Base-assisted synthesis of 4-pyridinate gold(I) metallaligands: a study of their use in self-assembly reactions

The synthesis of di- and tritopic gold(I) metallaligands of the type [(Au4-py)2(μ2-diphosphane)] (diphosphane = bis(diphenylphosphanyl)isopropane or dppip (1), 1,2-bis(diphenylphosphanyl)ethane or dppe (2), 1,3-bis(diphenylphosphanyl)propane or dppp (3) and 1,4-bis(diphenylphosphanyl)butane or dppb (4)) and [(Au4-py)3(μ3-triphosphane)] (triphosphane = 1,1,1-tris(diphenylphosphanylmethyl)ethane or triphos (5) and 1,3,5-tris(diphenylphosphanyl)benzene or triphosph (6)) from [(AuCl)2(μ2-diphosphane)] or [(AuCl)3(μ3-triphosphane)] and 4-pyridylboronic acid in the presence of Cs2CO3 has been conducted. Interestingly, when [(AuCl)2(μ2-dppm)] (dppm = bis(diphenylphosphanyl)methane) was used as a starting material, the cyclic tetranuclear gold(I) compound [(Au4-py)2(CH)2{μ2-Au(PPh2)2}2] (I) was obtained instead. All the products have been characterized by IR and multinuclear NMR spectroscopy, mass spectrometry and elemental analysis and in the case of 1, 3, 5 and I by X-ray crystallography, which showed the presence of aurophilic interactions in all of them. The obtained metallaligands have been used as building blocks in self-assembly reactions with cis-blocked palladium or platinum acceptor moieties producing [2 + 2] metallamacrocycles or trigonal bipyramidal (TBP) [2 + 3] metallacages in good yields. The photophysical properties of both the metallaligands and the corresponding assemblies have been investigated

Modelación hidrológica con el modelo SWAT empleando diferentes distribuciones espaciales del tipo suelo en la cuenca del Río Mixteco

La cuenca del río Mixteco se ubica en el estado de Oaxaca, México y comprende una superficie total de 6 559.20 km2; esta presenta fuerte degradación de sus recursos naturales, derivado principalmente de las acciones antrópicas asociadas a una mala administración de sus recursos naturales. El objetivo de este trabajo fue evaluar el comportamiento del escurrimiento superficial mediante el modelo SWAT (Soil and Water Assessment Tool) en la cuenca del río Mixteco utilizando tanto la distribución espacial de suelo del INEGI (Instituto Nacional de Estadística y Geografía) como la obtenida a través de la técnica de DSM (Mapeo Digital de Suelos). La modelación con INEGI (ModINEGI) correspondió al mapa edafológico de la Serie II escala 1:250,000 y la modelación con DSM (ModDSM) se obtuvo a partir de covariables ambientales. Los indicadores de evaluación del desempeño del modelo SWAT durante la fase de calibración fueron R2 = 0.88 y NSE = 0.87 para ModDSM y R2 = 0.85 y NSE = 0.85 para ModINEGI; sin embargo, durante el periodo de validación, los resultados de ModDSM (R2 = 0.83 y NSE = 0.81) fueron mejores que los de ModINEGI (R2 = 0.83 y NSE = 0.61). Por lo tanto, los resultados indican que la variación espacial de los tipos de suelo obtenida a través de la técnica de DSM, en combinación con la cobertura vegetal y la distribución de las pendientes a nivel cuenca, permiten al modelo SWAT simular de forma adecuada el comportamiento del escurrimiento superficial

El precio del durazno para la toma de decisiones de los productores mexicanos

Peach producers in Mexico form their production expectations based on the future price; they wait for the price to increase in order to continue with the agricultural activity, reason why they do not make the decision of seeking other uses and markets for the fruit, different from the fresh market. The objective of this study was to analyze the dynamics of the formation of the market price of peach in Mexico, its trend and volatility, in order to predict its trajectory through time. The hypothesis was that peach prices present high volatility and a negative trend that converges in a price with a constant. With the methodology of a dynamic model under a simple market, a differential second degree equation and a Brownian equation, it was found that the real price of peach presented severe fluctuation with negative trend; that the trajectory in time led the price of the fruit towards a constant equilibrium price, although it was low compared to the levels in previous periods. Thus, it was confirmed that the future price will not increase in the next 15 years and, as consequence, facing this scenario of uncertainty, the producers of this fruit could cease to continue investing in the activity.Los productores de durazno en México forman sus expectativas de producción basadas en el precio futuro; estos esperan que el precio aumente para seguir con la actividad agrícola, razón por la cual no toman la decisión de buscar otros usos y mercados para la fruta, diferentes al mercado en fresco. El objetivo fue analizar la dinámica de la formación del precio de mercado del durazno en México, su tendencia y volatilidad a fin de pronosticar la trayectoria de este en el tiempo. La hipótesis fue que los precios del durazno presentan alta volatilidad y tendencia negativa que convergen a un precio con constante. Con la metodología de un modelo dinámico bajo un mercado simple, una ecuación diferencial de segundo grado y una ecuación browniana se obtuvo que el precio real del durazno presentó severas oscilaciones con tendencia negativa; que la trayectoria del tiempo condujo al precio de la fruta hacia un precio constante de equilibrio, pero que este fue bajo con respecto a los niveles de los periodos anteriores, por lo que se comprobó que el precio del fruto no aumentará en los próximos 15 años y en consecuencia, ante este escenario de incertidumbre, los productores de dicho fruto podrían dejar de seguir invirtiendo en la actividad

Mechanisms involved in the vasorelaxant effects produced by the acute application of amfepramone in vitro to rat aortic rings

Amfepramone (diethylpropion) is an appetite-suppressant drug used for the treatment of overweight and obesity. It has been suggested that the systemic and central activity of amfepramone produces cardiovascular effects such as transient ischemic attacks and primary pulmonary hypertension. However, it is not known whether amfepramone produces immediate vascular effects when applied in vitro to rat aortic rings and, if so, what mechanisms may be involved. We analyzed the effect of amfepramone on phenylephrine-precontracted rat aortic rings with or without endothelium and the influence of inhibitors or blockers on this effect. Amfepramone produced a concentration-dependent vasorelaxation in phenylephrine-precontracted rat aortic rings that was not affected by the vehicle, atropine, 4-AP, glibenclamide, indomethacin, clotrimazole, or cycloheximide. The vasorelaxant effect of amfepramone was significantly attenuated by NG-nitro-L-arginine methyl ester (L-NAME) and tetraethylammonium (TEA), and was blocked by removal of the vascular endothelium. These results suggest that amfepramone had a direct vasorelaxant effect on phenylephrine-precontracted rat aortic rings, and that inhibition of endothelial nitric oxide synthase and the opening of Ca2+-activated K+ channels were involved in this effect

Leisure-time physical activity and cardiometabolic risk among children and adolescents

OBJECTIVE: To assess the effect of Leisure-time physical activity (LTPA) on cardiometabolic risk by nutritional status in Mexican children and adolescents. METHODS: This was a cross-sectional study conducted with 1,309 participants aged between 5 and 17 years. Nutritional status was classified according to the BMI Z-score by age and gender. A previously validated questionnaire was used to evaluate LTPA; a cardiometabolic risk score was calculated. Multiple linear regression analysis was performed to assess the effect of LTPA on cardiometabolic risk. RESULTS: After adjusting for risk factors, mild LTPA were positively associated with cardiometabolic risk score (ßMildvsIntenseLTPA: 0.68; 95% CI: 0.18 to 1.18; pfortrend = 0.007). This association became stronger when estimated for overweight (ß MildvsIntenseLTPA: 1.24; 95% CI: 0.24 to 2.24; pfortrend = 0.015) and obese participants (ß MildvsIntenseLTPA: 1.02; 95% CI: 0.07 to 1.97; pfortrend= 0.045) CONCLUSION: Mild LTPA was positively associated with cardiometabolic risk in overweight and obese children and adolescents. Given the emerging childhood obesity epidemic in Mexico, these results may be useful in the design of strategies and programs to increase physical activity levels in order to achieve better health

Leisure-time physical activity and cardiometabolic risk among children and adolescents ଝ Leisure-time activity and cardiometabolic risk PALAVRAS-CHAVE

Abstract Objective: To assess the effect of Leisure-time physical activity (LTPA) on cardiometabolic risk by nutritional status in Mexican children and adolescents. Methods: This was a cross-sectional study conducted with 1,309 participants aged between 5 and 17 years. Nutritional status was classified according to the BMI Z-score by age and gender. A previously validated questionnaire was used to evaluate LTPA; a cardiometabolic risk score was calculated. Multiple linear regression analysis was performed to assess the effect of LTPA on cardiometabolic risk. Results: After adjusting for risk factors, mild LTPA were positively associated with cardiometabolic risk score (␤ Mild vs Intense LTPA : 0.68; 95% CI: 0.18 to 1.18; p for trend = 0.007). This association became stronger when estimated for overweight (␤ Mild vs Intense LTPA : 1.24; 95% CI: 0.24 to 2.24; p for trend = 0.015) and obese participants (␤ Mild vs Intense LTPA : 1.02; 95% CI: 0.07 to 1.97; p for trend = 0.045). Conclusion: Mild LTPA was positively associated with cardiometabolic risk in overweight and obese children and adolescents. Given the emerging childhood obesity epidemic in Mexico, these results may be useful in the design of strategies and programs to increase physical activity levels in order to achieve better health. © 2014 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda. All rights reserved. Intensa : 1,02; IC 95%: 0,07 a 1,97; P para tendência = 0,045). Conclusão: A AFL leve foi positivamente associada ao escore de risco cardiometabólico em crianças e adolescentes acima do peso e obesos. Considerando a epidemia de obesidade infantil emergente no México, esses resultados poderão ser úteis na elaboração de estratégias e programas para aumentar os níveis de atividade física a fim de obter uma saúde melhor

Histopathological alterations in mice under sub-acute treatment with Hintonia latiflora methanolic stem bark extract

The indiscriminate use of herbal products is increasingly growing worldwide; nonetheless consumers are not warned about the potential health risks that these products may cause. Hintonia latiflora (Hl) is a tree native to the American continent belonging to the Rubiaceae family and its stem bark is empirically used mainly to treat diabetes and malaria; supplements containing Hl are sold in America and Europe without medical prescription, thus scientific information regarding its toxicity as a consequence of a regular consumption is needed. In the present study, the histopathological effect of 200 and 1000 mg/kg of Hl methanolic stem bark extract (HlMeOHe) was evaluated in the small bowel, liver, pancreas, kidneys and brain of CD-1 male mice after oral sub-acute treatment for 28 days. No histopathological alterations were observed in the brain of the treated animals; however, mice presented diarrhea from day 2 of treatment with both doses. No histological changes were observed in the tissues collected from the animals treated with 200 mg/kg, except for the liver that depicted periportal hepatitis. Animals treated with the higher dose showed in the liver sections hydropic degeneration, hepatitis and necrosis small bowel sections showed dilated mucosal vessels, kidney sections depicted tubular necrosis and in pancreas sections, hydropic degeneration of the pancreatic islets was observed. In conclusion, HlMeOHe damaged the liver with an oral dose of 200 mg/kg, and at 1000 mg/kg injured the kidneys and pancreas of the CD1 male mice