Fusion of Synchronous Fluorescence Spectra with Application to Argan Oil for Adulteration Analysis

When synchronous fluorescence (SyF) spectroscopy is used for quantitative and qualitative analysis, selection of a useful wavelength interval between the excitation and emission wavelengths (Δλ) is needed. Presented is a fusion approach to combine Δλ intervals thereby negating the selection process. This study uses the fusion of SyF spectra to detect adulteration of argan oil by corn oil and quantitative analysis of the corn oil content. The SyF spectra were acquired by varying the excitation wavelength in the region 300-800 nm using Δλ wavelength intervals from 10 to 100 nm in steps of 10 nm producing 10 sets of SyF spectra. For quantitative analysis, two calibration approaches are evaluated with these 10 SyF spectral datasets. Multivariate calibration by partial least squares (PLS) and a univariate calibration process where the SyF spectra are summed over respective SyF spectral ranges, the area under the curve (AUC) method. For adulteration detection and quantitation of the corn oil, prediction errors decrease with fusion compared to individually using the 10 Δλ interval SyF spectral data sets. For this data set, the AUC method generally provides smaller prediction errors than PLS at individual Δλ intervals as well as with fusion of all 10 Δλ intervals

DFT Study of Electronic and Optical Properties of Small Oligothiophenes Based on Terthiophene End-capped by Several Donor Groups

Eight small molecules based on terthiophene end-capped by several donor groups have been carried out using density functional theory (DFT) and time-dependent (TDDFT) methods in neutral and doped states. The theoretical ground-state geometry, electronic structure and optical properties of the studied molecules were obtained by the DFT and TD-DFT methods at the B3LYP level with 6-31G(d) basis set. Theoretical knowledge of the highest occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital (LUMO) energy levels the gap energy (Eg) and the open-circuit voltage (Voc) of the studied compounds are calculated and discussed. The effects of the donor group substituents on the geometries and optoelectronic properties of these materials are discussed to investigate the relationship between molecular structure and optoelectronic properties. The results of this work suggest some of these materials as a good candidate for organic solar cells. DOI: http://dx.doi.org/10.17807/orbital.v9i3.99

An exact method for solving the two-machine flow-shop problem with time delays

International audienc

New π-Conjugated Materials Based on Furylenevinylene Candidate for Organic Solar Cells Application: A DFT Study

The specific properties of organic-conjugated molecules and polymers are of great importance since they have become the most promising materials for the optoelectronic device technology such as solar cells. The use of low band gap materials is a viable method for better harvesting of the solar spectrum and increasing its efficiency. The control of the parameters of these materials is a research issue of ongoing interest. In this work, a quantum chemical investigation was performed to explore the optical and electronic properties of a series of different compounds based on furylenevinylene. Different electron side groups were introduced to investigate their effects on the electronic structure. The theoretical knowledge of the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels of the components is basic in studying organic solar cells; so the HOMO, LUMO, Gap energy and open circuit voltage (Voc) of the studied compounds have been calculated and reported. These properties suggest that these materials behave as good candidate for organic solar cells. DOI: http://dx.doi.org/10.17807/orbital.v7i4.76

Poly(neutral red) based hydrogen peroxide biosensor for chromium determination by inhibition measurements

Amperometric hydrogen peroxide enzyme inhibition biosensors based on horseradish peroxidase (HRP) immobilised on electropolymerised neutral red (NR) or directly on the surface of carbon film electrodes (CFE) have been successfully applied to the determination of toxic Cr(III) and Cr(VI). Parameters influencing the performance of the biosensor including the enzyme immobilisation method, the amount of hydrogen peroxide, applied potential and electrolyte pH were optimised. The inhibition of horseradish peroxidase by the chromium species was studied under the optimised conditions. Results from the quantitative analysis of chromium ions are discussed in terms of detection limit, linear range and sensitivity. The HRP kinetic interactions reveal mixed binding of Cr(III) with I50 = 3.8 μM and inhibition binding constant Ki = 11.3 μM at HRP/PNR/CFE biosensors and uncompetitive binding of Cr(VI) with I50 = 3.9 μM and Ki = 0.78 μM at HRP/CFE biosensors in the presence of H2O2 substrate. Interferences from other heavy metal ions were studied and the inhibition show very good selectivity towards Cr(III) and Cr(VI)

Green Synthesis of Molecularly Imprinted Polymers for Dispersive Magnetic Solid-Phase Extraction of Erythrosine B Associated with Smartphone Detection in Food Samples

Monitoring synthetic colorants in foods is important due to their potential toxicity and pathogenicity. We propose here a new and simple method for the extraction and determination of erythrosine B (ERT-B) in food samples. A composite of polydopamine-based molecularly imprinted polymers coating magnetic nanoparticles (Fe3O4@PDA@MIP) was synthesized using a green approach and exploited for the magnetic dispersive solid-phase extraction (MDSPE) of ERT-B. Fe3O4@PDA@MIP provides a rapid extraction of ERT-B, exhibiting good reusability and preconcentration ability. Moreover, the MIP showed a relatively good imprinting factor (3.0 +/- 0.05), demonstrating excellent selectivity against patent blue (an interfering dye) and other food matrix components. The proposed MDSPE was coupled to colorimetric smartphone-based detection that allowed us to obtain similar performances of UV-Vis spectroscopy detection. The smartphone-based optical detection facilitated the determination of ERT-B in the 0.5-10 mg/L range, with a limit of detection of 0.04 mg/L. The developed method was successfully employed to determine ERT-B in food samples (juice, candy, and candied cherries) with good recovery values (82-97%)

Aflatoxines : Toxiques redoutables dans nos aliments

Les aflatoxines sont des métabolites produits par des moisissures du genre Aspergillus et plus particulièrement A. flavus et A. parsiticus se développant sur différents produits alimentaires. Ainsi, on les trouve dans les céréales, le maïs, le riz et aussi dans les graines de coton, les épices et le lait. Ces mycotoxines sont connues pour leur grande toxicité et leurs effets mutagéniques, tératogéniques et carcinogéniques. C’est ainsi que de nombreux pays ont instauré une législation stricte quand aux quantités maximales admissibles des aflatoxines dans les aliments. La protection contre d’éventuelles aflatoxicoses reste évidente. Seul le contrôle continu des aliments assure leur innocuité. Des techniques performantes et sensibles sont largement utilisées pour ces fins sécuritaires

Giant viable hydatid cyst of the lung revealed by hiccups

Hydatid cystic disease is still a significant clinical problem in endemic countries. Hydatid cysts are usually located in the liver and lung. The resulting large cysts in the lung are a special clinical entity called giant hydatid cysts. We present a case of this rare entity: An 18-year-old woman presented with three month history of hiccups and progressive dyspnea. Chest X-ray revealed a very large homogenous opacity of the left lung. A diagnosis of giant hydatid cyst was made intra operatively; the patient was treated surgically using cystotomy and capitonnage without post-operative complications. This report illustrates that the hydatid cyst of the lung may occasionally present with signs of mediastinal compression.Pan African Medical Journal 2012; 13:4

LE TAGINE MAROCAIN UN DÉLICE …MAIS DANGER POUR LA SANTÉ!!!

Les tajines marocains font une nouvelle fois parler d’eux, c’est une assiette de faïence émaillée, souvent de couleur rouille, munie d'un grand couvercle en forme de cône. Il s'agit d’un contenant dans lequel on fait cuire et servir des plats traditionnels marocains.En effet des études récentes par des équipes du Canada, d’Australie et d’Allemagne ont montré que les tajines marocains produisent un taux élevé de plomb, ce qui représente un risque potentiel pour la santé.C’est dans ce contexte, que nous nous sommes intéressés à appliquer une méthode électrochimique simple et pratique pour contrôler la présence du plomb dans les glaçures des tajines vendus sur le marché marocain.Les résultats préliminaires de ce travail ont confirmé que les concentrations du plomb lessivable dans les tajines sont supérieures à la concentration maximale permise 5,0 ppm, par le règlement sur les produits céramiques émaillés et produits de verre. Les concentrations de plomb lessivable par les tajines de légumes acides telles que les citrons et les tomates varient entre 37 ppm à 47ppm, très supérieures à celles trouvées dans les glaçures de tajine traitées par l’acide acétique. Ce qui représente un vrai danger direct pour les consommateurs