• Title/Summary/Keyword: skeletal structures

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Design of lightweight mansard portal frames

  • Morales-Rodriguez, P.A.;Lopez-Perales, J.A.;Moreno, M.C. Serna
    • Steel and Composite Structures
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    • v.24 no.3
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    • pp.277-285
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    • 2017
  • Single-storey industrial buildings are one of the most often type of structures built among various skeletal framed steel constructions. These metallic buildings offer an exceptional opportunity to minimise the material employed, contributing to a more sustainable construction. In particular, the mansard portal frame is a typology made up of broken beams that involves different lengths and discontinuous slopes. This study aims the weight reduction of the standard mansard portal frame with design purposes by means of varying four parameters: the kink position, the eaves-apex slope, the span and the columns height. In this work, we suggest some guidelines that can improve the economical competitive capabilities of their structural design. In all the cases analysed, the joints of the portal frame are placed over the theoretical non-funicular shape to uniform loads. This allows reducing the bending moment and the shear force, but increasing the axial force. In addition, the performance of mansard and typical pitched portal frames submitted to the same boundary conditions is compared in terms of efficiency in the use of steel. In the large majority of the cases, mansard typologies are lighter than the common pitched frames and, hence, more economical.

An Image-guided Radiosurgery for the Treatment of Metastatic Bone Tumors using the CyberKnife Robotic System

  • Cho, Chul-Koo
    • The Journal of the Korean bone and joint tumor society
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    • v.13 no.1
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    • pp.14-21
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    • 2007
  • Bone is a common site for metastatic spread from many kinds of malignancies. The morbidity associated with this metastatic spread can be significant, including severe pain. When it comes to spinal metastasis, occupying nearly 40% of skeletal metastases, the risks of complications, such as vertebral body collapse, nerve root impingement, or spinal cord compression, are also significant. Because of the necessity of preserving the integrity of the spinal column and the proximity of critical structures, surgical treatment has limitations when durable local control is desired. Radiotherapy, therefore, is often used as an adjunct treatment or as a sole treatment. A considerable limitation of standard radiotherapy is the reported recurrence rate or ineffective palliation of pain, either clinically or symptomatically. This may be due to limited radiation doses to tumor itself because of the proximity of critical structures. CyberKnife is an image-guided robotic radiosurgical system. The image guidance system includes a kilovoltage X-ray imaging source and amorphous silica detectors. The radiation delivery device is a mobile X-band linear accelerator (6 MV) mounted on a robotic arm. Highly conformal fields and hypofractionated radiotherapy schedules are increasingly being used as a means to achieve biologic dose escalation for body tumors. Therefore, we can give much higher doses to the targeted tumor volume with minimizing doses to the surrounding critical structures, resulting in more effective local control and less severe side effects, compared to conventional fractionated radiotherapy. A description of this technology and a review of clinical applications to bone metastases are detailed herein.

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A Study on the Service Load State Behavior of Reinforced Concrete Plate Member

  • Bhang, Jee-Hwan;Kang, Won-Ho
    • KCI Concrete Journal
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    • v.12 no.2
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    • pp.55-72
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    • 2000
  • This paper proposes a mechanical model to describe the load-deformation responses of the reinforced concrete plate members under service load state. An Analytical method is introduced on the basis of the rotating crack model which considers equilibrium, compatibility conditions, load-strain relationship of cracked member, and constitutive law for materials. The tension stiffening effect in reinforced concrete structures is taken into account by the average tensile stress-strain relationship from the load-strain relationship for the cracked member and the constitutive law for material. The strain compatibility is used to find out the crack direction because the crack direction is an unknown variable in the equilibrium and compatibility conditions. The proposed theory is verified by the numerous experimental data such as the crack direction, moment-steel strain relationship, moment-crack width relationship. The present paper can provide some basis for the provision of the definition of serviceability for plate structures of which reinforcements are deviated from the principal stresses, because the present code defines the serviceability by the deflection, crack control, vibration and fatigue basically for the skeletal members. The proposed theory is applicable to predict the service load state behavior of a variety of reinforced concrete plate structures such as skew slab bridges, the deck of skew girder bridges.

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Fabrication of Microfibrous Structures with Rolled-Up Forms using a Bilayer Self-Assembly Process (이중층 자가조립 공정을 활용한 롤형태의 생체의료용 마이크로섬유 구조체 제작)

  • Kim, Yeong-Seo;Park, Suk-Hee
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.21 no.2
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    • pp.79-86
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    • 2022
  • Numerous fabrication techniques have been used to mimic cylindrical natural tissues, such as blood vessels, tendons, ligaments, and skeletal muscles. However, most processes have limitations in achieving the biomimetic properties of multilayered and porous architectures. In this study, to embrace both features, a novel self-assembly method was proposed using electrospun microfibrous sheets. A bilayer microfibrous structure, comprising two sheets with different internal stresses, was fabricated by electrospinning a polycaprolactone (PCL) sheet on a uniaxially stretched thermoplastic polyurethane (TPU) sheet. Then, by removing the stretching tension, the sheet was rolled into a hollow cylindrical structure with a specific internal diameter. The internal diameter could be quantitatively controlled by adjusting the thickness of the PCL sheet against that of the TPU sheet. Through this self-assembly method, biomimetic cylindrical structures with multilayer and porous features can be manufactured in a stable and controllable manner. Therefore, the resulting structures may be applied to various tissue engineering scaffolds, especially vascular and connective tissues.

Molecular analysis of alternative transcripts of equine AXL receptor tyrosine kinase gene

  • Park, Jeong-Woong;Song, Ki-Duk;Kim, Nam Young;Choi, Jae-Young;Hong, Seul A;Oh, Jin Hyeog;Kim, Si Won;Lee, Jeong Hyo;Park, Tae Sub;Kim, Jin-Kyoo;Kim, Jong Geun;Cho, Byung-Wook
    • Asian-Australasian Journal of Animal Sciences
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    • v.30 no.10
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    • pp.1471-1477
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    • 2017
  • Objective: Since athletic performance is a most importance trait in horses, most research focused on physiological and physical studies of horse athletic abilities. In contrast, the molecular analysis as well as the regulatory pathway studies remain insufficient for evaluation and prediction of horse athletic abilities. In our previous study, we identified AXL receptor tyrosine kinase (AXL) gene which was expressed as alternative spliced isoforms in skeletal muscle during exercise. In the present study, we validated two AXL alternative splicing transcripts (named as AXLa for long form and AXLb for short form) in equine skeletal muscle to gain insight(s) into the role of each alternative transcript during exercise. Methods: We validated two isoforms of AXL transcripts in horse tissues by reverse transcriptase polymerase chain reaction (RT-PCR), and then cloned the transcripts to confirm the alternative locus and its sequences. Additionally, we examined the expression patterns of AXLa and AXLb transcripts in horse tissues by quantitative RT-PCR (qRT-PCR). Results: Both of AXLa and AXLb transcripts were expressed in horse skeletal muscle and the expression levels were significantly increased after exercise. The sequencing analysis showed that there was an alternative splicing event at exon 11 between AXLa and AXLb transcripts. 3-dimentional (3D) prediction of the alternative protein structures revealed that the structural distance of the connective region between fibronectin type 3 (FN3) and immunoglobin (Ig) domain was different between two alternative isoforms. Conclusion: It is assumed that the expression patterns of AXLa and AXLb transcripts would be involved in regulation of exercise-induced stress in horse muscle possibly through an $NF-{\kappa}B$ signaling pathway. Further study is necessary to uncover biological function(s) and significance of the alternative splicing isoforms in race horse skeletal muscle.

Characterization of Lactate Dehydrogenase in Acanthogobius hasta (풀망둑(Acanthogobius hasta) 젖산탈수소효소의 특성)

  • Yum, Jung-Joo
    • Journal of Life Science
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    • v.18 no.2
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    • pp.264-272
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    • 2008
  • The lactate dehydrogenase (EC 1.1.1.27, LDH) isozymes in tissues from Acanthogobius hasta were characterized by biochemical, immunochemical and kinetic methods. The activities of LDH in skeletal muscle and eye tissues were 65.30 and 53.25 units, but LDH activities in heart and liver tissues were very low. LDH/CS (EC 4.1.3.7, citrate synthase) in skeletal muscle was the highest as 22.29. Specific activities of LDH in brain, eye and skeletal muscle were 56.45, 38.04 and 11.0 units/mg, respectively. The LDH isozymes in tissues were separated by polyacrylamide gel electrophoresis after immunoprecipitation with antiserum against $A_4,\;B_4$ eye-specific $C_4$ and liver-specific $C_4$. LDH $AC_4$ isozymes were detected predominantly in skeletal muscle, brain and eye tissues, and $B_4$ isozyme was detected in heart. Anodal eye-specific $C_4$ and cathodal liver-specific $C_4$ were coexpressed in A. hasta. The eye-specific $C_4$ isozyme showed higher activity in eye tissue, but liver-specific $C_4$ isozyme showed lower activity in liver. As a result, one part of molecular structures in $A_4\;and\;C_4,\;A_4\;and\;B_4$, and eye-specific $C_4$ and liver-specific $C_4$ were similar, but in $B_4\;and\;C_4$ were different with each other. Therefore the subunit A may be conservative in evolution, and the evolution of subunit B seems to be faster than that of subunit A. The LDH $A_4$ isozyme of skeletal muscle was purified in the fraction from elution with NAD+ containing buffer of affinity chromatography and eye-specific $C_4$ isozyme was eluted right after $A_4$, so the structure of eye-specific $C_4$ isozyme is similar to $A_4$. And LDH activity remained 35.22-43.47% as a result of the inhibition by pyruvate, the Michaelis-Menten constant values for pyruvate was 0.080-0.098 mM, and Vmax were 153.85 units, 35.09 units in skeletal muscle and eye, respectively. Also the $B_4$ isozyme was the thermo-stablest and $C_4$ was stabler than $A_4$ isozyme. The optimum pH of LDH was 6.5. The results mentioned above indicate that isozymes in tissues showed the properties between LDH $A_4\;and\;B_4$ isozyme as A. hasta was adapted to hypoxic conditions. Also LDH seems to function more effectively under anaerobic condition because LDH in skeletal muscle and eye tissues have high affinity for pyruvate.

A STUDY ON THE EFFECT OF RAPID MAXILLARY EXPENSION AND ITS RELAPSE (상악골 확장과 재발에 관한 연구)

  • Lee, Young-Il;Cha, Kyung-Suk
    • The korean journal of orthodontics
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    • v.21 no.2 s.34
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    • pp.447-455
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    • 1991
  • This research was carried out in order to study the effects of Rapid Maxillary Expansion on maxilla and it's surrounding skeletal structures. The sample for this study consists of 14 patients who were in retention period after rapid maxillary expansion. Following results were obtained after performing comparative analysis of cephalograms taken before and after rapid maxillary expansion. 1. In almost every cases, inferior displacement of palatal planes with concurrent changes in their inclination were observed. 2. Changes in the inclination of palatal plane can be categorized into inferiorty inclined group, superiorly inclined group and constant group in relation to the states before rapid masillary expansion. 3. Decrease in < Se-FMN/PMV and increase in < Se-FMN-A were evident in the superiorly inclined group and vice versa for the inferiorly inclined group.

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Osteological Study of the Mudhopper, Periopthalmus cantonensis (Perciformes, Gobiidae) from Korea (한국산 말뚝망둥어 Periopthalmus cantonensis(농어목:망둑어과)의 골학적 연구)

  • 이충렬
    • The Korean Journal of Zoology
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    • v.33 no.4
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    • pp.402-410
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    • 1990
  • The osteological characteristics of Mudhopper, P. cantonensis, was described and compared with its related species, Tridentiger obscurus, Synechogobius hasta and Odontogobius platycephala The skeletal structures of P. canionensis were distinctly different from those of other species in many respects: the form of the neurocranium, the pterygoid, the radial and the parhypural, the fused state between ribs and hypomerals. However, in respect of having five branchiostegals, two epurals and hypomerals, P. cantonensis were in common with T obscurus, S. hasia and O. platycephala.

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Bioactive Metabolites from Selected Sponges of Korean and Tropical Waters

  • Shin, Jong-Heon;Park, Jung-Rae;Seo, Young-Wan;Lee, Hyi-Seung;Cho, Ki-Woong
    • Proceedings of the PSK Conference
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    • 2001.04a
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    • pp.90-94
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    • 2001
  • Wondonins A and B, aromatic alkaloids of an unprecedented skeletal class have been isolated form and association of the sponges Poecillastra wondoensis and Jaspis sp. In addition, four novel bromotyrosine-derived metabolites, psammaplins $A_1$ and $A_2$, aplysinellins A and B, have been isolated from the tropical sponge Aplysinella rhax. The structures of these compounds have been determined on the basis of combined chemical and spectral analyses. The new compounds exhibited significant cytotoxicity and antiangiogenic activity as well as inhibitory activities against farnesyl protein transferase and leucine aminopeptidase. In addition to these compounds, several bioactive metabolites have been isolated from sponges of Korean and tropical waters.

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A New Record of Dendrophyllia compressa (Anthozoa: Hexacorallia: Scleractinia: Dendrophylliidae) from Korea

  • Choi, Eunae;Song, Jun-Im
    • Animal Systematics, Evolution and Diversity
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    • v.32 no.1
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    • pp.38-43
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    • 2016
  • Dendrophyllia compressa Ogawa and Takahashi, 1995 is newly reported from Korea. The specimen was collected off Seogwipo, Jeju-do, Korea in 1969. It is described herein based on the morphological characters of the skeletal structures. Dendrophyllia compressa is characterized by its small and bushy growth form with branches, vertical growth direction, small calicular diameter, compressed calice, Pourtalès Plan with vertical septal inner edges, flat and spongy columella, exserted septal upper margins, and epitheca. Dendrophyllia compressa has been synonymized with Cladopsammia eguchii . However, the former species differs from the latter species in its growth form, growth direction, colony size, corallite size, and corallite shape.