Modelling lipase-catalysed transesterification of fats containing n-3 fatty acids monitored by their solid fat contentTransesterification of fat blends rich in n-3 polyunsaturated fatty acids (n-3 PUFA), catalysed by a commercial immobilised thermostable lipase from Thermomyces lanuginosa, was carried out batch-wise. Experiments were performed, following central composite rotatable designs (CCRDs) as a function of reaction time, temperature and media formulation. Mixtures of palm stearin, palm kernel oil and a commercial concentrate of triacylglycerols rich in n-3 PUFA ("EPAX 2050TG" in CCRD-1 and "EPAX 4510TG" in CCRD-2) were used. The time-course of transesterification was indirectly followed by the solid fat content (SFC) values of the blend at 10 7C, 20 7C, 30 7C and 35 7C.A decrease in all SFC values of the blends at 10 7C, 20 7C, 30 7C and 357C was observed upon transesterification. The SFC 10 7C and SFC 20 7C of transesterified blends varied between 18 and 48 and SFC 35 7C between 6 and 24. These values fulfil the technological requirements for the production of margarines.Under our conditions, lipid oxidation may be neglected. However, the accumulation up to 8.3% free fatty acids in reaction media is a problem to overcome.The development of response surface models, describing both the final SFC value and the SFC decrease, will allow predicting results for novel proportions of fats and oils and/or a novel combination time-temperature.
ResumoAs células a combustível de óxido sólido (SOFC) são dispositivos capazes de gerar energia elétrica com alta eficiência e baixa emissão de poluentes. As altas temperaturas de operação dessas células (600 a 1000 ºC) são benéficas no sentido de possibilitar a reforma in situ do combustível utilizado, bem como sua aplicação em sistemas de co-geração de energia, aumentando sua eficiência teórica total que pode chegar entre 80 e 85%. Entretanto, essas altas temperaturas, o contato direto entre materiais de constituições químicas diferentes e a utilização de gases redutores e oxidantes, são alguns dos fatores que impõem severas restrições aos materiais usados na preparação de seus principais componentes. O presente artigo tem como objetivo revisar o desenvolvimento do estado da arte, com relação aos materiais de ânodo, cátodo, eletrólito, interconectores e selantes, usados em SOFCs. Os requisitos necessários para o bom funcionamento de cada componente e os materiais que melhor se adequam aos mesmos são descritos. As vantagens e desvantagens dos principais materiais encontrados na literatura são também comentadas e comparadas. Palavras-chave: células a combustível de óxido sólido, ânodo, cátodo, eletrólito.
Abstract
Solid oxide fuel cells (SOFC
Growth hormone is important for the development and function of the immune system, but there is controversy on whether growth hormone deficiency is associated to immune disorders. A model of isolated growth hormone deficiency may clarify if the lack of growth hormone is associated with increased susceptibility to infections, or with an altered responsiveness of the immune system. We have studied the frequency of infectious diseases and the immune function in adults with congenital, untreated isolated growth hormone deficiency. In a cross-sectional study, 35 adults with isolated growth hormone deficiency due to a homozygous mutation in the growth hormone releasing hormone receptor gene and 31 controls were submitted to a clinical questionnaire, physical examination serology for tripanosomiasis, leishmaniasis, HIV, tetanus, hepatitis B and C, and serum total immunoglobulin G, M, E and A measurement. The immune response was evaluated in a subset of these subjects by skin tests and response to vaccination for hepatitis B, tetanus, and bacillus Calmette-Guérin. There was no difference between the groups in history of infectious diseases and baseline serology. Isolated growth hormone deficiency subjects had lower total IgG, but within normal range. There was no difference in the response to any of the vaccinations or in the positivity to protein Purified Derived, streptokinase or candidin. Adult untreated isolated growth hormone deficiency does not cause an increased frequency of infectious diseases, and does not alter serologic tests, but is associated with lower total IgG levels, without detectable clinical impact.
This article reports an effectiveness case study of the individual systemic therapy of a 22‐year‐old Portuguese woman with a diagnosis of paranoid personality disorder, conducted in a university‐based clinic in Lisbon, Portugal. Data were analysed using the hermeneutic single‐case efficacy design, a non‐experimental interpretive approach that aims to determine whether change occurred, whether change was due to therapeutic strategies, and what in therapy caused the change. Results indicate that the treatment was effective and that de‐pathologising Pamina's condition and genogram‐based exploration techniques played a crucial role in her recovery.
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