60 research outputs found

    Registration and Fusion of the Autofluorescent and Infrared Retinal Images

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    This article deals with registration and fusion of multimodal opththalmologic images obtained by means of a laser scanning device (Heidelberg retina angiograph). The registration framework has been designed and tested for combination of autofluorescent and infrared images. This process is a necessary step for consecutive pixel level fusion and analysis utilizing information from both modalities. Two fusion methods are presented and compared

    Retrospective Illumination Correction of Retinal Images

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    A method for correction of nonhomogenous illumination based on optimization of parameters of B-spline shading model with respect to Shannon's entropy is presented. The evaluation of Shannon's entropy is based on Parzen windowing method (Mangin, 2000) with the spline-based shading model. This allows us to express the derivatives of the entropy criterion analytically, which enables efficient use of gradient-based optimization algorithms. Seven different gradient- and nongradient-based optimization algorithms were initially tested on a set of 40 simulated retinal images, generated by a model of the respective image acquisition system. Among the tested optimizers, the gradient-based optimizer with varying step has shown to have the fastest convergence while providing the best precision. The final algorithm proved to be able of suppressing approximately 70% of the artificially introduced non-homogenous illumination. To assess the practical utility of the method, it was qualitatively tested on a set of 336 real retinal images; it proved the ability of eliminating the illumination inhomogeneity substantially in most of cases. The application field of this method is especially in preprocessing of retinal images, as preparation for reliable segmentation or registration

    The Use of the Imperialist Competitive Algorithm in Optimising the Setting of the Tram Speed Controller in the Development of a Matlab-Simulink Environment

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    Estimating the electric power used by railway vehicles is an important factor in the planning of future power consumption, looking for possibilities to reduce the use of electric power and therefore also reduce carbon emissions. To improve the estimation, we used the imperialist competitive algorithm in the optimisation process of a mathematical model of a tram vehicle. Specifically, in the setting of the proportional and summation constant of the vehicle speed controller which emulates the activity of the driver in the simulation. Our work presents a new approach to optimising the estimation of energy consumption in tram transport. The method used is based on mathematical modelling and simulation of social development in human society. To obtain the input data for the simulation, we performed a measurement of the reference speed by means of a GPS receiver located in a sample tram vehicle. Subsequently, to verify the model and energy calculation results, we measured the output currents and voltage from the traction converter station at the corresponding time. Our method achieved a 93 % match between the measured and simulated power consumption

    Proteomic and transcriptomic analysis of heart failure due to volume overload in a rat aorto-caval fistula model provides support for new potential therapeutic targets - monoamine oxidase A and transglutaminase 2

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    <p>Abstract</p> <p>Background</p> <p>Chronic hemodynamic overloading leads to heart failure (HF) due to incompletely understood mechanisms. To gain deeper insight into the molecular pathophysiology of volume overload-induced HF and to identify potential markers and targets for novel therapies, we performed proteomic and mRNA expression analysis comparing myocardium from Wistar rats with HF induced by a chronic aorto-caval fistula (ACF) and sham-operated rats harvested at the advanced, decompensated stage of HF.</p> <p>Methods</p> <p>We analyzed control and failing myocardium employing iTRAQ labeling, two-dimensional peptide separation combining peptide IEF and nano-HPLC with MALDI-MS/MS. For the transcriptomic analysis we employed Illumina RatRef-12v1 Expression BeadChip.</p> <p>Results</p> <p>In the proteomic analysis we identified 2030 myocardial proteins, of which 66 proteins were differentially expressed. The mRNA expression analysis identified 851 differentially expressed mRNAs.</p> <p>Conclusions</p> <p>The differentially expressed proteins confirm a switch in the substrate preference from fatty acids to other sources in the failing heart. Failing hearts showed downregulation of the major calcium transporters SERCA2 and ryanodine receptor 2 and altered expression of creatine kinases. Decreased expression of two NADPH producing proteins suggests a decreased redox reserve. Overexpression of annexins supports their possible potential as HF biomarkers. Most importantly, among the most up-regulated proteins in ACF hearts were monoamine oxidase A and transglutaminase 2 that are both potential attractive targets of low molecular weight inhibitors in future HF therapy.</p

    Toll-like receptor signaling in thymic epithelium controls monocyte-derived dendritic cell recruitment and Treg generation

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    The development of thymic regulatory T cells (Treg) is mediated by Aire-regulated self-antigen presentation on medullary thymic epithelial cells (mTECs) and dendritic cells (DCs), but the cooperation between these cells is still poorly understood. Here we show that signaling through Toll-like receptors (TLR) expressed on mTECs regulates the production of specific chemokines and other genes associated with post-Aire mTEC development. Using single-cell RNA-sequencing, we identify a new thymic CD14(+)Sirp alpha (+) population of monocyte-derived dendritic cells (CD14(+)moDC) that are enriched in the thymic medulla and effectively acquire mTEC-derived antigens in response to the above chemokines. Consistently, the cellularity of CD14(+)moDC is diminished in mice with MyD88-deficient TECs, in which the frequency and functionality of thymic CD25(+)Foxp3(+) Tregs are decreased, leading to aggravated mouse experimental colitis. Thus, our findings describe a TLR-dependent function of mTECs for the recruitment of CD14(+)moDC, the generation of Tregs, and thereby the establishment of central tolerance. Immune tolerance is mediated by the deletion of autoreactive T cells via medullary thymic epithelial cells (mTEC) and dendritic cells (DC), and by the induction of regulatory T cells (Treg). Here the authors show that mTEC receiving toll-like receptor signaling control the recruitment of CD14(+)Sirp alpha (+) DC population that is capable of inducing Treg for establishing tolerance

    FOTOTOXICKÝ VLIV PORFYRINOVÝCH SENSITIZERƼ A VIDITELNÉHO ZÁƘENÍ NA GRAM-POZITIVNÍ METHICILIN-REZISTENTNÍ KMEN S. AUREUS

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    The use of antimicrobial photodynamic therapy (aPDT) as a therapeutic modality for the treatment of localized microbial infections represents an developing new field. The emergence of strains resistant to antibiotics has provided the necessary impulse for new drug or technology discoveries to combat these resistant compounds. Although the aPDT is still in infancy, its need is still growing. Like PDT, main components of antimicrobial photodynamic therapy are appropriate light, dye called photosensitizer and created reactive oxygen species. In this article photosensitizers TMPyP and ZnTPPS4 are investigated for antimicrobial photodynamic therapy. We tested these porphyrins on bacterial methicilin – resistant strain MRSA alone and bound in complex created with hp-ÎČ-cyclodextrin. The light emitting diodes (414 nm) were used at the doses 0 and 150 J/cm2. Tested concentrations were from 0.78 to 100 ÎŒM. This experimental work predicated that TMPyP is very successful compound in aPDT. In contrary to ZnTPPS4 which was efficient for eradication of tested gram-positive bacteria only in higher concentrations

    Novel markers for differentiation of lobular and ductal invasive breast carcinomas by laser microdissection and microarray analysis

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    BACKGROUND: Invasive ductal and lobular carcinomas (IDC and ILC) are the most common histological types of breast cancer. Clinical follow-up data and metastatic patterns suggest that the development and progression of these tumors are different. The aim of our study was to identify gene expression profiles of IDC and ILC in relation to normal breast epithelial cells. METHODS: We examined 30 samples (normal ductal and lobular cells from 10 patients, IDC cells from 5 patients, ILC cells from 5 patients) microdissected from cryosections of ten mastectomy specimens from postmenopausal patients. Fifty nanograms of total RNA were amplified and labeled by PCR and in vitro transcription. Samples were analysed upon Affymetrix U133 Plus 2.0 Arrays. The expression of seven differentially expressed genes (CDH1, EMP1, DDR1, DVL1, KRT5, KRT6, KRT17) was verified by immunohistochemistry on tissue microarrays. Expression of ASPN mRNA was validated by in situ hybridization on frozen sections, and CTHRC1, ASPN and COL3A1 were tested by PCR. RESULTS: Using GCOS pairwise comparison algorithm and rank products we have identified 84 named genes common to ILC versus normal cell types, 74 named genes common to IDC versus normal cell types, 78 named genes differentially expressed between normal ductal and lobular cells, and 28 named genes between IDC and ILC. Genes distinguishing between IDC and ILC are involved in epithelial-mesenchymal transition, TGF-beta and Wnt signaling. These changes were present in both tumor types but appeared to be more prominent in ILC. Immunohistochemistry for several novel markers (EMP1, DVL1, DDR1) distinguished large sets of IDC from ILC. CONCLUSION: IDC and ILC can be differentiated both at the gene and protein levels. In this study we report two candidate genes, asporin (ASPN) and collagen triple helix repeat containing 1 (CTHRC1) which might be significant in breast carcinogenesis. Besides E-cadherin, the proteins validated on tissue microarrays (EMP1, DVL1, DDR1) may represent novel immunohistochemical markers helpful in distinguishing between IDC and ILC. Further studies with larger sets of patients are needed to verify the gene expression profiles of various histological types of breast cancer in order to determine molecular subclassifications, prognosis and the optimum treatment strategies

    Revitalizace Ceskych drah v souvislosti s Bilou knihou Evropske unie

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    Dissertation work summarises development of the railway company in Czech Republic in the pre-war period until current state and its economical resultsSummary in EnglishAvailable from STL Prague, CZ / NTK - National Technical LibrarySIGLECZCzech Republi

    Maybe nothing, maybe something

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    In 1965, Jiƙi Koláƙ wrote an article which revealed his creative evolution not only as a poet but also as original artist who especially concentrated on collages. The definition of evident poetry includes the circumstances of the breakup with traditional poetry, in which words carried meaning. Kolazh analyzes the essence of his visual poetry while revealing the mundane inspiration and genesis (literal and figurative). He concentrated on the so-called ‘subject poems’ and earlier gradual discovery of the varieties of collage technique. Imaging characteristics of creative learning through different kinds of collage is based on the idea of overlapping poetry and visual arts. Readers of poetry participate in writing poems based on poetic ‘instruction’. Kolazh’s non-static poetry (also known as ‘comparative texts’) can be compared with action art. At the end of the article, Kolazh analyses the perspective of that kind of literature
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