902 resultados para Reverse micelles
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Desalinated brackish groundwater is becoming a new source of water supply to comply with growing water demands, especially in (semi-) arid countries. Recent publications show that some chemical compounds may persist in an unaltered form after the desalination processes and that there is an associated risk of mixing waters with different salinity for irrigation. At the university of Alicante campus (Spain), a mix of desalinated brackish groundwater and water from the existing aquifer is currently applied for landscape irrigation. The presence of 209 emerging compounds, surfactants, priority substances according to the 2008/105/EC Directive, 11 heavy metals and microbiological organisms in blended water and aquifer samples was investigated. Thirty-five compounds were detected (pesticides, pharmaceuticals and surfactants) among them two priority substances α-endosulfan and Ni were found above the permitted maximum concentration. Blended water used for landscape irrigation during the summer period is supersaturated with respect to carbonates, which may ultimately lead to mineral precipitation in the soil-aquifer media and changes in hydraulic parameters.
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Offshore outsourcing of services accelerated at the end of 1990s in developed countries. In recent years, developing countries have also offshored services, not only to developed countries but also to other developing countries. Yet, to date little attention has been paid to the emergence of this reverse offshoring. The focus of this research is on the determinants of reverse offshoring of services; as such we will investigate what drives these firms from developing countries to offshore services.
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Intracellular schizonts of the apicomplexans Theileria annulata and Theileria parva immortalize bovine leucocytes thereby causing fatal immunoproliferative diseases. Buparvaquone, a hydroxynaphthoquinone related to parvaquone, is the only drug available against Theileria. The drug is only effective at the onset of infection and emerging resistance underlines the need for identifying alternative compounds. Current drug assays employ monitoring of proliferation of infected cells, with apoptosis of the infected host cell as a read-out, but it is often unclear whether active compounds directly impair the viability of the parasite or primarily induce host cell death. We here report on the development of a quantitative reverse transcriptase real time PCR method based on two Theileria genes, tasp and tap104, which are both expressed in schizonts. Upon in vitro treatment of T. annulata infected bovine monocytes with buparvaquone, TaSP and Tap104 mRNA expression levels significantly decreased in relation to host cell actin already within 4 h of drug exposure, while significant differences in host cell proliferation were detectable only after 48-72 h. TEM revealed marked alterations of the schizont ultrastructure already after 2 h of buparvaquone treatment, while the host cell remained unaffected. Expression of TaSP and Tap104 proteins showed a marked decrease only after 24 h. Therefore, the analysis of expression levels of mRNA coding for TaSP and Tap104 allows to directly measuring impairment of parasite viability. We subsequently applied this method using a series of compounds affecting different targets in other apicomplexan parasites, and show that monitoring of TaSP- and Tap104 mRNA levels constitutes a suitable tool for anti-theilerial drug development.
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The voltage-dependent anion-selective channel (VDAC) is an intrinsic β-barrel membrane protein located within the mitochondrial outer membrane where it serves as a pore, connecting the mitochondria to the cytosol. The high-resolution structures of both the human and murine VDACs have been resolved by X-ray diffraction and nuclear magnetic resonance spectroscopy (NMR) in 2008. However, the structural data are not completely in line with the findings that were obtained after decades of research on biochemical and functional analysis of VDAC. This discrepancy may be related to the fact that structural biology studies of membrane proteins reveal specific static conformations that may not necessarily represent the physiological state. For example, overexpression of membrane proteins in bacterial inclusion bodies or simply the extraction from the native lipid environment using harsh purification methods (i.e. chaotropic agents) can disturb the physiological conformations and the supramolecular assemblies. To address these potential issues, we have developed a method, allowing rapid one step purification of endogenous VDAC expressed in the native mitochondrial membrane without overexpression of recombinant protein or usage of harsh chaotropic extraction procedures. Using the Saccharomyces cerevisiae isoform 1 of VDAC as a model, this method yields efficient purification, preserving VDAC in a more physiological, native state following extraction from mitochondria. Single particle analysis using transmission electron microscopy (TEM) demonstrated conservation of oligomeric assembly after purification. Maintenance of the native state was evaluated using functional assessment that involves an ATP-binding assay by micro-scale thermophoresis (MST). Using this approach, we were able to determine for the first time the apparent KD for ATP of 1.2 mM.
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Mode of access: Internet.
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Mode of access: Internet.
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Mode of access: Internet.
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Mode of access: Internet.
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Mode of access: Internet.
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Giovanni di ser Giovanni Guidi; D: 3 ft. 1/2 in. (painted surface); tempera, silver, and gold on wood
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Rogier van der Weyden; 11 47/64 in.x 7 63/64 in. (painted surface); oil on wood