Incoherent quasielastic neutron scattering study on the polymorphism of tristearin: dynamical properties of hydrocarbon chains

Dynamical properties of acyl chains in the three polymorphic phases alpha, beta', and beta of tristearin [C(3)H(5)(OCOC(17)H(35))3] have been studied by means of incoherent quasielastic neutron scattering (IQNS) using selectively deuterated samples. The mean square displacement of hydrogen atoms, , was estimated from the scattering vector Q dependence of the elastic scattering component under the harmonic approximation. It was shown that the temperature dependence of was significantly different between the three phases. There was no marked difference in between these phases up to 193 K, and the value increased linearly with temperature. Although the beta phase remained linear up to 293 K, the alpha and beta' phases started to show a nonlinear increase around 200 K, suggesting an anharmonic nature of molecular motions. The alpha phase exhibited the most conspicuous temperature dependence. These characteristics were ascribable to the difference in the lateral packing of acyl chains. Compared with the beta phase which has a tightly packed T// subcell, the beta' and alpha phases have looser O perpendicular and H subcells, respectively. The molecular motion in the alpha phase was analyzed using the model of uniaxial rotational diffusion in a onefold cosine potential. It has been clarified that the rotational fluctuation about the chain axis in the alpha phase is rather restricted compared with that in the rotator phase of n-alkanes.     

Fano 3-folds with divisible anticanonical class

We show the nonvanishing of H ⁰(X,−K _X ) for any a Fano 3-fold X for which −K _X is a multiple of another Weil divisor in Cl(X). The main case we study is Fano 3-folds with Fano index 2: that is, 3-folds X with rank Pic(X)=1, -factorial terminal singularities and −K _X  = 2A for an ample Weil divisor A. We give a first classification of all possible Hilbert series of such polarised varieties (X,A) and deduce both the nonvanishing of H ⁰(X,−K _X ) and the sharp bound (−K _X )³≥ 8/165. We find the families that can be realised in codimension up to 4.     

An eigenvalue problem for derogatory matrices

A matrix A is called derogatory   if there is more than one Jordan submatrix associated with an eigenvalue λ$\lambda$. In this paper, we are concerned with the eigenvalue problem of this type of matrices.     

Dendrimer container for anion-responsive lanthanide complexation and "on-off" switchable near-infrared luminescence

A new dendrimer-type ligand dynamically switched the lanthanide complexation and luminescence profiles in response to external anions.     

The first synthesis of organosilyl-substituted aluminophosphate molecular sieves

Organosilyl groups were successfully incorporated in AFI and VFI aluminophosphate frameworks using organoalkoxysilanes to modify hydrophobicity and acidity of the molecular sieves.     

Enantioselective total synthesis of (+)-ottelione A, (-)-ottelione B, (+)-3-epi-ottelione A and preliminary evaluation of their antitumor activity

Enantioselective total synthesis of (+)-ottelione A (1) and (-)-ottelione B (2), novel and potent antitumor agents from a freshwater plant, and (+)-3-epi-ottelione A (3), the earlier proposed stereostructure of 1, was efficiently achieved starting from the known tricyclic compound 10. The synthesis involved the following key steps: i) coupling reactions of aldehydes 8 and 9 with the aromatic portion 7 (8+7-->15 and 9+7-->27), ii) base-induced hemiacetal-opening/epimerization reactions of the cyclic hemiacetals 6 and 27 (6-->17 and 27 a-->26 a), and iii) Corey-Winter's reductive olefination of the cyclic thiocarbonates 21 and 36 (21-->22 and 36-->37). The present total synthesis fully established the absolute configuration of these natural products. The cell growth inhibition profile, COMPARE analysis, and tubulin inhibitory assay of (+)-3-epi-ottelione A (3) and its O-acetyl derivative 24 demonstrated that these unnatural substances could be prominent lead compounds for the development of anticancer agents with a novel mode of action.     

Conformational control of [26]hexaphyrins(1.1.1.1.1.1) by meso-thienyl substituents

Conformational preference and chemical stability of meso-aryl-substituted [26]hexaphyrins(1.1.1.1.1.1) ([26]ArH) depend upon meso-aryl substituents. Although only a planar and rectangular conformation (type-II conformation) has been identified for [26]ArH so far, we have demonstrated here that a different conformation with all the pyrroles pointing inward (type-I conformation) is preferred for [26]ArH (7 and 11-I) bearing small 2-thienyl or 3-thienyl substituents at 15- and 30-positions. Both type-I and type-II [26]ArH exhibit diatropic ring currents, reflecting aromatic character. Type-I [26]ArH, such as 7 and 11-I, have been shown to serve as an effective ligand for Pd(II) ions to provide bis-Pd(II) complexes 12 and 13 with N(3)C(1) coordination through facile C--H bond activation.     

Intramolecular triarylmethane-triarylmethylium complexes with a naphthalene-1,8-diyl skeleton: isolation, structure, and reactivities of the C--H-bridged carbocations

Isolation and low‐temperature X‐ray analyses of intramolecular triarylmethane–triarylmethylium complexes with a naphthalene‐1,8‐diyl‐type skeleton have been achieved. These bridged cations prefer a C? H localized structure both in solution and in the solid state. The bridging hydrogen undergoes a facile intramolecular 1,5‐hydride shift from one carbon to another in solution. The C? H delocalized geometry is suggested to be the transition‐state structure of the degenerate rearrangement. Charge‐transfer interaction from the triarylmethane to the triarylmethylium units is evident in the electronic spectra. This interaction stabilizes the present cations. Low reactivity toward Brønsted acids indicates that these species are not the reaction intermediates in the acid‐assisted long‐bond cleavage of 1,1,2,2‐tetraarylacenaphthene derivatives.     

A chemiluminescence biochemical oxygen demand measuring method

A new chemiluminescence biochemical oxygen demand (BOD_CL) determining method was studied by employing redox reaction between quinone and Baker's yeast. The measurement was carried out by utilizing luminol chemiluminescence (CL) reaction catalyzed by ferricyanide with oxidized quinone of menadione, and Saccharomyces cerevisiae using a batch-type luminometer. In this study, dimethyl sulfoxide was used as a solvent for menadione. After optimization of the measuring conditions, the CL response to hydrogen peroxide in the incubation mixture had a linear response between 0.1 and 100 μM H₂O₂ (r² = 0.9999, 8 points, n = 3, average of relative standard deviation; R.S.D._av = 4.22%). Next, a practical relationship between the BOD_CL response and the glucose glutamic acid concentration was obtained over a range of 11-220 mg O₂ L⁻¹ (6 points, n = 3, R.S.D._av 3.71%) with a detection limit of 5.5 mg O₂ L⁻¹ when using a reaction mixture and incubating for only 5 min. Subsequently, the characterization of this method was studied. First, the BOD_CL responses to 16 pure organic substances were examined. Second, the influences of chloride ions, artificial seawater, and heavy metal ions on the BOD_CL response were investigated. Real sample measurements using river water were performed. Finally, BOD_CL responses were obtained for at least 8 days when the S. cerevisiae suspension was stored at 4 °C (response reduction, 69.9%; R.S.D. for 5 testing days, 18.7%). BOD_CL responses after 8 days and 24 days were decreased to 69.9% and 35.8%, respectively, from their original values (R.S.D. for 8 days involving 5 testing days, 18.7%).     

Molecular complex consisting of two typical external medicines: intermolecular interaction between indomethacin and lidocaine

The molecular complex formed between indomethacin (IDM) and lidocaine (LDC), which are typical external medicines, was studied. A thermal analysis, microscopic study and phase solubility technique suggested intermolecular interaction between IDM and LDC. The phase solubility profiles with IDM and LDC were classified as A(L)-type, indicating the formation of a 1 : 1 stoichiometric molecular complex. The apparent stability constant (K(S)), calculated from the slope and the intercept, was 4478.9 M(-1). A molecular ion peak was detected at 592.2 (m/z) from fast-atom bombardment-MS measurements, which was in accordance with the sum of the molecular weight for IDM (M(W): 357.81) and LDC (M(W): 234.38). The changes of IR spectra in the C=O stretching region showed that each intact hydrogen bond network was collapsed in the IDM-LDC system and strong interaction between IDM and LDC formed after their kneading. From the (1)H-NMR analyses, it was estimated that the dominant interactive site was the IDM carboxylic acid group which associated with the LDC diethyl amino group non-covalently.