8,545 research outputs found
d-β-Tocotrienol-mediated cell cycle arrest and apoptosis in human melanoma cells
Background: The rate-limiting enzyme of the mevalonate pathway, 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase, provides essential intermediates for the prenylation or dolichylation of growth-related proteins. d-δ-Tocotrienol, a post-transcriptional downregulator of HMG CoA reductase, suppresses the proliferation of murine B16 melanoma cells. Dietary d-δ- tocotrienol suppresses the growth of implanted B16 melanomas without toxicity to host mice. Materials and Methods: The proliferation of human A2058 and A375 melanoma cells following a 72 h incubation in 96-well plates was measured by CellTiter 96® Aqueous One Solution. Cell cycle distribution was determined by flow cytometry. Fluorescence microscopy following acridine orange and ethidium bromide dual staining and procaspase-3 cleavage were used to detect apoptosis. Western-blot was employed to measure protein expression. Results: d-δ-Tocotrienol induced dose-dependent suppression of cell proliferation with 50% inhibitory concentrations (IC50) of 37.5±1.4 (A2058) and 22.3±1.8 (A375) μmol/l, respectively (data are reported as mean±standard deviation). d-δ-Tocotrienol-mediated cell cycle arrest at the G1 phase was accompanied by reduced expression of cyclin-dependent kinase 4. Concomitantly, d- δ-tocotrienol induced caspase-3 activation and apoptosis. The impact of d-δ-tocotrienol on A2058 cell proliferation was potentiated by lovastatin (IC50=3.1±0.5 μmol/l), a competitive inhibitor of HMG CoA reductase. Conclusion: d-δ-Tocotrienol may have potential application in melanoma chemoprevention and/or therapy
UGC 7388: a galaxy with two tidal loops
We present the results of spectroscopic and morphological studies of the
galaxy UGC7388 with the 8.1-m Gemini North telescope. Judging by its observed
characteristics, UGC7388 is a giant late-type spiral galaxy seen almost
edge-on. The main body of the galaxy is surrounded by two faint (\mu(B) ~ 24
and \mu(B) ~ 25.5) extended (~20-30 kpc) loop-like structures. A large-scale
rotation of the brighter loop about the main galaxy has been detected. We
discuss the assumption that the tidal disruption of a relatively massive
companion is observed in the case of UGC7388. A detailed study and modeling of
the observed structure of this unique galaxy can give important information
about the influence of the absorption of massive companions on the galactic
disks and about the structure of the dark halo around UGC7388.Comment: 8 pages, 5 figure
Atributos químicos do solo em sistemas agrossilvipastoris do semiárido cearense com a presença do fogo.
Resumo: A análise dos atributos químicos do solo é uma importante ferramenta para se conhecer a qualidade e as deficiências do solo. Objetivou-se avaliar a fertilidade do solo sob Luvissolo Crômico Órtico e Luvissolo Hipocrômico Órtico em sistema agrossilvipastoril. O presente trabalho foi realizado na Embrapa Caprinos e Ovinos, os sistemas avaliados consistiam de diferentes tipos de manejo: agrosilvipastoril, silvipastoril com queima, silvipastoril sem queima, mata nativa com queima, mata nativa sem queima e sistema tradicional. O delineamento foi inteiramente casualizado em parcelas subdivididas, sendo as parcelas, os manejos e as subparcelas as profundidades (0-0,10 e 0,10-0,20 m); com cinco repetições. Houve diferença significativa nos diferentes manejos para todo os atributos químicos, exceto Mg, Al e V. Os ambientes silvipastoril com e sem queima apresentaram maiores valores para os atributos químicos em relação ao sistema tradicional. Os manejos silvipastoril sem e com queima proporcionaram as maiores concentrações para pH e K; e P, Ca e Na, respectivamente. O manejo agrossilvipastoril apresentou os maiores valores para pH, Na e C.E. Para manta nativa sem e com queima, as maiores concentrações foram para M.O., Ntotal, K, C.E., e adicionalmente para a mata sem queima H+Al. O sistema tradicional apresentou maiores concentrações para Na. A camada superior apresentou maiores valores para pH, M.O., Ntotal, K, CTC e CE em relação a camada 0,10-0,20 m. [Soil chemical properties in agrosylvopasture system at semi-arid northeastern Brazil with presence of fire]. Abstract: The analysis of soil chemical properties is an important tool to know the quality and soil deficiencies. The present study which was conducted at Embrapa Goats e Sheeps had as objective to evaluate soil fertility under Luvisols in agrosilvopasture system in a semi-arid zone. The following treatments were evaluated: agrosilvopasture, burnt silvopasture, non-burnt silvopasture, burnt native forest, non-burnt native forest and traditional. The experimental design was completely randomized block with split plots. The plots, the managements, the subplots and the depths (0-0.10 and 0.10-0.20 m) had five replications. There were significant difference in all treatments for all chemical attributes except Mg, Al and V. The treatments burnt and non-burnt silvopasture and agrosilvopasture showed high values for chemical attributes in relation to the traditional system. The agrosilvopasture environment had higher values for pH, Na and EC. As for burnt and non-burnt native vegetation, both had the highest concentration for MO, Ntotal, K, and EC. Besides, the non-burnt native vegetation had the highest concentration for H+Al. The traditional treatment had high concentration of Na. The top layer had higher values for pH, organic matter, total N, K, CEC and EC compared to 0.10-0.20 m layer
A new method of reconstructing very-high-energy gamma-ray spectra: the Template Background Spectrum
Very-high-energy (VHE, E>0.1 TeV) gamma-ray emission regions with angular
extents comparable to the field-of-view of current imaging air-Cherenkov
telescopes (IACT) require additional observations of source-free regions to
estimate the background contribution to the energy spectrum. This reduces the
effective observation time and deteriorates the sensitivity. A new method of
reconstructing spectra from IACT data without the need of additional
observations of source-free regions is developed. Its application is not
restricted to any specific IACT or data format. On the basis of the template
background method, which defines the background in air-shower parameter space,
a new spectral reconstruction method from IACT data is developed and studied,
the Template Background Spectrum (TBS); TBS is tested on published H.E.S.S.
data and H.E.S.S. results. Good agreement is found between VHE gamma-ray
spectra reported by the H.E.S.S. collaboration and those re-analysed with TBS.
This includes analyses of point-like sources, sources in crowded regions, and
of very extended sources down to sources with fluxes of a few percent of the
Crab Nebula flux and excess-to-background ratios around 0.1. However, the TBS
background normalisation introduces new statistical and systematic errors which
are accounted for, but may constitute a limiting case for very faint extended
sources. The TBS method enables the spectral reconstruction of data when other
methods are hampered or even fail. It does not need dedicated observations of
VHE gamma-ray-free regions (e.g. as the On/Off background does) and circumvents
known geometrical limitations to which other methods (e.g. the reflected-region
background) for reconstructing spectral information of VHE gamma-ray emission
regions are prone to; TBS would be, in specific cases, the only feasible way to
reconstruct energy spectra.Comment: 18 pages, accepted for publication (Astronomy and Astrophysics
Eficiência de fungicidas no controle da mela-das-sementes e do carvão em sementes de Brachiaria brizantha cv. Piatã.
Objetivou-se neste trabalho avaliar a eficiência de fungicidas aplicados na parte aérea das plantas para o controle das referidas doenças em B. brizantha cv. Piatã
Efficacy of zincoderm G cream against wound infection by Pseudomonas aeruginosa in Sprague-Dawley rats
Background: Zincoderm G cream is a fixed dose combination of clobetasol, gentamicin and zinc. Studies have been carried out for efficacy of each component such as clobetasol and gentamicin in bacterial infections, but as fixed dose combination including zinc has not been reported yet. Hence, a study was planned to assess the efficacy of Zincoderm G cream in experimental wound infection by Pseudomonas aerugionosa.Methods: In the experiment a total of 18 Sprague-Dawley rats (male, pathogen free, 6-8 weeks old) were used. The rats were divided into three groups of six rats each. 25-30 mg of test drugs (Zincoderm G cream with or without zinc) was applied on Pseudomonas aeruginosa infected burn wound affected area of back of rats for 2 weeks. Bacterial infection was assessed by quantification of bacteria.Results: There was 80% mortality observed in P. aeruginosa infected toxic control (cream base) group. Whereas, only 40% mortality was seen in both Zincoderm G cream with/without zinc groups, which were inoculated with P. aeruginosa. Bacterial concentration (Number of colony forming unit/ml wound fluid) was significantly decreased (p<0.001) in P. aeruginosa infected rats treated with Zincoderm G cream with zinc when compared with P. aeruginosa infected control (untreated) rats.Conclusions: We found that Zincoderm G cream with zinc exhibited distinct killing profiles against P. aeruginosa
An optimization model for a monopolistic firm serving an environmentally conscious market: Use of Chemical Reaction Optimization Algorithm
This work considers a monopolist firm which faces the following twin challenges of serving an environmentally sensitive market. The first challenge is the demand׳s elasticity to emissions and price. To entice its emission conscious customers and generate higher demand, the firm incrementally invests in cleaner production technologies. It also adopts a voluntary limit on its emissions from transportation. However, such investments and penalty lead to the second challenge of reduced net profit. To address above trade-off, a Non-Linear Programming (NLP) model with a maximization quadratic profit function has been formulated. Recently developed, Chemical Reaction Optimization algorithm, with superior computational performance, has been adopted to solve the NLP. The output of the model provides near optimal monopolistic price, best attainable reduction in manufacturing emissions through proportional investment and makes a choice of suitable mode of transportation for each type of product offered by the firm. Three types of sensitivity analyses were performed by varying contextual parameters: customers׳ emission elasticity, penalty charged per unit emission and investment coefficient. The results, underpin the importance of investments in cleaner technologies and the need of financial aids for profit maximizing firms operating in cleaner markets. This work provides a decision making tool to determine the near optimal degree of each of the above dimension in multiple business fronts
Development of a Bioactive Food Additive for Controlling of Fungal Growth
Fresh foods have a great importance in human nutrition. However, they are marketed with greatly reduced shelf life mainly due to fungal spoilage. In this work, cell wall degrading enzymes produced by Trichoderma asperellum T00 (TCWDE) were immobilized onto cashew gum polysaccharide (CGP) in order to evaluate the potential use of this material as food additive aiming to increase the shelf life by inhibiting fungal growth. Results from factorial design (32) evidenced that the best conditions for TCWDE immobilization was achieved with 20 min of reaction using 1 mmol L-1 of NaIO4. On these conditions it was observed 91% of retention yield for NAGase (30.1 ± 0.38 U mL-1), 41% for chitinase (0.67 ± 0.05 U mL-1), and 24% for β-1,3-glucanase (0.017± 0.001 U mL-1). CGP/TCWDE was effective for growth inhibition of Aspergillus fumigatus and Penicillium sp. and the inhibition mechanism seems to involve changes in the cell wall of those microorganisms. Finally, the CGP/TCWDE presented high stability after drying, maintaining enzymatic and biological activity after 200 days of storage at room temperature (25 ºC)
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