An improved partial SPIHT with classified weighted rate-distortion optimization for interferential multispectral image compression

Based on the property analysis of interferential multispectral images, a novel compression algorithm of partial set partitioning in hierarchical trees (SPIHT) with classified weighted rate-distortion optimization is presented.After wavelet decomposition, partial SPIHT is applied to each zero tree independently by adaptively selecting one of three coding modes according to the probability of the significant coefficients in each bitplane.Meanwhile the interferential multispectral image is partitioned into two kinds of regions in terms of luminous intensity, and the rate-distortion slopes of zero trees are then lifted with classified weights according to their distortion contribution to the constructed spectrum.Finally a global ratedistortion optimization truncation is performed.Compared with the conventional methods, the proposed algorithm not only improves the performance in spatial domain but also reduces the distortion in spectral domain.     

IR Properties of Randomly Sea Surfaces

Sea surfaces should be considered as randomly rough surfaces at the infrared(IR) and optical bands. The geometric model of sea surfaces has been obtained by using image processing. Based on the electromagnetic scattering theory, the Laser Radar Cross Section(LRCS) for the sea surfaces is analyzed at IR band and the scattering properties of the sea surfaces have been gotten.     

Development and validation of a simple and sensitive high‐resolution LC/MS method for determination of PF‐04620110 in dog plasma: Application to a pharmacokinetic study

In this study, a more sensitive and reliable quantitative method based on ultra‐high performance liquid chromatography coupled with Q‐Exactive‐Orbitrap‐MS in full‐mass scan was developed and validated for the determination of PF‐04620110 in dog plasma. After protein precipitation with acetonitrile, the sample separations were carried out on an Acquity BEH C₁₈ column with 1 mm ammonium acetate in water and acetonitrile containing 0.1% acetic acid as mobile phase, at a flow rate of 0.4 mL/min. The assay showed excellent linearity over the concentration range of 1–2000 ng/mL with correlation coefficient >0.9980 (r > 0.9980). The LLOQ was 1 ng/mL. The inter‐ and intra‐day precision (RSD, %) was within 9.69% while the accuracy (RE, %) was in the range of ?8.59–11.24%. The extraction recovery was >85.37% and the assay was free of matrix effects. PF‐04620110 was demonstrated to be stable under various processing and handing conditions. The validated method was successfully applied to the pharmacokinetic study of PF‐04620110 in dogs and the results revealed that PF‐04620110 was slowly eliminated from plasma with a clearance of 60.81 ± 7.11 mL/h/kg for intravenous administration and 81.44 ± 25.79 mL/h/kg for oral administration. The oral bioavailability was determined to be 77.89% in dogs.     

Synthesis of asymmetrically substituted head‐to‐head polyacetylenes from 2,3‐disubstituted‐1,3‐butadienes

Asymmetrically substituted head‐to‐head polyacetylenes with phenyl and triphenylamine, thienyl or pyrenyl side groups were synthesized through anionic or controlled radical polymerization of 2,3‐disubstituted‐1,3‐butadienes and subsequent dehydrogenation process. Anionic polymerizations of the designed monomers bearing pendent triphenylamine and thienyl group gave narrow disperse disubstituted precursor polybutadienes with exclusive 1,4‐ or 4,1‐structure, which were confirmed by GPC and NMR measurements. In addition, the monomers possessing pyrenyl group were polymerized via nitroxide mediated radical polymerization and the resulting polymers were obtained with controlled molecular weight and low polydispersities. These polybutadiene precursors were then dehydrogenated in the presence of 2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquinone. Thus asymmetrically substituted head‐to‐head polyacetylenes were obtained as indicated by ¹H NMR. The properties of polybutadiene precursors and the corresponding polyacetylenes were analyzed by UV–vis, DSC, and TGA. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 395–402     

Gold nanoparticle-based colorimetric sensor for studying the interactions of β-amyloid peptide with metallic ions

In this paper, a kind of β-amyloid peptide (Aβ1-16) conjugated gold nanoparticles (Aβ1-16@GNPs) are prepared and employed as colorimetric indicator for studying the interaction of β-amyloid peptide with metallic ions (e.g. Zn²⁺ and Ca²⁺). In the presence of Zn²⁺, mono-dispersing Aβ1-16@GNPs enable to form aggregates or attach on the SHG-44 (human glioma cell) cellular surface which results in significant color change of the solution. The experimental results indicate that Zn²⁺ can interact with Aβ1-16 and form Zn²⁺-β-amyloid peptide complexes. In particular, in the presence of Zn²⁺, a time-dependent interaction of cells with Aβ1-16@GNPs has been observed that may suggest different expression levels of β-amyloid peptide related proteins in various cell cycles. In addition, the aggregating/binding process can be easily reversed by adding EDTA, a good chelated ligand of Zn²⁺, which gives further proof of the interaction mechanism.     

Label-free colorimetric aptasensor for sensitive detection of ochratoxin A utilizing hybridization chain reaction

The combination of high selectivity of aptamer with the peroxidase-mimicking property of DNAzyme has presented considerable opportunities for designing colorimetric aptasensor for detection of ochratoxin A (OTA). The activities of both aptamer (as biorecognition element) and DNAzyme (as signal amplification element) are blocked via base pairing in the hairpin structure. Hybridization chain reaction (HCR) between two hairpin DNAs was employed to further improve the sensitivity of this method. The presence of OTA triggers the opening of the hairpin structure and the beginning of HCR, which results in the release of many DNAzyme, and generates enhanced colorimetric signals, which is correlated to the amounts of OTA with linear range between 0.01 to 0.32 nM, and the limit of detection is 0.01 nM under optimal conditions. OTA in yellow rice wine and wheat flour samples was also detected using this method. We demonstrate that a new colorimetric method for the detection of OTA has been established, which is simple, easy to conduct, label-free, sensitive, high throughput, and cost-saving.     

Synthesis,Photophysical, and Electrochemical Properties of RuII Polypyridyl Complexes Bridged with two Tetrapodal Symmetric and one Asymmetric Ligands

Two symmetric tetrapodal ligands L^1–2 and one asymmetric tetrapodal ligand L³ based on 4,5‐diazafluoren have been synthesized and characterized. Ligands L^1–2 formed by the condensation of pentaerythrityl tetratosylate with 4,5‐diazafluoren‐9‐oxime and 9‐(4‐hydroxy)phenylimino‐4,5‐diazafluorene, respectively. L³ was prepared by two steps, 9‐(4‐hydroxy)phenylimino‐4,5‐diazafluorene reacted with pentaerythrityl tetratosylate affording 1,1′,1"‐tris[(4,5‐diazafluoren‐9‐ylimino)phenoxymethyl]‐1"′‐(p‐tosyloxymethyl)‐methane, which reacted with 4,5‐diazafluoren‐9‐oxime affording the asymmetric ligand L³. Three tetranuclear Ru^II complexes [(bpy)₈L^1–3Ru₄](PF₆)₈ (bpy = bipyridine) were obtained by the reaction of Ru(bpy)₂Cl₂ · 2H₂O with ligands L^1–3. Spectroscopic studies of these complexes exhibit metal‐to‐ligand charge transfer absorptions at 440–445 nm and emissions at 575–579 nm. The electrochemical behaviors of these complexes are consistent with one Ru^II‐based oxidation couple and three ligand‐centered reduction couples.     

Error detection using mode information of macroblocks for video transmission

A new method for error detection using mode information of macroblocks (MBs) is proposed. For decodable inter MBs, inter residues are calculated by adding up absolute values of received residual pixels and intra complexities are estimated by that of motion compensated reference blocks. If inter residues are larger than intra complexities by a predefined quantity, MBs are considered to be erroneous. For decodable intra MBs,the connective smoothness of the current MB with correctly decoded neighboring MBs is tested to find erroneous MBs. Combined with error concealment, the new method improves the quality of reconstructed images by about 0.5-1 dB in peak signal-noise ratio (PSNR).     

Cu(Ⅱ)离子诱导的β-淀粉样蛋白聚集抑制剂筛选及分子构效关系分析

阿尔茨海默症药物的开发对该疾病的治疗非常重要。利用纳米金为探针研究了13种化合物抑制Cu~(2+)诱导的β-淀粉样蛋白聚集的能力,筛选出了10种有效的抑制剂,并获得了抑制剂抑制能力与其分子结构间的关系,利用筛选出的抑制剂实现了β淀粉样蛋白聚集过程的抑制和H_2O_2产生量的减少,对阿尔茨海默症的研究具有重要意义。     

干涉多光谱卫星图像序列编码

星载干涉多光谱图像序列通过图像匹配实行定位形成光谱序列,相邻图像之间具有很强的相关性,与一般图像序列不同的是,相邻图像之间具有明显的平移特点。为了充分利用这一特点实现有效的图像压缩,同时减少编码系统复杂度,提出了一种新的图像序列编码方法,通过小波域系数匹配算法检测出相邻图像之间的相对位移量,然后对差值图像进行类似于单幅图像的编码,从而提高了总体编码效率。本算法具有与相同单幅图像编码算法相当的低复杂度特点,只需要对单幅图像与模板的差值进行基于小波变换的编码,从而避免了基于三维小波变换的编码算法对系统存储量要求大以及编码延时大的缺陷。仿真结果表明,本算法比基于三维小波变换的编码算法效果更好。