267 research outputs found

    Quality evaluation of cortex berberidis from different geographical origins by simultaneous high performance liquid chromatography combined with statistical methods

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    Purpose: To develop an effective method for evaluating the quality of Cortex berberidis from different geographical origins.Methods: A simple, precise and accurate high performance liquid chromatography (HPLC) method was first developed for simultaneous quantification of four active alkaloids (magnoflorine, jatrorrhizine, palmatine, and berberine) in Cortex berberidis obtained from Qinghai, Tibet and Sichuan Provinces of China. Method validation was performed in terms of precision, repeatability, stability, accuracy, and linearity. Besides, partial least squares discriminant analysis (PLS-DA) and one-way analysis of variance (ANOVA) were applied to study the quality variations of Cortex berberidis from various geographical origins.Results: The proposed HPLC method showed good linearity, precision, repeatability, and accuracy. The four alkaloids were detected in all samples of Cortex berberidis. Among them, magnoflorine (36.46 - 87.30 mg/g) consistently showed the highest amounts in all the samples, followed by berberine (16.00 - 37.50 mg/g). The content varied in the range of 0.66 - 4.57 mg/g for palmatine and 1.53 - 16.26 mg/g for jatrorrhizine, respectively. The total content of the four alkaloids ranged from 67.62 to 114.79 mg/g. Moreover, the results obtained by the PLS-DA and ANOVA showed that magnoflorine level and the total content of these four alkaloids in Qinghai and Tibet samples were significantly higher (p < 0.01) than those in Sichuan samples.Conclusion: Quantification of multi-ingredients by HPLC combined with statistical methods provide an effective approach for achieving origin discrimination and quality evaluation of Cortex berberidis. The quality of Cortex berberidis closely correlates to the geographical origin of the samples, with Cortex berberidis samples from Qinghai and Tibet exhibiting superior qualities to those from Sichuan.Keywords: Tibetan medicine, Cortex berberidis, Origin discrimination, Quality evaluation, Magnoflorine, Palmatine, Berberine, Jatrorrhizin

    SUMOylation of Grb2 enhances the ERK activity by increasing its binding with Sos1

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    BACKGROUND: Grb2 (Growth factor receptor-bound protein 2) is a key adaptor protein in maintaining the ERK activity via linking Sos1 (Son of sevenless homolog 1) or other proteins to activated RTKs, such as EGFR. Currently, little knowledge is available concerning the post-translational modification (PTM) of Grb2 except for its phosphorylation. Since emerging evidences have highlighted the importance of SUMOylation (Small ubiquitin-related modifier), a reversible PTM, in modulating protein functions, we wondered if Grb2 could be SUMOylated and thereby influences its functions especially involved in the Ras/MEK/ERK pathway. METHODS: SUMOylation of Grb2 was analyzed with the in vivo SUMOylation assay using the Ni(2+)-NTA affinity pulldown and the in vitro E.coli-based SUMOylation assay. To test the ERK activity and cell transformation, the murine fibroblast cell line NIH/3T3 and the murine colon cancer cell line CMT-93 were used for the experiments including Grb2 knockdown, ectopic re-expression, cell transformation and migration. Immunoprecipitation (IP) was employed for seeking proteins that interact with SUMO modified Grb2. Xenograft tumor model in mice was conducted to verify that Grb2 SUMOylation regulated tumorigenesis in vivo. RESULTS: Grb2 can be SUMOylated by SUMO1 at lysine 56 (K(56)), which is located in the linker region between the N-terminal SH3 domain and the SH2 domain. Knockdown of Grb2 reduced the ERK activity and suppressed cell motility and tumorigenesis in vitro and in vivo, which were all rescued by stable ectopic re-expression of wild-type Grb2 but not the mutant Grb2(K56R). Furthermore, Grb2 SUMOylation at K(56) increased the formation of Grb2-Sos1 complex, which sequentially leads to the activation of Ras/MEK/MAPK pathway. CONCLUSIONS: Our results provide evidences that Grb2 is SUMOylated in vivo and this modification enhances ERK activities via increasing the formation of Grb2-Sos1 complex, and may consequently promote cell motility, transformation and tumorigenesis

    Tolerancija imobiliziranih stanica kvasca prema ionskim tekućinama na bazi imidazola

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    Ionic liquids (ILs) are considered as another ’green solvent’, after the supercritical carbon dioxide. They are a promising reaction medium for biocatalysis process. The tolerance of active cells in hydrophobic imidazolium-based ILs (1-R-3-methylimidazolium hexafluorophosphate, [RMim][PF6]) has been studied in this work. Calcium-alginate-entrapped baker’s yeast has been chosen as the model of living cells. The results show that this kind of ILs possess a certain degree of biocompatibility. The tolerance of yeast cells to the ILs decreases with the increase of the R chain length of these ILs. The experiment indicated that 1-butyl-3-methylimidazolium hexafluorophosphate ([BMim][PF6]) possessed excellent biocompatibility compared to the other imidazolium-based ILs. The moisture content in the ILs was the key factor that affected the tolerance. The activity retention of yeast cells pretreated with [BMim][PF6] saturated with water and aqueous [BMim][PF6] biphasic system was about 70 %, but it was only 50 % with the anhydrous [BMim][PF6]. Although the yeast cells were pretreated with [BMim][PF6] for 24 h, the activity retention was up to 45 %. The yeast cells had around 50 % activity after being pretreated 4 times with [BMim][PF6]. This shows that the water immiscible ILs possess good biocompatibility, and they are suitable for application as the reaction medium catalyzed by living cells.Ionske tekućine, a i superkritični ugljikov dioksid, smatraju se ekoloĆĄki prihvatljivim otapalima. Mogu se upotrijebiti kao reagens u biokatalitičkim reakcijama. U ovom je radu ispitana tolerancija aktivnih stanica kvasca prema hidrofobnim ionskim tekućinama na bazi imidazola (1-R-3-metilimidazolijev heksafluorofosfat, [RMim][PF6]). Kao model ĆŸivih stanica upotrijebljene su stanice pekarskog kvasca imobilizirane u kalcijevom alginatu. Rezultati su pokazali da ispitane ionske tekućine imaju određeni stupanj biokompatibilnosti. Tolerancija stanica kvasca prema ispitanim tekućinama smanjivala se s porastom duljine alkilnog lanca (R). Utvrđeno je da 1-butil-3-metilimidazolijev heksafluorofosfat ([BMim][PF6]), u usporedbi s drugim ionskim tekućinama na bazi imidazola, ima odličnu biokompatibilnost. Pri tome vaĆŸnu ulogu ima udio vode u ionskoj tekućini. Stanice kvasca obrađene s [BMim][PF6] zasićenim vodom ili s vodenim dvofaznim sustavom [BMim][PF6] zadrĆŸale su i do 70 % svoje aktivnosti, a one tretirane s bezvodnim [BMim][PF6] imale su samo 50 %-tnu aktivnost. Stanice su kvasca čak i nakon 24-satne obrade s [BMim][PF6] zadrĆŸale do 45 % aktivnosti. Nakon 4 tretmana s [BMim][PF6] stanice su i dalje zadrĆŸale aktivnost od otprilike 50 %. To potvrđuje da ionske tekućine koje se mijeĆĄaju s vodom imaju dobru biokompatibilnost i da se mogu primijeniti kao reagens u reakcijama kataliziranima s pomoću ĆŸivih stanica kvasca

    Measurement of CP asymmetries and branching fraction ratios of B− decays to two charm mesons

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    The CPCP asymmetries of seven B−B^- decays to two charm mesons are measured using data corresponding to an integrated luminosity of 9fb−19\text{fb}^{-1} of proton-proton collisions collected by the LHCb experiment. Decays involving a D∗0D^{*0} or Ds∗−D^{*-}_s meson are analysed by reconstructing only the D0D^0 or Ds−D^-_s decay products. This paper presents the first measurement of ACP(B−→Ds∗−D0)\mathcal{A}^{CP}(B^- \rightarrow D^{*-}_s D^0) and ACP(B−→Ds−D∗0)\mathcal{A}^{CP}(B^- \rightarrow D^{-}_s D^{*0}), and the most precise measurement of the other five CPCP asymmetries. There is no evidence of CPCP violation in any of the analysed decays. Additionally, two ratios between branching fractions of selected decays are measured.The CP asymmetries of seven B−^{−} decays to two charm mesons are measured using data corresponding to an integrated luminosity of 9 fb−1^{−1} of proton-proton collisions collected by the LHCb experiment. Decays involving a D∗0^{*0} or Ds∗− {D}_s^{\ast -} meson are analysed by reconstructing only the D0^{0} or Ds− {D}_s^{-} decay products. This paper presents the first measurement of ACP \mathcal{A} ^{CP}(B−^{−}→Ds∗− {D}_s^{\ast -} D0^{0}) and ACP \mathcal{A} ^{CP}(B−^{−}→Ds− {D}_s^{-} D∗0^{∗0}), and the most precise measurement of the other five CP asymmetries. There is no evidence of CP violation in any of the analysed decays. Additionally, two ratios between branching fractions of selected decays are measured.[graphic not available: see fulltext]The CPCP asymmetries of seven B−B^- decays to two charm mesons are measured using data corresponding to an integrated luminosity of 9 fb−19\text{ fb}^{-1} of proton-proton collisions collected by the LHCb experiment. Decays involving a D∗0D^{*0} or Ds∗−D^{*-}_s meson are analysed by reconstructing only the D0D^0 or Ds−D^-_s decay products. This paper presents the first measurement of ACP(B−→Ds∗−D0)\mathcal{A}^{CP}(B^- \rightarrow D^{*-}_s D^0) and ACP(B−→Ds−D∗0)\mathcal{A}^{CP}(B^- \rightarrow D^{-}_s D^{*0}), and the most precise measurement of the other five CPCP asymmetries. There is no evidence of CPCP violation in any of the analysed decays. Additionally, two ratios between branching fractions of selected decays are measured

    Design of Intelligent Solar PV Power Generation Forecasting Mechanism Combined with Weather Information under Lack of Real-Time Power Generation Data

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    In order to reduce the cost of data transmission, the meter data management system (MDMS) of the power operator usually delays time to obtain the power generation information of a solar photovoltaic (PV) power generation system. Although this approach solves the problem of data transmission cost, it brings more challenges to the solar PV power generation forecast. Because power operators usually need real-time solar PV power generation as a basis for the power dispatch, but considering the cost of communication, they cannot always provide corresponding historical power generation data in real time. In this study, an intelligent solar PV power generation forecasting mechanism combined with weather information is designed to cope with the issue of the absence of real-time power generation data. Firstly, the Pearson correlation coefficient analysis is used to find major factors with a high correlation in relation to solar PV power generation to reduce the computational burden of data fitting via a deep neural network (DNN). Then, the data preprocessing, including the standardization and the anti-standardization, is adopted for data-fitting or real-time solar PV power generation data to take as the input data of a long short-term memory neural network (LSTM). The salient features of the proposed DNN-LSTM model are: (1) only the information of present solar PV power generation is required to forecast the one at the next instant, and (2) an on-line learning mechanism is helpful to adjust the trained model to adapt different solar power plant or environmental conditions. In addition, the effectiveness of the trained model is verified by six actual solar power plants in Taiwan, and the superiority of the proposed DNN-LSTM model is compared with other forecasting models. Experimental verifications show that the proposed forecasting model can achieve a high accuracy of over 97%

    Band-Reweighed Gabor Kernel Embedding for Face Image Representation and Recognition

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    Multilayer Surface Albedo for Face Recognition With Reference Images in Bad Lighting Conditions

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    Preparation, Characterization, and Performance Evaluation of Petroleum Asphalt Modified with Bio-Asphalt Containing Furfural Residue and Waste Cooking Oil

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    The study aims to analyze the feasibility of proposing waste cooking oil and industrial waste furfural residue as raw materials to prepare bio-asphalt as partial substitutes for petroleum asphalt, so as to reduce the cost of pavement construction and decrease the consumption of non-renewable resources. In this study, 90# petroleum asphalt was partially substituted with the bio-asphalt in different proportions to prepare biomass-modified petroleum asphalt, the performance of which was first evaluated based on three indices: penetration, softening point, and ductility. Comparison of the crystal structures of the bio-asphalt and furfural residue were enabled by X-ray diffraction, and the blending mechanism and microscopic morphologies of the biomass-substituted asphalt mixtures were characterized by Fourier transform infrared spectroscopy and scanning electron microscopy. The results showed that the bio-asphalt was hydrophobic and exhibited excellent compatibility with 90# petroleum asphalt. The partial substitution of petroleum asphalt with bio-asphalt improved the low-temperature crack resistance of the asphalt by adversely affecting the high-temperature stability of the asphalt; however, when the bio-asphalt content was 8 wt.%, the performance parameters of the biomass-modified asphalt met the requirements of the 90# petroleum asphalt standard

    An Efficient Automatic Video Shot Size Annotation Scheme*

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    Abstract. This paper presents an efficient learning scheme for automatic annotation of video shot size. Instead of existing methods that applied in sports videos using domain knowledge, we are aiming at a general approach to deal with more video genres, by using a more general low- and mid- level feature set. Support Vector Machine (SVM) is adopted in the classification task, and an efficient co-training scheme is used to explore the information embedded in unlabeled data based on two complementary feature sets. Moreover, the subjectivity-consistent costs for different mis-classifications are introduced to make the final decisions by a cost minimization criterion. Experimental results indicate the effectiveness and efficiency of the proposed scheme for shot size annotation.
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