2.4 kW 1045 nm narrow-spectral-width monolithic single-mode CW fiber laser by using an FBG-based MOPA configuration.

A 24 kW narrow-spectral-width near-diffraction-limited monolithic fiber laser system at ${\sim}{1045.2}\;{\rm{nm}}$ in a fiber Bragg grating (FBG)-based master oscillator power amplifier (MOPA) configuration is demonstrated in this paper. The near-diffraction-limited beam quality (${{\rm{M}}^2}\sim{1.2}$) and a spectral width of 0.35 nm (${\sim}{{96}}\;{\rm{GHz}}$) are achieved. The stimulated Raman scattering (SRS) is theoretically and experimentally investigated. The SRS has been suppressed by carefully optimizing the length of the Yb-doped fiber and the pumping scheme, and a signal-to-noise ratio of ${\sim}{{33}}\;{\rm{dB}}$ between the laser signal and the Raman Stokes component is achieved. The stimulate Brillouin scattering and the transverse mode instability are not observed. To our best knowledge, this is the highest-output power for ${{104}} \times {\rm{nm}}$ single-mode fiber laser with ${\sim}{{96}}\;{\rm{GHz}}$ spectral width by using an FBG-based MOPA configuration.

Reducing the inhibitory effect of cigarette smoke on the activity of oral peroxidase by the addition of berberine in cigarette filter.

This study was carried out to evaluate the effect of cigarette smoke (CS) on the activity of oral peroxidase (OPO) after berberine was added to the cigarette filter. Activated carbon fiber (ACF) was chosen to load berberine as a part of the cellulose acetate (CA) filter to obtain the modified B-ACF cigarette filter. Then the effects of CS from the testing cigarettes on the activity of OPO were investigated in vitro by the 2-nitrobenzoic acid assay, and the smoke chemistry was also analyzed, especially the content of hydrogen cyanide (HCN) in the CS. The results indicated that the loss of activity of OPO in B-ACF filter cigarette group decreased by 20% and 25%, compared with those of ACF and CA filter cigarette groups, respectively. The relative residual activity of OPO in B-ACF filter group was increased with the increase of berberine in the filter compared with the CA filter group. It could be observed that the reduction in HCN might be related to the berberine in the cigarette filter, reducing the inhibition of CS on the activity of OPO.

Cytotoxicity and antihyperglycemic effect of minor constituents from Rhizoma Coptis in HepG2 cells.

Generally, berberine, coptisine, palmatine, and jatrorrhizine were considered as the main bio-active compounds in Rhizoma Coptis (RC). Little attention was paid to investigate the pharmacological activity of minor constituents in RC. The present study was designed to separate the minor compounds, and the cytotoxicity and antihyperglycemic effect of these compounds in HepG2 cells were also studied. Palmatine (1), berberine (2), coptisine (3), epiberberine (4), columbamine (5), and jatrorrhizine (6) from RC ethanol extract were isolated by high speed counter current chromatography (HSCCC) in one run. The remaining fraction (about 50% of extract in HSCCC) was further isolated by traditional column chromatography methods to yield magnoflorine (7), ferulic acid (8), and choline (9). Another four alkaloids, namely groenlandicine (10), berberrubine (11), oxyberberine (12), 8-oxo-coptisine (13), also were obtained from CHCl(3) extracts. Especially, choline was first isolated from RC. Cell assay indicated that the minor fractions excluding compounds 1-6 showed obvious glucose lowering activity. In addition, the minor monomers also exhibited moderate glucose lowering activity. The combination of berberine and ferulic acid showed synergistic effect on antihyperglycemic. The combination of alkaloids 1-6 was same so. All compounds had different cytotoxicity in HepG2 cells within the test concentration. Of them, berberrubine showed the strongest cytotoxicity. The results suggested that combined action of variety constituents contributed to the antihyperglycemic effects and low cytotoxicity of RC extract in HepG2 cells.