| 1. |
- Adolfsson, Dan E., 1989-, et al.
(författare)
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Enhanement of amyloid fibril binding by ring expansion of thiazolino fused 2-pyridone peptidomimetics
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Thiazolino fused 2-pyridones undergo thiazoline ring opening by reaction with 2-nitrobenzyl bromide through thi- oether attack, and base promoted fragmentation of the resulting sulfonium ions. Subsequent deprotonation of the benzylic carbon and intramolecular 1,4-addition leads to ring closure, generating dihydrothiazine fused 2-pyridones by net ring expansion of the thiazoline ring. Application of the ring expansion procedure to the pyridine and pyrimidine fused thiazolino 2-pyridones provided compounds with enhanced fibril binding activity.
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| 2. |
- Adolfsson, Dan E., 1989-, et al.
(författare)
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Intramolecular Povarov Reactions for the Synthesis of Chromenopyridine fused 2-Pyridone Polyheterocycles Binding to α-Synuclein and Amyloid-β fibrils
- 2020
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Ingår i: Journal of Organic Chemistry. - : American Chemical Society (ACS). - 0022-3263 .- 1520-6904. ; 85:21, s. 14174-14189
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- A BF3×OEt2 catalyzed intramolecular Povarov reaction was used to synthesize a library of 15 chromenopyridine fused thiazolino-2-pyridone peptidomimetics. The reaction works with a range of O-alkylated salicylaldehydes and amino functionalized thiazolino-2-pyridones, to generate polyheterocycles with diverse substitution. The synthesized compounds were screened for their ability to bind α-synuclein and amyloid β fibrils in vitro. Analogs substituted with a nitro group bind to mature amyloid fibrils, and the activity moreover depends on the positioning of this functional group.
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| 3. |
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| 4. |
- Adolfsson, Göran, 1981, et al.
(författare)
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Direct observation of lateral carrier diffusion in ridge waveguide InGaNAs lasers
- 2009
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Ingår i: IEEE Photonics Technology Letters. - 1041-1135 .- 1941-0174. ; 21:134, s. 134-136
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Tidskriftsartikel (refereegranskat)abstract
- We present results from measurements of the subthreshold lateral spontaneous emission profile in 1.3-mu m wavelength ridge waveguide InGaNAs quantum-well lasers using a scanning near-field optical microscopy technique. The measurements reveal the presence of significant lateral carrier diffusion which has a profound effect on the temperature dependence of the threshold current. This effect is frequently omitted when the characteristic temperature of the threshold current is considered.
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| 5. |
- Adolfsson, Göran, 1981, et al.
(författare)
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Effects of Lateral Diffusion on the Temperature Sensitivity of the Threshold Current for 1.3 um Double Quantum-Well GaInNAs/GaAs Lasers
- 2008
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Ingår i: IEEE Journal of Quantum Electronics. ; 44:7, s. 607-616
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Tidskriftsartikel (refereegranskat)abstract
- We present an experimental and theoretical investigationof the temperature dependence of the threshold current fordouble quantum well GaInNAs–GaAs lasers in the temperaturerange 10 C–110 C. Pulsed measurements of the threshold current have been performed on broad and narrow ridge wave guide(RWG) lasers. The narrow RWG lasers exhibit high characteristic temperatures (T0)of 200 K up to a critical temperature (Tc), above which T0 is reduced by approximately a factor of 2. The T0-values for broad RWG lasers are significantly lower than those for the narrow RWG lasers, with characteristic temperatures on the order of 100 (60) K below (above). Numerical simulations, using a model that accounts for lateral diffusion effects, show good agreement with experimental data and reveal that a weakly temperature dependent lateral diffusion current dominates thethreshold current for narrow RWG lasers.
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| 6. |
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| 7. |
- Adolfsson, Göran, 1981, et al.
(författare)
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Realization of spectrally engineered semiconductor Fabry-Perot lasers with narrow geometrical tolerances
- 2011
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 109:9, s. 093112-
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Tidskriftsartikel (refereegranskat)abstract
- Spectrally engineered semiconductor Fabry-Perot laser resonators are designed to enhance the optical feedback for selected longitudinal modes, which thereby require less gain for lasing. This is achieved by introducing refractive index perturbations along the length of the resonator. However,the physical realization of these resonators is a challenge because of very narrow tolerances; in particular the need for precise positioning of the end facets of the resonator in relation to the perturbations, and the excess propagation loss associated with the perturbations, has been a majorconcern. We report on a method to achieve high-quality end facet mirrors enabling precise positioning relative to the perturbations, the latter which are realized as lateral corrugations of the waveguide. Measurements show that the mirror quality is comparable to that of cleaved mirrorsand that the additional loss introduced by the perturbations adds
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| 8. |
- Adolfsson, Göran, 1981, et al.
(författare)
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Spectral engineering of semiconductor Fabry–Perot laser cavities in the weakly and strongly perturbed regimes
- 2010
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Ingår i: Journal of the Optical Society of America B: Optical Physics. - 1520-8540 .- 0740-3224. ; 27:1, s. 118-127
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Tidskriftsartikel (refereegranskat)abstract
- By inserting index perturbations at certain positions along a semiconductor Fabry–Perot laser cavity thethreshold gain for one or several of the longitudinal cavity modes can be selectively lowered to facilitate, e.g.,single-mode or two-color operation. Previous design methods were limited to a fairly small number of perturbations,leading to only weakly perturbed cavities and thus a limited freedom in tailoring the spectral propertiesof the laser. In our approach we fully account for all multiple-reflection events and use a search spacethat permits any distribution of the locations and lengths of the perturbations. We are therefore able to designcavities with almost arbitrary spectral properties with very low threshold gain values for, e.g., the lasingmodes of a two-color cavity. Constraining the design by reducing the geometrical freedom, which can be used toincrease the smallest feature size to simplify fabrication, we seamlessly approach the weakly perturbed regimewhile maintaining much of the freedom for spectral engineering.
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| 9. |
- Adolfsson, Jörgen
(författare)
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Expression and role of the cytokine tyrosine kinase receptor flt3 in early hematopoiesis
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Mature blood cells are crucial for life, but they have a short lifetime and thus have to be replaced. These mature blood cells are produced by lineage restricted progenitors, which themselves are generated by rare multipotent hematopoietic stem cells (HSCs) in a highly dynamic process called hematopoiesis. In addition to the ability of HSCs to generate all blood cell lineages, they possess the unique property of self-renewal, a process in which a HSC, during a cell division generate at least one daughter cell identical to the parental cell. The maintenance and regulation of HSCs and earliest stages of lineage development are partly controlled by soluble and membrane bound regulators called cytokines. The focus in this thesis has been on the cytokine tyrosine kinase receptor flt3 and its ligand and their role in regulating HSCs and the earliest progenitors in adult murine bone marrow (BM). Earlier studies had implicated a role for flt3 and its ligand in the maintenance of HSCs. When studying mice with targeted deletion of the flt3 ligand (FL), we failed to find any role of flt3 and its ligand in HSC regulation. However, the generation of the common lymphoid progenitor (CLP) and earliest stages of B- and T cell development were severely affected, but not myeloid progenitors or later stages of lymphoid development. Based on flt3 expression, we subfractionated the Lin(-)Sca-1(+)c-kit(+) (LSK) stem cell pool in mouse bone marrow. In contrast to LSKflt3- cells, which sustained multilineage long-term reconstitution, LSKflt3+ cells generated only short-term lymphoid dominated reconstitution when injected into lethally ablated recipients. We also demonstrated the hierarchical relationship at the earliest stages of hematopoiesis, in that LSKflt3- HSCs generate LSKflt3+ cells, which generate the CLP but not the LSKflt3- cells. In the classical model of the hematopoietic hierarchy, the first lineage commitment step of HSCs results in a strict separation into distinct lymphoid and myeloid pathways, generating the recently identified CLP and the common myeloid progenitor (CMP). However, in sharp contrast to LSKflt3-, cells which could generate all blood cell lineages, LSK cells expressing flt3 could not generate megakaryocytes or erythroid cells. Thus, these finding together with the above mentioned relationship between the LSKflt3-, LSKflt3+ and CLP do not support the classical hematopoietic hierarchy model depicting the first lineage commitment generating a strict separation of lymphoid and myeloid pathways. The LSK population contains all LT-HSC activity. However, this population is not homogenous neither in phenotype or function and it has been proposed to contain at least two populations, one with long-term reconstitution (LTR) potential and one with short-term reconstitution potential. Based on the expression of CD34 and flt3 within the adult LSK stem cell pool we were able to subfractionate short-term hematopoietic stem cells (ST-HSC) from the LT-HSCs. In contrast to the LSKCD34-flt3- and LSKCD34+flt3+ cells, the LSKCD34+flt3- is highly enriched for CFU-S activity and capable of rescuing lethally irradiated recipients, fulfilling the criteria of ST-HSCs.
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| 10. |
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