Untersuchungen zur kardialen Differenzierung adulter Stammzellen und Entwicklung lentiviraler Vektoren zur spezifischen Detektion und Aufreinigung von Kardiomyozyten

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The use of homomorphic image processing to analyze coke grading

The estimation of the geometrical sizes of particles of crushed solid fuel (coke), moving on the conveyor belt, is associated with a number of technical difficulties. One of the problems is the need for a non-invasive way of determining particle geometry. A promising way to solve it is to use devices based on machine vision systems. This paper describes the algorithmic part of the prototype of such a device. It is proposed to improve the quality of boundary detection between fragments of coke particles to perform homomorphic processing of the initial low-contrast video images. The algorithm for calculating the Fourier spectrum has been optimized based on the Fast Fourier Transform (FFT) with the mixed base. As a result, it becomes possible to reduce the computational cost for calculating two-dimensional Fourier spectra for complex multiplication operations by 1.33 times, and the number of complex addition operations by 1.67 times. The software of the prototype, built using the proposed methods, made it possible to obtain good convergence of the results for assessing the particle size distribution of samples of crushed coke with laboratory estimates. Thus, the maximum absolute average error of the machine vision system in assessing the size of crushed coke is only 3.37%, and the maximum error for all measurement classes do not exceed 6.9%. © Published under licence by IOP Publishing Ltd

Higher frequencies of BCRP+ cardiac resident cells in ischaemic human myocardium

Aims Several cardiac resident progenitor cell types have been reported for the adult mammalian heart. Here we characterize their frequencies and distribution pattern in non-ischaemic human myocardial tissue and after ischaemic events. Methods and results We obtained 55 biopsy samples from human atria and ventricles and used immunohistological analysis to investigate two cardiac cell types, characterized by the expression of breast cancer resistance protein (BCRP)/ABCG2 [for side population (SP) cells] or c-kit. Highest frequencies of BCRP+ cells were detected in the ischaemic right atria with a median of 5.40% (range: 2.48-11.1%) vs. 4.40% (1.79-7.75%) in the non-ischaemic right atria (P = 0.47). Significantly higher amounts were identified in ischaemic compared with non-ischaemic ventricles, viz. 5.44% (3.24-9.30%) vs. 0.74% (0-5.23%) (P = 0.016). Few numbers of BCRP+ cells co-expressed the cardiac markers titin, sarcomeric α-actinin, or Nkx2.5; no co-expression of BCRP and progenitor cell marker Sca-1 or pluripotency markers Oct-3/4, SSEA-3, and SSEA-4 was detected. C-kit+ cells displayed higher frequencies in ischaemic (ratio: 1:25 000 ± 2500 of cell counts) vs. non-ischaemic myocardium (1:105 000 ± 43 000). Breast cancer resistance protein+/c-kit+ cells were not identified. Following in vitro differentiation, BCRP+ cells isolated from human heart biopsy samples (n = 6) showed expression of cardiac troponin T and α-myosin heavy-chain, but no full differentiation into functional beating cardiomyocytes was observed. Conclusion We were able to demonstrate that BCRP+/CD31− cells are more abundant in the heart than their c-kit+ counterparts. In the non-ischaemic hearts, they are preferentially located in the atria. Following ischaemia, their numbers are elevated significantly. Our data might provide a valuable snapshot at potential progenitor cells after acute ischaemia in vivo, and mapping of these easily accessible cells may influence future cell therapeutic strategie

A micro-LED array based platform for spatio-temporal optogenetic control of various cardiac models

Optogenetics relies on dynamic spatial and temporal control of light to address emerging fundamental and therapeutic questions in cardiac research. In this work, a compact micro-LED array, consisting of 16 × 16 pixels, is incorporated in a widefield fluorescence microscope for controlled light stimulation. We describe the optical design of the system that allows the micro-LED array to fully cover the field of view regardless of the imaging objective used. Various multicellular cardiac models are used in the experiments such as channelrhodopsin-2 expressing aggregates of cardiomyocytes, termed cardiac bodies, and bioartificial cardiac tissues derived from human induced pluripotent stem cells. The pacing efficiencies of the cardiac bodies and bioartificial cardiac tissues were characterized as a function of illumination time, number of switched-on pixels and frequency of stimulation. To demonstrate dynamic stimulation, steering of calcium waves in HL-1 cell monolayer expressing channelrhodopsin-2 was performed by applying different configurations of patterned light. This work shows that micro-LED arrays are powerful light sources for optogenetic control of contraction and calcium waves in cardiac monolayers, multicellular bodies as well as three-dimensional artificial cardiac tissues

Murine and human pluripotent stem cell-derived cardiac bodies form contractile myocardial tissue in vitro

AimsWe explored the use of highly purified murine and human pluripotent stem cell (PSC)-derived cardiomyocytes (CMs) to generate functional bioartificial cardiac tissue (BCT) and investigated the role of fibroblasts, ascorbic acid (AA), and mechanical stimuli on tissue formation, maturation, and functionality.Methods and resultsMurine and human embryonic/induced PSC-derived CMs were genetically enriched to generate three-dimensional CM aggregates, termed cardiac bodies (CBs). Addressing the critical limitation of major CM loss after single-cell dissociation, non-dissociated CBs were used for BCT generation, which resulted in a structurally and functionally homogenous syncytium. Continuous in situ characterization of BCTs, for 21 days, revealed that three critical factors cooperatively improve BCT formation and function: both (i) addition of fibroblasts and (ii) ascorbic acid supplementation support extracellular matrix remodelling and CB fusion, and (iii) increasing static stretch supports sarcomere alignment and CM coupling. All factors together considerably enhanced the contractility of murine and human BCTs, leading to a so far unparalleled active tension of 4.4 mN/mm2 in human BCTs using optimized conditions. Finally, advanced protocols were implemented for the generation of human PSC-derived cardiac tissue using a defined animal-free matrix composition.ConclusionBCT with contractile forces comparable with native myocardium can be generated from enriched, PSC-derived CMs, based on a novel concept of tissue formation from non-dissociated cardiac cell aggregates. In combination with the successful generation of tissue using a defined animal-free matrix, this represents a major step towards clinical applicability of stem cell-based heart tissue for myocardial repair. © 2013 The Author

Instructor's manual to accompany understanding American government

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LED Projector of Pulse Backlight for Machine Vision System

The paper presents technical description of pulse LED backlight. This system is implemented in machine vision systems designed for high-speed processes control. Pulse projectors managed on the basis of starting time and duration of the pulse. The system provides control of electrical parameters of projectors, such as input voltage and current of the LED array, which are measured during backlight pulse operate time. This information gives an indirect measurement of the LED arrays' state. The design of the system and implementation example are given. © Published under licence by IOP Publishing Ltd.Incheon Disaster Prevention Research Center (IDPRC);Incheon National Universit