Magnetite in the radular teeth of chitons

To understand the process by which living organisms synthesize magnetite, we measured the Mössbauer spectra on the teeth at different maturation stages along the radula of chitons. Our results show that magnetite is progressively mineralized from hydrous ferric oxide precursor in the early stage of maturation. As the denticles become fully mineralized, a part of magnetite is oxidized to maghemite and the excess of iron supply may be used for the formation of lepidocrocite.     

On the mechanism of the (3He,t) reaction

The (³He, t) reactions are investigated by means of the second-order perturbation method with the (³He-α-t) process and the ordinary DWBA term. The analyses are performed on the data of ⁴⁸Ca(³He, t)⁴⁸Sc(0⁰⁺, 2⁺, 4⁺, 6⁺), ⁹⁰Zr(³He, t)⁹⁰Nb(2⁺, 4⁺, 6⁺, 8⁺) and ^{46, 48, 50}Ti(³He, t)^{46, 48, 50}V(0⁺. The results show that the (⁺He-α-t) process is an important process in these reactions and a very good agreement between observed and calculated cross sections is obtained. The energy dependence of the cross section of the ⁹⁰Zr(³He, t)⁹⁰Nb(O⁺) reaction is also discussed.     

UV and IR absorption spectra of C3 embedded in solid para-hydrogen

This paper presents the UV and IR absorption spectroscopy of small carbon molecules of C₃ observed using a high-resolution Fourier-transform spectrometer. The C₃ molecules were produced by irradiation of dimers or larger clusters of acetylene with an ArF laser (λ=193 nm). Sharp UV absorption features with multiple structures were observed in the electronic transition of C₃. The sharp UV absorption demonstrates the potential of solid para-hydrogen as a matrix for high-resolution spectroscopy of UV–vis electronic transitions.     

Trajectory stabilization of a model car via fuzzy control

This paper deals with trajectory stabilization of a computer simulated model car via fuzzy control. Stability conditions of fuzzy systems are given in accordance with the definition of stability in the sense of Lyapunov. First, we approximate a computer simulated model car, whose dynamics is nonlinear, by T-S (Takagi and Sugeno) fuzzy model. Fuzzy control rules, which guarantee stability of the control system under a condition, are derived from the approximated fuzzy model. The simulation results show that the fuzzy control rules effectively realize trajectory stabilization of the model car along a given reference trajectory from all initial positions under a condition and the dynamics of the approximated fuzzy model agrees well with that of the model car.     

Preparation and characterization of copper(II) and nickel(II) complexes with novel tetraaza-macrocyclic schiff bases

Novel tetraaza-macrocycles with N-substituted carbamoyl groups were prepared by the reaction of 5,7,12,14-tetramethyl-1,4,8,11-tetraazacyclotetradeca-1,5,7,12-tetraene with isocyanates (RNCO, R = Ch₃ and C₆H₅). Their copper(II) and nickel(II) complexes were characterized by magnetic susceptibilities, electronic absorption spectra, and electrochemical properties. The complexing abilities and extractabilities of the ligands for the metal ions were investigated.     

Quadrature fringes wide-field optical coherence tomography and its applications to biological tissues

We propose and demonstrate quadrature fringes wide-field optical coherence tomography (QF WF OCT) to expand an optical Hilbert transformation to two-dimensions. This OCT simultaneously measures two quadrature interference images using a single InGaAs CCD camera to obtain en face OCT images. The axial and lateral resolutions are measured at 29 μm in air and 70 μm limited by a pixel size of camera using a superluminescent diode with a wavelength of 1.3 μm as the light source; the system sensitivity is determined to be −90 dB. The area of the en face OCT images is 4.0 mm × 4.0 mm (160 × 160  pixels). The OCT images are measured axially with steps of 10 μm. The en face OCT images of a in vivo human fingertip and a in situ rat brain are three-dimensionally measured up to the depth of about 3 mm with some degradations of a lateral resolution.     

Curcumin Conjugates of Non-steroidal Anti-Inflammatory Drugs: Synthesis,Structures, Anti-proliferative Assays,Computational Docking,and Inflammatory Response

In an effort to combine the anti-proliferative effect of CUR-BF₂ and CUR compounds with anti-inflammatory benefits of non-steroidal anti-inflammatory drugs (NSAIDs), a library of the bis- and mono-NSAID/CUR-BF₂ and NSAID/CUR conjugates were synthesized by coupling flufenamic acid, flurbiprofen, naproxen, indomethacin, and ibuprofen to diversely substituted hydroxy-benzaldehydes via an ester linkage, and by subsequent reaction with acetylacetone-BF₂ to form the bis- and the mono-NSAID/CUR-BF₂ adducts. Since conversion to NSAID/CUR by the previously developed decomplexation protocol showed limited success, a set of NSAID/CUR conjugates were independently prepared by directly coupling the NSAIDs with parent curcumin. The bis-NSAID/CUR-BF₂ and bis-NSAID-CUR hybrids exhibited low cytotoxicity in NCI-60 assay, and in independent cell viability assay on colorectal cancer (CRC) cells (HCT116, HT29, DLD-1, RKO, SW837, CaCo2) and in normal CR cells (CCD841CoN). By contrast, the mono-naproxin and mono-flurbiprofen CUR-BF₂ adducts exhibited remarkable anti-proliferative and apoptopic activity in NCI-60 assay most notably against HCT-116 (colon), OVCAR-3 (ovarian), and ACHN (renal) cells. Computational molecular docking calculations showed favorable binding energies to HER2, VEGFR2, BRAF, and Bcl-2 as well as to COX-1 and COX-2, which in several cases exceeded known inhibitors. The main interactions between the ligands and the proteins were hydrophobic, although several hydrogen bonds were also observed. A sub-set of six compounds that had exhibited little or no cytotoxicity were tested for their anti-inflammatory response with THP-1 human macrophages in comparison to parent NSAIDs or parent curcumin.     

Notable effect of an electron-withdrawing group at C3 on the selective formation of alkylidenecyclobutanes in the thermal denitrogenation of 4-spirocyclopropane-1-pyrazolines. Nonstatistical dynamics effects in the denitrogenation reactions

A detailed study of the thermal denitrogenation of 3-carbomethoxy-substituted 4-spirocyclopropane-1-pyrazolines 6 was conducted. Alkylidenecyclobutane derivatives 7 were selectively formed in a stereospecific manner. Unrestricted density functional calculations for a 1-pyrazoline 10a indicated that the concerted cleavage of two C-N bonds is the energetically favored process for the denitrogenation reaction to give the 2-spirocyclopropyl 1,3-diyl, followed by a conrotatory ring-closure process, which was calculated to be the energy minimum pathway, to afford a spiropentane derivative. The calculated energy minimum pathway is largely inconsistent with the experimental results observed for the denitrogenation of 6 and 10a. The contradiction between the experimental and standard computational results was solved by considering nonstatistical dynamics effects in the concerted denitrogenation reactions. Although the energy minimum pathway from the transition states of the concerted denitrogenation of the 3-carboalkoxy-substituted 1-pyrazolines involves generation of the corresponding 1,3-diradicals, many trajectory calculations using the Bohn-Oppenheimer molecular dynamics model from the transition state for the concerted denitrogenation led directly to the formation of alkylidenecyclobutanes at the UB3LYP/6-31G(d) level of theory.