• Title/Summary/Keyword: I&C equipment

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Neuroprotective Effects of Modified Yuldahanso-tang (MYH) in a Parkinson's Disease Mouse Model (MPTP로 유도된 Parkinson's disease 동물 모델에서 열다한소탕 가감방 (MYH)의 신경 세포 보호 효과)

  • Go, Ga-Yeon;Kim, Yoon-Ha;Ahn, Taek-Won
    • Journal of Sasang Constitutional Medicine
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    • v.27 no.2
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    • pp.270-287
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    • 2015
  • Objectives To evaluate the neuroprotective effects of modified Yuldahanso-tang (MYH) in a Parkinson's disease mouse model. Methods 1) Four groups (each of 8 rats per group) were used in this study. 2) The neuroprotective effect of MYH was examined in a Parkinson's disease mouse model. C57BL/6 mice treated with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP, 30 mg/kg/day), intraperitoneal (i.p.) for 5 days. 3) The brains of 2 mice per group were removed and frozen at $-20^{\circ}C$, and the striatum-substantia nigra part was seperated. The protein volume was measured by Bradford method following Bio-Rad protein analyzing kit. Using mouse/Rat Dopamine ELISA Assay Kit. 4) The brains of 2 mice per group were separated and removed. TH-immunohistochemical was examined in the MPTP-induced Parkinson's disease mice to evaluate the neuroprotective effects of MYH on ST and SNpc. 5) Two mice out of each group were anesthetized and skulls were opened from occipital to frontal direction to take out the brains. The brains added TTC solution for 20 minutes for staining. 6) The water tank used for morris water maze test was filled with $28^{\circ}C$ water, and a round platform of 10cm in diameter was installed for mice to step on. The study was carried out once a day within 30 seconds, keep exercising to step on the platform in the pool. 7) The brains of two mice out of each group were fixed in 10% formaldehyde solution and paraphillin substance was infiltrated. They were fragmented by microtome, and observed under an optical microscope after Hematoxylin & Eosin staining. 8) A round acrylic cylinder with its upper side open was filled with clean water and depressive mouse models were forced to swim for 15 minutes. After 24 hours the animals were put in the same equipment for 5 minutes and were forced to swim. 9) The convenient, simple, and accurate high-performance liquid chromatography (HPLC) method was established for simultaneous determination of Neurotransmitters in MPTP-MYH group. Results 1) MYH possess Dopamine cell protective effect on MPTP-induced injury in striatum and substantia nigra pars compacta. 2) MYH inhibits the loss of tyrosine hydroxylase-immunoreacitive (TH-IR) cells in the striatum and substantia nigra pars compacta on MPTP-induced injury in C57BL/6 mice. 3) MYH possesses improvement effect on MPTP-induced memory deterioration in C57BL/6 mice through the reduction of prolongated Sort of lost time by MPTP injection using the Morris water maze test. 4) MYH possesses hippocampal neuron protective effect on MPTP-induced injury in C57BL/6 mice. 5) MYH possesses improvement effect on MPTP-induced motor behaviour deficits and depression in C57BL/6 mice through the reduction of prolongated losing motion by MPTP injection using the Forced swimming test. 6) MYH increases serotonin product amount on MPTP-induced injury in C57BL/6 mice. Conclusions This experiment suggests that the neuroprotective effect of MYH is mediated by the increase in Dopamin, TH-ir cell, Hippocampus and Serotonin. Furthermore, MYH essential oil may serve as a potential preventive or therapeutic agent regarding Parkinson's disease.

Systems for Production of Calves from Hanwoo(Korean Cattle) IVM/IVF/IVC Blastocyst III. Vitrification and One-Step Dilution of Hanwoo Blastocyst (체외생산된 한우 배반포기배로부터 송아지 생스을 위한 체계 III. 한우 배반포기배의 초자화 동결과 1단계 융해)

  • Kim, E.Y.;Kim, D.I.;Park, N.H.;Weon, Y.S.;Nam, H.K.;Lee, K.S.;Park, S.Y.;Yoon, S.H.;Park, S.P.;Chung, K.S.;Lim, J.H.
    • Korean Journal of Animal Reproduction
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    • v.23 no.4
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    • pp.293-301
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    • 1999
  • This study was to examine whether Hanwoo IVM/IVF/IVC blastocyst can be successfully survived in vitro/in vivo after vitrification and one-step dilution. For vitrification, blastocysts were serially exposed in glycerol (G) and ethylene glycol(EG) mixtures[10% (v Iv) G for 5 min., 10% G plus 20% EG (v/v) for 5 min., and 25% G plus 25% EG (v/v) for 30 sec.] which is diluted in 10% FBS added D-PBS. And then they were loaded in the straw, placed in cold nitrogen vapor for 3 min. and plunged into L$N_2$(-196$^{\circ}C$). One-step dilution within the straw was done in $25^{\circ}C$ and 36$^{\circ}C$ water for about 5 min. and 3 min., respectively. Recovered embryos after one-step dilution were cultured in cumulus cell mono-layered drop for 48 h or were transferred into recipient cows. When the embryo survival in vitro was assessed to re-expanded and hatched rates at 24 hand 48 h after one-step dilution, the results of vitrified group (85.4, 43.8%) was high, although these results were significantly lower than normal development (100.0, 63.3%) of control group, respectively (P<0.001, P<0.05). When in vitro survival of vitrified groups according to developmental stage was compared, the results of fast developed embryos (expanded blastocyst and early hatching blastocyst stage) were significantly higher than those of delayed developed one (early blastocyst stage) after one-step dilution (early hatching: 88.0, 48.0%: expanded: 81.1, 45.3%; early: 66.7, 14.3%) (P<0.05). Also, in case of in vitro survival of vitrified groups according to embryo age (day 7, 8 and 9), when embryo age was younger, in vitro survival was significantly higher (day 7: 67.3, 34.5%; day 8: 76.9, 40.7%; day 9: 60.9, 23.9%)(P<0.05). Finally, when in vivo development potential of vitrified and one-step diluted Hanwoo blastocysts was examined, 4 of 8 recipient (50%) cows became confirmed pregnant. These results demonstrated that our vitrification and one-step dilution technique can be applied easily and effectively on field trial without the equipment and embryological skills required for conservative dilution and transfer.

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The Performance Analysis and Design of Selling Spectacle Lenses in Domestic Market (국내 시판 안경렌즈의 성능 분석 및 설계)

  • Kim, Se-Jin;Lim, Hyeon-Seon
    • Journal of Korean Ophthalmic Optics Society
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    • v.15 no.4
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    • pp.355-360
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    • 2010
  • Purpose: Analysis performance for spectacle lens which sales in domestic market and optimization design a spectacle lens which is corrected aberration. Methods: Measured center thickness, radius and aspherical surface coefficient for spherical and aspherical lenses which were ${\pm}$5.00D. Refractive index for every lens was 1.6 and they came from 4 different companies. I used 3 types of equipment to measure lenses. ID-F150 (Mitutoyo) : Center Thickness, FOCOVISION (SR-2, Automation Robotics) : Radius, PGI 1240S (Taylor Hobson) : Aspherical surface coefficient. Designed a lens which had 27 mm of distance from lens rear surface to center of eye, 4 mm of pupil diameter and small aberration on center vision $30^{\circ}C$. To shorten axial distance compared with the measured lens rise merits for cosmetic. Lens Design tool was CODE V (Optical Research Associates). Results: -5.00D aspherical lens had somewhat high astigmatism and distortion compared with the spherical lens. But it had a merit for cosmetic because of short axial height and decrease edge thickness. Improved a performance of distortion and ascertain merits for cosmetic due to short axial height and decrease edge thickness same as (-) lens in case of +5.00 aspherical lens. Though an optimization process front surface aspherical lens had a good performance for astigmatism and distortion and the merit for beauty compared with measured spherical lens. Conclusions: Design trend for domestic aspherical lens is decrease axial height and thickness to increase a merit for cosmetic not but increase performance of aberration. From design theory for optimization design front surface aspherical spectacle lens which has improved performance of aberration and merit for cosmetic at the same time compared with the measured lens. Expect an improved performance from design back aspherical lens compared with front aspherical lens.

Vessel and Navigation Modeling and Simulation based on DEVS Formalism : Design for Navigation Simulation Architecture with Modeling for Critical Systems and Agents of Vessel (DEVS 형식론 기반의 선박 항해 모델링 및 시뮬레이션 (I) : 항해 시뮬레이션 아키텍처 설계와 선박 핵심 장비 및 에이전트 모델링)

  • Woo, Sang-Min;Lee, Jang-Se;Hwang, Hun-Gyu
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.23 no.9
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    • pp.1038-1048
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    • 2019
  • Recently, various systems have been developed to support ship navigation safety. In order to verify the usefulness of such a system, it is most ideal to try it on a real vessel, but there are many difficulties. As an alternative, usability verification methods applied with modelling and simulation (M&S) techniques are required such as FMSS, which is closest to reality, is very expansive to construct, and there needs the specialized operator. For this reason, this paper proposes a method to verify the navigation safety support system by modeling and simulation techniques based on the Discrete Event System Specification (DEVS) formalism. As a first step, we designed the navigation simulation architecture based on the SES/MB framework, and details on modelling ship core equipment and navigator agents based on the DEVS. Through this, we are able to implement the navigation simulation system for vessels, and evaluate the effectiveness of navigation safety support elements such as collision avoidance, etc. using developed scenarios.

Effect of Breed (Lean or Fat Pigs) and Sex on Performance and Feeding Behaviour of Group Housed Growing Pigs in a Tropical Climate

  • Renaudeau, D.;Giorgi, M.;Silou, F.;Weisbecker, J.L.
    • Asian-Australasian Journal of Animal Sciences
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    • v.19 no.4
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    • pp.593-600
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    • 2006
  • The effects of breed and sex on individual growth performance and feeding behaviour were studied between 45 and 90 kg BW in two replicates of forty group-housed pigs. The first and the second replicates were carried out during the warm season (i.e. between February and April 2003) and during the hot season (i.e. between August and October 2003), respectively. During the warm season, ambient temperature and relative humidity averaged $25.3^{\circ}C$ and 86.0%. The corresponding values for the hot season were $27.9^{\circ}C$ and 83.6%. The pigs were grouped in pens of 10 animals on the basis of breed (Creole or Large White) and sex (gilt or castrated male) and given ad libitum access to a grower diet (9.0 MJ/kg net energy and 158 g/kg crude protein) via feed intake recording equipment (Acema 48). An ear-tag transponder was inserted into each pig and this allowed the time, duration, and size of individual visits to be recorded. The growth performance and feeding pattern were significantly affected by breed, sex, and season. The Creole pigs (CR) had a lower average daily gain (ADG) (642 vs. 861 g/d, p<0.01) and carcass lean content ($LC_{90kg}$) (35.4 vs. 54.5%; p<0.01) and a higher backfat thickness at 90 kg BW ($BT_{90kg}$) (23.4 vs. 10.4 mm; p<0.01) than Large White pigs (LW) whereas the average daily feed intake (ADFI) was not affected by breed (2.34 vs. 2.22 kg/d, respectively for CR and LW pigs; p>0.10). Consequently, the food:gain ratio was higher in CR than in LW (3.65 vs. 2.58; p<0.01). CR had less frequent meals but ate more feed per meal than LW (5.9 vs. 8.8 meals/d and 431 vs. 279 g/meal; p<0.01). The rate of feed intake was lower (27.6 vs. 33.9 g/min; p<0.01) and the ingestion time per day and per meal were higher in CR than in LW (87.1 vs. 69.7 min/d and 15.8 vs. 8.4 min/meal; p<0.01). The ADFI and BT90 kg were higher (2.38 vs. 2.17 kg/d and 18.1 vs. 15.9 mm; p<0.05) and LC90 kg was lower (43.5 vs. 46.4%; p<0.01) in castrated males (CM) than in gilts (G) whereas ADG was not affected by sex (p = 0.12). The difference in lean content between CM and G was greater in CR than in LW. The ADFI and ADG were reduced during the hot season (2.18 vs.2.38 kg/d and 726 vs. 777 g/d, respectively; p<0.05) whereas feed conversion and carcass lean content were not affected by season (p>0.05). Average feeding time per meal and meal size decreased during the hot season (10.9 vs. 13.2 min/meal and 316 vs. 396 g/meal; p<0.01) whereas the rate of feed intake was not affected by season (p = 0.83). On average, 0.69 of total feed intake was consumed during the diurnal period. However, this partition of feed intake was significantly affected by breed, sex, and season. In conclusion, the breed, sex and season significantly affect performance and feeding pattern in growing pigs raised in a tropical climate. Moreover, the results obtained in the present study suggest that differences observed in BW composition between CR and LW are associated with difference in feeding behaviour, in particular, the short-term regulation of feed intake.

A Study in an Effective Programs for Emergency Care Delivery System (응급의료 전달체계의 충실 방안)

  • Kwon Sook Hee
    • Journal of Korean Public Health Nursing
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    • v.9 no.1
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    • pp.83-102
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    • 1995
  • As the society is being industrialized, the fast-paced economic development that has caused substantial increase in cerebrovascular and coronary artery diseases and the industrial development and increased use of means of transportation have resulted in the rapid rise of incidents in external injuries as well. So the pubic has become acutely aware of the need for fast and effective emergency care delivery system. The goal of emergency care delivery system is to meet the emergency care needs of patients. The emergency care delivery system is seeking to efficiently satisfy the care needs of people. Therefore the purpose of this study is designed to develop an effective programs for emergency care delivery system in Korea. The following specific objectives were investigated. This emergency care delivery system must have the necessary man power, for transfering the patients, communication net work, and emergency care facilities. 1) Man power Emergency care requires n0t only specialized traning in the emergency treatment but also knowledge and experience i11 other related area, so emergency care personnel traning program should be designed in order to adapt to the specific need of emergency patients. It will be necessary to ensure professional personnel who aquires the sufficient traning and experience for emergency care and to look for legal basis. We have to develop re-educational programs for emergency nurse specialist. They should be received speciality of emergency nursing care so that they will work actively and positively in emergency part. Emergency medical doctor and nurse specialist should be given an education which is related in emergency and critical care. Emergency care personnel will continue to provide both acute and continuing care as partner with other medical team. 2) Transfering the patients. Successful management of pre-hospital care requires adequate traning for the emergency medical technician. Traning program should be required to participate in a actual first aids activites in order to have apportunities to acquire practical skills as well as theoretical knowledge. The system of emergency medical technician should be remarkablly successful with first responder firefighters. Establishing this system must add necessary ambulances operating at any given time. It will be necessary to standardize the ambulance size and equipment. Ambulance should be arranged with each and every fire station. 3) Communication net work. The head office of emergency commumication network should be arranged with the head office of fire station in community. It is proposed that Hot-line system for emergency care should be introduce. High controlled ambulance and thirtial emergency center should simultaneously equip critical-line in order to communication with each other. Ordinary ambulance and secondary emergency facility should also simultaneously equip emergency-line in order to communication with each other. 4) Emergency care facilities. Primary emergency care facilities should be covered with the ambulatory emergency patients-minor illness and injuires. Secondary emergency care facilities should be covered with the emergency admission patients. Third emergency care center should be covered with the critical patients who need special treatments and operation. Secondary and third emergency care facilities should employ emergency medical doctor and emergency nurse specialist to treat in-patients with severe and acute illness and multiple injuires. It should be fashioned for a system of emergency facilities that meets emergency patients needs. Provide incentives for increased number of emergency care facilities with traning in personal/clinical emergency care. 5) Finance It is recommended to put the finance of a emergency care on a firm basis. The emergency care delivery system should be managed by the government or accreditted organizations. In order to facilitate this relevant program the fund is needed for more efficient and effective emergency researchs, service, programs, and policy. 6) Gaining understanding and co-operation of pubic It is also important to undertake pubic education to improve understanding of first aids and C. P. R of individuals, communities and business. It is proposed that teachers and health officers be certified in C. P. R. The C. P. R education can be powerful influence save lives. Lastly appropriate emergency care information must be provided to the pubic for assisting them in choosing emergency care.

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Pressure Drop Predictions Using Multiple Regression Model in Pulse Jet Type Bag Filter Without Venturi (다중회귀모형을 이용한 벤츄리가 없는 충격기류식 여과집진장치 압력손실 예측)

  • Suh, Jeong-Min;Park, Jeong-Ho;Cho, Jae-Hwan;Jin, Kyung-Ho;Jung, Moon-Sub;Yi, Pyong-In;Hong, Sung-Chul;Sivakumar, S.;Choi, Kum-Chan
    • Journal of Environmental Science International
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    • v.23 no.12
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    • pp.2045-2056
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    • 2014
  • In this study, pressure drop was measured in the pulse jet bag filter without venturi on which 16 numbers of filter bags (Ø$140{\times}850{\ell}$) are installed according to operation condition(filtration velocity, inlet dust concentration, pulse pressure, and pulse interval) using coke dust from steel mill. The obtained 180 pressure drop test data were used to predict pressure drop with multiple regression model so that pressure drop data can be used for effective operation condition and as basic data for economical design. The prediction results showed that when filtration velocity was increased by 1%, pressure drop was increased by 2.2% which indicated that filtration velocity among operation condition was attributed on the pressure drop the most. Pressure was dropped by 1.53% when pulse pressure was increased by 1% which also confirmed that pulse pressure was the major factor affecting on the pressure drop next to filtration velocity. Meanwhile, pressure drops were found increased by 0.3% and 0.37%, respectively when inlet dust concentration and pulse interval were increased by 1% implying that the effects of inlet dust concentration and pulse interval were less as compared with those changes of filtration velocity and pulse pressure. Therefore, the larger effect on the pressure drop the pulse jet bag filter was found in the order of filtration velocity($V_f$), pulse pressure($P_p$), inlet dust concentration($C_i$), pulse interval($P_i$). Also, the prediction result of filtration velocity, inlet dust concentration, pulse pressure, and pulse interval which showed the largest effect on the pressure drop indicated that stable operation can be executed with filtration velocity less than 1.5 m/min and inlet dust concentration less than $4g/m^3$. However, it was regarded that pulse pressure and pulse interval need to be adjusted when inlet dust concentration is higher than $4g/m^3$. When filtration velocity and pulse pressure were examined, operation was possible regardless of changes in pulse pressure if filtration velocity was at 1.5 m/min. If filtration velocity was increased to 2 m/min. operation would be possible only when pulse pressure was set at higher than $5.8kgf/cm^2$. Also, the prediction result of pressure drop with filtration velocity and pulse interval showed that operation with pulse interval less than 50 sec. should be carried out under filtration velocity at 1.5 m/min. While, pulse interval should be set at lower than 11 sec. if filtration velocity was set at 2 m/min. Under the conditions of filtration velocity lower than 1 m/min and high pulse pressure higher than $7kgf/cm^2$, though pressure drop would be less, in this case, economic feasibility would be low due to increased in installation and operation cost since scale of dust collection equipment becomes larger and life of filtration bag becomes shortened due to high pulse pressure.

Development of a Pre-treating Equipment and the Carcass Disposal System for Infected Poultry (감염가금 전처리 및 폐사가축 처리시스템 개발)

  • Hong, J.T.;Kim, H.J.;Yu, B.K.;Lee, S.H.;Hyun, C.S.;Ryu, I.S.;Oh, K.Y.;Kim, S.;Kwon, J.H.;Tack, D.S.
    • Journal of Animal Environmental Science
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    • v.17 no.2
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    • pp.81-92
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    • 2011
  • When we bury the infected poultry into the ground, we have many problems such as the difficulty of making sufficient area for burying, environmental contamination by the leachate, unpleasant ordor. Also, in case of burning the carcass of the infected poultry, there are some problems such as high cost, dust, unpleasant odor, etc. It could cause environmental contamination which many peoples and environmental organization complains about. In this study, we develop a treating system which treats the infected poultry carcass in a environmental method preventing the environment contamination. This system is composed of many processes. The euthanasia system uses rigid vinyl to trap and to do a euthanasia the infected poultry with lethal gas, carbon dioxide. And then, with the tractor attached grappler infected poultry carcass could be put into the carcass treating system. The euthanasia system uses rigid vinyl to trap the infected birds and to confine lethal gas, carbon dioxide. Infected poultry carcass are moved to carcass disposal system by collecting device which is attached at tractor. The carcass treatment system (capacity of disposal : 6.3 $m^3$) is installed on a truck and do one pass work, which is input, crush, stir, sterilize, and discharge treated carcass. 1,000 chickens was killed within 9.7min by $CO_2$ (300L/min) in the tent (10 $m^3$). The collecting device could carry 142 chickens at a time, and the movable carcass treatment system could sterilize 2 tons carcass per hour (at one time). This treatment systems was eco-friendly because it reduced the volume of carcass by 31.9% with no wastewater generation.

A Comparative Study of Production of [68Ga]PSMA-11 with or without Cassette Type Modules (비 카세트 방식과 카세트 방식을 이용한 [68Ga]PSMA-11의 자동 합성 방법 비교)

  • Hyun-Sik, Park;Byeong-Min, Jo;Hyun-Ho, An;Hong-Jin, Lee;Jin-Hyeong, Lee;Gyeong-Jae, Lee;Byung-Chul, Lee;Won-Woo, Lee
    • The Korean Journal of Nuclear Medicine Technology
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    • v.26 no.2
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    • pp.15-19
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    • 2022
  • Purpose [68Ga]PSMA-11 is needed the high reproducibility, excellent radiochemical yield and purity. In term of radiation safety, the radiation exposure of operator for its production also should be considered. In this work, we performed a comparative study for the fully automated synthesis of [68Ga]PSMA-11 between non-cassette type and cassette type. Materials and Methods Two different type of modules (TRACERlab FX N pro for non-cassette type and BIKBox for cassette type) were used for the automated production of [68Ga]PSMA-11. According to the previously identified elution profile, Only 2.5 ml with high radioactivity was used for the reaction. After adjusting the pH of the reaction solution with HEPES buffer solution, the precursor was added and reacted with at 95 ℃ for 15 minutes. The reaction mixture was separated and purified using a C18 light cartridge. The product was eluted with 50% EtOH/saline solution and diluted with saline. It was completed by sterilizing filter. In the non-cassette type, the aforementioned process must be prepared directly. However, in the cassette method, synthesis was possible simply by installing a kit that was already completed. Results Both total [68Ga]PSMA-11 production time were 25±3(non-cassette type) and 23±3 minutes(cassette type). The radiochemical yield of the non-cassette type(65.5±5.7%) was higher than that of the cassette type(61.6±4.8%) after sterilization filter. The non-cassette type took about 120 minutes of preparation time before synthesis due to washing of synthesizer and reagent preparation. However, since the cassette type does not require washing and reagent preparation, it took about 20 minutes to prepare before synthesis. Both type of synthesizer had a radiochemical high purity(>99%). Conclusion The non-cassette type production of [68Ga]PSMA-11 showed higher radiochemical yield and lower cost than the cassette type. However, The cassette type has an advantage in terms of preparation time, convenience, and equipment maintenance.

Mechanical and Operational Factors Affecting the Efficiency of Rice Polishing Machines (정미기의 능률에 미치는 기계적 요인및 작동조건에 관한 연구)

  • No, Sang-Ha
    • Journal of Biosystems Engineering
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    • v.1 no.1
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    • pp.15-15
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    • 1976
  • In analyzing the operational characteristics of a rice whitening machine, the internal radial pressure of the machine was measured using strain gage equipment. Changes in cylinder and feed screw configurations, screen type, cylinder speed and counter-pressure levels were examined to determine their impact on the quality and quantity of milled rice and the performance of the machine. The results are summarized as follows: 1. The internal radial pressure in the whitening chamber varied with the surface condition of the grain being processed. During the first or second pass through the machine, pressure was relatively low, reached a maximum after two to three passes with combinations I and II, three to six with combination III and then began to fall. 2. The pitch of the feed screw and the size of the feed gate opening which determine the rate of entry of grain into the whitening chamber, appeared to be the most important factor aff-::cting the degree of radial pressure, quality and quantity of milled rice and the efficiency of the machine. Using a feed screw with a wide pitch (4.8cm), radial pressure was relatively high and head rice recovery ratio \vere quite low. In this case capacity and machine effic?iency were much higher than obtained when using a feed screw with a narrow pitch (2.3cm). Very significant responses in radial pressure, head rice recovery rates and machine capacity were observed with changes in cylinder speed and counter-pressure levels when using the wide pitch feed screw. 3. The characteristics of the screen which surrounds the whitening chamber had an important effect on whitening efficiency. The existence of small protuberances on the original screen resulted in significant increases in both machine capacity and efficiency but without a significant decrease in head rice recovery or development of excessive radial pressure. Further work is required to determine the effects of screen surface conditions and the shape of the cylinderical steel roller on the rate of bran removal, machine efficiency and recovery rates. The size of the slotted perforations 0:1 the screen affects total milled rice recovery. The opening size on the original screen was fabricated to accommodate the round shape of Japonica rice varieties but was not suitable for the more slender Indica type. Milling Indica varieties with this screen resulted in a reduction in total milled rice recovery. 4. An increase in cylinder speed from 380 to 820 rpm produced a positive effect on head rice recovery for all machine combinations at every level of counter-pressure used in the tests. Head rice recovery was considerably lower at 380rpm using a wide screw pitch when compared to the results obtained at speeds from 600 to 820 r.p.m. The effects of cylinder speed On radial pressure, capacity and machine efficiency showed contrasting results, depending on the width of the feed screw pitch. With a narrow feed screw pitch (2.3cm), a direct proportional relationship was observed bet?ween cylinder speed and both radial pressure and machine efficiency. In contrast, using a 4.8 centimeter pitch feed roller produced a series of inverse relationships between the above variables. Based on the results of this study it is recommended when milling Indica type long grain rice varieties that the cylinder speed of the original machine be increased from 500-600 rmp up to a minimum of 800 rpm to obtain a greater abrasive effect between the grain and the screen. The pitch of the feed screw should be also reduced to decr?ease the level of internal radial pressure and to obtain higher machine efficiency and increased quality of milled rice with increased cylinder speeds. Further study on the interaction between cylinder speed and feed screw pitch is recommended. 5. An increase in the counter pressure level produced a negative effect On the head rice recovery with an increase in radial pressure, capacity, and machine efficiency over all combinations and at every level of cylinder speed. 6. Head rice recovery rates were conditioned primarily by the pressure inside the whitening chamber. According to the empirical cha racteristics curve developed in this study, the relationships of head rice recovery ($Y_h$) and machine capacity ($Y_c$/TEX>) to internal radial pressure ($X_p$) followed an inverse quadratic function and a linear function respectively: $$Y_h^\Delta=\frac{1}{{1.4383-0.2951X_p^\ast+0.1425X_p^{\ast\ast}}^2} , (R^2=0.98)$$$$Y_c^\Delta=-305.83+374.37X_p^{\ast\ast}, (R^2=0.88)$$The correlation between capacity and power consumption per unit of brown rice expressed in the following exponential function: $$Y_c^\Delta=1.63Y_c^{-0.7786^\{\ast\ast}, (R^2=0.94)$$These relationships indicate that when radial pressure increases above a certain range (1. 6 to 2.0 kg/$cm^2$ based On the results of the experiment) head ricerecovery decrea?ses in a quadratic relation with a inear increase in capacity but without any decrease in power consump tion per unit of brown rice. On the other hand, if radial pressure is below the range shown above, power consumption increases dramatically with a lin?ear decrease in capacity but without significant increases in head rice recovery. During the operation of a given whitening machine, the optimum radial pressure range or the correct capacity range should be selected by controlling the feed rate and/or counter-pressure keeping in mind the condition of the grain, particulary the hardness. It was observed that the total number of passes is related to radial pessure level, feed rate and counter-pressure level. The higher theradial pressure the fewer num?ber of pass required but with decreased head rice recovery. In particular, when using high feed rates, the total number of passes should be increased to more than three by reducing the counter-pressure level to avoid decreaseases in head rice recovery (less than 65 percent head rice recovery on the basis of brown rice) at every cylinder speed. 7. A rapid rise in grain temperature seemed to have a close relationship with the pressure generated inside the whitening chamber and, subsequently with head rice reco?very rates. The higher the rate of increase, the lower were the resulting head rice recoveries.