The aim of the study was to assess the value of D-dimer as an event predicitor for deep vein thrombosis (DVT) in patients given low molecular weight heparin (LMWH) after total hip arthroplasty (THA). Plasma D-dimer levels were obtained preoperatively and at days 1, 3, and 7 postoperatively in 83 consecutive patients undergoing THA treated with nadroparin prophylaxis plus intermittent pneumatic compression. Unilateral ascending venography was performed at postoperative day 7 or 8. There was a significant difference between the D-dimer levels in the DVT group (28 patients) and non-DVT group (55 patients) on each day (P<0.01). ROC analysis showed the AUC on postoperative days 1, 3 and 7 was 0.706, 0.712 and 0.772 respectively. The D-dimer concentration on postoperative day 1, day 3 or day 7 is of moderate predicting value of DVT in patients undergoing THA, treated with nadroparin prophylaxis plus intermittent pneumatic compression.

In order to meet the demand for high strength of Al alloy in aerospace, automobile, shipbuilding and other fields, the effects of aging treatment on the microstructure and properties of Al-4.5Cu-0.8Mg alloy were systematically studied. The results show that the main strengthening phase in the microstructure of the alloy after aging was θ’ And S’ phase, the comprehensive mechanical properties of single-stage aging after aging at 165 °C for 12h was better. In the alloy aged at 185 °C for 12 hours, the strengthening phase was coarsen obviously, the tensile strength and yield strength was decrease greatly and showed obvious over aging characteristics. The comprehensive mechanical properties of two-stage aging at 105 °C / 12h + 165 °C / 5h was the best. The tensile strength, yield strength, elongation and hardness are 543 MPa and 374 MPa, 17.5% and 170.6 HV respectively.