Studies of Transformation and Particle-Binding of Resin Acids During Oxidative Treatment of Effluent from Two New Zealand Pulp Mills

Reactor studies of aerobic degradation of effluent from the first and last ponds of the treatment system of two New Zealand pulp and paper mills indicated that filterable BOD₅, resin acids and transformed resin acids, free and bound, degraded at similar rates. During oxidative treatment the resin acids of untreated effluent became increasingly bound to particulate material and a sediment high in abiet-13-enoic acid was formed.     

固态相变对钴铬合金的金瓷匹配性的影响

目的研究钴铬（Co-Cr）合金在烤瓷过程中发生的固态相变对其金瓷匹配性的影响。方法失蜡法铸造Co-Cr、镍铬（Ni-Cr）合金的片状试件各9个,尺寸为25 mm×3 mm×0.5 mm,其中6个用于测定金瓷结合强度（三点弯曲法）,3个去瓷后进行X射线衍射（XRD）分析。铸造2种合金的棒状试件各1个,测定合金的热膨胀系数,并记录冷却曲线。结果Ni-Cr、Co-Cr合金的金瓷结合强度分别为（49.1±3.40）、（40.9±2.02）MPa,二者间的差异具有统计学意义（P=0.00）。Ni-Cr合金与Co-Cr合金在20～500 ℃的平均热膨胀系数分别为13.9×10-6、13.8×10-6·K-1。XRD结果显示,Ni-Cr合金的主要相为奥氏体,Co-Cr合金由fcc相、hcp相及少量σ相组成。结论烤瓷冷却过程中,钴铬合金中的fcc相向hcp相的转变以及σ相的析出导致合金线收缩速度出现突变,降低了金瓷匹配性。     

Peripheral aberration measurements: elliptical pupil transformation and variations in horizontal coma across the visual field

Background: The aim was to determine the critical eccentricity at which two methods of elaborating peripheral wavefront measurements are significantly different and to characterise horizontal coma in healthy young adults. Methods: Peripheral aberrations were determined for 20 observers for central and eight peripheral gaze positions up to 20° using an IRX‐3 aberrometer. In one subject, additional measurements up to 40° were obtained. Two definitions of stretching coefficients were compared. The raw empirical data were compared with theoretical modelling. Results: For both 3.5 mm and 6.0 mm pupils, no significant differences were observed between recalculated and non‐recalculated elliptical pupils for both methods (p > 0.05) up to 20° eccentricity. For eccentricities greater than 20° and up to 40°, significant differences between circular and elliptical pupils at some eccentricities were apparent, which corresponded to theoretical models. Wide individual variations in horizontal coma across the peripheral field were observed. Conclusions: The data suggest that for eyes with average levels of aberrations, the elliptical transformation is of no practical importance for eccentricities up to 20°. In some cases the slope of horizontal coma was reversed compared with previous findings in normal eyes.     

红外图像的降噪技术与实现

红外图像是一种重要的信息源,广泛应用于军事、工业、医学等领域,由于红外图像清晰度差、对比度低、噪声大、容易受环境影响。必须对其进行降噪处理。本文概述了红外图像的降噪技术和实现方法,为实际红外图像处理中,降噪方法的选择和改进提供了参考。     

Huge pelvi-abdominal malignant inflammatory myofibroblastic tumor with rapid recurrence in a 14-year-old boy

Inflammatory myofibroblastic tumor(IMT) is an uncommon benign neoplasm with locally aggressive behavior but malignant change is rare.We report an unusual case of pelvic-abdominal inflammatory myofibroblastic tumor with malignant transformation in a 14-year-old boy presenting with abdominal pain and 9 kg body weight loss in one month.Computed tomography revealed a huge pelvi-abdominal mass(30 cm),possibly originating from the pelvic extraperitoneal space,protruding into the abdomen leading to upward displace...     

Correcting eddy current and motion effects by affine whole‐brain registrations: Evaluation of three‐dimensional distortions and comparison with slicewise correction

Eddy‐current (EC) and motion effects in diffusion‐tensor imaging (DTI) bias the estimation of quantitative diffusion indices, such as the fractional anisotropy. Both effects can be retrospectively corrected by registering the strongly distorted diffusion‐weighted images to less‐distorted T2‐weighted images acquired without diffusion weighting. Two different affine spatial transformations are usually employed for this correction: slicewise and whole‐brain transformations. However, a relation between estimated transformation parameters and EC distortions has not been established yet for the latter approach. In this study, a novel diffusion‐gradient‐direction–independent estimation of the EC field is proposed based solely on affine whole‐brain registration parameters. Using this model, it is demonstrated that a more distinct evaluation of the whole‐brain EC effects is possible if the through‐plane distortion was considered in addition to the well‐known in‐plane distortions. Moreover, a comparison of different whole‐brain registrations relative to a slicewise approach is performed, in terms of the relative tensor error. Our findings suggest that for appropriate intersubject comparison of DTI data, a whole‐brain registration containing nine affine parameters provides comparable performance (between 0 and 3%) to slicewise methods and can be performed in a fraction of the time. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.     

SWIFT detection of SPIO‐labeled stem cells grafted in the myocardium

We report initial results from studies using sweep imaging with Fourier transformation (SWIFT) to detect superparamagnetic iron oxide (SPIO) particle–labeled stem cells in the rat heart. In experiments performed on phantoms containing titanium balls or SPIO–labeled cells, frequency‐shifted signals surrounding the paramagnetic objects produced a pileup artifact visualized by SWIFT. Total signal intensity was retained to a much greater extent by SWIFT as compared to gradient echo imaging. SWIFT imaging of excised and in vivo hearts showed (a) reduced blooming artifact as compared with gradient echo imaging, which helped reduce ambiguity in the detection of SPIO–labeled cells; (b) enhancement of off‐resonance signals relative to the background in the imaginary component of images; and (c) detailed myocardial anatomy in magnitude images, which provided anatomic reference. These features suggest SWIFT can facilitate the detection of SPIO–laden cells in the cardiovascular system. Magn Reson Med 63:1154–1161, 2010. © 2010 Wiley‐Liss, Inc.     

健康人携带的沙门菌中沙门菌基因组岛1的鉴定及特性分析

目的 检测健康人携带的沙门菌中沙门菌基因组岛（SGI1）的分布情况及特性,分析其与细菌耐药性的关系.方法 采用PCR方法对5株第一类整合子阳性的沙门菌检测SGI1,分别检测其左侧、右侧部分和其中间的部分基因,以及环状形式和切除状态,通过接合转移及自然转化检测其可移动性.结果 一株鼠伤寒沙门菌携带SGI1,位于thdF和int2之间,且其多重耐药区含aadA2,floR,tetG,blaPSE-1基因,存在环状形式及切除状态,且可通过自然转化方式转移至其他菌株.结论 SGI1可通过自然转化方式转移到其他菌株,介导多重耐药的传播.     

基于小波域隐马尔可夫树模型的医学图像去噪

目的：为了更好地去除DR医学图像噪声。方法：通过分析其噪声来源,在小波去噪和小波域隐马尔可夫模型的基础上,进行改进,即引入了方差不变性变换来调整原始图像的噪声模型为高斯噪声模型;图像分解为不同频率的不同子带,而隐马尔可夫树模型则用来规划小波系数的边缘分布。结果：自然图像处理实验结果表明,与普通的小波去噪方法相比,该方法不但可以保留图像的边缘信息,而且能提高去嗓后图像的峰值信噪比。结论：同时用该方法处理DR图像．处理结果表明此方法在噪声去除、细节质量及骨骼锐化等方面比传统的高斯滤波及小坡阈值滤波等方法效果要好。     

上皮细胞间质转化与肿瘤

上皮细胞间质转化(EMT)是胚胎发育中基本的生理过程,最新研究发现,EMT对肿瘤的浸润和转移也具有重要影响,在肿瘤演进过程中,EMT涉及到多种分子机制及其构成的复杂网络.因而,对其机制及标记物的深入研究对侵袭性肿瘤具有重要的诊疗意义.