The adsorption of ions on electrodes determines the surface potential and charge density of the electrode, thus, quantitative evaluation of the ion adsorption on an electrode is necessary and has been one of the central questions in electrochemistry. Electrochemical Surface Forces Apparatus (EC-SFA) can provide an efficient characterization method of these properties. The interactions between two gold electrodes in various electrolyte solutions, that is, 1 mM aqueous KClO 4 , K 2 SO 4 , and KCl, were measured by controlling of the electrochemical potential (E). The longrange, double layer repulsion and the jump-in due to the van der Waals attraction at the surface separation of about 20 nm were observed between the electrodes in all the solutions. We evaluated the ψ 0 and σ values employing DLVO fitting of these interactions. The signs of ψ 0 and σ were determined from the interaction between the electrode and negatively charged mica surfaces. This study demonstrated that the σ values were negative and similar in all the solutions when the applied potential E was lower than the potential of zero charge (pzc). When the potential E was increased to near the pzc, the σ values were negative and low and in the order of KClO 4 ≈ K 2 SO 4 > KCl. When the potential E was further increased to the pzc, the σ value was positive in aqueous KClO 4 because of less anion adsorption on the gold electrode, while those in the K 2 SO 4 and KCl aqueous solutions were negative due to higher adsorption amount of the anions. The method demonstrated in this study enabled us to quantitatively evaluate the influences of the ion adsorption on the effective surface potential and charge density of the electrodes, which should determine the performances of electrochemical devices.

Acid-base equilibria and effective proton concentration inside a silica mesopore modified with a trimethyl ammonium (TMAP) layer were studied by steady-state fluorescence experiments. The mesoporous silica with a dense TMAP layer (1.4 molecules/nm(2)) was prepared by a post grafting of N-trimethoxysilylpropyl-N,N,N-trimethylammonium at surfactant-templated mesoporous silica (diameter of silica framework =3.1 nm). The resulting TMAP-modified mesoporous silica strongly adsorbed of anionic fluorescence indicator dyes (8-hydroxypyrene-1,3,6-trisulfonate (pyranine), 8-aminopyrene-1,3,6-trisulfonate (APTS), 5,10,15,20-tetraphenyl-21H,23H-porphinetetrasulfonic acid disulfuric acid (TPPS), 2-naphthol-3,6-disulfonate (2NT)) and fluorescence excitation spectra of these dyes within TMAP-modified mesoporous silica were measured by varying the solution pH. The fluorescence experiments revealed that the acid-base equilibrium reactions of all pH indicator dyes within the TMAP-modified silica mesopore were quite different from those in bulk water. From the analysis of the acid-base equilibrium of pyranine, the following relationships between solution pH (pH(bulk)) and the effective proton concentration inside the pore (pH(pore)) were obtained: (1) shift of pH(pore) was 1.8 (ΔpH(pore)=1.8) for the pH(bulk) change from 2.1 to 9.1 (ΔpH(bulk)=7.0); (2) pH(pore) was not simply proportional to pH(bulk); (3) the inside of the TMAP-modified silica mesopore was suggested to be in a weak acidic or neutral condition when pH(bulk) was changed from 2.0 to 9.1. Since these relationships between pH(bulk) and pH(pore) could explain the acid-base equilibria of other pH indicator dyes (APTS, TPPS, 2NT), these relationships were inferred to describe the effective proton concentration inside the TMAP-modified silica mesopore.

Solvation dynamics in alcohols confined in silica nanochannels was examined by time-resolved fluorescence spectroscopy using coumarin 153 (C153) as a fluorescent probe. Surfactant-templated mesoporous silica was fabricated inside the pores of an anodic alumina membrane. The surfactant was removed by calcination to give mesoporous silica (Cal-NAM) containing one-dimensional (1D) silica nanochannels (diameter, 3.1 nm) whose inner surface was covered with silanol groups. By treating Cal-NAM with trimethylchlorosilane, trimethylsilyl (TMS) groups were formed on the inner surface of the silica nanochannels (TMS-NAM). Fluorescence dynamic Stokes shifts of C153 were measured in alcohols (ethanol, butanol, hexanol, and decanol) confined in the silica nanochannels of Cal- and TMS-NAMs, and the time-dependent fluorescence decay profiles could be best fitted by a biexponential function. The estimated solvent relaxation times were much larger than those observed in bulk alcohols for both Cal- and TMS-NAMs when ethanol or butanol was used as a solvent, indicating that the mobility of these alcohol molecules was restricted within the silica nanochannels. However, hexanol or decanol in Cal- and TMS-NAMs did not cause a remarkable increase in the solvent relaxation time in contrast to ethanol or butanol. Therefore, it was concluded that a relatively rigid assembly of alcohols (an alcohol chain) was formed within the silica nanochannels by hydrogen bonding interaction and van der Waals force between the surface functional groups of the silica nanochannels and alcohol molecules and by the successive interaction between alcohol molecules when alcohol with a short alkyl chain (ethanol or butanol) was used as a solvent.

Prostaglandins are thought to play an important role in the proliferation of prostate cancer and are highly expressed in prostate cancer tissue. Cyclooxygenase-2 (COX-2), or prostaglandin endoperoxide synthase, is a key enzyme in the conversion of arachidonic acid into prostaglandin. In several cancers, COX-2 contributes to the proliferation and metastasis of cancer cells. To assess the role of COX-2 in prostate cancer, we investigated whether the inhibition of COX-2 affected the proliferation of prostate cancer cells. The human prostate cancer cell lines, LNCaP and PC 3, and a normal prostate stromal cell line (PrSC) were treated with COX-2 inhibitors NS 398 and Etodolac. The proliferation rate of the cell lines was examined using 3(4,5-dimethylethiazoly 1-2-) 2,5-diphonyl tetrazolium bromide (MTT) assays. A DNA fragmentation assay was also used for proof of apoptosis. COX-2 inhibitors could suppress the proliferation of LNCaP and PC 3 cells. In contrast, PrSC was not affected by COX-2 inhibitors. These suppressive effects occurred in a timeand dose-dependent manner. One of mechanisms responsible for cell death was apoptosis. COX-2 seems to play a significant role in the progression of prostate cancer. COX-2 may be a therapeutic target for prostate cancer. Since COX-2 inhibitors suppress proliferation and induce apoptosis in prostate cancer cells, and have no effect in normal prostate stromal cells, COX-2 inhibitors will be useful for the treatment of prostate cancer.