Effects of Heat Treatment on the Physicochemical Properties and Electrochemical Behavior of Biochars for Electrocatalyst Support Applications.

The present work reports the synthesis and the physicochemical characterization of biochar from the organic wastes of nopal (Opuntia Leucotricha), coffee grounds (Coffea arabica) and Ataulfo mango seeds (Mangifera indica) as alternative electrocatalyst supports to Vulcan XC-72 carbon black. The biochars were prepared using pyrolysis from organic wastes collected at three temperatures, 600, 750 and 900 °C, under two atmospheres, N2 and H2. The synthesized biochars were characterized using Raman spectroscopy and scanning electron microscopy (SEM) to obtain insights into their chemical structure and morphological nature, respectively, as a function of temperature and pyrolysis atmosphere. A N2 adsorption/desorption technique, two-point conductivity measurements and cyclic voltammetry (CV) were conducted to evaluate the specific surface area (SSA), electrical conductivity and double-layer capacitance, respectively, of all the biochars to estimate their physical properties as a possible alternative carbon support. The results indicated that the mango biochar demonstrated the highest properties among all the biochars, such as an electrical conductivity of 8.3 S/cm-1 at 900 °C in N2, a specific surface area of 829 m2/g at 600 °C in H2 and a capacitance of ~300 mF/g at 900 °C in N2. The nopal and coffee biochars exhibited excellent specific surface areas, up to 767 m2/g at 600 °C in N2 and 699 m2/g at 750 °C in H2, respectively; nonetheless, their electrical conductivity and capacitance were limited. Therefore, the mango biochar at 900 °C in N2 was considered a suitable alternative carbon material for electrocatalyst support. Additionally, it was possible to determine that the electrical conductivity and capacitance increased as a function of the pyrolysis temperature, while the specific surface area decreased for some biochars as the pyrolysis temperature increased. Overall, it is possible to conclude that heat treatment at a high temperature of 900 °C enhanced the biochar properties toward electrocatalyst support applications.

[Characterisation of thromboembolic risk in a mexican population with non-valvular atrial fibrillation and its effect on anticoagulation (MAYA Study)]. / Caracterización del riesgo tromboembólico en una población mexicana con fibrilación auricular (FA) no-valvular y su efecto en la indicación de anticoagulación (estudio MAYA).

OBJECTIVE: To evaluate the risk of stroke and bleeding using the CHA2DS2-VASc and HAS-BLED scores in Mexican patients with atrial fibrillation and to analyze whether the risk score obtained determined treatment decisions regarding antithrombotic therapy. METHODS: This is an observational, retrospective study in Mexican patients recently diagnosed with atrial fibrillation. The risk of stroke was assessed using the CHA2DS2-VASc scores. The bleeding risk was evaluated using the HAS-BLED score. The frequency of use of antithrombotic therapy was calculated according to the results of the score risk assessment. RESULTS: A total of 350 patients with non-valvular atrial fibrillation were analyzed. A 92.9% of patients had a high risk (score ≥ 2) of stroke according to the CHA2DS2-VASc score and only 17.2% were treated with anticoagulants. A high proportion of patients with atrial fibrillation (72.5%) showed both a high risk of stroke and a high risk of bleeding based on HAS-BLED score. CONCLUSIONS: In this group of patients with atrial fibrillation, from Northeast Mexico, there is a remarkably underutilization of anticoagulation despite the high risk of stroke of these patients.

[Heart failure with preserved ejection fraction (HFPEF). Impact of change in the paradigm of isolated diastolic dysfunction]. / Insuficiencia cardiaca con fraccion de expulsion preservada (ICFEP). Impacto del cambio en el paradigma de la disfunción diastólica aislada.

Heart failure with preserved ejection fraction is a significant and growing public health problem, since it currently represents half of all patients with heart failure. Despite improvements in the understanding of the disease, there is no benefit form treatments tested at all. Advances in diagnostic imaging and invasive evaluation algorithms will allow a more accurate and early diagnosis so that treatment of earliest forms in the progression of the disease are applied since the potential for benefit may be higher. Although important progress has been made in our understanding of the pathophysiology, cardiac catheterization, and cellular of diastolic failure mechanisms and not diastolic mechanisms of disease, further research is required promptly to determine how best to address these anomalies to reduce the significant burden of morbidity and mortality in this form of heart failure, which is reaching pandemic proportions.

[Comparative study of overactive bladder prevalence in patients younger than 50 years with and without hyperprolactinemia]. / Estudio comparativo de la prevalencia de vejiga hiperactiva en pacientes menores de 50 años con y sin hiperprolactinemia.

OBJECTIVE: To determine if the hyperprolactinemia is associated with idiopathic overactive bladder. PATIENTS AND METHODS: We performed a transversal and analytic two groups study. We included all the patients whom plasma levels of prolactin were measured in the National Institute of Perinatology from March 1st to May 31, 2005 and fulfilled the selection criteria. To all these patients we applied a questionnaire of eight questions for the overactive bladder diagnostic. We used chi square statistical technique to establish if hyperprolactinemia is associated with the overactive bladder. RESULTS: One hundred sixty years patients were studied, establishing a relative prevalence of 2.82 (IC 95%: 1.45-3.17), determining association between the variables. CONCLUSIONS: hyperprolactinemia is associated with overactive bladder.

[Functional changes in urethra secondary to partum vs cesarean section. Evidence with dynamic perfilometry]. / Cambios funcionales en la uretra secundarios al parto vs cesárea. Demostración con la perfilometría dinámica.

BACKGROUND: The vaginal delivery produces anatomic and functional disease in the pelvic floor. The urethral profilometry, part of urodynamic study, represents graphically the urethral functionality. OBJECTIVE: To determine the functional changes in the dynamic profilometry in women with antecedent of vaginal delivery or cesarean section. PATIENTS AND METHOD: This is a correlation transversal study of 310 urodynamic studies in the Uroginecology Coordination, National Institute of Perinatology at 2003. RESULTS: We found a statistically significant correlation between vaginal delivery and urethral close area and the continence area, determining that a higher number of vaginal deliveries is associated with lower urethral close area and lower continence area.

[Umbilical artery thrombosis. A report of a case and review of the literature]. / Trombosis de la arteria umbilical. Comunicación de un caso y revisión de la bibliografía.

The thrombosis of the umbilical vessels is associated to high prenatal mortality. The arterial occlusion can compromise the maternal-fetal circulation with the neonatal death. Only two cases are reported in the literature with antepartum diagnosis and neonatal survival. We present the case of a 24 years old primigravida patient at 35 weeks normal pregnancy who was admitted in the hospital for diminution of the fetal movement's perception. The diagnosis was made with Doppler ultrasound of umbilical vessels in biophysical fetal evaluation; we decided pregnancy interruption with cesarean surgery. Cesarean delivery produced a male with Apgar scores of 8-9 at 1 and 5 minutes respectively, who was discharged one week later without vital compromise.

[Epidemiology of xanthogranulomatous cholecystitis]. / Epidemiología de la colecistitis xantogranulomatosa.

OBJECTIVE: In order to study patients with a diagnosis of xanthogranulomatous cholecystitis (XGC), we analyzed their demographics, epidemiology and clinical data. MATERIAL AND METHODS: We analyzed the clinical records of XGC during a period of 6 years, obtaining demographic, epidemiologic and clinical data. RESULTS: Of a total of 1425 cholecystectomies performed between January 1991 and December 1996, we found 35 cases of XGC (2.4%). Twenty six (74%) were women (median age: 44 years), 60% were from a low socioeconomic group, 34% has a history of alcoholism and smoking, and 25 patients (71%) had a blood type of O positive. Thirteen patients (37%) presented obstructive jaundice, 11 had dilatation of the choledocus and were treated with ERCP. Of the 35 cholecystectomies, 15 were urgent and 20 elective. Eight were operated laparoscopically and two were converted because of firm adhesions. We had 5 transoperative complications. DISCUSSION: Pre-operative XGC diagnosis is difficult, often mistaken for gall bladder cancer. The incidence in our study (2.4%) is higher than reports in industrialized countries (0.7-1.8%), with a female predominance. The most frequent clinical presentation is that of chronic cholecystitis, but we found a high percentage of patients with obstructive jaundice. We had 0% mortality and 26% morbidity, and no association was found between XGC and gallbladder cancer.

Niveles de antitrombina III y fibrinógeno en pacientes con fibrilación auricular / Levels of antithrombin III and fibrinogen in patients with auricular fibrilation

Antecedentes: La fibrilación auricular es una arritmia sostenida común en la práctica médica; los pacientes que la padecen presentan alteraciones en el sistema de coagulación, particularmente en niveles de antitrombina III (AT-III) y fibrinógeno. Objetivo: Determinar en pacientes con fibrilación aricular la correlación entre imagen ecocardiográfica, niveles de AT-III y fibrinógeno. Material y métodos: Se registraron los niveles de antitrombina III, fibrinógeno y los resultados del ecocardiograma transesofágico de 47 pacientes con fibrilación auricular que ingresaron al Servicio de Urgencias del Hospital de Cardiología, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social. Se formaron dos grupos: I, 30 pacientes menores de 65 años (63.8 por ciento); II, 17 de 65 años o mayores. Resultados: Presentaron AT-III baja y trombos cuatro pacientes del grupo I (8.5 por ciento) y tres del grupo II (6.4 por ciento); cuatro del grupo II (8.5 por ciento), AT-III dentro de los límites de referencia y trombos. Por t de Student y c2 se obtuvo p < 0.05, y mediante p de Spearman y r de Pearson no se observó correlación estadística entre ecocardiograma y niveles de AT-III y fibrinógeno. El hematócrito en el grupo II se encontró elevado en cinco hombres y 12 mujeres. El aumento en los niveles de fibrinógeno y hematócrito predominó en el género femenino. Conclusiones: En los pacientes estudiados no se observó correlación estadística entre AT-III, fibrinógeno y ecocardiograma transesofágico. Los niveles bajos de la primera no estuvieron asociados con trombosis ni con el contraste espontáneo observado en el ecocardiograma.