Performance Modeling of an RF Coaxial Plasma Thruster

The RF plasma thruster has considerable potential to ease the impact of severe constraints on power, mass, volume and lifetime of microsatellite propulsion systems. This concept is classified as an electrothermal propulsion system and exploits RF capacitively coupled discharge (RFCCD) for heating of a propellant. The plasma is characterized as a low-power discharge possessing a low-current density with high uniformity and propagating through low-pressure gas. To assess computationally the thruster’s propulsive capabilities as a function of mass flow rate, electrode separation, RF frequency and power input, a numerical model comprises particle-in-cell/Monte Carlo (PIC/MCC) and Direct Simulation Monte Carlo (DSMC) algorithms. Thruster performance is investigated by permuting electrode geometry (0.5 - 2 cm), chamber pressure (0.05 - 50 Torr), applied voltage (100 - 500 V), and frequency (10 - 1000 MHz). For this parameter space, PIC/MCC determines overall trends in plasma characteristics. One selected case (3 Torr, 500 V, 200 MHz) and its set of conditions (plasma density, plasma heating, gas temperature, etc.) form the basis for an in-depth flow field and thrust performance analysis with DSMC. Assuming adiabatic wall conditions, the RF plasma thruster achieves a specific impulse of 104.4 s with Argon at the throat Reynolds number of 25. The RF heating increases the specific impulse by 125 %. This study shows that propulsive capability of the RF plasma thruster can be enhanced by increasing the discharge chamber length, redesigning the nozzle contour, and using propellants with lower molecular weights

Пульмональный Лангергансоклеточный гистиоцитоз легких: клиническое наблюдение в стадии раннего поражения

Histocytosis X is a rare disease of unknown etiology involving the reticuloendothelial system. We present a case of a 32 year-old man diagnosed with Pulmonary Histocytisis X. The CT image of the lungs showed disseminated disease with the formation of cyst-like cavities, which were histologically verified using lung biopsy. Лангергансоклеточный гистиоцитоз (гистиоцитоз Х) – заболевание ретикулогистиоцитарной системы неизвестной этиологии. Представлен клинический случай данной патологии у мужчины 32 лет с характерной компьютерно-томографической картиной легких в виде диссеминированного процесса с формированием кистозных полостей, который верифицирован морфологически с помощью биопсии легких.

Pulmonary histocytosis X: clinical observation of early-stage disease

Histocytosis X is a rare disease of unknown etiology involving the reticuloendothelial system. We present a case of a 32 year-old man diagnosed with Pulmonary Histocytisis X. The CT image of the lungs showed disseminated disease with the formation of cyst-like cavities, which were histologically verified using lung biopsy

Long interspersed nuclear element-1 methylation status in the circulating DNA from blood of patients with malignant and chronic inflammatory lung diseases

Along with other malignant diseases, lung cancer arises from the precancerous lung tissue state. Aberrant DNA methylation (hypermethylation of certain genes and hypomethylation of retrotransposons) is known as one of the driving forces of malignant cell transformation. Epigenetic changes were shown to be detectable in DNA, circulating in the blood (cirDNA) of cancer patients, indicating the possibility to use them as cancer markers. The current study is the first to compare the Long interspersed nuclear element-1 (LINE-1) methylation level in the blood from lung cancer patients before treatment versus different control groups as healthy subjects, patients with bronchitis and patients with chronic obstructive pulmonary disease (COPD). The concentration of LINE-1 methylated fragments, region 1 (LINE-1 methylated, LINE-1-met) was estimated by quantitative methyl-specific PCR. The total concentration of the circulating LINE-1 copies was measured by qPCR specific for LINE-1 region 2, which was selected due to its CpG methylation-independent sequence (LINE-1-Ind). Both LINE-1 methylation level and LINE-1 methylation index (LINE-1-met/LINE-1-Ind ratio) was decreased in lung cancer patients compared with the joint control group (healthy subjects + patients with bronchitis + COPD patients) (Mann-Whitney U-test, P = 0.016). We also found that the tendency of LINE-1 methylation index decreases in the cirDNA from lung cancer patients versus COPD patients (Mann-Whitney U-test, P = 0.07). Our data indicate that the quantitative analysis of the LINE-1 methylation level in the cirDNA is valuable for discrimination of lung cancer patients from patients with chronic inflammatory lung diseases. © 2021 Lippincott Williams and Wilkins. All rights reserved

Siberian larch (Larix sibirica Ledeb.) mitochondrial genome assembled using both short and long nucleotide sequence reads is currently the largest known mitogenome

Background: Plant mitochondrial genomes (mitogenomes) can be structurally complex while their size can vary from similar to 222 Kbp inBrassica napusto 11.3 Mbp inSilene conica. To date, in comparison with the number of plant species, only a few plant mitogenomes have been sequenced and released, particularly for conifers (the Pinaceae family). Conifers cover an ancient group of land plants that includes about 600 species, and which are of great ecological and economical value. Among them, Siberian larch (Larix sibiricaLedeb.) represents one of the keystone species in Siberian boreal forests. Yet, despite its importance for evolutionary and population studies, the mitogenome of Siberian larch has not yet been assembled and studied. Results: Two sources of DNA sequences were used to search for mitochondrial DNA (mtDNA) sequences: mtDNA enriched samples and nucleotide reads generated in the de novo whole genome sequencing project, respectively. The assembly of the Siberian larch mitogenome contained nine contigs, with the shortest and the largest contigs being 24,767 bp and 4,008,762 bp, respectively. The total size of the genome was estimated at 11.7 Mbp. In total, 40 protein-coding, 34 tRNA, and 3 rRNA genes and numerous repetitive elements (REs) were annotated in this mitogenome. In total, 864 C-to-U RNA editing sites were found for 38 out of 40 protein-coding genes. The immense size of this genome, currently the largest reported, can be partly explained by variable numbers of mobile genetic elements, and introns, but unlikely by plasmid-related sequences. We found few plasmid-like insertions representing only 0.11% of the entire Siberian larch mitogenome. Conclusions: Our study showed that the size of the Siberian larch mitogenome is much larger than in other so far studied Gymnosperms, and in the same range as for the annual flowering plantSilene conica(11.3 Mbp). Similar to other species, the Siberian larch mitogenome contains relatively few genes, and despite its huge size, the repeated and low complexity regions cover only 14.46% of the mitogenome sequence

Siberian larch (Larix sibirica Ledeb.) mitochondrial genome assembled using both short and long nucleotide sequence reads is currently the largest known mitogenome : научное издание

Статья из журнала. Научное издание.Background: Plant mitochondrial genomes (mitogenomes) can be structurally complex while their size can vary from similar to 222 Kbp inBrassica napusto 11.3 Mbp inSilene conica. To date, in comparison with the number of plant species, only a few plant mitogenomes have been sequenced and released, particularly for conifers (the Pinaceae family). Conifers cover an ancient group of land plants that includes about 600 species, and which are of great ecological and economical value. Among them, Siberian larch (Larix sibiricaLedeb.) represents one of the keystone species in Siberian boreal forests. Yet, despite its importance for evolutionary and population studies, the mitogenome of Siberian larch has not yet been assembled and studied. Results: Two sources of DNA sequences were used to search for mitochondrial DNA (mtDNA) sequences: mtDNA enriched samples and nucleotide reads generated in the de novo whole genome sequencing project, respectively. The assembly of the Siberian larch mitogenome contained nine contigs, with the shortest and the largest contigs being 24,767 bp and 4,008,762 bp, respectively. The total size of the genome was estimated at 11.7 Mbp. In total, 40 protein-coding, 34 tRNA, and 3 rRNA genes and numerous repetitive elements (REs) were annotated in this mitogenome. In total, 864 C-to-U RNA editing sites were found for 38 out of 40 protein-coding genes. The immense size of this genome, currently the largest reported, can be partly explained by variable numbers of mobile genetic elements, and introns, but unlikely by plasmid-related sequences. We found few plasmid-like insertions representing only 0.11% of the entire Siberian larch mitogenome. Conclusions: Our study showed that the size of the Siberian larch mitogenome is much larger than in other so far studied Gymnosperms, and in the same range as for the annual flowering plantSilene conica(11.3 Mbp). Similar to other species, the Siberian larch mitogenome contains relatively few genes, and despite its huge size, the repeated and low complexity regions cover only 14.46% of the mitogenome sequence

Diversity and Distribution of Helminths in Wild Ruminants of the Russian Arctic: Reindeer (<i>Rangifer tarandus</i>), Muskoxen (<i>Ovibos moschatus</i>), and Snow Sheep (<i>Ovis nivicola</i>)

The Russian Arctic supports wild sympatric ruminants and their data-deficient helminths. In this study, we: (1) collected fecal samples of wild and semiwild reindeer (Rangifer tarandus), muskoxen (Ovibos moschatus), and snow sheep (Ovis nivicola) across Palearctic North territories: Arkhangelsk Oblast (including Novaya Zemlya archipelago), Karelia and Sakha Republics, Kola, Yamal, Taimyr, and Chukotka Peninsulas, Bering, Svalbard, and Wrangel Islands; (2) conducted a coprological survey (noninvasive life-time method preferable for protected animals) to obtain eggs and larvae of helminths inhabiting digestive, respiratory, nervous, and muscular systems; (3) identified helminths according to their morphology and DNA sequences; (4) estimated parasite load per host; (5) analyzed our findings. Varestrongylus eleguneniensis (in reindeer) was reported for the Palearctic for the first time, while Orthostrongylus sp. was reported both for R. tarandus and for the Palearctic for the first time. Capillarid-type eggs were reported for snow sheep for the first time. The question of the role of wild Arctic ruminants as vectors for rotifers was raised