In Vivo Simultaneous Analysis of Gene Expression by Dual-Color Luciferases in Caenorhabditis elegans

Both fluorescent and luminescent observation are widely used to examine real-time gene expression patterns in living organisms. Several fluuorescent and luminescent proteins with specific optical properties have been developed and applied for simultaneous, multi-color observation of more than two gene expression profiles. Compared to fluorescent proteins, however, the application of multi-color luminescent imaging in living organisms is still limited. In this study, we introduced two-color luciferases into the soil nematode C. elegans and performed simultaneous analysis of two gene expression profiles. Using a green-emitting luciferase Eluc (emerald luciferase) and red-emitting luciferase SLR (stable luciferase red), the expression patterns of two genes were simultaneously observed in single animals from embryonic to adult stages over its whole life span. In addition, dual gene activities were observed at the single embryo level, with the simultaneous observation of morphological changes. These are the first application of a two-color luciferase system into a whole animal and suggest that precise relationship of expression patterns of multiple genes of interest can be analyzed over the whole life of the animal, dependent on the changes in genetic and/or environmental conditions.     

Tribology of silicon-thin-film-coated SiC ceramics and the effects of high energy ion irradiation

The sliding friction coefficients and specific wear of SiC ceramics coated with a silicon thin film (Si/SiC) with and without subsequent Ar⁺ irradiation against a diamond pin were measured with a pin-on-disk tester at room temperature in laboratory air of approximately 50% relative humidity without oil lubrication for 40 h. The friction coefficient of Ar⁺-irradiated Si/SiC was about 0.05 with a normal load of 9.8 N and remained almost unchanged during the 40 h test, while that of SiC increased from 0.04 to 0.12 during the test. The silicon deposition also reduced the specific wear of SiC to less than one tenth of that of the uncoated SiC. Effectively no wear was detected in Si/SiC irradiated to doses of over2×10¹⁶ions cm⁻².     

Effects of phase changes on reflection and their wavelength dependence in optical profilometry

The method as well as an appropriate instrumentation for measuring phase changes of reflected light is described. The phase changes on samples of Au, Al, Ag, and Cr evaporated films are measured for five wavelengths (lambda) from 442 to 633 nm, with respect to the phase change at the glass-air interface, where it should be zero. The measured results for the Au film are in fairly good agreement with values calculated by use of optical constants from a handbook or the complex refractive index measured by an ellipsometer. The phase changes for Al and Ag films are different from calculated values by ~5 degrees or a shift length of 4.4 nm at lambda = 633 nm, while those of the Cr film show large shifts as high as 16 degrees or a shift length of 9.8 nm at lambda = 442 nm.     

In situ X-ray diffraction of surface oxide on type 430 stainless steel in breakaway condition using synchrotron radiation

Changes in the crystal structure of type 430 stainless steel and the oxides on its surface were studied in situ at 1373 K using a high-intensity synchrotron X-ray source provided by SPring-8 in Japan. The surface of the steel was initially covered with Cr₂O₃, which was then converted to FeCr₂O₄, and finally Fe₃O₄ and Fe₂O₃ formed on it. These results indicated that the reason for the breakaway oxidation in type 430 stainless steel is Cr depletion beneath Cr₂O₃ layer and the subsequent ionisation of Fe, not the simple mechanical failure of Cr₂O₃.     

Gaze direction modulates the disengagement of attention from facial expression in 10-month-olds.

This study investigated whether the disengagement of attention from facial expression is modulated by gaze direction in infants. To this end, we measured the saccadic reaction time required for the 10-month-olds to disengage their attention from angry and happy expressions combined with either straight or averted gaze. The 10-month-olds' disengagement of their attention from happy faces was modulated by gaze direction. This finding indicates that gaze direction strongly influences infants' allocation of attention to facial expressions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Electrochemical insertion and extraction of lithium-ion at nano-sized LiMn2O4 particles prepared by a spray pyrolysis method

Nano-sized LiMn₂O₄ particles were prepared at 1023 K by electrospray pyrolysis in which they were directly deposited on a Pt substrate in gas phase. Cyclic voltammetry gave very sharp and symmetrical redox peaks at ca. 4.0 and 4.1 V vs. Li/Li⁺ owing to the insertion and extraction of lithium-ion at LiMn₂O₄. However, the redox peaks broadened and their peak separation in an electrode potential increased when aggregated nano-sized LiMn₂O₄ particles were used. In Nyquist plots, a semi-circle due to lithium-ion transfer resistance appeared at potentials above 3.90 V. The values of the lithium-ion transfer resistances were small for dispersed nano-sized LiMn₂O₄ particles. On the other hand, the lithium-ion transfer resistances increased and the Warburg impedance became obvious as the nano-sized LiMn₂O₄ particles aggregated. These results clearly indicate that the apparent rapid diffusion of lithium-ion can be attained using well-dispersed nano-sized particles of electroactive materials.     

Preparation and electrochemical properties of SiO2–non-graphitizable carbon composites as negative electrode materials for Li-ion batteries

SiO₂–non-graphitizable carbon composites were prepared by pyrolysis of a mixture of ethyl cellulose and nano-sized SiO₂. The composite electrode showed high reversibility in insertion and/or extraction reactions of Li ions at potentials below 1 V with little hysteresis after the 2nd cycle, whereas a large irreversible capacity was observed in the 1st cycle. This reversible capacity increased with increasing SiO₂ content above 5 wt%. Li ion transfer at the interface between a composite electrode and an electrolyte was studied by ac impedance spectroscopy. In the Nyquist plots, a semi-circle that was assigned to charge-transfer resistance (R _ct) because of Li ion transfer across the interface between the composite electrode and electrolyte appeared at potentials below 1 V. The values of R _ct decreased with increasing SiO₂ content. These results indicate that both a decrease in R _ct and an increase in reversible capacity can be achieved by use of SiO₂–non-graphitizable carbon composite electrodes; this would lead to Li-ion batteries with higher power and energy density.     

Living activity recognition using off-the-shelf sensors on mobile phones

In aging societies, such as that of Japan, there is growing awareness that robotic technology has the potential to help both physical and mental labor. To take an example of mental labor, the robotic technology can contribute as an interface to home electric appliances and a conversation partner with interactive communication. In this case, it is important to recognize the elderly user’s activities for not only watching-over services but also improving the quality of the conversation. We propose a low-throughput recognition method for in-home living activity recognition using only off-the-shelf sensors, namely an accelerometer and a microphone, which are commonly applied in mobile phones. The system can determine whether the user is walking, quiet, or performing a task by acceleration sensing, and then in the latter case, acoustic sensing can be used to classify the nature of the task that the user is performing. We conducted two experiments to confirm the feasibility of the proposed method. As a result of the first experiment, three movement conditions are classified with more than 95?% accuracy by acceleration sensing: walking, quiet, or performing a task. And it classified the nature of the task into brushing teeth, shaving, drying the hair with a hairdryer, flushing the toilet, vacuuming, washing the dishes, and ironing with 75.8?% accuracy by acoustic sensing and improved the accuracy to 85.9?% by training with only the subject’s own data. Moreover, the result of the second experiment shows that it is effective to adopt instance-based recognition which is an additional recognition scheme per each continuous task, according to the assumed application.