• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.11 no.7
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• pp.287-294
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• 2001

The identification of connection stiffnesses of bolted structures is presented using FRT-based substructural sensitivity analysis. The substructural design sensitivity formula is derived and plugged into the optimization module of MATLAB to identify connection stiffnesses of an air-conditioner compressor or passenger Car. The air-conditioner composed of a compressor and a bracket, is analysed by using the FRT-based substructural(FBS) method to obtain FTRs an FE model is generated for the bracket, and the impact hammer test is performed for the compressor, Obtained FRTs are combined to calculate the reaction force at the connection point and the system response. By minimizing the difference between a target FRT and calculated one the connection element properties of the air-conditioner syste are identified It is shown that the proposed identification method is effective for a real problem.

• Journal of Animal Science and Technology
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• v.55 no.5
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• pp.427-434
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• 2013

This study was conducted to establish methods for preserving chicken primordial germ cells (PGCs) for long-term storage in liquid nitrogen and for developmental engineering or preservation of species. The purpose of this study is to clarify the effects of fetal bovine serum (FBS) or chicken serum (CS) treatment on the viability of cryopreserved PGCs from Korean Native Chicken (Ogye). PGCs separated from a germinal gonad of an early embryo at day 5.5-6 (stage 28) were suspended in a freezing medium containing freezing and protective agents (dimethyl sulfoxide (DMSO), ethylene glycol (EG) and glycerol). The values from 0, 5, 10, and 15 % DMSO plus FBS treatment were 21.6, 30.36, 36.42, 50.39, and 48.36 %, respectively. The viability of PGCs after freeze-thawing was significantly higher for 10% EG plus FBS treatment than for 10% EG + FCS treatment (p<0.05) (64.36% vs. 50.66%). This study establishes a method for preserving chicken PGC that enables systematic storage and labeling of cryopreserved PGC in liquid nitrogen at a germplasm repository and an ease of entry into a database. In the future, the importance for this new technology is that poultry lines can be conserved while work is being conducted to improve the production of germline chimeras.

• Journal of the Korean Society of School Health
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• v.17 no.1
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• pp.71-83
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• 2004

Purpose: To describe the prevalence, epidemiological characteristics, and related factors of diabetes mellitus in school personnel. Method：5,384 school personnel (2,638 males 2,746 females) received physical examinations at the Seoul School Health Center in 2002. Using the American Diabetes Association criteria, and fasting blood sugar(FBS) was classified as normal at 110>=FBS, borderline 111-125, and the diabetes group 126<=FBS. Related factors of each group were evaluated by gender. Results： In the diabetes group, there were 4.74% males and 0.8% females, and the borderline group was 6.37% males and 2.22% females. The older age group gad a higher distribution in both males and females in the diabetes group. In the diabetes group, the mean and abnormal rate of BMI, systolic hypertension, diastolic hypertension, total cholesterol, GOT, GPT, and GTP were higher than in the normal group. In life style factor, the diabetes group gad a higher distribution of meat eating and smoking more than 20 years than the normal group. The effect of FBS on BMI, BP(blood pressure), total cholesterol, GOT, GPT, and GTP were investigated after controlling for confounding variables. In the borderline and diabetes group, the mean of BMI, BP, total cholesterol, GOT, GPT, and GTP was higher in dose-response effect. In the logistic multiple regression, the related factors of the diabetes group were hypertension and abnormal GTP in males, and abnormal total cholesterol and GTP in females. In the borderline group, the related factors were meat eating, hypertension, and high GOT in males and the older age group, and hypertension, total cholesterol, and abnormal GTP in females. Conclusions: It is possible to manage all related factors of diabetes mellitus except for age. An appropriate program for health promotion is necessary.

• Journal of Embryo Transfer
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• v.24 no.4
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• pp.281-287
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• 2009

As a simple and economical method for in vitro produced embryos, we have used BSA instead of serum for the production and embryo transfer of Hanwoo in vitro fertilized (IVF) embryos and obtained the following results: 1) When using serum (FBS; fetal bovine serum) or BSA-containing culture media as the initial culture media for immature oocytes, it is regarded as inappropriate to add only BSA to the culture solutions from maturation of the immature oocytes to development stage culture, but serum still needs be added though there is no significant difference in the concentration, with a change from 5% to 10%. 2) The results of culturing IVF embryos after development (4 cell stage) in the Medium199 solutions containing BSA instead of serum (FBS) showed that 0.3% BSA concentration is not optimal and 0.5% or higher BSA concentration has no significant difference among 0.5%, 0.7%, 1% and 2% (p > 0.05). 3) The post-freezing survival ratio after development in 5% FBS-Medium199 showed that 1% BSA concentration of the culture solution is the most suitable in the BSA concentrations of 0.3% (51%), 0.5% (67%), 0.7% (69%), 1% (77%) and 2% (75%). 4) The pregnancy rates of the transplanted fresh(not frozen) blastocyst had no significant concentration dependency (p > 0.5), and the average pregnancy rate was 63.8%. 14% of overweight calves were found among the calves given birth to by the transfer of IVF blastocysts cultured in the serum-added culture solution, but none was found in the experimental groups in which BSA was added instead of serum.

• Journal of Animal Reproduction and Biotechnology
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• v.38 no.3
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• pp.143-150
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• 2023

Background: The successful production of superior or transgenic offspring from in vitro produced embryos in cattle relies heavily on the quality of blastocyst stage embryos. In order to enhance the developmental competency of these embryos, a novel culture method was devised. Methods: This study utilized stem cell culture medium (SCM) from hESCs as a supplement within the culture medium for bovine in vitro produced embryos. To gauge the efficacy of this approach, in vitro fertilized embryos were subjected to culture in CR1aa medium enriched with one of three supplements: 0.3% BSA, 10% FBS, or 10% SCM. Results: The blastocyst development and hatching rates of one-cell zygotes cultured in CR1aa medium supplemented with SCM (23.9% and 10.2%) surpassed those cultured in CR1aa medium supplemented with BSA (9.3% and 0.0%) or FBS (3.1% and 0.0%) (p < 0.05). Furthermore, post-zygotic gene activation, cleaved embryos cultured in CR1aa medium supplemented with SCM (57.8% and 34.5%) exhibited notably higher rates (p < 0.05) compared to those cultured with BSA (12.9% and 0.0%) or FBS (45.7% and 22.5%) supplementation. Furthermore, the microinjection of SCM into the cytoplasm or pronucleus of fertilized zygotes resulted in elevated blastocyst development and hatching rates, particularly when the microinjected embryos were subsequently cultured in CR1aa medium supplemented with SCM from the 8-cell embryo stage onwards (p < 0.05), in contrast to those cultured with FBS supplementation. Conclusions: In conclusion, this study conclusively demonstrated that the incorporation of SCM into the culture medium significantly enhances the developmental progress of preimplantation embryos.

• Journal of Biomedical Engineering Research
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• v.16 no.4
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• pp.463-470
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• 1995

Complete prelining of artificial vascular grafts with autologous endothelial cells may be one of the ideal solutions to obtain a nonthrombogenlc blood-contacting surface. To establish an intact endothelial cell monolayer on a prosthetic surface at the time of implantation,a sufficient number of endothelial cells and adequate propagation condition In cell culture are prerequisites. In this experimental study, endothelial cells from microvessels of adult human oriental adipose tissue were enzymatically harvested, and optimal culture conditions for proliferation of the endothelial cells in cell culture were examined. Human oriental adipose tissue was digested with collagenase and endothelial cells were separated from other stromal elements by mesh filtration method. Cultured cells were identified as endothelial cells by immunofluorescent staining for factor VIII-related antigen. Proliferation in usual 20% fetal bovine serum (FBS) medium or medium containing endothelial cell growth factor (ECGF)(5 ng/ml) and heparin (HEP)(1,000 units/ml) were compared,and the effects of adding compounds that increase intracellular cyclic adenosine monophosphate levels, that is,cholera toxin (CT)(1 $\mu\textrm{g}$/ml) and isobutylmethylxanthine (IBMX)(0.2 ml),were also analyzed. In total,following eight media groups were examined. 1) FBS medium + ECGF + HEP, 2) FBS medium + ECGF + HEP+CT, 3) FBS medium+ECGF+HEP+lBMX, 4) FBS medium+ECGF+HEP+CT+ IBMX, 5) FBSmedium, 6) FBS medium +CT, 7) FBS medium + IBMX, 8) FBS medium + CT + IBMX. It was shown that the medium containing ECGF + HEP with or without cholera toxin was most efficient in Stimulating cell proliferation. IBMX was considered to have antagonistic effect to ECGF. Among experimental groups without ECGF and HEP, the addition of cholera toxin and IBMX was shown to significantly potentiate cell proliferation. This results could provide a practical method for use of cultured human endothelial cells for endothelial cell seeding of cardiovascular prosthetic device, particularly in small-diameter vascular grafts.

• Reproductive and Developmental Biology
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• v.36 no.1
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• pp.65-70
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• 2012

For reconstituting genetic resource(Korean Native Chicken: KNC) with grem-line chimeric chicken made with cryopreserved biastdermal cells, the experiments were carried out to optimize cryopreservating conditions. Stage X biastdemal cells were collected from KNC embryos and dissociated. Cells were susupended in medium containing cyopretectant and fetal bovine serum(FBS), and distributed into plastic ampules. Cell susupensions were seeded to induce ice formation at $-7^{\circ}C$ to $-35^{\circ}C$ at in the experiments, the effect of modification of dissociation way, concentration of FBS and cell density on the vaibility of frezen-thawed cells were investigated by trypan blue exclusion. Then change the way of cell dissociation from pipetting to short time vortexing, viability of frozen-thawed cell tended to be increaced from 29 % to 52 %. Increase concentraition of FBS in frozen medium from 20 % to 80 % made viability of thawed cell from 28 % to 35 %. The viability of thawed cells were 33.9% frozen at 2 embryos/0.5 ml, and 43.6 % frozen at 20 embryos/0.5 ml. Furthermore, combination of three modifications make big improvement. The viability of frozen-thawed cell was 60 % for combinated method, and 41 % for general method. This result means the advance to practical cryoreservation of blastdermal cell of the KNC(Ogolgye breed).

• Clinical and Experimental Reproductive Medicine
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• v.27 no.1
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• pp.23-29
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• 2000

Objective: Zona pellucida (ZP) has been thought to be the barrier of egg to sperm penetration before and after fertilization. The phenomenon of ZP hardening has been considered as a post-fertilization event until now, and it is generally accepted that it is caused by the secretory products of cortical granules released during the cortical reaction. Hardening of ZP could occur "spontaneously" in mammalian oocytes in standard culture conditions, and that it is probably not a consequence of cortical reaction. The purpose of our study was to investigate the effect of human amniotic fluid (HAF) on nuclear maturation (NM) and fertilization ability of mouse immature oocytes. Methods: HAF was obtained from patients undergoing amniocentesis at $16{\sim}20$ weeks of gestation. HAF from five to ten patients was centrifuged and the supernatants was pooled. Cumulusenclosed mouse immature oocytes were incubated in the medium containing HAF, and examined to confirm NM and fertilization. Female ICR mice (about 3 weeks old) were stimulated with 7.5 IU PMSG. Immature oocytes were isolated at $48{\sim}52$ hrs post PMSG injection and cultured in TCM-199 supplemented with 20% HAF for 18 hrs. FBS was used as a control for the examination. Matured oocytes (MII) were fertilized with sperms collected from the epididymis of male mice (over 10 weeks old). Fertilization was in conducted T6 medium containing 15 mg/ml BSA, and confirmed at 6 hrs post-insemination. Fertilization rate was assessed in zona-intact or zona-free oocytes (denuded by trypsin). Evaluation of NM and fertilization was carried out by rapid staining method. ZP hardening was evaluated by incubating cumulus cell-free mature oocytes in 0.001% chymotrypsin at $37^{\circ}C$ for 10 min. Results: There was no significant difference between the effects of HAF (86.6%) and FBS (87.7%) supplements on NM of immature oocytes. When maturation medium was supplemented with HAF, total fertilization rates (7%) were significantly lower (p<0.01) than that of FBS (85.1%). In HAF group, fertilization rate was increased (p<0.01) in zona-free oocytes (7% versus 100%). The resistance of mouse oocyte ZP to digestion by chymotrypsin after maturation in vitro was significantly higher (p<0.01) in HAF group (86.7%) than in FBS (6.7%). To culture oocytes in FBS were very effective in preventing ZP hardening. However cultured oocytes in HAF showed high rate of ZP hardening (p<0.01). Conclusions: These results suggest that HAF can be used as a supplement for the NM of mouse immature oocytes in vitro. However, HAF induces spontaneous hardening of ZP of mouse immaure oocytes during maturation in vitro.

• Journal of Microbiology and Biotechnology
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• v.12 no.6
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• pp.882-889
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• 2002

Hantaan vims production, using human immortalized retina cell (PER. C6), was investigated to develop an inactivated virus vaccine. To infect Hantaan virus into PER. C6, two infection methods (medium-to-cell and cell-to-cell) were tried, and IFA results showed that the cell-to-cell infection method was very useful for producing Hantaan virus-infected PER, C6. Hantaan virus production was significantly affected by the growth rate of PER. C6 and the content of FBS in medium. Higher specific growth rate of infected PER. C6 and lower FBS content induced higher production of Hantaan virus. The inactivated human cell-culture vaccines with various EIA titers were prepared, their antibody responses were compared with those of inactivated suckling mouse brain vaccines ($Hantavax^처리불가$). and the result showed their immunogenicities were slightly higher than those of inactivated suckling mouse vaccines. Therefore, this study shows the possibility of the development of Hantaan virus vaccine from a human cell culture.

• Journal of Biomedical Engineering Research
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• v.22 no.4
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• pp.369-375
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• 2001

The statistical regression model is one of the most frequently used clinical analysis methods. It has basic assumption of linearity, additivity and normal distribution of data. However, most of biological data in medical field are nonlinear and unevenly distributed. To overcome the discrepancy between the basic assumption of statistical model and actual biological data, we propose a new analytical method based on artificial neural network. The newly developed multilayer perceptron(MLP) is trained with 120 data set (60 normal, 60 patient). On applying test data, it shows the discrimination power of 0.76. The diabetic risk factors were also identified from the MLP neural network model and the logistic regression model. The signigicant risk factors identified by MLP model were post prandial glucose level(PP2), sex(male), fasting blood sugar(FBS) level, age, SBP, AC and WHR. Those from the regression model are sex(male), PP2, age and FBS. The combined risk factors can be identified using the MLP model. Those are total cholesterol and body weight, which is consistent with the result of other clinical studies. From this experiment we have learned that MLP can be applied to the combined risk factor analysis of biological data which can not be provided by the conventional statistical method.