Ultrafast polarization characterization with Mueller matrix based on optical time-stretch and spectral encoding.

High-speed optical polarization characterization is highly desirable for a wide range of applications, including remote sensing, telecommunication, and medical diagnosis. The utilization of the Mueller matrix provides a superior systematic and comprehensive approach to represent polarization attributes when matter interacts with optical beams. However, the current measurement speed of Mueller matrix is limited to only seconds or milliseconds. In this study, we present an ultrafast Mueller matrix polarimetry (MMP) technique based on optical time-stretch and spectral encoding that enables us to achieve an impressive temporal resolution of 4.83 nanoseconds for accurate Mueller matrix measurements. The unique feature of optical time-stretch technology enables continuous, ultrafast single-shot spectroscopy, resulting in a remarkable speed of up to 207 MHz for spectral encoding Mueller matrix measurement. We have employed an effective Mueller linear reconstruction algorithm based on the measured modulation matrix, accounting for all potential non-ideal effects of polarization components like retardance error and azimuth error. To ensure high precision, prior to the actual measurement, high-order dispersion induced by time-stretch requires adjustment through proper modulation matrix design. Upon such correction, both the results of static and rapid dynamic samples measurements exhibit exceptional accuracy with root-mean-square error (RMSE) approximately equal to 0.04 and 0.07 respectively. This presented ultrafast MMP provides a significant advance over preceding endeavors, enabling superior accuracy and increased speed concurrently.

Modified Y-V plasty based on MRU evaluation for iatrogenic bladder outlet obliteration: a multicentre experience in China.

PURPOSE: To compare the diagnostic ability of traditional radiographic urethrography and magnetic resonance urethrography (MRU) for iatrogenic bladder outlet obliteration (BOO), and explore the efficacy and complications of laparoscopic modified Y-V plasty for patients selected based on MRU evaluation. METHODS: 31 patients with obliteration segments ≤ 2 cm and no false passages or diverticula based on MRU evaluation from eight centers in China were included. Obliteration segments were measured preoperatively by MRU and conventional RUG/VCUG and compared with intra-operative measurements. Surgical effects were evaluated by uroflow rates, urethrography, or cystoscopy at 1, 3, 6, and 12 months post-operation and then every 12 months. Postoperative urinary continence was assessed by 24-h urine leakage (g/day). RESULTS: The results showed that MRU measured the length of obliteration more accurately than RUG/VCUG (MRU 0.91 ± 0.23 cm, RUG/VCUG 1.72 ± 1.08 cm, Actual length 0.96 ± 0.36 cm, p < 0.001), and clearly detected false passages and diverticula. Laparoscopic Y-V plasty was modified by incisions at 5 and 7 o'clock positions and double-layer suture with barbed sutures. All operations were successfully completed within a median time of 75 (62-192) minutes and without any complications. Urethral patency and urinary continence rates were 90.3% (28/31) and 87.1% (27/31), respectively. Three recurrences were cured by direct visual internal urethrotomy. Four patients had stress urinary incontinence after catheter removal 14 days post-operation, with urine leakage of 80-120 g/day, not relieved during follow-up. CONCLUSIONS: Laparoscopic modified Y-V plasty based on MRU evaluation is a promising approach for iatrogenic BOO, with a high patency rate and a low incontinence rate.

Urethral-sparing laparoscopic simple prostatectomy for the treatment of benign prostatic hyperplasia with asymptomatic urethral stricture after urethral stricture surgery.

OBJECTIVE: To evaluate the efficacy of urethral-sparing laparoscopic simple prostatectomy (US-LSP) for the treatment of large-volume (>80 ml) benign prostatic hyperplasia (BPH) with asymptomatic urethral stricture (urethral lumen > 16 Fr) after urethral stricture surgery. METHODS: We retrospectively analyzed clinical data of 39 large-volume BPH patients with asymptomatic urethral stricture after urethral stricture surgery who underwent US-LSP from January 2016 to October 2021. Postoperative follow-ups were scheduled at 1, 3, and 6 months. RESULTS: All patients affected by significant BPH-related lower urinary tract symptoms (LUTS) including 22 cases with asymptomatic anterior urethral stricture and 17 cases with asymptomatic posterior urethral stricture. Median operative time was 118 min (interquartile range [IQR]100-145). Median estimated blood loss was 224 ml (IQR: 190-255). 33 patients(84.6%) avoided continuous bladder irrigation. Postoperative complications occurred in 5 patients (12.8%), including 4 cases with Clavien-Dindo grade 1 and grade 2 and 1 case with grade 3a. During follow-up, US-LSP presented statistically significant improvements in LUTS compared to baseline (P < 0.05). A total of 25 patients had normal ejaculation preoperatively and 3 patients (12%) complained retrograde ejaculation postoperatively. Two patients (5.1%) reported stress urinary incontinence (SUI) and no patient reported aggravated urethral stricture during follow-up. CONCLUSIONS: US-LSP was safe and effective in treating large-volume BPH with asymptomatic urethral stricture after urethral stricture surgery. Meanwhile, US-LSP could reduce the risk of SUI in patients with asymptomatic posterior urethral stricture and maintain ejaculatory function in a high percentage of patients.

Remodeling the polymer-binding cavity to improve the efficacy of PBAT-degrading enzyme.

Poly(butylene adipate-co-terephthalate) (PBAT) is among the most widely applied synthetic polyesters that are utilized in the packaging and agricultural industries, but the accumulation of PBAT wastes has posed a great burden to ecosystems. Using renewable enzymes to decompose PBAT is an eco-friendly solution to tackle this problem. Recently, we demonstrated that cutinase is the most effective PBAT-degrading enzyme and that an engineered cutinase termed TfCut-DM could completely decompose PBAT film to terephthalate (TPA). Here, we report crystal structures of a variant of leaf compost cutinase in complex with soluble fragments of PBAT, including BTa and TaBTa. In the TaBTa complex, one TPA moiety was located at a polymer-binding site distal to the catalytic center that has never been experimentally validated. Intriguingly, the composition of the distal TPA-binding site shows higher diversity relative to the one proximal to the catalytic center in various cutinases. We thus modified the distal TPA-binding site of TfCut-DM and obtained variants that exhibit higher activity. Notably, the time needed to completely degrade the PBAT film to TPA was shortened to within 24 h by TfCut-DM Q132Y (5813 mol per mol protein). Taken together, the structural information regarding the substrate-binding behavior of PBAT-degrading enzymes could be useful guidance for direct enzyme engineering.

Unleashing the Power of Evolution in Xylanase Engineering: Investigating the Role of Distal Mutation Regulation.

The drive to enhance enzyme performance in industrial applications frequently clashes with the practical limitations of exhaustive experimental screening, underscoring the urgency for more refined and strategic methodologies in enzyme engineering. In this study, xylanase Xyl-1 was used as the model, coupling evolutionary insights with energy functions to obtain theoretical potential mutants, which were subsequently validated experimentally. We observed that mutations in the nonloop region primarily aimed at enhancing stability and also encountered selective pressure for activity. Notably, mutations in this region simultaneously boosted the Xyl-1 stability and activity, achieving a 65% success rate. Using a greedy strategy, mutant M4 was developed, achieving a 12 °C higher melting temperature and doubled activity. By integration of spectroscopy, crystallography, and quantum mechanics/molecular mechanics molecular dynamics, the mechanism behind the enhanced thermal stability of M4 was elucidated. It was determined that the activity differences between M4 and the wild type were primarily driven by dynamic factors influenced by distal mutations. In conclusion, the study emphasizes the pivotal role of evolution-based approaches in augmenting the stability and activity of the enzymes. It sheds light on the unique adaptive mechanisms employed by various structural regions of proteins and expands our understanding of the intricate relationship between distant mutations and enzyme dynamics.

Functional tailoring of a PET hydrolytic enzyme expressed in Pichia pastoris.

Using enzymes to hydrolyze and recycle poly(ethylene terephthalate) (PET) is an attractive eco-friendly approach to manage the ever-increasing PET wastes, while one major challenge to realize the commercial application of enzyme-based PET degradation is to establish large-scale production methods to produce PET hydrolytic enzyme. To achieve this goal, we exploited the industrial strain Pichia pastoris to express a PET hydrolytic enzyme from Caldimonas taiwanensis termed CtPL-DM. In contrast to the protein expressed in Escherichia coli, CtPL-DM expressed in P. pastoris is inactive in PET degradation. Structural analysis indicates that a putative N-glycosylation site N181 could restrain the conformational change of a substrate-binding Trp and hamper the enzyme action. We thus constructed N181A to remove the N-glycosylation and found that the PET hydrolytic activity of this variant was restored. The performance of N181A was further enhanced via molecular engineering. These results are of valuable in terms of PET hydrolytic enzyme production in industrial strains in the future.