• Radiation Oncology Journal
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• 제21권1호
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• pp.100-106
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• 2003

Purpose : To develop a patients' setup verification tool (PSVT) to verify the alignment of the machine and the target isocenters, and the reproduclbility of patients' setup for three dimensional conformal radiotherapy (3DCRT) and intensity modulated radiotherapy (IMRT). The utilization of this system is evaluated through phantom and patient case studies. Materials and methods : We developed and clinically tested a new method for patients' setup verification, using digitally reconstructed radiography (DRR), simulation, porial and digital images. The PSVT system was networked to a Pentium PC for the transmission of the acquired images to the PC for analysis. To verify the alignment of the machine and target isocenters, orthogonal pairs of simulation images were used as verification images. Errors in the isocenter alignment were measured by comparing the verification images with DRR of CT Images. Orthogonal films were taken of all the patients once a week. These verification films were compared with the DRR were used for the treatment setup. By performing this procedure every treatment, using humanoid phantom and patient cases, the errors of localization can be analyzed, with adjustments made from the translation. The reproducibility of the patients' setup was verified using portal and digital images. Results : The PSVT system was developed to verify the alignment of the machine and the target isocenters, and the reproducibility of the patients' setup for 3DCRT and IMRT. The results show that the localization errors are 0.8$\pm$0.2 mm (AP) and 1.0$\pm$0.3 mm (Lateral) in the cases relating to the brain and 1.1$\pm$0.5 mm (AP) and 1.0$\pm$0.6 mm (Lateral) in the cases relating to the pelvis. The reproducibility of the patients' setup was verified by visualization, using real-time image acquisition, leading to the practical utilization of our software Conclusions : A PSVT system was developed for the verification of the alignment between machine and the target isocenters, and the reproduclbility of the patients' setup in 3DCRT and IMRT. With adjustment of the completed GUI-based algorithm, and a good quality DRR image, our software may be used for clinical applications.

• Journal of Astronomy and Space Sciences
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• 제20권4호
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• pp.283-298
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• 2003

The 2001 Leonid meteor storm has been observed all over the world, and its most intense flux since the last few decades has caused great interest among both laymen and experts. Especially, its maximum hours occurred at dawn hours of Nov. 19 in the east Asia, during which moonless clear night at the Mt. Bohyun allowed us near perfect condition of observation. Observation was carried out in the period of 01:00∼05:40(KST), which include the predicted maximum hours, with all-sky camera installed for upper atmospheric airglow research. Tn this paper we analyze 68 all-sky images obtained in this period, which contain records of 172 meteors. Utilizing the zenith hourly rate(ZHR) of 3000 and magnitude distribution index of 2, which were reported to International Meteor Organization by visible observers in the east Asia, we estimate the limiting magnitude of about 3 for meteors detected in our all-sky images. We then derive magnitudes of 83 meteors with clear pixel brightness outlines among the initially detected 172 meteors by comparing with neighbor standard stars. Angular velocities of meteors needed for computing their passing times over an all-sky image are expressed with a simple formula of an angle between a meteor head and the Leonid radiant point. The derived magnitudes of 83 meteors are in the range of -6∼-1 magnitude, and its distribution shows a maximum new -3mag. The derived magnitudes are much smaller than the limiting magnitude inferred from the comparison with the result of naked-eye observations. The difference may be due to the characteristic difference between nearly instantaneuous naked-eye observations and CCD observations with a long exposure. We redetermine magnitudes of the meteors by adjusting a meteor lasting time to be consistent with the naked-eye observations. The relative distribution of the redetermined magnitudes, which has a maximum at 0 mag., resembles that of the magnitudes determined with the in-principle method. The relative distribution is quite different from ones that decrease monotonically with decreasing magnitudes for meteors(1∼6) sensitive to naked-eye observations. We conclude from the magnitude distribution of our all-sky observation that meteors brighter than about 0 mag., appeared more frequently during the 2001 Leonid maximum hours. The frequent appearance of bright meteors has significantly important implication for meteor research. We noted, however, considerably large uncertainties in magnitudes determined only by comparing standard stars due to the unknown lasting time of meteors and the non-linear sensitivity of all-sky camera.

• Anatomy & Biological Anthropology
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• 제31권4호
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• pp.133-142
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• 2018

3D histology is a imaging system for the 3D structural information of cells or tissues. The synchrotron radiation propagation phase contrast micro-CT has been used in 3D imaging methods. However, the simple phase contrast micro-CT did not give sufficient micro-structural information when the specimen contains soft elements, as is the case with many biomedical tissue samples. The purpose of this study is to develop a new technique to enhance the phase contrast effect for soft tissue imaging. Experiments were performed at the imaging beam lines of Pohang Accelerator Laboratory (PAL). The biomedical tissue samples under frozen state was mounted on a computer-controlled precision stage and rotated in $0.18^{\circ}$ increments through $180^{\circ}$. An X-ray shadow of a specimen was converted into a visual image on the surface of a CdWO4 scintillator that was magnified using a microscopic objective lens(X5 or X20) before being captured with a digital CCD camera. 3-dimensional volume images of the specimen were obtained by applying a filtered back-projection algorithm to the projection images using a software package OCTOPUS. Surface reconstruction and volume segmentation and rendering were performed were performed using Amira software. In this study, We found that synchrotron phase contrast imaging of frozen tissue samples has higher contrast power for soft tissue than that of non-frozen samples. In conclusion, synchrotron radiation propagation phase contrast cryo-microCT imaging offers a promising tool for non-destructive high resolution 3D histology.

• Journal of Animal Science and Technology
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• 제49권5호
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• pp.677-688
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• 2007

돼지를 포함한 대부분의 동물은 일정한 발정주기를 가지고 일정한 시기에 배란을 하는 자연배란동물이지만, 토끼, 고양이, 밍크 등의 암놈은 교미자극에 의해 배란이 일어나는 유기배란동물이다. 또한 1년에 한 번만 발정하는 단발정동물과 1년에 수차례 발정하는 다발정동물이 있다. 이 중에서 모돈은 1년에 수차례 발정하는 다발정 동물로서 발정기에 들면 비발정기와는 다른 행동을 나타낸다(Diehl 등, 2001). 양돈가의 수익을 최대화하기 위해서는 비생산일수를 최소로 줄여야 한다. 모돈의 비생산일수를 줄일 수 있는 한 가지 방법은 성공적으로 교배를 시키는 것이다. 이처럼 성공적으로 교배를 시키기 위해서는 수정적기를 정확히 예측해야 한다. 만약 수정적기를 정확히 판단하지 못하여 수태가 되지 않으면, 비생산일수가 늘어나 손실을 입게 된다. 따라서 수정적기를 정확히 판단하는 것은 모돈의 성공적인 인공수정에 있어서 중요한 요소이다. 수정적기는 배란이 일어나기 전 10시간에서 12시간 사이이며, 발정이 시작되는 시점을 기준으로 하였을 때 경산돈의 경우 26시간에서 34시간 사이이고 미경산돈의 경우는 18시간에서 26시간 사이이다(Evans 등, 2001). 현재 하루에 두 번 모돈의 발정을 확인하는 것이 일반화되어 있으며, 이 때 웅돈을 접촉시키거나 육안관찰을 통하여 발정 유무를 판단한다. 이러한 방법에는 숙련된 기술과 풍부한 경험이 요구될 뿐만 아니라 총 소요노동력의 30% 정도가 요구된다(Perez 등, 1986). 하루에 두 번밖에 발정을 감지하지 않기 때문에 발정이 언제 시작되었는지를 정확히 알 수 없으며, 또한 발정의 대부분이 새벽에 시작되므로 수정적기를 정확히 판단하기란 매우 어렵다. 만약 발정을 감지했더라도 적기에 인공수정을 하지 못한다면, 수태율이 낮아지므로 경제적 손실이 초래된다. 현재 이러한 문제점 때문에 2회에서 3회에 걸쳐 인공수정을 하고 있으나 이에 따른 소요비용과 소요노동력 등은 양돈가의 부담을 가중시키는 요인이 되고 있다. 돼지는 발정기가 되면 비발정기에 나타내지 않던 외음부의 냄새를 맡는 행동, 귀를 세우는 행동 및 승가허용 행동 등을 나타낸다(Diehl 등, 2001). 또한 돼지는 비발정기에 비하여 발정기에 더 많은 활동량을 나타낸다(Altman, 1941; Erez and Hartsock, 1990). Freson 등(1998)은 스톨에서 개별적으로 사육되고 있는 모돈의 활동량을 적외선센서를 이용하여 측정함으로써 발정을 86%까지 감지하였다고 보고하였다. 그러나 이 연구는 단지 모돈의 발정을 감지하였을 뿐 번식관리에 있어서 가장 중요한 수정적기의 판단 기준을 제시하지 못하였다. 따라서, 본 연구는 스톨에서 사육되는 모돈의 활동량을 측정함으로써 발정시작시각을 감지하고 이를 기준으로 인공수정적기를 예측할 수 있는 인공수정적기 예측 장치를 개발한 후 이의 성능을 농장실증실험을 통하여 시험하고자 수행되었다.

• The KIPS Transactions:PartB
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• 제11B권3호
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• pp.281-288
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• 2004

In order to extract and analyze complex features of the behavior of animals in response to external stimuli such as toxic chemicals, we implemented an adaptive computational method to characterize changes in the behavior of chironomids in response to treatment with the insecticide, diazinon. In this paper, we propose an energy minimization model to extract the features of response behavior of chironomids under toxic treatment, which is applied on the image of velocity vectors. It is based on the improved active contour model and the variations of the energy functional, which are produced by the evolving active contour. The movement tracks of individual chironomid larvae were continuously measured in 0.25 second intervals during the survey period of 4 days before and after the treatment. Velocity on each sample track at 0.25 second intervals was collected in 15-20 minute periods and was subsequently checked to effectively reveal behavioral states of the specimens tested. Active contour was formed around each collection of velocities to gradually evolve to find the optimal boundaries of velocity collections through processes of energy minimization. The active contour which is improved by T. Chan and L. Vese is used in this paper. The energy minimization model effectively revealed characteristic patterns of behavior for the treatment versus no treatment, and identified changes in behavioral states .is the time progressed.

• The Journal of Korean Physical Therapy
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• 제15권4호
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• pp.1-12
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• 2003

The purpose of this study was to investigate the effect of high voltage pulsed current stimulation (HVPCS) on the healing rate of a dermal wound in a rat. We also determined the mechanism of promoting healing by HVPCS. Twenty male Sprague-Dawley rats were randomly divided into two group; HVPCS group (n=10) and control group (n=10). The HVPCS rats received electrical stimulation with a current intensity of 50 V at 100 pps for a duration of 30 minutes, while the control group was given the same treatment without electricity for a week. The biopsy specimens were fixed in formalin, embedded in paraffin and stained with Masson's trichrome, hematoxylin and eosin (H&E). The fibroblasts and collagen density were counted using a light microscope and computerized image analysis system and calculated as the density and the percent. A Student t-test showed a significantly higher wound healing rate of the HVPCS group than control (t=-4.161, p<0.001). The fibroblasts in the HVPCS group were higher than in the control group (t=-4.921, p<0.001). The density of collagen in the HVPCS group was also higher than in the control group (t=-4.367, p<0.001). These results indicate that the HVPCS accelerated the rate of healing in dermal wound, and increased fibroblasts and collagen density in the regenerative dermis. These findings suggest that the HVPCS may activate fibroblasts by alteration of the electrical environment, and it may increase collagen synthesis in the regenerative dermal wound.

• Journal of Korean Biological Nursing Science
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• 제1권1호
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• pp.25-41
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• 1999

Physiological activity of osteoblast including bone formation is known to be closely related to the increase of intracellular $Ca^{2+}$ activity($[Ca^{2+}]_i$) in osteoblast. $Ca^{2+}$ is an important intracellular messenger in diverse cellular functions, and regulation of its level is mediated by the transmembrane $Ca^{2+}$ movement via $Ca^{2+}$ channels, $Na^+-Ca^{2+}$ exchange, and by intracellular $Ca^{2+}$ movement through the intracellular stores. The purpose of this study is to investigate how the intracellular $Ca^{2+}$ is regulated in osteoblast-like cells(OLCs) by measuring $Ca^{2+}$ activity with cell imaging technique. OLCs were isolated from femur and tibia of neonatal rats, and cultured for 7 days. Cultured OLCs were loaded with a $Ca^{2+}$-sensitive fluorescent dye, Fura-2, and fluorescence images were monitored with a cooled CCD camera. The images were processed and analyzed with an image analyzing software. The results were as follows. (1) $[Ca^{2+}]_i$ of OLC decreased as the $Ca^{2+}$ concentration in the superfusing Tyrode solution was lowered. When $Na^+$ concentration in the superfusing solution was decreased, $[Ca^{2+}]_i$ increased.. These suggest that $Ca^{2+}$ flux occurs via the $Na^+-Ca^{2+}$ exchange mechanism. (2) When $Na^+$ in the superfusing solution was removed. a transient $Ca^{2+}$, increase($Ca^{2+}$ spike) was occasionally observed. However, $Ca^{2+}$ spike was not observed after adding 1 ${\mu}M$ thapsigargin. This implies that the generation of $Ca^{2+}$ spike is mediated by the release of $Ca^{2+}$ from endoplasmic reticulum(ER). (3) As the $Ca^{2+}$ concentration in the superfusing solution was raised, the frequency of 0mM $Na^+$-induced $Ca^{2+}$ spike increased, suggesting that $Ca^{2+}$-induced $Ca^{2+}$ release(CICR) mechanism exists. (4) After $[Ca^{2+}]_i$ was decreased with the superfusion of $Ca^{2+}$-free solution containing thapsigargin, the recovery of $[Ca^{2+}]_i$ with reperfusion of 2.5mM $Ca^{2+}$ solution transiently exceeded the control level, suggesting that the depletion of $Ca^{2+}$ in ER induces $Ca^{2+}$ influx from extracellular medium via store-operated $Ca^{2+}$ influx(SOCI) mechanism. (5) $[Ca^{2+}]_i$ was not affected by the superfusion of 25mM $K^+$ Tyrode solution. These results suggest that intracellular $Ca^{2+}$ activity in osteoblast is regulated by transmembrane $Ca^{2+}$ flux via $Na^+-Ca^{2+}$ exchange, $Ca^{2+}$ release from the internal store (ER) via $Ca^{2+}$-induced $Ca^{2+}$ release, and store-operated $Ca^{2+}$ influx across the cell membrane.

• The Journal of Korean Physical Therapy
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• 제11권3호
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• pp.81-87
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• 1999

The purpose of this study was to determine the effect of electrical stimulation on the number of MCs and percent of degranulated MCs in rat skin. Twelve male Sprague-Dawley rats were divided into two group; electrical stimulation group (n=6) and control group (n=6). Each animals hair on the back was removed. The electrical stimulation group received an positive rectangular pulsed electrical stimulation, while the control group was given the same treatment without electricity. The biopsy specimens were fixed in formalin, embedded in paraffin and stained with toluidine blue-nuclear fast red and alcian blue-safranin O. respectively. The MCs were counted using a light microscope and computerized image analysis system and calculated as the density and the percent. A t-test showed a significantly higher density of MCs in the electrical stimulated rats than control rats(p<0.05), and the percent of degranulated MCs in the electrical stimulated rats was higher than in the control rats (p<0.05) in toluidine blue stained sections. The density of MCs was significantly higher in the electrical stimulated rats than the control rats in alcian blue-safranin O Stained sections (P<0.01). An analysis of variance showed that the densities of CTMCs was significantly lower than the densities of MMCs and mixed MCs in electrical stimulated rat in alcian blue-safranin O Stained sections (p<0.05). These results suggest that the electrical stimulation may have potential for increasing the number of MCs and lead to degranulate the MCs in rat skin.

• Journal of the Institute of Electronics and Information Engineers
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• 제50권5호
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• pp.183-190
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• 2013

In this paper, we propose an improved anisotropic diffusion model for micro-crack detection in heterogeneously textured surface of polycrystalline solar wafers. Due to the nature of the image sensor, the gray-level of the diagonal micro-crack is non-uniform. Thus, the conventional algorithms can't fully detect diagonal micro-cracks when the number of iteration is not enough. However, the increasing of the iteration number leads to increase computation time and detects micro-crack thicker than the original micro-crack. In order to overcome this drawback, we use the gradient of north, south, east, and west directions as well as extended directions. To calculate the diffusion coefficients, we compare the gradients of conventional directions and extended directions and apply the larger gradient values to the coefficient function. This is because the proposed method reflects the information of diagonal micro-crack. Comparing to Tsai et al.'s and Ko and Rheem's, the proposed algorithm shows superior efficiency in detecting the diagonal micro-cracks with less iterations in the images of polycrystalline solar wafers. In addition, it also shows that the thickness of segmented micro-crack is similar to the orignal micro-crack.

• Publications of The Korean Astronomical Society
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• 제30권2호
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• pp.559-563
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• 2015

Monitor of All-sky X-ray Image (MAXI) is a Japanese X-ray all-sky surveyer mounted on the International Space Station (ISS). It has been scanning the whole sky since 2009 during every 92-minute ISS rotation. X-ray transients are quickly found by the real-time nova-search program. As a result, MAXI has issued 133 Astronomer's Telegrams and 44 Gamma-ray burst Coordinated Networks so far. MAXI has discovered six new black holes (BH) in 4.5 years. Long-term behaviors of the MAXI BHs can be classified into two types by their outbursts; a fast-rise exponential-decay type and a fast-rise flat-top one. The slit camera is suitable for accumulating data over a long time. MAXI issued a 37-month catalog containing 500 sources above a ~0.6 mCrab detection limit at 4-10 keV in the region ${\mid}{b}{\mid}$ > $10^{\circ}$. The SSC instrument utilizing an X-ray CCD has detected diffuse soft X-rays extending over a large solid angle, such as the Cygnus super bubble. MAXI/SSC has also detcted a Ne emission line from the rapid soft X-ray nova MAXI J0158-744. The overall shapes of outbursts in Be X-ray binaries (BeXRB) are precisely observed with MAXI/GSC. BeXRB have two kinds of outbursts, a normal outburst and a giant one. The peak dates of the subsequent giant outbursts of A0535+26 repeated with a different period than the orbital one. The Be stellar disk is considered to either have a precession motion or a distorted shape. The long-term behaviors of low-mass X-ray binaries (LMXB) containing weakly magnetized neutron stars are investigated. Transient LMXBs (Aql X-1 and 4U 1608-52) repeated outbursts every 200-1000 days, which is understood by the limit-cycle of hydrogen ionization states in the outer accretion disk. A third state (very dim state) in Aql X-1 and 4U 1608-52 was interpreted as the propeller effect in the unified picture of LMXB. Cir X-1 is a peculiar source in the sense that its long-term behavior is not like typical LMXBs. The luminosity sometimes decreases suddenly at periastron. It might be explained by the stripping of the outer accretion disk by a clumpy stellar wind. MAXI observed 64 large flares from 22 active stars (RS CVns, dMe stars, Argol types, young stellar objects) over 4 years. The total energies are $10^{34}-10^{36}$ erg $s^{-1}$. Since MAXI can measure the spectrum (temperature and emission measure), we can estimate the size of the plasma and the magnetic fields. The size sometimes exceeds the size of the star. The magnetic field is in the range of 10-100 gauss, which is a typical value for solar flares.