57 research outputs found
An analysis of corporate ethical code studies: “Where do we go from here?”
The dramatic increase in the number of corporate ethical codes over the past 20 years has been attributed to the Watergate scandal and the Foreign Corrupt Practices Act. Ethical codes differ somewhat from profesional codes and mission statements; yet the terms are frequently interchanged and often confused in the literature. Ethical code studies are reviewed in terms of how codes are communicated to employees and whether implications for violating codes are discussed. Most studies use content analysis to determine subjects in codes. Little information is available about how codes are communicated, whether they are accepted and used by employees, and whether they affect employee/corporate behavior. More research on ethical codes is needed to answer some of these questions.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42514/1/10551_2004_Article_BF00877156.pd
Direct Analysis of Xanthine Stimulants in Archaeological Vessels by Laser Desorption Resonance Enhanced Multiphoton Ionization
Organizações familiares por uma lntrodução a sua tradição contemporaneidade e muldisciplinaridade
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Evidence for competing proton-transfer and hydrogen-transfer reactions in the S-1 state of indigo
Unravelling the Keto-Enol Tautomer Dependent Photochemistry and Degradation Pathways of the Protonated UVA Filter Avobenzone
Avobenzone (AB) is a widely used UVA filter known to undergo irreversible photodegradation. Here, we investigate the detailed pathways by which AB photodegrades by applying UV laser-interfaced mass spectrometry to protonated AB ions. Gas-phase infrared multiple-photon dissociation (IRMPD) spectra obtained with the free electron laser for infrared experiments, FELIX, (600-1800 cm-1) are also presented to confirm the geometric structures. The UV gas-phase absorption spectrum (2.5-5 eV) of protonated AB contains bands that correspond to selective excitation of either the enol or diketo forms, allowing us to probe the resulting, tautomer-dependent photochemistry. Numerous photofragments (i.e. photodegradants) are directly identified for the first time, with m/z 135 and 161 dominating, and m/z 146 and 177 also appearing prominently. Analysis of the production spectra of these photofragments reveals that that strong enol to keto photoisomerism is occurring, and that protonation significantly disrupts the stability of the enol (UVA active) tautomer. Close comparison of fragment ion yields with the TDDFT-calculated absorption spectra give detailed information on the location and identity of the dissociative excited state surfaces, and thus provide new insight into the photodegradation pathways of avobenzone, and photoisomerisation of the wider class of β-diketone containing molecules.<br /
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Direct Analysis of Xanthine Stimulants in Archaeological Vessels by Laser Desorption Resonance Enhanced Multiphoton Ionization.
Resonance enhanced multiphoton ionization spectroscopy (REMPI) generates simultaneous vibronic spectroscopy and fragment free mass spectrometry to identify molecules within a complex matrix. We combined laser desorption with REMPI spectroscopy to study organic residues within pottery sherds from Maya vessels (600-900 CE) and Mississippian vessels (1100-1200 CE), successfully detecting three molecular markers, caffeine, theobromine, and theophylline, associated with the use of cacao. This analytical approach provides a high molecular specificity, based on both wavelength and mass identification. At the same time, the high detection limit allows for direct laser desorption from sherd scrapings, avoiding the need for extracting organic constituents from the sherd matrix
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