Effects of probiotics on central nervous system functions in humans

Gut microbiota plays an important role in the gut-brain axis. Symbiosis of the gut microbiota maintains the physiological integrity of the host so as to ensure the normal functions of the gut and the brain. Probiotics have beneficial effects on both, physical and mental health, when administered in adequate amount. Thus, probiotics are considered as “psychobiotics”, for their effects on central nervous system functions such as stress-related mental disorders and memory abilities, through the gut-brain axis. However, the efficacy of the probiotics on these central functions was in need to be systematically summarized. While there is a host of animal studies on microbiota, it has not yet been studied much how and where in the brain of humans they unfold their effects. Furthermore, antibiotics, having effects on commensal gut bacteria by eliminating and inhibiting them, have so far not been studied for their role in affecting brain functions. In the current thesis, I performed two literature reviews and two experimental studies on central effects of pro- and antibiotics. The first review systematically analyzed previous research studying the effects of probiotics on central nervous system functions in both, animals and humans. The review concluded the most efficient probiotic interventions and evaluated the possibility of translating preclinical studies to clinical trials. In the second review, we aimed to evaluate the feasibility of a socio-psychological paradigm (Cyberball game) to be used in the following experimental studies with neuroimaging methods and manipulations of the GM. We examined the current neuroimaging literature employing the Cyberball game to induce social stress and feelings of exclusion. The review was intended to generate a framework describing neural processes during the stress. Following the results of the two reviews, we conducted two clinical trials, to investigate effects of antibiotic rifaximin and probiotic Bifidobacterium longum 1714 on neural activations during resting state and during the Cyberball game by using magnetoencephalography. In both studies, the stress induced by the Cyberball game enhanced oscillatory brain activity in different areas and in different frequency bands. Both, rifaximin and probiotics had effects on specific neural oscillatory activities in response to the social stress – rifaximin improved subjects’ relaxation status by reducing frontal and cingulate beta-1 band power, and B.longum 1714 enhanced emotion regulation process by increasing frontal and cingulate theta and alpha bands power. In addition, during the resting state, rifaximin favored individuals’ relaxation status by increasing frontal alpha band power, and B.longum 1714 increased subject’s arousal state by increasing theta band power in frontal and cingulate cortex and reducing the beta-3 band power in hippocampus and temporal cortex. Rifaximin and B.longum 1714, both showed neural effects on the stress response through an “eubiotic” effect, which refers to a healthy balance of the micro-flora in the gastrointestinal tract. Our results provide evidence for gut microbiota alerting CNS functions. Both, reviews and experimental work give clues for further studies targeting the underlying mechanisms of interaction between gut microbiota and CNS function using neuroimaging in patients with psychiatric disorders or gastrointestinal diseases

Determinants of Polarized Sales Distribution in E-market: C2C Mobile Phone Market Scenario of China

The factors influencing huge divisions of wealth in society are widely studied by researchers. However, with the rapid development of the Internet, whether polarization or equalization of market shares exists in e-market among sellers springing up online, and how e-commerce affects its formation is still unknown to us. With a seller sample retrieved from Taobao, our study examines the polarization phenomenon and explores the determinants of its formation in the context of online markets. The descriptive analysis suggests a polarized phenomenon exists in e-commerce. Then this study applies quantile regression approach to investigate the factors that influence the formation of polarization in C2C mobile phone market. The results indicate that, a polarized sales distribution is existed; reputation and negative ratio play more important roles, while the number of items has a lower influence gradually. The empirical results can help us find the reason of polarization in C2C e-market

Ultrasonic Surface Strengthening of Train Axle Material 30CrMoA

AbstractAs hardness of the work-surface working in the train axle has a direct relationship to train axle's life-time, a surface strengthening technology is necessary to strengthen the hardness of the work-surface. In this study, ultrasonic surface strengthening (USS) method was proposed, and its fundamental characteristics were investigated experimentally. Concretely, the influence of many principal parameters, namely workpiece rotational speed n, feed rate f and extrusion amonut P of the tool, on the train axle with material 30CrMoA were investigated. The experiment results show that (1) surface roughness decreases significantly after USS, and lowest surface roughness can be obtained under the condition of rotational speed n=610 r/min, feed rate f=0.2mm/r and extrusion amount P=130μm; (3) hardness after USS bigger than that of before USS up to 24%, under the condition of rotational speed n=610 r/min, feed rate f=0.2mm/r and extrusion amount P=180μm; (4) the residual stress value can be adjusted after USS, the value of residual stress in the work-surface can reach -950Mpa after USS and the depth of the residual compressive stress layer can reach nearly 2mm. This study confirmes that the unltrasonic strengthening technology is a highly effective processing method for improving the surface quality of train axle

Comparison of ductility reduction factors for MDOF flexure-type and shear-type systems

This research investigates the difference of seismic ductility reduction factors between flexure-type and shear-type multi-degree-freedom (MDOF) systems. Multi-mass column cantilever systems are employed to simulate flexure-type shear-wall structure, while multi-mass series spring connection systems are used to simulate shear-type frame structure. Four earthquake records in hard soil site are employed to conduct nonlinear dynamic time history analysis. The effects of storey displacement ductility and vibration period on the seismic ductility reduction factors for flexure-type structure are studied, and the ductility reduction factors between flexure-type and shear-type structures are compared. The results show that the ductility reduction factors for flexure-type structure are about 40 % larger than those for flexure-type structure. Meanwhile, storey displacement ductility and storey number are important factors on seismic ductility reduction factors

Indomethacin inhibits PGE2, regulates inflammatory response, participates in adipogenesis regulation, and improves success rate of fat transplantation in C57/B6 mice

Purpose: To investigate the effect of indomethacin on prostaglandin E2, regulation of inflammation and adipogenesis, and success of fat transplantation in mice. Methods: The mice were randomly divided into 4 groups: group A (free fat group), group B (free fat + stromal vascular fragments group (SVF)), group C (free fat + 200 μM indomethacin group), and group D (free fat + 200 μM indomethacin + SVF group), with 21 mice in each group. Expression levels of adipogenic genes CEBP-α, FABP4 and LPL in each group were determined. Changes in PGE2 level in transplanted adipose tissue, and changes in the expression of NF-κB in apoptotic stem cells induced by different pro-inflammatory treatments were assayed. Results: Compared with group B, the expression levels of adipogenic genes CEBP-α, FABP4 and LPL significantly decreased in groups A, C and D, with group A as the lowest (p < 0.05). Compared with the indomethacin treatment group, the level of inhibition of PGE2 in mice adipose tissue in the indomethacin-free group increased significantly (p < 0.01). The expression of NF-κB in the adipose stem cells from the indomethacin-treated group was significantly lower than that in the indomethacin-treated group after pretreatment with IL-17 or INF-γ + TNF-α. Conclusion: Indomethacin regulates adipogenesis by inhibiting the production of COX2 metabolite, PGE2. It also regulates the local microenvironment, inhibits the inflammatory process, and protects various stem cells. Therefore, it may improve the success rate of fat transplantation

Islanding Detection for Microgrid Based on Frequency Tracking Using Extended Kalman Filter Algorithm

Islanding detection is essential for secure and reliable operation of microgrids. Considering the relationship between the power generation and the load in microgrids, frequency may vary with time when islanding occurs. As a common approach, frequency measurement is widely used to detect islanding condition. In this paper, a novel frequency calculation algorithm based on extended Kalman filter was proposed to track dynamic frequency of the microgrid. Taylor series expansion was introduced to solve nonlinear state equations. In addition, a typical microgrid model was built using MATLAB/SIMULINK. Simulation results demonstrated that the proposed algorithm achieved great stability and strong robustness in of tracking dynamic frequency