Survival of microorganisms during two-year exposure in outer space near the ISS.

Results of an experiment named "Test" on survival and variability of microorganisms in open space near the International Space Station are presented. It was found after two-years exposure, spore-forming bacteria of the species Bacillus subtilis, fungi of the species Aureobasidium pullulans and archaea of the species Methanosarcina mazei S-6T, deposited on cotton wool, are able to survive, and their numbers decreased equally, regardless of whether the microorganisms belong to different taxonomic groups. The main factors for the long-term survival could be the result of their dehydration and partial lyophilization in the vacuum of near-Earth space. For the first time, after being in outer space, cyst-like cells of the archaea strain M. mazei S-6T and a 14-day delay in their growth were detected when cultured on a nutrient medium compared to the ground-based control strain. In 30% of fungi species strains A. pullulans, isolated after a two-year stay in outer space, the resistance to γ-radiation increased compared to the control strain. It was found that the reaction to the action of various concentrations of hydrogen peroxide and 1% chlorine in the surviving strains of the fungus A. pullulans on the ISS is less pronounced than in the control strain.

Transverse Kerker effect in all-dielectric spheroidal particles.

Kerker effect is one of the unique phenomena in modern electrodynamics. Due to overlapping of electric and magnetic dipole moments, all-dielectric particles can be invisible in forward or backward directions. In our paper we propose new conditions between resonantly excited electric dipole and magnetic quadrupole in ceramic high index spheroidal particles for demonstrating transverse Kerker effect. Moreover, we perform proof-of-concept microwave experiment and demonstrate dumbbell radiation pattern with suppressed scattering in both forward and backward directions and enhanced scattering in lateral directions. Our concept is promising for future planar lasers, nonreflected metasurface and laterally excited waveguides and nanoantennas.

Low-Temperature Oxidation of Hydrogen Sulfide and Formaldehyde Pollutants in Humid Air by UV Radiation at 184.95 and 253.65 nm.

An experimental study of the oxidation of hydrogen sulfide and formaldehyde impurities in humid air by ultraviolet radiation at wavelengths of 184.95 and 253.65 nm has been carried out at a pressure of 1 atm, an initial temperature of 20 °C, a relative humidity of 90%, and a flow rate of the gas mixture of 4920 m3/h. The initial concentrations of hydrogen sulfide and formaldehyde in air ranged from 8 to 20 and from 2.9 to 7.2 mg/m3, respectively. The photochemical kinetic mechanism was proposed for a numerical simulation of the low-temperature photooxidation of hydrogen sulfide and formaldehyde pollutants as well as the formation of ozone in humid air. The mechanism consists of 7 and 4 photochemical reactions initiated by UV radiation at wavelengths of 184.95 and 253.65 nm, respectively, and 62 reversible individual chemical reactions involving 32 chemical species (radicals, atoms, and molecules). The obtained results of numerical simulation are in good agreement with experimental data.