Joint equalization of frequency offset and phase noise using two-stage cascaded extended Kalman filter for discrete spectrum 16/64APSK NFDM systems.

For the discrete spectrum nonlinear frequency division multiplexing (DS-NFDM) 16/64 amplitude phase shift keying (APSK) system, the inevitable laser impairments including frequency offset (FO) and carrier phase noise (CPN) would cause different rotations of the received signal constellations. In addition, the combined effect of FO and amplifier spontaneous emission (ASE) noise induces the eigenvalue shift, accordingly the residual channel impairment (RCI) is inevitably yielded. To address the above problems, we deduce the joint impairment model of FO, CPN and RCI, and then propose a joint equalization scheme using two-stage cascaded extended Kalman filter (TSC-EKF) for these impairments. It performs frequency offset compensation in the first stage, subsequently carries out joint equalization of CPN and RCI in the second stage. Meanwhile, the minimum Euclidean distance and phase difference between the received symbols and the ideal 16/64APSK constellations are ingeniously fused to calculate the innovations of TSC-EKF. The effectiveness has been verified by 2 GBaud DS-NFDM 16/64 APSK simulations and DS-NFDM 16APSK transmission experiments. The results demonstrate that when performing the joint equalization of FO, CPN and RCI, the maximum FOE range of TSC-EKF scheme achieves 1.2 and 9.6 times as that of nonlinear frequency domain (NFD) scheme and fast Fourier transform -Like (FFT-Like) scheme, respectively. Furthermore, its maximum LW tolerance reaches 3.3 times as that of the M-th power scheme. Importantly, the complexity of TSC-EKF is 63.4% as that of NFD scheme and on an order of O(N).

Percutaneous Endoscopic Lumbar Discectomy for Calcified Lumbar Disc Herniation: A Retrospective Cohort Study, Systematic Review and Meta-Analysis.

BACKGROUND: Calcified lumbar disc herniation (CLDH) is a subtype characterized by calcification, leading to increased surgical complexity. Percutaneous endoscopic lumbar discectomy (PELD) is a minimally invasive technique, but its effectiveness and complications in CLDH patients remain to be fully evaluated. OBJECTIVE: To assess the effectiveness and complications of PELD in treating CLDH patients. STUDY DESIGN: A retrospective cohort study combined with a systematic review and meta-analysis. SETTING: Department of Pain Medicine, an affiliated hospital of a university. METHODS: Data from patients who underwent PELD in our department between March 2020 and May 2021 were collected. Forty CLDH patients were included in the study group, and equally matched cases with uncalcified lumbar disc herniation (UCLDH) served as controls. A systematic search was conducted on October 5, 2022, using EMBASE, PubMed, Cochrane Library, the China Biology Medicine disk, the China National Knowledge Infrastructure, and the Wanfang databases, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A random-effects model was used to calculate pooled results. RESULTS: Eighty patients were included in the retrospective cohort, and 41 studies were included in the meta-analysis. Both the retrospective cohort and meta-analysis consistently showed a significant decrease in visual analog scale (VAS) and Oswestry Disability Index (ODI) scores in the CLDH group after the operation. In the retrospective cohort, the excellent or good rate according to the MacNab classification was 85%, with no reported complications. The meta-analysis revealed a pooled excellent or good rate of 91.8% and a low complication rate of 2.9%. Combining the findings from our retrospective cohort and meta-analysis, we observed that the CLDH group had longer operation times and slightly higher postoperative ODI scores compared to the UCLDH group. LIMITATIONS: Small sample size and lack of long-term follow-up in the retrospective cohort, as well as limited inclusion of comparative studies in the meta-analysis. CONCLUSION: PELD is an effective and safe treatment option for CLDH patients. In comparison to UCLDH patients, CLDH patients may experience longer operation times and slightly slower functional recovery than those with UCLDH.

ASE noise mitigation with digital frequency offset loading for discrete spectrum nonlinear frequency division multiplexing systems.

We propose an amplified spontaneous emission (ASE) noise mitigation scheme utilizing digital frequency offset loading (DFO-loading) for discrete spectrum nonlinear frequency division multiplexing (DS-NFDM) systems. Firstly, based on the one-to-one mapping relationship between frequency offsets and eigenvalue positions, the transmitter side encodes 4-bit information onto 16 kinds of different digital frequency offsets. Then, a sliding window-assisted eigenvalue position (SWA-EP) decoding technology is further proposed to substitute the classical channel equalization and carrier phase recovery processes, with the purpose of recovering the original information. The numerical and experimental results demonstrate that, compared with b-coefficient 16 quadrature amplitude modulation (QAM) scheme, Q-factor gains are 2.1 dB under 15 dB optical signal-to-noise ratio (OSNR) and 1.8 dB after 800 km fiber transmission, respectively. Moreover, its complexity is only 0.6% of the b-coefficient scheme. The DFO-loading scheme offers an effective and low-complexity way to mitigate ASE noise of DS-NFDM system.

A robust localization approach for Percutaneous Nephrolithotomy (PCNL): A single-center retrospective study.

BACKGROUND: Percutaneous Nephrolithotomy (PCNL) represents the gold standard treatment method for cases with large kidney stones. As a critical step in performing PCNL, the procedure of establishing a safe and accurate nephrostomy tract will dramatically impact the treatment quality of patients with large-sized kidney stones. OBJECTIVE: This work attempts to describe a new and improved process of establishing an accurate nephrostomy tract and clinically evaluate the effectiveness and safeness of this proposed methodology. METHODS: This work represents a retrospective single-center study carried out between August 2013 and November 2019. The collected samples consist of 937 patients who were operated on using PCNL coupled with our proposed procedure. Briefly, a preoperative B-ultrasonography was firstly performed to decide the puncture point in a simulated surgical position where was marked with ureteral catheter segments (2-3 cm). A computed tomography (CT) scan was followed to correct the anchor points in the simulated surgical position. After this, an accurate puncture operation was performed under the real-time guidance of intraoperative B ultrasound. RESULTS: Examining this study, 851 subjects with renal stones and 86 subjects with ureteropelvic junction stones were included for the PCNL operation project. All samples were grouped with Guy's grading system: grade I, II, III, and IV patients there were 0.00%, 42.69%, 51.01%, and 6.30%, respectively. Among these patients, the average age was 48.49 ± 10.80 years old, with a male to female ratio of around 1.73:1. CONCLUSIONS: This study showed that our developed method warrants an accurate and safe PCNL operation that involves the process of establishing the nephrostomy tract. Other advantageous attributes of this new PCNL process include negligible radiation exposure, lesser complications, and low failure rates. More importantly, this new localization approach is particularly attractive for hospitals that are new to the field of adopting PCNL considering its safeness, effectiveness, and learnability.

Assembly of silica rods into tunable branched living nanostructures mediated by coalescence of catalyst droplets.

Branched nanostructures with tunable arm numbers were prepared through the assembly of silica rods mediated by coalescence of catalyst droplets on the end of the rods. The formed primary branched colloids retain living characteristics similar to the original ones, that is, they can further assemble into multilevel and hierarchical branched structures.

[Treatment of humeral supracondylar fracture through small lateral incision].

OBJECTIVE: To explore the effect of treatment of humeral supracondylar fracture with Kirschner and tension band wire fixation through small lateral incision. METHODS: Fifty-eight patients of humeral supracondylar fractures included 42 males and 16 females with the average age of 9.4 years ranging from 3 to 65 years old. All patients were treated with Kirschner and tension band fixation through small lateral incision of 4 to 5 cm after reduction through lateral approach from the inter muscular space between the lateral of triceps brachii and the brachioradial muscle. Two Kirschner were insterted from the lateral condylars to humeral medial. Drill plumb on the humeral above fracture line distance 2 to 3 cm. A wire through bended on the lateral two Kirschners nails crossed in the shape of "8" figure. RESULTS: The fracture obtained accurately reduction and rigidly fixation. All patients were followed up for 1 to 5 years (mean 2.4 years). According to Flynn clinical evaluation, the results were excellent in 48 cases, good in 6,fair in 3 and poor in 1. CONCLUSION: This method has advantages of minimal trauma, easy manipulation, less operative time, early exercises and rapid recovery for the treatment of humeral supracondylar fracture.