Adsorption and Electrooxidation of Carbon Monoxide on Platinum Surfaces Modified with Sulfur

吸附硫通常被认为是表面化学反应毒物. 然而，少量的硫能够增强铂的一氧化碳（CO）电氧化活性。本文利用常规电化学手段及表面增强拉曼光谱研究了CO在硫修饰的铂表面的电氧化. 对于溶液中的CO，其在硫修饰铂电极上的起始氧化电位最多可以比非修饰电极负移超过300 mV，而且在硫覆盖度低于0.6的条件下电位负移量随覆盖度增加而增大. 这一电催化活性的增强也受溶液pH值的影响. 在低硫覆盖度（小于0.3）下，吸附态的CO电氧化峰值电位比非修饰铂电极负移约40 mV. 然而，在高硫覆盖度下，其峰值电位比非修饰铂电极正移近30 mV. 表面增强拉曼光谱显示共吸附硫使Pt-CO振动频率显著红移. 作者认为这些结果是由于吸附硫弱化Pt-CO键及阻化CO在铂表面的移动引起的.Adsorbed sulfur is commonly considered as a reaction poison. However, small amounts of sulfur on platinum significantly increase the surface reactivity toward carbon monoxide (CO) electrooxidation. For the solution CO oxidation, the onset potential was shifted up to over 300 mV negative to that on S-free surface, and the extent of the negative potential shift increases with the sulfur coverage (Xs) up to about 0.6. The enhanced CO oxidation also depends on the solution pH. For the adsorbed CO, at low sulfur coverages (Xs < 0.3), the oxidation peak potential is about 40 mV negative to that of the corresponding clean Pt. However, at higher coverages, the peak potential is about 30 mV more positive. Surface-enhanced Raman spectra show that the adsorption of sulfur significantly redshifts the Pt-CO stretching frequency. These observations are explained by the weakening of the Pt-CO bond and the hindrance of CO diffusion by Sads.This work was supported by Miami University startup fundsThis work was supported by Miami University startup funds作者联系地址：迈阿密大学牛津分校化学&生物化学系，美国 俄亥俄州 45056，Author's Address: Department of Chemistry & Biochemistry, Miami University, Oxford, OH 45056, USA通讯作者E-mail：[email protected]

Effusive and explosive volcanism on the ultraslow-spreading Gakkel Ridge, 85°E

Author Posting. © American Geophysical Union, 2012. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geochemistry Geophysics Geosystems 13 (2012): Q10005, doi:10.1029/2012GC004187.We use high-definition seafloor digital imagery and multibeam bathymetric data acquired during the 2007 Arctic Gakkel Vents Expedition (AGAVE) to evaluate the volcanic characteristics of the 85°E segment of the ultraslow spreading Gakkel Ridge (9 mm yr−1 full rate). Our seafloor imagery reveals that the axial valley is covered by numerous, small-volume (order ~1000 m3) lava flows displaying a range of ages and morphologies as well as unconsolidated volcaniclastic deposits with thicknesses up to 10 cm. The valley floor contains two prominent volcanic lineaments made up of axis-parallel ridges and small, cratered volcanic cones. The lava flows appear to have erupted from a number of distinct source vents within the ~12–15 km-wide axial valley. Only a few of these flows are fresh enough to have potentially erupted during the 1999 seismic swarm at this site, and these are associated with the Oden and Loke volcanic cones. We model the widespread volcaniclastic deposits we observed on the seafloor as having been generated by the explosive discharge of CO2 that accumulated in (possibly deep) crustal melt reservoirs. The energy released during explosive discharge, combined with the buoyant rise of hot fluid, lofted fragmented clasts of rapidly cooling magma into the water column, and they subsequently settled onto the seafloor as fall deposits surrounding the source vent.We gratefully acknowledge the financial support of the National Aeronautics and Space Administration, the National Science Foundation (N.S.F.), the International Polar Year 2007–2008, and Woods Hole Oceanographic Institution; and the graduate support provided by N.S.F., the NDSEG Fellowship, and WHOI Deep Ocean Exploration Institute.2013-04-0

Exploiting RAS Nucleotide Cycling as a Strategy for Drugging RAS-Driven Cancers

Oncogenic mutations in RAS genes result in the elevation of cellular active RAS protein levels and increased signal propagation through downstream pathways that drive tumor cell proliferation and survival. These gain-of-function mutations drive over 30% of all human cancers, presenting promising therapeutic potential for RAS inhibitors. However, many have deemed RAS “undruggable” after nearly 40 years of failed drug discovery campaigns aimed at identifying a RAS inhibitor with clinical activity. Here we review RAS nucleotide cycling and the opportunities that RAS biochemistry presents for developing novel RAS inhibitory compounds. Additionally, compounds that have been identified to inhibit RAS by exploiting various aspects of RAS biology and biochemistry will be covered. Our current understanding of the biochemical properties of RAS, along with reports of direct-binding inhibitors, both provide insight on viable strategies for the discovery of novel clinical candidates with RAS inhibitory activity

Postoperative Complications After Interpolated Flap Repair for Mohs Defects of the Nose: A Multicenter Prospective Cohort Study

BACKGROUND: Dermatologists perform most interpolated flaps after skin cancer resection. Prospective, multicenter data on complications after interpolated flap repair in this setting are limited. OBJECTIVE: To determine the rate of physician-reported complications after interpolated flap repair of the nose. METHODS: Multicenter, prospective cohort study of 169 patients undergoing 2-stage interpolated flap repair of post-Mohs nasal defects. Frequency of bleeding, infection, dehiscence, necrosis, hospitalization, and death in the 30 days after flap placement and flap takedown are reported. RESULTS: Patients experienced 23 complications after flap placement (13.61%) and 6 complications after flap takedown (3.55%) that were related to the surgical procedure. The most frequent complication after flap placement was bleeding (9, 5.33%, 95% confidence interval [CI]: 2.83%-9.82%). The most frequent complication after flap takedown was infection (5, 2.96%, 95% CI: 1.27%-6.74%). There was one hospitalization related to an adverse reaction to antibiotics. There were no deaths. CONCLUSION: Most complications after interpolated flap repair for post-Mohs defects of the nose are minor and are associated with flap placement. Interpolated flap repair for post-Mohs defects can be performed safely in the outpatient setting under local anesthesia

Patient-Reported Nasal Function and Appearance After Interpolation Flap Repair Following Skin Cancer Resection: A Multicenter Prospective Cohort Study

Among patients undergoing two-stage interpolated flap repair of nasal defects, nasal function, and appearance before surgery and at 16 weeks after flap takedown were compared using the Nasal Appearance and Function Evaluation Questionnaire (NAFEQ). Multicenter prospective cohort study. Adult patients with a nasal skin cancer anticipated to require two-stage interpolation flap repair completed the NAFEQ before surgery, at 1 week after flap placement, 4 weeks after flap takedown, and 16 weeks after flap takedown. One hundred sixty-nine patients were enrolled, with 138 patients completing both presurgical and 16-week post-takedown NAFEQs. Overall NAFEQ score increased by 1.09 points (1.91% improvement, confidence interval [95% CI -0.34 to 2.53]). NAFEQ functional subscale increased by 0.72 points (2.58% increase; 95% CI [0.10-1.35]) and appearance subscale increased by 0.37 points (1.28% improvement, 95% CI [-0.65 to 1.39]). At 16 weeks after flap takedown, patients\u27 perceptions of their nasal function and appearance are similar to or slightly improved when compared with their presurgical assessments

Core Outcome Set for Actinic Keratosis Clinical Trials

Question What are the most important outcomes to report in clinical trials on actinic keratosis? Findings In this survey study including physician and patient stakeholders (33 in round 1 and 29 in round 2), a consensus was reached regarding a core set of 6 of 137 outcomes and domains of actinic keratosis: complete clearance of actinic keratoses, percentage of actinic keratoses cleared, severity of adverse events, patient perspective on effectiveness, patient-reported future treatment preference, and rate of recurrence. Meaning In studies of treatment of actinic keratosis, the recommended core outcomes should be reported as a minimum to facilitate comparison of results across studies. This survey study assesses the most important outcomes to report in clinical trials on actinic keratosis based on Delphi surveys completed by physician and patient stakeholders. Importance Although various treatments have been found in clinical trials to be effective in treating actinic keratosis (AK), researchers often report different outcomes. Heterogeneous outcome reporting precludes the comparison of results across studies and impedes the synthesis of treatment effectiveness in systematic reviews. Objective To establish an international core outcome set for all clinical studies on AK treatment using systematic literature review and a Delphi consensus process. Evidence Review Survey study with a formal consensus process. The keywords actinic keratosis and treatment were searched in PubMed, Embase, CINAHL, and the Cochrane Library to identify English-language studies investigating AK treatments published between January 1, 1980, and July 13, 2015. Physician and patient stakeholders were nominated to participate in Delphi surveys by the Measurement of Priority Outcome Variables in Dermatologic Surgery Steering Committee members. All participants from the first round were invited to participate in the second round. Outcomes reported in randomized controlled clinical trials on AK treatment were rated via web-based e-Delphi consensus surveys. Stakeholders were asked to assess the relative importance of each outcome in 2 Delphi survey rounds. Outcomes were provisionally included, pending the final consensus conference, if at least 70% of patient or physician stakeholders rated the outcome as critically important in 1 or both Delphi rounds and the outcome received a mean score of 7.5 from either stakeholder group. Data analysis was performed from November 5, 2018, to February 27, 2019. Findings A total of 516 outcomes were identified by reviewing the literature and surveying key stakeholder groups. After deduplication and combination of similar outcomes, 137 of the 516 outcomes were included in the Delphi surveys. Twenty-one physicians and 12 patients participated in round 1 of the eDelphi survey, with 17 physicians (81%) retained and 12 patients (100%) retained in round 2. Of the 137 candidate outcomes, 9 met a priori Delphi consensus criteria, and 6 were included in the final outcomes set after a consensus meeting: complete clearance of AKs, percentage of AKs cleared, severity of adverse events, patient perspective on effectiveness, patient-reported future treatment preference, and recurrence rate. It was recommended that treatment response be assessed at 2 to 4 months and recurrence at 6 to 12 months, with the AK rate of progression to cutaneous squamous cell carcinoma reported whenever long-term follow-up was possible. Conclusions and Relevance Consensus was reached regarding a core outcome set for AK trials. Further research may help determine the specific outcome measures used to assess each of these outcomes.12 month embargo; published online: 15 January 2020This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]