• Title/Summary/Keyword: digital control

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Using CR System at the Department of Radiation Oncology PACS Evaluation (방사선 종양학과에서 CR System을 이용한 PACS 유용성 평가)

  • Hong, Seung-Il;Kim, Young-Jae
    • Journal of the Korean Society of Radiology
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    • v.6 no.2
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    • pp.143-149
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    • 2012
  • Today each hospital is trend that change rapidly by up to date, digitization and introducing newest medical treatment equipment. So, we introduce new CR system and supplement film system's shortcoming and PACS, EMR, RTP system's network that is using in hospital harmoniously and accomplish quality improvement of medical treatment and service elevation about business efficiency enlargement and patient Accordingly, we wish to introduce our case that integrate reflex that happen with radiation oncology here upon to PACS using CR system and estimate the availability. We measured that is Gantry, Collimator Star Shot, Light vs. Radiation, HDR QA(Dwell position accuracy) with Medical LINAC(MEVATRON-MX) Then, PACS was implemented on the digital images on the monitor that can be confirmed through the QA. Also, for cooperation with OCS system that is using from present source and impose code that need in treatment in each treatment, did so that Order that connect to network, input to CR may appear, did so that can solve support data mistake (active Pinacle's case supports DICOM3 file from present source but PACS does not support DICOM3 files.) of Pinacle and PACS that is Planning System and look at Planning premier in PACS. All image and data constructed integration to PACS as can refer and conduct premier in Hospital anywhere using CR system. Use Dosimetry IP in Filmless environment and QA's trial such as Light/Radition field size correspondence, gantry rotation axis' accuracy, collimator rotation axis' accuracy, brachy therapy's Dwell position check is available. Business efficiency by decrease and so on of unnecessary human strength consumption was augmented accordingly with session shortening as that integrate premier that is neted with radiation oncology using CR system to PACS. and for the future patient information security is essential.

Alterations of Cerebral Blood Flow and Cerebrovascular Reserve in Patients with Chronic Traumatic Brain Injury Accompanying Deteriorated Intelligence (지능 저하를 동반한 두부외상 환자에서 뇌혈류 및 혈류예비능의 변화)

  • Song, Ho-Chun;Bom, Hee-Seung
    • The Korean Journal of Nuclear Medicine
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    • v.34 no.3
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    • pp.183-198
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    • 2000
  • Purpose: The purpose of this study was to evaluate alterations of regional cerebral blood flow (CBF) and cerebrovascular reserve (CVR), and correlation between these alternations and cognitive dysfunction in patients with chronic traumatic brain injury (TBI) and normal brain MRI findings. Materials and Methods: Thirty TBI patients and 19 healthy volunteers underwent rest/acetazolamide brain SPECT using Tc-99m HMPAO. Korean-Wechsler Adult Intelligence scale test was also performed in the patient group. Statistical analysis was performed with statistical parametric mapping software (SPM'97) Results: CBF was diminished in the left hemisphere including Wernicke's area in all patients with lower verbal scale scores. In addition, a reduction in CBF in the right frontal, temporal and parietal cortices was related with depressed scores in information, digital span, arithmetic and similarities. In patients with lower performance scale scores, CBF was mainly diminished in the right hemisphere including superior temporal and supramarginal gyri, premotor, primary somatomotor and a part of prefrontal cortices, left frontal lobe and supramarginal gyrus. CVR was diminished in sixty-four Brodmann's areas compared to control. A reduction in CVR was demonstrated bilaterally in the frontal and temporal lobes in patients with lower scores in both verbal and performance tests, and in addition, both inferior parietal and occipital lobes in information subset. Conclusion: Alterations of CBF and CVR were demonstrated in the symptomatic TBI patients with normal MRI finding. These alterations were correlated with the change of intelligence, of which the complex functions are subserved by multiple interconnected cortical structures.

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The Impact of Perceived Risks Upon Consumer Trust and Purchase Intentions (인지된 위험의 유형이 소비자 신뢰 및 온라인 구매의도에 미치는 영향)

  • Hong, Il-Yoo B.;Kim, Woo-Sung;Lim, Byung-Ha
    • Asia pacific journal of information systems
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    • v.21 no.4
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    • pp.1-25
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    • 2011
  • Internet-based commerce has undergone an explosive growth over the past decade as consumers today find it more economical as well as more convenient to shop online. Nevertheless, the shift in the common mode of shopping from offline to online commerce has caused consumers to have worries over such issues as private information leakage, online fraud, discrepancy in product quality and grade, unsuccessful delivery, and so forth, Numerous studies have been undertaken to examine the role of perceived risk as a chief barrier to online purchases and to understand the theoretical relationships among perceived risk, trust and purchase intentions, However, most studies focus on empirically investigating the effects of trust on perceived risk, with little attention devoted to the effects of perceived risk on trust, While the influence trust has on perceived risk is worth studying, the influence in the opposite direction is equally important, enabling insights into the potential of perceived risk as a prohibitor of trust, According to Pavlou (2003), the primary source of the perceived risk is either the technological uncertainty of the Internet environment or the behavioral uncertainty of the transaction partner. Due to such types of uncertainty, an increase in the worries over the perceived risk may negatively affect trust, For example, if a consumer who sends sensitive transaction data over Internet is concerned that his or her private information may leak out because of the lack of security, trust may decrease (Olivero and Lunt, 2004), By the same token, if the consumer feels that the online merchant has the potential to profit by behaving in an opportunistic manner taking advantage of the remote, impersonal nature of online commerce, then it is unlikely that the merchant will be trusted, That is, the more the probable danger is likely to occur, the less trust and the greater need to control the transaction (Olivero and Lunt, 2004), In summary, a review of the related studies indicates that while some researchers looked at the influence of overall perceived risk on trust level, not much attention has been given to the effects of different types of perceived risk, In this context the present research aims at addressing the need to study how trust is affected by different types of perceived risk, We classified perceived risk into six different types based on the literature, and empirically analyzed the impact of each type of perceived risk upon consumer trust in an online merchant and further its impact upon purchase intentions. To meet our research objectives, we developed a conceptual model depicting the nomological structure of the relationships among our research variables, and also formulated a total of seven hypotheses. The model and hypotheses were tested using an empirical analysis based on a questionnaire survey of 206 college students. The reliability was evaluated via Cronbach's alphas, the minimum of which was found to be 0.73, and therefore the questionnaire items are all deemed reliable. In addition, the results of confirmatory factor analysis (CFA) designed to check the validity of the measurement model indicate that the convergent, discriminate, and nomological validities of the model are all acceptable. The structural equation modeling analysis to test the hypotheses yielded the following results. Of the first six hypotheses (H1-1 through H1-6) designed to examine the relationships between each risk type and trust, three hypotheses including H1-1 (performance risk ${\rightarrow}$ trust), H1-2 (psychological risk ${\rightarrow}$ trust) and H1-5 (online payment risk ${\rightarrow}$ trust) were supported with path coefficients of -0.30, -0.27 and -0.16 respectively. Finally, H2 (trust ${\rightarrow}$ purchase intentions) was supported with relatively high path coefficients of 0.73. Results of the empirical study offer the following findings and implications. First. it was found that it was performance risk, psychological risk and online payment risk that have a statistically significant influence upon consumer trust in an online merchant. It implies that a consumer may find an online merchant untrustworthy if either the product quality or the product grade does not match his or her expectations. For that reason, online merchants including digital storefronts and e-marketplaces are suggested to pursue a strategy focusing on identifying the target customers and offering products that they feel best meet performance and psychological needs of those customers. Thus, they should do their best to make it widely known that their products are of as good quality and grade as those purchased from offline department stores. In addition, it may be inferred that today's online consumers remain concerned about the security of the online commerce environment due to the repeated occurrences of hacking or private information leakage. Online merchants should take steps to remove potential vulnerabilities and provide online notices to emphasize that their website is secure. Second, consumer's overall trust was found to have a statistically significant influence on purchase intentions. This finding, which is consistent with the results of numerous prior studies, suggests that increased sales will become a reality only with enhanced consumer trust.

Development of a Small Gamma Camera Using NaI(T1)-Position Sensitive Photomultiplier Tube for Breast Imaging (NaI (T1) 섬광결정과 위치민감형 광전자증배관을 이용한 유방암 진단용 소형 감마카메라 개발)

  • Kim, Jong-Ho;Choi, Yong;Kwon, Hong-Seong;Kim, Hee-Joung;Kim, Sang-Eun;Choe, Yearn-Seong;Lee, Kyung-Han;Kim, Moon-Hae;Joo, Koan-Sik;Kim, Byuug-Tae
    • The Korean Journal of Nuclear Medicine
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    • v.32 no.4
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    • pp.365-373
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    • 1998
  • Purpose: The conventional gamma camera is not ideal for scintimammography because of its large detector size (${\sim}500mm$ in width) causing high cost and low image quality. We are developing a small gamma camera dedicated for breast imaging. Materials and Methods: The small gamma camera system consists of a NaI (T1) crystal ($60 mm{\times}60 mm{\times}6 mm$) coupled with a Hamamatsu R3941 Position Sensitive Photomultiplier Tube (PSPMT), a resister chain circuit, preamplifiers, nuclear instrument modules, an analog to digital converter and a personal computer for control and display. The PSPMT was read out using a standard resistive charge division which multiplexes the 34 cross wire anode channels into 4 signals ($X^+,\;X^-,\;Y^+,\;Y^-$). Those signals were individually amplified by four preamplifiers and then, shaped and amplified by amplifiers. The signals were discriminated ana digitized via triggering signal and used to localize the position of an event by applying the Anger logic. Results: The intrinsic sensitivity of the system was approximately 8,000 counts/sec/${\mu}Ci$. High quality flood and hole mask images were obtained. Breast phantom containing $2{\sim}7 mm$ diameter spheres was successfully imaged with a parallel hole collimator The image displayed accurate size and activity distribution over the imaging field of view Conclusion: We have succesfully developed a small gamma camera using NaI(T1)-PSPMT and nuclear Instrument modules. The small gamma camera developed in this study might improve the diagnostic accuracy of scintimammography by optimally imaging the breast.

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Actual Condition of Quality Control of X-ray Imaging System in Primary Care Institution: focused on Gwangju Metropolitan City (1차 의료기관의 엑스선 발생장치 정도관리에 관한 현황조사:광주광역시 지역을 중심으로)

  • Dong, Kyung-Rae;Lee, Seun-Joo;Kweon, Dae-Cheol;Goo, Eun-Hoe;Jung, Jae-Eun;Lee, Kyu-Su
    • Journal of Radiation Protection and Research
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    • v.35 no.1
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    • pp.34-42
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    • 2010
  • With the expanded use of radiation in modern medical practices, the most important issue in regards to efforts to reduce individual exposure dose is quality assurance. Therefore in order to study the present condition of quality assurance, the Gwangju Metropolitan City area was divided into five districts each containing ten hospitals. Four experiments were conducted: a reproducibility experiment for kVp, mA, and examination time (sec) intensity of illumination; half-value layer (HVL) measurement; and beam perpendicularity test matching experiment. The tube voltage reproducibility experiment for all fifty hospitals resulted in a 95.33% passing rate and mA and examination time both resulted in a 77.0% passing rate. The passing rate for intensity of illumination was 86.0% and 52.0% for HVL, which was the lowest passing rate of all four factors. For the beam perpendicularity test matching experiment, generally the central flux is matched to within $1.5^{\circ}$. Of all fifty hospitals 30.0% were beyond $3^{\circ}$. The results of the survey showed that 58% responded that they knew about quality assurance cycle. All fifty respondents stated that they have not received any training in regards to quality assurance at their current place of employment. Although quality assurance is making relative progress, the most urgent issue is awareness of the importance of quality assurance. Therefore, the implementation of professional training focusing on safety management and accurate quality assurance of radiation will reduce the exposure to radiation for radiologists and patients and higher quality imaging using less dosage will also be possible.

Anatomy of Spleen Meridian Muscle in human (족태음비경근(足太陰脾經筋)의 해부학적(解剖學的) 고찰(考察))

  • Park Kyoung-Sik
    • Korean Journal of Acupuncture
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    • v.20 no.4
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    • pp.65-75
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    • 2003
  • This study was carried to identify the component of Spleen Meridian Muscle in human, dividing into outer, middle, and inner part. Lower extremity and trunk were opened widely to demonstrate muscles, nerve, blood vessels and the others, displaying the inner structure of Spleen Meridian Muscle. We obtained the results as follows; 1. Spleen Meridian Muscle is composed of the muscle, nerve and blood vessels. 2. In human anatomy, it is present the difference between a term of nerve or blood vessels which control the muscle of Meridian Muscle and those which pass near by Meridian Muscle. 3. The inner composition of meridian muscle in human arm is as follows ; 1) Muscle; ext. hallucis longus tend., flex. hallucis longus tend.(Sp-1), abd. hallucis tend., flex. hallucis brevis tend., flex. hallucis longus tend.(Sp-2, 3), ant. tibial m. tend., abd. hallucis, flex. hallucis longus tend.(Sp-4), flex. retinaculum, ant. tibiotalar lig.(Sp-5), flex. digitorum longus m., tibialis post. m.(Sp-6), soleus m., flex. digitorum longus m., tibialis post. m.(Sp-7, 8), gastrocnemius m., soleus m.(Sp-9), vastus medialis m.(Sp-10), sartorius m., vastus medialis m., add. longus m.(Sp-11), inguinal lig., iliopsoas m.(Sp-12), ext. abdominal oblique m. aponeurosis, int. abd. ob. m., transversus abd. m.(Sp-13, 14, 15, 16), ant. serratus m., intercostalis m.(Sp-17), pectoralis major m., pectoralis minor m., intercostalis m.(Sp-18, 19, 20), ant. serratus m., intercostalis m.(Sp-21) 2) Nerve; deep peroneal n. br.(Sp-1), med. plantar br. of post. tibial n.(Sp-2, 3, 4), saphenous n., deep peroneal n. br.(Sp-5), sural cutan. n., tibial. n.(Sp-6, 7, 8), tibial. n.(Sp-9), saphenous br. of femoral n.(Sp-10, 11), femoral n.(Sp-12), subcostal n. cut. br., iliohypogastric n., genitofemoral. n.(Sp-13), 11th. intercostal n. and its cut. br.(Sp-14), 10th. intercostal n. and its cut. br.(Sp-15), long thoracic n. br., 8th. intercostal n. and its cut. br.(Sp-16), long thoracic n. br., 5th. intercostal n. and its cut. br.(Sp-17), long thoracic n. br., 4th. intercostal n. and its cut. br.(Sp-18), long thoracic n. br., 3th. intercostal n. and its cut. br.(Sp-19), long thoracic n. br., 2th. intercostal n. and its cut. br.(Sp-20), long thoracic n. br., 6th. intercostal n. and its cut. br.(Sp-21) 3) Blood vessels; digital a. br. of dorsalis pedis a., post. tibial a. br.(Sp-1), med. plantar br. of post. tibial a.(Sp-2, 3, 4), saphenous vein, Ant. Med. malleolar a.(Sp-5), small saphenous v. br., post. tibial a.(Sp-6, 7), small saphenous v. br., post. tibial a., peroneal a.(Sp-8), post. tibial a.(Sp-9), long saphenose v. br., saphenous br. of femoral a.(Sp-10), deep femoral a. br.(Sp-11), femoral a.(Sp-12), supf. thoracoepigastric v., musculophrenic a.(Sp-16), thoracoepigastric v., lat. thoracic a. and v., 5th epigastric v., deep circumflex iliac a.(Sp-13, 14), supf. epigastric v., subcostal a., lumbar a.(Sp-15), intercostal a. v.(Sp-17), lat. thoracic a. and v., 4th intercostal a. v.(Sp-18), lat. thoracic a. and v., 3th intercostal a. v., axillary v. br.(Sp-19), lat. thoracic a. and v., 2th intercostal a. v., axillary v. br.(Sp-20), thoracoepigastric v., subscapular a. br., 6th intercostal a. v.(Sp-21)

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Designing Mobile Framework for Intelligent Personalized Marketing Service in Interactive Exhibition Space (인터랙티브 전시 환경에서 개인화 마케팅 서비스를 위한 모바일 프레임워크 설계)

  • Bae, Jong-Hwan;Sho, Su-Hwan;Choi, Lee-Kwon
    • Journal of Intelligence and Information Systems
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    • v.18 no.1
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    • pp.59-69
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    • 2012
  • As exhibition industry, which is a part of 17 new growth engines of the government, is related to other industries such as tourism, transportation and financial industries. So it has a significant ripple effect on other industries. Exhibition is a knowledge-intensive, eco-friendly and high value-added Industry. Over 13,000 exhibitions are held every year around the world which contributes to getting foreign currency. Exhibition industry is closely related with culture and tourism and could be utilized as local and national development strategies and improve national brand image as well. Many countries try various efforts to invigorate exhibition industry by arranging related laws and support system. In Korea, more than 200 exhibitions are being held every year, but only 2~3 exhibitions are hosted with over 400 exhibitors and except these exhibitions most exhibitions have few foreign exhibitors. The main reason of weakness of domestic trade show is that there are no agencies managing exhibitionrelated statistics and there is no specific and reliable evaluation. This might cause impossibility of providing buyer or seller with reliable data, poor growth of exhibitions in terms of quality and thus service quality of trade shows cannot be improved. Hosting a lot of visitors (Public/Buyer/Exhibitor) is very crucial to the development of domestic exhibition industry. In order to attract many visitors, service quality of exhibition and visitor's satisfaction should be enhanced. For this purpose, a variety of real-time customized services through digital media and the services for creating new customers and retaining existing customers should be provided. In addition, by providing visitors with personalized information services they could manage their time and space efficiently avoiding the complexity of exhibition space. Exhibition industry can have competitiveness and industrial foundation through building up exhibition-related statistics, creating new information and enhancing research ability. Therefore, this paper deals with customized service with visitor's smart-phone at the exhibition space and designing mobile framework which enables exhibition devices to interact with other devices. Mobile server framework is composed of three different systems; multi-server interaction, server, client, display device. By making knowledge pool of exhibition environment, the accumulated data for each visitor can be provided as personalized service. In addition, based on the reaction of visitors each of all information is utilized as customized information and so the cyclic chain structure is designed. Multiple interaction server is designed to have functions of event handling, interaction process between exhibition device and visitor's smart-phone and data management. Client is an application processed by visitor's smart-phone and could be driven on a variety of platforms. Client functions as interface representing customized service for individual visitors and event input and output for simultaneous participation. Exhibition device consists of display system to show visitors contents and information, interaction input-output system to receive event from visitors and input toward action and finally the control system to connect above two systems. The proposed mobile framework in this paper provides individual visitors with customized and active services using their information profile and advanced Knowledge. In addition, user participation service is suggested as well by using interaction connection system between server, client, and exhibition devices. Suggested mobile framework is a technology which could be applied to culture industry such as performance, show and exhibition. Thus, this builds up the foundation to improve visitor's participation in exhibition and bring about development of exhibition industry by raising visitor's interest.

Characteristics of Si Floating Gate Nonvolatile Memory Based on Schottky Barrier Tunneling Transistor (쇼트키 장벽 관통 트랜지스터 구조를 적용한 실리콘 나노점 부유 게이트 비휘발성 메모리 특성)

  • Son, Dae-Ho;Kim, Eun-Kyeom;Kim, Jeong-Ho;Lee, Kyung-Su;Yim, Tae-Kyung;An, Seung-Man;Won, Sung-Hwan;Sok, Jung-Hyun;Hong, Wan-Shick;Kim, Tae-You;Jang, Moon-Gyu;Park, Kyoung-Wan
    • Journal of the Korean Vacuum Society
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    • v.18 no.4
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    • pp.302-309
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    • 2009
  • We fabricated a Si nano floating gate memory with Schottky barrier tunneling transistor structure. The device was consisted of Schottky barriers of Er-silicide at source/drain and Si nanoclusters in the gate stack formed by LPCVD-digital gas feeding method. Transistor operations due to the Schottky barrier tunneling were observed under small gate bias < 2V. The nonvolatile memory properties were investigated by measuring the threshold voltage shift along the gate bias voltage and time. We obtained the 10/50 mseconds for write/erase times and the memory window of $\sim5V$ under ${\pm}20\;V$ write/erase voltages. However, the memory window decreased to 0.4V after 104seconds, which was attributed to the Er-related defects in the tunneling oxide layer. Good write/erase endurance was maintained until $10^3$ write/erase times. However, the threshold voltages moved upward, and the memory window became small after more write/erase operations. Defects in the LPCVD control oxide were discussed for the endurance results. The experimental results point to the possibility of a Si nano floating gate memory with Schottky barrier tunneling transistor structure for Si nanoscale nonvolatile memory device.

A study for diagnosis and pattern identification of Hwa-Byung (화병의 진단 및 변증유형에 관한 연구)

  • Lee, Hui-Young;Park, Jong-Hoon;Whang, Wei-Wan;Kim, Jong-Woo
    • Journal of Oriental Neuropsychiatry
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    • v.16 no.1
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    • pp.1-17
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    • 2005
  • Objective : This empirical research is performed to recognize diagnostic concept, pattern identification, and clinical features of Hwa-byung. In other words, the aims of this research are to examine the differences of the diagnosis between Hwa-Byung and the other psychiatric disorders, and to find out pattern identification, and clinical characteristics of Hwa-Byung for prescriptions of this syndrome. Method : In the experiment, there were participated 30 patients who were met for our criterions according to HBDIS (Hwa-Byung Diagnostic interview Schedule). These patients were diagnosed as Axis1 according to criterions of DSM-IV with administering SCID-I. OMS-prime was utilized for finding out pattern identification of oriental medicine. Symptom Check List-90-Revision(SCL-90-R), Hemilton rating Scale for Depression(HRSD), Heart Rate Variability(HRV), and Digital Infrared Thermographic imaging(D.I.T.I.) were also utilized to discover clinical characteristics of Hwa-Byung Patients. Results : 1. Regarding Sex-ratio, male subjects were 3(10%), and female subjects are 27(90%). The age of subjects ranged from 22 year old to 75 $(51.87{\pm}11.04;\:Mean{\pm}SD)$ 2. In the results of diagnosis on the basis of DSM-IV, the 17(56.67%) patients were MOD (Major Depressive Disorder), the 5(16.67%) patients were USD (Undifferentiated Somatoform Disorder), the 4(13.33%) patients were Dysthymic Disorder, the 3(10%) patients were GAD (Generalized Anxiety Disorder), and the 1(3.33%) was Panic Disorder. Two of the patients who diagnosed as MOD were diagnosed as Panic Disorder too, and one of them was diagnosed as Pain Disorder too. 3. Regarding pattern identification, Hwa-Byung is positively correlated to deficiency of Heart(心). and then to stagnancy of Liver-Gall bladder. Hwa-Byung is correlated deficiency symptom-complex rather than excessiveness symptom-complex. That is also correlated positively to Pathological heat and fire. 4. In SCL90-R, the mean of PSDI was $(75.3{\pm}10.7;\:Mean{\pm}SD)$. The each mean of the other 11 factors was distributed between50-70. 5. The mean of HRSD was $(17.9{\pm}5.6;\:Mean{\pm}SD)$ in the entire subject's group. Then the group of MDD was $20.9{\pm}4.4$ and the group of USD was $12.0{\pm}4.8$ 6. In the results of HRV. the mean of TP is $972.4{\pm}1174(Mean{\pm}SD)$, this is lower than normal range 1000-200. The other factors were within normal range. Then, there were no significant differences between them (p<0.05). 7. The temperatures of each acupoint have significant differences between HNl(印堂) and PC6(內關), between CV17(顫中) and PC6(內關), between HN1(印堂) and CV8(神闕), between CV17(顫中) and CV8(神闕) in comparison with the average of body temperature in the use of D.I.T.I. (p<0.01) 8. In the analysis of correlation between SCL-90-R, HRSD, HRV. and D.I.T.I. there were no significant results. According to results that the correlation was analyzed with only the MDD group as subjects, there was negative correlation between RMSSD of HRV and HRSD, between LF of HRV and PDSIof SCL-90-R, and between LF/HF of HRV and ANX, PSY, and PDSI of SCL-90-R. Conclusion : In the observation of clinical features of 30 cases of Hwa-Byung patients by using diverse structured tests, there could make diverse diagnosis as depressive disorder, anxiety disorder, and Somatoform Disorder. Particularly. MDD was highly distributed. Considering oriental medicine's pattern identification of Hwa-Byung, this syndrome is related strongly to Heart, and there were demonstrated deficiency symptom-complex, and Pathological heat and fire. One of the limits of this study is lack of control subject's group, therefore, in the future study, it requires reexamination through a comparative research with these data to complete this study.

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Physical properties of novel composite using Portland cement for retro-filling material (치근단 역충전용 포틀랜드 시멘트 신복합재료의 물리적 성질 고찰)

  • Lee, Sang-Jin;Cho, Ok-In;Yum, Ji-Wan;Park, Jeong-Kil;Hur, Bock;Kim, Hyeon-Cheol
    • Restorative Dentistry and Endodontics
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    • v.35 no.6
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    • pp.445-452
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    • 2010
  • Objectives: The aim of this study was to compare apical sealing ability and physical properties of MTA, MTA - AH-plus mixture (AMTA) and experimental Portland cement - Epoxy resin mixture (EPPC) for a development of a novel retro-filling material. Materials and Methods: Forty-nine extracted roots were instrumented and filled with gutta-percha. Apical root was resected at 3 mm and the retro-filling cavity was prepared for 3 mm depth. Roots were randomly divided into 3 groups of 15 roots each. The retro-filling was done using MTA, AMTA, and EPPC as the groups divided. Four roots were used as control groups. After setting in humid condition for 24 hours, the roots were immersed in 1% methylene blue dye solution for 72 hours to test the apical leakage. After immersion, the roots were vertically sectioned and photos were taken to evaluate microleakage. Setting times were measured with Vicat apparatus and digital radiographs were taken to evaluate aluminum equivalent thickness using aluminum step wedge. The results of microleakage and setting time were compared between groups using one-way ANOVA and Scheffe's post-hoc comparison at the significance level of 95%. Results: AMTA and EPPC showed less microleakage than MTA group (p < 0.05). AMTA showed the highest radio-opacity than other groups and the novel EPPC showed 5 mm aluminum thickness radio-opacity. EPPC showed the shortest initial and final setting times than other groups while the MTA showed the longest (p < 0.05). Conclusions: Under the condition of this study, the novel composite using Portland cement-Epoxy resin mixture may useful for retro-filling with the properties of favorable leakage resistance, radio-opacity and short setting time.