单片机作用系统的软件抗干扰技术研究与分析

单片机小巧、灵活、廉价、功能强大、使用方便在工作中被得到普遍应用,成为当今电子行业控制设备的流行产品.如此受欢迎也对单片机的可靠度产生更高的要求,影响可靠力的其中一个要素便是抗干扰程度.单片机别名微控制器,将多种组件结合在一起组成的微型计算机,会在特定地区运行受到区域环境的影响,考虑好系统的兼容性,克服干扰带来的一系列副影响.     

气相色谱-质谱法检测人血清样品中新型含氯阻燃剂德克隆

采用液液萃取,气相色谱-负离子化学电离质谱技术,建立了人体血清样品中新型含氯阻燃剂德克隆(DP)的分离分析方法.血清样品蛋白质变性后,采用液液萃取法提取脂肪,再采用浓H2SO4破坏法去除大部分脂肪,最后采用酸性硅胶柱进一步净化.净化后的样品经浓缩富集,采用气相色谱-负离子化学电离质谱仪测定样品中DP两种同分异构体的含量...     

论制约SPSS统计分析方法课程教学和学习的因素--以延安大学社会学专业为例

社会发展，对于数据统计分析也提出了越来越高的要求，对于社会学专业的学生来讲，一定要学习好SPSS统计分析方法课程。延安大学社会学专业因为各方面的条件所限，目前SPSS统计分析方法课程，无论在教学上，还是学习上，都存在一些制约因素，这要求我们一方面要正确认识存在问题，并敢于面对存在的问题；另一方面，要从延安大学社会学专业的实际情况和学生的发展与需求上考虑，提出可行的解决办法，解决SPSS统计分析课程在教学和学习上面临的问题，最终使延安大学的社会学专业能够办出自己的特色。     

Exploring the light-quark interaction

Two basic motivations for an upgraded JLab facility are the needs: to determine the essential nature of light-quark confinement and dynamical chiral symmetry breaking (DCSB); and to understand nucleon structure and spectroscopy in terms of QCD's elementary degrees of freedom. During the next ten years a programme of experiment and theory will be conducted that can address these questions. We present a Dyson-Schwinger equation perspective on this effort with numerous illustrations, amongst them: an interpretation of string-breaking; a symmetry-preserving truncation for mesons; the nucleon's strangeness σ-term; and the neutron's charge distribution.     

Design of a dual aptamer-based recognition strategy for human matrix metalloproteinase 9 protein by piezoelectric biosensors

MMP-9, human matrix metalloproteinase 9, belongs to the family of zinc-dependent peptide-bond hydrolases and is involved in the degradation of the extracellular matrix (ECM). In clinics, it is well known that elevated MMP-9 serum levels are associated with cardiovascular dysfunctions, several aspects of the physiology and pathology of the central nervous system, neuropsychiatric disorders and degenerative diseases related to brain tumors, and excitotoxic/neuroinflammatory processes. Due to the large interest of diagnostics in this protein, efforts to set up sensitive methods to detect MMP-9 for early diagnosis of a number of metabolic alterations are rapidly increasing. In this panorama, biosensors could play a key role; therefore we explored for the first time the development of an aptamer-based piezoelectric biosensor for a sensitive, label free, and real time detection of MMP-9. The detecting strategy involved two different aptamers in a sandwich-like approach able to detect down to 100 pg mL⁻¹ (1.2 pM) of MMP-9 as detection limit in standard solution. As proof of principle, commercial serum was investigated in terms of possible interferents, their identification and role in MMP-9 detection. The estimated detection limit for MMP-9 is about 560 pg mL⁻¹ (6.8 pM) in untreated serum.     

High‐performance liquid chromatographic method for the quantification of Mitragyna inermis alkaloids in order to perform pharmacokinetic studies

In Africa, Mitragyna inermis (Willd.) O. Kuntze (Rubiaceae) is commonly used in traditional medicine to treat malaria. Antimalarial activity is mostly due to the hydromethanolic extract of M. inermis leaves and especially to the main alkaloids, uncarine D and isorhynchophilline. In the present study, we describe for the first time an HPLC method for the simultaneous quantification of uncarine D and isorhynchophylline in biological matrices. SPE was used to extract the components and the internal standard naphthalene from human and pig plasma samples. Chromatographic separation was performed on a C‐18 reversed column at a flow rate of 1 mL/min, using methanol–phosphate buffer (10:90, pH 7), as a mobile phase. Good linearity was observed over the concentration ranges of 0.0662–3.31 μg/mL for uncarine D and 0.0476–2.38 μg/mL for isorynchophylline. The precision was less than 12% and the accuracy was from 86 to 107% without any discrepancy between the two species. Uncarine D and isorhynchophylline recoveries were over 80%. These results allowed the quantification of both uncarine D and isorhynchophylline in pig plasma after intravenous administration of M. inermis extract.     

Evaluation of unfolded-partial least-squares coupled to residual trilinearization for four-way calibration of folic acid and methotrexate in human serum samples

The combination of unfolded-partial least-squares (U-PLS) with a recently proposed separate procedure, known as residual trilinearization (RTL), has been successfully employed for four-way data calibration. The chemometric method employs the evolution of excitation-emission matrices (EEMs) with time, for the resolution of folic acid-methotrexate mixtures, in human serum samples. The fluorogenic products monitored correspond to the oxidation of the studied analytes with potassium permanganate, in slightly acidic medium. The reaction is developed in 7 min and followed using a fast-scanning spectrofluorimeter, capable of recording each complete EEM in 12 s. This allows the acquisition of 10 successive EEMs, at different reaction times, during the development of the oxidation reaction, given rise to the four-way data set employed. The procedure, which had been previously reported for urine determination, is extended to serum analysis in this work. The combination of U-PLS/RTL is providing enhanced predictive results in comparison with standard methods as PARAFAC and N-PLS, in the presence of human serum, where significant unexpected components and or inner filter effects may occur.     

HPLC‐ESI‐MS analysis of oral human fluids reveals that gingival crevicular fluid is the main source of oral thymosins β4 and β10

Thymosin β₄ (Tβ₄), its sulfoxide, and thymosin β₁₀ (Tβ₁₀) were detected in human saliva and identified by different strategies based on RP HPLC coupled to electrospray multidimensional IT MS. Tβ₄ was almost always detected in whole saliva, its sulfoxide sporadically, Tβ₁₀ rarely. Tβ₄ was undetectable in parotid saliva and less concentrated in submandibular/sublingual saliva than in whole saliva. Analysis of gingival crevicular fluid revealed high relative amounts of Tβ₄, Tβ₄ sulfoxide, and Tβ₁₀ in all the samples. Tβ₄ mean concentration was 200 times higher in crevicular fluid (20 μmol/L, N = 9) than in whole saliva (0.1 μmol/L, N = 9). Crevicular fluid concentration of Tβ₄ (ca. 5% represented by its sulfoxide) and β₁₀ significantly correlated (r = 0.856; N = 9), and their ratio was about 5. A significant correlation was also observed between Tβ₄ concentrations in whole saliva and gingival crevicular fluid (r = 0.738; N = 9). Immunohistochemical analysis of the major salivary glands showed that immunoreactivity for Tβ₄ is restricted to ductal cells, with minor degree of focal positivity in some acinar cells. On the whole, results indicate that gingival sulcus is a main, although not the sole, source for oral Tβ₄ and Tβ₁₀.