| 1. |
- Campbell, Kate, 1987, et al.
(författare)
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Cell-to-cell heterogeneity emerges as consequence of metabolic cooperation in a synthetic yeast community
- 2016
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Ingår i: Biotechnology journal. - : Wiley. - 1860-6768 .- 1860-7314. ; 11:9, s. 1169-1178
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Tidskriftsartikel (refereegranskat)abstract
- Cells that grow together respond heterogeneously to stress even when they are genetically similar. Metabolism, a key determinant of cellular stress tolerance, may be one source of this phenotypic heterogeneity, however, this relationship is largely unclear. We used self-establishing metabolically cooperating (SeMeCo) yeast communities, in which metabolic cooperation can be followed on the basis of genotype, as a model to dissect the role of metabolic cooperation in single-cell heterogeneity. Cells within SeMeCo communities showed to be highly heterogeneous in their stress tolerance, while the survival of each cell under heat or oxidative stress, was strongly determined by its metabolic specialization. This heterogeneity emerged for all metabolite exchange interactions studied (histidine, leucine, uracil, and methionine) as well as oxidant (H2O2, diamide) and heat stress treatments. In contrast, the SeMeCo community collectively showed to be similarly tolerant to stress as wild-type populations. Moreover, stress heterogeneity did not establish as sole consequence of metabolic genotype (auxotrophic background) of the single cell, but was observed only for cells that cooperated according to their metabolic capacity. We therefore conclude that phenotypic heterogeneity and cell to cell differences in stress tolerance are emergent properties when cells cooperate in metabolism.
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| 2. |
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Den empiriska glädjen. En vänbok till Malin Åkerström
- 2023
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Samlingsverk (redaktörskap) (övrigt vetenskapligt/konstnärligt)abstract
- Det finns energi att hämta i empiriska iakttagelser och det kan vara enfröjd att utvinna den energin. Så lyder budskapet i den här vänbokentill Malin Åkerström, professor emerita vid Lunds universitet.Med nedslag i vitt skilda fält och projekt vill författarna exemplifieraoch analysera det speciella samspel som äger rum mellan empirioch forskare i olika samhällsvetenskapliga ämnen. Det rör sig om entolkande aktivitet som är nyfiken och öppen för överraskningar ochlyckoträffar.Malin Åkerström har under flera decennier bedrivit forskning i denhär andan och publicerat en rad färgstarka och stilbildande böckeroch artiklar.Den empiriska glädjen är en antologi uppdelad i fyra delar: brott ochstraff, kultur och kontroll, interaktioner och ritualer samt forskare ochfält. Boken innehåller bidrag från 30 författare vid olika lärosäten ochriktar sig till forskare och studenter i sociologi, kriminologi, socialtarbete och socialantropologi samt angränsande ämnen.
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| 3. |
- Yeddu, Hemantha Kumar, et al.
(författare)
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Multi-length scale modeling of martensitic transformations in stainless steels
- 2012
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Ingår i: Acta Materialia. - : Elsevier BV. - 1359-6454 .- 1873-2453. ; 60:19, s. 6508-6517
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Tidskriftsartikel (refereegranskat)abstract
- In the present work a multi-length scale model is developed to study both the athermal and stress-assisted martensitic transformations in a single crystal of 301 type stainless steel. The microstructure evolution is simulated using elastoplastic phase-field simulations in three dimensions. The input data for the simulations is acquired from a combination of computational techniques and experimental works. The driving force for the transformation is calculated by using the CALPHAD technique and the elastic constants of the body-centered cubic phase are calculated by using ab initio method. The other input data is acquired from experimental works. The simulated microstructures resemble a lath-type martensitic microstructure, which is in good agreement with the experimental results obtained for a stainless steel of similar composition. The martensite habit plane predicted by the model is in accordance with experimental results. The Magee effect, i.e. formation of favorable martensite variants depending on the loading conditions, is observed in the simulations. The results also indicate that anisotropic loading conditions give rise to a significant anisotropy in the martensitic microstructure.
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| 6. |
- Hobzova, Radka, et al.
(författare)
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Embedding of Bacterial Cellulose Nanofibers within PHEMA Hydrogel Matrices: Tunable Stiffness Composites with Potential for Biomedical Applications
- 2018
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Ingår i: Journal of Nanomaterials. - : Hindawi Limited. - 1687-4129 .- 1687-4110. ; 2018
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Tidskriftsartikel (refereegranskat)abstract
- Bacterial cellulose (BC) and poly(2-hydroxyethyl methacrylate) (PHEMA) hydrogels are both considered as biocompatible materials with potential use in various biomedical applications including cartilage, cardiovascular stent, and soft tissue engineering. In this work, the "ever-wet" process based on in situ UV radical polymerization of HEMA monomer in BC nanofibrous structure impregnated with HEMA was used, and a series of BC-PHEMA composites was prepared. The composite structures were characterized by ATR FT-IR spectroscopy, WAXD, SEM, and TEM techniques. The strategy of using densified BC material of various cellulose fiber contents was applied to improve mechanical properties. The mechanical properties were tested under tensile, dynamic shear, and relaxation modes. The final composites contained 1 to 20 wt% of BC; the effect of the reinforcement degree on morphology, swelling capacity, and mechanical properties was investigated. The biocompatibility test of BC-PHEMA composites was performed using mouse mesenchymal stem cells.
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| 7. |
- Mishchenko, Petr A., et al.
(författare)
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Chiral spin liquids with crystalline Z(2) gauge order in a three-dimensional Kitaev model
- 2020
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Ingår i: Physical Review B. - : AMER PHYSICAL SOC. - 2469-9950 .- 2469-9969. ; 101:4
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Tidskriftsartikel (refereegranskat)abstract
- Chiral spin liquids (CSLs) are time-reversal-symmetry-breaking ground states of frustrated quantum magnets that show no long-range magnetic ordering but instead exhibit topological order and fractional excitations. Their realization in simple and tractable microscopic models has, however, remained an open challenge for almost two decades until it was realized that Kitaev models on lattices with odd-length loops are natural hosts for such states, even in the absence of a time-reversal-symmetry-breaking magnetic field. Here we report on the formation of CSLs in a three-dimensional Kitaev model on a hypernonagon lattice composed of nine-site loops, which differ from their widely studied two-dimensional counterparts; namely, they exhibit a crystalline ordering of the Z(2) gauge fluxes and thereby break some of the underlying lattice symmetries. We study the formation of these unconventional CSLs via extensive quantum Monte Carlo simulations and demonstrate that they are separated from the featureless paramagnet at high temperatures by a single first-order phase transition at which both time-reversal and lattice symmetries are simultaneously broken. Using variational approaches for the ground state, we explore the effect of varying the Kitaev couplings and find at least five distinct CSL phases, all of which possess crystalline ordering of the Z(2) gauge fluxes. For some of these phases, the complementary itinerant Majorana fermions exhibit gapless band structures with topological features such as Weyl nodes or nodal lines in the bulk and Fermi arc or drumhead surface states.
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| 8. |
- Rodríguez, Juanjo
(författare)
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Mercury methylation in boreal aquatic ecosystems under oxic conditions and climate change : a review
- 2023
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Ingår i: Frontiers in Marine Science. - : Frontiers Media S.A.. - 2296-7745. ; 10
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Forskningsöversikt (refereegranskat)abstract
- Methylmercury (MeHg) formation is a concerning environmental issue described in waters and sediments from multiple aquatic ecosystems. The genetic and metabolic bases of mercury (Hg) methylation have been well described in anoxic environments, but a number of factors seem to point towards alternative pathways potentially occurring in pelagic waters under oxic conditions. Boreal aquatic ecosystems are predicted to undergo increasing concentrations of dissolved organic matter (DOM) as a result of higher terrestrial runoff induced by climate change, which may have important implications in the formation of MeHg in the water column. In this review, different Hg methylation mechanisms postulated in the literature are discussed, with particular focus on potential pathways independent of the hgcAB gene pair and occurring under oxic conditions. Potential effects of DOM on Hg methylation and MeHg bioaccumulation are examined in the context of climate in boreal aquatic ecosystems. Furthermore, the implementation of meta-omic technologies and standardized methods into field measurements and incubation experiments is discussed as a valuable tool to determine taxonomic and functional aspects of Hg methylation in oxic waters and under climate change-induced conditions.
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| 10. |
- Winkel, Jörgen, 1946, et al.
(författare)
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Facilitating and inhibiting factors in change processes based on the lean tool ‘value stream mapping’: an exploratory case study at hospital wards
- 2015
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Ingår i: International Journal of Human Factors and Ergonomics. - 2045-7804 .- 2045-7812. ; 3:3/4, s. 291-302
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Tidskriftsartikel (refereegranskat)abstract
- “Lean production” has become a prevalent rationalization methodology in healthcare. Value Stream Mapping (VSM) is a commonly used Lean tool to identify non-Value-Adding-Work. VSM is a participatory tool. Thus it may offer an opportunity to combine interventions for improved performance and ergonomics. The aim of the present exploratory study is to report observations that seem to play significant roles as inhibitors and facilitators for proper intervention processes when using VSM. Seven hospital wards have been investigated in Denmark, Iceland and Sweden. Information was obtained by screening key hospital documents and interviewing participants in and around the VSM processes. Nine tape-recorded interviews were performed. The results tentatively point to the facilitating effect on the VSM process by emphasizing involvement and decision-making among the participants, 1st line manager support and engagement, allocation of sufficient resources, work environment issues as part of the VSM methodology and VSM routines that are well-established and broadly accepted.
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