Exercise biomechanics for health: evaluating lifelong activities for well-being

Biomechanics is a multidisciplinary study of the mechanical laws and principles that govern human movement and the functioning of biological systems [1]. In the context of physical activity, exercise and physical fitness, biomechanics plays a crucial role in understanding the most efficient and effective ways to improve health and well-being. In addition, biomechanics aim to improve athletes’ performance as well as the movement efficiency of the whole population, leading to a better quality of life. To that end, concerns about optimal economy of movement, strength, power, stability, postural alignment, range of motion and athletic performance are some of the most important topics to address in the study of exercise biomechanics [2].info:eu-repo/semantics/publishedVersio

Development of foam-free biosurfactant production processes using Bacillus licheniformis

Microbial biosurfactants are considered environmentally friendly alternatives to synthetic surfac-tants in numerous applications. One of the main bottlenecks to their widespread use is the lack of effective processes for their production on an industrial scale. Biosurfactant production using conventional aerated bioreactors results in excessive foaming due to the combination of air injec-tion and their tensioactive properties. A not widely explored approach to overcome this problem is the development of foam-free production processes, which require the identification and charac-terization of appropriate microorganisms. Bacillus licheniformis EL3 was evaluated for biosurfac-tant production under oxygen-limiting conditions in a bioreactor, using a mineral medium con-taining glucose as a carbon source and NaNO3 and NH4Cl as nitrogen sources. After optimizing the operational conditions, glucose concentration, and inoculum strategy, B. licheniformis EL3 produced 75 ± 3 mg biosurfactant/L in 43 h. The purified biosurfactant exhibited exceptional sur-face active properties, with minimum surface tension values (29 mN/m) and a critical micelle concentration (27 mg/L) similar to those achieved with commercial surfactin. Furthermore, bio-surfactant yield per substrate (YP/S = 0.007 g biosurfactant/g glucose) was similar to the figures re-ported for Bacillus subtilis strains grown in similar conditions, whereas biosurfactant yield per bi-omass (YP/X = 0.755 g biosurfactant/g biomass) and specific biosurfactant productivity (qBS = 0.018 g biosurfactant/(g biomass × h)) were almost three times higher when compared to previous reports. The results obtained indicate that B. licheniformis EL3 is a promising candidate for the develop-ment of foam-free biosurfactant production processes at an industrial scale.The authors acknowledge the Portuguese Foundation for Science and Technology (FCT) for financial support under the scope of the strategic funding of the UIDB/04469/2020 unit, with DOI 10.54499/UIDB/04469/2020, and LABBELS—Associate Laboratory in Biotechnology, Bioengineering and Microelectromechanical Systems, LA/P/0029/2020. Eduardo J. Gudiña thanks FCT for the research contract DL 57/2016/CP1377/CT0039 (DOI 10.54499/DL57/2016/CP1377/CT0039).info:eu-repo/semantics/publishedVersio

Improved rhamnolipid biosurfactant production by Burkholderia thailandensis E264 using agro-industrial waste

Biosurfactants are amphiphilic surface-active compounds, produced by various microorganisms, that reduce surface and interfacial tension. These compounds are attracting increasing interest over their chemical counterparts due to their advantages, such as biodegradability, high stability in extreme environments, low toxicity, low critical micelle concentrations (CMC) and the fact that they can be effectively produced from agro-industrial wastes and renewable resources. Furthermore, their diversity allows for a significant number of uses, including microbial enhanced oil recovery (MEOR), bioremediation and biomedical applications. However, the high operational costs, mainly regarding the use of expensive raw materials in the fermentation and the complex downstream processing, to yield low amounts of product restricts their industrial-scale applications. Several attempts to solve these limitations by reducing the production costs have been conducted and include the use of low-cost agro-industrial wastes and by-products as substrates. One of these low-cost substrates, that has been successfully used to produce biosurfactants by Bacillus subtilis and Pseudomonas aeruginosa strains, is Corn Steep Liquor (CSL). In this research, rhamnolipid biosurfactant production by Burkholderia thailandensis E264 was optimized using this agro-industrial waste as sole substrate. When grown in a culture medium containing CSL (7.5% v/v), this strain produced 1.77 g biosurfactant/L, which is about 2.6 times the amount of biosurfactant produced in the standard synthetic medium. The purified biosurfactant produced in the low-cost medium exhibited similar surface-active properties when compared with that produced in the synthetic medium, reducing the surface tension of water to 29.7 mN/m, with a CMC of 385 mg/L. HPLC analysis showed that the culture medium used contains about 2.6 g/L of fructose and 2.5 g/L of glucose, that are fully consumed within the first 48 h of fermentation. Since the synthetic medium contains 40 g/L of glycerol, results suggest that biosurfactant production is more efficient in the low-cost medium. Furthermore, to the best of the authors knowledge, this is the first experimental research that combines the utilization of B. thailandensis with CSL to produce biosurfactants with very optimistic results in terms of cost and production levels. The rhamnolipid-containing cell-free supernatant could be used directly in bioremediation or MEOR processes.This study was supported by PARTEX Oil and Gas, and the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UIDB/04469/2020 unit and BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund (ERDF) under the scope of Norte 2020 - Programa Operacional Regional do Norte. The authors also acknowledge to the Biomass and Bioenergy Research Infrastructure (BBRI)- LISBOA-01-0145-FEDER-022059, supported by Operational Program for Competitiveness and Internationalization (PORTUGAL2020), by Lisbon Portugal Regional Operational Program (Lisboa 2020) and by North Portugal Regional Operational Program (Norte 2020) under the Portugal 2020 Partnership Agreement, through the ERDF.info:eu-repo/semantics/publishedVersio

Hidrogeologia

Versão revista e actualizada do capítulo "Hidrogeologia" da Notícia Explicativa da Folha 6-D, Vila Pouca de Aguiar, da Carta Geológica de Portugal, escala 1:50.00

A contribuição de Donald C. Hambrick para a teoria do alto escalão – um estudo bibliométrico

Objective: Our objective was to investigate the impact of Donald C. Hambrick’s contributions to the Upper Echelon Theory (UET).Approach: A bibliometric study of citations and co-citations in articles which refer to research published by the author on UET.Results: In this study, we confirmed the relevance of articles published by Hambrick on the UET over time, revealed the association of the UET with different theoretical currents in Management and identified current research fronts on the subject.Limitations: The search for citations to Hambrick’s work on UET was limited to articles published in peer-reviewed academic journals, which eliminated part of the author’s research on the subject. We obtained the citations to Hambrick’s articles on UET exclusively from the ISI Web of Knowledge database, which uses highly selective criteria for choosing indexed publications indexed.Practical implications: Based on the results, we point out opportunities for further investigation into topics regarding Upper Echelons Theory, application and analysis in new contexts.Originality / Relevance: This is the first known bibliometric study to analyze all Hambrick’s articles on the UET.Objetivo: Investigar el impacto de las contribuciones de Donald. C. Hambrick para la teoría de los escalafones superiores - UET.Enfoque: Estudio bibliométrico de citas y co-citas de artículos que hacen referencia a investigaciones publicadas por Donald C. Hambrick sobre el tema de la UET.Resultados: Con este estudio, se confirmó la relevancia de los artículos publicados por Hambrick sobre UET a lo largo del tiempo, la asociación de UET con diferentes corrientes teóricas en el campo de la Administración, y se identificaron los frentes de investigación actuales sobre el tema.Limitaciones de la investigación: La búsqueda de citas del trabajo de Hambrick en UET se limitó a los artículos que publicó en revistas académicas revisadas por pares, lo que eliminó parte de su investigación sobre el tema de la búsqueda. Las citas de los artículos de Hambrick sobre UET se obtuvieron exclusivamente de la base de datos de ISI Web of Knowledge, que utiliza criterios declaradamente selectivos para la elección de publicaciones indexadas en ella.Implicaciones prácticas: La investigación identifica oportunidades para futuras investigaciones sobre temas asociados con la teoría de los escalafones superiores y para su aplicación y análisis en nuevos contextos.Originalidad / Valor: Este es el primer estudio bibliométrico conocido que incluye el análisis de todos los artículos de Hambrick sobre la UET.Objetivo: Investigar o impacto das contribuições de Donald. C. Hambrick para a Teoria do Alto Escalão (Upper Echelon Theory - UET).Abordagem: Estudo bibliométrico de citações e cocitações dos artigos que referenciam pesquisas publicadas por Donald C. Hambrick sobre o tema UET.Resultados: Com este estudo, confirmou-se a relevância dos artigos publicados por Hambrick sobre a UET ao longo do tempo, a associação da UET a diferentes correntes teóricas no campo da Administração e identificaram-se frentes de pesquisa atuais sobre o tema.Limitações da pesquisa: A pesquisa de citações da obra de Hambrick sobre UET foi limitada aos artigos por ele publicados em revistas acadêmicas revisadas por pares, o que eliminou da busca parte de sua produção sobre o tema. As citações aos artigos de Hambrick sobre UET foram obtidas, exclusivamente, na base ISI Web of Knowledge, que utiliza critérios declaradamente seletivos para a escolha de publicações nela indexadas.Implicações práticas: A pesquisa identifica oportunidades de investigação adicional em temas associados à Teoria do Alto Escalão e para sua aplicação e análise em novos contextos.Originalidade/Valor: Este é o primeiro estudo bibliométrico conhecido que compreende a análise de todos os artigos de Hambrick sobre a UET

Estudo experimental de escoamentos em regime uniforme e não uniforme em canais de secção composta

Dissertação apresentada para obtenção do grau de Mestre em Engenharia CivilApesar de os escoamentos dos rios se realizarem usualmente no leito principal, em situações de cheia a capacidade de vazão deste é excedida e o escoamento faz-se também nos campos adjacentes, denominados por leitos de cheia, obtendo uma configuração de secção composta. Como na zona do leito principal a profundidade é maior do que a do leito de cheia, existe uma diferença de velocidades entre eles que dá origem a interacções e a transferências de massa e de quantidade de movimento. Nestas condições as características do escoamento não se encontram bem definidas devido ao grande número de variáveis. Esta dissertação pretende, através de caracterização experimental, estudar os mecanismos envolvidos no escoamento neste tipo de canais bem como na interacção entre o leito principal e o leito de cheias. A componente experimental incluiu a recolha e tratamento de dados relativos à estrutura turbulenta do escoamento e suas alterações para as situações de regime uniforme e várias destabilizações em regime não uniforme. Verificou-se que as condições de regime não uniforme podem afectar a camada de mistura que se desenvolve na interface entre o leito principal e cada leito de cheia. Esses efeitos podem ser observados nas tensões turbulentas e na tensão aparente, e devem-se à transferência de massa entre os leitos e a alteração do gradiente lateral da velocidade longitudinal