| 1. |
- Zhang, Xiang, et al.
(författare)
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Asymmetric epoxidation of chromenes catalyzed by chiral pyrrolidine SalenMn(III) complexes with an anchored functional group
- 2008
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Ingår i: Applied organometallic chemistry. - : Wiley. - 0268-2605 .- 1099-0739. ; 22:10, s. 592-597
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Tidskriftsartikel (refereegranskat)abstract
- Chiral pyrrolidine SalenMn(III) complexes with an anchored functional group at the N-aza-substituent in the pyrrolidine backbone were synthesized, and used as catalysts for asymmetric epoxidation of substituted chromenes. The complex 1 with an anchored imidazole as acceptor could effectively catalyze epoxidation of substituted chromenes in the absence of expensive additive 4-phenyl pyridine N-oxide (PPNO) by the coordination of the anchored organic base to the central manganese ion. Complexes 2 and 3 with a quaternary ammonium salt unit at the Naza-substituent in the pyrrolidine backbone displayed higher activities than Jacobsen catalyst and the analogous complex 4 without anchored functional group in the aforementioned reaction.
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| 2. |
- Zhang, Zhi-Yong, et al.
(författare)
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Nup88 expression in normal mucosa, adenoma, primary adenocarcinoma and lymph node metastasis in the colorectum
- 2007
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Ingår i: Tumor Biology. - : Springer Science and Business Media LLC. - 1010-4283 .- 1423-0380. ; 28:2, s. 93-99
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: It was the aim of this study to investigate Nup88 expression in normal colorectal mucosa, adenoma, adenocarcinoma and lymph node metastasis, as well as the relationship between Nup88 expression and clinicopathological features. Methods: Nup88 expression was examined by immunohistochemistry in 84 normal mucosa samples, 32 adenomas, 181 primary adenocarcinomas, and 18 lymph node metastases from colorectal tumour patients. Results: Nup88 expression was observed in normal epithelial and tumour cells. The frequency of strong Nup88 expression was increased from normal mucosa or adenoma to primary tumour and lymph node metastasis (p < 0.0001). There was no significant difference in the expression between normal mucosa and adenoma (p = 0.41). The frequency of strong Nup88 expression was higher in ulcerated tumours (40%) than in polypoid/large fungating tumours (23%, p = 0.048). The frequency of strong Nup88 expression was significantly different among tumours with good (21%), moderate (42%) and poor differentiation (48%, p = 0.01). Nup88 expression was not related to the patients' gender, age, tumour location, size, histological type, invasive depth, lymph node status and Dukes stage (p > 0.05). Conclusion: Our results suggest that Nup88 may play a role during the development, aggressiveness and differentiation of colorectal tumours. Copyright © 2007 S. Karger AG.
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| 3. |
- Gao, Jingfang, 1966-, et al.
(författare)
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Association of NFKBIA polymorphism with colorectal cancer risk and prognosis in Swedish and Chinese populations
- 2007
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Ingår i: Scandinavian Journal of Gastroenterology. - : Informa UK Limited. - 0036-5521 .- 1502-7708. ; 42:3, s. 345-350
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Tidskriftsartikel (refereegranskat)abstract
- Objective. The inhibitory proteins, IκBs, regulate the activity of nuclear factor kappa-beta (NF-κB), which is implicated in tumorigenesis by regulating expression of a variety of genes involved in cellular transformation, proliferation, invasion, angiogenesis and metastasis. Variants in the genes encoding IκBs may be involved in cancer development through the activation of NF-κB. The objective of this study was to investigate the susceptibility of an A to G variation (rs696) in the 3′ UTR of NFKBIA (encoding IκBα) to colorectal cancer (CRC) and the association of this polymorphism with clinicopathologic variables in CRC patients. Material and methods. A case-control study was carried out on a Swedish (155 CRCs, 438 controls) and a Chinese population (199 CRCs, 577 controls). The genotype of NFKBIA was determined by PCR-restriction fragment length polymorphism. Results. The frequency of the AG genotype was increased in the Chinese patients ≥50 years of age compared with the Chinese controls (odds ratio (OR) = 3.06, 95% confidence interval (CI) = 1.55-6.02, p=0.001), even when adjusted for age (OR = 3.20, 95% CI = 1.61-6.38, p=0.001). The GG genotype of NFKBIA was related to a poorer survival rate in the Swedish patients, independent of gender, age, tumour location, Dukes' stage and differentiation (hazard ratio = 3.10, 95% Cl = 1.28-7.60, p=0.01). Conclusions. Chinese individuals ≥50 years of age carrying the AG genotype of NFKBIA may be at an increased risk of developing CRC, and the GG genotype of NFKBIA may be considered as a prognostic factor for Swedish CRC patients. © 2007 Taylor & Francis.
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| 4. |
- Zhang, Xiang, et al.
(författare)
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Intramolecularly two-centered cooperation catalysis for the synthesis of cyclic carbonates from CO2 and epoxides
- 2008
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Ingår i: Tetrahedron Letters. - : Elsevier BV. - 0040-4039 .- 1359-8562. ; 49:46, s. 6589-6592
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Tidskriftsartikel (refereegranskat)abstract
- A catalyst systern containing an electrophilic center and a sterically hindered nUcleophilic center in one molecule was applied to the cycloaddition reaction of CO2 and epoxides. This intramolecularly two-centered cooperation catalyst showed activity even at a high [epoxide]/[catalyst] ratio up to 50000 under mild conditions such as solvent-free, ambient temperature, and low CO2 pressure. The reaction of CO2 with (S)-propylene oxide at 80 degrees C in the presence of the bifunctional catalyst gives (S)-propylene carbonate in 96% ee with retention of stereochemistry.
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