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Structural colors with tunable properties have extensive applications in surface decoration, arts, absorbers, and optical filters. Planar structures have more advantages over other forms studied to date due to their easy manufacturability. Metal-insulator-metal-based structures are one of the known methods to fabricate structural colors where colors can be tuned mainly by the thickness of the intermediate lossless insulator layer. However, generating colors by MIM structure requires a thin metallic layer on top, and the top metals’ abrasiveness and/or oxidation may degrade the colors quickly. Thus, we propose a lossy dielectric layer to replace the top metallic layer as a solution to ensure the structure’s durability by preventing scratches and oxidation. Herein, CrON/Si3N4/Metal structures have been studied where theoretical investigations suggest that highly saturated colors can be generated in the lossy-lossless dielectric structures. Experimental data validated such simulations by revealing a range of vivid colors. Furthermore, these structures can easily achieve strong light absorption (SLA) even for a thick top layer of ∼100 nm. The colors realized by these structures are appeared due to a combination of the interference effect of the asymmetric Fabry–Perot cavity structure and the absorption rate in the CrO x N1−x layer.

In this study, an analytical method was established and validated to determine the preservatives such as dehydroacetic acid, benzoic acid, sorbic acid, methylparaben and ethylparaben. The level of preservatives was measured by solvent extraction method adding purification process with carrez reagent and by high-performance liquid chromatography (HPLC). The developed analytical method was successfully applied to determine the concentration of preservatives in various food samples including jam, cheese and soy sauce, displaying high accuracy (recoveries between 87.8% and 110%) and precision (%RSD less than 5.92% and 7.72% for intra-day and inter-day, respectively). To verify the applicability of the improved test method, selected 13 food items and collected 521 samples were monitored. As a result, all the cases met the Korea standard guidelines. Consequently, this study is expected to contribute to the safety management of preservatives for domestic distribution and imported food.

We report a theoretical investigation of field emission from metals in n-dimension. The field-emission current density is derived as a function of the electric field in one to three dimensions. Then, the generalized field-emission current density is calculated for arbitrary n dimensions, is shown as a function of electric field for different work functions of one-, two- and three-dimensional materials, and is expressed as a function of dimension for different work functions. These analyses reveal that the current density increases as the spatial dimension increases in the conductors and work function decreases. Our study on the generalized current density can be applied to material systems with high dimensions or fractional dimensions.

Randomly distributed plasmonic Ag nanoparticles (NPs) with various sizes were fabricated by a reflow process to an island-shaped Ag thin-film deposited on a Si photodiode. These NPs conformally enclosed by an antireflective (AR)-type SiNx/SiO2 bilayer reveal significantly diminished reflectance in a broad wavelength (500 nm - 1100 nm) as compared to the cases of Ag NPs or SiO2 layer enclosing Ag NPs on the Si substrate. Accordingly, the forward scattering and the total reflection along with wide-angle interference in between the dielectric bilayer incorporating the Ag NPs induce highly increased light absorption in the Si substrate. The fabricated Si photodiode adopting the plasmonic AR bilayer shows the responsivity peak value of 0.72 A/W at 835 nm wavelength and significant responsivity enhancement up to 40% relative to a bare Si photodiode in a wavelength range of 500 nm to 1000 nm.

To realize high-resolution thermal images with high quality, it is essential to improve the noise characteristics of the widely adopted uncooled microbolometers. In this work, we applied the post-metal annealing (PMA) process under the condition of deuterium forming gas, at 10 atm and 300 °C for 30 min, to reduce the noise level of amorphous-Si microbolometers. Here, the DC and temperature coefficient of resistance (TCR) measurements of the devices as well as 1/f noise analysis were performed before and after the PMA treatment, while changing the width of the resistance layer of the microbolometers with 35 μm or 12 μm pixel. As a result, the microbolometers treated by the PMA process show the decrease in resistance by about 60% and the increase in TCR value up to 48.2% at 10 Hz, as compared to the reference device. Moreover, it is observed that the noise characteristics are improved in inverse proportion to the width of the resistance layer. This improvement is attributed to the cured poly-silicon grain boundary through the hydrogen passivation by heat and deuterium atoms applied during the PMA, which leads to the uniform current path inside the pixel.

Thermionic emission for quasi-free electron metals is investigated in arbitrary dimension. The thermionic emission for a constant temperature and work function is calculated for one, two and three dimensions. The generalized current density of the thermionic emission is calculated for arbitrary dimension. The current density is shown as a function of temperature for different work functions. The current density is also shown as a function of dimension for different temperatures and work functions.

In vivo phototoxicity testing is important for predicting drug-induced phototoxicity in humans. Currently, there is no internationally validated in vivo test method for the photosafety evaluation of pharmaceuticals. In this study, we evaluated the phototoxicity of systemically administered drugs using SD rats. We first determined the appropriate ultraviolet A (UVA) dose using 8-methoxypsoralen, a well-known phototoxic drug. Compared to lower and higher UVA doses, we found that a UVA dose of 10 J/cm(2) allowed for the detection of phototoxic responses in both a dose- and time-dependent manner. We next performed a phototoxicity study using seven pharmaceutical drugs which included known phototoxic and non-phototoxic drugs using a UVA dose of 10 J/cm(2). In order to improve the accuracy of our assessment, we evaluated both gross skin findings as well as histopathological findings. Using gross skin findings alone resulted in an accuracy of 85.7% which could be increased to 100% accuracy when the gross skin findings were combined with histopathological findings. This study suggests that the inclusion of histopathological findings increases the accuracy of the phototoxicity evaluation of systemically administered drugs in SD rats. In conclusion, we found that for studying drug-induced phytotoxicity, a 10 J/cm(2) UVA dose serves as the optimal radiation dose, and that the inclusion of histopathological findings increases the accuracy of the phototoxicity evaluation of the drugs.

Human skins are exposed to nanomaterials in everyday life from various sources such as nanomaterial-containing cosmetics, air pollutions, and industrial nanomaterials. Nanomaterials comprising metal haptens raises concerns about the skin sensitization to nanomaterials. In this study, we evaluated the skin sensitization of nanomaterials comparing metal haptens in vivo and in vitro. We selected five metal oxide NPs, containing copper oxide, cobalt monoxide, cobalt oxide, nickel oxide, or titanium oxide, and two types of metal chlorides (CoCl2 and CuCl2), to compare the skin sensitization abilities between NPs and the constituent metals. The materials were applied to KeratinoSensTM cells for imitated skin-environment setting, and luciferase induction and cytotoxicity were evaluated at 48 h post-incubation. In addition, the response of metal oxide NPs was confirmed in lymph node of BALB/C mice via an in vivo method. The results showed that CuO and CoO NPs induce a similar pattern of positive luciferase induction and cytotoxicity compared to the respective metal chlorides; Co3O4, NiO, and TiO2 induced no such response. Collectively, the results implied fast-dissolving metal oxide (CuO and CoO) NPs release their metal ion, inducing skin sensitization. However, further investigations are required to elucidate the mechanism underlying NP-induced skin sensitization. Based on ion chelation data, metal ion release was confirmed as the major “factor” for skin sensitization.

High crystalline ZnO nanorods (NRs) on Zn pre-deposited graphene/Cu sheet without graphene transfer process have been fabricated by self-catalyzed vapor-phase transport synthesis. Here, the pre-deposited Zn metal on graphene not only serves as a seed to grow the ZnO NRs, but also passivates the graphene underneath. The temperature-dependent photoluminescence spectra of the fabricated ZnO NRs reveal a dominant peak of 3.88 eV at 10 K associated with the neutral-donor bound exciton, while the redshifted peak by bandgap shrinkage with temperature and electron-lattice interactions leads a strong emission at 382 nm at room temperature. The optical absorption of the ZnO NRs/graphene hetero-nanostructure at this ultraviolet (UV) emission is then theoretically analyzed to quantify the absorption amount depending on the ZnO NR distribution. By simply covering the ZnO NR/graphene/Cu structure with the graphene/glass as a top electrode, it is observed that the current-voltage characteristic of the ZnO NR/graphene hetero-nanojunction device exhibits a photocurrent of 1.03 mA at 3 V under a light illumination of 100 μW/cm2. In particular, the suggested graphene/ZnO NRs/graphene hybrid-nanostructure-based devices reveal comparable photocurrents at a bidirectional bias, which can be a promising platform to integrate 1D and 2D nanomaterials without complex patterning process for UV device applications.

Some drugs cause phototoxicity in humans when exposed to light, thus there is a need for an in vivo phototoxicity test to evaluate them. However, an in vivo phototoxicity test method to evaluate this has not been established. This study aimed to establish an in vivo phototoxicity test method for transdermally administered drugs. For this, we evaluated the phototoxicity using Sprague-Dawley (SD) rats for transdermal administered drugs and we studied the appropriate UVA dose using 8-methoxypsalen, which is a well-known phototoxic drug. We found that a UVA dose of 15 J/cm2 was dose and time dependent response compared to other UVA doses. We performed the Minimum Erythema Dose (MED) test because UVB can cause skin irritation by itself and selected 0.01 J/cm2 as an appropriate dose of UVB. Using the selected UVA and UVB doses, we performed a phototoxicity study of 6 pharmaceutical drugs, which included phototoxic and non-phototoxic drugs. As a result of the phototoxicity test, 100% accuracy was obtained when compared with previous studies. In addition, we performed histopathology to confirm the new findings. We found that histopathology can be used as an additional indicator of phototoxicity test for transdermally administered drugs.

The compound 6:2 chlorinated polyfluorinated ether sulfonate (F-53B), a replacement for perfluorooctanesulfonate (PFOS) in the electroplating industry, has been widely detected in numerous environmental matrices, human sera, and organisms. Due to regulations that limit PFOS use, F-53B use is expected to increase. Therefore, in this study, we performed a subchronic oral toxicity study of F-53B in Sprague Dawley (SD) rats. F-53B was administered orally once daily to male and female rats for 28 days at doses of 5, 20, and 100 mg/kg/day. There were no toxicologically significant changes in F-53B-treated rats, except in the thyroid gland. However, F-53B slightly reduced the serum concentrations of thyroid hormones, including triiodothyronine and thyroxine, compared with their concentrations in the vehicle group. F-53B also induced follicular hyperplasia and was associated with increased thyroid hormone biosynthesis-associated protein expression. These results demonstrate that F-53B is a strong regulator of thyroid hormones in SD rats as it disrupts thyroid function. Thus, caution should be exercised in the industrial application of F-53B as an alternative for PFOS.

Numerous studies have reported the potential of chemicals for inducing skin sensitization; however, few studies have examined skin sensitization induced by nanomaterials. This study aimed to evaluate skin sensitization induced by metal oxide nanoparticles (NPs) using the ARE-Nrf2 Luciferase KeratinoSens™ assay. Seven different metal oxide NPs, including copper oxide, cobalt oxide, nickel oxide, titanium oxide, cerium oxide, iron oxide, and zinc oxide, were assessed on KeratinoSens™ cells. We selected an appropriate vehicle among three vehicles (DMSO, DW, and culture medium) by assessing the hydrodynamic size at vehicle selection process. Seven metal oxide NPs were analyzed, and their physicochemical properties, including hydrodynamic size, polydispersity, and zeta potential, were determined in the selected vehicle. Thereafter, we assessed the sensitization potential of the NPs using the ARE-Nrf2 Luciferase KeratinoSens™ assay. Copper oxide NPs induced a positive response, whereas cobalt oxide, nickel oxide, titanium oxide, cerium oxide, iron oxide, and zinc oxide NPs induced no response. These results suggest that the ARE-Nrf2 Luciferase KeratinoSens™ assay may be useful for evaluating the potential for skin sensitization induced by metal oxide NPs.

Although skin sensitization potential of various chemicals has been extensively studied, there are only a few reports on nanoparticles induced skin sensitization. Aiming to fill this lacuna, in this study we evaluated the potential of metal oxide nanoparticles (NPs) to induce skin sensitization with flow cytometry. Seven different metal oxide NPs, including copper oxide, cobalt oxide, nickel oxide, titanium oxide, cerium oxide, iron oxide, and zinc oxide were applied to Balb/c mice. After selecting the proper vehicle, the NPs were applied, and the skin sensitization potential were assessed using 5-bromo-2-deoxyuridine with flow cytometry. Physiochemical properties such as hydrodynamic size, polydispersity, and zeta potential were measured for the NPs prior to the tests. All the seven metal oxide NPs studied showed negative responses for skin sensitization potential. These results suggest that the OECD TG 442B using 5-bromo-2-deoxyuridine with flow cytometry can be applied to evaluate the potential of NPs for skin sensitization.

Zinc oxide nanoparticles (ZnO NPs) are used in various industries such as food additives, cosmetics, and biomedical applications. In this study, we evaluated lung damage over time by three types of ZnO NPs (L-serine, citrate, and pristine) following the regulation of functional groups after a single intratracheal instillation to rats. The three types of ZnO NPs showed an acute inflammatory reaction with increased LDH and inflammatory cell infiltration in the alveoli 24 h after administration. Especially in treatment with L-serine, citrate ZnO NPs showed higher acute granulocytic inflammation and total protein induction than the pristine ZnO NPs at 24 h. The acute inflammatory reaction of the lungs recovered on day 30 with bronchoalveolar fibrosis. The concentrations of IL-4, 6, TNF-α, and eotaxin in the bronchoalveolar lavage fluid (BALF) decreased over time, and the levels of these inflammation indicators are consistent with the following inflammatory cell data and acute lung inflammation by ZnO NP. This study suggests that single inhalation exposure to functionalized ZnO NPs may cause acute lung injury with granulocytic inflammation. Although it can recover 30 days after exposure, acute pulmonary inflammation in surface functionalization means that additional studies of exposure limits are needed to protect the workers that produce it.

Skin sensitisation is the regulatory endpoint that has been at the centre of concerted efforts to replace animal testing in recent years, as demonstrated by the Organisation for Economic Co-operation and Development (OECD) adoption of five non-animal methods addressing mechanisms under the first three key events of the skin sensitisation adverse outcome pathway. Nevertheless, the currently adopted methods, when used in isolation, are not sufficient to fulfil regulatory requirements on the skin sensitisation potential and potency of chemicals comparable to that provided by the regulatory animal tests. For this reason, a number of defined approaches integrating data from these methods with other relevant information have been proposed and documented by the OECD. With the aim to further enhance regulatory consideration and adoption of defined approaches, the European Union Reference Laboratory for Alternatives to Animal testing in collaboration with the International Cooperation on Alternative Test Methods hosted, on 4-5 October 2016, a workshop on the international regulatory applicability and acceptance of alternative non-animal approaches, i.e., defined approaches, to skin sensitisation assessment of chemicals used in a variety of sectors. The workshop convened representatives from more than 20 regulatory authorities from the European Union, United States, Canada, Japan, South Korea, Brazil and China. There was a general consensus among the workshop participants that to maximise global regulatory acceptance of data generated with defined approaches, international harmonisation and standardisation are needed. Potential assessment criteria were defined for a systematic evaluation of existing defined approaches that would facilitate their translation into international standards, e.g., into a performance-based Test Guideline. Informed by the discussions at the workshop, the ICATM members propose practical ways to further promote the regulatory use and facilitate adoption of defined approaches for skin sensitisation assessments.

Although alternative test methods based on the 3Rs (Replacement, Reduction, Refinement) are being developed to replace animal testing in reproductive and developmental toxicology, they are still in an early stage. Consequently, we aimed to develop alternative test methods in male animals using mouse spermatogonial stem cells (mSSCs). Here, we modified the OECD TG 489 and optimized the in vitro comet assay in our previous study. This study aimed to verify the validity of in vitro tests involving mSSCs by comparing their results with those of in vivo tests using C57BL/6 mice by gavage. We selected hydroxyurea (HU), which is known to chemically induce male reproductive toxicity. The 50% inhibitory concentration (IC50) value of HU was 0.9 mM, as determined by the MTT assay. In the in vitro comet assay, % tail DNA and Olive tail moment (OTM) after HU administration increased significantly, compared to the control. Annexin V, PI staining and TUNEL assays showed that HU caused apoptosis in mSSCs. In order to compare in vitro tests with in vivo tests, the same substances were administered to male C57BL/6 mice. Reproductive toxicity was observed at 25, 50, 100, and 200 mg/kg/day as measured by clinical measures of reduction in sperm motility and testicular weight. The comet assay, DCFH-DA assay, H&E staining, and TUNEL assay were also performed. The results of the test with C57BL/6 mice were similar to those with mSSCs for HU treatment. Finally, linear regression analysis showed a strong positive correlation between results of in vitro tests and those of in vivo. In conclusion, the present study is the first to demonstrate the effect of HU-induced DNA damage, ROS formation, and apoptosis in mSSCs. Further, the results of the current study suggest that mSSCs could be a useful model to predict male reproductive toxicity.

Mo-V-P-O y /Al 2 O 3 (denoted as 18.1Mo1.9VXP/Al: 18.1 wt% Mo, 1.9 wt% V, X wt% P) catalysts with different phosphorus content were prepared by an impregnation method, and they were applied to the acrylonitrile production by ammoxidation of propane. The effect of phosphorus content on the physicochemical properties and catalytic activities was investigated. Conversion of propane and yield for acrylonitrile showed volcano-shaped trends with respect to phosphorus content. Yield for acrylonitrile increased with decreasing binding energy of Mo 3d 5/2 . Among the catalysts, 18.1Mo1.9V0.6P/Al with the smallest binding energy of Mo 3d 5/2 showed the best catalytic performance in the ammoxidation of propane to acrylonitrile.

A graphene-InGaN Schottky junction has been successfully fabricated by transferring graphene layers onto n-type In0.23Ga0.77N/GaN/Al2O3 substrates. Current–voltage (I–V) measurement across the junction demonstrates the rectifying behaviour. Temperature dependent I–V characteristics in a range of 10 K to 300 K reveal that the charge transport mechanism is dominated by thermionic emission. Also, it is observed that the charge-transfer induced variation of Fermi energy of graphene affects the flow of current. This graphene/InGaN junction shows electroluminescence (EL) characteristics under a forward bias, producing bright blue emission (430 nm) at room temperature. As the temperature increases, the EL peak is shifted to a lower energy with a reduced peak intensity due to the increased nonradiative recombination rate. The dependence of EL intensity on the current of the graphene/InGaN junction confirms the band-to-band recombination mechanism in the InGaN layer by the bimolecular radiative recombination. Therefore, the observed results provide an insight for implementing graphene based Schottky-junction devices with tunable emission by utilizing the variable bandgap of the InGaN layer.

We have investigated the effect of light leakage between the adjacent pixels on the electroluminescence (EL) intensity variation in a color filter (CF) stacked white organic light-emitting diode (OLED) display. It is found that light leakage of the white pixel adjacent to the emitting green pixel is the highest level, due to the shortened optical path and high transmittance of the white-CF layer. As the optical path between the adjacent pixels decreases, light-leakage induced EL intensity of the white or blue pixel increases, while there is no appreciable change in the EL intensity of the emitting green pixel. Also, the observed light leakage and the corresponding power spectrum highly increase as the orientation of emitted dipole sources is perpendicular to the interfaces of the layered structures. Therefore, the presented analysis of the light leakage in the CF stacked white OLED provides useful guidelines to improve the device performance for high-resolution OLED displays.

Titanium dioxide nanoparticles (TiO2-NPs) are used to improve the aesthetic of toothpaste. While TiO2-NPs have been used safely in toothpaste products for a long time, there haven't been studies to determine whether absorption of TiO2-NPs by the mucous membranes in the mouth induces pathogenic conditions. Here, we assessed whether TiO2-NPs induce cyclooxygenase-2 (COX-2) and investigated the molecular mechanisms underlying the pro-inflammatory effect of TiO2-NPs on human periodontal ligament (PDL) cells. Treatment of PDL cells with TiO2-NPs led to induction of both COX-2 mRNA and protein expression. TiO2-NPs stimulated the nuclear translocation of nuclear factor-kappaB (NF-κB) as well as its DNA binding by inducing phosphorylation and subsequent degradation of the inhibitory protein IκBα in PDL cells. TiO2-NPs treatment resulted in rapid activation of extracellular signal-regulated kinase (ERK)1/2 and Akt, which could be upstream of NF-κB. Treatment of PDL cells with both the MEK1/2 inhibitor U0126 and the PI3K inhibitor LY294002 strongly attenuated TiO2-NPs-induced activation of NF-κB, and also the expression of COX-2. PDL cells treated with TiO2-NPs exhibited increased accumulation of intracellular reactive oxygen species (ROS). Pretreatment of cells with ROS scavenger N-acetyl cysteine (NAC) abrogated the stimulatory effect of TiO2-NPs on p65, p50, and COX-2 expression. In conclusion, ROS, concomitantly overproduced by TiO2-NPs, induce COX-2 expression through activation of NF-κB signaling, which may contribute to the inflammatory effect of PDL cells.

Carbon nanotubes (CNTs) are one of the major types of nanomaterials that have various industrial and biomedical applications. However, there is a risk of accidental exposure to CNTs in individuals involved in their large-scale production and in individuals who use products containing CNTs. This study aimed to evaluate the skin sensitization induced by CNTs using two alternative tests. We selected single-wall carbon nanotubes and multi-walled carbon nanotubes for this study. First, the physiochemical properties of the CNTs were measured, including the morphology, size, and zeta potential, under various conditions. Thereafter, we assessed the sensitization potential of the CNTs using the ARE-Nrf2 Luciferase KeratinoSens&trade, assay, an in vitro alternative test method. In addition, the CNTs were evaluated for their skin sensitization potential using the LLNA: BrdU-FCM in vivo alternative test method. In this study, we report for the first time the sensitization results of CNTs using the KeratinoSens&trade, and LLNA: BrdU-FCM test methods in this study. This study found that both CNTs do not induce skin sensitization. These results suggest that the KeratinoSens&trade, and LLNA: BrdU-FCM assay may be useful as alternative assays for evaluating the potential of some nanomaterials that can induce skin sensitization.

A series of bimetallic Pd–Fe catalysts supported on ordered mesoporous carbon (denoted as Pd1–FeX/OMC) were prepared with a variation Fe/Pd molar ratio (X), and they were applied to the catalytic decomposition of phenethyl phenyl ether to aromatics. Phenethyl phenyl ether was used as a lignin model compound for representing β-O-4 linkage in lignin. The effect of Fe/Pd molar ratio on the catalytic activities and physicochemical properties of bimetallic Pd1–FeX/OMC catalysts was investigated. It was found that crystalline phase, reducibility, chemical state, and electronic property of Pd1–FeX/OMC catalysts were strongly influenced by Fe/Pd molar ratio. In particular, modified electronic property derived from the interaction between Pd and Fe significantly changed the hydrogen adsorption ability and bimetallic structure of the catalysts. Conversion of phenethyl phenyl ether continuously decreased with increasing Fe/Pd molar ratio, whereas selectivity for aromatics increased and then became almost constant with increasing Fe/Pd molar ratio. As a consequence, yield for aromatics showed a volcano-shaped trend with respect to Fe/Pd molar ratio. Catalytic performance of Pd1–FeX/OMC catalysts was closely related to the hydrogen adsorption ability and bimetallic structure of the catalysts. Among the catalysts tested, Pd1–Fe0.7/OMC catalyst with moderate hydrogen adsorption ability and with bimetallic structure of Pd1Fe0.7 composition showed the highest yield for aromatics. Thus, an optimal Fe/Pd molar ratio was required to achieve maximum production of aromatics through selective cleavage of C O bond in phenethyl phenyl ether over Pd1–FeX/OMC catalysts.

Skin sensitization test data are required or considered by chemical regulation authorities around the world. These data are used to develop product hazard labeling for the protection of consumers or workers and to assess risks from exposure to skin-sensitizing chemicals. To identify opportunities for regulatory uses of non-animal replacements for skin sensitization tests, the needs and uses for skin sensitization test data must first be clarified. Thus, we reviewed skin sensitization testing requirements for seven countries or regions that are represented in the International Cooperation on Alternative Test Methods (ICATM). We noted the type of skin sensitization data required for each chemical sector and whether these data were used in a hazard classification, potency classification, or risk assessment context; the preferred tests; and whether alternative non-animal tests were acceptable. An understanding of national and regional regulatory requirements for skin sensitization testing will inform the development of ICATM's international strategy for the acceptance and implementation of non-animal alternatives to assess the health hazards and risks associated with potential skin sensitizers.

Nanotechnology has advanced at an extremely rapid pace over the past several years in numerous fields of research. However, the uptake of nanoparticles (NPs) into the body after administration through various routes may pose a risk to human health. In this study, we investigated the potential ocular toxicity of 20-nm, negatively- charged zinc oxide (ZnO) NPs in rats using micro-computed tomography (micro-CT) and histopathological assessment. Animals were divided into four groups as control group, ZnO NPs treatment group (500 mg/kg/day), control recovery group, and ZnO NPs treatment and recovery group. Ocular samples were prepared from animals treated for 90 days (10 males and 10 females, respectively) and from recovery animals (5 males and 5 females, respectively) sacrificed at 14 days after final treatment and were compared to age-matched control animals. Micro-CT analyses represented the deposition and distribution of foreign materials in the eyes of rats treated with ZnO NPs, whereas control animals showed no such findings. X-ray fluorescence spectrometry and energy dispersive spectrometry showed the intraocular foreign materials as zinc in treated rats, whereas control animals showed no zinc signal. Histopathological examination revealed the retinopathy in the eyes of rats treated with ZnO NPs. Neuronal nuclei expression was decreased in neurons of the ganglion cell layer of animals treated with ZnO NPs compared to the control group. Taken together, treatment with 20-nm, negatively-charged ZnO NPs increased retinopathy, associated with local distribution of them in ocular lesions.

Bimetallic Pd–Fe catalyst supported on ordered mesoporous carbon (Pd–Fe/OMC) was prepared by a surfactant-templating method and a subsequent incipient wetness impregnation method. The catalyst was applied to the catalytic cleavage of C O bond in benzyl phenyl ether to aromatics. For comparison, monometallic Pd/OMC and Fe/OMC catalysts were also investigated. Benzyl phenyl ether was used as a lignin model compound for representing α-O-4 linkage in lignin. The combined effect of palladium and iron on the physicochemical properties and catalytic activities of Pd–Fe/OMC was investigated. Although Pd/OMC catalyst showed the highest conversion of benzyl phenyl ether, selectivity for aromatics was low due to saturation of aromatic ring. On the other hand, Fe/OMC catalyst showed lower conversion of benzyl phenyl ether than Pd/OMC, but Fe/OMC catalyst showed higher C O bond cleavage selectivity than Pd/OMC catalyst without saturation of aromatics. Bimetallic Pd–Fe/OMC catalyst showed the highest yield for aromatics. The introduction of Fe into Pd/OMC catalyst resulted in the modification of electronic properties of Pd by electron transfer from Fe to Pd, which led to the enhanced yield for aromatics.

Mono-transition metal (Mo, V, and Nb)-substituted Wells–Dawson tungstoarsenates were investigated to elucidate the effect of metal-substitution on their redox behaviors. In the electrochemical analysis, an additional redox transition was observed for molybdenum- and vanadium-substituted tungstoarsenates, while a negatively shifted redox transition was observed for niobium-substituted tungstoarsenate. First electron reduction potential of the catalysts showed the consistent trend with UV–visible absorption edge energy of the catalysts. Oxidative dehydrogenation of benzylamine to dibenzylimine was carried out as a model reaction to probe oxidation catalysis. Yield for dibenzylimine increased with increasing first electron reduction potential and with decreasing UV–visible absorption edge energy.

Jeong-A Lee,1,* Mi-Kyung Kim,1,* Hyoung-Mi Kim,2,* Jong Kwon Lee,3 Jayoung Jeong,4 Young-Rok Kim,5 Jae-Min Oh,2 Soo-Jin Choi1 1Department of Food Science and Technology, Seoul Women’s University, Seoul, Republic of Korea; 2Department of Chemistry and Medical Chemistry, College of Science and Technology, Yonsei University, Wonju, Republic of Korea; 3Hazard Substances Analysis Division, Gwangju Regional Food and Drug Administration, Ministry of Food and Drug Safety, Gwangju, Republic of Korea; 4Toxicological Research Division, National Institute of Food and Drug Safety Evaluation, Ministry of Food and Drug Safety, Chungcheongbuk-do, Republic of Korea; 5Department of Food Science and Biotechnology, Kyung Hee University, Yongin, Republic of Korea *These authors contributed equally to this work Background: Orally administered particles rapidly interact with biological fluids containing proteins, enzymes, electrolytes, and other biomolecules to eventually form particles covered by a corona, and this corona potentially affects particle uptake, fate, absorption, distribution, and elimination in vivo. This study explored relationships between the biological interactions of calcium carbonate particles and their biokinetics.Methods: We examined the effects of food grade calcium carbonates of different particle size (nano [N-Cal] and bulk [B-Cal]: specific surface areas of 15.8 and 0.83 m2/g, respectively) on biological interactions in in vitro simulated physiological fluids, ex vivo biofluids, and in vivo in gastrointestinal fluid. Moreover, absorption and tissue distribution of calcium carbonates were evaluated following a single dose oral administration to rats.Results: N-Cal interacted more with biomatrices than bulk materials in vitro and ex vivo, as evidenced by high fluorescence quenching ratios, but it did not interact more actively with biomatrices in vivo. Analysis of coronas revealed that immunoglobulin, apolipoprotein, thrombin, and fibrinogen, were the major corona proteins, regardless of particle size. A biokinetic study revealed that orally delivered N-Cal was more rapidly absorbed into the blood stream than B-Cal, but no significant differences were observed between the two in terms of absorption efficiencies or tissue distributions. Both calcium carbonates were primarily present as particulate forms in gastrointestinal fluids but enter the circulatory system in dissolved Ca2+, although both types showed partial phase transformation to dicalcium phosphate dihydrate. Relatively low dissolution (about 4%), no remarkable protein–particle interaction, and the major particulate fate of calcium carbonate in vivo gastrointestinal fluids can explain its low oral absorption (about 4%) regardless of particle size.Conclusion: We conclude that calcium carbonate nanoparticles can act more actively with biological matrices in vitro and ex vivo, but that in vivo, their biological interactions and biokinetics are not affected by particle size. Keywords: biological interaction, oral absorption, biokinetics, size effect, protein corona

A series of Re–Ru bimetallic catalysts supported on mesoporous carbon (denoted as (0.6 − x)Re–xRu/MC) were prepared by a single-step surfactant-templating method and a subsequent incipient wetness impregnation method with a variation of ruthenium loading (x, mol%), and they were applied to the liquid-phase hydrogenation of succinic acid to 1,4-butanediol (BDO). The effect of metal content on the catalytic activities and physicochemical properties of (0.6 − x)Re–xRu/MC catalysts was investigated. It was found that a Re–Ru miscible phase was formed in the catalysts during the reduction process, and it was responsible for strong interaction between rhenium and ruthenium. It was also revealed that reducibility, metal dispersion, and oxidation state of (0.6 − x)Re–xRu/MC catalysts were affected by Re:Ru molar ratio. In particular, the oxidation state was closely related to the hydrogen adsorption behavior of the catalysts. The amount of weak hydrogen-binding sites increased with increasing the ratios of metallic rhenium (Re0) and ruthenium (Ru0) with respect to total metallic species in the reduced (0.6 − x)Re–xRu/MC catalysts. Catalytic performance in the hydrogenation of succinic acid to BDO over (0.6 − x)Re–xRu/MC showed a volcano-shaped trend with respect to Re:Ru molar ratio. This result was well correlated with the amount of weak hydrogen-binding sites of the catalysts. Among the catalysts tested, 0.3Re–0.3Ru/MC with the largest amount of weak hydrogen-binding sites showed the best catalytic performance in the BDO production by hydrogenation of succinic acid.

Graphene was grown on a Cu film, processed by annealing and mechanical polishing. The sheet resistance of graphene shows ∼57% decrease by mechanical polishing for raw Cu and ∼20% decrease by annealing for 50 nm SiO2 polishing.

After global financial crisis, the ratio of household debt to GDP was decreasing in other advanced countries such as the U.S., and the U.K. and so on. But, in Korea, household debt (of which residential mortgage loan account for a large part) ratio is still increasing. This paper focuses on the scale and characteristics of households in negative housing equity (those are called House-poors in Korea), and also the socio-economic backgrounds of the formation process. In financial perspective, the problem of negative housing equity depends on financial debt repayment capability. We used DSR (Debt Service Ratio) and LTA (Loan to Asset ratio) as financial indicators to evaluate the debt repayment capability. The critical value of DSR is assumed as 40%, and LTA 100%. The socio-economic backgrounds of the House-poors are as follows : increasing households debt dependency, over lending competition of financial institutions and unreasonable loan in household economy, instability of real estate market, week regulation on mortgage loan. Finally, this paper suggests some implications about the range and the target of public intervention.Key words: Negative Housing Equity, Financial Debt Repayment Capability, DSR(Debt Service Ratio), LTA(Loan to Asset), Mortgage LoanLHI Journal (2014) 5(4):259-269 http://dx.doi.org/10.5804/LHIJ.2014.5.4.259http://lhi.lh.or.kr

Introduction A variety of in vitro tests to replace the Draize test have been developed; however, there is no available method for assessing the full spectrum of Globally Harmonized System (GHS) categories. Human cornea-like three-dimensional (3D) reconstructed tissue models are the most promising in vitro systems. The objective of this study was to evaluate the ocular toxicity of 11 test substances using the EpiOcular™ model after performing proficiency tests. We further evaluated the effectiveness of ezrin staining as a complementary marker in histological analysis to overcome the limitation of eye irritation tests using 3D reconstructed human corneal epithelium models. Methods The assessment of ocular toxicity was performed by the suggested OECD TG 492 procedure. After treatment with proficiency test chemicals and 10 test substances, EpiOcular™ tissue models were stained with hematoxylin and eosin and ezrin, and the histological changes were observed by immunofluorescence microscopy. Results The ocular toxicity assessment of 10 test chemicals using the EpiOcular™ eye irritation test were in accordance with the UN GHS classification of test chemicals. Histological analysis of ezrin staining showed that the cell membranes of models treated with 10 out of 11 non-irritant chemicals were maintained, whereas those of models treated with 14 eye irritant substances resulted in the apparent translocation of ezrins from the cell membrane to the cytoplasm or nucleus by destruction of cell membrane. Discussion Ezrin may be used as a complementary marker to more accurately assess ocular toxicity using 3D reconstructed human cornea-like epithelium models.

This study investigated the changes in depression trajectories and discovered related risk factors affecting these changes among the elderly by gender. Data were obtained subsample who participated in Korean Longitudinal Study of Ageing (KLoSA) from 2006 to 2012. A total of 3,667 individuals (1,566 men and 2,101 women) aged 60 or more were included in the analysis. We used a group-based trajectory model in order to determine the appropriate number of groups and observe the change in the depression according to research year. After trajectory analysis, multinomial regression analysis was performed to examine depression-related risk factors influencing different trajectory group membership. Distinctive differences in the depression trajectories were found; four groups (normal-melancholic-worsening-depressed) in men and five groups (normal-melancholic-worsening-improved-depressed) in women. Chronic diseases, self-rated health (SRH), and somatic pain were associated with depression in both gender. Statistically significant differences were observed in employment among older men, and social integration among older women. In conclusion, maintaining physical health status play an important role in preventing depression. In addition, gender differences were found that employment in men and social integration in women showed beneficial effect on prevention of depression.

Micro-fabricated single-layer graphenes (SLGs) on a silicon dioxide (SiO2)/Si substrate, a silicon nitride (SiN) membrane, and a suspended architecture are presented for their use as temperature sensors. These graphene temperature sensors act as resistance temperature detectors, showing a quadratic dependence of resistance on the temperature in a range between 283 K and 303 K. The observed resistance change of the graphene temperature sensors are explained by the temperature dependent electron mobility relationship (~T−4) and electron-phonon scattering. By analyzing the transient response of the SLG temperature sensors on different substrates, it is found that the graphene sensor on the SiN membrane shows the highest sensitivity due to low thermal mass, while the sensor on SiO2/Si reveals the lowest one. Also, the graphene on the SiN membrane reveals not only the fastest response, but also better mechanical stability compared to the suspended graphene sensor. Therefore, the presented results show that the temperature sensors based on SLG with an extremely low thermal mass can be used in various applications requiring high sensitivity and fast operation.

A series of nickel catalysts supported on mesoporous phosphorus-modified alumina xerogel (Ni/XPA, X = P/Al molar ratio) were prepared by an epoxide-driven sol–gel method and a subsequent incipient impregnation method, and they were applied to the hydrogen production by steam reforming of simulated liquefied natural gas (LNG). All the calcined phosphorus-modified alumina xerogel supports (XPA, X = P/Al molar ratio) retained a mesoporous structure with amorphous crystalline phase. The amount of penta-coordinated aluminum species increased with increasing X (P/Al molar ratio) of XPA supports. Although the calcined Ni/XPA catalysts retained both nickel oxide phase and nickel aluminate phase, relative distribution of nickel species of the catalysts was different depending on X (P/Al molar ratio). Among the catalysts, Ni/0.05PA catalyst showed the highest binding energy of nickel species. Crystallite size of metallic nickel increased with increasing X (P/Al molar ratio) in the reduced Ni/XPA catalysts. However, Ni/0.05PA catalyst showed the largest amount of strong hydrogen-binding sites and exhibited the largest amount of adsorbed methane in the H2-TPD and CH4-TPD measurements, respectively. Catalytic performance in the steam reforming of LNG over Ni/XPA catalysts showed a volcano-shaped trend with respect to X (P/Al molar ratio). This result was well correlated with the amount of adsorbed methane calculated from CH4-TPD measurements. Among the catalysts tested, Ni/0.05PA catalyst with the highest affinity toward methane showed the best catalytic performance in hydrogen production by steam reforming of LNG.