• Steel and Composite Structures
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• v.2 no.1
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• pp.21-34
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• 2002

A model of the process of local buckling in tubular steel structural elements is presented. It is assumed that this degrading phenomenon can be lumped at plastic hinges. The model is therefore based on the concept of plastic hinge combined with the methods of continuum damage mechanics. The state of this new kind of inelastic hinge is characterized by two internal variables: the plastic rotation and the damage. The model is valid if only one local buckling appears in the plastic hinge region; for instance, in the case of framed structures subjected to monotonic loadings. Based on this damage model, a new finite element that can describe the development of local buckling is proposed. The element is the assemblage of an elastic beamcolumn and two inelastic hinges at its ends. The stiffness matrix, that depends on the level of damage, the yielding function and the damage evolution law of the two hinges define the new finite element. In order to verify model and finite element, several small-scale frames were tested in laboratory under monotonic loading. A lateral load at the top of the frame was applied in a stroke-controlled mode until local buckling appears and develops in several locations of the frame and its ultimate capacity was reached. These tests were simulated with the new finite element and comparison between model and test is presented and discussed.

• Archives of Aesthetic Plastic Surgery
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• v.23 no.3
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• pp.143-145
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• 2017

Medical leech therapy is a treatment for the venous congestion of tissue flaps, grafts, and replants. We report a case of methicillin-resistant Staphylococcus aureus (MRSA) following leech application at a congested flap after mastectomy. A 45-year-old woman had an invasive ductal carcinoma. Modified radical mastectomy was performed. The chest wall defect was reconstructed with a local rotation flap. On postoperative day (POD) 1, congestion and color change were observed, and 10 medical leeches were applied to the congested area. On POD 4, another 10 medical leeches were applied. On POD 12, wound necrosis progressed and a pus-like discharge appeared. A wound swab culture revealed MRSA. Debridement was carried out on POD 15. From POD 16, vancomycin and piperacillin/tazobactam were injected for 18 days. The wound culture on POD 18 also revealed MRSA. A split-thickness skin graft was performed on POD 28. MRSA has not been clearly identified in the literature as a leech enteric bacterium. Although MRSA may have come from another source, the present case raises the possibility of MRSA infections following leech application at congested flaps. When medical leeches are applied at the congestion site of a flap, an aseptic cradle will be helpful. Vancomycin irrigation may be needed if infection occurs.

• Archives of Craniofacial Surgery
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• v.22 no.6
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• pp.341-344
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• 2021

Reconstruction of submental defects is a challenge that needs to be approached carefully, since many important anatomical structures are located in this small space. Both aesthetic and functional outcomes should be considered during reconstruction. In this report, we describe a case where a superficial branch of the transverse cervical artery (STCA) perforator propeller flap was applied for coverage of the submental area. An 85-year-old woman presented with a 3-cm ovoid mass on her submental area. We covered the large submental defect with a STCA rotational flap in a 180° propeller pattern. The flap survived well without any complications at 1 year of followup. A STCA propeller flap is a useful surgical option in reconstruction for defect coverage of the submental area.

• Archives of Plastic Surgery
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• v.49 no.1
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• pp.80-85
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• 2022

The instep flap and medialis pedis flap are both originate based on the medial plantar artery. The medialis pedis flap is based from the deep branch and the instep flap is based from the superficial branch. To increase the axial rotation, it is acceptable to ligate the lateral plantar artery. However, this can partially affect the blood supply of the plantar metatarsal arch. We restored the blood flow with a vein graft between the posterior tibial artery and the ligated stump. From 2012 to 2020, 12 cases of heel reconstruction, including seven instep flaps and five medialis pedis flaps, were performed with ligation of the lateral plantar artery. The stump of the lateral plantar artery was restored with a vein graft and between the posterior tibial artery and the ligated stump. Patients were followed for 18 months. Long-term results showed the vascular restoration of the lateral plantar artery remained patent demonstrated by doppler ultrasonography. Restoring blood flow to the lateral plantar artery maintains good blood supply to the toes. If the patient in the future develops a chronic degenerative disease, with microvascular complications, bypass surgery can still be performed because of the patency of both branches.

• Journal of Korean Society of Steel Construction
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• v.12 no.1 s.44
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• pp.65-73
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• 2000

The behavior of double angle connections is analyzed by 3D finite element method using ABAQUS(ver 5.8). Moment-rotation curves for the connections are generated, as well as stress distribution for angle and bolt. Double angle connections have various angle thickness, gage distance and number of bolt. Parameters, such as initial stiffness, plastic tiffness, reference load and curve shape parameter were obtained by regression method using Richard's formula. These parameter lead to predict nonlinear behavior of double angle connection. Design curves giving the parameters of the moment-rotation curves are generated. These parameters are primarily a function of the angle thickness, gage distance and the number of bolts in the connection. Using these parameters, connection moment and its ratio to the full plastic moment capacity Mp of the beam are calculated.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.36 no.1
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• pp.23-27
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• 2010

The purpose of this study was to evaluate the reliability of 6-axis model surgery simulator (6AMSS) for orthognathic surgery. A rectangular parallelepiped plastic block was assembled to model-mounting plate of 6AMSS. Left-right (X), anterior-posterior (Y), up-down (Z) translation and pitching (${\phi}X$), rolling (${\phi}Y$) and yawing (${\phi}Z$) rotation was planned and performed using 6AMSS. The actual translation and rotation were measured with dial gauge and precisional protractor, respectively. Comparison between the planned and actual movements of plastic block for each variable were made using paired t- test. Statistical analysis for X, Y, Z, ${\phi}X$, ${\phi}Y$ and ${\phi}Z$ movement have shown no significant differences between planned and actual movement (P > 0.05). This indicate that model surgery performed with the aid of the 6AMSS is accurate in 3D translation and rotation. The 6AMSS is practically useful for accurate fabrication of surgical splint for orthognathic surgery.

• Geomechanics and Engineering
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• v.37 no.4
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• pp.383-393
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• 2024

Monopile foundations of offshore wind turbines embedded in soft clay are subjected to the long-term cyclic lateral loads induced by winds, currents, and waves, the vibration of monopile leads to the accumulation of pore pressure and cyclic strains in the soil in its vicinity, which poses a threat to the safety operation of monopile. The researchers mainly focused on the hysteretic stress-strain relationship of soft clay and kinds of stiffness degradation models have been adopted, which may consume considerable computing resources and is not applicable for the long-term bearing performance analysis of monopile. In this study, a modified cyclic stiffness degradation model considering the effect of plastic strain and pore pressure change has been proposed and validated by comparing with the triaxial test results. Subsequently, the effects of cyclic load ratio, pile aspect ratio, number of load cycles, and length to embedded depth ratio on the accumulated rotation angle and pore pressure are presented. The results indicate the number of load cycles can significantly affect the accumulated rotation angle of monopile, whereas the accumulated pore pressure distribution along the pile merely changes with pile diameter, embedded length, and the number of load cycles, the stiffness of monopile can be significantly weakened by decreasing the embedded depth ratio L/H of monopile. The stiffness degradation of soil is more significant in the passive earth pressure zone, in which soil liquefaction is likely to occur. Furthermore, the suitability of the "accumulated rotation angle" and "accumulated pore pressure" design criteria for determining the required cyclic load ratio are discussed.

• Archives of Plastic Surgery
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• v.48 no.1
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• pp.107-113
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• 2021

Background Applicants to integrated plastic and reconstructive surgery (PRS) residency in the United States spend exorbitant amounts of time and money throughout the interview process. Outside of first-hand experience through a visiting rotation, applicants utilize various resources in learning about a program. Today's applicants are "Millennials," the demographic cohort raised during the information age and proficient with digital technology. The authors evaluated whether programs have a presence on social media, and whether applicants are following these accounts. Methods An online survey was sent to applicants to a single integrated plastic surgery program evaluating basic demographics, social media utilization, and sources of information accessed throughout the residency application process. A manual search of popular social media platforms (Instagram, Facebook, and Twitter) was performed in October 2019. Accounts affiliated with integrated PRS programs were identified and analyzed. Results Eighty-four of 222 applicants (37.8%) completed the survey. Ninety-six percent of applicants were within the Millennial demographic. Ninety-six percent of applicants had some form of social media presence, with Facebook (90%) and Instagram (87%) being the most popular platforms. Seventy-three percent of applicants reported following a PRS residency social media account. As of October 2019, 59 integrated residency programs (73%) have active Instagram accounts. Conclusions Applicants still rely on the program website when researching potential residencies, but social media is being rapidly adopted by programs. Program social media accounts should be used as a dynamic form of communication to better inform applicants of program strengths and weaknesses.

• Journal of the Earthquake Engineering Society of Korea
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• v.13 no.2
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• pp.59-68
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• 2009

For safe and economical design to provide strong earthquake resistance, the moment redistribution and plastic rotation of structures and their members needs to be evaluated. To achieve this, an earthquake design method was developed using secant stiffness analysis. To address the variation of member stiffness due to plastic rotation and moment redistribution, a structure was modeled with a beam-column element with non-rigid end connections (NREC element). Secant stiffness for the NREC element was determined based on the ductility demands of the structure and members. By performing a conventional linear analysis for the secant stiffness model, redistributed moments and plastic rotations of the members were computed. The proposed method was applied to a moment frame and two dual systems. The design results were verified using detailed nonlinear analyses.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.37
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• pp.36.1-36.7
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• 2015

Background: This study was performed to evaluate three-dimensional positional change of the condyle using three-dimensional computed tomography (3D-CT) following unilateral sagittal split ramus osteotomy (USSRO) in patients with mandibular prognathism. Methods: This study examined two patients exhibiting skeletal class III malocclusion with facial asymmetry who underwent USSRO for a mandibular setback. 3D-CT was performed before surgery, immediately after surgery, and 6 months postoperatively. After creating 3D-CT images by using the In-vivo $5^{TM}$ program, the axial plane, coronal plane, and sagittal plane were configured. Three-dimensional positional changes from each plane to the condyle, axial condylar head axis angle (AHA), axial condylar head position (AHP), frontal condylar head axis angle (FHA), frontal condylar head position (FHP), sagittal condylar head axis angle (SHA), and sagittal condylar head position (SHP) of the two patients were measured before surgery, immediately after surgery, and 6 months postoperatively. Results: In the first patient, medial rotation of the operated condyle in AHA and anterior rotation in SHA were observed. There were no significant changes after surgery in AHP, FHP, and SHP after surgery. In the second patient, medial rotation of the operated condyle in AHA and lateral rotation of the operated condyle in FHA were observed. There were no significant changes in AHP, FHP, and SHP postoperatively. This indicates that in USSRO, postoperative movement of the condylar head is insignificant; however, medial rotation of the condylar head is possible. Although three-dimensional changes were observed, these were not clinically significant. Conclusions: The results of this study suggest that although three-dimensional changes in condylar head position are observed in patients post SSRO, there are no significant changes that would clinically affect the patient.