Search results for "PHOTOS"
showing 10 items of 701 documents
RbBr and CsBr doped with Eu2+ as new competitive X-ray storage phosphors
2001
Abstract After X-irradiation of the alkali halides RbBr and CsBr doped with divalent Eu a significant photostimulated luminescence (PSL) effect was found. In both systems the electron trap centre is an F centre, the hole trap centre is still unknown. The Eu 2+ aggregation with cation vacancies plays an important role. Although all of the different Eu 2+ aggregates seem to show PSL effects, they have different PSL efficiencies, decay times and spectral characteristics. In the case of RbBr:Eu 2+ it was possible to investigate the different Eu 2+ -cation vacancy aggregate states by magnetic circular dichroism of the optical absorption (MCDA) and MCDA-detected electron paramagnetic resonance. I…
Implication of pyoverdines in the interactions of fluorescent pseudomonads with soil microflora and plant in the rhizosphere
2007
Soils are known to be oligotrophic environments whereas soil microflora is mostly heterotrophic in such way that microbial growth in soil is mainly limited by the scarce sources of readily available organic compounds (Wardle 1992). Therefore, in soils, microflora is mostly in stasis (fungistasis/bacteriostasis) (Lockwood 1977). In counterpart, plants are autotrophic organisms responsible for the primary production resulting from the photosynthesis. A significant part of photosynthetates are released from plant roots to the soil through a process called rhizodeposition. These products, i.e. the rhizodeposits, are made of exudates, lysates, mucilage, secretions and dead cell material, as well…
Découverte des relations dans les réseaux sociaux
2011
In recent years, social network sites exploded in popularity and become an important part of the online activities on the web. This success is related to the various services/functionalities provided by each site (ranging from media sharing, tagging, blogging, and mainly to online social networking) pushing users to subscribe to several sites and consequently to create several social networks for different purposes and contexts (professional, private, etc.). Nevertheless, current tools and sites provide limited functionalities to organize and identify relationship types within and across social networks which is required in several scenarios such as enforcing users’ privacy, and enhancing t…
DNA Oxidation Photoinduced by Norharmane Rhenium(I) Polypyridyl Complexes: Effect of the Bidentate N,N′-Ligands on the Damage Profile
2018
Re(I)--polypyridyl complexes have interesting and distinctive photochemical and photosensitizing properties. This work describes the capability to induce (or photoinduce) DNA damage of three Re(I)-complexes with a naturally occurring alkaloid called norharmane (nHo) as ligand: [Re(CO)₃ (nHo)(L)]CF₃ SO₃ where L=2,2'-bipyridine (ReBpy), phenanthroline (RePhen) or dipyrido[3,2-a:2',3'-c]phenazine (ReDppz). The interaction of the complexes with DNA was investigated by steady-state and time-resolved spectroscopy. Data show that the mode and strength of interaction depend on the chemical structure of the bidentate ligand. The complexes show a major static contribution to the overall interaction, …
Squaraine Dyes for Photodynamic Therapy: Study of Their Cytotoxicity and Genotoxicity in Bacteria and Mammalian Cells¶‡
2007
Halogenated squaraine dyes are characterized by long wavelength absorption (>600 nm) and high triplet yields and therefore represent new types of photosensitizers that could be useful for photodynamic therapy. We have analyzed the cytotoxicity and genotoxicity of the bromo derivative 1, the iodo derivative 2 and the corresponding nonhalogenated dye 3 in the absence and presence of visible light. At concentrations of 1-2 microM, 1 and 2 reduced the cloning efficiency of AS52 Chinese hamster ovary cells to less than 1% under conditions that were well tolerated in the dark. Similarly, the proliferation of L5178Y mouse lymphoma cells was inhibited by photoexcited 1 and 2 with high selectivity. …
On the hybrid origin of the C2Salsola divaricata agg. (Amaranthaceae) from C3 and C4 parental lineages
2021
AbstractC2 photosynthesis is characterized by recapturing photorespiratory CO2 by RuBisCO in Kranz-like cells and is therefore physiologically intermediate between C3 and C4 photosynthesis. C2 can be interpreted as an evolutionary precursor of C4 and/or as the result of hybridization between a C3 and C4 lineage.We compared the expression of photosynthetic traits among populations of the Salsola divaricata agg. (C2) from humid subtropical to arid habitats on the coasts of the Canary Islands and Morocco and subjected them to salt and drought treatments. We screened for enhanced C4-like expression of traits related to habitat or treatment. We estimated species trees with a transcriptome datase…
Prototyping algorithm for retrieving FAPAR using MSG data in the context of the LSA SAF project
2007
This paper describes the prototyping algorithm developed for retrieving the Fraction of Absorbed Photosynthetically Active Radiation (FAPAR) using MSG data in the framework of satellite application facility on land surface analysis (LSA SAF). The prototyping relies on the Roujean and Breon (1995) method, which is based on simulations of visible and near infrared reflectance values in an optimal geometry. A relationship is found between a vegetation index and daily FAPAR The algorithm has been applied to one year of MSG BRDF data since August 2005, using a temporal frequency of 5-days, and then validated against a set of operational satellite FAPAR products such as MODIS, MERIS, SeaWiFS and …
Modeling seasonal branch carbon dynamics in pistachio as a function of crop load
2022
A simplified model for the prediction of carbon balance was developed to elucidate the seasonal trend of sink-source relationships in bearing and non-bearing pistachio (Pistacia vera L.) branches. Seasonal changes in growth rate of vegetative (leaf and shoot) and reproductive (infructescence) organs were monitored in branches of mature rainfed pistachio trees during the entire growing season (April–September). Simulations from the model were used to gain understanding of the implications of crop load on branch carbon (C) depletion and alternate bearing. Results showed that the pistachio branch was energetically able to sustain up to two infructescences (∼28 fruits) having a slightly positiv…
A simple, rapid extraction and assay procedure for the NAD+-dependent sorbitol dehydrogenase (SDH) in peach
1998
Sorbitol is the major photosynthetic product in peach. In sink tissues, sorbitol is converted to fructose via the NAD+-dependent sorbitol dehydrogenase (SDH). A new procedure is described that allows rapid, simple quantification of SDH activity in growing tissues. The procedure uses only 0.01 to 2.5 grams of fresh tissue per sample, such that a single shoot tip, a single root tip, or about 5 g of fruit flesh can be assayed for SDH activity. Storage of samples at 4 or -20 C° over night resulted in significant loss of enzyme activity. Thus, freshly harvested tissues were ground with sand in buffer at 2°C in a mortar and pestle, and the homogenate centrifuged @ 3000 ´ g to remove particulate m…
Relationship between tree water status and physiology, yield, and fruit quality in the table olive (Olea europaea sativa L.) cultivar ‘Nocellara del …
2012
Although the olive (Olea europaea sativa l.) is considered a xerophytic species, long periods of water stress and high temperatures during summer months can greatly affect plant physiology and productivity. In recent years, the use of plant-based water status indicators have become popular in the study of plant-water relationships and in the design of irrigation programs, particularly midday stem water potential (ψstem). The current trend in the irrigation of olive trees is in the development of Deficit Irrigation (DI) systems whereby the water is applied at a rate which is lower than evapotranspiration needs, resulting in only very small reductions in yield. Rather than working towards min…