Sample records for fluorine 24
from WorldWideScience.org

Sample records 1 - 2 shown.



1

Efeito da substituição por átomos de flúor no equilíbrio conformacional de chalcona/ Effect of fluorine atom substitution on the conformational equilibrium of chalcone

Cesarin-Sobrinho, Dari; Netto-Ferreira, José Carlos; Braz-Filho, Raimundo
2001-10-01

Resumo em inglês Chalcone (1) and its fluorinated derivatives 2-4, as well as their cyclic analogues 5-10, were synthesized through an aldol condensation reaction between the corresponding ketone and aldehyde. These compounds were characterized by IR, EIMS and ¹H and 13C NMR spectral data. Modern NMR techniques allowed us to conclude that the compounds obtained show E configuration. These techniques were also employed to investigate the equilibrium involving the s-cis and s-trans conform (mais) ations of 1-4, with this equilibrium being dependent on the fluorine substitution on both aromatic rings, A or B. IR studies indicated that the yield of the s-cis conformation in the fluorinated derivatives is 57.4±1.4; 88.1±0.4 and 66.4±0.7%, for 2, 3 and 4, respectively, based on previous ¹H NMR calculations for chalcone. Theoretical calculations, using the MMX method, were employed to justify the variation of chemical shifts for the fluorinated derivatives and cyclic analogues. These chemical shifts are consequence of the anisotropic effect showed by the carbonyl group on these compounds.

Scientific Electronic Library Online (Portuguese)

2

Avaliação nutricional do fósforo disponível de quatro fontes de fósforo para suínos em fase de terminação/ Nutritional evaluation of available phosphorus from four sources for finishing pigs

Veloso, J.A.F.; Medeiros, S.L.S.
1999-10-01

Resumo em português O experimento teve como objetivo avaliar a inclusão de fontes de fósforo (P), considerando-se seu fósforo disponível, sobre o desempenho de suínos em fase de terminação (60 a 100kg). As fontes avaliadas foram: fosfato bicálcico padrão (FBP), fosfato supertriplo (FST), fosfato monoamônio (FMA) e a consorciação de fosfato bicálcico padrão (80%) com o fosfato de Patos de Minas (FPM - 20%). Foram utilizados 32 leitões, machos, castrados, mestiços de raça tipo (mais) carne, com peso médio de 60kg. O delineamento experimental utilizado foi o inteiramente ao acaso, com 4 tratamentos, com 4 repetições de 2 animais cada. As dietas foram isoprotéicas e isoenergéticas adequadas para a fase de terminação. Avaliaram-se o ganho de peso, o consumo de ração, a conversão alimentar e o consumo de flúor. Foram observadas diferenças significativas (P Resumo em inglês The objective of this experiment was to evaluate four phosphorus (P) sources on finishing pigs perfomance from 60 to 100kg weight, considering their available phosphorus. Thirty two castrated male crossbred pigs, were randomly distributed in four treatments with four replications with two animals each. The rations used were isoproteic and isocaloric and the P sources were added to complete 100% of the available P pig requirements, according to the P biological value, prev (mais) iously determined. The P sources were: bicalcium phosphate standard (BPS), triple superphosphate (TSP), monoammonium phosphate (MAP) and the association between 20% Patos de Minas rock phosphate (PMP) and 80% BPS. The parameters analyzed by SNK test were: weight gain, feed consumption, feed conversion and fluorine consumption. Only weight gain and feed consumption were significantly different (P

Scientific Electronic Library Online (Portuguese)