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AIM:To compare the differences of ocular biometric parameters of age-related cataract between Tibetan and Han ethnic groups, and to analyze the distribution characteristics of ocular biometric parameters in Tibetan cataract patients.METHODS:Retrospective cohort study. A total of 661 patients(1 030 eyes)with age-related cataract confirmed in the hospital between January 2019 and December 2020 were enrolled. The parameters of axial length, anterior chamber depth, keratometry, corneal astigmatism and astigmatic axis were measured by IOL Master 500 in 483 cases(739 eyes)of Tibetan age-related cataract patients and 178 cases(291 eyes)of Han patients.RESULTS:The axial length, anterior chamber depth and corneal astigmatism of the Tibetan patients with age-related cataract were 23.33(22.81, 23.86)mm, 3.04(2.79, 3.30)mm and 0.73(0.47, 1.07)D. The mean keratometry was 43.89±1.35 D. The results indicated that Tibetan cataract patients had shorter axial lengths and smaller keratometry compared to Han patients(all P

Objective To compare the analgesic effect and postoperative recovery quality of ultrasound-guided superficial and deep injection to superior costal transverse ligament (SCTL) for local anesthetics in thoracic paravertebral block (TPVB) combined with patient-controlled intravenous analgesia (PCIA) for postoperative analgesia in patients undergoing thoracoscopic surgery. Methods A total of 106 patients undergoing elective thoracoscopic surgery in the thoracic surgery department of our hospital from May 2021 to September 2021 were eligible for inclusion. They were randomly divided into SCTL superficial block group (Group S) and SCTL deep block group (Group T). Routine anesthesia induction and maintenance were performed in the both groups. After extubation, TPVB was operated under the guidance of ultrasound, and corresponding analgesic agent was injected into the superficial or deep surface of SCTL for local anesthetics, with 20 mL of 0.375% ropivacaine hydrochloride for single-point TPVB on the affected side, and PCIA was given at the same time. The positioning time and puncture time of ultrasonic image were recorded, the distance from the tip of ultrasonic image needle to pleura was measured, and the pleural depression and puncture related complications of ultrasonic image were observed. Visual analogue score (VAS) in resting and exercise (cough) states was evaluated at 5, 10, 20 and 30 min, and 4, 12 and 24 h (T0~6) after block. The use of analgesic pump within 24 h after operation was observed in terms of sufentanil dosage, first compression time, effective compression times, and actual compression times. QOR-40 was employed to investigate the quality of recovery before and 24 h after operation. Results Group S had significantly shorter puncture time (P < 0.05) and longer distance from the tip of the needle to the pleura on ultrasound image when compared with Group T (P < 0.05). Pleural depression could be observed in ultrasound image of 15 cases in Group S and of 51 cases in Group T (P < 0.05). There was 1 case of epidural block in Group T. The VAS score at T6 in exercise (cough) state was obviously higher in Group S than Group T (P < 0.05). But, because the scores in both groups belonged to the range of mild pain score, no clinical difference was identified between the 2 groups. There were no statistical differences in the other VAS scores in resting and exercise (cough) states, time of image positioning under ultrasound guidance, and use of analgesic pump within 24 h after operation, and QOR-40 scores before and 24 h after operation between the 2 groups. Conclusion Both ultrasound-guided superficial and deep injection of analgesic drugs into SCTL for TPVB can provide effective postoperative analgesia and equivalent postoperative recovery quality for patients after thoracoscopic surgery. SCTL can be used as injection reference for ultrasound guidance. But the superficial injection of SCTL is safer, easier and simpler in operation.

Here, a transition technique for converting signals from rectangular waveguide to coupled microstrip lines (CML) is presented, which provides a solution for differential antenna array feeding of automotive radar. The key to the proposed transition structure is to connect the coupling patches together with a short‐bridge structure, thus forming a quasi‐loop structure. Through the short bridge, the radiation efficiency of the antenna is greatly enhanced, and the mode conversion from TE10 of rectangle waveguide to differential mode of coupled microstrip line is realized effectively under the extremely compact size. Finally, the designed transition structure is manufactured and measured. The experimental results show that the back‐to‐back insertion loss is lower than 0.65 dB and the return loss is higher than 16.8 dB in the W‐band (75–110 GHz), which is the best performance and the simplest design among the relevant transition transitions reported so far. [ABSTRACT FROM AUTHOR]

This paper proposed an accurate series resistance model tailored for Schottky diode‐based terahertz multipliers. Compared to the conventional electrothermal model (E‐T model) only considering thermal effects, this model comprehensively accounts for both thermal and frequency effects of the series resistor components, including the temperature‐dependent epilayer resistance (Repi) and the temperature‐frequency‐dependent spreading resistance (Rspreading). The evaluation of thermal effects relies on steady‐state thermal simulation and the corresponding electrothermal model. Notably, the frequency‐dependent spreading resistance part is derived from the fitting conductivity of doped buffer layers and extracted by auxiliary three‐dimensional electromagnetic simulations. Based on this model, a balanced 225–300 GHz frequency tripler with AlN substrate has been designed and manufactured. By introducing this model, a significant improvement in the consistency between simulated and measured results has been achieved compared to the single E‐T model, regardless of whether the input power is low (80 mW) or high (160 mW). [ABSTRACT FROM AUTHOR]