Environmentally friendly coloured materials: cellulose/titanium dioxide/inorganic pigment composite spherical microbeads prepared by viscose phase-separation method

In order to develop environmentally friendly coloured materials, cellulose composite spherical microbeads hybridised with titanium dioxide (TiO₂) particles and inorganic pigment were prepared by a phase-separation method using viscose and an aqueous solution containing sodium polyacrylate. Findings regarding the relationships between cellulose xanthate and the electronic characteristics of TiO₂ particles used in the cellulose/inorganic material composite sphering process are also reported. These findings suggest that the location of TiO₂ particles in cellulose microbeads is related to electrical repulsion between the xanthate (CSS⁻) group and TiO₂. The use of TiO₂ powder as colour pigment is limited, as its colour is white. The cellulose composite spherical microbeads covered with TiO₂ and Fe₂O₃ particles were developed by addition of iron oxide (Fe₂O₃). Their surfaces were viewed by laser microscope and using SEM images. These composite microbeads retained the photocatalytic property of TiO₂. Cellulose/TiO₂/Fe₂O₃ composite spherical microbeads with both colour function and photocatalytic properties were successfully prepared.     

Engineering of alpha1-antitrypsin variants selective for subtilisin-like proprotein convertases PACE4 and PC6: importance of the P2' residue in stable complex formation of the serpin with proprotein convertase

Furin and PACE4, members of the subtilisin-like proprotein convertase (SPC) family, have been implicated in the metastatic progression of certain tumors in addition to the activation of viral coat proteins and bacterial toxins, indicating that these enzymes are potential targets for therapeutic agents. Alpha1-Antitrypsin Portland is an engineered alpha1-antitrypsin designed as a furin-specific inhibitor and has been used as a tool in the functional analysis of furin. In this work, we engineered rat alpha1-antitrypsin to create a PACE4-specific inhibitor. Substituting Arg-Arg-Arg-Arg for Ala-Val-Pro-Met(352) at P4-P1 and Ala for Leu(354) at P2' created a potent PACE4- and PC6-specific inhibitor. This variant (RRRRSA) formed an SDS- and heat-stable serpin/proteinase complex with PACE4 or PC6 and inhibited both enzyme activities. The RRRRSA variant was efficiently cleaved by furin without formation of the stable complex. This is the first report of a highly selective protein-based inhibitor of PACE4 and PC6. This inhibitor will be useful in delineating the roles of PACE4 and PC6 localized in the extracellular matrix.     

Evaporation characteristics of multi-component fuel

The maximum liquid phase penetration and evaporation behavior was investigated by using simultaneous measurement for mie-scattered light images and shadowgraph ones. The objective of this study was to analyze effect of variant parameters and fuel properties on evaporation behavior, and to investigate liquid phase penetration for the single- and multi-component fuels. The experiments were conducted in a constant-volume vessel with optical access. Fuel was injected into the vessel with electronically controlled common rail injector. It was observed that: liquid phase length is influenced by fuel properties. High-boiling point fuel within the multi-component fuel controls liquid phase length.     

Activated carbon adsorption of trichloroethylene (TCE) vapor stripped from TCE-contaminated water

Ground water contaminated with trichloroethylene (TCE) used in electronic, electric, dry cleaning and the like industries is often treated by air-stripping. In this treatment process, TCE in its vapor form is stripped from ground water by air stream and sometimes emitted into the atmosphere without any additional treatments. Activated carbon adsorption is one of the practical and useful processes for recovering the TCE vapor from the exhaust air stream. However, adsorption of the TCE vapor from the stripping air stream onto activated carbons is not so simple as that from dry air, since in the exhaust air stream the TCE vapor coexists with water vapor with relatively high concentrations. The understanding of the adsorption characteristics of the TCE vapor to be adsorbed on activated carbon in the water vapor-coexisting system is essential for successfully designing and operating the TCE recovery process. In this work, the adsorption equilibrium relations of the TCE vapor adsorption on activated carbons were elucidated as a function of various relative humidity. Activated carbon fibers (ACFs) were used as model activated carbon. The adsorption equilibrium relations were studied by the column adsorption method. The adsorption isotherms of TCE vapor adsorbed on sample ACFs were successfully correlated by the Dubinin-Radushkevich equation for both cases with and without coexistent water vapor. No effects of coexistent water vapor were found on the limiting adsorption volume. However, the adsorption characteristic energy was significantly reduced by the coexistence of water vapor and its reduction was successfully correlated with the equilibrium amount of water vapor adsorbed under the dynamic condition.     

Physician-received scatter radiation with angiography systems used for interventional radiology: comparison among many X-ray systems

Radiation protection for interventional radiology (IR) physicians is very important. Current IR X-ray systems tend to use flat-panel detectors (FPDs) rather than image intensifiers (IIs). The purpose of this study is to test the hypothesis that there is no difference in physician-received scatter radiation (PRSR) between FPD systems and II systems. This study examined 20 X-ray systems in 15 cardiac catheterisation laboratories (11 used a FPD and 9 used an II). The PRSR with digital cineangiography and fluoroscopy were compared among the 20 X-ray systems using a phantom and a solid-state-detector electronic pocket dosemeter. The maximum PRSR exceeded the minimum PRSR by ~12-fold for cineangiography and ~9-fold for fluoroscopy. For both fluoroscopy and digital cineangiography, the PRSR had a statistically significant positive correlation with the entrance surface dose (fluoroscopy, r = 0.87; cineangiography, r = 0.86). There was no statistically significant difference between the average PRSR of FPDs and IIs during either digital cineangiography or fluoroscopy. There is a wide range of PRSR among the radiography systems evaluated. The PRSR correlated well with the entrance surface dose of the phantom in 20 X-ray units used for IR. Hence, decreasing the dose to the patient will also decrease the dose to staff.     

Distributions of density and fission products in the reaction product between irradiated MOX fuel and molten zircaloy-2

Two- and three-dimensional images were obtained by X-ray CT in the reaction product between zircaloy-2 cladding tube and MOX fuel. The gamma-ray intensity distributions in the same specimen were also obtained by gamma-ray measurements of two fission products (Cs-137 and Eu-154) and one neutron-activated nuclide (Co-60). The average values of the fuel density (about 10.5 g/cm³) and the cladding density (about 6.55 g/cm³) were obtained in the metallic phase region by evaluation of the density distributions on two-dimensional X-ray CT images. The distributions of the crushed fuel pellet and the pores were also clearly observed in the three-dimensional X-ray CT images. The following results were found from the gamma-ray measurement. First, Cs-137 was observed in the unreacted fuel region and the pore region in the metallic phase region. Second, Eu-154 was widely distributed to all regions. Finally, Co-60 was confirmed only in the metallic phase region.     

Atomic-scale cellular model and profile simulation of Si etching: Formation of surface roughness and residue

Formation mechanisms for profile anomalies such as surface roughness and residue have been investigated numerically and experimentally for Si etching in Cl₂/O₂ plasmas. The numerical simulation employed an atomic-scale cellular model (ASCeM) based on the Monte Carlo algorithm, which reproduced the feature profile evolution experimentally observed during etching at increased O₂ concentrations. A comparison between simulation and experiment indicated that the local surface oxidation induces surface roughness at the bottom of the feature during etching; then, synergistic effects between surface oxidation and ion scattering in microstructural features on roughened surfaces increase the surface roughness, which in turn causes a number of significant residues or micropillars on bottom surfaces of the feature. In practice, in roughened microstructural features, geometrical shadowing effects for neutral oxygen suppress the surface oxidation at the local feature bottom, where the energetic ion incidence is increased owing to ion scattering on sidewalls of the local feature.