Several postmortem analyses were conducted to investigate the change of Pt distribution in the active components in a phosphoric acid fuel cell (PAFC) during a long‐term operation. Quantitative analysis of an electron probe microanalyzer (EPMA) indicates not only the loss of Pt in a cathode but also Pt migration to an anode during operation and identifies the Pt in a matrix. It was found that the behavior of Pt during cell operation is associated with operation mode and presumably subsequent singular distribution of phosphoric acid. Observation by transmission electron microscopy (TEM) demonstrates that Pt in an electrode near a matrix grows earlier than that of the center and backing paper side of an electrode. In addition to the results of Pt dissolution, a morphological consideration through TEM gives clear evidence that particle coalescence is also involved in particle growth as sintering mechanism.

Silicon fibers were grown by thermal decomposition of silane at temperatures of 580°–700°C on a silicon substrate which had been contaminated by dust in air or aluminum in HF+NH4F solution. They were a few ten microns in length and a few thousand angstroms in diameter for a growth time of 3 min. According to electron‐diffraction analyses, the fiber is composed of an almost single crystalline pith grown in the direction of <110> by VLS mechanism and an amorphous shell deposited around it.

A simple procedure for chiral separation based on the difference in the molecular weights of the antigen-antibody complex and analyte is developed. We raise monoclonal antibodies (mAbs) highly specific for the R-or S-isomer of a binaphthyl derivative (BN) by immunizing mice with the corresponding BN enantiomer. Aqueous solutions of racemic BN are mixed with mAbs. The free BN is separated by ultrafiltration. The enantiomers of BN are obtained with a high e.e. using atroposelective antibodies.Chirality is crucial in various scientific fields such as pharmaceuticals, [1] chemistry, [2][3][4] and materials science. [5] For example, in pharmaceutical applications employing a specific enantiomer is especially important. Often one enantiomer displays the desired effect, while the other elicits serious side effects. Therefore, chiral separations on both industrial and laboratory scales are important. High-performance liquid chromatography is a popular chiral separation methodology. [6] To date, many researchers have devoted much effort to develop chiral stationary phases (CSPs) such as synthetic polymers, [7] saccharides, [8,9] biomacromolecules, etc. [10][11][12] However, trial and error is still required for developing CSPs. One promising approach toward a straightforward chiral separation strategy is to use antibodies that precisely recognize the chirality of the target molecule. [13] With the advent of cell technology, [14] it is now possible to prepare individual antibodies, monoclonal antibodies (mAbs), in large amounts and in a homogeneous form semi-permanently.Many researchers have developed mAbs against optically active compounds for various purposes. [15][16][17][18][19][20] Among them, the use of mAbs as CSP of immuno affinity chiral columns has been extensively studied. [21] However, harsh elution conditions are necessary due to the high affinity of mAbs against target molecules. Eluting a tightly bound enantiomer while maintaining the stability of mAbs is problematic. [22][23][24] In addition, optimization of the immobilization method of mAbs onto columns is necessary to retain the binding affinity of mAbs. [25] To fully utilize the characteristic of mAbs, a more convenient methodology without columns for chiral separation is necessary.Our research focuses on the basic properties of mAbs, including high specificity for the target molecule and the molecular weight. Unlike chromatographic methods, the high molecular recognition ability of mAb can separate enantiomers with a one-step physical event. The large difference in the molecular weights between the analyte and mAbs realizes the separation of the free analyte by ultrafiltration. In addition, both enantiomers can be obtained by a simple one-step procedure where mAbs are prepared for each enantiomer.Herein, we report a convenient column-free methodology for chiral separation. This study provides insight on how to avoid difficulties when using mAbs. We chose a binaphthyl derivative with axial chirality, which is a well known asymmetric ligand, as a target ...

Auf Si‐Substraten, die durch Staub an der Luft oder durch Al in HF + NH4F‐Lösung kontaminiert wurden, werden durch thermische Zers. von Silan bei 580‐700°C Si‐Fasern gezüchtet.

Chiral recognition of monoclonal antibodies (mAbs) to binaphthyl derivatives (BNs) is visualized utilizing poly-Nisopropylacrylamide (pNIPAM) bearing a BN moiety. The affinity of an anti-BN (S) antibody to BN (S) is retained even when BN (S) is attached to the center of the pNIPAM main chain. The addition of the anti-BN (S) antibody in an atroposelective manner suppresses the aggregation of pNIPAM-BN (S).