• Journal of Preventive Medicine and Public Health
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• 제23권3호
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• pp.262-273
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• 1990

In order to assess the method which is more sensitive one to detect the early change of lung tissue by the inhaled dust, we have performed the various medical examinations such as chest radiography, pulmonary function test, high resolution chest CT, brnchoalveolar lavage and lung biopsy used bronchoscope and ultrathin bronchoscopy examination to 48 persons. The control group were 8 persons who did not exposed to dust, 40 cases of the experimental group have professionally exposed to the mineral dust. The results were as follows 1. The total number of cells in bronchoalveolar lavage was significantly increased in all of the pneumoconiosis group classified by chest and high resolution chest CT. 2. The composition rate of macrophage to the total number of cells in bronchoalveolar lavage fluid was significantly decreased in all of the pneumoconiosis group compared with the control group. 3. The composition rate of neutophils and lymphocytes to the total number of cells in bronchoalveolar lavage fluid was significantly increased in all of the pneumoconiosis group compared with the control group. 4. The forced expiratory volume in one second ($FEV_{1-0}$), maximal mid-expiratory flow (MMF), and maximal voluntary ventilation (MVV) were significantly increased only in the group of the progressed pneumoconiosis relatively. 5. We observed submucosal edema, anthracotic pigmentation and granuloma formation in transbronchial lung biopsy of the suspected pneumoconiosis (category 0/1) case which is thought to the early change of coal workers' pneumoconiosis.

• Journal of Korean Neurosurgical Society
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• 제48권6호
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• pp.518-523
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• 2010

Objective : Chronic subdural hematoma (CSDH) is known to have a significant recurrence rate. There are different criteria defining the recurrence of CSDH. We evaluated the postoperative course of CSDH and tried to propose the reasonable criteria of recurrence. Methods : We retrospectively examined the medical records and pre- and postoperative CT scans of 149 consecutive patients who underwent surgery from January 2005 to December 2009. Diagnosis was confirmed by CT scanning or MRI. The postoperative courses were either resolved or recurrent. The resolved CSDH was one of the three types; early resolution, delayed resolution, or late resolution. The recurrent CSDH was one of the four types; recurrence without resolution, early recurrence after resolution, late recurrence after resolution, or recurrent-and-resolved type. Results : The CSDH was resolved within 30 days after surgery in 58 (39%) patients, between 1 to 3 months in 62 (42%), and after 3 months in 11 (7%) patients. The CSDH was recurred in 18 (12%) patients. Late resolution or recurrence was more common in the aged. The recurrent hematoma was seen on the same side in 11 patients, on the different side in 7 patients. Recurrence was significantly more common in the thick hematomas. Conclusion : For a working criteria of the recurrence of CSDH, we propose the early recurrence as return of symptoms or reaccumulation of the hematoma after a surgery within 3 months regardless of the location, amount or repeated operations. The late recurrence can be defined as reappearance or enlargement of a liquefied hematoma within the cranial cavity surrounded by the membranes or persistent CSDH beyond 3 months after surgery.

• Childhood Kidney Diseases
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• 제20권1호
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• pp.18-22
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• 2016

Purpose: The previous reports regarding VUR resolution were not precise due to early frequent surgical intervention. We evaluated the spontaneous resolution (SR) rate and the incidence of new renal scars in primary VUR, focusing on severe reflux. Methods: Medical records of 334 patients with primary VUR who were on medical prophylaxis without surgery for 1 to 9 years, were retrospectively reviewed. Medical prophylaxis was initiated with low-dose antibiotic prophylaxis or probiotics. Radioisotope cystourethrography was performed every 1 to 3 years until SR of reflux. New renal scar was evaluated with follow-up $^{99m}Tc$ DMSA renal scan. Results: The SR rates decreased as VUR grades were getting higher (P=0.00). The overall and annual SR were 58.4% and 14.9%/yr in grade IV reflux and 37.5% and 9.3%/yr in grade V reflux. The median times of SR were 38 months in grade IV reflux and 66 months in grade V reflux. The probable SR rates in grade IV and V reflux were 7.8% and 8.9% in the 1st year, 46.0% and 30.8% in the 3rd year and 74.4% and 64.4% in the 5th year. The incidences of new renal scars between low to moderate reflux and severe reflux showed no significant difference (P=0.32). Conclusion: The SR rates of severe primary VUR were higher than previously reported and most new renal scars were focal and mild.

• Investigative Magnetic Resonance Imaging
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• 제23권3호
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• pp.259-263
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• 2019

Although many imaging modalities can play some roles in the diagnosis of vertebral artery dissection (VAD), digital subtraction angiography (DSA) remains the gold standard method, with the highest detection rate and ability to assist in planning for endovascular treatment. However, this tool is often avoided in children because its invasive nature and it exposes them to radiation. High resolution magnetic resonance imaging (HR-MRI) have been suggested to be a reliable and non-invasive alternative, but it has never been discussed in children in whom vertebral artery dissection is a rare condition. In this report, we evaluate a case of a 2-year-old child who initially presented with cerebellar symptoms, and was early diagnosed with vertebral artery dissection using HR- MRI and was successfully treated.

• Journal of Korean Neurosurgical Society
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• 제66권4호
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• pp.446-455
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• 2023

Objective : Chronic subdural hematoma (CSDH) is a common neurosurgical disease and generally treated with burr-hole surgery alone. Tranexamic acid (TXA) is an antifibrinolytic agent that potentially reduces recurrence rates and the residual hematoma volume. However, the role of postoperative TXA medication remains unclear to date. This study aimed to verify the effectiveness of adjunctive TXA in the view of early hematoma resolution. Methods : Between January 2018 and September 2021, patients with CSDH who underwent burr-hole trephination in a single tertiary institute were reviewed. The study population was divided into three groups, TXA, non-TXA, and antithrombotics (AT) groups, according to the medical history of cardio-cerebrovascular disease and TXA administration. The primary endpoint was CSDH recurrence, defined as re-appearance or re-accumulation of CSDH requiring neurosurgical interventions. The secondary outcome was CSDH resolution, defined as complete or near-complete resorption of the CSDH. The CSDH resolution time and serial changes of hematoma thickness were also investigated. Results : A total of 240 patients was included in the analysis consisting of 185 male and 55 female, with a median age of 74 years. During the median imaging follow-up period of 75 days, 222 patients were reached to the primary or secondary endpoint. TXA was administered as an adjunctive therapy in 41 patients (TXA group, 16.9%) while 114 patients were included in the non-TXA group (47.9%) and 85 were in the AT group. The recurrence rate was the lowest in the TXA group (2.4%), followed by non-TXA (7.0%) and AT (8.2%) groups. However, there was no statistical significance due to the small number of patients with recurrence. CSDH resolution was achieved in 206 patients, and the median estimated time to resolution was significantly faster in the TXA group (p<0.001). Adjunctive TXA administration was a significant positive factor for achieving CSDH resolution (p<0.001). The hematoma thickness was comparable among the three groups at the initial time and after surgery. However, CSDH thickness in the TXA group decreased abruptly in a month and showed a significant difference from that in the other groups (p<0.001). There was no TXA-related adverse event. Conclusion : The adjunctive use of TXA after CSDH surgery significantly facilitated the resorption of residual CSDH and resulted in the early CSDH resolution. Adjunctive TXA may be an effective treatment option to reduce recurrence by enhancing CSDH resolution in the selective patients.

• Childhood Kidney Diseases
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• 제11권1호
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• pp.74-82
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• 2007

목적 : 소아의 일차성 방광요관역류는 요로감염과 이로 인한 신손상의 위험성이 높지만 방광이 성장함에 따라 자연 소실되거나 호전되는 경향이 있다. 본 연구에서는 일차성 방광요관역류의 임상적 특성과 자연소실율 및 그와 관련된 인자들을 분석하고자 하였다. 방법 : 1991년 10월부터 2003년 7월까지 본원 소아과에서 일차성 방광요관 역류로 진단되어 예방적 저용량 항생제 치료를 받았던 총 149명 소아를 대상으로 후향적으로 의무기록을 조사하였다. 대상 환아들은 12-18개월마다 동위원소 방광요도 조영술을 실시하여 역류가 소실되지 않은 경우 3년 이상 추적 검사하였다. 결과 : 대상 환아 149명 중 남아는 73.2%로 여아보다 많았고, 1세 미만은 69.1%로 이 중 남아가 86.4%로 대부분이었다. 역류의 진단 당시 평균 연령은 $16.1{\pm}21.1$개월이었고, 임상 양상으로는 요로 감염이 91.3%로 가장 많았다. 역류의 자연 소실 median time은 24개월이었고, 총 3년 누적소실율은 61.7%였다. 역류의 자연 소실과 관련된 인자들 중 남아, 1세 미만 영아, 낮은 역류의 등급, 일측성 역류, 산전 초음파상 수신증이 있어 역류가 진단된 경우, 형제간에 역류의 가족력이 없었던 경우, 진단당시 신 스캔상 신피질 결손이 없었던 경우, 추적 검사상 요로감염 재발 및 신손상이 없었던 경우의 자연 소실율이 더 높았다. 단변량 분석과 다변량 분석을 이용하여 역류의 자연소실과 독립적으로 관련된 유의한 인자들로는 1세 미만 영아 relative risk 1.77(P<0.05), 낮은 역류 등급(I+II) 2.98(P<0.05), 추적 중 신반흔 형성이 없는 군2.23(P<0.05), 신위축이 없는 군 5.20(P<0.01)이었다. 결론 : 본 연구결과 소아의 일차성 방광 요관 역류는 높은 자연 소실율을 보였으며, 특히 영아기에 진단된 경우 IV 등급 이상의 높은 등급에서도 자연 소실율이 높아 조기의 수술적 치료는 피하고 약물요법을 지속하는 것이 바람직하다. 또한 역류의 자연 소실은 진단 당시 연령, 역류의 등급과 추적 검사상 신반흔 및 신위축의 유무와 관련이 있을 것으로 사료된다.

• 한국환경보건학회지
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• 제33권4호
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• pp.306-316
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• 2007

This study have a object to found out the effects of oriental herb medicine, Antaeeum, to dams of rats and their offsprings. The Antaeeum was savaged to female Sprague-Dawley rats at a dose of 5 mg/kg/day for 3 weeks during gestation periods. Dams of rat were sacrificed at 20th day of gestation, and were observed major internal and reproductive organs. Approximately live fetuses in the 20th days of gestation were selected randomly and examined with stereo microscopes. Others offsprings were fixed with 95% ethanol for skeletal examinations. The fixed fetuses were stained with alcian blue and alizarin red S to observe skeletal variations or malformations. Maternal body weight of Antaeeum treated dams have a tendency of increasing compared with control dams. There were no significant difference in internal and reproductive organs of weight or findings. The spleenic organ relative weight of treated dams were decreased compared with the control significaltly (p<0.05). There were no significant changes between two groups in blood chemistry and hematological values. There were no significant changes in number of corpus luteum, implantation, live fetuses and implantation rate, delivery rate, late resorption rate and sex ratio. But in the Antaeeum treated group showed lower early resorption rate than that of the control dams. Fetal body weight and number of fetus a dam at Antaeeum treated group were higher than that of control group. The fetuses of dams treated with Antaeeum didn't induced external malformations. Vertebral and sternal variations were observed in Antaeeum group, but compared with the control, those variations were not significant. The ossification numbers of rib, cervical, thoracic, and lumber were normal. Fetuses treated with Antaeeum to the dams showed no significant difference in the number of caudal vertebra (P>0.01). From these results, it can be concluded that Antaeeum showed no toxicity effects on maternal side especially on body weight, early resorption rate, and number of live fetuses. Also there were no significant changes on maternal organ weights except spleen, hematological data, reproductive organs. Although skeletal variations were examined at vertebra and sternum, this Antaeeum could not induced significant choses in bone malformation.

• 한국통신학회논문지
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• 제29권1B호
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• pp.29-40
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• 2004

본 논문에서는 TCP 흐름제어 기법을 전제로 하여, 가까운 미래에 발생할 가능성이 있는 인터넷 입구에서의 혼잡을 미리 예측함으로써 TCP 흐름제어의 효과를 배가시킬 수 있는 QR-AQM이라는 버퍼관리 기법을 제안한다. QR-AQM 버퍼관리기법은 라우터로 전송되어 오는 단위시간당 TCP 흐름량을 추정하여 이를 이용함으로써 RED기법과 같이 평균버퍼 수위에만 의존하는 조기혼잡제어기법에 비해 미래에 네트워크에 일어날 혼잡에 보다 민첩하게 대처 할 수 있다. 모의 실험을 통한 성능 검증결과 인터넷 입구에서 OR-AQM 기법은 Adaptive RED 기법과 비교하여 간단한 변수의 설정만으로 버퍼를 목적한 수준으로 유지함이 가능함으로, 다양한 응용프로그램의 요구에 맞추어 직관적이고 쉽게 최적의 버퍼수위를 설정할 수 있다. 또한 QR-AQM 기법은 시간에 따른 버퍼수위의 변화가 목적한 버퍼수위를 기준으로 작은 변동폭을 유지함으로써, 패킷들이 라우터의 버퍼를 지나면서 겪게되는 지연시간의 등락현상을 효과적으로 억제할 수 있음을 확인하였다.

• ETRI Journal
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• 제36권3호
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• pp.407-417
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• 2014

A new-generation video coding standard, named High Efficiency Video Coding (HEVC), has recently been developed by JCT-VC. This new standard provides a significant improvement in picture quality, especially for high-resolution videos. However, one the most important challenges in HEVC is time complexity. A quadtree-based structure is created for the encoding and decoding processes and the rate-distortion (RD) cost is calculated for all possible dimensions of coding units in the quadtree. This provides a high encoding quality, but also causes computational complexity. We focus on a reduction scheme of the computational complexity and propose a new approach that can terminate the quadtree-based structure early, based on the RD costs of the parent and current levels. Our proposed algorithm is compared with HEVC Test Model version 10.0 software and a previously proposed algorithm. Experimental results show that our algorithm provides a significant time reduction for encoding, with only a small loss in video quality.

• 한국방사선학회논문지
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• 제15권2호
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• pp.153-158
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• 2021

치주질환의 조기 진단률 및 예측 정확도 향상을 위한 X-선 영상 분석은 매우 중요한 분야이다. 이러한 치과 X-선 영상의 화질 개선을 위한 인공 지능 기반의 알고리즘 개발 및 적용에 관한 연구는 전 세계적으로 널리 수행 중이다. 따라서 본 연구의 목표는 치주질환 예측을 위한 치과 X-선 영상에서의 초해상화 알고리즘의 모델링 및 적용 가능성에 관하여 평가하는 것이다. 초해상화 알고리즘은 convolution layer와 ReLU를 기반으로 구성하였고, 저해상도 영상을 2배로 업샘플링 한 영상을 입력으로 사용하였다. 딥러닝 훈련을 위해 사용한 치과 X-선 데이터는 1,500장을 사용하였다. 영상의 정량적 평가는 2가지 영상의 비교를 통해 유사도를 측정할 수 있는 인자인 root mean square error와 structural similarity를 사용하였다. 이와 더불어 최근에 개발된 no-reference 기반으로 사용되는 natural image quality evaluator 와 blind/referenceless image spatial quality evaluator를 추가적으로 분석하였다. 결과적으로 기존에 사용되던 bicubic 기반의 업샘플링 기법을 사용하였을 때에 비하여 제안하는 방법이 치과 X-선 영상에서 평균적으로 유사도와 no-reference 기반의 평가 인자가 각각 1.86 그리고 2.14배 향상됨을 확인하였다. 결론적으로 치주질환의 예측을 위한 초해상화 알고리즘의 치과 X-선 영상에서의 유용성을 증명하였고 향후 다양한 분야에서의 적용 가능성이 높을 것으로 기대된다.