Low frequency electromagnetic casting （LFEC） process with the application of an induction coil outside the conventional direct chill （DC） casting mould was used to prepare the flat ingot of 2524 alloy and the effe...Low frequency electromagnetic casting （LFEC） process with the application of an induction coil outside the conventional direct chill （DC） casting mould was used to prepare the flat ingot of 2524 alloy and the effect of electromagnetic field on the microstructure and macrosegregation of this alloy was systematically studied. The results show that the fiat ingot prepared by the LFEC process has a finer and more uniform as-cast microstructure and the grain morphology is transformed from dendrite and rosette-like to equiaxed structure. The LFEC process also shows a significant effect on macrosegregation, and with the application of electromagnetic field during casting process, the segregation in the centre of the ingot is obviously reduced. The mechanism of these effects was also discussed.展开更多
AM60B magnesium alloy was refined by MgCO3 and its microstmcturat evolution was investigated during partial remelting. The results indicate that MgCO3 is an effective grain refiner for AM60B alloy and can decrease the...AM60B magnesium alloy was refined by MgCO3 and its microstmcturat evolution was investigated during partial remelting. The results indicate that MgCO3 is an effective grain refiner for AM60B alloy and can decrease the grain size from 329 pm of the unrefined alloy to 69 μm. A semisolid microstructure with small and spheroidal primary particles can be obtained after being partially remelted. The microstructure evolution can be divided into four steps： the initial rapid coarsening, structure separation, spheroidization and final coarsening. Correspondingly, these four steps result from the phase transformations of β→α, α＋β→L and α→L, α→L and two reverse reactions of α→L and L→α, respectively. One spheroidal primary particle in the semisolid microstmcture usually originates one dendrite in the as-cast microstructure. The variation of primary particle size with holding time does not obey the LSW law, Dt^3-Do^3=Kt, after the semisolid system is in its solid-liquid equilibrium state. Longer heating duration makes the primary particles more globular, but it makes their size larger at the same time.展开更多
AIM: To determine the prevalence of increased intraepithelial lymphocytes, using immunohistochemistry in patients with normal colonoscopy and near normal biopsy. METHODS: We retrospectively reviewed all non-malignant ...AIM: To determine the prevalence of increased intraepithelial lymphocytes, using immunohistochemistry in patients with normal colonoscopy and near normal biopsy. METHODS: We retrospectively reviewed all non-malignant colon mucosal biopsies between 2005 and 2007, reported as normal, chronic inflammation or melanosis coli in patients who were undergoing routine colonoscopy. Immunohistochemistry using CD3 was performed on all mucosal biopsies and an intraepithelial lymphocyte count (IEL) was determined. Cases with an IEL count of ≥ 20 IELs per 100 surface epithelial cells were correlated with demographic, clinical and follow-up data. A further subgroup was evaluated for lymphocytic colitis.RESULTS: Twenty (8.3%) of 241 cases revealed an IEL count ≥ 20. Six (2.5%) patients were identified as having lymphocytic colitis (P < 0.001), of whom, five were missed on initial evaluation (P = 0.01). Four of these five patients were labeled with diarrhea-predominant irritable bowel syndrome (IBS). On follow-up, three of the remaining 20 cases were diagnosed with malignancy (renal cell carcinoma and myelodysplastic syndrome) and one had an unknown primary tumor with multiple liver metastases. Two cases of collagenous colitis with an IEL count < 10 were included in this study. Increased IELs were not confined to patients with diarrhea as a primary presenting symptom, but were also present in patients with abdominal pain (n = 7), constipation (n = 3) and loss of weight (n = 1). CONCLUSION: Immunohistochemistry using CD3 is of value in identifying and quantifying IELs for the presence of microscopic colitis in patients with diarrheapredominant IBS.展开更多
基金Projects(51104043,51374067)supported by the National Natural Science Foundation of ChinaProject(2012CB619506)supported by the National Basic Research Program of ChinaProject(N120409002)supported by the Fundamental Research Funds for the Central Universities,China
文摘Low frequency electromagnetic casting （LFEC） process with the application of an induction coil outside the conventional direct chill （DC） casting mould was used to prepare the flat ingot of 2524 alloy and the effect of electromagnetic field on the microstructure and macrosegregation of this alloy was systematically studied. The results show that the fiat ingot prepared by the LFEC process has a finer and more uniform as-cast microstructure and the grain morphology is transformed from dendrite and rosette-like to equiaxed structure. The LFEC process also shows a significant effect on macrosegregation, and with the application of electromagnetic field during casting process, the segregation in the centre of the ingot is obviously reduced. The mechanism of these effects was also discussed.
基金Project(G2007CB613706) supported by the National Basic Research Program of China
文摘AM60B magnesium alloy was refined by MgCO3 and its microstmcturat evolution was investigated during partial remelting. The results indicate that MgCO3 is an effective grain refiner for AM60B alloy and can decrease the grain size from 329 pm of the unrefined alloy to 69 μm. A semisolid microstructure with small and spheroidal primary particles can be obtained after being partially remelted. The microstructure evolution can be divided into four steps： the initial rapid coarsening, structure separation, spheroidization and final coarsening. Correspondingly, these four steps result from the phase transformations of β→α, α＋β→L and α→L, α→L and two reverse reactions of α→L and L→α, respectively. One spheroidal primary particle in the semisolid microstmcture usually originates one dendrite in the as-cast microstructure. The variation of primary particle size with holding time does not obey the LSW law, Dt^3-Do^3=Kt, after the semisolid system is in its solid-liquid equilibrium state. Longer heating duration makes the primary particles more globular, but it makes their size larger at the same time.
基金Supported by National Health Laboratory Service ResearchFund, GRANT004_94023 (to Mohamed N)
文摘AIM: To determine the prevalence of increased intraepithelial lymphocytes, using immunohistochemistry in patients with normal colonoscopy and near normal biopsy. METHODS: We retrospectively reviewed all non-malignant colon mucosal biopsies between 2005 and 2007, reported as normal, chronic inflammation or melanosis coli in patients who were undergoing routine colonoscopy. Immunohistochemistry using CD3 was performed on all mucosal biopsies and an intraepithelial lymphocyte count (IEL) was determined. Cases with an IEL count of ≥ 20 IELs per 100 surface epithelial cells were correlated with demographic, clinical and follow-up data. A further subgroup was evaluated for lymphocytic colitis.RESULTS: Twenty (8.3%) of 241 cases revealed an IEL count ≥ 20. Six (2.5%) patients were identified as having lymphocytic colitis (P < 0.001), of whom, five were missed on initial evaluation (P = 0.01). Four of these five patients were labeled with diarrhea-predominant irritable bowel syndrome (IBS). On follow-up, three of the remaining 20 cases were diagnosed with malignancy (renal cell carcinoma and myelodysplastic syndrome) and one had an unknown primary tumor with multiple liver metastases. Two cases of collagenous colitis with an IEL count < 10 were included in this study. Increased IELs were not confined to patients with diarrhea as a primary presenting symptom, but were also present in patients with abdominal pain (n = 7), constipation (n = 3) and loss of weight (n = 1). CONCLUSION: Immunohistochemistry using CD3 is of value in identifying and quantifying IELs for the presence of microscopic colitis in patients with diarrheapredominant IBS.
