Synthesis and Antioxidant Activity of Ethyl 2-Amino-6-cyano-6-phenyl-4,5,6,7-tetrahydro-1-benzothiophene-3-carboxylates and 3-Amino-4-oxo-7-phenyl-3,4,5,6,7,8-hexahydrobenzo[4,5]thieno[2,3-d]pyrimidine-7-carbonitriles

Russian Journal of Organic Chemistry - Gewald reaction of 4-oxo-1-phenylcyclohexane-1-carbonitrile with ethyl cyanoacetate and elemental sulfur in the presence of diethylamine afforded ethyl...     

Elastic and rotational excitation cross-sections for electron-water collisions in the low- and intermediate-energy ranges

We present a theoretical study on electron-H2O collisions in the low- and intermediate-energy ranges. More specifically, we report calculated elastic differential, integral and momentum transfer cross-sections as well as rotational excitation cross-sections in the (2–500)-eV range. In our calculations, an optical potential is used to represent the electron-molecule interaction. The Schwinger variational method combined with the distorted-wave approximation is used to solve the scattering equations. The comparison of our calculated results with other theoretical and/or experimental data available in the literature is very encouraging.     

Dynamics of boron nanoclusters in RB12 (R = Yb,Lu) systems

The phonon dispersion in RB₁₂ (R = Yb, Lu) systems is studied in detail using inelastic neutron scattering over a wide range of energies (up to 55 meV). It is demonstrated that the main features of the lattice dynamics in the RB₁₂ crystals can be described in terms of a simple model of force constants with a strong hierarchy of interatomic interactions in the systems: B-B ≫ B-R ≫ R-R. An interesting feature of the low-energy portion of the phonon spectrum is the weakly dispersive optical mode. According to the model calculations, this mode is associated with the relative displacements and “breathing” vibrations of the boron nanoclusters B₁₂.

     

Spontaneous emission from Bloch states of a two-level atom in a periodic field of the biparabolic shape

By analogy with the Wigner-Weisskopf model, spontaneous emission of an atom is considered in a spatially periodic field of the resonance counter-propagating waves. The Bloch state obtained by the interaction of the initially excited (unexcited) atom with a field of the counter-propagating waves plays the role of the excited (ground) state of the free atom. The spontaneous emission probability averaged over polarizations is shown to become anisotropic, with the symmetry axis directed along the wave propagation path. The anisotropy is caused by the spatially periodic distribution of the wave function of the translational motion of an atom in the external field. The degree of anisotropy depends on the position of Bloch energy levels in the allowed bands of the energy spectrum.     

Radiation from 20 MeV electrons in piezoelectric single crystals in the presence of external acoustic fields

The radiation from electrons interacting with piezoelectric single crystals and the influence of acoustic fields on the frequency-temporal parameters of characteristic energy yields have been investigated experimentally. The experiments were carried out on the extracted 20 MeV electron beam of the linear accelerator LEA-50 of the Alikhanian National Scientific Laboratory. The energy distributions of specific yields of the electron radiation in quartz single crystal were obtained. The amplification of intensity and the shift of energy yields under the influence of hypersonic vibrations were observed.     

Investigation of laser-beam-induced photocurrent in planar two-dimensional <Emphasis Type=Italic>n-p-n</Emphasis> structures

The magnitude of photocurrent induced in two-dimensional n-p-n structures has been measured depending on the position of the focused laser beam incident at their surface. Studied samples were fabricated of p-doped GaAs/In_0.11Ga_0.89As/Al_0.33Ga_0.67As heterostructure by the local overcompensation doping with silicon. These structures exhibit high photosensitivity and the value of photocurrent induced in them varies linearly with the change in the position of the incident beam in almost the entire space between the two p-n junctions. An absolute position sensor based on 2D n-p-n structures has been designed and the spatial resolution of this coordinate-sensitive element was estimated.     

Thermography assessment of spastic lower limb in patients after cerebral stroke undergoing rehabilitation

Journal of Thermal Analysis and Calorimetry - Stroke contributes to disability in adulthood. The assessment of the degree of spasticity is one of the basic methods of patient examination after...     

The conjugative metabolism of 4-methylumbelliferone and deconjugation to the parent drug examined by isolated perfused liver and in vitro liver homogenate of rats

We examined the disposition of 4-methylumbelliferone (4-MU) and its conjugative metabolites, glucuronide (4-MUG) and sulfate (4-MUS), using a single-pass rat liver perfusion system. When 4-MU was delivered, the steady-state hepatic extraction ratio for 4-MU was very high (approximately 1.0) and its conjugative metabolites, 4-MUG and 4-MUS, appeared to a large extent in the effluent perfusate. The biliary excretion rate of the 4-MUG conjugated from 4-MU was 44% of the infusion rate at the steady-state, whereas those of 4-MU and 4-MUS were less than 1% of the infusion rate. When 4-MUG was delivered, the steady-state hepatic extraction ratio for 4-MUG was very low (less than 0.05) and the removal rate of 4-MUG from the perfusate was almost identical to the excretion rate of 4-MUG into the bile, while 4-MU and 4-MUS were slightly excreted into the bile (1% of the total biliary excretion rate), suggesting that a little deconjugation of 4-MUG to 4-MU occurred in the liver. Similarly, 4-MU and 4-MUS were not detectable in the effluent perfusate. The apparent extraction ratio (Eapp) for the intracellularly conjugated 4-MUG was approximately twenty times higher than that for the pre-conjugated 4-MUG. This discrepancy between the values of Eapp for the intracellularly conjugated and pre-conjugated 4-MUG might be attributed mainly to the diffusional barrier for the metabolite between the blood and hepatocytes, as suggested in the previous simulation (J. Pharmacokin, Biopharm., 15, 399 (1987].(ABSTRACT TRUNCATED AT 250 WORDS)