cDNA microarray data are subject to many sources of variation that have to be removed before statistical tests can be applied for identifying genes that are expressed differentially.Background correction,log-ratio tra...cDNA microarray data are subject to many sources of variation that have to be removed before statistical tests can be applied for identifying genes that are expressed differentially.Background correction,log-ratio transformation,and normalization,referred as the log-ratio approach,have been widely used for this purpose.However,there are some problems associated with this procedure.In this study,we proposed an altemative approach that obviates the log-ratio transformation step and goes directly to normalization after background correction.The method can estimate the"noise"effect by utilizing the information more effectively Simulation studies were carried out to compare the feasibility and efficiency of this approach for detecting the specifically and differentially expressed genes under various conditions with the log-ratio approach.The results showed that our approach worked well and was more robust and powerful than the log-ratio approach.展开更多
The Y 2O 3-CeO 2-ZrO 2 powders were prepared using a co-precipitation process and the corresponding coatings were prepared by plasma spraying. The results show that an optimal composition exists in Y 2O 3-doped ...The Y 2O 3-CeO 2-ZrO 2 powders were prepared using a co-precipitation process and the corresponding coatings were prepared by plasma spraying. The results show that an optimal composition exists in Y 2O 3-doped CeO 2-ZrO 2, but not in CeO 2-doped Y 2O 3-ZrO 2. The powders mainly contain tetragonal phase and a trace amount of monoclinic phase. The homogeneity in composition, large agglomerate size, ideal particle size distribution and high flowability were obtained. The as-sprayed coatings are composed of non-transformable tetragonal phase, tz′structure, and resistant to transformation under thermal or mechanical stresses.展开更多
基金Supported by the National Key Basic Research Program of China(No.G2000016103).
文摘cDNA microarray data are subject to many sources of variation that have to be removed before statistical tests can be applied for identifying genes that are expressed differentially.Background correction,log-ratio transformation,and normalization,referred as the log-ratio approach,have been widely used for this purpose.However,there are some problems associated with this procedure.In this study,we proposed an altemative approach that obviates the log-ratio transformation step and goes directly to normalization after background correction.The method can estimate the"noise"effect by utilizing the information more effectively Simulation studies were carried out to compare the feasibility and efficiency of this approach for detecting the specifically and differentially expressed genes under various conditions with the log-ratio approach.The results showed that our approach worked well and was more robust and powerful than the log-ratio approach.
文摘The Y 2O 3-CeO 2-ZrO 2 powders were prepared using a co-precipitation process and the corresponding coatings were prepared by plasma spraying. The results show that an optimal composition exists in Y 2O 3-doped CeO 2-ZrO 2, but not in CeO 2-doped Y 2O 3-ZrO 2. The powders mainly contain tetragonal phase and a trace amount of monoclinic phase. The homogeneity in composition, large agglomerate size, ideal particle size distribution and high flowability were obtained. The as-sprayed coatings are composed of non-transformable tetragonal phase, tz′structure, and resistant to transformation under thermal or mechanical stresses.
