Effect of tricalcium phosphate, hydroxyethyl methacrylate, and ethylene glycol dimethacrylate on the mechanical properties of acrylic bone cement

Abstract

The effects of the addition of tricalcium phosphate (TCP), hydroxyethyl methacrylate (HEMA), and ethylene glycol dimethacrylate (EGDMA) on the properties of standard surgical Simplex-P radiopaque bone cement have been investigated. The fracture surface after tensile test was studied by scanning electron microscopy. The influence of these components on the temperature rise during polymerization was investigated. It was found that the tensile strength, the bending strength, and the compressive strength decreased with increasing TCP content, whereas the inverse was observed for the Young's modulus. The tensile strength slightly increased with increasing HEMA content and then it levelled off when the HEMA content was higher than 15 wt.-%. It seemed that there were maximum tensile, bending and compressive strengths when 2 wt.-% EGDMA (in HEMA) was added. Polymerization occurred more rapidly when HEMA and EGDMA were added, whereas the inverse result was found with TCP. ZUSAMMENFASSUNG:Der EinfluB einer Beimischung von Tricalciumphosphat (TCP), Hydroxyethylmethacrylat (HEMA) und Ethylenglycoldimethacrylat (EGDMA) auf die Eigenschaften eines chirurgischen Knochenzements wurde untersucht. Die in Zugversuchen entstandenen Bruchflachen wurden mittels Rasterelektronenmikroskopie charakterisiert. Der EinfluB der Additive auf den Temperaturanstieg wahrend der Polymerisation wurde gepriift. Zug-, Biege-und Druckfestigkeit des ausgeharteten Zements nahmen mit zunehmendem TCP-Gehalt ab, der Elastizitatsmodul stieg dagegen an. Die Zugfestigkeit nahm mit steigendem HEMA-Gehalt geringfugig zu und blieb oberhalb 15 Gew.-% HEMA konstant. Zug-, Biege-und Druckfestigkeit zeigten bei einem EGDMA-Gehalt von 2 Gew.-% (in HEMA) ein Maximum.HEMA und EGDMA beschleunigten die Polymerisation, wogegen TCP retardierend wirkte.

Liquid chromatography of active principles in Sophora flavescens root

“…Many matrine-type alkaloids from S. flavescens root are relative polar, which has made reversed-phase HPLC a suitable method for their determination. The most popular reversed-phase columns for lupin alkaloids separation today are applied from silica-based bonded phase, and among those the C 18 -type bonded or amino-bonded phase is most frequently used (Table 4 [8,9,[38][39][40][41][42][43][44][45][46][47][48][49][50][51][52]). Matrine-type alkaloids from S. flavescens root were first isolated and reversed-phase HPLC separation by Ota et al [53].…”