678 research outputs found
A triclinic polymorph of benzanilide : disordered molecules form hydrogen-bonded chains
Peer reviewedPublisher PD
Effects of the reaction cavity on metastable optical excitation in ruthenium-sulfur dioxide complexes
We report photoexcited-state crystal structures for two new members of the
[Ru(SO_2)(NH_3)_4X]Y family: 1:X=H2O, Y=(+/-)-camphorsulfonate_2;
2:X=isonicotinamide, Y=tosylate_2. The excited states are metastable at 100 K,
with a photoconversion fraction of 11.1(7)% achieved in 1, and 22.1(10)% and
26.9(10)% at the two distinct sites in 2.We further show using solid-state
density-functional-theory calculations that the excited-state geometries
achieved are strongly influenced by the local crystal environment. This result
is relevant to attempts to rationally design related photoexcitation systems
for optical data-storage applications.Comment: 6 pages, 5 figure
Dense genotyping of immune-related loci in idiopathic inflammatory myopathies confirms HLA alleles as the strongest genetic risk factor and suggests different genetic background for major clinical subgroups
OBJECTIVES: The idiopathic inflammatory myopathies (IIMs) are a heterogeneous group of rare autoimmune diseases characterised by muscle weakness and extramuscular manifestations such as skin rashes and interstitial lung disease. We genotyped 2566 IIM cases of Caucasian descent using the Immunochip; a custom array covering 186 established autoimmune susceptibility loci. The cohort was predominantly comprised of patients with dermatomyositis (DM, n=879), juvenile DM (JDM, n=481), polymyositis (PM, n=931) and inclusion body myositis (n=252) collected from 14 countries through the Myositis Genetics Consortium. RESULTS: The human leucocyte antigen (HLA) and PTPN22 regions reached genome-wide significance (
Sterile Neutrinos in E_6 and a Natural Understanding of Vacuum Oscillation Solution to the Solar Neutrino Puzzle
If Nature has chosen the vacuum oscillation solution to the Solar neutrino
puzzle, a key theoretical challenge is to understand the extreme smallness of
the () required for the purpose.
We find that in a class of models such as [SU(3)]^3 or its parent group E_6,
which contain one sterile neutrino, for each family, the is proportional to the cube of the lepton Yukawa
coupling. Therefore fitting the atmospheric neutrino data then predicts the
mass difference square to be , where the atmospheric neutrino data is assumed to be
solved via the oscillation. This provides a natural
explanation of the vacuum oscillation solution to the solar neutrino problem.Comment: 7 pages, UMD-PP-99-109; new references added; no other chang
Protein interactions in Xenopus germ plasm RNP particles
Hermes is an RNA-binding protein that we have previously reported to be found in the ribonucleoprotein (RNP) particles of Xenopus germ plasm, where it is associated with various RNAs, including that encoding the germ line determinant Nanos1. To further define the composition of these RNPs, we performed a screen for Hermes-binding partners using the yeast two-hybrid system. We have identified and validated four proteins that interact with Hermes in germ plasm: two isoforms of Xvelo1 (a homologue of zebrafish Bucky ball) and Rbm24b and Rbm42b, both RNA-binding proteins containing the RRM motif. GFP-Xvelo fusion proteins and their endogenous counterparts, identified with antisera, were found to localize with Hermes in the germ plasm particles of large oocytes and eggs. Only the larger Xvelo isoform was naturally found in the Balbiani body of previtellogenic oocytes. Bimolecular fluorescence complementation (BiFC) experiments confirmed that Hermes and the Xvelo variants interact in germ plasm, as do Rbm24b and 42b. Depletion of the shorter Xvelo variant with antisense oligonucleotides caused a decrease in the size of germ plasm aggregates and loosening of associated mitochondria from these structures. This suggests that the short Xvelo variant, or less likely its RNA, has a role in organizing and maintaining the integrity of germ plasm in Xenopus oocytes. While GFP fusion proteins for Rbm24b and 42b did not localize into germ plasm as specifically as Hermes or Xvelo, BiFC analysis indicated that both interact with Hermes in germ plasm RNPs. They are very stable in the face of RNA depletion, but additive effects of combinations of antisense oligos suggest they may have a role in germ plasm structure and may influence the ability of Hermes protein to effectively enter RNP particles
Material profiling for photocrystallography: Relating single-crystal photophysical and structural properties of luminescent bis- cyclometalated iridium-based complexes
Implications of mirror neutrinos for early universe cosmology
The Exact Parity Model (EPM) is, in part, a theory of neutrino mass and
mixing that can solve the atmospheric, solar and LSND anomalies. The central
feature of the neutrino sector is three pairs of maximally mixed ordinary and
mirror neutrinos. It has been shown that ordinary-mirror neutrino oscillations
can generate large neutrino asymmetries in the epoch of the early universe
immediately prior to Big Bang Nucleosynthesis (BBN). The large neutrino
asymmetries generically suppress the production of mirror neutrinos, and a
sufficiently large asymmetry can directly affect light element
synthesis through nuclear reaction rates. In this paper we present a detailed
calculation of neutrino asymmetry evolution driven by the six-flavour EPM
neutrino sector, focusing on implications for BBN.Comment: Latex, about 55 pages long with some figure
Novel role for the innate immune receptor toll-like receptor 4 (TLR4) in the regulation of the wnt signaling pathway and photoreceptor apoptosis
Recent evidence has implicated innate immunity in regulating neuronal survival in the brain during stroke and other neurodegenerations. Photoreceptors are specialized light-detecting neurons in the retina that are essential for vision. In this study, we investigated the role of the innate immunity receptor TLR4 in photoreceptors. TLR4 activation by lipopolysaccharide (LPS) significantly reduced the survival of cultured mouse photoreceptors exposed to oxidative stress. With respect to mechanism, TLR4 suppressed Wnt signaling, decreased phosphorylation and activation of the Wnt receptor LRP6, and blocked the protective effect of the Wnt3a ligand. Paradoxically, TLR4 activation prior to oxidative injury protected photoreceptors, in a phenomenon known as preconditioning. Expression of TNFα and its receptors TNFR1 and TNFR2 decreased during preconditioning, and preconditioning was mimicked by TNFα antagonists, but was independent of Wnt signaling. Therefore, TLR4 is a novel regulator of photoreceptor survival that acts through the Wnt and TNFα pathways. © 2012 Yi et al
The Impact of Railway Stations on Residential and Commercial Property Value: A Meta-analysis
Railway stations function as nodes in transport networks and places in an urban environment. They have accessibility and environmental impacts, which contribute to property value. The literature on the effects of railway stations on property value is mixed in its finding in respect to the impact magnitude and direction, ranging from a negative to an insignificant or a positive impact. This paper attempts to explain the variation in the findings by meta-analytical procedures. Generally the variations are attributed to the nature of data, particular spatial characteristics, temporal effects and methodology. Railway station proximity is addressed from two spatial considerations: a local station effect measuring the effect for properties with in 1/4 mile range and a global station effect measuring the effect of coming 250 m closer to the station. We find that the effect of railway stations on commercial property value mainly takes place at short distances. Commercial properties within 1/4 mile rang are 12.2% more expensive than residential properties. Where the price gap between the railway station zone and the rest is about 4.2% for the average residence, it is about 16.4% for the average commercial property. At longer distances the effect on residential property values dominate. We find that for every 250 m a residence is located closer to a station its price is 2.3% higher than commercial properties. Commuter railway stations have a consistently higher positive impact on the property value compared to light and heavy railway/Metro stations. The inclusion of other accessibility variables (such as highways) in the models reduces the level of reported railway station impact. © 2007 Springer Science+Business Media, LLC
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Catchment-scale biogeography of riverine bacterioplankton
Lotic ecosystems such as rivers and streams are unique in that they represent a continuum of both space and time during the transition from headwaters to the river mouth. As microbes have very different controls over their ecology, distribution and dispersion compared with macrobiota, we wished to explore biogeographical patterns within a river catchment and uncover the major drivers structuring bacterioplankton communities. Water samples collected across the River Thames Basin, UK, covering the transition from headwater tributaries to the lower reaches of the main river channel were characterised using 16S rRNA gene pyrosequencing. This approach revealed an ecological succession in the bacterial community composition along the river continuum, moving from a community dominated by Bacteroidetes in the headwaters to Actinobacteria-dominated downstream. Location of the sampling point in the river network (measured as the cumulative water channel distance upstream) was found to be the most predictive spatial feature; inferring that ecological processes pertaining to temporal community succession are of prime importance in driving the assemblages of riverine bacterioplankton communities. A decrease in bacterial activity rates and an increase in the abundance of low nucleic acid bacteria relative to high nucleic acid bacteria were found to correspond with these downstream changes in community structure, suggesting corresponding functional changes. Our findings show that bacterial communities across the Thames basin exhibit an ecological succession along the river continuum, and that this is primarily driven by water residence time rather than the physiochemical status of the river
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