Hypolipemic activity of polyphenol-rich extracts from Ocimum basilicum in Triton WR-1339-induced hyperlipidemic mice

The hypocholesterolemic and hypotriglyceridemic activities of the aqueous and organic extracts of Ocimum basilicum were studied using Triton WR-1339-induced hyperlipemic mice as an experimental model. Hyperlipidemia was developed by intraperitoneal injection of Triton (200 mg/kg body weight “BW”). The animals were divided into eight groups of eight mice each: normolipidemic control group (NCG), hyperlipidemic control group (HCG), hyperlipidemic plus DMSO control (HDCG), crude aqueous basil extract-treated group (CETG), dichloromethane extract-treated group (DETG), ethyl acetate extract-treated group (EETG), methanol extract-treated group (METG), and aqueous fraction-treated group (AFTG). After 7 h and 24 h of treatment, the intragastric administration of all extracts caused a significant decrease of plasma total cholesterol. Triglyceride levels were also significantly lowered but not in DETG. Similar results were observed for LDL-cholesterol concentrations. Although no significant change of HDL-cholesterol was noticed after 7 h of treatments, a significant increase of this cholesterol fraction was observed in EETG and AFTG after 24 h. Furthermore, crude aqueous basil extract and all polar solvent (methanol, ethyl acetate, water)-soluble fractions showed a significant ameliorative action on elevated atherogenic index (AI) and LDL/HDL-C ratios, while these atherogenic markers were not statistically suppressed by the dichloromethane-soluble extract. This finding indicates that O. basilicum may contain polar products able to lower plasma lipid concentrations and might be beneficial in treatment of hyperlipidemia and atherosclerosis.     

Antimicrobial activity and cellular toxicity of nanoparticle-polymyxin B conjugates

We investigate the antimicrobial activity and cytotoxicity to mammalian cells of conjugates of the peptide antibiotic polymyxin B (PMB) to Au nanoparticles and CdTe quantum dots. Au nanoparticles fully covered with PMB are identical in antimicrobial activity to the free drug alone, whereas partially-conjugated Au particles show decreased effectiveness in proportion to the concentration of Au. CdTe-PMB conjugates are more toxic to Escherichia coli than PMB alone, resulting in a flattening of the steep PMB dose-response curve. The effect is most pronounced at low concentrations of PMB, with a greater effect on the concentration required to reduce growth by half (IC50) than on the concentration needed to inhibit all growth (minimum inhibitory concentration, MIC). The Gram positive organism Staphylococcus aureus is resistant to both PMB and CdTe, showing minimal increased sensitivity when the two are conjugated. Measurement of reactive oxygen species (ROS) generation shows a significant reduction in photo-generated hydroxyl and superoxide radicals with CdTe-PMB as compared with bare CdTe. There is a corresponding reduction in toxicity of QD-PMB versus bare CdTe to mammalian cells, with nearly 100% survival in fibroblasts exposed to bactericidal concentrations of QD-PMB. The situation in bacteria is more complex: photoexcitation of the CdTe particles plays a small role in IC50 but has a significant effect on the MIC, suggesting that at least two different mechanisms are responsible for the antimicrobial action seen. These results show that it is possible to create antimicrobial agents using concentrations of CdTe quantum dots that do not harm mammalian cells.     

H2-induced copper and silver nanoparticle precipitation inside sol-gel silica optical fiber preforms

ABSTRACT: Ionic copper- or silver-doped dense silica rods have been prepared by sintering sol-gel porous silica xerogels doped with ionic precursors. The precipitation of Cu or Ag nanoparticles was achieved by heat treatment under hydrogen followed by annealing under air atmosphere. The surface plasmon resonance bands of copper and silver nanoparticles have been clearly observed in the absorption spectra. The spectral positions of these bands were found to depend slightly on the particle size, which could be tuned by varying the annealing conditions. Hence, transmission electron microscopy showed the formation of spherical copper nanoparticles with diameters in the range of 3.3 to 5.6 nm. On the other hand, in the case of silver, both spherical nanoparticles with diameters in the range of 3 to 6 nm and nano-rods were obtained.     

Thermal properties of proton-conducting radiation-grafted membranes

Proton-exchange membranes are required to exhibit chemical, mechanical, and thermal stability for fuel cell applications. The present investigation has been carried out to explore the thermal behavior of poly(ethylene-alt-tetrafluoroethylene) (ETFE)-based proton-conducting membranes, both uncrosslinked and crosslinked, prepared by radiation grafting and subsequent sulfonation. The influence of preparation steps (irradiation, grafting, sulfonation, crosslinking) on the thermal degradation, crystallinity, and melting behavior of membranes with varying degree of grafting was examined. ETFE base film and grafted films were studied as the reference materials. Furthermore, poly(tetrafluoroethylene-co-hexafluoropropylene)-based grafted films and membranes were investigated as well for comparison. Membrane preparation steps, degree of grafting, crosslinking, type of base polymer have considerable influence on the thermal properties of membranes. The crystallinity of the films decreases slightly by grafting, while a significant decrease was observed after sulfonation. For instance, crystallinity decreased from 37% (pristine ETFE) to 36% (uncrosslinked grafted film) and 23% (uncrosslinked ETFE-based membrane). On the other hand, the melting temperature of the base polymer was almost unaffected by irradiation and grafting. The crosslinked ETFE-based membranes exhibit a slightly higher melting temperature (262.5°C) than their corresponding grafted films (261.3°C) and the base film (260.6°C). © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Assay of tyrosol and hydroxytyrosol in olive oil by tandem mass spectrometry and isotope dilution method

Hydroxytyrosol and tyrosol, the strong antioxidant present in large amount in virgin olive oil have been assayed by LC-MS/MS under MRM condition and isotope dilution method, using d(2)-labelled internal standards obtained by simple synthetic procedures. The assay has been performed under MRM condition monitoring two transitions for each analyte to improve the specificity. This paper deals with a modern approach for assaying the content of this polyphenols in virgin olive oil down to a limit of a few hundreds of parts per billion. Tyrosol and hydroxytyrosol ranged from 10 to 47ppm and from 5 to 25ppm in commercial olive oil, respectively. The accuracy (98-107%) and analytical parameters values confirm the reliability of the proposed approach. The method can be extended to any natural matrices, including mill wastes, after a simple step of sample preparation.     

Recursive system identification method from binary input/output measurements

This paper presents two online identification algorithms of finite impulse response (FIR) systems using binary measurements both on the input and on the output. These algorithms are based on the least mean square (LMS) technique and on the estimation of the correlation functions of the input and output from binary data. Note that the second algorithm is a simplified version of the first one in the case of a white noise on the input. The convergence and variance analyses are provided. A numerical example is given to demonstrate the effectiveness of the proposed algorithms.     

Adaptive integral-type terminal sliding mode control: Application to trajectory tracking for mobile robot

This paper presents an Adaptive Terminal Integral Sliding Mode Control (ATISMC) scheme for trajectory tracking problems applied to a differential Wheeled Mobile Robot (WMR). First, a terminal integral sliding variable is designed. Based on the finite-time concept, an adaptive control law has been developed in which a switching gain is adjusted adaptively by using a novel strategy. This control method aims to deal with unknown bounded disturbances and uncertainties. Moreover, it allows fast convergence of the system states to an equilibrium point. The main features of the proposed ATISMC are its robustness, fast convergence rate, and chattering avoidance. To realize trajectory tracking for WMR, the ATISMC is incorporated into a double closed loop scheme. Stability analysis is performed using the Lyapunov stability theory. Numerical simulations and real-time experiments demonstrate the feasibility of the proposed controller scheme. A comparison study with the classical ISMC was performed to show the superiority of the developed method.     

Coupling spring-induced resonance shift in PDNB system with PSH network

Microsystem Technologies - The dynamic vibration analysis of a perforated double-nanobeam (PDNB) system with a periodic square holes (PSH) network is researched in this paper. Both nanobeams are...     

An Efficient Hybrid Model for Arabic Text Recognition

In recent years, Deep Learning models have become indispensable in several fields such as computer vision, automatic object recognition, and automatic natural language processing. The implementation of a robust and efficient handwritten text recognition system remains a challenge for the research community in this field, especially for the Arabic language, which, compared to other languages, has a dearth of published works. In this work, we presented an efficient and new system for offline Arabic handwritten text recognition. Our new approach is based on the combination of a Convolutional Neural Network (CNN) and a Bidirectional Long-Term Memory (BLSTM) followed by a Connectionist Temporal Classification layer (CTC). Moreover, during the training phase of the model, we introduce an algorithm of data augmentation to increase the quality of data. Our proposed approach can recognize Arabic handwritten texts without the need to segment the characters, thus overcoming several problems related to this point. To train and test (evaluate) our approach, we used two Arabic handwritten text recognition databases, which are IFN/ENIT and KHATT. The Experimental results show that our new approach, compared to other methods in the literature, gives better results.