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Stain exclusion band pattern of native type I collagen fibrils. The involvement of chain amino acid hydrophobicity
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Collagen-glutaraldehyde interaction as revealed by the D-banding of negatively stained fibrils and computer drawn band patterns
No full textNegative staining and genesis of D-periodicity in native collagen fibrils
No full textAn investigation was carried out on the mechanism which gives rise to the banding exhibited by collagen fibrils after negative staining. The negative staining (phosphotungstic acid) band patterns of native collagen fibrils (type I), isolated from calf reticular dermis, were compared with computer-drawn band patterns. The stimulations were based on the primary structure of bovine type I collagen, the "quarter stagger" molecular packing and different conformations of telopeptides. The results suggest that in negative staining, the stain exclusion effect depends on both spatial factors and water repelling factors being the "bulkiness" (molecular volume/length ratio) as well as the hydrophobicity of the amino acids of alpha 1 (I) and alpha 2 (I) chains directly involved. No final conclusion could be drawn about the contribution of positive staining to negative staining. Improvements in the simulations were achieved when the telopeptides were shaped according to particular conformational models
Sulla esistenza di sovrapposizione fra colorazione negativa e colorazione positiva nella fibrilla collagena
No full textStructural Aspects of the Extracellular Matrix of Tendon: An Atomic Force and Scanning Electron Microscopy Study
No full textAl limite...potrei giocare così
No full textQuesto articolo è il prodotto finale di una serie di studi ed esperienze svolte nell’ambito accademico e riguardanti le discipline di Didattica della Matematica2 frequentati negli a.a. 2008/2010.
Tale lavoro è centrato sul concetto di limite di una funzione, limite di una successione e su un particolare
limite notevole. Abbiamo preferito trattare il concetto di limite perché crediamo che tale concetto stia alla
base dell’analisi matematica e che nella sua interpretazione presenti agli studenti non poche difficoltà di tipo concettuale.
Nell’articolo per sottolineare questo aspetto, abbiamo analizzato, seppur in una prima approssimazione,
il percorso storico-epistemologico dello stesso concetto.
Dal punto di vista didattico abbiamo poi proposto questo argomento in maniera diversa dagli schemi usuali e quindi con un contatto più diretto e meno astratto che potesse maggiormente stimolare l’interesse di studenti di scuola Secondaria Superiore e favorirne una più facile comprensione.
Una prima fase del nostro lavoro riguarda lo studio delle strategie risolutive adottate dagli studenti, una
volta che fosse stato loro presentato un problema. La seconda parte nasce come prosecuzione e perfezionamento della prima, prendendo in esame una situazione a-didattica in modo da renderla realizzabile praticamente.This article is the final work of a series of studies and experiences done in the academic background and concerning the subjects of Mathematics Teaching2
attended in the years 2008/2010.
This work is focused on the concept of limit of a function, limit of a succession and on a particular remarkable limit. We preferred treating the concept of limit because we guess it lays on the basis of mathematics analysis and that, in its interpretation, it causes not few difficulties to students.
In the article, in order to underline this aspect, we have analyzed, even if as a first approximation, the historical-epistemological line of the concept of limit.
From the didactical point of view, we proposed this topic in a different way from usual schemes; than in a
straighter and less abstract way, able to stimulate as much as possible the interest of the students attending
High School and promote an easier comprehension.
The first phase of our work concerns the study of resolution strategies used by the students, once a problem had been introduced to them. The second part was born as a prosecution and amelioration of the first one, focused on an a a-didactical situation in order to make it practically realizable
Evidences of hydroxyproline-glutaraldehyde interaction during fixation of native collagen fibrils
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