312 research outputs found
MECHANISMS OF DISEASE Acute Oxygen-Sensing Mechanisms
JOSEPH PRIESTLEY, ONE OF THE THREE SCIENTISTS CREDITED WITH THE discovery of oxygen, described the death of mice that were deprived of oxygen. However, he was also well aware of the toxicity of too much oxygen, stating, “For as a candle burns much faster in dephlogisticated [oxygen enriched] than in common air, so we might live out too fast, and the animal powers be too soon exhausted in this pure kind of air. A moralist, at least, may
say, that the air which nature has provided for us is as good as we deserve.”1
In this review we examine the remarkable mechanisms by which different organs detect and respond to acute changes in oxygen tension. Specialized tissues that sense the local oxygen tension include glomus cells of the carotid body, neuroepithelial bodies in the lungs, chromaffin cells of the fetal adrenal medulla, and smooth-muscle cells of the resistance pulmonary arteries,
fetoplacental arteries, systemic arteries, and the ductus arteriosus. Together, they constitute a specialized homeostatic oxygen-sensing system. Although all tissues are sensitive to severe hypoxia, these specialized tissues respond rapidly to moderate changes in oxygen tension within the physiologic range (roughly 40 to 100 mm Hg in an adult and 20 to 40 mm Hg in a fetus)Junta de Andalucí
Forging a new path : a contemporary Pentecostal hermeneutical strategy for the 21st century
The purpose of this thesis is to present a critically informed contemporary Pentecostal hermeneutical strategy that is rooted in Pentecostal identity, in its stories, beliefs and practices. The contemporary hermeneutical strategy is anchored in the Pentecostal community's identity while simultaneously being a critical hermeneutical strategy for the interpretation of Scripture in the production of a praxis-oriented theology. The contemporary strategy recognizes the combined contributions of the Spirit, Scripture, and community in a dialogical interdependent interpretive process. The central theme of the strategy is narrative which is explored in relation to community identity and in relation to biblical interpretation. Pentecostalism was a paramodern movement. The interpretive method of early Pentecostals testifies to this reality. As Pentecostals entered academic communities, their interpretive method became both mainstream and modernistic through the adaptation of the historical critical method(s). The proposed hermeneutical strategy will desire to move beyond the impasse created by Modernity and push Pentecostals into the contemporary context by critically reappropriating early Pentecostal ethos and interpretive practices for a contemporary Pentecostal community
Reapportionment, Regional Politics and Partisan Gains
Geographers and demographers have been analyzing U.S. regional population change for decades. From the perspective of politics and governance, understanding these population changes over time is very important because seats in the House of Representatives are reapportioned every decade in accordance with the U.S. Constitution. Representation in the House, in turn, affects the distribution of votes in the Electoral College and thus the impact of regional population change affects the presidency as well as the Congress. As political geographers we have studied the possible impacts of this population change on elections, issues in Congress and the nation, and if a particular political party has gained or lost in the process. This article is adapted from our recently published co-edited book, Atlas of the 2012 Elections, which examines both short-term and long-term state and regional gains and losses in the House of Representatives and Electoral College to see how the Democrats and Republicans have fared
Holocene Settlement History of the Dundas Islands Archipelago, Northern British Columbia
As this article demonstrates, the Dundas Islands have been home to humans for at least eleven thousand years. This occupation was at times very extensive; this relatively small group of islands was likely home to a population of several thousand people by about two thousand years ago. While geographically on the “outer shores” of Northern Tsimshian traditional territory, these islands were in no way marginal as locations for settlement. We outline the settlement history of the archipelago by presenting the results of the Dundas Islands Archaeological Project, including the radiocarbon dating program results combined with data from three previous small-scale surveys (Archer 2000; Haggarty 1988; Inglis 1975). We discuss different types of habitation sites and chronological trends in their occupation to argue that the Dundas Islands have been near-continuously occupied for at least the entire Holocene and that this was central, not peripheral, to the broader history of human occupation in the region
The glomerulopathy of sickle cell disease
Sickle cell disease (SCD) produces many structural and functional abnormalities in the kidney, including glomerular abnormalities. Albuminuria is the most common manifestation of glomerular damage, with a prevalence between 26 and 68% in adult patients. The pathophysiology of albuminuria in SCD is likely multifactorial, with contributions from hyperfiltration, glomerular hypertension, ischemia-reperfusion injury, oxidative stress, decreased nitric oxide (NO) bioavailability, and endothelial dysfunction. Although its natural history in SCD remains inadequately defined, albuminuria is associated with increased echocardiography-derived tricuspid regurgitant jet velocity, systemic blood pressure, and hypertension, as well as history of stroke, suggesting a shared vasculopathic pathophysiology. While most patients with albuminuria are treated with angiotensin converting enzyme inhibitors/angiotensin receptor blockers, there are no published long-term data on the efficacy of these agents. With the improved patient survival following kidney transplantation, SCD patients with end-stage renal disease should be considered for this treatment modality. Given the high prevalence of albuminuria and its association with multiple SCD-related clinical complications, additional studies are needed to answer several clinically important questions in a bid to adequately elucidate its pathophysiology, natural history, and treatment
Biomass round bales infield aggregation logistics scenarios
Biomass bales often need to be aggregated (collected into groups and transported) to a field-edge stack or a temporary storage before utilization. Several logistics scenarios for aggregation involving equipment and aggregation strategies were modeled and evaluated. Cumulative Euclidean distance criteria evaluated the various aggregation scenarios. Application of a single-bale loader that aggregated bales individually was considered as the “control” scenario with which others were compared. A computer simulation program developed determined bale coordinates in ideal and random layouts that evaluated aggregation scenarios. Simulation results exhibited a “diamond pattern” of bales on ideal layout and a “random pattern” emerged when ≥ 10% variation was introduced. Statistical analysis revealed that the effect of field shape, swath width, biomass yield, and randomness on bale layout did not affect aggregation logistics, while area and number of bales handled had significant effects. Number of bales handled in the direct method significantly influenced the efficiency. Self-loading bale picker with minimum distance path (MDP, 80%) and parallel transport of loader and truck with MDP (78%) were ranked the highest, and single-bale central grouping the lowest (29%) among 19 methods studied. The MDP was found significantly more efficient (4%-16%) than the baler path. Simplistic methods, namely a direct triple-bale loader with MDP (64%-66%), or a loader and truck handling six bales running parallel with MDP (75%-82%) were highly efficient. Great savings on cumulative distances that directly influence time, fuel, and cost were realized when the number of bales handled was increased or additional equipment was utilized
Reduced Expression of Inflammatory Genes in Deceased Donor Kidneys Undergoing Pulsatile Pump Preservation
Background
The use of expanded criteria donor kidneys (ECD) had been associated with worse outcomes. Whole gene expression of pre-implantation allograft biopsies from deceased donor kidneys (DDKs) was evaluated to compare the effect of pulsatile pump preservation (PPP) vs. cold storage preservation (CSP) on standard and ECD kidneys. Methodology/Principal Findings
99 pre-implantation DDK biopsies were studied using gene expression with GeneChips. Kidneys transplant recipients were followed post transplantation for 35.8 months (range = 24–62). The PPP group included 60 biopsies (cold ischemia time (CIT) = 1,367+/−509 minutes) and the CSP group included 39 biopsies (CIT = 1,022+/−485 minutes) (P Conclusions/Significance
Inflammation was the most important up-regulated pattern associated with pre-implantation biopsies undergoing CSP even when the PPP group has a larger number of ECD kidneys. No significant difference was observed in delayed graft function incidence and graft function post-transplantation. These findings support the use of PPP in ECD donor kidneys
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