Sampling hazelnuts for aflatoxin: effect of sample size and accept/reject limit on reducing the risk of misclassifying lots

About 100 countries have established regulatory limits for aflatoxin in food and feeds. Because these limits vary widely among regulating countries, the Codex Committee on Food Additives and Contaminants began work in 2004 to harmonize aflatoxin limits and sampling plans for aflatoxin in almonds, pistachios, hazelnuts, and Brazil nuts. Studies were developed to measure the uncertainty and distribution among replicated sample aflatoxin test results taken from aflatoxin-contaminated treenut lots. The uncertainty and distribution information is used to develop a model that can evaluate the performance (risk of misclassifying lots) of aflatoxin sampling plan designs for treenuts. Once the performance of aflatoxin sampling plans can be predicted, they can be designed to reduce the risks of misclassifying lots traded in either the domestic or export markets. A method was developed to evaluate the performance of sampling plans designed to detect aflatoxin in hazelnuts lots. Twenty hazelnut lots with varying levels of contamination were sampled according to an experimental protocol where 16 test samples were taken from each lot. The observed aflatoxin distribution among the 16 aflatoxin sample test results was compared to lognormal, compound gamma, and negative binomial distributions. The negative binomial distribution was selected to model aflatoxin distribution among sample test results because it gave acceptable fits to observed distributions among sample test results taken from a wide range of lot concentrations. Using the negative binomial distribution, computer models were developed to calculate operating characteristic curves for specific aflatoxin sampling plan designs. The effect of sample size and accept/reject limits on the chances of rejecting good lots (sellers' risk) and accepting bad lots (buyers' risk) was demonstrated for various sampling plan designs.     

Syntheses,Spectral, Thermal and Structural Characterization of 2‐Phenyl‐2‐(1‐hydroxyiminoethyl)‐1,2,3,4‐tetrahydroquinazoline and Its Novel Nickel(II) Complex

The 2‐phenyl‐2‐(1‐hydroxyiminoethyl)‐1,2,3,4‐tetrahydroquinazoline (HL) and its Ni^II complex have been prepared and characterized by spectral method (FT‐IR, NMR (¹³C and ¹H), UV‐vis.), elemental analysis, magnetic susceptibility and thermal analysis (TG, DTA) techniques. The crystal structures of HL and Ni^II complex were also determined by the single crystal X‐ray diffraction. The HL and Ni^II complex crystallizes in the monoclinic and triclinic, space groups P2₁/c and , respectively. The complex was occurred by the elimination of 1 mole of 2‐aminobenzylamine from the 2 moles of the HL after the ring opening reaction by the Ni^II attack. Crystallographic study reveal that Ni^II atom has a square planer geometry being coordinated by four nitrogen atoms of HL. Two thermal processes of the HL and Ni^II complex can occur in TG and DTA curves.     

Dissolution kinetics of copper(II) oxide in water saturated by sulphur dioxide

The dissolution and the kinetics of dissolution of cooper(II) oxide in water saturated by sulphur dioxide has been studied. In the experiments, the particle size, the flow rate of the gas, the solid to liquid ratio, and the reaction temperature have been chosen as parameters, while the stirring rate was held constant. As a result of present experiments, it was observed that the decrease of the particle size, the solid to liquid ratio, and an increase of the reaction temperature increased the dissolution rate. It was also observed that the flow rate of sulphur dioxide in the range of its flow rate values did not affect the dissolution rate. The reaction kinetics of copper(II) oxide according to the heterogeneous reaction models was examined and it was found that the dissolution rate was controlled by chemical reaction. The calculated activation energy is 66.50 kJmol^?1. © 1994 John Wiley & Sons, Inc.     

Chemical effect on total mass attenuation coefficients of V, Cr, Mn, Co and Ni

Detailed interpretation of data obtained from X-ray transmission measurements usually depends on the assumption that the contribution of each element is additive. This assumption yields the mixture rule for X-ray attenuation coefficients which is valid if molecular and chemical effects are negligible. We measured the total mass attenuation coefficients of V, Cr, Mn, Co and Ni in various their compounds. Absorption corrections were carried on data for ligands in the compounds. We found that V, Cr, Mn, Co and Ni have different total mass attenuation coefficients in the different compounds. We compared our results with theoretical values of Hubbell and Seltzer.     

Synthesis,Structure, DFT Calculations,and In Silico Toxic Potential of Ni(II), Zn(II), and Fe(II) Complexes with a Tridentate Schiff Base

Russian Journal of General Chemistry - The Schiff base ligand has been synthesized from 5-bromo-2-hydroxybenzaldehyde and ethyl...     

A novel polyphosphazene with nitroxide radical side groups as cathode‐active material in Li‐ion batteries

A novel polyphosphazene carrying stable nitroxide aromatic radical groups as a pendant with four electrons involvement per repeating unit is synthesized. To do so, series of macromolecular substitution reactions of poly (dichlorophosphazene) with 3,5‐dibromophenol, 2‐methyl‐2‐nitrosopropane, and lead oxide, respectively, are performed. After characterization of the newly synthesized polymers by standard spectroscopic techniques (such as Fourier transform infrared [FT‐IR], nuclear magnetic resonance [NMR], or electron paramagnetic resonance [EPR]), the targeted polymer is further investigated as a cathode‐active material for rechargeable lithium‐ion batteries (LIBs). The cell delivered a good rate performance with a discharge capacity of 100 mAh/g at a C/2 current density over 500 cycles.     

Dehydration kinetics of ulexite from thermogravimetric data

In the present study, the kinetic parameters of the thermal decomposition of ulexite were investigated by using TGA data. For the kinetic analysis, the Suzuki and Coats-Redfern methods were applied. It was determined that the process fits a first-order kinetic model, and the value of the activation energies and frequency factors decreased with decreasing particle size, which can be attributed to the increasing particle internal resistance to the escape of water as the grain size increases. The activation energy values were found to be 47.34–60.01 kJ mol^–1 for region I and 0.225–1.796 kJ mol^–1 for region II for the range of particle size fraction used. The frequency factors were calculated to be 9821.8–524.9 s^–1 for region I and 3.05×10^–44–2.807×10^–5 for region II for the same conditions.     

Investigation of radiosterilization feasibility of sulfamethoxazole by ESR spectroscopy

In the present study, the spectroscopic features of the radiolytic intermediates that were produced in gamma-irradiated (5, 10, 25 and 50?kGy) sulfamethoxazole (SMX) have been investigated by electron spin resonance (ESR) spectroscopy and the radiation sterilization feasibility of SMX by ionizing radiation was examined. Gamma-irradiated SMX exhibited a complex ESR spectrum consisting of 13 resonance lines where spectral parameters for the central resonance line were found to be g?=?2.0062 and ΔH_pp?=?0.6?mT. The radiation yield of SMX was calculated to be relatively low (G?=?0.1) by ESR spectroscopy and no meaningful difference was observed in the comparison of unirradiated and 50?kGy gamma irradiated SMX by the Fourier transform infrared (FT-IR) technique, confirming that SMX is a radioresistive material. Although SMX could not be accepted to be a good dosimetric material, the identification of irradiated SMX from the unirradiated sample was possible even for the low absorbed radiation doses and for a relatively long time (three months) after the irradiation process. Decay activation energy of the radical species, which is mostly responsible for the central intense resonance line, is calculated to be 45.15?kJ/mol by using the signal intensity decay data derived from annealing studies. Four radical species with different spectroscopic properties were accepted to be responsible for the ESR spectra of gamma-irradiated SMX, by simulation calculations. It is concluded that SMX and SMX-containing drugs can be sterilized by gamma radiation and ESR spectroscopy is an appropriate technique for the characterization of these induced radical intermediates during the gamma irradiation process of SMX. Toxicology tests should also be done for its safe usage.