Rapid optical interrogation of flowing cells or particles is a powerful tool in the field of biomedical diagnostics. Determination of size and composition of fast-flowing cells, with diameters in the range of 2-15 μm, often require complex open-space optics and expensive highspeed cameras. In this work, a method to overcome these challenges by using a hydrodynamic flow-based microfluidic platform coupled with on-chip integrated fiber optics is reported. The lab-scale portable device developed uses a combination of on-chip lensed and nonlensed optical fibers for precision illumination. The narrow light beam produced by the lensed fiber (f ¼ 150 μm) enables precise optical analysis with high sensitivity. A planar arrangement of optical fibers at various angles facilitates multi-parametric analysis from a single point of interrogation. As proof of concept, the laboratory-scale portable bench-top prototype is used to measure fluorescence signals from CD4 immunostained cells and human blood samples. The performance of microfluidic flow analyzer is also compared to the conventional Guava® easyCyte 8HT flow cytometer.

Application profiling-the process of monitoring an application to determine the frequency of execution within specific regions-is an essential step within the design process for many software and hardware systems. Profiling is often a critical step within hardware/software partitioning utilized to determine the critical kernels of an application. In this article, we present an innovative, nonintrusive dynamic application profiler (DAProf) capable of profiling an executing application by monitoring the application's short backward branches, function calls, and function returns. The resulting profile information provides an accurate characterization of the frequently executed loops within the application providing a breakdown of loop executions versus loop iterations per execution. DAProf achieves excellent profiling accuracy with an average accuracy of 98% for loop executions, 97% for average iterations per execution, and 95% for percentage of execution time. In addition, the presented dynamic application profiler incurs as little as 11% area overhead compared to an ARM9 microprocessor. DAProf is ideally suited for rapidly profiling software applications and dynamic optimization approaches such as dynamic hardware/software partitioning in which detailed loop execution information is needed to provide accurate performance estimates.

ABSTRACT

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