Physical Sciences and Mathematics Commons^™

Structure-Property-Function Connections Underlying Performance Of Polybenzoxazole Membranes Derived From Bisapaf Polyimides, Maram A. Q. Al-Sayaghi, Jeremy Lewis, Chris Buelke, Ali Alshami

Chemical Engineering Faculty Publications

Highlights

• Stable rigid monomers result in polyimides with higher Mw, Tg, TR, and the more superior separation performance.
• Thermal rearrangement improved ideal gas separation by 1.5 to 2.0 orders of magnitude.
• Thermal rearrangement resulted in an enhanced thermal, mechanical and chemical properties of the produced membranes.

Polymeric membranes remain and will most likely continue to be the most practical cost-effect chemical constructs for gas separation processes, provided that novel polymers are developed to overcome current and persisting limitations facing exiting membranes. Here, we report a methodical and systematic study of the structure-property-function relations of standard polyimide membranes and their implications …

Optimization Of Electrospray Ionization For Liquid Chromatography Time-Of-Flight Mass Spectrometry Analysis Of Preservatives In Wood Leachate Matrix, Kukowski Klara, Gysbers Brianna, Stephen Fisher, Alena Kubatova

Chemistry Faculty Publications

Triazoles and 3-iodo-2-propynyl butylcarbamate (IPBC) are commonly used wood preservatives active against a wide range of fungi and bacteria. As they are prone to leaching, their amounts need to be monitored by the industry to determine preservative loss from the products and for environmental impact assessment. Therefore, a liquid chromatography–electrospray–time-of-flight mass spectrometry (LC–ESI–TOFMS) method was developed and optimized for simultaneous quantification of triazoles and IPBC in aqueous wood extracts, specifically wood leachate. Analyte pre-concentration on a solid-phase extraction cartridge prior to the analysis yielded > 94% recoveries. ESI method parameters (e.g., solvent system, electrolyte type, electrolyte concentration, capillary and fragmentor voltages) …

A Graphene Oxide-Based Fluorescence Assay For Sensitive Detection Of Dna Exonuclease Enzymatic Activity, Xiao Liu, Yingfen Wu, Xu Wu, Julia Zhao

Chemistry Faculty Publications

The 3′–5′ exonuclease enzyme plays a dominant role in multiple pivotal physiological activities, such as DNA replication and repair processes. In this study, we designed a sensitive graphene oxide (GO)-based probe for the detection of exonuclease enzymatic activity. In the absence of Exo III, the strong π–π interaction between the fluorophore-tagged DNA and GO causes the efficient fluorescence quenching via a fluorescence resonance energy transfer (FRET). In contrast, in the presence of Exo III, the fluorophore-tagged 3′-hydroxyl termini of the DNA probe was digested by Exo III to set the fluorophore free from adsorption when GO was introduced, causing an …

The Aromatization Of Propene Via Nano-Size Hzsm-5, Wayne Seames, Swapnil Fegade, Inna Sakodynskaya, Darrin Muggli, Brian Tande, Alena Kubatova, Evguenii Kozliak

Chemistry Faculty Publications

Zeolite (ZSM) catalysts are known to convert small-size alkenes, e.g., propene, into aromatic hydrocarbons, specifically benzene, toluene and xylenes (BTX), with both high efficiency and specificity. The efficiency of conventional and hierarchical nano-size ZSM-5 for propene aromatization was compared in this study using a Design of Experiments (DOE) approach combined with detailed product analysis. Contrary to our expectations, the former showed a significantly greater BTX yield than the latter. Analysis of the obtained data by DOE and additional experiments with soybean oil cracking using both catalyst types indicated that a reason for the observed reduced activity of nano-scale zeolites may …

Lipophilic Chemicals From Diesel Exhaust Particles Trigger Calcium Response In Human Endothelial Cells Via Aryl Hydrocarbon Receptor Non-Genomic Signalling, Alena Kubatova, Bendik C. Brinchmann, Eric Le Ferrec, Normand Podechard, Dominique Lagadic-Gossmann, Kenji F. Shoji, Aubin Penna, Klara Kukowski, Jorn A. Holme, Johan Ovrevik

Chemistry Faculty Publications

Exposure to diesel exhaust particles (DEPs) affects endothelial function and may contribute to the development of atherosclerosis and vasomotor dysfunction. As intracellular calcium concentration [Ca²⁺]_i is considered important in myoendothelial signalling, we explored the effects of extractable organic matter from DEPs (DEP-EOM) on [Ca²⁺]_i and membrane microstructure in endothelial cells. DEP-EOM of increasing polarity was obtained by pressurized sequential extraction of DEPs with n-hexane (n-Hex-EOM), dichloromethane (DCM-EOM), methanol, and water. Chemical analysis revealed that the majority of organic matter was extracted by the n-Hex- and DCM-EOM, with polycyclic aromatic hydrocarbons primarily occurring in n-Hex-EOM. …

Theoretical Circular Dichroism Spectra Of The Α-Helical Protein Calexitin With The Dipole Interaction Model Including The N-Π* Transition, Akongnwi C. Jungong, Tsvetan Aleksandrov, Rahul Nori, Justin Erickson, Kathryn A. Thomasson, Igor V. Uporov, Ethan R. Austhof, Emily Holt, Felix N. Ngassa

Chemistry Faculty Publications

Circular dichroism (CD) is an important structural biology technique used to study protein dynamics, and most especially the secondary structure of peptides and proteins. Although CD is a technique that is relatively easy to introduce to undergraduate students, the high cost of obtaining a conventional CD instrument and the time required for sample preparation prevents a good number of students from having hands-on experiments demonstrating the principle of CD. Herein, theoretical circular dichroism with the dipole interaction model, DInaMo, is proposed as a tool for introducing students to CD. Using the dipole interaction model, the CD spectra of an α-helical …

A Novel Chemosynthetic Peptide With Β-Sheet Motif Efficiently Kills Klebsiella Pnuemoniae In A Mouse Model, Shirui Tan, Changpei Gan, Rongpeng Li, Yan Ye, Shuang Zhang, Xu Wu, Yi Yan Yang, Weimin Fan, Min Wu

Chemistry Faculty Publications

Klebsiella pneumoniae (Kp) is one of the most common pathogens in nosocomial infections and is increasingly becoming multiple drug resistant. However, the molecular pathogenesis of Kp in causing tissue injury and dysregulated host defense remains elusive, further dampening the development of novel therapeutic measures. We have previously screened a series of synthetic antimicrobial beta-sheet forming peptides and identified a peptide (IRIKIRIK; ie, IK8L) with a broad range of bactericidal activity and low cytotoxicity in vitro. Here, employing an animal model, we investigated the antibacterial effects of IK8L in acute infection and demonstrated that peritoneal injection of IK8L to mice down-regulated …