Cerebellar Ganglioglioma in an Old Patient

Gangliogliomas could be found anywhere throughout the central nervous system and mainly affect children and young adults during the first three decades of life. Cerebellar gangliogliomas may be rarely found, especially in old ages. Here, we present a case of ganglioglioma of the cerebellum in an old patient. The cystic cerebellar mass was associated with calcifications, intratumoral hemorrhage without ng edema. When a cystic cerebellar mass is associated with calcifications and intratumoral hemorrhage, ganglioglioma should be included in differential diagnosis. Gangliogliomas usually have good prognoses. Radiation therapy should be deferred even in subtotally removed cases.ope

Thoracoscopic limited T-3 sympathicotomy for primary hyperhidrosis: prevention for compensatory hyperhidrosis

Objective：This study evaluates the role of thoracoscopic T3 sympathicotomy for the treatment of primary hyperhidrosis and the prevention of compensatory hyperhidrosis. Methods : Thoracoscopic T3 sympathicotomy was performed on 27 patients with either isolated palmar hyperhidrosis (n=24) or in combination with axillary hyperhidrosis (n=3), from February 1999 to February 2002. In the case of combined palmar and axillary hyperhidrosis, additional coagulation of T4 sympathetic ganglion was performed. The mean follow-up period was 26.7 months. Operative results were determined on the basis of complications, compensatory hyperhidrosis, and patient satisfaction. Results : The immediate postoperative results showed that all 24 patients with palmar hyperhidrosis reported complete alleviation of their symptoms. One patient with palmar and axillary hyperhidrosis for whom the axillary hyperhidrosis was not completely resolved underwent a second T4 sympathicotomy one month after first operation. There were two patients who suffered mild compensatory hyperhidrosis(7.4%). All 27 patients reported a high long-term satisfactory rate (average score; 7.93/10). One patient required a chest tube for treating pneumothorax. Other complications such as Horners syndrome, intercostal neuralgia, gustatory hyperhidrosis, and pulmonary edema were not observed. Conclusion : Thoracoscopic limited T3 sympathicotomy is an effective method to treat primary hyperhidrosis with a low rate of compensatory hyperhidrosis and a high rate of long-term satisfaction.ope

Microscopic mechanism of the tunable band gap in potassium-doped few-layer black phosphorus

Tuning band gaps in two-dimensional (2D) materials is of great interest for the fundamental and practical aspects of contemporary material sciences. Recently, black phosphorus (BP) consisting of stacked layers of phosphorene was experimentally observed to show a widely tunable band gap by means of the deposition of potassium (K) atoms on the surface, thereby allowing great flexibility in the design and optimization of electronic and optoelectronic devices. Here, based on density-functional theory calculations, we demonstrates that the donated electrons from K dopants are mostly localized in the topmost BP layer and this surface charging efficiently screens the K ion potential. It is found that, as the K doping increases, the extreme surface charging and its screening of K atoms shift the conduction bands down in energy, i.e., towards a higher binding energy, because they have more charge near the surface, while it has little influence on the valence bands having more charge in the deeper layers. This result provides a different explanation for the observed tunable band gap compared to the previously proposed giant Stark effect where a vertical electric field from the positively ionized K overlayer to the negatively charged BP layers shifts the conduction band minimum Gamma(1c) (valence band minimum Gamma(8v)) downwards (upwards). The present prediction of Gamma(1c) and Gamma(8v) as a function of the K doping reproduces well the widely tunable band gap, anisotropic Dirac semimetal state, and band-inverted semimetal state, as observed in an angle-resolved photoemission spectroscopy experiment. Our findings shed new light on a route for tunable band gap engineering of 2D materials through the surface doping of alkali metals.This work was supported by National Research Foundation of Korea (NRF) grants funded by the Korean Government (Grants No. 2015M3D1A1070639 and No. 2015R1A2A2A01003248). S.W. is supported by the NSFC (Grant No. U1530401). Calculations were performed by the KISTI supercomputing center through the strategic support program (KSC-2016-C3-0059) for supercomputing application research. S.W.K. acknowledges support from POSCO TJ Park Foundation

Clinical analysis of gamma knife radiosurgery for brain metastases : prognosis factor for survival and local control

의학과/석사[한글] 본 연구는 1992년 5월부터 2002년 12월까지 본원에서 전이성 뇌종양으로 감마나이프 방사선 수술을 받은 156명의 환자를 대상으로 하였으며, 모두 587개의 병변에 대해 177차례의 시술이 행하여졌다. 평균 추적관찰 기간은 11.6개월이었으며, 평균 병변의 개수는 3.4개였다. 종양의 용적은 평균 4.2cc 였으며, 방사선 수술은 평균16.2Gy의 경계 선량를 이용하여 하였다. 자료분석은 생존율에 영향을 미치는 요인과 국소완치율에 영향을 미치는 요인으로 나누어 분석하였다. 환자의 생존율은 6개월, 12개월, 24개월의 생존율이 각각 85.1%, 64.2% 47%로 나타났다. 다변량 분석에서 생존율에 통계학적으로 유의한 의미의 영향을 미치는 인자로는 초기 KPS 점수와 두개강외로의 전이 유무, 원발암의 치료상태인 것으로 나타났다. 국소완치율에 대한 분석에서는 통계학적으로 의미있는 영향을 주는 인자는 보이지 않았다. 감마나이프 방사선 수술의 국소완치율에 전뇌방사선 치료 유무는 통계학적으로 유의한 영향을 끼치지 않는 것으로 나타났다 [영문]The author analyzed 156 patients underwent gamma knife radiosurgery between May 1992 and December 2002, and conducted an analysis of prognostic factors for patient survival and local control of brain metastases after gamma knife radiosurgery. Mean follow up duration was 11.6months and mean number of lesion was 3.4. The most common primary site was lung and then breast followed. Mean tumor volume was 4.2cc and mean margin dose was 16.2Gy. In the survival analysis, 6 months, 12 months, and 24 months survival rate were 85.1%, 64.2%, and 47%, respectively. Multivariate analysis revealed that KPS score, no evidence of extracranial metastases, and controlled primary disease were significantly related to patient survival. For local control, there was no statistically significant factor. Adjuvant whole brain irradiation after Gamma knife radiosurgery also did not significant influence on the local control.ope

Hydrogen adsorption induced nanomagnetism at the Si(111)-(7 x 7) surface

The creation of magnetism on nonmagnetic semiconductor surfaces is of importance for the realization of spintronics devices. In particular, the coupling of electron spins within quantum nanostructures can be utilized for nanomagnetism applications. Here, we demonstrate, based on first-principles density-functional theory calculations, that the adsorption of H atoms on the Si(111)-(7 x 7) surface induces the spin polarization of surrounding Si dangling bonds (DBs) and their spin orderings. It is revealed that the H adsorption on a rest-atom site exhibits a Jahn-Teller-like distortion that accompanies a charge transfer from the rest atom to the nearest-neighboring adatoms. This charge transfer increases the local density of states of three such adatoms at the Fermi level, thereby inducing a Stoner-type instability to produce a ferrimagnetic order of adatom DBs around the adsorbed H atom. Meanwhile, the H adsorption on an adatom site cannot induce spin polarization, but, as adsorbed H atoms increase, the ferrimagnetic order of rest-atom DBs emerges through the charge transfer from rest atoms to adatoms. Our findings provide a microscopic mechanism of the H-induced spin orderings of Si DBs at the atomic scale, which paves the way for the design of nanoscale magnetism in the representative semiconductor surface.We are grateful for discussions with Y. Jia. This work is supported by the NSFC of China (Grants No. 11804306, No. 11674289, and No. 11504332) and National Research Foundation of Korea (NRF) funded by the Korean Government (Grants No. 2015M3D1A1070639 and No. 2016K1A4A3914691). The calculations were performed at the High Performance Computational Center of Zhengzhou University. J.-H.C. acknowledges the strategic support program (KSC-2017-C3-0080) for supercomputing application research from the KISTI supercomputing center

해양에서 나타나는 계절내 진동의 발생 및 전파 특성 연구

학위논문(석사)--서울대학교 대학원 :지구환경과학부,2001.Maste