Essential oils of Retama raetam from Libya: chemical composition and antimicrobial activity

Retama raetam (Forssk) Webb & Berthel is well known in the folk medicine of North and East Mediterranean regions for the treatment of microbial infections. The powdered leaves are used to heal circumcision wounds and used as an antiseptic for wounds, skin rash and pruritus. In this study, to validate this antiseptic property, the chemical composition and antimicrobial activity of the essential oil from the flowers of R. raetam was evaluated. The oil was obtained using hydrodistillation and was analysed by gas chromatography-mass spectrometry. The antibacterial activity was achieved using disc diffusion and broth dilution assay against six bacteria species. Analysis of the essential oil revealed the presence of β-linalool (51%), 2-decen-1-ol (6.6%) and limonene (7.4%) as the major components. The results showed significant activity against microorganisms, especially Staphylococcus aureus, with inhibition zones and minimal inhibitory concentration values in the range of 5.0 mm and 3.0 mg mL?1, respectively. The results on the antibacterial activity provide scientific support for the use of these plants in traditional herbal preparations.     

Live cell refractometry using microfluidic devices

Using Hilbert phase microscopy for extracting quantitative phase images, we measured the average refractive index associated with live cells in culture. To decouple the contributions to the phase signal from the cell refractive index and thickness, we confined the cells in microchannels. The results are confirmed by comparison with measurements of spherical cells in suspension.     

Photoelastic optimization of the profiles of Wildhaber-Novikov gears

Wildhaber-Novikov gears having circular flanks hold out a very promising future in the field of gearing for power transmission in very heavily loaded machineries. In order to optimize the profile parameters of these gears, a photoelastic investigation was carried out. Models of Wildhaber-Novikov gears made of photoelastic material, Araldite-D, were used in the investigation. Included were the models with various profile radii and fillet radii at different pressure angles. The flank and bending stresses of these gears were determined in each case and were compared with those of involute gears. From this investigation, it was concluded that the load-carrying capacity of circular-arc gears is 3.5 times that of involute gears. It was found that with profile radius up to 1.5 module, the bending stresses of these gears are lower than those of corresponding involute gears, under identical conditions of loading. It was observed that high pressure angles, when used for Wildhaber-Novikov gears having comparatively smaller profile radii, produce high flank stresses. Gears with larger profile radii, at smaller pressure angles were seen to have a high value for the ratio of flank stress to the bending stress. On the other hand, gears with smaller profile radii, at higher pressure angles, were observed to have a smaller value for this ratio of stresses.     

HPLC Bioassay of Elvitegravir using a Molecularly Imprinted Polymer Based Solid Phase Extraction in RAT Plasma: Application to Pharmacokinetic Studies

Journal of Analytical Chemistry - A water-compatible molecularly imprinted polymer (MIP) was prepared for specific extraction of HIV-1 integrase inhibitor elvitegravir (EVG). It was prepared by a...