Optical radar measurements of the atmosphere

Optical radar investigations of atmosphere, and Mie scattering intensity functions for backscatte

Fernando SEBASTIÁN AGUILAR, Nueva Evangelización. Fe, cultura y política en la España de hoy, Ed. Encuentro, Madrid 1991, 302 pp. [RECENSIÓN]

\u3cp\u3eThe most recent JET campaign has focused on characterizing operation with the «ITER-like» wall. One of the questions that needed to be answered is whether the auxiliary heating methods do not lead to unacceptably high levels of impurity influx, preventing fusion-relevant operation. In view of its high single pass absorption, hydrogen minority fundamental cyclotron heating in a deuterium plasma was chosen as the reference wave heating scheme in the ion cyclotron domain of frequencies. The present paper discusses the plasma behavior as a function of the minority concentration X[H] in L-mode with up to 4MW of RF power. It was found that the tungsten concentration decreases by a factor of 4 when the minority concentration is increased from X[H] ≈ 5% to X[H] % 20% and that it remains at a similar level when X[H] is further increased to 30%; a monotonic decrease in Beryllium emission is simultaneously observed. The radiated power drops by a factor of 2 and reaches a minimum at X[H] ≈ 20%. It is discussed that poor single pass absorption at too high minority concentrations ultimately tailors the avoidance of the RF induced impurity influx. The edge density being different for different minority concentrations, it is argued that the impact ICRH has on the fate of heavy ions is not only a result of core (wave and transport) physics but also of edge dynamics and fueling.\u3c/p\u3

Oxidative stress and immunologic responses following a dietary exposure to PAHs in Mya arenaria

<p>Abstract</p> <p>Background</p> <p>The aim of this research was to investigate oxidative stress and immune responses following a dietary polycyclic aromatic hydrocarbon (PAH) exposure in a marine bioindicator organism, the soft shell clam, <it>Mya arenaria</it>. Immune parameters in hemolymph (haemocyte number, efficiency of phagocytosis and haemocyte activity) and assessment of oxidative stress using catalase (CAT) activity and levels of malondialdehyde (MDA) performed on the digestive gland were estimated as biomarkers in clams fed in mesocosm with PAH contaminated phytoplankton. MDA levels and CAT activities were also measured <it>in situ </it>in organisms sampled in a control site (Metis Beach, Québec, Canada) as well as organisms sampled in a site receiving domestic effluents (Pointe-au-Père, Québec, Canada), to assess effects of abiotic variables related to seasonal variations and mixed contamination on the selected parameters.</p> <p>Results</p> <p>Results on immune parameters suggest that the PAHs may interfere with the maturation and/or differentiation processes of haemocytes. MDA results showed that lipid peroxidation did not occur following the exposure. The levels of CAT activity corresponded to weak antioxidant activity (no significant differences). Recovery was noted for all the immune endpoints at the end of the experiment.</p> <p>Conclusion</p> <p>Results suggest that immune parameters are early biomarkers that can efficiently detect a physiological change during a short term exposure to low concentrations of PAHs. The <it>in situ </it>survey (in the natural environment) suggested that clams from the Pointe-au-Père site did not show any oxidative stress as well as the clams contaminated in mesocosm, probably due to the low concentrations of PAHs used for this study. MDA levels increased however in organisms from Metis Beach, a response probably related to domestic effluents or parasitism.</p

Role and management of soil biodiversity for food security and nutrition; where do we stand?

Soils host diverse communities that support and regulate ecosystem functions, thereby affecting plant production and resource use efficiencies. There is increasing evidence that agricultural intensification affects soil biodiversity (SBD) and such changes may impact on current and future food security. Here, we provide an overview of the state-of-the-art on the relations between agricultural management, SBD and food production. The potential of applying such knowledge to improve food security and nutrition is discussed. Biotechnological methods to describe impacts of agricultural practices on taxonomic and functional diversity of soil organisms are advancing rapidly. At the same time new understanding of soil-plant interactions has provided novel insights into the mechanisms by which soil organisms and plants co-regulate plant growth and defences, or affect food nutritional quality and safety. Yet, empirical studies on SBD – plant productivity relations often lead to results and applications that are crop and context specific. Translating knowledge on SBD into universally applicable soil management recommendations to enhance food production, and ultimately food security, remains challenging. Instead, we propose a holistic approach to SBD management that strengthens multiple ecosystem functions and provides ecological insurance.</p

Cationic porphyrin derivatives for application in photodynamic therapy of cancer

Current studies in photodynamic therapy (PDT) against cancer are focused on the development of new photosensitizers (PSs), with higher phototoxic action. The aim of this study was to compare the therapeutic efficiency of tri-cationic meso-substituted porphyrin derivatives (Tri-Py+–Me–PF, Tri-Py+–Me–Ph, Tri-Py+–Me–CO2Me and Tri-Py+–Me–CO2H) with the well-known tetra-cationic T4PM. The phototoxic action of these derivatives was assessed in human colon adenocarcinoma cells by cell viability, intracellular localization and nuclear morphology analysis. In the experimental conditions used we determined that after light activation –PF, –Ph and –CO2Me cause a more significant decline of cell viability compared to –CO2H and T4PM. These results suggest that the nature of the peripheral substituent influences the extent of cell photodamage. Moreover, we have demonstrated that PS concentration, physicochemical properties and further light activation determine the PDT response. All porphyrins were clearly localized as a punctuated pattern in the cytoplasm of the cells, and the PDT scheme resulted in apoptotic cell death after 3 h post-PDT. The tri-cationic porphyrin derivatives Tri-Py+–Me–PF, Tri-Py+–Me–Ph and Tri-Py+–Me–CO2Me showed a promising ability, making them good photosensitizer candidates for oncological PDT.Fil: Prack Mc Cormick, Bárbara Patricia. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Biología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Pansa, Maria Florencia. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Biología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Milla Sanabria, Laura Natalia. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Biología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Carvalho, Carla Marisa Brito. University of Aveiro; PortugalFil: Faustino, Maria Amparo Ferreira. University of Aveiro; PortugalFil: Neves, Maria Graça P. M. S.. University of Aveiro; PortugalFil: Cavaleiro, José A. S.. University of Aveiro; PortugalFil: Vittar, Natalia Belen Rumie. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Biología Molecular; ArgentinaFil: Rivarola, Viviana. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Biología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin