La sauvegarde des collections au musée des Monuments français: proposition d'une stratégie de réponse en cas d'incendie dans les galeries d'expositions permanentes

A la veille de travaux de restructuration portant sur la création d’un espace de restauration (complexe gastronomique), attenant aux parcours d’exposition, le musée des Monuments français (MMF) entreprend une réflexion sur la mise en place d’un plan de sauvegarde des oeuvres (PSO) en cas d’incendie. En effet, une période de réaffectation représente un risque accru de départ de feu. De nombreux sinistres ayant eu lieu dans des établissements culturels, avaient pour origine des travaux par points chaud. C’est dans ce contexte qu’Hélène Perrel, responsable du service Régie des oeuvres, nous a mandaté afin d’initier ce travail auprès de l’ensemble des collections exposées dans les galeries permanentes. Une préparation attentive et méthodique est l’unique solution pour limiter les conséquences d’un incendie majeur. Un plan de sauvegarde des collections est un dispositif opérationnel qui coordonne les actions de chacun des acteurs et anticipe les mesures à prendre, y compris pour la prise en charge des oeuvres sinistrées. C’est une réalisation de grande envergure, qui nécessite l’engagement de l’ensemble du personnel de l’institution, la collaboration des différents services et une coopération avec des intervenants divers. Ce travail se révèle donc en être une étude préalable. Les collections permanentes du MMF sont constituées d’oeuvres de nature et de typologie variées. D’une part, des moulages* et des peintures murales reproduisant, à grandeur et dans des matériaux différents de l’édifice d’origine, les plus grandes réalisations architecturales et décors peints français ; des oeuvres à l’apparence trompeuse, de véritables « puzzles » raccordés par sous-ensembles à l’aide d’un boisage et d’une ossature scellée aux murs du bâtiment. D’autre part, des maquettes, évoquant pour la majorité à l’échelle 1/1000 l’architecture contemporaine. Aussi la réponse à prévoir en cas de sinistre doit considérer ces deux modalités, l’évacuation d’oeuvres transportables et la protection in situ d’oeuvres inamovibles et monumentales. Après avoir dressé les particularités des collections du MMF ; l’organisation décisionnelle et fonctionnelle ainsi que les ressources nécessaires (humaines, matérielles, spatiales) au sauvetage en cas d’incendie majeur furent établis. Les solutions évoquées pour la protection de certaines oeuvres sont le fruit d’une investigation auprès des musées des Beaux-arts de Dijon et d’Orléans. Ces institutions ont réfléchi à des mesures protectrices en collaboration avec une entreprise spécialisée dans l’ignifugation des matériaux et le confinement de chantiers situés en zone sensible (construction navale, usine nucléaire). Ces dispositions peuvent se faire au moyen de bâches ignifugées conjuguées à une ossature métallique réalisée sur mesure, pouvant soit apporter un encadrement protecteur aux oeuvres (cabine), soit obstruer un espace (écran pop-up) afin d’éviter la propagation des flammes à cette zone.On the eve of restructuring work on the creation of a restaurant, adjacent to the permanent exhibition area, the Musée des Monuments Français (MMF) initiates a reflection on the establishment of an emergency plan in case of fire. Indeed, a reassignment period represents an increased risk of a fire starting. Many disasters that took place in cultural institutions were caused by hot work operations. A careful and methodical preparation is the only way to limit the consequences of a major fire. It is in this context that Hélène Perrel commissioned us to initiate this work on all the collections exhibited in the permanent galleries. A careful and methodical preparation is the only way to limit the consequences of a major fire. An emergency plan is an operational package that coordinates the actions of each player and anticipates measures, including restoration of affected works. This is a major achievement, which requires the commitment of all the institution's staff, the collaboration of different services and cooperation with the various stakeholders. This work will therefore be revealed in a preliminary study. The permanent collections of MMF consists in works of varied nature and typology. First, castings and murals reproducing in size and with different materials of the original building, the greatest architectural achievements and French painted decorations ; works with misleading appearance, true puzzles connected by subsets using a timbering and a frame sealed to the building walls. On the other hand, models, evoking in 1/1000 scale contemporary architecture. So, the answer to predict disaster must consider these two angles, the evacuation of transportable works and protecting the irremovable and monumental works. After outlining the features of the MMF collections, decisional and functional organization and resources (human, material, spatial) rescue in case of major fire were established. The solutions proposed for protection of certain works are the result of an investigation with the Museums of Fine Arts in Dijon and Orleans. These institutions reflected on protective measures in collaboration with a company specialized in fire protection of materials and containment sites located in sensitive areas. Such arrangements may be made with a canvas cover combined with custom made metal frame, which may give a protective supervision to the works (cabin) or clog a space (pop-up screen) to prevent the spread of flames in this area

Microscopic Model for High-spin vs. Low-spin ground state in [Ni2M(CN)8][Ni_2{M(CN)_8]} (M=MoV,WV,NbIVM=Mo^V, W^V, Nb^{IV}) magnetic clusters

Conventional superexchange rules predict ferromagnetic exchange interaction between Ni(II) and M (M=Mo(V), W(V), Nb(IV)). Recent experiments show that in some systems this superexchange is antiferromagnetic. To understand this feature, in this paper we develop a microscopic model for Ni(II)-M systems and solve it exactly using a valence bond approach. We identify the direct exchange coupling, the splitting of the magnetic orbitals and the inter-orbital electron repulsions, on the M site as the parameters which control the ground state spin of various clusters of the Ni(II)-M system. We present quantum phase diagrams which delineate the high-spin and low-spin ground states in the parameter space. We fit the spin gap to a spin Hamiltonian and extract the effective exchange constant within the experimentally observed range, for reasonable parameter values. We also find a region in the parameter space where an intermediate spin state is the ground state. These results indicate that the spin spectrum of the microscopic model cannot be reproduced by a simple Heisenberg exchange Hamiltonian.Comment: 8 pages including 7 figure

Spin-crossover compounds based on iron(II) complexes of 2,6-bis(pyrazol-1-yl)pyridine (bpp) functionalized with carboxylic acid and ethyl carboxylic acid

Four new salts of the iron(II) complex of the 2,6-bis( pyrazol-1-yl)pyridine ligand functionalized with a carboxylic acid group (bppCOOH) of formulas [Fe(bppCOOH)2](BF4)2 (1(BF4)2), [Fe(bppCOOH)2] (CF3SO3)2·yMe2CO (1(CF3SO3)2·yMe2CO), [Fe(bppCOOH)2](AsF6)2·yMe2CO (1(AsF6)2·yMe2CO) and [Fe (bppCOOH)2](SbF6)2·yMe2CO (1(SbF6)2·yMe2CO) have been prepared and characterized together with a more complete structural and photomagnetic characterization of the previously reported [Fe (bppCOOH)2](ClO4)2 (1(ClO4)2). Furthermore, the iron(II) complex of the ethyl ester derivative of bppCOOH (bppCOOEt) has been prepared and characterized (compound [Fe(bppCOOEt)2] (ClO4)2·yMe2CO, 2(ClO4)2·yMe2CO). Isostructural 1(BF4)2 and 1(ClO4)2 show an abrupt and reversible spin transition with a much lower T1/2 for the BF4− salt. CF3SO3 , SbF6 and AsF6 counteranions and the bppCOOEt ligand lead to the incorporation of solvent molecules in the structures, which play an important role in the spin-crossover properties of these compounds. In the case of 1(CF3SO3)2·yMe2CO, a spin transition is obtained after desolvation. All these compounds show a LIESST effect

Up-regulation of avian uncoupling protein in cold-acclimated and hyperthyroid ducklings prevents reactive oxygen species production by skeletal muscle mitochondria

<p>Abstract</p> <p>Background</p> <p>Although identified in several bird species, the biological role of the avian homolog of mammalian uncoupling proteins (avUCP) remains extensively debated. In the present study, the functional properties of isolated mitochondria were examined in physiological or pharmacological situations that induce large changes in avUCP expression in duckling skeletal muscle.</p> <p>Results</p> <p>The abundance of avUCP mRNA, as detected by RT-PCR in gastrocnemius muscle but not in the liver, was markedly increased by cold acclimation (CA) or pharmacological hyperthyroidism but was down-regulated by hypothyroidism. Activators of UCPs, such as superoxide with low doses of fatty acids, stimulated a GDP-sensitive proton conductance across the inner membrane of muscle mitochondria from CA or hyperthyroid ducklings. The stimulation was much weaker in controls and not observed in hypothyroid ducklings or in any liver mitochondrial preparations. The production of endogenous mitochondrial reactive oxygen species (ROS) was much lower in muscle mitochondria from CA and hyperthyroid ducklings than in the control or hypothyroid groups. The addition of GDP markedly increased the mitochondrial ROS production of CA or hyperthyroid birds up to, or above, the level of control or hypothyroid ducklings. Differences in ROS production among groups could not be attributed to changes in antioxidant enzyme activities (superoxide dismutase or glutathione peroxidase).</p> <p>Conclusion</p> <p>This work provides the first functional <it>in vitro </it>evidence that avian UCP regulates mitochondrial ROS production in situations of enhanced metabolic activity.</p

Molecular and all solid DFT studies of the magnetic and chemical bonding properties within KM[Cr(CN)6_6] (M = V, Ni) complexes

A study at both the molecular and extended solid level in the framework DFT is carried out for KM[Cr(CN)$_6$] (M = V, Ni). From molecular calculations, the exchange parameters J are obtained, pointing to the expected magnetic ground states, i.e., antiferromagnetic for M = V with J = -296.5 cm$^{-1}$ and ferromagnetic for M = Ni with J = +40.5 cm$^{-1}$. From solid state computations the same ground states and J magnitudes are confirmed from energy differences. Furthermore an analysis of the site projected density of states and of the chemical bonding is developed in which the cyanide ion linkage is analyzed addressing some isomerism aspects.Comment: new results, 5 tables, 7 fig

A RESPONSABILIDADE CIVIL PELA PERDA DE UMA CHANCE: UM ESTUDO À LUZ DA CIÊNCIA MÉDICA

Este artigo tem por objeto a análise da possibilidade de aplicação da teoria da perda de uma chance na responsabilidade civil médica. O objetivo da pesquisa é o estudo da referida teoria, analisando suas características e seus pressupostos para aplicação no direito médico. Em um primeiro momento, analisa-se a responsabilidade civil dos médicos e, posteriormente, aborda-se a teoria da perda de uma chance, seus aspectos históricos, conceitos e sua aplicação no direito brasileiro. Por fim, estuda-se a responsabilidade civil pela perda de uma chance na ciência médica e sua aplicação jurisprudencial. Para tanto, a investigação baseou-se o método dedutivo, operacionalizado com as técnicas de leitura dirigida, fichamento de obras e consultas nas jurisprudências pátrias. Os resultados da pesquisa demonstram que o ordenamento jurídico brasileiro aceita a aplicação da teoria da perda de uma chance na ciência médica, desde que preenchidos os pressupostos necessários, quais sejam, chance concreta, real, com alto grau de probabilidade de obter um benefício ou sofrer um prejuízo e o nexo de causalidade entre a perda da oportunidade de exercer a chance e a conduta do ofensor

Hypoxia refines plasticity of mitochondrial respiration to repeated muscle work

Purpose: We explored whether altered expression of factors tuning mitochondrial metabolism contributes to muscular adaptations with endurance training in the condition of lowered ambient oxygen concentration (hypoxia) and whether these adaptations relate to oxygen transfer as reflected by subsarcolemmal mitochondria and oxygen metabolism in muscle. Methods: Male volunteers completed 30 bicycle exercise sessions in normoxia or normobaric hypoxia (4,000m above sea level) at 65% of the respective peak aerobic power output. Myoglobin content, basal oxygen consumption, and re-oxygenation rates upon reperfusion after 8min of arterial occlusion were measured in vastus muscles by magnetic resonance spectroscopy. Biopsies from vastus lateralis muscle, collected pre and post a single exercise bout, and training, were assessed for levels of transcripts and proteins being associated with mitochondrial metabolism. Results: Hypoxia specifically lowered the training-induced expression of markers of respiratory complex II and IV (i.e. SDHA and isoform 1 of COX-4; COX4I1) and preserved fibre cross-sectional area. Concomitantly, trends (p<0.10) were found for a hypoxia-specific reduction in the basal oxygen consumption rate, and improvements in oxygen repletion, and aerobic performance in hypoxia. Repeated exercise in hypoxia promoted the biogenesis of subsarcolemmal mitochondria and this was co-related to expression of isoform 2 of COX-4 with higher oxygen affinity after single exercise, de-oxygenation time and myoglobin content (r≥0.75). Conversely, expression in COX4I1 with training correlated negatively with changes of subsarcolemmal mitochondria (r<−0.82). Conclusion: Hypoxia-modulated adjustments of aerobic performance with repeated muscle work are reflected by expressional adaptations within the respiratory chain and modified muscle oxygen metabolism