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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 55 (1990), S. 0 
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Aluminum uptake studies in viable neuroblastoma cells were performed. Aluminum uptake was largely dependent on the pH of the suspension medium. At physiological pH values, cells were apparently unable to incorporate detectable amounts of aluminum in the absence of proper mediators. Aluminum uptake was enhanced as the pH decreased, attaining a plateau at about pH 6.0. In experiments with 2 × 106 cells/ml, pH 6.0, and 25 μM aluminum in the medium, aluminum incorporation reached saturation at 5 nmol of aluminum/mg of cellular protein, accounting for 60–70% of aluminum added. At pH 6.0, cells showed a large capacity for accumulating aluminum; about 70% of intracellular aluminum was associated with the post-mitochondrial fraction. At neutral pH, application of apotransferrin seemed to facilitate aluminum translocation into cells via membrane receptors. Fatty acids were also capable of mediating aluminum uptake at neutral pH, probably by forming aluminum-fatty acid complexes. Low molecular weight aluminum chelators, e.g., citrate, inhibited aluminum uptake. Treatment of cells with energy metabolism blockers had virtually no influence on aluminum uptake, indicative of passive mechanisms. The results suggest that aluminum uptake occurs via different modes dependent on growth conditions, such as medium pH.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Biochemistry 14 (1975), S. 860-866 
    ISSN: 1520-4995
    Source: ACS Legacy Archives
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Biochemistry 22 (1983), S. 2007-2013 
    ISSN: 1520-4995
    Source: ACS Legacy Archives
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1520-4995
    Source: ACS Legacy Archives
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Cambridge, Mass. : Berkeley Electronic Press (now: De Gruyter)
    Studies in nonlinear dynamics and econometrics 10.2006, 4, art6 
    ISSN: 1081-1826
    Source: Berkeley Electronic Press Academic Journals
    Topics: Mathematics , Economics
    Notes: This study tests whether changes in the short-term interest rate can best be modelled in a non-linear fashion. We argue that there are good theoretical and empirical reasons for adopting this strategy. Using monthly data from several industrialized countries, namely Canada, Germany, Sweden, Switzerland, UK, and US, we show that the short-term interest rate movements are better explained, usually via the exponential smooth transition autoregression (ESTR). Unlike the existing literature on non-linear estimation, we consider a number of candidates for the transition variable. These include: an error correction term, estimated from an underlying cointegrating relationship predicted by the expectations hypothesis, the US term spread, the domestic spread, inflation and output growth forecasts, and deviations from an inflation target in the case of Canada, the UK and Sweden. The sample spans the period from 1960-1998. We reject linearity in the behavior of short-term interest rate changes and instead find support for a non-linear model with the (lagged) domestic spread as the transition variable. However, other more economically meaningful alternatives perform just as well. For example, in the case of the inflation targeting countries in our sample, the most appropriate transition variable can be the deviation from the publicly announced inflation target. We supplement estimates with extensive diagnostic testing of the non-linear model to ensure that we can reject the linear alternative with reasonable confidence. We believe that changes in central bank policies, and in the reaction of market participants over time to such changes, argue in favor of the non-linear estimation approach. We also argue that any model of the term structure estimated over a fairly long span of time necessitates resort to non-linear estimation methods.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Oxford, UK and Boston, USA : Blackwell Publishing Ltd
    Review of international economics 11 (2003), S. 0 
    ISSN: 1467-9396
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Economics
    Notes: The authors investigate the choice of currency of invoicing in international trade under exchange rate fluctuations. Predictions derived from a model developed by Donnenfeld and Zilcha in 1991, and others, regarding the optimal choice of currency of invoice are tested for imports into Canada. The authors employ a unique dataset from Customs Canada that covers a six-year period and lists all currencies used for invoicing by industry. The empirical results support the hypothesis that there is a positive relationship between the extent of invoicing in the importer's national currency and exchange rate risk, and a negative relationship between invoicing in the exporter's currency as well as invoicing in a third currency and exchange rate risk. The empirical results further indicate that relative size of a country plays a role in determining the currency of invoicing.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Journal of the American Chemical Society 92 (1970), S. 5269-5270 
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Journal of agricultural and food chemistry 38 (1990), S. 1494-1497 
    ISSN: 1520-5118
    Source: ACS Legacy Archives
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Journal of agricultural and food chemistry 42 (1994), S. 59-63 
    ISSN: 1520-5118
    Source: ACS Legacy Archives
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Physiologia plantarum 97 (1996), S. 0 
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Short-term uptake and initial localization of aluminium (Al) were investigated in cultured cells of Nicotiana tabacum L. cv. BY-2. Graphite furnace atomic absorption spectrometry and an in vivo Al-sensitive fluorometric assay, employing morin, yielded similar results in all experiments. Aluminium uptake was critically dependent on cell growth. As opposed to negligible uptake in stationary-phase cells, Al uptake (20 μM AlCl3, pH 4.5, 23°C) by actively growing cells was detectable within 5 min, with an initial rate of 16 nmol Al (106 cells)−1 h−1. Increased CaCl2 levels (up to 20 mM), low temperature (4°C), and pre-chelation of Al to citrate greatly reduced Al uptake (by 75–90%). A pH-associated permeabilization of cells at pH 4.5, as monitored by trypan blue, was observed in some growing cells. Although permeability to trypan blue was not a requirement for Al uptake, enhanced membrane permeability at pH 4.5, relative to pH 5.6, may contribute to Al uptake. Aluminium was observed to localize mainly in a pronounced and discrete fluorescent zone at the cell periphery (2–30 μm wide), presumably in the cortical cytosol and/or the adjoining plasma membrane section, although the possibility cannot be excluded that some Al resided in the cell wall apposing this discrete region. However, as judged by the Al-morin assay, there were no detectable Al levels in the remaining, larger portion of the cell wall. The potential of the Al-morin method in Al toxicity studies is illustrated.
    Type of Medium: Electronic Resource
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