Mid-infrared passive spectroscopic imaging for visualizing tooth quality.

Although the measurement of tooth quality is necessary for precise prediction of caries formation, typical measurement methods include tooth-hardness measurements and absorption spectroscopy, which generally use infrared light irradiation. These methods are destructive or invasive, and obtaining two-dimensional information in the oral cavity is difficult. Mid-infrared emissions from the surface of an object reflect intrinsic vibrations of molecules in the object.

Glucose emission spectra through mid-infrared passive spectroscopic imaging of the wrist for non-invasive glucose sensing.

Non-invasive blood glucose sensing can be achieved using mid-infrared spectroscopy, although no practical device based on this method has yet been developed. Here, we propose mid-infrared passive spectroscopic imaging for glucose measurements from a distance. Spectroscopic imaging of thermal radiation from the human body enabled, for the first time in the world, the detection of glucose-induced luminescence from a distance.

Identification of black microplastics using long-wavelength infrared hyperspectral imaging with imaging-type two-dimensional Fourier spectroscopy.

Despite recent progress in focal plane array Fourier transform infrared spectroscopy (FPA-FT-IR) for automatic microplastic (MP) discrimination, the analysis time is still too long (e.g., 9 h for a sample with a diameter of 47 mm) and the equipment is expensive.

Parametric standing wave generation of a shallow reflection plane in a nonrigid sample for use in a noninvasive blood glucose monitor.

When monitoring a moist sample using mid-infrared spectroscopy, its thickness must be <100  μm to avoid light absorption from the water. Therefore, we propose an ultrasonic-assisted mid-infrared spectroscopic imaging method that can generate a reflection plane at a depth of 100  μm from the surface of the sample by creating an ultrasonic standing wave. A frequency of 10 MHz is required to obtain an optical path length of 100  μm in biological samples.

Ultrasonic standing wave preparation of a liquid cell for glucose measurements in urine by midinfrared spectroscopy and potential application to smart toilets.

Smart toilets could be used to monitor different components of urine in daily life for early detection of lifestyle-related diseases and prompt provision of treatment. For analysis of biological samples such as urine by midinfrared spectroscopy, thin-film samples like liquid cells are needed because of the strong absorption of midinfrared light by water. Conventional liquid cells or fixed cells are prepared based on the liquid membrane method and solution technique, but these are not quantitative and are difficult to set up and clean.

Nonstaining Blood Flow Imaging Using Optical Interference Due to Doppler Shift and Near-Infrared Imaging of Molecular Distribution in Developing Fish Egg Embryos.

In the present study, we successfully obtained nonstaining blood flow images of a developing fish egg embryo using optical interference caused by the Doppler shift. The spectral distribution of light reflected by moving objects such as the heart and red cells was found to be different from that of the incident light because of the Doppler effect. Interference between different frequency components was observed in an interferogram through heterodyne interaction using an imaging-type two-dimensional Fourier spectroscopic system, and information on the intensities of the spectral components was obtained by Fourier transformation.

Wide-field mid-infrared hyperspectral imaging of adhesives using a bolometer camera.

By combining a bolometer detector with an imaging-type interferometer, an inexpensive, easy-to-handle wide-field mid-infrared hyperspectral imaging apparatus was produced. We measured the distributions of four types of thin adhesive layers on an aluminium plate and analysed the results using correlation coefficients to visualise the distribution of various adhesives that cannot be discerned by the naked eye or conventional methods such as visible/near-infrared spectroscopic/fluorescent photography. The measurement wavelength range, obtained spectrum's wavenumber resolution, and measurement time was 8-14 μm, about 9 cm, and about 30 s, respectively.

Enhanced interference-pattern visibility using multislit optical superposition method for imaging-type two-dimensional Fourier spectroscopy.

A solution is found for the problem of phase cancellation between adjacent bright points in wavefront-division phase-shift interferometry. To this end, a design is proposed that optimizes the visibility of the interference pattern from multiple slits. The method is explained in terms of Fraunhofer diffraction and convolution imaging.

Use of protein array to investigate receptor tyrosine kinases activated in gastric cancer.

Our study used protein array technology to analyze the expression status of various activated receptor tyrosine kinases (RTKs) in gastric carcinoma; then, we sought to discover an effective therapeutic receptor tyrosine kinase for this disease and investigated the anti-tumor mechanism of the therapeutic RTK. In addition to the expressions of activated RTKs in human gastric cancer and adjacent normal mucosa, the expression of activated RTKs in gastric cancer cell lines, MKN74, MKN45, MKN7 and MKN1, were also studied. The RTKs activated in gastric cancer tissue are EGFR, ErbB2, FGFR1, FGFR2alpha insulin R, and EphA4.