Synthetic studies on oligomycins. Enantiospecific synthesis of the oligomycin B spiroketal portion and establishment of the absolute stereochemistry of oligomycin B

The enantiospecific synthesis of the oligomycin B degradation product 2, corresponding to the C19–C34 spiroketal portion, has been achieved by sequential coupling of the C19–C21, C22–C27, and C28–C34 subunits, establishing the absolute stereochemistry of oligomycin B.     

Two-Dimensional Cellular Automata for Pseudo-Random Pattern Generators and for Highly Secure Stream Ciphers

Pseudo-random properties of a class of two-dimensional (2-D) 5-neighborhood cellular automata (CA), built around nonlinear (OR, AND) and linear (XOR) Boolean functions are studied. The site values at each step of the 2-D CA evolution are taken in parallel and form pseudo-random sequences, which satisfy the criteria established for pseudo random number generator (PRNG): long period, excellent random qualities, single bit error propagation (avalanche criteria), easy and fast generation of the random bits. A block-scheme for secure Stream Cipher based on 2-D CA is proposed. The 2-D CA based PRNG algorithm has simple structure, use space-invariant and local interconnections and can be easily realized in very large scale integration or parallel optoelectronic architectures.     

Differences in the yields of polycyclic aromatic hydrocarbons by pressurized liquid extraction and the Japanese official method

To improve the extraction of polycyclic aromatic hydrocarbons (PAHs) from sediment samples, we optimized the conditions of pressurized liquid extraction (PLE). The yields increased as the extraction temperature increased from 100 to 190 degrees C, but the effect of increasing pressure (from 15 to 20 MPa) was small. Parameters of 190 degrees C and 20 MPa, near the maximum of the equipment, gave the highest yield. Under these conditions, the yields of 17 PAHs were 1.5 - 34 times those obtained by the Japanese official method (shaking and ultrasonic extraction with acetone at room temperature).     

Accurate Quantification of Polycyclic Aromatic Hydrocarbons in Environmental Samples Using Deuterium-labeled Compounds as Internal Standards

For the accurate quantification of polycyclic aromatic hydrocarbons (PAHs) in environmental samples by isotope-dilution mass spectrometry (IDMS) and gas chromatography-mass spectrometry (GC-MS), we used deuterium-labeled PAHs (D-PAHs) as internal standards for microg g(-1)-level certified reference materials and corresponding calibration solutions. Although pressurized liquid extraction (PLE) causes significant biases in the analytical results for ng g(-1)-level samples (2.4 - 15%), biases in the analytical results by PLE (190 degrees C, 20 MPa, 2 cycles) were small (<2.3%) and negligible for microg g(-1)-level samples when expanded uncertainty (coverage factor k = 2) was considered.     

Bimeasure algebras on locally compact groups

For locally compact groups G and H, let BM(G, H) denote the Banach space of bounded bilinear forms on C₀(G) × C₀(H). Using a consequence of the fundamental inequality of A. Grothendieck. a multiplication and an adjoint operation are introduced on BM(G, H) which generalize the convolution structure of M(G × H) and which make BM(G, H) into a K_G²-Banach ${}^1$-algebra, where K_G is Grothendieck's universal constant. Various topics relating to the ideal structure of BM(G, H) and the lifting of unitary representations of G × H to ${}^1$-representations of BM(G, H) are investigated.     

On Kato's inequality for the Weyl quantized relativistic Hamiltonian

In this note we give a simpler proof of Kato's inequality for the Weyl quantized relativistic HamiltonianH _A ^m of a spinless particle with a more singular vector potentialA(x) than in a previous paper of one of the authors. This article was processed by the author using the Springer-Verlag T_EX mamath macro package 1990