Hardenability and Wear Resistance of Carburized to Hypereutectic Concentrations Steels

In this article the experimental data of the hardness and wear resistance of chrome-manganese steels 35H3G2F and 35HGF, which are cemented in a highly active paste-like carburizer and hardened at various temperatures, are presented. Cementation and high temperature carbonitriding of these steels leads to a high content of the carbide phase in the diffuse layers and an increase of hardness and wear resistance. The effect of carbides on the hardenability of diffuse layers are investigated. The hardening temperature ranges of these steels and the effect of alloying elements on hardness are established. The mechanism of the phase formation of the highest hardness structures is described. The carbides influence on the wear mechanism of cemented in various modes steels is studied.

A prospective randomized double-blind controlled trial to evaluate the efficacy of an analgesic epidural paste following lumbar decompressive surgery

Object. Pain control can often be improved by local (as opposed to systemic) application of analgesic and/or anesthetic medication. The purpose of this study was to evaluate the efficacy of a single-dose epidural analgesic “paste” in the control of postoperative pain in patients who have undergone lumbar decompressive surgery. Methods. Sixty patients undergoing routine elective lumbar decompressive surgery were randomized in a double-blind fashion to one of two groups: those receiving active paste or placebo paste. The paste was applied to the exposed dura at the time of surgery, just prior to wound closure. Patients received follow-up care in the hospital and at home for 3 months postsurgery. Several outcome measures were studied to ascertain differences in pain control and to ensure comparability between groups. Patients who received active paste demonstrated significantly lower pain scores compared with those who received placebo paste for up to 6 weeks postoperatively. General health perception indexed by the Short Form 36 was also significantly better in patients who received active paste for up to 6 weeks. In-hospital and outpatient oral narcotic consumption was significantly lower in the active paste-treated group. Inpatient straight leg raising scores were improved in those patients who received active compared with control paste. Conclusions. Application of an analgesic paste directly to the epidural space during lumbar decompressive surgery significantly improves postoperative pain control, reduces prescribed analgesic drug consumption, and improves overall health perception for up to 6 weeks following surgery. The authors conclude that this postoperative pain control strategy is both effective and safe and may provide a new standard of pain management in patients undergoing lumbar discectomy or laminectomy.