Infrared lattice bands of some pearls

From analysis of anisotropical lattice bands properties of 50 reflection spectra both of the CO stretching and bending bands measured from some pearl (Ca⁺⁺CO ₃ ^–– or Ca⁺⁺HCO ₃ ^–– layer) we discussed following subjects.i) Quantized properties present both in reflectivity and in energy. ii) classifications of the Optical Activity. iii) Polar distributions of the CO₃ oscillators in Ca⁺⁺CO ₃ ^–– surface mono-layer. iv) Force constants of these oscillators. v) Step variation of the dipolemoment and their influences to the degree of Optical Activity. vi) Two types of hysteresis loops of the values of Y_N (M_2Jbend ()/M_1Jstret. ()) derived from the oscillators which are at innert-state, at weak active-state and at active-state.     

IR Spectra and Structure of Immunoactive 8–Azasteroids in Model Compounds

The IR spectra of biologically active molecules of 8-azasteroids and model compounds in the region of C=O, C=C, C--N, and C--H vibrations (1800–1400 cm^–1) have been studied in detail. The structure of compounds containing isostructural and isoelectronic --acyl----aminovinylcarbonyl and --acyl----alkoxyvinylcarbonyl fragments have been analyzed. Interpretation of the structure of the IR spectra and of the specificity of the manifestation of the vibrational modes under consideration in the molecules of a particular class of 8-azasteroids is given. The electronic structure of the molecules under investigation complies with the model of mesomeric tautomerism of the aminovinyldicarbonyl fragment.     

Levels in <Superscript>127</Superscript>La fed by the <Superscript>127</Superscript>Ce beta-decay

The low-lying levels in ¹²⁷La have been studied through the -decay of ¹²⁷Ce ( T_1/2 = 29s) produced by bombarding a ^natMo target with a 185-MeV ³⁵Cl beam. Reaction products were on-line mass-separated, and -ray singles and - coincidence measurements were performed. Conversion electrons were also measured and multipolarities of transitions have been derived. The half-life of the 210.9-keV level was determined to be (1.9±0.3)ns by the - delayed coincidence technique. The level scheme obtained has been compared with calculations based on the Nilsson model.     

Supertubes versus superconducting tubes

In this paper we show the relationship between cylindrical D2-branes and cylindrical superconducting membranes described by a generic effective action at the bosonic level. In the first case the extended objects considered, arose as blown up type IIA superstrings to D2-branes, named supertubes. In the second one, the cosmological objects arose from some sort of field theories. The Dirac–Born–Infeld action describing supertubes is shown to be equivalent to the generic effective action describing superconducting membranes via a special transformation. (Dedicated to Prof. Alberto García on the occasion of his 60th birthday)     

Synthesis of peptidomimetics using a polymer-bound Boc-linker

Boc-resin-bound -hydroxy--amino-aldehydes are accessible starting from N-terminally bound amino acidesters by using Dondoni's C₁-homologationreaction sequence. The conversion of these synthons totwo different peptide mimetics – 2-hydroxy-1,3-ethyl-diamines and -hydroxy--amino-vinyl sulfones – hasbeen investigated. The successful transfer of thecomplex -amino acid homologation reactionsequence into solid-phase chemistry demonstrates thepotentials of the Boc-resin for synthesis of peptidomimetics.     

Role of the Carbohydrate Moiety and of α-L-Fucose in the Stabilization and the Dynamics of the Lens culinaris Agglutinin–Glycoprotein Complex. A Fluorescence Study

Interaction between the fluorescent Lens culinaris agglutinin–fluorescein complex (LCA-FITC) and two glycoproteins, lactotransferrin (LTF) and serotransferrin (STF), was studied. The two glycoproteins have the same glycan structures, with one difference: the lactotransferrin glycans contain a fucose residue -1,6-linked to the N-acetylglucosamine residue involved in the N-glycosylamine linkage. Fluorescence intensity quenching of the LCA-FITC complex shows that affinity between LCA and lactotransferrin is 50 times higher than that between LCA and serotransferrin, the fucose playing a major role in this high affinity (K _a is equal to 9.66 and 0.188 M ^–1 for the LCA–LTF complex and LCA–STF complex, respectively). Time-resolved anisotropy decay indicates that the rotational correlation time of LCA (20 ns) does not change to a large extent whether the glycoproteins are bound to LCA or not. This suggests that there is no extended physical contact between LCA and the glycoproteins. The interaction between LCA and the glycoproteins occurs likely only via the carbohydrate chains, the STF and the LTF rotating almost-freely in the vicinity of LCA, with the glycans as an anchor.     

Multivector Dirac Equation and ℤ 2-Gradings of Clifford Algebras

We generalize certain aspects of Hestenes's approach to Dirac theory to obtain multivector Dirac equations associated to a large class of representations of the gamma matrices. This is done by replacing the usual even/odd decomposition of the space-time algebra with more general ₂-gradings. Some examples are given and the chiral case, which is not addressed by the usual approach, is considered in detail. A Lagrangian formulation is briefly discussed. A relationship between this work and certain quaternionic models of the (usual) quantum mechanics is obtained. Finally, we discuss under what conditions the Hestenes's form can be recovered and we suggest a geometrical interpretation for the corresponding situation.     

Photoelectrochemical Characteristics Of α-Fe2O3 Nanocrystalline Semiconductor Thin Film

-Fe₂O₃ single crystal thin films have been prepared from 45nm diameter colloid. These thin nanocrystalline films exhibit a typical behavior of n-type semiconductor material because of the anodic photocurrent generation. The anodic photocurrent response upon illumination and the reversal spike of cathodic current upon the light switched off suggests that the electrons can flow in both directions and no space charge layer exists at the thin film/electrolyte interface. The decreased photocurrent responses of thicker films can be explained by the electric resistance effect and recombination effect. Moreover, the thicker film will lead to a poor photocurrent response for short wavelength light. Considering the use of sunlight, the thin film thickness should be controlled to an optimal value.     

Upper limits for lepton-flavor violation from the exotic μ− ν e− conversion

The transition matrix elements for coherent and incoherent channels of the neutrinoless ^– e^– conversion are investigated. The results refer to the ²⁷Al nucleus which has recently been chosen as a target in the MECO experiment at Brookhaven aiming to search for -e conversion events with a sensitivity 10^-17. These results are compared to those obtained previously for ⁴⁸Ti and ²⁰⁸Pb targets. We focus on the contributions to the branching ratio e^– originating from scalar, vector and axial vector interactions resulting in conventional extentions of the standard model and minimal supersymmetric models with and without -parity violation. With our calculations we extract very severe constraints for the flavor violation parameters.