Brain Amino Acids and Biogenic Amines Under Various Atmospheric Mixtures Semiannual Report, May - 31 Oct. 1966

Brain biochemistry of rats exposed to pure oxyge

Ito channels are octomeric complexes with four subunits of each Kv4.2 and K+ channel-interacting protein 2.

Mammalian voltage-gated K+ channels are assemblies of pore-forming alpha-subunits and modulating beta-subunits. To operate correctly, Kv4 alpha-subunits in the heart and central nervous system require recently identified beta-subunits of the neuronal calcium sensing protein family called K+ channel-interacting proteins (KChIPs). Here, Kv4.2.KChIP2 channels are purified, integrity of isolated complexes confirmed, molar ratio of the subunits determined, and subunit valence established. A complex has 4 subunits of each type, a stoichiometry expected for other channels employing neuronal calcium sensing beta-subunits

On the Enhanced Interstellar Scattering Toward B1849+005

(Abridged) This paper reports new Very Large Array (VLA) and Very Long Baseline Array (VLBA) observations of the extragalactic source B1849+005 at frequencies between 0.33 and 15 GHz and the re-analysis of archival VLA observations at 0.33, 1.5, and 4.9 GHz. The structure of this source is complex but interstellar scattering dominates the structure of the central component at least to 15 GHz. An analysis of the phase structure functions of the interferometric visibilities shows the density fluctuations along this line of sight to be anisotropic (axial ratio = 1.3) with a frequency-independent position angle, and having an inner scale of roughly a few hundred kilometers. The anisotropies occur on length scales of order 10^{15} cm (D/5 kpc), which within the context of certain magnetohydrodynamic turbulence theories indicates the length scale on which the kinetic and magnetic energy densities are comparable. A conservative upper limit on the velocity of the scattering material is 1800 km/s. In the 0.33 GHz field of view, there are a number of other sources that might also be heavily scattered. Both B1849+005 and PSR B1849+00 are highly scattered, and they are separated by only 13'. If the lines of sight are affected by the same ``clump'' of scattering material, it must be at least 2.3 kpc distant. However, a detailed attempt to account for the scattering observables toward these sources does not produce a self-consistent set of parameters for such a clump. A clump of H\alpha emission, possibly associated with the H II region G33.418-0.004, lies between these two lines of sight, but it seems unable to account for all of the required excess scattering.Comment: 23 pages, LaTeX2e AASTeX, 13 figures in 14 PostScript files, accepted for publication in Ap

An upper limit on anomalous dust emission at 31 GHz in the diffuse cloud [LPH96]201.663+1.643

[LPH96]201.663+1.643, a diffuse H{\sc ii} region, has been reported to be a candidate for emission from rapidly spinning dust grains. Here we present Cosmic Background Imager (CBI) observations at 26-36 GHz that show no evidence for significant anomalous emission. The spectral index within the CBI band, and between CBI and Effelsberg data at 1.4/2.7 GHz, is consistent with optically thin free-free emission. The best-fitting temperature spectral index from 2.7 to 31 GHz, $\beta=-2.06 \pm 0.03$, is close to the theoretical value, $\beta=-2.12$ for $T_{e}=9100$ K. We place an upper limit of 24% ~ (2\sigma) for excess emission at 31 GHz as seen in a 6\arcmin FWHM beam. Current spinning dust models are not a good fit to the spectrum of LPH96. No polarized emission is detected in the CBI data with an upper limit of 2% on the polarization fraction.Comment: 5 pages, 3 figures, submitted to ApJ

The solar system boron abundance

The concentrations of B in seven carbonaceous chondritic meteorites have been determined by the use of two different analytical techniques. The data correspond to a B/H ratio of about 10^(-9) compared to the value of 10^(-8) previously proposed by Cameron, Colgate, and Grossman. However, the meteoritic abundance remains at least a factor of 2-10 higher than various estimates of the solar photosphere abundance. We conclude that both meteoritic and photospheric B and Be abundances must be considered in comparisons with nucleosynthesis calculations. Using our revised B abundances and assuming ^7Li was synthesized in the big bang, we find that the residual ^6Li/1°B, ^9Be/^(10)B, and ^(11)B/^(10)B abundance ratios are well matched by the production rates for bombardment of a CNO mixture of solar proportions by protons and a-particles with a kinetic energy per nucleon spectrum of the form E^(-1.8)

Fundamental Cycles and Graph Embeddings

In this paper we present a new Good Characterization of maximum genus of a graph which makes a common generalization of the works of Xuong, Liu, and Fu et al. Based on this, we find a new polynomially bounded algorithm to find the maximum genus of a graph

Three-dimensional structure of I(to); Kv4.2-KChIP2 ion channels by electron microscopy at 21 Angstrom resolution.

Regulatory KChIP2 subunits assemble with pore-forming Kv4.2 subunits in 4:4 complexes to produce native voltage-gated potassium (Kv) channels like cardiac I(to) and neuronal I(A) subtypes. Here, negative stain electron microscopy (EM) and single particle averaging reveal KChIP2 to create a novel approximately 35 x 115 x 115 Angstrom, intracellular fenestrated rotunda: four peripheral columns that extend down from the membrane-embedded portion of the channel to enclose the Kv4.2 "hanging gondola" (a platform held beneath the transmembrane conduction pore by four internal columns). To reach the pore from the cytosol, ions traverse one of four external fenestrae to enter the rotundal vestibule and then cross one of four internal windows in the gondola