Generalized sparse MRF appearance models

Image segmentation or registration approaches that rely on a local search paradigm (e.g, Active Appearance Models, Active Contours) require an initialization that provides for considerable overlap or a coarse localization of the object to be segmented or localized. In this paper we propose an approach that does not need such an initialization, but localizes anatomical structures in a global manner by formulating the localization task as the solution of a Markov Random Field (MRF).     

Czochralski-grown nitrogen-doped silicon: Electrical properties of MOS structures; A positron annihilation study

Czochralski-grown nitrogen-doped (NCZ) silicon was studied using different methods. Measurements of interface traps density, effective generation lifetime and effective surface generation velocity were performed on selected Metal-Oxide-Semiconductor (MOS) structures. Application of the positron annihilation technique (PAS)—pulsed low energy positron system (PLEPS)—was focused on the detection of nitrogen-related defects in NCZ silicon in the near surface region. PAS—PLEPS technique gave relevant results on p-type NCZ silicon. Low sensitivity in the application to n-type NCZ silicon discriminates the PAS—PLEPS technique and should be alternated by other experimental technique. On the other hand, more pertinent measurement of generation lifetime was performed on MOS structures with n-type Si. Although the generation lifetime decreases in NCZ silicon, considerable lateral homogenization of the relaxation time was observed on the wafer.     

Normal liver, spleen, and kidney dimensions in neonates, infants, and children: evaluation with sonography

OBJECTIVE: The objective of this study was to determine the normal range of dimensions for the liver, spleen, and kidney in healthy neonates, infants, and children. SUBJECTS AND METHODS: This prospective study involved 307 pediatric subjects (169 girls and 138 boys) with normal physical or sonographic findings who were examined because of problems unrelated to the measured organs. The subjects were 5 days to 16 years old. All measured organs were sonographically normal. At least two dimensions were obtained for each liver, spleen, and kidney. Relationships of the dimensions of these organs with sex, age, body weight, height, and body surface area were investigated. Suggested limits of normal dimensions were defined. RESULTS: Dimensions of the measured organs were not statistically different in boys and girls. Longitudinal dimensions of all three organs showed the best correlation with age, body weight, height, and body surface area. Height showed the strongest correlation of all. This correlation was a polynomial correlation. CONCLUSION: Determination of pathologic changes in size of the liver, spleen, and kidney necessitates knowing the normal range of dimensions for these organs in healthy neonates, infants, and children. Presented data are applicable in daily routine sonography. Body height should be considered the best criteria to correlate with longitudinal dimensions of these organs.     

Leukemic predisposition of mice transplanted with gene-modified hematopoietic precursors expressing flt3 ligand

flt3/flk-2 ligand (FL) is a cytokine that exhibits synergistic activities in combination with other early acting factors on subpopulations of hematopoietic stem/progenitor cells. In addition to normal hematopoietic precursors, expression of the FL receptor, flt3R, has been frequently demonstrated on the blast cells from patients with acute B-lineage lymphoblastic, myeloid, and biphenotypic (also known as hybrid or mixed) leukemias. Because many of these leukemic cell types express FL, the possibility has been raised that altered regulation of FL-mediated signaling might contribute to malignant transformation or expansion of the leukemic clone. In humans, FL is predominantly synthesized as a transmembrane protein that must undergo proteolytic cleavage to generate a soluble form. To investigate the consequences of constitutively expressing the analogous murine FL isoform in murine hematopoietic stem/progenitor cells, lethally irradiated syngeneic mice (18 total) were engrafted with post-5-fluorouracil-treated bone marrow cells transduced ex vivo with a recombinant retroviral vector (MSCV-FL) encoding murine transmembrane FL. Compared with control mice (8 total), MSCV-FL mice presented with a mild macrocytic anemia but were otherwise healthy for more than 5 months posttransplant (until 22 weeks). Subsequently, all primary MSCV-FL recipients observed for up to 1 year plus 83% (20 of 24) of secondary MSCV-FL animals that had received bone marrow from asymptomatic primary hosts reconstituted for 4 to 5 months developed transplantable hematologic malignancies (with mean latency periods of 30 and 23 weeks, respectively). Phenotypic and molecular analyses indicated that the tumor cells expressed flt3R and displayed B-cell and/or myeloid markers. These data, establishing that dysregulated expression of FL in primitive hematopoietic cells predisposes flt3R+ precursors to leukemic transformation, underscore a potential role of this cytokine/receptor combination in certain human leukemias.