Supercritical extraction of polyphenols from different vegetable matrices and their retention and recovery using molecularly imprinted polymers

Dupla diplomação com a UNIFACS - Universidade SalvadorDifferent kinds of vegetable residues abundant in Trás-os-Montes region, namely walnut leaf, walnut shell, almond shell, grape marc, olive leaf and onion shell (a worldwide available biomass) were considered as possible sources of polyphenols. Extraction with supercritical carbon dioxide (at T=40 °C, P=160 bar and ethanol as co-solvent), ultrasound extraction and Soxhlet extraction were alternatively used to obtain mixtures containing these bioactive compounds. Aiming at the subsequent separation and concentration of the polyphenols from the complex extracts obtained, molecularly imprinted polymers (MIPs) were used as a kind of engineered adsorbents. MIP particles synthesized by precipitation polymerization with 4-vinylpyridine (4-VP) as functional monomer and quercetin as template were applied in the retention and recovery of the polyphenols. Comparative studies with commercial polymeric adsorbents (namely with the resin DAX8) were also performed. Batch adsorption, solid phase extraction (SPE) and operation in HPLC columns packed with the adsorbents were considered in these uptake/release studies. The identification and quantification of polyphenols was performed using Liquid Chromatography with Mass Spectroscopy and Diode Array Detector (LC-MS-DAD) and also with the more straightforward HPLC-DAD technique. With the supercritical CO2 (SCCO2) extraction conditions used, the richest phenolic profiles were obtained with onion shell and almond shell. Indeed, quercetin and many quercetin analogues (e.g. quercetin-O-glucoside, quercetin-O-diglycoside, quercetin dimer-O-hexoside, etc) were identified in these onion shell extracts, while quercetin, isorhamnetin-3-O-rutinoside or catechin (e.g.) were identified in the almond shell extracts. However, in spite of a similar composition, a higher phenolic content was measured for extracts obtained with the ultrasounds (US) or Soxhlet (SHOX) extraction, comparatively to supercritical CO2 extraction (e.g. around 10 mg/g of total phenolic compounds with US and SHOX extraction and 1 mg/g with SCCO2 for onion shell extracts, in a dry basis of plant residue). Benefits of molecular imprinting in the designing of tailored adsorbents to be used with downstream processing of polyphenols were evidenced in this research. Indeed, a very high polyphenol retention was here shown to be possible with MIPs, even when solvents with low water content are used (e.g. ethanol/water 80/20). Thus, the hydrophobic interactions, that usually is the main driving force for adsorption with common synthetic resins, is not the unique mechanism allowing the retention of these bioactive compounds in the synthesized molecularly imprinted polymer networks. The functionalization of the materials (here with pyridyl functional groups) and the creation of imprinted tailor-made cavities (promoting analogue mechanisms to antigen/antibody or substrate/enzyme binding) were congenial for the improved performance of the MIPs. Additionally, the manipulation of the particles morphology (through precipitation polymerization), allowing a facile binding accessibility (e.g. due to surface imprinting) should also contribute for the observed superior performance of the MIPs in polyphenols retention. The distinctive features of the MIP adsorbents were here demonstrated through the direct processing of plant extracts without water addition (e.g. using an ethanol/water 80/20 onion shell extract). A polyphenol-enriched fraction, containing quercetin and analogue molecules, was recovered at the end with the minimization of thermal treatments (only alcohol evaporation is needed if a dry residue is wanted). Thus, the simplification of the adsorption/desorption process was achieved and energetic costs can also be cut down (besides the minimization of the possible thermal degradation of the bioactive compounds). Summing up, this research demonstrate that MIP adsorbents can be helpful in the design of new and more flexible adsorption processes (e.g. working with a wider range of water content), aiming at the valorization of polyphenols present in plant extracts. Food industry, pharmaceutics and cosmetics are examples of applications fields for the principles here outlined.Diferentes tipos de resíduos vegetais abundantes na região de Trás-os-montes, como a folha de nogueira, a casca de noz, a casca de amêndoa, o bagaço da uva, a folha de oliveira e a casca da cebola (uma biomassa disponível de forma mais abrangente no planeta) foram considerados como possíveis fontes de polifenóis. A extração com dióxido de carbono supercrítico (usando T = 40 °C, P = 160 bar e etanol como co-solvente), a extração por ultrassom e a extração por Soxhlet foram alternativamente utilizadas para obter misturas contendo esses compostos bioativos. Visando a subsequente separação e concentração dos polifenóis dos extratos complexos obtidos, polímeros molecularmente impressos (MIPs) foram utilizados como uma espécie de adsorventes. Partículas de MIPs sintetizadas através de polimerização por precipitação com 4-vinilpiridina (4-VP) como monômero funcional e quercetina como molécula modelo foram aplicadas na retenção e recuperação dos polifenóis. Também foram realizados estudos comparativos com adsorventes poliméricos comerciais (como a resina DAX-8). A adsorção em batch, a extração em fase sólida (SPE) e a operação em colunas de HPLC empacotadas com os adsorventes foram consideradas neste estudo para a retenção e libertação dos compostos fenólicos. A identificação e quantificação de polifenóis foi realizada utilizando cromatografia líquida com espectroscopia de massa e detector de diodo array (LC-MS-DAD) e também com a técnica mais direta de HPLC-DAD. Com as condições de extração com CO2 supercrítico (SCCO2) utilizadas, os perfis fenólicos mais ricos foram obtidos com a casca da cebola e a casca de amêndoa. Foram identificadas quercetina e muitos análogos de quercetina (por exemplo, quercetina-o-glucosídeo, quercetina-o-diglicosídeo, quercetina dimer-o-hexoside, etc.) nos extratos da casca da cebola, enquanto quercetina, isorhamnetin-3-O-rutinoside ou catequina, por exemplo, foram identificados nos extratos da casca de amêndoa. No entanto, apesar de uma composição semelhante, um maior teor de compostos fenólicos foi medido para extratos obtidos com a extração por ultrassom (US) e Soxhlet (SHOX), comparativamente a extração com CO2 supercrítico (por exemplo, cerca de 10 mg/g de compostos fenólicos totais com as extrações US e SHOX e 1 mg/g com SCCO2 para extratos de casca de cebola, numa base seca de resíduo vegetal). Os benefícios da impressão molecular na concepção de adsorventes adaptados a serem utilizados com o processamento a jusante de polifenóis foram evidenciados nestapesquisa. De fato, foi possível mostrar uma elevada retenção de polifenóis com MIPs, mesmo quando solventes com baixo teor de água são utilizados (por exemplo, etanol/água 80/20). Assim, as interações hidrofóbicas, que geralmente são a principal força motriz para a adsorção com resinas sintéticas comuns, não é o único mecanismo que permite a retenção desses compostos bioativos nas redes de polímeros sintetizados com a técnica de impressão molecular. A funcionalização dos materiais (com grupos funcionais piridil) e a criação de cavidades impressas por medida (promovendo mecanismos análogos à interação antígeno/anticorpo ou substrato/enzima) foram benéficas para o melhor desempenho dos MIPs. Adicionalmente, a manipulação da morfologia das partículas (através da polimerização por precipitação), permitiu uma fácil acessibilidade aos sítios de adsorção (por exemplo, devido à impressão à superfície) que deve igualmente contribuir para o desempenho superior observado com os MIPs na retenção de polifenóis. As características distintivas dos MIPs como adsorventes foram aqui demonstradas através do processamento direto de extratos de plantas sem adição de água (por exemplo, usando um extrato da casca da cebola em etanol/água 80/20). Uma fração enriquecida com polifenóis, contendo quercetina e moléculas análogas, foi recuperada no final com a minimização dos tratamentos térmicos (somente a evaporação do álcool é necessária se um resíduo seco for pretendido). Assim, a simplificação do processo de adsorção/dessorção foi alcançada, e os custos energéticos também poderão ser potencialmente reduzidos (para além da minimização de uma possível degradação térmica dos compostos bioativos). Resumindo, esta pesquisa demonstra que os MIPs como adsorventes podem ser úteis na concepção de novos processos de adsorção e mais flexíveis (por exemplo, permitindo trabalhar com uma quantidade de água mais ampla relativamente aos adsorventes comuns), visando a valorização dos polifenóis presentes nos extratos vegetais. A indústria alimentícia, farmacêutica e cosmética são exemplos de campos de aplicações para os princípios aqui delineados.This work was supported by the project “AIProcMat@N2020—Advanced Industrial Processes and Materials for a Sustainable Northern Region of Portugal 2020”, with the reference NORTE-01-0145-FEDER-000006, supported by Norte Portugal Regional Operational Programa (NORTE 2020), under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (ERDF) and of Project POCI-01-0145-FEDER-006984—Associate Laboratory LSRE-LCM funded by ERDF through COMPETE2020— Programa Operacional Competitividade e Internacionalização (POCI)—and by national funds through FCT—Fundação para a Ciência e a Tecnologia

Preserving the Sea in a Radioactive World: How Japan\u27s Plan to Release Treated Nuclear Wastewater into Pacific Ocean Violates UNCLOS

On December 10, 1982, the 1973–1982 United Nations Convention on the Law of the Sea (UNCLOS III) concluded. Japan became a signatory to the Convention on February 7, 1983 and ratified the Convention on June 20, 1996. Subsequently, Japan became a party to the treaty and committed itself to abide by the United Nations Convention on the Law of the Sea (UNCLOS)

Learning Bayesian Networks for Student Modeling

In the last decade, there has been a growing interest in using Bayesian Networks (BN) in the student modelling problem. This increased interest is probably due to the fact that BNs provide a sound methodology for this difficult task. In order to develop a Bayesian student model, it is necessary to define the structure (nodes and links) and the parameters. Usually the structure can be elicited with the help of human experts (teachers), but the difficulty of the problem of parameter specification is widely recognized in this and other domains. In the work presented here we have performed a set of experiments to compare the performance of two Bayesian Student Models, whose parameters have been specified by experts and learnt from data respectively. Results show that both models are able to provide reasonable estimations for knowledge variables in the student model, in spite of the small size of the dataset available for learning the parametersUniversidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

ANÁLISIS DE LA ECONOMÍA FAMILIAR Y SU IMPACTO EN EL BIENESTAR FAMILIAR EN COMUNIDADES MIXTECAS DEL ESTADO DE OAXACA

En esta investigación nos dirigimos particularmente en el municipio de San Andrés Lagunas y su agencia San Isidro Lagunas en la mixteca del estado de Oaxaca, comunidades caracterizadas por su economía campesina puesto que las dos localidades realizan las mismas actividades como son la agricultura, cría de aves de traspatio, artesanías por mencionar algunas pero dichas ocupaciones no siempre son favorables porque normalmente son afectadas por el clima y actualmente las comunidades tienen más población de la tercera edad y son personas que no están aptas para realizar una actividad económica ya que su población joven es mínima, motivo por el cual se consideran las causas principales de un bajo nivel de bienestar familiar por lo tanto no tienen un amplia disposición de consumo; en el desarrollo de la investigación se analiza la economía familiar y su impacto en el bienestar de cada comunidad y de acuerdo a las encuestas aplicadas se obtuvieron datos gráficos en la que se consideran que las transferencias de gobierno tuvieron un efecto positivo en su bienestar, seguida de producción de aves de traspatio mismas que fueron analizadas para obtener un modelo económico

Fijación externa del húmero en aves rapaces : descripción de un caso clínico en un ejemplar de Ratonero común (Buteo buteo)

Un Ratonero común (Buteo buteo) fue intervenido quirúrgicamente de una fractura de húmero en su ala derecha. Mediante la colocación de un fijador externo le fue inmovilizada la fractura resultando una correcta formación del callo óseo y la recuperación total de la funcionalidad del ala.The surgical treatment of the humeral fracture in a buzzard (Buteo buteo) by means of external fixation is described. The fracture healed correctly and the wing recovered its normal functinability by the 51st day postop

Instability of shallow lakes : a matter of the complexity of factors involved in sediment and water interaction?

Instability and extreme fluctuations in water quality characterizing shallow lakes are to a large extent due to rapid changes in the internal supply rates of nutrients. In fact, is in these systems that sediment and water interaction plays a major role in nutrients' dynamics. For this study, a double-approach perspective with both field measurements and laboratory experiments has been used in order to determine the contribution of physical, biological, and chemical mechanisms to nutrients' dynamics in two shallow adjacent lakes in Andalusia (Spain). Despite their geographic proximity, strong differences between the study systems have been recognised. In the Lake Honda, the high nutrient concentrations, which ultimately support a large algal biomass, are the result of: i. Resuspension of the surface sediment favoured by its morphometry, hydrologic regime and sediment granulometry. ii. Intense organic matter mineralization due to the labile nature of the organic settled matter (planktonic). In Lake Nueva, by contrast, physical constrains (i.e. wind-induced resuspension) have a limited effect due to the coarse surface sediment and to the development of macrophytes (Najas marina, Potamogeton pectinatus). In addition, the structurally more complex organic matter of its sediment regulates the low nutrients turnover. In this lake, nutrient exchange rates across the sediment-water interface are also controlled by chemical processes, such as P adsorption onto CaCO3, a mechanism that is favoured by the high Ca+2 concentration in the interstitial water. In this way, the joint effect of physical, chemical, and biological mechanisms determine the fast nutrients' benthic regeneration in Lake Honda, while in contrast, a large fraction of the nutrients present in the sediment of the Lake Nueva is in particle form.La inestabilidad y las extremas fluctuaciones en la calidad del agua que caracterizan a los lagos someros, se deben en gran medida, a cambios rápidos en la carga interna de nutrientes. De hecho, es en éstos sistemas, donde la interacción agua-sedimento juega un papel esencial en la dinámica de los nutrientes. Para este estudio, se ha empleado una doble aproximación, basada tanto en datos de campo como en experimentos en laboratorio, para determinar la contribución de mecanismos físicos, químicos y biológicos a la dinámica de los nutrientes en dos lagunas costeras en Andalucía (España). A pesar de su proximidad geográfica, se han reconocido fuertes diferencias entre ambos sistemas. En la laguna Honda, las elevadas concentraciones de nutrientes, que en última instancia soportan una elevada biomasa algal, son el resultado de: i. Resuspensión del sedimento superficial, favorecida por la morfometría, el régimen hídrico y la granulometría de su sedimento. ii. Intensa mineralización de la materia orgánica debida al carácter lábil de la materia orgánica sedimentada (origen planctónico). En la laguna Nueva, por el contrario, el impacto de los factores físicos (p.e. resuspensión inducida por el viento) se encuentra limitado por la gruesa granulometría del sedimento superficial así como por el desarrollo de macrófitos (Najas marina, Potamogeton pectinatus). Más aún, la naturaleza estructuralmente más compleja de la materia orgánica presente en su sedimento determina unas menores tasas de regeneración de nutrientes. En esta laguna, las tasas de intercambio de nutrientes a través de la interfase agua-sedimento se encuentran, además, controladas por procesos químicos, tales como la precipitación de P sobre CaCO3, mecanismo que se encuentra favorecido por las elevadas concentraciones de Ca+2 presentes en el agua intersticial. Por tanto, es la conjunción de mecanismos físicos, químicos y biológicos los que determinan la rápida regeneración béntica de nutrientes en la laguna Honda; mientras que, por el contrario, una importante fracción de los nutrientes presentes en el sedimento de la laguna Nueva se encuentra en forma particulada

Encouraging Women Participation in Free and Open Source Software Organizations: The GNOME OPW Initiative

Even though the global demand for computing talent is surging, women’s representation in the computing profession has steadily declined. This phenomenon is not new and is present worldwide, not being associated with a particular country or culture. The reason of why women tend to avoid computing careers does not have a clear answer yet and is being researched by several organizations, institutions and companies. The GNOME Outreach Program for Women (OPW) internships has been inspired by this fact. Focused on the context of Free and Open Source Software (FOSS) organizations, the GNOME’s OPW is performing a great effort for the integration of women in this particular area of CS. This paper analyzes several issues on how can women be encouraged to participate in FOSS organizations, based on the experiences of a former GNOME OPW intern. In addition we discuss the role of different stakeholders (organizations, universities) in improving women participation in FOSS organizations in Argentina.Sociedad Argentina de Informática e Investigación Operativ

Encouraging Women Participation in Free and Open Source Software Organizations: The GNOME OPW Initiative

Even though the global demand for computing talent is surging, women’s representation in the computing profession has steadily declined. This phenomenon is not new and is present worldwide, not being associated with a particular country or culture. The reason of why women tend to avoid computing careers does not have a clear answer yet and is being researched by several organizations, institutions and companies. The GNOME Outreach Program for Women (OPW) internships has been inspired by this fact. Focused on the context of Free and Open Source Software (FOSS) organizations, the GNOME’s OPW is performing a great effort for the integration of women in this particular area of CS. This paper analyzes several issues on how can women be encouraged to participate in FOSS organizations, based on the experiences of a former GNOME OPW intern. In addition we discuss the role of different stakeholders (organizations, universities) in improving women participation in FOSS organizations in Argentina.Sociedad Argentina de Informática e Investigación Operativ

Encouraging Women Participation in Free and Open Source Software Organizations: The GNOME OPW Initiative

Even though the global demand for computing talent is surging, women’s representation in the computing profession has steadily declined. This phenomenon is not new and is present worldwide, not being associated with a particular country or culture. The reason of why women tend to avoid computing careers does not have a clear answer yet and is being researched by several organizations, institutions and companies. The GNOME Outreach Program for Women (OPW) internships has been inspired by this fact. Focused on the context of Free and Open Source Software (FOSS) organizations, the GNOME’s OPW is performing a great effort for the integration of women in this particular area of CS. This paper analyzes several issues on how can women be encouraged to participate in FOSS organizations, based on the experiences of a former GNOME OPW intern. In addition we discuss the role of different stakeholders (organizations, universities) in improving women participation in FOSS organizations in Argentina.Sociedad Argentina de Informática e Investigación Operativ