Khlebtsov N.,Chernyshevsky Saratov State University |
Dykman L.,Russian Academy of Sciences
Chemical Society Reviews | Year: 2011
Recent advances in wet chemical synthesis and biomolecular functionalization of gold nanoparticles have led to a dramatic expansion of their potential biomedical applications, including biosensorics, bioimaging, photothermal therapy, and targeted drug delivery. As the range of gold nanoparticle types and their applications continues to increase, human safety concerns are gaining attention, which makes it necessary to better understand the potential toxicity hazards of these novel materials. Whereas about 80 reports on the in vivo biodistribution and in vitro cell toxicity of gold nanoparticles are available in the literature, there is lack of correlation between both fields and there is no clear understanding of intrinsic nanoparticle effects. At present, the major obstacle is the significant discrepancy in experimental conditions under which biodistribution and toxicity effects have been evaluated. This critical review presents a detailed analysis of data on the in vitro and in vivo biodistribution and toxicity of most popular gold nanoparticles, including atomic clusters and colloidal particles of diameters from 1 to 200 nm, gold nanoshells, nanorods, and nanowires. Emphasis is placed on the systematization of data over particle types and parameters, particle surface functionalization, animal and cell models, organs examined, doses applied, the type of particle administration and the time of examination, assays for evaluating gold particle toxicity, and methods for determining the gold concentration in organs and distribution of particles over cells. On the basis of a critical analysis of data, we arrive at some general conclusions on key nanoparticle parameters, methods of particle surface modification, and doses administered that determine the type and kinetics of biodistribution and toxicity at cellular and organismal levels (197 references). © 2011 The Royal Society of Chemistry.
Leinson L.B.,Russian Academy of Sciences
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2015
In a simple model it is demonstrated that the neutron star surface temperature evolution is sensitive to the phase state of the triplet superfluid condensate. A multicomponent triplet pairing of superfluid neutrons in the core of a neutron star with participation of several magnetic quantum numbers leads to neutrino energy losses exceeding the losses from the unicomponent pairing. A phase transition of the neutron condensate into the multicomponent state triggers more rapid cooling of superfluid core in neutron stars. This makes it possible to simulate an anomalously rapid cooling of neutron stars within the minimal cooling paradigm without employing any exotic scenarios suggested earlier for rapid cooling of isolated neutron star in Cassiopeia A. © 2014 The Author.
D'yachkov L.G.,Russian Academy of Sciences
Technical Physics Letters | Year: 2015
The classical Coulomb cluster in a cylindrically symmetric harmonic trap is treated in the approximation of a homogeneous volume distribution of particles. Analytical solutions for the cluster size and potential energy are obtained, which are only valid for clusters with a large number of particles. The influence of a possible inhomogeneity is determined, and it is established that this factor weakly influences the potential energy. The expression for the potential energy is extended to smaller clusters by introducing a correction factor derived through approximation of the results of numerical calculations. © 2015, Pleiades Publishing, Ltd.
Dubovskiy I.M.,Russian Academy of Sciences
Proceedings. Biological sciences / The Royal Society | Year: 2013
A 'dark morph' melanic strain of the greater wax moth, Galleria mellonella, was studied for its atypical, heightened resistance to infection with the entomopathogenic fungus, Beauveria bassiana. We show that these insects exhibit multiple intraspecific immunity and physiological traits that distinguish them from a non-melanic, fungus-susceptible morph. The melanic and non-melanic morphs were geographical variants that had evolved different, independent defence strategies. Melanic morphs exhibit a thickened cuticle, higher basal expression of immunity- and stress-management-related genes, higher numbers of circulating haemocytes, upregulated cuticle phenoloxidase (PO) activity concomitant with conidial invasion, and an enhanced capacity to encapsulate fungal particles. These insects prioritize specific augmentations to those frontline defences that are most likely to encounter invading pathogens or to sustain damage. Other immune responses that target late-stage infection, such as haemolymph lysozyme and PO activities, do not contribute to fungal tolerance. The net effect is increased larval survival times, retarded cuticular fungal penetration and a lower propensity to develop haemolymph infections when challenged naturally (topically) and by injection. In the absence of fungal infection, however, the heavy defence investments made by melanic insects result in a lower biomass, decreased longevity and lower fecundity in comparison with their non-melanic counterparts. Although melanism is clearly correlated with increased fungal resistance, the costly mechanisms enabling this protective trait constitute more than just a colour change.
Pavlov A.V.,Russian Academy of Sciences
Surveys in Geophysics | Year: 2014
The current state of knowledge of the D-region ion photochemistry is reviewed. Equations determining production rates of electrons and positive ions by photoionization of atmospheric neutral species are presented and briefly discussed. Considerable attention is given to the progress in the chemistry of O+(4S), O+(2D), O+(2P), N+, N2 +, O2 +, NO+, N4 +, O4 +, NO+(N2), NO+(CO2), NO+(CO2)2, NO+(H2O)n for n = 1-3, NO+(H2O)(N2), NO+(H2O)2(N2), NO+(H2O)(CO2), NO+(H2O)2(CO2), O2 +(H2O), H3O+(OH), H+(H2O)n for n = 1-8, O-, O2 -, O3 -, O4 -, OH-, CO3 -, CO4 -, NO2 -, NO3 -, ONOO-, Cl-, Cl-(H2O), Cl-(CO2), HCO3 -, CO3 -(H2O), CO3 -(H2O)2, NO3 -(H2O), NO3 -(H2O)2, OH-(H2O), and OH-(H2O)2 ions. The analysis of the D-region rocket ion mass spectrometer measurements shows that, among these ions, O2 +, NO+, NO+(H2O), and H+(H2O)n for n = 1-7 can make the main contribution to the total positive ion number density, and O-, O2 -, Cl-, OH-(H2O), CO3 -, HCO3 -, NO3 -, ONOO-, CO4 -, NO3 -(H2O), NO3 -(H2O)2, and 35Cl-(CO2) ions can be responsible for the main contribution to the total negative ion number density. Photodetachment of electrons from O-, Cl-, O2 -, O3 -, OH-, NO2 -, and NO3 -, dissociative electron photodetachment of O4 - and OH-(H2O), and photodissociation of O3 -, O4 -, CO3 -, CO4 -, ONOO-, HCO3 -, CO3 -(H2O), NO3 -(H2O), O2 +(H2O), O4 +, N4 +, NO+(H2O), NO+(H2O)2, H+(H2O)n for n = 2-4, NO+(N2), and NO+(CO2) are studied, and the photodetachment and photodissociation rate coefficients are calculated using the current state of knowledge on the cross sections of these processes and fluxes of solar radiation. © 2013 Springer Science+Business Media Dordrecht.