Self-assembly and subsequent accumulation of lipid nanotubes at oil/water interfaces.

We utilized oil/water interfaces as a new field to produce lipid nanotubes (LNTs), which are formed by the self-assembly of lipid molecules, and possess hollow nanometer-wide cylindrical structures. Compared to the self-assembling field in bulk water, oil/water interfaces produced shorter lipids nanotubes less than 10 microm long more efficiently. In addition, we found that the oil/water interface accumulates lipid nanotubes spontaneously. This methodology is favorable to fabricate LNTs as new nano-fluidic devices, or sensors that require accumulation and alignment in two dimensions.     

Transient reflecting grating for sub-surface analysis: GHz ultrasonic and thermal spectroscopies and imaging

Picosecond time-resolved Transient Reflecting Grating (TRG) measurements are demonstrated for GHz ultrasonic and thermal spectroscopies of thin films and sub-surface regions of sub-m scale. The measurements should be tools for electrochemical interface monitoring and time-resolved imaging. Some results are presented to show ion-implantation-induced surface hardening and unusual heat-diffusion behavior near a silicon surface. A model describing potential dependence of TRG responses at an electrochemical interface is proposed. An image of photoexcited carrier density is compared with a thermal image for a He-ion-implanted silicon wafer to demonstrate the time-resolved imaging.     

Chemical synthesis of 23 kDa glycoprotein by repetitive segment condensation: a synthesis of MUC2 basal motif carrying multiple O-GalNAc moieties

Peptide thioester corresponding to a MUC2 tandem repeat unit, which retains seven GalNAc moieties, was prepared by the Fmoc method followed by the low TfOH treatment to remove benzyl groups at the carbohydrate portions. The glycosylated peptide thioester was then consecutively joined by the activation of a thioester group by silver ions to obtain a MUC2 tandem repeat model composed of 141 amino acids with 42 GalNAc moieties.     

Asymmetric activation of chiral alkoxyzinc catalysts by chiral nitrogen activators for dialkylzinc addition to aldehydes: super high-throughput screening of combinatorial libraries of chiral ligands and activators by HPLC-CD/UV and HPLC-OR/RIU systems

Asymmetric catalysts, prepared by chiral ligand exchange or chiral modification, can evolve further into highly activated catalysts through engineering with chiral activators. Two new methodologies for "super high-throughput screening" (SHTS) of chiral ligands and activators have been developed as a combination of HPLC-CD/UV (CD/ UV = circular dichroism/ultraviolet spectroscopy) or -OR/RIU (OR/RIU = optical rotation/refractive index unit) with a combinatorial chemistry (CC) factory. With these techniques, the % ee of the product is determined within minutes without separation of the enantiomeric products by using a nonchiral stationary phase. Therefore, those SHTS techniques combined with our 'asymmetric activation' concept can provide a powerful strategy for finding the best activated chiral catalyst.     

Preparation of Lead-Calcium Hydroxyapatite Solid Solutions by a Wet Method Using Acetamide

Lead-calcium hydroxyapatite solid solutions with different Pb/(Pb+Ca) molar ratios (X_Pb) were prepared by a wet method using acetamide (AA). The crystal phase and structure of the products depended on the aging period (t_a), Pb/(Pb+Ca) molar ratio ([X_Pb]), and AA concentration ([AA]) of the starting solution. At [AA]=1.6 mol dm⁻³ and t_a=6 days, the large needle-like PbCaHap particles were formed from solutions at [X_Pb]=0-0.6 and 0.9-1. Under the other AA concentrations and aging periods, pure PbCaHap particles could be obtained in a narrower region of [X_Pb]; e.g., PbCaHap was formed from solutions at [AA]=0.8 mol dm⁻³, t_a=6 days, and [X_Pb]= 0-0.1, 0.4-0.5, and 0.9-1.