• 대한두경부종양학회지
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• 제19권1호
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• pp.16-20
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• 2003

Objectives: Radiotherapy is an effective treatment in the initial management of T1 glottic carcinoma, but local recurrent or residual tumor growth is found in approximately 10% of the patients. Even in recurrence or residual tumor, in highly selected cases, conservation surgery with preservation of a portion of the larynx is feasible. So we investigated the efficacy of salvage vertical partial laryngectomy for recurrent glottic carcinoma after irradiation. Material and Methods: Retrospectively we reviewed a consecutive series of 10 patients treated by conservative vertical partial laryngectomy of the larynx for radiation-failure, recurrent T1 glottic squamous cell carcinoma treated at Severance Hospital from 1994 to 2002. Results: Local recurrence developed in 4 patients (40%). Two patient was salvaged by further totallaryngectomy. Successful salvage was achieved finally in 8 (80%) of the 10 patients. There was no operative mortality. Postoperative perichondritis was developed in two patients. One was resolved by conservative treatment, but the other has underwent the total laryngectomy. Conclusion: A vertical partial laryngectomy in case of recurrent glottic carcinoma after a course of irridation should be the therapy of choice when stringent criteria are observed.

• 셀메드
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• 제11권1호
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• pp.6.1-6.7
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• 2021

In situ gelling devices, as they enter the body, are dosage forms in the shape of the sol but turn into gel types under physiological circumstances. Transition from sol to gel is contingent on one or a mixture of diverse stimuli, such as transition of pH control of temperature, irradiation by UV, by the occurrence of certain ions or molecules. Such characteristic features may be commonly employed in drug delivery systems for the production of bioactive molecules for continuous delivery vehicles. The technique of in situ gelling has been shown to be impactful in enhancing the potency of local or systemic drugs supplied by non-parenteral pathways, increasing their period of residence at the absorption site. Formulation efficacy is further improved with the use of mucoadhesive agents or the use of polymers with both in situ gelling properties and the ability to bind with the mucosa/mucus. The most popular and common approach in recent years has provided by the use of polymers with different in situ gelation mechanisms for synergistic action between polymers in the same formulation. In situ gelling medicine systems in recent decades have received considerable interest. Until administration, it is in a sol-zone and is able to form gels in response to various endogenous factors, for e.g elevated temperature, pH changes and ions. Such systems can be used in various ways for local or systemic supply of drugs and successfully also as vehicles for drug-induced nano- and micro-particles. In this review we will discuss about various aspects about use of these in situ gels as novel drug delivery systems.

• Journal of Periodontal and Implant Science
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• 제52권1호
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• pp.39-53
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• 2022

Purpose: This study evaluated the systemic and local effects of doxycycline (DOX) and low-intensity laser (LIL) treatment as adjuvants to scaling and root planing (SRP) in the treatment of experimental periodontitis in rats. Methods: The sample consisted of 180 male rats (Rattus norvegicus albinus, Wistar), of which 30 did not receive induction of periodontal disease (negative control [NC] group) and 150 received induction of periodontal disease in the lower first molar. After 7 days, the ligature was removed, and the animals were divided into the following groups: NT (no treatment), SRP (SRP), DOX (SRP and DOX irrigation), LIL (SRP and laser irradiation), and DOX+LIL (SRP, DOX, and LIL). The animals were euthanized at 7, 15, and 30 days; thereafter, biochemical, radiographic, histological, and immunohistochemical analyses were performed. Results: In the intragroup analysis, lower concentrations of α-1-glycoprotein acid (α-1-Ga) and complement 3 (C3) were observed in the DOX+LIL group than in all other groups at all time points, as well as lower levels of complement 4 (C4) at 15 and 30 days (P<0.001). Less bone loss was observed in the DOX, LIL, and DOX+LIL groups than in the NC and SRP groups at all time points (P<0.001). There was a smaller number of tartrate-resistant acid phosphatase (TRAP)-positive cells in the DOX+LIL group than in the other groups at all time points (P<0.001). Positive correlations were observed between the systemic levels of α-1-Ga, C3, and C4 and the number of TRAP-positive cells. Conclusions: The combination of DOX with LIL as SRP adjuvants was effective both systemically and locally for the treatment of experimental periodontitis in rats.

• Radiation Oncology Journal
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• 제19권2호
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• pp.95-99
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• 2001

목적 : 뇌수막종 환자에서 수술후 방사선치료의 효과를 평가하고 최적의 방사선치료 방법을 알아보고자 함이 본 연구의 목적이다. 대상 및 방법 : 1988년 2월부터 1999년 11월까지 본원에서 뇌수막종으로 수술후 방사선치료를 받은 33명의 환자를 후향적으로 분석하였다. 환자의 나이는 17세부터 68세이었고 중앙값은 53세이었다. 조직학적 분류는 33명의 환자중 이행성이 15명, 수막성이 10명, 혈관주위세포성이 4명, 이형성이 3명, 악성이 1명이었다. 4명은 조직검사만을, 29명은 완전절제술을 시행하였다. 5~7주에 걸쳐 50~60 Gy를 28~35회에 나누어 조사하였다. 추적기간은 12개월~8년이었다. 결과 : 전체 환자에서 5년 및 7년 실질 생존율은 각각 78% 및 67%이었다. 5년 및 7년 무병생존율은 각각 73% 및 61%이었다. 국소제어율은 5년에 83%이었다. 25명의 양성군 환자중 1명만이 국소재발을 나타내었고, 8명의 악성군 환자중 4명이 국소재발을 나타내었다. 조직검사만을 시행한 환자에서 2명이 재발하였고 완전절제술을 시행한 29명의 환자에서 3명이 재발하였다. 조직검사만을 시행한 환자와 완전절제술을 시행한 환자의 생존율은 유의한 차이가 없었다. 60세 미만의 환자가 60세 이상의 환자보다 나은 생존율을 나타내었으나, 이는 통계적으로 유의하지 않았다. 결론 : 수술만을 시행한 환자와 비교하여 수술후 방사선치료를 시행한 환자에서 생존율이 향상됨을 알 수 있었고 뇌수막종 환자에서 수술 후 방사선치료가 안전하고 효과적인 치료방법이라 평가하였다.

• Radiation Oncology Journal
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• 제9권1호
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• pp.73-79
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• 1991

1980년 1월부터 1988년 9월사이에 연세대학병원, 연세암센터 치료방사선과 및 이비인후과에서 치료받았던 68예의 T3, T4병기의 성문암 환자를 대상으로 후향적분석을 하였다. 이 중 34명은 방사선 치료 단독으로 치료하였고 34명은 성문절제술후 방사선치료를 하였으며 이들 환자의 최소 추적기간은 2년이었고 54명 $(79\%)$에서 5년 추적조사가 가능하였다. 치료후 국소관해율은 방사선치료 단독군에서는 $51\%$, 수술 및 수술후 방사선치료군에서는 $79\%$이었고 임파절 음성군에서는$72\%,\;76\%$였으며 임파절 양성군에서는$31\%,\;81\%$이었다. 이들의 치료실패요인은 대부분 국소 국한적 이었고 30명 $(44\%)$에서 관찰되었다. 치료에 따른 5년 생존율은 방사선치료 단독군에서는 $37\%$, 수술 및 수술후 방사선치료군에서는 $76\%$로서 T3, T5병기의 성문암환자에 있어서 수술시 행후 방사선치료를 병용하는 복합요법 이 더 좋은 치료결과를 얻을 수 있음을 알았다. 그러나 임파절 음성군에서는 방사선치료 단독군과 수술 및 수술 후 방사선치료군을 비교해 본 결과 5년 생존율이 $55\%$와 $73\%$로 통계학적으로 유의한 차이를 보이지는 않았다. 따라서 본 저자들은 T3, T4병기의 성문암치료시 수술 및 방사선치료 병용요법이 더 좋은 치료결과 를 얻을 수 있지만 임파절 음성군에서는 기능적인 보존측면에서 방사선치료가 일차적 차료방법으로서 효과적이리라 사료된다.

• Journal of Advanced Marine Engineering and Technology
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• 제33권2호
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• pp.322-329
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• 2009

Machinability of LAM(Laser Assisted Machining) has been studied for ceramics such as $Al_2O_3$, $Si_3_N4$ and $ZrO_2$ by $CO_2$ laser. It was possible to remove ceramics by PCBN tool because material became softening and deterioration by local laser beam irradiation. The advantage of LAM is the ability to produce larger material removal rates and tool life. But, for cutting of $Al_2O_3$ and $ZrO_2$, stage of laser power control was needed owing to thermal shock with high temperature of workpiece by laser power. And when $Si_3N_4$ was machined by LAM, $N_2$ gas spouted from surface of one cause of high temperature. Characteristics of LAM were analyzed using pyrometer, dynamometer, SEM and EDS to measure temperature of workpiece surface, cutting force, variation of machining surface and structure of lattice respectively. As the result of this study, it was found that machinability of LAM for ceramics in $CO_2$ laser and mechanism of LAM was different according to the kind of ceramics because of properties of materials.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.1213-1218
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• 2004

The present article reports extensive numerical results on the non-local characteristics of ultra-short pulsed laser-induced breakdowns of fused silica ($SiO_{2}$) by using the multivariate Fokker-Planck equation. The nonlocal type of multivariate Fokker-Planck equation is modeled on the basis of the Boltzmann transport formalism to describe the ultra-short pulsed laser-induced damage phenomena in the energy-position space, together with avalanche ionization, three-body recombination, and multiphoton ionization. Effects of electron avalanche, recombination, and multiphoton ionization on the electronic transport are examined. From the results, it is observed that the recombination becomes prominent and contributes to reduce substantially the rate of increase in electron number density when the electron density exceeds a certain threshold. With very intense laser irradiation, a strong absorption of laser energy takes place and an initially transparent solid is converted to a metallic state, well known as laser-induced breakdown. It is also found that full ionization is provided at intensities above threshold, all further laser energy is deposited within a thin skin depth.

• Journal of Korean Neurosurgical Society
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• 제55권1호
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• pp.40-42
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• 2014

A correlation between radiation therapy and cavernoma has been suspected since 1994. Since then, only a few cases of radio-induced cavernomas have been reported in the literature (85 patients). Most of them were children, and the most frequent original tumour had been medulloblastoma. The authors report a case of two cystic cavernous angiomas after radiation therapy for atypical meningioma in adult woman. This is the first case of cavernous angioma after radiotherapy for low grade meningioma. A 39-year-old, Latin american woman was operated on for a frontal atypical meningioma with intradiploic component and adjuvant radiotherapy was delivered (6000 cGy local brain irradiation, fractionated over 6 weeks). Follow-up MR imaging showed no recurrences of the tumour and no other lesions. Ten years later, at the age of 49, she consulted for progressive drug-resistant headache. MR imaging revealed two new well defined areas of different signal intensity at the surface of each frontal pole. Both lesions were surgically removed; the histopathological diagnosis was cavernous angioma. This is the first case of cavernous angioma after radiation therapy for atypical meningioma : it confirms the development of these lesions after standard radiation therapy also in patients previously affected by non-malignant tumours.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.1096-1099
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• 2001

The basic design structure of RC-GCTs (Reserve-Conducting Gate-Commutated Thyristors) is firstly given in this paper. The bulk of wafer is punch-through (PT) type with high resistivity and narrow N-base width. The photo-mask was designed upon the turn-off characteristics of GCT and solution of separation between GCT and diode part. The center part of Si wafer is free-wheeling diode (FWD) and outer is GCT part which has 240 fingers totally. The switching performance of GCT was investigated by Dessis of ISE. The basic manufacture process of 2500V-4500V RC-GCTs was given in this work. Additionally, the local carrier lifetime control by 5Mev proton irradiation was adopted so as to not only to have the softness of reverse recovering for FWD but for reduction of turn-off losses of GCT as well.

• Nuclear Engineering and Technology
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• 제41권8호
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• pp.1109-1114
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• 2009

The evolution of a high burnup structure (HBS) in a light water reactor (LWR) $UO_2$ fuel was simulated using the Potts model. A simulation system for the Potts model was defined as a two-dimensional triangular lattice, for which the stored energy was calculated from both the irradiation damage of the $UO_2$ matrix and the formation of a grain boundary in the newly recrystallized small HBS grains. In the simulation, the evolution probability of the HBS is calculated by the system energy difference between before and after the Monte Carlo simulation step. The simulated local threshold burnup for the HBS formation was 62 MWd/kgU, consistent with the observed threshold burnup range of 60-80 MWd/kgU. The simulation revealed that the HBS was heterogeneously nucleated on the intergranular bubbles in the proximity of the threshold burnup and then additionally on the intragranular bubbles for a burnup above 86 MWd/kgU. In addition, the simulation carried out under a condition of no bubbles indicated that the bubbles played an important role in lowering the threshold burnup for the HBS formation, thereby enabling the HBS to be observed in the burnup range of conventional high burnup fuels.