Optimum design of agitator geometry for a dry stirred media mill by the discrete element method

Three different agitator geometries for a dry stirred media mill with a horizontal drum were studied experimentally and by DEM (discrete element method) simulation. Two optimized models, model A with stirring arms oriented in the same direction and model B with inclined stirring arms, achieved more rapid grinding with the lower adhesion of particles to the mill than the conventional stirring arms. Model A achieved the finest grinding with sharpest particle distribution.DEM simulation results suggested that rapid mixing, large collision energy, and a large number of collisions result in rapid grinding. DEM simulations of model A confirmed that the particle collision energy in this model was the highest of the models tested and resulted in the largest energy consumption and the largest temperature increase. In model B, DEM simulation results suggested that collision energy increased locally at the wall and resulted in a local temperature increase at the shaft. The high number of collisions in model B also resulted in rapid grinding but with a broad particle distribution. The decrease of the particle adhesion in models A and B was caused by a decrease in the collision energy between particles and the wall in the normal direction.     

High-field dissipation current waveform in e-beam-irradiated XLPEfilm at high temperature

We developed a detection method of ac dissipation current waveforms combined with a fast rising ac ramp voltage application as a new technique to evaluate the high-field dielectric properties and the dissipation current waveform over a very short time range. This measurement was carried out on electron beam irradiated crosslinked polyethylene film. At high temperature the high field tan δ and ac dissipation current show nonlinear electric field dependence and the dissipation current during decreasing field becomes larger than that during increasing field, suggesting the contribution of carrier injection from electrodes. The dissipation current waveforms in the high temperature region show the peak in the first part of each half cycle of a full waveform, and fast decrease in the latter part. This result is probably due to the hetero and home space charge formation caused by the injected carriers from the electrode     

mAb 5-1-6 nephropathy and nephrin

It is well established that the glomerular capillary wall consists of three layers: endothelial cell, glomerular basement membrane, and the slit diaphragm bridging foot processes of glomerular epithelial cell. Which structure in the glomerular capillary wall represents the primary filter for retaining plasma proteins is not clearly elucidated. An anti-slit diaphragm monoclonal antibody (mAb) 5-1-6 causes massive proteinuria in rats by single intravenous injection, which clearly indicates that the slit diaphragm plays a critical role for maintaining the barrier function of the glomerular capillary wall. Recently, we concluded that mAb 5-1-6 recognized a rat homolog of nephrin, a gene product of NPHS1. The expression of nephrin decreased in puromycin aminonucleoside nephropathy and adriamycin nephropathy as well as mAb 5-1-6-induced nephropathy, which suggested that nephrin was involved in the development of proteinuria in these proteinuric states. In mAb 5-1-6 nephropathy, the slit diaphragm was maintained morphologically normal, although nephrin expression dramatically decreased. The finding suggested that nephrin was not a sole component of the slit diaphragm. To better understand the structure of the slit diaphragm, it is particularly important to identify other components that build up the structure of the slit diaphragm together with nephrin.     

Exploring the “friction modifier” phenomenon: nanorheology of n‐alkane chains with polar terminus dissolved in n‐alkane solvent

Dilute solutions of two polar end‐functionalized linear alkanes (1‐hexadecylamine and palmitic acid), each dissolved in tetradecane, were confined between two mica surfaces and investigated using a surface forces apparatus modified to study shear nanorheology. These two solutions showed similar nanorheological properties that differed from those observed for pure n‐alkanes. In static measurements, a “hard wall”, rather than an oscillatory force, was observed as a function of film thickness. The polar alkane component formed a weakly adsorbed single layer at each mica surface, disrupting the layered structures found in neat n‐tetradecane. In dynamic experiments at low shear amplitude, the storage modulus G' exceeded the loss modulus G" at low frequencies; above some characteristic frequencies G' increased such that g' ≈ G", indicating significantly more energy loss through viscous modes at higher frequency. When the amplitude was varied at fixed frequency, no stick–slip was observed and the limiting value of the shear stress at high effective shear rate was an order of magnitude less than for unfunctionalized n‐alkanes at similar loads. Together, these results show that the addition of a small amount of polar alkane component, by disrupting the layered structures that would have been formed in the neat n‐alkane, is effective in suppressing static friction and reducing kinetic friction in the boundary lubrication regime. This revised version was published online in July 2006 with corrections to the Cover Date.     

An exploratory study for analyzing interactional processes of group discussion: the case of a focus group interview

The purposes of this study are (a) to establish a measurement for evaluating conversational impressions of group discussions, and (b) to make an exploratory investigation on their interactional processes which may affect to form those impressions. The impression rating and factor analysis undertaken first give us four factors concerning conversational impressions of “focus group interviews (FGIs)”: conversational activeness, conversational sequencing, the attitudes of participants and the relationships of participants. In relation to the factors of conversational activeness and conversational sequencing in particular, the microanalysis of four selected topical scenes from our database further shows that the behavior of the moderator and the interviewees is organized not independently but with reference to each other. The study thus emphasizes the importance of the integration of quantitative and qualitative approaches towards human interactions.

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Reflection and time-dependent computing: Experiences with the R2 architecture

In this paper we present an application of computational reflection in the programming oftime-dependent systems. A time-dependent system performs its tasks according to timing specifications specified within the system or imposed from outside the system. Reflective techniques can be applied to programming time-dependent systems because (1) some application programs require the introduction of a new language construct for specifying timing requirements and (2) different applications may require domain-specific scheduling algorithms. To allow a programmer to add or modify language constructs or scheduling algorithms, however, a clear reflective architecture and program interfaces must be provided. This paper proposes a concurrent object-based reflective architecture (R ² architecture) for time-dependent computing. This architecture is based on anindividual reflection scheme and introduces new meta-level objects (real-time meta objects) that are responsible for time-dependent capabilities. An alarm-clock object and a scheduler object are introduced, and message protocols between them and real-time meta objects are defined. We implemented this architecture on ABCL/R2 and created the Sampled Sound Player program as an application. With this application we provided three different scheduler objects and measured the impact of different scheduling algorithms on sound playback. The measured results show that a scheduler with more complex computations at the meta level exhibited less scheduling overhead, thus was capable of better sound playback. The other example, Time-dependent Graceful Degradation Scheme, demonstrates the programming of functionality degradation triggered by failure to satisfy timing specifications.     

Conformation study on the interactions of plasma proteins with anionic lipids and heparin

Summary Effects of anionic lipids and heparin on the conformation of plasma proteins, such as albumin, -globulin, and fibrinogen were investigated by evaluating both -helix and -structure contents from circular dichroism (CD) spectra. Sodium dodecyl sulfate and sodium dodecylbenzenesulfonate increased the -helix content of -globulin, and -structure content of fibrinogen accompanied with decreasing -helix content, while they stepwise disrupted the -helix of albumin with increasing their concentration. It was concluded that the hydrophobic interaction was predominant for binding albumin, while the electrostatic interaction affected the structural changes of -globulin more than hydrophobic interaction.     

Biological responses of novel high-toughness double network hydrogels in muscle and the subcutaneous tissues

The study evaluated biological reaction of four types of novel double network gels in muscle and subcutaneous tissues, using implantation tests according to the international guideline. The implantation tests demonstrated that, although poly (2-acrylamide-2-metyl-propane sulfonic acid)/poly (N,N′-dimetyl acrylamide) (PAMPS/PDMAAm) gel induced a mild inflammation at 1 week, the degree of the inflammation significantly decreased into the same degree as that of the negative control at 4 and 6 weeks. This gel has a potential to be applied as artificial cartilage. In addition, Cellulose/Gelatin gel showed the same degree of inflammation as that of the negative control at 1 week, and then, showed a gradually absorbable property at 4 and 6 weeks. This gel has a potential to be applied as an absorbable implant. The PAMPS/polyacrylamide and Cellulose/PDMAAm gels induced a significant inflammation at each week. These DN gels are difficult to be applied as clinical implants in the current situation.     

Decaarginine-PEG-artificial lipid/DNA complex for gene delivery: nanostructure and transfection efficiency

Oligoarginine conjugates are highly efficient vectors for the delivery of plasmid DNA into cells. Decaarginine-conjugated lipid (Arg10-PEG-lipid) was synthesized and the effects of Arg10-PEG-lipid concentration at a fixed DNA concentration on transfection efficiency and the structure of the complexes were studied below and above critical micelle concentration (CMC), and at the lipid nitrogen/DNA phosphate (N/P) ratio corresponding to transfection, respectively. Arg10-PEG-lipid at the concentration below CMC showed stronger interaction with DNA by fluorescence intensity distribution analysis, and significantly higher luciferase and green fluorescent protein expression than that above CMC. A phase-contrast cryo-transmission electron microscope (cryo-TEM) experiment showed that the morphology of the complexes depended on the N/P ratio. At a low N/P ratio corresponding to that in transfection at a lipid concentration below CMC, a net-like structure developed in which plasmid DNA was involved. A further increase in the N/P ratio, a large fibrous nanostructure of complexes, was also observed. Without DNA, these structures were not obtained. The cellular uptake mechanism of complexes using flow cytometry with inhibitors suggested that complexes with two different morphologies showed similar cellular uptake and uptake mechanism, macropinocytosis. Differences in transfection efficiency of the complexes may be explained by a large fibrous nanostructure inhibiting the cellular internalization of complexes or the release of DNA from macropinosomes into cytoplasm. Arg10-PEG-lipid/DNA complexes formed a favorable nanostructure for gene delivery, depending on the N/P ratio in water.