Search results for "ISOTOPE"

IAEA Contribution to Nanosized Targeted Radiopharmaceuticals for Drug Delivery.

2022

The rapidly growing interest in the application of nanoscience in the future design of radiopharmaceuticals and the development of nanosized radiopharmaceuticals in the late 2000′s, resulted in the creation of a Coordinated Research Project (CRP) by the International Atomic Energy Agency (IAEA) in 2014. This CRP entitled ‘Nanosized delivery systems for radiopharmaceuticals’ involved a team of expert scientist from various member states. This team of scientists worked on a number of cutting-edge areas of nanoscience with a focus on developing well-defined, highly effective and site-specific delivery systems of radiopharmaceuticals. Specifically, focus areas of various teams of scientists com…

Chemical and isotopic characterization of rainwater in volcanic, urban and industrial areas of Sicily (Italy)

2021

The chemical composition of rainwater depends on (i) the dissolution of gases and particulate matter emitted by different sources, (ii) the chemical and physical reactions occurring during local and regional scale transport, and (iii) removal processes. The source of major and trace elements dissolved in rainwater can be both natural (e.g. sea salts, volcanic emissions, geogenic dust, biogenic material) and anthropogenic (e.g. industrial plants, vehicular traffic, domestic heating, vessel traffic). A group of trace elements has been recently brought to attention, especially for their possible environmental impacts, the Technology-critical elements (TCEs): Ga, Ge, In, Te, Nb, Ta, Tl, the Pla…

Growth and population structure of perch in relation to diet in a small humic lake, Valkea-Kotinen

2011

Lake Valkea-Kotinen is a long-term ecological monitoring site in the Evo region of southern Finland .The aim of this study was to investigate the growth and population structure of perch (Perca fluviatilis L.) in relation to diet in Valkea-Kotinen in order to provide reference data for a study investigating effects of increased loading of dissolved organic matter to nearby Lake Alinen Mustajärvi. Valkea-Kotinen was predominantly inhabited by small benthivorous perch. The growth relationship between opercular bone and total length of perch in the lake is similar to those earlier analysed for nearby lakes. Compared to wider growth rates, the growth of perch was slow and similar to those in si…

Lake size and fish diversity determine resource use and trophic position of a top predator in high-latitude lakes

2015

Prey preference of top predators and energy flow across habitat boundaries are of fundamental importance for structure and function of aquatic and terrestrial ecosystems, as they may have strong effects on production, species diversity, and food-web stability. In lakes, littoral and pelagic food-web compartments are typically coupled and controlled by generalist fish top predators. However, the extent and determinants of such coupling remains a topical area of ecological research and is largely unknown in oligotrophic high-latitude lakes. We analyzed food-web structure and resource use by a generalist top predator, the Arctic charr Salvelinus alpinus (L.), in 17 oligotrophic subarctic lakes…

The variable position of Arctic charr (Salvelinus alpinus (L.)) in subarctic lake food webs

2013

Strontium Uptake and Intra-Population 87Sr/86Sr Variability of Bones and Teeth—Controlled Feeding Experiments With Rodents (Rattus norvegicus, Cavia …

2020

Strontium isotopes in biogenic apatite, especially enamel, are widely employed to determine provenance and track migration in palaeontology and archaeology. Body tissues record the 87Sr/86Sr of bioavailable Sr of ingested food and water. To identify non-local individuals, knowledge of the 87Sr/86Sr of a non-migratory population is required. However, varying factors such as tissue turnover rates, feeding selectivity, Sr content, digestibility of food, and the ingestion of mineral dust can influence body tissue 87Sr/86Sr. To evaluate the Sr contribution of diet and water to mammalian hard tissues 87Sr/86Sr, controlled feeding studies are necessary. Here we present 87Sr/86Sr from controlled fe…

Trophic ecology of piscivorous Arctic charr (Salvelinus alpinus (L.)) in subarctic lakes with contrasting food-web structures

2019

The trophic ecology of piscivorous Arctic charr (Salvelinus alpinus (L.); charr) in the food webs of large subarctic lakes is not well understood. We assessed charr diets, parasites, growth, maturity, and stable isotope ratios in Fennoscandian subarctic lakes dominated by monomorphic or polymorphic whitefish (Coregonus lavaretus (L.)) populations. Charr density was low in all lakes, except in profundal habitats. Charr shifted to piscivory at small size (16–25 cm total length) and consumed a range of prey-fish sizes (2–25 cm). Cannibalism was observed in a few individuals from one monomorphic whitefish lake. Charr matured at 37–51 cm (5–8 years old), grew to 52–74 cm maximum observed length …

Testing a spatially distributed sediment delivery model (SEDD) in a forested basin by cesium-137 technique

2005

The aim of the paper is to validate the sediment delivery distributed (SEDD) model for estimating hillslope sediment yield estimates using net soil erosion values obtained by the cesium-137 technique. The cesium-137 technique provides spatially-distributed measurements useful to verify the predictive capability of a distributed sediment yield model. The application of the cesium-137 technique requires a calibration procedure to convert measurements of 137Cs inventories to estimates of net soil erosion rates. Rainfall and sediment yield data from 1978 to 1994 in a small Calabrian basin forested with eucalyptus trees, were initially used to calibrate, at mean annual temporal scale, the SEDD m…

In-gas laser ionization and spectroscopy of actinium isotopes near the N=126 closed shell

2017

The in-gas laser ionization and spectroscopy (IGLIS) techniquewas applied on the $^{212–215}$Ac isotopes, produced at the Leuven Isotope Separator On-Line (LISOL) facility by using the in-gas-cell and the in-gas-jet methods. The first application under on-line conditions of the in-gas-jet laser spectroscopy method showed a superior performance in terms of selectivity, spectral resolution, and efficiency in comparison with the in-gas-cell method. Following the analysis of both experiments, the magnetic-dipole moments for the $^{212–215}$Ac isotopes, electric-quadrupole moments and nuclear spins for the $^{214,215}$Ac isotopes are presented and discussed. A good agreement is obtained with lar…

Charge radius changes of even-even neutron-rich Tellurium isotopes

2005

Laser spectroscopy based on resonant ionization of laser-desorbed atoms has been used to study the neutron-rich tellurium isotopes with the COMPLIS facility at ISOLDE-CERN. The isotope shift and the hyperfine structure of several neutron-rich Te isotopes: $^{120–136}$Te and $^{123m–133m}$Te have been measured. From the hyperfine structure and the isotope shift we can extract the magnetic and quadrupole moments and the change in the mean square charge radius respectively. The mean square charge radii of the even-even isotopes have been deduced and their comparison with the known data for the other elements near Z=50 is presented. The experimental $\delta$ is compared with that obtained from …