Effects of Fe2O3 addition on the nitridation of silicon powder

The reaction of silicon powder and nitrogen was studied in the range of 1300-1400 C. When an addition of Fe2O3 was more than 0.8wt%, the reaction was linear and compared to samples with no Fe2O3, the reaction velocity increased 5 to 10 times. The reactions were mediated by the process of peeling and cracking in a thin layer of Si2N4 formed on the silicon particles or on the surface of the Fe-Si melts. As the addition of Fe2O3 increased, the reaction activation energy for highly pure samples decreased. Fe2O3 which exceeded the Si3N4 solubility limits was finally converted to d-Fe

Influence of fibers on the dust dislodgement efficiency of bag filters

In recent years non-woven bag filters have been used in waste incinerators for the efficient collection of dust and removal of detrimental gas. However, dust collection efficiency decreases with time until the bag filters are no longer effective. Dust adhering to the fabric is a major determinant of bag filter life. In the present study a flat filter was used to study the relationship between various parameters of a bag filter structure and its dust dislodgement efficiency. The results confirm that fiber linear density, modulus of elasticity, and the form of the fiber cross-section of the felt can each affect the dust collection efficiency of a bag filter. Higher fiber linear density in a bag filter prevents dust from penetrating the filter, and this allows the dust to be more easily dislodged from the filter. Examination of various forms of fiber cross-section indicates that for the same fiber linear density the triangular form is better than the circular form. A lower Young's modulus allows the fiber to bend more easily and prevents the dust from penetrating the filter. Fiber linear density, fiber modulus of elasticity and form of the fiber cross-section are the variables affecting bag filter efficiency.ArticleTEXTILE RESEARCH JOURNAL. 84(7):764-771 (2014)journal articl

Advanced simulation code for alpha spectrometry

A Monte Carlo code, known as AASI, is developed for simulating energy spectra in alpha spectrometry. The code documented here is a comprehensive package where all the major processes affecting the spectrum are included. A unique feature of the code is its ability to take into account coincidences between the particles emitted from the source. Simulations and measurements highlight the importance of coincidences in high-resolution alpha spectrometry. To show the validity of the simulated results, comparisons with measurements and other simulation codes are presented.Comment: 21 pages, 4 figures, to be published in Nucl. Instr. and Meth.

Tumor Uptake Study of 18F-labeled N-Acetylneuraminic Acids

開始ページ、終了ページ: 冊子体のページ付

Ribozyme-mediated inactivation of mutant K-ras oncogene in a colon cancer cell line

Mutation of c-K-ras oncogene is an important step in progression of colon cancer. We used a hammerhead ribozyme (KrasRz) against mutated K-ras gene transcripts (codon 12, GTT) to inactivate mutant K-ras function in the colon cancer cell line SW480, harbouring a mutant K-ras gene. The β-actin promoter-driven KrasRz sequence (pHβ/KrasRz) was introduced into these cells (SW480/KrasRz), and we evaluated its effects on growth of the colon cancer. The gene expression of angiogenesis-related molecules (vascular endothelial growth factor and thrombospondin) was also estimated in SW480/KrasRz. KrasRz specifically and efficiently cleaved the mutant K-ras mRNA but not wild-type mRNA in vitro. SW480/KrasRz showed decreased growth rate under tissue culture conditions (P< 0.01, Dunnett’s test). The xenotransplantability of SW480/KrasRz (XeSW480/KrasRz) was significantly decreased in nude mice (P< 0.05, Fisher’s exact test). Tumour volume of the xenografts XeSW480/KrasRz was significantly smaller than that of XeSW480/DisKrasRz (P< 0.01, Dunnett’s test). Gene expression of VEGF was suppressed in SW480/KrasRz, while TSP1 gene expression was enhanced. The SW480/KrasRz cells showed apoptosis-related features including nuclear condensation and DNA fragmentation. These results suggested that the hammerhead ribozyme-mediated inactivation of the mutated K-ras mRNA induced growth suppression, apoptosis and alteration of angiogenic factor expression. © 2000 Cancer Research Campaig