Effects of Pre- and Post-Carburizing Surface Modification on the Tribological and Adhesion Properties of Heat-Resistant KHR 45A Steel for Cracking Tubes.

In this study, the effects of ultrasonic nanocrystal surface modification (UNSM) technology on the tribological properties and scratch-induced adhesion behavior of a heat-resistant KHR 45A steel cracking tube, which is used for the pyrolysis process, were investigated. The main objective of this study is to investigate the effects of pre- and post-carburizing UNSM treatment on the tribological and adhesion performances of carburized domestic KHR 45A (A) steel and to compare the results with the existing carburized Kubota-made KHR 45A steel (B). A carburizing process was carried out on the polished and UNSM-treated KHR 45A steel substrates, which were cut out from the cracking tube, at 300 °C heat exposure for 300 h. The thickness of the carburizing layer was about 10 µm. UNSM technology was applied as pre- and post-carburizing surface treatment; both reduced the friction coefficient and wear rate compared to that of the carburized KHR 45A steel substrate. It was also found that the application of UNSM technology increased the critical load, which implies the improvement of adhesion behavior between the carburizing layer and the KHR steel substrate. The application of UNSM technology as pre- and post-carburizing surface treatment could help replace carburized Kubota-made KHR 45A steel (B) thanks to the improved tribological performance, enhanced scratch resistance, load bearing capacity, and adhesion of domestic KHR 45A (A) steel.

Safety of total laparoscopic hysterectomy in patients with prior cesarean section.

AIM: Patients who have undergone a cesarean section (CS) prior to hysterectomy are at a higher perioperative risk of complications. The purpose of this study was to evaluate the safety of total laparoscopic hysterectomy (TLH) in patients with prior CS. METHODS: We enrolled 482 patients treated with TLH. Surgical outcomes including major complications were compared between patients without prior CS (no CS group; n = 324) and patients with prior CS (prior CS group; n = 158). Major complications included vaginal cuff dehiscence, and bowel, bladder, ureter and great vessel injuries. RESULTS: Major complications, uterus weight, hospital day, unscheduled transfusion and conversion to laparotomy did not differ significantly between groups. One bowel injury occurred in the no CS group. Two vaginal cuff dehiscences and one bladder injury occurred in the prior CS group. There were no ureter or great vessel injuries. Operation duration was longer (P = 0.030) in the prior CS group, but only seven minutes longer than the no CS group. The Foley catheter indwelling day was also significantly longer (P < 0.001) in the prior CS group, but did not last one day. The number of prior CS had no effect on the major complication rate. After treatment of major complications, no long-term sequelae were observed. CONCLUSIONS: TLH in patients with a history of CS can be performed safely as such history had no effect on the major complication rate. Complications were rare and were treated successfully.

Refractive predictability of partial coherence interferometry and factors that can affect it.

PURPOSE: To evaluate the refractive predictability of a partial coherence interferometry (PCI) biometry device (IOL Master) for cataract surgery and to investigate factors that may affect it. METHODS: Retrospective review of 209 eyes from 151 patients that had undergone preoperative PCI biometry and an uneventful phacoemulsification cataract surgery with posterior chamber intraocular lens (IOL) implantation was conducted. Prediction error defined as the intended refraction minus the postoperative refraction in spherical equivalent (SE) and the absolute error were analyzed according to IOL calculation formulas, patient characteristics, preoperative visual acuity (VA) and refraction, posterior subcapsular cataract (PSC), signal-to-noise ratio (SNR), and axial length (AL). RESULTS: The overall refractive predictability of the PCI device was good. Generally, the SRK/T formula performed better than the SRK-II formula. Refractive predictability was slightly worse in eyes with >or=+2.0 diopters (D) of preoperative SE (with both SRK-II and SRK/T) and in eyes with an ALor=+2.0D was related to a significantly greater hyperopic shift in postoperative refraction. With proper verification of measured data and a suitable IOL calculation formula, good refractive predictability is expected from PCI biometry regardless of patient characteristics, preoperative VA, SNR, PSC, and AL.