Locomotion Control of MEMS Microrobot Using Pulse‐Type Hardware Neural Networks

This paper presents the locomotion control of a microelectromechanical system (MEMS) microrobot. The MEMS microrobot demonstrates locomotion control by pulse‐type hardware neural networks (P‐HNN). P‐HNN generate oscillatory patterns of electrical activity like those of living organisms. The basic component of P‐HNN is a pulse‐type hardware neuron model (P‐HNM). The P‐HNM has the same basic features as biological neurons, such as the threshold, the refractory period, and spatiotemporal summation characteristics, and allows the generation of continuous action potentials. P‐HNN has been constructed with MOSFETs and can be integrated by CMOS technology. Like living organisms, P‐HNN has realized robot control without using software programs or A/D converters. The size of the microrobot fabricated by MEMS technology was 4 × 4 × 3.5 mm. The frame of the robot was made of a silicon wafer, equipped with rotary actuators, link mechanisms, and six legs. The MEMS microrobot emulated the locomotion method and the neural networks of an insect by rotary actuators, link mechanisms, and the P‐HNN. We show that the P‐HNN can control the forward and backward locomotion of the fabricated MEMS microrobot, and that it is possible to switch its direction by inputting an external trigger pulse. The locomotion speed was 19.5 mm/min and the step size was 1.3 mm. © 2013 Wiley Periodicals, Inc. Electr Eng Jpn, 186(3): 43–50, 2014; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.22473     

Experimental analysis of 2D-unsteady temperature field by using Mach-Zehnder interferogram images

A measurement method for an unsteady temperature field by using a Mach-Zehnder interferometer and image processing technique is presented. In this study, the results measured by this method were compared with the calculated results under Reynolds numbers (Re = UL/v) ranging to less than 350 in the steady-state. The unsteady characteristics of the local Nusselt numbers (Nu_x = α_xL/λ) around an elastically vibrating plate were investigated under the conditions that the reduced frequency (N = 1/Ro) ranged from 4.8 to 8.6 and the amplitude of vibration was kept small relative to the plate length. In this study it was clarified that the distributions of the Local Nusselt numbers were observed flutteringly, and that the phase of the time-averaged Nusselt number is delayed compared to the phase of the velocity at the trailing edge. These results indicate that the enhancement of the time-averaged heat transfer coefficient around the vibrating plate depended on the Rossby number. © 1997 Scripta Technica. Inc. Heat Trans Jpn Res. 25 (2): 88–102, 1996     

Effects of fatty acid and emulsifier on the complex formation and in vitro digestibility of gelatinized potato starch

The effects of fatty acid, monoacylglycerol, and polyglycerol fatty acid ester with varying chain length in their acyl chains on the extent of complex formation (complex index) and in vitro enzymatic digestibility of gelatinized potato starch were investigated. The complex index increased with increase in the concentration of the ligands (fatty acid, monoacylglycerol, and polyglycerol fatty acid ester), with the plateau in the complex index value depending on the type of ligands. In comparison of complex index among fatty acid-samples, the complex index maximum increased as the chain length increased up to octanoic acid and then decreased. In comparison of complex index among fatty acid-, monoacylglycerol-, and polyglycerol fatty acid ester-samples at each acyl chain, the complex index maximum followed the order polyglycerol fatty acid ester > monoacylglycerol > fatty acid. Fatty acid, monoacylglycerol, and polyglycerol fatty acid ester with long acyl chains greatly reduced the enzymatic hydrolysis of starch. Polyglycerol fatty acid ester with palmitic acid chains was the strongest inhibitor of starch hydrolysis, suggesting that further complex formation may occur during the hydrolysis of gelatinized starch (enzyme-annealing).     

Mumefural and related HMF derivatives from Japanese apricot fruit juice concentrate show multiple inhibitory effects on pandemic influenza A (H1N1) virus

Fruit-juice concentrate of Japanese apricot (Prunus mume Sieb. et Zucc.) has been shown to be effective against influenza A infection in MDCK cells. In this study, we isolated five components from the fruit-juice concentrate of Japanese apricot, 5-(hydroxymethyl)-2-formylfuran (HMF), 1-[5-(2-formylfuryl)methyl]dihydrogen 2-hydroxypropane-1,2,3-tricarboxylate (mumefural, MF), 2-[5-(2-formylfuryl)methyl]dihydrogen 2-hydroxypropane-1,2,3-tricarboxylate (MF‘), 1-[5-(2-formylfuryl)methyl]hydrogen 1-hydroxyethane-1,2-dicarboxylate (MA1) and 2-[5-(2-formylfuryl)methyl]hydrogen 1-hydroxyethane-1,2-dicarboxylate (MA2), and investigated their inhibitory activities against the novel influenza A/Narita/1/2009 (H1N1) pandemic virus hemagglutinin and neuraminidase functions, which are essential for viral attachment and budding, respectively. An hemagglutination inhibition assay indicated that MF and MF‘ were effective at minimum hemagglutination concentrations of 3.1 and 6.3 mM, respectively. An inhibition study for sialidase activity of the neuraminidase spike showed that MF was the most active anti-sialidase compound with an IC₅₀ value of 0.21 ± 0.01 mM, followed by MA2 (IC₅₀, 0.71 ± 0.09 mM), MA1 (IC₅₀, 1.64 ± 0.31 mM) and MF‘(IC₅₀, 1.62 ± 0.22 mM). Furthermore, MF was shown to inhibit the growth of the pandemic virus in a dose-dependent manner (62 ± 3% inhibition at 5 mM). The results suggest that MF, a citric acid ester linked to HMF at the 1-position of the propane backbone, might be a lead compound for the development of anti-influenza A inhibitors.     

Light-Wavelength-Based Quantitative Control of Dihydrofolate Reductase Activity by Using a Photochromic Isostere of an Inhibitor

Photopharmacology has attracted research attention as a new tool for achieving optical control of biomolecules, following the methods of caged compounds and optogenetics. We have developed an efficient photopharmacological inhibitor—azoMTX—for Escherichia coli dihydrofolate reductase (eDHFR) by replacing some atoms of the original ligand, methotrexate, to achieve photoisomerization properties. This fine molecular design enabled quick structural conversion between the active “bent” Z isomer of azoMTX and the inactive “extended” E isomer, and this property afforded quantitative control over the enzyme activity, depending on the wavelength of irradiating light applied. Real-time photoreversible control over enzyme activity was also achieved.     

Influence of the Mass Transfer of Water in Cartilaginous Tissue on the Temperature Field Induced by Laser Radiation

A study is made of the influence of the mass transfer of water on the temperature field occurring in cartilaginous tissue under the action of laser pulses. Two different mechanism of mass transfer of water in cartilaginous tissue (moleculardiffusion mechanism and laminar flow) have been considered in solving heat and masstransfer equations. The calculations have shown that the maximum temperature is attained inside the sample because of the evaporation of water from the biologicaltissue surface. The influence of different parameters of laser radiation and mass transfer of water on the surface temperature, on the maximum value of the temperature, on the position of the temperature maximum, and on the characteristic time at which the diffusionlimited relaxation of stresses in the cartilaginous tissue occurs has been analyzed.     

Generation of high-frequency oscillations in local circuits of rat somatosensory cortex cultures

1. Rhythmic cortical activity was investigated with intracellular recordings in cortex-striatum-mesencephalon organotypic cultures grown for 42 +/- 3 (SE) days in vitro. 2. Electrical stimulation of supragranular layers induced a self-sustained high-frequency oscillation (HFO) in pyramidal neurons and interneurons. 3. The HFO started 197 +/- 39 ms after stimulation and had a mean duration of 1.0 +/- 0.2 s and an initial frequency of 38 +/- 2 Hz. A decrease in frequency at a rate of 11.5 +/- 2.7 Hz/s started on average 547 +/- 109 ms after the onset of the HFO. 4. During the HFO, local interneurons and pyramidal neurons synchronized their activities. The synaptic origin of the HFO was confirmed by its reversal potential at -57 +/- 4 mV. 5. These results suggest that a self-maintained HFO can be induced in local cortical circuits by excitation of supragranular layers. This HFO would facilitate synchronization between distant cortical and thalamic regions.     

A Strategy for Discovering Heterochiral Bioactive Peptides by Using the OB2nP Library and SPOTs Method

d -Amino acid containing peptides are promising as drug lead compounds because of their expected higher stability in vivo. A heterochiral random peptide library called the one-bead–2ⁿ-peptide (OB2ⁿP) library, which can display 2ⁿ peptide diastereomers per bead, has been developed. Through screening of the OB2ⁿP library and subsequent binding assay among the peptide diastereomers synthesized in parallel by means of the SPOTs method, new heterochiral mimotopes for the anti-β-endorphin monoclonal antibody have been obtained. One mimotope was a new ligand for the μ-opioid receptor. The screening strategy enabled d -amino acid containing drug leads to be obtained efficiently by expanding searchable chemical space without increasing the experimental scale.     

Suppression of heat-induced HSF activation by CDDP in human glioblastoma cells

To confirm whether or not the alar cartilage of the unilateral cleft lip nose is primarily hypoplastic as compared with the noncleft side, 35 unilateral cleft lip nasal patients who had no previous nasal surgery underwent direct measurement of the lateral crus of alar cartilage on both sides during their nasal tip plasties. Both lower lateral cartilages were dissected freely, and the thickness was measured at the intercrural, middle, and distal portions. The width was measured at the widest portion, and the length was measured from the intercrural point to the distal end. Two-mm-punch biopsies were obtained from each cartilage for histologic study. The lateral crus of the cleft side was no smaller than that of the noncleft side. Histologically, no difference was ascertained. In conclusion, we think the lateral crus of the alar cartilage of the cleft side is not hypoplastic. Therefore, external factors such as soft-tissue defect or external abnormal vector force are more attributable than intrinsic factors to the development of cleft lip nasal deformity.     

Morphological organization of the globus pallidus-subthalamic nucleus system studied in organotypic cultures

The morphological organization of the globus pallidus (GP), the subthalamic nucleus (STN), and the pallidosubthalamic projection was studied in organotypic cultures. Coronal slices from the GP, the STN, the striatum (CPu), and the cortex (Cx) were taken from the rat after postnatal days 0-2 and grown for 2 or 5-6 weeks. For analysis, immunocytochemistry against glutamate (GLU), parvalbumin (PV), and calretinin (CR) was combined with confocal microscopy. After 2 weeks in vitro, the STN showed a densely packed, homogeneous GLU-immunoreactive (ir) cell population. Pallidal GLU-ir neurons were heterogeneous, consisting of large-sized weakly GLU-ir neurons and small-sized intensively GLU-ir neurons. After 5-6 weeks in vitro, pallidal axons had radiated from numerous large-sized PV-ir cells and selectively innervated the STN, where they heavily ramified. Cultured STN neurons were not stained for PV; however, multipolar intensely PV-ir neurons were located at the border of the STN with their dendrites oriented towards the STN. Double labeling for PV and CR in both mature cultures and in the adult rat revealed that the culture CR-ir neurons from the GP, the Cpu, and from areas adjacent to the STN were different from cultured PV-ir neurons and their morphologies and distribution corresponded to that in vivo. These results demonstrate that 1) cultured CP and STN neurons display similar morphologies found in in vivo, 2) PV-ir pallidal neurons heavily and selectively innervate the STN; 3) there is a specific class of STN border neurons; and 4) in contrast to the in vivo situation, most cultured STN neurons are PV-negative.