Electrochemical behavior of dopamine and ascorbic acid at osmium(II) complex cationic monolayer modified gold electrodes.

The electrooxidation of dopamine (DA) and ascorbic acid (AA) was studied using gold electrodes modified by a cationic self-assembled monolayer of [Os(bpy)2(bpy-(CH2),3SH)]2+ by cyclic voltammetry. At an [Os(bpy)2(bpy-(CH2)13SH)]2+/Au electrode, the oxidation peak of DA shifted to a much more positive potential as compared with that of a bare gold electrode, while the oxidation peak potential of AA showed a slightly negative shift due to their different electrostatic interactions with the cationic monolayer. Thus, a sufficient potential difference was achieved for distinguishing the electrochemical responses of DA and AA. However, when CH3(CH2)11SH was mixed into the cationic monolayer, the enhanced packing of the mixed monolayer blocked the access of DA or AA to the electrode, resulting in further positive shifts for both oxidation-peak potentials.     

Two-dimensional assembly of [Mn(III)₂Mn(II)₂] single-molecule magnets and [Cu(pic)₂] linking units (Hpic = picolinic acid)

In an attempt to develop novel coordination networks of SMMs, a Cu(II) picolinate complex has been used to coordinate S(T) = 9 tetranuclear Mn-based SMMs resulting in an intriguing 2D framework exhibiting a magnet-like behavior at low temperature.     

Mechanical characteristics and morphological effect of complex crossed structure in biomaterials: fracture mechanics and microstructure of chalky layer in oyster shell

The complex crossed structures with a polymorph of calcite, termed a chalky layer, which make up much of the shell of an oyster, are composed of flames and leaflets. Two layers, folia and the chalky layer in the giant Pacific oyster (Crassostrea gigas) were examined using SEM (scanning electron microscope), micro-area-XRD (X-ray diffraction) and FT-IR (Fourier transform infrared spectrometer) to determine their morphologies and component characteristics. The chalky layer was also tested using microindentation to assess its mechanical properties, and a microcrack was generated to study the fracture mechanism of the chalky layer. From an analysis of the secondary protein structure, it was shown that the ordered structures of the two layers, α-helix and β-structure, are similar but that the unordered structures are different. Moreover, the foliated rods at the interface of the chalky layer play a key role in the crystal growth of the chalky layers. Comparing the morphology and the preferred orientation of foliated laths, the advantages of the relatively high density and low hardness of the chalky layer have interesting implications regarding the development of sophisticated complex composites.     

Fractional statistics in the fractional quantum Hall effect

A microscopic confirmation of the fractional statistics of the quasiparticles in the fractional quantum Hall effect has so far been lacking. We calculate the statistics of the composite-fermion quasiparticles at nu=1/3 and nu=2/5 by evaluating the Berry phase for a closed loop encircling another composite-fermion quasiparticle. A careful consideration of subtle perturbations in the trajectory due to the presence of an additional quasiparticle is crucial for obtaining the correct value of the statistics. The conditions for the applicability of the fractional statistics concept are discussed.     

A multiscale cell boundary element method for elliptic problems

In this paper we introduce the multiscale cell boundary element method (MsCBE method). The method is obtained by applying the oversampling technique of the MsFEM by Hou and Wu [T.Y. Hou, X.H. Wu, A multiscale finite element method for elliptic problems in composite materials and porous media, J. Comput. Phys. 134 (1997) 169–189] to the newly developed numerical method, the cell boundary element(CBE) method by the author and his colleagues. The advantage of the MsCBE method is that it preserves flux exactly on arbitrary subdomain without needing the dual mesh. A complete H¹ convergence analysis and numerical examples confirming our analysis are presented.     

Dual-path handheld system for cornea and retina imaging using optical coherence tomography

Optical Review - A dual-path handheld system is proposed for cornea and retina imaging using spectral domain optical coherence tomography. The handheld sample arm is designed to acquire two images...     

Axisymmetric problem of a nonhomogeneous elastic layer

Summary The paper deals with a theoretical treatment of elastic behavior for a medium with nonhomogeneous materials property, which is defined by the relation , i.e., shear modulus of elasticity G varies with the dimensionless axial coordinate by the power product form, arbitrarily. Fundamental differential equation for such nonhomogeneous medium has been already proposed in [5]. It is given by a second-order partial differential equation. However, it was found that the fundamental equation is not sufficient in general to solve several kinds of boundary-value problems. On the other hand, it is shown in the present paper making use of the fundamental equations system for a nonhomogeneous medium, which has been proposed in our previous paper [7], it is possible to solve axisymmetric problems for a thick plate (layer) subjected to an arbitrarily distributed load or a concentrated load on its surfaces. Numerical calculations are carried out for several cases, taking into account the variation of the nonhomogeneous parameter m. The numerical results for displacements stress and components are shown in graphical form. Accepted for publication 25 March 1997     

New developments in the dye-doped polymer dispersed liquid crystals gratings: A review

In this study, the dye-doped polymer dispersed liquid crystals (PDLC) gratings techniques performed by the various research groups or being developed are briefly reviewed. Especially, the electrically switched diffraction and holographic gratings, have attained much attention by various research groups working in the PDLC-related display studies. The fabrication methodologies used for such grating texture, include like the conventional dye-doped PDLC grating, Azo-dye doped PDLC gratings, and lasing techniques etc., adopted for dye-doped PDLC gratings. The useful features and characteristics of their fabrication process of such gratings are discussed. Finally, some of the future perspectives on this particular research field are presented.     

Cationic nucleolipids as efficient siRNA carriers

We synthesized five novel uridine-based cationic nucleolipids, introducing basic amino acid residues at the 5' position of uridine, through 1,3-dipolar cycloaddition, and hydrophobic alkyl moieties at the 2' and 3' positions, through carbamate linkages. Their lipoplexes delivered siRNAs efficiently to cells, in vitro, without any severe toxicity.