The DNA damage response to radiological imaging: from ROS and γH2AX foci induction to gene expression responses in vivo.

Candidate ionising radiation exposure biomarkers must be validated in humans exposed in vivo. Blood from patients undergoing positron emission tomography-computed tomography scan (PET-CT) and skeletal scintigraphy (scintigraphy) was drawn before (0 h) and after (2 h) the procedure for correlation analyses of the response of selected biomarkers with radiation dose and other available patient information. FDXR, CDKN1A, BBC3, GADD45A, XPC, and MDM2 expression was determined by qRT-PCR, DNA damage (γH2AX) by flow cytometry, and reactive oxygen species (ROS) levels by flow cytometry using the 2', 7'-dichlorofluorescein diacetate test in peripheral blood mononuclear cells (PBMC).

Small is beautiful: low activity alpha and gamma sources for small-scale radiation protection research experiments.

Purpose: Uncertainties regarding the magnitude of health effects following exposure to low doses of ionizing radiation remain a matter of concern both for professionals and for the public. There is consensus within the international radiation research community that more research is required on biological effects of radiation doses below 100 mGy applied at low dose rates. Moreover, there is a demand for increasing education and training of future radiation researchers and regulators.

Seasonal disconnect between streamflow and retention shapes riverine nitrogen export in the Willamette River Basin, Oregon.

Watershed nutrient balance studies traditionally focus on annual fluxes. In areas with strongly seasonal, Mediterranean-type climate regimes, riverine nutrient export may be greater during wet seasons when hydrologic forcing overwhelms or bypasses retention mechanisms. By combining data on riverine export with spatially detailed nutrient inputs, we examine how nitrogen (N) supply, retention, and streamflow shape annual and seasonal riverine N export in Oregon's Willamette River Basin (WRB).

A Nitrogen Physical Input-Output Model for Illinois.

Nitrogen (N) presents an important challenge for sustainability. Human intervention in the global nitrogen cycle has been pivotal in in providing goods and services to society. However, release of N beyond its intended societal use has many negative health and environmental consequences.

Linking dissolved and particulate phosphorus export in rivers draining California's Central Valley with anthropogenic sources at the regional scale.

Pollution of water resources by phosphorus (P) is a critical issue in regions with agricultural and urban development. In this study, we estimated P inputs from agricultural and urban sources in 24 catchments draining to the Central Valley in California and compared them with measured river P export to investigate hydrologic and anthropogenic factors affecting regional P retention and export. Using spatially explicit information on fertilizer use, livestock population, agricultural production, and human population, we calculated that net surface balances for anthropogenic P ranged from -12 to 648 kg P km yr in the early 2000s.

Nitrous oxide emission from denitrification in stream and river networks.

Nitrous oxide (N(2)O) is a potent greenhouse gas that contributes to climate change and stratospheric ozone destruction. Anthropogenic nitrogen (N) loading to river networks is a potentially important source of N(2)O via microbial denitrification that converts N to N(2)O and dinitrogen (N(2)). The fraction of denitrified N that escapes as N(2)O rather than N(2) (i.

Stream denitrification across biomes and its response to anthropogenic nitrate loading.

Anthropogenic addition of bioavailable nitrogen to the biosphere is increasing and terrestrial ecosystems are becoming increasingly nitrogen-saturated, causing more bioavailable nitrogen to enter groundwater and surface waters. Large-scale nitrogen budgets show that an average of about 20-25 per cent of the nitrogen added to the biosphere is exported from rivers to the ocean or inland basins, indicating that substantial sinks for nitrogen must exist in the landscape. Streams and rivers may themselves be important sinks for bioavailable nitrogen owing to their hydrological connections with terrestrial systems, high rates of biological activity, and streambed sediment environments that favour microbial denitrification.