Efficient error estimation and adaptive meshing method for boundary element analysis

This paper describes a new and efficient error estimator by using the Direct Regular Method and h or h-r adaptive meshing for BEM analysis. This posteriori error estimator correctly indicates the discretization errors on each element. Based on the error distribution, and the adaptive meshing is generated automatically. The accuracy and convergence of this method are demonstrated by the numerical results on the stress concentration problem and the crack problem.     

Elimination of artifacts on aperture synthesis images using ultrasonic sensor's directivity and the ratio of intensity

Aperture synthesis images using a small number of ultrasonic sensors contain circular or elliptic artifacts. In this letter, to generate clear images less affected by artifacts with the same number of sensors, we propose a method that eliminates these artifacts using sensor's directivity and the ratio of its intensity. The experiments of detecting a plate were performed in terms of estimation of the edge point and the inclination of the plate. Results show that the proposed method can achieve smaller errors than the conventional method. © 2013 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Chemical Synthesis of the Epimeric (23R)‐ and (23S)‐Fluoro Derivatives of Bile Acids via Horner–Wadsworth–Emmons Reaction

A method for the synthesis of two (23R)‐ and (23S)‐epimeric pairs of 23‐fluoro‐3α,7α,12α‐trihydroxy‐5β‐cholan‐24‐oic acid and 23‐fluoro‐3α,7α‐dihydroxy‐5β‐cholan‐24‐oic acid is described. The key intermediates, 23,24‐dinor‐22‐aldehyde peracetates were prepared from cholic and chenodeoxycholic acids via the 24‐nor‐22‐ene, 24‐nor‐22ξ,23‐epoxy, and 23,24‐dinor‐22‐aldehyde derivatives. The Horner–Wadsworth–Emmons reaction of the 23,24‐dinor‐22‐aldehydes using triethyl 2‐fluoro‐2‐phosphonoacetate in the presence of LiCl and 1,8‐diazabicyclo[5,4,0]undec‐7‐ene (DBU), and subsequent hydrogenation of the resulting 23ξ‐fluoro‐22‐ene ethyl esters, followed by hydrolysis, gave a mixture of the epimeric (23R)‐ and (23S)‐fluorinated bile acids which were resolved efficiently by preparative RP‐HPLC. The stereochemical configuration of the fluorine atom at C‐23 in the newly synthesized compounds was confirmed directly by the X‐ray crystallographic data. The ¹H and ¹³C NMR spectral differences between the (23R)‐ and (23S)‐epimers were also discussed.     

Decomposition of a cyanine dye in binary nanosheet colloids of photocatalytically active niobate and inert clay

Binary colloids of inorganic nanosheets prepared by exfoliation of two different layered crystals form phase-separated structures with demixing of the two nanosheets. The phase-separated colloids of photocatalytic niobate and photochemically inert clay nanosheets exhibit unusual photochemical reactions based on the phase-separated structure. The present paper reports photocatalytic decomposition of a cyanine dye in this binary colloid, where the dye is selectively adsorbed on the clay nanosheets to be spatially separated from the photocatalytic nanosheets. Upon UV irradiation, the dye is photocatalytically decomposed in the colloids containing the niobate nanosheets, but self-photolysis of the dye is observed in the colloid lacking the photocatalytic nanosheets. Faster decomposition in nitrogen than in air suggests contribution of the conduction-band electrons generated in the niobate nanosheets to the photocatalytic reaction. In the binary colloid, the degradation is retarded compared with the single-component niobate colloid. Larger clay content more stabilized the dye against the decomposition. In contrast, irradiation of the colloids with visible light causes self-photolysis of the dye even in the presence of the niobate nanosheets, indicating the absence of electron transfer from the photoexcited dye to the photocatalytic nanosheets.     

Cytocompatible and multifunctional polymeric nanoparticles for transportation of bioactive molecules into and within cells

Multifunctional polymeric nanoparticles are materials with great potential for a wide range of biomedical applications. For progression in this area of research, unfavorable interactions of these nanoparticles with proteins and cells must be avoided in biological environments, for example, through treatment of the nanoparticle surfaces. Construction of an artificial cell membrane structure based on polymers bearing the zwitterionic phosphorylcholine group can prevent biological reactions at the surface effectively. In addition, certain bioactive molecules can be immobilized on the surface of the polymer to generate enough affinity to capture target biomolecules. Furthermore, entrapment of inorganic nanoparticles inside polymeric matrices enhances the nanoparticle functionality significantly. This review summarizes the preparation and characterization of cytocompatible and multifunctional polymeric nanoparticles; it analyzes the efficiency of their fluorescence function, the nature of the artificial cell membrane structure, and their performance as in-cell devices; and finally, it evaluates both their chemical reactivity and effects in cells.     

Digital Hilbert transformation for separation measurement of thicknesses and refractive indices of layered objects by use of a wavelength-scanning heterodyne interference confocal microscope

A wavelength-scanning heterodyne interference confocal microscope quickly accomplishes the simultaneous measurement of the thickness and the refractive index of a sample by detection of the amplitude and the phase of the interference signal during a sample scan. However, the measurement range of the optical path difference (OPD) that is obtained from the phase changes is limited by the time response of the phase-locked loop circuit in the FM demodulator. To overcome this limitation and to improve the accuracy of the separation measurement, we propose an OPD detection using digital signal processing with a Hilbert transform. The measurement range is extended approximately five times, and the resolution of the OPD is improved to 5.5 from 9 microm without the electrical noise of the FM demodulator circuit. By applying this method for simultaneous measurement of thickness and the refractive index, we can measure samples 20-30-microm thick with refractive indices between 1 and 1.5.     

Effectiveness of recombinant human serum albumin in the treatment of ascites in liver cirrhosis: evidence from animal model

Autoplex-T is a partially activated prothrombin complex concentrate used primarily for the treatment of patients expressing factor VIII inhibitors. While Autoplex-T has a demonstrated record of clinical effectiveness, the procoagulant composition of this material has not been reported. This absence of composition data is a reflection of the lack of techniques appropriate for accurately measuring an individual protease such as factor IXa in complex mixtures of similar proteases. The development of Colorimetric Active Site-Specific ImmunoAssay technology (CASSIA) has permitted the accurate analysis of the coagulant enzymes present in Autoplex-T. Ten lots of Autoplex-T were reacted with both biotinylated phenylalanylprolylarginine chloromethylketone and biotinylated glutamylglycylarginine chloromethylketone. Only activated forms of the clotting factors present in Autoplex-T react with the peptide chloromethylketones and were thus separated from the other proteins present in Autoplex-T by adsorption onto streptavidin. The individual proteins bound to streptavidin were then detected with specific antibodies. Mean results from the analysis of ten lots of Autoplex-T (mean values) are as follows: factor Xla, 5.9 nM or 0.8 microg/ml; factor Xa, 46.5 nM or 2.1 microg/ml; factor IXa, 177.8 nM or 11.7 microg/ml; factor VIIa, 68.6 nM or 3.3 microg/ml and factor IIa, 5.3 nM or 0.2 microg/ml. These results are discussed with respect to the mechanism of action of Autoplex-T in the treatment of factor VIII inhibitor patients.     

Development of a recombinant ε-poly-L-lysine synthetase expression system to perform mutational analysis

ε-Poly-L-lysine (ε-PL) synthetase (Pls), which is a membrane protein with adenylation and thiolation domains characteristic of the nonribosomal peptide synthetases, catalyzes polymerization of L-lysine molecules (25-mer to 35-mer). Here, we report on the development of a recombinant Pls expression system that allowed us to perform a site-directed mutational analysis.