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A nonlinear dynamic model for natural circulation drum-boilers is presented. The model describes the complicated dynamics of the drum, downcomer, and riser components. It is derived from first principles, and is characterized by a few physical parameters. A strong effort has been made to strike a balance between fidelity and simplicity. Results from validation of the model against unique plant dat
Endovascular treatment of aneurysmal disease of descending thoracic aorta and infra-renal abdominal aorta, has become an accepted technique, in selected cases due to the reduction of neurological morbidity, paraparesis or paraplegic and renal ischemia, associated with conventional surgery. The authors describe the first case performed in Portugal of a 75-year-old female with an expanding thoracic
X-rays from a laser-produced plasma were analysed using single-photon counting germanium detectors. Special attention was given to the extremely high photon flux, requiring either a long source-detector distance and narrow collimated measurement geometry in order to avoid severe pile-up of pulses in the spectrometer, or the use of a Compton scattering geometry. With the use of these techniques, in
Fractionation of 3T3-L1 adipocyte membranes revealed that PDE3B (phosphodiesterase 3B) was associated with PM (plasma membrane) and ER (endoplasmic reticulum)/Golgi fractions, that insulin-induced phosphorylation/activation of PDE3B was greater in internal membranes than PM fractions, and that there was no significant translocation of PDE3B between membrane fractions. Insulin also induced formatio
Popular Abstract in Swedish Efter den senaste istiden har klimatet varit dynamiskt med både stora och snabba klimatförändringar, om än inte av samma storlek som under istiden. Hur utbredda och vilka effekter dessa klimatförändringar har haft är dock inte helt kartlagt. Målet med denna avhandling är att i detalj rekonstruera de klimat- och miljöförändringar som har påverkat ögruppen Tristan da CunhIt has been shown that the present interglacial has been climatically dynamic with both rapid and severe climatic fluctuations. The spatial and temporal differences of these changes are however not fully resolved. The aim of this thesis is to present a detail high resolution record of past climate changes from the central South Atlantic. Peat and lacustrine sediment sequences were retrieved from
The generation of mice lacking specific components of the transforming growth factor-beta (TGF-beta) signal tranduction pathway shows that TGF-beta is a key player in the development and physiology of the cardiovascular system. Both pro- and anti-angiogenic properties have been ascribed to TGF-beta, for which the molecular mechanisms are unclear. Here we report that TGF-beta can activate two disti
The aim of the present study was to analyse quantitatively, on a cat gastrocnemius muscle preparation in vivo, the effects of local angiotensin-converting enzyme (ACE) inhibition by enalaprilat on total regional vascular resistance (tone) and its distribution to the large-bore arterial resistance vessels (> 25 microns), the small arterioles (< 25 microns) and the veins. Associated effects on capil
From cultures of Mycogone cervina, a mycophilic fungus growing on the fruit bodies of ascomycete Paxina acetabulum, two new peptaibols (cervinin, N-Ac-Leu-Aib-Pro-Aib-Leu-Aib-Pro-Ala-Aib-Pro-Val-red-Leu (1) and the red-Leu O-acetylated derivative 2) were isolated. The structures of 1 and 2 were elucidated by spectroscopic techniques. They exhibited weak antibacterial as well as cytotoxic activitie
Samples from patients with Clostridium difficile-associated diarrhea (CDAD) that were randomized to fusidic acid (n = 59) or metronidazole (n = 55) therapy for 7 days were cultured for Clostridium difficile in feces on days 1, 8 to 13, and 35 to 40. Of the patients who were culture positive only before treatment, 77% (36/47) were permanently cured (no treatment failure and no clinical recurrence),
The dissociation of DNA-cationic surfactant complexes with the addition of a negative amphiphile was studied by fluorescence microscopy (FM). The unfolding of DNA molecules previously compacted with cationic surfactant was shown to be dependent on the anionic surfactant chain length; lower amounts of a longer-chain surfactant were needed to release DNA into solution. However, we observed no depend
Comprehensive palliative care programs are often implemented on a community level, and to evaluate such interventions, randomization by cluster (community) may be the only feasible method. In trials randomizing individual subjects, the importance of proper concealment has been stressed, In cluster randomized trials, however, concealment of individual patient allocation is often impossible. The fol
Incubation of rat adipocytes with wortmannin, a potent and selective phosphatidylinositol 3-kinase (PI 3-kinase) inhibitor, completely blocked the antilipolytic action of insulin (IC50 = 100 nM), the insulin-induced activation and phosphorylation of cGMP-inhibited cAMP phosphodiesterase (cGI-PDE) as well as the activation of the insulin-stimulated cGI-PDE kinase (IC50 = 10-30 nM). No direct effect
The interference between extrinsic and intrinsic losses in x-ray absorption fine structure (XAFS) is treated within a Green's-function formalism, without explicit reference to final states. The approach makes use of a quasiboson representation of excitations and perturbation theory in the interaction potential between electrons and quasibosons. These losses lead to an asymmetric broadening of the
