Background The microbiota–gut–brain axis, especially the microbial tryptophan (Trp) biosynthesis and metabolism pathway (MiTBamp), may play a critical role in the pathogenesis of major depressive disorder (MDD). However, studies on the MiTBamp in MDD are lacking. The aim of the present study was to analyze the gut microbiota composition and the MiTBamp in MDD patients. Methods We performed shotgun metagenomic sequencing of stool samples from 26 MDD patients and 29 healthy controls (HCs). In addition to the microbiota community and the MiTBamp analyses, we also built a classification based on the Random Forests (RF) and Boruta algorithm to identify the gut microbiota as biomarkers for MDD. Results The Bacteroidetes abundance was strongly reduced whereas that of Actinobacteria was significantly increased in the MDD patients compared with the abundance in the HCs. Most noteworthy, the MDD patients had increased levels of Bifidobacterium, which is commonly used as a probiotic. Four Kyoto Encyclopedia of Genes and Genomes (KEGG) orthologies (KOs) (K01817, K11358, K01626, K01667) abundances in the MiTBamp were significantly lower in the MDD group. Furthermore, we found a negative correlation between the K01626 abundance and the HAMD scores in the MDD group. Finally, RF classification at the genus level can achieve an area under the receiver operating characteristic curve of 0.890. Conclusions The present findings enabled a better understanding of the changes in gut microbiota and the related Trp pathway in MDD. Alterations of the gut microbiota may have the potential as biomarkers for distinguishing MDD patients form HCs.

Diabetes mellitus (DM) is one of the primary causes of premature death and disability worldwide. We performed a systematic review and meta-analysis of the published literature regarding the trends in prevalence, awareness, treatment, and control of diabetes mellitus in mainland China. PUBMED, EMBASE, Chinese Biomedical Database, China National Infrastructure database, Chinese Wan Fang database, and Chongqing VIP database were searched. Fifty-six eligible studies were included. Increasing trends in the prevalence, treatment, and control of diabetes in mainland China from 1979 to 2012 were observed. The pooled prevalence, awareness, treatment, and control of diabetes mellitus were 6.41%, 45.81%, 42.54%, and 20.87%, respectively. A higher prevalence of diabetes mellitus was found in urban (7.48%, 95%CI = 5.45~9.50) than rural (6.53%, 95%CI = 4.30~8.76) areas. Furthermore, an increasing chronological tendency was shown in different subgroups of age with regard to the prevalence of diabetes. A higher awareness of DM was found in urban (44.25%, 95%CI = 32.60~55.90) than rural (34.27%, 95%CI = 21.00~47.54) populations, and no significant differences were found in the treatment, and control of diabetes among the subgroups stratified by gender and location. From 1979 to 2012, the prevalence, treatment, and control of diabetes mellitus increased; nevertheless, there was no obvious improvement in the awareness of diabetes.

Ni(x)Co(100-x) (x = 0, 25, 50, 75, and 100) nanoparticles were uniformly in situ grown on reduced graphene oxide (RGO) nanosheets by a coreduction process for the first time. The as-synthesized products were characterized by X-ray powder diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), inductively coupled plasma optical emission spectrometry (ICP-OES), and transmission electron microscopy (TEM). It was found that RGO nanosheets can effectively prevent the aggregation of Ni(x)Co(100-x) nanoparticles. The size and morphology of the Ni(x)Co(100-x) nanoparticles on RGO nanosheets can be slightly adjusted by changing the Ni:Co atomic ratio. The magnetic properties of the RGO-Ni(x)Co(100-x) composites were investigated at 300 and 1.8 K, respectively. The results reveal that the composites have ferromagnetic characteristics and show composition dependent magnetic properties. In addition, these RGO-Ni(x)Co(100-x) nanocomposites also exhibit enhanced catalytic activities toward the reduction of 4-nitrophenol (4-NP) by NaBH(4) as compared with bare Ni(x)Co(100-x) alloy, and the RGO-Ni(25)Co(75) shows the highest catalytic activity among the obtained nanocomposites. This general and facile coreduction route can be extended to synthesize other alloy nanostructures on RGO nanosheets with various morphologies and functions, and provides a new opportunity for the application of graphene-based materials.

With a unique structure and extraordinary properties, graphene has attracted tremendous attention in the preparation of graphene-based composites for various applications. In this study, two different strategies, including in situ growth and a self-assembly approach, have been developed to load CeO2 nanoparticles onto reduced graphene oxide (RGO) nanosheets. The microstructure and morphology of the as-synthesized RGO/CeO2 nanocomposites were investigated by x-ray diffraction, Raman spectroscopy and transmission electron microscopy. The results reveal that CeO2 nanoparticles with well-controlled size and a uniform distribution on RGO sheets with tunable density can be achieved through the self-assembly approach. The significantly enhanced photocatalytic activity of the RGO/CeO2 nanocomposites in comparison with bare CeO2 nanoparticles was revealed by the degradation of methylene blue under simulated sunlight irradiation, which can be attributed to the improved separation of electron-hole pairs and enhanced adsorption performance due to the presence of RGO. A suitable loading content of CeO2 on RGO was found to be crucial for optimizing the photocatalytic activity of the nanocomposites. It is expected that this convenient assembly approach with high controllability can be extended to the attachment of other functional nanoparticles to RGO sheets, and the resultant RGO-supported highly dispersed nanoparticles are attractive for catalysis, sensing and power source applications.

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The ITGA2 gene C807T polymorphism may be a susceptible predictor of the risk of ischemic stroke. More data are needed to elucidate the relationship further.

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