Vitiligo. It is important

Nordlund, James J.; Lerner, Aaron B.

doi:10.1001/archderm.118.1.5

Cited by 270 publications

(276 citation statements)

References 17 publications

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“…The construction of the opacity tables that are needed for the radiation transport relies on monochromatic MARCS opacities (Gustafsson et al 2008), computed in LTE and adopting the solar chemical composition of Grevesse & Sauval (1998), with the exception of the CNO abundances that were set to those of Asplund et al (2005). To speed up the calculations, opacities are grouped into 12 opacity bins according to the ideas of Nordlund (1982), and further elaboration by Ludwig et al (1994) and Vögler et al (2004). In the calculation of the tables, the continuum scattering opacity was added to the true absorption opacity.…”

Section: D Hydrodynamical Co5bold Model Atmospheresmentioning

confidence: 99%

The photospheric solar oxygen project

Steffen

Prakapavičius

Caffau

et al. 2015

A&A

108

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Context. The solar photospheric oxygen abundance is still widely debated. Adopting the solar chemical composition based on the "low" oxygen abundance, as determined with the use of three-dimensional (3D) hydrodynamical model atmospheres, results in a well-known mismatch between theoretical solar models and helioseismic measurements that is so far unresolved. Aims. We carry out an independent redetermination of the solar oxygen abundance by investigating the center-to-limb variation of the O i IR triplet lines at 777 nm in different sets of spectra.Methods. The high-resolution and high signal-to-noise solar center-to-limb spectra are analyzed with the help of detailed synthetic line profiles based on 3D hydrodynamical CO5BOLD model atmospheres and 3D non-LTE line formation calculations with NLTE3D. The idea is to exploit the information contained in the observations at different limb angles to simultaneously derive the oxygen abundance, A(O), and the scaling factor S H that describes the cross-sections for inelastic collisions with neutral hydrogen relative to the classical Drawin formula. Using the same codes and methods, we compare our 3D results with those obtained from the semiempirical Holweger-Müller model atmosphere as well as from different one-dimensional (1D) reference models. Results. With the CO5BOLD 3D solar model, the best fit of the center-to-limb variation of the triplet lines is obtained when the collisions by neutral hydrogen atoms are assumed to be efficient, i.e., when the scaling factor S H is between 1.2 and 1.8, depending on the choice of the observed spectrum and the triplet component used in the analysis. The line profile fits achieved with standard 1D model atmospheres (with fixed microturbulence, independent of disk position μ) are clearly of inferior quality compared to the 3D case, and give the best match to the observations when ignoring collisions with neutral hydrogen (S H = 0). The results derived with the Holweger-Müller model are intermediate between 3D and standard 1D. Conclusions. The analysis of various observations of the triplet lines with different methods yields oxygen abundance values (on a logarithmic scale where A(H) = 12) that fall in the range 8.74 < A(O) < 8.78, and our best estimate of the 3D non-LTE solar oxygen abundance is A(O) = 8.76 ± 0.02. All 1D non-LTE models give much lower oxygen abundances, by up to −0.15 dex. This is mainly a consequence of the assumption of a μ-independent microturbulence. An independent determination of the relevant collisional cross-sections is essential to substantially improve the accuracy of the oxygen abundance derived from the O i IR triplet.

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Section: D Hydrodynamical Co5bold Model Atmospheresmentioning

confidence: 99%

The photospheric solar oxygen project

Steffen

Prakapavičius

Caffau

et al. 2015

A&A

108

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“…Vitiligo is a dermatologic disorder characterized by localized or diffuse depigmented patches on the skin [1,2]. Vitiligo is considered an autoimmune disease due to the following features: the presence of autoantibodies against melanocytes in patients' sera [3][4][5][6][7], the association of vitiligo with other autoimmune conditions [8][9][10], the presence of organ-specific autoantibodies in the patients' sera [11,12], the detection of autoantibodies in firstdegree relatives of subjects with vitiligo [13], and the association of the disease with HLA-DR4 or HLA-DR1 [14][15][16].…”

Section: Introductionmentioning

confidence: 99%

Tyrosinase as an autoantigen in patients with vitiligo

Baharav

Merimski

Shoenfeld

et al. 1996

Clinical and Experimental Immunology

118

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SUMMARYVitiligo is considered an autoimmune disorder due to the generation and presence of autoantibodies directed against melanocyte antigens in the patients' sera. In the present study we point towards a newly defined autoantigen in vitiligo, the enzyme tyrosinase, which participates in the process of melanogenesis. Anti-tyrosinase antibodies were detected in the sera of seven patients with diffuse and 11 patients with localized vitiligo. Employing solid-phase ELISA to mushroom tyrosinase, we found that patients with diffuse vitiligo had significantly higher titres of IgG anti-tyrosinase autoantibodies than patients with localized disease or healthy subjects. These anti-tyrosinase autoantibodies have relatively high functional affinity to tyrosinase and can be recovered from vitiligo patients' sera by affinity purification. The anti-tyrosinase antibodies do not cross-react with other enzymes recognized as autoantigens in different autoimmune disorders and the autoantibodies do not block the enzymatic activity of tyrosinase, indicating that they are not reacting with the catalytic site of the enzyme. These data point to tyrosinase as an autoantigen in vitiligo and suggest that anti-tyrosinase titres can serve as a marker for disease activity.

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“…Whether one uses ray-tracing or flux-limited-diffusion it is often important to include several frequency points (or frequency bins)-representing for example heating in one frequency domain and cooling in another (Nordlund 1982). With ray-tracing, there is enough capacity to employ several frequencies (or frequency bins), while still being able to afford a reasonable space-angle resolution.…”

Section: å Nordlundmentioning

confidence: 99%

Ray Casting and Flux Limited Diffusion

Nordlund¹

2010

Proc. IAU

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Abstract.Solving radiative transfer problems with ray casting methods is compared with the commonly used 'Flux Limited Diffusion' approximation. Whereas ray casting produces solutions that converge to the exact one as the number of rays is increased, flux-limited-diffusion is fundamentally a 'look-alike' method, which produces solutions that are reminiscent of the correct solution but which cannot be made to converge to it.

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Vitiligo. It is important

Cited by 270 publications

References 17 publications

The photospheric solar oxygen project

The photospheric solar oxygen project

Tyrosinase as an autoantigen in patients with vitiligo

Ray Casting and Flux Limited Diffusion

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