Sound Control-Flow Graph Extraction for Java Programs with Exceptions

We present an algorithm to extract control-flow graphs from Java bytecode, considering exceptional flows. We then establish its correctness: the behavior of the extracted graphs is shown to be a sound over-approximation of the behavior of the original programs. Thus, any temporal safety property that holds for the extracted control-flow graph also holds for the original program. This makes the extracted graphs suitable for performing various static analyses, in particular model checking. The extraction proceeds in two phases. First, we translate Java bytecode into BIR, a stack-less intermediate representation. The BIR transformation is developed as a module of Sawja, a novel static analysis framework for Java bytecode. Besides Sawja’s efficiency, the resulting intermediate representation is more compact than the original bytecode and provides an explicit representation of exceptions. These features make BIR a natural starting point for sound control-flow graph extraction. Next, we formally define the transformation from BIR to control-flow graphs, which (among other features) considers the propagation of uncaught exceptions within method calls. We prove the correctness of the two-phase extraction by suitably combining the properties of the two transformations with those of an idealized control-flow graph extraction algorithm, whose correctness has been proved directly. The control-flow graph extraction algorithm is implemented in the \textsc{ConFlEx} tool. A number of test-cases show the efficiency and the utility of the implementation

The effect of calcium on the adhesion of Streptococcus mutans to Human Gingival Epithelial Cells in the presence of probiotic bacteria Lactobacillus plantarum and Lactobacillus salivarius

Introduction: Oral pathogens are among the most common bacterial infections in humans. The adhesion of probiotic bacteria to epithelial cells plays an important role in inhibiting the growth and binding of pathogenic bacteria. We aim to investigate the effect of calcium carbonate on the binding of Streptococcus mutans to Human Gingival Epithelial Cells (HGECs) in the presence of the probiotic bacteria Lactobacillus plantarum and Salivarius. Methods and materials: Experiments are performed in the presence of calcium and probiotic bacteria and HGECs in duplicate and three times separately. The difference in the amount of Streptococcus mutans in HGECs is determined by the presence and absence of Lactobacillus plantarum or salivarius and calcium or both by dilution and culture procedures. Results: Simple effects analysis showed that the survival rate of HGECs in all doses was significantly higher than negatives (p < .001). The results indicated that the survival rate in the single dose of L. salivarius (0.617 ± 0.003) and L. plantarum (0.652 ± 0.002) was significantly higher than the combined doses. Conclusion: This study clearly demonstrates that calcium and probiotics from Lactobacillus salivarius and plantarum alone can improve the survival of HGECs in the presence of Streptococcus mutans. But the combined function of these therapeutic factors is not optimal and even reduces their therapeutic efficacy. © 202