41 research outputs found

    Diversity-function relationships in natural, applied, and engineered microbial ecosystems

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    PREPARATION OF Au-LOADED TiO2 BY PHOTOCHEMICAL DEPOSITION AND OZONE PHOTOCATALYTIC DECOMPOSITION

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    In this paper, Au-loaded TiO2 (Au/TiO2) photocatalysts were prepared by photochemical deposition method and characterized by transmission electron microscopy, diffuse reflectance spectroscopy and X-ray photoelectron spectroscopy. The results indicated the metallic Au nanoparticles were deposited on the surface of TiO2 after the high-pressure mercury irradiation and regarded as an electronegative center. The photocatalytic decomposition of gaseous ozone was investigated on TiO2 and Au-loaded TiO2 at room temperature. Results indicated that the photocatalytic conversion of ozone can be improved by Au/TiO2 and photocatalytic activity increased with the increase of the photodeposition time. The photocatalytic removal rate of ozone remained above 96% on the surface of 1% Au/TiO2 with photodeposition for 120 min under black lamp irradiation for 20 h. Au cluster deposited on the surface of TiO2 functioned not only as the electron trap center but also as the adsorption site of O3 in photocatalytic reaction.Photochemical deposition, photocatalysis, Au/TiO2, photocatalytic decomposition, ozone

    EFFECT OF Au DEPOSITION ON PHOTOCATALYTIC ACTIVITY OF ZnO NANOPARTICLES FOR CO OXIDATION

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    In this paper, pure and Au-deposited ZnO nanoparticles with different Au content were prepared and characterized. The effect of Au content on the PL properties and photocatalytic activity of CO oxidation was mainly investigated. The results showed that Au deposition can greatly decrease the intensity of PL and enhance the photocatalytic activity of CO oxidation, which may be attributed to the increased amounts of O2−{\rm O}_{2}^{-} and the formation of O (or O-) on Au/ZnO surface.CO photocatalytic oxidation, Au/ZnO, photoluminescence (PL) spectra

    Impacts of Sedimentation and Diagenesis on Deeply Buried Reservoir Quality of a Rift Basin: A Case Study of Wenchang Formation in the Lufeng Depression, Pearl River Mouth Basin, China

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    The deeply buried reservoirs of Wenchang Formation in the Lufeng Depression, Pearl River Mouth Basin, display strong heterogeneity, and the major controls for the development of high-quality reservoirs remain unclear. To address these issues, we conducted a series of experiment analyses, including petrographic microscope, scanning electron microscopy, and X-ray diffraction, and analyzed the impacts of sedimentation and diagenesis on the quality of deeply buried reservoirs. The results demonstrate that the sandbodies of subaqueous distributary channel and mouth bar deposited in lowstand systems tract (LST) and highstand systems tract (HST), as compared to the beach-bar and subaqueous fan sandstones deposited in transgressive systems tract (TST), have coarser grain size, higher quartz content, and lower muddy matrix content, which induced stronger anti-compaction capability, higher preservation of intergranular pore spaces, and thus better reservoir qualities. The reservoir types developed in subaqueous distributary channel and mouth bar are mainly types I, II, and III with medium-low porosity and low-ultra low permeability, while beach-bar and subaqueous fan mainly developed type III reservoir with low-porosity and ultra-low permeability. The reservoirs developed in E2w of the study area have undergone strong compaction, intense dissolution, but weak cementation. The subaqueous distributary channel and mouth bar reservoirs in LST are adjacent to Ew4 source rock in spatial distribution, resulting in strong organic acid dissolution, and developed numerous dissolved pores. The charging of hydrocarbons before deep burial further inhibited the later compaction and cementation and protects the preservation of residual primary intergranular pores and secondary dissolved pores. The combination of these factors leads to the development of the abnormally high porosity and high-quality reservoirs in LST. The results of this study reveal the genetic mechanism of deep, high-quality reservoirs in the rift basin and guide the selection of high-quality reservoirs in the later stage

    Comparative Analysis of Theoretical, Observational, and Modeled Deformation of Ground Subsidence: The Case of the Alhada Pb-Zn Mine

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    In this study, the probability integral method, Synthetic Aperture Radar Interferometry (InSAR), and the Okada dislocation model were collaboratively used to analyze deformation in the Alhada Pb-Zn mine. The predicted deformation values of the subsidence centers in three subsidence areas were 107 mm, 120 mm, and 83 mm, respectively, as predicted using the probability integral method. The coherent scatterer InSAR technique was used to analyze the time-series deformation of the mining area, and the same subsidence center locations and similar deformation values were observed. The Okada dislocation model was used to invert the optimal parameters of the underground-mining ore body causing the surface subsidence, indicating that the surface subsidence is mainly caused by the mining of ore bodies in the 888 and 848 middle sections. We further simulated ground deformation using the multi-source Okada model. The results showed that the predicted and modeled deformations are highly correlated with the observed deformation. Through the analysis and comparison of the InSAR results, it was concluded that the three subsidence areas do not threaten the stability of the main buildings in the mining area. Using theoretical, observational, and modeling methods, the development and evolution of the subsidence area in mines can be established, which could provide basic data for subsidence control work and guarantee mine production safety

    PET Demonstrates Functional Recovery after Treatment by Danhong Injection in a Rat Model of Cerebral Ischemic-Reperfusion Injury

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    This study aimed to investigate neuroprotection of Danhong injection (DHI) in a rat model of cerebral ischemia using 18F-fluorodeoxyglucose positron emission tomography (18F-FDG-PET). Method. Rats were divided into 5 groups: sham group, ischemia-reperfusion untreated (IRU) group, DHI-1 group (DHI 1 mL/kg/d), DHI-2 group (DHI 2 mL/kg/d), and DHI-4 group (DHI 4 mL/kg/d). AII the treated groups were intraperitoneally injected with DHI daily for 14 days. The therapeutic effects in terms of cerebral infarct volume, neurological function, and cerebral glucose metabolism were evaluated. Expression of TNF-α and IL-1ÎČ was detected with enzyme-linked immunosorbent assay (ELISA). Levels of mature neuronal marker (NeuN), glial marker (GFAP), vascular density factor (vWF), and glucose transporter 1 (GLUT1) were assessed by immunohistochemistry. Results. Compared with the IRU group, rats treated with DHI showed dose dependent reductions in cerebral infarct volume and levels of proinflammatory cytokines, improvement of neurological function, and recovery of cerebral glucose metabolism. Meanwhile, the significantly increased numbers of neurons, gliocytes, and vessels and the recovery of glucose utilization were found in the peri-infarct region after DHI treatment using immunohistochemical analysis. Conclusion. This study demonstrated the metabolic recovery after DHI treatment by micro-PET imaging with 18F-FDG and the neuroprotective effects of DHI in a rat model of cerebral ischemic-reperfusion injury

    AU4S: A novel synthetic peptide to measure the activity of ATG4 in living cells

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    <div><p>ATG4 plays a key role in autophagy induction, but the methods for monitoring ATG4 activity in living cells are limited. Here we designed a novel fluorescent peptide named AU4S for noninvasive detection of ATG4 activity in living cells, which consists of the cell-penetrating peptide (CPP), ATG4-recognized sequence “GTFG,” and the fluorophore FITC. Additionally, an ATG4-resistant peptide AG4R was used as a control. CPP can help AU4S or AG4R to penetrate cell membrane efficiently. AU4S but not AG4R can be recognized and cleaved by ATG4, leading to the change of fluorescence intensity. Therefore, the difference between AU4S- and AG4R-measured fluorescence values in the same sample, defined as “F-D value,” can reflect ATG4 activity. By detecting the F-D values, we found that ATG4 activity paralleled LC3B-II levels in rapamycin-treated cells, but neither paralleled LC3B-II levels in starved cells nor presented a correlation with LC3B-II accumulation in WBCs from healthy donors or leukemia patients. However, when DTT was added to the system, ATG4 activity not only paralleled LC3B-II levels in starved cells in the presence or absence of autophagy inhibitors, but also presented a positive correlation with LC3B-II accumulation in WBCs from leukemia patients (<i>R<sup>2</sup></i> = 0.5288). In conclusion, this study provides a convenient, rapid, and quantitative method to monitor ATG4 activity in living cells, which may be beneficial to basic and clinical research on autophagy.</p></div
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