Growth monitoring and classification of rice fields using multitemporal RADARSAT-2 full-polarimetric data

Spaceborne synthetic aperture radar (SAR) can be used for agricultural monitoring. In this study, three single-polarimetric and four full-polarimetric observation data sets were analysed. A rice paddy field in northern Japan was used as the study site; the data for this site were obtained using RADARSAT-2, which carries a full-polarimetric C-band SAR. Soybean and grass fields were also present within the paddy fields. The temporal change in the backscattering coefficient of the rice paddy fields for the single-polarization data agreed with the temporal change obtained for a rice growth model based on radiative transfer theory. A three-component decomposition approach was applied to the full-polarimetric data. With each rice growth stage, the volume scattering component ratio increased, whereas the surface scattering component ratio generally decreased. The soybean and grass fields showed a smaller double-bounce scattering component than the rice fields for all the acquired data. The results of this study show that multitemporal observation by full-polarimetric SAR has great potential to be utilized for estimating rice-planted areas and monitoring rice growth.     

Arsenic trioxide inhibits growth of human T-cell leukaemia virus type I infected T-cell lines more effectively than retinoic acids

Adult T-cell leukaemia (ATL) is difficult to cure using conventional therapies. Recently the therapeutic possibility of retinoic acids (RA) has been reported. In this study, suppression of in vitro growth of human T-cell leukaemia virus type I (HTLV-I) infected T-cell lines and fresh ATL cells by arsenic trioxide (As2O3) were evaluated by comparison with a series of RA derivatives. Proliferation of four HTLV-I-infected T-cell lines was significantly reduced within 72 h by 1.0 micromol/l As2O3. Growth of two out of four HTLV-I-infected T-cell lines was also inhibited by 1.0 micromol/l RA, but to a lesser extent than by As2O3. The mechanism of this growth inhibition was due to the induction of apoptosis. Apoptosis was also induced in fresh ATL cells from patients by AS2O3, but far less by RA. As described in patients with acute promyelocytic leukaemia, 1.0 micromol/l of As2O3 can be safely achieved in the serum of patients; however, it is difficult to maintain this concentration of RA. In conclusion, As2O3 has therapeutic potential for the treatment of ATL and may be far more clinically beneficial than RA.     

Preparation of copolymer of styrene with hemin and its functional property as cyanide ion exchanger

Summary Copolymers of hemin and styrene with different hemin contents were prepared by radical polymerization, using pyridine as the solvent and ,-azobisisobutyronitrile as the initiator. It was found that the obtained copolymers are insoluble in aqueous solvents and have function as cyanide ion exchanger.     

Oxochloromolybdenum(V)tetraphenylporphyrin complex-containing polymer as a phosphate ion exchanger

Summary Oxochloro(5,10,15,20-tetraphenylporphyrinate)molybdenum (V) was physically entrapped into poly (styrene) by lyophilizing a benzene solution including both complex and polymer. The functional ability of the obtained complex-containing resin to adsorb H₂PO₄ ^– from an aqueous solution was investigated in the presence of various anions. It was found that the selectivity of the resin for H₂PO₄ ^– is superior to those of conventional anion exchangers.     

On the expected behaviors of the Dijkstra's shortest path algorithm for complete graphs

Shortest path, shortest spanning tree, complete graph, number of comparisons, expected complexity