1,818 research outputs found

    An Almost Subharmonic Instability in the Flow Past Rectangular Cylinders

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    The three-dimensional instability of the flow past a 5 :1 rectangular cylinder is investigated via Floquet analysis and direct numerical simulations. A quasi-subharmonic (QS) unstable mode is detected, marking an important difference with the flow past bodies with lower aspect ratio and/or with smooth leading edge. The QS mode becomes unstable at Reynolds number (based on the cylinder thickness and free-stream velocity) Re approximate to 480; its spanwise wavelength is approximately three times the cylinder thickness. The structural sensitivity locates the wavemaker region over the longitudinal sides of the cylinder, indicating that the instability is triggered by the mutual inviscid interaction of vortices generated by the leading edge shear layer

    Housing Environmental Risk in Urban Areas: Cross Country Comparison and Policy Implications

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    The main aim of this paper is to assess whether there is a statistically significant environmental impact of cities within European countries. Second, starting from the estimated environmental impact of cities within European countries, the paper investigates whether cross-country variation can be explained by macro-economic factors and government policies which can play a role in mitigating such an impact. We start from individual evidence (EU-SILC data) to obtain a measure of the environmental impact of cities within countries, and then correlate the latter with macro variables to explain European heterogeneity. These estimates confirm that the environmental risk for households is particularly perceived in more densely populated urban agglomerations, although the marginal effects are quite heterogeneous between countries. Macroeconomic factors such as inequality, wealth, taxation and public spending on the environment, and macroeconomic constraints such as the public finance disequilibrium produce a strong heterogeneity between countries in determining the marginal effects of urban metropolises on household environmental risk

    Congenital growth hormone deficiency associated with hip dysplasia and Legg-Calve-Perthes disease

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    Objective: Growth hormone deficiency (GHD) is usually treated with recombinant human GH (rhGH), and this has been rarely associated with hip disorders. We analysed the clinical data of patients with congenital GHD receiving rhGH who had associated hip dysplasia or Legg‐Calve‐Perthes disease (LCPD), with a view to determining whether the hip dysplasia was associated with the underlying disease or with rhGH treatment. / Design: We performed a retrospective analysis of paediatric and adolescent patients seen between 1992–2018 with congenital GHD and hip disorders. Data were collected through a review of the patients’ medical records and included demographics, clinical and imaging data, and the time frame between the onset of the symptoms related to the hip disorders and the onset of GH treatment. / Results: Of the 13 patients with hip disorders, hip dysplasia was present in ten patients and LCPD in three. Hip dysplasia was diagnosed before rhGH was initiated in 50% of cases. These patients had bilateral hip dysplasia and isolated GHD. LCPD was diagnosed in one patient before rhGH was commenced and did not progress. In two patients, LCPD was diagnosed after rhGH was started and did temporarily progress in one of them, but rhGH was not discontinued because LCPD did not seem to be related to rhGH treatment. / Conclusions: This study suggests that hip dysplasia could be a manifestation of an underlying GHD. Additionally, rhGH treatment may not necessarily be causative of LCPD

    Six Sigma in European public health care : A proposed comparable model.

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    Six Sigma is commonly applied and well established in the manufacturing sector, especially in the USA. Since the beginning of the 1990s several public administrations, particularly in the field of health care, have also been implementing Six Sigma. In Europe, public health care is very different from US health care in terms of organisation and its relationship with stakeholders. A specific Six Sigma model for European public health care is missing from the literature. In order to gain real advantages for such a health care system it is worth analysing, discussing and designing a possible dedicated model and comparing it with the manufacturing one.The idea of such a comparison has originated from the Italian public health care system. In fact the Italian health care sector has a mission and values, a culture, an organisation, strategies and processes that are often very different from the production sector. However, many of these differences can also be found in European public health care. As described in the first chapter, among the European systems there are fundamental common features that can justify a dedicated research. In order to achieve the aim, the thesis has been conducted in two stages. Although the thesis is primarily deductive, the first stage is typically inductive and the second one is deductive. A third minor stage based on qualitative-inductive methods helps to put the finishing touches to the proposed model by showing the differences from the manufacturing model and the features of the European system. The final model attempts to make new contributions to the literature by primarily bringing knowledge to the stakeholders in the academic field and secondarily to the practitioners. The main contribution is surely a roadmap for shaping a missing Six Sigma model for European public health care

    Therapeutic Targeting of mTOR in T-Cell Acute Lymphoblastic Leukemia: An Update

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    T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive blood malignancy that arises from the clonal expansion of transformed T-cell precursors. Although T-ALL prognosis has significantly improved due to the development of intensive chemotherapeutic protocols, primary drug-resistant and relapsed patients still display a dismal outcome. In addition, lifelong irreversible late effects from conventional therapy are a growing problem for leukemia survivors. Therefore, novel targeted therapies are required to improve the prognosis of high-risk patients. The mechanistic target of rapamycin (mTOR) is the kinase subunit of two structurally and functionally distinct multiprotein complexes, which are referred to as mTOR complex 1 (mTORC1) and mTORC2. These two complexes regulate a variety of physiological cellular processes including protein, lipid, and nucleotide synthesis, as well as autophagy in response to external cues. However, mTOR activity is frequently deregulated in cancer, where it plays a key oncogenetic role driving tumor cell proliferation, survival, metabolic transformation, and metastatic potential. Promising preclinical studies using mTOR inhibitors have demonstrated efficacy in many human cancer types, including T-ALL. Here, we highlight our current knowledge of mTOR signaling and inhibitors in T-ALL, with an emphasis on emerging evidence of the superior efficacy of combinations consisting of mTOR inhibitors and either traditional or targeted therapeutics

    Roles of sorcin in drug resistance in cancer: one protein, many mechanisms, for a novel potential anticancer drug target

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    The development of drug resistance is one of the main causes of failure in anti-cancer treatments. Tumor cells adopt many strategies to counteract the action of chemotherapeutic agents, e.g., enhanced DNA damage repair, inactivation of apoptotic pathways, alteration of drug targets, drug inactivation, and overexpression of ABC (Adenosine triphosphate-binding cassette, or ATP-binding cassette) transporters. These are broad substrate-specificity ATP-dependent efflux pumps able to export toxins or drugs out of cells; for instance, ABCB1 (MDR1, or P-glycoprotein 1), overexpressed in most cancer cells, confers them multidrug resistance (MDR). The gene coding for sorcin (SOluble Resistance-related Calcium-binding proteIN) is highly conserved among mammals and is located in the same chromosomal locus and amplicon as the ABC transporters ABCB1 and ABCB4, both in human and rodent genomes (two variants of ABCB1, i.e., ABCB1a and ABCB1b, are in rodent amplicon). Sorcin was initially characterized as a soluble protein overexpressed in multidrug (MD) resistant cells and named “resistance-related” because of its co-amplification with ABCB1. Although for years sorcin overexpression was thought to be only a by-product of the co-amplification with ABC transporter genes, many papers have recently demonstrated that sorcin plays an important part in MDR, indicating a possible role of sorcin as an oncoprotein. The present review illustrates sorcin roles in the generation of MDR via many mechanisms and points to sorcin as a novel potential target of different anticancer molecules

    Survey and modelling for the bim of Basilica of San Marco in Venice

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    The Basilica of San Marco is a singular case in the field of Cultural heritage, as it constitutes a construction site always active for the maintenance and preservation of the basilica itself. The continuous intervention of conservation, due to the particular environmental conditions of Venice and the opening to the public, together with the complexity of the building itself, imposes the need to identify an optimized management system. For this reason, in 2013 the Procurator of St. Marco Basilica commissioned the construction of a 3D model of the Basilica to be used for the creation of a BIM. The model must meet the required precision of the scale of 1: 50, and should also include, in addition to the geometric description, a description of the mosaic and marble surfaces of the basilica through high resolution orthophoto which are essential for the restoration of the mosaics. The complexity of the church and the large and continuous flow of public led to work in non-optimal conditions especially for the acquisition stage. The basilica has certain peculiarities that led to some important choices, for example the use of photogrammetry instead of laser scanning technique. The same technique was preferred also by the need to realize, in addition to the geometric model, high-resolution orthophotos of marbles and mosaic surfaces. The modelling of the basilica has highlighted a number of problems related to the building features. The basilica, indeed, is the result of the juxtaposition of elements (capitals, columns) with different origin, which therefore cannot be standardized in special libraries. Moreover, especially in the extensive mosaic areas, there are not edges that characterize the architecture, but only beveled surfaces. This has resulted in a change also in the modeling paradigm with the need to identify alternative systems even for the construction of simple elements. Therefore, we decided to model using NURBS since it is the method that allows greater adherence to reality and, at the same time, a model with acceptable dimensions in terms of navigation and usability. Only the most sculptural pieces such as capitals and statues have been replaced by mesh models. As we were interested in different elaborations, the results of this work are a geometric NURBS model for the subsequent insertion into BIM environment, with the possibility of extracting two-dimensional drawings such as plans and sections, a mesh model with low resolution textures for online navigation and high resolution orthophotos. The survey work and modeling has been almost completed for the interior of the basilica whereas only the external remains to be acquired and modeled. For the management of the entire work it was decided to use the data organization system already used by the Politecnico di Milano for the Duomo di Milano. The BIM3DSURVEY system will be essential not only to manage the finished model, but it has been very useful also during the construction phase because it allows us to divide the entire work into more work units. However, this system required some changes to meet the peculiarity of this BIM, in particular the need to append and link the orthophotos to real surfaces, in order to use the model also as a spatial index for the images
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