The hygroscopicity and reactivity of fatty acid atmospheric aerosol proxies are affected by nanostructure 

2021 ◽  
Author(s):  
Adam Milsom ◽  
Adam Squires ◽  
Nicholas Terrill ◽  
Andrew Ward ◽  
Christian Pfrang
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Atmospheric Aerosol ◽  
Structural Changes ◽  
Chemical Reactivity ◽  
Structural Parameters ◽  
Raman Microscopy ◽  
X Ray ◽  
Molecular Arrangement ◽  
Surfactant Material

<p>Atmospheric aerosol hygroscopicity and reactivity play a significant role in determining aerosol fate, and are affected by composition and other physical properties. Organic aerosol emissions contain fatty acids, along with sugars such as fructose. As surfactants, fatty acids organise into a range of nanostructures (3-D molecular arrangements), dependent on water content and mixture composition. In this study, we were able to demonstrate (and quantify) that the chemical reactivity of this proxy is dependent on its 3-D molecular arrangement. Furthermore, we have determined the effect of each observed nanostructure on hygroscopicity by measuring the swelling of these nanostructures as a function of relative humidity. We did this by coating capillaries with a fatty acid/sugar as a mixture for an urban aerosol, and following structural changes with simultaneous Small-Angle X-ray Scattering (SAXS) and Raman microscopy, at a synchrotron X-ray source. SAXS measured the nano-structural parameters required to follow both the reaction kinetics (ozonolysis) and hygroscopic swelling of each nanostructure. Raman microscopy provided complementary kinetic information and supported these findings. We found that the molecular arrangement of surfactant material has an impact on both the chemical kinetics and hygroscopicity. This has implications for the persistence of particulate matter in the urban environment and surfactant material in the atmosphere.</p>

IV.—An X-ray Examination of Saturated Dicarboxylic Acids and Amides of the Fatty Acid Series

1929 ◽  
Vol 48 ◽  
pp. 20-27 ◽  
Author(s):  
Edward Henderson
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Malonic Acid ◽  
Dicarboxylic Acids ◽  
X Rays ◽  
X Ray ◽  
Fatty Acid Amides

SummarySeveral additional members of the series of normal saturated dicarboxylic acids have been investigated by X-rays, and the results are in agreement with the conclusions arrived at in an earlier paper. In the series of mono- and di-alkyl malonic acids, successive reflection planes are separated by the length of one molecule. The series of fatty acid amides closely resembles that of the fatty acids themselves. The cleavage planes are separated by the length of two molecules oriented in opposite directions.My thanks are due to Mr N. K. Adam for the specimens of mono- and dioctadecyl malonic acid, and to Sir James Walker for his advice and helpful criticism.

scholarly journals Probing conformational changes of human serum albumin due to unsaturated fatty acid binding by chemical cross-linking and mass spectrometry

2005 ◽  
Vol 387 (3) ◽  
pp. 695-702 ◽  
Author(s):  
Bill X. HUANG ◽  
Chhabil DASS ◽  
Hee-Yong KIM
Keyword(s):  
Mass Spectrometry ◽  
Fatty Acids ◽  
Fatty Acid ◽  
Human Serum Albumin ◽  
Serum Albumin ◽  
Human Serum ◽  
Conformational Changes ◽  
Cross Linking ◽  
X Ray ◽  
Chemical Cross Linking

Mass spectrometry with chemical cross-linking was used to probe the conformational changes of HSA (human serum albumin) in solution on interaction with monounsaturated OA (oleic acid) or polyunsaturated AA (arachidonic acid) or DHA (docosahexaenoic acid). Fatty acid-free or -bound HSA was modified with lysine-specific cross-linkers and digested with trypsin. Cross-linked peptides were analysed by nano-electrospray ionization MS to localize the sites of cross-linking. Our data indicated that a local conformational change involving movement of the side chains of Lys-402 of subdomain IIIA or Lys-541 of subdomain IIIB occurred upon binding of all three fatty acids. Our data also indicated that the side chains of Lys-205 (IIA) and Lys-466 (IIIA) moved closer towards each other upon binding AA or DHA, but not OA, suggesting that the conformations of HSA when bound to mono- and poly-unsaturated fatty acids are distinctively different. While these observations agreed with previous X-ray crystallographic studies, the distances between ε-amino groups of most cross-linked lysine pairs were shorter than the crystal structure predicted, possibly reflecting a discrepancy between the solution and crystal structures. This method can serve as a useful complement to X-ray crystallography, particularly in probing the structure of a protein in solution.

Combined scanning X-ray diffraction and holographic imaging of cardiomyocytes

2017 ◽  
Vol 50 (2) ◽  
pp. 612-620 ◽  
Author(s):  
Jan-David Nicolas ◽  
Marten Bernhardt ◽  
Martin Krenkel ◽  
Claudia Richter ◽  
Stefan Luther ◽  
...  
Keyword(s):  
Electron Density ◽  
Structural Changes ◽  
Structural Parameters ◽  
Scattering Data ◽  
Cardiac Muscle Cells ◽  
Saxs Data ◽  
Full Field ◽  
X Ray ◽  
Holographic Imaging ◽  
Freeze Dried

This article presents scanning small-angle X-ray scattering (SAXS) experiments on the actomyosin assemblies in freeze-dried neo-natal rat cardiac muscle cells. By scanning the cells through a sub-micrometre focused beam, the local structure and filament orientation can be probed and quantified. To this end, SAXS data were recorded and analyzed directly in reciprocal space to generate maps of different structural parameters (scanning SAXS). The scanning SAXS experiments were complemented by full-field holographic imaging of the projected electron density, following a slight rearrangement of the instrumental setup. It is shown that X-ray holography is ideally suited to complete missing scattering data at low momentum transfer in the structure factor, extending the covered range of spatial frequencies by two orders of magnitude. Regions of interest for scanning can be easily selected on the basis of the electron density maps. Finally, the combination of scanning SAXS and holography allows for a direct verification of possible radiation-induced structural changes in the cell.

Transesterification of Kapok Seed Oil (Ceiba pentandra) Using Heterogeneous Catalyst Bimetallic Oxide of Zinc and Copper Supported by γ-Alumina

2020 ◽  
Vol 988 ◽  
pp. 87-94
Author(s):  
Nyoman Puspa Asri ◽  
W.D. Prasetiyo ◽  
A. Kafidhu ◽  
A. Atiqoh ◽  
E.A. Puspitasari ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Zinc Oxide ◽  
Fatty Acid ◽  
Seed Oil ◽  
Acid Methyl Ester ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ceiba Pentandra ◽  
Activity Test ◽  
Acid Methyl

Biodiesel was produced from Kapok seed (Ceiba pentandra) oil (KSO) using heterogeneous bimetallic oxide of copper and zinc supported by γ-alumina. The Alumina-supported copper oxide-zinc oxide (CuO-ZnO γ /- Al2O3) further notated by ACZ was synthesized using precipitation, impregnation and gel methods. It also was characterized using the X-ray diffraction (X-RD), and Brunauwer-Emmett Teller (BET) methods. Before being transesterified, KSO was subjected to pretreatment with the aim of minimizing gum and other impurities and reducing the concentration of free fatty acids. The activity test of ACZ catalyst was done by introducing it through the transesterification process of KSO with methanol. The transesterification process was carried out in a laboratory scale three neck flask. The effect of calcinating temperature (°C), and calcinating time of catalyst (h) on the yield of fatty acid methyl ester (FAME) were studied, respectively. The results revealed that the kapok seed oil was worthy and potentially to transesterified into biodiesel using ACZ catalyst with highest FAME yield of 46.67%.

scholarly journals Domain Organization in Plant Blue-Light Receptor Phototropin2 of Arabidopsis thaliana Studied by Small-Angle X-ray Scattering

2020 ◽  
Vol 21 (18) ◽  
pp. 6638
Author(s):  
Masayoshi Nakasako ◽  
Mao Oide ◽  
Yuki Takayama ◽  
Tomotaka Oroguchi ◽  
Koji Okajima
Keyword(s):  
Blue Light ◽  
Small Angle ◽  
Structural Changes ◽  
Structural Parameters ◽  
Kinase Domain ◽  
Full Length ◽  
Receptor Protein ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

Phototropin2 (phot2) is a blue-light (BL) receptor protein that regulates the BL-dependent activities of plants for efficient photosynthesis. Phot2 is composed of two light-oxygen-voltage sensing domains (LOV1 and LOV2) to absorb BL, and a kinase domain. Photo-activated LOV domains, especially LOV2, play a major role in photo-dependent increase in the phosphorylation activity of the kinase domain. The atomic details of the overall structure of phot2 and the intramolecular mechanism to convert BL energy to a phosphorylation signal remain unknown. We performed structural studies on the LOV fragments LOV1, LOV2, LOV2-linker, and LOV2-kinase, and full-length phot2, using small-angle X-ray scattering (SAXS). The aim of the study was to understand structural changes under BL irradiation and discuss the molecular mechanism that enhance the phosphorylation activity under BL. SAXS is a suitable technique for visualizing molecular structures of proteins in solution at low resolution and is advantageous for monitoring their structural changes in the presence of external physical and/or chemical stimuli. Structural parameters and molecular models of the recombinant specimens were obtained from SAXS profiles in the dark, under BL irradiation, and after dark reversion. LOV1, LOV2, and LOV2-linker fragments displayed minimal structural changes. However, BL-induced rearrangements of functional domains were noted for LOV2-kinase and full-length phot2. Based on the molecular model together with the absorption measurements and biochemical assays, we discuss the intramolecular interactions and domain motions necessary for BL-enhanced phosphorylation activity of phot2.

scholarly journals Automated structural modeling in biological small-angle X-ray scattering

2014 ◽  
Vol 70 (a1) ◽  
pp. C404-C404
Author(s):  
Dmitry Svergun
Keyword(s):  
Data Processing ◽  
Small Angle ◽  
Large Scale ◽  
Structural Changes ◽  
Structural Parameters ◽  
Structural Models ◽  
Assessment Tools ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

Small-angle X-ray scattering (SAXS) experiences a renaissance in the studies of macromolecular solutions allowing one to study the structure of native particles and complexes and to rapidly analyze structural changes in response to variations in external conditions. New high brilliance sources and novel data analysis methods significantly enhanced resolution and reliability of structural models provided by the technique (Graewert & Svergun, 2013). Automation of the experiment, data processing and interpretation make solution SAXS a streamline tool for large scale structural studies in molecular biology. The recent developments will be presented including robotic sample changers, pipelines for data processing, computation of structural parameters and ab initio models, classification of the folding states of macromolecules. A prototype of an expert systems allowing for automated generation and assessment of structural models will be considered. A synergistic use of SAXS with the high resolution methods like crystallography and NMR, but also with complementary biophysical and biochemical techniques will be discussed. The problems of validation of SAXS-generated models, and the use of data quality assessment tools for the deposition of the models and experimental data will be discussed. Further perspectives of the hybrid applications of SAXS with other techniques in structural biology will be outlined.

Synchrotron Radiation X-Ray Scattering Techniques for Studying the Micro- and Nanostructure of Wood and their Relation to the Mechanical Properties

2008 ◽  
Vol 599 ◽  
pp. 107-125 ◽  
Author(s):  
Martin Müller
Keyword(s):  
Cell Wall ◽  
Synchrotron Radiation ◽  
Mechanical Stress ◽  
Structural Changes ◽  
Structural Parameters ◽  
Cellulose Microfibrils ◽  
X Rays ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

X-ray scattering techniques have been a very useful tool for the non-destructive analysis of the wood structure. X-rays are sensitive to structural parameters such as the composite structure of wood cell walls, the crystal structure of cellulose microfibrils and their helical arrangement in the cell wall, which is usually described by the microfibril angle (MFA). With the availability of synchrotron radiation sources novel experiments on wood have become possible. The increased flux of X-rays makes the in situ and time-resolved investigation of structural changes upon mechanical stress possible. The low-divergence synchrotron radiation X-rays can be focused down to sub-micrometer size, enabling scanning studies of the wood nanostructure with (sub-)microscopic position resolution. This chapter highlights very recent advances in the understanding of wood micro- and nanostructure, which were only possible using synchrotron radiation. Examples include the MFA determination in the individual layers of the secondary cell wall, the imaging of the helical structure of the cellulose microfibrils in the cell wall, lattice strain as induced by applied mechanical stress and the structural changes of different wood types under external tensile stress.

scholarly journals Plasma Fatty Acids and Quantitative Ultrasound, DXA and pQCT Derived Parameters in Postmenopausal Spanish Women

Nutrients ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 1454
Author(s):  
Raúl Roncero-Martín ◽  
Ignacio Aliaga ◽  
Jose M. Moran ◽  
Luis M. Puerto-Parejo ◽  
Purificación Rey-Sánchez ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Fatty Acids ◽  
Fatty Acid ◽  
Femoral Neck ◽  
Postmenopausal Women ◽  
Quantitative Ultrasound ◽  
Quantitative Computed Tomography ◽  
Peripheral Quantitative Computed Tomography ◽  
Dual Energy ◽  
X Ray

Different factors may contribute to the development of osteopenia or osteoporosis. Fatty acids are key nutrients for health, and a number of studies have reported an association between bone mineral density (BMD) and fatty acid intake. We aimed to investigate the relationships between serum levels of different fatty acids and bone parameters determined by quantitative bone ultrasound (QUS), peripheral quantitative computed tomography (pQCT), and dual-energy X-ray absorptiometry (DXA) in a sample of Spanish postmenopausal women. We enrolled a total of 301 postmenopausal women (median age 59 years; interquartile range (IQR) 7) in this study. All participants underwent full densitometric screening, including calcaneal quantitative ultrasound (QUS), peripheral quantitative computed tomography (pQCT), and dual-energy X-ray absorptiometry (DXA), as well as plasma fatty acid measurement. After adjustment for potential confounders, plasma n-3 polyunsaturated fatty acid (PUFA) levels correlated with BMD in the spine (r = 0.150; p = 0.014) and femoral neck (r = 0.143; p = 0.019). By multiple linear regression, an independent statistically significant positive relationship was observed between BMD in the spine and BMI (β = 0.288; p = 0.001) as well as total plasma n-3 PUFAs (β = 0.155; p = 0.009). The plasma n-3 PUFA level was also a significant and positive predictor of BMD at the femoral neck (β = 0.146; p = 0.009). Independent risk factors for low BMD (T-score ≤ 1) were determined by logistic regression analysis, and a relatively high level of plasma n-3 PUFAs (OR = 0.751; 95% CI 0.587-0.960, p = 0.022) was identified as a protective factor against low bone mass. In this single-center sample of Spanish postmenopausal women, we reported a significant positive and statistically independent association between BMD and plasma levels of n-3 PUFAs.

Compound formation in binary fatty-acid mixtures

1955 ◽  
Vol 233 (1193) ◽  
pp. 195-202 ◽  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
High Resolution ◽  
Compound Formation ◽  
X Ray ◽  
Fatty Acid Mixtures

Long crystal spacings d 1 and short spacings d 2 and d 3 of C 12 –C 14 , C 14 –C 16 and C 16 –C 18 fatty - acid mixtures have been determined using a high resolution X -ray diffractometer in an attempt to elucidate the question of compound formation in these mixtures. Both d 1 and d 3 spacings showed significant changes in relation to the composition of the mixtures whereas d 2 spacings remained practically unchanged. The changes in d 1 and d 3 spacings are interpreted as denoting limited intersolubility of the component fatty acids and partial compound formation. Numerical correlation found between the above changes seems to indicate a shortening of the distance between alternate carbon atoms of the higher melting component in mixtures containing 30 to 70 mol. percent of this component.

Sign in / Sign up

Export Citation Format

Share Document