Novel isomerization of dibenzocyclooctadiene lignan lactone —first synthesis of (±)-stegane—

(±)-Isostegane isomerized into (+-)-isopicrostegane, (±)-picrostegane, and (±)-stegane, the parent compound o steganacin-type dibenzocyclooctadiene lignan lactones.     

Dendritic effects on the ordered assembly and the interfacial one-electron oxidation of redox-active dendron-functionalized gold nanoparticles

A higher generation dendron with a long-alkyl chain thiol (DA2-SH) induced the formation of nanoparticles with a small core with quite a narrow size distribution (1.5 +/- 0.1 nm), the self-assembly of one-dimensional arrays of these gold nanoparticles (DA2-Au), and the stabilization for the formation of the radical cation of the phenothiazine of DA2-Au nanoparticles from the interfacial one-electron oxidation of the nanoparticles with NOBF4.     

Adaptive echolocation sounds of insectivorous bats, Pipistrellus abramus, during foraging flights in the field

Echolocation pulses emitted by wild Pipistrellus abramus were investigated while foraging for insects in the field. Similar to other European pipistrelles, the frequency structure during foraging varied. During the search phase, the bats emitted long shallow frequency-modulated pulses 9-11 ms in duration, whereas the maximum pulse duration of the bats approaching a large target wall in the laboratory was 3 ms. No significant difference was observed between decreases in the interpulse interval during these two approach flights. It is concluded that the bats use a long quasi-constant frequency pulse to find a weak echo from a small prey target.     

Ring-Opened Hemiporphyrazines: Helical Molecules Exhibiting Circularly Polarized Luminescence

We designed and synthesized a new type of small helical molecule exhibiting intense circularly polarized luminescence (CPL) ( 1_2H ) by modifying a 20π-electron hemiporphyrazine with a large transition magnetic dipole moment. The hemiporphyrazine ring was opened and one additional pyridine unit was introduced, resulting in an overlap of two pyridine rings. X-ray structure analysis confirmed that 1_2H and its zinc complex ( 1_Zn ) adopt a helical geometry. A racemic mixture of 1_Zn was resolved into two enantiomers ((P)- and (M)- 1_Zn ), which exhibited CPL with a high luminescence dissymmetry factor (g_lum) value of ±2.1×10⁻². The origin of the large g_lum value was rationalized by means of DFT calculations. Helical structures could be formed in a diastereoselective manner by covalently attaching chiral units to the skeleton ( 1’_2H and 1’_Zn ). 1_Zn was found to possess chiral recognition ability for amines.     

Crystal structure of the new FeSe(1-x) superconductor

The newly discovered superconductor FeSe(1-x) (x approximately 0.08, T(c)(onset) approximately 13.5 K at ambient pressure rising to 27 K at 1.48 GPa) exhibits a structural phase transition from tetragonal to orthorhombic below 70 K at ambient pressure-the crystal structure in the superconducting state shows remarkable similarities to that of the REFeAsO(1-x)F(x) (RE = rare earth) superconductors.     

On the Upper Bound of Some Geometric Constants of Absolute Normalized Norms on $${\mathbb{R}^2}$$

This is a continuation of the paper (Mizuguchi and Saito, Ann Funct Anal 2:22–33, 2011). We consider the Banach space \({X=(\mathbb{R}^2, \|\cdot\|)}\) with a normalized, absolute norm. We treat three geometric constants; the von Neumann–Jordan constant C _NJ(X), the modified von Neumann–Jordan constant \({C^{\prime}_{\rm NJ}(X)}\) and the Zb?ganu constant C _Z (X). We consider the conditions in which these constants coincide with their upper bound.