The Ritter reaction of 1,2-diolmonoesters with nitriles to 1- vic-amido-2-esters proceeds through dioxonium and nitrilium cation intermediates. To provide the basis for the reaction mechanism, novel forms of these cations were isolated, characterized, and studied by spectroscopic methods and single crystal X-ray analysis. Ground and transition state energies were determined both experimentally and theoretically.
View Article and Find Full Text PDFACS Appl Mater Interfaces
April 2017
Organic light-emitting diode (OLED) displays have been an active and intense area of research for well over a decade and have now reached commercial success for displays from cell phones to large format televisions. A more thorough understanding of the many different potential degradation modes which cause OLED device failure will be necessary to develop the next generation of OLED materials, improve device lifetime, and to ultimately improve the cost vs performance ratio. Each of the different organic layers in an OLED device can be susceptible to unique decomposition pathways, however stability toward excitons is critical for emissive layer (EML) materials as well as any layer near the recombination zone.
View Article and Find Full Text PDFAn ion of m/z 110.06036 (ion formula [C6H8NO](+); error: 0.32 mDa) was observed in the collision induced dissociation tandem mass spectrometry experiments of protonated N-(3-aminophenyl)benzamide, which is a rearrangement product ion purportedly through nitrogen-oxygen (N-O) exchange.
View Article and Find Full Text PDFElectrospray ionization (ESI) of solution mixtures often generates complex mass spectra, even following liquid chromatography (LC), due to analyte multiple charging. Multiple charge state distributions can lead to isobaric interferences, mass spectral congestion, and ambiguous ion identification. As a consequence, data interpretation increases in complexity.
View Article and Find Full Text PDFProc (Bayl Univ Med Cent)
January 2016
Kaposi sarcoma is a neoplasm commonly associated with human herpesvirus 8 and HIV/AIDS. We present a 44-year-old African immigrant woman who presented to the emergency department after several months of abdominal pain. She was found to be HIV positive, and computed tomography demonstrated numerous lesions of the lungs, liver, and spleen, gastric wall thickening, and several lytic lesions of the spine.
View Article and Find Full Text PDFProc (Bayl Univ Med Cent)
January 2016
Cavernous sinus thrombosis is a rare, potentially fatal cause of cerebral venous thrombosis. Infectious causes typically arise from the mid face, orbit, or sinonasal region. We present a case of bilateral cavernous sinus and superior ophthalmic thrombosis secondary to an extreme case of facial cellulitis.
View Article and Find Full Text PDFWhen performed for Budd-Chiari syndrome (BCS), transjugular intrahepatic portosystemic shunt (TIPS) creation can be technically difficult due to hepatic congestion and asymmetric hypertrophy. We present three female patients with decompensated BCS in whom TIPS were created using a three-dimensional fluoroscopy guidance system. On a dedicated workstation using three-dimensional volumes of computed tomography imaging, a virtual needle path was created by the operator extending from the needle entry point (hepatic vein stump or inferior vena cava) to the target portal vein.
View Article and Find Full Text PDFA derivatization procedure has been developed for the improved characterization of fatty alcohol ethoxylate non-ionic surfactants by liquid chromatography/mass spectrometry. The end hydroxyl group of each surfactant species was converted into an oxycarbonylbenzene-2-sulfonic acid group with 2-sulfobenzoic anhydride under mild conditions. The produced sulfonic acid group allows all species, including fatty alcohols and those with less than three ethoxylates, to be uniformly ionized by electrospray ionization (ESI) mass spectrometry.
View Article and Find Full Text PDFA comprehensive multidimensional liquid chromatography system coupled to Electrospray Ionization-Mass Spectrometry (LCxLC-ESI-MS) was developed for detailed characterization and quantitation of solid epoxy resin components. The two orthogonal modes of separation selected were size exclusion chromatography (SEC) in the first dimension and liquid chromatography at critical conditions (LCCC) in the second dimension. Different components present in the solid epoxy resins were separated and quantitated for the first time based on the functional groups and molecular weight heterogeneity.
View Article and Find Full Text PDFA headspace gas chromatographic method has been developed for analysis of aliphatic amines in oligonucleotides. The linearity was improved by including ammonia in the sample vials. Also, carryover of longer chain primary amines, hexylamine and octylamine, was substantially reduced by cleaning the injection syringe with ammonia and water vapor between sample injections.
View Article and Find Full Text PDFThe Sample Survey of Military Personnel in Spring 1996 included detailed questions specifically about soldiers' professional values, centered on personal beliefs about loyalty and integrity values. Maximum likelihood factor analysis yielded four factors, labeled military dedication, integrity, job commitment, and military bearing. Scales developed from these factors showed acceptable internal consistency reliability and correlated as expected with measures of satisfaction with Army life, retention, soldier morale, combat preparedness, and overall job satisfaction.
View Article and Find Full Text PDFThe Sample Survey of Military Personnel in the spring of 1996 asked detailed questions of Army personnel about job satisfaction. Maximum likelihood factor analysis yielded four factors: satisfaction with supervision, with job environment, with the duty specifically, and with opportunity for development, factors similar to those used in Smith's Job Descriptive Index, 1992. Scales developed from these factors showed acceptable internal consistency reliability and correlated as expected with measures of satisfaction with Army life, retention, morale, combat preparedness, and overall job satisfaction.
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