Different Methods For Generation Research Articles

Induced pluripotent stem cells: Generation methods and a new perspective in COVID-19 research.

Induced pluripotent stem cells (iPSCs) exhibit an unlimited ability to self-renew and produce various differentiated cell types, thereby creating high hopes for both scientists and patients as a great tool for basic research as well as for regenerative medicine purposes. The availability and safety of iPSCs for therapeutic purposes require safe and highly efficient methods for production of these cells. Different methods have been used to produce iPSCs, each of which has advantages and disadvantages. Studying these methods would be very helpful in developing an easy, safe, and efficient method for the generation of iPSCs. Since iPSCs can be generated from somatic cells, they can be considered as valuable cellular resources available for important research needs and various therapeutic purposes. Coronavirus disease 2019 (COVID-19) is a disease that has endangered numerous human lives worldwide and currently has no definitive cure. Therefore, researchers have been rigorously studying and examining all aspects of COVID-19 and potential treatment modalities and various drugs in order to enable the treatment, control, and prevention of COVID-19. iPSCs have become one of the most attractive and promising tools in this field by providing the ability to study COVID-19 and the effectiveness of drugs on this disease outside the human body. In this study, we discuss the different methods of generation of iPSCs as well as their respective advantages and disadvantages. We also present recent applications of iPSCs in the study and treatment of COVID-19.

Rate constants for the reaction of SO with NO2 over the temperature range 220–960 K

AbstractThe kinetics of the reaction of SO radicals with NO2 have been studied in a discharge flow reactor combined with an electron impact ionization quadrupole mass spectrometer at nearly 2 Torr total pressure of helium and in the temperature range 220–960 K. The reaction rate constant was determined under pseudo‐first order conditions in excess of NO2 over SO using two different methods for generation of the SO radicals: k1 = (6.7 ± 0.2) × 10−12 exp(295 ± 10)/T) cm3 molecule−1 s−1 (the uncertainties represent precision at the 2σ level, the estimated total uncertainty on the rate constant being 15% at all temperatures). The present measurements indicate that the current recommendations for k1 underestimate the rate constant at low stratospheric temperatures and overestimate it at the high temperatures characteristic of combustion.

Effects of operational taxonomic unit inference methods on soil microeukaryote community analysis using long-read metabarcoding.

Long amplicon metabarcoding has opened the door for phylogenetic analysis of the largely unknown communities of microeukaryotes in soil. Here, we amplified and sequenced the ITS and LSU regions of the rDNA operon (around 1500 bp) from grassland soils using PacBio SMRT sequencing. We tested how three different methods for generation of operational taxonomic units (OTUs) effected estimated richness and identified taxa, and how well large‐scale ecological patterns associated with shifting environmental conditions were recovered in data from the three methods. The field site at Kungsängen Nature Reserve has drawn frequent visitors since Linnaeus's time, and its species rich vegetation includes the largest population of Fritillaria meleagris in Sweden. To test the effect of different OTU generation methods, we sampled soils across an abrupt moisture transition that divides the meadow community into a Carex acuta dominated plant community with low species richness in the wetter part, which is visually distinct from the mesic‐dry part that has a species rich grass‐dominated plant community including a high frequency of F. meleagris. We used the moisture and plant community transition as a framework to investigate how detected belowground microeukaryotic community composition was influenced by OTU generation methods. Soil communities in both moisture regimes were dominated by protists, a large fraction of which were taxonomically assigned to Ciliophora (Alveolata) while 30%–40% of all reads were assigned to kingdom Fungi. Ecological patterns were consistently recovered irrespective of OTU generation method used. However, different methods strongly affect richness estimates and the taxonomic and phylogenetic resolution of the characterized community with implications for how well members of the microeukaryotic communities can be recognized in the data.

МЕТОДИ ГЕНЕРАЦІЇ ЗАВДАНЬ ДЛЯ ОЦІНЮВАННЯ ЗНАНЬ

The article considers different methods of generation of test assignments . Their characteristics and their shortcomings were provided. Based on the shortcomings of other methods, the optimal method of the tests’ generation is chosen in the form of an online exam system with a test generator function. The article describes various requirements for the test assignments including possible types of tests, questions and tasks. The high relevance of the online exam systems is identified, as well as an analysis of its advantages and disadvantages. A comparison of characteristics of the existing systems of online examination is carried out, the basic parameters of these systems and differences between them are defined. Based on this comparison, the essential components of the system and the stages of its creation were identified. The article provides description of each component/module, the functions it performs, as well as the relationship between the modules. Also described are technologies, with which the system will be developed, and reasons for their selection. This system is developed with the server programming language PHP and MySQL database. The structure of the database is given in the article. A description of the most important database tables and their parameters is given. The article identifies different users roles within the system, their capabilities and functions in each module. It also presents their relationships in the form of UML diagrams and describes access levels by roles. The system will assist teachers with the process of generating assignments for various tests or exams. It will also facilitate educational monitoring of each student, identify their learning strengths and weaknesses, and assess their level of knowledge, thus saving teachers’ and students’ time. The teacher will only need to specify the necessary parameters for the test generation application, and the system itself will generate the appropriate assignments with the relevant tasks. The system will also allow students to take a test or exam from any device anywhere. The possible further improvements of the system are described, as well as potential issues that would have to be considered and addressed in the future.

COMPARISON OF DIFFERENT METHODS FOR GENERATION AND ABSORPTION OF WATER WAVES

The knowledge of water wave characteristics (generation, propagation, transformation and breaking) is fundamental for hydrodynamic studies and the design of ocean, coastal and port structures. In addition to the small-scale experimental studies, the use of numerical models is also a very important tool in hydrodynamic studies. To have reliable numerical results a proper validation is required. The main objective of this paper is to compare different methods of wave generation and wave absorption in a numerical flume, and to find what is the most suited to simulate non-breaking regular wave propagation in a two-dimensional flume in deep water condition. The numerical simulations were made using the OpenFOAM® software package. Two solvers, waves2Foam and IHFoam/OlaFlow, the utility GroovyBC and a mesh stretching technique are compared. These numerical codes solve the transient Navier-Stokes equations and use a VoF (Volume of Fluid) method to identify the free surface. A solution dependence study with the methods of wave generation and wave absorption is presented. The results are also compared with the theoretical wave and experimental data. The results show that the different methods of generation produce waves similar to the theoretical and the experimental ones, only slightly differences were visible. The three method of wave dissipation considered produce very different results: IHFoam/OlaFlow is not able to dissipate the wave tested; the mesh stretching technique is able to dissipate the waves but produces a water level rise; the waves2Foam solver is able to dissipate properly the wave tested.

Plasma-chemical formation of silver nanodispersion in water solutions

The application of plasma discharges of different methods of generation is an innovative, environmentally safe and promising method of synthesizing silver nanodispersions. The efficiency of using the contact nonequilibrium low-temperature plasma in comparison with the conventional method of chemical reduction in solutions and photochemical deposition is investigated. Plasma-chemical synthesis of silver nanodispersions from water AgNO 3 solutions without the use of additional reducing reagents and in the presence of sodium alginate stabilizing reagent is carried out. It is found that the yield of silver nanoparticles in the plasma-chemical synthesis is 95.10–97.17 %. The obtained data are obtained by the chemical reduction method in solutions (93.9 %) and photochemical deposition (20.0 %). It is found that in the plasma-chemical synthesis of silver nanodispersions, the introduction of sodium alginate into the reaction mixture increases the yield of silver nanoparticles and allows synthesizing stable colloidal silver solutions. It is shown that the formation of silver nanodispersions under plasma discharge is characterized by the presence of the peak λ max =400–420 nm. The formation of silver nanoparticles was confirmed by the X-ray diffraction analysis. Microscopic examination (SEM) indicates that the size of the formed silver particles is up to 100 nm. The mechanism of synthesizing silver nanoparticles in the sodium alginate solution under plasma discharge is proposed. The obtained data testify to the promising application of the nonequilibrium plasma for the controlled synthesis of silver nanodispersions and the need for further research in this direction

Microscale Characterization of Field and Laboratory Foamed Cement by Use of X-Ray Microcomputed Tomography

Summary Foamed-cement systems are widely used in deepwater-cementing operations because of their various favorable attributes compared with conventional cement systems. For instance, in the Gulf of Mexico, foamed cement is one of the most commonly used systems for shallow-hazard mitigation. However, because current standard laboratory equipment cannot accurately simulate the foam-cementing process in the field, knowledge of the actual properties of foamed cement produced in field operations is limited. In this study, the microstructure of foamed cement produced by use of field equipment in yard tests is examined in detail. Set foamed-cement samples were analyzed by use of X-ray microcomputed tomography (micro-CT) at different length scales with voxel resolution ranging from 2 to 20 µm. This study establishes the fundamental criteria and procedures necessary to obtain accurate gas-bubble-size distribution of foamed-cement samples by use of micro-CT technology. The test results suggest that foamed cement should be analyzed at multiple length scales to obtain a better characterization of the gas bubbles in the sample. Although a larger region of analysis is useful to obtain a statistically meaningful size distribution of the larger bubbles, small core samples (diameter smaller than 0.5 in.) and fine scan resolutions (5 µm or smaller) are typically required to obtain an accurate measure of the small gas bubbles in foamed cement. By comparing foamed cement produced by use of field equipment with that produced by use of the traditional multiblade laboratory blender—i.e., the standard American Petroleum Institute (API) method—this study identifies the key characteristic differences of foamed cement derived from different methods of generation. Analysis of the CT-scan images reveals that gas bubbles in foamed cement generated by field equipment approximately follows a log-normal distribution with a wide size-distribution range, from less than 20 µm to more than 1000 µm, and the bubble-size distribution appears to show little dependence on foam quality. Conversely, the gas-bubble-size distribution of foamed cement generated by the API method shows a completely different behavior. It approximately follows a Gaussian distribution, with both distribution range and median varying significantly with foam quality. This research serves as a first step toward predicting the influence of gas-bubble-size distribution on the stability and various other properties of foamed cement to better understand the foam-cementing process in the field.

Comparison of different methods for generation of single-stranded DNA for SELEX processes

Single-stranded DNA (ssDNA) generation is a crucial step in several molecular biology applications, such as sequencing or DNA chip and microarray technology. Molecules of ssDNA also play a key role in the selection of ssDNA aptamers through Systematic Evolution of Ligands by EXponential enrichment (SELEX). With particular interest for this application, herein we present a comparative study of the most used methods for generation of ssDNA used in SELEX, such as asymmetric PCR, enzyme digestion and magnetic separation with streptavidin beads. In addition, we evaluate a new technique that combines asymmetric PCR and enzyme digestion with the aim to achieve the maximum efficiency in ssDNA generation. The methods studied were compared in terms of quality of ssDNA using electrophoretic analysis and generated ssDNA yields were quantitatively measured using an Enzyme-Linked OligoNucleotide Assay (ELONA).

Numerical simulation of the strain inhomogeneities during plain strain compression on the basis of the digital material representation

This work is part of the research focused on the creation of the complex modelling platform called Digital Material Representation (DMR). The main objective of the DMR system is development of the digital representation of microstructure with its features, such as grains, grain orientations, inclusions, cracks, different phases etc. represented explicitly. The idea of the DMR system containing different methods of generation of digital microstructures, assigning properties and mesh generation, is described. Numerical simulation of the plain strain compression test on the basis of the DMR are the main objective of this work. Particular attention is paid to on inhomogenous strain evolution and its relations with underlying microstructure. Advantages and limitations of this methodology in comparisons with the conventional approaches are discussed, as well.

Identification of discriminative characteristics for clusters from biologic data with InforBIO software.

BackgroundThere are a number of different methods for generation of trees and algorithms for phylogenetic analysis in the study of bacterial taxonomy. Genotypic information, such as SSU rRNA gene sequences, now plays a more prominent role in microbial systematics than does phenotypic information. However, the integration of genotypic and phenotypic information for polyphasic studies is necessary for the classification and identification of microbes. Thus, we devised an algorithm that objectively identifies discriminative characteristics for focused clusters on generated trees from a dataset composed of coded data, such as phenotypic information. Moreover, this algorithm has been integrated into the polyphasic analysis software, InforBIO.ResultsWe developed a differential-character-finding algorithm based on information measures and used this algorithm to identify the characteristic that best discriminates operational taxonomic unit clusters. For all characteristics in a dataset, the algorithm estimates commonality in focused clusters and diversity among clusters by scoring based on Shannon's and relative entropies. All the characteristics selected for scoring are equally weighted. Thresholds for the scores are defined to identify discriminative characteristics for clusters efficiently from a database. The unique feature of the algorithm, which is implemented in the InforBIO software, is that it can identify the phenotypic characteristics that discriminate and are associated with the clusters of a phylogenetic tree. We successfully applied this algorithm to the study of phylogenetic clusters of Pseudomonas species.ConclusionThe algorithm in the InforBIO software is a novel and useful approach for microbial polyphasic studies. The algorithm can also be applied to diverse cluster analyses. The InforBIO software is available from the download site . This software is free for personal but not commercial use.

Farey codes and languages

A word w is central if it has a minimal period π w such that | w | − π w + 2 is a period of w coprime with π w . Central words are in a two-letter alphabet A and play an essential role in combinatorics of Sturmian words. We study some new structural properties of the set PER of central words which are based on the existence of two basic bijections ψ and φ of A ∗ in PER , related to two different methods of generation, and two natural bijections θ (the ratio of periods) and η (the rate) of PER in the set of all positive irreducible fractions. In this paper we are mainly interested in sets of central words which are codes. In particular, for any positive integer n we consider the set Δ n of all central words w such that the period | w | − π w + 2 is not larger than n + 1 and | w | ≥ n . In a previous paper we proved that for each n , Δ n is a maximal prefix central code called the Farey code of order n since it is naturally associated with the Farey series of order n + 1 . New structural properties of Farey codes are given as well as of their pre-codes P n . In particular one has PER = ∪ n ≥ 0 Δ n . Moreover, for each n two languages of central words L n and M n are introduced. The language L n (resp., M n ) is called the Farey (resp., dual Farey) language of order n . The name is motivated by the fact that L n and M n give faithful representations of the set of Farey’s fractions of order n . Finally, two total orderings of PER are naturally defined in terms of maps θ and η . The notion of order of a central word relative to a language of central words is given and some general results are proved. In the case of Farey’s languages one has that the Riemann hypothesis on the Zeta function can be restated in terms of a combinatorial property of these languages.

Properties and methods of calculating generalised arithmetic and adding transforms

The methods of generation of forward and inverse transformation kernels for generalised arithmetic and adding transforms are presented. Different methods of generation of transformation matrices or spectra in arbitrary polarities from a known transformation matrix or spectrum in some polarity have been developed. Using an optimised dyadic convolution process on the original data vector, a new method with a reduced number of operations is shown to calculate the generalised arithmetic and adding spectra. The properties and efficient ways of generation of permutation matrices used in the generation of arithmetic and adding transforms have been investigated. Based on the representation of transform matrices in the form of layered Kronecker matrices, a unified approach to the fast algorithms in terms of strand matrices has been developed. The computational complexities in the evaluation of arithmetic and adding spectral coefficients of an arbitrary order z and orders up to some z have been given.

The influence of depairing on charge imbalance in nonequilibrium superconductivity

Abstract The effect of pair-breaking on a spatially uniform charge imbalance is considered for different methods of generation. The magnitude of the charge imbalance is calculated as a function of temperature for a variety of depairing mechanisms in both the clean and dirty limits as well as in between.