12 research outputs found

    Synthesis and in-situ ATR studies of nanostructured titania photocatalysts for the degradation of aqueous organic pollutants

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    Water is a crucial resource for life but only 3% of global water is fresh and this small amount is ever decreasing due to unwise human activities. Traditional biological treatments require further chemical processing to degrade recalcitrant molecules and the processing of such chemicals necessitates large energy inputs and high costs. Heterogeneous photocatalysis provides a green solution as it harnesses the power of natural sunlight. Titanium dioxide is one of the most extensively studied photocatalysts due to low toxicity, chemical stability and low cost. Despite the powerful intrinsic oxidating ability drawbacks in commercial titania materials stem from the relatively high band gap energy and low surface areas. To overcome this, in this research the aim is to synthesis a novel material which can maximize the efficiency of photocatalytic processes applied to depollution of waste water. Mesoporous silicas with tunable parameters were employed as supports for the anchoring of surface titania species, in order to improve the available active surface area of the catalyst. Highly sophisticated analytical techniques common to the fields of surface science and heterogeneous catalysis were applied to fully characterize the prepared materials and determine structure-function relationships. Screening for the photocatalytic activity of the synthesized materials was performed in jacketed quartz batch reactor irradiated by a UV-vis light source against common organic dyes. Photoactivity of the prepared materials was investigated alongside commercially available titania catalysts to act as benchmarks. In heterogeneous catalysis it is vital to study the interaction between the surface of the catalyst and the probe molecules, including adsorptive and desorptive processes occurring at the solid-liquid interface. ATR-IR spectroscopy was used to investigate this aspect of our reaction, allowing for real time monitoring of reaction kinetics with the use of an innovative flow cell chamber, fit with a quartz window allowing for in-situ UV irradiation

    Engineered Cartilage Maturation Regulates Cytokine Production and Interleukin-1β Response

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    Background: Because the injured joint has an actively inflammatory environment, the survival and repair potential of cartilage grafts may be influenced by inflammatory processes. Understanding the interactions of those processes with the graft may lead to concepts for pharmacologic or surgical solutions allowing improved cartilage repair. Questions/purposes: We asked whether the maturation level of cartilaginous tissues generated in vitro by expanded human articular chondrocytes (HACs) modulate (1) the spontaneous production of cytokines and (2) the response to interleukin (IL)-1β. Methods: Twelve pellets/donor prepared with monolayer-expanded HACs (n=6 donors) were evaluated at six different culture times for mRNA expression (n=72) and spontaneous baseline release of monocyte chemoattractant protein (MCP)-1, IL-8, and transforming growth factor (TGF)-β1 (n=72). We cultured 24 pellets/donor from each of four donors for 1 or 14days (defined as immature and mature, respectively) and exposed the pellets to IL-1β for 3days. MCP-1, IL-8, TGF-β1, and metalloprotease (MMP)-1 and MMP-13 were quantified in pellets and culture supernatants. Results: By increasing culture time, the spontaneous release of IL-8 and MCP-1 decreased (12.0- and 5.5-fold, respectively), whereas that of TGF-β1 increased (5.4-fold). As compared with immature pellets, mature pellets responded to IL-1β by releasing lower amounts of MMP-1 (2.9-fold) and MMP-13 (1.7-fold) and increased levels of IL-8, MCP-1, and TGF-β1 (1.5-, 5.0-, and 7.5-fold, respectively). IL-8 and MCP-1 promptly returned to baseline on withdrawal of IL-1β. Conclusions: Our observations suggest more mature cartilaginous tissues are more resistant to IL-1β exposure and can activate chemokines required to initiate tissue repair processes. Clinical Relevance: The implantation of more mature cartilaginous tissues might provide superior graft survival and improve/accelerate cartilage repai

    Tunable Silver-Functionalized Porous Frameworks for Antibacterial Applications

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    Healthcare-associated infections and the rise of drug-resistant bacteria pose significant challenges to existing antibiotic therapies. Silver nanocomposites are a promising solution to the current crisis, however their therapeutic application requires improved understanding of underpinning structure-function relationships. A family of chemically and structurally modified mesoporous SBA-15 silicas were synthesized as porous host matrices to tune the physicochemical properties of silver nanoparticles. Physicochemical characterization by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), X-ray absorption near-edge spectroscopy (XANES) and porosimetry demonstrate that functionalization by a titania monolayer and the incorporation of macroporosity both increase silver nanoparticle dispersion throughout the silica matrix, thereby promoting Ag₂CO₃ formation and the release of ionic silver in simulated tissue fluid. The Ag₂CO₃ concentration within functionalized porous architectures is a strong predictor for antibacterial efficacy against a broad spectrum of pathogens, including C. difficile and methicillin-resistant Staphylococcus aureus (MRSA)

    Glossario e bibliografia

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    Glossario organizzato secondo quattro macro-aree (Uomo, Prodotto, Ambiente, Sistema) di parole-chiave e loro declinazione in ambito sistemico. Bibliografia essenziale su tematiche sistemich

    Engineered cartilage maturation regulates cytokine production and interleukin-1beta response

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    BACKGROUND: Because the injured joint has an actively inflammatory environment, the survival and repair potential of cartilage grafts may be influenced by inflammatory processes. Understanding the interactions of those processes with the graft may lead to concepts for pharmacologic or surgical solutions allowing improved cartilage repair. QUESTIONS/PURPOSES: We asked whether the maturation level of cartilaginous tissues generated in vitro by expanded human articular chondrocytes (HACs) modulate (1) the spontaneous production of cytokines and (2) the response to interleukin (IL)-1beta. METHODS: Twelve pellets/donor prepared with monolayer-expanded HACs (n = 6 donors) were evaluated at six different culture times for mRNA expression (n = 72) and spontaneous baseline release of monocyte chemoattractant protein (MCP)-1, IL-8, and transforming growth factor (TGF)-beta1 (n = 72). We cultured 24 pellets/donor from each of four donors for 1 or 14 days (defined as immature and mature, respectively) and exposed the pellets to IL-1beta for 3 days. MCP-1, IL-8, TGF-beta1, and metalloprotease (MMP)-1 and MMP-13 were quantified in pellets and culture supernatants. RESULTS: By increasing culture time, the spontaneous release of IL-8 and MCP-1 decreased (12.0- and 5.5-fold, respectively), whereas that of TGF-beta1 increased (5.4-fold). As compared with immature pellets, mature pellets responded to IL-1beta by releasing lower amounts of MMP-1 (2.9-fold) and MMP-13 (1.7-fold) and increased levels of IL-8, MCP-1, and TGF-beta1 (1.5-, 5.0-, and 7.5-fold, respectively). IL-8 and MCP-1 promptly returned to baseline on withdrawal of IL-1beta. CONCLUSIONS: Our observations suggest more mature cartilaginous tissues are more resistant to IL-1beta exposure and can activate chemokines required to initiate tissue repair processes. CLINICAL RELEVANCE: The implantation of more mature cartilaginous tissues might provide superior graft survival and improve/accelerate cartilage repair

    Glossario e bibliografia

    No full text
    Glossario organizzato secondo quattro macro-aree (Uomo, Prodotto, Ambiente, Sistema) di parole-chiave e loro declinazione in ambito sistemico. Bibliografia essenziale su tematiche sistemich

    Glossary and bibliography

    No full text
    Glossary organized in four main areas (Man, Product, Environment, System) of keywords and their variation within the systemic ambit. Essential bibliography on systemic issues
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