One-pot beta-substitution of enones with alkyl groups to beta-alkyl enones

Vinylic hydrogens at the beta-position of enones were effectively substituted with alkyl groups in a one-pot procedure to afford beta-alkyl enones in good to high isolated yields by conjugate addition of higher-order dialkyl cyanocuprates to enones, followed by a reaction with N-tert-butylbenzenesulfinimidoyl chloride at -78 degree C.     

Screening and diagnosis of beta-ureidopropionase deficiency by gas chromatographic/mass spectrometric analysis of urine

Dihydropyrimidine dehydrogenase (DHPDase), dihydropyrimidinase (DHPase) and beta-ureidopropionase (betaUPase) are the enzymes that catalyze the first, second, and third steps of the degradation of pyrimidines, respectively. beta-Ureidopropionate (betaUP) and beta-ureidoisobutyrate (betaUIB) are increased in the urine of patients with betaUPase deficiency. The original case in which betaUPase deficiency was discovered by NMR spectroscopy was an 11-month-old patient who presented with hypotonia and dystonic movement. We detected a second but asymptomatic case during a pilot study of neonatal screening with filter-paper urine, urease pretreatment and gas chromatography/mass spectrometry (GC/MS). The urease pretreatment of urine without fractionation resulted in a high recovery of these polar ureide compounds and allowed the highly sensitive GC/MS detection and diagnosis of betaUPase deficiency. betaUP and betaUIB were identified using GC/MS techniques. In the urine of the neonate with betaUPase deficiency, betaUP and betaUIB were persistently increased. Thymine, 5,6-dihydrothymine and 5,6-dihydrouracil were increased only moderately but significantly. It is known that thymine and uracil increase markedly in DHPDase deficiency, and 5,6-dihydrothymine and 5,6-dihydrouracil increase in DHPase deficiency. Therefore, betaUPase deficiency can be differentially diagnosed from the first and second enzyme deficiencies. Application of this specific and sensitive diagnostic procedure will lead to an understanding of the clinical heterogeneity of betaUPase deficiency. Furthermore, the identification of patients with defects in pyrimidine metabolism will enable doctors to avoid cancer chemotherapy with pyrimidine analogues such as 5-fluorouracil, which could be dangerous for these patients.     

Binuclear iron(II) complex from a linked-bis(amidinate) ligand: synthesis and its reaction with carbon monoxide

Binuclear iron(II) complexes supported by a cyclohexane-linked bis(amidinate) ligand have been isolated and structurally characterized.     

High-intensity Si cluster ion emission from a silicon target bombarded with large Ar cluster ions

Secondary ions emitted from Si targets were measured with a quadrupole mass spectrometer under large Ar cluster and monomer ion bombardment. Incident ion beams with energies from 7.5 to 25 keV were used and the mean size of the Ar cluster ion was about 1000 atoms/cluster. Si_n⁺ ions with n values up to n = 8 were detected under Ar cluster ion bombardment, whereas Si cluster ions were scarcely detected under Ar monomer ion bombardment. These cluster ion yields showed the power law dependence on the cluster size.     

Preferential uniplanar orientation mechanism of the (101) crystal plane of regenerated cellulose

The molecular orientation behavior of regenerated cellulose, in both crystalline and noncrystalline phases, was investigated quantitatively under various conditions during coagulation-regeneration from viscose solution and during drying of the resulting gel film. It was concluded that the stronger the tensions which arise parallel to the film surface during coagulation-regeneration and drying of the gel film, the more prominent become the uniplanar orientation of the (101) crystal plane and planar orientations of the crystal b axis and noncrystalline chain segments, all parallel to the film surface and associated with considerable distortion and disintegration of the regenerated crystal. This conclusion suggests an orientation mechanism of the cellulose II crystal, namely, rotation of the crystal around the U_{(101 )} axis associated with slippage of the (101) crystal plane, the most highly hydrated and most readily dislocated plane, in the direction of the tension, which is also parallel to the surface of the film. The behavior of this type of uniplanar orientation of the (101) crystal plane is characterized semiquantitatively by comparing observed distributions of the orientation of crystallographic axes with those calculated on the basis of a relatively simple model for crystal orientation.     

Polymer foil applicable to the tilted foil technique

A polymer foil of polyethylene-terephthalate was successfully used for the tilted foil to create nuclear polarization of beta-emitters. The foil was carefully prepared to produce atomic flatness on the surfaces. The resultant smoothness was confirmed with beta-NMR measurements on¹²B and found to be as good as those of carbon foils used previously in the measurements.     

Synthesis of peptides related to immunoglobulin E (IgE) and the examination of their pharmacological activity

Five kinds of oligopeptides H-Asp-Ser-Asp-OH (1), H-Asp-Gly-Lys-OH (2), H-Ser-Asp-Gly-Lys-OH (3), H-Asp-Ser-Asp-Gly-Lys-OH (4), and H-Ala-Asp-Ser-Asp-Gly-Lys-OH (5) related to immunoglobulin E (IgE) were synthesized by the conventional solution method with the objective of obtaining a new type of antiallergic agent. Their pharmacological activity was examined by measuring the inhibition of the production of IgE and relaxation of the smooth muscle contraction of rabbit aorta. H-Ala-Asp-Ser-Asp-Gly-Lys-OH (5) displayed potent inhibition against the production of IgE antibody (69.6%) and relaxation against the contraction of rabbit aorta.     

An echolocation model for range discrimination of multiple closely spaced objects: transformation of spectrogram into the reflected intensity distribution

Using frequency-modulated echolocation, bats can discriminate the range of objects with an accuracy of less than a millimeter. However, bats' echolocation mechanism is not well understood. The delay separation of three or more closely spaced objects can be determined through analysis of the echo spectrum. However, delay times cannot be properly correlated with objects using only the echo spectrum because the sequence of delay separations cannot be determined without information on temporal changes in the interference pattern of the echoes. To illustrate this, Gaussian chirplets with a carrier frequency compatible with bat emission sweep rates were used. The delay time for object 1, T1, can be estimated from the echo spectrum around the onset time. The delay time for object 2 is obtained by adding T1 to the delay separation between objects 1 and 2 (extracted from the first appearance of interference effects). Further objects can be located in sequence by this same procedure. This model can determine delay times for three or more closely spaced objects with an accuracy of about 1 micros, when all the objects are located within 30 micros of delay separation. This model is applicable for the range discrimination of objects having different reflected intensities and in a noisy environment (0-dB signal-to-noise ratio) while the cross-correlation method is hard to apply to these problems.