BACKGROUND: In severe conditions of limited motor abilities, frequent position changes for work or passive and active rest are essential bedside activities to prevent further health complications. We aimed to develop a system using eye movements for bed positioning and to verify its functionality in a control group and a group of patients with significant motor limitation caused by multiple sclerosis. METHODS: The eye-tracking system utilized an innovative digital-to-analog converter module to control the positioning bed via a novel graphical user interface. We verified the ergonomics and usability of the system by performing a fixed sequence of positioning tasks, in which the leg and head support was repeatedly raised and then lowered. Fifteen women and eleven men aged 42.7 ± 15.9 years in the control group and nine women and eight men aged 60.3 ± 9.14 years in the patient group participated in the experiment. The degree of disability, according to the Expanded Disability Status Scale (EDSS), ranged from 7 to 9.5 points in the patients. We assessed the speed and efficiency of the bed control and the improvement during testing. In a questionnaire, we evaluated satisfaction with the system. RESULTS: The control group mastered the task in 40.2 s (median) with an interquartile interval from 34.5 to 45.5 s, and patients mastered the task in in 56.5 (median) with an interquartile interval from 46.5 to 64.9 s. The efficiency of solving the task (100% corresponds to an optimal performance) was 86.3 (81.6; 91.0) % for the control group and 72.1 (63.0; 75.2) % for the patient group. Throughout testing, the patients learned to communicate with the system, and their efficiency and task time improved. A correlation analysis showed a negative relationship (rho = - 0.587) between efficiency improvement and the degree of impairment (EDSS). In the control group, the learning was not significant. On the questionnaire survey, sixteen patients reported gaining confidence in bed control. Seven patients preferred the offered form of bed control, and in six cases, they would choose another form of interface. CONCLUSIONS: The proposed system and communication through eye movements are reliable for positioning the bed in people affected by advanced multiple sclerosis. Seven of 17 patients indicated that they would choose this system for bed control and wished to extend it for another application.

• MeSH
• lidé MeSH
• pohyby očí MeSH
• postižení * MeSH
• průzkumy a dotazníky MeSH
• roztroušená skleróza * MeSH
• technologie sledování pohybu očí MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

Seventeen individuals of ide Leuciscus idus were radio-tracked weekly from September 2003 to September 2004 in the River Elbe, Czech Republic, to examine migration patterns and the influence of environmental factors on their diurnal behaviour. Of the 10 environmental factors measured, L. idus were significantly influenced by turbidity, which increased diurnal movement and the home range size of the species. The peak of longitudinal movement occurred in the spring, indicating pre-spawning migration. Migrating fish moved downstream and later returned upstream to the vicinity of their original locations, displaying a homing behaviour.

• MeSH
• Cyprinidae fyziologie   MeSH
• lineární modely MeSH
• migrace zvířat MeSH
• nefelometrie a turbidimetrie MeSH
• řeky MeSH
• teritoriální chování MeSH
• životní prostředí MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Česká republika MeSH

Much research on large herbivore movement has focused on the annual scale to distinguish between resident and migratory tactics, commonly assuming that individuals are sedentary at the within-season scale. However, apparently sedentary animals may occupy a number of sub-seasonal functional home ranges (sfHR), particularly when the environment is spatially heterogeneous and/or temporally unpredictable. The roe deer (Capreolus capreolus) experiences sharply contrasting environmental conditions due to its widespread distribution, but appears markedly sedentary over much of its range. Using GPS monitoring from 15 populations across Europe, we evaluated the propensity of this large herbivore to be truly sedentary at the seasonal scale in relation to variation in environmental conditions. We studied movement using net square displacement to identify the possible use of sfHR. We expected that roe deer should be less sedentary within seasons in heterogeneous and unpredictable environments, while migratory individuals should be seasonally more sedentary than residents. Our analyses revealed that, across the 15 populations, all individuals adopted a multi-range tactic, occupying between two and nine sfHR during a given season. In addition, we showed that (i) the number of sfHR was only marginally influenced by variation in resource distribution, but decreased with increasing sfHR size; and (ii) the distance between sfHR increased with increasing heterogeneity and predictability in resource distribution, as well as with increasing sfHR size. We suggest that the multi-range tactic is likely widespread among large herbivores, allowing animals to track spatio-temporal variation in resource distribution and, thereby, to cope with changes in their local environment.

• MeSH
• býložravci * MeSH
• roční období MeSH
• teritoriální chování MeSH
• vysoká zvěř * MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Evropa MeSH

The purpose of this study is to evaluate the dosimetric impact of the margin on the multileaf collimator-based dynamic tumor tracking plan. Furthermore, an equivalent setup margin (EM) of the tracking plan was determined according to the gated plan. A 4-dimensional extended cardiac-torso was used to create 9 digital phantom datasets of different tumor diameters (TDs) of 1, 3, and 5 cm and motion ranges (MRs) of 1, 2, and 3 cm. For each dataset, respiratory gating (30% to 70% phase) and tumor tracking treatment plans were prepared using 8-field 3-dimensional conformal radiation therapy by 4-dimensional dose calculation. The total lung V20 was calculated to evaluate the dosimetric impact for each case and to estimate the EM with the same impact on lung V20 obtained with the gating plan with a setup margin of 5 mm. The EMs for {TD = 1 cm, MR = 1 cm}, {TD = 1 cm, MR = 2 cm}, and {TD = 1 cm, MR = 3 cm} were estimated as 5.00, 4.16, and 4.24 mm, respectively. The EMs for {TD = 5 cm, MR = 1 cm}, {TD = 5 cm, MR = 2 cm}, and {TD = 5 cm, MR = 3 cm} were estimated as 4.24 mm, 6.35 mm, and 7.49 mm, respectively. This result showed that with a larger MR, the EM was found to be increased. In addition, with a larger TD, the EM became smaller. Our result showing the EMs provided the desired accuracy for multileaf collimator-based dynamic tumor tracking radiotherapy.

• MeSH
• celková dávka radioterapie * MeSH
• fantomy radiodiagnostické MeSH
• konformní radioterapie metody   MeSH
• lidé MeSH
• nádory plic patologie   radioterapie   MeSH
• plánování radioterapie pomocí počítače MeSH
• pohyb těles MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

Noninvasive cellular imaging allows the real-time tracking of grafted cells as well as the monitoring of their migration. Several techniques for in vivo cellular imaging are available that permit the characterization of transplanted cells in a living organism, including magnetic resonance imaging (MRI), bioluminescence, positron emission tomography, and multiple photon microscopy. All of these methods, based on different principles, provide distinctive, usually complementary information. In this review, we will focus on cell tracking using MRI, since MRI is noninvasive, clinically transferable, and displays good resolution, ranging from 50microm in animal experiments up to 300microm using whole body clinical scanners. In addition to information about grafted cells, MRI provides information about the surrounding tissue (i.e., lesion size, edema, inflammation), which may negatively affect graft survival or the functional recovery of the tissue. Transplanted cells are labeled with MR contrast agents in vitro prior to transplantation in order to visualize them in the host tissue. The chapter will focus on the use of superparamagnetic iron oxide nanoparticles (SPIO), because they have strong effects on T2 relaxation yet do not affect cell viability, and will provide an overview of different modifications of SPIO and their use in MR tracking in living organisms.

• MeSH
• buněčné kultury MeSH
• financování organizované MeSH
• kontrastní látky chemie   metabolismus   MeSH
• kovové nanočástice chemie   MeSH
• krysa rodu rattus MeSH
• kultivované buňky MeSH
• lidé MeSH
• magnetická rezonanční tomografie metody   přístrojové vybavení   MeSH
• mezenchymální kmenové buňky cytologie   fyziologie   MeSH
• mícha anatomie a histologie   metabolismus   patologie   MeSH
• mozek anatomie a histologie   metabolismus   patologie   MeSH
• neurodegenerativní nemoci metabolismus   patologie   MeSH
• transplantace mezenchymálních kmenových buněk MeSH
• železité sloučeniny chemie   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• lidé MeSH
• zvířata MeSH

Objective.Electrical deep brain stimulation (DBS) is an established treatment for patients with drug-resistant epilepsy. Sleep disorders are common in people with epilepsy, and DBS may actually further disturb normal sleep patterns and sleep quality. Novel implantable devices capable of DBS and streaming of continuous intracranial electroencephalography (iEEG) signals enable detailed assessments of therapy efficacy and tracking of sleep related comorbidities. Here, we investigate the feasibility of automated sleep classification using continuous iEEG data recorded from Papez's circuit in four patients with drug resistant mesial temporal lobe epilepsy using an investigational implantable sensing and stimulation device with electrodes implanted in bilateral hippocampus (HPC) and anterior nucleus of thalamus (ANT).Approach.The iEEG recorded from HPC is used to classify sleep during concurrent DBS targeting ANT. Simultaneous polysomnography (PSG) and sensing from HPC were used to train, validate and test an automated classifier for a range of ANT DBS frequencies: no stimulation, 2 Hz, 7 Hz, and high frequency (>100 Hz).Main results.We show that it is possible to build a patient specific automated sleep staging classifier using power in band features extracted from one HPC iEEG sensing channel. The patient specific classifiers performed well under all thalamic DBS frequencies with an average F1-score 0.894, and provided viable classification into awake and major sleep categories, rapid eye movement (REM) and non-REM. We retrospectively analyzed classification performance with gold-standard PSG annotations, and then prospectively deployed the classifier on chronic continuous iEEG data spanning multiple months to characterize sleep patterns in ambulatory patients living in their home environment.Significance.The ability to continuously track behavioral state and fully characterize sleep should prove useful for optimizing DBS for epilepsy and associated sleep, cognitive and mood comorbidities.

• MeSH
• epilepsie komplikace   MeSH
• hipokampus MeSH
• hluboká mozková stimulace * metody   MeSH
• lidé MeSH
• mozek MeSH
• nuclei anteriores thalami * MeSH
• poruchy spánku a bdění * komplikace   diagnóza   terapie   MeSH
• retrospektivní studie MeSH
• thalamus MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH

Stray radiation produced by ultra-high dose-rates (UHDR) proton pencil beams is characterized using ASIC-chip semiconductor pixel detectors. A proton pencil beam with an energy of 220 MeV was utilized to deliver dose rates (DR) ranging from conventional radiotherapy DRs up to 270 Gy/s. A MiniPIX Timepix3 detector equipped with a silicon sensor and integrated readout electronics was used. The chip-sensor assembly and chipboard on water-equivalent backing were detached and immersed in the water-phantom. The deposited energy, particle flux, DR, and the linear energy transfer (LET(Si)) spectra were measured in the silicon sensor at different positions both laterally, at different depths, and behind the Bragg peak. At low-intensity beams, the detector is operated in the event-by-event data-driven mode for high-resolution spectral tracking of individual particles. This technique provides precise energy loss response and LET(Si) spectra with radiation field composition resolving power. At higher beam intensities a rescaling of LET(Si) can be performed as the distribution of the LET(Si) spectra exhibits the same characteristics regardless of the delivered DR. The integrated deposited energy and the absorbed dose can be thus measured in a wide range. A linear response of measured absorbed dose was obtained by gradually increasing the delivered DR to reach UHDR beams. Particle tracking of scattered radiation in data-driven mode could be performed at DRs up to 0.27 Gy/s. In integrated mode, the saturation limits were not reached at the measured out-of-field locations up to the delivered DR of over 270 Gy/s. A good agreement was found between measured and simulated absorbed doses.

• MeSH
• křemík MeSH
• lineární přenos energie MeSH
• protonová terapie * metody   MeSH
• protony MeSH
• radiometrie * metody   MeSH
• voda MeSH
• Publikační typ
• časopisecké články MeSH

BACKGROUND: Cardiovascular magnetic resonance (CMR) 2D feature tracking (FT) left ventricular (LV) myocardial strain has seen widespread use to characterize myocardial deformation. Yet, validation of CMR FT measurements remains scarce, particularly for regional strain. Therefore, we aimed to perform intervendor comparison of 3 different FT software against tagging. METHODS: In 61 subjects (18 healthy subjects, 18 patients with chronic myocardial infarction, 15 with dilated cardiomyopathy, and 10 with LV hypertrophy due to hypertrophic cardiomyopathy or aortic stenosis) were prospectively compared global (G) and regional transmural peak-systolic Lagrangian longitudinal (LS), circumferential (CS) and radial strains (RS) by 3 FT software (cvi42, Segment, and Tomtec) among each other and with tagging at 3T. We also evaluated the ability of regional LS, CS, and RS by different FT software vs tagging to identify late gadolinium enhancement (LGE) in the 18 infarct patients. RESULTS: GLS and GCS by all 3 software had an excellent agreement among each other (ICC = 0.94-0.98 for GLS and ICC = 0.96-0.98 for GCS respectively) and against tagging (ICC = 0.92-0.94 for GLS and ICC = 0.88-0.91 for GCS respectively), while GRS showed inconsistent agreement between vendors (ICC 0.10-0.81). For regional LS, the agreement was good (ICC = 0.68) between 2 vendors but less vs the 3rd (ICC 0.50-0.59) and moderate to poor (ICC 0.44-0.47) between all three FT software and tagging. Also, for regional CS agreement between 2 software was higher (ICC = 0.80) than against the 3rd (ICC = 0.58-0.60), and both better agreed with tagging (ICC = 0.70-0.72) than the 3rd (ICC = 0.57). Regional RS had more variation in the agreement between methods ranging from good (ICC = 0.75) to poor (ICC = 0.05). Finally, the accuracy of scar detection by regional strains differed among the 3 FT software. While the accuracy of regional LS was similar, CS by one software was less accurate (AUC 0.68) than tagging (AUC 0.80, p < 0.006) and RS less accurate (AUC 0.578) than the other two (AUC 0.76 and 0.73, p < 0.02) to discriminate segments with LGE. CONCLUSIONS: We confirm good agreement of CMR FT and little intervendor difference for GLS and GCS evaluation, with variable agreement for GRS. For regional strain evaluation, intervendor difference was larger, especially for RS, and the diagnostic performance varied more substantially among different vendors for regional strain analysis.

• MeSH
• funkce levé komory srdeční MeSH
• gadolinium MeSH
• kontrastní látky * MeSH
• lidé MeSH
• magnetická rezonance kinematografická * MeSH
• magnetická rezonanční spektroskopie MeSH
• prediktivní hodnota testů MeSH
• reprodukovatelnost výsledků MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Existing safety standards for electromagnetic radiation in the radio frequency range, including microwave radiation, adopted in the USSR, Great Britain, Poland, Czechoslovakia, USA, Canada, FRG and recommended by IRPA/INIRC are described. It is proposed to use the value 0.4 W/kg as the basic value of an absorbed dose rate which corresponds to the energy flux density 100 W/m2 for frequencies over 2 GHz. The concepts of an effective dose rate and effective dose are discussed. Various questions of how to provide safety of those working with electromagnetic radiations are considered.

• MeSH
• dávka záření MeSH
• maximální přípustná koncentrace MeSH
• mikrovlny MeSH
• radiační ochrana MeSH
• radiometrie normy   MeSH
• rádiové vlny * MeSH
• Publikační typ
• anglický abstrakt MeSH
• časopisecké články MeSH
• srovnávací studie MeSH
• Geografické názvy
• Anglie MeSH
• Československo MeSH
• Kanada MeSH
• Německo západní MeSH
• Polsko MeSH
• Spojené státy americké MeSH
• SSSR MeSH

Objective.This study aims to assess the composition of scattered particles generated in proton therapy for tumors situated proximal to some titanium (Ti) dental implants. The investigation involves decomposing the mixed field and recording Linear Energy Transfer (LET) spectra to quantify the influence of metallic dental inserts located behind the tumor.Approach.A therapeutic conformal proton beam was used to deliver the treatment plan to an anthropomorphic head phantom with two types of implants inserted in the target volume (made of Ti and plastic, respectively). The scattered radiation resulted during the irradiation was detected by a hybrid semiconductor pixel detector MiniPIX Timepix3 that was placed distal to the Spread-out Bragg peak. Visualization and field decomposition of stray radiation were generated using algorithms trained in particle recognition based on artificial intelligence neural networks (AI NN). Spectral sensitive aspects of the scattered radiation were collected using two angular positions of the detector relative to the beam direction: 0° and 60°.Results.Using AI NN, 3 classes of particles were identified: protons, electrons & photons, and ions & fast neutrons. Placing a Ti implant in the beam's path resulted in predominantly electrons and photons, contributing 52.2% of the total number of detected particles, whereas for plastic implants, the contribution was 65.4%. Scattered protons comprised 45.5% and 31.9% with and without metal inserts, respectively. The LET spectra were derived for each group of particles identified, with values ranging from 0.01 to 7.5 keVμm-1for Ti implants/plastic implants. The low-LET component was primarily composed of electrons and photons, while the high-LET component corresponded to protons and ions.Significance.This method, complemented by directional maps, holds the potential for evaluating and validating treatment plans involving stray radiation near organs at risk, offering precise discrimination of the mixed field, and enhancing in this way the LET calculation.

• MeSH
• fantomy radiodiagnostické * MeSH
• lidé MeSH
• lineární přenos energie * MeSH
• neuronové sítě MeSH
• plánování radioterapie pomocí počítače metody   MeSH
• protézy a implantáty MeSH
• protonová terapie * metody   přístrojové vybavení   MeSH
• radiační rozptyl MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH