221 research outputs found

    The Effect of Light Wavelength on CO2 Capture, Biomass Production and Nutrient Uptake by Green Microalgae: A Step Forward on Process Integration and Optimisation

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    Microalgae have drawn the attention of several researchers as an alternative to the traditional physicochemical CO2 capture methods, since they can convert CO2 and water into organic matter and release oxygen into the atmosphere. Microalgal growth can be improved by changing light supply, such as light intensity, wavelength, and photoperiod. In this study, the effect of different light wavelengths on CO2 capture, nutrient removal from a synthetic effluent and biomass production of Chlorella vulgaris, Tetradesmus obliquus and Neochloris oleoabundans was studied. The experiments were conducted with light-emitting diodes (LEDs) with different wavelengths: 380-750 nm (white), 620-750 nm (red) and 450-495 nm (blue). The maximum specific growth rate was obtained by N. oleoabundans with white LEDs (0.264 +/- 0.005 d(-1)), whereas the maximum biomass productivity (14 +/- 4 mg(dw) L-1 d(-1)) and CO2 fixation rate (11.4 mg(CO2) L-1 d(-1)) were obtained by C. vulgaris (also with white LEDs). Nitrogen and phosphorus removal efficiencies obtained under white light conditions were also the highest for the three studied microalgae

    Phenolic acids in the wild mushroom Ganoderma lucidum and synthesis of some possible metabolites.

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    Ganoderma lucidum is one of the most extensive!) studied mushrooms due to its medicinal properties, p-Hydroxybenzoic acid was the most abundant phenolic acid found in this mushroom. after HPLC-DAD-MS analysis. In the present work we describe the synthesis of glucuronide and methyl derivatives of p-hydroxybenzoic acid, which arc two of the main circulating metabolites found in humans. Their biological activity is going to be evaluated and compared to the parent compound in order to understand the in vivo mechanism of action of phenolic acids, considering their metabolis

    Antimicrobial and demelanizing activity of Ganoderma lucidum extract, p-hydroxybenzoic and cinnamic acids and their synthetic acetylated glucuronide methyl esters

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    Mushroom extracts or isolated compounds may be useful in the search of new potent antimicrobial agents. Herein, it is described the synthesis of protected (acetylated) glucuronide derivatives of p-hydroxybenzoic and cinnamic acids, two compounds identified in the medicinal mushroom Ganoderma lucidum. Their antimicrobial and demelanizing activities were evaluated and compared to the parent acids and G. lucidum extract. p-Hydroxybenzoic and cinnamic acids, as also their protected glucuronide derivatives revealed high antimicrobial (antibacterial and antifungal) activity, even better than the one showed by commercial standards. Despite the variation in the order of parent acids and the protected glucuronide derivatives, their antimicrobial activity was always higher than the one revealed by the extract. Nevertheless, the extract was the only one with demelanizing activity against A. niger. The acetylated glucuronide derivatives could be deprotected to obtain glucuronide metabolites, which circulate in the human organism as products of the metabolism of the parent compounds.Fundação para a Ciência e a Tecnologia (FCT, Portugal) for financial support to the Portuguese NMR network and to FCT and FEDER-COMPETE/QREN/EU for the financial support through the research project PTDC/AGR-ALI/110062/2009 and the research centres (PEst-C/QUI/UI0686/2011 and PEst-OE/AGR/UI0690/2011). S.A. Heleno (BD/70304/2010) also thanks FCT, POPH-QREN and FSE. The authors also thank to Serbian Ministry of Education and Science (grant number 173032) for financial support

    Kinetics of Eucalypt Lignosulfonate Oxidation to Aromatic Aldehydes by Oxygen in Alkaline Medium

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    The oxidation kinetics of lignosulfonates (LS) from acidic magnesium-based sulfite pulping of Eucalyptus globulus wood with oxygen under alkaline conditions was studied. The analysis of oxidation products in the reaction system O(2)/NaOH revealed a predominance of aromatic aldehydes (vanillin and syringic aldehyde) though small amounts of vanillic and syringic acids and acetophenone/phenylacetaldehyde derivatives have also been detected. The rate constant of syringic aldehyde formation was roughly twice of that for vanillin. The effective activation energies for the oxidation of LS to aromatic aldehydes (ca. 60-70 kJ/mol) were rather different to those found for the formation of aromatic acids (ca. 110 kJ/mol) indicating different mechanisms involved in the rate-determining reaction step. The addition of catalyst (copper salt, 20% w/w) promoted the LS oxidation with increments of aromatic aldehyde yields by 25-50%. The maximum yields of syringic aldehyde and vanillin upon LS oxidation were 16.1 and 4.5%, respectively (150 degrees C, 20 min, P(O2) = 10 bar, 0.9 M NaOH solution). The highly negative effect of concomitant sugars in sulfite liquor to the yield of aromatic aldehydes was highlighted

    Unnatural benz-X-azolyl asparagine derivatives as novel fluorescent amino acids : synthesis and photophysical characterization

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    A family of new asparagine derivatives bearing benzothiazole and benzimidazole units, functionalised with electron donor or acceptor groups, were synthesized in good to excellent yields. The photophysical characterization of these new heterocyclic amino acids was performed by UV-visible absorption and fluorescence emission studies and revealed that the compounds displayed remarkably high fluorescence quantum yields and Stokes’ shifts, making them good candidates for application as fluorescent probes by incorporation into peptidic frameworks.Fundação para a Ciência e a Tecnologia (FCT

    Synthesis of novel Glycoconjugates derived from Alkynyl heterocycles through a click approach

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    Accepted author version posted online: 05 Jun 2012The synthesis of a series of novel 1,4-disubstituted 1,2,3-triazole compounds bearing a D-glucose derivative and an heteroaromatic system is described. Alkylation of isatin, 3-methyl-carbazole and one tetrahydro-gamma-carboline with propargyl bromide gave their N-propargyl derivatives in good yields. These compounds further reacted with acetylated D-glucose with the azide group in position 1, to give three final products and with peracetylated 6-azido-6-deoxy-alpha-D-methylglucoside giving the corresponding derivative of tetrahydro-gamma-carboline.FCT (Fundação para a Ciência e Tecnologia) and FEDE

    Physicochemical characterization of psyllium fiber

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    Psyllium is the common name used for several members of the plant genus Plantago, whose seeds are commercially used for mucilage production. Owing to its considerable fiber amount it has been used as dietary fiber supplement. Psyllium has a strong gelling ability, even at low temperature, enabling its use as a gelling agent in the food industry. This work is part of a project to developing jellies enriched with fiber, honey and propolis, aiming to increase these products intake, with evident health benefits. The chemical characterization of psyllium was performed, with the following results (in dry matter): total ash 2.5%, fat content 3.4% and total protein 1.4%. After qualitative acid hydrolysis polymeric sugars were quantified (in dry matter): glucan 7.3%, xylan 61.1% and arabinan 22.9%. This means that total fiber content is about 90%, being soluble fiber predominant, and allows classifying psyllium hemicellulose as an arabinoxylan. Psyllium functional properties were evaluated by water-binding capacity and swelling determination: 27.1 g/g and 36.9 ml/g, respectively. These properties are important in the food industry, but under certain circumstances may limit the food type that can be enriched with this fiber. An important part of the research consisted on the characterization of gels viscoelastic behavior and texture, which were prepared with different psyllium particle dimension (raw and ground) and concentration (2.0%, 2.5% and 3.0%). The Response Surface Methodology was used to study the effect of process conditions (time and temperature) on texture and color characteristics of gels. Texture properties of gels were evaluated by Texture Profile Analysis. Gels dynamic behaviour was studied by a sequence of oscillatory measurements of temperature, time and frequency sweeps. Psyllium gelling properties were improved with the reduction of the fiber particle dimension. Gels revealed potential viscoelastic properties that might be interesting in the industrial purpose of honey jelly production

    Cytotoxicity of Coprinopsis atramentaria extract, organic acids and their synthesized methylated and glucuronate derivatives

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    Coprinopsis atramentaria is a wild edible mushroom whose methanolic extract revealed a marked antioxidant activity; p-hydroxybenzoic (HA), p-coumaric (CoA) and cinnamic (CA) acids were identified in the extract. In the present work, the cytotoxicity of C. atramentaria extract, previously identified organic acids and their synthesized derivatives (methylated compounds and protected glucuronides) was evaluated. Among all the tested cell lines (MCF-7—breast adenocarcinoma, NCI-H460—non-small cell lung carcinoma, HCT15—colon carcinoma, HeLa—cervical carcinoma and HepG2—hepatocellular carcinoma), the extract presented good activity for the first three cell lines mentioned; in most of the cases methylated and glucuronide derivatives showed a higher activity than the corresponding parental compounds. The substitution of the carboxylic group (in parental organic acids) for an ester (in methylated derivatives) increased the cytotoxicity for tumor cell lines. Acetylated glucuronide derivatives showed higher cytotoxicity when compared with the corresponding parental acids

    Burnout syndrome and coping strategies in Portuguese oncology health care providers

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    Background Burnout is a multidimensional syndrome and includes symptoms of emotional exhaustion, depersonalization, and reduced personal accomplishment at work. Oncology health care providers are at high risk to develop symptoms of burnout because of work-related stressors. Adaptive coping strategies adopted to deal with stressors may prevent the development of burnout. Objective The present study aims to assess the association between burnout, functional coping strategies, and occupational factors in a sample of oncology providers, mostly nurses. Methods Sociodemographic Questionnaire, the Maslach Burnout Inventory, and the Problem Solving Inventory “Inventário de Resolução de Problemas” were administered. Descriptive, correlational, and linear regression analyses were performed. Results The study showed that emotional exhaustion correlated with lower levels of adaptive coping, less years of experience in Oncology, and a greater amount of hours worked per week. Personal accomplishment was associated with the adaptive coping strategies. No further statistically significant associations were identified. Discussion Our findings support the importance of adaptive coping strategies in order to prevent symptoms of burnout when health professionals face potentially stressful occupational factors. Training aimed at improving adaptive coping skills may prevent burnout syndrome for health care professionals working in Oncology

    Unveiling biological activities of marine fungi: the effect of sea salt

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    There is an urgent need for new substances to overcome current challenges in the health sciences. Marine fungi are known producers of numerous compounds, but the manipulation of growth conditions for optimal compound production can be laborious and time-consuming. In Portugal, despite its very long coastline, there are only a few studies on marine fungi. From a collection of Portuguese marine fungi, we screened for antimicrobial, antioxidant, enzymatic, and cytotoxic activities. Mycelia aqueous extracts, obtained by high pressure-assisted extraction, and methanolic extracts of culture media showed high antioxidant, antimicrobial, and cytotoxic activities. The mycelium extracts of Cladosporium rubrum showed higher antioxidant potential compared to extracts from other fungi. Mycelia and culture media extracts of Aspergillus affinis and Penicillium lusitanum inhibited the growth of Staphylococcus aureus, Kocuria rhizophila, Enterococcus faecalis, Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa, including multiresistant strains. Penicillium lusitanum and Trichoderma aestuarinum inhibited the growth of clinical strains of Candida albicans, C. glabrata, C. parapsilosis, and C. tropicalis. All extracts from culture media were cytotoxic to Vero cells. Sea salt induced alterations in the mycelium's chemical composition, leading to different activity profiles.info:eu-repo/semantics/publishedVersio
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