Dynamic scaling of diffusion-limited reactions over fractal surfaces: computer simulation

Abstract Computer simulations are performed to examine the effect of geometrical heterogeneity on chemical reaction occurring over a fractal surface of diffusion-limited aggregation (DLA). Eley-Rideal diffusion-limited reaction (DLA) is chosen as our model reaction system. Dynamic scaling theory, developed for surface growth model, is applied in this work on chemical reaction model revealing two order parameters, a and b, in different time domains, i.e. a ¼ À0:74, b ¼ À0:48 for perfect sticking cases, and a ¼ À0:72, b ¼ À0:5 for cases of lower sticking probability. Surfaces of different fractal dimensions are also considered, where the values of b in both cases and a values in the perfect sticking case do not change obviously. In the cases of lower sticking probability, a values are decreased when fractal dimension approaches to 2. Comparisons are made to the surface roughening model where both order parameters are positive.

Basal leakage in oscillation: Coupled transcriptional and translational control using feed-forward loops.

The circadian clock is a complex system that plays many important roles in most organisms. Previously, many mathematical models have been used to sharpen our understanding of the Arabidopsis clock, which brought to light the roles of each transcriptional and post-translational regulations. However, the presence of both regulations, instead of either transcription or post-translation, raised curiosity of whether the combination of these two regulations is important for the clock's system. In this study, we built a series of simplified oscillators with different regulations to study the importance of post-translational regulation (specifically, 26S proteasome degradation) in the clock system. We found that a simple transcriptional-based oscillator can already generate sustained oscillation, but the oscillation can be easily destroyed in the presence of transcriptional leakage. Coupling post-translational control with transcriptional-based oscillator in a feed-forward loop will greatly improve the robustness of the oscillator in the presence of basal leakage. Using these general models, we were able to replicate the increased variability observed in the E3 ligase mutant for both plant and mammalian clocks. With this insight, we also predict a plausible regulator of several E3 ligase genes in the plant's clock. Thus, our results provide insights into and the plausible importance in coupling transcription and post-translation controls in the clock system

Interplay between ceRNA and Epigenetic Control of microRNA: Modelling Approaches with Application to the Role of Estrogen in Ovarian Cancer

MicroRNAs (miRNAs) play an important role in gene regulation by degradation or translational inhibition of the targeted mRNAs. It has been experimentally shown that the way miRNAs interact with their targets can be used to explain the indirect interactions among their targets, i.e., competing endogenous RNA (ceRNA). However, whether the protein translated from the targeted mRNAs can play any role in this ceRNA network has not been explored. Here we propose a deterministic model to demonstrate that in a network of one miRNA interacting with multiple-targeted mRNAs, the competition between miRNA-targeted mRNAs is not sufficient for the significant change of those targeted mRNA levels, while dramatic changes of these miRNA-targeted mRNAs require transcriptional inhibition of miRNA by its target proteins. When applied to estrogen receptor signaling pathways, the miR-193a targets E2F6 (a target of estrogen receptor), c-KIT (a marker for cancer stemness), and PBX1 (a transcriptional activator for immunosuppressive cytokine, IL-10) in ovarian cancer, such that epigenetic silencing of miR-193a by E2F6 protein is required for the significant change of c-KIT and PBX1 mRNA level for cancer stemness and immunoevasion, respectively, in ovarian cancer carcinogenesi

Pharmacogenomic Prediction of Bleomycin-Induced Pneumonitis in South East Asian Hodgkin Lymphoma Patients

10.1182/blood-2018-99-11395260th Annual Meeting of the American-Society-of-Hematology (ASH)132Supplement