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- Author or Editor: S. Khaled x
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Abstract
The k 0-standardization method of NAA is known as one of the most remarkable progress of NAA with its many advantages. Recently, our laboratory is highly involved in various areas of application of k 0-NAA. This paper focuses on the application of the k 0-NAA method in Nutritional and Health-Related Environmental field. Tobacco holds a leading position among different commodities of human consumption. The adverse health effects of toxic and trace elements in tobacco smoke on smokers and non-smokers are a special concern. In the present study, the concentration of 24 trace elements in cigarette tobacco of five different brands of Algerian and American cigarettes have been determined by k 0-based INAA method. The results were compared with those obtained for samples from Iranian, Turkish, Brazilian and Mexican cigarettes tobacco. To evaluate the accurate of the results the SRM IAEA-140/TM was executed. The analytical results showed that the relative error of most of the elements was less than 10%.
Artificial pozzolanic cement pastes containing burnt clay with and without silica fume
Physicochemical, microstructural and thermal characteristics
Abstract
Pozzolanic cement blends were prepared by the partial substitution of ordinary Portland cement (OPC) with different percentages of burnt clay (BC), Libyan clay fired at 700 °C, of 10, 20, and 30%. The pastes were made using an initial water/solid ratio of 0.30 by mass of each cement blend and hydrated for 1, 3, 7, 28, and 90 days. The pozzolanic OPC–BC blend containing 30% BC was also admixed with 2.5 and 5% silica fume (SF) to improve the physicomechanical characteristics. The hardened pozzolanic cement pastes were subjected to compressive strength and hydration kinetics tests. The results of compressive strength indicated slightly higher values for the paste made of OPC–BC blend containing 10% BC The results of DSC and XRD studies indicated the formation and later the stabilization of calcium silicates hydrates (CSH) and calcium aluminosilicate hydrates (C3ASH4 and C2ASH8) as the main hydration products in addition to free calcium hydroxide (CH). Scanning electron microscopic (SEM) examination revealed that the pozzolanic cement pastes made of OPC–BC mixes possesses a denser structure than that of the neat OPC paste. Furthermore, the addition of SF resulted in a further densification of the microstructure of the hardened OPC–BC–SF pastes; this was reflected on the observed improvement in the compressive strength values at all ages of hydration.
Abstract
Traditional medicinal seeds prescribed for specific treatment purposes, were purchased from local markets and analyzed by INAA. The samples were irradiated at Es-Salam research reactor, at a power of 5 MW for 6 h. The accuracy of the method was established by analyzing reference materials. Twenty elements were measured, with good accuracy and reproducibility. The concentration of elements determined, was found to vary depending on the seeds. The daily intake of essential and toxic elements was determined, and compared with the recommended values. The probable cumulative intake of toxic elements is well below the tolerance limits.
Despite the current therapeutic options, filamentous fungal infections are associated with high mortality rate especially in immunocompromised patients. In order to find a new potential therapeutic approach, the in vitro inhibitory effect of two antiarrhythmic agents, diltiazem and verapamil hydrochloride were tested against different clinical isolates of ascomycetous and mucoralean filamentous fungi. The in vitro combinations of these non-antifungal drugs with azole and polyene antifungal agents were also examined. Susceptibility tests were carried out using the broth microdilution method according to the instructions of the Clinical and Laboratory Standards Institute document M38-A2. Checkerboard microdilution assay was used to assess the interactions between antifungal and non-antifungal drugs. Compared to antifungal agents, diltiazem and verapamil hydrochloride exerted a relatively low antifungal activity with high minimal inhibitory concentration values (853–2731 μg/ml). Although in combination they could increase the antifungal activity of amphotericin B, itraconazole and voriconazole. Indifferent and synergistic interactions were registered in 33 and 17 cases, respectively. Antagonistic interactions were not revealed between the investigated compounds. However, the observed high MICs suggest that these agents could not be considered as alternative systemic antifungal agents.
