Hypervalent iodine(III): selective and efficient single-electron-transfer (SET) oxidizing agent

In 1994, we first determined the single-electron-transfer (SET) oxidation ability of phenyliodine(III) bis(trifluoroacetate) (PIFA) toward phenyl ethers, affording the corresponding aromatic cation radicals. Since then, hypervalent iodine(III) has been utilized as a selective and efficient SET oxidizing agent that enables a variety of direct C-H functionalizations of aromatic rings in electron-rich arenes under mild conditions. We have now extended the original method to work in a series of heteroaromatic compounds such as thiophenes, pyrroles, and indoles. The investigations and results obtained since the start of this century are summarized in this article.     

Nanoimaging and spectroscopic analysis of rubber/ZnO interfaces by energy-filtering transmission electron microscopy

Energy-filtering transmission electron microscopy (EFTEM) was employed for investigating interactions between rubber and ZnO particles in the accelerated vulcanization process. Combining elemental mapping and electron energy loss spectroscopy (EELS) by EFTEM enabled the characterization of the interfaces with spatial resolutions of less than 10 nm and with high elemental detection sensitivity. We found that a sulfur- and zinc-rich compound was generated around ZnO particles, and that product was then revealed to be ZnS-generated as a byproduct in the accelerated vulcanization process. Through this study, it is indicated that the accelerated vulcanization with ZnO does not occur uniformly in the rubber matrix; it occurs locally around ZnO particles at a higher reaction rate, implying that the rubber network structure is not uniform on the nanoscale.     

Facile preparation of aromatic ketones from aromatic bromides and arenes with aldehydes

Aromatic ketones were efficiently prepared in good yields by the reactions of aryl bromides with n-BuLi, followed by the reactions with aromatic aldehydes or aliphatic aldehydes and the subsequent treatment with molecular iodine and K₂CO₃, in a one-pot method. The same treatment of arenes, instead of aromatic bromides, also provided the corresponding aromatic ketones in good yields. Using these methods, various diaryl ketones and alkyl aryl ketones bearing electron-rich aromatics and electron-deficient aromatics could be prepared efficiently by a simple, transition-metal-free, and therefore environmentally benign experimental procedure.     

Software Release Games

The software release game developed in Ref. 1 is reconsidered in the framework of a two-person nonzero-sum game of timing. More precisely, noisy-type software release strategies are derived in closed form under two different criteria as well as an alternative silent-type software release strategy. Our method overcomes the fatal problem in Ref. 1 and has an advantage on computational tractability. Also, the method can be extended directly to obtain noisy-type strategies.     

Molecular design and biological potential of galacto-type trehalose as a nonnatural ligand of shiga toxins

Galacto-type trehalose, a "C-4 epimer of trehalose", possesses a stereochemical structure around the alpha(1-1)-linkage analogous to that of the globobiosyl alpha(1-4)-linkage in Gb(2) and Gb(3) ceramides, which are known as the ligands of Shiga toxins produced by pathogenic E. coli. This paper presents evidence supporting the new idea of using a trehalosyl alpha(1-1)-linkage as a substitute for the galactobiosyl alpha(1-4)-linkage.     

Inspection scheduling for imperfect production processes under free repair warranty contract

The paper considers scheduling of inspections for imperfect production processes where the process shift time from an ‘in-control’ state to an ‘out-of-control’ state is assumed to follow an arbitrary probability distribution with an increasing failure (hazard) rate and the products are sold with a free repair warranty (FRW) contract. During each production run, the process is monitored through inspections to assess its state. If at any inspection the process is found in ‘out-of-control’ state, then restoration is performed. The model is formulated under two different inspection policies: (i) no action is taken during a production run unless the system is discovered in an ‘out-of-control’ state by inspection and (ii) preventive repair action is undertaken once the ‘in-control’ state of the process is detected by inspection. The expected sum of pre-sale and post-sale costs per unit item is taken as a criterion of optimality. We propose a computational algorithm to determine the optimal inspection policy numerically, as it is quite hard to derive analytically. To ease the computational difficulties, we further employ an approximate method which determines a suboptimal inspection policy. A comparison between the optimal and suboptimal inspection policies is made and the impact of FRW on the optimal inspection policy is investigated in a numerical example.     

A dual transformation between SO(n + 1) and SO(n, 1) and its geometric applications

There is a dual transformation between SO(n + 1)?{(00-component) = 0} and SO(n, 1). This transformation makes clear the relations how orthogonal axes look like in two spaces, Euclidean space and Minkowski space.     

Percutaneous absorption of indomethacin from mixtures of fatty alcohol and propylene glycol (FAPG bases) through rat skin: effects of oleic acid added to FAPG base

The effects of oleic acid (OA) added to mixtures of fatty alcohol and propylene glycol (FAPG bases) on the percutaneous absorption of indomethacin (ID) were investigated by using the abdominal skin of rats in vivo. The percutaneous absorption of propylene glycol (PG) from FAPG base was simultaneously examined. The percutaneous absorption of ID from FAPG bases in the absence of OA was poor as compared with that from FAPG bases containing OA. It was observed that when OA was added to the vehicles in the range of 5 to 30%, the percutaneous absorption of ID from the vehicles was increased. In particular, the maximal enhancement of percutaneous absorption of ID was achieved at 5% OA. However, the enhancing effect of percutaneous absorption of ID diminished when the OA content in the vehicle exceeded 50%. PG was readily absorbed through the rat skin from FAPG bases and its percutaneous absorption profiles were similar to those of ID. It can be presumed that PG and ID penetrate together through the skin. In addition, it was confirmed that the percutaneous absorption of ID and PG from FAPG bases was not affected by the viscosity of the vehicle. If FAPG base is to be used as a vehicle for the purpose of percutaneous absorption of ID, OA is considered to be a useful additive.     

Enhancing effect of cetyl lactate on the percutaneous absorption of indomethacin in rats

The enhancing effect of cetyl lactate (CL) on the percutaneous absorption of indomethacin (ID) from test solutions in propylene glycol (PG) was investigated by using the abdominal skin of rats in vivo. The percutaneous absorption rate of ID from 1 or 3% CL-PG test solution through the intact skin of rats was observed to be faster than that from the control solution (without CL). The bioavailability of ID was about 0.04% for the control solution, 2.2% for 1% CL-PG and 6.8% for 3% CL-PG test solutions. These results suggest that CL functions as an enhancer for the percutaneous absorption of ID. Furthermore, marked enhancing effects on percutaneous absorption of ID were obtained at a concentration greater than 1% CL in PG. In order to elucidate the mode of action of CL as an absorption enhancer, the percutaneous absorption of ID from the control solution and 3% CL-PG test solution through damaged skin from which the stratum corneum had been stripped was additionally investigated. It was confirmed that CL acts on the stratum corneum to produce its effect.