Weak coupling of neurons enables very high-frequency and ultra-fast oscillations through the interplay of synchronized phase-shifts

Recently, in the past decade, high-frequency oscillations (HFOs), very high-frequency oscillations (VHFOs), and ultra-fast oscillations (UFOs) were reported in epileptic patients with drug-resistant epilepsy. However, to this day, the physiological origin of these events has yet to be understood. Our study establishes a mathematical framework based on bifurcation theory for investigating the occurrence of VHFOs and UFOs in depth EEG signals of patients with focal epilepsy, focusing on the potential role of reduced connection strength between neurons in an epileptic focus. We demonstrate that synchronization of a weakly coupled network can generate very and ultra high-frequency signals detectable by nearby microelectrodes. In particular, we show that a bistability region enables the persistence of phase-shift synchronized clusters of neurons. This phenomenon is observed for different hippocampal neuron models, including Morris-Lecar, Destexhe-Paré, and an interneuron model. The mechanism seems to be robust for small coupling, and it also persists with random noise affecting the external current. Our findings suggest that weakened neuronal connections could contribute to the production of oscillations with frequencies above 1000Hz, which could advance our understanding of epilepsy pathology and potentially improve treatment strategies. However, further exploration of various coupling types and complex network models is needed

Personal care product use and lifestyle affect phthalate and DINCH metabolite levels in teenagers and young adults

Humans are widely exposed to phthalates and their novel substitutes, and considering the negative health effects associated with some phthalates, it is crucial to understand population levels and exposure determinants. This study is focused on 300 urine samples from teenagers (aged 12-17) and 300 from young adults (aged 18-37) living in Czechia collected in 2019 and 2020 to assess 17 plasticizer metabolites as biomarkers of exposure. We identified widespread phthalate exposure in the study population. The diethyl phthalate metabolite monoethyl phthalate (MEP) and three di (2-ethylhexyl) phthalate metabolites were detected in the urine of >99% of study participants. The highest median concentrations were found for metabolites of low-molecular-weight (LMW) phthalates: mono-n-butyl phthalate (MnBP), monoisobutyl phthalate (MiBP) and MEP (60.7; 52.6 and 17.6 μg/L in young adults). 1,2-cyclohexanedicarboxylic acid diisononyl ester (DINCH) metabolites were present in 68.2% of the samples with a median of 1.24 μg/L for both cohorts. Concentrations of MnBP and MiBP were similar to other European populations, but 5-6 times higher than in populations in North America. We also observed large variability in phthalate exposures within the study population, with 2-3 orders of magnitude differences in urinary metabolites between high and low exposed individuals. The concentrations varied with season, gender, age, and lifestyle factors. A relationship was found between high levels of MEP and high overall use of personal care products (PCPs). Cluster analysis suggested that phthalate exposures depend on season and multiple lifestyle factors, like time spent indoors and use of PCPs, which combine to lead to the observed widespread presence of phthalate metabolites in both study populations. Participants who spent more time indoors, particularly noticeably during colder months, had higher levels of high-molecular weight phthalate metabolites, whereas participants with higher PCP use, particularly women, tended to have higher concentration of LMW phthalate metabolites.Authors thank the Research Infrastructure RECETOX RI (No. LM2018121) and CETOCOEN EXCELLENCE (CZ.02.1.01/0.0/0.0/17_043/0009632) for a supportive background. The work was supported by the Operational Programme Research, Development and Innovation – project Cetocoen Plus (CZ.02.1.01/0.0/0.0/15_003/0000469) and the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 857560. This study has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 733032. We thank all collaborating field workers, laboratory and administrative personnel, and especially the cohort participants who invested their time and provided samples and information for this study. This study reflects only the authors’ view and the European Commission is not responsible for any use that may be made of the information it contains.S

Revisiting ab initio carcinoembryonic antigen and CA19-9 tumor markers in colorectal carcinoma in association with anatomotopographic location and staging of disease

OBJECTIVE: This study purposed to evaluate preoperative two tumor markers, namely, carcinoembryonic antigen and carbohydrate antigen (CA)19-9, in colorectal cancer for anatomotopographic location with disease stage and to assess their utility for diagnostic staging purposes. METHODS: The study retrospectively incorporated patients who had undergone surgery for colorectal cancer at our department in 2015-2018 and in whom carcinoembryonic antigen and CA19-9 tumor markers had been preoperatively analyzed. The obtained data were then statistically processed using R-project. RESULTS: A total of 155 patients had been incorporated, of whom 96 (62%) were men and 59 (38%) were women. Rectum was the most common location (74 patients, 48%), and the least represented stage was IV (18, 12%). The marker carcinoembryonic antigen was obtained in all 155 cases, while CA19-9 was in 105. The median carcinoembryonic antigen was 3 (0.34-1104.25), and the median CA19-9 was 12 (0.18-840.00). A significance was recognized between median carcinoembryonic antigen and disease stage (p-value=0.016), with stages I, II, and III (medians 2, 3, and 2) different from stage IV (median 13), while no significance for CA19-9 was recognized (p-value=0.343). No significance between either marker and location (carcinoembryonic antigen: p=0.276; CA19-9: p=0.505) was detected. The testing was performed at a significance level of alpha=0.05. CONCLUSION: This study revealed a significance between the marker carcinoembryonic antigen, but not CA19-9, and the disease stage, while no relationship of either of these markers with tumor location was found. Herewith, the study confirmed that higher carcinoembryonic antigen values may suggest the finding of more advanced forms of colorectal cancer and thus a worse prognosis of this malignant phenomenon

Evaluation of the financial situation and reporting system in company Dopravní podnik města Hradce Králové, a.s.

Práce se zabývá problematikou zhodnocení finanční situace a reportingového systému ve společnosti Dopravní podnik města Hradce Králové, a.s. První část práce pojednává o specifikách podniků zajišťujících městskou hromadnou dopravu v oblasti měření jejich hodnotových výsledků. Druhá část se věnuje manažerskému účetnictví, konkrétně oblasti reportingového systému. Práce nejprve hodnotí současný stav a poté navrhuje řadu zlepšení v oblasti zajištění relevantních informací potřebných pro kvalitní řízení společnosti.The thesis deals with evaluation of the financial situation and reporting system in the company Dopravní podnik města Hradce Králové, a.s.. The first part explains specifics of companies providing public transport in the area of measuring their financial results. The second part is focused on management accounting, especially the reporting system. Firstly presents current state of reporting system and then suggests a number of improvements to ensure relevant information needed for quality of managing company

Heuristics for capacitated messenger problem

This diploma thesis deals with static and dynamic capacitated messenger problem and its solving with heuristic algorithms. Different variations of the capacitated messenger problem were considered, with a single messenger or multiple messengers, with one depot or multiple depots in case of multiple messengers. Limited time for route realization was another modification that was considered. Modified nearest neighbour method, modified insertion method and modified exchange method were used to solve the problem. The main contribution of the thesis is deriving heuristics for described types of messenger problem and programming the algorithms in VBA (Visual Basic for Applications) in MS Excel. The results of computational experiments indicate that modified nearest neighbour method leads to better outcomes in static multiple messenger problems with a single depot, while modified insertion method is associated with lower values of objective function in static multiple messenger problem with multiple depots. Modified exchange method improves original solutions. Modified insertion method was approved for solving dynamic multiple messenger problems

The employment of juveniles and graduates

Import 10/09/2007Prezenční119 - Katedra práv

Solving the Battleship Solitaire puzzle as an integer programming problem

The bachelor thesis deals with the Battleship Solitaire puzzle. It introduces the history and the rules of this puzzle, which are thereafter used to formulate the puzzle as an integer programming problem. Two mathematical models based on different approaches are created, a cell-based model and a ship-based model. In order to determine whether a puzzle has a unique solution an objective function is added to each model. Both models are developed in LINGO modeling language and tested with different grid sizes. The test results show that even though the ship-based model uses fewer variables and constraints, it is too demanding in terms of data processing. It results in longer solving times and the model fails to find a solution for larger grids. Solving the problem using the cell-based model is significantly faster. The solution was found even for larger grids, though the solving time was very long

Stochastic modeling and optimization of risks

Dizertační práce na téma Stochastické modelování a optimalizace rizik se zabývá modelováním ve dvou aplikačních oblastech medicíny. A to v oblasti kolorektální chirurgie, kdy je předmětem zkoumání výskyt anastomotického leaku při operacích rekta. Druhou zkoumanou oblastí je problematika léčby kritické končetinové ischemie pomocí kmenových buněk. Práce ukazuje metody, kterými je možné matematicky popsat tyto lékařské problémy, srovnat účinnost použitých metod a predikovat úspěšnost léčby. Práce obsahuje jedenáct kapitol. Úvodní část vymezuje pojem stochastické modelování. V druhé kapitole jsou shrnuty cíle dizertační práce. V kapitole Úvod do lékařské problematiky je uveden stručný přehled modelovaných aplikačních oblastí. V následujících kapitolách je uveden přehled matematické teorie. Ve čtvrté kapitole je pasáž věnovaná klasické analýze přežití. Inovativní přístup neparametrické prediktivní inference je představen v páté kapitole. V šesté kapitole je uveden popis analýzy hlavních komponent, v~sedmé kapitole bootstrapové metody a v~osmé kapitole logistická regrese. V~deváté kapitole je uvedena samotná statistická analýza výskytu anastomotického leaku při operacích rekta, v~desáté kapitole modelování v~oblasti léčby kritické končetinové ischemie. V~závěru je uvedeno shrnutí s aplikačním medicínským dopadem. Následuje seznam použité literatury a přehled publikací autorky. V Příloze jsou uvedeny stručné přehledy některých R-skriptù sloužících k implementaci vytvořených stochastických modelù. Úplná verze R-skriptù je uvedena na přiloženém CD.Doctoral thesis called Stochastic modeling and optimization of risks deals with stochastic modeling in two application areas of medicine, namely in the field of colorectal surgery, where the occurrence of anastomotic leakage in rectal surgery is investigated. The second investigated area is the treatment of critical limb ischemia by stem cells. The thesis show methods by which it is possible to mathematically describe these medical problems, compare the effectiveness of the methods used and predict the success of treatment. The thesis contains eleven chapters. The introductory part defines the concept of stochastic modeling. The second chapter summarizes the objectives of the dissertation. In the chapter Introduction to Medical Issues there is a brief overview of two modeled application areas, colorectal surgery and treatment of critical limb ischemia using stem cells. The following chapters give an overview of mathematical theory. In the chapter 4 there is a passage devoted to the classical survival analysis. Chapter five give innovative approach in survival analysis called nonparametric predictive inference. Chapter six describes the principal component analysis, at chapter seven is description of bootstrap methods. Chapter eight contains logistical regression. In the chapters nine and ten is described modeling at applications areas. In the appendix is the overall conclusion with the application effect in medicine. Next follows list of used literature and an overview of the author's publications. The attachment provides brief summaries of some R-scripts used for implementation of the created stochastic models. The full version of the R-scripts is included on the attached CD.470 - Katedra aplikované matematikyvyhově

Financial analysis of firm Petrof, s.r.o.

Thesis on "Financial analysis of firm Petrof, s.r.o." is divided into two parts. The first part is concerned with methodical interpretation of financial analysis, in the second part is this described methodology applied on firm Petrof, s.r.o. In order to evaluate the company's financial situation observed in the period 2006-2008 external financial analysis is processed. This analysis utilizes the differential and ratio indicators and the bankruptcy model index IN05 and Du Pont analysis of return on equity index