Гляциогеофизические инженерные изыскания для подготовки лётного поля в районе российской станции Мирный (Восточная Антарктида)

Main results of glaciological and geophysical engineering surveys, conducted during three summer field seasons of 2013– 2016 (59–61st Russian Antarctic Expeditions  – RAE) near the Russian Station Mirny (East Antarctica), are discussed in the paper. Objective of these works was to site and then to organize a new airfield for landing of medium-range aircrafts with ski landing gears. Investigations included aerial photography, GPR surveys (georadar profiling), ice core drilling, and installation of landmarks to measure velocity of the glacier motion. The GSSI ground-penetrating radars with the main frequencies of 270 MHz and 900 MHz were used. In addition, special explorations were conducted for detecting the englacial crevasses by means of remote-sensing methods. The GPR data allowed a revealing the boundary between snow-andfirn thickness and atmospheric ice. In the course of processing of 252 travel-time curves of the diffracted waves a kinematic model of the sub-surface part of the glacier has been constructed. It was found that the dielectric permittivity of the snowfirn thickness averages 2.43; similar value for the atmospheric ice amounts to 3.0. The GPR data made it possible to determine intraglacial (englacial) crevasses and to choose the most favorable field for the landing. On February 10, 2016, the first middle-range aircraft DC-3T (BT-67) had landed onto the new run-way near the station Mirny.Рассматриваются результаты гляциогеофизических инженерных изысканий в трёх летних полевых сезонах 2013–2016  гг. (59–61-я Российские антарктические экспедиции) в районе станции Мирный (Восточ- ная Антарктида). Цель работы  – выбор места посадочной площадки для приёма среднемагистральных самолётов на лыжном шасси и последующая её организация. Работы предусматривали проведение аэрофотосъёмки, георадарного профилирования, кернового бурения, а также установку вех для изме- рения скорости течения ледника. Георадарные данные позволили выявить внутриледниковые трещины и выбрать наиболее удачное место для посадочной площадки, на которую 10 февраля 2016 г. был принят самолёт DC-3Т (BT-67)

Аэрофотосъёмка районов российских антарктических станций Мирный и Прогресс в сезон 2014/15 г.

Aerial photographing performed during the field season of 60th Russian Antarctic Expedition (2014/2015) made possible to construct a photoplan of the Mirny station. Its size is 3,5×3,5 km with resolution of 16 pixels/cm, and it will be used as a basis for designing of new airport. Similar work had been done over the Progress station along the route “Progress – Vostok”, about 35 km long. It was found that any crevasses dangerous for people and transport were absent on this area.В результате работ летом 2014/15 г. составлен фотоплан района станции Мирный размером 3,5 × 3,5 км с детальностью 16 пиксель/см; он станет основой при планировании здесь нового аэродрома. Аналогичная работа выполнена в районе станции Прогресс на участке протяжённостью около 35 км вдоль трассы «Прогресс – Восток». Установлено, что трещины, опасные для людей и транспортной техники, на этой территории отсутствуют

Glaciological and geophysical investigations aimed at organization of a new airfield at the Station Mirny (East Antarctica)

Main results of glaciological and geophysical engineering surveys, conducted during three summer field seasons of 2013– 2016 (59–61st Russian Antarctic Expeditions  – RAE) near the Russian Station Mirny (East Antarctica), are discussed in the paper. Objective of these works was to site and then to organize a new airfield for landing of medium-range aircrafts with ski landing gears. Investigations included aerial photography, GPR surveys (georadar profiling), ice core drilling, and installation of landmarks to measure velocity of the glacier motion. The GSSI ground-penetrating radars with the main frequencies of 270 MHz and 900 MHz were used. In addition, special explorations were conducted for detecting the englacial crevasses by means of remote-sensing methods. The GPR data allowed a revealing the boundary between snow-andfirn thickness and atmospheric ice. In the course of processing of 252 travel-time curves of the diffracted waves a kinematic model of the sub-surface part of the glacier has been constructed. It was found that the dielectric permittivity of the snowfirn thickness averages 2.43; similar value for the atmospheric ice amounts to 3.0. The GPR data made it possible to determine intraglacial (englacial) crevasses and to choose the most favorable field for the landing. On February 10, 2016, the first middle-range aircraft DC-3T (BT-67) had landed onto the new run-way near the station Mirny

Aerial photography of Russian Antarctic stations Mirny and Progress in summer of 2014/15

Aerial photographing performed during the field season of 60th Russian Antarctic Expedition (2014/2015) made possible to construct a photoplan of the Mirny station. Its size is 3,5×3,5 km with resolution of 16 pixels/cm, and it will be used as a basis for designing of new airport. Similar work had been done over the Progress station along the route “Progress – Vostok”, about 35 km long. It was found that any crevasses dangerous for people and transport were absent on this area

Multiple Drug-Induced Stress Responses Inhibit Formation of Escherichia coli Biofilms

In most ecosystems, bacteria exist primarily as structured surface-associated biofilms that can be highly tolerant to antibiotics and thus represent an important health issue. Here, we explored drug repurposing as a strategy to identify new antibiofilm compounds, screening over 1,000 compounds from the Prestwick Chemical Library of approved drugs for specific activities that prevent biofilm formation by Escherichia coli. Most growth-inhibiting compounds, which include known antibacterial but also antiviral and other drugs, also reduced biofilm formation. However, we also identified several drugs that were biofilm inhibitory at doses where only a weak effect or no effect on planktonic growth could be observed. The activities of the most specific antibiofilm compounds were further characterized using gene expression analysis, proteomics, and microscopy. We observed that most of these drugs acted by repressing genes responsible for the production of curli, a major component of the E. coli biofilm matrix. This repression apparently occurred through the induction of several different stress responses, including DNA and cell wall damage, and homeostasis of divalent cations, demonstrating that biofilm formation can be inhibited through a variety of molecular mechanisms. One tested drug, tyloxapol, did not affect curli expression or cell growth but instead inhibited biofilm formation by suppressing bacterial attachment to the surface. IMPORTANCE The prevention of bacterial biofilm formation is one of the major current challenges in microbiology. Here, by systematically screening a large number of approved drugs for their ability to suppress biofilm formation by Escherichia coli, we identified a number of prospective antibiofilm compounds. We further demonstrated different mechanisms of action for individual compounds, from induction of replicative stress to disbalance of cation homeostasis to inhibition of bacterial attachment to the surface. Our work demonstrates the potential of drug repurposing for the prevention of bacterial biofilm formation and suggests that also for other bacteria, the activity spectrum of antibiofilm compounds is likely to be broad