PHOTOALLERGIC CONTACT DERMATITIS TO MUSK AMBRETTE: ACTION SPECTRA IN GUINEA PIGS AND MAN*

Abstract— Positive photopatch tests to musk ambrette were elicited using narrow band radiation in two patients with photoallergic contact dermatitis to musk ambrette and in photosensitized guinea pigs. The most effective wavelength range in the two patients was between 334 and 394 nm. Control subjects did not respond to the same light doses either in the presence or absence of musk ambrette. One patient exhibited maximum sensitivity at 346 nm. The action spectrum in guinea pigs extended from 322 to 406 nm with maximum response at 322 nm. Below 322 nm, erythema was observed at the same or higher doses than those required for evoking a minimal erythema response in non-sensitized animals. Morphologically and histologically the response below 322 nm appeared to be normal delayed erythema. No erythema was elicited by radiation between 322 and 430 nm in non-photosensitized animals which had received musk ambrette.     

Contrasting photochemical bridging regioselectivity in bridgehead-substituted 9,10-etheno- vs. 9,10-(o-benzeno)-9,10-dihydroanthracenes

The two series of title compounds show contrasting bridging regioselectivity with respect to the bridgehead substituents and are suggested to have different stages of the reactions which determine the ultimate pathway.     

Preparation and block copolymerization of oligodihexanoylchitin having hydroxy groups at both ends

The preparation of oligodihexanoylchitin (3) having hydroxy groups at the both ends was carried out by an acid hydrolysis of a parent dihexanoylchitin in a mixed solution of acetic acid and conc. hydrochloric acid (11 : 1 in volume) at a room temperature. After 13–21 h, the products were isolated and their molecular weights were calculated as 7400–1100 by GPC analyses. The structure of the product 3 was determined by ¹H and ¹³C-NMR and IR spectra. The IR spectra of the products yielded for longer hydrolysis times than 30 h, however, indicated the occurrence of the dehexanoylation. The block copolymerization of 3 with poly (propylene glycol) (PPG) using 4,4'-methylenedi (phenyl isocyanate) (MDI) as a coupling reagent gave the block copolymer 6 . The molecular weight of 6 as obrained by GPC was 52,000. © 1994 John Wiley & Sons, Inc.     

Preparation of CuO nanoparticles by metal salt-base reaction in aqueous solution and their metallic bonding property

This article describes a method for preparing CuO nanoparticles in aqueous solution, and a demonstration of feasibility of metallic bonding with the use of the CuO particles. Colloid solution of CuO nanoparticles was prepared from Cu(NO₃)₂ aqueous solution (0.01 M) and NaOH aqueous solution (0.019 M) at 5–80 °C. Leaf-like aggregates with an average size of 567 nm composed of CuO nanoparticles were produced at 20 °C. The size of leaf-like aggregates decreased with increasing reaction temperature. Metallic copper discs could be bonded using the CuO nanoparticles under annealing at 400 °C and pressurizing at 1.2 MPa for 5 min in H₂ gas. A shear strength required for separating the bonded discs was 25.4 MPa for the CuO nanoparticles prepared at 20 °C, whose aggregates were the largest among the CuO particles examined. These results indicated that the formation of leaf-like aggregates of CuO nanoparticles led to efficient metallic bonding.     

Fabrication of asymmetric molecular junctions by the oriented assembly of dithiocarbamate rectifiers

The oriented assembly of molecules on metals is a requirement for rectification in planar metal-molecule-metal junctions. Here, we demonstrate how the difference in adsorption kinetics between dithiocarbamate and thioacetate anchor groups can be utilized to form oriented assemblies of asymmetric molecules that are bound to Au through the dithiocarbamate moiety. The free thioactate group is then used as a ligand to bind Au nanoparticles and to form the desired metal-molecule-metal junction. Besides allowing an asymmetric coupling to the electrodes, the molecules exhibit an asymmetric molecular backbone where the length of the alkyl chains separating the electrodes from a central, para-substituted phenyl ring differs by two methylene units. Throughout the junction fabrication, the layers were characterized by photoelectron spectroscopy, infrared spectroscopy, and scanning tunneling microscopy. Large area junctions using a conducting polymer interlayer between a mercury-drop electrode and the self-assembled monolayer prove the relationship between electrical data and molecular structure.     

Lewis acid-promoted reaction of β,γ-unsaturated α,α-dimethoxy esters with silyl nucleophiles

The Lewis acid-promoted reaction of β,γ-unsaturated α,α-dimethoxy esters, which are easily prepared by the acetalization of β,γ-unsaturated α-keto esters, with silyl nucleophiles is presented. By employing trimethylsilyl enolate and allyltrimethylsilane as nucleophiles, the BF₃-promoted reactions of a series of β,γ-unsaturated α,α-dimethoxy esters bearing aromatic and aliphatic substituents proceeded at the γ-position in an SN2′ manner to furnish γ-substituted α,β-unsaturated α-methoxy esters in good yields with high regioselectivity. In contrast, the reaction using trimethylsilyl cyanide predominantly occurred at the α-position, and the reaction of silyl hydride resulted in a mixture of α- and γ-regioisomers in favor of the γ-substitution products.     

Regioselectivity control of photodimerization of liquid-crystalline cinnamoyl compounds by phase variation: dual functionality of p-terphenyl substituent as a mesogen and a triplet sensitizer

Cinnamoyl-functionalized liquid-crystalline (LC) compounds having a 4″-substituted [1,1′;4′,1″]terphenyl (p-terphenyl) as mesogens were synthesized to investigate the abilities of the mesogen to act as a triplet sensitizer. UV (365 nm) irradiation of the LC compound having 4″-cyano-p-terphenyl in the crystalline and LC phases regioselectively produced the photodimers with a head-to-tail and a head-to-head cyclobutane unit, respectively. The p-terphenyl thus played the role of triplet sensitizer because the cinnamoyl group does not absorb 365 nm light. Due to the dual functionality of the p-terphenyl as the mesogen and the triplet sensitizer, we successfully performed the photochemical and regioselective cycloaddition to obtain two different LC dimers from one LC monomer.     

Measurement of longitudinal single spin asymmetry of W ± → μ± at forward/backward rapidities with PHENIX at √s = 500–510 GeV polarized p + p collisions

The PHENIX experiment has collected about 25 pb^?1 longitudinally polarized p + p collisions at √s = 500 GeV in 2011 run for probing antiquark polarization. In this talk the first preliminary result of A _L ^μ± is presented.     

Nonenzymatic glucose fuel cells with an anion exchange membrane as an electrolyte

Nonenzymatic glucose fuel cells were prepared by using a polymer electrolyte membrane and Pt-based metal catalysts. A fuel cell with a cation exchange membrane (CEM), which is often used for conventional polymer electrolyte fuel cells, shows an open circuit voltage (OCV) of 0.86 V and a maximum power density (P_max) of 1.5 mW cm^?2 with 0.5 M d-glucose and humidified O₂ at room temperature. The performance significantly increased to show an OCV of 0.97 V and P_max of 20 mW cm^?2 with 0.5 M d-glucose in 0.5 M KOH solution when the electrolyte membrane was changed from a CEM to an anion exchange membrane (AEM). This is due to the superior catalytic activity for both glucose oxidation and oxygen reduction in alkaline medium than in acidic medium. The anodic reaction of the fuel cell can be estimated to be the oxidation of glucose to gluconic acid via a two-electron process under these experimental conditions. The crossover of glucose through an electrolyte membrane was negligibly small compared with methanol and may not represent a serious technical problem due to the cross-reaction.