• 한국재료학회지
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• 제29권3호
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• pp.155-159
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• 2019

Surface plasmon resonance is the resonant oscillation of conduction electrons at the interface between negative and positive permittivity material stimulated by incident light. In particular, when light transmits through the metallic microhole structures, it shows an increased intensity of light. Thus, it is used to increase the efficiency of devices such as LEDs, solar cells, and sensors. There are various methods to make micro-hole structures. In this experiment, micro holes are formed using a wet chemical etching method, which is inexpensive and can be mass processed. The shape of the holes depends on crystal facets, temperature, the concentration of the etchant solution, and etching time. We select a GaAs(100) single crystal wafer in this experiment and satisfactory results are obtained under the ratio of etchant solution with $H_2SO_4:H_2O_2:H_2O=1:5:5$. The morphology of micro holes according to the temperature and time is observed using field emission - scanning electron microscopy (FE-SEM). The etching mechanism at the corners and sidewalls is explained through the configuration of atoms.

• 한국융합학회논문지
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• 제9권11호
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• pp.29-35
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• 2018

본 연구는 준 마이크로파 대역에서 슬롯(slot) 결합 커패시터 공진기를 이용하여 Nacl 수용액의 농도변화를 감지할 수 있는 고감도 센서를 제안하였다. 센서에 적용되는 공진기는 마이크로스트립 선로의 접지 면을 활용하여 유도성 슬롯(inductive slot)과 연결된 평행판 커패시터로 구성된다. 농도변화에 따른 유전특성 측정데이터를 기반으로, 농도변화가 확연히 드러나는 UHF 대역에서 공진주파수가 정해졌으며, 평행판 커패시터 내에 Nacl 수용액이 삽입된다. 시뮬레이션을 토대로 제안된 공진기를 설계하여 제작하였다. 농도 변화를 0 mg/dl에서 400 mg/dl까지 100 mg/dl 단계로 실험하였고, 전송 산란계수($S_{21}$)가 측정되었다. 실험결과 각 단계별 최소 1.8 dB($S_{21}$)의 변화를 얻음으로써 Nacl 수용액에서 농도검출 센서에 적용가능함을 입증하였다.

• 대한치과교정학회지
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• 제51권2호
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• pp.105-114
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• 2021

Objective: The purpose of this study was to evaluate the relationship between rotational disk displacement (DD) of the temporomandibular joint (TMJ) and the dentoskeletal morphology. Methods: Women aged > 17 years were included in this study. Each subject had a primary complaint of malocclusion and underwent routine cephalometric examinations. They were divided into five groups according to the findings on sagittal and coronal magnetic resonance images of their TMJs: bilateral normal disk position, bilateral anterior DD with reduction (ADDR), bilateral rotational DD with reduction (RDDR), bilateral anterior DD without reduction (ADDNR), and bilateral rotational DD without reduction (RDDNR). Twenty-three cephalometric variables were analyzed, and the Kruskal-Wallis test was used to evaluate differences in the dentoskeletal morphology among the five groups. Results: Patients with TMJ DD exhibited a hyperdivergent pattern with a retrognathic mandible, unlike those with a normal disk position. These specific skeletal characteristics were more severe in patients exhibiting DD without reduction than in those with reduction, regardless of the presence of rotational DD. Rotational DD significantly influenced horizontal and vertical skeletal patterns only in the stage of DD with reduction, and the mandible exhibited a more backward position and rotation in patients with RDDR than in those with ADDR. However, there were no significant dentoskeletal differences between ADDNR and RDDNR. Conclusions: The results of this study suggest that rotational DD of TMJ plays an important role in the dentoskeletal morphology, particularly in patients showing DD with reduction.

• Journal of Korean Neurosurgical Society
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• 제67권2호
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• pp.249-256
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• 2024

The Leksell frame-based transcerebellar approach was proposed with the arc support frame attached upside down to the Z coordinate. This study presented practical tips and considerations for obtaining adequate tissue samples for deep-seated cerebellar lesions or lower brainstem lesions specifically those accessible via the cerebellar peduncle. For practical insights, the Leksell coordinate frame G was fixed to prevent the anterior screw implantation within the temporalis muscle, to avoid interference with the magnetic resonance (MR)-adapter, and taking into account the magnetic field of MR in close proximity to the tentorium. After mounting of indicator box, the MR imaging evaluation should cover both the indicator box and the infratentorial region that deviated from it. The coordinates [X, Y, Za, Arc⁰, Ringa⁰] obtained from Leksell SurgiPlan^® software (Elekta, Stockholm, Sweden) with arc 0⁰ located on the patient's right side were converted to [X, Y, Zb=360-Za, Arc⁰, Ringb⁰=Ringa⁰-180⁰]. The operation was performed in the prone position under general anesthesia in four patients with deep cerebellar (n=3) and brainstem (n=1) tumors. The biopsy results showed two cases of diffuse large B-cell lymphoma, one metastatic braintumor and one glioblastoma. One patient required frame repositioning as a complication. Drawing upon the methodology outlined in existing literature, we anticipate that imparting supplementary expertise could render the stereotactic biopsy of infratentorial tumors more consistent and manageable for the practitioner, thereby facilitating adequate tissue samples and minimizing patient complications.

• 대한영상의학회지
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• 제82권2호
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• pp.481-486
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• 2021

내난관종은 이소성 난관 상피의 비종양적 증식으로 발생한다. 비전형적인 형태로 종괴 형태를 보여 종양성 병변과 감별을 필요로 하는 개화성 낭성 내난관종이 매우 드물게 보고되어 있다. 저자들은 복막 외 골반강과 후복막강에서 다발성으로 발생한 개화성 낭성 내난관종 증례의 영상의학적 소견을 보고하고자 한다.

• 대한영상의학회지
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• 제82권6호
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• pp.1388-1401
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• 2021

회전근개(rotator cuff) 수술 후 영상은 통증이나 장애가 수술 후 새로 발생하거나 혹은 증상이 없어도 일상적으로 시행된다. 수술 후 영상은 MRI나 초음파 등을 통해 얻으며 일반적으로 복구된 힘줄(건)의 완전성을 확인하고자 하는 것이 목적이다. MRI는 술 후 해부학적 구조 변경을 전반적으로 확인할 수 있고 수술 후 합병증 등을 객관적으로 확인할 수 있지만 여러가지 수술에 사용된 물질들이 화질을 나쁘게 하여 술 전 영상에 비하여 진단 정확도가 떨어진다. 초음파는 복구된 회전근개의 상태를 역동적으로 확인할 수 있고 회복에 사용되는 수술기구들로부터 생기는 인공물도 피할 수 있다. 영상 소견이 항상 임상 증상이나 예후와 일치하지는 않으나 재건된 건의 두께보다는 삼각근하 액체 저류가 통증과 기능 회복에 있어 중요하다. 긴장 탄성도 검사도 예후를 예측하는데 유용한 방법이 될 수 있다.

• Korean Journal of Radiology
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• 제1권1호
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• pp.11-18
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• 2000

Objective: To evaluate the hydrodynamic changes occurring in cerebrospinal fluid (CSF) flow in cervical spinal stenosis using the spatial modulation of magnetization (SPAMM) technique. Materials and Methods: Using the SPAMM technique, 44 patients with cervical spinal stenosis and ten healthy volunteers were investigated. The degree of cervical spinal stenosis was rated as low-, intermediate-, or high-grade. Low-grade stenosis was defined as involving no effacement of the subarachnoid space, intermediate-grade as involving effacement of this space, and high-grade as involving effacement of this space, together with compressive myelopathy. The patterns of SPAMM stripes and CSF velocity were evaluated and compared between each type of spinal stenosis and normal spine. Results: Low-grade stenosis (n = 23) revealed displacement or discontinuity of stripes, while intermediate- (n = 10) and high-grade (n = 11) showed a continuous straight band at the stenotic segment. Among low-grade cases, 12 showed wave separation during the systolic phase. Peak systolic CSF velocity at C4-5 level in these cases was lower than in volunteers (p < .05), but jet-like CSF propulsion was maintained. Among intermediate-grade cases, peak systolic velocity at C1-2 level was lower than in the volunteer group, but the difference was not significant (p > .05). In high-grade stenosis, both diastolic and systolic velocities were significantly lower (p < .05). Conclusion: Various hydrodynamic changes occurring in CSF flow in cervical spinal stenosis were demonstrated by the SPAMM technique, and this may be a useful method for evaluating CSF hydrodynamic change in cervical spinal stenosis.

• Clinical and Experimental Vaccine Research
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• 제11권2호
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• pp.217-221
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• 2022

Lacunar strokes occur when a branch of a large cerebral artery is blocked. The thalamus is often affected, causing uncontrollable motions. A 72-year-old previously healthy man presented with involuntary motions in the right limbs, which were present at rest, and exacerbated during voluntary actions. He had received the first dose of the adenoviral vector-based coronavirus disease 2019 vaccine (ChAdOx1 nCoV-19) 9 days ago. Severe thrombocytopenia and elevated levels of lactate dehydrogenase, ferritin, C-reactive protein, and D-dimer were found, without any evidence of connective tissue disease. Electromyography demonstrated typical choreiform movements, and the brain magnetic resonance imaging indicated a small high signal lesion on the left side of the thalamus. Detection of the immunoglobulin G antibodies against platelet factor 4 in the blood, negative heparin-induced platelet activation (HIPA) test, and positive modified HIPA test confirmed the thalamic stroke due to the vaccine-induced prothrombotic immune thrombocytopenia (VIPIT). He was admitted to the intensive care unit and received nadroparin, sodium ozagrel, edaravone, methylprednisolone, and haloperidol. His hemi-chorea improved gradually over 2 weeks, and he was discharged after 21 days with rehabilitation advice. VIPIT due to the ChAdOx1 nCoV-19 is a novel immune-mediated response that needs clinicians' awareness and further investigations.

• Korean Chemical Engineering Research
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• 제43권1호
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• pp.85-91
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• 2005

ECR-MOCVD를 이용한 상온조건에서 투명전도성 고분자막이$(CH_3)_4Sn-H_2-O_2$ 분위기하에 $SnO_2$막이 제조되었다. 제조된 투명전도막의 전기적특성은 공정압력, 전자석/분사링/기판사이의 거리, 전자석의 전류, 마이크로파 출력, 증착시간과 같은 공정변수에 따라 조사되었다. 마이크로파 출력과 전자석의 전류가 증가함에 따라 낮은 전기적 저항을 갖는 $SnO_2$막이 형성되었다. 또한 이들 공정변수들이 증착된 막의 광학적특성에 미치는 영향은 중요하게 나타났다. ECR-MOCVD에 의해 제조된 막의 투과도와 반사도는 380-780 nm의 가시광영역에서 각각 93-98%, 0.1-0.5%였다. 증착된 막의 평균 grain 크기는 공정변수에 관계없이 20-50 nm범위의 값으로 일정하였다. 본 연구의 최적화된 조건에서 전기적저항은 $7.5{\times}10^{-3}ohm{\cdot}cm$, 투과도 93%, 반사도 0.2%를 갖는 막이 얻어졌다.

• The Korean Journal of Physiology and Pharmacology
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• 제24권6호
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• pp.503-516
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• 2020

KCNQ family constitutes slowly-activating potassium channels among voltage-gated potassium channel superfamily. Recent studies suggested that KCNQ4 and 5 channels are abundantly expressed in smooth muscle cells, especially in lower urinary tract including corpus cavernosum and that both channels can exert membrane stabilizing effect in the tissues. In this article, we examined the electrophysiological characteristics of overexpressed KCNQ4, 5 channels in HEK293 cells with recently developed KCNQ-specific agonist. With submicromolar EC₅₀, the drug not only increased the open probability of KCNQ4 channel but also increased slope conductance of the channel. The overall effect of the drug in whole-cell configuration was to increase maximal whole-cell conductance, to prolongate the activation process, and left-shift of the activation curve. The agonistic action of the drug, however, was highly attenuated by the co-expression of one of the β ancillary subunits of KCNQ family, KCNE4. Strong in vitro interactions between KCNQ4, 5 and KCNE4 were found through Foster Resonance Energy Transfer and co-immunoprecipitation. Although the expression levels of both KCNQ4 and KCNE4 are high in mesenteric arterial smooth muscle cells, we found that 1 μM of the agonist was sufficient to almost completely relax phenylephrine-induced contraction of the muscle strip. Significant expression of KCNQ4 and KCNE4 in corpus cavernosum together with high tonic contractility of the tissue grants highly promising relaxational effect of the KCNQ-specific agonist in the tissue.