• Analytical Science and Technology
• /
• v.17 no.3
• /
• pp.211-216
• /
• 2004

Commercial one-step rapid fecal occult blood (FOB) kit which was used as a screening test to detect traces of blood in stool samples was evaluated for the feasibility of the forensic identification of human blood. The sensitivity was determined and compared with the conventional Leucomalichite green (LMG) method. In addition, the specificity of the kit and the effects of various chemicals and environmental factors were examined. FOB kit was specific for human hemoglobin and more sensitive than LMG test (approximately 100 times). FOB kit showed positive band using at least 1,000,000-fold diluted human blood. The antigen was very stable regardless of storage temperature and boiling. The positive reaction was not affected by LMG and Luminol, the traditional tests for identification of bloodstain. As a results, FOB test kit could be effectively applied to identification of human blood at crime scene and crime laboratories.

• Applied Chemistry for Engineering
• /
• v.28 no.1
• /
• pp.35-41
• /
• 2017

Materials exposed to outside will deteriorate due to various weathering factors such as sunlight, heat, temperature, humidity and so on. Therefore, predicting speed of degradation and life time is a very important issue. This research uses retro-reflective sheets with white and green which are most commonly used colors to conduct the outdoor exposure test and acceleration test of xenon arc in Arizona state in the United States, Chennai in India, Sanary in France and Seosan in Korea to measure the reflective performance of retro-reflection. The accelerated factor was obtained by using regression analysis through reflective values obtained from the acceleration test of xenon arc from Seosan area. Also, by using solar uv program, the accelerated factor of various climate regions were obtained and it was confirmed that the accelerated factor of Senary was 1.04, Arizona 1.82, Chennai 1.92 times higher than that of Seosan.

• Korean Chemical Engineering Research
• /
• v.50 no.3
• /
• pp.421-426
• /
• 2012

The effect of synthesis conditions such as various organic material and composition of organic-inorganic material in ozone resistance and surface characteristic of ultraviolet cured organic-inorganic hybrid coating film has been investigated. Organic-inorganic hybrid coating solution was prepared using tetraethoxysilane (TEOS), silane coupling agent methacryloyloxypropyltrimethoxysilane (MPTMS), 2,2,2-trifluoroethylmethacrylate, and various organic materials with acrylate group, bar-coated on substrates using applicator and densified by UV-curing. It was found that ozone resistance and surface hardness of the coating film was increased with contents of TEOS. It was also found that ozone resistance of coating film was increased with contents of 2,2,2-trifluoroethylmethacrylate. On the other hand, surface hardness was decreased with increase of 2,2,2-trifluoroethylmethacrylate. In addition, Surface hardness of coating film was increased with the addition of aliphatic urethane acrylate. It was also found that the transmittance of coating films was not influenced by content of TEOS and 2,2,2-trifluoroethylmethacrylate. In addition, the coating film exhibited high transmittance of above 90%.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.19 no.2
• /
• pp.46-54
• /
• 2015

Nitrous oxide is known as green and safe propellant, and can be supplied by its own vapor pressure. So, many liquid propulsion research institutes and university laboratories use nitrous oxide as oxidizer of experimental liquid rocket engine. However, the unknown explosions occurred twice during hot fire experiments using subscale ethanol/nitrous oxide thruster. In this paper, we surmised that the explosions were caused by the decomposition of nitrous oxide in the injector body and the recondensation of nitrous oxide. Improvement and the safe handling methods are suggested.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.28 no.3
• /
• pp.241-256
• /
• 2018

Objectives: This study aimed to review the characteristics of three-dimensional printing technology focusing on printing types, materials, and health hazards. We discussed the methodologies for exposure assessment on hazardous substances emitted from 3D printing through article reviews. Methods: Previous researches on 3D printing technology and exposure assessment were collected through a literature review of public reports and research articles reported up to July 2018. We mainly focused on introducing the technologies, printing materials, hazardous emissions during 3D printing, and the methodologies for evaluation. Results: 3D printing technologies can be categorized by laminating type. Fused deposition modeling(FDM) is the most widely used, and most studies have conducted exposure assessment using this type. The printing materials involved were diverse, including plastic polymer, metal, resin, and more. In the FDM types, the most commonly used material was polymers, such as acrylonitrile-butadiene-styrene(ABS) and polylactic acids(PLA). These materials are operated under high-temperature conditions, so high levels of ultrafine particles(mainly nanoparticle size) and chemical compounds such as organic compounds, aldehydes, and toxic gases were identified as being emitted during 3D printing. Conclusions: Personal desktop 3D printers are widely used and expected to be constantly distributed in the future. In particular, hazardous emissions, including nano sized particles and various thermal byproducts, can be released under operation at high temperatures, so it is important to identify the health effects by emissions from 3D printing. Furthermore, appropriate control strategies should be also considered for 3D printing technology.

• Journal of Environmental Health Sciences
• /
• v.44 no.6
• /
• pp.524-538
• /
• 2018

Objective: This study aimed to identify the size distributions of particulate matter emitted during 3D printing according to operational conditions and estimate particle inhalation exposure doses at each respiratory region. Methods: Four types of printing filaments were selected: acrylonitrile-butadiene-styrene (ABS), polylactic acid (PLA), Laywood, and nylon. A fused deposition modeling (FDM) 3D printer was used for printing. Airborne particles between 10 nm and $10{\mu}m$ were measured before, during, and after printing using real-time monitors under extruder temperatures from 215 to $290^{\circ}C$. Inhalation exposures, including inhaled and deposited doses at the respiratory regions, were estimated using a mathematical model. Results: Nanoparticles dominated among the particles emitted during printing, and more particles were emitted with higher temperatures for all materials. Under all temperature conditions, the Laywood emitted the highest particle concentration, followed by ABS, PLA, and nylon. The particle concentration peaked for the initial 10 to 20 minutes after starting operations and gradually decreased with elapsed time. Nanoparticles accounted for a large proportion of the total inhaled particles in terms of number, and about a half of the inhaled nanoparticles were estimated to be deposited in the alveolar region. In the case of the mass of inhaled and deposited dose, particles between 0.1 and $1.0{\mu}m$ made up a large proportion. Conclusion: The number of consumers using 3D printers is expected to expand, but hazardous emissions such as thermal byproducts from 3D printing are still unclear. Further studies should be conducted and appropriate control strategies considered in order to minimize human exposure.

• Journal of Genetic Medicine
• /
• v.18 no.1
• /
• pp.38-43
• /
• 2021

Purpose: Demand for genetic counseling on cancer predisposition syndrome is increasing. We evaluated the psychological effect on counselees after genetic counseling at a clinic in a single center. Materials and Methods: We surveyed a total of 72 enrolled participants who visited a genetic counseling clinic at the Samsung Medical Center (SMC). The initial survey was conducted before the first genetic counseling session, and the second survey was conducted after the second genetic counseling session. A total of 43 participants completed both the initial and second surveys. Results: The initial survey of 72 participants indicated higher feelings of guilt in the group with religion, higher depression and anxiety in the group with a diagnosis of self, and higher anxiety in the group on self-referral to the genetic counseling clinic. In the completed survey of 43 participants, overall decreased depression was observed after the second genetic counseling session (P=0.013). Risk perception and anxiety decreased in the group diagnosed with benign variant/variant of uncertain significance (BV/VUS, 25/3) and increased in the group diagnosed with pathogenic variant (PV, 15). Risk perception and anxiety differed between the BV/VUS and PV groups (P<0.001 and P=0.03, respectively). Conclusion: The genetic counseling clinic at the SMC was effective in ameliorating the depression score. Assessment of survey results revealed different depression scores, feelings of guilt and anxiety, and different effects of the genetic counseling clinic, depending on the subgroups. Understanding the needs and psychological characteristics of different groups is necessary for improving genetic counseling services.

• Tuberculosis and Respiratory Diseases
• /
• v.60 no.4
• /
• pp.404-411
• /
• 2006

Purpose : Multidrug-resistant tuberculosis (MDR-TB) is an emerging threat to human beings. However, there is little data on the current status of MDR-TB in Korea. This study investigated the current status of MDR-TB in Korea using a survey of all the data from drug susceptibility tests (DST) performed across the country over the last three years. Method : The DST results between Jan. 2000 and Dec. 2002 from 7 laboratories, which were in charge of all antituberculous DSTs across the country as of March 2002, were collected and analyzed to determine the actual number of drug-resistant or MDR-TB patients, annual trend, degree and pattern of resistance against anti-TB drugs, etc. Results : Six laboratories used the absolute concentration method for DST and one used the proportional method. 59, 940 tests had been performed over the 3 year study period. The number of DST performed annually was 18,071, 19,950, and 21,919 in 2000-2002, respectively. The number of resistant tuberculosis patients (resistant against at least one anti-TB drug) had increased by 16.9% from 6,338 in 2000 to 7,409 in 2002. The rate of resistant tuberculosis among all DST results was 35.1% in 2000, 34.5% in 2001, and 33.8% in 2002. The number of MDR-TB patients (resistant against at least both isoniazid and rifampin) showed an increasing trend (14.5%) from 3,708 in 2000 to 4,245 in 2002. Conclusion : Approximately 4,000 MDR-TB cases are newly identified by DST annually and the number is showing an increasing trend. This study suggests that in order to cope with the current MDR-TB situation, the DST methods will need to be standardized and more aggressive measures will be required.

• Journal of Korean Society of Environmental Engineers
• /
• v.31 no.7
• /
• pp.505-514
• /
• 2009

Aqueous potassium salt of serine was proposed as an alternative $CO_2$ absorbent to monoethanolamine (MEA) and its $CO_2$ absorption characteristics were studied. The experiment has been conducted using screening test equipment with NDIR type gas analyzer and vapor-liquid equilibrium apparatus. $CO_2$ absorption/desorption rate and net amount of $CO_2$ absorbed in cyclic process are the criteria to assess the $CO_2$ absorption characteristics in this study. Effective $CO_2$ loading of potassium salt of serine and MEA are 0.425 and 0.230 respectively. Cyclic capacities are 0.354 and 0.298 for potassium salt of serine and MEA. The absorption rate of the potassium serinate decreased sharply at $CO_2$ loading is 0.1 and were maintained approximately at half of MEA. To enhance the absorption rate of aqueous potassium salt of serine, small quantities of rate promoters, namely piperazine and tetraethylenepentamine were blended, so that rich $CO_2$ loading were increased by 13.7% and 18.7% respectively. The rich $CO_2$ loading of potassium salt of serine was 29.2% and 35.0% higher than those of aqueous sodium and lithium salt of serine, respectively. The absorption rate of potassium salt of valine and isoleucine which have similar molecular structures to serine were lower than that of serine because of the presence of bulky side group. Precipitation phenomena during $CO_2$ absorption were discussed by the aid of literatures.

• Pediatric Infection and Vaccine
• /
• v.9 no.2
• /
• pp.175-181
• /
• 2002

Purpose : Scrub typhus(tsutsugamushi disease) is a febrile disease characterized by fever, rash, eschar, lymphadenopathy. Therapy with tetracycline(doxycycline) or chloramphenicol is currently recommended for the treatment for scrub typhus. But there are limitations in usage a tetracycline(doxycycline) for scrub typhus in the children. Recently, there was a report that azithromycin, a macrolide antibiotic was used for scrub typhus in pregnant woman successfully. So we evaluated the effectiveness of the Clarithromycin, other a macrolide antibiotic, for scrub typhus. Methods : Seven patients with scrub typhus at department of internal medicine and three patients with scrub typhus at department of pediatrics Masan Fatima Hospital were involved for this study. A serologic diagnosis for scrub typhus were performed by use of passive hemagglutination test. Clarithromycin(Abbott Laboratories, North Chicago, IL, USA) was administrated orally in a daily dose of 500 mg for adult patients and 15 mg/kg/bid/day for pediatric patients. Results : There were 7 cases of adult patients, varying from 28 to 76 years of age and 3 cases of pediatirc patients, varying from 4 to 7 years of age with scrub typhus. All of cases had fever, myalgia, headache, rash, eschar. Seven cases had positive passive hemagglutination test and eight cases had abnormal liver function. Mean duration for the removal of fever after medication was 1.3 day(1~2 days) and all cases were recovered without complications. Conclusion : Our results suggest that Clarithromycin therapy may be effective for scrub typhus.