Search results for "VOLUME"

2016

Background Transcatheter aortic valve implantation (TAVI) has become the treatment of choice in patients with severe aortic valve stenosis who are not eligible for operative replacement and an alternative for those with high surgical risk. Due to high age and smoking history in a high proportion of TAVI patients, suspicious findings are frequently observed in pre-procedural chest computer tomography (CCT).

Clinical Use of Oxygen Stores: Pre-oxygenation and Apneic Oxygenation

1992

During states of respiratory arrest the human oxygen stores may be used therapeutically, regardless of the origin, i.e. either prior to the routinely induced apnea for endotracheal intubation or as an emergency measure in any other case of apnea. The present considerations focus on the clinical use of the oxygen stores available, applying.

Influence of cultivar and concentration of selected phenolic constituents on the in vitro chemiopreventive potential of olive oil extracts.

2011

One of the main olive oil phenolic compounds, hydroxytyrosol (3,4-DHPEA), exerts in vitro chemopreventive activities (antiproliferative and pro-apoptotic) on tumor cells through the accumulation of H2O2 in the culture medium. However, the phenol composition of virgin olive oil is complex, and 3,4-DHPEA is present at low concentrations when compared to other secoiridoids. In this study, the in vitro chemopreventive activities of complex virgin olive oil phenolic extracts (VOO-PE, derived from the four Italian cultivars Nocellara del Belice, Coratina, Ogliarola, and Taggiasca) were compared to each other and related to the amount of the single phenolic constituents. A great chemopreventive po…

TANGENTIAL DEFORMATIONS ON FIBRED POISSON MANIFOLDS

2005

In a recent article, Cattaneo, Felder and Tomassini explained how the notion of formality can be used to construct flat Fedosov connections on formal vector bundles on a Poisson manifold $M$ and thus a star product on $M$ through the original Fedosov method for symplectic manifolds. In this paper, we suppose that $M$ is a fibre bundle manifold equipped with a Poisson tensor tangential to the fibers. We show that in this case the construction of Cattaneo-Felder- Tomassini gives tangential (to the fibers) star products.

Thermodynamic Interaction Parameters for the System Water/NMMO Hydrate

2008

Vapor pressures of water were measured for aqueous solutions of N-methyl-morpholine N-oxide (NMMO) at 80, 90 and 100 degrees C. The Flory-Huggins interaction parameters, chi, calculated from these data as a function of phi, the volume fraction of NMMO, are negative at all concentrations; at low phi, they decrease by more than a factor of 2 as T is raised, whereas they remain almost unchanged as phi approaches unity. Accordingly, the heat of mixing is pronouncedly endothermal at low NMMO concentrations but close to athermal at low water content. The composition dependence of chi can be equally well described by the Redlich-Kister equation and by an approach subdividing the mixing process int…

Volumes, heat capacities and solubilities of amyl compounds in decyltrimethylammonium bromide aqueous solutions

1989

Apparent molar heat capacities and volumes of amylamine (PentNH2) 0.02m, capronitrile (PentCN) 0.02m and nitropentane (PentNO2) 0.009m in decyltrimethylammonium bromide (DeTAB) micellar solutions, in water and in octane were measured at 25°C. By assuming that their concentration approaches the standard infinite dilution state, heat capacities and volumes were rationalized by means of previously reported equations following which the distribution constant between the aqueous and the micellar phase and heat capacity and volume of the additives in both phases are simultaneously derived. The present results are compared to those we have previously obtained for pentanol (PentOH). The thermodynam…

Rheological study and thermodynamic analysis of the binary system (water/ethanol): Influence of concentration

2004

Water is the most widely used solvent in the chemical and pharmaceutical industry, since it is the most physiological and best tolerated excipient. However, in some cases water cannot be used as a solvent because the active substance or solute is insoluble or only slightly soluble in water. For this and other reasons, nonwater solvents may be used possessing the common characteristic of being soluble or mixable in water; as a result, such solvents can be used to prepare binary or tertiary mixtures, etc., with different purposes such as increasing water solubility, or modifying the viscosity or absorption of the dissolved substance, for example. Ethanol, along with other alcohols either alon…

Reactor model for fast reactions in the micro-bubble column and validation

2007

A simple reactor model for predicting conversions in a micro-bubble column is described. It assumes fast reactions so that the gaseous component is readily consumed at the gas-liquid interface. Then, gas-liquid mass transfer becomes determining. As input parameters for the model, the hydrodynamics, specific interfacial area, and mass transport need to be described. Two fast model reactions, the catalytic oxidation of butyraldehyde and the absorption of CO2 in aqueous NaOH, show the applicability of the model but also its limits. The model was used for predicting reaction performance in dependence of operating conditions, in particular to get maximum conversion with the antagonistic paramete…

Partial molar volumes of cobalt(II) chloride in ethanol + water at 298.15 K

1996

Densities of ethanol + water + cobalt(II) chloride mixtures have been measured with an oscillating-tube densimeter over a large range of concentrations of salt, at 298.15 K. From these densities, apparent molar volumes of the electrolyte in these mixtures have been calculated, and partial molar volumes at infinite dilution have been evaluated, at different concentrations of alcohol in the solvent.

Viscous Synergy of Pure Monoalcohol Mixtures in Water and Its Relation to Concentration

2004

Pure or aqueous alcohols are the solvents most widely used in industry, including in the manufacture of pharmaceuticals and cosmetic products. However, water–alcohol mixtures generate hydrogen-bonded molecular associations that lead to volume contraction and an increase in viscosity greater than that expected in the absence of any interaction between the components of the mixture. This phenomenon is referred to as viscous synergy. The present study investigates viscous synergy in monoalcohol systems containing up to five carbon atoms, since beyond hexanol all alcohols are practically insoluble in water. In all cases, determinations were made of the proportions of water and alcohol for which…