Read by QxMD icon Read

Isotopes in Environmental and Health Studies

Wolfram Meier-Augenstein, Arndt Schimmelmann
Many scientific publications about stable isotope ratios suffer from flawed practices regarding calibration and normalisation of raw δ values in conjunction with prescribed δ values of reference materials. Violations of the identical treatment principle with regards to samples and standards (i.e. reference materials) and lack of adherence to SI-mandated and IUPAC-recommended nomenclature exacerbate the widespread problem of lackadaisical analytical practice and reporting. Science is supposed to strive for exactness, whereas ambiguity and jargon confound interdisciplinary communication...
November 8, 2018: Isotopes in Environmental and Health Studies
Najeba F Salih
This study entails the measurement of the specific activity of natural radionuclides (226 Ra, 40 K and 232 Th) in 18 tooth samples obtained from the clinic of the Universiti Sains Malaysia (USM), Penang, by using an HPGe detector. The specific activity of 226 Ra, 40 K and 232 Th was measured to estimate the hazard index of the radionuclides, radium equivalent activities (Raeq ), external, internal hazard indices (Hex , Hin ), and absorbed dose (Dout , Din ). The maximum values of concentration of 226 Ra, 232 Th and 40 K in the tooth samples were found to be 60...
September 21, 2018: Isotopes in Environmental and Health Studies
Helge Bornhak, Klaus Jung, Peter Junghans, Peter Krumbiegel, Rolf Reinhard, Rolf Russow, Eckart Winkler
No abstract text is available yet for this article.
December 2018: Isotopes in Environmental and Health Studies
Philip J H Dunn, James F Carter
No abstract text is available yet for this article.
December 2018: Isotopes in Environmental and Health Studies
Juan Aguilera, Leah D Whigham
Particulate matter (PM) from atmospheric aerosols contains carbons that are harmful for living organisms and the environment. PM can originate from vehicle emissions, wearing of vehicle components, and dust. Size and composition determine PM transport and penetration depth into the respiratory system. Understanding PM emission characteristics is essential for developing strategies to improve air quality. The number of studies on carbon isotope composition (13 C/12 C) of PM samples to characterise emission factors has increased...
December 2018: Isotopes in Environmental and Health Studies
Peter Junghans, Solvig Görs, Martina Langhammer, Cornelia C Metges
We explored a novel doubly labelled water (DLW) method based on breath water (BW-DLW) in mice to determine whole body CO2 production and energy expenditure noninvasively. The BW-DLW method was compared to the DLW based on blood plasma. Mice (n = 11, 43.5 ± 4.6 g body mass (BM)) were administered orally a single bolus of doubly labelled water (1.2 g H2 18 O kg BM-1 and 0.4 g 2 H2 O kg BM-1 , 99 atom% (AP) 18 O or 2 H). To sample breath water, the mice were placed into a respiration vessel. The exhaled water vapour was condensed in a cold-trap...
December 2018: Isotopes in Environmental and Health Studies
Eduardo Cejudo, Sherry L Schiff
This paper examines the nitrogen isotope fractionation factors (α) associated with the volatilisation of ammonia from water under controlled conditions at two pH values (8.5 and 9.2). This experiment assumed the continuous removal of ammonia at a single purge rate of 10 mL air min-1 . The fractionation resulting from the removal of total ammonia from the water into an acid trap was named the observed isotope fractionation factor (αobs ), and it was measured as 1.019 (±0.0025) at pH 8.5 and 1.030 (±0.0025) at pH 9...
December 2018: Isotopes in Environmental and Health Studies
Hannu Nykänen, Promise A Mpamah, Antti J Rissanen
We studied natural and forestry-drained peatlands to examine the effect of over 34 years lowered water table on the δ13 C values of vegetation, bulk peat and subsoil. In the seven studied sites, δ13 C in the basal peat layer was 1.1 and 1.2 ‰ lower than that of the middle-layer and surface layer, respectively. Furthermore, there was a positive correlation between the δ13 C values of the basal and surface peat layers, possibly due to carbon (C) recycling within the peat column. In the same mire complex, natural fen peat δ13 C values were lower than those of the nearby bog, possibly due to the dominance of vascular plants on fen and the generally larger share of recycled C in the fens than in the bogs...
December 2018: Isotopes in Environmental and Health Studies
Mika Hayashi, Maximo Larry Lopez Caceres, Yoshihiro Nobori, Byambasuren Mijidsuren, Jens Boy
In the last decades a drastic increase in air temperature but a stable precipitation regime in Mongolia has led to gradual drying conditions. Thus, we evaluated the effect of spatial and climatic characteristics on the soil-plant nitrogen dynamics in three representative larch stands (Larix sibirica) with different geographical and climatic conditions using stable nitrogen isotopes. The results showed significant differences in the soil inorganic N content among sites and consequently a different isotopic composition in the plant-soil system...
December 2018: Isotopes in Environmental and Health Studies
Heike Wanke, Marcel Gaj, Matthias Beyer, Paul Koeniger, Josefina T Hamutoko
The study area is the Namibian part of the Cuvelai-Etosha Basin (CEB), located in central northern Namibia. The CEB is home to 40 % of Namibia's population, and most of the people live in rural areas. These people depend on both surface and groundwater resources which are limited in this dryland (mean annual rainfall ranging from 250 to 550 mm/a). The isotopic signatures of δ18 O and δ2 H from water samples (n = 61) collected over a course of 9 years from various research projects and existing (but mainly unpublished) data of meteoric water of the CEB (10 sites) were evaluated and local meteoric water lines (LMWLs) developed...
December 2018: Isotopes in Environmental and Health Studies
Gerhard Strauch
No abstract text is available yet for this article.
October 2018: Isotopes in Environmental and Health Studies
Andrius Garbaras, Justina Šapolaitė, Inga Garbarienė, Žilvinas Ežerinskis, Agnė Mašalaitė-Nalivaikė, Raminta Skipitytė, Artūras Plukis, Vidmantas Remeikis
In the present study, a combination of the stable carbon isotope ratio (13 C/12 C) with radiocarbon data (14 C) allowed us to perform the aerosol source apportionment. Filter samples of PM1 were collected during the warm and cold periods in rural and urban sites in Lithuania. The 14 C/12 C ratio of total carbon (TC) was measured using the single stage accelerator mass spectrometer quantifying of fossil and non-fossil derived aerosol emissions. The δ13 C value was measured using an elemental analyser interfaced with an isotope ratio mass spectrometer...
October 2018: Isotopes in Environmental and Health Studies
Carmen Grisel Méndez-García, Elizabeth Teresita Romero-Guzmán, Héctor Hernández-Mendoza, Corina Solís Rosales, Efraín Rafael Chávez Lomelí
The monitoring and evaluation of radioactive content in samples of PM10 aerosols have been investigated. The specific radioactivity concentrations (SRC) of 234 U, 235 U, 238 U and 232 Th were determined using inductively coupled plasma-sector field mass spectrometry in 13 samples collected in Mexico City and 8 samples collected in Cuernavaca in the centre of Mexico. The SRC of the radioisotopes analysed in PM10 were larger than those reported in PM2.5 . The enrichment factor was greater than 5, indicating anthropogenic influences in both sites...
October 2018: Isotopes in Environmental and Health Studies
Małgorzata Pająk, Marianna Kańska
To investigate isotope effects in the hydroxylation of [3',5'-2 H2 ]-α-methyl- and [3',5'-2 H2 ]-N-methyl-l-tyrosine, they were synthesised using acid catalysed isotope exchange at high temperature. The kinetic and solvent deuterium isotope effects on Vmax and Vmax /Km parameters of tyrosinase in its action on methylated derivatives of l-tyrosine were determined using the non-competitive spectrophotometric method. Lineweaver-Burk plots were used to consider the inhibition type of O-methyl-l-tyrosine, revealing that it is an uncompetitive inhibitor of tyrosinase...
October 2018: Isotopes in Environmental and Health Studies
Maximo Larry Lopez Caceres, Sayako Nakano, Juan Pedro Ferrio, Mika Hayashi, Takeshi Nakatsuka, Masaki Sano, Toshiro Yamanaka, Yoshihiro Nobori
The March 2011 Mega-Tsunami in eastern Japan damaged at different degrees the black pine (Pinus thunbergii) forests along the coast. In order to evaluate the recovery of black pine four years later, tree-ring samples from 9 trees for the period 2002-2014 were analyzed for ring growth and stable isotopes (δ13 C, δ15 N and δ18 O). The results showed that annual tree-ring width decreased approximately 70 % from the year 2011 to 2014 compared to the period previous to the tsunami (2002-2010). The multiple isotopic analyses showed that the reduction in growth was caused by soil salinity that prompted stomatal closure and an abrupt increase of tree-ring δ13 C...
October 2018: Isotopes in Environmental and Health Studies
Libin Wu, Liqiang Xu, Shengjie Hou, Xueying Wang, Pingqing Fu, Xiaodong Liu
We analyzed 13 C characteristics in samples of bird bones, feathers, eggshell carbonate and membrane from modern specimens of red-footed booby (Sula sula) as well as fish muscle, scales, and bones from its predominant food source, flying fish (Exocoetus volitans), and muscle from its secondary food source squid (Loligo chinensis), as well as in ancient sub-fossil samples of seabird and flying fish at the Xisha Islands, South China Sea. δ13 C is tissue-specific in both seabirds and flying fish due to the variance in turn-over among the tissues and differences in the type and content of amino acids across a diverse range of tissues...
October 2018: Isotopes in Environmental and Health Studies
Wael M Badawy, Octavian G Duliu, Marina V Frontasyeva, Hussein El Samman, Arnaud Faanhof
The activity concentrations of natural 40 K, 232 Th, and 238 U in 89 soil and 84 sediment samples collected over the entire Egyptian Nile River basin including the Nile delta are reported based on the results of epithermal neutron activation analysis. The average activity concentrations of 40 K, 232 Th, and 238 U equal to 15.3 ± 6.6, 15.6 ± 11.1 and 220 ± 31 Bq/kg, respectively, are significantly lower than those reported for the Upper Continental Crust, World Average Sediments as well as World Average Soils, suggesting the presence of a considerable portion of mafic material, most probably originating from the Ethiopian High Plateau...
October 2018: Isotopes in Environmental and Health Studies
Habu Tela Abba, Wan Muhamad Saridan Wan Hassan, Muneer Aziz Saleh, Abubakar Sadiq Aliyu, Ahmad Termizi Ramli, Hassan Abdulsalam
The Jos Plateau has been reported to have elevated levels of natural background radiation. A few earlier studies have measured the levels of natural radioactivity for specific locations in the area. Our interest is to investigate how geology of the study area influences the activity concentrations of natural radionuclides. Thus, the activity concentrations of terrestrial radionuclides in soil samples collected across the geological formations of the Jos Plateau were determined by gamma spectrometry technique...
October 2018: Isotopes in Environmental and Health Studies
Vasily A Vavilin, Sergey V Rytov, Lyudmila Y Lokshina
We described mathematically the process of peat methanization in a boreal mesotrophic fen. Gaseous and dissolved CH4 and CO2 as well as their δ13 C signatures were considered in the dynamic equations for incubation bottles. In accordance with the model, acetate, H2 , and CO2 were produced during cellulose hydrolysis and acidogenesis. 13 C/12 C in CO2 was a key variable reflecting dynamic changes in the rates of cellulose hydrolysis and acidogenesis, acetoclastic and hydrogenotrophic methanogenesis. As CO2 is the substrate in hydrogenotrophic methanogenesis, δ13 C-CO2 increased from the start till the dissolved hydrogen concentration became very low...
October 2018: Isotopes in Environmental and Health Studies
Biao Jin, Ivonne Nijenhuis, Massimo Rolle
We performed a model-based investigation to simultaneously predict the evolution of concentration, as well as stable carbon and bromine isotope fractionation during 1,2-dibromoethane (EDB, ethylene dibromide) transformation in a closed system. The modelling approach considers bond-cleavage mechanisms during different reactions and allows evaluating dual carbon-bromine isotopic signals for chemical and biotic reactions, including aerobic and anaerobic biological transformation, dibromoelimination by Zn(0) and alkaline hydrolysis...
August 2018: Isotopes in Environmental and Health Studies
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"