• Asian Pacific Journal of Cancer Prevention
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• 제14권4호
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• pp.2627-2630
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• 2013

Background: Ovarian cancer continues to pose a major challenge to physicians and radiologists. It is the third most common gynecologic malignancy and estimated to be fifth leading cancer cause of death in women, constituting 23% of all gynecological malignancies. Multi-detector computed tomography (MDCT) appears to offer an excellent modality in diagnosing ovarian cancer based on combination of its availability, meticulous technique, efficacy and familiarity of radiologists and physicians. The aim of this study was to compute sensitivity, specificity, positive and negative predictive values and diagnostic accuracy of 64-slice MDCT in classifying ovarian masses; 95% confidence intervals were reported. Materials and Methods: We prospectively designed a cross-sectional analytical study to collect data from July 2010 to August 2011 from a tertiary care hospital in Karachi, Pakistan. A sample of 105 women aged between 15-80 years referred for 64-MDCT of abdomen and pelvis with clinical suspicion of malignant ovarian cancer, irrespective of stage of disease, were enrolled by non-probability purposive sampling. All patients who were already known cases of histologically proven ovarian carcinoma and having some contraindication to radiation or iodinated contrast media were excluded. Results: Our prospective study reports sensitivity, specificity; positive and negative predictive values with 95%CI and accuracy were computed. Kappa was calculated to report agreement among the two radiologists. For reader A, MDCT was found to have 92% (0.83, 0.97) sensitivity and 86.7% (0.68, 0.96) specificity, while PPV and NPV were 94.5% (0.86, 0.98) and 86.7% (0.63, 0.92), respectively. Accuracy reported by reader A was 90.5%. For reader B, sensitivity, specificity, PPV and NPV were 94.6% (0.86, 0.98) 90% (0.72, 0.97) 96% (0.88, 0.99) and 87.1% (0.69, 0.95) respectively. Accuracy computed by reader B was 93.3%. Excellent agreement was found between the two radiologists with a significant kappa value of 0.887. Conclusion: Based on our study results, we conclude MDCT is a reliable imaging modality in diagnosis of ovarian masses accurately with insignificant interobserver variability.

• 응용통계연구
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• 제24권1호
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• pp.115-125
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• 2011

사망률 예측모형과 생명표 작성방법에 기반을 둔 예측평균수명 작성은 미래의 사망수준을 평가하는 효과적인 방법이 된다. 2006년 통계청에서 장래인구추계 작성 시 예측평균수명을 작성하였으나, 2006년 이후 현재까지 실제평균수명과 적지 않은 차이를 보이고 있어 평균수명의 증가속도를 반영하지 못하고 있다. 이의 원인으로는 전망치에 대한판단, 사망률 예측모형의 선택과 사용 등이 이유가 될 수 있다. 본 논문에서는 사망률 예측모형의 선택관점에서 이 문제를 살펴보고자 한다. 2011년 장래인구추계 작성을 앞둔 상황에서 오류의 반복을 피하기 위해서는 사망률 예측모형에 대한 특성 및 적용가능성에 대한 충분한 검토가 이루어진 후 적절한 모형을 선택해야 할 것이다. 사망률 예측모형은 주로 사용되고 있는 LC(Lee와 Carter) 모형과 이의 개선모형들, 사망확률 확장모형인 HP8(Heligman과 Pollard 8 parameters) 모형 등 모두 5개의 모형을 비교 분석하였다. 분석결과를 바탕으로 5개의 모형별로 2030까지의 남녀별 예측평균수명을 작성하여 제시하였고, 이를 통계청에서 제공하는 예측평균수명과 비교하였다. 5개의 모형에 의해 작성된 2030년까지의 새로운 예측평균수명은 통계청의 결과보다 높게 나타나 실제평균수명의 변화를 상대적으로 잘 반영하는 것으로 나타났다.

• The Korean Journal of Physiology and Pharmacology
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• 제17권1호
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• pp.57-64
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• 2013

Cells can resist and even recover from stress induced by acute hypoxia, whereas chronic hypoxia often leads to irreversible damage and eventually death. Although little is known about the response(s) to acute hypoxia in neuronal cells, alterations in ion channel activity could be preferential. This study aimed to elucidate which channel type is involved in the response to acute hypoxia in rat pheochromocytomal (PC12) cells as a neuronal cell model. Using perfusing solution saturated with 95% $N_2$ and 5% $CO_2$, induction of cell hypoxia was confirmed based on increased intracellular $Ca^{2+}$ with diminished oxygen content in the perfusate. During acute hypoxia, one channel type with a conductance of about 30 pS (2.5 pA at -80 mV) was activated within the first 2~3 min following onset of hypoxia and was long-lived for more than 300 ms with high open probability ($P_o$, up to 0.8). This channel was permeable to $Na^+$ ions, but not to $K^+$, $Ca^+$, and $Cl^-$ ions, and was sensitively blocked by amiloride (200 nM). These characteristics and behaviors were quite similar to those of epithelial sodium channel (ENaC). RT-PCR and Western blot analyses confirmed that ENaC channel was endogenously expressed in PC12 cells. Taken together, a 30-pS ENaC-like channel was activated in response to acute hypoxia in PC12 cells. This is the first evidence of an acute hypoxia-activated $Na^+$ channel that can contribute to depolarization of the cell.

• 한국통신학회논문지
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• 제18권1호
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• pp.110-122
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• 1993

음성이 패킷망을 통해 전송될때 각각의 call들에 의해서 발생되는 패킷들은 statistical multiplexer에 의해 다중화 되는데 이때 overload control이 필요하다. Overload control 방식은 음성 traffic을 coding하는 방식과 밀접한 관계가 있으며 그동안 많은 연구가 진행되어 왔다. CCITT에서는 최근에 packetized voice protocol에 대한 권고안 초안인 G.764를 작성하였는데 여기에서 embedded coding을 사용하는 경우에 bit dropping 방식을 사용하면 매우 훌륭하게 overload control을 할 수 있다는 사실을 언급하였다. 이에 따라 본 논문에서는 음성을 embedded ADPCM으로 coding하여 CCITT권고안 G.764에 따라 전송하는 경우에, bit dropping 방식에 따른 overload control 방식을 사용하는 패킷 multiplexer의 성능을 분석하고자 한다. 성능 분석을 위해서는 먼저 multiplexer에 도착하는 중첩된 packet arrival process에서 패킷들의 interarrival time들 간에 존재하는 큰 correlation을 정확히 나타낼 수 있는 수학적인 model이 필요하다. 본 논문에서는 Poisson process나 birth-and-death process에 비해 이들 packet arrival process를 상대적으로 정확히 표현할 수 있는 Makov-modulated Poisson Process(MMPP)를 사용하여 모델링을 하였다.따라서 성능분석은 MMPP/G/1 queueing system에 대한 분석과 비슷하다. 다만 서비스 시간의 분포가 시스템의 상태에 따라 달라지는데 이러한 경우에 대해서는 기존의 논문에서 분석되지 않았다. 성능분석을 통하여 queue에서 서비스를 기다리는 패킷의 수에 대한 분포의 Z-transform을 구하고 이를 이용하여 임의의 시간에서의 queue length와 waiting time의 평균과 표준편차를 구하였다. 이를 통하여 bit dropping 방식에 의한 overload control이 음성의 질을 많이 저하시키지 않으면서도 overload control을 하지 않을 때에 비해 statistical multiplexer에서 훨씬 많은 수의 call을 수용할 수 있도록 하는 효과를 가진다는 사실을 확인 하였다. 또한 패킷이 queue에서 떠난 직후와 임의의 시간에서 구한 queue length와 waiting time의 평균과 표준편차가 매우 비슷하다는 사실을 알 수 있었다. 본 논문에서와 마찬가지로 임의의 시간에서의 분석은 매우 복잡한 경우가 대부분이므로 이러한 사실을 이용하면 매우 간단히 성능분석을 할 수 있을 것이다.

• Radiation Oncology Journal
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• 제37권3호
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• pp.176-184
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• 2019

Purpose: It is unclear whether adding concurrent chemotherapy (CT) to definitive radiotherapy (RT) following induction CT is a tolerable and cost effective treatment for non-small-cell lung cancer (NSCLC) patients aged 70 years or older with comorbidities. This study evaluated the actual clinical outcomes between concurrent chemoradiotherapy (CCRT) and RT alone following induction CT or not in patients (≥70 years) in a single institution's clinical practice. Materials and Methods: A total of 82 patients with unresectable stage III NSCLC between 2004 and 2016 were retrospectively analyzed. Their treatment tolerance and clinical outcomes such as overall survival (OS), locoregional recurrence (LRR), treatment toxicities and distant metastasis (DM) were evaluated. Early mortality rates were also evaluated as 4-month mortality after RT. Results: Fifty-four patients received CCRT and 28 patients received RT alone. Induction CT before RT was performed for 68.5% and 50.0% in CCRT and RT alone groups. Treatment tolerance was significantly worse in CCRT (p = 0.046). The median survival was 21.1 and 18.1 months for CCRT and RT alone, which was not statistically significant. LRR and DM were also not different. Most early deaths after CCRT were attributed to non-cancer-related mortality. Acute esophagitis of grade ≥2 occurred more following CCRT (p = 0.017). In multivariate analysis, a Charlson Comorbidity Index (CCI) of ≥5 and a weight loss of ≥5% after RT were associated with poor OS. The factors adversely affecting 4-month survival were a CCI of ≥5 and CCRT. Conclusion: There were no significant differences in OS, LRR, and DM between CCRT and RT alone treatment in elderly patients. However, there was a poorer tolerance and higher incidence of acute esophagitis in the CCRT group. Specifically, when the patients had a CCI of ≥5, RT alone seems to be reasonable with a low probability of early death.

• 대한의용생체공학회:의공학회지
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• 제18권4호
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• pp.429-438
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• 1997

기계식 판막은 매몰식 인공장기에 널리 사용돼 왔으며, 판막의 이상은 환자의 죽음으르 의미한다. 판막의 이상에 영향을 미치는 것은 많은 요소들이 있는데 대표적으로 기계적인 고장과 혈전현상이 있다. 그래서 비침습적으로 이것들을 발견하는 것이 필요하게 된 것이다. 이 논문의 목적은 스펙트럼의 해석과 인공신경망을 이용하여 혈전현상을 발견하는데 있다. 신호의 측정은 공압식 좌심실 보조장치에 장착한 기계식 판막으로부터 마이크로폰과 증폭기를 이용하였다. 디스크 위의 모의 혈전현상과 봉합링의 주위에 혈전현상, 20%, 40% 60%로 자라나는 혈전현상은 펠레세인과 실리콘을 이용하여 제작하였다. 기초 성능 평가를 위해 1KHz 정현파를 인가하여 시스템을 평가하였으며, 정상적인 판막과 5 종류의 혈전현상의 스펙트럼은 혈전현상의 정보를 지닌 개폐시 peak의 신호 파형에서 구하였다. 데이터의 정량적인 해석을 위해 7,000개의 입력 노드와 20개의 은닉층과 1개의 출력층으로 이루어진 인공신경망을 사용하였다. 결론적으로 훈련된 인공신경망을 사용한 결과 정상 판막과 비정상 판막을 판단하는데 90%의 판단능력을 보였다. 이상의 실험을 통해 판막의 이상유무를 신호의 스펙트럼 해석과 인공신경망을 통해 평가할수 있음을 알 수 있었다. 본 논문의 결과는 앞으로 인공장기를 몸속에 지니고 있는 환자에게서 장기의 상태를 지속적으로 감시할 수 있는 기술적 토대를 제공할 것이다.

• Radiation Oncology Journal
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• 제38권2호
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• pp.99-108
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• 2020

Purpose: The probability of recurrence of cancer after adjuvant or definitive radiotherapy in patients with human papillomavirus-negative (HPV(-)) head and neck squamous cell carcinoma (HNSCC) varies for each patient. This study aimed to identify and validate radiation sensitivity signature (RSS) of patients with HPV(-) HNSCC to predict the recurrence of cancer after radiotherapy. Materials and Methods: Clonogenic survival assays were performed to assess radiosensitivity in 14 HNSCC cell lines. We identified genes closely correlated with radiosensitivity and validated them in The Cancer Genome Atlas (TCGA) cohort. The validated RSS were analyzed by ingenuity pathway analysis (IPA) to identify canonical pathways, upstream regulators, diseases and functions, and gene networks related to radiosensitive genes in HPV(-) HNSCC. Results: The survival fraction of 14 HNSCC cell lines after exposure to 2 Gy of radiation ranged from 48% to 72%. Six genes were positively correlated and 35 genes were negatively correlated with radioresistance, respectively. RSS was validated in the HPV(-) TCGA HNSCC cohort (n = 203), and recurrence-free survival (RFS) rate was found to be significantly lower in the radioresistant group than in the radiosensitive group (p = 0.035). Cell death and survival, cell-to-cell signaling, and cellular movement were significantly enriched in RSS, and RSSs were highly correlated with each other. Conclusion: We derived a HPV(-) HNSCC-specific RSS and validated it in an independent cohort. The outcome of adjuvant or definitive radiotherapy in HPV(-) patients with HNSCC can be predicted by analyzing their RSS, which might help in establishing a personalized therapeutic plan.

• 비교문화연구
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• 제39권
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• pp.241-286
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• 2015

This study explores how folktales' motifs are used in diverse cultural contents such as literature, movies, or comics. More precisely, it is concerned with mysterious characters like Babayaga and Koshchei who appear in Russian fairytales. When the motifs of the reviewed literature are analyzed, the following three criteria are used for classification: New Writing, Rewriting, and New Version. Or course, it is New Writing that is far from the original work. Most of the collected works, including Joan Aiken's The Kingdom Under the Sea, Patricia Polacco's Babushka's Doll, Babushka Baba Yaga, and Tai?-Marc Le Thanh's BABAYAGA, belong to New Writing. The New Writing type mainly focuses on Babayaga's secluded life. In fairytales, Babayaga is depicted as the goddess of Mother Earth, the heroine of the Nature, or the ruler of the Animal Kingdom. That is why she lives in the deep and uninhabited wood. She is related to the Coming of Age ceremony. Her 'Hut on hen's legs' is an obstacle for immature protagonists to face before they come of age. Protagonists are supposed to solve the problems posed by Babayaga. If they succeed, they can get her magical help so as to complete their final mission. Babayaga is likely to appear as their antagonist. Protagonist may be subjected to a terrible ordeal created by Babayaga, and then come of age by recovering from that ordeal. Sometimes, Babayaga helps protagonists to get a grip on reality. That is why she lives in a hut in the deep and dark forest which is on the borderline between life and death. On the other hand, Marianna Mayer's Baba Yaga and Vasilisa the Brave has been classified as a controversial work between New Writing and Rewriting. It is apparently closer to New Version. However, it cannot be classified as a work of New Version because the author incorporates 'probability' into her work. Among the reviewed works, it is Korean Writer Rye, Kami's The Spider Woman's House that best reflects the essence of Babayaga. Babayaga and other characters are amusing in movies because most of the movies are animations for children. In one sense, it is positive that the scary characters in folktales are approachable to children. In other sense, however, it is regrettable that symbolic motifs are completely eliminated. In Mike Mignola's Hellboy, Japanese animations such as Index or Narutaru, on-line games such as Cabal or Vampire: The masquerade, the essence of the supernatural characters in folktales is completely eliminated, and only their 'belligerent power' stands out. It is desirable to put stories into perspective whether they are written or told. The literature property of folktales provides a special opportunity to readers. In this light, a variety of motifs have a good reason to be reborn as modern cultural contents. The bottom line is to maintain its true nature.

• Journal of Korean Neurosurgical Society
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• 제64권5호
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• pp.791-798
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• 2021

Objective : The period of mechanical ventilator (MV)-dependent respiratory failure after cervical spinal cord injury (CSCI) varies from patient to patient. This study aimed to identify predictors of MV at hospital discharge (MVDC) due to prolonged respiratory failure among patients with MV after CSCI. Methods : Two hundred forty-three patients with CSCI were admitted to our institution between May 2006 and April 2018. Their medical records and radiographic data were retrospectively reviewed. Level and completeness of injury were defined according to the American Spinal Injury Association (ASIA) standards. Respiratory failure was defined as the requirement for definitive airway and assistance of MV. We also evaluated magnetic resonance imaging characteristics of the cervical spine. These characteristics included : maximum canal compromise (MCC); intramedullary hematoma or cord transection; and integrity of the disco-ligamentous complex for assessment of the Subaxial Cervical Spine Injury Classification (SLIC) scoring. The inclusion criteria were patients with CSCI who underwent decompression surgery within 48 hours after trauma with respiratory failure during hospital stay. Patients with Glasgow coma scale 12 or lower, major fatal trauma of vital organs, or stroke caused by vertebral artery injury were excluded from the study. Results : Out of 243 patients with CSCI, 30 required MV during their hospital stay, and 27 met the inclusion criteria. Among them, 48.1% (13/27) of patients had MVDC with greater than 30 days MV or death caused by aspiration pneumonia. In total, 51.9% (14/27) of patients could be weaned from MV during 30 days or less of hospital stay (MV days : MVDC 38.23±20.79 vs. MV weaning, 13.57±8.40; p<0.001). Vital signs at hospital arrival, smoking, the American Society of Anesthesiologists classification, Associated injury with Injury Severity Score, SLIC score, and length of cord edema did not differ between the MVDC and MV weaning groups. The ASIA impairment scale, level of injury within C3 to C6, and MCC significantly affected MVDC. The MCC significantly correlated with MVDC, and the optimal cutoff value was 51.40%, with 76.9% sensitivity and 78.6% specificity. In multivariate logistic regression analysis, MCC >51.4% was a significant risk factor for MVDC (odds ratio, 7.574; p=0.039). Conclusion : As a method of predicting which patients would be able to undergo weaning from MV early, the MCC is a valid factor. If the MCC exceeds 51.4%, prognosis of respiratory function becomes poor and the probability of MVDC is increased.

• 예술인문사회 융합 멀티미디어 논문지
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• 제8권5호
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• pp.417-425
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• 2018

본 논문에서는 조선해양 작업장에서 발생하는 중대재해를 줄이고 체계적인 안전관리를 위하여 ETA(event tree analysis)기반 시나리오 도출 및 ICT 기술접목을 통한 안전관리 구축방안을 제안한다. 안전보건공단과 (구)국민안전처의 통계결과 조선해양 관련 중대재해 중 가장 많이 발생하는 사고유형은 떨어짐이고, 주요사고원인은 안전대 미착용 및 안전대 고리 미체결이다. 이 문제를 해결하기 위해 ETA기반의 시나리오를 작성하여 안전사항에 따른 결과를 도출하고 이 결과를 바탕으로 사고예방을 위한 ICT 기술접목으로 해결방안을 제시한다. ETA 기반 시나리오 도출 및 ICT 기술접목을 통해 제안한 해결방안으로는 안전대 및 안전모 착용여부 감지시스템, 안전대 고리 체결여부 감지시스템, 안전거리 측정을 위한 걸이설비 측정시스템이다. 안전사항별 시스템을 통해 작업자의 떨어짐 위험을 줄여 사망확률을 낮출 수 있다. 제안한 방안을 통해 사고를 예방함으로써 조선해양 분야의 중대재해를 줄이고 체계적인 안전관리를 도모한다.