s. hosseinkhani

A virtual reality platform is presented for teaching simple shapes and alphabetic letters to blind students. By using this technology the teacher could be able to present special letters and shapes on a virtual plate. A virtual plate displays shapes and letters that the blind user can “feel” using a haptic robot that display force from the computer to him/her. This method has been tested in a blind school and the result presented in a paper. Results showed that the virtual environment is a useful educational tool for blind students in case of money and time. As the results showed a blind student with a an average IQ can learn the letter or shape by up to 15 times of repetition and after that he/she can write or draw the shape or letter on the paper.

Pyruvate kinase is a key enzyme in glycolytic pathway that catalyzes the transphosphorylation between phosphoenolpyruvate and ADP to yield ATP and Pyruvate. Geobacillus stearothermophillus has a stable pyruvate kinase with determined crystal structure that composed of four separate domains. Given that limited proteolysis experiments can be successfully used to probe conformational features of proteins, in this study we obtained useful information on Geobacillus pyruvate kinase using limited proteolysis with two proteases that have different substrate specificity and optimum temperature of activity, trypsin and thermolysin. Proteolytic patterns at different temperatures indicate that resulting fragments were the same but the rate of digestion increased with temperature. In the next step, Sucrose and Glycine were used to examine the effects of additives on stability and activity of pyruvate kinase. Limited proteolysis was carried out at 37 °C by trypsin and at 30, 55 and 60 °C in presence of thermolysin, in the absence and presence of different concentrations of sucrose (0– 1.5 M) and glycine (0–1.5 M). We observed that stabilization of pyruvate kinase by this osmolytes is concentration dependent and the rate of limited proteolysis in presence of additives, at temperatures above 60 °C decrease; however, there was no any effect on proteolytic patterns. In all experiments the activity of pyruvate kinase was determined with a couple assay methods by luciferase. A clear correlation was observed between proteolytic digestion and enzyme activity. This study reveals a number of flexible and protease-prone regions of pyruvate kinase that exist regardless of the environmental conditions.