• Radiation Oncology Journal
• /
• v.13 no.2
• /
• pp.173-180
• /
• 1995

Purpose: Unresectable rectal cancer has a grave prognosis. regardless of the therapy used and median survival is less than 1 rear. Also, it is reported by many authors that $50-80\%$ of unresectable lesions were rendered resectable by radiation therapy and the median survival time for the completely resected patients were better than that of the unresected patients. So we analyzed retrospectively our data for the better treatment outcome in these patients. Materials and MEthods:From 1980 to 1992, 45 patients with initially unresectable tumors in the rectum were treated with radiation therapy with/without surgery in Department of Radiation Oncology, Yonsei Cancer Center 10 MV radiation and multiple field technique (box or AP/PA) were used. The total dose was 28-70 Gy and median dose was 48 Gy. We evaluated the lesion status at 45-50 Gy for operability. If the lesions appeared to be resectable, the Patients were operated on 4-6 weeks after radiation therapy. But if the lesions were still fixed, the radiation dose was increased to 60-65 Gy. Results: For all patients, the 2-year actuarial survival was $13.3\%$ and median survival was 9.5 months. Of 6 patients who had received less than 45 Gy, only $17\%$ of patients responded, but in the patients who had received more than 45 Gy, $60\%$ of response rate was achieved Six of the 24 patients$(25\%)$ underwent surgical resections following RT. For patients undergoing curative resection. the two-rear survival was $50\%,$ but that of the patients without resection was $9.5\%$ (p<0.01). Survival of patients with complete response following RT was $50\%$ at 2 years. Survival of patients with partial response, stable disease and progressive disease after RT was $13.4\%,\;15.4\%,\;0\%$ respectively (P<0.05). Conclision: Our data suffests that the efforts which can increase the response rate and aggressive surgical approach are needed to achieve the better local control and survival in unresectable rectal cancers.

• The Journal of the Korean dental association
• /
• v.47 no.11
• /
• pp.758-768
• /
• 2009

Purpose : Schulte introduced immediate implant cases in 1970s, since then many patients have been treated by immediate implants. The aim of this study was to evaluate the cumulative survival rate of immediate implant and to analyze various factors associated with survival of immediate implant in a 8-year period retrospectively. Materials and methods : From May, 2000 to October, 2007, 77 implants were placed in 63 patients immediately after tooth extraction at Department of Periodontology, Yonsei University Hospital. The implant survival rate was analyzed using a life-table analysis. After delivery of prosthesis, along 1 year of observation period, all implants were evaluated clinically and radiographically. Results : Among 77 implants, 59 were placed in maxilla and 18 in mandible. The most common site of the implantation was Mx anterior (65%). The overall survival rate was 94.8% over a mean follow-up period of $44.2{\pm}21$ months and the 8-year cumulative survival rate was 94.6%. Failure occurred in 4 implants, all of which were due to early failures. None of the following factors were significantly associated with the survival of immediate implants: advanced surgical technique including bone graft and guided bone regeneration, the types of implants, causes of tooth loss, and types of prosthesis. Conclusion : On the basis of 8-year life time analysis, immediate implant placement can be considered a safe and predictable treatment mordality.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 1998.04a
• /
• pp.245-253
• /
• 1998

Recently, the importance of multi-objective optimization techniques and stochastic search methods is increasing. The stochastic search methods have the concepts of the survival of the fittest and natural selection such as genetic algorithms(GA), simulated annealing(SA) and evolution strategies (ES). As many accidents of oil tankers cause marine pollution, oil tankers of double hull or mid deck structure are being built to minimize the marine pollution. For the improvement of oil tanker design technique, an efficient optimization technique is proposed in this study. Multi-objective optimization problem of weight and cost of double hull and mid deck tanker is formulated. Discrete design variables are used considering real manufacturing, and the concept of relative production cost is also introduced. The ES method is used as an optimization technique, and the ES algorithm was developed to generate a more efficient Pareto optimal set.

• Journal of Ship and Ocean Technology
• /
• v.9 no.1
• /
• pp.38-46
• /
• 2005

Survivability improvement method for naval ship design has been continually developed. In order to design naval ships considering survivability, it is demanded that designers should establish reasonable damage conditions by air explosion. Explosion may induce local damage as well as global collapse to the ship. Therefore possible damage conditions should be realistically estimated in the design stage. In this study the authors used ALE technique, one of the structure-fluid interaction techniques, to simulate air explosion and investigated survival capability of damaged naval ships. Lagrangian-Eulerian coupling algorithm, equation of the state for explosive and air, and simple calculation method for explosive loading were also reviewed. It is shown that air explosion analysis using ALE technique can evaluate structural damage after being attacked. This procedure can be applied to the real structural design quantitatively by calculating surviving time and probability.

• The Journal of the Korean dental association
• /
• v.48 no.8
• /
• pp.594-606
• /
• 2010

Lymph node status is the single most important prognostic factor in oral cancer because lymph node involvement decreases overall survival by 50%. Appropriate management of the regional lymphatics, therefore, plays a central role in the treatment of the oral cancer patients. The purposes of this article are to present the history of neck dissections, including current neck dissection classification, describe the technique of the most common neck dissection applicable to oral cavity cancers, and discuss some of the complications associated with neck dissection. Finally, a brief review of elective neck dissection and sentinel lymph node biopsy will be presented. It is necessary that dentists have to be interested in oral cancer and these interest will make it possible to prevent oral cancer, detect it earlier and also improve the prognosis, survival and the quality of life of survivors.

• BMB Reports
• /
• v.49 no.1
• /
• pp.26-36
• /
• 2016

Emerging trends for cardiac tissue engineering are focused on increasing the biocompatibility and tissue regeneration ability of artificial heart tissue by incorporating various cell sources and bioactive molecules. Although primary cardiomyocytes can be successfully implanted, clinical applications are restricted due to their low survival rates and poor proliferation. To develop successful cardiovascular tissue regeneration systems, new technologies must be introduced to improve myocardial regeneration. Electrospinning is a simple, versatile technique for fabricating nanofibers. Here, we discuss various biodegradable polymers (natural, synthetic, and combinatorial polymers) that can be used for fiber fabrication. We also describe a series of fiber modification methods that can increase cell survival, proliferation, and migration and provide supporting mechanical properties by mimicking micro-environment structures, such as the extracellular matrix (ECM). In addition, the applications and types of nanofiber-based scaffolds for myocardial regeneration are described. Finally, fusion research methods combined with stem cells and scaffolds to improve biocompatibility are discussed. [BMB Reports 2016; 49(1): 26-36]

• Radiation Oncology Journal
• /
• v.3 no.1
• /
• pp.9-12
• /
• 1985

To determine the radiosensitivity and dose-survival characteristics of jejunal crypt cells, experimental study was done using total 40 mice. Single irradiation of 1,000 rad to 1,600rad was delivered to whole bodies of mice, using a cesium 137 animal irradiator. The number of regenerating crypts per jejunal circumference was counted, by using a jejunal crypt cell assay technique, and dose response curve was measured. The average number of jejunal crypt Per circumference in control group was $140\pm10$. Mean lethal dose$(D_0)$ of moose jejunal crypt cell was 135rad.

• The Korean Journal of Pain
• /
• v.28 no.1
• /
• pp.22-31
• /
• 2015

Background: The celiac plexus and splanchnic nerves are targets for neurolytic blocks for pain relief from pain caused by upper gastrointestinal tumors. Therefore, we investigated the analgesic effect of a celiac plexus block versus a splanchnic nerve block and the effects of these blocks on the quality of life six months post-intervention for patients with upper GIT tumors. Methods: Seventy-nine patients with inoperable upper GIT tumors and with severe uncontrolled visceral pain were randomized into two groups. These were Group I, for whom a celiac plexus block was used with a bilateral needle retrocrural technique, and Group II, for whom a splanchnic nerve block with a bilateral needle technique was used. The visual analogue scale for pain (0 to 100), the quality of life via the QLQ-C30 questionnaire, and survival rates were assessed. Results: Pain scores were comparable in both groups in the first week after the block. Significantly more patients retained good analgesia with tramadol in the splanchnic group from 16 weeks onwards (P = 0.005, 0.001, 0.005, 0.001, 0.01). Social and cognitive scales improved significantly from the second week onwards in the splanchnic group. Survival of both groups was comparable. Conclusions: The results of this study demonstrate that the efficacy of the splanchnic nerve block technique appears to be clinically comparable to a celiac block. All statistically significant differences are of little clinical value.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.24 no.4
• /
• pp.381-388
• /
• 2008

Various techniques and diversely designed implants have been developed to overcome anatomic limitations of the maxillary posterior alveolar bone. The OSFE (osteotome sinus floor elevation) technique has been used for maxillary sinus augmentation. Also, $Endopore^{(R)}$ implant was designed to increase the surface area by its sintered porous surface. The purpose of this study was to evaluate the survival rate of $Endopore^{(R)}$ implants placed in the posterior maxilla in association with the elevation of the sinus membrane using OSFE technique, and examine the new bone formation in the sinus. One hundred fifteen $Endopore^{(R)}$ implants in 66 patients were placed in the posterior maxilla by OSFE technique. The implants were clinically and radiographically followed up for an average of 26.3 months. Most implants were stable and radiographs showed that the bone regenerated in contact with the implants. But, 5 implants in 4 patients were removed after the prosthetic restoration and the survival rate was 95.6% during the follow-up period. The height of new bone formed in the sinus was $3.26{\pm}1.04mm$.

• Radiation Oncology Journal
• /
• v.14 no.1
• /
• pp.25-31
• /
• 1996

Purpose : To evaluate the potential advantage for 'sandwich' technique radiotherapy compared to Postoperative radiotherapy in resectable rectal cancer. Materials and Methods : Between January 1989 and Mar 1994, 60 patients with resectable rectal cancer were treated at Inje University Seoul and Sanggye Paik Hospital. Fifty one patients were available for analysis: 20 patients were treated with sandwich technique radiotherapy and 31 patients were treated with Postoperative radiotherapy. In sandwich technique radiotherapy(RT), Patients were treated with preoperative RT 1500 cGy/5fx, followed by immediate curative resection. Patients staged as Astler-Coiler B2, C were considered for postoperative RT with 2500-4500 cGy. in postoperative RT total radiation dose of 4500-6120 cGy, 180 cGy daily at 4-Sweets was delivered. Patients were followed for median period of 25 months. Results : The overall 5-year survival rates for sandwich RT group and postoperative RT group were $60\%$ and $71\%$, respectively(p>0.05). The 5-rear disease free survival rates for each group were $63\%$. There was no difference in local failure rate between two groups($11\%$ versus $7\%$) Incidence of distant metastasis was $11\%$(2/20) in the sandwich technique RT group and $20\%$(6/31) in the postoperative RT group(p>0.05). The frequencies of acute and chronic complications were comparable in both groups. Conclusion : The sandwich technique radiotherapy group shows local recurrence and survival similar to those of Postoperative RT alone group but reduced distant metastasis compared to Postoperative RT group. But long term follow-up and large number of patients is needed to make an any firm conclusion regarding the value of this sandwich technique RT.