Search results for "reserva"
showing 10 items of 630 documents
The Influence of Cultivation Conditions on the Proliferation and Differentiation of Rat Bone Marrow Multipotent Mesenchymal Stromal Cells
2008
Rat bone marrow multipotent mesenchymal stromal cells (rBM MMSCs) demonstrate a potential to differentiate down the mesodermal pathway but under appropriate experimental condition differentiation into non-mesodermal lineages may occur. Knowing this fact it seems interesting whether prolonged cultivation and preservation affects BM MMSC morphology, differentiation ability into multiple lineages and proliferation capacity. Therefore this study was aimed to investigate the effects of long-term cultivation and cryopreservation on the morphology, proliferation and differentiation potential of rat bone marrow-derived MMSCs in vitro.
Annihilation Operators for Exponential Spaces in Subdivision
2022
We investigate properties of differential and difference operators annihilating certain finite-dimensional subspaces of exponential functions in two variables that are connected to the representation of real-valued trigonometric and hyperbolic functions. Although exponential functions appear in a variety of contexts, the motivation behind this work comes from considering subdivision schemes with the capability of preserving those exponential functions required for an exact description of surfaces parametrized in terms of trigonometric and hyperbolic functions.
Cryopreservation of Digitalis obscura selected genotypes by encapsulation-dehydration
2001
Shoot-tips from several genotypes of the cardenolide-producing perennial shrub Digitalis obscura L. were successfully cryopreserved using the encapsulation-dehydration technique. Precultivation on MS medium containing 0.5 M sucrose, followed by 2.5 h dehydration (final weight 30 %) induced shoot regrowth in 42 % of cryopreserved shoot-tips. Cold-hardening of the in vitro cultures before sucrose treatment dramatically increased shoot recovery up to 86 %. The optimized cryopreservation protocol was then employed using different shoot cultures from five D. obscura genotypes. Responses to cryopreservation depended mainly on the genotype, best results being obtained when shoot tips from HU3 and …
Freezing without surrounding cryomedium preserves the endothelium and its function in human internal mammary arteries
2005
Abstract Purpose Cryopreserved human blood vessels may become important tools in bypass surgery. Optimal cryopreservation of an arterial graft should, therefore, preserve both histological and physiological characteristics of smooth muscle and endothelium comparable to the unfrozen artery. Methods Rings from human internal mammary arteries (IMA) were investigated in vitro either unfrozen or after immersion into a cryomedium (RPMI 1640 containing 1.8 M Me2SO and 0.1 M sucrose) and cryostorage with and without surrounding medium. Results In unfrozen IMA, neither contractile responses to noradrenaline (NA) nor endothelium-dependent relaxant responses to acetylcholine (ACH) was modified after e…
Effects of an innovative dipping treatment on the cold storage of minimally processed Annurca apples
2007
The effect of trehalose as an edible coating on minimally processed Annurca apple slices was studied during cold storage. The edible coating was prepared by dipping the fruit in a solution containing trehalose at 0.8%, sucrose at 1.0% and sodium chloride at 0.1%. During storage at 6 degrees C the following parameters were monitored: weight loss, colour (hue angle (h degrees) and whitening index (WI)), firmness, malic and ascorbic acids, polyphenol content.. microstructure by scanning electron microscopy (SEM) and microbial count. The results showed that such a coating reduced the browning phenomena; in fact the WI and h degrees values were significantly lower in coated samples than untreate…
Cryopreservation of white mulberry (Morus alba L.) by encapsulation-dehydration and vitrification
2011
Shoot apices of in vitro-grown plantlets of white mulberry, Morus alba L. cv Florio, were cryopreserved using either encapsulation-dehydration or vitrification. For encapsulation-dehydration, alginate beads containing apices were dehydrated for 1, 3, 5 or 7 days in a liquid medium containing various sucrose concentrations (0.5, 0.75, 1.0 or 1.25 M). Bead desiccation was performed using silica gel for either 0, 4, 6, 8, 9 or 14 h. For vitrification, apices were directly immersed for either 5, 15, 30 or 60 min in a vitrification solution (PVS2). Following encapsulation-dehydration, treatment of alginate beads with 0.75 M sucrose was more effective in promoting re-growth of explants after imme…
“Water Association” Band in Saccharide Amorphous Matrices: Role of Residual Water on Bioprotection
2021
Saccharides protect biostructures against adverse environmental conditions mainly by preventing large scale motions leading to unfolding. The efficiency of this molecular mechanism, which is higher in trehalose with respect to other sugars, strongly depends on hydration and sugar/protein ratio. Here we report an Infrared Spectroscopy study on dry amorphous matrices of the disaccharides trehalose, maltose, sucrose and lactose, and the trisaccharide raffinose. Samples with and without embedded protein (Myoglobin) are investigated at different sugar/protein ratios, and compared. To inspect matrix properties we analyse the Water Association Band (WAB), and carefully decompose it into sub-bands,…
In vitro skin penetration of bronidox, bronopol and formaldehyde from cosmetics
2020
The objective was to evaluate the influence of the formulation in the in vitro transdermal absorption through pig ear skin of three preservatives, bronopol, bronidox and formaldehyde as well as the absorption of formaldehyde from bronopol and dimethyloldimethyl hydantoin (DMDM hydantoin). An aqueous solution, an O/W emulsion and a hydrogel were assayed. Bronidox and bronopol absorption depends on the formulation. The O/W emulsion was the system that least promoted absorption of bronidox while the absorption of bronopol was lower from the hydrogel. The aqueous solution provided maximal transdermal absorption of both preservatives. Moreover, the transdermal absorption of formaldehyde released…
Digital preservation in institutional repositories: a systematic literature review
2021
Purpose This paper aims to carry out a literature review on the implementation of digital preservation policies, strategies and actions by institutional repositories. The objective is to identify, out of the published experiences, at which level they are fulfilling the function of ensuring the long-term availability of the deposited materials. Design/methodology/approach Using a systematic literature review methodology, a total of 21 articles from international refereed journals published between 2009 and 2020 are reviewed. Findings The research production on this subject is very limited. The scarce number of published articles proves that the interest of repository managers has been focus…
Studio dell’apoptosi in oociti umani.
2017
Gli obiettivi delle ricerche condotte sono stati duplici: 1) verificare l’eventuale comparsa o aumento di fenomeni apoptotici nelle cellule follicolari, negli oociti e nelle strutture stromali, di tessuto ovarico sottoposto a criopreservazione. 2) verificare la presenza di apoptosi in oociti non fecondati dopo trattamento ICSI (Intra Citoplasmic Sperm Injection), per comprendere se pregressi eventi apoptotici siano già in atto in oociti umani trattati con tecniche avanzate di fecondazione assistita, e possano pertanto essere la causa della mancata fecondazione di circa il 30-35 % degli oociti trattati.