Multicascade-linked synthetic wavelength digital holography using an optical-comb-referenced frequency synthesizer

Digital holography (DH) is a promising method for non-contact surface topography because the reconstructed phase image can visualize the nanometer unevenness in a sample. However, the axial range of this method is limited to the range of the optical wavelength due to the phase wrapping ambiguity. Although the use of two different wavelengths of light and the resulting synthetic wavelength, i.e., synthetic wavelength DH, can expand the axial range up to a few tens of microns, this method is still insufficient for practical applications. In this article, a tunable external cavity laser diode phase-locked to an optical frequency comb, namely, an optical-comb-referenced frequency synthesizer, is effectively used for multiple synthetic wavelengths within the range of 32 um to 1.20 m. A multiple cascade link of the phase images among an optical wavelength (= 1.520 um) and 5 different synthetic wavelengths (= 32.39 um, 99.98 um, 400.0 um, 1003 um, and 4021 um) enables the shape measurement of a reflective millimeter-sized stepped surface with the axial resolution of 34 nm. The axial dynamic range, defined as the ratio of the maximum axial range (= 0.60 m) to the axial resolution (= 34 nm), achieves 1.7*10^8, which is much larger than that of previous synthetic wavelength DH. Such a wide axial dynamic range capability will further expand the application field of DH for large objects with meter dimensions.Comment: 19 pages, 7 figure

Evaluation of acquired color vision deficiency in glaucoma using the Rabin cone contrast test.

To evaluate acquired color vision deficiency in glaucoma by using the Rabin cone contrast test (RCCT).Twenty-seven eyes of 27 patients with glaucoma (glaucoma group) and 27 eyes of 27 normal subjects (control group) were included in this study. Long (L), medium (M), and short (S) CCT scores (L CCTs, M CCTs, and S CCTs, respectively) were measured using the RCCT in both groups. Visual field examinations were performed with Humphrey automated perimetry using the Swedish interactive thresholding algorithm 30-2, and the mean deviation (MD) was evaluated. The macular ganglion cell/inner plexiform layer (GCIPL) thickness was measured using high-definition optical coherence tomography in the glaucoma group.The mean M CCTs and S CCTs in the glaucoma group were significantly lower (P<0.05 for both comparisons) than in the control group (M CCTs, 80.7±16.8 vs. 91.9±8.22; S CCTs, 83.9±19.5 vs. 97.4±3.77, respectively); the L CCTs did not differ significantly (P=0.065) from those of the controls (91.8±12.8 vs. 97.4±3.50, respectively). The M CCTs and S CCTs were correlated significantly with those of MD (M CCTs, r=0.47; S CCTs, r=0.44; P<0.05 for both comparisons) and GCIPL thickness (M CCTs, r=0.70; P<0.0001; S CCTs, r=0.57; P<0.01).The chromatic discrimination thresholds measured by RCCT in the glaucoma group were significantly different from those measured in the control group and were correlated with the MD and GCIPL thickness. The RCCT may be useful for evaluating acquired color vision deficiency in glaucoma and may help advance current understanding of the pathophysiology of glaucomatous damage

Multicascade-linked synthetic wavelength digital holography using an optical-comb-referenced frequency synthesizer

Digital holography (DH) is a promising method for non-contact surface topography because the reconstructed phase image can visualize the nanometer unevenness in a sample. However, the axial range of this method is limited to the range of the optical wavelength due to the phase wrapping ambiguity. Although the use of two different wavelengths of light and the resulting synthetic wavelength, i.e., synthetic wavelength DH, can expand the axial range up to several hundreds of millimeters, its axial precision does not reach sub-micrometer. In this article, we constructed a tunable external cavity laser diode phase-locked to an optical frequency comb, namely, an optical-comb-referenced frequency synthesizer, enabling us to generate multiple synthetic wavelengths within the range of 32 μm to 1.20 m. A multiple cascade link of the phase images among an optical wavelength ( = 1.520 μm) and 5 different synthetic wavelengths ( = 32.39 μm, 99.98 μm, 400.0 μm, 1003 μm, and 4021 μm) enables the shape measurement of a reflective millimeter-sized stepped surface with the axial resolution of 34 nm. The axial dynamic range, defined as the ratio of the axial range ( = 2.0 mm) to the axial resolution ( = 34 nm), achieves 5.9 × 105, which is larger than that of previous synthetic wavelength DH. Such a wide axial dynamic range capability will further expand the application field of DH for large objects with meter dimensions

A review of clinical characteristics and genetic backgrounds in Alport syndrome

Alport syndrome (AS) is a progressive hereditary renal disease that is characterized by sensorineural hearing loss and ocular abnormalities. It is divided into three modes of inheritance, namely, X-linked Alport syndrome (XLAS), autosomal recessive AS (ARAS), and autosomal dominant AS (ADAS). XLAS is caused by pathogenic variants in COL4A5, while ADAS and ARAS are caused by those in COL4A3/COL4A4. Diagnosis is conventionally made pathologically, but recent advances in comprehensive genetic analysis have enabled genetic testing to be performed for the diagnosis of AS as first-line diagnosis. Because of these advances, substantial information about the genetics of AS has been obtained and the genetic background of this disease has been revealed, including genotype–phenotype correlations and mechanisms of onset in some male XLAS cases that lead to milder phenotypes of late-onset end-stage renal disease (ESRD). There is currently no radical therapy for AS and treatment is only performed to delay progression to ESRD using nephron-protective drugs. Angiotensin-converting enzyme inhibitors can remarkably delay the development of ESRD. Recently, some new drugs for this disease have entered clinical trials or been developed in laboratories. In this article, we review the diagnostic strategy, genotype–phenotype correlation, mechanisms of onset of milder phenotypes, and treatment of AS, among others

Decreased orbital fat and enophthalmos due to bimatoprost: Quantitative analysis using magnetic resonance imaging.

We quantitatively determined the relation between the decrease in orbital fat and enophthalmos due to bimatoprost using magnetic resonance imaging (MRI). Nine orbits in nine patients were treated unilaterally with bimatoprost for glaucoma or ocular hypertension. The contralateral orbits were used as controls. The volumes of the orbital tissues and the enophthalmos were measured using MRI. The mean volumes on the treated and untreated sides were, respectively, 14.6 ± 2.1 and 17.0 ± 4.3 cm3 for orbital fat (P = 0.04) and 3.4 ± 0.5 and 3.3 ± 0.5 cm3 for total extraocular muscles (P = 0.85). The mean enophthalmos values were 14.7 ± 2.5 and 16.0 ± 2.3 mm on the treated and untreated sides, respectively (P = 0.002). The data acquired by quantitatively measuring the volumes of orbital fat and enophthalmos on MRI showed that each might be reduced by bimatoprost administration. The enophthalmos could be caused by the bimatoprost-induced decrease in orbital fat

Long-Term Progressive Degradation of the Biological Capability of Titanium

Titanium undergoes time-dependent degradation in biological capability, or “biological aging”. It is unknown whether the biological aging of titanium occurs beyond four weeks and whether age-related changes are definitely associated with surface hydrophilicity. We therefore measured multiple biological parameters of bone marrow-derived osteoblasts cultured on newly prepared, one-month-old, three-month-old, and six-month-old acid-etched titanium surfaces, as well as the hydrophilicity of these surfaces. New surfaces were superhydrophilic with a contact angle of ddH2O of 0°, whereas old surfaces were all hydrophobic with the contact angle of around 90°. Cell attachment, cell spread, cell density, and alkaline phosphatase activity were highest on new surfaces and decreased in a time-dependent manner. These decreases persisted and remained significant for most of the biological parameters up to six-months. While the number of attached cells was negatively correlated with hydrophilicity, the other measured parameters were not. The biological capability of titanium continues to degrade up to six months of aging, but these effects are not directly associated with time-dependent reductions in hydrophilicity. A full understanding of the biological aging will help guide regulatory improvements in implant device manufacturing and develop countermeasures against this phenomenon in order to improve clinical outcomes

Long-Term Progressive Degradation of the Biological Capability of Titanium

Titanium undergoes time-dependent degradation in biological capability, or “biological aging”. It is unknown whether the biological aging of titanium occurs beyond four weeks and whether age-related changes are definitely associated with surface hydrophilicity. We therefore measured multiple biological parameters of bone marrow-derived osteoblasts cultured on newly prepared, one-month-old, three-month-old, and six-month-old acid-etched titanium surfaces, as well as the hydrophilicity of these surfaces. New surfaces were superhydrophilic with a contact angle of ddH2O of 0°, whereas old surfaces were all hydrophobic with the contact angle of around 90°. Cell attachment, cell spread, cell density, and alkaline phosphatase activity were highest on new surfaces and decreased in a time-dependent manner. These decreases persisted and remained significant for most of the biological parameters up to six-months. While the number of attached cells was negatively correlated with hydrophilicity, the other measured parameters were not. The biological capability of titanium continues to degrade up to six months of aging, but these effects are not directly associated with time-dependent reductions in hydrophilicity. A full understanding of the biological aging will help guide regulatory improvements in implant device manufacturing and develop countermeasures against this phenomenon in order to improve clinical outcomes

Spectral Fingerprinting of Individual Cells Visualized by Cavity-Reflection-Enhanced Light-Absorption Microscopy

<div><p>The absorption spectrum of light is known to be a “molecular fingerprint” that enables analysis of the molecular type and its amount. It would be useful to measure the absorption spectrum in single cell in order to investigate the cellular status. However, cells are too thin for their absorption spectrum to be measured. In this study, we developed an optical-cavity-enhanced absorption spectroscopic microscopy method for two-dimensional absorption imaging. The light absorption is enhanced by an optical cavity system, which allows the detection of the absorption spectrum with samples having an optical path length as small as 10 μm, at a subcellular spatial resolution. Principal component analysis of various types of cultured mammalian cells indicates absorption-based cellular diversity. Interestingly, this diversity is observed among not only different species but also identical cell types. Furthermore, this microscopy technique allows us to observe frozen sections of tissue samples without any staining and is capable of label-free biopsy. Thus, our microscopy method opens the door for imaging the absorption spectra of biological samples and thereby detecting the individuality of cells.</p></div

Observation of human rectal tumor model and mouse normal rectal tissues.

<p>(A) Hematoxylin-Eosin stained mouse normal rectal tissues (left) and human rectal tumor model (right). Scale bar represents 0.5 mm. (B) Cavity-reflection enhanced absorption images of mouse normal rectal tissues (left) and human rectal tumor model (right). Scale bar represents 100 μm. Pseudo-colored images were constructed by merging the 3 colors as follows: blue for 450 to 500 nm, green for 500 to 550 nm, and red for 550 to 600 nm of averaged images. (C) Cavity-reflection-enhanced absorption spectrum of mouse normal rectal tissues (black) and human rectal tumor model (red).</p