Restructuring-induced catalytic activity is an intriguing phenomenon of fundamental importance to rational design of high-performance catalyst materials. We study three copper-complex materials for electrocatalytic carbon dioxide reduction. Among them, the copper(II) phthalocyanine exhibits by far the highest activity for yielding methane with a Faradaic efficiency of 66% and a partial current density of 13 mA cm−2 at the potential of – 1.06 V versus the reversible hydrogen electrode. Utilizing in-situ and operando X-ray absorption spectroscopy, we find that under the working conditions copper(II) phthalocyanine undergoes reversible structural and oxidation state changes to form ~ 2 nm metallic copper clusters, which catalyzes the carbon dioxide-to-methane conversion. Density functional calculations rationalize the restructuring behavior and attribute the reversibility to the strong divalent metal ion–ligand coordination in the copper(II) phthalocyanine molecular structure and the small size of the generated copper clusters under the reaction conditions.
Detrital-zircon geochronology of the northeastern Tibetan plateau Email alerting services cite this article to receive free e-mail alerts when new articles www.gsapubs.org/cgi/alerts click Subscribe America Bulletin to subscribe to Geological Society of www.gsapubs.org/subscriptions/ click Permission request to contact GSA http://www.geosociety.org/pubs/copyrt.htm#gsa click viewpoint. Opinions presented in this publication do not reflect official positions of the Society. positions by scientists worldwide, regardless of their race, citizenship, gender, religion, or political article's full citation. GSA provides this and other forums for the presentation of diverse opinions and articles on their own or their organization's Web site providing the posting includes a reference to the science. This file may not be posted to any Web site, but authors may post the abstracts only of their unlimited copies of items in GSA's journals for noncommercial use in classrooms to further education and to use a single figure, a single table, and/or a brief paragraph of text in subsequent works and to make GSA, employment. Individual scientists are hereby granted permission, without fees or further requests to
[1] The northeastern margin of the Tibetan Plateau is underlain by the Qaidam and Qilian terranes, which consist primarily of mid-Proterozoic through lower Paleozoic oceanic and arc-type assemblages that have been accreted to the southern margin of the Tarim/SinoKorean craton. Most previous models suggest that these assemblages formed along a northeast dipping subduction system constructed along the margin of the Tarim/SinoKorean craton during early Paleozoic time. The main components are interpreted to have formed either as an archipelago of volcanic arcs and back arc basins, or as a broad expanse of accretionary complexes. Our geochronologic data support a model, suggested by Sobel and Arnaud [1999], in which the Qaidam and Qilian terranes are separated from the Tarim/Sino-Korean craton by a mid-Paleozoic suture that closed along a southwest dipping subduction zone. The basement to these terranes consists of oceanic assemblages that were amalgamated into a coherent crustal fragment prior to emplacement of $920-930 Ma granitoids. Early Paleozoic arc-type magmatism occurred between $480 and $425 Ma, apparently sweeping southwestward across much of the Qilian and Qaidam terranes. Accretion-related magmatism along the inboard margin of the Qilian terrane occurred between $423 Ma and $406 Ma. Following Silurian-Devonian accretion, the region has experienced late Paleozoic and Mesozoic uplift and erosion and has been severely overprinted by Tertiary thrusting, uplift, and strike-slip motion along the Altyn Tagh fault. Correlation of geologic features and magmatic histories between the Altun Shan and the Nan Shan suggests that the eastern Altyn Tagh fault has a total left-lateral offset of $375 km.
Introduction The pattern of exhaled breath volatile organic compounds represents a metabolic biosignature with the potential to identify and characterize lung cancer. Breath biosignature-based classification of homogeneous subgroups of lung cancer may be more accurate than a global breath signature. Combining breath biosignatures with clinical risk factors may improve the accuracy of the signature. Objectives Develop an exhaled breath biosignature of lung cancer using a colorimetric sensor array. Determine the accuracy of breath biosignatures of lung cancer characteristics with and without the inclusion of clinical risk factors. Methods The exhaled breath of 229 study subjects, 92 with lung cancer and 137 controls, was drawn across a colorimetric sensor array. Logistic prediction models were developed and statistically validated based on the color changes of the sensor. Age, sex, smoking history, and COPD were incorporated in the prediction models. Results The validated prediction model of the combined breath and clinical biosignature was moderately accurate at distinguishing lung cancer from control subjects (C-statistic 0.811). The accuracy improved when the model focused on only one histology (C-statistic 0.825 – 0.890). Individuals with different histologies could be accurately distinguished from one another (C-statistic 0.889 for adenocarcinoma vs. squamous cell carcinoma). Moderate accuracies were noted for validated breath biosignatures of stage and survival (C-statistic 0.793, 0.770 respectively). Conclusions A colorimetric sensor array is capable of identifying exhaled breath biosignatures of lung cancer. The accuracy of breath biosignatures can be optimized by evaluating specific histologies and incorporating clinical risk factors.
Abstract-Traumatic brain injury (TBI) is a common injury type among Operation Iraqi Freedom/Operation Enduring Freedom (OIF/OEF) veterans, and headaches are a frequent consequence of TBI. We examined the hypothesis that among veterans who reported mild TBI caused by exposure to an explosion during deployment in OIF/OEF, those with residual neurocognitive deficits would have a higher frequency of headaches and more severe headaches. We evaluated 155 consecutive veterans with neurological examination and neuropsychological testing. We excluded 29 veterans because they did not have mild TBI or they did not complete the evaluation. We analyzed headache pattern, intensity, and frequency. Among the 126 veterans studied, 80 had impairments on neurological examination or neuropsychological testing that were best attributed to TBI. Veterans with impairments had been exposed to more explosions and were more likely to have headache, features of migraine, more severe pain, more frequent headaches, posttraumatic stress disorder, and impaired sleep with nightmares.
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