| 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. |
- Chen, D. R., et al.
(författare)
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Band-rejection fiber filter and fiber sensor based on a Bragg fiber of transversal resonant structure
- 2008
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Ingår i: Optics Express. - 1094-4087. ; 16:21, s. 16489-16495
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Tidskriftsartikel (refereegranskat)abstract
- We propose a novel band-rejection fiber filter based on a Bragg fiber of transversal resonant structure, which can also be used as a fiber sensor. Defect layers are introduced in the periodic high/low index structure in the cladding of the Bragg fiber. Coupling between the core mode and the defect mode results in large confinement loss for some resonant wavelengths inside the band gap of the Bragg fiber. A segment of the Bragg fiber of transversal resonant structure can be used as a band-rejection fiber filter, whose characteristics are mainly determined by the defect layer. The loss peak wavelength of the Bragg fiber is dependent on the refractive index and the thickness of the defect layer which indicates its applications of refractive index and strain sensing.
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| 3. |
- Yang, T, et al.
(författare)
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Fe5O5[B6O10(OH)3]·nH2O: Wave-layered Iron Borate and Frustrated Antiferromagnetism
- 2009
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Ingår i: Inorganic Chemistry. - : American Chemical Society (ACS). - 0020-1669 .- 1520-510X. ; 48:23, s. 11209-11214
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Tidskriftsartikel (refereegranskat)abstract
- The first layered iron borate, Fe5O5[B6O10(OH)3]·nH2O, has been prepared by the boric acid flux method. Its structure, determined by single crystal X-ray diffraction, contains a double FeO6-octahedral layer and an unusual [B6O13] chain. The rigid and cambered [B6O13] chains bend the octahedral layers, resulting in a wave-like and sandwiched structure. Crystallographic study indicates the structural modulation is mainly from the [B6O13] chains because of the insertion of water molecules in between. Nevertheless, FeO6 layers in the average structure, which are well separated by borate chains, is still a reasonable model to understand the two-dimensional magnetism. The strong antiferromagnetic interactions and the complex Fe3+-net suggest a possible geometrically magnetic frustration, which may be the reason for the second-order temperature-induced magnetic transition at 125 K. The condensed Fe3+ layers and the relatively low redox potential at about 1.25 V versus Li+/Li show its potentials as an anodic material.
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| 4. |
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| 5. |
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| 6. |
- Fagman, Henrik, 1975, et al.
(författare)
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The 22q11 deletion syndrome candidate gene Tbx1 determines thyroid size and positioning.
- 2007
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Ingår i: Human molecular genetics. - : Oxford University Press (OUP). - 0964-6906 .- 1460-2083. ; 16:3, s. 276-85
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Tidskriftsartikel (refereegranskat)abstract
- Thyroid dysgenesis is the major cause of congenital hypothyroidism in humans. The underlying molecular mechanism is in most cases unknown, but the frequent co-incidence of cardiac anomalies suggests that the thyroid morphogenetic process may depend on proper cardiovascular development. The T-box transcription factor TBX1, which is the most probable gene for the 22q11 deletion syndrome (22q11DS/DiGeorge syndrome/velo-cardio-facial syndrome), has emerged as a central player in the coordinated formation of organs and tissues derived from the pharyngeal apparatus and the adjacent secondary heart field from which the cardiac outflow tract derives. Here, we show that Tbx1 impacts greatly on the developing thyroid gland, although it cannot be detected in the thyroid primordium at any embryonic stage. Specifically, in Tbx1-/- mice, the downward translocation of Titf1/Nkx2.1-expressing thyroid progenitor cells is much delayed. In late mutant embryos, the thyroid fails to form symmetric lobes but persists as a single mass approximately one-fourth of the normal size. The hypoplastic gland mostly attains a unilateral position resembling thyroid hemiagenesis. The data further suggest that failure of the thyroid primordium to re-establish contact with the aortic sac is a key abnormality preventing normal growth of the midline anlage along the third pharyngeal arch arteries. In normal development, this interaction may be facilitated by Tbx1-expressing mesenchyme filling the gap between the pharyngeal endoderm and the detached thyroid primordium. The findings indicate that Tbx1 regulates intermediate steps of thyroid development by a non-cell-autonomous mechanism. Thyroid dysgenesis related to Tbx1 inactivation may explain an overrepresentation of hypothyroidism occurring in patients with the 22q11DS.
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| 7. |
- Kashyap, Vasundhra, et al.
(författare)
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Regulation of Stem Cell Pluripotency and Differentiation Involves a Mutual Regulatory Circuit of the Nanog, OCT4, and SOX2 Pluripotency Transcription Factors With Polycomb Repressive Complexes and Stem Cell microRNAs
- 2009
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Ingår i: Stem Cells and Development. - : Mary Ann Liebert. - 1547-3287 .- 1557-8534. ; 18:7, s. 1093-1108
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Forskningsöversikt (refereegranskat)abstract
- Coordinated transcription factor networks have emerged as the master regulatory mechanisms of stem cell pluripotency and differentiation. Many stem cell-specific transcription factors, including the pluripotency transcription factors, OCT4, NANOG, and SOX2 function in combinatorial complexes to regulate the expression of loci, which are involved in embryonic stem (ES) cell pluripotency and cellular differentiation. This review will address how these pathways form a reciprocal regulatory circuit whereby the equilibrium between stem cell self-renewal, proliferation, and differentiation is in perpetual balance. We will discuss how distinct epigenetic repressive pathways involving polycomb complexes, DNA methylation, and microRNAs cooperate to reduce transcriptional noise and to prevent stochastic and aberrant induction of differentiation. We will provide a brief overview of how these networks cooperate to modulate differentiation along hematopoietic and neuronal lineages. Finally, we will describe how aberrant functioning of components of the stem cell regulatory network may contribute to malignant transformation of adult stem cells and the establishment of a "cancer stem cell" phenotype and thereby underlie multiple types of human malignancies.
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| 8. |
- Kim, Do Kyung, et al.
(författare)
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Monodispersed Fe-Pt nanoparticles for biomedical applications
- 2005
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 97:10, s. 10Q918-
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Tidskriftsartikel (refereegranskat)abstract
- Monodispersed Fe-Pt nanoparticles are promising candidates for biomedical applications with an average particle diameter of 6.9 nm Fe48Pt52, 3.3 nm Fe52Pt48, and 4.2 nm Fe70Pt30. They are prepared by simultaneous chemical reduction of Pt(acac)(2) and thermal decomposition of Fe(CO)(5) in the presence of surfactant as an anti-oxidation reagent and amine as a stabilizer. The blocking temperatures, T-b, of 9 K for Fe70Pt30, 11 K for Fe52Pt48 and 14.4 K for Fe48Pt52 and the mean diameter of the spherical magnetic particles were estimated from the calculated volume to be 3.6, 3.1, and 3.8 nm. The cytotoxicity of unmodified Fe-Pt nanoparticles was performed in brain endothelial cells. Fe48Pt52 nanoparticles were not found to have any significant toxicity on bEnd3 cells during a 24 h period.
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| 9. |
- Lai, I. H, et al.
(författare)
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A unique tetrameric structure of deer plasma haptoglobin – an evolutionary advantage in the Hp 2-2 phenotype with homogeneous structure
- 2008
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Ingår i: FEBS Journal. - 1742-4658 .- 1742-464X. ; 275, s. 981-993
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Tidskriftsartikel (refereegranskat)abstract
- Similar to blood types, human plasma haptoglobin (Hp) is classified intothree phenotypes: Hp 1-1, 2-1 and 2-2. They are genetically inheritedfrom two alleles Hp 1 and Hp 2 (represented in bold), but only theHp 1-1 phenotype is found in almost all animal species. The Hp 2-2protein consists of complicated large polymers cross-linked by a2-bsubunits or (a2-b)n (where n ‡ 3, up to 12 or more), and is associatedwith the risk of the development of diabetic, cardiovascular and inflammatorydiseases. In the present study, we found that deer plasma Hpmimics human Hp 2, containing a tandem repeat over the a-chain basedon our cloned cDNA sequence. Interestingly, the isolated deer Hp ishomogeneous and tetrameric, i.e. (a-b)4, although the locations of )SHgroups (responsible for the formation of polymers) are exactly identicalto that of human. Denaturation of deer Hp using 6 m urea under reducingconditions (143 mm b-mercaptoethanol), followed by renaturation,sustained the formation of (a-b)4, suggesting that the Hp tetramers arenot randomly assembled. Interestingly, an a-chain monoclonal antibody(W1), known to recognize both human and deer a-chains, only binds tointact human Hp polymers, but not to deer Hp tetramers. This impliesthat the epitope of the deer a-chain is no longer exposed on the surfacewhen Hp tetramers are formed. We propose that steric hindrance playsa major role in determining the polymeric formation in human and deerpolymers. Phylogenetic and immunochemical analyses revealed that theHp 2 allele of deer might have arisen at least 25 million years ago. Amechanism involved in forming Hp tetramers is proposed and discussed,and the possibility is raised that the evolved tetrameric structure of deerHp might confer a physiological advantage.
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| 10. |
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| 11. |
- Malkoch, Michael, et al.
(författare)
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Synthesis of well-defined hydrogel networks using Click chemistry
- 2006
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Ingår i: Chemical Communications. - 1359-7345 .- 1364-548X. ; :26, s. 2774-2776
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Tidskriftsartikel (refereegranskat)abstract
- New PEG-based hydrogel materials have been synthesized by Click chemistry and shown to result in well-defined networks having significantly improved mechanical properties; the selectivity of the azide/ acetylene coupling reaction also allows for the incorporation of various additives and functional groups leading to chemical tailoring of the hydrogels.
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| 12. |
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