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SPD (several plastic deformations) methods make it possible to obtain an ultrafine-grained structure (UFG) in larger volumes of material and thus improve its mechanical properties. The presented work focuses on the structural and mechanical changes of aluminium alloy AlMgSi0.5 (EN AW 6060) during processing by repeated extrusion through the ECAP rectangular channel. After a four-pass extrusion, the samples' microstructures were observed using an optical microscope, where refinement of the material grains was confirmed. Tensile tests determined the extrusion forces and allowed interpretation of the changes in the mechanical properties of the stressed alloy. The grain size was refined from 28.90 μm to 4.63 μm. A significant improvement in the strength of the material (by 45%) and a significant deterioration in ductility (to 60%) immediately after the first extrusion was confirmed. The third pass through the die appeared to be optimal for the chosen deformation path, while after the fourth pass, micro-cracks appeared, significantly reducing the strength of the material. Based on the measurement results, new analytical equations were formulated to predict the magnitude or intensity of the volumetric and shape deformations of the structural grain size and, in particular, the adequate increase in the strength and yield point of the material.

Chapters one to five is dedicated to the Czech organization of justice. In the introductory chapter, I have defined the key concepts and legal principles governing justice. In the second chapter, I dealt with the general division of the judicial system. The third and fourth chapters are devoted to the administrative judiciary headed by the NSS CR and the fourth chapter, subsequently to constitutional justice. The guarantor of constitutionality in the Czech Republic is the Constitutional Court, so the fourth chapter was devoted mainly to it. I discuss arbitration courts in the fifth and last chapter dedicated to the Czech judicial system. Unless they are part of the system of ordinary courts, they, like private bodies, have an irreplaceable role to play in resolving disputes. In the sixth chapter, I deal with the case- law of the European Court of Human Rights and the Constitutional Court of the Czech Republic in matters of respect for human rights in the Russian Federation, including the views of international organizations on their situation in the Russian Federation.. In the following five chapters, seventh to eleven, I described the Russian judicial system. In the beginning, I tell the reader about the structure of the Russian Federation and the specifics of separation of powers. Chapter eight was...

The aim of the article is to examine the workability of sintered powder material of aluminum alloy (Alumix 321) through severe plastic deformations under the conditions of the equal channel angular rolling (ECAR) process. Accordingly, the stress–strain analysis of the ECAR was carried out through a computer simulation using the finite element method (FEM) by Deform 3D software. Additionally, the formability of the ALUMIX 321 was investigated using the diametrical compression (DC) test, which was measured and analyzed by digital image correlation and finite element simulation. The relationship between failure mode and stress state in the ECAR process and the DC test was quantified using stress triaxiality and Lode angle parameter. It is concluded that the sintered powder material during the ECAR processing failure by a shearing fracture because in the fracture location the stress conditions were close to the pure shear (η and θ¯ ≈ 0). Moreover, the DC test revealed the potential role as the method of calibration of the fracture locus for stress conditions between the pure shear and the axial symmetry compression.

This article deals with the use of photovoltaic panels at the end of their life cycle in cement composites. Attention is focused on the properties of cement composite after 100% replacement of natural aggregate with recycled glass from photovoltaic panels. This goal of replacing natural filler sources with recycled glass is based on the updated policy of the Czech Republic concerning secondary raw materials for the period of 2019-2022, which aims to increase the self-sufficiency of the Czech Republic in raw materials by replacing primary sources with secondary raw materials. The policy also promotes the use of secondary raw materials as a tool to reduce the material and energy demands of industrial production and supports the innovations and development of a circular economy within business. The research has shown that it is possible to prepare cement composite based on recycled glass from solar panels, with compressive and flexural strength after 28 days exceeding 40 MPa and 4 MPa. Furthermore, a possible modification of the cement composite with different pigments has been confirmed, without disrupting the contact zone. Web of Science 14 21 art. no. 6655

Various self-cleaving ribozymes appearing in nature catalyze the sequence-specific intramolecular cleavage of RNA and can be engineered to catalyze cleavage of appropriate substrates in an intermolecular fashion, thus acting as true catalysts. The mechanisms of the small, self-cleaving ribozymes have been extensively studied and reviewed previously. Self-cleaving ribozymes can possess high catalytic activity and high substrate specificity; however, substrate specificity is also engineerable within the constraints of the ribozyme structure. While these ribozymes share a common fundamental catalytic mechanism, each ribozyme family has a unique overall architecture and active site organization, indicating that several distinct structures yield this chemical activity. The multitude of catalytic structures, combined with some flexibility in substrate specificity within each family, suggests that such catalytic RNAs, taken together, could access a wide variety of substrates. Here, we give an overview of 10 classes of self-cleaving ribozymes and capture what is understood about their substrate specificity and synthetic applications. Evolution of these ribozymes in an RNA world might be characterized by the emergence of a new ribozyme family followed by rapid adaptation or diversification for specific substrates., Self-cleaving ribozymes have become important tools of synthetic biology. Here we summarize the substrate specificity and applications of the main classes of these ribozymes.

Laboratory evolution of functional RNAs has applications in many areas of chemical and synthetic biology. In vitro selections critically depend on the presence of functional molecules, such as aptamers and ribozymes, in the starting sequence pools. For selection of novel functions the pools are typically transcribed from random-sequence DNA templates, yielding a highly diverse set of RNAs that contain a multitude of folds and biochemical activities. The phenotypic potential, the frequency of functional RNAs, is very low, requiring large complexity of starting pools, surpassing 1015 different sequences, to identify highly active isolates. Furthermore, the majority of random sequences is not structured and has a high propensity for aggregation; the in vitro selection process thus involves not just enrichment of functional RNAs, but also their purification from aggregation-prone "free-riders". We reasoned that purification of the nonaggregating, monomeric subpopulation of a random-sequence RNA pool will yield pools of folded, functional RNAs. We performed six rounds of selection for monomeric sequences and show that the enriched population is compactly folded. In vitro selections originating from various mixtures of the compact pool and a fully random pool showed that sequences from the compact pool always dominate the population once a biochemical activity is detectable. A head-to-head competition of the two pools starting from a low (5 × 1012) sequence diversity revealed that the phenotypic potential of the compact pool is about 1000-times higher than the fully random pool. A selection for folded and monomeric RNA pools thus greatly increases the frequency of functional RNAs from that seen in random-sequence pools, providing a facile experimental approach to isolation of highly active functional RNAs from low-diversity populations.

The goal of the present work is to evaluate mechanical properties and to analyse the microstructure of 316L stainless steel produced by Laser Powder Bed Fusion (L-PBF) follow by rolling with different thickness reduction under ambient and cryogenic conditions. The samples before rolling were heat treated. The static tensile test was realized at ambient and cryogenic (77K) conditions. The L-PBF powder metal production technology approved that is a key technology in the AM area, especially for metal powder materials. Mechanical properties tested at 298K and 77K shows that the application of various thermo-deformation rolling conditions increases of strength properties. Achieved mechanical properties are comparable to conventional bulk materials. The strength properties after the rolling under ambient and cryogenic conditions were significantly increased.

The SARS-CoV-2 pandemic has brought to light the need for expedient diagnostic testing. Cost and availability of large-scale testing capacity has led to a lag in turnaround time and hindered contact tracing efforts, resulting in a further spread of SARS-CoV-2. To increase the speed and frequency of testing, we developed a cost-effective single-tube approach for collection, denaturation, and analysis of clinical samples. The approach utilizes 1 µL microbiological inoculation loops to collect saliva, sodium dodecyl sulfate (SDS) to inactivate and release viral genomic RNA, and a diagnostic reaction mix containing polysorbate 80 (Tween 80). In the same tube, the SDS-denatured clinical samples are introduced to the mixtures containing all components for nucleic acids detection and Tween 80 micelles to absorb the SDS and allow enzymatic reactions to proceed, obviating the need for further handling of the samples. The samples can be collected by the tested individuals, further decreasing the need for trained personnel to administer the test. We validated this single-tube sample- to-assay method with RT-qPCR and RT-LAMP and discovered little-to-no difference between Tween- and SDS-containing reaction mixtures, compared to CDC-approved reagents. This approach significantly reduces the logistical burden of traditional large-scale testing and provides a method of deployable point-of-care diagnostics to increase testing frequency.

Microbial sulphur cycle in sewers evocate the serious problem in the area concrete corrosion, health related aspects and odour.These problems are primarily related to the release of bacterially produced hydrogen sulphide from wastewater to the atmosphereduring sewage transports that dissolves in the condensate on the sewer crown. In the event sulphur-oxidizing bacteria oxidize thedissolved hydrogen sulphide and other sulphur compounds to sulphuric acid, which corrodes the concrete. The concrete graduallyexpands causing cracks and ruptures, loss of strength and overall decay of concrete.The paper is focused on the investigation of the concrete specimens surface biodegradation study. From the viewpoint of concretematerials biodeterioration, mainly the bacteria sulphur- and sulphide-oxidising bacteria and sulphate-reducing bacteria areimportant and interesting. The role of bacteria mentioned above has been linked to the generation of the biogenic sulphuric acidresulting in corrosion process by dissolution of calcium containing minerals from the concrete matrices. The penetration of thecorrosion was manifested by structural changes of concrete samples. The surface structure changes were by stereomicroscopy andatomic force microscopy (AFM) investigated.

This experimental study focuses on the assessment of mineral additives and their incorporation into cement composites (CC). The assessment was based on a holistic approach to the performance of the durability properties of CC. Environmental suitability was also taken into consideration. In the experiments, cement pastes with w/c ratios of 0.3, 0.4, and 0.5, respectively, were prepared. Natural zeolite (NZ) and densified silica fume (SF) at doses of 7.5 and 15.0 wt.% of cement were used as the investigated (replacement) materials. Their effects (including development over time) on density, strength (flexural and compressive), porosity by water absorption, permeability by rapid chloride penetration (RCP) test, phase content by thermal analysis, and hydration progression, were observed. The results were then used to propose an evaluation approach. Natural zeolite was used for its known pozzolanic activity and classification as a supplementary cementitious material (SCM). In contrast SF acted as a filler in cement pastes, and thus did not have a direct positive effect on durability. The concept of comprehensive analysis for unknown additive classification is proposed to expressly differentiate between SCM, inert, and improving mineral additive. This concept could be applied to the assessment of mineral additives with regards to the durability and suitability of cement composites.

A self-cleaving ribozyme mapping to an intron of the cytoplasmic polyadenylation element binding protein 3 (CPEB3) gene has been suggested to play a role in human episodic memory, but the underlying mechanisms mediating this effect are not known. The ribozyme’s self-scission half-life matches the time it takes an RNA polymerase to reach the immediate downstream exon, suggesting that the ribozyme-dependent intron cleavage is tuned to co-transcriptional splicing of the CPEB3 mRNA. Here we report that the murine ribozyme modulates its own host mRNA maturation in both cultured cortical neurons and the hippocampus. Inhibition of the ribozyme using an antisense oligonucleotide leads to increased CPEB3 protein expression, which enhances polyadenylation and translation of localized plasticity-related target mRNAs, and subsequently strengthens hippocampal-dependent long-term memory. These findings reveal a previously unknown role for self-cleaving ribozyme activity in regulating experience-induced co-transcriptional and local translational processes required for learning and memory.

RNA molecules can be conveniently synthesized in vitro by the T7 RNA polymerase (T7 RNAP). In some experiments, such as cotranscriptional biochemical analyses, continuous synthesis of RNA is not desired. Here, we propose a method for a single-pass transcription that yields a single transcript per template DNA molecule using the T7 RNAP system. We hypothesized that stalling the polymerase downstream from the promoter region and subsequent cleavage of the promoter by a restriction enzyme (to prevent promoter binding by another polymerase) would allow synchronized production of a single transcript per template. The single-pass transcription was verified in two different scenarios: a short self-cleaving ribozyme and a long mRNA. The results show that a controlled single-pass transcription using T7 RNAP allows precise measurement of cotranscriptional ribozyme activity, and this approach will facilitate the study of other kinetic events.

Each acid mine drainage has a specific composition, but always contains sulphuric acid, dissolved heavy metals, sulphates, iron precipitates and their pH can be very low. The elimination of metals form the acid mine drainage is a severe environmental problem andhas been a long-standing major concern to scientists, engineers, industry and governments. Various methods are used for the metalsremoval from waters, but any of them have been applied under commercial-scale conditions. Mostly studied are chemical and biological-chemical methods. Main aim of the paper was to interpret the combination of chemical and biological-chemical methods for theheavy metals elimination from the synthetic solution of acid mine drainage, coming from the zinc mine located in Tùnel Kingsmilloutlet of the Rio Yaulì (district of Yauli – Perù). The metals selective precipitation as hydroxides (chemical method) and sulphides(biological-chemical method) at the various values of pH acid mine drainage is the fundamental of the examined process. For thehydrogen sulphide production the sulphate-reducing bacteria of genus Desulfovibrio was used. The selective sequential precipitationprocess reaches the selective precipitation of chosen metals with 97–99% efficiency – Fe, As, Al and Mn in the form of metal hydroxides,Cu and Zn as metal sulphides

Self-cleaving ribozymes are RNA molecules that catalyze a site-specific self-scission reaction. Analysis of self-cleavage is a crucial aspect of the biochemical study and understanding of these molecules. Here we describe a co-transcriptional assay that allows the analysis of self-cleaving ribozymes in different reaction conditions and in the presence of desired ligands and/or cofactors. Utilizing a standard T7 RNA polymerase in vitro transcription system under limiting Mg

he poverty business has recently become a frequent issue in public discourse. The Program Declaration of the Government of the Czech Republic also reflects this, as the poverty business is mentioned here in relation to the abuse of the welfare system through overpriced lodging houses. In spite of the political significance oft he poverty business, the research on this issue has been scant. No attempt has even been made to clarify the meaning of this concept. This study is meant to be a first step in understanding the poverty business in the Czech context; it aims to explore how this phenomenon was represented in the Czech news media. The research was based on the theory of representation and qualitative content analysis, a method that was devised for thematic analysis of media content. The data were drawn from the Ano press IT database. Out of 1,277 texts containing the term “poverty business” and similar relevant terms, 66 texts were selected for the analysis. The analysis found that the poverty business is mainly presented as a matter of housing; however, other meanings were also identified, all of which were connected to the idea of exploitation of the poor and vulnerable segments of society. The victims of the poverty business include not only the clients of poverty entrepreneurs but also other people who were categorized according to their alleged decency or indecency. The consequences of the poverty business were seen as relating to clients, interethnic coexistence and the public administration. The main subjects identified in media communications were the state, municipality, and poverty entrepreneurs, who played the role of culprits, profiting subjects, and rectifiers. To conclude, the poverty business was represented asa highly politicized issue that concerns the misuse of housing benefits and is seen both as a socio-economic and ethno-cultural problem. The solution to the poverty business was mostly conceived as a technical intervention in to the welfare system, ignoring the agency of the victims of the poverty business.

Poverty business has become an important metaphor in the current debate regarding security in socially excluded localities. The term poverty business covers a range of business practices aimed at the poorest and most vulnerable populations. The goal of this study is to examine media representations of the phenomenon using content analysis of quantitative and qualitative data. First, characteristics of Czech media messages including the term “poverty business” are analysed. Next, key events are identified which have shaped the way poverty business is reported on in the analysed corpus. Finally, topics, groups and key actors are analysed based on the development of their quantitative representation in the corpus over time.

This work deals with comparing the mechanical properties of OFHC copper and CuCrZr alloys processed by asymmetric ambient rolling (ASaR) and asymmetric cryorolling (AScR). The conditions for asymmetrical rolling were ensured by different diameters of the main rolls. The thickness of samples was reduced about 20% - 70% at ambient temperature and at a temperature of liquid nitrogen. Mechanical properties such as yield strength, tensile strength, reduction of area and microhardness were determined for all rolled samples. Rolling at cryogenic temperatures provide about 50-60MPa more tensile strength for Cu and 60-80 MPa for CuCrZr alloys when rolling at ambient temperature. After AScR of CuCrZr alloys, a start of precipitation was shifted at the temperature of 434∘C and recrystallization was a part of the precipitation peak. According to the results, plastic deformation through shear bands is the dominant mechanism in materials with lower stacking fault energy (CuCrZr) treated under cryogenic conditions.

Hepatitis delta virus (HDV)-like ribozymes are self-cleaving catalytic RNAs with a widespread distribution in nature and biological roles ranging from self-scission during rolling-circle replication in viroids to co-transcriptional processing of eukaryotic retrotransposons, among others. The ribozymes fold into a double pseudoknot with a common catalytic core motif and highly variable peripheral domains. Like other self-cleaving ribozymes, HDV-like ribozymes can be converted into trans-acting catalytic RNAs by bisecting the self-cleaving variants at non-essential loops. Here we explore the trans-cleaving activity of ribozymes derived from the largest examples of the ribozymes (drz-Agam-2 family), which contain an extended domain between the substrate strand and the rest of the RNA. When this peripheral domain is bisected at its distal end, the substrate strand is recognized through two helices, rather than just one 7 bp helix common among the HDV ribozymes, resulting in stronger binding and increased sequence specificity. Kinetic characterization of the extended trans-cleaving ribozyme revealed an efficient trans-cleaving system with a surprisingly high K

Self-cleaving ribozymes were discovered 30 years ago and have been found throughout nature, from bacteria to animals, but little is known about their biological functions and regulation, particularly how cofactors and metabolites alter their activity. A hepatitis delta virus-like self-cleaving ribozyme maps upstream of a phosphoglucosamine mutase (glmM) open reading frame in the genome of the human gut bacterium Faecalibacterium prausnitzii. The presence of a ribozyme in the untranslated region of glmM suggests a regulation mechanism of gene expression. In the bacterial hexosamine biosynthesis pathway, the enzyme glmM catalyzes the isomerization of glucosamine 6-phosphate into glucosamine 1-phosphate. In this study, we investigated the effect of these metabolites on the co-transcriptional self-cleavage rate of the ribozyme. Our results suggest that glucosamine 6-phosphate, but not glucosamine 1-phosphate, is an allosteric ligand that increases the self-cleavage rate of drz-Fpra-1, providing the first known example of allosteric modulation of a self-cleaving ribozyme by the substrate of the adjacent gene product. Given that the ribozyme is activated by the glmM substrate, but not the product, this allosteric modulation may represent a potential feed-forward mechanism of gene expression regulation in bacteria.