43 research outputs found
EXPERIMENTAL THERAPEUTICS Structure-Activity Relationship for Substance P Inhibition of Carbamylcholine-Stimulated 22Na Flux in Neuronal (PCi 2) and Non Neuronal (BC3H1 ) Cell Lines1
ABSTRAC
Identification and quantification of microplastics in wastewater using focal plane array-based reflectance micro-FT-IR imaging
Microplastics (<5 mm) have been documented in environmental samples on a global scale. While these pollutants may enter aquatic environments via wastewater treatment facilities, the abundance of microplastics in these matrices has not been investigated. Although efficient methods for the analysis of microplastics in sediment samples and marine organisms have been published, no methods have been developed for detecting these pollutants within organic-rich wastewater samples. In addition, there is no standardized method for analyzing microplastics isolated from environmental samples. In many cases, part of the identification protocol relies on visual selection before analysis, which is open to bias. In order to address this, a new method for the analysis of microplastics in wastewater was developed. A pretreatment step using 30% hydrogen peroxide (H2O2) was employed to remove biogenic material, and focal plane array (FPA)-based reflectance micro-Fourier-transform (FT-IR) imaging was shown to successfully image and identify different microplastic types (polyethylene, polypropylene, nylon-6, polyvinyl chloride, polystyrene). Microplastic-spiked wastewater samples were used to validate the methodology, resulting in a robust protocol which was nonselective and reproducible (the overall success identification rate was 98.33%). The use of FPA-based micro-FT-IR spectroscopy also provides a considerable reduction in analysis time compared with previous methods, since samples that could take several days to be mapped using a single-element detector can now be imaged in less than 9 h (circular filter with a diameter of 47 mm). This method for identifying and quantifying microplastics in wastewater is likely to provide an essential tool for further research into the pathways by which microplastics enter the environment.This work is funded by a NERC (Natural Environment Research Council) CASE studentship (NE/K007521/1) with contribution from industrial partner Fera Science Ltd., United Kingdom. The authors would like to thank Peter Vale, from Severn Trent Water Ltd, for providing access to and additionally Ashley Howkins (Brunel University London) for providing travel and assistance with the sampling of the Severn Trent wastewater treatment plant in Derbyshire, UK. We are grateful to Emma Bradley and Chris Sinclair for providing helpful suggestions for our research
Effect of heating rate on recrystallization of twin roll cast aluminum
Metallurgical and Materials Transactions a-Physical Metallurgy and Materials Science, 39A(1): pp. 165-170.The effect of heating rate on precipitation and recrystallization behavior in twin roll cast (TRC)
AA3105 has been investigated by three different means: conventional air furnace, controlled
infrared, and lead bath heating. Experimental results showed that as-recrystallized grain size
decreased and became more equiaxed as the annealing heating rate increased. These results were
explained via time-temperature-transformation (TTT) curves for both dispersoid precipitation
and recrystallization. With the faster heating rate, recrystallization could occur before precipitation
of Mn present in the unhomogenized TRC samples. At a heating rate of 50 degree C/s the
material underwent grain growth after recrystallization at 500 degree C. No sign of grain growth was
observed in materials annealed with lower heating rates, 3 degrees C/s, 0.5 degree C/s, and 0.01 degree C/s due to
greater dispersoid precipitation
Magnetic field-induced non-trivial electronic topology in Fe3âxGeTe2
The anomalous Hall, Nernst and thermal Hall coefficients of
FeGeTe display several features upon cooling, like a reversal in
the Nernst signal below K pointing to a topological transition (TT)
associated to the development of magnetic spin textures. Since the anomalous
transport variables are related to the Berry curvature, a possible TT might
imply deviations from the Wiedemann-Franz (WF) law. However, the anomalous Hall
and thermal Hall coefficients of FeGeTe are found, within our
experimental accuracy, to satisfy the WF law for magnetic-fields
applied along its inter-layer direction. Surprisingly, large anomalous
transport coefficients are also observed for applied along the planar
\emph{a}-axis as well as along the gradient of the chemical potential, a
configuration that should not lead to their observation due to the absence of
Lorentz force. However, as \emph{a}-axis is increased,
magnetization and neutron scattering indicate just the progressive canting of
the magnetic moments towards the planes followed by their saturation. These
anomalous planar quantities are found to not scale with the component of the
planar magnetization (), showing instead a sharp decrease beyond 4 T which is the field required to align the magnetic moments
along . We argue that locally chiral spin structures, such as
skyrmions, and possibly skyrmion tubes, lead to a field dependent
spin-chirality and hence to a novel type of topological anomalous transport.
Locally chiral spin-structures are captured by our Monte-Carlo simulations
incorporating small Dzyaloshinskii-Moriya and biquadratic exchange
interactions.Comment: 34 pages, 10 figures, submitted to Applied Physics Review
Improving the sensitivity to gravitational-wave sources by modifying the input-output optics of advanced interferometers
We study frequency dependent (FD) input-output schemes for signal-recycling
interferometers, the baseline design of Advanced LIGO and the current
configuration of GEO 600. Complementary to a recent proposal by Harms et al. to
use FD input squeezing and ordinary homodyne detection, we explore a scheme
which uses ordinary squeezed vacuum, but FD readout. Both schemes, which are
sub-optimal among all possible input-output schemes, provide a global noise
suppression by the power squeeze factor, while being realizable by using
detuned Fabry-Perot cavities as input/output filters. At high frequencies, the
two schemes are shown to be equivalent, while at low frequencies our scheme
gives better performance than that of Harms et al., and is nearly fully
optimal. We then study the sensitivity improvement achievable by these schemes
in Advanced LIGO era (with 30-m filter cavities and current estimates of
filter-mirror losses and thermal noise), for neutron star binary inspirals, and
for narrowband GW sources such as low-mass X-ray binaries and known radio
pulsars. Optical losses are shown to be a major obstacle for the actual
implementation of these techniques in Advanced LIGO. On time scales of
third-generation interferometers, like EURO/LIGO-III (~2012), with
kilometer-scale filter cavities, a signal-recycling interferometer with the FD
readout scheme explored in this paper can have performances comparable to
existing proposals. [abridged]Comment: Figs. 9 and 12 corrected; Appendix added for narrowband data analysi
Upper limits on the strength of periodic gravitational waves from PSR J1939+2134
The first science run of the LIGO and GEO gravitational wave detectors
presented the opportunity to test methods of searching for gravitational waves
from known pulsars. Here we present new direct upper limits on the strength of
waves from the pulsar PSR J1939+2134 using two independent analysis methods,
one in the frequency domain using frequentist statistics and one in the time
domain using Bayesian inference. Both methods show that the strain amplitude at
Earth from this pulsar is less than a few times .Comment: 7 pages, 1 figure, to appear in the Proceedings of the 5th Edoardo
Amaldi Conference on Gravitational Waves, Tirrenia, Pisa, Italy, 6-11 July
200
Search for gravitational wave bursts in LIGO's third science run
We report on a search for gravitational wave bursts in data from the three
LIGO interferometric detectors during their third science run. The search
targets subsecond bursts in the frequency range 100-1100 Hz for which no
waveform model is assumed, and has a sensitivity in terms of the
root-sum-square (rss) strain amplitude of hrss ~ 10^{-20} / sqrt(Hz). No
gravitational wave signals were detected in the 8 days of analyzed data.Comment: 12 pages, 6 figures. Amaldi-6 conference proceedings to be published
in Classical and Quantum Gravit
Peptide-Pulsed Dendritic Cells Induce the Hepatitis C Viral Epitope-Specific Responses of NaĂŻve Human T Cells
Hepatitis C virus (HCV) is a major cause of liver disease. Spontaneous resolution of infection is associated with broad, MHC class I- (CD8+) and class II-restricted (CD4+) T cell responses to multiple viral epitopes. Only 20% of patients clear infection spontaneously, however, most develop chronic disease. The response to chemotherapy varies; therapeutic vaccination offers an additional treatment strategy. To date, therapeutic vaccines have demonstrated only limited success in clinical trials. Vector-mediated vaccination with multi-epitope-expressing DNA constructs provides an improved approach. Highly-conserved, HLA-A2-restricted HCV epitopes and HLA-DRB1-restricted immunogenic consensus sequences (ICS, each composed of multiple overlapping and highly conserved epitopes) were predicted using bioinformatics tools and synthesized as peptides. HLA binding activity was determined in competitive binding assays. Immunogenicity and the ability of each peptide to stimulate naĂŻve human T cell recognition and IFN-Îł production were assessed in cultures of total PBMCs and in co-cultures composed of peptide-pulsed dendritic cells (DCs) and purified T lymphocytes, cell populations derived from normal blood donors. Essentially all predicted HLA-A2-restricted epitopes and HLA-DRB1-restricted ICS exhibited HLA binding activity and the ability to elicit immune recognition and IFN-Îł production by naĂŻve human T cells. The ability of DCs pulsed with these highly-conserved HLA-A2- and -DRB1-restricted peptides to induce naĂŻve human T cell reactivity and IFN-Îł production ex vivo demonstrates the potential efficacy of a multi-epitope-based HCV vaccine targeted to dendritic cells
Significant uncertainty in global scale hydrological modeling from precipitation data errors
Two Domains of the Beta Subunit of Neuronal Nicotinic Acetylcholine Receptors Contribute to the Affinity of Substance P 1
ABSTRACT Substance P is known to noncompetitively inhibit activation of muscle and neuronal nicotinic acetylcholine receptors. Neuronal nicotinic receptors formed from different combinations of ⣠and †subunits exhibited differential sensitivity to substance P, with those containing â€-4 subunits having a 25-fold higher affinity than those having â€-2 subunits. To identify the regions and/or amino acid residues of the †subunit responsible for this difference, chimeric †subunits were coexpressed with âŁ-3 in Xenopus oocytes and the IC 50 values for substance P were determined. Amino acid residues between 105 and 109 (â€4 numbering), in the middle of the N-terminal domain, and between 214 and 301, between the extracellular side of M1 and the intracellular side of M3, were identified as major contributors to the apparent affinity of substance P. The affinity of acetylcholine was only affected by residue changes between 105 and 109. Site-directed mutagenesis revealed two amino acids that are important determinants of the affinity of substance P, â€4(V108)/â€2(F106), which is in the middle of the first extracellular domain, and â€4(F255)/â€2(V253), which is within the putative channel lining transmembrane domain M2. However, other residues within these domains must be making subtle but significant contributions, since simultaneous mutation of both these amino acids did not cause complete interconversion of the †subunit-dependent differences in the receptor affinity for substance P. The tachykinin SP is a neurotransmitter and neuromodulator in the central and peripheral nervous systems Muscle and neuronal nAChRs are pentameric proteins forming ligand-gated ion channel