Epithelial organoids are stem cell–derived tissues that approximate aspects of real organs, and thus they have potential as powerful tools in basic and translational research. By definition, they ...self-organize, but the structures formed are often heterogeneous and irreproducible, which limits their use in the lab and clinic. We describe methodologies for spatially and temporally controlling organoid formation, thereby rendering a stochastic process more deterministic. Bioengineered stem cell microenvironments are used to specify the initial geometry of intestinal organoids, which in turn controls their patterning and crypt formation. We leveraged the reproducibility and predictability of the culture to identify the underlying mechanisms of epithelial patterning, which may contribute to reinforcing intestinal regionalization in vivo. By controlling organoid culture, we demonstrate how these structures can be used to answer questions not readily addressable with the standard, more variable, organoid models.
Phenotypic diversity in poultry has been mainly driven by artificial selection and genetic drift. These led to the adaptation to the environment and the development of specific phenotypic traits of ...chickens in response to their economic use. This study evaluated genetic diversity within and between Russian breeds and populations using Illumina Chicken 60K SNP iSelect BeadChip by analysing genetic differences between populations with Hudson's fixation index (FST statistic) and heterozygosity. We estimated the effect of rare alleles and linkage disequilibrium (LD) on these measurements. To assess the effect of LD on the genetic diversity population, we carried out the LD-based pruning (LD<0.5 and LD<0.1) for seven chicken populations combined (I) or separately (II). LD pruning was specific for different dataset groups. Because of the noticeably large sample size in the Russian White RG population, pruning was substantial for Dataset I, and FST values were only positive when LD<0.1 pruning was applied. For Dataset II, the LD pruning results were confirmed by examining heterozygosity and alleles' frequency distribution. LD between single nucleotide polymorphisms was consistent across the seven chicken populations, except the Russian White RG population with the smallest r2 values and the largest effective population size. Our findings suggest to study variability in each population LD pruning has to be carried separately not after merging to avoid bias in estimates.
The analysis of the results of experimental researches on revealing the mechanisms of vortex formation in channels of complex geometry in the neutral and conductive media is carried out. The ...directions of researches related to the study of mechanisms of vortex generation and accumulation of energy by large-scale vortex structures are considered for the possibility of predictions of the man-made accidents and catastrophic natural phenomena. The main goal of ongoing investigations is the solution of the task aimed at improving the safety of nuclear power installations and, in particular, of the fast neutron reactors with liquid-metal coolants, and the prevention of emergency modes arising from acoustic, magnetic and hydrodynamic resonance effects.
Viruses infecting main ornamental plants: an overview Mitrofanova, Irina Vjacheslavovna; Zakubanskiy, Alexsandr Vladimirovich; Mitrofanova, Olga Vladimirovna
Ornamental Horticulture,
06/2018, Volume:
24, Issue:
2
Journal Article
Peer reviewed
Open access
Ornamental plants are cultivated for decorative and utility purposes in urban landscapes throughout the world. They are much valued for their aesthetic properties and constitute an important part of ...the global horticulture industry. Plant viruses and viroids of various taxonomic groups have a significant negative impact on ornamentals provoking a wide range of symptoms, reducing both decorative value and quality of propagated material and causing large economic damage. A significant growth of the ornamental plants market in recent years promotes the spread of viral diseases. Therefore, systematization of data on virus and viroid phytopathogens diversity in these cultures is an urgent research task. Among the most popular ornamentals are chrysanthemum, rose, clematis, canna, and lavender. More than fifty viruses and viroids from 17 different families (including two viroid families) have been identified in these crops to date. In the presented review, we described the variety of these pathogens and their effect on the above-mentioned ornamentals
Abstract
The theoretical and computational analysis proposed in this work is aimed at identifying the features of thermal and hydrodynamic processes carried out in the steam-generating channels of ...the ship type water-moderated nuclear power installations. It is shown that the complex geometry of the thermohydraulic tract curvilinear channels of the steam generating system has a significant effect on the efficiency of the transport nuclear power installation. In addition to the formation of large-scale vortex structures and swirling flow in the pipeline, the phenomenon of the swirling flow crisis is revealed, under which the low-frequency component of the acoustic spectrum is enhanced. The scientific and applied significance of the proposed research is associated with the need to ensure a wide range of operational changes in efficient and safe operation power modes of icebreaker nuclear power installations. The research, aimed at developing the principles of physical and mathematical modeling of complex vortex flows, is necessary to optimize the design parameters of the thermal power equipment elements of new generation ship nuclear power installations in order to ensure increased safety and reliability of their operation.
Abstract
In Russia, the volume of restoration and maintenance work of drainage reclamation systems has significantly decreased, the number of trained reclamation specialists has decreased, most of ...the objects need reconstruction, and the documentation and schemes of pipes and channels of drainage systems have been lost. Accordingly, the development of agricultural drainage reclamation will require large amounts of financial and labor costs. The aim of the work is to present an alternative approach to assessing the status of these systems for making management decisions using an unmanned aerial system (UAS), which allows you to quickly obtain high quality aerial photographs (2-7 cm/pixel) of an agricultural area up to 50 hectares in one flight. In addition to the unmanned aerial vehicle, the UAS also includes an onboard complex, a payload and a ground control station. The flight group carries out all stages of data acquisition and preprocessing in an automated mode using specialized software. In the course of the experimental studies, the main elements of the considered approach to monitoring drainage systems are highlighted: the period of aerial photography, determination of the pipes and canals schemes, determination of waterlogging zones on agricultural areas and breakdowns of a reclamation system, monitoring in dynamics. As a result, when solving the problem of monitoring drainage reclamation systems, the use of UAS seems to be a relevant and promising approach, which makes it possible to assess the object status promptly.
Conducted analytical studies have shown that in complex geometry channels with three-dimensional curvature, and a variable cross-section area, the conditions leading to large-scale vortex formation ...and swirl flow. In this case, not only the mode of swirl flow can be implemented, but also the effect of locking the flow due to the crisis of the swirl flow. It is shown that the crisis of swirl flow can take place in various power, motor, chemical-technological devices and other technical devices associated with the use of high-speed swirl flows of liquids or gases. A characteristic feature of such devices is the presence of large pressure losses required for the organization of flow swirling in channels of complex geometry. In the present paper, the manifestation of the swirl flow crisis is considered on the example of modeling the processes of hydrodynamics and heat exchange in the channels of an icebreaker steam generating installation.
Hexaploid bread wheat evolved from a rare hybridisation, which resulted in a loss of genetic diversity in the wheat D-genome with respect to the ancestral donor, Aegilops tauschii. Novel genetic ...variation can be introduced into modern wheat by recreating the above hybridisation; however, the information associated with the Ae. tauschii accessions in germplasm collections is limited, making rational selection of accessions into a re-synthesis programme difficult. We describe methodologies to identify novel diversity from Ae. tauschii accessions that combines Bayesian analysis of genotypic data, sub-species diversity and geographic information that summarises variation in climate and habitat at the collection point for each accession. Comparisons were made between diversity discovered amongst a panel of Ae. tauschii accessions, bread wheat varieties and lines from the CIMMYT synthetic hexaploid wheat programme. The selection of Ae. tauschii accessions based on differing approaches had significant effect on diversity within each set. Our results suggest that a strategy that combines several criteria will be most effective in maximising the sampled variation across multiple parameters. The analysis of multiple layers of variation in ex situ Ae. tauschii collections allows for an informed and rational approach to the inclusion of wild relatives into crop breeding programmes.
Throughout history, humans have been attempting to develop the ornamental features of domestic animals in addition to their productive qualities. Many chicken breeds have developed tufts of elongated ...feathers that jut out from the sides and bottom of the beak, leading to the phenotype known as muffs and beard. It is an incomplete autosomal dominant phenotype determined by the Mb locus localised on chromosome GGA27. This project aimed to analyse the genetic diversity of chicken breeds using full genomic genotyping with the Chicken 60K BeadChip. A total of 53,313 Single Nucleotide Polymorphisms were analysed. DNA was obtained from breeds with the muffs and beard as a marker phenotype: Faverolles (n = 20), Ukrainian Muffed (n = 18), Orloff (n = 20), Novopavlov White (n = 20), and Novopavlov Coloured (n = 15). The Russian White (n = 20) was selected as an alternative breed without the muffs and beard phenotype. The chickens are owned by the Centre of Collective Use "Genetic Collection of Rare and Endangered Breeds of Chickens" (St. Petersburg region, Pushkin), and are also included in the Core Shared Research Facility (CSRF) and/or Large-Scale Research Facility (LSRF). Multidimensional scaling revealed that the Novopavlov White and the Novopavlov Coloured populations formed a separate group. The Ukrainian Muffed and the Orloff have also been combined into a separate group. Based on cluster analysis, with the cross-validation error and the most probable number of clusters K = 4 taken into account, the Orloff was singled out as a separate group. The Ukrainian Muffed exhibited a notable similarity with the Orloff under the same conditions. At K = 5, the populations of the Novopavlov White and the Novopavlov Coloured diverged. Only at K = 6, a distinct and separate cluster was formed by the Ukrainian Muffed. The Russian White had the greatest number of short (1-2 Mb) homozygous regions. If the HOXB8 gene is located between 3.402 and 3.404 Mb on chromosome GGA27, homozygous regions are rarely found in the chickens with the muffs and beard phenotype. Scanning the chicken genome with the Chicken 60K BeadChip provided enough information about the genetic diversity of the chicken breeds for the peculiarities of the development of the ornamental muffs and beard phenotypes in them to be understood. For example, Phoenix bantams, whose tail feathers grow throughout their lives, require greater consideration of husbandry conditions.
The mechanism of generation of acoustic oscillations associated with the formation of stable vortex structures in the moving fluid was considered for the impact swirl flow. Experimental studies were ...carried out to determine the relationship between large-scale vortex motion and acoustic effects in hydro-mechanical systems. It was shown that a sharp change of the amplitude-frequency characteristic of the acoustic oscillations of hydro-mechanical system corresponds to the maximal flow rate of the swirl flow. The established connection between the generation of sound waves and geometrical and regime parameters of the hydro-mechanical system formed the basis for the developed method of diagnostics of the processes of vortex formation.
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