367 research outputs found
Deep Neural Networks for energy reconstruction of Inverse Beta Decay events in JUNO
No full textThe Jiangmen Underground Neutrino Observatory (JUNO) is a scintillation detector, currently under construction, which aims to solve the neutrino mass hierarchy by measuring reactor electron antineutrino energy spectrum with a a resolution of 3%/sqrt(E(MeV)) – the highest ever achieved in a large mass neutrino detector. Several approaches for energy reconstruction are being evaluated on simulated data, and Deep Learning methods have already shown promising results, both in accuracy and in efficiency. In this work, a new Convolutional Neural Network with a rotational invariant architecture is trained on a small dataset of 160k instances, and is fine-tuned to exploit the detector’s spherical symmetry and make use of position and timing data from individual photomultipliers. This approach proves to be insensitive to the presence of dark noise from thermal fluctuations, leading to a (2.45+-0.03)% visual energy resolution at 2 MeV, only slightly higher than the 2.2% expected from theory, with a reconstruction bias well below 1%. However, a simpler Fully Connected Neural Network, replicated from previous work, which uses only integral data and is trained on a larger dataset (750k instances), leads to a slightly better resolution of (2.26+-0.05)% at 2 MeV, while being more sensitive to added noise – proving that there could still be some margin of improvement for more complex methods.ope
Deep Neural Networks per la ricostruzione dell’energia di eventi di decadimento beta inverso nell’esperimento JUNO
No full textModern experiments on the intensity frontier requires complicate algorithms to extract data for physical analysis. The neural
network techniques, having received a considerable boost during the last years, are becoming a useful tool for addressing many tasks
of data processing and provide in some cases better performance than traditional methods. The Jiangmen Underground Neutrino
Observatory (JUNO), a next generation experiment under construction in South of China, has been designed to measure the neutrino
mass hierarchy. Moreover, thanks to its large active mass, JUNO will be able to observe neutrinos coming from different sources:
solar neutrinos, atmospheric neutrinos, geo-neutrinos and neutrinos produced by the explosion of supernovae. The core of the
experiment is made of 20 kton Liquid Scintillator whose scintillation light is seen by almost 20000 large size (20") photo-multipliers
with high quantum efficiency, and by 25000 small size (3") photo-multipliers. The raw data will have to be further processed to
reconstruct the proper observables and for this task deep neural networks will be adopted for neutrino energy reconstruction. The
techniques are very powerful and allow to discriminate in an efficient way signal from background.ope
Synergestic induction of NRF-2 gene by curcumin and sulforaphane and pharmacokinetics/metabolism of 13C/Dim in rats by UPLC/MS
No full textCurcumin (CUR) and Sulforaphane (SFN) have shown remarkable cancer chemopreventive effects in numerous studies and combinations of low doses of chemopreventive agents can reduce toxicity while augmenting efficacy. The first part of the thesis investigated the chemotherapeutic effects elicited by a combination of CUR and SFN on human hepatocarcinoma
cells. The combination treatment- mediated effects on phase II/antioxidant enzymatic induction and antioxidant response element (ARE) was investigated. It was proposed that the combination of CUR and SFN could synergistically enhance the induction of ARE and the nuclear E2-factor related factor 2 (Nrf2)-mediated enzymes. Low doses of CUR and SFN significantly induced the expression of Nrf2-mediated enzymes, HO-1 and UGT1A1, promoted nuclear translocation of
Nrf2– a key regulator of phase II detoxifying /antioxidant enzymes – and synergistically induced the ARE luciferase activity. Chemical inhibitors of mRNA and protein synthesis affected the combination therapy- mediated transcriptional regulation of both HO-1 and UGT1A1. Synergism of CUR and SFN was evident at low concentrations. Such synergism in ARE-luciferase activity may partly explain the significant induction in the expression of Nrf2- mediated expression of HO-1 and UGT1A1 and the nuclear translocation of Nrf2, suggesting that a combination of low doses may be a promising strategy for cancer chemoprevention. For the second part of this thesis, a liquid chromatographic method was validated for the simultaneous analysis and pharmacokinetic evaluation of Indole-3-Carbinol (I3C), Diindolylmethane (DIM), and several I3C metabolites. I3C and DIM are naturally derived phytochemicals with promising in-vitro and
in-vivo anticarcinogenic properties. Using reversed-phase ultra performance liquid
chromatography (UPLC) coupled with mass spectrophotometry (MS), a rapid, specific, and high
throughput method was developed and validated for the quantification and identification of I3C, DIM, and other I3C metabolites in plasma. Recovery, linearity, precision, accuracy, and stability analysis fulfilled the CDER guidelines criteria. The method was successfully applied to the determination of the pharmacokinetic parameters and elucidation of metabolites of I3C or DIM
after oral, intravenous, or intraperitoneal administration to Sprague- Dawley rats.M.S.Includes bibliographical referencesIncludes vitaby Yury Y. Gome
JUNO's Perspective for Geoneutrinos
No full textJiangmen Underground Neutrino Observatory (JUNO) is a neutrino experiment being built in Southern China to measure neutrinos produced in nuclear power plants at a distance of 52.5 km. Having the main goal to improve the knowledge about neutrino oscillations, fundamental properties of these particles, JUNO will also be able to observe neutrinos of natural origin such as from the Sun, supernovae, the Earth atmosphere and its interior. The latter are called geoneutrinos and can serve as a proxy for investigation of the Earth’s radiogenic heat. Using inverse beta-decay as the detection channel, JUNO is sensitive to geoneutrinos produced in beta-decays of U-238 and Th-232 radioactive isotopes. JUNO will collect in one year about 400 geoneutrinos, what is more than the present-day statistics measured by Borexino and KamLAND together. This talk will report the JUNO expected sensitivity to geoneutrino measurement including some preliminary results of an updated analysis
UDP-glucose glycoprotein glucosyltransferase (uggt-1) and UPR genes modulate C. elegans necrotic cell death:
No full textContrary to an initial understanding of necrosis as a chaotic, non-regulated type of cell death, recent studies suggest that necrotic cell death (NCD) is a consequence of a complex and lethal cascade of genetically-encoded events. Necrosis underlies the pathology of many neurodegenerative diseases, stroke, and traumatic injury. In the Driscoll Lab, NCD mechanisms have been addressed for several years taking advantage of unique genetic and molecular biology tools developed in the model organism Caenorhabditis elegans. The necrotic paradigm we study the most involves initiation of cell death by hyperactivated ion channels expressed in six touch-sensory neurons and requires elevation of intracellular Ca2+, which activates calpain and cathepsin proteases.
I exploited the unique features of our model system to uncover novel genetic factors influencing this process. To this end, I conducted a high-throughput forward genetic screen to identify mutations that block or delay necrotic cell death induced by MEC-4(d) channel hyperactivation, and genetically mapped novel mutations capable of blocking or slowing the death process. I exploited an automated mutational screening capacity that allows sorting of individual animals based on detection of fluorescent signals that, in our particular case, had been engineered to indicate neuronal viability. I focused on the cloning of two novel mutant loci and dissected molecular mechanisms responsible for death suppression. In addition, I studied the impact of a major subset of calcium homeostasis genes in a C. elegans model of Aβ toxicity.
My research adds a new component to the current understanding of NCD, suggesting that inability to cope with endoplasmic reticulum stress (presumably induced by calcium depletion inside the ER, which affects chaperone functionality) plays an important role in progression through necrosis. I discovered that mild activation of an intact unfolded protein response (UPR), e.g., as induced by downregulation of UDP-glucose:glycoprotein glucosyltransferase (UGGT, an ER-resident enzyme involved in high-fidelity protein folding quality control) or mild increments in ambient temperature, can partially suppress necrosis in our C. elegans model, reminiscent of beneficial preconditioning effects in mammals. Additionally I found that several UPR transducers contribute to such modulation of cell death in a “tug-of-war” fashion. Our refined model of molecular mechanisms contributing and modulating necrosis suggests new strategies that could eventually limit the devastating effects of necrosis in human injury and disease.Ph.D.Includes bibliographical references (p. 154-174)by Yury Orlando Nunez Lope
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