Surface Complexation of Iron ions from Magnetite with Chelating agents

Dho, Hyon Seung 청주대학교 산업과학연구소 1997 産業科學硏究 Vol.15 No.2

자철석의 철이온과 킬레이트 시약의 계면에서의 착물 형성은 흡착 및 용출 현상에 의해 이루어진다. 자철석으로부터 철이온의 용출과 킬레이트 시약의 흡착으로 계면에서의 착물 형성시 1,10 페나트롤라인은 중성이온인 phen이, 8-퀴놀린은 중성의 HQ이온과 음이온 Q^(-)이 흡착을 주도하였다. 제타 전위 측정결과 자철석의 등전점은 pH 6.5였다. 이때, 1,10 페난트롤란인은 phen 이온에 의해 pH 9.2까지 자철석이 양으로 하전되었다. 반면에 8-퀴놀린은 등전점이 pH 5.2 이었다. 따라서, pH 6.5에서는 자철석 계면에 FeQ₂(OH)₂^(-) 착물의 형성으로 자철석이 음으로 하전되었다.

Role of Electrostatic Interaction on the Selective Separation of Oil Emulsion in Wastewater

Dho, Hyon Seung 청주대학교 산업과학연구소 2000 産業科學硏究 Vol.18 No.1

본 연구는 폐수에 용존해 있는 오일 에멀젼과 MF 여과막 표면사이의 발생하는 정전상호작용의 역할에 관한 것이다. 오일 에멀젼의 분리공정에서 파울링 현상은 여과막 표면의 흡착 뿐만아니라, 여과막의 재질 특성, 소수성화와 에멀젼의 안정성과 관계가 있었으며 단순히 여과막의 특성이 파울링에 영향을 주는 것이 아니라는 결론을 얻었다.따라서 파울링 현상은 에멀젼 안정성, 여과막의 표면성질, 계면활성제 농도의 복합적인 관계에서 발생하게 되는 것으로 나타났다. The role of electrostatic interactions between the oil emulsion and membrane surface was investigated. The fouling tendencies in the oil emulsion separation process were correlated not only the excess adsorption on the membrane surface, but also the characteristics of membrane material, hydrophobicity, and emulsion stability. It can be concluded that only membrane surface characteristics have not much influence on fouling behavior contrary to the other investigators. The fouling phenomenon, therefore, may be occurred by the inter change able relationship of the emulsion stability, membrane surface characteristics, surfactant concentrations, and physical characteristics for participating the experiments.

Optimal strategy of gamma knife radiosurgery for craniopharyngiomas

Dho, Yun-Sik,Kim, Yong Hwy,Kim, Jin Wook,Park, Chul-Kee,Chung, Hyun-Tai,Kim, Seung-Ki,Paek, Sun Ha,Wang, Kyu-Chang,Kim, Dong Gyu Springer-Verlag 2018 Journal of neuro-oncology Vol.140 No.1

Endoscopic endonasal approach for craniopharyngioma: the importance of the relationship between pituitary stalk and tumor

Dho, Yun-Sik,Kim, Yong Hwy,Se, Young-Bem,Han, Doo Hee,Kim, Jung Hee,Park, Chul-Kee,Wang, Kyu-Chang,Kim, Dong Gyu American Association of Neurological Surgeons 2018 Journal of Neurosurgery Vol.129 No.3

<B>OBJECTIVE</B><P>The endoscopic endonasal approach (EEA) is commonly used for the treatment of craniopharyngioma; therefore, it is essential to analyze outcomes in order to understand the benefits and drawbacks. The goal of this paper was to evaluate the clinical features and outcomes associated with this treatment approach.</P><B>METHODS</B><P>From July 2010 to March 2016, 82 adult craniopharyngioma patients underwent an EEA at the authors’ institution. Of these cases, intraoperative records and immediate postoperative MR images were available for 68 patients. The patients underwent systemized endocrinological evaluation. Eighteen of 68 patients who underwent EEA for recurrence or regrowth of residual lesions after previous surgical management were excluded in the analysis of the anatomical tumor classification. The authors retrospectively analyzed preoperative clinical features and previous anatomical classifications, focusing on the relationship of the pituitary stalk and tumor, to determine predictive factors for the clinical outcome, such as the extent of resection, visual function, endocrinological function, recurrence rate, and complications.</P><B>RESULTS</B><P>The mean tumor size was 2.5 cm (3.1 cm for primary tumors and 1.9 cm for recurrent lesions). Gross-total resection (GTR) was achieved in 62 (91.1%) patients (48 [96.0%] patients with primary tumors and 14 [77.8%] patients with recurrent tumors). The rate of GTR was higher in the primary group than in the group with recurrence (p = 0.038). The overall pre- and postoperative visual impairment scale (VIS) scores were 40.8 and 22.1, respectively (50.9 and 14.3 in the primary group and 30.7 and 29.9 in patients with recurrence, respectively). The improvement rate in VIS score was higher in the primary group than in the recurrent group (p = 0.001). Endocrinological function was improved in 4 patients (5.9%) and deteriorated in 32 of 68 patients (47.1%). Tumor invasion into the center of the pituitary stalk affected the postoperative outcomes most significantly. Cognitive dysfunction was observed in 22 patients before surgery and improved in 20 patients (90.9%) after surgery. Hydrocephalus was found in 7 patients and resolved after surgery in all cases. CSF leakage occurred in 2 (2.9%) of 68 patients and was repaired by revision surgery in both patients. Ten patients without CSF leakage also received antibiotics for the treatment of meningitis. The infection rate was higher in the recurrent group. Postoperative endocrinological evaluation showed no deficits in 12 patients and panhypopituitarism in 55 patients. The remaining patient had growth hormone deficiency. Forty-three patients had new-onset diabetes insipidus, and 1 patient had persistent diabetes insipidus after surgery. There were 2 (2.9%) cases of recurrence during the mean 30.7-month follow-up period; one patient underwent radiosurgery and the other underwent reoperation.</P><B>CONCLUSIONS</B><P>The EEA resulted in excellent surgical outcomes and acceptable morbidity rates, regardless of the anatomical location of the tumor. Invasion of the craniopharyngioma into the center of the pituitary stalk has strong predictive power for postoperative endocrinological outcome.</P>

Investigation of the location of atypical teratoid/rhabdoid tumor.

Dho, Yun-Sik,Kim, Seung-Ki,Cheon, Jung-Eun,Park, Sung-Hye,Wang, Kyu-Chang,Lee, Ji Yeoun,Phi, Ji Hoon Springer Verlag 2015 Child's nervous system Vol.31 No.8

<P>The location of a brain tumor is a fundamental characteristic, because various brain tumors develop in relatively specific locations. An atypical teratoid/rhabdoid tumor (AT/RT) is a highly age-specific tumor that occurs in infants and young children. However, AT/RTs develop in a variety of locations in the brain. This study aimed at uncovering the tumor location pattern of AT/RTs to enhance diagnoses.</P>

Interface Reaction and Thickness-dependent Spin-diffusion Effect in YBa2Cu3O7- /La0.7Sr0.3MnO3 Bilayers

Dho, Joonghoe,Ki, Sanghoon Korean Physical Society 2010 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.57 No.6

Catastrophic Intramedullary Abscess Caused by a Missed Congenital Dermal Sinus

Dho, Yun-Sik,Kim, Seung-Ki,Wang, Kyu-Chang,Phi, Ji Hoon The Korean Neurosurgical Society 2015 Journal of Korean neurosurgical society Vol.57 No.3

Congenital dermal sinus (CDS) is a type of occult spinal dysraphism characterized by a midline skin dimple. A 12-month-old girl presented with fever and ascending quadriparesis. She had a midline skin dimple in the upper sacral area that had been discovered in her neonatal period. Imaging studies revealed a holocord intramedullary abscess and CDS. Overlooking CDS or misdiagnosing it as benign sacrococcygeal dimple may lead to catastrophic infection and cause serious neurological deficits. Therefore, further imaging work-up or consultation with a pediatric neurosurgeon is recommended following discovery of any atypical-looking dimples in the midline.

Preliminary Evaluation of Radiological Impact for Domestic On-road Transportation of Decommissioning Waste of Kori Unit 1

Dho, Ho-Seog,Seo, Myung-Hwan,Kim, Rin-Ah,Kim, Tae-Man,Cho, Chun-Hyung Korean Radioactive Waste Society 2020 방사성폐기물학회지 Vol.18 No.4

Currently, radioactive waste for disposal has been restricted to low and intermediate level radioactive waste generated during operation of nuclear power plants, and these radioactive wastes were managed and disposed of the 200 L and 320 L of steel drums. However, it is expected that it will be difficult to manage a large amount of decommissioning waste of the Kori unit 1 with the existing drums and transportation containers. Accordingly, the KORAD is currently developing various and large-sized containers for packaging, transportation, and disposal of decommissioning waste. In this study, the radiation exposure doses of workers and the public were evaluated using RADTRAN computational analysis code in case of the domestic on-road transportation of new package and transportation containers under development. The results were compared with the domestic annual dose limit. In addition, the sensitivity of the expected exposure dose according to the change in the leakage rate of radionuclides in the waste packaging was evaluated. As a result of the evaluation, it was confirmed that the exposure dose under normal and accident condition was less than the domestic annual exposure dose limit. However, in the case of a number of loading and unloading operations, working systems should be prepared to reduce the exposure of workers.

Characteristics and high quality development of clay in Korea

Dho, Hyon-Seung(도현승) 한국호텔외식관광경영학회 2017 호텔경영학연구 Vol.26 No.4

Control of Cellular Bcl-x_L Levels by Deamidation-Regulated Degradation

Dho, So Hee,Deverman, Benjamin E.,Lapid, Carlo,Manson, Scott R.,Gan, Lu,Riehm, Jacob J.,Aurora, Rajeev,Kwon, Ki-Sun,Weintraub, Steven J. Public Library of Science 2013 PLoS biology Vol.11 No.6

<P>The cellular concentration of Bcl-x<SUB>L</SUB> is among the most important determinants of treatment response and overall prognosis in a broad range of tumors as well as an important determinant of the cellular response to several forms of tissue injury. We and others have previously shown that human Bcl-x<SUB>L</SUB> undergoes deamidation at two asparaginyl residues and that DNA-damaging antineoplastic agents as well as other stimuli can increase the rate of deamidation. Deamidation results in the replacement of asparginyl residues with aspartyl or isoaspartyl residues. Thus deamidation, like phosphorylation, introduces a negative charge into proteins. Here we show that the level of human Bcl-x<SUB>L</SUB> is constantly modulated by deamidation because deamidation, like phosphorylation in other proteins, activates a conditional PEST sequence to target Bcl-x<SUB>L</SUB> for degradation. Additionally, we show that degradation of deamidated Bcl-x<SUB>L</SUB> is mediated at least in part by calpain. Notably, we present sequence and biochemical data that suggest that deamidation has been conserved from the simplest extant metazoans through the human form of Bcl-x<SUB>L</SUB>, underscoring its importance in Bcl-x<SUB>L</SUB> regulation. Our findings strongly suggest that deamidation-regulated Bcl-x<SUB>L</SUB> degradation is an important component of the cellular rheostat that determines susceptibility to DNA-damaging agents and other death stimuli.</P><P><B>Author Summary</B></P><P>Cellular levels of the pro-survival protein Bcl-x<SUB>L</SUB> are an important determinant of cellular susceptibility to many death stimuli, including most cancer therapies. We previously showed that human Bcl-x<SUB>L</SUB> undergoes deamidation – the conversion of two neutral asparaginyl side-chains into negatively charged aspartyl side-chains – a process that occurs spontaneously but is accelerated by the treatment of tumor cells with DNA-damaging agents. Here, we show that deamidation activates a hitherto undetected signal sequence within Bcl-x<SUB>L</SUB> that targets it for degradation by a pathway involving the proteolytic enzyme calpain. This increased degradation of Bcl-x<SUB>L</SUB>, and the consequent enhanced cellular susceptibility to programmed cell death, may contribute to the ability of DNA-damaging agents to kill tumors. We also demonstrate that deamidation of Bcl-x<SUB>L</SUB> has likely been conserved from the simplest metazoans to humans, underscoring the importance of deamidation in the regulation of Bcl-x<SUB>L</SUB>.</P>