Dessins, their delta-matroids and partial duals

Given a map $\mathcal M$ on a connected and closed orientable surface, the delta-matroid of $\mathcal M$ is a combinatorial object associated to $\mathcal M$ which captures some topological information of the embedding. We explore how delta-matroids associated to dessins d'enfants behave under the action of the absolute Galois group. Twists of delta-matroids are considered as well; they correspond to the recently introduced operation of partial duality of maps. Furthermore, we prove that every map has a partial dual defined over its field of moduli. A relationship between dessins, partial duals and tropical curves arising from the cartography groups of dessins is observed as well.Comment: 34 pages, 20 figures. Accepted for publication in the SIGMAP14 Conference Proceeding

ОСНОВНІ ДИНАМІЧНІ ПОКАЗНИКИ МАЛОПОТУЖНИХ МАГНІТОЕЛЕКТРИЧНИХ ДВИГУНІВ

In clause the basic dynamic parameters low-power magnetoelectric of engines of a disk type are considered.The settlement formulas for an estimation of good quality, electromechanical and electromagnetic constanttime at an initial stage of designing of engines are received.В статье рассмотрены основные динамические показатели маломощных магнитоэлектрических двигателей дискового типа. Получены расчётные формулы для оценки добротности, электромеханической и электромагнитной постоянных времени на начальной стадии проектирования двигателей.В статті розглянуто основні динамічні показники малопотужних магнітоелектричних двигунів дискового типу. Отримано розрахункові формули для оцінки добротності, електромеханічної та електромагнітної сталих часу на початковій стадії проектування двигунів

ФУНКЦИИ И ОСОБЕННОСТИ УПРАВЛЕНИЯ ЭЛЕКТРОЭНЕРГЕТИЧЕСКИМ КОМПЛЕКСОМ В ПЕРИОД ЕГО РЕФОРМИРОВАНИЯ

The principles and peculiarities of the corporate changes in power industry on the basis of «organizational development» theory have been considered in the paper. Special attention has been given to the functions of top-management in the transition period.Рассмотрены принципы и особенности корпоративных изменений в электроэнергетической отрасли с позиций теории «организационного развития». Особое внимание уделено функциям топ-менеджмента в период реформирования

The Beta Ansatz: A Tale of Two Complex Structures

Brane tilings, sometimes called dimer models, are a class of bipartite graphs on a torus which encode the gauge theory data of four-dimensional SCFTs dual to D3-branes probing toric Calabi-Yau threefolds. An efficient way of encoding this information exploits the theory of dessin d’enfants, expressing the structure in terms of a permutation triple, which is in turn related to a Belyi pair, namely a holomorphic map from a torus to a P1 with three marked points. The procedure of a-maximization, in the context of isoradial embeddings of the dimer, also associates a complex structure to the torus, determined by the R-charges in the SCFT, which can be compared with the Belyi complex structure. Algorithms for the explicit construction of the Belyi pairs are described in detail. In the case of orbifolds, these algorithms are related to the construction of covers of elliptic curves, which exploits the properties of Weierstraß elliptic functions. We present a counter example to a previous conjecture identifying the complex structure of the Belyi curve to the complex structure associated with R-charges

Противовирусная активность лекарственного препарата на основе РНК двуспиральной натриевой соли в отношении SARS-CoV-2 in vitro

Scientific relevance. Innate immune activation in the early phases of COVID-19 infection and subsequent interferon induction may help control viral replication and protect cells not yet infected with SARS-CoV-2. Thus, immunostimulants that induce interferon (IFN), including double-stranded RNA-based agents, are a promising means of post-exposure prophylaxis and treatment of COVID-19 at early stages.Aim. The study evaluated the in vitro antiviral activity of a double-stranded RNA sodium salt-based medicinal product against SARS-CoV-2.Materials and methods. The authors analysed the double-stranded RNA sodium salt-based medicinal product RADAMIN®VIRO using Vero cells and the Delta variant of SARS-CoV-2 (B.1.617). The virus titre was calculated as the tissue cytopathic dose that caused 50% cell death. The authors measured the content of IFN-α and IFN-γ in the culture fluid by enzyme immunoassay and assessed the viral load by real-time polymerase chain reaction (using the cycle threshold value) and by titration (using Vero cells).Results. The studied double-stranded RNA sodium salt-based medicinal product at a concentration of 250 or 500 μg/mL induced IFN-α and IFN-γ expression by Vero cells, thus increasing their resistance to SARS-CoV-2. The authors evaluated the antiviral activity of the medicinal product based on the virus titre, viral load, and cell monolayer damage. The antiviral activity became clear 24 h after treatment, which confirmed the ability of the medicinal product to inhibit the replication of the SARS-CoV-2 virus in vitro as early as the first day after infection.Conclusions. The double-stranded RNA sodium salt-based medicinal product induced IFN-α and IFN-γ synthesis in Vero cells, increasing their resistance to SARS-CoV-2 infection in vitro. These results demonstrate the immunomodulatory and antiviral potential of the medicinal product.Актуальность. Активация механизмов врожденного иммунитета на ранних фазах развития инфекции COVID-19 и, как следствие, последующая индукция продукции интерферонов может способствовать контролю репликации вируса и защите еще неинфицированных SARS-CoV-2 клеток. В связи с этим в качестве средств постконтактной профилактики и лечения COVID-19 на ранних этапах представляется перспективным применение иммуностимулирующих препаратов, вызывающих индукцию интерферонов, в том числе препаратов на основе двуспиральной РНК.Цель. Оценка противовирусной активности лекарственного препарата на основе РНК двуспиральной натриевой соли в отношении вируса SARS-CoV-2 in vitro.Материалы и методы. Препарат на основе РНК двуспиральной натриевой соли (РАДАМИН®ВИРО). Эксперименты выполняли на культуре клеток Vero. В исследовании использовали вариант дельта вируса SARS-CoV-2 (B.1.617). Проводили оценку цитопатического действия вируса. Титр вируса рассчитывали как показатель тканевой цитопатической дозы, вызывающей гибель 50% клеток. Содержание интерферонов α и γ в культуральной жидкости определяли с помощью метода иммуноферментного анализа, вирусную нагрузку – методом полимеразной цепной реакции в реальном времени (по показателю Ct) и титр вируса – титрованием на культуре клеток Vero.Результаты. Внесение препарата на основе РНК двуспиральной натриевой соли в концентрациях 250 мкг/мл и 500 мкг/мл к клеткам линии Vero приводит к индукции секреции интерферонов α и γ, что повышает резистентность клеток к заражению вирусом SARS-CoV-2. Противовирусная активность исследуемого препарата, оцениваемая по значениям показателей титра вируса, вирусной нагрузки и уровня поражения клеточного монослоя, отмечается через 24 ч после его воздействия, что показывает способность препарата задерживать размножение вируса SARS-CoV-2 in vitro уже в течение первых суток после заражения.Выводы. Препарат на основе РНК двуспиральной натриевой соли индуцирует синтез интерферонов α и γ клетками линии Vero, повышая устойчивость клеток к заражению SARS-CoV-2 in vitro, что свидетельствует о иммуномодулирующем и противовирусном потенциале исследованного препарата

Inhibition of Host Vacuolar H+-ATPase Activity by a Legionella pneumophila Effector

Legionella pneumophila is an intracellular pathogen responsible for Legionnaires' disease. This bacterium uses the Dot/Icm type IV secretion system to inject a large number of bacterial proteins into host cells to facilitate the biogenesis of a phagosome permissive for its intracellular growth. Like many highly adapted intravacuolar pathogens, L. pneumophila is able to maintain a neutral pH in the lumen of its phagosome, particularly in the early phase of infection. However, in all cases, the molecular mechanisms underlying this observation remain unknown. In this report, we describe the identification and characterization of a Legionella protein termed SidK that specifically targets host v-ATPase, the multi-subunit machinery primarily responsible for organelle acidification in eukaryotic cells. Our results indicate that after being injected into infected cells by the Dot/Icm secretion system, SidK interacts with VatA, a key component of the proton pump. Such binding leads to the inhibition of ATP hydrolysis and proton translocation. When delivered into macrophages, SidK inhibits vacuole acidification and impairs the ability of the cells to digest non-pathogenic E. coli. We also show that a domain located in the N-terminal portion of SidK is responsible for its interactions with VatA. Furthermore, expression of sidK is highly induced when bacteria begin to enter new growth cycle, correlating well with the potential temporal requirement of its activity during infection. Our results indicate that direct targeting of v-ATPase by secreted proteins constitutes a virulence strategy for L. pneumophila, a vacuolar pathogen of macrophages and amoebae

Inositol Hexakisphosphate-Induced Autoprocessing of Large Bacterial Protein Toxins

Large bacterial protein toxins autotranslocate functional effector domains to the eukaryotic cell cytosol, resulting in alterations to cellular functions that ultimately benefit the infecting pathogen. Among these toxins, the clostridial glucosylating toxins (CGTs) produced by Gram-positive bacteria and the multifunctional-autoprocessing RTX (MARTX) toxins of Gram-negative bacteria have distinct mechanisms for effector translocation, but a shared mechanism of post-translocation autoprocessing that releases these functional domains from the large holotoxins. These toxins carry an embedded cysteine protease domain (CPD) that is activated for autoprocessing by binding inositol hexakisphosphate (InsP6), a molecule found exclusively in eukaryotic cells. Thus, InsP6-induced autoprocessing represents a unique mechanism for toxin effector delivery specifically within the target cell. This review summarizes recent studies of the structural and molecular events for activation of autoprocessing for both CGT and MARTX toxins, demonstrating both similar and potentially distinct aspects of autoprocessing among the toxins that utilize this method of activation and effector delivery

Reaction Chemistry and Kinetics of Corn Stalk Pyrolysis without and with Ga/HZSM-5

The bifunctional Ga/HZSM-5 catalyst has been proven having the capability to increase the selectivity of aromatics production during catalytic pyrolysis of furan and woody biomass. However, the reaction chemistry and kinetics of pyrolysis of herbaceous biomass promoted by Ga/HZSM-5 is rarely reported. Pyrolysis–gas chromatography/mass spectrometry (Py–GC/MS) analysis and non-isothermal thermogravimetric analysis at four heating rates were carried out to investigate the decomposition behavior and pyrolysis kinetics of corn stalk without and with Ga/HZSM-5. The effective activation energies for corn stalk pyrolysis were calculated by using the Friedman isoconversional method. The Py–GC/MS analysis results indicated that the Ga/HZSM-5 catalyst had a high selectivity toward producing the aromatic chemicals of xylene, toluene and benzene, whereas the major products from non-catalytic pyrolysis of corn stalk were oxygenated compounds. The presence of Ga/HZSM-5 could significantly reduce the effective activation energies of corn stalk pyrolysis from 159.9–352.4 kJ mol−1 to 41.6–99.8 kJ mol−1 in the conversion range of 0.10–0.85

Novel Arenavirus Sequences in Hylomyscus sp. and Mus (Nannomys) setulosus from Côte d'Ivoire: Implications for Evolution of Arenaviruses in Africa

This study aimed to identify new arenaviruses and gather insights in the evolution of arenaviruses in Africa. During 2003 through 2005, 1,228 small mammals representing 14 different genera were trapped in 9 villages in south, east, and middle west of Côte d'Ivoire. Specimens were screened by pan-Old World arenavirus RT-PCRs targeting S and L RNA segments as well as immunofluorescence assay. Sequences of two novel tentative species of the family Arenaviridae, Menekre and Gbagroube virus, were detected in Hylomyscus sp. and Mus (Nannomys) setulosus, respectively. Arenavirus infection of Mus (Nannomys) setulosus was also demonstrated by serological testing. Lassa virus was not found, although 60% of the captured animals were Mastomys natalensis. Complete S RNA and partial L RNA sequences of the novel viruses were recovered from the rodent specimens and subjected to phylogenetic analysis. Gbagroube virus is a closely related sister taxon of Lassa virus, while Menekre virus clusters with the Ippy/Mobala/Mopeia virus complex. Reconstruction of possible virus–host co-phylogeny scenarios suggests that, within the African continent, signatures of co-evolution might have been obliterated by multiple host-switching events