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101.
Molecular Mechanism of Action of 2‐Ferrocenyl‐1,1‐diphenylbut‐1‐ene on HL‐60 Leukemia Cells 下载免费PDF全文
Dr. Alane Cabral de Oliveira Emanuella Gomes da Silva Dr. Danilo Damasceno Rocha Dr. Elizabeth A. Hillard Dr. Pascal Pigeon Prof. Gérard Jaouen Felipe A. R. Rodrigues Prof. Fabiane C. de Abreu Dr. Fabrícia da Rocha Ferreira Prof. Marilia O. F. Goulart Prof. Letícia V. Costa‐Lotufo 《ChemMedChem》2014,9(11):2580-2586
The aim of this work was to investigate the mechanism of action of 2‐ferrocenyl‐1,1‐diphenylbut‐1‐ene ( 1 ) on HL‐60 human leukemia cells. While inactive against noncancerous cells, 1 provoked a concentration‐dependent decrease in viable tumor cells, primarily via apoptosis, as evidenced by analysis of cell morphology, activation of caspases 3 and 7, increased DNA fragmentation, and externalization of phosphatidylserine. Necrosis was observed only at the highest tested concentration (4 μM ). Compound 1 interfered with the cell cycle, causing an accumulation of cells in the G1/G0 phase. Interaction of 1 with dsDNA and ssDNA was observed by differential pulse voltammetry and confirmed by hyperchromicity in the UV/Vis spectra of dsDNA, with an interaction constant of 2×104 M ?1. Both the organic analogue 1,1,2‐triphenylbut‐1‐ene ( 2 ) and ferrocene were inactive against cancer and noncancer cell lines and did not react with DNA. These results reinforce the idea that the hybrid strategy of conjugating ferrocene to the structure of tamoxifen derivatives is advantageous in finding new substances with antineoplastic activity. 相似文献
102.
A comparative study of farm nutrient budgets and nutrient flows of certified organic and non-organic farms in China,Brazil and Egypt 总被引:3,自引:0,他引:3
Myles Oelofse Henning Høgh-Jensen Lucimar S. Abreu Gustavo F. Almeida Ahmed El-Araby Qiao Yu Hui Andreas de Neergaard 《Nutrient Cycling in Agroecosystems》2010,87(3):455-470
Increased demand for certified organic products has led to an increase in the number of certified organic farms in developing
countries. Knowledge of farmer nutrient management practices on certified organic farms in developing countries is limited.
Thus, the aim of this study was to investigate the impact of the adoption of certified organic agriculture on farm nutrient
flows and nutrient budgets, and evaluate to which degree organic farms comply with organic principles relating to nutrient
management. The study is based on five case studies of different types of certified organic farming systems in Brazil, Egypt
and China. Farm nutrient flows and nutrient budgets for nitrogen, phosphorous and potassium were created for each farm. Four
of the five organic systems studied had nutrient surpluses on the farm budget. The surpluses were of varying magnitude. The
main difference between organic and non-organic farm nutrient flows was the replacement of mineral fertilizers with organic
inputs. However, the magnitude of nutrient flows were generally similar for organic and non-organic farms. Certified organic
farms with positive nutrient budgets had a heavy reliance on external inputs. Continued high dependence on an external supply
of nutrients, which typically originate from mineral sources, poses a significant challenge to organic farmers’ fulfilment
of the principles of organic agriculture. 相似文献
103.
Steady-state vapor intrusion scenarios involving aerobically biodegradable chemicals are studied using a three-dimensional multicomponent numerical model. In these scenarios, sources of aerobically biodegradable chemical vapors are placed at depths of 1-14 m beneath a 10 m x 10 m basement or slab-on-grade construction building, and the simultaneous transport and reaction of hydrocarbon and oxygen vapors are simulated. The results are presented as Johnson and Ettinger attenuation factors alpha (predicted indoor air hydrocarbon concentration/source vapor concentration), and normalized contour plots of hydrocarbon and oxygen concentrations. In addition to varying the vapor source depth, the effects of source concentration (2-200 mg chemical/L vapor) and oxygen-limited first-order reaction rates (0.018-1.8 h(-1)) are studied. Hydrocarbon inputs were specific to benzene, although the relevant properties are similar to those for a range of hydrocarbons of interest. Overall, the results suggest that aerobic biodegradation could play a significant role in reducing vapor intrusion into buildings (decreased alpha-values) relative to the no-biodegradation case, with the significance of aerobic biodegradation increasing with increasing vapor source depth, decreasing vapor source concentration, and increasing first-order biodegradation rate. In contrast to the no-biodegradation case, differences in foundation construction can be significant in some settings. The significance of aerobic biodegradation is directly related to the extent to which oxygen is capable of migrating beneath the foundation. For example, in the case of a basement scenario with a 200 mg/L vapor source located at 3 m bgs, oxygen is consumed before it can migrate beneath the foundation, so the attenuation factors for simulations with and without aerobic biodegradation are similar for all first-order rates studied. For the case of a 2 mg/L vapor source located at 8 m bgs, the oxygen is widely distributed beneath the foundation, and the attenuation factor for the biodegradation case ranges from about 3 to 18 orders-of-magnitude less than that for the no-biodegradation case. 相似文献
104.
Enhanced performance of HFCVD nanocrystalline diamond self-mated tribosystems by plasma pretreatments on silicon nitride substrates 总被引:1,自引:0,他引:1
C.S. Abreu M. Amaral F.J. Oliveira A.J.S. Fernandes J.R. Gomes R.F. Silva 《Diamond and Related Materials》2006,15(11-12):2024
Nanocrystalline diamond (NCD) coatings were grown by the hot-filament chemical vapour deposition (HFCVD) method on hydrogen plasma pretreated silicon nitride (Si3N4) substrates. The friction and wear behaviour of self-mated NCD films, submitted to unlubricated sliding and high applied loads (up to 90 N), was assessed using an oscillating ball-on-flat configuration in ambient atmosphere. The reciprocating tests revealed an initially high friction coefficient peak, associated to the starting surface roughness of NCD coatings (Rq = 50 nm). Subsequently, a steady-state regime with low friction coefficient values (0.01–0.04) sets in, related to a smoother (Rq = 17 nm) tribologically modified surface. A polishing wear mechanism governing the material loss was responsible for mild wear coefficients (k 10− 7 mm3 N− 1 m− 1). The hydrogen etching procedure notably increased the film adhesion with respect to untreated surfaces as demonstrated by the high threshold loads (60 N; 3.5 GPa) prior to film delamination. 相似文献
105.
Abreu E Quiroz-Rothe E Mayoral AI Vivo JM Robina A Guillén MT Agüera E Rivero JL 《Meat science》2006,74(2):359-372
To investigate the effects of the reproductive background (nuliparous/primiparous) on skeletal muscle phenotype and their interaction with two alternative finishing systems (indoors/outdoors) in Iberian sows, 32 contemporary piglets were assigned to four different groups: indoors-nuliparous, indoors-primiparous, outdoors-nuliparous and outdoors-primiparous. Nuliparous sows were ovariectomized at 4 months of age, whereas primiparous were castrated at 14 months of age, after their first lactation. Indoors sows were fattened (2 months prior to slaughter) intensively, whereas outdoors sows were finished in an extensive land with natural resources. Muscle samples (semimembranosus, gluteobiceps) were analyzed for myosin fibre types and fibre sizes. Sows finished out-of-doors had more type I and IIA fibres and smaller fibres than indoor-fattened pigs. Primiparous reared indoors had a significantly lower IIX:IIB fibre ratio and showed a clear tendency for having larger fibres than nuliparous reared indoors. Reproductive background effect interacted with rearing condition effect inducing relevant muscular adaptations. Thus, the influence of reproductive background on muscle characteristics was not significant in sows reared out-of-doors but highly significant in sows finished intensively. This interaction resulted in muscular traits less favourable for meat quality in primiparous vs. nuliparous reared indoors. 相似文献
106.
107.
Howell S.E.L. Yackel J.J. De Abreu R. Geldsetzer T. Breneman C. 《Geoscience and Remote Sensing, IEEE Transactions on》2005,43(6):1338-1350
The thermodynamic state of sea ice is important to accurately and remotely monitor in order to provide improved geophysical variable parameterizations in sea ice thermodynamic models. Operationally, monitoring the thermodynamic state of sea ice can facilitate eased ship navigation routing. SeaWinds/QuikSCAT (QuikSCAT) dual-polarization [i.e., horizontal (HH) and vertical (VV)] active microwave data are available at a sufficiently large spatial scale and high temporal resolution to provide estimates of sea ice thermodynamics. This analysis evaluated the temporal evolution of the backscatter coefficient (/spl sigma//spl deg/) and VV/HH copolarization ratio from QuikSCAT for estimating sea ice thermodynamics. QuikSCAT estimates were compared against RADARSAT-1 synthetic aperture radar (SAR) imagery and the Canadian Ice Service (CIS) prototype operational ice strength algorithm. In situ data from the Collaborative Interdisciplinary Cryospheric Experiment (C-ICE) for 2000, 2001, and 2002 were used as validation. Results indicate that the temporal evolution of /spl sigma//spl deg/ from QuikSCAT is analogous to RADARSAT-1. The QuikSCAT /spl sigma//spl deg/ temporal evolution has the ability to identify winter, snow melt, and ponding thermodynamic states. Moreover, the copolarization VV/HH ratio of QuikSCAT could provide a second estimate of the ponding state in addition to identifying the drainage state that is difficult to detect by single-polarization SAR. QuikSCAT detected thermodynamic states that were found to be in reasonable agreement to that of in situ observations at the C-ICE camp for all years. Operational implications of this analysis suggest QuikSCAT is a more effective and efficient medium for monitoring ice decay compared to RADARSAT-1 and can be utilized to provide more robust modeled ice strength thresholds. 相似文献
108.
Igor F. Vasconcelos Sérgio S. M. Tavares F. Evaristo U. Reis Hamilton F. G. Abreu 《Journal of Materials Science》2009,44(1):293-299
The consequences of ageing at 400 and 475 °C on α′ precipitation and corrosion resistance of a novel Cr–Mo ferritic SS with high Mo content were investigated. Combination of X-ray diffraction and Mössbauer spectroscopy results indicates the appearance of a small amount of a paramagnetic phase as a result of the ageing. This phase is iso-structural with the α phase and is thus associated with a Cr-rich α′ phase. The appearance of this phase is related to a decrease of the resistance to corrosion as studied by DL-EPR because the presence of this paramagnetic phase leads to discontinuities in the oxide layer thus reducing corrosion protection and exposing the steel to the action of the corrosive solution. 相似文献
109.
José Eugenio Lopes de Almeida Paulo Márcio da Silveira José Policarpo Gonçalves de Abreu Hector Arango 《Electric Power Systems Research》2009
This paper presents the development of new time-domain equations related to the definition of apparent power. These equations are compatible with the IEEE Std 1459-2000 Standard. When the application of these formulations involves an adequate quantity of samples, thus obeying the Nyquist Criterion, they can be utilized without restrictions regarding distortion, imbalance and asymmetry. Thus, they may be used in numeric meters for power measurements. In addition, unlike the above-mentioned standard, they do not oversimplify with respect to the phase and neutral resistance ratio or the percentage of delta-connected and wye-connected loads. 相似文献
110.
B.J. Gonçalves C.G. Pereira A.M.T. Lago C.S. Gonçalves T.M.O. Giarola L.R. Abreu J.V. Resende 《Journal of dairy science》2017,100(5):3513-3525
This study aimed to evaluate the rheological behavior and thermal conductivity of dairy products, composed of the same chemical components but with different formulations, as a function of temperature. Subsequently, thermal conductivity was related to the apparent viscosity of yogurt, fermented dairy beverage, and fermented milk. Thermal conductivity measures and rheological tests were performed at 5, 10, 15, 20, and 25°C using linear probe heating and an oscillatory rheometer with concentric cylinder geometry, respectively. The results were compared with those calculated using the parallel, series, and Maxwell-Eucken models as a function of temperature, and the discrepancies in the results are discussed. Linear equations were fitted to evaluate the influence of temperature on the thermal conductivity of the dairy products. The rheological behavior, specifically apparent viscosity versus shear rate, was influenced by temperature. Herschel-Bulkley, power law, and Newton's law models were used to fit the experimental data. The Herschel-Bulkley model best described the adjustments for yogurt, the power law model did so for fermented dairy beverages, and Newton's law model did so for fermented milk and was then used to determine the rheological parameters. Fermented milk showed a Newtonian trend, whereas yogurt and fermented dairy beverage were shear thinning. Apparent viscosity was correlated with temperature by the Arrhenius equation. The formulation influenced the effective thermal conductivity. The relationship between the 2 properties was established by fixing the temperature and expressing conductivity as a function of apparent viscosity. Thermal conductivity increased with viscosity and decreased with increasing temperature. 相似文献