526 research outputs found

    Valorisation of red beet waste: one-step extraction and separation of betalains and chlorophylls using thermoreversible aqueous biphasic systems

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    Globally, up to 50% of root crops, fruits and vegetables produced is wasted. Beetroot stems and leaves fit into this scenario, with only a small fraction being used in cattle food. One way of approaching this problem is through their valorisation, by extracting and recovering valuable compounds present in this type of waste that could be used in other applications, while contributing towards a circular economy. In this work, a new integrated process using thermoreversible aqueous biphasic systems (ABS) composed of quaternary ammonium-based ionic liquids (ILs) and polypropyleneglycol 400 g mol−1 (PPG) is shown to allow the one-step extraction and separation of two pigment classes—betalains and chlorophylls—from red beet stems and leaves. The pigment extraction was carried out with a monophasic aqueous solution of the IL and PPG, whose phase separation was then achieved by a temperature switch, resulting in the simultaneous separation of chlorophylls and betalains into opposite phases. A central composite design was used to optimise the extraction parameters (time, temperature, and solid : liquid (S/L) ratio) of both pigment extraction yields, reaching at 20 °C, 70 min and a S/L ratio of 0.12 a maximum extraction yield of 6.67 wt% for betalains and 1.82 wt% for chlorophylls (per weight of biomass). Moreover, it is shown that aqueous solutions of ILs better stabilise betalains than the gold standard solvent used for the extraction method. Among the studied systems, the ABS comprising the IL N-ethyl-N-methyl-N,N-bis(2-hydroxyethyl) bromide ([N21(2OH)(2OH)]Br) presented the best separation performance, with an extraction efficiency of 92% and 95% for chlorophylls and betalains, respectively, for opposite phases. The pigments were removed from the respective phases using affinity resins, with high recoveries: 96% for betalains and 98% for chlorophylls, further allowing the IL reuse. Finally, the cyto- and ecotoxicities of the quaternary ammonium-based ILs were determined. The obtained results disclosed low to negligible toxicity in the thousands of mg L−1 range, with [N21(2OH)(2OH)]Br being harmless from an ecotoxicological point of view. Overall, it is shown here that the developed process is an innovative approach for the one-step extraction and selective separation of pigments contributing to the valorisation of waste biomass

    Use of construction and demolition recycled materials (C&Drm) in road pavements validated on experimental test sections

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    The construction activity usually generates large amounts of waste from different sources and processes. Due to the increasing shortage of space for landfill implementation and the costs associated with waste control regulations, derived from its ever increasing environmental protection requirements, the most desirable alternative is the reduction of construction and demolition waste volumes by means of their reuse and recycling. A research project, SUPREMA - Sustainable Application of Construction and Demolition Recycled Materials (C&DRM) in Road Infrastructures, is being developed by the National Laboratory for Civil Engineering (LNEC), and by the University of Lisbon (IST). This project seeks to contribute to the sustainable implementation of C&DRM in road pavements by improving the knowledge of the physical, mechanical and environmental behaviour of these materials when placed as aggregates in unbound pavement layers. Besides a general presentation of the research project and the construction procedures of a test pit structure where four different materials were applied, this paper presents some results related to the characteristics of the studied materials, supported by laboratory and by in situ tests performed with the FWD in the test pit structure. It was concluded that all materials demonstrate an acceptable structural performance

    CONSULTA DE ENFERMAGEM NO AMBULATÓRIO DE HIV/AIDS: A PERCEPÇÃO DOS USUÁRIOS

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    O estudo busca analisar como a consulta de enfermagem é percebida pelos usuários de um ambulatório especializado em Vírus da Imunodeficiência Humana/Síndrome da Imunodeficiência Adquirida (HIV/AIDS) no município de Fortaleza-CE. Trata-se de um estudo exploratório e descritivo, com abordagem qualitativa. Os dados foram coletados através de entrevista semiestruturada com quinze usuários da referida instituição e analisados com o suporte da análise de conteúdo. A consulta de enfermagem foi relatada pelos usuários como um momento de aprendizado, centrado no fornecimento de informações. A confiança e o apoio emocional estabelecido pelo profissional atuam como um suporte frente aos conflitos vivenciados pelo paciente, possibilitando a construção de um novo olhar frente à doença. Acreditamos que a realização da consulta de enfermagem em uma perspectiva dialogal poderá proporcionar aos sujeitos a ressignificação dos conflitos que permeiam o seu adoecimento

    Student responses to the introduction of case-based learning and practical activities into a theoretical obstetrics and gynaecology teaching programme

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    BACKGROUND: The fourth-year Obstetrics and Gynaecology course at our institution had previously been taught using theory classes alone. A new teaching model was introduced to provide a better link with professional practice. We wished to evaluate the impact of the introduction of case discussions and other practical activities upon students' perceptions of the learning process. METHODS: Small-group discussions of cases and practical activities were introduced for the teaching of a fourth-year class in 2003 (Group II; 113 students). Comparisons were made with the fourth-year class of 2002 (Group I; 108 students), from before the new programme was introduced. Students were asked to rate their satisfaction with various elements of the teaching programme. Statistical differences in their ratings were analysed using the chi-square and Bonferroni tests. RESULTS: Group II gave higher ratings to the clarity of theory classes and lecturers' teaching abilities (p < 0.05) and lecturers' punctuality (p < 0.001) than did Group I. Group II had greater belief that the knowledge assessment tests were useful (p < 0.001) and that their understanding of the subject was good (p < 0.001) than did Group I. Group II gave a higher overall rating to the course (p < 0.05) than did Group I. However, there was no difference in the groups' assessments of the use made of the timetabled hours available for the subject or lecturers' concern for students' learning. CONCLUSIONS: Students were very receptive to the new teaching model

    Genetic Characterization of Venezuelan Equine Encephalitis Virus from Bolivia, Ecuador and Peru: Identification of a New Subtype ID Lineage

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    Venezuelan equine encephalitis virus (VEEV) has been responsible for hundreds of thousands of human and equine cases of severe disease in the Americas. A passive surveillance study was conducted in Peru, Bolivia and Ecuador to determine the arboviral etiology of febrile illness. Patients with suspected viral-associated, acute, undifferentiated febrile illness of <7 days duration were enrolled in the study and blood samples were obtained from each patient and assayed by virus isolation. Demographic and clinical information from each patient was also obtained at the time of voluntary enrollment. In 2005–2007, cases of Venezuelan equine encephalitis (VEE) were diagnosed for the first time in residents of Bolivia; the patients did not report traveling, suggesting endemic circulation of VEEV in Bolivia. In 2001 and 2003, VEE cases were also identified in Ecuador. Since 1993, VEEV has been continuously isolated from patients in Loreto, Peru, and more recently (2005), in Madre de Dios, Peru. We performed phylogenetic analyses with VEEV from Bolivia, Ecuador and Peru and compared their relationships to strains from other parts of South America. We found that VEEV subtype ID Panama/Peru genotype is the predominant one circulating in Peru. We also demonstrated that VEEV subtype ID strains circulating in Ecuador belong to the Colombia/Venezuela genotype and VEEV from Madre de Dios, Peru and Cochabamba, Bolivia belong to a new ID genotype. In summary, we identified a new major lineage of enzootic VEEV subtype ID, information that could aid in the understanding of the emergence and evolution of VEEV in South America
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