92 research outputs found

    State-dependent Jastrow correlation functions for 4He nuclei

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    We calculate the ground-state energy for the nucleus 4He with V4 nucleon interactions, making use of a Jastrow description of the corresponding wavefunction with state-dependent correlation factors. The effect related to the state dependence of the correlation is quite important, lowering the upper bound for the ground-state energy by some 2 MeV.Comment: 10 pages, REVTeX, to be published in J. Phys. G: Nucl. Part. Phy

    Projected multicluster model with Jastrow and linear state dependent correlations for 12A1612 \leq A \leq 16 nuclei

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    Variational wave functions based on a Margenau-Brink cluster model with short range and state dependent correlations, and angular momentum projection are obtained for some nuclei with 12A1612 \leq A \leq 16. The calculations have been carried out starting from the nucleon-nucleon interaction by using the Variational Monte Carlo method. The configuration used consists of three alpha clusters located at the apexes of an equilateral triangle, and an additional cluster, not necessarily of alpha type, forming a tetrahedron. This cluster is located at the top of its height. Short-range and state dependent correlations are included by means of a central Jastrow factor and a linear operatorial correlation factor respectively. Angular momentum projection is performed by using the Peierls-Yoccoz operators. Optimal structures are obtained for all the nuclei studied. Some aspects of our methodology have been tested by comparing with previous calculations carried out without short range correlations. The binding energy, the root mean square radius, and the one- and two-body densities are reported. The effects of correlations on both the energy and the nucleon distribution are analyzed systematically.Comment: 19 pages, 6 figure

    Impaired autophagic flux is associated with increased endoplasmic reticulum stress during the development of NAFLD

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    This work is licensed under a Creative Commons Attribution-NonCommercialNoDerivs 3.0 Unported License.-- et al.The pathogenic mechanisms underlying the progression of non-alcoholic fatty liver disease (NAFLD) are not fully understood. In this study, we aimed to assess the relationship between endoplasmic reticulum (ER) stress and autophagy in human and mouse hepatocytes during NAFLD. ER stress and autophagy markers were analyzed in livers from patients with biopsy-proven non-alcoholic steatosis (NAS) or non-alcoholic steatohepatitis (NASH) compared with livers from subjects with histologically normal liver, in livers from mice fed with chow diet (CHD) compared with mice fed with high fat diet (HFD) or methionine-choline-deficient (MCD) diet and in primary and Huh7 human hepatocytes loaded with palmitic acid (PA). In NASH patients, significant increases in hepatic messenger RNA levels of markers of ER stress (activating transcription factor 4 (ATF4), glucose-regulated protein 78 (GRP78) and C/EBP homologous protein (CHOP)) and autophagy (BCN1) were found compared with NAS patients. Likewise, protein levels of GRP78, CHOP and p62/SQSTM1 (p62) autophagic substrate were significantly elevated in NASH compared with NAS patients. In livers from mice fed with HFD or MCD, ER stress-mediated signaling was parallel to the blockade of the autophagic flux assessed by increases in p62, microtubule-associated protein 2 light chain 3 (LC3-II)/LC3-I ratio and accumulation of autophagosomes compared with CHD fed mice. In Huh7 hepatic cells, treatment with PA for 8 h triggered activation of both unfolding protein response and the autophagic flux. Conversely, prolonged treatment with PA (24 h) induced ER stress and cell death together with a blockade of the autophagic flux. Under these conditions, cotreatment with rapamycin or CHOP silencing ameliorated these effects and decreased apoptosis. Our results demonstrated that the autophagic flux is impaired in the liver from both NAFLD patients and murine models of NAFLD, as well as in lipid-overloaded human hepatocytes, and it could be due to elevated ER stress leading to apoptosis. Consequently, therapies aimed to restore the autophagic flux might attenuate or prevent the progression of NAFLD.We acknowledge the following grant support: SAF2012-33283 (MINECO, Spain), Comunidad de Madrid S2010/BMD-2423, EFSD and Amylin Paul Langerhans Grant and Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM, ISCIII, Barcelona, Spain) to AMV.; SAF2010-16037, SAF2013-43713-R (MINECO) and Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBEREHD, ISCIII) to PMS. RD12/0042/0019 (ISCIII) and S2010/BMD-2478 (Comunidad de Madrid) to LB, PI 13/01299 and Fundación Mutua Madrileña 2012 to C G-M and AIRC IG-2012 to GMF.Peer Reviewe

    Crosstalk Between LXR and Caveolin-1 Signaling Supports Cholesterol Efflux and Anti-Inflammatory Pathways in Macrophages

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    © 2021 Ramírez, Torrecilla-Parra, Pardo-Marqués, de-Frutos, Pérez-García, Tabraue, de la Rosa, Martín-Rodriguez, Díaz-Sarmiento, Nuñez, Orizaola, Través, Camps, Boscá and Castrillo.Macrophages are immune cells that play crucial roles in host defense against pathogens by triggering their exceptional phagocytic and inflammatory functions. Macrophages that reside in healthy tissues also accomplish important tasks to preserve organ homeostasis, including lipid uptake/efflux or apoptotic-cell clearance. Both homeostatic and inflammatory functions of macrophages require the precise stability of lipid-rich microdomains located at the cell membrane for the initiation of downstream signaling cascades. Caveolin-1 (Cav-1) is the main protein responsible for the biogenesis of caveolae and plays an important role in vascular inflammation and atherosclerosis. The Liver X receptors (LXRs) are key transcription factors for cholesterol efflux and inflammatory gene responses in macrophages. Although the role of Cav-1 in cellular cholesterol homeostasis and vascular inflammation has been reported, the connection between LXR transcriptional activity and Cav-1 expression and function in macrophages has not been investigated. Here, using gain and loss of function approaches, we demonstrate that LXR-dependent transcriptional pathways modulate Cav-1 expression and compartmentation within the membrane during macrophage activation. As a result, Cav-1 participates in LXR-dependent cholesterol efflux and the control of inflammatory responses. Together, our data show modulation of the LXR-Cav-1 axis could be exploited to control exacerbated inflammation and cholesterol overload in the macrophage during the pathogenesis of lipid and immune disorders, such as atherosclerosis.We thank MINECO FPI predoctoral fellowship granted to MCO (BES-2015-075339). Experimental work was supported by grants from Ministerio de Ciencia, Investigación y Universidades, y Fondo Europeo de Desarrollo Regional (FEDER) Grant REF: PID2019-104284RB-I00/AEI/10.13039/501100011033 (to AC) and support from Networks of Excellence from MINECO (Nuclear Receptors in Cancer, Metabolism and Inflammation [NuRCaMeIn] SAF2017-90604-REDT to AC. Ministerio de Economía, Industria y Competitividad, Ministerio de Ciencia, Investigación y Universidades, and Agencia Estatal de Investigación (SAF2017-82436-R, RTC2017-6283-1), Centro de Investigación Biomédica en Red en Enfermedades Cardiovasculares (CB16/11/00222), Consorcio de Investigación en Red de la Comunidad de Madrid, S2017/BMD-3686 and Fondo Europeo de Desarrollo Regional (to LB). Ministerio de Ciencia, Investigación y Universidades, and Agencia Estatal de Investigación Proyectos de I+D+i Retos Investigación 2018 (RTI2018-095061-B-I00); TALENTO Grant from Madrid Government, Spain (2017-T1/BMD-5333); Consejería de Ciencia, Universidades e Innovación Comunidad de Madrid, Spain (PEJD-2018-POST/BMD-8900 and PEDJ-2018-AI/BDM-9724) to CMR

    Neutrino physics with the PTOLEMY project: active neutrino properties and the light sterile case

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    The PTOLEMY project aims to develop a scalable design for a Cosmic NeutrinoBackground (CNB) detector, the first of its kind and the only one conceivedthat can look directly at the image of the Universe encoded in neutrinobackground produced in the first second after the Big Bang. The scope of thework for the next three years is to complete the conceptual design of thisdetector and to validate with direct measurements that the non-neutrinobackgrounds are below the expected cosmological signal. In this paper wediscuss in details the theoretical aspects of the experiment and its physicsgoals. In particular, we mainly address three issues. First we discuss thesensitivity of PTOLEMY to the standard neutrino mass scale. We then study theperspectives of the experiment to detect the CNB via neutrino capture ontritium as a function of the neutrino mass scale and the energy resolution ofthe apparatus. Finally, we consider an extra sterile neutrino with mass in theeV range, coupled to the active states via oscillations, which has beenadvocated in view of neutrino oscillation anomalies. This extra state wouldcontribute to the tritium decay spectrum, and its properties, mass and mixingangle, could be studied by analyzing the features in the beta decay electronspectrum

    Electronegative LDL induction of apoptosis in macrophages: Involvement of Nrf2

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    The aim of this study was to determine the apoptotic pathways and mechanisms involved in electronegative LDL [LDL(-)]-induced apoptosis in RAW 264.7 macrophages and the role of Nrf2 in this process. Incubation of RAW 264.7 macrophages with LDL(-) for 24 h resulted in dose-dependent cell death. Activated caspases were shown to be involved in the apoptosis induced by LDL(-); incubation with the broad caspase inhibitor z-VAD prevented apoptosis in LDL(-)-treated cells. CD95 (Fas), CD95 ligand (FasL), CD36 and the tumor necrosis factor (TNF) ligand Tnfsf10 were overexpressed in LDL(-)-treated cells. However, Bax, Bcl-2 and Mcl-1 protein levels remained unchanged after LDL(-) treatment. LDL(-) promoted hyperpolarization of the mitochondrial membrane, elevated reactive oxygen species (ROS) production and translocation of Nrf2 to the nucleus, a process absent in cells treated with native LDL. Elicited peritoneal macrophages from Nrf2-deficient mice exhibited an elevated apoptotic response after challenge with LDL(-), together with an increase in the production of ROS in the absence of alterations in CD36 expression. These results provide evidence that CD36 expression induced by LDL(-) is Nrf2-dependent. Also, it was demonstrated that Nrf2 acts as a compensatory mechanism of LDL(-)-induced apoptosis in macrophages. © 2009 Elsevier B.V. All rights reserved.This study was supported by CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior) and by BFU2008-02161 from MICINN.Peer Reviewe
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