An-Najah Staff

Around 90 samples of Roman wall painting dating from the first to the third century AD were analysed using different analytical techniques: X-ray diffraction, X-ray fluorescence, infrared spectrometry, scanning electron microscopy, energy dispersive spectrometry, optical microscopy and physico-chemical tests. The identified pigments are: ash, calcite, carbon black, celadonite, cinnabar, Egyptian Blue, glauconite, goethite, hematite and red lead. Pigment mixtures were used to get other colours such as brown, pink or purple. Three types of plaster were used: a first, and most dominant, with river sand, a second with crushed tile for damp places and a third, to which cinnabar was exclusively applied, was prepared with crushed calcite crystals.

Extract of various plants (Wrightiatinctoria, Clerodendrumphlomidis, Ipomoeatriloba) leaves was investigated as corrosion inhibitor of mild steel in 0.5M H2SO4 using conventional weight loss, electrochemical polarization, electrochemical impedance spectroscopy and scanning electron microscopic studies. The weight loss results showed that all the plant extracts are excellent corrosion inhibitors, electrochemical polarization data revealed the mixed mode of inhibition and the results of electrochemical impedance spectroscopy have shown that the change in the impedance parameters, charge transfer resistance and double layer capacitance, with the change in concentration of the extract is due to the adsorption of active molecules leading to the formation of a protective layer on the surface of mild steel. Scanning electron microscopic studies provided the confirmatory evidence of improved surface condition, due to the adsorption, for the corrosion protection.

Switchgrass (Panicum virgatum L.) is a warm-season perennial grass that has received considerable attention as a potential dedicated biofuel and bioproduct feedstock. Genetic improvement of switchgrass is needed for better cellulosic ethanol production, especially to improve cellulose-to-lignin ratios. Cell suspension cultures offer an in vitro system for mutant selection, mass propagation, gene transfer, and cell biology. Toward this end, switchgrass cell suspension cultures were initiated from embryogenic callus obtained from genotype Alamo 2. They have been established and characterized with different cell type morphologies: sandy, fine milky, and ultrafine cultures. Characterization includes histological analysis using scanning electron microscopy, and utility using protoplast isolation. A high protoplast isolation rate of up to 106 protoplasts/1.0 g of cells was achieved for the fine milky culture, whereas only a few protoplasts were isolated for the sandy and ultrafine cultures. These results indicate that switchgrass cell suspension type sizably impacts the efficiency of protoplast isolation, suggesting its significance in other applications. The establishment of different switchgrass suspension culture cell types provides the opportunity to gain insights into the versatility of the system that would further augment switchgrass biology research.