Bacteria‐Resistant Single Chain Cyclized/Knotted Polymer Coatings

Further to conventional linear, branched, crosslinked, and dendritic polymers, single chain cyclized/knotted polymers (SCKPs) have emerged as a new class of polymer structure with unique properties. Herein, the development of bacteria‐resistant SCKPs is reported and the effect of this structure on the resistance of polymer materials to bacteria is investigated. Four SCKPs were synthesized by reversible addition fragmentation chain transfer (RAFT) homopolymerization of multivinyl monomers (MVMs) and then crosslinked by UV light to form SCKP films. Regardless of MVM type used, the resulting SCKP films showed much higher resistance to bacteria, and up to 75 % less bacterial attachment and biofilm formation, in comparison with the corresponding non‐SCKP films. This is due to the altered surface morphology and hydrophobicity of the SCKP films. These results highlight the critical role of the SCKP structure in enhancing the resistance of polymeric materials to bacteria.     

Identification of Protein Functional Regions

Protein sequence stores the information relative to both functionality and stability, thus making it difficult to disentangle the two contributions. However, the identification of critical residues for function and stability has important implications for the mapping of the proteome interactions, as well as for many pharmaceutical applications, e. g. the identification of ligand binding regions for targeted pharmaceutical protein design. In this work, we propose a computational method to identify critical residues for protein functionality and stability and to further categorise them in strictly functional, structural and intermediate. We evaluate single site conservation and use Direct Coupling Analysis (DCA) to identify co-evolved residues both in natural and artificial evolution processes. We reproduce artificial evolution using protein design and base our approach on the hypothesis that artificial evolution in the absence of any functional constraint would exclusively lead to site conservation and co-evolution events of the structural type. Conversely, natural evolution intrinsically embeds both functional and structural information. By comparing the lists of conserved and co-evolved residues, outcomes of the analysis on natural and artificial evolution, we identify the functional residues without the need of any a priori knowledge of the biological role of the analysed protein.     

Compatibility of paroxetine hydrochloride and GW597599B

In this study, we present a full thermal characterization of antidepressant paroxetine and summarize the results for another drug which treats depression: GW597599B. The main aim is to analyze how the thermodynamic and structural properties of these compounds are modified when the two drugs are mixed in the solid state. We begin by putting into evidence how dehydration and melting concur in shaping the calorimetric curves of paroxetine under different experimental conditions. Equipped with this knowledge, we are able to interpret the thermal response of the physical mixtures paroxetine:GW597599B, in terms of partial eutectic formation and simple superposition of contribution from the two compounds.     

Comparison of three different enrichment strategies for serum low molecular weight protein identification using shotgun proteomics approach

Serum low-molecular weight (LMW) proteins potentially contain useful biological information and their identification can be used to discover novel potential biomarkers. Given the high complexity of serum samples, in the last years several different prefractionation and enrichment strategies have been developed. In this study three different methods, i.e. hydrogel nanoparticles, Proteominer^® peptide ligand affinity beads and Sartorius Vivaspin^® centrifugal ultrafiltration device, were compared and evaluated in order to select the best strategy for the enrichment and prefractionation of LMW proteins. A shotgun proteomics approach was adopted, with in-solution proteolytic digestion of the whole protein mixture and determination of the resulting peptides by nanoHPLC coupled with a high-resolution Orbitrap LTQ-XL mass spectrometer. Data analysis, focusing on the LMW proteome (MW ≤ 40 kDa), has shown that the hydrogel nanoparticles performed better in enriching the LMW protein profiles, with 115 proteins identified against 93 and 95 for Proteominer^® beads and Sartorius Vivaspin^® device, respectively.     

Acid/Vanadium‐Containing Saponite for the Conversion of Propene into Coke: Potential Flame‐Retardant Filler for Nanocomposite Materials

Vanadium‐containing saponite samples were synthesized in a one‐pot synthetic procedure with the aim of preparing samples for potential application as fillers for polymeric composites. These vanadium‐modified materials were prepared from an acid support by adopting a synthetic strategy that allowed us to introduce isolated structural V species (H/V‐SAP). The physicochemical properties of these materials were investigated by XRD analysis and by DR‐UV/Vis and FTIR spectroscopy of CO that was adsorbed at 100 K; these data were compared to those of a V‐modified saponite material that did not contain any Brønsted acid sites (Na/V‐SAP). The surface‐acid properties of both samples (together with the fully acidic H‐SAP material and the Na‐SAP solid) were studied in the catalytic isomerization of α‐pinene oxide. The V‐containing solids were tested in the oxidative dehydrogenation reaction of propene to evaluate their potential use as flame‐retardant fillers for polymer composites. The effect of tuning the presence of Lewis/Brønsted acid sites was carefully studied. The V‐containing saponite sample that contained a marked presence of Brønsted acid sites showed the most interesting performance in the oxidative dehydrogenation (ODH) reactions because they produced coke, even at 773 K. The catalytic data presented herein indicate that the H/V‐SAP material is potentially active as a flame‐retardant filler.     

Layer-by-layer deposition of a polythiophene/Au nanoparticles multilayer with effective electrochemical properties

Multilayers consisting of a water soluble polythiophene derivative and Au nanoparticles have been deposited onto different electrode substrates by means of layer-by-layer deposition technique. The assembly of the films has been performed by taking advantage of the electrostatic interactions between the positively charged imidazolic moiety of the polythiophene chain and the negative charges of citrate ions surrounding Au nanoparticles, as well of the affinity of S to Au. The nanoparticles result stably grafted to the organic matrix. The resulting modified electrodes have been characterised through electrochemical, spectroelectrochemical and microscopic techniques. The results evidenced that a high number of individual nanoparticles is present inside the multilayer. The presence of nanoparticles is of chief importance for most effective charge percolation through the multilayer, as suggested by the responses to electroactive probe species in solution. The electrocatalytic performances of the modified electrodes have been tested with respect to the oxidation of ascorbic acid.     

Mechanically assisted solid state synthesis of Mg2SnO4

Simultaneous TG?CDSC measurements have been used to study the solid state reaction in the system SnC₂O₄?C4MgCO₃·Mg(OH)₂·xH₂O (Sn:Mg?=?0.5). The results obtained with physically prepared mixture and with mixture mechanically activated by high-energy milling are compared. Synthesis of the compound Mg₂SnO₄ has been attempted starting from both type of mixture: Mg₂SnO₄ forms by annealing the activated mixture at temperatures between 850 and 1,000?°C while it can hardly be obtained from physical mixtures even by thermal treatment at temperature as high as 1,300?C1,350?°C. Mg₂SnO₄ prepared by annealing the activated mixture has been characterized by diffuse reflectance FT-IR spectroscopy, modulated temperature differential scanning calorimetry, scanning electron microscopy, and specific surface area measurements (B.E.T. method).     

Silica Monolith for the Removal of Pollutants from Gas and Aqueous Phases

This study focused on the application of mesoporous silica monoliths for the removal of organic pollutants. The physico-chemical textural and surface properties of the monoliths were investigated. The homogeneity of the textural properties along the entire length of the monoliths was assessed, as well as the reproducibility of the synthesis method. The adsorption properties of the monoliths for gaseous toluene, as a model of Volatile Organic Compounds (VOCs), were evaluated and compared to those of a reference meso-structured silica powder (MCM-41) of commercial origin. Silica monoliths adsorbed comparable amounts of toluene with respect to MCM-41, with better performances at low pressure. Finally, considering their potential application in water phase, the adsorption properties of monoliths toward Rhodamine B, selected as a model molecule of water soluble pollutants, were studied together with their stability in water. After 24 h of contact, the silica monoliths were able to adsorb up to the 70% of 1.5 × 10⁻² mM Rhodamine B in water solution.