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  • Yayın
    Schwannoma of the lower limb: a case report
    (Springer Nature, 2024-08-11) Kutalia, Nikolozi; Bolkvadze, Magda; Erdem, Mehmet Nuri
    Schwannoma is a benign tumor of the peripheral nerve sheath and is a unique clinical entity when localized to a lower limb. Growing as a painless nodule, it might be misdiagnosed by many medical professionals as another benign soft tissue skin condition, such as lipoma, myxoma, or ganglion cyst. Definitive diagnosis of peripheral schwannoma is made by biopsy and histopathologic evaluation, followed by surgical excision, which is the definitive treatment of the tumor. Classic symptoms of schwannoma of the lower limb are peripheral neuropathy (tingling, burning sensations) and motor impairment (weakness, paralysis of the affected limb). MRI imaging and biopsy are the most useful diagnostic methods for peripheral schwannoma, followed by surgical excision, which is the treatment of choice. Postoperative complications, if present, are minimal and rare. Because of the slow-growing nature of the tumor and the complexity of the lower limb's nervous and structural network, it is often asymptomatic and is challenging to diagnose at a primary stage. That is why we want to spread awareness and draw the reader's attention to this rare case of a patient with schwannoma on the left lower limb.
  • Yayın
    Surfaces with constant Gaussian and mean curvatures N the anti-de Sitter space H31
    (Honam Mathematical Soc, 2024-06) Dursun, Uğur
    In this work, we study time-like and space-like surfaces invariant by a group of translation isometries of the half-space model H31 of the anti-de Sitter space H31. We determine all such surfaces with constant mean curvature and constant Gaussian curvature. We also obtain umbilical surfaces of H31.
  • Yayın
    Effect of modulated anodal stimulation over the dorsolateral prefrontal cortex on working memory: a preliminary study
    (Istanbul University, 2025-12-31) Küçük, Zeynep; Erdoğan, Ezgi Tuna; Kurt, Adnan; Karamürsel, Sacit
    Objectives: Working memory has two components: temporary storage and manipulation of the information necessary for cognitive behavior through the central executive system. This study aimed to investigate the effects of modulated anodal transcranial direct current stimulation (mtDCS) of the dorsolateral prefrontal cortex on working memory. Materials and Methods: Twelve volunteers without neurological or psychiatric disorders and without drug use participated. Working memory performance was assessed with a visual 3-back task using consonant letters during stimulation. A 20/minute training session was conducted to facilitate learning, and participants who achieved an accuracy rate of 50% or higher proceeded to the main experiment. Four stimulation conditions were applied, each lasting 10 minutes: mtDCS-11 Hz and mtDCS-22 Hz (1.70 mA offset, 0.35 mA peak/to/peak), direct current (DC) (2 mA), and sham. Reaction times and total correct responses were recorded. Results: Statistical analysis of the left dorsolateral prefrontal cortex (DLPFC) stimulation revealed a significant difference in the mean numbers of correct responses among the mtDCS and transcranial direct current stimulation (tDCS) conditions, but not compared with sham. The mean number of correct responses under mtDCS-11Hz and mtDCS-22Hz was significantly lower than under DC stimulation; however the performance decrement under 11 Hz mtDCS was the most pronounced among the active conditions. Conclusion: mtDCS-11Hz and mtDCS-22Hz negated the subtle facilitation of tDCS might have provided.