• Tunnel and Underground Space
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• v.21 no.3
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• pp.235-243
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• 2011

In this study, a control blast method, which utilizes crack guide holes, is suggested to achieve smooth fracture plane and minimize blast damage zone (BDZ) in smooth blasting. In order to verify the effectiveness of crack guide holes on the fracture plane control in blasting, fracture process analyses which consider regular smooth blasting and guide hole smooth blasting had been conducted and the fracture planes resulting from the analyses had been compared. The analyses models considered the ignition of the blast holes using detonation cords and each guide hole placed between blast holes. From the results, the smooth blasting utilizing guide holes showed lower fracture plane roughness than regular smooth blasting method in the hole spacing range between 20 to 40cm.

• Tunnel and Underground Space
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• v.20 no.2
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• pp.125-130
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• 2010

Model blast experiments of mortar blocks were performed to investigate the effect of the guide hole on crack growth. The mortar block specimens have a blast charge hole and 8 guide holes. Two of circular guide hole, notched guide hole, diamond shaped guide hole and diamond shaped guide holder are installed around 110 mm, 165 mm and 220 mm apart from the charge hole for each specimen. From the blast experiments, it was revealed that all the guide hole used in this study were effective for controlling the crack growth at the fracture control.

• Archives of Craniofacial Surgery
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• v.9 no.2
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• pp.67-71
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• 2008

Purpose: Orbital floor fracture has open wound to maxillary sinus and if the patient has chronic maxillary sinusitis, it may be have more risk of infection, complications. The purpose of this comparative study is to be the effectiveness of prophylactic antibiotics in orbital floor fracture with chronic maxillary sinusitis. Methods: We studied 20 patients who diagnosed as orbital floor fracture with chronic maxillary sinusitis from march, 2005 to may, 2006. Among them 16 were male, 4 were female and age was ranged from 15 to 68, average was 42. A day before operation, Prophylactic antibiotics were used to 10 patients. Prophylactic antibiotics were not used to 10 patients. We defined control group as prophylactic antibiotics injection group a day before operation. After surgery, we confined use of same antibiotic for 7 days in both group. After 6 month from surgery, we compare the degree of enophthalmos from healthy side to legion side with hertel exopthalmometry(Inami, Japan) in control group and non-prophylactic antibiotics injection group. Results: In control group, comparison of discrepancy between enophthalmic eyeball and normal eyeball with Hertel exophthalmometer was 1.1 mm and non-prophylactic antibiotics injection group was 2.1 mm. In independent sample t-test, control group was showed statistically significant difference with non-prophylactic antibiotics injection group(p=0.007). Conclusions: In orbital floor fracture with chronic maxillary sinusitis, bacteria in maxillary sinus can increase post-operative complication by infecting infraorbital soft tissue, and it is thought to be antibiotic prophylaxis is play a role in decrease in degree of enophthalmos. We feel the need to further study of prophylactic antibiotics in orbital floor fracture with chronic maxillary sinusitis.

• Computers and Concrete
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• v.24 no.3
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• pp.207-222
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• 2019

This paper has presented an effective and accurate meso-scale finite element model for simulating the fracture process of concrete under compression-shear loading. In the proposed model, concrete is parted into four important phases: aggregates, cement matrix, interfacial transition zone (ITZ), and the initial defects. Aggregate particles were modelled as randomly distributed polygons with a varying size according to the sieve curve developed by Fuller and Thompson. With regard to initial defects, only voids are considered. Cohesive elements with zero thickness are inserted into the initial mesh of cement matrix and along the interface between aggregate and cement matrix to simulate the cracking process of concrete. The constitutive model provided by ABAQUS is modified based on Wang's experiment and used to describe the failure behaviour of cohesive elements. User defined programs for aggregate delivery, cohesive element insertion and modified facture constitutive model are developed based on Python language, and embedded into the commercial FEM package ABAQUS. The effectiveness and accuracy of the proposed model are firstly identified by comparing the numerical results with the experimental ones, and then it is used to investigate the effect of meso-structure on the macro behavior of concrete. The shear strength of concrete under different pressures is also involved in this study, which could provide a reference for the macroscopic simulation of concrete component under shear force.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.885-886
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• 2006

Significant advances in mechanical testing for hard materials are discussed in this paper. There are three specific areas that are covered. In the measurement of fracture toughness factors such as the control of slow crack growth to produce strating cracks, and evaluating reproducibility and repeatability of tests have been recently examined. The miniaturization of tests reduces the amount of material that is used in testing, improves the throughput of tests, and also improves cost effectiveness. New techniques such as stepwise testing and micro scratch testing have contributed to significant additions to the knowledge of the wear mechanisms that operate in these materials.

• The Journal of Korean Academic Society of Nursing Education
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• v.9 no.2
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• pp.234-243
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• 2003

The researcher has studied the types of accidents and injuries that most often occur to infants, toddlers and preschool children. Using this knowledge, a first aid program was developed for mothers. This researcher used a Quasi experimental study which consisted of a nonequivalent control group pretest - posttest design for injury first-aid knowle. The experimental group consisted of 32 mothers, and the control group consisted of 29. The education program consisted of the types of injury, the structure and function of skin, the methods of obsevation, first-aid awareness, and the standard of professional support in case of contusion, abrasion, laceration, fracture and burn. The education program was developed and based on 'the systemetic design of instruction' by Dick & Carey(1996) and utilized multimedia text book, pictures, examples, practice and discussions to increase understanding and effectiveness of learning. The data for this study was collected from September to early November, 2001. There were two fomative evauations, pretest and posttest with an intervention of education program. The analysis of the collected data was analyzed by descriptive analysis, ANOVA, t-test and paired t-test using the SPSS 10.0 program. The results as follows; 1. The experimental group, who was given an education program before the test, got higher marks on the injury first-aid knowledge than the control group. There was a significant difference in knowledge between experimental group and control group(t=6.578, p=.000). 2. The experimental group got higher marks on the action evaluation than the control group. There were significant differences in the certainity of action (t=8.546, p=.000) and the accuracy of action (t=7.654, p=.000) between experimental group and control group. This study examined how a first aid education program increased effectiveness in the knowledge and action of injury first-aid.

• Journal of Trauma and Injury
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• v.33 no.1
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• pp.18-22
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• 2020

Purpose: Damage control laparotomy has contributed to improved survival rates for severe abdominal injuries. A large part of severe abdominal injury occurs with a concomitant pelvic bone fracture. The safety and effectiveness of internal fixation of pelvic bone fracture(s) has not been established. The aim of the present study was to evaluate infection risk in the pelvic surgical site in patients who underwent emergent abdominal surgery. Methods: This single-center retrospective observational study was based on data collected from a prospectively maintained registry between January 2015 and June 2019. Patients who underwent laparotomy and pelvic internal fixation were included. Individuals <18 and ≥80 years of age, those with no microbiological investigations, and those who underwent one-stage abdominal surgery were excluded. Comprehensive statistical comparative analysis was not performed due to the small number of enrolled patients. Results: A total of six patients met the inclusion criteria, and the most common injury mechanism was anterior-posterior compression (67%). The average duration of open abdomen was 98 hours (range, 44-98), and the time interval between abdominal closure and pelvic surgery was 98 hours. One patient (16.7%) died due to multi-organ dysfunction syndrome. Micro-organisms were identified in the abdominal surgical site in five patients (83%), with no micro-organisms in pelvic surgical sites. There was no unplanned implant removal. Conclusions: Internal fixation of pelvic bone fracture(s) could be performed in the state of open abdomen, and the advantages of early fixation may countervail the risks for cross contamination.

• Archives of Plastic Surgery
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• v.34 no.6
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• pp.724-728
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• 2007

Purpose: The objective of this study is to prevent postoperative lower eyelid retraction and scleral show. There are several approaches for orbital rim reconstruction. But these techniques are sometimes difficult to perform, and have some merits and faults. Maybe most common unwanted and unpleasant result that we have experienced by subciliary incision preseptal approach is the lower eyelid retraction and the scleral show. Therefore, I want to find out the causes and the solutions for such complication. We must know the mechanics for those unpleasant result first of all. Methods: We conducted a comparison of postoperative photographs between retroseptal approach group and preseptal approach group, both with subciliary incision. In experimental retroseptal group, incision was applied at subciliary region. After elevating skin flap to preserve pretarsal muscle, not with muscle flap elevation, but direct oblique incision through the muscle, retroseptal dissection was applied to the ROOF and the septum. Fixating fracture line, periosteal and septal repair was followed by skin repair. The light compressive dressings and protection were kept in place for 7 days. The effectiveness of this operative method was made comparison with control group which the preseptal approach was applied to, by postoperative 2nd week and 2nd month. Results: Author's technique had been used in 20 patients and control group was composed of 50 patients over 19months period. There were better results in experimental group than in control group and all of experimental group had no complaint about the lower eyelid retraction and the scleral show. Conclusion: It must be known about the reason of the lower eyelid retraction and the scleral show induced by subciliary and preseptal approach. Mechanically it can be easily proved. And the solution maybe will be easier if we get more information about the mechanics. I recommend the retroseptal subciliary approach

• Journal of Korean Foot and Ankle Society
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• v.21 no.4
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• pp.151-155
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• 2017

Purpose: Reducing tenderness or pain on the ankle joint and improving the range of motion are thought to be possible using hyaluronate-based anti-adhesive agents. On the other hand, there are more aspects to be studied regarding the incidence of complications, such as resting pain, tenderness, and stiffness, after surgery. Therefore, the aim of this study was to prove the effectiveness of the agents after ankle fracture surgery. Materials and Methods: Patients, who underwent open reduction and internal fixation surgery due to ankle joint fractures from June 2015 to May 2016, were studied prospectively. Thirty patients of them received a $Guardix^{(R)}$ injection during their surgeries and were included in the injection group. The other 30 patients were included in the control group. Postoperatively, tenderness on the scar, a delay in wound healing, and the active range of motion were evaluated at 2, 6, and 12 weeks after surgery. Results: A significant difference in tenderness on the scar was observed 2 weeks after surgery. On the other hand, there was no significant difference at 6 and 12 weeks after the surgery. The agent-using group showed a 6.7% delay in wound healing and a 93.3% nondelaying. In the non-using group, the delay was 63.3%, while non-delay was 36.7% (p<0.001). The group that underwent $Guardix^{(R)}$ usage showed an effective result in the visual analogue scale, which was statistically significant (p<0.001). The result at 6 and 12 weeks after surgery showed a significant difference. Conclusion: Improvement was observed in the patients who underwent a $Guardix^{(R)}$ injection, regarding the range of motion, visual analog scale, and healing of the wound postoperatively.

• Archives of Plastic Surgery
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• v.43 no.1
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• pp.88-92
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• 2016

There are two general categories of lateral osteotomy techniques-the external perforating method and the internal continuous method. Regardless of which technique is used, procedural effectiveness is hampered by limited visualization in the surgical field. Considering this point, we devised a new technique that involves using a wide subperiosteal dissection and internal perforation under direct visualization. Using an intranasal approach, whereby the visibility of the intended fracture line was maintained, enabled a greater degree of control, and in turn, results that were more precise, and thus predictable and reproducible. Traditionally, it has been taken as dogma that the periosteum must be preserved, considering the potential for dead space and bony instability; however, under sufficient visualization of the surgical field with an internal perforating method, complete osteotomy with fully preserved intranasal mucosa could be conducted exactly as intended. This intact mucosal lining compensates for the elevated periosteum. Compressive dressing and drainage through a Silastic angio-needle catheter enabled the elimination of dead space. Therefore, precise, reproducible, and predictable osteotomy minimizing the potential for associated complications such as ecchymosis, that is, bruising owing to hemorrhage, could be performed. In this article, we introduce a novel technique for lateral osteotomy with improved visualization.