• Journal of Periodontal and Implant Science
• /
• v.36 no.2
• /
• pp.531-554
• /
• 2006

Oral implants must fulfill certain criteria arising from special demands of function, which include biocompatibility, adequate mechanical strength, optimum soft and hard tissue integration, and transmission of functional forces to bone within physiological limits. And one of the critical elements influencing the long-term uncompromise functioning of oral implants is load distribution at the implant- bone interface, Factors that affect the load transfer at the bone-implant interface include the type of loading, material properties of the implant and prosthesis, implant geometry, surface structure, quality and quantity of the surrounding bone, and nature of the bone-implant interface. To understand the biomechanical behavior of dental implants, validation of stress and strain measurements is required. The finite element analysis (FEA) has been applied to the dental implant field to predict stress distribution patterns in the implant-bone interface by comparison of various implant designs. This method offers the advantage of solving complex structural problems by dividing them into smaller and simpler interrelated sections by using mathematical techniques. The purpose of this study was to evaluate the stresses induced around the implants in bone using FEA, A 3D FEA computer software (SOLIDWORKS 2004, DASSO SYSTEM, France) was used for the analysis of clinical simulations. Two types (external and internal) of implants of 4.1 mm diameter, 12.0 mm length were buried in 4 types of bone modeled. Vertical and oblique forces of lOON were applied on the center of the abutment, and the values of von Mises equivalent stress at the implant-bone interface were computed. The results showed that von Mises stresses at the marginal. bone were higher under oblique load than under vertical load, and the stresses were higher at the lingual marginal bone than at the buccal marginal bone under oblique load. Under vertical and oblique load, the stress in type I, II, III bone was found to be the highest at the marginal bone and the lowest at the bone around apical portions of implant. Higher stresses occurred at the top of the crestal region and lower stresses occurred near the tip of the implant with greater thickness of the cortical shell while high stresses surrounded the fixture apex for type N. The stresses in the crestal region were higher in Model 2 than in Model 1, the stresses near the tip of the implant were higher in Model 1 than Model 2, and Model 2 showed more effective stress distribution than Model.

• Korean journal of food and cookery science
• /
• v.13 no.1
• /
• pp.78-85
• /
• 1997

To determine the optimum coagulants concentrations for preparing soybean-curds, the transmittance of soybean-curd whey using spectrophotometer has been measured. The textural properties of soybean-curds were examined by texture analyzer and sensory evaluations. The general components, oligosaccharides and amino acids in soybean-curd wheys were analyzed. Protein patterns of soybean-curd wheys comparing with soyflour and soymilk were investigated. By texture analyzer, hardness, cohesiveness, springiness, and gumminess of Cacl$_2$ soybean-curd, MgCl$_2$ soybean-curd were higher than those of CaSO$_4$ soybean-curd and GDL soybean-curd. In the sensory evaluations, CaSO$_4$ soybean-curds and GDL soybean-curds were smoother and moister than others. Glutamic acid and aspartic acid were the first two abundant amino acids in three kinds of soybean-curd wheys, but arginine was the most abundant amino acid in GDL soybean-curd whey. Total sugar content of soybean-curd wheys were about 12-13 g/l, and the main sugars among 5 kinds of sugars were sucrose and raffinose. Electrophoresis using SDS-PAGE showed that glycinin and P-conglycinin, the main proteins of soybean appeared in soy flour and soymilk, and only low molecular weight subunits appeared in soybean-curd wheys.

• Allergy, Asthma & Immunology Research
• /
• v.10 no.6
• /
• pp.614-627
• /
• 2018

Purpose: Asthma is a heterogeneous disease that responds to medications to varying degrees. Cluster analyses have identified several phenotypes and variables related to fixed airway obstruction; however, few longitudinal studies of lung function have been performed on adult asthmatics. We investigated clinical, demographic, and inflammatory factors related to persistent airflow limitation based on lung function trajectories over 1 year. Methods: Serial post-bronchodilator forced expiratory volume (FEV) 1% values were obtained from 1,679 asthmatics who were followed up every 3 months for 1 year. First, a hierarchical cluster analysis was performed using Ward's method to generate a dendrogram for the optimum number of clusters using the complete post-FEV1 sets from 448 subjects. Then, a trajectory cluster analysis of serial post-FEV1 sets was performed using the k-means clustering for the longitudinal data trajectory method. Next, trajectory clustering for the serial post-FEV1 sets of a total of 1,679 asthmatics was performed after imputation of missing post-FEV1 values using regression methods. Results: Trajectories 1 and 2 were associated with normal lung function during the study period, and trajectory 3 was associated with a reversal to normal of the moderately decreased baseline FEV1 within 3 months. Trajectories 4 and 5 were associated with severe asthma with a marked reduction in baseline FEV1. However, the FEV1 associated with trajectory 4 was increased at 3 months, whereas the FEV1 associated with trajectory 5 was persistently disturbed over 1 year. Compared with trajectory 4, trajectory 5 was associated with older asthmatics with less atopy, a lower immunoglobulin E (IgE) level, sputum neutrophilia and higher dosages of oral steroids. In contrast, trajectory 4 was associated with higher sputum and blood eosinophil counts and more frequent exacerbations. Conclusions: Trajectory clustering analysis of FEV1 identified 5 distinct types, representing well-preserved to severely decreased FEV1. Persistent airflow obstruction may be related to non-atopy, a low IgE level, and older age accompanied by neutrophilic inflammation and low baseline FEV1 levels.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.18 no.5
• /
• pp.1-18
• /
• 2019

A short-turn bus is a bus that is operated within a subsection of an existing bus line. Previous studies regarding short-turn buses decided optimal turn-back points for a single bus line rather than a bus network. Also, in-vehicle crowding which has a significant impact on transit convenience was rarely considered. Therefore, this study aimed to develop a methodology to set priorities for the introduction of short-turn buses of bus lines and sections, considering crowding. To achieve this objective, we calculated occupancies and crowding alleviation benefits of existing bus lines overlapping a new short-turn route based on transit card data, before and after the introduction of short-turn strategy. Also, operator and social costs caused by the introduction of short-turn buses were calculated. Those procedures were iterated over bus lines and sections to operate a short-turn service, and a section whose benefit-to-cost ratio (B/C) is the largest in a line was selected to operate a short-turn service in the line. After, priorities of bus lines to introduce short-turn services could be determined based on B/C values, and the optimum total fleet size could be determined when a short-turn strategy is applied in multiple lines.

• Korean Journal of Environment and Ecology
• /
• v.33 no.1
• /
• pp.86-106
• /
• 2019

We investigated the environmental conditions of natural habitats of T. nuda. The species was found on rocky northern hills ($60{\sim}90^{\circ}$) near the stream where the sea level ranges 95~145m. The average annual temperature of the habitats was lower than other places of South Korea. The differences of the lowest and the highest of the year was significantly huge than any other places. Plants were growing at the edge of stream that water reached but not submerged. Most of plants were found in North, Northeast or Northwest. It is suggested that these species require moist and low sunlight for growth. The common vegetation along with the T. nuda includes Mukdenia rossii, Selaginella rossii, Calamagrostis epigeios, and Rhododendron yedoense f. poukhanense. The dominance values and sociability of T. nuda were below 3 in all studied habitats and the variance of the number of individuals among the habitats was very high. As the optimum habitats for the T. nuda are decreasing due to the extreme precipitation patterns. It is also expected that the number of T. nuda will be decreased in the future. Therefore restoration activity in situ or ex situ must be conducted to conserve this valuable plant species.

• Korean Journal of Radiology
• /
• v.23 no.1
• /
• pp.112-123
• /
• 2022

Objective: To investigate the relationship between ¹⁸F-FDG PET/CT semi-quantitative parameters and the International Association for the Study of Lung Cancer, American Thoracic Society/European Respiratory Society (IASLC/ATS/ERS) histopathologic classification, including histological subtypes, proliferation activity, and somatic mutations. Materials and Methods: This retrospective study included 419 patients (150 males, 269 females; median age, 59.0 years; age range, 23.0-84.0 years) who had undergone surgical removal of stage IA-IIIA lung adenocarcinoma and had preoperative PET/CT data of lung tumors. The maximum standardized uptake values (SUVmax), background-subtracted volume (BSV), and background-subtracted lesion activity (BSL) derived from PET/CT were measured. The IASLC/ATS/ERS subtypes, Ki67 score, and epidermal growth factor/anaplastic lymphoma kinase (EGFR/ALK) mutation status were evaluated. The PET/CT semi-quantitative parameters were compared between the tumor subtypes using the Mann-Whitney U test or the Kruskal-Wallis test. The optimum cutoff values of the PET/CT semi-quantitative parameters for distinguishing the IASLC/ATS/ERS subtypes were calculated using receiver operating characteristic curve analysis. The correlation between the PET/CT semi-quantitative parameters and pathological parameters was analyzed using Spearman's correlation. Statistical significance was set at p < 0.05. Results: SUVmax, BSV, and BSL values were significantly higher in invasive adenocarcinoma (IA) than in minimally IA (MIA), and the values were higher in MIA than in adenocarcinoma in situ (AIS) (all p < 0.05). Remarkably, an SUVmax of 0.90 and a BSL of 3.62 were shown to be the optimal cutoff values for differentiating MIA from AIS, manifesting as pure ground-glass nodules with 100% sensitivity and specificity. Metabolic-volumetric parameters (BSV and BSL) were better potential independent factors than metabolic parameters (SUVmax) in differentiating growth patterns. SUVmax and BSL, rather than BSV, were strongly or moderately correlated with Ki67 in most subtypes, except for the micropapillary and solid predominant groups. PET/CT parameters were not correlated with EGFR/ALK mutation status. Conclusion: As noninvasive surrogates, preoperative PET/CT semi-quantitative parameters could imply IASLC/ATS/ERS subtypes and Ki67 index and thus may contribute to improved management of precise surgery and postoperative adjuvant therapy.

• Korean Journal of Environmental Agriculture
• /
• v.25 no.2
• /
• pp.164-169
• /
• 2006

This study was conducted for 10 days from 17 July to 26 July in 2005 to measure the amount of xylem sap flow under short-term variation of soil moisture regimes at -20 kPa, -50 kPa and -80 kPa in eight-year-old 'Fuji'/M.9 apple trees with different fruit loads. Fruit load was adjusted as three different treatments with standard (100%), 1/2 times (50%) and 2 times (200%) on the basis of optimum fruiting number per tree as the standard fruit load of Fuji cultivar. Trees with standard fruit load during the experimental period showed higher xylem sap flow at -50 kPa of soil moisture regimes than those of trees with 1/2 times and 2 times fruit load. Trees with 1/2 times and 2 times fruit load had similar patterns of the diurnal changes of xylem sap flow, vapor pressure deficit (VPD), and maximum evapotranspiration (ETm). However, trees with 2 times fruit load at -50 kPa and -80 kPa of soil moisture regimes produced lower amount of xylem sap flow than ETm. Trees with standard fruit load produced $1.06{\sim}3.93$ L/tree more amount of xylem sap flow than ETm at all soil moisture regimes. But xylem sap flow of tees with 2 times fruit load had 21% lower at -50 kPa and $31{\sim}36%$ lower at -20 kPa and -80 kPa of soil moisture regimes, respectively than that of trees with standard fruit load. Shoot growth and leaf area were significantly the highest in trees with standard fruit load while those of trees with 2 times fruit load recorded significantly lowest. Leaf water potential of trees with standard fruit load was lower than that of trees with 1/2 times and 2 times fruit load. It indicated that tees with standard fruit load had higher water use for transpiration than other treatments and tees with 2 times fruit load received more stress for the transpiration process under low soil moisture regimes. Consequently, 'Fuji'/M.9 apple trees, the fruit load and soil moisture should be maintained optimum to increase xylem sap flow and transpiration during higher growth period.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.15 no.4
• /
• pp.3170-3180
• /
• 1973

This study of the subject will review past and present irrigation development in Korea. Particular attention will be given to water pricing structure and a case study on the purpose of rational operation and management of irrigation water and organizations, and the optimum irrigation water and organizations, and the optimum irrigation water fee inorder to reduce farmers burden and to rationalize the farmland associations management so as to achieve development of the rural environment. In 1971, the reservoir of the Farmland Improvement A sociation (FIA) produced only 775 millison $m^3$ of irrigation water or 77% of planned capacity of 1,015 million $m^3$. It was caused by inefficient maintenance of irrigation facilities; for instance, about 21% of reservoirs, pumping stations and weirs in Korea have been silted by soil erosion which hinder to water production according to an ADC survey. The first Irritation Association was established in 1906, whcih was renamed the Farmland Assoeiation by the Rural Development Enouragement Law in 1970. By the end of 1971, 411,000 ha of rice paddies were under the control of 267 associations nationwide. The average water price assessed by Associations nationwide rose from 790 won per 0.1 ha. in 1966 to 1,886 won in 1971. The annual growth rate was 20%. The highest water price in 1971 was 4,773 won her 0.1 ha. and the lowest was 437 won. This range was caused by differences in debt burden, geographic conditions and management efficiency among the Associations. In 1971, the number of Associations which exceeded the average water price of 1,886 won per 0.1 ha. was 144, or 55.1% of all Association. In determination of water price, there are two principles; one is determined by production cost such as installation cost of irrigation facilities, maintenance cost, management cost and depreciation ect. For instance, the Yong San River Development project was required 33.7 billion won for total construction and maintenance cost is 3.1 billion won for repayment, maintenance and management cost per year. The project produces 590 million $m^3$ of irrigation water annually. Accordingly, the water price per $m^3$ is 5.25 won. The other principle is determined by water value in the crop products and in compared with production of irrigated paddy and non-irrigated paddy. By using this method, water value in compared with paddy rice vs. upland rice(Average of 1967-1971) was 14.15 won per $m^3$ and irrigated paddy vs. non-irrigated paddy was 2.98 won per $m^3$. In contrast the irrigation fee in average association of 1967-1971 was 1.54 won per $m^3$. Accordingly, the current national average irrigation fee(water price) is resonable compared with its water value. In this study, it is found that the ceiling of water price in terms of water value is 2.98 won per $m^3$ or 2,530 won per 0.1 ha. However, in 1971 55% of the associations were above the average of nationwide irrigation fees. which shows the need for rationalization of the Association's management. In connection with rationalization of the Association's management, this study recommends the following matters. (1) Irrigation fee must be assessed according to the amount of water consumption taking intoaccount the farmer's ability. (2) Irrigation fee should be graded according to behefits and crop patterns. (3) Training personnel in the operation and procedures of water management to save O&M costs. (4) Insolvent farmland association should be integrated into larger, sound associations in the same GUN in order to reduce farmers' water cost. (5) The maintenance and repair of existing irrigation facilities is as important as expansion of facilities. (6) Establishment of a new Union of Farmland Association is required to promoted proper maintenance and to protect the huge investment in irrigation facilities by means of technical supervision and guidance.

• Korean Journal of Soil Science and Fertilizer
• /
• v.44 no.3
• /
• pp.502-509
• /
• 2011

It is important to determine optimum soil covering depths for tree survival and growth because soil covering depths for establishing tree planting bases in coastal reclaimed lands are related to the costs for soil collection, transportation and land reclamation. The objectives of this study were carried out to determine optimum soil covering depths for the normal growth of planted trees in a coastal reclaimed land. The study sites were located in Asan National Industrial Complex in Pyeongtaek City, Gyeonggi-do. Four tree species (Pinus thunbergii, Chamaecyparis pisifera, Zelkova serrata, Quercus acutissima) with one hundred eighty trees of each species were planted in various depths of soil covering (no soil covering, 0.5 m, 1.5 m, 2.0 m soil covering treatments) on April 1998, and the tree growth patterns were measured on September 2000. The change of soil properties, tree mortality rate, root collar diameter and height growth were measured from each soil covering depth treatment on September 2000. Soil pH, EC, exchangeable cations ($K^+$, $Na^+$, $Ca^{2+}$, $Mg^{2+}$), anion $Cl^-$, and base saturation increased with decreased soil covering depths. The mortality rates of tree species showed decreased with increased soil covering depths. The height growth of tree species increased with increased soil covering depths. Height growth of Pinus thunbergii was significantly different between the soil covering depth below 0.5m and other three covering depths, while the growth of other species (C. pisifera, Z. serrata, Q. acutissima) was significantly higher in soil covering depths below 1.5 m than in other soil covering depth treatments. The root collar diameter growth of all tree species showed increasing trends with increased soil covering depths. It is recommended to cover the soil depths above 1.5 m to decrease mortality and to stimulate the tree growth of C. pisifera, Z. serrata and Q. acutissima, while P. thunbergii which is a salt tolerate species could be planted in the 1.0 m soil covering depth.

• Journal of Sericultural and Entomological Science
• /
• v.23 no.2
• /
• pp.11-36
• /
• 1982

Forty-nine plant species as additives to silkworm artificial diet and 5 species as cellulose sources for artificial diet were screened for their economic values as feed-resources for the silkworm. Feeding response to artificial diet was tested on 82 silkworm strains. The effect of rearing conditions on feeding response and enzyme activities in the silkworm was investigated. The results were summarized as follows. 1. Seven species out of 49, Vigna sinensis ENDL, Ipomoea vatatas Lamarck, Cyperus anuricus Var. Laxus, Alnus japonica Stendel, Trifolium repens L, Prunus serrulata Lindley. Var, Glycine max L increased feeding response, compared with the basic formula of artificial diet. 2. The economic values of Vigna sinensis ENDL, Ipomoea vatatas Lamarck, Cyperus anuricus Var. Laxus, Ainus japonica Stendel, Cassia tera L, Erigeron canedensis L as feed-resources for artificiale diet were recognized, through feeding experiment during the entire larval stage. 3. Mulberry cellulose showed the best results in rearing and cocoon characteristics. 4. The extent of feeding response varied according to strains and varieties. Varieties in japanese strains showed higher feeding response than those in chinese and european varieties, with considerable variations among a varieties in strains. 5. The begining of 4th instar seems to be a proper time to convert from mulberry to artificial diet, or artificial diet to mulberry, however the middle of 3rd instar seems acceptable. 6. The optimum temperature for artificial diet rearing is 30$^{\circ}C$ during the period of 1st-3rd instar and 28$^{\circ}C$ for 4th-5th instar. 7. Electrophoretic isozyme patterns of esterase and acid phosphatase on agarose gel, as affected by strain. rearing temperature and feed-resources, were observed as follow. (1) Isozyme patterns of mid-gut esterase varied, depending on instar. One or two more isozyme bands were observed in the larvae than feed on the mulberry fed for the artificial diet. (2) A strain, chinese-15 with a higher feeding response, had 1∼2 more bands than chinese-60 with a lower feeding response. (3) Five bands of mid-gut esterase in 3rd and 4th instar larvae reared at 28$^{\circ}C$. and 4 for 3rd instar and 6∼7 for 4th instar larvae at 35$^{\circ}C$ were observed. (4) No similar esterase bands could be found among mid-gut, blood and silkgland. There are five esterase bands in the midgut, one in blood and three in silkgland. (5) There was rather small digerence in acid phosphatase types of mid-gut and blood according to varieties and rearing temperature. No active band was shown in silkgland. In midgut, there was one acid phosphatase band at 3rd instar, two at 4th instar and three at 5th instar. In blood, one active band at 3rd or 4th instar and three bands at 5th inster wire detected.