Evaluating the benefit of structural health monitoring for improving bridge resilience against scour. Deliverable D1 – Report on critical review of alternative techniques for bridge scour monitoring

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Cues to opening mechanisms from in silico electric field excitation of cx26 hemichannel and in vitro mutagenesis studies in HeLa transfectans

Connexin channels play numerous essential roles in virtually every organ by mediating solute exchange between adjacent cells, or between cytoplasm and extracellular milieu. Our understanding of the structure-function relationship of connexin channels relies on X-ray crystallographic data for human connexin 26 (hCx26) intercellular gap junction channels. Comparison of experimental data and molecular dynamics simulations suggests that the published structures represent neither fully-open nor closed configurations. To facilitate the search for alternative stable configurations, we developed a coarse grained (CG) molecular model of the hCx26 hemichannel and studied its responses to external electric fields. When challenged by a field of 0.06 V/nm, the hemichannel relaxed toward a novel configuration characterized by a widened pore and an increased bending of the second transmembrane helix (TM2) at the level of the conserved Pro87. A point mutation that inhibited such transition in our simulations impeded hemichannel opening in electrophysiology and dye uptake experiments conducted on HeLa tranfectants. These results suggest that the hCx26 hemichannel uses a global degree of freedom to transit between different configuration states, which may be shared among the whole connexin family

Electromagnetic sensors for underwater scour monitoring

Scour jeopardises the safety of many civil engineering structures with foundations in riverbeds and it is the leading cause for the collapse of bridges worldwide. Current approaches for bridge scour risk management rely mainly on visual inspections, which provide unreliable estimates of scour and of its effects, also considering the difficulties in visually monitoring the riverbed erosion around submerged foundations. Thus, there is a need to introduce systems capable of continuously monitoring the evolution of scour at bridge foundations, even during extreme flood events. This paper illustrates the development and deployment of a scour monitoring system consisting of smart probes equipped with electromagnetic sensors. This is the first application of this type of sensing probes to a real case-study for continuous scour monitoring. Designed to observe changes in the permittivity of the medium around bridge foundations, the sensors allow for detection of scour depths and the assessment of whether the scour hole has been refilled. The monitoring system was installed on the A76 200 Bridge in New Cumnock (S-W Scotland) and has provided a continuous recording of the scour for nearly two years. The scour data registered after a peak flood event (validated against actual measurements of scour during a bridge inspection) show the potential of the technology in providing continuous scour measures, even during extreme flood events, thus avoiding the deployment of divers for underwater examination

Bayesian multi-parameter estimation using the mechanical equivalent of logical inference

In this work we illustrate how the mathematics of rational thinking is formally equivalent to that of structural mechanics. Concepts from the wold of logic, such as accuracy, uncertainty, Maximum a Posteriori (MAP) and rationality correspond, in the world of mechanics, to stiffness, flexibility, equilibrium and conservativeness. For instance, a linear Gaussian N-parameter estimation problem can be solved through a N-dof linear elastic system, as the analogy goes along these lines: the parameters covariance matrix is the system's flexibility matrixthe Fishers information is the stiffness matrixthe negative log-distribution of the parameters is the elastic potential energy of the systemthe Maximum a Posteriori (MAP) is the state of static equilibrium. In principle, based on this analogy, we could reproduce any logical inference problem with a finite element model, and make a judgment by finding its equilibrium state. We will show application of this analogy to a number of civil engineering inference problems, including Bayesian estimation, Bayesian networks and Kalman filter

BLACK STUDENTS IN THE PUBLIC UNIVERSITY: TENSIONS AND CHALLENGES IN HIGHER EDUCATION

Insertado en el contexto de transformación de las universidades brasileñas engendradas por las políticas de acceso y permanencia en la educación superior implementadas en las últimas décadas, el objetivo de este estudio es discutir los significados producidos en la experiencia universitaria por estudiantes de pregrado negros, de escuelas públicas y de movimientos sociales vinculados al campo. La producción de información se realizó a través de ruedas de conversación y de textos escritos por participantes de talleres de lectura y escritura realizados en dos universidades federales brasileñas. Las declaraciones y textos producidos fueron sometidos a un análisis del discurso basado en la perspectiva dialógica de Bakhtin, permitiendo el reconocimiento de los desafíos ideológicos que enfrentan los estudiantes, desafíos que se realizan a través de formas de usar el lenguaje académico, problemas de identidad, enfrentamientos políticos y limitaciones en el currículum. Los resultados también discuten las posibilidades de reflexionar sobre discursos que asumen un carácter monológico en el contexto universitario.Inserido no contexto de transformação das universidades brasileiras engendrado pelas políticas de acesso e permanência no ensino superior implantadas nas últimas décadas, este estudo tem como objetivo discutir os sentidos produzidos sobre a experiência universitária por estudantes de graduação negros, provenientes de escola pública e de movimentos sociais ligados ao campo. A produção de informações ocorreu a partir de rodas de conversa e de textos escritos por estudantes participantes de oficinas de leitura e escrita criativa realizadas em duas universidades federais brasileiras. Os depoimentos e textos produzidos foram submetidos a uma análise de discurso com base na perspectiva dialógica de Bakhtin, possibilitando o reconhecimento dos desafios ideológicos enfrentados pelos/as estudantes, desafios esses que se realizam por meio de modos de uso da linguagem acadêmica, de questões identitárias, de embates políticos e de limitações nas grades curriculares. Os resultados também discutem possibilidades de tensionamento de discursos que assumem caráter monológico no contexto universitário.Inserted in the context of transformation of Brazilian universities engendered by the policies of access and permanence in higher education implemented during the last decades, this study discusses the meanings on the university experience produced by undergraduate black students from public schools and from social movements of rural workers. The information was produced through dialogue circles and through texts written by students who participated of reading and writing workshops held at two Brazilian federal universities. The statements and texts were analyzed through Bakhtin's dialogical perspective, enabling the recognition of the ideological challenges faced by students, such as the use of academic language, identity issues, political clashes and curricular limitations. The results also discuss possibilities of questioning monological discourses that prevail in the university context

Escritos nas paredes: tensões no contexto universitário

O presente artigo tem como objetivo discutir a comunicação escrita em paredes de uma universidade pública federal, comunicação essa que visibiliza as tensões características das relações instituídas nas cidades contemporâneas. As intervenções nesses espaços são abordadas como enunciados em campos discursivos, tal como propõe a filosofia da linguagem de Bakhtin, e articuladas a discussões sobre o processo de espetacularização das cidades, dando-se destaque ao distanciamento entre sujeitos. A análise revela a arena de vozes sociais constituída no cotidiano universitário, sendo as intervenções nas paredes formas de resistência à tentativa institucional de harmonização dos espaços e dos discursos amparada na ordem de conservação do patrimônio público

Tripodal gold(I) polypyridyl complexes and their Cu+ and Zn2+ heterometallic derivatives. Effects on luminescence

Three gold(I) tripodal complexes containing the tris(2-pyridylmethyl)amine (TPA) ligand coordinated to Au-PR3 moieties (PR3 = 1,3,5-triaza-7-phosphatricyclo[3.3.1.13.7]decane, PTA (1), 3,7-diacetyl-1,3,7-triaza-5-phosphabicyclo[3.3.1]nonane, DAPTA (2) and triphenylphosphane (3)) were prepared together with a cage-like structure containing triphosphane 1,1,1-tris(diphenylphosphinomethyl)ethane (4). The luminescence of these complexes has been studied and they show a red shift upon the formation of heterometallic complexes by reaction with Zn(NO3)2, CuCl and [Cu(CH3CN)4]BF4. The different coordination motifs of the Zn2+ and Cu+ heterometallic species and the resulting changes in the recorded absorption, emission and NMR spectra were analysed and supported by TD-DFT calculations

A Human-Derived Monoclonal Antibody Targeting Extracellular Connexin Domain Selectively Modulates Hemichannel Function

Connexin hemichannels, which are plasma membrane hexameric channels (connexons) composed of connexin protein protomers, have been implicated in a host of physiological processes and pathological conditions. A number of single point pathological mutations impart a "leaky" character to the affected hemichannels, i.e., make them more active or hyperactive, suggesting that normal physiological condition could be recovered using selective hemichannel inhibitors. Recently, a human-derived monoclonal antibody named abEC1.1 has been shown to inhibit both wild type and hyperactive hemichannels composed of human (h) connexin 26 (hCx26) subunits. The aims of this work were (1) to characterize further the ability of abEC1.1 to selectively modulate connexin hemichannel function and (2) to assess its in vitro stability in view of future translational applications. In silico analysis of abEC1.1 interaction with the hCx26 hemichannel identified critically important extracellular domain amino acids that are conserved in connexin 30 (hCx30) and connexin 32 (hCx32). Patch clamp experiments performed in HeLa DH cells confirmed the inhibition efficiency of abEC1.1 was comparable for hCx26, hCx30 and hCx32 hemichannels. Of note, even a single amino acid difference in the putative binding region reduced drastically the inhibitory effects of the antibody on all the other tested hemichannels, namely hCx30.2/31.3, hCx30.3, hCx31, hCx31.1, hCx37, hCx43 and hCx45. Plasma membrane channels composed of pannexin 1 were not affected by abEC1.1. Finally, size exclusion chromatography assays showed the antibody does not aggregate appreciably in vitro. Altogether, these results indicate abEC1.1 is a promising tool for further translational studies