• Childhood Kidney Diseases
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• v.1 no.1
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• pp.46-52
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• 1997

Urinary tract infection (UTI) in children has been known to be a cause of renal damage, leading to scar formation, hypertension and renal failure. And vesico-ureteral reflex (VUR), frequently accompanying UTI in young children, has been incriminated as the main factor causing scar formation. This retrospective study has been undertaken to see the relationship among UTI, VUR and renal scar formation. Study population consisted of 291 children (boy 134, girl 42) with UTI, who have been admitted to the Pediatric Department of Kyungpook University Hospital during 6 1/2 year period from January 1990 to June 1996. VUR was diagnosed by VCUG and renal scar by ultrasonogram, DMSA scan (or DMSA SPECT) and IVP. The following result were obtained. Sexual difference showed male predominance (male to female, 134:42) below 1 year of age, and female predominance (male to female, 11:35) over 5 years of age were rioted. VUR has been found in 64 children (22%) and the degree of reflux, classfied by the method proposed by 'International Reflux Study in Children', were as follows ; Grade I : 4.0%, Grade II : 3.0%, Grade III : 2.7%, Grade IV : 5.8% and Grade V : 6.2%. There was no sexual difference E.coli was the most predominant infecting agent occurring in 167 children (57%), and end-stage renal failure was diagnosed at the time of first admission in 5 children with Grade V VUR. Renal scar has been noted in 49 out of 582 kidneys (8.4%), and the incidence of scar foramation according to the degree of VUR were as follow ; Grade 0 (No reflux) : 1.2%, Grade I : 6.7%, Grade II 27.3%, Grade III 29.4%, Grade IV : 57.1%, and Grade V : 100%. In summary, present study shows that renal scar formation in UTI has close correlation with the severity of VUR occurring more frequently in severe reflux, so that early diagnosis and proper treatment of UTI and VUR is of paramount importance in preventing renal damage in children with UTI.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.8 no.2
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• pp.150-156
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• 2005

Purpose: We divided the children diagnosed with intususception into three different age groups and compared the clinical symptoms and treatment outcomes in order to analysis diagnosis and treatment of Intusussception. Methods: A retrospective chart review was established of 159 patients diagnosed with intussuception who had been admitted to Department of Pediatrics and General Surgery, Bundang CHA hospital from January, 2000 to May, 2004. We divided the patients into three groups, according to their age. Those who were under five months of age (group I; 21 patients), those between 5~11 months of age (group II; 61 patients), and those older than 11 months of age (group III; 77 patients). Then we compared the age, sex, seasonal distribution of occurrence, the cause, the clinical features, radiologic review, the type of intusussception, surgical methods, recurrence rate and treatment outcomes, among these three groups. Results: On comparing the clinical symptoms and signs among the three groups, the most common major clinical symptom and sign was irritabiltity in all three groups. Vomiting with irritability was statistically more common in group I (p<0.05) and bloody stool was most frequent in group III. The average time taken until a diagnosis was made after the symptom onset was, 21 hours in group I, 20 hours in group II and 22 hours in group III. Which showed no significant difference. But there was a higher rate of delayed diagnosis in group I, which took over 48 hours until the diagnosis was made (group I; 23.8%, group II; 4.9%, group III; 7.8%). Simple abdominal X-rays showed more frequent instances of intestinal obstruction in group I (p<0.05). The primary treatment done was barium enema which showed a failure rate of 52.4% in group I, 26.2% in group II and 14.3% in group III. Showing the highest failure rate in group I. Conclusion: The youngest group had vague symptoms which lead to delayed diagnosis and more frequent surgical procedures. As so, we advocate the importance of further evaluation and close observation, considering intussusception in children with symptoms of irritability and vomiting, especially in the early infant group.

• The Journal of Korean Academy of Prosthodontics
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• v.46 no.5
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• pp.479-489
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• 2008

Statement of the problem: Under anatomical limitations on maxillary posterior region, a poor crown-to root ratio acting on dental implants can result in undesirable stress in surrounding bone, which in turn can cause bone defects and eventual failure of implants. Purpose: The purpose is to compare stress distribution due to different crown-root ratio and effect of splinting between natural teeth and implants in maxillary molar area under different loads. Material and methods: Analysis of stress arising supporting bone of the natural teeth and the implant was made with 3-dimensional finite element method. The model simulated naturel teeth was made with 2nd premolar and 1st molar in the maxillary molar region (Model T). The model simulated implants placed on same positions with two parallel implants of Straumann Dental Implant cemented abutment (Model I). Each model was designed in different crown-root ratio (0.7:1, 1:1, 1.25:1) and set cement type gold crown to make it non-splinted or splinted. After that, 300 N force was loaded to each model in five ways (Load 1: middle of occlusal table, Load 2: middle of buccal cusp, Load 3: middle of lingual cusp, Load 4: horizontal load to buccal cusp of anterior abutment only, Load 5: horizontal load to middle of buccal cusp of each abutment), and stress distribution was analyzed. Results and conclusion: On all occasions, stress was concentrated at the cervical region of the implant. Under load 1, 2 and 3, stress was not increased even when crown-root ratio increases, but under load 4 and 5, when crown-root ratio increases, stress also increased. There was difference in stress values between natural teeth and implants when crown-root ratio gradually increases; In case of natural teeth, splinting decreased stress under vertical and horizontal loads. In case of implants, splinting decreased stress under vertical loads 1,2 and 3, but increased maximal stress under loads 2 and 3. Under horizontal loads, splinting decreased stress, however the effect of splinting decreased under load 5 than load 4. Furthermore, the stress was increased, when crown-root ratio is 1.25:1. Clinical implications: This limited finite element study suggests that the stress on supporting bone may be increased under non-axial loads and poor crown-root ratio. Under poor crown-root ratio, excessive stress was generated at the cervical region of the implant, and decreased splinting effect for stress distribution, which can be related to clinical failure.

• Journal of Chest Surgery
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• v.38 no.2 s.247
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• pp.132-138
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• 2005

Background: Mitral valve repair (MVP) is the optimal procedure for mitral regurgitation (MR), however, failure and subsequent reoperations are the limitations. The current study assessed the procedure in relation to the primary valve related causes of recurrent MR. Material and Method: MR was treated in 493 patients undergoing MVP from January of 1994 to January of 2002. The causes of MR were degenerative $(n=252,\;51.5\%),$ rheumatic $(n=156,\; 31.6\%),$ and others $(n=85,\; 16.9\%).$ Surgery comprised 446 ring annuloplasties $(90.5\%),$ 227 new chordae formations $(46\%),$ 125 quadriangular resections $(25.3\%),$ 28 chordae transfers $(5.7\%),$ and 8 Alfieri's stitches $(1.6\%).$ The mean follow up was $29.04\pm22.81$ months. Result: There were 5 early $(1.01\%)$, and 5 late deaths $(1.01\%).$ The reoperation rate was $1.42\%$. There were 45 $(9.1\%)$ recurrent MR (grade III or IV). Of these, 24 were procedure related including incomplete repair (n=14), discordant new chordae length (n=8) and others (n=2). In 21 patients, the cause was valve related including rheumatic disease progression (n=10), recurrent chordae elongation or prolapse (n=5) and others (n=6). Severe MR was higher after incomplete repair (p < 0.001), and valve related failure strongly correlated with rheumatic progression (p < 0.05). Conclusion: Since completeness of operation is the prime risk factor that determine the repair durability, intra-operative assessment of the initial repair with trans-esophageal echocardiography is essential.

• Journal of Chest Surgery
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• v.34 no.6
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• pp.477-484
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• 2001

Background: Initial symptoms for esophageal perforation have not been clarified, but when there is no early diagnosis and proper treatment to follow immediately after the diagnosis, it is fatal for the patients. Therefore, this study attempted to discover the factors that influence the prognosis of esophageal perforation to contribute to the improvement of the treatment result. Material and Method: The subjects of this study are 32 patients who came to the hospital with esophageal perforation from October, 1984 to June, 2000. This study examined the items for clinical observation such as patients' sex, age, cause of the perforation, perforation site, the time spent until the beginning of the treatment, symptoms caused by the perforation and its complication, and treatment methods. This study tried to find out the relationship between the survival of patients and each item. Result: There were 24 male and 8 female patients and their mean age was 49.7+16.4. For the causes of perforation, there were 14 cases(43%) of iatrogenic perforation, which ranked first, caused by the medical instrument operation and surgical damage. As for the perforation sites, thoracic esophagus was the most common site(26 cases of 81.2%) and chest pain was the most frequent symptom. The complication caused by esophageal perforation showed the highest cases in the order of mediastinitis, empyema, sepsis and peritonitis. After the treatment, there were 23 cases of survival and 9 cases of mortality. The total mortality rate was 28.1% and the main causes of mortality were sepsis and acute respiratory distress syndrome(ARDS). As for the treatment, 8 cases(25.0%) treated the perforation successfully using conservative treatment only. As for the surgical treatment, there were 5 cases(15.6%) of cervical drainage, 7 cases (21.8%) of primary repair and 12 cases(37.5%) of esophageal reconstruction after performing an exclusion-diversion. There were 18 cases(56.2%) of complete treatment of esophageal perforation at its initial treatment and in 14 cases(43.8%) of treatment failure at its initial treatment, patients were completely cured in the next treatment stage or died during the treatment. The cases of perforation in thoracic esophagus, complication into severe mediastinitis or sepsis and the cases of failure at initial treatment showed a statistically significant mortality rate (p<0.05).

• Radiation Oncology Journal
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• v.13 no.3
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• pp.259-266
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• 1995

Purpose : The aim of this study is to analyze the survival rate, treatment failure and complication of radiation therapy alone in stage III uterine cervical cancer. Materials and Methods : From January 1980 through December 1985, 227 patients with stage III uterine cervical cancer treated with radiation therapy at Kosin Medical Center were retrospectively studied. Among 227 patients, 72 patients($317{\%}$) were stage IIIa, and 155 patients($68.3{\%}$) were stage IIIb according to FIGO classification. Age distribution was 32-71 years (median: 62 years). Sixty nine patients($95.8{\%}$) in stage IIIa and 150 patient ($96.8{\%}$) in stage IIIb were squamous cell carcinoma. pelvic lymph node metastasis at initial diagnosis was 8 patients($11.1{\%}$) in stage IIIa and 29 patients($18.7{\%}$) in stage IIIb, Among 72 patients with stage IIIa, 36 patients ($50{\%}$) were treated with external radiation therapy alone by conventional technique (180-200 cGy/fr.) and 36 patients($50{\%}$) were treated with external radiation therapy with intracavitary radiotherapy(ICR) with $Cs^{137}$ sources, and among 155 patients with stage IIIb, 80 patients ($51.6{\%}$) were treated with external radiation therapy alone and 75 patients ($48.4{\%}$) were treated with external radiation therapy with ICR. Total radiation doses of stage IIIa and IIIb were 65-105 Gy(median: 78.5 Gy) and 65-125.5 Gy (median 83.5 Gy). Survival rate was calculated by life-table method. Results : Complete response rates were $58.3{\%}$(42 patients) in stage IIIa and $56.1{\%}$(87 patients) in stage IIIb. Overall 5 year survival rates were $57{\%}$ in stage IIIa and $40{\%}$ in stage IIIb. Five year survival rates by radiation technique in stage IIIa and IIIb were $64{\%},\;40{\%}$ in the group treated in combination of external radiation and ICR, and $50\%,\;40\%$ in the group of external radiation therapy alone(P=NS). Five year survival rates by response of radiation therapy in stage IIIa and IIIb were $90\%,\;66\%$ in responder group and $10\%,\;7\%$ in non-responder group (P<0.001) There were statistically no significant differences of 5 year survival rate by total radiation doses and external radiation doses(40 Gy vs 50 Gy) of whole or true pelvis in stage IIIa and IIIb(P=NS). Treatment failures rates were $40.3\%$(29 patients) in stage IIla and $57.4\%$(89 patients) in stage IIIb. 17 patients ($23.6\%$) in stage IIIa and 46 patients ($29.7\%$) in stage IIIb experienced complications. Total radiation doses more than 85 Gy produced serious complication in both stage IIIa($50\%$) and IIIb($50\%$). Serious complication rates were higher in group received external radiation doses of 50 Gy than 40 Gy to whole or true pelvis in stage IIIa and IIIb. Serious rectal complication developed in rectal doses more than 65 Gy, and serious bladder complication developed in bladder doses more than 75 Gy. Major cause of death was cachexia due to locoregional failure in both stage IIIa($34.7\%$) and IIIb($43.9\%$). Conclusion : From this study, we found that external radiation therapy with ICR was found to have a tendency to be superior to external radiation therapy alone in survival rate, local control rate and complication rate but not different in statistics, and external radiation doses of 50 Gy than 40 Gy to whole or true pelvis produced serious rectal and bladder complications in stage III uterine cervical cancer.

• Korean Journal of Heritage: History & Science
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• v.46 no.3
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• pp.212-228
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• 2013

Stone cultural heritages are repaired by the use of metal stiffeners. The problem is that this type of repair has been based on the experience of workers without specific guidelines and has caused various problems. This is to suggest the structural reinforcement and behavioral characteristics of metal rods to minimize the secondary damage of materials and have the specimens tested and verified to establish the guidelines on how to insert metal stiffeners. When only epoxy resin is applied to the cut surface, only 70% of the properties of the parent material are regenerated and it is required to structurally reinforce the metal stiffener for the remaining 30%. The metal rod is under the structural behavior after the brittle failure of stone material and the structural behavior does not occur when the metal stiffener is below 0.251%. When it accounts for over 0.5%, it achieves structural reinforcement, but causes secondary damage of parent materials. The appropriate ratio of metal stiffener for the stone material with the strength of $1,500kgf/cm^2$, therefore, should be between 0.283% and 0.377% of the cross section of attached surface to achieve reversible fracture and ductility behavior. In addition, it is more effective to position the stiffeners at close intervals to achieve the peak stress of metal rod against bending load and inserting the stiffener into the upper secions is not structurally supportive, but would rather cause damage of the parent material. Thus, most stiffeners should be inserted into the lower part and some into the central part to work as a stable tensile material under the load stress. The dispersion effect of metal rods was influenced by the area of reinforcing rods and unrelated to their diameter. However, it ensures stability under the load stress to increase the number of stiffeners considering the cross section adhered when working on large-scale structures. The development length is engineered based upon the diameter of stiffener using the following formula: $l_d=\frac{a_tf_y}{u{\Sigma}_0}$. Also, helically-threaded reinforcing rods should be used to perform the behaviors as a structural material.

• Journal of Intelligence and Information Systems
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• v.27 no.1
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• pp.177-190
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• 2021

Due to the development of the fourth industrial revolution technology, efforts are being made to improve areas that humans cannot handle by utilizing artificial intelligence techniques such as machine learning. Although on-demand production companies also want to reduce corporate risks such as delays in delivery by predicting total production time for orders, they are having difficulty predicting this because the total production time is all different for each order. The Theory of Constraints (TOC) theory was developed to find the least efficient areas to increase order throughput and reduce order total cost, but failed to provide a forecast of total production time. Order production varies from order to order due to various customer needs, so the total production time of individual orders can be measured postmortem, but it is difficult to predict in advance. The total measured production time of existing orders is also different, which has limitations that cannot be used as standard time. As a result, experienced managers rely on persimmons rather than on the use of the system, while inexperienced managers use simple management indicators (e.g., 60 days total production time for raw materials, 90 days total production time for steel plates, etc.). Too fast work instructions based on imperfections or indicators cause congestion, which leads to productivity degradation, and too late leads to increased production costs or failure to meet delivery dates due to emergency processing. Failure to meet the deadline will result in compensation for delayed compensation or adversely affect business and collection sectors. In this study, to address these problems, an entity that operates an order production system seeks to find a machine learning model that estimates the total production time of new orders. It uses orders, production, and process performance for materials used for machine learning. We compared and analyzed OLS, GLM Gamma, Extra Trees, and Random Forest algorithms as the best algorithms for estimating total production time and present the results.

• Journal of the korean academy of Pediatric Dentistry
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• v.37 no.2
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• pp.233-239
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• 2010

Space loss of dental arch can appear when the proper position of teeth within the dental arch changes by a certain cause, because the balance of force makes changes about tooth position as well as alignment. The causes of space loss include proximal caries, early extraction, congenital missing of a tooth and hypodontia, etc. Among those causes of space loss, congenital missing of a tooth is more rarely observed in the primary dentition than in the permanent dentition. Congenital missing in the primary dentition is associated with that in the permanent dentition. Furthermore, it can cause space problem, such as mesial tilting or drift of adjacent teeth, space loss for permanent successors and dental arch constriction, etc. Primary lateral incisors is the most commonly involved, in the maxilla rather than in the mandible, but primary canine is rarely reported. In this patient, who visited the department of pediatric dentistry at Yonsei university dental hospital, it was observed that the maxillary right primary canine was congenitally missing and an odontoma was found insteadly. However, neither the space loss for the congenitally missing primary canine nor midline deviation is remarkable during the 2-year-10-month observation period. In addition, any clinical or radiographical symptom did not occur in spite of odontoma. Therefore, surgical enucleation of odontoma is planned according to the eruption of permanent lateral incisor or canine, unless eruption failure of permanent lateral incisor or canine nor cystic change around the odontoma is occurred. Through further evaluation, space maintainer or orthodontic treatment may be necessary.

• Journal of Chest Surgery
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• v.30 no.2
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• pp.137-145
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• 1997

From July 1983 to December 1993, total 112 consecutive mitral valve replacements in 107 patients were performed in patient with mitral valvular abnormalities. To estimate the risk factor related to operative death, all patient's perioperative data were reviewed retrospectively. Except 20 patients received concomitant aortic valve replacement and 2 patients had incomplete data, 85 patients were included in this study. Mean age were $37.3\pm$ 13.1 years ranging from 13 to 72 years. Thirty-seven patients were male and fourty-eight patients were female. Mean follow-up durations were $51.1\pm33.8$ months ranging from 6 months t 11 years. Patients in this study showed improvement in mean NYHA functional clssification, from $3.02\pm0.73$ to 1 $78\pm0.55,$ and also in cardiothoracic ratio, from 0.61 $\pm0.09$ to $0.58\pm0.08$ at 6 months follow-up after operation. Operative complications were detected in 23 patients(27.1 %) and common postoperative complications were rhythm disturbance in 7 cases, pulmonary complications in 6 cases and low cardiac output syndrome in 6 cases. Early mortality was 10.6%(n=9) and the most common cause of death was a congestive heart failure due to low cardiac output syndrome. Main cause of our higher operative mortality than other study was that operative mortality in the initial period of our mitral surgery was high(5 operative deaths among 19 mitral valve replacement from July 1983 to December 1985). Actuarial survival was 80.8% at 5 years, 71.8% at 11 years including operative deaths. Actuarial freedom from anticoagulant-related bleeding was 85.3% at 5 years, 78.3% at 11 years. 95.1% at 5 years and 88.8% at 11 years among the patient in this study were free from thromboembolism, and 97.5% at 5 years and 75.1% at 11 years were free from reoperation. Preoperative cardiothoracic ratio and patient's age were statistically significant operative risk factors.