PURPOSE: A supervised deep learning (DL) approach for frequency and phase correction (FPC) of MRS data recently showed encouraging results, but obtaining transients with labels for supervised learning is challenging. This work investigates the feasibility and efficiency of unsupervised deep learning-based FPC. METHODS: Two novel deep learning-based FPC methods (deep learning-based Cr referencing and deep learning-based spectral registration), which use a priori physics domain knowledge, are presented. The proposed networks were trained, validated, and evaluated using simulated, phantom, and publicly accessible in vivo MEGA-edited MRS data. The performance of our proposed FPC methods was compared with other generally used FPC methods, in terms of precision and time efficiency. A new measure was proposed in this study to evaluate the FPC method performance. The ability of each of our methods to carry out FPC at varying SNR levels was evaluated. A Monte Carlo study was carried out to investigate the performance of our proposed methods. RESULTS: The validation using low-SNR manipulated simulated data demonstrated that the proposed methods could perform FPC comparably with other methods. The evaluation showed that the deep learning-based spectral registration over a limited frequency range method achieved the highest performance in phantom data. The applicability of the proposed method for FPC of GABA-edited in vivo MRS data was demonstrated. Our proposed networks have the potential to reduce computation time significantly. CONCLUSIONS: The proposed physics-informed deep neural networks trained in an unsupervised manner with complex data can offer efficient FPC of large MRS data in a shorter time.

• Klíčová slova
• MR spectroscopy, deep learning, edited MRS, frequency correction, phase correction,
• MeSH
• deep learning * MeSH
• fantomy radiodiagnostické MeSH
• metoda Monte Carlo MeSH
• neuronové sítě (počítačové) MeSH
• počítačové zpracování obrazu metody   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Correct adjustment of the mobile phase is equally important as the selection of the appropriate column for the separation of polar compounds in LC. Both solvophobic and selective polar interactions control the retention in the Reversed Phase and Hydrophilic Interaction modes. The retention models describing the effects of the volume fraction of the strong eluent component in binary mobile phases on the sample retention factors apply in a limited mobile phase composition range. We introduced a three-parameter retention model, which provides improved prediction of retention over a broad mobile phase range, under isocratic and gradient elution conditions. The model does not imply any assumptions concerning either adsorption or partition distribution mechanism, but allows estimating retention in pure strong and in pure weak mobile phase components. The experimental retention data for phenolic acids and flavones on several core-shell columns with different types of stationary phases agree with the theory. Many polar columns with important structural hydrophobic moieties show dual retention mechanism, (Reversed Phase in water rich mobile phases and Hydrophilic Interaction at high acetonitrile concentrations). It is possible to select the mobile phase compositions in each of the two modes for separations of samples containing compounds largely differing in polarity. The three-parameter model describes the retention in each mode, with separately determined best-fit parameters. We applied the two-mode model to the retention data of sulfonamides and benzoic acid related compounds on a new polymethacrylate zwitterionic monolithic micro-column.

• Klíčová slova
• Dual retention mechanism, Gradient elution, Monolithic zwitterionic polymethacrylate column, Prediction of retention, Retention models,
• MeSH
• adsorpce MeSH
• chemické modely MeSH
• chromatografie kapalinová * MeSH
• chromatografie s reverzní fází * MeSH
• flavony chemie   MeSH
• hydrofobní a hydrofilní interakce MeSH
• hydroxybenzoáty chemie   MeSH
• voda chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• flavony MeSH
• hydroxybenzoáty MeSH
• phenolic acid MeSH Prohlížeč
• voda MeSH

Artifact-free microscopic images represent a key requirement of multi-parametric image analysis in modern biomedical research. Holography microscopy (HM) is one of the quantitative phase imaging techniques, which has been finding new applications in life science, especially in morphological screening, cell migration, and cancer research. Rather than the classical imaging of absorbing (typically stained) specimens by bright-field microscopy, the information about the light-wave's phase shifts induced by the biological sample is employed for final image reconstruction. In this comparative study, we investigated the usability and the reported advantage of the holography imaging. The claimed halo-free imaging was analyzed compared to the widely used Zernike phase-contrast microscopy. The intensity and phase cross-membrane profiles at the periphery of the cell were quantified. The intensity profile for cells in the phase-contrast images suffers from the significant increase in intensity values around the cell border. On the contrary, no distorted profile is present outside the cell membrane in holography images. The gradual increase in phase shift values is present in the internal part of the cell body projection in holography image. This increase may be related to the increase in the cell internal material according to the dry mass theory. Our experimental data proved the halo-free nature of the holography imaging, which is an important prerequisite of the correct thresholding and cell segmentation, nowadays frequently required in high-content screening and other image-based analysis. Consequently, HM is a method of choice whenever the image analysis relies on the accurate data on cell boundaries.

• Klíčová slova
• Halo effect, Holography microscopy, Phase-contrast,
• MeSH
• artefakty MeSH
• HeLa buňky MeSH
• holografie * MeSH
• lidé MeSH
• mikroskopie fázově kontrastní * MeSH
• nádorové buňky kultivované MeSH
• Saccharomyces cerevisiae cytologie   růst a vývoj   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

PURPOSE OF THE STUDY Partial knee replacement appears to be an appropriate surgical solution of unicompartmental knee joint osteoarthritis in correctly indicated cases. The purpose of our study was to evaluate the mid-term outcomes of unicondylar knee replacement using the Oxford Phase III system in the group of patients treated by the First Department of Orthopaedic Surgery, St. Anne s University Hospital Brno. MATERIAL AND METHODS The prospective study evaluated 47 patients (in 4 patients bilaterally) after the Oxford unicompartmental knee replacement performed between 2011 and 2016. The patients were evaluated using the Knee Society Score (KSS), Oxford Knee Score (OKS) and radiological examination performed at 7.3 years after surgery on average. All the patients were operated on by the same surgeon. RESULTS Based on the questionnaires and the clinical examination, the clinical and functional status was assessed, using the Knee Society Score (KSS). The mean preoperative KSS and FS values were 59.8 and 56.5, respectively. The postoperative KSS and FS values were 91.2 and 83.4. The mean preoperative value of the Oxford Knee Score (OKS) was 27.3. Postoperatively the values reached 40.7 on average. Based on the radiological examination, the lower limb correction of axis in the frontal plane was assessed. The mean axis correction was 3.1°. The mean tibial component slope measured on lateral radiograph was 82.7°. The basic analysis of X-rays did not reveal any component malposition. The implant survival rate was calculated using the Kaplan-Meier cumulative survival curve. In our group of patients, the mean survival rate of Oxford Phase III unicondylar knee replacement at 7.3 years postoperatively is 98.0%. DISCUSSION Many studies have reported excellent results of unicondylar knee replacement and a long survival rate of over 90%. Still debated, however, are the indication criteria and also the importance of the surgeon s experience and mastery of the surgical technique. CONCLUSIONS The results of the study confirm our excellent clinical experience and the survival rate of 98% at the mean follow up of 7.3 years after surgery shows great promise for quality long-term results. Overall, crucial for the success of UKR continues to be the compliance with the indication criteria for surgery. The choice of the type of implant and, last but not least, the correct surgical technique and postoperative rehabilitation programme are also important. Key words: unicompartmental knee replacement, Oxford Phase III, osteoarthritis of the knee.

• MeSH
• artróza kolenních kloubů * chirurgie   MeSH
• lidé MeSH
• prospektivní studie MeSH
• totální endoprotéza kolene * MeSH
• výsledek terapie MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• anglický abstrakt MeSH
• časopisecké články MeSH

The composition of plant membrane lipids was investigated by reversed-phase high performance liquid chromatography mass spectrometry with accurate mass measurement. The data dependent methods for the analysis of monogalactosyldiacylglycerols (MGDGs) and digalactosyldiacylglycerols (DGDGs) have been developed. The optimised chromatographic systems were based on a 2.0 mm i.d. Nucleosil C18 column with methanol/water (MGDGs) or acetonitrile/methanol/water (DGDGs) gradients. The galactolipids were ionised by electrospray operated in the positive ion mode and identified based on their MS/MS spectra. High resolution spectra with accurate masses were found to be essential for correct interpretation of the MS data. The elution order of non-oxidised MGDGs and DGDGs followed the equivalent carbon numbers. The methods were applied for detailed characterisation of the MGDGs and DGDGs in the leaves of Arabidopsis thaliana and Melissa officinalis.

• MeSH
• Arabidopsis chemie   MeSH
• chromatografie s reverzní fází MeSH
• galaktolipidy chemie   MeSH
• hmotnostní spektrometrie s elektrosprejovou ionizací MeSH
• meduňka chemie   MeSH
• oxidace-redukce MeSH
• vysokoúčinná kapalinová chromatografie MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• galaktolipidy MeSH
• monogalactosyldiacylglycerol MeSH Prohlížeč

• Publikační typ
• tisková chyba MeSH

Experimental analyses of depth distributions of phase-specific residual stresses after deep rolling were carried out by means of laboratory X-ray diffraction and neutron diffraction for the two duplex steels X2CrNiMoN22-5-3 and X3CrNiMoN27-5-2, which differ significantly in their ferrite to austenite ratios. The aim of the investigation was to elucidate to which extent comparable results can be achieved with the destructive and the non-destructive approach and how the process induced phase-specific micro residual stresses influence the determination of the phase- and {hkl}-specific reference value d0, required for evaluation of neutron strain scanning experiments. A further focus of the work was the applicability of correction approaches that were developed originally for single-phase materials for accounting for spurious strains during through surface neutron scanning experiments on coarse two-phase materials. The depth distributions of macro residual stresses were separated from the phase-specific micro residual stresses. In this regard, complementary residual stress analysis was carried out by means of incremental hole drilling. The results indicate that meaningful macro residual stress depth distributions can be determined non-destructively by means of neutron diffraction for depths starting at about 150-200 µm. Furthermore, it was shown that the correction of the instrumental surface effects, which are intrinsic for surface neutron strain scanning, through neutron ray-tracing simulation is applicable to multiphase materials and yields reliable results. However, phase-specific micro residual stresses determined by means of neutron diffraction show significant deviations to data determined by means of lab X-ray stress analysis according to the well-known sin2ψ-method.

• Klíčová slova
• duplex steel, incremental hole drilling, macro stress, neutron diffraction, phase specific stress, phase specific texture, phase-specific micro residual stresses, residual stress measurement, soft X-ray sin2ψ, surface effect,
• Publikační typ
• časopisecké články MeSH

Accurate copying of DNA during S phase is essential for genome stability and cell viability. During genome duplication, the progression of the DNA replication machinery is challenged by limitations in nucleotide supply and physical barriers in the DNA template that include naturally occurring DNA lesions and secondary structures that are difficult to replicate. To ensure correct and complete replication of the genome, cells have evolved several mechanisms that protect DNA replication forks and thus maintain genome integrity and stability during S phase. One class of enzymes that have recently emerged as important in this process, and therefore as promising targets in anticancer therapy, are the poly(ADP-ribose) polymerases (PARPs). We review here the roles of these enzymes during DNA replication as well as their impact on genome stability and cellular viability in normal and cancer cells.

• Klíčová slova
• DNA replication stress, DNA strand break repair, Okazaki fragment, PARP1, PARP2, poly(ADP-ribose),
• MeSH
• aktivace enzymů MeSH
• antitumorózní látky farmakologie   terapeutické užití   MeSH
• cílená molekulární terapie MeSH
• lidé MeSH
• multigenová rodina MeSH
• náchylnost k nemoci MeSH
• nestabilita genomu MeSH
• oprava DNA MeSH
• PARP inhibitory farmakologie   terapeutické užití   MeSH
• poly(ADP-ribosa)-polymerasy genetika   metabolismus   MeSH
• poškození DNA MeSH
• proliferace buněk MeSH
• replikace DNA MeSH
• S fáze fyziologie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• antitumorózní látky MeSH
• PARP inhibitory MeSH
• poly(ADP-ribosa)-polymerasy MeSH

UV-benzotriazoles have been identified as water micropollutants that cause serious problems for human health and the environment. Their low concentration in water bodies complicates their detection by direct water analysis, slowing the corrective actions to avoid bioaccumulation. In this regard, the use of graphene-based materials with a high affinity for non-polar molecules has been demonstrated to be a potential tool for the optimal separation and concentration of this type of molecules in solid phase extraction (SPE) processes. This work evaluates the potential of novel reduced graphene oxide aerogels (rGO) as extractants of mixtures of three UV-benzotriazoles in water at low concentrations. These rGO aerogels incorporate graphenic domains into a tough structure of polymeric chains by adding graphene oxide during the synthesis of resorcinol-formaldehyde gels. Aerogels with a different content and ordering of graphenic domains were obtained and characterized using Raman, XRD, SEM and nitrogen adsorption isotherms (-196 °C). The rGO aerogels that performed better as solid phase extractants were those containing 60% rGO. Aerogels with lower rGO contents (40%) required a high-temperature (2000 °C) treatment to render competitive results. The SPE methodology using selected rGO aerogels was optimized by varying the elution solvent, elution time and volume. The best performances, i.e., recoveries of 80-100% and enrichment factors of 12.5-50, were accomplished when using 0.8 mL of tetrahydrofuran (THF) as an elution solvent. As a result, a fast (10 min) and simple extraction method of UV-benzotriazoles in water was attained, achieving a detection limit of 1 ng mL-1. Selected aerogels were finally tested for the SPE of spiked samples of river waters, showing a similar performance to that observed with synthetic mixtures.

• Klíčová slova
• SPE, UV-benzotriazoles, reduced graphene oxide aerogels, solid phase extraction,
• Publikační typ
• časopisecké články MeSH

Polar columns used in the HILIC (Hydrophilic Interaction Liquid Chromatography) systems take up water from the mixed aqueous-organic mobile phases in excess of the water concentration in the bulk mobile phase. The adsorbed water forms a diffuse layer, which becomes a part of the HILIC stationary phase and plays dominant role in the retention of polar compounds. It is difficult to fix the exact boundary between the diffuse stationary and the bulk mobile phase, hence determining the column hold-up volume is subject to errors. Adopting a convention that presumes that the volume of the adsorbed water can be understood as the column stationary phase volume enables unambiguous determination of the volumes of the stationary and of the mobile phases in the column, which is necessary for obtaining thermodynamically correct chromatographic data in HILIC systems. The volume of the aqueous stationary phase, Vex, can be determined experimentally by frontal analysis combined with Karl Fischer titration method, yielding isotherms of water adsorbed on polar columns, which allow direct prediction of the effects of the composition of aqueous-organic mobile phase on the retention in HILIC systems, and more accurate determination of phase volumes in columns and consistent retention data for any mobile phase composition. The n phase volume ratios of 18 columns calculated according to the new phase convention strongly depend on the type of the polar column. Zwitterionic and TSK gel amide and amine columns show especially strong water adsorption.

• Klíčová slova
• hydrophilic interaction, liquid chromatography, polar columns, stationary and mobile phase,
• Publikační typ
• časopisecké články MeSH