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da Silva P.P.,Federal University of Alagoas | Soares L.,Federal University of Alagoas | da Costa J.G.,Embrapa Tabuleiros Costeiros | da Silva Viana L.,Institute of Chemistry and Biotechnology | And 11 more authors.
Industrial Crops and Products | Year: 2012

Water deficit is among the main environmental factors limiting agricultural productivity of sugarcane in Northeast Brazil by affecting virtually every aspect of plant growth, with consequent reduction of the agro-industrial productivity of this crop. This study aimed to use path analysis to evaluate the physiological components of sugarcane under two water conditions, with photosynthesis as the basic variable, in order to obtain subsidies that can help the genetic breeding of this crop by selection of superior clones with drought tolerance. The experiment was carried out in a greenhouse with a completely randomized experimental design, 4 × 2 factorial arrangements (four sugarcane genotypes × two soil moisture regimes: control, with 80-100% available water and stressed, with 0-20% water available) and with four replications. Each plot consisted of one pot with 12. kg of substrate containing one plant. Treatments were maintained at a humidity close to field capacity with daily replacement of the evapotranspired water with a water supply for 66 days of cultivation for treatments under stress. Evaluations were conducted on the fourth day after severe water stress at 70 days of cultivation. Data from nine physiological variables were considered, with six of these being used in the model after exclusion of those that were contributing to multicollinearity. Variables used in path analysis were enough to explain the variation found in photosynthesis under both water conditions. Stomatal conductance, transpiration and the SPAD index should be considered as a priority in breeding programs for sugarcane aiming to get more productive and tolerant genotypes to water stress, and selection indexes should be used with due consideration of these variables to promote gains in photosynthesis. © 2011 Elsevier B.V.

De Oliveira C.A.F.,Federal University of Pernambuco | Da Silva F.F.,Federal University of Pernambuco | Malvestiti I.,Federal University of Pernambuco | Malta V.R.D.S.,Institute of Chemistry and Biotechnology | And 4 more authors.
Journal of Solid State Chemistry | Year: 2013

Two new metal-organic frameworks (MOFs) have been synthesized under different hydrothermal conditions and characterized by single-crystal X-ray diffraction, infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy and elemental analysis. Compound 1, crystallized in space group P1 with the formula [Tm 2(L) 3(H 2O) 2]·H 2O, (H 2L=succinic acid), has triclinic cell parameters of a=7.61780(10), b=10.58050(10), c=12.71030(10), α=95.3130(10), β=107.4370(10), γ=111.0960(10) and a cell volume of 888.446(16) Å 3. Compound 2, crystallized in space group I2/a with the same formula, is monoclinic, with cell parameters of a=13.77020(10), b=7.63170(10), c=17.2410(2), β=101.303(10) and a cell volume of 1776.72(3) Å 3. The results of this work indicate that a flexible succinate ligand that provides several modes of coordination can lead to different conformations, depending on the temperature used in the reaction. In the theoretical part of this study, semiempirical quantum chemistry methods using AM1, PM3 and PM6 models are employed to predict the structure of MOFs, calculate the geometric and crystallographic parameters, and make comparisons with experimental data. © 2012 Elsevier Inc. All rights reserved.

De Oliveira C.A.F.,Federal University of Pernambuco | Silva F.F.D.,Federal University of Pernambuco | Malvestiti I.,Federal University of Pernambuco | Malta V.R.D.S.,Institute of Chemistry and Biotechnology | And 4 more authors.
Journal of Molecular Structure | Year: 2013

Two new three-dimensional coordination polymers [Ce2(C 4H4O4)3(H2O) 2]n×H2O 1 and [Yb2(C 4H4O4)3(H2O) 2]n×H2O 2 have been synthesized under hydrothermal conditions and characterized by single-crystal X-ray, elemental, infrared and thermogravimetric analysis. Both compounds crystallized in the monoclinic system and space group C2/c with cell parameters a = 20.1178(2), b = 7.98150(10), c = 14.03090(10), β = 120.9050(10), cell volume = 1933.07(3) Å3 for 1, and a = 19.7360(3), b = 7.59790(10), c = 13.7564(2), β = 121.3060(10), cell volume = 1762.47(4) for 2. The solid-state structures of the two metal-organic frameworks (MOFs) were subjected to detailed analysis using the semiempirical Sparkle/AM1, Sparkle/PM3 and Sparkle/PM6 quantum models. The theoretical results obtained were in good overall agreement with the experimental data, although the Sparkle/PM3 model presented the highest accuracy. The luminescent spectra of 1 and 2 showed emission bands characteristic of the Ce (III) and Yb (III) at 444 nm and 970 nm, respectively. Thermal analysis revealed that both MOFs lost one molecule of water of hydration and two molecules of coordinated water upon heating. In compound 1, the removal of water occurred in two steps while in 2, water loss occurred in a single step. © 2013 Elsevier B.V. All rights reserved.

Jardim G.A.M.,Federal University of Minas Gerais | Reis W.J.,Federal University of Minas Gerais | Ribeiro M.F.,Federal University of Minas Gerais | Ottoni F.M.,Federal University of Minas Gerais | And 8 more authors.
RSC Advances | Year: 2015

In our continued search for novel trypanocidal compounds, arylamine, chalcone, triazolic, triazole-carbohydrate and chalcogenium derivatives containing a naphthoquinone scaffold were prepared; in addition to electrochemical studies, these compounds were evaluated against the infective bloodstream form of Trypanosoma cruzi, the etiological agent of Chagas disease. Among the thirty-eight compounds herein evaluated, six were found to be more potent against trypomastigotes than the standard drug benznidazole, with IC50/24 h values between 52.9 and 89.5 μM. © The Royal Society of Chemistry 2015.

Dos Santos J.B.,Institute of Chemistry and Biotechnology | De Albuquerque N.J.A.,Institute of Chemistry and Biotechnology | De Paiva E Silva Zanta C.L.,Institute of Chemistry and Biotechnology | Meneghetti M.R.,Institute of Chemistry and Biotechnology | Meneghetti S.M.P.,Institute of Chemistry and Biotechnology
RSC Advances | Year: 2015

The catalytic performance of a series of Sn(iv)-based organometallic complexes in fructose conversion was studied under several reaction conditions, and the conversion, yields, and selectivity measurements of this transformation have been evaluated. The results were compared to those obtained from non-catalysed reactions and those in the presence of a conventional catalyst (H2SO4). These organometallic Sn(iv)-based catalysts demonstrated the ability to fully convert fructose into valuable chemicals. Under particular reaction conditions, lactic acid is obtained in good yields and selectivity. © The Royal Society of Chemistry.

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