3,106 research outputs found
(4S,5S)-2,2-Dimethyl-4,5-bis(3-methyl-2-thioxo-2,3-dihydro-1H-imidazol-1-ylmethyl)-1,3-dioxolane
In the chiral title compound, C15H22N4O2S2, there are two molecules in the asymmetric unit with distinctly different conformations, as quantified by torsion angles. The dihedral angles between the thioimidazole rings are 81.59 (5) and 67.04 (4)°. One molecule exhibits local twofold rotation symmetry, while the other displays no local symmetry. Intermolecular C—H⋯O and C—H⋯S interactions are observed
Does laminated intraluminal thrombus within abdominal aortic aneurysm cause anoxia of the aortic wall?
Messenger RNA coding for only the alpha subunit of the rat brain Na channel is sufficient for expression of functional channels in Xenopus oocytes
Several cDNA clones coding for the high molecular weight (alpha) subunit of the voltage-sensitive Na channel have been selected by immunoscreening a rat brain cDNA library constructed in the expression vector lambda gt11. As will be reported elsewhere, the amino acid sequence translated from the DNA sequence shows considerable homology to that reported for the Electrophorus electricus electroplax Na channel. Several of the cDNA inserts hybridized with a low-abundance 9-kilobase RNA species from rat brain, muscle, and heart. Sucrose-gradient fractionation of rat brain poly(A) RNA yielded a high molecular weight fraction containing this mRNA, which resulted in functional Na channels when injected into oocytes. This fraction contained undetectable amounts of low molecular weight RNA. The high molecular weight Na channel RNA was selected from rat brain poly(A) RNA by hybridization to a single-strand antisense cDNA clone. Translation of this RNA in Xenopus oocytes resulted in the appearance of tetrodotoxin-sensitive voltage-sensitive Na channels in the oocyte membrane. These results demonstrate that mRNA encoding the alpha subunit of the rat brain Na channel, in the absence of any beta-subunit mRNA, is sufficient for translation to give functional channels in oocytes
EVERYTHING COUNTS: Building a Control Regime for Nonstrategic Nuclear Warheads in Europe
Before the Russian invasion of Ukraine, the Biden administration insisted in arms control talks with Russia that a follow-on agreement to the New Strategic Arms Reduction Treaty (New START) should cover all nuclear weapons and that such an agreement should focus on the nuclear warheads themselves. This would represent a significant change from previous agreements, which focused on delivery vehicles, such as missiles. The United States has been particularly interested in potential limits on nonstrategic nuclear warheads (NSNW). Such weapons have never been subject to an arms control agreement. Because Russia possesses an advantage in the number of such weapons, the US Senate has insisted that negotiators include them in a future agreement, making their inclusion necessary if such an accord is to win Senate approval and ultimately be ratified by Washington. In the wake of Russian nuclear threats in the Ukraine conflict, such demands can only be expected to grow if and when US and Russian negotiators return to the negotiating table
Strong and weak lensing united III: Measuring the mass distribution of the merging galaxy cluster 1E0657-56
The galaxy cluster 1E0657-56 (z = 0.296) is remarkably well-suited for
addressing outstanding issues in both galaxy evolution and fundamental physics.
We present a reconstruction of the mass distribution from both strong and weak
gravitational lensing data. Multi-color, high-resolution HST ACS images allow
detection of many more arc candidates than were previously known, especially
around the subcluster. Using the known redshift of one of the multiply imaged
systems, we determine the remaining source redshifts using the predictive power
of the strong lens model. Combining this information with shape measurements of
"weakly" lensed sources, we derive a high-resolution, absolutely-calibrated
mass map, using no assumptions regarding the physical properties of the
underlying cluster potential. This map provides the best available
quantification of the total mass of the central part of the cluster. We also
confirm the result from Clowe et al. (2004,2006a).Comment: Accepted for publication in ApJ; Version with full-resolution figures
available at
http://www.slac.stanford.edu/~marusa/Work/bradac_strong_weak_III.pd
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