8,963 research outputs found
Mouse ribonuclease III. cDNA structure, expression analysis, and chromosomal location
BACKGROUND: Members of the ribonuclease III superfamily of double-stranded(ds)-RNA-specific endoribonucleases participate in diverse RNA maturation and decay pathways in eukaryotic and prokaryotic cells. A human RNase III orthologue has been implicated in ribosomal RNA maturation. To better understand the structure and mechanism of mammalian RNase III and its involvement in RNA metabolism we determined the cDNA structure, chromosomal location, and expression patterns of mouse RNase III. RESULTS: The predicted mouse RNase III polypeptide contains 1373 amino acids (~160 kDa). The polypeptide exhibits a single C-terminal dsRNA-binding motif (dsRBM), tandem catalytic domains, a proline-rich region (PRR) and an RS domain. Northern analysis and RT-PCR reveal that the transcript (4487 nt) is expressed in all tissues examined, including extraembryonic tissues and the midgestation embryo. Northern analysis indicates the presence of an additional, shorter form of the transcript in testicular tissue. Fluorescent in situ hybridization demonstrates that the mouse RNase III gene maps to chromosome 15, region B, and that the human RNase III gene maps to a syntenic location on chromosome 5p13-p14. CONCLUSIONS: The broad transcript expression pattern indicates a conserved cellular role(s) for mouse RNase III. The putative polypeptide is highly similar to human RNase III (99% amino acid sequence identity for the two catalytic domains and dsRBM), but is distinct from other eukaryotic orthologues, including Dicer, which is involved in RNA interference. The mouse RNase III gene has a chromosomal location distinct from the Dicer gene
Radiation effects on silver and zinc battery electrodes, III Interim report, Oct. 1965 - Jan. 1966
Radiation effects on silver-zinc battery electrode
Chaotic saddles in nonlinear modulational interactions in a plasma
A nonlinear model of modulational processes in the subsonic regime involving
a linearly unstable wave and two linearly damped waves with different damping
rates in a plasma is studied numerically. We compute the maximum Lyapunov
exponent as a function of the damping rates in a two-parameter space, and
identify shrimp-shaped self-similar structures in the parameter space. By
varying the damping rate of the low-frequency wave, we construct bifurcation
diagrams and focus on a saddle-node bifurcation and an interior crisis
associated with a periodic window. We detect chaotic saddles and their stable
and unstable manifolds, and demonstrate how the connection between two chaotic
saddles via coupling unstable periodic orbits can result in a crisis-induced
intermittency. The relevance of this work for the understanding of modulational
processes observed in plasmas and fluids is discussed.Comment: Physics of Plasmas, in pres
Fluoride release and uptake in enhanced bioactivity glass ionomer cement (“glass carbomer™”) compared with conventional and resin-modified glass ionomer cements
Objectives: To study the fluoride uptake and release properties of glass carbomer dental cements and compare them with those of conventional and resin-modified glass ionomers. Materials and Methods: Three materials were used, as follows: glass carbomer (Glass Fill), conventional glass ionomer (Chemfil Rock) and resin-modified glass ionomer (Fuji II LC). For all materials, specimens (sets of six) were matured at room temperature for time intervals of 10 minutes, 1 hour and 6 weeks, then exposed to either deionized water or sodium fluoride solution (1000 ppm in fluoride) for 24 hours. Following this, all specimens were placed in deionized water for additional 24 hours and fluoride release was measured. Results: Storage in water led to increase in mass in all cases due to water uptake, with uptake varying with maturing time and material type. Storage in aqueous NaF led to variable results. Glass carbomer showed mass losses at all maturing times, whereas the conventional glass ionomer gained mass for some maturing times, and the resin-modified glass ionomer gained mass for all maturing times. All materials released fluoride into deionized water, with glass carbomer showing the highest release. For both types of glass ionomer, uptake of fluoride led to enhanced fluoride release into deionized water. In contrast, uptake by glass carbomer did not lead to increased fluoride release, although it was substantially higher than the uptake by both types of glass ionomer. Conclusions: Glass carbomer resembles glass ionomer cements in its fluoride uptake behavior but differs when considering that its fluoride uptake does not lead to increased fluoride release
Revealing the role of electrons and phonons in the ultrafast recovery of charge density wave correlations in 1-TiSe
Using time- and angle-resolved photoemission spectroscopy with selective
near- and mid-infrared photon excitations, we investigate the femtosecond
dynamics of the charge density wave (CDW) phase in 1-TiSe, as well as
the dynamics of CDW fluctuations at 240 K. In the CDW phase, we observe the
coherent oscillation of the CDW amplitude mode. At 240 K, we single out an
ultrafast component in the recovery of the CDW correlations, which we explain
as the manifestation of electron-hole correlations. Our momentum-resolved study
of femtosecond electron dynamics supports a mechanism for the CDW phase
resulting from the cooperation between the interband Coulomb interaction, the
mechanism of excitonic insulator phase formation, and electron-phonon coupling.Comment: 9 pages, 6 figure
Public preferences for using quantitative faecal immunochemical test (FIT) vs colonoscopy (CC) as diagnostic test for colorectal cancer: Evidence from an online survey
Background: There has been interest in using the non-invasive, home-based quantitative faecal
immunochemical test (FIT) to rule out colorectal cancer (CRC) in high-risk symptomatic patients.
Aim: To elicit public preferences for FIT versus colonoscopy (CC) and its delivery in primary care.
Design & setting: A cross-sectional online survey in England.
Method: A total of 1057 adults (without CRC symptoms and diagnosis) aged 40–59 years were invited
from an English online survey panel. Responders were asked to imagine they had been experiencing
CRC symptoms that would qualify them for a diagnostic test. Participants were presented with choices
between CC and FIT in ascending order of number of CRCs missed by FIT (from 1–10%). It was
measured at what number of missed CRCs responders preferred CC over FIT.
Results: While 150 participants did not want either of the tests when both missed 1% CRCs, the
majority (n = 741, 70.0%) preferred FIT to CC at that level of accuracy. However, this preference
reduced to 427 (40.4%) when FIT missed one additional cancer. Women were more likely to tolerate
missing CRC when using FIT. Having lower numeracy and perceiving a higher level of risk meant
participants were less likely to tolerate a false negative test. Most of those who chose FIT preferred
to return it by mail (62.2%), to be informed about normal test results by letter (42.1%), and about
abnormal test results face to face (32.5%).
Conclusion: While the majority of participants preferred FIT over CC when both tests had the same
sensitivity, tolerance for missed CRCs was low
Democratization in a passive dendritic tree : an analytical investigation
One way to achieve amplification of distal synaptic inputs on a dendritic tree is to scale the amplitude and/or duration of the synaptic conductance with its distance from the soma. This is an example of what is often referred to as “dendritic democracy”. Although well studied experimentally, to date this phenomenon has not been thoroughly explored from a mathematical perspective. In this paper we adopt a passive model of a dendritic tree with distributed excitatory synaptic conductances and analyze a number of key measures of democracy. In particular, via moment methods we derive laws for the transport, from synapse to soma, of strength, characteristic time, and dispersion. These laws lead immediately to synaptic scalings that overcome attenuation with distance. We follow this with a Neumann approximation of Green’s representation that readily produces the synaptic scaling that democratizes the peak somatic voltage response. Results are obtained for both idealized geometries and for the more realistic geometry of a rat CA1 pyramidal cell. For each measure of democratization we produce and contrast the synaptic scaling associated with treating the synapse as either a conductance change or a current injection. We find that our respective scalings agree up to a critical distance from the soma and we reveal how this critical distance decreases with decreasing branch radius
ATS-6 spacecraft: In-flight antenna pattern measurement
Antenna patterns, principally associated with the 9.1 meter parabolic antenna of the ATS-6 spacecraft, were measured while in orbit at quasi-stationary synchronous altitude. Controlling the spacecraft attitude permitted a scanning of the spacecraft antenna pattern over the Rosman ground station, thus achieving the measurement of the antenna pattern contour. Patterns were determined in terms of relative gain referenced in position to the spacecraft body coordinates by means of signal power measurements made using a linear detector. These data were subsequently correlated with the attitude data to define the antenna patterns. Antenna patterns measured are presented and compared with available preflight patterns
- …