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.

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.

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.

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.

Long noncoding RNA regulatory factor X3- antisense RNA 1 promotes non-small cell lung cancer via the microRNA-577/signal transducer and activator of transcription 3 axis.

Lung cancer is the most frequent malignancy, and non-small cell lung cancer (NSCLC) is its most common pathological type. Molecular targeted therapy has been testified to be effective in intervening in the occurrence and development of malignancies. This study investigates the effect of lncRNA Regulatory Factor X3- antisense RNA 1 (RFX3-AS1) in NSCLC progression. The RFX3-AS1 profile in NSCLC tissues and cells was measured by quantitative reverse transcription PCR (qRT-PCR). The RFX3-AS1 overexpression model was constructed. The cell counting kit-8 (CCK-8) experiment and cell colony formation assay were adopted to test cell viability. The cell apoptosis was determined by flow cytometry (FCM). Cell migration and invasion were monitored by the Transwell assay, and Western blot was implemented to verify the protein profiles of signal transducer and activator of transcription 3 (STAT3), E-cadherin, Vimentin and N-cadherin. In vivo, we validated the impact of RFX3-AS1 overexpression on the NSCLC xenograft mouse model. The targeting relationships between RFX3-AS1 and miR-577, miR-577 and STAT3 were confirmed by the dual-luciferase reporter assay. The results manifested that overexpressing RFX3-AS1 markedly facilitated NSCLC cell proliferation, migration, invasion and epithelial-mesenchymal transition (EMT), and suppressed cell apoptosis. In contrast, miR-577, which was a downstream target of RFX3-AS1, dramatically impeded the malignant biological behaviors of NSCLC cells. STAT3 was a direct target of miR-577, and it was negatively regulated by the latter. STAT3 activation reversed miR-577-mediated anti-tumor roles. In brief, RFX3-AS1 aggravated NSCLC progression by regulating the miR-577/STAT3 axis.

Evaluating the impact of personalized rehabilitation nursing intervention on postoperative recovery of respiratory function among thoracic surgery intensive care unit patients: A protocol for systematic review and meta-analysis.

BACKGROUND: Exercise tolerance and lung function can be improved by pulmonary rehabilitation. As a result, it may lower thoracic surgery intensive care unit (ICU) patients' postoperative problems and death. Enhanced recovery after surgery has advanced significantly in the perioperative care of thoracic surgery ICU patients in recent years, and it now plays an essential role in improving ICU patients' postoperative prognosis. Appropriate tailored rehabilitation nursing intervention is required to promote the postoperative recovery of respiratory function in thoracic surgery ICU patients. This study aims to look at the influence of tailored rehabilitation nurse intervention on postoperative respiratory function recovery in thoracic surgery ICU patients. METHODS: To find relevant papers, a comprehensive search of electronic databases will be conducted, including three English databases (PubMed, EMBASE, and the Cochrane Library) and two Chinese databases (Chinese National Knowledge Infrastructure and WanFang). Only research that has been published in either English or Chinese will be considered. The retrieval period will run from November 2021 to November 2021. We will look at randomized controlled trials (RCTs) studies that looked at the effect of a customized rehabilitation nursing intervention on the recovery of respiratory function in thoracic surgery ICU patients after surgery. Two writers will review the literature, retrieve study data, and assess the included studies' quality. Any disagreements will be settled via consensus. RevMan 5.3 will be used to do the meta-analysis. RESULTS: This research will offer high-quality data on the influence of customized rehabilitation nurse intervention on postoperative respiratory function recovery in thoracic surgery ICU patients. CONCLUSION: This study will look at whether a targeted rehabilitation nurse intervention might help thoracic surgery ICU patients recover their respiratory function more quickly after surgery. ETHICS AND DISSEMINATION: There will be no need for ethical approval. REGISTRATION NUMBER: December 12, 2021.osf.io/9rdu2/ (https://osf.io/9rdu2/).

Prevalence of Sialorrhea Among Amyotrophic Lateral Sclerosis Patients: A Systematic Review and Meta-Analysis.

BACKGROUND AND OBJECTIVES: Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative motor neuron disease (MND), and sialorrhea is a known symptom in patients with ALS, which may cause a social embarrassment and discomfort. However, people do not pay attention to sialorrhea up to now. This study is aimed at conducting a systematic review and meta-analysis of the pooled prevalence of sialorrhea in ALS patients all around the world and raising awareness of salivation. METHODS: We searched PubMed and EMBASE databases to obtain the comprehensive literatures which reported the prevalence of sialorrhea. We used AHRQ and NOS to evaluate the literature quality. Subgroup analyses were performed based on screening instruments and severity of sialorrhea. At the meantime, sensitivity analyses was also conducted to identify the source of heterogeneity. RESULTS: A total of 17 eligible studies which included 21 groups of data reported prevalence of sialorrhea. The pooled prevalence of sialorrhea among ALS patients was 30.8% (95% CI: 20.0%-44.2%). For studies using ALSFRS-R, direct questioning, postal survey, and ALSSoL average and ALSFRS-R, the pooled prevalence of sialorrhea was 22.7%, 25.8%, 29.8% and 52.0% respectively. According to the severity of sialorrhea, the prevalence of mild, moderate, and severe sialorrhea were 25.1%, 11.2%, and 10.5%, respectively. And none of the studies alone had a significant effect on the overall prevalence of sialorrhea after we eliminated each study separately in sensitivity analyses. CONCLUSIONS: Sialorrhea is a relatively common symptom in ALS patients with a comparatively high prevalence. In our study, we found that the prevalence of sialorrhea in ALS patients is relatively higher than the results based on direct questioning or postal survey. Therefore, we deduced that sialorrhea should be evaluated by more complex professional assessment scales to improve the quality of life and improve early prognosis of disease.

[Advances in bacterial Rieske non-heme iron ring-hydroxylating dioxygenases that initiate polycyclic aromatic hydrocarbons degradation].

Polycyclic aromatic hydrocarbons (PAHs) are a class of persistent organic pollutants, which have received widespread attentions due to their carcinogenic and mutagenic toxicity. The microbial degradation of PAHs are usually started from the hydroxylation, followed by dehydrogenation, ring cleavage and step-by-step removal of branched chains, and finally mineralized by the tricarboxylic acid cycle. Rieske type non-heme iron aromatic ring-hydroxylating dioxygenases (RHOs) or cytochrome P450 oxidases are responsible for the conversion of hydrophobic PAHs into hydrophilic derivatives by the ring hydroxylation. The ring hydroxylation is the first step of PAHs degradation and also one of the rate-limiting steps. Here, we review the distribution, substrate specificity, and substrate recognition mechanisms of RHOs, along with some techniques and methods used for the research of RHOs and PAHs.

Polarization-sensitive and active controllable electromagnetically induced transparency in U-shaped terahertz metamaterials.

Electromagnetically induced transparency (EIT) phenomenon is observed in simple metamaterial which consists of concentric double U-shaped resonators (USRs). The numerical and theoretical analysis reveals that EIT arises from the bright-bright mode coupling. The transmission spectra at different polarization angle of incident light shows that EIT transparency window is polarization sensitive. More interestingly, Fano resonance appears in the transmission spectrum at certain polarization angles. The sharp and asymmetric Fano lineshape is high valuable for sensing. The performance of sensor is investigated and the sensitivity is high up to 327 GHz/RIU. Furthermore, active control of EIT window is realized by incorporating photosensitive silicon. The proposed USR structure is simple and compact, which may find significant applications in tunable integrated devices such as biosensor, filters, and THz modulators.

Nek9,a sensitive immunohistochemical marker for Schwannian, melanocytic and myogenic tumours.

AIMS: In our previous study, striking Nek9 staining was observed in peripheral nerves for the first time. Therefore, in the current study, we aimed to detect Nek9 expression in peripheral nerve sheath tumours, melanocytic tumours and their mimics. METHODS: The expression of Nek9 was analysed in 234 mesenchymal tumours including schwannoma, neurofibroma, malignant peripheral nerve sheath tumour (MPNST), melanoma and their mimics adopting immunohistochemistry. In addition, S-100 and SOX10 were detected in all tumours. RESULTS: The results revealed an intense and diffuse staining of Nek9 in all schwannomas (30/30) and melanomas (20/20). The neurofibromas (86%, 19/22) and MPNSTs (76%, 18/21) showed a high frequency of positive Nek9 staining. Nek9 showed a comparable sensitivity to S-100, and better sensitivity and less specificity than that of SOX10. Among the histological mimics, Nek9 was only strongly and diffusely expressed in rhabdomyosarcomas (RSs) (97%,37/38) while negatively stained in most of the other tumours. It was noted that Nek9 immunoresponse was more diffuse than that of MyoD1 and myogenin in RS. CONCLUSIONS: In summary, Nek9 has a good sensitivity in the diagnosis of tumours with Schwannian, melanocytic and skeletal muscle differentiations. The immunohistochemical analysis of Nek9 expression may be helpful in the diagnosis and differential diagnosis of the aforementioned tumours.

[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.

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.

Cyclin-dependent kinase subunit 2 overexpression promotes tumor progression and predicts poor prognosis in uterine leiomyosarcoma.

Cyclin-dependent kinase subunit (CKS) 2 is a member of the CKS family, which plays an important role in the regulation of meiosis and mitosis. Overexpression of CKS2 has been reported in several types of tumors. However, few studies have investigated its role in uterine leiomyosarcoma (ULMS). In the present study, the expression of CKS2 in 38 cases of ULMS and 38 cases of uterine leiomyoma (ULM) was analyzed by immunohistochemistry. Moreover, the functional analysis of CKS2 was performed in ULMS cell lines. A significantly higher expression of CKS2 was found in ULMS tissues than in ULM tissues (P<0.01) and high CKS2 expression was associated with increased tumor size, low progesterone receptor expression and poor prognosis in patients with ULMS. Multivariate Cox regression analysis revealed that CKS2 expression status was an independent predictor of overall survival for ULMS. Furthermore, silencing of CKS2 in ULMS cells inhibited cell proliferation, colony formation, migration and invasion, and resulted in cell cycle arrest. In conclusion, the present study demonstrated that CKS2 may serve as a marker for the differential diagnosis of ULMS and ULM. In addition, it may act as an independent prognostic factor in patients with ULMS, and serve as a novel target for ULMS therapy.

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.

Magnetic-field sensor with self-reference characteristic based on a magnetic fluid and independent plasmonic dual resonances.

A magnetic-field sensor with self-reference characteristic based on metal-dielectric-metal (MDM) plasmonic waveguides and a magnetic fluid (MF) is proposed and theoretically investigated. Independent dual resonances are supported by the coupled resonator-waveguide system. The physical mechanisms of dual resonances are analyzed by the temporal coupled-mode theory. The transmission response to an external magnetic field is explored by using the remarkable tunability of the refractive index of the MF. Based on the different dependence of two resonances on the external field, a magnetic-field sensor with self-reference characteristic is achieved. The magnetic-field nanosensor shows an excellent performance with a high sensitivity of 27 pm/Oe, i.e., 270 pm/mT. The proposed sensor takes advantage of the refractive-index tunability of the MF and the compactness of the MDM waveguide structure. This research may open new opportunities to design nanoscale magnetic sensors with good performance.

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.

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.

Multiple Fano resonances with flexible tunablity based on symmetry-breaking resonators.

A symmetry-breaking nanostructure is proposed to achieve multiple Fano resonances. The nanostructure consists of an asymmetric ring resonator coupled to a plasmonic waveguide. The broken symmetry is introduced by deviating the centers of regular ring. New resonant modes that are not accessible through a regular symmetric ring cavity are excited. Thus, one asymmetric cavity can provide more than one resonant mode with the same mode order. As a result, the interval of Fano resonances is greatly reduced. By combining different rings with different degrees of asymmetry, multiple Fano resonances are generated. Those Fano resonances have different dependences on structural parameters due to their different physical origin. The resonance frequency and resonance peak number can be arbitrarily adjusted by changing the degree of asymmetry. This research may provide new opportunities to design on-chip optical devices with great tuning performance.

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.