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7 - Nitrogen processes in aquatic ecosystems
- from Part II - Nitrogen processing in the biosphere
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- By Patrick Durand, INRA, France, Lutz Breuer, Institute for Landscape Ecology and Resources Management, Penny J. Johnes, University of Reading, Gilles Billen, University Pierre & Marie Curie, Andrea Butturini, University of Barcelona, Gilles Pinay, University of Birmingham, Hans van Grinsven, Netherlands Environmental Assessment Agency, Josette Garnier, UMR Sisyphe UPMC ' CNRS, Michael Rivett, University of Birmingham, David S. Reay, University of Edinburgh, Chris Curtis, University College London Environmental Change Research Centre, Jan Siemens, University of Bonn Institute of Crop Science and Resource Conservation – Soil Sciences, Stephen Maberly, Centre for Ecology and Hydrology, Øyvind Kaste, Norwegian Institute for Water Research, Christoph Humborg, Stockholm University, Roos Loeb, B-ware Research Centre, Jeroen de Klein, Wageningen University and Research Centre, Josef Hejzlar, Institute of Hydrobiology, Nikos Skoulikidis, Pirkko Kortelainen, Finnish Environment Institute, Ahti Lepistö, Finnish Environment Institute, Richard Wright, Norwegian Institute for Water Research
- Edited by Mark A. Sutton, NERC Centre for Ecology and Hydrology, UK, Clare M. Howard, NERC Centre for Ecology and Hydrology, UK, Jan Willem Erisman, Gilles Billen, Albert Bleeker, Peringe Grennfelt, Hans van Grinsven, Bruna Grizzetti
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- Book:
- The European Nitrogen Assessment
- Published online:
- 16 May 2011
- Print publication:
- 14 April 2011, pp 126-146
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Summary
Executive summary
Nature of the problem
Freshwater ecosystems play a key role in the European nitrogen (N) cycle, both as a reactive agent that transfers, stores and processes N loadings from the atmosphere and terrestrial ecosystems, and as a natural environment severely impacted by the increase of these loadings.
Approaches
This chapter is a review of major processes and factors controlling N transport and transformations for running waters, standing waters, groundwaters and riparian wetlands.
Key findings/state of knowledge
The major factor controlling N processes in freshwater ecosystems is the residence time of water, which varies widely both in space and in time, and which is sensitive to changes in climate, land use and management.
The effects of increased N loadings to European freshwaters include acidification in semi-natural environments, and eutrophication in more disturbed ecosystems, with associated loss of biodiversity in both cases.
An important part of the nitrogen transferred by surface waters is in the form of organic N, as dissolved organic N (DON) and particulate organic N (PON). This part is dominant in semi-natural catchments throughout Europe and remains a significant component of the total N load even in nitrate enriched rivers.
In eutrophicated standing freshwaters N can be a factor limiting or co-limiting biological production, and control of both N and phosphorus (P) loading is often needed in impacted areas, if ecological quality is to be restored.
Development of a Lab-on-a-Chip for the Characterization of Human Cells
- Peter Ertl, Lukas Richter, Andy Mak, Christoph Stepper, Michael Kast, Hubert Brückl
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- Journal:
- MRS Online Proceedings Library Archive / Volume 1004 / 2007
- Published online by Cambridge University Press:
- 01 February 2011, 1004-P05-05
- Print publication:
- 2007
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Microfabricated biochips are developed to continuously monitor cellular phenotype dynamics in a non-invasive manner. In the presented work we describe the novel combination of contact-less micro-dielectric sensors and microfluidics for quantitative cell analysis. The cell chip consists of a polymeric fluidic (PDMS) system bonded to a glass wafer containing the electrodes while temperature and fluid flow are controlled by external heating and pumping stations. Additionally, the cell chip contains an integrated reference arm providing a low-noise detection environment by eliminating background signals and interferences. The high-density interdigitated capacitors (µIDC) are designed to monitor living cells in a space of approximately 10 nL volume by controlling critical electrode characteristics, such as size, shape and passivation composition as well as thickness. The integrated µIDCs are isolated by a 300 nm multi-passivation layer of defined dielectric property and provide non-invasive, stable, robust and non-drifting measurement conditions. The performance of this detector is evaluated using various bacterial, yeast and mammalian cells.
5 - Vaccine delivery and immunosuppression in cervical cancer
- Edited by Peter L. Stern, Paterson Institute for Cancer Research, Manchester, Peter C. L. Beverley, University College London, Miles Carroll, Oxford BioMedica (UK) Ltd
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- Book:
- Cancer Vaccines and Immunotherapy
- Published online:
- 06 January 2010
- Print publication:
- 17 August 2000, pp 82-106
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Summary
Introduction
A correlation between human papillomavirus (HPV) infection of cervical epithelial cells and cervical cancer has been unequivocally established. A significant proportion of early-stage precancerous lesions, cervical intraepithelial neoplasia (CIN) and essentially all cervical carcinomas are positive for certain high-risk types of HPV. The potential for immunotherapeutic intervention directed against viral targets expressed in cervical neoplasia is discussed in this chapter.
Human papillomaviruses and cervical neoplasia
Epidemiology
Human papillomaviruses (HPVs) are the most common sexually transmitted viruses and there are over 90 different HPV types described so far, of which about 35 types infect the anogenital tract. The risk of infection is approximately the same for men as for women, but in general the infection rate for HPV is greater at a younger age (below 25 years) than later in life. Most HPV infections are subclinical and go unnoticed, although some infections may progress into benign lesions, like the common genital warts in the anogenital region. HPV genomic DNA is detected in approximately 10–15% of the sexually active adults in the United States, whereas approximately only 1% of the population show clinical manifestations of infection, cervical intraepithelial neoplasia CIN. Only a minority of these CIN lesions will later progress into cervical carcinomas and adenocarcinomas.
Analysis of biopsy material of CIN lesions and cervical carcinomas showed the prevalence of HPV 6 or HPV 11 in low-grade CIN lesions, whereas HPV 16 and HPV 18 dominated in high-grade CIN and cervical carcinoma samples.