751 research outputs found
Introducing controllable 3D features into dense collagen constructs for tissue engineering applications
Plastic compression of collagen is based on unidirectional expulsion of fluid
from hydrated collagen gel. The process results in dense collagen sheet, with higher
density of collagen at the fluid leaving surface (FLS) than non-FLS. Compression
process is completely cell-independent and at the same time cell-friendly. However,
engineered tissues should replicate not only components of tissues in vivo
(extracellular matrix and cells) but also their complex micro-architecture. Therefore
the aim of this work was to develop collagen-based scaffolds with controllable micro-architecture
for biomedical and tissue engineering applications using plastic
compression (PC) of collagen. The objectives of this project were: i. to test formation
of progressively opening channels in the PC collagen, ii. to investigate stable and
predictable PC collagen patterning, iii. to adapt PC method in a upward-flow system
as a route to process automation, iv. to investigate formation of channels using in
layered PC collagen constructs. Two approaches were used in this work.
Firstly, internal channels were introduced using lost fibre approach, where
soluble glass fibres are incorporated in the scaffold and leave channel when dissolved.
Shape and potentially progression of the channels’ opening is controlled by the shape
of the template. The shape of the fibres was altered from cylindrical to conical in a
controlled manner and incorporated into the PC constructs, resulting in conically-shaped
channels, giving predictable internal 3D structures.
The second approach relied on formation of dense collagen zone at the fluid
leaving surface of the compressed collagen constructs. Formation of the densely
packed collagen zone at the fluid leaving surface is essential for stable and faithful
pattern formation in the process of micro-moulding. This finding has been applied in a
novel upward-flow compression system to create channels using a ‘roofing’
technique. ‘Roof’ is formed by a compression of a new collagen gel on top of a
patterned one; process results in open lumen channels. This appears to be due to a
combination of the small dimension of the grooves in the base layer and viscosity of
the collagen in the upper layer.
This work demonstrates a new, previously unknown level of subtlety by which
collagen fibrils can be packed and aggregated due to directional fluid flow. The
outcome of this work is important for understanding pattern formation in PC collagen
in vitro and potentially tissue morphogenesis in vivo. It also introduces new
generation of implantable living tissue equivalents with complex micro-architecture.
The multi-well compression technique has already been implemented in semi-automative
working station for biomedical applications
The Influence of Socio-Economic Situation in the Regions of the North Caucasus Federal District of the Russian Federation on The Sources of Terrorist Crimes
It was found that over the past 5 years a number of crimes of a terrorist nature has greatly increased. The hypothesis appeared that the adverse socio-economic situation creates conditions for the growth of crimes of a terrorist nature. As a result, the analysis revealed an inverse relationship between the "actual final consumption per person in thousand rubles ", average cash income per month in thousand rubles and the number of crimes of a terrorist nature. Keywords: socio-economic development, crimes of a terrorist nature, region, North-Wes
Introducing stable microgrooves in to fluid-leaving surface of plastic compressed collagen by embossing
Micropatterning of polymers is a technique used in tissue engineering to create additional features on the surface usually to manipulate cell behaviour. However, methods used for fabrication of such features on the surface of synthetic polymers are not always suitable for natural polymers. Here we describe a method of embossing developed for plastic compressed collagen constructs. Plastic compression (PC) of collagen is a technique that allows cell-independent fabrication of dense, tissue-like collagen constructs without compromising viability of resident cells (1). Method of PC creates potential anisotropy of the opposite surfaces – stiffer fluid leaving (closest to the blotting elements) and more elastic non-fluid leaving surface. We hypothesized that embossing into these surfaces will give more stable features on the fluid-leaving surface (FLS) as opposed to non fluid-leaving surface (NFLS). Objectives were to develop methods of embossing onto both surfaces, assess these features and to determine stability of the embossed pattern over time with and without cells. Slow-dissolving phosphate-based glass fibers were used as the embossing template in this study as fiber diameter and spacing is easily controlled
Quantitative reconstruction of holocene climate changes by mineralogical analysis of palaeosols in the steppe regions of East europe
ASSESSING THE LEVEL OF INFORMATIZATION CONTROL AND SUPERVISORY AUTHORITIES OF THE RUSSIAN FEDERATION AND THE PROSPECTS FOR DEVELOPMENT IN THIS DIRECTION
The authors estimate the level of informatization control and supervisory authorities of the Russian Federation, analyze the problems and complexities of the introduction of electronic technologies in the process of governance. Are identified areas introduction of information technologies in the management of the state, considered the problem of informatization of public authorities. The authors provide recommendations for informatization that improve the efficiency of the control and supervision of public authorities
ASSESSING THE LEVEL OF INFORMATIZATION CONTROL AND SUPERVISORY AUTHORITIES OF THE RUSSIAN FEDERATION AND THE PROSPECTS FOR DEVELOPMENT IN THIS DIRECTION
The authors estimate the level of informatization control and supervisory authorities of the Russian Federation, analyze the problems and complexities of the introduction of electronic technologies in the process of governance. Are identified areas introduction of information technologies in the management of the state, considered the problem of informatization of public authorities. The authors provide recommendations for informatization that improve the efficiency of the control and supervision of public authorities
Russia's anti-offshore policy in the global economic system
© 2014, Mediterranean Center of Social and Educational Research. All rights reserved. Role of offshores in the global economy is rather controversial. It depends on effectiveness of national policy. In whole, offshores have started playing a critical part in global capital and assets flow. In the estimation of specialists, in 1990-s offshores have controlled nearly 20% of total world wealth, and almost 22% of external bank assets have been placed there. Today up to 60% of world money are located in offshore zones, nearly half of financial transactions passes through these zones. World experience has shown that offshore capital is not going to disappear in the foreseeable future. It will undergo essential transformation, growing more transparent and predictable. Yet tax competition and investment potential of certain jurisdictions will keep on determining capital flow in the world economy. Under WTO conditions the authors' suggestions to develop free and special economic zones, using the world experience, will allow Russia to develop regional social infrastructure, to attract investments, including foreign investments, into national economy
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