Throughput, spectral efficiency and power consumption are the three major factors that drive the evolution of the communication systems. The data rate of modern wireless communication has increased from 10 kb/s (1995 narrow band GSM) to over 100 Mb/s (2015 LTE Advanced) in just twenty years. The data rate of the wired communication has reached more than 2 Gb/s to accommodate the fast growing cellular data rates. The Moore's law is still in effect and the wideband communication era continues to become more entrenched in our daily lives! Dealing with wideband signals poses great challenges to our existing signal processing approaches. At a high sample rate, i.e., GHz level, any non-trivial signal processing, e.g., digital filtering, may saturate the processing resources. This is because the signal's sample rate has become comparable to the hardware's clock rate! At such high rate, significant amount of hardware resources or parallelism is needed to execute the required number of multiply and accumulation operations. This phenomenon is the bottleneck in our further pursuit of higher data rate communication and will raise the hardware cost significantly. This dissertation tackles several challenging wideband signal processing problems in communication system design. In particular, we propose the non-maximally decimated filter bank (NMDFB) based digital filtering approach. A key attribute of this structure is that the filtering is achieved via the intermediated processing element (IPE) embedded in between a pair of analysis and synthesis NMDFB. The polyphase implementation of NMDFB has its workload on the same order as the FFT and is thus extremely efficient. This type of digital filter implementation not only allows the signal processing to be performed at a significantly reduced sampling rate but also exhibits significant savings in power consumption over the conventional approaches. The NMDFB based processing supports many if not all of the commonly used filtering tasks in communications, and therefore can be used to implement a wideband receiver. We demonstrate this by developing a NMDFB based efficient linear / non-linear equalization techniques for single carrier QAM signal. We also address the carrier and symbol timing synchronization problems based on NMDFB approach. Besides the filtering tasks, the NMDFB based architecture also enables several key signal processing tasks required by the future's communication systems. We show NMDFB can be used as the basis of an efficient wideband diversity combiner over frequency selective channels. We also demonstrate advanced channelization technique based on NMDFB. Unlike the existing channelizers that often pose constrains on either signal format or signal spectrum, the proposed channelizer is able to channelize multiple signals with arbitrary center frequency, arbitrary bandwidth and arbitrary format

Traditional Chinese Medicine (TCM) has been developed for thousands of years and has formed an integrated theoretical system based on a large amount of clinical practice. However, essential ingredients in TCM herbs have not been fully identified, and their precise mechanisms and targets are not elucidated. In this study, a new strategy combining comprehensive two-dimensional K562/cell membrane chromatographic system and in silico target identification was established to characterize active components from Indigo naturalis, a famous TCM herb that has been widely used for the treatment of leukemia in China, and their targets. Three active components, indirubin, tryptanthrin and isorhamnetin, were successfully characterized and their anti-leukemia effects were validated by cell viability and cell apoptosis assays. Isorhamnetin, with undefined cancer related targets, was selected for in silico target identification. Proto-oncogene tyrosine-protein kinase (Src) was identified as its membrane target and the dissociation constant (Kd) between Src and isorhamnetin was 3.81 μM. Furthermore, anti-leukemia effects of isorhamnetin were mediated by Src through inducing G2/M cell cycle arrest. The results demonstrated that the integrated strategy could efficiently characterize active components in TCM and their targets, which may bring a new light for a better understanding of the complex mechanism of herbal medicines.

Mitochondrial reactive oxygen species (ROS) are essential regulators of cellular signaling, metabolism and epigenetics underlying the pathophysiology of numerous diseases. Despite the critical function of redox regulation in mitochondria, currently there are limited methods available to monitor protein oxidation in this key subcellular organelle. Here, we describe compounds for imaging sulfenylated proteins in mitochondria: DCP-NEt2-Coumarin (DCP-NEt2C) and rhodamine-based DCP-Rho1. Side-by-side comparison studies are presented on the reactivity of DCP-NEt2C and DCP-Rho1 with a model protein sulfenic acid (AhpC-SOH) and mitochondrial localization to identify optimized experimental conditions for labeling and visualization of protein sulfenylation that would be independent of mitochondria membrane potential and would not impact mitochondrial function. These probes are applied to image mitochondrial protein sulfenylation under conditions of serum starvation and in a cell culture model of lung cancer exposed to ionizing radiation and silver nanoparticles, agents serving dual functions as environmental stressors and cancer therapeutics.