386 research outputs found

    Antigen processing by epidermal langerhans cells correlates with the level of biosynthesis of major histocompatibility complex class II molecules and expression of invariant chain

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    Two prior studies with a small number of T cell lines have shown that the presentation of native protein antigens by epidermal Langerhans cells (LC) is regulated. When freshly isolated, LC are efficient antigen-presenting cells (APC), but after a period of culture LC are inefficient or even inactive. The deficit in culture seems to be a selective loss in antigen processing, since cultured LC are otherwise rich in major histocompatibility complex (MHC) class II products and are active APC for alloantigens and mitogens, which do not require processing. We have extended the analysis by studying presentation to bulk populations of primed lymph node and a TT hybrid. Only freshly isolated LC can be pulsed with the protein antigens myoglobin and conalbumin, but once pulsed, antigen is retained in an immunogenic form for at least 2 d. The acquisition of antigen, presumably as MHC-peptide complexes, is inhibited if the fresh LC are exposed to foreign protein in the presence ofchloroquine or cycloheximide. The latter, in contrast, improves the efficacy ofantigen pulsing in anti-Ig-stimulated B blasts. In additional studies of mechanism, we noted that both fresh and cultured LC endocytose similar amounts of an antigen, rhodamineovalbumin, into perinuclear granules. However, freshly isolated LC synthesize high levels of class II MHC molecules and express higher amounts of the class II-associated invariant chain. Fresh LC are at least 5-10 times more active than many other cell types in the level of biosynthesis ofMHC class II products. These findings provide a physiologic model in which newly synthesized MHC class II molecules appear to be the principal vehicle for effective antigen processing by APC of the dendritic cell lineage. Another APC, the B lymphoblast, does not appear to require newly synthesized MHC class II molecules for presentation

    Antigen processing by epidermal Langerhans cells correlates with the level of biosynthesis of MHC class II molecules and expression of invariant chain

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    Puré, E., Inaba, K., Crowley, M.T., Tardelli, L., Witmer-Pack, M.D., Ruberti, G., Fathman, G., and Steinman, R.M. Antigen processing by epidermal Langerhans cells correlates with the level of biosynthesis of MHC class II molecules and expression of invariant chain. J. Exp. Med. 172: 1459-1469, 1990https://digitalcommons.rockefeller.edu/historical-scientific-reports/1028/thumbnail.jp

    Dendritic cells are the principal cells in mouse spleen bearing immunogenic fragments of foreign proteins

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    We monitored the APC function of cells taken from the spleen and peritoneal cavity of mice that had been given protein antigens via the intravenous or intraperitoneal routes. Using the mAb 33D1 and N418 to negatively and positively select dendritic cells, we obtained evidence that dendritic cells are the main cell type in spleen that carries the protein in a form that is immunogenic for antigen-specific T cells. In vivo pulsed macrophages were not immunogenic and did not appear capable of transferring peptide fragments to dendritic cells

    Dendritic cells are the principal cell in mouse spleen bearing immunogenic fragments of foreign proteins

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    Crowley, M.T., Inaba, K., and Steinman, R.M. Dendritic cells are the principal cell in mouse spleen bearing immunogenic fragments of foreign proteins. J. Exp. Med. 172: 383-386, 1990https://digitalcommons.rockefeller.edu/historical-scientific-reports/1026/thumbnail.jp

    Electrodialysis for concentrating cobalt, chromium, manganese, and magnesium from a synthetic solution based on a nickel laterite processing route

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    [EN] Due to environmental and human health concerns, the need for cleaner techniques able to extract and recover metals from mining process solutions has been increasing. In this work, the use of electrodialysis for recovering cobalt, magnesium, manganese, and chromium ions from an acid multicomponent solution generated in the nickel laterite processing was evaluated. Values of percent extraction above 98% were obtained for Co2+, Mn2+, and Mg(2+ )ions. For Cr3+, the greatest percent extraction obtained was 83%. The results of percent concentration of the species showed the same trend: for Cr3+ ions, it was significantly lower than the others. Such difference in the transport of the metals through the membranes may have occurred due to the lower molar concentration, lower diffusion coefficient, and greater Stokes radius of chromium ions. Thus, the transfer of Cr3+ was hindered by the presence of other cationic species. This was also evidenced by the results of current efficiency and energy consumption associated with each species in solution. Lastly, the results of solution pH throughout the experiments and the final condition of the membranes, which were analyzed by SEM/EDS, indicated that the water dissociation phenomenon occurred at their surfaces.The authors gratefully acknowledge the financial support given by funding agencies CNPq (Process 141346/2016-7; 171241/2017-7; 160320/2019-4) and FAPESP (Process 2012/51871-9) . This study was financed in part by the Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior-Brasil (CAPES) -Finance Code 001 (Processes 88881.190502/2018-01 and 88887.362657/2019-00) .Feijoo, GC.; Santana-Barros, K.; Scarazzato, T.; Espinosa, D. (2021). Electrodialysis for concentrating cobalt, chromium, manganese, and magnesium from a synthetic solution based on a nickel laterite processing route. Separation and Purification Technology. 275. https://doi.org/10.1016/j.seppur.2021.11919227

    Gravity and Large-Scale Non-local Bias

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    The relationship between galaxy and matter overdensities, bias, is most often assumed to be local. This is however unstable under time evolution, we provide proofs under several sets of assumptions. In the simplest model galaxies are created locally and linearly biased at a single time, and subsequently move with the matter (no velocity bias) conserving their comoving number density (no merging). We show that, after this formation time, the bias becomes unavoidably non-local and non-linear at large scales. We identify the non-local gravitationally induced fields in which the galaxy overdensity can be expanded, showing that they can be constructed out of the invariants of the deformation tensor (Galileons). In addition, we show that this result persists if we include an arbitrary evolution of the comoving number density of tracers. We then include velocity bias, and show that new contributions appear, a dipole field being the signature at second order. We test these predictions by studying the dependence of halo overdensities in cells of fixed matter density: measurements in simulations show that departures from the mean bias relation are strongly correlated with the non-local gravitationally induced fields identified by our formalism. The effects on non-local bias seen in the simulations are most important for the most biased halos, as expected from our predictions. The non-locality seen in the simulations is not fully captured by assuming local bias in Lagrangian space. Accounting for these effects when modeling galaxy bias is essential for correctly describing the dependence on triangle shape of the galaxy bispectrum, and hence constraining cosmological parameters and primordial non-Gaussianity. We show that using our formalism we remove an important systematic in the determination of bias parameters from the galaxy bispectrum, particularly for luminous galaxies. (abridged)Comment: 26 pages, 9 figures. v2: improved appendix

    Two New Gravitationally Lensed Double Quasars from the Sloan Digital Sky Survey

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    We report the discoveries of the two-image gravitationally lensed quasars, SDSS J0746+4403 and SDSS J1406+6126, selected from the Sloan Digital Sky Survey (SDSS). SDSS J0746+4403, which will be included in our lens sample for statistics and cosmology, has a source redshift of z_s=2.00, an estimated lens redshift of z_l~0.3, and an image separation of 1.08". SDSS J1406+6126 has a source redshift of z_s=2.13, a spectroscopically measured lens redshift of z_l=0.27, and an image separation of 1.98". We find that the two quasar images of SDSS J1406+6126 have different intervening MgII absorption strengths, which are suggestive of large variations of absorbers on kpc scales. The positions and fluxes of both the lensed quasar systems are easily reproduced by simple mass models with reasonable parameter values. These objects bring to 18 the number of lensed quasars that have been discovered from the SDSS data.Comment: 25 pages, 6 figures, The Astronomical Journal accepte

    Characterization of the distribution of the Lly\alpha emitters in the 53W002 field at z = 2.4

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    We present the results of our wide-field narrow band imaging of the field around the radio galaxy 53W002 at z = 2.390 with Subaru/Suprime-Cam. A custom made filter NB413 centered at 4140 \AA\ with the width of 83 \AA\ is used to observe the 31' x 24' area around the radio galaxy. We detected 204 Ly\alpha emitters (LAEs) at z = 2.4 with a rest frame equivalent width larger than 25 \AA\ to the depth of 26 AB mag (in NB413). The entire LAE population in the 53W002 field has an average number density and distributions of equivalent width and size that are similar to those of other fields at z ~ 2. We identify a significant high density region (53W002F-HDR) that spreads over ~ 5' x 4' near 53W002 where the LAE number density is nearly four times as large as the average of the entire field. Using the probability distribution function of density fluctuation, we evaluate the rareness probability of the 53W002F-HDR to be 0.9^{+2.4}_{-0.62}%, which corresponds to a moderately rich structure. No notable environmental dependency at the comoving scale of 10 Mpc is found for the distributions of the Ly\alpha equivalent width and luminosity in the field. We also detected 4 Ly\alpha blobs (LABs), one of which is newly discovered. They are all found to be located in the rims of high density regions. The biased location and unique morphologies in Ly\alpha suggest that galaxy interaction play a key role in their formation.Comment: 26 pages, 12 figure

    Discovery of a Gravitationally Lensed Quasar from the Sloan Digital Sky Survey: SDSS J133222.62+034739.9

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    We report the discovery of the two-image gravitationally lensed quasar SDSS J133222.62+034739.9 (SDSS J1332+0347) with an image separation of Delta_theta=1.14". This system consists of a source quasar at z_s=1.445 and a lens galaxy at z_l=0.191. The agreement of the luminosity, ellipticity and position angle of the lens galaxy with those expected from lens model confirms the lensing hypothesis.Comment: 16 pages, 4 figures, the Astronomical Journal accepte

    Measuring our universe from galaxy redshift surveys

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    Galaxy redshift surveys have achieved significant progress over the last couple of decades. Those surveys tell us in the most straightforward way what our local universe looks like. While the galaxy distribution traces the bright side of the universe, detailed quantitative analyses of the data have even revealed the dark side of the universe dominated by non-baryonic dark matter as well as more mysterious dark energy (or Einstein's cosmological constant). We describe several methodologies of using galaxy redshift surveys as cosmological probes, and then summarize the recent results from the existing surveys. Finally we present our views on the future of redshift surveys in the era of Precision Cosmology.Comment: 82 pages, 31 figures, invited review article published in Living Reviews in Relativity, http://www.livingreviews.org/lrr-2004-
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