32 results on '"Fürst, Tomáš"'
Search Results
2. Crop growth dynamics: Fast automatic analysis of LiDAR images in field-plot experiments by specialized software ALFA.
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Fryčák, Tadeáš, Fürst, Tomáš, Koprna, Radoslav, Špíšek, Zdeněk, Miřijovský, Jakub, and Humplík, Jan F.
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CROP growth , *IMAGE analysis , *ROOT-mean-squares , *NONLINEAR regression , *COMPUTER software , *AGRICULTURAL technology , *SOFTWARE product line engineering - Abstract
Repeated measurements of crop height to observe plant growth dynamics in real field conditions represent a challenging task. Although there are ways to collect data using sensors on UAV systems, proper data processing and analysis are the key to reliable results. As there is need for specialized software solutions for agricultural research and breeding purposes, we present here a fast algorithm ALFA for the processing of UAV LiDAR derived point-clouds to extract the information on crop height at many individual cereal field-plots at multiple time points. Seven scanning flights were performed over 3 blocks of experimental barley field plots between April and June 2021. Resulting point-clouds were processed by the new algorithm ALFA. The software converts point-cloud data into a digital image and extracts the traits of interest–the median crop height at individual field plots. The entire analysis of 144 field plots of dimension 80 x 33 meters measured at 7 time points (approx. 100 million LiDAR points) takes about 3 minutes at a standard PC. The Root Mean Square Deviation of the software-computed crop height from the manual measurement is 5.7 cm. Logistic growth model is fitted to the measured data by means of nonlinear regression. Three different ways of crop-height data visualization are provided by the software to enable further analysis of the variability in growth parameters. We show that the presented software solution is a fast and reliable tool for automatic extraction of plant height from LiDAR images of individual field-plots. We offer this tool freely to the scientific community for non-commercial use. [ABSTRACT FROM AUTHOR]
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- 2024
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3. Does the healthy vaccinee bias rule them all? Association of COVID-19 vaccination status and all-cause mortality from an analysis of data from 2.2 million individual health records.
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Fürst, Tomáš, Bazalová, Angelika, Fryčák, Tadeáš, and Janošek, Jaroslav
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VACCINATION status , *MEDICAL records , *COVID-19 vaccines , *VACCINE effectiveness , *MORTALITY - Abstract
• Analysis based on two independent datasets, total population of approx. 2.2 million. • All-cause mortality (ACM) of vaccinated and unvaccinated against COVID-19. • ACM consistently much lower in freshly vaccinated groups even outside COVID waves. • Healthy vaccinee bias demonstrated on visualizations of the data. • This bias overestimates COVID-19 vaccine efficiency in observational studies. We investigated the validity of claims of the healthy vaccinee effect (HVE) in COVID-vaccine studies by analyzing associations between all-cause mortality (ACM) and COVID-19 vaccination status. Approximately 2.2 million individual records from two Czech health insurance companies were retrospectively analyzed. Each age group was stratified according to the vaccination status (unvaccinated vs. individuals less than 4 weeks vs. more than 4 weeks from Doses 1, 2, 3, and 4 or more doses of vaccine). ACMs in these groups were computed and compared. Consistently over datasets and age categories, ACM was substantially lower in the vaccinated than unvaccinated groups regardless of the presence or absence of a wave of COVID-19 deaths. Moreover, the ACMs in groups more than 4 weeks from Doses 1, 2, or 3 were consistently several times higher than in those less than 4 weeks from the respective dose. HVE appears to be the only plausible explanation for this, which is further corroborated by a created mathematical model. In view of the presence of HVE, the baseline difference in the frailty of vaccinated and unvaccinated populations in periods without COVID-19 must be taken into account when estimating COVID-19 vaccine effectiveness from observational data. [ABSTRACT FROM AUTHOR]
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- 2024
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4. The difference between semi-continuum model and Richards' equation for unsaturated porous media flow.
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Vodák, Rostislav, Fürst, Tomáš, Šír, Miloslav, and Kmec, Jakub
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POROUS materials , *PARTIAL differential equations , *OPERATOR equations , *MULTISCALE modeling , *MATHEMATICAL analysis - Abstract
Semi-continuum modelling of unsaturated porous media flow is based on representing the porous medium as a grid of non-infinitesimal blocks that retain the character of a porous medium. This approach is similar to the hybrid/multiscale modelling. Semi-continuum model is able to physically correctly describe diffusion-like flow, finger-like flow, and the transition between them. This article presents the limit of the semi-continuum model as the block size goes to zero. In the limiting process, the retention curve of each block scales with the block size and in the limit becomes a hysteresis operator of the Prandtl-type used in elasto-plasticity models. Mathematical analysis showed that the limit of the semi-continuum model is a hyperbolic-parabolic partial differential equation with a hysteresis operator of Prandl's type. This limit differs from the standard Richards' equation, which is a parabolic equation and is not able to describe finger-like flow. [ABSTRACT FROM AUTHOR]
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- 2022
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5. A two dimensional semi-continuum model to explain wetting front instability in porous media.
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Kmec, Jakub, Fürst, Tomáš, Vodák, Rostislav, and Šír, Miloslav
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POROUS materials , *FLUID flow , *CONTINUUM mechanics , *PERMEABILITY , *PERCOLATION theory - Abstract
Modelling fluid flow in an unsaturated porous medium is a complex problem with many practical applications. There is enough experimental and theoretical evidence that the standard continuum mechanics based modelling approach is unable to capture many important features of porous media flow. In this paper, a two-dimensional semi-continuum model is presented that combines ideas from continuum mechanics with invasion percolation models. The medium is divided into blocks of finite size that retain the nature of a porous medium. Each block is characterized by its porosity, permeability, and a retention curve. The saturation and pressure of the fluids are assumed to be uniform throughout each block. It is demonstrated that the resulting semi-continuum model is able to reproduce (1) gravity induced preferential flow with a spatially rich system of rivulets (fingers) characterized by saturation overshoot, (2) diffusion-like flow with a monotonic saturation profile, (3) the transition between the two. The model helps to explain the formation of the preferential pathways and their persistence and structure (the core and fringe of the fingers), the effect of the initial saturation of the matrix, and the saturation overshoot phenomenon. [ABSTRACT FROM AUTHOR]
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- 2021
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6. Non-linear diffusion model for optimization of leather manufacturing: Lime extraction from calcimine
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Kolomazník, Karel, Fürst, Tomáš, and Bařinová, Michaela
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Abstract: This paper deals with decantation washing of calcimine (limed collagen splits), one of the valuable by-products of leather manufacturing industry, in order to remove calcium hydroxide from the calcimine inner volume. This process can be mathematically described as diffusion accompanied by desorption. The process of desorption makes the governing equations non-linear. There are two steps to perform the deliming process—the first one is a simple washing of the calcimine in plain water, the second one requires adding a deliming agent. We have worked out a mathematical model that enables us to determine if it is economically and technologically efficient to perform plain water washing or chemical deliming. [Copyright &y& Elsevier]
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- 2010
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7. Diffusion with Nonlinear Adsorption.
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Fürst, Tomáš and Vodák, Rostislav
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DIFFUSION processes , *NONLINEAR statistical models , *STABILIZING agents , *INDUSTRIAL contamination , *CHEMICAL structure , *ASYMPTOTIC expansions , *SOLUTION (Chemistry) - Abstract
This article deals with the mathematical description of the process of washing a contaminant out of a porous material sample. Important applications of this process in the leather-making industry are discussed. Part of the contaminant is held in the porous material by an active chemical bond due to adsorption which makes the governing equations nonlinear. We prove existence and uniqueness of a weak solution to the proposed model and show its stabilization for time converging to infinity. [ABSTRACT FROM AUTHOR]
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- 2009
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8. Full analogy of Sharkovsky's theorem for lower semicontinuous maps
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Andres, Jan, Fürst, Tomáš, and Pastor, Karel
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MATHEMATICAL continuum , *CONTINUITY , *PHILOSOPHY of mathematics , *MATHEMATICAL analysis - Abstract
Abstract: A full analogy of the celebrated Sharkovsky cycle coexistence theorem is established for lower semicontinuous (multivalued) maps on metrizable linear continua. This result is further extended to triangular maps. [Copyright &y& Elsevier]
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- 2008
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9. Nontrivial application of Nielsen theory to differential systems
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Andres, Jan and Fürst, Tomáš
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DIFFERENTIAL equations , *CALCULUS , *SET-valued maps , *MATHEMATICS - Abstract
Abstract: In reply to a problem of Jean Leray concerning application of the Nielsen theory to differential systems for obtaining multiplicity results, we present a nontrivial example of such an application. The emphasis is on the parameter space in order to ensure that no subdomain becomes subinvariant under the related Hammerstein solution operator. To achieve this goal, we develop a general method applicable also for ordinary differential equations with or without uniqueness as well as for upper-Carathéodory differential inclusions. We are not aware that any alternative approach can be employed, even in the single-valued case. [Copyright &y& Elsevier]
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- 2006
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10. Polytrauma na CT - srovnání české a rakouské nemocnice.
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Máchal, David, Špiroch, Petr, Fürst, Tomáš, Heřman, Miroslav, Schovánková, Kateřina Máchalová, and Sedláčková, Zuzana
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LEG injuries , *MOTORCYCLING injuries , *HEAD injuries , *HOSPITAL care , *MOTORCYCLING accidents - Abstract
Purpose: Purpose of our study was to evaluate and compare data of patients examined by standardized CT protocol in FN Olomouc (the Czech Republic) and in hospital in Horn (Austria) in years 2018 and 2019. Special attention was paid to the differences in procedures and results at these two hospitals in both states. Methods: In this retrospective observational study were involved patients examined with CT standardized protocol. Apart to the usual data such as age, sex, date and time of examination, we also collected data of consumption of drugs or alcohol as well as a fact weather was the examination done during a shift. Furthermore, the mechanism of injury and the length of hospitalization were marked. Injuries were classified according to affected body regions and severity of the injury with Abbreviated Injury Scale (AIS) and Injury Severity Score (ISS). Results: From total of 486 patients were more frequent male, in Olomouc they comprised 75% and in Horn 68%. Patients of the Austrian hospital had significantly higher age (52.5 years) than in the Czech one (48 years). Correlation of a head injury and a fall from upright position, correlation of thorax injury and suicides and cycling as well as correlation of lower extremity injury and motorcycle accidents was found. The severity of injury had statistically significant growth with age. Patients at both hospitals were hospitalized with similar ISS, but patients discharged from Horn had ISS significantly higher (4.5) compared to FN Olomouc (1). Conclusions: In the profile of patients and hospital care were no relevant differences in majority of the parameters between both hospitals. Exceptions were higher age of the patients in Horn, as well as the higher average value of ISS in patients discharged home without hospitalization. [ABSTRACT FROM AUTHOR]
- Published
- 2022
11. A Simple Risk Formula for the Prediction of COVID-19 Hospital Mortality.
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Plášek, Jiří, Dodulík, Jozef, Gai, Petr, Hrstková, Barbora, Škrha Jr., Jan, Zlatohlávek, Lukáš, Vlasáková, Renata, Danko, Peter, Ondráček, Petr, Čubová, Eva, Čapek, Bronislav, Kollárová, Marie, Fürst, Tomáš, and Václavík, Jan
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HOSPITAL mortality , *COVID-19 , *RURAL hospitals , *RESPIRATORY infections ,MORTALITY risk factors - Abstract
SARS-CoV-2 respiratory infection is associated with significant morbidity and mortality in hospitalized patients. We aimed to assess the risk factors for hospital mortality in non-vaccinated patients during the 2021 spring wave in the Czech Republic. A total of 991 patients hospitalized between January 2021 and March 2021 with a PCR-confirmed SARS-CoV-2 acute respiratory infection in two university hospitals and five rural hospitals were included in this analysis. After excluding patients with unknown outcomes, 790 patients entered the final analyses. Out of 790 patients included in the analysis, 282/790 (35.7%) patients died in the hospital; 162/790 (20.5) were male and 120/790 (15.2%) were female. There were 141/790 (18%) patients with mild, 461/790 (58.3%) with moderate, and 187/790 (23.7%) with severe courses of the disease based mainly on the oxygenation status. The best-performing multivariate regression model contains only two predictors—age and the patient's state; both predictors were rendered significant (p < 0.0001). Both age and disease state are very significant predictors of hospital mortality. An increase in age by 10 years raises the risk of hospital mortality by a factor of 2.5, and a unit increase in the oxygenation status raises the risk of hospital mortality by a factor of 20. [ABSTRACT FROM AUTHOR]
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- 2024
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12. A semi-continuum model of saturation overshoot in one dimensional unsaturated porous media flow.
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Kmec, Jakub, Fürst, Tomáš, Vodák, Rostislav, and Šír, Miloslav
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A semi-continuum model for fluid flow in saturated-unsaturated porous medium in one spatial dimension is presented. The model is based on well-established physics, measurable parameters and material characteristics. The porous material is characterized by porosity, intrinsic permeability, main wetting and draining branches of the retention curve, and the saturation dependence of the relative permeability. The fluid is characterized by its density and dynamic viscosity. The only physics involved is the mass balance of fluid in porous media together with the Darcy-Buckingham Law for fluid flow in unsaturated porous media. The model is a cellular automaton based on the Macro Modified Invasion Percolation concept of dividing the porous medium into blocks which are not infinitesimal and are assumed to retain the characteristics of a porous medium. The cellular automaton repeats three successive rules: saturation update in each block, pressure update in each block, and flux update between neighboring blocks. The model tracks the evolution of the relative saturation, the fluid capillary pressure, and the fluid flux. The model is shown to reproduce qualitatively and quantitatively all features of one dimensional saturation overshoot behavior reported in the literature. [ABSTRACT FROM AUTHOR]
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- 2019
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13. Cytotoxický edém a jeho vývoj u pacientů s ischemickou cévní mozkovou příhodou v zadním povodí.
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Čivrný, Jakub, Dorňák, Tomáš, Fürst, Tomáš, Heřman, Miroslav, and Černá, Marie
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STROKE patients , *BRAIN evolution , *EDEMA , *THROMBOLYTIC therapy , *STROKE - Abstract
Aim: The aim of the study was to examine early ischemic changes evolution on brain MRI as a possible predictor of treatment success in posterior circulation ischemic stroke patients treated with intravenous thrombolysis (IVT) and/or mechanical thrombectomy (MT). Methods: We investigated 106 patients with posterior circulation acute ischemic stroke symptoms treated with IVT alone or IVT and MT. Both initial and early follow-up imaging was evaluated. DWI/FLAIR mismatch was evaluated in 95 patients of known time of onset. Extent end evolution of cytotoxic edema was compared with clinical outcome. Three-month modified Rankin Scale was used to measure the clinical outcome. Results: The average time of symptom duration in a subgroup with known time of onset (95 out of 106 patients) was 160 minutes (median 140, variance 40-500). DWI/FLAIR mismatch was typical in patients with symptoms duration less than 2 hours. DWI/FLAIR mismatch was present only in approximately half (13/27, 48,2%) of the patients with symptoms duration more than 3 hours. DWI/FLAIR mismatch negative patients had surprisingly better clinical outcome compared to DWI/FLAIR mismatch positive group, although the result was not statistically significant (p = 0.08). We did not find a single case of total cytotoxic edema reversibility on follow-up MRI. We detected T2 hyperintensity on all follow-up MRIs. Conclusion: DWI/FLAIR mismatch may help specify time of onset in patients with unknown duration of acute ischemic stroke symptoms. Neither extent nor evolution of cytotoxic edema predicts early response to a therapy or a good clinical outcome. Cytotoxic edema reversal was rare. We did not find a single case of complete cytotoxic edema resolution. [ABSTRACT FROM AUTHOR]
- Published
- 2019
14. Ultrazvukové hodnocení uzlů štítné žlázy včetně shear wave elastografie.
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Sedláčková, Zuzana, Heřman, Jan, Fürst, Tomáš, Salzman, Richard, and Heřman, Miroslav
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THYROID nodules , *ELASTOGRAPHY , *LYMPH nodes , *CANCER , *BIOPSY - Abstract
Aim: To find the best combination of parameters for diagnosing malignant thyroid nodules and for the assessment of possible benefit of shear-wave elastography. Methods: We performed an ultrasonographic examination of thyroid nodules in 89 patients indicated for biopsy. We evaluated epidemiologic and ultrasonographic data including elastography. Results: Malignant thyroid nodules prevailed statistically significantly in men and in patients with enlarged lymph nodes. Malignant nodules had irregular margins, were bigger, and were associated with microcalcifications. We found statistically significantly higher stiffness and lower minimum stiffness in malignant tumors during elastographic measurements. The sensitivity and specificity of ultrasound parameters without elastography were 86% and 84%, respectively; the values did not change after adding elastography. Conclusion: The assessment of classic ultrasonographic parameters was sufficient for diagnosis and the addition of elastographic parameters did not improve the results. [ABSTRACT FROM AUTHOR]
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- 2019
15. The Role of Ultrasound and Shear-Wave Elastography in Evaluation of Cervical Lymph Nodes.
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Heřman, Jan, Sedláčková, Zuzana, Fürst, Tomáš, Vachutka, Jaromír, Salzman, Richard, Vomáčka, Jaroslav, and Heřman, Miroslav
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HEAD tumors , *NECK tumors , *DOPPLER ultrasonography , *AGE distribution , *DIAGNOSTIC imaging , *LYMPH nodes , *SEX distribution , *PATHOLOGIC neovascularization , *CALCINOSIS , *DIAGNOSIS - Abstract
Aim. To evaluate the prognostic value of ultrasound and shear-wave elastography (SWE) in diagnosing malignant cervical lymph nodes. Methods. A total of 99 patients with enlarged lymph nodes (99 lymph nodes presenting as a neck mass) were examined clinically with conventional ultrasound including Doppler examination and shear-wave elastography. The results of the examinations were compared with the final diagnosis. Results. There were 43 benign and 56 malignant lymph nodes in our cohort. Age and sex were significant predictors of malignancy. The standard ultrasound parameters—node size, long/short axis ratio, hilum, vascularization, and the presence of microcalcifications—were also statistically significant. Lymph node volume combined with age showed the best predictive power. The maximum stiffness found on SWE was also a significant predictor of malignancy. The combination of epidemiologic, classic ultrasound, and elastographic parameters yielded the highest sensitivity and specificity in the prediction of malignancy; however, the additional impact of elastographic parameters was low. Conclusion. A combination of epidemiologic and classic ultrasound parameters can discriminate between malignant and benign lymph nodes with satisfactory sensitivity and specificity. Examining the stiffness of lymph nodes by means of SWE does not add much new predictive power. [ABSTRACT FROM AUTHOR]
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- 2019
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16. More Analyses are Needed to Evaluate the Effectiveness of Protection by Vaccines and Previous Infection Against the Omicron Variant of SARS-CoV-2.
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Vencálek, Ondřej, Beran, Jiří, Fürst, Tomáš, Krátká, Zuzana, and Komárek, Arnošt
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To theEditor - We have read with interest the article "Protection by vaccines and previous infection against the Omicron variant of SARS-CoV-2" by Smíd et al [[1]]. Calculations including children and young adults, whose COVID-19 hospitalization rates and severe outcomes are low, dilute the true protective effects of vaccination/previous infection. [Extracted from the article]
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- 2022
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17. Vitamin D 3 Supplementation: Comparison of 1000 IU and 2000 IU Dose in Healthy Individuals.
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Dědečková, Eva, Viták, Roman, Jirásko, Michal, Králová, Markéta, Topolčan, Ondřej, Pecen, Ladislav, Fürst, Tomáš, Brož, Pavel, and Kučera, Radek
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DIETARY supplements , *VITAMIN D deficiency , *CHOLECALCIFEROL , *VITAMIN D - Abstract
Background: Scientific studies point to a significant global vitamin D deficiency. The recommended dose of vitamin D for the adult population in Central Europe is 800–2000 IU/day. The aim of our study was to determine whether doses of 1000 IU or 2000 IU of vitamin D3 are adequate to achieve the sufficiency reference values of [25(OH)D]. Methods: Seventy-two healthy volunteers, average age twenty-two, took part in the study. The study was conducted from October to March in order to eliminate intra-dermal vitamin D production. Vitamin D3 in an oleaginous mixture was used. The participants used either 1000 IU or 2000 IU/daily for two 60-day periods with a 30-day break. Results: The dose of 1000 IU, taken for 60 days, increased vitamin D levels relatively little. Furthermore, serum vitamin D levels decreased in the 30 days following the cessation of supplementation. Taking 2000 IU daily led to a sharp increase in serum levels which plateaued 30 days after the subjects stopped using vitamin D3 drops. Conclusions: Both doses, taken daily, can help maintain adequate vitamin D levels during the winter months. A daily dose of 2000 IU, however, maintained the desired levels of vitamin D for a longer period. [ABSTRACT FROM AUTHOR]
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- 2023
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18. A kinetics study of the simultaneous methanolysis and hydrolysis of triglycerides.
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Pecha, Jiří, Šánek, Lubomír, Fürst, Tomáš, and Kolomazník, Karel
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METHANOLYSIS , *TRIGLYCERIDES , *HYDROLYSIS , *CHEMICAL kinetics , *FATTY acid methyl esters , *AMMONIUM hydroxide - Abstract
Transesterification of triglycerides (oils and fats) catalyzed by bases is a common method for production of fatty acid methyl esters (FAME) – a renewable fuel (biodiesel) and basic oleochemical. Hydrolysis of esters – saponification – represents the main side reaction. Saponification leads to catalyst deactivation and impedes products purification. In this work, kinetics of the competing triglyceride hydrolysis and methanolysis (i.e. transesterification) is investigated. Furthermore, an alternative organic catalyst – tetramethylammonium hydroxide (TMAH) – is compared with potassium hydroxide and sodium methoxide. TMAH is less active but the methanolysis is more selective towards FAME formation and hydrolysis proceeds at a slower rate in comparison to the inorganic catalysts. FAME are less susceptible to hydrolysis than glycerides. A simple mathematical model assuming irreversibility of all reactions is capable to describe the measured data well (40–60 °C, TMAH concentration 0.5–1.5 w TMAH /w oil , molar ratio methanol:oil = 6). [ABSTRACT FROM AUTHOR]
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- 2016
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19. Indeterminacy of the Diagnosis of Sudden Infant Death Syndrome Leading to Problems with the Validity of Data.
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Olecká, Ivana, Dobiáš, Martin, Lemrová, Adéla, Ivanová, Kateřina, Fürst, Tomáš, Krajsa, Jan, and Handlos, Petr
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SUDDEN infant death syndrome , *MEDICAL quality control , *INFANT mortality , *DIAGNOSIS , *HEALTH policy - Abstract
The validity of infant mortality data is essential in assessing health care quality and in the setting of preventive measures. This study explores different diagnostic procedures used to determine the cause of death across forensic settings and thus the issue of the reduced validity of data. All records from three forensic medical departments that conducted autopsies on children aged 12 months or younger (n = 204) who died during the years 2007–2016 in Moravia were included. Differences in diagnostic procedures were found to be statistically significant. Each department works with a different set of risk factors and places different emphasis on different types of examination. The most significant differences could be observed in sudden infant death syndrome and suffocation diagnosis frequency. The validity of statistical data on the causes of infant mortality is thus significantly reduced. Therefore, the possibilities of public health and social policy interventions toward preventing sudden and unexpected infant death are extraordinarily complicated by this lack of data validity. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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20. Automated integrative high-throughput phenotyping of plant shoots: a case study of the cold-tolerance of pea (Pisum sativum L.).
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Humplík, Jan F., Lazár, DuŠan, Fürst, TomáŠ, Husičková, Alexandra, Hýbl, Miroslav, and Spíchal, LukáŠ
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PEAS , *PLANT growth , *PLANT shoots , *CHLOROPHYLL spectra , *PHOTOSYNTHESIS , *SALINITY , *IMAGE analysis software - Abstract
Background: Recently emerging approaches to high-throughput plant phenotyping have discovered their importance as tools in unravelling the complex questions of plant growth, development and response to the environment, both in basic and applied science. High-throughput methods have been also used to study plant responses to various types of biotic and abiotic stresses (drought, heat, salinity, nutrient-starving, UV light) but only rarely to cold tolerance. Results: We present here an experimental procedure of integrative high-throughput in-house phenotyping of plant shoots employing automated simultaneous analyses of shoot biomass and photosystem II efficiency to study the cold tolerance of pea (Pisum sativum L.). For this purpose, we developed new software for automatic RGB image analysis, evaluated various parameters of chlorophyll fluorescence obtained from kinetic chlorophyll fluorescence imaging, and performed an experiment in which the growth and photosynthetic activity of two different pea cultivars were followed during cold acclimation. The data obtained from the automated RGB imaging were validated through correlation of pixel based shoot area with measurement of the shoot fresh weight. Further, data obtained from automated chlorophyll fluorescence imaging analysis were compared with chlorophyll fluorescence parameters measured by a non-imaging chlorophyll fluorometer. In both cases, high correlation was obtained, confirming the reliability of the procedure described. Conclusions: This study of the response of two pea cultivars to cold stress confirmed that our procedure may have important application, not only for selection of cold-sensitive/tolerant varieties of pea, but also for studies of plant cold-response strategies in general. The approach, provides a very broad tool for the morphological and physiological selection of parameters which correspond to shoot growth and the efficiency of photosystem II, and is thus applicable in studies of various plant species and crops. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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21. Mathematical Modelling of Crack Fractography after Implant Failure of Titanium 4.5 LCP Used for Flexible Bridging Osteosynthesis in a Miniature Pig.
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Nečas, Alois, Urbanová, Lucie, Fürst, Tomáš, Ženčák, Pavel, and Tuček, Pavel
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INTERNAL fixation in fractures , *FRACTOGRAPHY , *TITANIUM , *MEDICAL equipment reliability , *BIOMECHANICS , *MESENCHYMAL stem cells , *MINIATURE pigs as laboratory animals , *MATHEMATICAL models in medicine - Published
- 2010
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22. Blurred image restoration: A fast method of finding the motion length and angle
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Dobeš, Michal, Machala, Libor, and Fürst, Tomáš
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IMAGE reconstruction , *FOURIER transforms , *PHOTOGRAPHS , *IMAGE quality analysis , *POWER spectra , *IMAGE processing - Abstract
Abstract: Motion blur in photographic images is a result of camera movement or shake. Methods such as Blind Deconvolution are used when information about the direction and size of blur is not known. Restoration methods, such as Lucy and Richardson or Wiener reconstruction use information about the direction and size of the blur in the deconvolution kernel (called Point Spread Function — PSF). Correct and fast determination of the direction and size of blur improves the quality of restoration and it can substantially reduce the computational time. In this article, a fast method for finding the direction and size of the blur automatically is presented. The method is based on computation of the power spectrum of the image gradient in the frequency domain. The method has achieved good results on both types of images: artificially blurred and naturally blurred (by the camera shake). [Copyright &y& Elsevier]
- Published
- 2010
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23. Measurement of saturation overshoot under grass cover.
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Šír, Miloslav, Lichner, Ľubomír, Kmec, Jakub, Fürst, Tomáš, and Vodák, Rostislav
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SEEPAGE , *SOIL moisture , *NUCLEAR counters , *SOIL infiltration , *IODINE isotopes , *SEA level , *RADIOACTIVE tracers - Abstract
The paper deals with non-destructive measurement of water infiltration into homogenous soil (Haplic Chernozem) covered by grass. The experimental site was located in Most pri Bratislave (Slovakia) in the Pannonian Basin at a height of 130 m above sea level. Radioactive tracer technique was used to determine the water content of the soil profile during water infiltration. A mixture of the radioactive iodine 131I (chemical form Na131I) and the NaI solution was used as a tracer. The tracer distribution in the soil was measured by the Geiger-Müller detector connected to the nuclear analyser. Gravity-driven fingers were detected in the soil under the grass cover as a consequence of the wetting front instability. The instability manifested itself as a non-monotonic moisture profile caused by saturation overshoot and a varying discharge from the soil profile in time. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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24. Bayesian approach for analysis of time-to-event data in plant biology.
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Humplík, Jan F., Dostál, Jakub, Ugena, Lydia, Spíchal, Lukáš, De Diego, Nuria, Vencálek, Ondřej, and Fürst, Tomáš
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BAYESIAN analysis , *DATA analysis , *GERMINATION , *PLANT growth , *BIOLOGY , *SEEDLINGS - Abstract
Background: Plants, like all living organisms, metamorphose their bodies during their lifetime. All the developmental and growth events in a plant's life are connected to specific points in time, be it seed germination, seedling emergence, the appearance of the first leaf, heading, flowering, fruit ripening, wilting, or death. The onset of automated phenotyping methods has brought an explosion of such time-to-event data. Unfortunately, it has not been matched by an explosion of adequate data analysis methods. Results and discussion: In this paper, we introduce the Bayesian approach towards time-to-event data in plant biology. As a model example, we use seedling emergence data of maize under control and stress conditions but the Bayesian approach is suitable for any time-to-event data (see the examples above). In the proposed framework, we are able to answer key questions regarding plant emergence such as these: (1) Do seedlings treated with compound A emerge earlier than the control seedlings? (2) What is the probability of compound A increasing seedling emergence by at least 5 percent? Conclusion: Proper data analysis is a fundamental task of general interest in life sciences. Here, we present a novel method for the analysis of time-to-event data which is applicable to many plant developmental parameters measured in field or in laboratory conditions. In contrast to recent and classical approaches, our Bayesian computational method properly handles uncertainty in time-to-event data and it is capable to reliably answer questions that are difficult to address by classical methods. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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25. Estimating heat tolerance of plants by ion leakage: a new method based on gradual heating.
- Author
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Ilík, Petr, Špundová, Martina, Melkovičová, Helena, Kučerová, Zuzana, Krchňák, Pavel, Šicner, Michal, Panzarová, Klára, Benediktyová, Zuzana, Trtílek, Martin, Fürst, Tomáš, and Večeřová, Kristýna
- Subjects
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PLANTS , *IONS , *CELL membranes , *HEAT treatment , *ELECTRIC conductivity - Abstract
Summary: Heat tolerance of plants related to cell membrane thermostability is commonly estimated via the measurement of ion leakage from plant segments after defined heat treatment. To compare heat tolerance of various plants, it is crucial to select suitable heating conditions. This selection is time‐consuming and optimizing the conditions for all investigated plants may even be impossible. Another problem of the method is its tendency to overestimate basal heat tolerance. Here we present an improved ion leakage method, which does not suffer from these drawbacks. It is based on gradual heating of plant segments in a water bath or algal suspensions from room temperature up to 70–75°C. The electrical conductivity of the bath/suspension, which is measured continuously during heating, abruptly increases at a certain temperature
T COND (within 55–70°C). TheT COND value can be taken as a measure of cell membrane thermostability, representing the heat tolerance of plants/organisms. HigherT COND corresponds to higher heat tolerance (basal or acquired) connected to higher thermostability of the cell membrane, as evidenced by the common ion leakage method. The new method also enables determination of the thermostability of photochemical reactions in photosynthetic samples via the simultaneous measurement of Chl fluorescence. [ABSTRACT FROM AUTHOR]- Published
- 2018
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26. PROSTÝ SNÍMEK LBI U PORANĚNÍ HLAVY.
- Author
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Sedláčková, Zuzana, Mitrovičová, Diana, Heřman, Jan, and Fürst, Tomáš
- Abstract
Aim: CT examination is the gold standard for imaging patients after head injury with high and medium risk of brain trauma. Czech guidelines, unlike the European ones, acknowledge skull X-ray in the case of moderate trauma as well (although CT is preferred). We focused on patients who underwent skull X-ray examinations in order to determine whether this method of imaging should still be used, what its significance is, or whether it is time to change the indication criteria in our country. Methods: We retrospectively reviewed the data of 2,349 patients with skull X-ray performed after mild or moderate head injury. We calculated the total sum of traumatic findings and recorded accessible information about patients. Results: Skull X-rays were most frequently performed in children younger than five years of age. Altogether 68 abnormalities were described on X-ray. Out of 16 patients with traumatic changes in the neurocranium, five young children were sent for observation to the pediatric department; the remaining patients had a CT scan that confirmed five fissures, including one with subdural hematoma. Conclusion: Patients with suspected brain injury are indicated for CT examination. Skull X-rays in our study group revealed only a low number of traumatic changes, with most of them found in the splanchnocranium. Czech radiology indication cri teria allowing skull X-rays in patients after head trauma with moderate risk of brain injury should be updated to correspond to the European guidelines, i.e. skull X-rays after head injury should not be indicated. [ABSTRACT FROM AUTHOR]
- Published
- 2017
27. Differential Diagnosis of Parotid Gland Tumors: Role of Shear Wave Elastography.
- Author
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Heřman, Jan, Sedláčková, Zuzana, Vachutka, Jaromír, Fürst, Tomáš, Salzman, Richard, Vomáčka, Jaroslav, and Heřman, Miroslav
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ADENOMA , *SQUAMOUS cell carcinoma , *DOPPLER ultrasonography , *CANCER patients , *DIFFERENTIAL diagnosis , *DIAGNOSTIC imaging , *LONGITUDINAL method , *LYMPH nodes , *LYMPHOMAS , *MELANOMA , *RESEARCH funding , *SALIVARY gland tumors , *CERVICAL plexus , *DIAGNOSIS ,PAROTID gland tumors - Abstract
Aim. To create a predictive score for the discrimination between benign and malignant parotid tumors using elastographic parameters and to compare its sensitivity and specificity with standard ultrasound. Methods. A total of 124 patients with parotid gland lesions for whom surgery was planned were examined using conventional ultrasound, Doppler examination, and shear wave elastography. Results of the examinations were compared with those ones of histology. Results. There were 96 benign and 28 malignant lesions in our cohort. Blurred tumor margin alone proved to be an excellent predictor of malignancy with the sensitivity of 79% and specificity of 97%. Enlarged cervical lymph nodes, tumor vascularisation, microcalcifications presence, homogeneous echogenicity, and bilateral occurrence also discriminated between benign and malignant tumors. However, their inclusion in a predictive model did not improve its performance. Elastographic parameters (the stiffness maxima and minima ratio being the best) also exhibited significant differences between benign and malignant tumors, but again, their inclusion did not significantly improve the predictive power of the blurred margin classifier. Conclusion. Even though elastography satisfactorily distinguishes benign from malignant lesions on its own, it hardly provides any additional value in evaluation of biological character of parotid gland tumors when used as an adjunct to regular ultrasound examination. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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28. Frontline intensive chemotherapy improves outcome in young, high-risk patients with follicular lymphoma: pair-matched analysis from the Czech Lymphoma Study Group Database.
- Author
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Procházka, Vít, Papajík, Tomáš, Janíková, Andrea, Belada, David, Kozák, Tomáš, Šálek, David, Sýkorová, Alice, Móciková, Heidi, Campr, Vít, Dlouhá, Jitka, Langová, Kateřina, Fürst, Tomáš, and Trněný, Marek
- Subjects
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LYMPHOMA treatment , *AUTOTRANSPLANTATION , *CANCER chemotherapy , *PROGNOSIS , *RITUXIMAB - Abstract
Optimal frontline treatment in younger high tumor-burden risk follicular lymphoma patients remains a challenge given the reduced efficacy of standard immunochemotherapy (R-CHOP) in widespread disease and unclear role of intensive induction. The retrospective non-randomized pair-matched (1:3) analysis compared 48 intermediate/high Follicular Lymphoma International Prognostic Index (FLIPI) patients receiving intensive rituximab sequential chemotherapy (R-SQ) with 144 random controls (R-CHOP) matched for age, FLIPI score, and maintenance delivery. Complete response rates were 91.7% and 74.1%, respectively (p = .038). After a median follow-up of 8.8 (R-SQ) and 6.5 years (R-CHOP), 5-year time to treatment failure, progression-free survival, and overall survival were 80.9%, 83.2%, and 100% and 57.5%, 60.3%, and 92.1% (p = .0044;p = .0047;p = .22), respectively. Intensive treatment was accompanied by higher acute hematologic toxicity and infections, comparable non-hematologic toxicity, and incidence of secondary malignancies. Intensive induction demonstrates superior long-term disease control compared to R-CHOP, with higher acute hematologic toxicity, but without acute treatment-related mortality. Further studies are needed to define ultra-high-risk FL patients benefiting most from treatment intensity. [ABSTRACT FROM PUBLISHER]
- Published
- 2017
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29. A New Prognostic Score for Elderly Patients with Diffuse Large B-Cell Lymphoma Treated with R-CHOP: The Prognostic Role of Blood Monocyte and Lymphocyte Counts Is Absent.
- Author
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Procházka, Vít, Pytlík, Robert, Janíková, Andrea, Belada, David, Šálek, David, Papajík, Tomáš, Campr, Vít, Fürst, Tomáš, Furstova, Jana, and Trněný, Marek
- Subjects
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B cell lymphoma , *LYMPHOMA treatment , *MONOCYTES , *OLDER patients , *HEMATOLOGIC malignancies , *RETROSPECTIVE studies - Abstract
Background: Absolute lymphocyte count (ALC) and absolute monocyte count (AMC) have been documented as independent predictors of survival in patients with newly diagnosed Diffuse Large B-cell Lymphoma (DLBCL). Analysis of the prognostic impact of ALC and AMC in the context of International Prognostic Index (IPI) and other significant variables in elderly population treated in the R-CHOP regime has not been carried out yet. Methodology/Principal Findings: In this retrospective study, a cohort of 443 newly diagnosed DLBCL patients with age ≥60 was analyzed. All patients were treated with the R-CHOP therapy. An extensive statistical analysis was performed to identify risk factors of 3-year overall survival (OS). In multivariate analysis, only three predictors proved significant: Eastern Cooperative Oncology Group performance status (ECOG), age and bulky disease presence. These predictors were dichotomized (ECOG ≥1, age ≥70, bulk ≥7.5) to create a novel four-level score. This score predicted 3-year OS of 94.0%, 77.4%, 62.7% and 35.4% in the low-, low-intermediate, high-intermediate and high-risk groups, respectively (P<0.001). Further, a three-level score was tested which stratifies the population better (3-year OS: 91.9%, 67.2%, 36.2% in the low, intermediate and high-risk groups, respectively) but is more difficult to interpret. Both the 3- and 4-level scores were compared to standard scoring systems and, in our population, were shown to be superior in terms of patients risk stratification with respect to 3-year OS prediction. The results were successfully validated on an independent cohort of 162 patients of similar group characteristics. Conclusions: The prognostic role of baseline ALC, AMC or their ratio (LMR) was not confirmed in the multivariate context in elderly population with DLBCL treated with R-CHOP. The newly proposed age-specific index stratifies the elderly population into risk groups more precisely than the conventional IPI and its existing variants. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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30. Five Commercial Immunoassays for SARS-CoV-2 Antibody Determination and Their Comparison and Correlation with the Virus Neutralization Test.
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Šimánek, Václav, Pecen, Ladislav, Krátká, Zuzana, Fürst, Tomáš, Řezáčková, Hana, Topolčan, Ondřej, Fajfrlík, Karel, Sedláček, Dalibor, Šín, Robin, Pazdiora, Petr, Zelená, Hana, Slouka, David, and Kučera, Radek
- Subjects
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NEUTRALIZATION tests , *SARS-CoV-2 , *CONVALESCENT plasma , *COVID-19 , *IMMUNOASSAY - Abstract
There is an ongoing debate as to whether SARS-CoV-2 antibodies can be found in patients who have recovered from COVID-19 disease. Currently, there is no consensus on whether the antibodies, if present, are protective. Our regular measurements of SARS-CoV-2 antibodies, starting in July 2020, have provided us with the opportunity of becoming acquainted with the five different immunoassays. A total of 149 patients were enrolled in our study. We measured the samples using each immunoassay, then performing a virus neutralization test and comparing the results of SARS-CoV-2 antibodies with this test. We observed that the production of neutralizing antibodies is age-dependent. Elderly patients have a higher proportion of high neutralizing titers than young patients. Based on our results, and in combination with the literature findings, we can conclude that the serological SARS-CoV-2 antibody measurement is a helpful tool in the fight against COVID-19. The assays can provide information about the patient's previous contact with the virus. Anti-spike protein assays correlate well with the virus neutralization test and can be used in the screening of potential convalescent plasma donors. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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31. Correction to: "Measurement of saturation overshoot under grass cover" by Miloslav Šír et al.
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Šír, Miloslav, Lichner, Ľubomír, Kmec, Jakub, Fürst, Tomáš, and Vodák, Rostislav
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RADIOACTIVE tracers , *GRASSES - Abstract
The original version of the article was published in Biologia 75 (6): ...–... (2020), 10.2478/s11756-020-00477-z. Unfortunately, Eq. (1) is missing in the Methods section of original version of this article. Here we display this equation. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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32. Use of image-based automated high-throughput screening bioassays and integrative phenotyping in plant biotechnology.
- Author
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Spíchal, Lukáš, Humplík, Jan, De Diego, Nuria, and Fürst, Tomáš
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PLANT biotechnology research , *PLANT growth , *EFFECT of stress on plants , *BIOLOGICAL assay , *PHENOTYPES - Published
- 2016
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