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An indispensable step in the imaging of Tomographic Synthetic Aperture Radar (TomoSAR) in spectral analysis or Compressive Sensing (CS) technology is estimating the perpendicular baselines in the Perpendicular Line Of Sight (PLOS) in deramping operations. To avoid this procedure, we introduce a Beam Forming (BF) method in the spatial domain that scans for TomoSAR focusing in the PLOS direction. Because of the sophisticated structure of buildings in urban areas, multipass high-resolution SAR images suffer from discrepancies in the look and incidence angles as well as speckle noise. As a result, it is challenging to precisely coregister all the homologous points in the identical pixels of multipass SAR images. To identify the most relevant pixels with respect to both amplitude and phase when BF imaging is implemented, we propose an inconsistency criterion for specific pixels using the joint phase and amplitude of pixels in a window. By minimizing the inconsistency criterion, homologous points with high accuracy can be identified by focusing on TomoSAR imaging. We used simulation and real data from a multipass X-band airborne TomoSAR system in China to test the effectiveness of the proposed method. Experimental results show that the peak of the reflectivity profile via conventional tomographic imaging is about 15.63 m, whereas that by the proposed method is 16.88 m, which is very close to the actual height of the 18 m building. The results demonstrate the feasibility of improving the focusing power of scatterers in the PLOS direction and extracting the threedimensional outliers of buildings.

Using azimuth beam steering, space-borne Synthetic Aperture Radar (SAR) can observe from multiple azimuth angle in single pass. During multiple azimuth angle observation, the satellite orbit is equivalent to long three-dimensional (3-D) curvilinear array, which has the potential for 3-D imaging. Sampling by space-borne multiple azimuth angle SAR is sparse in height dimension, which makes unambiguous 3-D imaging by 3-D fast Fourier transform infeasible. Besides, the complex relationship between the targets’projection in multi-angle SAR images and the height error is difficult to determine. To overcome this limitation, in this paper, we present a 3-D imaging method based on joint multiple azimuth angle Doppler frequency rate estimation. First, a relationship is proposed between the height error and Doppler frequency rate at different azimuth angle. Then, the Doppler frequency modulation rate error is estimated by Map Drift (MD) technique. Next, the height estimation results of different azimuth angle are combined to improve the estimation accuracy. From the estimated height and the target location in the SAR images, 3-D geometric information is retrieved and 3-D imaging is achieved. Our simulation experiments validate that the height estimation can achieve an accuracy of few meters with the proposed method.

Objective: Microneedling with topical tranexamic acid (TXA) is a novel treatment option for melasma; however, the efficacy and safety of this combined administration therapy is in controversial. This study is conducted to address this issue of this technique in melasma. Methods: An extensive literature review was performed to identify relevant trials, including randomized split‐face studies, randomized controlled trials and prospective non‐randomized split‐face studies, comparing microneedling plus topical TXA to routine treatments or placebo. The primary outcomes were changes of the Melasma Area Severity Index (MASI)/modified MASI (mMASI)/hemi MASI between before and after treatment, as well as the changes between a particular treatment and microneedling plus TXA. The mean differences (MDs) and 95% confidence intervals (CIs) were calculated for the reduction of melasma severity scores from baseline to each time point. In contrast, the standard mean differences (SMDs) and 95% CIs were calculated for the differences in reduction in melasma severity scores between the experimental and control groups at each time point. Results: A total of 16 trials were included in the systematic review and data synthesis. The pooled analysis demonstrated that MASI, mMASI, and hemiMASI scores decreased significantly at 4 weeks (MD = 1.85; 95% CI = 1.15–2.54), 8 weeks (MD = 3.28; 95% CI = 2.31–4.24), 12 weeks (MD = 4.73; 95% CI = 2.79–6.50), 16 weeks (MD = 3.18; 95% CI = 1.50–4.85), and 20 weeks (MD = 3.20; 95% CI = 1.95–4.46) after treatment when compared with baseline. The reduction in melasma severity scores of microneedling with TXA group at 4 weeks was more significant than the routine treatment group (SMD = 0.97; 95% CI = 0.09–1.86), while insignificant at 8 weeks (SMD = 1.21; 95% CI = −0.17 to 2.59), 12 weeks (SMD = 0.63; 95% CI = −0.03 to 1.29), 16 weeks (SMD = 0.61; 95% CI = −2.85 to 4.07), or 20 weeks (SMD = 1.04; 95% CI = −1.28 to 3.36). Conclusion: Despite the high heterogeneity across these studies, the current findings indicated that microneedling with topical TXA is an alternative treatment option for melasma treatment; and more well‐designed studies are needed to confirm it. [ABSTRACT FROM AUTHOR]

Objective: The ability of D‐dimer to diagnose periprosthetic joint infection (PJI) before revision hip or knee arthroplasty is still controversial, and the differences in diagnostic ability between serum‐ or plasma‐based assays of D‐dimer and fibrin (fibrinogen) degradation product (FDP) are uncertain. The prospective parallel study was performed to determine the ability of D‐dimer to diagnose PJI before revision hip or knee arthroplasty, and the differences in diagnostic ability between serum‐ or plasma‐based assays of D‐dimer and FDP. Methods: Patients undergoing knee or hip arthroplasty at our institution were prospectively enrolled into the following groups: those without inflammatory diseases who were undergoing primary arthroplasty ("Prim" group), those with inflammatory arthritis who were undergoing primary arthroplasty ("Prim/Inflam"), those undergoing revision arthroplasty because of aseptic failure ("Rev/Asept"), or those undergoing revision arthroplasty because of PJI ("Rev/PJI"). The ability of preoperative levels of D‐dimer or FDP in serum or plasma to diagnose PJI in each group was assessed using areas under receiver operating characteristic curves (AUCs) and other diagnostic performance indicators. The diagnostic performance of these assays was compared with that of C‐reactive protein (CRP) and erythrocyte sedimentation rate (ESR). Results: In the final analysis, Prim included 42 patients; Prim/Inflam, 40; Rev./Asept, 62; and Rev./PJI, 47. D‐dimer assays led to AUCs of 0.635 in serum and 0.573 in plasma, compared to 0.593 and 0.607 for FDP. Even in combination with CRP or ESR, these assays failed to perform as well as the combination of CRP and ESR for diagnosing PJI. Conclusion: Levels of D‐dimer or FDP in serum or plasma, whether used alone or together with CRP or ESR, are unreliable for diagnosing PJI before revision arthroplasty. [ABSTRACT FROM AUTHOR]