617 research outputs found

    Do You Remember Mitochondria?

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    Intraocular Biopsy and ImmunoMolecular Pathology for "Unmasking" Intraocular Inflammatory Diseases

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    Intraocular inflammation can hide a variety of eye pathologies. In 33% of cases, to obtain a correct diagnosis, investigation of the intraocular sample is necessary. The combined analyses of the intraocular biopsy, using immuno-pathology and molecular biology, point to resolve the diagnostic dilemmas in those cases where history, clinical tests, and ophthalmic and systemic examinations are inconclusive. In such situations, the teamwork between the ophthalmologist and the molecular pathologist is critically important to discriminate between autoimmune diseases, infections, and intraocular tumors, including lymphoma and metastases, especially in those clinical settings known as masquerade syndromes. This comprehensive review focuses on the diagnostic use of intraocular biopsy and highlights its potential to enhance research in the field. It describes the different surgical techniques of obtaining the biopsy, risks, and complication rates. The review is organized according to the anatomical site of the sample: I. anterior chamber containing aqueous humor, II. iris and ciliary body, III. vitreous, and IV. choroid and retina. We have excluded the literature concerning biopsy for choroidal melanoma and retinoblastoma, as this is a specialized area more relevant to ocular oncology

    The gravitational eikonal: from particle, string and brane collisions to black-hole encounters

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    Motivated by conceptual problems in quantum theories of gravity, the gravitational eikonal approach, inspired by its electromagnetic predecessor, has been successfully applied to the transplanckian energy collisions of elementary particles and strings since the late eighties, and to string-brane collisions in the past decade. After the direct detection of gravitational waves from black-hole mergers, most of the attention has shifted towards adapting these methods to the physics of black-hole encounters. For such systems, the eikonal exponentiation provides an amplitude-based approach to calculate classical gravitational observables, thus complementing more traditional analytic methods such as the Post-Newtonian expansion, the worldline formalism, or the Effective-One-Body approach. In this review we summarize the main ideas and techniques behind the gravitational eikonal formalism. We discuss how it can be applied in various different physical setups involving particles, strings and branes and then we mainly concentrate on the most recent developments, focusing on massive scalars minimally coupled to gravity, for which we aim at being as self-contained and comprehensive as possible.Comment: 208 pages, 19 figure

    Sirtuins and redox signaling interplay in neurogenesis, neurodegenerative diseases, and neural cell reprogramming

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    Since the discovery of Neural Stem Cells (NSCs) there are still mechanism to be clarified, such as the role of mitochondrial metabolism in the regulation of endogenous adult neurogenesis and its implication in neurodegeneration. Although stem cells require glycolysis to maintain their stemness, they can perform oxidative phosphorylation and it is becoming more and more evident that mitochondria are central players, not only for ATP production but also for neuronal differentiation's steps regulation, through their ability to handle cellular redox state, intracellular signaling, epigenetic state of the cell, as well as the gut microbiota-brain axis, upon dietary influences. In this scenario, the 8-oxoguanine DNA glycosylase (OGG1) repair system would link mitochondrial DNA integrity to the modulation of neural differentiation. On the other side, there is an increasing interest in NSCs generation, from induced pluripotent stem cells, as a clinical model for neurodegenerative diseases (NDs), although this methodology still presents several drawbacks, mainly related to the reprogramming process. Indeed, high levels of reactive oxygen species (ROS), associated with telomere shortening, genomic instability, and defective mitochondrial dynamics, lead to pluripotency limitation and reprogramming efficiency's reduction. Moreover, while a physiological or moderate ROS increase serves as a signaling mechanism, to activate differentiation and suppress self-renewal, excessive oxidative stress is a common feature of NDs and aging. This ROS-dependent regulatory effect might be modulated by newly identified ROS suppressors, including the NAD(+)-dependent deacetylase enzymes family called Sirtuins (SIRTs). Recently, the importance of subcellular localization of NAD synthesis has been coupled to different roles for NAD in chromatin stability, DNA repair, circadian rhythms, and longevity. SIRTs have been described as involved in the control of both telomere's chromatin state and expression of nuclear gene involved in the regulation of mitochondrial gene expression, as well as in several NDs and aging. SIRTs are ubiquitously expressed in the mammalian brain, where they play important roles. In this review we summarize the current knowledge on how SIRTs-dependent modulation of mitochondrial metabolism could impact on neurogenesis and neurodegeneration, focusing mainly on ROS function and their role in SIRTs-mediated cell reprogramming and telomere protection

    The eikonal operator at arbitrary velocities I: the soft-radiation limit

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    Observables related to the real part of the gravitational eikonal, such as the deflection angle and time delay, have been found so far to have a smooth post-Minkowskian (PM) expansion whose validity extends from the non-relativistic to the most extreme ultra-relativistic (UR) regime, which smoothly connects with massless particle collisions. To describe gravitational radiation, the eikonal phase has to be promoted to a unitary operator for which we motivate a proposal and start discussing properties in the soft-radiation limit. A convergent PM expansion is found to only hold below an UR bound (discussed in the GR literature in the seventies) above which a different expansion is instead needed implying, in general, some non-analyticity in Newton's constant. In this extreme UR regime soft radiative observables receive contributions only from gravitons and are therefore universal. This generalises the pattern discussed in \cite{DiVecchia:2020ymx} beyond the elastic case.Comment: 28 pages+reference

    Alta resolución diagnóstica de la sonografía para determinar desinserción del menisco

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    Se evaluó la capacidad de la sonografía en tiempo real para reconocer las lesiones de menisco. Se estudiaron por sonografía 124 rodillas en 62 pacientes con sospecha de lesión de menisco, correlacionandose los hallazgos con el examen clínico, la artrografía y la artroscopia. El estudio se llevó a cabo en el Departamento de Radiología y Ortopedia del Hospital Clementito Fraga Filho, entre los años 1995 y 2002. De los 50 diagnósticos confirmados de lesión del menisco, 36 presentaron alteraciones sonográficas. La desinserción del menisco se confirmó con cirugía en 24 pacientes, siendo bien visualizadas y reconocidas las alteraciones por sonografía en 22 de ellos, en tanto que se les identificó artrográficamente solo en 14 casos. Se encontraron algunos signos sonográficos muy específicos en el menisco con desinserción como área hipoecogénica en la base y fragmentación en 83.3% de los casos dando certeza en el diagnóstico de lesión en un porcentaje alto. Se concluye que la evaluación sonográfica es útil y debe ser considerada como método diagnóstico en los casos de sospecha de lesión del menisco.Trabajo académic

    Chapter Nemesi tecnologica, pace distopica: l’espropriazione della pace

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    Umberto Gori has often focused on the subject of peace, seen as the primary objective of Political Science, analysing the challenges that peacebuilding processes have to face in an international context undergoing profound change, and with aspects that could be described as dystopic. We will explore these dynamics by drawing inspiration from the way in which Ivan Illich dealt with the theme of the forced medicalisation of society, a theme that presents many points of contact with the intention of imposing a distorted version of the concept of peace, where a model of peaceful coexistence is proposed, which does not arise from the development of stable harmonious relations between mutually free and independent subjects, but from an absence of conflict produced by dehumanising forms of social conditioning
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