23 research outputs found
Electrochemical Behaviour of Galvanized Steel Embedded in Concrete Exposed to Sand Contaminated with NaCl
This research evaluates the corrosion of reinforced concrete, exposed to marine sand, simulating what happens with the elements of laying of foundations of all concrete structures constructed on coasts of Mexico and the world. In such concrete specimens a steel bar AISI 1018 and Galvanized Steel was embedded as reinforcement, the mixed concrete was of ratio w/c=0.45 (f´c = 350 kg / cm2), according to ACI 211.1, using two type cements CPC 30R and CPC 30R RS. The corrosion rate was evaluated by electrochemical techniques, corrosion potential Ecorr (ASTM C-876-09) and Linear Polarization Resistance (ASTM-G59). These specimens were exposed in a marine sand contaminated with 0, 1, 2 and 3% NaCl, the exposure time was 260 days where, according to the electrochemical results of Ecorr and Icorr, we could determine that the better performance of the specimens was galvanized steel and concrete made with cement CPC 30R RS, this research demonstrated the importance of developing special to elaborated concrete durability in aggressive environment such as is the ground where uproots all reinforced concrete structures
Haemosporidian parasite prevalence, parasitemia, and diversity in three resident bird species at a shrubland dominated landscape of the Mexican highland plateau
Clonal chromosomal mosaicism and loss of chromosome Y in elderly men increase vulnerability for SARS-CoV-2
The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, COVID-19) had an estimated overall case fatality ratio of 1.38% (pre-vaccination), being 53% higher in males and increasing exponentially with age. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, we found 133 cases (1.42%) with detectable clonal mosaicism for chromosome alterations (mCA) and 226 males (5.08%) with acquired loss of chromosome Y (LOY). Individuals with clonal mosaic events (mCA and/or LOY) showed a 54% increase in the risk of COVID-19 lethality. LOY is associated with transcriptomic biomarkers of immune dysfunction, pro-coagulation activity and cardiovascular risk. Interferon-induced genes involved in the initial immune response to SARS-CoV-2 are also down-regulated in LOY. Thus, mCA and LOY underlie at least part of the sex-biased severity and mortality of COVID-19 in aging patients. Given its potential therapeutic and prognostic relevance, evaluation of clonal mosaicism should be implemented as biomarker of COVID-19 severity in elderly people. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, individuals with clonal mosaic events (clonal mosaicism for chromosome alterations and/or loss of chromosome Y) showed an increased risk of COVID-19 lethality
Pseudoaneurismas por drogas intravenosas
Antecedentes: En los pseudoaneurismas infectados de arteria femoral asociados al uso de drogas intravenosas, la ligadura primaria para el tratamiento causa controversia, sin embargo, el territorio comprometido puede continuar irrigado por vías colaterales. Objetivo: Reportar la experiencia del manejo de pseudoaneurismas en un servicio de angiología y cirugía vascular. Métodos: Estudio observacional, descriptivo de una serie de casos. Resultados: Se reportan 15 pacientes, relación hombre: mujer 14:1, promedio de edad de 42 años. Siete (46.6%) con presentación de pseudoaneurisma femoral izquierdo, 5 (33.3%) de ellos con presentación de pseudoaneurisma femoral derecho, 2 (13.3%) con pseudoaneurisma humeral derecho y uno (6.6%) con pseudoaneurisma humeral izquierdo. En 12 se realizó exclusión del pseudoaneurisma con triple ligadura; y 3 pacientes fueron sometidos a revascularización. Conclusiones: En nuestra experiencia, la ligadura primaria sin revascularización tuvo incidencia de amputación baja y supervivencia alta de los pacientes afectados, siendo la claudicación la secuela más frecuente