Purpose: Several studies have reported an association between lead exposure and increased risk of allergic sensitization and asthma. According to the Centers for Disease Control and Prevention guidelines, An elevated blood lead level (BLL) is defined as a BLL of ≥ 5 µg/dL. However, no safe BLL has been identified, and it is controversial whether a BLL of < 5 µg/dL affects the risk of asthma. Methods: We examined asthma prevalences and BLLs using data from the 2010-2013 Korea National Health and Nutrition Examination Survey (KNHANES), which was a cross-sectional survey of 1,478 adolescence (aged 10-19 years) throughout the country. The adjusted odds ratios (ORs) (with 95% confidence intervals [CIs]) for the prevalence of asthma in adolescence with elevated BLLs were calculated by complex samples multivariate logistic regression analysis. The presence of asthma was based on self-reported, physician-diagnosed asthma in the Health Interview Surveys. Results: The mean of total BLLs was 1.33 μg/dL. Overall, 5.1% (n= 71) of the subjects were physician diagnosed asthma. In the model controlling for population characteristics, the adjusted odds ratio for asthma per 1 μg/dL increase in blood lead was 1.94, 95% CI (1.06, 3.57), and stronger associations were observed among boys (adjusted OR, 2.31; 95% CI, [1.18, 4.51]). The group of BLL≥ 2 μg/dL was associated with an OR of 2.84 (95% CI, 1.06, 7.63) for asthma, after adjusting for potential confounding factors in boys. Conclusion: Our results suggest an association between total BLLs and asthma in Korean adolescent boys, although confirmation is warranted in further prospective studies.

Thermoplastic polyurethane (TPU) elastomer is used as an encapsulant in undersea sonar devices. A new material for sonar encapsulant exhibiting better mechanical strength than TPU along with a lower swelling ratio for seawater and oil is required to prolong its application. TPU grafted silica nanoparticles (TPU-g-silica) were prepared and then they were melt mixed with TPU to fabricate desirable composites for underwater applications. The composite containing silica nanoparticles exhibited better tensile strength and lower swelling ratios in the seawater and oil than TPU regardless of the surface treatment of the silica particles. At fixed silica content in the composite, the TPU/TPU-g-silica composite exhibited better tensile strength and lower swelling ratio than the TPU composite with the pristine silica particles. Furthermore, the TPU/TPU-g-silica composite exhibited enhanced tensile strength as compared to TPU after being impregnated with oil.

Today, many enterprises have invested heavily for the part of information security in order to protect the internal critical information assets and the business agility. However, there is a big problem that big budget and too many manpower are needed to set the internal corporate network up to the same high level of defense for all of part. On the distributed enterprise networks in this paper, a defense model for effective and rapid response on the IP spoofing attack was designed to protect the enterprise network through the exchange of information between the trust hosts when an attacker attacked any target system using other trusted host.

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