The effect of flooding on the exchange of the volatile C₂-compounds ethanol, acetaldehyde and acetic acid between leaves of Amazonian floodplain tree species and the atmosphere

The effect of root inundation on the leaf emissions of ethanol, acetaldehyde and acetic acid in relation to assimilation and transpiration was investigated with 2–3 years old tree seedlings of four Amazonian floodplain species by applying dynamic cuvette systems under greenhouse conditions. Emissions were monitored over a period of several days of inundation using a combination of Proton Transfer Reaction Mass Spectrometry (PTR-MS) and conventional techniques (HPLC, ion chromatography). Under non-flooded conditions, none of the species exhibited measurable emissions of any of the compounds, but rather low deposition of acetaldehyde and acetic acid was observed instead. Tree species specific variations in deposition velocities were largely due to variations in stomatal conductance. Flooding of the roots resulted in leaf emissions of ethanol and acetaldehyde by all species, while emissions of acetic acid were only observed from the species exhibiting the highest ethanol and acetaldehyde emission rates. All three compounds showed a similar diurnal emission profile, each displaying an emission burst in the morning, followed by a decline in the evening. This concurrent behavior supports the conclusion, that all three compounds emitted by the leaves are derived from ethanol produced in the roots by alcoholic fermentation, transported to the leaves with the transpiration stream and finally partly converted to acetaldehyde and acetic acid by enzymatic processes. Co-emissions and peaking in the early morning suggest that root ethanol, after transportation with the transpiration stream to the leaves and enzymatic oxidation to acetaldehyde and acetate, is the metabolic precursor for all compounds emitted, though we can not totally exclude other production pathways. Emission rates substantially varied among tree species, with maxima differing by up to two orders of magnitude (25–1700 nmol m−2 min−1 for ethanol and 5–500 nmol m−2 min−1 for acetaldehyde). Acetic acid emissions reached 12 nmol m−2 min−1. The observed differences in emission rates between the tree species are discussed with respect to their root adaptive strategies to tolerate long term flooding, providing an indirect line of evidence that the root ethanol production is a major factor determining the foliar emissions. Species which develop morphological root structures allowing for enhanced root aeration produced less ethanol and showed much lower emissions compared to species which lack gas transporting systems, and respond to flooding with substantially enhanced fermentation rates and a non-trivial loss of carbon to the atmosphere. The pronounced differences in the relative emissions of ethanol to acetaldehyde and acetic acid between the tree species indicate that not only the ethanol production in the roots but also the metabolic conversion in the leaf is an important factor determining the release of these compounds to the atmosphere

Electrochemical detection of in situ adriamycin oxidative damage to DNA

Adriamycin intercalation and in situ interaction with double helix DNA was investigated using a voltammetric DNA-biosensor. Oxidation and reduction of adriamycin molecules intercalated in double helix DNA were investigated in order to understand the in vivo mechanism of action with this anti-neoplasic drug. The results showed that the interaction of adriamycin with DNA is potential-dependent causing contact between DNA guanine and adenine bases and the electrode surface such that their oxidation is easily detected. A mechanism for adriamycin reduction and oxidation in situ when intercalated in double helix DNA immobilised onto the glassy carbon electrode surface is presented and the formation of the mutagenic 8-oxoguanine explained.http://www.sciencedirect.com/science/article/B6THP-44PVS7R-M/1/1474d369a4b1d556b84d548d2df2543

Population structure of Pentaclethra macroloba (Willd.) Kuntze in high and low floodplains of the Amazonian estuary.

The flood cycle of floodplain forests and topographic variations are important factors of diversification and morphological and ecophysiological adaptations of the plant community. Pentaclethra macroloba is a hyperdominant species adapted to flood variations. The objective of this study was to characterize the P. macroloba population structure between environments with high topography, flooded only during the rainy season and peak flood of the river, (high várzea-HV) and low topography with daily flood (low várzea-LV). The study was carried in the Mazagão Experimental Field, Brazil. Four plots of 1 ha were installed in each environment. All individuals with DBH ≥ 5 cm were measured and georeferenced. ANOVA test, 0.05% probability, was applied to verify the structural differences between two environments. The HV had higher population density (51.2 individuals.ha-1) compared to the LV (36.7 individuals.ha-1), although without significance. Basal area was higher in the HV (10.42 m²) in comparison with LV (5.90 m²), with significant difference (F = 7.13, p = 0.00795). The maximum DAP of HV was 67 cm with mean of 24 cm. The LV presented maximum DBH of 42 cm with mean of 21 cm, showing structural difference between the two environments (F = 6.22, p = 0.0131). The aggregation index showed high aggregation in the LV (R = 0.89) than in the HV (R = 0.79), differing significantly between the two environments (F = 11.31, p = 0.0008). Frequency and time of flooding are ecological drives that structure the population of pracaxizeiro causing morphological and ecophysiological adaptations to the individual

Diagnóstico fitossanitário em sementes de cedro e tachi branco.

O trabalho objetivou diagnosticar fitopatógenos presentes em sementes de cedro vermelho (Cedrela odorata L.) e tachi branco (Sclerolobium paniculatum Vogel), espécies florestais nativas da Amazônia. A importância da patologia de sementes relaciona-se com a disseminação de doenças pelo fruto quando este é levado para beneficiamento e para evitar o apodrecimento das sementes, o que pode ocasionar perda pela presença de fitopatógenos nas mesmas. Os testes foram feitos com base nas Regras de Análise de Sementes (RAS) do Ministério da Agricultura, Pecuária e Abastecimento ? MAPA, pelo método de incubação em papel filtro ?Blotter Test?. Foram detectados os seguintes gêneros de fungos: Aspergillus sp., Penicillium spp. e Lasiodiplodia sp. em sementes de cedro e Penicillium spp. e Aspergillus sp. em tachi branco. As sementes de cedro apresentaram maiores níveis de incidência de fungos.PIBIC-2011

Cervical nodular fasciitis in a 10-year-old girl: a case report of a rare condition

Nodular fasciitis (NF) is a benign fibroblastic proliferation that usually involves  superficial fascia in the subcutaneous tissue or muscle. The rapid growth, high  cellularity and mitotic activity can simulate sarcoma. Thus, as clinical and morphologic characteristics are similar to those of malignant tumours, this entity is often  misdiagnosed, with a few cases described in the literature. We present a case of nodular fasciitis involving the retropharynx and hypopharynx of a 10-year-old girl and discuss the importance of considering this rare diagnosis in different soft tissue masses.Keywords: excisional biopsy, histology, nodular fasciiti

Reflection on Risk Factors, Ashtma and Tobacco Smoke Exposure

O impacto da asma brônquica nas últimas décadas, nomeadamente em idade pediátrica, associando prevalências significativas a uma tendência, gravidade e custos crescentes, tem levado a que se efectuem múltiplos estudos para esclarecer causas, avaliando riscos, permitindo a elaboração de programas de prevenção. Estudos epidemiológicos bem desenhados, aplicados a amostras populacionais significativas, permitem identificar determinantes independentes da asma, viabilizando a actuação. Se muito se tem avançado no conhecimento das bases fisiopatológicas da doença alérgica, é com alguma preocupação que sentimos que a comunidade médica, mesmo a especializada, não sente as evidências epidemiológicas como aplicáveis à sua população de asmáticos. “Precisamos de mais estudos”, é declaração comum. Com este trabalho, centrado em três rastreios efectuados com a coordenação dos autores, pretendemos demonstrar que existem factores preveníveis, moduláveis, que podem permitir reduzir a morbilidade da doença asmática. Entre estes, o tabagismo passivo assume uma relevância ímpar, por ser o principal factor de risco para a gravidade da asma pediátrica em Portugal

Synthesis of new donor/acceptor 5-cyclopentadienyl and 5-indenyliron(II) complexes with p-benzonitrile derivatives. Crystal structures of [Fe( 5-C5H5)(CO)(P(OC6H5)3)(p-NCC6H4NO2)][BF4]·CH2Cl2 and [Fe( 5-C9H7)(CO)(P(OC6H5)3)(p-NCC6H4NO2)][BF4]

New complexes of the type [Fe( 5-Cp or Ind)(L)(L )(p-NCR)][BF4] (L, L =CO, P(OC6H5)3, P(C6H5)3; R=C6H4N(CH3)2, C6H4NO2, (E)-C(H) C(H)C6H4NO2, (E)-C(H) C(H)C6H4N(CH3)2) have been synthesised and characterised. Spectroscopic data were analysed in order to evaluate the tuning of the electronic density at the metal centre and the extension of the -delocalisation on the molecule, due to the presence of coligands with different acceptor/donor abilities. The structures of two complexes [Fe( 5-C5H5)(CO)(P(OC6H5)3)(p-NCC6H4NO2)][BF4] and [Fe( 5-C9H7)(CO)(P(OC6H5)3)(p-NCC6H4NO2)][BF4] were determined by X-ray crystallographic analysis. The compounds crystallised in the centrosymmetric space groups P1 and P21/n, respectively. Bond distances within the nitrile ligand are discussed in order to evaluate the nature of iron–nitrile bonding in these complexes

Electron microprobe analysis of cryolite

Comunicação apresentada em: EMAS 2013 : 13th European Workshop on Modern Developments and Applications in Microbeam Analysis, Centro de Congressos da Alfândega do Porto, Portugal, 12 to 16 May 2013A sample of cryolite was studied with a JEOL JXA 8500-F electron microprobe under several operating conditions. A TAP crystal was used to analyse Na and Al and a LDE1 crystal to analyse F. As F and Na are both highly "volatile" elements, special care must be taken during analysis. The measurement order of Na, F and Al is not irrelevant and optimum conditions may also result in different combinations of accelerating voltage, beam current, beam size or counting times. Relevant X-ray signals were recorded in order to investigate the behaviour of the Na Ka and F Ka counts with elapsed time. The incident beam current was also recorded at the same time. In a clear contrast to what has normally been reported in the EPMA analysis of aluminosilicates and silicate glasses, we found that the Na X-ray counts increase with time. This increment of X-rays intensities for sodium in cryolite depends on the operating conditions and is accompanied by a strong migration of fluorine from the beam excitation volume, leading to a decrease in F X-ray counting rates. It was also observed that higher incident beam currents induce higher radiation damage in the mineral. The current instability is consistent with possible electron induced dissociation in the cryolite structure. An analytical protocol was achieved for 6 kV and 15kV accelerating voltage for the correct EPMA analysis of cryolite