• Mycobiology
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• 제39권3호
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• pp.143-150
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• 2011

The basidiomycete fungus Cryptococcus neoformans is an important pathogen of immunocompromised people. The ability of the fungus to sense its environment is critical for proliferation and the generation of infectious propagules, as well as for adaptation to the mammalian host during infection. The conserved cAMP/protein kinase A pathway makes an important contribution to sensing, as demonstrated by the phenotypes of mutants with pathway defects. These phenotypes include loss of the ability to mate and to elaborate the key virulence factors capsule and melanin. This review summarizes recent work that reveals new targets of the pathway, new phenotypic consequences of signaling defects, and a more detailed understanding of connections with other aspects of cryptococcal biology including iron regulation, pH sensing, and stress.

• Journal of Communications and Networks
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• 제15권6호
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• pp.569-575
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• 2013

In this paper, we present a photonic approach for generating highly stable coherent sub-terahertz (THz) signals for wireless communications. As proof-of-concept we transmit data at 100 GHz carrier frequency using on-off keying modulation and heterodyne detection. The sub-THz carrier signals are generated by photo-mixing two optical carrier signals at different frequencies, extracted from an optical frequency comb. We introduce a novel system to stabilize the phase of the optical carrier signals. Error-free transmission is successfully achieved up to a bit rate of 8.5 Gbit/s at 100 GHz.

• Bulletin of the Korean Chemical Society
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• 제8권4호
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• pp.276-280
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• 1987

Several chiral potassium B-alkyl-9-boratabicyclo[3.3.1]nonanes $(K\; B-R^*-9-BBNH)$ and potassium B-alkoxy-9-boratabicyclo[3.3.1]nonanes $(K \;B-OR^*-9-BBNH)$ were synthesized by treatment of the corresponding trialkylboranes and dialkylmonoalkoxyboranes with a small excess of potassium hydride. The chiral B-alkoxy derivatives generally reduce representative ketones, such as acetophenone and 3-methyl-2-butanone, with greater optical induction than the corresponding B-alkyl derivatives, suggesting the involvement of the oxygen atom in the control process for asymmetric synthesis.

• 한국산업보건학회지
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• 제20권3호
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• pp.184-191
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• 2010

Although the usage of nanomaterials including carbon nanotubes (CNTs) has increased in various fields, scientific researches on workers' exposures and controls of these materials are very limited. The purpose of this study was to compare the airborne nanoparticles concentrations from two university laboratories conducting experiments of CNTs growth based on containment of thermal chemical vapor deposition (CVD). Airborne nanoparticle concentrations in three metrics (surface area concentration, particle number concentration, and mass concentrations) were measured by task using three direct reading instruments. In a laboratory where CVD was not contained, the surface area concentration, number concentration and mass(PM$_1$) concentration of airborne nanoparticles were 1.5 to 3.5 times higher than those in the other laboratory where CVD was confined. The ratio of PM$_1$ concentration to total suspended particles(TSP) in the laboratory where CVD was not confined was about 4 times higher than that in the other laboratory. This indicates that CVD is a major source of airbone nanoparticles in the CNTs growth laboratories. In conclusion, researchers performing CNTs growth experiments in these laboratories were exposed to airborne nanoparticles levels higher than background levels, and their exposures in a laboratory with the unconfined CVD were higher than those in the other laboratory with the confined CVD. It is recommended that in the CNTs growth laboratories adequate controls including containment of CVD be implemented for minimizing researchers' exposures to airborne nanoparticles.

• Journal of Preventive Medicine and Public Health
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• 제38권4호
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• pp.449-456
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• 2005

Objectives : The biosafety level (BSL) practiced in microbiology laboratories in Korea according to the laboratory biosafety manual published by the World Health Organization (WHO) was evaluated using the data obtained by a survey. Methods : Under the advise of Clinical Laboratory Physicians, 144 types of microorganisms were screened based on the guidelines of biosafety in microbiological and biomedical laboratories published by the US Center for Disease Control and Prevention and classified into 1-4 risk groups. A questionnaire containing 21 questions in 5 areas was developed using the biosafety manual by published WHO. Of the 1,876 different organizations sent the survey, 563 responded to the survey (response rate: 30.0%). The species of microoganisms handled by as well as the biosafety level in microbiology laboratories were analyzed. Results : There were 123 species of microorganisms handled in microbiology labs in Korea. The BSL required in 512 microbiology labs was answered by the survey responders as the first grade in 33 labs (6.4%), 2nd in 437 (85.4%), 3rd in 42 (8.2%), and 4th in none. The average number of items satisfied was 12.2, showing only a 57.9% satisfactory rate and normal distribution. Conclusions : The state of overall observance of BSL in most microbiology labs of Korea was evaluated as lagging compared with the standard set up by WHO. Therefore, the Korean government need to produce and distribute a biosafety manual in microbiology laboratories and make efforts to prevent this threat through measures such as training in biosafety in microbiology labs.

• 한국산업보건학회지
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• 제4권1호
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• pp.103-116
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• 1994

This study was conducted to evaluate accuracy and precision of reference values used for quality control of the Korean industrial hygiene laboratory for three rounds. Factors affecting on accuracy and precision, including analytical procedures, were investigated. The results are summarized as follows. 1. Pooled relative standard deviation of reference values analyzed by reference laboratories was 2.01-5.91%, and that by both reference laboratories and participated laboratories was 3.18-6.63%. Better results were obtained when results of reference laboratories were employed. 2. Significant relationship was indicated between analytical precision and concentration of materials in samples. Variation increased by decreasing sample concentration. 3. Recoveries of lead and cadmium were about 98.6% and 99.8% respectively. There was a significant difference between lead values with and without recovery correction. 4. Organic solvent results corrected by desorption efficiency only and those corrected by Both internal standards and desorption efficiency were more accurate than those uncorrected. But, the latter was the best.

• 대한임상검사과학회지
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• 제42권1호
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• pp.16-21
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• 2010

It has been well known that organic industrial solvents such as toluene, xylene and styrene are environmental health hazards causing occupational diseases to workers. The detection of biological metabolites of toluene, xylene and styrene in blood, urine, breast milk, saliva, and hair of workers exposed to these organic industrial solvents is a useful tool for assessing the amount of organic industrial solvents. Therefor, the external analytical quality assurance program is extremely important work for increasing reliability of the data analyzed in the special health examination laboratory. We evaluated the results of analysis by Korean analytical quality assurance program from the second half 2007 to the first half 2009. The number of participants for analytical quality assurance program for both mandatory item and one of optional items, hippuric acid and methylhippuric acid were 116-122, 116-122 and 105-115 laboratories, respectively. The proficient rate of the special health examination laboratories analyzed both mandatory item and optional item, hippuric acid and methylhippuric acid were 92-98%, 92-98% and 96-98%, respectively. We can conclude from our data that the analytical quality assurance program is a essential tool for improvement of reliability on the data analyzed in the special health examination laboratories.

• 한국약용작물학회:학술대회논문집
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• 한국약용작물학회 2007년도 추계학술발표회
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• pp.299.2-299.2
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• 2007

• International Journal of Industrial Entomology and Biomaterials
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• 제32권1호
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• pp.12-25
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• 2016

Recently, research investment in the improvement of food safety as a food source and specializing of nutritional source of edible insects is being actively conducted. Cricket especially has been attracting considerable interest in entomophagy; however, research on the safety assessment of cricket is limited. This study investigated the effects of cricket ethanol extract when orally administrated in Sprague-Dawley rats. Here, we performed a 4 wk repeated oral dose toxicity test in Sprague-Dawley rats following the Organization for Economic Cooperation and Development test guidelines 407 under Good Laboratory Practice regulation. Rats were randomly allocated 4 groups: vehicle control, 250, 500, 1,000 mg/kg test groups and administrated based on body weight for 28 d. The animals were observed for mortalities and clinical signs, body weight changes, food and water consumption. At the end of treatment period, blood and urine were collected and analyzed. Subsequently, the animals were sacrificed and subjected to gross pathological examination and organ weight measurement. The organs were preserved for histopathological examination. The results showed that there were no systemic toxicological effects related with the cricket ethanol extract in the 4 wk oral repeated dose toxicity study. It is considered that NOAEL of cricket ethanol extract is greater than 1,000 mg/kg/d and there was no target organ detected.

• 대한임상검사과학회지
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• 제44권3호
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• pp.155-165
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• 2012

The purpose of this study was to develop a multiplex PCR for the detection of aac(6')-Ib, aph(3')-Ia, and ant(2")-Ia; the genes that encode the most clinically relevant aminoglycoside modifying enzymes (AMEs) in Gram-negative bacteria. Clinical isolates of 80 E. coli and 23 K. pneumoniae from tertiary university hospital were tested by multiplex PCR. The most prevalent AME gene was aac(6')-Ib which was found in 22.3% of the isolates. Of the total 80 E. coli isolates, 1 isolate was found to contain both aph(3')-Ia and ant(2")-Ia simultaneouly. Of the total 23 K. pneumoniae isolates, 2 isolates were found to contain both aac(6')-Ib and aph(3')-Ia, and 1 isolate was found to contain both aac(6')-Ib and ant(2")-Ia simultaneously. Annual (2005~2009) analysis of isolates that contain the AME genes were of no correlation. The sensitivity and specificity of multiplex PCR in detecting AME genes was 94.4% (34 of 36 cases) and 100%, respectively. We suggest the multiplex PCR method we developed could be highly sensitive and specific in detecting the AME genes of E. coli and K. pneumoniae. This study could be the first published investigation in which the multiplex PCR method detects aac(6')-Ib, aph(3')-Ia, and ant(2")-Ia genes.