• Earthquakes and Structures
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• v.26 no.3
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• pp.203-218
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• 2024

Beam-column joints in the frame structure are at high risk of brittle shear failure which would lead to significant residual deformation and even the collapse of the structure during an earthquake. In order to improve the damage issue and enhance the recoverability of the beam-column joints, a sector lead rubber damper (SLRD) has been developed. The SLRD can increase the bearing capacity and energy dissipation capacity, and also demonstrating recoverability of seismic performance following cyclic loading. In this paper, the hysteretic behavior of SLRD was experimentally investigated in terms of the regular hysteretic behavior, large deformation behavior and fatigue behavior. Furthermore, a parametric analysis was performed to study the influence of the primary design parameters on the hysteretic behavior of SLRD. The results show that SLRD resist the exerted loading through the shear capacity of both rubber parts coupled with the lead cores in the pre-yielding stage of lead cores. In the post-yielding phase, it is only the rubber parts of the SLRD that provide the shear capacity while the lead cores primarily dissipate the energy through shear deformation. The SLRD possesses a robust capacity for large deformation and can sustain hysteretic behavior when subjected to a loading rotation angle of 1/7 (equivalent to 200% shear strain of the rubber component). Furthermore, it demonstrates excellent fatigue resistance, with a degradation of critical behavior indices by no more than 15% in comparison to initial values even after 30 cycles. As for the designing practice of SLRD, it is recommended to adopt the double lead core scheme, along with a rubber material having the lowest possible shear modulus while meeting the desired bearing capacity and a thickness ratio of 0.4 to 0.5 for the thin steel plate.

• The Korean journal of internal medicine
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• v.39 no.4
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• pp.680-690
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• 2024

Background: To evaluate the effectiveness of Korean Red Ginseng (KRG) in managing fatigue in Korean patients with rheumatic diseases Methods: Patients were randomly assigned to KRG (2 g/day, n = 60) or placebo (n = 60) groups for 12 weeks of blind phase and then open-label KRG from weeks 12 to 24 (placebo-KRG, continuous-KRG). The primary outcome was the improvement rate in fatigue, defined by an increase in Functional Assessment of Chronic Illness Therapy (FACIT)-Fatigue scores at 12 weeks. Secondary outcomes included changes in FACIT-Fatigue and fatigue visual analog scale (VAS) between 0 and 12 weeks and those changes in both indices at 24 weeks. Results: The study enrolled 120 patients (Sjogren syndrome [n = 53], rheumatoid arthritis [n = 43], or both diseases [n = 24]). The mean age was 50.9 ± 11.6 years, with 97.5% being female. Baseline characteristics were similar between the two groups. The improvement rate in FACIT-Fatigue after 12 weeks was higher in the KRG group than in the placebo group, but the difference was statistically insignificant (38.3% vs. 26.7%, p = 0.242). Improvement in fatigue was observed in both groups by increases in FACIT-F (4.6 vs. 4.0) and reductions in fatigue VAS (-16.0 vs. -12.2) scores at 12 weeks. The most frequently reported adverse events during KRG use were pruritus and urticarial, with no significant difference between the two groups. Conclusions: Both KRG and placebo groups showed significant reductions in fatigue. KRG treatment for 24 weeks did not reduce fatigue symptoms more than the placebo in patients with rheumatic diseases.

• Clinical Endoscopy
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• v.57 no.5
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• pp.595-603
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• 2024

Background/Aims: Coaxial placement of double pigtail plastic stents (DPPS) through lumen-apposing metal stents (LAMSs) is commonly performed to reduce the risk of LAMS obstruction, bleeding, and stent migration when used for the drainage of pancreatic fluid collections (PFCs). A systematic review and meta-analysis were performed to compare the outcomes of LAMS alone and LAMS with coaxial DPPS placement in the management of PFCs. Methods: A systematic review was conducted to identify studies comparing LAMS and LAMS/DPPS for PFC drainage. Primary outcomes included the rate of clinical success, overall adverse events (AEs), bleeding, infection, occlusion, and stent migration. The pooled effect size was summarized using a random-effects model and compared between LAMS and LAMS/DPPS by calculating odds ratios (ORs). Results: Nine studies involving 709 patients were identified (338 on LAMS and 371 on LAMS/DPPS). LAMS/DPPS was associated with a reduced risk of stent obstruction (OR, 0.59; p=0.004) and infection (OR, 0.55; p=0.001). No significant differences were observed in clinical success (OR, 0.96; p=0.440), overall AEs (OR, 0.57; p=0.060), bleeding (OR, 0.61; p=0.120), or stent migration (OR, 1.03; p=0.480). Conclusions: Coaxial DPPS for LAMS drainage of PFCs is associated with a reduced risk of stent occlusion and infection; however, no difference was observed in the overall AE rates or bleeding.

• Korean Journal of Mathematics
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• v.32 no.3
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• pp.381-406
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• 2024

The logistic growth model was developed with a single population in mind. We now analyze the growth of two interdependent populations, moving beyond the one-dimensional model. Interdependence between two species of animals can arise when one (the "prey") acts as a food supply for the other (the "predator"). Predator-prey models are the name given to models of this type. While social scientists are mostly concerned in human communities (where dependency hopefully takes various forms), predator-prey models are interesting for a variety of reasons. Some variations of this model produce limit cycles, an interesting sort of equilibrium that can be found in dynamical systems with two (or more) dimensions. In terms of substance, predator-prey models have a number of beneficial social science applications when the state variables are reinterpreted. This paper provides a quick overview of numerous predator-prey models with various types of behaviours that can be applied to ecological systems, based on a survey of various types of research publications published in the last ten years. The primary source for learning about predator-prey models used in ecological systems is historical research undertaken in various circumstances by various researchers. The review aids in the search for literature that investigates the impact of various parameters on ecological systems. There are also comparisons with traditional models, and the results are double-checked. It can be seen that several older predator-prey models, such as the Beddington-DeAngelis predator-prey model, the stage-structured predator-prey model, and the Lotka-Volterra predator-prey model, are stable and popular among academics. For each of these scenarios, the results are thoroughly checked.

• Radiation Oncology Journal
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• v.26 no.1
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• pp.17-23
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• 2008

Purpose: The best treatment for advanced esophageal cancer is chemoradiotherapy followed by surgery. In spite of the advance of multimodality therapy, most patients with esophageal cancer are treated with radiation therapy alone. This study reports the outcome of the use of conventional external beam radiotherapy alone for the treatment of esophageal cancer. Materials and Methods: Between January 1998 and December 2005, 30 patients with squamous cell carcinoma of the esophagus were treated with external beam radiotherapy using a total dose exceeding 40 Gy. Radiotherapy was delivered with a total dose of 44-60 Gy(median dose, 57.2 Gy) over $36{\sim}115$ days(median time, 45 days). Thirteen patients(43.3%) had a history of disorders such as diabetes, hypertension, tuberculosis, lye stricture, asthma, cerebral infarct, and cancers. Four patients metachronously had double primary cancers. The most common location of a tumor was the mid-thoracic portion of the esophagus(56.7%). Tumor lengths ranged from 2 cm to 11 cm, with a median length of 6 cm. For AJCC staging, stage III was the most common (63.3%). Five patients had metastases at diagnosis. Results: The median overall survival was 8.3 months. The survival rates at 1-year and 2-years were 33.3% and 18.7%, respectively. The complete response rate $1{\sim}3$ months after radiotherapy was 20%(6/30) and the partial response rate was 70%(21/30). Sixteen patients(53.3%) had an improved symptom of dysphagia. Significant prognostic factors were age, tumor length, stage, degree of dysphagia at the time of diagnosis and tumor response. Cox regression analysis revealed the aim of treatment, clinical tumor response and tumor length as independent prognostic factors for overall survival. Twenty-eight patients had local failure and another four patients had metastases. Three patients were detected with double primary cancers in this analysis. A complication of esophageal stricture was observed in three patients(10%), and radiation pneumonitis occurred in two patients(6.7%). Conclusion: The prognosis of esophageal cancer remains poor, in spite of advances in radiotherapy techniques. Radiotherapy is one of the main treatment modalities for the relief of dysphagia and treatment related complications are minimal. It is expected that the addition of chemotherapy or another systemic modality to radiotherapy will improve tumor control and increase the survival rate in advanced esophageal cancer.

• Investigative Magnetic Resonance Imaging
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• v.9 no.2
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• pp.101-108
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• 2005

Purpose : Early detection of small brain metastases is important. The purpose of this study was to compare the detectability of brain metastases according to the size between 1.5 T and 3.0 T MRI. Materials and Methods : We reviewed 162 patients with primary lung cancer who were examined for TNM staging. After administration of double dose of Gd-DTPA, MR imaging was performed with SPGR by 3.0 T MRI and then with T1 SE sequence by 1.5 T MRI. In each patient, three readers performed qualitative assessment. Sensitivity, positive predictive value, and diagnostic accuracy were calculated in 3.0 T and 1.5 T MRI according to size. Using the signal intensity (SI) measurements between the metastatic nodules and adjacent tissue, nodule-to-adjacent tissue SI ratio was calculated. Results : Thirty-one of 162 patients had apparent metastatic nodules in the brain at either 1.5 T or 3.0 T MR imaging. 143 nodules were detected in 3.0 T MRI, whereas 137 nodules were detected at 1.5 T MRI. Six nodules, only detected in 3.0 T MRI, were smaller than 3.0 mm in dimension. Sensitivity, positive predictive value, and diagnostic accuracy in 3.0 T MRI were 100 %, 100 %, and 100 % respectively, and in 1.5 T MRI were 95.8%, 88.3%, and 85.1% respectively. SI ratio was significantly higher in the 3.0 T MRI than 1.5 T MRI (p=0.025). Conclusion : True positive rate of 3.0 T MRI with Gd-DTPA was superior to 1.5 T MRI with Gd-DTPA in detection of metastatic nodules smaller than 3.0 mm.

• Journal of Technologic Dentistry
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• v.25 no.1
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• pp.203-218
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• 2003

The 3 year graduate school course of the dental technician, which has been enforced since 1994 till the present date, differs from the currently existing 2 year graduate course because of an 8 weeks clinical field training course being newly executed and an imposed curriculum about manufacturing specialized prosthetics like all-ceramic, double prosthetic technology, attachment, and implant. Even though nearly 10 years have passed, the education program of the 18 colleges have still not been standardized and the subjects differing a little, while some are still not following the 3 years graduate course. The goal of this research is to emphasize the qualities of the 3 years graduate program and enable the dental technician to handle clinical models in the dental technical clinic right after graduation by adding clinical field training in the dental technician education program of the 18 colleges. Also in accordance to a national and international increase in esthetical prosthetics, credits, weekly study hours, education practice time of specialized prosthetic dental technology can be analyzed as follows. 1. In the year 2003, currently colleges start clinical practice education starting from the 1st semester of the 2nd year junior year, to the 2nd semester of 3rd year the varying in time with adequate class time, and credits. The average credit is 9.56, and weekly average class time is 18.00 hours. later clinical trainee education will be adjusted to the 3 year graduate school course to 10 credits and 20 hours and the adequate education period should be the 2nd semester of 3rd grade when most basic clinical education has been covered. 2. Currently in the year 2003, all-ceramic education has an average credit of 8.01 in 17 colleges with an exception of Ma-san college. The weekly average theoretical education is 4.94 hours, weekly clinical education of 7.88 hours and currently in 14 colleges porcelain technical class usually starts in the 1st semester of the 2nd year. All-ceramic education is thought to have adequate credits, timing, and weekly study hours. 3. Currently in 2003 implant education is enforced in 11 colleges including Bu-san Catholic university and the education period is usually in the 3rd year. Out of the 11 colleges, only Bu-san Catholic univ., Ma-san and Shinheung college have practice training classes. We knew that Shingu, Dongu, Mokpo science colleges have practice training as a curriculum, namely specific prosthetics laboratory. Out of the 9 colleges enforcing implant education the average credits taken are 2.56, and the average hours of weekly theory education is 2.14, but with the exception of Shinheung college which has an implant practice training course theory and practice classes are not divided. Therefore implant education is thought to start in the 3rd year as a 3 credit course with 3 hours of theory and practice each. 4. Currently in 2003, theoretical attachment education is given in 15 colleges and including practical training it is given in 10 colleges. The education starts 1st semester of the 2nd year till the 2nd semester of the 3rd year. The average credit of attachment theory education in the 15 colleges was 3.64, the average weekly theoretical education was 2.64, and the average weekly practice training out of the schools teaching it was 3.20. Later attachment education is thought to start the 1st semester of the 3rd year as a 3 credit course with 2 hours of theory class and 3 hours of practice training. 5. Double prosthetic technology is currently carried out in Dae-jon Health Science college(2nd year 2nd semester, 2 credits, theory 2hours), Gimcheon college (1 credit, 2 hours of practical training), Bu-san Catholic university (4th year 2nd semester, 4 hours of theory. practice). When the 3 year course is enforced, education will start 1st semester of the 3rd year with 2hours of theory and practice each. 6. The newly installed programs of the 3 year education is clinical field training, and specialized prosthetic manufacturing practice like all-ceramic, double prosthetic technology, attachment, and implant. If such education is to be effectively managed, a primary precursor as systemic basic clinical education is thought to be important. 7. Nationally in the 18 colleges of dental technology the currently executed curriculum course had varying subjects, class time according to the subject, and credits by each college. The curriculum difference between the colleges must be settled.

• Radiation Oncology Journal
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• v.18 no.4
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• pp.233-243
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• 2000

Purpose : First of all, this study was performed to assess the result of curative radiotherapy and to evaluate different possible prognostic factors for squamous cell carcinoma of the supraglottic larynx treated at the Pusan National University Hospital. The second goal of this study was by comparing our data with those of other study groups, to determine the better treatment policy of supraglottic cancer in future. Methods and Material : Thirty-two patients with squamous cell carcinoma of the supraglottic larynx were treated with radiotherapy at Pusan National University Hospital, from August 1985 to December 1996. Minimum follow-up period was 29 months, Twenty-seven patients (84.4$\%$) were followed up over 5 years. Radiotherapy was delivered with 6 MV photons to the primary laryngeal tumor and regional iymphatics with shrinking field technique. Ail patients received radiotherapy under conventional fractionated schedule (once a day). Median total tumor dose was 70.2 Gy (range, 55.8 to 75.6 Gy) on primary or gross tumor lesion. Thirteen patients had Induction chemotherapy with cisplatln and 5-fluorouracil (1-3 cycles). Patient distribution, according to the different stages, were as follows: stage I, 5/32 (15.6$\%$): stage II, 10/32 (31.3$\%$); stage III, 8/32 (25$\%$): stage IV, 9/32 (28.1$\%$). Results :The 5-year overall survival rate of the whole series (32 patients) was 51.7$\%$. The overall survival rate at 5-years was 80$\%$ in stage I, 66.7$\%$ in stage II, 42.9$\%$ in stage III, 25$\%$ in stage IV (p=0.0958). The S-year local control rates after radiotherapy were as fellows: stage I, 100$\%$; stage II, 60$\%$ stage III, 62.5$\%$; stage IV, 44.4$\%$ (p=0.233). Overall vocal preservation rates was 65.6$\%$, 100% In stage I, 70% in stage II, 62.5$\%$ In stage III, 44.4$\%$ in stage IV (p=0.210). There was no statistical significance in survival and local control rate between neoadjuvant chemotherapy followed by radiotherapy group and radiotherapy alone group. Severe laryngeal edema was found in 2 cases after radiotllerapy, emergent tracheostomy was done. Four patients were died from distant metastsis, . three in lung, one in brain. Double primary tumor was found in 2 cases, one in lung (metachronous), another in thyroid (synchronous). Ulcerative lesions were revealed as unfavorable prognostic factor ( p=0.0215), and radiation dose (more or less than 70.2 Gy) was an important factor on survival (p=0.002). Conclusion : The role of radiotherapy treatment of supraglottic carcinoma is to important factor on survival and to preserve the laryngeal function. Based on our data and other studies, early and moderately advanced supragiottic carcinomas could be successfully treated with either consewative surgery or radiotherapy alone. Both modalities showed similar results in survival and vocal preservation. For the advanced cases, radiotherapy alone is Inadequate for curative aim and surgery combined with radiotherapy should be done in operable patients. When patients refuse operation or want to preserve vocal function, or for the patients with inoperable medical conditions, combined chemoradiotherapy (concurrent) or altered fractionated radiotherapy with or without radiosensitizer should be taken into consideration in future.

• The Korean Journal of Pain
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• v.33 no.4
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• pp.378-385
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• 2020

Background: The thoracic paravertebral block is an effective analgesic technique for postoperative pain management after breast surgery. The ultrasound-guided retrolaminar block (RLB) is a safer alternative to conventional paravertebral block. Thus, we assessed the analgesic efficacy of ultrasound-guided RLB for postoperative pain management after breast surgery. Methods: Patients requiring breast surgery were randomly allocated to group C (retrolaminar injection with saline) and group R (RLB with local anesthetic mixture). The RLB was performed at the level of T3 with local anesthetic mixture (0.75% ropivacaine 20 mL + 2% lidocaine 10 mL) under general anesthesia before the skin incision. The primary outcome was cumulative morphine consumption using intravenous patient-controlled analgesia (IV-PCA) at 24 hour postoperatively. The secondary outcomes were the visual analogue scale (VAS) scores at 1, 6, 24, and 48 hour postoperatively and the occurrence of adverse events and patient satisfaction after the surgery. Results: Forty-six patients were included, 24 in group C and 22 in group R. The cumulative morphine consumption using IV-PCA did not differ between the two groups (P = 0.631). The intraoperative use of remifentanil was higher in group C than in group R (P = 0.025). The resting and coughing VAS scores at 1 hour postoperatively were higher in group R than in group C (P = 0.011, P = 0.004). The incidence of adverse events and patient satisfaction was not significantly different between the two groups. Conclusions: A single injection of ultrasound-guided RLB did not reduce postoperative analgesic requirements following breast surgery.

• Resources Recycling
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• v.16 no.2 s.76
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• pp.23-31
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• 2007

In this study, the crystallization of neodymium carbonate from neodymium chloride solution by addition of ammonium bicarbonate was investigated. The concentration of reactants such as neodymium chloride and ammonium bicarbonate, and reaction temperature play an important part in order to obtain the crystal of neodymium carbonate. It seemed that amorphous neodymium carbonate was prepared by aggregation of primary particles formed through nucleation. If reaction rate was increased by increasing the concentration of reactants and reaction temperature, then neodymium carbonate crystal could be obtained. Lanthanite-type neodymium carbonate[$Nd_2(CO_3)_3{\cdot}8H_2O$] and tengerite-type neodymium carbonate[$Nd_2(CO_3)_3{\cdot}2.5H_2O$] could be obtained with reaction renditions. Lanthanite-type neodymium carbonate was sensitive to temperature. The thermal decomposition of neodymium carbonate contained the processes or dehydration, decarbonation and crystalization of $Nd_2O_3$. The shape of lanthanite-type neodymium carbonate was irregular lump type, and tengerite-type neodymium carbonate had the shape of needle type. The shape of $Nd_2O_3$ was affected by the shape of neodymium carbonate.