ジコ シンダン ノ タメ ノ キンセキガイ ブンコウ ガゾウ ケイソク プローブ ノ カイハツ

We develop a multi-channel probe system and a scanning probe system for a near-infrared spectroscopy imaging. The multi-channel probe system is composed of one light source module and eight photodetector modules. To obtain a photon path from the light source to the detector using the multi-channel probe system, we utilize a phantom containing a movable absorber in a liquid light scattering medium. The scanning probe system is composed of a nearinfrared light source, a detector, and a light source indicating a position. The probe position is detected by a camera. We realize an isotropic spatial response by use of an improved probe containing two source-and-detector pairs in a cross arrangement

Improvement of dynamic range and repeatability in refractive-index-sensing optical comb by combination of saturable-absorber-mirror mode-locking with intracavity multi-mode interference fiber sensor

Mode-locked fiber comb equipped with multi-mode-interference fiber sensor functions as high-precision refractive-index (RI) sensor benefitting from precise radio-frequency measurement. However, its dynamic range and repeatability are hampered by inherent characteristics in nonlinear-polarization-rotation mode-locking oscillation. In this article, we introduce saturable-absorber-mirror mode-locking for RI sensing with wide dynamic range and high repeatability. While the RI dynamic range was expanded to 41.4 dB due to high robustness to cavity disturbance, self-starting capability without the need for polarization control improves the RI sensing repeatability to 1.10×10-8 every mode-locking activation. Improved dynamic range and repeatability will be useful for enhanced performance of RI sensing

Refractive index sensing with temperature compensation by a multimode-interference fiber-based optical frequency comb sensing cavity

We proposed a refractive index (RI) sensing method with temperature compensation by using an optical frequency comb (OFC) sensing cavity including a multimode-interference (MMI) fiber, namely, the MMI-OFC sensing cavity. The MMI-OFC sensing cavity enables simultaneous measurement of material-dependent RI and sample temperature by decoding from the comb spacing frequency shift and the wavelength shift of the OFC. We realized the simultaneous and continuous measurement of RI-related concentration of a liquid sample and its temperature with precisions of 1.6 × 10−4 RIU and 0.08 °C. The proposed method would be a useful means for the various applications based on RI sensing

Refractive-index-sensing optical comb based on photonic radio-frequency conversion with intracavity multi-mode interference fiber sensor

Optical frequency combs (OFCs) have attracted attention as optical frequency rulers due to their tooth-like discrete spectra together with their inherent mode-locking nature and phase-locking control to a frequency standard. Based on this concept, their applications until now have been demonstrated in the fields of optical frequency metrology. However, if the utility of OFCs can be further expanded beyond their application by exploiting new aspects of OFCs, this will lead to new developments in optical metrology and instrumentation. Here, we report a fiber sensing application of OFCs based on a coherent link between the optical and radio frequencies, enabling high-precision refractive index measurement based on frequency measurement in radio-frequency (RF) region. Our technique encodes a refractive index change of a liquid sample into a repetition frequency of OFC by a combination of an intracavity multi-mode-interference fiber sensor and wavelength dispersion of a cavity fiber. Then, the change in refractive index is read out by measuring the repetition frequency in RF region based on a frequency standard. Use of an OFC as a photonic RF converter will lead to the development of new applications in high-precision fiber sensing with the help of functional fiber sensors and precise RF measurement

Prognostic significance of serum hepatocyte growth factor in clear cell renal cell carcinoma : comparison with serum vascular endothelial growth factor

No adequate serum predictive biomarker currently exists, which can identify the activity of renal cell carcinoma (RCC). We investigate the association of serum hepatocyte growth factor (HGF) and serum vascular endothelial growth factor (VEGF) levels with clinicopathologic parameters in untreated clear cell RCC patients. We measured serum levels of HGF and VEGF in 45 patients with untreated clear cell RCC and 45 healthy controls using an enzyme-linked immunosorbent assay (ELISA). Patients with clear cell RCC had significantly higher serum HGF and VEGF concentrations than healthy subjects : median, 1070.7 versus 728.3 pg/ml (p1150 pg/ml) was significantly reduced compared to patients with low serum HGF concentrations (p=0.0044). In patients with nuclear grade 2 or high stage RCC, the higher serum HGF group exhibited significantly lower cause-specific survival (p= 0.0087 and p<0.05, respectively). No significant difference was observed between serum VEGF levels and cause-specific survival rate. Serum HGF might be a diagnostic and prognostic indicator in clear cell RCC, especially for patients with grade 2 or high stage RCC

AC susceptibility measurement of magnetic nanoparticles using an optically pumped magnetometer and a flux transformer

Magnetic particle imaging (MPI) is used to detect small magnetic fields in magnetic nanoparticles (MNPs). As a first step in MPI systems, we proposed an AC susceptibility measurement system with an optically pumped magnetometer (OPM) based on a flux transformer. First, the magnetic frequency response of the OPM was obtained for calibration. Second, the AC susceptibility of the Resovist MNPs in liquid and solid phases was obtained using the calibration data. These results are consistent with those of previous studies. Therefore, the proposed method is useful for detecting weak MNP magnetic signals in relatively strong magnetic fields and is expected to be applicable to MPI

Rapid, high-sensitivity detection of biomolecules using dual-comb biosensing

Abstract Rapid, sensitive detection of biomolecules is important for biosensing of infectious pathogens as well as biomarkers and pollutants. For example, biosensing of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is still strongly required for the fight against coronavirus disease 2019 (COVID-19) pandemic. Here, we aim to achieve the rapid and sensitive detection of SARS-CoV-2 nucleocapsid protein antigen by enhancing the performance of optical biosensing based on optical frequency combs (OFC). The virus-concentration-dependent optical spectrum shift produced by antigen–antibody interactions is transformed into a photonic radio-frequency (RF) shift by a frequency conversion between the optical and RF regions in the OFC, facilitating rapid and sensitive detection with well-established electrical frequency measurements. Furthermore, active-dummy temperature-drift compensation with a dual-comb configuration enables the very small change in the virus-concentration-dependent signal to be extracted from the large, variable background signal caused by temperature disturbance. The achieved performance of dual-comb biosensing will greatly enhance the applicability of biosensors to viruses, biomarkers, environmental hormones, and so on