Capillary electrophoretic determination of self-dimerization constants of aromatic carboxylate and sulfonate ions.

Self-dimerizations of twenty three aromatic carboxylate and sulfonate ions from their electrophoretic mobilities in aqueous solution were estimated by capillary zone electrophoresis (CZE). The magnitudes of the self-dimerizations ascribed to pi-pi interactions of these aromatic anions were determined by CZE as dimerization constants (KD). Although the largest KD value of 1.2 dm3 mol(-1) for 9-anthracenecarboxylate ion (9-AC) in these aromatic anions was found, almost all of the KD values were zero, or near to zero. It was found that the pi-pi interactions of the aromatic anions were relatively small at zero ionic strength, in which the contribution of an ionic association between the cation and aromatic anions could be excluded from the KD values, since the contribution of the electric repulsion between the aromatic anions on the KD values was large. The relatively large KD value of 9-AC caused that it electro-migrates as its planar shape, and has an anthracene ring of a largely hydrophobic aromatic ring.     

Tunable quantum dot resonator embedded in a quantum wire

Combined quantum wire and quantum dot system is theoretically predicted to show unique conductance properties associated with Coulomb interactions. We use a split gate technique to fabricate a quantum wire containing a quantum dot with two tunable potential barriers in a two-dimensional electron gas. We observe the effects of the quantum dot cavity on the electron transport through the quantum wire, such as Coulomb oscillations near the pinch-off voltage and periodic conductance oscillations on the first conductance plateau.     

Design of peptide that recognizes double-stranded DNA.

A novel molecular tool for double-stranded (ds) DNA detection using synthetic peptide is described. The peptide was designed based on the DNA binding domain of the lambda phage CRO repressor (CRO). The designed peptides contain helix-turn-helix (HTH), which is DNA binding motif. A cyclic peptide and a mutant peptide based on CRO were also designed, and the resulting affinity for dsDNA was increased. Furthermore, native amino acids of the peptide were replaced with arginine to increase the affinity for dsDNA. The affinity of these peptides for DNA binding was assessed by surface plasmon resonance (SPR) technique.     

Phase behaviour of three homologues of the discotic hexa-n-alkoxyanthraquinones under pressure

The phase transition behaviour of three homologous discotic mesogens, the hexa-n-alkoxyanthraquinones HOAQ(n), n indicating the number of carbon atoms in the alkoxy group, was investigated under hydrostatic pressures up to 500 MPa using a high pressure differential thermal analyser. The T vs. P phase diagrams of HOAQ(6), HOAQ(8) and HOAQ(9) were constructed for solution- (Cr₀) and melt-crystallized (Cr₁) samples of the compounds. HOAQ(6) shows the reversible Cr₀-rectangular columnar phase (Col_r)-hexagonal columnar phase (Col_h)-isotropic liquid (I) phase sequence at atmospheric pressure. The stable Col_r phase of HOAQ(6) has a decreased temperature range with increasing pressure and then the Col_r phase disappears under pressures above about 350 MPa; instead the Cr₀-Col_h-I phase sequence is exhibited. For HOAQ(8), the solution-grown sample exhibits the stable Cr₀-Col_h-I phase sequence at atmospheric pressure. Applying pressure to the solution-grown sample induces the formation of the stable Col_r phase in the pressure region between 10 and 350 MPa, leading to the Cr₀-Col_r-Col_h-I phase sequence. The pressure-induced Col_r phase disappears under higher pressures. The melt-cooled sample of HOAQ(8) shows the formation of the metastable crystal (Cr₁), unknown mesophase (X) and Col_r phases at lower temperatures under atmospheric pressure, and exhibits the reversible Cr₁-X-Col_r-Col_h-I phase sequence on subsequent thermal cycles. The metastable phase sequence was observed under pressures up to 100 MPa, but the phase transitions were too small to be detected under higher pressures. In HOAQ(9) the stable Cr₀-Col_h-I phase sequence is observed at all pressures, while the melt-cooled sample shows the metastable Cr₁-Col_r-Col_h-I phase sequence under pressures up to 300 MPa. The metastable Col_r phase disappears under higher pressures.     

Near-Extremal Formally Self-Dual Even Codes of Lengths 24 and 32

The weight enumerator of a formally self-dual even code is obtained by the Gleason theorem. Recently, Kim and Pless gave some restrictions on the possible weight enumerators of near-extremal formally self-dual even codes of length divisible by eight. In this paper, the weight enumerators for which there is a near-extremal formally self-dual even code are completely determined for lengths 24 and 32, by constructing new near-extremal formally self-dual codes. We also give a classification of near- extremal double circulant codes of lengths 24 and 32. Communicated by: P. Fitzpatrick     

Use of Three‐Dimensional Arterial Models To Predict the In Vivo Behavior of Nanoparticles for Drug Delivery

Nanomaterials have been widely used for applications in biomedical fields and could become indispensable in the near future. However, since it is difficult to optimize in vivo biological behavior in a 3D environment by using a single cell in vitro, there have been many failures in animal models. In vitro prediction systems using 3D human‐tissue models reflecting the 3D location of cell types may be useful to better understand the biological characteristics of nanomaterials for optimization of their function. Herein we demonstrate the potential ability of 3D engineered human‐arterial models for in vitro prediction of the in vivo behavior of nanoparticles for drug delivery. These models enabled optimization of the composition and size of the nanoparticles for targeting and treatment efficacy for atherosclerosis. In vivo experiments with atherosclerotic mice suggested excellent biological characteristics and potential treatment effects of the nanoparticles optimized in vitro.     

Dynamics of Photoelectrons and Structural Changes of Tungsten Trioxide Observed by Femtosecond Transient XAFS

The dynamics of the local electronic and geometric structures of WO₃ following photoexcitation were studied by femtosecond time‐resolved X‐ray absorption fine structure (XAFS) spectroscopy using an X‐ray free electron laser (XFEL). We found that the electronic state was the first to change followed by the local structure, which was affected within 200 ps of photoexcitation.     

Multivariable Euler transform of systems of linear ordinary differential equations of Okubo normal form

The multivariable Euler transform of a solution of the system of linear ordinary differential equations of Okubo normal form is considered. The Pfaffian system satisfied by the transform is derived. Applications to the Appell hypergeometric functions \(F_{1}\), \(F_{3}\), and the Lauricella hypergeometric function \(F_{D}\) are given.     

Solubility of GaN in supercritical ammonia with ammonium chloride as a mineralizer

The solubility of GaN in supercritical ammonia with ammonium chloride as a mineralizer was measured with a weight-loss method. Temperature-, pressure-, and mineralizer concentration-dependence of the solubility of GaN were investigated. The solubility increased with increase in temperature, and its pressure dependence was very low. The solubility behavior was quite different from the case of using the mineralizer KNH₂ as a basic mineralizer.