• Title/Summary/Keyword: Three Rs

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Investigation of the cytotoxicity of thermoplastic denture base resins

  • Lee, Jung-Hwan;Jun, Soo-Kyung;Kim, Si-Chul;Okubo, Chikahiro;Lee, Hae-Hyoung
    • The Journal of Advanced Prosthodontics
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    • v.9 no.6
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    • pp.453-462
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    • 2017
  • PURPOSE. The purpose of this study was to investigate the in vitro cytotoxicity of thermoplastic denture base resins and to identify the possible adverse effects of these resins on oral keratinocytes in response to hot water/ food intake. MATERIALS AND METHODS. Six dental thermoplastic resin materials were evaluated: three polyamide materials (Smile tone, ST; Valplast, VP; and Luciton FRS, LF), two acrylic materials (Acrytone, AT; and Acryshot, AS), and one polypropylene resin material (Unigum, UG). One heat-polymerized acrylic resin (Vertex RS, RS) was chosen for comparison. After obtaining extracts from specimens of the denture resin materials (${\phi}=10$ mm and d=2 mm) under different extraction conditions ($37^{\circ}C$ for 24 hours, $70^{\circ}C$ for 24 hours, and $121^{\circ}C$ for 1 hour), the extracts (50%) or serial dilutions (25%, 12.5%, and 6.25%) in distilled water were co-cultured for 24 hours with immortalized human oral keratinocytes (IHOKs) or mouse fibroblasts (L929s) for the cytotoxicity assay described in ISO 10993. RESULTS. Greater than 70% viability was detected under all test conditions. Significantly lower IHOK and L929 viability was detected in the 50% extract from the VP ($70^{\circ}C$) and AT ($121^{\circ}C$) samples (P<.05), but only L929 showed reduced viability in the 50% and 25% extract from LF ($37^{\circ}C$) (P<.05). CONCLUSION. Extracts obtained from six materials under different extraction conditions ($37^{\circ}C$, $70^{\circ}C$, and $121^{\circ}C$) did not exhibit severe cytotoxicity (less than 70% viability), although their potential risk to oral mucosa at high temperatures should not be ignored.

Study on the Appropriate Spatial unit to Measure Biodiversity Using National Ecosystem Survey Data (전국자연환경조사 자료를 이용한 생물다양성 정량화의 적정공간단위 연구)

  • Lee, Kyung-Il;Hwang, Jin-Hoo;Jang, Rae-Ik;Ryu, Ji-Eun;Jeon, Seong-Woo
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.21 no.5
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    • pp.29-37
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    • 2018
  • Biodiversity refers to the diversity of organisms originating from all sources, including terrestrial ecosystems, aquatic ecosystems, and complex ecosystems and it is considered to be the standard of the area to be preserved and protected. So The Importance of environmental assessment for biodiversity conservation is increasing and International efforts to quantify biodiversity and to develop indices have been made, but there are insufficient researches on the use of biomass databases and their quantification in Korea. In this study, the biodiversity map was constructed using the 3rd National Ecosystem Survey Mammal Data with three spatial units(Administrative Area, 1:5,000 index map, hexagonal lattice). and the difference of map constructed by spatial unit was suggested to help research on quantification and evaluation of biodiversity in the future. As a result of the study, biodiversity index for the same area varied according to the spatial unit and overall average and standard deviation were different too. Therefore it is necessary to utilize appropriate spatial unit considering the suitability and purpose of quantification rather than using specific unit. It also showed the necessity of establishing a standard for biodiversity index as a result of comparative analysis with ecosystem and nature map. Based on this research, comprehensive efforts should be made for the sustainable development of the country through further research and institutional improvement for quantification and evaluation of biodiversity, set standards.

Speaker Detection System for Video Conference (영상회의를 위한 화자 검출 시스템)

  • Lee, Byung-Sun;Ko, Sung-Won;Kwon, Heak-Bong
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.17 no.5
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    • pp.68-79
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    • 2003
  • In this paper, we propose a system that detects the current speaker in multi-speaker video conference by using lip motion. First, the system detects the face and lip area of each of the speakers using face color and shape information. Then, to detect the current speaker, it calculates the change between the current frame and the previous frame. To accomplish this, we used two CCD cameras. One is a general CCD camera, the other is a PTZ camera controlled by RS-232C serial port. The result is a system capable of detecting the face of current speaker in a video feed with more than three people, regardless of orientation of the faces. With this system, it only takes 4 to 5 seconds to zoom in on the speaker from the initial image. Also, it is amore efficient image transmission system for such things as video conference and internet broadcasting because it offers a face area screen at a resolution of 320X240, while at the same time providing a whole background screen.

STUDIES ON THE UTILIZATION OF RICE STRAW BY SHEEP IV. EFFECT OF SOYBEAN MEAL AND BARLEY SUPPLEMENTATION ON EATING AND RUMINATION BEHAVIOR

  • Warly, L.;Fariani, A.;Mawuenyegah, O.P.;Matsui, T.;Fujihara, T.;Harumoto, T.
    • Asian-Australasian Journal of Animal Sciences
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    • v.7 no.2
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    • pp.273-277
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    • 1994
  • A $3{\times}3$ latin square design experiment was conducted to study eating and rumination behavior in sheep fed rice straw (RS) supplemented with soybean meal (SBM) and barley at three different levels of crude protein: low (40 g CP/d, LCP), medium (67 g/d, MCP) and high (94 g/d, HCP). In addition, all the supplements were formulated to contain the same amount of total digestible nutrients (TDN; 275 g). Daily time spent eating and eating rate of RS were not affected by any supplementation. However, time spent ruminating in sheep fed HCP diet was markedly shorter (p<0.05) than in those fed LCP and MCP diets. Rumination index (ruminating time/100 g DM intake) was also significantly reduced (p<0.05) by increasing level of protein supplementation. Although no significant differences were observed, the daily number of rumination periods tended to be lower, while daily number of boli regurgitated was considerably higher in sheep fed HCP diet than in those fed LCP and MCP diets. Increasing level of protein supplementation did not affect the number of chews per bolus, bolus time and rate of chewing during rumination. It is suggested that increasing level of protein supplementation was associated with more effective microbial reduction of rumen digesta particle size and consequently reduced the time spent ruminating.

Anterior Choroidal Artery Aneurysm Surgery : Ischemic Complications and Clinical Outcomes Revisited

  • Lee, Young-Sup;Park, Jaechan
    • Journal of Korean Neurosurgical Society
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    • v.54 no.2
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    • pp.86-92
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    • 2013
  • Objective : Surgical results for anterior choroidal artery (AChA) aneurysms have previously been reported as unsatisfactory due to inadvertent occlusion of the AChA, while the low incidence of AChA aneurysms hampers the accumulation of surgical experience. The authors reviewed their related surgical experience to document the ischemic complications and surgical outcomes. Methods : Identification of the AChA at its origin by rigorous visual scrutiny, careful microdissection, and meticulous clip placement to avoid the AChA origin are all crucial surgical maneuvers. A retrospective review of a surgical series of 62 consecutive cases of an AChA aneurysm between 2004 and 2012 was performed. Results : All patients, except for five (8.1%) with a small residual neck, showed complete aneurysm obliteration in postoperative angiographic evaluations. There was no incidence of procedure-related permanent AChA syndrome or oculomotor nerve palsy, while three (4.8%) patients suffered from transient AChA syndrome. The clinical outcomes [the 3-month modified Rankin Scale (mRS)] of the patients were related to their preoperative World Federation of Neurologic Surgeons (WFNS) grade. As regards the 3-month mRS, significant differences were found between patients with an unruptured aneurysm (WFNS grade 0; n=20), good-grade subarachnoid hemorrhage (WFNS grade 1-3; n=30), and poor-grade subarachnoid hemorrhage (WFNS grade 4-5; n=4). Conclusion : In surgical treatment of AChA aneurysms, a risk of AChA insufficiency can be minimized by taking every precaution to preserve the AChA patency and intraoperative monitoring. In addition, the surgical outcome is primarily determined by the preoperative clinical state.

A New Method for Determination the Parasitic Extrinsic Resistances of MESFETs and HEMTs from the Meaured S-parameters under Active Bias (측정된 S-파라미터에서 MESFET과 HEMT의 기생 저항을 구하는 새로운 방법)

  • 임종식;김병성;남상욱
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.11 no.6
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    • pp.876-885
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    • 2000
  • A new and simple method is presented for determining the parasitic resistances of MESFET and HEMT from the measured S-parameters under normal active bias without depending on additional DC measurements or iteration or optimization process. The presented method is based on the fact that the difference between source resistance(Rs) and drain resistance(Rd) can be obtained from the measured Z-parameters under zero bias condition. It is possible to define the new internal device including intrinsic device and 3 parasitic resistances by elimination the parasitic inductances and capacitances from the measured S-parameters. Three parasitic resistances are calculated easily from the fact that the real parts of Yint,11 and Yint,12 of intrinsic Y-parameters are zero theoretically and the relations between S-,Z-, Y-matrices. The calculated parasitic resistances using the presented method and successively calculated equivalent circuit parameters give modeled S-parameters which are in good agreement with the measured S-parameters up to 400Hz.

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Sequential Percentile Estimation for Sequential Steady-State Simulation (순차적 시뮬레이션을 위한 순차적인 Percentile 추정에 관한 연구)

  • Lee, Jong-Suk;Jeong, Hae-Duck
    • The KIPS Transactions:PartD
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    • v.10D no.6
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    • pp.1025-1032
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    • 2003
  • Percentiles are convenient measures of the entire range of values of simulation outputs. However, unlike means and standard deviations, the observations have to be stored since calculation of percentiles requires several passes through the data. Thus, percentile (PE) requires a large amount of computer storage and computation time. The best possible computation time to sort n observations is (O($nlog_{2}n$)), and memory proportional to n is required to store sorted values in order to find a given order statistic. Several approaches for extimating percentiles in RS(regenerative simulation) and non-RS, which can avoid difficulties of PE, have been proposed in [11, 12, 21]. In this paper, we implemented these three approaches known as : leanear PE, batching PE, spectral $P^2$ PE in the context of sequential steady-state simulation. Numerical results of coverage analysis of these PE approachs are present.

Adsorption and Leaching of cis and frans-Permethrin in the Soil (토양 중 cis 및 trans-Permethrin의 흡착 및 침출)

  • Sam Edward Feagley
    • Journal of Environmental Science International
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    • v.4 no.4
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    • pp.379-386
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    • 1995
  • Permethrin [3-phenox yben zyl(1RS)-cis,tans-3-(2,2-dichloroviny1)-2,2- dimethylcyclopropane carboxylate] insecticides were selected to study adsorption and leaching potentials related to pollution on Commerce silty clay loam soil near Baton Rouge, Louisiana, USA. GLC-ECD chromatogram of permethrin included 32.5 % of cis-pemehin and 67.4 % of trans-permethrin. Extraction efficiencies of is and trmu-pemetun were 92.5 % and 92.3 % in fortified water, respectively and 85.9 % and 88.8 % in fortified soil, respectively. At a 1:10 moi]/water ratio,the Koc values for sis and fan isomers of permethrin were 938 and 877, respectively. Leaching of permethrin was evaluated in soil columns$(5.4 cm i.d. \times 26 cm length)$. Total recoveries of the permethrin applied to the soil column were $84.5\pm3.1%$. When the soil columns were leached with three pore volumes of water, the distributions of cis-permethrin leached were 6.10 % and 0.07 % of amount applied in the untreated zone soil and leachate water, respectively Trans-pemethrin distributions were 5.20 % in the untreated zone soil and 0.05 % in leachate water. Cis and trans-pemethrin was strongly adsorbed to soil. The results of the study showed the strong relationship between adsorption and leaching. Cis and trans-permethrin to be leached into the groundwater in soils with shallow aquifers were suggested a low leaching potential.

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Design of a BLDC Servo Motor Control System for the Auto Process of Assembly and Supply (자동 조립 및 공급을 위한 BLDC 서보 전동기 제어시스템 설계)

  • Sim, Dong-Seok;Choi, Jung-Keyng
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.16 no.5
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    • pp.1095-1101
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    • 2012
  • This paper presents a design of a BLDC servo motor control system for the auto process of assembly and supply using DSP(Digital Signal Processor) controller and IGBT driver. The assembly and supply auto processing system needs torque, speed, position control of servo motor for variable action. This paper implements those servo control with vector control and space vector PWM(Pulse Width Modulation) technique. As CPU of controller, TMS320F240 DSP was adopted because it has PWM waveform generator, A/D converter, SPI(Serial Peripheral Interface) port and many input/output port etc. This control system consists of 3-level hierarchy structure that main host PC manages three sub DSP system which transfer downward command and are monitoring the states of end servo controllers. Each sub DSP system operates eight BLDC servo controllers which control BLDC motor using DSP and IPM. Between host system and sub DSP communicate with RS-422, between main processor and controller communicate with SPI port.

Effect of nutrient composition in a mixed meal on the postprandial glycemic response in healthy people: a preliminary study

  • Kim, Jiyoung S.;Nam, Kisun;Chung, Sang-Jin
    • Nutrition Research and Practice
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    • v.13 no.2
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    • pp.126-133
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    • 2019
  • BACKGROUND/OBJECTIVES: The glycemic index (GI) is a measure of the postprandial glucose response (PPGR) to food items, and glycemic load (GL) is a measure of the PPGR to the diet. For those who need to maintain a healthy diet, it is beneficial to regulate appropriate levels of blood glucose. In reality, what influences the meal GI or GL depends on the macronutrient composition and the physical chemistry reactions in vivo. Thus, we investigated whether different macronutrients in a meal significantly affect the PPGR and the validity of calculated GI and GL values for mixed meals. SUBJECTS/METHODS: 12 healthy subjects (6 male, 6 female) were recruited at a campus setting, and subjects consumed a total of 6 test meals one by one, each morning between 8:00 and 8:30 am after 12 h of fasting. PPGR was measured after each consumed meal and serial finger pricks were performed at indicated times. Test meals included 1) 68 g oral glucose, 2) 210 g rice, 3) rice plus 170 g egg white (RE), 4) rice plus 200 g bean sprouts (RS), 5) rice plus 10 g oil (RO), and 6) rice plus, egg white, bean sprouts, and oil (RESO). The incremental area under the curve (iAUC) was calculated to assess the PPGR. Mixed meal GI and GL values were calculated based on the nutrients the subjects consumed in each of the test meals. RESULTS: The iAUC for all meals containing two macronutrients (RS, RO, or RE) were not significantly different from the rice iAUC, whereas, the RESO iAUC ($2,237.5{\pm}264.9$) was significantly lower (P < 0.05). The RESO meal's calculated GI and GL values were different from the actual GI and GL values measured from the study subjects (P < 0.05). CONCLUSIONS: The mixed meal containing three macronutrients (RESO) decreased the PPGR in healthy individuals, leading to significantly lower actual GI and GL values than those derived by nutrient-based calculations. Thus, consuming various macronutrient containing meals is beneficial in regulating PPGR.