Dendrobium officinale Kimura et Migo and American ginseng mixture: A Chinese herbal formulation for gut microbiota modulation.

Dendrobium officinale Kimura et Migo (D. officinale) is a famous traditional Chinese medicine (TCM). A mixture of D. officinale and American ginseng has been shown to enhance cell-mediated immunity, humoral immunity, and monocyte/macrophage functions in mice. Here, the effects of a D. officinale and American ginseng mixture on the structure of gut microbial community in dogs were examined using high-throughput 16S rRNA gene amplicon sequencing. The data revealed that while the mixture did not change the diversity of gut microbial community significantly, differences among individuals were significantly reduced. Furthermore, the mixture-responsive operational taxonomic units (OTUs) exhibited a phase-dependent expression pattern. Fifty-five OTUs were found to exhibit a mixture-induced expression pattern, among which one third were short-chain fatty acid (SCFA)-producing genera and the others were probiotic genera included Lactobacillus spp., Sutterella, Alistipes, Anaerovorax, Bilophila, Coprococcus, Gordonibacter, Oscillibacter, among others. By contrast, 36% of the OTUs exhibiting a mixture-repressed expression pattern were disease-associated microorganisms, and six genera, namely Actinomyces, Escherichia/Shigella, Fusobacterium, Slackia, Streptococcus and Solobacterium, were associated with cancer. In addition, five genera were closely associated with diabetes, namely Collinsella, Rothia, Howardella, Slackia and Intestinibacter. Our results indicate that this D. officinale and American ginseng mixture may be used as a prebiotic agent to enhance SCFA-producing genera and prevent gut dysbiosis.

Surface-Induced ARGET ATRP for Silicon Nanoparticles with Fluorescent Polymer Brushes.

Well-defined polymer brushes attached to nanoparticles offer an elegant opportunity for surface modification because of their excellent mechanical stability, functional versatility, high graft density as well as controllability of surface properties. This study aimed to prepare hybrid materials with good dispersion in different solvents, and to endow this material with certain fluorescence characteristics. Well-defined diblock copolymers poly (styrene)-b-poly (hydroxyethyl methyl acrylate)-co-poly (hydroxyethyl methyl acrylate- rhodamine B) grafted silica nanoparticles (SNPs-g-PS-b-PHEMA-co-PHEMA-RhB) hybrid materials were synthesized via surface-initiated activators regenerated by electron transfer atom transfer radical polymerization (SI-ARGET ATRP). The SNPs surfaces were modified by 3-aminopropyltriethoxysilane (KH-550) firstly, then the initiators 2-Bromoisobutyryl bromide (BIBB) was attached to SNPs surfaces through the esterification of acyl bromide groups and amidogen groups. The synthetic initiators (SNPs-Br) were further used for the SI-ARGET ATRP of styrene (St), hydroxyethyl methyl acrylate (HEMA) and hydroxyethyl methyl acrylate-rhodamine B (HEMA-RhB). The results indicated that the SI-ARGET ATRP initiator had been immobilized onto SNPs surfaces, the Br atom have located at the end of the main polymer chains, and the polymerization process possessed the characteristic of controlled/"living" polymerization. The SNPs-g-PS-b-PHEMA-co-PHEMA-RhB hybrid materials show good fluorescence performance and good dispersion in water and EtOH but aggregated in THF. This study demonstrates that the SI-ARGET ATRP provided a unique way to tune the polymer brushes structure on silica nanoparticles surface and further broaden the application of SI-ARGET ATRP.

Controlling transverse shift of the reflected light via high refractive index with zero absorption.

We present a theoretical investigation on controlling the transverse shift while most of the researches are on longitudinal Goos-Hänchen shift. A two-layer system is considered. The refractive index of the first layer is fixed. The second layer is an atomic system coupled by a strong laser field to realize the Λ-style electromagnetically induced transparency, and an additional microwave field drives the transition between the lower two levels to construct high refractive index with zero absorption. We use such phenomenon to modify the refractive index, and consequently the transverse shift in reflection. The properties of the atomic system and the transverse shift of reflected field are briefly studied. Our investigation shows that the shift can be tuned by the strength of the microwave field. And since the atomic system is quite sensitive to the phase of the light fields, through which the transverse shift can be manipulated effectively. More importantly, the absorption is limited due to the presence of the microwave field.