Predicting the Response of Neoadjuvant Chemotherapy in Hormone Receptor-Positive, Human Epidermal Growth Factor Receptor 2-Negative Breast Cancer With Axillary Lymph Node Metastasis by Multigene Assay

Purpose: The GenesWell™ breast cancer test (BCT) is a recently developed multigene assay that predicts the risk of distant recurrence in patients with hormone receptor-positive (HR+) and human epidermal growth factor-2 negative (HER2-) early breast cancer (BC). The ability of this assay to predict the response to neoadjuvant chemotherapy (NACT) has not been established to date. Methods: Biopsy specimens from HR+/HER2- BC patients with axillary lymph node (LN) metastasis who underwent NACT were analyzed using the BCT score. The modified BCT score was developed and patients classified into high-and low-response groups. A total of 88 patients were available for the BCT score among the 108 eligible patients. The median follow-up duration was 35.9 (7.8-128.5) months. Results: Among them, 61 (65.1%) had cN1 and 53 (60.2%) had cT1 or cT2 disease. The BCT score was low in 25 (28.4%) patients and high in 63 (71.6%). Among the 50 patients with pathologic complete response or partial response, 41 (82.0%) were in the high BCT score group and 9 (18.0%) were in the low BCT score group. Among the 38 patients with stable or progressive disease, 22 (57.9%) were in the high BCT score group and 16 (42.1%) were in the low BCT score group (p = 0.025). Ki-67 before NACT was a significant factor for predicting tumor response (p = 0.006; 3.81 [1.50-10.16]). The BCT score showed a significant response to NACT (p = 0.016; 4.18 [1.34-14.28]). Distant metastasis-free survival was significantly different between the high- and low-response groups (p = 0.004). Conclusion: We demonstrated that the BCT score predicts NACT responsiveness in HR+/HER2- BC with LN metastasis and might help determine whether NACT should be performed. Further studies are required to validate these results.ope

그래핀과 이황화몰리브덴 전극의 제조 및 바이오센서로의 응용

학위논문 (박사)-- 서울대학교 대학원 공과대학 화학생물공학부, 2017. 8. 장정식.Biosensors have received substantial attentions in analytical chemistry owing to their potential for a wide range of applications. Compared to various sensing methods, electrochemical sensing method is a very attractive and powerful tool for high-performance biosensors. Electrochemical biosensors recognize a measurable electrical signal through a transducer, leading to high sensitivity, low power consumption, simple instrumentation, and short analysis time. Among electrochemical biosensors, field-effect transistor (FET)-based sensors are promising candidates because of their ability to rapidly and sensitively detect analytes via efficient interfacial transfer of charge carriers. Transducers play a crucial role in improving the performance of FET sensors. From a material viewpoint, the characteristics of transducer materials significantly affect the sensing performance. Therefore, it is important to develop and utilize enhanced transducer materials for FET-type biosensors. This dissertation describes CVD graphene and MoS2 as transducers for biosensor applications. Graphene, two-dimensinal (2D) structures with hexagonal lattice, comprises single- or few- layer of sp2-hybridized carbon atoms. Graphene has grabbed considerable focus owing to its outstanding thermal, mechanical, and electrical properties. Transition metal dichalcogenides (TMDs) are graphene-like 2D layered materials. Molybdenum disulfide (MoS2), which is a layered TMD, features high carrier mobility and low noise level. From these attractive properties, three different nanostructures based on graphene and MoS2 were used as transducers for biosensors. First, graphene was prepared via chemical vapor deposition (CVD) process. CVD graphene was applied to HBsAg and taste sensors. Second, the flower-like MoS2 nanospheres were fabricated using a simple hydrothermal method. After vapor deposition polymerization (VDP), carboxylated polypyrrole-coated nanospheres showed improved performance in As(III) sensor. Lastly, MoS2 nanosheets were grown on graphene surface by hydrothermal process. The nanocomposite was applied to a highly sensitive nonenzymatic sensor for H2O2 detection. These transducer materials can provide enhanced sensing performance with high sensitivity, good selectivity, and rapid response for various sensor applications.1. Introduction 1 1.1 Background 1 1.1.1 Biosensors 1 1.1.1.1 Recognition elements 4 1.1.1.2 Electrochemical sensing method 5 1.1.2 Transducer materials 9 1.1.2.1 CVD graphene 9 1.1.2.2 Transition metal dichalcogenide 13 1.1.2.3 Conducting polymers 16 1.1.3 Biosensor applications 19 1.1.3.1 Hepatitis B virus sensor 19 1.1.3.2 Taste sensor 20 1.1.3.3 Arsenic sensor 21 1.1.3.4 H2O2 sensor 23 1.2 Objectives and Outlines 25 1.2.1 Objectives 25 1.2.2 Outlines 25 2. Experimental Details 28 2.1 Fabrication of flexible graphene aptasensor for hepatitis B virus detection 28 2.1.1 Fabrication of CVD graphene 28 2.1.2 Fabrication of hepatitis B sensor based on binding aptamer-conjugated graphene electrodes 29 2.1.3 Preparation of saliva sample 30 2.1.4 Characterization of hepatitis B sensor based on binding aptamer-conjugated graphene electrodes 30 2.1.5 Instruments for the hepatitis B sensor 31 2.2 Fabrication of duplex bioelectronic tongue based on multiplexed graphene electrodes for sensing umami and sweet tastes 32 2.2.1 Fabrication of CVD graphene on SiO2 wafer substrate 32 2.2.2 Fabrication of duplex graphene electrodes 33 2.2.3 Immobilization of nanovesicles on the DGE surface 34 2.2.4 Preparation of target tastants 34 2.2.5 Characterization of duplex bioelectronic tongue based on multiplexed graphene electrodes 35 2.2.6 Sensing measurements for the umami and sweet taste sensor 36 2.3 Fabrication of highly sensitive FET-type aptasensor using flower-like MoS2 nanospheres for real-time detection of arsenic(III) 37 2.3.1 Materials 37 2.3.2 Fabrication of flower-like MoS2 nanospheres 37 2.3.3 Fabrication of carboxylated polypyrrole-coated FMNSs 38 2.3.4 Fabrication of FET-type aptasensor for As(III) detection 39 2.3.5 Instrumentation for the FET-type aptasensor 39 2.3.6 Sensing measurements for the As(III) aptasensor 40 2.4 Fabrication of H2O2 sensor based on MoS2 nanosheets grown on CVD graphene 41 2.4.1 Materials 41 2.4.2 Preparation of CVD graphene 41 2.4.3 Fabrication of MoS2 nanosheets grown on the graphene substrate 42 2.4.4 Characterization of MoS2 nanosheets grown on the graphene substrate 43 2.4.5 Instruments for the H2O2 sensor 44 3. Results and Disccusions 45 3.1 Fabrication of flexible graphene aptasensor for hepatitis B virus detection 45 3.1.1 Fabrication of graphene based-aptasensor for hepatitis B virus detection 45 3.1.2 Characterization of flexible CVD graphene electrodes 49 3.1.3 Characterization of aptamer-immobilized graphene electrodes 53 3.1.4 Electrical properties of FET-type hepatitis B aptasensor 56 3.1.5 Real-time responses of FET aptasensor toward HBsAg 60 3.1.6 Real-time responses of FET aptasensor toward real samples 66 3.2 Fabrication of duplex bioelectronic tongue based on multiplexed graphene electrodes for sensing umami and sweet tastes 70 3.2.1 Fabrication of duplex bioelectronic tongue 70 3.2.2 Characterization of duplex bioelectronic tongue 74 3.2.3 Electrical properties of duplex bioelectronic tongue 81 3.2.4 Real-time responses of the DBT for umami tastant 84 3.2.5 Real-time responses of the DBT for umami tastant in artificial seasonings 89 3.2.6 Real-time responses of the DBT for sweet tastant 91 3.2.7 Dual responses of the DBT for umami and sweet tastants 95 3.3 Fabrication of highly sensitive FET-type aptasensor using flower-like MoS2 nanospheres for real-time detection of arsenic(III) 99 3.3.1 Fabrication of carboxylated polypyrrole-coated FMNSs 99 3.3.2 Characterization of FMNSs 106 3.3.3 Characterization of CFMNSs 112 3.3.4 Immobilization of aptamers on CFMNS surfaces 117 3.3.5 Electrical characteristics of CFMNSs 121 3.3.6 Real-time responses of CFMNS aptasensor toward arsenite 125 3.3.7 Real-time response of MoS2 based-aptasensor toward a real sample 131 3.4 Fabrication of H2O2 sensor based on MoS2 nanosheets grown on CVD graphene 135 3.4.1 Fabrication of MoS2 nanosheets grown on graphene substrate 135 3.4.2 Characterization of MNSCG 139 3.4.3 Electrical properties of MNSCG 146 3.4.4 Real-time responses of FET-type H2O2 biosensor based on MNSCG electrode 149 3.4.5 Selective response and reusability of MNSCG sensor 154 4. Conclusion 158 Reference 164 국문초록 177Docto

사용자의 특성이 유료앱 구매에 미치는 영향에 관한 연구

학위논문 (석사)-- 서울대학교 대학원 : 경영학과, 2016. 2. 안중호.앱 경제라는 단어가 생길 정도로 스마트폰, 태블릿 PC등 모바일 기기의 보급률이 증가함에 따라 구글 스토어와 앱스토어와 같은 앱 시장을 통산 모바일 애플리케이션의 수요와 공급이 급증하며 앱 시장이 발전하고 있다. 하지만 이러한 시장의 변화에서 어떠한 특성을 가진 사용자가 유료 모바일 앱을 구매하는지에 관한 연구가 부족한 실정이다. 따라서 본 연구에서는 실제로 유료앱을 구매한 사용자의 데이터를 사용하여 사용자들의 어떠한 특성이 유료 앱 구매에 영향을 미치는지에 대하여 보고자 한다. 이를 위해 정보통신정책연구원이 2010년 부터 매해 실시해 온 한국미디어패널조사의 2014년 미디어 패널 개인 데이터를 사용하여 10,464명을 대상으로 연구를 실시하였다. 연구 결과, 음악 콘텐츠 소비, 게임 콘텐츠 소비, 신문 구독 여부, SNS 사용 여부, 지각된 위험이 모두 유료앱 구매에 영향을 주는 것으로 나타났다.제1 장 서 론 6 1.1 연구의 배경 6 1.2 연구의 목적 및 연구방법 8 제 2 장 문헌연구 10 2.1 경로 의존성 (Path Dependency) 10 2.2 사회인지이론 (Social Cognitive Theory) 12 2.3지각된 위험 이론 (Theory of Perceived Risk) 13 제 3 장 연구모형 및 가설 설정 15 3.1 연구모형 설계 15 3.2 가설 설정 17 3.2.1 콘텐츠 소비 17 3.2.2미디어 노출 18 3.2.3프라이버시와 유료앱 구매 20 제 4 장 연구 방법 23 4.1 연구 설계 및 자료 수집 23 4.2 측정 도구 24 4.2.1설문의 구성 24 4.3 표본 구성 24 4.4 자료의 분석 방법 26 제 5 장 실증 연구 결과 분석 27 5.1 측정 모형의 평가 27 5.1.1 신뢰도 분석 27 5.2 구조 모형의 평가 28 5.2.1 로지스틱 회귀분석 결과 28 제 6 장 연구 결과 분석 35 6.1 연구 결과의 요약 35 6.2 연구 결과에 대한 논의, 연구의 한계 및 향후 연구 방향 36 [참고문헌] 38 [Abstract] 45Maste

앤 피트리의 『거리』에 나타난 아메리칸 드림의 해체

This paper is an attempt to re-evaluate Ann Petrys The Street in light of the recent culturalist readings of the text that read Lutie as a negative character who has internalized the American dream and suggests that the black womens community comprised of Mrs. Hedges and Min should be viewed as an alternative to the hostile white society. The paper argues that contrary to this negative characterization, Lutie does not internalize the American dream and furthermore, is very much aware of the fictionality of the discourse of the American dream. Lutie, who perceives the fictional nature of the American dream embodies the Du Boisian double-consciousness. In this context, Sacvan Bercovitchs assertion that American dream is an ideological construct is much more useful in reading Petrys Street. In fact, the text can be read as a theoretical precedent to Bercovitchs theorization of the critique of the American dream. This paper goes on to demonstrate that through the figure of Junto who symbolizes the oppressive nature of capitalistic democracy in white America, the text deconstructs the American Dream by fundamentally questioning the validity of capitalistic democracy as a workable system for black women in the 1940s. The text suggests that the system of democratic capitalism is deeply flawed by showing the destructive forces brought on by the disfigured character Junto who embodies both white control of capital and the spirit of democracy gone awry. In this way, The Street refuses to be contained but rather subverts the existing order, compellingly contesting Bercovitchs argument that all narrative challenges to the American dream are already and always contained

Liver Inflammatory Pseudotumor Mimicking Cholangiocarcinoma

Inflammatory pseudotumor of the liver is a benign disease which is histologically characterized by plasma cell infiltration and reactive fibrotic inflammation. Differentiating this disease from malignant tumor is not easy. The authors report a case of inflammatory pseudotumor mimicked as intrahepatic cholangiocarcinoma. A 74-year-old man visited the emergency department complaining of jaundice and myalgia which have lasted for 1 to 2 weeks. After computed tomography (CT) scan and magnetic resonance imaging of the liver, he was initially diagnosed with intrahepatic cholangiocarcinoma, but was ultimately found to be inflammatory pseudotumor after pathologic examination of the liver tissue. His symptoms improved after a course of antibiotic therapy and conservative treatment, and the lesion disappeared on follow-up CT scanope

Development and Evaluation of Korean Nurses’ Core Competency Scale (KNCCS)

Purpose: The purpose of this study was to develop and evaluate a Korean Nurses’ Core Competency Scale (KNCCS). Methods: This methodological research was conducted over two major steps. The first step involved developing a preliminary 70-item KNCCS based on an extensive literature review and the standards and criteria proposed by the Korean Accreditation of Nursing. The second step involved evaluating validity and reliability of the KNCCS. 528 newly graduated nurses recently employed in nine major hospitals were participated in this research for validation. Results: The final KNCCS consisted of 70 items. The exploratory factor analysis identified five subscales under which each item could be categorized: 1) human understanding and communication skills; 2) professional attitudes; 3) critical thinking and evaluation; 4) general clinical performance; and 5) specific clinical performance. Conclusion: The KNCCS shows good reliability and validity. However, the test of both criterion and construct validity were recommended further.ope

Iatrogenic Injury in the Lateral Segment of the Liver after Pancreatoduodenectomy: Early Follow-Up CT Features and Clinical Implications

Purpose: To investigate the incidence, predisposing factors and image features of iatrogenically-induced focal parenchymal changes in the lateral segment of the liver after a pancreatoduodenectomy. Materials and Methods: A follow-up CT taken on the seventh day after an uneventful pancreatoduodenectomy were retrospectively reviewed for 123 patients for newly developed focal hepatic lesions. The location, size, and shape of the lesions were analyzed along with preoperative anatomic variation of the hepatic artery, for the degree of intrahepatic bile duct dilatation and procedure duration. Results: Other than two patients with hepatic metastases, 13 (10.6%) patients showed newly developed irregular (n = 9), linear (n = 2) or wedge-like (n = 2) hypovascular areas (1.4-8.5 cm; mean, 2.8 cm) in the posterior subcapsular portion of the lateral segment. There were only two patients (15.4%) with an aberrant origin of the segmental hepatic artery from the left gastric artery, and the degree of bile duct dilatation was nonspecific for the 13 subjected patients. Mean procedure time was not significantly different between the subjected patients and the others (541 min vs. 507 min; p = 0.160). Conclusion: Focal iatrogenic injury in the lateral segment after a pancreatoduodenectomy would not be a common event regardless of preoperative vascular anatomic variation, bile duct dilatation, or procedure duration.ope

Clinical Usefulness of 18F 2-Fluoro-2-Deoxy-D-Glucose Positron Emission Tomography Scan in the Diagnosis of Ampullary Carcinoma

PURPOSE: To evaluate the clinical usefulness of the 18F 2-fluoro-2-deoxy-D-glucose positron emission tomography (18F-FDG PET) scan in the diagnosis of the ampulla of Vater cancer. MATERIALS AND METHODS: CT images of 39 patients with ampulla of Vater cancer were reviewed regarding the lesion size, location, and bile or pancreatic duct dilatation. The patients were divided into three groups according to the lesion visibility on CT (Group A: visible mass, Group B: no visible mass but prominent ampulla, Group C: no visible lesion). Standardized uptake value (SUV) was measured on PET scan and the detection rate on PET images was comparable with that of CT images. RESULTS: Twenty-four patients (61.5%) were classified as Group A, 11 (28.2%) as Group B and 4 (10.3%) as Group C. All of Group A, 10 (90.9%) of Group B and 3 (75.0%) of Group C showed biliary dilatation. Pancreatic duct dilatation was shown in 18 (75.0%) of Group A, 9 (81.8%) of Group B, and 1 (25.0%) of Group C. The average of SUV of all patients was 5.90 +/- 3.1. Most (94.9%) of all patients showed high FDG uptake over 2.5 with 93.9% in Group B and C. CONCLUSION: 18F-FDG PET scan was use for the detection of ampulla of Vater cancer, even though the lesion was invisible on CT.ope

Diffusion-Weighted MRI of Malignant versus Benign Portal Vein Thrombosis

OBJECTIVE: To validate the diffusion-weighted MRI (DWI) for differentiation of benign from malignant portal vein thrombosis. MATERIALS AND METHODS: The Institutional Review Board approved this retrospective study and waived informed consent. A total of 59 consecutive patients (52 men and 7 women, aged 40-85 years) with grossly defined portal vein thrombus (PVT) on hepatic MRI were retrospectively analyzed. Among them, liver cirrhosis was found in 45 patients, and hepatocellular carcinoma in 47 patients. DWI was performed using b values of 50 and 800 sec/mm(2) at 1.5-T unit. A thrombus was considered malignant if it enhanced on dynamic CT or MRI; otherwise, it was considered bland. There were 18 bland thrombi and 49 malignant thrombi in 59 patients, including 8 patients with simultaneous benign and malignant PVT. Mean apparent diffusion coefficients (ADCs) of benign and malignant PVTs were compared by using Mann-Whitney U test. Diagnostic accuracy was evaluated using receiver operating characteristic (ROC) curve analysis. RESULTS: The mean ADC ± standard deviation of bland and malignant PVT were 1.00 ± 0.39 × 10(-3) mm(2)/sec and 0.92 ± 0.25 × 10(-3) mm(2)/sec, respectively; without significant difference (p = 0.799). The area under ROC curve for ADC was 0.520. An ADC value of > 1.35 × 10(-3) mm(2)/sec predicted bland PVT with a specificity of 94.6% (95% confidence interval [CI]: 84.9-98.9%) and a sensitivity of 22.2% (95% CI: 6.4-47.6%), respectively. CONCLUSION: Due to the wide range and considerable overlap of the ADCs, DWI cannot differentiate the benign from malignant thrombi efficiently.ope

Level of Combined Estrogen and Progesterone Receptor Expression Determines the Eligibility for Adjuvant Endocrine Therapy in Breast Cancer Patients

Hormone receptor (HR)-positive breast cancer has a heterogeneous pattern according to the level of receptor expression. Patients whose breast cancers express low levels of estrogen receptor (ER) or progesterone receptor (PgR) may be eligible for adjuvant endocrine therapy, but limited data are available to support this notion. We aimed to determine whether HR expression level is related to prognosis. Tumors from 6042 patients with breast cancer were retrospectively analyzed for combined HR levels of ER and PgR. Low expression was defined as ER 1-10% and PgR 1-20%. Four HR groups were identified by combining ER and PgR expression levels. Patients whose tumors expressed high levels of a single receptor showed the worst survival outcomes, and their risk continuously increased even after the 10-year follow-up. Endocrine therapy had a significant benefit for patients whose tumors expressed high HR levels and a favorable tendency for patients with tumors expressing low HR levels. We established the possible benefit of endocrine therapy for patients whose breast tumors expressed low HR levels. Thus, HR level was a prognostic factor and might be a determinant of extended therapy, especially for patients with high expression of a single receptor.ope