• Korean journal of applied entomology
• /
• v.42 no.3
• /
• pp.241-248
• /
• 2003

The aphid-eating gall-midge, Aphidoletes aphidimyza (Rondani), as predator of aphids was wildly used as one of the biological control agents for control of several kinds of aphids. Their some kinds of biological characteristics were examined. The developmental periods of A. aphidimyza from egg to adult with the green peach aphid as prey were 40 and 12 days at 15$^{\circ}C$ and 30$^{\circ}C$, respectively. Supplying the cotton aphid as prey, their developmental periods were shorter than with the green peach aphid. In case of the preservation of pupa in the cold condition, emergence rates were over 90% for 1 and 2 weeks at 5$^{\circ}C$ and l0$^{\circ}C$, respectively. Adult females of A. aphidimyza began mating and laying eggs at 2-3 days after emergence, and they laid about 200 eggs for lo days of average life span. Most of adults were emerged from pupa at 6 to 8 pm during a day, and they mainly acted in the early night.

• Macromolecular Research
• /
• v.17 no.1
• /
• pp.44-50
• /
• 2009

Rigid polyurethane foams (PUF)s were synthesized with environmentally friendly blowing agents such as a cyclopentane/distilled water (10.0/1.0, pphp) mixture and distilled water only for four different silicone surfactants having different silicone/polyether ratios. An attempt was made to reduce the thermal conductivities of the PUF samples by varying the concentration and the silicone/polyether ratio of the various silicone surfactants. The scanning electron microscopy (SEM) results indicated an optimum concentration of the silicone surfactant of about 1.5 to 2.5 phpp for various surfactants to reduce the cell size and lower the thermal conductivity. The silicone surfactant having a higher silicone/polymer ratio showed a smaller cell size and, therefore, demonstrated the lower thermal conductivity of the PUF samples. From the relation between the thermal conductivity and the cell size of the PUF samples, the smaller cell size improved the thermal insulation property of the rigid PUF for both the PUF samples blown by the cyclopentane/distilled water (10.0/1.0, pphp) mixture and distilled water only. If the blowing agent is fixed, then the cell size is an important factor to decrease the thermal conductivity of the PUF samples. These results indicated that rigid PUF samples having lower thermal conductivity can be obtained by choosing a silicone surfactant containing a higher silicone/polyether ratio, as well as an optimum content of the surfactant.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.34 no.3
• /
• pp.183-188
• /
• 2008

Initial screening assay for depigmenting agents includes in vitro mushroom tyrosinase assay and antioxidant assay. Based on this screening result, melanin synthesis in melanocyte, in screened samples, is further measured. Measuring cellular melanin needs time, human resource, and skills. Therefore initial screening method should be reliable. We examined, 34 Chinese herbs, correlated the screening assay methods with cellular melanin. No reliable relationship was observed between factors, indicating the limitation in the use of these assays, probably due to the complexicity of melanogenesis.

• Macromolecular Research
• /
• v.17 no.11
• /
• pp.856-862
• /
• 2009

This study examined the effects of liquid and solid additives on the morphological, mechanical and thermal insulating properties of rigid polyurethane foams (PUFs). The PUFs synthesized with tetramethylsilane (TEMS) as a liquid-type additive showed a smaller average cell size and lower thermal conductivity than those with the aerosil 200 and clay 30B as solid-type additives. When TEMS was added, the average cell size of the PUF became more uniform and finer due to the reduced surface tension of the polymer solution, which increased the nucleation rate and number of bubbles produced and reduced cell size. The PUFs with TEMS showed the highest closed cell contents among the PUFs prepared using TEMS, aerosil 200 and clay 30B. This suggests that the insulation properties of PUF can be determined by both the size of the cell structure and the amount of closed cell contents in the system. The compression and flexural strengths of the PUF increased slightly when the aerosil 200, clay 30B and TEMS were added compared those of the neat PUF. The reaction profiles of the PUFs showed a similar gel and tack tree time with the reaction time among the PUFs synthesized with three different additives and neat PUF. This suggests that the nucleating additives used in this study do not affect the bubble growth of the chemical reaction, and the additives may act as nucleating agents during the formation of PUF. From the above results of the cell size, thermal conductivity, closed cell contents and reaction profile of the PUFs, liquid-type nucleating agent, such as TEMS, is more effective in decreasing the thermal conductivity of the PUF than solid-type nucleating agent, such as aerosil 200 and clay 30B.

• Safety and Health at Work
• /
• v.14 no.4
• /
• pp.347-357
• /
• 2023

Introduction: The COVID-19 pandemic turned biological hazards in the working environment into a global concern. This systematized review of published reviews aimed to provide a comprehensive overview of the specific jobs and categories of workers exposed to biological hazards with the related prevention. Methods: We extracted reviews published in English and French in PubMed, Embase, and Web of Science. Two authors, working independently, subsequently screened the potentially relevant titles and abstracts recovered (step 1) and then examined relevant full texts (step 2). Disagreements were resolved by consensus. We built tables summarizing populations of exposed workers, types of hazards, types of outcomes (types of health issues, means of prevention), and routes of transmission. Results: Of 1426 studies initially identified, 79 studies by authors from every continent were selected, mostly published after 2010 (n = 63, 79.7%). About half of the reviews dealt with infectious hazards alone (n = 38, 48.1%). The industrial sectors identified involved healthcare alone (n = 16), laboratories (n = 10), agriculture (including the animal, vegetable, and grain sectors, n = 32), waste (n = 10), in addition of 11 studies without specific sectors. The results also highlighted a range of hazards (infectious and noninfectious agents, endotoxins, bioaerosols, organic dust, and emerging agents). Conclusion: This systematized overview allowed to list the populations of workers exposed to biological hazards and underlined how prevention measures in the healthcare and laboratory sectors were usually well defined and controlled, although this was not the case in the agriculture and waste sectors. Further studies are necessary to quantify these risks and implement prevention measures that can be applied in every country.

• Toxicological Research
• /
• v.6 no.1
• /
• pp.63-73
• /
• 1990

Human exposure to environmental carcinogens can be detected by a number of methods including immunoassay, $^{32}P-postlabeling$ assay, and fluorescence technique. These assays have been applied to measure biological markers of carcinogen-adducts formed with macromolecules such as DNA, RNA and protein. In an attempt to investigate causal relationships between carcinogen exposure and tumor formation, specific carcinogen-adducts have been quantitated from human tissues and body fluids of cancer patients, occupational workers heavily exposed to certain carcinogens, smokers and controls. Carcinogens studied for biological human monitoring include benzo(a)pyrene, aflatoxin B1, UV light, ethylene oxide, 8-methoxypsoralen, 4-aminobiphenyl, vinyl choride, N-nitrosamine, cisplatin and other chemotherapeutic agents. Relevance of human monitoring for cancer research, progress in this field, methods to detect carcinogen-adducts are reviewed here. It is hoped that these approaches will be used for the risk assessment of carcinogen exposure, cancer etiology study and cancer prevention in humans.

• Toxicological Research
• /
• v.6 no.1
• /
• pp.61-61
• /
• 1990

Human exposure to environmental carcinogens can be detected by a number of methods including immunoassay, $^{32}P$-postlabeling assay, and fluorescence technique. These assays have been applied to measure biological markers of carcinogen-adducts formed with macromolecules such as DNA, RNA and protein. In an attempt to investigate causal relation ships between carcinogen exposure and tumor formation, specific carcinogen-adducts have been quantitated from human tissues and body fluids of cancer patients, occupational workers heavily exposed to certain carcinogens, smokers and controls. Carcinogens studied for biological human monitoring include benzo(a)pyrene, aflatoxin B1, UV light, ethylene oxide, 8-methoxypsoralen, 4-aminobiphenyl, vinyl chloride, N-nitrosamine, cisplatin and other chemotherapeutic agents. Relevance of human monitoring for cancer research, progress in this field, methods to detect carcinogen-adducts are reviewed here. It is hoped that these approaches will be used for the risk assessment of carcinogen exposure, cancer etiology study and cancer prevention in humans.

• Polymer Science and Technology
• /
• v.23 no.2
• /
• pp.174-184
• /
• 2012

• Korean Journal of Biological Psychiatry
• /
• v.8 no.1
• /
• pp.71-78
• /
• 2001

The current understanding of the neurobiology of anxiety is generally based on experimental animal model, empirical effective psychopharmacological agents, chemical and naturalistic challenge paradigms, and psychoendocinological assessment. This article focuses on reviewing neuroanantomical, neuroendocinological and neurofunctional research of anxiety disorder. In the decade ahead, we anticipate that extension of current research and the new integrated approach promise novel insight into mechanism of anxiety.

• Korean Journal of Biological Psychiatry
• /
• v.3 no.2
• /
• pp.156-161
• /
• 1996

Many pregnant women have to receive psychotropic medication during pregnancy and lactation period, despite the proven and assumed risks to the fetus ar neonate. A brief summary of drug metabolism and pharmacodynamics is given. Principles and quidelines of using psychotropic agents during pregancy and lactation period are presented for psychotic disorders, bipolar affective disorders. depression and anxiety disorders, with due consideration for relative benefits and risks of choosing among psychotropic drugs and alternative treatments.