Ti-6Al-4V 재료를 사용한 레이저 분말 베드 용융법 (L-PBF)에서의 다물리 모델링 구축과 용융풀 특성화

학위논문(석사) -- 서울대학교대학원 : 공과대학 항공우주공학과, 2023. 2. 윤군진.This thesis introduces a method for predicting melt pool morphology during L-PBF (Laser-Powder Bed Fusion) process using computational fluid dynamics (CFD). The L-PBF process is one of the promising additive manufacturing (AM) processes, which stacks layers by repeating laying micrometer-sized powders on the build plate, melting and solidifying them. Similar to other metal AM processes, the L-PBF process enables engineers to design and produce complex geometries more quickly than conventional manufacturing processes such as cutting and casting. Furthermore, it leaves much less waste. Despite of L-PBFs versatilities, manufactured parts still suffer from various defects such as lack-of-fusion and keyhole. Analyzing the flow mechanisms in the melt pool is important to prevent these flaws, but it is complicated because of the extremely short time of the melting and solidifying process. Furthermore, distinct physical phenomena such as conduction, convection reflecting, evaporation, etc., are combined, which multiplies the complexity of investigating melt pool dynamics. To resolve this kind of problem, numerical simulation can be utilized. In this thesis, a multi-physics model for single-track/single-layer L-PBF is developed and used for evaluating the formation and evolution of melt pool with different processing parameters. The multi-physics model in this thesis considers phenomena such as multiphase flow, melting/solidification, conduction/convection heat transfer, capillary/thermo-capillary forces, recoil pressure, and material-dependent energy absorption. Also, this thesis mainly focuses on building a proper heat source model with a proper effective beam radius and energy absorptivity. The proposed simulation showed good agreement with the experimental results. Also, the numerical results presented that process parameters such as laser power and scan speed impacts significantly on the flows of molten metal and the formation of melt pool shape. As a result, the present study provides a better understanding of the mechanisms of flow dynamics in melt pools during the L-PBF process.본 학위논문은 전산유체해석 (CFD)를 적용하여 L-PBF (레이저 분말 베드 용융법)을 사용한 금속 적층 제조 공정 중 생성되는 용융풀의 형태를 예측하는 방법에 관한 논문이다. L-PBF 방식의 적층제조는 가장 신뢰성 높은 금속 적층 방식의 한가지로, 마이크로미터 사이즈의 분말을 빌드 플레이트 위에 고르게 도포하고 용융과 응고를 반복하며 층을 쌓으며 부품을 제조하는 방법이다. 다른 금속 적층 제조 방식과 마찬가지로, L-PBF 방식은 엔지니어로 하여금 주조나 절삭과 같은 기존 생산 공정으로는 제조할 수 없는 복잡한 형상을 보다 쉽고 빠르게 설계 및 생산을 가능케 하였다. 또한 적층 제조 방식은 폐기물의 발생이 적어 보다 효율적인 생산이 가능하다. 이렇듯 L-PBF 방식에는 다양한 장점이 있지만, L-PBF 공정 중 발생하는 융합 부족 또는 키홀 등의 결함은 부품의 품질을 저해하는 요인이 되고 있다. 이러한 결함 생성의 원인을 파악하고 방지하기 위해서 용융풀 내에서 발생하는 유동 흐름에 대해 분석하는 과정이 필요하지만, L-PBF 과정 중에 일어나는 용융 및 응고는 매우 짧은 시간에 일어나므로 분석이 쉽지 않다. 더욱이 전도, 대류, 복사 등의 열전달이 동시에 일어나고, 기화와 같은 물질 전달도 같이 일어나는 등 복잡한 물리 현상이 결합되어 나타나 용융풀 내 유동의 거동을 파악하는데 어려움을 더하고 있다. 따라서 이러한 문제를 해결하기 위해 전산 해석이 활용될 수 있다. 본 논문에서는 다양한 공정 변수를 가지는 단일 트랙/단일 레이어 L-PBF 공정에 대한 다물리 모델을 구축하여 용융풀의 발생과 성장을 평가하는데 활용하였다. 구축된 다물리 모델에는 다상유동, 용융/응고, 전도/대류 등의 열전달, 모세관힘, 반발압력, 레이저 흡수율 등 다양한 물리 현상들이 반영되었다. 본 논문에서 구축된 모델을 통해 실험 결과와 유사한 용융풀 형상을 얻을 수 있었다. 또한 전산 해석 결과를 통해 레이저 출력과 레이저 스캔 속도가 용융풀 내의 유동에 지대한 영향을 미침과 동시에 용융풀의 형상에도 큰 영향을 미침을 확인할 수 있었다. 결과적으로, 본 연구는 L-PBF 중 발생하는 용융풀 내의 유동 메커니즘에 대한 보다 넓은 이해를 제공하였다.Chapter 1. Introduction １ 1.1. Motivation １ Chapter 2. Backgrounds ３ 2.1. Metal additive manufacturing ３ 2.2. Melt Pool and Melting Modes ４ 2.3. Process Parameters ６ 2.4. Related Research ７ Chapter 3. Model Descriptions 10 3.1. Fluid Flow and Heat Transfer Model １1 3.1.1. Fluid Flow Model １1 3.1.2. Heat Transfer Model １3 3.2. Heat Source Model １4 3.3. Recoil Pressure and capillary forces 20 3.4. Powder Lay 21 3.5. Materials and Thermophysical Properties ２3 3.6. Model Establishment in Simulation ２6 3.6.1. Model without Powder ２7 3.6.2. Model with Powder ２8 Chapter 4. Results and Discussion ３3 4.1. Geometry and Morphology of the Melt Pool without Powder ３3 4.2. Geometry and Morphology of the Melt Pool with Powder ４2 4.3. Fluid Flow of the Melt Pool with Powder ４3 Chapter 5. Conclusion and Future Work ５2 5.1. Conclusions ５2 5.1. Future Work ５3 Reference ５5 국문초록 ５9석

한국의 온실가스 배출권거래제 시행이 기업 재무성과에 미친 영향에 관한 연구

학위논문 (석사) -- 서울대학교 대학원 : 행정대학원 글로벌행정전공, 2021. 2. 구민교.2015년에 체결된 ‘기후변화에 관한 파리협정’을 필두로 글로벌 환경규제가 심화되고 있다. 이는 화석연료 중심의 기존 에너지 사용 패러다임의 근본적인 전환을 요구하고 있다. 이러한 국제 추세는 한국을 비롯한 제조업 중심 국가들에 적지 않은 영향을 미칠 것으로 전망된다. 이에 본 연구에서는 한국의 온실가스 배출권 거래제(ETS) 1차 계획기간(2015-17) 시행결과 배출권 할당대상업체의 재무성과에 부정적 영향이 있었는지 검증하였다. 이를 위해 ETS 규제를 받지 않은 기업의 같은 기간 재무성과와 비교 분석하였다. 기업 규모나 업종 등을 통제하였을 때도 ETS 영향이 존재하는지 살펴보았다. 실험집단은 2014년 ETS 대상업체로 지정된 524개 업체 중, KIS-Line(기업정보포털)과 KIS-Value(기업정보서비스)를 통해 기업 재무정보 확인이 가능한 299개사(이상치 3개사 제외)이다. 통제집단인 ETS 규제를 받지 않은 기업은 코스피(KOSPI) 상장기업 중 비금융사로 설정하였으며, 업체수는 ETS 1차 계획기간 동안 본 연구에서 필요로 하는 기업 재무정보 확인이 가능한 380개사이다. 이중차분(DID) 분석 결과 ETS가 기업 재무성과에 반드시 부정적인 영향을 미친다고 볼 수 없었다. ETS 시행으로 매출은 유의하게 감소, 영업이익은 오히려 유의하게 증가하였으며, 자산수익률(ROA)은 통계적 유의성은 없지만 ROA 수치는 증가하는 등 ETS의 영향이 재무지표에 따라 일관되게 나타나지 않았다. ETS의 부정적 영향이 미미하고, 영업이익, 자산수익률 등에는 오히려 긍정적 영향을 미친 이유는 여러 가지로 추정해 볼 수 있다. 목표관리제(TMS) 등 ETS 시행 전 기업들이 이미 유사한 온실가스 규제를 경험하여 ETS에 쉽게 적응했을 가능성, ETS 1차 계획기간에 배출권을 100% 무상할당 하는 등 규제 강도가 낮았던 점, 기업들의 전체 생산비에서 에너지 비용이 차지하는 비중이 대체로 5% 미만으로 크지 않은 점, 기업들이 당장 심각한 재무적 타격을 겪지 않았으나 미래의 불확실성과 잠재적 리스크를 적극적으로 표명한 점 등이 당초 우려했던 만큼 재무성과에 큰 충격이 발생되지 않은 원인일 수 있다. 앞으로 정책 당국은 환경이슈의 특성을 고려해 장기 비전을 제시하고, 규제와 동시에 이행수단을 함께 제공할 필요가 있다. 적정한 규제의 강도와 규제의 속도 조절도 규제의 성공적 안착을 위해 필수적이다. 배출권 거래시장의 효율화를 위해 가격 상한제도 필요하다. 나아가 ETS의 상호 연계 및 외연 확대를 위해 국제사회의 ETS 참여를 독려하고, 에너지 효율 기술 및 환경설비 분야에 대한 국내기업의 진출도 적극 장려해야 한다. 끝으로, 본 연구는 ETS를 포함하여 미래에 지속적으로 심화될 에너지 및 환경규제에 대응하여 환경 정책과 산업 정책이 조화롭게 추진될 수 있는 방향성을 고민해 보았다. 환경정책의 지속 가능성과 성공 가능성도 결국 피규제집단인 기업들의 규제 순응과 규제의 적극적 활용에 달려있기 때문이다. 그러므로 엄격한 규제의 이행에 앞서 피규제집단의 규제 이행 능력에 대한 면밀한 검토가 선행되어야 한다. 규제이행 역량에 따라 차별화된 지원 대책도 마련되어야 한다. 또한 국가간에 환경 이슈를 형평성 있게 부담하려면 국제기구 등을 통해 ETS와 같이 한국이 앞서 있는 환경 정책을 알리고 회원국들의 적극적인 동참을 이끌어야 한다. 이는 비단 배출권 거래시장의 외연을 넓히는 의미로서만이 아니라, 국내 규제대상 집단에 대해 국내 환경규제의 당위성을 강조하기 위해서도 필수적인 정부의 역할이다.Global environmental regulations are deepening, such as the 2015 Paris Agreement on Climate Change. This calls for a fundamental shift in the existing energy use paradigm from fossil fuels. The global trend is likely to have a significant impact on countries with a high proportion of manufacturing like Korea. This study tried to verify that the financial performance of the companies subject to Korea’s emission trading scheme (ETS) was negatively affected by ETS Phase 1. To this end, this study compared the financial performance of the non-ETS regulated entities with that of the ETS-regulated entities over the same period. Besides, this study also looked at whether the ETS effect exists even when controlling the size of the company or industry. Out of 524 companies designated as ETS’s targets in 2014, the experimental group is 299 companies (excluded three outliers) that we were able to check corporate financial information through KIS-Line or KIS-Value. Among the KOSPI-listed companies, non-financial companies that ETS does not regulate were set as the control group. The number of companies in the control group is 380, which allows us to identify the financial information we need in this study during ETS Phase 1 (2015-17). As a result of the Difference-in-Difference (DID) analysis, we could not see that ETS necessarily harms corporate financial performance. With the implementation of ETS, revenue decreased significantly, operating profit rather increased significantly, and ROA was not statistically significant, but the ROA itself increased. Therefore, the impact of ETS did not appear consistently according to financial indicators. We can estimate various reasons why the negative impact of ETS was insignificant, and it had a rather positive impact on some indicators. Before the ETS, companies experienced similar greenhouse gas regulations such as the Target Management System (TMS) and were likely to have easily adapted to ETS. The fact that energy costs accounted for less than 5% of the total production cost which is not large, and that companies did not suffer a serious financial impact right away, but they actively expressed future uncertainty and potential risks may be the cause that did not give such a negative shock to financial performance. In the future, policy authorities need to present a long-term vision in consideration of the characteristics of environmental issues and provide measures for implementation at the same time. Adjusting the strength and speed of regulation as appropriate is also essential for the successful establishment of regulation. To make the emission trading market more efficient, a safety measure such as a price ceiling is also necessary. Furthermore, countries that are implementing the economy-wide ETS, including Korea, should encourage the international community to participate in ETS for mutual linkage and expansion of the carbon market. The policy authority also needs to actively encourage domestic companies to invest in energy-efficient technologies and environmental facilities. Finally, this study considered the direction in which environmental and industrial policies can be implemented harmoniously in response to the energy and environmental regulations. The sustainability and success of environmental policies largely depend on the compliance and active use of regulations by the regulated group. Therefore, the government needs careful consideration of the regulated groups' abilities to follow the regulatory standards. It should also prepare differentiated support measures for the regulated groups according to regulatory implementation capabilities. Also, it is necessary to inform Korea's leading environmental policies such as the economy-wide ETS through international organizations and lead the active participation of member countries to bear the environmental burden equally between countries. This is not only meant to expand the scope of the emission trading market, but also an essential role of the government to emphasize the legitimacy of domestic environmental regulations for groups subject to domestic regulations.Chapter 1. Introduction 1 1.1 Research Background 1 1.2 Research Subject and Scope 3 1.3 Differentiation from Previous Research 5 Chapter 2. Literature Review 7 2.1 Emission Trading Scheme 7 2.2 Corporate Financial Performance 14 2.3 Environmental Regulation and Innovation 15 2.4 Environmental Regulation and Competitiveness 20 Chapter 3. Research Design 23 3.1 Hypothesis 23 3.2 Methods 25 Chapter 4. Results 33 4.1 Descriptive Statistics 33 4.2 Results of Difference-in-Difference 37 4.3 Interpretation of Results 38 4.4 Policy Implications 42 Chapter 5. Conclusion 49 Bibliography 53 Abstract in Korean 59 Acknowledgment 62Maste

Oxaliplatin-induced Peripheral Neuropathy, Symptoms, Distress and Quality of Life among Korean Patients with Gastrointestinal Cancer

Purpose: This study was conducted to identify the level of oxaliplatin-induced peripheral neuropathy (OIPN), symptoms, distress, and quality of life (QoL) in gastrointestinal (GI) cancer patients and to identify the factors influencing QoL. Methods: A total of 123 patients were recruited for this cross-sectional study. Surveys used were the Therapy-Induced Neuropathy Assessment Scale (TNAS) for OIPN, the MD Anderson Symptom Inventory (MDASI-GI) for general symptoms associated with gastrointestinal cancer and its treatment, a distress thermometer, and the Euro Quality of Life Questionnaire 5-Dimensional Classification (EQ-5D) for QoL. Results: The patients were classified into three groups based on their treatment completion time (current, completed less than one year ago, completed more than one year ago). The scores of MDASI-GI and distress were significantly lower in patients who had completed chemotherapy compared to those who were undergoing treatment (p=.04 and .02 respectively). However, TNAS score was significantly higher in patients who completed chemotherapy less than one year ago than the other two groups (p=.001). In multivariate regression models, the OIPN and distress or general symptoms were identified as factors associated with QoL. Conclusion: In this study, we identified the symptoms that are factors related to the QoL in patients with GI cancer. In particular, the symptoms of OIPN are reported at significantly increased levels for patients who have finished chemotherapy less than one year ago, so efforts to prevent and manage the symptoms of OIPN are needed in this timeframe. To improve QoL of patients with GI cancer, continuous attention and care are required not only during the treatment of cancer but also after the completion of treatment.ope

Guidelines for Cancer Care during the COVID-19 Pandemic in South Korea

At the end of 2019, the cause of pneumonia outbreaks in Wuhan, China, was identified as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. In February 2020, the World Health Organization named the disease cause by SARS-CoV-2 as coronavirus disease 2019 (COVID-19). In response to the pandemic, the Korean Cancer Association formed the COVID-19 task force to develop practice guidelines. This special article introduces the clinical practice guidelines for cancer patients which will help oncologists best manage cancer patients during the COVID-19 pandemic.ope

위암에서 paclitaxel 저항 극복 방법으로서 CK2의 억제 효과

Dept. of Medicine/박사Despite advances in treatment, gastric cancer (GC) remains among the most fatal malignancies. Paclitaxel has been used treatment for GC, however, it has limited clinical efficacy owing to drug resistance development. Casein kinase (CK) 2 activation has been implicated in the proliferation of various tumor types and resistance to chemotherapy. Herein, we investigated the mechanistic basis for the association between CK2 activation and paclitaxel resistance. CK2 expression was evaluated by immunohistochemistry in formalin-fixed, paraffin-embedded tumor specimens from 59 advanced GC patients treated with paclitaxel as second-line therapy. Patients with high CK2 expression (29/59, 39%) showed lower disease control rate (47.7 % vs. 72.3 %, p=0.017) and shorter progression-free survival (2.8 vs. 4.8 months, p=0.009) than patients with low expression. CK2 protein expression was associated with sensitivity to paclitaxel in 49 GC cell lines. In SNU-1 line which showed paclitaxel resistance, high CK2 expression, and sensitivity to the CK2 inhibitor, 5-[(3-chlorophenyl)amino]-benzo[c]-2,6 naphthyridine-8-carboxylic acid (CX-4945), combination therapy with CX-4945 and paclitaxel exerted synergistic antiproliferative effects and inhibited of down signaling of phosphatidylinositol 3-kinase/AKT signaling. These results demonstrate that CK2 activation is related to paclitaxel resistance and that CX-4945 in combination with paclitaxel could be a treatment of choice for paclitaxel resistance in GC 진행성 위암은 치료 발전에도 불구하고, 여전히 예후가 않좋은 암중에 하나이다. 파클리탁셀은 위암의 주된 항암제 중에 하나이나, 저항기전으로 인해 그 효과는 제한적이다. 최근, Casein kinase 2 (CK2)의 활성화는 다양한 암종에서 종양의 증식과 연관되고, 항암제 저항성과 관계되는 연구가 보고되고 있다. 따라서, 본 연구는 위암에서, 파클리탁셀의 저항성과 CK2 활성화에 대해 조사하고자 하였다. 2차 약제로 파클리탁셀로 치료 받은 59명의 진행성 위암환자를 대상으로, 치료 전 종양조직을 이용하여 면역 화학 조직 염색법으로 CK2 발현을 조사하였다. CK2가 과발현 된 환자는 (29/59, 39%), CK2가 발현되지 않은 환자에 비해 질병 조절율이 통계학적으로 낮았으며 (47.7 % vs. 72.3 %, p=0.017), 무진행 생존율도 짧았다 (2.8 months vs. 4.8 months, p=0.009). 49개의 위암 세포주를 이용하여 파클리탁셀 및 CK2 억제제인 CX-4945에 대한 항증식효과를 조사한 결과 CK2 단백질의 과발현과 파클리탁셀의 저항성과 상관관계가 있었다. 49개의 위암세포주 중에 파클리탁셀에 저항성이 있으며, CK2 단백질이 과발현을 보이며, CX-4945에 민감한 세포 주인 SNU-1세포주를 선택하여, 파클리탁셀과 CX-4945와 병합 치료하였을 경우 항종양 상승효과가 있었으며, PI3K/AKT 경로를 통해 억제됨을 확인 하였다. 결론적으로, CK2 과발현은 위암에서 파클리탁셀의 저항성과 관련이 있었으며, paclitaxel과 CK2 억제제인 CX-4945를 병합치료는 파클리탁셀의 저항성을 극복하는 치료 방법이 될 수 있을 것이다.ope

Antibody-dependent cellular cytotoxicity-null effector developed using mammalian and plant GlycoDelete platform

Cancer therapy using immune checkpoint inhibitor antibodies has markedly shifted the paradigm of cancer treatment. However, methods completely eliminating the effector function of these signal-regulating antibodies is urgently required. The heterogeneity of glycan chains in antibodies limits their use as therapeutic agents due to their variability; thus, the development of uniform glycan chains is necessary. Here, we subjected the anti-programmed cell death protein (PD)-1 antibody nivolumab, a representative immune checkpoint inhibitor, to GlycoDelete (GD) engineering to remove the antibody-dependent cellular cytotoxicity (ADCC) of the antibody, leaving only one glycan in the Fc. Glyco-engineered CHO cells were prepared by overexpressing endo-β-N-acetyl-glucosaminidase (Endo T) in CHO cells, in which N-acetyl-glucosaminyl-transferase I was knocked out using Cas9. GD IgG1 nivolumab and GD IgG4 nivolumab were produced using GD CHO cells, and glycan removal was confirmed using mass spectrometry. Target binding and PD-1 inhibition was not altered; however, ADCC decreased. Furthermore, the IgG4 form, determined to be the most suitable form of GD nivolumab, was produced in a plant GD system. The plant GD nivolumab also reduced ADCC without affecting PD-1 inhibitory function. Thus, CHO and plant GD platforms can be used to improve signal-regulating antibodies by reducing their effector function.ope

Ipilimumab Real-World Efficacy and Safety in Korean Melanoma Patients from the Korean Named-Patient Program Cohort

PURPOSE: Ipilimumab improves survival in advanced melanoma patients. However, the efficacy and safety of ipilimumab has not been evaluated in Asian melanoma patients with a high frequency of mucosal and acral melanoma subtypes. MATERIALS AND METHODS: Advanced melanoma patients treated with 3 mg/kg ipilimumab in a Korean multicenter named-patient program (NPP) were evaluated between September 2014 and July 2015. Baseline characteristics and blood parameters including neutrophil to lymphocyte ratio (NLR) were assessed, and outcome and adverse events were evaluated according to subtypes. RESULTS: A total of 104 advanced melanoma patients were treated. The primary sites were acral (31.7%), mucosal (26%), cutaneous (26%), uveal (9.6%), and unknown (6.7%). Sixty-eight patients (65.4%) experienced adverse events, and the most common toxicity was skin rash (22.1%), 10 patients (9.6%) experienced adverse events of grade 3 or higher. The median progression-free survival (PFS) was 2.73 months (95% confidence interval, 2.67 to 2.85), and there was no difference in PFS according to subtypes. Poor performance status, liver metastasis, and NLR (≥ 5) were independent poor prognostic factors by multivariate analysis. CONCLUSION: In the Korean NPP cohort, ipilimumab showed similar efficacy and tolerability compared to Western patients, regardless of subtypes. All subtypes should benefit from ipilimumab with consideration of performance status, liver metastasis, and NLR.ope

S-1 Based Doublet as an Adjuvant Chemotherapy for Curatively Resected Stage III Gastric Cancer: Results from the Randomized Phase III POST Trial

PURPOSE: We conducted a randomized, multicenter, phase III trial to compare S-1 plus docetaxel (DS) with S-1 plus cisplatin (SP) as adjuvant chemotherapy for stage III gastric cancer patients. Materials and Methods: Stage III gastric cancer patients who had received curative gastrectomy with D2 lymphadenectomy were randomized into equal groups to receive adjuvant chemotherapy of eight cycles of DS (S-1 70 mg/m2 /day on days 1-14 plus docetaxel 35 mg/m2 on days 1 and 8) every 3 weeks or SP (S-1 70 mg/m2 /day on days 1-14 plus cisplatin 60 mg/m2 on day 1) every 3 weeks. The primary endpoint was 3-year disease-free survival (DFS) rate. RESULTS: Between November 2010 and July 2013, 153 patients (75 patients to DS and 78 patients to SP) were enrolled from 8 institutions in Korea. After the capecitabine plus oxaliplatin was approved based on the CLASSIC study, itwas decided to close the study early. With a median follow-up duration of 56.9 months, the 3-year DFS rate between two groups was not significantly different (49.14% in DS group vs. 52.5% in SP group). The most common grade 3-4 adverse event was neutropenia (42.7% in DS and 38.5% in SP, p=0.351). SP group had more grade 3-4 anemia (1.3% vs. 11.5%, p=0.037), whereas grade 3-4 hand-foot syndrome (4.1% vs. 0%, p=0.025) and mucositis (10.7% vs. 2.6%, p=0.001) were more common in DS group. Fifty-one patients (68%) in DS group and 52 (66.7%) in SP group finished planned treatment. CONCLUSION: Our findings suggest that SP or DS is an effective and tolerable option for patients with curatively resected stage III gastric cancer.ope

Korean Practice Guidelines for Gastric Cancer 2022: An Evidence-based, Multidisciplinary Approach

Gastric cancer is one of the most common cancers in Korea and the world. Since 2004, this is the 4th gastric cancer guideline published in Korea which is the revised version of previous evidence-based approach in 2018. Current guideline is a collaborative work of the interdisciplinary working group including experts in the field of gastric surgery, gastroenterology, endoscopy, medical oncology, abdominal radiology, pathology, nuclear medicine, radiation oncology and guideline development methodology. Total of 33 key questions were updated or proposed after a collaborative review by the working group and 40 statements were developed according to the systematic review using the MEDLINE, Embase, Cochrane Library and KoreaMed database. The level of evidence and the grading of recommendations were categorized according to the Grading of Recommendations, Assessment, Development and Evaluation proposition. Evidence level, benefit, harm, and clinical applicability was considered as the significant factors for recommendation. The working group reviewed recommendations and discussed for consensus. In the earlier part, general consideration discusses screening, diagnosis and staging of endoscopy, pathology, radiology, and nuclear medicine. Flowchart is depicted with statements which is supported by meta-analysis and references. Since clinical trial and systematic review was not suitable for postoperative oncologic and nutritional follow-up, working group agreed to conduct a nationwide survey investigating the clinical practice of all tertiary or general hospitals in Korea. The purpose of this survey was to provide baseline information on follow up. Herein we present a multidisciplinary-evidence based gastric cancer guideline.ope

A New Practical Desensitization Protocol for Oxaliplatin-Induced Immediate Hypersensitivity Reactions: A Necessary and Useful Approach

BACKGROUND AND OBJECTIVE: Desensitization protocols for patients with immediate hypersensitivity reactions (IHSRs) have proven to be effective, but they are not widely used in clinical practice because of impracticalities such as high cost, long procedure duration, and a lack of trained personnel. We aimed to determine the clinical characteristics of oxaliplatin-induced IHSRs and assess measures to protect against these reactions and to validate a new practical desensitization protocol. METHODS: We retrospectively reviewed 2640 cases of oxaliplatin IHSRs in 271 oxaliplatin users and prospectively used a newly designed desensitization protocol 32 times in 12 patients with hypersensitivity to platinum-based chemotherapy. The protocol consisted of increases in infusion rate every 15 minutes, regardless of the concentration of the chemotherapy agent in the infusion bags. RESULTS: Of the 271 patients administered oxaliplatin, 45 (16.6%) experienced IHSRs. Of 39 patients who experienced an IHSR but needed to continue oxaliplatin, 6 (15.4%) stopped treatment due to the reaction, and 33 (84.6%) continued despite the risk of further reactions. The new desensitization protocol was successfully completed in 12 patients (100%), but it was ineffective in 3 patients (all with a negative skin prick test), who experienced fever without urticaria. CONCLUSIONS: Many patients who experience oxaliplatin-induced IHSRs are required to stop first-line oxaliplatin-based chemotherapy or to continue without desensitization, with the associated risks. Our new desensitization protocol is practical and easy to use in clinical practice.ope