• Progress in Medical Physics
• /
• v.15 no.1
• /
• pp.30-38
• /
• 2004

Purpose: To develop a whole body frame for the purpose of reducing patient motion and minimizing setup error for extra-cranial stereotactic radiotherapy, and to evaluate the repositioning setup error of a patient in the frame. Materials and Methods: The developed whole body frame is composed of a base plate, immobilizer, vacuum cushion, ruler and belts. The dimension of the base plate is 130 cm in length, 50 cm in width and 1 cm in thickness. The material used in the base plate of the frame was bakelite and the immobilizer was made of acetal. In addition, Radiopaque angio-catheter wires were engraved on the base plate for a coordinate system to determine the target localization. The measurement for radiation transmission and target localization is peformed in order to test the utilization of the frame. Also, a Matlab program analyzed the patients setup error by using the patient's setup images obtained from a CCTV camera and digital record recorder (DVR). Results: A frame that is useful for CT simulation and radiation treatment was fabricated. The frame structure was designed to minimize collisions from the changes in the rotation angle of the gantry and to maximize the transmission rate of the Incident radiation at the lateral or posterior oblique direction. The lightening belts may be used for the further reduction of the patient motion, and the belts can be adjusted so that they are not in the way of beam direction. The radiation transmission rates of this frame were measured as 95% and 96% at 10 and 21 MV, respectively. The position of a test target on the skin of a volunteer is accurately determined by CT simulation using the coordinate system in the frame. The estimated setup errors by Matlab program are shown 3.69$\pm$1.60, 2.14$\pm$0.78 mm at the lateral and central chest, and 7.11 $\pm$2.10, 6.54$\pm$2.22 mm at lateral and central abdomen, respectively. The setup error due to the lateral motion of breast is shown as 6.33$\pm$ 1.55 mm. Conclusion: The development and test of a whole body frame has proven very useful and practical in the radiosurgery for extra-cranial cancers. It may be used in determining target localization, and it can be used as a patient immobilization tool. More experimental data should be obtained in order to improve and confirm the results of the patient setup error.

• Progress in Medical Physics
• /
• v.26 no.4
• /
• pp.250-257
• /
• 2015

Multi-leaf collimator (MLC) systems are frequently used to deliver photon-based radiation, and allow conformal shaping of treatment beams. Many proton beam centers currently make use of aperture and snout systems, which involve use of a snout to shape and focus the proton beam, a brass aperture to modify field shape, and an acrylic compensator to modulate depth. However, it needs a lot of time and cost of preparing treatment, therefore, we developed the manual MLC for solving this problem. This study was carried out with the intent of designing an MLC system as an alternative to an aperture block system. Radio-activation and dose due to primary proton beam leakage and the presence of secondary neutrons were taken into account during these iterations. Analytical calculations were used to study the effects of leaf material on activation. We have fabricated tray model for adoption with a wobbling snout ($30{\times}40cm^2$) system which used uniform scanning beam. We designed the manual MLC and tray and can reduce the cost and time for treatment. After leakage test of new tray, we upgrade the tray with brass and made the safety tool. First, we have tested the radio-activation with usually brass and new brass for new manual MLC. It shows similar behavior and decay trend. In addition, we have measured the leakage test of a gantry with new tray and MLC tray, while we exposed the high energy with full modulation process on film dosimetry. The radiation leakage is less than 1%. From these results, we have developed the design of the tray and upgrade for safety. Through the radio-activation behavior, we figure out the proton beam leakage level of safety, where there detects the secondary particle, including neutron. After developing new design of the tray, it will be able to reduce the time and cost of proton treatment. Finally, we have applied in clinic test with original brass aperture and manual MLC and calculated the gamma index, 99.74% between them.

• Journal of Chest Surgery
• /
• v.43 no.5
• /
• pp.482-489
• /
• 2010

Background: The purpose of this study was to determine whether hand-measured carotid intima-media thickness (IMT) was a reliable and simple tool that could be used to evaluate the severity of stable coronary artery disease (CAD) with normal high-sensitivity C-reactive protein (CRP). Material and Method: We examined left carotid IMTs in 688 patients with stable CAD and excluded 121 patients with abnormally elevated hs-CRP ($\geq$0.5 mg/dL). We sought to determine the association between risk factors and the severity of stable CAD and carotid IMT in 567 patients who were divided into lower and higher groups based on the median value. Patients underwent a coronary artery angiogram and had at least significant stenosis (>50% of the original luminal diameter involving one or more major coronary artery). Result: Of the 567 patients, 300 (52.9%) were in the lower IMT group and 267 (47.1%) were in the higher IMT group; the median value was 0.76 mm. By multivariable logistic regression analysis, the following groups were different: older age (~49 vs. 70~ years, respectively; OR=6.552), high FBS (~99 vs. 120~ mg/dL; OR=1.713) and severity of CAD (1 vessel vs. 2 vessel disease; OR=1.711, 1 vessel vs. 3 vessel disease; OR=1.714). Conclusion: We conclude that there are correlations between increased carotid IMT and severity of CAD in stable angina patients with normal CRP levels.

• Journal of the Korean association of regional geographers
• /
• v.6 no.3
• /
• pp.117-138
• /
• 2000

This study is, from the view point of constructive social studies which is the foundation of the 7th curriculum, to explore whether there is any viable program and to investigate it by which students, using photo resources in social studies, can organize their knowledge in the way of self-directed thinking. The main results are as follows: If it is a principle of knowledge construction process of constructive social studies that individual construction (cognitive construction) develops into communal construction(social construction) and yet communal construction develops itself, interacting with individual construction, it will be meet the objectives of social studies. In social studies, photos are a powerful communication tool. communicating with photos enables to invoke not only the visual aspects but also invisible aspects of social phenomena from photos. It, therefore, can help develop thinking power through inquiry learning, which is one of the emphasis of the 7th curriculum. Having analyzed photo resources appeared on the regional textbooks in elementary social studies, they have been appeared that even though the importance and amount of space photo resources occupy per page is big with regard to total resources, most of the photos failed to lad to self-directed thinking but just assistant material in stead. Besides, there appeared some problems with the title, variety, size, position, tone of color, visibility of the photos, and further with the combination of the photos. Developing of photo resources for constructive social studies is to overcome some problems inherent in current text books and to reflect the theoretical background of the 7th curriculum. To develop the sort of photo that can realize the point just mentioned, it would be highly preferable to provide photo database to facilitate study with homepage through web-based interaction. To take advantage of constructive photo resources, the instruction is strategized in four stages, intuition, conflict, accommodation, and equilibration stage. With the advancement of the era of image culture, curriculum developers are required to develop dynamic, multidimensional digital photos rather than static photos when develop text books.

• Journal of Chest Surgery
• /
• v.35 no.3
• /
• pp.171-176
• /
• 2002

Background: Blood-foreign interaction cause activation of coagulation and inflammatory process that may lead to multiorgan dysfunction and determine the surgical outcomes. Of the methods for assessing the biocompatibility, the platelet adhesion study is considered as the most valuable evaluation step in blood-foreign interaction. As the most studies have used in-vitro or ex-vivo conditions, we have developed a technique of quantification for platelet adhesion on the blood contact surface by using in-vivo injection of radioactive platelets. Material and Method: A coupled bypass circuit was designed to connect the proximal and descending thoracic aorta in 6 piglets(20∼25 Kg). One side of the circuit tube was consisted of a heparin coated PVC tube(10mm in ID, n=6, Experimental group), and the other, a non-heparin coated PVC tube(10mm in ID, n=6, Control group). After cannulation, the blood was circulated through the circuit for 2 hours. Platelet concentrate was prepared from homologous pig blood 24 hours before the experiment. The platelet concentrate was incubated with Tc-99m-HMPAO for 30 min and then centrifuged for 10 min. The supernatant was discarded and the radio-labeling efficacy was measured. The radio-labeled platelet concentrate was mixed with the autologous plasma to make the volume 5 ml, and the mixture was injected intravenously into the experimental animal. After 2 hour circulation, 5 pieces of the specimen(10mm in length each) were obtained from each PVC tube. The radioisotopes were counted with a gamma counter(Cobra ll, Packard, USA), and the ratio of radioisotope count was compared between the control and experimental group. Result: The radioisotope count number was 537.3221.1 Ci/min in the control group and 311.1 184.5 Ci/min in the experimental group(p=0.0104). The ratio between the groups was 1 to 0.58 (p=0.004). Conclusion: In vivo quantification using technetium-99m-HMPAO labeled platelets is simple and reproducible in evaluating platelet adhesion on a foreign surface. We suggest this technique to be a useful tool for blood compatibility test.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.44 no.11
• /
• pp.1741-1749
• /
• 2015

The purpose of this study was to investigate parents' perception and satisfaction of school food materials and supplier performance in Mokpo. To achieve these research objectives, a questionnaire was distributed to parents at 66 schools, and a total of 589 were used in the final analysis. The results of this study were as follows. First, satisfaction of school foodservice, showed the following scores: overall was 3.75, quality of food materials was 3.84, reliability of food suppliers was 3.80, education was 3.53, and information was 3.50. Second, 38.5% of parents participated in receiving school materials. Exactly 80.6% of parents showed intentions to participate. The most difficult thing for receiving materials was comparing quality of food materials (46.3%). Third, the most important factor cited for school food supplier was quality (62.3%) and sanitation and safety (24.1%). Forth, most parents were positive about the possibility of replacing foods used at school with environment friendly products. Local foods were cited for use in school foodservice (92.2%). The reasons were good quality (39.9%) and contribution to the local community (28.5%). In conclusion, parent's perception of school foodservice should increase to improve food material quality of school foodservice. Institutions for certifying are needed to offer high quality food materials at school foodservice and improved communication and education tool between the school and parents.

• The Journal of Korean Academy of Prosthodontics
• /
• v.46 no.2
• /
• pp.169-174
• /
• 2008

Statement of problem: Changes of the marginal bone around dental implants have significance not only for the functional maintenance but also for the esthetic success of the implant. It was proposed that bone-retention elements such as microthreads at the coronal part of implant might help maintain the marginal bone level. Purpose: This study was designed to evaluate the effect of microthread configuration within the marginal coronal portion of the implant fixture at the marginal bone changes after loading around two different external hex implants. Material and methods: Twenty-four patients were included and randomly assigned to treatment with $Br{{\aa}}nemark$ system implants (Group 1, rough-surfaced implants, n=20) and Oneplant system implants (Group 2, rough-surfaced neck with microthreads, n=20). Clinical and radiographic examinations were conducted at baseline (implant loading) and 1 year postloading. Data analysis was performed by the SAS statistical package version 9.1.3 (SAS Institute, Cary, NC, USA) and the final model was calculated by the MIXED procedure (three-level ANCOVA) for marginal bone change of each test group at baseline and 1 year follow-up. Results: Comparing to baseline, significant differences were noted in marginal bone level changes for the 2 groups at 1 year follow-up (P<0.05). Group 1 had a mean crestal bone level changes of $0.83{\pm}0.31mm$; Group 2 had a mean crestal bone level changes of $0.44{\pm}0.36mm$. Rough-surfaced with microthreads implants showed significantly less marginal bone loss than rough surfaced neck without microthread implants. Conclusion: A rough surface with microthreads at the implant was beneficial design to maintain the marginal bone level against functional loading.

• Journal of Korean Society of Environmental Engineers
• /
• v.32 no.4
• /
• pp.341-348
• /
• 2010

The basic principle of fry drying process of sludge lies in the rapid pressure change of sludge material caused by the change of temperature between oil and moisture due to the difference of specific heat. Therefore, the rapid increase of pressure in drying sludge induces the efficient moisture escape through sludge pores toward heating oil media. The object of this study is to carry out a systematic investigation of the influence of various parameters associated with the sludge fry drying processes on the drying efficiency. To this end, a series of parametric experimental investigation has been made together with the numerical calculation in order to obtain typical drying curves as function of important parameters such as drying temperature, sludge diameter, oil type and sludge type. In the aspect of frying temperature, especially it is found that the operation higher than $140^{\circ}C$ was favorable in drying efficiency regardless of type of waste oil employed in this study. The same result was also noted consistently in the investigation of numerical calculation, that is, in that the sludge particle drying was efficiently made over $140^{\circ}C$ irrespective of the change of particle diameter. As expected, in general, the decrease of diameter in sludge was found efficient both experiment and numerical calculation in drying due to the increased surface area per unit volume. In the investigation of oil type and property, the effect of the viscosity of waste oil was found to be more influential in drying performance. In particular, when the oil with high viscosity, a visible time delay was noticed in moisture evaporation especially in the early stage of drying. However, the effect of high viscosity decreased significantly over the temperature of $140^{\circ}C$. There was no visible difference observed in the study of sludge type but the sewage sludge with a slightly better efficiency. The numerical study is considered to be a quite useful tool to assist in experiment with more detailed empirical modeling as further work.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
• /
• 2000.06a
• /
• pp.16-23
• /
• 2000

The increasing functional needs of top-quality printing papers and packaging paperboards, and especially the rapid developments in electronic printing processes and various computer printers during past few years, set new targets and requirements for modern paper quality. Most of these paper grades of today have relatively high filler content, are moderately or heavily calendered , and have many coating layers for the best appearance and performance. In practice, this means that many of the traditional quality assurance methods, mostly designed to measure papers made of pure. native pulp only, can not reliably (or at all) be used to analyze or rank the quality of modern papers. Hence, introduction of new measurement techniques is necessary to assure and further develop the paper quality today and in the future. Paper formation , i.e. small scale (millimeter scale) variation of basis weight, is the most important quality parameter of paper-making due to its influence on practically all the other quality properties of paper. The ideal paper would be completely uniform so that the basis weight of each small point (area) measured would be the same. In practice, of course, this is not possible because there always exists relatively large local variations in paper. However, these small scale basis weight variations are the major reason for many other quality problems, including calender blacking uneven coating result, uneven printing result, etc. The traditionally used visual inspection or optical measurement of the paper does not give us a reliable understanding of the material variations in the paper because in modern paper making process the optical behavior of paper is strongly affected by using e.g. fillers, dye or coating colors. Futhermore, the opacity (optical density) of the paper is changed at different process stages like wet pressing and calendering. The greatest advantage of using beta transmission method to measure paper formation is that it can be very reliably calibrated to measure true basis weight variation of all kinds of paper and board, independently on sample basis weight or paper grade. This gives us the possibility to measure, compare and judge papers made of different raw materials, different color, or even to measure heavily calendered, coated or printed papers. Scientific research of paper physics has shown that the orientation of the top layer (paper surface) fibers of the sheet paly the key role in paper curling and cockling , causing the typical practical problems (paper jam) with modern fax and copy machines, electronic printing , etc. On the other hand, the fiber orientation at the surface and middle layer of the sheet controls the bending stiffness of paperboard . Therefore, a reliable measurement of paper surface fiber orientation gives us a magnificent tool to investigate and predict paper curling and coclking tendency, and provides the necessary information to finetune, the manufacturing process for optimum quality. many papers, especially heavily calendered and coated grades, do resist liquid and gas penetration very much, bing beyond the measurement range of the traditional instruments or resulting invonveniently long measuring time per sample . The increased surface hardness and use of filler minerals and mechanical pulp make a reliable, nonleaking sample contact to the measurement head a challenge of its own. Paper surface coating causes, as expected, a layer which has completely different permeability characteristics compared to the other layer of the sheet. The latest developments in sensor technologies have made it possible to reliably measure gas flow in well controlled conditions, allowing us to investigate the gas penetration of open structures, such as cigarette paper, tissue or sack paper, and in the low permeability range analyze even fully greaseproof papers, silicon papers, heavily coated papers and boards or even detect defects in barrier coatings ! Even nitrogen or helium may be used as the gas, giving us completely new possibilities to rank the products or to find correlation to critical process or converting parameters. All the modern paper machines include many on-line measuring instruments which are used to give the necessary information for automatic process control systems. hence, the reliability of this information obtained from different sensors is vital for good optimizing and process stability. If any of these on-line sensors do not operate perfectly ass planned (having even small measurement error or malfunction ), the process control will set the machine to operate away from the optimum , resulting loss of profit or eventual problems in quality or runnability. To assure optimum operation of the paper machines, a novel quality assurance policy for the on-line measurements has been developed, including control procedures utilizing traceable, accredited standards for the best reliability and performance.

• Journal of Chest Surgery
• /
• v.42 no.6
• /
• pp.738-743
• /
• 2009

Background: There is no standardized tool and parameter that can accurately assess the sympathetic function before and after performing sympathectomy in patients with primary palmar hyperhidrosis. We examined the effective-ness of the sympathetic skin response (SSR) study for documenting the change of sympathetic denervation before and after performing selective thoracic sympathicotomy. Material and Method: We prospectively investigated the SSR from 12 healthy subjects who were diagnosed with primary hyperhidrosis. Each SSR was recorded on the right palm or sole with electrical stimuli applied to the skin at the left wrist and foot and vice versa for the controlateral side. This test was performed before, 2 weeks and 1 year after selective thoracic sympathicotomy. The data was corrected for the onset latency and the amplitude of the SSR (n=24). Result: The mean age of the 12 patients was $24.6{\pm}0.4$ years (range: 19~36) and the gender ratio was 1 : 0.7. The mean values of the preoperative, postoperative 2 weeks and postoperative 1 year onset latency and amplitude of the palmar side (n=24) were $1.46{\pm}0.24$ msec and $6,043{\pm}2,339{\mu}V$, $1.63{\pm}0.42$ msec and $823{\pm}638{\mu}V$, and $1.44{\pm}0.39$ msec and $2,412{\pm}1,546{\mu}V$, respectively. The mean values of the plantar side (n=38) were $1.83{\pm}0.42$ msec and $2,816{\pm}1,694{\mu}V$, $2.16{\pm}0.39$ msec and $1,445{\pm}1,281{\mu}V$ and $1.95{\pm}0.25$ msec and $1,622{\pm}865{\mu}V$, respectively. Among the documented parameters, only the palmar amplitude (p=0.002) showed statistical significance in recording the change of the sympathetic system within the same individual for the pre and postoperative period. Conclusion: The SSR amplitude ratio may be a useful parameter for documenting the efficacy of sympathetic denervation after selective sympathicotomy.