• Journal of Korean Society of Steel Construction
• /
• v.29 no.1
• /
• pp.81-88
• /
• 2017

Residual stress is defined as stress that already exists on a structural member from the effects of welding and plastic deformation before the application of loading. Due to such residual stress, welded H-section compression members under centroidal compression load can undergo buckling and failure for strength values smaller than the predicted buckling load and specified compressive strength. Therefore, this study was carried out to evaluate the effect of residual stress from welding on the determination of the buckling load and specified compressive strength of the H-section compression member according to the column length variation. A three-dimensional nonlinear finite element analysis was performed for the H-section compression member where the welded joint was fillet welded by applying heat inputs of 3.1kJ/mm and 3.6kJ/mm using the SAW welding method.

• Radiation Oncology Journal
• /
• v.33 no.1
• /
• pp.12-20
• /
• 2015

Purpose: To evaluate treatment outcomes and determine prognostic factors in patients with esophageal cancer treated with esophagectomy after neoadjuvant chemoradiotherapy (NCRT) Materials and Methods: We retrospectively evaluated 39 patients with esophageal cancer who underwent concurrent chemoradiotherapy followed by esophagectomy between 2002 and 2012. Initial clinical stages of patients were stage IB in 1 patient (2.6%), stage II in 5 patients (12.9%), and stage III in 33 patients (84.6%). Results: The median age of all the patients was 62 years, and the median follow-up period was 17 months. The 3-year overall survival (OS) rate was 33.6% in all the patients. The 3-year locoregional recurrence-free survival (LRFS) rate was 33.7%. In multivariate analysis with covariates of age, the Eastern Cooperative Oncology Group performance status, hypertension, diabetes mellitus, tumor length, clinical response, clinical stage, pathological response, pathological stage, lymphovascular invasion, surgical type, and radiotherapy to surgery interval, only pathological stage was an independent significant prognostic factor affecting both OS and LRFS. The complications in postoperative day 90 were pneumonia in 9 patients, anastomotic site leakage in 3 patients, and anastomotic site stricture in 2 patients. Postoperative 30-day mortality rate was 10.3% (4/39); the cause of death among these 4 patients was respiratory failure in 3 patients and myocardial infarction in one patient. Conclusion: Only pathological stage was an independent prognostic factor for both OS and LRFS in patients with esophageal cancer treated with esophagectomy after NCRT. We could confirm the significant role of NCRT in downstaging the initial tumor bulk and thus resulting in better survival of patients who gained earlier pathological stage after NCRT.

• The Journal of Advanced Prosthodontics
• /
• v.3 no.4
• /
• pp.229-235
• /
• 2011

PURPOSE. The aim of this retrospective study was to evaluate cumulative survival rate (CSR) of Implantium implants followed for 5 years and association between risk factors and the CSR. MATERIALS AND METHODS. A total of two hundred forty-nine Implantium Implants System (Dentium, Seoul, Korea) placed in ninety-five patients from 2004 to 2009 were investigated with several identified risk factors (sex, systemic disease, smoking, alchohol, reason of tooth loss, length, arch (maxilla or mandible), replace tooth type (incisor, canine, premolar or molar) Kennedy classification, prosthodontic type, prosthodontic design, opposite dentition, abutment type, occlusal material, occlusal unit, splint to tooth, cantilever, other surgery). Clinical examination (mobility, percussion, screw loosening, discomfort, etc.) and radiographic examination data were collected from patient records including all problems during follow-up period according to protocols described earlier. Life table analysis was undertaken to examine the CSR. Cox regression method was conducted to assess the association between potential risk factors and overall CSR. RESULTS. Five of 249 implants were failed. Four of these were lost before loading. The 5-year implant cumulative survival rate was 97.37%. Cox regression analysis demonstrated a significant predictive association between overall CSR and systemic disease, smoking, reason of tooth loss, arch, Kennedy classification and prosthodontic design (P<.05). The screw related complication was rare. Two abutment screw fractures were found. Another complications of prosthetic components were porcelain fracture, resin facing fracture and denture fracture (n=19). CONCLUSION. The 5-year CSR of Implantium implants was 97.37 %. Implant survival may be dependent upon systemic disease, smoking reason of tooth loss, arch, Kennedy classification and prosthodontic design (P<.05). The presence of systemic diseases and combination of other surgical procedures may be associated with increased implant failure.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.33 no.4
• /
• pp.352-358
• /
• 2011

Purpose: This study evaluated the prognosis and survival rate of SLA (Sandblasted, Large-grit and Acid-etched) implants and it also evaluated the prosthodontic complications and the associated factors. Methods: Twenty seven patients (14 men and 13 women, mean age: 54.9) who visited Chosun University Hospital Implant Center with the chief desire for placement of an implant in an edentulous area from March, 2008 to December 2008 and who received placement of a SLA implant ($Implantium^{(R)}$, Dentium Co., Korea) were selected for this study. Results: The average follow-up period was 15 months and the study was based on the treatment records, radiographs and clinical examinations. A total of 69 implant cases were retrospectively assessed for the width and length of the implant, the primary and secondary stability, the combined surgery, the employed bone graft material and barrier membrane, the status of the opposing tooth, implant failure and the prosthetic complications. During the follow-up period (average: 15 months), the accumulative survival rate of the 69 implants in 27 patients was 100%. Complications such as infection, sinusitis and fixture exposure after surgery were seen for 5 implants in 4 patients. Complications such as screw loosening, contact loosening and peri-implant gingivitis after prosthodontic treatment occurred in 7 cases (10.14%). Conclusion: This study reports placement of SLA implants may cause various complications, yet the final accumulative survival rate was 100%. The SLA implant ($Implantium^{(R)}$) has an excellent clinical survival rate and outcome.

• Journal of the Korea Concrete Institute
• /
• v.17 no.3 s.87
• /
• pp.375-384
• /
• 2005

The effects of bar deformation properties on bond of steel reinforcing bars to concrete are experimentally studied to predict the bond strength. Based on the previous research about high relative rib area, bond strength between reinforcing bars and concrete can be improved by the control of rib height and spacing. But, the equations in Korean code provisions to estimate development and splice length do not include these specifications of reinforcing bars. So the purpose of this paper is to determine the effect of relative rib area to the bond strength. This paper describes 2 kinds of experimental researches. Thirty beam-end specimens were tested to investigate the effects of bar size and relative rib areas ranging from 0.112 to 0.162. And, twelve lap-splice beam specimens were tested to the same variables. Each test results are normalized and compared with the proposed equations of ACI 408 committee. The results show that bond strength is increased as bar size and the relative rib area(Rr) increase. The distribution of flexural cracks and failure aspect do not appear to be affected by $R_r$.

• Journal of the Korea Concrete Institute
• /
• v.19 no.4
• /
• pp.467-474
• /
• 2007

In this paper, a total of 13 beams with bonding, anchorage system, amount of prestressing and span length as variables of experiment were tested in flexural test and analyzed in finite element analysis; one control beam, two simplified FRP-boned beams, four prestressed FRP-unbonded beams and four prestressed FRP-bonded beams. Also, a nonlinear finite element analysis of beams in the flexural test is performed by DIANA program considered material nonlinear of concrete, reinforcement and the interfacial bond-slip model between concrete and CFRP plates. The failure mode of prestressed CFRP plated-beams is not debonding but FRP rupture. RC members strengthened with external bonded prestressed CFRP plates occurred 1st and 2nd debonding of the composite material. After the debonding of CFRP plates occurs in bonded system, behavior of bonded CFRP-plated beams change into that of unbonded CFRP-plated beams due to fix of the anchorage system. Also, It was compared flexural test results and analytical results of RC members strengthened with CFRF plates. The ductility of beams strengthened by CFRP plates with the anchorage system is considered high with the ductility index of above 3. Analysis results showed a good agreement with experiment results in the debonding load, yield load and ultimate load.

• Journal of Gastric Cancer
• /
• v.7 no.4
• /
• pp.200-205
• /
• 2007

Purpose: The aim of this study was to analyze the post operative outcome of reconstruction with using the stomach after performing total pharyngolaryngoesophagectomy in patients with hypopharyngeal cancer or cervical esophageal cancer. Materials and Methods: We conducted a retrospective chart review of 23 patients who underwent gastric pull up for esophageal substitution at the Department of Surgery, Yonsei University College of Medicine, between January 1991 and December 2006. All the patients had transhiatal esophagectomy performed without thoracotomy. Results: There were seventeen males and six females with a median age of 58.1 years (range: 40-70 years). 19 cases were hypopharyngeal cancer, 13 cases had cancer in the pyriform sinus, 15 cases had cancer in the postcricoid area and one case had cancer in the glottic area. The rest were cervical esophageal cancers. The pathologic result was squamous cell carcinoma in all cases. The median total follow-up period was 33 months (range: 1-62 months) and there were two (8.6%) postoperative deaths: one was due to carotid rupture and the other was due to hepatic failure with liver metastasis. The complications were leakage in 1 patient (4.4%), pneumothorax in 1 patient (4.4%) and pneumonia in 1 patient (4.4%). Conclusion: The use of stomach for esophageal reconstruction has many benefits for treating hypopharyngeal cancer or cervical esophageal cancer, So, we made sure there was a sufficient length for the anastomosis after pharyngolaryngoesophagectomy and a rich blood supply from the stomach. There was a low incidence of the leakage at the anastomotic site, along with a low incidence of stenosis and bleeding.

• Journal of the Korean GEO-environmental Society
• /
• v.4 no.3
• /
• pp.27-40
• /
• 2003

In the present study, a newly modified soil nailing technology named as the PSN(Pretension Soil Nailing) system is proposed. Effects of various factors related to the design of the pretension soil nailing system, such as the length of a sheathing pipe and the fixed cone, are examined throughout a series of the displacement-controlled field pull-out tests. 9 displacement-controlled field pull-out tests are performed in the present study and the pretension forces are also evaluated based on the measurements. In addition, both short-term and long-term characteristics of pull-out deformations of the newly proposed PSN system are analyzed and compared with those of the general soil nailing system by carrying out the stress-controlled field pull-out tests. A numerical approach is further made to determine a postulated failure surface as well as a minimum safety factors of the proposed PSN system using the shear strength reduction technique and the $FLAC^{2D}$ program. Global minimum safety factors and local safety factors at various excavation stages computed in case of the PSN system are analyzed throughout comparisons with the results expected in case of the general soil nailing system. An efficiency of the PSN system is also dealt with by analyzing the wall-facing deformations and the adjacent ground surface settlements.

• Archives of Reconstructive Microsurgery
• /
• v.6 no.1
• /
• pp.96-102
• /
• 1997

The gracilis that is frequently used as a donor of free muscle trasfer is appropriate in the muscular shape and vascular position. This muscle is belonged to the second type of muscle group by the classification of the pattern of muscular nutrient vessel. The adductor branch or first perforating branch of deep femoral artery which supplies the proximal 1/3 of this muscle is a dominant one and this is used for the microscopic anastomosis of muscle or musculocutaneous flap. The minor vascular pedicles which enter the distal 1/3 of this of this muscle are branches of the superficial femoral artery and it is 0.5mm in diameter, 2cm in length with two venae comitantes. These minor pedicles supplies distal half of the gracilis muscle. This island musculocutaneous flap using distal vascular pedicle can be used to cover the defect of soft tissue around the distal femoral supra-condylar area, knee joint and proximal tibial condyle area which cause limitation of motion of knee joint, or in the cases that usual skin graft is impossible. The important operative procedure is as follows; The dissection is carried proximally and distally and the entire gracilis muscle including proximal and distal pedicle is completely dissected. After temporary blocking of the proximal vascular pedicle, the adequate muscle perfusion by the distal pedicle is identified and it is rotated to the recipient site around knee joint. The advantages of this procedure are simple, no need of microscopic vascular anastomoses and no significant functional loss of donor site. Especially in the cases of poor condition of the recipient vessel, this procedure can be used effectively. From 1991 to 1996, we performed 4 cases; complete survival of flap in 3 cases and partial survival of flap with partial necrosis in 1 case. This procedure is though to be useful in the small sized soft tissue defect of distal femoral supra-condylar area, knee joint and proximal tibial condylar area, especially in the defect of anterior aspect which expected to cause limitation of motion of knee joint due to scar contracture. But the problems of this procedure are the diameter of distal vascular pedicle is small and the location of distal vascular pedicle is not constant. To reduce the failure rate, identify the muscular perfusion of distal vascular pedicle after blocking the proximal pedicle, or strategic delay will be helpful.

• Asian Pacific Journal of Cancer Prevention
• /
• v.16 no.17
• /
• pp.8009-8013
• /
• 2015

Background: Orthotopic organ transplantation, a treatment option for irreversible organ dysfunction according to organ failure, severe damaged organ or malignancy in situ, was usually accompanied with massive blood loss thus transfusion was required. We aimed to evaluate the adverse impact of blood transfusion on solid organ transplantation. Materials and Methods: From January, 2009 to December, 2014, patients who received orthotopic organ transplantation at Far Eastern Memorial Hospital medical center were enrolled. Clinical data regarding anemia status and red blood cell (RBC) transfusion before, during and after operation, as well as patient outcomes were collected for further univariate analysis. Results: A total of 105 patients who underwent orthotopic transplantation, including liver, kidney and small intestine were registered. The mean hemoglobin (Hb) level upon admission and before operation were $11.6{\pm}1.8g/dL$ and $11.7{\pm}1.7g/dL$, respectively; and the nadir Hb level post operation and the final Hb level before discharge were $8.3{\pm}1.6g/dL$ and $10.2{\pm}1.6g/dL$, respectively. The median units (interquartile range) of RBC transfusion in pre-operative, peri-operative and post-operative periods were 0 (0-0), 2 (0-12), and 2 (0-6) units, respectively. Furthermore, the median (interquartile range) length of hospital stay (LHS) from admission to discharge and from operation to discharge were 28 (17-44) and 24 (16-37) days, respectively. Both peri-operative and post-operative RBC transfusion were associated with longer LHS from admission to discharge and from operation to discharge. Furthermore, it increased the risk of post-operative septicemia. While peri-operative RBC transfusion elevated the risk of acute graft rejection in patients who received orthotopic transplantation. Conclusions: Worse outcome could be anticipated in those who had received massive RBC transfusion in transplantation operation. Hence, peri-operative RBC transfusion should be avoided as much as possible.