• 대한물리의학회지
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• 제10권2호
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• pp.89-94
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• 2015

PURPOSE: The aim of this study was to determine the effect of device considering Mckenzie type for the subjects with forward head posture (FHP). METHODS: The subjects were 35 patients with FHP (mean age was $23.7{\pm}2.8$ years; mean height; $172.1{\pm}11.7$, mean weight; $65.8{\pm}13.9$, mean NDI(Neck Disability Index; $3.7{\pm}3.2$, mean FHP; $6.7{\pm}2.2$). We measured the posture with the Body style S-8.0(LU Commerce, South Korea) to evaluate the FHP. We collected the surface EMG(Myosystem 1400, Noraxon, USA) data to quantify changes in normalized activation levels of muscles in SternoCleidoMastoid muscle(SCM), Scalenus Anterior(SA), Trapezius upper fiber(TU) and Splenius Cervicis(SC), during the subjects were instructed to glide their head into a "chin-in" position for a retraction without and with device. RESULTS: The condition with device significantly decreased the %RVC of SA($90.84{\pm}40.54$), SCM($74.98{\pm}43.65$) and TU($67.60{\pm}47.83$) compared to the condition without device(SA;$100.39{\pm}56.32$, SCM;$119.03{\pm}109.26$, Trapezius;$80.55{\pm}39.27$). But the %RVC of capitis($65.87{\pm}47.83$) with device was increased($70.82{\pm}52.78$). There was significant difference in the %RVC between SCM and Trapezius muscle in two conditions. CONCLUSION: New device for FHP reduces the EMG activities of the TU, SCM and SA muscle. We have to develop the function of feedback to facilitate the motion in the future.

• 대한임상검사과학회지
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• 제43권1호
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• pp.19-25
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• 2011

The purpose of this study was to analyse brainstem auditory evoked potentials (BAEP) wave change data during microvascular decompression (MVD). The nerve function of Cranial Nerve VIII is at risk during MVD. Intraoperative monitoring of BAEP can be a useful tool to decrease the danger of hearing loss. Between January and December 2009, 242 patients had MVD for hemifacial spasm (HFS) and trigeminal neuralgia (TN). Among intraoperative BAEP changes, amplitude of V-V' was the most frequently observed during cerebellar retraction and decompression step of the MVD procedure. 138 patients (57%) had no BAEP change while 104 patients (42.98%) had BAEP change. 69 patients (28.5%) had Type A-I, 16 patients (6.6%) had Type A-II, 5 patients (2.1%) had Type B, and 13 patients (5.37%) had Type C. MVD is a surgical procedure to relieve the symptoms (e.g. pain, muscle twitching) caused by compression of a nerve by an artery or vein. During BAEP intraoperative monitoring, the surgical step is important in interpreting the changes of wave V. Several potential mechanisms of injury may affect the cochlear nerve, and complete loss of BAEP is often associated with postoperative hearing loss. Intraoperative BAEP monitoring may provide an early warning of hearing disturbance after MVD.

• Journal of Korean Neurosurgical Society
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• 제30권sup1호
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• pp.73-78
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• 2001

Objective : Intraoperative rupture of an intracranial aneurysm can interrupt a microsurgical procedure and jeopardize the patient's chance to favorable outcome. The purpose of this study was to analyse and evaluate intraoperative aneurysmal rupture and render ideal prevention and management to intraoperative rupture. Patients and Methods : The authors retrospectively analysed the results of 609 patients who underwent cerebral aneurysm surgery from January 1991 to December 2000. Results : 1) Intraoperative aneurysmal rupture occurred in 73 of 609 consecutive aneurysm surgery, so the incidence was about 12.0% and it was relatively lower than other reports. 2) Aneurysms arising from anterior communicating artery appeared more prone to intraoperative rupture. 3) The size of aneurysm and timing of operation didn't influence intraoperative aneurysmal rupture and temporary clipping didn't reduce the incidence of intraoperative aneurysmal rupture. 4) Intraoperative aneurysmal rupture occured during three specific periods : (1) dissection stage in 61%, (2) clip application stage in 29 %, (3) predissection stage in 10%. 5) In the patients with intraoperative aneurysmal rupture, surgical outcome was relatively good and there was no significant difference in outcome compared with unruptured group. Conclusion : Our suggestion for prevention methods of intraoperative aneurysmal rupture are as follows : 1) minimal brain retraction, 2) sharp and careful aneurysmal neck dissection, 3) gentle clipping with proper clip selection etc. Management methods after intraoperative aneurysmal rupture are as follows : 1) strong aspiration of bleeding point, 2) rapid application of temporary and/or tentative clip, 3) following rapid dissection of neck and proper clip application, 4) use of encircling clip etc.

• Journal of Korean Neurosurgical Society
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• 제30권sup2호
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• pp.197-202
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• 2001

Objective : The purpose of this study is to evaluate and compare surgical results of pterional(fronto-temporal) approach and interhemispheric approach for the high positioned anterior communicating artery aneurysm with our surgical experience. Methods : During the period between May 1990 and May 2001, 263 anterior communicating aneurysms were treated at the department of neurosurgery of Dong-A university hospital. Among them, 175 patients were operated by same operator. Thirty six out of the 175 cases were high positioned anterior communicating artery aneurysms located more than 15mm above the anterior clinoid process. Results : Pterional approaches were applied in 32 cases and interhemispheric approaches were applied in 4 cases of total 36 cases of the high positioned anterior communicating artery aneurysms. The 32 cases of pterional approach resulted in Good Recovery 20/32(63%), Moderate Disability 6/32(19%), Severe Disability 4/32(12%) and Dead 2/32(6%), and 4 cases of interhemispheric approach resulted in GR 3/4(75%) and MD 1/4(25%). Relatively, pterional approach showed poorer result on high positioned anterior communicating artery aneurysm located more than 19mm above the anterior clinoid process with GR 5/13(39%), MD 3/13(23%), SD 3/13(23%) and Dead 2/13(15%). Conclusion : Interhemispheric approach is preferable to pterional approach for certain cases of high positioned anterior communicating artery aneurysm located more than 19 mm above the anterior clinoid process because it provides adequate orientation to the regional anatomy, less retraction of frontal lobe and preservation of the olfactory tract and gyrus rectus without any surgical complications.

• Journal of Korean Neurosurgical Society
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• 제30권sup1호
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• pp.128-132
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• 2001

뇌기저동맥 체간부에 존재하는 동맥류는 매우 희귀하며 그 수술적 치료는 복잡한 해부학적 구조와 근접해있는 중요한 신경혈관 구조때문에 수술적 접근이 매우 어려운 부위이다. 산화 단층촬영과 자기공명영상의 발달은 두개저 병변을 정확히 진단할 수 있게 하였고 두개저 부위의 수술적 접근에 많은 발전을 가져오게 하였다. 뇌기저동맥 체간부에 존재하는 동맥류의 수술 방법중의 하나로 저자들은 소뇌와 측두엽의 견인이 적어 소뇌 부종을 극소화 할 수 있고 와우, 미로, 안면신경등의 구조물을 보존하여 청력손실, 안면신경마비등의 합병증이 없고 횡정맥동, S상정맥동의 보존뿐만 아니라 Labbe's 정맥을 보존할 수 있으며 수술시야가 비교적 좋은 장점들이 있는 후미로 전S상정맥동 경천막을 통한 추체로접근법을 이용하여 뇌기저동맥 체간부에 발생한 동맥류의 직접 결찰수술을 시행하여 좋은 결과를 얻었기에 문헌고찰과 함께 보고하는 바이다.

• Journal of Korean Neurosurgical Society
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• 제38권6호
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• pp.431-434
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• 2005

Objective : Subarachnoid hemorrhage[SAH] is commonly associated with polyuria [solute diuresis or water diuresis]. The authors investigate the incidence and clinical characteristics of polyuria with special reference to the administration of osmotic diuretics. Methods : One hundred and forty eight patients with high urine output [>200ml/hr] after ruptured cerebral aneurysm operated early from Jan 1998 to Jun 2003 were selected. Water diuresis [diabetes insipidus, DI] was differentiated from solute diuresis by lower urine specific gravity [<1.005] and higher plasma osmolality. The incidence and mode of onset of polyuria were compared between two types of diuresis. Additionally, the relationships between development of polyuria and clinical features including aneurysm location, clinical grade, Fisher grade, and outcome were analyzed. Osmotic diuretics were not routinely used in patients with Hunt-Hess grade I-III since July 2001. Results : Annual incidence of polyuria decreased markedly since July 2001 : 45.2% in 1998, 34.5% in 2001, 11.9% in 2003. Postoperative DI occurred in $2.4{\sim}11.1%$. DI developed mainly from ruptured anterior communicating artery aneurysm. The mean interval between the last SAH and the onset of DI was 7.1 days [range $1{\sim}27$ days] and lasted mean 4.6 days. When compared with solute diuresis, the development of DI was significantly delayed. Other clinical features were not closely related to polyuria. Conclusion : Uncontrolled polyuria may lead to cerebral ischemia and electrolyte imbalance because SAH patients are already predisposed to hypovolemia, and will risk precipitating the opposite situation with overhydration. We can decrease the development of polyuria without routine use of osmotic diuretics, by avoiding the increased intracranial pressure such as the intraoperative ventriculostomy and gentle brain retraction in good grade patients.

• Journal of Korean Neurosurgical Society
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• 제43권2호
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• pp.90-96
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• 2008

Objective: Delayed ischemic deficit or cerebral infarction is the leading cause of morbidity and mortality after aneurysmal subarachnoid hemorrhage (SAH). The purpose of this study is to reassess the prognostic impact of intraoperative elements, including factors related to surgery and anesthesia, on the development of cerebral infarction in patients with ruptured cerebral aneurysms. Methods: Variables related to surgery and anesthesia as well as predetermined factors were all evaluated via a retrospective study on 398 consecutive patients who underwent early microsurgery for ruptured cerebral aneurysms in the last 7 years. Patients were dichotomized as following; good clinical grade (Hunt-Hess grade I to III) and poor clinical grade (IV and V). The end-point events were cerebral infarctions and the clinical outcomes were measured at postoperative 6 months. Results: The occurrence of cerebral infarction was eminent when there was an intraoperative rupture, prolonged temporary clipping and retraction time, intraoperative hypotension, or decreased $O_2$ saturation, but there was no statistical significance between the two different clinical groups. Besides the Fisher Grade, multiple logistic regression analyses showed that temporary clipping time, hypotension, and low $O_2$ saturation had odds ratios of 1.574, 3.016, and 1.528, respectively. Cerebral infarction and outcome had a meaningful correlation (${\gamma}$=0.147, p=0.038). Conclusion: This study results indicate that early surgery for poor grade SAH patients carries a significant risk of ongoing ischemic complication due to the brain's vulnerability or accompanying cardio-pulmonary dysfunction. Thus, these patients should be approached very cautiously to overcome any anticipated intraoperative threat by concerted efforts with neuro-anesthesiologist in point to point manner.

• 분석과학
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• 제32권5호
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• pp.173-184
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• 2019

As the size of semiconductors becomes smaller, it is necessary to perform high precision polishing of nanoscale. Ceria, which is generally used as an abrasive, is widely used because of its uniform quality, but its stability is not high because it has a high molecular weight and causes agglomeration and rapid precipitation. Such agglomeration and precipitation causes scratches in the polishing process. Therefore, it is important to accurately analyze the size distribution of ceria particles. In this study, a study was conducted to select dispersants useful for preventing coagulation and sedimentation of ceria. First, a dispersant was synthesized and a ceria slurry was prepared. The defoamer selection experiment was performed in order to remove the air bubbles which may occur in the production of ceria slurry. Dynamic light scattering (DLS) and asymmetrical flow field-flow fractionation (AsFlFFF) were used to determine the size distribution of ceria particles in the slurry. AsFlFFF is a technique for separating nanoparticles based on sequential elution of samples as in chromatography, and is a useful technique for determining the particle size distribution of nanoparticle samples. AsFlFFF was able to confirm the presence of a little quantities of large particles in the vicinity of 300 nm, which DLS can not detect, besides the main distribution in the range of 60-80 nm. AsFlFFF showed better accuracy and precision than DLS for particle size analysis of a little quantities of large particles such as ceria slurry treated in this study.

• Elastomers and Composites
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• 제40권2호
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• pp.112-118
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• 2005

실란 커플링제가 카본블랙과 점토로 보강된 천연 고무 가황물의 회복 특성에 미치는 영향에 대해 연구하였다. Bis-(3-(triethoxysilyl)-propyl)-tetrasulfide (TESPT)를 실란 커플링제로 사용하였다. 실란 커플링제가 함유된 가황물은 실란 커플링제가 함유되지 않은 가황물에 비해 전반적으로 빠른 회복 거동을 보였다. 그러나, 점토 함량이 높은 가황물의 경우 $-20^{\circ}C$보다 낮은 온도에서는 실란 커플링제가 함유된 가황물이 실란 커플링제가 함유되지 않은 가황물에 비해 느리게 회복되었다. 실란 커플링제가 함유된 가황물과 실란 커플링제가 함유되지 않은 가황물의 회복량 차이는 점토 함량이 증가할수록 감소하였다. 실험 결과는 가교 밀도, 모둘러스, 그리고 결합 고무량으로 설명하였다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제23권2호
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• pp.1-14
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• 2018

The recent increase in demand for lithium has led to the development of new brine prospects, The brines are hosted in closed salar basin aquifers of two types that are mature halite salars and immature clastic salars. Salar brines also contain other elements of commercial interest, most notably potassium and boron. As a result, there has been a plethora of new exploration projects focused on the brines hosted in the aquifers of the intermontane-closed basins. The estimate of lithium resources and reserves in these salars depends on a detailed knowledge of aquifer geometry, porosity, and brine grade. Because the resource is in a fluid state, it has the propensity to move, mix, rearrange itself relatively rapidly during the course of a project lifetime, and lower recovery factors compared with most metalliferous and industrial mineral deposits due to reliance on pumping of the brine from wells for extraction. This is unlike any other type of metallic mineral resource and hence a different approach specially focusing on hydrogeology and brine hydrology is required for these prospects.