Search results for " circulation"
showing 10 items of 758 documents
A novel oxovanadate structural type – Synthesis, single crystal structure and magnetic properties of a mixed-valence polyoxovanadate formed by {V17O4…
2007
Abstract A novel polyoxovanadate structural type, with an average nuclearity of V16, formed by a mixture of two different polyoxovananadates: {V15O36(Cl)} and{V17O40(Cl)} has been synthesized and characterized. The title compound, formulated as [Ni(phen)3]2{[V15O36(Cl)]0.5[V17O40(Cl)]0.5} · H2O (1) (phen = 1,10′-phenanthroline), presents two different polyoxovanadate architectures: {V15O36(Cl)} and {V17O40(Cl)}, with the last one representing a new framework type in polyoxovanadate chemistry. Here, we present the synthesis of this novel polyoxovanadate under hydrothermal conditions and its characterization by IR and XPS spectroscopies, elemental and thermogravimetric analysis, redox titrati…
Snapshots of the Formation of NaTi3O6(OH)·2H2O Nanowires: A Time-Resolved XRD/HRTEM Study
2013
Layered titanates are important intermediates during the formation of TiO2-related nanostructures in hot concentrated base solution. Microwave-assisted hydrothermal techniques allow a time-resolved ex-situ analysis of the reaction in one-minute intervals by rapid heating and quenching followed by separation and structure analysis of the intermediates. By a combination of powder X-ray diffraction, high resolution electron microscopy (HRTEM), and selected area electron diffraction (SAED) the individual stages of the reaction could be identified. Sodium titanate nanosheets are formed within several minutes by digesting the crystalline TiO2-P25 precursor in NaOH. These nanosheets with a low sod…
Dissociation of theophylline uptake and inotropic effect in myocardial tissue: influence of temperature, pH and calcium.
1975
1. The myocardial uptake and the positive inotropic effect of theophylline (100 mug/ml; 0.56 mM) were studied in isolated electrically driven guinea-pig hearts perfused by the Langendorff technique under various extracellular conditions. [3H]-theophylline was used. 2. Variations in temperature, hydrogen ion and calcium ion concentrations of the perfusion media changed the time course and magnitude of the effect of theophylline on myocardial twitch tension but did not affect the time course and amount of theophylline uptake. 3. Under all conditions, the build-up of the positive inotropic effect of theophylline was about three times faster than the uptake of the drug into the heart. 4. Since …
Transcranial Doppler and Cortical Microcirculation at Increased Intracranial Pressure and during the Cushing Response
1995
The effect of increased intracranial pressure on the flow velocity of the basilar artery was measured with transcranial ultrasonic Doppler in New Zealand White rabbits under alpha-chloralose anesthesia and artificial respiration. Laser Doppler flowmetry served to study changes of the cortical microcirculation. The results confirm a high inverse correlation of the diastolic flow velocity, the pulsatility index, and the resistance index with the cerebral perfusion pressure (CPP). During acute intracranial hypertension, however, these parameters do not show a good correlation with the local cortical blood flow. The absence of a correlation was evident over a wide CPP range down to values of 35…
Zur Wirkung von Muskelrelaxantien auf den intraokularen Druck
1988
Since general anesthesia is being used increasingly in ophthalmic surgery, the effects of anesthetic drugs on intraocular pressure (IOP) have to be considered. Competitive neuromuscular blocking drugs either do not affect IOP or produce a slight decrease. Depolarizing muscle relaxants increase IOP. This effect, which is pronounced with succinylcholine, cannot be reliably prevented by any concomitant medication. The new competitive relaxants atracurium and vecuronium provide stable conditions with respect to IOP and systemic circulation, combined with fast onset and intermediate duration of action.
Seasonal changes in glacial polynya activity inferred from Weddell Sea varves
2013
Abstract. The Weddell Sea and the associated Filchner–Rønne Ice Shelf constitute key regions for global bottom-water production today. However, little is known about bottom-water production under different climate and ice-sheet conditions. Therefore, we studied core PS1795, which consists primarily of fine-grained siliciclastic varves that were deposited on contourite ridges in the southeastern Weddell Sea during the Last Glacial Maximum (LGM). We conducted high-resolution X-ray fluorescence (XRF) analysis and grain-size measurements with the RADIUS tool (Seelos and Sirocko, 2005) using thin sections to characterize the two seasonal components of the varves at sub-mm resolution to distingui…
High-skilled migration and the knowledge society. Theories, processes, perspectives
2018
The recent economic crisis has led to an upswing in migration from the Mediterranean countries of Europe towards its central and northern development hubs. This overall increase in migration also includes high numbers of the so-called skilled migrants, consisting mainly, though not exclusively, of young people moving within Europe for study or specialisation, or seeking employment that matches their skills profile. It is no coincidence then that this new trend for skilled migration within Europe forms the main thrust of the cognitive and research interests of sociologists, economists and migration geographers. The aim of this paper is to reconstruct the theoretical debate on skilled migrati…
A Tropical Archipelago
2017
The tropical maritime climate of the Philippines is marked by high temperature and abundant rainfall. The chapter first examines the major characteristics of the climate, dominated by the seasonal alternation of the Amihan and Habagat monsoons, leading to sharp differences between regions for their patterns of rainy seasons. Typhoons from the western Pacific hit the islands with brutal force, even if some years are more prone than others to the onslaught of tropical storms, depending on the general atmospheric circulation and the strength—or absence—of El Nino or La Nina. Typhoons not directly hitting the Philippines can still generate high levels of rainfall and enhance flooding, due to th…
CAN RETURN MIGRATION REVITALISE LATVIA’S REGIONS? FACILITATORS AND BARRIERS TO HUMAN CAPITAL GAINS
2021
Migration researchers from East-Central Europe most often focus on the impact of ‘brain drain’ which is characterised by the loss of human capital from emigration. In this paper focus is placed on the assumption that migrants living abroad gain valuable experiences and education opportunities, that lead to personal growth, facilitate entrepreneurship and psychological resilience, amongst other important skills. This experience may be used for the revitalisation of the less-developed regions the migrants return to. To explore what facilitates or inhibits the fulfil potential of ‘brain circulation’ or gain, we use data from two large-scale surveys of return migrants in Latvia, in-depth interv…
High-intensity transient signals during laparoscopic surgery in children.
2009
Background Laparoscopic interventions in children gain increasing popularity. Pneumoperitoneum as applied during laparoscopic surgery can induce gas emboli formation, but it is unclear whether this is associated with cerebral embolic events. To investigate the hypothesis that pneumoperitoneum causes cerebral emboli in children, the number and intensity of high-intensity transient signals (HITS) detected using transcranial Doppler ultrasonography were assessed before and after induction of pneumoperitoneum. Methods Twenty children were monitored during laparoscopic surgery. General anaesthesia was performed using sevoflurane and sufentanil or alfentanil. Pressure-controlled ventilation was a…