A Search for Water Masers in the Saturnian System

We searched for H2O 6(1,6)-5(2,3) maser emission at 22.235 GHz from several Saturnian satellites with the Nobeyama 45m radio telescope in May 2009. Observations were made for Titan, Hyperion, Enceladus and Atlas, for which Pogrebenko et al. (2009) had reported detections of water masers at 22.235 GHz, and in addition for Iapetus and other inner satellites. We detected no emission of the water maser line for all the satellites observed, although sensitivities of our observations were comparable or even better than those of Pogrebenko et al.. We infer that the water maser emission from the Saturnian system is extremely weak, or sporadic in nature. Monitoring over a long period and obtaining statistical results must be made for the further understanding of the water maser emission in the Saturnian system.Comment: 8 pages, 2 figures, accepted for publication in PASJ (Letter

Rac1 and Stathmin but Not EB1 Are Required for Invasion of Breast Cancer Cells in Response to IGF-I

Cell migration is considered necessary for the invasion that accompanies the directional formation of the cellular protrusions termed lamellipodia. In invasive breast cancer MDA-MB-231 cells, lamellipodia formation is preceded by translocation of the actin cytoskeletal regulatory protein WAVE2 to the leading edge. WAVE2 translocation and lamellipodia formation require many signaling molecules, including PI3K, Rac1, Pak1, IRSp53, stathmin, and EB1, but whether these molecules are necessary for invasion remains unclear. In noninvasive breast cancer MCF7 cells, no lamellipodia were induced by IGF-I, whereas in MDA-MB-231 cells, Rac1, stathmin, and EB1 were overexpressed. Depletion of Rac1 or stathmin by small interfering RNA abrogated the IGF-I-induced invasion of MDA-MB-231 cells; however, depletion of EB1 did not, indicating the necessity of Rac1 and stathmin but not EB1 for invasion. The signaling pathway leading to cell invasion may not be identical but shares some common molecules, leading to cell migration through lamellipodia formation

Life Cycle of the Soybean Aphid Aphis glycines Matsumura, in Japan

The soybean aphid Aphis glycines MATSUMURA is the main sap-sucking pest on soybeans Glycine max. In Japan, it is distributed from Hokkaido to Kyushu (Sakai, 1949); abroad, it is found in Korea, China, Taiwan, Thailand, Malay (Paik, 1965), the Phillipines (Takahashi, 1966), and India (Raychaudhuri et al., 1980). In addition to soybeans, wild Glycine species are known to be a secondary host. Matsumura reported this aphid species on soybean (1917a) and in the same year recorded that its eggs over-wintered on plants belonging to the wild pea family (1917b). Shindo (1928, 1932) originally identified Kitsunenomago Justicia procumbens and purplish amaranth Amaranthus blitum as primary hosts, but later retracted and reported that the eggs over-winter in the roots of the Japanese chaff flower Acyranthes japonica (1941). However, Sakai (1949, 1950a, b) showed in greenhouse studies that this aphid does not over-winter in the chaff flower, and concluded that the species found on chaff flower was actually Aphis justiciae SHINJI which Shindo (1928) considered to be the same as Aphis glycines. While the controversy in Japan about the primary host remained unresolved, in China it was reported by Wang et al. (1962) that the eggs over-wintered in the Dahurian buckthorn Rhamnus davurica of the buckthorn family. Zhang and Zhong (1982) subsequently established that several of the 15 species in the genus Rhamnus found in China were primary hosts. In the reports from China, only the body color and the number of secondary sensilla of the third antennal segment of gynopara were reported, and no mention was made of the morphs on the primary host. Since 1981, our field surveys and greenhouse studies have focused on the life cycle and morphs on primary hosts in the genus Rhamnus, the results of which are reported here.Originating text in Japanese.Citation: Takahashi, Shigeru, Inaizumi, Mitsumaru, Kawakami, Koji. (1993). Life Cycle of the Soybean Aphid Aphis glycines Matsumura, in Japan. Japanese Journal of Applied Entomology and Zoology, 37, 207-212

Mutual Interaction between Collectors and Frothers in Flotation

The behavior of a frother in flotation was investigated from the viewpoint of the mutual interaction between a collector and a frother. The floatability of galena and the interfacial tensions of the mercury-solution interface were measured using ethyl and amyl xanthates and normal alcohols containing 1～5 carbon atoms. The floatability test showed that butyl and amyl alcohols were favourable as a frother. The interfacial tension mesurements verified that alcohol molecules can adsorb on the mercurysurface only in coexistence with xanthate molecules in a solution. The degree of the coadsorption of alcohol molecule with xanthate molecule on mercury increases with increasing the number of carbon atoms in the alkyl chain of alcohol. It was clarified from the discussion of the infrared-spectroscopic study for the reagents that the value of ln(ν-ν₀) based on the shift of CH₃ stretching vibration was closely related to the degree of the coadsorption of a frother with a collector at the mineral-solution interface. Furthermore, the value of ln (ν－ν₀) was shown to be one of the measures indicating the choice of their proper combination

On the Critical Flotation Condition of a Sulfide Mineral Having Two Kinds of Positive Sites for the Anionic Collector and Depressant Adsorption

The critical flotation condition for the sulfide mineral having two kinds of positive sites was discussed from the viewpoint of the competitive adsorption of anionic collectors and depressants by means of statistical mechanics and chemical thermodynamics. On the basis of the statistical mechanics as to the collector-depressant equilibria, the familiar Barsky relation was derived for the double positive site mineral. The Barsky constant can be dependent on all of the collector and depressant adsorptions for each kind of reaction site on the mineral surface according to their adsorption property. In the chemical thermodynamics investigation, the chalcopyrite (CuFeS₂)-xanthatehydroxyl ion system was considered. The chemical affinities of the xanthate ion and the hydroxyl ion onto the positive sites of CuS and FeS, respectively, were calculated, using thermodynamical data for the system. Consequently, it was ascertained that the depressing action of the hydroxyl ion for chalcopyrite was mainly connected with the adsorption of the hydroxyl ion onto the positive site due to FeS, while the collecting mechanism of the xanthate ion for the same mineral is closely related to the adsorption of the xanthate ion onto the positive site due to CuS. The chalcopyrite (CuFeS₂)-xanthate-cyanide ion and hydroxyl ion system was also considered in a similar manner. The flotation-nonflotation condition of chalcopyrite was able to be determined by considering the xanthate adsorption on the positive site due to CuS and the cyanide ion adsoprtion on the one due to FeS