10 research outputs found
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Reactive Multiphase Behavior of Co{sub 2} in Saline Aquifers Beneath the Colorado Plateau
Soil gas surveys have been carried out on the Colorado Plateau over areas with natural occurrences of CO{sub 2}. At Farnham Dome, Utah, and Springerville-St. Johns, Arizona, proven CO{sub 2} reservoirs occur at 600-800 m depth, but no anomalous soil gas CO{sub 2} flux was detected. Background CO{sub 2} fluxes of up to about 5 g m{sup -2} day{sup -1} were common in arid, poorly vegetated areas, and fluxes up to about 20 g m{sup -2} day{sup -1} were found at Springerville-St. Johns in heavily vegetated, wet ground adjacent to springs. These elevated fluxes are attributed to shallow root zone activity rather than to a deep upflow of CO{sub 2}. Localized areas of anomalously high CO{sub 2} gas flux ({approx} 100 g m{sup -2} day{sup -1}) were documented along the Little Grand Wash Fault Zone near Crystal Geyser, Utah and nearby in Ten Mile Graben, but those in Ten Mile Graben are not directly associated with the major faults. In both areas, features with a visible gas flux are present. Isotopic measurements on the CO{sub 2} gas confirm that it originated at depth. Evidence of widespread vein calcite at the surface at Farnham Dome and travertine deposits in the other areas suggests that there has been an outflow of CO{sub 2}-rich fluids in the past. 14C ages of pollen trapped in the travertine at Springerville-St. Johns record a period of CO{sub 2} leakage to the atmosphere between 887 {+-} 35 and 3219 {+-} 30 years BP. No travertine deposits appear to be currently forming. At Springerville-St. Johns, Crystal Geyser and Ten Mile Graben, there are significant outflows of high-bicarbonate water. Movement of CO{sub 2}-rich groundwaters may be the dominant mechanism controlling the mobility of CO{sub 2} today. The very localized nature of the soil gas anomalies, evidence of large scale discharge of CO{sub 2} over a very short period of time and the outflow of ground water containing dissolved CO{sub 2} will present challenges for effective, long term monitoring of CO{sub 2} leakage
The n-SET Domain of Set1 Regulates H2B Ubiquitylation-Dependent H3K4 Methylation
Past studies have documented a crosstalk between H2B ubiquitylation (H2Bub) and H3K4 methylation, but little (if any) direct evidence exists explaining the mechanism underlying H2Bub-dependent H3K4 methylation on chromatin templates. Here, we took advantage of an in vitro histone methyltransferase assay employing a reconstituted yeast Set1 complex (ySet1C) and a recombinant chromatin template containing fully ubiquitylated H2B to gain valuable insights. Combined with genetic analyses, we demonstrate that the n-SET domain within Set1, but not Swd2, is essential for H2Bub-dependent H3K4 methylation. Spp1, a homolog of human CFP1, is conditionally involved in this crosstalk. Our findings extend to the human Set1 complex, underscoring the conserved nature of this disease-relevant crosstalk pathway. As not all members of the H3K4 methyltransferase family contain n-SET domains, our studies draw attention to the n-SET domain as a predictor of an H2B ubiquitylation-sensing mechanism that leads to downstream H3K4 methylation
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A reservoir management plan
There are numerous documented cases of extraction of fluids from the ground causing surface subsidence. The cases include groundwater, oil and gas, as well as geothermal fluid withdrawal. A recent comprehensive review of all types of man-induced land subsidence was published by the Geological Survey of America. At the early stages of a geothermal power development project it is standard practice in most countries for an environmental impact report to be required. The possibility of geothermal subsidence has to be addressed, and usually it falls on the geophysicists and/or geologists to make some predictions. The advice given is vital for planning the power plant location and the borefield pipe and drain layout. It is not so much the vertical settlement that occurs with subsidence but the accompanying horizontal ground strains that can do the most damage to any man-made structure
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Reactive Multiphase Behavior of Co{sub 2} in Saline Aquifers Beneath the Colorado Plateau
Field and laboratory investigations of naturally occurring CO{sub 2}-reservoirs are being conducted to determine the characteristics of potential seal and reservoir units and the extent of the interactions that occur between the host rocks and the CO{sub 2} charged fluids. Efforts have focused on the Farnham Dome, located in central Utah, and the Springer-St. Johns field in Arizona and New Mexico. The Springer-St. Johns field is particularly significant because of the presence of extensive travertine deposits that document release of CO{sub 2} to the atmosphere. CO{sub 2} accumulations at both fields occur in sedimentary rocks typical of CO{sub 2} reservoirs occurring on the Colorado Plateau. The main achievements were: (1) to assess the possibility of CO{sub 2} leakage from the Farnham Dome of central Utah; and (2) prepare a paper for presentation at the 3rd Annual Conference on Carbon Sequestration
Bi-allelic <em>LETM1</em> variants perturb mitochondrial ion homeostasis leading to a clinical spectrum with predominant nervous system involvement.
Leucine zipper-EF-hand containing transmembrane protein 1 (LETM1) encodes an inner mitochondrial membrane protein with an osmoregulatory function controlling mitochondrial volume and ion homeostasis. The putative association of LETM1 with a human disease was initially suggested in Wolf-Hirschhorn syndrome, a disorder that results from de novo monoallelic deletion of chromosome 4p16.3, a region encompassing LETM1. Utilizing exome sequencing and international gene-matching efforts, we have identified 18 affected individuals from 11 unrelated families harboring ultra-rare bi-allelic missense and loss-of-function LETM1 variants and clinical presentations highly suggestive of mitochondrial disease. These manifested as a spectrum of predominantly infantile-onset (14/18, 78%) and variably progressive neurological, metabolic, and dysmorphic symptoms, plus multiple organ dysfunction associated with neurodegeneration. The common features included respiratory chain complex deficiencies (100%), global developmental delay (94%), optic atrophy (83%), sensorineural hearing loss (78%), and cerebellar ataxia (78%) followed by epilepsy (67%), spasticity (53%), and myopathy (50%). Other features included bilateral cataracts (42%), cardiomyopathy (36%), and diabetes (27%). To better understand the pathogenic mechanism of the identified LETM1 variants, we performed biochemical and morphological studies on mitochondrial K+/H+ exchange activity, proteins, and shape in proband-derived fibroblasts and muscles and in Saccharomyces cerevisiae, which is an important model organism for mitochondrial osmotic regulation. Our results demonstrate that bi-allelic LETM1 variants are associated with defective mitochondrial K+ efflux, swollen mitochondrial matrix structures, and loss of important mitochondrial oxidative phosphorylation protein components, thus highlighting the implication of perturbed mitochondrial osmoregulation caused by LETM1 variants in neurological and mitochondrial pathologies