Search results for "Indicator"

FIA-fluorimetric determination of thiamine.

1990

A flow injection-fluorimetric determination of thiamine is reported. The procedure is based on the oxidation of the analyte with potassium hexacyanoferrate(III) immobilized on an anionic exchange resin; the fluorescence is monitored in aqueous basic solution. Concentrations of the vitamin of 0.1-4 ppm have been determined; the relative standard deviation was 1.8%. The injection rate was 28 samples/h. The influence of other substances and the determination of the drug in a pharmaceutical formulation are also reported.

alpha-Tocopherol, MDA-HNE and 8-OHdG levels in liver and heart mitochondria of adriamycin-treated rats fed with alcohol-free beer.

2008

Different studies indicate that oxidative stress and mitochondrial damage are key factors in different pathogenic process. The aim of this study was to investigate the possible protective role of alcohol-free beer on adriamycin-induced (ADR) heart and liver toxicity using biomarkers of oxidative stress. This effect was compared with the effect of alcohol beer intake and with a control group. Rats were randomly divided into six groups. The first group received no adriamycin, was fed with water and was regarded as the control group; the second group was injected with a ADR (two cycles of 5mg/kg); the third and fourth groups were fed with alcohol-free and beer for 21 days, respectively and the…

Long-term recovery of stream habitat structure and benthic invertebrate communities from in-stream restoration

2002

Headwater streams channelized for water transport of timber in Finland are being restored to their pre-channelization state. The primary motivation is the enhancement of sport fisheries, but restoration probably has profound impacts also on other stream organisms. We assessed how such ‘‘single-goal’’ restorations affect benthic macroinvertebrate communities. We revisited the streams sampled by Laasonen et al. [Aquatic Conservation: Marine and Freshwater Ecosystems 8 (1998)] in the early 1990s when the streams had been recently restored. In 1997, the recovery period of these streams ranged from 4 to 8 years. Habitat structure among the stream types represented a distinct recovery gradient, w…

Assessment and mapping the sensitive areas to desertification in an insular Sahelian mountain region Case study of the Ribeira Seca Watershed, Santia…

2015

10 pages; International audience; This paper presents the assessment and mapping of the Ribeira Seca catchment, an insular Sahelian mountain region sensitive to desertification, located on the island of Santiago, Cabo Verde. Desertification is a threat to the global environment, representing a serious ecological problem in Cabo Verde. To successfully combat desertification, an evaluation of desertification consequences is required and the building of cartography of the sensitivity for arid and semi-arid ecosystems is required as a first step. The MEDALUS model was the basis for this study in which six quality indicators were used: climate, soil, vegetation, land management, erosion and soci…

Determination of 5-nitrofurylacrylic acid in wines by high-performance liquid chromatography

1988

Peak dispersion in gradient elution: An insight based on the plate model.

2020

Gradient elution in liquid chromatography reduces the analysis time, improves the efficiency and increases the peak capacity. The study of this chromatographic mode has been based mainly on kinetic dispersion models. The plate model has been applied to a lesser extent, despite being the basis for the concepts of plate height and chromatographic efficiency. In this work, a general equation describing peak dispersion in HPLC gradient elution is derived from the plate model. This equation is studied and validated for three types of gradients: (i) a reference gradient without ramp in which the retention factor varies with time identically throughout the column, (ii) a gradient of stationary pha…

Preparation of ferulic acid derivatives and evaluation of their xanthine oxidase inhibition activity.

2007

Several ferulic acid ethyl esters (3a-h) were synthesized under the Knoevengel reaction condition and they were further reduced to afford the respective allylic alcohol derivatives (4a-g). Some of them were evaluated for the xanthine oxidase (XO) inhibitory activity. Among them, 3h exhibited a significant inhibitory activity with an IC50 value of 1.35 x 10(-5) M, while the IC50 value of allopurinol used as the positive control was 1.49 x 10(-5) M. The study suggested that the higher acidity of the phenolic OH group in the ferulic acid derivatives might result in improved XO inhibitory activity.

Risk indicators with several lines of business: comparison, asymptotic behavior and applications to optimal reserve allocation

2013

International audience; In a multi-dimensional risk model with dependent lines of business, we propose to allocate capital with respect to the minimization of some risk indicators. These indicators are sums of expected penalties due to the insolvency of a branch while the global reserve is either positive or negative. Explicit formulas in the case of two branches are obtained for several models independent exponential, correlated Pareto). The asymptotic behavior (as the initial capital goes to infinity) is studied. For higher dimension and several periods, no explicit expression is available. Using a stochastic algorithm, we get estimations of the allocation, compare the different allocatio…

Natural soil reservoirs for human pathogenic and fecal indicator bacteria

2015

Prod ? EA UB INRA BIOME; International audience; résumé du livre : Environmental microbiology, the study of the roles that microbes play in all planetary environments, is one of the most important areas of scientific research. The The Manual of Environmental Microbiology, Fourth Edition, provides comprehensive coverage of this critical and growing field. Thoroughly updated and revised, the Manuall is the definitive reference for information on microbes in air, water, and soil and their impact on human health and welfare. Written in accessible, clear prose, the manual covers four broad areas: general methodologies, environmental public health microbiology, microbial ecology, and biodegradati…

Variations spatiales et temporelles de communautés adventices des cultures annuelles en France

2010

Résumé de thèse; National audience