Isolation of Stilbenoids and Lignans from Dendrobium hongdie

Purpose: To isolate and characterize chemical compounds of biological importance from the whole plant of Dendrobium hongdie.Methods: The whole plants of Dendrobium hongdie was extracted with ethanol (EtOH) and separated using silica gel, Sephadex LH-20 and MCI gel to isolate the pure compounds. Characterization of the isolated compounds was achieved using 1H and 13C nuclear magnetic resonance spectroscopy (NMR) and mass spectrometry (MS).Results: Nine compounds including two phenanthrenes, three bibenzyls, a phenanthraquinone, two lignans and a sterol were isolated from the extract. The structures of the compounds were elucidated as nudol (1), gigantol (2), batatasin III (3), tristin (4), moscatin (5), ephemeranthoquinone (6), (-)- syringaresinol (7), liriodendrin (8) and β-sitosterol (9).Conclusion: Nine compounds have been successfully isolated from D. hongdie for the first time. This plant is a potential source of some useful phytochemicals.Keywords: Dendrobium hongdie, Isolation, Stilbenoids, Lignans, Phytochemical

Association of Exposure to Particular Matter and Carotid Intima-Media Thickness: A Systematic Review and Meta-Analysis

Background: Long time exposure to particular matter has been linked to myocardial infarction, stroke and blood pressure, but its association with atherosclerosis is not clear. This meta-analysis was aimed at assessing whether PM2.5 and PM10 have an effect on subclinical atherosclerosis measured by carotid intima-media thickness (CIMT). Methods: Pubmed, Ovid Medline, Embase and NICK between 1948 and 31 March 2015 were searched by combining the keywords about exposure to the outcome related words. The random-effects model was applied in computing the change of CIMT and their corresponding 95% confidence interval (95% CI). The effect of potential confounding factors was assessed by stratified analysis and the impact of traffic proximity was also estimated. Results: Among 56 identified studies, 11 articles satisfied the inclusion criteria. In overall analysis increments of 10 μg/m3 in PM2.5 and PM10 were associated with an increase of CIMT (16.79 μm; 95% CI, 4.95–28.63 μm and 4.13 μm; 95% CI, −5.79–14.04 μm, respectively). Results shown in subgroup analysis had reference value for comparing with those of the overall analysis. The impact of traffic proximity on CIMT was uncertain. Conclusions: Exposure to PM2.5 had a significant association with CIMT and for women the effect may be more obvious

The mass-metallicity relation of Lyman-break analogues and its dependence on galaxy properties

We investigate the mass-metallicity relation and its dependence on galaxy physical properties with a sample of 703 Lyman-break analogues (LBAs) in local Universe, which have similar properties to high redshift star-forming galaxies. The sample is selected according to \ha luminosity, L(\ha)>10^{41.8}\,{\rm erg\,s^{-1}}, and surface brightness, I(\ha)>10^{40.5}\,{\rm erg\,s^{-1}\,kpc^{-2}}, criteria. The mass-metallicity relation of LBAs harmoniously agrees with that of star-forming galaxies at $z \sim$ 1.4-1.7 in stellar mass range of $10^{8.5}M_{\odot}<M_{*}<10^{11}M_{\odot}$. The relation between stellar mass, metallicity and star formation rate of our sample is roughly consistent with the local fundamental metallicity relation. We find that the mass-metallicity relation shows a strong correlation with the 4000\AA\, break; galaxies with higher 4000\AA\, break typically have higher metallicity at a fixed mass, by 0.06 dex in average. This trend is independent of the methodology of metallicity. We also use the metallicity estimated by $T_{\rm e}$-method to confirm it. The scatter in mass-metallicity relation can be reduced from 0.091 to 0.077 dex by a three-dimensional relation between stellar mass, metallicity and 4000\AA\, break. The reduction of scatter in mass-metallicity relation suggests that the galaxy stellar age plays an important role as the second parameter in the mass-metallicity relation of LBAs.Comment: 10 pages,8 figure

Quantitative Analysis of Heroin and its Metabolites in vivo

This study investigated heroin and its metabolites in vivo in the rat by using a high-performance liquid chromatography-tandem mass spectrometry (GC-MS) method

Decreasing erucic acid level by RNAi-mediated silencing of fatty acid elongase 1 (BnFAE1.1) in rapeseeds (Brassica napus L.)

The β-ketoacyl CoA synthase encoded by fatty acid elongase 1 gene (BnFAE1.1) is a rate-limiting enzyme regulating biosynthesis of erucic acid in rapeseeds (Brassica napus). To develop low level of erucic acid in rapeseeds by intron-spliced hairpin RNA, an inverted repeat unit of a partial BnFAE1.1 gene interrupted by a spliceable intron was cloned into pCAMBIA3301, and a seed-specific (Napin) promoter was used to control the transcription of the transgene. Four transgenic plants harboring a single copy of transgene were generated. Expression of endogenous BnFAE1.1 gene in developing T3 seeds was significantly reduced. In mature T3 seeds, erucic acid was decreased by 60.8 to 99.1% compared with wild type seeds, and accounted for 0.36 to 15.56% of total fatty acids. The level of eicosenoic acid was also greatly decreased. Furthermore, it resulted in a significant increase in the level of oleic acid, but total fatty acid content in T3 seeds was the same with that in wild type seeds. In conclusion, the expression of endogenous BnFAE1.1 was efficiently silenced by the designed RNAi silencer, causing a significant down-regulation in the level of erucic acid. Therefore, the RNAi-mediated post-transcriptional silencing of FAE1 gene to reduce oleic acid in rapeseeds was an efficient method to breed some new B. napus lines.Key words: Brassica napus L., fatty acid elongase, intron-spliced hairpin RNA, down-regulation, erucic acid

Theory of quantum energy transfer in spin chains: From superexchange to ballistic motion

Quantum energy transfer in a chain of two-level (spin) units, connected at its ends to two thermal reservoirs, is analyzed in two limits: (i) In the off-resonance regime, when the characteristic subsystem excitation energy gaps are larger than the reservoirs frequencies, or the baths temperatures are low. (ii) In the resonance regime, when the chain excitation gaps match populated bath modes. In the latter case the model is studied using a master equation approach, showing that the dynamics is ballistic for the particular chain model explored. In the former case we analytically study the system dynamics utilizing the recently developed Energy-Transfer Born-Oppenheimer formalism [Phys. Rev. E {\bf 83}, 051114 (2011)], demonstrating that energy transfers across the chain in a superexchange (bridge assisted tunneling) mechanism, with the energy current decreasing exponentially with distance. This behavior is insensitive to the chain details. Since at low temperatures the excitation spectrum of molecular systems can be truncated to resemble a spin chain model, we argue that the superexchange behavior obtained here should be observed in widespread systems satisfying the off-resonance condition