1,472 research outputs found

    Dihydrochalcone glycosides from Oxytropis myriophylla

    Get PDF
    Chemical investigations of the 70% alcohol extract of Oxytropis myriophylla (Pall.) DC. (Leguminosae) have afforded the new natural product neohesperidin dihydrochalcone (1) and the known phloretin-4'-O-β-D-glucopyranoside (2), which was the first reported from the genus Oxytropis. This paper reports the isolation and full spectroscopic characterization of compounds 1 and 2 by NMR, UV, IR and MS data

    Using VBIM technique to identify novel carboplatin resistance gene in ovarian cancer

    Get PDF
    poster abstractOvarian cancer (OC) is the most lethal gynecology cancer in the world. Although carboplatin is one of the major drugs used to treat OC, resistance to carboplatin remains a major barrier to successful treatment. To date, the mechanisms of carboplatin resistance are still poorly understood. The purpose of this study is to use the novel validation-based insertional mutagenesis (VBIM) technique to identify carboplatin resistance gene in A2780 OC cells. A2780 cells were infected with VBIM virus to cause the overexpression of drug resistance genes, then were further selected under carboplatin treatment. Targeted gene was then identified by using VBIM specific primers. In a preliminary screen, we identified the novel carboplatin resistance gene 1 (NCR1). Overexpression of NCR1 increased carboplatin resistance in A2780 OC cells, while knocking it down with shRNA had the opposite effect. In an attempt to investigate the molecular mechanism that underlying NCR1-mediated carboplatin resistance, we found that NCR1 is a potential NF- B activator. In summary, we conclude that using a novel VBIM technique, we discovered a previously unknown carboplatin resistance gene NCR1, which may mediate drug resistance via NF-B signaling pathway. This study is of extreme importance by identifying a potential novel therapeutic target NCR1 in carboplatin resistance. Development of small chemical inhibitors targeting NCR1 could ultimately lead to novel therapeutic approach for ovarian cancer treatment

    Single spin asymmetry in πp\pi p Drell-Yan process

    Full text link
    We study the single spin asymmetries for the πpμ+μX\pi p^\uparrow\rightarrow\mu^+\mu^-X process. We consider the asymmetries contributed by the coupling of the Boer-Mulders function with the transversity distribution and the pretzelosity distribution, characterized by the sin(ϕ+ϕS)\sin(\phi+\phi_S) and sin(3ϕϕS)\sin(3\phi-\phi_S) azimuthal angular dependence, respectively. We estimate the magnitude of these asymmetries at COMPASS by using proper weighting functions. We find that the sin(ϕ+ϕS)\sin(\phi+\phi_S) asymmetry is of the size of a few percent and can be measured through the experiment. The sin(3ϕϕS)\sin(3\phi-\phi_S) asymmetry is smaller than the sin(ϕ+ϕS)\sin(\phi+\phi_S) asymmetry. After a cut on qTq_T, we succeed in enhancing the asymmetry.Comment: 11 pages, 2 figures, final version to appear in PL

    SAHARA: A Simplified AtmospHeric Correction AlgoRithm for Chinese gAofen Data: 1. Aerosol Algorithm.

    Get PDF
    The recently launched Chinese GaoFen-4 (GF4) satellite provides valuable information to obtain geophysical parameters describing conditions in the atmosphere and at the Earth’s surface. The surface reflectance is an important parameter for the estimation of other remote sensing parameters linked to the eco-environment, atmosphere environment and energy balance. One of the key issues to achieve atmospheric corrected surface reflectance is to precisely retrieve the aerosol optical properties, especially Aerosol Optical Depth (AOD). The retrieval of AOD and corresponding atmospheric correction procedure normally use the full radiative transfer calculation or Look-Up-Table (LUT) methods, which is very time-consuming. In this paper, a Simplified AtmospHeric correction AlgoRithm for gAofen data (SAHARA) is presented for the retrieval of AOD and corresponding atmospheric correction procedure. This paper is the first part of the algorithm, which describes the aerosol retrieval algorithm. In order to achieve high-accuracy analytical form for both LUT and surface parameterization, the MODIS Dark-Target (DT) aerosol types and Deep Blue (DB) similar surface parameterization have been proposed for GF4 data. Limited Gaofen observations (i.e., all that were available) have been tested and validated. The retrieval results agree quite well with MODIS Collection 6.0 aerosol product, with a correlation coefficient of R2 = 0.72. The comparison between GF4 derived AOD and Aerosol Robotic Network (AERONET) observations has a correlation coefficient of R2 = 0.86. The algorithm, after comprehensive validation, can be used as an operational running algorithm for creating aerosol product from the Chinese GF4 satellite.N/

    Quality assurance plan for China collection 2.0 aerosol datasets

    Get PDF
    The inversion of atmospheric aerosol optical depth (AOD) using satellite data has always been a challenge topic in atmospheric research. In order to solve the aerosol retrieval problem over bright land surface, the Synergetic Retrieval of Aerosol Properties (SRAP) algorithm has been developed based on the synergetic using of the MODIS data of TERRA and AQUA satellites [1, 2]. In this paper we describe, in details, the quality assessment or quality assurance (QA) plan for AOD products derived using the SRAP algorithm. The pixel-based QA plan is to give a QA flag to every step of the process in the AOD retrieval. The quality assessment procedures include three common aspects: 1) input data resource flags, 2) retrieval processing flags, 3) product quality flags [3]. Besides, all AOD products are assigned a QA ‘confidence’ flag (QAC) that represents the aggregation of all the individual QA flags. This QAC value ranges from 3 to 0, with QA = 3 indicating the retrievals of highest confidence and QA = 2/QA = 1 progressively lower confidence [4], and 0 means ‘bad’ quality. These QA (QAC) flags indicate how the particular retrieval process should be considered. It is also used as a filter for expected quantitative value of the retrieval, or to provide weighting for aggregating/averaging computations [5]. All of the QA flags are stored as a “bit flag” scientific dataset array in which QA flags of each step are stored in particular bit positions

    An atmospheric correction algorithm for FY3/MERSI data over land in China

    Get PDF
    Feng-Yun (FY-3) is the second generation of the Chinese Polar Orbiting Meteorological Satellites with global, three-dimensional, quantitative, and multispectral capabilities. Medium Resolution Spectral Imager (MERSI) has 20 channels onboard the FY-3A and FY-3B satellites, including five channels (four VIS and one thermal IR) with a spatial resolution of 250m. The top of the atmosphere signal are necessary to be radiometrically calibrated and corrected for atmospheric effects based on surface reflectance, especially in land surface remote sensing and applications. This paper presents an atmospheric correction algorithm for FY3/MERSI data over land in China, taking into account the directional properties of the observed surface by a kernel-based Bi-directional Reflectance Distribution Function (BRDF) model. The comparison with MODGA and ASD reflectance showed that there is a good agreement. Therefore, FY3/MERSI can serve a reliable and new data source for quantifying global environment change

    Post calibration of channel 1 of NOAA-14 AVHRR: Implications on aerosol optical depth retrieval

    Get PDF
    In order to produce long-term aerosol optical depth (AOD) dataset over land from the Advanced Very High Resolution Radiometer (AVHRR), AVHRR data quality in terms of radiometric calibration must be maintained. A vicarious calibration method have been developed by incorporating well calibrated Sea-Viewing Wide Field-of-View Sensor (SeaWiFS) radiance data over several pseudo-invariant targets to inter-calibrate the channel 1 of AVHRR based on Bidirectional Reflectance Distribution Functions (BRDFs) and spectral band adjustment factor (SBAF) models for different targets. Comparison of our calibration coefficients with those of Pathfinder Atmospheres Extended (PATMOS-x) indicate the calibration accuracy to be within 2.5%. The operational L1B and recalibrated AVHRR radiance are applied to derive AOD maps over East America (dark surface) and West Africa (bright surface) using the land aerosol and bidirectional reflectance inversion by times series technique (LABITS) algorithm. Preliminary comparisons show that significant difference in the retrieved AOD from the two different calibration is expected, while the spatial distribution of AOD difference is complicated due to different surface brightness and deficiencies of numeric solutions

    Effect of 3,3′-Biisofraxidin on Apoptosis of Human Gastric Cancer BGC-823 Cells

    Get PDF
    Purpose: To study the effect of 3,3′-biisofraxidin from Sarcandrae Herba on the proliferation of BGC- 823 cells and the possible mechanisms.Methods: Cell Counting Kit-8 (CCK-8), flow cytometry, Western blot and xenograft assays were used to determine the effects of 3,3′-biisofraxidin on the proliferation, apoptosis, apoptotic proteins and xenograft of BGC-823 cells.Results: 3,3′-Biisofraxidin significantly (p < 0.01) inhibited the proliferation of BGC-823 cells (concentrations: 10 - 40 μM; cell viability: 30.45 - 76.68 % in CCK-8 assay) with half maximal inhibitory concentration (IC50) value of 20.35 μM and induced the apoptosis of BGC-823 cells (concentrations: 10, 20 and 40 μM; apoptotic cells: 11.92, 20.10 and 33.64 % in flow cytometry assay), compared with the control (cell viability: 99.73 %; apoptotic cells: 5.18 %). 3,3′-Biisofraxidin (10, 20 and 40 μM in vitro; 40 mg/kg in vivo) significantly (p < 0.05 or 0.01) down-regulated the expressions of anti-apoptotic proteins (Bcl-2, Bcl-xl and Survivin) and up-regulated the expressions of pro-apoptotic proteins (Smac, caspase-3, caspase-7 and caspase-9), compared with the control. Moreover, the release of cytochrome c from the mitochondria to the cytoplasm was significantly (p < 0.01) promoted in vitro, compared with the control. 3,3′-Biisofraxidin (40 mg/kg) significantly (p < 0.05 or 0.01) inhibited the growth of tumor in xenograft assay, compared with the control.Conclusion: 3,3′-Biisofraxidin significantly induces the apoptosis of BGC-823 cells in vitro and in vivo through the mitochondria-mediated apoptotic pathway, and therefore has a potential to be developed into an anti-gastric cancer drug.Keywords: Sarcandrae Herba, Gastric cancer, 3,3′-Biisofraxidin, Mitochondria-mediated apoptotsis, Cell Counting Kit-8, Xenograf

    Log-Poisson Non-Gaussianity of Lyα\alpha Transmitted Flux Fluctuations at High Redshift

    Full text link
    We investigate the non-Gaussian features of the IGM at redshift z56z\sim 5 - 6 using Lyα\alpha transmitted flux of quasar absorption spectra and cosmological hydrodynamic simulation of the concordance Λ\LambdaCDM universe. We show that the neutral hydrogen mass density field and Lyα\alpha transmitted flux fluctuations possess all the non-Gaussian features predicted by the log-Poisson hierarchy, which depends only on two dimensionless parameters β\beta and γ\gamma, describing, respectively, the intermittence and singularity of the random fields. We find that the non-Gaussianity of the Lyα\alpha transmitted flux of quasars from z=4.9z=4.9 to z=6.3z=6.3 can be well reconstructed by the hydrodynamical simulation samples. Although the Gunn-Peterson optical depth and its variance underwent a significant evolution in the redshift range of 565 - 6, the intermittency measured by β\beta is almost redshift-independent in this range. More interesting, the intermittency of quasar's absorption spectra on physical scales 0.110.1-1 h1^{-1}Mpc in redshift 565 - 6 are found to be about the same as that on physical scales 1101-10 h1^{-1}Mpc at redshifts 242 - 4. Considering the Jeans length is less than 0.1 h1^{-1}Mpc at z5z\sim 5, and 11 h1^{-1}Mpc at z2z\sim 2, these results imply that the nonlinear evolution in high and low redshifts will lead the cosmic baryon fluid to a state similar to fully developed turbulence. The log-Poisson high order behavior of current high redshift data of quasar's spectrum can be explained by uniform UV background in the redshift range considered. We also studied the log-Poisson non-Gaussianity by considering inhomogeneous background. With several simplified models of inhomogeneous background, we found the effect of the inhomogeneous background on the log-Poisson non-Gaussianity is not larger than 1-sigma.Comment: 12 pages 10 figures, accepted by MNRA
    corecore