Analysis and design of reliable mixed-signal CMOS circuits

Facing the constantly increasing reliability challenges under technology scaling, the topics in IC reliability technique have been receiving serious attention during recent years. In this work, based on the understanding of existing physical failure models that have been concentrating on the pre-fab circuits, a set of revised models for major failure mechanisms such as electromigration, hot-carrier, and gate oxide wear-out are created. Besides the modeling of degradation behaviors for circuits in design phase, these models tend to deal with the post-fab device characteristics with the presence of physical defects. In addition, the simulation work has been taken from device level to circuit level hierarchically, presenting the evaluation of circuit level reliability such as degradations of circuit level specs and circuit lifetime prediction. For post-fab ICs under electromigration, the expected circuit lifetime is calculated based on statistical processes and the probability theory. By incorporating all physics-of-failure models and applying circuit level simulation approaches, an IC reliability simulator called ARET (ASIC reliability evaluation tool) has been developed. Besides the reliability evaluation, the reliability hotspot identification function is developed in ARET, which is a key step for conducting IC local design-for-reliability approaches. ARET has been calibrated with a series of stress tests conducted at The Boeing Company. Design-for-reliability (DFR) is a very immature technical area, which has been becoming critical with the continuously shrinking reliability safety margin. A novel concept, local design-for-reliability is proposed in this work. This DFR technique is closely based on reliability simulation and hotspot identification. By redesigning the circuit locally around reliability hotspots, this DFR approach offers the overall reliability improvement with the maintained circuit performance. Various DFR algorithms are developed for different circuit situations. The experiments on designed and benchmark circuits have shown that significant circuit reliability improvements can be obtained without compromising performance by applying these DFR algorithms.Ph.D.Committee Chair: Chatterjee, Abhijit; Committee Member: Keezer, David; Committee Member: May, Gary; Committee Member: Singh, Adit; Committee Member: Swaminathan, Madhava

IL-10 family cytokines in chronic rhinosinusitis with nasal polyps: From experiments to the clinic

Chronic rhinosinusitis with nasal polyps (CRSwNP) is considered a nasal sinus inflammatory disease that can be dominated by immune cells and cytokines. IL-10 family cytokines exert essential functions in immune responses during infection and inflammation. Recently, the understanding of the roles of the IL-10 family in CRSwNP is being reconsidered. IL-10 family members are now considered complex cytokines that are capable of affecting epithelial function and involved in allergies and infections. Furthermore, the IL-10 family responds to glucocorticoid treatment, and there have been clinical trials of therapies manipulating these cytokines to remedy airway inflammatory diseases. Here, we summarize the recent progress in the understanding of IL-10 family cytokines in CRSwNP and suggest more specific strategies to exploit these cytokines for the effective treatment of CRSwNP.</jats:p

Presence or absence of choroidal hyper-transmission by SD-OCT imaging distinguishes inflammatory from neovascular lesions in myopic eyes

To compare the characteristics of choroidal transmission in punctate inner choroidopathy (PIC) with or without choroidal neovascularization (CNV) and myopic CNV (mCNV) using spectral domain optical coherence tomography (SD-OCT). This retrospective observational case series includes 22 consecutive myopic patients (22 eyes) recruited from April 2016 until April 2018 who complained of acute blurring of vision and showed evidence of hyper-reflective material on SD-OCT imaging. Each patient underwent a comprehensive eye examination and imaging with fundus fluorescein angiography (FFA), SD-OCT, and SD-OCT angiography (SD-OCTA). Based on the results of SD-OCTA imaging and the color fundus imaging, the patients were divided into 2 groups: a group with myopic choroidal neovascularization (mCNV group, n = 10 eyes) and a group with PIC and no evidence of CNV at baseline (PIC group, n = 12 eyes). Four eyes diagnosed with PIC developed secondary PIC-CNV during follow-up. The characteristics of choroidal transmission in these eyes using SD-OCT imaging were compared. At baseline, none of the PIC lesions showed any evidence of blood flow within the lesions on OCTA imaging. However, all of the eyes with mCNV showed flow signals within the subretinal neovascularization on SD-OCTA and subretinal or intra-retinal fluid on SD-OCT imaging. These eyes with mCNV showed subretinal hyper-reflectivity associated with choroidal hypo-transmission accompanied by retinal pigment epithelium (RPE) and ellipsoid zone (EZ) disruption. In eyes with PIC inflammatory lesions, disruption of both the RPE and EZ were observed in 33% of the inflammatory lesions, and disruption of the EZ alone was observed in 67% of the lesions at the baseline. They all showed a hyper-reflective subretinal lesion located above RPE. Three cases (25%) showed evidence of choroidal hyper-transmission at the baseline, while the remaining had normal transmission within the first month after onset. Hyper-transmission then developed in all the lesions as the disease progressed. Four cases of PIC (33%) developed PIC-related CNV that showed choroidal hypo-transmission along with hyper-transmission with disruption of the RPE and EZ. In cases with PIC-related CNV, evidences of neovascularization on SD-OCTA imaging were all detected afterwards. No intra-retinal fluid was detected before secondary CNV occurred. SD-OCT imaging can noninvasively differentiate and track the progression of inflammatory lesions and myopic CNV by using the presence of choroidal hyper-transmission as a sign of just an inflammatory lesion and the presence hypo-transmission as a sign of a secondary CNV, which provides a convenient strategy for diagnosis and treatment of these lesions