2,274 research outputs found
Insight into Solvent Coordination of an Iron Porphyrin Hydroxylamine Complex from Spectroscopy and DFT Calculations
The reduction of Fe(OEP)(NO) in the presence of substituted phenols leads to a threeâelectron reduction to form Fe(OEP)(NH2OH), which has been characterized by visible spectroscopy and electron stoichiometry. In this work, we have further characterized this species using infrared and 1H NMR spectroscopy, along with DFT calculations. The infrared bands in the 3400â3600 cmâ1 region, due to hydroxylamine, were significantly downshifted to the 2500â2700 cmâ1 region when 4â[D1]chlorophenol replaced the normal abundance acid. Using 1H NMR spectroscopy, the hydroxylamine and the mesoâprotons were identified. From DFT calculations, the 1H NMR spectra were most consistent with a sixâcoordinate complex, Fe(OEP)(NH2OH)(THF)
Redox and Spectroscopic Properties of Iron Porphyrin Nitroxyl in the Presence of Weak Acids
The spectroelectrochemistry and voltammetry of Fe(OEP) (NO) in the presence of substituted phenols was studied. Cyclic voltammetry showed that two closely spaced waves were observed for the reduction of Fe(OEP) (NO) in the presence of substituted phenols. The first wave was a single electron reduction under voltammetric conditions. The second wave was kinetically controlled, multielectron process. Visible spectroelectrochemistry of Fe(OEP) (NO) in the presence of substituted phenols showed that three species were present during the electrolysis. Additional spectroscopic studies indicated that the two reduction species were Fe(OEP) (HNO) and Fe(OEP)(H2NOH). The Fe(OEP) (HNO) species, which can be generated chemically, was stable over a period of hours. Additional acid did not lead to further protonation. Proton NMR spectroscopy confirmed the Fe(OEP) (HNO) species could be deprotonated under basic conditions. The third species, Fe(OEP)(H2NOH), was generated by the further reduction of the chemically generated Fe(OEP) (HNO) complex. Both the Fe(OEP) (HNO) and Fe(OEP)(H2NOH) complexes could be slowly oxidized back to Fe(OEP) (NO). At millimolar concentrations of Fe(OEP) (HNO), there was no evidence for the disproportionation of Fe(OEP) (HNO) to Fe(OEP) (NO) and H2 in the presence of substituted phenols. Nor was there evidence for the generation of N2O. The FTIR spectroelectrochemistry showed changes in the infrared spectra in the presence of substituted phenols, but no isotopic sensitive bands were observed for the reduced species between 1450 and 1200 cmâ1. This may be because the νNO band shifted into a region (1500â1450 cmâ1) where it would be difficult to observe
Catalytic Reduction of Bisulfite by Myoglobin/Surfactant Films
The voltammetry of bisulfite at a film formed with myoglobin was studied in aqueous solutions. A broad wave was observed for the reduction of bisulfite. Using controlled potential electrolysis, the reduction at potentials positive of the FeII/FeIwave formed dithionite exclusively. As the potential approached the region for the FeII/FeI reduction, bisulfite was reduced primarily to HSâ. Even at the negative potentials, some dithionite was still formed, which could then be electrochemically reduced to thiosulfate. Analysis of the formation of HSâ, dithionite and thiosulfate during the electrolysis was consistent with the parallel formation of HSâand dithionite, the latter of which was reduced to thiosulfate. Thiosulfate was verified by chemical analysis of the products from controlled potential electrolysis of the solution, and dithionite was observed spectroscopically using spectroelectroâchemistry
Assessing regional digital competence: Digital futures and strategic planning implications
Understanding strategic decisions aimed at addressing regional economic issues is of increasing interest among scholars and policy makers today. Thus, studies that proffer effective strategies to address digital futures concerns from social and policy perspectives are timely. In light of this, this research uses strengths, weaknesses, opportunities and threats (SWOT) analysis tool to frame a regional strategy for digital futures to enhance place-specific digital connectivity and socio-economic progress. Focus group discussions and a structured questionnaire were conducted to examine a SWOT for a digital economy strategy in the Southern Downs Region in Queensland, Australia. The findings show that while the proposed regional strategies for digital futures are susceptible to internal and external forces, strategic planning makes them manageable. The studyâs findings also reveal that adaptive strategic planning can help regulate the effects of internal and external factors that shape individual and organisational responses to digital transformation, and that these factors promote regional competitiveness
X-ray Structure and Properties of the Ferrous Octaethylporphyrin Nitroxyl Complex
The preparation and characterization of the iron octaethylporphyrin nitroxyl ion, [Fe(OEP)(NO)â], is reported. The complex was synthesized by the one-electron reduction of Fe(OEP)(NO) using anthracenide as the reducing agent. The compound was isolated as the potassium (2.2.2)cryptand salt. The anion was characterized using X-ray analysis with visible and infrared spectroscopy. The spectral features of the iron nitroxyl complex were consistent with previous literature reports. The important structural changes upon reduction were a significant decrease in the FeâNâO bond angle from 142° to 127° and an increase in the NâO bond length from that in the starting nitrosyl moiety. The porphyrin ring became significantly less planar upon reduction, but the displacement of the iron atom from the 24-atom plane was essentially unchanged. In spite of the attempt to encapsulate the potassium ion with the (2.2.2)cryptand, significant interaction between K+ and the oxygen of the nitroxyl were observed, indicating a contact ion pair in the crystal structure. Comparison between the experimental structure and the DFT-calculated parameters were reported. The results are consistent with the FeâNâO moiety being the site of the reduction, with little evidence for the reduction of the iron itself or the porphyrin ring. The proton NMR spectrum was also obtained, and the chemical shifts were significantly different from other S = 0 metalloporphyrin complexes. These shifts, though, were consistent with the DFT calculations
Minimal Access Expandable Mesh Device for Transforaminal Lumbar Interbody Fusion: A Case Series
Bone-sparing techniques for transforaminal lumbar interbody fusion (TLIF) are promoted to help maintain spinal stability and to minimize operative time. We present a series of seven patients who underwent TLIF with use of an interbody expandable mesh device and with supplemental instrumentation. This device is deployed and filled with bone through a small cannula. All patients experienced pain relief and suffered no complications. Our results support the data from other centers which have performed similar procedures with this device
A Review of COVID-19 Modelling Strategies in Three Countries to Develop a Research Framework for Regional Areas
At the end of December 2019, an outbreak of COVID-19 occurred in Wuhan city, China. Modelling plays a crucial role in developing a strategy to prevent a disease outbreak from spreading around the globe. Models have contributed to the perspicacity of epidemiological variations between and within nations and the planning of desired control strategies. In this paper, a literature review was conducted to summarise knowledge about COVID-19 disease modelling in three countries-China, the UK and Australia-to develop a robust research framework for the regional areas that are urban and rural health districts of New South Wales, Australia. In different aspects of modelling, summarising disease and intervention strategies can help policymakers control the outbreak of COVID-19 and may motivate modelling disease-related research at a finer level of regional geospatial scales in the future
Experience of Resident Assistant Does Not Influence Incidence of Common Bile Duct Injuries During Laparoscopic Cholecystectomy
Too Smart to Fail: Guide for the Struggling Medical Student
Medicine is a vocation of perpetual independent learning; long-term success is critically dependent on finding the right resources and establishing effective study methods and test-taking strategies. Students who struggle with the academic transition in medical school have common risk factors and characteristics. We highlight key resources that are available for struggling medical students with an emphasis on West Virginia\u27s HELP, ASPIRE, and STAT programs
Moving beyond misuse and diversion: the urgent need to consider the role of iatrogenic addiction in the current opioid epidemic.
An epidemic of drug overdose deaths has led to calls for programs and policies to limit misuse and diversion of opioid medications. Any parallel call to consider the risk of iatrogenic addiction when treating pain has been muted in comparison. We have moved beyond questions of nonmedical use, abuse, and diversion to highlight the role of prescription opioids in causing addiction even when prescribed and used appropriately. Unfortunately, current evidence is insufficient, and a rapid expansion of longitudinal research is urgently needed to guide clinicians in balancing the need for opioids with the risk of adverse consequences. Meanwhile, medical education should place greater emphasis on the abuse liability of prescription opioids, and providers should endeavor to attenuate risk when possible
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