We developed a colorimetric and fluorescence dual-signal sensor for detecting lipase activity based on methyl thioglycolate (MT) functionalized gold nanoparticles (MT-AuNPs) and CdS quantum dots (CdS QDs). It is the first time that was developed a dual-signal sensing strategy for lipase activity based on the inner-filter effect (IFE) between MT-AuNPs and CdS QDs. This probe system (MT AuNPs + CdS QDs) is sensitive and has selective response to the concentration of the lipase, and MT-AuNPs and CdS QDs played as transducer and fluorescer, respectively. The addition of lipase triggered the accumulation and change of color in CdS QDs and MT-AuNPs solution, it also makes the fluorescence intesity of CdS QDs significantly recover. The limit of detection (LOD) was as low as 0.039 μg mL-1 for colorimetric detection as well as 0.012 μg mL-1 for the fluorescence method. This method has been successfully used in the detection of commercial lipases. We believe it would open up a new path for the sensitive and high throughput lipase assay using nanobiosensor.

Nitrogen fertilization has played a significant role in increasing crop yield, and solving problems of hunger and malnutrition worldwide. However, excessive nitrogen inputs do not significantly increase crop yields but may lead to many serious environmental problems. The effects of nitrogen fertilization rate were studied on heavy metal content of corn grains. Our results show that nitrogen fertilization management is beneficial for reducing production costs, protecting the environment, and improving the quality of farm products.

La fertilización nitrogenada ha tenido un rol significativo en incrementar los rendimientos de los cultivos, y resolver problemas de hambre y malnutrición en todo el mundo. Sin embargo, la fertilización nitrogenada excesiva no incrementa los rendimientos de los cultivos significativamente sino que puede conducir a severos problemas ambientales. Los efectos de la tasa de fertilización nitrogenada se estudiaron en el contenido de metales pesados en granos de maíz. Nuestros resultados muestran que el manejo de la fertilización nitrogenada es benéfico para reducir los costos de producción, proteger el ambiente, y mejorar la calidad de productos agrícolas.