• Korean Journal of Ichthyology
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• v.35 no.2
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• pp.91-100
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• 2023

The early life history of Silurus microdorsalis living in Jahocheon Stream was studied by observing egg and morphological development. Live fish were captured in June 2018, then reared in a circulating filtration system under a 14L : 10D photoperiod with a water temperature of 18℃. To artificially induce spawning, females were injected with 0.5 mL of Ovaprim (Syndel, Nanaimo, BC, Canada) per kg of body weight, and males were injected with 10,000 IU/kg body weight of human chorionic gonadotropin. Approximately 15 h later, eggs were artificially inseminated by the dry method. Mature eggs were light pale yellow, which separated them from immature eggs. Fertilized eggs were 2.16±0.06 mm (n=8) in diameter and fully hatched at 181 h after fertilization. The fertilization rate was 63.1±2.2%, and 10.0±3.7% of the embryos were malformed at 18℃. The rates of development were 181 h at 18℃, 109 h at 21℃, and 76 h at 24℃. The larval size immediately after hatching was 4.64±0.22 mm (n=8), and the larvae displayed negative phototaxis at 1 day after hatching. The total larval length on 7 days after hatching was 12.47±0.53 mm, with 25~30 basal anal fin rays and 14~16 basal caudal fin rays observed. The total larval length was 14.13±0.51 mm on 9 days after hatching, and approximately 90% of the black endoplasmic reticulum was deposited on the head and body. The dorsal fin had formed, and a single basal body was observed. On 15 days after hatching, the total larval length was 16.69±0.31 mm; the number of basal caudal fin rays (18 poles) was an integer because 2 dorsal fin basal rays and 60~63 anal fin basal rays were observed. The total larval length was 28.96±1.10 mm on 50 days after hatching; the numbers of caudal fins (n=18), dorsal fins (n=3), pectoral fins (n=11), and anal fin basal rays (n=67~73) were integers.

• Applied Microscopy
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• v.41 no.1
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• pp.47-53
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• 2011

Hair is an appendage of skin which protects the body from outer physical and chemical stimuli. Hair is generated from the hair follicle lying on a sunken basal layer of epidermis. Hair cycling, which regenerates hair follicles throughout the life time of the organism. Numerous kinds of factors which exist at the hair follicle have been reported to regulate hair cycling, Human growth hormone secreted from pituitary gland, initially demonstrated to accelerate organ's growth, has been reported to play a role in the biology of organ size determination. We investigated the effect of 6-histidines residues tagged at amino-terminus of human growth hormone using light and electronmicroscopic methods. Human growth hormone encapsulated in nano-liposome (LhGH) was used to find how LhGH affects hair follicle cycling of mouse (C57BL6/CrN). Distilled water as a negative control, 3% Minoxidil as a positive control, and LhGH were applied to mouse for weeks. LhGH increased the number of exposed hairs per given areas ($1mm^2$). This result was also confirmed using a different breed of mice which show natural hair loss in an old age (about 17 months after birth). When LhGH was applied for 3 weeks after natural hair loss, natural hair loss on these mice was prevented, However, the control group mice on which LhGH was not applied showed further hair loss. This result indicates that LhGH may stimulate hair cycling of mouse. In clusion, it is cleat that the LhGH increased the number of hair on mice and help the depilated skin to grow new hair follicles again.

• Journal of the Korean Chemical Society
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• v.51 no.1
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• pp.43-50
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• 2007

Liposomes having particle size from several tens to hundreds nanometers are efficient carriers for injectable drug delivery. Enhancement of liposome stability in bloodstream has been studied because of its relatively short circulation time and fast clearance from human body by reticuloendothelial system (RES) in blood vessel. In this study, new disaccharide-1,2-distearoyl-sn-glycero-3-phosphoethanolamine (DSPE) derivatives in which lactose or sucrose as the disaccharide molecule was conjugated covalently to DSPE were synthesized. Liposomes of which surface had disaccharide molecules were prepared by incorporating the disaccharide-DSPE into liposomes as one of their lipid components. Particle size of the prepared liposomes was approximately 100 nm. The liposomes of which surface were modified with the disaccharide-DSPE showed -25 mV of zeta potential value due to the presence of hydroxyl groups on their surface, while the unmodified control liposomes showed -10 mV of zeta potential value. Loading efficiency of model drug, doxorubicin, into liposomes was about 90%. Stability of the disaccharide-modified liposomes in vitro was evaluated by monitoring the amount of protein adsorption and particle size of the liposomes in serum. Disaccharide-modified liposomes were more stable in serum than unmodified control liposomes or polyethyleneglycol (PEG)-modified liposomes due to less adsorption of serum protein and hence less increase of their particle size. The liposomes of which surface was modified with disaccharide-DSPE conjugate can be used as long-circulating carriers for drugs having high toxicity or short half-life time due to their enhanced stability in blood circulatory system.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.36 no.5
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• pp.366-374
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• 2010

Introduction: This study evaluated the capability of silk fibroin (SF) and recombinant human bone morphogenetic protein-2 loaded SF (SF-BMP) as a bone defect replacement matrix when grafted in a calvarial bone defect of rats in vivo. Materials and Methods: A total 70 calvarial critical size defects (5.0 mm in diameter) made on 35 adult female Sprague-Dawley rats were used in this study. The defects were transplanted with (1) rhBMP-2 loaded silk fibroin graft (SF-BMP: 0.8+$10\;{\mu}g$), (2) Silk fibroin (SF: $10\;{\mu}g$), and (3) no graft material (Raw). The samples were evaluated with soft x-rays, alkaline phosphatase activity, calcium/phosphate quantification, histological and histomorphometric analysis at postoperative 4 and 8 weeks. Results: The SF-BMP group ($48.86{\pm}14.92%$) had a significantly higher mean percentage bone area than the SF group ($24.96{\pm}11.01%$) at postoperative 4 weeks.(P<0.05) In addition, the SF-BMP group ($40.01{\pm}12.43%$) had a higher % bone area at postoperative 8 weeks than the SF group ($33.26{\pm}5.15%$). The mean ratio of gray scale levels to the host bone showed that the SF-BMP group ($0.67{\pm}0.08$) had a higher mean ratio level than the SF group ($0.61{\pm}0.09$) at postoperative 8 weeks. These differences were not statistically significant.(P=0.168 and P=0.243, respectively) The ratio of the calcium and phosphate contents of the SF-BMP ($0.93{\pm}0.22$) group was lower than that of the SF ($1.90{\pm}1.42$) group at postoperative 4 weeks. However, the SF-BMP group ($0.75{\pm}0.31$) had a higher Ca/$PO_4$ ratio than the SF ($0.68{\pm}0.04$) at postoperative 8 weeks. These differences were not statistically significant.(P=0.126 and P=0.627, respectively) For the bone-specific alkaline phosphatase (ALP) activity, which is recognized as a reliable indicator of the osteoblast function, the SF-BMP ($23.71{\pm}8.60\;U/L$) groups had a significantly higher value than the SF group ($12.65{\pm}6.47\;U/L$) at postoperative 4 weeks.(P<0.05) At postoperative 8 weeks, the SF-BMP ($21.65{\pm}10.02\;U/L$) group had a lower bone-specific ALP activity than the SF group ($16.72{\pm}7.35\;U/L$). This difference was not statistically significant.(P=0.263) For the histological evaluation, the SF-BMP group revealed less inflammation, lower foreign body reactions and higher bone healing than the SF group at postoperative 4 and 8 weeks. The SF group revealed more foreign body reactions at postoperative 4 weeks. However, this immunogenic reaction decreased and the remnant of grafted material was observed at postoperative 8 weeks. For histomorphometric analysis, the SF-BMP group had a significantly longer bone length to total length ratio than those of the SF group at postoperative 4 and 8 weeks.(P<0.05) Conclusion: The rhBMP-2 loaded silk fibroin graft revealed fewer immunoreactions and inflammation as well as more new bone formation than the pure silk fibroin graft. Therefore, silk fibroin may be a candidate scaffold for tissue engineered bone regeneration.

• Journal of the Korean Society of Radiology
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• v.15 no.7
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• pp.965-973
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• 2021

Since radiation therapy is irradiated with high-energy X-rays in a variety of at least 20 Gy to 80 Gy, a high dose is administered to the local area where the tumor is located, and various side effects of some normal tissues are expected. Currently, in clinical practice, lead, a representative material, is used as an effort to shield normal tissues, but lead is classified as a heavy metal harmful to the human body, and a large amount of skin contact can cause poisoning. Therefore, this study intends to manufacture a measurement sheet that can compensate for the limitations of lead using the materials Tungsten, Brass, and Copper of the 3D printer of the FDM (Fused Deposition Modeling) method and to investigate the penetration performance. Tungsten mixed filament transmission measurement sheet size was 70 × 70 mm and thickness 1, 2, 4 mm using a 3D printer, and a linear accelerator (TrueBeam STx, S/N: 1187) was measured by irradiating 100 MU at SSD 100 cm and 5 cm in water using a water phantom, an ion chamber (FC-65G), and an elcetrometer (PTW UNIDOSE), and the permeability was evaluated. As a result of increasing the measurement sheet of each material by 1 mm, in the case of Tungsten sheet at 3.8 to 3.9 cm in 6 MV, the thickness of the lead shielding body was thinner than 6.5 cm, and in case of Tungsten sheet at 4.5 to 4.6 cm in 15 MV. The sheet was thinner than the existing lead shielding body thickness of 7 cm, and equivalent performance was confirmed. Through this study, the transmittance measurement sheet produced using Tungsten alloy filaments confirmed the possibility of transmission shielding in the high energy region. It has been confirmed that the usability as a substitute is also excellent. It is thought that it can be provided as basic data for the production of shielding agents with 3D printing technology in the future.

• Journal of Breast Disease
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• v.6 no.2
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• pp.52-59
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• 2018

Purpose: This study aimed to determine whether clinicopathological factors are potentially associated with successful breast-conserving surgery (BCS) after neoadjuvant chemotherapy (NAC) and develop a nomogram for predicting successful BCS candidates, focusing on those who are diagnosed with hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative tumors during the pre-NAC period. Methods: The training cohort included 239 patients with an HR-positive, HER2-negative tumor (${\geq}3cm$), and all of these patients had received NAC. Patients were excluded if they met any of the following criteria: diffuse, suspicious, malignant microcalcification (extent >4 cm); multicentric or multifocal breast cancer; inflammatory breast cancer; distant metastases at the time of diagnosis; excisional biopsy prior to NAC; and bilateral breast cancer. Multivariate logistic regression analysis was conducted to evaluate the possible predictors of BCS eligibility after NAC, and the regression model was used to develop the predicting nomogram. This nomogram was built using the training cohort (n=239) and was later validated with an independent validation cohort (n=123). Results: Small tumor size (p<0.001) at initial diagnosis, long distance from the nipple (p=0.002), high body mass index (p=0.001), and weak positivity for progesterone receptor (p=0.037) were found to be four independent predictors of an increased probability of BCS after NAC; further, these variables were used as covariates in developing the nomogram. For the training and validation cohorts, the areas under the receiver operating characteristic curve were 0.833 and 0.786, respectively; these values demonstrate the potential predictive power of this nomogram. Conclusion: This study established a new nomogram to predict successful BCS in patients with HR-positive, HER2-negative breast cancer. Given that chemotherapy is an option with unreliable outcomes for this subtype, this nomogram may be used to select patients for NAC followed by successful BCS.

• Fire Science and Engineering
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• v.33 no.6
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• pp.35-42
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• 2019

The aim of this study is to investigate the direction of improvement of safety experience education through the analysis of the evacuation time experiment. For the study, test subjects were divided into groups of similar body size and weight. The test subjects were directly experienced four evacuation devices, and the experience time was measured. As a result of the analysis of the total time from the installation of the evacuation device to the escape, the time was measured in the order of Descending Life Line-Tilt-Down Rescue Line-Vertical Escape Chute-air safety mat. In the case of evaluating the evacuation time using evacuation mechanisms, the evacuation time was measured in the order of air safety mat-Tilt-Tilt-Down Rescue Line-Descending Life Line-Vertical Escape Chute. In the first and second experiments of the Descending Life Line, time differences were observed. The escape time using the Descending Life Line was reduced in the second experiment than in the first experiment. As shown in this result, education through experience has shown that behavioral confidence and time can be managed. The conclusion of this study is that the goal of safety education is to minimize human life and property damage. Therefore, in order to bring this effect to more people, it is necessary to make efforts to keep self-safe through experiential education.

• Progress in Medical Physics
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• v.27 no.4
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• pp.241-249
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• 2016

The present study used a digital angiography x-ray device to measure the space dose and exposure dose of patients and practitioners using x-ray tube shielding devices developed in our laboratory. The intent of the study was to reduce the space dose within the test room, and to reduce the exposure dose of patients and practitioners. The patient and practitioner exposure doses were measured in five configurations in a human body model. The glass dosimeter was placed on the eye lenses, thyroid glands, left shoulder, right shoulder, and gonads. The beam was collimated at full size and at a 48% reduction for a comparative analysis of the measurements. The space dose was measured with an ion chamber at distances of 50 cm, 100 cm, and 150 cm from the x-ray tube under the following conditions: no shielding device; a shielding device made of 3-mm-thick lead (Pb) [Pb 3 mm shield], and a shielding device made of 3-mm-thick Pb (outside) and 3-mm-thick aluminum (Al) (inside) [Pb 3 mm＋Al 3 mm shield]. The absorbed dose was the lowest when the 3-mm-thick Pb＋3-mm-thick Al shield was used. For measurements made with collimated beams with a 48% reduction, the dose was the lowest at $154{\mu}Gy$ when the 3-mm-thick Pb＋3-mm-thick Al shield was used, and was $9{\mu}Gy$ lower than the measurements made with no shielding device. If the space dose can be reduced by 20% in all situations where the C-arm is employed by using the x-ray tube shielding devices developed in our laboratory, this is expected to play an important role in reducing the annual exposure dose for patients, practitioners, and assistants.

• Clean Technology
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• v.28 no.2
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• pp.123-130
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• 2022

Nanoparticles are used in various fields such as chemistry, medicine, the environment, and information and communication. With the increasing use of engineered nanomaterials, exposure to nanoparticles is expected to increase in the workplace and the environmental media. However, while nanotechnology industries are expanding, research on the exposure assessment of nanomaterials to humans and the environment is only at a beginning stage. Especially, if nanoparticles with a size of 100 nm or less that are contained in nano-products are released unintentionally, they may pose potential risks to the human body through breathing or skin exposure. Therefore, in this work, the possibility of potential exposure of nanoparticles moving from the laboratory to the office was confirmed, and nanoparticle safety guidelines are proposed. A nano-collector was used to detect nanoparticles in the atmosphere, and through use of a scanning mobility particle sizer it was found that nanoparticle concentrations in the laboratory and the office tended to be similar. On the assumption that nanoparticles attached to a lab-coat move out of the laboratory, a lab-coat to which nanocarbon black was attached was shaken and the concentration of the remaining particles on the lab-coat determined. The results confirmed that sufficient amounts of nanoparticles attached to the lab-coat could move from the laboratory to the office along the path of a researcher; thus, safety guidelines for the handling of lab-coat nanoparticles are required.

• Journal of Environmental Health Sciences
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• v.37 no.6
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• pp.440-449
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• 2011

Objectives: This study was designed to determine the levels of polybrominated diphenyl ethers (PBDEs) in breast milk and to evaluate the relations with factors affecting these levels. Methods: The congener levels of PBDE in 22 samples of breast milk were analyzed using a high resolution gas chromatograph with a high resolution mass detector. In accordance with our standard operating procedures, the recoveries of internal standards had to range between 68% and 118%. Since the distribution of PBDE concentrations is close to log-normal, the data were logarithmically transformed before analysis. Test subjects were healthy primipara and multipara mothers with a mean age of 32 (SD = 2.7) in 2006. Results: Seven PBDE congeners (BDE-28, 47, 99, 100, 153, 154, and 183) were detected and identified in all of the pooled breast milk samples, indicating widespread contamination from PBDEs in the environment in Korea. Residue levels of total PBDEs (sum PBDEs from tri- to hepta-BDE) ranged from 0.84-13.1 ng/g lipid with median and geometric mean levels of 2.6 ng/g lipid and 2.74 ng/g lipid, respectively. PBDE congeners 47, 99 and 153 markedly predominated and accounted for about 75% of the amount of the PBDE congeners analyzed. BDE-47 was the dominant congener in most samples, whereas BDE-153 was predominant in a few (n = 7/22). BDE-47 was highly correlated with total PBDEs (r = 0.987, p < 0.01). In analyses of the differences of the means of log transformed breast milk PBDE levels for groups of potential covariates, only breast milk BDE-47 and BDE-99 levels were significantly associated with fish (p < 0.05) and meat consumption (p < 0.01). However, we did not find significant correlations between PBDE levels and maternal age, body mass index (BMI), parity, job presence and smoking status. Conclusions: Our findings are mainly limited due to the small sampling size and low doses of PBDEs exposure. Background and human exposure data of PBDEs is lacking, and longitudinal investigations into the environment and biota are encouraged to determine the health impact on future populations in Korea.