155 research outputs found
Application of Fmoc-amino acid carrying an unmasked carbohydrate to the synthesis of the epidermal growth factor-like domain of bovine blood coagulation factor IX
Photonic-Crystal-Fiber-Coupled, Hand-Held, Polarization-Resolved Second-Harmonic-Generation Microscope for In Vivo Visualization of Dermal Collagen Fibers in Human Skin
Second-harmonic-generation (SHG) microscopy is a powerful tool for in vivo monitoring of collagen fibers in human skin. Furthermore, polarization-resolved SHG microscopy can provide additional insights regarding the direction of collagen fibers, i.e., collagen fiber orientation. However, their practical use in the dermatological field is still limited due to the bulky and complicated setup. In this paper, we constructed a photonic-crystal-fiber-coupled, hand-held polarization-resolved SHG microscope for in vivo monitoring of collagen fibers in human skin. Fiber delivery of ultrashort pulse light was achieved without significant change of the linear polarization by a large-mode-area photonic-crystal-fiber whereas the SHG microscopy setup was enclosed into a hand-held probe head. The combination of PCF with the hand-held probe head largely enhances the flexibility of measurement sites in the human skin
Nanometer-precision surface metrology of millimeter-size stepped objects using full-cascade-linked synthetic-wavelength digital holography using a line-by-line full-mode-extracted optical frequency comb
Digital holography (DH) is a powerful tool for surface profilometry of
objects with sub-wavelength precision. In this article, we demonstrate
full-cascade-linked synthetic-wavelength DH (FCL-SW-DH) for nanometer-precision
surface metrology of millimeter-size stepped objects. 300 modes of optical
frequency comb (OFC) with different wavelengths are sequentially extracted at a
step of mode spacing from a 10GHz-spacing, 3.72THz-spanning electro-optic
modulator OFC (EOM-OFC). The resulting 299 synthetic wavelengths and a single
optical wavelength are used to generate a fine-step wide-range cascade link
covering within a wavelength range of 1.54 um to 29.7 mm. We determine the
0.1000mm-stepped surface with axial uncertainty of 6.1 nm within the maximum
axial range of 14.85 mm.Comment: 22 pages, 6 figure
Evaluation of the histological and mechanical features of tendon healing in a rabbit model
Objectives
This study aimed to evaluate the histological and mechanical features of tendon healing in a rabbit model with second-harmonic-generation (SHG) imaging and tensile testing.
Materials and Methods
A total of eight male Japanese white rabbits were used for this study. The flexor digitorum tendons in their right leg were sharply transected, and then were repaired by intratendinous stitching. At four weeks post-operatively, the rabbits were killed and the flexor digitorum tendons in both right and left legs were excised and used as specimens for tendon healing (n = 8) and control (n = 8), respectively. Each specimen was examined by SHG imaging, followed by tensile testing, and the results of the two testing modalities were assessed for correlation.
Results
While the SHG light intensity of the healing tendon samples was significantly lower than that of the uninjured tendon samples, 2D Fourier transform SHG images showed a clear difference in collagen fibre structure between the uninjured and the healing samples, and among the healing samples. The mean intensity of the SHG image showed a moderate correlation (R2 = 0.37) with Young’s modulus obtained from the tensile testing.
Conclusion
Our results indicate that SHG microscopy may be a potential indicator of tendon healing
Application of Scan-less Two-Dimensional Confocal Microscopy Based on a Combination of Confocal Slit With Wavelength/Space Conversion
Confocal laser microscope (CLM) has been widely used in the fields of the non-contact surface topography, biomedical imaging, and other applications, because the confocality gives two-dimensional (2D) optical-sectioning or three-dimensional (3D) imaging capability with the depth selectivity. Combination of line-focused CLM with one-dimensional (1D) spectral encoding CLM enables us to obtain the 2D confocal image without the need for the mechanical scanning. So-called scan-less 2D CLM is a unique imaging modality, however, there are no attempts to apply for practical application. In this paper, we constructed scan-less 2D CLM with the image acquisition time of 0.23 ms, the lateral resolution of 1.2 µm, the depth resolution of 2.4 µm, and apply it for different kinds of application to evaluate its practical potential
Scan-less full-field fluorescence-lifetime dual-comb microscopy using two-dimensional spectral mapping and frequency multiplexing of dual-optical-comb beats
Fluorescence lifetime imaging microscopy (FLIM) is a powerful tool for
quantitative fluorescence imaging because fluorescence lifetime is independent
of concentration of fluorescent molecules or excitation/detection efficiency
and is robust to photobleaching. However, since FLIM is based on point-to-point
measurements, mechanical scanning of a focal spot is needed for forming an
image, which hampers rapid imaging. In this article, we demonstrate scan-less
full-field FLIM based on a one-to-one correspondence between two-dimensional
(2D) image pixels and frequency-multiplexed RF signals. A vast number of
dual-optical-comb beats between dual optical frequency combs is effectively
adopted for 2D spectral mapping and high-density frequency multiplexing in
radio-frequency region. Bimodal images of fluorescence amplitude and lifetime
are obtained with high quantitativeness from amplitude and phase spectra of
fluorescence RF comb modes without the need for mechanical scanning. The
proposed method will be useful for rapid quantitative fluorescence imaging in
life science.Comment: 38 pages, 8 figures, 1 tabl
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