374 research outputs found
Fundamental Investigations and Analysis of Chiral Matter Using Simple Spectroscopic Techniques
Fundamental investigations of circular dichroism were performed on (R)-(+)-3- methylcyclopentanone, (R)-(-)-2-butylamine, and (S)-(+)-2-butylamine in the liquid and vapor phase to show that solvents often have a structure-masking effect on the circular dichroism for a given molecule. Also, the solid state circular dichroism of cubic sodium chlorate crystals was successfully measured in the midst of adverse experimental circumstances. With these single photon circular dichroism studies at hand, a new technique for measuring circular dichroism was introduced for an advanced investigation of (R)-(+)-3-methylcyclopentanone. The resonance enhanced multiphoton ionization of (R)-(+)-3-methylcyclopentanone was performed with left and right circularly polarized laser light at a wavelength of 397.5 nm. This technique gave a dissymmetric factor g of 4.1 ± 0.23 x 10-2 in favor of the left circularly polarized light.
Parity violating energy difference studies were conducted on the enantiomers of alanine and valine. The conversion of one enantiomer to the other at 273 K was found not to occur due to temperature dependent studies of circular dichroism, x-ray diffraction, C-13 solid state NMR, Raman spectroscopy, magnetic susceptibility, differential scanning calorimetry, and theoretical calculations.
Highly intense 1064 nm pulsed laser light was used to induce crystallization in sodium chlorate, sodium bromate, and glycine aqueous solutions. The symmetry of sodium chlorate crystals and the asymmetry of sodium bromate crystals were broken by right circularly polarized and linearly polarized light, respectively. The g-polymorph of glycine was produced by an acidic pH change induced by the intense laser light. Under a Sr-90 source, 1,1’-binaphthyl crystallized into crystals showing a slight enantiomeric excess
Bounded Weak Solutions of Degenerate -Poisson Equations
In this work we study global boundedness and exponential integrability of
weak solutions to degenerate -Poisson equations using an iterative method of
De Giorgi type. Given a symmetric, non-negative definite matrix valued function
defined on a bounded domain , a weight function
, and a suitable non-negative function
, we give sufficient conditions for any weak solution to the Dirichlet
problem \begin{align*}
\begin{array}{rccl}
-\displaystyle\frac{1}{v}\mathrm{{div}}\left(\left|\sqrt{Q}\nabla
u\right|^{p-2}Q\nabla u\right)+\tau\left|u\right|^{p-2}u&=&f&\textrm{in
}\Omega,
\end{array} \end{align*} \begin{align*}
\begin{array}{rccl}
u&= & 0&\textrm{on }\partial\Omega
\end{array} \end{align*} to be bounded and exponentially integrable when the
data function belongs to an appropriate Orlicz space.Comment: Revised version includes several improved and condensed result
Families of Young Functions and Limits of Orlicz Norms
This paper provides conditions on a Young function and a one-parameter
family of Young functions that ensure the Orlicz norms associated
with each have the following property for any , The constant is independent of and depends only on the family
. Moreover, our conditions are necessary and sufficient if . Several examples of one-parameter families satisfying our
conditions are given, along with counterexamples when our conditions fails.
Applications in partial differential equations are also discussed
A Human Torque Teno Virus Encodes a MicroRNA That Inhibits Interferon Signaling
Rodney P. Kincaid, James M. Burke, Jennifer C. Cox, Christopher S. Sullivan, The University of Texas at Austin, Molecular Genetics and Microbiology, Austin, Texas, United States of AmericaEthel-Michele de Villiers, Division for the Characterization of Tumorviruses, Deutsches Krebsforschungszentrum, Heidelberg, GermanyTorque teno viruses (TTVs) are a group of viruses with small, circular DNA genomes. Members of this family are thought to ubiquitously infect humans, although causal disease associations are currently lacking. At present, there is no understanding of how infection with this diverse group of viruses is so prevalent. Using a combined computational and synthetic approach, we predict and identify miRNA-coding regions in diverse human TTVs and provide evidence for TTV miRNA production in vivo. The TTV miRNAs are transcribed by RNA polymerase II, processed by Drosha and Dicer, and are active in RISC. A TTV mutant defective for miRNA production replicates as well as wild type virus genome; demonstrating that the TTV miRNA is dispensable for genome replication in a cell culture model. We demonstrate that a recombinant TTV genome is capable of expressing an exogenous miRNA, indicating the potential utility of TTV as a small RNA vector. Gene expression profiling of host cells identifies N-myc (and STAT) interactor (NMI) as a target of a TTV miRNA. NMI transcripts are directly regulated through a binding site in the 3′UTR. SiRNA knockdown of NMI contributes to a decreased response to interferon signaling. Consistent with this, we show that a TTV miRNA mediates a decreased response to IFN and increased cellular proliferation in the presence of IFN. Thus, we add Annelloviridae to the growing list of virus families that encode miRNAs, and suggest that miRNA-mediated immune evasion can contribute to the pervasiveness associated with some of these viruses.This work was supported by grants RO1AI077746 from the National Institutes of Health, RP110098 from the Cancer Prevention and Research Institute of Texas, a Burroughs Wellcome Investigators in Pathogenesis Award to CSS, a UT Austin Powers Graduate Fellowship to RPK, a UT Austin Institute for Cellular and Molecular Biology fellowship, and the DKFZ for EMdV. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Molecular BiosciencesMicrobiologyEmail: [email protected]
Situational Judgment Tests: An Overview of Development Practices and Psychometric Characteristics
Situational judgment tests (SJTs) are popular assessment methods often used for personnel selection and promotion. SJTs present problem scenarios to examinees, who then evaluate each response option for addressing the issue described in the scenario. As guidance for practitioners and researchers alike, this paper provides experience- and evidence-based best practices for developing SJTs: writing scenarios and response options, creating response instructions, and selecting a response format. This review describes scoring options, including key stretching and within-person standardization. The authors also describe research on psychometric issues that affect SJTs, including reliability, validity, group differences, presentation modes, faking, and coaching
Watershed
The Chapter Introductions for the\ua0book\ua0The River: a history of Brisbane, published by the Museum of Brisbane in 2014 were part of the award-winning Exhibition of the same name. The Introductions provide condensed historical perspectives on the ways the Brisbane River winds its way through the city’s history. They are organised around six themes: Beauty, Watershed, Crossings, Within Reach, Shaping Forces and Embrace
Shaping forces
The Chapter Introductions for the\ua0book\ua0The River: a history of Brisbane, published by the Museum of Brisbane in 2014 were part of the award-winning Exhibition of the same name. The Introductions provide condensed historical perspectives on the ways the Brisbane River winds its way through the city’s history. They are organised around six themes: Beauty, Watershed, Crossings, Within Reach, Shaping Forces and Embrace
Increasing uptake to a lung cancer screening programme : Building with communities through co-design
Acknowledgements We would like to acknowledge the contribution of Dr Neil Arnott and all other organisations/individuals who helped engage participants. Funding This work was funded by the Chief Scientist Ofce (COBELT co-design study)Peer reviewedPublisher PD
Fine particle pH and the partitioning of nitric acid during winter in the northeastern United States
Particle pH is a critical but poorly constrained quantity that affects many aerosol processes and properties, including aerosol composition, concentrations, and toxicity. We assess PM1 pH as a function of geographical location and altitude, focusing on the northeastern U.S., based on aircraft measurements from the Wintertime Investigation of Transport, Emissions, and Reactivity campaign (1 February to 15 March 2015). Particle pH and water were predicted with the ISORROPIA-II thermodynamic model and validated by comparing predicted to observed partitioning of inorganic nitrate between the gas and particle phases. Good agreement was found for relative humidity (RH) above 40%; at lower RH observed particle nitrate was higher than predicted, possibly due to organic-inorganic phase separations or nitrate measurement uncertainties associated with low concentrations (nitrate \u3c 1 µg m−3). Including refractory ions in the pH calculations did not improve model predictions, suggesting they were externally mixed with PM1 sulfate, nitrate, and ammonium. Sample line volatilization artifacts were found to be minimal. Overall, particle pH for altitudes up to 5000 m ranged between −0.51 and 1.9 (10th and 90th percentiles) with a study mean of 0.77 ± 0.96, similar to those reported for the southeastern U.S. and eastern Mediterranean. This expansive aircraft data set is used to investigate causes in variability in pH and pH-dependent aerosol components, such as PM1 nitrate, over a wide range of temperatures (−21 to 19°C), RH (20 to 95%), inorganic gas, and particle concentrations and also provides further evidence that particles with low pH are ubiquitous
Characterizing the contaminating distance distribution for Bayesian supernova cosmology
Measurements of the equation of state of dark energy from surveys of
thousands of Type Ia Supernovae (SNe Ia) will be limited by spectroscopic
follow-up and must therefore rely on photometric identification, increasing the
chance that the sample is contaminated by Core Collapse Supernovae (CC SNe).
Bayesian methods for supernova cosmology can remove contamination bias while
maintaining high statistical precision but are sensitive to the choice of
parameterization of the contaminating distance distribution. We use simulations
to investigate the form of the contaminating distribution and its dependence on
the absolute magnitudes, light curve shapes, colors, extinction, and redshifts
of core collapse supernovae. We find that the CC luminosity function dominates
the distance distribution function, but its shape is increasingly distorted as
the redshift increases and more CC SNe fall below the survey magnitude limit.
The shapes and colors of the CC light curves generally shift the distance
distribution, and their effect on the CC distances is correlated. We compare
the simulated distances to the first year results of the SDSS-II SN survey and
find that the SDSS distance distributions can be reproduced with simulated CC
SNe that are ~1 mag fainter than the standard Richardson et al. (2002)
luminosity functions, which do not produce a good fit. To exploit the full
power of the Bayesian parameter estimation method, parameterization of the
contaminating distribution should be guided by the current knowledge of the CC
luminosity functions, coupled with the effects of the survey selection and
magnitude-limit, and allow for systematic shifts caused by the parameters of
the distance fit.Comment: 17 pages, 5 figures; accepted for publication in the Astrophysical
Journa
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