Are Oxinium Femoral Heads Superior to Alternative Bearing Surface Materials? A Systematic Review

Oxidized zirconium (OxZr) femoral heads were developed to emulate the superior wear and scratch properties of ceramics while eliminating their unwanted tendency for brittle fracturing. Studies using OxZr have demonstrated reduced linear and volumetric wear of polyethylene (PE) liners when compared with cobalt chrome, ceramic, and steel femoral heads. The purpose of this systematic review was to determine the difference in revision rates, radiologically determined linear wear rates, and patient-reported outcomes among OxZr and alternative bearing materials. Following the Preferred Reporting Items for Systematic Review and Meta-Analysis protocols, a systematic review of published literature through April 24, 2018 was conducted. Among the 862 cases included at a mean weighted follow-up of 4.78 years, the revision THA rate and patient-reported outcomes were similar among OxZr and alternative bearing materials. One of the five studies demonstrated significantly lower linear wear rates in the OxZr group when paired with ultrahigh molecular-weight PE (OxZr 0.03 mm/y vs. stainless-steel 0.11 mm/y; p < 0.001) and when paired with highly-crosslinked PE (OxZr 0.02 mm/y vs. stainless-steel 0.04 mm/y; p < 0.001). The remaining four studies found no difference in linear wear rates. OxZr demonstrated similar outcome to that of modern-day ceramic and metal femoral heads for short- and mid-term revision surgery rates and patient-reported outcomes. Longer term studies are needed to evaluate if any long-term wear advantages are seen with the use of OxZr femoral heads and if the use of OxZr is cost effective compared with ceramic or metal alternatives. The level of evidence of the study is level II, systematic review.

Evaluation of herbicides for hair fescue (Festuca filiformis) management and potential seedbank reduction in lowbush blueberry

Hair fescue is a widespread, seed-limited perennial grass in lowbush blueberry fields. Growers rely on pronamide, an expensive and difficult herbicide to use, for hair fescue management. Recent herbicide registrations provide opportunity to reduce pronamide use, though effects of these herbicides on hair fescue suppression and seedbank reduction are not well understood. The objectives of this research were to determine (1) the effects of herbicides currently registered in lowbush blueberry on suppression of hair fescue tufts and (2) whether suppression of hair fescue with these herbicides reduces hair fescue seedbanks. Pronamide gave the most consistent reductions in flowering tuft density, though applications after both autumn pruning and autumn of the nonbearing year were required to reduce the hair fescue seedbank by >60% across sites. Nonbearing-year hexazinone applications did not control hair fescue or reduce the seedbank. Nonbearing-year terbacil applications reduced flowering tuft density, but hair fescue recovered in the bearing year, and the seedbank was not reduced. Glufosinate applications following autumn pruning or in the spring of the nonbearing year did not suppress hair fescue or reduce the seedbank. Spring nonbearing-year foramsulfuron applications, alone or after autumn or spring glufosinate applications, reduced hair fescue flowering tuft density, but hair fescue recovered in the bearing year, and the seedbank was not reduced. In contrast, autumn and spring glufosinate applications followed by spring nonbearing-year foramsulfuron applications, when combined with autumn nonbearing-year pronamide applications, reduced flowering tuft density in both the nonbearing and bearing years and reduced the hair fescue seedbank by 58% to 83% across sites. Results indicate that hair fescue seedbanks can be reduced in lowbush blueberry fields and that a reduction in pronamide use will require alternative bearing-year treatments to prevent tuft recovery and seed production.

Lagerungsalternativen durch Einsatz von Synchronreluktanztechnologie in Motorspindeln*/Alternative bearing concept by using synchronous reluctance drives for main spindle drives

Die Energieeffizienz von modernen Motorspindelsystemen wirkt sich direkt auf deren thermisches Verhalten aus. 60 % der in Werkzeugmaschinen verbauten Motorspindeln basieren auf asynchroner Technologie. Neben ihrem robusten, kostengünstigen und einfachen Aufbau bringen sie auch einige Nachteile mit sich. Diese sind vor allem in ihrem thermischen Verhalten begründet. Durch die starke Rotorerwärmung müssen aufwendige Lagerungen vorgesehen werden. Dieser Problematik kann mit dem Einsatz eines alternativen Antriebstyps in Motorspindeln – dem Synchronreluktanzantrieb – begegnet werden. Durch die systembedingt geringen thermischen Verluste lassen sich einfachere Lagerungsstrategien aufbauen. &nbsp; The energy efficiency of modern motor spindle systems has a direct impact on their thermal behavior. 60 % of the installed motor spindles are based on asynchronous drives. In addition to its robust, low cost and simple construction, they also have some disadvantages. These are mainly caused by their thermal behavior. Due to the strong rotor heating an elaborate bearing concept has to be build. This problem can be addressed through the use of a new class of motor spindles drive, the synchronous reluctance machine. Due to the low-loss operating behavior more simple bearing concepts can be applicated.