Proof-of-Principle Experiment for Testing Strong-Field Quantum Electrodynamics with Exotic Atoms: High Precision X-Ray Spectroscopy of Muonic Neon.

To test bound-state quantum electrodynamics (BSQED) in the strong-field regime, we have performed high precision x-ray spectroscopy of the 5g-4f and 5f- 4d transitions (BSQED contribution of 2.4 and 5.2 eV, respectively) of muonic neon atoms in the low-pressure gas phase without bound electrons. Muonic atoms have been recently proposed as an alternative to few-electron high-Z ions for BSQED tests by focusing on circular Rydberg states where nuclear contributions are negligibly small. We determined the 5g_{9/2}- 4f_{7/2} transition energy to be 6297.08±0.04(stat)±0.13(syst) eV using superconducting transition-edge sensor microcalorimeters (5.2-5.5 eV FWHM resolution), which agrees well with the most advanced BSQED theoretical prediction of 6297.26 eV.

Measurements of Strong-Interaction Effects in Kaonic-Helium Isotopes at Sub-eV Precision with X-Ray Microcalorimeters.

We have measured the 3d→2p transition x rays of kaonic ^{3}He and ^{4}He atoms using superconducting transition-edge-sensor microcalorimeters with an energy resolution better than 6 eV (FWHM). We determined the energies to be 6224.5±0.4(stat)±0.2(syst) eV and 6463.7±0.3(stat)±0.1(syst) eV, and widths to be 2.5±1.0(stat)±0.4(syst) eV and 1.0±0.6(stat)±0.3(stat) eV, for kaonic ^{3}He and ^{4}He, respectively. These values are nearly 10 times more precise than in previous measurements. Our results exclude the large strong-interaction shifts and widths that are suggested by a coupled-channel approach and agree with calculations based on optical-potential models.

Deexcitation Dynamics of Muonic Atoms Revealed by High-Precision Spectroscopy of Electronic K X Rays.

We observed electronic K x rays emitted from muonic iron atoms using superconducting transition-edge sensor microcalorimeters. The energy resolution of 5.2 eV in FWHM allowed us to observe the asymmetric broad profile of the electronic characteristic Kα and Kß x rays together with the hypersatellite K^{h}α x rays around 6 keV. This signature reflects the time-dependent screening of the nuclear charge by the negative muon and the L-shell electrons, accompanied by electron side feeding. Assisted by a simulation, these data clearly reveal the electronic K- and L-shell hole production and their temporal evolution on the 10-20 fs scale during the muon cascade process.

Shot Noise of 1,4-Benzenedithiol Single-Molecule Junctions.

We report measurements of the shot noise on single-molecule Au-1,4-benzenedithiol-Au junctions, fabricated with the mechanically controllable break junction (MCBJ) technique at 4.2 K in a wide range of conductance values from 10(-2) to 0.24 conductance quanta. We introduce a simple measurement scheme using a current amplifier and a spectrum analyzer and that does not imply special requirements regarding the electrical leads. The experimental findings provide evidence that the current is carried by a single conduction channel throughout the whole conductance range. This observation suggests that the number of channels is limited by the Au-thiol bonds and that contributions due to direct tunneling from the Au to the π-system of the aromatic ring are negligible also for high conductance. The results are supported by quantum transport calculations using density functional theory.

Energy-level alignments and photo-induced carrier processes at the heteromolecular interface of quaterrylene and N,N'-dioctyl-3,4,9,10-perylenedicarboximide.

Photo-induced carrier processes at the heteromolecular interface of N,N'-dioctyl-3,4,9,10-perylenedicarboximide (PTCDI-C(8)) and quaterrylene (QT) on a molecular scale were examined by optical and photoelectron spectroscopy. The energy level alignments of the molecules were determined by X-ray photoelectron spectroscopy and the optical absorption spectra for detailed investigation of the photo-induced carrier process were analysed. A reduction in photoluminescence from PTCDI-C(8) on QT was observed, clearly demonstrating that the excitons generated in the PTCDI-C(8) layer are effectively dissociated at the heteromolecular interface. One important factor inducing this effective charge dissociation is the highly ordered molecular packing, which acts to increase the exciton diffusion length. Moreover, a specific increase in the photoluminescence excitation spectrum was observed around 3 eV, indicating that simultaneous exciton generation in both the QT and PTCDI-C(8) layers effectively suppresses such charge dissociation of the excitons. In other words, the existence of excitons in each molecule at the heteromolecular interface and HOMO-LUMO level alignment at the interface play an essential role in charge dissociation. Our results provide a striking insight into intermolecular interactions in the carrier process at the heteromolecular interface such as exciton generation, the recombination and dissociation processes, and the photovoltaic effect in organic semiconductors.

Immunological cell situation in the skin of atopic model mice.

BACKGROUND: We observed nishikinezumi, cinnamon-coloured (NC)/Fujita (F) mice aged between 5 and 28 weeks. These NC mice have skin eruptions that resemble human atopic dermatitis (AD) under conventional circumstances. OBJECT: We investigated the skin of eruptive and non-eruptive lesions in NC/F mice by using haematoxylin-eosin (H&E) staining, toluidine blue staining and immunohistopathological study with immunoglobulin (Ig)EepsilonRI, CD23, interleukin (IL)-4, IL-5, interferon (INF)-gamma and Ia antigen. RESULTS: Histological examination of the eruptive lesions revealed the perivascular infiltration of many lymphocytes and mast cells into the upper dermis. Intracellular oedema of the epidermis, lymphocyte infiltration into the epidermis and liquefaction degeneration of the basal layer were also observed. The numbers of IL-4 and IL-5 positive cells in the eruptive lesions were larger than those of the non-eruptive lesions. IL-4 and IL-5 positive cells in the eruptive lesions increased weekly. Some IFN-gamma positive cells were observed in the eruptive lesions after 21 weeks. IFN-gamma positive cells were scarce in the skin of both the non-eruptive and eruptive lesions before 21 weeks. Serum IgE increased from 7 weeks to 21 weeks. DISCUSSION: We confirmed that these findings indicated that T helper (Th)2-dominant immunological activation transformed to a Th1-dominant situation. Many IgEepsilonRI positive cells were recognized in the dermis of the eruptive lesions by the time IgE had decreased. We assumed that the dermatitis before 21 weeks was an IgE-mediated allergy. We have previously reported that older NC/F mice had positive patch-test reactions to mites. Because serum IgE decreased after 21 weeks, dermatitis after 21 weeks might be associated more with cell-mediated delayed hypersensitivity than with IgE-mediated immediate allergy.

Nonlinear dielectric response of antiferroelectric liquid crystals in the smectic C alpha* phase.

Nonlinear dielectric response of antiferroelectric liquid crystals has been studied in the smectic C(alpha)* (SmC(alpha)*) phase. The linear dielectric spectrum shows a single relaxation of Debye type and its relaxation frequency is as high as one hundred kHz. The profile of the third-order nonlinear dielectric spectrum varies in complex fashion with temperature. In the vicinity of the SmA-SmC(alpha)* phase transition, experimentally obtained nonlinear spectra are well described by those calculated with phenomenological theory of Landau type. The soft mode of the SmC(alpha)* phase shows critical slowing-down near the transition temperature. In the lower-temperature region of the SmC(alpha)* phase, the contribution from the soft mode of the SmC(alpha)* phase reduces and the other relaxation mode with Debye-type spectrum appears at several hundred Hz in the nonlinear spectrum. The appearance of this low-frequency mode suggests that the cooperative fluctuation of directors over long range exists in the SmC(alpha)* phase.

Critical behavior of nonlinear permittivity in the smectic-A phase of chiral liquid crystals.

We study the nonlinear permittivity of chiral liquid crystals in the smectic-A (Sm-A) phase near the ferroelectric smectic-C* (Sm-C*) phase and the smectic-C(*)(alpha) (Sm-C(*)(alpha)) phase theoretically and experimentally. The third-order nonlinear permittivity epsilon(3) shows the critical behavior with the exponent of four near the Sm-C* phase and its sign depends on the order of the phase transition. In the case of the Sm-A-Sm-C(*)(alpha) phase transition, the sign inversion of epsilon(3), presumably due to the large fluctuation of order parameter, is observed near the transition temperature.

Electrophoretic microrheology in a dilute lamellar phase of a nonionic surfactant.

We measured the complex electrophoretic mobility mu(*)(omega) of nanometer-sized particles dispersed in a lyotropic lamellar phase, and observed two relaxation processes corresponding to the two characteristic lengths of lamellar structure. Faster relaxation is caused by the distortion field of lamellar phase induced by the colloidal particles, and slower relaxation is presumably due to the defects in lamellar structure. Since the dynamic transport property is strongly influenced by the microscopic circumstances as shown in this paper, this method is referred to as electrophoretic microrheology.

Electro-optic response of a ferroelectric liquid crystal in thick free-standing films.

We study the electro-optic response of a ferroelectric liquid crystal in free-standing films as thick as the helical pitch. In the films thicker than about one pitch, two relaxation modes are observed in the frequency spectra. The relaxation frequency of the slower mode decreases when increasing the film thickness, while that of the faster mode, which appears at approximately 1 kHz, is almost independent of the film thickness. In thinner films, a single relaxation mode is observed at several hundred Hz. The obtained relaxation spectra are discussed in comparison to the theoretical spectra of the phase mode in a system of finite length along the helical axis calculated by Urbanc and Zeks [Phys. Rev. E 52, 3892 (1995)].

Nonlinear dielectric relaxation spectroscopy of ferroelectric liquid crystals

The nonlinear dielectric relaxation spectra of ferroelectric liquid crystals (FLCs) have been studied in the chiral smectic-C phase. The linear and third-order nonlinear dielectric spectra show the relaxation corresponding to the fluctuation in the azimuthal angle of directors called the Goldstone mode. We calculated the nonlinear dielectric spectra of the Goldstone mode theoretically by the torque balance equation which describes the dynamics of FLCs under the electric field. The calculated spectra make good agreement with the measured ones. We also evaluated the material constants of FLCs from the best-fitted values of the linear and nonlinear dielectric increment and relaxation time.

Novel carbon-carbon bond formation reaction of methoxyallene oxide promoted by TiI(4)

Methoxyallene oxide was readily prepared in situ by epoxidation of methoxyallene with 3-chloroperbenzoic acid, and the subsequent reaction with aldehydes or acetals was promoted by titanium tetraiodide and additives to give 2,3-dialkoxy- or 3-hydroxy-2-methoxy ketones in good yields.

Generalizing the debye-Huckel equation in terms of density functional integral

We discuss the validity of generalized Debye-Huckel (GDH) equation proposed by Fisher et al. [B. P. Lee and M. E. Fisher, Phys. Rev. Lett. 76, 2906 (1996); Europhys. Lett. 39, 611 (1997); M. N. Tamashiro, Y. Levin, and M. C. Barbosa, Physica A 268, 24 (1999)], from the functional integral point of view. The GDH theory considers fluctuations around prescribed densities of positive and negative charges. Hence, we first formulate a density functional integral expression for the canonical system of Coulomb gas, and also demonstrate that this is a dual form to the sine-Gordon theory. Our formalism reveals the following: (i) The induced charge distribution around supposed density favors not only the cancellation of additional electrostatic potential like the original DH theory, but also the countervailing of chemical potential difference between imposed and equilibrium value. (ii) As a consequence apparent charge, absent in the GDH equation, comes out in our generalized equation. (iii) That is, the GDH equation holds only in special cases.

Results of patch testing with lavender oil in Japan.

We report the annual results of patch testing with lavender oil for a 9-year period from 1990 to 1998 in Japan. Using Finn Chambers and Scanpor tape, we performed 2-day closed patch testing with lavender oil 20% pet. on the upper back of each patient suspected of having cosmetic contact dermatitis. We compared the frequency of positive patch tests to lavender oil each year with those to other fragrances. We diagnosed contact allergy when patch test reactions were + or <+ at 1 day after removal. The positivity rate of lavender oil was 3.7% (0-13.9%) during the 9-year period from 1990 to 1998. The positivity rate of lavender oil increased suddenly in 1997. Recently, in Japan, there has been a trend for aromatherapy using lavender oil. With this trend, placing dried lavender flowers in pillows, drawers, cabinets, or rooms has become a new fashion. We asked patients who showed a positive reaction to lavender oil about their use of dried lavender flowers. We confirmed the use of dried lavender flowers in 5 cases out of 11 positive cases in 1997 and 8 out of 15 positive cases in 1998. We concluded that the increase in patch test positivity rates to lavender oil in 1997 and 1998 was due to the above fashion, rather than due to fragrances in cosmetic products.

4 cases of photocontact dermatitis due to ketoprofen.

We report 4 cases of photocontact dermatitis due to ketoprofen, a non-steroidal anti-inflammatory drug derived from propionic acid. We carried out a skin biopsy to examine the amount of ketoprofen in the eruptive skin. We investigated the cross-reactions between tiaprofenic acid, suprofen and ketoprofen by patch and photopatch testing. In case no. 1, 17 days after the discontinuance of Mohrus poultice (containing ketoprofen as an active ingredient), we detected ketoprofen 312.5 ng/g in the area of skin where the poultice was applied. All 4 cases reacted positively to the causative medicaments containing ketoprofen and ketoprofen 1% pet. 3 out of 4 cases reacted positively to tiaprofenic acid 1% pet. Only 1 case out of the ketoprofen and tiaprofenic acid positive cases reacted positively to suprofen 1% pet. Vehicles of patients' medicaments were negative in all 4 cases. We suspected that the key structure of the cross-reaction between ketoprofen and tiaprofenic acid and suprofen was the benzoyl radical.

Experimental study on skin sensitization potencies and cross-reactivities of hair-dye-related chemicals in guinea pigs.

In screening patch testing of hairdressers with occupational contact dermatitis, multiple positive reactions to hair dye-related chemicals, such as p-phenylenediamine (PPD), p-toluenediamine x 2HCl (PTD) and p-aminophenol (PAP), a fabric dye p-aminoazobenzene (PAB), and a tar dye Sudan III, were frequently encountered. To investigate individual skin sensitization potency and the cross-reactivities among above chemicals, a guinea pig maximization test with the above 5 chemicals was performed. In each group, 6 animals were induced with one of the chemicals at 0.1% concentration by intradermal injection and at 1.0% by topical application. The animals were challenged with all 5 chemicals in concentrations of dilution by 10 from 0.1% to 0.001%. Under the conditions of 0.1% challenges, similar sensitization potencies were observed in PPD (6/6), PTD (6/6), PAP (5/6) and PAB (6/6) groups, but no positive reactions were elicited in the Sudan III group. The cross-reactivities to PPD were confirmed in the animals challenged with PTD (6/6), PAP (6/6), PAB (6/6) and Sudan III (3/6). In the PTD-induced group, positive responses to cross-challenges were elicited by PPD (5/6), PAP (3/6), PAB (5/6) and Sudan III (1/6). The cross-reactivities to PAP were observed only with PPD (2/5) and PAB (5/5). PAB-induced animals responded only to PPD (1/6). The results indicate that all these chemicals except Sudan III are strong sensitizers. Their cross-reactivities are different in sensitized conditions, respectively. The cross-reactivities to PPD were higher than those to PTD, PAP and PAB.

Rapid, sensitive and simple detection of candida deep mycosis by amplification of 18S ribosomal RNA gene; comparison with assay of serum beta-D-glucan level in clinical samples.

We evaluated the clinical usefulness of a polymerase chain reaction (PCR) assay amplifying the 18S ribosomal RNA gene of fungi for the diagnosis of deep candidiasis, compared with that of the beta-glucan test or Cand-Tec test. Thirty critically ill patients who had received prolonged care with intravenous hyperalimentation and endotracheal intubation in the intensive care unit and were suspected of having deep fungal infections were examined. Twenty-one were fungi positive in the PCR assay (70%). Among 24 samples in which the PCR assay, beta-glucan test and Cand-Tec test were performed simultaneously, 75% of the samples (18/24) were fungi positive in the PCR assay, whereas only 54% (13/24) had positive reactions in the beta-glucan test and 21% (5/24) in the Cand-Tec test. The results of the Cand-Tec test showed no relationship with those of the PCR or beta-glucan test. The lower limit of detection in the PCR assay was 4-5 CFU/ml of C. albicans in blood. No fungal organism was amplified from the serum of 20 healthy individuals. The results of the PCR assay and beta-glucan test showed a significant correlation in this study, but the PCR assay proved to be more sensitive than the beta-glucan test (p < 0.05), and to be more useful for the clinical diagnosis and monitoring of deep Candidiasis.