Conformational analyses of periplanone analogs by molecular mechanics calculations

Conformational parameters of pheromonally active analogs (1 and 2) of periplanones, the sex pheromones of the American cockroach, were investigated by molecular mechanics calculations. They existed in several conformers with small energy differences. These results were supported by NMR analysis. The structural features of the conformers of the analogs were compared with X-ray structures of periplanones.     

Acute accidental overdosage of haloperidol in children

Antagonistic action between 5-fluorouracil (5-FU) and riboflavin (RF) was investigated. The growth of Arthrobacter sp. was inhibited by 5-FU at 5 x 10(-5) M, and the inhibition was reversed by RF at 5 x 10(-5) M. 5-FU-resistant mutants of Arthrobacter sp. were isolated and excreted RF in relatively high yields, but the wild-type strain excreted no RF. One of the mutants, strain No. 28-35, produced 223.2 micrograms ml-1 of RF in culture medium at 4 days.     

Submillimeter wave esr and far infrared spectroscopy measurements of CuGeO3

Submillimeter wave ESR and far infrared transmission measurements of first inorganic spin-Peierls system CuGeO₃ have been performed using the single crystals. Our new results are discussed in connection with the magnetic properties of the spin-Peierls systems and the recent neutron measurements of CuGeO₃.     

Synthesis and properties of polyhydrazides and polyoxadiazoles containing pyridine rings in the polymer backbone

Summary Polyhydrazides containing pyridine rings in the backbone were synthesized by interfacial or solution polycondensation from 2,5-pyridine dicarboxylic acid and three dihyrazides or hydrazine. Heating conditions suitable for the formation of polyoxadiazoles by dehydration of the polyhydrazides were studied by infrared analysis. The polyoxadiazoles formed were thermally stable but poorly soluble. The polyhydrazides were soluble and could take up cobalt (II) ions. The potential applicability of the polyhydrazides to a reverse osmosis membrane was demonstrated.     

Behavior of polymers containing spiroorthoester or bicycloorthoester structure under EB and X-ray irradiation conditions

Reaction behavior of spiroorthoester and bicycloorthoester to EB and X-ray irradiations has been studied on the basis of infrared spectroscopic analysis. The polymers containing these functional groups showed markedly high sensitivity to EB and X-ray. The formations of C?O and ? OH after exposure indicate that these functional groups react through ring opening even in the absence of any cationic catalyst. In the high energy-induced reaction, sensitivity and post-irradiation polymerization effect were found to be greatly influenced by the polymer structure, different from those observed in the cation-induced reaction.     

Microbial processes responsible for nitrous oxide production from acid soils in different land-use patterns in Pasirmayang,central Sumatra,Indonesia

The most probable number (MPN) method and dicyandiamide (DCD), an autotroph-specific inhibitor, were used to identify microbial processes that produced N₂O in acid soils. Nitrous oxide production was investigated in six sites in four different land-use patterns at Pasirmayang in Jambi province, in Sumatra, Indonesia, using soils collected in October 1999, March 2000 and June 2000. The six sites were primary forests (P1 and P2), loggedover forests (L2), a young rubber plantation established after forest had been logged and burned in March 1998 (L1), a plantation of Gmelina arborea established after logging and burning of forest in August 1996 (O), and a rubber plantation of a small landholder established in 1993 (R). Very small numbers of autotrophic ammonia oxidizers and autotrophic nitrite oxidizers were detected. Heterotrophic nitrifiers were detected at all sites, with the highest MPNs at L1 and L2. In incubation experiments, the emission of N₂O from soils increased at all six sites after adding citrate, a substrate for heterotrophic nitrifiers. No correlation appeared between denitrification activity and N₂O flux. We conclude that heterotrophic nitrifiers are the main microbial contributors to N₂O emission from acid soils in Pasirmayang, Jambi.