Anoectochilus roxburghii is a wild edible species and has been traditionally used for a wide range of diseases in many countries. Our research aims to find the optimal light-emitting diode (LED) lighting conditions to improve the growth and development of A. roxburghii seedling at the acclimation stage. Two-month-old explants were cultured under the various lighting conditions including red (R), blue (B), BR (one blue: four red), BRW151 (one blue: five red: one white), BRW142 (one blue: four red: two white), and fluorescent lamp (FL). The results showed that the lighting conditions not only affect the growth and morphology of plants but also the accumulation of total flavonoids. Single wavelengths (B or R LED) inhibited the growth and secondary biosynthesis of A. roxburghii, while the BR LED showed an enhancement in both growth and biomass accumulation. A. roxburghii plants were grown under BR LED light has average plant height (7.18 cm), stem diameter (17.6mm), number of leaves (5.78 leaves/tree), leaf area (4.67 cm2), fresh weight (0.459 g/tree), dry matter percentages (11.69%), and total flavonoid (1.811 mg/g FW) is considered to be superior to FL lamps and other LEDs in the experiment. This indicates that both blue and red wavelengths are required for the normal growth of A. roxburghii. To learn more about how light affects flavonoid biosynthesis, we evaluated the expression of genes involved in this process (pal, chs, chi, and fls) and found that BR LED light enhances the expression level of chi and fls genes compared to fluorescent lamps (1.18 and 1.21 times, respectively), leading to an increase in the flavonoid content of plant. Therefore, applying BR LED during in vitro propagation of A. roxburghii could be a feasible way to improve the medicinal value of this plant.
Three new pregnane glycosides, drevoluosides O-Q (1-3) along with five known volubiloside C (4), dreageoside A11 (5), 17β-marsdenin (6), stavaroside H (7), and hoyacarnoside G (8) were isolated from the methanol extract of the Dregea volubilis leaves. Their structures were elucidated by chemical and spectroscopic methods. Compounds 6-8 showed significant anti α-glucosidase activity with the inhibitory percentages ranging from 32.6 to 47.1 % at the concentration of 200 μM. Compound 3 showed significant inhibitory α-amylase activity with IC 50 value of 51.3 ± 2.1 μM.
Twenty road dust samples were collected from Ha Long and Cam Pha cities in Quang Ninh province for analysis of polycyclic aromatic hydrocarbons (PAHs) on the USEPA priority pollutant list. Total concentrations of sixteen PAHs in road dust samples of Ha Long and Cam Pha ranged from 232 - 593 ng/g d.w (average: 399 ng/g d.w) and 297 - 1624 ng/g d.w (average: 780 ng/g d.w), respectively. Proportitions of invididiuals were decreased in the order Phe (21% ± 13%) > Pyr (12% ± 6%) > Nap~Fluth (11% ± 6%) > BbF (10% ± 8%), suggesting the similar composition of analyzed PAHs in road dust at two cities. Based on the common diagnostic ratios for the identification of PAHs emission sources, the Fluth/(Fluth+Pyr) ratio (average: 0.43, range: 0.29-0.60), the BaA/(BaA+Chr) ratio (average: 0.30, range: 0.08-0.38), the IcdP/(IcdP+BghiP) ratio (average: 0.30, range: 0.22-0.46) and the BaP/BghiP ratio (average: 0.47 < 0.9) indicated that emissions from traffic activities may be the important sources of PAHs in Quang Ninh.
Analytical researches on a potential performance of multipath multiple-input multiple-output (MIMO) systems inspire the development of new technologies that decompose a MIMO channel into independent sub-channels on the condition of constrained transmit power. Moreover, in current studies of inter-symbol interference (ISI) MIMO systems, there is an assumption that channel state information (CSI) at receivers and/or transmitters is perfect. In this paper, we propose a hybrid design of precoding and equalization schemes based on the unweighted minimum mean square error criterion that not only eliminates the ISI but also improves the system performance. Additionally, the impact of imperfect channel knowledge at receivers on the system performance of MIMO ISI system is investigated. The simulation result shown that the proposed hybrid design of precoding and equalization with shared redundancy outperforms the conventional method in all considered scenarios. Furthermore, the proposed and the conventional schemes are extremely sensitive to the CSI factor, the performance of these systems is quickly deteriorated when the accuracy of channel estimation decreases.
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