| 1. |
- Li, Yan-Ling, et al.
(författare)
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Formation of Nanofoam carbon and re-emergence of Superconductivity in compressed CaC6
- 2013
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 3, s. 3331-
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Tidskriftsartikel (refereegranskat)abstract
- Pressure can tune material's electronic properties and control its quantum state, making some systems present disconnected superconducting region as observed in iron chalcogenides and heavy fermion CeCu2Si2. For CaC6 superconductor (T-c of 11.5 K), applying pressure firstTc increases and then suppresses and the superconductivity of this compound is eventually disappeared at about 18 GPa. Here, we report a theoretical finding of the re-emergence of superconductivity in heavily compressed CaC6. The predicted phase III (space group Pmmn) with formation of carbon nanofoam is found to be stable at wide pressure range with a Tc up to 14.7 K at 78 GPa. Diamond-like carbon structure is adhered to the phase IV (Cmcm) for compressed CaC6 after 126 GPa, which has bad metallic behavior, indicating again departure from superconductivity. Re-emerged superconductivity in compressed CaC6 paves a new way to design new-type superconductor by inserting metal into nanoporous host lattice.
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| 2. |
- Li, Yan-Ling, et al.
(författare)
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Pressure-induced superconductivity in CaC2
- 2013
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 110:23, s. 9289-9294
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Tidskriftsartikel (refereegranskat)abstract
- Carbon can exist as isolated dumbbell, 1D chain, 2D plane, and 3D network in carbon solids or carbon-based compounds, which attributes to its rich chemical binding way, including sp-, sp(2)-, and sp(3)-hybridized bonds. sp(2)-hybridizing carbon always captures special attention due to its unique physical and chemical property. Here, using an evolutionary algorithm in conjunction with ab initio method, we found that, under compression, dumbbell carbon in CaC2 can be polymerized first into 1D chain and then into ribbon and further into 2D graphite sheet at higher pressure. The C2/m structure transforms into an orthorhombic Cmcm phase at 0.5 GPa, followed by another orthorhombic Immm phase, which is stabilized in a wide pressure range of 15.2-105.8 GPa and then forced into MgB2-type phase with wide range stability up to at least 1 TPa. Strong electron-phonon coupling. in compressed CaC2 is found, in particular for Immm phase, which has the highest lambda value (0.562-0.564) among them, leading to its high superconducting critical temperature T-c (7.9 similar to 9.8 K), which is comparable with the 11.5 K value of CaC6. Our results show that calcium not only can stabilize carbon sp(2) hybridization at a larger range of pressure but also can contribute in superconducting behavior, which would further ignite experimental and theoretical interest in alkaline-earth metal carbides to uncover their peculiar physical properties under extreme conditions.
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| 3. |
- Yang, Zhi-Ling, et al.
(författare)
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Molecular evolution and expression divergence of the Populus polygalacturonase supergene family shed light on the evolution of increasingly complex organs in plants
- 2013
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Ingår i: New Phytologist. - : Wiley. - 0028-646X .- 1469-8137. ; 197:4, s. 1353-1365
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Tidskriftsartikel (refereegranskat)abstract
- Plant polygalacturonases (PGs) are involved in cell separation processes during many stages of plant development. Investigation into the diversification of this large gene family in land plants could shed light on the evolution of structural development. We conducted whole-genome annotation, molecular evolution and gene expression analyses of PG genes in five species of land plant: Populus, Arabidopsis, rice, Selaginella and Physcomitrella. We identified 75, 44, 16 and 11 PG genes from Populus, rice, Selaginella and Physcomitrella genomes, respectively, which were divided into three classes. We inferred rapid expansion of class I PG genes in Populus, Arabidopsis and rice, while copy numbers of classes II and III PG genes were relatively conserved in all five species. Populus, Arabidopsis and rice class I PG genes were under more relaxed selection constraints than class II PG genes, while this selective pressure divergence was not observed in Selaginella and Physcomitrella PG families. In addition, class I PG genes underwent marked expression divergence in Populus, rice and Selaginella. Our results suggest that PG gene expansion occurred after the divergence of the lycophytes and euphyllophytes, and this expansion was likely paralleled by the evolution of increasingly complex organs in land plants.
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| 4. |
- Zhang, Zhi Y, et al.
(författare)
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PINCH mRNA Overexpression in Colorectal Carcinomas Correlated with VEGF and FAS mRNA Expression
- 2011
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Ingår i: Anticancer Research. - : International Institute of Anticancer Research (IIAR). - 0250-7005 .- 1791-7530. ; 31:12, s. 4127-4133
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND:Particularly interesting new cysteine-histidine-rich protein (PINCH) was found to be up-regulated in the stroma of colorectal carcinomas (CRCs) in our previous studies and was involved in angiogenesis through activation of fibroblasts in extracellular matrix (ECM) in response to tumors. Here, we examined PINCH mRNA expression in colorectal cancer and investigated its relationship with the clinicopathological features and proliferation cell nuclear antigen (PCNA), vascular endothelial growth factor (VEGF) and FAS.MATERIALS AND METHODS:The primary cancer tissues, adjacent noncancerous tissues and the proximal and distant margins of normal mucosa were collected from 81 colorectal cancer patients during surgery. PINCH, PCNA, VEGF and FAS mRNA expression was examined by reverse transcriptional PCR (RT-PCR).RESULTS:PINCH mRNA expression was significantly increased in primary tumors compared with that in adjacent noncancerous tissues, and the proximal and distant margins of normal mucosa (p<0.0001). Expression of PINCH mRNA in colon cancer tended to be higher than expression in rectal cancer (p=0.051). Tumors which had infiltrated through the wall of the colorectum trended to have higher PINCH mRNA expression (p=0.073). PINCH mRNA expression in primary tumors was positively related to the expression of PCNA mRNA (r=0.534, p=0.010), VEGF mRNA (r=0.431, p=0.022) and FAS mRNA (r=0.542, p=0.012).CONCLUSION:PINCH mRNA was overexpressed in colorectal cancer and associated with PCNA mRNA, VEGF mRNA and FAS mRNA expression. PINCH mRNA was involved in the development of colorectal cancer and might play a role in the epithelial mesenchymal transition in the rectum differently than in the colon, through the adenomatous polyposis coli (APC)/catenin pathway.
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| 5. |
- Zhao, Zeng-Ren, et al.
(författare)
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Nup88 mRNA overexpression in colorectal cancers and relationship with p53
- 2010
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Ingår i: CANCER BIOMARKERS. - : IOS Press. - 1574-0153. ; 8:2, s. 73-80
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: We measured nucleoporin 88 (Nup88) mRNA expression in primary colorectal cancers to investigate its relationship with clinicopathological features and p53. Methods: The primary cancer tissues, adjacent noncancerous tissues and the proximal and distant margins of normal mucosa were collected from 73 colorectal cancer patients during surgery. Nup88 mRNA expression was measured on these fresh specimens and on colon cell lines HCT-116 (P53+/+) and HCT-116 (P53-/-) by RT-PCR while p53 mRNA and beta-actin as controls. Nup88 and p53 protein expression were then immunohistochemistrically examined in other 25 colorectal cancers specimens paraffin embedded and formalin fixed. Results: Nup88 expression was higher in primary cancer tissues than in adjacent noncancerous tissues, and in the proximal and distant margins of normal mucosa. Overexpression of Nup88 mRNA was statistically associated with TNM stage (P = 0.044), lymphatic metastasis (P = 0.022), and cancer location (P = 0.036), while not related to gender, age of patients and histological type, infiltration depth, and differentiation of cancers. The expression of Nup88 mRNA in the HCT-116 (P53-/-) cell line was not significantly different from expression in the HCT-116 (P53+/+) cell line. And there was no correlation between Nup88 and p53 protein expression (r = 0.632, P = 0.368). Conclusions: Nup88 mRNA was overexpressed in colorectal cancers and the overexpression was associated with cancer development and aggressiveness. Nup88 might be regard as essential contributor to nodal metastagenicity of colorectal cancer.
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| 6. |
- Zhao, Zeng-Ren, et al.
(författare)
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Significance of mRNA and Protein Expression of MAC30 in Progression of Colorectal Cancer
- 2011
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Ingår i: Chemotherapy. - Basel : Karger AG. - 0009-3157 .- 1421-9794. ; 57:5, s. 394-401
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Tidskriftsartikel (refereegranskat)abstract
- Background: Meningioma-associated protein (MAC30), first described to be overexpressed in meningiomas, exhibits altered expression in certain human tumors. The aim of our study was to investigate the expression of MAC30 mRNA and its correlation with clinicopathological variables in human colorectal cancer (CRC). Methods: MAC30 mRNA expression was first examined in 55 CRCs, along with the samples from the matched distant normal and adjacent noncancerous tissue by RT-PCR, further verified in 18 CRCs by quantitative RT-PCR. MAC30 protein expression was detected by Western blot in 10 CRCs, and DNA sequencing was performed in 1 case of the paired CRC and the matched noncancerous specimen. MAC30 mRNA expression in two colon cancer cell lines, HCT-116(p53-/-) and HCT-116(p53+/+), was detected by quantitative RT-PCR. Results: The mRNA expression of MAC30 was increased in CRC when compared with distant normal (p < 0.01) and adjacent noncancerous mucosa (p < 0.01). The mean value of MAC30 mRNA expression in the tumor located in the colon was higher than in the rectum (0.677 +/- 0.419 vs. 0.412 +/- 0.162, p = 0.005). As the tumor penetrated the wall of the colon/rectum, MAC30 mRNA expression notably increased in tumors with T3+T4 stage compared to tumors with T1+T2 stage (0.571 +/- 0.364 vs. 0.404 +/- 0.115, p = 0.014). MAC30 protein expression in CRCs was also remarkably elevated compared to the adjacent noncancerous mucosa. There was no mutation in the coding region of the MAC30 gene either in CRC or in the noncancerous mucosa. mRNA expression of p53 was notably decreased in HCT-116(p53-/-) compared to HCT-116(p53+/+), while MAC30 did not vary greatly. Conclusion: The overexpression of MAC30 might be involved in the development and aggressiveness of CRCs, especially in the colon.
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