Search results for "Solid"
showing 10 items of 3575 documents
Protein Thermal Denaturation and Matrix Glass Transition in Different Protein−Trehalose−Water Systems
2011
Biopreservation by saccharides is a widely studied issue due to its scientific and technological importance; in particular, ternary amorphous protein-saccharide-water systems are extensively exploited to model the characteristics of the in vivo biopreservation process. We present here a differential scanning calorimetry (DSC) study on amorphous trehalose-water systems with embedded different proteins (myoglobin, lysozyme, BSA, hemoglobin), which differ for charge, surface, and volume properties. In our study, the protein/trehalose molar ratio is kept constant at 1/40, while the water/sugar molar ratio is varied between 2 and 300; results are compared with those obtained for binary trehalose…
Nucleation and Growth of CaCO3 Mediated by the Egg-White Protein Ovalbumin: A Time-Resolved in situ Study Using Small-Angle Neutron Scattering
2008
Mineralization of calcium carbonate in aqueous solutions starting from its initiation was studied by time-resolved small-angle neutron scattering (SANS). SANS revealed that homogeneous crystallization of CaCO 3 involves an initial formation of thin plate-shaped nuclei which subsequently reassemble to 3-dimensional particles, first of fractal and finally of compact structure. The presence of the egg-white protein ovalbumin leads to a different progression of mineralization through several stages; the first step represents amorphous CaCO 3, whereas the other phases are crystalline. The formation and dissolution of the amorphous phase is accompanied by Ca (2+)-mediated unfolding and cross-link…
Recent Advances in Affinity MOF-Based Sorbents with Sample Preparation Purposes
2020
This review summarizes the recent advances concerning metal–organic frameworks (MOFs) modified with several biomolecules (e.g., amino acids, nucleobases, proteins, antibodies, aptamers, etc.) as ligands to prepare affinity-based sorbents for application in the sample preparation field. The preparation and incorporation strategies of these MOF-based affinity materials were described. Additionally, the different types of ligands that can be employed for the synthesis of these biocomposites and their application as sorbents for the selective extraction of molecules and clean-up of complex real samples is reported. The most important features of the developed biocomposites will be discussed thr…
Study of Prussian Blue (PB) films by ac-electrogravimetry: influence of PB morphology on ions movement
2000
The electrochemical response of Prussian Blue films in NaCl solutions was studied. It was proved that the stability with cycling of PB films increased when these films are covered with a Nafion® membrane. This fact allows PB films to be studied in NaCl solutions under steady state conditions by impedance spectroscopy and ac-electrogravimetry. A model, which can explain the differences between the electrochemical behaviour of amorphous PB films and crystalline PB films in NaCl solutions, is proposed. This model is based on the hypothesis of a partial dehydration of the sodium ions before the electrochemical reactions take place, allowing the transport of sodium ions through the zeolitic chan…
MOKE magnetometry as a probe of surface magnetic impurities in electropolymerized magnetic thin films of the Prussian blue analogue Fe3[Cr(CN)6]2·15 …
2013
A magneto-optical Kerr effect (MOKE) study has been performed on electrodeposited thin films of the Prussian blue analogue Fe3[Cr(CN)6]2·15H2O (1). This study reveals the onset of hysteretic magnetic signals at temperatures above 60 K, in contrast with magnetic susceptibility measurements which indicate a Curie temperature of 23 K for this ferromagnetic film. The origin of this discrepancy is due to the presence of amorphous iron oxide particles that accumulate in the surface of the material. This report illustrates the potential of MOKE magnetometry for the detection of surface chemical impurities that remain elusive using bulk magnetic techniques.
Theoretical study of the stabilization of cubic-phaseZrO2by impurities
1994
We have performed a thermodynamical analysis of the phase diagrams for ${\mathrm{ZrO}}_{2}$-CaO and ${\mathrm{ZrO}}_{2}$-MgO solid solutions which has demonstrated that differential heats of mixing are important parameters determining the stabilization of the cubic phase of ${\mathrm{ZrO}}_{2}$ by impurities. It is shown that the differential heats of mixing in the cubic phase of these systems should be lower than in the tetragonal phase. To understand this effect we have studied the electronic and geometrical structures of the pure and doped ${\mathrm{ZrO}}_{2}$ crystals. Three computational techniques were employed: the ab initio Hartree-Fock pseudopotential method is used to study the at…
Informal Learning for Citizenship Building in Shared Struggles for Right: Cases of Political Solidarity Between Colombian and Spanish Organisations
2015
[EN]: Dominant discourses and practices in international cooperation have been characterised by depoliticisation and unequal power relationships. However, a number of more transformative experiences of cooperation also exist, where joint work between Northern and Southern social organisations is linked with a more political perspective. These kinds of experiences can be considered processes of informal learning in social action: through shared actions, strategies and frameworks and through interaction between organisations, institutions and the grassroots, informal and multidimensional learning processes occur in the people and organisations engaged. The study approaches four cases of netwo…
Amministrazione performante e sistema dei controlli interni
2023
Since the origins of post-unitary reform processes, analyses, and reconstructions aimed at deepening the needs and development paths for maximizing the functioning of the italian administration have directly or indirectly included the legal institutions of administrative control. Controls have progressively become an essential thematic axis in the characterization of the fundamental contents of the formation of the administrative state and the 'administrative question' of conformity in public organization and administrative activity to the principle of legality. They are seen as a specific legal institution, in which it is possible to interpret both the evolution of the state organization a…
The ‘value of solidarity’ in the public housing stock alienation. a case study in palermo (italy)
2020
As many low-income households have still been facing the problem of affordable housing, in several countries governmental institutions have implemented various measures of housing policy and are supporting both the “right to housing” and the “right to buy” a dwelling at a subsidized price. Alienation of public housing is a political measure mostly directed towards low-income tenants, by which the dwellings are sold at a price set by law, assumed as a “administered” price. The gap between market and administered prices may be considered as the “value of solidarity” to be taken into account as the monetary reference of the social housing welfare policies aimed at reducing social inequities. T…
Efficiency versus Fairness in the Management of Public Housing Assets in Palermo (Italy)
2019
Public housing policy has been proposing plans of public housing (PH) stock alienation or, as an alternative, property enhancement plans, since administrative and financial commitments have become too heavy for municipalities. This paper deals with one of the current public housing management policy initiatives, undertaken by the Municipality of Palermo (Italy), which aimed at transferring a significant part of the public housing asset to the current tenants, according to some terms and conditions, and applying a politically fixed price. This policy is described in general, focusing on the amount of the assets involved, reporting the terms and conditions for transferring them at an affordab…