Suppression of wavelength-dependent polarization fading using hybrid-polarization scheme in OFDR.

What we believe to be a new hybrid-polarization diversity scheme which can eliminate the polarization state variation caused by wavelength tuning of laser in optical frequency domain reflectometry is proposed in the paper. In the scheme, a 45° polarizer is used to maintain the polarization of signals. It decreases the polarization angle fluctuation to 2.81° and realizes a -145 dB test sensitivity with a 32 dB Rayleigh scattering signal-to-noise ratio in a 10 m fiber single test. The polarization fading suppression is achieved for tests with a large wavelength tuning range from 1480 nm to 1640 nm. Meanwhile, a 6 µm spatial resolution is also achieved. The proposed scheme can be applied to the structure measurement of high-precision optical fiber devices with high spatial resolution and sensitivity.

Design, Synthesis and Evaluation of Fluorescent Properties of Benzothiazole Derivatives.

Fluorescence imaging is conducive to establish a bridge between molecular biology and clinical medicine, and provides new tools for disease process research, early diagnosis, and efficacy evaluation, because of the advantages of rapid imaging and nondestructive detection. Herein, a series of fluorescent molecules with thiadiazole, or thiazole, or benzothiazole cores were designed and synthesized to develop more excellent fluorescent molecules in bio-imaging. According to theoretical and experimental methods, we found that benzothiazole derivative 14 B with conjugate expansion by (4-aminophenyl) ethynyl group was the most excellent fluorescent molecule among all the investigated compounds and exhibited low cytotoxicity and strong blue and green fluorescence by confocal cell imaging.

Impact of signs and symptoms on the prognosis of patients with HFmrEF.

BACKGROUND: Worsening of heart failure (HF) symptoms is the leading cause of medical contact and hospitalization of patients with mildly reduced ejection fraction (HFmrEF). The prognostic value of signs and symptoms for patients with HFmrEF is currently unclear. This study investigated the prognostic impact of signs and symptoms in HFmrEF patients. METHODS: A Cox proportional risk regression model analyzed the relationship between the number of signs/symptoms and outcomes in 1691 hospitalized HFmrEF patients. Ten significant signs and symptoms were included. Patients were divided into three groups (A: ≤2, B: 3-5, C: ≥6 signs/symptoms). Stratified analysis on male and female patients was performed. The primary endpoint was all-cause mortality, and the secondary outcome was a composite of cardiovascular death and heart failure readmission (CV events) post-discharge. RESULTS: After a median follow-up of 33 months, all-cause mortality occurred in 457 patients and CV events occurred in 977 patients. Incidence of all-cause mortality was 20.7%, 32.3%* and 49.4%*† in group A, B and C of male patients, (*P < 0.05 vs. A, †P < 0.05 vs. B) and 18.8%, 33.6% and 55.8%* in group A, B and C of female patients. Incidence of CV events was 64.8%, 70.1%* and 87.5%* in group A, B and C of male patients, 61.9%, 75.3%, and 86.1%* in group A, B and C of female patients. Multivariate Cox regression showed older age, renal insufficiency, higher number of signs and symptoms (≥ 3, hazard ratio [HR] 1.317, 95% confidence interval [CI] 1.070-1.621, P = 0.009; ≥6, HR 1.982, 95% CI 1.402-2.801, P < 0.001), myocardial infarction, stroke, faster heart rate on admission, and diabetes were independently associated with all-cause mortality(all P < 0.05). Similarly, higher number of signs and symptoms (≥ 3, HR 1.271, 95% CI 1.119-1.443, P < 0.001; ≥6, HR 1.955, 95% CI 1.524-2.508, P < 0.001), older age, renal insufficiency, atrial fibrillation, and diabetes were independently associated with cardiovascular events (all P < 0.05). CONCLUSIONS: Higher number of symptoms and signs is associated with increased risk of all-cause mortality and CV events in HFmrEF patients. Our results highlight the prognostic importance of careful inquiry on HF symptoms and related physical examination in HFmrEF patients.

Phase noise elimination in frequency sweeping interferometry based on a common-path interferometer.

We propose a common-path interferometer (CPI) method to suppress the ambient and laser phase noise in frequency sweeping interferometry. The CPI realizes the multiplexing of the main and auxiliary interferometer to ensure the common-mode characteristic of the interference phase noise, which can be eliminated by signal mixing. In experiments, we obtain a dynamic range of up to 110 dB. Compared with the compensation method using a separated auxiliary interferometer, the CPI method improves the dynamic range by 10 dB and is immune to ambient noise. The proposed method enables high-precision distributed polarization measurements of optical fibers and devices.

Beyond a 107 range-resolution-1 product in an OFDR based on a periodic phase noise estimation method.

We present and demonstrate a method based on a periodic phase noise estimation in an optical frequency domain reflectometry (OFDR) capable of a beyond 107 range-resolution-1 product (RRP) for the first time, which corresponds to 2.5 × improvement compared with the state-of-the-art. The moving average filter is employed to suppress the amplification of noise in the derivation process. Further, with the help of a third-order Taylor expansion, this method provides a highly precise estimation of periodic phase noise, which is the main factor impacting the performance of OFDR systems with medium-to-long measurement range combined with a submillimeter spatial resolution. A spatial resolution within 535 µm over the measurement range of 8 km is obtained. The proposed method offers a promising technique for fiber network monitoring and sensing applications.

Rationale and Design of the ADIDAS Study: Association Between Dapagliflozin-Induced Improvement and Anemia in Heart Failure Patients.

BACKGROUND: Heart failure (HF) is one of the most serious health concerns worldwide. Anemia is a highly prevalent comorbidity and outcome predictor in HF patients. Sodium glucose co-transport 2 (SGLT2) inhibitors have been demonstrated to reduce the risk of cardiovascular death and HF hospitalization in HF patients. PURPOSE: This investigator-initiated, interventional, prospective, double-blind, multicenter study is designed to investigate whether anemia correction is one of the prerequisites and determinants related to the beneficial effects of dapagliflozin in HF patients. METHODS AND RESULTS: Up to 2030 HF participants receiving standard care will be randomly assigned to either oral dapagliflozin 10 mg once daily or placebo 10 mg once daily for 12 months. The primary outcome is the composite incidence of hospital admission for HF and all-cause death. Secondary outcomes include change in the Kansas City Cardiomyopathy Questionnaire (KCCQ) score and change in 6-min walk distance and hemoglobin level. Patients will be followed for 12 months after randomization. CONCLUSIONS: The ADIDAS trial offers an opportunity to assess the hemoglobin change and association between hemoglobin change and readmissions due to heart failure and all-cause death in patients with heart failure treated with dapagliflozin or placebo. This study could highlight if dynamic hemoglobin change is related to the outcome for HF patients. TRIAL REGISTRATION: ClinicalTrials.gov ; NCT04707261. Registration date, 2020/12/01, "retrospectively registered".

Terahertz image enhancing based on the physical model and multiscale retinex algorithm.

To settle the terahertz (THz) image degradation problem, we propose an effective enhancement method based on the physical model and multiscale retinex (MSR) algorithm. The overall enhancing process involves two parts: reconstruction and enhancement. First, the original THz images are reconstructed by a mathematical model, which is built and considered the THz absorption variate and Gaussian distribution of the beam. Then, the original images are processed by the proposed algorithm, which combines the atmospheric scattering model and optimized MSR algorithm. The proposed algorithm not only recovers the image scene radiance and removes haze, but also can make a compromise of the dynamic range of gray scale and edge enhancement of the image. Results on a variety of THz images demonstrate our method can effectively improve the quality of THz images and retain sufficient image details.

Calcaneous interlocking nail treatment for calcaneous fracture: a multiple center retrospective study.

BACKGROUND: Minimally invasive treatments for calcaneous fractures have the same outcomes and fewer complications. However, they are technically demanding, and there are a lack reduction tools. To overcome these problems, a calcaneous interlocking nail system was developed that can make reduction and fixation minimally invasive and effective. We retrospectively studied the calcaneous fracture variables intraoperatively and followed up to evaluate the outcomes of patients treated with the calcaneous interlocking nail system. METHODS: All patients in 7 institutions between October 2020 and May 2021 who had calcaneous fractures treated with calcaneous interlocking nails were retrospectively analyzed. The patient characteristics, including age, sex, injury mechanism, Sanders type classification, smoking status, and diabetes were recorded. The calcaneous interlocking nail and standard surgical technique were introduced. The intraoperative variables, including days waiting for surgery, surgery time, blood loss, incision length, and fluoroscopy time, were recorded. The outcomes of complications, AOFAS scores and VAS scores were recorded and compared with other similar studies. RESULTS: Fifty-nine patients were involved in this study; 54 were male; 5 were female; and they had an average age of 47.5 ± 9.2 years (range 25-70). 2 of these fractures were Sanders type I, 28 of these fractures were Sanders type II, 27 of these fractures were Sanders type III, and 2 of these were Sanders type IV. The surgery time was 131.9 ± 50.5 (30-240) minutes on average. The blood loss was 36.9 ± 41.1 (1-250) ml. The average incision length was 3.5 ± 1.8 (1-8) cm; 57 were sinus tarsi incisions; and 2 were closed fixations without incisions. The average fluoroscopy time was 12.3 ± 3.6 (10-25) seconds during the surgery. The VAS score of patients on the day after surgery was 2.4 ± 0.7 (1-3). The AOFAS ankle-hindfoot score in patients who had a follow-up of at 12 months was 93.3 ± 3.6(85-99). During the follow-up, all patients' functional outcomes were good. One patient had a superficial infection. The rate of complications of the 59 patients was 1.7% (1/59). CONCLUSION: The calcaneous interlocking nail system can have satisfactory reduction and fixation in calcaneous fractures, even in Sanders type IV. The outcomes of follow-up showed good function. The calcaneous interlocking nail could be an alternative method for minimally invasive calcaneous fracture fixation.

Toxicological Study on Chiral Fluoxetine Exposure to Adult Zebrafish (Danio rerio): Enantioselective and Sexual Mechanism on Disruption of the Brain Serotonergic System.

The increasing number of people with depression worldwide has led to concerns regarding antidepressant contamination in aquatic environments, which could have the risk of negative effects on aquatic organisms. Chirality increases its toxicity potentials. Accordingly, we investigated the negative effects of racemic (rac-), R-, and S-FX at environmental levels (100 ng/L) on the brain serotonergic system in zebrafish (Danio rerio) for 42 days. Additionally, we measured the whole-body concentrations of FX and norfluoxetine (NFX). We found that S-FX exposure disrupted the brain serotonergic system more severely than rac- and R-FX exposure. The mechanism underlying this disruption induced by S-FX was sex-specific, with female zebrafish showing disruption of the serotonin (5-HT) release process but male zebrafish showing disruption of the 5-HT synthesis process. In addition, enantioselective enrichment and biotransformation (R-FX to R-NFX and S-FX to S-NFX) occurred in zebrafish. Sex-specific accumulation was also observed, with higher concentrations in females. Our study provides evidence for enantiomer- and sex-specific effects of FX exposure at biologically relevant concentrations. More broadly, our study demonstrated that SSRI antidepressants, such as FX, can affect aquatic life by causing important shifts in not only their active sites of the serotonin transporter.

Synthesis and biological evaluation of 2,5-diaryl-1,3,4-oxadiazole derivatives as novel Src homology 2 domain-containing protein tyrosine phosphatase 2 (SHP2) inhibitors.

The Src homology-2 domain containing-protein tyrosine phosphatase-2 (SHP2) is a convergent node for oncogenic cell-signaling cascades including the PD-L1/PD-1 pathway. As an oncoprotein as well as a potential immunomodulator, SHP2 has now emerged as an attractive target for novel anti-cancer agents. Although significant progress has been made in identifying chemotypes of SHP2 inhibitors, these specific compounds might not be clinically useful to inhibit frequently encountered mutated SHP2 variants. Consequently, it is highly desirable to develop chemically different SHP2 inhibitors sensitive to SHP2 mutants. This work developed a new type of SHP2 inhibitors with 2,5-diaryl-1,3,4-oxadiazole scaffold. The representative compound 6l exhibited SHP2 inhibitory activity with IC50 of 2.73 ± 0.20 µM, showed about 1.56-fold, 5.26-fold, and 7.36-fold selectivity for SHP2 over SHP1, PTP1B and TCPTP respectively. Further investigations confirmed that 6l behaved as mixed-type inhibitor sensitive to leukemia cell TF-1 and inhibited SHP2 mediated cell signaling and proliferation. Molecular dynamics simulation provided more detailed information on the binding modes of compounds and SHP2 protein. These preliminary results could provide a possible opportunity for the development of novel SHP2 inhibitors sensitive to SHP2 mutants with optimal potency and improved pharmacological properties.

Underwater fiber-optic salinity and pressure sensor based on surface plasmon resonance and multimode interference.

In this paper, an underwater fiber-optic sensor based on surface plasmon resonance (SPR) and multimode interference (MMI) is presented for simultaneous measurement of salinity and pressure. This sensor is based on a single-mode-multimode-single-mode-multimode-single-mode structure with a gold film deposited on the middle single-mode fiber and the fiber structure is wrapped around an elastic cylinder to constitute a sensing head. In the fiber structure, the SPR region produces a resonance dip to measure salinity, and the independent MMI region achieves narrow and salinity-insensitive interference dips to measure pressure. Performance of the sensor is predicted by calculation, and the MMI spectrum is simulated by using the finite-difference beam propagation method. By experimental tests for salinity and pressure, the sensitivities of 0.36 nm/‰ and -1.42nm/MPa are achieved, respectively, and the cross talk is also proved to be insignificant. This study provides an important application direction for SPR-MMI sensors and a prospective method for ocean detection.

Strain distribution characteristics of sensing fiber and influence on sensitivity of a fiber-optic disk accelerometer.

In a fiber-optic disk accelerometer, the strain distribution of sensing fiber is crucial for the improvement of sensitivity. The distribution characteristics of axial and radial strain in the sensing fiber are analyzed by the finite-element method, and the influence of strain distribution on the sensitivity of accelerometer is studied. Sensors with different outer radii of sensing fiber coils are designed and manufactured, and their performance is tested. The resonant frequencies are greater than 200 Hz, and the sensitivity increases as the outer radius of the sensing fiber coil increases. The dynamic range of the sensor with maximum sensitivity is 145.8 dB@100 Hz, and the transverse cross talk is 32.5 dB. Among the sensing fiber strain calculation methods we tested to predict the value of sensitivity, using the strain of sensing fiber directly obtained by the finite-element analysis method shows the smallest error with experimental results (within 7%). It is concluded that in the optical fiber strain disk, the absolute values of axial strain and radial strain of sensing fiber decrease with the increase of disk radius, while the signs of axial strain and radial strain of the ipsilateral sensing fiber are opposite and remain unchanged. The sensitivity can be further improved by optimizing the inner and outer radius of the sensing fiber coils, which is very important for the research and design of high-sensitivity fiber-optic accelerometers.

A TADF Emitter Featuring Linearly Arranged Spiro-Donor and Spiro-Acceptor Groups: Efficient Nondoped and Doped Deep-Blue OLEDs with CIEy <0.1.

Reported herein is a molecular design strategy of deep-blue emitters for resolving the lack of highly efficient deep-blue organic light-emitting diodes (OLEDs) featuring CIEy (Commission Internationale de l'Eclairage) color coordinates matching the display requirements (<0.1). The strategy is to combine weak spiro-donor and spiro-acceptor groups into a linear donor-π-acceptor type of thermally-activated delayed fluorescence molecule through a sterically bulky π-spacer. The strategy endows an emitter with deep-blue emission, a narrower emission bandwidth (51 nm in toluene), a high photoluminescence quantum yield (0.95 in toluene), weak concentration quenching, and efficient triplet-exciton utilization, which are all attractive characteristics for emitters of deep-blue OLEDs with lower CIEy coordinates. Owing to the rational design, the emitter has realized not only highly efficient doped deep-blue OLEDs with external quantum efficiencies (EQEs) up to 25.4 % and CIEy less than 0.1 but also so far the most efficient nondoped deep-blue OLED (EQE up to 22.5 %) with CIEy less than 0.1.

Image fusion based on multiscale transform and sparse representation to enhance terahertz images.

High-quality terahertz (THz) images are vital to integrated circuit (IC) manufacturing. Due to the unique sensitivity of THz waves to different materials, the images obtained from the point-spread function (PSF) model have fewer image details and less texture information in some frequency bands. This paper presents an image fusion technique to enhance the resolution of THz IC images. The source images obtained from the PSF model are processed by a fusion method combining a multiscale transform (MST) and sparse representation (SR). The low-pass band is handled by sparse representation, and the high-pass band is fused by the conventional "max-absolute" rule. From both objective and visual perspectives, four popular multiscale transforms-the Laplacian pyramid, the ratio of low-pass pyramids, the dual-tree complex wavelet transform and the curvelet transform-are thoroughly compared at different decomposition levels ranging from one to four. This work demonstrates the feasibility of using image fusion to enhance the resolution of THz IC images.

Convolutional neural network model based on terahertz imaging for integrated circuit defect detections.

Detection of integrated circuit (IC) defects is vital in IC manufacturing. Traditional defect detection methods have relied on scanning electron microscopy and X-ray imaging techniques that are time consuming and destructive. Hence, in this paper we considered terahertz imaging as a label-free and nondestructive alternative. This study aimed to use a convolutional neural network model (CNN) to improve the performance of the terahertz imaging IC detection system. First, we constructed a terahertz imaging IC dataset and analyzed it. Subsequently, a new CNN structure was proposed based on the VGG16 network. Finally, it was optimized based on its structure and dropout rate. The method proposed above can improve IC defects detection accuracy of THz imaging. Most significantly, this work will promote the application of terahertz imaging in practice and provide a foundation to further research in relevant fields.

Synthesis and biological evaluation of heterocyclic bis-aryl amides as novel Src homology 2 domain containing protein tyrosine phosphatase-2 (SHP2) inhibitors.

The Src homology-2 domain containing protein tyrosine phosphatase-2 (SHP2) is a convergent node for oncogenic cell-signaling cascades including the PD-L1/PD-1 pathway. Consequently, SHP2 has emerged as a compelling target for novel anti-cancer agents. Replacing one of phenyl ring in PTP1B inhibitor 1 with heterocyclic ring led to a series of heterocyclic bis-aryl amide derivatives. The representative compound 7b displayed SHP2 inhibitory activity with IC50 of 2.63 ± 0.08 µM, exhibited about 4-fold selectivity for SHP2 over TCPTP and had no detectable activity against SHP1 and PTP1B. These preliminary results could provide a possible opportunity for the development of novel SHP2 inhibitors with optimal potency and improved pharmacological properties.

Improved GNSS-Based Bistatic SAR Using Multi-Satellites Fusion: Analysis and Experimental Demonstration.

The Global Navigation Satellite System (GNSS)-based Bistatic Synthetic Aperture Radar (SAR) is getting more and more attention in remote sensing for its all-weather and real-time global observation capability. Its low range resolution results from the narrow signal bandwidth limits in its development. The configuration difference caused by the illumination angle and movement direction of the different satellites makes it possible to improve resolution by multi-satellite fusion. However, this also introduces new problems with the resolution-enhancing efficiency and increased computation brought about by the fusion. In this paper, we aim at effectively improving the resolution of the multi-satellite fusion system. To this purpose, firstly, the Point Spread Function (PSF) of the multi-satellite fusion system is analyzed, and focusing on the relationship between the fusion resolution and the geometric configuration and the number of satellites. Numerical simulation results show that, compared with multi-satellite fusion, dual-satellite fusion is a combination with higher resolution enhancement efficiency. Secondly, a method for dual-satellite fusion imaging based on optimized satellite selection is proposed. With the greedy algorithm, the selection is divided into two steps: in the first step, according to geometry configuration, the single-satellite with the optimal 2-D resolution is selected as the reference satellite; in the second step, the angles between the azimuthal vector of the reference satellite and the azimuthal vector of the other satellites were calculated by the traversal method, the satellite corresponding to the intersection angle which is closest to 90° is selected as the auxiliary satellite. The fused image was obtained by non-coherent addition of the images generated by the reference satellite and the auxiliary satellite, respectively. Finally, the GPS L1 real orbit multi-target simulation and experimental validation were conducted, respectively. The simulation results show that the 2-D resolution of the images produced by our proposed method is globally optimal 15 times and suboptimal 8 times out of 24 data sets. The experimental results show that the 2-D resolution of our proposed method is optimal in the scene, and the area of the resolution unit is reduced by 70.1% compared to the single-satellite's images. In the experiment, there are three navigation satellites for imaging, the time taken to the proposed method was 66.6% that of the traversal method. Simulations and experiments fully demonstrate the feasibility of the method.

Phylogenetic characterization of bromate-reducing microbial community enriched anaerobically from activated sludge.

Bromate is a weakly carcinogenic disinfection by-product generated from naturally existing bromide during ozonation. In order to uncover the phylogenetic diversity of bromate-reducing aquatic bacteria, the microbial mixed cultures were enriched anaerobically from various activated sludge samples with a high concentration of 3.6 mmol/L bromate which served as the electron acceptor in batch-fed reactors. Then the phylogenetic diversity was characterized by employing 16S rRNA gene-based clone libraries and high-throughput sequencing. Results showed that as highest as 48.65 mg/L [BrO3--Br] (0.61 mmol/L) could be reduced to Br- within an operational cycle of 48 h, indicating the presence of bromate-reducing bacteria. The microbial analysis based on 16S rRNA gene clone libraries indicated that the dominant bacteria in the enriched consortium were affiliated to the genera of Aeromonas, which had been reported and implied its functional application to reduce bromate. In addition, some other subdivisions of bromate-reducing bacteria were enriched at different operational cycles. The abundance of the genus Rivibacter belonging to Comamonadaceae were increased after 10 cycles enrichment, which might represent another type of novel bromate bio-reducers. The study provided new insights for the phylogenetic diversity of the bromate-reducing microorganisms while further researches are required to verify the bromate bio-reduction mechanism.

A Novel Method for Ocean Wind Speed Detection Based on Energy Distribution of Beidou Reflections.

The Global Navigation Satellite System Reflectometry (GNSS-R) technique exploits the characteristics of reflected GNSS signals to estimate the geophysical parameters of the earth's surface. This paper focuses on investigating the wind speed retrieval method using ocean scattered signals from a Beidou Geostationary Earth Orbit (GEO) satellite. Two new observables are proposed by computing the ratio of the low energy zone and the high energy zone of the delay waveform. Coastal experimental raw data from a Beidou GEO satellite are processed to establish the relationship between the energy-related observables and the sea surface wind. When the delay waveform normalized amplitude (this will be referred to as "threshold" in what follows) is 0.3, fitting results show that the coefficient of determination is more than 0.76 in the gentle wind scenario (<10 m/s), with a root mean square error (RMSE) of less than 1.0 m/s. In the Typhoon UTOR scenario (12.7 m/s~37.3 m/s), the correlation level exceeds 0.82 when the threshold is 0.25, with a RMSE of less than 3.10 m/s. Finally, the impact of the threshold and coherent integration time on wind speed retrieval is discussed to obtain an optimal result. When the coherent integration time is 50 milliseconds and the threshold is 0.15, the best wind speed retrieval error of 2.63 m/s and a correlation level of 0.871 are obtained in the UTOR scenario.

Co-axis digital holography based on sinusoidal phase modulation using generalized lock-in detection.

Sinusoidal phase modulating (SPM) interferometers are used to precisely measure complex light fields with simple interferometric setups. Recently, a generalized lock-in technique has been proposed for optimizing the signal extraction in phase-modulated interferometers. This article shows its applicability in digital holography as well as digital holographic interferometry. A compact homemade setup based on the Michelson interferometer was used to observe the scattering sample surface with a spatial resolution of 32 LP/mm; out-of-plane rotation was measured with a theoretical detection limit of 0.004°. The comparison between the generalized lock-in detection and traditional SPM interferometer method was done theoretically and experimentally.