Decoding of depth and motion in ambiguous binocular perception

We have shown previously that random dots with an interocular time delay (ITD), the time difference of the onset of dots between the two eyes, yield both apparent depth and motion, although depth and velocity are covariant and, thus, ITD is inherently ambiguous. The depth of random dots with ITD was proportional to ITD, suggesting that the visual system assumes a constant velocity of the dots and determines depth on the basis of this constant velocity. We performed psychophysical experiments to investigate whether subjects perceive a constant velocity with a variety of ITDs in random dots aligned along a single vertical line that ensures neither apparent motion nor accidental disparity between the dots. The results showed that subjects perceive a constant velocity for a variety of ITDs with simultaneous perception of depth in proportion to ITD, indicating the priority of depth over velocity in ambiguous binocular perception derived from ITD.     

High electrical performance of carbon nanotubes/rubber composites with low percolation threshold prepared with a rotation-revolution mixing technique

The present study demonstrates a novel mixing approach for achieving a good dispersion of carbon nanotubes (CNTs) in a styrene-butadiene rubber (SBR), which leads to a significant improvement in electrical properties. Our mixing technique consists of (1) pretreatment by ultrasonication to disentangle the bundles of CNTs in organic solvent and (2) “rotation-revolution” mixing of the CNTs with SBR without mechanical shear, which prevents CNTs from collapsing during the mixing process. The present mixing method does not require the addition of any dispersing agents (amphiphilic molecules) or chemical modification of the CNTs to obtain a good dispersion. Compared with a conventional Banbury mixing technique, our method leads to a significant decrease in the percolation threshold (less than 1 phr), where the electrical conductivity suddenly increases due to the formation of percolation networks of CNTs in SBR. This is because the aspect ratio of the CNTs was maintained even after the mixing process, whereas CNTs were broken during the conventional Banbury mixing. The effect of using different types of CNTs on electrical conductivity was also investigated. The results show that the percolation threshold is largely related to the structural quality (graphitization) of the CNTs as well as their aspect ratio.     

Cytotoxicity evaluation of reactive metabolites using rat liver homogenate microsome-encapsulated alginate gel microbeads

We present an improved cytotoxicity test for reactive metabolites, in which the S9 microsomal fraction of rat liver homogenate is encapsulated in alginate gel microbeads to avoid cytotoxic effects of S9-self-generated toxicants, microsomal lipid peroxides. The S9-encapsulated gel microbeads were prepared by a coaxial two-fluid nozzle and surfaces of the microbeads were coated with poly-L-lysine (PLL). Although the initial metabolic rate of the S9-encapsulated gel microbeads was about 20% slower than that of bare S9, the microbeads prevented the leakage of microsomal lipid peroxides thanks to the dense alginate and PLL polymer networks. In fact, the half maximal effective concentration of the indirect mutagen cyclophosphamide on NIH3T3 cells in the presence of the S9-encapsulated gel microbeads was about 5 times higher than that in the presence of bare S9. Use of the S9-encapsulated gel microbeads enabled the more accurate evaluation of the cytotoxicity of the reactive metabolites without the S9-based cytotoxicity.     

Determination of pindone in animal products, fishery products, and honey by LC-MS/MS

A sensitive and selective analytical method for the determination of the rodenticide pindone in animal products, fishery products, and honey by LC-MS/MS was developed. Pindone was extracted with acidified acetone, and the crude extract was purified by liquid-liquid partitioning, followed by silica gel and ODS column chromatography. LC separation was performed on an ODS column with methanol/water containing ammonium acetate as the mobile phase, and detection was carried out using tandem mass spectrometry (MS/MS) with electrospray ionization (ESI) in the negative mode. The average recoveries from fortified bovine muscle, bovine liver, bovine fat, chicken muscle, salmon, eel, freshwater clam, egg, milk, and honey spiked at 0.001 mg/kg were in the range of 76-92%, and the relative standard deviations were 4-8%. The limit of quantitation (S/N≥10) of the developed method was 0.001 mg/kg for all the tested foods.     

Pyruvate decarboxylase encoded by the PDC1 gene contributes, at least partially, to the decarboxylation of alpha-ketoisocaproate for isoamyl alcohol formation in Saccharomyces cerevisiae

Isoamyl alcohol is an important flavor component of yeast-fermented alcoholic beverages. To identify the enzyme and gene involved in the decarboxylation of alpha-ketoisocaproate (alpha-KIC) for isoamyl alcohol formation, the enzyme was partially purified and analyzed by mass spectrometry. The pyruvate decarboxylase encoded by the PDC1 gene was considered a likely candidate enzyme. Genetic analysis showed that the activity of alpha-KIC decarboxylase and production of isoamyl alcohol partially decreased in a pdc1 null mutant and increased in a transformant with a multi-copy plasmid carrying the PDC1 gene. These results indicate that pyruvate decarboxylase encoded by the PDC1 gene contributes, at least partially, to the decarboxylation of alpha-KIC for isoamyl alcohol formation.     

Clean-up method of forchlorfenuron in agricultural products for HPLC analysis

A simplified method for the determination of forchlorfenuron in agricultural products by HPLC with UV detection was investigated. A chopped sample homogenate from agricultural products was extracted with acetone. The extract was filtrated and concentrated. The residues was loaded onto a Chem Elut column and extracted with ethyl acetate. The crude extract was purified on Oasis HLB and Bond Elut PSA mini-columns using a mixture of methanol and ethyl acetate. Forchlorfenuron was analyzed by HPLC with UV detection (263 nm). HPLC separation was performed on an ODS column with methanol-water as the mobile phase. Recoveries of forchlorfenuron from several agricultural products fortified at the level of 0.1 microg/g were in the range of 87.6-99.5%. The limit of detection (S/N=3) was 0.005 microg/g in the sample.     

Microwave frequency effect in the formation of Au nanocolloids in polar and non-polar solvents

Given earlier observations that microwave frequencies can have a substantial effect on the photoactivity of a well-known photocatalyst (TiO(2)), in the synthesis of 3,6-diphenyl-4-n-butylpyridazine through a Diels-Alder process, and in the one-pot solvent-free synthesis of a room-temperature ionic liquid, we proceeded to examine the frequency effects of the 5.8 and 2.45 GHz microwave (MW) radiation in the synthesis of gold nanoparticles in non-polar media, such as oleylamine, which have a low dielectric constant (ε'), and we further examine differences in shape and size under otherwise identical temperature conditions when the synthesis of the gold nanoparticles was carried out in an ethylene glycol polar medium in the presence of polyvinylpyrrolidone. Whereas a change in microwave frequency from 2.45 to 5.8 GHz at equal microwave power levels led to the synthesis of gold nanoparticles in the non-polar media, a change in the microwave frequency had no effect on the size and shape of the gold nanoparticles synthesized in polar media for identical microwave power levels.     

Novel Mg-Zr-A-H (A = Li, Na) hydrides synthesized by a high pressure technique and their hydrogen storage properties

It is important to develop the hydrogen storage technology by creating novel metal hydrides. In the present study, the powder mixtures of 6MgH₂ + ZrH₂ + nAH (A = Li, Na; n = 0, 0.3, 0.7, 1.0) were reacted to synthesize quaternary hydrides by use of a high pressure technique. The crystal structures of the new hydrides were refined by the Rietveld method based on the synchrotron XRD data. By reacting 6MgH₂ + ZrH₂ + nLiH, the quaternary hydrides with simple FCC-type structure were formed. In the case of 6MgH₂ + ZrH₂ + nNaH, novel quaternary hydrides with Ca₇Ge type structure were formed as well as the hydrides with simple FCC structure. The hydrogen storage capacities were around 6 wt.% according to the pressure-composition isotherm measurements. The formation enthalpies of the quaternary hydrides with simple FCC structure were proved to be lower while the enthalpies of the Mg-Zr-Na-H hydrides with Ca₇Ge type structure were higher, than that of the ternary Mg-Zr-H hydride obtained by reacting the basic system 6MgH₂ + ZrH₂. The hydrogen releasing temperatures of the quaternary Mg-Zr-A-H hydrides were slightly lower than that of the ternary Mg-Zr-H hydride.     

Probabilistic Dynamic Framed Slotted ALOHA for RFID Tag Identification

In this paper, we study radio frequency identification tag identification problems using framed slotted ALOHA protocol. Each tag will be assumed to participate in the contention with a certain probability. Then, the frame size and the probability will be dynamically controlled by the reader in every reading round so that all the tags can be detected in a short period of time. Moreover, we propose a practical way of controlling the probability in terms of transmit power control, assuming Additive White Gaussian Noise channel or flat Rayleigh fading channel. Computer simulation results demonstrate the effectiveness of the proposed method.     

WDM passive network design for small wavelength-count in local area/home applications

Passive optical networks are attractive due to their enhanced reliability, reduced electrical power consumption, and small latency. This paper determines the feasibility of WDM (Wavelength Division Multiplexing) passive networks with low wavelength count for small environments such as buildings/homes from the viewpoint of the physical network configuration. After describing the general characteristics of WDM passive networks in the bus, star, and ring configurations, we elucidate the optical path losses to find design solutions when the three physical configurations are used to create small networks. It is concluded that the star configuration is the most feasible approach. The bus and ring are also feasible only for small areas and low wavelength counts.