Desiccation tolerance of Tapirira obtusa seeds collected from different environments

O objetivo deste trabalho foi avaliar a sensibilidade à dessecação de sementes de Tapirira obtusa (Benth.) J. D. Mitchell provenientes de três ambientes e submetidas a duas velocidades de secagem. As sementes foram coletadas em área de campo rupestre, Cerrado e em mata ciliar, da região de Lavras, MG. As sementes foram submetidas à secagem com cloreto de magnésio (secagem lenta) ou sílica gel (secagem rápida), em ambiente fechado, até os graus de umidade de 40%, 30%, 20% e 10%, considerando como controle o percentual de germinação na umidade inicial em cada ambiente, a qual variou de 47% a 50%. Foram avaliados os percentuais de germinação e de plântulas normais e também o índice de velocidade de germinação. Nos três ambientes analisados, não houve efeito da secagem lenta sobre a germinação das sementes. Sementes oriundas do Cerrado apresentaram pequena redução da germinação, quando submetidas à secagem rápida. Sementes oriundas de áreas rupestres apresentaram aumento na germinação quando submetidas à secagem rápida. Sementes oriundas de mata ciliar não apresentaram redução na germinação, independente da velocidade de secagem. Os resultados sugerem que sementes de T. obtusa não apresentam sensibilidade à dessecação.

Refluxo gastroesofágico: estudo comparativo da receptividade e sensibilidade entre seriografia e ultrassonografia

OBJETIVO: Estudo comparativo da receptividade (colaboração) e sensibilidade da seriografia do esôfago, estômago e duodeno em relação à ultrassonografia do esôfago intra-abdominal em pacientes com suspeita de refluxo gastroesofágico. MATERIAIS E MÉTODOS: Foram incluídos no estudo 42 pacientes pediátricos (26 masculinos, com idade média de 33,64 ± 34,33 meses, e 16 femininos, com idade média de 31,02 ± 35,56 meses) com suspeita de refluxo gastroesofágico, os quais foram submetidos, inicialmente, a seriografia do esôfago, estômago e duodeno, e posteriormente, a ultrassonografia do esôfago intra-abdominal. RESUL-TADOS: A análise estatística comparativa entre os sexos e as idades sugere não haver evidência de associação com a colaboração, tanto para a seriografia do esôfago, estômago e duodeno como para a ultrassonografia do esôfago intra-abdominal. Entretanto, na classificação quanto ao tipo de colaboração, a técnica de seriografia do esôfago, estômago e duodeno apresentou menos de 50% de colaboração, enquanto 80,49% dos pacientes colaboraram com a ultrassonografia do esôfago intra-abdominal. Quanto à sensibilidade do diagnóstico de refluxo gastroesofágico, a técnica de ultrassonografia do esôfago intra-abdominal (85,7%) foi significativamente superior à de seriografia do esôfago, estômago e duodeno (47,6%). CONCLUSÃO: O presente estudo sugere que se proceda a ultrassonografia do esôfago intra-abdominal, mesmo na ausência de refluxo gastroesofágico na seriografia do esôfago, estômago e duodeno.

Rhodophyta de ambientes lóticos de unidades de conservação da região sul do Brasil

Species of Rhodophyta from 10 Conservation Units from the south region of Brazil were surveyed. The samplings were carried out in 105 stream reaches, consisting of 10 m length transects. The floristic survey involved 80 populations, representing three genera, Batrachospermum, Kumanoa and Hildenbrandia plus the 'Chantransia' stages. Batrachospermum was represented by five species (B. arcuatum Kylin, B. atrum (Hudson) Harvey, B. helminthosum Bory, B. keratophytum Bory and B. puiggarianum Grunow in Wittrock & Nordstedt). The genus Kumanoa was represented by K. abilii (Reis) Necchi Junior & Vis and K. ambigua (Montagne) Entwisle et al., while Hildenbrandia only by H. angolensis W.West & G.S.West. Our results confirm Batachospermum as the best represented genus, in terms of species number, among freshwater Rhdophyta. B. arcuatum was a new record for the south region of Brazil, thus extending its austral distribution range.

Nb-containing hematites Fe2-xNbxO3: The role of Nb5+ on the reactivity in presence of the H2O2 or ultraviolet light

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

The interaction between atoms of Au and Cu with clean Si(111) surface: A study combining synchrotron radiation grazing incidence X-ray fluorescence analysis and theoretical calculations

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Removal of metal ions from aqueous solution by chelating polymeric hydrogel

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

New materials based on modified synthetic Nb2O5 as photocatalyst for oxidation of organic contaminants

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Photocatalyst TiO2-Co: the effect of doping depth profile on methylene blue degradation

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

Photocatalytic degradation of methylene blue by TiO2-Cu thin films: Theoretical and experimental study

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

The activity of amino acids produced by Paenibacillus macerans and from commercial sources against the root-knot nematode Meloidogyne exigua

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Purification of an antibacterial compound from Lantana lilacina

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Preparation of CuO/SiO2 and photocatalytic activity by degradation of methylene blue

A photocatalyst based on CuO/SiO2 was prepared, and evaluated for the degradation of methylene blue in aqueous medium. The photocatalyst was obtained by calcination method of copper salt, in the presence of silica. The characterization by XRD, FTIR, and TPR techniques confirmed the formation of CuO as active phase. SEM studies showed CuO deposited on the surface of SiO2. By ESI-MS, it was demonstrated that the degradation of methylene blue occurs through successive hydroxylations. Photodegradation assays showed that CuO/SiO2 was efficient for degradation, and that the material worked better in the presence of UV light.

Photocatalytic decomposition of methylene blue via Fenton mechanisms by silicon wafer doped with Au and Cu: a theoretical and experimental study

In this work, we studied the photocatalytic and the structural aspects of silicon wafers doped with Au and Cu submitted to thermal treatment. The materials were obtained by deposition of metals on Si using the sputtering method followed by fast heating method. The photocatalyst materials were characterized by synchrotron-grazing incidence X-ray fluorescence, ultraviolet-visible spectroscopy, X-ray diffraction, and assays of H(2)O(2) degradation. The doping process decreases the optical band gap of materials and the doping with Au causes structural changes. The best photocatalytic activity was found for thermally treated material doped with Au. Theoretical calculations at density functional theory level are in agreement with the experimental data.

Synthesis, structure, and thermal stability of poly(methyl methacrylate)-co- poly(3-tri(methoxysilyil)propyl methacrylate)/ montmorillonite nanocomposites

The structure and the thermodegradation behavior of both poly(methyl methacrylate)-co-poly(3-tri(methoxysilyil)propyl methacrylate) polymer modified with silyl groups and of intercalated poly(methyl methacrylate)-co-poly(3- tri(methoxysilyil)propyl methacrylate)/Cloisite 15A™ nanocomposite have been in situ probed. The structural feature were comparatively studied by Fourier transform infrared spectroscopy (FTIR), 13C and 29Si nuclear magnetic resonance (NMR), and small angle X-ray scattering (SAXS) measurements. The intercalation of polymer in the interlayer galleries was evidenced by the increment of the basal distance from 31 to 45 Å. The variation of this interlayer distance as function of temperature was followed by in situ SAXS. Pristine polymer decomposition pathway depends on the atmosphere, presenting two steps under air and three under N2. The nanocomposites are more stable than polymer, and this thermal improvement is proportional to the clay loading. The experimental results indicate that clay nanoparticles play several different roles in polymer stabilization, among them, diffusion barrier, charring, and suppression of degradation steps by chemical reactions between polymer and clay. Charring is atmosphere dependent, occurring more pronounced under air. © 2012 Society of Plastics Engineers.

TiO2-Cu photocatalysts: A study on the long- and short-range chemical environment of the dopant

In this study, the short- and long-range chemical environments of Cu dopant in TiO2 photocatalyst have been investigated. The Cu-doped and undoped TiO2 specimens were prepared by the sol-gel approach employing CuSO4·5H2O and Ti(O-iPr)4 precursors and subjecting the dried gels to thermal treatment at 400 and 500 C. The photocatalytic activity, investigated by methylene blue degradation under sunlight irradiation, showed a significantly higher efficiency of Cu-doped samples than that of pure TiO2. The X-ray diffraction results showed the presence of anatase phase for samples prepared at 400 and 500 C. No crystalline CuSO4 phase was detected below 500 C. It was also found that doping decreases the crystallite size in the (004) and (101) directions. Infrared spectroscopy results indicated that the chemical environment of sulfate changes as a function of thermal treatment, and UV-vis spectra showed that the band gap decreases with thermal treatment and Cu doping, showing the lowest value for the 400 C sample. X-ray absorption fine structure measurements and analysis refinements revealed that even after thermal treatment and photocatalytic assays, the Cu2+ local order is similar to that of CuSO4, containing, however, oxygen vacancies. X-ray photoelectron spectroscopy data, limited to the near surface region of the catalyst, evidenced, besides CuSO4, the presence of Cu1+ and CuO phases, indicating the active role of Cu in the TiO2 lattice. © 2013 Springer Science+Business Media New York.