1,933 research outputs found

    Chromatographic determination of siphonodin content: A rapid and simple strategy for discriminating between Hemsleya omeiensis and other sources of Xuedan

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    Purpose: To develop a rapid and simple siphonodin content-based high performance liquid chromatography (HPLC) method to distinguish Hemsleya omeiensis from other sources of xuedan. Methods: Siphonodin was isolated from Hemsleya omeiensis and identified by x-ray crystallographic analysis. An optimized HPLC method was applied for the determination of siphonodin contents of H. omeiensis, H. dolichocarpa and H. gigantha. Results: Siphonodin was successfully separated by the optimized HPLC method in < 10 min, and the results of validation showed that the HPLC method was stable and very accurate for the quantification of siphonodin. The mean content of siphonodin in 10 batches of H. omeiensis was 3.78 mg/g, but the compound was not detectable in H. dolichocarpa and H. gigantha using the developed HPLC method. Conclusion: These results indicate that the developed HPLC method is suitable for distinguishing H. omeiensis from other sources of xuedan

    Fingerprint and multi-component quantitative analyses for quality evaluation of Rhizoma coptidis steamed with rice wine

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    Purpose: To establish a method for the simultaneous determination of multi-components of Rhizoma coptidis steamed with rice wine (RCRW), and to provide a reference for assessing its standard of quality. Method: Chromatographic separation was performed on a high performance liquid chromatography (HPLC) system to determine the characteristic fingerprint of RCRW. The mobile phase consisted of acetonitrile (A) and 0.1 % trifluoroacetic acid (B), with gradients of B as follows: 15 - 20 % from 0 – 30 min; 20 - 25 % from 30 - 50 min; 25 - 35 % for 50 - 60 min, and 35 % for 60 - 70 min. Results: In the multiple reaction monitoring mode, eight components of RCRW were isolated by HPLCphoto-diode array (PDA) method. A fingerprint of the RCRW was established and 8 peaks were calibrated. The method was further validated in terms of linearity (R2 > 0.9993), precision (relative standard deviation, RSD < 1.51 %); repeatability (RSD < 2.98 %) and stability (RSD < 1.93 %). Mean recovery rate ranged from 96.2 to 103.8 %, while RSD values ranged from 0.92 to 2.88 %. Conclusion: These results show that HPLC-PDA method is accurate and feasible, and that they provide a reference for further comprehensive and effective quality control of RCRW

    High-level expression and purification of soluble recombinant FGF21 protein by SUMO fusion in Escherichia coli

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    <p>Abstract</p> <p>Background</p> <p>Fibroblast growth factor 21 (FGF21) is a promising drug candidate to combat metabolic diseases. However, high-level expression and purification of recombinant FGF21 (rFGF21) in <it>Escherichia coli (E. coli) </it>is difficult because rFGF21 forms inclusion bodies in the bacteria making it difficult to purify and obtain high concentrations of bioactive rFGF21. To overcome this problem, we fused the <it>FGF21 </it>with <it>SUMO </it>(Small ubiquitin-related modifier) by polymerase chain reaction (PCR), and expressed the fused gene in <it>E. coli </it>BL21(DE3).</p> <p>Results</p> <p>By inducing with IPTG, SUMO-FGF21 was expressed at a high level. Its concentration reached 30% of total protein, and exceeded 95% of all soluble proteins. The fused protein was purified by DEAE sepharose FF and Ni-NTA affinity chromatography. Once cleaved by the SUMO protease, the purity of rFGF21 by high performance liquid chromatography (HPLC) was shown to be higher than 96% with low endotoxin level (<1.0 EU/ml). The results of <it>in vivo </it>animal experiments showed that rFGF21 produced by using this method, could decrease the concentration of plasma glucose in diabetic rats by streptozotocin (STZ) injection.</p> <p>Conclusions</p> <p>This study demonstrated that SUMO, when fused with FGF21, was able to promote its soluble expression of the latter in <it>E. coli</it>, making it more convenient to purify rFGF21 than previously. This may be a better method to produce rFGF21 for pharmaceutical research and development.</p

    Differences among fathers, mothers, and teachers in symptom assessment of ADHD patients

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    BackgroundThe Swanson Nolan, and Pelham scale version IV (SNAP-IV) is the most critical tool for ADHD screening and diagnosis, which has two scoring methods. ADHD requires symptom assessment in multiple scenarios, and parent and teacher reports are indispensable for diagnosing ADHD. But the differences of assessment results from fathers, mothers and teachers, and the consistency of results from different scoring methods are unknown. Therefore, we carried out this study to understand the differences in the scores of fathers, mothers and teachers using SNAP-IV for children with ADHD and to explore the differences in scoring results under different scoring methods.MethodsThe SNAP-IV scale and Demographics Questionnaire and Familiarity Index were used to survey fathers, mothers and head teachers. Measurement data are expressed as the mean ± standard deviation (x ± s). The enumeration data were described by frequency and percentage. ANOVA was used to compare group differences in mothers’, fathers’, and teachers’ mean SNAP-IV scores. The Bonferroni method was used for post hoc multiple comparison tests. Cochran’s Q test was used to compare the differences in the abnormal rate of SNAP-IV score results of mothers, fathers and teachers. Dunn’s test was used for post hoc multiple comparison tests.ResultsThere were differences in scores among the three groups, and the differences showed inconsistent trends across the different subscales. Differences between groups were calculated again with familiarity as a control variable. The results showed the familiarity of parents and teachers with the patients did not affect the differences in their scores. The evaluation results were different under two assessment methods.ConclusionResults concluded that fathers did not appear to be an appropriate candidate for evaluation. When using the SNAP-V for assessment, it should be comprehensively considered from both the scorer and symptom dimensions

    Affection Driven Neural Networks for Sentiment Analysis

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    Deep neural network models have played a critical role in sentiment analysis with promising results in the recent decade. One of the essential challenges, however, is how external sentiment knowledge can be effectively utilized. In this work, we propose a novel affection-driven approach to incorporating affective knowledge into neural network models. The affective knowledge is obtained in the form of a lexicon under the Affect Control Theory (ACT), which is represented by vectors of three-dimensional attributes in Evaluation, Potency, and Activity (EPA). The EPA vectors are mapped to an affective influence value and then integrated into Long Short-term Memory (LSTM) models to highlight affective terms. Experimental results show a consistent improvement of our approach over conventional LSTM models by 1.0% to 1.5% in accuracy on three large benchmark datasets. Evaluations across a variety of algorithms have also proven the effectiveness of leveraging affective terms for deep model enhancement

    Bis[μ-N′-(adamantan-1-ylcarbon­yl)-2-oxidobenzohydrazidato(3−)]tetra­pyridine­trinickel(II) dimethyl­formamide monosolvate monohydrate

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    In the title trinuclear NiII compound, [Ni3(C18H19N2O3)2(C5H5N)4]·C3H7NO·H2O, three NiII cations are bridged by two N′-(adamantan-1-ylcarbon­yl)-2-oxidobenzohydrazidate trianions. The central NiII cation has a distorted octa­hedral N4O2 coordination environment where a reverse torsion occurs between the two bridging ligands, whereas the two NiII cations on the sides each adopt an N2O2 square-planar coordination. Weak intra­molecular C—H⋯O and C—H⋯N inter­actions help to stabilize the mol­ecular structure. In the crystal, the lattice water mol­ecule links with the NiII complex and dimethyl­formamide solvent mol­ecule via O—H⋯O hydrogen bonding

    Integration of the 3DOM Al/Co3O4 nanothermite film with a semiconductor bridge to realize a high-output micro-energetic igniter

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    Microigniters play an important role for the reliable initiation of micro explosive devices. However, the microigniter is still limited by the low out-put energy to realize high reliability and safety. Integration of energetic materials with microigniters is an effective method to enhance the ignition ability. In this work, a Al/Co3O4 nanothermite film with a three-dimensionally ordered macroporous structure was prepared by the deposition of nanoscale Al layers using magnetron sputtering on Co3O4 skeletons that are synthesized using an inverse template method. Both the uniform structure and nanoscale contact between the Al layers and the Co3O4 skeletons lead to an excellent exothermicity. In order to investigate the ignition properties, a micro-energetic igniter has been fabricated by the integration of the Al/Co3O4 nanothermite film with a semiconductor bridge microigniter. The thermite reactions between the nanoscale Al layer and the Co3O4 skeleton extensively promote the intensity of the spark, the length in duration and the size of the area, which greatly enhance the ignition reliability of the micro-energetic igniter. Moreover, this novel design enables the micro-energetic igniter to fire the pyrotechnic Zr/Pb3O4 in a gap of 3.7 mm by capacitor discharge stimulation and to keep the intrinsic instantaneity high and firing energy low. The realization of gap ignition will surely improve the safety level of initiating systems and have a significant impact on the design and application of explosive devices
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