非线性时间序列数据中的关联维提取

本文将混沌方法引入具有非线性时间序列的降雨量分析。首先对有关混沌及关联维的概念作简单介绍,在确定降雨量数据具有混沌特征后,对其进行关联维提取,得到颇具意义的结果。     

Intermodality, retrospective image registration in the thorax

The purpose of this study was to develop an accurate, retrospectively applicable procedure for registering thoracic studies from different modalities in a short amount of time and with minimal operator intervention. METHODS: CT and PET studies were acquired from six patients. The pleural surfaces in both image sets were determined by segmenting based on 50% of the maximum soft-tissue value in the study. These surfaces were converted into three-dimensional volumes and used to register the CT and PET studies in three dimensions using a sum of least squares fitting approach. The registered PET study was then displayed in a hot metal scale overlayed on top of the gray scale CT study. The accuracy of the fit was evaluated through a phantom study and preliminary clinical evaluation. RESULTS: A phantom study was performed to determine the limits of this technique. The accuracy was determined to be less than 2.3 mm in the x and y direction and 3 mm in the z direction. Preliminary clinical evaluation was also performed with encouraging results. CONCLUSION: This technique accurately registers PET and CT images of the thorax, retrospectively, without the need for external fiducial markers or other a priori action.     

用生态模式建设城市河流防护工程刍议

在城市河流防护工程实践中,传统砌石、混凝土等护砌方式在达到一定的功能目的的同时,产生了许多消极后果。针对用生态模式建设城市河流防护工程,恢复并保护自然水环境进行研究与探讨,可为山东三大工程提供有关技术的可行性与技术支持,做好科技服务。     

Results of a 90-day toxicity study on 1,2,3- and 1,1,2-trichloropropane administered via the drinking water

Trichloropropanes have been identified as environmental contaminants in sediments of the Great Lakes region of North America. Since these chemicals had the potential to find their way into drinking water, a 90-day feeding study was carried out in order to determine their subchronic toxicity. Groups of 10 male and 10 female weanling Sprague-Dawley rats were supplied drinking water ad libitum, containing 1,2,3- or 1,1,2-trichloropropane at concentrations of 1, 10, 100 or 1000 mg/L for 13 weeks. Emulphor (0.5%) was used to solubilize the chemicals. At the end of the study, the animals were killed and examined for gross and microscopic changes. Heart, liver, brain, kidney and spleen were excised and weighed. Blood was collected and subjected to a comprehensive hematological analysis. Serum was collected and profiled for changes in 12 biochemical parameters and a portion of liver was used to determine mixed function oxidase activity. Although three animals died during the study, their deaths could not be related to treatment. Decreased growth rate was observed in both sexes of the group receiving 1000 mg/L 1,2,3-trichloropropane. There was an increase in liver, kidney and brain weights (relative to body weight) in rats of both sexes fed 1000 mg/L 1,2,3-trichloropropane. Fatty livers were observed in some of the treated animals but a clear dose-relationship was not evident. An elevation in serum cholesterol was observed in female rats fed the highest dose of 1,2,3-trichloropropane. This chemical also induced hepatic aminopyrine demethylase and aniline hydroxylase activities in male rats at the highest dose. Administration of both isomers produced only mild histological changes in the liver, thyroid and kidney of rats at the highest dose. The changes in the liver consisted of an increase in cytoplasmic eosinophilia in the periportal area together with vesiculation of biliary epithelial nuclei. Morphological changes were characterized by increased anisokaryosis in the proximal epithelium and occasional pyknosis associated with the accumulation of large eosinophilic inclusions. Changes in the thyroid consisted of a mild reduction in follicular size associated with an increased epithelial height. In general, these changes were more severe in the males than females, but were still mild overall. It was concluded that the no-effect level for both chemicals was 100 mg/L (15–20 mg/kg bw/day) and based on effects on growth rate and other changes, the 1,2,3- isomer was judged to be slightly more toxic than the 1,1,2- isomer.     

Growth temperature dependence of low-noise MESFET in molecular-beam epitaxy

The substrate growth temperature dependence of electrical properties for a low-noise MESFET fabricated on MBE-grown material has been demonstrated. The optimum noise figure and its associated gain were attributed to the higher epilayer quality and mobility at a growth temperature of 650°C between temperatures of 550°C and 700°C.     

广义Foster定理

利用Ｍａｘｗｅｌｌ方程组导出了适用于有耗网络的广义Ｆｏｓｔｅｒ定理，得到了一些有关电抗斜率以及Ｑ值的有用公式及结论。     

One-stage sternal stenting with homograft bone after cardiac operation in pediatric patients

Low cardiac output after open heart operations in neonates and infants carries a high mortality. Delayed sternal closure may be life-saving but may prolong hospital stay and increase costs. To circumvent these issues, we shaped homograft bone and interposed it between the sternal edges to allow primary wound closure in 2 pediatric patients. Midterm results are satisfactory.     

Evaluation of the proline-rich antigen of Coccidioides immitis as a vaccine candidate in mice

We have expressed the proline-rich antigen (PRA) from Coccidioides immitis in Escherichia coli and evaluated its potential as a vaccine candidate. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of the recombinant protein (rPRA) revealed two bands, which exhibited virtually identical primary amino acid sequences. T cells from rPRA-immunized BALB/c mice showed a significant in vitro proliferative response to rPRA. A small but statistically significant proliferative response was also induced by rPRA in T cells from mice immunized with whole-cell coccidioidal vaccines. BALB/c mice immunized with rPRA and challenged intraperitoneally with virulent C. immitis had a greatly reduced fungal burden in their lungs and spleens compared to unvaccinated mice. The number of organisms in the lungs was reduced 500-fold, and similar reductions were observed in the spleens of immunized mice. These studies support the continued development of rPRA as a candidate vaccine for prevention of coccidioidomycosis.     

Synthesis and Properties of the Bi-Based Superconducting Powder Prepared by the Pechini Process

Bi-based superconductors are of great interest in high-temperature superconductors. We describe what is believed to be the first synthesis of these materials using the Pechini process, a low-temperature synthetic method that often yields inorganic oxide of excellent phase purity and well-controlled stoichiometry. Using this process, it has been possible to synthesize phase-pure Bi-2223 phase by calcining the appropriate polymeric precursors in air at 800°C for several hours. The superconductivity studies show that the Pechini-synthesized materials appear to offer high-quality performance.