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Tay G.C.,University of California at Irvine | Tay G.C.,Rockford University | Sizemore N.,University of California at Irvine | Sizemore N.,University of Scranton | Rychnovsky S.D.,University of California at Irvine
Organic Letters | Year: 2016

Progress toward understanding the scope and diastereoselectivity of intramolecular Diels-Alder reactions using 2-cyano-1-azadienes is described herein. The resulting cyanoenamine products are underutilized intermediates in organic synthesis. Assembly of the Diels-Alder precursors was achieved using an improved imine condensation/oxidative cyanation protocol. By this method, several highly substituted indolizidine and quinolizidine architectures were constructed. Quantum mechanical DFT calculations at the B3LYP/6-31+G(d) level of theory were performed for these cyclizations and provide insights into the origins of the observed diastereoselectivities. © 2016 American Chemical Society. Source

Marsili R.,Rockford University | Laskonis C.,Rockford University
Lipid Technology | Year: 2014

Flavours and off-flavours in foods are caused by volatile odour-active chemicals. Odour characteristics and thresholds can be strongly influenced by odour synergy effects. For example, in this study, the fishy malodour associated with DHA and EPA oxidation products is the result of odour synergy effects. When two lipid oxidation products - heptanal and (E,Z)-3,5-octadien-2-one - are smelled together, a fishy malodour is perceived. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

Tay G.C.,Rockford University | Tay G.C.,University of California at Irvine | Edwards K.D.,University of California at Irvine
Journal of Chemical Education | Year: 2015

A visual aid teaching tool, the DanceChemistry video series, has been developed to teach fundamental chemistry concepts through dance. These educational videos portray chemical interactions at the molecular level using dancers to represent chemical species. Students reported that the DanceChemistry videos helped them visualize chemistry ideas in a new and memorable way. Surveying the general laboratory course at the University of California, Irvine (n = 1266), 75% of the students said they wanted to use these videos to learn additional chemistry topics in the future. Data from pre- and postsurveys show an increase in students' average scores after watching a 5 min DanceChemistry video. These instructional videos are disseminated broadly through a dedicated YouTube channel, DanceChemistry. © 2015 The American Chemical Society and Division of Chemical Education, Inc. Source

Skwor T.,Rockford University | Skwor T.,Rockford College | Skwor T.,Gannon University | Shinko J.,Gannon University | And 3 more authors.
Applied and Environmental Microbiology | Year: 2014

Members of the genus Aeromonas are ubiquitous in nature and have increasingly been implicated in numerous diseases of humans and other animal taxa. Although some species of aeromonads are human pathogens, their presence, density, and relative abundance are rarely considered in assessing water quality. The objectives of this study were to identify Aeromonas species within Lake Erie, determine their antibiotic resistance patterns, and assess their potential pathogenicity. Aeromonas strains were isolated from Lake Erie water by use of Aeromonas selective agar with and without tetracycline and ciprofloxacin. All isolates were analyzed for hemolytic ability and cytotoxicity against human epithelial cells and were identified to the species level by using 16S rRNA gene restriction fragment length polymorphisms and phylogenetic analysis based on gyrB gene sequences. A molecular virulence profile was identified for each isolate, using multiplex PCR analysis of six virulence genes. We demonstrated that Aeromonas comprised 16% of all culturable bacteria from Lake Erie. Among 119 Aeromonas isolates, six species were identified, though only two species (Aeromonas hydrophila and A. veronii) predominated among tetracycline- and ciprofloxacin-resistant isolates. Additionally, both of these species demonstrated pathogenic phenotypes in vitro. Virulence gene profiles demonstrated a high prevalence of aerolysin and serine protease genes among A. hydrophila and A. veronii isolates, a genetic profile which corresponded with pathogenic phenotypes. Together, our findings demonstrate increased antibiotic resistance among potentially pathogenic strains of aeromonads, illustrating an emerging potential health concern. © 2014, American Society for Microbiology. Source

Marsili R.T.,Rockford University | Laskonis C.R.,Rockford University
Journal of Agricultural and Food Chemistry | Year: 2014

As unsaturated lipids oxidize, they form hydroperoxides, which are susceptible to further oxidation or decomposition to secondary reaction products including aldehydes, ketones, acids, and alcohols. While oxidation reactions of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) are responsible for fishy off-flavors in marine oils, gas chromatography-olfactometry (GC-O) and other types of analytical studies have failed to reveal which specific oxidation products are involved. Previous research (Marsili, R.T.; Laskonis, C. The importance of odourant synergy effects in understanding malodour problems in DHA and EPA products. Lipid Technol. 2014, 26 (2), 31-34) has indicated that fishy malodor may be caused by the presence of two lipid oxidation products, heptanal and (E,Z)-3,5-octadien-2-one. The aims of the present study are to provide experimental method details and offer further evidence that these two oxidation products are indeed the cause of fishy malodors. Initial GC-MS-O studies of marine oils with fishy malodors revealed numerous oxidation products, but none were characterized as fishy. However, when all sample volatiles were captured together and then desorbed simultaneously in GC-O experiments, the fishy malodor was evident, indicating odorant synergy effects were responsible. A simple, novel method was developed using an olfactometry detector as a fraction collector to trap various peaks in marine oil chromatograms. The nose cone of the olfactometry detector was replaced with a PDMS foam absorption tube at various times during GC analysis. Combinations of GC peaks were trapped on PDMS tubes, desorbed in a Gerstel thermal extractor (off-line), and sniffed. The combination of two analytes was found to cause fishy malodors: heptanal and (E,Z)-3,5-octadien-2-one. Purge-and-trap, solid phase microextraction (SPME), and headspace stir bar sorptive extraction (HSSE) sample preparation methods prior to GC-MS were investigated. All methods confirmed the combination of heptanal and (E,Z)-3,5-octadien-2-one as the cause of fishy odor. © 2014 American Chemical Society. Source

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