Rapid quantitative detection of Yersinia pestis by lateral-flow immunoassay and up-converting phosphor technology-based biosensor

Up-converting phosphor technology (UPT)-based lateral-flow immunoassay has been developed for quantitative detection of Yersinia pestis rapidly and specifically. In this assay, 400 nm up-converting phosphor particles were used as the reporter. A sandwich immumoassay was employed by using a polyclonal antibody against F1 antigen of Y. pestis immobilized on the nitrocellulose membrane and the same antibody conjugated to the UPT particles. The signal detection of the strips was performed by the UPT-based biosensor that could provide a 980 nm IR laser to excite the phosphor particles, then collect the visible luminescence emitted by the UPT particles and finally convert it to the voltage as a signal. V-T and V-c stand for the multiplied voltage units for the test and the control line, respectively, and the ratio V-T/V-C is directly proportional to the number of Y pestis in a sample. We observed a good linearity between the ratio and log CFU/ml of Y pestis above the detection limit, which was approximately 10(4) CFU/mI. The precision of the intra- and inter-assay was below 15% (coefficient of variation, CV). Cross-reactivity with related Gram-negative enteric bacteria was not found. The UPT-LF immunoassay system presented here takes less than 30 min to perform from the sample treatment to the data analysis. The current paper includes only preliminary data concerning the biomedical aspects of the assay, but is more concentrated on the technical details of establishing a rapid manual assay using a state-of-the-art label chemistry. (c) 2006 Elsevier B.V. All rights reserved.

Étude quantitative de l'upwelling sur le plateau continental ivorien

A wind-driven upwelling occurs on the continental shelf of Ivory Coast during the northern summer months; by studying the average conditions in the wind field, it has been found that in steady state the vertical speed upwards does not exceed 70 cm per day. The vertical flow per km super(2) is estimated in 46 m super(3)/s for a channel 50 m depth and in 92m super(3)/s for a channel 300 m depth. This study does not include the inclination of isopycnes in geostrophic adjustment with the variations of the Guinea current.

Qualitative and quantitative aspects of the food of Ethmalosa fimbriata (Bowdich) in the Ebrié lagoon (Côte d'Ivoire)

The food of Ethmalosa fimbriata in the central part of the Ebrié lagoon, where the salinity is low, consists on limnic phytoplankton. In the region near Abidjan, which is more strongly influenced by coastal water, it consists of marine phyto- and zooplankton. The daily ration of a 12.5 cm fork-length fish is estimated to be between 2 and 3 % of its body weight.

The calibration of a semi-quantitative approach to fish stock assessment in the North West Region of the NRA

(1) A total of 45 sites was sampled, each being fished using the semi-quantitative and quantitative techniques. (2) A significant relationship existed between the semi-quantitative and Quantitative results for all age groups of salmonids (R2 83.4% to 96.1%, p < 0.0001). (3) The results from each site were categorised according to an existing classification system for quantitative and semi-quantitative data. The semi-quantitative component of this system was modified using the results of this investigation. The degree of error associated with sites classified semi-quantitatively was found to be slightly less when using the modified system for 0+ salmon, > 0+ salmon and 0+ trout, ranging from 10.5% to 30%. (4) Insufficient data points were available for the analysis of coarse fish data.

Analysis of multivariate stochastic signals sampled by on-line particle analyzers: Application to the quantitative assessment of occupational exposure to NOAA in multisource industrial scenarios (MSIS)

In multisource industrial scenarios (MSIS) coexist NOAA generating activities with other productive sources of airborne particles, such as parallel processes of manufacturing or electrical and diesel machinery. A distinctive characteristic of MSIS is the spatially complex distribution of aerosol sources, as well as their potential differences in dynamics, due to the feasibility of multi-task configuration at a given time. Thus, the background signal is expected to challenge the aerosol analyzers at a probably wide range of concentrations and size distributions, depending of the multisource configuration at a given time. Monitoring and prediction by using statistical analysis of time series captured by on-line particle analyzers in industrial scenarios, have been proven to be feasible in predicting PNC evolution provided a given quality of net signals (difference between signal at source and background). However the analysis and modelling of non-consistent time series, influenced by low levels of SNR (Signal-Noise Ratio) could build a misleading basis for decision making. In this context, this work explores the use of stochastic models based on ARIMA methodology to monitor and predict exposure values (PNC). The study was carried out in a MSIS where an case study focused on the manufacture of perforated tablets of nano-TiO2 by cold pressing was performed