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Objective: This study aimed to investigate the protective effect of dihydromyricetin （DHM） and its derivatives on oxidative damage of hepatocytes. Methods: The hydrogen peroxide damage model of L02 cells was established. DHM derivatives with different lipophilicity were obtained by enzymatic acylation of DHM. The levels of reactive oxygen species （ROS）, lactate dehydrogenase （LDH）, malondialdehyde （MDA）, catalase （CAT）, superoxide dismutase （SOD）, glutathione peroxidase （GSH-PX）, and mitochondrial membrane potential and Caspase 3 were measured to evaluate the protective effect of DHM and its derivatives on damaged hepatocytes. Results: Except for 3-O-lauroyl-DHM, the level of reactive oxygen species （ROS） the release of lactate dehydrogenase （LDH） and the level of malondialdehyde （MDA） and Caspase 3 in damaged hepatocytes treated with other derivatives decreased significantly, while the levels of antioxidant enzymes and the mitochondrial membrane potential increased. Of which, 3-O-octanoyl-DHM showed the best protective effect. Conclusion: Dihydromyricetin derivatives with medium chain length have better liver protection effect.

BACKGROUND Total boron in geological samples is determined by inductively coupled plasma-optical emission spectroscopy (ICP-OES) with acid digestion. The key steps are preventing the loss of boron during the sample digestion stage and reducing matrix interference, spectral interference and memory effect during measurement. OBJECTIVES To establish a method for the determination of boron in geological samples by ICP-OES with low-pressure closed digestion. METHODS Using HF-HNO3-HClO4-H3PO4 to digest samples in a low-pressure closed sample tank, the dissolved boron element is fully complexed with a small amount of phosphoric acid to prevent the volatilization loss of boron. The standard curve was calibrated using the geological solid standard material with similar concentration of matrix and major components to effectively match and reduce the matrix interference of the sample. The operating software provided by the instrument was used to observe and analyze the interference of other elements near the spectral line and to determine the best position and width of background subtraction to reduce the spectral interference in the ICP-OES measurement. 10% Aqua regia was used as the rinsing liquid of the sample introduction system, which effectively reduced the memory effect during measurement. RESULTS When the dilution factor was 200, the detection limit (3SD) was 1.2μg/g, and the quantitative limit (10SD) was 4.0μg/g. The precision and accuracy were analyzed and verified by using the national first-class standard substances in rock, soil and river sediment, the relative standard deviations (n=11) were from 1.8% to 7.9%, and the relative errors were from -3.6% to 6.3%. Compared with the results of external tests, the relative error of boron content above the quantitative limit ranged from -9.3% to 12.5%. CONCLUSIONS The method is suitable for the accurate measurement of boron above 4.0μg/g in geological samples.

BACKGROUND The transition metals copper, cobalt, nickel, zinc, lead and the noble metal elements (the platinum family elements gold, and silver) are highly enriched in sulfide minerals, especially in magmatic sulfides. Sulfides commonly form large ore deposits of industrial significance, which makes sulfide minerals of great economic value. There are many kinds of sulfide ores, and the contents of Ag, Cu, Pb and Zn in different types of sulfide ores vary. Some sulfide ores cannot be decomposed completely by strong acid and therefore precipitation forms, resulting in large errors and low precision. OBJECTIVES Investigate different digestion conditions in order to decompose, dissolved sulfide ores containing pyrite, galena and chalcopyrite. METHODS The sulfide ores are reacted with hydrochloric acid to remove the sulfur, and then digested by HNO3-HF-HClO4. Newly prepared aqua regia is used to further dissolve metals. The contents of silver, copper, lead and zinc in sulfide ores are determined by Flame Atomic Absorption Spectrometry (FAAS) and Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES). RESULTS The results show that sulfide ores can be decomposed ideally using the proposed procedure, especially for sulfide ores with high contents of silver and lead. The contents of silver, copper, lead and zinc in sulfide ores can be determined accurately by both FAAS and ICP-OES with a relative error of two methods of less than ±2.32%. The measured values are the same with the relative standard deviation(RSD, n=12) less than 3.5%. The detection limit of the four elements is below 0.0090 μg/mL, lower than current published values. CONCLUSIONS This method can be used to obtain an ideal decomposition effect, especially for high content silver and lead sulfide ore samples.

In traditional plane near-field acoustic holography reconstruction process,regardless of wave number domain filter or regularization method,they cannot solve their own ill-posed problem,and thus cannot improve the reconstruction accuracy. Plane near-field acoustic holography based on Compressive Sampling,translates traditional solved particle velocity into solving sparse coefficient,by effective using of the particle velocity sparsity,avoiding the reconstruction process of ill-posed problem. Combined with plane near-field acoustic holography based on Tikhonov regularization method, we analyze the reconstruction accuracy of numerical simulation. The results show that, plane near-field acoustic holography based on Compressive Sampling has a good accuracy in reconstruction process,especially in the border region of reconstructive surface.Finally,this method can effectively identify the source of the noise of the refrigerator,to provide an effective basis for noise control.

Proton radiography is a widely used experimental method to diagnose the electric and magnetic (EM) fields in high-energy-density plasmas. In proton radiography, the probe protons are typically assumed to be deflected only by the EM fields, whereas the Coulomb scattering caused by the charged particles in the target plasmas is generally ignored. However, at high plasma densities, the presence of Coulomb scattering could reduce the proton flux perturbations recorded on the detector and influence the inversion of the EM fields from experiments. In this paper, a theoretical model is developed for the first time to describe the proton flux distribution on the detector when the EM field deflections and Coulomb scattering coexist in deflecting the probe proton trajectories. Our theory indicates that the Coulomb scattering could decrease the signal contrast of the probed EM fields, which is determined not only by the strengths of the EM field deflections and Coulomb scattering but also by the spatial gradient of the EM fields. Monte Carlo simulations are also conducted to validate our theoretical model. It would be helpful to interpret the proton radiography experiments quantitatively. [ABSTRACT FROM AUTHOR]

Eudicots exhibit diverse life forms and occupy a wide variety of habitats in the modern terrestrial ecosystems, and the diversification began during the Early Cretaceous; however, few Early Cretaceous fossils are preserved as multiorgan whole plants that can provide sufficient morphological characters for detailed phylogenetic assessment. Here, Fairlingtonia microgyna sp. nov. is reported from the upper Lower Cretaceous of Zhonggou Formation, Hanxia Section, Yumen City, western Gansu Province, Northwest China. The specimen is exceptionally preserved as multiorgan whole plant fossil with fibrous adventitious roots, simple and deeply dissected leaves, solitary and dehiscent capsular fruits attached to the creeping stems. As such, it was interpreted as a herbaceous eudicot. Phylogenetic analyses support a placement within the Papaveraceae, most likely in Papaveroideae, but there are obvious differences in morphological characteristics, which cannot confirm the systematic position within the Papaveraceae. Fossil records of Fairlingtonia from contemporaneous deposits (late Aptian to early Albian) in Northwest China and eastern North America provide direct evidence of the geographical radiation of Fairlingtonia on Laurasia. And the morphological characters of F. microgyna, including creeping leafy branches, fibrous adventitious roots, small and deeply dissected leaves as well as small capsular fruits with tiny seeds probably indicate that it was a colonizer of lake‐shore environments under wet and bright conditions and possessed fast‐growing and rapid propagation habitats, which allowed it to expand its geographic range with both sexual and asexual reproduction. [ABSTRACT FROM AUTHOR]

Purposes The typical street canyon-building of the city is researched in this work. Methods On the basis of field measurement and numerical simulation CFD(Computational Fluid Dynamics), the airflow pattern and pollutant distribution in street canyon and indoor the building with windows opening were investigated. Findings The results show that the opening of windows on the outer wall of building disturbs the surrounding air flow, which leads to the enhancements of the vortex flow in the street canyon, and the variation of local wind direction and wind speed in different heights. The turbulence intensity of the street-facing buildings on the leeward side is more obviously affected by the opening of the windows than that of the buildings on the windward side,1~4 floors are 20.6% higher than the case of unopened windows. The change of indoor pollutant concentration on each floor is roughly consistent with the outdoor street canyon pollutant distribution. The indoor pollutant concentration of leeward buildings is much higher than that of windward buildings. Concentrations of indoor pollutants in leeward buildings decrease with the increase of floors, the pollutants on floors 1~4 account for 43.7% of the total pollution. The indoor pollutant concentration of buildings on the windward side first decreases along the building height, but does not show a monotonous trend of decreasing floor by floor. The pollutant concentration value is the smallest near the middle floor of building, then increases under the combined action of window disturbance and street canyon circulation vortex. The whole solution of street canyon-window building overcomes the inconsistency between the inflow level setting of simulated street buildings and the actual working conditions, better solves the problems of complex vortex boundary setting and different window opening positions from floor to floor.