Relevance of Stress and Female Sex Hormones for Emotion and Cognition

There are clear sex differences in incidence and onset of stress-related and other psychiatric disorders in humans. Yet, rodent models for psychiatric disorders are predominantly based on male animals. The strongest argument for not using female rodents is their estrous cycle and the fluctuating sex hormones per phase which multiplies the number of animals to be tested. Here, we will discuss studies focused on sex differences in emotionality and cognitive abilities in experimental conditions with and without stress. First, female sex hormones such as estrogens and progesterone affect emotions and cognition, contributing to sex differences in behavior. Second, females respond differently to stress than males which might be related to the phase of the estrous cycle. For example, female rats and mice express less anxiety than males in a novel environment. Proestrus females are less anxious than females in the other estrous phases. Third, males perform in spatial tasks superior to females. However, while stress impairs spatial memory in males, females improve their spatial abilities, depending on the task and kind of stressor. We conclude that the differences in emotion, cognition and responses to stress between males and females over the different phases of the estrous cycle should be used in animal models for stress-related psychiatric disorders

Evaluation of stimulated reservoir volume in laboratory hydraulic fracturing with oil, water and liquid carbon dioxide under microscopy using the fluorescence method

© 2017, Springer International Publishing AG. In shale gas industry, it is desired to develop new reservoir fracturing and enhanced gas recovery technologies to replace the conventional hydraulic fracturing (HF), in order to reduce water usage to guarantee the environmental sustainability and boost individual well production. As the goal of HF is to create high conductivity fracturing networks as flow paths for gas, it is necessary for HF to activate and connect existing natural fractures to generate large fractures network. The success or failure of HF often depends on the stimulated reservoir volume (SRV) which is characterized by the quantity and the quality of the fractures network resulted. This study investigates the micro-fractures network resulted in laboratory HF experiments in 2-D thin polished section by using a fluorescent method supported by advanced computerized image analysis. To evaluate difference of resulted SRV due to the difference of fracturing fluid, using three cylindrical shale cores and three granite cubes having fractures induced by HF using three fluids having different viscosity; oil, water and liquid carbon dioxide (L-CO2). The observation and statistical analysis of fractures induced in HF by the three different fluid viscosities using the fluorescent method showed ability of L-CO2 injection to achieve effective stimulation. The results suggest that employing a low viscosity fluid in HF of shale reservoirs can achieve more productive network with better SRV. In addition, the observation seems to be consistent with the tendency observed in the previous researches

Nutrition and gastrointestinal microbiota, microbial-derived secondary bile acids, and cardiovascular disease

Purpose of review: The goal is to review the connection between gut microbiota and cardiovascular disease, with specific emphasis on bile acids, and the influence of diet in modulating this relationship. Recent findings: Bile acids exert a much broader range of biological functions than initially recognized, including regulation of cardiovascular function through direct and indirect mechanisms. There is a bi-directional relationship between gut microbiota modulation of bile acid-signaling properties, and their effects on gut microbiota composition. Evidence, primarily from rodent models and limited human trials, suggest that dietary modulation of the gut microbiome significantly impacts bile acid metabolism and subsequently host physiological response(s). Available evidence suggests that the link between diet, gut microbiota, and CVD risk is potentially mediated via bile acid effects on diverse metabolic pathways. However, further studies are needed to confirm/expand and translate these findings in a clinical setting