Social innovation between necessity and opportunity

The contribution of social innovation to the institutional change has been studied in the case of promoting healthy ageing. While major institutional change is well memorized by the present generation, the iterative approach to social innovation build up, and reaching the critical mass for a leap is viewed in the context of a specific region and social group. Selected types of social innovations are projected in their impact on societal challenges and institutional transformation potential

Kirurgija. Interna medicina. Medicinas bazes zinatnes. Stomatologija. Farmacija 2001. gada medicinas nozares petnieciska darba publikacijas

Abstracts in EnglishAvailable from Latvian Academic Library / LAL - Latvian Academic LibrarySIGLELVLatvi

Tannic acid mimicking dendrimers as small intestine submucosa stabilizing nanomordants

Chemical stabilization resulting in increased resistance to proteolytic degradation is one of the approaches in prevention of post-implantational aneurysm development in decellularized natural vascular scaffolds. Recently, tannic acid (TA) and tannic acid mimicking dendrimers (TAMD) have been suggested as potential stabilization agents for collagen and elastin. The aim of this work was to determine the stabilizing effects of TAMD on decellularized natural scaffolds. Vascular scaffolds fabricated from small intestine submucosa (SIS) and SIS plane sheets (Cook Biotech Inc.) were used. The biomechanical properties of the SIS vascular graft segments treated with TA and TAMD were tested. The effect of TAMD treatment on resistance to proteolytic degradation was evaluated by measuring biomechanical properties of TAMD stabilized and non-stabilized SIS specimens after incubation in collagenase solution. It was shown that treatment with TA as well as with TAMD increased the strength of tubular SIS as well as their resistance to proteolytic biodegradation manifested by preservation of biomechanical properties after collagenase treatment. Transmission electron microscopy demonstrated that treatment with TAMD increased the periodical pattern typical of collagen fiber ultrastructure as a result of the “mordant” effect. The possible collagen cross-linking effect of TAMD on SIS was investigated by differential scanning calorimetry (DSC). The treatment with TAMD induced a small, but detectable cross-linking effect, suggesting that TAMD do not establish extensive covalent cross links within the extracellular matrix but rather interact with collagen, thus rendering SIS scaffolds more resistant to proteolytic degradation

Structural Determinants of Material Properties of Heart Valve

Structural determinants of material properties of heart valv