11 research outputs found
Bomb-pulse 14C analysis combined with 13C and 15N measurements in blood serum from residents of Malmö, Sweden
14C bomb-pulse dating and stable isotope analysis for growth rate and dietary information in breast cancer?
The purpose of this study was to perform an initial investigation of the possibility to determine breast cancer growth rate with 14C bomb-pulse dating. Tissues from 11 breast cancers, diagnosed in 1983, were retrieved from a regional biobank. The estimated average age of the majority of the samples overlapped the year of collection (1983) within 3Ï. Thus, this first study of tumour tissue has not yet demonstrated that 14C bomb-pulse dating can obtain information on the growth of breast cancer. However, with further refinement, involving extraction of cell types and components, there is a possibility that fundamental knowledge of tumour biology might still be gained by the bomb-pulse technique. Additionally, ÎŽ13C and ÎŽ15N analyses were performed to obtain dietary and metabolic information, and to serve as a base for improvement of the age determination
Exploring sources of biogenic secondary organic aerosol compounds using chemical analysis and the FLEXPART model
Molecular tracers in secondary organic aerosols (SOAs) can provide information on origin of SOA, as well as regional scale processes involved in their formation. In this study 9 carboxylic acids, 11 organosulfates (OSs) and 2 nitrooxy organosulfates (NOSs) were determined in daily aerosol particle filter samples from Vavihill measurement station in southern Sweden during June and July 2012. Several of the observed compounds are photo-oxidation products from biogenic volatile organic compounds (BVOCs). Highest average mass concentrations were observed for carboxylic acids derived from fatty acids and monoterpenes (12. 3 ± 15. 6 and 13. 8 ± 11. 6 ng mg-3, respectively). The FLEXPART model was used to link nine specific surface types to single measured compounds. It was found that the surface category sea and ocean was dominating the air mass exposure (56 %) but contributed to low mass concentration of observed chemical compounds. A principal component (PC) analysis identified four components, where the one with highest explanatory power (49 %) displayed clear impact of coniferous forest on measured mass concentration of a majority of the compounds. The three remaining PCs were more difficult to interpret, although azelaic, suberic, and pimelic acid were closely related to each other but not to any clear surface category. Hence, future studies should aim to deduce the biogenic sources and surface category of these compounds. This study bridges micro-level chemical speciation to air mass surface exposure at the macro level
Primary and secondary biomass burning aerosols determined by proton nuclear magnetic resonance (<sup>1</sup>H-NMR) spectroscopy during the 2008 EUCAARI campaign in the Po Valley (Italy)
Atmospheric organic aerosols are
generally classified as primary and secondary (POA and SOA) according to
their formation processes. An actual separation, however, is challenging when
the timescales of emission and gas-to-particle formation overlap. The
presence of SOA formation in biomass burning plumes leads to scientific
questions about whether the oxidized fraction of biomass burning aerosol is
rather of secondary or primary origin, as some studies would suggest, and
about the chemical compositions of oxidized biomass burning POA and SOA. In
this study, we apply nuclear magnetic resonance (NMR) spectroscopy to
investigate the functional group composition of fresh and aged biomass
burning aerosols during an intensive field campaign in the Po Valley, Italy.
The campaign was part of the EUCAARI project and was held at the rural
station of San Pietro Capofiume in spring 2008. Factor analysis applied to
the set of NMR spectra was used to apportion the wood burning contribution
and other organic carbon (OC) source contributions, including aliphatic
amines. Our NMR results, referred to the polar, water-soluble fraction of OC,
show that fresh wood burning particles are composed of polyols and aromatic
compounds, with a sharp resemblance to wood burning POA produced in wood
stoves, while aged samples are clearly depleted of alcohols and are enriched
in aliphatic acids with a smaller contribution of aromatic compounds. The
comparison with biomass burning organic aerosols (BBOA) determined by
high-resolution aerosol mass spectrometry (HR-TOF-AMS) at the site shows only
a partial overlap between NMR BB-POA and AMS BBOA, which can be explained by
either the inability of BBOA to capture all BB-POA composition, especially
the alcohol fraction, or the fact that BBOA account for insoluble organic
compounds unmeasured by the NMR. Therefore, an unambiguous composition for
biomass burning POA could not be derived from this study, with NMR analysis
indicating a higher O / C ratio compared to that measured for AMS BBOA. The
comparison between the two techniques substantially improves when adding
factors tracing possible contributions from biomass burning SOA, showing that
the operational definitions of biomass burning organic aerosols are more
consistent between techniques when including more factors tracing chemical
classes over a range of oxidation levels. Overall, the non-fossil total
carbon fraction was 50â57%, depending on the assumptions about the
<sup>14</sup>C content of non-fossil carbon, and the fraction of organic carbon
estimated to be oxidized organic aerosol (OOA) from HR-TOF-AMS measurements
was 73â100% modern