Development of Breakup Model for Large Eddy Simulation of Diesel Spray

Diesel spray is injected at high pressure. So, upper stream region of spray is high Weber number condition. However, even if the fuel is injected at high pressure, the downstream region of spray is corresponding to relatively low Weber number condition. Thus, KH （Kelvin-Helmholtz） model modeled for high Weber number conditions and MTAB （modified Taylor analogy breakup） model are used for primary and secondary breakup processes respectively. This study is focused on the development of new hybrid breakup model The calculations are performed by LES （large eddy simulation） incorporated into KIVA code. LES of non-evaporating diesel spray are performed using KH ＆ RT （Rayleigh-Taylor） model, MTAB model and KH-MTAB model. Then, LES with these models were compared with experimental results. As the result, the availability of KH-MTAB model is showed. It is found that KH-MTAB is good agreement with experimental results of penetration and SMD （Sauter mean diameter） in relatively low density conditions.     

Architecture of nanostructured polymers by segregated domain crosslinking of block‐graft copolymer micelles

Polystyrene‐block‐polyisoprene (PS‐block‐PI; high 3,4‐structure) diblock copolymer was prepared by living anionic polymerization. For transfer into a reactive intermediate, the hydroxylation of the double bonds of PI block was achieved by hydroboration, followed by oxidation. Esterification of the hydroxy‐derivative with stearoyl chloride or decanoyl chloride resulted in block‐graft copolymers composed of PS (flexible chain)‐grafted long alkane (stretched chains). After partial chloromethylation of PS block copolymer, photofunctional N,N‐diethyldithiocarbamate (DC) groups were introduced into such pendant sites by reaction with the corresponding sodium salt. We studied the self‐assemblies of photofunctional block‐graft copolymers in a selective solvent, such as heptane, and constructed nanostructured polymers by crosslinking PS cores under UV irradiation. © 2001 Society of Chemical Industry     

Classification of heavy-metal toxicity by human DNA microarray analysis

Microarray technology is proving to be a useful tool to classify undefined environmental toxicants, to investigate underlying mechanisms of toxicity, and to identify candidate toxicant-specific genetic markers by examining global effects of putative toxicants on gene expression profiles. The aim of this study was to evaluate the toxicities of six heavy metals through the comparison with gene expression patterns induced by well-known chemicals. For this purpose, we first identified the genes altered specifically in HepG2 under the exposure of 2,3-dimethoxy-1,4-naphthoquinone (DMNQ), phenol, and N-nitrosodimethylamine (DMN), which were selected as the model chemicals, using DNA microarray. On the basis of the expression profiles of these genes, toxicities of six heavy metals, arsenic, cadmium, nickel, antimony, mercury, and chromium, were evaluated. The specific gene alteration and hierarchical clustering revealed that biological action of six heavy metals was clearly related to that of DMNQ which has been reported to be a reactive oxygen species (ROS) generating chemical and which induced the genes associated with cell proliferative responses. These results suggest that cell proliferative responses which are probably caused by ROS are a major apparent biological action of high-dose heavy metals, supporting the previous reports. Overall, a mechanism-based classification by DNA microarray would be an efficient method for evaluation of toxicities of environmental samples.     

Melt electrospinning from poly(L‐lactide) rods coated with poly(ethylene‐co‐vinyl alcohol)

Rodlike poly(L ‐lactide) (PLLA) samples coated with poly(ethylene‐co‐vinyl alcohol) (EVOH) were made. Fibers were produced from these rodlike samples by using a melt electrospinning system equipped with a laser irradiating device, and the effects of EVOH content and the processing parameters of the melt electrospinning on fiber diameters were investigated. We also studied the fiber formation mechanism from the rods during the laser melt electrospinning process. The following conclusions were reached: (i) coating of EVOH on PLLA rods has a remarkable effect on decreasing fiber diameter from 3 μm to around 1 μm; (ii) increases in the electric field strength and temperature of spinning space decrease the average diameter of fibers produced from pure PLLA rods, and longer collector distance leads to lager PLLA fiber diameter; and (iii) the migration of PLLA component from the core to the surface of electrospun fibers takes place during the fiber formation process. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Effects of emulsifiers on the oxidative stability of soybean oil TAG in emulsions

The effects of two types of commercial emulsifiers, sucrose FA esters and polyglycerol FA esters, on the oxidation of soybean oil TAG-in-water emulsions were studied. Both emulsifiers influenced the oxidative stability of soybean oil TAG in the emulsion, but they had little effect on the oxidation of TAG in bulk phase. When the TAG were dispersed with sucrose esters having the same FA composition, the oxidative stability increased as their hydrophilic-lipophilic balance (HLB) increased. On the other hand, when the HLB was the same, the oxidative stability increased with increasing acyl chain length of the FA esterified on sucrose ester. However, the effect of the polyglycerol ester could not be explained by the relationship with HLB or the acyl composition. When the stability of TAG in emulsion was compared under the same concentrations of TAG, emulsifier, and oxidation inducer, the TAG dispersed with sucrose esters were oxidatively less stable than with polyglycerol esters. Analysis of the emulsion droplet size suggested that the lower oxidative stability of TAG dispersed with sucrose esters was partly due to their relatively smaller droplet sizes.     

Wisteria floribunda Agglutinin-Positive Mac-2 Binding Protein as a Screening Tool for Significant Liver Fibrosis in Health Checkup

Chronic liver disease is generally widespread, and a test for screening fibrotic subjects in a large population is needed. The ability of Wisteria floribunda agglutinin-positive mac-2 binding protein (WFA⁺-M2BP) to detect significant fibrosis was investigated in health checkup subjects in this research. Of 2021 health checkup subjects enrolled in this prospective cross-sectional study, those with WFA⁺-M2BP ≥ 1.0 were defined as high risk. Liver fibrosis was evaluated using magnetic resonance elastography (MRE) in subjects with high risk. The primary outcome was the positive predictive value (PPV) of WFA⁺-M2BP for significant fibrosis (liver stiffness ≥ 2.97 kPa by MRE). This trial was registered with the UMIN clinical trial registry, UMIN000036175. WFA⁺-M2BP ≥ 1.0 was observed in 5.3% of the 2021 subjects. The PPV for significant fibrosis with the threshold of WFA⁺-M2BP at ≥1.0, ≥1.1, ≥1.2, ≥1.3, ≥1.4, and ≥1.5 was 29.2%, 36.4%, 43.5%, 42.9%, 62.5%, and 71.4%, respectively. A WFA⁺-M2BP of 1.2 was selected as the optimal threshold for significant fibrosis among high-risk subjects, and the PPV, negative predictive value, sensitivity, and specificity for significant fibrosis were 43.5%, 84.0%, 71.4%, and 61.8%, respectively. WFA⁺-M2BP ≥ 1.2 was significantly associated with significant fibrosis, with an odds ratio (OR) of 4.04 (95% confidence interval (CI): 1.1–16, p = 0.04), but not FIB-4 ≥ 2.67 (OR: 2.40, 95%CI: 0.7–8.6, p-value = 0.2). In conclusion, WFA⁺-M2BP is associated with significant fibrosis and could narrow down potential subjects with liver fibrosis. The strategy of narrowing down fibrosis subjects using WFA⁺-M2BP may be used to screen for fibrotic subjects in a large population.     

Direct length comparison between regular crystalline lattice and SEM standard grating using dual tunneling unit STM

This paper presents a potential image processing method for calibrating the in-plane geometrical distortion of a scanning tunneling microscope (STM) image using a regular crystalline lattice, describes the assessment evaluation of comparative length measurement in the range of about 1 micrometer using a regular crystalline lattice as a reference scale and a dual tunneling unit-STM (DTU-STM) as a detector, and shows the results of direct length comparison between a scanning tunneling microscope (SEM) standard grating, whose pitch is 240 nm, and a regular crystalline lattice using a DTU-STM. The method is based on two-dimensional fast Fourier transform (FFT) analysis. The DTU- STM with one X-Y stage and two tunneling units independently controlled in the Z-axis direction has been utilized for comparative length measurement. To improve the measurement accuracy, the present method is used to process the raw images obtained from the DTU-STM. The results of assessment experiments, in which the cleaved surface of highly oriented pyrolytic graphite (HOPG) is used as a reference scale for measurement of lengths on the order of 1 micrometer, demonstrate the feasibility of the present image processing method and the comparative length measurement with sub-nanometer resolution using the DTU- STM. The value of the SEM standard grating pitch, which obtained from the direct length comparison with HOPG lattice spacing using the DTU-STM, was coincided with the value obtained from the conventional diffraction method within a error of 2 %.     

Homogeneous ZrO2–Al2O3 Composite Prepared by Nano-ZrO2 Particle Multilayer-Coated Al2O3 Particles

ZrO₂–Al₂O₃ nanocomposite particles were synthesized by coating nano-ZrO₂ particles on the surface of Al₂O₃ particles via the layer-by-layer (LBL) method. Polyacrylic acid (PAA) adsorption successfully modified the Al₂O₃ surface charge. Multilayer coating was successfully implemented, which was characterized by ξ potential, particle size. X-ray diffraction patterns showed that the content of ZrO₂ in the final powders could be well controlled by the LBL method. The powders coated with three layers of nano-ZrO₂ particles, which contained about 12 wt% ZrO₂, were compacted by dry press and cold isostatically pressed methods. After sintering the compact at 1450°C for 2 h under atmosphere, a sintered body with a low pore microstructure was obtained. Scanning electron microscopy micrographs of the sintered body indicated that ZrO₂ was well dispersed in the Al₂O₃ matrix.     

Efficient production of the C-terminal domain of secretory leukoprotease inhibitor as a thrombin-cleavable fusion protein in Escherichia coli

We have developed a high-level production system for the C-terminaldomain of secretory leukoprotease inhibitor (SLPI) to investigateits pharmacological activities. A gene for the C-terminal domainof SLPI, (Asn55-AlalO7)SLPI, was constructed from chemicallysynthesized deoxyoligonucleotides. It was fused to a gene forthe N-terminal portion of human growth hormone via a DNA sequenceencoding Leu-Val-Pro-Arg, which can he cleaved by thrombin.The fused gene was expressed in Escherichia coli under the controlof a trp promoter, and the fusion protein was obtained as aninclusion body. After sulfonation of the cysteine residues,the sulfonated fusion protein was cleaved at the desired siteby thrombin. Sulfonated (Asn55-Ala107)SLPI was refolded in Trisbuffer containing reduced and oxidized glutathione. The resulting(Asn55-Ala107) SLPI was purified by cation-exchange chromatographyand reverse-phase high performance liquid chromatography. Thefinal yield was 50 mg/l culture. (Asn55-Ala107)SLPI was as activeagainst elastase as, but had less trypsin inhibitory activitythan, native SLPI. This system is suitable for the large-scaleproduction of the C-terminal domain of SLPI, which is an elastase-specificinhibitor.     

Mechanical Properties of Woodceramics: A Porous Carbon Material

The mechanical properties of woodceramics, which are new porous carbon materials utilizing the natural structure of wood, were investigated. The effects of burning temperature and amount of impregnated phenol resin on Young's modulus, compressive strength and fracture toughness were measured. The fracture morphology was then observed, and simplified mechanical models of the woodceramics were discussed to explain the mechanical properties. The fracture was initiated at the cell walls that were located in vertical direction against the applied stress. The effect of impregnated phenol resin on the Young's modulus and the compressive strength was reasonably explained by a wall-bending model.