Application of the Shvo catalyst in homogeneous hydrogenation of bio-oil obtained from pyrolysis of white poplar: New mild upgrading conditions

Upgrading of bio-oils obtained from the fast pyrolysis of biomasses requires the development of efficient catalysts able to work under mild conditions and to cope with the complex chemical nature of the reactant. The present work focuses on the use of the ruthenium based Shvo homogeneous catalyst for the hydrogenation of model mixtures (vanillin, cinnamaldehyde, methylacetophenone, glycolaldehyde, acetol, acetic acid) and of a real bio-oil. The hydrogenation of model compounds has been investigated both in mono- and biphasic mixtures under a P(H₂) = 10 atm in the temperature range of 90-145 °C varying the substrate to catalyst molar ratio from 2000:1 to 200:1. Employing the most active reaction conditions (substrate/catalyst 200:1, T = 145 °C, P(H₂) = 10 atm) the Shvo catalyst maintains its performances under acidic “bio-oil conditions” leading to the almost quantitative conversion of the polar double bonds within 1 h. The activity of the Shvo catalyst was also investigated for the hydrogenation of a bio-oil from poplar in solvent free conditions. Hydrogenation deeply changed the chemical nature of the pyrolysis oil. Aldehydes, ketones and non-aromatic double bonds were almost totally hydrogenated. The catalytic system also promoted the hydrolysis of sugar oligomers into monomers.     

Calcium phosphate substrates with emulsion-derived roughness: Processing,characterisation and interaction with human mesenchymal stem cells

Calcium phosphates (CaP) have been the subject of several studies that often lack a systematic approach to understanding how their properties affect biological response. CaP particles functionalised with a pH-responsive polymer (BCS) were used to prepare microporous substrates (porosity between 70 and 75% and pore sizes of 5–20 μm) through the aggregation of oil-in-water emulsions by controlling solid loading, emulsification energy, pH, drying and sintering conditions. The combined effect of surface roughness (roughness amplitude, R_a between 0.9–1.7 μm) and chemistry (varying Hydroxyapatite/β-Tricalcium phosphate ratio) on human mesenchymal stem cells was evaluated. HA substrates stimulated higher cell adhesion and proliferation (especially with lower R_a), but cell area increased with β-TCP content. The effect of surface roughness depended of chemistry: HA promoted higher mineralising activity when R_a ～ 1.5 μm, whereas β-TCP substrates stimulated a more osteogenic profile when R_a ～ 1.7 μm. A novel templating method to fabricate microporous CaP substrates was developed, opening possibilities for bone substitutes with controlled features.     

Hybrid Polyoxometalates: Merging Organic and Inorganic Domains for Enhanced Catalysis and Energy Applications

Organic–inorganic hybrids based on polyoxometalate scaffolds(POMs) are a unique class of molecular metal-oxides featuring a composite surface, whereby the merging of complementary domains stimulates new functions and enhances performances. The interaction between the organic and inorganic components can be designed via covalent and/or non-covalent strategies, yielding novel molecular systems with key applications in catalysis and materials science. Selected examples of such a rewarding approach will be illustrated, including the synthesis of tailored POM-based catalysts, and their application in homogeneous systems and on electrocatalytic surfaces for water splitting and renewable energy production.     

Absorption and reflection of infrared radiation by polymers in fire‐like environments

In large‐scale fires, the input of energy to burning materials occurs predominantly by radiative transfer. The in‐depth (rather than just surface) absorption of radiant energy by a polymer influences its ignition time and burning rate. The present investigation examines two methods for obtaining the absorption coefficient of polymers for infrared radiation from high‐temperature sources: a broadband method and a spectral method. Data on the total average broadband transmittance for 11 thermoplastics are presented (as are reflectance data), and the absorption coefficient is found to vary with thickness. Implications for modeling of mass loss experiments are discussed. Copyright © 2011 John Wiley & Sons, Ltd.     

Synthesis and Biological Studies of Pyrazolyl‐Diamine PtII Complexes Containing Polyaromatic DNA‐Binding Groups

New [PtCl(pz*NN)]ⁿ⁺ complexes anchored by pyrazolyl‐diamine (pz*NN) ligands incorporating anthracenyl or acridine orange DNA‐binding groups have been synthesized so as to obtain compounds that would display synergistic effects between platination and intercalation of DNA. Study of their interaction with supercoiled DNA indicated that the anthracenyl‐containing complex L²Pt displays a covalent type of binding, whereas the acridine orange counterpart L³Pt shows a combination of intercalative and covalent binding modes with a strong contribution from the former. L²Pt showed a very strong cytotoxic effect on ovarian carcinoma cell lines A2780 and A2780cisR, which are, respectively, sensitive to and resistant to cisplatin. In these cell lines, L²Pt is nine to 27 times more cytotoxic than cisplatin. In the sensitive cell line, L³Pt showed a cytotoxic activity similar to that of cisplatin, but like L²Pt was able significantly to overcome cisplatin cross‐resistance. Cell‐uptake studies showed that L²Pt accumulates preferentially in the cytoplasm, whereas L³Pt reaches the cell nucleus more easily, as clearly visualized by time‐lapse confocal imaging of live A2870 cells. Altogether, these findings seem to indicate that interaction with biological targets other than DNA might be involved in the mechanism of action of L²Pt because this compound, despite having a weaker ability to target the cell nucleus than L³Pt , as well as an inferior DNA affinity, is nevertheless more cytotoxic. Furthermore, ultrastructural studies of A2870 cells exposed to L²Pt and L³Pt revealed that these complexes induce different alterations in cell morphology, thus indicating the involvement of different modes of action in cell death.     

Multifunctional TiO2 coatings for Cultural Heritage

Environmental pollution arising from industrial implants and urban factors is constantly increasing, causing aesthetical and durability concerns to urban structures exposed to the atmosphere.     

Optimized production of a high-performance hybrid biomaterial: biomineralized spider silk for bone tissue engineering

Silks have been widely used as biomaterials due to their biocompatibility, biodegradability, and excellent mechanical properties. In the present work, native spider silk was used as organic template for controlled nucleation of hydroxyapatite (HA) nano-coating that can act as biomimetic interface. Different bio-inspired neutralization methods and process parameters were evaluated to optimize the silk functionalization. The morphology and chemical composition were investigated by scanning electron microscopy, energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, and X-ray diffraction analysis and mechanical properties were studied through tensile tests. Results showed that the optimized protocol enabled a controlled and homogeneous nucleation of apatite nano-crystals while maintaining silk mechanical performances after mineralization. This study reports the optimization of a simple and effective bio-inspired nucleation process for precise nucleation of HA onto spider silk templates, suitable to develop high-performance hybrid interfaces for bone tissue engineering. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48739.