Possibility of X-ray spectral diagnostics of a plasma in the tracks of fast multicharged ions

A plasma model of the relaxation of a medium within the tracks of heavy ions in condensed matter is proposed that is based on solving time-dependent radiative collisional kinetic equations with the initial condition corresponding to a medium’s state described by the classical model of multiple ionization of the target atoms by the field of fast multicharged ions. It is shown that the plasma model allows one to describe X-ray spectra recorded in the interaction of ion beams with condensed targets. An X-ray spectral method for plasma diagnostics is proposed that is based on the plasma model. The results obtained can also be used to study the initial stage of the formation of defects in solid bodies under the action of individual fast heavy ions.     

The effect of transferrin saturation on internal iron exchange

Radioiron was introduced into the intestinal lumen to evaluate absorption, injected as nonviable red cells to evaluate reticuloendothelial (RE) processing of iron, and injected as hemoglobin to evaluate hepatocyte iron processing. Redistribution of iron through the plasma was evaluated in control animals and animals whose transferrin was saturated by iron infusion. Radioiron introduced into the lumen of the gut as ferrous sulfate and as transferrin-bound iron was absorbed about half as well in iron-infused animals, and absorbed iron was localized in the liver. The similar absorption of transferrin-bound iron suggested that absorption of ferrous iron occurred via the mucosal cell and did not enter by diffusion. The decrease in absorption was associated with an increase in mucosal iron and ferritin content produced by the iron infusion. An inverse relationship (r = -0.895) was shown between mucosal ferritin iron and absorption. When iron was injected as nonviable red cells, it was deposited predominantly in reticuloendothelial cells of the spleen. Return of this radioiron to the plasma was only 6% of that in control animals. While there was some movement of iron from spleen to liver, this could be accounted for by intravascular hemolysis. Injected hemoglobin tagged with radioiron was for the most part taken up and held by the liver. Some 13% initially localized in the marrow in iron-infused animals was shown to be storage iron unavailable for hemoglobin synthesis. These studies demonstrate the hepatic trapping of absorbed iron and the inability of either RE cell or hepatocyte to release iron in the transferrin-saturated animal.     

Charge and energy spectra of fast multicharged ions in a laser plasma

In measuring the charge and energy spectra of the ions of a single-element laser plasma, in addition to thermal ions, fast multicharged ions are recorded that are accelerated by the electric field of laser radiation in the region of the critical plasma density. The charge and energy spectra of Co ions with the charge numbers z=1–3 are measured at laser intensities of q=5×10¹¹–10¹² W/cm². The energy spectra of these ions are broad and are located on the high-energy side (z _max=3, E>5.0 keV) with respect to the thermal ions (z _max=9, E<4.0 keV). The increase in q to 10¹⁴ W/cm² results in an increase in the charge number of both thermal and fast ions.     

Polarization properties of bremsstrahlung continuum and line emission of multicharged ions in a micropinch

The polarization properties of X-ray emission from micropinch discharge plasma in the spectral range corresponding to the K-lines of iron were studied experimentally. It is shown that emissions of different nature differ in the preferred orientation of polarization. The mechanisms responsible for the emission polarization are discussed.     

Formation of an anisotropic electron velocity distribution function and production of multicharged ions in the micropinch discharge plasma

Analysis of the results of polarimetric measurements of X-ray line radiation of multicharged ions in a Z-pinch discharge indicates that the formation of an anisotropic electron velocity distribution in the neck of the current channel and the generation of highly charged ions are separated in time. The generation of a fast electron beam in the longitudinal ohmic electric field in the stage of plasma compression in the neck results in the polarization of X-ray bremsstrahlung continuum. In the stage of expansion of the hot dense micropinch plasma, the radial electric field prevails, due to which X-ray line radiation of multicharged ions becomes linearly polarized.     

Determination of the electron density and electric field in the plasma of a low-pressure microwave electrode discharge in hydrogen from the measured spectral line intensities

The parameters of the plasma of a microwave electrode discharge in hydrogen at pressures of 1–8 torr and incident powers of 20–80 W are measured by the so-called “relative intensity” method. The method allows one to determine the electron density and electric field in plasma by measuring the relative intensities of the H_α, H_β, and 763.5-nm Ar line emission and calculating the electron-impact rate constants from the homogeneous Boltzmann equation. The measurements show that there are regions in the discharge where the electron density is higher (a bright electrode sheath) and lower (a spherical region) than the critical density for the frequency 2.45 GHz (n_cr～7×10¹⁰ cm^?3). Inside the spherical region, the electric field varies slightly over the radius and the electron density increases as the discharge boundary is approached. The observed discharge structure can be attributed to the presence of a self-sustained discharge zone (electrode sheath); a non-self-sustained discharge zone (spherical region); and a decaying plasma region, which is separated from the active discharge zone by an electric double layer.     

Influence of resonant charge exchange on the viscosity of partially ionized plasma in a magnetic field

The influence of resonant charge exchange for ion-atom interaction on the viscosity of partially ionized plasma embedded in the magnetic field is investigated. The general system of equations used to derive the viscosity coefficients for an arbitrary plasma component in the 21-moment approximation of Grad’s method is presented. The expressions for the coefficients of total and partial viscosities of a multicomponent partially ionized plasma in the magnetic field are obtained. As an example, the coefficients of the parallel and transverse viscosities for the ionic and neutral components of the partially ionized hydrogen plasma are calculated. It is shown that the account for resonant charge exchange can lead to a substantial change of the parallel and transverse viscosity of the plasma components in the region of low degrees of ionization on the order of 0.1.     

A method for calculating the effective charge of ions decelerated in a hot dense plasma

A method for calculating the effective charge of fast ions decelerated in a hot dense plasma is proposed. The method is based on the known experimental dependence of the effective charge of an ion decelerated in cold matter on its velocity. The ion velocity in this dependence is replaced with the velocity of an ion relative to plasma electrons, averaged over the Fermi-Dirac distribution. Using results of numerical calculations performed in a wide range of plasma parameters (from a Maxwellian plasma to a fully degenerate one), a scale-invariant representation of the effective charge of a decelerating ion as a function of its initial velocity and the plasma temperature and density is obtained. An analytical formula fitting the calculated results to within 5% is derived. The obtained dependences of the effective charge are incorporated in the model describing deceleration of fast ions in plasma. Using this model, the stopping powers of krypton and lead ions in a relatively cold rarefied gas-discharge plasma and hot ICF plasma are calculated. The results of calculations are shown to agree satisfactorily with available experimental data.     

Diffusion of charged ions in mucus gel: effect of net charge

The interposition of a neutral starch gel greatly retarded bulk ionic movement by free flow. A mucus (charged) gel preparation of identical concentration and thickness further retarded ionic diffusion. The findings suggest that the charges in the mucus matrix may exert an ionic exclusion effect (Donnan Exclusion), thus retarding other ionic diffusion. We speculate that a mucus layer may physiologically behave as an ion exchange gel column and modify the traffic of charged ions through it.     

Acceleration of heavy multicharged ions in the interaction of a subrelativistic femtosecond laser pulse with a melted metal surface

Results are presented from experimental studies of ion acceleration under the action of femtosecond laser pulses with an intensity of 10¹⁷ W/cm², incident onto the free surfaces of melted gallium and indium. The effect of the polarization direction of a linearly polarized laser pulse and the amplitude of a short prepulse, which precedes the main pulse by several nanoseconds, on the parameters of accelerated ions is investigated. It is found that, even for such a moderate laser intensity, the characteristic velocity of fast ions ejected along the reflected beam is a factor of 1.5 higher than that of ions ejected along the normal to the target surface. It is shown that, as the prepulse energy increases, the hard X-ray yield and the mean energy of hot electrons increase substantially, whereas the velocity of both fast and slow ions decreases appreciably regard-less of laser polarization.     

Structure of the fronts of strong collisional shock waves in an ideal two-temperature electron-ion plasma with ions of arbitrary charge

Solutions in the form of plane running waves are investigated numerically in the framework of a two-temperature hydrodynamic model of a fully ionized ideal plasma with ions of arbitrary charge number Z₀. Most simulations were carried out for simple boundary conditions corresponding to a cold immobile plasma at the front of a running wave. All the solutions obtained have a discontinuity in the form of an isoelectronic-thermal jump, whose parameters relax to their steady-state values in the course of calculation. The problem of finding numerical solutions in which all the quantities at infinity take on finite (equilibrium) values actually reduces to the problem of the front structure of a strong shock wave. For a plasma with singly changed ions (Z₀ = 1), numerical solutions were found to coincide with the previously known solution. For a plasma with arbitrarily charged ions (Z₀ > 1), numerical solutions were obtained for the first time on the basis of justified formulas for the electron thermal conductivity.     

FTIR spectral signature of the effect of cardiotonic steroids with antitumoral properties on a prostate cancer cell line

We show in the present work that the infrared (IR) spectrum of human PC-3 prostate cancer cells exposed to anticancer drugs could offer a unique opportunity to get a fingerprint of all the major biochemical components (DNA, RNA, proteins, lipids, etc.) present in the cells and to identify with high sensitivity the signature of the metabolic changes induced by anticancer drugs.We investigated here the FTIR-related signatures of the effect of 4 structurally-related cardiotonic steroids (CS), i.e. ouabain, 19-hydroxy-2″-oxovoruscharin, hellebrin and 19-hydroxy-hellebrin on PC-3 cancer cells incubated between 0 and 36 h in the absence (control) or the presence of the CS. For each molecule a single spectral signature described the largest part of the time dependent modifications with a possible very minor second component. The spectral signatures characterizing the effects of each of the four CS were unique but very similar when compared to the signature of the effect of an intercalating anticancer drug, i.e. doxorubicin, selected as a positive reference compound in our study, suggesting a fully distinct set of cellular perturbations. The current study thus illustrates that Fourier Transform Infrared (FTIR) analyses can be used to identify, among the perturbations induced on a given cancer cell line, the features common to a group of anticancer compounds as well as features specific to every single drug.     

The effect of spectral light deprivation on the spectral sensitivity of the honey bee

Summary The spectral sensitivity of spontaneous phototactic behavior was tested in short wavelength deprived bees and in control bees kept outdoors. Tests were performed with a y-maze with one branch illuminated, the other dark. The relative sensitivities for the control group were: green to blue to UV = 10.272.14. Short wavelength deprived bees show a distinct decrease in their sensitivity to short wavelengths. The relation green to blue to UV here was 10.220.27. Forager bees from outdooors, short wavelength deprived for 10 days, showed a relation of green to blue to UV of 10.261.04. Electrophysiological investigation of the compound eye using electroretinogram recordings showed no difference between deprived and control animals.     

The effect of the pH and phosphate ions on the precipitate formation reaction of sodium ions with pyroantimonate

Summary The effect of phosphate ions and the pH of the solution on the precipitation of Na-pyroantimonate was studied by a quantitative method. The presence of phosphate ions has an inhibitory effect on the formation of Na-pyroantimonate precipitate. The inhibiting effect decreases with the increasing concentration of hydroxyl ions. In the absence of phosphate ions at pH 9.5 Na⁺-ions precipitate completely. The inhibiting effect is explained by a complex formation reaction of the phosphate ions with the antimony (V) ions.