| 1. |
- Abrahamsson, Johanna, 1990, et al.
(författare)
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A Raman spectroscopic approach to investigate the production of biodiesel from soybean oil using 1-alkyl-3-methylimidazolium ionic liquids with intermediate chain length
- 2015
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Ingår i: Applied Energy. - : Elsevier BV. - 1872-9118 .- 0306-2619. ; 154, s. 763-770
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Tidskriftsartikel (refereegranskat)abstract
- We present a Raman spectroscopic study of the conversion of soybean oil into biodiesel by methanol using the lipase B enzyme pseudomonas cepacia as the bio-catalyst and 1-alkyl-3-methylimidazolium ionic liquids (CnC1Im) as co-solvents, where the alkyl chain length is varied from ethyl (n=2) to decyl (n=10). We have limited this study to a low reaction temperature, 40°C, and a low enzyme concentration to investigate the possibility of producing biodiesel with low energy and cost demands. We also demonstrate that Raman spectroscopy is a powerful and straightforward method to estimate the yield of the transesterification reaction, by analysis of the characteristic CO stretching mode found in the range ~1730-1750cm-1. Our results indicate that both reaction yield and reaction rate increase with the chain length, but also that for chains longer than decyl further improvements are marginal. We discuss these results from the viewpoint of local interactions and local structure of the investigated ionic liquids.
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| 2. |
- Andersen, Christen Lykkegaard, et al.
(författare)
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Circulating YKL-40 in patients with essential thrombocythemia and polycythemia vera treated with the novel histone deacetylase inhibitor vorinostat
- 2014
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Ingår i: Leukemia Research. - : Elsevier. - 0145-2126 .- 1873-5835. ; 38:7, s. 816-821
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Tidskriftsartikel (refereegranskat)abstract
- YKL-40 regulates vascular endothelial growth factors and induces tumor proliferation. We investigated YKL-40 before and after treatment with vorinostat in 31 polycythemia vera (PV) and 16 essential thrombocythemia (ET) patients. Baseline PV patient levels were 2 times higher than in healthy controls (P<0.0001) and 1.7 times higher than in ET (P = 0.02). A significant correlation between YKL-40 at baseline and neutrophils, CRP, LDH, JAK2V617F and platelets in PV patients was observed, as well as a significantly greater reduction of YKL-40 levels in PV patients responding to therapy. YKL-40 might be a novel marker of disease burden and progression in myeloproliferative neoplasms.
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| 3. |
- Andréasson, Emil, et al.
(författare)
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The Subcellular Localization of the Receptor for Platelet-Activating Factor in Neutrophils Affects Signaling and Activation Characteristics
- 2013
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Ingår i: Clinical & Developmental Immunology. - : Hindawi Limited. - 1740-2522 .- 1740-2530.
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Tidskriftsartikel (refereegranskat)abstract
- The localization in neutrophils, of the receptor for platelet-activating factor (PAFR), has been determined using subcellular fractionation and a receptor mobilization protocol. We show that the PAFR is expressed primarily in the plasma membrane. Although activation of neutrophils by PAF induces responses typical also of agonists that bind the formyl peptide receptors (FPR), known to be stored in mobilizable organelles, some quantitative as well as qualitative differences were observed when neutrophils were activated through these receptors. PAF is equipotent to fMLF (high affinity agonist for FPR1) to cleave off L-selectin and to induce granule/vesicle secretion but is more potent than fMLF to induce a rise in intracellular Ca2+. Similar to fMLF, PAF induced also a robust release of reactive oxygen species, but with higher EC50 value and was less sensitive to a PI3K inhibitor compared to the fMLF response. Despite the lack of a granule localized storage pool of receptors, the PAF-induced superoxide production could be primed; receptor mobilization was, thus, not required for priming of the PAF response. The desensitized PAFR could not be reactivated, suggesting that distinct signaling pathways are utilized for termination of the responses triggered through FPR1 and PAFR.
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| 4. |
- Andréasson, Niclas, 1976, et al.
(författare)
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An Introduction to Continuous Optimization, 3rd edition
- 2016
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Bok (övrigt vetenskapligt/konstnärligt)abstract
- This is the third edition of a book that was originally published in 2005. The book is used primarily in the teaching of the Chalmers course TMA947 Nonlinear Optimization.
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| 5. |
- Forsman, Huamei, et al.
(författare)
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Galectin 3 Aggravates Joint Inflammation and Destruction in Antigen-Induced Arthritis
- 2011
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Ingår i: ARTHRITIS AND RHEUMATISM. - : John Wiley and Sons, Ltd. - 0004-3591 .- 1529-0131. ; 63:2, s. 445-454
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Tidskriftsartikel (refereegranskat)abstract
- Objective. Galectin 3, an endogenous beta galactoside-binding lectin, plays an important role in the modulation of immune responses. The finding that galectin 3 is present in the inflamed synovium in patients with rheumatoid arthritis suggests that the protein is associated with the pathogenesis of this disease. We undertook this study to investigate the influence of galectin 3 deficiency in a murine model of arthritis. Methods. Wild-type (WT) and galectin 3-deficient (galectin 3(-/-)) mice were subjected to antigen-induced arthritis (AIA) through immunization with methylated bovine serum albumin. The concentration of serum cytokines (interleukin-6 [IL-6] and tumor necrosis factor alpha [TNF alpha]) and antigen-specific antibodies was evaluated using a cytometric bead array platform and enzyme-linked immunosorbent assay (ELISA). Cellular IL-17 responses were examined by flow cytometry, ELISA, and enzyme-linked immunospot assay. Results. The joint inflammation and bone erosion of AIA were markedly suppressed in galectin 3(-/-) mice as compared with WT mice. The reduced arthritis in galectin 3(-/-) mice was accompanied by decreased levels of antigen-specific IgG and proinflammatory cytokines. The frequency of IL-17-producing cells in the spleen was reduced in galectin 3(-/-) mice as compared with WT mice. Exogenously added recombinant galectin 3 could partially restore the reduced arthritis and cytokines in galectin 3(-/-) mice. Conclusion. Our findings show that galectin 3 plays a pathogenic role in the development and progression of AIA and that the disease severity is accompanied by alterations of antigen-specific IgG levels, systemic levels of TNF alpha and IL-6, and frequency of IL-17-producing T cells. To our knowledge, this is the first report of in vivo evidence that galectin 3 plays a crucial role in the development of arthritis.
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| 6. |
- Forsman, Huamei, et al.
(författare)
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Reactivation of Desensitized Formyl Peptide Receptors by Platelet Activating Factor: A Novel Receptor Cross Talk Mechanism Regulating Neutrophil Superoxide Anion Production
- 2013
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Ingår i: Plos One. - : Public Library of Science (PLoS). - 1932-6203. ; 8:3
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Tidskriftsartikel (refereegranskat)abstract
- Neutrophils express different chemoattractant receptors of importance for guiding the cells from the blood stream to sites of inflammation. These receptors communicate with one another, a cross talk manifested as hierarchical, heterologous receptor desensitization. We describe a new receptor cross talk mechanism, by which desensitized formyl peptide receptors (FPRdes) can be reactivated. FPR desensitization is induced through binding of specific FPR agonists and is reached after a short period of active signaling. The mechanism that transfers the receptor to a non-signaling desensitized state is not known, and a signaling pathway has so far not been described, that transfers FPRdes back to an active signaling state. The reactivation signal was generated by PAF stimulation of its receptor (PAFR) and the cross talk was uni-directional. LatrunculinA, an inhibitor of actin polymerization, induced a similar reactivation of FPRdes as PAF while the phosphatase inhibitor CalyculinA inhibited reactivation, suggesting a role for the actin cytoskeleton in receptor desensitization and reactivation. The activated PAFR could, however, reactivate FPRdes also when the cytoskeleton was disrupted prior to activation. The receptor cross talk model presented prophesies that the contact on the inner leaflet of the plasma membrane that blocks signaling between the G-protein and the FPR is not a point of no return; the receptor cross-talk from the PAFRs to the FPRdes initiates an actin-independent signaling pathway that turns desensitized receptors back to a signaling state. This represents a novel mechanism for amplification of neutrophil production of reactive oxygen species.
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| 7. |
- Forsman, Huamei, et al.
(författare)
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Structural Characterization and Inhibitory Profile of Formyl Peptide Receptor 2 Selective Peptides Descending from a PIP2-Binding Domain of Gelsolin.
- 2012
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Ingår i: Journal of immunology (Baltimore, Md. : 1950). - : The American Association of Immunologists. - 1550-6606 .- 0022-1767. ; 189:2, s. 629-637
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Tidskriftsartikel (refereegranskat)abstract
- The neutrophil formyl peptide receptors, FPR1 and FPR2, play critical roles for inflammatory reactions, and receptor-specific antagonists/inhibitors can possibly be used to facilitate the resolution of pathological inflammatory reactions. A 10-aa-long rhodamine-linked and membrane-permeable peptide inhibitor (PBP10) has such a potential. This FPR2 selective inhibitor adopts a phosphatidylinositol 4,5-bisphosphate-binding sequence in the cytoskeletal protein gelsolin. A core peptide, RhB-QRLFQV, is identified that displays inhibitory effects as potent as the full-length molecule. The phosphatidylinositol 4,5-bisphosphate-binding capacity of PBP10 was not in its own sufficient for inhibition. A receptor in which the presumed cytoplasmic signaling C-terminal tail of FPR2 was replaced with that of FPR1 retained the PBP10 sensitivity, suggesting that the tail of FPR2 was not on its own critical for inhibition. This gains support from the fact that the effect of cell-penetrating lipopeptide (a pepducin), suggested to act primarily through the third intracellular loop of FPR2, was significantly inhibited by PBP10. The third intracellular loops of FPR1 and FPR2 differ in only two amino acids, but an FPR2 mutant in which these two amino acids were replaced by those present in FPR1 retained the PBP10 sensitivity. In summary, we conclude that the inhibitory activity on neutrophil function of PBP10 is preserved in the core sequence RhB-QRLFQV and that neither the third intracellular loop of FPR2 nor the cytoplasmic tail of the receptor alone is responsible for the specific inhibition.
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| 8. |
- Forsman, Huamei, et al.
(författare)
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WHAT FORMYL PEPTIDE RECEPTORS, IF ANY, ARE TRIGGERED BY COMPOUND 43 AND LIPOXIN A(4) ?
- 2011
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Ingår i: Scandinavian journal of immunology. - : Wiley. - 1365-3083 .- 0300-9475.
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Tidskriftsartikel (refereegranskat)abstract
- In this study we determined receptor preferences for compound 43, a nitrosylated pyrazolone derivative, and the eicosanoid lipoxin A(4) (LXA(4) ), potent anti-inflammatory mediators in many experimental in vivo models Their effects have been suggested to be mediated through binding to FPR2 (earlier known as FPRL1 or ALXR), one of the two members of the formyl peptide receptor family expressed in neutrophils. Compound 43 activates all neutrophil functions investigated whereas LXA(4) induces a unique inhibiting pathway suggested to involve β-arrestin binding as an early signaling step, but not a transient rise in intracellular Ca(2+) . We show that compound 43 can activate not only FPR2 but also FPR1 the other neutrophil receptor in the FPR family, and FPR1 is actually the preferred receptor in human neutrophils and possibly also in the murine equivalent. LXA(4) analogues from two commercial sources were used, and neither of these induced any translocation of β-arrestin as measured in an enzyme-fragment-complementation assay. The conclusions drawn from these experiments are that neither compound 43 nor LXA(4) work as FPR2 agonists in neutrophils, findings of importance for a proper interpretation of results obtained with these compounds as regulators of inflammation.
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| 9. |
- Friel, Ross, Dr, 1982-, et al.
(författare)
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3D Printed Radar Lenses with Anti-Reflective Structures
- 2019
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Ingår i: Designs. - Basel : MDPI. - 2411-9660. ; 3:2
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Tidskriftsartikel (refereegranskat)abstract
- Background: The purpose of this study was to determine if 3D printed lenses with wavelength specific anti-reflective (AR) surface structures would improve beam intensity and thus radar efficiency for a Printed Circuit Board (PCB)-based 60 GHz radar. This would have potential for improved low-cost radar lenses for the consumer product market. Methods: A hyperbolic lens was designed in 3D Computer Aided Design (CAD) software and was then modified with a wavelength specified AR structure. Electromagnetic computer simulation was performed on both the ‘smooth’ and ‘AR structure’ lenses and compared to actual 60 GHz radar measurements of 3D printed polylactic acid (PLA) lenses. Results: The simulation results showed an increase of 10% in signal intensity of the AR structure lens over the smooth lens. Actual measurement showed an 8% increase in signal of the AR structure lens over the smooth lens. Conclusions: Low cost and readily available Fused Filament Fabrication (FFF) 3D printing has been shown to be capable of printing an AR structure coated hyperbolic lens for millimeter wavelength radar applications. These 3D Printed AR structure lenses are effective in improving radar measurements over non-AR structure lenses. © 2019 by the authors. Licensee MDPI, Basel, Switzerland.
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| 10. |
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| 11. |
- Guarese, Renan, et al.
(författare)
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A proposal for augmented situated visualization towards EMC testing
- 2020
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Ingår i: CEUR Workshop Proceedings. - : CEUR-WS. ; , s. 12-15
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Konferensbidrag (refereegranskat)abstract
- Copyright © 2020 for this paper by its authors.In EMC testing, 3D electromagnetic field data often needs to be visually analysed by an expert in order to detect product defects or unwanted interference between multiple devices. In this sense, the present work proposes the use of data visualization techniques allied to an Augmented Reality user interface to provide information that helps professionals to analyse the same data, however spatially situated where it was first measured. Apart from visualizing it, users may also interact with the data to narrow down their search by switching the attributes being displayed, combining them together, applying filters or changing the formatting in which data is presented. The approaches being proposed in this work will ultimately be tested against each other in comparable 2D and 3D interactive visualizations of the same data in a series of usability assessments with users to validate the solutions. The goal is to ultimately expose whether AR can help users to make more accurate decisions, particularly in EMC related tasks.
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| 12. |
- Guarese, Renan, et al.
(författare)
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Augmented situated visualization methods towards electromagnetic compatibility testing
- 2021
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Ingår i: Computers & graphics. - Oxford : Elsevier. - 0097-8493 .- 1873-7684. ; 94, s. 1-10
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Tidskriftsartikel (refereegranskat)abstract
- In electrical engineering, hardware experts often need to analyze electromagnetic radiation data to detect any external interference or anomaly. The field that studies this sort of assessment is called electromagnetic compatibility (EMC). As a way to support EMC analysis, we propose the use of Augmented Situated Visualization (ASV) to supply professionals with visual and interactive information that helps them to comprehend that data, however situating it where it is most relevant in its spatial context. Users are able to interact with the visualization by changing the attributes being displayed, comparing the overlaps of multiple fields, and extracting data, as a way to refine their search. The solutions being proposed in this work were tested against each other in comparable 2D and 3D interactive visualizations of the same data in a series of data-extraction assessments with users, as a means to validate the approaches. Results exposed a correctness-time trade-off between the interaction methods. The hand-based techniques (Hand Slider and Touch Lens) were the least error-prone, being near to half as error-inducing as the gaze-based method. Touch Lens also performed as the least time-consuming method, taking in average less than half of the average time required by the others. For the visualization methods tested, the 2D ray casts presented a higher usability score and lesser workload index than the 3D topology view, however exposing over two times the error ratio. Ultimately, this work exposes how AR can help users to have better performances in a decision-making context, particularly in EMC related tasks, while also furthering the research in the ASV field. © 2020 Elsevier Ltd
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| 13. |
- Hagström, A. L., et al.
(författare)
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An iterative approach to determine the refractive index of 3D printed 60GHz PLA lenses
- 2018
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Ingår i: Proceedings of the 14th Loughborough Antennas and Propagation Conference (LAPC 2018). - Piscataway, N.J. : IEEE. - 9781785619694
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Konferensbidrag (refereegranskat)abstract
- This paper describes an iterative approach to determine quasi-optical properties of standard 3D printer filament material to, in an inexpensive and fast way, construct focusing lenses for millimetre wave systems. Results from three lenses with different focal lengths are shown and discussed. The real part of the permittivity at 60GHz for polylactic acid (PLA) is in this paper determined to be εr=2.74. © 2018 Institution of Engineering and Technology. All rights reserved.
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| 14. |
- Hallgren, Mats, et al.
(författare)
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Associations of device-measured and self-reported physical activity with alcohol consumption : Secondary analyses of a randomized controlled trial (FitForChange).
- 2024
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Ingår i: Drug And Alcohol Dependence. - : Elsevier. - 0376-8716 .- 1879-0046. ; 259
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Physical activity (PA) is increasingly used as an adjunct treatment for alcohol use disorder (AUD). Previous studies have relied on self-report measures of PA, which are prone to measurement error. In the context of a randomized controlled trial of PA for AUD, we examined: (1) associations between device-measured and self-reported PA, (2) associations between PA measurements and alcohol use, and (3) the feasibility of obtaining device-measured PA data in this population.METHOD: One-hundred and forty individuals with clinician-diagnosed AUD participated in a 12-week intervention comparing usual care (phone counselling) to yoga-based exercise and aerobic exercise. Device-measured PA (Actigraph GT3x), self-reported PA (International Physical Activity Questionnaire) and alcohol consumption (Timeline Follow Back Method) were assessed before and after the trial. Effects of the interventions on PA levels were assessed using linear mixed models.RESULTS: In total, 42% (n=59) of participants returned usable device-measured PA data (mean age= 56±10 years, 73% male). Device-measured and self-reported vigorous-intensity PA were correlated (β= -0.02, 95%CI= -0.03, -0.00). No associations were found for moderate-intensity PA. Compared to usual care, time spent in device-measured light-intensity PA increased in the aerobic exercise group (∆= 357, 95%CI= 709, 5.24). Increases in device-measured light-intensity PA were associated with fewer standard drinks (∆= -0.24, 95%CI= -0.03, -0.44), and fewer heavy drinking days (∆= -0.06, 95%CI=-0.01, -0.10).CONCLUSION: Increases in light-intensity/habitual PA were associated with less alcohol consumption in adults with AUD. Self-reported PA data should be interpreted with caution. Incentives are needed to obtain device-measured PA data in AUD populations.
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| 15. |
- Iqbal, Amjad, et al.
(författare)
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SIW-based frequency-adjustable antenna for IoT-based duplex wireless devices
- 2024
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Ingår i: AEU - International Journal of Electronics and Communications. - München : Elsevier. - 1434-8411 .- 1618-0399. ; 173
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Tidskriftsartikel (refereegranskat)abstract
- This paper proposes a compact and frequency-adjustable/reconfigurable dielectric (DR)-loaded eighth-mode substrate integrated waveguide (EMSIW) antenna for duplex wireless communications. The miniaturization of the resonators is realized using a rectangular slot and high isolation is achieved by keeping a reasonable space between them. The proposed design is simulated using a three-dimensional (3D) full-wave simulator, then analysed with a circuit model and finally validated experimentally. Frequency-reconfigurability in the suggested antenna is achieved by placing DRs with different permittivities in the designated holes that are realized in the open-ended portion of each resonator. Consequently, the lower- and high-resonant bands can be reconfigured from 4.70 to 5.23 GHz and from 5.55 to 6.34 GHz, respectively. It is worth mentioning that both resonant band can be independently reconfigured. Moreover, the inter-resonator coupling is always lower than −23.5 dB in the bands of interest. Furthermore, the peak realized gains are always greater than 4.7 dBi in the lower frequency band and 5.5 dBi in the higher one. The suggested antenna has stable radiation properties in both bands in all frequency ranges. Hence, this design is suitable for compact reconfigurable devices due to its compactness, large frequency ranges, stable radiation patterns, and high isolation. © 2023 Elsevier GmbH
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| 16. |
- Patriksson, Michael, 1964, et al.
(författare)
-
Introduction to Continuous Optimization
- 2013
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Bok (övrigt vetenskapligt/konstnärligt)abstract
- This second edition introduces several areas and items that were not included in the first edition, as well as several corrections. A brief summary of these changes are given next. Chapter 1 includes a discussion on the diet problem, in addition to that on the staff planning problem, in order to very early on introduce linear programming. Figure 1.1 now has the terminating box ``Implementation'', whereas the original one had an infinite loop! Chapter 3 has been enriched by several new results on separating and supporting hyperplanes, and the associated theory of convex cones and their polar sets. Thanks to this study of separating hyperplanes,Theorem 5.17 on the necessity of the Fritz John conditions now has a complete proof. The end of Chapter 5 also includes a summary of the fascinating story of the development of the Karush--Kuhn--Tucker conditions. The sensitivity analysis in linear programming has been expanded with a discussion in Section 10.5.3 on the addition of a variable or a constraint, as well as an introduction to column generation based on the example of the minimum cost multi-commodity network flow problem (Section 10.6). Chapter 11 includes a brief discussion on Gauss--Newton methods for least-squares problems. Chapter 12 has changed its name from ``Optimization over convex sets'' to ``Feasible-direction methods,'' in order to reflect the fact that the scope is now wider---from essentially polyhedral sets to general closed sets (which, however, most often will be assumed to be convex). In particular, we have added new sections on algorithms defined by closed descent maps---an algorithm principle which was devised and analyzed mainly in the 1960s, and which is a quite elegant means to describe iterative methods. We also utilize this principle to contrast established convergent methods (such as the Frank--Wolfe method) and failed attempts (such as the algorithm of Zoutendijk). We have also added a brief discussion on reduced gradient methods, which are relatives to the simplex method; they are---in their original statement---not convergent, but a small adjustment results in a closed descent map and hence a convergent method. Exercises and their solutions are now placed at the end of the book, rather than at the end of each chapter. The first edition from 2005 has been used in teaching of several courses at Chalmers University of Technology and the University of Gothenburg. We wish to thank all the students who have given us remarks on the book. We would also like to thank Dr. Kin Cheong Sou for remarks and corrections on the first edition.
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| 17. |
- Stubelius, Alexandra, 1983, et al.
(författare)
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Role of 2-methoxyestradiol as inhibitor of arthritis and osteoporosis in a model of postmenopausal rheumatoid arthritis
- 2011
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Ingår i: Clinical Immunology. - : Elsevier BV. - 1521-6616. ; 140:1, s. 37-46
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Tidskriftsartikel (refereegranskat)abstract
- In postmenopausal rheumatoid arthritis, both the inflammatory disease and estrogen deficiency contribute to the development of osteoporosis. As hormone replacement therapy is no longer an option, we hypothesized that 2-methoxyestradiol (2me2) could be beneficial, and asked if such therapy was associated with effects on reproductive organs. Mice were ovariectomized and arthritis was induced, whereafter mice were administered 2me2, estradiol, or placebo. Clinical and histological scores of arthritis, together with bone mineral density were evaluated. Uteri weight, reactive oxygen species (ROS) from spleen cells, and characterization of cells from joints and lymph nodes were analyzed. In addition, in vivo activation of estrogen response elements (ERE) by 2me2 was evaluated. Treatment with 2me2 and estradiol decreased the frequency and severity of arthritis and preserved bone. Joint destruction was reduced, neutrophils diminished and ROS production decreased. The uterine weight increased upon long-term 2me2 exposure, however short-term exposure did not activate ERE in vivo.
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| 18. |
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