Propionic acid promotes the virulent phenotype of Crohn's disease-associated adherent-invasive Escherichia coli

Propionic acid (PA) is a bacterium-derived intestinal antimicrobial and immune modulator used widely in food production and agriculture. Passage of Crohn’s disease-associated adherent-invasive Escherichia coli (AIEC) through a murine model, in which intestinal PA levels are increased to mimic the human intestine, leads to the recovery of AIEC with significantly increased virulence. Similar phenotypic changes are observed outside the murine model when AIEC is grown in culture with PA as the sole carbon source; such PA exposure also results in AIEC that persists at 20-fold higher levels in vivo. RNA sequencing identifies an upregulation of genes involved in biofilm formation, stress response, metabolism, membrane integrity, and alternative carbon source utilization. PA exposure also increases virulence in a number of E. coli isolates from Crohn’s disease patients. Removal of PA is sufficient to reverse these phenotypic changes. Our data indicate that exposure to PA results in AIEC resistance and increased virulence in its presence

A Kinematic Model of the Tibio-Talar Joint Using a Minimum Energy Principle

This work presents a 3D kinematic model for the passive flexion motion of the tibio-talar joint. With only knowledge of the articular surface shapes, the spatial trajectory of passive motion is obtained as the envelop of joint configurations that maximize the surfaces congruence. An increase in joint congruence corresponds to an improved capability of distributing an applied load, allowing the joint to attain better strength with less material. Thus, joint congruence maximization is a simple geometric way to capture the idea of joint energy minimization. The results obtained are compared with in vitro measured trajectories. Preliminary experimental data provide strong support for the predictions of the theoretical model

Transition, the Evolution of Stock Market Efficiency and Entry into EU: The Case of Romania

In this paper we demonstrate that the measurement of stock market efficiency is an important activity in establishing whether eastern European countries satisfy the Copenhagen Criteria for EU membership. Specifically, we argue that developing an efficient stock market should be an important policy focus for countries with aspirations to join the EU as it helps to demonstrate the existence of a functioning market economy. We illustrate this issue by examining the evolution of stock market efficiency in the Bucharest Stock Exchange from mid-1997 to September 2002. We use a GARCH model on daily price data and model the disturbances using the Student-t distribution to allow for ‘fat-tails’. We find strong evidence of inefficiency in the Bucharest Stock Exchange in that the lagged stock price index is a significant predictor of the current price index. This result is robust to the inclusion of variables controlling for calendar effects of the sort that have been observed in more developed stock markets. The level of inefficiency appears to diminish over time and we find evidence consistent with stock market efficiency in Romania after January 2000. Copyright Springer 2005stock market efficiency, transition, G14, P34,