To evaluate the efficacy of an ethanolic Salvadora persica extract in removing the smear layer following a root canal procedure. Methods: Sixty extracted, single-rooted human teeth were cleaned, shaped, and divided into four groups. Experimental groups 1 (n= 20) and 2 (n=20) were irrigated with 1 mg/ml and 5 mg/ml of S. persica, respectively. The positive controls (n= 10) were irrigated with 17% ethylenediaminetetraacetic acid (EDTA), while the negative controls (n= 10) were irrigated with saline.

Currently the construction of a solar tower pilot plant for high temperature solar gas turbine in the Riyadh Techno Valley on the campus of King Saud University is under way. The purpose of the pilot plant is to demonstrate the feasibility of innovative solid particle receiver and thermal energy storage concepts that can achieve temperatures up to 1000°C, using sand as the heat transfer and energy storage medium. The heliostat field of the pilot plant is designed to concentrate 300 kWth direct solar radiation onto the ca.