• Proceedings of the KOSOMBE Conference
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• v.1997 no.11
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• pp.263-266
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• 1997

Three dimensional numerical model based on the finite element method(FEM) were developed to predict the mechanical behavior of hip implants. The purpose of this study is to investigate the stress distribution of two types of cementless total hip replacement femoral component -a straight stem and a curved stem, and to compare their effect on the stress shielding between two types by three dimensional finite element method. The authors analyzed von Mises stress in the cortex & stem and compared the stress between the straight and the curved stem. In comparison of stresses between two different design of femoral stem, there was 25% more decrease of stress in straight stem than curved stem in the medial cortex at proximal region. The straight stem had consistently much lower stresses than the curved stem throughout the whole medial cortex with maximum 70% reduction of stress. However, there was little change in stress between nature and 2 implanted femur throughout the lateral cortex. Stress of femoral stem was much higher in the straight stem than the curved stem up to 60%. The straight stem had more chance of stress shielding and a risk of fatigue fracture of the stem compared with the curved stem in noncement hip arthroplasty. In design of femoral stem still we have to consider to develop design to distribute more even stress on the proximal medial cortex.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.05
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• pp.245-248
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• 1997

Excessive stress on the bone-stem interface may cause local micromotion that could produce midthigh pain, interface bone resorption and prevent bony ingrowth. It is important for clinician and prosthetic designer to develop an understanding of the load transfer mechanism, its associated stress pattern and its relationships with the particular mechanical characteristics of the femoral stem designs. Finite element method (FEM) is preeminently suited to provide information in this respect. The authors developed 3-dimensional numerical finite element models implanted with the straight stem which is composed of total 1170 elements of 8 nodes and with the curved stem which is composed of total 885 elements of 8 node, and analysed the relative micromotions between the straight stem and the curved stem in immediate postoperative stage of an uncemented total hip replacement in load simulating the single leg stance. The results showed that the rotational displacement was occupied over 90% of total micromotion in both types of stem and was peak at the proximal medial portion of the stem, but markedly less distally. The curved stem was more stable especially in terms of rotational stability. It is recommended that surgeons do not allow the patient weight bearing until bony ingrowth was achieved. In the future more attention should be drawn to increase initial rotational stability of the two types of femoral stem to prevent loosening from excessive micromotion.

• International Journal of Ocean System Engineering
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• v.3 no.3
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• pp.152-157
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• 2013

This study, a new concept design of the stem and aims to determine the suitability of various carbon/PEEK composite designs for artificial hip joints. Shear stress tested with alternative materials of the Ti-based stem for artificial hip joints. In addition, FEA is conducted according to the fiber ply orientation and the load condition for carbon/PEEK composites. The stem shape of two types was designed through the shape normal of the femur. Multidirectional load cases were used for each FEA model. In the case of general shape, the results show that the stress of ply orientation case II was lower than for cases I and III. On the other hand, in the case of the curved shape, ply orientation case I was lowest. In the case of the Ti stem, the stress of the curved shape was 18% lower than the general shape.

• Journal of Bio-Environment Control
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• v.26 no.3
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• pp.215-220
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• 2017

This study was conducted to improve the insufficiency of fruit vegetable grafting system developed by National Institute of Agricultural Sciences, Rural Development Administration. When the rotary blade cut the stem of scions and rootstocks, the grafting failure at curved cutting surfaces happened. The cutting depth of a tomato seedling by a rotated cutter was calculated 0.11 mm even when the cutting arm length and the maximum stem diameter were 50 mm and 5 mm, respectively. Mathematical analysis and high-speed photography showed that there was no problem by cutting in straight the stem of scions and rootstocks. The compression test of seedling stems to design the optimal shape of gripper showed that stems were not completely restored when they were compressed above 0.8 mm and 0.6 mm in case of rootstocks and scion, respectively. This study found that the bending angle of stem of tomato seedlings at the grafting period was 10 degree on average. The optimal gripper finger was the edge finger type which could be precisely set center point by adjusting the distance between fingers. In addition, it was found that most of seedling could be grasped without damage when the finger-to-finger distances is set to 2.5 mm for scion and 3.0 mm for rootstocks and finger are coated by 1 mm-thick flexible material.

• Mycobiology
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• v.42 no.2
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• pp.206-209
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• 2014

In this study, we identified the causative agent of stem-end rot in potatoes that were grown in Gangwon alpine areas of Korea in 2013. The disease symptoms included appearance of slightly sunken circular lesion with corky rot on the potato surface at the stem-end portion. The fungal species isolated from the infected potatoes were grown on potato dextrose agar and produced white aerial mycelia with dark violet pigments. The conidiophores were branched and monophialidic. The microconidia had ellipsoidal to cylindrical shapes and ranged from $2.6{\sim}11.4{\times}1.9{\sim}3.5{\mu}m$ in size. The macroconidia ranged from $12.7{\sim}24.7{\times}2.7{\sim}3.6{\mu}m$ in size and had slightly curved or fusiform shape with 2 to 5 septate. Chlamydospores ranged from $6.1{\sim}8.1{\times}5.7{\sim}8.3{\mu}m$ in size and were present singly or in pairs. The causal agent of potato stem-end rot was identified as Fusarium oxysporum by morphological characterization and by sequencing the internal transcribed spacer (ITS1 and ITS4) regions of rRNA. Artificial inoculation of the pathogen resulted in development of disease symptoms and the re-isolated pathogen showed characteristics of F. oxysporum. To the best of our knowledge, this is the first study to report that potato stem-end rot is caused by F. oxysporum in Korea.

• The Plant Pathology Journal
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• v.16 no.4
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• pp.242-245
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• 2000

In 1999 and 2000, a rot of graft-cacti including Hylocereus trigonus (three-angled cactus), Gymnocalycium mihanovichii, and Chamaecereus silvestrii occurred in several greenhouses in major cactus-growing areas of Korea. Typical symptoms included a moist, light brown rot or a watery rot of the stems. A Colletotrichum sp. was isolated from the lesions. The fungus formed dark gray, dense or floccose colonies on potato dextrose agar, frequently forming many light pink acervuli often surrounded with setae. The hyaline, cylindrical conidia were one-celled with round ends. Appressoria were mostly semicircular or clavate. Thin-walled asci contained eight, one-celled, hyaline ascospores (biseriate in ascus). Ascopspores were strainht or curved, ellipsoidal or subcylindrical. Based on these characteristics, the fungus was identified as Glomerlla cingulata (anamorph : C. gloeosporioides). Wound inoculation of basal stems of the cactus by the mycelial plugs or conidia produced symptoms identical to those described above. Various cactus species were compared in susceptibility using stem disc inoculation. Cereus tetragonus, Eriocereus jusbertii, Myrtillocactus geomentrizans, and three-angled cacti from Mexico and Taiwan were susceptible, but C. peruvianus (Peruvian apple cactus) and Harrisia tortuosa not. This is the first report of G. cingulata causing stem rot of graft-cactus in Korea.

• Journal of the Korean Society of Marine Environment & Safety
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• v.2 no.S1
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• pp.63-73
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• 1996

The assesment of the safety of ship's transit in a curved narrow channl consists of the maneuvering safety determined by the chance of running aground, the maneuvering difficulty determined by shop's workload, and shiphandler's subjective evaluation. In this study to examine the correlation between shiphandler's subjectice evaluation and the maneuvering risk, the real-time and full-mission shiphandling simulator in the Korean Marine Training & Research Institutes(KMTRI) was utilized. In the conning bridge of the shiphandling simulator, 50 experienced masters conducted masters conducted the modeled vessel of 60,000 deadweight tonnage along the designed channel under 3 different envrinmental conditions. The findings were as follows: (1) The frequencies of stress levels, work difficulties, vessel controllability and overall workload of shiphandlers are similar irrespective of environmental conditions and they are able to be represented as shiphandler's subjective evaluation. (2) It is possible to assess and analyze theoretically the correlation between the shiphandler's subjective ecaluation and maneuvering risk each environmental cindition by quantifying the data obtioned from the tests. The results are as follows: ① As the degree of maneuvering risk increases, the shiphandler's subjective evaluation increases sharply near the curvature area of the desgined channel. ② In the area of the curvature of the designed channel, maneuvering risk increases sharply with the danger of running aground under the environmental condition of current and wind comung from the stem.

• Journal of Korean Society of Forest Science
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• v.109 no.1
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• pp.62-71
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• 2020

With the aim of restoring slow-moving landslide areas, this study collected fundamental data from tree-ring analysis of curved trees in these areas. We collected both upper and lower stem disks to measure the azimuth angles of six trees with growth curvature caused by tension cracks. Additionally, we analyzed various factors in the slow moving landslide area. The geological strata and main constitutive rocks in the study area were anorthosite-formed in the Precambrian period; moreover, there were no intrusive rocks, other geological strata, geological folds, or faults. The talus with weathered rocks was distributed in the upper zone of the slow-moving landslide area. According to annual-ring analysis of curved trees and terrain analysis by satellite imagery, slow-moving landslide occurred from the top to the bottom end of the slope between 1999 and 2011. There was a significant relationship (P < 0.01) between the azimuth angle of cracks caused by the slow-moving landslide and the angle of the curved trees. These results suggest that the occurrence of slow-moving landslides could be confirmed through analysis of annual-rings of curved trees, underground water levels, and terrain (by satellite imagery).

• Research in Plant Disease
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• v.8 no.4
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• pp.224-227
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• 2002

From the necrotic stem of aquaculture Dracaena for living room decoration, we observed conidia on acervuli with occasional setae and perithecia in vivo. Morphological characters were; acervuli, dark brown and 300-500 ${\mu}{\textrm}{m}$ in diameter; conidia, hyaline, aseptate, cylindrical to slightly ellipsoid with rounded apex and narrow truncate base on phialidic conidiophores, 12.5-17.5 ${\mu}{\textrm}{m}$; setae, variable in length 1-4 septate, slightly swollen at the base and tapered to the apex, 200 ${\mu}{\textrm}{m}$; appressoria, dark brown ovate to obovate irregular 5-12.5 ${\mu}{\textrm}{m}$, perithecia on decayed stem, globose, dark brown and black 85-300 ${\mu}{\textrm}{m}$; asci 8 spored, clavate to cylindrical; 50-62.5$\times$8-10 ${\mu}{\textrm}{m}$; ascospores, oval to fusiform, sometimes slightly curved, aseptate, hyaline. Above characteristics were also confirmed in vitro. Colletotrichum state of this fungus was also compared with C. lindemuthianum and C. musae in terms of morphology of conidia and setae and growth on PDA etc. This fungus was identified as Glomerella cingulata(Stonem.) Spaulding & Schrenk(Colletotrichum gloeosporioides(Penz. Sacc.).

• Mycobiology
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• v.45 no.3
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• pp.226-231
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• 2017

Coprinopsis cinerea was employed to investigate the fungal response to gravity. Mycelium growth revealed a consistent growth pattern, irrespective of the direction of gravity (i.e., horizontal vs. perpendicular). However, the fruiting body grew in the direction opposite to that of gravity once the primordia had formed. For the proteomic analysis, only curved-stem samples were used. Fifty-one proteins were identified and classified into 13 groups according to function. The major functional groups were hydrolases and transferases (16%), signal transduction (15%), oxidoreductases and isomerases (11%), carbohydrate metabolism (9%), and transport (5%). To the best of our knowledge, this is the first report on a proteomic approach to evaluate the molecular response of C. cinerea to gravity.