Deterioration in Hemodynamics Reaction, Baroreflex Sensitivity, Sympathetic Nerve Activity and Redox State of Thoracic Aorta in the Experimental Model of Nitrate Tolerance and Its Pharmacological Correction

Continuous treatment with organic nitrates causes nitrate tolerance and provides evidence for a relationship between mitochondrial complex 1 activity and mitochondrial aldehyde dehydrogenase-2 (ALDH-2) with disturbances of the hemodynamics reaction during nitroglycerin (NTG) tolerance (NTGT). The purpose of this study was the evaluation of efficacy of original oxidized form NAD-containing drug, NADCIN®, on hemodynamic reactions, baroreflex sensitivity (BRS) and reflex control of splanchnic sympathetic nerve activity (SSNA), level of redox-potential, activity of ALDH-2 and superoxide anion generation in aortic tissue in rat model of NTGT. Five groups (7 - 9 each) of male Wistar rats, including control, acute i.v. NTG (150 mcg/kg) administration, NTG tolerance NTGT treatment with NADCIN® 8 mg/kg and methylene blue (MB, 2.5 mg/kg) were used. NTGT in rats was accompanied with the greatly attenuation of hemodynamics reaction, BRS, the decreasing of the ability to reflex control of SSNA without pronounce overexpression of endothelin-1 in vessels (aorta). In NTGT rats i.v. NTG along induced less hypotensive reactions and alterations in heart period vs single NTG treated group, more expressively decreased BRS (-34%) and reflex control of SSNA (-18%). NADCIN® significantly inhibits tolerance-inducing properties of the prolonged nitroglycerin infusion (max decrease of blood pressure response to nitroglycerin injection, % of normal controls: NTGT 51.2%, NADCIN® 91.6%, MB 55.8%). NADCIN® in NTGT rats after NTG i.v. administration increased reduced BRS (+37.8%, p < 0,05), reflex control of SSNA (+29.4%, p < 0.05) and reversed the decreasing of NAD/NADH ratio, ALDH-2 activity and decreasing in superoxide generation in thoracic aortic tissue. Thus, course treatment with NADCIN® of NTGT rats restores hemodynamics changes, BRS and SSNA throughout the increasing of redox-potential NAD/NADH and cessates the NTGT developing.

On the Bifurcations of Dean Flow between Porous Horizontal Cylinders with a Radial Flow and a Radial Temperature Gradient

The stability of a heat-conducting flow due to the pumping of a fluid around the annulus of horizontal porous cylinders is studied. The basic flow is under the action of radial flow and a radial temperature gradient. The objects of investigations are different regimes and bifurcations which may arise in this flow.

Quantum-Chemical Description of Influence of the R-Groups on Formation of Peptide Bond

The description of influence of the R-groups on formation of the peptide bond by quantum-chemical method of density functional theory (DFT) is carried out. The criterion of probability of formation of the peptide bond has been constructed. In particular it is shown that the propensity to formation of the peptide bond is increased as a result of 1) decrease of the CO and NH bond orders (PCO and PNH) and of activation energy (ΔE#), 2) increase of OH and CN bond orders (POH and PCN), 3) exothermic property of this reaction (ΔE < 0).

Crystallization of amorphous boron by the calorimetric method

The kinetics of formation of crystal boron was studied by X-ray structure and differential-thermal analyses. The enthalpy of transition of amorphous boron to crystal boron with formation of an intermediate non-equilibrium phase was determined by the calorimetric method. Studies were carried out by using the differential scanning calorimeter SETARAM. Amorphous boron received by diboron cracking was used as the starting material. The test sample is cha- racterized by stability even at a high temperature. When heated, amorphous boron first transforms to crystal boron of α-modification, and during a further heating, there occur several phase transitions, which means the transition of α-rhombohedric crystal boron to the β'?and β''?metastable states. Studies of various modifications were carried out by radiographic and electro-optic methods. The high sensitiveness of the calorimeter made it possible to control temperature in the oven, make records and detect even the smallest thermal effects.

Two-step exhumation of Caucasian intraplate rifts:A proxy of sequential plate-margin collisional orogenies

Intraplate structural deformation is diagnostic of tectonic stress regime changes linked to plate interactions and can result from superposed tectonic events whose single contributions are hardly distinguishable.In this paper,we present a set of integrated thermochronologic inverse models along a 140 km-long transect across the central Greater Caucasus and the adjacent Adjara-Trialeti fold-and-thrust belt of Georgia,two intraplate orogens produced by structural inversion of parallel continental rift zones located on the Eurasian plate.Our dataset allows to distinguish discrete and superposed deformation episodes and quantify their respective contributions to orogenic exhumation.The integration of(U-Th)/He analysis on apatite and zircon,fission-track analysis on apatite,and peak-temperature determinations(clay mineralogy,organic matter petrography,Raman spectroscopy)shows that structural inversion was punctuated by two incremental steps starting respectively in the latest Cretaceous and the mid-Miocene.Latest Cretaceous partial inversion of the Greater Caucasus is documented here for the first time and placed in a geographically wider context of coeval deformation.The two episodes of intraplate structural inversion,exhumation,and sediment generation are chronologically and physically correlated with docking of(i)the Anatolide-Tauride-Armenian terrane(Late Cretaceous-Paleocene)and(ii)Arabia(Miocene hard collision)against the southern Eurasian plate margin.Intraplate deformation in the Caucasian domain was triggered by far-field propagation of plate-margin collisional stress which focused preferentially along rheologically weak rift zones.