55 research outputs found
Special features of the Be2He fragmentation in emulsion at an energy of 1.2~A~GeV
The results of investigations of the relativistic Be nucleus
fragmentation in emulsion which entails the production of two He fragments of
an energy of 1.2~A~GeV are presented. The results of the angular measurements
of the Be2He events are analyzed.
The BeBe+n fragmentation channel involving the Be decay from
the ground (0) and the first excited (2) states to two
particles is observed to be predominant.Comment: 10 pages, 6 figures, conference: Conference on Physics of Fundamental
Interactions, Moscow, Russia, 5-9 Dec 2005 (Author's translation
Fragmentation of relativistic nuclei in peripheral interactions in nuclear track emulsion
The technique of nuclear track emulsions is used to explore the fragmentation
of light relativistic nuclei down to the most peripheral interactions - nuclear
"white" stars. A complete pattern of therelativistic dissociation of a B
nucleus with target fragment accompaniment is presented. Relativistic
dissociation Be is explored using significant statistics and
a relative contribution of Be decays from 0 and 2 states is
established. Target fragment accompaniments are shown for relativistic
fragmentation N3He+H and Ne5He. The leading role of the
electromagnetic dissociation on heavy nuclei with respect to break-ups on
target protons is demonstrated in all these cases. It is possible to conclude
that the peripheral dissociation of relativistic nuclei in nuclear track
emulsion is a unique tool to study many-body systems composed of lightest
nuclei and nucleons in the energy scale relevant for nuclear astrophysics.Comment: 15 pages, 4 figures, 4 tables, conference: Relativistic nuclear
physics: from Nuclotron to LHC energies, Kiev, June 18-22, 200
Clustering in light nuclei in fragmentation above 1 A GeV
The relativistic invariant approach is applied to analyzing the 3.3 A GeV
Ne fragmentation in a nuclear track emulsion. New results on few-body
dissociations have been obtained from the emulsion exposures to 2.1 A GeV
N and 1.2 A GeV Be nuclei. It can be asserted that the use of the
invariant approach is an effective means of obtaining conclusions about the
behavior of systems involving a few He nuclei at a relative energy close to 1
MeV per nucleon. The first observations of fragmentation of 1.2 A GeV B
and C nuclei in emulsion are described. The presented results allow one
to justify the development of few-body aspects of nuclear astrophysics.Comment: 7 pages, 8 figures, 3 tables, Nuclear Physics in Astrophysics-2,
16-20 May, 2005 (ATOMKI), Debrecen, Hungar
Electromagnetic dissociation of relativistic B nuclei in nuclear track emulsion
Experimental data on fragmentation channels in peripheral interactions of
B nuclei in nuclear track emulsions are presented. A detailed analysis made
it possible to justify selections of events of the electromagnetic-dissociation
process B Be + \emph{p} and to estimate its cross section. Events of
C peripheral dissociation that were observed in the same exposure are
described.Comment: 12 pages, 10 figures, 4 tables, Published in
Phys.Atom.Nucl.72:690-701,200
Kinetic barriers in the isomerization of substituted ureas: implications for computer-aided drug design
Unfolding Simulations of Holomyoglobin from Four Mammals: Identification of Intermediates and β-Sheet Formation from Partially Unfolded States
Myoglobin (Mb) is a centrally important, widely studied mammalian protein. While much work has investigated multi-step unfolding of apoMb using acid or denaturant, holomyoglobin unfolding is poorly understood despite its biological relevance. We present here the first systematic unfolding simulations of holoMb and the first comparative study of unfolding of protein orthologs from different species (sperm whale, pig, horse, and harbor seal). We also provide new interpretations of experimental mean molecular ellipticities of myoglobin intermediates, notably correcting for random coil and number of helices in intermediates. The simulated holoproteins at 310 K displayed structures and dynamics in agreement with crystal structures (R g ~1.48-1.51 nm, helicity ~75%). At 400 K, heme was not lost, but some helix loss was observed in pig and horse, suggesting that these helices are less stable in terrestrial species. At 500 K, heme was lost within 1.0-3.7 ns. All four proteins displayed exponentially decaying helix structure within 20 ns. The C- and F-helices were lost quickly in all cases. Heme delayed helix loss, and sperm whale myoglobin exhibited highest retention of heme and D/E helices. Persistence of conformation (RMSD), secondary structure, and ellipticity between 2-11 ns was interpreted as intermediates of holoMb unfolding in all four species. The intermediates resemble those of apoMb notably in A and H helices, but differ substantially in the D-, E- and F-helices, which interact with heme. The identified mechanisms cast light on the role of metal/cofactor in poorly understood holoMb unfolding. We also observed β-sheet formation of several myoglobins at 500 K as seen experimentally, occurring after disruption of helices to a partially unfolded, globally disordered state; heme reduced this tendency and sperm-whale did not display any sheet propensity during the simulations
Psycho-vegetative and somatic associations in patients with coronary heart disease
This literature review is focused on psycho-emotional status in patients with various clinical forms of coronary heart disease (CHD), as well as the specifics of autonomic regulation and clinical course, including CHD prognosis. The authors describe selected methods for objective dynamic assessment of these characteristics and their interrelations
A local dynamic structure of lysozyme in a spin-labeled tetragonal crystal at varying humidity.
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