• Journal of the Korean Society for Precision Engineering
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• v.29 no.3
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• pp.279-288
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• 2012

The material removal mechanism in machining is significantly affected by the cutting edge geometry. Its effect becomes even more substantial when the depth of cut is relatively small as compared to the characteristic length which represents the shape and size of the cutting edge. Conventionally, radius or focal length has been employed as the characteristic length with the assumption that the shape of cutting edge is round or parabolic. However, in reality, there could be various ways to determine the radius or focal length even for the same tool edge profile, depending on the region to be considered as cutting edge in the measured profile and the constraints to be set in constructing the best fitted circle or parabola. In this regard, the present study proposes various models to determine the characteristic length in terms of radius or focal length. Their physical compatibility are validated by carrying out 2D orthogonal cutting experiments using inserts with a wide range of characteristic length ($30{\sim}180\;{\mu}m$ in terms of radius) and then by investigating the correlation between the characteristic length and the cutting forces. Such validation is based on the common belief that the larger the characteristic length is, the blunter the cutting edge is and the higher the cutting forces are. Interestingly, the results showed that the correlation is higher for the radius or focal length obtained with a constraint that the center of best fitted circle or the focus of the best fitted parabola should be on the bisectional line of the wedge angle of tool.

• Journal of Chest Surgery
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• v.25 no.11
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• pp.1254-1260
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• 1992

Rupture of the posterior left ventricular wall following mitral valve replacement is a rare but fatal complication. Over a 10 year period from August 25 1980 to November 27 1990, we have experienced 6 such patients among 884 cases of mitral valve replacement with 4 deaths and 2 survivors. One patient had a type I rupture and another a type II rapture with the remaining four patients having suffered type III ruptures. All of the ruptures were dis covered intraoperatively enabling prompt reinstitution of the cardiopulmonary bypass and subsequent cardioplegic arrest prior to repair. Overzealous removal of calcified valve leaflets seemed to be responsible for the single type I rupture, and untethering of the so called ventricular loop appeared to be the main mechanism responsible for the type III ruptures. The single type II rupture that had occurred seemed to have been caused by inadvertent laceration of the papillary muscle with resultant rupture of the posterior LV wall at the base of the papillary muscle. Among the type III ruptures, 2 patients required intraaortic balloon pump[IABP] support only for mechanical assistance and 1 patient required both the IABP and the Biomedicus LV assist device for successfull weaning following repair of the LV rupture Another patient with a type II rupture also required the circulatory assistance of both the IABP and the bio-medicus LV assist device for weaning from the bypass. Attention to meticulous technical considerations such as avoiding over aggressive removal of heavily calcified valvular tissue, preservation of as much mural leaflet tissue and chordal stuctures as possible seemed helpful in preventing this catastrophic complication from occurring. Fusion and fibrous stricture of the chordal structures appeared particularly conducive to the type II ruptures as a result of the increased susceptibility to papillary injury during operation.

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.7
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• pp.1037-1043
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• 2016

Epigenetic processes in the development of skeletal muscle have been appreciated for over a decade. DNA methylation is a major epigenetic modification important for regulating gene expression and suppressing spurious transcription. Up to now, the importance of epigenetic marks in the regulation of Pax7 and myogenic regulatory factors (MRFs) expression is far less explored. In the present study, semi-quantitative the real-time polymerase chain reaction (RT-PCR) analyses showed MyoD and Myf5 were expressed in activated and quiescent C2C12 cells. MyoG was expressed in a later stage of myogenesis. Pax7 was weakly expressed in differentiated C2C12 cells. To further understand the regulation of expression of these genes, the DNA methylation status of Pax7, MyoD, and Myf5 was determined by bisulfite sequencing PCR. During the C2C12 myoblasts fusion process, the changes of promoter and exon 1 methylation of Pax7, MyoD, and Myf5 genes were observed. In addition, an inverse relationship of low methylation and high expression was found. These results suggest that DNA methylation may be an important mechanism regulating Pax7 and MRFs transcription in cell myogenic differentiation.

• Progress in Medical Physics
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• v.27 no.3
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• pp.117-124
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• 2016

Intrafractional motion of patients, such as respiratory motion during radiation treatment, is an important issue in image-guided radiotherapy. The accuracy of the radiation treatment decreases as the motion range increases. We developed a control system for a robotic patient immobilization system that enables to reduce the range of tumor motion by compensating the tumor motion. Fusion technology, combining robotics and mechatronics, was developed and applied in this study. First, a small-sized prototype was established for use with an industrial miniature robot. The patient immobilization system consisted of an optical tracking system, a robotic couch, a robot controller, and a control program for managing the system components. A multi speed and position control mechanism with three degrees of freedom was designed. The parameters for operating the control system, such as the coordinate transformation parameters and calibration parameters, were measured and evaluated for a prototype device. After developing the control system using the prototype device, a feasibility test on a full-scale patient immobilization system was performed, using a large industrial robot and couch. The performances of both the prototype device and the realistic device were evaluated using a respiratory motion phantom, for several patterns of respiratory motion. For all patterns of motion, the root mean squared error of the corresponding detected motion trajectories were reduced by more than 40%. The proposed system improves the accuracy of the radiation dose delivered to the target and reduces the unwanted irradiation of normal tissue.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.343-343
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• 2014

We reported on the electrical, optical, structural and morphological properties fabricated by co-sputtering for use as an anode for organic solar cells (OSCs). By adjusting RF and DC power of $MoO_3$ and IZO targets during co-sputtering, we fabricated the $MoO_3$-IZO electrode with graded content of the $MoO_3$ on the IZO films. At optimized $MoO_3$ thickness of 20 nm, the $MoO_3$ graded IZO electrode showed a higher mobility ($33cm^2/V-Sec$) than directly deposited $MoO_3$ on IZO film ($26cm^2/V-Sec$). At visible range (400nm~800nm), optical transmittance of the $MoO_3$ graded IZO electrode is higher than that of directly deposited $MoO_3$ on IZO film. High mobility of $MoO_3$ graded on IZO is attributed to less interface scattering between $MoO_3$ and IZO. To investigate the feasibility of $MoO_3$ graded IZO films, we fabricated conventional P3HT:PCBM based OSCs with $MoO_3$ graded IZO as a function of MoO3 thickness. The OSC fabricated on the $MoO_3$ graded IZO anode showed a fill factor of 66.53%, a short circuit current of $8.121mA/cm^2$, an open circuit voltage of 0.592 V, and a power conversion efficiency of 3.2% comparable to OSC fabricated on ITO anode and higher than directly deposited $MoO_3$ on IZO film. We suggested possible mechanism to explain the high performance of OSCs with a $MoO_3$ graded IZO.

• Korean Journal of Microbiology
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• v.38 no.4
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• pp.218-218
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• 2002

Using two drugs, tunicamycin and brefeldin A, which affect protein processing, we investigated the intracellular processing mechanism of secreted aspartyl proteinase 1 (SAPl) of Candide albicans. Three intracellular forms of SAPI were detected by immunoblotting using menoclonal antibody (MAb) CAPl. Their molecular weights were approximately 40, 41 and 45 kDa, respectively. The 41 kDa protein is a glycoprotein and may be the same as the extracellular form judging by its molecular mass. The 40 kDa protein was the unglycosylated form and its molecular mass coincided with deglycosylated SAPl and the 45 kDa protein was also the unglycosylated form. Neither the 40 and 45 kDa proteins were detected in the culture supernatant of C. albicans. These suggested that the 40 and 45 kDa proteins might be intracellular precursor forms of SAPI. These results show that SAPI is translated as a 45 kDa precusor form in the endoplasmic reticulum and the 45 kDa precursor farm undergoes proteolytic cleavage after translocation into the Golgi apparatus, generating the 40 kDa precursor form. This 40 kDa precursor is converted into a 41 kDa mature form through glycosylation in the Golgi apparatus. The mature form of the 41 kDa protein is sorted into secretary vesicles and finally released into the extracellular space through membrane fusion. When the glycan region of SAPl was digested with N-glycosidase F, both stability and activity of the enzyme decreased. These results indicate that the glycan attached to the enzyme may, at least in parti be related to enzyme stability and activity.

• Korean Journal of Pharmacognosy
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• v.27 no.3
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• pp.231-237
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• 1996

The antitumor components of the protoplast fusants of Lentinula edodes and Ganoderma lucidum were examined for immunological activity to elucidate the mechanism of their antitumor activity. They did not show any direct cytotoxicity against tumor cells. But being examined for immunopotentiation activity, they increased the number of colonies in the bone marrow stem cells to 3.0 times. They also increased the activities of the acid phosphatase in activated macrophages to 2.1 times and the secretion of nitric oxide in RAW 264.7 to 2.2 times, respectively. They activated the components of the alternative complement pathway. In humoral immunity. they increased the activities of the alkaline phosphatase in differentiated B cells to 1.6 times and the number of plaque forming cells to 1.8 times, respectively. In cellular immunity, they restored the depressed response of delayed type hypersensitivity in tumor bearing mice to normal level.

• Archives of Pharmacal Research
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• v.28 no.8
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• pp.956-962
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• 2005

Leishmania virus (LRV)1-4 has been reported to produce a fusion of ORF2 and ORF3 via a programmed +1 frameshift in the region where ORF2 and ORF3 overlap (Lee et a/., 1996). However, the exact frameshift site has not been identified. In this study, we compared the frameshift efficiency of a 259bp (nt. 2565-2823), frameshift region of LRV1-4, and the 71 bp (nt. 2605-2678) sub-region where ORF2 and ORF3 overlap. We then predicted the frameshift site using a new computer program (Pseudoviewer), and finally identified the specific region associated with the mechanism of the LRV1-4's+1 frameshift by means of a mutational analysis based on the predicted structure of LRV1-4 RNA. The predicted structure was confirmed by biochemical analysis. In order to measure the frameshift efficiency, constructs that generate luciferase without a frameshift or with a+1 frameshift, were generated and in vitro transcription/translation analysis was performed. Measurements of the luciferase activity generated, showed that the frameshift efficiency was about $1\%$ for both the 259bp (LRV1-4 259FS) and 71 bp region (LRV1-4 71FS). Luciferase activity was strongly reduced in a mutant (LRV1-4 NH: nt. 2635-2670) with the entire hairpin deleted and in a mutant (LRV1-4 NUS: nt. 2644-2659) with the upper stem of the hairpin deleted. These results indicate that the frameshift site in LRV1-4's is in the 71 bp region where ORF2 and ORF3 overlap, and that nt. 2644-2659 (the upward hairpin stem) playa key role in generating the +1 frameshift.

• Journal of Digital Contents Society
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• v.10 no.1
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• pp.87-96
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• 2009

Digital Broadcast Service is being very popular and the delivery mechanism for digital broadcast content through IP network has progressed constantly, due to the advance of video and audio compression and network technologies. From these trends, in Korea, the commercial IPTV service starts in this year after the law related to IPTV is enacted last year. Since IPTV service, which integrates broadcast and communication services, can give an infrastructure for fusion of communication and interactive multimedia data service, IPTV service is attractive. Recently, by the advent of various wireless connection technologies and the mobile devices of high capability, Mobile IPTV, which has an advantage of not only IPTV but also mobile TV, has gained much interest. In this paper, we review a necessary ingredient for Mobile IPTV in the next generation wired/wireless convergence network environment which consists of heterogeneous wireless access networks. In addition, we propose the scheme for user mobility and service session mobility management using RTSP protocol and introduce the service gateway concept to guarantee the extension of IPTV service platform.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.6
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• pp.163-171
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• 2015

Personal Health Records(PHR) service offers patients a convenient and easy-to-use solution for managing their personal health records, crucial medical files, and emergency contacts. In spite of the indispensable advantages, PHR service brings critical challenges that cannot be avoided from consumer side if the security of the data is concerned. The problem of user's privacy infringement and leaking user's sensitive medical information is increasing with the fusion of PHR technology and healthcare. In this paper, therefore, we analyze the various security aspects that are vulnerable to the PHR service and needed to be resolved. Moreover, we analyze the security requirements from the point of view of the PHR users and application service providers and provides the PHR security mechanism for addressing PHR security threats and satisfying PHR security requirements.