Renormalization group approach to Sudakov resummation in prompt photon production

We prove the all-order exponentiation of soft logarithmic corrections to prompt photon production in hadronic collisions, by generalizing an approach previously developed in the context of Drell-Yan production and deep-inelastic scattering. We show that all large logs in the soft limit can be expressed in terms of two dimensionful variables, and we use the renormalization group to resum them. The resummed results that we obtain are more general though less predictive than those proposed by other groups, in that they can accommodate for violations of Sudakov factorization.Comment: 21 pages, no figures. Final version to be published in Nucl. Phys. B. Discussion on colour structure added (eqs.(3.17)-(3.18)

EMT/MET at the crossroad of stemness, regeneration and oncogenesis. The Ying-Yang equilibrium recapitulated in cell spheroids

The epithelial-to-mesenchymal transition (EMT) is an essential trans-differentiation process, which plays a critical role in embryonic development, wound healing, tissue regeneration, organ fibrosis, and cancer progression. It is the fundamental mechanism by which epithelial cells lose many of their characteristics while acquiring features typical of mesenchymal cells, such as migratory capacity and invasiveness. Depending on the contest, EMT is complemented and balanced by the reverse process, the mesenchymal-to-epithelial transition (MET). In the saving economy of the living organisms, the same (Ying-Yang) tool is integrated as a physiological strategy in embryonic development, as well as in the course of reparative or disease processes, prominently fibrosis, tumor invasion and metastasis. These mechanisms and their related signaling (e.g., TGF-β and BMPs) have been effectively studied in vitro by tissue-derived cell spheroids models. These three-dimensional (3D) cell culture systems, whose phenotype has been shown to be strongly dependent on TGF-β-regulated EMT/MET processes, present the advantage of recapitulating in vitro the hypoxic in vivo micro-environment of tissue stem cell niches and their formation. These spheroids, therefore, nicely reproduce the finely regulated Ying-Yang equilibrium, which, together with other mechanisms, can be determinant in cell fate decisions in many pathophysiological scenarios, such as differentiation, fibrosis, regeneration, and oncogenesis. In this review, current progress in the knowledge of signaling pathways affecting EMT/MET and stemness regulation will be outlined by comparing data obtained from cellular spheroids systems, as ex vivo niches of stem cells derived from normal and tumoral tissues. The mechanistic correspondence in vivo and the possible pharmacological perspective will be also explored, focusing especially on the TGF-β-related networks, as well as others, such as SNAI1, PTEN, and EGR1. This latter, in particular, for its ability to convey multiple types of stimuli into relevant changes of the cell transcriptional program, can be regarded as a heterogeneous "stress-sensor" for EMT-related inducers (growth factor, hypoxia, mechano-stress), and thus as a therapeutic target

Threshold resummation of Drell-Yan rapidity distributions

We present a derivation of the threshold resummation formula for the Drell-Yan rapidity distribution. Our argument is valid for all values of rapidity and to all orders in perturbative QCD and can be applied to all Drell-Yan processes in a universal way, i.e. both for the production of a virtual photon \gamma^{*} and the production of a vector boson W^{\pm}, Z^{0}. We show that for the fixed-target experiment E866/NuSea used in current parton fits, the NLL resummation corrections are comparable to NLO fixed-order corrections and are crucial to obtain agreement with the data.Comment: 10 pages, 3 figures, Final versio

Nitric oxide, cytochrome c oxidase and myoglobin: Competition and reaction pathways

AbstractIt is relevant to cell physiology that nitric oxide (NO) reacts with both cytochrome oxidase (CcOX) and oxygenated myoglobin (MbO2). In this respect, it has been proposed [Pearce, L.L., et al. (2002) J. Biol. Chem. 277, 13556–13562] that (i) CcOX in turnover out-competes MbO2 for NO, and (ii) NO bound to reduced CcOX is “metabolized” in the active site to nitrite by reacting with O2. In contrast, rapid kinetics experiments reported in this study show that (i) upon mixing NO with MbO2 and CcOX in turnover, MbO2 out-competes the oxidase for NO and (ii) after mixing nitrosylated CcOX with O2 in the presence of MbO2, NO (and not nitrite) dissociates from the enzyme causing myoglobin oxidation

Luigi Einaudi

The present dictionary entry aims to provide an account of Luigi Einaudi's life, thought and work

Evidence for detrimental cross interactions between reactive oxygen and nitrogen species in Leber's hereditary optic neuropathy cells

Here we have collected evidence suggesting that chronic changes in the NO homeostasis and the rise of reactive oxygen species bioavailability can contribute to cell dysfunction in Leber’s hereditary optic neuropathy (LHON) patients.We report that peripheral blood mononuclear cells (PBMCs), derived froma female LHON patient with bilateral reduced vision and carrying the pathogenic mutation 11778/ND4, display increased levels of reactive oxygen species (ROS) and reactive nitrogen species (RNS), as revealed by flow cytometry, fluorometric measurements of nitrite/nitrate, and 3-nitrotyrosine immunodetection. Moreover, viability assays with the tetrazolium dye MTT showed that lymphoblasts from the same patient are more sensitive to prolonged NO exposure, leading to cell death. Taken together these findings suggest that oxidative and nitrosative stress cooperatively play an important role in driving LHON pathology when excess NO remains available over time in the cell environment

Cytochrome bd oxidase and nitric oxide: from reaction mechanisms to bacterial physiology.

International audience; Experimental evidence suggests that the prokaryotic respiratory cytochrome bd quinol oxidase is responsible for both bioenergetic functions and bacterial adaptation to different stress conditions. The enzyme, phylogenetically unrelated to the extensively studied heme-copper terminal oxidases, is found in many commensal and pathogenic bacteria. Here, we review current knowledge on the catalytic intermediates of cytochrome bd and their reactivity towards nitric oxide (NO). Available information is discussed in the light of the hypothesis that, owing to its high NO dissociation rate, cytochrome bd confers resistance to NO-stress, thereby providing a strategy for bacterial pathogens to evade the NO-mediated host immune attack

Interpreting Housing Prices with a MultidisciplinaryApproach Based on Nature-Inspired Algorithms and Quantum Computing

Current technology still does not allow the use of quantum computers for broader and individual uses; however, it is possible to simulate some of its potentialities through quantum computing. Quantum computing can be integrated with nature-inspired algorithms to innovatively analyze the dynamics of the real estate market or any other economic phenomenon. With this main aim, this study implements a multidisciplinary approach based on the integration of quantum computing and genetic algorithms to interpret housing prices. Starting from the principles of quantum programming, the work applies genetic algorithms for the marginal price determination of relevant real estate characteristics for a particular segment of Naples’ real estate market. These marginal prices constitute the quantum program inputs to provide, as results, the purchase probabilities corresponding to each real estate characteristic considered. The other main outcomes of this study consist of a comparison of the optimal quantities for each real estate characteristic as determined by the quantum program and the average amounts of the same characteristics but relative to the real estate data sampled, as well as the weights of the same characteristics obtained with the implementation of genetic algorithms. With respect to the current state of the art, this study is among the first regarding the application of quantum computing to interpretation of selling prices in local real estate markets