关于完全完备分配格上矩阵相对于特征值的特征向量

借助于伪补和矩阵的幂序列研究了完全完备分配格上矩阵相对于特征值的特征向量的计算方法,利用特征向量的性质证明了最大特征向量的计算公式,并给出了一般特征向量的计算方法.     

Simulation and feature analysis for gas emboli Doppler ultrasound signals

The purpose of this study is to establish the simulation model of the gas emboli by analyzing reasons for features of gas emboli Doppler ultrasound signals.It is useful for the further classification of the solid emboli and gas emboli.First,the model of the radiation force and the drag force is used to calculate forces acting on the gas emboli.Second,the acceleration of the gas emboli is calculated in both the radial direction and the axial direction of the vessel, which is used to calculate the trajectory of the gas emboli in the vessel.Finally,the computer simulation model is established for the gas emboli.Doppler ultrasound signals of the gas emboli and the solid emboli are generated in the simulation experiment.Experimental results show that compared with the solid emboli,the gas emboli acted by the radiation force and the drag force will result in the frequency-domain broaden in the Doppler spectrogram.When the gas emboli circulate from the low speed area to the high speed one and then from the high speed area back to the low speed one,a "V" shape will be shown in the spectrogram of gas emboli signals.When the gas emboli circulate from the low speed area to the high speed one or from the high speed area to the low speed one,a diagonal shape will be shown for gas emboli signals. It is also shown that features of simulated gas emboli signals match with those of gas emboli signals sampled from clinic.All demonstrate that the simulation method of the gas emboli is reasonable.     

Spatial variability and radiation assessment of the radionuclides in soils and sediments around a uranium tailings reservoir,south of China

Journal of Radioanalytical and Nuclear Chemistry - The concentrations of 238U, 226Ra, 232Th and 40K and gross α, β were measured in soils and sediments around a uranium tailings reservoir...     

Simultaneous quantitation of 23 bioactive compounds in Tanreqing capsule by high‐performance liquid chromatography electrospray ionization tandem mass spectrometry

Tanreqing capsule (TRQC) is a formulation frequently used in traditional Chinese medicine to treat pyrexia, cough, expectoration and pharyngalgia. Since the pharmacological action of traditional Chinese medicines is closely related to their complex and diverse constituents, understanding the exact composition of TRQC is important to elucidate its clinical effectiveness and mechanism of action as well as to establish quality control methods and resolve safety issues. Herein, we employed high‐performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry for the simultaneous quantitation of 23 bioactive compounds in five batches of TRQC; the analytes could be categorized into five types: organic acids (seven compounds), flavonoids (10 compounds), iridoids (two compounds), phenylethanoid glycosides (two compounds) and bile acids (two compounds). The calibration curves for all analytes showed good linearity (r > 0.9953), and the inter‐ and intra‐day precisions did not exceed 4.94 and 4.97%, respectively. The recoveries varied from 90.47% to 109.80%; the corresponding relative standard deviations (RSDs) did not exceed 4.94%; and the repeatability (RSD < 4.72%) and stability (RSD < 4.88%) were also within acceptable limits. Thus, this study can be viewed as a fundamental reference for setting comprehensive TRQC quality standards.     

Development of a Glassy Carbon Electrode Modified with Graphene/Au Nanoparticles for Determination of Acetaminophen in Pharmaceutical Preparation

Russian Journal of Electrochemistry - A graphene/Au nanoparticles composite modified glassy carbon electrode (GR/AuNPs/GCE) was developed. Electrochemical behavior of acetaminophen (ACOP) at this...     

Screening and identification of Caulis Sinomenii bioactive ingredients with dual‐target NF‐κB inhibition and β2‐AR agonizing activities

Caulis Sinomenii (CS) is a valuable traditional medicine in China. Its extract can act as an anti‐inflammatory agent and a vascular smooth muscle relaxant. However, the underlying mechanisms remain unknown. In this study, we developed a simple dual‐target method based on ultra‐performance liquid chromatography/quadrupole time‐of‐flight mass spectrometry combined with a dual‐target bioactive screening assay for anti‐inflammatory and antispasmodic activities to characterize the chemical structure of various bioactive compounds of CS rapidly. Seven potential NF‐κB inhibitors were identified, including laudanosoline‐1‐O‐xylopyranose, 6‐O‐methyl‐laudanosoline‐1‐O‐glucopyranoside, menisperine, sinomenine, laurifoline, magnoflorine and norsinoacutin. Furthermore, IL‐6 and IL‐8 assays confirmed the anti‐inflammatory effects of these potential NF‐κB inhibitors, in which laudanosoline‐1‐O‐d ‐xylopyranose and menisperine were revealed as novel NF‐κB inhibitors. Among the seven identified alkaloids, three potential β₂‐adrenergic receptor agonists, including sinomenine, magnoflorine and laurifoline, were characterized using a luciferase reporter system to measure for the activity of β₂‐adrenergic receptor agonists. Finally, sinomenine, magnoflorine and laurifoline were identified not only as potential NF‐κB inhibitors but also as potential β₂‐adrenegic receptor agonists, which is the first time this has been reported. Molecular dynamic simulation and docking results suggest that the three dual‐bioactive constituents could not only inhibit Pseudomonas aeruginosa PAK strain‐induced inflammatory responses via a negative regulation of the Braf protein that participates in MAPK signaling pathway but also activate the β₂‐adrenegic receptor. These results suggest that CS extract has dual signaling activities with potential clinical application as a novel drug for asthma.     

3-O-Sulfation of Heparan Sulfate Enhances Tau Interaction and Cellular Uptake

Prion-like transcellular spreading of tau in Alzheimer's Disease (AD) is mediated by tau binding to cell surface heparan sulfate (HS). However, the structural determinants for tau–HS interaction are not well understood. Microarray and SPR assays of structurally defined HS oligosaccharides show that a rare 3-O-sulfation (3-O-S) of HS significantly enhances tau binding. In Hs3st1^−/− (HS 3-O-sulfotransferase-1 knockout) cells, reduced 3-O-S levels of HS diminished both cell surface binding and internalization of tau. In a cell culture, the addition of a 3-O-S HS 12-mer reduced both tau cell surface binding and cellular uptake. NMR titrations mapped 3-O-S binding sites to the microtubule binding repeat 2 (R2) and proline-rich region 2 (PRR2) of tau. Tau is only the seventh protein currently known to recognize HS 3-O-sulfation. Our work demonstrates that this rare 3-O-sulfation enhances tau–HS binding and likely the transcellular spread of tau, providing a novel target for disease-modifying treatment of AD and other tauopathies.