Regular poly(para-phenylene) films bound to gold surfaces through the electrochemical reduction of diazonium salts followed by electropolymerization in an ionic liquid

International audienceBy combining the electroreduction of diazonium salts and the electropolymerization of conducting polymers in an ionic liquid, the electrografting of a regular poly(para-phenylene) film on a gold substrate is achieved, leading to the strong and robust anchoring of the PPP polymers on the substrate (Au-PPP hybrid). A thin layer covalently bound to the substrate is first prepared by the reduction of benzenediazonium salt (BD), then, on top of this layer, a thicker layer of poly(para-phenylene) (PPP) is easily grown by the electrochemical oxidation of biphenyl in the [BMIm][PF6] ionic liquid. The resulting material is thoroughly characterized by IR, ToF-SIMS and fluorescence spectroscopies. The analyses show the formation of well regular PPP layers that are wired to the substrate. The key role of the [BMIm][PF6] ionic liquid in the structuration of the polymer is emphasized

STEM analysis of deformation and B distribution in nanosecond laser ultra-doped Si1−x_{1-x} Bx_x

We report on the structural properties of highly B-doped silicon (> 2 at. %) realised by nanosecond laser doping. We investigate the crystalline quality, deformation and B distribution profile of the doped layer by STEM analysis followed by HAADF contrast studies and GPA, and compare the results to SIMS analyses and Hall measurements. When increasing the active B concentration above 4.3 at.%, the fully strained, perfectly crystalline, Si:B layer starts showing dislocations and stacking faults. These only disappear around 8 at.% when the Si:B layer is well accommodated to the substrate. When increasing B incorporation, we increasingly observe small precipitates, filaments with higher active B concentration and stacking faults. At the highest concentrations studied, large precipitates form, related to the decrease of active B concentration. The structural deformation, defect type and concentration, and active B distribution are connected to the initial increase and subsequent gradual loss of superconductivity

"Can the subaltern speak?" : The senses attributed to Lian Gong's offer by Community Health Workes

Orientador: Nelson Filice de BarrosTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciências MédicasResumo: Ao conduzirem grupos de práticas corporais como o Lian Gong, as/os Agentes Comunitárias/os de Saúde (ACS) trabalham com um conjunto de saberes e constroem estratégias pedagógicas para o cuidado e para a produção de saúde que desafiam e inovam a ordem instituída pela racionalidade científico-biomédica. Entretanto, apesar de provocarem uma transformação potente no cuidado, muitas vezes os conhecimentos produzidos por estas/es profissionais são subalternizados pelos saberes técnicos-especializados nos espaços institucionalizados da saúde. O objetivo desta pesquisa foi conhecer as experiências de ACS instrutor/as de Lian Gong nos serviços de atenção básica de Campinas/SP, compreendendo como produzem conhecimento a partir desse lugar. O "fazer metodológico" que norteou a pesquisa está fundamentado na proposta da metodologia-pedagogia de co-labor, uma prática político-reflexiva que possibilita romper com o esquema do pensamento hegemônico da ciência contemporânea e privilegiar o processo dialógico na construção do conhecimento. Com isso, colocamos em perspectiva uma articulação de práticas e reflexões que estão orientadas pelos princípios da interculturalidade, da interepistemicidade e da decolonialidade, trazendo para o centro do debate: as experiências com a desconstrução de práticas teóricas-metodológicas de pesquisa; os processos de regulação e de representação cultural sobre a categoria profissional "agente comunitário de saúde" produzidas em documentos publicados pela Organização Mundial da Saúde e pelo Ministério da Saúde, assim como em artigos científicos; e as construções identitárias a partir do "fazer-se" Agente Comunitário/a de Saúde no processo de trabalho em saúde. Foi possível compreender então que a subalternidade não é uma condição fixa para as/o ACS que participaram desta pesquisa. Há uma articulação de circunstâncias e de práticas de subalternização que estão em jogo no "fazer-se" ACS, como a etnicidade, o grau de escolaridade e a classe social. Contra práticas de subalternização, foi preciso não representar as/o agentes de saúde com nossas análises para então compreender os sentidos que as/o agentes de saúde atribuem às suas experiências, vivências, análises e reflexões em torno do trabalho com o lian gong e de questões outras que foram reveladas a partir dos nossos encontrosAbstract: By conducting groups of bodily practices groups such as Lian Gong, Community Health Workers (CHW) work with a set of knowledge and build pedagogical strategies for care and health production that challenge and innovate the order established by scientific-biomedical rationality. However, despite causing a powerful transformation in care, often the knowledge produced by these professionals is subordinated to the technical expertise in institutionalised health spaces. The objective of this research was to get to know the experiences of Lian Gong's CHW instructors in the basic care services in Campinas/SP, understanding how they produce knowledge from this place. The "methodological doing" that guided the research is based on the proposal of the co-labor-pedagogy methodology, a political-reflexive practice that makes it possible to break with the hegemonic thinking scheme of contemporary science and privilege the dialogic process in the construction of knowledge. With this, we put into perspective an articulation of practices and reflections that are guided by the principles of interculturality, interepistemicity and decoloniality, bringing to the center of the debate: the experiences with the deconstruction of theoretical-methodological research practices; the processes of regulation and cultural representation on the professional category "community health agent" produced in documents published by the World Health Organization and the Ministry of Health, as well as in scientific articles; and identity constructions from the "making" CHW in the health work process. It was then possible to understand that subordination is not a fixed condition for the CHW who participated in this research. There is an articulation of circumstances and practices of subalternity that are at stake and, contrary to what I initially imagined, the scientific-biomedical rationality is only one of the backgrounds that runs through these dynamics. Against subalternization practices, it was necessary not to represent Community Health Workers with our analyses to then understand the meanings that health agents attribute to their experiences, experiences, analyses and reflections around the work with lian gong and other issues that were revealed from our meetingDoutoradoCiências Sociais em SaúdeDoutora em Saúde Coletiva001CAPE

Fernandez JCA, Campos M, Cazzuni DH, Fiorilo P. Juventude e segurança: projeto Osasco. São Paulo: Editora Hucitec, Cepedoc Cidades Sustentáveis; 2010.

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Three-dimensional full-field X-ray orientation microscopy

International audienceA previously introduced mathematical framework for full-field X-ray orientation microscopy is for the first time applied to experimental near-field diffraction data acquired from a polycrystalline sample. Grain by grain tomographic reconstructions using convex optimization and prior knowledge are carried out in a six-dimensional representation of position-orientation space, used for modelling the inverse problem of X-ray orientation imaging. From the 6D reconstruction output we derive 3D orientation maps, which are then assembled into a common sample volume. The obtained 3D orientation map is compared to an EBSD surface map and local misorientations, as well as remaining discrepancies in grain boundary positions are quantified. The new approach replaces the single orientation reconstruction scheme behind X-ray diffraction contrast tomography and extends the applicability of this diffraction imaging technique to material micro-structures exhibiting sub-grains and/or intra-granular orientation spreads of up to a few degrees. As demonstrated on textured sub-regions of the sample, the new framework can be extended to operate on experimental raw data, thereby bypassing the concept of orientation indexation based on diffraction spot peak positions. This new method enables fast, three-dimensional characterization with isotropic spatial resolution, suitable for time-lapse observations of grain microstructures evolving as a function of applied strain or temperature

Uniaxial compression of calcite single crystals at room temperature: insights into twinning activation and development

E-twinning is a common plastic deformation mechanism in calcite deformed at low temperature. Strain rate, temperature and confining pressure have negligible effects on twinning activation which is mainly dependent on differential stress. The critical resolved shear stress (CRSS) required for twinning activation is dependent on grain size and strain hardening. This CRSS value may obey the Hall–Petch relation, but due to sparse experimental data its actual evolution with grain size and strain still remains a matter of debate. In order to provide additional constraints on twinning activation and development, new mechanical tests were carried out at room temperature on unconfined single crystals of calcite, with different sizes and crystallographic orientations. Uniaxial deformation was performed at a controlled displacement rate, while the sample surface was monitored using optical microscopy and a high-resolution CCD (charge-coupled device) camera. The retrieved macroscopic stress–strain behavior of the crystals was correlated with the surface observations of the deformation process. Results show (1) the onset of crystal plasticity with the activation of the first isolated mechanical twins during the strain hardening stage, and (2) the densification and thickening of twin lamellae during the steady-state flow stress stage. Such thickening of twin lamellae at room temperature emphasizes that calcite twin morphology is not controlled solely by temperature. The different values for the CRSS obtained for the activation of isolated twins and for the onset of twin densification and thickening raises questions regarding the appropriate value to be considered when using calcite twin data for stress inversion purposes.</p

Assessment of ankle muscle fatigue resistance with a destabilization tool

Background : L’entorse latérale de cheville est la blessure de cheville la plus fréquente. La fatigue semble jouer un rôle dans ce traumatisme car c’est en fin de match (de football ou le rugby) que l’entorse de cheville se produit le plus souvent. L’objectif de cette étude est d’évaluer la reproductibilité d’un test de résistance à la fatigue et d’analyser les différences des scores obtenus en fonction des caractéristiques de notre population. Matériel & Méthode : nous avons recruté 40 sujets volontaires actifs (25 hommes, 15femmes, 23.2±2.7ans) avec ou sans antécédent d’entorses. Ils ont réalisé un test de résistance à la fatigue en appui unipodal avec un outil de destabilisation Myolux®. Les sujets devaient réaliser un nombre maximal de répétitions d’inversion lente et d’éversion rapide. Ce test a été réalisé à deux reprises à une semaine d’intervalle. Des sous-catégories ont été formées dans notre population. Résultats : la reproductibilité relative était bonne ICC =0.80 [0.69-0.88] mais l’erreur de mesure était relativement élevée (SEM=4.85 et MDC :13.5). Une différence significative se dégage entre les sujets sains qui ont été statistiquement significativement meilleur que les sujets instables chroniques (p<0.02). Conclusion : Le test de résistance à la fatigue musculaire avec l’outil Myolux® est reproductible. Le nombre de répétitions du mouvement d’inversion/éversion semblent être plus faible chez des sujets avec une instabilité chronique de cheville, cependant pour objectiver une amélioration ou une différence entre les patients un écart de 14 répétitions est nécessaire.Background : Lateral ankle sprain is the most common ankle injury. Fatigue seems to play a role in this injury as it is at the end of a match (soccer or rugby) that ankle sprains occur most often. The objective of this study was to evaluate the reproducibility of a fatigue resistance test and to analyze the differences in the scores obtained according to the characteristics of our population. Material & Method: We recruited 40 active volunteers (25 men, 15 women, 23.2±2.7 years) with or without a history of sprains. They performed a unipodal support fatigue test with a Myolux® destabilization tool. The subjects had to perform a maximum number of repetitions of slow inversion and fast eversion. This test was performed twice at one week intervals. Subcategories were formed in our population. Results: The relative reproducibility was good ICC =0.80 [0.69-0.88] but the measurement error was relatively high (SEM=4.85 and MDC :13.5). A significant difference emerged between the healthy subjects who were statistically significantly better than the chronically unstable subjects (p<0.02). Conclusion: The muscle fatigue test with the Myolux® tool is reproducible. The number of repetitions of the inversion/eversion movement seems to be lower in subjects with chronic ankle instability, however to objectify an improvement or a difference between patients a difference of 14 repetitions is necessary

Biosynthesis of histone messenger RNA employs a specific 3’ end endonuclease

Replication-dependent (RD) core histone mRNA produced during S-phase is the only known metazoan protein-coding mRNA presenting a 3' stem-loop instead of the otherwise universal polyA tail. A metallo β-lactamase (MBL) fold enzyme, cleavage and polyadenylation specificity factor 73 (CPSF73), is proposed to be the sole endonuclease responsible for 3' end processing of both mRNA classes. We report cellular, genetic, biochemical, substrate selectivity, and crystallographic studies providing evidence that an additional endoribonuclease, MBL domain containing protein 1 (MBLAC1), is selective for 3' processing of RD histone pre-mRNA during the S-phase of the cell cycle. Depletion of MBLAC1 in cells significantly affects cell cycle progression thus identifying MBLAC1 as a new type of S-phase-specific cancer target

Proteomic and 3D structure analyses highlight the C/D box snoRNP assembly mechanism and its control

International audienceIn vitro, assembly of box C/D small nucleolar ribonucleoproteins (snoRNPs) involves the sequential recruitment of core proteins to snoRNAs. In vivo, however, assembly factors are required (NUFIP, BCD1, and the FISP90-R2TP complex), and it is unknown whether a similar sequential scheme applies. In this paper, we describe systematic quantitative stable isotope labeling by amino acids in cell culture proteomic experiments and the crystal structure of the core protein Snu 13p/15.5K bound to a fragment of the assembly factor Rsa1p/NUFIP. This revealed several unexpected features: (a) the existence of a protein-only pre-snoRNP complex containing five assembly factors and two core proteins, 15.5K and Nop58; (b) the characterization of ZNHIT3, which is present in the protein-only complex but gets released upon binding to C/D snoRNAs; (c) the dynamics of the R2TP complex, which,appears a to load/unload RuvBL AAA(+) adenosine triphosphatase from pre-snoRNPs; and (d) a potential mechanism for preventing premature activation of snoRNP catalytic activity. These data provide a framework for understanding the assembly of box C/D snoRNPs

Mutually Exclusive CBC-Containing Complexes Contribute to RNA Fate

The nuclear cap-binding complex (CBC) stimulates processing reactions of capped RNAs, including their splicing, 3′-end formation, degradation, and transport. CBC effects are particular for individual RNA families, but how such selectivity is achieved remains elusive. Here, we analyze three main CBC partners known to impact different RNA species. ARS2 stimulates 3′-end formation/transcription termination of several transcript types, ZC3H18 stimulates degradation of a diverse set of RNAs, and PHAX functions in pre-small nuclear RNA/small nucleolar RNA (pre-snRNA/snoRNA) transport. Surprisingly, these proteins all bind capped RNAs without strong preferences for given transcripts, and their steady-state binding correlates poorly with their function. Despite this, PHAX and ZC3H18 compete for CBC binding and we demonstrate that this competitive binding is functionally relevant. We further show that CBC-containing complexes are short lived in vivo, and we therefore suggest that RNA fate involves the transient formation of mutually exclusive CBC complexes, which may only be consequential at particular checkpoints during RNA biogenesis