A low-alloy gray cast iron containing hard carbide-forming elements, such as vanadium and chromium, was cast by sand mould casting. Its wear resistance was compared with that of an untreated gray cast iron. Three diff...A low-alloy gray cast iron containing hard carbide-forming elements, such as vanadium and chromium, was cast by sand mould casting. Its wear resistance was compared with that of an untreated gray cast iron. Three different loading conditions were tested under a con- stant speed. It was observed that this alloy could reduce the wear loss of standard gray cast iron by up to 89%, which was much greater than what was achieved in previous reports. Scanning electron microscopy （SEM） was used to determine the predominant wear mechanism of both the alloys. In a mild wear regime, the oxidative mechanism was predominant; however, in a severe wear regime, this mechanism was not predominant and the adhesive mechanism was involved. EDX analysis was conducted to evaluate the quantitative amounts of elements in the tribochemical films formed on the wear tracks.展开更多
Background and objective: The aim of this study was to evaluate the association between dietary intake and bone mineral density in children with juvenile idiopathic arthritis (JIA). Methods: A cross-sectional study ca...Background and objective: The aim of this study was to evaluate the association between dietary intake and bone mineral density in children with juvenile idiopathic arthritis (JIA). Methods: A cross-sectional study carried out in Morocco between May 2010 and June 2011, covering out patients with JIA. The characteristics of patients were collected. The nutritional status was assessed by a food questionnaire including data of food intake during 7 consecutive days using 24-hour dietary recall. Food intake was quantified using the software Bilnut (Bilnut version 2.01, 1991). Bone mineral density (BMD in g/cm2) was measured by DXA method (X-ray absorptiometry) on a Lunar Prodigy. Results: The study consisted of 33 patients with JIA (4 - 16 years old). The median age of patients was 10.4 ± 4.3 years. Median disease duration was 2 (1 - 4.5) years. The group of patients with low dietary intake of proteins was associated with low BMD (p = 0.03). Low BMD was related with low intake of magnesium (p = 0.007) and vitamin C (p = 0.04) in children aged between 4 and 9 years. Low intake of vitamin E and folate was associated with high BMD in the other range of children (p < 0.001). Conclusion: This study suggests that low intake of protein and of some micronutrients (magnesium, vitamin C, vitamin E and folate) influence bone mass in children with JIA. Prospective studies with a larger number of patients seem to be necessary in order to confirm our findings.展开更多
文摘A low-alloy gray cast iron containing hard carbide-forming elements, such as vanadium and chromium, was cast by sand mould casting. Its wear resistance was compared with that of an untreated gray cast iron. Three different loading conditions were tested under a con- stant speed. It was observed that this alloy could reduce the wear loss of standard gray cast iron by up to 89%, which was much greater than what was achieved in previous reports. Scanning electron microscopy （SEM） was used to determine the predominant wear mechanism of both the alloys. In a mild wear regime, the oxidative mechanism was predominant; however, in a severe wear regime, this mechanism was not predominant and the adhesive mechanism was involved. EDX analysis was conducted to evaluate the quantitative amounts of elements in the tribochemical films formed on the wear tracks.
文摘Background and objective: The aim of this study was to evaluate the association between dietary intake and bone mineral density in children with juvenile idiopathic arthritis (JIA). Methods: A cross-sectional study carried out in Morocco between May 2010 and June 2011, covering out patients with JIA. The characteristics of patients were collected. The nutritional status was assessed by a food questionnaire including data of food intake during 7 consecutive days using 24-hour dietary recall. Food intake was quantified using the software Bilnut (Bilnut version 2.01, 1991). Bone mineral density (BMD in g/cm2) was measured by DXA method (X-ray absorptiometry) on a Lunar Prodigy. Results: The study consisted of 33 patients with JIA (4 - 16 years old). The median age of patients was 10.4 ± 4.3 years. Median disease duration was 2 (1 - 4.5) years. The group of patients with low dietary intake of proteins was associated with low BMD (p = 0.03). Low BMD was related with low intake of magnesium (p = 0.007) and vitamin C (p = 0.04) in children aged between 4 and 9 years. Low intake of vitamin E and folate was associated with high BMD in the other range of children (p < 0.001). Conclusion: This study suggests that low intake of protein and of some micronutrients (magnesium, vitamin C, vitamin E and folate) influence bone mass in children with JIA. Prospective studies with a larger number of patients seem to be necessary in order to confirm our findings.
