Supplementary material to "An organic crystalline state in ageing atmospheric aerosol proxies: spatially resolved structural changes in levitated fatty acid particles"

2021 ◽  
Author(s):  
Adam Milsom ◽  
Adam M. Squires ◽  
Jacob A. Boswell ◽  
Nicholas J. Terrill ◽  
Andrew D. Ward ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Atmospheric Aerosol ◽  
Crystalline State ◽  
Structural Changes ◽  
Spatially Resolved ◽  
Supplementary Material

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>

Metastability in Monolayer Films Transferred onto Solid Substrates by the Langmuir-Blodgett Method: IR Evidence for Transfer-Induced Phase Transitions

1994 ◽  
Vol 48 (10) ◽  
pp. 1196-1203 ◽  
Author(s):  
Fazale R. Rana ◽  
Suci Widayati ◽  
Brian W. Gregory ◽  
Richard A. Dluhy
Keyword(s):  
Fatty Acid ◽  
Conformational Changes ◽  
Structural Changes ◽  
High Surface ◽  
Solid Substrate ◽  
Water Interface ◽  
Monolayer Films ◽  
Langmuir Blodgett ◽  
Monomolecular Film ◽  
Air Water Interface

The rate at which a monomolecular film is deposited onto a solid substrate in the Langmuir-Blodgett process of preparing supported monolayer films influences the final structure of the transferred film. Attenuated total reflectance infrared spectroscopic studies of monolayers transferred to germanium substrates show that the speed at which the substrate is drawn through the air/water interface influences the final conformation in the hydrocarbon chains of amphiphilic film molecules. This transfer-induced effect is especially evident when the monolayer is transferred from the expanded region of surface-pressure-molecular-area isotherms at low surface pressures; the effect is minimized when the film molecules are transferred from condensed phases at high surface pressures. This phenomenon has been observed for both a fatty acid and a phospholipid, which suggests that these conformational changes may occur in a variety of hydrocarbon amphiphiles transferred from the air/water interface. This conformational ordering may be due to a kinetically limited phase transition taking place in the meniscus formed between the solid substrate and aqueous subphase. In addition, the results obtained for both the phospholipid and fatty acid suggest that the structure of the amphiphile may help determine the extent and nature of the transfer-speed-induced structural changes taking place in the monomolecular film.

MECHANOCHEMICAL ACTIVATION METHOD TECHNOLOGICAL PROCESS REFINING OF VEGETABLE OILS

2020 ◽  
Author(s):  
В.И. МАРТОВЩУК ◽  
С.А. КАЛМАНОВИЧ ◽  
А.А. ЛОБАНОВ ◽  
Е.В. МАРТОВЩУК
Keyword(s):  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Acid Composition ◽  
Vegetable Oils ◽  
Structural Changes ◽  
Mechanochemical Activation ◽  
Cavitation Effect ◽  
Temperature Mode ◽  
The Stability ◽  
Local Pressures

Исследовано влияние механохимической активации на гидратируемость фосфолипидов растительных масел. Для эксперимента использовали механохимический активатор, обеспечивающий высокие локальные давления, сдвиговые деформации и кавитационный эффект, при следующих параметрах работы: давление на контактирующих поверхностях 70 МПа, частота 180 Гц, скорость сдвига 10200 с–1, размер капли эмульсии 1–2 мкм. Обработку образцов подсолнечного масла осуществляли в течение от 0 до 80 с при температурах 50, 60 и 70°С. Активность фосфолипидов оценивали по величине их адсорбции на границе с полярной поверхностью (водой) в оптимальном температурном режиме при обработке в механохимическом активаторе и без нее. Установлено, что механохимическая активация способствует снижению энергии активации с 6,4 до 4,7 кДж/моль за счет химических и структурных изменений фосфолипидов. В жирнокислотном составе фосфолипидов на 10–12% увеличилось содержание олеиновой кислоты при соответствующем уменьшении линолевой; в фосфатидилэтаноламинах и фосфатидилсеринах отмечено увеличение до 3% содержания пальмитиновой кислоты и незначительно – стеариновой кислоты. Эти изменения жирнокислотного состава и физических свойств фосфолипидов способствуют повышению их гидратируемости и уменьшению доли полиненасыщенных жирных кислот, что должно обеспечить стабильность обработанных в механохимическом активаторе масел к окислению при хранении. The effect of mechanochemical activation on the hydration of phospholipids of vegetable oils has been studied. A mechanochemical activator providing high local pressures, shear deformations and cavitation effect was used for the experiment with the following operating parameters: pressure on the contact surfaces of 70 MPa, frequency of 180 Hz, shear rate of 10200 s–1, the size of the emulsion drop of 1–2 microns. Processing of sunflower oil samples was carried out during 0 to 80 s at temperatures of 50, 60 and 70°C. The activity of phospholipids was estimated by the amount of their adsorption at the border with the polar surface (water) in the optimal temperature mode when processed in a mechanochemical activator and without it. It was found that mechanochemical activation contributes to a decrease in the activation energy from 6,4 to 4,7 kJ/mol due to chemical and structural changes in phospholipids. In the fatty acid composition of phospholipids, the content of oleic acid increased by 10–12% with a corresponding decrease in linoleic acid; in phosphatidylethanolamines and phosphatidylserines, the increase in the content of palmitic acid was noted to 3%, and stearic acid – slightly. These changes in the fatty acid composition and physical properties of phospholipids contribute to increasing their hydration and reducing the proportion of polyunsaturated fatty acids, which should ensure the stability of the oils processed in the mechanochemical activator to oxidation during storage.

scholarly journals An organic crystalline state in ageing atmospheric aerosol proxies: spatially resolved structural changes in levitated fatty acid particles

2021 ◽  
Author(s):  
Adam Milsom ◽  
Adam M. Squires ◽  
Jacob A. Boswell ◽  
Nicholas J. Terrill ◽  
Andrew D. Ward ◽  
...  
Keyword(s):  
Oleic Acid ◽  
Air Quality ◽  
Liquid Crystalline ◽  
Structural Changes ◽  
Unsaturated Fatty Acids ◽  
Organic Aerosols ◽  
Cloud Formation ◽  
Phase Gradient ◽  
Spatially Resolved ◽  
Surface Active

Abstract. Organic aerosols are key components of the Earth’s atmospheric system. The phase state of organic aerosols is known to be a significant factor in determining aerosol reactivity, water uptake and atmospheric lifetime – with wide implications for cloud formation, climate, air quality and human health. Unsaturated fatty acids contribute to urban cooking emissions and sea spray aerosols. These compounds, exemplified by oleic acid and its sodium salt, are surface active and have been shown to self-assemble into a variety of liquid-crystalline phases upon addition of water. Here we observe a crystalline acid–soap complex in acoustically levitated oleic acid–sodium oleate particles. We developed a synchrotron-based simultaneous Small-Angle & Wide-Angle X-ray Scattering (SAXS/WAXS)/Raman microscopy system to probe physical and chemical changes in the proxy during exposure to humidity and the atmospheric oxidant ozone. We present a spatially resolved structural picture of a levitated particle during humidification, revealing a phase gradient consisting of a disordered liquid crystalline shell and crystalline core. Ozonolysis is significantly slower in the crystalline phase compared with the liquid phase and a significant portion (34 ± 8 %) of unreacted material remains after extensive oxidation. We present experimental evidence of inert surface layer formation during ozonolysis, taking advantage of spatially resolved simultaneous SAXS/WAXS experiments. These observations suggest atmospheric lifetimes of surface-active organic species in aerosols are highly phase dependent, potentially impacting on climate, urban air quality and long-range transport of pollutants such as Polycyclic Aromatic Hydrocarbons (PAHs).

scholarly journals Supplementary material to "Atmospheric aerosol deposition fluxes over the Atlantic Ocean: A GEOTRACES case study"

2018 ◽  
Author(s):  
Jan-Lukas Menzel Barraqueta ◽  
Jessica K. Klar ◽  
Martha Gledhill ◽  
Christian Schlosser ◽  
Rachel Shelley ◽  
...  
Keyword(s):  
Atlantic Ocean ◽  
Atmospheric Aerosol ◽  
Aerosol Deposition ◽  
Deposition Fluxes ◽  
Supplementary Material

scholarly journals Effect of pH on the interaction of botulinum neurotoxins A, B and E with liposomes

1989 ◽  
Vol 259 (1) ◽  
pp. 47-53 ◽  
Author(s):  
C Montecucco ◽  
G Schiavo ◽  
B R Dasgupta
Keyword(s):  
Fatty Acid ◽  
Botulinum Neurotoxin ◽  
Structural Changes ◽  
Polar Region ◽  
Low Ph ◽  
Hydrophobic Core ◽  
Head Groups ◽  
Botulinum Neurotoxins ◽  
Ph Range ◽  
Lipid Interaction

The interaction of botulinum neurotoxin serotypes A, B and E with membranes of different lipid compositions was examined by photolabelling with two photoreactive phosphatidylcholine analogues that monitor the polar region and the hydrophobic core of the lipid bilayer. At neutral pH the neurotoxins interacted both with the polar head groups and with fatty acid chains of phospholipids. At acidic pHs the neurotoxins underwent structural changes characterized by a more extensive interaction with lipids. Both the heavy and light chain subunits of the neurotoxins were involved in the process. The change in the nature and extent of toxin-lipid interaction occurred in the pH range 4-6 and was not influenced by the presence of polysialogangliosides. The present data are in agreement with the idea that botulinum neurotoxins enter into nerve cells from a low pH intracellular compartment.

scholarly journals Mechanochemical synthesis of amorphous and crystalline Na2P2S6 – elucidation of local structural changes by X-ray total scattering and NMR

2020 ◽  
Vol 49 (5) ◽  
pp. 1668-1673
Author(s):  
Charlotte Fritsch ◽  
Anna-Lena Hansen ◽  
Sylvio Indris ◽  
Michael Knapp ◽  
Helmut Ehrenberg
Keyword(s):  
Molecular Structure ◽  
Mechanochemical Synthesis ◽  
Crystalline State ◽  
Structural Changes ◽  
Total Scattering ◽  
X Ray

Na2P2S6 was synthesized in an amorphous and crystalline state and the molecular structure of the two is significantly different.

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