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Gradient Temperature Raman Spectroscopy of Fatty Acids with One to Six Double Bonds Identifies Specific Carbons and Provides Systematic Three Dimensional Structures

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Journal of Biophysical Chemistry 2018年第1期9卷 1-14页

作者： C. Leigh Broadhurst Walter F. Schmidt julie k. nguyen Jianwei Qin k.anglin Chao Moon S. k.m Environmental Microbiology and Food Safety Laboratory US Department of Agriculture Agricultural Research Service Beltsville MD USA Department of Mechanical Engineering University of Maryland Baltimore County Baltimore MD USA

Specialized pro-resolving mediators provide promising targets for new drugs and natural products. Much work.has been accomplished on the structure/ function of the lipoxygenase and cyclooxygenase enzymes but not on the substrates. A better visualization of three-dimensional lipid structures will allow increased refinement of the interactions that produce the pro-resolving mediators, and lead to improvements in synthetic pathways. We present systematic analysis of oleic (18:1n-9), linoleic (18:2n-6), alpha-linolenic (18:3n-3), arachidonic (20:4n-6), docosapentaenoic (22:5n-3), and docosahexaenoic (22:6n-3) acids. Continuous gradient temperature Raman spectroscopy (GTRS) applies the temperature gradients utilized in differential scanning calorimetry to Raman spectroscopy. GTRS can identify and differentiate specific carbon chain sites, finally allowing Raman analysis to explain why the long-chain polyunsaturated fatty acids (LC-PUFA) exhibit such extreme functional differences despite minimal changes in chemical structure. Detailed vibrational analysis of the important frequency ranges 1450 - 1200 cm-1 (includes CH2 bending and twisting) and 1750 - 1425 cm-1 (includes C=C stretching and C-C stretching plus H-C in-plane rock.ng) shows for the first time that each molecule has its own characteristic set of modes with only some redundancy/commonality. The number and frequency of modes correlates with three-dimensional molecular structure, not the degree of unsaturation. The high degree of specificity of lipoxygenase and cyclooxygenase enzymes should be reconsidered in light of the fact that individual sites on the polyunsaturated fatty acid chain are nonequivalent, and each LC-PUFA molecule has an individual, specific three dimensional structure incorporating torsion.

关键词： Gradient Temperature Raman Spectroscopy Raman Spectroscopy Arachidonic Acid Docosapentaenoic Acid Docosahexaenoic Acid Alpha-Linolenic Acid N-3DPA DHA GTRS

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Environmental Assessment and Dielectric Performances of the Secondary Electrical Insulation in Low Voltage Motors Impregnated by Different Techniques

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Engineering（科研） 2017年第10期9卷 860-873页

作者： Manh Quan nguyen Simon Dario David Malec Dominique Mary Jean-Pascal Cambronne Damien Prunel julie Orgelet LAPLACE Université de Toulouse CNRS INPT UPS Toulouse France Bureau Véritas Moirans France

A recent technique, using to potentially replace the conventional impregnating one in low voltage electric motors, has been studied in this communication. The conventional technique that uses?both primary and secondary insulations;?i.e.: enamel and varnish, has been compared to this recent technique which only uses one component,?i.e.: self-bonding wires. Self-bonding wires polymerization is very quick.compared to that of the conventional technique. Environmental impact and both dielectric and mechanical properties of these two techniques have been estimated and compared. The goal is to estimate if this recent technique has not only a better environmental footprint but also good technical properties. The dielectric properties that have been measured are the dielectric strength and?the lifetime under pulse?voltage while mechanical consists in measuring the bonding strength that is crucial for impregnation.?For that purpose, a Life Cycle Assessment (LCA) that can simultaneously evaluatenumerous impacts on ground, water and air,?has been performed. The results show clearly that the recent technique significantly reduces the environmental footprint. Both mechanical and dielectric properties are then compared and analyzed.

关键词： Electrical Motor Enameled Wire Self-Bonding Wire Impregnation Tech-nique Dielectric Performance Environmental Impact

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