• Journal of Acupuncture Research
• /
• 제20권2호
• /
• pp.123-134
• /
• 2003

Objective : This experimental in vitro study investigates the effects of electro acupuncture stimuli to the DCX and PSA-NCAM positive cells in the dentate gyrus of spontaneously hypertensive rats. Methods : We used immunohistochemical methods to observe the change of neuron cells, and then counts the immunoactive cells under the $100{\times}$ visual field optical microscope. Results : 1. The counts of DCX-positive cells in the dentate gyrus significantly increased in the 2Hz group versus control group. Otherwise 100Hz group did not have a significant differance. 2. The counts of PSA-NCAM-positive cells in the dentate gyrus rather decreased in the both 2Hz group and 100Hz group versus control group. Conclusions : We find out the electro acupuncture stimuli have some effects upon cerebral neuron cell in the dentate gyrus spontaneously hypertensive rats.

• 한국신뢰성학회:학술대회논문집
• /
• 한국신뢰성학회 2000년도 추계학술대회
• /
• pp.269-277
• /
• 2000

The component reliability database is required in PSA (Probabilistic Safety Analysis) for NPP (Nuclear Power Plant). We have applied a generic database to the PSA for the Korean NPPs, since there is no specific component reliability database. Therefore we are developing the plant-specific component reliability database for domestic NPPs. We also extend the experience and knowledge of PSA and component reliability database for NPP to chemical industry We collect the raw data like component operation history and maintenance history and then input the required data for the component reliability database through failure analysis. With the database, we can not only perform PSA with real data but also perform maintenance optimization.

• 대한세포병리학회지
• /
• 제15권2호
• /
• pp.81-85
• /
• 2004

Postmenopausal squamous atypia (PSA) is a phenomenon characterized by cellular alterations mimicking condyloma in the uterine cervix of postmenopausal women. It is not associated with human papillomavirus (HPV) infection. The aim of this study is to correlate findings with HPV infection and the cytohistologic findings of PSA. Eighty-three smears from postmenopausal women, initially interpreted as ASCUS and low-grade squamous intraepithelial lesions(LSIL), were reviewed according to the criteria of PSA. Fifty-eight cases were subsequently reclassified as PSA. Forty cases categorized as PSA were available for HPV-DNA detection by a nested polymerase chain reaction. Eight of these 40 cases(20%) showed biopsy-proven LSIL lesions. The HPV-DNA was detected in 42.5%(17/40), compared to 25%(5/20) of control cases. The HPV-DNA detection rate of biopsy-proven LSIL was 62.5%(5/8). It has been concluded that cytologic differential diagnosis of PSA from LSIL is difficult due to because of poor histologic and viral correlation.

• Nuclear Engineering and Technology
• /
• 제55권12호
• /
• pp.4367-4381
• /
• 2023

Nuclear power plants are increasingly being equipped with digital I&C systems. Although some probabilistic safety assessment (PSA) models for the digital I&C of nuclear power plants have been constructed, there is currently no specific internationally agreed guidance for their modeling. This paper presents an initiative by the OECD Nuclear Energy Agency called "Digital I&C PSA - Comparative application of DIGital I&C Modelling Approaches for PSA (DIGMAP)", which aimed to advance the field towards practical and defendable modeling principles. The task, carried out in 2017-2021, used a simplified description of a plant focusing on the digital I&C systems important to safety, for which the participating organizations independently developed their own PSA models. Through comparison of the PSA models, sensitivity analyses as well as observations throughout the whole activity, both qualitative and quantitative lessons were learned. These include insights on failure behavior of digital I&C systems, experience from models with different levels of abstraction, benefits from benchmarking as well as major contributors to the core damage frequency and those with minor effect. The study also highlighted the challenges with modeling of large common cause component groups and the difficulties associated with estimation of key software and common cause failure parameters.

• Nuclear Engineering and Technology
• /
• 제53권2호
• /
• pp.386-392
• /
• 2021

MACCS (MELCOR Accident Consequence Code System), WinMACCS, and MelMACCS now facilitate a multi-unit consequence analysis. MACCS evaluates the consequences of an atmospheric release of radioactive gases and aerosols into the atmosphere and is most commonly used to perform probabilistic safety assessments (PSAs) and related consequence analyses for nuclear power plants (NPPs). WinMACCS is a user-friendly preprocessor for MACCS. MelMACCS extracts source-term information from a MELCOR plot file. The current development can combine an arbitrary number of source terms, representing simultaneous releases from a multi-unit facility, into a single consequence analysis. The development supports different release signatures, fission product inventories, and accident initiation times for each unit. The treatment is completely general except that the model is currently limited to collocated units. A major practical consideration for performing a multi-unit PSA is that a comprehensive treatment for more than two units may involve an intractable number of combinations of source terms. This paper proposes and evaluates an approach for reducing the number of calculations to be tractable, even for sites with eight or ten units. The approximation error introduced by the approach is acceptable and is considerably less than other errors and uncertainties inherent in a Level 3 PSA.

• Nuclear Engineering and Technology
• /
• 제53권4호
• /
• pp.1127-1133
• /
• 2021

A Spent Fuel Pool (SFP) is designed to store spent fuel assemblies in the pool. And, a SFP cooling and cleanup system cools the SFP coolant through a heat exchanger which exchanges heat with component cooling water. If the cooling system fails or interfacing pipe (e.g., suction or discharge pipe) breaks, the cooling function may be lost, probably leading to fuel damage. In order to prevent such an incident, it is required to properly cool the spent fuel assemblies in the SFP by either recovering the cooling system or injecting water into the SFP. Probabilistic safety assessment (PSA) is a good tool to assess the SFP risk when an initiating event for the SFP occurs. Since PSA has been focused on reactor-side so far, it is required to study on the framework of PSA approach for SFP and identify the key factors in terms of fuel damage frequency (FDF) through a case study. In this study, therefore, a case study of SFP-PSA on the basis of design information of APR-1400 has been conducted quantitatively, and several sensitivity analyses have been conducted to understand the impact of the key factors on FDF.

• Nuclear Engineering and Technology
• /
• 제50권8호
• /
• pp.1217-1233
• /
• 2018

Following a surge of interest in multi-unit risk in the last few years, many recent studies have suggested methods for multi-unit probabilistic safety assessment (MUPSA) and addressed several related aspects. Most of the existing studies though focused on two-unit nuclear power plant (NPP) sites or used rather simplified probabilistic safety assessment (PSA) models to demonstrate the proposed approaches. When considering an NPP site with three or more units, some approaches are inapplicable or yield very conservative results. Since the number of such sites is increasing, there is a strong need to develop and validate practical approaches to the related MUPSA. This article provides several detailed approaches that are applicable to multi-unit Level 1 PSA for sites with up to six or more reactor units. To validate the approaches, a multi-unit Level 1 PSA model is developed and the site core damage frequency is estimated for each of four representative multi-unit initiators, as well as for the case of a simultaneous occurrence of independent single-unit initiators in multiple units. For this purpose, an NPP site with six identical OPR-1000 units is considered, with full-scale Level 1 PSA models for a specific OPR-1000 plant used as the base single-unit models.

• 한국전산구조공학회논문집
• /
• 제31권1호
• /
• pp.31-38
• /
• 2018

설계기준을 초과하는 지진 재해는 원자력 시설물에 상당한 위험을 유발할 수 있다. 이러한 위험성을 확률론적으로 정량화하는 방법이 확률론적 지진 안전성 평가(seismic probabilistic safety assessment)이다. 이에 따라 지진 PSA는 국내외 다수의 원자력 발전소에 적용되어 지진 재해에 대한 원전의 안전성을 확률론적으로 평가하고 이에 대비토록 하고 있다. 그러나 원전에 비해 상대적으로 규모가 작은 연구용 원자로와 같은 경우에는 지진 PSA가 적용된 예가 거의 없다. 따라서, 본 연구에서는 지진 PSA기법을 실제 완공된 연구로에 적용하여 안전성을 분석하였다. 또한, 이를 바탕으로 연구로를 구성하는 시스템의 지진 내력에 대한 최적화 연구를 수행하였다. 그 결과, 지진 재해 하에서 연구로에 발생할 수 있는 노심 손상 가능성을 정량화하였고, 현재 설계안과 비교하여 적은 비용으로 최대의 안전성을 확보하는 최적 지진 내력 분포를 도출하였다. 이러한 결과는 향후 지진에 대비하여 연구로 안전성을 효과적으로 제고할 수 있는 정량적 지표로 활용할 수 있을 것으로 판단된다.

• Asian Pacific Journal of Cancer Prevention
• /
• 제15권10호
• /
• pp.4175-4179
• /
• 2014

Aims: To delineate the histopathological pattern of prostate diseases and to highlight age variations in prostate specific antigen (PSA) values and histopathological features. Materials and Methods: A retrospective review was made of all prostate biopsy reports seen between January 2006 and December 2013 at the King Fahad Hospital, Madinah, Saudi Arabia. Prostate lesions were tabulated and classified into benign and malignant groups. Histological scoring of adenocarcinomas was accomplished using the Gleason system. PSA values were correlated with Gleason scores. Results: Of 417 prostate lesions reviewed, 343 (82.3%) were benign and 74 (17.7%) were malignant, giving a benign to malignant ratio of 4.6:1. Benign prostatic hyperplasia (both with and without inflammation) was the commonest prostatic lesion and accounted for 80.3% of all cases and 97.6% of all benign cases. The age range was 20 to 97 years with a mean of 69.2 years and a peak age group at 70-79 years. Seventy one cases of adenocarcinoma accounted for 95.9% of the total of 74 malignant tumors. It showed an age range of 44 to 95 years, a mean age of 70.9 years and peak prevalence in the 80-89 year age group. Gleason score seven was the most frequent (39.4%) in occurrence. Most adenocarcinomas, 41 cases (57.7%), were moderately differentiated (Gleason score of 5-7). PSA values ranged widely between 16-1,865ng/ml with a mean of 363.4ng/ml. Elevated PSA (>100ng/ml) levels were found in 53 (81.6%) patients. There was a statistically significant positive correlation between serum PSA level and Gleason score (p=0.0304). Conclusions: Prostatic lesions constitute a significant source of morbidity among adult males in Madinah. Benign prostatic hyperplasia was the commonest benign prostatic lesion and adenocarcinoma was the commonest histological subtype of prostatic cancer.

• 한국버섯학회지
• /
• 제13권3호
• /
• pp.181-184
• /
• 2015

버섯은 영양소 및 풍미가 뛰어나 오래전부터 식재료로 널리 활용되고 있으며 항염증 및 항산화효능도 뛰어난 것으로 알려져 있다. 그러나 버섯의 항산화 효능은 아직 연구가 미비한 실정이다. 따라서 본 연구에서는 버섯의 항전립선암 효능을 분석하였다. 이를 위해, 식용버섯인 참송이버섯, 꽃송이버섯, 편각영지버섯, 녹각영지, 현미동충하초버섯, 잎새버섯, 석이버섯, 상황버섯 등 8종 버섯의 열수 추출물에 대한 항전립선암 효능을 전립선암 세포주인 LNCaP에서 확인한 결과 참송이버섯, 편각영지버섯 및 현미동충하초버섯이 PSA 발현을 저해하는 효능이 탁월한 것을 확인하였다.