Anionic capillary isotachophoresis (ITP) with conductimetric detection has been used for determining selected non-steroid anti-inflammatory and analgesic drugs of the phenamate group, namely ...tolfenamic (
I), flufenamic (
II), mefenamic (
III) and niflumic (
IV) acid. Initially the p
K
a values (proton lost) of
I–
IV were determined as 5.11, 4.91, 5.39 and 4.31, respectively, by the UV spectrophotometry in aqueous 50% (w/w) methanol. The optimised ITP electrolyte system consisted of 10 mM HCl+20 mM imidazole (pH 7.1) as the leading electrolyte and 10 mM 5,5′-diethylbarbituric acid (pH 7.5) as the terminating electrolyte. The driving and detection currents were 100 μA (for 450 s) and 30 μA, respectively (a single analysis took about 20 min). Under such conditions the effective mobilities of
I–
IV varied between 23.6 and 24.6 m
2 V
−1 s
−1 (evaluated with orotic acid as the mobility standard). The calibration graphs relating the ITP zone length to the concentration of the analytes were rectilinear (
r=0.9987–0.9999) in the range 10–100 mg l
−1 of the drug standard. The R.S.D.s were 0.96–1.55% (
n=6) when determining 50 mg l
−1 of the analytes in pure test solutions. The method has been applied to the assay of the phenamates in six commercial mass-produced pharmaceutical preparations (Mobilisin gel and ointment, Lysalgo capsules, Nifluril cream, Niflugel gel, and Clotam capsules). According to the validation procedure based on the standard addition technique the recoveries were 98.4–104.3% of the drug and the R.S.D. values were 1.25–3.32% (
n=6).
Polycystic ovary syndrome (PCOS) affects 5% of reproductive aged women and is the leading cause of anovulatory infertility. A hallmark of PCOS is excessive theca cell androgen secretion, which is ...directly linked to the symptoms of PCOS. Our previous studies demonstrated that theca cells from PCOS ovaries maintained in long term culture persistently secrete significantly greater amounts of androgens than normal theca cells, suggesting an intrinsic abnormality. Furthermore, previous studies suggested that ovarian hyperandrogenemia is inherited as an autosomal dominant trait. However, the genes responsible for ovarian hyperandrogenemia of PCOS have not been identified. In this present study, we carried out microarray analysis to define the gene networks involved in excess androgen synthesis by the PCOS theca cells in order to identify candidate PCOS genes. Our analysis revealed that PCOS theca cells have a gene expression profile that is distinct from normal theca cells. Included in the cohort of genes with increased mRNA abundance in PCOS theca cells were aldehyde dehydrogenase 6 and retinol dehydrogenase 2, which play a role in all-trans-retinoic acid biosynthesis and the transcription factor GATA6. We demonstrated that retinoic acid and GATA6 increased the expression of 17α-hydroxylase, providing a functional link between altered gene expression and intrinsic abnormalities in PCOS theca cells. Thus, our analyses have 1) defined a stable molecular phenotype of PCOS theca cells, 2) suggested new mechanisms for excess androgen synthesis by PCOS theca cells, and 3) identified new candidate genes that may be involved in the genetic etiology of PCOS.
The review describes principles of procedures and techniques used in capillary zone electrophoresis for enhancement of sensitivity that are based on increasing analyte mass in its zone during the ...electromigration process, for which the term stacking is generally used. Attention is paid to intrinsic stacking in samples with low conductivity, transient isotachophoretic stacking applied in samples with high conductivity, and sweeping in micellar electrokinetic chromatography. Principles of these stacking schemes are explained, new procedures and instrumental arrangements are discussed, and all contributions involving stacking principles that have been published since the year 2000 are surveyed.
The aim of this study is the evaluation of the parameters for the material model description in simulation of plasticity and fracture in shearing processes. The experimental measurements and the ...simulations are performed at room temperature for TWIP steel and 38MnVS6. The behaviour of materials is described using MARC/MENTAT and DEFORM software based on the finite element method. The material model is made up on the basis of tension test. The fracture criteria are based on the experimental failure during tension and torsion tests. The fracture models Normalized Cockcroft-Latham (NCL) and Oyane are used for subsequent simulation of shearing. The description of shearing comprises not only the initiation of a fracture but also the growth of the fracture until the material parts are separated. This issue is solved by means of two numerical methods, the softening and the element deletion.
Magnonics addresses the physical properties of spin waves and utilizes them for data processing. Scalability down to atomic dimensions, operation in the GHz-to-THz frequency range, utilization of ...nonlinear and nonreciprocal phenomena, and compatibility with CMOS are just a few of many advantages offered by magnons. Although magnonics is still primarily positioned in the academic domain, the scientific and technological challenges of the field are being extensively investigated, and many proof-of-concept prototypes have already been realized in laboratories. This roadmap is a product of the collective work of many authors that covers versatile spin-wave computing approaches, conceptual building blocks, and underlying physical phenomena. In particular, the roadmap discusses the computation operations with Boolean digital data, unconventional approaches like neuromorphic computing, and the progress towards magnon-based quantum computing. The article is organized as a collection of sub-sections grouped into seven large thematic sections. Each sub-section is prepared by one or a group of authors and concludes with a brief description of current challenges and the outlook of further development for each research direction.
. The best tool for characterizing the behaviour of sheet metal during press forming is numerical modelling based on the finite element method (FEM). Using this technique, the response of the ...press-formed part can already be predicted during the process design stage. The main input data for the process simulation include the tool geometry and materials properties and process conditions, such as temperature, pressing velocity, lubrication and others. The resultant shape of the press-formed part is governed predominantly by the shape of the tools and the workpiece material. The input information on the workpiece material has the form of a material model whose accuracy dictates the accuracy of results. Where high-strength steels are used in the automotive industry, one should focus on springback which alters the shape of press-formed parts. Springback is an undesirable change to the part's shape caused by residual stresses being released after its removal from the tool. Tooling designers need to take springback into account by choosing an appropriate material model. Conventional hardening models, such as kinematic and isotropic hardening rules, are not adequate for modelling springback. Instead, more sophisticated models, such as the one introduced by Lemaitre and Chaboche are a better choice. In this paper, the options for measuring and FE modelling of the Bauschinger effect are discussed. The proposed idea was tested on a 1.5 mm sheet of DC01 deep-drawing steel.
. This contribution is concerned with determining the edge strain in edges with different finish qualities associated with crack formation in the free edge of a deep drawing blank. The sheared edge ...quality is of major importance, particularly in high-strength steels which are used for safety components. The purpose of this study was to determine for various parting processes for sheet metal the limit strain which leads to cracking in the free edge. The parameter which was varied in this investigation was the parting process that produced the edge: shearing and machining. A special fixture was employed for measuring the strain value. The values were verified using FE modelling with AutoForm software. The surface finish qualities of the edges were compared using a special test procedure, the Diabolo test, which had been previously described in publications by Held 1 and Liewald and Gall 2. In this test, the sheared edge is subjected to loading under plane strain conditions. Another test of susceptibility to edge cracking is the hole expansion test 3, in which crack is induced in a circular hole in the centre of a part. The limit edge strain can be identified using a DIC optical measuring system which monitors strain increments in the course of the test. Thanks to these results, the factors which affect the susceptibility of the sheared edge to edge cracking material have been identified and validated in the DP1000 material.
The purpose of this paper is to assess the extent of gene identity and differentiation at 33 dinucleotide repeat loci (377 total alleles) within and among three European and three Native American ...populations. In order to do this, we show that a maximum-likelihood method proposed for phylogenetic trees (Cavalli-Sforza and Piazza 1975) can be used to estimate gene identity (Nei 1987) with respect to any hierarchical structure. This method allows gene differentiation to be evaluated with respect to any internal node of a hierarchy. It also allows a generalization of F- and G-statistics to situations with unequal expected levels of differentiation. Our principal finding is that levels of genetic differentiation are unique to specific populations and levels of nesting. The populations of European origin show very little internal differentiation; moreover, their continental average is close to the total population defined by the aggregate of Europeans and Native Americans. By contrast, the Native American populations show moderate levels of internal differentiation, and a great distance between their continental average and the total. The results of analyses of subsets of loci that were selected to have high gene diversities in either Europeans or Native Americans closely parallel those from the total set of loci. This suggests that the principal results are unlikely to be caused by a European ascertainment bias in locus selection. In summary, our findings demonstrate that partitions of gene diversity into within- and between-populations components are heavily biased by the populations analyzed and the models fitted. Optimistically, however, more information is available to analyze population history and evolution by quantifying, as we have done, the uniqueness of patterns of differentiation.
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