Determination of azinphos-methyl and parathion-methyl in honey by stripping voltammetry

An electrochemical method for the determination of azinphos-methyl and parathion-methyl in honey is presented. The determination is established by adsorptive stripping differential pulse voltammetry at hanging mercury working electrode.In contrast to the chromatographic methods for the determination of pesticide residues, the sample preparation of the proposed method is minimal; analytes were extracted from honey samples with a mixture of (acetone):(Britton-Robinson buffer) and then were analyzed without any additional pretreatment.The response of the analytes either individually or as a mixture was studied for a series of deposition time and molar ratio. Two quantitation protocols were compared, using either the external calibration or the standard addition method. Accuracy was tested with spiked honey samples obtaining good recovery values. The limit of detection for the honey sample (for deposition time of 10 s) was calculated 51.71 μg kg⁻¹ for MeP and 65.87 μg kg⁻¹ for AzMet.     

Handling zero in diminished-one modulo 2 n + 1 adders

Zero treatment in diminished-one modulo 2 ⁿ + 1 addition has traditionally been performed separately, leading to slow and area-consuming implementations. To overcome this, on the basis of an enhanced number representation used previously, we introduce novel carry look ahead and parallel-prefix architectures for diminished-one modulo 2 ⁿ + 1 adders that can also handle operands equal to 0. Translators for the new representation are also given.     

Observations of Twelve USEPA Priority Polycyclic Aromatic Hydrocarbons in the Aitken Size Range (10–32 nm D p )

Particle size distribution measurements of twelve USEPA priority pollutant polycyclic aromatic hydrocarbons (PAHs)—collected in Riverside, California, down to 10 nm aerodynamic diameter (D_p)—observed on integrated nocturnal samples (7:00 p.m.-6:30 a.m.) revealed that between 46 and 100% of the mass of particles in the Aitken size range was found in the 10–18 nm size bin. Particles in this size range have high alveolar deposition efficiency.     

Forward, backward, and symmetric solutions of discrete ARMA representations

The main objective of this paper is to determine a closed formula for the forward, backward, and symmetric solution of a general discrete-time Autoregressive Moving Average representation. The importance of this formula is that it is easily implemented in a computer algorithm and gives rise to the solution of analysis, synthesis, and design problems.     

Studies on the chemical, physical and mechanical properties of high-solids clearcoats prepared from hydroxyl-terminated isophthalate-based oligoesters and a melamine resin

A series of high-solids (solvent-free) clearcoats was prepared from hydroxyl-terminated isophthalate-based oligoesters and the hexakis(methoxymethylol)melamine resin (HMMM). The oligoesters, which were used as binders, were prepared via a transesterification reaction of dimethyl isophthalate (DI) under various molar ratios R (=mol ratio diols/diester) with a mixture of 1,6-hexanediol (HD) and 2-methyl-1,3-propanediol (MP). Mixtures of the two diols of different composition R_d (=mol ratio HD/MP), were used as well. An attempt was made to investigate and correlate the chemical, physical and mechanical properties of the formulated solvent-free clearcoats to: (a) the amount of the cross-linker (melamine resin); (b) the curing conditions (time and temperature); (c) the synthetic parameters applied in the preparation (via transesterification) of the oligoesters (e.g. excess of the diols in reaction with the DI and the molar ratio between the two diols, the species of the Lewis acid catalyst). The properties of all the new formulated high-solids clearcoats were compared to those of a reference clearcoat and their cross-linking was correlated to their chemical structure and composition as well as to their T_g values. It was found that the R and R_d values applied in the synthesis of the oligoesters (binders) significantly affected the performance of their corresponding clearcoats. More specifically, the clearcoats obtained from binders where 3<R<4, combined an enhanced processability, higher values of non-volatiles (80%) (lower VOC content) and better or comparable chemical, physical and mechanical properties (e.g. impact resistance, gasoline resistance, mar resistance, flexibility and pencil hardness) upon comparison to those of the reference clearcoat.     

Radical-scavenging activity of Aegean Sea marine algae

In the present work, thirteen algae from the Aegean Sea were examined for radical-scavenging activity (RSA) using the DPPH and chemiluminescence (CL) tests. Extracts of the brown alga Taonia atomaria exhibited the best RSA in comparison to the extracts of the other investigated species and approached the activity of powerful antioxidant standards. Column chromatography separation of T. atomaria extract, followed by preparative HPLC, resulted in the isolation of six metabolites, which were identified by spectral analyses (¹H NMR, ¹³C NMR and MS). The isolated metabolites taondiol, isoepitaondiol, stypodiol, stypoldione, sargaquinone and sargaol were found to possess marked RSA.     

Waveform classification and information extraction from LIDAR databy neural networks

Two different neural network schemes for the classification of light detection and ranging (LIDAR) waveforms for the LARSEN 500 airborne system and for extraction of ocean information are proposed. The first method employs a single layer of linear neurons for classification of waveforms into various clusters. Both unsupervised and supervised learning algorithms have been employed to demonstrate the spatial distribution of milt in near-shore waters. In the second method, a new multistage multilayer feedforward architecture is used for the classification of the waveforms and for the extraction of various types of ocean information. The stage I networks work in a parallel fashion and map the input waveforms to a set of characteristics. The networks in stage II use these characteristics to assign a signature number to the waveform or extract other information. Both the schemes are used with real-world data collected by the LARSEN 500 system. The paper concludes with experimental results and comparisons     

Data collection and analysis of the building stock and its energy performance—An example for Hellenic buildings

The process of building labeling and certification in accordance to the provisions of the European Directive on the Energy Performance of Buildings (EPBD) constitutes a unique opportunity for collecting information on the characteristics of the building stock and its energy performance on a national and European level. Thus, there is a need to handle data from a large stock of buildings and to be able to analyse information and extract practical trends and benchmarks. Stakeholders and technical managers who oversee a number of buildings experience similar needs in order to collect, organize and monitor the energy performance of a large pool of buildings. To facilitate these efforts, a common evaluation database and complimentary software for its exploitation have been developed in the frame of a European project.This paper presents an overview of the database and its available tools, and the main results from a case study on Hellenic buildings that reveals relevant characteristics. The Hellenic database included a sample of 250 buildings from different regions in Greece, with a breakdown that is representative of the national building stock. The main results focus on the buildings’ energy performance, thermal envelope characteristics and the exploitation of solar thermal energy.     

Ultrafine particles from diesel vehicle emissions at different driving cycles induce differential vascular pro-inflammatory responses: Implication of chemical components and NF-κB signaling

Background

Nanometer silicon dioxide (nano-SiO₂) has a wide variety of applications in material sciences, engineering and medicine; however, the potential cell biological and proteomic effects of nano-SiO₂ exposure and the toxic mechanisms remain far from clear.

Results

Here, we evaluated the effects of amorphous nano-SiO₂ (15-nm, 30-nm SiO₂). on cellular viability, cell cycle, apoptosis and protein expression in HaCaT cells by using biochemical and morphological analysis, two-dimensional differential gel electrophoresis (2D-DIGE) as well as mass spectrometry (MS). We found that the cellular viability of HaCaT cells was significantly decreased in a dose-dependent manner after the treatment of nano-SiO₂ and micro-sized SiO₂ particles. The IC₅₀ value (50% concentration of inhibition) was associated with the size of SiO₂ particles. Exposure to nano-SiO₂ and micro-sized SiO₂ particles also induced apoptosis in HaCaT cells in a dose-dependent manner. Furthermore, the smaller SiO₂ particle size was, the higher apoptotic rate the cells underwent. The proteomic analysis revealed that 16 differentially expressed proteins were induced by SiO₂ exposure, and that the expression levels of the differentially expressed proteins were associated with the particle size. The 16 proteins were identified by MALDI-TOF-TOF-MS analysis and could be classified into 5 categories according to their functions. They include oxidative stress-associated proteins; cytoskeleton-associated proteins; molecular chaperones; energy metabolism-associated proteins; apoptosis and tumor-associated proteins.

Conclusions

These results showed that nano-SiO₂ exposure exerted toxic effects and altered protein expression in HaCaT cells. The data indicated the alterations of the proteins, such as the proteins associated with oxidative stress and apoptosis, could be involved in the toxic mechanisms of nano-SiO₂ exposure.     

Induced lactic acid fermentation of untreated green olives of the Conservolea cultivar by Lactobacillus pentosus

Inoculation of untreated green olives of the Conservolea cultivar (Olea europea media rotunda) with a commercial strain of Lactobacillus pentosus with/without glucose supplement was studied. Despite an initial loss in viability of 0.5 log cycles on average, due to lack of adaptation of the starter to the saline environment of the brine, cultures grew well and initiated an accelerated fermentation process. Inoculation reduced the survival period of Enterobacteriaceae, and consequently potential spoilage, and caused a quicker acidification of brines and decrease in pH compared with control uninoculated processes. The diffusion of phenolic compounds was slow, hindered by the epidermis of the fruits, and had no effect on the growth of the starter. HPLC analysis revealed that lactic and acetic acids were among the end‐products during the fermentation of green olives. Citric, tartaric and malic acids were also detected but at much lower concentrations. Results obtained from this work can be applied directly to industry for the effective use of starter cultures on natural fermentation processes of green olives without prior lye treatment. © 2003 Society of Chemical Industry