1,721,023 research outputs found
Relating the rate of growth of metal nanoparticles to cluster size distribution in electroless deposition
No full textElectroless deposition on patterned silicon substrates enables the formation of metal nanomaterials with tight control over their size and shape. In the technique, metal ions are transported by diffusion from a solution to the active sites of an autocatalytic substrate where they are reduced as metals upon contact. Here, using diffusion limited aggregation models and numerical simulations, we derived relationships that correlate the cluster size distribution to the total mass of deposited particles. We found that the ratio ξ between the rates of growth of two different metals [Image: see text] depends on the ratio γ between the rates of growth of clusters formed by those metals [Image: see text] through the linearity law ξ = 14(γ − 1). We then validated the model using experiments. Different from other methods, the model derives k using as input the geometry of metal nanoparticle clusters, decoded by SEM or AFM images of samples, and a known reference
Transport Properties of EVAI-Starch-Alpha Amylase Membranes
No full textWe investigated the influence of various physicochemical parameters on the morphology and time-porosity formation of membranes composed of ethylene-vinyl alcohol, starch and alpha-amylase. In particular, we determined that 1) it is possible to obtain a membrane with desired porosity by phase inversion in an appropriate water-ethanol mixture; 2) the enzymatic bioerosion is controlled by the amount of alpha-amylase present in the blend. Although no experiments involving drugs were carried on, the delivery properties of the film were determined by measuring the Darcy permeability, the effective diffusivity and the mean reaction rate of the membranes, relating them to the modality of membrane preparation, the amount of enzyme present within the membrane and the incubation time of the samples in a buffer solution. Simple theoretical models of the delivery properties of the membranes were developed, leading to predictions that were in good agreement with the experimental results
Surface modification of poly(ethylene-co-vinyl alcohol) membranes by molecular imprinting technique for biomedical application
No full textThe five Ws (and one H) of super-hydrophobic surfaces in medicine
Full text linkSuper-hydrophobic surfaces (SHSs) are bio-inspired, artificial microfabricated interfaces, in which a pattern of cylindrical micropillars is modified to incorporate details at the nanoscale. For those systems, the integration of different scales translates into superior properties, including the ability of manipulating biological solutions. The five Ws, five Ws and one H or the six Ws (6W), are questions, whose answers are considered basic in information-gathering. They constitute a formula for getting the complete story on a subject. According to the principle of the six Ws, a report can only be considered complete if it answers these questions starting with an interrogative word: who, why, what, where, when, how. Each question should have a factual answer. In what follows, SHSs and some of the most promising applications thereof are reviewed following the scheme of the 6W. We will show how these surfaces can be integrated into bio-photonic devices for the identification and detection of a single molecule. We will describe how SHSs and nanoporous silicon matrices can be combined to yield devices with the capability of harvesting small molecules, where the cut-off size can be adequately controlled. We will describe how this concept is utilized for obtaining a direct TEM image of a DNA molecule. © 2014 by the authors; licensee MDPI, Basel, Switzerland
Bioartificial Materials Based on Blends of Dextran and Poly(Vinyl Alcohol-co-Acrylic Acid)
No full textRelease of proteinic and non-proteinic compounds from novel ionisable hydrogels: effect of pH on swelling and drug delivery behaviour
No full textRelating the rate of growth of metal nanoparticles to cluster size distribution in electroless deposition
Full text linkElectroless deposition on patterned silicon substrates enables the formation of metal nanomaterials with tight control over their size and shape. In the technique, metal ions are transported by diffusion from a solution to the active sites of an autocatalytic substrate where they are reduced as metals upon contact. Here, using diffusion limited aggregation models and numerical simulations, we derived relationships that correlate the cluster size distribution to the total mass of deposited particles. We found that the ratio ξ between the rates of growth of two different metals depends on the ratio γ between the rates of growth of clusters formed by those metals through the linearity law ξ = 14(γ - 1). We then validated the model using experiments. Different from other methods, the model derives k using as input the geometry of metal nanoparticle clusters, decoded by SEM or AFM images of samples, and a known reference
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
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