| 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. |
- Zhang, Li-Fang, et al.
(författare)
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Proteomic analysis of plasma membranes of cyanobacterium Synechocystis sp. Strain PCC 6803 in response to high pH stress.
- 2009
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Ingår i: Journal of Proteome Research. - Washington, D.C. : American chemical society. - 1535-3893 .- 1535-3907. ; 8:6, s. 2892-902
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Tidskriftsartikel (refereegranskat)abstract
- Cyanobacteria are unique prokaryotes possessing plasma-, outer- and thylakoid membranes. The plasma membrane of a cyanobacterial cell serves as a crucial barrier against its environment and is essential for biogenesis of cyanobacterial photosystems. Previously, we have identified 79 different proteins in the plasma membrane of Synechocystis sp. Strain PCC 6803 based on 2D- and 1D- gels and MALDI-TOF MS. In this work, we have performed a proteomic study screening for high-pH-stress proteins in Synechocystis. 2-D gel profiles of plasma membranes isolated from both control and high pH-treated cells were constructed and compared quantitatively based on different protein staining methods including DIGE analysis. A total of 55 differentially expressed protein spots were identified using MALDI-TOF MS and MALDI-TOF/TOF MS, corresponding to 39 gene products. Twenty-five proteins were enhanced/induced and 14 reduced by high pH. One-third of the enhanced/induced proteins were transport and binding proteins of ABC transporters including 3 phosphate transport proteins. Other proteins include MinD involved in cell division, Cya2 in signaling and proteins involved in photosynthesis and respiration. Furthermore, among these proteins regulated by high pH, eight were found to be hypothetical proteins. Functional significance of the high-pH-stress proteins is discussed integrating current knowledge on cyanobacterial cell physiology.
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| 3. |
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| 4. |
- Huang, Fang, et al.
(författare)
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Measurement of interfiber friction force for pulp fibers by atomic force microscopy
- 2009
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Ingår i: Journal of Materials Science. - : Springer Science and Business Media LLC. - 0022-2461 .- 1573-4803. ; 44:14, s. 3770-3776
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Tidskriftsartikel (refereegranskat)abstract
- Interfiber friction in paper exists in fiber suspensions, fiber flocs, and fiber networks. The interfiber friction force is, therefore, important both in papermaking and in the use of paper. The objective of this research is to develop a methodology using atomic force microscopy (AFM) for the direct measurement of the friction force between pulp fibers. Different factors such as AFM scanning velocity, contact area, and fiber surface roughness were investigated. The results show that AFM is an effective tool for measuring micro-scale interfiber friction forces. Both AFM scanning velocity and fiber surface roughness affect the measured results. The coefficient of friction increases, but the initial adhesion force decreases, with increasing fiber surface roughness.
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| 9. |
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| 11. |
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| 12. |
- Li, Zhipeng, et al.
(författare)
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Directional Light Emission from Propagating Surface Plasmons of Silver Nanowires.
- 2009
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Ingår i: Nano Letters. - : American Chemical Society (ACS). - 1530-6992 .- 1530-6984. ; 9:Online September 21, 2009, s. 4383-4386
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Tidskriftsartikel (refereegranskat)abstract
- Thin metallic nanowires are highly promising candidates for plasmonic waveguides in photonic and electronic devices. We have observed that light from the end of a silver nanowire, following excitation of plasmons at the other end of the wire, is emitted in a cone of angles peaking at nominally 45-60 degrees from the nanowire axis, with virtually no light emitted along the direction of the nanowire. This surprising characteristic can be explained in a simple picture invoking Fabry-Perot resonances of the forward- and back-propagating plasmons on the nanowire. This strongly angular-dependent emission is a critical property that must be considered when designing coupled nanowire-based photonic devices and systems.
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| 13. |
- Morfini, Gerardo A, et al.
(författare)
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Pathogenic huntingtin inhibits fast axonal transport by activating JNK3 and phosphorylating kinesin
- 2009
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Ingår i: Nature Neuroscience. - : Nature Publishing Group. - 1097-6256 .- 1546-1726. ; 12:7, s. 864-871
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Tidskriftsartikel (refereegranskat)abstract
- Selected vulnerability of neurons in Huntington's disease suggests that alterations occur in a cellular process that is particularly critical for neuronal function. Supporting this idea, pathogenic Htt (polyQ-Htt) inhibits fast axonal transport (FAT) in various cellular and animal models of Huntington's disease (mouse and squid), but the molecular basis of this effect remains unknown. We found that polyQ-Htt inhibited FAT through a mechanism involving activation of axonal cJun N-terminal kinase (JNK). Accordingly, we observed increased activation of JNK in vivo in cellular and mouse models of Huntington's disease. Additional experiments indicated that the effects of polyQ-Htt on FAT were mediated by neuron-specific JNK3 and not by ubiquitously expressed JNK1, providing a molecular basis for neuron-specific pathology in Huntington's disease. Mass spectrometry identified a residue in the kinesin-1 motor domain that was phosphorylated by JNK3 and this modification reduced kinesin-1 binding to microtubules. These data identify JNK3 as a critical mediator of polyQ-Htt toxicity and provide a molecular basis for polyQ-Htt–induced inhibition of FAT.
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| 14. |
- Rajalahti, Tarja, et al.
(författare)
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Proteins in different Synechocystis compartments have distinguishing N-terminal features : a combined proteomics and multivariate sequence analysis
- 2007
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Ingår i: Journal of Proteome Research. - : American Chemical Society (ACS). - 1535-3893 .- 1535-3907. ; 6:7, s. 2420-2434
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Tidskriftsartikel (refereegranskat)abstract
- Cyanobacteria have a cell envelope consisting of a plasma membrane, a periplasmic space with a peptidoglycan layer, and an outer membrane. A third, separate membrane system, the intracellular thylakoid membranes, is the site for both photosynthesis and respiration. All membranes and luminal spaces have unique protein compositions, which impose an intriguing mechanism for protein sorting of extracytoplasmic proteins due to single sets of translocation protein genes. It is shown here by multivariate sequence analyses of many experimentally identified proteins in Synechocystis, that proteins routed for the different extracytosolic compartments have correspondingly different physicochemical properties in their signal peptide and mature N-terminal segments. The full-length mature sequences contain less significant information. From these multivariate, N-terminal property-profile models for proteins with single experimental localization, proteins with ambiguous localization could, to a large extent, be predicted to a defined compartment. The sequence properties involve amino acids varying especially in volume and polarizability and at certain positions in the sequence segments, in a manner typical for the various compartment classes. Potential means of the cell to recognize the property features are discussed, involving the translocation channels and two Type I signal peptidases with different cellular localization, and charge features at their membrane interfaces.
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| 15. |
- Ran, Liang, et al.
(författare)
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Proteomic analyses of the photoauto- and diazotrophically grown cyanobacterium Nostoc sp. PCC 73102
- 2007
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Ingår i: Microbiology. - : Microbiology Society. - 1350-0872 .- 1465-2080. ; 153, s. 608-618
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Tidskriftsartikel (refereegranskat)abstract
- The filamentous cyanobacteria of the genus Nostoc are globally distributed, phenotypically complex organisms, capable of cellular differentiation and of forming symbiotic associations with a wide range of plants. To further our understanding of these processes and functions, the proteome of photoautotrophically and diazotrophically grown Nostoc sp. PCC 73102 (N. punctiforme) cells was examined. Extracted proteins were separated into membrane and soluble protein fractions and analysed using two-dimensional gel electrophoresis and matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS). The analysis led to the identification of 82 proteins that could be divided into 12 functional categories. Significantly, 65 of these proteins have not been previously documented in the Nostoc proteome. Many of the proteins identified were readily recognized as housekeeping proteins involved in carbon, nitrogen and energy metabolism, but a number of proteins related to stress, motility, secretion and post-translational modifications were also identified. Ten unclassified proteins were also detected, representing potential novel functions. These proteins were highly expressed, suggesting that they play key roles during photoautotrophic and diazotrophic growth. Nineteen of the proteins expressed under the growth conditions examined contained putative thioredoxin (Trx) targets, a motif that functions in redox regulation via redox equivalent mediators and is known to be significant in a wide range of biological processes. These observations contribute to our understanding of the complex Nostoc life cycle.
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| 16. |
- Shieh, Jia-Min, et al.
(författare)
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Enhanced photoresponse of a metal-oxide-semiconductor photodetector with silicon nanocrystals embedded in the oxide layer
- 2007
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Ingår i: Applied Physics Letters. - : American Institute of Physics. - 0003-6951 .- 1077-3118. ; 90:5
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Tidskriftsartikel (refereegranskat)abstract
- The authors report a two-terminal metal-oxide-semiconductor photodetector for which light is absorbed in a capping layer of silicon nanocrystals embedded in a mesoporous silica matrix on p-type silicon substrates. Operated at reverse bias, enhanced photoresponse from 300 to 700 nm was observed. The highest optoelectronic conversion efficiency is as high as 200%. The enhancements were explained by a transistorlike mechanism, in which the inversion layer acts as the emitter and trapped positive charges in the mesoporous dielectric layer assist carrier injection from the inversion layer to the contact, such that the primary photocurrent could be amplified.
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| 17. |
- Smith, Pete, et al.
(författare)
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Sectoral approaches to improve regional carbon budgets
- 2008
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Ingår i: Climatic Change. - : Springer Science and Business Media LLC. - 0165-0009 .- 1573-1480. ; 88:3-4, s. 209-249
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Forskningsöversikt (refereegranskat)abstract
- Humans utilise about 40% of the earth's net primary production (NPP) but the products of this NPP are often managed by different sectors, with timber and forest products managed by the forestry sector and food and fibre products from croplands and grasslands managed by the agricultural sector. Other significant anthropogenic impacts on the global carbon cycle include human utilization of fossil fuels and impacts on less intensively managed systems such as peatlands, wetlands and permafrost. A great deal of knowledge, expertise and data is available within each sector. We describe the contribution of sectoral carbon budgets to our understanding of the global carbon cycle. Whilst many sectors exhibit similarities for carbon budgeting, some key differences arise due to differences in goods and services provided, ecology, management practices used, land-management personnel responsible, policies affecting land management, data types and availability, and the drivers of change. We review the methods and data sources available for assessing sectoral carbon budgets, and describe some of key data limitations and uncertainties for each sector in different regions of the world. We identify the main gaps in our knowledge/data, show that coverage is better for the developed world for most sectors, and suggest how sectoral carbon budgets could be improved in the future. Research priorities include the development of shared protocols through site networks, a move to full carbon accounting within sectors, and the assessment of full greenhouse gas budgets.
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| 18. |
- Yin, D., et al.
(författare)
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Utility based query dissemination in spatial data grid
- 2007
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Ingår i: Proceedings of the 6th International Conference on Grid and Cooperative Computing, GCC 2007. - : IEEE Computer Society. - 0769528716 - 9780769528717 ; , s. 574-581
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Konferensbidrag (refereegranskat)abstract
- Spatial Information Grid is an ideal infrastructure to handle the data-intensive and computing-intensive geo-spatial processing. In order that each agency could ad hoc connect to this computing environment and make autonomous decision, we build a Geospatial Data Grid in peer-to-peer way. The query processor module in each peer can decompose the user's query into sub-queries that executed in different nodes. One problem in the parallel spatial join query optimization is how to determine an appropriate node group to disseminate the sub-queries. Especially, if there is more than one node sharing the same area of interest, there is a dilemma: on the one hand, the task scheduler tends to decompose this query into sub-queries and disseminate them to as many as possible nodes so that they could process the user's query in parallel; on the other hand, recruiting too many nodes will also bring in overhead in repetitive computing, redundant data transmission, and the result merging. Based on the study of trade-off between increasing parallelism and reducing redundancy using the Utility Theory in economics, we put forward a fast node selection algorithm for the parallel spatial join query dissemination. The test in our system shows this strategy could balance the above two conflict demands and is appropriate for use in Data Grid.
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