In recent years the development of chitosan (CH) based materials as useful adsorbent polymericmatrices is an expanding field in the area of adsorption science. Even though CH has been successfullyused for dye removal from aqueous solutions due to its low cost, no considerations havebeen made about, for example, the effect of changing the pH of chitosan hydrogelor about the dehydratingeffect of Ethanol (EtOH) treatment of chitosan film on the dyes removal from water.Consequently in our laboratory we carried out a study focusing the attention, mainly, on the potentialuse of CH films under different conditions, such as reducing the intrinsic pH, increasing thehydrophobic character by means of ethanol treatment and neutralization of CH films to improvetheir absorption power. Textile anionic dyes named Direct Red 83:1, Direct Yellow 86 and Direct Blue 78 have been studied with the aim of reducing the contact time of CH film in waste water improvingthe bleaching efficiency. Neutralized acid CH film and longtime dehydrated one result tobe the better films in dye removal from water. Also the reduction of the CH solution acidity duringthe film preparation determines the decreasing of the contact time improving the results. The effectof initial dye concentration has been examined and the amount of dye adsorption in functionof time t, qt (mg/cm2), for each analyzed film has been evaluated comparing the long term effectwith the decoloration rate. A linear form of pseudo-first-order Lagergren model has been used anddescribed. The best condition for removing all examined dyes from various dye solutions appearsto be the dehydration of a novel projected CH film obtained by means of the film immersion inEtOH for 4 days. Also CH films prepared by well-known literature procedure and neutralized withNaOH treatment appear having an excellent behavior, however the film treatment requires a largequantity of water and time.

The aim of this study was to explore the potential of novel nanoparticles (NPs)intended for topical administration of the hydrophilic antioxidant Glutathione and thelipophilic Idebenone. Glutathione was introduced into the NPs using two approaches: i)covalently bonded to Chitosan; ii) physically complexed with Idebenone andSulfobutylether-?-cyclodextrin.Methodology: NPs wereformulated using the ionic gelation technique, by dissolving thepolysaccharide-forming matrix (Chitosan, Glycol chitosan, Glutathionyl Chitosan) in wateror in slightly acidic solution. Idebenone was physically entrapped whereas glutathione waseither physically entrapped or covalently bonded to chitosan.Physicochemical characterization of the resulting NPs included size, zeta potentialmeasurements, antioxidant association efficiency, differential scanning calorimetry (DSC)and stability studies. Antioxidants in vitro release from the most stable NPs was assessedwith Franz diffusion cells, and the in vitro antioxidant activity was evaluated by the 2,2diphenyl-1-picrylhydrazyl(DPPH) radical test. NP cytotoxicity was assessed onimmortalized human keratinocytes (HaCaT) cell line.Results: The NPs showed smaller particle size in acidic solution than in aqueousmedium, whereas zeta potential values were always positive, irrespective of the medium.Stability studies led to the choice of the aqueous formulation where Glutathione wascovalently bonded to Chitosan for this study. DSC highlighted amorphization of Idebenonein these NPs. In vitro release studies showed that only Idebenone was released from theNPs. The antioxidant activity test revealed a strong effect (close to 100%) of Idebenoneloaded into NPs while its aqueous solution showed no activity. No cytotoxicity in humankeratinocytes was observed for the investigated NPs.Conclusion: The results of this study suggest that Idebenone can be loaded into ahydrophilic delivery system without organic solvents, often used for its solubilization,possessing high antioxidant activity. Therefore, these nanocarriers represent a promisingstrategy for the design of formulations for topical treatments with antioxidants.

Here we describe the encapsulation in ?-cyclodextrins (?-CDs) of wheat bran, pumpkin and tomato oleoresins, extracted by supercritical carbon dioxide, to obtain freeze-dried powders useful as ready-to-mix ingredients for novel functional food formulation. The stability of tocochromanols, carotenoids and fatty acids in the oleoresin/?-CD complexes, compared to the corresponding free oleoresins, was also monitored over time in different combinations of storage conditions. Regardless of light, storage at 25 °C of free oleoresins determined a rapid decrease in carotenoids, tocochromanols and PUFAs. ?-CD encapsulation improved the stability of most bioactive compounds. Storage at 4 °C synergized with encapsulation in preventing degradation of bioactives. Unlike all other antioxidants, lycopene in tomato oleoresin/?-CD complex resulted to be more susceptible to oxidation than in free oleoresin, likely due to its selective sequestration from the interaction with other lipophilic molecules of the oleoresin

This study reports oil the first monodispersed molecular materials embodying the dibenzothiophene-5,5-dioxide core for the achievement of blue electroluminescence. The core has been functionalised in its 2.8- or 3,7-positions with dimethyl-fluorene (2,8-DBTOF and 3,7-DBTOF) or methyl-carbazole (2,8-DBTOC and 3,7-DBTOC) groups. The obtained compounds were characterised by (1)H and (13)C NMR, APCI-MS, thermal analysis (TGA and DSQ and cyclic voltammetry. Their optical and photophysical properties were investigated by UV and PL measurements as well as by time-dependent density-functional theory calculations. The materials were successfully employed as active layers ill blue to purplish blue p-i-n OLED devices. that reached, in the case of 3,7-DBTOC, performances as high as 11 422 cd m(-2) and 3.25 cd A(-1).

Photodynamic therapy (PDT) is a way of treating malignant tumors and hyperproliferative diseases. It is based on the use of photosensitizer, herein the chlorophyll a (chl a), and a light of an appropriate wavelength. The interaction of the photosensitizer (PS) with the light produces reactive oxygen species (ROS), powerful oxidizing agents, which cause critical damage to the tissue. To solubilize chl a in aqueous solution and to obtain it as monomer, we have used cyclodextrins, carriers which are able to interact with the pigment and form the inclusion complex. The aim of this study is to examine which types of ROS are formed by Chl a/cyclodextrin complexes in phosphate buffered solution and cell culture medium, using specific molecules, called primary acceptors, which react selectively with the reactive species. In fact the changes of the absorption and the emission spectra of these molecules after the illumination of the PS provide information on the specific ROS formation. The 1O2 formation has been tested using chemical methods based on the use of Uric Acid (UA), 9,10-diphenilanthracene (DPA) and Singlet oxygen sensor green (SOSG) and by direct detection of Singlet Oxygen (1O2) luminescence decay at 1270nm. Moreover, 2,7-dichlorofluorescin and ferricytochrome c (Cyt Fe3+) have been used to detect the formation of hydrogen peroxide and superoxide radical anion, which reduces Fe3+ of the ferricytochrome to Fe2+, respectively.

The life cycle of the bacterium Rhodobacter sphaeroides was investigated by isothermal microcalorimetry using two different procedures based on the use of a static ampoule and a flow cell, respectively. In the static ampoule method it is possible to follow the growth phase and also the death phase which cannot be revealed by total biomass based techniques like turbidimetry. However, different cellular metabolisms, possibly due do the oxygen limitation occurring during the bacterial life cycle, produce complex behavior in the experimental curves. In the stop- flow cell mode this limitation is overcome as the bacteria are grown outside the calorimeter under well-defined aerobic conditions and aliquots of cell suspension are transferred in the calorimeter at different time intervals. The complex behavior shown in the static ampoule mode was successfully analyzed by a population evolution model based on a Fujikawa modified logistic equation which provides a quantitative description of the process.

The pH-related characteristics of 4-thiothymidine and its stability during prolonged exposure, at room temperature, to a neon lamp emitting in the 400-700 nm wavelength range were investigated by different spectroscopic techniques (UV-Vis, FTIR-ATR, H-1-NMR) and by ElectroSpray Ionization Mass Spectrometry (ESI-MS). The evaluation of the nucleoside photostability was performed as a control, with the perspective of studying its reactivity under the same conditions but in the presence of visible light-absorbing photosensitizers, able to generate reactive oxygen species. The comparison between UV-Vis spectra recorded at different pH values in the 7-12 range suggested the presence of an equilibrium related to the deprotonation of the N-3-H group of 4-thiothymidine, with a pK(a) estimated to be close to 9. Some effects of the deprotonation occurring at alkaline pH were observed also in FTIR-ATR spectra, the main feature being the appearance of a band related to C=N stretching, interpreted with the assumption of a partial double bond character by C-2-N-3, N-3-C-4 and C-2-O- bonds, as a consequence of negative charge delocalization on the pyrimidine ring. As for photostability, UV-Vis, FTIR-ATR and NMR measurements suggested the generation of thymidine as a by-product but only after a prolonged (48 hours) irradiation time, whereas no significant alteration occurred in a shorter time range (1-2 hours), i.e. the one that will be considered in future studies involving the presence of photosensitizers. The nucleoside stability up to 2 hours of irradiation was confirmed by ESI-MS analyses; furthermore, on the other hand, the latter indicated the presence of three additional by-products, besides thymidine, after 48 hours of irradiation. In particular, an hydroxylated form of 4-thiothymidine and two dimeric species, characterized by S-S and S-O covalent bridges between two 4-thiothymidine and a 4-thiothymidine and a thymidine molecule, respectively, were detected.

The photoreactivity of 4-thiothymidine (S(4)TdR) under visible Eight in the presence of Rose Bengal (RB), acting as a photosensitizer, was investigated in aqueous solutions at pH 7 and 12, using UV-vis, FTIR-ATR and H-1-NMR spectroscopic techniques, time resolved absorption spectroscopy and electrospray ionization mass spectrometry (ESI-MS). Evidence for the generation of thymidine (TdR) as the main product, after one hour of irradiation, was obtained from UV-Vis data, that suggested 4-thiothymidine photodegradation to be faster at basic pH, and confirmed by FTIR-ATR and 1H-NMR data. Clues for the presence of a further product, likely corresponding to a dimeric form of S4TdR, were obtained from the latter techniques. Besides indicating the presence of thymidine, the ESI-MS and MS/MS spectra of the reaction mixtures enabled the identification of the additional product as a S-S bridged covalent dimer of 4-thiothymidine. The concentration of the dimeric species could be estimated with the aid of 1H-NMR data and was found to be lower than that of thymidine in pH 7 reaction mixtures and almost negligible in the pH 12 ones. From a mechanistic point of view, time-resolved absorption spectroscopy measurements provided direct evidence that the formation of the two products cannot be ascribed to a photoinduced electron transfer involving S4TdR and the excited triplet state of RB. Rather, their generation can be interpreted as the result of a bimolecular reaction occurring between singlet state oxygen (102), photogenerated by RB, and S4TdR, as demonstrated by the direct detection of 102 through IR luminescence spectroscopy. More specifically, a sequential reaction pathway, consisting in the generation of an electrophilic hydroxylated form of S(4)TdR and its subsequent, rapid reaction with S(4)TdR, was hypothesized to explain the presence of the S-S bridged covalent dimer of 4-thiothymidine in the reaction mixtures. The described processes make S(4)TdR an interesting candidate in the roEe of molecular probe for the detection of O-1(2) under different pH conditions.