| 1. |
|
|
| 2. |
- Balkenius, Christian, et al.
(författare)
-
First steps towards a computational theory of autism
- 2004
-
Ingår i: Proceedings of the fourth international workshop on epigenetic robotics (Lund University Cognitive Studies). - 9197474134 ; 117, s. 27-34
-
Konferensbidrag (refereegranskat)abstract
- A computational model with three interacting components for context sensitive re-inforcement learning, context processing and automation can autonomously learn a focus attention and a shift attention task. The performance of the model is similar to that of normal children, and when a single parameter is changed, the performance on the two tasks approaches that of autistic children.
|
|
| 3. |
- Elmegreen, B.G., et al.
(författare)
-
Hubble Space Telescope Observations of the Interacting Galaxies NGC 2207 and IC 2163
- 2000
-
Ingår i: Astronomical Journal. - : American Astronomical Society. - 1538-3881 .- 0004-6256. ; 120:2, s. 630-644
-
Tidskriftsartikel (refereegranskat)abstract
- Hubble Space Telescope (HST) images of the galaxies NGC 2207 and IC 2163 show star formation and dust structures in a system that has experienced a recent grazing encounter. Tidal forces from NGC 2207 compressed and elongated the disk of IC 2163, forming an oval ridge of star formation along a caustic where the perturbed gas rebounded after its inward excursion. Gas flowing away from this ridge has a peculiar structure characterized by thin parallel dust filaments transverse to the direction of motion. The filaments become thicker and longer as the gas approaches the tidal arm. Star formation that occurs in the filaments consistently lags behind, as if the exponential disk pressure gradient pushes outward on the gas but not on the young stars. Numerical models suggest that the filaments come from flocculent spiral arms that were present before the interaction. The arms stretch out into parallel filaments as the tidal tail forms. A dust lane at the outer edge of the tidal tail is a shock front where the flow abruptly changes direction. Gas at small-to-intermediate radii along this edge flows back toward the galaxy, while elsewhere in the tidal arm, the gas flows outward.A spiral arm of NGC 2207 that is backlit by IC 2163 is seen with HST to contain several parallel, knotty filaments spanning the full width of the arm. These filaments are probably shock fronts in a density wave. The parallel structure suggests that the shocks occur in several places throughout the arm, or that the interarm gas is composed of spiral-like wisps that merge together in the arms. Blue clusters of star formation inside the clumps of these dust lanes show density-wave triggering in unprecedented detail. The star formation process seems to be one of local gravitational collapse, rather than cloud collisions. Spiral arms inside the oval of IC 2163 have a familiar geometry reminiscent of a bar, although there is no obvious stellar bar. The shape and orientation of these arms suggest they could be the result of inner Lindblad resonance–related orbits in the cos 2θ tidal potential that formed the oval. Their presence suggests that tidal forces alone may initiate a temporary nuclear gas flow and eventual starburst without first forming a stellar bar. Several emission structures resembling jets or conical flows that are 100–1000 pc long appear in these galaxies. In the western arm of NGC 2207, there is a dense dark cloud with a conical shape 400 pc long and a bright compact cluster at the tip, and there is a conical emission nebula of the same length that points away from the cluster in the other direction. This region also coincides with a nonthermal radio continuum source that is ~1000 times the luminosity of Cas A at λ = 20 cm. Surrounding clusters in arclike patterns may have been triggered by enormous explosions.
|
|
| 4. |
- Figgemeier, Egbert, et al.
(författare)
-
Modification of electron transfer properties in photoelectrochemical solar cells by substituting {Ru(terpy)(2)}(2+) dyes with thiophene
- 2004
-
Ingår i: Inorganic Chemistry Communications. - : Elsevier BV. - 1387-7003 .- 1879-0259. ; 7:1, s. 117-121
-
Tidskriftsartikel (refereegranskat)abstract
- A comparison of the properties of the 2-thienyl-substituted carboxyphenyl {RuII(terpy)2} dyes with their non-substituted analogues has enabled us to gain insight into the electronic properties that are prerequisite for efficient electron injection into the TiO2 conduction band in photoelectrochemical solar cells. Introducing the thienyl group has a profound effect upon the efficiency of photoinduced electron injection. This effect can be explained by a significant shift in the LUMO position from the terpy ligand anchored on the TiO2 surface towards the 2-thienyl substituted ligand, which is shown by means of electrochemistry and semiempirical calculations.
|
|
| 5. |
- Fisher, D. A., et al.
(författare)
-
The effects of flowline length evolution on chemistry - δ18O profiles from Penny Ice Cap, Baffin Island, Canada
- 2002
-
Ingår i: Annals of Glaciology. - : International Glaciological Society. - 0260-3055 .- 1727-5644. ; 35:1, s. 150-156
-
Tidskriftsartikel (refereegranskat)abstract
- The isotopic and chemical signatures for ice-age and Holocene ice from Summit, Greenland, and Penny Ice Cap, Baffin Island, Canada, are compared. The usual pattern of low δ180, high Ca2+ and high Cl- is presented in the Summit records, but Penny Ice Cap has lower than present Cl- in its ice-age ice. A simple extension of the Hansson model (Hansson, 1994) is developed and used to simulate these signatures. The low ice age Cl- from Penny Ice Cap is explained by having the ice-age ice originating many thousands of km inland near the centre of the Laurentide ice sheet and much further from the marine sources. Summit's flowlines all start close to the present site. The Penny Ice Cap early-Holocene δ180's had to be corrected to offset the Laurentide meltwater distortion.The analysis suggests that presently the Summit and Penny Ice Cap marine impurity ori ginates about 500 km away, and that presently Penny Ice Cap receives a significant amountoflocal continental impurity.
|
|
| 6. |
- Hillier, Ladeana W, et al.
(författare)
-
Sequence and comparative analysis of the chicken genome provide unique perspectives on vertebrate evolution
- 2004
-
Ingår i: Nature. - 0028-0836 .- 1476-4687. ; 432:7018, s. 695-716
-
Tidskriftsartikel (refereegranskat)abstract
- We present here a draft genome sequence of the red jungle fowl, Gallus gallus. Because the chicken is a modern descendant of the dinosaurs and the first non-mammalian amniote to have its genome sequenced, the draft sequence of its genome--composed of approximately one billion base pairs of sequence and an estimated 20,000-23,000 genes--provides a new perspective on vertebrate genome evolution, while also improving the annotation of mammalian genomes. For example, the evolutionary distance between chicken and human provides high specificity in detecting functional elements, both non-coding and coding. Notably, many conserved non-coding sequences are far from genes and cannot be assigned to defined functional classes. In coding regions the evolutionary dynamics of protein domains and orthologous groups illustrate processes that distinguish the lineages leading to birds and mammals. The distinctive properties of avian microchromosomes, together with the inferred patterns of conserved synteny, provide additional insights into vertebrate chromosome architecture.
|
|
| 7. |
- Karlsson, Camilla A.C., et al.
(författare)
-
Non-invasive monitoring of protein adsorption and removal in a turbulent flow cell
- 2001
-
Ingår i: Colloids and Surfaces B: Biointerfaces. - 0927-7765. ; 20:1, s. 9-25
-
Tidskriftsartikel (refereegranskat)abstract
- A flow cell was designed for continuous non-invasive measurements of macromolecular adsorption and removal under well-defined flow conditions. The adsorption of the protein β-lactoglobulin to stainless steel surfaces and its subsequent detergent-induced removal were followed in the flow cell using in situ ellipsometry under both laminar and turbulent conditions. Factors varied include the cleaning agent type and concentration, the flow rate and the protein concentration. In addition, the experiments studying different cleaning agents were repeated in a stirred cuvette system employed in previous work. The ellipsometer as well as the experimental set-ups are described, with particular emphasis on the flow cell design. Evaluation of the results is done by comparing the amounts of protein adsorbed from solution, the initial adsorption rates, the amounts removed in water or detergent and the residual amounts after cleaning. The results are discussed in terms of β-lactoglobulin unfolding, preferential adsorption, different states of adsorbed molecules, additional physicochemical aspects and hydrodynamic characteristics. (C) 2001 Elsevier Science B.V.
|
|
| 8. |
- Larsson, Lena C, et al.
(författare)
-
Induction of operational tolerance to discordant dopaminergic porcine xenografts.
- 2003
-
Ingår i: Transplantation. - 1534-6080 .- 0041-1337. ; 75:9, s. 1448-1454
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Porcine embryonic neural tissue transplanted intracerebrally could potentially relieve the symptoms of Parkinson's disease if the immune response toward the graft could be overcome. However, conventional immunosuppressive treatments have proven inefficient in preventing rejection. An alternative is blocking the costimulatory signals for lymphocyte activation. Treatment with cytotoxic T-lymphocyte antigen 4 immunoglobulin (CTLA4Ig) and anti-CD40L has been successful in preventing rejection of xenografts in some experimental studies, but not all. Lymphocyte function antigen (LFA)-1 is an important costimulatory molecule for CD8+ T cells, and we hypothesize that blockade with anti-LFA-1 may enhance the efficacy of CTLA4Ig and anti-CD40L therapy. METHODS: C57BL/6 mice received intracerebral transplants of ventral mesencephalic tissue from embryonic porcine donors. CTLA4Ig, anti-CD40L, and anti-LFA-1 were administered every other day on days 0 to 8, and the transplants were studied after 4 to 6 weeks. Grafts were histologically analyzed for size, survival of dopaminergic nerve cells, and immune responses. Recipients were challenged with cultured glia cells of donor origin or an allogeneic skin graft to evaluate tolerance induction. RESULTS: Mice treated with all three substances had large grafts containing high amounts of dopamine cells but a low degree of immune response. Grafts in recipients challenged with glial cells showed an increased immunologic activity but were not rejected. Triple-treated mice showed a normal rejection process of the allogeneic skin grafts. CONCLUSION: After a short course of costimulation blocking therapy, discordant neural xenografts demonstrate long-term survival, withstand immunologic challenge, yet maintain host-versus-graft reactivity. Anti-LFA-1 complements CTLA4Ig and anti-CD40L in the induction of operational tolerance to these xenografts.
|
|
| 9. |
- Andersson, Christian X, 1973, et al.
(författare)
-
CD43 has a functional NLS, interacts with beta-catenin, and affects gene expression
- 2004
-
Ingår i: Biochem. Biophys. Res. Commun.. - : Elsevier BV. ; 316:1, s. 12-17
-
Tidskriftsartikel (refereegranskat)abstract
- CD43 is a transmembrane molecule with a highly O-glycosylated extracellular domain of mucin type. It is a normal constituent of leukocytes and found in colon adenoma, but not in normal colon epithelia. Here it is shown that the cytoplasmic tail of CD43 contains a functional bipartite nuclear localization signal directing it to the nucleus. The intracellular domain of CD43 interacts with beta-catenin and causes an upregulation of the beta-catenin target genes c-MYC and CyclinD1. The present results suggest that CD43 can be involved in nuclear signaling and via beta-catenin interaction be involved in cell proliferation.
|
|
| 10. |
- Bergh, Christina, 1953, et al.
(författare)
-
Chromosomal abnormality rate in human pre-embryos derived from in vitro fertilization cycles cultured in the presence of Follicular-Fluid Meiosis Activating Sterol (FF-MAS)
- 2004
-
Ingår i: Hum Reprod. ; 19:9, s. 2109-17
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The objective of the study was to investigate the effect of Follicular-Fluid Meiosis Activating Sterol (FF-MAS) when added to the culture media on the incidence of chromosomal abnormalities and pre-embryo development in human pre-embryos. METHODS: 243 women undergoing IVF/ICSI treatment donated 353 oocytes in a multicentre, prospective, randomized, double blind, four-arm, controlled trial performed at Danish and Swedish public and private IVF centers. Metaphase II oocytes were randomly assigned to: FF-MAS 5 microM, FF-MAS 20 microM, ethanol 0.2% (vehicle control) or water for injection (inert control). The exposure regimen of FF-MAS to the human oocytes was 4 h prior to fertilization by ICSI and 20 h exposure post ICSI. The primary endpoint was the incidence of numerical chromosomal abnormalities. Secondary endpoints were cleavage rate and pre-embryo quality. RESULT: On the pre-embryo level, no significant differences in chromosomal abnormality rate were observed among the four groups. However, the percentage of uniformly normal pre-embryos was significantly lower in the pooled FF-MAS group (5 microM: 12% and 20 microM: 17%) than in the pooled control group (inert control 32% and vehicle control 42%). A high level of mosaicism (41-60%) was found in all groups. At the blastomere level, the percentage of blastomeres categorized as normal was significantly lower in the FF-MAS 5 microM group (41%) and the FF-MAS 20 microM (29%) group versus the inert (52%) and the vehicle (61%) groups. Significantly reduced cleavage and good quality pre-embryo rates were found in both FF-MAS groups. CONCLUSION: FF-MAS increased the rate of aneuploidy and had detrimental effects on cleavage and pre-embryo development, when exposed both before and after fertilization.
|
|
