RPA response function for quasielastic electron scattering in the relativistic σ-ω model

In the Hartree approximation for the relativistic σ-ω model, the σ-meson dominates the longitudinal response function for quasielastic electron scattering, through the effective mass of the nucleon. In the random phase approximation, however, the effective mass effect is cancelled by the particle-hole correlation due to the σ-meson exchange, and the ω-meson also plays an important role in the response function.     

Adenopeptin, a new apoptosis inducer in transformed cells from Chrysosporium sp.

A new antitumor antibiotic, adenopeptin (1), was isolated from the culture broth of Chrysosporium sp. PF1201. The planar structure, which includes a tridecapeptide and a hexahydropyrrolo[1,2-a]pyrimidinium, was elucidated by mass spectrometric and NMR experiments. Adenopeptin (1) induced apoptotic cell death in cells transformed with the adenovirus oncogenes.     

Development of Oxidation Sources in Preparation of High-Tc Oxide Superconductor Thin Films Using the Molecular Beam Epitaxy Method

Film preparation of oxide superconductors, mainly of the 1-2-3 (RBa₂Cu₃O_x) and Bi-containing (Bi-Sr-Ca-Cu-O) systems, by evaporation of either metals or metal compounds by low pressure is summarized, with a particular focus on the development of oxidation sources essential to the technique. Oxidizing reagents that enable the oxidation of metal evaporates to take place in high (0·1 to 10_?3 Pa) or even ultra-high (<10_?5 Pa) vacuum are summarized using the experiments of those who tried to apply the molecular beam epitaxy method to atomically controlled fabrication of thin films of the material, especially for device processing. The evaporation in various kinds of oxidizing atmosphere, including the simple method of in situ annealing of the metal layers in oxygen to the more advanced in situ preparation of the films with strong oxidizing reagents such as atomic oxygen, ozone, nitric oxide, etc. along with the thermochemistry of the oxidation of metals by low pressure with these reagents is reviewed.     

Three dimensional gain analysis of free electron laser with focusing permanent magnet wiggler

A three dimensional simulation software system developed to estimate a free electron laser (FEL) gain has been applied to FEL using a standard plane polarized wiggler and an alternately shifted magnet wiggler. It is seen for the latter wiggler that a large filling factor could be selected and each maximum gain corresponding to each orbit of electron beam concentrates at a certain frequency region of FEL radiation. It is, therefore, implied that a proper shift between the adjacent magnets in the wiggler produces the improvement of the FEL gain.     

An electron microscopic study of the archaeal feast/famine regulatory protein 5. Fourier filtration of images

Microcrystals of the feast/famine regulatory protein (FFRP) pot0434017 (FL11) were prepared by sonicating larger crystals. Using the microcrystals a cryo-electron micrograph was obtained, which showed a hexagonal packing of cylinder-like assemblies of FL11. This micrograph was processed by selecting, in the Fourier space, spots reflecting the crystal lattice, thereby removing the noise. The microcrystal was not totally free from distortion, and cylinders in local clusters adopted slightly different orientations. Thus, 25 hexagonal units closest to the ideal, each containing a cylinder at the center surrounded by six others, were manually selected. The averaged image was further processed to yield a perfect six-fold symmetry. These processed images, and some of the original images too, show bridges connecting cylinders, each corresponding to two pairs of N-domains, protruding from the two cylinders and contacting between them in the X-ray structure.     

Flow injection analysis for traces of zinc with immobilized carbonic anhydrase

A small column packed with immobilized bovine carbonic anhydrase is used for determination of traces of zinc in aqueous solution, based on the measurement of recovered esterase activity of the metal-free apoenzyme after taking up zinc from the sample solution. Conditions for the removal of zinc from the immobilized enzyme and for activity measurement are established. A linear calibration graph is obtained between 1 × 10^?8 and 4 × 10^?7 g of zinc. Then the method is successfully applied to the determination of zinc in tea, sediment and spring water.     

Radical cyclopolymerizations of diallylsilanes and triallylsilanes

The radical polymerizations of diallylsilanes such as diallyldimethylsilane ( 1 ) and diallylmethylphenylsilane ( 2 ) have been conducted. Both poly(diallyldimethylsilane) ( 3 ) and poly(diallylmethylphenylsilane) ( 4 ) are soluble in benzene, methyl ethyl keton (MEK), and chloroform, slightly soluble in acetone, and insoluble in methanol and ethanol. No insoluble fraction of either polymer was obtained. Very little evidence of vinyl protons in the ¹H-NMR spectra can indicate that both polymerizations predominantly proceed with intramolecular cyclization. In order to study the ring size of cyclic structure in the repeating unit of the polymers, a model compound, allyl(2-chloropropyl)dimethylsilane ( 5 ), was synthesized and cyclized with Bu₃SnH in the presence of azobisisobutyronitrile (AIBN) in benzene, under similar condition of those for the cyclopolymerizations. The product was analyzed with GC–MS which showed that the five-membered ring compound, 1,1,3,4-tetramethylsilacyclopentane, was not formed. From the result of the cyclization of the model compound, it can be suggested that the polymerizations undergo with only h–t intramolecular cyclization to form a six-membered ring in the repeated unit. The ¹³C-NMR spectra of 3 and 4 were measured to study the ring size and the configuration of the cyclic structures. The two peaks at ?1.6 and ?3.4 ppm of the spectrum of 3 show that there are two kinds of methyl carbons in the repeating unit. From consideration of the model reaction and the number of the peaks of the NMR spectrum, it can be considered that the polymer main chain is assembled with the six-membered ring in cis-form, and the two signals are assigned to equatorial and axial methyl carbons, respectively. The two peaks at -1.5 and -5.1 ppm of the ¹³C-NMR spectrum of 4 can be assigned similarly. The radical cyclopolymerizations of triallylsilanes such as methyltriallylsilane ( 6 ) and phenyltriallylsilane ( 7 ) were conducted. The ¹H-NMR spectra of poly(methyltriallylsilane) ( 8 ) and poly(phenyltriallylsilane) ( 9 ) show broad peak around 5 ppm for vinyl protons and around 2 ppm for alkyl protons. Comparisons of the relative intensities of the peaks indicate that both polymerizations undergo with single ring closure to form a polymer with monocyclic structure moiety, cyclosilahexane, and an allyl group in a repeating unit of 8 and 9 .