Potential tsunami risk assessment to the city of Alexandria, Egypt.

Tsunami extreme events present a highly significant hazard and considerable risk to the coastal communities. The continued occurrence of tsunami incidents, together with population growth, increases the risk in coastal communities. Two known catastrophic historic tsunamis in Alexandria occurred in the years 365 and 1303 AD, with reported wave heights of 1 m and 2.9 m, respectively. Approximately 5000 people lost their lives and 50,000 homes were destroyed in the city after the earthquake in 365. The 1303 tsunami destroyed the great lighthouse of Alexandria, one of the seven wonders of the ancient world. In order to avoid such events in the future, a detailed knowledge about the tsunami phenomenon and its potential risk is needed. In this paper, the vulnerability and risk to the city of Alexandria will be examined by remote sensing and GIS techniques considering three scenarios. Methodology used depends on building a comprehensive GIS in addition to recent satellite images. After digitizing raster data, it was then stored into a vector format. A digital parcel map was created; attributes (like distance to shore line, elevation, land use/cover, and population) for each polygon were added. Using the Shuttle Radar Topography Mission images, a digital elevation model was created, to test all the tsunami scenarios (based on 5 m, 9 m, and 20 m wave's height). Finally, vulnerability analysis including physical as well as social and economic constraints was executed for the determination of the vulnerability level of elements. Results indicated that Alexandria city is highly vulnerable to tsunami hazard. Very high risk covers the biggest portion of the area in Alexandria (49.16% and 58.71%), followed by high risk (30% and 28.41%), medium risk (13.61% and 7.76%), and low and very low risk (20.82% and 12.88%).

Polyphenols in Ammania auriculata: structures, antioxidative activity and cytotoxicity.

Chemical and biological investigations of the extract of Ammania auriculata (Lytheraceae) resulted in the identification of eight polyphenols (1 - 8) for the first time from this plant, including the gallotannin, 2,3,6-tri-O-galloyl-(α,ß)-4C1-glucopyranose (8), for which 1D and 2D-NMR spectra were recorded and assigned for the first time. The structures of all isolates (1 - 8) were elucidated by conventional methods, spectroscopic analysis, including 1D and 2D NMR, and by HR-ESIMS as well. All of the isolated compounds were evaluated for their antioxidant activities, determined by the DPPH and ORAC methods and for their cytotoxicity against the keratinocyte cell line HaCaT using the neutral red assay (NRU) and cell cycle analysis. Compounds 1, 3, 4, 5, and 6 significantly inhibited reactive oxygen species production with ED50 values between 3.22 and 9.79 µg/ml. Compounds 1, 3, 4, and 5 showed cytotoxic activity against HaCaT cells with IC50 values between 30.7 and 84.1 µg/ml. The new galloyl glucose (8) was found not cytotoxic. Ellagitannins, 2,3-hexahydroxy-((α/ß)-glucopyranose (1) and 1 -0-galloyl 2,3-hexahydroxy-(α)-glucopyranose (5) possess remarkable antioxidative and comparably weak cytotoxic activity.

Three-phase double-arc plasma for spectrochemical analysis of environmental samples.

A new instrument, which uses a three-phase current to support a double-arc argon plasma torch for evaporation, atomization and excitation of solid or powder samples, is described. The sampling arc is ignited between the first and second electrode while the excitation arc is ignited between the second and third electrode. Aerosol generated from the sample (first electrode) is swept by argon gas, through a hole in the second electrode (carbon tubing electrode), into the excitation plasma. A tangential stream of argon gas is introduced through an inlet orifice as a coolant gas for the second electrode. This gas stream forces the excitation arc discharge to rotate reproducibly around the electrode surface. Discharge rotation increases the stability of the excitation plasma. Spectroscopic measurements are made directly in the current-carrying region of the excitation arc. An evaluation of each parameter influencing the device performance was performed. Analytical calibration curves were obtained for Fe, Al, K, and Pb. Finally, the present technique was applied for the analysis of environmental samples. The present method appears to have significant, low cost analytical utility for environmental measurements.