• Asian Pacific Journal of Cancer Prevention
• /
• v.16 no.2
• /
• pp.797-802
• /
• 2015

Background: The purpose of this study was to prospectively evaluate the predictive value of perfusion computed tomography (CT) for response of local advanced esophageal carcinoma to radiotherapy and chemotherapy. Materials and Methods: Before any treatment, forty-three local advanced esophageal squamous cell carcinomas were prospectively evaluated by perfusion scan with 16-row CT from June 2009 to January 2012. Perfusion parameters, including perfusion (BF), peak enhanced density (PED), blood volume (BV), and time to peak (TTP) were measured using Philips perfusion software. Seventeen cases received definitive radiotherapy and 26 received concurrent chemo-radiotherapy. The response was evaluated by CT scan and esophagography. Differences in perfusion parameters between responders and non-responders were analyzed, and ROCs were used to assess predictive value of the baseline parameters for treatment response. Results: There were 25 responders (R) and 18 non-responders (NR). Responders showed significantly higher BF (R:34.1 ml/100g/min vs NR: 25.0 ml/100g/min, p=0.001), BV (23.2 ml/100g vs 18.3 ml/100g, p=0.009) and PED (32.5 HU vs 28.32HU, P=0.003) than non-responders. But the baseline TTP (R: 38.2s vs NR: 44.10s, p=0.172) had no difference in the two groups. For baseline BF, a threshold of 36.1 ml/100g/min achieved a sensitivity of 56%, and a specificity of 94.4% for detection of clinical responders from non-responders. Conclusions: The results suggest that the perfusion CT can provide some helpful information for identifying tumors that may respond to radio-chemotherapy.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.34 no.8A
• /
• pp.633-639
• /
• 2009

For operation of IEEE 802.22 WRAN system, spectrum sensing is a essential function. However, due to strict sensing requirement of WRAN system, spectrum sensing process of CR nodes require long quiet period. In addition, CR nodes sometimes fail to detect licensed users due to shadowing effect of wireless communication environment. To overcome this problem, CR nodes collaborate with each other for increasing the sensing reliability or mitigating the sensitivity requirement. A general approach for decision fusion, the "k out of N" rule is often taken as the decision fusion rule for its simplicity. However, since k out of N rules can not achieve better performance than the highest SNR node when SNR is largely different among CR nodes, the local SNR of each node should be considered to achieve better performance. In this paper, we propose two novel data fusion methods by utilizing confidence vector which represents the confidence level of individual sensing result. The simulation results show that the proposed schemes improve the signal detection performance than the conventional data fusion algorithms.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.12 no.1
• /
• pp.75-84
• /
• 2017

It becomes more and more more important for the storage that supports high speed recording and stable access from network environment. As one field of basic science which produces massive astronomical data, VLBI(: Very Long Baseline Interferometer) is now demanding more data writing performance and which is directly related to astronomical observation with high resolution and sensitivity. But most of existing storage are cloud model based for the high throughput of general IT, finance, and administrative service, and therefore it not the best choice for recording of big stream data. Therefore, in this study, we design storage system optimized for high performance of I/O and concurrency. To solve this problem, we implement packet read and writing module through the use of libpcap and pf_ring API on the multi core CPU environment, and build a scalable storage based on software RAID(: Redundant Array of Inexpensive Disks) for the efficient process of incoming data from external network.

• The Bulletin of The Korean Astronomical Society
• /
• v.37 no.1
• /
• pp.75.1-75.1
• /
• 2012

We have observed the part of the second quadrant of the Galactic Plane in $^{13}CO(1-0)$ using the multibeam receiver system installed on the 14 m telescope at Taeduk Radio Astronomy Observatory. The target region (L=108 to 112.5) is the part of the $^{12}CO$ Outer Galactic Plane Survey (Heyer et al. 1998), and it is for the exact Galactic plane with the latitude range of +1 and -1 degree. Total of 48,000 spectra (about 9 square degees) were obtained on 50" grid. The selected velocity resolution is 0.63 km/sec and sensitivity per channel is 0.17 K, and the covered velocity is 320 km/sec. We developed a new reduction method, which effectively deals with a relatively noisy 3-dimensional database. The collected $^{13}CO$ database will be manipulated with pre-existing $^{12}CO$ data to get several physical parameters. As it is located in the second quadrant, the kinematic distances of the individual clouds, which will be identified, can be estimated relatively easily without any distance ambiguity. In this meeting we present the reduction method, statistics, and some channel maps, integrated intensity maps, and spatial-velocity maps. We intend to clarify any difference of their characteristics between the clouds in the Outer Galaxy and Inner Galaxy using our data base.

• Asian Pacific Journal of Cancer Prevention
• /
• v.15 no.17
• /
• pp.7043-7048
• /
• 2014

Inhibition of heat shock protein 90 (Hsp90) leads to inappropriate processing of proteins involved in DNA damage repair pathways after DNA damage and may enhance tumor cell radio- and chemotherapy sensitivity. To investigate the potentiation of antitumor efficacy of lidamycin (LDM), an enediyne agent by the Hsp90 inhibitorgeldanamycin (GDM), and possible mechanisms, we have determined effects on ovarian cancer SKOV-3, hepatoma Bel-7402 and HepG2 cells by MTT assay, apoptosis assay, and cell cycle analysis. DNA damage was investigated with H2AX C-terminal phosphorylation (${\gamma}H2AX$) assays. We found that GDM synergistically sensitized SKOV-3 and Bel-7402 cells to the enediyne LDM, and this was accompanied by increased apoptosis. GDM pretreatment resulted in a greater LDM-induced DNA damage and reduced DNA repair as compared with LDM alone. However, in HepG2 cells GDM did not show significant sensitizing effects both in MTT assay and in DNA damage repair. Abrogation of LDM-induced $G_2/M$ arrest by GDM was found in SKOV-3 but not in HepG2 cells. Furthermore, the expression of ATM, related to DNA damage repair responses, was also decreased by GDM in SKOV-3 and Bel-7402 cells but not in HepG2 cells. These results demonstrate that Hsp90 inhibitors may potentiate the antitumor efficacy of LDM, possibly by reducing the repair of LDM-induced DNA damage.

• Journal of the Microelectronics and Packaging Society
• /
• v.15 no.1
• /
• pp.7-18
• /
• 2008

This paper reviews the current development of an ultra-slim SiP for Radio Frequency (RF) application, in which three flip chips, additional passive components and Surface Acoustic Wave (SAW) filters are integrated side-by-side. A systematic investigation is carried out for the design optimization, process and reliability improvement of the package, which comprises several aspects: a design study based on the 3D thermo-mechanical finite element analysis of the packaging, the determination of stress, warpage distribution, critical failure zones, and the figuration of the effects of material properties, process conditions on the reliability of package. The optimized material sets for manufacturing process were determined which can reduce the number of testing samples from 75 to 2. In addition the molded underfilling (MUF) process is proposed which not only saves one manufacturing process, but also improves the thermo-mechanical performance of the package compared with conventional epoxy underfilling process. In the end, JEDEC's moisture sensitivity test, thermal cycle test and pressure cooker tests have also been carried out for reliability evaluation. The test results show that the optimized ultra-slim SiP has a good reliability performance.

• Korean Journal of Veterinary Research
• /
• v.44 no.1
• /
• pp.41-47
• /
• 2004

The alkaline single-cell gel electrophoresis (SCGE) assay, called the comet assay, has been applied to detect DNA damage induced by a number of chemicals and biological factors in vivo and in vitro. The DNA damage was analysed by tail moment (TM) and tail length (TL), which were markers of DNA strand breaks in SCGE. Human, mouse and rat peripheral blood lymphocytes (PBLs) were irradiated with different doses of $^{60}Co$ ${\gamma}$-rays, e.g. 1, 2, 4, and 8 Gy at a dose rate of 1 Gy/min. A dose-dependent increase in TM (p<0.01) and TL (p<0.01) was obtained at all the radiation doses (1-8 Gy) in human, mouse and rat PBLs. Mouse PBLs were more sensitive than human PBLs which were in turn more sensitive than rat PBLs when the treated dosages were 1 and 2 Gy. However, human PBLs were more sensitive than mouse PBLs which were in turn more sensitive than rat PBLs when the irradiation dosages were 4 and 8 Gy. Data from all three species could be fitted to a linear-quadratic model. These results indicated that there may be inherent differences in the radio-sensitivity among PBLs of mammalian species.

• Asian Pacific Journal of Cancer Prevention
• /
• v.14 no.8
• /
• pp.4647-4650
• /
• 2013

Background: Breast illumination was suggested as a simple method for breast cancer screening. BreastLight is a simple apparatus for this purpose. Objective: To evaluate the diagnostic performance of BreastLight as a screening tool of breast cancer in comparison to mammography and histopathology. Materials and Methods: This hospital-based cross sectional study was conducted in the mammography unit of the radiodiagnosis department at National Cancer Institute, Cairo University. All participants were subjected to breast examination with the BreastLight tool, mammography and ultrasonography. Suspicious cases were biopsied for histopathological examination which is considered as a gold standard. Results: The mean age of the participants was $46.3{\pm}12.4$ years. Breast illumination method had sensitivity, specificity, positive predictive value, negative predictive value and total accuracy of 93.0%, 73.7%, 91.4%, 77.8% and 88.2%, respectively in detection of breast cancer. Conclusions: Breast illumination method with BreastLight apparatus is a promising easy-to-use tool to screen for breast cancer suitable for primary health care physician or at-home use. It needs further evaluation especially in asymptomatic women.

• Journal of The Korean Astronomical Society
• /
• v.47 no.2
• /
• pp.49-67
• /
• 2014

A novel method to characterize the topology of the early-universe intergalactic medium during the epoch of cosmic reionization is presented. The 21-cm radiation background from high redshift is analyzed through calculation of the 2-dimensional (2D) genus. The radiative transfer of hydrogen- ionizing photons and ionization-rate equations are calculated in a suite of numerical simulations under various input parameters. The 2D genus is calculated from the mock 21-cm images of high-redshift universe. We construct the 2D genus curve by varying the threshold differential brightness temperature, and compare this to the 2D genus curve of the underlying density field. We find that (1) the 2D genus curve reflects the evolutionary track of cosmic reionization and (2) the 2D genus curve can discriminate between certain reionization scenarios and thus indirectly probe the properties of radiation-sources. Choosing the right beam shape of a radio antenna is found crucial for this analysis. Square Kilometre Array (SKA) is found to be a suitable apparatus for this analysis in terms of sensitivity, even though some deterioration of the data for this purpose is unavoidable under the planned size of the antenna core.

• Journal of Semiconductor Engineering
• /
• v.1 no.1
• /
• pp.13-30
• /
• 2020

Radio frequency (RF) energy harvesting technology have become a reliable and promising alternative to extend the lifetime of power-constrained wireless networks by eliminating the need for batteries. This emerging technology enables the low-power wireless devices to be self-sustaining and eco-friendly by scavenging RF energy from ambient environment or dedicated energy sources. These attributes make RF energy harvesting technology feasible and attractive to an extended range of applications. However, despite being the most reliable energy harvesting technology, there are several challenges (especially power conversion efficiency, output DC voltage and sensitivity) poised for the implementation of RF energy harvesting systems. In this article, a detailed literature on RF energy harvesting technology has been surveyed to provide guidance for RF energy harvesters design. Since signal strength of the received RF power is limited and weak, high efficiency state-of-the-art RF energy harvesters are required to design for providing sufficient DC supply voltage to wireless networks. Therefore, various designs and their trade-offs with comprehensive analysis for RF energy harvesters have been discussed. This paper can serve as a good reference for the researchers to catch new research topics in the field of RF energy harvesting.