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This work investigates three penalized-likelihood expectation maximization (EM) algorithms for image reconstruction with Poisson data where the images are known a priori to be sparse in the space domain. The penalty functions considered are the 1 norm, the 0 " norm, " and a penalty function based on the sum of logarithms of pixel values, R(x) = np j=1 log(More)
The persistence of central memory CD4(+) T cells (T(CM) cells) is a major correlate of immunological protection in HIV/AIDS, as the rate of T(CM) cell decline predicts HIV disease progression. In this study, we show that T(CM) cells and effector memory CD4(+) T cells (T(EM) cells) from HIV(+) elite controller (EC) subjects are less susceptible to(More)
Chronic viral infections lead to persistent CD8 T cell activation and functional exhaustion. Expression of programmed cell death-1 (PD-1) has been associated to CD8 T cell dysfunction in HIV infection. Herein we report that another negative regulator of T cell activation, CD160, was also upregulated on HIV-specific CD8 T lymphocytes mostly during the(More)
Dengue virus (DENV) is a re-emerging arthropod borne flavivirus that infects more than 300 million people worldwide, leading to 50,000 deaths annually. Because dendritic cells (DC) in the skin and blood are the first target cells for DENV, we sought to investigate the early molecular events involved in the host response to the virus in primary human(More)
—There are many systems for counting photons such as gamma–rays emitted from radioactive sources. Many of these systems are also position–sensitive, which means that the system provides directional information about recorded events. This paper investigates whether or not the additional information provided by position–sensitive capability improves the(More)
BACKGROUND AIMS One important problem commonly encountered after hepatocyte transplantation is the low numbers of transplanted cells found in the graft. If hepatocyte transplantation is to be a viable therapeutic approach, significant liver parenchyma repopulation is required. Mesenchymal stromal cells (MSC) produce high levels of various growth factors,(More)
—Likelihood-based test statistics for the task of detecting a radioactive source in background using a gamma-ray imaging system often have intractable distributions. This complicates the tasks of predicting detection performance and setting thresholds that ensure desired false-alarm rates. Asymptotic distributions of test statistics can aid in predicting(More)
The innate and adaptive immune systems fail to control HCV infection in the majority of infected individuals. HCV is an ssRNA virus, which suggests a role for Toll-like receptors (TLRs) 7 and 8 in initiating the anti-viral response. Here we demonstrate that HCV genomic RNA harbours specific sequences that initiate an anti-HCV immune response through TLR7(More)
Secreted Slit proteins have previously been shown to signal through Roundabout (Robo) receptors to negatively regulate axon guidance and cell migration. During vertebrate development, Slit proteins have also been shown to stimulate branching and elongation of sensory axons and cortical dendrites. In this study, Slit1/Robo2 mRNA and protein expressions were(More)
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