Gas sensor properties of zno nanorods grown by chemical bath deposition

The present work shows a study about the growing of ZnO nanorods by chemical bath deposition (CBD) and its application as gas sensor. It was prepared ZnO nanorods and Au decorated ZnO nanorods and the samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and gas sensing response measurements. The results obtained by XRD show the growth of ZnO phase. It was possible to observe the formation of uniform dense well-aligned ZnO nanorods. The results obtained also revealed that Ag nanoparticles have decorated the surface of ZnO nanorods successfully. Au nanoparticles with diameter of a few nanometers were distributed over the ZnO surface nanorods. The gas sensing response measurements showed a behavior of n type semiconductor. Furthermore, the Au-functionalized ZnO nanorods gas sensors showed a considerably enhanced response at 250 and 300 °C.

Nitric oxide reduces oxidative damage induced by water stress in sunflower plants

Drought is one of the main environmental constraints that can reduce plant yield. Nitric oxide (NO) is a signal molecule involved in plant responses to several environmental stresses. The objective of this study was to investigate the cytoprotective effect of a single foliar application of 0, 1, 10 or 100 µM of the NO donor sodium nitroprusside (SNP) in sunflower plants under water stress. Water stressed plants treated with 1μM SNP showed an increase in the relative water content compared with 0 μM SNP. Drought reduced the shoot dry weight but SNP applications did not result in alleviation of drought effects. Neither drought nor water stress plus SNP applications altered the content of photosynthetic pigments. Stomatal conductance was reduced by drought and this reduction was accompanied by a significant reduction in intercellular CO2 concentration and photosynthesis. Treatment with SNP did not reverse the effect of drought on the gas exchange characteristics. Drought increased the level of malondialdehyde (MDA) and proline and reduced pirogalol peroxidase (PG-POD) activity, but did not affect the activity of superoxide dismutase (SOD). When the water stressed plants were treated with 10 μM SNP, the activity of PG-POD and the content of proline were increased and the level of MDA was decreased. The results show that the adverse effects of water stress on sunflower plants are dependent on the external NO concentration. The action of NO may be explained by its ability to increase the levels of antioxidant compounds and the activity of ROS-scavenging enzymes.

Síntese, Caracterização Estrutural e Análise do Potencial Catalítico, para a Preparação de Biodiesel, de Niobatos Não Estequiométricos com Estrutura Tungstênio Bronze

Pós-graduação em Química - IBILCE

Biomarker evaluation in fish after prolonged exposure to nano-TiO2: influence of illumination conditions and crystal phase

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Changes in chemical profile of cephalic salivary glands of Scaptotrigona postica (Hymenoptera, Meliponini) workers are phase-related

Most advanced eusocial bees recruit their nestmates to food resources. Recently, studies in Meliponini species showed that the cephalic salivary (labial) glands (CSGs) are responsible for the production of scent-trail pheromones. Studies on CSGs have shown changes in glandular cell morphology since the worker emerges from brood combs (newly emerged) till forager phase, which may be correlated to changes in the composition of secretion produced. However, no study has been made till now regarding to the composition of CSGs secretion of Scaptotrigona postica and the chemical changes that occur in this secretion according to the worker's life phase or tasks performed. In this study, the chemical profile of CSG secretion in S. postica workers was studied. Glands were taken from specimens newly emerged (NE), working in the brood combs area (CA) and forager (FO) and were analyzed by gas chromatography-mass spectrometry. The results showed that glandular secretion consists of oxygenated compounds of middle volatility (acids, alcohols, aldehydes, ketones, esters and ether), and their quantity varies among the different phases of life, increasing as the individual undergoes from intra- to extra-colonial activities. The NE phase contained the smallest variety and quantity of compounds. Due to the variability of compounds, the CA workers were separated into 3 groups according to the chemical constitution of their secretion. Forager workers showed the largest quantity and variety of chemical compounds. The major compounds in forager gland secretion are 7-hexadecen-1-yl acetate and 5-tetradecen-1-yl acetate. Statistical analysis indicates that the chemical composition of glandular secretion is task-related.

Avaliação do processo de contaminação e remediação de água subterrânea por hidrocarbonetos

Pós-graduação em Engenharia Civil e Ambiental - FEB

Greenhouse gas balance associated with sugarcane production in South-Central Brazil, considering the management and expansion

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Duração da eclosão e temperatura de incubação sobre a qualidade dos pintos, seu desempenho e qualidade de carne

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)