| 1. |
- Zhao, Yaofeng, et al.
(författare)
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Ornithorhynchus anatinus (Platypus) Links the Evolution of Immunoglobulin Genes in Eutherian Mammals and Nonmammalian Tetrapods
- 2009
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Ingår i: Journal of Immunology. - : The American Association of Immunologists. - 0022-1767 .- 1550-6606. ; 183:5, s. 3285-3293
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Tidskriftsartikel (refereegranskat)abstract
- The evolutionary origins of mammalian immunoglobulin H chain isotypes (IgM, IgD, IgG, IgE, and IgA) are still incompletely understood as these isotypes differ considerably in structure and number from their counterparts in nonmammalian tetrapods. We report in this study that the platypus (Ornithorhynchus anatinus) Ig H chain constant region gene locus contains eight Ig encoding genes, which are arranged in an mu-delta-o-gamma 2-gamma 1-alpha 1-epsilon-alpha 2 order, spanning a total of similar to 200 kb DNA, encoding six distinct isotypes. The o (o for Ornithorhynchus) gene encodes a novel Ig H chain isotype that consists of four constant region domains and a hinge, and is structurally different from any of the five known mammalian Ig classes. This gene is phylogenetically related to nu (epsilon) and gamma, and thus appears to be a structural intermediate between these two genes. The platypus delta gene encodes ten heavy chain constant region domains, lacks a hinge region and is similar to IgD in amphibians and fish, but strikingly different from that in eutherian mammals. The platypus Ig H chain isotype repertoire thus shows a unique combination of genes that share similarity both to those of nonmammallian tetrapods and eutherian animals and demonstrates how phylogenetically informative species can be used to reconstruct the evolutionary history of functionally important genes.
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| 2. |
- Xu, Feng, et al.
(författare)
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Broadband spectroscopic sensor for real-time monitoring of industrial SO2 emissions
- 2007
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Ingår i: Applied Optics. - 2155-3165. ; 46:13, s. 2503-2506
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Tidskriftsartikel (refereegranskat)abstract
- A spectroscopic system for continuous real-time monitoring of SO2, concentrations in industrial emissions was developed. The sensor is well suited for field applications due to simple and compact instrumental design, and robust data evaluation based on ultraviolet broadband absorption without the use of any calibration cell. The sensor has a detection limit of 1 ppm, and was employed both for gas-flow simulations with and without suspended particles, and for in situ measurement of SO2 concentrations in the flue gas emitted from an industrial coal-fired boiler. The price/performance ratio of the instrument is expected to be superior to other comparable real-time monitoring systems.
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| 3. |
- Chen, Guanying, et al.
(författare)
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Near vacuum ultraviolet luminescence of Gd3+ and Er3+ ions generated by super saturation upconversion processes
- 2009
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Ingår i: Optics Express. - 1094-4087. ; 17:19, s. 16366-16371
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Tidskriftsartikel (refereegranskat)abstract
- Near vacuum ultraviolet (UV) upconversion (UC) emissions with a spectral resolution of 1 nm, from the (6)G(J), D-6(J), I-6(J), P-6(J) levels of Gd3+ and the L-2(17/2), D-4(7/2), H-2(2)(9/2), D-2(5/2), (4)G(7/2), K-2(13/2), P-2(3/2) levels of Er3+, were observed under 974 nm laser excitation. Mechanism analyses illustrate that successive energy transfers (ETs) from Yb3+ to Er3+ generate UV UC radiations in Er3+, while two resonant ETs from Er3+ to Gd3+ lead to UV UC radiations in Gd3+. Power dependence analyses indicate that the expected inefficient four- and five-photon processes have been switched into efficient two-photon processes due to a super saturation UC phenomenon that employs consecutive saturations at the intermediate states. (C) 2009 Optical Society of America
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| 4. |
- Liu, Zhidan, et al.
(författare)
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A novel configuration of microbial fuel cell stack bridged internally through an extra cation exchange membrane.
- 2008
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Ingår i: Biotechnology Letters. - : Springer Science and Business Media LLC. - 1573-6776 .- 0141-5492. ; 30, s. 1017-1023
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Tidskriftsartikel (refereegranskat)abstract
- This paper reports a novel configuration of stacked microbial fuel cells (MFCs) bridged internally through an extra cation exchange membrane (CEM). The MFC stack (MFC(stack)), assembled from two single MFCs (MFC(single)), resulted in double voltage output and half optimal external resistance. COD removal rate was increased from 32.4% to 54.5%. The performance improvement could be attributed to the smaller internal resistance and enhanced cations transfer. A result from a half cell study further confirmed the important role of the extra CEM. This study also demonstrated MFCs where the anode and cathode were sandwiched between two CEMs possessed significantly high power outputs.
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| 5. |
- Liu, Zhidan, et al.
(författare)
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Study of operational performance and electrical response on mediator-less microbial fuel cells fed with carbon- and protein-rich substrates
- 2009
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Ingår i: Biochemical Engineering Journal. - : Elsevier BV. - 1369-703X. ; 45:3, s. 185-191
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Tidskriftsartikel (refereegranskat)abstract
- The inducement of electroactive consortia was carried Out in dual-chamber MFCS using acetate-based substrate- and a protein-rich synthetic wastewater in fed-batch mode. The characteristics of these MFCs were then compared. MFCs based on acetate-induced consortia (MFCAce) achieved more than twice higher maximum power, and one half of optimal external resistance in comparison to MFCs based on consortia (MFCPro) induced by a protein-rich wastewater. Furthermore, these MFCs exhibited various electrical responses even identical Substrate being applied. MFCAce preferred carbon-neutral substrates. whereas MFCPro exhibited better performance on nitrogen rich feedstock. In particular, for glucose-glutamic acid solution with gradually decreased glucose/glutamic acid ratio, MFCPro exhibited increasing electrical responses than MFCAce. These results suggest that it is possible to optimize the behavior and characteristics of MFC through proper selection of feeding substrate. (C) 2009 Elsevier B.V. All rights reserved.
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| 6. |
- Lou, Xiutao, et al.
(författare)
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Gas detection by correlation spectroscopy employing a multimode diode laser
- 2008
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Ingår i: Applied Optics. - 2155-3165. ; 47:13, s. 2392-2398
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Tidskriftsartikel (refereegranskat)abstract
- A gas sensor based on the gas-correlation technique has been developed using a multimode diode laser (MDL) in a dual-beam detection scheme. Measurement of CO2 mixed with CO as an interfering gas is successfully demonstrated using a 1570 run tunable MDL. Despite overlapping absorption spectra and occasional mode hops, the interfering signals can be effectively excluded by a statistical procedure including correlation analysis and outlier identification. The gas concentration is retrieved from several pair-correlated signals by a linear-regression scheme, yielding a reliable and accurate measurement. This demonstrates the utility of the unsophisticated MDLs as novel light sources for gas detection applications.
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| 7. |
- Lou, Xiutao, et al.
(författare)
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Oxygen measurement by multimode diode lasers employing gas correlation spectroscopy
- 2009
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Ingår i: Applied Optics. - 2155-3165. ; 48:5, s. 990-997
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Tidskriftsartikel (refereegranskat)abstract
- Multimode diode laser (MDL)-based correlation spectroscopy (COSPEC) was used to measure oxygen in ambient air, thereby employing a diode laser (DL) having an emission spectrum that overlaps the oxygen absorption lines of the A band. A sensitivity of 700 ppm m was achieved with good accuracy (2%) and linearity (R-2 = 0.999). For comparison, measurements of ambient oxygen were also performed by tunable DL absorption spectroscopy (TDLAS) technique employing a vertical cavity surface emitting laser. We demonstrate that, despite slightly degraded sensitivity, the MDL-based COSPEC-based oxygen sensor has the advantages of high stability, low cost, ease-of-use, and relaxed requirements in component selection and instrument buildup compared with the TDLAS-based instrument. (C) 2009 Optical Society of America
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| 8. |
- Xu, Can, et al.
(författare)
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Autofluorescence insensitive imaging using upconverting nanocrystals in scattering media
- 2008
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 93:17
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Tidskriftsartikel (refereegranskat)abstract
- Autofluorescence is a nuisance in the field of fluorescence imaging and tomography of exogenous molecular markers in tissue, degrading the quality of the collected data. In this letter, we report autofluorescence insensitive imaging using highly efficient upconverting nanocrystals (NaYF4: Yb3+ /Tm3+) in a tissue phantom illuminated with near- infrared radiation of 85 mW/cm(2). It was found that imaging with such nanocrystals leads to an exceptionally high contrast compared to traditional downconverting fluorophores due to the absence of autofluorescence. Upconverting nanocrystals may be envisaged as important biological markers for tissue imaging purposes. c 2008 American Institute of Physics. [DOI: 10.1063/1.3005588]
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| 9. |
- Zhou, Weibin, et al.
(författare)
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Ion-exchange chromatography of hepatitis B virus surface antigen from a recombinant Chinese hamster ovary cell line
- 2005
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Ingår i: Journal of Chromatography A. ; 1095:1-2, s. 119-125
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Tidskriftsartikel (refereegranskat)abstract
- About 10% of the Chinese population are chronic carriers of hepatitis B virus (HBV). Thus, the development of a highly efficient process for the preparation of a vaccine based on a recombinant hepatitis B surface antigen (HBsAg) is very important to the Chinese national immunization program. To this end, the ion exchange chromatography recovery of CHO-HBsAg from a recombinant Chinese hamster ovary cell line was shown to increase from about 55 to 80% by the addition of 1% poly(ethylene glycol) (PEG 10,000) to the mobile phase. Furthermore, based on analysis by sodium dodecyl sulphate–polyacrylamide gel electrophoresis (SDS-PAGE), the intact glycoprotein form of CHO-HBsAg was completely preserved by the addition of PEG. In the absence of PEG the glycoprotein form of CHO-HBsAg was also spread out into the high salt elution fraction. High-performance size-exclusion chromatography with on-line multiangle-laser-light scattering (HPSEC-MALLS) analysis was performed to monitor the status of the CHO-HBsAg aggregate structure assembly, particle size and molecular weight distribution after each purification step, and the results showed further that the presence of PEG facilitated the separation and recovery of intact glycoprotein form of CHO-HBsAg and promoted their assembly to proper virus-like particles, which are both important features and prerequisites of their immunogenicity.
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| 10. |
- Zhou, Weibin, et al.
(författare)
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Molecular characterization of recombinant Hepatitis B surface antigen from Chinese hamster ovary and Hansenula polymorpha cells by high-performance size exclusion chromatography and multi-angle laser light scattering
- 2006
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Ingår i: Journal of chromatography. B. - : Elsevier BV. - 1570-0232 .- 1873-376X. ; 838:2, s. 71-77
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Tidskriftsartikel (refereegranskat)abstract
- The molecular weight and size of recombinant Hepatitis B surface antigen (HBsAg) derived from Chinese hamster ovary (CHO) and the Hansenula polymorph have been characterized by high-performance size exclusion chromatography with multi-angle laser light scattering (HPSEC-MALLS). The average molecular weight of CHO-derived HBsAg particle (CHO-rHBsAg) (4921 kDa) was higher than that of H. polymorpha yeast strain (Hans-rHBsAg) (3010 kDa). The size of CHO-rHBsAg (22.1 nm) is nearly the same as that of native HBsAg compared to 18.1 nm for Hans-rHBsAg. The average monomer numbers were found to be 155 for CHO-rHBsAg and 86 for Hans-rHBsAg, respectively. The data obtained support the assumption that the higher immunogenicity of CHO-derived HBsAg is related to its more favorable macromolecular assembly structure.
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