2,270 research outputs found

    Characterization of dynamical regimes and entanglement sudden death in a microcavity quantum - dot system

    Full text link
    The relation between the dynamical regimes (weak and strong coupling) and entanglement for a dissipative quantum - dot microcavity system is studied. In the framework of a phenomenological temperature model an analysis in both, temporal (population dynamics) and frequency domain (photoluminescence) is carried out in order to identify the associated dynamical behavior. The Wigner function and concurrence are employed to quantify the entanglement in each regime. We find that sudden death of entanglement is a typical characteristic of the strong coupling regime.Comment: To appear in Journal of Physics: Condensed Matte

    Optimization of the investment casting process

    Get PDF
    Rapid prototyping is an important technique for manufacturing. This work refers to the manufacture of hollow patterns made of polymeric materials by rapid prototyping technologies for its use in the preparation of ceramic molds in the investment casting process. This work is focused on the development of a process for manufacturing patterns different from those that currently exist due to its hollow interior design, allowing its direct use in the fabrication of ceramic molds; avoiding cracking and fracture during the investment casting process, which is an important process for the foundry industry

    Optimiranje postupka kalupljenja u ljevačkom procesu

    Get PDF
    Rapid prototyping is an important technique for manufacturing. This work refers to the manufacture of hollow patterns made of polymeric materials by rapid prototyping technologies for its use in the preparation of ceramic molds in the investment casting process. This work is focused on the development of a process for manufacturing patterns different from those that currently exist due to its hollow interior design, allowing its direct use in the fabrication of ceramic molds; avoiding cracking and fracture during the investment casting process, which is an important process for the foundry industry.Brzo razvijanje prototipa vaĆŸna je proizvodna tehnika. Ovaj se rad odnosi na proizvodnju ĆĄupljih kalupa izrađenih od polimerskih materijala pomoću tehnologija brzog razvijanja prototipa za uporabu u izradi keramičkih modela u postupku kalupljenja ljevačkog procesa. Ovaj rad je usmjeren na razvijanje postupka za proizvodnju kalupa drukčijih od onih kakvi trenutno postoje i to zbog svoje ĆĄuplje unutarnje izvedbe čime se omogućava izravna uporaba u izradi keramičkih modela te se izbje gava pucanje i lom tijekom postupka kalupljenja ljevačkog procesa koji predstavlja vaĆŸan postupak u ljevaoničkoj industriji

    PZT-like structural phase transitions in the BiFeO3-KNbO3 solid solution

    Get PDF
    Despite the high prominence of the perovskites BiFeO3 and KNbO3 the solid solution between the two has received little attention. We report a detailed neutron and synchrotron x-ray powder diffraction, and Raman spectroscopy study which demonstrate an R3c → P4mm → Amm2 series of structural phase transitions similar to that exhibited by the PbZrO3 – PbTiO3 solid solution

    CARGO: a web portal to integrate customized biological information

    Get PDF
    There is a huge quantity of information generated in Life Sciences, and it is dispersed in many databases and repositories. Despite the broad availability of the information, there is a great demand for methods that are able to look for, gather and display distributed data in a standardized and friendly way. CARGO (Cancer And Related Genes Online) is a configurable biological web portal designed as a tool to facilitate, integrate and visualize results from Internet resources, independently of their native format or access method. Through the use of small agents, called widgets, supported by a Rich Internet Application (RIA) paradigm based on AJAX, CARGO provides pieces of minimal, relevant and descriptive biological information. The tool is designed to be used by experimental biologists with no training in bioinformatics. In the current state, the system presents a list of human cancer genes. Available at http://cargo.bioinfo.cnio.e

    Assessing depleted uranium (DU) contamination of soil, plants and earthworms at UK weapons testing sites

    Get PDF
    Depleted uranium (DU) weapons testing programmes have been conducted at two locations within the UK. An investigation was therefore carried out to assess the extent of any environmental contamination arising from these test programmes using both alpha spectrometry and mass spectrometry techniques. Uranium isotopic signatures indicative of DU contamination were observed in soil, plant and earthworm samples collected in the immediate vicinity of test firing points and targets, but contamination was found to be localised to these areas. The paper demonstrates the superiority of the 235U:238U ratio over the 234U:238U ratio for identifying and quantifying DU contamination in environmental samples and also describes the respective circumstances under which alpha spectrometry or mass spectrometry may be the more appropriate analytical tool

    An Exploratory Study of Healing Circles as a Strategy to Facilitate Resilience in an Undocumented Community

    Get PDF
    Within the United States, the COVID-19 pandemic highlighted critical inequalities affecting undocumented communities and resulting in particularly heightened stress for members of these communities. In addition to the stress associated with COVID-19, immigrants in the United States were more than ever subjected to a hostile antiimmigrant climate under Trump’s administration. Given this compounded stress, the impact of the pandemic on mental health is likely to be disproportionately experienced by undocumented immigrants. In response, a group of psychologists partnered with a leading immigrant rights advocacy organization and formed a reciprocal collaboration to support undocumented communities. A major focus of the collaboration is to foster learning, supporting members of the immigrant community to contribute to their own well-being and others in the community. Accordingly, the collaborative developed and delivered a web-based mental health education session to the immigrant community and to practitioners serving this population. The session presented the use of healing circles as a strength-based approach to building resilience and also sought feedback regarding specific features of healing circles that can enhance their effectiveness in managing distress. Survey data and qualitative findings from this study show that those who participated in the web-based program perceived the session as validating and informative. Findings also underscored the need for creating safe spaces for community members to be vulnerable about their lived experiences while promoting ownership of their narratives. We discuss practical implications pertaining to the development and facilitation of social support groups for immigrants led by nonspecialist community members trained for this role. Impact Statement We describe a reciprocal collaboration between psychologists and an immigrant-led advocacy organization for the purposes of supporting undocumented immigrants in tailoring culturally congruent therapeutic approaches for fostering resilience as they face multiple stressors due to interlocking crises, such as the COVID-19 pandemic and antiimmigrant policies. The collaboration led to the development and delivery of a web-based session that provided immigrant community members and practitioners with recommendations for facilitating healing circles as a strength-based and culturally responsive approach to fostering peer-led social support during stressful times. Findings highlight the need for creating such safe spaces for community members to be vulnerable about their lived experiences and feel validated

    Chia (Salvia hispanica L.) products as ingredients for reformulating frankfurters: Effects on quality properties and shelf-life

    Get PDF
    Several strategies were examined for incorporating chia products (seeds, flour and a coproduct from cold-press oil extraction) in frankfurters. The nutritional composition, technological properties and sensory attributes of the resulting products were studied in relation to the formulation used and, lipid oxidation, pH, residual nitrite level and microbiological properties were evaluated during chilled storage. Application of these chia products (3%) was seen to enhance the nutritional composition of frankfurters, without adversely affecting the technological properties of the final product. In general, although differences were detected in the sensory attributes of the frankfurters reformulated with chia products (most of them when chia coproduct was added), all of them were judged acceptable. Besides the quality aspects, these reformulation strategies had beneficial effects on some technological properties during chilled storage: better resistance to oxidation (controlling the TBARS increase during storage) and lower residual nitrite levels than control (both effects presumably because the chia polyphenols content) and no effect on microbiological safet

    Antioxidant and Anti-Inflammatory Strategies Based on the Potentiation of Glutathione Peroxidase Activity Prevent Endothelial Dysfunction in Chronic Kidney Disease

    Get PDF
    BACKGROUND/AIMS: Accelerated atherosclerosis in chronic kidney disease (CKD) is preceded by endothelial dysfunction (ED), which exhibits a proinflammatory and prothrombotic phenotype and enhanced oxidative stress. In this study, the effect of several compounds with anti-inflammatory and/or antioxidant properties on uremia-induced endothelial dysfunction has been evaluated in an in vitro model. METHODS: Endothelial cells (ECs) were exposed to sera from uremic patients in the absence and presence of the flavonoids apigenin, genistein and quercetin, the antioxidant enzyme mimetics (AEM) ebselen (glutathione peroxidase mimetic), EUK-134 and EUK-118 (both superoxide dismutase mimetics), and the pharmacological drug N-acetylcysteine (NAC). We explored changes in the expression of adhesion receptors on the cell surface, by immunofluorescence, the production of radical oxygen species (ROS), by fluorescence detection, and the activation of signaling proteins related to inflammation, by both a phosphospecific antibody cell-based ELISA and immunoblotting techniques. RESULTS: Uremic media induced a significantly increased expression of ICAM-1, overproduction of radical oxygen species (ROS) and activation of p38 mitogen activated protein kinase (p38MAPK) and Nuclear Factor kB (NFkB) in ECs. Quercetin, the AEM and NAC showed a significant inhibitory effect on both ICAM-1 expression and ROS generation (p<0.05). All the compounds reduced p38MAPK activation, but only the AEM, especially ebselen, and NAC, both potentiating the glutathione peroxidase pathway, also inhibited NFkB activation. These two compounds were capable of increasing endothelial glutathione levels, especially in response to uremia. CONCLUSION: Our results indicate that the potentiation of the antioxidant pathways can be an effective strategy to improve endothelial dysfunction in uremia and a potential target to reduce the cardiovascular risk in this population
    • 

    corecore