solution processing
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2nd ed. xviii, 826 s. : il. ; 25 cm
- MeSH
- diagnostické zobrazování MeSH
- počítačové zpracování obrazu MeSH
- Publikační typ
- příručky MeSH
- Konspekt
- Speciální počítačové metody. Počítačová grafika
- NLK Obory
- lékařská informatika
Tento článek popisuje vybrané problémy v oblasti elektroencefalografi e, současné přístupy k jejich řešení a trendy vývoje a výzkumu. Stručně jsou popsány metody počítačové klasifi kace EEG záznamů a eliminace artefaktů v nich. Dále následuje několik pokročilejších metod zpracování a praktického využití EEG, mezi něž patří teorie chaosu, analýza nezávislých komponent, skryté Markovovy modely, rozhraní mozek-počítač a EEG biofeedback. Na závěr je krátce pojednáno o přenosných EEG systémech malých rozměrů.
This paper describes selected problems in the area of electroencephalography, current approaches to their solution and trends in research and development. Methods of computer-assisted classifi cation and artifacts removing from EEG signals are briefl y mentioned. Th is paper also introduce several advanced methods of computer processing and practical use of EEG, namely Chaos theory, Independent Component Analysis, Hidden Markov models, Brain computer interface and EEG biofeedback. Small portable EEG systems are introduced at the end of paper.
- MeSH
- ambulantní monitorování metody přístrojové vybavení využití MeSH
- analýza hlavních komponent MeSH
- biomedicínské technologie přístrojové vybavení trendy MeSH
- časové faktory MeSH
- elektroencefalografie přístrojové vybavení trendy využití MeSH
- financování organizované MeSH
- fraktály MeSH
- lidé MeSH
- nelineární dynamika MeSH
- počítačové zpracování signálu přístrojové vybavení MeSH
- telemetrie metody přístrojové vybavení využití MeSH
- uživatelské rozhraní počítače MeSH
- zpětná vazba MeSH
- Check Tag
- lidé MeSH
Von Willebrand Factor (vWF), a 300-kDa plasma protein key to homeostasis, is cleaved at a single site by multi-domain metallopeptidase ADAMTS-13. vWF is the only known substrate of this peptidase, which circulates in a latent form and becomes allosterically activated by substrate binding. Herein, we characterised the complex formed by a competent peptidase construct (AD13-MDTCS) comprising metallopeptidase (M), disintegrin-like (D), thrombospondin (T), cysteine-rich (C), and spacer (S) domains, with a 73-residue functionally relevant vWF-peptide, using nine complementary techniques. Pull-down assays, gel electrophoresis, and surface plasmon resonance revealed tight binding with sub-micromolar affinity. Cross-linking mass spectrometry with four reagents showed that, within the peptidase, domain D approaches M, C, and S. S is positioned close to M and C, and the peptide contacts all domains. Hydrogen/deuterium exchange mass spectrometry revealed strong and weak protection for C/D and M/S, respectively. Structural analysis by multi-angle laser light scattering and small-angle X-ray scattering in solution revealed that the enzyme adopted highly flexible unbound, latent structures and peptide-bound, active structures that differed from the AD13-MDTCS crystal structure. Moreover, the peptide behaved like a self-avoiding random chain. We integrated the results with computational approaches, derived an ensemble of structures that collectively satisfied all experimental restraints, and discussed the functional implications. The interaction conforms to a 'fuzzy complex' that follows a 'dynamic zipper' mechanism involving numerous reversible, weak but additive interactions that result in strong binding and cleavage. Our findings contribute to illuminating the biochemistry of the vWF:ADAMTS-13 axis.
- MeSH
- kinetika MeSH
- lidé MeSH
- molekulární modely MeSH
- peptidy chemie MeSH
- posttranslační úpravy proteinů * MeSH
- protein ADAMTS13 metabolismus MeSH
- reagencia zkříženě vázaná chemie MeSH
- roztoky MeSH
- vazba proteinů MeSH
- von Willebrandův faktor chemie izolace a purifikace metabolismus MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
This paper brings a new rigorous and complete statistical approach to the data processing of the mobility curves of univalent weak bases. This approach is based on application of the least square method to the equation of the related mobility curve. Thus, an equation for the best fit is derived and its mathematical solution is found. The solution brings best estimates of the mobility curve parameters, i.e., dissociation constant K and ionic mobility of the protonated base U. Further, explicit formulas have been derived for the calculation of related statistical parameters, i.e., SDs of effective mobility s(u), of the dissociation constant s(K), and of ionic mobility of protonated base s(U). The mathematical functions used in the above approach do not impose any limitations on the data used, i.e., the mobility and pH values used may be real numbers (positive, negative, zero).
Fundamental operational principle and instrumental set-up of electromembrane extraction (EME) suggest that electrolysis may play an important role in this recently developed micro-extraction technique. In the present study, the effect of electrolysis in EME is described comprehensively for the first time and it is demonstrated that electrolysis considerably influences EME performance. Micro-electromembrane extraction (μ-EME) across free liquid membrane formed by 1-pentanol was utilized for real-time monitoring of the electrolytically induced changes in composition of μ-EME solutions. These changes were visualized with a set of acid-base indicators. Changes in colours of their aqueous solutions revealed serious variations in their pH values, which occurred within seconds to minutes of the μ-EME process. Variations of up to eight pH units were observed for indicator solutions initially prepared in 1, 5 and 10mM hydrochloric acid. No or only negligible pH changes (less than 0.15 pH unit) were observed for indicator solutions prepared in 50 and 100mM acetic acid demonstrating that initial composition of the aqueous solutions was the crucial parameter. These results were also confirmed by theoretical calculations of maximum pH variations in the solutions, which were based on total electric charge transfers measured in the μ-EME systems, and by exact measurements of their pH values after μ-EMEs. Acceptor solutions that, in the current practice, consist predominantly of low concentrations of strong mineral acids or alkali hydroxides may thus not always ensure adequate EME performance, which was manifested by decrease in extraction recoveries of a basic drug papaverine. A suitable remedy to the observed effects is the application of acceptor solutions containing high concentrations of weak acids or bases. These solutions not only eliminate the decrease in recoveries but also serve well as matrices of extracted samples for subsequent analysis by capillary electrophoresis.
Characteristics of inert starters in drug solution layering are important for successful active pellet formation. Four types of starters composed of sucrose or microcrystalline cellulose (MCC) or lactose and MCC were compared in our study. The active pellets were prepared using Wurster type apparatus. Yield and pellet quality parameters were determined. The highest yield (85.66-89.41%) was obtained for cores composed of MCC due to their insolubility in water (the drug solvent) and good mechanical properties. On the contrary, soluble and brittle sucrose cores dissolved partially during the process forming undesirable agglomerates and giving lower yield (76.2%). All pellet samples showed good flow properties and drug content from 82.4 to 94.5% of the theoretical drug amount.
V procese výskumu a vývoje liečiva má svoje nezastupiteľné miesto aj sledovanie stability liečiva, resp. lieku. V tomto príspevku je to potenciálne liečivo H+B, chemicky N-[2-(2-heptyloxyfenylkarbamoyloxy)-etyl]-N-benzylpipendiniumchlorid, s výrazným antiarytmickým a tiež lokálne anestetickým účinkom. Sledovala sa stabilita potenciálneho liečiva H+B v roztoku bez a v prítomnosti polyolov za účelom formulácie injekčného roztoku pre intramuskulámu aplikáciu.
In the process of drug research and development an irreplaceable stage is the examination of stability of the drug or the pharmaceutical preparation. The present paper examines the potential drug H+B, chemically N-[2-(2-heptyloxyphenylcarbamoyloxy)-ethyl]-N-benzylpiperidinium chloride, an agent with a marked anti-arrhytmic and local anaesthetic effect. Stability tests aim to examine the effects of polyols on the stability of the potential drug H+B from the standpoint of the formulation of injection solution for intramuscular administration.
