Male-Specific W4P/R Mutation in the Pre-S1 Region of Hepatitis B Virus, Increasing the Risk of Progression of Liver Diseases in Chronic Patients

The issue of hepatitis B virus (HBV) mutations possibly leading to a gender disparity in the progression of liver diseases has not been explored. We aimed to elucidate the relationships of the novel pre-S1 mutations, W4P/R, with the progression of liver diseases and male predominance in a South Korean chronic cohort by use of a molecular epidemiologic study. We developed a fluorescence resonance energy transfer (FRET)-based real-time PCR (RT-PCR) assay for the detection of the W4P/R mutations and applied it to 292 chronic HBV patients. The pre-S1 mutations from 247 (84.6%) of a total of 292 patients were detected by this assay. W4P/R mutants were found to be significantly related to severe liver diseases (hepatocellular carcinoma [HCC] and liver cirrhosis, 12.4% [19/153] of patients, versus chronic hepatitis and asymptomatic carriage, 1.1% [1/94] of patients) (P<0.001). All of the W4P/R mutants were found in males only. The novel HBV pre-S1 mutations, W4P/R, may be associated with disease severity in male patients chronically infected with HBV genotype C. The W4P/R mutations may provide in part an explanation for the relatively high ratio of male to female incidence in HCC generation in South Korean chronic HBV patients.OAIID:oai:osos.snu.ac.kr:snu2013-01/102/0000006653/6SEQ:6PERF_CD:SNU2013-01EVAL_ITEM_CD:102USER_ID:0000006653ADJUST_YN:YEMP_ID:A077651DEPT_CD:806CITE_RATE:4.068FILENAME:male-specific w4p_r mutation in the pre-s1.pdfDEPT_NM:의과학과EMAIL:[email protected]_YN:YCONFIRM:

Microstructural evolution induced by micro-cracking during fast lithiation of single-crystalline silicon

h i g h l i g h t s Lithiation of Si results in various microstructures depending of crystal orientation. A complex vein-like microstructure of Li x Si was observed in {100} oriented Si. Micro-cracks provide a fast path for Li diffusion and cause a non-uniform lithiation. Crystalline Li x Si plays an important role in micro-crack generation. a r t i c l e i n f o t r a c t We report observations of microstructural changes in {100} and {110} oriented silicon wafers during initial lithiation under relatively high current densities. Evolution of the microstructure during lithiation was found to depend on the crystallographic orientation of the silicon wafers. In {110} silicon wafers, the phase boundary between silicon and Li x Si remained flat and parallel to the surface. In contrast, lithiation of the {100} oriented substrate resulted in a complex vein-like microstructure of Li x Si in a crystalline silicon matrix. A simple calculation demonstrates that the formation of such structures is energetically unfavorable in the absence of defects due to the large hydrostatic stresses that develop. However, TEM observations revealed micro-cracks in the {100} silicon wafer, which can create fast diffusion paths for lithium and contribute to the formation of a complex vein-like Li x Si network. This defect-induced microstructure can significantly affect the subsequent delithiation and following cycles, resulting in degradation of the electrode

Plasma Cell Granuloma Associated with Pulmonary Actinomycosis: A Case Report

Plasma cell granuloma (PCG) of the lung is a rare disease that usually presents as a pulmonary nodule or mass on incidental radiographic examination without symptoms. Although the etiology of PCG is still controversial, many findings have lent support to the lesion being a reactive inflammatory process rather than a neoplastic one. We describe a 53-yr-old male who presented with a hemoptysis and have a lung mass at the left upper lobe on chest radiograph. The lung mass was primarily diagnosed as PCG by percutaneous needle aspiration and biopsy, and the patient was treated with oral steroid because he and relatives refused the operation. However, the size of the lung mass did not change and open thoracotomy and lobectomy were done therefore. He was confirmed as having pulmonary actinomycosis with PCG after surgery. To our knowledge, this is the first report of PCG associated with actinomycosis in Korea

Clear Cell "Sugar" Tumor of the Lung: A Well-Enhanced Mass with an Early Washout Pattern on Dynamic Contrast-Enhanced Computed Tomography

Clear cell tumor of the lung is a rare and very unusual benign pulmonary tumor. As clear cell tumor of the lung contains abundant cytoplasmic glycogen, this tumor is called "sugar tumor". We report a case of sugar tumor in a 64-yr-old man presenting as a round pulmonary nodule. On dynamic computed tomography (CT) scans, the solitary pulmonary nodule showed early wash-in enhancement with an early washout pattern like a lung malignancy. The patient underwent wedge resection for the tumor. Pathologic examination, including immunohistochemical studies, revealed that the nodule was a benign clear cell tumor, so-called "sugar tumor". Because only a small number of cases have been reported previously, clinical aspects, radiological characteristics on dynamic contrast-enhanced CT, and differential diagnosis of the tumor are not well established. Herein we present a clear cell tumor of the lung and discuss the clinical, radiological, and pathological features of the tumor

Data Mining in Tree-Based Models and Large-Scale Contingency Tables

This thesis is composed of two parts. The first part pertains to tree-based models. The second part deals with multiple testing in large-scale contingency tables. Tree-based models have gained enormous popularity in statistical modeling and data mining. We propose a novel tree-pruning algorithm called frontier-based tree-pruning algorithm (FBP). The new method has an order of computational complexity comparable to cost-complexity pruning (CCP). Regarding tree pruning, it provides a full spectrum of information. Numerical study on real data sets reveals a surprise: in the complexity-penalization approach, most of the tree sizes are inadmissible. FBP facilitates a more faithful implementation of cross validation, which is favored by simulations. One of the most common test procedures using two-way contingency tables is the test of independence between two categorizations. Current test procedures such as chi-square or likelihood ratio tests provide overall independency but bring limited information about the nature of the association in contingency tables. We propose an approach of testing independence of categories in individual cells of contingency tables based on a multiple testing framework. We then employ the proposed method to identify the patterns of pair-wise associations between amino acids involved in beta-sheet bridges of proteins. We identify a number of amino acid pairs that exhibit either strong or weak association. These patterns provide useful information for algorithms that predict secondary and tertiary structures of proteins.Ph.D.Committee Chair: Tsui, Kwok-Leung; Committee Member: Goldsman, David; Committee Member: Huo, Xiaoming; Committee Member: Lee, Wenke; Committee Member: Wu, Josep

Unsupervised feature selection using weighted principal components. Expert Systems with Applications

Abstract Feature selection has received considerable attention in various areas as a way to select informative features and to simplify the statistical model through dimensional reduction. One of the most widely used methods for dimensional reduction includes principal component analysi