scholarly journals Evaluation of Friction Behavior and Surface Interactions of Cyano-Based Ionic Liquids under Different Sliding Contacts and High Vacuum Condition

Lubricants ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 69 ◽  
Author(s):  
Shouhei Kawada ◽  
Seiya Watanabe ◽  
Shinya Sasaki ◽  
Masaaki Miyatake
Keyword(s):  
Mass Spectrometry ◽  
Ionic Liquids ◽  
High Vacuum ◽  
Mass Spectrometry Analysis ◽  
Low Friction ◽  
Friction Behavior ◽  
Friction Coefficients ◽  
Spectrometry Analysis ◽  
Worn Surface ◽  
Nascent Surface

The friction coefficients of ionic liquids were evaluated by many investigations. Most investigations used fluorine-based ionic liquids as lubricants. However, these ionic liquids produce the corrosion wear. This investigation focuses on the use of cyano-based ionic liquids as lubricants. Compared to fluorine-based ionic liquids, cyano-based ionic liquids exhibit high friction coefficients against steel material. This work examines how the friction coefficients of cyano-based ionic liquids are influenced by the type of sliding material used (AISI 52100, TiO2, and tetrahedral amorphous carbon). TiO2 lubricated with 1-ethyl-3-methylimidazolium tricyanomethanide, and ta-C lubricated with 1-butyl-1methylpyrrolidinium tetracyanoborate exhibited very low friction coefficients, smaller than fluorine-based ionic liquids. Time-of-Flight Secondary Ion Mass Spectrometry analysis showed that anions adsorb onto the worn surface, suggesting that anion adsorption is a critical parameter influencing friction coefficients. Quadrupole Mass Spectrometry measurements revealed that cations decompose on the nascent surface, preventing adsorption on the worn surface. These results suggest that low friction coefficients require the decomposition of cations and adsorption of anions. The reactivity of nascent surface changes with the sliding material used due to varying catalytic activity of the nascent surfaces.

The cation−anion interaction in ionic liquids studied by extractive electrospray ionization mass spectrometry

2014 ◽  
Vol 92 (7) ◽  
pp. 611-615 ◽  
Author(s):  
Yafei Zhou ◽  
Junfeng Zhan ◽  
Xiang Gao ◽  
Cao Li ◽  
Konstantin Chingin ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Ionic Liquid ◽  
Ionic Liquids ◽  
Electrospray Ionization ◽  
Electrospray Ionization Mass Spectrometry ◽  
Mass Spectrometry Analysis ◽  
Ionization Mass Spectrometry ◽  
Supramolecular Organization ◽  
Ionization Mass ◽  
Spectrometry Analysis

Ionic liquids, known as green solvents, are of sustainable interest in modern chemistry, industry, and many other fields. Here, extractive electrospray ionization has been applied to transfer various room temperature ionic liquids into the gas phase for mass spectrometry analysis. Generated mass spectra display free cations (C+), anions (A–), and small salt clusters, such as C2A+ and CA2–, from strongly diluted ionic liquid samples (<10−8 mol/L) with high sensitivity and tolerance to chemical contamination. The eight ionic liquids based on the 1-butyl-3-methylimidazolium cation with different anions (OH–, HSO4–, Cl–, BF4–, AlCl4–, NO3–, Ac–, and PF6–) are investigated in the present work. Interestingly, the 1-butyl-3-methylimidazolium cation signal intensity is inversely correlated with the hydrogen bonding strength between the anion and cation. Our study indicates that the direct extractive electrospray ionization mass spectrometry analysis is a convenient method to screen ionic liquid libraries with regard to chemical composition, physicochemical properties, and supramolecular organization of ionic liquids.

scholarly journals Effect of Ocular Hypertension on D-β-Aspartic Acid-Containing Proteins in the Retinas of Rats

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Takashi Kanamoto ◽  
Takashi Tachibana ◽  
Yasushi Kitaoka ◽  
Toshio Hisatomi ◽  
Yasuhiro Ikeda ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Ocular Hypertension ◽  
Aspartic Acid ◽  
Atp Synthase ◽  
Wistar Rats ◽  
Protein Band ◽  
Mass Spectrometry Analysis ◽  
Liquid Chromatography Mass Spectrometry ◽  
Spectrometry Analysis ◽  
Sds Page

Purpose. To investigate the effect of ocular hypertension-induced isomerization of aspartic acid in retinal proteins. Methods. Adult Wistar rats with ocular hypertension were used as an experimental model. D-β-aspartic acid-containing proteins were isolated by SDS-PAGE and western blot with an anti-D-β-aspartic acid antibody and identified by liquid chromatography-mass spectrometry analysis. The concentration of ATP was measured by ELISA. Results. D-β-aspartic acid was expressed in a protein band at around 44.5 kDa at much higher quantities in the retinas of rats with ocular hypertension than in those of normotensive rats. The 44.5 kDa protein band was mainly composed of α-enolase, S-arrestin, and ATP synthase subunits α and β, in both the ocular hypertensive and normotensive retinas. Moreover, increasing intraocular pressure was correlated with increasing ATP concentrations in the retinas of rats. Conclusion. Ocular hypertension affected the expression of proteins containing D-β-aspartic acid, including ATP synthase subunits, and up-regulation of ATP in the retinas of rats.

scholarly journals N-Terminomics Strategies for Protease Substrates Profiling

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4699
Author(s):  
Mubashir Mintoo ◽  
Amritangshu Chakravarty ◽  
Ronak Tilvawala
Keyword(s):  
Mass Spectrometry ◽  
Protease Activity ◽  
Viral Infections ◽  
Mass Spectrometry Analysis ◽  
Post Translational Modification ◽  
Spectrometry Analysis ◽  
Physiological Conditions ◽  
Inflammatory Conditions ◽  
Biological Mixtures

Proteases play a central role in various biochemical pathways catalyzing and regulating key biological events. Proteases catalyze an irreversible post-translational modification called proteolysis by hydrolyzing peptide bonds in proteins. Given the destructive potential of proteolysis, protease activity is tightly regulated. Dysregulation of protease activity has been reported in numerous disease conditions, including cancers, neurodegenerative diseases, inflammatory conditions, cardiovascular diseases, and viral infections. The proteolytic profile of a cell, tissue, or organ is governed by protease activation, activity, and substrate specificity. Thus, identifying protease substrates and proteolytic events under physiological conditions can provide crucial information about how the change in protease regulation can alter the cellular proteolytic landscape. In recent years, mass spectrometry-based techniques called N-terminomics have become instrumental in identifying protease substrates from complex biological mixtures. N-terminomics employs the labeling and enrichment of native and neo-N-termini peptides, generated upon proteolysis followed by mass spectrometry analysis allowing protease substrate profiling directly from biological samples. In this review, we provide a brief overview of N-terminomics techniques, focusing on their strengths, weaknesses, limitations, and providing specific examples where they were successfully employed to identify protease substrates in vivo and under physiological conditions. In addition, we explore the current trends in the protease field and the potential for future developments.

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