Albert Hsiao

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MOTIVATION Microarrays are becoming an increasingly common tool for observing changes in gene expression over a large cross section of the genome. This experimental tool is particularly valuable for understanding the genome-wide changes in gene transcription in response to thiazolidinedione (TZD) treatment. The TZD class of drugs is known to improve(More)
Microarrays are invaluable high-throughput tools used to snapshot the gene expression profiles of cells and tissues. Among the most basic and fundamental questions asked of microarray data is whether individual genes are significantly activated or repressed by a particular stimulus. We have previously presented two Bayesian statistical methods for this(More)
Purpose: 4D flow MRI has the potential to provide global quantification of cardiac flow [1], yet often suffers from low velocity-to-noise ratio. Since blood flow is incompressible, it is approximately divergence-free (div-free). Therefore, most of the divergence components in the flow field originate from noise, which can be reduced by enforcing the(More)
PURPOSE To investigate four-dimensional flow denoising using the divergence-free wavelet (DFW) transform and compare its performance with existing techniques. THEORY AND METHODS DFW is a vector-wavelet that provides a sparse representation of flow in a generally divergence-free field and can be used to enforce "soft" divergence-free conditions when(More)
With improvements in surgical and medical management, patients with congenital heart disease (CHD) are often living well into adulthood. MRI provides critical data for diagnosis and monitoring of these patients, yielding information on cardiac anatomy, blood flow, and cardiac function. Though historically these exams have been complex and lengthy,(More)
TARGET AUDIENCES: Those who are interested in phase regularized reconstruction of MR flow data. PURPOSE: Time-resolved 3D phase-contrast MRI (4D flow) [1] has the potential to provide comprehensive cardiac flow quantification, yet suffers from long acquisition time and phase errors. Compressed sensing (CS) offers an effective way of speeding up scan time by(More)
The hemodynamic and geometric factors leading to propagation of acute Type B dissections are poorly understood. The objective is to elucidate whether geometric and hemodynamic parameters increase the predilection for aortic dissection propagation. A pulse duplicator set-up was used on porcine aorta with a single entry tear. Mean pressures of 100 and 180(More)
Conventional statistical methods for interpreting microarray data require large numbers of replicates in order to provide sufficient levels of sensitivity. We recently described a method for identifying differentially-expressed genes in one-channel microarray data 1. Based on the idea that the variance structure of microarray data can itself be a reliable(More)