Grassmann manifold of aJH-algebra

We study the set of rankp idempotents in a topologically simple Hilbert Jordan algebra (JH-algebra for short). To produce the differential geometric structure on, we establish Jordan algebraic results concerning the structure of some two-generator subalgebras. We identify geodesics, the Riemannian distance and the sectional curvature of by using the Jordan algebraic structure.     

Pulse radiolysis of 4,4'-bipyridyl aqueous solutions at elevated temperatures: spectral changes and reaction kinetics up to 400 degrees C

The spectral changes as well as the reaction kinetics of the transient species of 4,4'-bipyridyl (4,4'-bpy) have been experimentally investigated by pulse radiolysis techniques up to 400 degrees C. The results show that the transient species such as OH adduct 4,4'-bpyOH*, monoprotonated electron adduct 4,4'-bpyH*, and doubly protonated electron adduct 4,4'-bpyH2+* have 15-20 nm blue shifts from room temperature to 400 degrees C. For a deaerated neutral solution of 4,4'-bpy in the presence of tert-butyl alcohol, ethanol, or NaCOOH, the doubly protonated electron adduct is the main transient species at room temperature. But at temperatures > 350 degrees C, a monoprotonated form, the N-hydro radical 4,4'-bpyH*, becomes predominant. Interestingly, at room temperature, CO2-* could not efficiently react with 4,4'-bpy, but the reaction was accelerated with increasing temperature; at 350 degrees C, this reaction completed within 2 mus. Using an alkaline solution (pH = 11.5) of 4,4'-bpy in the presence of tert-butyl alcohol, we studied the N-hydro radical 4,4'-bpyH* from room temperature to 400 degrees C at 25 MPa. An estimation of the temperature-dependent G(e(aq)-) at 25 MPa agrees with our previous result with methyl viologen as a scavenger.     

Total synthesis of merrilactone A

Merrilactone A (1) has been shown to possess neurotrophic activity and thus is expected to hold therapeutic potential in the treatment of neurodegeneration diseases. In this paper, we report the total synthesis of (+/-)-1, employing, as key steps, a novel desymmetrization protocol of meso-diketone to construct the core cis-bicyclo[3.3.0]octyl system of 1 (3 --> 2) and a radical cyclization to install the highly congested C9-quaternary carbon (16 --> 17).     

Lactone and cyclic ether analogues of platelet-activating factor. Synthesis and biological activities

Six-membered lactone and tetrahydropyran analogues of platelet-activating factor (PAF), 4-11, and related antagonistic derivatives 41-46 were synthesized. None of the delta-lactones 4-7 showed PAF-like activities, while the corresponding cyclic ethers 8, 9 and 11 were slightly active. Some of the cyclic antagonists showed more potent inhibitory activities than the open chain antagonist CV-3988 against platelet aggregation (rabbit platelet-rich plasma, IC50) and hypotension (rat, ID50) induced by C16-PAF: e.g. dl-3-[6-[O-(trans-3-heptadecylcarbamoyloxytetrahydropyran-2- yl)methyl]phosphonoxy]hexylthiazolium (inner salt) (41d) (IC50 5.5 x 10(-7) M, ID50 0.046 mg/kg, i.v.); dl-3-[5-[O-(cis-3-heptadecylcarbamoylthiotetrahydropyran-2- yl)methyl]phosphonoxy]pentylthiazolium (inner salt) (43c) (IC50 5.7 x 10(-7) M, ID50 0.076 mg/kg, i.v.).     

Application of ion-exchange cartridge clean-up in food analysis IV. Confirmatory assay of benzylpenicillin, phenoxymethylpenicillin, oxacillin, cloxacillin, nafcillin and dicloxacillin, in bovine tissues by liquid chromatography-electrospray ionization tandem mass spectrometry

A multiresidue analytical method was developed for the confirmation of benzylpenicillin (PCG), phenoxymethylpenicillin (PCV), oxacillin (MPIPC), cloxacillin (MCIPC), nafcillin (NFPC) and dicloxacillin (MDIPC) in bovine tissues using electrospray ionization liquid chromatography-tandem mass spectrometry (LC-ESI-MS-MS) with a product ion scan mode. All penicillins gave [M-H]-, [M-H-CO2]- and [M-H-141]- as the product ion, when [M-H]- was selected as the precursor ion. Combination of an ion-exchange cartridge clean-up and the LC-ESI-MS-MS method can reliably identify all of these penicillins fortified at a concentration of 0.05 mg/kg in bovine tissues, including liver, kidney and muscle. The limits of confirmation satisfy the maximum residue limits for each of the penicillins established by the World Health Organization, US Food and Drug Administration, European Union and Japan.     

Measurement of the product ion ratio N4+/N3+ in the radiolysis of nitrogen

The ratio of N₄⁺ to N₃⁺ formed in the radiolysis of gaseous nitrogen has been measured to be 4.7 ± 0.4 using a time-resolved atmospheric pressure ionization mass spectrometer. The limit of error has been evaluated from the ion mass discrimination of the apparatus.     

Binding of sulfonamides to erythrocyte proteins and possible drug-drug interaction

The mode of binding of sulfonamides to erythrocyte proteins and possible drug-drug interaction between those compounds in erythrocytes resulting in changes in tissue levels were studied in rats using zonisamide (a novel antiepileptic agent possessing a sulfonamide group), several other sulfonamides and some antiepileptics without a sulfonamide group. In Michaelis-Menten plottings, the sulfonamide was found to be concentrated into erythrocytes in vitro and in vivo in a saturable high-affinity mode and in a linear low-affinity mode at ordinary therapeutic plasma levels through a simple diffusion process. Concentration in erythrocytes was affected by the presence of albumin in the extracellular medium. The cellular sulfonamide was readily replaced by extracellular sulfonamides in vitro. Even in vivo, erythrocyte levels of zonisamide were lowered by administration of other sulfonamides, although the plasma and tissue levels were not significantly changed since the plasma and tissue compartments of zonisamide were large relative to the erythrocyte compartment at ordinary therapeutic dose levels of zonisamide in animals and man. Therefore, disposition of zonisamide was not significantly influenced by other sulfonamides, but it is suggested that drug-drug interaction affecting the tissue levels may occur for a combination of sulfonamides with extremely different affinities for erythrocytes and low therapeutic plasma levels.     

Evaluation of chiral bidentate ligand–metal complexes in asymmetric 1,3-dipolar cycloaddition reaction of nitrones with 3-alkenoyl-2-oxazolidinones

For evaluation of a chiral C₂-symmetric bis(oxazoline) ligand, its Lewis acid complexes-catalyzed asymmetric 1,3-dipolar cycloaddition reactions of nitrones with electron-deficient dipolarophiles, 3-(2-alkenoyl)-1,3-oxazolidin-2-ones, have been investigated and it was found that the cycloadditions using a Cu(II)-bis(oxazoline) complex under optimized reaction conditions induced extremely high enantioselectivity.