Utilization of the pleiotropy of a peptidic aptamer to fabricate heterogeneous nanodot-containing multilayer nanostructures

Peptide aptamers (=binders) against inorganic materials often show a capacity for mineralization of their target atoms; thus they are able to function both as binding molecules and as mediators for mineralization. Although the mechanisms underlying these two properties of peptide aptamers are not yet fully understood, they have been used separately to fabricate various nanostructures. Here, we present a novel method of nanofabrication, in which binding and mineralization by a peptide aptamer are alternately utilized to assemble multilayered nanostructures comprised of metal loaded cage proteins ornamented with Ti-binding peptides.     

Eicosapentaenoic acid release from the red alga Pachymeniopsis lanceolata by enzymatic degradation

Forty-eight species of seaweeds from Japanese waters were screened for the valuable polyunsaturated fatty acids eicosapentaenoic acid (EPA). The eight species that contained the highest levels of these compounds were analyzed in detail. Of all species tested the red alga Pachymeniopsis lanceolata contained the highest EPA concentration, and it was present as both the free and bound forms. EPA constituted 38.7% of total fatty acids, and polar lipids were the main constituent of the total lipids in P. lanceolata. EPA was obtained from the marine algae P. lanceolata by enzymatic hydrolysis of the total lipids extract using phospholipase A₂(PLA₂). The release of EPA reached a plateau after 10 min of enzymatic treatment. These results suggest that P. lanceolata is a useful natural source of EPA and that PLA₂ treatment is a convenient method for obtaining EPA from the red alga.     

Evaluation of asymmetrical structure dialysis membrane by tortuous capillary pore diffusion model

The tortuous capillary pore diffusion model (TCPDM) has been used for estimating diffusive and pure water permeability from simple structure parameters such as pore diameter, surface porosity, wall thickness and tortuosity. The validity of this model for evaluation of homogeneous membrane has been already confirmed. Recently, there is a trend toward the use of asymmetrical dialysis membranes made of synthetic polymer such as poly(acrylonitrile) (PAN), polysulfone (PS) and a polyethersulfone polyarylate (PEPA) blend polymer. The purpose of the present study is to apply the TCPDM to evaluation of commercially available hollow-fiber dialysis membranes with asymmetrical structures by simplifying them to a double-layer membrane. The TCPDM is capable of estimating pore tortuosity of asymmetrical dialysis membranes having skin and supporting layers from data on membrane thickness, pore diameter, pure water permeability and water content. Values for diffusive permeability obtained by the TCPDM are in a good agreement with experimental data. This TCPDM model is useful for evaluation of not only homogeneous membrane but also asymmetrical membrane.     

Phomactin H, a novel diterpene from an unidentified marine-derived fungus

Phomactin H (1), a diterpene has been isolated from cultures of an unidentified marine-derived fungus. The structure and relative stereochemistry of phomactin H (1) was determined by X-ray diffraction analysis. Phomactin H (1), having an oxepane moiety, is a new phomactin with a novel skeleton.     

Thermodynamic and Spectroscopic Study of the Adduct Formation of Tris(β-diketonato)lanthanoids with Heteroamines

A remarkable enhancement of the extraction of lanthanoids(Ⅲ)(Ln) with β-diketones in the presence of a Lewis base, so-called synergistic effects, would be caused by the adduct formation of the β-diketonates with the Lewis base. The trend of the variation of the adduct formation constants across the lanthanoid series may be different among β-diketones used. It has also been observed that the trend across lanthanoid series and also the values of the enthalpy change in the adduct formation of the 2-thenoyltrifluoroacetonates(TTA) with 1,10-phenanthroline(phen) are very similar to those with 2,25-bipyridyl(bpy), although the values of the adduct formation constants with the former are larger than those with the latter.     

Thermal modulated interaction of aqueous steroids using polymer-grafted capillaries

Poly(N-isopropylacrylamide) (PIPAAm) of controlled molecular weight was densely grafted onto glass capillary lumenal surfaces using surface-initiated atom transfer radical polymerization (ATRP). Temperature-dependent changes of these thermoresponsive brush surfaces with hydrophobic steroids were investigated by exploiting thermoresponsive aqueous wettability changes of the polymer-modified surfaces in microfluidic systems. IPAAm was polymerized on ATRP initiator-immobilized glass surfaces using CuCl/CuCl(2)/tris(dimethylaminoethyl)amine (Me(6)TREN) as an ATRP catalyst in water at 25 degrees C. PIPAAm graft layer thickness and its homogeneity on glass surfaces are controlled by changing ATRP reaction time. Aqueous wettability changes of PIPAAm-grafted surfaces responses drastically changed to both grafted polymer layer thickness and temperature, especially at lower temperatures. Temperature-responsive surface properties of these PIPAAm brushes within capillary inner wall surfaces were then investigated using capillary chromatography. Effective interaction of hydrophobic steroids with dehydrated, hydrophobized PIPAAm-grafted capillary surfaces was observed above 30 degrees C without any column packing materials. Steroid elution behavior from PIPAAm-grafted capillaries contrasted sharply with that from PIPAAm hydrogel-grafted porous monolithic silica capillaries prepared by electron beam (EB) irradiation wherein significant peak broadening was observed at high-temperature regardless of sample hydrophobicity factors (log P values), indicating multistep separation modes in coated monolithic silica capillaries. In conclusion, thermoresponsive polymer-grafted capillary inner wall surfaces prepared by ATRP exhibit useful temperature-dependent surface property alterations effective to regulate interactions with biomolecules without requirements for separation bed packing materials within the capillary lumen.     

AES studies on the Ti/N compositionally gradient film deposited onto Ti-6Al-4V alloy by reactive DC sputtering.

Deposition of Ti/N compositionally gradient film onto Ti-6Al-4V alloy substrates was carried out by reactive DC sputtering, not only to improve the blood compatibility of the alloy but also to relax the stress concentrated at the interface between the film and the alloy substrate. The compositional gradient was realized by varying continuously the nitrogen content in Ar-N2 sputter gas during deposition. In Auger electron spectroscopy (AES) analysis, Auger spectra were acquired in the N(E) mode using the beam brightness modulation (BBM) method to overcome the problem of the peak overlap of the principal Auger nitrogen transition peak (N-KLL) with one of titanium peaks (Ti-LMM). The deposited film appeared to be uniform and adhesive. TiN formation at the surface of the film was assumed, because of its yellow gold color and the X-ray diffraction (XRD) pattern for it. Under scanning electron microscopy, it was found that the surface had fine particles dispersed on a smooth accumulated deposit and that this depositing method improved the structural property of the film at the surface. According to AES in-depth profiles, the nitrogen (N) concentration in the film gradually decreased in the depth direction from the surface toward the alloy, confirming that a Ti/N compositionally gradient film had formed on the alloy substrate.