Temperature-induced oligomerization of polycyclic aromatic hydrocarbons (PAHs) was found at 500-773 K and ambient and high (3.5 GPa) pressures. The most intensive oligomerization at 1 bar and 3.5 GPa occurs at 740-823 K. PAH carbonization at high pressure is the final stage of oligomerization and occurs as a result of sequential oligomerization and polymerization of the starting material, caused by overlapping of π-orbitals, a decrease of intermolecular distances, and finally the dehydrogenation and polycondensation of benzene rings. Being important for building blocks of life, PAHs and their oligomers can be formed in the interior of the terrestrial planets with radii less than 2270 km.
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http://dx.doi.org/10.1038/s41598-017-08529-2 | DOI Listing |
J Phys Chem B
May 2023
Department of Physics, Laser Research Institute, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa.
We report on the structure of Gramicidin S (GS) in a model membrane mimetic environment represented by the amphipathic solvent 1-octanol using one-dimensional (1D) and two-dimensional (2D) IR spectroscopy. To explore potential structural changes of GS, we also performed a series of spectroscopic measurements at differing temperatures. By analyzing the amide I band and using 2D-IR spectral changes, results could be associated to the disruption of aggregates/oligomers, as well as structural and conformational changes happening in the concentrated solution of GS.
View Article and Find Full Text PDFBiochim Biophys Acta Gen Subj
February 2023
Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, USA; Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA. Electronic address:
Here we present evidence, based on alterations of its intrinsic tryptophan fluorescence, that UBQLN2 protein undergoes a conformational switch when the temperature is raised from 37 °C to 42 °C. The switch is reset on restoration of the temperature. We speculate that the switch regulates UBQLN2 function in the heat shock response because elevation of the temperature from 37 °C to 42 °C dramatically increased in vitro binding between UBQLN2 and HSPA1B.
View Article and Find Full Text PDFSci Total Environ
June 2021
Department of Epidemiology and Health Statistics, School of Public Health, Anhui Medical University, Hefei, Anhui, China; Inflammation and Immune Mediated Diseases Laboratory of Anhui Province, China. Electronic address:
Background: Temperature stress was reported to impact the gut-brain axis including intestinal microbiome and neuroinflammation, but the molecular markers involved remain unclear. We aimed to examine the effects of different temperature stress on the intestinal microbiome and central nucleotide-binding oligomerization domain-like receptor family pyrin domain containing 3 (NLRP3) inflammasomes.
Materials And Methods: Mice models were established under low temperature (LT), room temperature (RT), high temperature (HT), and temperature variation (TV) respectively for seven days.
Small heat shock proteins (sHSPs) are ubiquitous molecular chaperones preventing the irreversible denaturation of proteins. While in two sHSPs IbpA and IbpB work in strong cooperation, the sole Mollicute with free-living ability carries a single gene encoding the sHSP protein IbpA. , independently of the temperature, IbpA forms a heterogeneous mixture of approximately 24-mer globules, fibrils and huge protein aggregates.
View Article and Find Full Text PDFNanoscale
November 2019
Centre Énergie, Matériaux et Télécommunications, Institut National de la Recherche Scientifique, 1650 Boulevard Lionel-Boulet, Varennes, Québec, Canada J3X 1S2.
The formation of ordered molecular structures on surfaces is determined by the balance between molecule-molecule and molecule-substrate interactions. Whether the aggregation process is guided by non-covalent forces or on-surface reactions, a deeper understanding of these interactions is pivotal to formulating a priori predictions of the final structural features and the development of bottom-up fabrication protocols. Theoretical models of molecular systems corroborate the information gathered through experimental observations and help explain the thermodynamic factors that underpin on-surface phase transitions.
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