48 resultados para secondary metabolism


Relevância:

20.00% 20.00%

Publicador:

Resumo:

The aim of this study was to discover how current chemistry syllabi in the frame curricula for up- per secondary education in three Nordic countries (Finland, Norway, and Sweden) take into account topics related to the nature of chemistry. By qualitative content analysis, the statements related to the nature of chemistry were divided into categories. Conclusions and implications for improving the frame curricula under study were made by comparing results with research into the nature of science. Chemistry syllabi from the Nordic frame curricula analyzed take into account the aims related to the nature of chemistry in a very similar manner. The ideas that should be made more explicit in all of the analyzed curricula are: i) the limits of the chemical models and theories, ii) the relationship between chemistry and other natural sciences, iii) the importance of creativity in chemical research, iv) the concepts of evidence in science texts, v) the social nature of chemical research, and vi) chemistry as a technological practice.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

In this study we investigated the metabolism, i.e. remodeling and translocation, of the aminophospholipids phosphatidylserine (PS) and phosphatidylethanolamine (PE). A new method for introduction of exogenous PS and PE molecular species to cultured cells was developed, and combined with mass spectrometry it enabled more detailed follow-up of the metabolism of single molecular species than previously. We found that I) exogenous PS and PE molecular species can be efficiently introduced to cultured cells without compromising cell integrity, II) PS and PE molecular species are remodeled by several phospholipases displaying selectivity based on phopholipid head group and acyl chain composition, III) PS decarboxylase (PSD) and Kennedy pathways provide a different PE molecular species composition to the cellular PE pool. In addition, PE species produced by these pathways are translocated from the site of synthesis to other cell compartments depending on their acyl chain composition. The data obtained in the present study helps to understand cellular phospholipid metabolism in more depth. The data show that effective labeling of cultured cells by exogenous phospholipids does not compromise cell viability and may be used to disturb cellular phospholipid composition to study lipid homeostasis. Remodeling and translocation of PS and PE molecular species is highly selective. The developed method and mass- spectrometric techniques may be used in future studies to understand disturbances in lipid homeostasis for example in diabetes mellitus, thus opening doors to optional scientific approaches to study mechanisms behind pathologies related to lipid disturbances.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Acute respiratory failure (ARF) is the most common type of organ failure leading to the need for intensive care. It is often secondary to acute lung injury (ALI) and its more severe form, acute respiratory distress syndrome (ARDS). ARF, and especially ALI and ARDS, cause increased morbidity, and mortality rates remain high (up to 40%). These disorders are characterised by inflammatory reaction and tissue damage. In some cases, inflammation continues and leads to an overwhelming repair process with ongoing fibrosis, accompanied by organ dysfunction and eventually a loss of function. Measuring the magnitude of the inflammation, and the repair process, would theoretically offer information concerning outcome. Early identification of patients whose disease process is likely to proceed unfavourably, would help clinicians to optimise their treatment. The aim of this study was to evaluate the epidemiology of ARF, its treatment, and outcome in Finland, with special interest in biomarkers, and their value in the prediction of mortality. Altogether, 958 adult patients treated with ventilatory support were prospectively included in this study during an eight week period in 2007 in 25 intensive care units. Plasma aminoterminal pro-brain natriuretic peptide (NT-pro-BNP) was assessed in 602 patients, and plasma cell-free DNA in 580 patients, to evaluate their prognostic value in ARF. Markers of collagen metabolism were studied in longitudinal serum samples in 68 patients in order to evaluate their evolution in ARF and the association to multiple organ dysfunction (MOD). Ventilatory support was used in 39% of all ICU patients. The estimated incidence of ARF was 149.5/100 000 per year. Median tidal volumes used were higher than recommended. Overall mortality at 90 days was 31%. Plasma NT-pro-BNP and cell-free DNA were highly increased in the majority of patients. Both markers were independent predictors of 90-day mortality, but their discriminative power was at most moderate when used separately. The mortality was highest in those patients, in whom both biomarkers were over their separate cut-off values. Thus, combined use of these biomarkers may increase their clinical value in the mortality prediction. The markers of collagen metabolism changed significantly over time in surviving patients. None of these markers did associate with MOD in these patients.