Design, Simulation and Fabrication of Insulated Gate Bipolar Transistors (IGBT)

This project serves as a study to determine the feasibility of the current CMOS toolsets and processes available at Semiconductor & Microsystems Fabrication Laboratory (SMFL) for the fabrication of whole wafer power devices. Several designs and devices were explored. The Insulated Gate Bipolar Transistor (~LGBT) is a device widely used for high power electronic applications and was selected for this study. This device has bipolar current flow and a MOS gate thus combining advantages of both the Double diffused MOS (DMOS) and Power Bipolar junction transistor. Prototypes consisting of transistors with varying densities, gate lengths and gate widths were fabricated to characterize these devices Attempts were made to study the effect of field oxide thickness on breakdown voltage. Photomask were designed in mentor graphics. Process was designed to obtain required power rating. The desIgn was simulated in ATHENA to verify the process conditions. The IGBTs were fabricated as per the design on standard 4” high resistivity n-type wafers. 8 device wafers and 4 control wafers were used for the process, which involved 4 mask levels. Two additional wafers were processed with this lot to obtain DMOS. The fabricated devices were tested to determine electrical characteristics. The IV characteristics obtained for both the DMOS and IGBT exhibit field effect. However this field effect is in parallel with a parasitic conductance and limits the transistor from turning off. It is also observed that the devices are operational as depletion mode devices instead of enhancement mode devices. The shortcomings of the current process and device designed have been listed and required modifications have been suggested

Mi-1-mediated resistance to Meloidogyne incognita in tomato may not rely on ethylene but hormone perception through ETR3 participates in limiting nematode infection in a susceptible host.

Root-knot nematodes, Meloidogyne spp., are important pests of tomato (Solanum lycopersicum) and resistance to the three most prevalent species of this genus, including Meloidogyne incognita, is mediated by the Mi-1 gene. Mi-1 encodes a nucleotide binding (NB) leucine-rich repeat (LRR) resistance (R) protein. Ethylene (ET) is required for the resistance mediated by a subset of NB-LRR proteins and its role in Mi-1-mediated nematode resistance has not been characterized. Infection of tomato roots with M. incognita differentially induces ET biosynthetic genes in both compatible and incompatible interactions. Analyzing the expression of members of the ET biosynthetic gene families ACC synthase (ACS) and ACC oxidase (ACO), in both compatible and incompatible interactions, shows differences in amplitude and temporal expression of both ACS and ACO genes in these two interactions. Since ET can promote both resistance and susceptibility against microbial pathogens in tomato, we investigated the role of ET in Mi-1-mediated resistance to M. incognita using both genetic and pharmacological approaches. Impairing ET biosynthesis or perception using virus-induced gene silencing (VIGS), the ET-insensitive Never ripe (Nr) mutant, or 1-methylcyclopropene (MCP) treatment, did not attenuate Mi-1-mediated resistance to M. incognita. However, Nr plants compromised in ET perception showed enhanced susceptibility to M. incognita indicating a role for ETR3 in basal resistance to root-knot nematodes

Update on Membranoproliferative GN

Membranoproliferative GN represents a pattern of injury seen on light microscopy. Historically, findings on electron microscopy have been used to further subclassify this pathologic entity. Recent advances in understanding of the underlying pathobiology have led to a proposed classification scheme based on immunofluorescence findings. Dysregulation of the complement system has been shown to be a major risk factor for the development of a membranoproliferative GN pattern of injury on kidney biopsy. Evaluation and treatment of this complex disorder rest on defining the underlying mechanisms

Intravenous albumin infusion is an effective therapy for hyponatremia in patient with malignant ascites

There are few reports about the treatment of moderate to severe hyponatremia associated with malignant liver metastasis. Here, we report using intravenous salt poor albumin infusion to treat hypervolemic cirrhosis related hyponatremia. A 58-year-old female with ascites secondary to metastatic breast cancer was referred to our department with symptomatic hyponatremia (serum sodium concentration of 121 mEq/L). The serum sodium level was corrected slowly over 2 days with intravenous albumin infusion and the patient\u27s symptoms - fatigue, nausea, dizziness and headache improved