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12. What Does the Archaeomagnetic Record of Fired Ceramics Reflect?

Author

Pilipenko, O. V., Markov, G. P., Salnaya, N. V., Minaev, P. A., and Aphinogenova, N. A.

Subjects
*GEOMAGNETISM, *THERMOREMANENT magnetization, *FIRING (Ceramics), *CERAMICS, *GRAIN, *SUPERPARAMAGNETIC materials, *HEMATITE, *ROCK deformation
Abstract

Abstract—A complex of archaeomagnetic and rock magnetic studies is conducted to compare the archaeomagnetic intensity determined by the Thellier–Coe and Wilson methods with the known "true" value of the geomagnetic field during the firing of the ceramic samples manufactured on February 21, 2017 in the town of Myshkin (Yaroslavl oblast, Russia). The results obtained show two different values of archaeomagnetic intensity corresponding to two temperature intervals. The archaeomagnetic intensity estimated from the low-temperature interval (~150–350°C) are approximately 13 μT lower than the true value, while the values obtained in the interval of ~350–600°C are fairly close to the "true" ones. The cause of the phenomenon is likely due to the presence of small magnetic grains in the ceramic under study, which are close in size to superparamagnetic ones and can resume their growth upon heating and reaching a particle size in a single-domain state. The results of rock magnetic studies suggest that thermoremanent magnetization in the studied ceramics is carried by grains of oxidized magnetite, hematite, and possibly ε-Fe2O3. [ABSTRACT FROM AUTHOR]

Published
2024
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23. Ocular Syphilis: A Case Series

Author

Markov, G., University Hospital „Aleksandrovska' ‒ Sofia, Andonova, N., Zdravkov, Y, Petrova, E., and Oscar, A.

Subjects
genetic structures, Ocular syphilis, рlacoid chorioretinitis, panuveitis, neuroretinitis, vasculitis, treatment, sense organs, eye diseases
Abstract

Aim: To present the ocular findings in six male patients with ocular syphilis. Materials and methods: Retrospective study on six patients with ocular syphilis, admitted to UH "Aleksandrovska" Sofia, Bulgaria, took place. They were diagnosed with clinical and specific methods. The study period was from March 2017 until March 2021. We used descriptive statistical methods. Results: Three of the patients had acute posterior placoid horioretinitis, two of whom had panuveitis. Another two had panuveitis with segment occlusive periphlebitis and neuroretinitis. One of them had macular edema. Despite antibiotic treatment, the patients had residual atrophic changes in the macular regions. The sixth patient had bilateral atrophy of the optic nerves, associated with neurolues. Two of the patients had complications after receiving treatment with local, systemic and periocular corticosteroids. One of them had deterioration of ocular status and visual acuity. The other patient suffered unilateral evisceration and prosthesis after secondary glaucoma. His other eye had a complicated cataract and atrophic changes of the macula and the optic nerve disc as a result of secondary glaucoma and occlusive vasculitis. WHO recommends that ocular syphilis be treated as neurosyphilis. Our patients improved clinically after treatment with Penicillin G, Doxycycline, Ceftriaxone and Tetracycline. Only the patient with optic atrophy did not improve. One of our cases with placoid chorioretinitis had a spontaneous improvement. Conclusion: In the antibiotic era, syphilis is considered a rare disease, but its frequency has been increasing since 2001. In uveitis of unknown cause, we should keep syphilis in mind as a differential diagnosis. Ocular syphilis is usually accompanied with neurosyphilis and is an indication of testing CSF and undertaking treatment regimen for neurosyphilis. Misdiagnosed and untreated ocular syphilis can have potentially disastrous effects on vision and life prognosis.

Published
2022

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