41 research outputs found

    Violation of Boltzmann Equipartition Theorem in Angular Phonon Phase Space Slows down Nanoscale Heat Transfer in Ultrathin Heterofilms

    Get PDF
    Heat transfer through heterointerfaces is intrinsically hampered by a thermal boundary resistance originating from the discontinuity of the elastic properties. Here, we show that with shrinking dimensions the heat flow from an ultrathin epitaxial film through atomically flat interfaces into a single crystalline substrate is significantly reduced due to violation of Boltzmann equipartition theorem in the angular phonon phase space. For films thinner than the phonons mean free path, we find phonons trapped in the film by total internal reflection, thus suppressing heat transfer. Repopulation of those phonon states, which can escape the film through the interface by transmission and refraction, becomes the bottleneck for cooling. The resulting nonequipartition in the angular phonon phase space slows down the cooling by more than a factor of 2 compared to films governed by phonons diffuse scattering. These allow tailoring of the thermal interface conductance via manipulation of the interface

    The ambivalence of losing weight after bariatric surgery

    Get PDF
    This study is grounded in a phenomenological lifeworld perspective. It aims at providing rich descriptions of lived experience of the process of losing weight after obesity surgery. Two women participated in in-depth interviews four times each during the first postoperative year. Based on the women's experiences, a meaning structure—the ambivalence of losing weight after obesity surgery—was identified across the women's processes of change. This consisted of five core themes: movement and activity—freedom but new demands and old restraints; eating habits and digestion—the complexity of change; appearance—smaller, but looser; social relations—stability and change; and being oneself—vulnerability and self-assurance. These core themes changed over time in terms of dominance. The experience of ambivalence is discussed according to a phenomenological perspective of the body as lived experience

    Dilemmas in the process of weight reduction: Exploring how women experience training as a means of losing weight

    Get PDF
    Patients diagnosed with obesity are usually offered group-based behavior interventions which include dietary advice and exercise programs. In particular, high-intensity training—combining weight lifting with aerobic exercising—has been proven effective for losing weight. Moreover, recent studies have shown that persons participating in high-intensity training are more likely to maintain their weight loss compared to persons with lower levels of physical activity. However, most of the research in the field has made use of quantitative methods focusing on the measurable effect of such interventions. Therefore, the aim of this study was to show how the training is experienced from a first-person perspective, namely the patients themselves. Our hope was to shed some new light on the process of weight loss that concerns more than the measurable “impacts” of the training. A qualitative approach was used based on interviews with five women selected from a primary healthcare clinic in Norway. Our results show that experiences of training are connected to the participants' general experience of being overweight. Both relationships to other people and earlier experiences are important for how the training is carried out and perceived. Five themes were identified supporting this line of argument: (1) the gaze of others; (2) a common ground; (3) dependence of close-follow up; (4) bodily discomfort as painful; and (5) aiming for results—an ambivalent experience. The results highlight the importance of finding the proper context and support for each patient's needs

    Atomic Layer Deposition of 2D Metal Dichalcogenides for Electronics, Catalysis, Energy Storage, and Beyond

    Get PDF
    2D transition metal dichalcogenides (TMDCs) are among the most exciting materials of today. Their layered crystal structures result in unique and useful electronic, optical, catalytic, and quantum properties. To realize the technological potential of TMDCs, methods depositing uniform films of controlled thickness at low temperatures in a highly controllable, scalable, and repeatable manner are needed. Atomic layer deposition (ALD) is a chemical gas-phase thin film deposition method capable of meeting these challenges. In this review, the applications evaluated for ALD TMDCs are systematically examined, including electronics and optoelectonics, electrocatalysis and photocatalysis, energy storage, lubrication, plasmonics, solar cells, and photonics. This review focuses on understanding the interplay between ALD precursors and deposition conditions, the resulting film characteristics such as thickness, crystallinity, and morphology, and ultimately device performance. Through rational choice of precursors and conditions, ALD is observed to exhibit potential to meet the varying requirements of widely different applications. Beyond the current state of ALD TMDCs, the future prospects, opportunities, and challenges in different applications are discussed. The authors hope that the review aids in bringing together experts in the fields of ALD, TMDCs, and various applications to eventually realize industrial applications of ALD TMDCs.Peer reviewe

    Translating weight loss into agency: Men’s experiences 5 years after bariatric surgery

    Get PDF
    Fewer men than women with severe obesity undergo bariatric surgery for weight loss, and knowledge about men's situation after surgery, beyond medical status, is lacking. Our aim was to explore men's experiences with life after bariatric surgery from a long-term perspective. We conducted in-depth interviews with 13 men, aged 28–60 years, between 5 and 7 years after surgery. The analysis was inspired by Giorgi's phenomenological method. We found that agency was pivotal for how the men understood themselves and their lives after surgery. Weight loss meant regaining opportunities for living and acting in unrestricted and independent daily lives, yet surgery remained a radical treatment with complex consequences. Turning to surgery had involved conceptualizing their own body size as illness, which the men had resisted doing for years. After surgery, the rapid and major weight loss and the feelings of being exhausted, weak, and helpless were intertwined. The profound intensity of the weight loss process took the men by surprise. Embodying weight loss and change involved an inevitable renegotiating of experiences connected to the large body. Having bariatric surgery was a long-term process that seemed unfinished 5 years after surgery. Restrictions and insecurity connected to health and illness persist, despite successful weight loss and embodied change. Bariatric surgery initiated a complex and long-lasting life-changing process, involving both increased capacity for agency and illness-like experiences

    Surgical suction filter-derived bone graft displays osteogenic miRNA and mRNA patterns

    No full text
    Purpose: Recently, a surgical suction filter device was introduced which aims at generating a suction filter-derived bone grafting substitute (SF-BGS). The osteogenic capacity of this grafting material, however, is unclear. MicroRNAs (miRNAs) and osteogenic mRNAs may influence these processes. The aim of this study was therefore to investigate the quality of the SF-BGS by determining the expression of miRNAs and osteogenic mRNAs. Methods: Samples were collected during non-union surgery. Upon exposure of the intramedullary canal, the surgical vacuum system was fitted with the suction filter device containing collagen complex and synthetic ß-TCP: (Ca3(PO4)2, granule size 5–8 mm, total volume 10 mL (Cerasorb Foam®, Curasan AG, Kleinostheim, Germany). As a control, venous blood was used as in current clinical practice. Samples were snap-frozen and mechanically disrupted. MiRNAs and mRNAs were isolated, transcribed, and pooled for qPCR analysis. Lastly, mRNA targets were determined through in silico target analyses. Results: The study population consisted of seven patients with a posttraumatic long bone non-union (4?; mean age 54 ± 16 years). From the array data, distinct differences in miRNA expression were found between the SF-BGS and control samples. Osteogenic marker genes were overall upregulated in the SF-BGS. Qiagen IPA software identified 1168 mRNA targets for 43 of the overall deregulated miRNAs. Conclusion: This study revealed distinctly deregulated and exclusively expressed osteogenic miRNAs in SF-BGS, as well as overall enhanced osteogenic marker gene expression, as compared to the venous blood control group. These expression profiles were not seen in control samples, indicating that the derived material displays an osteogenic profile. It may therefore be a promising tool to generate a BGS or graft extender when needed
    corecore