350 research outputs found

    Regulation of Vascular Endothelial Growth Factor in endometrial cancer cells by food compounds

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    Endometrial cancer is one of the most significant gynaecological malignancies that affect women from New Zealand and the rest of the world. One of the critical stages in the development of a tumour is the onset of hypoxia. The malignancy responds by having raised levels of Hypoxia Inducible Factor (HIF) that in turn induces increased production of Vascular Endothelial Growth Factor (VEGF). VEGF is a potent angiogenic factor that will mediate vascular supply of nutrients and oxygen to the developing tumour. The aim of this study was to investigate whether two compounds found in extracts of plant materials, Resveratrol (Resveratrol) and Epigallocatechin gallate (EGCG), altered the levels of VEGF in the supernatant of cultured endometrial cancer cells. Resveratrol is a phytoalexin that is found in many foods, such as grapes, nuts and berries, as well as in high concentrations in some red wines. 100 ”M of resveratrol was added to cell cultures for 24 hours. VEGF levels in the supernatant were then analysed using ELISA. Resveratrol was found to have significant inhibitory effects in both primary endometrial cancer cell cultures and immortalised endometrial cancer cell cultures. Resveratrol was also shown to reverse the increase in VEGF caused by the hypoxia mimic cobalt chloride (CoCl₂). Epigallocatechin gallate (EGCG) is an antioxidant catechin extracted from green tea. The effect of EGCG was analysed using the same method as for resveratrol. 100 ”M of EGCG was also shown to have a significant inhibitory effect on the level of VEGF in the supernatant of cultured endometrial cancer cells, as well as reducing the effect of CoCl₂. These results suggest that selected food compounds, resveratrol and EGCG, can reduce VEGF levels by inhibiting HIF. Further investigation This may have anti-tumour effects in women with endometrial cancer

    Large-area submillimeter resolution CdZnTe strip detector for astronomy

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    We report the first performance measurements of a sub-millimeter CdZnTe strip detector developed as a prototype for space-borne astronomical instruments. Strip detector arrays can be used to provide two-dimensional position resolution with fewer electronic channels than pixellated arrays. Arrays of this type and other candidate technologies are under investigation for the position-sensitive backplane detector for a coded-aperture telescope operating in the range of 30 - 300 keV. The prototype is a 1.4 mm thick, 64 multiplied by 64 stripe CdZnTe array of 0.375 mm pitch in both dimensions, approximately one square inch of sensitive area. Pulse height spectra in both single and orthogonal stripe coincidence mode were recorded at several energies. The results are compared to slab- and pixel-geometry detector spectra. The room-temperature energy resolution is less than 10 keV (FWHM) for 122 keV photons with a peak-to-valley ratio greater than 5:1. The response to photons with energies up to 662 keV appears to be considerably improved relative to that of previously reported slab and pixel detectors. We also show that strip detectors can yield spatial and energy resolutions similar to those of pixellated arrays with the same dimensions. Electrostatic effects on the pulse heights, read-out circuit complexity, and issues related to design of space borne instruments are also discussed

    Innovations for Improving Courtroom Communications and Views from Appellate Courts

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    Symposium: Improving Communications In the Courtroo

    Development of an orthogonal-stripe CdZnTe gamma radiation imaging spectrometer

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    We report performance measurements of a sub-millimeter resolution CdZnTe strip detector developed as a prototype for astronomical instruments operating with good efficiency in the 30-300 keV photon energy range. The prototype is a 1.4 mm thick, 64×64 contact stripe CdZnTe array of 0.375 mm pitch in both dimensions. Pulse height spectra were recorded in orthogonal-stripe coincidence mode which demonstrate room-temperature energy resolution \u3c10 keV (FWHM) for 122 keV photons with a peak-to-valley ratio \u3e5:1. Good response is also demonstrated at higher energies using a coplanar grid readout configuration. Spatial resolution capabilities finer than the stripe pitch are demonstrated. We present the image of a 133Ba source viewed through a collimator slit produced by a 4×4 stripe detector segment. Charge signals from electron and hole collecting contacts are also discussed

    Supplementary information files for An iron ore-based catalyst for producing hydrogen and metallurgical carbon via catalytic methane pyrolysis for decarbonisation of the steel industry

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    Supplementary files for article An iron ore-based catalyst for producing hydrogen and metallurgical carbon via catalytic methane pyrolysis for decarbonisation of the steel industry Experiments to investigate the catalytic pyrolysis of methane using an iron ore-based catalyst were carried out to optimize catalytic activity and examine the purity of the carbon produced from the process for the first time. Ball milling of the iron ore at 300 rpm for varying times – from 30 to 330 minutes – was studied to determine the effect of milling time on methane conversion. Optimal milling for 270 minutes led to a five-fold increase in methane conversion from ca. 1% to 5%. Further grinding resulted in a decline of methane conversion to 4% shown by SEM to correspond to an increase in particle size caused by agglomeration. Data from Raman and Mössbauer spectroscopy and H2 temperature programmed reduction indicated a change in phase from magnetite to maghemite and hematite (at the particle surface) as the grinding time increased. Analysis of the carbon produced as a byproduct of the reaction indicated a highly pure material with the potential to be used as an additive for steel production. </p

    Teachers' classroom feedback: still trying to get it right

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    This article examines feedback traditionally given by teachers in schools. Such feedback tends to focus on children's acquisition and retrieval of externally prescribed knowledge which is then assessed against mandated tests. It suggests that, from a sociocultural learning perspective, feedback directed towards such objectives may limit children's social development. In this article, I draw on observation and interview data gathered from a group of 27 9- to 10-year olds in a UK primary school. These data illustrate the children's perceived need to conform to, rather than negotiate, the teacher's feedback comments. They highlight the children's sense that the teacher's feedback relates to school learning but not to their own interests. The article also includes alternative examples of feedback which draw on children's own inquiries and which relate to the social contexts within which, and for whom, they act. It concludes by suggesting that instead of looking for the right answer to the question of what makes teachers' feedback effective in our current classrooms, a more productive question might be how a negotiation can be opened up among teachers and learners themselves, about how teachers' feedback could support children's learning most appropriately

    Identifying the impact of collective action on US federal nuclear energy policy between 1975 and 1990

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    Our research aims to quantify the impact of protest size on the probability of legislative change. We do this via a formal two-period model and testing derived hypotheses using a lagged time series model in the context of the US Nuclear Regulatory Committee
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