560 research outputs found

    Numerical, Experimental and Analytical Correlation for Predicting the Structural Behavior of Composite Structures under Impact

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    Abstract In the present work, numerical, experimental and analytical results regarding impact events on composite structure are presented. The test case consists in a classic 24 plies CAI specimen (100Ă—150 mm) subjected to 10 J impact. The work can be divided into two phases. The first phase is finalized to the definition of a procedure able to provide a robust numerical model, which can simulate accurately the structural response of composite plates subjected to impact events. At this phase, the numerical results are compared with analytical ones. In the second phase, both inter- and intra-lamina failure are considered. Regarding the inter-laminar failure, an experimental-numerical procedure is defined in order to set the right parameters related to cohesive behaviour. For both phases, trade-off analyses on the main numerical parameters are performed. All numerical results are compared with experimental ones in terms of both energy balance and damaged area

    Influence of Eta-Phase on Wear Behavior of WC-Co Carbides

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    Cemented carbides, also known as Widia, are hard metals produced by sintering process and widely used in mechanical machining. They show high cutting capacity and good wear resistance; consequently, they result to be excellent materials for manufacturing cutting tools and sandblast nozzles. In this work, the wear resistance of WC-Co carbides containing Eta-phase, a secondary phase present in the hard metals when a carbon content deficiency occurs, is analyzed. Different mixtures of carbide are prepared and sintered, with different weight percentages of carbon, in order to form Eta-phase and then analyze how the carbon content influences the wear resistance of the material. This characterization is carried out by abrasive wear tests. The test parameters are chosen considering the working conditions of sandblast nozzles. Additional information is gathered through microscopic observations and the evaluation of hardness and microhardness of the different mixtures. The analyses highlight that there is a limit of carbon content below which bad sintering occurs. Considering the mixtures without these sintering problems, they show a wear resistance depending on the size and distribution of the Eta-phase; moreover, the one with high carbon content deficiency shows the best performance

    Gut barrier-microbiota imbalances in early life lead to higher sensitivity to inflammation in a murine model of C-section delivery

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    Background Most interactions between the host and its microbiota occur at the gut barrier, and primary colonizers are essential in the gut barrier maturation in the early life. The mother–ofspring transmission of microorganisms is the most important factor infuencing microbial colonization in mammals, and C‑section delivery (CSD) is an impor‑ tant disruptive factor of this transfer. Recently, the deregulation of symbiotic host‑microbe interactions in early life has been shown to alter the maturation of the immune system, predisposing the host to gut barrier dysfunction and infammation. The main goal of this study is to decipher the role of the early‑life gut microbiota‑barrier alterations and its links with later‑life risks of intestinal infammation in a murine model of CSD. Results The higher sensitivity to chemically induced infammation in CSD mice is related to excessive exposure to a too diverse microbiota too early in life. This early microbial stimulus has short‑term consequences on the host homeo‑ stasis. It switches the pup’s immune response to an infammatory context and alters the epithelium structure and the mucus‑producing cells, disrupting gut homeostasis. This presence of a too diverse microbiota in the very early life involves a disproportionate short‑chain fatty acids ratio and an excessive antigen exposure across the vulnerable gut barrier in the frst days of life, before the gut closure. Besides, as shown by microbiota transfer experiments, the microbiota is causal in the high sensitivity of CSD mice to chemical‑induced colitis and in most of the phenotypical parameters found altered in early life. Finally, supplementation with lactobacilli, the main bacterial group impacted by CSD in mice, reverts the higher sensitivity to infammation in ex‑germ‑free mice colonized by CSD pups’ microbiota. Conclusions Early‑life gut microbiota‑host crosstalk alterations related to CSD could be the linchpin behind the phe‑ notypic efects that lead to increased susceptibility to an induced infammation later in life in mice. Keywords C‑section delivery, Microbiota, Primary colonization, Early life, Infammation, Gut barrier, Murine modelinfo:eu-repo/semantics/publishedVersio

    Gut barrier-microbiota imbalances in early life lead to higher sensitivity to inflammation in a murine model of C-section delivery

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    Most interactions between the host and its microbiota occur at the gut barrier, and primary colonizers are essential in the gut barrier maturation in the early life. The mother-offspring transmission of microorganisms is the most important factor influencing microbial colonization in mammals, and C-section delivery (CSD) is an important disruptive factor of this transfer. Recently, the deregulation of symbiotic host-microbe interactions in early life has been shown to alter the maturation of the immune system, predisposing the host to gut barrier dysfunction and inflammation. The main goal of this study is to decipher the role of the early-life gut microbiota-barrier alterations and its links with later-life risks of intestinal inflammation in a murine model of CSD. The higher sensitivity to chemically induced inflammation in CSD mice is related to excessive exposure to a too diverse microbiota too early in life. This early microbial stimulus has short-term consequences on the host homeostasis. It switches the pup's immune response to an inflammatory context and alters the epithelium structure and the mucus-producing cells, disrupting gut homeostasis. This presence of a too diverse microbiota in the very early life involves a disproportionate short-chain fatty acids ratio and an excessive antigen exposure across the vulnerable gut barrier in the first days of life, before the gut closure. Besides, as shown by microbiota transfer experiments, the microbiota is causal in the high sensitivity of CSD mice to chemical-induced colitis and in most of the phenotypical parameters found altered in early life. Finally, supplementation with lactobacilli, the main bacterial group impacted by CSD in mice, reverts the higher sensitivity to inflammation in ex-germ-free mice colonized by CSD pups' microbiota. Early-life gut microbiota-host crosstalk alterations related to CSD could be the linchpin behind the phenotypic effects that lead to increased susceptibility to an induced inflammation later in life in mice

    Why Treat Patients with a Major Orthopaedic Surgery Only to Send Them Back to the Vulnerable Conditions That Made Them Sick in the First Place? A Conceptual Scenario to Improve Patient’s Journey

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    Individuals with severe cartilage degeneration of the hip or knee or collapsed vertebrae that cause spine deformities can suffer from joint and neuropathic pain in the back, disuse of the affected limb, and restriction of movements. Surgical intervention is the most widespread and successful solution to date. There is a general belief that eating healthy and staying physically and mentally active might have a preventive role against musculoskeletal disease occurrence, while instead, we are more certain of the benefits deriving from a healthy diet and exercise therapy after major orthopaedic procedures. These aspects are in fact vital components in enhanced recovery after surgery programmes. However, they are applied in hospital settings, are often centre-dependent, and lack primary and tertiary preventive efficacy since end once the patient is discharged. There is the lack of initiatives at the territorial level that ensure a continuum in the patient?s journey towards orthopaedic surgery, home transition, and a healthy and long-lasting life. The expert panel advocates the integration of an intermediate lifestyle clinic that promotes healthy eating, physical activity, and sleep hygiene. In this facility directed by professionals in enhancing recovery after surgery, patients can be referred after the surgical indication and before home discharge. Surgery is in fact a moment when individuals are more curious to do their best to heal and stay healthy, representing a timepoint and opportunity for educating patients on how lifestyle changes may optimise not only their surgical recovery but also long-term future health state

    Correlation between fibronectin binding protein A expression level at the surface of recombinant lactococcus lactis and plasmid transfer in vitro and in vivo

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    Background: Fibronectin Binding Protein A (FnBPA) is an invasin from Staphylococcus aureus that allows this pathogen to internalize into eukaryote cells. It was previously demonstrated that recombinant Lactococcus lactis expressing FnBPA were invasive and able to transfer a plasmid to eukaryotic cells in vitro and in vivo. In this study, the invasivity of recombinant strains of Lactococcus lactis that express FnBPA under the control of its constitutive promoter or driven by the strong nisin inducible expression system (NICE) were studied.Results: It was demonstrated that the nisA promoter allows an increase of FnBPA expression on the surface of Lactococcus lactis surface, as shown by flow cytometry, which subsequently enhanced internalization and plasmid transfer properties in vitro in Caco2 cells and Bone Marrow Dendritic Cells. In vivo, the use of nisA promoter increase the plasmid transfer in cells of both the small and large intestine of mice.Conclusion: FnBPA expression at the surface of recombinant L. lactis is positively correlated to internalization and DNA transfer properties. The recombinant strains of L. lactis that expresses FnBPA under the control of the nisin inducible expression system could thus be considered as an improved tool in the field of DNA transfer.Fil: Almeida, Juliana F.. Institut National de la Recherche Agronomique; Francia. Institut des sciences et industries du vivant et de l; FranciaFil: Mariat, Denis. Institut National de la Recherche Agronomique; Francia. Institut des sciences et industries du vivant et de l; FranciaFil: Azevedo, Vasco. Universidade Federal Do Minas Gerais;Fil: Miyoshi, Anderson. Universidade Federal Do Minas Gerais;Fil: de Moreno, Maria Alejandra. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; ArgentinaFil: del Carmen, Silvina Andrea. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; ArgentinaFil: Martin, Rebeca. Institut National de la Recherche Agronomique; Francia. Institut des sciences et industries du vivant et de l; FranciaFil: Langella, Philippe. Institut National de la Recherche Agronomique; Francia. Institut des sciences et industries du vivant et de l; FranciaFil: Leblanc, Jean Guy Joseph. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; ArgentinaFil: Chatel, Jean Marc. Institut National de la Recherche Agronomique; Francia. Institut des sciences et industries du vivant et de l; Franci

    Anti-nociceptive effect of Faecalibacterium prausnitzii in non-inflammatory IBS-like models

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    International audienceVisceral pain and intestinal dysbiosis are associated with Irritable Bowel Syndrome (IBS), a common functional gastrointestinal disorder without available efficient therapies. In this study, a decrease of Faecalibacterium prausnitzii presence has been observed in an IBS-like rodent model induced by a neonatal maternal separation (NMS) stress. Moreover, it was investigated whether F. prausnitzii may have an impact on colonic sensitivity. The A2-165 reference strain, but not its supernatant, significantly decreased colonic hypersensitivity induced by either NMS in mice or partial restraint stress in rats. This effect was associated with a reinforcement of intestinal epithelial barrier. Thus, F. prausnitzii exhibits anti-nociceptive properties, indicating its potential to treat abdominal pain in IBS patients

    Development of the Prevent for Work questionnaire (P4Wq) for assessment of musculoskeletal risk in the workplace: part 1-literature review and domains selection

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    Objective This study aims to define appropriate domains and items for the development of a self-administered questionnaire to assess the risk of developing work-related musculoskeletal disorder (WMSD) and the risk of its progression to chronicity. Design Literature review and survey study. Setting and participants A literature review and a two-round interview with 15 experts in musculoskeletal pain were performed to identify the available domains for WMSD assessment. Interventions and outcome To ensure quality, only validated questionnaires were included for the Delphi process. A three-round Delphi method, with three round steps, was used to select the most pertinent and relevant domains and items. Results Nine questionnaires were identified through the expert discussion and literature review, comprising 38 candidate domains and 504 items. In the first round of the Delphi group, 17 domains reached more than 70% agreement and were selected. In the second round, 10 domains were rejected, while 11 were selected to complete the pool of domains. In the third and final round, 89 items belonging to 28 domains were defined as significant to develop a WMSDs risk assessment questionnaire. Conclusions No specific risk assessment questionnaires for WMSDs were identified from the literature. WMSD risk of presence and chronicity can be defined by an assessment tool based on the biopsychosocial model and the fear-avoidance components of chronic pain. The present study provides the formulation and operationalisation of the constructs in domains and items needed for developing and validating the questionnaire

    A Web-based spatial decision supporting system for land management and soil conservation

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    Abstract. Today it is evident that there are many contrasting demands on our landscape (e.g. food security, more sustainable agriculture, higher income in rural areas, etc.) as well as many land degradation problems. It has been proved that providing operational answers to these demands and problems is extremely difficult. Here we aim to demonstrate that a spatial decision support system based on geospatial cyberinfrastructure (GCI) can address all of the above, so producing a smart system for supporting decision making for agriculture, forestry, and urban planning with respect to the landscape. In this paper, we discuss methods and results of a special kind of GCI architecture, one that is highly focused on land management and soil conservation. The system allows us to obtain dynamic, multidisciplinary, multiscale, and multifunctional answers to agriculture, forestry, and urban planning issues through the Web. The system has been applied to and tested in an area of about 20 000 ha in the south of Italy, within the framework of a European LIFE+ project (SOILCONSWEB). The paper reports – as a case study – results from two different applications dealing with agriculture (olive growth tool) and environmental protection (soil capability to protect groundwater). Developed with the help of end users, the system is starting to be adopted by local communities. The system indirectly explores a change of paradigm for soil and landscape scientists. Indeed, the potential benefit is shown of overcoming current disciplinary fragmentation over landscape issues by offering – through a smart Web-based system – truly integrated geospatial knowledge that may be directly and freely used by any end user (www.landconsultingweb.eu). This may help bridge the last very important divide between scientists working on the landscape and end users

    Functional homogeneous zones (fHZs) in viticultural zoning procedure: an Italian case study on Aglianico vine

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    Abstract. This paper aims to test a new physically oriented approach to viticulture zoning at farm scale that is strongly rooted in hydropedology and aims to achieve a better use of environmental features with respect to plant requirements and wine production. The physics of our approach are defined by the use of soil–plant–atmosphere simulation models, applying physically based equations to describe the soil hydrological processes and solve soil–plant water status. This study (part of the ZOVISA project) was conducted on a farm devoted to production of high-quality wines (Aglianico DOC), located in southern Italy (Campania region, Mirabella Eclano, AV). The soil spatial distribution was obtained after standard soil survey informed by geophysical survey. Two homogeneous zones (HZs) were identified; in each one a physically based model was applied to solve the soil water balance and estimate the soil functional behaviour (crop water stress index, CWSI) defining the functional homogeneous zones (fHZs). For the second process, experimental plots were established and monitored for investigating soil–plant water status, crop development (biometric and physiological parameters) and daily climate variables (temperature, solar radiation, rainfall, wind). The effects of crop water status on crop response over must and wine quality were then evaluated in the fHZs. This was performed by comparing crop water stress with (i) crop physiological measurement (leaf gas exchange, chlorophyll a fluorescence, leaf water potential, chlorophyll content, leaf area index (LAI) measurement), (ii) grape bunches measurements (berry weight, sugar content, titratable acidity, etc.) and (iii) wine quality (aromatic response). This experiment proved the usefulness of the physically based approach, also in the case of mapping viticulture microzoning
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