Browsing by Subject "TRANSITIONS"

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  • Kylkilahti, Eliisa; Berghäll, Sami; Autio, Minna; Nurminen, Jonne; Toivonen, Ritva; Lähtinen, Katja; Vihemäki, Heini; Franzini, Florencia; Toppinen, Anne (2020)
    Consumer acceptance of new bio-based products plays a key role in the envisioned transition towards a forest-based bioeconomy. Multi-storey wooden buildings (MSWB) exemplify a modern, bio-based business opportunity for enacting low-carbon urban housing. However, there is limited knowledge about the differing perceptions consumers hold regarding wood as an urban building material. To fill this gap, this study explores Finnish students' perceptions of MSWB relative to their familiarity with wooden residential buildings, and then connects these perceptions to 'consumption styles.' Data were collected in the Helsinki metropolitan area via an online questionnaire (n = 531). The results indicate that the aesthetic appearance of MSWB are appreciated most by frugal and responsible consumers, whereas the comfort, environmental friendliness, and longevity of MSWB are important to consumers who identify themselves as 'thoughtful spenders.' The study suggests that both environmental and hedonic young consumers already familiar with the use of wood in housing contribute to a successful bioeconomy in the urban context.
  • Sacchi, Giovanna; Cei, Leonardo; Stefani, Gianluca; Lombardi, Ginevra Virginia; Rocchi, Benedetto; Belletti, Giovanni; Padel, Susanne; Sellars, Anna; Gagliardi, Edneia; Nocella, Giuseppe; Cardey, Sarah; Mikkola, Minna Maria; Ala-Karvia, Urszula Anna; Macken-Walsh, Àine; McIntyre, Bridin; Hyland, John; Henchion, Maeve; Bocci, Riccardo; Bussi, Bettina; De Santis, Giuseppe; Rodriguez y Hurtado, Ismael; de Kochko, Patrick; Riviere, Pierre; Carrascosa-García, María; Martínez, Ignacio; Pearce, Bruce; Lampkin, Nic; Vindras, Camille; Rey, Frederic; Chable, Véronique; Cormery, Antoine; Vasvari, Gyula (2018)
    Organic and low-input food systems are emerging worldwide in answer to the sustainability crisis of the conventional agri-food sector. “Alternative” systems are based on local, decentralized approaches to production and processing, regarding quality and health, and short supply-chains for products with strong local identities. Diversity is deeply embedded in these food systems, from the agrobiodiversity grown in farmers’ fields, which improves resilience and adaptation, to diverse approaches, contexts and actors in food manufacturing and marketing. Diversity thus becomes a cross-sectoral issue which acknowledges consumers’ demand for healthy products. In the framework of the European project “CERERE, CEreal REnaissance in Rural Europe: embedding diversity in organic and low-input food systems”, the paper aims at reviewing recent research on alternative and sustainable food systems by adopting an innovative and participatory multi-actor approach; this has involved ten practitioners and twenty-two researchers from across Europe and a variety of technical backgrounds in the paper and analysis stages. The participatory approach is the main innovation and distinctive feature of this literature review. Partners selected indeed what they perceived as most relevant in order to facilitate a transition towards more sustainable and diversity based cereal systems and food chains. This includes issues related to alternative food networks, formal and informal institutional settings, grass root initiatives, consumer involvement and, finally, knowledge exchange and sustainability. The review provides an overview of recent research that is relevant to CERERE partners as well as to anyone interested in alternative and sustainable food systems. The main objective of this paper was indeed to present a narrative of studies, which can form the foundation for future applied research to promote alternative methods of cereal production in Europe.
  • Vroomans, Renske M. A.; Hogeweg, Paulien; ten Tusscher, Kirsten H. W. J. (2018)
    BackgroundSegmentation, the subdivision of the major body axis into repeated elements, is considered one of the major evolutionary innovations in bilaterian animals. In all three segmented animal clades, the predominant segmentation mechanism is sequential segmentation, where segments are generated one by one in anterior-posterior order from a posterior undifferentiated zone. In vertebrates and arthropods, sequential segmentation is thought to arise from a clock-and-wavefront-type mechanism, where oscillations in the posterior growth zone are transformed into a segmental prepattern in the anterior by a receding wavefront. Previous evo-devo simulation studies have demonstrated that this segmentation type repeatedly arises, supporting the idea of parallel evolutionary origins in these animal clades. Sequential segmentation has been studied most extensively in vertebrates, where travelling waves have been observed that reflect the slowing down of oscillations prior to their cessation and where these oscillations involve a highly complex regulatory network. It is currently unclear under which conditions this oscillator complexity and slowing should be expected to evolve, how they are related and to what extent similar properties should be expected for sequential segmentation in other animal species.ResultsTo investigate these questions, we extend a previously developed computational model for the evolution of segmentation. We vary the slope of the posterior morphogen gradient and the strength of gene expression noise. We find that compared to a shallow gradient, a steep morphogen gradient allows for faster evolution and evolved oscillator networks are simpler. Furthermore, under steep gradients, damped oscillators often evolve, whereas shallow gradients appear to require persistent oscillators which are regularly accompanied by travelling waves, indicative of a frequency gradient. We show that gene expression noise increases the likelihood of evolving persistent oscillators under steep gradients and of evolving frequency gradients under shallow gradients. Surprisingly, we find that the evolutions of oscillator complexity and travelling waves are not correlated, suggesting that these properties may have evolved separately.ConclusionsBased on our findings, we suggest that travelling waves may have evolved in response to shallow morphogen gradients and gene expression noise. These two factors may thus also be responsible for the observed differences between different species within both the arthropod and chordate phyla.
  • Grundström, Jenna; Konttinen, Hanna; Berg, Noora; Kiviruusu, Olli (2021)
    The aim of this study was to assess the associations between relationship status and mental well-being in four different phases during the life course, and to identify whether relationship quality moderated these associations. We used a broader concept of relationship status (instead of marital status) and also included the positive dimension of mental health. Participants in a Finnish cohort study were followed up at ages 22 (N = 1,656), 32 (N = 1,471), 42 (N = 1,334), and 52 (N = 1,159). Measures in all study panels covered relationship status (marriage, cohabitation, dating, single and divorced/widowed), Short Beck Depression Inventory (S-BDI), self-esteem (seven items) and relationship quality (six items). Analyses were carried out using linear regression. Compared to marriage, being single or being divorced/widowed were associated with depressive symptoms at every age in men. For women, in turn, being single - but not being divorced/widowed - was associated with depressive symptoms. Among men, being single or being divorced/widowed were also associated with lower self-esteem at age 32, 42 and 52, but in women, only one association between lower self-esteem and being single was found at age 32. Of the age stages, the age 32 is highlighted in men, at which point all relationship statuses were risk factors compared to marriage. There were only few indications of the moderating role of the relationship quality. Compared to marriage, being single or being divorced/widowed were quite consistently associated with poorer mental well-being during the life course, especially among men. For dating and cohabiting the associations were more fragmented depending on age and gender; particularly among women, these relationship statuses tended not to differ from marriage in terms of mental well-being. These observations on mental well-being across five relationship statuses are important in our contemporary society, where the number of marriages is decreasing, and other forms of relationships are becoming more common.
  • Stepien, Piotr; Augustyn, Bozena; Poojari, Chetan; Galan, Wojciech; Polit, Agnieszka; Vattulainen, Ilpo; Wisnieska-Becker, Anna; Rog, Tomasz (2020)
    Lipid nanodiscs are macromolecular assemblies, where a scaffold protein is wrapped around a nanosized disc of a lipid bilayer, thus protecting the hydrocarbon chains at the disc edges from unfavorable interactions with water. These nanostructures have numerous applications in, e.g., nanotechnology and pharmaceutics, and in investigations of membrane proteins. Here, we present results based on atomistic molecular dynamics simulations combined with electron paramagnetic spectroscopy measurements on the structure and dynamics of lipids in single-component nanodiscs. Our data highlight the existence of three distinctly different lipid fractions: central lipids residing in the center of a nanodisc, boundary lipids in direct contact with a scaffold protein, and intermediate lipids between these two regions. The central lipids are highly ordered and characterized by slow diffusion. In this part of the nanodisc, the membrane is the thickest and characterized by a gel-like or liquid-ordered phase, having features common to cholesterol-rich membranes. The boundary lipids in direct contact with the scaffold protein turned out to be less ordered and characterized by faster diffusion, and they remained in the liquid-disordered phase even at temperatures that were somewhat below the main phase transition temperature (Tm). The enthalpies associated with the central-boundary and central-intermediate transitions were similar to those observed for lipids going through the main phase transition. Overall, the study reveals lipid nanodiscs to be characterized by a complex internal structure, which is expected to influence membrane proteins placed in nanodiscs.
  • Deckwirth, Vivi; Rajakylä, Eeva Kaisa; Cattavarayane, Sandhanakrishnan; Acheva, Anna; Schaible, Niccole; Krishnan, Ramaswamy; Valle-Delgado, Juan Jose; Osterberg, Monika; Björkenheim, Pia; Sukura, Antti; Tojkander, Sari (2021)
    At invasion, transformed mammary epithelial cells expand into the stroma through a disrupted myoepithelial (ME) cell layer and basement membrane (BM). The intact ME cell layer has thus been suggested to act as a barrier against invasion. Here, we investigate the mechanisms behind the disruption of ME cell layer. We show that the expression of basal/ME proteins CK5, CK14, and alpha-SMA altered along increasing grade of malignancy, and their loss affected the maintenance of organotypic 3D mammary architecture. Furthermore, our data suggests that loss of CK5 prior to invasive stage causes decreased levels of Zinc finger protein SNAI2 (SLUG), a key regulator of the mammary epithelial cell lineage determination. Consequently, a differentiation bias toward luminal epithelial cell type was detected with loss of mature, alpha-SMA-expressing ME cells and reduced deposition of basement membrane protein laminin-5. Therefore, our data discloses the central role of CK5 in mammary epithelial differentiation and maintenance of normal ME layer.
  • Posti-Ahokas, Hanna (2013)
    Tanzania, like many other African countries, has experienced a rapid expansion of its secondary education sector. This has resulted in large numbers of secondary school graduates struggling to build a future through continuing education or finding employment. 1 Students are faced with the difficult task of assessing their opportunities in the face of various challenges and making plans to build a better life. The presented research uses empathy-based stories to identify which elements were considered to be important by students in determining their success in education. The analysis of narrative data represents a shared cultural meaning on the social and cultural support available to students. The findings suggest that using empathy-based stories as a methodological tool can provide valuable insights for culture-sensitive and intercultural research through its ability to widen the context of discovery.
  • Dudel, Christian; Myrskylä, Mikko (2020)
    Background Markov models are a key tool for calculating expected time spent in a state, such as active life expectancy and disabled life expectancy. In reality, individuals often enter and exit states recurrently, but standard analytical approaches are not able to describe this dynamic. We develop an analytical matrix approach to calculating the expected number and length of episodes spent in a state. Methods The approach we propose is based on Markov chains with rewards. It allows us to identify the number of entries into a state and to calculate the average length of episodes as total time in a state divided by the number of entries. For sampling variance estimation, we employ the block bootstrap. Two case studies that are based on published literature illustrate how our methods can provide new insights into disability dynamics. Results The first application uses a classic textbook example on prednisone treatment and liver functioning among liver cirrhosis patients. We replicate well-known results of no association between treatment and survival or recovery. Our analysis of the episodes of normal liver functioning delivers the new insight that the treatment reduced the likelihood of relapse and extended episodes of normal liver functioning. The second application assesses frailty and disability among elderly people. We replicate the prior finding that frail individuals have longer life expectancy in disability. As a novel finding, we document that frail individuals experience three times as many episodes of disability that were on average twice as long as the episodes of nonfrail individuals. Conclusions We provide a simple analytical approach for calculating the number and length of episodes in Markov chain models. The results allow a description of the transition dynamics that goes beyond the results that can be obtained using standard tools for Markov chains. Empirical applications using published data illustrate how the new method is helpful in unraveling the dynamics of the modeled process.
  • Peltola, Jari; Vainio, Markku; Fordell, Thomas; Hieta, Tuomas; Merimaa, Mikko; Halonen, Lauri (2014)
    We report on a tunable continuous-wave mid-infrared optical parametric oscillator (OPO), which is locked to a fully stabilized near-infrared optical frequency comb using a frequency doubling scheme. The OPO is used for 40 GHz mode-hop-free, frequency-comb-locked scans in the wavelength region between 2.7 and 3.4 x03BC;m. We demonstrate the applicability of the method to high-precision cavity-ring-down spectroscopy of nitrous oxide (N2O) and water (H2O) at 2.85 x00B5;m and of methane (CH4) at 3.2 x03BC;m.
  • Vihemäki, Heini; Toppinen, Anne; Toivonen, Ritva (2020)
    Intermediaries can potentially help reduce institutional lock-ins that slow down sustainability transitions by influencing policy processes, because of their connectedness and often high level of legitimacy. In this paper, we analysed intermediaries seeking to accelerate the diffusion of wooden multi-storey construction (WMC) in Finland, their roles and engagement in policy processes. Increasing the use of wood in construction has high policy support nationally, backed up with climate and forest policies. Yet, market diffusion has been slow. The data consist of qualitative interviews of intermediaries and other actors, participatory observation and a review of secondary materials. The results reveal a complex set of intermediaries, including systemic, niche and regime-based ones. The intermediaries are characterised by multiple goals, partly overlapping roles and means of policy influencing. The low degree of coordination among the intermediaries and the differences in their agenda for transition are critical challenges which limit the effectiveness of their actions.
  • Ertoprak, A.; Qi, C.; Cederwall, B.; Doncel, M.; Jakobsson, U.; Nyako, B. M.; Jaworski, G.; Davies, P.; de France, G.; Kuti, I.; Napoli, D. R.; Wadsworth, R.; Ghugre, S. S.; Raut, R.; Akkus, B.; Al Azri, H.; Algora, A.; de Angelis, G.; Atac, A.; Back, T.; Boso, A.; Clement, E.; Debenham, D. M.; Dombradi, Zs.; Erturk, S.; Gadea, A.; Ghazi Moradi, F.; Gottardo, A.; Huyuk, T.; Ideguchi, E.; Li, H.; Michelagnoli, C.; Modamio, V.; Nyberg, J.; Palacz, M.; Petrache, C. M.; Recchia, F.; Sandzelius, M.; Siciliano, M.; Sohler, D.; Timar, J.; Valiente-Dobon, J. J.; Xiao, Z. G. (2020)
    Lifetimes of negative-parity states have been determined in the neutron deficient semi-magic (N = 50) nucleus Rh-95. The fusion-evaporation reaction Ni-58(Ca-40, 3p) was used to populate high-spin states in Rh-95 at the Grand Accelerateur National d'Ions Lourds (GANIL) accelerator facility. The results were obtained using the Doppler Shift Attenuation Method (DSAM) based on the Doppler broadened line shapes produced during the slowing down process of the residual nuclei in a thick 6 mg/cm(2) metallic target. B(M1) and B(E2) reduced transition strengths are compared with predictions from large-scale shell-model calculations. state-of-the-art theory. Remarkably, the structural features up to moderate angular momentum of nuclei immediately below the N = Z = 50 shell closures can be described with high accuracy in a very simple way by shell-model calculations including only the g(9/2) and p(1/2) subshells. Of special interest is the neutron-proton pair coupling scheme which is expected to appear in the heaviest N=Z nuclei [1,2] and the seniority structure of the N = 50 isotones [3-7]. However, multiple core-excited states have been observed in the semi-magic nuclei of the Sn-100 region [8-10]. The theoretical study of those states is a challenging task, which requires a significantly larger model space for their interpretation. Transition probabilities between nuclear states provide important constraints for theoretical modelling of the structure of the nuclei of interest. Our previous lifetime study of the semimagic (N = 50) nucleus Ru-94 [ 11,12] provided information on the electromagnetic decay properties of neutron-core excited states. We now address lifetime measurements in its closest, more neutron deficient, isotone Rh-95 using the same DSAM technique. The experimental results have been interpreted within the framework of large-scale shell-model (LSSM) calculations.
  • Souza, Paulo C. T.; Alessandri, Riccardo; Barnoud, Jonathan; Thallmair, Sebastian; Faustino, Ignacio; Grunewald, Fabian; Patmanidis, Ilias; Abdizadeh, Haleh; Bruininks, Bart M. H.; Wassenaar, Tsjerk A.; Kroon, Peter C.; Melcr, Josef; Nieto, Vincent; Corradi, Valentina; Khan, Hanif M.; Domanski, Jan; Javanainen, Matti; Martinez-Seara, Hector; Reuter, Nathalie; Best, Robert B.; Vattulainen, Ilpo; Monticelli, Luca; Periole, Xavier; Tieleman, D. Peter; de Vries, Alex H.; Marrink, Siewert J. (2021)
    The coarse-grained Martini force field is widely used in biomolecular simulations. Here we present the refined model, Martini 3 (http://cgmartini.nl), with an improved interaction balance, new bead types and expanded ability to include specific interactions representing, for example, hydrogen bonding and electronic polarizability. The updated model allows more accurate predictions of molecular packing and interactions in general, which is exemplified with a vast and diverse set of applications, ranging from oil/water partitioning and miscibility data to complex molecular systems, involving protein-protein and protein-lipid interactions and material science applications as ionic liquids and aedamers.
  • Koivunotko, Elle; Merivaara, Arto; Niemela, Akseli; Valkonen, Sami; Manninen, Kalle; Makinen, Henrik; Viljanen, Mira; Svedstrom, Kirsi; Diaz, Ana; Holler, Mirko; Zini, Jacopo; Paasonen, Lauri; Korhonen, Ossi; Huotari, Simo; Koivuniemi, Artturi; Yliperttula, Marjo (2021)
    The diversity and safety of nanofibrillated cellulose (NFC) hydrogels have gained a vast amount of interest at the pharmaceutical site in recent years. Moreover, this biomaterial has a high potential to be utilized as a protective matrix during the freeze-drying of heat-sensitive pharmaceuticals and biologics to increase their properties for long-term storing at room temperature and transportation. Since freeze-drying and subsequent reconstitution have not been optimized for this biomaterial, we must find a wider understanding of the process itself as well as the molecular level interactions between the NFC hydrogel and the most suitable lyoprotectants. Herein we optimized the reconstitution of the freeze-dried NFC hydrogel by considering critical quality attributes required to ensure the success of the process and gained insights of the obtained experimental data by simulating the effects of the used lyoprotectants on water and NFC. We discovered the correlation between the measured characteristics and molecular dynamics simulations and obtained successful freeze-drying and subsequent reconstitution of NFC hydrogel with the presence of 300 mM of sucrose. These findings demonstrated the possibility of using the simulations together with the experimental measurements to obtain a more comprehensive way to design a successful freeze-drying process, which could be utilized in future pharmaceutical applications.
  • Stenholm, Sari; Ferrucci, Luigi; Vahtera, Jussi; Hoogendijk, Emiel O.; Huisman, Martijn; Pentti, Jaana; Lindbohm, Joni V.; Bandinelli, Stefania; Guralnik, Jack M.; Kivimäki, Mika (2019)
    Background: Frailty is an important geriatric syndrome, but little is known about its development in the years preceding onset of the syndrome. The aim of this study was to examine the progression of frailty and compare the trajectories of each frailty component prior to frailty onset. Methods: Repeat data were from two cohort studies: the Longitudinal Aging Study Amsterdam (n = 1440) with a 15-year follow-up and the InCHIANTI Study (n = 998) with a 9-year follow-up. Participants were classified as frail if they had > 3 frailty components (exhaustion, slowness, physical inactivity, weakness, and weight loss). Transitions between frailty components were examined with multistate modeling. Trajectories of frailty components were compared among persons who subsequently developed frailty to matched nonfrail persons by using mixed effects models. Results: The probabilities were 0.43, 0.40, and 0.36 for transitioning from 0 to 1 frailty component, from 1 component to 2 components, and from 2 components to 3-5 components (the frail state). The transition probability from frail to death was 0.13. Exhaustion separated frail and nonfrail groups already 9 years prior to onset of frailty (pooled risk ratio [RR] = 1.53, 95% confidence interval [CI] 1.04-2.24). Slowness (RR = 1.94, 95% CI 1.44-2.61), low activity (RR = 1.59, 95% CI 1.19-2.13), and weakness (RR = 1.39, 95% CI 1.10-1.76) separated frail and nonfrail groups 6 years prior to onset of frailty. The fifth frailty component, weight loss, separated frail and nonfrail groups only at the onset of frailty (RR = 3.36, 95% CI 2.76-4.08). Conclusions: Evidence from two cohort studies suggests that feelings of exhaustion tend to emerge early and weight loss near the onset of frailty syndrome.
  • Toffol, Elena; Kalleinen, Nea; Himanen, Sari-Leena; Partonen, Timo; Haukka, Jari; Polo-Kantola, Paivi (2021)
    Background: Sleep quality typically decreases after menopause, but the underlying mechanisms are poorly understood. Concentrations of melatonin are lower and its secretion profiles different before and after menopause. However, whether and how melatonin and sleep architecture are associated in women of different reproductive states have not been examined to date. Methods: Overnight serum melatonin samples were taken from 17 perimenopausal and 18 postmenopausal healthy women. Sleep quality was measured with all-night polysomnography recordings. Results: Melatonin concentrations tended to be the lowest during NREM sleep, and were associated with higher odds of transitions from wake to NREM sleep. The curves of predicted overnight melatonin values from linear mixed models varied according to sleep phases (NREM, REM, Wake) in perimenopausal, but not in postmenopausal women. In perimenopause higher melatonin area under curve (AUC) correlated with higher slow-wave activity (p = 0.043), and higher minimum concentrations with shorter slow-wave sleep (SWS) latency (p = 0.029). In postmenopause higher mean and maximum melatonin concentrations and AUC correlated with lower SWS percentage (p = 0.044, p = 0.029, p = 0.032), and higher mean (p = 0.032), maximum (p = 0.032) and minimum (p = 0.037) concentrations with more awakenings from REM sleep. In the age- and BMI-adjusted regression models, the association between higher maximum (p = 0.046) melatonin concentration and lower SWS percentage remained. Conclusions: The relationship between melatonin and sleep architecture differed in perimenopausal and postmenopausal women. After menopause, high melatonin concentrations were associated with worse sleep. Whether these different patterns are related to aging of the reproductive system, and to decrease in menopausal sleep quality, remains to be elucidated. (c) 2021 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
  • Pitkänen, Joonas; Remes, Hanna; Moustgaard, Heta; Martikainen, Pekka (2021)
    Socioeconomic disadvantage in childhood is common among youth not in education, employment or training (NEETs). However, the evidence on other adverse childhood experiences as determinants of NEET remains scarce. We use Finnish longitudinal register data on a 20% random sample of households with 0-14-year-old children in 2000 to assess the childhood determinants of NEET. For an analytical sample of 99,137 children born 1986-1993, family socioeconomic resources, parental psychiatric disorders and substance abuse, parental death, living in a single-parent household and out-of-home placement under age 13 were used to predict NEET at the age of 18. We show that family socioeconomic disadvantage is strongly associated with NEET (e.g. odds ratio for parental basic education 5.33, 95% confidence interval 4.77, 5.95), whereas associations between adverse childhood experiences and NEET are more moderate (e.g. odds ratio for parent hospitalised for psychiatric disorder 1.86, 95% confidence interval 1.63, 2.12) and largely explained by socioeconomic factors. These associations were mostly similar by gender. The results suggest that parental socioeconomic resources are more important than adverse childhood experiences for the educational and employment transitions of young adults. Thus, supportive social policy for socioeconomically disadvantaged families may smooth these transitions.
  • Forma, Leena Päivikki; Aaltonen, Mari; Raitanen, Jani; Anthun, Kjartan Sarheim; Kalseth, Jorid (2020)
    Aims: This study aimed to find out how place of death varied between countries with different health and social service systems. This was done by investigating typical groups (concerning age, sex and end-of-life trajectory) of older people dying in different places in Finland and Norway. Methods: The data were derived from national registers. All those who died in Finland or Norway at the age of ⩾70 years in 2011 were included. Place of death was analysed by age, sex, end-of-life trajectory and degree of urbanisation of the municipality of residence. Two-proportion z-tests were performed to test the differences between the countries. Multinomial logistic regression analyses were performed separately for both countries to find the factors associated with place of death. Results: The data consisted of 68,433 individuals. Deaths occurred most commonly in health centres in Finland and in nursing homes in Norway. Deaths in hospital were more common in Norway than they were in Finland. In both countries, deaths in hospital were more common among younger people and men. Deaths in nursing homes were commonest among frail older people, while most of those who had a terminal illness died in health centres in Finland and in nursing homes in Norway. Conclusions: Both Finland and Norway have a relatively low share of hospital deaths among older people. Both countries have developed alternatives to end-of-life care in hospital, allowing for spending the last days or weeks of life closer to home. In Finland, health centres play a key role in end-of-life care, while in Norway nursing homes serve this role.
  • Olzynska, Agnieszka; Kulig, Waldemar; Mikkolainen, Heikki; Czerniak, Tomasz; Jurkiewicz, Piotr; Cwiklik, Lukasz; Rog, Tomasz; Hof, Martin; Jungwirth, Pavel; Vattulainen, Ilpo (2020)
    Cholesterol renders mammalian cell membranes more compact by reducing the amount of voids in the membrane structure. Because of this, cholesterol is known to regulate the ability of cell membranes to prevent the permeation of water and water-soluble molecules through the membranes. Meanwhile, it is also known that even seemingly tiny modifications in the chemical structure of cholesterol can lead to notable changes in membrane properties. The question is, how significantly do these small changes in cholesterol structure affect the permeability barrier function of cell membranes? In this work, we applied fluorescence methods as well as atomistic molecular dynamics simulations to characterize changes in lipid membrane permeability induced by cholesterol oxidation. The studied 7 beta-hydroxycholesterol (7 beta-OH-chol) and 27-hydroxycholesterol (27-OH-chol) represent two distinct groups of oxysterols, namely, ring- and tail-oxidized cholesterols, respectively. Our previous research showed that the oxidation of the cholesterol tail has only a marginal effect on the structure of a lipid bilayer; however, oxidation was found to disturb membrane dynamics by introducing a mechanism that allows sterol molecules to move rapidly back and forth across the membranebobbing. Herein, we show that bobbing of 27-OH-chol accelerates fluorescence quenching of NBD-lipid probes in the inner leaflet of liposomes by dithionite added to the liposomal suspension. Systematic experiments using fluorescence quenching spectroscopy and microscopy led to the conclusion that the presence of 27-OH-chol increases membrane permeability to the dithionite anion. Atomistic molecular dynamics simulations demonstrated that 27-OH-chol also facilitates water transport across the membrane. The results support the view that oxysterol bobbing gives rise to successive perturbations to the hydrophobic core of the membrane, and these perturbations promote the permeation of water and small water-soluble molecules through a lipid bilayer. The observed impairment of permeability can have important consequences for eukaryotic organisms. The effects described for 27-OH-chol were not observed for 7 beta-OH-chol which represents ring-oxidized sterols.
  • Natri, Heini M.; Merilä, Juha; Shikano, Takahito (2019)
    Sex determination is a fundamentally important and highly diversified biological process, yet the mechanisms behind the origin of this diversity are mostly unknown. Here we suggest that the evolution of sex determination systems can be driven by a chromosomal inversion. We show that an XY system evolved recently in particular nine-spined stickleback (Pungitius pungitius) populations, which arose from ancient hybridization between two divergent lineages. Our phylogenetic and genetic mapping analyses indicate that the XY system is formed in a large inversion that is associated with hybrid sterility between the divergent lineages. We suggest that a new male-determining gene evolved in the inversion in response to selection against impaired male fertility in a hybridized population. Given that inversions are often associated with hybrid incompatibility in animals and plants, they might frequently contribute to the diversification of sex determination systems.