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For ultra-high-resolution (UHR) squint spotlight airborne synthetic aperture radar (SAR), the severe range-azimuth coupling caused by squint mode and the spatial and frequency dependence of the motion error brought by ultra-wide bandwidth both make it difficult to obtain satisfactory imaging results. Although some autofocus methods for squint airborne SAR have been presented in the published literature, their practical applicability in UHR situations remains limited. In this article, a new 2D wavenumber domain autofocus method combined with the Omega-K algorithm dedicated to UHR squint spotlight airborne SAR is proposed. First, we analyze the dependence of range envelope shift error (RESE) and range defocus on the squint angle and then propose a new spectrum modification strategy, after which the spectrum transforms into a quasi-side-looking one. The accuracy of estimation and compensation can be improved significantly in this way. Then, the 2D phase error can be calculated with the 1D estimated error by the mapping relationship, and after that the 2D compensation is performed in the wavenumber domain. Furthermore, the image-blocking technique and range-dependent motion error compensation method are embedded to accommodate the spatial-variant motion error for UHR cases. Simulations are carried out to verify the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

Objectives: This study aimed to investigate the pharmacokinetic characteristics of siponimod in healthy volunteers and patients with MS based on aggregated data from published clinical trials, and to explore the factors influencing siponimod exposure.Methods: A total of 476 siponimod plasma concentrations aggregated from 28 dosage groups (corresponding to 294 healthy volunteers and 207 patients with MS) were collected from published clinical trials. Population pharmacokinetic (PPK) analysis was performed using a nonlinear, mixed-effect modeling approach. The pharmacokinetic properties of siponimod in healthy volunteers and patients with MS were compared, and the influence of covariates on siponimod exposure was evaluated using both PPK analysis and noncompartmental analysis (NCA).Results: A one-compartment model with first-order absorption and elimination adequately described siponimod pharmacokinetics. The typical population parameter estimates of clearance (CL/F), apparent volume of distribution (V/F), and absorption rate constant (ka) were 3.17 L/h, 112.70 L, and 0.38 h−1, respectively. An 11.85% lower siponimod clearance was estimated for patients with MS relative to healthy volunteers. Subgroup analyses using NCA assessments revealed that siponimod presented an accumulation index of approximately 2 after multiple administration. Compared with nonobese participants, obese participants had a relatively lower dose-corrected area under the concentration-time curve (AUC0-∞/D) (0.31 vs. 0.42 h/L) and V/F (120.95 vs. 133.75 L), and a relatively higher CL/F (3.25 vs. 3.21 L/h). Participants with CYP2C9*2/*3, *1/*3, and *3/*3 genotypes experienced an increased (1.3- and 3.4-fold, respectively) AUC0-∞/D and a decreased (0.7- and 0.3-fold, respectively) CL/F compared with those in participants with the CYP2C9*1/*1, *1*2, and *2*2 genotypes. Fluconazole combination led to a decrease in CL/F (approximately 0.5 times) and an increase in AUC0-∞/D (approximately 1.3 times).Conclusion: Siponimod pharmacokinetic properties in healthy volunteers and patients with MS were explored using complementary model-based meta-analysis (MBMA) and NCA approaches. A slightly lower siponimod clearance was observed in patients with MS than in healthy volunteers. The dosage regimen, body mass index, CYP2C9 genetic polymorphism and fluconazole combination may had influences on siponimod pharmacokinetics. Such model paves the road to more population-based analyses in different patient populations with MS to quantify the effect of any influencing factors on siponimod pharmacokinetics.

A dual-band LFM-CW radar scheme which is based on photonic stretch processing is proposed. The receiver which is based on a photonic frequency down-converter is able to receive the radar echoes of two bands with a single hardware. A dual polarization quadrature phase shift keying modulator is employed to implement the modulation scheme. The reference signals and echoes of two bands are modulated to orthogonally polarized light waves and sent to a Pol-demux coherent receiver through an amplifier and a filter, respectively, to perform stretch processing. In the transmitter, the reference and transmitted LFM signals with high frequency and wide bandwidth are generated by a photonic-assisted frequency multiplication module. Meanwhile, the generated signal is delayed before transmission. Thus, at the output of the coherent receiver, IF signals corresponding to two bands can be separated in the frequency domain. An experimental system operating in Cand Ku-bands with transmitting signal bandwidths of 1 and 2 GHz, respectively, is demonstrated and evaluated via a series of inverse synthetic aperture radar imaging tests, and the sampling rate of analog to digital converters is 100 MSa/s. The results show that the microwave photonics technology can provide solutions for receiving dual-band signal with a single hardware platform.

Objective: To perform visual analysis of the related researches on exercise regulation of muscle, liver, and lipid exerkines, and discuss the research hotspots and frontiers in this field. Methods: The data source is the relevant research literature on exercise regulation of muscle, liver, and lipid exerkines included in the core databases of "Web of Science" and "CNKI" from 2004 to 2020. Scientific knowledge map is drawn with the help of "CNKI" visual analysis function and "Cite Space V" software. Results: 1) A total of 166 domestic papers were included on relevant research, showing a slow upward trend on the whole. The main research hotspots are the regulation of adipokines by aerobic exercise to improve insulin resistance, the effects of different exercise modes and loads on the expression of muscle, liver, and lipid exerkines, and regulatory effects of muscle, liver and lipid exerkines on metabolic diseases. 2) A total of 632 overseas papers were included on relevant research, which are still in the initial stage of development. The United States ranks first with 156 papers, and the cooperation between countries is relatively simple. Frontiers in Physiology is the journal with the most publications (19 articles). Productive authors and teams are concentrated in the Federal University of Sao Paulo, Brazil. The research frontier keywords are activation, irisin and biomarker. The research hotspots mainly focus on the effects of exercise-regulated muscle, liver and lipid exerkines on obesity, the effects of exercise-regulated muscle, liver and lipid exerkines on cardiovascular diseases, and the effects of aerobic exercise on the regulation of myokines on brain function. Conclusion: Aerobic exercise can regulate the expression of adipokines and improve insulin sensitivity; different exercise programs can regulate the differential expression of muscle, liver and lipid exerkines; muscle, liver and lipid exerkines can reduce the risk factors of metabolic diseases. Exercise can up regulate leptin expression and regulate TNF- a Level, improve obesity, mediate muscle, liver and lipid ex-erkines, inhibits cell apoptosis, and alleviates the process of cardiovascular disease, and improve the expression of myokines to improve brain function. In the future, it is necessary to enhance the depth and cooperation density of research on exerc.ise regulation of muscle, liver and lipid exerkines, strengthen the research on the mechanism of muscle, liver and lipid exerkines to prevent and treat metabolic diseases such as diabetes, obesity, cardiovascular disease and brain disease, explore the exact exercise program for the best effect of muscle, liver and lipid exerkines and its new type of biomarkers fur detection and prognosis diagnosis, and systematically sort out the relevant signal pathways that exercise regulates muscle, liver and lipid exerkines and diseases. [ABSTRACT FROM AUTHOR]