634 research outputs found
Trial and Scour; Scour and Bed Protection at the Discharge Sluices in the Afsluitdijk, The Netherlands
In Situ ATR-SEIRAS of Carbon Dioxide Reduction at a Plasmonic Silver Cathode.
Illumination of a voltage-biased plasmonic Ag cathode during CO2 reduction results in a suppression of the H2 evolution reaction while enhancing CO2 reduction. This effect has been shown to be photonic rather than thermal, but the exact plasmonic mechanism is unknown. Here, we conduct an in situ ATR-SEIRAS (attenuated total reflectance-surface-enhanced infrared absorption spectroscopy) study of a sputtered thin film Ag cathode on a Ge ATR crystal in CO2-saturated 0.1 M KHCO3 over a range of potentials under both dark and illuminated (365 nm, 125 mW cm-2) conditions to elucidate the nature of this plasmonic enhancement. We find that the onset potential of CO2 reduction to adsorbed CO on the Ag surface is -0.25 VRHE and is identical in the light and the dark. As the production of gaseous CO is detected in the light near this onset potential but is not observed in the dark until -0.5 VRHE, we conclude that the light must be assisting the desorption of CO from the surface. Furthermore, the HCO3- wavenumber and peak area increase immediately upon illumination, precluding a thermal effect. We propose that the enhanced local electric field that results from the localized surface plasmon resonance (LSPR) is strengthening the HCO3- bond, further increasing the local pH. This would account for the decrease in H2 formation and increase the CO2 reduction products in the light
Selective and efficient electrochemical CO2 reduction on nanostructured catalysts
This thesis is part of NanoNextNL, a micro and nanotechnology innovation consortium of the Government of the Netherlands and 130 partners from academia and industry. More information on www.nanonextnl.nl.UBL - phd migration 201
CO_2 Reduction Selective for C_(≥2) Products on Polycrystalline Copper with N-Substituted Pyridinium Additives
Electrocatalytic CO_2 reduction to generate multicarbon products is of interest for applications in artificial photosynthetic schemes. This is a particularly attractive goal for CO_2 reduction by copper electrodes, where a broad range of hydrocarbon products can be generated but where selectivity for C–C coupled products relative to CH_4 and H_2 remains an impediment. Herein we report a simple yet highly selective catalytic system for CO_2 reduction to C_(≥2) hydrocarbons on a polycrystalline Cu electrode in bicarbonate aqueous solution that uses N-substituted pyridinium additives. Selectivities of 70–80% for C_2 and C_3 products with a hydrocarbon ratio of C_(≥2)/CH4significantly greater than 100 have been observed with several additives. ^(13)C-labeling studies verify CO_2 to be the sole carbon source in the C_(≥2) hydrocarbons produced. Upon electroreduction, the N-substituted pyridinium additives lead to film deposition on the Cu electrode, identified in one case as the reductive coupling product of N-arylpyridinium. Product selectivity can also be tuned from C_(≥2) species to H_2 (∼90%) while suppressing methane with certain N-heterocyclic additives
Common Idiopathic Mononeuropathies of the Upper Extremity
This thesis focuses on conditions where a nerve is affected (neuropathy) by compression in the wrist or elbow. For most of these conditions, the cause is unknown (idiopathic). The two most common conditions in the arm are median nerve neuropathy at the carpal tunnel (MNCT) and ulnar nerve neuropathy at the elbow (UNE). The overarching term for the symptoms and signs of these conditions are carpal tunnel syndrome (CTS) and cubital tunnel syndrome, respectively. This thesis is divided in 4 parts. In part 1, multiple patient-reported outcome measures (PROMs) were examined to quantify subjective aspects of health. Strong correlations between PROMs, pain intensity, and quality of life were demonstrated, with psychosocial factors seeming to play a significant role. Part 2 focuses on electrodiagnostics (nerve conduction studies) as a diagnostic tool for MNCT and UNE. The results of the studies suggest diagnostic uncertainty in distinguishing between no and mild neuropathology, indicating a need for improved diagnostic criteria. The third part highlights that patients prefer to share decisions with their surgeon (shared decision-making) in the treatment of CTS. Additionally, a lack of personal financial responsibility was found to be the most common reason for choosing the (more expensive) treatment option; surgery. The final part shows geographical variation in the use of radiographs and corticosteroid injections for CTS and UNE. Finally, patients had less regret about their treatment choice when they had read a decision aid about their condition
Factors associated with patient rating of physician communication effectiveness and satisfaction in musculoskeletal care
Effective communication is associated with adherence to healthy habits. This study sought factors associated with communication effectiveness and satisfaction with musculoskeletal specialty care in order to inform efforts to improve communication effectiveness using measurement, feedback, and coaching. After a new or return upper extremity specialist visit, 146 adult patients completed a survey recording demographics, measures of catastrophic thinking in response to nociception, symptoms of depression, and symptoms of anxiety, and they rated communication effectiveness (5 questions answered on a 4-point Likert scale) and satisfaction with the visit (slider with anchors of 0 and 100). Patients also provided text answers to 4 questions addressing strengths and opportunities for improved communication. We assessed the association of experience measures (communication and overall satisfaction) with patient characteristics. Ratings of “clinician listens carefully” were higher in older patients. Higher rating of clinician explains in an understandable way was associated with fewer symptoms of depression. Higher rating of clinician showed respect was associated with fewer symptoms of depression and less catastrophic thinking. Higher rating of clinician used models was associated with older age. Men had higher overall satisfaction scores. In Factor analysis, the scree plot of eigenvalues showed that the 5 communication questions and the single satisfaction question load onto a single factor. The finding that age and psychological factors are associated with patient experience – which seems to reduce statistically to a single underlying construct – emphasizes a potential to attend to mental health in efforts to improve patient experience.
Experience Framework
This article is associated with the Policy & Measurement lens of The Beryl Institute Experience Framework. (http://bit.ly/ExperienceFramework) Access other PXJ articles related to this lens. Access other resources related to this lens
Ectopic Bone in the Lungs and Spleen of Male Fisher-344 Rats
Previous experimental data demonstrated ossified particles (OSP, i.e., bone-like particles) in the circulation of rodents as well as human subjects. Their ability to circulate could ultimately permit access to vital tissues, potentially leading to ectopic bone formation. Although the fate of OSP is yet unclear, their entry into soft tissues and organs may initiate pathological processes. PURPOSE: We sought to determine the presence of bone in the soft organs. METHODS: Young (6-mon; n=10) and old (24-mon; n=10) male Fisher-344 rats were anesthetized (3% isoflurane to oxygen balance) and euthanized by removal of the heart. Body mass (g) was determined prior to dissecting the right and left lungs and spleen. The tissues were stored in 10% formalin for 3 days at 4°C and then in 70% EtOH at -20°C until analysis. They were subsequently scanned (55 kVp and 145 µA) at 15µm via micro-computed tomography (µCT 45; Scanco Medical, Inc. Switzerland). To determine bone volume within the tissues, the entire lungs and spleen were analyzed. One-Way ANOVAs were used to determine significant differences in body mass (g), right lung mass (g), left lung mass (g), spleen mass (g), bone volume in the right lung (µm3), bone volume in the left lung (µm3), bone volume in the spleen (µm3), bone volume relative to right lung mass (µm3/g), bone volume relative to left lung mass (µm3/g), and bone volume relative to spleen mass (µm3/g). A p value of 0.05 was set a priori. Data are presented as Means ± Standard Deviation. RESULTS: Body mass was higher (pp3 vs. 34.8± 21.6 μm3, respectively) and left (71.2 ± 54.7 μm3 vs. 21.0 ± 7.4 μm3, respectively) lungs were higher (p3 vs. 2.6 ± 4.2 μm3, respectively) did not differ between young and old rats. When normalized to right lung mass (young, 49.2 ± 32.5 μm3/g vs. old, 186.6 ± 117.8 μm3 /g) and left lung mass (young, 42.2 ± 17.5 μm3/g vs. old, 127.0 ± 92.2 μm3/g), bone volumes were higher (p3/g vs. old, 2.3. ± 5.5 μm3/g), no differences were observed. CONCLUSION: We speculate that the presence of bone in the soft organs (i.e., ectopic bone formation) is associated with OSP in the circulation. Ectopic bone formation was exacerbated in the right and left lungs with advancing age. The presence of bone in the soft organs may contribute to a diverse number of pathologies
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