气相色谱-串联质谱法结合QuEChERS法快速检测中药中50种农药残留

目的 建立运用气相色谱-串联质谱（GC-MS/MS）法快速筛查460份中药材及其中药饮片（43份）中常用的50种农药残留。方法 通过对比《中国药典》2020版中药中农药残留的前处理方法,优选中药中50种农药残留的适配性前处理方法。中药样品经乙腈溶剂提取,以Qu ECh ERS法处理,采用GC-MS/MS测定,内标法定量。结果 在460份检测样品中共检出农药残留66份,总检出率为14.3%,检出禁用农药6份,检出率为1.3%,43份中药饮片中农药残留检出率为11.6%,未检出禁用农药。农残的检出是季节性分布集中出现在第3、4季度,农贸市场和种植地的农残检出率明显高于医院和药店,并且存在农残超标情况。中药中根类和叶类受污染最重,中药材全草类中农药残留最多,检出率为20.4%,其次为叶类18.3%和根茎类16.3%,中药饮片中农残最高为叶类,检出率为15.4%,全草类检出率为11.1%、根茎类检出率为6.2%,全草类、根茎类和叶类存在样品中检出多种农药残留的现象。结论 该方法简单快速、灵敏度高、重现性好、准确度高,可快速筛查中药中农药残留,为保障中药质量提供参考。     

CD47-retargeted oncolytic adenovirus armed with melanoma differentiation-associated gene-7/interleukin-24 suppresses in vivo leukemia cell growth

Our previous studies have suggested that harboring a soluble coxsackie-adenovirus receptor-ligand (sCAR-ligand) fusion protein expression cassette in the viral genome may provide a universal method to redirect oncolytic adenoviruses to various membrane receptors on cancer cells resisting to serotype 5 adenovirus infection. We report here a novel oncolytic adenovirus vector redirected to CD47+ leukemia cells though carrying a sCAR-4N1 expression cassette in the viral genome, forming Ad.4N1, in which 4N1 represents the C-terminal CD47-binding domain of thrombospondin-1. The infection and cytotoxicity of Ad.4N1 in leukemia cells were determined to be mediated by the 4N1-CD47 interaction. Ad.4N1 was further engineered to harbor a gene encoding melanoma differentiation-associated gene-7/interleukin-24 (mda-7/IL-24), forming Ad.4N1-IL24, which replicated dramatically faster than Ad.4N1, and elicited significantly enhanced antileukemia effect in vitro and in a HL60/Luc xenograft mouse model. Our data suggest that Ad.4N1 could act as a novel oncolytic adenovirus vector for CD47+ leukemia targeting gene transfer, and Ad.4N1 harboring anticancer genes may provide novel antileukemia agents.     

The application of subspace preconditioned LSQR algorithm for solving the electrocardiography inverse problem

Regularization is an effective method for the solution of ill-posed ECG inverse problems, such as computing epicardial potentials from body surface potentials. The aim of this work was to explore more robust regularization-based solutions through the application of subspace preconditioned LSQR (SP-LSQR) to the study of model-based ECG inverse problems. Here, we presented three different subspace splitting methods, i.e., SVD, wavelet transform and cosine transform schemes, to the design of the preconditioners for ill-posed problems, and to evaluate the performance of algorithms using a realistic heart-torso model simulation protocol. The results demonstrated that when compared with the LSQR, LSQR-Tik and Tik-LSQR method, the SP-LSQR produced higher efficiency and reconstructed more accurate epcicardial potential distributions. Amongst the three applied subspace splitting schemes, the SVD-based preconditioner yielded the best convergence rate and outperformed the other two in seeking the inverse solutions. Moreover, when optimized by the genetic algorithms (GA), the performances of SP-LSQR method were enhanced. The results from this investigation suggested that the SP-LSQR was a useful regularization technique for cardiac inverse problems.     

Core@shell structured Co–CoO@NC nanoparticles supported on nitrogen doped carbon with high catalytic activity for oxygen reduction reaction

A composite with a hierarchical structure consisting of nitrogen doped carbon nanosheets with the deposition of nitrogen doped carbon coated Co–CoO nanoparticles (Co–CoO@NC/NC) has been synthesized by a simple procedure involving the drying of the reaction mixture containing Co(NO₃)₂, glucose, and urea and its subsequent calcination. The drying step is found to be necessary to obtain a sample with small and uniformly sized Co–CoO nanoparticles. The calcination temperature has a great effect on the catalytic activity of the final product. Specifically, the sample prepared at the calcination temperature of 800 °C shows better catalytic activity of the oxygen reduction reaction (ORR). Urea in the reaction mixture is crucial to obtain the sample with the uniformly sized Co–CoO nanoparticles and also plays an important role in improving the catalytic activity of the Co–CoO@NC/NC. Additionally, there exists a strong electronic interaction between the Co–CoO nanoparticles and the NC. Most interestingly, the Co–CoO@NC/NC is highly efficient for the ORR and can deliver an ORR onset potential of 0.961 V vs. RHE and a half-wave potential of 0.868 V vs. RHE. Both the onset and half-wave potentials are higher than those of most catalysts reported previously and even close to those of the commercial Pt/C (the ORR onset and half-wave potential of the Pt/C are 0.962 and 0.861 V vs. RHE, respectively). This, together with its high stability, strongly suggests that the Co–CoO@NC/NC could be used as an efficient catalyst for the ORR.

A simple method has been developed for the synthesis of Co–CoO@NC/NC, which exhibits high and stable performance for the ORR.     

Erythrocyte reduced/oxidized glutathione and serum thiol/disulfide homeostasis in patients with rheumatoid arthritis

BackgroundChronic inflammation and oxidative stress are the most known mechanisms in Rheumatoid Arthritis (RA) pathophysiology, which is still not fully elucidated. In this study, we evaluated oxidative status by determining intracellular reduced/oxidized glutathione (GSH/GSSG) homeostasis and serum thiol/disulfide (SH/SS) homeostasis in RA patients.MethodsA total of 152 RA patient and 89 healthy controls were included in the study. RA patients were subdivided according to disease activity score-28 (DAS-28) as active RA and remission RA. Intracellular GSH/GSSG and serum SH/SS homeostasis parameters were analyzed.ResultsMedian (1st–3rd quartile values) SS/SH and GSSG/GSH percent ratio levels were significantly higher in RA patients (6.94 (6.02–8.54) and 69.8 (44.05–85.29); respectively) compared to controls (4.62 (4.15–5.46) and 34.9 (22.43–62.2); respectively) (p < 0.05 for all). SS/SH and GSSG/GSH percent ratio levels were significantly higher in active RA patients when compared to remission RA patients and controls (p < 0.05 for all). SS/SH and GSSG/GSH percent ratios were significantly increased in remission RA group compared to controls (p < 0.05 for all). DAS28 scores were positively correlated with SS/SH and GSSG/GSH percent ratios (rho = 0.259 and 0.296; respectively).ConclusionsThese findings suggest that active intracellular and extracellular thiol group oxidation process might play a role in RA pathogenesis and further work in these areas may be warranted to show potential value of evaluating intracellular GSSG/GSH and serum SH/SS balances together in disease monitoring.     

Development of a single-tube multiplex real-time PCR for detection and identification of five pathogenic targets by using melting-curve analysis with EvaGreen

SYBR Green I (SG) is widely used in real-time PCR applications as an intercalating dye. Preferential binding of SG during PCR and inhibition of PCR often result in failure to detect multiple amplicons in multiplex reactions. In the present study, a novel single-tube, multiplex real-time PCR with EvaGreen dye (EG) was developed and evaluated for simultaneous detection of pathogenic targets by using five potato viruses as models. The PCR products obtained using five sets of specific primers were analyzed by melting curve analysis. The assay could specifically detect and differentiate the five potato viruses by producing a distinct peak for each amplification product and exhibited a high reproducibility with coefficients of variation from 0.01 to 0.25 %. Detection sensitivity of the assay ranged from 100 to 500 copies/μL for each virus. The results of this study demonstrate that multiplex real-time PCR and melting-curve analysis with EG is a sensitive, specific and inexpensive method for simultaneous detection of multiple pathogens.     

Functional nanostructure-loaded three-dimensional graphene foam as a non-enzymatic electrochemical sensor for reagentless glucose detection

Non-enzymatic and reagentless electrochemical sensors for convenient and sensitive detection of glucose are highly desirable for prevention, diagnosis and treatment of diabetes owing to their unique merits of simplicity and easy operation. Facile fabrication of a three-dimensional (3D) sensing interface with non-enzymatic recognition groups and an immobilized electrochemical probe remains challenge. Herein, a novel non-enzymatic electrochemical sensor was developed for the sensitive and reagentless detection of glucose by loading functional nanostructure on 3D graphene. Monolithic and macroporous 3D graphene (3DG) foam grown by chemical vapor deposition (CVD) served as the electrode scaffold. Prussian blue (PB) and gold nanoparticles (AuNPs) were first co-electrodeposited on 3DG (3DG/PB-AuNPs) as immobilized signal indicator and electron conductor. After a polydopamine (PDA) layer was introduced on 3DG/PB-AuNPs via facile self-polymerization of dopamine to stabilize internal PB probes and offer chemical reducibility, the second layer of AuNPs was in situ formed to assemble the recognition ligand, mercaptobenzoboric acid (MPBA). Owing to the high stability of PB and good affinity between MPBA and glucose, the non-enzymatic sensor was able to be used in reagentless detection of glucose with high selectivity, wide linear range (5 μM–65 μM) and low detection limit (1.5 μM). Furthermore, the sensor was used for the detection of glucose level in human serum samples.

A non-enzymatic electrochemical sensor was fabricated by loading functional nanostructure on three-dimensional graphene foam for reagentless detection of glucose with high sensitivity and stability.     

自适应用户界面研究综述

自适应方式是人机交互领域的一项重要研究内容,也是解决目前系统、软件功能过剩问题的有效解决途径。本文介绍了目前应用在自适应用户界面的主要方式、自适应算法,以及自适应的属性,并讨论了自适应用户界面面临的问题和未来发展。