• Journal of Electrical Engineering and Technology
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• v.13 no.2
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• pp.936-942
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• 2018

The diagnostic multi-leaf collimator preventing unnecessary dose from entering into patients during the diagnostic examination was made in this study. The movement of the entire 50 leaves was embodied with the group of 25 ones thereof configured in a pair facing each other on the left and right of the median line. Dimensions of the length, width, and height of each shielding leaf were $5{\times}0.5{\times}0.5cm^3$ resulting in the maximum boost field of $10{\times}10cm^2$. The material of multi-leaf collimator had the excellence on the machinability with the use of the SKD-11 alloy tool steel having the high wear resistance against frequent movement, and it was devised to control both-side's shielding leaves by moving 2 motors unlike existing remedial multi-leaf collimator that use as many motors as the number of 50 shielding leaves. Thereafter, the transmission dose of leaves, cross-leaf leakage dose, and inter-leaf leakage dose were measured by the developed multi-leaf collimator attached to X-ray equipment. An ionization chamber was used to detect doses there from, and the comparative analysis was carried out by means of the radiographic film that was easy to detect the dose leakage in between each leaf. Results obtained from the test conducted in comparative analysis yielded approximately 98%, 96%, and 94% of shielding efficiency realized at each level of energy of 80kV, 100kV, and 120kV it was confirmed there was no dose leakage resulted from the varied level of irradiation energy. Thus the multi-leaf collimator to be developed based on this study is thought that it could fully reduce the unnecessary dose to patients in the diagnostic test and the shielding efficiency thereof is expected to be increasing if it is made in a miniaturized form with a way of increasing the thickness of each leaf later for an extended application to general diagnostic purposes.

• Clinical and Experimental Reproductive Medicine
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• v.37 no.3
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• pp.245-251
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• 2010

Objective: Human sperm nucleus DNA damage may negatively affect pregnancy outcome, and the spermatozoa of infertile men have more DNA damage than that of fertile men. The aim of this study was to evaluate the effect of microsurgical varicocelectomy on human sperm nucleus DNA integrity. Methods: We reviewed the medical records of 18 subfertile male patients who underwent microsurgical varicocelectomy at our hospital from April 2006 to April 2007. Varicocele was diagnosed by physical examination and Doppler ultrasound. Standard semen analysis was performed in 18 patients before and 4 months after microsurgical varicoceletcomy using a computer assisted semen analyzer. Sperm nucleus DNA integrity was assessed by a single-cell gel electrophoresis (comet assay). Results: No recurrence of varicocele was observed after 4 months later. The DNA fragmentation index improved after varicocelectomy compared with pre-operatively (19.3 versus 13.7%, respectively, p<0.05). Semen analysis parameters (total count, concentration, motile sperm, viability, strict morphology) increased after varicocelectomy, but the difference did not reach statistical significance. Conclusion: Our data suggest that microsurgical varicocelectomy can improve semen analysis parameters and human sperm nucleus DNA integrity in infertile men with varicocele.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.3
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• pp.516-520
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• 2002

This study was designed to investigate the hepatoprotective effects of Semisulcospira libertina and garlic on the acute hepatotoxicity induced by carbon tetrachloride (CCl$_4$) of rats. Male Sprague-Dawley rats weighing 200∼220g were pretreated with dehydrated powder of Semisulcospira libertina (2.1 g/kg, po; SL) and dehydrated powder mixture of Semisulcospira libertina and garlic (3g/kg, 7:3 ratio, po; SG) once daily for 3 consecutive days, and then given a single dose of CCl$_4$(1g/kg in 5ml/kg corn oil, po) and liver function was determined 24 hrs later. Liver damage was assessed by quantitating activities of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), sorbitol dehydrogenase (SDH) and alkaline phosphatase (ALP) as well as by histopathological examination. Pretreatments with SL and SG significantly decleased CCl$_4$-elevated ALT (48% and 61% respectively), AST (32% and 47%) and SDH (51% and 76%), but had no effect on ALP. SL and SG had revealed hepatoprotective effects against CCl$_4$-induced histopathological changes such as severe necrosis, inflammatory cell infiltration and congestion in the central gene of hepatic lobule. These findings demonstrate that SL and SG may haute the hepatoprotective effect on CCl$_4$-induced liver damage.

• Restorative Dentistry and Endodontics
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• v.23 no.1
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• pp.366-378
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• 1998

Thermocondensation root canal filling technique have been used to fill accessary canals or to obtain homogeneous root caral fillings. But these thermocondensation technique inevitably produce heat in the canal which can be transmitted through the dentin and cementum and consequently damage periodontal ligamental cells and osteoblasts. In this study, System $B^{TM}$(Analytic technology, WA.D.S.A.) was used to evaluate the reaction of periodontal ligament tissue to "Continous Wave condensation technique" introduced by Buchanan, and the transmitted root surface temperature was measured according to measured root thicknesses. 12 Mandibular incisors of two adult dogs were used for the experiment. 6 controls were filled by lateral condensation technique with sealer.3 specimens were apically filled by Continuous Wave technique at $200^{\circ}C$ for 5 seconds and remaining 3 specimens were additionally backfilled using System $B^{TM}$(Analytic technology, WA.D.S.A.) was used to evaluate the reaction of periodontal ligament tissue to "Continous Wave condensation technique" introduced by Buchanan, and the transmitted root surface temperature was measured according to measured root thicknesses. 12 Mandibular incisors of two adult dogs were used for the experiment. 6 controls were filled by lateral condensation technique with sealer.3 specimens were apically filled by Continuous Wave technique at $200^{\circ}C$ for 5 seconds and remaining 3 specimens were additionally backfilled using System $B^{TM}$ at $100^{\circ}C$ for 20 seconds. Six weeks later, the dogs were sacrificed and the teeth stained with Hematoxylin and Eosin for histologic examination. 6 extracted human teeth were used to measure the transmitted temperature. After cutting off the crown, the canals were prepared and divided into 3 groups with root thickness of 1.5mm, 1.0mm, 0.5mm, 2 teeth in each group. Inside each root canal, System $B^{TM}$ was heated as with the temperature for the apically condensed and the back filled group, and the transmitted heat was measured on the external surface of the root. The temperature of System $B^{TM}$ heat spreader at $200^{\circ}C$ and $100^{\circ}C$ was also measured at root temperature. It can be concluded as follows: 1. In the thin area (200-$250{\mu}m$) of the root, root resorption could be seen even with heating at $200^{\circ}C$ for 5 seconds. 2. When the spreader was heated at $200^{\circ}C$ for 5 seconds and additionally at $100^{\circ}C$ for 20 seconds for backfill, all teeth showed root resorption regardless of their root thickness. 3. The transmitted external root surface temperature was higher as the root thickness decreased and as the heating time increased. In the thermocompaction technique using System $B^{TM}$, the spreader should be heated for the minimal time and used only in the apical area. The heated spreader shouldn't inserted to the binding point of the canal and backfilling should be done with other means of minimally heated gutta percha technique.

• Journal of Environmental Health Sciences
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• v.49 no.3
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• pp.159-168
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• 2023

Background: An ongoing environmental exposure assessment of humidifier disinfectants (HDs) has been conducted since November 2011 among individuals who experienced HD exposure-related adverse health effects. It is being performed in order to determine and quantify exposure to humidifier disinfectants in victims and their families. To date, the assessment has encompassed Cycles I-to-V. There is no report summarizing the characteristics of the subjects from the overall cycles. Objectives: We intended to examine the individual characteristics related to demographics, HD usage, and HD exposure using integrated data from Cycles I-to-V of the environmental exposure assessment of HDs and the changes with the cycles. Methods: We included 7,543 individuals who participated in Cycles I-to-V of the environmental exposure assessment of HDs. We summarized the participants' characteristics regarding their demographics (e.g., sex, education level, and age), HD usage history (e.g., product name, ingredient, and frequency of HD use), and HD exposure (e.g., daily time of HD use, cumulative time of HD use, and exposure intensity). In addition, their characteristics were compared across the cycles of the exposure assessment. Results: Among the 7,543 participants from Cycles I-to-V, there were more male participants than females (51.05% overall), except for Cycles I and III. Across all cycles, a higher proportion of survivors was observed than deceased individuals. While PHMG was the most prevalent ingredient in HDs throughout all the cycles, its proportion gradually decreased over the course of the examination cycles. Participants in Cycle I reported longer daily times of HD use compared to those in the subsequent cycles. On the other hand, cumulative time of HD use was shorter in the earlier cycles than in the later cycles. Conclusions: Using the integrated data from the full cycles of the environmental exposure assessment, this study identified changes in demographic characteristics as well as the HD exposure characteristics between the participants across different cycles.

• 한국노년학
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• v.32 no.2
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• pp.559-576
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• 2012

This research aims to address the effect of Guided Autobiography(GAB) on ego-integrity, depression and life-satisfaction in the elderly and to investigate psychological changes and experiences on the senior subject. 20 subjects participated weekly autobiography writing sessions in a senior academy in the S city for 13 weeks. In this research, we carried out examination on ego-integrity, depression test, and life-satisfaction survey were performed before and after the writing sessions for a quantitative analysis, which was later investigated through a 'corresponding sample T-test'. Based on the results of the above mentioned tests, the qualitative analysis was conducted through an individual sessions with 5 selected participants. The results of this research are summarized as following. First, ego-integrity showed satisfactorily meaningful difference between pre- and post-GAB writing. The participants recollected the past repent and revisited unresolved issues in their lives. The subjects were able to accept these past misdemeanors and appreciate their lives. GAB indeed helped improving ego-integrity. Second, the hypothesis that GAB writing will help decrease depression was accepted. 2-page weekly writing assignments enabled the participants think of joyful moments in their past, and showed decrease the symptoms of depression. Third, this study revealed that GAB writing improved life- satisfaction. The participants learned to express gratitude and peace in their mind. The happy feeling and optimistic thoughts enhanced their satisfaction of life in turn. In addition, it turned out that the effects of GAB were more drastic in group sessions than in individual writings. Interpersonal interactions in group sessions encouraged the exchange of positive feedback, thereby helping them reflect themselves positively.

• Journal of The Korean Ophthalmological Society
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• v.60 no.5
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• pp.480-485
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• 2019

Purpose: We report a case of postoperative endophthalmitis in the cataract patient, associated with removal of an intralenticular foreign body that had remained in place without symptoms for 20 years. Case summary: A 45-year-old male visited our outpatient clinic complaining of gradual visual loss in his right eye over the past 3 months. In slit-lamp examinations, anterior capsular opacification, nuclear sclerosis, and posterior subcapsular opacity were observed in the right eye. Twenty years before, a tiny metallic projectile had hit his right eye, but slit-lamp examination at the time of injury did not reveal any intraocular foreign body. We decided to undergo cataract surgery. During phacoemulsification, a metallic foreign body was found in the lens and safely removed; then an intraocular lens was implanted. As hypopyon was evident 3 days later, we injected intravitreal antibiotics and applied fortified antibiotic eye drops to the right eye. The anterior chamber inflammation improved and the best-corrected visual acuity recovered to 1.0. Conclusions: Surgeon should be aware of that endophthalmitis could develop after cataract surgery with removal of an intralenticular foreign body that had been in place for 20 years. But did not trigger inflammation or cause any symptoms as the cataract progressed.

• Korean Journal of Radiology
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• v.24 no.9
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• pp.903-911
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• 2023

Objective: Regrowth after radiofrequency ablation (RFA) of symptomatic large thyroid nodules, initially treated as benign, sometimes turns out to be malignancies. This study aimed to assess the ultrasound (US) characteristics of thyroid nodules initially treated as benign with RFA and later diagnosed as cancers, predictive factors for cancers masquerading as benign, and methods to avoid RFA in these cancers. Materials and Methods: We reviewed the medical records of 134 consecutive patients with 148 nodules who underwent RFA between February 2008 and November 2016 for the debulking of symptomatic thyroid nodules diagnosed as benign using US-guided biopsy. We investigated the pre-RFA characteristics of the thyroid nodules, changes at follow-up after RFA, and the final surgical pathology. Results: Nodule regrowth after RFA was observed in 36 (24.3%) of the 148 benign nodules. Twenty-two of the 36 nodules were surgically removed, and malignancies were confirmed in seven (19.4% of 36). Of the 22 nodules removed surgically, pre-RFA median volume (range) was significantly larger for malignant nodules than for benign nodules: 22.4 (13.9-84.5) vs. 13.4 (7.3-16.8) mL (P = 0.04). There was no significant difference in the regrowth interval between benign and malignant nodules (P = 0.49). The median volume reduction rate (range) at 12 months was significantly lower for malignant nodules than for benign nodules (51.4% [0-57.8] vs. 83.8% [47.9-89.6]) (P = 0.01). The pre-RFA benignity of all seven malignant nodules was confirmed using two US-guided fine-needle aspirations (FNAs), except for one nodule, which was confirmed using US-guided core-needle biopsy (CNB). Regrown malignant nodules were diagnosed as suspicious follicular neoplasms by CNB. Histological examination of the malignant nodules revealed follicular thyroid carcinomas, except for one follicular variant, a papillary thyroid carcinoma. Conclusion: Symptomatic large benign thyroid nodules showing regrowth or suboptimal reduction after RFA may have malignant potential. The confirmation of these nodules is better with CNB than with FNA.

• Journal of Chest Surgery
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• v.34 no.11
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• pp.823-830
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• 2001

Background: Paraplegia is a serious complication of thoracic or thoracoabdominal aortic operations, which is related to ischemic injury of the spinal cord induced by low perfusion pressure during cross clamping of the aorta. Ischemic preconditioning of heart or brain with reversible sublethal ischemic injury induces resistance to subsequent lethal ischemia. The aim of this study is to investigate whether ischemic tolerance could be induced by the preconditioning of the spinal cord using swine model. Material and Method: The animals were randomly assigned to three groups: sham group(n=3), control group(n=6) and pre-conditioning group(n=8). In the sham group, we performed the left thoracotomy only without any ischemic injury. In the preconditioning group, the swine received reversible spinal cord ischemic injury by aortic clamping for 20 minutes, whereas control group had no previous aortic cross- clamping. Forty-eight hours later, the aorta was clamped for 30 minutes in both groups. Neurological examination was done 24 hours later, then the animals were euthanized for histopathology and malonedialdehyde(MDA) spectrophotometry assay of the spinal cord. Result: Statistically significant difference in neurological outcome was observed between the control and preconditioning groups at 24 hours after ischemic injury. The incidence of paraplegia and severe paresis was 100% in the control group, and 62.5% in the preconditing group(p=0.028). There was no statistically significant difference in histopathology and MDA assay of the ischemic spinal cord between these two groups with borderline statistical difference in MDA assay(p=0.0745). Conclusion: In the present swine study, ischemic preconditioning could induce tolerance against 30 minute ischemic insult of the spinal cord, although the animals did not completely recover(stand-up or walk). We expect that combining this preconditioning with other currently existing protection methods might lead to a synergistic effect, which warrants further investigation.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.1 no.1
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• pp.100-106
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• 1998

Purpose: Ceftriaxone, a potent parenteral third-generation semisynthetic cephalosporin is widely used for the treatment of a variety of bacterial infections in both children and adult. Review of recent data indicates that ceftriaxone treatment has been associated with the development of reversible biliary pseudolithiasis and that is thought by many to be a benign process. Despite, several reports describe patients with ceftriaxone pseudolithiasis who required cholecystectomy for presumed acute cholecystitis. In this study we evaluated the incidence, risk factors, and prognosis of gallbladder pseudolithiasis after ceftriaxone treatment. Methods: Between march, 1997 and January, 1998, any child admitted to the Children's hospital of National University of Seoul and prescribed ceftriaxone for probable or definite bacterial infection were eligible for the study. 21 of them had ultrasound examination on the 2~12 days later after the start of ceftriaxone treatment, 8 of whom documented gallbladder precipitates or pseudolithiasis during treatment by serial abdominal ultrasound. Repeat abdominal ultrasound was performed 10~80 days later after the end of ceftriaxone treatment. The children with underlying liver disease or decreased renal function were excluded in this study. Results: 1) 21 children had ultrasound examinations of gallbladder during ceftriaxone treatment and 8 (38%) of them acquired pseudolithiasis. 2) The patients who developed gallbladder pseudolithiasis were significantly older ($6.3{\pm}2.9$ yr. vs $2.2{\pm}3.1$ yr.)(p<0.05), and older than 24 months were probably the significant risk associated with this phenomenon (p<0.05). However, no significant differences in sex, type of infection, fasting, and ceftriaxone treatment regimen (dose, duration of therapy). 3) The abnormality found on gallbladder ultrasonography was a strikingly hyperechogenic material with post-acoustic shadowing in 5 patients without post-acoustic shadowing in 3 patients 4) Follow up of gallbladder ultrasound was performed in 6 patients after cessation of ceftriaxone treatment. Sonographic abnormalities completely resolved within 14 days post cessation of therapy in 2 patients; 30 days, 1 patient; 80 days, 3 patients. Conclusions: We suggest that routine abdominal ultrasound should be considered in all children who received high dose ceftriaxone in more than 24 months of age and developed hepatobiliary symptoms during or just after ceftriaxone treatment.