Production of Lacto-N-biose I Using Crude Extracts of Bifidobacterial Cells

Lacto-N-biose I (LNB) is supposed to represent the bifidus factor in human milk oligosaccharides, and can be practically produced from sucrose and GlcNAc using four bifidobacterial enzymes, 1,3-β-galactosyl-N-acetylhexosamine phosphorylase, sucrose phosphorylase, UDP-glucose-hexose 1-phosphate uridylyltransferase, and UDP-glucose 4-epimerase, recombinantly produced by Escherichia coli. Here the production of LNB by the same enzymatic method without using genetically modified enzymes to consider the use of LNB for a food ingredient was reported. All four enzymes were produced as the intracellular enzymes of Bifidobacterium strains. The mixture of the crude extracts contained all four enzymes, with other enzymes interfering with the LNB production, namely, phosphoglucomutase, fructose 6-phosphate phosphoketolase, and glycogen phosphorylase. The first two interfering enzymes were selectively inactivated by heat treatment at 47 °C for 1 h in the presence of pancreatin, and glycogen phosphorylase was disabled by hydrolyzing its possible acceptor molecules using glucoamylase. Finally, 91 % of GlcNAc was converted into LNB in the 100-mL reaction mixture containing 300 mM GlcNAc.     

Computational cavitation flows at inception and light stages on an axial-flow pump blade and in a cage-guided control valve

Cavitation flows induced around an axial-flow pump blade and inside a high pressure cage-type valve are simu-lated by a two-dimensional unsteady Navier-Stokes analysis with the simplest treatment of bubble dynamics.Thefluid is assumed as a continuum of homogeneous dispersed mixture of water and vapor nuclei.The analysis isaimed to capture transient stages with high amplitude pressure change during the birth and collapse of the bubbleespecially at the stage of cavitation inception.By the pump blade analysis,in which the field pressure is moderate,cavitation number of the inception and locations of developed cavitation are found to agree with experimental re-suits in a wide flow range between high incidence and negative incidence.In the valve flow analysis,in which thewater pressure of 5MPa is reduced to 2MPa,pressure change responding to the bubble collapse between the vaporpressure lower than 1 KPa and the extreme pressure of higher than 10~4 KPa is captured through a stable computa-tion.Location of the inception bubble and pressure force to the valve plug is found agree well with the respectiveexperimental features.     

WO3/BiVO4 composite photoelectrode prepared by improved auto-combustion method for highly efficient water splitting

We report on the improvement in the water splitting efficiency of a WO₃/BiVO₄ composite photoelectrode by the application of an improved auto-combustion method to the preparation of porous BiVO₄ thin films. The unique feature of this preparation method is the addition of both NH₄NO₃, as a strong oxidizing agent, and an organic additive into BiVO₄ precursor solution. The local decomposition heat of the organic additive and oxidizing agent created a porous film with small, highly crystalline BiVO₄ particles. The photoelectrode has many advantages over existing ones, such as the high light-harvesting efficiency (LHE), a single BiVO₄ phase, the facile access of the holes to the photoelectrode/electrolyte interface, and the ease of water and oxygen diffusion. The maximum incident photon-to-current efficiency (IPCE) was estimated to be 64% (at 440 nm, 1.23 V vs. RHE) and the applied bias photon-tocurrent efficiency (ABPE) reached as high as 1.28%. This ABPE value is highest among all oxide semiconductor photoelectrodes reported previously, except for the case of a stacking photoelectrode system.     

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     

In situ TEM study on changes in structure and electrical conductance of carbon nanotube-gold contact induced by local joule heating

Electrical conductance of multi-walled carbon nanotubes (MWCNTs) with closed and open tips contacting with a gold (Au) electrode was studied by in situ transmission electron microscopy. When a current density through the contact region reached a threshold value of 2.6 × 10⁸ A/cm², the MWCNT tip was embedded into the Au surface by local melting of Au, and the total resistance was reduced with the increase of the contact area. Conductance per unit area at the contact between the MWCNT and Au electrode for the open-ended MWCNT is four times larger than that for the close-ended one, which is due to the direct connection of inner walls of the open-ended MWCNT with the Au surface.     

Phosphorus flame retardants in indoor dust and their relation to asthma and allergies of inhabitants

Organophosphate esters are used as additives in flame retardants and plasticizers, and they are ubiquitous in the indoor environment. Phosphorus flame retardants (PFRs) are present in residential dust, but few epidemiological studies have assessed their impact on human health. We measured the levels of 11 PFRs in indoor floor dust and multi‐surface dust in 182 single‐family dwellings in Japan. We evaluated their correlations with asthma and allergies of the inhabitants. Tris(2‐butoxyethyl) phosphate was detected in all samples (median value: 580 μg/g in floor dust, 111 μg/g in multi‐surface dust). Tris(2‐chloro‐iso‐propyl) phosphate (TCIPP) was detected at 8.69 μg/g in floor dust and 25.8 μg/g in multi‐surface dust. After adjustment for potential confounders, significant associations were found between the prevalence of atopic dermatitis and the presence of TCIPP and tris(1,3‐dichloro‐2‐propyl) phosphate in floor dust [per log₁₀‐unit, odds ratio (OR): 2.43 and 1.84, respectively]. Tributyl phosphate was significantly associated with the prevalence of asthma (OR: 2.85 in floor dust, 5.34 in multi‐surface dust) and allergic rhinitis (OR: 2.55 in multi‐surface dust). PFR levels in Japan were high compared with values reported previously for Europe, Asia‐Pacific, and the USA. Higher levels of PFRs in house dust were related to the inhabitants' health status.     

Analysis of spatial smoothing effect of short‐term fluctuation of global solar radiation based on data including quantization error

Photovoltaic (PV) systems are attracting attention as one of the promising countermeasures against global warming and the environmental issues. However, the generation output from PV systems is generally unstable and unpredictable. Therefore, large penetration of PV systems may cause some serious impacts on power system operation, such as load frequency control, voltage regulation, etc. Estimation of the influences of PV system installation is becoming important, but it requires simultaneous multipoint solar radiation measurements. The Japan Meteorological Business Support Center has provided 1‐minute meteorological data observed in Japan, but its solar radiation data includes quantization errors. This paper proposes a regeneration method for solar radiation data including quantization errors. It also analyzes the spatial smoothing effect of global solar radiation fluctuations. © 2012 Wiley Periodicals, Inc. Electr Eng Jpn, 180(3): 55–63, 2012; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21274     

Mangrove research and coastal ecosystem studies with SPOT-4 HRVIR and TERRA ASTER in the Arabian Gulf

Mangroves reach their optimal development in the wet tropics although some little known mangrove stands are reported in subtropical arid coastlines especially from the Red Sea to Pakistan where they form one of the driest mangrove habitats in the world. Because they constitute the only available evergreen forest in hyper-arid warm coastal areas, the main wetlands for migratory birds and essential nursery ground for many species of fish, it is imperative to produce a sufficiently accurate map for monitoring their changes and for their protection. The main objective of the present work is to test and to select the best methodological approach to discriminate and map the mangroves and related coastal ecosystems in the United Arab Emirates (UAE), between Abu Dhabi and Dubai, a coastal stretch about 750?km long. It was found that the best practical results were produced by the Maximum Likelihood and Mahalanobis classifications although some limitations remain unsolved, especially in open ecosystems, which are common in arid areas. Moreover, SPOT-4 High-Resolution Visible Infra-Red (HRVIR) data proves at least as efficient as TERRA ASTER data, in spite of a slightly finer ground resolution and the great number of channels for ASTER. Ultimately, the most appropriate working scale for mapping coastal habitats, compatible with pixel size, is in the order of 1/25 000.     

Photoactivable Elimination of Tumorigenic Human Induced Pluripotent Stem Cells by Using a Lectin–Doxorubicin Prodrug Conjugate

Human pluripotent stem cells (hPSCs) are attractive resources for regenerative medicine, but medical applications are hindered by their tumorigenic potential. Previously, a hPSC-specific lectin probe, rBC2LCN, was identified through comprehensive glycome analysis by using high-density lectin microarrays. Herein, a lectin–doxorubicin (DOX) prodrug conjugate, with controllable photolysis activation for the elimination of tumorigenic human induced pluripotent stem cells, has been developed. rBC2LCN was fused with a biotin-binding protein, tamavidin (BC2Tama), and the fusion protein was expressed in Escherichia coli and purified by means of affinity chromatography. BC2Tama was then conjugated with doxorubicin-photocleavable biotin (DOXPCB). The BC2Tama–DOXPCB conjugates were observed to bind to hPSCs followed by internalization. Upon exposure to ultraviolet light, DOX was released inside the cells, which allowed specific killing of the hPSCs. Thus, BC2Tama–DOXPCB should be useful for the targeted elimination of hPSCs contained in hPSC-derived cell therapy products. This is the first report of the generation of lectin–prodrug conjugates. BC2Tama should be applicable for the targeted delivery of various types of biotinylated compounds into hPSCs.