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

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.

• Klíčová slova
• Dopamine, Dual-retention, Polymer monolith, Regression analysis, Retention model,
• MeSH
• betain analogy a deriváty   chemie   MeSH
• chemické modely * MeSH
• dopamin analogy a deriváty   chemie   MeSH
• molekulární struktura MeSH
• polymery chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• 3-methoxytyramine MeSH Prohlížeč
• betain MeSH
• dopamin MeSH
• polymery MeSH
• sulfobetaine MeSH Prohlížeč

Soils are recipients of microplastic that can be subsequently transferred to the sea. Land sources dominate inputs to the ocean, but knowledge gaps about microplastic retention by land hinder assessments of input rates. Here we present the first empirical evaluation of a dynamic microplastic fate model operating at landscape level. This mechanistic model accounts for hydrology, soil and sediment erosion, particle characteristics and behavior. We predict microplastic concentrations in water and sediments of the Henares river (Spain) within the measurement uncertainty boundaries (error factors below 2 and 10, respectively). Microplastic export from land and discharge by river fluctuates in a non-linear manner with precipitation and runoff variability. This indicates the need of accurate dynamic descriptions of soil and stream hydrology even when modeling microplastic fate and transport in generic scenarios and at low spatio-temporal resolution. A time-averaged landscape retention efficiency was calculated showing 20-50% of the microplastics added to the catchment over a multiannual period were retained. While the analysis reveals persistent uncertainties and knowledge gaps on microplastic sources to the catchment, these results contribute to the quantitative understanding of the role of terrestrial environments in accumulating microplastics, delaying their transport to the sea.

• Klíčová slova
• Fate and transport, Microplastics, Model, River, Soil,
• Publikační typ
• časopisecké články MeSH

The applicability and predictive properties of the linear solvent strength model and two nonlinear retention-time models, i.e., the quadratic model and the Neue model, were assessed for the separation of small molecules (phenol derivatives), peptides, and intact proteins. Retention-time measurements were conducted in isocratic mode and gradient mode applying different gradient times and elution-strength combinations. The quadratic model provided the most accurate retention-factor predictions for small molecules (average absolute prediction error of 1.5%) and peptides separations (with a prediction error of 2.3%). An advantage of the Neue model is that it can provide accurate predictions based on only three gradient scouting runs, making tedious isocratic retention-time measurements obsolete. For peptides, the use of gradient scouting runs in combination with the Neue model resulted in better prediction errors (<2.2%) compared to the use of isocratic runs. The applicability of the quadratic model is limited due to a complex combination of error and exponential functions. For protein separations, only a small elution window could be applied, which is due to the strong effect of the content of organic modifier on retention. Hence, the linear retention-time behavior of intact proteins is well described by the linear solvent strength model. Prediction errors using gradient scouting runs were significantly lower (2.2%) than when using isocratic scouting runs (3.2%).

• Klíčová slova
• Linear solvent strength model, Method development, Neue-Kuss model, Retention-time prediction, Selectivity,
• MeSH
• časové faktory MeSH
• chromatografie s reverzní fází * MeSH
• fenoly chemie   izolace a purifikace   MeSH
• molekulární modely MeSH
• molekulová hmotnost MeSH
• peptidy chemie   izolace a purifikace   MeSH
• proteiny chemie   izolace a purifikace   MeSH
• vysokoúčinná kapalinová chromatografie MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• fenoly MeSH
• peptidy MeSH
• proteiny MeSH

Retention prediction of monoamine neurotransmitters has been compared for the generally applied linear solvent-strength model and quadratic polynomial three-parameter model. The design of experiments protocol has been applied to plan linear gradients within the experimental space with altered gradient time, mobile phase flow rate, and column temperature. Relative prediction errors increased at elevated temperature, which is more significant for the linear solvent-strength model when compared to the polynomial model. On the other hand, the predefined design of experiments space controls the retention time errors, as predictions for LC conditions that are outside of the plan are much less accurate and should be avoided. The final part of the work deals with the effect of extracolumn band dispersion on the peak capacity of linear gradients at various gradient times, mobile phase flow rates, and column temperature. The peak capacity determined for corrected experimental data were consistent with the published results dealing with the optimization of peak capacity in gradient elution.

• Klíčová slova
• design of experiments, extracolumn volume, gradient elution, peak capacity, retention modeling,
• MeSH
• chromatografie kapalinová metody   MeSH
• indikátory a reagencie MeSH
• lineární modely MeSH
• neurotransmiterové látky * MeSH
• rozpouštědla chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• indikátory a reagencie MeSH
• neurotransmiterové látky * MeSH
• rozpouštědla MeSH

The CORAL software ( http://www.insilico.eu/coral ) was used to build up quantitative structure-property relationships (QSPRs) for the retention characteristics of 93 derivatives of three groups of heterocyclic compounds: 2-phenyl-1,3-benzoxazoles, 4-benzylsulfanylpyridines, and benzoxazines. The QSPRs are one-variable models based on the optimal descriptors calculated from the molecular structure represented by simplified molecular input-line entry systems (SMILES). Each symbol (or two undivided symbols) of SMILES is characterized by correlation weight. The optimal descriptor is the sum of the correlation weights. The numerical data on the correlation weights were calculated with the Monte Carlo method by the manner which provides best correlation between endpoint and optimal descriptor for the calibration set. The predictive ability of the model is checked with the validation set (compounds invisible during building up of the model). The approach has been checked with three random splits into the training, calibration, and validation sets: all models have apparent predictive potential. The mechanistic interpretation of the molecular features extracted from SMILES as the promoters of increase or decrease of examined endpoints is suggested.

• Klíčová slova
• CORAL software, Monte Carlo method, QSPR, Retention factor, SMILES,
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem 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.

• Klíčová slova
• Fluorescent derivatives, Hydrophilic interaction liquid chromatography, Liquid chromatography/mass spectrometry, Oligosaccharides, 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
• Názvy látek
• 1-naftylamin MeSH
• alpha-aminopyridine MeSH Prohlížeč
• aminopyridiny MeSH
• anthranilamide MeSH Prohlížeč
• anthranilic acid MeSH Prohlížeč
• maltooligosaccharides MeSH Prohlížeč
• oligosacharidy MeSH
• ortoaminobenzoáty MeSH
• oxid křemičitý MeSH

Retention index in gas chromatographic analyses is an essential tool for appropriate analyte identification. Currently, many libraries providing retention indices for a huge number of compounds on distinct stationary phase chemistries are available. However, situation could be complicated in the case of unknown unknowns not present in such libraries. The importance of identification of these compounds have risen together with a rapidly expanding interest in non-targeted analyses in the last decade. Therefore, precise in silico computation/prediction of retention indices based on a suggested molecular structure will be highly appreciated in such situations. On this basis, a predictive model based on deep learning was developed and presented in this paper. It is designed for user-friendly and accurate prediction of retention indices of compounds in gas chromatography with the semi-standard non-polar stationary phase. Simplified Molecular Input Entry System (SMILES) is used as the model's input. Architecture of the model consists of 2D-convolutional layers, together with batch normalization, max pooling, dropout, and three residual connections. The model reaches median absolute error of prediction of the retention index for validation and test set at 16.4 and 16.0 units, respectively. Median percentage error is lower than or equal to 0.81% in the case of all mentioned data sets. Finally, the DeepReI model is presented in R package, and is available on https://github.com/TomasVrzal/DeepReI together with a user-friendly graphical user interface.

• Klíčová slova
• Artificial intelligence, Convolutional network, Deep learning, Gas chromatography, Retention index,
• Publikační typ
• časopisecké články MeSH

In this work, we have investigated the predictive properties of mixed-mode retention model and oligomeric mixed-mode model, taking into account the contribution of monomeric units to the retention, in hydrophilic interaction liquid chromatography. The gradient retention times of native maltooligosaccharides and their fluorescent derivatives were predicted in the oligomeric series with number of monomeric glucose units in the range from two to seven. The maltooligosaccharides were separated on a packed column with carbamoyl-bonded silica stationary phase and 15 gradient profiles with different initial and final mobile phase composition were used with the gradient times 5; 7.5 and 10min. The predicted gradient retention times were compared for calculations based on isocratic retention data and gradient retention data, which provided better accuracy of the results. By comparing two different mobile phase additives, the more accurate retention times were predicted in mobile phases containing ammonium acetate. The acidic derivatives, prepared by reaction of an oligosaccharide with 2-aminobenzoic acid or 8-aminonaphthalene-1,3,6-trisulfonic acid, provided more accurate predictions of the retention data in comparison to native oligosaccharides or their neutral derivatives. The oligomeric mixed-mode model allowed prediction of gradient retention times using only one gradient profile, which significantly speeded-up the method development.

• Klíčová slova
• Gradient elution, Hydrophilic interaction liquid chromatography, Mixed-mode retention model, Oligomers, Prediction,
• MeSH
• chromatografie kapalinová metody   MeSH
• fluorescenční barviva chemie   MeSH
• hydrofobní a hydrofilní interakce MeSH
• naftaleny chemie   MeSH
• oligosacharidy chemie   izolace a purifikace   MeSH
• ortoaminobenzoáty chemie   MeSH
• oxid křemičitý MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• 8-amino-1,3,6-naphthalenetrisulfonic acid MeSH Prohlížeč
• anthranilic acid MeSH Prohlížeč
• fluorescenční barviva MeSH
• maltooligosaccharides MeSH Prohlížeč
• naftaleny MeSH
• oligosacharidy MeSH
• ortoaminobenzoáty MeSH
• oxid křemičitý MeSH

In this paper, the concentration of N-isopropylacrylamide in the polymerization mixture has been varied to prepare several polymethacrylate monolithic capillary columns. Polymer monoliths combining N-isopropylacrylamide with zwitterion monomer, as well as various dimethacrylate crosslinking monomers have been prepared and characterized. Uracil, thiourea, phenol, toluene, ethylbenzene, propylbenzene, and butylbenzene have been used to characterize retention of prepared capillary columns in the mobile phases with 40-95% of acetonitrile and at working temperatures ranging from 25 to 60°C. By an optimization of six-parameter polynomial models we have found that the retention of small molecules is affected mainly by the concentration of the acetonitrile in the mobile phase with very low contribution of working temperature and combined effect of acetonitrile concentration and temperature. Concentration of the mobile phase controlled also enthalpy of the retention. On the other hand, entropic contribution was almost insensitive to the change of the mobile phase composition, especially for mobile phases containing more than 60% of acetonitrile.

• Klíčová slova
• N-isopropylacrylamide, Polymer monoliths, Retention, Small molecules, Temperature,
• MeSH
• akrylamidy chemie   MeSH
• chromatografie metody   MeSH
• entropie MeSH
• hydrodynamika MeSH
• kyseliny polymethakrylové chemie   MeSH
• polymerizace MeSH
• regresní analýza MeSH
• reprodukovatelnost výsledků MeSH
• teplota MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• akrylamidy MeSH
• kyseliny polymethakrylové MeSH
• N-isopropylacrylamide MeSH Prohlížeč
• polymethacrylic acid MeSH Prohlížeč