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INDIVIDUALIZED RECONSTRUCTION OF THE LOWER OCCLUSAL PLANE ACCORDING TO SKELETAL PATTERN (안면 골격 형태에 따른 하악 교합평면의 재구성)

  • Hyun, Seong-Wook
    • The korean journal of orthodontics
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    • v.25 no.4
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    • pp.465-485
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    • 1995
  • The purpose of this study is to locate the proper position of the lower occlusal plane according to individual skeletal pattern. Cephalometric films of 234 subjects of the control group, 358 of the pretreatment group and 358 of the treated group were analyzed to study proper relationships between vertical dimension ratio(VDR) and lower occlusomandibular plane angle(LOM). The control group was divided into two subgroups by the age. The first subgroup consisted of 113 subjects of the age 14 years and under and with the mean age of 10.82 years. The other subgroup consisted of 113 subjects of the age 18 years and above with the mean age of 23.76 years. The pretreatment group was divided into three subgroups by the age. The first subgroup consisted of 274 subjects of the age 14 years and under with the mean age of 11.36 years. The second subgroup consisted of 54 subjects of the age 14 through 18 years with the mean age of 15.4 years. The last subgroup consisted of 30 subjects of the age 18 years and above with the mean age of 21.35 years. The treated group was also divided into three subgroups by the age. The first subgroup consisted of 145 subjects of the age 14 years and under with the mean age of 12.91 years. The second subgroup consisted of 166 subjects of the age 14 through 18 years with the mean age of 15.64 years. The last subgroup consisted of 47 subjects of the age 18 years and above with the mean age of 21.61 years. Cephalometric films of the sample were traced. Measurements were made to a hundredth using a program specifically prepared for this study, and the results were entered into a 486DX PC. Means and Standard deviations of all the veriables were calculated for each group. Correlation coefficients between pertinent variables were calculated. Significance tests on those coefficients, one-way ANOVA and t-tests between variables or groups were performed. On the basis of the results studied above, certain subjects were selected from the control and the treated groups to locate the proper position of the occlusal plane, and designated as the optimal occluaion group. The subjects of this optimal occlusion group had 1-3 mm overbite, 1-3 mm of overjet and less than 1.75 mm of curve of Spee. A total subjects of 187 in this group consisted 104 treated subjects and 83 control group. Regression analysis was carried out between VDR and LOM, and regression equations were tabulated for this optimal occlusion group. The results were as follows : 1. Highly significant correlations were observed between various variables useful for identifying vertical component of skeletal frame, but any one particular variable did not accurately indicate the magnitude of anterior vertical overbite. 2. Of the variables useful identifying vertical component of skeletal frame, The VDR showed the highest correlation to the LOM. 3. Of the total sample, 80 percent had overbite within the normal range, irrespective of VDR. 4. The optimal occlusion group was divided into 9 subgroups by the age and the anteroposterior skeletal pattern, and correlation coefficient and determination coefficient between VDR and LOM of each group were calculated. Correlation coefficients and determination coefficients were found to be significantly high in all groups. 5. Regression equation was induced for each of the optimal occlusion group to find proper LOM according to the VDR. 6. It was found that the mean value of the cant of occlusal plane itself is not enough for a diagnosis and a treatment plan. Rather, It is very important to locate the proper occlusal plane for an Individual skeletal pattern.

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Studies on effect and Safety of various Aqua-acupunctures from Scutellariae Radix (다양(多樣)한 황금약침제제(黃芩藥鍼製劑)의 안전성(安定性) 및 효능(效能)에 관한 연구(硏究))

  • Kim, Ho-Kyoung;Ma, Jin-Yeul;Cheon, Won-Kyung;Yun, Su-Young;Kang, Eun-Jung;Joo, Hye-Jeong;Ko, Byoung-Seob
    • Korean Journal of Oriental Medicine
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    • v.3 no.1
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    • pp.183-197
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    • 1997
  • In order to detect the safety and effect of various aqua-acupunctures from Scutellariae Radix, the modifications of boiling, filtration and dilution were employed for the manufacture of aqua-acupunctures. We injected 0.2cc of aqua-acupunctures into Joksamri (足三里) of rat, repeatedly. We compared subacute toxicity of them with saline group, distilled water(D.W.) group, acupuncture group and control group. The results were summarized as follows: 1. The groups were all healthy and alive, and there was no special abnormality in physical condition and autopsy. And there were not any toxic symptoms in repeating application of aqua-acupunctures to the rat, including changes of body weight, organ weight, haematological examination and serum biochemical test. 2. There was slight change of body weight in acupuncture group : We could see significance after 3 days(p<0.05) and after 7 days(p<0.001) in body weight loss. After 9 days, all tested groups were suppressed in body weight increment. 3. Result of organ weight : In Palkang aqua-acupuncture(D-2 group), saline group and acupuncture group there were some statistical significance. Especially, acupuncture group revealed significant result in liver and spleen than aqua-acupunctures. From this result, we could suggest that the efficacy of acupuncture was preceded herbal medicine. 4. In serum biochemical test, we examined glucose(GLU), triglyceride(TG) and cholesterol(CHOL). In comparison with control group, the diluted 10 times of Hwanggum aqua-aqupuncture$({\times}10\;group)$ was recognized significant decrease of glucose, but the diluted 100 times of Hwanggum aqua-acupuncture$({\times}100\;group)$, D-2 group, saline group were confirmed significant increment. There was not any meaningful change of CHOL in all of tested group, excepting the acupuncture group was exhibited statistically significant decrease(p<0.05). In TG level all tested group except complex injection of standard compound(CPA group) and HG, there were significant value iii statistically. The diluted solution was more significant decrease than Hwanggum aqua-acupuncture(HG). The mutual relationship of components of aqua-acupunture tended to decrease level of TG, regardless of its concentration. In acupunture guoup, we gained some interesting result In meaningful decrease in 7G. 5. Haematological examination showed significant increment of granulocytes(GR) in all tested groups except Hwanggum aqua-acupuncture. And the diluted solutions of HG expressed very high increment of them(p<0.001). The GR and Mean Corpuscular Volume(MCV) of acupuncture group showed statistical significance.

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Performance and Carcass Ratio of Large-type Female Broiler at Different Stocking Densities (다양한 사육밀도에서 대형 육계 수컷의 생산성과 도체수율)

  • Na, Jae-Cheon;HwangBoa, Jong;Kim, Ji-Hyuk;Kang, Hwan-Gu;Kim, Min-Ji;Kim, Dong-Wook;Choi, Hee-Cheol;Hong, Eui-Chul
    • Korean Journal of Poultry Science
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    • v.39 no.4
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    • pp.305-310
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    • 2012
  • This work was carried out to investigate performance and carcass yield of large-type broilers at different stocking densities. Treatments were T1 (9.1 birds/$m^2$), T2 (10.3 birds/$m^2$) and T3 (11.5 birds/$m^2$) by the stocking density. Four hundred eight 1-day-old Arbor Acre broiler chicks were used for six weeks (starter, 0~1 wks; earlier, 1~3 wks; finisher, 3~6 wks) and divided into 3 treatments (4 replications/treatment, 30, 34 or 38 birds/replication). Research indexes were rearing viability ratio, body weight, body weight gain, feed intake, feed conversion ratio, production efficiency factor and carcass ratio. Rearing viability ratio (%) was 89% or more for all treatments and there was no significant difference on weekly rearing viability ratio (%). Body weight of T2 was the greatest and that of T3 was the lowest at 1 weeks old (P<0.05). Body weight gain of T2 was the greatest and that of T3 was the lowest at 0~1 weeks old (P<0.05). However, body weight gain of T3 was the greatest and that of T1 was the lowest at 1~2 weeks old (P<0.05). Body weight gain of T2 was the greatest as 3,031 g among treatments at 0~6 weeks old (P<0.05). Feed intakes of T1, T2 and T3 were 1,417 g, 1,265 g and 1,355 g, respectively, and that of T1 was the greatest among treatments (P<0.05). There was no significant difference on body weight, body weight gain and feed intake. Feed conversion ratio of T1 was the greatest among treatments at 1~2 wks, 3~4 wks and 0~6 wks old (P<0.05). Production efficiency factors of T1, T2 and T3 were 363.5, 388.3 and 358.3, respectively, and there was no significant difference among treatments. Wing meat ratio of T1 was the higher compared to other treatments at the age of 4 wk (P<0.05). There was no significant difference on carcass ratio and partial meat ratio among treatments. Neck meat ratio of T2 was the lowest among treatments (P<0.05). This result may provide the standard data of different stocking densities for large-type broiler and the further research is needed.

Effect of the Induced Molting with Low-Protein and Energy Diet on the Postmolt Performance and Egg Quality of Layers (저단백질, 저에너지 사료를 이용한 유도환우가 산란계의 생산성 및 난질에 미치는 영향)

  • Hong, Eui-Chul;Park, Hee-Du;Na, Seung-Hwan;Kim, Hak-Kyu;Yu, Dong-Jo;Park, Mi-Na;Jung, Kie-Chul;Choo, Hyo-Jun;Seo, Ok-Suk;Choi, Yang-Ho;HwangBo, Jong
    • Korean Journal of Poultry Science
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    • v.37 no.2
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    • pp.117-123
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    • 2010
  • This work was carried out to investigate the effect of the induced molting with low-protein and energy diet on the postmolt performance of layers. Eighty White Leghorn layers (61-old-wk) with over 80% egg production were used for 12 weeks in this work. Treatments were non-molt control (CO), fasting treatment for 10 days (FW), molt treatment with low-protein and low-energy molting diet for 3 weeks (LO), and molt treatment with standard molting diet for 3 weeks (ST) as 4 treatments (2 replications/treatment and 10 birds/replication). Body weight (BW) loss was 26.5% of initial BW at 2 week in FW treatment, and was 17.3% and 14.2% in both LO and ST treatments (P<0.05). Layers in molting treatments were fed with commercial layer diet after completion of molting since BW of layers was recovered for 7 weeks. Heart weight ratio was shown as 0.47, 0.43, 0.46 and 0.46% at CO, FW, LO and ST treatments, respectively, and liver weight ration of body weight was shown as 2.56, 1.30, 1.47 and 1.52%, respectively. Thus, those of molting treatments decreased compared to non-molt control (P<0.05). Oviduct weight ratio were shown as 3.95, 1.17, 1.54 and 1.67%, respectively, and similar with the results of liver (P<0.05). Feed intake decreased at LO and ST treatments during molting period and increased from the 5th week compared to control. Egg production decreased at 1 week in molt treatment and stopped at 2 week in FW, 3 week in LO, and 4 week in ST treatments. The birds started to lay egg at 4 week in FW and at 5 week in LO and ST treatments. Egg production was recovered until 50% at 6 week in FW and was recovered as 66.1 and 71.6% at 8 week in LO and ST treatment, respectively. Egg weights were similar among all treatments. Eggshell thicknesses were 0.41, 0.47, 0.46 and 0.46 mm at CO, FW, LO and ST treatment, respectively, but the higher in molt treatments than control (P<0.05). Eggshell breaking strength was 3.83 and 3.81 kg/$cm^2$ in FW and LO treatment, respectively, and high compared to control. However, eggshell breaking strengths were 3.54 and 3.78 kg/$cm^2$ and were not statistically different. Haugh units were 75.6, 81.1, 80.6 and 79.9 in 4 treatments and high in molt treatment. Finally, dietary low-protein and low-energy may induce molt as few effect on performance of layers.

Study of the Impact of Light Through the Vitamin $B_{12}$/Folate Inspection (Vitamin $B_{12}$/Folate 검사 시 빛의 영향에 대한 고찰)

  • Cho, Eun Bit;Pack, Song Ran;Kim, Whe Jung;Kim, Seong Ho;Yoo, Seon Hee
    • The Korean Journal of Nuclear Medicine Technology
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    • v.16 no.2
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    • pp.162-166
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    • 2012
  • Purpose : Vitamin $B_{12}$ and Folate are for anemia work-up which is well known for its sensitivity of light; the screening manual also specifies to be careful with light conditions. According to this, our laboratory minimized the exposure of light when inspecting the Vitamin $B_{12}$ and Folate, but the exposure cannot be wholly blocked due to other various factors such as when conducting specimen segregation. Thus, this inspection is to identify to what extent light can influence and whether the exclusion of light is mandatory during the Vitamin $B_{12}$/Folate test. Materials and Methods : We have conducted two experiments of identifying the extent of light's influence when conducting the Vitamin $B_{12}$/Folate test and also when specimens are under preservation. These experiments were progressed with various concentrations of patients' specimens which were requested to our hospital in March 2012. The first experiment is to verify the results on Vitamin $B_{12}$/Folate dependent on light exposure during the experiment. In the process, we have compared the results of light exposure/exclusion during the incubation process after the reagent division. The second experiment is about the impact of light exposure on the results on Vitamin $B_{12}$/Folate during the preservation. For 1, 2, 7 days the light on the specimen were wholly blocked and were preserved under $-15^{\circ}C$ temperature refrigeration. Then, we compared the results of light-excluded specimen and the exposed one. Results : When conducting first experiment, there were no noticeable changes in the Standard and specimen's cpm, but for Vitamin $B_{12}$, the average result of specimen exposed to light increased 7.8% compare to that of excluded one's. Furthermore, in the significant level 0.05, the significance probability or the p-value was 0.251 which means it has no impact. For Folate, the result being exposed to light decreased 5.4%, the significance probability was 0.033 which means it has little impact. For the second preservation, the result was dependent on the light exposure. The first day of preservation of Vitamin $B_{12}$, the clinical material exposed to light was 11.6%, second day clinical material exposed to light was 10.8%, seventh day clinical material exposed to light increased 3.8%, the significance probability of the $1^{st}$, $2^{nd}$, $7^{th}$ day is 0.372, 0.033, 0.144 respectively, and which indicates that the $1^{st}$ and $7^{th}$ day seems to have no impact. For Folate's case, the clinical material exposed to light has increased 1.4% but hardly had impact, $2^{nd}$ day clinical material being exposed to light was 6.1%, $7^{Th}$ day clinical material being exposed to light decreased 5.2%. The significance probability of Folate on the $1^{st}$, $2^{nd}$, $7^{th}$ day is 0.378, 0.037, 0.217 respectively, and the $1^{st}$ day and the $7^{th}$ day seems to have no impact. Conclusion : After scrutinizing the impact of light exposure/exclusion, Vitamin $B_{12}$ has no impact, while Folate seems to have no noticeable influence but light exclusion is recommended due to its significance probability of 0.033 when conducting experiment. During the preservation, the $2^{nd}$ day result depend on the light exclusion seems to have impact or influence. However, to consider the complication of the experimental process, the experiment including technical errors is predictable. Hence, it is likely to have no impact of light. Nevertheless, it is recommendable to exclude the light during the long preservation as per the significance probability (p-value) of $1^{st}$ and $7^{th}$ day has been diminished.

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A study on the gratification of the patient in the Dental Hospital (치과병원 내원환자의 만족도 조사분석)

  • Kim, Min-Young;Lee, Keun-Woo;Moon, Hong-Suk;Chung, Moon-Kyu
    • The Journal of Korean Academy of Prosthodontics
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    • v.46 no.1
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    • pp.65-82
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    • 2008
  • Statement of problem : Today's market economy has been changed more and more to consumer concerned. It is owing to not only consumers ' rising standard of living and education, but also purchasers' easy accessibilities to products through various mass media. The consumer centered market system, where customer can choose items with diverse alternatives to satisfy their self esteem, is also applied to the field of medical business, and accelerated by an increasing income level of shoppers and introducing the whole nations' medical insurance system. Today, the medical industry has become competitive due to increasing number of medical institutions and medical personnel, and this offers wide choices to consumers in the medical market place. At this point of time, it is essential to survey on the primary factor of gratification for the patient in the Dental clinic, as well as on the problems and suggestions in medical service. Purpose : The analysis in this study shows essential factors and expected influential elements in satisfaction of the patient in the Dental Hopsital, and strategic suggestions for the provider of dental service, which can be of benefit to the prospective customer as well as can make improvement in the quality of dental treatment service. Material and method : This study had been researched by collecting and analyzing the organized questionnaires, which were filled in directly from 784 patients, who visit Dental Hospital, Yonsei University in Seoul, from January 23rd to April 15th. Result : It can be summarized like the followings. 1. The social and demographical peculiarities of respondents are as follows. Samples of gender and marital status are adequately extracted, but data on occupation and treatment are are under a bias toward students, undergraduates and graduate students, and orthodontics. 2. 74% of patients who answer the questionnaire were highly satisfied with the service of dental clinic in the section of overall satisfaction. 3. The survey result about specific service of dental treatment, within sections of independent variables, is like the followings; Patients are highly gratified with service system, kindness, explanation, explanation on expected waiting hours, reservation system, emergency measures, expert treatment, existence of knowledge of dentistry, size of hospital, disinfection, equipment and parking, but lowly satisfied with expense of treatment, preparatory hours for treatment, waiting hours, treatment hours and the period of subscription. 4. The correlation analysis showed that there is no significant linear relationship between the independent variables. 5. The probit regression analysis showed that 8 out of 34 independent variables explained the dependent variables at the level of 0.01. 6. It shows that 8 independent variables, which can affect customers 'satisfaction, are clearing up of inconvenience, service system, kindness, explanation, treatment hours per attendance, reservation system, existence of knowledge of dentistry, and contentment of equipment in the hospital. Conclusion : The consumer's satisfaction totally relies on subjective evaluations of customers. Providing appropriate service, which can meet the criteria for the customer who demands various wares, pursues luxury goods, and expects high quality of medical service, is essential to fulfill patients' satisfaction. Many medical institutions do their best to satisfy their customer, touch their consumer, and offer patience centered services, and it is also applied to the field of dentistry. Establishing brand new strategic managements and elevating the quality of dental service based on this survey are required to improve the satisfaction of patience in the Dental Hospital.

Biomass and distribution of Antarctic Krill, Euphausia superba, in the Northern part of the South Shetland Islands, Antarctic Ocean (남극 남쉐틀란드 군도 북부 해역의 크릴 분포 및 자원량)

  • KANG Donhyug;HWANG Doojin;KIM Suam
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.32 no.6
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    • pp.737-747
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    • 1999
  • To estimate biomass and distribution of the Antarctic krill (Euphausia superba), hydroacoustic survey was conducted on board of R/V Yuzhmorgeologiya, which was chartered by Korea Antarctic Research Program (KARP) group from 18 to 21 December 1998, in the northern part of the South Shetland Islands, Antarctic Ocean, The scientific echo sounder (towing body type) used was EK- 500 (SIMRAD, Norway) with echo integrator (BI-500) at 38 kHz frequency and recorded mean backscattering cross-section coefficient (SA) per 1 $mile^2$ of sea surface. Also, Bongo net sampling was carried out to determine the size of krill and CTD (Conductivity, Temperature and Depth) casting to understand physical structure. Water column was divided into 5 layers (22$\~$65 m, 65$\~$115 m, l15$\~$65 m, 165$\~$215 m and 215$\~$315 m) to know vertical distribution of krill biomass. The standard length of krill collected was between 30 mm and 51 mm, and adult krill had single mode (41 mm). Maximum horizontal length of krill patch was about 35 nautical mile and vertical thickness was about 275 m. High density of krill was appeared in frontal area between Circumpolar Deep Water (>$1^{\circ}C$) and very low temperature water mass (< $-0.5^{\circ}C$) that originate from Weddell Sea. According to the results calculated using target strength equation, krill density was totally higher in continental slope and open water areas than in coastal area. In the study area, krill seems to distribute in depth; density was low at first layer ($\={\rho}=17.0\;g/m^2$) and higher at fourth layer ($\={\rho}=40.19\;g/m^2$). The estimated krill biomass at total survey area and water column was about 2.77 million metric ion ($\={\rho}=151.0\;g/m^2$) and coefficient of valiance ( CV, $\%$) was 19.92. The proportions and biomass of krill biomass at each layer were as follows; layer 1 ($11.3\%$, 0.31 million metric ton, CV=16.24), layer 2 ($13.3\%$, 0.37 million metric ton, CV=34.91), layer 3 ($23.7\%$, 0.66 million metric ton, CV=41.5), layer 4 ($26.6\%$, 0.74 million metric ton, CV=27.84) and layer 5 ($25\%$, 0.69 million metric ton, CV= 26.83).

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The Measurement of Sensitivity and Comparative Analysis of Simplified Quantitation Methods to Measure Dopamine Transporters Using [I-123]IPT Pharmacokinetic Computer Simulations ([I-123]IPT 약역학 컴퓨터시뮬레이션을 이용한 민감도 측정 및 간편화된 운반체 정량분석 방법들의 비교분석 연구)

  • Son, Hye-Kyung;Nha, Sang-Kyun;Lee, Hee-Kyung;Kim, Hee-Joung
    • The Korean Journal of Nuclear Medicine
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    • v.31 no.1
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    • pp.19-29
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    • 1997
  • Recently, [I-123]IPT SPECT has been used for early diagnosis of Parkinson's patients(PP) by imaging dopamine transporters. The dynamic time activity curves in basal ganglia(BG) and occipital cortex(OCC) without blood samples were obtained for 2 hours. These data were then used to measure dopamine transporters by operationally defined ratio methods of (BG-OCC)/OCC at 2 hrs, binding potential $R_v=k_3/k_4$ using graphic method or $R_A$= (ABBG-ABOCC)/ABOCC for 2 hrs, where ABBG represents accumulated binding activity in basal ganglia(${\int}^{120min}_0$ BG(t)dt) and ABOCC represents accumulated binding activity in occipital cortex(${\int}^{120min}_0$ OCC(t)dt). The purpose of this study was to examine the IPT pharmacokinetics and investigate the usefulness of simplified methods of (BG-OCC)/OCC, $R_A$, and $R_v$ which are often assumed that these values reflect the true values of $k_3/k_4$. The rate constants $K_1,\;k_2\;k_3$ and $k_4$ to be used for simulations were derived using [I-123]IPT SPECT and aterialized blood data with a standard three compartmental model. The sensitivities and time activity curves in BG and OCC were computed by changing $K_l$ and $k_3$(only BG) for every 5min over 2 hours. The values (BG-OCC)/OCC, $R_A$, and $R_v$ were then computed from the time activity curves and the linear regression analysis was used to measure the accuracies of these methods. The late constants $K_l,\;k_2\;k_3\;k_4$ at BG and OCC were $1.26{\pm}5.41%,\;0.044{\pm}19.58%,\;0.031{\pm}24.36%,\;0.008{\pm}22.78%$ and $1.36{\pm}4.76%,\;0.170{\pm}6.89%,\;0.007{\pm}23.89%,\;0.007{\pm}45.09%$, respectively. The Sensitivities for ((${\Delta}S/S$)/(${\Delta}k_3/k_3$)) and ((${\Delta}S/S$)/(${\Delta}K_l/K_l$)) at 30min and 120min were measured as (0.19, 0.50) and (0.61, 0,23), respectively. The correlation coefficients and slopes of ((BG-OCC)/OCC, $R_A$, and $R_v$) with $k_3/k_4$ were (0.98, 1.00, 0.99) and (1.76, 0.47, 1.25), respectively. These simulation results indicate that a late [I-123]IPT SPECT image may represent the distribution of the dopamine transporters. Good correlations were shown between (3G-OCC)/OCC, $R_A$ or $R_v$ and true $k_3/k_4$, although the slopes between them were not unity. Pharmacokinetic computer simulations may be a very useful technique in studying dopamine transporter systems.

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Performance Characteristics of 3D GSO PET/CT Scanner (Philips GEMINI PET/DT) (3차원 GSO PET/CT 스캐너(Philips GEMINI PET/CT의 특성 평가)

  • Kim, Jin-Su;Lee, Jae-Sung;Lee, Byeong-Il;Lee, Dong-Soo;Chung, June-Key;Lee, Myung-Chul
    • The Korean Journal of Nuclear Medicine
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    • v.38 no.4
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    • pp.318-324
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    • 2004
  • Purpose: Philips GEMINI is a newly introduced whole-body GSO PET/CT scanner. In this study, performance of the scanner including spatial resolution, sensitivity, scatter fraction, noise equivalent count ratio (NECR) was measured utilizing NEMA NU2-2001 standard protocol and compared with performance of LSO, BGO crystal scanner. Methods: GEMINI is composed of the Philips ALLEGRO PET and MX8000 D multi-slice CT scanners. The PET scanner has 28 detector segments which have an array of 29 by 22 GSO crystals ($4{\times}6{\times}20$ mm), covering axial FOV of 18 cm. PET data to measure spatial resolution, sensitivity, scatter fraction, and NECR were acquired in 3D mode according to the NEMA NU2 protocols (coincidence window: 8 ns, energy window: $409[\sim}664$ keV). For the measurement of spatial resolution, images were reconstructed with FBP using ramp filter and an iterative reconstruction algorithm, 3D RAMLA. Data for sensitivity measurement were acquired using NEMA sensitivity phantom filled with F-18 solution and surrounded by $1{\sim}5$ aluminum sleeves after we confirmed that dead time loss did not exceed 1%. To measure NECR and scatter fraction, 1110 MBq of F-18 solution was injected into a NEMA scatter phantom with a length of 70 cm and dynamic scan with 20-min frame duration was acquired for 7 half-lives. Oblique sinograms were collapsed into transaxial slices using single slice rebinning method, and true to background (scatter+random) ratio for each slice and frame was estimated. Scatter fraction was determined by averaging the true to background ratio of last 3 frames in which the dead time loss was below 1%. Results: Transverse and axial resolutions at 1cm radius were (1) 5.3 and 6.5 mm (FBP), (2) 5.1 and 5.9 mm (3D RAMLA). Transverse radial, transverse tangential, and axial resolution at 10 cm were (1) 5.7, 5.7, and 7.0 mm (FBP), (2) 5.4, 5.4, and 6.4 mm (3D RAMLA). Attenuation free values of sensitivity were 3,620 counts/sec/MBq at the center of transaxial FOV and 4,324 counts/sec/MBq at 10 cm offset from the center. Scatter fraction was 40.6%, and peak true count rate and NECR were 88.9 kcps @ 12.9 kBq/mL and 34.3 kcps @ 8.84 kBq/mL. These characteristics are better than that of ECAT EXACT PET scanner with BGO crystal. Conclusion: The results of this field test demonstrate high resolution, sensitivity and count rate performance of the 3D PET/CT scanner with GSO crystal. The data provided here will be useful for the comparative study with other 3D PET/CT scanners using BGO or LSO crystals.

Derivation of the Synthetic Unit Hydrograph Based on the Watershed Characteristics (유역특성에 의한 합성단위도의 유도에 관한 연구)

  • 서승덕
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.17 no.1
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    • pp.3642-3654
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    • 1975
  • The purpose of this thesis is to derive a unit hydrograph which may be applied to the ungaged watershed area from the relations between directly measurable unitgraph properties such as peak discharge(qp), time to peak discharge (Tp), and lag time (Lg) and watershed characteristics such as river length(L) from the given station to the upstream limits of the watershed area in km, river length from station to centroid of gravity of the watershed area in km (Lca), and main stream slope in meter per km (S). Other procedure based on routing a time-area diagram through catchment storage named Instantaneous Unit Hydrograph(IUH). Dimensionless unitgraph also analysed in brief. The basic data (1969 to 1973) used in these studies are 9 recording level gages and rating curves, 41 rain gages and pluviographs, and 40 observed unitgraphs through the 9 sub watersheds in Nak Oong River basin. The results summarized in these studies are as follows; 1. Time in hour from start of rise to peak rate (Tp) generally occured at the position of 0.3Tb (time base of hydrograph) with some indication of higher values for larger watershed. The base flow is comparelatively higher than the other small watershed area. 2. Te losses from rainfall were divided into initial loss and continuing loss. Initial loss may be defined as that portion of storm rainfall which is intercepted by vegetation, held in deppression storage or infiltrated at a high rate early in the storm and continuing loss is defined as the loss which continues at a constant rate throughout the duration of the storm after the initial loss has been satisfied. Tis continuing loss approximates the nearly constant rate of infiltration (${\Phi}$-index method). The loss rate from this analysis was estimated 50 Per cent to the rainfall excess approximately during the surface runoff occured. 3. Stream slope seems approximate, as is usual, to consider the mainstreamonly, not giving any specific consideration to tributary. It is desirable to develop a single measure of slope that is representative of the who1e stream. The mean slope of channel increment in 1 meter per 200 meters and 1 meter per 1400 meters were defined at Gazang and Jindong respectively. It is considered that the slopes are low slightly in the light of other river studies. Flood concentration rate might slightly be low in the Nak Dong river basin. 4. It found that the watershed lag (Lg, hrs) could be expressed by Lg=0.253 (L.Lca)0.4171 The product L.Lca is a measure of the size and shape of the watershed. For the logarithms, the correlation coefficient for Lg was 0.97 which defined that Lg is closely related with the watershed characteristics, L and Lca. 5. Expression for basin might be expected to take form containing theslope as {{{{ { L}_{g }=0.545 {( { L. { L}_{ca } } over { SQRT {s} } ) }^{0.346 } }}}} For the logarithms, the correlation coefficient for Lg was 0.97 which defined that Lg is closely related with the basin characteristics too. It should be needed to take care of analysis which relating to the mean slopes 6. Peak discharge per unit area of unitgraph for standard duration tr, ㎥/sec/$\textrm{km}^2$, was given by qp=10-0.52-0.0184Lg with a indication of lower values for watershed contrary to the higher lag time. For the logarithms, the correlation coefficient qp was 0.998 which defined high sign ificance. The peak discharge of the unitgraph for an area could therefore be expected to take the from Qp=qp. A(㎥/sec). 7. Using the unitgraph parameter Lg, the base length of the unitgraph, in days, was adopted as {{{{ {T}_{b } =0.73+2.073( { { L}_{g } } over {24 } )}}}} with high significant correlation coefficient, 0.92. The constant of the above equation are fixed by the procedure used to separate base flow from direct runoff. 8. The width W75 of the unitgraph at discharge equal to 75 per cent of the peak discharge, in hours and the width W50 at discharge equal to 50 Per cent of the peak discharge in hours, can be estimated from {{{{ { W}_{75 }= { 1.61} over { { q}_{b } ^{1.05 } } }}}} and {{{{ { W}_{50 }= { 2.5} over { { q}_{b } ^{1.05 } } }}}} respectively. This provides supplementary guide for sketching the unitgraph. 9. Above equations define the three factors necessary to construct the unitgraph for duration tr. For the duration tR, the lag is LgR=Lg+0.2(tR-tr) and this modified lag, LgRis used in qp and Tb It the tr happens to be equal to or close to tR, further assume qpR=qp. 10. Triangular hydrograph is a dimensionless unitgraph prepared from the 40 unitgraphs. The equation is shown as {{{{ { q}_{p } = { K.A.Q} over { { T}_{p } } }}}} or {{{{ { q}_{p } = { 0.21A.Q} over { { T}_{p } } }}}} The constant 0.21 is defined to Nak Dong River basin. 11. The base length of the time-area diagram for the IUH routing is {{{{C=0.9 {( { L. { L}_{ca } } over { SQRT { s} } ) }^{1/3 } }}}}. Correlation coefficient for C was 0.983 which defined a high significance. The base length of the T-AD was set to equal the time from the midpoint of rain fall excess to the point of contraflexure. The constant K, derived in this studies is K=8.32+0.0213 {{{{ { L} over { SQRT { s} } }}}} with correlation coefficient, 0.964. 12. In the light of the results analysed in these studies, average errors in the peak discharge of the Synthetic unitgraph, Triangular unitgraph, and IUH were estimated as 2.2, 7.7 and 6.4 per cent respectively to the peak of observed average unitgraph. Each ordinate of the Synthetic unitgraph was approached closely to the observed one.

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