Utilização de luz ultravioleta contínua (UV-C) e luz pulsada para conservação de mangas CV. Tommy Atkins minimamente processadas

Pós-graduação em Agronomia (Produção Vegetal) - FCAV

Effects of UV-B radiation on Lecanicillium spp., biological control agents of the coffee leaf rust pathogen

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

Filtros UV na água de abastecimento público na região da bacia hidrográfica tietê-jacaré: desenvolvimento de método, estudo de ocorrência e concentrações ambientais

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Validação de metodologias de extração e quantificação de pesticidas, diuron, clorpirifós e metil paration em águas subterrâneas em região de cultura de soja, utilizando QuEChERS/HPLC-UV

Pós-graduação em Química - IQ

Toxicity on aquatic organisms exposed to secondary effluent disinfected with chlorine, peracetic acid, ozone and UV radiation

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Method validation using weighted linear regression models for quantification of UV filters in water samples

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Investigations on PVP/Y3BO6:Eu3+, a red Luminescent composite for lighting devices based on near UV-LEDs

This work deals with a red phosphor. Y3BO6:Eu3+, and its corresponding poly(N-vinylpyrrolidone) (PVP)/Y3BO6:Eu3+ luminescent composite film suitable for applications in the next generation of Hg-free lamps based on near ultraviolet (UV) light emitting diodes (LEDs). Well crystallized samples of Y3BO6 powders with the Eu3+ content up to 20 mol% were prepared by the Pechini method. After structural, morphological and optical characterization, the best doping rate of Eu3+ in the matrix was determined to be 15 mol%. This optimal powder, which is highly friable, was easily ground into fine particles and homogeneously dispersed into a PVP polymer solution to give rise to a polymer phosphor composite. Structural and optical features of the composite film have been studied and compared to those of a pristine PVP film and Y3BO6:Eu3+ powder. All the characterization (XRD, SAXS, luminescence...) proved that the red phosphor particles are well incorporated into the polymer composite film which exhibited the characteristic red emission of Eu3+ under UV light excitation. Furthermore, photostability of the polymer/phosphor composite film under UV-LED irradiation was evaluated from exposure to accelerated artificial photoageing at wavelengths above 300 nm.

Stability of a product prepared with Fuerte avocados exposed to gamma and UV-C radiation

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Biodegradação de filmes de polipropileno (PP), poli (hidroxibutirato-co-valerato) (PHBV) e blenda pré-irradiados com luz UV

This work intends to investigate the biodegradation of the polymers and blend films of polypropylene (PP) and poly(hidroxybutirate-valerate) (PHBV), after UV radiation to facilitate the PP degradation, which is a polymer with long chains difficult to degrade by biological agents present in the environment. This polymer is outstanding by its mechanical properties and versatility of industrial and commercial use and the PHBV by its quick biodegradability in the environment. Blends of these materials could to present a commitment between mechanical properties and biodegradability to execute its function and after the discard to have lesser lifetime in the garbage landfills. Another aspect of this work is the controlling effect of PP on PHBV, influencing its degradation time

Estudo do potencial de associações de ZnO com os produtos naturais ácido cafeico e ferúlico como filtros solares híbridos: [recurso eletrônico]

In this work were studied associations of ZnO with the natural products caffeic and feluric acids. Two preparation methods were used, that is, the sol-gel and a reflux procedure. In the sol-gel method, ZnO is produced by the basics hydrolysis of precursors in the presence of the organic filters (caffeic and feluric acids), which results in 30 nm (or less) ZnO particles with the organic filters (in dissociated form) bonded to the surface of ZnO. In the reflux method, a dispersion of ZnO in a water/ethanol mixture was kept under reflux (50oC/4h) in the presence of the organic acids. The ZnO particles used in the reflux method have a higher diameter than sol-gel ZnO particles, but the prepared associated product ZnO/Organic acids were similar. Despite of the difference in relation to crystallinity between the products, the preparation methods resulted in analogous associations with respect to the interaction of the organic filters with the ZnO surface. The caffeic/ZnO associations presented low photostability, which lead to the degradation of the organic filter. The other associations (feluric acid/ZnO) presented satisfactory results. The FT-IR spectroscopy confirmed the formation of the association, and the nature of the bond formed compared with the Zn-O bond in Zn2+/Felutic acid complexes. The isolated organic and inorganic filters, along with the associations were analyzed by diffuse reflectance spectroscopy and Uv-vis spectroscopy. The absorption edges and the critical wavelengths were analyzed and the effects of Zn-O bonds in feluric acid/ZnO associations described as a function of the relative position of the π/π* system of the organic filter. Finally the performance of the hybrid filters were investigated in terms of the absorption of UVA and UVB radiations, with the UVA/UVB ratio, an efficiency parameter largely used in the description of solar filters, sunscreen and suncare products

Desenvolvimento de estrutura para purificação de água potável, através da irradiação de UV com lâmpadas fluorescentes especiais

Pós-graduação em Engenharia Elétrica - FEIS

Validação e aplicação de método para análise de pesticidas em água para consumo humano de dourados (ms) por CLAE/UV e CG/DTE

Indiscriminate and inappropriate use of pesticides in agriculture has been pointed out for increasing health problems and environmental damage. Considering that water resources are the principal destiny of those compounds after application, the present study presents optimization and validation of two simple and effi cient analytical methods for pesticides quantifi cation in both surface and groundwater. Were selected the pesticides more commonly used at Dourados (MS - Brazil), region with intense agricultural activity. Pesticides were preconcentrated by solid-phase extraction using C18 (500 mg) cartridges and then divided in two groups for elution and quantifi cation: 2.4-D and 2.4-DCP were eluted with methanol and quantifi ed by high performance liquid chromatography with ultra-violet detector (HPLC-UV) while atrazine, DIA, DEA, trifl uralin and methyl parathion were eluted with ethylacetate (1:1, v/v) and quantifi ed by gas chromatography with thermionic specifi c detector (GC-TSD). The methods showed satisfactory accuracy (76-107%) and precision (<12%) for the substances analyzed at the fortifi ed levels selected for the study, except for DIA (<51%). Study of pesticide stability also presented good results: C18 cartridges could be stored for at least for 21 days at -20ºC with no signs of the compounds degradability. Both methods limits of quantifi cation of the pesticides (0.22 - 0.48 μg L-1) are in accordance to the levels currently established by the Brazilian national legislation for pesticides in water. Although only the pesticide 2.4-D has been detected in two distinct collection points in the study period of time, this work warns for the requirement of systematical analysis of pesticides presence in water destined to human consume, principally in areas of intense agriculture activity. Such monitoring can provide subsidies for public environmental policies.

Analysis of fluoxetine and norfluoxetine in human plasma by HPLC-UV using a high purity C18 silica-based SPE sorbent

This paper reports on the development and validation of a simple and sensitive method that uses solid phase extraction (SPE) and liquid chromatography with ultraviolet detection to analyze fluoxetine (FLX) and norfluoxetine (NFLX) in human plasma samples. A lab-made C18 SPE phase was synthesized by using a sol–gel process employing a low-cost silica precursor. This sorbent was fully characterized by nuclear magnetic resonance (NMR), Fourier-transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM) to check the particles' shape, size and C18 functionalization. The lab-made C18 silica was used in the sample preparation step of human plasma by the SPE-HPLC-UV method. The method was validated in the 15 to 500 ng mL 1 range for both FLX and NFLX using a matrix matched curve. Detection limits of 4.3 and 4.2 ng mL 1 were obtained for FLX and NFLX, respectively. The repeatability and intermediary precision achieved varied from 7.6 to 15.0% and the accuracy ranged from 14.9 to 9.1%. The synthesized C18 sorbent was compared to commercial C18 sorbents. The average recoveries were similar (85–105%), however the lab-made C18 silica showed fewer interfering peaks in the chromatogram. After development and validation, the method using the lab-made C18 SPE was applied to plasma samples of patients under FLX treatment (n ¼ 6). The concentrations of FLX and NFLX found in the samples varied from 46.8–215.5 and 48.0–189.9 ng mL 1 , respectively.

UV laser photofabrication of waveguide couplers using self-patterning organic-inorganic hybrids

Planar waveguides with controlled refractive index were produced using thin films of sol-gel derived organic-inorganic hybrids, so called di-ureasils. Spectroscopic ellipsometry was used to characterize the films thickness and refractive index. UV-laser direct-writing method was used to produce Y-splitter structures with coupling ratio of 50% without the need of photoinitiators.

Fotocatálise heterogênea de enterococcus faecalis e pseudomonas aeruginosa desencadeada pela ação da luz UV e branca em espátulas com revestimento de nanopartículas TiO2 e Ag

Nanotechnology, the science of minuscule, has developed products which are able t o manipulate atoms and molecules that could be applied in the sterilization process of dental instruments. Objetives: The objective of the present study was to evaluate the self-cleaning action of TiO2 and Ag nanoparticles coating on dental instruments by the photocataliys process under UV and visible light irradiation. Material and method: Microbiologic tests were done using dental cement spatulas coated with TiO2 and Ag nanoparticles (one or three layers), and contaminated with 10 mcrl of Pseudomonas aeruginosa and Enterococcus faecalis, respectively. After contamination, they were exposed to ultraviolet light and visible light for 120 minutes. Next, they were transferred to and stored in test tubes with BHI (Brain Heart Infusion) and incubated in 35 to 37 °C. Checking times for bacterial growth and for control and retrieval tests were done at: 24, 48, 72 and 96 hours. Result: The Pseudomonas aeruginosa was inactive after 120 minutes of ultraviolet light irradiation, thus confirming the heterogeneous photocatalytic activity of TiO2 and Ag. The Pseudomonas aeruginosa was not inactivated under visible light irradiation and the Enterococcus faecalis was not inactivated under UV and visible light irradiation of the dental cement spatulas coated with TiO2 and Ag nanoparticles in the readings to 96 hours, showing bacterial growth. Conclusion: There were no influence of one or three layers of TiO2 and Ag nanoparticles coating of the spatulas in the results. The heterogeneous photocatalysis activity of TiO2 and Ag under UV light irradiation was confirmed for Pseudomonas aeruginosa but not under visible light. Enterococcus faecalis did not confirmed the photocatalytics activity of TiO2 and Ag under UV light irradiation and visible lights irradiation.