Relieving Depression Through Emotional Contagion

Emotional contagion is a phenomenon by which an individual’s emotions directly trigger similar emotions in others. We explored the possibility that perceiving others’ emotional facial expressions affect mood in people with subthreshold depression (sD). Around 49 participants were divided into the following four groups: participants with no depression (ND) presented with happy faces; ND participants presented with sad faces; sD participants presented with happy faces; and sD participants presented with sad faces. Participants were asked to answer an inventory about their emotional states before and after viewing the emotional faces to investigate the influence of emotional contagion on their mood. Regardless of depressive tendency, the groups presented with happy faces exhibited a slight increase in the happy mood score and a decrease in the sad mood score. The groups presented with sad faces exhibited an increased sad mood score and a decreased happy mood score. These results demonstrate that emotional contagion affects the mood in people with sD, as well as in individuals with ND. These results indicate that emotional contagion could relieve depressive moods in people with sD. It demonstrates the importance of the emotional facial expressions of those around people with sD such as family and friends from the viewpoint of emotional contagion

Correlated polarization dependences between surface-enhanced resonant Raman scattering and plasmon resonance elastic scattering showing spectral uncorrelation to each other

We investigated the origin of the identical polarization angle dependences between surface-enhanced resonant Raman scattering (SERRS) and plasmon resonance for two types of single silver nanoparticle aggregates. The first type (Type I), in which the SERRS spectral envelopes are similar to the plasmon resonance elastic scattering spectra, shows the identical polarization dependence between the SERRS and plasmon resonance. The second type (Type II), in which the SERRS envelopes largely deviate from the plasmon resonance, also exhibits identical polarization dependence. Scanning electron microscopy (SEM) observations indicated that these aggregates were dimers. Thus, this unintuitive result was examined by calculating the electromagnetic (EM) enhancement by changing the morphology of the dimers. The calculation revealed that Type I of dimer generates SERRS directly by superradiant plasmons. The Type II of dimer generates SERRS indirectly by subradiant plasmons, which receive light energy from the superradiant plasmons. This indirect SERRS process clarifies that the interaction between the superradiant and subradiant plasmons results in an identical polarization dependence between SERRS and plasmon resonance for Type II of dimers.Comment: 31 pages, 9 figures. arXiv admin note: substantial text overlap with arXiv:2207.0251

Electromagnetic enhancement of one-dimensional plasmonic hotspots along silver nanowire dimer examined by ultrafast surface enhanced fluorescence

We investigated the spectral properties of electromagnetic (EM) enhancement of one-dimensional hotspots (1D HSs) generated between silver nanowire (NW) dimers. The EM enhancement spectra were directly derived by dividing the spectra of ultrafast surface-enhanced fluorescence (UFSEF) from single NW dimers with UFSEF obtained from large nanoparticle aggregates, which aggregate-by-aggregate variations in the UFSEF spectra were averaged out. Some NW dimers were found to exhibit EM enhancement spectra that deviated from the plasmon resonance Rayleigh scattering spectra, indicating that their EM enhancement was not generated by superradiant plasmons. These experimental results were examined by numerical calculation based on the EM mechanism by varying the morphology of the NW dimers. The calculations reproduced the spectral deviations as the NW diameter dependence of EM enhancement. Phase analysis of the enhanced EM near fields along the 1D HSs revealed that the dipole-quadrupole coupled plasmon, which is a subradiant mode, mainly generates EM enhancement for dimers with NW diameters larger than ~80 nm, which was consistent with scanning electron microscopic measurements.Comment: 46 pages, 10 figure

Spectral correlation between surface-enhanced resonant Raman and far field scattering destructed by dipole quadrupole coupled plasmon resonance

The spectral relationships between surface enhanced resonant Raman scattering (SERRS) and plasmon resonance observed in far field scattering cross are investigated using single silver nanoparticle dimers with focusing on the lowest energy (superradiant) plasmon resonance. We find that these relationships can be classified into two types. The first is SERRS spectral envelopes with spectral shapes similar to those of plasmon resonance spectra. The second is SERRS envelopes exhibiting higher energy shifts from the plasmon resonance spectra. These results are examined as an effect of degree of morphological asymmetry in dimers based on an electromagnetic (EM) mechanism. The analysis of the first and second types reveals that dipole-dipole and dipole-quadrupole coupled plasmon resonance (subradiant Fano resonance) respectively determine the EM enhancement. This mechanism is commonly important for the development of plasmonic nanostructures for various surface enhanced spectroscopies.Comment: 43 pages, 15 figure

Optical properties of a newly developed fiber-optic miniaturized Raman probe and its application to nondestructive biomedical tissue measurement

関西学院大

Direct search for solar axions by using strong magnetic field and X-ray detectors

We have searched for axions which could be produced in the solar core by exploiting their conversion to X rays in a strong laboratory magnetic field. The signature of the solar axion is an increase in the rate of the X rays detected in a magnetic helioscope when the sun is within its acceptance. From the absence of such a signal we set a 95% confidence level limit on the axion coupling to two photons $g_{a\gamma\gamma}\equiv 1/M < 6.0\times 10^{-10}$ GeV$^{-1}$, provided the axion mass $m_a<0.03$ eV. The limit on the coupling is factor 4.5 more stringent than the recent experimental result. This is the first experiment whose sensitivity to $g_{a\gamma\gamma}$ is higher than the limit constrained by the solar age consideration.Comment: 11 pages, REVTeX, 4 eps figures included, submitted to PL