17 research outputs found
Invariant imbedding theory of mode conversion in inhomogeneous plasmas. II. Mode conversion in cold, magnetized plasmas with perpendicular inhomogeneity
A new version of the invariant imbedding theory for the propagation of
coupled waves in inhomogeneous media is applied to the mode conversion of high
frequency electromagnetic waves into electrostatic modes in cold, magnetized
and stratified plasmas. The cases where the external magnetic field is applied
perpendicularly to the direction of inhomogeneity and the electron density
profile is linear are considered. Extensive and numerically exact results for
the mode conversion coefficients, the reflectances and the wave electric and
magnetic field profiles inside the inhomogeneous plasma are obtained. The
dependences of mode conversion phenomena on the magnitude of the external
magnetic field, the incident angle and the wave frequency are explored in
detail.Comment: 11 figures, to be published in Physics of Plasma
Хромоколоноскопия как метод улучшения эндоскопического изображения
КОЛОНОСКОПИЯЭНДОСКОПИЯхромоскопияПОЛИПЫМЕТИЛЕНОВЫЙ СИНИ
Controlling photonic structures using optical forces
The downscaling of optical systems to the micro and nano-scale results in
very compliant systems with nanogram-scale masses, which renders them
susceptible to optical forces. Here we show a specially designed resonant
structure for enabling efficient static control of the optical response with
relatively weak repulsive and attractive optical forces. Using attractive
gradient optical forces we demonstrate a static mechanical deformation of up to
20 nanometers in the resonator structure. This deformation is enough to shift
the optical resonances by roughly 80 optical linewidths.Comment: Body: 7 pages, 3 figures; Appendix: 14, 5 figure
On-chip CMOS-compatible all-optical integrator
One reason for using photonic devices is their
speed—much faster than electronic circuits—but there are many challenges in integrating the
two technologies. Ferrera et al. construct a CMOS-compatible monolithic optical waveform
integrator, a key building block for photonic circuits
The outcomes of extremely early preterm births
The paper presents the assessment of neonatal and maternal outcomes of extremely early preterm births based on retrospective analyses of 74 cases
α-Conotoxins and α-Cobratoxin Promote, while Lipoxygenase and Cyclooxygenase Inhibitors Suppress the Proliferation of Glioma C6 Cells
Among the brain tumors, glioma is the most common. In general, different biochemical mechanisms, involving nicotinic acetylcholine receptors (nAChRs) and the arachidonic acid cascade are involved in oncogenesis. Although the engagement of the latter in survival and proliferation of rat C6 glioma has been shown, there are practically no data about the presence and the role of nAChRs in C6 cells. In this work we studied the effects of nAChR antagonists, marine snail α-conotoxins and snake α-cobratoxin, on the survival and proliferation of C6 glioma cells. The effects of the lipoxygenase and cyclooxygenase inhibitors either alone or together with α-conotoxins and α-cobratoxin were studied in parallel. It was found that α-conotoxins and α-cobratoxin promoted the proliferation of C6 glioma cells, while nicotine had practically no effect at concentrations below 1 µL/mL. Nordihydroguaiaretic acid, a nonspecific lipoxygenase inhibitor, and baicalein, a 12-lipoxygenase inhibitor, exerted antiproliferative and cytotoxic effects on C6 cells. nAChR inhibitors weaken this effect after 24 h cultivation but produced no effects at longer times. Quantitative real-time polymerase chain reaction showed that mRNA for α4, α7, β2 and β4 subunits of nAChR were expressed in C6 glioma cells. This is the first indication for involvement of nAChRs in mechanisms of glioma cell proliferation
CMOS-compatible integrated optical hyper-parametric oscillator
Integrated multiple-wavelength laser sources, critical for important applications such as high-precision broadband sensing and spectroscopy, molecular fingerprinting, optical clocks and attosecond physics, have recently been demonstrated in silica and single-crystal microtoroid resonators using parametric gain. However, for applications in telecommunications and optical interconnects, analogous devices compatible with a fully integrated platform do not yet exist. Here, we report a fully integrated, CMOS-compatible, multiple-wavelength source. We achieve optical hyper-parametric oscillation in a high-index silica-glass microring resonator with a differential slope efficiency above threshold of 7.4% for a single oscillating mode, a continuous-wave threshold power as low as 54mW, and a controllable range of frequency spacing from 200GHz to more than 6THz. The low loss, design flexibility and CMOS compatibility of this device will enable the creation of multiple-wavelength sources for telecommunications, computing, sensing, metrology and other areas