Resistance of thermal-sprayed duplex coating composed of aluminum and 80Ni-20Cr alloy against aqueous corrosion

The development of corrosion-resistant sprayed coatings without sealing is required to increase the reliability of the thermal spray coating method and to expand the field of application for wet corrosion environments. The conventional wire flame-sprayed aluminum coating on steel without sealing has poor resistance against aqueous corrosion and has restricted practical use. A duplex coating composed of sprayed aluminum on an 80Ni-20Cr alloy undercoat exhibited sufficient resistance in a hot, near-neutral aqueous environment through a trial use in a vegetable oil process. In this paper, the mechanism of corrosion resistance of the duplex coating is investigated by electrochemical polarization measurements and electron probe microchemical analysis (EPMA) to examine the individual role of each layer and the change of the microstructure with time.     

A framework for pedestrian comfort navigation using multi-modal environmental sensors

Environments significantly influence the sensation of pedestrians, while sensing and navigation technologies can help people improve their trip comfort. In this paper, we present an integrated framework, named NaviComf, which constructs pedestrian navigation systems to improve comfort in time varying environments taking into account the heterogeneous environmental factors. With NaviComf we aim to systematically provide solutions to the four key issues: (1) how to organize the huge amount of sensor data, (2) how to forecast future environmental information, (3) how to incorporate the heterogeneous environmental factors, and (4) how to select optimal paths in time varying environments. We have gathered sensor data of air temperature, relative humidity, and pedestrian congestion in real environments. We have also implemented a prototype system on the basis of the framework using the sensor data. Results of simulations and evaluations show that NaviComf can efficiently provide more comfortable paths as compared with the traditional navigation method.     

Induction of differentiation of myelogenous leukemia cells by humulone, a bitter in the hop

The active form of vitamin D, 1alpha,25-dihydroxyvitamin D3 (VD3), inhibits proliferation and induces differentiation of myelomonocytic leukemia cells, but its clinical use is limited by the adverse effect of hypercalcemia. VD3 mobilizes calcium stores from bone by inducing the dissolution of bone mineral and matrix. We have recently found that humulone, a bitter in the hop extract for beer brewing, effectively inhibits bone resorption. In this study we examined the effect of humulone on the differentiation of human myelogenous leukemia cells. Humulone alone inhibited the growth of monoblastic leukemia U937 cells while only slightly increasing differentiation markers such as nitroblue tetrazolium (NBT)-reducing and lysozyme activities. Humulone effectively enhanced the differentiation-inducing action of VD3. Other myelomonocytic leukemia cells were induced to differentiate by VD3 and this was also enhanced by humulone. Since humulone is a less-toxic inhibitor of bone resorption, the combination of humulone and VD3 may be useful in differentiation therapy of myelomonocytic leukemia.     

Photo-catalytic film deposition by atmospheric TPCVD

TiO₂ film were deposited by atmospheric thermal plasma chemical vapor deposition (TPCVD) method to investigate the rapid process for functional film deposition. The experiment was conducted under the condition where working gas was Ar, working gas flow rate was 20 l/min, deposition distance was varied from 30 to 200 mm and spraying time was 10 min. Ethanol diluted titanium tetra buthoxide was used as starting material. Consequently, even in this process TiO₂ films including anatase could be deposited, and the results of wettability and methylene blue decoloration testings suggest that the TiO₂ films have good photo-catalytic property. Besides, by using extension nozzle, columnar structure film could be deposited due to a perfect starting material vaporization. From these results, the proposed process seemed to be highly promising for the rapid formation of functional thin films.     

The dynamic balance of import and export of zinc in Escherichia coli suggests a heterogeneous population response to stress

Zinc is essential for life, but toxic in excess. Thus all cells must control their internal zinc concentration. We used a systems approach, alternating rounds of experiments and models, to further elucidate the zinc control systems in Escherichia coli. We measured the response to zinc of the main specific zinc import and export systems in the wild-type, and a series of deletion mutant strains. We interpreted these data with a detailed mathematical model and Bayesian model fitting routines. There are three key findings: first, that alternate, non-inducible importers and exporters are important. Second, that an internal zinc reservoir is essential for maintaining the internal zinc concentration. Third, our data fitting led us to propose that the cells mount a heterogeneous response to zinc: some respond effectively, while others die or stop growing. In a further round of experiments, we demonstrated lower viable cell counts in the mutant strain tested exposed to excess zinc, consistent with this hypothesis. A stochastic model simulation demonstrated considerable fluctuations in the cellular levels of the ZntA exporter protein, reinforcing this proposal. We hypothesize that maintaining population heterogeneity could be a bet-hedging response allowing a population of cells to survive in varied and fluctuating environments.     

Bonding adhesive strength for plasma spray with cathode spots of low-pressure arc after grit blasting and removal of oxide layer on metal surface

Cathode spots of a low-pressure arc can remove oxide layers and evaporate impurities on metal surfaces. Removal of the oxide layer using cathode spots is expected to solve recent obstacles due to chemical and mechanical cleaning methods. Various phenomena of cathode spots have been investigated for pre-treatment of atmospheric pressure plasma spray (APPS). This study treated the surface shapes of oxide and non-oxide samples using a composite pre-treating method: cathode spots after grit blasting. In addition, the samples are compared with conventionally treated cathode spots and mechanical blasted surfaces. Results show that roughness on the sample surfaces becomes higher in concomitance with the initial oxide layer thickness. This fact reveals the factors those dominant bonding strength on the pre-treated surface using cathode spots of a low-pressure arc. Bonding strength becomes higher in relation to the arithmetical mean height of the surface roughness caused by the initial oxide layer thickness. Bonding strength is higher when the mean spacing of profile irregularities is narrower. The bonding adhesive strength after treatment using cathode spots after grit blasting is greater than 90 MPa. However, cathode spot treatment must be limited not to destroy the projection formed by melting after grit blasting in an arc time up to 5 s. And basically the removal characteristics of oxide layer using the cathode spots were discussed on the trace, roughness, number of cathode spots in time and pressure, moving speed on the metal surface, etc.     

Characterization and functional properties of soybean high-molecular-mass polysaccharide complex

Soybean soluble polysaccharide (SSPS), extracted from the by-product obtained during isolation of soybean protein, is an anionic polysaccharide that stabilizes milk proteins under acidic conditions. We developed a high-molecular-mass complex of SSPS cross-linked via phosphate (SSPS-HC; absolute molecular weight = 2850 kg/mol, radius of gyration = 106 nm), and found that it has different protein stabilization properties when compared with the original SSPS (absolute molecular weight = 550 kg/mol, radius of gyration = 36 nm). The objective of this work was not only to study the rheological properties of SSPS-HC, but also clarify its protein-stabilizing properties in comparison with SSPS; if molecular mass or negative charge affected protein dispersion. Irrespective of high-molecular-mass, SSPS-HC possessed similar rheological properties to SSPS such as low viscosity in aqueous solution. The absolute negative charges of SSPS-HC measured by a zeta potential analyzer at pH range of 2.0–7.0 were higher than those of SSPS. Acidified milk drinks prepared with 8.4% non-fat milk solids and 0.4% SSPS-HC or SSPS showed low viscosity and small protein particle size, and did not aggregate for 14 days. The thickness of the hydrated layer, which was formed on the surface of protein particles by SSPS molecules measured after hemicellulase treatment with DLS (dynamic light scattering), was estimated to be about 89 nm for SSPS-HC and 33 nm for SSPS. These numerical values were in good relation to the molecular diameter of SSPS-HC and SSPS in aqueous solution measured by DLS and AFM image, and suggested that protein particles were dispersed and the hydrated monolayer made on the surface of protein particles by SSPS-HC or SSPS molecules prevented aggregation. However, stabilizing pH ranges were different with stability of SSPS-HC at pH range of 4.0–4.8 and stability for SSPS at pH range of 3.6–4.2. In addition to the difference in the molecular mass and absolute negative charge, the phosphate groups of SSPS-HC were possibly influenced on the protein-dispersing property approximately at isoelectric point of milk protein; SSPS-HC prevent aggregation of casein by accelerating solubility of calcium phosphate under acidic conditions as is already reported in the starches phosphorylated.