目的探讨利用能谱CT物质分离技术评价冠状动脉钙化斑块狭窄率的准确性。方法收集行冠状动脉CT能谱成像的86例钙化斑块患者的图像,使用物质分离软件评价钙化斑块的狭窄程度,以冠状动脉造影为金标准进行对比;根据对比结果符合与否分成2组...目的探讨利用能谱CT物质分离技术评价冠状动脉钙化斑块狭窄率的准确性。方法收集行冠状动脉CT能谱成像的86例钙化斑块患者的图像,使用物质分离软件评价钙化斑块的狭窄程度,以冠状动脉造影为金标准进行对比;根据对比结果符合与否分成2组,比较2组之间在图像质量上的差异;根据钙化斑块所在冠状动脉节段管腔直径分为2~mm、3~mm及≥4 mm 3组,比较3组在符合程度上的差异。结果能谱CT扫描共检出256处钙化斑块。利用物质分离技术诊断0、<50%、≥50%和≥70%狭窄的灵敏度分别为88.89%、88.04%、83.08%、75.93%;特异度分别为97.16%、90.24%、92.15%、98.51%。2组在CT值、信躁比(SNR)上的差异有统计学意义,在SD上的差异无统计学意义。钙化斑块所在冠状动脉节段管腔大小影响狭窄率的判断,管腔越大,符合率越高。结论能谱CT物质分离技术评价冠状动脉钙化斑块狭窄率具有较高的准确性,图像质量和钙化斑块所在冠脉节段管腔大小对准确性的影响较大。展开更多
Due to the environmental policies and economic reasons,the water used in some flotation operations of complex sulfide ores is recirculated,causing the ion concentration of some species to increase over time,affecting ...Due to the environmental policies and economic reasons,the water used in some flotation operations of complex sulfide ores is recirculated,causing the ion concentration of some species to increase over time,affecting the flotation of the minerals of interest.In this work,an experimental and thermodynamic analysis of the synthetic solutions was presented with a high content of calcium and sulfate ions.The study focused on evaluating the use of two aluminum compounds for the precipitation of Ca^(2+)and SO_(4)^(2−)in the form of ettringite.The amorphous aluminum hydroxide was found to be more efficient than the crystalline one,giving rise to 83%calcium and 91%sulfate removal.The XRD analysis of the solids showed the main reaction product of ettringite,accompanied by small amounts of calcite,due to the absorption of atmospheric carbon dioxide.The final solution after the chemical treatment showed residual calcium and sulfate concentrations below 200 mg/L.Finally,the kinetics of calcium removal appeared to correspond to a second order reaction with respect to calcium concentration,with an apparent activation energy of 53.48 kJ/mol,which may suggest that the ettringite precipitation process is governed by the chemical reaction.展开更多
An acid sulfate soil sample was successively extracted with deionized water, 1 mol L-1 KCl and 0.000 5 mol L-l Ca(OH)2 solutions. The results showed that only very small amounts of acidity were extracted by deionized ...An acid sulfate soil sample was successively extracted with deionized water, 1 mol L-1 KCl and 0.000 5 mol L-l Ca(OH)2 solutions. The results showed that only very small amounts of acidity were extracted by deionized water, possibly through slow jarosite hydrolysis. Acid release through jarosite hydrolysis was greatly enhanced by Ca(OH)2 extraction at the expense of the added OH- being neutralized by the acid released. Successive extraction of the sample with KCl removed the largest amounts of acidity from the sample. However, it is likely that the major form of acidity released by KCl extraction was exchangeable acidity. The results also show the occurrence of low or non charged Al and Fe species in water and Ca(OH)2 extracts after first a few extractions. It appears that such a phenomenon was related to a decreasing EC value with increasing number of extractions.展开更多
In the perifused fura-2 loaded exocrine pancreatic acinar cell line AR4-2J pulses of high potassium induced repetitive increases in intracellular calcium. Attached cells when stimulated with high potassium secreted la...In the perifused fura-2 loaded exocrine pancreatic acinar cell line AR4-2J pulses of high potassium induced repetitive increases in intracellular calcium. Attached cells when stimulated with high potassium secreted large amount of amylase. High potassium-induced secretion was dependent both on the concentration of potassium and duration of stimulation. High potassium induced increases in intracellular calcium were inhibited by voltage-dependent calcium channel antagonists with an order of potency as follows: nifedipine > ω-agatoxin IVA > ω-conotoxin GVIA. In contrast, the L-type calcium channel antagonist nifedipine almost completely inhibited potassium-induced amylase secretion, whereas the N-type channel antagonist ω-conotoxin GVIA was without effect. The P-type channel antagonist ω-agatoxin IVA had a small inhibitory effect, but this inhibition was not significant at the level of amylase secretion. In conclusion, the AR4-2J cell line possesses different voltage-dependent calcium channels (L, P,N) with the L-type predominantly involved in depolarization induced amylase secretion.展开更多
Calcineurin dephosphorylates multiple serine residues near the N terminus of NFAT proteins enabling them to translocate from cytoplasm to nucleus, where they activate a subset of hypertrophic response genes. Transgeni...Calcineurin dephosphorylates multiple serine residues near the N terminus of NFAT proteins enabling them to translocate from cytoplasm to nucleus, where they activate a subset of hypertrophic response genes. Transgenic mice over-expressing a constitu- tively active form of calcineurin or NFAT3, developed obviously hypertrophy and heart failure or sudden death proving its pathogenic role. Here we used literatures on MEDLINE （2000-2011）, systematically reviewed the new development of calcineurin signaling pathway in myocardial hypertrophy展开更多
文摘目的探讨利用能谱CT物质分离技术评价冠状动脉钙化斑块狭窄率的准确性。方法收集行冠状动脉CT能谱成像的86例钙化斑块患者的图像,使用物质分离软件评价钙化斑块的狭窄程度,以冠状动脉造影为金标准进行对比;根据对比结果符合与否分成2组,比较2组之间在图像质量上的差异;根据钙化斑块所在冠状动脉节段管腔直径分为2~mm、3~mm及≥4 mm 3组,比较3组在符合程度上的差异。结果能谱CT扫描共检出256处钙化斑块。利用物质分离技术诊断0、<50%、≥50%和≥70%狭窄的灵敏度分别为88.89%、88.04%、83.08%、75.93%;特异度分别为97.16%、90.24%、92.15%、98.51%。2组在CT值、信躁比(SNR)上的差异有统计学意义,在SD上的差异无统计学意义。钙化斑块所在冠状动脉节段管腔大小影响狭窄率的判断,管腔越大,符合率越高。结论能谱CT物质分离技术评价冠状动脉钙化斑块狭窄率具有较高的准确性,图像质量和钙化斑块所在冠脉节段管腔大小对准确性的影响较大。
文摘Due to the environmental policies and economic reasons,the water used in some flotation operations of complex sulfide ores is recirculated,causing the ion concentration of some species to increase over time,affecting the flotation of the minerals of interest.In this work,an experimental and thermodynamic analysis of the synthetic solutions was presented with a high content of calcium and sulfate ions.The study focused on evaluating the use of two aluminum compounds for the precipitation of Ca^(2+)and SO_(4)^(2−)in the form of ettringite.The amorphous aluminum hydroxide was found to be more efficient than the crystalline one,giving rise to 83%calcium and 91%sulfate removal.The XRD analysis of the solids showed the main reaction product of ettringite,accompanied by small amounts of calcite,due to the absorption of atmospheric carbon dioxide.The final solution after the chemical treatment showed residual calcium and sulfate concentrations below 200 mg/L.Finally,the kinetics of calcium removal appeared to correspond to a second order reaction with respect to calcium concentration,with an apparent activation energy of 53.48 kJ/mol,which may suggest that the ettringite precipitation process is governed by the chemical reaction.
文摘An acid sulfate soil sample was successively extracted with deionized water, 1 mol L-1 KCl and 0.000 5 mol L-l Ca(OH)2 solutions. The results showed that only very small amounts of acidity were extracted by deionized water, possibly through slow jarosite hydrolysis. Acid release through jarosite hydrolysis was greatly enhanced by Ca(OH)2 extraction at the expense of the added OH- being neutralized by the acid released. Successive extraction of the sample with KCl removed the largest amounts of acidity from the sample. However, it is likely that the major form of acidity released by KCl extraction was exchangeable acidity. The results also show the occurrence of low or non charged Al and Fe species in water and Ca(OH)2 extracts after first a few extractions. It appears that such a phenomenon was related to a decreasing EC value with increasing number of extractions.
文摘In the perifused fura-2 loaded exocrine pancreatic acinar cell line AR4-2J pulses of high potassium induced repetitive increases in intracellular calcium. Attached cells when stimulated with high potassium secreted large amount of amylase. High potassium-induced secretion was dependent both on the concentration of potassium and duration of stimulation. High potassium induced increases in intracellular calcium were inhibited by voltage-dependent calcium channel antagonists with an order of potency as follows: nifedipine > ω-agatoxin IVA > ω-conotoxin GVIA. In contrast, the L-type calcium channel antagonist nifedipine almost completely inhibited potassium-induced amylase secretion, whereas the N-type channel antagonist ω-conotoxin GVIA was without effect. The P-type channel antagonist ω-agatoxin IVA had a small inhibitory effect, but this inhibition was not significant at the level of amylase secretion. In conclusion, the AR4-2J cell line possesses different voltage-dependent calcium channels (L, P,N) with the L-type predominantly involved in depolarization induced amylase secretion.
文摘Calcineurin dephosphorylates multiple serine residues near the N terminus of NFAT proteins enabling them to translocate from cytoplasm to nucleus, where they activate a subset of hypertrophic response genes. Transgenic mice over-expressing a constitu- tively active form of calcineurin or NFAT3, developed obviously hypertrophy and heart failure or sudden death proving its pathogenic role. Here we used literatures on MEDLINE （2000-2011）, systematically reviewed the new development of calcineurin signaling pathway in myocardial hypertrophy
