• 한국전산구조공학회논문집
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• 제22권5호
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• pp.463-474
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• 2009

기존에 설치되어 있는 구조물의 양면대칭 패치보강은 항상 면내거동만을 유발하나 시공상 어려움이 있다. 반면에 일면 패치보강의 경우 인장력의 증가에 따라 중립축의 위치가 대칭이 아니므로 휨에 대한 강성도가 증가하게 되며, 결과적으로 적층판의 휨을 심화시키게 된다. 이 연구에서는 일면 패치보강된 적층판의 두께방향은 물론이고 원공주위의 응력집중계수를 산정하기 위해 p-수렴 완전층별모델을 제안하였다. 가정된 변위장의 정의를 위해, 임의의 층에서 변위-변형률 관계와 3차원 구성방정식은 2차원 및 3차원 계층적 형상함수의 조합이 사용된다. 원형경계의 기하형상을 나타내기 위해 초유한사상기법이 사용되며, 다른 외삽법을 사용하지 않고 각 층마다 절점에서의 응력값을 직접적으로 얻기위해 가우스-로바토 수치 적분이 수행되었다. 제안된 모델의 정확도와 단순성은 기존의 3차원 유한요소해석과 실험에 의해 구해진 결과들과의 비교를 통해 검증되었다. 또한 정사각형, 원형, 고리형 형상의 다양한 패치보강에 따른 휨효과를 조사하였다.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.321-321
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• 2017

Water availability in rainfed lowlands (RFL) is strongly affected by climate change. In RFL, rice plants are exposed to soil moisture fluctuations (SMF) but rarely to simple progressive drought as widely believed. Typical RFL field is characterized by a about 5-cm thick high bulk density hardpan layer underneath the cultivated layer at about 20 cm depth that impedes deep root development. Root system has the ability to develop in response to changes in SMF, known as phenotypic plasticity. We hypothesized that genotypes that can adapt to RFL have root plasticity. The roots can sharply respond to re-wetting after drought period and thus penetrate the hardpan layer when the hardpan is wet and so becomes relatively soft, and thus access water under the hardpan. This study aimed to identify CSSLs derived from a cross between Sasanishiki and Habataki which adapted to such RFL conditions. We used 39 CSSLs together with the parent Sasanishiki, which were grown in hydroponics and pot under transient soil moisture stresses (drought and then rewatering), and compared with continuously well-watered (WW) (control) up to 14 days after sowing (DAS), and 20 DAS, respectively. Based on the results of hydroponics and pot experiments, we selected a few lines, which were grown in the soil-filled rootbox with artificial hardpan layer and without artificial hardpan. For the rootbox without artificial hardpan, plants were grown under WW and transient soil moisture stresses for 49 DAS. While the rootbox with artificial hardpan, the plants were grown under WW (control) and SMF (WW up to 21 DAS, 1st drought (22-36 DAS), rewatering (37-44 DAS), and followed by 2nd drought (45-58 DAS)). Among the 39 CSSLs, only CSSL439 (SL39) consistently showed significantly higher shoot dry weight (SDW) than Sasanishiki under transient soil moisture stress conditions as well as SMF conditions in all the experiments. Furthermore, under WW, SL39 consistently showed no significant differences from Sasanishiki in shoot and root growth in most of traits examined. SL39 showed significantly greater total root length (TRL) than Sasanishiki under transient soil moisture stress, which is considered as phenotypic plasticity in response to rewatering after drought period. Such plastic root development was the key trait that effectively contributed to root elongation and branching during the rewatering period and consequently enhanced the root to penetrate hardpan layer when the soil penetration resistance at hardpan layer reduced. In addition, using the rootbox with artificial hardpan layer ($1.7g\;cm^{-3}$, heavily compacted), SL39 showed greater root system development than Sasanishiki under SMF, which was expressed in its significantly higher TRL, total nodal RL, and total lateral RL at hardpan layer as well as at below the hardpan layer. These results prove that SL39 has plasticity that enables its root systems to penetrate hardpan layer in response to rewatering. Under SMF, such root plasticity contributed to its higher gs and Pn.

• 대한두경부종양학회지
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• 제18권1호
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• pp.36-40
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• 2002

Background and Objectives: To determine if laser endoscopic microsurgery is a reliable and appropriate approach in the treatment of laryngeal carcinomas. Materials and Methods: Retrospective study of 62 patients treated with CO2 laser from June 1988 to November 2000 at Seoul National University Hospital for laryngeal squamous cell carcinoma. All patients were treated with curative intention. Fifty three untreated patients with laryngeal carcinoma (39 glottic and 14 supraglottic carcinoma patients) had primary carbon dioxide laser microsurgery. Nine radiation failure patients were treated. Postoperative radiotheray was done for 17 patients. Neck dissection was performed simultaneously for 4 supraglottic cases with cervical nodal metastasis. Mean follow-up duration was 40 months. Results: In primary laser surgery group, distribution of tumors (American Joint Committee on Cancer, 1997) were 38 cases with Tl, 13 cases with T2, 2 cases with T3. Cure rate was 88.7%(47/53) and local control rate was 92.5%(49/53). Larynx was preserved in 94%(50/53) of patients. The overall 5-year survival rate(Kaplan-Meier) was 81.5%. In radiation failure group, 56% of patients were recurred after laser surgery. Conclusion: Laser surgery could be a better treatment modality for early laryngeal cancers and selected advanced cases. Additional radiation therapy should be considered if resection margin is not satisfactory.

• Radiation Oncology Journal
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• 제30권3호
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• pp.117-123
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• 2012

Purpose: Although anemia is considered to be a contributor to intra-tumoral hypoxia and tumor resistance to ionizing radiation in cancer patients, the impact of pretreatment anemia on local control after neoadjuvant concurrent chemoradiotherapy (NACRT) and surgery for rectal cancer remains unclear. Materials and Methods: We reviewed the records of 247 patients with locally advanced rectal cancer who were treated with NACRT followed by curative-intent surgery. Results: The patients with anemia before NACRT (36.0%, 89/247) achieved less pathologic complete response (pCR) than those without anemia (p = 0.012). The patients with pretreatment anemia had worse 3-year local control than those without pretreatment anemia (86.0% vs. 95.7%, p = 0.005). Multivariate analysis showed that pretreatment anemia (p = 0.035), pathologic tumor and nodal stage (p = 0.020 and 0.032, respectively) were independently significant factors for local control. Conclusion: Pretreatment anemia had negative impacts on pCR and local control among patients who underwent NACRT and surgery for rectal cancer. Strategies maintaining hemoglobin level within normal range could potentially be used to improve local control in rectal cancer patients.

• Asian Pacific Journal of Cancer Prevention
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• 제16권1호
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• pp.65-69
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• 2015

Background: To evaluate the impact of adding taxanes to anthracycline-based regimens in the adjuvant setting in localized young female breast cancer patients on the overall survival (OS) and the disease free survival (DFS). Materials and Methods: This retrospective study included all female breast cancer patients who were candidates for adjuvant chemotherapy presenting to Kasr Al Ainy centre of clinical oncology and Cairo oncology centre (Cairo Cure) in the period from January 2005 till December 2010. Results: Our study included 865 patients, 732 of whom received anthracycline based regimens and 133 taxane based regimens. The mean age of patients was 39 years. After a median follow up of 50 months the median DFS was 48.4 months. Survival analysis indicated that the tumor size (>5cm vs. <5cm) p=0.001), nodal involvement (Yes vs. No) p=0.0001) and pathology (invasive lobular vs. ductal) p=0.048) affected DFS. As regards hormonal status, ER, PR and HER 2neu positive patients had longer DFS (p=0.001, 0.003, 0.106). On multivariate analysis DFS was affected by tumor size and lymph node involvement (p=0.014, 0.007). Subgroup analysis showed improvement in arms treated with taxanes in terms of DFS with positive Her2neu, ER and PR, but this was not statistically significant. Conclusions: Adding adjuvant taxanes to anthracyclines is beneficial for treatment of localized breast cancer among all subgroups, especially higher risk groups. The type of adjuvant chemotherapy regimens and tumor characteristics have direct effects on DFS.

• Asian Pacific Journal of Cancer Prevention
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• 제15권15호
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• pp.6397-6403
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• 2014

Background: Aberrant promoter hypermethylation has been recognized in human breast carcinogenesis as a frequent molecular alteration associated with the loss of expression of a number of key regulatory genes and may serve as a biomarker. The E-cadherin gene (CDH1), mapping at chromosome 16q22, is an intercellular adhesion molecule in epithelial cells, which plays an important role in establishing and maintaining intercellular connections. The aim of our study was to assess the methylation pattern of CDH1 and to correlate it with the expression of E-cadherin, clinicopathological parameters and hormone receptor status in breast cancer patients of Kashmir. Materials and Methods: Methylation specific PCR (MSP) was used to determine the methylation status of CDH1 in 128 invasive ductal carcinomas (IDCs) paired with the corresponding normal tissue samples. Immunohistochemistry was used to study the expression of E-cadherin, ER and PR. Results: CDH1 hypermethylation was detected in 57.8% of cases and 14.8% of normal adjacent controls. Reduced levels of E-cadherin protein were observed in 71.9% of our samples. Loss of E-cadherin expression was significantly associated with the CDH1 promoter region methylation (p<0.05, OR=3.48, CI: 1.55-7.79). Hypermethylation of CDH1 was significantly associated with age at diagnosis (p=0.030), tumor size (p=0.008), tumor grade (p=0.024) and rate of node positivity or metastasis (p=0.043). Conclusions: Our preliminary findings suggest that abnormal CDH1 methylation occurs in high frequencies in infiltrating breast cancers associated with a decrease in E-cadherin expression. We found significant differences in tumor-related CDH1 gene methylation patterns relevant to tumor grade, tumor size, nodal involvement and age at diagnosis of breast tumors, which could be extended in future to provide diagnostic and prognostic information.

• Asian Pacific Journal of Cancer Prevention
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• 제14권10호
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• pp.6081-6084
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• 2013

Objective: Both estrogen receptors, ER alpha ($ER{\alpha}$) and ER beta ($ER{\beta}$), are expressed in 50-70% of breast cancer cases. The role of $ER{\alpha}$ as a prognostic marker in breast cancer has been well established as its expression is negative correlated with tumor size and lymph node metastasis. $ER{\beta}$ is also a favorable prognostic predictor although this is less well documented than for $ER{\alpha}$. Materials and Methods: To explore whether ERs independently or together might influence clinical outcome in breast cancer, the correlation between the ERs with the clinicopathological features was analyzed in 84 patients. Results: $ER{\alpha}$ expression negatively correlated with tumor stage (r=-0.246, p=0.028) and tended to be negatively correlated with lymph node status (r=-0.156, p=0.168) and tumor size (r=-0.246, p=0.099). Also, $ER{\beta}$ was negatively correlated with nodal status (r=-0.243, p=0.028), as was coexpression of $ER{\alpha}$ and $ER{\beta}$ (p=0.043, OR=0.194, 95% CI= 0.040-0.953). Conclusion: Coexpression of ERs might serve as an indicator of good prognosis in breast cancer patients.

• Asian Pacific Journal of Cancer Prevention
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• 제17권12호
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• pp.5081-5086
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• 2016

Background: Pathological factors, based mainly on immunohistochemistry (IHC) and histological differentiation, are mostly used to differentiate breast cancer (BC) subtypes. Our present aim was to describe the characteristics and survival of a relapsing BC patient cohort based on clinico-pathologic subtypes determined for the primary tumors. Methods: We used a clinico- pathological definition of BC subtypes based on histological grade (HG), estrogen receptor (ER), progesterone receptor (PgR),and epidermal growth factor receptor type 2 (HER2) expression assessed by IHC. We determined variables associated with loco-regional recurrence (LRR), second primaries (SP), systemic recurrence (SR) and post-recurrence survival (PRS). Results: Out of 1,702 patients, 240 (14%) had an event defined as recurrence. Those with recurrent disease were significantly younger than those without,and were initially diagnosed at more advanced stages, with larger tumors, greater lymph nodal involvement and higher HG. With a median follow up of 61 months (1-250), 4.6% of patients without recurrence and 56.6% of patients with an event defined as recurrence had died. The median PRS for the LRR group was 77 months; 75 months for those who developed a SP and 22 months for patients with an SR (p <0.0001). In SR cases, the median PRS was shorter for ER- tumors than for ER+ tumors (15 vs. 26 months, respectively; p = 0.0019, HR 0.44; CI: 0.25-0.44). Conclusions: Subtype, defined through classic histopathologic parameters determined for primary tumors, was found to eb related to type of recurrence and also to prognosis after relapse.

• Asian Pacific Journal of Cancer Prevention
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• 제17권4호
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• pp.2137-2140
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• 2016

Background: Gall bladder cancer (GBC) usually presents as unresectable or metastatic disease. We conducted a feasibility study to evaluate the effect of neoadjuvant therapy (NAT) on radiologic downstaging and resectability in unresectable GBC cases. Materials and Methods: Patients with locally advanced disease were treated with chemoradiotherapy [CTRT] ( external radiotherapy (45Gy) along with weekly concurrent cisplatin $35mg/m^2$ and 5-FU 500 mg) and those with positive paraaortic nodes were treated with neoadjuvant chemotherapy [NACT (cisplatin $25mg/m^2$ and gemcitabine $1gm/m^2$ day 1 and 8, 3 weekly for 3 cycles). Radiological assessment was according to RECIST criteria by evaluating downstaging of liver involvement and lymphadenopathy into complete response (CR), partial response (PR), stable disease (SD) and progressive disease (PD). Results: A total of 40 patients were evaluated from January 2012 to December 2014 (CTRT=25, NACT=15). Pretreatment CT scans revealed involvement of hilum (19), liver infiltration (38), duodenum involvement (n=22), colon involvement (n=11), N1 involvement (n=11), N2 disease (n=8), paraaortic LN (n=15), and no lymphadenopathy (n=6). After neoadjuvant therapy, liver involvement showed CR in 11(30%), PR in 4 (10.5%), SD in 15 (39.4%) and lymph node involvement showed CR in 17 (50%), PR in 6 (17.6%), SD in 4 (11.7 %). Six patients (CTRT=2, NACT=4) with 66.6 % and 83% downstaging of liver and lymphnodes respectively underwent extended cholecystectomy. There was 16.6 % and 83.3% rates of histopathological CR of liver and lymph nodes. All resections were R0. Conclusions: Neoadjuvant therapy in unresectable gall bladder cancer results in a 15% resectability rate. This approach has a strong potential in achieving R0 and node negative disease. Radiologic downstaging (CR+PR) of liver involvement is 40.5% and lymphadenopathy is 67.5%. Nodal regression could serve as a predictor of response to neoadjuvant therapy.

• Asian Pacific Journal of Cancer Prevention
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• 제16권8호
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• pp.3485-3491
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• 2015

Background: Nodal invasion by colorectal cancer is a critical determinant in estimating patient survival and in choosing appropriate preoperative treatment. The present meta-analysis was designed to evaluate the diagnostic value of endorectal ultrasound (EUS) in preoperative assessment of lymph node involvement in colorectal cancer. Materials and Methods: We systematically searched PubMed, Web of Science, Embase, and China National Knowledge Infrastructure (CNKI) databases for relevant studies published on or before December 10th, 2014. The sensitivity, specificity, likelihood ratios, diagnostic odds ratio (DOR) and area under the summary receiver operating characteristics curve (AUC) were assessed to estimate the diagnostic value of EUS. Subgroup analysis and meta-regression were performed to explore heterogeneity across studies. Results: Thirty-three studies covering 3,016 subjects were included. The pooled sensitivity and specificity were 0.69 (95%CI: 0.63-0.75) and 0.77 (95%CI: 0.73-0.82), respectively. The positive and negative likelihood ratios were 3.09 (95%CI: 2.52-3.78) and 0.39 (95%CI: 0.32-0.48), respectively. The DOR was 7.84 (95%CI: 5.56-11.08), and AUC was 0.80 (95%CI: 0.77-0.84). Conclusions: This meta-analysis indicated that EUS has moderate diagnostic value in preoperative assessment of lymph node involvement in colorectal cancer. Further refinements in technology and diagnostic criteria are necessary to improve the diagnostic accuracy of EUS.