Synthesis, characterization and application of polyacrylate/silica hybrid films for coatings

Il degrado dovuto agli agenti atmosferici e il deterioramento degli edifici storici e di molti monumenti o sculture in pietre naturali è un problema conosciuto fin dall'antichità. L'obiettivo del progetto è quello di ottenere un prodotto innovativo basato sull'aggiunta di nanoparticelle di silice durante la sintesi del lattice, ottenendo una dispersione con elevata omogeneità nei film ibridi, che possano migliorare la stabilità meccanica del semplice rivestimento acrilico e la compatibilità tra i materiali lapidei e il rivestimento. L'idea è, da un lato, di utilizzare sistemi a base d'acqua per ridurre l'impatto ambientale e, dall'altro, di coniugare l'elevata stabilità termica e le buone proprietà meccaniche della silice con l'elasticità, la leggerezza e la capacità di formare rivestimenti di polimeri acrilici. Per migliorare la compatibilità tra fasi organiche e inorganiche, la silice è stata modificata con un metacrilossi (propil) trimetossisilano (MPS). Per la modifica della superficie della silice sono stati utilizzati due solventi, in particolare il metanolo e l'acqua e in entrambi i casi, sono stati ottenuti angoli di contatto elevati (79 ° per la silice modificata in acqua e 87 ° per la silice modificata in metanolo). Questi valori garantiscono un forte adsorbimento della silice all'interfaccia tra la fase acqua e la fase organica. Le dispersioni acquose composte da acrilico-silice sono state sintetizzate mediante polimerizzazione in miniemulsione, con la silice modificata e non modificata. Al fine di trovare la migliore formulazione con le migliori prestazioni, le dispersioni e i film sono stati caratterizzati mediante microscopia elettronica a trasmissione, microscopio a forza atomica, proprietà meccaniche, assorbimento dell'acqua, angoli di contatto, indentazione. Per comprendere il loro comportamento nel tempo, sono stati eseguiti dei test di invecchiamento accelerato sui film e sui film applicati su due pietre da costruzione naturali. Le prestazioni delle dispersioni sono state valutate come rivestimenti per marmo di Carrara e pietra leccese, due materiali spesso utilizzati nei beni culturali e con caratteristiche diverse. Essendo l'acqua una delle cause principali del deterioramento delle pietre naturali, sono stati eseguiti test di assorbimento dell'acqua capillare e il loro comportamento all’ essiccazione per misurare il comportamento idrofobico dei trattamenti. I risultati mostrano che l'aggiunta di nanosilice migliora la resistenza meccanica dei lattici e i trattamenti riducono l'assorbimento di acqua liquida per capillarità e allo stesso tempo consentono anche l’evaporazione dell’acqua, in totale accordo con le normative nel campo delle pietre protettive naturali, rendendoli adatti all'uso come rivestimenti protettivi

Mains savantes

Comment ont été fabriquées les reliques de la duchesse Françoise d'Amboise, béatifiée en 1863 et considérée comme la fondatrice des carmélites en France ? Les religieuses spécialisées dans la fabrication de ces objets auxquels est reconnue une valeur extrahumaine présentent leur pratique comme érudite. Cette pratique élitaire et secrète est transmise par voie initiatique. Elle est à la fois sous-tendue et conditionnée par la représentation même de la bienheureuse Françoise d'Amboise, construite au travers de la lecture et de la connaissance parfaite des textes hagiographiques la concernant.How was produced the making of relics of Françoise d'Amboise, Duchess of Brittany, who was beatified in 1863 and is considered as the founder of the Carmelites in France? The nuns who are specialised in the making of these objects (which are recognized as having a superhuman value) present their activity as an erudite one. This elitist, secret practice, which is handed on through initiatory transmission and based on a representation of Françoise d'Amboise is constructed through the reading and the perfect knowledge of specific hagiographic texts.¿Cómo fueron fabricadas las reliquias de la duquesa Françoise de Amboise, beatificada en 1863 y considerada como la fundadora de las carmelitas en Francia? Las religiosas especializadas en la fabricación de estos objetos a los cuales se atribuye un valor extrahumano presentan su práctica como erudita. Esta práctica elitista y secreta es transmitida por vía iniciática. Esta práctica es a la vez supuesta y condicionada por la representación misma de la bienaventurada Françoise de Amboise, construida a través de la lectura y del conocimiento perfecto de los textos hagiográficos que la involucran

Secrets de clôture : reliques et production de puissance sacrale (France et Italie contemporaines)

Sur la base d’une recherche ethnographique de terrain menée en France et en Italie, cette contribution interroge le concept de secret inhérent aux pratiques de production et de re-production de l’objet-relique dans la clôture chrétienne contemporaine. Elle s’intéresse aux traitements matériels et symboliques opérés principalement par des Carmélites sur les restes d’un saint ou d’un bienheureux. Plus encore, elle s’attache au rôle du secret dans le contrôle d’un processus et à l’apparition de compétences hiérarchisées, inscrites dans un système de communication réservé à une minorité. Il s’agit d’observer comment ces religieuses, s’étant soustraites à l’influence du clergé séculier, ont su – par le biais de pratiques dissimulées – s’aménager des niches de compétence et d’autonomie.On the basis of ethnographic fieldwork carried out in an Italian-French context, the notion of secrecy is considered within production, re-production and signification practices applied to relic-objects in the contemporary Christian monastic tradition. This study looks at the material and symbolic procedures performed on the remains of a saint or a blessed, principally by Carmelite nuns. It also looks at the role of secrecy in controlling a process and at the establishment of diversified roles, hierarchical sets of skills and a confidential communication system. Having eluded the influence of the secular clergy, these nuns are women who have attained precise areas of competence and autonomy

Inhabited silence: sound constructions of monastic spatiality

This paper is based on an extensive and engaged ethnographic study in which the researcher lived the life of a postulant in two French Carmelite monasteries. The aim is to discuss the relation between sound (auditory sensation) – here intended as silence, i. e. the absence of sound or noise – and monastic space, highlighting to what extent the construction of space is implemented on a basis which is mostly sound-related and how such a soundscape, in turn, can produce and preserve certain shared behaviours and life values. Thus, the focus is not so much on silence and its generally accepted devotional function as a medium for prayer; rather, the emphasis is placed on its social value as a performative, group-building and identity de/construction tool.O artigo baseia-se num estudo etnográfico extensivo no âmbito do qual a autora experimentou a vida de noviça em dois carmelos franceses. Pretende-se discutir a relação entre som (sensação auditiva) – aqui compreendido como silêncio, ou seja, como ausência de som ou rumor – e o espaço conventual, destacando até que ponto a construção do espaço é realizada, em grande medida, a partir do som, e como essa paisagem sonora pode, por sua vez, produzir e sustentar determinados comportamentos e valores partilhados. Assim, mais do que a função devocional do silêncio como meio para a oração, generalizadamente aceite, a ênfase é colocada no seu valor social como ferramenta performativa, de (des)construção identitária e de formação grupal

Dentate nucleus connectivity in adult patients with multiple sclerosis: functional changes at rest and correlation with clinical features

Background and objective: The dentate nucleus, which is the largest of the cerebellar nuclei, plays a critical role in movement and cognition. The aim of our study was to assess any changes in dentate functional connectivity (FC) in adult relapsing remitting multiple sclerosis (RR-MS) patients and to investigate possible clinical correlates. Materials and methods: In all, 54 patients and 24 healthy subjects (HS) underwent multimodal magnetic resonance imaging (MRI), including diffusion tensor imaging (DTI), three-dimensional-T1-weighted and resting state (RS) functional images; they also underwent a cognitive evaluation, that is, attention and information processing speed, by means of the Paced Auditory Serial Addition Test (PASAT). Patients were also scored according to Expanded Disability Status Scale (EDSS). RS-MRI data were analysed using FMRIB Software Library (FSL) tools, with the seed-based method to identify dentate FC. Results: When compared with HS, patients exhibited brain atrophy and widespread DTI abnormalities, as well as greater FC between the dentate nucleus and cortical areas, particularly in the frontal and parietal lobes. Within these areas, FC in patients correlated inversely with clinical impairment. Finally, FC correlated inversely with lesion load and microstructural brain damage. Conclusion: Our findings indicate that dentate FC at rest is altered in MS patients. Whether these functional changes are induced by the disease and play a compensatory role remains to be established

Functional connectivity changes and their relationship with clinical disability and white matter integrity in patients with relapsing-remitting multiple sclerosis

Background and objective: To define the pathological substrate underlying disability in multiple sclerosis by evaluating the relationship of resting-state functional connectivity with microstructural brain damage, as assessed by diffusion tensor maging, and clinical impairments. Methods: Thirty relapsing–remitting patients and 24 controls underwent 3T-MRI; motor abilities were evaluated by using measures of walking speed, hand dexterity and balance capability, while information processing speed was evaluated by a paced auditory serial addiction task. Independent component analysis and tract-based spatial statistics were applied to RS-fMRI and diffusion tensor imaging data using FSL software. Group differences, after dual regression, and clinical correlations were modelled with GeneralLinear-Model and corrected for multiple comparisons. Results: Patients showed decreased functional connectivity in 5 of 11 resting-state-networks (cerebellar, executive-control, medial-visual, basal ganglia and sensorimotor), changes in inter-network correlations and widespread white matter microstructural damage. In multiple sclerosis, corpus callosum microstructural damage positively correlated with functional connectivity in cerebellar and auditory networks. Moreover, functional connectivity within the medial-visual network inversely correlated with information processing speed. White matter widespread microstructural damage inversely correlated with both the paced auditory serial addiction task and hand dexterity. Conclusions: Despite the within-network functional connectivity decrease and the widespread microstructural damage, the inter-network functional connectivity changes suggest a global brain functional rearrangement in multiple sclerosis. The correlation between functional connectivity alterations and callosal damage uncovers a link between functional and structural connectivity. Finally, functional connectivity abnormalities affect information processing speed rather than motor abilities

Multiple sclerosis: changes in microarchitecture of white matter tracts after training with a video game balance board

Purpose: To determine if high-intensity, task-oriented, visual feedback training with a video game balance board (Nintendo Wii) induces significant changes in diffusion-tensor imaging (DTI) parameters of cerebellar connections and other supratentorial associative bundles and if these changes are related to clinical improvement in patients with multiple sclerosis.Conclusion: Despite the low statistical power (35%) due to the small sample size, the results showed that training with the balance board system modified the microstructure of superior cerebellar peduncles. The clinical improvement observed after training might be mediated by enhanced myelinationrelated processes, suggesting that high-intensity, taskoriented exercises could induce favorable microstructural changes in the brains of patients with multiple sclerosis.Materials and Methods: The protocol was approved by local ethical committee; each participant provided written informed consent. In this 24-week, randomized, two-period crossover pilot study, 27 patients underwent static posturography and brain magnetic resonance (MR) imaging at study entry, after the first 12-week period, and at study termination. Thirteen patients started a 12-week training program followed by a 12-week period without any intervention, while 14 patients received the intervention in reverse order. Fifteen healthy subjects also underwent MR imaging once and underwent static posturography. Virtual dissection of white matter tracts was performed with streamline tractography; values of DTI parameters were then obtained for each dissected tract. Repeated measures analyses of variance were performed to evaluate whether DTI parameters significantly changed after intervention, with false discovery rate correction for multiple hypothesis testing.Results: There were relevant differences between patients and healthy control subjects in postural sway and DTI parameters (P <.05). Significant main effects of time by group interaction for fractional anisotropy and radial diffusivity of the left and right superior cerebellar peduncles were found (F2,23 range, 5.555-3.450; P = .036-.088 after false discovery rate correction). These changes correlated with objective measures of balance improvement detected at static posturography (r = 20.381 to 0.401, P < .05). However, both clinical and DTI changes did not persist beyond 12 weeks after training

Waterborne Acrylate-Based Hybrid Coatings with Enhanced Resistance Properties on Stone Surfaces

The application of coating polymers to building materials is a simple and cheap way to preserve and protect surfaces from weathering phenomena. Due to its environmentally friendly character, waterborne coating is the most popular type of coating, and improving its performance is an important key of research. The study presents the results regarding the mechanical and photo-oxidation resistance of some water-based acrylic coatings containing SiO2 nanoparticles obtained by batch miniemulsion polymerization. Coating materials have been characterized in terms of hydrophobic/hydrophilic behavior, mechanical resistance and surface morphology by means of water-contact angle, and scrub resistance and atomic force microscopy (AFM) measurements depending on silica-nanoparticle content. Moreover, accelerated weathering tests were performed to estimate the photo-oxidation resistance of the coatings. The chemical and color changes were assessed by Fourier-transform infrared spectroscopy (FTIR) and colorimetric measurements. Furthermore, the nanofilled coatings were applied on two different calcareous lithotypes (Lecce stone and Carrara Marble). Its properties, such as capillary water absorption and color modification, before and after accelerated aging tests, were assessed. The properties acquired by the addition of silica nanoparticles in the acrylic matrix can ensure good protection against weathering of stone-based materials

Androgen modulation of pro-inflammatory and antiinflammatory cytokines during preadipocyte differentiation

Background: Macrophages and adipocytes contribute to release of cytokines resulting in the chronic inflammatory profile of the metabolic syndrome. The local increase of proinflammatory cytokines impairs adipogenesis, resulting in formation of dysfunctional adipocytes that are unable to store and handle lipids. The altered lipid fluxes in/from adipocytes affect whole-body metabolism. We investigated the role of androgens on adipocyte-derived proinflammatory and anti-inflammatory cytokines during preadipocyte differentiation. Materials and methods: Various differentiation methods were used to obtain full conversion of 3T3-L1 into mature adipocytes. The degree of adipocyte conversion in the presence/absence of dihydrotestosterone (DHT) was analyzed by measuring intracellular triglycerides (Oil Red O staining). The effects of DHT administration on interleukin 1Β (IL-1Β), IL-2, IL-6, IL-10, IL-12, interferon γ (IFNΓ) and tumor necrosis factor α (TNFα) secretion was measured at days 0, 4, 6 and 8 of differentiation using the SearchLight multiplex protein array. Results: DHT regulates a number of cytokines in committed and mature 3T3-L1 adipocytes. IL-1Β and TNFα were readily suppressed at the very early stages of differentiation. IFNΓ release was inhibited at day 4, but the effect was no longer detectable on day 8. IL-6 and IL-12 were significantly reduced at day 8 of differentiation. Conversely, the differentiation-dependent increase of IL-2 and IL-10 was further stimulated by DHT since day 0. Conclusions: We provide evidence that androgens promote an anti-inflammatory profile that parallels the acquisition of a functional adipocyte phenotype. The crosstalk between androgens, adipocyte-derived mediators of inflammation and intracellular lipid fluxes could have profound implications on metabolism of men with obesity and metabolic syndrome. © 2010, by Walter de Gruyter Berlin New York. All rights reserved

Effect of carbon nanostructures and fatty acid treatment on the mechanical and thermal performances of flax/polypropylene composites

Four different strategies for mitigating the highly hydrophilic nature of flax fibers were investigated with a view to increase their compatibility with apolar polypropylene. The effects of two carbon nanostructures (graphene nanoplatelets (GNPs) and carbon nanotubes (CNTs)), of a chemical modification with a fatty acid (stearic acid), and of maleated polypropylene on interfacial adhesion, mechanical properties (tensile and flexural), and thermal stability (TGA) were compared. The best performance was achieved by a synergistic combination of GNPs and maleated polypropylene, which resulted in an increase in tensile strength and modulus of 42.46% and 54.96%, respectively, compared to baseline composites. Stearation proved to be an effective strategy for increasing the compatibility with apolar matrices when performed in an ethanol solution with a 0.4 M concentration. The results demonstrate that an adequate selection of surface modification strategies leads to considerable enhancements in targeted properties