Stabilizing Ti3C2Tx MXene flakes in air by removing confined water.

MXenes have demonstrated potential for various applications owing to their tunable surface chemistry and metallic conductivity. However, high temperatures can accelerate MXene film oxidation in air. Understanding the mechanisms of MXene oxidation at elevated temperatures, which is still limited, is critical in improving their thermal stability for high-temperature applications. Here, we demonstrate that Ti[Formula: see text]C[Formula: see text]T[Formula: see text] MXene monoflakes have exceptional thermal stability at temperatures up to 600[Formula: see text]C in air, while multiflakes readily oxidize in air at 300[Formula: see text]C. Density functional theory calculations indicate that confined water between Ti[Formula: see text]C[Formula: see text]T[Formula: see text] flakes has higher removal energy than surface water and can thus persist to higher temperatures, leading to oxidation. We demonstrate that the amount of confined water correlates with the degree of oxidation in stacked flakes. Confined water can be fully removed by vacuum annealing Ti[Formula: see text]C[Formula: see text]T[Formula: see text] films at 600[Formula: see text]C, resulting in substantial stability improvement in multiflake films (can withstand 600[Formula: see text]C in air). These findings provide fundamental insights into the kinetics of confined water and its role in Ti[Formula: see text]C[Formula: see text]T[Formula: see text] oxidation. This work enables the use of stable monoflake MXenes in high-temperature applications and provides guidelines for proper vacuum annealing of multiflake films to enhance their stability.

Antojos y aversiones alimentarias en gestantes del Conurbano Bonaerense, Argentina / Food cravings and aversions in pregnant women in the Buenos Aires Conurban, Argentina

Resumen Introducción : Las gestantes suelen experimentar aversiones y antojos alimentarios, de los cuales se cono cen poco sus características y consecuencias. El objetivo fue conocer la prevalencia de los antojos y aversiones alimentarias, las características del patrón de alimentos que son antojados o evitados y los motivos que subyacen ante su presencia. Métodos : Estudio observacional, descriptivo y trans versal. Un cuestionario validado se aplicó a 370 embara zadas y puérperas en hospitales públicos. Las variables maternas y neonatales se midieron con estadísticas descriptivas y se identificaron aquellas asociadas a los fenómenos en estudio empleando modelos de regresión logística y un análisis por clusters utilizando la técnica multivariante. Resultados : Se detectó una presencia de antojos del 71 al 80% y de aversiones del 55 al 65%. Los alimentos más antojados fueron las frutas y los alimentos dulces y los mayormente rechazados las carnes y el mate. Las características maternas predictoras de antojos fueron: tener menor edad (OR 0.94), vómitos (OR 2.23), y el haber ganado más peso de lo esperado se asoció ne gativamente con la presencia de antojos (OR 0.44). Las variables asociadas a las aversiones fueron la ausencia de antecedentes de hipertensión (OR 0.13), antecedentes de macrosomía (OR 2.70), náuseas (OR 1.86) y complica ciones durante el embarazo (OR 2.23). Discusión : Este trabajó permitió caracterizar los an tojos y aversiones alimentarias durante el embarazo y conocer su elevada frecuencia.

Abstract Introduction : Pregnant women often experience food aversions and cravings, of which little is known about their characteristics and consequences. The objective was to know the prevalence of food cravings and aver sions, the characteristics of the pattern of foods that are craved or avoided, and the reasons behind their presence. Methods : Observational, descriptive and cross-sec tional study. A validated questionnaire was applied to 370 pregnant and postpartum women in public hospi tals. Maternal and neonatal variables were measured with descriptive statistics and those associated with the phenomena under study were identified using logistic regression models and cluster analysis using the mul tivariate technique. Results : A presence of cravings from 71 to 80% and aversions from 55 to 65% was detected. The most craved foods were fruits and sweet foods and the most avoided meats and mate. The maternal characteristics predictive of cravings were: being younger (OR 0.94), vomiting (OR 2.23), and having gained more weight than expected were negatively associated with the presence of cravings (OR 0.44). The variables associated with the aversions were the absence of a history of hypertension (OR 0.13), a history of macrosomia (OR 2.70), nausea (OR 1.86) and complications during pregnancy (OR 2.23). Discussion : This work allowed to characterize food cravings and aversions during pregnancy and to know their high frequency.

[Food cravings and aversions in pregnant women in the Buenos Aires Conurban, Argentina]. / Antojos y aversiones alimentarias en gestantes del Conurbano Bonaerense, Argentina.

INTRODUCTION: Pregnant women often experience food aversions and cravings, of which little is known about their characteristics and consequences. The objective was to know the prevalence of food cravings and aversions, the characteristics of the pattern of foods that are craved or avoided, and the reasons behind their presence. METHODS: Observational, descriptive and cross-sectional study. A validated questionnaire was applied to 370 pregnant and postpartum women in public hospitals. Maternal and neonatal variables were measured with descriptive statistics and those associated with the phenomena under study were identified using logistic regression models and cluster analysis using the multivariate technique. RESULTS: A presence of cravings from 71 to 80% and aversions from 55 to 65% was detected. The most craved foods were fruits and sweet foods and the most avoided meats and mate. The maternal characteristics predictive of cravings were: being younger (OR 0.94), vomiting (OR 2.23), and having gained more weight than expected were negatively associated with the presence of cravings (OR 0.44). The variables associated with the aversions were the absence of a history of hypertension (OR 0.13), a history of macrosomia (OR 2.70), nausea (OR 1.86) and complications during pregnancy (OR 2.23). DISCUSSION: This work allowed to characterize food cravings and aversions during pregnancy and to know their high frequency.

Introducción: Las gestantes suelen experimentar aversiones y antojos alimentarios, de los cuales se conocen poco sus características y consecuencias. El objetivo fue conocer la prevalencia de los antojos y aversiones alimentarias, las características del patrón de alimentos que son antojados o evitados y los motivos que subyacen ante su presencia. Métodos: Estudio observacional, descriptivo y transversal. Un cuestionario validado se aplicó a 370 embarazadas y puérperas en hospitales públicos. Las variables maternas y neonatales se midieron con estadísticas descriptivas y se identificaron aquellas asociadas a los fenómenos en estudio empleando modelos de regresión logística y un análisis por clusters utilizando la técnica multivariante. Resultados: Se detectó una presencia de antojos del 71 al 80% y de aversiones del 55 al 65%. Los alimentos más antojados fueron las frutas y los alimentos dulces y los mayormente rechazados las carnes y el mate. Las características maternas predictoras de antojos fueron: tener menor edad (OR 0.94), vómitos (OR 2.23), y el haber ganado más peso de lo esperado se asoció negativamente con la presencia de antojos (OR 0.44). Las variables asociadas a las aversiones fueron la ausencia de antecedentes de hipertensión (OR 0.13), antecedentes de macrosomía (OR 2.70), náuseas (OR 1.86) y complicaciones durante el embarazo (OR 2.23). Discusión: Este trabajó permitió caracterizar los antojos y aversiones alimentarias durante el embarazo y conocer su elevada frecuencia.

Diagnóstico prenatal de peritonitis meconial fetal: Reporte de caso y revisión de la literatura Prenatal

Se comunica el diagnóstico ultrasonográfico prenatal de un caso de peritonitis meconial en un feto de 33 semanas, quien nació de parto pretérmino y se confirmó el diagnóstico con ultrasonografía, radiografía y cirugía. El neonato fue sometido a laparotomía exploratoria, en la cual se desbridó un pseudoquiste meconial, resecándose el área intestinal perforada, y se realizó anastomosis términoterminal. La evolución inicial fue tórpida, pero finalmente fue dado de alta con buen funcionamiento intestinal.

We report the prenatal ultrasonographic diagnosis of a case of meconium peritonitis in a 33-week fetus, who was born preterm and the diagnosis was confirmed with ultrasound, radiography and postnatal surgery. The neonate underwent exploratory laparotomy, in which a meconium pseudocyst was debrided, the perforated intestinal area was resected and end-to-end anastomosis was performed. The initial evolution was torpid, but he was finally discharged with good intestinal function.