616 research outputs found

    Supersymmetric Construction of W-Algebras from Super Toda and Wznw Theories

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    A systematic construction of super W-algebras in terms of the WZNW model based on a super Lie algebra is presented. These are shown to be the symmetry structure of the super Toda models, which can be obtained from the WZNW theory by Hamiltonian reduction. A classification, according to the conformal spin defined by an improved energy-momentum tensor, is dicussed in general terms for all super Lie algebras whose simple roots are fermionic . A detailed discussion employing the Dirac bracket structure and an explicit construction of W-algebras for the cases of OSP(1,2)OSP(1,2), OSP(2,2)OSP(2,2) , OSP(3,2)OSP(3,2) and D(2,1α)D(2,1 \mid \alpha ) are given. The N=1N=1 and N=2N=2 super conformal algebras are discussed in the pertinent cases.Comment: 24 page

    Second-line treatment in renal cell carcinoma: clinical experience and decision making

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    Currently, conventional treatments for metastatic RCC (mRCC) include immune-based combination regimens and/or targeted therapies, the latter mainly acting on angiogenesis, a key element of the process of tumor growth and spread. Although these agents proved able to improve patients’ outcomes, drug resistance and disease progression are still experienced by a substantial number of VEGFR-TKIs-treated mRCC patients. Following the inhibition of the VEGF/VEGFRs axis, two strategies have emerged: either specifically targeting resistance pathways, at the same time continuing to inhibit angiogenesis, or using a completely different approach aimed at re-activating the immune system through the use of inhibitors of specific negative immune checkpoints. These two approaches, practically represented by the use of either cabozantinib or nivolumab, seem to remain a rational therapeutic approach also when first-line immune-based combinations are used. The objective of this study is to design a preferential therapeutic pathway for the second-line treatment of mRCC. The procedure applied in this project was a group discussion, based on the Nominal Group Technique (NGT) method in a meeting session, aimed at defining the therapeutic choice for the second-line treatment of mRCC. The NGT process defined the most relevant parameters that, according to the interviewed panelists, clinicians should consider for the selection of the second-line therapy in the context of advanced renal cell carcinoma of mRCC. The algorithm developed for the treatment selection as a result of this process should thus be considered by clinicians as reference for therapy selection. Plain language summary: The result of this paper was the definition of an algorithm intended to suggest a preferential therapeutic pathway considering both the outputs of the Nominal Group Technique (NGT) process and the actual clinical practice and the experience of selected panelists. During the NGT process and the discussion phase, panelists defined the most important parameters to be included in the algorithm that are important for the treatment definition. Cabozantinib and nivolumab are identified as the most reasonable therapeutic options for patients progressing after first-line treatment and are the medication options included in the algorithm for therapy selection

    Gribov horizon and i-particles: about a toy model and the construction of physical operators

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    Restricting the functional integral to the Gribov region Ω\Omega leads to a deep modification of the behavior of Euclidean Yang-Mills theories in the infrared region. For example, a gluon propagator of the Gribov type, k2k4+γ^4\frac{k^2}{k^4+{\hat \gamma}^4}, can be viewed as a propagating pair of unphysical modes, called here ii-particles, with complex masses ±iγ^2\pm i{\hat \gamma}^2. From this viewpoint, gluons are unphysical and one can see them as being confined. We introduce a simple toy model describing how a suitable set of composite operators can be constructed out of ii-particles whose correlation functions exhibit only real branch cuts, with associated positive spectral density. These composite operators can thus be called physical and are the toy analogy of glueballs in the Gribov-Zwanziger theory.Comment: 35 pages, 10 .pdf figures. v2: version accepted for publication in Physical Review

    Percolation in real Wildfires

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    This paper focuses on the statistical properties of wild-land fires and, in particular, investigates if spread dynamics relates to simple invasion model. The fractal dimension and lacunarity of three fire scars classified from satellite imagery are analysed. Results indicate that the burned clusters behave similarly to percolation clusters on boundaries and look more dense in their core. We show that Dynamical Percolation reproduces this behaviour and can help to describe the fire evolution. By mapping fire dynamics onto the percolation models the strategies for fire control might be improved.Comment: 8 pages, 3 figures, epl sytle (epl.cls included

    The quest for improving treatment of cancer of unknown primary (CUP) through molecularly-driven treatments: a systematic review

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    Background: Carcinomas of unknown primary (CUP) account for 3-5% of all malignancy and, despite a reduction in incidence, the overall survival has not improved over the last decade. Chemotherapy regimens have not provided encouraging results. New diagnostic technologies, such as next generation sequencing (NGS), could represent a chance to identify potentially targetable genomic alterations in order to personalize treatment of CUP and provide insights into tumor biology. Methods: A systematic review of studies of patients with CUP, whose tumor specimen was evaluated through a NGS panel, has been performed on June 10th, 2019 according to PRISMA criteria from PubMed, ASCO meeting library and Clinicaltrial.gov. We have identified potentially targetable alterations for which approved/off-label/in clinical trials drugs are available. Moreover, we have included case reports about CUP patients treated with targeted therapies driven by NGS results in order to explore the clinical role of NGS in this setting. Results: We have evaluated 15 publications of which eleven studies (9 full-text articles and 2 abstracts) have analyzed the genomic profiling of CUPs through NGS technology, with different platforms and with different patients cohorts, ranging from 16 to 1,806 patients. Among all these studies, 85% of patients demonstrated at least one molecular alteration, the most frequent involving TP53 (41.88%), KRAS (18.81%), CDKN2A (8.8%), and PIK3CA (9.3%). A mean of 47.3% of patients harbored a potentially targetable alteration for which approved/off-label/in clinical trials drugs were available. Furthermore, we have identified 4 case reports in order to evaluate the clinical relevance of a specific targeted therapy identified through NGS. Conclusions: NGS may represent a tool to improve diagnosis and treatment of CUP by identifying therapeutically actionable alterations and providing insights into tumor biology

    Mandibular reconstruction with bridging customized plate after ablative surgery for ONJ: A multi‐centric case series

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    Purpose: Computer‐aided methods for mandibular reconstruction have improved both functional and morphological results in patients who underwent segmental mandibular resection. The purpose of this study is to evaluate the overlaying of virtual planning in terms of measures of the Computer Assisted Design/Computer Assisted Manufacturing CAD/CAM plate for mandibular reconstruction in patients who are ineligible for the insertion of reconstructing the titanium plate supported by fibular free flap, due to their poor health status, or in the presence of specific contraindications to autologous bone flap harvest. Materials and methods: The retrospective study performed analyzed the results of nine patients. The patients were treated at the Maxillofacial Surgery Unit of Policlinico S. Orsola of Bologna, Italy, and Policlinico San Marco, Catania, Italy, from April 2016 to June 2021. Superimposition between planning and post operative Computed Tomography CT scan was performed to assess the accuracy. Results: All reconstructive procedures were carried out successfully. No microsurgery‐related complications occurred. In two cases, we had plate misplacement, and in one case, plate exposure that led to plate removal. The average accuracy of the series assessed after CT superimposition, as previously described, was 0.95 mm. Conclusions: Considering that microvascular bone transfer is a high‐risk procedure in BRONJ patients, we can conclude that the positioning of a customized bridging mandibular prosthesis (CBMP), whether or not it is associated with a microvascular soft tissue transfer, is a safe technique in terms of surgical outcome and feasibility

    Measuring forest fragmentation using multitemporal remotely sensed data: three decades of change in the Dry Chaco

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    We introduce an approach based on remotely sensed data to summarize forest fragmentation over time, which specifically accounts for the interdependencies between landscape composition and configuration changes. The proposed method consists of five steps: i) multitemporal landscape sampling, ii) calculation of selected landscape pattern indices, iii) statistical comparison, iv) construction of sampled-based relationship spaces, and v) trajectory analysis. To show how the proposed method works in practice we examined the multitemporal fragmentation of the Arid Chaco forest in central Argentina during the period 1979-2010 using forest maps derived from Landsat images. As shown by our results, the approach provides a consistent framework for the interpretation of landscape structural changes over time.Fil: Carranza, María Laura. Università degli Studi del Molise; ItaliaFil: Frate, Ludovico. Università degli Studi del Molise; ItaliaFil: Acosta, Alicia T. R.. Università degli Studi di Roma; ItaliaFil: Hoyos, Laura Emilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto Multidisciplinario de Biología Vegetal (p); ArgentinaFil: Ricotta, Carlo. Universidad de Roma; ItaliaFil: Cabido, Marcelo Ruben. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto Multidisciplinario de Biología Vegetal (p); Argentin

    Are Long Term Cryopreservation and Patency of Vein Allograft Truly Achievable?

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    Despite extensive experimental work, neither the effect of long term cryopreservation on vein graft architecture nor the failure of alloveins due to graft rejection have yet been investigated. Herein, we investigated ultrastructurally: a) the integrity of rabbit jugular veins following 1, 2 and 3 months of cryopreservation; b) the outcome of the three-month cryopreserved vein auto- and allografts after 1 month of implantation in the rabbit carotid artery; and c) the immunologic response to cryopreserved vein allografts with and without seeded autologous endothelium. Prior to implantation, the cryopreserved rabbit veins were well-maintained except for endothelial cell damage. Following implantation, the cryopreserved vein autografts were comparable to fresh veins with a complete endothelial lining. Conversely, only one of the allograft was still patent with features of acute rejection. After seeding with autologous endothelium , these explants failed shortly after surgery. We found absence of endothelium and necrosis of the media components with neutrophil infiltration. Although three months of cryopreservation does not affect vein graft architecture significantly, endothelial cells are damaged irrespective of the time of cryopreservation. Vein autografts promptly healed after one month of implantation at which time a viable endothelial cell lining was restored from the host artery. Conversely, vein allografts, with and without seeded autologous endothelium, failed due to graft rejection. This study highlights that current methods of cryopreservation do not reduce antigenicity of venous allografts significantly
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