Darkening of Light

Combined media on paper. 90" x 40", Fire River Series

Eye darkening as a reliable, easy and inexpensive indicator of stress in fish

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Darkening on Lead based pigments: microbiological contribution

The biodeterioration/biodegradation process is an important issue for the conservation of cultural heritage that needs urgent answers to their rehabilitation. In this way, the role of microorganisms in surfaces alteration was exploited. This work revealed a strong relationship between the microbiological proliferation and the damaged areas, evidencing the important role of the microorganisms in mural paintings alteration process. The oxidation of lead-based pigments noticeably contributes to the pigments alteration, and seems to be correlated with the presence of biodeteriorative microorganisms. The study of the mechanisms underlying the microbiological attack of mural paintings has been explored to understand as much as possible the proliferative ability and biodeteriorative capacity of the microorganisms, related to darkening on lead-based pigments

Influência do processo de secagem na qualidade do cogumelo shiitake

Edible mushroom are highly perishable foods. Drying is an alternative to provide safe storage. In this work, the effects of some drying parameters on the quality of Shiitake mushroom were investigated: geometry of the raw material (whole and sliced), drying temperature (50 °C and 70 ºC) and final moisture content (5% and 15% wb). Experimental kinetics of drying was built and color and texture analyses were done in fresh and in rehydrated dried product. The effect of parameters was evaluated by analysis of variance and test of multiple comparisons. Drying kinetics showed that drying happened in falling-rate period and sliced mushroom dried at 70 ºC required lesser drying time than other treatments. Mushroom dried at 70 ºC showed less darkening. Drying time affected mushroom quality, evaluated by great hardness, gummosis and darkening.

Spectroscopic variabilities in lambda Pavonis

Aims. We investigate the time-varying patterns in line profiles, V/R, and radial velocity of the Be star HD 173948 (lambda Pavonis). Methods. Time series analyses of radial velocity, V/R, and line profiles of He I, Fe II, and Si II were performed with the Cleanest algorithm. An estimate of the stellar rotation frequency was derived from the stellar mass and radius in the Roche limit by adopting an aspect angle i derived from the fittings of non-LTE model spectra affected by rotation. The projected rotation velocity, necessary as input for the spectral synthesis procedure, was evaluated from the Fourier transform of the rotation profiles of all neutral helium lines in the optical range. Results. Emission episodes in Balmer and He i lines, as well as V/R cyclic variations, are reported for spectra observed in year 1999, followed by a relatively quiescent phase (2000) and then again a new active epoch (2001). From time series analyses of line profiles, radial velocities, and V/R ratios, four signals with high confidence levels are detected: nu(1) = 0.17 +/- 0.02, nu(2) = 0.49 +/- 0.05, nu(3) = 0.82 +/- 0.03, and nu(4) = 1.63 +/- 0.04 c/d. We interpret nu 4 as a non-radial pulsation g-mode, nu 3 as a signal related to the orbital timescale of ejected material, which is near the theoretical rotation frequency 0.81 c/d inferred from the fitting of the models taken into account for gravity darkening. The signals nu(1) and nu(2) are viewed as aliases of nu(3) and nu(4).

Transiting exoplanets from the CoRoT space mission XII. CoRoT-12b: a short-period low-density planet transiting a solar analog star

We report the discovery by the CoRoT satellite of a new transiting giant planet in a 2.83 days orbit about a V = 15.5 solar analog star (M(*) = 1.08 +/- 0.08 M(circle dot), R(*) = 1.1 +/- 0.1 R(circle dot), T(eff) = 5675 +/- 80 K). This new planet, CoRoT-12b, has a mass of 0.92 +/- 0.07 M(Jup) and a radius of 1.44 +/- 0.13 R(Jup). Its low density can be explained by standard models for irradiated planets.

Discoloration and fungal growth on three fiber cement formulations exposed in urban, rural and coastal zones

Three formulations of fiber cement were evaluated for fungal colonization and color change after five years of exposure in aging stations located in urban (Sao Paulo), rural (Pirassununga) and coastal (Rio Grande) zones in Brazil. The lowest color change and fungal colonization were registered in Rio Grande, which has a temperate climate, as opposed to Sao Paulo and Pirassununga, which are tropical. The highest fungal colonization was recorded in Sao Paulo, one of the most air polluted cities in Brazil. Pirassununga samples had an intermediate fungal colonization, in spite of showing the highest color change with visible dark spots on the surfaces. These spots were identified as cyanobacteria, which significantly contributed to the darkening of the specimens. The fiber cement formulation, varying in proportion of organic fibers such as poly (vinyl alcohol) and cellulose, was less significant for fungal bioreceptivity than the characteristics of the exposure site. The most frequent fungal genus found in the tropical climate, in both urban and rural zones, and the main one responsible for the higher records in Sao Paulo, was Scytalidiurn sp. which was registered for the first time on this building material in Brazil. (C) 2010 Elsevier Ltd. All rights reserved.

Wine industry residues extracts as natural antioxidants in raw and cooked chicken meat during frozen storage

The effect of Isabel (IGE) and Niagara (NGE) grape seed and peel extracts on lipid oxidation, instrumental colour, pH and sensory properties of raw and cooked processed chicken meat stored at -18 degrees C for nine months was evaluated. The pH of raw and cooked samples was not affected by the addition of grape extracts. IGE and NGE were effective in inhibiting the lipid oxidation of raw and cooked chicken meat, with results comparable to synthetic antioxidants. The extracts caused alterations in colour, as evidenced by the instrumental (darkening and lower intensity of red and yellow colour) and sensory results of cooked samples. In the sensory evaluation of odour and flavour, IGE produced satisfactory results, which did not differ from synthetic antioxidants. These findings suggest that the ICE and NGE are effective in retarding lipid oxidation of raw and cooked chicken meat during frozen storage. (c) 2011 Elsevier Ltd. All rights reserved.

Effect of storage time and conditions on the seed coat colour of Australian adzuki beans

Two varieties of adzuki beans (Vigna angularis), Bloodwood and Erimo, were stored at temperatures of 10, 20 or 30degreesC, and relative humidities (RH) 40 or 65%, and samples were analysed at 0, 1.5, 3 and 6 months. Storage at 30degreesC for > 1.5 months caused a significant decrease in the a(star) and b(star) colour values and darkening of the seed coat. Beans stored at 65% RH had lower L-star but higher a(star) and b(star) colour values than those stored at 40% RH. Bloodwood and Erimo samples showed similar trends in colour during storage. The best storage conditions for the preservation of the adzuki colour were 10degreesC and 65% RH. The Australian beans had lower L-star, a(star) and b(star) colour values than Japanese Erimo-shouzu beans and storage increased the difference.

Alterações na estrutura anatômica da madeira de cavacos de eucalyptus grandis em três condições de desfibramento para a confecção de painéis MDF

A utilização da madeira de eucalipto na confecção de painéis MDF é recente, tornando-se necessário entender as modificações em sua estrutura anatômica durante as etapas do processo industrial, notadamente no desfibramento dos cavacos. Com esse objetivo, neste estudo foram aplicadas três condições diferenciadas de desfibramento dos cavacos, alterando-se (i) o tempo de aquecimento, (ii) as pressões de digestão e de desfibramento e (iii) a energia específica de desfibramento, sendo avaliadas as características anatômicas dos componentes celulares da madeira. O aumento da intensidade de refino dos cavacos de madeira reduziu o comprimento médio das fibras e aumentou o porcentual de fibras quebradas, corroborando as imagens de microscopia eletrônica de varredura, além da diminuição do número dos vasos e de células de parênquima. Essa condição de desfibramento mais intensa promoveu, também, um característico escurecimento da coloração da polpa composta pelos elementos celulares da madeira. A aplicação de variáveis de desfibramento mais brandas aumentou a presença de feixes de fibras e do número de vasos e de parênquima, resultando em uma polpa de coloração mais clara. As alterações das características morfológicas dos componentes celulares da madeira dos cavacos de eucalipto, após o tratamento de desfibramento, relacionaram-se com as etapas do processo operacional e com a qualidade tecnológica dos painéis de fibras MDF.

Potencialidades dos extrativos do cerne da madeira de teca como preservativo natural e sua influência na cor de madeiras claras

Este estudo teve como objetivo avaliar o potencial preservativo dos extrativos do cerne da madeira de teca (Tectona grandis) e a capacidade dos mesmos na mudança de coloração de madeiras claras. Para tanto, os resíduos gerados no processamento mecânico do cerne da madeira de teca com 20 anos de idade foram coletados e utilizados para realização de extrações. Para avaliar a influência dos extrativos de teca na cor e resistência natural da madeira foi utilizado o alburno da madeira de teca com 10 anos, além da madeira de Pinus sp., em função de ser uma madeira de coloração clara e baixa resistência natural. Foram realizadas extrações em água quente e etanol absoluto. Para determinação da concentração das soluções de tratamento foi realizado um ensaio de toxidez ao fungo Postia placenta. Após definida a concentração, as soluções extraídas foram preparadas para a impregnação. Além disto, foi utilizada uma terceira solução, composta pela combinação das soluções extraídas em água quente e etanol absoluto. Para cada solução testada foi realizado o tratamento pelo método de célula-cheia (Bethell). Para testar a eficiência das soluções preparadas com extrativos de teca, foram realizados leituras colorimétricas e ensaios biológicos com fungos e térmitas xilófagos. A combinação dos extrativos testados promoveu um escurecimento e reduziu a desuniformidade da cor, fazendo com que as madeiras tratadas se aproximassem mais da cor da madeira de cerne do que das amostras sem tratamento das respectivas espécies. A solução de extrativos obtida em etanol absoluto e a combinação dos extrativos obtidos em água quente e etanol absoluto promoveram os melhores resultados na resistência da madeira tratada contra fungos e térmitas xilófagos, alterando significativamente a classe de resistência das respectivas espécies tratadas.

Postharvest biological control of brown rot in peaches after cold storage preceded by preharvest chemical control 1

ABSTRACT Pathogenic fungi cause skin darkening and peach quality depreciation in post harvest. Therefore, alternative techniques to chemical treatment are necessary in order to reduce risks to human health. The aim of this study was to evaluate the effect of the application of Trichoderma harzianum in association with different fungicides applied before harvest to 'Eldorado' peaches for brown rot control and other quality parameters during storage. The treatments consisted of five preharvest fungicide applications (control, captan, iprodione, iminoctadine and tebuconazole) associated with postharvest application of T. harzianum, after cold storage (with and without application), in three evaluation times (zero, two and four days at 20 °C), resulting in a 5x2x3 factorial design. The application of T. harzianum only brought benefits to the control of brown rot when combined with the fungicide captan, at zero day shelf life. After two days, there was a greater skin darkening in peaches treated with T. harzianum compared with peaches without the treatment, except for peaches treated with the fungicide iprodione and T. harzianum The application of T. harzianum during postharvest showed no benefits for the control of brown rot, however, the association with fungicides reduced the incidence of Rhizopus stolonifer during the shelf life.

Diterpenos de Copaifera reticulata Ducke com atividade larvicida contra Aedes aegypti (L.) (Diptera, Culicidae)

The objective of this study was to evaluate the larvicidal activity of diterpenoids obtained from the oil-resin of Copaifera reticulata against Aedes aegypti larvae, the principal vector of dengue and urban yellow fever. Four diterpenes were obtained from oil-resin extraction with organic solvents and subsequent chromatographic and spectroscopic procedures allowed to isolation and identification of these compounds as 3-b-acetoxylabdan-8(17)-13-dien-15-oic acid (1), alepterolic acid (2), 3-b-hidroxylabdan-8(17)-en-15-oic acid (3), and ent-agatic acid (4). Each compound was previously dissolved in dimethylsulphoxide, and distilled water was added to obtain the desired concentrations. Twenty larvae of third instars were placed into plastic beckers, containing the solution test (25 mL), in a five repetitions scheme, and their mortality, indicated by torpor and darkening of the cephalic capsule, was recorded after 48h. Probit analyses were used to determine lethal concentrations (LC50 and LC90) and their respective 95% confidence intervals. This study showed that only diterpenoids 1 and 2 exhibited larvicidal properties with LC50 of 0.8 ppm and 87.3 ppm, respectively, revealing the former as the most toxic compound against third instars of Ae. aegypti. Therefore, this compound seems to be an interesting source for new metabolite to be exploited.

Larvicidal activity of oil-resin fractions from the Brazilian medicinal plant Copaifera reticulata Ducke (Leguminosae-Caesalpinoideae) against Aedes aegypti (Diptera, Culicidae)

Oil-resin fractions from Copaifera reticulata Ducke (Leguminosae-Caesalpinoideae) were evaluated for larvicidal activity on third larval instars of Aedes aegypti, in searching for alternative control methods for this mosquito. The bioactive fractions were chemically monitored by thin-layer chromatography, ¹H and 13C nuclear magnetic resonance and mass spectrometry. Bioassays were performed using five repetitions, at a temperature of 28 ± 1°C, relative humidity of 80 ± 5% and light and dark cycles of 12h. Mortality was indicated by darkening of the cephalic capsule after 24h of exposure of the larvae to the solutions. The most active fractions were CRM1-4 (sesquiterpenes) and CRM5-7 (labdane diterpenes), which showed LC50 values of 0.2 and 0.8ppm, respectively.

Biological effect of 1-dodecanol in teneral and post-teneral Rhodnius prolixus and Triatoma infestans (Hemiptera: Reduviidae)

Topical application of 1-dodecanol was significantly more toxic against teneral first nymphs (1-3 h old) than post-teneral first nymphs (24 h old). The lethal dose ratios were 711,500 for Rhodnius prolixus and 3613 for Triatoma infestans. No significative difference between LD50 was found when 1-dodecanol was injected in recently hatched adult R. prolixus (1-4 h old) nor in older adults (24 h old). These values were similar to those calculated for deltamethrin (an effective triatomicide), showing that 1-dodecanol had no insecticidal properties when it was applied by injection. Topical application of high dose of 1-dodecanol (1 µg/i) on teneral first nymphs of R. prolixus, produced an interruption of the darkening process of the cuticle, and probably in the development of its physiological properties.