Eficácia do glyphosate e 2,4-D no controle de Commelina villosa

O objetivo do presente trabalho foi avaliar a eficácia de glyphosate e 2,4-D, isolados e em mistura, no controle de Commelina villosa. Foram estudadas duas metodologias de avaliação de absorção de herbicidas em oito intervalos de tempo para a lavagem (simulando chuva após a aplicação) e corte (simulando abortamento, como estratégia de defesa) das folhas: 2, 4, 6, 8, 12, 24 e 48 horas após a aplicação dos herbicidas, além de um tratamento sem lavagem ou corte das folhas, em delineamento experimental inteiramente casualizado com quatro repetições, dispostos em um esquema fatorial 3 x 7 + 1 (três herbicidas x sete períodos - horas após a aplicação). Os herbicidas e doses testados foram: glyphosate (1.440 g ha-1), 2,4-D (720 g ha-1) e a mistura glyphosate + 2,4-D (1.080 + 720 g ha-1). A simulação de chuva interferiu de forma negativa no controle das plantas com o herbicida glyphosate. O controle com o herbicida 2,4-D foi influenciado apenas no período de 2 horas. Os períodos de simulação de chuva não influenciaram no controle das plantas com a mistura de glyphosate + 2,4-D. Para o estudo com corte das folhas tratadas, todos os tratamentos independente do período para corte das folhas foram influenciados de forma negativa no controle, sendo que as plantas apresentaram rebrotas quando tratadas com o herbicida 2,4-D isolado.

Doença pulmonar obstrutiva crônica e fatores associados em São Paulo, SP, 2008-2009

OBJETIVO: Estimar a prevalência e fatores associados à doença pulmonar obstrutiva crônica. MÉTODOS: Estudo transversal, de base populacional com 1.441 indivíduos de ambos os sexos e com 40 anos de idade ou mais no município de São Paulo, SP, entre 2008 e 2009. As informações foram coletadas por meio de entrevistas domiciliares e os participantes foram selecionados a partir de amostragem probabilística, estratificada por sexo e idade, e por conglomerados em dois estágios (setores censitários e domicílios). Foi realizada regressão múltipla de Poisson na análise ajustada. RESULTADOS: Dos entrevistados, 4,2% (IC95% 3,1;5,4) referiram doença pulmonar obstrutiva crônica. Após análise ajustada, identificaram-se os seguintes fatores independentemente associados ao agravo: número de cigarros fumados na vida (> 1.500/nenhum) RP = 3,85 (IC95%: 1,87;7,94), cansar-se com facilidade (sim/não) RP = 2,61 (IC95% 1,39;4,90), idade (60 a 69 anos/50 a 59 anos) RP = 3,27 (IC95% 1,01;11,24), idade (70 anos e mais/50 a 59 anos) RP = 4,29 (IC95% 1,30;14,29), problemas de saúde nos últimos 15 dias (sim/não) RP = 1,31 (IC95% 1,02;1,77), e atividade física no tempo livre (sim/não) RP = 0,57 (IC95% 0,26;0,97). CONCLUSÕES: A prevalência da doença pulmonar obstrutiva crônica é elevada e está associada ao uso do tabaco e idade acima de 60 anos. Os problemas de saúde freqüentes e redução da atividade física no tempo livre podem ser considerados conseqüências dessa doença.

Prevalência de asma e fatores associados: estudo de base populacional em São Paulo, SP, 2008-2009

OBJETIVO: Estimar a prevalência de asma em crianças e adolescentes e identificar fatores associados. MÉTODOS: Estudo transversal de base populacional com 1.185 crianças e adolescentes de ambos os sexos de São Paulo, SP, de 2008 a 2009. As informações foram coletadas por meio de entrevistas domiciliares e os participantes foram selecionados a partir de amostragem probabilística, estratificada por sexo e idade, e por conglomerados em dois estágios (setores censitários e domicílios). Foi realizada regressão múltipla de Poisson na análise ajustada entre o desfecho e variáveis sociodemográficas, econômicas, estilo de vida e condições de saúde. RESULTADOS: Dos entrevistados, 9,1% (IC95% 7,0;11,7) referiram asma. Após análise ajustada, identificaram-se os seguintes fatores independentemente associados ao agravo: idade (zero a quatro anos/15 a 19) RP = 3,18 (IC95% 1,20;8,42), idade (cinco a nove anos/15 a 19) RP = 6,37 (IC95% 2,64;15,39), idade (10 a 14 anos/15 a 19) RP = 4,51 (IC95% 1,95;10,40), alergia (sim/não) RP = 2,22 (IC95% 1,24;4,00), rinite (sim/não) RP = 2,13 (IC95% 1,22;3,73), problemas de saúde nos 15 dias prévios à entrevista (sim/não) RP = 1,96 (IC95% 1,23;3,11), número de cômodos no domicílio (1 a 3/4 e mais) RP = 1,67 (IC95% 1,05;2,66), e cor da pele (preta e parda/branca) RP = 2,00 (IC95% 1,14;3,49). CONCLUSÕES: Os achados do presente estudo apontam a importância da asma associada à presença de rinite e alergia, idade entre cinco e nove anos, cor da pele preta e parda e moradia com menor número de cômodos. Os frequentes problemas de saúde podem ser considerados consequência dessa doença.

Twentyfold blue upconversion emission enhancement through thermal effects in Pr3+/Yb3+-codoped fluoroindate glasses excited at 1.064 mu m

Infrared-to-visible upconversion emission enhancement through thermal effects in Yb3+-sensitized Pr3+-doped fluoroindate glasses excited at 1.064 mu m is investigated. A twentyfold increase in the 485 nm blue emission intensity as the sample temperature was varied from 20 to 260 degrees C was observed. The visible upconversion fluorescence enhancement is ascribed to the temperature dependent multiphonon-assisted anti-Stokes excitation of the ytterbium sensitizer and excited-state absorption of the praseodymium acceptor. A model based upon conventional rate equations considering a temperature dependent effective absorption cross section for the F-2(7/2)-->F-2(5/2) transition of the Yb3+ and (1)G(4)-->P-3(0) excited-state absorption of the Pr3+, agrees very well with the experimental results. (C) 2000 American Institute of Physics. [S0021-8979(00)08209-8].

Red-green-blue upconversion emission and energy-transfer between Tm3+ and Er3+ ions in tellurite glasses excited at 1.064 mu m

Red, green, and blue emission through frequency upconversion and energy-transfer processes in tellurite glasses doped with Tm3+ and Er3+ excited at 1.064 mum is investigated. The Tm3+/Er3+-codoped samples produced intense upconversion emission signals at around 480, 530, 550 and 660 nm. The 480 nm blue emission was originated from the (1)G(4)-->H-3(6) transition of the Tm3+ ions excited by a multiphoton stepwise phonon-assisted excited-state absorption process. The 5 30, 5 50 nm green and 660 mn red upconversion luminescences were identified as originating from the H-2(11/2), S-4(3/2) --> I-4(15/2) and F-4(9/2) --> I-4(15/2) transitions of the Er3+ ions, respectively, populated via efficient cross-relaxation processes and excited-state absorption. White light generation employing a single infrared excitation source is also examined. (C) 2003 Elsevier B.V. (USA). All rights reserved.

Linear readout of dynamic phase modulation index in an optical voltage sensor using the new J(1) ... J(3) spectral method

The J(1)...J(3) is a recent optical method for linear readout of dynamic phase modulation index in homodyne interferometers. In this work, the J(1)... J(3) method is applied to measure voltage in an optical voltage sensor. Based on the classical J(1)...J(4) method, the J(1)... J(3) technique shows to be more stable to phase drift and simpler for implementation than the original one. The sensor dynamic range is enhanced. The agreement between theoretical and experimental results, based on 1/f noise, is demonstrated.

Differential antagonism by conotoxin p-TIA of contractions mediated by distinct alpha(1)-adrenoceptor subtypes in rat vas deferens, spleen and aorta

The ability of the conotoxin p-TIA, a 19-amino acid peptide isolated from the marine snail Conus tulipa, to antagonize contractions induced by noradrenaline through activation of alpha(1A)-adrenoceptors in rat vas deferens, alpha(1B)-adrenoceptors in rat spleen and alpha(ID)-adrenoceptors in rat aorta, and to inhibit the binding of [I-125]HEAT (2-[[beta-(4-hydroxyphenyl)ethyl]aminomethyl]-1-tetralone) to membranes of human embryonic kidney (HEK) 293 cells expressing each of the recombinant rat alpha(1)-adrenoceptors was investigated. p-TIA (100 nM to 1 muM) antagonized the contractions of vas deferens and aorta in response to noradrenaline without affecting maximal effects and with similar potencies (pA(2)similar to7.2, n=4). This suggests that p-TIA is a competitive antagonist of alpha(1A)- and alpha(1D)-adrenoceptors with no selectivity between these subtypes. Incubation of p-TIA (30 to 300 nM) with rat spleen caused a significant reduction of the maximal response to noradrenaline, suggesting that p-TIA is a non-competitive antagonist at alpha(1B)-adrenoceptors. After receptor inactivation with phenoxybenzamine, the potency of p-TIA in inhibiting contractions was examined with similar occupancies (similar to25%) at each subtype. Its potency (pIC(50)) was 12 times higher in spleen (8.3 +/- 0.1, n=4) than in vas deferens (7.2 +/- 0.1, n=4) or aorta (7.2 0.1, n=4). In radioligand binding assays, p-TIA decreased the number of binding sites (B,,,,,,) in membranes from HEK293 cells expressing the rat alpha(1B)-adrenoceptors without affecting affinity (K-D), In contrast, in HEK293 cells expressing rat alpha(1A)- or alpha(1D)-adrenoceptors, p-TTA decreased the KD without affecting the B-max. It is concluded that p-TIA will be useful for distinguishing the role of particular alpha(1)-adrenoceptor subtypes in native tissues. (C) 2004 Elsevier B.V. All rights reserved.

Efficient energy upconversion emission in Tm3+/Yb3+-codoped TeO2-based optical glasses excited at 1.064 mu m

Efficient energy upconversion of cw radiation at 1.064 mum into blue, red, and near infrared emission in Tm3+-doped Yb3+-sensitized 60TeO(2)-10GeO(2)-10K(2)O-10Li(2)O-10Nb(2)O(5) glasses is reported. Intense blue upconversion luminescence at 485 nm corresponding to the Tm3+ (1)G(4)--> H-3(6) transition with a measured absolute power of 0.1 muW for 800 mW excitation power at room temperature is observed. The experimental results also revealed a sevenfold enhancement in the upconversion efficiency when the sample was heated from room temperature to 235 degreesC yielding 0.7 muW of blue absolute fluorescence power for 800 mW pump power. High brightness emission around 800 nm (F-3(4)--> H-3(6)) in addition to a less intense 655 nm ((1)G(4)--> H-3(4) and F-3(2,3)--> H-3(6)) fluorescence is also recorded. The energy upconversion excitation mechanism for thulium emitting levels is assigned to multiphonon-assisted anti-Stokes excitation of the ytterbium-sensitizer followed by multiphonon-assisted sequential energy-transfer processes. (C) 2001 American Institute of Physics.

Electroluminescence of a device based on europium beta-diketonate with phosphine oxide complex

Rare earth (RE) ions have spectroscopic characteristics to emit light in narrow lines, which makes RE complexes with organic ligands candidates for full color OLED (Organic Light Emitting Diode) applications. In particular, beta-diketone rare earth (RE(3+)) complexes show high fluorescence emission efficiency due to the high absorption coefficient of the beta-diketone and energy transfer to the central ion. In this work, the fabrication and the electroluminescent properties of devices containing a double and triple-layer OLED using a new beta-diketone complex, [Eu(bmdm)(3)(tppo)(2)], as transporting and emitting layers are compared and discussed. The double and triple-layer devices based on this complex present the following configurations respectively: device 1: ITO/TPD (40 nm)/[Eu(bmdm)(3)(tppo)(2)] (40 nm)/Al (150 nm); device 2: ITO/TPD (40 nm)/[Eu(bmdm)(3) (tppo)(2)] (40 nm)/Alq(3) (20 nm)/Al (150 nm) and device 3: ITO/TPD (40 nm)/bmdm-ligand (40 nm)/Al (150 nm), were TPD is (N,N'-diphenyl-N,N'-bis(3-methylphenyl)-1,1-biphenil-4,4-diamine) and bmdm is butyl methoxy-dibenzoyl-methane. All the films were deposited by thermal evaporation carried out in a high vacuum system. These devices exhibit high intensity photo- (PL) and electro-luminescent (EL) emission. Electroluminescence spectra show emission from Eu(3+) ions attributed to the (5)D(0) to (7)F(J) (J = 0, 1, 2, 3 and 4) transitions with the hypersensitive (5)D(o) -> (7)F(2) transition (around 612 nm) as the most prominent one. Moreover, a transition from (5)D(1) to (7)F(1) is also observed around 538 nm. The OLED light emission was almost linear with the current density. The EL CIE chromaticity coordinates (X = 0.66 and Y = 0.33) show the dominant wavelength, lambda(d) = 609 nm, and the color gamut achieved by this device is 0.99 in the CIE color space. (c) 2006 Elsevier B.V. All rights reserved.

Epstein-Barr virus (EBV) nuclear antigen (EBNA)-4 mutation in EBV-associated malignancies in three different populations

Different ethnic groups with a high human leukocyte antigen (HLA)-A11 prevalence have been shown to experience a high rate of Epstein-Barr virus (EBV) infection, EBV-associated malignancies, and Epstein-Barr nuclear antigen (EBNA)-4 mutations. The epitopes 393-408 and 416-424 of EBNA-4 are major antigenic epitopes that elicit an HLA-A11 cytotoxic T lymphocyte (CTL) response to EBV infection. Mutations selectively involving one or more nucleotide residues in these epitopes affect the antigenicity of EBNA-4, because the mutant EBV strains are not recognized by the HLA-A11-restricted CTLs. To investigate these mutations in common EBV-associated malignancies occurring in different populations, we studied the mutation rate of epitopes 393-408 and 416-424 of EBNA-4 in 25 cases of EBV-associated Hodgkin's disease (HD), nine cases of AIDS-related non-Hodgkin's lymphoma, and 37 cases of EBV-associated gastric carcinoma (GC) from the United States, Brazil, and Japan. We found one or more mutations in these two epitopes in 50% (6/12) of United States HD, 15% (2/13) of Brazilian HD, 50% (6/12) United States GC and 28% (7/25) Japanese GC, and 22% (2/9) of United States AIDS-lymphoma. Similar mutations were found in 30% (3/10) of United States reactive, 0% (0/6) of Brazilian reactive, and 25% (2/8) Japanese reactive tissues. The most frequent amino acid substitutions were virtually identical to those seen in previously reported isolates from EBV-associated nasopharyngeal carcinomas and Burkitt's lymphomas occurring in high prevalence HLA-A11 regions. However, only 2/28 (7%) mutations occurred in HLA-A11-positive patients. Our studies suggest that: 1) EBNA-4 mutations are a common phenomenon in EBV-associated HD, GC, and AIDS-lymphoma; 2) the mutation rate does not vary in these geographic areas and ethnic groups; 3) EBNA-4 mutations in EBV-associated United States and Brazilian HD, United States and Japanese GC, and United States AIDS lymphomas are not related to patients' HLA-A11 status.

Low voltage electroluminescence of terbium- and thulium-doped zinc oxide films

Strong interest in developing technology for visual information. stimulates research for thin film electroluminescent devices. Here, for the first time, we report that thulium- and terbium-doped zinc-oxide films are suitable for electroluminescence applications. Two different devices were assembled as lTO/LiF/ZnO:RE/LiF/Al or ITO/SiO2/ZnO:RE/SiO2/Al, where ZnO:RE is a film of zinc oxide containing 10 at% of Tb3+ or Tm3+. Electroluminescence spectra show that besides a broad emission band with maximum around 650 nm assigned to ZnO, also emission lines from Tb3+ at 484 nm (D-5(4) -> F-7(6)), 543 nm (D-5(4) -> F-7(6)), and 589 nm (D-5(4) -> F-7(4)), or from Tm3+ at 478 nm ((1)G(4) -> H-3(6)), and 511 mn (D-1(2) -> H-3(5)) were detected. Intensity of emission as function of applied voltage and current-voltage characteristic are shown and discussed. (c) 2005 Elsevier B.V. All rights reserved.

Application of a Biomimetic Sensor Based on Iron Phthalocyanine Chloride: 4-Methylbenzylidene-Camphor Detection

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Superstrings in graviphoton background and N = 1/2 + 3/2 supersymmetry

Motivated by Ooguri and Vafa, we study superstrings in flat ℝ4 in a constant self-dual graviphoton background. The supergravity equations of motion are satisfied in this background which deforms the M = 2 d = 4 flat space super-Poincaré algebra to another algebra with eight supercharges. A D-brane in this space preserves a quarter of the supercharges; i.e. N = 1/2 supersymmetry is realized linearly, and the remaining N = 3/2 supersymmetry is realized nonlinearly. The theory on the brane can be described as a theory in noncommutative superspace in which the chiral fermionic coordinates θα of N = 1 d = 4 superspace are not Grassman variables but satisfy a Clifford algebra. © SISSA/ISAS 2003.

Conformational basis for the biological activity of TOAC-labeled angiotensin II and bradykinin: Electron paramagnetic resonance, circular dichroism, and fluorescence studies

N-Terminally and internally labeled analogues of the hormones angiotensin (AII, DRVYIHPF) and bradykinin (BK, RPPGFSPFR) were synthesized containing the paramagnetic amino acid 2,2,6,6-tetramethylpiperidine-1-oxyl-4-amino-4- carboxylic acid (TOAC). TOAC replaced Asp 1 (TOAC 1-AII) and Val 3 (TOAC 3-AII) in AII and was inserted prior to Arg 1 (TOAC 0-BK) and replacing Pro 3 (TOAC 3-BK) in BK. The peptide conformational properties were examined as a function of trifluoroethanol (TFE) content and pH. Electron paramagnetic resonance spectra were sensitive to both variables and showed that internally labeled analogues yielded rotational correlation times (TC) considerably larger than N-terminally labeled ones, evincing the greater freedom of motion of the N-terminus. In TFE, τ C increased due to viscosity effects. Calculation of τ Cpeptide/τ CTOAC ratios indicated that the peptides acquired more folded conformations. Circular dichroism spectra showed that, except for TOAC 1-AII in TFE, the N-terminally labeled analogues displayed a conformational behavior similar to that of the parent peptides. In contrast, under all conditions, the TOAC 3 derivatives acquired more restricted conformations. Fluorescence spectra of All and its derivatives were especially sensitive to the ionization of Tyr 4. Fluorescence quenching by the nitroxide moiety was much more pronounced for TOAC 3-AII The conformational behavior of the TOAC derivatives bears excellent correlation with their biological activity, since, while the N-terminally labeled peptides were partially active, their internally labeled counterparts were inactive [Nakaie, C. R., et al., Peptides 2002, 23, 65-70]. The data demonstrate that insertion of TOAC in the middle of the peptide chain induces conformational restrictions that lead to loss of backbone flexibility, not allowing the peptides to acquire their receptor-bound conformation. © 2004 Wiley Periodicals, Inc.

Flow evolution of a metallic slurry during thixoextrusion of an automotive valve

The aim of this work is to characterize a metallic slurry (Al-4.5%Cu) flow during thixoforming of an automotive valve. The necessary globular structure was obtained by first inoculating the alloy with TIBAL (5%Ti, 1%B, Al - rest) at 750.0°C, and then reheating to a state between liquidus and solidus prior to thixoforming. Two metallic slurries, with a solid phase of approximately 86.1 and 78.2 percent, were used to generate different experimental flow patterns during the thixoforming process. The flow of the material into the die was observed for total, and partial displacement (2.7, 5.4, 7.5mm) of the punch. The first displacement shows formation of the valve rod. The patterns at each step of displacement of the punch were preserved by quenching in water, thus revealing the profile of the die fill and microstructural evolution. Degeneration of the globular phase was observed along the piece thixoextruded. Thixoextrusion forces versus time curves were generated for partial and full displacement of the punch. Porosity was visible along the billet prior to thixoforming. However, some areas show that the porosity gradually decreased to zero as the thixoextrusion pressure increased. Turbulent, transient and laminar flow are analyzed in this work.