Quantitative structure - activity relationships (QSARs) for the pIC50 (binding affinity) of gamma-secretase inhibitors can be constructed with the Monte Carlo method using CORAL software (http://www.insilico.eu/coral). The considerable influence of the presence of rings of various types with respect to the above endpoint has been detected. The mechanistic interpretation and the domain of applicability of the QSARs are discussed. Methods to select new potential gamma-secretase inhibitors are suggested.

• Klíčová slova
• CORAL software, Gamma-secretase inhibitor, Monte Carlo method, OECD principles, QSAR,
• MeSH
• Alzheimerova nemoc farmakoterapie   MeSH
• kvantitativní vztahy mezi strukturou a aktivitou MeSH
• lidé MeSH
• metoda Monte Carlo MeSH
• objevování léků metody   MeSH
• sekretasy * antagonisté a inhibitory   chemie   metabolismus   MeSH
• software MeSH
• výpočetní biologie metody   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• sekretasy * MeSH

• MeSH
• dítě MeSH
• hospitalizace MeSH
• lidé MeSH
• lůžková kapacita nemocnice * MeSH
• metoda Monte Carlo * MeSH
• mladiství MeSH
• operační výzkum * MeSH
• předškolní dítě MeSH
• strabismus terapie   MeSH
• věkové faktory MeSH
• výstavba, architektura a design nemocnic MeSH
• zdravotnická zařízení - velikost * MeSH
• Check Tag
• dítě MeSH
• lidé MeSH
• mladiství MeSH
• předškolní dítě MeSH
• Publikační typ
• anglický abstrakt MeSH
• časopisecké články MeSH
• Geografické názvy
• Československo MeSH

By optimization of so-called correlation weights of attributes of simplified molecular input-line entry system (SMILES) quantitative structure - activity relationships (QSAR) for toxicity towards Pimephales promelas are established. A new SMILES attribute has been utilized in this work. This attribute is a molecular descriptor, which reflects (i) presence of different kinds of bonds (double, triple, and stereo chemical bonds); (ii) presence of nitrogen, oxygen, sulphur, and phosphorus atoms; and (iii) presence of fluorine, chlorine, bromine, and iodine atoms. The statistical characteristics of the best model are the following: n=226, r2=0.7630, RMSE=0.654 (training set); n=114, r2=0.7024, RMSE=0.766 (calibration set); n=226, r2=0.6292, RMSE=0.870 (validation set). A new criterion to select a preferable split into the training and validation sets are suggested and discussed.

• Klíčová slova
• CORAL software, Monte carlo method, Pimephales promelas, QSAR, Toxicity,
• MeSH
• biologické modely * MeSH
• chemické látky znečišťující vodu chemie   toxicita   MeSH
• Cyprinidae růst a vývoj   metabolismus   MeSH
• kvantitativní vztahy mezi strukturou a aktivitou * MeSH
• LD50 MeSH
• metoda Monte Carlo * MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• chemické látky znečišťující vodu MeSH

• MeSH
• amblyopie terapie   MeSH
• dítě MeSH
• lidé MeSH
• metoda Monte Carlo * MeSH
• operační výzkum * MeSH
• počítače MeSH
• strabismus terapie   MeSH
• Check Tag
• dítě MeSH
• lidé MeSH
• Publikační typ
• anglický abstrakt MeSH
• časopisecké články MeSH

Calculation of radiation protection quantities in tissue equivalent material from measurements using semiconductor detectors requires correction factors for conversion of the measured values in the semiconductor material to the tissue equivalent material. This approach has been used many times in aircraft and for space dosimetry. In this paper, we present the results of Monte Carlo simulations which reveal the need to take into account both the radiation field and the detector material when performing the conversion of measured values to radiation protection quantities. It is shown that for low Z target material, most of the dose equivalent at aviation altitudes comes from neutrons originating from nuclear reactions, while in high Z targets most of the dose equivalent comes from photons, originating from electromagnetic reactions.

• Klíčová slova
• Monte Carlo simulations, Radiation dosimetry, Semiconductor detector,
• MeSH
• atmosféra MeSH
• dávka záření MeSH
• fotony MeSH
• metoda Monte Carlo MeSH
• neutrony * MeSH
• polovodiče MeSH
• radiometrie * metody   MeSH
• Publikační typ
• časopisecké články MeSH

Objective.In the present hadrontherapy scenario, there is a growing interest in exploring the capabilities of different ion species other than protons and carbons. The possibility of using different ions paves the way for new radiotherapy approaches, such as the multi-ions treatment, where radiation could vary according to target volume, shape, depth and histologic characteristics of the tumor. For these reasons, in this paper, the study and understanding of biological-relevant quantities was extended for the case of4He ion.Approach.Geant4 Monte Carlo based algorithms for dose- and track-averaged LET (Linear Energy Transfer) calculations, were validated for4He ions and for the case of a mixed field characterised by the presence of secondary ions from both target and projectile fragmentation. The simulated dose and track averaged LETs were compared with the corresponding dose and frequency mean values of the lineal energy,yD¯andy¯F, derived from experimental microdosimetric spectra. Two microdosimetric experimental campaigns were carried out at the Italian eye proton therapy facility of the Laboratori Nazionali del Sud of Istituto Nazionale di Fisica Nucleare (INFN-LNS, Catania, I) using two different microdosimeters: the MicroPlus probe and the nano-TEPC (Tissue Equivalent Proportional Counter).Main results.A good agreement ofL¯dTotalandL¯tTotalwithy¯Dandy¯Texperimentally measured with both microdosimetric detectors MicroPlus and nano-TEPC in two configurations: full energy and modulated4He ion beam, was found.Significance.The results of this study certify the use of a very effective tool for the precise calculation of LET, given by a Monte Carlo approach which has the advantage of allowing detailed simulation and tracking of nuclear interactions, even in complex clinical scenarios.

• Klíčová slova
• Geant4, Monte Carlo, linear energy transfer, microdosimetry, target fragmentation,
• MeSH
• algoritmy MeSH
• ionty MeSH
• lineární přenos energie * MeSH
• metoda Monte Carlo MeSH
• protony MeSH
• radiometrie * metody   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• ionty MeSH
• protony MeSH

In multiple-criteria decision making/aiding/analysis (MCDM/MCDA) weights of criteria constitute a crucial input for finding an optimal solution (alternative). A large number of methods were proposed for criteria weights derivation including direct ranking, point allocation, pairwise comparisons, entropy method, standard deviation method, and so on. However, the problem of correct criteria weights setting persists, especially when the number of criteria is relatively high. The aim of this paper is to approach the problem of determining criteria weights from a different perspective: we examine what weights' values have to be for a given alternative to be ranked the best. We consider a space of all feasible weights from which a large number of weights in the form of n-tuples is drawn randomly via Monte Carlo method. Then, we use predefined dominance relations for comparison and ranking of alternatives, which are based on the set of generated cases. Further on, we provide the estimates for a sample size so the results could be considered robust enough. At last, but not least, we introduce the concept of central weights and the measure of its robustness (stability) as well as the concept of alternatives' multi-dominance, and show their application to a real-world problem of the selection of the best wind turbine.

• MeSH
• entropie MeSH
• metoda Monte Carlo MeSH
• metody pro podporu rozhodování * MeSH
• rozhodování * MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

NASA has encouraged studies on 226Ra deposition in the human brain to investigate the effects of exposure to alpha particles with high linear energy transfer, which could mimic some of the exposure astronauts face during space travel. However, this approach was criticized, noting that radium is a bone-seeker and accumulates in the skull, which means that the radiation dose from alpha particles emitted by 226Ra would be heavily concentrated in areas close to cranial bones rather than uniformly distributed throughout the brain. In the high background radiation areas of Ramsar, Iran, extremely high levels of 226Ra in soil contribute to a large proportion of the inhabitants' radiation exposure. A prospective study on Ramsar residents with a calcium-rich diet was conducted to improve the dose uniformity due to 226Ra throughout the cerebral and cerebellar parenchyma. The study found that exposure of the human brain to alpha particles did not significantly affect working memory but was significantly associated with increased reaction times. This finding is crucial because astronauts on deep space missions may face similar cognitive impairments due to exposure to high charge and energy particles. The current study was aimed to evaluate the validity of the terrestrial model using the Geant4 Monte Carlo toolkit to simulate the interactions of alpha particles and representative cosmic ray particles, acknowledging that these radiation types are only a subset of the complete space radiation environment.

• Klíčová slova
• Alpha particles, Monte Carlo simulation, Radiation, Radium, Space exploration,
• MeSH
• DNA MeSH
• lidé MeSH
• lineární přenos energie MeSH
• metoda Monte Carlo MeSH
• mozek MeSH
• prospektivní studie MeSH
• radium * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• DNA MeSH
• radium * MeSH

PURPOSE: The Geant4 Monte Carlo simulation toolkit was used to reproduce radiobiological parameters measured by irradiating three different cancerous cell lines with monochromatic and clinical proton beams. METHODS: The experimental set-up adopted for irradiations was fully simulated with a dedicated open-source Geant4 application. Cells survival fractions was calculated coupling the Geant4 simulations with two analytical radiobiological models: one based on the LEM (Local Effect Model) approach and the other on a semi-empirical parameterisation. Results was evaluated and compared with experimental data. RESULTS AND CONCLUSIONS: The results demonstrated the Geant4 ability to reproduce radiobiological quantities for different cell lines.

• Klíčová slova
• Geant4, Monte Carlo, Proton, RBE, Radiobiological model, Radiotherapy, Survival fraction,
• MeSH
• celková dávka radioterapie MeSH
• lidé MeSH
• metoda Monte Carlo * MeSH
• nádorové buněčné linie MeSH
• protonová terapie * MeSH
• radiobiologie MeSH
• reprodukovatelnost výsledků MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

BACKGROUND: In-vivo monitoring methods of carbon ion radiotherapy (CIRT) includes explorations of nuclear reaction products generated by carbon-ion beams interacting with patient tissues. Our research group focuses on in-vivo monitoring of CIRT using silicon pixel detectors. Currently, we are conducting a prospective clinical trial as part of the In-Vivo Monitoring project (InViMo) at the Heidelberg Ion Beam Therapy Center (HIT) in Germany. We are using an innovative, in-house developed, non-contact fragment tracking system with seven mini-trackers based on the Timepix3 technology developed at CERN. PURPOSE: This article focuses on the implementation of the mini-tracker in Monte Carlo (MC) based on FLUKA simulations to monitor secondary charged nuclear fragments in CIRT. The main objective is to systematically evaluate the simulation accuracy for the InViMo project. METHODS: The implementation involved integrating the mini-tracker geometry and the scoring mechanism into the FLUKA MC simulation, utilizing the finely tuned HIT beam line. The systematic investigation included varying mini-tracker angles (from 15 ∘ $15^\circ$ to 45 ∘ $45^\circ$ in 5 ∘ $5^\circ$ steps) during the irradiation of a head-sized phantom with therapeutic carbon-ion pencil beams. To evaluate our implemented FLUKA framework, a comparison was made between the experimental data and data obtained from MC simulations. To ensure the fidelity of our comparison, experiments were performed at the HIT using the parameters and setup established in the simulations. RESULTS: Our research demonstrates high accuracy in reproducing characteristic behaviors and dependencies of the monitoring method in terms of fragment distributions in the mini-tracker, track angles, emission profiles, and fragment numbers. Discrepancies in the number of detected fragments between the experimental data and the data obtained from MC simulations are less than 4% for the angles of interest in the InViMo detection system. CONCLUSIONS: Our study confirms the potential of our simulation framework to investigate the performance of monitoring inter-fractional anatomical changes in patients undergoing CIRT using secondary nuclear charged fragments escaping from the irradiated patient.

• Klíčová slova
• Monte Carlo simulations, Timepix3, carbon‐ion radiotherapy, charged nuclear fragments, in‐vivo monitoring,
• MeSH
• fantomy radiodiagnostické MeSH
• lidé MeSH
• metoda Monte Carlo * MeSH
• radioterapie těžkými ionty * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• validační studie MeSH