Quantification of phenolic contents and antioxidant capacity of Atlantic sea cucumber, Cucumaria frondosa

The antioxidant activity (oxygen radical absorbance capacity, ORAC) and total phenols and flavonoids were determined in extracts from digestive tract, gonads, muscles and respiratory apparatus of sea cucumber, Cucumaria frondosa. Total phenols content varied from 22.5 to 236.0 mg of gallic acid equivalents/100 g dw, and flavonoids from 2.9 to 59.8 mg of rutin equivalents/100 g. ORAC values ranged from 140 to 800 μmol of Trolox equivalents/g dw. Among all extracts, best antioxidant potencies were observed in ethyl acetate extracts from digestive tract, and in acetonitrile-rich fractions obtained from mixed extracts using acetonitrile/TFA (trifluoroacetic acid) acidified water on muscles, gonads and respiratory apparatus. The weakest potencies were observed with water extracts from digestive tract and respiratory apparatus, and with water-rich fractions obtained from mixed extraction of gonads and muscles. A significant correlation was observed between ORAC values and total phenol content in extracts and fractions of gonads and muscles, but ORAC and phenols were not correlated in digestive tract and respiratory apparatus extracts. ORAC values were significantly correlated (p < 0.05) with total flavonoids in all extracts. Successive eluates obtained from solid-phase extraction of water-rich fractions using C₁₈ cartridge showed ORAC values (105–500 μmol of TE/g) reaching up to 2.3 times the potency of their parent fractions. Flavonoids are suggested to be mainly responsible for observed activities. Our results provide a first quantitative evaluation of C. frondosa tissues as useful sources of antioxidants for human consumption.     

A switched chaotic encryption scheme using multi-mode generalized modified transition map

Multimedia Tools and Applications - This paper presents a multi-mode generalized modified transition chaotic map and a switched chaotic encryption scheme based on it. Eight different modes of...     

Preparation,characterization and evaluation of polybenzoxazine thermoset/clay nanocomposites for metal coating

A series of polybenzoxazine-clay nanocomposites with various organoclay contents (3, 5, 10, and 20 wt%) were prepared by the one-shot procedure. from organo-montmorillonite (OMMT) and bifunctional benzoxazine, namely, bis-(3-dodecyel-3,4-dihydro-2H-1,3-benzoxazine) isopropane (B-dod). OMMTs were prepared by modification of Na-MMT with different ammonium salts of amines such as tyramine (Tyr), amino lauric acid (ALA) and N,N-dimethyl stearyl amine (DMS). Transmission electron microscope (TEM), X-ray diffraction (XRD) and infrared measurements (FTIR) were used to examine the structure and modification of OMMTs. The morphology of polybenzoxazine nanocomposites (B-dod/Tyr-MMT, B-dod/ALA-MMT, B-dod/DMS-MMT) was investigated by X-ray and TEM analyses. The X-ray analysis and TEM photos indicated that organoclay was exfoliated into polybenzoxazine matrix even at the highest organoclay loading (20%). Mechanical properties (viz, adhesion on metallic substrate, scratch hardness, tensile modulus, and elongation at break) of the prepared nanocomposites were measured. The tensile properties of prepared samples were examined; as the content of modified clay was increased, the tensile modulus increased; however, the elongation at break decreased. In addition, the optimum adhesion and scratch hardness values of the prepared nanocomposites were increased more than the neat resin, also, thermogravimetric analysis has the same manner. Therefore, the prepared nanocomposite materials could be successfully used for metal coatings.     

FPGA realization of a speech encryption system based on a generalized modified chaotic transition map and bit permutation

Multimedia Tools and Applications - This paper proposes a generalized modified chaotic transition map with three independent parameters. A hardware speech encryption scheme utilizing this map along...     

Monopyroxenic Basalt-Based Glass-Ceramics

Uniform, ultrafine, microcrystalline, hard, pyroxenic glass-ceramic materials have been obtained successfully from basalt rock; instead of adding nucleation catalysts, the FeO:Fe₂O₃, CaO:Na₂O, and CaO:MgO ratios have been rectified. This process has been accomplished by deliberately adding the smallest permissible amounts of oxidizers, limestone, dolomite, and soda ash (as additives) that are necessary to fulfill the monominerality requirements; these requirements affect the melting, workability, crystallization, and microstructure of the glass-ceramics. The melting temperature decreases as the ratios decrease (beyond certain limits); in addition, the workability, crystallization, and microstructure also improve as the ratios decrease. An almost-stable solid solution of augite or aegirine-augite composition is the only crystalline phase that is formed. The minimal FeO:Fe₂O₃ ratio and the likelihood of a greater affinity of the Na⁺ cation for the Fe³⁺ cation, rather than the Al³⁺ cation, may be responsible for increasing the stability and widening of the crystallization field of the complex aluminum-bearing pyroxene solid solution.     

Systematic organophilization of montmorillonite: The impact thereof on the rheometric and mechanical characteristics of NBR and SBR based nanocomposites

Different montmorillonites either, completely hydrophilic (Mont‐0), amphiphilic (Mont‐25, Mont‐50, and Mont‐75) or completely hydrophobic (Mont‐100) were used as reinforcing fillers for styrene butadiene rubber (SBR) and acrylonitrile butadiene rubber (NBR) individually to predict the influence of the different forms on the properties of the rubbers (rheometric characteristics and mechanical properties). The shifts in the glass transition temperatures after the clay insertion were determined from dynamic mechanical thermal analysis to investigate the preference and action of each form. In addition, the storage moduli were used as indications to the corresponding mechanical properties of the samples. The influences could be followed after comparing the impacts of aging conditions on the properties of rubber compositions. The obtained data may provide a platform to suggest the mechanism by which these forms can in some cases act as compatibilizers in addition to their reinforcing/plasticizing effect when employed with the physically incompatible NBR/SBR (50/50) blend, which helps to optimize the properties of nanocomposites based on these blends. The proposed mechanism of action showed good correlation with the results of the mechanical properties and x‐ray diffraction investigations as well. POLYM. ENG. SCI., 54:942–948, 2014. © 2013 Society of Plastics Engineers     

Fast relief from migraine attacks using fast-disintegrating sublingual zolmitriptan tablets

Zolmitriptan is a potent molecule for treatment of migraine. Its current oral therapies present drawbacks such as slow onset of action, low bioavailability and large inter-subject variability. Fast disintegrating sublingual zolmitriptan tablet (FDST) using freeze-drying technique has been developed to enhance tablet disintegration and dissolution with the intention of speeding drug absorption and onset of effect, hence mitigating the effects on the gastrointestinal dysmotility that typically accompanies the migraine attack. The FDSTs were prepared using different concentrations of gelatin as binder and mannitol or L-alanine as matrix supporting/disintegration enhancing agents. The effect of formulation variables on the physicochemical and solid-state properties, as well as the dissolution behaviour of the tablets, was studied. The formulated FDSTs disintegrated within 30 s and showed significantly faster dissolution rate of zolmitriptan compared to the zolmitriptan oral tablet. Tablet containing 2% gelatin and mannitol showed acceptable weight variation, drug content and friability values. Furthermore, it had a low in-vitro and in-vivo disintegration time (11 s) and it reached 100% of drug release within 30 s. This sublingual formulation gave faster and higher zolmitriptan plasma concentration in rabbits compared to the oral zolmetriptan market product. Zolmitriptan FDST may therefore constitute an advance in the management of acute migraine attacks.     

Catalytic para-xylene maximization. Part X: Toluene disproportionation on HF promoted H-ZSM-5 catalysts

H-ZSM-5 zeolite catalysts were doped with 2%, 3% and 4%HF to be used for investigating their activities and selectivities for xylenes production and for para-xylene maximization at temperatures of 300–500 °C via toluene disproportionation. This doping caused pore size modification of the H-ZSM-5 catalyst. The reaction was carried out in a fixed bed flow type reactor. The ratio of produced para-xylene relative to its thermodynamic composition reached as high as 3.29 at 300 °C on the 4%HF doped H-ZSM-5 catalyst although this catalyst possessed the lowest amount of the largest pores (3.0–5.7 nm) and the smallest pores (0.4–1.7 nm). The overall activities of the catalysts were decreased with an increase in HF doping because of diffusion restriction. The kinetics of the reaction were simply treated and found to give E_a and ΔS¹ values compatible with the characterization data of the catalysts.