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Integrin αv signaling influences phenotype and maturation of primary human osteoblasts on alumina surface

Wróbel E., Witkowska-Zimny M., Mrówka P., Głodkowska-Mrówka E.

Engineering of Biomaterials

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2014

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Vol. 17, no. 127

33--39

EN

Due to the growing interest in stem cells application in tissue engineering the better understanding of primary human osteoblasts behavior in vitro, on biomaterial surface, is required. Among other molecules integrins may be taken into account as being involved in these phenomena. Integrins are a family of cell adhesion receptors, which may regulate many cellular functions e.g., adhesion, motility, phenotype and cell maturation. The aim of this study was to determine the effect of the biomaterial surfaces and αv integrin signaling pathway on the behavior, phenotype and maturation of human osteoblasts in vitro. Human bone derived cells (HBDCs) obtained from adult femoral bone fragments were cultured on both alumina disks and tissue culture polystyrene (TCPS) dishes. After 7, 14, and 21 days of culture, localization and mRNA expression level of αv integrin subunits and BGLAP (osteocalcin) on polystyrene were analyzed in addition, we treated the cell cultures with monoclonal antibodies against human αv integrin to block its ligand-binding activity, on both alumina and TCPS substrates. We found that the αv integrin was present in focal contacts and cell cytoplasm at subsequent stages of cell maturation and the level of αv integrin mRNA was the highest in mature osteoblasts. Blocking αv integrin transduction pathway caused changes in cell activity and morphology, decreased cells proliferation on TCPS and reduced expression of alkaline phosphatase (ALP) on both materials. The results suggest that αv integrin is involved as an important receptor facilitating osteogenic differentiation.

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Selected aspects of digital image processing applications in ITS

Mrówka P., Olejniczak M.

Archives of Transport System Telematics

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2013

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Vol. 6, iss. 3

23--26

EN

Digital image processing algorithms are commonly applied in Intelligent Transport Systems (ITS). Their effective operation is conditioned on the high robustness to real-life image distortions and the computational complexity suitable for implementation on a non expensive industrial computer. The paper presents three original image analysis methods designed for the ITS, with special attention paid on aforementioned conditions. Colour image parametrization method for the traffic light state classifier was described. The algorithm utilizes CIELAB colour space properties. The method of vehicle edges parametrization for the make and model classifier was presented. The proposed representation relies on thresholded coefficients of gradient magnitude approximation in low dimensional space. The paper presents also the method of image characteristic features detection for the licence plates localization task. The detection is performed by means of appropriately designed filters with low computational complexity.

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Normalization of speaker individual characteristics and compensation of linear transmission distortions in command recognition systems

Mrówka P., Makowski R.

Archives of Acoustics

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2008

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Vol. 33, No. 2

221-242

EN

The article presents a~novel method of speaker individual characteristics normalization and linear transmission distortion compensation aimed at improving the effectiveness of short isolated utterances recognition. To achieve this goal, spectral transformation banks of a~speaker's signal and the division of speakers into classes were applied. The article also discusses the form of spectral transformation, the method of its parameter values optimization, the method of transformation banks definition, the method of speaker classes selection and the way of iterative improvement of recognition results. Moreover, the study puts forward a fast method of speaker classes selection on the basis of the fundamental voice frequency. The efficiency of the proposed solution has been validated by the recognition results obtained by means of four versions of a recognition system using Hidden Markov Models (HMM) and the mel frequency cepstral coefficients (MFCC) parametrization.