Search results for "SCAFFOLD"
showing 10 items of 470 documents
Chromatin Domains and Regulation of Transcription
2007
Compartmentalization and compaction of DNA in the nucleus is the characteristic feature of eukaryotic cells. A fully extended DNA molecule has to be compacted 100,000 times to fit within the nucleus. At the same time it is critical that various DNA regions remain accessible for interaction with regulatory factors and transcription/replication factories. This puzzle is solved at the level of DNA packaging in chromatin that occurs in several steps: rolling of DNA onto nucleosomes, compaction of nucleosome fiber with formation of the so-called 30 nm fiber, and folding of the latter into the giant (50-200 kbp) loops, fixed onto the protein skeleton, the nuclear matrix. The general assumption is…
Polyphosphate, the physiological metabolic fuel for corneal cells: a potential biomaterial for ocular surface repair
2019
The regeneration of the epithelium, covering the avascular cornea, involves the processes of differentiation, proliferation and migration of cells originating from the corneal epithelial stem cells. We ask the question if these energy-consuming processes can be fueled by the physiological, inorganic polyphosphate (polyP), the main energy storage/donor molecule in the extracellular space. The ex vivo results reveal that addition of polyP, in the form of soluble Na-polyP, to the culture medium elicits a strong stimulatory effect on cell viability/growth and migration of corneal epithelial cells. Microscopic analyses of partially denuded cornea specimens show that in the presence of polyP, but…
Dynamic processes involved in the pre-vascularization of silk fibroin constructs for bone regeneration using outgrowth endothelial cells
2009
For successful bone regeneration tissue engineered bone constructs combining both aspects, namely a high osteogenic potential and a rapid connection to the vascular network are needed. In this study we assessed the formation of pre-vascular structures by human outgrowth endothelial cells (OEC) from progenitors in the peripheral blood and the osteogenic differentiation of primary human osteoblasts (pOB) on micrometric silk fibroin scaffolds. The rational was to gain more insight into the dynamic processes involved in the differentiation and functionality of both cell types depending on culture time in vitro. Vascular tube formation by OEC was assessed quantitatively at one and 4 weeks of cul…
Effect of bioglass on growth and biomineralization of SaOS-2 cells in hydrogel after 3D cell bioprinting.
2014
We investigated the effect of bioglass (bioactive glass) on growth and mineralization of bone-related SaOS-2 cells, encapsulated into a printable and biodegradable alginate/gelatine hydrogel. The hydrogel was supplemented either with polyphosphate (polyP), administered as polyP • Ca2+-complex, or silica, or as biosilica that had been enzymatically prepared from ortho-silicate by silicatein. These hydrogels, together with SaOS-2 cells, were bioprinted to computer-designed scaffolds. The results revealed that bioglass (nano)particles, with a size of 55 nm and a molar ratio of SiO2 : CaO : P2O5 of 55 : 40 : 5, did not affect the growth of the encapsulated cells. If silica, biosilica, or polyP …
Carboxylated-xyloglucan and peptide amphiphile co-assembly in wound healing.
2021
Abstract Hydrogel wound dressings can play critical roles in wound healing protecting the wound from trauma or contamination and providing an ideal environment to support the growth of endogenous cells and promote wound closure. This work presents a self-assembling hydrogel dressing that can assist the wound repair process mimicking the hierarchical structure of skin extracellular matrix. To this aim, the co-assembly behaviour of a carboxylated variant of xyloglucan (CXG) with a peptide amphiphile (PA-H3) has been investigated to generate hierarchical constructs with tuneable molecular composition, structure, and properties. Transmission electron microscopy and circular dichroism at a low c…
What can the concept of affective scaffolding do for us?
2020
The concept of affective scaffolding designates the various ways in which we manipulate the environment to influence our affective lives. In this article, I present a constructive critique of recent discussion on affective scaffolding. In Part 1, I summarize how the theories of situated mind and niche construction contribute to a multidimensional notion of scaffolding. In Part 2, I focus specifically on affective scaffolding and argue that current ambiguity over its distinctive criteria causes uncertainty as to how the concept can and should be used. In Part 3, I identify and examine two possible responses to the suggested state of conceptual ambiguity. The first, restrictive option is to k…
Full‐thickness tissue engineered oral mucosa for genitourinary reconstruction: A comparison of different collagen‐based biodegradable membranes
2020
Tissue engineering is a method of growing importance regarding clinical application in the genitourinary region. One of the key factors in successfully development of an artificially tissue engineered mucosa equivalent (TEOM) is the optimal choice of the scaffold. Collagen scaffolds are regarded as gold standard in dermal tissue reconstruction. Four distinct collagen scaffolds were evaluated for the ability to support the development of an organotypical tissue architecture. TEOMs were established by seeding cocultures of primary oral epithelial cells and fibroblasts on four distinct collagen membranes. Cell viability was assessed by MTT-assay. The 3D architecture and functionality of the ti…
Using Taguchi method for the optimization of processing variables to prepare porous scaffolds by combined melt mixing/particulate leaching
2017
Synthetic biopolymers have made significant inroads into the development of devices for tissue regeneration. In this context, a challenge is the achievement of appropriate properties mimicking the natural extracellular matrix by fabricating scaffolds presenting mechanical properties, specific surface, porosity and pore interconnection adequate for the final application. This study involved a systematic procedure based on Taguchi method for parameters optimization of melt mixing/particulate leaching combined processes aiming to enhance the performance of the scaffolds. In particular, it was evaluated the effect of time and temperature of melt mixing of the poly(lactic acid) matrix with two w…
Writting practice for developp mind and language
2016
This thesis wanted to put on the opposite between established culture, transmitted by School, and private culture, the VAE candidates’ concerned by this research, as well as the author’s. This putting on the opposite is fed by a purpose: to show to what extent the individual and collective work of writing on practical, allows to articulate first the peculiarity of the subjects, the trajectories, the experiences, the situations and the activities, with the generalization of the institutional speech linked with the standardized procedures of the device VAE ? In a second time does this work of writing allows to build knowledges from the experience, object and source of development, and to make…
Suomen kielen oppimisen mahdollisuudet ja työyhteisön tuki puhdistuspalvelualalla: afrikkalaisten maahanmuuttajien käsityksiä ja kokemuksia
2013
This article presents a triple case study of African immigrants’ beliefs about Finnish language learning and support of the work community in the cleaning industry. Cleaning does not require a high language proficiency and it is therefore a typical first job for immigrants, a so-called entrance job. The theoretical framework of the study combines dialogical and sociocultural perspectives on language learning. Learners’ beliefs about work-related affordances and scaffolding are analysed using a dialogical analysis of beliefs. The interviewees’ shared belief is that in spite of their simple duties, cleaning work does provide affordances for learning, e.g. in the form of work-related announcem…