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The asphalts were aged at different ageing levels to simulate oxidative ageing evolution. The changes in the four components and chemical functional groups of the asphalts at different ageing stages were analysed, and their corresponding asphalt molecular models were established. Then, the self-healing molecular models during ageing evolution were established based on the asphalt molecular models. The self-healing characteristics of the virgin, fast-aging, slow-aging and full-aging stages were studied using the density, radial distribution function (RDF), energy, relative concentration and diffusion coefficients. The results show that the characteristic peak values of RDF curves at the same distance increase with ageing. The bond energy increases less in the fast-ageing stage but greatly in the slow-ageing stage, due to limited sulphur atoms in the asphalt molecule, while the non-bond energy increases greatly in the fast-ageing stage, and less in the slow-ageing stage, due to the stronger polarity of sulphoxide. The relative concentration of saturate changes most, and asphaltene changes less, aromatic and resins change evenly during ageing. The decrease rate of the diffusion coefficient of saturate, aromatic, resin and asphaltene is 12.6%, 11.12%, 10.42% and 9.2% in the fast-ageing stage and 0.62%, 0.60%, 0.55% and 0.62% in the slow-ageing stage. [ABSTRACT FROM AUTHOR]

The performance of SBS-modified asphalt (SBSMA) deteriorates seriously due to aging. In this research, aging evolution experiments were conducted on base asphalt (BA) and its SBSMA. The rheological and fatigue properties of BA and SBSMA with different aging degrees were assessed through a series of Dynamic Shear Rheometer (DSR) tests. The changes in the chemical functional group and the morphology of BA and SBSMA were analysed through the Fourier Transform infra-red spectroscopy (FTIR) and the fluorescence microscope to elucidate aging evolution mechanisms. The results show that the aging process for BA and SBSMA can be divided into two stages, the first aging rate is fast and the second aging rate is slow. The SBS degradation in SBSMA occurs primarily in the first aging stage, which shortens the rapid changes of rutting resistance and creep performance for SBSMA and enhance its high-temperature stability. The fatigue life of SBSMA increases by almost one order of magnitude larger than the BA due to SBS under the same aging time. The fatigue life of BA and SBSMA increases rapidly first and then slowly during aging, moreover, the external forces also have a certain impact on the fatigue life. [ABSTRACT FROM AUTHOR]

Asphalt oxidation kinetic aging effect on the adhesion behavior of asphalt-aggregate interfaces at atomistic scale was investigated in this study. The asphalts were aged at different aging durations. The sulfoxide and carbonyl functional group content as well as SARA fractions of the asphalts at different aging times were studied through the tests of Fourier Transform Infrared Spectroscopy (FTIR) and Saturate, Aromatic, Resin and Asphaltene (SARA) fractions. Asphalt molecular models of virgin, rapid-rate aged, slow-rate aged and full-aged were established based on SARA fractions and FTIR results, to construct asphalt quartz and asphalt-calcite interface systems at different aging stages. The simulation results showed that the nanostructure of asphalt is influenced by the aggregate type and asphalt oxidative aging. The growth rates of adhesion energy of asphalt-quartz and asphalt-calcite systems increase rapidly first and then slowly with aging time, but the growth rates are different. Meanwhile, the Van der Waals energy is the major energy source of adhesion energy, and the contribution of van der Waals and electrostatic energy to adhesion energy is different. The aging of asphaltene and resin promotes the adhesion ability to quartz or calcite, while the aging of aromatic components is not conducive and the saturate has almost no effect. [ABSTRACT FROM AUTHOR]

Performance of asphalt concrete pavement significantly degrades during the aging of asphalt binders. The master curves of complex shear modulus and phase angle are recognised as useful tools to characterise the rheological properties of aging asphalt binders. The main shortcoming of existing master curves is that the effects of aging cannot be captured and predicted effectively. This study developed a new method to construct such aging master curves that can be extended to predict the complex shear modulus and phase angle at a wide range of aging time and temperature. The DSR tests were conducted on three different types of asphalt binders with three aging temperatures and four aging durations. The master curves of complex shear modulus and phase angle were constructed for aging asphalt binders through time-temperature-aging shift by performing both rotation and horizontal aging shift. Rotation and horizontal aging shift were determined as the function of aging time and aging temperature. Therefore, it becomes possible and convenient to construct single aging master curves at a wide range of aging temperature and aging time. [ABSTRACT FROM AUTHOR]

This study proposed a rapid method to predict rheological characteristics of asphalt binders due to oxidative aging based on pressure aging vessel (PAV) as the accelerating aging tool. Six types of asphalt binders were aged at various temperatures for different durations with two aging methods, which were oven aging under standard atmosphere, and PAV aging under a pressure of 2.1MPa. The crossover modulus was determined to characterize the rheological property changes with respect to aging. The oxidation aging kinetics model in terms of crossover modulus under oven aging method was developed, the model parameters showed universal correlations of each other. The aging kinetics model parameters using PAV aging method also obtained. Relationship between the aging kinetics model parameter in oven and PAV aging was established. The activation energy as one of the aging kinetics model parameters in oven aging calculated from PAV data using the relationship, along with the universal correlations of aging kinetics model parameter in oven aging, the crossover modulus predicted rapidly and accurately. Such a rapid method is capable of predicting the aging behavior and rheological properties of asphalt binder subjected to oxidation, and is significantly save a great deal of time and effort in the laboratory. [ABSTRACT FROM AUTHOR]

Protein kinase C (PKC) is a family of lipid-activated enzymes involved in anesthetic preconditioning signaling pathways. Previously, n-alkanols and general anesthetics have been found to activate PKC by binding to the kinase C1B subdomain. In the present study, we attempt to ascertain the molecular mechanism and interaction mode of human PKCα C1B subdomain with a variety of exogenous n-alkanols and volatile general anesthetics as well as endogenous activator phorbol ester (PE) and co-activator diacylglycerol (DG). Systematic bioinformatics analysis identifies three spatially vicinal sites on the subdomain surface to potentially accommodate small-molecule ligands, where the site 1 is a narrow, amphipathic pocket, the site 2 is a wide, flat and hydrophobic pocket, and the site 3 is a rugged, polar pocket. Further interaction modeling reveals that site 1 is the cognate binding region of natural PE activator, which can moderately simulate the kinase activity in an independent manner. The short-chain n-alkanols are speculated to also bind at the site to competitively inhibit PE-induced kinase activation. The long-chain n-alkanols and co-activator DG are found to target site 2 in a nonspecific manner, while the volatile anesthetics prefer to interact with site 3 in a specific manner. Since the site 1 is composed of two protein loops that are also shared by sites 2 and 3, binding of n-alkanols, DG and anesthetics to sites 2 and 3 can trigger a conformational displacement on the two loops, which enlarges the pocket size and changes the pocket configuration of site 1 through an allosteric mechanism, consequently enhancing kinase activation by improving PE affinity to the site. [ABSTRACT FROM AUTHOR]

This study demonstrated that dopaminergic MN9D and PC12 cells were more vulnerable than non-dopaminergic N2A cells to the challenge by proteasome inhibitor MG132, which could be alleviated by reductants and alpha-methyl tyrosine (alpha-MT), a specific tyrosine hydroxylase inhibitor. Furthermore, challenging non-dopaminergic N2A cells with exogenous DA could aggravate MG132-induced cell viability decrease, which could be abrogated by reductants but not by alpha-MT. It was observed that alpha-MT could decrease endogenous DA content in dopaminergic MN9D and PC12 cells while N2A cells could take in exogenous DA into cytosol. The endogenous DA in dopaminergic cells was demonstrated to inhibit proteasome activity in the cells and further sensitize the proteasome to MG132 inhibition. In addition, the endogenous DA was also implicated for the increased level of lipid peroxidation and ubiquitinated proteins as well as inclusion bodies formation when non-dopaminergic cells were challenged with exogenous DA. Taken together it is proposed that endogenous DA in dopaminergic neurons could promote selective dopaminergic neurodegeneration, especially under the conditions of exopathic or idiopathic defects of ubiquitin-proteasome system (UPS), which may be abolished by reductant remedy. [ABSTRACT FROM AUTHOR]

Gymnothorax minor has been often confused with G. reticularis because of the similar morphological characteristics. The complete mitochondrial genome sequence of G. minor is 16,575 bp in length, including 13 protein-coding genes, two ribosomal RNA genes, 22 transfer RNA genes, and two non-coding regions (CR and OL). All the protein-coding genes use ATG as start codon except COI using GTG. Most of them have complete stop codon as stop codon while COII and ND4 use T(aa). Phylogenetic analysis showed G. minor first clustered together with congeneric species and formed a monophyly in species of the genus Gymonthrax. [ABSTRACT FROM AUTHOR]