783 research outputs found
The nucleotide sequence of the 5S ribosomal-RNA of <i>Actinia equina</i> and <i>Sepia officinalis</i>
The sequence of the 5.8 S ribosomal RNA of the crustacean <i>Artemia salina</i>. With a proposal for a general secondary structure model for 5.8 S ribosomal RNA
We report the primary structure of 5.8 S rRNA from the crustacean Artemia salina. The preparation shows length heterogeneity at the 5′-terminus, but consists of uninterrupted RNA chains, in contrast to some insect 5.8 S rRNAs, which consist of two chains of unequal length separated in the gene by a short spacer. The sequence was aligned with those of 11 other 5.8 S rRNAs and a general secondary structure model derived. It has four helical regions in common with the model of Nazar et al. (J. Biol. Chem. 250, 8591–8597 (1975)), but for a fifth helix a different base pairing scheme was found preferable, and the terminal sequences are presumed to bind to 28 S rRNA instead of binding to each other. In the case of yeast, where both the 5.8 S and 26 S rRNA sequences are known, the existence of five helices in 5.8 S rRNA is shown to be compatible with a 5.8 S - 26 S rRNA interaction model
Left ventricular heart failure and pulmonary hypertension
In patients with left ventricular heart failure (HF), the development of pulmonary hypertension (PH) and right ventricular (RV) dysfunction are frequent and have important impact on disease progression, morbidity, and mortality, and therefore warrant clinical attention. Pulmonary hypertension related to left heart disease (LHD) by far represents the most common form of PH, accounting for 65–80% of cases. The proper distinction between pulmonary arterial hypertension and PH-LHD may be challenging, yet it has direct therapeutic consequences. Despite recent advances in the pathophysiological understanding and clinical assessment, and adjustments in the haemodynamic definitions and classification of PH-LHD, the haemodynamic interrelations in combined post- and pre-capillary PH are complex, definitions and prognostic significance of haemodynamic variables characterizing the degree of pre-capillary PH in LHD remain suboptimal, and there are currently no evidence-based recommendations for the management of PH-LHD. Here, we highlight the prevalence and significance of PH and RV dysfunction in patients with both HF with reduced ejection fraction (HFrEF) and HF with preserved ejection fraction (HFpEF), and provide insights into the complex pathophysiology of cardiopulmonary interaction in LHD, which may lead to the evolution from a ‘left ventricular phenotype’ to a ‘right ventricular phenotype’ across the natural history of HF. Furthermore, we propose to better define the individual phenotype of PH by integrating the clinical context, non-invasive assessment, and invasive haemodynamic variables in a structured diagnostic work-up. Finally, we challenge current definitions and diagnostic short falls, and discuss gaps in evidence, therapeutic options and the necessity for future developments in this context
Tar-MD in NMR-based structure determination as a tool for handling local flexibility: application to a linear heptapeptide.
The 18S ribosomal RNA sequence of the sea anemone <i>Ammonia sulcata</i> and its evolutionary position among other eukaryotes
Evolutionary trees based on partial small ribosomal subunit RNA sequences of 22 metazoa species have been published [(1988) Science 239, 748-753]. In these trees, cnidarians (Radiata) seemed to have evolved independently from the Bilateria, which is in contradiction with the general evolutionary view. In order to further investigate this problem, the complete srRNA sequence of the sea anemone Ammonia sulcata was determined and evolutionary trees were constructed using a matrix optimization method. In the tree thus obtained the sea anemone and Bilateria together form a monophyletic cluster, with the sea anemone forming the first line of descent of the metazoan group
Equivalence of Kinetic Theories of Bose-Einstein Condensation
We discuss the equivalence of two non-equilibrium kinetic theories that
describe the evolution of a dilute, Bose-Einstein condensed atomic gas in a
harmonic trap. The second-order kinetic equations of Walser et al. [PRA 63,
013607 (2001)] reduce to the Gross-Pitaevskii equation and the quantum
Boltzmann equation in the low and high temperature limits, respectively. These
kinetic equations can thus describe the system in equilibrium (finite
temperature) as well as in non-equilibrium (real time). We have found this
theory to be equivalent to the non-equilibrium Green's function approach
originally proposed by Kadanoff and Baym and more recently applied to
inhomogeneous trapped systems by M. Imamovi\'c-Tomasovi\'c and A. Griffin
[arXiv:cond-mat/9911402].Comment: REVTeX3, 6 pages, 2 eps figures, published version, minor change
Three month clinical results with a rechargeable sacral neuromodulation system for the treatment of overactive bladder
Three month clinical results with a rechargeable sacral neuromodulation system for the treatment of overactive bladder
Magnetic susceptibility of EuTe/PbTe Heisenberg superlattices: experimental and theoretical studies
We report results on the temperature dependence of the susceptibilities of a
set of MBE-grown short-period EuTe/PbTe antiferromagnetic superlattices having
different EuTe layer thicknesses. In-plane and orthogonal susceptibilities have
been measured and display a strong anisotropy at low temperature, confirming
the occurrence of a magnetic phase transition in the thicker samples, as seen
also in neutron diffraction studies. We suggest that dipolar interactions
stabilize antiferromagnetic long-range order in an otherwise isotropic system
and we present numerical and analytical results for the low-temperature
orthogonal susceptibility.Comment: 30 pages, 8 ps figures, RevTe
Early X-ray and optical observations of the soft gamma-ray repeater SGR 0418+5729
Emission of two short hard X-ray bursts on 2009 June 5 disclosed the
existence of a new soft gamma-ray repeater, now catalogued as SGR 0418+5729.
After a few days, X-ray pulsations at a period of 9.1 s were discovered in its
persistent emission. SGR 0418+5729 was monitored almost since its discovery
with the Rossi X-ray Timing Explorer (2-10 keV energy range) and observed many
times with Swift (0.2-10 keV). The source persistent X-ray emission faded by a
factor 10 in about 160 days, with a steepening in the decay about 19 days after
the activation. The X-ray spectrum is well described by a simple absorbed
blackbody, with a temperature decreasing in time. A phase-coherent timing
solution over the 160 day time span yielded no evidence for any significant
evolution of the spin period, implying a 3-sigma upper limit of 1.1E-13 s/s on
the period derivative and of 3E+13 G on the surface dipole magnetic field.
Phase-resolved spectroscopy provided evidence for a significant variation of
the spectrum as a function of the stellar rotation, pointing to the presence of
two emitting caps, one of which became hotter during the outburst. Finally, a
deep observation of the field of SGR 0418+5729 with the new Gran Telescopio
Canarias 10.4-m telescope allowed us to set an upper limit on the source
optical flux of i'>25.1 mag, corresponding to an X-ray-to-optical flux ratio
exceeding 10000, consistent with the characteristics of other magnetars.Comment: The paper (10 pages) contains 6 colour figures and 2 tables; accepted
for publication in MNRA
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