Search results for "ROMA"
showing 10 items of 13919 documents
Optimization of selenium determination in human milk and whole blood by flow injection hydride atomic absorption spectrometry.
1998
abstract A flow injection hydride atomic absorption spectrometry (FI-HAAS) method was developed for determining selenium in human milk and whole blood after microwave digestion of the sample. The sample (2 mL human milk or 0.25 mL blood) was introduced into the microwave vessel with 1.5 mL HN03 and 0.25 mL H202 and 300 W (4 min) and 600 W (4 min) were applied. The digestion was completed by heating to 140 C (2-3 h). Se (VI) was reduced to Se (IV) with hydrochloric acid. The instrumental conditions for FI-HAAS (concentrations of reducing agent and carrier acid, flow rate of argon carrier gas, and sample volume injected) were optimized. The detection limit of the proposed method was 0.23 ng/m…
L’anamorphose du roman : les distorsions de la perspective dans "la Disparition" de Georges Perec
2007
L’anamorphose apparaît en application aux arts plastiques et se traduit par le bouleversement du point de vue habituel. Cette distorsion visuelle, en créant le caractère énigmatique de l’œuvre, vise à la déstabilisation du spectateur qui, sollicité par les formes, participe de la pluralité de la vision et de la démultiplication des possibles interprétatifs. Cette relativité de la place du spectateur permet la migration du concept d’anamorphose au domaine littéraire et son application en tant que pratique de création ou, plutôt, de réception : L’anamorphose […] procède par une intervention des éléments et des fonctions. Au lieu d’une réduction progressive à leurs limites visibles, c’est une …
Anaphylatoxin-like molecules generated during complement activation induce a dramatic enhancement of particle uptake in rainbow trout phagocytes.
2004
Here we have identified a serum fraction containing approximately 8-kDa molecules with an unexpected capacity to greatly enhance particle uptake in trout head kidney leukocytes (HKLs). This approximately 8-kDa particle-uptake enhancing fraction (PUEF-8) was purified from complement-activated serum by gel filtration chromatography. Mass spectrometric analysis and reactivity of anti-trout C3-1 and C4 antibodies, indicated the presence of C3a, C4a and C5a molecules in PUEF-8. Using a newly developed flow cytometric assay that measures the capacity of cells to ingest fluorescent beads, we showed that PUEF-8 induced a striking enhancement (344+/-50% higher than the PBS control value) in the numb…
Clean analytical method for the determination of propoxur
1995
Abstract A method has been developed for the determination of propoxur, a carbamate pesticide, by means of its reaction with p-aminophenol (PAP). The method involves the reaction, in the presence of KIO4, between the quinoneimine form of PAP and the deprotonated form of 2-isopropoxyphenol, obtained by the alkaline hydrolysis of propoxur, to provide an indophenol dye which absorbs at 600 nm. The analysis is carried out in a flow system and, after the measurement step, the waste, the reaction product and the unreacted derivatising agent is detoxified in a UV-irradiated coil placed after the measurement flow-cell and after mixing the waste with a TiO2(anatase) catalyst slurry, which can be reu…
Photocatalytic degradation of carbaryl in aqueous TiO2 suspensions containing surfactants
1999
The effect of ionic and non-ionic aliphatic surfactants on the photocatalytic degradation of Carbaryl (1-naphtyl-N-methylcarbamate) in aqueous solutions containing suspended TiO2 (anatase) particles, under irradiation with simulated AM1 solar light, was investigated. A neat inhibitory effect on the degradation rate was observed, depending on the nature of the surfactant and on the initial pH of the solution. The decay profiles of the primary process corresponded to the usual pseudo-first order kinetics for surfactant concentrations below the critical micellar concentration range, whereas a more complicate behaviour was observed in the presence of micellar aggregates. Mineralization of the p…
Photon absorption by aqueous TiO2 dispersion contained in a stirred photoreactor
1991
We present a simple experimental method which allows the evaluation of the absorbed photon flow. The method is based on measurements of transmitted photon rates (by means of standard actinometer solutions) for different reactor thicknesses and/or catalyst concentrations. The method was applied to phenol degradation reaction carried out in a stirred batch phtotoreactor containing aqueous TiO 2 (anatase) dispersion, directly irradied by a 1,500 W Xe lamp
Rate of photon absorption and turnover number: two parameters for the comparison of heterogeneous photocatalytic systems in a quantitative way
1993
Abstract In order to correctly compare the performance of different photocatalytic systems using polycrystalline semiconductor oxides, two parameters are proposed: the rate of photon absorption (rpa) and the turnover number (tn). From these quantities the quantum yield (qy), which indicates the efficiency of the absorbed photons for promoting a reaction event, can be determined. The phenol photodegradation reaction, carried out in aqueous dispersions of polycrystalline TiO2 (anatase) of different preparation methods and sources, has been used as “test reaction” in order to determine the tn, rpa and qy values.
ChemInform Abstract: Rate of Photon Absorption and Turnover Number: Two Parameters for the Comparison of Heterogeneous Photocatalytic Systems in a Qu…
2010
Abstract In order to correctly compare the performance of different photocatalytic systems using polycrystalline semiconductor oxides, two parameters are proposed: the rate of photon absorption (rpa) and the turnover number (tn). From these quantities the quantum yield (qy), which indicates the efficiency of the absorbed photons for promoting a reaction event, can be determined. The phenol photodegradation reaction, carried out in aqueous dispersions of polycrystalline TiO2 (anatase) of different preparation methods and sources, has been used as “test reaction” in order to determine the tn, rpa and qy values.
Découverte d'un ex-voto particulier sur le site cultuel d'Essarois (Côte-d'Or) : un cas de polydactylie chez les Gallo-Romains ?
2011
During geo-archaeological research on the slope where the source associated with the Essarois (Côte-d'Or) cult site is located, in the locality of La Cave, an anatomic votive offering of a human foot was discovered in the alluvial sedimentary deposits. Carved from local oolitic limestone, it is rather crude in appearance but it is possible to make out that it has the unusual number of six toes. Although it may have been a blunder or the result of negligence by the sculptor, the phenomenon may equally have been a deliberate representation of a case of polydactyly, a malformation that was known in Antiquity.
Inhibition of Histone Deacetylase Activity in Human Endometrial Stromal Cells Promotes Extracellular Matrix Remodelling and Limits Embryo Invasion
2011
Invasion of the trophoblast into the maternal decidua is regulated by both the trophoectoderm and the endometrial stroma, and entails the action of tissue remodeling enzymes. Trophoblast invasion requires the action of metalloproteinases (MMPs) to degrade extracellular matrix (ECM) proteins and in turn, decidual cells express tissue inhibitors of MMPs (TIMPs). The balance between these promoting and restraining factors is a key event for the successful outcome of pregnancy. Gene expression is post-transcriptionally regulated by histone deacetylases (HDACs) that unpacks condensed chromatin activating gene expression. In this study we analyze the effect of histone acetylation on the expressio…