Luis Enrique Sepúlveda, coleccionista de imágenes y desencanto

Presentación de los dibujos de Luis Enrique Sepúlveda

Influencia del potencial, concentración y pH en el fosfatizado electroquímico y su capacidad como inhibidor de la corrosión de un acero AISI SAE 1018

47 páginas. Maestría en Ciencias e Ingeniería de Materiales.Se llevó a cabo un estudio del proceso de fosfatizado electroquímico de acero AISI SAE 1018, mediante las técnicas electroquímicas de voltamperometría cíclica (VC) y cronoamperometría (CA). Los estudios se realizaron en una disolución acuosa de H3PO4 concentrado a temperatura ambiente. El análisis de los transitorios potenciostáticos de corriente relacionados con la formación de la película de FePO4 a diferentes potenciales aplicados, se efectuó mediante ajustes no lineales a los datos experimentales, empleando modelos de nucleación y crecimiento descritos por Palomar-Pardavé y col. (J. Solid State Electrochem. 17 (2013) 459-466), esto, permitió obtener información para describir los mecanismos de nucleación y crecimiento de la película de fosfatizado formada. Se determinó que la respuesta cronoamperométrica corresponde a una suma de 4 contribuciones, relacionadas con la adsorción de iones fosfato, disolución de Fe, crecimiento 2D de una película conductora de FePO4(s) y el crecimiento 3D de esta misma película con características menos conductoras. Esto permitió el cálculo de la densidad de carga relacionada con cada contribución. Se evaluó la corrosión de un acero al carbono en un medio de ácido Sulfúrico 1M mediante la técnica de Resistencia a la polarización, encontrando que la velocidad a la corrosión y la morfología de la película formada dependen del potencial aplicado. Posteriormente de acuerdo al diagrama de predominio de especies y los diagramas de Pourbaix, se realizaron estudios del proceso de fosfatizado electroquímico para el mismo acero, mediante técnicas electroquímicas de voltamperometría cíclica (VC) y cronoamperometría (CA). Los estudios se realizaron en una disolución acuosa de H3PO4 3.05 M, pH=4, a temperatura ambiente. Para el análisis de los transitorios potenciostáticos de corriente relacionados con la formación de la película de FePO4 se hicieron variaciones a diferentes potenciales, observando que existe la formación directa de la película de FePO4 sin pasar por otras especies.Consejo Nacional de Ciencia y Tecnología (México)

Evaluation of the Effect of Different Co-Solvent Mixtures on the Supercritical CO2 Extraction of the Phenolic Compounds Present in Moringa oleifera Lam. Leaves

Supercritical fluid extraction (SFE), using CO2, is a novel, sustainable and very efficient technique for the recovery of highly apolar compounds. However, the recovery of phenolic compounds requires the use of different co-solvent combinations such as water and ethanol to enhance the recovery of these compounds through the optimization of a number of variables. In this sense, the effect of pressure (100, 150 and 200 bar), temperature (50, 65 and 80 degrees C), extraction time (30, 60, 90, 120, 150 and 180 min) and the effect of the different percentages of ethanol and water as co-solvents on the composition and phenolic content of moringa leaf extracts were evaluated. Six major flavonoids were identified by ultra-high-performance liquid chromatography coupled to a quadrupole-time-of-flight mass spectrometer (UHPLC-Q-ToF-MS). Pressure and temperature had a significant effect on the phenolic composition of the extracts, as well as on their concentrations. The highest concentration of total flavonoids compounds (TFCs) was obtained by using a mixture of CO2 and water of 50:50 (v/v) at 100 bar, at 65 degrees C after a 120 min extraction time that produced a concentration of 11.66 mg +/- 0.02 mg TFC g(-1) sample, which corresponds to 89.0% of the total flavonoids of the sample, obtained by exhaustive extraction

Optimization of an Ultrasound-Assisted Extraction Method Applied to the Extraction of Flavonoids from Moringa Leaves (Moringa oleifera Lam.)

Interest in phenolic compounds has recently increased due to their potential as antioxidant agents. Moringa leaves (Moringa oleifera) have a high content of phenolic compounds, which presents them as a promising source for the extraction of these compounds. However, it is necessary to use analytical techniques to identify and quantify their actual compound content to determine the quality of the raw material and the potential of the final product. Ultrasound assisted extraction is a green, rapid and environmentally friendly extraction technique that produces high quality extracts from natural products. Hence, the aim of this research is to optimize the variables of the ultrasound-assisted extraction (UAE) process for the extraction of moringa leaves using response surface methodology (RSM) to extract the main flavonoids using methanol as the extraction solvent. A Box-Behnken design (BBD) has been used to evaluate the effect of the ultrasound extraction process variables. Finally, the optimal extraction time in the range between 2 and 30 min was determined. The results revealed that the methanol concentration was the most influential variable. The optimal extraction time was established at 15 min. Six of the main flavonoids were quantified by UHPLC-DAD and identified by UHPLC-QToF-MS. The results confirmed that UAE is an efficient method for the extraction and subsequent analysis and quality control of the flavonoids that can be found in moringa leaves

Estado, violencias y ciudadanía en México. Realidad y teoría, entre lo micro y lo macro

Este libro, en general, es un intento por analizar tres categorías: el Estado, la violencia y la ciudadanía, esperamos contribuir desde los particulares enfoques a la reflexión de un tema muy vigente y lastimoso, al cual ha arribado no sólo México en abstracto, sino también, y principalmente, su realidad institucional, la cual se expresa como cosa cotidiana del mundo de principios del siglo XXI en el que vivimos.Proyecto realizado con financiamiento de la Secretaría de Educación Pública-Subsecretaría de Educación Superior-Dirección General de Educación Superior Universitaria. Número del convenio con la SEP: 2018-15-001-017

Atrasentan and renal events in patients with type 2 diabetes and chronic kidney disease (SONAR): a double-blind, randomised, placebo-controlled trial

Background: Short-term treatment for people with type 2 diabetes using a low dose of the selective endothelin A receptor antagonist atrasentan reduces albuminuria without causing significant sodium retention. We report the long-term effects of treatment with atrasentan on major renal outcomes. Methods: We did this double-blind, randomised, placebo-controlled trial at 689 sites in 41 countries. We enrolled adults aged 18–85 years with type 2 diabetes, estimated glomerular filtration rate (eGFR)25–75 mL/min per 1·73 m 2 of body surface area, and a urine albumin-to-creatinine ratio (UACR)of 300–5000 mg/g who had received maximum labelled or tolerated renin–angiotensin system inhibition for at least 4 weeks. Participants were given atrasentan 0·75 mg orally daily during an enrichment period before random group assignment. Those with a UACR decrease of at least 30% with no substantial fluid retention during the enrichment period (responders)were included in the double-blind treatment period. Responders were randomly assigned to receive either atrasentan 0·75 mg orally daily or placebo. All patients and investigators were masked to treatment assignment. The primary endpoint was a composite of doubling of serum creatinine (sustained for ≥30 days)or end-stage kidney disease (eGFR <15 mL/min per 1·73 m 2 sustained for ≥90 days, chronic dialysis for ≥90 days, kidney transplantation, or death from kidney failure)in the intention-to-treat population of all responders. Safety was assessed in all patients who received at least one dose of their assigned study treatment. The study is registered with ClinicalTrials.gov, number NCT01858532. Findings: Between May 17, 2013, and July 13, 2017, 11 087 patients were screened; 5117 entered the enrichment period, and 4711 completed the enrichment period. Of these, 2648 patients were responders and were randomly assigned to the atrasentan group (n=1325)or placebo group (n=1323). Median follow-up was 2·2 years (IQR 1·4–2·9). 79 (6·0%)of 1325 patients in the atrasentan group and 105 (7·9%)of 1323 in the placebo group had a primary composite renal endpoint event (hazard ratio [HR]0·65 [95% CI 0·49–0·88]; p=0·0047). Fluid retention and anaemia adverse events, which have been previously attributed to endothelin receptor antagonists, were more frequent in the atrasentan group than in the placebo group. Hospital admission for heart failure occurred in 47 (3·5%)of 1325 patients in the atrasentan group and 34 (2·6%)of 1323 patients in the placebo group (HR 1·33 [95% CI 0·85–2·07]; p=0·208). 58 (4·4%)patients in the atrasentan group and 52 (3·9%)in the placebo group died (HR 1·09 [95% CI 0·75–1·59]; p=0·65). Interpretation: Atrasentan reduced the risk of renal events in patients with diabetes and chronic kidney disease who were selected to optimise efficacy and safety. These data support a potential role for selective endothelin receptor antagonists in protecting renal function in patients with type 2 diabetes at high risk of developing end-stage kidney disease. Funding: AbbVie

Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

Summary Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung’s disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung’s disease) from 264 hospitals (89 in high-income countries, 166 in middleincome countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in lowincome countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. Interpretation Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between lowincome, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030

Mortality of emergency abdominal surgery in high-, middle- and low-income countries

Background: Surgical mortality data are collected routinely in high-income countries, yet virtually no low- or middle-income countries have outcome surveillance in place. The aim was prospectively to collect worldwide mortality data following emergency abdominal surgery, comparing findings across countries with a low, middle or high Human Development Index (HDI). Methods: This was a prospective, multicentre, cohort study. Self-selected hospitals performing emergency surgery submitted prespecified data for consecutive patients from at least one 2-week interval during July to December 2014. Postoperative mortality was analysed by hierarchical multivariable logistic regression. Results: Data were obtained for 10 745 patients from 357 centres in 58 countries; 6538 were from high-, 2889 from middle- and 1318 from low-HDI settings. The overall mortality rate was 1⋅6 per cent at 24 h (high 1⋅1 per cent, middle 1⋅9 per cent, low 3⋅4 per cent; P < 0⋅001), increasing to 5⋅4 per cent by 30 days (high 4⋅5 per cent, middle 6⋅0 per cent, low 8⋅6 per cent; P < 0⋅001). Of the 578 patients who died, 404 (69⋅9 per cent) did so between 24 h and 30 days following surgery (high 74⋅2 per cent, middle 68⋅8 per cent, low 60⋅5 per cent). After adjustment, 30-day mortality remained higher in middle-income (odds ratio (OR) 2⋅78, 95 per cent c.i. 1⋅84 to 4⋅20) and low-income (OR 2⋅97, 1⋅84 to 4⋅81) countries. Surgical safety checklist use was less frequent in low- and middle-income countries, but when used was associated with reduced mortality at 30 days. Conclusion: Mortality is three times higher in low- compared with high-HDI countries even when adjusted for prognostic factors. Patient safety factors may have an important role. Registration number: NCT02179112 (http://www.clinicaltrials.gov)

Competencia del desarrollo del pensamiento científico en Ciencias Naturales con énfasis en prevención de accidentes en niños de primaria.

Introducción. Evaluación diagnóstica. Tema 1 ¿Qué significa la competencia para el desarrollo del pensamiento científico en ciencias naturales con énfasis en prevención de accidentes en niños de primaria? Evaluación diagnóstica Objetivos específicos. Contenido. Conclusiones. Evaluación final. Material adicional Tema2 ¿Por qué es relevante que adquiera la competencia para el desarrollo del pensamiento científico en ciencias naturales con énfasis en prevención de accidentes en niños de primariaen mi formación? Evaluación diagnóstica Objetivos específicos. Contenido. Conclusiones. Evaluación final. Material adicional Tema 3 ¿Cómo aprendo la competencia para el desarrollo del pensamiento científico en ciencias naturales con énfasis en prevención de accidentes en niños de primaria? Evaluación diagnóstica Objetivos específicos. Contenido. Conclusiones. Evaluación final. Material adicional Tema 4 ¿Cómo aplico la competencia para el desarrollo del pensamiento científico en ciencias naturales con énfasis en prevención de accidentes en niños de primaria? Evaluación diagnóstica Objetivos específicos. Contenido. Conclusiones. Evaluación final. Material adicional Tema 5 ¿Cómo puedo autoevaluar mi competencia (con miras a un constante crecimiento)? Evaluación diagnóstica Objetivos específicos. Contenido. Conclusiones. Evaluación final. Material adicional Evaluación final. Referencias. Créditos

Evaluación de un Proyecto de inversión de un conjunto de departamentos en la Delegación Miguel Hidalgo

Tesis (Licenciado en Ingeniero Arquitecto), Instituto Politécnico Nacional, Licenciatura, ESIA, Unidad Tecamachalco, 2018, 1 archivo PDF, (185 páginas). tesis.ipn.m