Exposure assessment of engineered nanomaterials in the workplace

Nanotechnology is a rapidly growing field and numerous products containing engineered nanomaterials are already in the market. With the increasing use of engineered nanomaterials, it is expected to increase the exposures to nanomaterials in the workplace. However, the researches on the exposure assessment of nanomaterials to humans and the environment are just a beginning step, as the nanotechnology industries are expanding. Questionnaire surveys conducted by various organizations reveal that many nanotechnology companies are searching for information on exposure measurement for the protection of workers who handle nanomaterials. We analyze the trends of researches on the occupational exposure measurement of engineered nanomaterials and investigate the methodologies of exposure assessment recommended by the related working groups. This work is expected to fill the gaps in knowledge on the exposure assessment of nanomaterials.     

Physicochemical properties and antioxidant activities of Korean traditional alcoholic beverage, yakju, enriched with mulberry

Mulberry fruits (Morus alba L.), rich in health beneficial compounds such as polyphenols, flavonoids, and anthocyananis, have traditionally been used as nutritional foodstuffs and fork medicines. In this study, physicochemical properties and antioxidant activities of a traditional Korean alcoholic beverage ``yakju' enriched with mulberry were evaluated. The beverage was enriched with smoothies prepared from Korean mulberry cultivars of Cheongilppong (CP), Suwonppong (SP), and Daesungppong (DP). In comparison to the control, an increase in alcohol content and total acidity and a decrease in sugar level in yakju enriched with mulberry were observed during 15 d of fermentation. The total polyphenol and total flavonoid content increased in the following order: DP yakju > SP yakju > CP yakju > control yakju. In contrast, the anthocyanin content decreased during the fermentation periods. The trans-resveratrol content of mulberry yakju increased during the fermentation and the resveratrol content of DP yakju (0.24 mg/L) was significantly higher than that of SP yakju (0.21 mg/L) and CP yakju (0.14 mg/L) on the 15th day of fermentation (P < 0.05). The antioxidant activities of mulberry yakju, which was assessed using the 1,1-diphenyl-2-picryl hydrazyl (DPPH), 2,2'-azino-bis-(3-ethylbenozothiazoline-6-sulfonic acid) (ABTS), ferric reducing antioxidant power (FRAP), and reducing power assays, decreased during the 1st day of fermentation and increased into thereafter. The increase in antioxidant activities of mulberry yakju might have been affected primarily by the total flavonoid and total polyphenol content with increasing alcohol concentration, as a good extractor, during the fermentation; however, the antioxidant activities may have also been affected by the total anthocyanin content up to the 1st day of fermentation. PRACTICAL APPLICATION: The physicochemical properties and antioxidant activities of a traditional Korean alcoholic beverage ``yakju' enriched with mulberry were investigated. This analysis is important for the potential applications of mulberry yakju as functional alcoholic drinks.     

Characteristics of milk tablets supplemented with nanopowdered eggshell or oyster shell

This study was performed to investigate the characteristics of milk tablets supplemented with nanopowdered eggshell (NPES) or nanopowdered oyster shell (NPOS). The particle size of NPES, NPOS, NPES with zinc (Zn‐NPES) and NPOS with activated zinc (Zn‐NPOS) ranged from 20 to 300 nm. The hardness of the milk tablets containing these calcium supplements did not differ significantly from that of the control milk tablets (P > 0.05). Regarding the sensory properties, the appearance, flavour, taste, texture and cumulative sensory score of all the test tablets were similar to those of the control tablets. In conclusion, the quality of all the test milk tablets was similar to that of the control.     

Anti‐inflammatory Potential of Quercetin‐3‐O‐β‐D‐(“2”‐galloyl)‐glucopyranoside and Quercetin Isolated from Diospyros kaki calyx via Suppression of MAP Signaling Molecules in LPS‐induced RAW 264.7 Macrophages

Diospyros kaki (DK) contains an abundance of flavonoids and has been used in folk medicine in Korea for centuries. Here, we report for the first time the anti‐inflammatory activities of Quercetin (QCT) and Quercetin 3‐O‐β‐(“2”‐galloyl)‐glucopyranoside (Q32G) isolated from DK. We have determine the no cytotoxicity of Q32G and QCT against RAW 264.7 cells up to concentration of 50 μM. QCT and Q32G demonstrated potent anti‐inflammatory activities by reducing expression of nitric oxide (NO), tumor necrosis factor (TNF)‐α, interleukin (IL)‐1β, IL‐6 inducible NO synthase (iNOS), cyclooxygenase (COX)‐2, and mitogen‐activated protein kinase (MAPKs) in mouse RAW 264.7 macrophages activated with lipopolysaccharide (LPS). Both QCT or Q32G could decrease cellular protein levels of COX‐2 and iNOS as well as secreted protein levels of NO, PGE₂, and cytokines (TNF‐α, IL‐1β, and IL‐6) in culture medium of LPS‐stimulated RAW 264.7 macrophages. Immunoblot analysis showed that QCT and Q32G suppressed LPS‐induced MAP kinase pathway proteins p‐p38, ERK, and JNK. This study revealed that QCT and Q32G have anti‐inflammatory potential, however Q32G possess comparable activity as that of QCT and could be use as adjuvant to treat inflammatory diseases.     

Face recognition using a fuzzy fisherface classifier

In this study, we are concerned with face recognition using fuzzy fisherface approach and its fuzzy set based augmentation. The well-known fisherface method is relatively insensitive to substantial variations in light direction, face pose, and facial expression. This is accomplished by using both principal component analysis and Fisher's linear discriminant analysis. What makes most of the methods of face recognition (including the fisherface approach) similar is an assumption about the same level of typicality (relevance) of each face to the corresponding class (category). We propose to incorporate a gradual level of assignment to class being regarded as a membership grade with anticipation that such discrimination helps improve classification results. More specifically, when operating on feature vectors resulting from the PCA transformation we complete a Fuzzy K-nearest neighbor class assignment that produces the corresponding degrees of class membership. The comprehensive experiments completed on ORL, Yale, and CNU (Chungbuk National University) face databases show improved classification rates and reduced sensitivity to variations between face images caused by changes in illumination and viewing directions. The performance is compared vis-à-vis other commonly used methods, such as eigenface and fisherface.     

A Simulated transportation problem for improved operational planning: An application in the trucking industry

This paper demonstrates the use of a simulated transportation method as an approach to developing an instructional guide that is operationally flexible and feasible for planning truck rental needs in a way to minimize costs. The informational impact of this approach aids not only the internal operations, but also external relations with truck renting companies by providing a more accurate measure of the anticipated demand on rental equipment, thus allowing the rental companies an opportunity to meet this demand.The results of the research conducted indicate the simulated transportation method is a reliable and valid planning instrument for minimizing transportation cost and generating useful information for management decision making.     

Hierarchical community classification and assessment of aquatic ecosystems using artificial neural networks

Benthic macroinvertebrate communities in stream ecosystems were assessed hierarchically through two-level classification methods of unsupervised learning. Two artificial neural networks were implemented in combination. Firstly, the self-organizing map (SOM) was used to reduce the dimension of community data, and secondly, the adaptive resonance theory (ART) was subsequently applied to the SOM to further classify the groups in different scales. Hierarchical grouping in community data efficiently reflected the impact of the environmental factors such as topographic conditions, levels of pollution, and sampling location and time across different scales. New community data not included in the training process were used to test the trained network model. The input data were appropriately grouped at different hierarchical levels by the trained networks, and correspondingly revealed the impact of environmental disturbances and temporal dynamics of communities. The hierarchical clusters based on a two-level classification method could be useful for assessing ecosystem quality and community variations caused by environmental disturbances.     

Raman spectroscopy as a tool for measuring mutual-diffusion coefficients in hydrogels

Raman spectroscopy has been exploited to characterize the diffusion properties of solutes in hydrogels. Raman active vibrations were used as intrinsic probes of the solute concentration along gel cylinders. The resulting one-dimensional solute distribution, characterized as a function of both time and space, could be analyzed with a model based on Fick's diffusion law, and the mutual-diffusion coefficient (Dm) was then determined. To illustrate the potential of this approach, we measured the Dm of two polyethylene glycols (PEG) in Ca-alginate gels. In this case, the intensity of the CH stretching band was used to obtain the concentration profiles of PEGs, whereas the OH stretching band of water was used as an internal intensity standard. In addition to providing a straightforward approach to measuring diffusion coefficients, the Raman profile analysis provides information relative to the accessibility of gels to large molecules. As an example, it was found that the PEG penetration in Ca-alginate gels was restricted, a phenomenon that was dependent on PEG size. The Raman technique presented here effectively characterizes transport properties of solutes in gels, and such characterization is required for developing several technical applications of gels, such as their use as materials for controlled release of drugs.