Induced emission of Alfvén waves in inhomogeneous streaming plasma: implications for solar corona heating and solar wind acceleration.

The results of a self-consistent kinetic model of heating the solar corona and accelerating the fast solar wind are presented for plasma flowing in a nonuniform magnetic field configuration of near-Sun conditions. The model is based on a scale separation between the large transit or inhomogeneity scales and the small dissipation scales. The macroscale instability of the marginally stable particle distribution function compliments the resonant frequency sweeping dissipation of transient Alfvén waves by their induced emission in inhomogeneous streaming plasma that provides enough energy for keeping the plasma temperature decaying not faster than r(-1) in close agreement with in situ heliospheric observations.

First-principles study of elastic and stability properties of ZrC-ZrN and ZrC-TiC alloys.

Ab initio calculations of the elastic constants for several cubic ordered structures of zirconium carbonitride (ZrC(x)N(1-x)) and zirconium-titanium carbide (Zr(x)Ti(1-x)C) alloys were carried out. The calculations of total and formation energies, bulk modulus and elastic constants as functions of composition were performed with an ab initio pseudo-potential method. The predicted equilibrium lattice parameters are slightly higher than those found experimentally (on average by 0.2-0.4%). The predicted formation energies indicate that the ZrC(x)N(1-x) alloys are stable even at 0 K in the whole concentration range, while the homogeneous Zr(x)Ti(1-x)C alloys can be stabilized only at high temperatures. Spinodal decomposition of the latter alloys into cubic domains takes place over a wide range of compositions and temperatures. For the carbonitrides, the shear modulus G, the Young's modulus E and the Poisson ratio σ reach an extremum for carbon-rich alloys, and this is attributed to a maximum value of the shear modulus C(44) that corresponds to a valence-electron concentration in the range of 8.2-8.3. This extremal behavior finds its origin in the response of the band structure of ZrC(x)N(1-x) alloys for 0≤x≤1, caused by the monoclinic strain that determines this shear modulus. In contrast, the other shear modulus [Formula: see text] does not exhibit any extremum over the whole composition range. These results are in contrast with those for Zr-Ti carbides for which the elastic properties gradually increase from ZrC to TiC.

The human cardiac muscle ryanodine receptor-calcium release channel: identification, primary structure and topological analysis.

Rapid Ca2+ efflux from intracellular stores during cardiac muscle excitation-contraction coupling is mediated by the ryanodine-sensitive calcium-release channel, a large homotetrameric complex present in the sarcoplasmic reticulum. We report here the identification, primary structure and topological analysis of the ryanodine receptor-calcium release channel from human cardiac muscle (hRyR-2). Consistent with sedimentation and immunoblotting studies on the hRyR-2 protein, sequence analysis of ten overlapping cDNA clones reveals an open reading frame of 14901 nucleotides encoding a protein of 4967 amino acid residues with a predicted molecular mass of 564 569 Da for hRyR-2. In-frame insertions corresponding to eight and ten amino acid residues were found in two of the ten cDNAs isolated, suggesting that novel, alternatively spliced transcripts of the hRyR-2 gene might exist. Six hydrophobic stretches, which are present within the hRyR-2 C-terminal 500 amino acids and are conserved in all RyR sequences, may be involved in forming the transmembrane domain that constitutes the Ca(2+)-conducting pathway, in agreement with competitive ELISA studies with a RyR-2-specific antibody. Sequence alignment of hRyR-2 with other RyR isoforms indicates a high level of overall identity within the RyR family, with the exception of two important regions that exhibit substantial variability. Phylogenetic analysis suggests that the RyR-2 isoform diverged from a single ancestral gene before the RyR-1 and RyR-3 isoforms to form a distinct branch of the RyR family tree.

Calcium oscillations in mammalian eggs triggered by a soluble sperm protein.

At fertilization in mammals, the sperm induces a characteristic series of Ca2+ oscillations in the egg which serve as the essential trigger for egg activation and early development of the embryo. It is not known how the sperm initiates this fundamental process, however, nor has any pathway linking sperm-egg membrane-receptor binding with intracellular Ca2+ release been demonstrated. Microinjection of sperm extracts into mammalian eggs elicits Ca2+ oscillations identical to those occurring at fertilization, which suggests that sperm may introduce a Ca2+ oscillation-inducing factor into the egg on gamete membrane fusion. Here we identify a soluble sperm protein that exhibits Ca2+ oscillation-inducing ('oscillogen') activity in eggs. Sperm oscillogen exists as an oligomer with a subunit of M(r) 33K and a specific intracellular localization at the equatorial segment of the sperm head. Cloning of the 33K oscillogen complementary DNA indicates similarity with a hexose phosphate isomerase found in prokaryotes. This sperm-derived oscillogen, termed oscillin, may represent the physiological trigger for development in mammals.

[The prospects for the use of computers in dentistry]. / Perspektivy primeneniia EVM v stomatologii.

A universal soft-art complex tentatively named Arm-Stomatolog, covering all sections of dentistry, has been developed. It is based on individual programs in dentistry, making use of high-level algorithmic languages fitted to modern operation systems and permitting block-to-block fitting of individual programs to unite them in a complex.

Expression and characterization of the bovine histamine H1 receptor in cDNA-transfected C6 astroglioma cells.

Rat C6 astroglioma cells (C6-bH1R cells) expressing cloned bovine histamine H1 receptors were established by transfection with a vector (pEF-BOS-bH1R) which carried a 2.7-kbp EcoRI fragment of the bovine H1 receptor cDNA [Yamashita, M. et al. (1991) Proc. Natl. Acad. Sci. USA 88, 11515-11519]. The cloned bovine H1 receptor in C6-bH1R cells was characterized by three established criteria: the [3H]mepyramine binding assay, the accumulation of inositol phosphates induced by histamine, and histamine-induced elevation of intracellular Ca2+ concentration ([Ca2+]i). The accumulation of inositol phosphates induced by histamine was time- and dose-dependent. The accumulation of inositol trisphosphate was biphasic with a prompt increase to the maximal level, followed by a sustained submaximal level. The histamine-induced accumulation of inositol phosphates was suppressed by phorbol ester, but not by pertussis toxin. Results from the [3H]-mepyramine binding assay and histamine-induced elevation of [Ca2+]i were characteristic of H1 receptors. Several compounds among tricyclic antidepressants, neuroleptics, and serotonin antagonists showed affinities to the cloned bovine H1 receptor with Ki values similar to reported values. Histamine neither induced cAMP accumulation nor attenuated forskolin-induced cAMP accumulation in C6-bH1R cells. C6-bH1R cells are particularly useful for studying the H1 receptor-mediated astroglial cell functions.

Prostaglandin F2 alpha receptor is coupled to Gq in cDNA-transfected Chinese hamster ovary cells.

We examined intracellular signal transduction of prostaglandin F2 alpha (PGF2 alpha) receptors by transfection and stable expression of the receptor cDNA in Chinese hamster ovary (CHO-PGF2 alpha) cells. The binding to the membrane was specific for PGF2 alpha, and the Scatchard plot analysis showed a single high-affinity binding site (Kd = 25.2 nM). PGF2 alpha gradually elevated intracellular Ca2+ and stimulated phosphoinositide metabolism in CHO-PGF2 alpha cells. In whole-cell clamp recordings, PGF2 alpha induced an outward current in the presence of external Ca2+, but it induced a long-lasting inward Ca2+ current in a Na(+)-free solution containing K+ channel blockers. Gq alpha antibody applied intracellularly blocked both outward and inward currents induced by 1 microM PGF2 alpha. These results demonstrate that the PGF2 alpha receptor is coupled to phosphoinositide metabolism in CHO-PGF2 alpha cells via Gq.

[Folic acid in the combined treatment of patients with disseminated sclerosis and chronic gastritis]. / Folievaia kislota v kompleksnom lechenii bol'nykh rasseiannym sklerozom s khronicheskim gastritom.

Folic acid was used for the complex treatment of patients with multiple sclerosis. The doses employed were 200-300 mcg daily. It was established that folic acid improved the reparative processes in the gastric mucosa and produced a pronounced therapeutic effect on the neurological status of the patients, favoured improvement of their general condition.

[Statistical patterns of the formation of acrocentric chromosome associations in human peripheral blood lymphocytes]. / Statisticheskie zakonomernosti obrazovaniia assotsiatsii akrotsentricheskikh khromosom v limfotsitakh perifericheskoi krovi cheloveka.

The level of the association index of acrocentric chromosomes in lymphocyte population of peripheral blood depends on a frequency of lymphocyte classes with different numbers of associating of chromosomes and is not related to argentophily of their nucleolus formating regions. The latter character influences the frequency of entry of separate acrocentric chromosomes in appearing associations.

[Leukocytic reaction of peripheral blood in patients who died at different stages of myocardial infarction]. / Leikotsitarnye reaktsii perifericheskoi krovi u bol'nykh infarktom miokarda, umershikh v raznye sroki zabolevaniia.

Peripheral leucocyte changes were studied in diseased myocardial infarction patients. Disorders of blood and infarcted-area leucocyte kinetics were shown to be prominent among cardiac and extracardiac causes of death from myocardial infarction. Their control may provide a method of pathogenetic treatment for the disease.

[Form of branching of pulmonary air pathways in the canine lung]. / Forma razvetvleniia vozdukhonosnykh putei legkogo sobaki.

The degree of regularity in bronchial dichotomy has been studied in 5 corrosive preparations of the dog bronchial tree by the method of E. R. Weibel. It has been demonstrated that a high degree of regularity is specific for the dog lungs that makes 0.82 +/- 0.12 regarding small and large diameters. Approximation in distribution of bronchi having the diameter of 3--3.5 mm in 1--9 generations by means of binomial distribution gives a good result. The greatest bronchial rate with the diameter mentioned above has been registered in 5--7 generations. Theoretical data are presented to demonstrate the necessity in regularity of bronchial branching in order to maintain an optimal gaseous exchange in lungs.

[Multimeasurement analysis of the quantitative spatial organization of epicardial lymphatic capillaries under normal conditions]. / Mnogomernyi analiz kolichestvenno-prostranstvenmoi organizatsii limfaticheskikh kapilliarov épikarda v norme.

Principles of quantitative-spatial organization of the epicardial lymphatic capillaries have been studied in 26 normal dogs' hearts. Multimeasurable systemic models have been constructed to demonstrate how quantitative indices of metrical properties of the capillaries depend on the cardiac size. The possibility is discussed to apply the data obtained in the study of microcirculatory pathology of different genesis.