• Communications for Statistical Applications and Methods
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• v.6 no.3
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• pp.957-966
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• 1999

We evaluate the accuacy and precision of maximum likelihood estimation procedures for infectivity of HIV in partner studies. This is achieved by applying the oricedyre typothetical samples generated by computer. One hundred samples were generated with various combinations of parameters. The estimation procedure was found to be quite accurate. in addition it was found that the power of the test for equality of infectivities for two types of contact depends on sample size and length of observation period but not on the number of observations made on each subject. Tests based on a model for the infectivity had higher power than standard methods for comparing proportions.

• The Journal of Korean Society for School & Community Health Education
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• v.9 no.1
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• pp.63-83
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• 2008

Objectives: This study was to examine HIV/AIDS knowledge of transmission, attitudes toward homosexuals on stigma of HIV/AIDS and discriminatory attitudes towards person with HIV/AIDS (PWHAs) by middle and high school students in Seoul, Korea. Methods: The population of this study is middle and high school students in Seoul, Korea. Eight junior high schools and eight senior high schools were selected randomly. Three thousand and one hundred thirty-one students (1704 males and 1397 males) from 16 schools participated in the survey, and 2.977 cases were analyzed. A self-administered questionnaire measuring socio-demographic variables, HIV/AIDS knowledge of transmission, sigma of HIV/AIDS (3 items, 5-point Likert-type scale) and discriminatory attitudes PWHAs (5 items, 5-point Likert-type scale) was utilized. The Structural Equation Modeling was employed to investigate the research Model. Results: The empirical study shows that a number of statistical hypotheses are significant. The stigma and discriminatory attitudes PWHAs were significantly different by middle and high school students. The attitudes toward homosexuals and HIV/AIDS knowledge of transmission were important factors on stigma and discriminatory attitudes PWHAs. Socio-demographical variables such as sex was related to the stigma and discriminatory attitudes PWHAs. Conclusion: Therefore, it is important to design HIV prevention strategies that increase in positive attitudes towards PWHAs.

• Korean Journal of Veterinary Research
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• v.40 no.3
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• pp.471-478
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• 2000

The pharmacokinetic properties of KR-V compounds, recently developed as new anti-HIV agents, were studied after i.v. and p.o. administration in rats. The concentrations of the KR-V series were determined in rat plasma using an high-performance liquid chromatography (HPLC)-UV detection system. Of the 19 KR-V compounds investigated in the present study, only KR-V 3, 10, 14, 16 and 18-1 showed oral bioavailability. The plasma concentration-time data could be adequately described by an one-compartment open model. In the i.v. kinetic study (10mg/kg), the CLt of KR-V 3, 10, 14 and 16 (>4L/hr/kg) were significantly higher than that of KR-V 18-1 (1.1 L/hr/kg). The AUC of KR-V 18-1 was greater ($8.97{\mu}g{\cdot}hr/ml$) than that of the other compounds, but the Vd (0.58 L/kg) was lower. In the p.o. kinetic study (50mg/kg), although the t-1/2 of KR-V 18-1 was shorter than that of the other compounds, the AUC ($3.659{\mu}g{\cdot}hr/ml)$ and $C_{max}(1.891{\mu}g/ml$) were markedly higher. In a seperated in vitro experiment, only KR-V 18-1, of the 5 compounds with bioavailibility, exhibits potent activity against HIV-1 mutant strains. Therefore, KR-V 18-1 is expected to become a new potent anti-AIDS drug candidate/lead compound.

• Korean Journal of Microbiology
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• v.45 no.4
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• pp.346-353
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• 2009

Viral, bacterial, and fungal infection can be transmitted from donor to recipient via transplantation of human amniotic membrane. Therefore human amniotic membrane for transplantation should be disinfected and sterilized before use. The purpose of this study was to examine the efficacy of the disinfection process and sterilization processes used at human tissue bank in the inactivation of viruses, bacteria, and fungi. A variety of experimental model viruses, bacteria, and fungus for human pathogens, including the human immunodeficiency virus type 1 (HIV-1), bovine herpes virus (BHV), bovine viral diarrhoea virus (BVDV), hepatitis A virus (HAV), porcine parvovirus (PPV), Escherichia coli, Bacillus subtilis, and Candida albicans were all selected for this study. Enveloped viruses such as HIV-1, BHV, and BVDV were effectively inactivated to undetectable levels by 70% ethanol treatment, gamma irradiation process, and ethylene oxide (EO) gas sterilization process. Also non-enveloped viruses such as HAV and PPV were effectively inactivated to undetectable levels by gamma irradiation and EO gas treatment. However HAV and PPV showed high resistance to 70% ethanol treatment. E. coli and C. albicans were effectively inactivated to undetectable levels by 70% ethanol treatment, gamma irradiation process, and EO gas treatment. Also B. subtilis was effectively inactivated to undetectable levels by gamma irradiation process and EO gas treatment. However it showed high resistance to 70% ethanol treatment.

• Microbiology and Biotechnology Letters
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• v.38 no.2
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• pp.168-176
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• 2010

Acellular dermal matrix (ADM), produced by decellularization from human cadaveric skin, has been used for various biomedical applications. A manufacturing process for ADM ($SureDerm^{TM}$) using tri-n-butyl phospahate (TnBP) and deoxycholic acids as the decellularization solution has been developed. The manufacturing process for $SureDerm^{TM}$ has 70% ethanol treatment and ethylene oxide gas sterilization for inactivating infectious microorganisms. The purpose of this study was to examine the efficacy of the 70% ethanol treatment, decellularization process using 0.1% TnBP and 2% deoxycholic acids, and EO gas sterilization process in the inactivation of viruses. A variety of experimental model viruses for human pathogens, including the human immunodeficiency virus type 1 (HIV-1), bovine herpes virus (BHV), bovine viral diarrhoea virus (BVDV), hepatitis A virus (HAV), and porcine parvovirus (PPV) were all selected for this study. Enveloped viruses such as HIV-1, BHV, and BVDV were effectively inactivated to undetectable levels by 70% ethanol treatment. However HAV and PPV showed high resistance to 70% ethanol treatment with the log reduction factors of 1.85 and 1.15, respectively. HIV-1, BHV, and BVDV were effectively inactivated to undetectable levels by decellularization process. All the viruses tested were completely inactivated to undetectable levels by EO gas treatment. The cumulative log reduction factors of HIV-1, BHV, BVDV, HAV, and PPV were $\geq12.71$, $\geq18.08$, $\geq14.92$, $\geq6.57$, and $\geq7.18$, respectively. These results indicate that the production process for $SureDerm^{TM}$ has a sufficient virus-reducing capacity to achieve a high margin of the virus safety.

• Korean Journal of Health Education and Promotion
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• v.14 no.2
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• pp.125-147
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• 1997

This study was conducted in order to identify the extent to which Health Belief Model (HBM) constructs explain the likelihood of taking preventive behaviors for AIDS among the young adolescents in Korea. HBM was applied as the theoretical framework for developing questionnaire items in this study. The survey instrument included all of the constructs of Health Belief Model, namely, perceived susceptibility, perceived severity, perceived benefit, perceived barriers, cue to actions for preventive behaviors concerning AIDS. Additionally, demographic characteristics of the respondents, their sexual experiences, and AIDS Knowledge Test were included in the study. Each of HBM constructs were developed with a 5-point Likert type scale from l(never agree) to 5 (absolutely agree). The survey was conducted with a total of 247 military men in a city on September 18, 1996, using self-reported questionnaire. The results of the study were summarized as follows: 1. Because the subjects for this study were military soldiers, their demographic characteristics were limited to all men, young age, and ummarried. Educational status was evenly distributed between high school graduates and university students. 2. On the average, the respondents started their first sexual relationship at 18 years old and 82.6% of them did not use condom when having their first sexual experience. Thirty-one percent of the subjects had sexual contact with prostitutes and the average number of sexual contact with prostitutes was 5 times during the past 2 years. 3. The results of AIDS Knowledge Test scores demonstrated that the respondents had a high level of knowledge about AIDS. However, some misconceptions about transmission of AIDS through casual contact were still prevailed. Sixty-six percent of the respondents expressed that people infected with HIV should be isolated from the society in order to protect the general public. 4. All the respondents expressed that they had heard about AIDS before. TV was found to be the source which provided information on AIDS most frequently. 5. Among fundamental constructs of Health Belief Model, scores of perceived benefit of taking preventive action against AIDS marked the highest score, while scores of perceived susceptibility were the lowest. As a result of Multiple Stepwise Regression analysis, 13 variable groups were found to predict the preventive action by 25%. Among them, only perceived benefit variables was the most significant factor to explain preventive behaviors by 17%.

• Journal of Microbiology and Biotechnology
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• v.18 no.7
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• pp.1317-1325
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• 2008

Viral safety is an important prerequisite for clinical preparations of plasma-derived pharmaceuticals. One potential way to increase the safety of therapeutic biological products is the use of a virus-retentive filter. In order to increase the viral safety of human antihemophilic factor IX, particularly in regard to non-enveloped viruses, a virus removal process using a polyvinylidene fluoride membrane filter (Viresolve NFP) has been optimized. The most critical factor affecting the filtration efficiency was operating pH and the optimum pH was 6 or 7. Flow rate increased with increasing operating pressure and temperature. Recovery yield in the optimized production-scale process was 96%. No substantial changes were observed in the physical and biochemical characteristics of the filtered factor IX in comparison with those before filtration. A 47-mm disk membrane filter was used to simulate the process performance of the production-scale cartridges and to test if it could remove several experimental model viruses for human pathogenic viruses, including human hepatitis A virus (HAV), porcine parvovirus (PPV), murine encephalomyocarditis virus (EMCV), human immunodeficiency virus type 1 (HIV), bovine viral diarrhea virus (BVDV), and bovine herpes virus (BHV). Non-enveloped viruses (HAV, PPV, and EMCV) as well as enveloped viruses (HIV, BVDV, and BHV) were completely removed during filtration. The log reduction factors achieved were $\geq$6.12 for HAV, $\geq$4.28 for PPV, $\geq$5.33 for EMCV, $\geq$5.51 for HIV, $\geq$5.17 for BVDV, and $\geq$5.75 for BHV. These results indicate that the virus filtration process successfully improved the viral safety of factor IX.

• The Korean Journal of Applied Statistics
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• v.30 no.2
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• pp.233-241
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• 2017

Interval censored data frequently occur in observation studies where the subject is followed periodically. In this paper, our interest is to suggest a test statistic to compare the CIF of two groups with interval censored failure time data in the presence of competing risks. Gray (1988) suggested a test statistic for right censored data that motivated a well-known Fine and Gray's subdistribution hazard model. A multiple imputation technique is adopted to adopt Gray's test statistic to interval censored data. The powers and sizes of the suggested method are investigated through diverse simulation schemes. The main merit of the suggested method is its simplicity to implement with existing software for right censored data. The method is illustrated by analyzing Bangkok's HIV cohort dataset.

• Proceedings of the Korean Association for Survey Research Conference
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• 2006.06a
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• pp.131-159
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• 2006

This paper consider multinomial group testing which is concerned with classification each of N given units into one of k disjoint categories. In this paper, we propose exact Bayesian, approximate Bayesian, bootstrap methods for estimating individual category proportions using the multinomial group testing model proposed by Bar-Lev et al (2005). By the comparison of Mcan Squre Error (MSE), it is shown that the exact Bayesian method has a bettor efficiency and consistency than maximum likelihood method. We suggest an approximate Bayesian approach using Markov Chain Monte Carlo (MCMC) for posterior computation. We derive exact credible intervals based on the exact Bayesian estimators and present confidence intervals using the bootstrap and MCMC. These intervals arc shown to often have better coverage properties and similar mean lengths to maximum likelihood method already available. Furthermore the proposed models are illustrated using data from a HIV blooding test study throughout California, 2000.

• Proceedings of the Korean Society for Bioinformatics Conference
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• 2005.09a
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• pp.272-277
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• 2005

We introduce a new approach to optimize the parameters in biological kinetic models by quantifier elimination (QE), in combination with numerical simulation methods. The optimization method was applied to a model for the inhibition kinetics of HIV proteinase with ten parameters and nine variables, and attained the goodness of fit to 300 points of observed data with the same magnitude as that obtained by the previous optimization methods, remarkably by using only one or two points of data. Furthermore, the utilization of QE demonstrated the feasibility of the present method for elucidating the behavior of the parameters in the analyzed model. The present symbolic-numeric method is therefore a powerful approach to reveal the fundamental mechanisms of kinetic models, in addition to being a computational engine.