (IL-1F1–IL-1F11) are present, and the IL-17 family where 6 members (IL-17A–IL-17F) are present. So the total is much higher and splice variants and allelic variation increase this diversity further. This review will focus on what is known about interleukins in fish, and will refer to the major subfamilies rather than try to work through 35 descriptions in a row. It is clear that many direct homologues of molecules known in mammals are present in fish, but that not all are present and some novel interleukins exist that may have arisen from fish specific gene duplication events.
An unusually deep (V,I) imaging dataset for the Virgo supergiant M 87 with the Hubble Space Telescope ACS successfully resolves its brightest red-giant stars, reaching MI(lim) = −2.5. After assessing ...the photometric completeness and biasses, we use this material to estimate the metallicity distribution for the inner halo of M 87, finding that the distribution is very broad and likely to peak near m/H ≃ −0.4 and perhaps higher. The shape of the MDF strongly resembles that of the inner halo for the nearby giant E galaxy NGC 5128. As a byproduct of our study, we also obtain a preliminary measurement of the distance to M 87 with the TRGB (red-giant branch tip) method; the result is (m − M)0 = 31.12±0.14 (d = 16.7±0.9 Mpc). Averaging this result with three other recent techniques give a weighted mean d(M87) = (16.4 ± 0.5) Mpc.
The functions of store-operated calcium channels Putney, James W.; Steinckwich-Besançon, Natacha; Numaga-Tomita, Takuro ...
Biochimica et biophysica acta. Molecular cell research,
06/2017, Letnik:
1864, Številka:
6
Journal Article
Recenzirano
Odprti dostop
Store-operated calcium channels provide calcium signals to the cytoplasm of a wide variety of cell types. The basic components of this signaling mechanism include a mechanism for discharging Ca2+ ...stores (commonly but not exclusively phospholipase C and inositol 1,4,5-trisphosphate), a sensor in the endoplasmic reticulum that also serves as an activator of the plasma membrane channel (STIM1 and STIM2), and the store-operated channel (Orai1, 2 or 3). The advent of mice genetically altered to reduce store-operated calcium entry globally or in specific cell types has provided important tools to understand the functions of these widely encountered channels in specific and clinically important physiological systems. This review briefly discusses the history and cellular properties of store-operated calcium channels, and summarizes selected studies of their physiological functions in specific physiological or pathological contexts. This article is part of a Special Issue entitled: ECS Meeting edited by Claus Heizmann, Joachim Krebs and Jacques Haiech.
•Store-operated calcium entry is a calcium entry mechanism activated when endoplasmic reticulum calcium stores are reduced.•The players in store-operated calcium entry are the calcium sensors, STIM1 and 2, and the channel proteins, Orai1, 2 and 3.•Use of genetically modified mice has revealed multiple physiological roles for store-operated channels.
The incidence of asthma has been positively associated with obesity. Asthma comprises diverse "phenotypes" reflecting heterogeneity in a number of characteristics, including response to therapy. The ...present authors examined whether body mass index (BMI) influenced the response to placebo, as well as to two asthma controller medications. A post hoc analysis was performed, pooling data from four double-blind, placebo-controlled studies randomising 3,073 moderate asthmatic adults to montelukast (n=1,439), beclomethasone (n=894) or placebo (n=740). The primary end point was asthma control days; other end points were forced expiratory volume in one second, beta-agonist use and nocturnal awakening. Analyses were conducted using BMI classification into normal (<25.0 kg.m-2; 52% of patients), overweight (25-29.9 kg.m-2; 32%) and obese (>or=30.0 kg.m-2; 16%) categories, as well as BMI as a continuous variable. The treatment groups were balanced for BMI, demographic characteristics and parameters of asthma control. The placebo response for all end points was generally lower with increasing BMI. Similarly, the response to the inhaled corticosteroid decreased, whereas the response to the leukotriene antagonist remained stable. In conclusion, post hoc data from the present study suggested that body mass index may influence the natural history of asthma control (as reflected by response to placebo) and may differentially influence response to the two active agents, warranting explicit testing in future prospective studies.
Calcium oscillations Dupont, Geneviève; Combettes, Laurent; Bird, Gary S ...
Cold Spring Harbor perspectives in biology,
03/2011, Letnik:
3, Številka:
3
Journal Article
Recenzirano
Odprti dostop
Calcium signaling results from a complex interplay between activation and inactivation of intracellular and extracellular calcium permeable channels. This complexity is obvious from the pattern of ...calcium signals observed with modest, physiological concentrations of calcium-mobilizing agonists, which typically present as sequential regenerative discharges of stored calcium, a process referred to as calcium oscillations. In this review, we discuss recent advances in understanding the underlying mechanism of calcium oscillations through the power of mathematical modeling. We also summarize recent findings on the role of calcium entry through store-operated channels in sustaining calcium oscillations and in the mechanism by which calcium oscillations couple to downstream effectors.
Written by one of the world’s leading experts in the field, this book is intended as an advanced text for courses in antennas, with a focus on the mature but vital background field of aperture ...antennas. It is aimed at final year, MSc, PhD and post-doctoral students, as well as readers who are moving from academia into industry, beginning careers as wireless engineers, system designers, in R&D, or for practising engineers.
It assumes the reader has undertaken an earlier course of study on Maxwell’s equations, fields and waves. Some of these topics are summarized in the early few chapters in order to provide continuity and background for the remaining chapters. The aperture antennas covered include the main types of horns, reflectors and arrays as well as microstrip patches, reflectarrays and lenses. To provide more than a superficial treatment of arrays, the topic of mutual coupling is covered in greater detail compared to most similar books in this area. Also included is an introduction to arrays on non-planar surfaces, which are important in applications that involve curved surfaces such as in aerodynamics or for making aperture antennas unobtrusive. A chapter is included on some modern aperture antennas to illustrate design techniques beyond the most common types of aperture antennas described in the early chapters. This is to show where advances have recently been made and where they could be improved in the future. Also included are selective topics that are practical in nature for aperture antennas, namely fabrication and measurement.
A frequency reconfigurable printed Yagi-Uda antenna is presented for cognitive radio applications. A 46% continuous frequency tuning bandwidth is obtained by loading the driver dipole arms and four ...directors with varactor diodes. This configuration allows a high-gain and an almost constant end-fire pattern to be maintained while the antenna operating frequency is tuned. A parametric study was undertaken considering the inter-director spacing, director length tapering, and reflector geometry. It was found possible over the band that the front-to-back ratio is >; 16 dB, the sidelobe level is <; -14 dB and the cross polarization levels in the principal planes are <; - 15.5 dB. From 1-dB compression point measurements, the maximum input power of the antenna with the present diodes is limited to 17.6 dBm at 700 MHz. This suggests that reconfigurable antennas which use active components should have an IIP3 specification placed on them. The frequency selective feature of the antenna makes it as an attractive user terminal antenna for fixed point-to-multipoint cognitive radio enabled broadband wireless access.
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