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Full-Text Articles in Physical Sciences and Mathematics

Phosphate Esters, Thiophosphate Esters And Metal Thiophosphates As Lubricant Additives, David W. Johnson, John E. Hils Dec 2013

Phosphate Esters, Thiophosphate Esters And Metal Thiophosphates As Lubricant Additives, David W. Johnson, John E. Hils

Chemistry Faculty Publications

Phosphate esters, thiophosphate esters and metal thiophosphates have been used as lubricant additives for over 50 years. While their use has been extensive, a detailed knowledge of how they work has been a much more recent development. In this paper, the use of phosphate esters and thiophosphate esters as anti-wear or extreme pressure additives is reviewed with an emphasis on their mechanism of action. The review includes the use of alkyl phosphates, triaryl phosphates and metal containing thiophosphate esters. The mechanisms of these materials interacting with a range of iron and steel based bearing material are examined.


Molecular Level Interaction Of Human Fibroblast Growth Factor-1 (Hfgf-1) With Phloridzin, Rammohan Paripelly Dec 2013

Molecular Level Interaction Of Human Fibroblast Growth Factor-1 (Hfgf-1) With Phloridzin, Rammohan Paripelly

Masters Theses & Specialist Projects

Fibroblast growth factors (FGFs) are a family of growth factors which includes twenty three proteins. FGFs work as modulators for various cellular activities like mitosis, differentiation and survival. Among the FGF family, human fibroblast growth factor-1 (hFGF-1), which is also known as acidic fibroblast growth factor, is a potent angiogenic agent, involved in the formation of new blood vessels in various tissues. hFGF-1 is regarded as a prototype of the FGF family. It serves as one of the potential targets in tumor inhibition and obesity due to its involvement in new blood vessel formation in cancerous regions and adipose tissues. …


Structure, Theoretical Studies And Coupling Reactions Of Some New Cyclic Boronic Esters, Andrew Kuttler, Sravanthi Durganala, Albert Fratini, Alexander Morgan, Vladimir Benin Sep 2013

Structure, Theoretical Studies And Coupling Reactions Of Some New Cyclic Boronic Esters, Andrew Kuttler, Sravanthi Durganala, Albert Fratini, Alexander Morgan, Vladimir Benin

Chemistry Faculty Publications

The present report describes the X-ray structural and theoretical studies of some new pinacolboronate esters, and it also outlines the use of the target structures in Suzuki coupling reactions to produce new aromatic or heteroaromatic esters and amides. X-ray structural analysis of the studied compounds revealed that the pinacolborane ring's position with respect to the benzene ring varies, depending on the particular environment. An ortho-positioned carboxylic ester (methyl ester) causes a nearly perpendicular orientation of the pinacolborane unit with respect to the benzene ring, whereas an ortho-positioned amide (N,N-dimethylamide) causes the pinacolborane unit to orient itself nearly coplanar. A plausible …


Characterization By Nmr Of Reactants And Products Of Hydrofluoroether Isomers, Cf3(Cf2)3och3 And (Cf3)2c(F)Cf2och3, Reacting With Isopropyl Alcohol, Howard Knachel, Vladimir Benin, William E. Moddeman, Janine C. Birkbeck, Thomas A. Kestner, Tayna L. Young Jul 2013

Characterization By Nmr Of Reactants And Products Of Hydrofluoroether Isomers, Cf3(Cf2)3och3 And (Cf3)2c(F)Cf2och3, Reacting With Isopropyl Alcohol, Howard Knachel, Vladimir Benin, William E. Moddeman, Janine C. Birkbeck, Thomas A. Kestner, Tayna L. Young

Chemistry Faculty Publications

The 3M Company product Novec™ 71IPA DL, a mixture of methoxyperfluorobutane, methoxyperfluoroisobutane and 4.5 wt.% isopropyl alcohol, has been found to be very stable at ambient temperature, producing fluoride at the rate of ~1 ppm/year. Our earlier kinetic and theoretical studies have identified the reaction mechanism. This paper identifies the 1H and 19F NMR chemical shifts, multiplicities, and coupling constants of reactants and the major products that result from aging the mixture in sealed Pyrex NMR tubes for periods up to 1.8 years at temperatures from 26 °C to 102 °C. Chemical shifts and coupling constants of fluorine …


Interaction Between Lubricants Containing Phosphate Ester Additives And Stainless Steels, David W. Johnson, Matthew Bachus, John E. Hils May 2013

Interaction Between Lubricants Containing Phosphate Ester Additives And Stainless Steels, David W. Johnson, Matthew Bachus, John E. Hils

Chemistry Faculty Publications

One way to improve fuel efficiency in today’s jet aircraft engines is to create an environment for higher operating temperatures and speeds. New and improved lubricants and bearing materials must be developed to remain stable in these elevated operating temperatures. Three lubricants, with varying amounts of tricresyl phosphate added as an anti-wear/extreme pressure additive were tested on two different stainless steels at varying temperatures ranging from 300 °C to 350 °C in vacuum. Significant decomposition of the lubricant base-stocks and the phosphate ester additive did occur in most of the trials resulting in the formation of carboxylic acids and phenols. …


Study Of The Insulin Mimetic Sodium Orthovanadate In Glucosamine Induced Insulin Resistnace In Primary Rat Hepatocytes, Kalan Mcpherson Apr 2013

Study Of The Insulin Mimetic Sodium Orthovanadate In Glucosamine Induced Insulin Resistnace In Primary Rat Hepatocytes, Kalan Mcpherson

Masters Theses

Insulin resistance and type II diabetes is a disease state characterized by a lack of sensitivity of insulin to provoke a proper response in insulin sensitive tissues. Currently, we utilize glucosamine to increase flux through the Hexosamine Biosynthetic Pathway (HBP) to induce an insulin resistance like state in primary rat hepatocytes. We tested the effectiveness of the insulin mimetic sodium orthovanadate to determine if it could elicit an insulin-like response under these conditions. Mixed results were obtained on the effectiveness of vanadate as an insulin mimetic in this insulin resistant model.


Development Of Affinity Microcolumns For Drug–Protein Binding Studies In Personalized Medicine: Interactions Of Sulfonylurea Drugs With In Vivo Glycated Human Serum Albumin, Jeanethe Anguizola, K. S. Joseph, Omar S. Barnaby, Ryan Matsuda, Guadalupe Alvarado, William Clarke, Ronald Cerny, David S. Hage Jan 2013

Development Of Affinity Microcolumns For Drug–Protein Binding Studies In Personalized Medicine: Interactions Of Sulfonylurea Drugs With In Vivo Glycated Human Serum Albumin, Jeanethe Anguizola, K. S. Joseph, Omar S. Barnaby, Ryan Matsuda, Guadalupe Alvarado, William Clarke, Ronald Cerny, David S. Hage

David Hage Publications

This report used high-performance affinity microcolumns to examine the changes in binding by sulfonylurea drugs to in vivo glycated HSA that had been isolated from individual patients with diabetes. An immunoextraction approach was developed to isolate HSA and glycated HSA from clinical samples, using only 20 μL of plasma or serum and 6–12 nmol of protein to prepare each affinity microcolumn. It was found that the affinity microcolumns could be used in either frontal analysis or zonal elution studies, which typically required only 4–8 min per run. The microcolumns had good stability and allowed data to be obtained for multiple …


Preparation Of Phosphonoterephthalic Acids Via Palladium-Catalyzed Coupling Of Aromatic Iodoesters, Nathaniel Ivan, Vladimir Benin, Alexander Morgan Jan 2013

Preparation Of Phosphonoterephthalic Acids Via Palladium-Catalyzed Coupling Of Aromatic Iodoesters, Nathaniel Ivan, Vladimir Benin, Alexander Morgan

Chemistry Faculty Publications

The current article reports in detail the preparation of two phosphonoterephthalic acids: 2-phosphonoterephthalic acid (1) and 2,5-diphosphonoterephthalic acid (2). Efficient, scalable syntheses have been developed for both compounds based on Pd-catalyzed coupling reactions of iodinated terephthalate esters. Phosphonoterephthalic acids are potentially useful as flame-retardant additives or as monomers for the construction of acid-pendant polymer chains.


Reaction Between Polyol-Esters And Phosphate Esters In The Presence Of Metal Carbides, David W. Johnson, Carolyn Iacullo, John E. Hils Jan 2013

Reaction Between Polyol-Esters And Phosphate Esters In The Presence Of Metal Carbides, David W. Johnson, Carolyn Iacullo, John E. Hils

Chemistry Faculty Publications

The reaction of metal carbides with polyol esters found in aerospace lubricants and phosphate esters commonly used as additives was investigated. Carbides were of particular interest since modern materials under consideration at high temperature bearings have surfaces that are primarily metal carbides. Vanadium and chromium carbide were found to react with the ester and phosphate ester by a transesterification reaction, producing an alkyl phosphate which is less stable than the aromatic phosphate esters. In the process, the metal carbide is converted to the metal phosphate and metal polyphosphate, evidenced by the infrared and Raman spectra of the solid residue and …


Time-Stepping For Laser Ablation, Harihar Khanal, David Autrique, Vasilios Alexiades Jan 2013

Time-Stepping For Laser Ablation, Harihar Khanal, David Autrique, Vasilios Alexiades

Publications

Nanosecond laser ablation is a popular technique, applied in many areas of science and technology such as medicine, archaeology, chemistry, environmental and materials sciences. We outline a computational model for radiative and collisional processes occurring during ns-laser ablation, and compare the performance of various low and high order time-stepping algorithms.


Hydrodynamic Modeling Of Ns-Laser Ablation, David Autrique, Vasilios Alexiades, Harihar Khanal Jan 2013

Hydrodynamic Modeling Of Ns-Laser Ablation, David Autrique, Vasilios Alexiades, Harihar Khanal

Publications

Laser ablation is a versatile and widespread technique, applied in an increasing number of medical, industrial and analytical applications. A hydrodynamic multiphase model describing nanosecond-laser ablation (ns- LA) is outlined. The model accounts for target heating and mass removal mechanisms as well as plume expansion and plasma formation. A copper target is placed in an ambient environment consisting of helium and irradiated by a nanosecond-laser pulse. The effect of variable laser settings on the ablation process is explored in 1-D numerical simulations.


Amalgamation Of Nucleosides And Amino Acids In Antibiotic Biosynthesis, Sandra H. Barnard Jan 2013

Amalgamation Of Nucleosides And Amino Acids In Antibiotic Biosynthesis, Sandra H. Barnard

Theses and Dissertations--Pharmacy

The rapid increase in antibiotic resistance demands the identification of novel antibiotics with novel targets. One potential antibacterial target is the biosynthesis of peptidoglycan cell wall, which is both ubiquitous and necessary for bacterial survival. Both the caprazamycin-related compounds A-90289 and muraminomicin, as well as the capuramycin-related compounds A-503083 and A-102395 are potent inhibitors of the translocase I enzyme, one of the key enzymes required for cell wall biosynthesis. The caprazamycin-related compounds contain a core nonproteinogen b-hydroxy-a-amino acid referred to as 5’-C-glycyluridine (GlyU). Residing within the biosynthetic gene clusters of the aforementioned compounds is a shared open reading …