Methodology for predicting OEL from rodent LD50 values for metals and metallic compounds

The relationship between the occupational exposure limits (OEL) and the lethal dose 50 (LD50) values of rats or mice for metals and metallic compounds was statistically analyzed by a stepwise multivariate regression method. The OEL values were predicted from LD50 values and metallic compensation coefficients (MCC), which were developed as the regression coefficients of dummy variables that represented the metallic element contained in the substance of interest. The value of the MCC indicated the extent of the adverse health effects of the metal in the substance. Smaller values of the MCC were assigned to metals that would have the more severe adverse health effects, such as carcinogenesis, while larger values were given to the less toxic metals. The Health Index (HI) based on the OEL values was proposed as a convenient measure of the toxicity of industrial products. The prediction method could be applied to toxicity risk assessments by using the HI when a designer of consumer products wants to use substances for which OEL values have not been determined. Two case studies were conducted to estimate the potential toxicity of materials used in solders and in rechargeable batteries.     

CO2-facilitated transport membranes prepared by blending polyvinyl alcohol and various water-absorbing agents

This study describes the production of a membrane by blending polyvinyl alcohol (PVA) and water-absorbing agents for the selective permeation of CO₂ by optimizing the type of water-absorbing agent and its ratio to PVA. A CO₂-facilitated transport membrane is prepared by adding an aqueous cesium carbonate solution to a coated polymer blend matrix. When sodium polyacrylate (PAANa) is blended with PVA as a water-absorbing agent, the resulting membrane shows promising heat and pressure resistances and a relatively high CO₂/He separation performance. Particularly, the CO₂/He selectivity of the membrane composed of PVA, PAANa, and another water-absorbing agent exceeds 400 under a total pressure of 0.1 MPa and a CO₂ partial pressure of 0.08 MPa at 85°C. Moreover, the CO₂/He selectivity is approximately 100 even under a total pressure of 0.7 MPa and a CO₂ partial pressure of 0.56 MPa. Thus, a high-performance CO₂ separation membrane at 85°C is produced.     

Error of Darcy's law for serpentine flow fields: An analytical approach

Serpentine flow fields and other flow fields with partial under-land cross-flow are commonly used in various energy devices, such as proton exchange membrane (PEM) fuel cells and redox flow batteries, due to their higher mass transfer rate to reaction sites and better product removal capability. Accurately predicting the under-land cross-flow rate and pressure drop in such flow fields is crucial in flow field design optimizations. Darcy's law is the most commonly used model in predicting the under-land cross-flow and pressure drop in such flow fields. However, since the Darcy's law neglects inertial effect, its validity in different designs and operating conditions needs to be carefully studied. In this work, mathematical models for a serpentine flow field are developed based on both the Darcy's law and a modified Darcy's law that includes the inertial effect. Both models are solved and analytical solutions are obtained. The predicted pressure drops and under-land cross-flow rates from the two models are compared with experimental data and the results show that under some conditions, both the Darcy's law and the modified Darcy's law can predict pressure drop and under-land cross-flow rate reasonably well. However, under other conditions the Darcy's law can result in significantly large errors in predicting both pressure drop and under-land cross-flow rates. Further studies provide the variations of errors from the Darcy's law with different parameters, including channel length, gas diffusion layer (GDL) thickness, land width, inlet flow rate, GDL permeability and GDL inertial coefficient.     

Efficient Identification of the MYC Regulator with the Use of the CRISPR Library and Context-Matched Database Screenings

MYC is a major oncogene that plays an important role in cell proliferation in human cancers. Therefore, the mechanism behind MYC regulation is a viable therapeutic target for the treatment of cancer. Comprehensive and efficient screening of MYC regulators is needed, and we had previously established a promoter screening system using fluorescent proteins and the CRISPR library. For the efficient identification of candidate genes, a database was used, for which mRNA expression was correlated with MYC using datasets featuring “Similar” and “Not exactly similar” contexts. INTS14 and ERI2 were identified using datasets featuring the “Similar” context group, and INTS14 and ERI2 were capable of enhancing MYC promoter activity. In further database analysis of human cancers, a higher expression of MYC mRNA was observed in the INTS14 mRNA high-expressing prostate and liver cancers. The knockdown of INTS14 in prostate cell lines resulted in decreased MYC mRNA and protein expression and also induced G0/1 arrest. This study confirmed that CRISPR screening combined with context-matched database screening is effective in identifying genes that regulate the MYC promoter. This method can be applied to other genes and is expected to be useful in identifying the regulators of other proto-oncogenes.     

Numerical simulations of gas–liquid–particle three-phase flows using a hybrid method

For the analysis of debris behavior in core disruptive accidents of liquid metal fast reactors, a hybrid computational tool was developed using the discrete element method (DEM) for calculation of solid particle dynamics and a multi-fluid model of a reactor safety analysis code, SIMMER-III, to reasonably simulate transient behavior of three-phase flows of gas–liquid–particle mixtures. A coupling numerical algorithm was developed to combine the DEM and fluid-dynamic calculations, which are based on an explicit and a semi-implicit method, respectively. The developed method was validated based on experiments of water–particle dam break and fluidized bed in systems of gas–liquid–particle flows. Reasonable agreements between the simulation results and experimental data demonstrate the validity of the present method for complicated three-phase flows with large amounts of solid particles.     

Development of multicomponent vaporization/condensation model for a reactor safety analysis code SIMMER-III: Extended verification using multi-bubble condensation experiment

Complex phenomena such as phase transitions and heat transfers in multiphase, multicomponent flows were modeled in the fluid-dynamics portion of SIMMER-III, which was developed to appropriately assess core disruptive accidents (CDAs) in liquid–metal fast reactors (LMFRs). A new multicomponent vaporization/condensation (V/C) model was developed and introduced to SIMMER-III by the authors. In the present study, a new series of multi-bubble condensation experiments was performed to demonstrate that SIMMER-III with the present V/C model is practically applicable to multicomponent, multiphase flow systems with phase transition. In the experiments, bubble diameters and void fractions were quantified from visualization images using original image-processing techniques. Comparing SIMMER-III predictions with experimental data, it was confirmed that SIMMER-III with the proposed V/C model could suitably represent the effects of noncondensable components on the condensation process in multi-bubble systems. This work has improved the reliability of SIMMER-III with regard to multicomponent phase-transition phenomena.     

Identification of major dioxin-like compounds and androgen receptor antagonist in acid-treated tissue extracts of high trophic-level animals

We evaluated the applicability of combining in vitro bioassays with instrument analyses to identify potential endocrine disrupting pollutants in sulfuric acid-treated extracts of liver and/or blubber of high trophic-level animals. Dioxin-like and androgen receptor (AR) antagonistic activities were observed in Baikal seals, common cormorants, raccoon dogs, and finless porpoises by using a panel of rat and human cell-based chemical-activated luciferase gene expression (CALUX) reporter gene bioassays. On the other hand, no activity was detected in estrogen receptor α (ERα)-, glucocorticoid receptor (GR)-, progesterone receptor (PR)-, and peroxisome proliferator-activated receptor γ2 (PPARγ2)-CALUX assays with the sample amount applied. All individual samples (n = 66) showed dioxin-like activity, with values ranging from 21 to 5500 pg CALUX-2,3,7,8-tetrachlorodibenzo-p-dioxin equivalent (TEQ)/g-lipid. Because dioxins are expected to be strong contributors to CALUX-TEQs, the median theoretical contribution of dioxins calculated from the result of chemical analysis to the experimental CALUX-TEQs was estimated to explain up to 130% for all the tested samples (n = 54). Baikal seal extracts (n = 31), but not other extracts, induced AR antagonistic activities that were 8-150 μg CALUX-flutamide equivalent (FluEQ)/g-lipid. p,p'-DDE was identified as an important causative compound for the activity, and its median theoretical contribution to the experimental CALUX-FluEQs was 59% for the tested Baikal seal tissues (n = 25). Our results demonstrate that combining in vitro CALUX assays with instrument analysis is useful for identifying persistent organic pollutant-like compounds in the tissue of wild animals on the basis of in vitro endocrine disruption toxicity.     

Two‐Degree‐of‐Freedom Robust Temperature Control of Peltier Device Based on Heat Disturbance Observer

Recently, the Peltier device has been attracting attention as a haptic device that can transfer heat, because it has relatively fast response characteristics among thermal devices. To transmit thermal sensation, temperature control is considered to be important. However, it is difficult to design a controller because of factors such as parameter variations, nonlinear characteristics of the device, and heat that flows from an external object. Furthermore, it is preferable that the tracking performance and disturbance suppression characteristics be designed independently. To address these factors, this paper proposes a heat disturbance observer, which is constructed by using the disturbance observer commonly used in the field of motion control. When the observer is used, the thermal system becomes robust to the above‐mentioned factors. In addition, it is possible to design the tracking performance independently of the disturbance suppression characteristics. The validity of the proposal is confirmed by experimental results. © 2013 Wiley Periodicals, Inc. Electr Eng Jpn, 184(1): 66–74, 2013; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.22282     

A link selection method for web‐browser using eye‐gaze input

Methods for browsing Web pages using eye‐gaze input have been proposed for severely physically handicapped people who cannot handle a computer mouse to utilize convenient services on the Internet. There are two important functions for Web‐browsers, namely scroll and link selection. Since it is difficult to introduce existing link selection methods using eye‐gaze input for home usage because of high costs or complexity, we propose in this paper a novel link selection method using eye‐gaze input. The proposed method analyzes the HTML source in a Web page and makes a group of links by the content of each. In evaluation experiments, we compare the proposed method with a comparative method using eye‐gaze input with respect to the average response time in selecting the links. The results of the experiments show that the average response is nearly twice as fast as that of the compared method. © 2014 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.