Spontaneous decay of excited atomic states near a carbon nanotube

Spontaneous decay process of an excited atom placed inside or outside (near the surface) a carbon nanotube is analyzed. Calculations have been performed for various achiral nanotubes. The effect of the nanotube surface has been demonstrated to dramatically increase the atomic spontaneous decay rate -- by 6 to 7 orders of magnitude compared with that of the same atom in vacuum. Such an increase is associated with the nonradiative decay via surface excitations in the nanotube.Comment: 8 pages, 3 figure

Microscopic theory of quantum dot interactions with quantum light: local field effect

A theory of both linear and nonlinear electromagnetic response of a single QD exposed to quantum light, accounting the depolarization induced local--field has been developed. Based on the microscopic Hamiltonian accounting for the electron--hole exchange interaction, an effective two--body Hamiltonian has been derived and expressed in terms of the incident electric field, with a separate term describing the QD depolarization. The quantum equations of motion have been formulated and solved with the Hamiltonian for various types of the QD excitation, such as Fock qubit, coherent fields, vacuum state of electromagnetic field and light with arbitrary photonic state distribution. For a QD exposed to coherent light, we predict the appearance of two oscillatory regimes in the Rabi effect separated by the bifurcation. In the first regime, the standard collapse--revivals phenomenon do not reveal itself and the QD population inversion is found to be negative, while in the second one, the collapse--revivals picture is found to be strongly distorted as compared with that predicted by the standard Jaynes-Cummings model. %The model developed can easily be extended to %%electromagnetic excitation. For the case of QD interaction with arbitrary quantum light state in the linear regime, it has been shown that the local field induce a fine structure of the absorbtion spectrum. Instead of a single line with frequency corresponding to which the exciton transition frequency, a duplet is appeared with one component shifted by the amount of the local field coupling parameter. It has been demonstrated the strong light--mater coupling regime arises in the weak-field limit. A physical interpretation of the predicted effects has been proposed.Comment: 14 pages, 7 figure

Spontaneous decay of an emitter's excited state near a finite-length metallic carbon nanotube

The spontaneous decay of an excited state of an emitter placed in the vicinity of a metallic single-wall carbon nanotube (SWNT) was examined theoretically. The emitter-SWNT coupling strongly depends on the position of the emitter relative to the SWNT, the length of the SWNT, the dipole transition frequency and the orientation of the emitter. In the high-frequency regime, dips in the spectrum of the spontaneous decay rate exist at the resonance frequencies in the spectrum of the SWNT conductivity. In the intermediate-frequency regime, the SWNT conductivity is very low, and the spontaneous decay rate is practically unaffected by the SWNT. In the low-frequency regime, the spectrum of the spontaneous decay rate contains resonances at the antennas resonance frequencies for surface-wave propagation in the SWNT. Enhancement of both the total and radiative spontaneous decay rates by several orders in magnitude is predicted at these resonance frequencies. The strong emitter-field coupling is achieved, in spite of the low Q factor of the antenna resonances, due to the very high magnitude of the electromagnetic field in the near-field zone. The vacuum Rabi oscillations of the population of the excited emitter state are exhibited when the emitter is coupled to an antenna resonance of the SWNT.Comment: 8 pages, 6 figure

Analysis of Multiwalled Carbon Nanotubes as Waveguides and Antennas in the Infrared and the Visible Regimes

The propagation of azimuthally symmetric guided waves in multiwalled carbon nanotubes (MWCNTs) was analyzed theoretically in the mid-infrared and the visible regimes. The MWCNTs were modeled as ensembles of concentric, cylindrical, conducting shells. Slightly attenuated guided waves and antenna resonances due to the edge effect exist for not-too-thick MWCNTs in the far- and mid-infrared regimes. Interband transitions hinder the propagation of guided waves and have a deleterious effect on the performance of a finite-length MWCNT as an antenna. Propagation of surface-plasmon waves along an MWCNT with a gold core was also analyzed. In the near-infrared and the visible regimes, the shells behave effectively as lossy dielectrics suppressing surface-plasmon-wave propagation along the gold core.Comment: 13 pages, 8 figure

Effects of antioxidant bienzyme conjugate in rats with endotoxin shock model after different regime of administration

Cardiovascular injuries have been going along with oxidative stress as usually. The antioxidant enzymes (as superoxide dismutase /SOD/ and catalase /CAT/) are significant potential agents for therapeutic aim but they demanded the improvement of their biopharmaceutical properties. For this goal the bienzyme covalent conjugate was obtained by binding SOD with CAT via endothelial glycocalyx glycosaminoglycan – chondroitin sulfate (SOD-CHS-CAT). The SOD-CHS-CAT conjugate had prophylaxis and preventive actions after intravenous administration of hydrogen peroxide in rabbits and rats. It should be noted the oxidative stress accompanies for development of endotoxin shock. There is the model of septic shock of animals due to administration of bacterial lypopolysaccharide (LPS, from Salmonella enterica serotype Typhimurium) them as provoking infectious agent. The therapeutic effect of bienzyme SOD-CHS-CAT conjugate has special research interest associated with activity of conjugate after preventive and medicative administration (i.e. before and after LPS administration, respectively). The effect of bienzyme conjugate administered in medicative regime had increased the survival of rats for endotoxin shock. It was the expressive efficacy of medicinal employment of SOD-CHS-CAT conjugate. The obtained results have been grounded the need of experimental evaluation in respect to efficacy of per oral prophylaxis administration of SOD-CHS-CAT conjugate on the endotoxin model injury in rats induced by LPS bolus. The intravenous bolus administration of LPS in rats has been induced the endotoxin shock development with arterial pressure (AP) decrease, heart rate (HR) increase, impairment of condition even before the lethal termination. The AP decrease was restored faster in experimental group; the alterations of HR were similar in both groups. The survival index (73 % in experimental and 63 % in control groups) for twenty-four hours was similar. Higher survival index (95 % in experimental and 75 % in control groups, for five hours) was marked in experimental group emphasizing the action celerity of SOD-CHS-CAT conjugate in vivo. The SOD-CHS-CAT conjugate was active during cytokine phase of endotoxin injury and distant damage stages. Moreover, the level of NO in lever, lung, kidney, heart was enhanced during endotoxin shock progress and there were not significant alterations of NO level after bienzyme conjugate administration intravenously. The changes of urea and creatinine in blood samples have been evidenced the protective action of bienzyme conjugate in respect to kidney function. Diversity of other index alterations have been hampered the forming agreed conclusions about state of other organs. Taken together these date indicated (on the base of survival increase of rats with SOD-CHS-CAT conjugate for endotoxin shock) the other protective effects of this conjugate (besides NO preservation) and importance of its action mechanism investigation on animal model with continuous development of injury and involvement of other vasoactive agents (NO-independent progress of therapeutic effect). This research was supported in part by RFBR grant 15-04-03584 and Ministry of Health Care of Russian Federation

Legal basis for medical examination of persons getting married under the laws of Russia and some foreign countries

The article discusses the problems of legal regulation of some aspects of marriage, namely the medical examination of future spouses. Considering that the issues of this requirement are both recommendatory (dispositive) and mandatory (imperative) in the countries, the authors, using the legislation of the Russian Federation and other countries as an example, analyzed the regulatory regulation of this institution and made recommendations on the ways of such problem solutio

Singular Modes of the Electromagnetic Field

We show that the mode corresponding to the point of essential spectrum of the electromagnetic scattering operator is a vector-valued distribution representing the square root of the three-dimensional Dirac's delta function. An explicit expression for this singular mode in terms of the Weyl sequence is provided and analyzed. An essential resonance thus leads to a perfect localization (confinement) of the electromagnetic field, which in practice, however, may result in complete absorption.Comment: 14 pages, no figure

Spontaneous emission of an atom placed near a nanobelt of elliptical cross-section

Spontaneous emission of an atom (molecule) placed near a nanocylinder of elliptical cross-section of an arbitrary composition is studied. The analytical expressions have been obtained for the radiative and nonradiative channels of spontaneous decay and investigated in details.Comment: 35 pages, 11 figure

Russian University Teachers’ Ethical Culture Regulation

Based on a review of publications of Russian and foreign researchers, the authors highlight the most significant topics on the deontology of university life. The article presents the results of an analysis of the texts of ethical codes of some leading universities in Russia (National Research University Higher School of Economics, Moscow State University, St. Petersburg State University, Kazan Federal University, Ural Federal University), as well as the results of an online survey (N = 297) of teachers of these universities. The survey was conducted to study the attitude of the teaching staff towards the tools for standardizing the moral culture of universities and the implementation of the values enshrined in the ethical standards of universities and ideals of academic community. Conclusions are made about the ethical attitudes of teachers and the effectiveness of moral regulation, as well as proposals for improving the ethical codes of universities are made

Protective action of bienzyme conjugate of antioxidant biocatalysts in vivo

Endotoxin shock in rats led to intravenous bolus of bacterial lipopolysaccharide (LPS) was accompanied by oxidative stress and increase of NO level in livers, lungs, kidneys, hearts of animals. The intravenous administration of bienzyme superoxide dismutase - chondroitin sulphate - catalase conjugate (SOD-CHS-CAT) showed its anti-endotoxemia action in rats at preventive (before initiation of injury) and therapeutic (after start of injury) application during cytokine phase of injury and influence on further stages of the damage. The injection of antioxidant SOD-CHS-CAT conjugate in a therapeutic regime did not demonstrate significant alterations of No level in livers, lungs, kidneys, hearts of rats (as compared to indices of the rat group with LpS action only) and displayed protective action on the kidney function by altered urea and creatinine in blood. The therapeutic effect of SOD-CHS-CAT was demonstrated by increase in organism viability. The effects of intravenous injection of SOD-CHS-CAT in a rat model of endotoxin shock showed a variety in the activity of this conjugate in addition to prevention of NO conversion in peroxynitrite upon interaction with O2 superoxide radical. The results of accelerated normalization of arterial blood pressure and heart rate, a significant decrease in rat lethality because of using SOD-CHS-CAT conjugate indicate the importance of the determination of action mechanism of the cardiovascular injury models associated with other vasoactive agents besides NO. The further research of vascular damage pathogenesis and evaluation of its role in oxidative stress (time and place) are of paramount importance