1,318 research outputs found

    Observation of oscillatory relaxation in the Sn-terminated surface of epitaxial rock-salt SnSe {111}\{111\} topological crystalline insulator

    Full text link
    Topological crystalline insulators have been recently predicted and observed in rock-salt structure SnSe {111}\{111\} thin films. Previous studies have suggested that the Se-terminated surface of this thin film with hydrogen passivation, has a reduced surface energy and is thus a preferred configuration. In this paper, synchrotron-based angle-resolved photoemission spectroscopy, along with density functional theory calculations, are used to demonstrate conclusively that a rock-salt SnSe {111}\{111\} thin film epitaxially-grown on \ce{Bi2Se3} has a stable Sn-terminated surface. These observations are supported by low energy electron diffraction (LEED) intensity-voltage measurements and dynamical LEED calculations, which further show that the Sn-terminated SnSe {111}\{111\} thin film has undergone a surface structural relaxation of the interlayer spacing between the Sn and Se atomic planes. In sharp contrast to the Se-terminated counterpart, the observed Dirac surface state in the Sn-terminated SnSe {111}\{111\} thin film is shown to yield a high Fermi velocity, 0.50×1060.50\times10^6m/s, which suggests a potential mechanism of engineering the Dirac surface state of topological materials by tuning the surface configuration.Comment: 12 pages, 13 figures, supplementary materials include

    Cadmium accumulation and interactions with zinc, copper, and manganese, analysed by ICP-MS in a long-term Caco-2 TC7 cell model

    Get PDF
    The influence of long-term exposure to cadmium (Cd) on essential minerals was investigated using a Caco-2 TC7 cells and a multi-analytical tool: microwave digestion and inductively coupled plasma mass spectrometry. Intracellular levels, effects on cadmium accumulation, distribution, and reference concentration ranges of the following elements were determined: Na, Mg, Ca, Cr, Fe, Mn, Co, Ni, Cu, Zn, Mo, and Cd. Results showed that Caco-2 TC7 cells incubated long-term with cadmium concentrations ranging from 0 to 10 lmol Cd/l for 5 weeks exhibited a significant increase in cadmium accumulation. Furthermore, this accumulation was more marked in cells exposed long-term to cadmium compared with controls, and that this exposure resulted in a significant accumulation of copper and zinc but not of the other elements measured. Interactions of Cd with three elements: zinc, copper, and manganese were particularly studied. Exposed to 30 lmol/l of the element, manganese showed the highest inhibition and copper the lowest on cadmium intracellular accumulation but Zn, Cu, and Mn behave differently in terms of their mutual competition with Cd. Indeed, increasing cadmium in the culture medium resulted in a gradual and significant increase in the accumulation of zinc. There was a significant decrease in manganese from 5 lmol Cd/l exposure, and no variation was observed with copper. Abbreviation: AAS – Atomic absorption spectrometry; CRM– Certified reference material; PBS – Phosphate buffered saline without calcium and magnesium; DMEM – Dubelcco’s modified Eagle’s medium

    Creating a Stir: The role of Word of Mouth in Reputation Management in the Context of Festivals

    Get PDF
    This qualitative case study examines the role of word of mouth (WOM) in reputation management in the context of networked festival productions. Particularly, it explores the ways in which WOM marketing (WOMM) is employed in festival marketing and brand-building. The paper links reputation and WOM to the concept of cultural branding with the aim of providing a framework for analysing how a festival's reputation shapes the creation of a culturally meaningful message. The empirical analysis is based on a multiple-case study involving three Finnish festivals hosted in the city of Pori: the Porispere Festival, the International Pori Jazz Festival and the International Lain�uojattomat Theatre Festival. The cases represent festivals of different sizes and varying organisational structure, content and life cycle. The findings indicate that the meaning and use of WOMM vary depending on key constitutive differences that affect the nature of the festivals? reputation and brand-building processes. Although the importance of external and internal stakeholders in these processes is evident, it seems that when the power of networks is recognised as crucial for festivals, WOM has a leveraging role in reputation management and brand-building. In these processes, the value of the festival leader's persona becomes crucial

    Luxury fashion brands: factors influencing young female consumers' luxury fashion purchasing in Taiwan

    Get PDF
    Purpose - Against the background of increasing consumption of luxury fashion brands by young female consumers in Asian countries, this paper offers insights into the consumption motives and purchasing behaviour of that market segment in Taiwan. Design/methodology/approach - Analysis of data collected using face-to-face semi-structured interviews with twenty-three 18-32 year-old fashion-conscious females was completed and new empirical insights are offered. Findings - The study found a high level of involvement in the world of luxury fashion retailing. Asian consumers devoured media commentary, drew inspiration from female celebrities, and treated information-seeking and discussion of luxury fashion brands with friends as a serious and enjoyable pursuit. The social status conferred by expensive fashion wear motivated them to spend on luxury brands even if their discretionary income was limited. Potential guilt in so doing was assuaged by rationalising that the quality was good and the purchase would be long lasting. Marketers targeting this valuable segment should communicate appeals to an aspirational lifestyle in traditional and social media, effective at reaching young women. Originality/value - The study reported in this article contributes to the limited published research into the luxury marketing sector in Asia by examining the buying behaviour of female Strawberry Generation consumers in Taiwan. It is the first to research and investigate the meanings attached to luxury by these individuals in the collectivist culture of Taiwan, as well as their motivations, and the factors influencing their purchase of luxury fashions. The study thus contributes with new knowledge to the buying of luxury fashion products by young female Taiwanese consumers, which may be extended to other collectivist cultures in Asia

    Analytical protocols for separation and electron microscopy of nanoparticles interacting with bacterial cells

    Get PDF
    An important step toward understanding interactions between nanoparticles (NPs) and bacteria is the ability to directly observe NPs interacting with bacterial cells. NPbacteria mixtures typical in nanomedicine, however, are not yet amendable for direct imaging in solution. Instead, evidence of NPcell interactions must be preserved in derivative (usually dried) samples to be subsequently revealed in high-resolution images, e.g., via scanning electron microscopy (SEM). Here, this concept is realized for a mixed suspension of model NPs and Staphylococcus aureus bacteria. First, protocols for analyzing the relative colloidal stabilities of NPs and bacteria are developed and validated based on systematic centrifugation and comparison of colony forming unit (CFU) counting and optical density (OD) measurements. Rate-dependence of centrifugation efficiency for each component suggests differential sedimentation at a specific predicted rate as an effective method for removing free NPs after co-incubation; the remaining fraction comprises bacteria with any associated NPs and can be examined, e.g., by SEM, for evidence of NPbacteria interactions. These analytical protocols, validated by systematic control experiments and high-resolution SEM imaging, should be generally applicable for investigating NPbacteria interactions.financial support from the following sources: grant SFRH/BPD/47693/2008 from the Portuguese Foundation for Science and Technology (FCT); FCT Strategic Project PEst-OE/EQB/LA0023/2013; project “BioHealth Biotechnology and Bioengineering approaches to improve health quality”, Ref. NORTE-07-0124-FEDER-000027, cofunded by the Programa Operacional Regional do Norte (ON.2−O Novo Norte), QREN, FEDER; project “Consolidating Research Expertise and Resources on Cellular and Molecular Biotechnology at CEB/IBB”, ref. FCOMP-01-0124-FEDER- 027462

    Pyrrolidine dithiocarbamate administered during ex-vivo lung perfusion promotes rehabilitation of injured donor rat lungs obtained after prolonged warm ischemia.

    Get PDF
    Damaged lung grafts obtained after circulatory death (DCD lungs) and warm ischemia may be at high risk of reperfusion injury after transplantation. Such lungs could be pharmacologically reconditioned using ex-vivo lung perfusion (EVLP). Since acute inflammation related to the activation of nuclear factor kappaB (NF-κB) is instrumental in lung reperfusion injury, we hypothesized that DCD lungs might be treated during EVLP by pyrrolidine dithiocarbamate (PDTC), an inhibitor of NF-κB. Rat lungs exposed to 1h warm ischemia and 2 h cold ischemia were subjected to EVLP during 4h, in absence (CTRL group, N = 6) or in presence of PDTC (2.5g/L, PDTC group, N = 6). Static pulmonary compliance (SPC), peak airway pressure (PAWP), pulmonary vascular resistance (PVR), and oxygenation capacity were determined during EVLP. After EVLP, we measured the weight gain of the heart-lung block (edema), and the concentration of LDH (cell damage), proteins (permeability edema) and of the cytokines IL-6, TNF-α and CINC-1 in bronchoalveolar lavage (BAL), and we evaluated NF-κB activation by the degree of phosphorylation and degradation of its inhibitor IκBα in lung tissue. In CTRL, we found significant NF-κB activation, lung edema, and a massive release of LDH, proteins and cytokines. SPC significantly decreased, PAWP and PVR increased, while oxygenation tended to decrease. Treatment with PDTC during EVLP inhibited NF-κB activation, did not influence LDH release, but markedly reduced lung edema and protein concentration in BAL, suppressed TNFα and IL-6 release, and abrogated the changes in SPC, PAWP and PVR, with unchanged oxygenation. In conclusion, suppression of innate immune activation during EVLP using the NF-κB inhibitor PDTC promotes significant improvement of damaged rat DCD lungs. Future studies will determine if such rehabilitated lungs are suitable for in vivo transplantation

    Psychotherapy in historical perspective

    Get PDF
    This article will briefly explore some of the ways in which the past has been used as a means to talk about psychotherapy as a practice and as a profession, its impact on individuals and society, and the ethical debates at stake. It will show how, despite the multiple and competing claims about psychotherapy’s history and its meanings, historians themselves have, to a large degree, not attended to the intellectual and cultural development of many therapeutic approaches. This absence has the potential consequence of implying that therapies have emerged as value-free techniques, outside of a social, economic and political context. The relative neglect of psychotherapy, by contrast with the attention historians have paid to other professions, particularly psychiatry, has also underplayed its societal impact. This article will foreground some of the instances where psychotherapy has become an object of emerging historical interest, including the new research that forms the substance of this special issue of History of the Human Sciences
    corecore