Electron transfer driven decomposition of adenine and selected analogs as probed by experimental and theoretical methods

We report on a combined experimental and theoretical study of electron transfer induced decomposition of adenine and a selection of analogue molecules in collisions with potassium atoms (K). Time-of-flight negative ion mass spectra have been obtained in a wide collision energy range (6–68 eV in the centre-of-mass frame), providing a comprehensive investigation of the fragmentation patterns of purine, adenine, 9-methyl adenine, 6-dimethyl adenine and 2-D adenine. Following our recent communication about selective hydrogen loss from the transient negative ions (TNI) produced in these collisions [T. Dunha et al. J. Chem. Phys. 148, 021101 (2018)], this work focuses on the production of smaller fragment anions. In the low-energy part of the present range, several dissociation channels that are accessible in free electron attachment experiments are absent from the present mass spectra, notably NH2 loss from adenine and 9-methyl adenine. This can be understood in terms of a relatively long transit time of the K+ cation in the vicinity of the TNI tending to enhance the likelihood of intramolecular electron transfer. In this case, the excess energy can be redistributed through the available degrees of freedom inhibiting fragmentation pathways. Ab initio theoretical calculations were performed for 9-methyl adenine (9-mAd) and adenine (Ad) in the presence of a potassium atom and provided a strong basis for the assignment the lowest unoccupied molecular orbitals accessed in the collision process

Tradução de interfaces de aplicações para idiomas distintos.

Este documento apresenta o esquema de tradução proposto para as telas de entrada de dados do banco de dados de experimentos em manejo de fertilizantes para cana-de-açúcar.bitstream/CNPTIA/10193/1/comtec54.pdfAcesso em: 30 maio 2008

Avaliação do efeito de plantas inseticidas e produtos comerciais sobre folhas de mandioca (Manihot esculenta Crantz).

A mandioca Manihot esculenta Crantz é uma planta rica em carboidratos de grande importância socioeconômica para os estados que a produzem. Cultivada em todo o Brasil devido a sua adaptação às diversas condições edafoclimáticas, no nordeste se destaca por ser utilizada no combate à fome (LIMA, et al. 2012). Durante o ciclo produtivo é atacada por diversos insetos pragas e a utilização de pesticidas encarece a produção e provoca danos ao meio ambiente. Nesse contexto, as plantas inseticidas ressurgem como alternativa para minimizar os impactos provocados pelos agrotóxicos (CARBALI, et al, 2009). Dentre as plantas utilizadas no controle de insetos pragas, tem-se o Chenopodium ambrosioides L. em lepidópteros e coleópteros, o Zingiber officinale Roscoe em afídeos e o Azadirachta indica A. de Jussie que figura-se como a mais importante, devido a sua ação de mortalidade, repelência, fagoinibidor, ainda atua sobre o desenvolvimento de fase jovem dos insetos além de ser seletivo à inimigos naturais (CORRÊA; SALGADO, 2011). No Entanto as plantas inseticidas também apresentam desvantagens, sendo que a fitotoxicidade é pouco estudada (XUAN, et al., 2004). De acordo com Karlsson (2005), a fitotoxicidade é definida como a capacidade de um produto provocar danos temporários ou permanentes a uma planta. As partes mais afetadas pelos extratos de plantas inseticidas são as folhas, causando nas mesmas, necrose no limbo foliar, engruvilhamento, descoloração e redução do tamanho com efeito direto na capacidade de realizar fotossíntese. Dessa forma, o objetivo deste trabalho foi avaliar o efeito de plantas inseticidas Azadirachta indica, Zingiber officinale e Chenopodium ambrosioides e produtos comerciais Azamax® e Organic Neem® sobre folhas de mandiocas Manihot esculenta Crantz

Enhanced SnS phase purity of films produced by rapid thermal processing of SnS2 precursors

In this work, we present a procedure to grow single phase SnS thin films consisting on the annealing of RF magnetron sputtered SnS2 precursors . A series of samples was produced by rapid thermal processing of precursors deposited both on bare and Mo coated glass. For those samples the time at maximum temperature and heating rate were variedN/

Various routes for low temperature RFmagnetron sputtering of Indium Tin Oxide films

In this work we have studied the influence of the Ar working pressure, substrate temperature, low power plasma irradiation and partial pressure of hydrogen in the RF-magnetron sputtering of indium tin oxide (ITO) thin films on glass substrates. This work aims at identifying the best conditions to achieve good quality ITO film at low temperature. Four sets of samples were prepared which were characterized by scanning electron microscopy, X-ray diffraction (XRD), Van der Pauw, transmittance and absorbance measurementsN/

Teor de nutrientes, crescimento e produção de rizomas de açafrão em resposta a adubação nitrogenada.

Este trabalho teve por objetivo avaliar o efeito de doses de nitrogênio (N) sobre acessos de açafrão

Fish and cephalopods associated with the squid Loligo vulgaris Lamarck, 1798 in Portuguese waters

Fish and cephalopod taxa occurring in association with Loligo vulgaris, in Portuguese waters between Lisbon and Vila Real de Santo António, were investigated by sampling with bottom trawling equipment between 1990-1991 and 1993-1995. The family Triglidae, the genera Pagellus and Trachurus and the four species Alloteuthis subulata, Boops boops, Callionymus lyra, and Merluccius merluccius were found, on average, in at least 75% of the trawls with L. vulgaris. Conversely, that cephalopod was found in at least 75% of the trawls with the family Trachinidae, the genera Dentex, Diplodus, Liza and Torpedo and the six species, Hyperoplus lanceolatus, Pagrus pagrus, Pomatoschistus m. minutus, Psetta m. maxima, Scophthalmus rhombus and Spicara flexuosa. An index of "affinity" (ranging from -∞ to 1) between L. vulgaris and the other taxa was used in order to highlight co-occurrences of an unlikely coincidental nature. Lists of taxa with high affinity index scores (0.5 to 1) are given for 5 different situations: all samples together; samples grouped by bottom depth; samples grouped by research cruise; research cruises grouped by season and by year. Pair wise comparisons between all taxa lists for each of the 5 situations were made, indicating a greater influence of depth than any other factor in the composition of the lists. The significance of the degree of similarity between lists of taxa, "preferred" under different circumstances and the reasons for those "preferences" are discussed

Growth and Characterization of single phase SnS thin films by sulphurization of sputtered sulphide precursors

Single-phase SnS thin films have been grown on soda-lime glass substrates based on the sulphurization of RF-magnetron sputtered SnS2 precursors. Two different approaches to sulphurization were compared and thoroughly studied. The two series of identical precursors were sulphurized in the same furnace, inside a graphite box with and without elemental sulphur evaporation. Different maximum sulphurization temperatures, in the range 300ºC to 570ºC, were tested. Sulphurization of SnS2 precursors in a graphite box with and without sulpur vapour at high temperature produces SnS films which appear to be single-phase from the structural analysis. The studies show that the direct absorption transitions of SnS are at 1.41 eV and 1.68 eV for sulphurization in graphite box with and without elemental sulphur evaporation, respectively. The indirect absorption transition values varied from 1.49 eV e 1.37 eV.N/