Transition metal catalyzed element–element′ additions to alkynes

The efficient and stereoselective synthesis of, or precursors to, multi-substituted alkenes has attracted substantial interest due to their existence in various industrially and biologically important compounds. One of the most atom economical routes to such alkenes is the transition metal catalyzed hetero element–element′ π-insertion into alkynes. This article provides a thorough up-to-date review on this area of chemistry, including discussions on the mechanism, range of Esingle bondE′ bonds accessible and the stoichiometric/catalytic transition metal mediators employed

Biogas production: litter from broilers receiving direct-fed microbials and an enzyme blend

ABSTRACT The effect of additives used in the feed of broilers on anaerobic bio-digestion of poultry litter was evaluated. Four diets were used: NC: negative control; DFM: NC + 500 ppm direct-fed microbials (DFM) containing Bacillus subtilis and Bacillus licheniformis; ENZ: diet formulated with an enzyme blend (20 ppm phytase, 200 ppm protease and 200 ppm xylanase); DFM+E: ENZ + DFM. Substrates for the anaerobic bio-digestion were prepared with litter from each treatment, containing 4 % total solids (TS). These were used in 16 continuous bio-digesters with a 2 kg d−1 load, to determine the production and potential biogas production and composition during an 85-day period. Influent and effluent samples were collected for the amounts of TS and volatile solids (VS), fiber fraction (neutral detergent fiber [NDF], acid detergent fiber [ADF] and lignin), nutrients (N, P and K), and total and thermotolerant coliforms to be determined. For all treatments a reduction in the following effluents was observed as follows: TS (49, 48, 48 and 50 %) VS (70, 54, 55 and 62 %) NDF (91, 90, 95 and 96 %) ADF (89, 88, 93 and 94 %) and lignin (80, 76, 89 and 88 %). The efficiency of the treatment for coliforms in bio-digesters was higher than 90 % in the 85-day period in all treatment groups. There was a reduction in biogas and methane production when DFM (5500 and 4000 mL) and DFM + E (5800 and 4100 mL) were used, compared to treatments NC (6300 mL and 4400) and ENZ (6400 and 4500 mL). The potential production of reduced TS and VS was higher in ENZ (1:00 and 1.74 106 mL kg−1) when compared to NC (0.88 and 1:02 106 mL kg−1), DFM (0.80 and 1:40 106 mL kg−1) and DFM + E (0.88 1:25 and 106 mL kg−1). The additives did not affect the percentage of methane production, and all treatments showed values higher than 70 %. Adding enzymes to the diet of broilers influences the litter characteristics and, as a consequence, increases biogas production. The addition of DFM and DFM + E to broiler diets reduced biogas and methane production

Southern African Large Telescope Spectroscopy of BL Lacs for the CTA project

In the last two decades, very-high-energy gamma-ray astronomy has reached maturity: over 200 sources have been detected, both Galactic and extragalactic, by ground-based experiments. At present, Active Galactic Nuclei (AGN) make up about 40% of the more than 200 sources detected at very high energies with ground-based telescopes, the majority of which are blazars, i.e. their jets are closely aligned with the line of sight to Earth and three quarters of which are classified as high-frequency peaked BL Lac objects. One challenge to studies of the cosmological evolution of BL Lacs is the difficulty of obtaining redshifts from their nearly featureless, continuum-dominated spectra. It is expected that a significant fraction of the AGN to be detected with the future Cherenkov Telescope Array (CTA) observatory will have no spectroscopic redshifts, compromising the reliability of BL Lac population studies, particularly of their cosmic evolution. We started an effort in 2019 to measure the redshifts of a large fraction of the AGN that are likely to be detected with CTA, using the Southern African Large Telescope (SALT). In this contribution, we present two results from an on-going SALT program focused on the determination of BL Lac object redshifts that will be relevant for the CTA observatory

Co-digestão dos dejetos de suínos e óleo vegetal de descarte: adição de microrganismos e lipases comercias

The objective of the implementation of this work the study on the recommended levels of disposal of oil addition to swine manure as well as the influence of the inclusion of lipase levels or Biol®, in order to evaluate the effect of increased production of biogas, methane and reduction of solids. Two steps were conducted, the first with respect to recommended levels of oil addition and using the second oil levels that were negative effect on lipase or Biol® added. For assay development co-digestion of the first stage substrates were prepared containing 4% total solids (TS), composed of swine manure disposal of oil (in the ratios of 0, 2, 4, 6, 8, 10 and 12 %) addition of water for dilution of this waste and inoculum to supply batch digesters. For development of the second stage was performed supply of batch digesters with substrates containing 4% TS, composed of swine manure disposal of oil (in the ratios of 8, 10 and 12%), lipase (in the proportions of 0.05; 0.10, 0.15, 0.20 and 0.25%) or Biol® (10 g/m3 to 15 g/m3) than water for dilution of these residues and inoculum. Regarding the influence of the oil addition levels found that the maximum TS and VS reductions were 36.8 and 41.1% and occurred at levels of 5.2% oil and 5.8 to substrates, the additions of 5.4 and 6.1% enabled the oil potential range of 222.9 and 263.6 liters of biogas per kg TS and VS added. Referring to influence of adding oil and lipase was found that reductions of TS and VS were 56.13 and 64.49% and were in inclusion levels of 0.15 and 0.13% lipase and 12% of oil added to the substrates and that the greatest potential of methane production per g of TS and volatile solids (VS) added (0.23 and 0.29 liters) were achieved by greater inclusion of oil (12%) was added when the levels of 0.12 and 0.11% lipase. Regarding the inclusion of Biol®, it was found that the higher potential production of methane per g TS and VS added (0.22 and 0.27 liters, respectively) were ...Objetivou-se com a execução deste trabalho o estudo a respeito dos níveis recomendados de inclusão de óleo de descarte aos dejetos de suínos bem como a influencia da inclusão de níveis de lipase ou Biol®, com o intuito de avaliar o efeito do acréscimo de produção de biogás, metano e redução dos teores de sólidos. Foram realizadas duas etapas, sendo a primeira a respeito dos níveis recomendados de adição de óleo e a segunda utilizando os níveis de óleo que apresentaram efeito negativo adicionados à lipase ou Biol®. Para desenvolvimento do ensaio de co-digestão da primeira etapa foram preparados substratos contendo 4% de sólidos totais (ST), compostos por dejetos de suínos, óleo de descarte (nas proporções de 0, 2, 4, 6, 8, 10 e 12%) além de água para diluição destes resíduos e inóculo, para abastecimento de biodigestores batelada. Para desenvolvimento da segunda etapa foi realizado abastecimento de biodigestores batelada com substratos contendo 4% de ST, compostos por dejetos de suínos, óleo de descarte (nas proporções de 8, 10 e 12%), lipase (nas proporções de 0,05; 0,10; 0,15; 0,20 e 0,25%) ou Biol® (10 g/m3 ou 15 g/m3) além de água para diluição destes resíduos e inoculo. Com relação a influencia da adição de níveis de óleo verificou-se que as máximas reduções de ST e SV foram de 36,8 e 41,1% e ocorreram nos níveis de 5,2 e 5,8% de óleo aos substratos, as inclusões de 5,4 e 6,1% de óleo permitiram o alcance de potenciais de 222,9 e 263,6 litros de biogás por kg de ST e SV adicionados. Referindo-se a influencia da adição de níveis de óleo e lipase verificou-se que as reduções máximas de ST e SV foram de 56,13 e 64,49% e ocorreram nos níveis de inclusão 0,15 e 0,13% de lipase e 12% de óleo adicionado aos substratos e ainda que os maiores potenciais de produção de metano por g de ST e sólidos voláteis (SV) adicionados (0,23 e 0,29 litros) foram alcançados pela ..

Potencial bromatológico do capim Piatã cultivado em sistema orgânico

O objetivo do trabalho foi verificar o potencial bromatológico do capim Piatã cultivado em sistema orgânico. O experimento foi conduzido em casa de vegetação adotando-se delineamento inteiramente casualizado em esquema fatorial com parcela subdividida no tempo. As parcelas foram compostas por seis tratamentos: dois tipos de compostos (cama de frango a base de cana de açúcar ou capim napier) e três doses (100, 200 e 300 kg.ha-1 equivalente N) e as subparcelas foram cinco períodos de corte. Os compostos foram aplicados em dose única, após o corte de uniformização, nas doses de 100, 200 e 300 kg.ha-1 de N. Foi observado efeito dos períodos de corte, uma vez que as plantas produzidas no verão apresentaram valor nutritivo superior as de inverno. Os teores de fibra em detergente neutro, fibra em detergente ácido, celulose, hemicelulose e lignina apresentaram comportamento linear negativo em função das doses crescentes de nitrogênio. Já os teores de proteína bruta, nutrientes digestíveis totais e os coeficientes de digestibilidade “in vitro” da matéria seca responderam linear e positivamente às doses de nitrogênio. Não foi observada diferença significativa entre os tipos de compostos orgânicos e na interação compostos orgânicos x dose, o que possibilita a recomendação do uso de ambos os compostos orgânicos, sem que ocorresse prejuízo na qualidade das plantas avaliadas