239 research outputs found

    Three interacting atoms in a one-dimensional trap: A benchmark system for computational approaches

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    We provide an accurate calculation of the energy spectrum of three atoms interacting through a contact force in a one-dimensional harmonic trap, considering both spinful fermions and spinless bosons. We use fermionic energies as a benchmark for exact-diagonalization technique (also known as full configuration interaction), which is found to slowly converge in the case of strong interatomic attraction.Comment: To appear in Journal of Physics B: Atomic, Molecular and Optical Physic

    Pairing of few Fermi atoms in one dimension

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    We study a few Fermi atoms interacting through attractive contact forces in a one-dimensional trap by means of numerical exact diagonalization. From the combined analysis of energies and wave functions of correlated ground and excited states we find evidence of BCS-like pairing even for very few atoms. For moderate interaction strength, we reproduce the even-odd oscillation of the separation energy observed in [G. Zuern, A. N. Wenz, S. Murmann, A. Bergschneider, T. Lompe, and S. Jochim, Phys. Rev. Lett. 111, 175302 (2013)]. For strong interatomic attraction the arrangement of dimers in the trap differs from the homogeneous case as a consequence of Pauli blockade in real space.Comment: Major revision to appear in Physical Review

    Reconstruction of old radical cavities and long-term results

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    Various techniques and materials have been proposed to deal with the problems that concern radical cavities, such as recurrence of the inflammatory process, the need for regular medication, and social inconvenience (eg, inability to practice water sports, working in an adverse enviroment). This article provides a detailed report of the results of revalidation of old radical cavities using hydroxyapatite granules as a filling. The material was incorporated with fibrin adhesive to fill the mastoid cavity and was covered with a sheet of bone pate sealant. Twenty-eight patients with chronic discharging old radical cavities were selected for this study (mean follow-up 11.4 years; range 10-14 years). At the 6-month follow-up, grafting was successful in 25 patients, whereas the functional outcomes showed an air-bone gap below 30 dB in 18 patients. No postoperative sensorineural hearing loss was observed. The long-term follow-up demonstrated a slight worsening of the initial findings; four other patients had reperforation of the tympanic membrane, and hearing deteriorated in five patients to above 30 dB air-bone gap. These results could be a consequence of an alteration in the function of the eustachian tube and of the severity of the preoperative pathologic processes

    Neuroprotective Strategies in Neurodegenerative Disorders

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    Neurodegeneration is the progressive loss of the structure or the function of the neurons. Indeed, the dopaminergic function in Parkinson’s disease (PD) is strongly damaged. Currently, L-DOPA is the most effective treatment for PD. However, the wearing off and on-off phenomena represent a limit of this therapy. Moreover, events like a stroke can cause severe impairments and neural death. In this context, the sirtuin family has shown to have a significant influence on the extent of neuronal death. In this work, firstly, we highlighted the ability of sulforaphane, an isothiocyanate, in counteracting and preventing the neurotoxicity induced by L-DOPA. This effect is mediated by the NRF2 pathway through the increase of cellular antioxidant defenses. Secondly, in C. elegans, we found that knock-out of mitochondrial sirtuin sir-2.3, homologous to mammalian SIRT4, is protective in both chemical ischemia and hyperactive channel induced necrosis. Furthermore, the block of glycolysis enhances the protective effect of sir-2.3 knock-out both in vivo and in culture, suggesting that this occurs independently of the insulin/IGF pathway. Analysis of ROS in sir-2.3 knock-out reveals that ROS become elevated in this mutant under dietary deprivation (DD) and early on in dietary deprived animals under ischemic conditions, suggesting that mitohormetic elevation of ROS is operative in this mutant. In conclusion, this work suggests novel pathways that can be targeted for the design of therapies aimed at protecting neurons from age linked damages

    Eclogites, jades and other HP-metaophiolites employed for prehistoric polished stone implements in Italy and Europe

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    Prehistoric polished stone tools are now fairly well-known from a petrographic point of view in Northern Italy. Many more than one thousand implements sampled from the most important sites and collections (axes, adzes, chisels, some ornaments and various tools fragments), have been analysed. These artefacts were commonly employed from the Neolithic period onwards for working wood and cutting the forest trees. Surface optical observations, density, thin sections, XRD, microprobe analyses and bulk chemistry have been employed, alone or in combination, for petrographic study oriented to archaeometric interpretation. Alpine eclogites, jades (Na-pyroxenites) and other minor HP (High Pressure) metaophiolites dominate the polished stone lithology of Northern Italy, being at least 70% and often surpassing 90% of stone materials in single sites. Petrographic, geochemical, minerochemical, textural data of the studied rocks are described and discussed in some detail. A number of new definitions are introduced. The provenance of the raw material is identified as being NW Italy, essentially Piedmont and Liguria. These regions represent one of the few geological zones in the world where alpine eclogites and jades occur, both as primary outcrops in the High Alps, alluvial and morainic deposits along the valleys, and Oligocene conglomerates in the Northwestern Apennines. The dominance of eclogites and jades among the prehistoric polished stone tools represents a lithic selection of cultural significance. This selection seems to be justified by litho-technological (best mix of hardness, toughness and density) and aesthetic (fine green colours, translucency) reasons, which caused the exclusion of other, elsewhere common, lithologies. The remarkable presence of jade and alpine eclogite lithologies among the Western and rarely Central European axe blades (mostly status symbol or ceremonial axes) gives evidence of a relevant long distance exportation of HP metaophiolite materials from NW Italy to France, Germany, Benelux, Great Britain, etc., up to1000-1500 km far from the source areas. The still unsystematic petrographic knowledge of the HP-metaophiolitic stones of the axe blades in Europe, as well as in the Italian Peninsula, allows only a preliminary comparison with the better known Northern Italian implements

    Constraints on modified gravity from the BOSS galaxy survey

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    We develop a pipeline to set new constraints on scale-independent modified gravity, from the galaxy power spectrum in redshift space of BOSS DR12. The latter is modelled using the effective field theory of large-scale structure up to 1-loop order in perturbation theory. We test our pipeline on synthetic and simulated data, to assess systematic biases on the inferred cosmological parameters due to marginalization and theoretical errors, and we apply it to the normal branch of the DGP model with a Λ\LambdaCDM background. We observe biased posteriors due to the strong degeneracy between the nDGP parameter Ωrc\Omega_{\rm rc} and the primordial amplitude of fluctuations AsA_s. Fixing the latter to the Planck central value, we obtain Ωrc0.2\Omega_{\rm rc}\lesssim 0.2 at 95%\% C.L. We also discuss a procedure to alleviate the prior dependence of this bound.Comment: 27 pages, 9 figure

    Second-harmonic generation sensitivity to transmembrane potential in normal and tumor cells.

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    Second-harmonic generation (SHG) is emerging as a powerful tool for the optical measurement of transmembrane potential in live cells with high sensitivity and temporal resolution. Using a patch clamp, we characterize the sensitivity of the SHG signal to transmembrane potential for the RH 237 dye in various normal and tumor cell types. SHG sensitivity shows a significant dependence on the type of cell, ranging from 10 to 17% per 100 mV. Furthermore, in the samples studied, tumor cell lines display a higher sensitivity compared to normal cells. In particular, the SHG sensitivity increases in the cell line Balb/c3T3 by the transformation induced with SV40 infection of the cells. We also demonstrate that fluorescent labeling of the membrane with RH 237 at the concentration used for SHG measurements does not induce any measurable alteration in the electrophysiological properties of the cells investigated. Therefore, SHG is suitable for the investigation of outstanding questions in electrophysiology and neurobiology

    Comparison of Adaptive Neuroprotective Mechanisms of Sulforaphane and its Interconversion Product Erucin in in Vitro and in Vivo Models of Parkinson's Disease

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    Several studies suggest that an increase of glutathione (GSH) through activation of the transcriptional nuclear factor (erythroid-derived 2)-like 2 (Nrf2) in the dopaminergic neurons may be a promising neuroprotective strategy in Parkinson's disease (PD). Among Nrf2 activators, isothiocyanate sulforaphane (SFN), derived from precursor glucosinolate present in Brassica vegetables, has gained attention as a potential neuroprotective compound. Bioavailability studies also suggest the contribution of SFN metabolites, including erucin (ERN), to the neuroprotective effects of SFN. Therefore, we compared the in vitro neuroprotective effects of SFN and ERN at the same dose level (5 \u3bcM) and oxidative treatment with 6-hydroxydopamine (6-OHDA) in SH-SY5Y cells. The pretreatment of SH-SY5Y cells with SFN recorded a higher (p < 0.05) active nuclear Nrf2 protein (12.0 \ub1 0.4 vs 8.0 \ub1 0.2 fold increase), mRNA Nrf2 (2.0 \ub1 0.3 vs 1.4 \ub1 0.1 fold increase), total GSH (384.0 \ub1 9.0 vs 256.0 \ub1 8.0 \u3bcM) levels, and resistance to neuronal apoptosis elicited by 6-OHDA compared to ERN. By contrast, the simultaneous treatment of SH-SY5Y cells with either SFN or ERN and 6-OHDA recorded similar neuroprotective effects with both the isothiocyanates (Nrf2 protein 2.2 \ub1 0.2 vs 2.1 \ub1 0.1 and mRNA Nrf2 2.1 \ub1 0.3 vs 1.9 \ub1 0.2 fold increase; total GSH 384.0 \ub1 4.8 vs 352.0 \ub1 6.4 \u3bcM). Finally, in vitro finding was confirmed in a 6-OHDA-PD mouse model. The metabolic oxidation of ERN to SFN could account for their similar neuroprotective effects in vivo, raising the possibility of using vegetables containing a precursor of ERN for systemic antioxidant benefits in a similar manner to SFN

    Isolation and Identification of Cancer Stem-Like Cells in Adenocarcinoma and Squamous Cell Carcinoma of the Lung: A Pilot Study

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    Background: Lung cancer stem cells (CSCs) share many characteristics with normal stem cells, such as self-renewal and multipotentiality. High expression of aldehyde dehydrogenase (ALDH) has been detected in many tumors, particularly in the CSC compartment, and it plays an important role in tumor proliferation, metastasis, and drug resistance. CD44 is commonly used as a cell surface marker of cancer stem-like cells in epithelial tumors. The aim of this study was to isolate and analyze cancer stem-like cells from surgically removed specimens to compare lung adenocarcinoma (ADENO) and squamous (SQUAMO) cell carcinoma. Methods: The ALDEFLUOR assay was used to identify and sort ALDHhigh and ALDHlow human lung cancer cells following tissue digestion. Fluorescence-activated cell sorting analysis for CD44 was performed with tumor cells. Quantitative real-time PCR was performed to assess the expression of SOX2 and NANOG as stemness markers. ALDH1A1 expression was additionally determined by immunohistochemistry. Anchorage-independent ALDHhigh cell growth was also evaluated. ALDHhigh ADENO and SQUAMO cells were cultured to analyze spheroid formation. Results: All specimens contained 0.5–12.5% ALDHhigh cells with 3.8–18.9% CD44-positive cells. SOX2 and NANOG relative expression in ALDHhigh compared to ALDHlow cells in ADENO and SQUAMO was analyzed and compared between the histotypes. Immunohistochemistry confirmed the presence of ALDH1A1 in the sections. SOX2 and NANOG were expressed at higher levels in the ALDHhigh subpopulation than in the ALDHlow subpopulation only in ADENO cells, and the opposite result was seen in SQUAMO cells. In vitro functional assays demonstrated that ALDHhigh cells exhibited migration capacity with distinct behaviors between ALDHhigh spheres in ADENO vs. SQUAMO samples. Conclusions: Our results highlight the importance of a better characterization of cancer stem-like cells in ADENO and SQUAMO histotypes. This may suggest new differential approaches for prognostic and therapeutic purposes in patients with non-small-cell lung cancer
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