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- Hsiao, Tiger Yu-Yang, et al.
(författare)
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JWST Reveals a Possible z similar to 11 Galaxy Merger in Triply Lensed MACS0647-JD
- 2023
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Ingår i: Astrophysical Journal Letters. - : American Astronomical Society. - 2041-8205 .- 2041-8213. ; 949:2
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Tidskriftsartikel (refereegranskat)abstract
- MACS0647-JD is a triply lensed z similar to 11 galaxy originally discovered with the Hubble Space Telescope. The three lensed images are magnified by factors of similar to 8, 5, and 2 to AB mag 25.1, 25.6, and 26.6 at 3.5 mu m. The brightest is over a magnitude brighter than other galaxies recently discovered at similar redshifts z > 10 with JWST. Here, we report new JWST imaging that clearly resolves MACS0647-JD as having two components that are either merging galaxies or stellar complexes within a single galaxy. The brighter larger component "A" is intrinsically very blue (ss similar to-2.6 +/- 0.1), likely due to very recent star formation and no dust, and is spatially extended with an effective radius similar to 70 +/- 24 pc. The smaller component "B" (r similar to 20-+ 58 pc) appears redder (ss similar to-2 +/- 0.2), likely because it is older (100-200 Myr) with mild dust extinction (AV similar to 0.1 mag). With an estimated stellar mass ratio of roughly 2:1 and physical projected separation similar to 400 pc, we may be witnessing a galaxy merger 430 million years after the Big Bang. We identify galaxies with similar colors in a high-redshift simulation, finding their star formation histories to be dissimilar, which is also suggested by the spectral energy distribution fitting, suggesting they formed further apart. We also identify a candidate companion galaxy "C" similar to 3 kpc away, likely destined to merge with A and B. Upcoming JWST Near Infrared Spectrograph observations planned for 2023 January will deliver spectroscopic redshifts and more physical properties for these tiny magnified distant galaxies observed in the early universe.
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| 2. |
- Safari, Dodi, et al.
(författare)
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Gold nanoparticles as carriers for a synthetic Streptococcus pneumoniae type 14 conjugate vaccine
- 2012
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Ingår i: Nanomedicine. - : Future Medicine Ltd. - 1743-5889 .- 1748-6963. ; 7:5, s. 651-662
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Tidskriftsartikel (refereegranskat)abstract
- Aims: Coupling of capsular polysaccharides of pathogens to immunogenic protein carriers (conjugate vaccines) improves carbohydrate immune response. Our idea is to explore gold nanoclusters as carriers to prepare fully synthetic carbohydrate vaccines. Materials & methods: Gold glyconanoparticles bearing a synthetic tetrasaccharide epitope related to the Streptococcus pneumoniae type 14 capsular polysaccharide (Pn14PS), the T-helper ovalbumin 323-339 peptide (OVA(323-339)), and D-glucose were prepared by a one-pot method. Their immunogenicity was tested in mice. Cytokine levels after spleen cell stimulation with OVA(323-339) were analyzed using a luminex-multiplex cytokine assay. The capacity of the evoked antibodies to promote the uptake of S. pneumoniae type 14 by leukocytes was assessed. Results & discussion: Glyconanoparticles containing 45% of tetrasaccharide and 5% OVA(323-339) triggered specific anti-Pn14PS IgG antibodies. Cytokine levels confirmed that glyconanoparticles led to T-helper cell activation. The antisaccharide antibodies promoted the phagocytosis of type 14 bacteria by human leukocytes, indicating the functionality of the antibodies. Conclusion: Gold nanoparticles have great potential as carriers for the development of a great diversity of fully synthetic carbohydrate-based vaccines.
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| 3. |
- Safari, Dodi, et al.
(författare)
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Identification of the smallest structure capable of evoking opsonophagocytic antibodies against Streptococcus pneumoniae type 14
- 2008
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Ingår i: Infection and Immunity. - : American Society for Microbiology. - 0019-9567 .- 1098-5522. ; 76:10, s. 4615-4623
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Tidskriftsartikel (refereegranskat)abstract
- Synthetic overlapping oligosaccharide fragments of Streptococcus pneumoniae serotype 14 capsular polysaccharide (Pn14PS), {6)-[beta-D-Galp-(1 -> 4)-] beta-D-GlcpNAc-(1 -> 3)-beta-D-Galp-(1 -> 4)-beta-D-Glcp-(1 -> 3}(n), were conjugated to CRM197 protein and injected into mice to determine the smallest immunogenic structure. The resulting antibodies were then tested for Pn14PS specificity and for their capacity to promote the phagocytosis of S. pneumoniae type 14 bacteria. Earlier studies have reported that the oligosaccharide corresponding to one structural repeating unit of Pn14PS, i.e., Gal-Glc-(Gal-) GlcNAc, induces a specific antibody response to Pn14PS. The broader study described here, which evaluated 16 oligosaccharides, showed that the branched trisaccharide element Glc-(Gal-) GlcNAc is essential in inducing Pn14PS-specific antibodies and that the neighboring galactose unit at the nonreducing end contributes clearly to the immunogenicity of the epitope. Only the oligosaccharide conjugates that produce antibodies recognizing Pn14PS were capable of promoting the phagocytosis of S. pneumoniae type 14. In conclusion, the branched tetrasaccharide Gal-Glc-(Gal-) GlcNAc may be a serious candidate for a synthetic oligosaccharide conjugate vaccine against infections caused by S. pneumoniae type 14.
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