El ICMA instala un nuevo detector de neutrones en el Institut Laue-Langevin

Página web divulgativa.El Instituto de Ciencia Materiales de Aragón (ICMA) ha desarrollado un detector de neutrones, y ya lo está instalando en el Institut Laue-Langevin (ILL) de Grenoble (Francia), centro de referencia mundial en técnicas neutrónicas. Además, el Instituto gestionará para toda España los instrumentos españoles del ILL.Peer Reviewe

Two-neutrino double electron capture on 124Xe based on an effective theory and the nuclear shell model

We study the two-neutrino double electron capture on 124Xe based on an effective theory (ET) and large-scale shell model calculations, two modern nuclear structure approaches that have been tested against Gamow-Teller and double-beta decay data. In the ET, the low-energy constants are fit to electron capture and transitions around xenon. For the nuclear shell model, we use an interaction in a large configuration space that reproduces the spectroscopy of nuclei in this mass region. For the dominant transition to the 124Te ground state, we find half-lives y for the ET and y for the shell model. The ET uncertainty leads to a half-life almost entirely consistent with present experimental limits and largely within the reach of ongoing experiments. The shell model half-life range overlaps with the ET, but extends less beyond current limits. Our findings thus suggest that the two-neutrino double electron capture on 124Xe has a good chance to be discovered by ongoing or future experiments. In addition, we present results for the two-neutrino double electron capture to excited states of 124Te

Toward the discovery of matter creation with neutrinoless β β decay

The discovery of neutrinoless β β decay could soon be within reach. This hypothetical ultrarare nuclear decay offers a privileged portal to physics beyond the standard model of particle physics. Its observation would constitute the discovery of a matter-creating process, corroborating leading theories of why the Universe contains more matter than antimatter, and how forces unify at high energy scales. It would also prove that neutrinos and antineutrinos are not two distinct particles but can transform into each other, with their mass described by a unique mechanism conceived by Majorana. The recognition that neutrinos are not massless necessitates an explanation and has boosted interest in neutrinoless β β decay. The field stands now at a turning point. A new round of experiments is currently being prepared for the next decade to cover an important region of parameter space. In parallel, advances in nuclear theory are laying the groundwork to connect the nuclear decay with the underlying new physics. Meanwhile, the particle theory landscape continues to find new motivations for neutrinos to be their own antiparticle. This review brings together the experimental, nuclear theory, and particle theory aspects connected to neutrinoless β β decay to explore the path toward, and beyond, its discovery

A Proposal for a Modified Moller-Plesset Perturbation Theory

A modified version of the Moller-Plesset approach for obtaining the correlation energy associated to a Hartree-Fock ground state is proposed. The method is tested in a model of interacting fermions that allows for an exact solution. Using up to third order terms improved results are obtained, even more accurate in the limit of loosely bound particles. This result suggests the possible convenience of the scheme for the study of chemical bound problems.Comment: 10 pages, 1 figur

Preliminary results of the small animal rotational positron emisson tomography scanner

[Abstract] AMI Annual Conference 2004, March 27-31, Orlando, FloridaThis contribution reports preliminary results of a high-resolution small animal positron emission tomography (PET) based on pairs of opposed scintillation rotating detectors working in time coincidencePublicad

Nuclear shell‑model simulation in digital quantum computers

The nuclear shell model is one of the prime many-body methods to study the structure of atomic nuclei, but it is hampered by an exponential scaling on the basis size as the number of particles increases. We present a shell-model quantum circuit design strategy to find nuclear ground states by exploiting an adaptive variational quantum eigensolver algorithm. Our circuit implementation is in excellent agreement with classical shell-model simulations for a dozen of light and medium-mass nuclei, including neon and calcium isotopes. We quantify the circuit depth, width and number of gates to encode realistic shell-model wavefunctions. Our strategy also addresses explicitly energy measurements and the required number of circuits to perform them. Our simulated circuits approach the benchmark results exponentially with a polynomial scaling in quantum resources for each nucleus. This work paves the way for quantum computing shell-model studies across the nuclear chart and our quantum resource quantification may be used in configuration-interaction calculations of other fermionic systems

Structure–Biological Activity Relationships of Extra-Virgin Olive Oil Phenolic Compounds: Health Properties and Bioavailability

Extra-virgin olive oil is regarded as functional food since epidemiological studies and multidisciplinary research have reported convincing evidence that its intake affects beneficially one or more target functions in the body, improves health, and reduces the risk of disease. Its health properties have been related to the major and minor fractions of extra-virgin olive oil. Among olive oil chemical composition, the phenolic fraction has received considerable attention due to its bioactivity in different chronic diseases. The bioactivity of the phenolic compounds could be related to different properties such as antioxidant and anti-inflammatory, although the molecular mechanism of these compounds in relation to many diseases could have different cellular targets. The aim of this review is focused on the extra-virgin olive oil phenolic fraction with particular emphasis on (a) biosynthesis, chemical structure, and influence factors on the final extra-virgin olive oil phenolic composition; (b) structure–antioxidant activity relationships and other molecular mechanisms in relation to many diseases; (c) bioavailability and controlled delivery strategies; (d) alternative sources of olive biophenols. To achieve this goal, a comprehensive review was developed, with particular emphasis on in vitro and in vivo assays as well as clinical trials. This report provides an overview of extra-virgin olive oil phenolic compounds as a tool for functional food, nutraceutical, and pharmaceutical applications.Junta de Andalucía B-AGR-466-UGR1

Uptake and metabolism of olive oil polyphenols in human breast cancer cells using nano-liquid chromatography coupled to electrospray ionization–time of flight-mass spectrometry

Polyphenols from extra virgin olive oil (EVOO), a main component of the Mediterranean diet, have demonstrated repeatedly anti-tumor activity in several in vitro and in vivo studies. However, little is known about the efficiency of the absorption process and metabolic conversion of these compounds at cellular level. In this study, a nano liquid chromatography–electrospray ionization–time of flight mass spectrometry (nanoLC–ESI–TOF MS) method was developed to study the cellular uptake and metabolism of olive oil phenols in JIMT-1 human breast cancer cells. After incubation for different time periods with EVOO-derived phenolic extracts, culture media, cytosolic fraction and solid particles fraction were separated and analyzed. Most of the free phenols, mainly hydroxytyrosol, its secoiridoid derivatives, and the flavonoid luteolin, disappeared in the culture media in different ways and at different times. Besides, several metabolites were detected in the culture media, fact that may indicate absorption and intracellular metabolism followed by rapid cellular export. Low intracellular accumulation was observed with only traces of some compounds detected in the cytosolic and solid particles fractions. Methylated conjugates were the major metabolites detected, suggesting a catalytic action of catechol-O-methyl transferase (COMT) in cancer cells.The authors are very grateful to Ministry of Education and Science (FPU, AP2005-4356) and Junta de Andalucia (project P09-FQM-5469, project P07-AGR-02619 and AGL 2008-05108- CO3-03/ALI). Besides, this work was supported in part by Instituto de Salud Carlos III (Ministerio de Sanidad y Consumo, Fondo de Investigación Sanitaria – FIS, Spain, Grants CP05-00090, PI06-0778 and RD06-0020-0028)

Exact positioning for OSEM reconstructions on the atlas depth-of-interaction small animal scanner

[Abstract] AMI Annual Conference 2002, October 23 - 27Publicad

Features of the NIH atlas small animal pet scanner and its use with a coaxial small animal volume CT scanner

Proceeding of: 2002 IEEE International Symposium On Biomedical Imaging, Washington, D.C., USA, July 7-10, 2002ATLAS (Advanced Technology Laboratory Animal Scanner), a small animal PET scanner designed to image animals the size of rats and mice, is about to enter service on the NIH campus in Bethesda, Maryland. This system is the first small animal PET scanner with a depth-ofinteraction capability and the first to use iterative resolution recovery algorithms, rather than conventional filtered back projection, for "production" image reconstruction. ATLAS is also proximate to, and co-axial with, a high resolution small animal CT scanner. When fully integrated, spatially registered PET and CT images of each animal will be used to correct the emission data for radiation attenuation and to aid in target identification. In this report we describe some of the technical and functional features of this system and illustrate how these features are used in an actual small animal imaging studyThis work was supported in part by projects FIS 00/0036 and 11I PRICIT Comunidad de Madrid, Spain