Semidiscrete optical vortex droplets in quasi-phase-matched photonic crystals

A new scheme for producing semidiscrete self-trapped vortices (\textquotedblleft swirling photon droplets\textquotedblright ) in photonic crystals with competing quadratic ($\chi ^{(2)}$) and self-defocusing cubic ($\chi ^{(3)}$) nonlinearities is proposed. The photonic crystal is designed with a striped structure, in the form of spatially periodic modulation of the $\chi ^{(2)}$ susceptibility, which is imposed by the quasi-phase-matching technique. Unlike previous realizations of semidiscrete optical modes in composite media, built as combinations of continuous and arrayed discrete waveguides, the semidiscrete vortex droplets are produced here in the fully continuous medium. This work reveals that the system supports two types of semidiscrete vortex droplets, \textit{viz}., onsite- and intersite-centered ones, which feature, respectively, odd and even numbers of stripes, $\mathcal{N}$. Stability areas for the states with different values of $\mathcal{N}$ are identified in the system's parameter space. Some stability areas overlap with each others, giving rise to multistability of states with different $\mathcal{N}$. The coexisting states are mutually degenerate, featuring equal values of the Hamiltonian and propagation constant. An experimental scheme to realize the droplets is outlined, suggesting new possibilities for the long-distance transmission of structured light carrying orbital angular momentum in nonlinear media.Comment: 9 pages, 7 figures, and 82 reference

Isolation and purification of Tartary buckwheat polysaccharides and their effect on gut microbiota

Tartary buckwheat (Fagopyrum tataricum) is rich in polysaccharides that can be utilized by the gut microbiota (GM) and provide several health benefits. However, the mechanisms underlying the action of these polysaccharides remain unclear to date. In this study, Tartary buckwheat polysaccharides (TBP) were purified, and five fractions were obtained. The composition of these fractions was determined using ion chromatography. Different TBP components were investigated regarding their probiotic effect on three species of Bifidobacteria and Lactobacillus rhamnosus. In addition, the effect of TBP on GM and short-chain fatty acids (SCFAs) was evaluated. Results showed that the probiotic effect of TBP fraction was dependent on their composition. The polysaccharides present in different fractions had specific probiotic effects. TBP-1.0, mainly composed of fucose, glucose, and d-galactose, exhibited the strongest proliferation effect on L. rhamnosus, while TBP-W, rich in glucose, d-galactose, and fructose, had the best promoting effect on Bifidobacterium longum and Bifidobacterium adolescentis growth. Furthermore, TBP-0.2, composed of d-galacturonic acid, d-galactose, xylose, and arabinose, exhibited its highest impact on Bifidobacterium breve growth. The composition of GM was significantly altered by adding TBP during fecal fermentation, with an increased relative abundance of Lactococcus, Phascolarctobacterium, Bacteroidetes, and Shigella. Simultaneously, the level of SCFA was also significantly increased by TBP. Our findings indicate that Tartary buckwheat can provide specific dietary polysaccharide sources to modulate and maintain GM diversity. They provide a basis for Tartary buckwheat commercial utilization for GM modulation

The pattern of duck sternal ossification and the changes of histological structure and gene expression therein

ABSTRACT: As the largest single bone, avian sterna are very different from those of mammals in terms of morphology and functions. Moreover, years of artificial selection in poultry led to incomplete sternal ossification at slaughter age, which may cause diseases, sternal injury, and restriction to breast muscle growth. However, in living birds, studies have rarely described the ossification pattern and underlying mechanisms of the sterna. Here, we examined the pattern (timeline, ossification centers, ossification directions, weekly changes of different parts, quantified differences in ossification degree among sexes and parts) and developmental changes (histological structure, gene expression) of postnatal duck sternal ossification. Direct observation and alcian blue and alizarin red staining of whole sterna samples revealed that, duck sterna mainly ossified during 5 to 9 wk old with five ossification centers. These centers and their ossification directions were different from and more complex than the previously studied birds. The weekly changes of sterna and the quantitative analysis of ossification-related traits showed that ossifications in the three parts of duck sterna (sternum body, keel, posterolateral processes) were mutually independent in space and time, meanwhile, the male duck sterna were more late-maturing than the female. The results of hematoxylin-eosin, alcian blue, and toluidine blue stainings and the expression levels of COL2A1, COL10A1, COL1A2, and CTSK together supported that, duck sternal ossification was highly similar to typical endochondral ossification. Furthermore, continuously high expression of MMP13 and SPARC and their significant (P < 0.05) co-expression with COL2A1, COL10A1, COL1A2, and CTSK suggested the importance of MMP13 and SPARC in duck sternal ossification. Taken together, our results may be helpful for the understanding of avian sternal ossification and the improvement of the performance and welfare of poultry from a new perspective

Integrated Transcriptome and Metabolome Analysis Reveals the Regulatory Mechanisms of <i>FASN</i> in <i>Geese</i> Granulosa Cells

FASN plays a critical role in lipid metabolism, which is involved in regulating ovarian follicular development. However, the molecular mechanisms of how FASN regulate the function of ovarian follicular cells still remain elusive. In this study, by overexpression or interference of FASN in pre-hierarchical follicle granulosa cells (phGCs) and hierarchical follicle granulosa cells (hGCs), we analyzed their effects on the granulosa cell transcriptome and metabolome profiles using RNA-Seq and LC-MS/MS, respectively. The results showed that overexpression of FASN promoted proinflammatory factors expression by activating TLR3/IRF7 and TLR3/NF-κB pathways in phGCs, but only by activating TLR3/IRF7 pathways in hGCs. Then, necroptosis and apoptosis were triggered through the JAK/STAT1 pathway (induced by inflammatory factors) and BAK/caspase-7 pathway, respectively. The combined analysis of the metabolome and transcriptome revealed that FASN affected the demand of GCs for 5-hydroxytryptamine (5-HT) by activating the neuroactive ligand-receptor interaction pathway in two categorized GCs and only altering the metabolic pathway of tryptophan in phGCs, and ultimately participated in regulating the physiological function of geese GCs. Taken together, this study showed that the mechanisms of FASN regulating the physiological function of geese phGCs and hGCs were similar, but they also had some different characteristics