• Progress in Medical Physics
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• v.23 no.1
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• pp.8-14
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• 2012

In order to develop a Patient respiratory management system includinga biofeedback function for4-dimentional radiation therapy, this study investigated anoptimal tracking algorithmfor moving target using IR (Infra-red) camera as well as commercial camera. A tracking system was developed by LabVIEW 2010. Motion phantom images were acquired using a camera (IR or commercial). After image process were conducted to convert acquired image to binary image by applying a threshold values, several edge enhance methods such as Sobel, Prewitt, Differentiation, Sigma, Gradient, Roberts, were applied. The targetpattern was defined in the images, and acquired image from a moving targetwas tracked by matching pre-defined tracking pattern. During the matching of imagee, thecoordinateof tracking point was recorded. In order to assess the performance of tracking algorithm, the value of score which represents theaccuracy of pattern matching was defined. To compare the algorithm objectively, we repeat experiments 3 times for 5 minuts for each algorithm. Average valueand standard deviations (SD) of score were automatically calculatedsaved as ASCII format. Score of threshold only was 706, and standard deviation was 84. The value of average and SD for other algorithms which combined edge detection method and thresholdwere 794, 64 in Sobel, 770, 101 in Differentiation, 754, 85 in Gradient, 763, 75 in Prewitt, 777, 93 in Roberts, and 822, 62 in Sigma, respectively. According to score analysis, the most efficient tracking algorithm is the Sigma method. Therefore, 4-dimentional radiation threapy is expected tobemore efficient if threshold and Sigma edge detection method are used together in target tracking.

• Progress in Medical Physics
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• v.24 no.1
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• pp.25-34
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• 2013

To investigate effects of phase mask on susceptibility-weighted images (SWI) using voxel-based analyses in normal elderly subjects. A three-dimensional (3D) gradient echo sequence ran to obtain SWIs in 20 healthy elderly subjects. SWIs with two (SWI2) and four (SWI4) phase multiplications were achieved with positive (PSWI) and negative (NSWI) phase masks to investigate phase mask effects. The voxel-based comparisons were performed using paired t-tests between PSWI and NSWI and between SWI2 and SWI4. Differences of signal intensities between magnitude images and SWI4 were larger than those between magnitude images and SWI2s. Differences of signal intensities between magnitude images and PSWIs were larger than those between magnitude images and NSWIs. Moreover, the signal intensities from NSWI2s and NSWI4s were greater than those from PSWI2s and PSWI4s, respectively. More differences of signal intensities between NSWI4 and PSWI4s were found than those between NSWI2s and PSWI2s in the whole brain images. The voxel-based analyses of SWI could be beneficial to investigate susceptibility differences on the entire brain areas. The phase masking method could be chosen to enhance brain tissue contrast rather than to enhance venous blood vessels. Therefore, it is recommended to apply voxel-based analyses of SWI to investigate clinical applications.

• Journal of Biomedical Engineering Research
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• v.23 no.2
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• pp.147-153
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• 2002

The purpose of this study was to evacuate the effect of different types of Poly(lactic-co-glycolic acid) (PLGA) scaffolds on the formation of human auricular and septal cartilages. All of the scaffolds were formed in a tubular shape for potential application for artificial trachea or esophagus with either 110,000 g/mol PLGA. 220,000 g/mol PLGA. or a combination of both. In order to maintain the tubular shape in vivo, two methods were used. One method was inserting polyethylene tube at the center of scaffolds made of 110,000 g/mol PLGA. The other method involved combination of the two different molecular weight PLGA's. The inner surface of tubular shaped scaffold made with 110,000 g/mol PLGA was coated with 220,000 9/mol PLGA to give more mechanical rigidity. Elastic cartilage was taken from the ear of a patient aged under 20 nears old and hyaline cartilage was taken from the nasal septum. The chondrocytes were then isolated. After second passage, the chondrocytes were seeded on the PLGA scaffolds followed by in vitro culture for one week. The cells-PLGA scaffold complex were implanted subcutaneously on the back of nude mice for 8 weeks. The tissue engineered cartilages were separated from nude mice and examined histologically after staining with the Hematoxylin Eosin. The morphology of the scaffolds were examined by scanning electron microscopy. The pores were well formed and uniformly distributed in the various PLGA scaffolds. After 8 weeks in vivo culture, cartilage was well formed with 110,000 g/mol PLGA. however lumen had collapsed. In contrast. a minimal amount of neocartilage was formed with 220,000 g/mol PLGA, while the architecture of scaffold and lumen were well preserved. Elastic cartilage formed more neocartilage than hyaline. Hyaline and elastic neocartilage were well formed on 110,000 g/mol PLGA with the polyethylene tube, exhibiting mature chondrocytes and preservation of the tubular shape. It was found that 110,000 g/mol PLGA was more appropriate for cartilage formation but higher molecular weight polymer was necessary to maintain the three dimensional shape of the scaffold.

• Journal of Biomedical Engineering Research
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• v.25 no.2
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• pp.157-163
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• 2004

Nitrogen ion implantation and ion plating techniques were applied for improvement of the wear resistance of metallic implant materials. In this work, the wear dissolution behaviour of a nitrogen ion implanted super stainless steel (S.S.S, 22Cr-20Ni-6Mo-0.25N) was compared with those of S.S.S, 316L SS and TiN coated 316L SS. The amounts of Cr and Ni ions worn-out from the specimens were Investigated using an electrothermal atomic absorption spectrometry. Furthermore, the Ti(Grade 2) disks were coated with TiN, ZrN and TiCN by use of low temperature arc vapor deposition and the wear resistance of the coating layers was compared with that of titanium. The chemical compositions of the nitrogen ion implanted and nitride coated layers were examined with a scanting auger electron spectroscopy. It wat observed that the metal ions released from the nitrogen ion implanted S.S.S surface were significantly reduced. From the results obtained, it was shown that the nitrogen ion implanted zone obtained with 100 KeV ion energy was easily removed within 200,000 revolutions from a wear dissolution testing under a similar load condition when applied to artificial hip joint. The remarkable improvement in wear resistance weir confirmed by the nitrides coated Ti materials and the wear properties differ greatly according to the chemical composition of the coating layers. for specimens with the same coating thickness of about 3$\mu\textrm{m}$, TiCN coated Ti showed the highest wear resistance. However, after removing the coating layers, the wear rates of all nitrides coated Ti reverted to their normal rates of below 10,000 revolutions from Ti-disk-on-disk wear testing under the same load condition. From the results obtained, it is suggested that the insufficient depth of the 100 Kel N$\^$＋/ ion implanted zone and of the nitrides coated layers of 3$\mu\textrm{m}$ are subject to restriction when used as frictional parts of load bearing implants.

• Journal of Biomedical Engineering Research
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• v.31 no.4
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• pp.280-284
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• 2010

Approvals of medical device increase every year as industry of medical device grows. Therefore KFDA keeps trying to improve approval systems. However, the firms of medical device are in trouble due to regulation amendment, a firm of small size, exchange of the person in charge. The staffs of KFDA increase their work load because applicants of approval of medical device aren't used to writing of document. Therefore the firm of medical device in business have a long term. KFDA develops eight guidance document item by item for one-step evaluation and approval for Medical Devices because applicants of approval of medical device write documents easily. KFDA reviewer can carry on quick reviewing in use of this eight guidances. This guidance are improved on satisfaction of applicants of approval of medical device.

• The Korean Journal of Nuclear Medicine
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• v.32 no.3
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• pp.238-249
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• 1998

Purpose: To localize and compare the neural basis of verbal and visual human working memory, we performed functional activation study using $H_2^{15}O$ PET. Materials and Methods: Repeated $H_2^{15}O$ PET scans with one control and three different activation tasks were performed on six right-handed normal volunteers. Each activation task was composed of 13 match-ing trials. On each trial, four targets, a fixation dot and a probe were presented sequentially and subject's task was to press a response button to indicate whether or not the probe was one of the previous targets. Short meaningful Korean words, simple drawings and monochromic pictures of human faces were used as matching objects for verbal or visual memory. All the images were spatially normalized and the differences between control and activation states were statistically analyzed using SPM96. Results: Statistical analysis of verbal memory activation with short words showed activation in the left Broca's area, promoter cortex, cerebellum and right cingulate gyrus. In verbal memory with simple drawings, activation was shown in the larger regions including where activated with short words and left superior temporal cortex, basal ganglia, thalamus, prefrontal cortex, anterior portion of right superior temporal gyrus and right infero-lateral frontal cortex. On the other hand, the visual memory task activated predominantly right-sided structures, especially inferior frontal cortex, supplementary motor cortex and superior parietal cortex. Conclusion: The results are consistent with the hypothesis of the laterality and dissociation of the verbal and visual working memory from the invasive electrophysiological studies and emphasize the pivotal role of frontal cortex and cingulate gyrus in working memory system.

• Journal of Food Hygiene and Safety
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• v.27 no.1
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• pp.81-86
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• 2012

The present study was evaluated the antibacterial effect of the combination of $Coptidis$ $rhizoma$, $Glycyrrhiza$ $uralensis$ Fischet, $Schizandra$ $chinensis$ and $Corni$ $Fructus$(1:1:1) extracts(CGSC10). Furthermore, the effectiveness of CGSC10, sodium chlorate, and the combination of CGSC10 and sodium chlorate(CGSCS10) against $E.$ $coli$ O157:H7 infection was studied using ICR female mice. During the incubation period, the dose of 5, 10, and 20% CGSC10 was inhibited the growth of $E.$ $coli$ O157:H7 by 34.7, 60.2, and 76.4%, respectively. For 7 days after single challenge with $E.$ $coli$ O157:H7, forty female ICR mice were divided into four experimental groups which were administered in drinking water with saline, 10% CGSC10, 15 mM sodium chlorate, and CGSCS10, respectively. On the 3rd day, the number of $E.$ $coli$ O157:H7 in mouse feces was significantly decreased by administration of CGSC10, 15 mM sodium chlorate, and CGSCS10 ($p$ < 0.001). On the 7th day-after administration, CGSC10, sodium chlorate, and CGSCS10 were decreased the number of $E.$ $coli$ O157:H7 by 27.1, 67.7, and 83.3%, respectively. According to the results of the present study, administration of CGSCS10 to mice can reduce the severity of $E.$ $coli$ O157:H7 infection. In addition, it is suggested that CGSCS10 represents a good candidate for the treatment of enteric infections in domestic animals.

• Journal of Biomedical Engineering Research
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• v.24 no.5
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• pp.401-410
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• 2003

This study investigates the biomechanical efficacies of various cement augmentation techniques with or without pressurization for varying degrees of osteoporotic femur. For this study, a biomechanical analysis using a finite element method (FEM) was undertaken to evaluate surgical procedures, Simulated models include the non-cemented(i.e., hip screw only, Type I), the cement-augmented(Type II), and the cemented augmented with pressurization(Type III) models. To simulate the fracture plane and other interfacial regions, 3-D contact elements were used with appropriate friction coefficients. Material properties of the cancellous bone were varied to accommodate varying degrees of osteoporosis(Singh indices, II∼V). For each model. the following items were analyzed to investigate the effect surgical procedures in relation to osteoporosis of varying degrees : (a) von Mises stress distribution within the femoral head in terms of volumetric percentages. (b) Peak von Mises stress(PVMS) within the femoral head and the surgical constructs. (c) Maximum von Mises strain(MVMS) within the femoral head, (d) micromotions at the fracture plane and at the interfacial region between surgical construct and surrounding bone. Type III showed the lowest PVMS and MVMS at the cancellous bone near the bone-construct interface regardless of bone densities. an indication of its least likelihood of construct loosening due to failure of the host bone. Particularly, its efficacy was more prominent when the bone density level was low. Micromotions at the interfacial surgical construct was lowest in Type III. followed by Type I and Type II. They were about 15-20% of other types. which suggested that pressurization was most effective in limiting the interfacial motion. Our results demonstrated the cement augmentation with hip screw could be more effective when used with pressurization technique for the treatment of intertrochanteric fractures. For patients with low bone density. its effectiveness can be more pronounced in limiting construct loosening and promoting bone union.

• Journal of Biomedical Engineering Research
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• v.19 no.3
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• pp.279-284
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• 1998

Deep hypothermic circulatory arrest(DHCA), in which systemic temperatures of 2$0^{\circ}C$ or less are used to allow temporary cessation of the circulation, is an useful adjunct in cardiac surgery. Because man in natural circumstances is never exposed to the extreme hypothermic condition, however, one of the controversial aspects is appropriate blood gas management($\alpha$STAT versus PH-STAT) during DHCA. This study aims to compare $\alpha$STAT with PH-STAT management for control of blood gases in experimental cardiopulmonary bypass(CPB) circuits with a membrane oxygenator. Fourteen young pigs were assigned to one of two strategies of gas manipulation. After a median sternotomy, CPB was established. Core cooling was initiated and continued until nasopharyngeal temperature fell below 2$0^{\circ}C$. The flow rate was set at 2,500 ml/min. Once their temperatures were below 2$0^{\circ}C$, the animals were subjected to circulatory arrest for 40mins. During cooling, blood gas was maintained according to either $\alpha$$\alpha$STAT or pH-STAT strategies. After DHCA, the body was rewarmed to normal body temperature. Arterial blood gases were measured before the onset of CPB, before cooling, before DHCA, at the point of 27$^{\circ}C$ during re-warming, on completion of re-warming. Cooling time was significantly shorter in $\alpha$-STAT than PH-STAT strategy, while there was no significant differences in rewarming time between two groups. Carbon dioxide was added between 5.5 and 3.0% in PH-STAT, while no carbon dioxide was added in $\alpha$STAT management. Amounts of oxygen administration were gradually lowered as temperature decreased. In this way, criteria of PH, PaCO, and PaO adjustments were satisfied in both $\alpha$STAT and PH-STAT management groups.

• Journal of Food Hygiene and Safety
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• v.28 no.4
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• pp.349-353
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• 2013

This study was performed to evaluate the bactericidal efficacy of Fumagari OPP$^{(R)}$, fumigation disinfectant, containing 20% ortho-phenylphenol against Staphylococcus aureus (S. aureus). In this research, efficacy test of fumigant against S. aureus was carried out according to French standard NF T 72-281. S. aureus working culture suspension number (N value), all of the colony numbers on the carriers exposed with the fumigant (n1, n2, and n3), the number of bacterial test suspentions by pour plate method (N1), the number of bacterial test suspentions by filter membrane method (N2) and the mean number of bacteria recovered on the control-carriers (T value) were obtained from the preliminary test. In addition, the reduction number of S. aureus exposed with the fumigant (d value) was calculated using T value, the mean number of bacteria in recovery solution (n'1) and the mean number of bacteria on carriers plated in agar (n'2). N value was $4.0{\times}10^8$ CFU/mL, and n1, n2, and n3 were higher than 0.5N1, 0.5N2 and 0.5N1, respectively. Additionally, T value was $3.4{\times}10^6$ CFU/mL. In the bactericidal effect of the fumigant, the d value was 6.43 logCFU/mL. According to the French standard for the fumigant, the d value for the effective bactericidal fumigant should be over than 5 logCFU/mL. The results indicated that Fumagari OPP$^{(R)}$ had an effective bactericidal activity against S. aureus, then the fumigant can be applied to disinfect food materials and kitchen appliances contaminated with pathogenic bacteria.