X, 217 s. : tab., grafy ; 22 cm
Vpráci autoři ověřují, zda při hodnocení stupně závažnosti diabetické retinopatie lzevyužítmetodumatematickéhozpracování obrazusítnicepomocí počítače.Tato metoda je založena na identifikaci cévních zakončení v zobrazené oblasti sítnice. Je stanoven předpoklad, že s růstem závažnosti nálezu roste i počet cévních zakončení ve spojitosti s procesem neogeneze. Ke zjištění počtu cévních zakončení autoři používajímetodiku Adaptive Contrast Control (ACC). Speciálním postupem jsou identifikována cévní zakončení a je stanoven jejich počet na sledované ploše sítnice. Metoda umožňuje určit kromě počtu cévních zakončení také celkovou délku cév, jejich objem, povrch, plochu, kterou pokrývají, a histogram velikosti průměru cév. Bylo vyšetřeno 19 pacientů (38 očí) se zcela fyziologickým nálezem na sítnici. Průměrný věk v souboru byl 37,3 roku. Dále bylo vyšetřeno 10 pacientů (20 očí) se středně pokročilou a pokročilou diabetickou retinopatií a 10 pacientů (20 očí) s rizikovou proliferativní diabetickou retinopatií. U každého pacienta byla provedena standardní digitální fotografie očního pozadí obou očí ve formátu „tif“ a každý ze snímků byl podroben matematické analýze. Soubor pacientů byl rozdělen na 3 skupiny (pacienti s fyziologickým nálezem, nálezem neproliferativní a nálezem proliferativní diabetické retinopatie). Vzávěru autoři prokazují, že se zvyšujícím se stupněmzávažnosti nálezu na retině roste i počet cévních zakončení.
The authors test whether for evaluation of the severity of diabetic retinopathy it is possible to use the method of computer assisted mathematical processing of the retinal image. This method is based on the identification of vascular endings in the visualized part of the retina. It is assumed that with the severity of the finding the number of vascular endings increases in conjunction with the process of neogenesis. For assessment of the number of vascular endings the authors use the Adaptive Contrast Control (ACC) method. By a special procedure the vascular endings are identified and their number is assessed in the investigated area of the retina. The method makes it possible to assess in addition to the number of vascular endings also the total length of the vessels, their volume, surface, area they cover and the The authors examined 19 patients (38 eyes) with a quite normal finding on the retina. The mean age of the group was 37.3 years. Moreover they examined 10 patients (20eyes) with middle advanced and advanced non-proliferative diabetic retinopathy and 10 patients (20 eyes) with risk proliferative diabetic retinopathy. In every patient a standard digital photograph of the fundus of both eyes size "tif" was made and each picture was subjected to mathematical analysis. The group of patients was divided into three sub-groups (patients with a normal finding, a non-proliferative finding and a finding of proliferative diabetic retinopathy). In the conclusion the authors provide evidence that with increasing severity of the finding on the retina also the number of vascular endings increases.
- MeSH
- Diabetic Retinopathy diagnosis classification therapy MeSH
- Research Support as Topic MeSH
- Photography MeSH
- Humans MeSH
- Mathematical Computing MeSH
- Image Processing, Computer-Assisted MeSH
- Retinal Vessels anatomy & histology MeSH
- Severity of Illness Index MeSH
- Check Tag
- Humans MeSH
- Publication type
- Review MeSH
- Comparative Study MeSH
It has been shown that besides positron emission tomography, single photon emission computed tomography and magnetic resonance imaging; contrast echocardiography can be used for qualitative and quantitative myocardial perfusion assessment. In this review, the properties of ultrasound contrast agents, imaging techniques and acquisition methods are shortly described and the possibilities of perfusion echocardiography are summarized. The main focus is put on the description of three perfusion models: mathematical models, physical models assuming an ideal inflow and physical models including inflow measurement.
- MeSH
- Echocardiography MeSH
- Image Interpretation, Computer-Assisted MeSH
- Contrast Media diagnostic use MeSH
- Coronary Circulation MeSH
- Humans MeSH
- Models, Cardiovascular MeSH
- Predictive Value of Tests MeSH
- Myocardial Perfusion Imaging methods MeSH
- Animals MeSH
- Check Tag
- Humans MeSH
- Animals MeSH
- Publication type
- Review MeSH
Wiley series in probability and statistics
1st ed. xxvi, 311 s.
- MeSH
- Medicine MeSH
- Population MeSH
- Regression Analysis MeSH
- Statistics as Topic MeSH
- Health Surveys MeSH
- Conspectus
- Statistika
- NML Fields
- statistika, zdravotnická statistika
- veřejné zdravotnictví
1st ed. xv, 1101 s.
The assessment of age-at-death is an important and challenging part of investigations of human skeletal remains. The main objective of the present study was to apply different mathematical approaches in order to reach more accurate and reliable results in age estimation. A multi-ethnic dataset (n=941) of evaluated age-related changes on the pubic symphysis and the auricular surface of the hip bone was used. Two research groups examined nine different mathematical approaches. The best results were reached by Multi-linear regression, followed by the Collapsed regression model, with MAE values of 9.7 and 9.9 years, respectively, and with RMSE values of 12.1 and 12.2, respectively. The mean accuracy of decision tree models ranged between 30.7% and 72.3%, with the model using only the PUSx indicator performing the best. Moreover, our results indicate that the limiting factor of age estimation can be the visual evaluation of age-related changes. Further research is required to objectify the proposed methods for estimating age.
- MeSH
- Adult MeSH
- Middle Aged MeSH
- Humans MeSH
- Young Adult MeSH
- Neural Networks, Computer MeSH
- Ilium anatomy & histology MeSH
- Decision Trees MeSH
- Aged, 80 and over MeSH
- Aged MeSH
- Models, Statistical * MeSH
- Pubic Symphysis anatomy & histology MeSH
- Body Remains * MeSH
- Age Determination by Skeleton methods MeSH
- Check Tag
- Adult MeSH
- Middle Aged MeSH
- Humans MeSH
- Young Adult MeSH
- Male MeSH
- Aged, 80 and over MeSH
- Aged MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
We study asymptotic behavior of solutions of general advanced differential systems y(t) = F(t, y(t)), where F : Ω → [Symbol: see text] (n) is a continuous quasi-bounded functional which satisfies a local Lipschitz condition with respect to the second argument and Ω is a subset in [Symbol: see text] × C(r)(n), C(r)(n) := C([0, r], [Symbol: see text] (n)), y t [Symbol: see text]C(r)(n), and y t (θ) = y(t + θ), θ [Symbol: see text] [0, r]. A monotone iterative method is proposed to prove the existence of a solution defined for t → ∞ with the graph coordinates lying between graph coordinates of two (lower and upper) auxiliary vector functions. This result is applied to scalar advanced linear differential equations. Criteria of existence of positive solutions are given and their asymptotic behavior is discussed.
- MeSH
- Mathematical Concepts * MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
Sage reference publication
3 sv. : il. ; 29 cm
- MeSH
- Politics MeSH
- Social Sciences methods MeSH
- Government Programs MeSH
- Policy Making MeSH
- Research MeSH
- Investigative Techniques MeSH
- Publication type
- Encyclopedia MeSH
- Conspectus
- Sociologie
- NML Fields
- sociologie
- statistika, zdravotnická statistika
BACKGROUND: Photosynthetic microalgae have been in the spotlight of biotechnological production (biofuels, lipids, etc), however, current barriers in mass cultivation of microalgae are limiting its successful industrialization. Therefore, a mathematical model integrating both the biological and hydrodynamical parts of the cultivation process may improve our understanding of relevant phenomena, leading to further optimization of the microalgae cultivation. RESULTS: We introduce a unified multidisciplinary simulation tool for microalgae culture systems, particularly the photobioreactors. Our approach describes changes of cell growth determined by dynamics of heterogeneous environmental conditions such as irradiation and mixing of the culture. Presented framework consists of (i) a simplified model of microalgae growth in a culture system (the advection-diffusion-reaction system within a phenomenological model of photosynthesis and photoinhibition), (ii) the fluid dynamics (Navier-Stokes equations), and (iii) the irradiance field description (Beer-Lambert law). To validate the method, a simple case study leading to hydrodynamically induced fluctuating light conditions was chosen. The integration of computational fluid dynamics (ANSYS Fluent) revealed the inner property of the system, the flashing light enhancement phenomenon, known from experiments. CONCLUSION: Our physically accurate model of microalgae culture naturally exhibits features of real system, can be applied to any geometry of microalgae mass cultivation and thus is suitable for biotechnological applications.
