Palabras clave: fotocatálisis heterogénea, método sol-gel, dinámica del reactor RESUMEN La degradación de compuestos orgánicos no biodegradables presentes en aguas residuales es un punto central de la fotocatálisis solar debido a su alta eficiencia y aceptables costos de operación. Se estudió la degradación de 2,5-diclorofenol (2,5-DCF) en solución acuosa con concentración inicial variable (C0 ≤ 98 mg/L), por fotólisis y fotocatálisis solar con un reactor de placa plana (1 m 2 ) y vidrio impregnado con TiO2 sintetizado por el método sol-gel. Se establecieron dos variables de respuesta, la demanda química de oxígeno y la concentración de 2,5-DCF determinada a 280 nm, por tres factores: ángulo de inclinación (20º y 26º), flujo (355 L/h y 407 L/h) y dos procesos (fotólisis y fotocatálisis). Lo anterior en condiciones de alta (ħʋprom = 847.4 W/m 2 ) y baja intensidad (ħʋprom = 453.6 W/m 2 ) de radiación solar, para lo cual se recirculó la solución acuosa sobre la placa de vidrio durante 60 min, bajo régimen laminar y con muestras cada 5 min. Se determinaron las constantes de velocidad K1 (min -1 ) y K2 (mol/L) -1 de orden primero y cero de reacción, respectivamente. Se consideraron elementos de la dinámica del reactor en la evaluación de la cinética química de reacciones fotocatalíticas. Se alcanzaron porcentajes de degradación de 2,5-DCF superiores al 98 % por fotocatálisis solar.Key words: heterogeneous photocatalysis, sol-gel method, reactor dynamics ABSTRACTThe interest in solar photocatalysis degradation of non-biodegradable organic compounds in wastewater has raised due to its high efficiency and acceptable operation costs. The degradation of an aqueous 2,5-Dichlorophenol (2,5-DCP) solution with variable initial concentration (C0 ≤ 98 mg/L) was performed by photolysis and solar photocatalysis, using a flat glass plate (1 m 2 ) impregnated with TiO2 synthetized by
The MTHFR A1298C CC genotype was associated with an increased risk of developing childhood ALL. However, a decreased risk to ALL with the combination of MTHFR 677CC+1298AC genotypes was found.
Las hormigas son insectos eusociales de amplia diversidad funcional y taxonómica, con distribución mundial en diversos ecosistemas terrestres (algunas introducidas por el hombre), a excepción de los polos y en los picos de las altas montañas. Se han descrito cerca de 15.947 especies. En México, se conocen 927 dentro de 93 géneros, y para el estado de Durango se registran 60 especies dentro de 25 géneros. Sin embargo, el conocimiento de Formicidae en Durango es escaso porque es uno de los estados que menos atención ha recibido; esto, debido a la carencia de especialistas, así como, la extensión territorial del mismo. Con el objetivo de conocer la mirmecofauna del estado de Durango, se realizaron recolectas cada 15 días entre el 1 agosto 2016 y el 1 agosto 2017, en 56 sitios de 19 municipios ubicados en diferentes ecoregiones del Estado. Se recolectaron 40 especies pertenecientes a 24 géneros; la subfamilia Myrmicinae fue la más diversa con 21 especies, seguida por Formicinae (12 spp.), Dolichoderinae (5 spp.) y Dorylinae y Ponerinae con una especie cada una. Se registran 10 especies de hormigas más para el estado de Durango, aumentando la riqueza de 60 a 70 especies y de 25 a 32 géneros. Este estudio representa el primer esfuerzo para conocer la mirmecofauna del estado de Durango, México.
Background: The identification of genetic risk factors for Acute Lymphoblastic Leukemia (ALL), are increasingly urgent and necessary.Objective: The purpose of this study is to determine the association of the genetic polymorphisms ABCC1 rs3743527, NCF4 rs1883112 and CBR3 rs1056892 with ALL.Methods: DNA samples were obtained in 71 children with ALL (from 2 to 18 years) and in 71 controls without ALL, to determine the polymorphisms by real-time polymerase chain reaction (qPCR), using specific TaqMan probes in a StepOne® thermal cycler (Applied Biosystems, United States).Results: The results of the Odds Ratio analysis show that in the rs1883112 polymorphism of the NCF4 gene, the heterozygous allele has a risk effect for ALL (OR = 3.1870, CI = 1.8880–7.9383 and p = 0.0002), in turn the mutated genotype (AA) is associated with a protective effect (OR = 0.26, 0.1248 to 0.5434 and p = 0.0003). On the other hand, the CBR3 rs1056892 polymorphism shows a significant association of risk to ALL, in the presence of the HT genotype (OR = 2.77, IC = 1.3837 to 5.5651 and p = 0.004) and the mutated genotype of this polymorphism has a significant association with protection to ALL in the HM genotype (OR = 0.52, IC = 0.2639 to 1.0304 and p = 0.05). While the inheritance models of the polymorphisms let us see that of the rs1883112 polymorphism of the NCF4 polymorphism; the HT genotype of the codominant model shows a protective effect against ALL (OR = 0.4117, IC = 0.1718 to 0.9866 and p = 0.04), the recessive model shows us and confirms what we already saw in table number 3, being that there is an association with protective effect in the HM genotype (OR = 0.2604, IC = 0.1248 to 0.5434 and p = 0.0003). In the polymorphism rs1056892 of the CBR3 gene, a protection association was found in the heterozygous allele of the codominant model (OR = 0.3448, IC = 0.1375 to 0.8896 and p = 0.0274). In addition, the recessive inheritance model for the HM genotype shows a protective effect to ALL, (OR = 0.52, CI = 0.9919 to 3.8638 and p = 0.05).Conclusion: There is an evident impact of the NCF4 rs1883112 and CBR3 rs1056892 polymorphisms with an increased risk of susceptibility to ALL; Likewise, through the codominant inheritance model, the effect of the variation of the CBR3 rs1056892 gene as a protective factor against ALL was evaluated.
Satellite images of the grassland area in Durango M´exico were obtained of altitude, slope, average annual temperature, annual precipitation, type of vegetation, type of soil, normal vegetation index, percentage of herbaceous and percentage of bares soil, in order to relate them with grasshopper density population (GDP) surveyed in 35 sampling sites from June to November in 2003 in the study area. A stepwise regression analysis was performed with the most abundant grasshopper species Phoetaliotes nebrascensis (Thomas), Melanoplus lakinus (Scudder) and Boopedon nubilum (Say) with data extracted from the satellite images. Results showed R > 0.798, F(4, 27) > 9.86 and P > 0.000016. The significant variables were normal vegetation index, type of vegetation, altitude and precipitation. GDP raster maps were interpolated using the stepwise regression equations. Then, classification neural networks models were used in order to classify GDP maps. Analysis of percentage of classification error showed that the adequate number of hidden neurons was between six and twelve. Results of error classification were 21% for P. nebrascensis, 5% for M. lakinus and 20% for B. nubilum. Neural networks are practical tools to classify grasshopper population and it will help to take control measurements in overpopulated areas.
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