The role of sulphur in the synthesis of carbon nanotubes by chemical vapour deposition at high temperatures.

Sulphur has been recognised as a growth promoter for carbon fibres and carbon nanotubes for over 30 years. Moreover, the Fe-C-S system, in particular, has been extensively studied for more than half a century in the fields of steelmaking and cast iron. In the present work we examine the role of sulphur in the iron-catalysed growth of carbon nanotubes during the process of direct spinning of fibres from the gas phase. A detailed microstructural characterisation of the reaction products was conducted by high resolution TEM and EELS composition mapping on a dedicated FEG STEM (VG HB 501) equipped with Cs aberration correctors. Our results agree with previous works in classical metallurgy, indicating that sulphur forms a layer on the surface of the catalyst particles that plays a role in encouraging nanotube growth by surface diffusion.

Arthroscopic anterior cruciate ligament reconstruction using a hamstring graft with interference screw fixation.

BACKGROUND AND AIMS: This study assessed the clinical and radiographic results 3 to 8 years after an arthroscopic ACL reconstruction using a hamstring graft with interference screw fixation on femoral and tibial sites. MATERIAL AND METHODS: Seventy-six of 100 patients, who underwent an arthroscopic ACL reconstruction, could be re-examined with a mean follow-up of 5 years. RESULTS: The mean Tegner activity score was 4 (scale: 0 to 10) before surgery, and 5 at the follow-up. Fifty-four patients (78%) achieved a satisfactory result in the IKDC rating. The mean Lysholm score was 85 (scale: 0 to 100), the score being better in patients without meniscal resection than those with (P = 0.04). The mean side-to-side difference in anterior-posterior knee laxity was 1.8 mm, and 62 patients (90%) had good stability. Sixty-four patients (93%) had normal range of motion of the knee. Twelve patients (46%) with meniscal resection had osteoarthritic changes, compared with only 8 of those (20%) without meniscal resection (P = 0.03). CONCLUSIONS: This medium-term follow-up study showed that good stability and function and normal range of motion of the knee can be achieved in majority of the patients who have undergone an ACL reconstruction with a hamstring graft and interference screw fixation.

Muscle strength evaluations after ACL reconstruction.

The quadriceps and hamstring muscle strengths of 16 patients operated using a bone-patellar tendon-bone (BTB) autograft and 32 patients operated using a quadruple hamstring autograft for an arthroscopic anterior cruciate ligament (ACL) reconstruction were analyzed 4- to 7-years postoperatively. Standardized isokinetic testing, a clinical evaluation and instrumented assessment of knee laxity were done. The findings showed no significant strength deficits between the patients in the BTB and Hamstring groups and the deficits were, in general, small. The quadriceps and hamstring muscle strengths were better in patients with a longer than shorter follow-up and stable knees had less knee flexion torque deficit than unstable knees. Strength deficit was associated with lower Lysholm knee scores. The findings of this study showed that the muscle strengths of the operated limb had a positive association with the functional outcome of the knee in the long-term and support the use of active rehabilitation after ACL reconstruction.