Drawing upon the self-determination theory, we develop a two-stage multi-path mediation model in which psychological autonomy mediates the relationship between active engagement in entrepreneurship ...and well-being partially through its effect on psychological competence and relatedness. We test this model on a representative sample of 1837 working individuals (251 early-stage entrepreneurs) from Sweden. We find active engagement in entrepreneurial work tasks to be strongly associated with well-being relative to non-entrepreneurial work. Thus, we highlight the importance of individual self-organization—with autonomy at its core—which makes entrepreneurial work more beneficial in terms of basic psychological needs compared to other work alternatives.
•We examine variations in well-being and basic psychological needs between entrepreneurs and non-entrepreneurial employees.•We draw on a unique and representative data sample, originates from the 2011 Swedish Global Entrepreneurship Monitor.•Our analysis clearly shows that well-being is strongly and positively associated with entrepreneurial task engagements.•Our theorizing demonstrates the positive contribution of entrepreneurship to basic psychological needs and well-being.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Load‐bearing soft tissues, e.g., cartilage, ligaments, and blood vessels, are made predominantly from water (65–90%) which is essential for nutrient transport to cells. Yet, they display amazing ...stiffness, toughness, strength, and deformability attributed to the reconfigurable 3D network from stiff collagen nanofibers and flexible proteoglycans. Existing hydrogels and composites partially achieve some of the mechanical properties of natural soft tissues, but at the expense of water content. Concurrently, water‐rich biomedical polymers are elastic but weak. Here, biomimetic composites from aramid nanofibers interlaced with poly(vinyl alcohol), with water contents of as high as 70–92%, are reported. With tensile moduli of ≈9.1 MPa, ultimate tensile strains of ≈325%, compressive strengths of ≈26 MPa, and fracture toughness of as high as ≈9200 J m−2, their mechanical properties match or exceed those of prototype tissues, e.g., cartilage. Furthermore, with reconfigurable, noncovalent interactions at nanomaterial interfaces, the composite nanofiber network can adapt itself under stress, enabling abiotic soft tissue with multiscale self‐organization for effective load bearing and energy dissipation.
Water‐rich biomimetic composites from aramid nanofibers interlaced with poly(vinyl alcohol) emulate the collagen–proteoglycan network in load‐bearing soft tissues. The hydrogen bonding between stiff nanofibers and soft polymers affords synergistic stiffening and toughening, allowing the nanofiber network to self‐organize under stress for effective load bearing and energy dissipation. Their mechanics, biocompatibility, and high water content permit utilization as load‐bearing biomaterials and for other applications including durable high‐transport‐rate membranes, membranes in water desalination, fuel cells, and batteries.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
sociobiology of biofilms Nadell, Carey D; Xavier, Joao B; Foster, Kevin R
FEMS microbiology reviews,
2009, January 2009, 2009-Jan, 2009-01-00, 20090101, Volume:
33, Issue:
1
Journal Article
Peer reviewed
Open access
Biofilms are densely packed communities of microbial cells that grow on surfaces and surround themselves with secreted polymers. Many bacterial species form biofilms, and their study has revealed ...them to be complex and diverse. The structural and physiological complexity of biofilms has led to the idea that they are coordinated and cooperative groups, analogous to multicellular organisms. We evaluate this idea by addressing the findings of microbiologists from the perspective of sociobiology, including theories of collective behavior (self-organization) and social evolution. This yields two main conclusions. First, the appearance of organization in biofilms can emerge without active coordination. That is, biofilm properties such as phenotypic differentiation, species stratification and channel formation do not necessarily require that cells communicate with one another using specialized signaling molecules. Second, while local cooperation among bacteria may often occur, the evolution of cooperation among all cells is unlikely for most biofilms. Strong conflict can arise among multiple species and strains in a biofilm, and spontaneous mutation can generate conflict even within biofilms initiated by genetically identical cells. Biofilms will typically result from a balance between competition and cooperation, and we argue that understanding this balance is central to building a complete and predictive model of biofilm formation.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Alternating‐voltage anodization of titanium foil in a fluoride‐containing electrolyte allowed novel, self‐organized nanoscale morphologies of TiO2 to be grown, such as reinforced nanotubes ...(nanobamboo) and laterally extended two‐dimensional networks (nanolace).
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Polyoxometalates (POMs) are a subset of metal oxides that represent a diverse range of molecular clusters with an almost unmatched range of physical properties and the ability to form dynamic ...structures that can range in size from the nano- to the micrometer scale. Herein we present the very latest developments from synthesis to structure and function of POMs. We discuss the possibilities of creating highly sophisticated functional hierarchical systems with multiple, interdependent, functionalities along with a critical analysis that allows the non-specialist to learn the salient features. We propose and present a "periodic table of polyoxometalate building blocks". We also highlight some of the current issues and challenges that need to be addressed to work towards the design of functional systems based upon POM building blocks and look ahead to possible emerging application areas.
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Laser surface structuring has been demonstrated to be a versatile technology to create various functional materials by modifying solid surface properties. An interesting experimental phenomenon of ...self‐organized periodic microholes array formation is demonstrated by exposing an aluminum surface to femtosecond laser irradiation. The microholes with a diameter much smaller than focal laser spot size are produced along laser scan paths due to the incubation effect of multiple laser scans, and they spontaneously form a highly ordered microholes array after 80 scans. It is found that the microhole period and diameter are highly dependent on laser fluence, and controllable microholes arrays with different periods and diameters are achieved by adjusting laser fluence. The physical mechanism behind the formation of the microholes array is attributed to femtosecond laser‐induced melting and Marangoni effect. The research provides a novel processing approach to achieve controllable microholes surface materials fabrication at a high speed on metal substrates, which are of great interests for various technological applications.
Self‐organized periodic microholes array formation on aluminum surface is observed via multiple femtosecond laser scans. The microholes period and diameter are found to be highly dependent on laser fluence, and controllable microholes arrays with a period from 10.5 to 33.5 µm and diameter from 5.6 to 17.4 µm are demonstrated by adjusting laser fluence.
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Efficient and stable catalysts for ammonia synthesis under mild conditions are required to meet the strong demand for NH3 as an important precursor chemical and hydrogen carrier. Here we report that ...during ammonia synthesis, flat-shaped Ru nanoparticles with a narrow distribution (2.1 ± 1.0 nm) and self-organized on Ca(NH2)2 exhibit high catalytic performance far exceeding alkali-promoted Ru-based catalysts in yield and turnover frequency (TOF). This catalyst enables continuous NH3 production, even at 473 K under ambient pressure. During ammonia synthesis, Ru nanoparticles are distinctly anchored on the surface of Ca(NH2)2 by strong Ru–N interaction, which leads to the epitaxial growth of Ru on the support surface. The high catalytic performance is due to the formation of high-density flat-shaped Ru nanoparticles and high electron donor ability at the Ru/Ca(NH2)2 interface. The catalytic stability is significantly improved by Ba-doping of Ca(NH2)2, and no degradation was observed after ca. 700 h of operation.
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IJS, KILJ, NUK, PNG, UL, UM
Savannas are highly variable systems, and predicting variation, especially in the tree layer, represents a major unresolved challenge for forecasting biosphere responses to global change. Prediction ...to date has focused on disentangling interactions between resource limitation and chronic disturbances to identify what determines local savanna vegetation heterogeneity. By focusing at too fine a scale, this approach overlooks: sample size limitation arising fromsparse tree distributions; stochasticity in demographic and environmental processes that is preserved as heterogeneity among tree populations with slow dynamics; and spatial self-organization. Renewedfocus on large (1–50 ha) permanent plots and on spatial patterns of tree-layer variability at even larger landscape spatial scales (≥1000s of ha) promises to resolve these limitations, consistent with the goal of predicting large-scale biosphere responses to global change.
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The self‐organization of the polymer in solar cells based on regioregular poly(3‐hexylthiophene) (RR‐P3HT):6,6‐phenyl C61‐butyric acid methyl ester (PCBM) is studied systematically as a function of ...the spin‐coating time ts (varied from 20–80 s), which controls the solvent annealing time ta, the time taken by the solvent to dry after the spin‐coating process. These blend films are characterized by photoluminescence spectroscopy, UV‐vis absorption spectroscopy, atomic force microscopy, and grazing incidence X‐ray diffraction (GIXRD) measurements. The results indicate that the π‐conjugated structure of RR‐P3HT in the films is optimally developed when ta is greater than 1 min (ts ∼ 50 s). For ts < 50 s, both the short‐circuit current (JSC) and the power conversion efficiency (PCE) of the corresponding polymer solar cells show a plateau region, whereas for 50 < ts < 55 s, the JSC and PCE values are significantly decreased, suggesting that there is a major change in the ordering of the polymer in this time window. The PCE decreases from 3.6 % for a film with a highly ordered π‐conjugated structure of RR‐P3HT to 1.2 % for a less‐ordered film. GIXRD results confirm the change in the ordering of the polymer. In particular, the incident photon‐to‐electron conversion efficiency spectrum of the less‐ordered solar cell shows a clear loss in both the overall magnitude and the long‐wavelength response. The solvent annealing effect is also studied for devices with different concentrations of PCBM (PCBM concentrations ranging from 25 to 67 wt %). Under “solvent annealing” conditions, the polymer is seen to be ordered even at 67 wt % PCBM loading. The open‐circuit voltage (VOC) is also affected by the ordering of the polymer and the PCBM loading in the active layer.
Polymer solar cells based on poly(3‐hexylthiophene) and methanofullerenes are investigated by systematically varying the spin‐coating time used during fabrication (see figure). The rate of solvent evaporation profoundly effects the self‐organization of the polymer. Very high crystallinity of the polymer and consequently optimal solar‐cell performance is achieved for longer “solvent annealing” times.
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