| 1. |
- Aulin, Tor, 1948, et al.
(författare)
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Crossover product accumulate codes
- 2008
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Ingår i: Electronics Letters. - 1350-911X .- 0013-5194. ; 44:20, s. 1211-1212
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Tidskriftsartikel (refereegranskat)abstract
- A class of turbo-like codes with a crossover component, termed crossover product accumulate (CPA) codes is proposed. This structure is a serial concatenation of a crossover parallel concatenated code and an accumulator through an interleaver. A detailed iterative decodingscheme for CPA codes is described. Simulations show that different crossover depth makes CPA codes have different convergence in bit error rate (BER) performance, and a proper crossover structure produces faster convergence.
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| 2. |
- Bexborn, Fredrik, et al.
(författare)
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The tick-over theory revisited : formation and regulation of the soluble alternative complement C3 convertase (C3(H2O)Bb)
- 2008
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Ingår i: Molecular Immunology. - : Elsevier BV. - 0161-5890 .- 1872-9142. ; 45:8, s. 2370-2379
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Tidskriftsartikel (refereegranskat)abstract
- The molecular interactions between the components of the C3 convertase of the alternative pathway (AP) of complement and its regulators, in both surface-bound and fluid-phase form, are still incompletely understood. The fact that the AP convertase is labile makes studies difficult to perform. According to the so called tick-over theory, hydrolyzed C3, called C3(H(2)O), forms the initial convertase in fluid phase together with factor B. In the present study, we have applied western blot analysis and ELISA together with fluorescence resonance energy transfer (FRET) to study the formation of the fluid-phase AP convertases C3(H(2)O)Bb and C3bBb and their regulation by factor H and factor I at specific time points and, with FRET, in real time. In our hands, factor B showed a higher affinity for C3(H(2)O) than for C3b, although in both cases it was readily activated to Bb. However, the convertase activity of C3bBb was approximately twice that of C3(H(2)O)Bb, as monitored by the generation of C3a. But in contrast, the C3(H(2)O)Bb convertase was more resistant to inactivation by factor H and factor I than was the C3bBb convertase. Under conditions that totally inactivated C3bBb, C3(H(2)O)Bb still retained approximately 25% of its initial activity.
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| 3. |
- Chen, Hui, et al.
(författare)
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Characterization of insolubilized humic acid and its sorption behaviors
- 2009
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Ingår i: Environmental Geology. - : Springer Science and Business Media LLC. - 0943-0105 .- 1432-0495. ; 57:8, s. 1847-1853
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Tidskriftsartikel (refereegranskat)abstract
- Insolubilized humic acid (IHA) was prepared in the laboratory by heating approach. Through the comparison between the endothermic peaks, optimal heating temperature was determined to be 330A degrees C. The modified IHA then was characterized by TG-DTA, SEM, FTIR, element analysis, and nitrogen adsorption-desorption isotherms. The removal efficiency of p-nitrophenol from the aqueous solution by adsorption onto solid IHA surfaces was shown to be a function of pH, reaction temperature, and p-nitrophenol concentration. Adsorption equilibrium data satisfactorily fitted the Langmuir adsorption isotherm. Under a certain concentration range, the removal rate of p-nitrophenol at pH 3.5 could reach 24, 29, and 35 mg/g at a temperature of 25, 35, and 45 +/- 0.1A degrees C. The results suggest that IHA could play a role as a potential efficient absorbent to remove organic contaminants, e.g., utilized to purify water contaminated by organic compounds.
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| 4. |
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| 5. |
- Li, Jing-Jing, et al.
(författare)
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Immobilized Triton X-100-assisted refolding of Green Fluorescent Protein-Tobacco Etch Virus protease fusion protein using β-cyclodextrin as the eluent
- 2009
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Ingår i: Process Biochemistry. - : Elsevier BV. - 1359-5113 .- 1873-3298. ; 44:3, s. 277-282
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Tidskriftsartikel (refereegranskat)abstract
- A new protein refolding technique based on the use of the non-charged detergent Triton X-100 immobilized to the cross-linked agarose gel Sepharose High Performance has been developed. The new solid phase was used in combination with soluble β-cyclodextrin (β-CD) to refold recombinant Green Fluorescent Protein fused to Tobacco Etch Virus protease (GFPTEVP) expressed as inclusion bodies in E. coli. Previous attempts to refold recombinant GFPTEVP by dilution had failed. In the new procedure a column packed with Triton X-100-coupled Sepharose High Performance was used to capture unfolded GFPTEVP followed by elution using an increasing β-CD concentration gradient. The yield of properly refolded GFPTEVP was 46% at a protein concentration of 380 μg/ml. In contrast, dilution refolding of GFPTEVP at 200 μg/ml refolding buffer resulted in only 4.7% of native protein.
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| 6. |
- Liu, Hui, et al.
(författare)
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Confinement effect on scattering states in a thin lead film: Field-induced resonance states in the high-bias regime of scanning tunneling microscopy
- 2007
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Ingår i: Physical Review B. ; 76:11
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Tidskriftsartikel (refereegranskat)abstract
- Field-induced resonance states in the high-bias regime of scanning tunneling microscopy are used to couple and probe the scattering states above the vacuum level in a thin lead film. The resonance energies show a bilayer oscillation as a function of film thickness. Theoretical modeling unveils that the oscillation results from the confinement of the highly excited scattering states by the quantum well, yielding a bilayer phase modulation at the boundaries where they are coherently coupled to the external states.
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| 7. |
- Löwemark, Ludvig, et al.
(författare)
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Glacio-eustatic influence on deep water circulation in the South China Sea over the past 500 kyrs – implications for global biogeochemical cycling
- 2008
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Ingår i: Western Pacific Geophysics Meeting, American Geophysical Union, Cairns, Australia, July/August 2008.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- We provide new evidence for the development of a stable estuarinecirculation characterized by stagnating water bodies, nutrient recycling and increased primary productivity in the South China Seaduring glacial intervals caused by the closure of the shallow andnarrow straits connecting the South China Sea in the south and west. Our main evidence comes from records of Mn concentrations and Mn/Al ratios in two sedimentary cores from the northern and southeastern South China Sea covering the last 500 ky. Concentrations and Mn/Al ratios of the redox sensitive element Mn show clear glacial-interglacial cycles with maxima during interglacial periods and minima during glacial periods. These cycles indicate ventilation cycles of the bottom water connected to the glacial-interglacial changes in sea level. In contrast, total organic carbon (TOC) concentrations display an opposite pattern with pronounced maxima during glacial times, especially in the southern part of the basin. The variations in TOC can be ascribed to two factors. Firstly to variations in primary productivity controlled by variations in theintensity of the winter monsoon. Secondly to the degree of preservation of TOC controlled by variations in ventilation, ultimately controlled by sea level. Variations in TOC consequentlyrepresent a superimposition of sea level influenced preservationcontrol and primarily winter monsoon driven variations in primaryproductivity intensity. The decrease in Mn correspond to times when sea level dropped below 40-50 m. Larger amplitude of the variations in TOC and Mn in the southern part of the basin compared to the northern sites suggest that oxygen depletion and nutrient recycling was stronger in the parts of the basin situated the furthest from the only remaining opening to the open Pacific, the Luzon strait.
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| 8. |
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| 9. |
- Orrú, Valeria, et al.
(författare)
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A loss-of-function variant of PTPN22 is associated with reduced risk of systemic lupus erythematosus
- 2009
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Ingår i: Human Molecular Genetics. - : Oxford University Press (OUP). - 0964-6906 .- 1460-2083. ; 18:3, s. 569-579
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Tidskriftsartikel (refereegranskat)abstract
- A gain-of-function R620W polymorphism in the PTPN22 gene, encoding the lymphoid tyrosine phosphatase LYP, has recently emerged as an important risk factor for human autoimmunity. Here we report that another missense substitution (R263Q) within the catalytic domain of LYP leads to reduced phosphatase activity. High-resolution structural analysis revealed the molecular basis for this loss of function. Furthermore, the Q263 variant conferred protection against human systemic lupus erythematosus, reinforcing the proposal that inhibition of LYP activity could be beneficial in human autoimmunity.
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| 10. |
- Slotte, Tanja, et al.
(författare)
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Splicing variation at a FLOWERING LOCUS C homeolog is associated with flowering time variation in the tetraploid Capsella bursa-pastoris
- 2009
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Ingår i: Genetics. - : Oxford University Press (OUP). - 0016-6731 .- 1943-2631. ; 183:1, s. 337-345
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Tidskriftsartikel (refereegranskat)abstract
- The long-term fates of duplicate genes are well studied both empirically and theoretically, but how the short-term evolution of duplicate genes contributes to phenotypic variation is less well known. Here, we have studied the genetic basis of flowering time variation in the disomic tetraploid Capsella bursa-pastoris. We sequenced four duplicate candidate genes for flowering time and 10 background loci in samples from western Eurasia and China. Using a mixed-model approach that accounts for population structure, we found that polymorphisms at one homeolog of two candidate genes, FLOWERING LOCUS C (FLC) and CRYPTOCHROME1 (CRY1), were associated with natural flowering time variation. No potentially causative polymorphisms were found in the coding region of CRY1; however, at FLC two splice site polymorphisms were associated with early flowering. Accessions harboring nonconsensus splice sites expressed an alternatively spliced transcript or did not express this FLC homeolog. Our results are consistent with the function of FLC as a major repressor of flowering in Arabidopsis thaliana and imply that nonfunctionalization of duplicate genes could provide an important source of phenotypic variation.
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