Polysaccharide-based hydrogels are achieving remarkable performances in chronic wounds treatment. In this work, a carboxymethyl cellulose-based hydrogel film was developed to support skin repair. The ...hydrogel was loaded with berberine, a polyphenolic molecule endowing antioxidant and cytoprotective features. The film was physico-chemically characterized and in vitro tested on keratinocytes and fibroblasts subjected to oxidative stress. The biocomposite showed high thermal stability (onset decomposition temperature 245 °C) and significant fluid uptake performances, both in free conditions (up to 6510%) and under external pressure (up to 3400%). Moreover, it was able to control oxidative stress and inflammation markers involved in wound chronicity. Keratinocytes hyperproliferation, features that normally hamper injury restoration, was reduced of 25%. Our results showed that the combination of berberine and hydrogel provides a synergic improvement of the material properties. The biocomposite represents a promising candidate for dermatological applications against oxidative stress at the chronic wound site, promoting the healing process.
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The guarantee of the origin and quality of raw material is essential for the protection and valorization of Campana buffalo mozzarella cheese. The risk of utilization of semifinished products and ...stored milk in substitution for fresh milk is increasing, due to the continuous desire to reduce production costs. A proteomics approach and electrophoresis survey of retail mozzarella cheeses indicated different rates of proteolysis in the production of dairy industries. The use of fresh milk and correct cheesemaking protocol yielded only γ-caseins, which are derived from β-casein by plasmin, and para-κ-casein, which is derived from κ-casein by chymosin. The detection of abnormal hydrolysis resulting in β- and αS1-casein fragments, identified by mass spectrometry, indicates the use of stored milk or stored and pressed curd, or the reuse of unsold mozzarella cheese, to produce mozzarella. The formation of γ-caseins and other fragments during a long storage of raw materials at room or refrigeration temperature was ascribed to plasmin (endogenous milk enzyme), whereas formation of αS1-casein fragments, mainly αS1-I6P- and αS1-I7P-casein during the storage of curd was ascribed to the action of chymosin (exogenous enzyme) from rennet. Sodium dodecyl sulfate-PAGE and alkaline urea-PAGE permitted us to evaluate the freshness of the raw materials used in the manufacturing of buffalo mozzarella cheese and to reveal possible inappropriate preservation.
The causes of the spectral instability of poly9,9‐dioctylfluoren‐2,7‐diyl‐co‐2′,7′‐spiro(cyclohexane‐1,9′‐fluorene) during thermal annealing in air, which leads to a green photoluminescence (PL) ...emission band, are investigated. The Igreen/Iblue ratio evolution (I = intensity) is found to be independent of the amount of monoalkylfluorene defects, despite the fact that their presence might be regarded as a trigger for the radical process leading to polymer degradation in the presence of a trace amount of metal catalyst. Furthermore, the absence of a correlation between the degree of oxidation of the material and the Igreen/Iblue ratio indicates that the spatial disposition of fluorenones formed during the thermal degradation of the material, rather than their amount, is to be strictly related to the Igreen/Iblue ratio. The evidenced formation of fluorenone agglomerates, which could be considered the cause for the consistent increase in the Igreen/Iblue ratio during a thermal oxidation of a polyfluorene, confirms that the radical mechanism can also involve dialkylfluorene systems. Finally, the higher resistance to thermal degradation shown by spirocyclohexane fluorene units with respect to dioctylfluorene ones allows the synthesis of new, spectrally stable, fluorene‐based copolymers.
Spectral stability of polyfluorenes is addressed by investigating the possible pathways of their radical degradation, the effect of the formation of fluorenone agglomerates, and the role of metal impurities in triggering the oxidation process. New, spectrally stable spirofluorene copolymers are prepared (see figure).
•Geographic origin of sweet cherries was characterised by NMR and statistics tools.•1H NMR was used in a nontargeted fingerprinting approach.•PLS-DA and LDA gave the best classification and ...prediction performances.•Different strategies for variable number reduction were tested.•External validation procedures were applied on the classification models.
In this study, non-targeted 1H NMR fingerprinting was used in combination with multivariate statistical techniques for the classification of Italian sweet cherries based on their different geographical origins (Emilia Romagna and Puglia). As classification techniques, Soft Independent Modelling of Class Analogy (SIMCA), Partial Least Squares Discriminant Analysis (PLS-DA), and Linear Discriminant Analysis (LDA) were carried out and the results were compared. For LDA, before performing a refined selection of the number/combination of variables, two different strategies for a preliminary reduction of the variable number were tested. The best average recognition and CV prediction abilities (both 100.0%) were obtained for all the LDA models, although PLS-DA also showed remarkable performances (94.6%). All the statistical models were validated by observing the prediction abilities with respect to an external set of cherry samples. The best result (94.9%) was obtained with LDA by performing a best subset selection procedure on a set of 30 principal components previously selected by a stepwise decorrelation. The metabolites that mostly contributed to the classification performances of such LDA model, were found to be malate, glucose, fructose, glutamine and succinate.
This work focuses on the assessment, in terms of effectiveness, feasibility and sustainability, of three different procedures for the synthesis of vanadium-based mixed-acid electrolytes to be used in ...vanadium redox-flow batteries (VRFBs). Procedures considered consisted in: a) the mere mixing of suitable vanadium precursors (Electrolyte A); b) the chemical reduction of V2O5 by oxalic acid (Electrolyte B); c) the electrochemical reduction of V2O5 using a home-made “H-shaped” electrolysis cell (Electrolyte C). VRFB properties such as energy efficiency, mean charge–discharge voltages, cycle duration as well as stability and conductivity of the electrolyte were analysed and compared with the state-of-the-art. Experimental tests carried out on a laboratory scale VRFB battery comprised: thermal stability test, cyclic voltammetry, electrochemical impedance spectroscopy measurements and charge–discharge tests. A Life Cycle Assessment of the three electrolytes is also presented for benchmarking purposes.
•Assessing sustainability of vanadium redox-flow battery electrolyte through advanced LCA tools (ISO 14040).•Sustainable experimental synthesis procedures of vanadium electrolytes.•Cradle-to-gate LCA comparison with local specific data.•Syntheses of mixed acid vanadium electrolytes for VRFB are compared in terms of effectiveness and sustainability.
This review covers the last 12 years of research on the synthesis and use of heterogeneous catalysts obtained by co-polymerization of suitable metal containing monomers (MCM). The catalytic ...applications of these supported metal complexes are subdivided into three areas. Hydrogenation of alkenes and functionalized olefins are covered first. Oxidation of several substrates such as olefins, sulfides, alcohols, and aldehydes are then considered. Of particular interest in this framework is the use of chiral salen metal containing monomers for the stereoselective epoxidation of hindered olefins. Alkene and alkyne polymerizations, Heck and Heck-type reactions, allylic alkylation, and Michael additions are discussed in the field of carboncarbon bond forming reactions. A common factor emerging from this survey is the application of metal containing monomers for the synthesis of molecularly imprinted polymers to be used as catalysts or catalyst supports.
Spin-coated films of 29H,31H-tetra-4-(2,4-di-
tert-amylphenoxy)phthalocyanine (H
2Pc) and κ
P,μ-κ
S-(dppeS)Pt(CH
3)
2BF
4
2 have been used as sensing layers deposited in thin film form for the ...detection of VOCs. The sensing behaviour of the blend was predicted on the basis of mass spectrometric determinations performed on H
2Pc/Pt-complex solutions, by monitoring the formation of gas-phase ions at the electrospray interface. The addition of small amounts of acetonitrile produced a
M
+
41
+ peak whereas the addition of similar amounts of methanol, ethanol and isopropyl alcohol did not give the corresponding
M
+
ROH
+ species. These results were confirmed by sensing tests. A pure phthalocyanine optosensing element did not show relevant selectivity. Conversely, the heterogeneous sensing layer obtained by spin-coating deposition of a Pt-complex/H
2Pc blend allowed the sensing of acetonitrile vapours with respect to the above mentioned alcohols.
The catalytic activity of the cross-linked polymer obtained by reaction of Pd(AAEMA)
2 HAAEMA=2-(acetoacetoxy)ethyl methacrylate and suitable acrylates as comonomers and cross-linkers was ...investigated in the hydrogenation reactions of substrates such as olefins, aromatic and unsaturated aldehydes, unsaturated ketones and nitrocompounds. The polymer-supported palladium was found to be active and recyclable without loss of metal.
•One-step synthesis of sub-micrometric Calcium Hydroxide/Chitosan hybrid catalyst•Biodiesel production with yield up to 98 % and recyclability up to 10 cycles•No calcination step was required for ...catalyst preparation.•Kinetics and mechanistic insights were provided for heterogeneous catalysis.•Full characterization demonstrated high Ca loading onto the biopolymer.
In this work, a novel supported catalyst was prepared starting from calcium chloride and chitosan flakes using a very mild approach in an aqueous medium without final calcination at high temperatures. The as-prepared catalyst was fully characterized by thermogravimetric analysis (TGA), attenuated total reflectance Fourier transform infrared (ATR-FTIR), and X-ray photoelectron (XPS) spectroscopies, transmission and scanning electron microscopies (TEM, SEM), Energy Dispersive X-ray Spectroscopy (EDS), demonstrating that it consists of calcium hydroxide particles of about 200 nm supported on chitosan micrometric structures. The most crucial parameters in the transesterification process were investigated. A methanol/oil ratio of 6:1, a reaction time of 6 h, and a temperature of 60 °C were found to lead to complete conversion. A reaction on a gram scale using waste oil as a starting material was also tested, and excellent results were achieved. Moreover, the catalyst proved to be very robust, since even after the 10th recycle, the conversion rate remained at around 90 %. Spectroscopic analyses showed minimal leaching of material without modification of chemical composition. The kinetic behavior (activation energy, Ea) of the catalyst was also studied, which resulted in similar outcomes to Ca-based systems present in the literature, but without the need for costly preparations and with superior recycling resistance. An Ea value of 63.25 kJ·mol−1 was found, which agrees with data reported in the literature.
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The aerobic oxidation of substituted phenols with the catalytic system M(acac)
n
/3-methylbutanal/O
2 has been investigated. Co(acac)
2 and Mn(acac)
3 promoted the transformation of ...2,6-dimethylphenol and 2,6-di-
t-butylphenol into their corresponding diphenoquinones and benzoquinones. In the oxidation of 2,3,6-trimethylphenol, the same catalysts yielded 32–34% of the relevant biphenol. Cu(acac)
2 converted 2-naphthol into 1,1′-bi-2-naphthol with 84% yield. Supported Co(II) and Cu(II) complexes have also been used as heterogeneous catalysts for the oxidation of 2,6-di-
t-butylphenol and 2-naphthol, respectively.
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