Inverse Finite Element Approach to Identify the Post-Necking Hardening Behavior of Polyamide 12 under Uniaxial Tension.

Finite-element (FE) simulations that go beyond the linear elastic limit of materials can aid the development of polymeric products such as stretch blow molded angioplasty balloons. The FE model requires the input of an appropriate elastoplastic material model. Up to the onset of necking, the identification of the hardening curve is well established. Subsequently, additional information such as the cross-section and the triaxial stress state inside the specimen is required. The present study aims to inversely identify the post-necking hardening behavior of the semi-crystalline polymer polyamide 12 (PA12) at different temperatures. Our approach uses structural FE simulations of a dog-bone tensile specimen in LS-DYNA with mesh sizes of 1 mm and 2 mm, respectively. The FE simulations are coupled with an optimization routine defined in LS-OPT to identify material properties matching the experimental behavior. A Von Mises yield criterion coupled with a user-defined hardening curve (HC) were considered. Up to the beginning of necking, the Hockett-Sherby hardening law achieved the best fit to the experimental HC. To fit the entire HC until fracture, an extension of the Hockett-Sherby law with power-law functions achieved an excellent fit. Comparing the simulation and the experiment, the following coefficient of determination R2 could be achieved: Group I: R2 > 0.9743; Group II: R2 > 0.9653; Group III: R2 > 0.9927. Using an inverse approach, we were able to determine the deformation behavior of PA12 under uniaxial tension for different temperatures and mathematically describe the HC

Masterpieces of Swiss Entrepreneurship

This open access book focuses on Switzerland-based medium-sized companies with a longstanding export tradition and a proven dominance in global niche markets. Based upon in-depth documentation and analysis of 36 Swiss companies over their entire history, an expert team of authors presents several parallels in the pathways and success factors which allowed these firms to become dominant and operate from a high-cost location such as Switzerland. The book enhances these insights by providing detailed company profiles documenting the company history, development, and how their relevant global niche positions were reached. Readers will benefit from these profiles as they compile a diverse selection of industries, mainly active within the B2B sector, with mostly mature companies (60 years to older than 100 years since founding) and different types of ownership structures including family firms. ‘Masterpieces of Swiss Entrepreneurship’ brings unique learning opportunities to owners and leaders of SMEs in Switzerland and elsewhere. Findings are based on detailed bottom-up research of 36 companies -- without any preconceived notions. The book is both conceptual and practical. It fosters understanding for different choices in development pathways and management practices. Matti Alahuhta, Chairman DevCo Partners, ex-CEO Kone, Board member of several global listed companies, Helsinki, Finland Start-up entrepreneurs need proven models from industry which demonstrate the various paths to success. “Masterpieces of Swiss Entrepreneurship” provides deep insights highlighting these models and the important trade-offs entrepreneurial teams must consider when choosing the path of high growth or of maximum control, as they are often mutually exclusive. Gina Domanig, Managing Partner, Emerald Technology Ventures, Zurich

Masterpieces of Swiss entrepreneurship : Swiss SMEs competing in global markets

This open access book focuses on Switzerland-based medium-sized companies with a longstanding export tradition and a proven dominance in global niche markets. Based upon in-depth documentation and analysis of 36 Swiss companies over their entire history, an expert team of authors presents several parallels in the pathways and success factors which allowed these firms to become dominant and operate from a high-cost location such as Switzerland. The book enhances these insights by providing detailed company profiles documenting the company history, development, and how their relevant global niche positions were reached. Readers will benefit from these profiles as they compile a diverse selection of industries, mainly active within the B2B sector, with mostly mature companies (60 years to older than 100 years since founding) and different types of ownership structures including family firms. ‘Masterpieces of Swiss Entrepreneurship’ brings unique learning opportunities to owners and leaders of SMEs in Switzerland and elsewhere. Findings are based on detailed bottom-up research of 36 companies -- without any preconceived notions. The book is both conceptual and practical. It fosters understanding for different choices in development pathways and management practices. Matti Alahuhta, Chairman DevCo Partners, ex-CEO Kone, Board member of several global listed companies, Helsinki, Finland Start-up entrepreneurs need proven models from industry which demonstrate the various paths to success. “Masterpieces of Swiss Entrepreneurship” provides deep insights highlighting these models and the important trade-offs entrepreneurial teams must consider when choosing the path of high growth or of maximum control, as they are often mutually exclusive

Mechanical testing and comparison of porcine tissue, silicones and 3D-printed materials for cardiovascular phantoms

Background: Cardiovascular phantoms for patient education, pre-operative planning, surgical training, haemodynamic simulation, and device testing may help improve patient care. However, currently used materials may have different mechanical properties compared to biological tissue.Methods/Aim: The aim of this study was to investigate the mechanical properties of 3D-printing and silicone materials in comparison to biological cardiovascular tissues. Uniaxial cyclic tension testing was performed using dumbbell samples from porcine tissue (aorta, pulmonary artery, right and left ventricle). Flexible testing materials included 15 silicone (mixtures) and three 3D-printing materials. The modulus of elasticity was calculated for different deformation ranges.Results: The modulus of elasticity (0%–60%) for the aorta ranged from 0.16 to 0.18 N/mm2, for the pulmonary artery from 0.07 to 0.09 N/mm2, and for the right ventricle as well as the left ventricle short-axis from 0.1 to 0.16 N/mm2. For silicones the range of modulus of elasticity was 0.02–1.16 N/mm2, and for the 3D-printed materials from 0.85 to 1.02 N/mm2. The stress-strain curves of all tissues showed a non-linear behaviour in the cyclic tensile testing, with a distinct toe region, followed by exponential strain hardening behaviour towards the peak elongation. The vessel samples showed a more linear behaviour comparted to myocardial samples. The silicones and 3D printing materials exhibited near-linearity at higher strain ranges, with a decrease in stiffness following the initial deformation. All samples showed a deviation between the loading and unloading curves (hysteresis), and a reduction in peak force over the first few cycles (adaptation effect) at constant deformation.Conclusion: The modulus of elasticity of silicone mixtures is more in agreement to porcine cardiovascular tissues than 3D-printed materials. All synthetic materials showed an almost linear behaviour in the mechanical testing compared to the non-linear behaviour of the biological tissues, probably due to fibre recruitment mechanism in the latter

Genossenschaftliche Identität und Wachstum mit sozial-ökologischem Imperativ: Eine empirische Befragung der Schweizer Bevölkerung mit Daten von 2011 und 2016.

Diese repräsentative empirische Untersuchung in der Schweizer Bevölkerung untersucht Grundfragen zu genossenschaftlicher Identität und genossenschaftlichem Wachstum. Vor dem Hintergrund einer wachstumskritischen Stimmung in der Schweizer Bevölkerung wird das genossenschaftliche Wachstum positiver gesehen, sie unterliegen jedoch dem "sozial-ökologischen Verhaltensimperativ", d.h. nur als gesellschaftlich positiv erlebten Unternehmen wird Wachstum zugestanden, andere sollen eher schrumpfen. Dabei profitiert die Rechtsform Genossenschaft in den Augen der Bevölkerung von einem sehr hohen, zeitlich stabilen Vertrauen. Die konstituierenden Merkmale der Genossenschaft ("DNA Elemente") werden ebenfalls, im Zeitverlauf nahezu unverändert, als positiv erlebt

Photochemically-Mediated Inflammation and Cross-Presentation of Mycobacterium bovis BCG Proteins Stimulates Strong CD4 and CD8 T-Cell Responses in Mice

Conventional vaccines are very efficient in the prevention of bacterial infections caused by extracellular pathogens due to effective stimulation of pathogen-specific antibodies. In contrast, considering that intracellular surveillance by antibodies is not possible, they are typically less effective in preventing or treating infections caused by intracellular pathogens such as Mycobacterium tuberculosis. The objective of the current study was to use so-called photochemical internalization (PCI) to deliver a live bacterial vaccine to the cytosol of antigen-presenting cells (APCs) for the purpose of stimulating major histocompatibility complex (MHC) I-restricted CD8 T-cell responses. For this purpose, Mycobacterium bovis BCG (BCG) was combined with the photosensitiser tetraphenyl chlorine disulfonate (TPCS2a) and injected intradermally into mice. TPCS2a was then activated by illumination of the injection site with light of defined energy. Antigen-specific CD4 and CD8 T-cell responses were monitored in blood, spleen, and lymph nodes at different time points thereafter using flow cytometry, ELISA and ELISPOT. Finally, APCs were infected and PCI-treated in vitro for analysis of their activation of T cells in vitro or in vivo after autologous vaccination of mice. Combination of BCG with PCI induced stronger BCG-specific CD4 and CD8 T-cell responses than treatment with BCG only or with BCG and TPCS2a without light. The overall T-cell responses were multifunctional as characterized by the production of IFN-γ, TNF-α, IL-2 and IL-17. Importantly, PCI induced cross-presentation of BCG proteins for stimulation of antigen-specific CD8 T-cells that were particularly producing IFN-γ and TNF-α. PCI further facilitated antigen presentation by causing up-regulation of MHC and co-stimulatory proteins on the surface of APCs as well as their production of TNF-α and IL-1β in vivo. Furthermore, PCI-based vaccination also caused local inflammation at the site of vaccination, showing strong infiltration of immune cells, which could contribute to the stimulation of antigen-specific immune responses. This study is the first to demonstrate that a live microbial vaccine can be combined with a photochemical compound and light for cross presentation of antigens to CD8 T cells. Moreover, the results revealed that PCI treatment strongly improved the immunogenicity of M. bovis BCG. Keywords: PCI facilitates BCG vaccination; T cells; cross-presentation; photochemical internalization; tuberculosis; vaccine

Forum: Visual Studies—The Art Historians’ View

Description to be added.Cannot be left empt

Analysis of Outcomes in Ischemic vs Nonischemic Cardiomyopathy in Patients With Atrial Fibrillation A Report From the GARFIELD-AF Registry

IMPORTANCE Congestive heart failure (CHF) is commonly associated with nonvalvular atrial fibrillation (AF), and their combination may affect treatment strategies and outcomes