• Polymer(Korea)
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• v.32 no.5
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• pp.409-414
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• 2008

The fabrication of gelatin nanofibers by electro spinning has been examined using the TFE/DW co-solvent system. It has been found that no beads-on-string structure was formed for the solution containing ionic salts. The resulting fibers exhibited a uniform diameter ranging from 110 to 125 nm. As the concentration of ionic salts increases, the beads become smaller and more spindle like, due to the increase of viscosity and conductivity. The addition of ionic salts induces a higher charge density on the surface of ejected jet during spinning, leading that higher elongation forces are applied to the jet. The higher enhancement of viscosity and conductivity was observed in gelatin solutions by the use of divalent salt. However, the concentration of ionic salts scarcely affected the variation of fiber diameter. While very low crystallinity was observed from XRD pattern for the sample containing no ionic salt, which increased with increasing the concentration of ionic salts.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.47 no.5
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• pp.360-364
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• 2021

Objectives: The purpose of this study was to evaluate the clinical and radiographic characteristics of idiopathic bone cavity (IBC) to determine the effect of surgical intervention on the process of healing. Materials and Methods: All cases diagnosed with IBC during the period of 2011 to 2020 at our Department of Oral and Maxillofacial Surgery were searched. Ninety cases were retrieved. The features evaluated were sex, age, contour of the lesion, number of teeth involved, site, history of trauma, and postoperative healing pattern. The significance of differences was assessed by Mann-Whitney U test and chi-square test. Results: The female:male ratio showed no predilection toward either sex (0.9:0.8). The mean age of the collected sample was 22.05±14.38 years, and the age ranged from 10 to 58 years. All cases presented in the mandible and showed well-circumscribed radiolucency. Margins were either scalloped or round in shape, and the size varied from one tooth to six teeth involvement. Seventy cases involved three or fewer roots. Three cases showed bilateral lesion. Four cases had a history of trauma at the area of the lesion. Fifty-one cases were followed for six months after surgery, and all showed increased bone density at the lesion. Conclusion: There is no definitive radiological or clinical feature of IBC. Considering the diversity of clinical and radiological features, such a diagnosis relies primarily on surgical findings of an empty bone cavity with no epithelial lining. Our data suggest that surgical intervention be the first choice of treatment as opposed to observation.

• Animal Bioscience
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• v.34 no.5
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• pp.789-800
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• 2021

Objective: Conservation and genetic improvement of cattle breeds require information about genetic diversity and population structure of the cattle. In this study, we investigated the genetic diversity and population structure of the three cattle breeds in the Korean peninsula. Methods: Jeju Black, Hanwoo, Holstein cattle in Korea, together with six foreign breeds were examined. Genetic diversity within the cattle breeds was analyzed with minor allele frequency (MAF), observed and expected heterozygosity (HO and HE), inbreeding coefficient (FIS) and past effective population size. Molecular variance and population structure between the nine breeds were analyzed using a model-based clustering method. Genetic distances between breeds were evaluated with Nei's genetic distance and Weir and Cockerham's FST. Results: Our results revealed that Jeju Black cattle had lowest level of heterozygosity (HE = 0.21) among the studied taurine breeds, and an average MAF of 0.16. The level of inbreeding was -0.076 for Jeju Black, while -0.018 to -0.118 for the other breeds. Principle component analysis and neighbor-joining tree showed a clear separation of Jeju Black cattle from other local (Hanwoo and Japanese cattle) and taurine/indicine cattle breeds in evolutionary process, and a distinct pattern of admixture of Jeju Black cattle having no clustering with other studied populations. The FST value between Jeju Black cattle and Hanwoo was 0.106, which was lowest across the pair of breeds ranging from 0.161 to 0.274, indicating some degree of genetic closeness of Jeju Black cattle with Hanwoo. The past effective population size of Jeju Black cattle was very small, i.e. 38 in 13 generation ago, whereas 209 for Hanwoo. Conclusion: This study indicates genetic uniqueness of Jeju Black cattle. However, a small effective population size of Jeju Black cattle indicates the requirement for an implementation of a sustainable breeding policy to increase the population for genetic improvement and future conservation.

• Journal of Korean Medicine Rehabilitation
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• v.31 no.2
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• pp.49-55
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• 2021

Objectives The impact of social and economic losses on society due to the occurrence of osteoporosis patients is serious. The purpose of this study is to identify the types and effects of herbal medicine for osteoporosis and osteopenia. Methods We will investigate 8 online databases (MEDLINE/PubMed, Cochrane library, EMbase, China National Knowledge Infrastructure [CNKI], J-stage, National Digital Science Library [NDSL], Research Information Sharing Service [RISS], Koreanstudies Information Service System [KISS]) without language, publication date limitation for the clinical study of herbal medicine for osteoporosis and osteopenia published between the start of the database and 2021. The frequency, duration and pattern of the any type of herbal medicine utilization will be analyzed. Results Randomized controlled trials about herbal medicine or herbal medicine extracts for osteoporosis and osteopenia should be included in the study. Cochrane risk in bias tools will be used to evaluate the methodological quality of the study. A risk ratio or mean difference with a 95% confidence interval will show the effects of herbal medicine or herbal medicine extracts for osteoporosis and osteopenia. Conclusions The results of the systematic review will reflect the current status of herbal medicine treatment for osteoporosis and osteopenia, and it can be expected to verify the validity of the effectiveness, and provide it as a basic data for the use of herbal medicine in clinical utilization.

• Smart Structures and Systems
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• v.23 no.1
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• pp.81-90
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• 2019

The shear behavior of soil-concrete interface is mainly affected by the surface roughness of the two contact surfaces. The present research emphasizes on investigating the effect of roughness of soil-concrete interface on the interface shear behavior in two-layered laboratory testing samples. In these specially prepared samples, clay silt layer with density of $2027kg/m^3$ was selected to be in contact a concrete layer for simplifying the laboratory testing. The particle size testing and direct shear tests are performed to determine the appropriate particles sizes and their shear strength properties such as cohesion and friction angle. Then, the surface undulations in form of teeth are provided on the surfaces of both concrete and soil layers in different testing carried out on these mixed specimens. The soil-concrete samples are prepared in form of cubes of 10*10*30 cm. in dimension. The undulations (inter-surface roughness) are provided in form of one tooth or two teeth having angles $15^{\circ}$ and $30^{\circ}$, respectively. Several direct shear tests were carried out under four different normal loads of 80, 150, 300 and 500 KPa with a constant displacement rate of 0.02 mm/min. These testing results show that the shear failure mechanism is affected by the tooth number, the roughness angle and the applied normal stress on the sample. The teeth are sheared from the base under low normal load while the oblique cracks may lead to a failure under a higher normal load. As the number of teeth increase the shear strength of the sample also increases. When the tooth roughness angle increases a wider portion of the tooth base will be failed which means the shear strength of the sample is increased.

• Journal of Ocean Engineering and Technology
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• v.35 no.1
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• pp.50-58
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• 2021

The demand for eco-friendly energy is expected to increase due to the recently strengthened environmental regulations. In particular, the flow inside the pipe used in a cargo handling system (CHS) or fuel gas supply system (FGSS) of hydrogen transport ships and hydrogen-powered ships exhibits a very complex pattern of multiphase-thermal flow, including the boiling phenomenon and high accuracy analysis is required concerning safety. In this study, a feasibility study applying the boiling model was conducted to analyze the multiphase-thermal flow in the pipe considering the phase change. Two types of boiling models were employed and compared to implement the subcooled boiling phenomenon in nucleate boiling numerically. One was the "Rohsenow boiling model", which is the most commonly used one among the VOF (Volume-of-Fluid) boiling models under the Eulerian-Eulerian framework. The other was the "wall boiling model", which is suitable for nucleate boiling among the Eulerian multiphase models. Moreover, a comparative study was conducted by combining the nucleate site density and bubble departure diameter model that could influence the accuracy of the wall boiling model. A comparison of the Rohsenow boiling and the wall boiling models showed that the wall boiling model relatively well represented the process of bubble formation and development, even though more computation time was consumed. Among the combination of models used in the wall boiling model, the simulation results were affected significantly by the bubble departure diameter model, which had a very close relationship with the grid size. The present results are expected to provide useful information for identifying the characteristics of various parameters of the boiling model used in CFD simulations of multiphase-thermalflow, including phase change and selecting the appropriate parameters.

• Tunnel and Underground Space
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• v.31 no.1
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• pp.66-81
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• 2021

The effects of directional fracture tensor components and first invariant of fracture tensor on deformation moduli and shear moduli of fractured rock masses is analyzed based on regression analysis performed between 3-D fracture tensor parameters and deformability of DFN blocks. Using one or two deterministic joint sets, a total of 224 3-D discrete fracture network (DFN) cube blocks were generated with various configurations of deterministic density and probabilistic size distribution. The fracture tensor parameters were calculated for each generated DFN systems. Also, deformability moduli with respect to three perpendicular direction of the DFN cube blocks were estimated based on distinct element method. The larger the first invariant of fracture tensor, the smaller the values for the deformability moduli of the DFN blocks. These deformability properties present an asymptotic pattern above the certain threshold. It is found that power-law function describes the relationship between the directional deformability moduli and the corresponding fracture tensor components estimated in same direction.

• Advances in nano research
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• v.10 no.3
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• pp.221-234
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• 2021

During the previous few years, phenomenon of bioconvection along with the use of nanoparticles showed large number of applications in technological and industrial field. This paper analyzed the bioconvection phenomenon in magnetohydrodynamic boundary layer flow of a Powell-Eyring nanoliquid past a stretchable cylinder with Cattaneo-Christov heat flux. In addition, the impacts of chemical reaction and heat generation/absorption parameter are considered. By the use of appropriate transformation, the governing PDEs (nonlinear) have been transformed and formulated into nonlinear ODEs. The resulting nonlinear ODEs subjected to relevant boundary conditions are solved analytically through homotopy analysis method which is programmed in Mathematica software. Graphical and numerical results versus physical quantities like velocity, temperature, concentration and motile microorganism are investigated under the impact of physical parameters. It is noted that velocity profile enhances as the curvature parameter A and Eyring-Powell fluid parameter M increases but a decline manner for large values of buoyancy ratio parameter Nr and bio-convection Rayleigh number Rb. In the presence of Prandtl number Pr, Eyring-Powell fluid parameter M and heat absorption parameter ��, temperature profile decreases. Nano particle concentration profile increases for increasing values of magnetic parameter Ha and thermophoresis parameter Nt. The motile density profile has revealed a decrement pattern for higher values of bio-convection Lewis number Lb and bio-convection peclet number Pe. This study may find uses in bio-nano coolant systems, advance nanomechanical bio-convection energy conversion equipment's, etc.

• Korean Journal of Pharmacognosy
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• v.51 no.4
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• pp.332-339
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• 2020

Lentinus edodes (LE) is the first medicinal macrofungus to enter the realm of modern biotechnology. Lentinus edodes is well-known to have anti-tumor, anti-inflammatory, and immunomodulatory effects. In this study, osteoporosis was induced by ovariectomy in female rats, and the prevention and treatment efficacy of the climacteric disease the postmenopausal type I pattern was examined using the experimental substance. Female rats were either sham-operated (sham; n = 5) or surgically ovariectomized (OVX; five animals per group) and then administered to OVX control, raloxifene hydrochloride 1 mg/kg/day, or LE (20 and 200 mg/kg/day) for 12 weeks. LE treatment suppressed the ovariectomy-induced reduction of bone mineral density in the entire tibia as well as its metaphysis with a decrease of serum osteocalcin and interleukin-6 levels. In addition, LE is suggested to elevate the serum levels of progesterone hormones and prevent bone loss in ovariectomized rats. In conclusion, LE 200 mg/kg/day may have inhibitory effects on osteoporosis in OVX rats.

• Nutrition Research and Practice
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• v.15 no.1
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• pp.66-79
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• 2021

BACKGROUND/OBJECTIVES: This study investigated gender and age differences in nutrient intake and dietary quality of people eating alone. SUBJECTS/METHODS: From Korean National Health and Nutrition Examination Survey 2013-2016 data, 2,305 adults aged 20 years and older that ate meals alone were included in this study. Their energy and nutrients intakes, as well as their nutrient adequacy ratio (NAR), mean adequacy ratio (MAR), and index of nutritional quality (INQ) were analyzed. Food group consumption pattern, dietary variety score (DVS), dietary diversity score (DDS) were also analyzed. All data were compared among gender and age groups. RESULTS: Men consumed more energy and nutrients than women, except for vitamin C, and the NARs showed similar gender differences. The INQs of 4 nutrients (calcium, vitamin A, vitamin C, and riboflavin) were lower than 1.0 in men, whereas only the calcium INQ was lower than 1.0 in women. Men had a lower DDS (3.6) than women (3.9) (P < 0.001) and had more 'undesirable' food group consumption patterns than women (P < 0.001). The intakes of calcium, vitamin A, and vitamin C were relatively low in the young-aged group (INQs less than 1.0). In the old-aged group, the MAR level was relatively low, and the INQs of calcium, riboflavin, and niacin were below 1.0. The old-aged group consumed more menu items, but their DVS was the lowest. CONCLUSIONS: Compared to women, the dietary quality and food diversity among men were poorer. There were poorer quality and diversity patterns in the young-aged group compared to those of the older groups. An overall low intake of nutrients and the low nutrient density of meals were the main dietary problems among the old-aged group who eat alone. Therefore, men, particularly young- and old-aged, need to be prioritized in nutritional policies directed toward those who eat alone.