Integrating intensity and texture differences for robust changedetection

We propose a novel technique for robust change detection based upon the integration of intensity and texture differences between two frames. A new accurate texture difference measure based on the relations between gradient vectors is proposed. The mathematical analysis shows that the measure is robust with respect to noise and illumination changes. Two ways to integrate the intensity and texture differences have been developed. The first combines the two measures adaptively according to the weightage of texture evidence, while the second does it optimally with additional constraint of smoothness. The parameters of the algorithm are selected automatically based on a statistic analysis. An algorithm is developed for fast implementation. The computational complexity analysis indicates that the proposed technique can run in real-time. The experiment results are evaluated both visually and quantitatively. They show that by exploiting both intensity and texture differences for change detection, one can obtain much better segmentation results than using the intensity or structure difference alone.     

Electron transfer properties and electrocatalytic behavior of tyrosinase on ZnO nanorod

In this work, the adsorption of tyrosinase on ZnO nanorods and its electrocatalytic behaviors were investigated. The mushroom tyrosinase with low isoelectric point was expected to adhere on the positively charged surface of ZnO nanorods by electrostatic attraction in a neutral solution. Scanning electron microscope images and spectroscopic analysis demonstrated the adsorption of tyrosinase on ZnO nanorods and the adsorbed tyrosinase remain its bioactivity to a large extent. In the presence of tyrosinase, a roughly and cyathiform of nanosized ZnO films was obtained. This open, three-dimensioned ramiform structure made the move through and exchange the electron with GCE more easily, and thus accelerating the electron transfer between electroactive and GCE. The adsorbed tyrosinase could catalyze the oxidation of phenol and catechol. The linear concentration ranges were from 0.02 to 0.1 mM and 0.01 to 0.4 mM, for phenol and catechol, respectively. The apparent Michaelis-menten constant , a reflection of the enzymatic affinity, was 0.24 mM for phenol and 1.75 mM for catechol, which suggests a large affinity to phenolic compound. The proposed methods presented a way for further studies of the immobilization and electrochemistry of proteins on nanostructured materials.     

Biodegradable Photothermal and pH Responsive Calcium Carbonate@Phospholipid@Acetalated Dextran Hybrid Platform for Advancing Biomedical Applications

A biodegradable multifunctional carrier for combination therapy with high efficiency and low side effect is essential for effective cancer treatment and for advancing biomedical applications. Therapeutics combination could reduce multidrug resistance and minimize doses through synergism. This study develops biodegradable gold nanorods@calcium carbonate particles coated with pH‐responsive acetalated dextran and phospholipid as an advanced platform for the incorporation of versatile molecular targeted therapeutics, including hydrophilic and hydrophobic drugs, as well as the model enzyme, green fluorescent protein, or antibody. The developed calcium carbonate based hybrid particles show good biocompatibility, stability with photothermal, and pH responsiveness, which protect the payloads from premature release, and maintain the enzyme activity. The therapeutics co‐loaded CaCO₃ based hybrid particles efficiently induce cancer cell death and reduce the multidrug resistance and HER2 expression with synergism. The photothermal effects promote ultrafast therapeutics release and induce significant cytotoxicity. Importantly, Anti‐HER2 antibody or HER2 targeted therapeutic is more effective in reducing HER2 expression when combined with drug or drugs via synergism. Overall, the cheap and simply manufactured biodegradable hybrid platform has great potential for advancing biomedical applications, including targeted photothermal combination therapy by co‐delivery of different types of therapeutics, including molecular targeted drugs, antibodies, and enzymes.     

α－β滤波器的基本问题分析与仿真研究

针对α-β滤波器滤波增益随采样时刻的增加而减小的问题,提出了一种根据位置滤波平均误差、速率滤波平均误差以及速度滤波效果确定滤波增益下降截止时刻的方法,并分析了可能影响滤波增益下降截止时刻的因素。仿真结果表明：通过该方法确定的滤波增益下降截止时刻可以使α-β滤波器的滤波效果达到最佳;滤波增益下降截止时刻与目标采样间隔的相关性最强,与过程噪声的相关性次之,与量测噪声的相关性最弱。     

基于人工鱼群粒子滤波的信号源定位

针对传统粒子滤波算法精度不高、难以满足移动监测车对无线电信号源定位需求的问题,提出了一种基于人工鱼群粒子滤波的信号源定位方法。将人工鱼群算法的优化思想引入到粒子滤波中,通过觅食行为和聚群行为驱动粒子向最优位置移动,改善粒子的分布。结合移动监测车对信号源定位的需要,建立了信号源波达角定位( AOA)的数学模型,在Matlab环境下对人工鱼群粒子滤波算法的信号源定位进行了仿真。实验结果表明,在保证实时性的前提下,该方法定位结果的最大误差为0.101%,定位精度远大于粒子滤波定位方法的估计精度,是一种有效、可行的定位方法。     

Isotope dilution gas chromatography with mass spectrometry for the analysis of 4‐octyl phenol, 4‐nonylphenol,and bisphenol A in vegetable oils

By the combination of solid‐phase extraction as well as isotope dilution gas chromatography with mass spectrometry, a sensitive and reliable method for the determination of endocrine‐disrupting chemicals including bisphenol A, 4‐octylphenol, and 4‐nonylphenol in vegetable oils was established. The application of a silica/N‐(n‐propyl)ethylenediamine mixed solid‐phase extraction cartridge achieved relatively low matrix effects for bisphenol A, 4‐octylphenol, and 4‐nonylphenol in vegetable oils. Experiments were designed to evaluate the effects of derivatization, and the extraction parameters were optimized. The estimated limits of detection and quantification for bisphenol A, 4‐octylphenol, and 4‐nonylphenol were 0.83 and 2.5 μg/kg, respectively. In a spiked experiment in vegetable oils, the recovery of the added bisphenol A was 97.5–110.3%, recovery of the added 4‐octylphenol was 64.4–87.4%, and that of 4‐nonylphenol was 68.2–89.3%. This sensitive method was then applied to real vegetable oil samples from Zhejiang Province of China, and none of the target compounds were detected.     

Preparation and characterisation of laterally monofluorinated mesogenic benzimidazole-based compounds

Series of laterally monofluorinated compounds, 2-(4?-alkoxy-3-fluorobiphenyl-4-yl)-1H-benzimidazole derivatives (nPPF(3)Mx) bearing different substituents (H, CH₃, NO₂, coded as nPPF(3)MH, nPPF(3)MM and nPPF(3)MN, respectively) at 5-position, were prepared and their structures were characterised. According to the results from differential scanning calorimetry and polarising optical microscopy, the present compounds nPPF(3)Mx exhibit enantiotropic smectic mesophases, for which the mesophase ranges are 13–67 and 47–111°C on heating and cooling for nPPF(3)MH, 84–112 and 126–154°C for nPPF(3)MM, and 23–102 and 49–117°C for nPPF(3)MN, respectively. Compared to non-fluorinated analogues, monofluorinated nPPF(3)Mx have low melting/clearing points and display enhanced mesophase range both in heating and cooling, which are attributed to the disruption of the side-to-side intermolecular packing caused by the ortho lateral fluoro substituents and the increased dipole–dipole interaction between the polar fluoro-substituted molecules, respectively. It is noted that nPPF(3)MM and nPPF(3)MN show a much wider mesophase range than nPPF(3)MH, which suggest that the substituent at benzimidazole moiety can improve the mesophase stability.     

Preparation and properties of laterally multifluorinated benzoxazole-based nematic mesogens

Series of laterally multifluorinated heterocyclic compounds, 2-(2?,3-difluoro-4?-alkoxy-1,1?-biphenyl-4-yl)-benzoxazole derivatives (nPF(2)PF(3)Bx), are prepared and characterised. They mainly display enantiotropic nematic mesophases with wider mesophase ranges of 12–107°C (heating process) and 22–134°C (cooling process) than the corresponding analogues. The enhanced nematic mesophase stability is achieved via slightly increasing inter-ring twist angle with inter-ring lateral fluorine substitute in biphenyl unit, as well as through improving the molecular polarity with multifluorine substitutes. Meanwhile, two inter-ring lateral fluorine atoms lead to a decrease in melting/clearing points and a wide nematic mesophase range, which makes it possible for heterocyclic mesogens nPF(2)PF(3)Bx to use in nematic liquid crystal display mixtures.     

Facile synthesis of gallium ions immobilized and adenosine functionalized magnetic nanoparticles with high selectivity for multi-phosphopeptides

Despite recent advances in phosphoproteome research, detection and characterization of multi-phosphopeptides have remained a challenge. Here we present a novel IMAC strategy for effective extracting multi-phosphopeptides from complex samples, through Ga³⁺ chelation to the adenosine tri-phosphate (ATP)-functionalized magnetic nanoparticles (Ga³⁺-ATP-MNPs). The high specificity of Ga³⁺-ATP-MNPs was demonstrated by efficient enriching multi-phosphopeptides from the digest mixture of β-casein and BSA with molar ratio as low as 1:5000. Ga³⁺-ATP-MNPs were also successfully applied for the phosphoproteome analysis of rat liver mitochondria, resulting in the identification of 193 phosphopeptides with 331 phosphorylation sites from 158 phosphoproteins. In other words, 54.4% of the phosphopeptides trapped by Ga³⁺-ATP-MNPs were observed with more than one phosphorylated sites, resulting in significant improvement on the identification of peptides with multi-phosphorylated sites. The high specificity of Ga³⁺-ATP-MNPs towards multi-phosphopeptides may be due to the synergistic effect of the strong hydrophilic surface functionalized by ATP and the proper chelating strength provided by Ga³⁺. Moreover, the unique magnetic core of Ga³⁺-ATP-MNPs also facilitates the isolation process and on-plate enrichment for direct MALDI MS analysis with limit of detection as low as 30 amol. This new affinity-based protocol is expected to provide a powerful approach for characterizing multiple phosphorylation sites on proteins in complex and dilute analytes, which may be explored as complementary technique for improving the coverage of phosphoproteome.