The combined method for uncertainty evaluation in electromagnetic radiation measurement

Electromagnetic radiation of all frequencies represents one of the most common and fastest growing environmental influence. All populations are now exposed to varying degrees of electromagnetic radiation and the levels will continue to increase as technology advances. An electronic or electrical product should not generate electromagnetic radiation which may impact the environment. In addition, electromagnetic radiation measurement results need to be accompanied by quantitative statements about their accuracy. This is particularly important when decisions about product specifications are taken. This paper presents an uncertainty budget for disturbance power measurements of the equipment as part of electromagnetic radiation. We propose a model which uses a mixed distribution for uncertainty evaluation. The evaluation of the probability density function for the measurand has been done using the Monte Carlo method and a modified least-squares method (combined method). For illustration, this paper presents mixed distributions of two normal distributions, normal and rectangular, respectively

Production of fructose and gluconic acid from sucrose with cross-linked yeast cell walls expressing glucose oxidase on the surface

Saccharomyces cerevisiae, known as bakers’ yeast, is one of the most utilized yeasts in industry. Several enzymes that are naturally produced by yeast, such as invertase and catalase, combined with heterologously expressed glucose oxidase (GOx), represent the enzyme machinery for fructose and gluconic acid production. Therefore, we have used yeast cell walls with expressed glucose oxidase as a platform for crosslinking with invertase and catalase to create biocatalyst cells for the high yield sucrose conversion. Using 5% (w/v) suspension of cross-linked yeast cell walls in 0.15 M sucrose solution, 1.86 g L−1 h−1 of gluconic acid has been obtained using wt-GOx, while mutant A2-GOx produced 2.91 g L−1 h−1 of gluconic acid. Increasing the concentration of modified yeast cells walls to 10% (w/v) we were able to obtain almost 100% conversion of glucose to gluconic acid using A2-GOx in the first cycle. Reusing the modified cells walls in three consecutive cycles, conversion dropped to approximately 70% using A2-GOx and 40% using wt-GOx