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Background: Human mesenchymal stem cells (hMSCs) have shown their multipotential including differentiating towards endothelial and smooth muscle cell lineages, which triggers a new interest for using hMSCs as a putative source for cardiovascular regenerative medicine. Our recent publication has shown for the first time that purinergic 2 receptors are key players during hMSC differentiation towards adipocytes and osteoblasts. Purinergic 2 receptors play an important role in cardiovascular function when they bind to extracellular nucleotides. In this study, the possible functional role of purinergic 2 receptors during MSC endothelial and smooth muscle differentiation was investigated. Methods and Results: Human MSCs were isolated from liposuction materials. Then, endothelial and smooth muscle-like cells were differentiated and characterized by specific markers via Reverse Transcriptase-PCR (RT-PCR), Western blot and immunochemical stainings. Interestingly, some purinergic 2 receptor subtypes were found to be differently regulated during these specific lineage commitments: P2Y4 and P2Y14 were involved in the early stage commitment while P2Y1 was the key player in controlling MSC differentiation towards either endothelial or smooth muscle cells. The administration of natural and artificial purinergic 2 receptor agonists and antagonists had a direct influence on these differentiations. Moreover, a feedback loop via exogenous extracellular nucleotides on these particular differentiations was shown by apyrase digest. Conclusions: Purinergic 2 receptors play a crucial role during the differentiation towards endothelial and smooth muscle cell lineages. Some highly selective and potent artificial purinergic 2 ligands can control hMSC differentiation, which might improve the use of adult stem cells in cardiovascular tissue engineering in the future.
Extremophiles are optimal models in experimentally addressing questions about the effects of cosmic radiation on biological systems. The resistance to high charge energy (HZE) particles, and helium (He) ions and iron (Fe) ions (LET at 2.2 and 200 keV/µm, respectively, until 1000 Gy), of spores from two thermophiles, Bacillushorneckiae SBP3 and Bacilluslicheniformis T14, and two psychrotolerants, Bacillus sp. A34 and A43, was investigated. Spores survived He irradiation better, whereas they were more sensitive to Fe irradiation (until 500 Gy), with spores from thermophiles being more resistant to irradiations than psychrotolerants. The survived spores showed different germination kinetics, depending on the type/dose of irradiation and the germinant used. After exposure to He 1000 Gy, D-glucose increased the lag time of thermophilic spores and induced germination of psychrotolerants, whereas L-alanine and L-valine increased the germination efficiency, except alanine for A43. FTIR spectra showed important modifications to the structural components of spores after Fe irradiation at 250 Gy, which could explain the block in spore germination, whereas minor changes were observed after He radiation that could be related to the increased permeability of the inner membranes and alterations of receptor complex structures. Our results give new insights on HZE resistance of extremophiles that are useful in different contexts, including astrobiology.
This work thoroughly investigates a semi-Lagrangian lattice Boltzmann (SLLBM) solver for compressible flows. In contrast to other LBM for compressible flows, the vertices are organized in cells, and interpolation polynomials up to fourth order are used to attain the off-vertex distribution function values. Differing from the recently introduced Particles on Demand (PoD) method , the method operates in a static, non-moving reference frame. Yet the SLLBM in the present formulation grants supersonic flows and exhibits a high degree of Galilean invariance. The SLLBM solver allows for an independent time step size due to the integration along characteristics and for the use of unusual velocity sets, like the D2Q25, which is constructed by the roots of the fifth-order Hermite polynomial. The properties of the present model are shown in diverse example simulations of a two-dimensional Taylor-Green vortex, a Sod shock tube, a two-dimensional Riemann problem and a shock-vortex interaction. It is shown that the cell-based interpolation and the use of Gauss-Lobatto-Chebyshev support points allow for spatially high-order solutions and minimize the mass loss caused by the interpolation. Transformed grids in the shock-vortex interaction show the general applicability to non-uniform grids.
Studi ini bertujuan untuk memvalidasi perangkat penilaian efikasi diri yang berkaitan dengan kesehatan kerja yang dikembangkan pada tahap studi pendahuluan. Skala Efikasi Diri untuk Kesehatan Kerja (SEDKK) berlandaskan konsep efikasi diri pada teori kognitif sosial yang mengukur empat faktor yang berpengaruh pada kesehatan setiap individu yang bekerja, seperti: perilaku makan dan minum, tidur, keamanan dan kesehatan kerja, serta kegiatan pemulihan dari stres bekerja. Hasil analisis faktor eksploratori menunjukan bahwa ada empat faktor yang terefleksikan dari butir-butir SEDKK. Validitas konstruk SEDKK dapat dibuktikan dengan korelasi positif antara SEDKK dan skala Efikasi Diri Umum yang sangat signifikan. Pengujian validitas kriteria dapat ditelusuri melalui efek SEDKK terhadap kondisi kesehatan umum, kepuasan akan kesehatan pribadi, keseimbangan kehidupan kerja/KKK (work life balance), perilaku sehat, dan perilaku berisiko. Namun demikian, asumsi mengenai reliabilitas tes berulang (test-retest) pada penelitian ini ditolak. Implikasi dan saran-saran untuk penelitian selanjutnya didiskusikan pada artikel ini.
The development of sustainable, environmentally friendly insulation materials with a reduced carbon footprint is attracting increased interest. One alternative to conventional insulation materials are foamed geopolymers. Similar to foamed concrete, the mechanical properties of geopolymer foams can also be improved by using fibers for reinforcement. This paper presents an overview of the latest research findings in the field of fiber-reinforced geopolymer foam concrete with special focus on natural fibers reinforcement. Furthermore, some basic and background information of natural fibers and geopolymer foams are reported. In most of the research, foams are produced either through chemical foaming with hydrogen peroxide or aluminum powder, or through mechanical foaming which includes a foaming agent. However, previous reviews have not sufficiently addresses the fabrication of geopolymer foams by syntactic foams. Finally, recent efforts to reduce the fiber degradation in geopolymer concrete are discussed along with challenges for natural fiber reinforced-geopolymer foam concrete.
Who do you trust: Peers or Technology? A conjoint analysis about computational reputation mechanisms
(2020)
Peer-to-peer sharing platforms are taking over an increasingly important role in the platform economy due to their sustainable business model. By sharing private goods and services, the challenge arises to build trust between peers online mostly without any kind of physical presence. Peer rating has been proven as an important mechanism. In this paper, we explore the concept called Trust Score, a computational rating mechanism adopted from car telematics, which can play a similar role in carsharing. For this purpose, we conducted a conjoint analysis where 77 car owners chose between fictitious user profiles. Our results show that in our experiment the telemetric-based score slightly outperforms the peer rating in the decision process, while the participants perceived the peer rating more helpful in retrospect. Further, we discuss potential benefits with regard to existing shortcomings of user rating, but also various concerns that should be considered in concepts like telemetric-based reputation mechanism that supplements existing trust factors such as user ratings.
Background: While work-related rumination increases the risk of acute stressors developing into chronic load reactions and adverse health, mental detachment has been suggested as a way to interrupt this chain. Despite the importance of mentally detaching from work during leisure time, workers seem to struggle to disengage and, instead, experience the constant mental representation of work-related stressors, regardless of their absence. Those who struggle with work-related rumination could benefit from an easy-access intervention that fosters mental detachment by promoting recreational activities. Especially during vacations, workers appear to naturally engage in sufficient recovery activities; however, this beneficial behaviour is not sustained. The smartphone app-based intervention “Holidaily” promotes recovery behaviour and, thus, mental detachment from work with the intension of extending the beneficial effects of workers’ vacations into their daily working life.
Methods: This randomised-controlled trial (RCT) evaluates the efficacy of “Holidaily”. The Holidaily app is a German stand-alone program for mobile devices with either Android/iOS operating systems. The sample includes workers, who are awaiting to go on vacation and are randomly assigned to either the intervention (IG) or a waitlist-control group (CG). The IG receives two weeks pre-vacation access to Holidaily, while the CG receives access two weeks post-vacation. On a daily basis participants in the IG are provided with three options promoting recreational activities and beneficial recovery experiences. Online questionnaires are distributed to all participants at several timepoints. The primary outcome measure assesses participants’ work-related rumination (Irritation Scale). A significant difference two weeks post-vacation is expected, favouring the IG. Secondary outcomes include symptoms of depression, insomnia severity, emotional exhaustion, thinking about work, recovery experiences, vacation specifics, work and personal characteristics. To help explain the intervention’s effect, explorative analyses will investigate the mediation properties of the frequency of engaging in recreational activities and the moderation properties of Holidaily users’ experiences.
Discussion: If successful, workers will maintain their recovery behaviour beyond their vacation into daily working life. Findings could, therefore, provide evidence for low-intensity interventions that could be very valuable from a public-health perspective. App-based interventions have greater reach; hence, more workers might access preventative tools to protect themselves from developing adverse health effects linked to work-related rumination. Further studies will still be needed to investigate whether the vacation phenomenon of “lots of fun quickly gone” can be defied and long-term benefits attained.
Medien spielen eine Schlüsselrolle für die öffentliche Meinung und Akzeptanz neuer Technologien. Mit einer qualitativen Inhaltsanalyse journalistischer Artikel zum Elektrofahrrad wurden Akteure und ihre Einstellungen und Handlungen in Bezug auf das Elektrofahrrad untersucht. In die Analyse flossen 444 Artikel ausgewählter deutscher Qualitätsmedien aus dem Jahr 2018 ein. Die Untersuchung zeigt den gesellschaftlich relevanten Diskurs über Elektrofahrräder auf und bietet Anknüpfungspunkte für die Förderung von Individualmobilität und der Entwicklung zukunftsfähiger Mobilitätskonzepte.