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손현우,이지은 대한안과학회 2019 대한안과학회지 Vol.60 No.7
Purpose: To report a case of frosted branch angiitis (FBA) associated with Epstein-Barr virus (EBV) infection in a child. Case summary: A 7-year-old boy presented with bilateral blurred vision. On ophthalmic examination, his best-corrected visual acuity was 20/25 in the right eye and 20/32 in the left eye. The pupils were equal, round, and reactive to light without a relative afferent pupillary defect. He had normal color vision in both eyes. Slit-lamp examination revealed no abnormalities in the anterior parts of the eyes. Fundoscopic examination revealed prominent white sheathing retinal vasculitis predominantly on the veins in all quadrants, as well as macular edema and irregular foveal reflex in both eyes. Fluorescein angiography showed normal blood flow, but late diffuse staining and leakage of the affected vessels. Spectral domain optical coherence tomography (SD-OCT) showed thickening of the vessel walls, swelling due to hyperreflective material, and hyperreflective retinal depositions. Serological tests and the serum polymerase chain reaction for EBV were positive. A diagnosis of FBA associated with EBV was made. He was treated with systemic acyclovir and steroids. The response was rapid, with improvement in visual acuity to 20/20 in both eyes by day 3. After 7 weeks, all clinical signs resolved and SD-OCT examination showed normal vessel wall thickness and the absence of hyperreflective depositions. Conclusions: EBV may present with FBA even in the absence of a systemic sign of primary EBV infection. Thus, EBV should be considered as the etiology of FBA. 목적: 엡스타인-바 바이러스(Epstein-Barr virus, EBV) 감염에 의한 언가지혈관염을 경험하여 이를 보고하고자 한다. 증례요약: 7세 남아가 양안 시야 흐림으로 내원하였다. 최대교정시력 우안 0.8, 좌안 0.6, 안저검사상 양안 후극부에서 주변부까지 망막혈관, 주로 정맥 주위에 언가지 모양의 초형성을 보였고, 형광안저혈관조영에서 후기에 초형성된 혈관의 형광염색과 누출이 관찰되었다. Spectral domain optical coherence tomography (SD-OCT)에서 병변 혈관벽의 비후 및 혈관주위 고반사 음영의 침착물이 관찰되었다. EBV 바이러스캡시드항원 Immunoglobulin G 상승 및 혈청 바이러스 중합효소 연쇄반응검사에서 EBV 양성을 보여 EBV 에 의한 언가지혈관염을 진단하였다. Acyclovir 및 스테로이드 투약 3일째 양안 최대교정시력이 1.0으로 호전되었다. 망막혈관은 치료 7주 후 정상으로 회복되었고, SD-OCT상의 혈관벽 비후 및 혈관주위 침착물도 소실되었다. 결론: EBV 감염은 일차 감염의 전신 증상 없이 언가지혈관염으로 발현될 수 있으므로, 언가지혈관염의 드문 원인으로 고려해야 할 것으로 생각된다.
Al-Si-Mg합금에서 Mg함량과 주조응고 후 냉각속도가 T5 처리시 기계적 특성에 미치는 영향
손현우,구태민,조영희,이정무 대한금속·재료학회 2023 대한금속·재료학회지 Vol.61 No.7
The effects of Mg content and cooling rate on the T5 treatment of Al-Si-Mg alloys have beeninvestigated using Avrami kinetics and transmission electron microscopy. The alloys were super-heated at800 oC for 1 hr followed by degassing treatment at 720 oC for 15 min, and poured into a metallic mold preheatedto 250 oC. The as-cast alloys were then T5-treated at a temperature of 190 oC. As the Mg content and/or cooling rate increased, the strength of the T5-treated alloys increased while the elongation decreased overthe entire aging time. However, some T5 treatment conditions were effective to at enhancinge elongation aswell as strength. The alloy with low Mg content showed excellent elongation in the early stage of aging. B,but as the aging time increased, h. However, the elongation decreased rapidly so that there was showed nosignificant difference from with the alloy with high Mg content in the over-aging stage. This was due to acoarse and agglomerated precipitate structure, which were likely to be formed by the rapid precipitation andagglomeration of the β′ phase. The alloy with a high cooling rate exhibited superior strength with similarelongation over the entire aging time compared to the slowly cooled alloy. The reason for the decrease instrength for in the slowly cooled alloy was attributed to the coarsening of precipitates and suppression of theformation of fine precipitates during cooling.