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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Comparator-Based Cyclic Analog-to-Digital Conversion with Error-Trimming

Chang, Li-Shen 11 August 2009 (has links)
This thesis focuses on the analysis theory, circuit design, simulations, and chip measurements of the transfer stage in the continuously error-trimming comparator-based switched-capacitor charge transfer stage in the cyclic redundant-sign-digit (RSD) algorithm. Capacitor mismatching remains an insurmountable factor for switched-capacitor circuit designers. To correct errors which result from the capacitor mismatching, a continuous error-trimming circuit is generalized from a typical CBSC circuit. The analysis theory of the error-trimming operation describes the effects of the error-trimming circuit in the CBSC circuit, as well as the guidelines for trimming. The error-trimming operation is able to tune the gain and virtual condition of the charge transfer stage for canceling the gain and offset errors. The circuit is designed, with the 0.35£gm 2-poly 4-metal TSMC process, in fully integral circuits. The circuit is simulated by a matlab simulator and an online Cadence Spectre simulator, to confirm how the operation works. Finally, chip measurements are recorded for verification and simulation comparisons.
2

Study on Zero-Crossing-Based ADCs for Smart Dust Applications

Khan, Shehryar, Awan, Muhammad Asfandyar January 2011 (has links)
The smart dust concept is a fairly recent phenomenon to engineering. It assumes monitoring of a real natural environment in which motes or smart dust machines swarm in collective and coordinate information among themselves and/or to a backend control platform. In analog mixed signal field work on such devices is gaining momentum such that it is conceived to be one of the emerging fields in technology, and work was only possible once the technology for fabrication touched the nanoscale regions. Smart dust network involves remote devices connected in a hive sensing burst type datum signals from the environment and relaying information amongst themselves in an energy efficient manner to coordinate an appropriate response to a detected stimulus. The project presumed a RF based communication strategy for coordination amongst the devices through a wireless medium. That is less susceptible to stringent requirements of LOS and a base band processing system that comprised of an environment sensor, an AFE module, an ADC, a DSP and a DAC. Essentially a 10 bit, 2 Mega Hertz MHz pipelined ADC implemented in a STM 65nm technology. The ADC benefits the smart dust device in allowing it to process data in an energy efficient way and also focusing on reduced complexity as itsdesign feature. While it differs in the other ADC of the system by operating at a higher frequency and assuming a different design philosophy assuming a coherent system sensitive to a clock. The thesis work assumes that various features ofenergy harvesting, regulation and power management present in the smart dustmote would enable the system to contain such a diverse ADC. The ADCs output digital datum would be compatible to the rest of the design modules consisting mainly of DSP sections. The ADC novelty is based on the fact that it removes the necessity of employing a high power consuming OpAmp whose design parameters become more complex as technology scales to the nanoscale era and further down. A systematic, bottom up, test driven approach to design is utilized and various behaviours of the system are captured in Cadence design environment with verilogto layout models and MATLAB and Simulink models.
3

Investigation of a Novel Formulation from Umbilical Cord Blood Stem Cell-Derived Exosomes and Antioxidant (Selenium) in Malignant Melanoma Cells

Altobalani, Tahera S.H.M. January 2023 (has links)
Introduction: Malignant Melanoma (MM), caused by UV radiation-induced DNA damage, is the most invasive form of skin cancer and has an increasing incidence worldwide. The hallmarks of MM include the presence of reactive oxygen species (ROS) and excessive proliferation of tumour cells. Many treatments are available or under investigation as anticancer therapeutics such as cell therapy, immunotherapy, gene therapy and nanotechnology-based strategies but they all have severe complications and side effects that limit their wider use. Methods: The present in vitro study has evaluated the genotoxic and cytotoxic effects of Se and CBSC-derived exosomes, individually and in combination, on lymphocytes from MM patients and healthy controls, and on the CHL-1 melanoma cell line. The comet assay and cell counting kit-8 (CCK-8) assay were used to measure genotoxicity and cytotoxicity, respectively, in all cell types. Molecular mechanisms underlying the observed effects were explored using transcriptional and protein expression profiling of key cell cycle and apoptosis genes, by employing the RT qPCR and Western blotting techniques. Conclusion: Selenium displays antioxidant and genoprotective effects in human lymphocytes, especially in MM patients. Both Se (10 μM) and CBSC-derived exosomes (120 μL) are well tolerated in lymphocytes, but show significant genotoxicity and cytotoxicity towards the CHL-1 cell line, with combined administration exhibiting a synergistic effect.

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