The modification by MnOx significantly enhanced the activity and stability of Co3O4 for the preferential oxidation of CO in H2-rich stream. The MnOx-promoted Co3O4 catalyst with a Mn/Co molar ratio of 1/8 exhibited the best performance; CO conversion was 56% at 40°C and increased to >90% as the temperature was raised to >75°C. This catalyst could provide 100% CO conversion at 125–175°C. CO conversions of 97% and 100% remained unchanged for 100h at 100 and 125°C, respectively, whereas the deactivation was observed over Co3O4 alone. Our characterizations using XRD, XPS and TEM indicated that the modification of Co3O4 with MnOx caused the formation of smaller MnxCo3−xO4 solid-solution particles. The O2-TPD, CO-TPD, and pulse reaction studies suggest that the incorporation of MnOx into Co3O4 increased the amounts of reactive oxygen species and adsorbed CO species over catalyst surfaces and enhanced the regeneration ability of the reduced catalyst by O2. All these enhancements are proposed to be responsible for the improved catalytic performance of the MnOx-promoted Co3O4.

A series of Co–Cu composite oxides with different Co/Cu atomic ratios were prepared by a co-precipitation method. XRD, N2 sorption, TEM, XPS, H2-TPR, CO-TPR, CO-TPD and O2-TPD were used to characterize the structure and redox properties of the composite oxides. Only spinel structure of Co3O4 phase was confirmed for the Co–Cu composite oxides with Co/Cu ratios of 4/1 and 2/1, but the particle sizes of these composite oxides decreased evidently compared with Co3O4. These composite oxides could be reduced at lower temperatures than Co3O4 by either H2 or CO. CO and O2 adsorption amounts over the composite oxides were significantly higher than those over Co3O4. These results indicated a strong interaction between cobalt and copper species in the composite samples, possibly suggesting the formation of Cu x Co3−x O4 solid solution. For the preferential oxidation of CO in a H2-rich stream, the Co–Cu composite oxides (Co/Cu = 4/1–1/1) showed distinctly higher catalytic activities than both Co3O4 and CuO, and the formation of Cu x Co3−x O4 solid solution was proposed to contribute to the high catalytic activity of the composite catalysts. The Co–Cu composite oxide was found to exhibit higher catalytic activity than several other Co3O4-based binary oxides including Co–Ce, Co–Ni, Co–Fe and Co–Zn oxides.

The unsupported Co3O4 catalyst showed excellent low temperature CO oxidation activity.Its application for carbon monoxide preferential oxidation has attracted a great attention since it exhibited a potential prospect for industrial application.In this report,Co3O4 nanoparticles with two different kinds of morphologies were prepared by liquid-precipitation air-oxidation pyrolysis method.In order to investigate the impact of preparation conditions(such as precipitating agents,aging time and calcination temperature) on the morphology and crystal size of Co3O4 nanoparticles,we used XRD,SEM to characterize the prepared Co3O4.Morphologies of Co3O4 are consistent with the morphology of their precipitation precursors.The higher the calcination temperature was,the larger the crystal size became.Catalytic preferential oxidation of carbon monoxide over Co3O4 nanoparticles in H2-rich gas was performed.We compared the catalytic performance of Co3O4 synthesized by above methods,found that size and surface area of the catalyst had correlation with its catalytic activity.The Co3O4 obtained by urea-precipitation air-oxidation method calcination at 250～300℃ exhibits the best activity.

Proc Amer Assoc Cancer Res, Volume 47, 2006 5002 PTX1 is a gene identified by subtractive hybridization on the basis that it is expressed in normal prostate and not in prostatic carcinoma. It is unrelated to the pituitary homeobox protein (Ptx1 or Pitx1) that regulates pituitary hormone gene expression, and its function is currently unknown. Recently, it was found to be identical to Erv41, an endoplasmic reticulum (ER) resident protein involved in protein trafficking between ER and Golgi. Our earlier study showed that ectopic expression of PTX1 in prostate cancer cell line, PC-3, induced cellular senescence. To study its mechanism of action, we transfected PC-3 cells with PTX1 expression construct and determined the genes that were up-regulated by PTX1 using gene expression profiling, reverse transcriptase-PCR, and promoter-luciferase reporter assay. Gene expression microarray analyses showed that interferon-β (IFN-β) and a number of IFN-inducible proteins, among other proteins, were up-regulated by PTX1 expression. Up-regulation of IFN-β by PTX1 was confirmed by RT-PCR and a PTX1 responsive element upstream from the IFN-β gene was identified by promoter-luciferase reporter assay. These results suggest that PTX1 may induce cellular senescence in PC-3 cells via the IFN-β pathway. However, ectopic expression of IFN-β in PC-3 cells did not induce senescence. Since PTX1-induced senescence in PC-3 cells cannot be explained by up-regulation of IFN-β alone, other PTX1-induced protein(s) may also be involved in this process.

PTX1 is a gene identified by subtractive hybridization on the basis that it is expressed in normal prostate and not in prostate carcinoma. It is unrelated to the pituitary homeobox protein (Ptx1 or Pitx1), which regulates pituitary hormone gene expression, and its function is currently unknown. Recently, it was found to be a homolog of the yeast Erv41p, an endoplasmic reticulum (ER) resident protein involved in protein trafficking between ER and Golgi, and was renamed as ERGIC2. Ectopic expression of a partial sequence of PTX1 (Met84 - Leu225) as a VP22-fusion protein in prostate cancer cell line, PC-3, induced cellular senescence. Gene expression microarray analyses showed that interferon-beta (IFN-beta) and a number of IFN-inducible genes, among other genes, were upregulated by the PTX1-VP22 fusion protein. Upregulation of IFN-beta was confirmed by RTPCR and promoter-reporter assay. However, the upregulation of IFN-beta by the PTX1-VP22 fusion protein was not due to nuclear translocation of the PTX1 luminal domain.

PTX1 is a gene identified by subtractive hybridization on the basis that it is expressed in normal prostate and not in prostate carcinoma. It encodes a nuclear protein that is downregulated in prostate carcinoma. Expression constructs containing PTX1 cDNA in both sense and antisense orientations were transfected into prostate tumor cell line, PC-3 cells. The effects of the expression of PTX1 and antisense PTX1 on PC-3 cells were examined using cell growth, proliferation, soft agar, invasion chamber, senescence-associated beta-galactosidase, and nude mice assays. Cells transfected with PTX1 construct in the sense orientation were growth-arrested. These cells displayed multiple morphological changes consistent with cellular senescence, including the expression of a senescence-associated beta-galactosidase. On the other hand, expression of antisense PTX1 RNA in PC-3 cells resulted in uncontrolled cell growth and increase of invasive potential. In nude mice, cells expressing antisense PTX1 grew sixfold faster than the control. These results suggest that PTX1 may play an important role in the growth and tumorigenicity of PC-3 cells.

A cDNA, designated PTX1, has been isolated by subtractive hybridization on the basis that it is expressed in normal prostate but not in prostate carcinoma. The full-length cDNA was subsequently established by 5' and 3' RACE. Nucleotide sequence analysis of the 5'- and 3'-RACE clones yielded a composite cDNA of 1327 bp, which predicted a protein of 377 amino acid residues with a putative nuclear import signal (RRLNRKK) at its N terminus. The PTX1 gene was localized to human chromosome 12 and was found to be ubiquitously expressed. A segment of the cDNA was expressed in E. coli to produce a fragment of the PTX1 protein for the generation of specific antibodies. The resulting antibodies detected a 73-kDa protein in both nuclear and cytoplasmic extracts of prostate, although the level in the cytoplasmic extract was much lower. Using immunohistochemical analysis, the PTX1 protein was localized mainly in the nuclei of glandular epithelia of normal prostate. The nuclear staining was greatly reduced in prostate carcinoma. The gene organization of PTX1 was established by comparing the cDNA sequence with the published human genomic sequence.