29,776 research outputs found
Release kinetics of ampicillin, biocompatibility tests with a fibroblast strain of a zirconia gel glass
No full textBiocompatibility remains the central theme for biomaterials applications in medicine. It is generally accepted that this term does not indicate only absence of a cytotoxic effect but also positive effects in the sense of biofunctionality, i.e. promotion of biological processes considering the intended aim of the application of a biomaterial. Biocompatibility of zirconia gel glass was studied using in vitro testing methods, the incubation period was 7, 14, 21 days. The bioactivity of the synthesized material had been shown by the formation of a layer of hydroxyapatite on the surface of ZrO 2-Y2O3(5wt%) samples soaked in a fluid simulating the composition of the human blood plasma (SBF), as observed by SEM and EDS microscopy. Studies of drug delivery kinetics were also carried out. The amount of sodium ampicillin released has been detected by UV-VIS spectroscopy. The released kinetics seems to occur in more than one stage. HPLC analysis had also been carried out to ensure the integrity of ampicillin after the synthetic treatmen
Effects of low power 904 nm radiation on rat fibroblasts explanted and in vitro cultured.
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Darwin : L'arbre de vie
No full textLa teoria dell'evoluzione di Charles Darwin occupa ancora oggi un posto centrale nel dibattito non solo scientifico, ma anche culturale in senso lato. Il concetto di "evoluzione" ricorre infatti con grande frequenza anche nel linguaggio comune, spesso però con significati molto distanti da quello che questo termine ricopre nelle scienze del vivente. Si presenta qui una biografia intellettuale di Darwin che mira a esporne la teoria, ricostruendone il percorso all'interno del contesto storico e socio-politico nel quale essa fu formulata
Waddington tra neo-darwinismo e post-neo-darwinismo
No full textSi analizza la eclettica figura del genetista Konrad Hal Waddington, personaggio chiave, ma “scomodo” della biologia evoluzionistica del Novecento. Nell’ambito della sua teoria, che etichettò come post-neo-darwinismo, si evidenzia l’originalità delle sue posizioni e lo spaccato embriologico-genetico in cui si colloca il suo lavoro teorico e sperimentale, nonché il ricco corredo di neologismi e concetti da lui introdotti (epigenesi, assimilazione genetica, creodo, etc.), con particolare attenzione per la sua insistenza sull’organismo considerato come sistema globale, sui processi morfologici e dello sviluppo, sul ruolo del comportamento e dei fenotipi nell’evoluzione, sottolineandone la attualità per la ricerca più recente in biologia teorica e dello sviluppo
Evaluation by TEM of gastric epithelial cells apoptosis in normal mucosa and in H.pylori related chronic gastritis.
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Histological characterization of Sacco’s concentrated growth factors membrane [Caracterización Histológica de la Membrana de los Factores de Crecimiento Concentrados Sacco]
No full textAlong with the emerging needs of the dental patients, numerous techniques for oral tissue stimulation and regeneration were developed to be employed in the modern implant rehabilitation therapies. The Concentrated Growth Factors (CGF) are a relatively new therapeutic presidium that can be used for this purpose, enhancing the regenerative potential property of blood cells. Although literature presents numerous studies evaluating the CGF for their clinical uses and efficacy, data regarding their biological characteristics are very few. The present study evaluates and describes the CGF structural morphology by means of classical histological methods, using haematoxilin-eosin and azan mallory stains. A three layers organization with a fibrin complex network was noted, with blood corpuscular elements entrapped, especially in the most external layer. These descriptions enrich the knowledge about this new type of membrane, showing the bio-morphological side of the regenerative techniques. These findings will be useful in clinical practice for the choice of the most suitable technique in each implant rehabilitationAlong with the emerging needs of the dental patients, numerous techniques for oral tissue stimulation and regeneration were developed to be employed in the modern implant rehabilitation therapies. The Concentrated Growth Factors (CGF) are a relatively new therapeutic presidium that can be used for this purpose, enhancing the regenerative potential property of blood cells. Although literature presents numerous studies evaluating the CGF for their clinical uses and efficacy, data regarding their biological characteristics are very few. The present study evaluates and describes the CGF structural morphology by means of classical histological methods, using haematoxilin-eosin and azan mallory stains. A three layers organization with a fibrin complex network was noted, with blood corpuscular elements entrapped, especially in the most external layer. These descriptions enrich the knowledge about this new type of membrane, showing the bio-morphological side of the regenerative techniques. These findings will be useful in clinical practice for the choice of the most suitable technique in each implant rehabilitation
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