Разработка численной модели аэродинамического взаимодействия высокоскоростного поезда, воздушной среды и объектов инфраструктуры

The design of high-speed railway lines (HSR) requires mandatory consideration of loads from the aerodynamic interaction of a moving train, the air environment and infrastructure facilities, acting both on structures and facilities, and on the train itself. Software systems of computational fluid dynamics are most expedient to determine the nature and intensity of the load.To find the optimal approach to modelling the processes of aerodynamic interaction between a moving high-speed train and the air environment, as well as to assess the degree of validity of the simulation, a series of calculations were performed in the ANSYS CFX software environment using various approaches to the construction of calculation models (the sliding grid method and the immersed solid method). An analysis of the results of the performed calculations makes it possible to determine the area of rational application of the considered approaches in the development of computational models of aerodynamic interaction.To verify the developed calculation models, experimental measurements of the aerodynamic impact of Sapsan high-speed electric train on the air environment were performed. Also, the developed models were verified based on the results of similar international experimental studies. Comparison of the results of numerical simulation and experimental measurements allows us to conclude that the developed computational models are sufficiently valid and can be further applied.Проектирование высокоскоростных железнодорожных магистралей (ВСМ) требует обязательного учёта нагрузок от аэродинамического взаимодействия движущегося поезда, воздушной среды и объектов инфраструктуры, действующих как на конструкции и сооружения, так и на сам поезд.Определение характера и интенсивности нагрузки наиболее целесообразно осуществлять в программных комплексах вычислительной гидрогазодинамики.В целях определения оптимального подхода кмоделированию процессов аэродинамического взаимодействия движущегося высокоскоростного поезда и воздушной среды, а также оценки степени его достоверности, в программном комплексе ANSYS CFX была выполнена серия расчётов с применением различных подходов к построению расчётных моделей (метод скользящих сеток и метод погруженного тела). Анализ их результатов позволяет определить область рационального применения рассмотренных подходов при разработке расчётных моделей аэродинамического взаимодействия.Для верификации разработанных расчётных моделей были выполнены экспериментальные измерения аэродинамического воздействия высокоскоростного электропоезда «Сапсан» на воздушную среду. Также разработанные модели были верифицированы по результатам аналогичных зарубежных экспериментальных исследований. Сопоставление результатов численного моделирования и экспериментальных измерений позволяет сделать вывод о достаточной степени достоверности разработанных расчётных моделей и возможности их дальнейшего использования

Host genetic factors associated with the range limit of a European hantavirus

The natural host ranges of many viruses are restricted to very specific taxa. Little is known about the molecular barriers between species that lead to the establishment of this restriction or generally prevent virus emergence in new hosts. Here, we identify genomic polymorphisms in a natural rodent host associated with a strong genetic barrier to the transmission of European Tula orthohantavirus (TULV). We analysed the very abrupt spatial transition between two major phylogenetic clades in TULV across the comparatively much wider natural hybrid zone between evolutionary lineages of their reservoir host, the common vole (Microtus arvalis). Genomic scans of 79,225 single nucleotide polymorphisms (SNPs) in 323 TULV-infected host individuals detected 30 SNPs that were consistently associated with the TULV clades CEN.S or EST.S in two replicate sampling transects. Focusing the analysis on 199 voles with evidence of genomic admixture at the individual level (0.1–0.9) supported statistical significance for all 30 loci. Host genomic variation at these SNPs explained up to 37.6% of clade-specific TULV infections. Genes in the vicinity of associated SNPs include SAHH, ITCH and two members of the Syngr gene family, which are involved in functions related to immune response or membrane transport. This study demonstrates the relevance of natural hybrid zones as systems not only for studying processes of evolutionary divergence and speciation, but also for the detection of evolving genetic barriers for specialized parasites

Towards Automated Classification of Zooplankton Using Combination of Laser Spectral Techniques and Advanced Chemometrics

Zooplankton identification has been the subject of many studies. They are mainly based on the analysis of photographs (computer vision). However, spectroscopic techniques can be a good alternative due to the valuable additional information that they provide. We tested the performance of several chemometric techniques (principal component analysis (PCA), non-negative matrix factorisation (NMF), and common dimensions and specific weights analysis (CCSWA of ComDim)) for the unsupervised classification of zooplankton species based on their spectra. The spectra were obtained using laser-induced breakdown spectroscopy (LIBS) and Raman spectroscopy. It was convenient to assess the discriminative power in terms of silhouette metrics (Sil). The LIBS data were substantially more useful for the task than the Raman spectra, although the best results were achieved for the combined LIBS + Raman dataset (best Sil = 0.67). Although NMF (Sil = 0.63) and ComDim (Sil = 0.39) gave interesting information in the loadings, PCA was generally enough for the discrimination based on the score graphs. The distinguishing between Calanoida and Euphausiacea crustaceans and Limacina helicina sea snails has proved possible, probably because of their different mineral compositions. Conversely, arrow worms (Parasagitta elegans) usually fell into the same class with Calanoida despite the differences in their Raman spectra

Convergent loss of chemoreceptors across independent origins of slave-making in ants

The evolution of an obligate parasitic lifestyle often leads to the reduction of morphological and physiological traits, which may be accompanied by loss of genes and functions. Slave-making ants are social parasites that exploit the work force of closely related ant species for social behaviors such as brood care and foraging. Recent divergence between these social parasites and their hosts enables comparative studies of gene family evolution. We sequenced the genomes of eight ant species, representing three independent origins of ant slavery. During the evolution of eusociality, chemoreceptor genes multiplied due to the importance of chemical communication in insect societies. We investigated the evolutionary fate of these chemoreceptors and found that slave-making ant genomes harbored only half as many gustatory receptors as their hosts’, potentially mirroring the outsourcing of foraging tasks to host workers. In addition, parasites had fewer odorant receptors and their loss shows striking patterns of convergence across independent origins of parasitism, in particular in orthologs often implicated in sociality like the 9-exon odorant receptors. These convergent losses represent a rare case of convergent molecular evolution at the level of individual genes. Thus, evolution can operate in a way that is both repeatable and reversible when independent ant lineages lose important social traits during the transition to a parasitic lifestyle

Wrong-way-round ionization and hydrophilic liquid chromatography in the analysis of insulin-like growth factors

Активное развитие протеомики и геномики приводит к все большему пониманию проблемы изучения и разработки терапевтических средств на основе пептидов. В последние годы получил широкое распространение ряд низкомолекулярных пептидов, используемых в качестве факторов мышечного роста и официально включенных в список запрещенных ВАДА препаратов. Отдельно стоит отметить, что большинство из них не проходили клинических испытаний и могут быть потенциально опасными для здоровья употребляющих их людей. Рассмотрены наиболее распространенные способы определения некоторых низкомолекулярных инсулиноподобных факторов мышечного роста с использованием метода ВЭЖХ с масс-спектрометрическим детектированием. Показано, что наибольшая эффективность разделения достигается с использованием метода обращенно-фазовой жидкостной хроматографии, при этом предел обнаружения составляет 5 нг/мл. Предложен способ определения некоторых инсулиноподобных факторов мышечного роста с использованием ВЭЖХ-ЭРИ-МС/МС в режиме “Wrong-way round ionization”, обеспечивающим аналогичную чувствительность. В данном режиме ионизация осуществляется в щелочной среде с регистрацией положительных ионов, несмотря на отсутствие явного источника протонов, путем переноса протона из иона аммония в газовой фазе. Показано существенное изменение параметров удерживания определяемых веществ за счет изменения их формы нахождения в анализируемой пробе. Рассмотрена возможность применения гидрофильной хроматографии для разделения изучаемых низкомолекулярных пептидов. Установлено, что в случае применения HILIC возможно определение количества пептидов.The recent advances in genomics and proteomics have led to an increased focus on the development of peptide therapeutics. For the last few years the usage of several low molecular weight peptides, included in WADA prohibited list, has increased dramatically. Most of them had never passed a clinical trial, and potentially can be dangerous for people. In this article, we developed a few methods of determination of several low molecular weight insulin-like growth hormones using UPLC-MS/MS. It was shown that reversed-phase liquid chromatography is the most preferred method for their separation, which can be used to achieve a 5 ng/ml limit of detection using the outlined separation and detection conditions. Wrong-way-round ionization UPLC-ESI-MS/MS method for the determination of some insulin-like human growth hormones was developed with the same sensitivity. This method can be realized in alkaline conditions with the detection of positive ions and despite the apparent lack of protons’ source, which can be taken from the ammonia ion in the gas phase. A significant change in the retention parameters was shown because of their forms of occurrence changing in the analyzed sample. The possibility of using hydrophobic interaction chromatography to separate low molecular weight peptides was studied. It was found that in the case of using HILIC it may define a limited number of peptides.The Ministry of Education of the Russian Federation (Project No 4.873.2014 / K) and RFBR (projects No 16-43-230404 r-a and No 15-03-02453 A) supported this work, which was completed using the scientific CCU KubSU equipment