Bayesian Classification Using Probabilistic Graphical Models

Bayesian Classifiers are used to classify unseen observations to one of the probable class category (also called class labels). Classification applications have one or more features and one or more class variables. Naïve Bayes Classifier is one of the simplest classifier used in practice. Though Naïve Bayes Classifier performs well in practice (in terms of its prediction accuracy), it assumes strong independence among features given class variable. Naïve Bayes assumption may reduce prediction accuracy when two or more features are dependent given class variable. In order to improve prediction accuracy, we can relax Naïve Bayes assumption and allow dependencies among features given class variable. Capturing feature dependencies more likely improves prediction accuracy for classification applications in which two (or more) features have some correlation given class variable. The purpose of this project is to exploit these feature dependencies to improve prediction by discovering them from input data. Probabilistic Graphical Model concepts are used to learn Bayesian Classifiers effectively and efficiently

Development of a microelectronic module Final report

Feasibility of operating gallium arsenide devices in high temperature microelectronic circuit

Study of the cavitating instability on a grooved Venturi profile

Cavitation is a limiting phenomenon in many domains of fluid mechanics. Instabilities of a partial cavity developed on an hydrofoil, a converging-diverging step or in an inter-blade channel in turbomachinery, have already been investigated and described in many previous works. The aim of this study is to evaluate a passive control method of the sheet cavity. According to operating conditions, cavitation can be described by two different regimes: an unstable regime with a cloud cavitation shedding and a stable regime with only a pulsating sheet cavity. Avoiding cloud cavitation can limit structure damages since a pulsating sheet cavity is less agressive. The surface condition of a converging-diverging step, like a Venturi-type obstacle, is here studied as a solution for a passive control of the cavitation. This study discusses the effect of an organized roughness, in the shape of longitudinal grooves, on the developed sheet cavity. Analyzes conducted with Laser Doppler Velocimetry, visualisations and pressure measurements show that the grooves geometry, and especially the groove depth, acts on the sheet cavity dynamics. Results show that modifying the surface condition, by varying the grooves geometry, can reduce cavity sheet length and even suppress the cloud cavitation shedding.Comment: Submitted to Journal of Fluids Engineerin

Study of passive control study of the cavitation instability on a venturi profile

This paper presents experimental and numerical results concerning the operation of a configuration that includes an axial pump and a bundle of tubes that mimics the cool source of a heat exchanger. The pump used in the tests has a low solidity and two blades designed in forced vortex, the tip clearance is approximately 3.87% of tip radius. The experimental measures of the characteristic curves and of the wall static pressure fluctuations signals upstream and downstream the pump and the exchanger were compared to the numerical results. The numerical simulations were carried out by using a Fluent code, with URANS (Unsteady Reynolds Averaged Navier-Stokes) approach and k-w SST turbulence model

Understanding the Role of Eed Deletion in Medulloblastoma

Medulloblastoma, the most common malignant pediatric brain cancer, is uniquely sensitive to DNA damage-inducing therapies, with conventional treatment resulting in an 80% 5-year survival rate. Researching the apoptotic pathways that make treatment effective in some tumors and how those pathways contribute to resistance in others may identify therapies that reduce the need for toxic radiation and chemotherapy. In cerebellar development, physiologic Sonic Hedgehog (SHH) signaling drives proliferation of cerebellar granule neuron progenitors (CGNPs). Similarly, pathologic SHH hyperactivation drives proliferation in SHH-subgroup medulloblastoma, which makes up 30% of medulloblastoma cases. SHH signaling upregulates target genes in part by preventing H3K27 trimethylation marks via the JMJD3/KDM6B demethylase complex. In differentiated cerebellar neurons, where SHH signaling is low, the polycomb repressive complex 2 (PRC2) silences SHH target genes by trimethylating H3K27 residues in regulatory regions. Our data show that blocking the PRC2 through genetic deletion has varying effects in different contexts. When the PRC2-component Eed is deleted in SHH-subtype medulloblastomas that form in mice engineered for SHH hyperactivation, the tumors show initially slower growth compared to tumors in Eed-intact controls; however, the mice have significantly poorer survival. Therefore, this study aims to understand the mechanisms of initially reduced tumor growth and ultimately more rapid tumor progression. Our recent single cell gene expression analysis showed that Eed deletion in CGNPs induced genes involved in muscle cell differentiation, including myogenin and troponin. We will characterize Eed-deleted medulloblastoma using fluorescence-activated cell sorting (FACS) as well as immunohistochemistry (IHC). The first aim of this study is to elucidate how cell cycle dynamics are altered in Eed-deleted medulloblastomas. The second aim of the study tests whether Eed deletion alters the levels of cell cycle markers, cell death, and aberrant expression of muscular proteins in SHH-driven medulloblastoma. Our cell cycle studies show that Eed deletion slows tumor growth in early development, but the tumor later develops EED independence, resulting in more rapid progression and decreased survival. Additionally, our data show that Eed deletion alters the expression of proteins related to proliferation, differentiation, apoptosis, and muscle development.Bachelor of Scienc

Study of passive control study of the cavitation instability on a venturi profile

This paper presents experimental and numerical results concerning the operation of a configuration that includes an axial pump and a bundle of tubes that mimics the cool source of a heat exchanger. The pump used in the tests has a low solidity and two blades designed in forced vortex, the tip clearance is approximately 3.87% of tip radius. The experimental measures of the characteristic curves and of the wall static pressure fluctuations signals upstream and downstream the pump and the exchanger were compared to the numerical results. The numerical simulations were carried out by using a Fluent code, with URANS (Unsteady Reynolds Averaged Navier-Stokes) approach and k-w SST turbulence model

Intestinal fungi contribute to development of alcoholic liver disease

This study was supported in part by NIH grants R01 AA020703, U01 AA021856 and by Award Number I01BX002213 from the Biomedical Laboratory Research & Development Service of the VA Office of Research and Development (to B.S.). K.H. was supported by a DFG (Deutsche Forschungsgemeinschaft) fellowship (HO/ 5690/1-1). S.B. was supported by a grant from the Swiss National Science Foundation (P2SKP3_158649). G.G. received funding from the Yale Liver Center NIH P30 DK34989 and R.B. from NIAAA grant U01 AA021908. A.K. received support from NIH grants RC2 AA019405, R01 AA020216 and R01 AA023417. G.D.B. is supported by funds from the Wellcome Trust. We acknowledge the Human Tissue and Cell Research (HTCR) Foundation for making human tissue available for research and Hepacult GmbH (Munich, Germany) for providing primary human hepatocytes for in vitro analyses. We thank Dr. Chien-Yu Lin Department of Medicine, Fu-Jen Catholic University, Taiwan for statistical analysis.Peer reviewedPublisher PD

A digital pathology tool for quantification of color features in histologic specimens.

In preclinical research, histological analysis of tissue samples is often limited to qualitative or semiquantitative scoring assessments. The reliability of this analysis can be impaired by the subjectivity of these approaches, even when read by experienced pathologists. Furthermore, the laborious nature of manual image assessments often leads to the analysis being restricted to a relatively small number of images that may not accurately represent the whole sample. Thus, there is a clear need for automated image analysis tools that can provide robust and rapid quantification of histologic samples from paraffin-embedded or cryopreserved tissues. To address this need, we have developed a color image analysis algorithm (DigiPath) to quantify distinct color features in histologic sections. We demonstrate the utility of this tool across multiple types of tissue samples and pathologic features, and compare results from our program to other quantitative approaches such as color thresholding and hand tracing. We believe this tool will enable more thorough and reliable characterization of histological samples to facilitate better rigor and reproducibility in tissue-based analyses

Expression of Hepatitis C Virus Core Protein in Hepatocytes Does Not Modulate Proliferation or Apoptosis of CD8+ T Cells

Hepatocytes are the primary targets of the hepatitis C virus (HCV). While immunosuppressive roles of HCV core protein have been found in several studies, it remains uncertain whether core protein expressed in hepatocytes rather than in immune cells affects the CD8+ T cell response. In order to transduce genes selectively into hepatocytes, we developed a baculoviral vector system that enabled primary hepatocytes to express a target epitope for CD8+ T cells, derived from ovalbumin (OVA), with or without HCV core protein. Culture of OVA-specific CD8+ T cells with hepatocytes infected with these baculoviral vectors revealed that core protein has no effect on proliferation or apoptosis of CD8+ T cells. Our results suggest that HCV core protein does not exert its suppressive role on the CD8+ T cell immune response through expression in hepatocytes

Infectious Mononucleosis Hepatitis in Young Adults: Two Case Reports

Infectious mononucleosis due to Epstein-Barr virus (EBV) infection sometimes causes acute hepatitis, which is usually self-limiting with mildly elevated transaminases, but rarely with jaundice. Primary EBV infection in children is usually asymptomatic, but in a small number of healthy individuals, typically young adults, EBV infection results in a clinical syndrome of infectious mononucleosis with hepatitis, with typical symptoms of fever, pharyngitis, lymphadenopathy, and hepatosplenomegaly. EBV is rather uncommonly confirmed as an etiologic agent of acute hepatitis in adults. Here, we report two cases: the first case with acute hepatitis secondary to infectious mononucleosis and a second case, with acute hepatitis secondary to infectious mononucleosis concomitantly infected with hepatitis A. Both cases involved young adults presenting with fever, pharyngitis, lymphadenopathy, hepatosplenomegaly, and atypical lymphocytosis confirmed by serologic tests, liver biopsy and electron microscopic study