• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.20 no.3
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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 Korean Society of Occupational and Environmental Hygiene
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• v.23 no.3
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• pp.266-272
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• 2013

Objectives: This study aimed to evaluate the effects of low-level exposure to toluene on T lymphocytes subpopulations.s. Methods: The study lasted from April to October 2010. The subjects were 390 male workers, among whom 137 were chronically exposed to toluene in video-tape manufacturing factories and 253 were controls had never been occupationally exposed to hazardous chemicals. The subpoupulations of CD4+, CD8+, CD16+ (natural killer cells) and total (CD3+) T lymphocytes were examined by two-color staining using monoclonal antibodies. The general and job characteristics of subjects were assessed through a self-administered questionnaire. Results: There was no significant difference in general and job characteristics between both groups. No significant difference in lipid peroxide level was observed between the control and exposed workers, but the concentration of hydrogen peroxide was significantly higher in the exposed workers. The numbers of CD16+ T lymphocytes in controls were significantly higher than those in exposed workers, but no significant differences were found in CD4+, CD8+ and CD3+ T lymphocytes. Hydrogen peroxide levels showed a significantly negative correlation with CD8+ (r = -0.29, p < 0.01), CD16+ (r = -0.56, p < 0.01) and CD3+(r = -0.22. p < 0.01), and toluene levels was significantly negative correlated with CD3+ (r = -0.29, p < 0.05). Conclusions: Our results suggest that chronic low-level exposure to toluene affects cell-mediated immunity and the effects might mediate through ROSs (Reactive Oxygen Species) such as hydrogen peroxide.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.1
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• pp.377-386
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• 2013

As apartments have been made into high-rise buildings, the residents in the buildings have become to enjoy the benefits. On the contrary, the users of buildings on the back have become to experience many problems in residential environments. This research studied on measures to improve height control systems focusing on the heights of apartments in order to figure out the impact of apartments on city scenery. This study concluded that, to solve these problems, a general system to control heights should be prepared to solve the problem of visual blocking and for apartment complexes or buildings in coastal areas, regulations for height controls suitable to them should be separately prepared thereby controlling systems related to height controls as a whole instead of those many different systems relating to heights.

• Toxicological Research
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• v.16 no.1
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• pp.33-37
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• 2000

Hershberger assay is known as one of the in vivo-short-term scrrning assays for endocrine disrupting chemicals (EDCs), but this method is not a validated test system. In the present study, the establishment of Hershberger assay to detect EDCs was tried using a model substance, di(n-butyl)phthalate (DBP), a plasticizer for plastics. Thirty-six immature male rats were randomly assigned to six groups: DBP 0, 40, 200, and 1000mg/kg, a positive control (flutamide 20 mg/kg), and a combination group(DBP 1000mg/kg and testosterone 50 ug/kg). DBP and flutamide were administered by gavage to male rats from day 21 to 40 post partum. Testosterone was subcutaneously injected during the same period. We evaluated body weigth gain, weights of ventral prostate, seminal vesicle, and levator ani and bulvocavernous muscle, and serum concentrations of testosterone and lutenizing hormone in male rats. The weights of seminal vesicle and levator ani and bulvocavernous muscle of males receiving 1000mg/kg of DBP was significantly lower than controls. There was no effect of DBP-treatment on body weight gain, prostate weight, and hormone concentrations. In the positive control group, the weights of seminal vesicle and levator ani and bulvocavernous muscle of males receiving 20mg/kg of flutamide were significantly lower than controls. In the combination group, there was no effect of co-treatment of DBP and testosterone on all parameters effect against DBP. This method was found to be a useful short-term screening assay system for EDCs.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.13
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• pp.5337-5341
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• 2015

Background: Individual susceptibility to cancer has been attributed to polymorphisms in xenobiotic metabolizing genes. To evaluate the association of the Leu432Val polymorphism of cytochrome P4501B1 (CYP1B1) with esophageal squamous cell carcinoma (ESCC), we conducted a case control study in Kashmir, India, an area with a relatively high incidence of ESCC. Materials and Methods: We recruited 404 histopathologically confirmed ESCC cases, and an equal number of controls, individually matched for sex, age and district of residence to respective cases. Information was obtained on various dietary, lifestyle and environmental factors in face to face interviews, using a structured questionnaire, from each subject. Genotypes were analysed by polymerase chain reaction, restriction fragment length polymorphism and sequencing of randomly selected samples. Conditional logistic regression models were used to calculate odds ratios (ORs) and 95% confidence intervals (95% CIs). Results: Among the three possible variants, we did not find any Leu432Leu genotype of CYP1B1 in the study population and the genotypic distribution of Val432Val and Leu432Val carriers was nearly equal in both cases (89.6% and 10.4%) and controls (88.9% and 11.1%) respectively. We did not find any risk associated with this polymorphism in the current study (OR = 0.64; 95% CI: 0.55 - 1.64). Conclusions: The study indicates that (Leu432Val) polymorphism of CYP1B1, is not associated with ESCC risk. However, replicative studies with larger sample size are needed to substantiate the findings.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.2
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• pp.723-726
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• 2013

Background: Breast cancer is worldwide the most common cancer in women and is a major public health problem. Genes with high or low penetrance are now clearly implicated in the onset of breast cancer, mostly the BRCA genes. All women in families at high risk of breast cancer do not develop tumours, even when they carry the familial mutation, suggesting the existence of genetic and environmental protective factors. Several studies have shown that consanguinity is linked to a decreased or an increased risk of breast cancer, but to the best of our knowledge, there is no study concerning the association between consanguinity and the occurrence of tumours in women with high risk of breast cancer. The objective of this study was to examine whether parental consanguinity in families with genetic predisposition to breast cancer affect the risk of siblings for having this cancer. Materials and Methods: Over a six-year period, 72 different patients with a histological diagnosis of breast or ovarian cancer from 42 families were recruited for genetic counselling to the Department of Medical Genetics, Rabat. Consanguinity rate was determined in cases and compared to the consanguinity rate in the Moroccan general population. Results: Consanguinity rates were 9.72% in patients and 15.3% in controls, but the difference was statistically not significant (p>0.001) and the mean coefficient of consanguinity was lower in breast cancer patients (0.0034) than in controls (0.0065). Conclusions: Despite the relatively small sample size of the current study, our results suggest that parental consanguinity in Moroccan women might not be associated with an altered risk of breast cancer. Large scale studies should be carried out to confirm our results and to develop public health programs.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.45 no.1
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• pp.59-70
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• 2000

In nature, plant diseases, insects and parasites (hereafter called as "pest") must be co-survived. The most common expression of co-survival of a host crop to the pest can be tolerance. With tolerance, chemical uses can be minimized and it protects environment and sustains host productivity and the minimum pest survival. Tolerance can be applicable in all living organisms including crop plants, lifestocks and even human beings. Tolerant system controls pest about 90 to 95% (this pest control system often be called as horizontal or partial resistance), while the use of chemicals or selection of high resistance controls pest 100% (the most expression of this control system is vertical resistance or true resistance). Controlling or eliminating the pests by either chemicals or vertical resistance create new problems in nature and destroy the co-survial balance of pest and host. Controlling pests through tolerance can only permit co-survive of pests and hosts. Tolerance is durable and environmentally-friend. Crop cultivars based on tolerance system are different from those developed by genetically modified organism (GMO) system. The former stabilizes genetic balance of a pest and a host crop in nature while the latter destabilizes the genetic balance due to 100% control. For three decades, the author has implemented the tolerance system in breeding maize cultivars against various pests in both tropical and temperate environments. Parasitic weed Striga species known as the greatest biological problem in agriculture has even been controlled through this system. The final effect of the tolerance can be an integrated genetic pest management (IGPM) without any chemical uses and it makes co-survival of pests in nature.in nature.

• Journal of Preventive Medicine and Public Health
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• v.29 no.1 s.52
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• pp.91-102
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• 1996

Low back pain patients and controls of shipyard workers were surveyed between June 1995 and September 1995 to identify risk factors of industrial low back pain. The patients were 17 male workers who had got medical treatment for over 3 days because of industrial back pain. Controls were 51 male workers who had not have musculoskeletal disorder for one year before the survey. By univariate analysis, the workers who did overtime work 4 times or more for the last 2 weeks showed odds ratio of 3.67 on low back pain with the workers who did less overtime work. Carrying heavy materials was also associated with the low back pain and the odds ratio increased with the increase of carrying weight. Work space and work posture were not associated with the low back pain significantly. The welder had higher odds ratio than the other workers on low back pain. The duration of employment and job satisfaction did not affect the risk of low back pain. Multiple logistic regression analysis showed that frequency of overtime work for the last 2 weeks and carrying heavy materials among the risk factors were associated significantly with the low back pain. We found that important risk factors of low back pain of shipyard workers are work intensity factors such as overtime work and carrying heavy weight.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.25 no.2
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• pp.108-115
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• 2015

Electro-mechanical actuator installed on aircraft consists of a decelerator which magnifies the torque in order to rotate an axis connected with aircraft control surface, a control section which controls the motor assembly through receiving orders from cockpit and a motor assembly which rotates the decelerator. Electro-mechanical actuator controls aircraft altitude, position, landing, takeoff, etc. It is an important part of a aircraft. Aircraft maneuvering causes vibrations to electro-mechanical actuator. Vibrations may result in structural fatigue. For that reason, it is necessary to analyze the system structural safety. In order to analyze the system structural safety. It is needed reasonable finite element model and structural response stress closed to real value. In this paper, analytic model is derived by using the simplified finite element model, and damping ratio which is closely related to response stress is derived by using modal test. So, we developed analytic model in less than 10 % error rate, compared with modal test. Vibration response stress close to real value was estimated from analytic model modified with modal experimental damping ratio. Estimation method for damping ratio with empirical formula was suggested partly. Finally, It was proved that electro-mechanical actuator had reasonable structure margin of safety at environmental random $3{\sigma}$ stress during life cycle.

• Proceedings of the KSRS Conference
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• 2002.10a
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• pp.229-234
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• 2002

Under the hostile influence of the extreme space environmental conditions due to the deep space and direct solar flux, the thermal control in space applications is especially of major importance. There are tight temperature range restrictions for electro-optical elements while on the other hand there are low power consumption requirements due to the limited energy sources on the spacecraft. So, we usually have strong requirement of thermal and power control module in space applications. In this paper, the design concept of a thermal and power control module in the MSC(Multi-Spectral Camera) system which will be a payload on KOMPSATII is described in terms of H/W & S/W. This thermal and power control module, called THTM(Thermal and Telemetry Module) in MSC, resides inside the PMU(Payload Management Unit) which is responsible for the proper management of the MSC payload for controlling and monitoring the temperature insides the EOS(Electro-Optic System) and gathering all the analog telemetry from all the MSC sub-units, etc. Particularly, the designed heater controller has the special mode of "duty cycle" in addition to normal closed loop control mode as usual. THTM controls heaters in open loop according to on/off set time designed through analysis in duty cycle mode in case of all thermistor failure whereas it controls heaters by comparing the thermistor value to temperature based on closed loop in normal mode. And a designed THTM provides a checking and protection method against the failure in thermal control command using the test pulse in command itself.