Publicaciones académicas
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Esta colección incluye artículos de profesores de la Pontificia Universidad Católica de Chile, publicados en revistas nacionales y extranjeras.
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Browsing Publicaciones académicas by browse.metadata.categoria "Ciencias de la tierra"
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- Item11 beta-hydroxysteroid dehydrogenase activity in patients with hypertension and low plasma renin activity(2002) Mosso, L; Carvajal, C; Campino, C; Rojas, A; Gonzalez, A; Barraza, A; Montero, J; Fardella, C; NCD Risk Factor Collaboration (NCD-RisC)Background: Half of hypertensive patients with, low plasma renin activity have a primary hyperaldosteronism. Among the remaining half 11beta-hydroxysteroid dehydrogenase type 2 (11betaHSD2) deficiency plays all important role. This enzyme catalyzes the conversion of cortisol to cortisone, avoiding the interaction of cortisol with, the mineralocorticoid receptor. If the enzyme fails, cortisol will stimulate sodium and water reabsorption and increase blood pressure. Aim: To determine biochemical alterations, suggestive of 11betaSHSD2 deficiency, in low-renin hypertensive patients. Patients and Methods: Twenty eight hypertensive patients with a plasma renin activity of less than 0.5 ug/ml/h and with a plasma aldosterone of less than 5 ng/dl were studied. Twenty eight normotensive patients were studied as controls. Serum. cortisol (RIA), cortisone (ELISA) and the serum cortisol/cortisone ratio were determined in all of them, between, 9 and 10 AM. Measurements were confirmed by high pressure liquid chromatography. The serum cortisol/cortisone ratio was considered abnormal when its Ln (cortisol/cortisone) value was over 2 standard deviations of the mean. Results: Serum cortisol was higher in hypertensive subjects than in controls (11.1 +/- 3.3 and 9.2 +/- 2.8 mug/dl, respectively; p <0.05). No differences were observed in serum cortisone (3.4 +/- 1.3 and 3.7 +/- 1.2 μg/dl, respectively). Four hypertensive subjects bad all abnormally high Ln (cortisol/cortisone) value (1.86; 1.73; 2.07 and 2.01, considering a normal value of less than 1.61). Conclusions: Four of 28 hypertensive subjects with, low plasma renin activity and aldosterone had biochemical alterations suggestive of 11.1βHSD2 deficiency.
- Item11β-hydroxysteroid dehydrogenase activity in patients with hypertension and low plasma renin activityActividad de 11 beta hidroxiesteroide dehidrogenasa tipo 2 en hipertensos chilenos(2002) Fardella B C.; Mosso G L.; Carvajal M C.; Campino J C.; Rojas O A.; González P A.; Barraza M A.; Montero L J.; NCD Risk Factor Collaboration (NCD-RisC)Background: Half of hypertensive patients with low plasma renin activity have a primary hyperaldosteronism. Among the remaining half, 11β-hydroxysteroid dehydrogenase type 2 (11βHSD2) deficiency plays an important role. This enzyme catalyzes the conversion of cortisol to cortisone, avoiding the interaction of cortisol with the mineralocorticoid receptor. If the enzyme fails, cortisol will stimulate sodium and water reabsorption and increase blood pressure. Aim: To determine biochemical alterations, suggestive of 11βHSD2 deficiency, in low-renin hypertensive patients. Patients and Methods: Twenty eight hypertensive patients with a plasma renin activity of less than 0.5 ng/ml/h and with a plasma aldosterone of less than 5 ng/dl were studied. Twenty eight normotensive patients were studied as controls. Serum cortisol (RIA), cortisone (ELISA) and the serum cortisol/cortisone ratio were determined in all of them, between 9 and 10 AM. Measurements were confirmed by high pressure liquid chromatography. The serum cortisol/cortisone ratio was considered abnormal when its Ln (cortisol/cortisone) value was over 2 standard deviations of the mean. Results: Serum cortisol was higher in hypertensive subjects than in controls (11.1±3.3 and 9.2±2.8 μg/dl, respectively; p <0.05). No differences were observed in serum cortisone (3.4±1.3 and 3.7±1.2 μg/dl, respectively). Four hypertensive subjects had an abnormally high Ln (cortisol/cortisone) value (1.86; 1.73; 2.07 and 2.01, considering a normal value of less than 1.61). Conclusions: Four of 28 hypertensive subjects with low plasma renin activity and aldosterone had biochemical alterations suggestive of 11βHSD2 deficiency (Rev Méd Chile 2002; 130: 1201-8).
- ItemA 22,000-Year Record of Monsoonal Precipitation from Northern Chile's Atacama Desert(2000) Betancourt, Jl.; Latorre H., Claudio
- ItemA 7000‐year high‐resolution lake sediment record from coastal central Chile (Lago Vichuquén, 34°S): implications for past sea level and environmental variability(2017) Frugone, M. J.; Latorre H., Claudio; Giralt, Santiago; Polanco Martínez, Josué; Bernárdez, Patricia; Oliva Urcía, Belén; Maldonado, Antonio; Carrevedo, María Laura; Moreno, Ana; Delgado Huertas, Antonio; Prego, Ricardo; Barreiro Lostres, Fernando; Valero Garcés, Blas
- ItemA Case Study on Fog/Low Stratus Occurrence at Las Lomitas, Atacama Desert (Chile) as a Water Source for Biological Soil Crusts(2018) Lehnert, Lukas W.; Thies, Boris; Trachte, Katja; Achilles, Sebastian; Osses, Pablo; Baumann, Karen; Schmidt, Jakob; Samolov, Elena; Jung, Patrick; Leinweber, Peter; Karsten, Ulf; Buedel, Burkhard; Bendix, Joerg
- ItemA Functional Loss Assessment of a Hospital System in the Bio-Bio Province(EARTHQUAKE ENGINEERING RESEARCH INST, 2012) Mitrani Reiser, Judith; Llera Martin, Juan Carlos de la; Mahoney, Michael; Holmes, William T.; Bissell, Rick; Kirsch, ThomasThe objectives of this study were to introduce a damage and loss-of-function survey tool that can be used to standardize future assessment of hospital performance, to assess the impact of the 2010 Chilean earthquake on the functions of the public hospital system in the Bio-Bio Province, and to translate these results as lessons that can be applied to U.S. hospitals. This study focused on damage to structural and nonstructural components, utility services, and equipment, as well as loss of supplies and personnel. Structural engineers completed a visual inspection of facilities, and hospital administrators were surveyed to assess the overall impact on operations. All hospitals lost communications, electrical power, and water for several days. All hospitals reported some physical damage although only one suffered significant structural damage. The lessons learned from Chile are applied to U.S. practice of hospital seismic mitigation. [DOI: 10.1193/1.4000044]
- ItemA global comparison of the climatic niches of urban and native tree populations(2018) Kendal, Dave; Dobbs, Cynnamon; Gallagher, R. V.; Beaumont, L. J.; Baumann, J.; Williams, N. S. G.; Livesley, S. J.
- ItemA hydrogeochemistry and isotopic approach for the assessment of surface water-groundwater dynamics in an arid basin : the Limari watershed, North-Central Chile(2015) Oyarzun, Ricardo; Jofre, Elizabeth; Morales, Paulina; Maturana, Hugo; Oyarzun, Jorge; Kretschmer, Nicole; Aguirre, Evelyn; Gallardo, Patricio; Toro, Luis E.; Muñoz Pardo, José Francisco; Aravena, Ramón
- ItemA model-data assessment of the role of Southern Ocean processes in the last glacial termination(2016) Eichinger, Roland; Shaffer, Gary; Albarrán, Nelsón; Maisa Rojas; Lambert, Fabrice
- ItemA new aerobic chemolithoautotrophic arsenic oxidizing microorganism isolated from a high Andean watershed(2018) Anguita, Javiera M.; Rojas, Claudia; Pastén González, Pablo Arturo; Vargas Cucurella, Ignacio Tomás; CEDEUS (Chile)
- ItemA physical model for dynamic analysis of wine barrel stacks(2010) Candia,Gabriel; Llera Martin, Juan Carlos de la; Almazán Campillay, José Luis
- ItemA reanalysis of the Chilean ocean circulation: preliminary results for the region between 20 degrees S to 40 degrees S(2017) Aiken, Christopher Michael
- ItemA review of the bipolar see-saw from synchronized and high resolution ice core water stable isotope records from Greenland and East Antarctica(2015) Landais, A.; Masson Delmotte, V.; Stenni, B.; Selmo, E.; Roche, D. M.; Jouzel, J.; Lambert, Fabrice; Guillevic, M.; Bazin, L.; Arzel, O.; Vinther, B.; Gkinis, V.; Popp, T.
- ItemA simple model for estimating changes in rainfall erosivity caused by variations in rainfall patterns(2018) Lobo, Gabriel P.; Bonilla Meléndez, Carlos Alberto
- ItemA simplified and versatile element model for elastomeric seismic isolation bearings(SAGE PUBLICATIONS INC, 2021) Miranda Camus, Sebastián; Miranda, Eduardo; Llera Martin, Juan Carlos de laA novel approach for two-dimensional modeling of elastomeric bearings using three springs in parallel is presented. This simplified element model considers as follows: (1) an elastoplastic spring with a smooth transition between branches; (2) a linear elastic spring; and (3) a non-linear elastic spring, and is fully defined by only six parameters. The main advantages of the simplified model are twofold: (1) versatility, as a single model is capable of accurately reproducing the main characteristics of the hysteretic behavior of different types of rubber-based seismic isolators, including low damping rubber bearings (LDRBs), high damping rubber bearings (HDRBs), and lead-core rubber bearings (LRBs) and (2) simplicity, as it requires fewer parameters and it is easier to calibrate from experimental cyclic test results than most currently available models. Model parameters' identification is illustrated using quasi-static cyclic and earthquake simulator tests of HDRBs and LRBs, demonstrating that the model shows a good agreement between the test-measured and model-predicted hysteretic behavior. Different objective functions are evaluated in the optimization procedure, and their effect on the identified parameters is studied and discussed. This practitioner-oriented model is particularly amenable for implementation in general-purpose structural analysis software. Its usage is strongly recommended as an initial-stage design tool to select the optimal isolation system for a specific project.
- ItemA simulation of the Chilean Coastal Current and associated topographic upwelling near Valparaiso, Chile(2008) Aiken, Christopher Michael; Castillo Silva, Manuel Ignacio; Navarrete C., Sergio
- ItemA stochastic model of streamflow for urbanized basins(2014) Mejía, A.; Daly, E.; Rossel, F.; Jovanovic, T.; Gironás León, Jorge Alfredo
- ItemA synthesis of ENSO effects on drylands in Australia, North America and South America(2006) Holmgren, M.; Jaksic Andrade, Fabián; Lima Arce, Mauricio
- ItemA(-6)G variant of angiotensinogen gene and aldosterone levels in hypertensives(1999) Fardella, C; Zamorano, P; Mosso, L; Gomez, L; Pinto, M; Soto, J; Oestreicher, E; Cortes, P; Claverie, X; Montero, J; NCD Risk Factor Collaboration (NCD-RisC)Recently, a novel mutation in the promoter region of the angiotensinogen gene that involves the presence of an adenine instead of a guanine 6 bp upstream from the transcription initiation site (A(-6)G) has been shown to induce an increase in gene transcription. The aim of this study was to determine the prevalence of the A(-6)G mutation in essential hypertensive patients and to correlate it with aldosterone and renin activity levels. We studied 191 hypertensives. We measured levels of aldosterone (plasma and urinary) and plasma renin activity. We determined the variants A and G using a mutagenically separated polymerase chain reaction technique. In 191 hypertensives, the A variant was detected in 266 of 382 (69.6%) and the G variant in 116 of 382 alleles (30.4%). Plasma aldosterone was significantly higher in patients homozygous for AA than in those homozygous for GG (369+/-208 versus 246+/-142 pmol/L). Urinary aldosterone was significantly higher in homozygous AA than in AG or GG patients (62.4+/-39.4 versus 50.8+/-25.2 and 37.4+/-22.3 nmol/d, respectively). When the patients were grouped according to the presence or absence of the A allele, the aldosterone levels and the plasma aldosterone/plasma renin activity ratio were significantly higher in patients with the A allele, The presence of the A variant was associated with higher levels of aldosterone. These results suggest that the presence of the A variant could determine the appearance of arterial hypertension through higher transcription activity of the angiotensinogen gene and concomitant aldosterone production.
- ItemAccumulation of impact markers in desert wetlands and implications for the Younger Dryas impact hypothesis(2012) Pigati, J.; Latorre H., Claudio; Martínez Gálvez, Katherine Eliana.