- A. Brodkorb (1)
- R. Chiaraluce (1)
- V. Consalvi (1)
- O. Doka (1)
- R. Florio (1)
- G. Gianese (1)
- M. Goyrik (1)
- F.A. Hoekstra (1)
- A. Koudijs (1)
- A. Kroes-Nijboer (1)
- M.C. Krol (1)
- T.T. Leeuwen van (1)
- J.F.T. Lieshout van (1)
- E. Magner (1)
- D. Oboroceanu (1)
- J. Oost van der (1)
- W. Peters (1)
- P. Venema (1)
- L. Wang (1)
- G.R. Werf van der (1)
- W.F. Wolkers (1)
Dynamic biomass burning emission factors and their impact on atmospheric CO mixing ratios.
Leeuwen, T.T. van; Peters, W. ; Krol, M.C. ; Werf, G.R. van der - \ 2013
Journal of Geophysical Research: Atmospheres 118 (2013)12. - ISSN 2169-897X - p. 6797 - 6815.
transform infrared-spectroscopy - trace gas emissions - zoom model tm5 - carbon-monoxide - southern africa - fire emissions - burned-area - interannual variability - laboratory measurements - smoldering combustion
 Biomass burning is a major source of trace gases and aerosols, influencing atmospheric chemistry and climate. To quantitatively assess its impact, an accurate representation of fire emissions is crucial for the atmospheric modeling community. So far, most studies rely on static emission factors (EF) which convert estimates of dry matter burned to trace gas and aerosol emissions. These EFs are often based on the arithmetic mean of field measurements stratified by biome, neglecting the variability in time and space. Here we present global carbon monoxide (CO) emission estimates from fires based on six EF scenarios with different spatial and temporal variability, using dry matter emission estimates from the Global Fire Emissions Database (GFED). We used the TM5 model to transport these different bottom-up estimates in the atmosphere and found that including spatial and temporal variability in EFs impacted CO mixing ratios substantially. Most scenarios estimated higher CO mixing ratios (up to 40% more CO from fires during the burning season) over boreal regions compared to the GFED standard run, while a decrease (~15%) was estimated over the continent of Africa. A comparison to atmospheric CO observations showed differences of 10–20¿ppb between the scenarios and systematic deviations from local observations. Although temporal correlations of specific EF scenarios improved for certain regions, an overall “best” set of EFs could not be selected. Our results provide a new set of emission estimates that can be used for sensitivity analyses and highlight the importance of better understanding spatial and temporal variability in EFs for atmospheric studies in general and specifically when using CO or aerosols concentration measurements to top-down constrain fire carbon emissions.
The effect of high pressure microfluidization on the structure and length distribution of whey protein fibrils
Oboroceanu, D. ; Wang, L. ; Kroes-Nijboer, A. ; Brodkorb, A. ; Venema, P. ; Magner, E. ; Auty, M.A. - \ 2011
International Dairy Journal 21 (2011)10. - ISSN 0958-6946 - p. 823 - 830.
transform infrared-spectroscopy - atomic-force microscopy - beta-lactoglobulin gels - amyloid fibrils - milk-proteins - heat - aggregation - rheology - flow
The effect of high pressure microfluidization on native ß-lactoglobulin (ß-lg) or whey protein isolate (WPI), both before and after heat-induced protein fibril formation at pH 2.0, was investigated using atomic force microscopy (AFM), shear birefringence, reversed phase high pressure liquid chromatography, attenuated total reflectance-Fourier transform infrared spectroscopy and fluorescence spectroscopy. The morphology and length distribution of the fibrils were determined using AFM and flow-induced birefringence, respectively. High pressure (= 50 MPa) microfluidization treatment of ß-lg induced ˜30% protein denaturation, accompanied by changes in secondary structure. Fibrils formed from high pressure treated ß-lg or WPI were similar in length to fibrils formed from non-pressure treated proteins. High pressure (= 50 MPa) microfluidization of fibrils formed from ß-lg or WPI resulted in their breakup into more uniformly sized and much shorter fibrils. Microfluidization pressures of up to 170 MPa resulted in slightly shorter fibrils but did not completely dissociate them.
Determination of free fatty acids in cooking oil: traditional spectrophotometry and optothermal window assay
Goyrik, M. ; Ajtony, Z. ; Doka, O. ; Alebic-Juretic, A. ; Bicanic, D.D. ; Koudijs, A. - \ 2006
Instrumentation Science and Technology 34 (2006)1-2. - ISSN 1073-9149 - p. 119 - 128.
transform infrared-spectroscopy - olive oil - lipase - extraction
The concept of optothermal window (OW) (with 632.8 nm He-Ne laser used as a radiation source), combined with copper soap based colorimetry, was proposed as a new analytical tool to determine total free fatty acid (FFA) content in thermally treated cooking oil. The results obtained were compared to those acquired by conventional spectroscopy; the correlation between the two methods is high for FFA concentrations exceeding 2 µmol/mL
Calcium-induced tertiary structure modifications of endo-B-1,3-glucanase form Pyrococcus furiosus in 7.9 M guanidinium chloride
Chiaraluce, R. ; Gianese, G. ; Angelaccio, S. ; Florio, R. ; Lieshout, J.F.T. van; Oost, J. van der; Consalvi, V. - \ 2005
Biochemical Journal 386 (2005)3. - ISSN 0264-6021 - p. 515 - 524.
transform infrared-spectroscopy - protein secondary structure - 3-dimensional structures - ftir spectroscopy - free-energy - recognition - database - endo-beta-1,3-glucanase - intermediate - alignments
The family 16 endo-b-1,3 glucanase from the extremophilic archaeon Pyrococcus furiosus is a laminarinase, which in 7.9 M GdmCl (guanidinium chloride) maintains a significant amount of tertiary structure without any change of secondary structure. The addition of calcium to the enzyme in 7.9 M GdmCl causes significant changes to the near-UV CD and fluorescence spectra, suggesting a notable increase in the tertiary structure which leads to a state comparable, but not identical, to the native state. The capability to interact with calcium in 7.9 M GdmCl with a consistent recovery of native tertiary structure is a unique property of this extremely stable endo-b-1,3 glucanase. The effect of calcium on the thermodynamic parameters relative to the GdmCl-induced equilibrium unfolding has been analysed by CD and fluorescence spectroscopy. The interaction of calcium with the native form of the enzyme is studied by Fourier-transform infrared spectroscopy in the absorption region of carboxylate groups and by titration in the presence of a chromophoric chelator. A homology-based model of the enzyme is generated and used to predict the putative binding site(s) for calcium and the structural interactions potentially responsible for the unusual stability of this protein, in comparison with other family 16 glycoside hydrolases
In situ FTIR assessment of desiccation-tolerant tissues
Wolkers, W.F. ; Hoekstra, F.A. - \ 2003
Spectroscopy: an international journal 17 (2003). - ISSN 0712-4813 - p. 297 - 313.
transform infrared-spectroscopy - protein secondary structure - electron-paramagnetic-resonance - typha-latifolia l - plant craterostigma-plantagineum - carrot somatic embryos - abscisic-acid - arabidopsis-thaliana - phase-transitions - seed development
This essay shows how Fourier transform infrared (FTIR) microspectroscopy can be applied to study thermodynamic parameters and conformation of endogenous biomolecules in desiccation-tolerant biological tissues. Desiccation tolerance is the remarkable ability of some organisms to survive complete dehydration. Seed and pollen of higher plants are well known examples of desiccation-tolerant tissues. FTIR studies on the overall protein secondary structure indicate that during the acquisition of desiccation tolerance, plant embryos exhibit proportional increases in alpha-helical structures and that beta-sheet structures dominate upon drying of desiccation sensitive-embryos. During ageing of pollen and seeds, the overall protein secondary structure remains stable, whereas drastic changes in the thermotropic response of membranes occur, which coincide with a complete loss of viability. Properties of the cytoplasmic glassy matrix in desiccation-tolerant plant organs can be studied by monitoring the position of the OH-stretching vibration band of endogenous carbohydrates and proteins as a function of temperature. By applying these FTIR techniques to maturation-defective mutant seeds of Arabidopsis thaliana we were able to establish a correlation between macromolecular stability and desiccation tolerance. Taken together, in situ FTIR studies can give unique information on conformation and stability of endogenous biomolecules in desiccation-tolerant tissues.