523 research outputs found
Integrative Approach - New Level Knowledge of Functions: Opportunities and Prospects
In this article, the example of the mechanisms of heart rhythmogenesis in the intact organism is used to demonstrate the new capabilities provided by an integrative approach. It is shown that the rhythm is formed in the brain, transmitted to the heart in the form of signals along the vagus nerves and reproduces the heart. Evidence: the heart rhythm reproduces the natural efferent signals in the vagus nerves in the cardio-respiratory synchronism and in the intact organism sino-atrial node performs the functions of the latent pacemaker. Integration of the two hierarchical levels of rhythmogenesis (brain and intracardiac) provides the reliability and functional perfection of cardiac rhythm generation in the body. It is expedient to extend the presented methodology for scientific analysis to other organism systems
Cardiovascular effects of an arginase II selective inhibitor
For the first time in vitro experiments there were studied the inhibitory activity and safety of potential molecules arginase II selective inhibitors from the group of norleucine derivatives. Also first the substance under the code ZB49-0010C from the group of norleucine derivatives showed the greatest selectivity and inhibitory activity against arginase II in experiments in vitro. However, this substance in vivo exerts dose-dependent hypotensive action and cardioprotective and endothelial protective effects on the L-NAME induced and homocysteine-induced endothelial dysfunction (ED), which are most pronounced at a dose of 10 mg/kg in intragastric administratio
Contributions of spontaneous phase slippage to linear and non-linear conduction near the Peierls transition in thin samples of o-TaS_3
In the Peierls state very thin samples of TaS_3 (cross-section area \sim
10^{-3} mkm^2) are found to demonstrate smearing of the I-V curves near the
threshold field. With approaching the Peierls transition temperature, T_P, the
smearing evolves into smooth growth of conductance from zero voltage
interpreted by us as the contribution of fluctuations to the non--linear
conductance. We identify independently the fluctuation contribution to the
linear conductance near T_P. Both linear and non-linear contributions depend on
temperature with close activation energies \sim (2 - 4) x 10^3 K and apparently
reveal the same process. We reject creep of the {\it continuous} charge-density
waves (CDWs) as the origin of this effect and show that it is spontaneous phase
slippage that results in creep of the CDW. A model is proposed accounting for
both the linear and non-linear parts of the fluctuation conduction up to T_P.Comment: 6 pages, 5 Postscript figure, RevTeX, accepted for publication in PR
Retinoprotective Effect of 2‐Ethyl‐3‐hydroxy‐6‐methylpyridine Nicotinate
An important task of pharmacology is to find effective agents to improve retinal microcirculation and resistance to ischemia. The purpose of the study is to pharmacologically evaluate the retinoprotective effect of 2-3-hydroxy-6-methylpyridine nicotinate in a rat model of retinal ischemia-reperfusio
Human recombinant erythropoietin gradient dosage influence on ischemic and reperfusion liver injury
We investigate influence of human recombinant erythropoietin different dosage on blood flow velocity and morphological changes in liver during ischemic and reperfusion injury. It was proved what optimal preconditioning dosage is 50 IU/k
Fermion Analogy for Layered Superconducting Films in Parallel Magnetic Field
The equivalence between the Lawrence-Doniach model for films of extreme
type-II layered superconductors and a generalization of the back-scattering
model for spin-1/2 electrons in one dimension is demonstrated. This fermion
analogy is then exploited to obtain an anomalous tail for
the parallel equilibrium magnetization of the minimal double layer case in the
limit of high parallel magnetic fields for temperatures in the
critical regime.Comment: 11 pages of plain TeX, 1 postscript figur
The 3d-to-4s-by-2p highway to superconductivity in cuprates
High-temperature superconductors are nowadays found in great variety and hold
technological promise. It is still an unsolved mystery that the critical
temperature T_c of the basic cuprates is so high. The answer might well be
hidden in a conventional corner of theoretical physics, overlooked in the
recent hunt for exotic explanations of new effects in these materials. A
forgotten intra-atomic s-d two-electron exchange in the Cu atom is found to
provide a strong (~eV) electron pairing interaction. A
Bardeen-Cooper-Schrieffer approach can explain the main experimental
observations and predict the correct d_{x^2-y^2} symmetry of the gap.Comment: 4 pages, 3 figures, LaTeX2
Disorder-driven superconductor-normal metal phase transition in quasi-one-dimensional organic conductors
Effects of non-magnetic disorder on the critical temperature T_c and on
diamagnetism of quasi-one-dimensional superconductors are reported. The energy
of Josephson-coupling between wires is considered to be random, which is
typical for dirty organic superconductors. We show that this randomness
destroys phase coherence between wires and that T_c vanishes discontinuously at
a critical disorder-strength. The parallel and transverse components of the
penetration-depth are evaluated. They diverge at different critical
temperatures T_c^{(1)} and T_c, which correspond to pair-breaking and
phase-coherence breaking respectively. The interplay between disorder and
quantum phase fluctuations is shown to result in quantum critical behavior at
T=0, which manifests itself as a superconducting-normal metal phase transition
of first-order at a critical disorder strength.Comment: 12 pages, 3 figure
Correction of Experimental Retinal Ischemia by L-Isomer of Ethylmethylhydroxypyridine Malate
An important task of pharmacology and ophtalmology is to find specific and highly effective agents for correcting retinal ischemia. The objective of this study is to increase the effectiveness of pharmacological correction of retinal ischemia by using new 3-hydroxypyridine derivative-L-isomer of ethylmethylhydroxypyridine malat
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