A Study of Grid Artifacts Formation and Elimination in Computed Radiographic Images

Computed radiography (CR) has many advantages such as filmless operations, efficiency, and convenience. Furthermore, it is easier to integrate with the picture archiving and communication systems. Another important advantage is that CR images generally have a wider dynamic range than conventional screen film. Unfortunately, grid artifacts and moiré pattern artifacts may be present in CR images. These artifacts become a more serious problem when viewing CR images on a computer monitor when a clinic grade monitor is not available. Images produced using a grid with higher frequency or a Potter–Bucky grid (i.e., a moving grid, Bucky for short) can reduce occurrence but cannot guarantee elimination of these artifacts [CR & PACS (2000); Detrick F (2001), pp 7–8]. In this paper, the formation of the artifacts is studied. We show that the grid artifacts occur in a narrow band of frequency in the frequency domain. The frequency can be determined, accurately located, and thus removed from the frequency domain. When comparing the results obtained from the proposed method against the results obtained using previous computer methods, we show that our method can achieve better image quality.     

Prognostic significance of caspase-3 expression in primary resected esophageal squamous cell carcinoma.

AIMS: The present study retrospectively examines the expression of caspase-3 in primary resected esophageal squamous cell carcinoma (ESCC) and the correlation between the outcome of patients and the expression of proteins. METHODS: Immunohistochemistry and Western blot analyses were used to analyse the expression of caspase-3 in 40 archival specimens of patients with primary resected ESCC. RESULTS: According to our cut-off point of the staining for caspase-3, 24 (60%) cases were positive and 16 (40%) negative. Caspase-3 expression correlated with a significant favorable prognosis in primary resected ESCC (P=0.02). A multivariate analysis of clinical and biological factors indicated that stage, tumor differentiation, and caspase-3 expression were independent prognostic factors. CONCLUSIONS: Caspase-3 expression might be a good and new prognostic indicator for primary resected ESCC.     

Heterogeneity of human blood monocyte: two subpopulations with different sizes, phenotypes and functions.

Human blood mononuclear cells from normal adults were collected after density-cut centrifugation and monocytes were then isolated by removal of lymphocytes using the techniques of E-rosetting and cell adhesion. The purified monocytes were further analysed by velocity sedimentation, and two distinct subpopulations with different cell sizes were obtained. The larger monocytes were 17.0 +/- 1.8 microns in diameter with a mean sedimentation rate (SR) of 7.0 +/- 0.6 mm/hr, while the smaller monocytes were 9.5 +/- 0.8 microns in size and 4.1 +/- 0.2 mm/hr in SR. The population ratio of larger:smaller cells was approximately 2:1 (66 +/- 2.8%:34 +/- 1.6%). Both cell populations exhibited a high positive rate (> 98%) in both the non-specific esterase and the peroxidase stain. However, the larger cells had much higher phagocytic activity than the smaller ones. Furthermore, the expression of monocyte-associated antigens was also different between these two subpopulations. Thus, while most of the larger monocytes (98%) could be recognized by monoclonal antibodies MY7 and OKM1, only some (35 and 61%, respectively) of the smaller monocytes could react with those antibodies. In addition, the larger monocytes secreted a significant amount of monokines including interleukin-1 beta (IL-1 beta), tumour necrosis factor-alpha (TNF-alpha) and prostaglandin E2 (PGE2) and their production increased in proportion to the level of stimulation by bacterial lipopolysaccharide (LPS), whereas the production of monokines by the smaller monocytes remained at low levels and did not respond to LPS stimulation. These results reveal the existence of phenotypic and functional heterogeneity in human blood monocytes.     

卡那霉素链霉菌噬菌体SKJ1DNA限制性内切酶图谱的构建

卡那霉素链霉菌温和性噬菌体ＳＫＪ１ＤＮＡ上有２个ＡｖａＩ和ＳｍａＩ酶切位点，８个ＳａｌＩ位点，７个ＥｃｏＲＩ位点及１２个ＢａｍＨＩ位点，经酶切后用１％琼脂糖凝胶电泳测定ＳＫＪ１ＤＮＡ大小为６０．７ｋｂ。用单酶切，双酶切及片段酶切分析，得到ＳＫＪ１ＤＮＡ的ＡｖａＩ、ＳｍａＩ、ＥｃｏＲＩ、ＳａｌＩ酶切图谱及ＢａｍＩ１的部分酶切图谱，证明ＡｖａＩ和ＳｍａＩ在ＳＫＪ１ＤＮＡ上具有相同酶切位点，并经过酶切结     

Effects of Glucocorticoid on Electrical Activities of Hippocampal Neurons in vitro

Intracellular recording of the rat hippocampal slices was established and usedto analyse the effects of glucocorticoid on resting membrane potential as well as inputresistance of the cells in CA1 and CA2 of hippocampal slices.The results indicate thatwithin 1-2 min the steroid hyperpolarized some of the hippocampal neurons with atendency of increasing the cells' input resistance,suggesting that glucocorticoid caninfluence the function of central neurons in a non-genomic pattern,and the underlyingmechanism involves the change of resting membrane potential.     

综合疗法和加用人胎肝细胞悬液治疗重症肝炎30例疗效比较

重症肝炎30例随机分为两组,采用综合疗法治疗15例;另15例在综合疗法基础上加用人胎肝细胞悬液。综合治疗组病死比例为9/15例;胎肝组病死比例为4/15例,较综合疗法组明显为低。胎肝组存活11例平均退黄时间为55.4±25.4天;综合疗法组存活6例,平均退黄时间为119.7±54.9天,前者明显短于后者(P<0.01)。对胎肝组12例患者作输注前后凝血酶元时间活动度对比观察,输注后48h凝血酶元时间活动度可提高18.9％。     

更年期妇女生理心理健康状况探讨

目的探讨更年期妇女生理、心理健康状况及相互关系 ,为进一步缓解更年期妇女的症状提供医疗和护理上的依据。方法对北京大学第一临床医院更年期门诊病人进行问卷调查 ,数据结果应用SPSS 8 0数据分析软件包进行处理。结果更年期妇女Kupperman总体平均分为 2 0 12± 9 97分 ,SCL 90评分量表总体平均分为 4 6 6 2±36 2 8分 ,并且以潮热出汗、失眠等躯体症状 ,以及强迫症状、人际关系敏感、抑郁、焦虑等心理症状表现突出。应用激素替代疗法后 ,能有效缓解更年期妇女潮热出汗、抑郁心烦、疲乏、骨关节痛、敌对的症状 ,与未用激素替代疗法者有显著差异。对更年期妇女的生理、心理进行分析显示 ,更年期妇女生理心理症状呈中等程度相关性 (r=0 6 17,P <0 0 0 1)。结论医护人员应加强对更年期妇女生理心理双方面的关注。