Inflammogenic effect of well-characterized fullerenes in inhalation and intratracheal instillation studies

Background

We used fullerenes, whose dispersion at the nano-level was stabilized by grinding in nitrogen gas in an agitation mill, to conduct an intratracheal instillation study and an inhalation exposure study. Fullerenes were individually dispersed in distilled water including 0.1% Tween 80, and the diameter of the fullerenes was 33 nm. These suspensions were directly injected as a solution in the intratracheal instillation study. The reference material was nickel oxide in distilled water. Wistar male rats intratracheally received a dose of 0.1 mg, 0.2 mg, or 1 mg of fullerenes and were sacrificed after 3 days, 1 week, 1 month, 3 months, and 6 months. In the inhalation study, Wistar rats were exposed to fullerene agglomerates (diameter: 96 ± 5 nm; 0.12 ± 0.03 mg/m³; 6 hours/days for 5 days/week) for 4 weeks and were sacrificed at 3 days, 1 month, and 3 months after the end of exposure. The inflammatory responses and gene expression of cytokine-induced neutrophil chemoattractants (CINCs) were examined in rat lungs in both studies.

Results

In the intratracheal instillation study, both the 0.1 mg and 0.2 mg fullerene groups did not show a significant increase of the total cell and neutrophil count in BALF or in the expression of CINC-1,-2αβ and-3 in the lung, while the high-dose, 1 mg group only showed a transient significant increase of neutrophils and expression of CINC-1,-2αβ and -3. In the inhalation study, there were no increases of total cell and neutrophil count in BALF, CINC-1,-2αβ and-3 in the fullerene group.

Conclusion

These data in intratracheal instillation and inhalation studies suggested that well-dispersed fullerenes do not have strong potential of neutrophil inflammation.     

Pressure-dependence of dielectric relaxation time in poly(propylene glycol) and its application to high-pressure viscosity estimation

Dielectric permittivity and loss of poly(propylene glycol) with different molecular weights (400–3000) and terminal groups (OH and CH₃) have been measured in the frequency range of 100 Hz to 1.5 MHz. Measurements were conducted over the temperature range 202–293 K under atmospheric pressure and 283–320 K under pressure up to 600 MPa. Two relaxation processes, one with strong absorption in the high-frequency region (α-relaxation) and the other a weak process in the low-frequency region (α′-relaxation), were observed for the OH-terminated samples having molecular weights above 2000 and for all the CH₃-terminated samples. Most of the experimental data under high pressure showed a nonlinear decrease in the logarithm of the frequency of maximum dielectric loss with increasing pressure. The pressure-dependence of the dielectric relaxation time of the α-process was analyzed by several models based on the free-volume concept. The regression results of dielectric relaxation time as a function of pressure were applied to the estimation of high-pressure viscosity. The predicted viscosity showed relatively good agreement with viscosity data obtained from a falling-sphere viscometer.     

Porcine artery elastin preparation reduces serum cholesterol level in rats

The effect of porcine artery elastin on serum cholesterol level was investigated in rats fed a cholesterol-free diet. Rats were fed for 4 weeks, with a diet (ED) containing 15% casein and 5% of porcine artery elastin in comparison with a diet (CD) containing 20% casein. The total serum and non-HDL-cholesterol concentrations were lower (P < 0.001) in ED-fed group than the CD-fed group at the end of the experiment. Caecal propionate concentration and Bifidobacterium and Lactobacillus population were higher (P < 0.05) in ED-fed group than the CD-fed group. The results of this study suggest that porcine artery elastin could be considered as a functional dietary protein with hypocholesterolaemic ability. Favourable amino acid composition and lysine derived cross links may at least be partially responsible for the hypocholesterolaemic ability of ED. Moreover, the higher caecal propionic acid concentration in the ED-fed group may have suppressed the cholesterol synthesis in the liver, and reduced the serum cholesterol level.     

Purple potato flake reduces serum lipid profile in rats fed a cholesterol-rich diet

The effect of purple potato flake on cholesterol metabolism was investigated in rats fed a high-cholesterol diet. The hypocholesterolemic action of dietary purple potato flake might be related with caecal fermentation and steroid excretion due to the phosphorus and polyphenols including anthocyanin.     

Degree of comonomer inclusion into lamella crystal for propylene/olefin copolymers

Copolymers of propylene with ethylene, butene-1, hexene-1, and octene-1 were synthesized with isospecific metallocene catalyst system. Crystalline structure of the melt-crystallized samples was investigated from the viewpoint of the comonomer location in a solid-state of the copolymers, using the fuming nitric acid (FNA) etching technique followed by ¹³C NMR spectrum measurement. It was found that the copolymers were oxidatively degraded with FNA at 50 °C and the residue after etching was corresponding to the lamella crystal of the original state. ¹³C NMR spectrum of the residue revealed that all kinds of comonomer used here were located not only in the amorphous phase but also in the crystalline core. Among comonomers, butene-1 is favorably incorporated in the crystalline phase with the expansion of the crystal lattice, and the amount of comonomer in the crystal is comparable with that in the amorphous phase. Ethylene, hexene-1 and octene-1 were also found to be included into the crystal, but the degree of inclusion in the crystal was much less than that of butene-1.

Considering both the continuous increase of the weight loss and the saturation of the molecular weight decrease of the residue during an etching time-course, a plausible mechanism for the FNA degradation of the propylene copolymers was proposed.     

Punching of small hole of die-quenched steel sheets using local resistance heating

A punching process of a small hole in a die-quenched steel sheet having high strength using local resistance heating of a shearing zone was developed to decrease the punching load. Uniform temperature in the circular shearing zone of the hole was obtained by optimising heating conditions for a pair of rectangular electrodes. The punch load and the burnished surface area for the heating at 500 °C were about 1/3 smaller and 2 times larger than those for the cold punching, respectively, and the occurrence of delayed fracture around the punched hole was prevented by the heating above 500 °C.     

Noninvasive pump flow estimation of a centrifugal blood pump

A flow rate estimating method was investigated for a centrifugal blood pump developed in our institute. The estimated flow rate was determined by the power consumption, the rotating speed of the motor, and the hematocrit value. The power consumption and the rotating speed of the motor were measured with a wattmeter. The examinations were performed in a closed mock loop filled with goat blood with hematocrit values of 21.5%, 28%, 34%, and 42%. Measured values of blood viscosity were 2.47, 3.09, 3.71, and 5.07 mPa.s at a share rate of 37.5/s, respectively. A linear correlation between the power consumption and the pump flow rate was observed in all hematocrit values. But variations in hematocrit caused a difference in the flow rate up to 1.1 L/min at the same power consumption and rotating speed. Effects of blood viscosity on the flow estimation were corrected by the hematocrit value. The value of the coefficient of determination, R2, between the estimated flow rate and the measured flow rate was 0.988. These results may indicate that the flow estimating method calculated by the power consumption of the motor, the rotating speed, and the hematocrit value is useful in the clinical situation.     

A biologically plausible neural network for motion detection

A neural network model is proposed that detects the actual velocity vector of an object by using local motion signals detected by local motion detectors. First, the computational theory to obtain the actual velocity vector of a rigid object is described. Then a neural network is shown that implements the theory. The neural network model is constructed by two layers: a local velocity vector extraction layer and an integration layer. Many velocity vectors of points on a moving object are detected by local detectors in the local velocity vector extraction layer. These local velocity vectors are integrated in the integration layer in order to obtain the actual velocity vector of the object. The computational processing pathway of the proposed model is similar to the motion processing pathway of visual stimulus in the actual nervous system.     

Metal composition of Y2O3:Eu powder evaluated using particle analyzer

Y₂O₃:Eu red phosphor powder was synthesized with powders of metal–ethylenediaminetetraacetic acid (EDTA) complexes as a starting material. The compositional analysis of each metal–EDTA complexes particle and Y₂O₃:Eu particle was performed using a particle analyzer. In this study, first, the particles of a mixture of Y– and Eu–EDTA complexes were obtained by a spray drying method from solution consisting of Y– and Eu–EDTA$NH₄. Then, the metal–EDTA complex powder was fired in obtaining the Y₂O₃:Eu red phosphor. The metal composition of each particle was scattered for the powder of the metal–EDTA mixture, while it became narrow for the Y₂O₃:Eu powder. The intensity of cathodoluminescence obtained from the Y₂O₃:Eu powder increased with increasing the fired temperature. In addition, the maximum intensity was obtained from the sample with xZ0.12 for Y_2KxO₃:Eu_x.     

Propagation characteristics of neutrons leaking from the accelerator facilities

In this study spatial and time distribution of neutrons leaking from Hokkaido University 45 MeV Electron Linac facility have measured and compared with the Monte Carlo simulations. The neutron transport processes inside and outside the facility building has been simulated using MCNP. The neutrons have measured by BF3 counters and 3He counters with polyethylene moderators up to the distance of 330 m from the facility. The spatial distribution of ambient dose equivalent converted from the counts has been compared with the simulation. The distribution estimated from the counts by the BF3 counter has been shown fairly good agreement with the calculation. The spatial distribution of counts obtained at the 45 MeV Electron Linac facility has been compared with that obtained at the Fusion Neutronics Source (FNS) facility of JAERI. The difference between the propagation characteristics of neutrons leaking from those facilities has been discussed.