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| 2. |
- Liu, Johan, 1960, et al.
(författare)
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Stem Cell Growth and Migration on Nanofibrous Polymer Scaffolds and Micro-Fluidic Channels on Silicon-Chip
- 2009
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Ingår i: Proceedings of the 2009 Electronic Components and Technology Conference. - 0569-5503. - 9781424444762 ; , s. 1080-1085
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Konferensbidrag (refereegranskat)abstract
- Stem cell growth and migration on nanofibrous scaffolds and micro-fluidic channels on Silicon-Chip were studied by using neural stem cells isolated from adult rats' brain. Electrospinning and lithographic technique were used for developing nanofibrous-polylactic acid (PLA) and polyurethane (PU) based-scaffolds and micro-fluidic channels on Si-Chips respectively. Immunocytochemical and morphological analysis showed better cell-matrix interaction with profound adhesion, proliferation and migration on the developed scaffolds. Cell culture assay with microfluidic channel revealed the ability of developed channel system in guiding neuronal stem cell growth towards specified directions. These studies extend the possibility of using developed nanofibrous scaffolds and micro-fluidic channel system for future electrical signal transmission based on living neural stem cells.
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| 4. |
- Svensson, Johan, 1964, et al.
(författare)
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Liver-derived IGF1 enhances the androgenic response in prostate.
- 2008
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Ingår i: The Journal of endocrinology. - 1479-6805. ; 199:3, s. 489-97
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Tidskriftsartikel (refereegranskat)abstract
- Both IGF1 and androgens are major enhancers of prostate growth and are implicated in the development of prostate hyperplasia and cancer. The aim of the present study was to investigate whether liver-derived endocrine IGF1 modulates the androgenic response in prostate. Mice with adult, liver-specific inactivation of IGF1 (LI-IGF1(-/-) mice) displayed an approximately 80% reduction in serum IGF1 levels associated with decreased prostate weight compared with control mice (anterior prostate lobe -19%, P<0.05; dorsolateral prostate (DLP) lobe -35%, P<0.01; ventral prostate (VP) lobe -47%, P<0.01). Reduced androgen receptor (Ar) mRNA and protein levels were observed in the VP lobe (-34% and -30% respectively, both P<0.05 versus control mice). Analysis of prostate morphology showed reductions in both the glandular and fibromuscular compartments of the VP and DLP lobes that were proportional to the reductions in the weights of these lobes. Immunohistochemistry revealed reduced intracellular AR immunoreactivity in the VP and DLP lobes. The non-aromatizable androgen dihydrotestosterone increased VP weight to a lesser extent in orchidectomized (ORX) LI-IGF1(-/-) mice than in ORX controls (-40%, P<0.05 versus control mice). In conclusion, deficiency of liver-derived IGF1 reduces both the glandular and fibromuscular compartments of the prostate, decreases AR expression in prostate, and reduces the stimulatory effect of androgens on VP weight. These findings may explain, at least in part, the well-known clinical association between serum IGF1 levels and conditions with abnormal prostate growth.
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| 5. |
- Windahl, Sara H, 1971, et al.
(författare)
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Reduced bone mass and muscle strength in male 5α-reductase type 1 inactivated mice.
- 2011
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Ingår i: PloS one. - : Public Library of Science (PLoS). - 1932-6203. ; 6:6
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Tidskriftsartikel (refereegranskat)abstract
- Androgens are important regulators of bone mass but the relative importance of testosterone (T) versus dihydrotestosterone (DHT) for the activation of the androgen receptor (AR) in bone is unknown. 5α-reductase is responsible for the irreversible conversion of T to the more potent AR activator DHT. There are two well established isoenzymes of 5α-reductase (type 1 and type 2), encoded by separate genes (Srd5a1 and Srd5a2). 5α-reductase type 2 is predominantly expressed in male reproductive tissues whereas 5α-reductase type 1 is highly expressed in liver and moderately expressed in several other tissues including bone. The aim of the present study was to investigate the role of 5α-reductase type 1 for bone mass using Srd5a1⁻/⁻ mice. Four-month-old male Srd5a1⁻/⁻ mice had reduced trabecular bone mineral density (-36%, p<0.05) and cortical bone mineral content (-15%, p<0.05) but unchanged serum androgen levels compared with wild type (WT) mice. The cortical bone dimensions were reduced in the male Srd5a1⁻/⁻ mice as a result of a reduced cortical periosteal circumference compared with WT mice. T treatment increased the cortical periosteal circumference (p<0.05) in orchidectomized WT mice but not in orchidectomized Srd5a1⁻/⁻ mice. Male Srd5a1⁻/⁻ mice demonstrated a reduced forelimb muscle grip strength compared with WT mice (p<0.05). Female Srd5a1⁻/⁻ mice had slightly increased cortical bone mass associated with elevated circulating levels of androgens. In conclusion, 5α-reductase type 1 inactivated male mice have reduced bone mass and forelimb muscle grip strength and we propose that these effects are due to lack of 5α-reductase type 1 expression in bone and muscle. In contrast, the increased cortical bone mass in female Srd5a1⁻/⁻ mice, is an indirect effect mediated by elevated circulating androgen levels.
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| 6. |
- Almgren, Torgny, 1962, et al.
(författare)
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Optimization of opportunistic replacement activities: A case study in the aircraft industry
- 2007
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- In the aircraft industry maximizing availability is essential. Maintenance schedules must therefore be opportunistic, incorporating preventive maintenance activities within the scheduled as well as the unplanned ones. At the same time, the maintenance contractor should utilize opportunistic maintenance to enable the minimization of the total expected cost to have a functional aircraft engine and thus to provide attractive service contracts. This paper provides an opportunistic maintenance optimization model which has been constructed and tested together with Volvo Aero Corporation in Trollhättan, Sweden for the maintenance of the RM12 engine. The model incorporates components with deterministic as well as with stochastic lives. The replacement model is shown to have favourable properties; in particular, when the maintenance occasions are fixed the remaining problem has the integrality property, the replacement polytope corresponding to the convex hull of feasible solutions is full-dimensional, and all the necessary constraints for its definition are facet-inducing. We present an empirical crack growth model that estimates the remaining life and also a case study that indicates that a non-stationary renewal process with Weibull distributed lives is a good model for the recurring maintenance occasions. Using one point of support for the distribution yields a deterministic replacement model; it is evaluated against classic maintenance policies from the literature through stochastic simulations. The deterministic model provides maintenance schedules over a finite time period that induce fewer maintenance occasions as well as fewer components replaced.
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| 7. |
- Fries, Johan, et al.
(författare)
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Key parameters for droplet evaporation and mixing at the cloud edge
- 2021
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Ingår i: Quarterly Journal of the Royal Meteorological Society. - : Wiley. - 0035-9009 .- 1477-870X. ; 147:737, s. 2160-2172
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Tidskriftsartikel (refereegranskat)abstract
- The distribution of liquid water in ice-free clouds determines their radiative properties, a significant source of uncertainty in weather and climate models. Evaporation and turbulent mixing cause a cloud to display large variations in droplet number density, but quite small variations in droplet size (Beals et al., Science, 2015, vol. 350, pp. 87-90). However, direct numerical simulations of the joint effect of evaporation and mixing near the cloud edge predict quite different behaviours, and how to reconcile these results with the experimental findings remains an open question. To infer the history of mixing and evaporation from observational snapshots of droplets in clouds is challenging, because clouds are transient systems. We formulated a statistical model that provides a reliable description of the evaporation-mixing process as seen in direct numerical simulations and allows us to infer important aspects of the history of observed droplet populations, highlighting the key mechanisms at work and explaining the differences between observations and simulations.
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| 8. |
- Fries, Johan, et al.
(författare)
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Lagrangian Supersaturation Fluctuations at the Cloud Edge
- 2023
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Ingår i: Physical Review Letters. - : American Physical Society (APS). - 1079-7114 .- 0031-9007. ; 131:25
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Tidskriftsartikel (refereegranskat)abstract
- Evaporation of cloud droplets accelerates when turbulence mixes dry air into the cloud, affecting droplet-size distributions in atmospheric clouds, combustion sprays, and jets of exhaled droplets. The challenge is to model local correlations between droplet numbers, sizes, and supersaturation, which determine supersaturation fluctuations along droplet paths (Lagrangian fluctuations). We derived a statistical model that accounts for these correlations. Its predictions are in quantitative agreement with results of direct numerical simulations, and explain the key mechanisms at play.
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| 9. |
- Hallin, Karl, 1977, et al.
(författare)
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Modelling Information for Mechatronic Products
- 2003
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Ingår i: Proceedings of ICED 03. ; :1331, s. 11-
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Tidskriftsartikel (refereegranskat)abstract
- In mechatronic product development, there is a lack of a common understanding among different engineering domains, regarding the design. One step in improving this situation is to develop information models capable of representing both hardware and software elements. The objective of this paper is to investigate the Chromosome Model’s ability with respect to the mechatronic product and also to suggest an information model which implements its principles. The approach takes its point of departure on a theoretical level by analysing theories from mechanical and software engineering. Further, software concepts of relevance are incorporated into the Chromosome Model. The result, referred to as a meta model, is then transformed to an information model by utilising STEP AP214. Both the meta model and the information model are validated with an industrial example. The conclusions drawn from the work are that the Chromosome Model can be used as a meta model for mechatronic products and that STEP AP214 can be deployed within the scope of the meta model. The resulting information model captures the functional, causal and spatial relationships of a mechatronic product.
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| 10. |
- Jurkeviciute, M., et al.
(författare)
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Identifying the Value of an eHealth Intervention Aimed at Cognitive Impairments: Observational Study in Different Contexts and Service Models
- 2020
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Ingår i: Journal of Medical Internet Research. - : JMIR Publications Inc.. - 1438-8871. ; 22:10
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Tidskriftsartikel (refereegranskat)abstract
- Background: Value is one of the central concepts in health care, but it is vague within the field of summative eHealth evaluations. Moreover, the role of context in explaining the value is underexplored, and there is no explicit framework guiding the evaluation of the value of eHealth interventions. Hence, different studies conceptualize and operationalize value in different ways, ranging from measuring outcomes such as clinical efficacy or behavior change of patients or professionals to measuring the perceptions of various stakeholders or in economic terms. Objective: The objective of our study is to identify contextual factors that determine similarities and differences in the value of an eHealth intervention between two contexts. We also aim to reflect on and contribute to the discussion about the specification, assessment, and relativity of the "value" concept in the evaluation of eHealth interventions. Methods: The study concerned a 6-month eHealth intervention targeted at elderly patients (n=107) diagnosed with cognitive impairment in Italy and Sweden. The intervention introduced a case manager role and an eHealth platform to provide remote monitoring and coaching services to the patients. A model for evaluating the value of eHealth interventions was designed as monetary and nonmonetary benefits and sacrifices, based on the value conceptualizations in eHealth and marketing literature. The data was collected using the Mini-Mental State Examination (MMSE), the clock drawing test, and the 5-level EQ-5D (EQ-5D-5L). Semistructured interviews were conducted with patients and health care professionals. Monetary data was collected from the health care and technology providers. Results: The value of an eHealth intervention applied to similar types of populations but differed in different contexts. In Sweden, patients improved cognitive performance (MMSE mean 0.85, SD 1.62, P<.001), reduced anxiety (EQ-5D-5L mean 0.16, SD 0.54, P=.046), perceived their health better (EQ-5D-5L VAS scale mean 2.6, SD 9.7, P=.035), and both patients and health care professionals were satisfied with the care. However, the Swedish service model demonstrated an increased cost, higher workload for health care professionals, and the intervention was not cost-efficient. In Italy, the patients were satisfied with the care received, and the health care professionals felt empowered and had an acceptable workload. Moreover, the intervention was cost-effective. However, clinical efficacy and quality of life improvements have not been observed. We identified 6 factors that influence the value of eHealth intervention in a particular context: (1) service delivery design of the intervention (process of delivery), (2) organizational setup of the intervention (ie, organizational structure and professionals involved), (3) cost of different treatments, (4) hourly rates of staff for delivering the intervention, (5) lifestyle habits of the population (eg, how physically active they were in their daily life and if they were living alone or with family), and (6) local preferences on the quality of patient care. Conclusions: Value in the assessments of eHealth interventions need to be considered beyond economic terms, perceptions, or behavior changes. To obtain a holistic view of the value created, it needs to be operationalized into monetary and nonmonetary outcomes, categorizing these into benefits and sacrifices.
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