Magnetic nanocellulose hybrid nanoparticles and ionic liquid for extraction of neonicotinoid insecticides from milk samples prior to determination by liquid chromatography-mass spectrometry

A simple and rapid microextraction procedure is reported on the use of ionic liquid in combination with magnetic nanocellulose hybrid nanoparticles. The procedure is ultrasound-assisted and applicable to selective preconcentration of neonicotinoid insecticides from milk samples, prior to being analysed by liquid chromatography-mass spectrometry. The extraction procedure uses small volume of organic solvents (<1 mL), and there is no need for centrifugation. In the experimental approach the ionic liquid was quickly disrupted by an ultrasonic probe and dispersed in milk samples in a cloudy form. At this stage, neonicotinoid insecticides were extracted into the fine droplets of ionic liquid. Then small amounts of magnetic nanocellulose hybrid nanoparticles were dispersed into the sample solutions to adsorb the ionic liquid containing the analytes and phase separation was completed. The ionic liquid allowed the microextraction of the analytes and a small volume of acetonitrile was used for elution. Magnetic nanocellulose favoured the adsorption of the ionic liquid with the analytes and improved the final recovery with respect to the use of simple magnetic nanoparticles as a sorbent material. Under the optimum conditions, decision capabilities were achieved in the 0.02–0.06 mg kg^?1 range, with recoveries between 91.0% and 109.5%.     

Detection of malicious users in cognitive radio ad hoc networks: A non-parametric statistical approach

Cognitive radio ad hoc networks (CRAHN) operation is based on the reliability of the spectrum sensing. It has been proved that cooperation between secondary users improves the accuracy of the sensing information gathered by the users. However, such cooperation also increases the vulnerability of the network and its exposure to attacks. The paper presents a novel algorithm based on the non-parametric Kruskal–Wallis and Conover–Inman tests to detect and identify the attack of malicious users at the MAC layer. The algorithm, denoted by KWD, does not assume a priori knowledge neither of the activity of the primary channel nor of the existence and the behavior of malicious users.     

In pregnancies with gestational diabetes mellitus and intensive therapy, perinatal outcome is worse in small-for-gestational-age newborns

Solution phase combinatorial synthesis of flavone derivatives and evaluation of their affinity for the central benzodiazepine receptors is described. The libraries preparation is simple and provides a convenient method for rapid compound generation and screening. Thirty one new compounds were obtained of which the most promising, as high affinity benzodiazepine receptor ligands, were 6-bromo-3'-fluoroflavone; 6,3'-dichloroflavone; 6-bromo-3'-chloroflavone and 6-chloro-3'-bromoflavone.     

Electroantennogram activity from antennae ofCeratitis capitata (Wied.) to fresh orange airborne volatiles

Twenty-six compounds have been identified from fresh orange airborne volatiles, the most abundant being limonene and alloaromadendrene. Ethyl- and butylhexanoates were found in middle concentrations, whereas the other compounds occur at low levels. Electroantennograms recorded fromCeratitis capitata Wied. (males and females) revealed limonene. butyl hexanoate, dihydrocarvone, and limonene oxide to be most active. In the case of dihydrocarvone, 4-ethyl acetophenone, and carvone, female antennae give greater responses than antennae of males. Limonene oxide was more active for males than females. Total airborne volatiles recovered from oranges elicited high EAGs, with females being more sensitive than males.     

On WCDMA base station selection criteria

This letter presents a BS selection criterion for WCDMA that allows selecting the base station requiring the minimum transmission power in both the uplink and downlink direction. The importance of minimizing transmitted power lies on the associated interference reduction and, consequently, the capacity increase. Furthermore, it is shown that, with a proper setting of the parameters, the criterion used in practical WCDMA systems based on Ec/Io measurements can be adjusted to provide results similar to the proposed method.