| 1. |
- Ablikim, M., et al.
(författare)
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Measurements of (XcJ)-> K+K-K+K- decays
- 2006
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Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 642:3, s. 197-202
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Tidskriftsartikel (refereegranskat)abstract
- Using 14M psi(2S) events taken with the BESII detector, chi(cJ) -> 2(K+K-) decays are studied. For the four-kaon final state, the branching fractions are B(chi(c0,1,2) ->.2(K+K-)) = (3.48 +/- 0.23 +/- 0.47) x 10(-3), (0.70 +/- 0.13 +/- 0.10) x 10(-3), and (2.17 +/- 0.20 +/- 0.31) x 10(-3). For the phi K+K- final state, the branching fractions, which are measured for the first time, are B(chi(c0,1,2) -> phi K+K-) = (1.03 +/- 0.22 +/- 0.15) x 10(-3), (0.46 +/- 0.16 +/- 0.06) x 10(-3), and (1.67 +/- 0.26 +/- 0.24) x 10(-4). For the phi phi final state, B(chi(c0,2) -> phi phi) = (0.94 +/- 0.21 +/- 0.13) x 10(-3) and (1.70 +/- 0.30 +/- 0.25) x 10(-3).
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| 2. |
- Tian, Yu-Peng, et al.
(författare)
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Investigations and facile synthesis of a series of novel multi-functional two-photon absorption materials
- 2007
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Ingår i: Journal of Materials Chemistry. - : Royal Society of Chemistry (RSC). - 0959-9428 .- 1364-5501. ; 17:34, s. 3646-3654
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Tidskriftsartikel (refereegranskat)abstract
- Six centrosymmetric D-(pi-A)(3) structural triphenylamine derivatives that can be used as two- photon photopolymerization and optical data storage chromophores, tris[ 4-( 4- pyridylethenyl) phenyl] amine ( 1), tris[ 4-( 2- pyridylethenyl) phenyl] amine ( 2), tris( 4- cyanoethenylphenyl) amine ( 3), tris[ 4- butylacrylatephenyl] amine ( 4), tris[ 4- methylacrylatephenyl] amine ( 5) and tris[ 4- acrylicethenylphenyl] amine ( 6), have been successfully synthesized via a triple palladium-catalyzed Heck coupling reaction, and the novel chromophores were fully characterized by elemental analysis, IR, (1)H-NMR and ESIMS. The structure for 3 was determined by single crystal X-ray diffraction study. One- and two-photon absorption and fluorescence in various solvents were experimentally investigated. Two-photon initiated polymerization microfabrication and optical data recording experiments were carried out under 780 nm laser radiation, and the possible polymerization mechanism is discussed based on theoretical calculations. All the six chromophores have relatively large two-photon absorption crosssections, and exhibit optical memory and highly efficient two-photon initiated polymerization abilities.
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| 3. |
- Sun, Hongfei, et al.
(författare)
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Synthesis and structure of a mu-oxo diiron(III) complex with an N-pyridylmethyl-N,N-bis(4-methylbenzimidazol-2-yl)amine ligand and its catalytic property for hydrocarbon oxidation
- 2008
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Ingår i: Applied organometallic chemistry. - : Wiley. - 0268-2605 .- 1099-0739. ; 22:10, s. 573-576
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Tidskriftsartikel (refereegranskat)abstract
- A mu-oxo diiron(III) complex [{Fe(pbba)Cl}(2)(mu-O)]Cl-2 (1, pbba = N-pyridylmethyl-N,N-bis(4-methylbenzimidazol-2-yl)amine) bearing multi-imidazolyl motifs was synthesized and characterized by X-ray crystallography to closely mimic the structural features of methane monooxygenase. As shown by its X-ray crystal structure, complex 1 is a centrosymmetric dimer with an Fe-O-Fe angle of 180 degrees, and pseudo-octahedral around each iron(III) center. The catalytic ability of title compound in the oxidation of alkane and alkene is investigated by employing tert-butylhydroperoxide and m-chloroperbenzoic acid as oxidants under mild conditions. The catalytic oxidation results showed that radical intermediate dominates the oxidation process.
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| 4. |
- Cui, Hong-Guang, et al.
(författare)
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Synthesis, structures and electrochemical properties of hydroxyl- and pyridyl-functionalized diiron azadithiolate complexes
- 2007
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Ingår i: Polyhedron. - : Elsevier BV. - 0277-5387 .- 1873-3719. ; 26:4, s. 904-910
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Tidskriftsartikel (refereegranskat)abstract
- The hydroxyl- and pyridyl-functionalized diiron azadithiolate complexes [[(mu-SCH2)(2)N(CH2CH2OH)}Fe-2(CO)(6)] (1) and [{(mu-SCH2)(2)N(CH2CH2OOCPy)} Fe-2(CO)(6)] (Py = pyridyl) (2) were prepared as biomimetic models of the active site of Fe-only hydrogenases. Both complexes were characterized by MS, IR, H-1 NMR spectra and elemental analysis. The molecular structures of 1 and 2 were determined by single crystal X-ray analysis. A network is constructed by intermolecular H-bonds in the crystals of 1. An S center dot center dot center dot O intermolecular contact was found in the crystals of 2, which is scarcely found for organometallic complexes. Cyclic voltammograms of 1 and 2 were studied to evaluate their redox properties.
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| 5. |
- Dong, Jin Song, et al.
(författare)
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Timed Automata Patterns
- 2008
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Ingår i: IEEE Transactions on Software Engineering. - 0098-5589 .- 1939-3520. ; 34:6, s. 844-859
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Tidskriftsartikel (refereegranskat)
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| 6. |
- Duan, Lele, et al.
(författare)
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Synthesis, protonation and electrochemical properties of trinuclear NiFe2 complexes Fe-2(CO)(6)(mu(3)-S)(2) Ni(Ph2PCH2)(2)NR (R = n-Bu, Ph) with an internal pendant nitrogen base as a proton relay
- 2009
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Ingår i: Inorganica Chimica Acta. - : Elsevier BV. - 0020-1693 .- 1873-3255. ; 362:2, s. 372-376
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Tidskriftsartikel (refereegranskat)abstract
- Two trinuclear NiFe2 complexes Fe-2(CO)(6)(mu(3)-S)(2)[Ni(Ph2PCH2)(2)NR] (R = n-Bu, 1; Ph, 2) containing an internal base were prepared as biomimetic models for the active sites of FeFe and NiFe hydrogenases. Treatment of complex Fe-2(CO)(6)(mu(3)-S)(2)[Ni(Ph2PCH2)(2)N(n-Bu)] (1) with HOTf gave an N-protonated complex [Fe-2(CO)(6)(mu(3)-S)(2){Ni(Ph2PCH2)(2)NH(n-Bu)}][OTf] ([1H][OTf]). The structures of complexes 1, 2 and [1H][OTf] were determined by X-ray crystallography, which shows that the proton held by the N atom of [1H][OTf] lies in an equatorial position. Cyclic voltammograms of complexes 1 and [1H][OTf] were studied and compared with that of Fe-2(CO)(6)(mu(3)-S)(2)[Ni(dppe)].
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| 7. |
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| 8. |
- Kotsopoulos, Joanne, et al.
(författare)
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Infertility, treatment of infertility, and the risk of breast cancer among women with BRCA1 and BRCA2 mutations : a case-control study
- 2008
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Ingår i: Cancer Causes and Control. - : Springer Science and Business Media LLC. - 1573-7225 .- 0957-5243. ; 19:10, s. 9-1111
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Women with a breast cancer susceptibility gene 1 (BRCA1) or breast cancer susceptibility gene 2 (BRCA2) mutation are at increased risk for developing breast and ovarian cancer. Various reproductive and hormonal factors have been shown to modify the risk of breast cancer. These studies suggest that estrogen exposure and deprivation are important in the etiology of hereditary cancer. Many patients are interested in the possibility of an adverse effect of fertility treatment on breast cancer risk. It is important to evaluate whether or not infertility per se or exposure to fertility medications increase the risk of breast cancer in genetically predisposed women.METHODS: We conducted a matched case-control study of 1,380 pairs of women with a BRCA1 or BRCA2 mutation to determine if a history of infertility, the use of fertility medications, or undergoing in vitro fertilization (IVF) were associated with and increased the risk of breast cancer.RESULTS: Sixteen percent of the study subjects reported having experienced a fertility problem and 4% had used a fertility medication. Women who had used a fertility medication were not at significantly increased risk of breast cancer (odds ratio [OR] = 1.21; 95% confidence interval [CI] = 0.81-1.82) compared to non-users. Furthermore, there was no risk associated with a history of use of a fertility medication when the subjects were stratified by parity: (OR = 1.29; 95% CI = 0.83-2.01 for nulliparous women and OR = 0.81; 95% CI = 0.30-2.22 for parous women).CONCLUSIONS: The results of this study suggest that the use of fertility medications does not adversely affect the risk of breast cancer among BRCA mutation carriers. Given the small sizes of the exposed subgroups, these findings should be interpreted with caution and confirmatory studies are required.
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| 9. |
- Lele, Duan, et al.
(författare)
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Carbene-pyridine chelating 2Fe2S hydrogenase model complexes as highly active catalysts for the electrochemical reduction of protons from weak acid (HOAc)
- 2007
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Ingår i: Dalton Transactions. - : Royal Society of Chemistry (RSC). - 1477-9226 .- 1477-9234. ; :13, s. 1277-1283
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Tidskriftsartikel (refereegranskat)abstract
- Two asymmetrically disubstituted diiron complexes (mu-pdt)[Fe(CO)(3)][Fe(CO)(eta(2)-L)] (L = 1-methyl-3-(2-pyridyl)imidazol-2-ylidene (NHCMePy), 2; 1,3-bis(2-picolyl) imidazol-2-ylidene (NHCdiPic), 4) and a mono-substituted diiron complex (mu-pdt)[Fe(CO)(3)][Fe(CO)(2)(NHCdiPic)] (3) were prepared as biomimetic models of the Fe-only hydrogenase active site. X-Ray studies show that the NHCMePy and NHCdiPic ligands in 2 and 4 each coordinate to the single iron atom as NHC-Py chelating ligands in two basal positions and the NHCdiPic ligand of complex 3 lies in an apical position as a monodentate ligand. The large ranges of the highest and the lowest nu(CO) frequencies of 2 and 4 reflect that the relatively uneven electron density on the two iron atoms of the 2Fe2S model complexes 2 and 4 is as that observed for mono-substituted diiron complexes of good donor ligands. The cyclic voltammograms and the electrochemical proton reduction by 2 and 3 were studied in the presence of HOAc to evaluate the effect of asymmetrical substitution of strong donor ligands on the redox properties of the iron atoms and on the electrocatalytic activity for proton reduction.
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| 10. |
- Li, Fei, et al.
(författare)
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Iron(III) complexes with a tripodal N3O ligand containing an internal base as a model for catechol intradiol-cleaving dioxygenases
- 2007
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Ingår i: Inorganic Chemistry. - : American Chemical Society (ACS). - 0020-1669 .- 1520-510X. ; 46:22, s. 9364-9371
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Tidskriftsartikel (refereegranskat)abstract
- A bis(mu-alkoxo)-bridged dinuclear iron(III) complex [Fe(L)(NO3)](2)(NO3)(2) [1; HL = NN-bis(2-pyridylmethyl)-N-(2hydroxyethyl)amine] of the tripodal N3O ligand was prepared as a biomimetic model for the intradiol-cleaving dioxygenase enzymes. The reaction of 1 and catechol in the presence of excess triethylamine gave the catecholate (CAT) chelate b is(u -al koxo) -bridged dinuclear iron(Ill) complex [Fe(L)(CAT)12 (2). The molecular structures of complexes 1 and 2 were determined by X-ray crystallography. Diiron complexes 1 and 2 contain the same bis(u-alkoxo)diiron diamond core. All heteroatoms (N3O) of the ligand are coordinated to the iron center in complex 1 with two pyridine nitrogen atoms on the axial bonds, while one of the pyridyl arms of the ligand is left uncoordinated in complex 2. The interaction of the diiron complex 1 and 3,5-di-tert-butylcatechol (H2DBC) was investigated by electronic and mass spectroscopy. Complex 1 displays the intradiol-cleaving dioxygenase activity, and the coordinate ethoxyl arm of the ligand is capable of accepting the proton from catechol, which mimics the function of Tyr447 in the. protocatechuate 3,4-dioxygenase as an internal base. The spectrop h oto metric titration experiment indicates the relatively low demand of the external base (0.8 equiv based on Fe3+) for attaining the highest dioxygenase activity of complex 1. The reaction rate of the reactive intermediate [Fe(HL)(DBC)](+) with dioxygen is 0.38 M-1 s(-1) determined by kinetic studies.
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