Isochoric cooling of air in the University Physics laboratory

In this paper an alternative way of conducting the physics laboratory exercise for determining the adiabatic index of air using the Clement -- Desormes method is proposed. The process of isochoric cooling of air has been studied in terms of the dependence of pressure on time, and hence temperature on time, since it is proportional to pressure at a constant volume and mass of air. A theoretical model of the considered process was also made. The experimental results were processed statistically. The coefficient of determination $R^2$ and the F-test statistic were calculated and their values indicate a very good agreement between theory and experiment. The analysis of the residuals, however, implies that the model could be further improved through the inclusion of higher order terms.Comment: Accepted for publication in Romanian Reports in Physics, https://rrp.nipne.ro/inpress.htm

A Simple and Powerful Approach for Isolation of Arabidopsis Mutants with Increased Tolerance to H2O2-Induced Cell Death

A genetic approach is described to isolate mutants more tolerant to oxidative stress. A collection of T-DNA activation tag Arabidopsis thaliana mutant lines was screened for survivors under conditions that trigger H2O2-induced cell death. Oxidative stress was induced by applying the catalase (CAT) inhibitor aminotriazole (AT) in the growth media, which results in decrease in CAT enzyme activity, H2O2 accumulation, and subsequent plant death. One mutant was recovered from the screening and named oxr1 (oxidative stress resistant 1). The location of the T-DNA insertion was identified by TAIL-PCR. Oxr1 exhibited lack of cell death symptoms and more fresh weight and chlorophyll content compared to wild type. The lack of cell death correlated with more prominent induction of anthocyanins synthesis in oxr1. These results demonstrate the feasibility of AT as a screening agent for the isolation of oxidative stress-tolerant mutants and indicate a possible protective role for anthocyanins against AT-induced cell death. The chapter includes protocols for ethyl methanesulfonate mutagenesis, mutant screening using AT, T-DNA identification by TAIL-PCR, CAT activity measurements, and determination of malondialdehyde, chlorophyll, and anthocyanins.