Nitrogen isotopic composition as a gauge of tumor cell anabolism-to-catabolism ratio.

Studies have suggested that cancerous tissue has a lower N/N ratio than benign tissue. However, human data have been inconclusive, possibly due to constraints on experimental design. Here, we used high-sensitivity nitrogen isotope methods to assess the N/N ratio of human breast, lung, and kidney cancer tissue at unprecedented spatial resolution.

Passive Sampling Tool for Actinides in Spent Nuclear Fuel Pools.

Spent nuclear fuel must be carefully managed to prevent pollution of the environment with radionuclides. Within the framework of correct radioactive waste management, spent fuel rods are stored in cooling pools to allow short-lived fission products to decay. If fuel rods leak, they liberate radionuclides into the cooling water; therefore, it is essential to determine radionuclide concentrations in the pool water for monitoring purposes and to plan the decommissioning process.

Solid-phase extraction of Ac using ion-imprinted resin and Am as a radioactive tracer for internal dosimetry and incorporation measurements.

Actinium-225 is a highly radiotoxic alpha-emitting radionuclide, which is currently in the spotlight owing to its promising radiotherapeutic applications in nuclear medicine. Personnel involved in the production and handling of actinium-225 is exposed to a risk of accidental incorporation of this radionuclide. Radiological protection regulations require regular monitoring of incorporation and internal dosimetry assessment for workers manipulating open radioactive sources.

An investigation of aspects of radiochemical purity of Tc-labelled human serum albumin nanocolloid.

Background: Nanocolloidal human serum albumin radiolabelled with Tc provides a diagnostic radiopharmaceutical for sentinel node lymphoscintigraphy. NanoHSA (Nanotop), a commercially available kit, enables the simple preparation of this radiopharmaceutical via reconstitution with pertechnetate eluted from a generator. Thin-layer chromatography is widely used for determining radiochemical purity in clinical nuclear medicine.

Uranium stability in a large wetland soil core probed by electron acceptors, carbonate amendments and wet-dry cycling in a long-term lysimeter experiment.

Understanding the hydro-biogeochemical conditions that impact the mobility of uranium (U) in natural or artificial wetlands is essential for the management of contaminated environments. Field-based research indicates that high organic matter content and saturation of the soil from the water table create favorable conditions for U accumulation. Despite the installation of artificial wetlands for U remediation, the processes that can release U from wetland soils to underlying aquifers are poorly understood.

Radionuclides in the Environment in Switzerland: A Retrospective Study of Transfer from Soil to the Human Body.

Natural radionuclides are ubiquitous in the environment. In addition, artificial radionuclides are present in the Swiss environment after the fallout of the nuclear bomb tests of the 1950s and 1960s, after the accident of the Chernobyl nuclear power plant, or after authorized discharges from the Swiss nuclear power plants and research centres. These radionuclides can create a radiological hazard to the environment and humans because of the increased risk of cancer due to the ionizing radiation they produce.

Origin and stability of uranium accumulation-layers in an Alpine histosol.

Uranium (U) accumulation in organic soils is a common phenomenon that can lead to high U concentration in montane wetlands. The stability of the immobilized U in natural wetlands following redox fluctuations and re-oxidation events, however, is not currently known. In this study, we investigated a saturated histosol that had accumulated up to 6000 ppm of U at 30 cm below ground level (bgl).

Determination of Ra at low levels in environmental, urine, and human bone samples and Ra in bone biopsy using alpha-spectrometry and metrological traceability to Th/Ra or Ra.

Ra is a natural radioelement emitting α and γ radiations. It can be highly concentrated in TENORM materials from the petroleum or fertilizer industries. In Switzerland, Ra is currently a radioactive inheritance problem from the watch industry.

A new two-strip TLC method for the quality control of technetium-99m mercaptoacetyl-triglycine (Tc-MAG3).

Background: Tc-mercaptoacetyl-triglycine (Tc-MAG3) has been used for dynamic renal imaging since about 30 years. Free pertechnetate (TcO), colloidal Tc ((TcO)), Tc-tartrate (precursor), precomplexes (Tc-(MAG3)) and lipophilic Tc-MAG2 are the main radiochemical impurities that may occur in the preparation. The total amount of these impurities has to be identified before release of the product for patient administration to guarantee patient safety and good image quality.

Impact of glacial/interglacial sea level change on the ocean nitrogen cycle.

The continental shelves are the most biologically dynamic regions of the ocean, and they are extensive worldwide, especially in the western North Pacific. Their area has varied dramatically over the glacial/interglacial cycles of the last million years, but the effects of this variation on ocean biological and chemical processes remain poorly understood. Conversion of nitrate to N by denitrification in sediments accounts for half or more of the removal of biologically available nitrogen ("fixed N") from the ocean.

(210)Po poisoning as possible cause of death: forensic investigations and toxicological analysis of the remains of Yasser Arafat.

The late president of the Palestinian Authority, Yasser Arafat, died in November 2004 in Percy Hospital, one month after having experienced a sudden onset of symptoms that included severe nausea, vomiting, diarrhoea and abdominal pain and which were followed by multiple organ failure. In spite of numerous investigations performed in France, the pathophysiological mechanisms at the origin of the symptoms could not be identified. In 2011, we found abnormal levels of polonium-210 ((210)Po) in some of Arafat's belongings that were worn during his final hospital stay and which were stained with biological fluids.

Iron fertilization of the Subantarctic ocean during the last ice age.

John H. Martin, who discovered widespread iron limitation of ocean productivity, proposed that dust-borne iron fertilization of Southern Ocean phytoplankton caused the ice age reduction in atmospheric carbon dioxide (CO2). In a sediment core from the Subantarctic Atlantic, we measured foraminifera-bound nitrogen isotopes to reconstruct ice age nitrate consumption, burial fluxes of iron, and proxies for productivity.

Changes in North Atlantic nitrogen fixation controlled by ocean circulation.

In the ocean, the chemical forms of nitrogen that are readily available for biological use (known collectively as 'fixed' nitrogen) fuel the global phytoplankton productivity that exports carbon to the deep ocean. Accordingly, variation in the oceanic fixed nitrogen reservoir has been proposed as a cause of glacial-interglacial changes in atmospheric carbon dioxide concentration. Marine nitrogen fixation, which produces most of the ocean's fixed nitrogen, is thought to be affected by multiple factors, including ocean temperature and the availability of iron and phosphorus.