retention modeling
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The effect of practice schedule on retention and transfer has been studied since the first publication on contextual interference (CI) in 1966. However, strongly advocated by scientists and practitioners, the CI effect also aroused some doubts. Therefore, our objective was to review the existing literature on CI and to determine how it affects retention in motor learning. We found 1255 articles in the following databases: Scopus, EBSCO, Web of Science, PsycINFO, ScienceDirect, supplemented by the Google Scholar search engine. We screened full texts of 294 studies, of which 54 were included in the meta-analysis. In the meta-analyses, two different models were applied, i.e., a three-level mixed model and random-effects model with averaged effect sizes from single studies. According to both analyses, high CI has a medium beneficial effect on the whole population. These effects were statistically significant. We found that the random practice schedule in laboratory settings effectively improved motor skills retention. On the contrary, in the applied setting, the beneficial effect of random practice on the retention was almost negligible. The random schedule was more beneficial for retention in older adults (large effect size) and in adults (medium effect size). In young participants, the pooled effect size was negligible and statically insignificant.
- MeSH
- lidé MeSH
- motorické dovednosti * fyziologie MeSH
- retence (psychologie) fyziologie MeSH
- učení * fyziologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- metaanalýza MeSH
- systematický přehled MeSH
- MeSH
- inhalační expozice MeSH
- krysa rodu rattus MeSH
- magnetismus MeSH
- mangan toxicita MeSH
- modely nemocí na zvířatech MeSH
- mozek metabolismus MeSH
- potkani Wistar MeSH
- sloučeniny manganu metabolismus MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- zvířata MeSH
- Publikační typ
- přehledy MeSH
- srovnávací studie MeSH
In this work, we have investigated retention of maltooligosaccharides and their fluorescent derivatives in hydrophilic interaction liquid chromatography using four different stationary phases. The non-derivatized maltooligosaccharides (maltose to maltoheptaose) and their derivatives with 2-aminobenzoic acid, 2-aminobenzamide, 2-aminopyridine and 8-aminonaphthalene-1,3,6-trisulfonic acid were analyzed on silica gel, aminopropyl silica, amide (carbamoyl-bonded silica) and ZIC-HILIC zwitterionic sulfobetain bonded phase. The partitioning of the analytes between the bulk mobile phase and adsorbed water-rich layer, polar and ionic interactions of analytes with stationary phase have been evaluated and compared. The effects of the mobile phase additives (0.1% (v/v) of acetic acid and ammonium acetate in concentration range 5-30 mmol L(-1)) on retention were described. The suitability of different models for prediction of retention was tested including linear solvent strength model, quadratic model, mixed-mode model, and empirical Neue-Kuss model. The mixed-mode model was extended to the parameter describing the contribution of monomeric glucose unit to the retention of non-derivatized and derivatized maltooligosaccharides, which was used for evaluation of contribution of both, oligosaccharide backbone and end-group to retention.
- MeSH
- 1-naftylamin chemie MeSH
- adsorpce MeSH
- aminopyridiny chemie MeSH
- chemické modely * MeSH
- chemické techniky analytické * MeSH
- chromatografie kapalinová * MeSH
- hydrofobní a hydrofilní interakce MeSH
- oligosacharidy chemie izolace a purifikace MeSH
- ortoaminobenzoáty chemie MeSH
- oxid křemičitý chemie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Úvod: Od sedmdesátých let minulého století prošla inflatabilní penilní protéza (IPP) řadou zdokonalení. Zatímco při užívání prvních prototypů docházelo často k mechanickému selhání, dnešní modely jsou mnohem spolehlivější. Přestože výskyt komplikací spojených s rezervoárem není častý, pokud k podobné komplikaci dojde, obvykle způsobuje poškození okolní tkáně. Schopnost rozpoznat a léčit tyto komplikace je tedy nezbytná pro každého urologa, který protézy běžně implantuje. Cíl: Cílem tohoto článku je představit vzácně se vyskytující komplikaci související s rezervoárem a prezentovat výsledky průzkumu literatury zaměřeného na techniky implantace rezervoáru a s nimi spojených komplikací. Metody: Hodnotíme výskyt ojedinělé komplikace související s rezervoárem zaznamenané v našem centru, která se manifestovala močovou retencí a zácpou. Dále hodnotíme výskyt komplikací souvisejících s rezervoárem zaznamenaných od roku 1984 a nejnovější techniky užívané při implantaci rezervoáru penilní protézy. Hlavní výsledné parametry: Komplikace související s rezervoárem způsobující močovou retenci a zácpu. Výsledky: Ačkoli výskyt komplikací není častý, může v souvislosti s implantací penilní protézy docházet k problémům. Nejčastější komplikace zahrnují erozi močového měchýře s následnou kompresí zevní iliacké žíly, erozi ileálního konduitu a obstrukci tenkého střeva. Případ popsaný v našem centru byl způsoben nesprávným umístěním rezervoáru v perineu, jež vedlo v důsledku komprese bulbární části močové trubice a rekta k močové retenci a zácpě. Závěr: V dnešní době dochází k mechanickému selhání protézy pouze v naprosto výjimečných případech, většina komplikací vzniká v důsledku poškození okolní tkáně. Schopnost předcházet těmto komplikacím, diagnostikovat je a léčit je tedy nezbytná pro všechny urology, kteří běžně implantují penilní protézy.
Introduction: There have been many advances in the inflatable penile prosthesis (IPP) since the 1970's. While these devices were initially fraught with mechanical malfunction, the most recent models prove to be much more reliable. Although reservoir complications are not common, when they do occur it typically involves damage to the surrounding tissues. The ability to recognize and treat these complications is paramount for any surgeon that routinely places IPP's. Aim: The aim of this article is to present a unique reservoir-related complication as well as perform a literature review of reservoir related complications, and techniques for reservoir placement. Methods: We reviewed a unique reservoir–related complication that presented to our institution with urinary retention and constipation. We also reviewed reservoir-related complications since 1984 and reviewed the most recent surgical techniques involved in reservoir placement. Main Outcome Measures: A reservoir-related complication that resulted in urinary retention and constipation. Results: Although uncommon, reservoir complications do occur. The most common being bladder erosion followed by external iliac compression, ileal conduit erosion, and small bowel obstruction. The case that presented at our institution was the result of a reservoir that was improperly placed in the perineum, causing urinary retention and constipation due to the compression of the bulbar urethra and rectum. Conclusions: In this era, mechanical failure of IPP's are exceedingly rare as most complications occur due to damage of the surrounding tissues. Prevention, diagnosis, and treatment of these complications is important for any surgeon that implants IPP's.
- MeSH
- cystoskopie MeSH
- diverze moči MeSH
- hematurie MeSH
- ischemie diagnóza MeSH
- lidé MeSH
- miniinvazivní chirurgické výkony MeSH
- močový měchýř * patofyziologie MeSH
- neúspěšná terapie MeSH
- penilní protézy * škodlivé účinky MeSH
- penis * krevní zásobení patofyziologie MeSH
- počítačová rentgenová tomografie MeSH
- pooperační komplikace * diagnóza MeSH
- postup MeSH
- protetické vybavení MeSH
- retence moči MeSH
- selhání protézy MeSH
- senioři MeSH
- směrnice pro lékařskou praxi jako téma MeSH
- stenóza MeSH
- vény patofyziologie MeSH
- výsledek terapie MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- senioři MeSH
- Publikační typ
- kazuistiky MeSH
- přehledy MeSH
Seven retention models have been selected to describe a dual-retention behavior of ten dopamine-related compounds on polymer-based monolithic stationary phase with zwitterion sulfobetaine functionality. Regression quality, as well as a statistical significance of individual regression parameters, have been evaluated. Better regression performance showed two four-parameter models when compared to three-parameter models. On the other hand, limited number of experimental points disqualified statistical robustness of four-parameter models. Among three-parameter models, retention description introduced by Horváth and Liang provided comparable quality of regression at significantly improved robustness. Multivariate analysis of the best three-parameter models provided the description of physicochemical properties of dopamine precursors and metabolites. Principal component analysis and logistic regression allowed structural characterization of dopamine-related compounds based solely on regression parameters extracted from an isocratic elution data. Both polarity and type of functional groups has been correctly assigned for 3-methoxytyramine that has not been part of an evaluation study. Among applied dual-retention models, Horváth´s model, initially developed to describe a retention of ionic compounds on nonpolar stationary phases, provided robust regression of experimental data and allowed an extraction of structural characteristics of dopamine-related compounds.
The availability of ionic liquids (ILs) in wide areas of application often results in the requirement on their determination. The attention is also often focused on the knowledge of hydrophobicity as it plays a key role in the biological effects, in the assessment of environmental risk and in the prediction of the fate of chemicals in the environment and of its influence on retention in RP HPLC. One can get information regarding hydrophobicity and retention mechanism if quantitative structure-retention relationships (QSRRs) are identified. The QSRRs were derived for logarithms of retention factors extrapolated to a pure water (or aqueous buffer) eluent, log k(w), determined for the pyridinium and imidazolium ionic liquid (IL) cations on two C8 (Supelcosil LC-8-DB, Symmetry C8) and two C18 (ACE 5 C18, Symmetry C18) stationary phases with isocratic elution by a mobile phase consisting of acetonitrile/40 mM phosphate buffer. The analyses of ILs were performed at a flow rate of 1 mL min(-1) with UV detection at 218 nm. The QSRRs were derived based on the retention parameters determined experimentally and the structural descriptors of test analytes from molecular modeling. Separations of ILs were obtained with aqueous acetonitrile buffered at pH 3.55 mobile phases. The statistically most significant two-parameter QSRR regression equations related log k(w) to the solvent accessible surface (SAS) of the analytes and the differences in the energies of the highest occupied and the lowest unoccupied molecular orbitals (diffHL). These equations were especially good in case of columns with the highest carbon loads and larger specific surface areas, i.e. Symmetry C18 and Symmetry C8. On the other hand, the column ACE 5 C18 appeared to produce the best quality separations of the ILs studied. The QSRRs derived in the research shed light on the molecular mechanism of HPLC separation of ILs and helped to predict their relative separations.
- MeSH
- chemické modely MeSH
- chromatografie s reverzní fází metody MeSH
- hydrofobní a hydrofilní interakce MeSH
- iontové kapaliny chemie MeSH
- kationty chemie MeSH
- molekulární struktura MeSH
- vysokoúčinná kapalinová chromatografie metody MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
We studied possibilities of prediction of the gradient elution data for alkylbenzenes, flavones and phenolic acids on two short octadecyl silica gel monolithic columns, namely a Chromolith Flash C18, 25×4.6mm, and a "new generation" Chromolith High Resolution C18, 50×4.6mm, in fast 1-2min gradients. With fixed short gradient times and varying gradient ranges of acetonitrile concentration in water, high flow rates of the mobile phase (3-5mL/min) could be used. The gradient elution data were predicted from four gradient models based on two-parameter and three-parameter isocratic retention equations. Various gradient retention models can be used for prediction of chromatograms and optimization of separation within a fixed gradient time. A two-parameter log-log model introduced in 1974 and a three-parameter model introduced in 1980 provided slightly more accurate prediction than the Linear Solvent Strength (LSS) semi-logarithmic two-parameter model, most frequently used in reversed-phase LC. A three-parameter model introduced in 1978 provided slightly improved accuracy of prediction of gradient data with respect to two-parameter models, in contrast to another, more recent three-parameter empirical model introduced in 2010 (which failed for gradients starting at a non-zero concentration of acetonitrile). Both a longer (5cm) and more efficient Chromolith HR column and a shorter (2.5cm) slightly less efficient Chromolith Flash column provide useful separations in fast gradients (1-2min) at high flow rates (3.5-5mL/min), especially in second dimension of two-dimensional LC×LC, in combination with HILIC separation on monolithic microcolumn in D1.
