Influence of synthetic antioxidants on the oxidation stability of biodiesel produced from acid raw Jatropha curcas oil

In the present work,Jatropha curcas biodiesel was produced from a high free fatty acid raw oil (AV = 3536 mg KOH g(-1)) containing 76.5% w/w of unsaturated fatty acids. The production route consisted of a two-step method, using acid esterification, followed by conventional alkali methanolysis. Biodiesel was characterized in agreement with EN 14214:2014 and a study on the use of 4 synthetic antioxidants was conducted. The high free fatty acid content of the oil could be reduced to 0.8% w/w by add esterification. A good product quality was generally observed but the very low oxidation stability, corresponding to an induction period (IP) of 1.37 h, was the highest concern. Statistically significant predictive models, which related each antioxidant concentration with the IP, were obtained. Pyrogallol (PY) showed the best results, being estimated that the use of 204 ppm in biodiesel could increase its IP to the limit imposed by the quality standard (8 h). The following rank, in terms of effectiveness, was obtained: PY > propyl gallate (PG) > butylated hydroxytoluene (BHT) > tert-butyl hydroquinone (TBHQ). In agreement, the stabilization factors (F), considering the use of 204 ppm of antioxidant, were: 5.84 for PY, 4.06 for PG, 1.85 for BHT and 0.85 for TBHQ

Simple, sensitive and quantitative bioluminescence assay for determination of malaria pre-patent period

© 2014 Zuzarte-Luis et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stateBackground: The first phase of malaria infection occurs in the liver and is clinically silent. Inside hepatocytes each Plasmodium sporozoite replicate into thousands of erythrocyte-infectious merozoites that when released into the blood stream result in clinical symptoms of the disease. The time between sporozoite inoculation and the appearance of parasites in the blood is defined as the pre-patent period, which is classically analysed by time-consuming and labor-intensive techniques, such as microscopy and PCR. Methods: Luciferase-expressing Plasmodium berghei parasites were used to measure pre-patent period of malaria infection in rodents using a bioluminescence assay that requires only one microliter of blood collected from the tail-vein. The accuracy and sensitivity of this new method was compared with conventional microscopy and PCR based techniques, and its capacity to measure the impact of anti-malarial interventions against the liver evaluated. Results: The described method is very sensitive allowing the detection of parasites during the first cycles of blood stage replication. It accurately translates differences in liver load due to inoculation of different sporozoite doses as well as a result of treatment with different primaquine regimens. Conclusions: A novel, simple, fast, and sensitive method to measure pre-patent period of malaria infection in rodents is described here. The sensitivity and accuracy of this new method is comparable to standard PCR and microscopy-based techniques, respectively.This work was supported by Fundação para a Ciência e Tecnologia (FCT, Portugal) grants PTDC/SAU-MIC/113697/2009 (VZL) and EXCL/IMI-MIC/0056/2012 (MMM).info:eu-repo/semantics/publishedVersio

Caracterização do património geomorfológico do Parque Natural do Douro Internacional (NE de Portugal) com vista à sua valorização

O Parque Natural do Douro Internacional (PNDI) é uma área protegida pertencente à Rede Nacional de Áreas Protegidas, sob a alçada do Instituto da Conservação da Natureza e da Biodiversidade. O Parque localiza-se no nordeste transmontano, numa área de 851 km2, que acompanha longitudinalmente os rios Douro e Águeda, através de um troço fronteiriço e ao longo de 130 km. Os vales do tipo canhão fluvial com as sua vertentes abruptas, as arribas, destacam-se entre outras geoformas no PNDI. O presente trabalho visa caracterizar e quanti!car a relevância do Património Geomorfológico, inserido no riquíssimo Património Geológico existente na área, bem como a apresentação de propostas de valorização. Foi feita a caracterização dos geomorfossítios inventariados no âmbito dum projecto anterior, tendo-se concluído que os aspectos de maior importância da paisagem do PNDI são o Planalto Mirandês, os relevos residuais, as geoformas graníticas e os vales profundos do rio Douro e afluentes. De seguida, procedeu-se à quantificação da relevância, utilizando uma adaptação dos métodos propostos por Cendrero (2000) e Brilha (2005) para o Património Geológico, obtendo-se uma seriação dos geomorfossítios quanti!cados, o que permite concluir quais os locais com maior potencial para valorização e divulgação. Para a valorização destes geomorfossítios propõem-se várias estratégias como a implementação de painéis interpretativos temáticos, inseridos num percurso rodoviário com o tema “Rota das Arribas”, passando pelos miradouros mais emblemáticos dos rios Douro e Águeda. O Património Geomorfológico do PNDI é um dos ex-libris do Parque, pelo que deverá ser valorizado, constituindo uma importante valência para o impulso do geoturismo na região.The International Douro Natural Park (IDNP) is a protected area that belongs to the Protected Areas National Network, managed by the Nature and Biodiversity Conservation Institute. It is located in northeastern Portugal, with an area of 851 km2. The Park follows the Douro and Águeda rivers, through the border with Spain, along 130 km. The fluvial canyons and cliffs associated with these rivers are important landscape elements in the IDNP. The present work intends to characterize and quantify the relevance of Geomorphological Heritage, inserted in the rich Geological Heritage of this area, as also to present valorization strategies. A characterization of potential geomorphosites identified in a previous project was developed, which highlights the most important elements of the IDNP landscape, namely the Miranda Plain, residual reliefs, granitic landforms and deep valleys of the Douro and the Águeda rivers. A quantitative assessment was also applied, based on a modified version of the models proposed by Cendrero (2000) and Brilha (2005) for the Geological Heritage. A final ranking of the geomorphosites was proposed which establishes the valuable sites that must be included in conservation strategies or selected for geotourism and educational programs. Several strategies were proposed to value these geomorphosites, such as thematic interpretative panels and a car route, the “Arribas Route”, joining the most important viewpoints of the Douro and the Águeda rivers. The Geomorphological Heritage of the IDNP is an ex-libris of this Natural Park. It must be recognized, valued and considered as a major contribution to the geotourism in the region

IMRT Beam Angle Optimization Using Non-descent Pattern Search Methods

https://thekeep.eiu.edu/commencement_spring2015/1304/thumbnail.jp

Recent progress on gellan gum hydrogels provided by functionalization strategies

Gellan gum, a microbial exopolysaccharide fermentation product of Pseudomonas elodea, is a natural biomaterial that has shown promise for tissue engineering and regenerative medicine applications. Although this exopolysaccharide possesses many advantages, such interesting physicochemical properties and non-cytotoxicity, the mechanical properties and processability of gellan gum are not totally satisfactory in different tissue engineering contexts, i.e. gellan gum hydrogels are mechanically weak and the high gelling temperature is also unfavourable. An additional critical limitation is the lack of specific attachment sites for anchorage-dependent cells. However, the multiple hydroxyl groups and the free carboxyl per repeating unit of gellan gum can be used for chemical modification and functionalization in order to optimize its physicochemical and biological properties. A number of physical modification approaches have also been employed. This review outlines the recent progresses for gellan gum hydrogels and derivatives, and identifies the new challenges in tissue engineering, provided by blending and/or chemical modifications.Portuguese Foundation for Science and Technology (FCT) through the project EPIDisc (UTAP-EXPL/BBBECT/0050/2014), funded in the Framework of the ‘‘International Collaboratory for Emerging Technologies, CoLab’’, UT Austin Portugal Program.FCT for the fellowship grant SFRH/BPD/100590/2014FCT program (IF/00423/2012

Exploring the Impact of a Gamified Exercise Platform to Support Healthy Ageing:Home-Based Study with Older Adults

Active ageing is an increasingly important concept within society due to the ageing of the world population and search for enhanced quality of life. Technological resources such as serious games can be used as a means to promote healthier lifestyle and ageing, particularly in older adults. This study intended to explore the effects of using a digital approach composed of serious games to support physical and cognitive exercise at home, to support healthy ageing. Eleven older adults voluntarily participated in an eight-day home-based study. The aim of the study was to explore the feasibility of the digital approach in autonomous sessions at home, by measuring satisfaction and motivation, and assessing the impact of different gamification strategies. The results showed that participants exercised autonomously on average on 5.5 out of the 8 days. Each session had an average duration of 35 minutes. Moreover, participants reported an average satisfaction of 80.0% throughout the sessions. Yet, the findings indicate that system usability should still be improved. Participants provided suggestions towards an easier user experience, pointing for example to the importance of personalized exercise plans. The findings suggest that gamification strategies focused on multi-joint and dynamic exercises were preferred over single limb and more monotonous exercises. The current study highlights the potential of home-based digital solutions to support healthy ageing in older adults and provide suggestions for future endeavors in this area.</p

Saccharomyces cerevisiae as a host for chondroitin production

Chondroitin is a glycosaminoglycan that has gained widespread use in nutraceuticals and pharmaceuticals, mainly for treating osteoarthritis. Traditionally, it has been extracted from animal cartilage but recently, biotechnological processes have emerged as a commercial alternative to avoid the risk of viral or prion contamination and offer a vegan-friendly source. Typically, these methods involve producing the chondroitin backbone using pathogenic bacteria and then modifying it enzymatically through the action of sulfotransferases. Despite the challenges of expressing active sulfotransferases in bacteria, the use of eukaryotic microorganisms is still limited to a few works using Pichia pastoris. To create a safer and efficient biotechnological platform, we constructed a biosynthetic pathway for chondroitin production in S. cerevisiae as a proof-of-concept. Up to 125 mg/L and 200 mg/L of intracellular and extracellular chondroitin were produced, respectively. Furthermore, as genome-scale models are valuable tools for identifying novel targets for metabolic engineering, a stoichiometric model of chondroitin-producing S. cerevisiae was developed and used in optimization algorithms. Our research yielded several novel targets, such as uridine diphosphate (UDP)-Nacetylglucosamine pyrophosphorylase (QRI1), glucosamine-6-phosphate acetyltransferase (GNA1), or N-acetylglucosamine-phosphate mutase (PCM1) overexpression, that might enhance chondroitin production and guide future experimental research to develop more efficient host organisms for the biotechnological production process.This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UIDB/04469/2020 unit with DOI 10.54499/UIDB/04469/2020. The authors acknowledge FCT for funding MRC doctoral grant SFRH/BD/132998/2017 and further extension COVID/BD/152454/2022.info:eu-repo/semantics/publishedVersio

Valorization of seaweed carbohydrates: autohydrolysis as a selective and sustainable pretreatment

Seaweeds are promising feedstocks; nevertheless, the lack of systematic approaches to recover different high-value fractions in a clean and sustainable mode hampers their exploitation. Due to this necessity, an innovative environmentally friendly strategy was proposed in this article for the development of a sugar platform from Gelidium sesquipedale: for the first time, autohydrolysis followed by enzymatic saccharification (with cellulolytic and agarolytic cocktails) was applied to agarophyte seaweeds. The wide range of severities (between 2.47 and 4.94) studied in this work proved that the autohydrolysis-based process can be tuned to selectively extract different target carbohydrate fractions. Gelling agents (reaching 30 g/100 g DW) can be obtained by the application of low severity treatments, fermentable sugars or oligosaccharides with the nutraceutical potential (reaching 14 g/100 g DW) are produced when severity is increased, and at the highest severity, platform chemicals (reaching 4 g/100 g DW) are the final product. The reduction of processing times compared to traditional extraction methodologies and the elimination of chemicals used in dilute acid treatments make this strategy a clean and sustainable alternative for the valorization of both glucan and galactan fractions of G. sesquipedale.This work was supported by the Portuguese Foundation forScience and Technology (FCT), under the scope of thestrategic funding of UID/BIO/04469/2020 unit and under thescope of the project “AlgaePlas-Biorefinery of macroalgae forvalorization of the carbohydrate fraction to sustainablebioplastics,”PTDC/BII-BIO/29242/2017.info:eu-repo/semantics/publishedVersio

Advances on the development of novel heterogeneous catalysts for transesterification of triglycerides in biodiesel

This paper describes experimental work done towards the search for more profitable and sustainable alternatives regarding biodiesel production, using heterogeneous catalysts instead of the conventional homogenous alkaline catalysts, such as NaOH, KOH or sodium methoxide, for the methanolysis reaction. This experimental work is a first stage on the development and optimization of new solid catalysts, able to produce biodiesel from vegetable oils. The heterogeneous catalytic process has many differences from the currently used in industry homogeneous process. The main advantage is that, it requires lower investment costs, since no need for separation steps of methanol/catalyst, biodiesel/catalyst and glycerine/catalyst. This work resulted in the selection of CaO and CaO modified with Li catalysts, which showed very good catalytic performances with high activity and stability. In fact FAME yields higher than 92% were observed in two consecutive reaction batches without expensive intermediate reactivation procedures. Therefore, those catalysts appear to be suitable for biodiesel production