Laser Printing of Gel Microdrops with Living Cells and Microorganisms

We report the results of experiments on laser printing (wavelength λ=1064 nm) with gel microdrops acting as carriers of living microbial and cellular objects. The dynamics of transport processes with the help of high-speed optical video was studied, which allows to determine characteristics of the formed gel jets and to optimize the operating mode of the laser. It is shown that laser pulses of 4 to 20 ns duration and energy E ≤ 20 μJ should be used to minimize the negative effect on living systems. The results can be used to optimize the technologies of cellular printing and laser engineering of microbial systems (LEMS). LEMS technology is used to isolate hard-cultivated and non-cultivated by classical methods of microorganisms that can act as producers of new biologically active substances and antibiotics. Keywords: laser printing, gel, microdrop, living cell, microbia

Magnetic and spectral properties of multi-sublattice oxides SrY2O4:Er3+ and SrEr2O4

SrEr2O4 is a geometrically frustrated magnet which demonstrates rather unusual properties at low temperatures including a coexistence of long- and short-range magnetic order, characterized by two different propagation vectors. In the present work, the effects of crystal fields (CF) in this compound containing four magnetically inequivalent erbium sublattices are investigated experimentally and theoretically. We combine the measurements of the CF levels of the Er3+ ions made on a powder sample of SrEr2O4 using neutron spectroscopy with site-selective optical and electron paramagnetic resonance measurements performed on single crystal samples of the lightly Er-doped nonmagnetic analogue, SrY2O4. Two sets of CF parameters corresponding to the Er3+ ions at the crystallographically inequivalent lattice sites are derived which fit all the available experimental data well, including the magnetization and dc susceptibility data for both lightly doped and concentrated samples.Comment: 14 pages, 9 figure

Diagnostics of artificial ionospheric irregularities using short sounding radio paths

In this work, we consider the possibilities of diagnostics of artificial ionospheric irregularities with the transverse size l⊥ ≈ 50-200 m, which are excited in the Earth's ionosphere by highpower short-wave radio-frequency radiation from the "Sura" facility using the method of vertical sounding of the ionosphere by the ionosonde located near the heating facility. Some results of the performed studies showing the features of such a diagnostics are presented. © 2012 Springer Science+Business Media, Inc

Coupled Dynamics of Spin Qubits in Optical Dipole Microtraps: Application to the Error Analysis of a Rydberg-Blockade Gate

Single atoms in dipole microtraps or optical tweezers have recently become a promising platform for quantum computing and simulation. Here we report a detailed theoretical analysis of the physics underlying an implementation of a Rydberg two-qubit gate in such a system—a cornerstone protocol in quantum computing with single atoms. We focus on a blockade-type entangling gate and consider various decoherence processes limiting its performance in a real system. We provide numerical estimates for the limits on fidelity of the maximally entangled states and predict the full process matrix corresponding to the noisy two-qubit gate. We consider different excitation geometries and show certain advantages for the gate realization with linearly polarized driving beams. Our methods and results may find implementation in numerical models for simulation and optimization of neutral atom based quantum processors

Coronavirus disease 2019 (COVID-19): NETosis-associated mechanisms of progression and prospects for therapy regulating the formation of neutrophil extracellular traps (NETs)

Infectious disease COVID-19 caused by the SARS-CoV-2 coronavirus is characterized by high contagiousness, complexity of pathogenesis and unpredictability of the clinical course. In severe cases, which are especially susceptible to men, the elderly and people with underlying medical conditions such as obesity, diabetes, hypertension, cardiovascular and chronic respiratory diseases, the infection leads to respiratory failure and death due to the development of an extensive inflammatory reaction. As a result of many studies, it has been established that one of the leading causes of the severe course and death of patients with COVID-19 is the development of coagulopathy, that is, increased thrombus formation in small vessels due to excessive activity of neutrophils, which form the so-called neutrophil extracellular traps (NETs). Although NETs play a useful role in protecting their host from pathogens, their overgrowth can trigger a cascade of adverse reactions including: the production of antibodies against the host’s DNA (autoimmunization); damage to surrounding tissue; or the occurrence of thromboembolic complications. Therefore, extracellular neutrophil traps and their markers have been identified as targets for new therapeutic strategies aimed at reducing the severity of COVID-19 disease and/or mortality. This article describes the structure of NETs, as well as analyzes the molecular mechanisms that contribute to their overgeneration. In addition, the prospects for COVID-19 therapy aimed at regulating the formation of extracellular traps by creating drugs both limiting the production of NET structures and dissolving their excess amounts in the body of patients are discussed