University of Utah

About: University of Utah is a education organization based out in Salt Lake City, Utah, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 52894 authors who have published 124076 publications receiving 5265834 citations. The organization is also known as: The U & The University of Utah.

Polarization Effects in Intermediate Temperature, Anode‐Supported Solid Oxide Fuel Cells

Abstract: Anode-supported sold oxide fuel cells with yttria-stabilized zirconia (YSZ) electrolyte, Sr-doped LaMnO{sub 3} (LSM) + YSZ cathode, and Ni + YSZ anode were fabricated and their performance was evaluated between 650 and 800 C with humidified hydrogen as the fuel and air as the oxidant. Maximum power densities measured were {approximately} 1.8 W/cm{sup 2} at 800 C and {approximately} 0.82 W/cm{sup 2} at 650 C. Voltage (V) vs. current density (i) traces were nonlinear; V vs. i exhibited a concave-up curvature [d{sup 2}V/di{sup 2} {ge} 0] at low values of i and a convex-up curvature [d{sup 2}V/di{sup 2} {le} 0] at higher values of i, typical of many low temperature fuel cells. Analysis of concentration polarization based on transport of gaseous species through porous electrodes, in part, is used to explain nonlinear V vs. i traces. The effects of activation polarization in the Tafel limit are also included. It is shown that in anode-supported cells, the initial concave-up curvature can be due either to activation or concentration polarization, or both. By contrast, in cathode-supported cells, the initial concave-up curvature is entirely due to activation polarization. From the experimentally observed V vs. i traces for anode-supported cells, effective binary diffusivity of more » gaseous species on the anodic side was estimated to be between {approximately} 0.1 cm{sup 2}/s at 650 C and {approximately} 0.2 cm{sup 2}/s at 800 C. The area specific resistance of the cell (ohmic part), varied between {approximately} 0.18 {Omega} cm{sup 2} at 650 C and {approximately} 0.07 {Omega} cm{sup 2} at 800 C with an activation energy of {approximately} 65 kJ/mol. « less

DICER1 deficit induces Alu RNA toxicity in age-related macular degeneration

Abstract: Geographic atrophy (GA), an untreatable advanced form of age-related macular degeneration, results from retinal pigmented epithelium (RPE) cell degeneration. Here we show that the microRNA (miRNA)-processing enzyme DICER1 is reduced in the RPE of humans with GA, and that conditional ablation of Dicer1, but not seven other miRNA-processing enzymes, induces RPE degeneration in mice. DICER1 knockdown induces accumulation of Alu RNA in human RPE cells and Alu-like B1 and B2 RNAs in mouse RPE. Alu RNA is increased in the RPE of humans with GA, and this pathogenic RNA induces human RPE cytotoxicity and RPE degeneration in mice. Antisense oligonucleotides targeting Alu/B1/B2 RNAs prevent DICER1 depletion-induced RPE degeneration despite global miRNA downregulation. DICER1 degrades Alu RNA, and this digested Alu RNA cannot induce RPE degeneration in mice. These findings reveal a miRNA-independent cell survival function for DICER1 involving retrotransposon transcript degradation, show that Alu RNA can directly cause human pathology, and identify new targets for a major cause of blindness.

Hydrogels: swelling, drug loading, and release.

Abstract: Hydrogels have been used by many investigators in controlled-release drug delivery systems because of their good tissue compatibility and easy manipulation of swelling level and, thereby, solute permeability The desired kinetics, duration, and rate of solute release from hydrogels are limited to specific conditions, such as hydrogel properties, amount of incorporated drug, drug solubility, and drug-polymer interactions This review summarizes the compositional and structural effects of polymers on swelling, loading, and release and approaches to characterize solute release behavior in a dynamic state A new approach is introduced to compensate drug effects (solubility and loading) with the release kinetics by varying the structure of heterogeneous polymers Modulated or pulsatile drug delivery using functional hydrogels is a recent trend in hydrogel drug delivery

Explaining the abundance of ants in lowland tropical rainforest canopies.

Abstract: The extraordinary abundance of ants in tropical rainforest canopies has led to speculation that numerous arboreal ant taxa feed principally as “herbivores” of plant and insect exudates. Based on nitrogen (N) isotope ratios of plants, known herbivores, arthropod predators, and ants from Amazonia and Borneo, we find that many arboreal ant species obtain little N through predation and scavenging. Microsymbionts of ants and their hemipteran trophobionts might play key roles in the nutrition of taxa specializing on N-poor exudates. For plants, the combined costs of biotic defenses and herbivory by ants and tended Hemiptera are substantial, and forest losses to insect herbivores vastly exceed current estimates.