Background: Probiotics seems to play a beneficial role in stressed populations; thus, a systematic review and meta‐analysis to assess the effects of probiotics on stress in healthy subjects were conducted.Methods: Randomized controlled trials on the effects of probiotics on stress in healthy subjects were retrieved from five databases. The effects of probiotics on subjective stress level, stress‐related subthreshold anxiety/depression level, cortisol level, and adverse reactions were analyzed. Separate subgroup analyses were conducted on single‐strain probiotics versus multi‐strain probiotics, and short‐term administration versus long‐term administration.Results: Seven studies were included, involving a total of 1,146 subjects. All the studies were rated as low or moderate risk of bias. Our research found that probiotic administration can generally reduce the subjective stress level of healthy volunteers and may improve their stress‐related subthreshold anxiety/depression level, but no significant effect was observed in the subgroup analysis. The effect of probiotics on cortisol level was not significant. Adverse reactions were reported in only one of seven studies, but left undescribed.Conclusion: Current evidence suggests that probiotics can reduce subjective stress level in healthy volunteers and may alleviate stress‐related subthreshold anxiety/depression level, without significant effect on cortisol level, and there is not enough support to draw conclusions about adverse effects; thus, more reliable evidence from clinical trials is needed.

Computer-aided detection technology is less applied in brain tumor detection terminals, and it is difficult to eliminate the influence of various interference factors on the diagnosis results. In order to promote the application of computer-aided detection technology in brain tumor detection, this study based on convolutional neural network, combined with MRI detection technology to construct a model adapted to brain tumor feature detection. The main function of this research model is to segment and recognize MRI brain tumors and use convolutional layer to perform convolution operation to improve recognition efficiency and rate and combine artificially selected features with machine learning features. In addition, this article uses feature fusion to further improve the diagnostic results. Finally, this paper designs experiments to perform performance analysis. The research shows that the model algorithm designed in this paper has certain practical effects and can provide theoretical reference for subsequent related research.

Background: Psychological stress is a ubiquitous subjectively negative emotional experience, but excessive psychological stress has adverse effects on the happiness in our lives and physical and mental health, and may cause many health problems. Studies have found that probiotics have a certain role in alleviating negative emotions, reducing abnormal behaviors, improving cognitive function, and also showing the great potential of probiotics in relieving psychological stress. At present, many clinical trials have been carried out to intervene in populations with psychological stress with probiotic supplements, but there still lack of targeted systematic review and meta-analysis. Methods and analysis: The Cochrane Central Register of Controlled Trials, Embase, MEDLINE, Psycoinfo, Cumulative Index to Nursing and Allied Health Literature will be searched to obtain the eligible randomized controlled trials published up to March 1, 2019. Meanwhile, the references to relevant publications will also be reviewed to identify other studies, and will re-search before finial summary for analysis. EndNote X7 will be used as a document manager for duplicate checking and screening of literature. The risk of bias will be assessed and the date of included studies will be analyzed by Revman V5.3.5. Results: The primary outcome will be subjective stress level, general mild psychiatric symptoms of participants. The secondary outcome will be cortisol level and adverse effects likely to be related to treatment. Conclusion: The systematic review and meta-analysis will provide evidence to assess the efficacy and safety of probiotics in relieving psychological stress. PROSPERO registration number: PROSPERO CRD42019122930.