Potent preventive action of alpha-carotene against carcinogenesis: spontaneous liver carcinogenesis and promoting stage of lung and skin carcinogenesis in mice are suppressed more effectively by alpha-carotene than by beta-carotene

Although beta-carotene has been considered to be a key cancer preventive agent in green and yellow vegetables, other types of carotenoids, such as alpha-carotene, may also contribute to anticarcinogenic action, since these carotenoids usually coexist with beta-carotene and are detectable in human blood and tissues. In this study, we compared the inhibitory effect of natural alpha-carotene, obtained from palm oil, with that of beta-carotene on spontaneous liver carcinogenesis in C3H/He male mice. The mean number of hepatomas per mouse was significantly decreased by alpha-carotene supplementation (per os administration in drinking water at a concentration of 0.05%, ad libitum) as compared with that in the control group (P < 0.001, Student's t test). On the other hand, beta-carotene, at the same dose as alpha-carotene, did not show any such significant difference from the control group. Furthermore, we also compared the antitumor-promoting activity of alpha-carotene with that of beta-carotene against two-stage mouse lung carcinogenesis (initiator, 4-nitroquinoline 1-oxide; promoter, glycerol). alpha-Carotene, but not beta-carotene, reduced the number of lung tumors per mouse to about 30% of that in the control group (P < 0.001, Student's t test). The higher potency of the antitumor-promoting action of alpha-carotene compared to beta-carotene was confirmed in other experimental systems; e.g., alpha-carotene was also found to have a stronger effect than beta-carotene in suppressing the promoting activity of 12-O-tetradecanoylphorbol-13-acetate on skin carcinogenesis in 7,12-dimethylbenz[a]anthracene-initiated mice. These results suggest that not only beta-carotene, but also other types of carotenoids, such as alpha-carotene, may play an important role in cancer prevention.     

Close visual bridge inspection using a UAV with a passive rotating spherical shell

Today, robots are expected to be used for the inspection of infrastructures such as bridges. One important task in bridge inspection is to acquire clear images of its various parts for further damage evaluation. However, this task has not yet been completely realized because of the complexity of bridge structures. For this situation, a UAV with a passive rotating spherical shell (PRSS) that can easily maneuver while protecting itself is introduced. In this paper, we explain the development of the PRSS unmanned aerial vehicle (UAV) based on the design strategy. We then analyze its performance through simulated bridge inspection. Finally, we discuss the results of actual bridge experiments. The spherical shell has a size ( 0.95 m) and structure (fullerene) that is well‐suited for bridge inspection applications. It can also handle an impact equivalent to 2 m/s, which is more than the UAV's maximum flight speed. Test flight experiment also validated the characteristic of PRSS that shows a stable flight during disturbances. The image test also shows that the visual system can provide a full overhead view of the bridge. Likewise, it can detect a 0.1‐mm wide line that replicates the damage (e.g., a crack) from a position 0.5 m away and while the camera moves at 0.3 m/s. These characteristics have yielded a system that can acquire inspection images from critical parts of the bridge. An evaluation by third parties confirmed the effectiveness of the system. Further, the system satisfies the mandatory requirements of the Next Generation Robots for Social Infrastructure (NGRSI) program.     

Report on Microgravity Experiments of Dynamic Surface Deformation Effects on Marangoni Instability in High-Prandtl-Number Liquid Bridges

This paper reports an overview and some important results of microgravity experiments called Dynamic Surf, which have been conducted on board the International Space Station from 2013 to 2016. The present project mainly focuses on the relations between the Marangoni instability in a high-Prandtl-number (Pr=?67 and 112) liquid bridge and the dynamic free surface deformation (DSD) as well as the interfacial heat transfer. The dynamic free surface deformations of large-scale liquid bridges (say, for diameters greater than 10 mm) are measured with good accuracy by an optical imaging technique. It is found that there are two causes of the dynamic free surface deformation in the present study: the first is the time-dependent flow behavior inside the liquid bridge due to the Marangoni instability, and the second is the external disturbance due to the residual acceleration of gravity, i.e., g-jitter. The axial distributions of DSD along the free surface are measured for several conditions. The critical parameters for the onset of oscillatory Marangoni convection are also measured for various aspect ratios (i.e., relative height to the diameter) of the liquid bridge and various thermal boundary conditions. The characteristics of DSD and the onset conditions of instability are discussed in this paper.     

Improvement of impact strength and hydrolytic stability of PC/ABS blend using reactive polymer

Polycarbonate/acrylonitrile–butadiene–styrene (PC/ABS) blends have been used widely for specific applications such as in automotive interior and exterior parts, and for office automation equipment parts. This study was conducted to investigate the effects of a reactive polymer as a modifier on properties such as the impact strength of PC/ABS blends. A reaction between PC and maleic anhydride group cannot usually be expected because the end hydroxyl group of PC is capped with an end‐capping agent such as t‐butylphenol to improve PC properties such as fluidity, thermal resistance, and impact strength. However, a reactive polymer that has a maleic anhydride group reacts with the end hydroxyl group of PC hydrolyzed with metal salts. Results show that PC/ABS with a reactive polymer exhibits improved impact strength. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44550.     

Introduction of amino groups into the interlayer space of graphite oxide using 3-aminopropylethoxysilanes

Graphite oxide was silylated by 3-aminopropylethoxysilanes under various reaction conditions. Two types of layered materials were obtained when 3-aminopropyltriethoxysilane was reacted with graphite oxide. One obtained at lower temperatures was 3-aminopropyltriethoxysilane-intercalated graphite oxide with an interlayer spacing of 1.27 nm, in which amino groups of 3-aminopropyltriethoxysilane were bonded to hydroxyl groups of graphite oxide. At higher temperatures, silylation of graphite oxide occurred, giving a phase with larger interlayer spacing of 1.37 nm. Chemical reduction of graphite oxide to disordered carbon by amino groups occurred at the same time. Similar reactions occurred when 3-aminopropyldiethoxymethylsilane and 3-aminopropylethoxydimethylsilane were reacted and they were introduced into the interlayer space of graphite oxide. Large amounts of silicon, and accordingly amino groups, were introduced in graphite oxide when it was silylated by 3-aminopropyldiethoxymethylsilane because its reactivity for chemical reduction of graphite oxide was relatively lower than that of 3-aminopropyltriethoxysilane and additional silylation was possible. The amount of amino groups available for chemical adsorption of formaldehyde reached a very high value of 3.8 mmol/g for graphite oxide silylated by 3-aminopropyldiethoxymethylsilane.     

Growth of amorphous carbon nanotube from poly(tetrafluoroethylene) and ferrous chloride

The formation process of an amorphous carbon nanotube (α-CNT) from poly-(tetrafluoroethylene) using ferrous chloride was investigated by observing the TEM images of the isolated intermediates and conducting in situ TEM observation of its formation. These observations revealed unique features of the nanotube growth process through a series of steps; the growth of the core whisker, the deposition of amorphous carbon fragments onto the core whisker, and the disappearance of the core whisker, leaving the α-CNT. Such a unique process suggests a new method of controlling the carbon nano structure through the deposition of carbon over the core whisker template. The stable fluoride form of the core whisker is a key to preparing the amorphous carbon wall on its surface.     

Structural significance of the geminal-dimethyl group of (+)-trans-verbenyl acetate,sex pheromone mimic of the American cockroach

The significance of the geminal dimethyl group at C-6 of (+)-trans-veibenyl acetate (Ib), a sex pheromone mimic of the American cockroach, was investigated. Our interest was first directed to eliminating either methyl group of the geminal dimethyl group. Consequently, alcohols (IIIa and IVa) possessing a monomethyl group at C-6 were successfully obtained. Acetate (IVb) and propionate (IVc) of alcohol (IVa) possessing only a C-9 methyl group induced sex pheromonal activity at the 0.5 (IVb) and 0.02 mg (IVc) dose levels, respectively, while acetate (IIIb) of a alcohol (IIIa) with only C-8 methyl group was inactive. Alcohol (Va), which has an ethyl group at the C-6 instead of C-9 methyl, was also synthesized and converted into its acetate (Vb), which showed no activity. From these results, the significance of the dimethyl group is discussed relative to spatial requirements of the molecule for the receptor space. The M/F ratio in EAG was also evaluated for the synthesized esters. The M/F ratio index represented well the potency of pheromonal activity.     

Residual stress in particulate epoxy resin by X-ray diffraction

Residual stress in particulate epoxy resin was investigated by X-ray diffraction. Microdeformation of incorporated Al and α-SiO₂ crystal, which was induced by the residual stress, could be detected as a shift of X-ray diffraction peak. The residual stress at the interface between the adherend and the particulate epoxy resin was found to decrease with the increase of volume fraction of filler. It was shown that the difference in the thermal expansion coefficients between the adherend and the particulate epoxy resin is much more effective on residual stress than the increment of Young's modulus owing to the incorporation of filler. When epoxy resin was cured on the Al plate, incorporated particles were subjected to a tensile stress; while cured on polytetrafluoroethylene sheet, particles were subjected to a compressive stress. The incorporation of some inorganic particles is considered effective to reduce the residual stress.     

Mechanical clinching of ultra-high strength steel sheets and strength of joints

Ultra-high strength steel sheets having low ductility were joined by mechanical clinching with dies for control of metal flow. The diameter and depth of the die were modified to relieve concentration of deformation of the sheets for avoidance of the occurrence of sheet fracture. As the tensile strength of the steel sheets increased, the interlock decreased due to small metal flow. Two kinds of the ultra-high strength steel sheets having different ductility were used. The ultra-high strength steel sheets having large ductility were successfully joined using die having modified shape, whereas the sheets having small ductility were not joined. The static and fatigue strengths of the mechanically clinched joint were compared with those of the resistance spot welded joint. Although the static load of the mechanically clinched joint was smaller than that of the resistance spot welded joint in both tension-shearing and cross-tension tests, the fatigue load of the clinched joint was larger in the large number of cycles. It was found that mechanical clinching has superior fatigue strength due to the large yield stress of the sheets and relaxation of the stress concentration.     

Effects of urea–formaldehyde resin mole ratio on the properties of particleboard

The use of urea–formaldehyde (UF) resins with lower contents of free formaldehyde in the board industry has led to products with very low emissions of formaldehyde. This study gives a detailed account of the influence on the mechanical and physical properties of the particleboard using UF resins with different mole ratios of formaldehyde:urea within the range 0.97–1.27. The mole ratio influenced not only the thickness swelling (TS) and water absorption (WA) but also the internal bond strength (IB) and the modulus of rupture (MOR) if the manufacturing process was optimized. The investigation revealed clearly that at mole ratios of formaldehyde giving the emission class El the MOR, IB, TS, and WA of particleboard deteriorated. Compensation for the deterioration could be provided through a higher dosage of resin or through the modification of UF resin. However, both alternatives meant that the product would be more expensive.