mance of CDs, novel methods have been proposed. Element doping is considered one of the effective strategies for improved fluorescence QYs. Sun et al. used a series of N-containing bases to synthesize nitrogen-doped CDs with a QY of 94%. [22] Yang and his colleagues condensed citric acid with ethylenediamine to obtain CDs with a QY of up to 80%. [23] Naumov et al. used glucosamine hydrochloride and thiourea as precursors to synthesize nitrogensulfur co-doped graphene quantum dots with a QY of 60%. [24] Nevertheless, obtaining long-wavelength emission CDs and multicolor emission CDs is still difficult. To this end, researchers have proposed another strategy, that is, to purify CDs or obtain multicolor CDs by adjusting the type and ratio of the solvents through a chromatographic column. Jiang and co-workers used three isomers of phenylenediamine as precursors to obtain blue, green, and red CDs and purified them by silica gel column chromatography. [25] Xiong et al. used silica gel column chromatography to separate the reaction solution and obtained CDs with visible light emissions. [26] Usually, the multicolor CDs obtained by silica column chromatography have a narrow emission wavelength range, and the QY is greatly improved, which provides conditions for the further application of CDs.However, column chromatography requires many organic solvents, which are cumbersome and time-consuming and easily cause CD loss. Therefore, the direct determination of polychromatic CDs by controlling various preparation conditions instead of silica column chromatography has become a popular research topic in recent years. Fan and co-workers reported a method for preparing multicolor CDs. They used two isomers of diaminonaphthalene and citric acid as precursors to obtain five-color CDs by controlling the reaction time or adding sulfuric acid. [27] Sun et al. obtained a series of CDs with different emission colors by adjusting the reaction temperature and the ratio of citric acid to urea. [28] In these reports, two conditions need to be adjusted simultaneously to obtain poly chromatic CDs, which requires more steps and makes the synthesis process time-consuming.In this study, a simple method for preparing multicolor CDs only by controlling the ratio of reactants in the asparagine (Asn) and p-phenylenediamine reaction system was proposed. To the In a reaction system of asparagine and p-phenylenediamine, blue, green, orange, and red carbon dots (CDs) are successfully prepared by adjusting the ratio of the two reactants. The obtained multicolor CDs have excellent stable properties and high fluorescence quantum yields (up to 74%). Clarifying the luminescence mechanism of multicolor CDs is based on the investigation of the composition, structure, and fluorescence properties of the CDs combined with quantum chemistry calculations. A high-quality white light-emitting diode (LED) with CIE color coordinates (0.33, 0.33) is successfully fabricated using a multicolor CD-epoxy resin composite, and its color temperature and color rendering index a...

The woman’s gut microbiota during pregnancy may support nutrient acquisition, is associated with diseases, and has been linked to infant health. However, there is limited information on gut microbial characteristics and dependence in pregnant women. In this study, we provide a comprehensive overview of the gut microbial characteristics of 1479 pregnant women using 16S rRNA gene sequencing of fecal samples. We identify a core microbiota of pregnant women, which displays a similar overall structure to that of age-matched nonpregnant women. Our data show that the gestational age-associated variation in the gut microbiota, from the ninth week of gestation to antepartum, is relatively limited. Building upon rich metadata, we reveal a set of exogenous and intrinsic host factors that are highly correlated with the variation in gut microbial community composition and function. These microbiota covariates are concentrated in basic host properties (e.g., age and residency status) and blood clinical parameters, suggesting that individual heterogeneity is the major force shaping the gut microbiome during pregnancy. Moreover, we identify microbial and functional markers that are associated with age, pre-pregnancy body mass index, residency status, and pre-pregnancy and gestational diseases. The gut microbiota during pregnancy is also different between women with high or low gestational weight gain. Our study demonstrates the structure, gestational age-associated variation, and associations with host factors of the gut microbiota during pregnancy and strengthens the understanding of microbe–host interactions. The results from this study offer new materials and prospects for gut microbiome research in clinical and diagnostic fields.

No abstract

Background Fat grafting, as a standard treatment for numerous soft tissue defects, remains unpredictable and technique-dependent. Human adipose-derived stem cells (hADSCs) are promising candidates for cell-assisted therapy to improve graft survival. As free-living fat requires nutritional and respiratory sources to thrive, insufficient and unstable vascularization still impedes hADSC-assisted therapy. Recently, cytotherapy combined with modified mRNA (modRNA) encoding vascular endothelial growth factor (VEGF) has been applied for the treatment of ischemia-related diseases. Herein, we hypothesized that VEGF modRNA (modVEGF)-engineered hADSCs could robustly enhance fat survival in a fat graft transplantation model. Methods hADSCs were acquired from lipoaspiration and transfected with modRNAs. Transfection efficiency and expression kinetics of modRNAs in hADSCs were first evaluated in vitro. Next, we applied an in vivo Matrigel plug assay to assess the viability and angiogenic potential of modVEGF-engineered hADSCs at 1 week post-implantation. Finally, modVEGF-engineered hADSCs were co-transplanted with human fat in a murine model to analyze the survival rate, re-vascularization, proliferation, fibrosis, apoptosis, and necrosis of fat grafts over long-term follow-up. Results Transfections of modVEGF in hADSCs were highly tolerable as the modVEGF-engineered hADSCs facilitated burst-like protein production of VEGF in both our in vitro and in vivo models. modVEGF-engineered hADSCs induced increased levels of cellular proliferation and proangiogenesis when compared to untreated hADSCs in both ex vivo and in vivo assays. In a fat graft transplantation model, we provided evidence that modVEGF-engineered hADSCs promote the optimal potency to preserve adipocytes, especially in the long-term post-transplantation phase. Detailed histological analysis of fat grafts harvested at 15, 30, and 90 days following in vivo grafting suggested the release of VEGF protein from modVEGF-engineered hADSCs significantly improved neo-angiogenesis, vascular maturity, and cell proliferation. The modVEGF-engineered hADSCs also significantly mitigated the presence of fibrosis, apoptosis, and necrosis of grafts when compared to the control groups. Moreover, modVEGF-engineered hADSCs promoted graft survival and cell differentiation abilities, which also induced an increase in vessel formation and the number of surviving adipocytes after transplantation. Conclusion This current study demonstrates the employment of modVEGF-engineered hADSCs as an advanced alternative to the clinical treatment involving soft-tissue reconstruction and rejuvenation.