Radiation damage from EELS and NEXAFS in diesel soot and diesel soot extracts

Braun, Artur; Kubátová, Alena; Wirick, S.; Mun, Simon

doi:10.1016/j.elspec.2007.08.002

Cited by 71 publications

(48 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Determining the mass fraction of CO 3 2− with respect to total carbon is challenging without the availability of appropriate standards for the organic component. While it is possible for radiation damage to cause the appearance of C*O 3 in STXM chambers open to the air, 41 this was not observed during the course of these experiments; spectra for standard compounds showed no resolvable contribution from the C*O 3 transition. Furthermore, the STXM chamber used here was evacuated and backfilled with helium to avoid unwanted reaction of gases with particles in these studies.…”

Section: Resultsmentioning

confidence: 95%

Biological Impacts on Carbon Speciation and Morphology of Sea Spray Aerosol

Pham

O’Brien

Fraund

et al. 2017

ACS Earth Space Chem.

View full text Add to dashboard Cite

Sea spray aerosol (SSA) can have complex carbon speciation that is affected by biological conditions in the seawater from which it originates. Biologically derived molecules can also interact with other longer-lived organic and inorganic carbon species in the sea surface microlayer and in the process of bubble bursting. An isolated wave channel facility was used to generate sea spray aerosol during a 1 month mesocosm study. Two consecutive phytoplankton blooms occurred, and sea spray aerosol was sampled throughout. Scanning transmission X-ray microscopy coupled with near-edge X-ray absorption fine structure spectroscopy (STXM-NEXAFS) was used to determine spatially resolved carbon speciation within individual particles from 0.18 to 3.2 μm. During phytoplankton blooms, coarse-mode particles exhibited an increased abundance of carboxylic acid-rich needlelike structures. The extent of organic enrichment in fine-mode particles correlates with the occurrence of aliphatic-rich organic species, as detected by an intense C 1s → σ(C−H)* excitation. These aliphatic-rich species had a strong association with graphitic carbon, as detected by a C 1s → σ* exciton excitation. This enrichment was unique to particles collected in the aerodynamic size range 0.18−0.32 μm and corresponded with the decrease in hygroscopicity. Aliphatic organics can significantly suppress the particle hygroscopicity when they replace salt, thus influencing the effect of sea spray aerosol on light scattering and cloud formation. These results suggest that graphitic carbon is concentrated in the sea surface microlayer during phytoplankton blooms and released through wave action. These results may have implications for radiative transfer and carbon cycling in the ocean−atmosphere system.

show abstract

Section: Resultsmentioning

confidence: 95%

Biological Impacts on Carbon Speciation and Morphology of Sea Spray Aerosol

Pham

O’Brien

Fraund

et al. 2017

ACS Earth Space Chem.

View full text Add to dashboard Cite

show abstract

“…Peaks B and C observed in the calcite impurity (IMP) were assigned to 1s→π*states transitions of carboxyl and carbonyl groups, which are often connected with organic material in aragonite in XANES studies [67][68][69]. Previous EELS studies did not record peaks B and C in aragonite [64], while XANES studies show the presence of peaks B and C, and attributed their origin to the surface contamination or surface states [70].…”

Section: Carbon K-edgementioning

confidence: 97%

Probing carbonate in bone forming minerals on the nanometre scale

et al. 2015

View full text Add to dashboard Cite

To devise new strategies to treat bone disease in an ageing society, a more detailed characterisation of the process by which bone mineralises is needed. In vitro studies have suggested that carbonated mineral might be a precursor for deposition of bone apatite. Increased carbonate content in bone may also have significant implications in altering the mechanical properties, for example in diseased bone. However, information about the chemistry and coordination environment of bone mineral, and their spatial distribution within healthy and diseased tissues, is lacking. Spatially resolved analytical transmission electron microscopy is the only method available to probe this information at the length scale of the collagen fibrils in bone. In this study, scanning transmission electron microscopy combined with electron energy-loss spectroscopy (STEM-EELS) was used to differentiate between calcium-containing biominerals (hydroxyapatite, carbonated hydroxyapatite, beta-tricalcium phosphate and calcite). A carbon K-edge peak at 290 eV is a direct marker of the presence of carbonate. We found that the oxygen K-edge structure changed most significantly between minerals allowing discrimination between calcium phosphates and calcium carbonates. The presence of carbonate in carbonated HA (CHA) was confirmed by the formation of peak at 533 eV in the oxygen K-edge. These observations were confirmed by simulations using density functional theory. Finally, we show that this method can be utilised to map carbonate from the crystallites in bone. We propose that our calibration library of EELS spectra could be extended to provide spatially resolved information about the coordination environment within bioceramic implants to stimulate the development of structural biomaterials.

show abstract

“…The stark contrast with the protein crystallography community on the level of description of the issue is clear. Note also here that the portion of the soft X-ray XAS community concerned with the study of carbon, nitrogen and oxygen K-edges of biological compounds, polymers and (gas phase) hydrocarbons has paid more attention to beam damage effects, see for example [15,[77][78][79][80][81] and references therein.…”

Section: Introductionmentioning

confidence: 99%