A Fabry-Perot Sensor with Cascaded Polymer Films Based on Vernier Effect for Simultaneous Measurement of Relative Humidity and Temperature.

In this paper, fiber sensor based on Vernier effect for simultaneous measurement of relative humidity (RH) and temperature is proposed. The sensor is fabricated by coating two kinds of ultraviolet (UV) glue with different refractive indexes (RI) and thicknesses on the end face of a fiber patch cord. The thicknesses of two films are controlled to generate the Vernier effect. The inner film is formed by a cured lower-RI UV glue. The exterior film is formed by a cured higher-RI UV glue, of which thickness is much thinner than the inner film. Through the analysis of the Fast Fourier Transform (FFT) of the reflective spectrum, the Vernier effect is formed by the inner lower-RI polymer cavity and the cavity composed of both polymer films. By calibrating the RH and temperature response of two peaks on the envelope of the reflection spectrum, simultaneous measurements of RH and temperature are realized by solving a set of quadratic equations. Experimental results show that the highest RH and temperature sensitivities of the sensor are 387.3 pm/%RH (in 20%RH to 90%RH) and -533.0 pm/°C (in 15 °C to 40 °C), respectively. The sensor has merits of low cost, simple fabrication, and high sensitivity, which makes it very attractive for applications that need to simultaneously monitor these two parameters.

Temperature compensation of optical alternating magnetic field sensor via a novel method for on-line measuring.

The variation of environment temperature is a crucial problem for optical magnetic field sensors based on the magneto-optical crystal. In this paper, we propose a novel temperature compensation method for optical alternating magnetic field measuring by analyzing the demodulation principle and establishing the temperature compensation model, which can implement the functions of temperature compensation and on-line measuring simultaneously. Both the temperature and the alternating magnetic field flux density can be obtained only by adding two magnet rings on the magnetic field sensor. The experimental phenomenon agrees well with the temperature characteristics of the magneto-optical crystal and the theoretical compensation model. The experimental results demonstrate that this sensor has excellent stability whose max relative fluctuation is only 0.7402% in the range of 0-4 mT under a constant temperature. In the temperature compensation experiment of 0 °C, 20 °C and 40 °C, the sensor shows strong temperature robustness that the max absolute and relative errors are 0.07 mT and 3.50%, respectively. Meanwhile, compensation efficiency reaches 83.968%, which can effectively avoid temperature crosstalk to a large extent. Additionally, it has a better compensation performance whose max absolute and relative errors are 0.15 mT and 1.66% in the broader range of 0-16 mT when the actual temperature is accurately known.

[Real-time cell analysis combined with pattern recognition to evaluate anaphylaxis of Zushima Injection].

This paper was aimed to establish a new method for evaluating the anaphylactoid reaction of 15 batches of Zushima Injection from different manufacturers in vitro. Basophilic leukemia cell line RBL-2 H3 cells were cultured in vitro and Compound 48/80 was selected as positive drug. Real-time cell analysis(RTCA) system was used to detect the changes of cell index(CI) value after drug intervention. The degranulation of RBL-2 H3 cells was verified with the toluidine blue staining technology by observing the changes of cell morphology and skeleton. Clustering method was used to analyze the CI values of 15 batches of Zushima Injection on RBL-2 H3 cells. The results showed Compound 48/80(20 µg·mL~(-1)) significantly changed the cell morphology and cytoskeleton, with obvious degranulation. After adding Compound 48/80, CI value decreased rapidly within 30 minutes, then decreased slowly, suggesting that RTCA system can be used for rapid and sensitive evaluation of RBL-2 H3 cell degranulation. The results of cluster analysis showed that Zushima Injection from different manufacturers had different effects on RBL-2 H3 cells. S1-S8 and Compound 48/80 groups were grouped into one cluster, which suggesting that the sample might have potential clinical anaphylaxis. S9-S15 and the normal control group were grouped into one cluster, suggesting there was no anaphylactoid reaction in the sample. In this study, a rapid in vitro anaphylaxis evaluation technique based on RTCA system and pattern recognition method was established, which can be used for rapid in vitro evaluation of anaphylaxis for traditional Chinese medicine injection.

Contrast optimization in broadband passive polarimetric imaging based on color camera.

Broadband polarimetric imaging consists of forming an image under spectrally wide illumination after having optimized the polarization state analyzer (PSA) to maximize the target/background discriminability. In previous works, the image sensor was monochrome, and only the intensity contrast was optimized. However, due to its spectrally varying response, the PSA not only changes the light's intensity, but also its color. This color information can serve as a further parameter to improve discrimination. In this paper, we employ a color camera in a broadband Stokes (passive) polarimetric imaging system and take into color difference's contribution to discrimination ability in optimizing the PSA setting. We show through experiments that a significant improvement of discrimination ability over monochrome imaging is obtained, especially when there are multiple objects in the scene.

Optimal design of high-power cascade co-pumping Er/Yb-codoped fiber lasers.

The Yb-ASE problem has been a main obstacle to the power scaling of Er/Yb-codoped fiber lasers (EYDFLs). In this Letter, cascade co-pumping high-power EYDFLs, i.e., EYDFLs with an Yb-band resonant cavity, are proposed and systematically analyzed, for the first time to the best of our knowledge. A high-Q Yb-band cavity is introduced in an EYDFL to lock and recycle the Yb band energy. The oscillation wavelength of the Yb cavity, the reflectivity of the output fiber grating, and the length of the fiber are optimized numerically. Thermal effects are also considered in the study. The simulation results show that compared to ordinary EYDFLs, the introduction of an appropriate Yb cavity can not only effectively suppress the Yb-ASE, increase the output power, and improve the pump conversion efficiency, but can also greatly shorten the optimal gain fiber length. Cascade co-pumping is a promising way to improve the performance of high-power EYDFLs.

MHC class I diversity predicts non-random mating in Chinese alligators (Alligator sinensis).

The major histocompatibility complex (MHC) has several important roles in kin recognition, pathogen resistance and mate selection. Research in fish, birds and mammals has suggested that individuals optimise MHC diversity, and therefore offspring fitness, when choosing mates. In reptiles, however, it is unclear whether female mate choice is based on genome-wide genetic characteristics such as microsatellite DNA loci, particular functional-trait loci (e.g., MHC) or both, and MHC's effects on mate choice remain relatively understudied. Herein, we used 13 microsatellite loci and two MHC class I loci to investigate female mate choice of Chinese alligators (Alligator sinensis) in the semi-natural condition. We also determined correlations between the MHC genotype of breeding males and male reproductive success. We found that MHC-heterozygous males harbour a greater reproductive success, which probably is the reason that these males are more preferred by the females than MHC-homozygous males. Furthermore, the MHC class I amino-acid distance and functional distance of true mating pairs were higher compared with those of randomly sampled pairs. Analysis of microsatellites revealed that, despite mate choice, females did not completely avoid inbreeding. These findings are the first evidence of MHC-associated mate choice in Chinese alligators, suggesting that females may adopt different mating strategies after assessing the MHC characteristics of potential mates.

Initial exploration of coronary stent image subtraction using dual-layer spectral CT.

OBJECTIVES: This study aimed to investigate the feasibility of coronary stent image subtraction using spectral tools derived from dual-layer spectral computed tomography (CT). METHODS: Forty-three patients (65 stents) who underwent coronary CT angiography using dual-layer spectral CT were included. Conventional, 50-keV (kilo electron-volt), 100-keV, and virtual non-contrast (VNC) images were reconstructed from the same cardiac phase. Stents were subtracted on VNC images from conventional (convsub), 100-keV (100-keVsub), and 50-keV (50-keVsub) images. The in-stent lumen diameters were measured on subtraction, conventional, and 100-keV images. Subjective evaluation of reader confidence and subtractive quality was evaluated. Friedman tests were performed to compare in-stent lumen diameters and subjective evaluation among different images. Correlation between stent diameter and subjective evaluation was expressed as Spearman's rank correlation coefficient (rs). The diagnostic accuracy was assessed according to invasive coronary angiography (ICA) performed in 11 patients (20 stents). RESULTS: In-stent lumen diameters were significantly larger on subtraction images than those on conventional and 100-keV images (p < 0.05). Higher reader confidence was found on 100-keV, convsub, 100-keVsub, and 50-keVsub images compared with conventional images (p < 0.05). Subtractive quality of 100-keVsub images was better than that of convsub images (p = 0.037). A moderate-to-strong correlation between stent diameter and subjective evaluation was found (rs = 0.527~0.790, p < 0.05). Higher specificity, positive predictive value, and negative predictive value of subtraction images were shown by ICA results. CONCLUSIONS: Subtraction images derived from dual-layer spectral CT enhanced in-stent lumen visibility and could potentially improve diagnostic performance for evaluating coronary stents. KEY POINTS: • Dual-layer spectral CT enabled good subtractive quality of coronary stents without misregistration artifacts. • Subtraction images could improve in-stent lumen visibility. • Reader confidence and diagnostic performance were enhanced with subtraction images.

Optimal ellipsometric parameter measurement strategies based on four intensity measurements in presence of additive Gaussian and Poisson noise.

The two ellipsometric parameters of an isotropic sample can be measured with simplified polarimetry setups that acquire at least four intensity measurements. However, these measurements are perturbed by noise and the measurement strategy has to be optimized, in order to limit noise propagation. We determine two different measurement strategies that are optimal for both white Gaussian additive noise and Poisson shot noise. The first one involves a polarization state generator (PSG) with a single state of polarization and a polarization state analyzer (PSA) with four states. The second one involves both PSG and PSA having two states. The total estimation variances obtained with both strategies are demonstrated to be minimal, of equal values, and independent of the ellipsometric parameters to be measured. They are based on simple optical elements and could simplify and accelerate ellipsometric measurements.

Numerical investigation of the thermal effect on Yb-cavity-copumped Er/Yb codoped fiber amplifiers.

Thermal effects are critical constraints for developing high-power Er/Yb-codoped fiber amplifiers (EYDFAs), especially those with an auxiliary Yb-band cavity. In this paper, we developed a numerical model to investigate the temperature-dependent effects on EYDFAs with an Yb-band cavity with consideration of thermal-induced cross-section changes. Our results show that the quantum-defect-induced heat affects the performance of the EYDFA, and its effect varies with the resonant wavelength of the Yb-band cavity. There is a finite applicable resonant wavelength range limited by thermal damage. So, it is important to take into account the thermal effect during the design of such EYDFAs in order to optimize their performance and determine the heat dissipation systems.

Method for estimating the Stark splitting of rare-earth ions from the measured cross-section spectra.

A method to estimate the Stark levels of the rare-earth ions doped in a laser medium from the measured emission and absorption cross-sections is proposed. The method is based on the McCumber theory, which can calculate the emission/absorption cross-sections from the given Stark levels. By fitting the calculated emission/absorption spectra to the measured ones through a numerical optimization process, the Stark levels of the RE ions can be determined. As examples, the Stark levels of the laser-emission-related manifolds of Er3+ and Yb3+ ions in a gain fiber and two doped glasses have been determined by the proposed method. The data were then used to analyze the temperature-dependent population of the Stark levels. This method avoids the difficulties in direct measurement of the Stark levels in a cryogenic temperature environment. It is important to the evaluation of the thermal load, distribution, and design of the thermal management system of high-power fiber lasers and amplifiers.

Sensor based on macrobent fiber Bragg grating structure for simultaneous measurement of refractive index and temperature.

A novel and compact all-fiber sensor based on a macrobent fiber Bragg grating (FBG) structure for simultaneous measurement of refractive index (RI) and temperature is proposed and experimentally investigated. The sensor can be easily fabricated by properly bending an FBG. The bending causes interference between the core mode and the whispering gallery mode, which induces another kind of dip in the transmission spectra of the sensor besides the sharp one of the FBG. Because the two kinds of dips respond differently to the surrounding RI and temperature, these two parameters can be unambiguously measured by the sensor. A sample sensor was fabricated and experimentally investigated, and RI sensitivity of 165.9276 nm/RIU in the range from 1.3330 to 1.3785 and temperature sensitivity of 31.7 pm/°C were achieved. This sensor provides a convenient and economical way for applications where temperature and RI have to be simultaneously measured.

Highly efficient Er/Yb-codoped fiber amplifier with an Yb-band fiber Bragg grating.

In this Letter, a high-power Er/Yb-codoped fiber amplifier (EYDFA) with a high-reflection Yb-band fiber Bragg grating (FBG) at the pump end is experimentally investigated. The FBG was inscribed on a piece of double-clad fiber with a center wavelength of 1032 nm. Due to the selective reflection of the backward Yb-band amplified spontaneous emission (Yb ASE) by the FBG, a co-pump-propagating Yb-band auxiliary signal was generated. Because of the stimulated amplification and reabsorption of the auxiliary signal, the Yb ASE was dramatically suppressed and the pump conversion efficiency (PCE) of the EYDFA was notably improved. An output power of 6.48 W was achieved at a pump power of 16.5 W, which is equivalent to a PCE of ∼39%. The slope efficiency relative to applied pump power was ∼40%. The maximum output power was improved ∼20% because of the introduction of the FBG.

Sphingobium sp. SJ10-10 encodes a not-yet-reported chromate reductase and the classical Rieske dioxygenases to simultaneously degrade PAH and reduce chromate.

Both polycyclic aromatic hydrocarbons (PAHs) and heavy metals persist in the environment and are toxic to organisms. Their co-occurrence makes any of them difficult to remove during bioremediation and poses challenges to environmental management and public health. Microorganisms capable of effectively degrading PAHs and detoxifying heavy metals concurrently are required to improve the bioremediation process. In this study, we isolated a new strain, Sphingobium sp. SJ10-10, from an abandoned coking plant and demonstrated its capability to simultaneously degrade 92.6 % of 75 mg/L phenanthrene and reduce 90 % of 3.5 mg/L hexavalent chromium [Cr(VI)] within 1.5 days. Strain SJ10-10 encodes Rieske non-heme iron ring-hydroxylating oxygenases (RHOs) to initiate PAH degradation. Additionally, a not-yet-reported protein referred to as Sphingobium chromate reductase (SchR), with low sequence identity to known chromate reductases, was identified to reduce Cr(VI). SchR is distributed across different genera and can be classified into two classes: one from Sphingobium members and the other from non-Sphingobium species. The widespread presence of SchR in those RHO-containing Sphingobium members suggests that they are excellent candidates for bioremediation. In summary, our study demonstrates the simultaneous removal of PAHs and Cr(VI) by strain SJ10-10 and provides valuable insights into microbial strategies for managing complex pollutant mixtures.

Optical fiber magnetic field sensor based on single-mode-multimode-single-mode structure and magnetic fluid.

An optical fiber magnetic field sensor based on the single-mode-multimode-single-mode (SMS) structure and magnetic fluid (MF) is proposed and demonstrated. By using a piece of no-core fiber as the multimode waveguide in the SMS structure and MF sealed in a capillary tube as the magnetic sensitive media, which totally immersing the no-core fiber, an all-fiber magnetic sensor was fabricated. Interrogation of the magnetic field strength can be achieved either by measuring the dip wavelength shift of the transmission spectrum or by detecting the transmission loss at a specific wavelength. A demonstration sensor with sensitivities up to 905 pm/mT and 0.748 dB/mT was fabricated and investigated. A theoretical model for the design of the proposed device was developed and numerical simulations were performed.

Wogonin Restrains the Malignant Progression of Lung Cancer Through Modulating MMP1 and PI3K/AKT Signaling Pathway.

BACKGROUND: Wogonin, a natural flavonoid compound, represses cancer cell growth and induces cancer cell apoptosis in diverse malignancies. However, the function of Wogonin in lung cancer cells and its regulatory mechanism deserve to be identified. METHODS: A549 and H460 cells were treated with Wogonin, and the cell growth, apoptosis, migration and invasion were measured by CCK-8 and EdU, flow cytometry and Transwell assays. The targeted genes of Wogonin and lung cancer were identified from the TCMSP and Genecards databases, respectively. The STRING database and Cytoscape software were used to establish a PPI network and screen hub genes. GO and KEGG analysis was conducted to explore the functions and signal pathways related to the hub genes. MMP1 expression in lung cancer was analyzed using the UALCAN databases, and GSEA was performed utilizing LinkedOmics. Gelatin zymography assay was used to detect MMP1 activity. MMP1 mRNA expression was detected by qRT-PCR. Besides, MMP1, p-AKT and c-Myc protein were detected by Western Blot assay. RESULTS: Wogonin could suppress the proliferation, migration and invasion of A549 and H460 cells and induce apoptosis. GO and KEGG enrichment analysis revealed the hub genes were mostly enriched in re-entry into the mitotic cell cycle and apoptosis. The expression of MMP1 was markedly upregulated in lung squamous cell carcinoma, lung adenocarcinoma tissues, and lung cancer cell lines. Wogonin could significantly inhibit MMP1 expression and activity, and overexpression of MMP1 significantly reversed the effect of Wogonin on the malignant phenotypes of A549 and H460 cells. Wogonin inhibited the expression of p-AKT and c-Myc protein by regulating MMP1. CONCLUSION: Wogonin can repress lung cancer cells' growth and metastatic potential and promote cell apoptosis via repressing MMP1 expression and modulating PI3K/AKT signaling pathway.

Flagellar brake protein YcgR interacts with motor proteins MotA and FliG to regulate the flagellar rotation speed and direction.

In E. coli and related species, flagellar brake protein YcgR responds to the elevated intracellular c-di-GMP, decreases the flagellar rotation speed, causes a CCW rotation bias, and regulates bacterial swimming. Boehm et al. suggested that c-di-GMP-activated YcgR directly interacted with the motor protein MotA to curb flagellar motor output. Paul et al. proposed that YcgR disrupted the organization of the FliG C-terminal domain to bias the flagellar rotation. The target proteins are controversial, and the role of motor proteins remains unclear in flagellar rotation speed and direction regulation by YcgR. Here we assayed the motor proteins' affinity via a modified FRET biosensor and accessed the role of those key residue via bead assays. We found that YcgR could interact with both MotA and FliG, and the affinities could be enhanced upon c-di-GMP binding. Furthermore, residue D54 of YcgR-N was needed for FliG binding. The mutation of the FliG binding residue D54 or the MotA binding ones, F117 and E232, restored flagellar rotation speed in wild-type cells and cells lacking chemotaxis response regulator CheY that switched the flagellar rotation direction and decreased the CCW ratio in wild-type cells. We propose that c-di-GMP-activated YcgR regulated the flagellar rotation speed and direction via its interaction with motor proteins MotA and FliG. Our work suggest the role of YcgR-motor proteins interaction in bacterial swimming regulation.

Ultra-low-dose spectral-detector computed tomography for the accurate quantification of pulmonary nodules: an anthropomorphic chest phantom study.

PURPOSE: To assess the quantification accuracy of pulmonary nodules using virtual monoenergetic images (VMIs) derived from spectral-detector computed tomography (CT) under an ultra-low-dose scan protocol. METHODS: A chest phantom consisting of 12 pulmonary nodules was scanned using spectral-detector CT at 100 kVp/10 mAs, 100 kVp/20 mAs, 120 kVp/10 mAs, and 120 kVp/30 mAs. Each scanning protocol was repeated three times. Each CT scan was reconstructed utilizing filtered back projection, hybrid iterative reconstruction, iterative model reconstruction (IMR), and VMIs of 40-100 keV. The signal-to-noise ratio and air noise of images, absolute differences, and absolute percentage measurement errors (APEs) of the diameter, density, and volume of the four scan protocols and ten reconstruction images were compared. RESULTS: With each fixed reconstruction image, the four scanning protocols exhibited no significant differences in APEs for diameter and density (all P > 0.05). Of the four scan protocols and ten reconstruction images, APEs for nodule volume had no significant differences (all P > 0.05). At 100 kVp/10 mAs, APEs for density using IMR were the lowest (APE-mean: 6.69), but no significant difference was detected between VMIs at 50 keV (APE-mean: 11.69) and IMR (P = 0.666). In the subgroup analysis, at 100 kVp/10 mAs, there were no significant differences between VMIs at 50 keV and IMR in diameter and density (all P > 0.05). The radiation dose at 100 kVp/10 mAs was reduced by 77.8% compared with that at 120 kVp/30 mAs. CONCLUSION: Compared with IMR, reconstruction at 100 kVp/10 mAs and 50 keV provides a more accurate quantification of pulmonary nodules, and the radiation dose is reduced by 77.8% compared with that at 120 kVp/30 mAs, demonstrating great potential for ultra-low-dose spectral-detector CT.

Long-range vibration sensor based on correlation analysis of optical frequency-domain reflectometry signals.

We present a novel method to achieve a space-resolved long- range vibration detection system based on the correlation analysis of the optical frequency-domain reflectometry (OFDR) signals. By performing two separate measurements of the vibrated and non-vibrated states on a test fiber, the vibration frequency and position of a vibration event can be obtained by analyzing the cross-correlation between beat signals of the vibrated and non-vibrated states in a spatial domain, where the beat signals are generated from interferences between local Rayleigh backscattering signals of the test fiber and local light oscillator. Using the proposed technique, we constructed a standard single-mode fiber based vibration sensor that can have a dynamic range of 12 km and a measurable vibration frequency up to 2 kHz with a spatial resolution of 5 m. Moreover, preliminarily investigation results of two vibration events located at different positions along the test fiber are also reported.

Optical fiber sensor based on a radio frequency Mach-Zehnder interferometer.

This Letter proposes an optical fiber radio frequency (RF) Mach-Zehnder interferometer (MZI) for sensing applications. An RF modulated laser source is injected into an optical fiber RF-MZI and collected by a photodiode. The interference pattern is observed in the RF domain by sweeping the frequency using a network analyzer. The proposed sensor has a linear response to applied temperature change. In addition, the sensitivity, observation frequency range, and the length of the sensing arm are discussed.

Radio frequency interrogated actively mode-locked fiber ring laser for sensing application.

This paper proposes an actively mode-locked fiber ring laser for sensing applications. Mode-locking of the laser is achieved by driving an electro-optic amplitude modulator at an RF corresponding to the fundamental beat frequency between the longitudinal modes. The change of the cavity length produces a frequency comb around the beat frequencies. The frequency separation of the comb is found to be linearly proportional to the cavity length change. The sensing mechanism of the device is shown. Temperature measurement is demonstrated using the proposed actively mode-locked fiber ring laser.