Computational Fluid Dynamics is a quite well established tool for carrying out realistic simulations of process apparatuses. However, as a difference from single phase systems, for multiphase systems ...the development of CFD models is still in progress. Among the two-phase systems, gas–liquid systems are characterised by an additional complexity level, related to the fact that bubble sizes are not known in advance, being rather the result of formation and breakage-coalescence dynamics and therefore of complex phenomena related to flow dynamics and interfacial effects. In the present work, Euler–Euler Reynolds-averaged flow simulations of an air-lift reactor are reported. All bubbles are assumed to share the same size, and a simplified approach is adopted for modelling inter-phase momentum exchange, that involves bubble terminal velocity as the sole parameter needed. Good agreement between simulation results and literature experimental data is found for all the gas flow rates simulated. This result implies that, despite the many simplifications that have to be adopted in order to make them viable, fully predictive CFD simulations of gas–liquid systems can give rise to reasonably accurate predictions of reactor fluid dynamics.
R5; AIM: To investigate the relationship between ferritin and steatosis in patients with chronically abnormal liver function tests (LFTs) and high ferritin level. METHODS: One hundred and twenty-four ...consecutive patients with hyperferritinemia (male > 300 ng/mL, female > 200 ng/mL) were evaluated; clinical, biochemical and serological data, iron status parameters, HFE gene mutations and homeostasis model assessment score were obtained. Steatosis was graded by ultrasound as absent or present. Histology was available in 53 patients only. RESULTS: Mean level of ferritin was 881 ± 77 ng/mL in men and 549 ± 82 ng/mL in women. The diagnosis was chronic hepatitis C in 53 (42.7%), non-alcoholic fatty liver disease/non-alcoholic steatohepatitis in 57 (45.9%), and cryptogenic liver damage in 14 (11.3%). None was diagnosed as hereditary hemochromatosis (HH). Hepatic siderosis on liver biopsy was present in 17 of 54 (32%) patients; grade 1 in eight and grade 2 in nine. Overall, 92 patients (74.2%) had steatosis. By logistic regression, ferritin and g-glutamyltransferase were independent predictors of steatosis. Ferritin levels were significantly related to low platelet count, steatosis and hepatitis C virus infection. CONCLUSION: In a non-obese cohort of non-alcoholic patients with chronically abnormal LFTs without HH, high serum ferritin level is a risk factor for steatosis.
Astrobiology, a new exciting interdisciplinary research field, seeks to unravel the origin and evolution of life wherever it might exist in the Universe. The current view of the origin of life on ...Earth is that it is strongly connected to the origin and evolution of our planet and, indeed, of the Universe as a whole. We are fortunate to be living in an era where centuries of speculation about the two ancient and fundamental problems: the origin of life and its prevalence in the Universe are being replaced by experimental science. The subject of Astrobiology can be approached from many different perspectives. This book is focused on abiogenic organic matter from the viewpoint of astronomy and planetary science and considers its potential relevance to the origins of life on Earth and elsewhere. Guided by the review papers in this book, the concluding chapter aims to identify key questions to motivate future research and stimulate astrobiological applications of current and future research facilities and space missions. Today's rich array of new spacecraft, telescopes and dedicated scientists promises a steady flow of discoveries and insights that will ultimately lead us to the answers we seek.
Iron overload disease: recent findings Licata, Anna; Brucato, Virna; Di Marco, Vito ...
Annali italiani di medicina interna,
2004 Jul-Sep, Letnik:
19, Številka:
3
Journal Article
Iron overload diseases are due to a progressive increase in total body iron stores that leads to deposition of iron in parenchymal organs and to subsequent damage to these organs. The commonest ...inherited form of iron overload is hereditary hemochromatosis (HH), an autosomal recessive disorder affecting the white population. Although in the western world and in northern Europe the majority of cases of HH are associated with an HFE gene mutation (C282Y and H63D), there are families with a familial iron overload disorder in whom neither the C282Y nor the H63D mutations were found. Recently, other forms of HH that are not related to HFE, but are due to mutations in genes coding iron transport proteins (ferroportin-1, TfR2, hepcidin) have been described. The clinical presentation of the disorder is highly variable, depending on the severity of iron overload. In fact, the inappropriate absorption and deposition of dietary iron may result in the development of hepatic and non-hepatic end-organ injury, leading to liver cirrhosis, hepatocellular carcinoma, diabetes, arthritis, skin pigmentation and cardiac diseases. HH and its sequelae are preventable with an early diagnosis and treatment. Patients with evidence of iron overload, a family history of HH or other risk factors should be screened by genotype testing for the HFE mutation. Nowadays, HH is recognized as being a complex genetic disease with probable significant environmental and genetic modifying factors, such as hepatitis C virus infection and alcohol abuse, and it has been shown that HFE mutations represent an independent risk factor for fibrosis and cirrhosis in chronic hepatitis C.
Magnesium plays a key role in regulating insulin action, insulin-mediated glucose uptake, and vascular tone. Intracellular magnesium depletion may result in a defective tyrosine—kinase activity at ...the insulin receptor level, in a postreceptorial impairment in insulin action, and clinically in a worsening of insulin resistance. Intra- and extracellular alterations of magnesium metabolism have been identified in clinical states characterized by insulin resistance, such as metabolic syndrome, hypertension, altered glucose tolerance, type 2 diabetes, and aging. Several studies, from our and other’s groups, have confi rmed the clinical relevance of alterations of magnesium homeostasis in these conditions and have highlighted the importance of an accurate definition of the magnesium status. While measurements of total serum magnesium levels have been proven inadequate for this purpose because important magnesium depletions are required before total serum level decreases, two technologies, 31P nuclear magnetic resonance (31P-NMR) spectroscopy and magnesium-specifi c ion-selective electrodes, that, respectively, measure intracellular and extracellular free levels of magnesium, have a higher sensitivity in detecting magnesium deficits. A number of evidences have confirmed that magnesium supplementation is indicated in conditions associated with magnesium deficit, although well-designed therapeutic trials with oral magnesium supplements to study the beneficial effects in metabolic syndrome and in type 2 diabetes are needed.
The subject of Astrobiology can be approached from many different perspectives, as reflected in numerous textbooks, journals, conference proceedings, web documentation and popular literature. This ...book is focused on abiotic organic matter from the viewpoint of astronomy and planetary science and considers its potential relevance to the origins of life on Earth and elsewhere. Guided by the review papers in this book, this concluding chapter aims to identify key questions to motivate future research and stimulate astrobiological applications of current and future research facilities and space missions.
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