• Environmental Analysis Health and Toxicology
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• v.29
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• pp.15.1-15.7
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• 2014

Objectives This paper tried to review a recent research trend for the environmental exposure of engineered nanomaterials (ENMs) and its removal efficiency in the nanowaste treatment plants. Methods The studies on the predicted environmental concentrations (PEC) of ENMs obtained by exposure modeling and treatment (or removal) efficiency in nanowaste treatment facilities, such as wastewater treatment plant (WTP) and waste incineration plant (WIP) were investigated. The studies on the landfill of nanowastes also were investigated. Results The Swiss Federal Laboratories for Materials Science and Technology group has led the way in developing methods for estimating ENM production and emissions. The PEC values are available for surface water, wastewater treatment plant effluents, biosolids, sediments, soils, and air. Based on the PEC modeling, the major routes for the environmental exposure of the ENMs were found as WTP effluents/sludge. The ENMs entered in the WTP were 90-99% removed and accumulated in the activated sludge and sludge cake. Additionally, the waste ash released from the WIP contain ENMs. Ultimately, landfills are the likely final destination of the disposed sludge or discarded ENMs products. Conclusions Although the removal efficiency of the ENMs using nanowaste treatment facilities is acceptable, the ENMs were accumulated on the sludge and then finally moved to the landfill. Therefore, the monitoring for the ENMs in the environment where the WTP effluent is discharged or biomass disposed is required to increase our knowledge on the fate and transport of the ENMs and to prevent the unintentional exposure (release) in the environment.

• International Journal of Control, Automation, and Systems
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• v.4 no.3
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• pp.382-393
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• 2006

Mechanical system dynamics plays an important role in the area of computational structural biology. Elastic network models (ENMs) for macromolecules (e.g., polymers, proteins, and nucleic acids such as DNA and RNA) have been developed to understand the relationship between their structure and biological function. For example. a protein, which is basically a folded polypeptide chain, can be simply modeled as a mass-spring system from the mechanical viewpoint. Since the conformational flexibility of a protein is dominantly subject to its chemical bond interactions (e.g., covalent bonds, salt bridges, and hydrogen bonds), these constraints can be modeled as linear spring connections between spatially proximal representatives in a variety of coarse-grained ENMs. Coarse-graining approaches enable one to simulate harmonic and anharmonic motions of large macromolecules in a PC, while all-atom based molecular dynamics (MD) simulation has been conventionally performed with an aid of supercomputer. A harmonic analysis of a macroscopic mechanical system, called normal mode analysis, has been adopted to analyze thermal fluctuations of a microscopic biological system around its equilibrium state. Furthermore, a structure-based system optimization, called elastic network interpolation, has been developed to predict nonlinear transition (or folding) pathways between two different functional states of a same macromolecule. The good agreement of simulation and experiment allows the employment of coarse-grained ENMs as a versatile tool for the study of macromolecular dynamics.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.11
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• pp.634-640
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• 2017

Toxicity and fate assessment is necessary in the evaluation of the environmental, health and safety risks of engineered nanomaaterials (ENMs). Therefore, in order to ensure the reproducibility, reliability and relevance of ENMs toxicity results, stable and monomodal dispersion protocols in toxicity test media are needed. Zinc oxide nanoparticles (nZnO) are widely used in various products such as cosmetic products, paper, paints etc. In this study, nZnO dispersions in ecotoxicity test media were produced by following a series of steps of modified National Institute of Standards and Technology (NIST) Special publication 1200-5. In addition, natural organic matter (humic acid (HA)) was used as a stabilizing agent to disperse nZnO in the test media. The hydrodynamic diameters (HDD) of the nZnO in dispersion ranged between 150 and 200 nm according to the dynamic light scattering (DLS) measurement. Based on these dispersions in ecotoxicity test using ecological species (Oryzias latipes, Daphnia magna, Pseudokirchneriella subcapitata and Chironomusus riparius), dispersion protocol was found to have a considerable potential in ecotoxicity test of ENMs.

• Journal of Korea Society of Waste Management
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• v.35 no.7
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• pp.670-682
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• 2018

Engineered nanomaterials (ENMs) can be released to humans and the environment through the generation of waste containing engineered nanomaterials (WCNMs) and the use and disposal of nano-products. Nanoparticles can also be introduced intentionally or unintentionally into waste streams. This study examined WCNMs in domestic industries, and target nanomaterials, such as silicon dioxide, titanium oxide, zinc oxide, nano silver, and carbon nanotubes (CNTs), were selected. We tested 48 samples, such as dust, sludge, ash, and by-products from manufacturing facilities and waste treatment facilities. We analyzed leaching and content concentrations for heavy metals and hazardous constituents of the waste. Chemical compositions were also measured by XRD and XRF, and the unique properties of nano-waste were identified by using a particle size distribution analyzer and TEM. The dust and sludge generated from manufacturing facilities and the use of nanomaterials showed higher concentrations of metals such as lead, arsenic, chromium, barium, and zinc. Oiled cloths from facilities using nano silver revealed high concentrations of copper, and the leaching concentrations of copper and lead in fly ash were higher than those in bottom ash. In XRF measurements at the facilities, we detected compounds such as silicon dioxide, sulfur trioxide, calcium oxide, titanium dioxide, and zinc oxide. We found several chemicals such as calcium oxide and silicon dioxide in the bottom ash of waste incinerators.

• Korean Journal of Acupuncture
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• v.23 no.4
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• pp.59-65
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• 2006

Objectives : By comparing the correspondence of Three Eums and Yangs (三陰三陽) to calendr in ${\ulcorner}Somun\;Make'ae{\lrcorner}$ with twelve principal divinatory symbols, this paper intends to explain the exterior and interior of meridian system using the phenomena of the trigrams from Juyeok(卦). It also tries to relate the phenomena of the trigrams with the characteristics of the original Gi (本氣) of Three Em and Yangs tough the interpretation of Three Eums and Yangs assigned to twelve principal divinatory symbols. Methods : This paper compares the correspondence of Three Eums and Yangs to calendar in ${\ulcorner}Somun\;Make'ae{\lrcorner}$ with twelve principal divinatory symbols. By this, it traces the making of the exterior and interior relationship between Taeeum (太陰)-Yangmyeong (陽明), Soeum (少陰)-Taeyang (太陽), and Gworeum (厥陰)-Soyang (少陽) through the phenomena of trigrams assigned to Three Eums and Yangs. It also interprets Three Em and Yangs assigned to twelve principal divinatory symbols, using the original Gi of the six atmospheric influences(六氣). Results and Conclusions : Three Eums and Yangs in ${\ulcorner}Somun\;Make'ae{\lrcorner}$ signify the six meridians of the leg. Soeum (少陰) is assigned to October in ${\ulcorner}Somun\;Make'ae{\lrcorner}$ but it is more appropriate to assign it to July. If Soeum (少陰) is assigned to July, Three Eums and Yangs have phenoma of the trigrams with Em and Yang lines (陽爻) counter to each other, and can be explained as the exterior and interior relationship. lastly, in case of Three Eums and Yangs assigned to twelve principal divinatory symbols, the phenomena of the trigrams can be interpreted as the original Gi of Three Eums and Yangs.

• Journal of Korean Society of Environmental Engineers
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• v.38 no.7
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• pp.395-401
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• 2016

Nano-saftey has become an emerging issue recently, because of the broad use of nanomaterials in nano-industries and commercial areas. For a sustainable development in the nano-industry, active studies on nano-safety should be executed, especially on the potential risks in engineered nanomaterials (ENMs). Although acute and chronic assessments of nanomaterials have been extensively studied in many studies, multigenerational studies are very scarce. Overall, multigenerational studies have progressed as two different trends, studying post-generational effects or trans-generation effects. This study intended to suggest further nano-safety studies based on the trends and limitations of current ones. Through a comparative analysis, we investigated peer-reviewed multigenerational studies that used nanomaterials. Thirteen studies on post-generation effects confirmed generational nano-toxicity via several bioassays, such as mortality, fertility, and behavioral assays. Seven studies on trans-generation effects demonstrated nanomaterial pathways to next generations, using imaging techniques. Until now, mechanisms for post-generational nano-toxicity has been rarely proposed. Thus, we propose that complementary studies on such mechanisms are imperative for future studies.