On the solubility of three disperse anthraquinone dyes in supercritical carbon dioxide: new experimental data and correlation

Solubility measurements of quinizarin. (1,4-dihydroxyanthraquinone), disperse red 9 (1-(methylamino) anthraquinone), and disperse blue 14 (1,4-bis(methylamino)anthraquinone) in supercritical carbon dioxide (SC CO2) were carried out in a flow type apparatus, at a temperature range from (333.2 to 393.2) K and at pressures from (12.0 to 40.0) MPa. Mole fraction solubility of the three dyes decreases in the order quinizarin (2.9 x 10(-6) to 2.9.10(-4)), red 9 (1.4 x 10(-6) to 3.2 x 10(-4)), and blue 14 (7.8 x 10(-8) to 2.2 x 10(-5)). Four semiempirical density based models were used to correlatethe solubility of the dyes in the SC CO2. From the correlation results, the total heat of reaction, heat of vaporization plus the heat of solvation of the solute, were calculated and compared with the results presented in the literature. The solubilities of the three dyes were correlated also applying the Soave-Redlich-Kwong cubic equation of state (SRK CEoS) with classical mixing rules, and the physical properties required for the modeling were estimated and reported

Herbicidal activity of volatiles from coriander, winter savory, cotton lavender, and thyme isolated by hydrodistillation and supercritical fluid extraction

The volatiles from Coriandrum sativum L., Satureja montana L., Santolina chamaecyparissus L., and Thymus vulgaris L. were isolated by hydrodistillation (essential oil) and supercritical fluid extraction (volatile oil). Their effect on seed germination and root and shoot growth of the surviving seedlings of four crops (Zea mays L., Triticum durum L., Pisum sativum L., and Lactuca sativa L.) and two weeds (Portulaca oleracea L. and Vicia sativa L.) was investigated and compared with those of two synthetic herbicides, Agrocide and Prowl. The volatile oils of thyme and cotton lavender seemed to be promising alternatives to the synthetic herbicides because they were the least injurious to the crop species. The essential oil of winter savory, on the other hand, affected both crop and weeds and can be appropriate for uncultivated fields

Supercritical Extraction of Lycopene from Tomato Industrial Waste with Ethane

Supercritical fluid extraction of all-E-lycopene from tomato industrial wastes (mixture of skins and seeds) was carried out in a semi-continuous flow apparatus using ethane as supercritical solvent. The effect of pressure, temperature, feed particle size, solvent superficial velocity and matrix initial composition was evaluated. Moreover, the yield of the extraction was compared with that obtained with other supercritical solvents (supercritical CO2 and a near critical mixture of ethane and propane). The recovery of all-E-lycopene increased with pressure, decreased with the increase of the particle size in the initial stages of the extraction and was not practically affected by the solvent superficial velocity. The effect of the temperature was more complex. When the temperature increased from 40 to 60 °C the recovery of all-E-lycopene increased from 80 to 90%. However, for a further increase to 80 °C, the recovery remained almost the same, indicating that some E-Z isomerization could have occurred, as well as some degradation of lycopene. The recovery of all-E-lycopene was almost the same for feed samples with different all-E-lycopene content. Furthermore, when a batch with a higher all-E-lycopene content was used, supercritical ethane and a near critical mixture of ethane and propane showed to be better solvents than supercritical CO2 leading to a faster extraction with a higher recovery of the carotenoid

Composition and antioxidant activity of thymus vulgaris volatiles: comparison between supercritical fluid extraction and hydrodistillation

Supercritical fluid extraction (SEE) of the volatile oil from Thymus vulgaris L. aerial flowering parts was performed under different conditions of pressure, temperature, mean particle size and CO2 flow rate and the correspondent yield and composition were compared with those of the essential oil isolated by hydrodistillation (HD). Both the oils were analyzed by GC and GC-MS and 52 components were identified. The main volatile components obtained were p-cymene (10.0-42.6% for SFE and 28.9-34.8% for HD), gamma-terpinene (0.8-6.9% for SFE and 5.1-7.0% for HD), linalool (2.3-5.3% for SFE and 2.8-3.1% for HD), thymol (19.5-40.8% for SFE and 35.4-41.6% for HD), and carvacrol (1.4-3.1% for SFE and 2.6-3.1% for HD). The main difference was found to be the relative percentage of thymoquinone (not found in the essential oil) and carvacryl methyl ether (1.0-1.2% for HD versus t-0.4 for SFE) which can explain the higher antioxidant activity, assessed by Rancimat test, of the SFE volatiles when compared with HD. Thymoquinone is considered a strong antioxidant compound

Exploring Scenedesmus obliquus and nannochloropsis sp. potential as a sustianable raw material for biofuels amd high added value compounds

In this work, the authors propose a microalga-based integrated system, where optimization of several energy vectors (biodiesel, bioethanol and bioH2) is highlighted under the concept of biorefinery (Project PTDC/AAC-AMB/100354/2008). This involves the integration of different processes such as oil and sugar extraction from microalgae for biodiesel and bioethanol production respectively, and bioH2 production from the whole and/or biomass leftovers. The extraction of high value added compounds, such as carotenoids, contributes to the economic viability of the overall process

A biorefinery from Nannochloropsis sp. microalga – Energy and CO2 emission and economic analyses

Are microalgae a potential energy source for biofuel production? This paper presents the laboratory results from a Nannochloropsis sp. microalga biorefinery for the production of oil, high-value pigments, and biohydrogen (bioH2). The energy consumption and CO2 emissions involved in the whole process (microalgae cultivation, harvest, dewater, mill, extraction and leftover biomass fermentation) were evaluated. An economic evaluation was also performed. Oil was obtained by soxhlet (SE) and supercritical fluid extraction (SFE). The bioH2 was produced by fermentation of the leftover biomass. The oil production pathway by SE shows the lowest value of energy consumption, 177-245 MJ/MJprod, and CO2 emissions, 13–15 kgCO2/MJprod. Despite consuming and emitting c.a. 20% more than the SE pathway, the oil obtained by SFE, proved to be more economically viable, with a cost of 365€/kgoil produced and simultaneously extracting high-value pigments. The bioH2 as co-product may be advantageous in terms of product yield or profit

Phytochemical Characterization and Biological Evaluation of the Aqueous and Supercritical Fluid Extracts from Salvia sclareoides Brot

Plants belonging to the genus Salvia (Lamiaceae) are known to have a wide range of biological properties. In this work, extracts obtained from the aerial parts of Salvia sclareoides Brot. were evaluated to investigate their chemical composition, toxicity, bioactivity, and stability under in vitro gastrointestinal conditions. The composition of the supercritical fluid extract was determined by GC and GC-MS, while the identification of the infusion constituents was performed by HPLC-DAD and LC-MS. The in vitro cytotoxicity of both extracts (0-2 mg/mL) was evaluated in Caco-2 cell lines by the MTT assay. The anti-inflammatory and anticholinesterase activities were determined through the inhibition of cyclooxygenase-1 and acetylcholinesterase enzymes, while β-carotene/linoleic acid bleaching test and the DPPH assays were used to evaluate the antioxidant activity. The infusion inhibited cyclooxygenase-1 (IC50 = 271.0 μg/mL), and acetylcholinesterase (IC50 = 487.7 μg/ mL) enzymes, also demonstrated significant antioxidant properties, as evaluated by the DPPH (IC50 = 10.4 μg/mL) and β-carotene/linoleic acid (IC50 = 30.0 μg/mL) assays. No remarkable alterations in the composition or in the bioactivities of the infusion were observed after in vitro digestion, which supports the potential of S. sclareoides as a source of bioactive ingredients with neuroprotective, anti-inflammatory and antioxidant properties.This work was supported by Fundação para a Ciência e a Tecnologia (FCT), Project UID/MULTI/00612/2013 and UID/QUI/50006/2013. FCT is also acknowledged for PJAM post-doctoral fellowship (SFRH/BPD/86948/2012) and for CG FCT Investigator (IF/01332/2014). The European Commission is also acknowledged for approval of the INOVAFUNAGEING commitment and the support of the projects PERSSILAA-FP7-ICT-2013-10, Project Nr. 610359, and D3i4AD, FP7-PEOPLE-2013-IAPP, GA 612347. The authors also gratefully acknowledge the collaboration of Prof. Ana Cristina Figueiredo (DBV-FCUL), for GC and GC-MS analysis, and of Prof. Maria Helena Florêncio (DQB-FCUL) for LC-MS support.info:eu-repo/semantics/publishedVersio

Sistema de autovigilância para deteção de alterações de lesões cutâneas pigmentadas

Melanoma is one of the most common skin cancers. Five per cent of all cancer cases that occur in a year are cases of melanoma, and many people die each year by melanoma because of overdue recognition. Moreover, the number of new cases of melanoma has been increasing in the last 30 years. Fortunately, melanoma is highly curable if detected yearly. To help mitigate this problem, the creation of applications capable of helping the user detect changes in skin moles and seek professional opinions, are instrumental. This dissertation aims at the development of an automated self-surveillance system focused on detecting changes in pigmented skin lesions over time. Quantitative analysis based on the ABCD-rule is applied to detect changes between a baseline and a follow-up image in terms of shape, colour and size. Image similarity measures for comparative evaluation of pair-images are also considered, providing information about new attributes such as colours patterns and texture. Finally, the feasibility of integrating these complementary criteria into a mobile application is evaluated. The application is designed to help scan, track and monitor pigmented skin lesions, allowing the user to compare images taken over time.Melanoma é um dos tipos de pele cancro mais comum. Cinco por cento de todos os casos de cancro anuais são identificados como melanoma e em muitos casos, o paciente morre devido a um diagnóstico tardio. Ademais, o número de casos de melanoma tem vindo a aumentar nos últimos 30 anos. Felizmente, melanoma tem uma taxa de cura extremamente alta se detetado antecipadamente. Portanto, para ajudar a mitigar este problema, a criação de aplicações capazes de ajudar o utilizador a detetar mudanças em lesões cutâneas, e consequentemente procurar uma opinião profissional, são extremamente uteis. Esta tese tem como objetivo o desenvolvimento de um sistema automático de auto-vigilância focado na deteção de mudanças em lesões cutâneas ao longo do tempo. Analise quantitativa com base na regra ABCD é aplicada de forma a detetar mudanças entre uma imagem base e uma imagem mais recente em termos de forma, cor e tamanho. Medidas de similaridade entre imagens para a comparação de pares de imagens também foram consideradas, dispondo informação acerca de novos atributos, como cor, padrões e textura. Finalmente, os algoritmos desenvolvidos foram implementados numa aplicação móvel de maneira a avaliar a sua viabilidade num dispositivo móvel. A aplicação foi desenhada de maneira a examinar, localizar e monitorizar uma lesão cutânea pigmantada, podendo assim o utilizador comparar images ao longo do tempo.Mestrado em Engenharia de Computadores e Telemátic

Modeling of the Kinetics of Supercritical Fluid Extraction of Lipids from Microalgae with Emphasis on Extract Desorption

Microalgae contain valuable biologically active lipophilic substances such as omega-3 fatty acids and carotenoids. In contrast to the recovery of vegetable oils from seeds, where the extraction with supercritical CO2 is used as a mild and selective method, economically viable application of this method on similarly soluble oils from microalgae requires, in most cases, much higher pressure. This paper presents and verifies hypothesis that this difference is caused by high adsorption capacity of microalgae. Under the pressures usually applied in supercritical fluid extraction from plants, microalgae bind a large fraction of the extracted oil, while under extremely high CO2 pressures their adsorption capacity diminishes and the extraction rate depends on oil solubility in supercritical CO2. A mathematical model for the extraction from microalgae was derived and applied to literature data on the extraction kinetics in order to determine model parameters