• Radiation Oncology Journal
• /
• v.37 no.3
• /
• pp.149-155
• /
• 2019

In metastatic non-small cell lung cancer (NSCLC), the role of radiotherapy (RT) has been limited to palliation to alleviate the symptoms. However, with the development of advanced RT techniques, recent advances in immuno-oncology therapy targeting programmed death 1 (PD-1) and programmed death ligand 1 (PD-L1) and targeted agents for epidermal growth factor receptor (EGFR) mutation or anaplastic lymphoma kinase (ALK) translocation allowed new roles of RT in these patients. Within this metastatic population, there is a subset of patients with a limited number of sites of metastatic disease, termed as oligometastasis that can achieve long-term survival from aggressive local management. There is no consensus on the definition of oligometastasis; however, most clinical trials define oligometastasis as having 3 to 5 metastatic lesions. Recent phase II randomized clinical trials have shown that ablative RT, including stereotactic ablative body radiotherapy (SABR) and hypofractionated RT, to primary and metastatic sites improved progression-free survival (PFS) and overall survival (OS) in patients with oligometastatic NSCLC. The PEMBRO-RT study, a randomized phase II study comparing SABR prior to pembrolizumab therapy and pembrolizumab therapy alone, revealed that the addition of SABR improved the overall response, PFS, and OS in patients with advanced NSCLC. The efficacy of RT in oligometastatic lung cancer has only been studied in phase II studies; therefore, large-scale phase III studies are needed to confirm the benefit of local ablative RT in patients with oligometastatic NSCLC. Local intensified RT to primary and metastatic lesions is expected to become an important treatment paradigm in the near future in patients with metastatic lung cancer.

• Journal of Genetic Medicine
• /
• v.9 no.1
• /
• pp.1-10
• /
• 2012

About 7% of all breast cancer (BC) cases result from a genetic predisposition, and approximately 1,000 patients develop hereditary BC (HBC) every year in Korea. BRCA1 and BRCA2 are the primary genes underlying HBC. The average cumulative risks in BRCA1 mutation carriers at 70 years of age are 65% (95% confidence interval 44-78%) for BC and 39% (18-54%) for ovarian cancer (OC). The corresponding estimates for BRCA2 are 45% (31-56%) and 11% (2.4-19%), respectively. The penetrance of BRCA mutations is not the same between patients and can depend on factors such as race and birth-cohort. The Korean Hereditary Breast Cancer (KOHBRA) study is a large prospective nationwide study that includes 39 participating centers. Between May 2007 and May 2010, the first phase of the KOHBRA study was planned and fulfilled successfully. The primary aim of phase I was to estimate the prevalence of BRCA1/2 mutations and OC among a high-risk group of patients with HBC and their families. According to data collected during phase I of the study, the prevalence and penetrance of BRCA mutations were comparable to corresponding data from Western countries. For the second phase of the KOHBRA study, we are currently investigating a Korean BRCA mutation prediction model, prognostic factors in BRCA-related BC, environmental/genetic modifiers, and implementing a genetic counseling network. The final goal of the KOHBRA study is to create clinical practice guidelines for HBC in Korea. In this article, I review the genetics of HBC, summarize the characteristics of Korean HBC, and discuss current and future HBC research in Korea.

• Journal of Korean Society for Atmospheric Environment
• /
• v.19 no.E2
• /
• pp.89-97
• /
• 2003

Ambient polycyclic aromatic hydrocarbons (PAHs) were measured during the winter and summer of 2002 in Chongju. A filter pack and polyurethane foam (PUF) system was employed to collect simultaneously the particulate and gas phase PAHs. The samples were then analyzed using a gas chromatograph equipped with mass spectrometer detectors (GC/MSD). A total of 29 samples were collected and 11 PAH species were identified. The lower molecular weight PAH compounds (3∼4 rings) dominated the total PAH mass. The higher molecular weight PAH compounds (5∼6 rings) were less abundant. The PAHs were showed to exhibit seasonal variations. The concentrations of all com-pounds were significantly higher in winter than summer. The lower molecular weight PAHs were mostly found in the gas phase whereas the heavier ones were mainly associated with particulate phase. Vehicle emissions are likely to be the primary contributor of PAHs in Chongju. This study also demonstrated that it is necessary to perform simultaneously particulate and gas phase measurements to determine the accurate concentrations of ambient PAHs.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2012.05a
• /
• pp.356-363
• /
• 2012

This paper addresses an analytical study on the gas-solid two phase flows in a nozzle. The primary purpose is to get recognition into the gas-solid suspension flows and to investigate the particle motion and its influence on the gas flow field. The present study is the primal step to comprehend the gas-solid suspension flow in the convergent-divergent nozzle. This paper try to made a development of an analytical model to study the back pressure ratio, particles loading and the particle diameter effect on gas-solid suspension flow. Mathematical model of gas-solid two phase flow was developed based on the single phase flow models to solve the quasi-one-dimensional mass, momentum equations to calculate the steady pressure field. The influence of particles loading and particle diameter is analyzed. The results obtained show that the suspension flow of smaller diameter particles has almost same trend as that of single phase flow using ideal gas as working fluid. And the presence of particles will weaken the strength of the shock wave; the bigger particle will have larger slip velocity with gas flow. The thrust coefficient is found to be higher for larger particles/gas loading or back pressure ratio, but it also depends on the ambient pressure.

• Nuclear Engineering and Technology
• /
• v.54 no.3
• /
• pp.826-833
• /
• 2022

A two-phase natural circulation test using SMART integral test loop (SMART-ITL) was conducted to explore thermo-hydraulic phenomena of two-phase natural circulation in the SMART reactor. Specifically, the test examined the natural circulation in the primary loop under a stepwise coolant inventory loss while keeping the core power constant at 5% of the scaled full power. Based on the test results, three flow regimes were observed: single-phase natural circulation (SPNC), two-phase natural circulation (TPNC), and boiler-condenser natural circulation (BCNC). The flow rate remained steady in the SPNC, slightly increased in the TPNC, and dropped abruptly and maintained in the BCNC. Using a natural circulation flow map, the natural circulation characteristic in the SMART-ITL was compared with those in pressurized water reactor simulators. In the SMART-ITL, a BCNC regime appeared instead of siphon condensation and reflux condensation regimes because of the use of once-through steam generators.

• Proceedings of the Optical Society of Korea Conference
• /
• 2007.02a
• /
• pp.26-27
• /
• 2007

• Proceedings of the Korean Ceranic Society Conference
• /
• 2002.10a
• /
• pp.108.2-108
• /
• 2002

• Molecules and Cells
• /
• v.40 no.6
• /
• pp.401-409
• /
• 2017

The primary cilium is a non-motile microtubule-based organelle that protrudes from the surface of most human cells and works as a cellular antenna to accept extracellular signals. Primary cilia assemble from the basal body during the resting stage ($G_0$ phase) and simultaneously disassemble with cell cycle re-entry. Defective control of assembly or disassembly causes diverse human diseases including ciliopathy and cancer. To identify the effective compounds for studying primary cilium disassembly, we have screened 297 natural compounds and identified 18 and 17 primary cilium assembly and disassembly inhibitors, respectively. Among them, the application of KY-0120, identified as Brefeldin A, disturbed Dvl2-Plk1-mediated cilium disassembly via repression of the interaction of $CK1{\varepsilon}-Dvl2$ and the expression of Plk1 mRNA. Therefore, our study may suggest useful compounds for studying the cellular mechanism of primary cilium disassembly to prevent ciliopathy and cancer.

• Journal of Nutrition and Health
• /
• v.53 no.6
• /
• pp.563-569
• /
• 2020

Purpose: The vascular smooth muscle cells (VSMCs) in mature animals have implicated to play a major role in the progression of cardiovascular diseases such as atherosclerosis. This study aimed at optimizing the protocol in culturing primary VSMCs (pVSMCs) from rat thoracic aorta and investigating the effect of cellular zinc (Zn) deficiency on cell proliferation of the isolated pVSMCs. Methods: The thoracic aorta from 7-month-old Sprague Dawley rats was isolated, minced and digested by the enzymatic process of collagenase I and elastase, and then inoculated with the culture Dulbecco Modified Eagle Medium (DMEM) at 37℃ in an incubator. The primary cell culture morphology was observed using phase-contrast microscopy and cellular Zn was depleted using Chelex-100 resin (extracellular zinc depletion only) or 3 µM N,N,N',N'-tetrakis(2-pyridinylmethyl)-1,2-ethanediamine (TPEN) (extracellular and intracellular zinc depletion). Western blot analysis was used for the detection of SM22α and calponin as smooth muscle cell marker proteins and von Willebrand factor as endothelial cell marker protein to detect the culture purity. Cell proliferation by Zn depletion (1 day) was measured by MTT assay. Results: A primary culture protocol for pVSMCs from rat thoracic aorta was developed and optimized. Isolated cultures exhibited hill and valley morphology as the major characteristics of pVSMCs and expressed the smooth muscle cell protein markers, SM22α and calponin, while the endothelial marker von Willebrand factor was hardly detected. Zn deprivation for 1 day culture decreased rat primary vascular smooth muscle cell proliferation and this pattern was more prominent under severe Zn depletion (3 µM TPEN), while less prominent under mild Zn depletion (Chelexing). Conclusion: Our results suggest that cellular Zn deprivation decreased pVSMC proliferation and this may be involved in phenotypic modulation of pVSMC in the aorta.

• ETRI Journal
• /
• v.34 no.6
• /
• pp.892-899
• /
• 2012

We analyze a wideband spectrum in a cognitive radio (CR) network by employing the optimal adaptive multiband sensing-time joint detection framework. This framework detects a wideband M-ary quadrature amplitude modulation (M-QAM) primary signal over multiple nonoverlapping narrowband Gaussian channels, using the energy detection technique so as to maximize the throughput in CR networks while limiting interference with the primary network. The signal detection problem is formulated as an optimization problem to maximize the aggregate achievable secondary throughput capacity by jointly optimizing the sensing duration and individual detection thresholds under the overall interference imposed on the primary network. It is shown that the detection problems can be solved as convex optimization problems if certain practical constraints are applied. Simulation results show that the framework under consideration achieves much better performance for M-QAM than for binary phase-shift keying or any real modulation scheme.