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Risk of cancer after low doses of ionising radiation: retrospective cohort study in 15 countries
Cardis, E,Vrijheid, M,Blettner, M,Gilbert, E,Hakama, M,Hill, C,Howe, G,Kaldor, J,Muirhead, C R,Schubauer-Berigan, M,Yoshimura, T,Bermann, F,Cowper, G,Fix, J,Hacker, C,Heinmiller, B,Marshall, M,Thierry BMJ 2005 BMJ Vol.331 No.7508
<P>To provide direct estimates of risk of cancer after protracted low doses of ionising radiation and to strengthen the scientific basis of radiation protection standards for environmental, occupational, and medical diagnostic exposures.</P>
Sea spray aerosol as a unique source of ice nucleating particles
DeMott, Paul J.,Hill, Thomas C. J.,McCluskey, Christina S.,Prather, Kimberly A.,Collins, Douglas B.,Sullivan, Ryan C.,Ruppel, Matthew J.,Mason, Ryan H.,Irish, Victoria E.,Lee, Taehyoung,Hwang, Chung Y National Academy of Sciences 2016 Proceedings of the National Academy of Sciences Vol.113 No.21
<P>Ice nucleating particles (INPs) are vital for ice initiation in, and precipitation from, mixed-phase clouds. A source of INPs from oceans within sea spray aerosol (SSA) emissions has been suggested in previous studies but remained unconfirmed. Here, we show that INPs are emitted using real wave breaking in a laboratory flume to produce SSA. The number concentrations of INPs from laboratory-generated SSA, when normalized to typical total aerosol number concentrations in the marine boundary layer, agree well with measurements from diverse regions over the oceans. Data in the present study are also in accord with previously published INP measurements made over remote ocean regions. INP number concentrations active within liquid water droplets increase exponentially in number with a decrease in temperature below 0 degrees C, averaging an order of magnitude increase per 5 degrees C interval. The plausibility of a strong increase in SSA INP emissions in association with phytoplankton blooms is also shown in laboratory simulations. Nevertheless, INP number concentrations, or active site densities approximated using 'dry' geometric SSA surface areas, are a few orders of magnitude lower than corresponding concentrations or site densities in the surface boundary layer over continental regions. These findings have important implications for cloud radiative forcing and precipitation within low-level and midlevel marine clouds unaffected by continental INP sources, such as may occur over the Southern Ocean.</P>
Insect Response to Climate Change: What are We Testing for?
Jung M.-P.,Andrew N.R.,Hill S.J.,Binns M.,Ridley E.V.,Bahar M.H.,Khusro M.,Yates M.,Fyfe C. 한국응용곤충학회 2012 한국응용곤충학회 학술대회논문집 Vol.2012 No.10
Understanding how researchers are tackling globally important issues, such as climate change, is crucial to identify whether current research is comprehensive enough to make substantive predictions about general responses to climate change. We assessed the type of studies being conducted by researchers to understand the impacts of climate change on insects, published. Most published research is generated from Europe and North America and being dedicated to core data analysis, with reviews being highly produced. Temperature – only is the main climate change factor being analysed, with most researchers are assessing changes in abundance or distribution/range shifts. Of most concern is the number of studies which do not specifically identify a climate change factor (ie just arm wave), the lack of studies on Hemimetabolous insects and the need for more studies to assess specific mechanistic responses to climate change.
Methyl Donor Status Influences DNMT Expression and Global DNA Methylation in Cervical Cancer Cells
Poomipark, Natwadee,Flatley, Janet E,Hill, Marilyn H,Mangnall, Barbara,Azar, Elnaz,Grabowski, Peter,Powers, Hilary J Asian Pacific Journal of Cancer Prevention 2016 Asian Pacific journal of cancer prevention Vol.17 No.7
Background: Methyl donor status influences DNA stability and DNA methylation although little is known about effects on DNA methyltransferases. The aim of this study was to determine whether methyl-donor status influences DNA methyltransferase (Dnmt) gene expression in cervical cancer cells, and if so, whether there are associated effects on global DNA methylation. Materials and Methods: The human cervical cancer cell line, C4-II, was grown in complete medium and medium depleted of folate (F-M+) and folate and methionine (F-M-). Growth rate, intracellular folate, intracellular methionine and homocysteine in the extracellular medium were measured to validate the cancer cell model of methyl donor depletion. Dnmt expression was measured by qRT-PCR using relative quantification and global DNA methylation was measured using a flow cytometric method. Results: Intracellular folate and methionine concentrations were significantly reduced after growth in depleted media. Growth rate was also reduced in response to methyl donor depletion. Extracellular homocysteine was raised compared with controls, indicating disturbance to the methyl cycle. Combined folate and methionine depletion led to a significant down-regulation of Dnmt3a and Dnmt3b; this was associated with an 18% reduction in global DNA methylation compared with controls. Effects of folate and methionine depletion on Dnmt3a and 3b expression were reversed by transferring depleted cells to complete medium. Conclusions: Methyl donor status can evidently influence expression of Dnmts in cervical cancer cells, which is associated with DNA global hypomethylation. Effects on Dnmt expression are reversible, suggesting reversible modulating effects of dietary methyl donor intake on gene expression, which may be relevant for cancer progression.
Woo, W.,An, G.B.,Kingston, E.J.,DeWald, A.T.,Smith, D.J.,Hill, M.R. Elsevier Science 2013 ACTA MATERIALIA Vol.61 No.10
Spatial variations of residual stresses were determined through the thickness of 70mm thick ferritic steel welds created using low (1.7kJmm<SUP>-1</SUP>) and high (56kJmm<SUP>-1</SUP>) heat inputs. Two-dimensional maps of the longitudinal residual stress were obtained by using the contour method. The results were compared to neutron diffraction measurements through the thickness at different locations from the weld centerline. The deep hole drilling technique was utilized to confirm the maximum stress locations and magnitudes. The results show that significant tensile stresses (~90% of yield strength) occur along the weld centerline near the top surface (within 10% of the depth) in the low heat-input specimen. Meanwhile, in the high heat-input weld, the peak stress moved towards the heat-affected zone at a depth of ~40% of the thickness. Finally, the influence of residual stresses on potential fracture behavior of the welded joints is discussed.
Gorby, Y. A.,Yanina, S.,McLean, J. S.,Rosso, K. M.,Moyles, D.,Dohnalkova, A.,Beveridge, T. J.,Chang, I. S.,Kim, B. H.,Kim, K. S.,Culley, D. E.,Reed, S. B.,Romine, M. F.,Saffarini, D. A.,Hill, E. A.,Sh Proceedings of the National Academy of Sciences 2006 PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF Vol.103 No.30
<P>Shewanella oneidensis MR-1 produced electrically conductive pilus-like appendages called bacterial nanowires in direct response to electron-acceptor limitation. Mutants deficient in genes for c-type decaheme cytochromes MtrC and OmcA, and those that lacked a functional Type II secretion pathway displayed nanowires that were poorly conductive. These mutants were also deficient in their ability to reduce hydrous ferric oxide and in their ability to generate current in a microbial fuel cell. Nanowires produced by the oxygenic phototrophic cyanobacterium Synechocystis PCC6803 and the thermophilic, fermentative bacterium Pelotomaculum thermopropionicum reveal that electrically conductive appendages are not exclusive to dissimilatory metal-reducing bacteria and may, in fact, represent a common bacterial strategy for efficient electron transfer and energy distribution.</P>
Tuning microcavities in thermally rearranged polymer membranes for CO<sub>2</sub> capture
Han, S. H.,Kwon, H. J.,Kim, K. Y.,Seong, J. G.,Park, C. H.,Kim, S.,Doherty, C. M.,Thornton, A. W.,Hill, A. J.,Lozano, Á,. E.,Berchtold, K. A.,Lee, Y. M. The Royal Society of Chemistry 2012 Physical Chemistry Chemical Physics Vol.14 No.13
<P>Microporous materials have a great importance in catalysis, delivery, storage and separation in terms of their performance and efficiency. Most microporous materials are comprised of inorganic frameworks, while thermally rearranged (TR) polymers are a microporous organic polymer which is tuned to optimize the cavity sizes and distribution for difficult separation applications. The sub-nano sized microcavities are controlled by <I>in situ</I> thermal treatment conditions which have been investigated by positron annihilation lifetime spectroscopy (PALS). The size and relative number of cavities increased from room temperature to 230 °C resulting in improvements in both permeabilities and selectivities for H<SUB>2</SUB>/CO<SUB>2</SUB> separation due to the significant increase of gas diffusion and decrease of CO<SUB>2</SUB> solubility. The highest performance of the well-tuned TR-polymer membrane was 206 Barrer for H<SUB>2</SUB> permeability and 6.2 of H<SUB>2</SUB>/CO<SUB>2</SUB> selectivity, exceeding the polymeric upper bound for gas separation membranes.</P> <P>Graphic Abstract</P><P>Thermally rearranged polybenzoxazoles with tuned cavities for hydrogen purification and carbon dioxide separation even at high temperature were developed to apply for a syn gas separation. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c2cp23729f'> </P>