In this study, the degradation properties by temperature stress of Araldite Ⓡ rapid-curing epoxy resin used for inorganic cultural heritages, was identified. The tensile and tensile shear strength of durability decreased for 12,624 hours at temperatures of 40∼60℃. In terms of stability of external stress and temperature, the slow-curing epoxy was superior to the rapid-curing epoxy, and cultural heritage conservation plans should therefore consider the strength and stress properties of restoration materials. Color differences increased for 12,624 hours at temperatures of 40∼60℃, and glossiness decreased. Both color and gloss stability were weak, which necessitates the improvement of optical properties. Thermal properties (weight loss, decomposition temperature, and glass transition temperature) of adhesives are linked to mechanical properties. Interfacial properties of the adherend and water vapor transmission rates of adhesives are linked to performance variation. For porous media (ceramics, brick, and stone), isothermal and isohumid environments are important. For outdoor artifacts on display in museums, changes in physical properties by exposure to varying environmental conditions need to be minimized. These results can be used as baseline data in the study of the degradation
Background: Although estrogen receptor (ER) expression levels affect the prognosis of breast cancer, studies about progesterone receptor (PR) expression levels are insufficient, especially in young breast cancer (YBC). The purpose of this study was to compare clinical characteristics and prognosis according to PR expression levels in invasive breast cancer patients. Methods: A prospective cohort study was conducted to identify YBC patients with invasive carcinoma diagnosed at an age of less than 40 years old between 2013 and 2018. Clinicopathologic features and prognosis of ER-positive and human epidermal growth factor receptor 2 (HER2)-negative patients were investigated. Patients were stratified into strong PR (PR-positive cell proportion > 10%), low PR (PR-positive cell proportion = 1~10%), and PR-negative (PR-positive cell proportion < 1%). Results: Among 458 patients enrolled, 386 (84.3%), 26 (5.7%), and 46 (10.0%) were categorized into strong PR, low PR, and PR-negative groups, respectively. The median follow-up duration was 58.6 months. Compared with the strong PR group, low PR and PR-negative groups were more likely to have high Ki-67 and a high nuclear grade. Low R and PR-negative groups had significantly worse disease-free survival (DFS) and distant metastasis-free survival (DMFS) than the strong PR group (p = 0.0033, p = 0007). Low PR group had an even higher risk of distant metastasis than PR-negative patients. Low PR patients and PR-negative had significantly lower overall survival (OS) rates than strong PR. Conclusion: Low PR might be a prognostic factor of ER-positive/HER2-negative in YBC.
Background: Pathologic complete response (pCR) of breast cancer after neoadjuvant chemotherapy (NAC) is highly related to molecular subtypes. Patients who achieved tumor pCR after NAC have a better prognosis. However, despite of better prognosis, pCR patients have a potential for recurrence. There is little evidence of risk factors of recurrence in patients with pCR. We aim to analyze factors associated with tumor recurrence in patients who achieved pCR. Methods: This study retrospectively reviewed the data of patients diagnosed with breast cancer who achieved pCR after receiving NAC between January 2009 and December 2018 in Samsung Medical Center. pCR was defined as no residual invasive cancer in the breast and axillary nodes even if there is residual ductal carcinoma in situ (ypT0 or ypTis with ypN0). Breast cancers are classified into 4 subtypes based on hormone receptors (HR) and human epithelial growth factor receptor 2 (HER2) status. Patients who had bilateral breast cancer, inflammatory breast cancer, distant metastasis, unknown subtype, and histologically unique case were excluded from the study. Results: In total 483 patients were included in this study except for patients who corresponded to the exclusion criteria. The median follow-up duration was 59.0 months (range, 0.5-153.3 months). Breast cancer recurred in 4.1% of patients (20 of 483). There was a significant difference in clinical T (p = .004) and clinical N (p = .034) stage in the Kaplan-Meier curve for disease-free survival. Molecular subtypes (p = .573), Ki67 (p = 1.000), and breast surgery type (p = .574) were not associated with tumor recurrence in patients who achieved pCR after NAC. In the clinical T stage and clinical N stage, there was a significant difference between recurrence and no-recurrence groups (clinical T stage; p = .045, clinical N stage; p = .002). Univariable Cox regression revealed statistical significance in the clinical T stage (p = .049) and clinical N stage (p = .010), while multivariable Cox regression demonstrated non-significance in the clinical T stage (p = .320) and clinical N stage (p = .073). Conclusion: Results in this study showed that clinical T, clinical N stage, and molecular subtypes were not statistically significant predictors of recurrence in patients who achieved pCR after NAC. It is hypothesized that a multicenter-based study would lead to the identification of factors as predictors of recurrence after achieving pCR.
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