128 research outputs found

    Glazed roman ceramic. A multi-analytical approach

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    A multi-analytical approach has been applied to characterize ancient glazed ceramics from the archaeological sites of Magna Mater temple and Domus Tiberiana on the Palatine Hill (Rome, Italy) dated between the 3rd and the early 5th century AD. The aim of this work is to investigate the production technologies of the ceramic body and the glazed coating and to explore the nature and the provenance of the raw materials. Optical microscopy (OM), Fourier transform infrared spectroscopy (FTIR) and X-ray powder diffraction (XRPD) results showed that the ceramic body is composed by quartz, K-feldspar and plagioclase, fragments of igneous and sedimentary rocks. The firing temperature was estimated at about 900-1000 °C, in uncontrolled atmosphere conditions. The mineralogical assemblage of the ceramic body is consistent with a local source of the raw materials. The results of electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDS) showed that the glazes contain different Si/ Pb ratios. In addition, X-ray fluorescence (XRF) detected the presence of Sn although its concentration does not allow defining the studied samples as tin-glazed ceramics. However, the occurrence of this element indicates an atypical Roman production, never recognized before in coeval samples from other archaeological sites

    Use of recycled carbon fibre as an additive in the manufacture of porous bricks more durable against salt crystallization

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    Within the framework of the Sustainable Development Goals of the Agenda 2030, the circular economy is being promoted as a means of ensuring a sustainable use of resources and a reduction in the amount of waste produced. The aim is to reduce the demand for often scarce raw materials through the continuous reuse, recycling and regeneration of materials and products. This paper explores the use of carbon fibre from wind turbine blades as an additive in the production of new efficient bricks. Clay mixes with 0, 5 and 10 wt% additive were fired at three temperatures (800, 950 and 1100 ºC) and the fired bricks were analysed from mineralogical and physical points of view to determine their suitability for use in the construction industry. The results show that carbon fibre improves the durability of the bricks, which became 16 % more porous as the firing temperature increased. However, the compressive strength of the bricks with 10 wt% carbon fibre was about 50 % lower than that of the control bricks made without additive. It is interesting to note that the distribution of the carbon fibres within the brick varies considerably and that they are shorter and wider in the core of the samples. These results could offer an alternative line for new product development in the brick industry. The bricks tested here are an example of a circular economy in which waste from one industrial process (wind turbine blades) is reused as an input in another (brick manufacture). The environmental benefits achieved are twofold: reduced demand for clay and recycling of decommissioned turbine blades, which are currently amassed in wind turbine graveyards.Funding for open access charge Universidad de Granada/CBUA.Junta de Andalucía Research Group RNM179Research Project B-RNM-188-UGR20 of the Regional Ministry of University, Research and Innovation of the Junta de Andalucía and FEDER, a way of making Europ

    Selective Hydrogenations and Dechlorinations in Water Mediated by Anionic Surfactant Stabilized Pd Nanoparticles

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    We report a facile, inexpensive and green method for the preparation of Pd nanoparticles in aqueous medium stabilized by anionic sulfonated surfactants sodium 1-dodecanesulfonate 1a, sodium dodecylbenzenesulfonate 1b, dioctyl sulfosuccinate sodium salt 1c and poly(ethylene glycol) 4-nonylphenyl-3-sulfopropyl ether potassium salt 1d simply obtained by stirring aqueous solutions of Pd(OAc)2 with the commercial anionic surfactants further treated under hydrogen atmosphere for variable times. The aqueous Pd nanoparticles solutions were tested in the selective hydrogenation reactions of aryl-alcohols, -aldehydes and -ketones leading to complete conversion to the deoxygenated products even in the absence of strong Brønsted acids in the reduction of aromatic aldehydes and ketones, in the controlled semi-hydrogenation of alkynes leading to alkenes and in the efficient hydro-dechlorination of aromatic substrates. In all cases the micellar media were crucial to stabilize the metal nanoparticles, to dissolve substrates, to steer product selectivity and to enable recycling. What is interesting is also that a benchmark catalyst like Pd/C can be often surpassed in activity and/or selectivity in the reactions tested by simply switching to the appropriate commercially available surfactant, thereby providing an easy to use, flexible and practical catalytic system capable of efficiently addressing a variety of synthetically significant hydrogenation reactions

    How Diet Intervention via Modulation of DNA Damage Response through MicroRNAs May Have an Effect on Cancer Prevention and Aging, an in Silico Study

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    The DNA damage response (DDR) is a molecular mechanism that cells have evolved to sense DNA damage (DD) to promote DNA repair, or to lead to apoptosis, or cellular senescence if the damage is too extensive. Recent evidence indicates that microRNAs (miRs) play a critical role in the regulation of DDR. Dietary bioactive compounds through miRs may affect activity of numerous genes. Among the most studied bioactive compounds modulating expression of miRs are epi-gallocatechin-3-gallate, curcumin, resveratrol and n3-polyunsaturated fatty acids. To compare the impact of these dietary compounds on DD/DDR network modulation, we performed a literature search and an in silico analysis by the DIANA-mirPathv3 software. The in silico analysis allowed us to identify pathways shared by different miRs involved in DD/DDR vis-à-vis the specific compounds. The results demonstrate that certain miRs (e.g., -146, -21) play a central role in the interplay among DD/DDR and the bioactive compounds. Furthermore, some specific pathways, such as fatty acids biosynthesis/metabolism , extracellular matrix-receptor interaction and signaling regulating the pluripotency of stem cells , appear to be targeted by most miRs affected by the studied compounds. Since DD/DDR and these pathways are strongly related to aging and carcinogenesis, the present in silico results of our study suggest that monitoring the induction of specific miRs may provide the means to assess the antiaging and chemopreventive properties of particular dietary compounds

    Native extracellular matrix: a new scaffolding platform for repair of damaged muscle

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    Effective clinical treatments for volumetric muscle loss resulting from traumatic injury or resection of a large amount of muscle mass are not available to date. Tissue engineering may represent an alternative treatment approach. Decellularization of tissues and whole organs is a recently introduced platform technology for creating scaffolding materials for tissue engineering and regenerative medicine. The muscle stem cell niche is composed of a three-dimensional architecture of fibrous proteins, proteoglycans, and glycosaminoglycans, synthesized by the resident cells that form an intricate extracellular matrix (ECM) network in equilibrium with the surrounding cells and growth factors. A consistent body of evidence indicates that ECM proteins regulate stem cell differentiation and renewal and are highly relevant to tissue engineering applications. The ECM also provides a supportive medium for blood or lymphatic vessels and for nerves. Thus, the ECM is the nature's ideal biological scaffold material. ECM-based bioscaffolds can be recellularized to create potentially functional constructs as a regenerative medicine strategy for organ replacement or tissue repopulation. This article reviews current strategies for the repair of damaged muscle using bioscaffolds obtained from animal ECM by decellularization of small intestinal submucosa (SIS), urinary bladder mucosa (UB), and skeletal muscle, and proposes some innovative approaches for the application of such strategies in the clinical setting

    Lymphoepithelioma-like hepatocellular carcinoma: Case report and review of the literature

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    Lymphoepithelioma-like hepatocellular carcinoma (LELHCC) is a rare form of undifferentiated carcinoma of the liver characterized by the presence of an abundant lymphoid infiltrate. Here, a case of LEL-HCC is described. An 81-year-old woman with a chronic hepatitis C infection was referred to the general surgery department of our hospital in August 2013 with a diagnosis of HCC. A past ultrasound examination had revealed a 60 mm-diameter nodular lesion in the third segment of the liver. After a needle biopsy, the lesion was diagnosed as HCC. The patient underwent surgery with a liver segmentectomy. Two additional nodes on the gastric wall were detected during the surgical operation. The histology of the removed specimen showed a poorly differentiated HCC with significant lymphoid stroma. Immunohistochemical studies revealed that the epithelial component was reactive for CK CAM5.2, CK8, CK18, CEA (polyclonal) and was focally positive for hepar-1 and that the lymphoid infiltrate was positive for CD3, CD4 and CD8. The tumor cells were negative for Epstein-Barr virus. The gastric nodes were ultimately determined to be two small gastrointestinal stromal tumors (GISTs). The synchronous occurrence of HCC and GIST is another very uncommon finding rarely described in the literature. Here, we report the clinicopathological features of our case, along with a review of the few cases present in the literature

    Graphene-based nanomaterials for peripheral nerve regeneration

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    Emerging nanotechnologies offer numerous opportunities in the field of regenerative medicine and have been widely explored to design novel scaffolds for the regeneration and stimulation of nerve tissue. In this review, we focus on peripheral nerve regeneration. First, we introduce the biomedical problem and the present status of nerve conduits that can be used to guide, fasten and enhance regeneration. Then, we thoroughly discuss graphene as an emerging candidate in nerve tissue engineering, in light of its chemical, tribological and electrical properties. We introduce the graphene forms commonly used as neural interfaces, briefly review their applications, and discuss their potential toxicity. We then focus on the adoption of graphene in peripheral nervous system applications, a research field that has gained in the last years ever-increasing attention. We discuss the potential integration of graphene in guidance conduits, and critically review graphene interaction not only with peripheral neurons, but also with non-neural cells involved in nerve regeneration; indeed, the latter have recently emerged as central players in modulating the immune and inflammatory response and accelerating the growth of new tissue

    Restoration versus reconstruction: how cell anatomy and extra-cellular matrix influence tissue regeneration

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    Tissue regeneration replaces damaged cells and is involved in tissue remodeling. In order to investigate the existence of a leitmotif of tissue regeneration, we compared the cellular aspects of regeneration of epidermis, neurons and skeletal muscle, characterized by different types of histological and functional organization. Following damage, all the tissues here analyzed go through three phases: inflammation, regeneration and maturation. Another common feature is the occurrence of cellular de-differentiation and/or differentiation events, including gene transcription, which are typical of embryonic development. Nonetheless, various strategies are used by different tissues to replace their lost parts. The epidermis regenerates ex novo, whereas neurons restore their missing parts; muscle fibers use a mixed strategy, based on the regrowth of missing parts through reconstruction by means of newborn fibers. The choice of either strategy is influenced by the physical, chemical and structural features of the cells as well as by the extracellular matrix typical of a given tissue, which points to the existence of differential, evolutionary-based mechanisms for specific tissue regeneration. Taking skeletal muscle as a model, we present evidence about the importance of the fiber niche to direct and favour tissue regeneration, a phenomenon of particular relevance for highly hierarchized tissues such as striated muscles. Niche properties are accounted for by cell-cell contacts, cell-matrix interaction and paracrine effects in skeletal muscle. The ordered sequence of steps that characterizes the regeneration processes, shared by several tissues, suggests it may be possible to model this extremely important phenomenon to improve guided in situ regeneration interventions

    How microanalysis can be discriminant on black Pompeian wares

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    In the present work the advantages of punctual approaches are discussed in the discrimination of black wares from the Sanctuary of Venus Fisica (Pompeii, Italy), dated between the 2nd and 1st century BC. Black-gloss ware and "bucchero" samples are analyzed by a multi-analytical approach including optical microscopy (OM), X-ray powder diffraction (XRPD), scanning electron microscopy with Energy Dispersive Spectroscopy (SEM-EDS) and electron microprobe analysis (EMPA) to investigate the mineralogical and petrographic features of these artefacts. Grain size, firing conditions and potter’s expertise influenced the final appearance of the superficial decorative black layer. In addition, punctual chemical analysis was fundamental to verify the archaeological indication of specific production sites

    A dinâmica espacial da paisagem de Chapecó (SC): interpretação do processo de constituição do mosaico antropizado

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    The article discusses the study of the structure, transformation and dynamics of the landscape in the Sub-basin of Lajeado São José, city of Chapecó, state of Santa Catarina -Brazil from a bibliographic review and the use of the GIS tool for the mapping and morphological interpretation of the processes that constitute this morphological structure. As a theoretical criterion, the ecological interpretation of the landscape is interpreted as a means of understanding the territory, considering in this process its problems, conflicts and dynamics of space structuring, as well as the potential of social, economic, cultural and environmental order. In this respect, is revealed the anthropic mosaic of the heterogeneities/homogeneities of the constitution processes that allow the identification and definition of the Landscape Units (UP), being a means of structuring the territory, as well as of articulating effective actions for planning in the scale of the city/fragment/sub-basin. From the data collected, it is verified how the ecological thinking supports the necessary improvement of public policies – in this case, when it is proposed to redesign the macro-zoning in light of the landscape spatial dynamics of Chapecó – and thus presenting itself as a viable alternative for the Macroplanning of counties.Este artigo aborda a estruturação, transformação e dinâmica da paisagem na Sub-Bacia do Lajeado São José, no município de Chapecó, estado de Santa Catarina – Brasil, a partir de revisão bibliográfica e o uso da ferramenta GIS para o mapeamento e a interpretação tipo-morfológica dos processos que constituem essa estrutura. Como critério teórico, assume-se a interpretação ecológica da paisagem como um meio de compreender o território, considerando nesse processo suas problemáticas, conflitos e dinâmicas de estruturação do espaço, bem como as potencialidades de ordem social, econômica, cultural e ambiental. Nesse contexto, é revelado o mosaico antropizado das heterogeneidades/homogeneidades dos processos de constituição que possibilitam identificar e definir as unidades de paisagem, sendo essas um meio de estruturar o território e articular ações efetivas para o planejamento na escala da cidade/fragmento/sub-bacia. A partir dos dados levantados, demonstra-se como o pensamento ecológico fundamenta o necessário aprimoramento das políticas públicas – neste caso, ao propor o redesenho dos macrozoneamentos à luz da dinâmica espacial da paisagem de Chapecó – e, assim, se apresentando como uma alternativa viável para o macroplanejamento dos municípios
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