1,721,022 research outputs found
Degalatosylated xyloglucan hydrogels: influence of irradiation conditions on physico-chemical properties and structure
No full textTemperature-responsive degalactosylated xyloglucans as nanocarriers for the sustained release of hydrophobic drugs
No full textPreparazione di nanoparticelle di xiloglucano degalattosilato per applicazioni biomediche
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Inhibiting effect of αs1-casein on Aβ1–40 fibrillogenesis
No full textBackground: α s1-Casein is one of the four types of caseins, the largest protein component of bovine milk. The lack of a compact folded conformation and the capability to form micelles suggest a relationship of α s1-casein with the class of the intrinsically disordered (or natively unfolded) proteins. These proteins are known to exert a stabilizing activity on biomolecules through specific interaction with hydrophobic surfaces. In the present work we focused on the effect of α s1- casein on the fibrillogenesis of 1-40 β-amyloid peptide, involved in Alzheimer's disease. Methods: The aggregation kinetics of β-peptide in presence and absence of α s1-casein was followed under shear at 37 °C by recording the Thioflavine fluorescence, usually taken as an indicator of fibers formation. Measurements of Static and Dynamic Light Scattering, Circular Dichroism, and AFM imaging were done to reveal the details of α s1-casein-Aβ 1-40 interaction. Results and discussions: α s1-Casein addition sizably increases the lag-time of the nucleation phase and slows down the entire fibrillization process. α s1-Casein sequesters the amyloid peptide on its surface thus exerting a chaperone-like activity by means a colloidal inhibition mechanism. General significance: Insights on the working mechanism of natural chaperones in preventing or controlling the amyloid aggregation
Irreversible gelation of thermally unfolded proteins:structural and mechanical properties of lysozyme aggregates
No full textThe formation of protein aggregates is important in many fields of life science and technology. The morphological and mechanical properties of protein solutions depend upon the molecular conformation and thermodynamic and environmental conditions. Non-native or unfolded proteins may be kinetically trapped into irreversible aggregates and undergo precipitation or gelation. Here, we study the thermal aggregation of lysozyme in neutral solutions. We characterise the irreversible unfolding of lysozyme by differential scanning calorimetry. The structural properties of aggregates and their mechanisms of formation with the eventual gelation are studied at high temperature by spectroscopic, rheological and scattering techniques. The experiments show that irreversible micron-sized aggregates are organised into larger clusters according to a classical mechanism of diffusion and coagulation, which leads to a percolative transition at high concentrations. At a smaller length scale, optical and atomic force microscopy images reveal the existence of compact aggregates, which are the origin of the aggregation irreversibility
Protofibril formation of amyloid beta-protein at low pH via a non-cooperative elongation mechanism.
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