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BackgroundThe intestinal microbiota disorder gradually aggravates during the progression of diabetes. Dapagliflozin (DAPA) can improve diabetes and diabetic kidney disease(DKD). However, whether the gut microbiota plays a role in the protection of DAPA for DKD remains unclear.MethodsTo investigate the effects of DAPA on DKD and gut microbiota composition during disease progression, in our study, we performed 16S rRNA gene sequencing on fecal samples from db/m mice (control group), db/db mice (DKD model group), and those treated with DAPA (treat group) at three timepoints of 14weeks\18weeks\22weeks.ResultsWe found that DAPA remarkably prevented weight loss and lowered fasting blood glucose in db/db mice during disease progression, eventually delaying the progression of DKD. Intriguingly, the study strongly suggested that there is gradually aggravated dysbacteriosis and increased bile acid during the development of DKD. More importantly, comparisons of relative abundance at the phylum level and partial least squares-discriminant analysis (PLS-DA) plots roughly reflected that the effect of DAPA on modulating the flora of db/db mice increased with time. Specifically, the relative abundance of the dominant Firmicutes and Bacteroidetes was not meaningfully changed among groups at 14 weeks as previous studies described. Interestingly, they were gradually altered in the treat group compared to the model group with a more protracted intervention of 18 weeks and 22 weeks. Furthermore, the decrease of Lactobacillus and the increase of norank_f:Muribaculaceae could account for the differences at the phylum level observed between the treat group and the model group at 18 weeks and 22 weeks.ConclusionWe firstly found that the protective effect of DAPA on DKD may be related to the dynamic improvement of the gut microbiota over time, possibly associated with the impact of DAPA on the bile acid pool and its antioxidation effect.

In order to expand the possibility of better applicability, spheroid particles are adopted to replace the traditional spherical particle assumption in the modeling of multi-wavelength light extinction method. The extinction coefficient and extinction spectrum are then calculated at different axial ratios based on the generalized Mie theory. Combining extinction spectrum with regularized inversion algorithm, the effect of particle shape on particle size characterization in multi-wavelength extinction method is discussed in detail. The results show that in the visible light range, for submicron particles with a refractive index of 1.33, inversed particle sizes are compared with the sphere, which yields the equivalent volume spheroid in axial ratio of 1-3 particle size inversion error within 10%, while, when the ratio is above 3, the relative deviation may reach about 50%. It can be seen that for particles of equal volume, the spheroidal shape exerts a great influence on the particle size measurement of the multi-wavelength extinction method, and the assumption of spheroidal particle is more suitable for the cases of axial ratio within 3.

This work present a multi-pathlight extinction approach to determine the oil mist filter efficiency based on measuring the concentration and size distribution of oil particles. Light extinction spectrum(LES) technique was used to retrieve the oil particle size distribution and concentration. The multi-path measuring cell was designed to measure low concentration and fine particles after filtering. The path-length of the measuring cell calibrated as 200 cm. The results of oil particle size with oil mist filtering were obtained as D32 = 0.9μm. Cv=1.6×10−8.