| 1. |
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| 2. |
- Cho, C. R., et al.
(författare)
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Na0.5K0.5NbO3 thin films for MFIS_FET type non-volatile memory applications
- 2002
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Ingår i: Integrated Ferroelectrics. - 1058-4587 .- 1607-8489. ; 49, s. 21-30
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Tidskriftsartikel (refereegranskat)abstract
- Na0.5K0.5NbO3(NKN) thin films have been prepared on Pt80Ir20, SiO2/Si, and Ta2O5/Si substrates for ferroelectric non-volatile memory applications. Ferroelectric hysteresis loops for Au/NKN/Pt80Ir20 vertical capacitor yielded remnant polarization of 12 muC/cm(2) and coercive field similar to20 kV/cm. Significant flat-band voltage V-FB shifts with buffer layer thickness in Au/NKN/SiO2/Si structures have been attributed to the intermixing between Na and K alkali ions and SiO2 layer. On the other hand, Au/NKN/Ta2O5/Si structure exhibited wide memory window without significant V-FB deviations, low leakage currents, and rather long retention time at zero bias.
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| 3. |
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| 4. |
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| 5. |
- Nilsson, Harriet M., et al.
(författare)
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Nitric oxide modulates intracellular translocation of pigment organelles in Xenopus laevis melanophores
- 2000
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Ingår i: Cell Motility and the Cytoskeleton. - 0886-1544 .- 1097-0169. ; 47:3, s. 209-218
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Tidskriftsartikel (refereegranskat)abstract
- Pigment organelles in Xenopus laevis melanophores are used by the animal to change skin color, and they provide a good model for studying intracellular organelle transport. Movement of organelles and vesicles along the cytoskeleton is essential for many processes, such as axonal transport, endocytosis, and intercompartmental trafficking. Nitric oxide (NO) is a signaling molecule that plays a role in, among other things, relaxation of blood vessels, sperm motility, and polymerization of actin. Our study focused on the effect NO exerts on cytoskeleton-mediated transport, which has previously received little attention. We found that an inhibitor of NO synthesis, N-nitro-L-arginine methyl ester (L-NAME), reduced the melatonin-induced aggregation of the pigment organelles, melanosomes. Preaggregated melanosomes dispersed after treatment with L-NAME but not after exposure to the inactive stereoisomer (D-NAME) or the substrate for NO synthesis (L-arginine). Signal transduction by NO can be mediated through the activation of soluble guanylate cyclase (sGC), which leads to increased production of cGMP and activation of cGMP-dependent kinases (PKG). We found that both the sGC inhibitor 1H-(1,2,4) oxadiazolo(4,3-a)quinoxalin-1-one (ODQ) and the cGMP analogue 8-bromoguanosine 3′:5′-cyclic monophosphate (8-Br-cGMP) reduced melanosome aggregation, whereas the PKG inhibitor KT582 did not. Our results demonstrate that melanosome aggregation depends on synthesis of NO, and NO deprivation causes dispersion. It seems, thus, as if NO and cGMP are essential and can regulate melanosome translocation.
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| 6. |
- Seyedi, M, et al.
(författare)
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The cytokinin 2-isopentenyladenine causes partial reversion to skotomorphogenesis and induces formation of prolamellar bodies and protochlorophyllide(657) in the lip1 mutant of pea
- 2001
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Ingår i: Physiologia Plantarum. - 0031-9317 .- 1399-3054. ; 112:2, s. 261-272
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Tidskriftsartikel (refereegranskat)abstract
- When grown in darkness the photomorphogenic lip1 mutant of pea (Pisum sativum L.) has a slender stem, expanded leaves, prolamellar body (PLB) lacking plastids with the size of chloroplasts and a low level of phytochrome A. The lack of PLBs in a dark-grown material (lip1) created a possibility to further study the regulation of their formation in relation to plant development, Inclusion of a cytokinin, 2-isopentenyladenine (2iP), in a medium supporting growth of the pea seedlings in darkness was found to reduce epicotyl length in the wild type. In lip1 the formation of a slender stem was inhibited and a short epicotyl developed. Furthermore, leaf expansion was inhibited, the plastid size reduced and the formation of PLBs induced. The PLB formation in lip1 was not accompanied by an increase in the amount of protochlorophyllide (Pchlide) or Pchilde oxidoreductase (POR), In the presence of 2iP the level of phytochrome A protein was increased in lip1 and the FOR mRNA levels decreased in both lip1 and wild-type plants. The chloroplast characteristic trans-3-hexadecenoate acyl group of phosphatidylglycerol, present in the plastids of dark-grown lip1, was not influenced by 2iP, Thus, not all photomorphogenic processes reacted similarly in the lip1 mutant, but leaf expansion and plastid differentiation, including PLB formation, seemed to be regulated by the same signal transduction chain, Exogenously applied brassinolide could rescue neither dark- nor light-grown defects of the lip1 mutant. Thus, cytokinins but not brassinolides seem to be involved in the regulation of certain characteristic traits of skotomorphogenesis in pea, including plastid development and PLB formation.
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| 7. |
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| 8. |
- Amirjani, M. R., et al.
(författare)
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Regeneration of protochlorophyllide in green and greening leaves of plants with varying proportions of protochlorophyllide forms in darkness
- 2004
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Ingår i: Physiologia Plantarum. - : Wiley. - 0031-9317 .- 1399-3054. ; 121:3, s. 377-390
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Tidskriftsartikel (refereegranskat)abstract
- During illumination of dark-grown plants protochlorophyllide (Pchlide) is continuously transformed to chlorophyllide (Chlide). Different dark-grown plants, maize (Zea mays cv. Sundance), wheat (Triticum aestivum cv. Kosack), pea (Pisum sativum cv. Kelwedon wonder), the lip1 mutant of pea, and the aurea mutant of tomato (Solanum lycopersicum), have various ratios of spectral Pchlide forms in darkness. When the plants were illuminated and then returned to darkness Pchlide re-accumulated. The proportions of different Pchlide forms within the pool of re-accumulated Pchlide were followed by low temperature fluorescence emission and excitation spectra in green and greening leaves. After 1 h of illumination the spectral characteristics of regenerated Pchlide forms mirrored those of Pchlide in dark-grown plants and were thus species dependent. After a prolonged illumination period (24 h) as well as in fully green leaves energy transfer to chlorophyll (Chl) masked the presence of long-wavelength Pchlide in the fluorescence emission spectra. However, excitation spectra showed Pchlide absorption around 650 nm and its flash-induced disappearance confirmed its nature of phototransformable Pchlide. In fact the excitation spectra showed that the proportions of different Pchlide forms in green leaves highly resembled the proportions of Pchlide forms in dark-grown leaves and were specific for the plant variety. Thus Chl formation in both dark-grown and light-grown leaves can occur in a similar way through the main photoactive long-wavelength form of Pchlide.
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| 9. |
- Buga, Sergei G., et al.
(författare)
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Pressure effect on electrical properties and photoluminescence spectra of solid C60 and C70 fullerenes
- 2001
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Ingår i: Frontiers of High Pressure Research II: Application of High Pressure to Low-Dimensional Novel Electronic Materials. - Dordrecht : Springer/Kluwer. - 9781402001604 ; , s. 483-491
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Konferensbidrag (refereegranskat)abstract
- Electrical resistivity of crystalline and disordered fullerite samples obtained by static high-pressure-high-temperature treatment of C-60 and C-70 at P = 12.5 GPa and T = 820-1500 K was investigated in the temperature range of 2.4-300 K, Room-temperature activation energy of charge carriers was found to be in the range 40-200 meV. T-3/2 and T-4 dependencies of conductivity versus temperature were revealed both in crystalline and disordered structures. Photoluminescence spectra of C-60 samples treated at P = 13 GPa. T = 770-1470 K show 50 nm short-wave length shift of characteristic 750 nm PL band.
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| 10. |
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| 11. |
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| 12. |
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| 13. |
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| 14. |
- Engman, M., et al.
(författare)
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Some design considerations of high density base metal tailings handling systems
- 2004
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Ingår i: Proceedings of the 12th international conference on Transport & sedimentation of solid particles joined with 12th international symposium on Freight pipelines. - Prague : Institute of Hydrodynamics, Academy of Sciences of the Czech Republic. - 8023934651 ; , s. 307-318
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Konferensbidrag (refereegranskat)
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| 15. |
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| 16. |
- Eriksson, Ola, et al.
(författare)
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ORWARE : a simulation tool for waste management
- 2002
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Ingår i: Resources, Conservation and Recycling. - 0921-3449 .- 1879-0658. ; 36:4, s. 287-307
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Tidskriftsartikel (refereegranskat)abstract
- A simulation model, ORWARE (ORganic WAste REsearch) is described. The model is mainly used as a tool for researchers in environmental systems analysis of waste management. It is a computer-based model for calculation of substance flows, environmental impacts, and costs of waste management. The model covers, despite the name, both organic and inorganic fractions in municipal waste. The model consists of a number of separate submodels, which describes a process in a real waste management system. The submodels may be combined to design a complete waste management system. Based on principles from life cycle assessment the model also comprises compensatory processes for conventional production of e.g. electricity, district heating and fertiliser. The compensatory system is included in order to fulfil the functional units, i.e. benefits from the waste management that are kept constant in the evaluation of different scenarios. ORWARE generates data on emissions, which are aggregated into different environmental impact categories, e.g. the greenhouse effect, acidification and eutrophication. Throughout the model all physical flows are described by the same variable vector, consisting of up to 50 substances. The extensive vector facilitates a thorough analysis of the results, but involves some difficulties in acquiring relevant data. Scientists have used ORWARE for 8 years in different case studies for model testing and practical application in the society. The aims have e.g. been to evaluate waste management plans and to optimise energy recovery from waste.
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| 17. |
- Johansson, M, et al.
(författare)
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HfO2 gate dielectrics on strained-Si and strained-SiGe layers
- 2003
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Ingår i: Semiconductor Science and Technology. - : IOP Publishing. - 0268-1242 .- 1361-6641. ; 18:9, s. 820-826
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Tidskriftsartikel (refereegranskat)abstract
- We report on materials and device characterization of polycrystalline HfO2 gate dielectrics grown by atomic layer deposition (ALD) at 600 degreesC on strained-Si and strained-SiGe layers. No change in the diffusion profile of Hf into the Si substrate was observed for temperatures in the range 900-1100 degreesC for 20 min. The strain status in the Si layer remained unaltered after HfO2 deposition and an interface state density of similar to1 x 10(11) cm(-2) eV(-1) was obtained for the thicker HfO2 films. The breakdown fields were in the range 2-5 MV cm(-1), which is high compared to HfO2 films grown at higher temperatures. The leakage current was reduced by more than five orders of magnitude for the thin HFO2 with an EOT of 1.25 nm and ultra-thin cap (2.5-3 nm) layers on Si0.77Ge0.23/Si, though high interface state densities (similar to1 x 10(12) cm(-2) eV(-1)) were observed. The carrier transport through these HfO2 films was found to follow Frenkel-Poole emission over a wide range of applied gate voltages.
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| 18. |
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| 19. |
- Makarova, Tatiana L, et al.
(författare)
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Anisotropic metallic properties of highly-oriented rhombohedral C60 polymer.
- 2001
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Ingår i: Synthetic Metals vol. 121. - Amsterdam : Elsevier B.V.. ; , s. 1099-1100
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Konferensbidrag (refereegranskat)abstract
- The pure rhombohedral phase of C60 polymer displays highly anisotropic electrical properties. Conductivity in the polymerized (001) planes exhibits a metal-insulator transition and shows the features of 2D weak localization. Anisotropy ratio is temperature-dependent and reaches 10_6. Dysonian ESR lineshape is consistent with the metallic nature of the samples.
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| 20. |
- Makarova, Tatiana L, et al.
(författare)
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Conductivity of two-dimensional C60 polymers
- 2000
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Ingår i: Proceedings of the 4th International Workshop on Fullerenes and Atomic Clusters (IWFAC'99), St. Petersburg 1999. - : Overseas Publishers Association N.V.. ; , s. 151-156
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Konferensbidrag (refereegranskat)abstract
- The general trend in the shift of electronic properties as the result of polymerization has been studied with the aid of temperature dependences of conductivity. Samples representing the pure rhombohedral phase exhibit great anisotropy in their electrical properties. The main features of the behaviour of these samples are: (i) in the z-direction the resistivity is of the order of several kOhm cm and decreases with temperature; (ii) in the x-y direction resistivity is less than 1 Ohm cm and shows a minimum at a certain temperature.
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| 21. |
- Makarova, Tatiana L, et al.
(författare)
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Electrical properties of two-dimensional fullerene matrices
- 2001
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Ingår i: Carbon. - : Elsevier B.V.. - 0008-6223 .- 1873-3891. ; 39:14, s. 2203-2209
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Tidskriftsartikel (refereegranskat)abstract
- The electrical properties of two-dimensionally polymerized C60 fullerenes were studied. Fullerene matrices consisting of randomly oriented domains are compared to the highly-oriented rhombohedral phase. The conductivity of the randomly oriented polymers obeys the Arrhenius law and can be described in a multiple trapping model. The oriented phase of polymeric C60 shows a distinct anisotropy in the electrical properties with a metallic-like in-plane conductivity at high temperatures.
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| 22. |
- Nilsson, Harriet M., et al.
(författare)
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L-NAME-induced dispersion of melanosomes in melanophores activates PKC, MEK and ERK1
- 2001
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Ingår i: Pigment Cell Research. - : Wiley. - 0893-5785 .- 1600-0749. ; 14:6, s. 450-455
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Tidskriftsartikel (refereegranskat)abstract
- Melanosome movement represents a good model of cytoskeleton-mediated transport of organelles in eukaryotic cells. We recently observed that inhibiting nitric oxide synthase (NOS) with Nω-nitro-l-arginine methyl ester (l-NAME) induced dispersion in melanophores pre-aggregated with melatonin. Activation of cyclic adenosine 3′,5′-monophosphate (cAMP)-dependent protein kinase (PKA) or calcium-dependent protein kinase (PKC) is known to cause dispersion. Also, PKC and NO have been shown to regulate the mitogen/extracellular signal-regulated kinase (MEK)-ERK pathway. Accordingly, our objective was to further characterize the signaling pathway of l-NAME-induced dispersion. We found that the dispersion was decreased by staurosporine and PD98059, which respectively inhibit PKC and MEK, but not by the PKA inhibitor H89. Furthermore, Western blotting revealed that ERK1 kinase was phosphorylated in l-NAME-dispersed melanophores. l-NAME also caused dispersion in latrunculin-B-treated cells, suggesting that this effect is not due to inhibition of the melatonin signaling pathway. Summarizing, we observed that PKC and MEK inhibitors decreased the l-NAME-induced dispersion, which caused phosphorylation of ERK1. Our results also suggest that NO is a negative regulator of phosphorylations that leads to organelle transport.
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| 23. |
- Palm, A, et al.
(författare)
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Capillary isoelectric focusing of proteins utilizing poly(vinylpyrrolodone)- and plexigla-coated columns
- 2004
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Ingår i: Journal of Separation Science. - : Wiley. - 1615-9314 .- 1615-9306. ; 27:1-2, s. 124-128
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Tidskriftsartikel (refereegranskat)abstract
- Fused-silica capillaries chemically derivatized with silane/poly(vinylpyrrolidone) (PVP) or dynamically modified with plexiglas [poly(methyl methacrylate)] were prepared and evaluated with regard to column stability and separation performance for capillary isoelectric focusing of standard proteins. The PVP coating showed the better stability and was good for at least 100 runs while the plexiglas coating started to deteriorate after about 30 runs. The time spent for the plexiglas coating is about 40 minutes while the PVP coating requires two days. The migration time reproducibility was better with the PVP capillary (RSD 0.7-1.6%, n = 5) compared to the plexiglas-coated column (RSD 1.2-2.9%, n = 5) while peak area and height varied over a similar interval (RSD 2-28.1% area; 0.9-22.7% height, n = 5). The two most consistent proteins in this evaluation, viz. myoglobin A and carbonic anhydrase II, showed linear dynamic ranges between 5-150 and 5-50 mug/mL, and limits of detections at 2 and 1 mug/mL, respectively, employing UV detection at 280 nm.
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| 24. |
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| 25. |
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| 26. |
- Yousif, M. Y. A., 1963, et al.
(författare)
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HfO2 for strained-Si and strained-SiGe MOSFETs
- 2003
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Ingår i: ESSDERC 2003. Proceedings of the 33rd European Solid-State Device Research - ESSDERC '03. - 1930-8876. - 0780379993 ; , s. 255-
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Konferensbidrag (refereegranskat)abstract
- We report on HfO2 gate dielectrics grown by atomic layer deposition (ALD) at 600°C on strained-Si and strained-SiGe layers. The strain status in the Si layer remained unaltered after HfO2 deposition and an interface state density of ~1×1011 cm-2 eV-1 was obtained for the case of thick HfO2 films. The breakdown fields were in the range 2-5 MV/cm, which is high compared to HfO2 films grown at higher temperatures. The leakage current was reduced by more than five orders of magnitude for the case of a thin HfO2 film with an EOT of 1.25 nm and ultra-thin cap (2.5-3 nm) layers on Si0.77Ge0.23/Si. The carrier transport through these HfO2 films was found to follow Frenkel-Poole emission over a wide range of applied gate voltage
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