Anomalous plasma heating by an intense laser beam

Heating of laser produced plasmas by an instability is investigated. For intense laser beams anomalous absorption is found. A comparison is made with the experiment.

Low-frequency degenerate surface modes of an electron-hole plasma

The computations of Flahive and Quinn1 of the dispersion curves of low frequency degenerate surface (DS) modes propagating along the magnetic field in an electron-hole plasma are extended to higher values of the wavenumber. We find that beyond a certain value of the wavenumber the DS mode re-enters the allowed region of surface wave propagation and tends to an asymptotic frequency ωR (<ωLH). These low frequency resonances of an electron-hole plasma are discussed with reference to the experimental observations.

Polyvanadate-stimulated NADH oxidation by plasma membranes-The need for a mixture of deca and meta forms of vanadate

Polyvanadate solutions obtained by extracting vanadium pentoxide with dilute alkali over a period of several hours contained increasing amounts of decavanadate as characterized by NMR and ir spectra. Those solutions having a metavanadate:decavanadate ratio in the range of 1-5 showed maximum stimulation of NADH oxidation by rat liver plasma membranes. Reduction of decavanadate, but not metavanadate, was obtained only in the presence of the plasma membrane enzyme system. High simulation of activity of NADH oxidation was obtained with a mixture of the two forms of vanadate and this further increased on lowering the pH. Addition of increasing concentrations of decavanadate to metavanadate and vice versa increased the stimulatory activity, reaching a maximum when the metavanadate:decavanadate ratio was in the range of 1-5. Increased stimulatory activity can also be obtained by reaching these ratios by conversion of decavanadate to metavanadate by alkaline phosphate degradation, and of metavanadate to decavanadate by acidification. These studies show for the first time that both deca and meta forms of vanadate present in polyvanadate solutions are needed for maximum activity of NADH oxidation.

Indian Ocean response to anomalous conditions in 2006

[1] The equatorial Indian Ocean (EIO) exhibited anomalous conditions characteristic of an Indian Ocean dipole (IOD) during 2006. The eastern EIO had cold sea surface temperature anomalies (SSTA), lower sea level, shallow thermocline and higher chlorophyll than normal. The anomalies in the east, restricted to the south of the equator, were highest off Sumatra. The western pole of the IOD was marked by warm SSTA and deeper thermocline with maxima on either side of the equator. An ocean general circulation model of the Indian Ocean forced by QuikSCAT winds reproduces the IOD of 2006 remarkably well. The switch over to cooling in the east and warming in the west happened during May and July respectively. In the east, airsea heat flux initiated cold SSTA in the model which were sustained later by oceanic processes. In the west, surface heat fluxes and horizontal advection caused warm SSTA and contribution by the latter decreased after August. Citation: Vinayachandran, P. N., J. Kurian, and C. P. Neema (2007), Indian Ocean response to anomalous conditions in 2006, Geophys. Res. Lett., 34, L15602, doi:10.1029/2007GL030194.

Indian Ocean response to anomalous conditions in 2006

The equatorial Indian Ocean (EIO) exhibited anomalous conditions characteristic of an Indian Ocean dipole (IOD) during 2006. The eastern EIO had cold sea surface temperature anomalies (SSTA), lower sea level, shallow thermocline and higher chlorophyll than normal. The anomalies in the east, restricted to the south of the equator, were highest off Sumatra. The western pole of the IOD was marked by warm SSTA and deeper thermocline with maxima on either side of the equator. An ocean general circulation model of the Indian Ocean forced by QuikSCAT winds reproduces the IOD of 2006 remarkably well. The switch over to cooling in the east and warming in the west happened during May and July respectively. In the east, air-sea heat flux initiated cold SSTA in the model which were sustained later by oceanic processes. In the west, surface heat fluxes and horizontal advection caused warm SSTA and contribution by the latter decreased after August.

Physicochemical studies on the gelation of hen egg yolk; separation of gelling protein components from yolk plasma

A study of the component(s) in egg yolk responsible for gelation of yolk on freezing and thawing has shown that granule-free yolk plasma, obtained by high-speed centrifugation of yolk, has the capacity to gel. As with the whole yolk, gelation of yolk plasma on freezing and thawing could be inhibited by additives such as sugars, sodium chloride, proteolytic enzymes, and phospholipase-A. Phospholipase-C, which induces gelation of whole yolk at room temperature, has a similar effect on yolk plasma. Yolk plasma has been separated into aggregating (gelling) and soluble fractions by delipidation, using formic acid. Each of these fractions consists of three or four protein components, as observed by gel filtration, ultracentrifugation, and agar electrophoresis. The proteins are glycoproteins and contain bound hexoses, hexosamine, and sialic acid. The gelation of yolk has been attributed to the interactions between protein molecules following disruption of lipid-protein bonds.

Effect of cold exposure on the metabolism of ubiquinone in the rat

1. Accumulation of ubiquinone in the livers of rats exposed to a cold environment was shown to be due to both decreased catabolism during the entire experimental period and increased synthesis during an intermediate stage (10–20 days). 2. The increased endogenous synthesis in the cold-exposed rats was eliminated when ubiquinone accumulated in the liver after exposure for 40 days (coinciding with cclimatization), or by absorption of the exogenous dietary supply, possibly by the mechanism of end-product regulation.

Two-stream instability in plasma

The problem of two-stream instability in plasma is studied by specifying the importance of initial magnetic field associated with the motion of the charged particles and the boundary effects. In Part I the accurate initial steady state is studied when the streams of electrons and ions move with different uniform speeds in plasmas with plane and cylindrical geometry. In Part II, in order to show the effects of finiteness and inhomogeneity of the system, small transverse plasma oscillations are studied in the case of plane plasmas. The role of plasma-sheath oscillations at the boundaries is found to be very important in driving the instabilities associated with the electromagnetic modes. The numerical estimates of the growth rates of the instability are given for the specific case of the physical data in discharge tubes.

Chemical modification of sheep plasma glycoprotein

Glycoprotein isolated from sheep plasma was chemically modified, and the effect of chemical modification on biological activities and immunological cross reactions has been studied. The removal of sialic acid resulted in a change in the “overall conformation” of the glycoprotein as evidenced by a decrease in viscosity of the glycoprotein solution and an increased susceptibility of the glycoprotein to proteolytic enzymes. Sialic acid-free glycoprotein no longer inhibited the tryptic activity or prolonged the clotting time of plasma. However, it could react with the antiserum to sheep plasma glycoprotein. The periodate oxidation of sheep plasma glycoprotein resulted in a complete loss of inhibition of trypsin activity, prolongation of plasma clotting time, and the ability to cross-react with the rabbit antiserum. The significance of periodate oxidation in relation to the possible sequence of sugars in the carbohydrate prosthetic group in the glycoprotein is discussed. Iodination and heating in buffers of acid and alkaline pH values of sheep plasma glycoprotein resulted in complete loss of trypsin activity and ability to prolong plasma clotting time. Iodination of the glycoprotein did not affect the immunological cross-reactivity.

Physicochemical studies on the gelation of hen's egg yolk: Delipidation of yolk plasma by treatment with phospholipase-C and extraction with solvents

A method for the delipidation of egg yolk plasma using phospholipase-C, n-heptane, and 1-butanol has been described. An aggregating protein fraction and a soluble protein fraction were separated by the action of phospholipase-C. The aggregating protein fraction freed of most of the lipids by treatment with n-heptane and 1-butanol was shown to be the apolipoproteins of yolk plasma, whereas the soluble proteins were identified as the livetins. Carbohydrate and the N-terminal amino acid analysis of these protein fractions are reported. A comparison of these protein fractions with the corresponding fractions obtained by formic acid delipidation of yolk plasma has been made. The gelation of yolk plasma by the action of phospholipase-C has been interpreted as an aggregation of lipoproteins caused by ionic interactions. The role of lecithin in maintaining the structural integrity of lipoproteins has been discussed.

Stability of a cylindrical plasma in the presence of a monotonic field-II

The stability of an incompressible inviscid, perfectly conducting cylindrical plasma against azimuthal disturbances in the presence of a monotonic decreasing magnetic field having a constant pitch is discussed by using energy principle. The results obtained by this principle are compared for m = 1 mode (which is a dangerous mode in which there is a lateral shift of the entire column) with that obtained by normal mode analysis. It is found that m = 1 mode is always unstable. Further, an axial line current, external axial field and the surface tension tend to stabilise m ≠ modes.

Harmonic and anharmonic oscillations of a cylindrical plasma in the presence of a uniform axial magnetic field and a steady axial current

In the present note we have studied the harmonic and anharmonic oscillations of cylindrical plasma using Lagrangian formalism. In order to study the harmonic oscillations, the equations are linearized and the resulting equation for the displacement has been numerically solved. For situations present in thermonuclear reactors, the presence of axial magnetic field is found necessary to make the periods of oscillation to become comparable with the time required for the thermonuclear reactions to set in. A detailed analysis of the anharmonic oscillations reveals that the significant interaction is between the first and the second mode. The fundamental period of anharmonic oscillation is more than the corresponding period of harmonic oscillations by 9·2%. Graphs have been drawn for the amplitudes of relative variations in density and magnetic field and of the time-varying part of anharmonic oscillation.

Electron energy equation for an atomic radiating plasma

The electron-energy equation for an atomic radiating plasma is considered in this work. Using the atomic model of Bates, Kingston and McWhirter, the radiation loss-term valid for all optical thicknesses is obtained. A study of the energy gained by electrons in inelastic collisions shows that the radiation loss term can be neglected only for rapidly-decaying or fast-growing plasmas. Emission from optically thin plasmas is considered next and an exact expression is given for the total radiation loss in a recombination continuum. A derivation of the Kramers-Unsöld approximation is presented and the error involved in estimating the total emitted recombination radiation by this approximation is shown to be small.