DODAB/Monoolein mixed cationic liposomes for gene delivery : investigation by DLS, DSC, fluorescence spectroscopy and phase scanning microscopy

FCT and FEDER for financial support to CFUM and also by funding through project PTDC/QUI/69795/2006 and PhD grant of J.P.N. Silva (SFRH/BD/46968/2009)

Modelling microbial load reduction in foods due to ozone impact

Ozone is a strong sanitizer that can be applied as a convenient washing-treatment to foods. The main objective was to study the ozone impact on Listeria innocua in red bell peppers, total mesophiles in strawberries and total coliforms in watercress. Modelling microbial load reduction throughout treatment time and due to ozone effect were also targets. The microbiological reductions observed for ozonated samples were higher than the ones obtained for water dipping. However, total coliforms/watercress were less sensitive to both deionized-water and ozonated-water washings. A Weibull-based model was adequate in describing microbiological reductions and may contribute to design more effective sanitizing processes

Supramolecular ultra-short dehydropeptide-based hydrogels as potential affordable nanocarriers

A library of Cbz-protected dehydrodipeptides was synthesised and evaluated as minimalist hydrogels. The molecular aggregation, self-assembly, gelation and biocompatibility were thoroughly studied through fluorescence spectroscopy, and the mechanical properties were assessed. The compounds that afforded hydrogels were evaluated as drug delivery systems for curcumin and doxorubicin using biomembrane models.UIDB/04650/2020; UIDB/00686/2020; PTDC/QUI-QFI/28020/2017; PTDC/QUI-QOR/29015/2017; SFRH/BD/144017/201

Influence of contact lens care solutions on the water content of hydrogel and silicone-hydrogel contact lenses

Purpose The aim of this work was to study variations in water content (WC) of hydrogel and silicone-hydrogel contact lenses (CL) when preserved in different lens care systems. Material and Method Four silicone-hydrogel CL (Senofilcon A, Balafilcon A, Comfilcon A, Lotrafilcon B) and one conventional CL (Etafilcon A) and commercially available lens care solutions (Renu Multiplus™ and Biotrue (Bausch & Lomb), Optifree Puremoist and Aosept® Plus (CIBA Vision) were used. Lenses were immersed in each lens care system during 12 hours and then RI was determined with the digital automated refractometer (CLR 12-70, Index Instruments, 174 Cambridge, UK). Water content was directly obtained with this instrument using RI values and the equation given in BSO ISO 10339:1997. Measurements were performed before and after the lenses have been immersed in each care solution. Two CL of each combination (CL + solution) were tested, and five measurements per lens were obtained. Results The mean values of WC (in %) obtained for each lens material when CL were removed from their blisters (baseline value) was for: Etafilcon A (55.75 ± 0.52); Comfilcon A (45.84 ± 0.28); Senofilcon A (37.01 ± 0.98), Lotrafilcon B (25.53 ± 0.42) and Balafilcon A (34.61 ± 1.03). Substantial changes and statistically significant were observed on these parameters when exposed to lens care systems depending on the CL material and the solution. Senofilcon A decreased the WC with all the solutions contrary of lotrafilcon B where it was observed an increase in WC with all the solutions. Comfilcon A remained approximately with the same values of WC. Balafilcon A and Etafilcon A showed an irregular behavior increasing or decreasing depending on the solution. Conclusions The present study reveals that solutions induce changes in the CL properties studied showing the existence of interactions between CL material and lens care solution. These interactions can be essential when eye care practitioners choose the most appropriate lens care product for CL, especially when the patient present symptoms of discomfort or dryness.info:eu-repo/semantics/publishedVersio

Supramolecular plasmonic magnetic gels for controlled drug delivery

In this work, two different magnetic/plasmonic nanoparticle architectures were developed, characterized and combined with a naproxen N-capped dehydropeptide-based hydrogel. Spectroscopic techniques and rheologic assays were used were used to assess the gel physicochemical properties, the incorporation of a model drug (curcumin), drug transport towards model membranes and controlled drug release

Monitoring of a slaughterhouse wastewater treatment plant – case study

O presente trabalho teve como objetivo caracterizar as águas residuais produzidas num matadouro, determinar as eficiências do processo de tratamento e propor medidas de melhoria. Da caracterização das águas residuais constatou-se que o efluente final cumpriu com os valores limite de emissão, exceto para o fósforo. De um modo geral, obtiveram-se eficiências de remoção dos poluentes superiores a 73%. Em relação aos parâmetros operacionais, verificou-se que o valor de F/M, entre 0,05 e 0,15 kgCBO5.kg-1MLVSS.d-1, é importante para aumentar a eficiência do processo. Aumentando a quantidade de coagulante e floculante a adicionar nas DAF’s, ocorrerá uma maior produção de lamas e consequente remoção de fósforo. Constatou-se que a manutenção adequada da purga de lamas permite a redução da biomassa no reator e aumenta a razão F/M.The present work aims to characterize the slaughterhouse wastewater treatment, calculate the treatment efficiency and recommend improvement measures. From the wastewater characterization it was noted that the final effluent complies with the emission limit values, except for phosphorus. Overall, removal efficiencies obtained for pollutants were higher than 73%. What concerns the operational parameters, it was found that F/M value, between 0.05 and 0.15 kgCBO5.kg-1MLVSS.d-1, is important to increase efficiency. Increasing the coagulant and flocculant amount in the DAF, the sludge production increases and consequently the phosphorus removal. The sludge purging allows the reduction of biomass in the reactor and increase the F/M ratio.info:eu-repo/semantics/publishedVersio

Study on thermosonication and ultraviolet radiation processes as an alternative to blanching for some fruits and vegetables

The impacts of ultraviolet-C radiation, blanching by heat, and combination of heat/ultrasounds (thermosonication) were studied for Listeria innocua (inoculated) in red bell peppers, total mesophiles in strawberries and total coliforms in watercress, in the temperature range 50–65 °C. Quality attributes such as colour and firmness were studied for all products, and total anthocyanins content was additionally determined for strawberries. Results showed that ultraviolet- C radiation was the least effective treatment in terms of microbial load reduction and was equivalent to a simple water washing. Log reductions were 1.05±0.52 for L. innocua, 0.53±0.25 for total coliforms and 0.26±0.18 for total mesophiles. This treatment had the lowest impact on the quality parameters analysed. Thermosonication treatment was similar to heat blanching for all microorganism/product tested, excepted for total coliforms in watercress at 65 °C, in which thermosonication had a higher effect (p<0.05). Heat blanching at 65 °C allowed 7.43±0.12 log-cycles reduction, while loads were diminished by 8.24±0.13 log-cycles if thermosonication at the same temperature was applied. Thermosonication also allowed better quality retention, when compared to heat blanching at the same temperatures. The impact of thermosonication on microbial load reductions was statistically significant and thermosonicated samples retained quality attributes better than heat blanched ones at the same temperatures (p<0.05). Hence, it can be concluded that thermosonication is a promising process and may be a favourable alternative to the conventional thermal treatments