Search results for "fusion"
showing 10 items of 4513 documents
The ultrastructure of multinucleate giant cells
2002
Abstract A survey of the available ultrastructural data on physiologically and pathologically occurring and virally-induced multinucleate giant cells (MNGCs) is presented. Emphasis is initially placed upon the bone osteoclast, the skeletal muscle myotube and the placental syncytiotrophoblast. The widespread occurence of MNGCs in a range of pathological situations is discussed, with emphasis upon the broad involvement of the macrophage in inflammatory responses. Many viruses produce cell fusion in vivo and in vitro when cell cultures are infected. Several examples are given. A clear distinction is drawn between viral fusion from “without” and viral fusion from “within” the cell. The cytopath…
Validity of NMR pore-size analysis of cultutal heritage ancient building materials containing magnetic impurities
2007
NMR relaxation time distributions, obtained with laboratory and portable devices, are utilized to characterize the pore-size distributions of building materials coming from the Roman remains of the Greek-Roman Theatre of Taormina. To validate the interpretation of relaxation data in terms of pore-size distribution, comparison of results from standard and in situ NMR experiments with results of the mercury intrusion porosimetry (MIP) has been made. Although the pore-size distributions can be obtained by NMR in terms of either longitudinal (T-1) or transverse (T-2) relaxation times distributions, the shorter duration of the T-2 measurement makes it, in principle, preferable, although the dete…
PI-Extension of porphyrins via intramolecular aromatic oxidative C-N coupling
2019
Π-extension of porphyrins has been performed via intramolecular oxidative C-N coupling of peripheral pyridinyl fragment(s) with the porphyrin core. These fusion reactions lead to the formation of C-N bond(s) between the substituent(s) and the porphyrin. The precursors were functionnalized with 2-mercaptopyridine, 8-hydoxyquinoline and 2-picoline at their meso or β-pyrrolic positions via aromatic nucleophlic substitution, cross-coupling reaction or reaction of the macrocycle with organolithium reagents. Voltametric analyses revealed some marked differences on the reactivity of the porphyrins depending on their substitution pattern and metalation (nickel(II) or zinc(II)). Chemical and electro…
Review of gas diffusion cathodes for alkaline fuel cells
2009
Abstract This paper gives a technical background to alkaline fuel cells (AFCs), introducing the advantages and drawbacks of the technology. AFCs offer the potential for low cost, mass producible fuel cells, without the dependency on platinum based catalysts and (currently) expensive membrane electrolytes. The AFC uses relatively low cost electrolytes based on aqueous bases such as potassium hydroxide. The inherent CO 2 sensitivity of the electrolyte can be addressed by filtering out the CO 2 from the air intake using a simple scrubber and periodically replacing the liquid electrolyte. A review of the state-of-the-art in gas diffusion cathode development is given. The overall cell performanc…
Semi-empirical defect calculations for the perovskite KNbO3
2000
A new parametrization of the classical shell model for the cubic phase of the perovskite KNbO3 has been derived and used to calculate the structural, elastic and dielectric properties of this material. Using this parametrization, the defect formation and migration energies, as well as atomic displacements, have been calculated. In parallel, the quantum mechanical method of the intermediate neglect of the differential overlap (INDO) has been applied to the same problem. The migration energies for the O vacancy obtained by these quite different methods are reasonably close (0.68 eV and 0.79 eV, respectively) and also agree with the only experimental estimate available of approximately 1 eV. A…
On the influence of the supporting frame on the nuclear response of the Helium-Cooled Lithium Lead Test Blanket Module for ITER
2006
Abstract Within the European Fusion Technology Programme, very intense research activities have been promoted on the Helium-Cooled Lithium Lead (HCLL) breeding blanket concept with the specific aim of manufacturing a Test Blanket Module (TBM) to be irradiated in ITER. HCLL-TBM is foreseen to be located in an ITER equatorial port, being housed inside a proper steel-supporting frame. In particular, since that frame has been designed to provide two cavities separated by a dividing plate and HCLL-TBM is foreseen to fill just one of them, its nuclear response could vary accordingly to the filling status of the other one, unless the dividing plate is thick enough to isolate the components housed …
Feasibility of D-D start-up under realistic technological assumptions for EU-DEMO
2021
Abstract One of the main issues in view of the realization of a DEMOnstration fusion reactor is the availability of a sufficient external supply of tritium (T) to start operation. T is an unstable nuclide, which is almost absent in nature and is currently available as by-product in e.g. CANDU, whose operation in the next decades (both in terms of life extension of existing reactors and construction of new ones) is at the moment under debate. During DEMO operation, T will be generated on-site by breeding blanket, employing the neutrons originating from D-T reaction. However, it is considered that a certain initial amount of T is needed to start operation, the so-called start-up inventory. An…
Linear instability of the vertical throughflow in a horizontal porous layer saturated by a power-law fluid
2016
Abstract The effects of the vertical throughflow of a non-Newtonian power-law fluid on the onset of convective instability in a horizontal porous layer are investigated. The extended Darcy’s model of momentum diffusion is employed together with the Oberbeck–Boussinesq approximation. A stationary basic solution for the vertical throughflow is determined analytically. The basic velocity and temperature fields turn out to be independent of the non-Newtonian rheology. A linear stability analysis is carried out, leading to a fourth-order eigenvalue problem. A numerical solution of the eigenvalue problem is employed to obtain the neutral stability curves and the critical Rayleigh number for the o…
The appropriate and justified use of medical radiation in cardiovascular imaging: a position document of the ESC Associations of Cardiovascular Imagi…
2014
The benefits of cardiac imaging are immense, and modern medicine requires the extensive and versatile use of a variety of cardiac imaging techniques. Cardiologists are responsible for a large part of the radiation exposures every person gets per year from all medical sources. Therefore, they have a particular responsibility to avoid unjustified and non-optimized use of radiation, but sometimes are imperfectly aware of the radiological dose of the examination they prescribe or practice. This position paper aims to summarize the current knowledge on radiation effective doses (and risks) related to cardiac imaging procedures. We have reviewed the literature on radiation doses, which can range …
Application of White Mustard Bran and Flour on Bread as Natural Preservative Agents.
2021
In this study, the antifungal activity of white mustard bran (MB), a by-product of mustard (Sinapis alba) milling, and white mustard seed flour (MF) was tested against mycotoxigenic fungi in the agar diffusion method. The results obtained were posteriorly confirmed in a quantitative test, determining the minimum concentration of extract that inhibits the fungal growth (MIC) and the minimum concentration with fungicidal activity (MFC). Since MF demonstrated no antifungal activity, the MB was stored under different temperature conditions and storage time to determine its antifungal stability. Finally, an in situ assay was carried out, applying the MB as a natural ingredient into the dough to …