Optical and morpho-structural properties of ZnO nanostructured particles synthesized at low temperature via air-assisted USP method

Here, we report on the ZnO nanoparticles processing employing low-temperature (500 °C) ultrasonic spray pyrolysis (USP) method, using different Zn nitrate precursor solution concentrations (0.01, 0.1 and 1.0 M). Particle structural, morphological and luminescence characteristics were studied based on X-ray powder diffractometry, Fourier transform infrared spectroscopy, transmission electron microscopy (TEM/HRTEM), thermal analysis, UV–Vis diffuse reflectance spectra and photoluminescence measurements (PL). The generated so-called secondary particles have a hexagonal ZnO wurtzite-type crystalline structure with preferred orientation of (101) plane and quasi-spherical in shape. It was shown that such particle structural and morphological features are independent on the precursor solution concentrations used. All the PL spectra illustrate a strong green-yellow typical emission band exhibiting the corresponding redshift and variation of direct band gap from 3.22 to 3.12 eV with the increase in precursor concentration. The thermal analysis confirmed high thermal nanoparticles stability. The results proved that USP method successfully produces ZnO nanoparticles using neither dispersing agents nor post-heating treatments at high temperature, which allows rapid, continuous, single-step preparation, demonstrating a high potential for industrial applications

Hacia el uso sostenible del agua en la producción. Proyecto Custodia del Agua en la Cuenca del Santa Lucía.

El concepto de custodia del agua surge como una respuesta a problemas comunes en el uso responsable y sostenible del agua dulce y propone esfuerzos colectivos con origen en iniciativas individuales, voluntarias y colaborativas para gestionarla de manera sostenible

Oxidative Stress, Gene Expression, and Protein Changes Induced in the Human Placenta during Labor

Malperfusion of the placenta has been implicated as a cause of oxidative stress in complications of human pregnancy, leading to release of proinflammatory cytokines and anti-angiogenic factors into the maternal circulation. Uterine contractions during labor are known to be associated with intermittent utero-placental perfusion. We therefore tested whether oxidative stress, proinflammatory cytokines, and angiogenic regulators were increased in placentas subjected to short (<5 hours) and long (>15 hours) labor compared with nonlabored controls delivered by cesarean section. In addition, broader changes in gene transcripts were assessed by microarray analysis. Oxidative stress, activation of the nuclear factor-κB pathway, tumor necrosis factor-α and interleukin 1β all increased in placental tissues after labor. Stabilization of hypoxia-inducible factor-1α and increased vascular endothelial growth factor soluble receptor-1 were also observed. By contrast, tissue levels of placenta growth factor decreased. Apoptosis was also activated in labored placentas. The magnitude of these changes related to the duration of labor. After labor, 55 gene transcripts were up-regulated and 35 down-regulated, and many of these changes were reflected at the protein level. In conclusion, labor is a powerful inducer of placental oxidative stress, inflammatory cytokines, and angiogenic regulators. Our findings are consistent with intermittent perfusion being the initiating cause. Placentas subjected to labor do not reflect the normal in vivo state at the molecular level