[Effect of cysteine lithium salt on lipid peroxidation in the model of dopaminergic system disorder].

The antioxidant activity of a newly synthesized compound, cysteine lithium salt, was discovered using methyl oleate oxidation model of dopaminergic system disorder. Experimental data show that injection of the synthesized compound in animals with experimentally induced L-DOPA brings to normalization effect conditioned by inhibiting free radical reactions in the nuclear and mitochondrial fractions of brain cells. Antioxidant effect of the synthesized compound is related to its chemical structure that contains cysteine--an agent involved in the biosynthesis of glutathione, which is a component of glutathione peroxidase and glutathione reductase enzymes participating in the antiradical protection system.

Plasmonic nano-structures for optical data storage.

We propose a method of optical data storage that exploits the small dimensions of metallic nano-particles and/or nano-structures to achieve high storage densities. The resonant behavior of these particles (both individually and in small clusters) in the presence of ultraviolet, visible, and near-infrared light may be used to retrieve pre-recorded information by far-field spectroscopic optical detection. In plasmonic data storage, a very short (approximately few femtoseconds) laser pulse is focused to a diffraction-limited spot over a small region of an optical disk containing metallic nano-structures. The digital data stored in each bit-cell, comprising multiple bits of information, modifies the spectrum of the incident light pulse. This spectrum is subsequently detected, upon reflection/transmission, with the aid of an optical spectrum analyzer. We present theoretical as well as preliminary experimental results that confirm the potential of plasmonic nano-structures for high-density optical data storage applications.

[Neutral and acid glycolipids in the brain in the presence of ischemia and during antioxidant treatment].

The content of lipid peroxidation products and the metabolism of gangliosides and galactosylceramides in brain tissue were studied in the presence of ischemia and when an agent containing nicotinic acid and cysteine is administered. The above agent was found to have an antioxidative effect that was evident in the lower levels of lipid peroxides and in the normalized qualitative and quantitative content of galactosylceramides and gangliosides.

[Immunogenetic blood markers as a risk factor of development of periodic disease in Armenian population].

AIM: To reveal characteristic associations between various markers of immunogenetic (HLA--A, B, C, DR), erythrocytic (ABO, Rh-Hr, MNSs, Pp, Kell-Chellano, Lewis), serum (Gm, Inv) systems and familial Mediterranean fever (FMF) in Armenian population. MATERIAL AND METHODS: From 41 to 125 patients (depending on systems studied) were examined. HLA-antigens of A-, B-, C-classes were detected by the microcytotoxic test in a total population of lymphocytes, HLA-DR antigens--by a prolonged test in B-lymphocytes, erythrocytic antigens--by hemagglutination technique and indirect Coombs' reaction, serum antigens--by the method of hemagglutination suppression. RESULTS: Confidential positive associative relations between antigens HLA-A1 and A9 (RR = 2.2 and 2.4), HLA B5 and B35 (RR = 3.03 and 3.2), HLA-Cw4 (RR = 4.3), HLA-DR3 (RR = 2.6), phenotypes AB (RR = 2.86) and MN (RR = 2.2), serum antigen Gmx+ (RR = 2.87) were demonstrated. Simultaneous expression of phenotype MN and antigen Gmx+ is a marker of high predisposition to the disease (RR = 4.7). Negative associative relations were found between FMF and antigens HLA-B12 and B18 (RR = 0.6 and 0.1), HLA DR4 (RR = 0.1) and phenotype MM (RR = 0.37). CONCLUSION: A simultaneous complex investigation of the markers of various immunogenetic systems allows detection of genetic markers of predisposition to FMF (HLA-B5, B35, Cw4, DR3, AB, Gmx+, MN) and the resistance to this disease (HLA-B12, B18, DR4) in a population of Armenians.

Single-beam trapping of micro-beads in polarized light: Numerical simulations.

Using numerical solutions of Maxwell's equations in conjunction with the Lorentz law of force, we compute the electromagnetic force distribution in and around a dielectric micro-sphere trapped by a focused laser beam. Dependence of the optical trap's stiffness on the polarization state of the incident beam is analyzed for particles suspended in air or immersed in water, under conditions similar to those realized in practical optical tweezers. A comparison of the simulation results with available experimental data reveals the merit of one physical model relative to two competing models; the three models arise from different interpretations of the same physical picture.

Transmission of light through periodic arrays of sub-wavelength slits in metallic hosts.

Using Bloch modes to study the extraordinary transmission of light through a periodic array of slits in a metallic host, we discuss the differing roles of surface plasmon polaritons and Wood's anomalies in the observed behavior of such structures. Under certain circumstances, the first few excited modes appear to play a decisive role in determining the transmission efficiency of the array. Surface plasmon excitations tend to reduce the transmissivity of a semi-infinitely thick slit array, yet, paradoxically, the same reduction can account for enhanced transmission in an array of finite thickness tau, provided that tau is tuned to a Fabry-Perot-like resonance between the entrance and exit facets of the slit array. At the Wood anomaly, power redistribution produces sharp peaks in the diffraction efficiencies of various reflected and transmitted orders of the semi-infinite structure. With skew incidence, the degenerate states split, resulting in two peaks and two valleys, as observed by Wood in his 1902 experiments.

Electromagnetic field structure and normal mode coupling in photonic crystal nanocavities.

The electromagnetic field of a high-quality photonic crystal nanocavity is computed using the finite difference time domain method. It is shown that a separatrix occurs in the local energy flux discriminating between predominantly near and far field components. Placing a two-level atom into the cavity leads to characteristic field modifications and normal-mode splitting in the transmission spectra.

Transmission of light through small elliptical apertures.

The results of computer simulations based on the Finite Difference Time Domain method with local space and time grid refinement, are presented for an elliptical aperture in a thin metal film illuminated by a normally incident, monochromatic plane wave. Both cases of incident polarization parallel and perpendicular to the long axis of the ellipse are considered. An intuitive description of the behavior of the electromagnetic fields is developed in each case, and simulation results that exhibit patterns similar to those expected from this qualitative analysis are presented. The simulations reveal, in quantitative detail, the amplitude and phase behavior of the E- and B-fields in and around the aperture.

Late Proterozoic and Paleozoic Tides, Retreat of the Moon, and Rotation of the Earth

The tidal rhythmites in the Proterozoic Big Cottonwood Formation (Utah, United States), the Neoproterozoic Elatina Formation of the Flinders Range (southern Australia), and the Lower Pennsylvanian Pottsville Formation (Alabama, United States) and Mansfield Formation (Indiana, United States) indicate that the rate of retreat of the lunar orbit is dxi/dt approximately k2 sin(2delta) (where xi is the Earth-moon radius vector, k2 is the tidal Love number, and delta is the tidal lag angle) and that this rate has been approximately constant since the late Precambrian. When the contribution to tidal friction from the sun is taken into account, these data imply that the length of the terrestrial day 900 million years ago was approximately18 hours.

[Vocational rehabilitation of patients after radical surgery for stomach cancer]. / Trudovaia reabilitatsiia radikalno operirovannykh bolnykh rakom zheludka.

The authors analyse the dynamics of the working capacity of 146 patients with stomach carcinoma according to the type of operative treatment and the character of the work. The results of vocational rehabilitation were best after Billroth I subtotal resection; by the end of a 5-year follow-up period 81.8 +/- 8.2% of the patient who had survived worked (after Billroth II resection 57.8 +/- 7.4%, p < 0.05). After gastrectomy patients resumed work at more later periods. Lethality among parsons who resumed work was independent of the type of operation and was not higher than that among patients who did not work (8.2 +/- 2.3% and 62.6 +/- 2.5%, respectively; p < 0.001). Individuals of intellectual vocations returned earlier to their work after treatment (76.5 +/- 5.9% resumed work in the first 2 years, as compared to 42.1 +/- 5.1% of persons engaged in physical work; p < 0.001). The main tendency was to change to easier conditions of work, with the exception of highly qualified and highly specialized profession. Most of the patients (99 +/- 0.7%) resumed work in the first 4 years after the end of treatment.

[The pathochemical mechanisms of bronchospasm after physical exertion in bronchial asthma patients]. / Patokhimicheskie mekhanizmy bronkhospazma posle fizicheskogo usliliia u bol'nykh bronkhial'noi astmoi.

As many as 71 bronchial asthma (BA) patients and 12 patients suffering from chronic asthmatic bronchitis were examined in the stage of subsiding exacerbation. Before and 10 minutes after exercise measurements were made of the blood content of histamine (H), PGF2 alpha and PGE, adrenaline (A) and noradrenaline (NA), hydroperoxides (HP), and of the general and non-protein thiol groups. The initial level of H, PGF2 alpha, HP, A and NA was so much higher than the control value and the degree of its increase after exercise was so much more significant the more pronounced bronchospasm of effort (BE). The content of PGE after exercise rose to an approximately equal measure both in patients and in healthy subjects thereby pointing out to the relationship between the PGE increment and muscular work itself. The low level of thiol group in BA patients' blood determined by the pathological process was noticeably reduced after exercise, paralleled by an increase in the content of HP. Thus, muscular work in BA patients demonstrates high responsiveness of the systems that produce bronchoconstricting substances. It is likely that BE and its degree in BA patients may be predicted more significantly on the basis of the blood content of H, PGF2 alpha and HP rather than on the basis of the clinical and functional parameters.

[The interconnection of changes in the level of prostaglandins, catecholamines, and lipid peroxidation of membrane lipids in patients with bronchial asthma]. / O vzaimosviaziakh izmeneniia soderzhaniia prostaglandinov, katekholaminov i perekisnogo okisleniia membrannykh lipidov u bol'nykh bronkhial'noi astmoi.

Dynamics of alterations in content of prostaglandins (PG) F2 alpha and E and in the ratio PGF2 alpha/PGE was studied in blood plasma of 24 patients with chronic asthmatic bronchitis and 109 patients with bronchial asthma. Alterations in content of PGF2 alpha correlated with severity of the disease, while PGE content was similarly below the control values in all the groups examined. The ratio PGF2 alpha/PGE corresponded with the alterations in content of PGF2 alpha. Direct correlation was observed between content of adrenaline, PGF2 alpha and the rate of lipid peroxidation, whereas PGE was not related to these patterns. The correlation was completely absent under conditions of asthmatic attack.

[Relationship of the changes in catecholamines, thiol compounds, and lipid peroxidation in bronchial asthma]. / Sopriazhennost' izmenenii katekholaminov, tiolovykh soedinenii i perekisnogo okisleniia lipidov pri bronkhial'noi astme.

Dynamics of adrenaline (A), noradrenaline, SH-groups and lipid peroxidation (LP) was studied in 34 patients with chronic asthmatic bronchitis and in 132 patients with bronchial asthma. The data obtained suggest that ratios A.10/LP and SOD/SH.10 enabled to evaluate the disease compensation or transformation of asthmatic attack into asthmatic state as well as to differentiate chronic asthmatic bronchitis from bronchial asthma.

[Metabolic aspects of bronchial hyperreactivity to physical exertion in bronchial asthma]. / Metabolicheskie aspekty giperreaktivnosti bronkhov fizicheskogo usiliia pri bronkhial'noi astme.

The blood levels of stress mediators--catecholamines (adrenaline and noradrenaline), parameters characterizing the intensity of lipid peroxidation (hydroperoxides, blood antioxidant activity (from the levels of SH groups), and the content of prostaglandins F2 alpha and E (PGF2 alpha and PGE) were measured in patients with bronchial asthma and chronic asthmatic bronchitis before and after exercise. The studies have revealed that bronchial hyperreactivity to exercise is in accord with the high blood levels of catecholamines, hydroperoxides, PGF2 alpha and low content of thiol group reflecting the depression of the total antioxidant system in asthmatics. Increase of catecholamine, hydroperoxide, and PGF2 alpha levels and decrease of the total thiol group content after muscular exercise in the patients with bronchial asthma is in accord with the bronchial reactivity. Changes in the bronchoconstrictor PGF2 alpha are the most marked and measurements of its blood levels and computation of the PGF2 alpha/PGE coefficient may help assess the bronchial hyperreactivity without resorting to provocative tests.