A Cheap And Efficient Photochemical Reactor For Chemical Experiments [um Reator Fotoquímico Barato E Eficiente Para Experimentos De Química]

In this work, we present an efficient and inexpensive device for undergraduate chemistry classes aimed at teaching and learning the photolytic synthesis concepts. A photochemical reactor was tested for the synthesis of the organometallic compound enneacarbonyldiiron from iron pentacarbonyl in acetic acid, and its formation evidenced by FTIR analysis. Although similar devices have been described in other studies, none of these offered the simplicity, low cost, class-compatible reaction times and good yields afforded by the procedure reported herein.371164167Yip, W.L., Weyergang, A., Berg, K., Tønnem, H.H., Selbo, P.K., (2007) Mol. Pharmaceutics, 4, p. 241Berg, K., Weyergang, A., Prasmickaite, L., Bonsted, A., Høgset, A., Strand, M.T., Wagner, E., Selbo, P.K., (2010) Methods Mol. Biol., 635, p. 133Neumann, M.G., Quina, F.H., (2002) Quim. Nova, 25, p. 34Mond, L., Langer, C., (1891) J. Chem. Soc., 59, p. 1090Dewar, J., Jones, H.O., (1905) Proc. R. Soc. A, 76, p. 558Speyer, E., Wolf, M., (1927) Chem. Ber., 60, p. 1424Bitterwolf, T.E., (2004) J. Organomet. Chem., 689, p. 3939De Paoli, M.A., Rodrigues, C.F., (1978) Quim. Nova, 1, p. 16De Paoli, M.A., Jorge, R.A., (1980) Quim. Nova, 3, p. 34Federman Neto, A.F., Freitas, F.C.S., Dias, Jr.C.A.E.N., Vichnewski, V., Bonilha, J.B.S., Borges, A.D.L., (2002) Acta Scientiarum, 24, p. 1591Eisch, J.J., (1965) Organometallic Synthesis, 1, p. 93. , Academic Press: New YorkApostolova, E.S., Tikhonov, A.P., Sendyurev, O.A., (2002) Russ. J. Coord. Chem., 28, p. 38Dias, G.H.M., Morigaki, M.K., (1992) Polyhedron, 11, p. 1629Leadbeater, N., (1999) Coord. Chem. Rev., 188, p. 35Shriver, D.F., Atkins, P.W., Overton, T.L., Rouker, J.P., Weller, M.T., Armstrong, F.A., (2006) Química Inorgânica, , 4a ed., Bookman: Porto AlegreHuheey, J.E., Keiter, E.A., Keiter, R.L., (1993) Inorganic Chemistry: Principles of Structure and Reactivity, , 4th ed., Harper Collins: New YorkTeixeira, Z., Vasconcellos, S.P., Koike, L., Dias, G.H.M., (2007) Quim. Nova, 30, p. 494Oliveira, G.M., (2002) Quim. Nova, 25, p. 648Sheline, R.K., Pitzer, K.S., (1950) J. Am. Chem. Soc., 72, p. 1107Sheline, R.K., (1951) J. Am. Chem. Soc., 73, p. 1615Albini, A., Germani, L., (2010) Em Handbook of Synthetic Photochemistry, , Albini, A.Fagononi, M., eds.Wiley-VCH: Weinheim, cap

The Effects of Tropical Vegetation On Rainfall

Vegetation modifies land-surface properties, mediating the exchange of energy, moisture, trace gases, and aerosols between the land and the atmosphere. These exchanges influence the atmosphere on local, regional, and global scales. Through altering surface properties, vegetation change can impact on weather and climate. We review current understanding of the processes through which tropical land-cover change (LCC) affects rainfall. Tropical deforestation leads to reduced evapotranspiration, increasing surface temperatures by 1–3 K and causing boundary layer circulations, which in turn increase rainfall over some regions and reduce it elsewhere. On larger scales, deforestation leads to reductions in moisture recycling, reducing regional rainfall by up to 40%. Impacts of future tropical LCC on rainfall are uncertain but could be of similar magnitude to those caused by climate change. Climate and sustainable development policies need to account for the impacts of tropical LCC on local and regional rainfall

Antibacterial activity of indole alkaloids from Aspidosperma ramiflorum

We evaluated the antibacterial activities of the crude methanol extract, fractions (I-V) obtained after acid-base extraction and pure compounds from the stem bark of Aspidosperma ramiflorum. The minimum inhibitory concentration (MIC) was determined by the microdilution technique in Mueller-Hinton broth. Inoculates were prepared in this medium from 24-h broth cultures of bacteria (10(7) CFU/mL). Microtiter plates were incubated at 37ºC and the MICs were recorded after 24 h of incubation. Two susceptibility endpoints were recorded for each isolate. The crude methanol extract presented moderate activity against the Gram-positive bacteria B. subtilis (MIC = 250 µg/mL) and S. aureus (MIC = 500 µg/mL), and was inactive against the Gram-negative bacteria E. coli and P. aeruginosa (MIC > 1000 µg/mL). Fractions I and II were inactive against standard strains at concentrations of <=1000 µg/mL and fraction III displayed moderate antibacterial activity against B. subtilis (MIC = 500 µg/mL) and S. aureus (MIC = 250 µg/mL). Fraction IV showed high activity against B. subtilis and S. aureus (MIC = 15.6 µg/mL) and moderate activity against E. coli and P. aeruginosa (MIC = 250 µg/mL). Fraction V presented high activity against B. subtilis (MIC = 15.6 µg/mL) and S. aureus (MIC = 31.3 µg/mL) and was inactive against Gram-negative bacteria (MIC > 1000 µg/mL). Fractions III, IV and V were then submitted to bioassay-guided fractionation by silica gel column chromatography, yielding individual purified ramiflorines A and B. Both ramiflorines showed significant activity against S. aureus (MIC = 25 µg/mL) and E. faecalis (MIC = 50 µg/mL), with EC50 of 8 and 2.5 µg/mL for ramiflorines A and B, respectively, against S. aureus. These results are promising, showing that these compounds are biologically active against Gram-positive bacteria

Alterações morfológicas de tecido laminar do casco e parâmetros clínicos e laboratoriais de equinos com síndrome cólica letal Morphologic alterations of the hoof lamellar tissue, and clinic and laboratorial analyses of horses with lethal colic syndrome

As afecções gastrintestinais dos cavalos são agravadas por complicações como a laminite, cuja etiopatogenia está relacionada à degradação da membrana basal do tecido laminar por metaloproteinases (MMPs). A ativação das MMPs pode ocorrer devido à liberação local de citocinas inflamatórias ou enzimas provenientes de leucócitos infiltrados no tecido laminar. O objetivo deste trabalho foi avaliar as alterações morfológicas do tecido laminar de equinos com síndrome cólica letal e sua provável associação com parâmetros clínicos e laboratoriais. Observou-se intensa destruição da arquitetura laminar, principalmente nos animais com alterações físicas e laboratoriais mais acentuadas, como tempo de preenchimento capilar prolongado (TPC), membranas mucosas congestas, taquicardia, hemoconcentração e redução nas contagens de plaquetas e leucócitos. Os resultados sinalizam o provável momento do desenvolvimento de lesões do tecido laminar em equinos com síndrome cólica, no qual é possível adotar medidas preventivas contra a laminite.<br>The gastrointestinal diseases of horses are aggravated by complications such as laminitis. The laminitis etiopathogeny are connected with lamellar basement membrane degradation by matrix metalloproteinases (MMPs). Inflammatory cytokines and leukocytes enzymes can active MMPs. The object of this study was to evaluate morphological changes on lamellar tissue of horses with colic syndrome and its association with clinical and laboratorial parameters. It was observed intensive destruction of lamellar architecture, mainly on animals with severe physical and laboratorial alterations, such as delayed capillary refill time, congested mucous membrane, tachycardia, hemoconcentration and low count of platelet and leukocytes. The results sign to the most likely moment of development of lamellar tissue injuries in horses with colic syndrome, which can be adopted preventive measures against laminitis

Efeitos de Fatores Ambientais na Reprodução de Tartarugas Environmental factors effects in turtles reproduction

Para as espécies de tartaruga que apresentam a determinação sexual dependente da temperatura da incubação o local e o momento da desova, exercem influências que vão além da definição do sexo dos embriões. A influência do local da desova se estende a todo o desenvolvimento embrionário afetando o comportamento e o tamanho dos filhotes. O momento em que ocorre a desova trará conseqüências ao ambiente térmico dos ninhos à medida que a temperatura e a umidade variam ao longo do ano. A umidade será decisiva nas trocas hídricas e gasosas entre os ovos e o meio afetando a absorção do vitelo e o crescimento dos embriões. As cheias e os alagamentos são importantes fatores de perda de ninhos nas espécies de tartaruga de água doce. A desova no momento adequado possibilita uma incubação segura, sem a interferência de alagamentos dos ninhos e conseqüente morte dos embriões. A predação dos ninhos varia de acordo com o local da desova, o tipo e a abundância de predadores e a profundidade da câmara de ovos. A escolha de pontos de desova no interior da vegetação, onde a taxa de predação é geralmente menor, nem sempre é a estratégia mais frequentemente adotada pelas tartarugas, uma vez que esse procedimento pode levar a uma maior exposição das fêmeas aos predadores, à diminuição do sucesso da eclosão ou a alterações na razão sexual provocadas por diferenças na temperatura da incubação.<br>Turtle species in which the sex determination is dependent of incubation temperature, the nest site and the laying moment will affect more than embryo sex determination. The influence of the laying site extends all over the embryonic development, affecting hatching weight and size. The time of the egg-laying will bring consequences to the nest thermal environment, as the temperature and humidity change throughout the year. The humidity will be decisive in gaseous and hydric exchanges between eggs and the environment, affecting yolk absorption and embryo growth. Floods and inundation are important factors related to nest loss in freshwater turtle species. Egg laying at the appropriated time makes a safe incubation possible, without the interference of nest inundation and subsequent embryo death. The nest predation varies according to the egg-laying site, type and abundance of predator and nest depth. The choice of areas in the middle of vegetation, where the predation rate is generally smaller, is not always the most used strategy by turtles, since this procedure can decrease the hatching success or provoke changes in sex ratio