44,758 research outputs found

    International differential pricing: easy in theory but hard in practice

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    <a href="http://dx.doi.org/10.7175/fe.v14i3.648">http://dx.doi.org/10.7175/fe.v14i3.648</a

    Assessment of diastolic dysfunction by tissue Doppler echocardiography in patients with heart failure

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    Proteomic characterization of the cytotoxic mechanism of gold (III) porphyrin 1a, a potential anticancer drug

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    There has been increasing interest in the potential applications of gold (III) complexes as anticancer drugs with higher cytotoxicity and fewer side effects than existing metal anticancer drugs. Our previous findings demonstrated that gold (III) porphyrin la preferentially induced apoptosis in a cancer cell line (SUNE1). In this study, we identified differentially expressed proteins related to the drug's cytotoxic action by comparing the protein alterations induced by gold (III) porphyrin la and cisplatin treatments. Several clusters of altered proteins were identified, including cellular structure and stress-related chaperone proteins, proteins involved in reactive oxygen species and enzyme proteins, translation factors, proteins that mediate cell proliferation or differentiation, and proteins participating in the internal degradation systems. Our results indicated that multiple factors leading to apoptosis were involved in drug cytotoxicity in SUNE1 cells. The balance between pro-apoptotic and anti-apoptotic signals determined the final fate of cancer cells. Ā© 2006 Wiley-VCH Verlag GmbH & Co. KGaA.postprin

    Estimation of paleo-firing temperatures using luminescence signals for the volcanic lava baked layer in Datong, China

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    Eight paleo-fired samples from the baked layer in different depths under the lava and one unfired sample were collected from Datong, China. Fine quartz grains (4ā€“11 Ī¼m) from samples were used for probing into relationship between luminescence signals and paleo-firing temperatures. Findings from the re-firing experiments indicated that using thermoluminescence (TL) and optically stimulated luminescence (OSL) sensitivity changes could estimate the paleo-firing temperatures of samples: (1) 110 Ā°C TL sensitivity change rate against the re-firing temperature can tell whether the sample has been fired to temperatures above 500 Ā°C or not; (2) 150 Ā°C TL sensitivity against the re-firing temperature can indicate whether the sample has been fired to temperatures above 900 Ā°C or not; (3) the more specific paleo-firing temperatures can be estimated by comparing the ratio of OSL and 150 Ā°C TL sensitivities against re-firing temperatures. Results showed that the paleo-firing temperatures of the eight lava-baked samples decreased exponentially with the distance from the lava. Based on the estimated temperature profile, the temperature of the lava was estimated to be about 1100 Ā°C.postprin

    Luminescence dating of volcanic eruptions in Datong, northern China

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    In this study, fine-grain quartz was used for luminescence dating for lava baked samples from different sites in Datong. Optical stimulated luminescence (OSL), thermal transferred OSL (TT-OSL)/recuperated OSL (Re-OSL) and thermoluminescence (TL) dating protocols were applied. For these samples, the OSL signals saturate at about 300ā€“400 Gy, which limits their age to less than 100 ka based on their ambient dose rates. The TT-OSL/Re-OSL method has poor dose recovery. TL dating gives reliable results, and multiple-aliquot regenerative-dose TL method with sensitivity change correction based on the 325 Ā°C TL peak of a test dose can be applied for samples up to 400 ka. The results indicate that the ages of the volcanoes in Datong are from 380 ka to 84 ka. The volcanic activity started earlier in the southeast area than those in the northwest part, which is consist with the literature data.postprin

    Interval mapping of quantitative trait loci with selective DNA pooling data

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    Selective DNA pooling is an efficient method to identify chromosomal regions that harbor quantitative trait loci (QTL) by comparing marker allele frequencies in pooled DNA from phenotypically extreme individuals. Currently used single marker analysis methods can detect linkage of markers to a QTL but do not provide separate estimates of QTL position and effect, nor do they utilize the joint information from multiple markers. In this study, two interval mapping methods for analysis of selective DNA pooling data were developed and evaluated. One was based on least squares regression (LS-pool) and the other on approximate maximum likelihood (ML-pool). Both methods simultaneously utilize information from multiple markers and multiple families and can be applied to different family structures (half-sib, F2 cross and backcross). The results from these two interval mapping methods were compared with results from single marker analysis by simulation. The results indicate that both LS-pool and ML-pool provided greater power to detect the QTL than single marker analysis. They also provide separate estimates of QTL location and effect. With large family sizes, both LS-pool and ML-pool provided similar power and estimates of QTL location and effect as selective genotyping. With small family sizes, however, the LS-pool method resulted in severely biased estimates of QTL location for distal QTL but this bias was reduced with the ML-pool

    Field-Effect Ferroelectric-Semiconductor Solar Cells

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    Traditional photovoltaic devices employ limited semiconductor materials largely due to the P-N junction structure. We have developed a new kind of field-effect ferroelectric semiconductor solar cells. Prototype cells have been demonstrated successfully. Substantial photovoltaic effect and rectifying behavior were experimentally observed. In addition, simulation study was conducted to indicate that the induced electric field due to the bound surface changes of the ferroelectric could be extended into the semiconductor. The simulation results are consistent with experimental observations. This unique device structure offers a promising alternative to achieve novel solar cells. The new cells are not P-N junction based, and in principle offer more flexibility in materials selection and optimizing charge generation, separation and collection for achieving high performance solar cells.published_or_final_versio
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