Crystal-face dependences of surface band edges and hole reactivity, revealed by preparation of essentially atomically smooth and stable (110) and (100) n-TiO(2) (rutile) surfaces

Essentially atomically smooth (100) and (110) n-TiO(2) (rutile) surfaces were prepared by immersion of commercially available single-crystal wafers in 20% HF, followed by annealing at 600 degrees C in air. The obtained surfaces were stable in aqueous solutions of pH 1-13, showing no change in the surface morphology on an atomic level, contrary to atomically flat surfaces prepared by ion sputtering and annealing under UHV. The success in preparation of the atomically smooth and stable n-TiO(2) surfaces enabled us to reveal clear crystal-face dependences of the surface band edges and hole reactivity in aqueous solutions.     

Mechanism of the growth of ZnSe nanowires with Fe catalysts

ZnSe nanowires of high optical quality have been grown with Fe catalysts at the usual temperatures for the fabrication of ZnSe-base optoelectronic devices (about 600 K). It is found that only Fe nanoparticles of 10-50 nm diameter act as catalysts in the narrow temperature range around 600 K (with a minimum temperature of 473-523 K, and a maximum temperature of 623-673 K). The growth mechanism is discussed in terms of the vapour-liquid-solid mechanism.     

Magneto-elastic properties of Tb<Subscript>3</Subscript>Ga<Subscript>5</Subscript>O<Subscript>12</Subscript> (TGG)

The temperature dependence of the elastic constants in Tb₃Ga₅O₁₂ was measured and analysed with a simple crystal field model. The magneto-elastic coupling constants have been deduced from this experiment. The coupling constant g_Γ5, related to the c₄₄ mode, is anomalously large. These coupling constants are important for the interpretation of the phonon Hall effect.     

Analyticity of ground states of the XY-model

Ground states of the XY-model obtained earlier are shown to depend analytically on parameters (, ) of the model except at critical lines.     

Stability of recombinant human epidermal growth factor in various solutions

The stability of recombinant human epidermal growth factor (hEGF) in various solutions was examined. hEGF degraded spontaneously and temperature-dependently to several degradation products in phosphate buffered saline or in 0.1 N acetic acid. The enzymatic degradation was observed in human serum or in pepsin/HCl solution. The structure and biological activities of these compounds were examined. The results suggest that the Asp11 and Trp50 residues are important for the receptor binding.     

Allylation of epoxides with allylic indium reagents

Allylindium sesquihalide reacts with epoxide to give homoallyl alcohol via a 1,2-shift reaction. In contrast, allylindate gives the ring-opening product without rearrangement.     

Indecomposable representations with invariant inner product

Consequences of the existence of an invariant (necessarily indefinite) non-degenerate inner product for an indecomposable representation π of a groupG on a space \(\mathfrak{H}\) are studied. If π has an irreducible subrepresentation π₁ on a subspace \(\mathfrak{H}_1 \) , it is shown that there exists an invariant subspace \(\mathfrak{H}_2 \) of \(\mathfrak{H}\) containing \(\mathfrak{H}_1 \) and satisfying the following conditions: (1) the representation π ₁ ^# =π mod \(\mathfrak{H}_2 \) on \(\mathfrak{H}\) mod \(\mathfrak{H}_2 \) is conjugate to the representation (π₁, \(\mathfrak{H}_1 \) ), (2) \(\mathfrak{H}_1 \) is a null space for the inner product, and (3) the induced inner product on \(\mathfrak{H}_2 \) mod \(\mathfrak{H}_1 \) is non-degenerate and invariant for the representation $$\pi _2 = (\pi _2 |_{\mathfrak{H}_2 } )\bmod \mathfrak{H}_1 ,$$ a special example being the Gupta-Bleuler triplet for the one-particle space of the free classical electromagnetic field with \(\mathfrak{H}_1 \) =space of longitudinal photons and \(\mathfrak{H}_2 \) =the space defined by the subsidiary condition.     

Synthesis of (+/-)-trans- or cis-(5-aminomethyltetrahydrofuranyl)imidazole by Mitsunobu cyclization: synthetic studies toward novel histamine H3 or H4-ligands

The (+/-)-trans- or cis-4(5)-(5-aminomethyltetrahydrofuranyl)imidazole [1 and 2] were synthesized by the Mitsunobu cyclization, starting from L-glutamic acid.     

FORMATION OF NON-VIABLE SPORES OF DICTYOSTELIUM DISCOIDEUM BY UV-IRRADIATION AND CAFFEINE

Abstract We have characterized the spores formed from amoeboid cells of the wild type strain of Dictyostelium discoideum after UV-irradiation. Cell differentiation in the presence of caffeine after a fluence of 300 J/m² resulted in a population of spores which was 98% non-viable. The UV-irradiation did not affect the conversion of the spores to swollen spores but did affect the conversion of swollen spores to amoeboid cells. When the germination of the spores was done without caffeine, we detected only a small effect on conversion of swollen spores to amoeboid cells and on the beginning of growth. On the other hand, in the presence of caffeine, the spores had a remarkable delay in both. It was also shown that few, if any, pyrimidine dimers exist in the DNA of the non-viable spores. Possible mechanisms of formation of non-viable spores are discussed.