• International Journal of Fluid Machinery and Systems
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• v.2 no.4
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• pp.353-362
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• 2009

In the process of turbine modernizations, the investigation of the influences of water passage roughness on radial flow machine performance is crucial and validates the efficiency step up between reduced scale model and prototype. This study presents the specific losses per component of a Francis turbine, which are estimated by CFD simulation. Simulations are performed for different water passage surface roughness heights, which represents the equivalent sand grain roughness height. As a result, the boundary layer logarithmic velocity profile still exists for rough walls, but moves closer to the wall. Consequently, the wall friction depends not only on roughness height but also on its shape and distribution. The specific losses are determined by CFD numerical simulations for each component of the prototype, taking into account its own specific sand grain roughness height. The model efficiency step up between reduced scale model and prototype value is finally computed by the assessment of specific losses on prototype and by evaluating specific losses for a reduced scale model with smooth walls. Furthermore, surveys of rough walls of each component were performed during the geometry recovery on the prototype and comparisons are made with experimental data from the EPFL Laboratory for Hydraulic Machines reduced scale model measurements. This study underlines that if rough walls are considered, the CFD approach estimates well the local friction loss coefficient. It is clear that by considering sand grain roughness heights in CFD simulations, its forms a significant part of the global performance estimation. The availability of the efficiency field measurements provides an unique opportunity to assess the CFD method in view of a systematic approach for turbine modernization step up evaluation. Moreover, this paper states that CFD is a very promising tool for future evaluation of turbine performance transposition from the scale model to the prototype.

• Journal of Pharmacopuncture
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• v.19 no.3
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• pp.253-258
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• 2016

Objectives: The goals of this research were to evaluate acute (single-dose) and sub-acute (repeated-dose) toxicity profiles of methanolic extract of Pistacia integerrima J. L. Stewart ex Brandis (PI) for Wistar rats and to assess the safety profile of PI by observing physiological changes, mortality, changes in body weight, the histopathology of body organs, the hematology and the biochemistry of the animals. Methods: The toxicity profile of PI was evaluated using Wistar rats of both sexes. Animals were divided into four groups: Group 1; control group (normal saline), Group 2; PI-1 (250 mg/kg), Group 3; PI-2 (500 mg/kg), Group 4; PL-3 (1,000 mg/kg). An acute-toxicity study in which animals received a single dose of PI extract (2,000 mg/kg) and were then observed for 14 days for changes in skin, fur, eye color, mucous membrane secretions and excretions, gait, posture, and tonic or clonic movements was performed according to guideline 425 of the Organization of Economic and Corporation Development (OECD). In the repeated-dose toxicity study (OECD - 407) animals received a daily dose of PI extract for 28 days (4 weeks). The parameters observed in this study include body weight, hematology and biochemistry of the animals. Results: In the acute toxicity study, no mortalities or changes in behavior were noted in the animals. The repeated-dose toxicity study was also devoid of any toxicity in the animals during the 28 days of testing with PI extract. The extract did not alter- the body weight, hematology or biochemistry of the animals. The methanolic extract of PI was to be found safe to the no-observed-adverse-effect-level (NOAEL) for the single-dose and repeated-dose toxicity tests in rats. Conclusion: The methanolic extract of PI was devoid of toxicity; hence, it can be used for various ayurvedic preparations and treatments of diseases.

• Journal of Animal Reproduction and Biotechnology
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• v.37 no.2
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• pp.136-143
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• 2022

Recent progress has been made to establish intestinal organoids for an in vitro model as a potential alternative to an in vivo system in animals. We previously reported a reliable method for the isolation of intestinal crypts from the small intestine and robust three-dimensional (3D) expansion of intestinal organoids (basal-out) in adult bovines. The present study aimed to establish next-generation intestinal organoids for practical applications in disease modeling-based host-pathogen interactions and feed efficiency measurements. In this study, we developed a rapid and convenient method for the efficient generation of intestinal organoids through the modulation of the Wnt signaling pathway and continuous apical-out intestinal organoids. Remarkably, the intestinal epithelium only takes 3-4 days to undergo CHIR (1 µM) treatment as a Wnt activator, which is much shorter than that required for spontaneous differentiation (7 days). Subsequently, we successfully established an apical-out bovine intestinal organoid culture system through suspension culture without Matrigel matrix, indicating an apical-out membrane on the surface. Collectively, these results demonstrate the efficient generation and next-generation of bovine intestinal organoids and will facilitate their potential use for various purposes, such as disease modeling, in the field of animal biotechnology.

• Journal of Periodontal and Implant Science
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• v.52 no.6
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• pp.466-478
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• 2022

Purpose: Coronally advanced split-or full-thickness (CAST or CAFT) flaps in combination with subepithelial connective tissue grafts (SCTGs) are commonly used in root-coverage procedures despite postoperative pain and bleeding from the graft donor site. Therefore, the modified vestibular incision subperiosteal tunnel access procedure (VISTAX) uses a novel collagen matrix (VCMX) instead of autogenous tissue to address the limitations associated with autogenous tissue grafting. This retrospective study compared the clinical outcomes of VISTAX to the results obtained after using a CAST or CAFT flap in combination with SCTG for root coverage. Methods: Patients with single or multiple adjacent recession I/II defects were included, with 10 subjects each in the VISTAX, CAFT, and CAST groups. Defect coverage, keratinized tissue width, esthetic scores, and patients' perceived pain and dentinal hypersensitivity (visual analogue scale [VAS]) were assessed at baseline, 3 months, and 6 months. Results: All surgical techniques significantly reduced gingival recession (P<0.0001). Defect coverage, esthetic appearance, and the reduction in dentinal hypersensitivity were comparable. However, the VAS scores for pain were significantly lower in the VISTAX group than in the CAFT and CAST groups, which had similar scores (P<0.05). Furthermore, the clinical results of VISTAX and CAFT/CAST generally remained stable at 6 months. Conclusions: The clinical outcomes of VISTAX, CAFT, and CAST were comparable. However, patients perceived significantly less pain after VISTAX, indicating a potentially higher patient acceptance of the procedure. A prospective trial with a longer follow-up period and a larger sample size should therefore evaluate VISTAX further.

• 대한예방의학회:학술대회논문집
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• 1994.02a
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• pp.469-475
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• 1994

This paper presents a brief survey of current methodology available for quantitative risk assessment of environmental carcinogens. Four current models for low-dose extrapolation are reviewed. Current problems and controversies and possible options in doing quantitative risk assessments based on chronic animal studies are discussed.

• Proceedings of the Korean Information Science Society Conference
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• 2010.11a
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• pp.1-2
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• 2010

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2004.05a
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• pp.237-238
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• 2004

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1998.10a
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• pp.267-267
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• 1998

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1279-1282
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• 2008

Organic field effect transistors are excellent candidates for addressing and local amplification elements for large area electronics because they can easily be processed at low temperatures on essentially arbitrary substrates. We present the use of these devices in an active matrix photodetector and as a buffer for a strain sensor.

• Journal of Ginseng Research
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• v.28 no.2
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• pp.75-77
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• 2004

American ginseng (Panax quinquefolium L.) is one of the most widely used medicinal herbs in the world. It is indigenous to North America and was used by native North Americans long before the arrival of Europeans in the New World.(omitted)