Dr. Jamilah Al-zahrani has completed her PhD at the age of 20 years from King Abdulaziz University (KAU) and Postdoctoral studies from same University. She is the Director of Physics, a premier Bio-Soft service organization. She has published more than 12 papers in reputed journals and has been serving as a lecturer and member of several physics associations in Saudi Arabia. She also attended and participated in many National and International conferences and has received Scientific Publishing awards.
Natural Cosmetics containing plant extracts and minerals are commonly used all over the Arab regions by applying directly to the human skin and hair in order, to clean, improve or change the appearance of them. So, these materials should be safe for health, especially the increasing sale and use of natural cosmetics without available censorship in the presence of dangerous metals or codified instructions. Common natural product samples used as cosmetic materials were collected from various markets in Saudi Arabia, analysed by using a high purity germanium detector (HPGe) to determine radioactivity concentrations of the natural radionuclides 226Ra, 232Th and 40K and to assess the risk present in these materials to human health. The obtained concentrations for 226Ra and 232Th ranged from 0.65±0.17 to 6.47±1.07and from 0.34±0.11 to 8.54±1.16 Bq kg-1, respectively, while the concentration of 40K ranged from 10.62±0.35 to 1202.84±15.95Bq kg-1, with overall mean values of 2.72, 3.73 and 444.09 Bq kg-1 respectively. The mean values of radium equivalent , absorbed dose rate and the annual effective dose of the samples under study were determined as 42.25 Bq kg-1 , 22.58 nGyh-1 and 0.028 mSvy-1, respectively . This work would be useful for establishing baseline data on the gamma background radiation levels in the studied samples for assessment the radiation exposures to the population. It was found that the present results are lower than the permitted limits (UNSEAR2000) and the studied natural samples products are safe to the human usage as cosmetic materials.
Jeimmy C. Ibarra is a chemical engineer and student of Master in Design and Process Management with emphasis in Chemical Processes of the University of La Sabana, Chia, Colombia. He has focused his research in the area of biomaterials with biomedical applications, specifically in polyurethanes synthesized from higuerilla oil as a possible substitute for conventional polyols. This approach responds to the topics of interest of the Energy, Materials and Environment Research Group (GEMA), of which she is a member.
In fields such as biotechnology, it has emerged the need to use materials that help improve current devices and medical procedures. For this reason, new biodegradable polymers with specific properties are increasing their demand. Among the types of polymers used for such purposes, polyurethanes are notable for their versatility and ability to obtain products with a wide range of physical and mechanical properties. In the current work, the effect of the NCO/OH stoichiometric ratio and the chemical structures of hexamethylene (HDI), 1,4-cyclohexane (HMDI) and toluene (TDI) diisocyanates on degradability, cytotoxicity and physicochemical and mechanical properties of polyurethanes obtained from castor oil were studied. Water absorption tests and contact angle measurements were performed to determine the hydrophobic character of the materials; it was found that as the stoichiometric ratio, the flexibility and the intermolecular forces increase, the material is more hydrophobic (TDI>HDI>HMDI). The low absorption capacity is attributed to the hydrophobic nature of the castor oil. An in vitro degradation test was performed for 12 weeks, showing a low percentage of weight loss, directly related to the low diffusion of water within the matrix. MTT assays were used on a mouse fibroblast cell line L929, indicating that the polyurethanes with the NCO/OH stoichiometric ratios of 1.0 have a cell viability greater than 60%, being considered materials with low cytotoxicity, which can be used for biomedical applications.