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Biomedical subjects

R Prioli

Publications and source records attributed to R Prioli.

6 recordsLinked to original sources
PubMed2000

Grain size distribution analysis in polycrystalline LiF thin films by mathematical morphology techniques on AFM images and X-ray diffraction data.

The influence of the deposition temperature on the grain size of polycrystalline lithium fluoride (LiF) thin films is studied using a mathematical morphology method. On atomic force microscopy images of the LiF surface, the grain sizes and shapes are determined by applying the watershed technique, together with a shape factor algorithm. Also, the domain size of the film structure, determined by an X-ray diffraction data analysis, is compared and correlated with the mean grain size as a function of the deposition temperature. In both cases a linear increase with temperature and a very good agreement among the two structural parameters (grain and domain size) was found.

Journal Article↗
PubMed1999

Quantification of deoxynivalenol in wheat using an immunoaffinity column and liquid chromatography.

A simple and accurate method to quantify the mycotoxin deoxynivalenol (DON) in wheat is described. The method uses immunoaffinity chromatography for DON isolation and liquid chromatography (LC) for toxin detection and quantification. Wheat samples are extracted in water, filtered twice and applied to an immunoaffinity column. Following a water wash, DON is eluted from the column with methanol and injected onto an LC system with a UV detector for quantification. Test performance was evaluated in terms of antibody specificity, limit of detection, percentage recovery, precision, column capacity, assay linearity and comparison with the GC-electron-capture detection (ECD) method of Tacke and Casper. Specificity of the immunoaffinity column cleanup procedure was confirmed with only DON (>80%) and its 15-C derivatives (40-50%) being recognized by the antibody while 3-C DON derivatives, nivalenol, T-2 and fusarenon-X did not bind. The limit of detection is at least 0.10 microg/g. Percentage recovery for the entire assay range averages 90% with an average relative standard deviation of 8.3%. Naturally contaminated samples showed comparable precision. Column capacity was determined to be 3.3 microg. The assay showed a high degree of linearity (r2=0.999) and an optimum assay range of 0.10 to 10.0 microg/g. Comparative analysis of 28 naturally or artificially contaminated wheat samples using DONtest-HPLC and the GC-ECD method of Tacke and Casper showed that DONtest-HPLC is a statistically significant predictor of the GC-ECD method (r2=0.982).

Antibody Specificity↗
PubMed1998

Improved fluorometric and chromatographic methods for the quantification of fumonisins B(1), B(2) and B(3).

Fumonisins pose serious health risks to humans and livestock, making their detection imperative in foods and feedstuffs. This detection can be accomplished quickly, precisely and accurately in a two-step chromatographic process. In the first step, fumonisins are extracted from a sample and isolated on an immunoaffinity column. In the second step, fumonisins are converted to fluorescent derivatives and quantified either through high-performance liquid chromatography (HPLC) or by fluorometer. These methods offer significant improvements in performance compared to earlier technology: limits of detection as low as 0.016 micrograms/g with HPLC-based detection and 0.25 micrograms/g for fluorometer-based detection; greater assay linearity (with HPLC, r = 0.997; with fluorometer, r = 0.998); larger immunoaffinity column capacity (77% recovery at 12.5 micrograms) and extended assay range (0-10 micrograms/g) for methods. The percentage recovery of fumonisins over the entire assay range averaged 83% for both the fluorometer and HPLC methods. Precision studies were performed for both the fluorometer and the HPLC methods. The average coefficient of variation was 14% for the fluorometer method and 8.3% for the HPLC method. As a result of the efficient separation, the improved HPLC method offers the advantage of precise individual quantification of FB1, FB2 and FB3. The two methods were compared using 33 naturally or artificially contaminated corn samples. Linear regression analysis demonstrated an excellent correlation (r = 0.996) between the two techniques. Higher recoveries of fumonisins were obtained using this HPLC method than with the official AOAC method.

Carboxylic Acids↗
PubMedDate not supplied

Lateral force microscopy profiles for amorphous potentials.

In this work, the lateral force profiles of the scanning force microscope tip on an amorphous surface were simulated with the use of an independent oscillator model. The correlation between the lateral force profiles and the surface potential were studied as a function of the tip-surface normal force and relative scanning velocity. It is shown that the microscope resolution is governed by the quotient between the average potential interaction energy and the average elastic energy stored before the jumps. We show that there is an optimal velocity with which the scanning tip better senses the surface potential and we present its scaling laws.

Journal Article↗
PubMedDate not supplied

Rapid immunoaffinity-based method for determination of zearalenone in corn by fluorometry and liquid chromatography.

An immunoaffinity-based method was developed to determine zearalenone in corn. Corn samples were extracted in acetonitrile-water (90 + 10, v/v), applied to an immunoaffinity column, and eluted with methanol. The isolated toxin was quantitated either by reaction with aluminum chloride hexahydrate (AlCl3.6H2O) prior to measurement with a fluorometer or injection into a liquid chromatographic (LC) system with a fluorescence detector. Performance was evaluated in terms of antibody specificity, limit of detection, percentage recovery, precision, column capacity, assay linearity, and comparison with AOAC Official Method 985.18. With the immunoaffinity column cleanup procedure, only zearalenone and its metabolites were recognized by the antibody (> or = 75% recovery). Limits of detection were 0.10 microgram/g for the fluorometer and 0.10 or 0.0025 microgram/g (sensitive method) for the LC method. Percentage recovery averaged 105% (fluorometer) and 93% (LC method), with average relative standard deviations (RSDs) of 15.7 and 9.3%. Naturally contaminated samples gave comparable RSDs of 8.3 and 9.9% for the fluorometer and LC methods, respectively. Column capacity was 4.0 micrograms with 89% recovery. Assay linearity was comparable for both methods (r2 = 0.998). Optimum assay ranges were 0.10-5.0 micrograms/g for the fluorometer and 0.10-50 or 0.0025-5.0 micrograms/g (sensitive method) for the LC method. Comparative analysis of 17 naturally contaminated corn samples using Zearala Test LC and the official AOAC LC method for detection of zearalenone showed that Zearala Test is statistically comparable to the AOAC Official Method 985.18 (r2 = 0.747).

Antibody Specificity↗