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91.
L. A. Fernández C. Hernández M. Bataller E. Véliz A. López O. Ledea S. Padrón 《Water and Environment Journal》2010,24(3):174-180
Cyclophosphamide is a hazardous cytostatic drug, which should be removed from wastewaters before disposals. Ozonation slowly inactivates this substance, requiring long reaction times to obtain degradation. In this paper, different advanced oxidation processes (AOPs) are studied for cyclophosphamide oxidative degradation in aqueous medium: ozone at several basic pH values, ozone/hydrogen peroxide at neutral and basic pHs with the addition of the peroxide at the beginning of ozonation. The influence of ozone concentration in the gas phase and gas flow is also discussed. Results show that, under the experimental conditions studied, the radical mechanism acting in the AOPs rapidly degrades cyclophosphamide. Additionally, second-order rate constants kd and kOH were determined for direct (molecular) and indirect (radical) reactions. Finally, reactions were carried out with the aim of isolating and identifying some of the degradation products. From ozonation at pH 9, 4-ketocyclophosphamide was identified as the main reaction product. 相似文献
92.
93.
Mayra Anton Dib Saleh Renato de Cássio Ferreira Neves Fábio Arlindo Silva Paula Martin de Moraes Vanessa Rosa Loureiro Paulo dos Santos Roldan Pedro de Magalhães Padilha 《Food Analytical Methods》2009,2(2):162-168
This paper presents a simple, fast, and sensitive method to determine zinc in samples of feces and fish feed by electrothermal
atomic absorption spectrometry through the direct introduction of slurries of the samples into the spectrometer’s graphite
tube. The procedure is based on the injection of 10 μL of an acidified aqueous solution containing 0.50% w/v of feces or feed and 0.50% v/v HNO3 into graphite tube. The limits of detection and quantification calculated for 20 readings of the blank of the standard slurries
(0.50% w/v of feces or feed devoid of zinc) were 0.04 and 0.13 μg L−1 for the standard feces slurries and 0.05 and 0.17 μg L−1 for the standard feed slurries. The proposed method was applied in studies of digestibility of zinc in different fish feeds,
and their results proved compatible with that obtained from samples mineralized by acid digestion using microwave oven. 相似文献
94.
R Bataller JM Nicolás P Ginès A Esteve M Nieves G?rbig E Garcia-Ramallo M Pinzani J Ros W Jiménez AP Thomas V Arroyo J Rodés 《Canadian Metallurgical Quarterly》1997,113(2):615-624
BACKGROUND & AIMS: Hepatic stellate cells (HSCs) are perisinusoidal cells believed to participate in the regulation of hepatic blood flow because of their contractile properties and presence of receptors for several vasoactive factors. It is unknown whether HSCs have receptors for vasopressin, one of the most potent endogenous vasoconstrictors. This study investigated the existence of receptors for and the effects of arginine vasopressin (AVP) on cultured human HSCs. METHODS: intracellular calcium concentration ([Ca2+]i) and cell contraction were measured in individual cells loaded with fura-2 using a morphometric method with an epifluorescence microscope coupled to a CCD imaging system (Photometrics, Tucson, AZ). AVP-specific binding was measured with [3H]AVP. Mitogen-activated protein kinase (MAPk) activity and DNA synthesis were measured by in vitro phosphorylation of myelin basic protein and [3H]thymidine incorporation, respectively. Parallel experiments were performed in vascular smooth muscle cells. RESULTS: AVP elicited a dose-dependent increase in [Ca2+]i and contraction of HSCs. Moreover, AVP increased MAPk activity, DNA synthesis, and cell number. These effects were similar to those observed in vascular smooth muscle cells and were blocked by a V1 receptor antagonist. The existence of V1 receptors was further confirmed by binding studies. CONCLUSIONS: Human HSCs have V1-vasopressin receptors that induce effects similar to those observed in vascular smooth muscle cells. AVP may play a role in the regulation of HSC function. 相似文献
95.
Mayra Montecillo-Aguado Belen Tirado-Rodriguez Gabriela Antonio-Andres Mario Morales-Martinez Zhen Tong Jun Yang Bruce D. Hammock Rogelio Hernandez-Pando Sara Huerta-Yepez 《International journal of molecular sciences》2022,23(11)
Lung cancer is currently the leading cause of cancer death worldwide; it is often diagnosed at an advanced stage and bears poor prognosis. It has been shown that diet is an important environmental factor that contributes to the risk and mortality of several types of cancers. Intake of ω-3 and ω-6 PUFAs plays an important role in cancer risk and progression. Current Western populations have high consumption of ω-6 PUFAs with a ratio of ω-6/ω-3 PUFAs at 15:1 to 16.7:1 This high consumption of ω-6 PUFAs is related to increased cancer risk and progression. However, whether a diet rich in ω-6 PUFAs can contribute to tumor aggressiveness has not been well investigated. We used a murine model of pulmonary squamous cell carcinoma to study the aggressiveness of tumors in mice fed with a diet rich in ω-6 PUFAs and its relationship with oxylipins. Our results shown that the mice fed a diet rich in ω-6 showed a marked increase in proliferation, angiogenesis and pro-inflammatory markers and decreased expression of pro-apoptotic proteins in their tumors. Oxylipin profiling revealed an upregulation of various pro-tumoral oxylipins including PGs, HETEs, DiHETrEs and HODEs. These results demonstrate for the first time that high intake of ω-6 PUFAs in the diet enhances the malignancy of tumor cells by histological changes on tumor dedifferentiation and increases cell proliferation, angiogenesis, pro-inflammatory oxylipins and molecular aggressiveness targets such as NF-κB p65, YY1, COX-2 and TGF-β. 相似文献
96.
Fabrizio Croccolo Cédric Giraudet Henri Bataller Roberto Cerbino Alberto Vailati 《Microgravity science and technology》2016,28(4):467-475
In a fluid system driven out of equilibrium by the presence of a gradient, fluctuations become long-ranged and their intensity diverges at large spatial scales. This divergence is prevented by vertical confinement and, in a stable configuration, by gravity. Gravity and confinement also affect the dynamics of non-equilibrium fluctuations (NEFs). In fact, small wavelength fluctuations decay diffusively, while the decay of long wavelength ones is either dominated by buoyancy or by confinement. In normal gravity, from the analysis of the dynamics one can extract the diffusion coefficients as well as other transport properties. For example, in a thermodiffusion experiment one can measure the Soret coefficient. Under microgravity, the relaxation of fluctuations occurs by diffusion only and this prevents the determination of the Soret coefficient of a binary mixture from the study of the dynamics. In this work we propose an innovative self-referencing optical method for the determination of the thermal diffusion ratio of a binary mixture that does not require previous knowledge of the temperature difference applied to the sample. The method relies on the determination of the ratio between the mean squared amplitude of concentration and temperature fluctuations. We investigate data from the GRADFLEX experiment, an experiment flown onboard the Russian satellite FOTON M3 in 2007. The investigated sample is a suspension of polystyrene polymer chains (MW=9,100g/mol, concentration 1.8wt %) in toluene, stressed by different temperature gradients. The use of a quantitative shadowgraph technique allows to perform measurements in the absence of delicate alignment and calibration procedures. The statics of the concentration and temperature NEFs are obtained and their ratio is computed. At large wave vectors the ratio becomes constant and is shown to be proportional to the thermal diffusion ratio of the sample. 相似文献