Multihole water oxidation catalysis on haematite photoanodes revealed by operando spectroelectrochemistry and DFT

Water oxidation is the key kinetic bottleneck of photoelectrochemical devices for fuel synthesis. Despite advances in the identification of intermediates, elucidating the catalytic mechanism of this multi redox reaction on metal oxide photoanodes remains a significant experimental and theoretical challenge. Here, we report an experimental analysis of water oxidation kinetics on four widely studied metal oxides, focusing particularly on haematite. We observe that haematite is able to access a reaction mechanism that is third order in surface hole density, which is assigned to equilibration between three surface holes and M OH O M OH sites. This reaction exhibits low activation energy Ea amp; 8201; amp; 8776; amp; 8201;60 amp; 8201;meV . Density functional theory is used to determine the energetics of charge accumulation and O O bond formation on a model haematite 110 surface. The proposed mechanism shows parallels with the function of the oxygen evolving complex of photosystem II, and provides new insights into the mechanism of heterogeneous water oxidation on a metal oxide surfac

Identification of clonal hematopoiesis mutations in solid tumor patients undergoing unpaired next-generation sequencing assays

Purpose: In this era of precision-based medicine, for optimal patient care, results reported from commercial next-generation sequencing (NGS) assays should adequately reflect the burden of somatic mutations in the tumor being sequenced. Here, we sought to determine the prevalence of clonal hematopoiesis leading to possible misattribution of tumor mutation calls on unpaired Foundation Medicine NGS assays. Experimental Design: This was a retrospective cohort study of individuals undergoing NGS of solid tumors from two large cancer centers. We identified and quantified mutations in genes known to be frequently altered in clonal hematopoiesis (DNMT3A, TET2, ASXL1, TP53, ATM, CHEK2, SF3B1, CBL, JAK2) that were returned to physicians on clinical Foundation Medicine reports. For a subset of patients, we explored the frequency of true clonal hematopoiesis by comparing mutations on Foundation Medicine reports with matched blood sequencing. Results: Mutations in genes that are frequently altered in clonal hematopoiesis were identified in 65% (1,139/1,757) of patients undergoing NGS. When excluding TP53, which is often mutated in solid tumors, these events were still seen in 35% (619/1,757) of patients. Utilizing paired blood specimens, we were able to confirm that 8% (18/226) of mutations reported in these genes were true clonal hematopoiesis events. The majority of DNMT3A mutations (64%, 7/11) and minority of TP53 mutations (4%, 2/50) were clonal hematopoiesis. Conclusions: Clonal hematopoiesis mutations are commonly reported on unpaired NGS testing. It is important to recognize clonal hematopoiesis as a possible cause of misattribution of mutation origin when applying NGS findings to a patient's care

Bootstrap and Nonparametric Predictors to Impute Missing Data

A new nonparametric technique to impute missing data is proposed in order to obtain a completed data-matrix, capable of producing a degree of reliability for the imputations. Without taking into account strong assumptions, we introduce multiple imputations using bootstrap and nonparametric predictors. It is shown that, in this manner, we can obtain better imputations than with other known methods producing a more reliable completed data-matrix. Using two simulations, we show that the proposed technique can be generalized to consider non-monotone patterns of missing data with interesting results

El CoLaboratorio de la Oceanografía Social: Espacio Plural para la Conservación Integral de los Mares y las Sociedades Costera

Este ensayo revisa los alcances de la oceanografía social tal como fue presentada y discutida en la Primera Reunión de Oceanografía Social organizada en el Centro de Estudios en Geografía Humana de El Colegio de Michoacán en septiembre de 2017. La oceanografía social es un campo innovador e híbrido de estudio, situado en el umbral entre las ciencias naturales y sociales que abarca el estudio de las relaciones e interacciones de las sociedades humanas, presentes y pasadas, con el ambiente costero/marino. Dividimos el ensayo en dos secciones. Primero, describimos crono-lógicamente el surgimiento y evolución de la disciplina, así como un panorama contemporáneo del quehacer del oceanógrafo social y la imperante necesidad de expandir esta aproximación a todas las esferas de los estudios marinos. Finalmente, ofrecemos una síntesis de las fortalezas y retos que ofrece la oceanografía social y de cómo nos proponemos enfrentarlos a partir de la formación de un CoLaboratorio. Abstract This essay reviews the scope and aims of Social Oceanography as presented and discussed at the First Social Oceanography Meeting held at the Center for Human Geography Studies of El Colegio de Michoacán in September 2017. Social Oceanography is a hybrid field of study at the interface between the natural and social sciences focused on understanding the relationships and interactions of past and present human societies, and the coastal/marine environment. We present our argument in three sections. First, we describe the chronological development and evolution of the discipline. Second, we offer a contemporary overview of the sphere of action of social oceanogra-phers and the pressing need to extend this approach to all spheres of marine studies. Lastly, we summarize the strengths and challenges of Social Oceanography and the ways we will deal with them through the creation of a CoLaboratory