| 1. |
- van Haarlem, M. P., et al.
(author)
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LOFAR : The LOw-Frequency ARray
- 2013
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In: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 556, s. 1-53
-
Journal article (peer-reviewed)abstract
- LOFAR, the LOw-Frequency ARray, is a new-generation radio interferometer constructed in the north of the Netherlands and across europe. Utilizing a novel phased-array design, LOFAR covers the largely unexplored low-frequency range from 10–240 MHz and provides a number of unique observing capabilities. Spreading out from a core located near the village of Exloo in the northeast of the Netherlands, a total of 40 LOFAR stations are nearing completion. A further five stations have been deployed throughout Germany, and one station has been built in each of France, Sweden, and the UK. Digital beam-forming techniques make the LOFAR system agile and allow for rapid repointing of the telescope as well as the potential for multiple simultaneous observations. With its dense core array and long interferometric baselines, LOFAR achieves unparalleled sensitivity and angular resolution in the low-frequency radio regime. The LOFAR facilities are jointly operated by the International LOFAR Telescope (ILT) foundation, as an observatory open to the global astronomical community. LOFAR is one of the first radio observatories to feature automated processing pipelines to deliver fully calibrated science products to its user community. LOFAR’s new capabilities, techniques and modus operandi make it an important pathfinder for the Square Kilometre Array (SKA). We give an overview of the LOFAR instrument, its major hardware and software components, and the core science objectives that have driven its design. In addition, we present a selection of new results from the commissioning phase of this new radio observatory.
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| 2. |
- Astvaldsdottir, A., et al.
(author)
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Oral health and dental care of older persons-A systematic map of systematic reviews
- 2018
-
In: Gerodontology. - : Wiley. - 0734-0664 .- 1741-2358. ; 35:4, s. 290-304
-
Research review (peer-reviewed)abstract
- Objectives: To examine the current knowledge on oral health status and dental care of older persons through a systematic mapping of systematic reviews of low or moderate risk of bias. Background: Geriatric dentistry covers all aspects of oral health and oral care of older persons. Oral health is part of general health and contributes to a person's physical, psychological and social wellbeing. Methods: A literature search was performed in three different databases (PubMed, The Cochrane Library and Cinahl) within 12 domains: Dental caries, periodontitis, Orofacial pain and temporomandibular joint (TMJ) pain, mucosal lesions, oral motor function, dry mouth, halitosis, interaction between oral status and other medical conditions, ability to interrelate and communicate, quality of life, ethics and organisation of dental care for older persons. Systematic reviews were identified and scrutinised, highlighting scientific knowledge and knowledge gaps. Results: We included 32 systematic reviews of which 14 were judged to be of low/moderate risk of bias. Most of the domains lack systematic reviews with low or moderate risk of bias. In two of the domains evidence was identified; in institutionalised people aged 65 or older, effective oral hygiene can prevent pneumonia. Furthermore, there is an evidence of a relationship between malnutrition (protein energy-related malnutrition, PEM) and poor appetite and edentulousness. Conclusions: There is an urgent need for further research and evidence-based knowledge within most domains in geriatric dentistry and in other fields related to oral health and dental care for older persons striving for multi-disciplinary research programmes.
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| 3. |
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| 4. |
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| 5. |
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| 6. |
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| 7. |
- Stanciu, V., et al.
(author)
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Influence of annealing parameters on the ferromagnetic properties of optimally passivated (Ga,Mn)As epilayers
- 2005
-
In: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 72:12
-
Journal article (peer-reviewed)abstract
- The influence of annealing parameters—temperature (Ta) and time (ta)—on the magnetic properties of As-capped (Ga,Mn)As epitaxial thin films has been investigated. The dependence of the transition temperature (TC) on ta marks out two regions. The TC peak behavior, characteristic of the first region, is more pronounced for thick samples, while for the second ("saturated") region the effect of ta is more pronounced for thin samples. A right choice of the passivation medium, growth conditions along with optimal annealing parameters routinely yield TC-values of ~150 K and above, regardless of the thickness of the epilayers
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| 8. |
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| 9. |
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| 10. |
- Banchelli, M., et al.
(author)
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Phospholipid membranes decorated by cholesterol-based oligonucleotides as soft hybrid nanostructures
- 2008
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In: Journal of Physical Chemistry B. - : American Chemical Society (ACS). - 1520-5207 .- 1520-6106. ; 112:35, s. 10942-10952
-
Journal article (peer-reviewed)abstract
- DNA monomers and oligomers are currently showing great promise as building blocks for supramolecular arrays that can self-assemble in a fashion preprogrammed by the base pairing code. The design and build-up of hybrid DNA/amphiphilic self-assemblies can expand the range of possible architectures and enhance the selectivity toward a well-specified geometry. We report on the self-assembly properties in aqueous solution of a cholesteryl-tetraethylenglycol single stranded 18-mer oligonucleotide (ON(1)TEG-Chol) and on its spontaneous insertion in fluid phospholipid membranes. Up to 500 units of these lipophilic ss-oligonucleotides can be incorporated in the outer leaflet of 350 A radius POPC vesicle. The insertion and hybridization with the complementary oligonucleotide are monitored through light scattering as an increase of hydrodynamic thickness, which is interpreted in terms of average distance between anchoring sites. The conformation of the ss-oligonucleotidic portion is strongly dependent on surface coverage, passing from a quasi-random coil to a more rigid configuration, as concentration increases. Interestingly, conformational details affect in a straightforward fashion the hybridization kinetics. Liposomes with single- and double-strand decorations remain stable within the experimental time window (about one week). The structure represents an example of successful and stable amphiphile/DNA supramolecular hybrid, where a DNA guest is held in a membrane by hydrophobic interactions. The lipophilic oligonucleotide under investigation is therefore a suitable building block that can effectively serve as a hydrophobic anchor in the fluid bilayer to assemble supramolecular constructs based on the DNA digital code.
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| 11. |
- Dumat, Blaise, 1984, et al.
(author)
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Second-Generation Fluorescent Quadracyclic Adenine Analogues: Environment-Responsive Probes with Enhanced Brightness
- 2015
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In: Chemistry - A European Journal. - : Wiley. - 0947-6539 .- 1521-3765. ; 21:10, s. 4039-4048
-
Journal article (peer-reviewed)abstract
- Fluorescent base analogues comprise a group of increasingly important molecules for the investigation of nucleic acid structure, dynamics, and interactions with other molecules. Herein, we report on the quantum chemical calculation aided design, synthesis, and characterization of four new putative quadracyclic adenine analogues. The compounds were efficiently synthesized from a common intermediate through a two-step pathway with the Suzuki-Miyaura coupling as the key step. Two of the compounds, qAN1 and qAN4, display brightnesses (εΦF) of 1700 and 2300, respectively, in water and behave as wavelength-ratiometric pH probes under acidic conditions. The other two, qAN2 and qAN3, display lower brightnesses but exhibit polarity-sensitive dual-band emissions that could prove useful to investigate DNA structural changes induced by DNA-protein or -drug interactions. The four qANs are very promising microenvironment-sensitive fluorescent adenine analogues that display considerable brightness for such compounds. Polarity and pH probes: 2-Aminopurine has long been the standard for fluorescent base analogues. Four new fluorescent probes suitable for the replacement of adenine in nucleic acids are presented. Based on their high structural similarity to their parent compound, quadracyclic adenine, they have the potential to be excellent A analogues. Their improved photophysical properties also suggest that they could be significantly brighter than 2-aminopurine inside nucleic acid systems (see figure; ΦF: fluorescence quantum yield).
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| 12. |
- Grosche, A., et al.
(author)
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Versatile and Simple Approach to Determine Astrocyte Territories in Mouse Neocortex and Hippocampus
- 2013
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In: Plos One. - : Public Library of Science (PLoS). - 1932-6203. ; 8:7
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Journal article (peer-reviewed)abstract
- Background: Besides their neuronal support functions, astrocytes are active partners in neuronal information processing. The typical territorial structure of astrocytes (the volume of neuropil occupied by a single astrocyte) is pivotal for many aspects of glia-neuron interactions. Methods: Individual astrocyte territorial volumes are measured by Golgi impregnation, and astrocyte densities are determined by S100 beta immunolabeling. These data are compared with results from conventionally applied methods such as dye filling and determination of the density of astrocyte networks by biocytin loading. Finally, we implemented our new approach to investigate age-related changes in astrocyte territories in the cortex and hippocampus of 5- and 21-month-old mice. Results: The data obtained by our simplified approach based on Golgi impregnation were compared to previously published dye filling experiments, and yielded remarkably comparable results regarding astrocyte territorial volumes. Moreover, we found that almost all coupled astrocytes (as indicated by biocytin loading) were immunopositive for S100 beta. A first application of this new experimental approach gives insight in age-dependent changes in astrocyte territorial volumes. They increased with age, while cell densities remained stable. In 5-month-old mice, the overlap factor was close to 1, revealing little or no interdigitation of astrocyte territories. However, in 21-month-old mice, the overlap factor was more than 2, suggesting that processes of adjacent astrocytes interdigitate. Conclusion: Here we verified the usability of a simple, versatile method for assessing astrocyte territories and the overlap factor between adjacent territories. Second, we found that there is an age-related increase in territorial volumes of astrocytes that leads to loss of the strict organization in non-overlapping territories. Future studies should elucidate the physiological relevance of this adaptive reaction of astrocytes in the aging brain and the methods presented in this study might be a powerful tool to do so.
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| 13. |
- Håversen, Liliana, 1963, et al.
(author)
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Vimentin deficiency in macrophages induces increased oxidative stress and vascular inflammation but attenuates atherosclerosis in mice
- 2018
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In: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 8
-
Journal article (peer-reviewed)abstract
- The aim was to clarify the role of vimentin, an intermediate filament protein abundantly expressed in activated macrophages and foam cells, in macrophages during atherogenesis. Global gene expression, lipid uptake, ROS, and inflammation were analyzed in bone-marrow derived macrophages from vimentin-deficient (Vim(-/-)) and wild-type (Vim(-/-)) mice. Atherosclerosis was induced in Ldlr(-/-) mice transplanted with a PCSK9 gain-of-function virus. The mice were fed an atherogenic diet for 12-15 weeks. We observed impaired uptake of native LDL but increased uptake of oxLDL in Vim(-/-) macrophages. FACS analysis revealed increased surface expression of the scavenger receptor CD36 on Vim(-/-) macrophages. Vim(-/-) macrophages also displayed increased markers of oxidative stress, activity of the transcription factor NF-kappa B, secretion of proinflammatory cytokines and GLUT1-mediated glucose uptake. Vim(-/- )mice displayed decreased atherogenesis despite increased vascular inflammation and increased CD36 expression on macrophages in two mouse models of atherosclerosis. We demonstrate that vimentin has a strong suppressive effect on oxidative stress and that Vim(-/-) mice display increased vascular inflammation with increased CD36 expression on macrophages despite decreased subendothelial lipid accumulation. Thus, vimentin has a key role in regulating inflammation in macrophages during atherogenesis.
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| 14. |
- Högberg, Hans, 1968-, et al.
(author)
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Growth and characterization of MAX-phase thin films
- 2005
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In: Surface and Coatings Technology. - : Elsevier BV. - 0257-8972 .- 1879-3347. ; 193, s. 6-10
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Journal article (peer-reviewed)abstract
- We report that magnetron sputtering can be applied to synthesize MAX-phase films of several systems including Ti–Si–C, Ti–Ge–C, Ti–Al–C, and Ti–Al–N. In particular, epitaxial films of the known phases Ti3SiC2, Ti3GeC2, Ti2GeC, Ti3AlC2, Ti2AlC, and Ti2AlN as well as the newly discovered thin film phases Ti4SiC3, Ti4GeC3 and intergrown structures can be deposited at 900–1000 °C on Al2O3(0001) and MgO(111) pre-seeded with TiC or Ti(Al)N. From XTEM and AFM we suggest a growth and nucleation model where MAX-phase nucleation is initiated at surface steps or facets on the seed layer and followed by lateral growth. Differences between the growth behavior of the systems with respect to phase distribution and phase stabilities are discussed. Characterization of mechanical properties for Tin+1Si–Cn films with nanoindentation show decreased hardness from about 25 to 15 GPa upon penetration of the basal planes with characteristic large plastic deformation with pile up dependent on the choice of MAX material. This is explained by cohesive delamination of the basal planes and kink band formation, in agreement with the observations made for bulk material. Measurements of the electrical resistivity for Ti–Si–C and Ti–Al–N films with four-point probe technique show values of 30 and 39 μΩ cm, respectively, comparable to bulk materials.
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| 15. |
- Khorram-Manesh, Amir, 1958, et al.
(author)
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Non-medical aspects of civilian-military collaboration in management of major incidents.
- 2017
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In: European journal of trauma and emergency surgery : official publication of the European Trauma Society. - : Springer Science and Business Media LLC. - 1863-9941. ; 43:5, s. 595-603
-
Journal article (peer-reviewed)abstract
- Disasters and major incidents demand a multidisciplinary management. Recent experiences from terrorist attacks worldwide have resulted in a search for better assessment of the needs, resources, and knowledge in the medical and non-medical management of these incidents and also actualized the need for collaboration between civilian and military healthcare. The aim of this study was to evaluate the impact of the civilian-military collaboration in a Swedish context with the main focus on its non-medical management.An exercise, simulating a foreign military attack centrally on Swedish soil, was designed, initiated, and conducted by a team consisting of civilian and military staff. Data were collected prospectively and evaluated by an expert team.Specific practical and technical issues were presented in collaboration between civilian and military staffs. In addition, shortcomings in decision-making, follow-up, communication, and collaboration due to prominent lack of training and exercising the tasks and positions in all managerial levels of the hospital were identified.Current social and political unrests and terror attacks worldwide necessitate civilian-military collaboration. Such collaboration, however, needs to be synchronized and adjusted to avoid preventable medical and non-medical consequences. Simulation exercises might be one important source to improve such collaboration.
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| 16. |
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| 17. |
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| 18. |
- Li, Lizhen, 1977, et al.
(author)
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Protective role of reactive astrocytes in brain ischemia.
- 2008
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In: Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism. - : SAGE Publications. - 0271-678X .- 1559-7016. ; 28:3, s. 468-81
-
Journal article (peer-reviewed)abstract
- Reactive astrocytes are thought to protect the penumbra during brain ischemia, but direct evidence has been lacking due to the absence of suitable experimental models. Previously, we generated mice deficient in two intermediate filament (IF) proteins, glial fibrillary acidic protein (GFAP) and vimentin, whose upregulation is the hallmark of reactive astrocytes. GFAP(-/-)Vim(-/-) mice exhibit attenuated posttraumatic reactive gliosis, improved integration of neural grafts, and posttraumatic regeneration. Seven days after middle cerebral artery (MCA) transection, infarct volume was 210 to 350% higher in GFAP(-/-)Vim(-/-) than in wild-type (WT) mice; GFAP(-/-), Vim(-/-) and WT mice had the same infarct volume. Endothelin B receptor (ET(B)R) immunoreactivity was strong on cultured astrocytes and reactive astrocytes around infarct in WT mice but undetectable in GFAP(-/-)Vim(-/-) astrocytes. In WT astrocytes, ET(B)R colocalized extensively with bundles of IFs. GFAP(-/-)Vim(-/-) astrocytes showed attenuated endothelin-3-induced blockage of gap junctions. Total and glutamate transporter-1 (GLT-1)-mediated glutamate transport was lower in GFAP(-/-)Vim(-/-) than in WT mice. DNA array analysis and quantitative real-time PCR showed downregulation of plasminogen activator inhibitor-1 (PAI-1), an inhibitor of tissue plasminogen activator. Thus, reactive astrocytes have a protective role in brain ischemia, and the absence of astrocyte IFs is linked to changes in glutamate transport, ET(B)R-mediated control of gap junctions, and PAI-1 expression.
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| 19. |
- Lindh, T, et al.
(author)
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Tooth-implant supported fixed prostheses : A retrospective multicenter study
- 2001
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In: International Journal of Prosthodontics. - 0893-2174 .- 1139-9791. ; 14:4, s. 321-328
-
Journal article (peer-reviewed)abstract
- Purpose: The purpose of this retrospective multicenter study on implants combined with natural teeth was to investigate the implant survival rate and loss of marginal bone, as well as indications and complications pertinent to this form of implant therapy. Materials and Methods: The study comprised 185 implants in 111 patients from six different clinics in Sweden. Gathering of data, which were taken from patient records, followed a strict protocol. The registrations included indications for treatment, failure of implants, radiographs from baseline and follow-up, and information on complications. Results: The cumulative implant survival was found to be 95.4% (standard error 4.5%) up to 3 years of follow-up. The marginal bone level at baseline was lower in the maxilla compared with the mandible (P = .015), but any further loss did not differ between the jaws. The most severe complication other than loss of osseointegration (6/185) or periimplant infections (4/183) was intrusion of the abutment teeth, which occurred in 5% of the cases. In all instances, the intrusion was seen in constructions with nonrigid forms of connection between the implants and teeth. Conclusion: The tooth-implant supported prosthesis using the Branemark system is in the short term an equally predictable treatment as the completely implant-supported prosthesis concerning implant survival and loss of marginal bone. When combining implants and teeth, a rigid form of connection should be used to prevent tooth intrusion.
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| 20. |
- Magnuson, Martin, et al.
(author)
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Electronic structure and chemical bonding in Ti2AlC investigated by soft x-ray emission spectroscopy
- 2006
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In: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 74:195108
-
Journal article (peer-reviewed)abstract
- Theelectronic structure of the nanolaminated transition metal carbide Ti2AlC hasbeen investigated by bulk-sensitive soft x-ray emission spectroscopy. The measuredTi L, C K, and Al L emission spectra arecompared with calculated spectra using ab initio density-functional theory includingdipole matrix elements. The detailed investigation of the electronic structureand chemical bonding provides increased understanding of the physical propertiesof this type of nanolaminates. Three different types of bondregions are identified: The relatively weak Ti 3d–Al 3p bond1 eV below the Fermi level and the Ti 3d–C 2pand Ti 3d–C 2s bonds which are stronger and deeperin energy are observed around 2.5 and 10 eV below theFermi level, respectively. A strongly modified spectral shape of the3s final states in comparison to pure Al is detectedfor the intercalated Al monolayers indirectly reflecting the Ti 3d–Al3p hybridization. The differences between the electronic and crystal structuresof Ti2AlC, Ti3AlC2, and TiC are discussed in relation tothe number of Al layers per Ti layer in thetwo former systems and the corresponding change of the unusualmaterials properties.
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| 21. |
- Nakazawa, Toru, et al.
(author)
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Attenuated glial reactions and photoreceptor degeneration after retinal detachment in mice deficient in glial fibrillary acidic protein and vimentin.
- 2007
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In: Investigative ophthalmology & visual science. - : Association for Research in Vision and Ophthalmology (ARVO). - 0146-0404 .- 1552-5783. ; 48:6, s. 2760-8
-
Journal article (peer-reviewed)abstract
- PURPOSE: To characterize the reactions of retinal glial cells (astrocytes and Müller cells) to retinal injury in mice that lack glial fibrillary acidic protein (GFAP) and vimentin (GFAP-/-Vim-/-) and to determine the role of glial cells in retinal detachment (RD)-induced photoreceptor degeneration. METHODS: RD was induced by subretinal injection of sodium hyaluronate in adult wild-type (WT) and GFAP-/-Vim-/- mice. Astroglial reaction and subsequent monocyte recruitment were quantified by measuring extracellular signal-regulated kinase (Erk) and c-fos activation and the level of expression of chemokine monocyte chemoattractant protein (MCP)-1 and by counting monocytes/microglia in the detached retinas. Immunohistochemistry, immunoblotting, real-time quantitative polymerase chain reaction (PCR), and enzyme-linked immunosorbent assay (ELISA) were used. RD-induced photoreceptor degeneration was assessed by terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) and measurement of outer nuclear layer (ONL) thickness. RESULTS: RD-induced reactive gliosis, characterized by GFAP and vimentin upregulation, Erk and c-fos activation, MCP-1 induction, and increased monocyte recruitment in WT mice. Absence of GFAP and vimentin effectively attenuated reactive responses of retinal glial cells and monocyte infiltration. As a result, detached retinas of GFAP-/-Vim-/- mice exhibited significantly reduced numbers of TUNEL-positive photoreceptor cells and increased ONL thickness compared with those of WT mice. CONCLUSIONS: The absence of GFAP and vimentin attenuates RD-induced reactive gliosis and, subsequently, limits photoreceptor degeneration. Results of this study indicate that reactive retinal glial cells contribute critically to retinal damage induced by RD and provide a new avenue for limiting photoreceptor degeneration associated with RD and other retinal diseases or damage.
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| 22. |
- Olsson, Pål Axel, et al.
(author)
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The growth of external AM fungal mycelium in sand dunes and in experimental systems
- 2000
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In: Plant and Soil. - 0032-079X. ; 226:2, s. 161-169
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Journal article (peer-reviewed)abstract
- We estimated the biomass and growth of arbuscular mycorrhizal (AM) mycelium in sand dunes using signature fatty acids. Mesh bags and tubes, containing initially mycelium-free sand, were buried in the field near the roots of the dune grass Ammophila arenaria L. AM fungal mycelia were detected at a distance of about 8.5 cm from the roots after 68 days of growth by use of neutral lipid fatty acid (NLFA) 16:15. The average rate of mycelium extension during September and October was estimated as 1.2 mm day–1. The lipid and fatty acid compositions of AM fungal mycelia of isolates and from sand dunes were analysed and showed all to be of a similar composition. Phospholipid fatty acids (PLFAs) can be used as indicators of microbial biomass. The mycelium of G. intraradices growing in glass beads contained 8.3 nmol PLFAs per mg dry biomass, and about 15% of the PLFAs in G. intraradices, G. claroideum and AM fungal mycelium extracted from sand dunes, consisted of the signature PLFA 16:15. We thus suggest a conversion factor of 1.2 nmol PLFA 16:15 per mg dry biomass. Calculations using this conversion factor indicated up to 34 g dry AM fungal biomass per g sand in the sand dunes, which was less than one tenth of that found in an experimental system with Glomus spp. growing with cucumber as plant associate in agricultural soil. The PLFA results from different systems indicated that the biomass of the AM fungi constitutes a considerable part of the total soil microbial biomass. Calculations based on ATP of AM fungi in an experimental growth system indicated that the biomass of the AM fungi constituted approximately 30% of the total microbial biomass.
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| 23. |
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| 24. |
- Rydén, L, et al.
(author)
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A Double-Blind Trial of Metoprolol in Acute Myocardial Infarction : Effects on Ventricular Tachyarrhythmias
- 1983
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In: New England Journal of Medicine. - : Massachusetts Medical Society. - 0028-4793 .- 1533-4406. ; 308:11, s. 614-618
-
Journal article (peer-reviewed)abstract
- During a double-blind trial in which patients with suspected myocardial infarction received metoprolol or placebo, we analyzed the occurrence of ventricular tachyarrhythmias. Metoprolol (15 mg intravenously) was given as soon as possible after admission, and thereafter 200 mg was given daily for three months. Antiarrhythmic drugs were given only for ventricular fibrillation and sustained ventricular tachycardia (greater than 60 beats per second). Definite acute myocardial infarction developed in 809 of the 1395 participants, and probable infarction in 162. Metoprolol did not influence the occurrence of premature ventricular contractions or short bursts of ventricular tachycardia. However, there were 17 cases of ventricular fibrillation in the placebo group (697 patients) and only 6 in the metoprolol group (698 patients, P less than 0.05). During the hospital stay significantly fewer patients receiving metoprolol (16) than placebo (38) (P less than 0.01) required lidocaine. In a separate analysis of 145 patients, metoprolol did not influence the occurrence of premature ventricular contractions or short bursts of ventricular tachycardia during the first 24 hours of treatment. Despite a lack of effect on less serious ventricular tachyarrhythmias, metoprolol had a prophylactic effect against ventricular fibrillation in acute myocardial infarction.
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| 25. |
- Saarnio, Ville K., et al.
(author)
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Development of functionalized SYBR green II related cyanine dyes for viral RNA detection
- 2020
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In: Dyes and Pigments. - : Elsevier BV. - 0143-7208 .- 1873-3743. ; 177
-
Journal article (peer-reviewed)abstract
- Fluorescent probes for sensing nucleic acids have found widespread use in the field of cell and molecular biology. However, probes combined with potential for post-synthetic conjugation, e.g. for intra-endosomal measurements of RNA, are unavailable. Herein we developed cyanine dyes that can be conjugated to viral capsid or other targets. First, we solved the crystal structure of SYBR Green II. The structural elucidation of this commonly used RNA probe provided the basis for synthesizing similar molecules with much desired function for post-synthetic conjugation. To address this need, cyanine dyes were prepared using an alternative synthesis protocol. All studied compounds showed considerable brightness upon binding to nucleic acids. However, regardless of the common chromophore on the dyes, the observed fluorescence emission intensities varied significantly, where methyl-substituted dye 1 gave values higher than SYBR Green II, whereas compounds 2–5 containing undecyl spacers had lower values. Studying the structure-activity relationship revealed the longer alkyl chains to induce slight perturbation in dye intercalation, as well as demand larger binding area on the nucleic acid lattice, explaining these differences. To study the potential biological use of the dyes, the RNA genome of enterovirus echovirus 1 was studied in vitro with the probes. A novel method employing the low binding space requirement of 1 was developed to determine the single-to-double-stranded RNA ratio of a sample, whereas compound 4 was covalently bound to the viral capsid and used successfully to monitor the viral RNA release from within the capsid. The presented results open new possibilities for preparation and use of SYBR Green-based nucleic acid probes to further apply these compounds for increasingly demanding targeting in biological contexts.
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| 26. |
- Shukla, G. C., et al.
(author)
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A Boost for the Emerging Field of RNA Nanotechnology - Report on the First International conference on RNA Nanotechnology
- 2011
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In: ACS Nano. - : American Chemical Society (ACS). - 1936-086X .- 1936-0851. ; 5:5, s. 3405-3418
-
Journal article (peer-reviewed)abstract
- This Nano Focus article highlights recent advances in RNA nanotechnology as presented at the First International Conference of RNA Nanotechnology and Therapeutics, which took place in Cleveland, OH, USA (October 23-25, 2010) (http;//www.eng.uc.edu/nanomedidne/RNA2010/), chaired by Peixuan Guo and co-chaired by David Rueda and Scott Tenenbaum. The conference was the first of its kind to bring together more than 30 invited speakers in the frontier of RNA nanotechnology from France, Sweden, South Korea, China, and throughout the United States to discuss RNA nanotechnology and Its applications. It provided a platform for researchers from academia, government, and the pharmaceutical industry to share existing knowledge, vision, technology, and challenges in the field and promoted collaborations among researchers interested in advancing this emerging scientific discipline. The meeting covered a range of topics, including biophysical and single-molecule approaches for characterization of RNA nanostructures; structure studies on RNA nanoparticles by chemical or biochemical approaches, computation, prediction, and modeling of RNA nanoparticle structures; methods for the assembly of RNA nanoparticles; chemistry for RNA synthesis, conjugation, and labeling; and application of RNA nanoparticles in therapeutics. A special invited talk on the well-established principles of DNA nanotechnology was arranged to provide models for RNA nanotechnology. An Administrator from National Institutes of Health (NIH) National Cancer Institute (NCI) Alliance for Nanotechnology in Cancer discussed the current nanocancer research directions and future funding opportunities at NCl. As indicated by the feedback received from the invited speakers and the meeting participants, this meeting was extremely successful, exciting, and informative, covering many groundbreaking findings, pioneering ideas, and novel discoveries.
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| 27. |
- Sjögren, Torsten, et al.
(author)
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High Performance Piston Rings for Two-Stroke Marine Diesel Engines
- 2004
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In: Proceedings // 24th CIMAC World Congress on Combustion Engine Technology.
-
Conference paper (other academic/artistic)abstract
- The piston ring is a key component in a marine combustion engine. High mechanical loads, relatively high temperatures and corrosive gases and liquids influence its performance in terms of sealing capacity, wear of cylinder liner and the ring itself. Base material of the ring, coating technology and ring geometry design are discussed in the article.When tailoring cast iron materials suitable as piston ring base material two parameters are of importance; the morphology of the graphite and the constituents of the matrix. To optimize the properties of the cast iron a compromise is needed to achieve a satisfactory performance of the piston rings.Daros Piston Rings AB is currently developing a second generation of chromium-ceramic coating the so called Z-chrome. The objective of this project has been to increase the maximum operating temperature of the coating and leave the other characteristics of the coating unaffected. The difference between the commercial Daros coating Tritor® and the Z-chrome is the ceramic component included in the coated layer.Insufficient conformability of piston ring and liner geometry may produce a large local cylinder wall pressure which will destroy the oil film leading to uncontrolled wear and scuffing. Lack of conformability can also produce leakage paths for the combustion gases. Therefore a correct ring shape is of utmost importance. A new design philosophy designated OPCORE® has been developed and is presented here.
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| 28. |
- Stengel, Gudrun, et al.
(author)
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Conformational dynamics of DNA polymerase probed with a novel fluorescent DNA base analogue
- 2007
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In: Biochemistry. - : American Chemical Society (ACS). - 1520-4995 .- 0006-2960. ; 46:43, s. 12289-12297
-
Journal article (peer-reviewed)abstract
- DNA polymerases discriminate between correct and incorrect nucleotide substrates during a "nonchemical" step that precedes phosphodiester bond formation in the enzymatic cycle of nucleotide incorporation. Despite the importance of this process in polymerase fidelity, the precise nature of the molecular events involved remains unknown. Here we report a fluorescence resonance energy transfer (FRET) system that monitors conformational changes of a polymerase-DNA complex during selection and binding of nucleotide substrates. This system utilizes the fluorescent base analogue 1,3-diaza-2oxophenothiazine (tC) as the FRET donor and Alexa-555 (A555) as the acceptor. The tC donor was incorporated within a model DNA primer/template in place of a normal base, adjacent to the primer 3' terminus, while the A555 acceptor was attached to an engineered cysteine residue (C751) located in the fingers subdomain of the Klenow fragment (KF) polymerase. The FRET efficiency increased significantly following binding of a correct nucleotide substrate to the KF-DNA complex, showing that the fingers had closed over the active site. Fluorescence anisotropy titrations utilizing tC as a reporter indicated that the DNA was more tightly bound by the polymerase under these conditions, consistent with the formation of a closed ternary complex. The rate of the nucleotide-induced conformational transition, measured in stopped-flow FRET experiments, closely matched the rate of correct nucleotide incorporation, measured in rapid quench-flow experiments, indicating that the conformational change was the rate-limiting step in the overall cycle of nucleotide incorporation for the labeled KF-DNA system. Taken together, these results indicate that the FRET system can be used to probe enzyme conformational changes that are linked to the biochemical function of DNA polymerase.
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| 29. |
- Tumpane, John, 1983, et al.
(author)
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Addressable high-information-density DNA nanostructures
- 2007
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In: Chemical Physics Letters. - : Elsevier BV. - 0009-2614. ; 440:1-3, s. 125-129
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Journal article (peer-reviewed)abstract
- We present a strategy for self-assembly of the smallest yet reported DNA nanostructures that are also addressable in terms of their DNA-base code. Using linear as well as novel branched three-way DNA., oligonucleotide building-blocks we demonstrate the formation of a nano-network's fundamental cell, a DNA pseudo-hexagon of side 4 nm. The network's inherent addressability will allow functionalization with sub-nanometer precision yielding unprecedented richness in information density, important in the context of Moore's Law and nano-chip technology. (c) 2007 Published by Elsevier B.V.
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| 30. |
- Verardo, Mark R, et al.
(author)
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Abnormal reactivity of muller cells after retinal detachment in mice deficient in GFAP and vimentin.
- 2008
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In: Investigative ophthalmology & visual science. - : Association for Research in Vision and Ophthalmology (ARVO). - 1552-5783. ; 49:8, s. 3659-65
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Journal article (peer-reviewed)abstract
- PURPOSE: To determine the roles of glial fibrillary acidic protein (GFAP) and vimentin in M?ller cell reactivity. METHODS: Retinal detachments were created in mice deficient for GFAP and vimentin (GFAP(-/-)vim(-/-)) and age-matched wild-type (wt) mice. The reactivity of the retina was studied by immunofluorescence and electron microscopy. RESULTS: M?ller cell morphology was different and glutamine synthetase immunoreactivity was reduced in the undisturbed GFAP(-/-)vim(-/-) retinas. After retinal detachment, M?ller cells formed subretinal glial scars in the wt mice. In contrast, such scars were not observed in GFAP(-/-)vim(-/-) mice. M?ller cells, which normally elongate and thicken in response to detachment, appeared compressed, thin, and "spikey" in the GFAP(-/-)vim(-/-) mice. The end foot region of M?ller cells in the GFAP(-/-)vim(-/-) mice often sheared away from the rest of the retina during detachment, corroborating earlier results showing decreased resistance of this region in GFAP(-/-)vim(-/-) retinas to mechanical stress. In regions with end foot shearing, ganglion cells showed intense neurite sprouting, as revealed by anti-neurofilament labeling, a response rarely observed in wt mice. CONCLUSIONS: M?ller cells are subtly different in the GFAP(-/-)vim(-/-) mouse retina before detachment. The end foot region of these cells may be structurally reinforced by the presence of the intermediate filament cytoskeleton, and our data suggest a critical role for these proteins in M?ller cell reaction to retinal detachment and participation in subretinal gliosis.
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| 31. |
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| 32. |
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| 33. |
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| 34. |
- Walsh, J. M., et al.
(author)
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Discrimination against the Cytosine Analog tC by Escherichia coli DNA Polymerase IV DinB
- 2011
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In: Journal of Molecular Biology. - : Elsevier BV. - 0022-2836 .- 1089-8638. ; 409:2, s. 89-100
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Journal article (peer-reviewed)abstract
- The cytosine analog 1,3-diaza-2-oxophenothiazine (tC) is a fluorescent nucleotide that forms Watson Crick base pairs with dG. The Klenow fragment of DNA polymerase I (an A-family polymerase) can efficiently bypass tC on the template strand and incorporate deoxyribose-triphosphate-tC into the growing primer terminus. Y-family DNA polymerases are known for their ability to accommodate bulky lesions and modified bases and to replicate beyond such nonstandard DNA structures in a process known as translesion synthesis. We probed the ability of the Escherichia coli Y-family DNA polymerase DinB (Pol IV) to copy DNA containing tC and to incorporate tC into a growing DNA strand. DinB selectively adds dGTP across from tC in template DNA but cannot extend beyond the newly formed G:tC base pair. However, we find that DinB incorporates the tC deoxyribonucleotide triphosphate opposite template G and extends from tC. Therefore, DinB displays asymmetry in terms of its ability to discriminate against the modification of the DNA template compared to the incoming nucleotide. In addition, our finding that DinB (a lesion-bypass DNA polymerase) specifically discriminates against tC in the template strand may suggest that DinB discriminates against template modifications in the major groove of DNA.
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| 35. |
- Widestrand, Åsa, 1978, et al.
(author)
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Increased neurogenesis and astrogenesis from neural progenitor cells grafted in the hippocampus of GFAP-/- Vim-/- mice.
- 2007
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In: Stem cells (Dayton, Ohio). - : Oxford University Press (OUP). - 1549-4918 .- 1066-5099. ; 25:10, s. 2619-27
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Journal article (peer-reviewed)abstract
- After neurotrauma, ischemia, or neurodegenerative disease, astrocytes upregulate their expression of the intermediate filament proteins glial fibrillary acidic protein (GFAP), vimentin (Vim), and nestin. This response, reactive gliosis, is attenuated in GFAP(-/-)Vim(-/-) mice, resulting in the promotion of synaptic regeneration after neurotrauma and improved integration of retinal grafts. Here we assessed whether GFAP(-/-)Vim(-/-) astrocytes affect the differentiation of neural progenitor cells. In coculture with GFAP(-/-)Vim(-/-) astrocytes, neural progenitor cells increased neurogenesis by 65% and astrogenesis by 124%. At 35 days after transplantation of neural progenitor cells into the hippocampus, adult GFAP(-/-)Vim(-/-) mice had more transplant-derived neurons and astrocytes than wild-type controls, as well as increased branching of neurite-like processes on transplanted cells. Wnt3 immunoreactivity was readily detected in hippocampal astrocytes in wild-type but not in GFAP(-/-)Vim(-/-) mice. These findings suggest that GFAP(-/-)Vim(-/-) astrocytes allow more neural progenitor cell-derived neurons and astrocytes to survive weeks after transplantation. Thus, reactive gliosis may adversely affect the integration of transplanted neural progenitor cells in the brain. Disclosure of potential conflicts of interest is found at the end of this article.
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| 36. |
- Wilhelmsson, Dennis, 1980, et al.
(author)
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X-ray tomography data of compression tested unidirectional fibre composites with different off-axis angles
- 2019
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In: Data in Brief. - : Elsevier BV. - 2352-3409. ; 25
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Journal article (peer-reviewed)abstract
- This data article contains lab-based micro-computed tomography (μCT) data of unidirectional (UD) non-crimp fabric (NCF) carbon fibre reinforced composite specimens that have been deformed by compression. The specimens contain UD fibres with off-axis angles of 0°, 5°, 10°, 15° and 20° and the compression testing induces kink-band formation. This data formed the basis for the analysis of the influence of in-plane shear on kink-plane orientation as reported in Wilhelmsson et al. (Wilhelmsson et al., 2019).
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| 37. |
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| 38. |
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| 39. |
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| 40. |
- Wilhelmsson, Ola, et al.
(author)
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Structural, electrical and mechanical characterization of magnetron-sputtered
- 2008
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In: Acta Materialia. - : Elsevier BV. - 1359-6454 .- 1873-2453. ; 56:11, s. 2563-2569
-
Journal article (peer-reviewed)abstract
- V2GeC MAX-phase thin films were deposited by DC magnetron sputter epitaxy in the temperature range 450–850 °C. The MAX-phase nucleates directly on (0 0 0 l)-oriented sapphire-wafer substrates without the need for a seed layer. The films contain, however, a small fraction of binary vanadium carbide (VCx) inclusions. X-ray diffraction analysis furthermore shows that these inclusions partly consist of the ordered superstructure V8C7. The amount of Ge in the films decreases at higher temperatures, which can be attributed to Ge evaporation. At temperatures below 450 °C the films consist of polycrystalline Ge and an X-ray amorphous carbide phase attributed to VCx or V2C. No MAX-phase was observed in this temperature region. The electrical and mechanical properties of the films were characterized.
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| 41. |
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| 42. |
- Wilhelmsson, Ulrika, 1970, et al.
(author)
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Astrocytes negatively regulate neurogenesis through the Jagged1-mediated notch pathway.
- 2012
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In: Stem cells (Dayton, Ohio). - : Oxford University Press (OUP). - 1549-4918 .- 1066-5099. ; 30:10, s. 2320-9
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Journal article (peer-reviewed)abstract
- Adult neurogenesis is regulated by a number of cellular players within the neurogenic niche. Astrocytes participate actively in brain development, regulation of the mature central nervous system (CNS), and brain plasticity. They are important regulators of the local environment in adult neurogenic niches through the secretion of diffusible morphogenic factors, such as Wnts. Astrocytes control the neurogenic niche also through membrane-associated factors, however, the identity of these factors and the mechanisms involved are largely unknown. In this study, we sought to determine the mechanisms underlying our earlier finding of increased neuronal differentiation of neural progenitor cells when cocultured with astrocytes lacking glial fibrillary acidic protein (GFAP) and vimentin (GFAP(-/-) Vim(-/-) ). We used primary astrocyte and neurosphere cocultures to demonstrate that astrocytes inhibit neuronal differentiation through a cell-cell contact. GFAP(-/-) Vim(-/-) astrocytes showed reduced endocytosis of Notch ligand Jagged1, reduced Notch signaling, and increased neuronal differentiation of neurosphere cultures. This effect of GFAP(-/-) Vim(-/-) astrocytes was abrogated in the presence of immobilized Jagged1 in a manner dependent on the activity of γ-secretase. Finally, we used GFAP(-/-) Vim(-/-) mice to show that in the absence of GFAP and vimentin, hippocampal neurogenesis under basal conditions as well as after injury is increased. We conclude that astrocytes negatively regulate neurogenesis through the Notch pathway, and endocytosis of Notch ligand Jagged1 in astrocytes and Notch signaling from astrocytes to neural stem/progenitor cells depends on the intermediate filament proteins GFAP and vimentin.
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| 43. |
- Wilhelmsson, Ulrika, 1970, et al.
(author)
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Nestin Regulates Neurogenesis in Mice Through Notch Signaling From Astrocytes to Neural Stem Cells
- 2019
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In: Cerebral Cortex. - : Oxford University Press (OUP). - 1047-3211 .- 1460-2199. ; 29:10, s. 4050-4066
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Journal article (peer-reviewed)abstract
- The intermediate filament (nanofilament) protein nestin is a marker of neural stem cells, but its role in neurogenesis, including adult neurogenesis, remains unclear. Here, we investigated the role of nestin in neurogenesis in adult nestin-deficient (Nes(-/-)) mice. We found that the proliferation of Nes(-/-) neural stem cells was not altered, but neurogenesis in the hippocampal dentate gyrus of Nes(-/-) mice was increased. Surprisingly, the proneurogenic effect of nestin deficiency was mediated by its function in the astrocyte niche. Through its role in Notch signaling from astrocytes to neural stem cells, nestin negatively regulates neuronal differentiation and survival; however, its expression in neural stem cells is not required for normal neurogenesis. In behavioral studies, nestin deficiency in mice did not affect associative learning but was associated with impaired long-term memory.
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