| 1. |
- Di, Jing, et al.
(författare)
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A novel composite electrolyte based on CeO2 for low temperature solid oxide fuel cells
- 2008
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Ingår i: Journal of Inorganic Materials. - 1000-324X. ; 23:3, s. 573-577
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Tidskriftsartikel (refereegranskat)abstract
- A novel composite material based on mixture of samarium-doped ceria (SDC)-carbonate was studied as electrolyte in low temperature solid oxide fuel cells. The phase and microstructures of composite electrolyte were examined by XRD and SEM. The electrical conductivity was investigated by AC impedance spectroscopy at 400-700 degrees C in different atmospheres. An abrupt change in the conductivity at about 500 degrees C indicates that different mechanisms affect transfer in different temperature ranges. The conductivity increases with the carbonate fraction above 500 degrees C. The conductivity in reduce atmosphere is higher than that in oxide atmosphere. An anode-supported fuel cell using SDC-carbonate as electrolyte was fabricated and tested. The result shows that all the composite electrolytes exhibit better performance than pure SDC electrolyte. The electrolyte with 20wt% carbonate can achieve the highest power density of 415mW center dot cm(-2) and an open circuit voltage of 1.00V at 500 degrees C.
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| 2. |
- Dogiel, Vladimir A., et al.
(författare)
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Origin of Thermal and Non-Thermal Hard X-Ray Emissionfrom the Galactic Center
- 2009
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Ingår i: Publications of the Astronomical Society of Japan. - : Oxford University Press. - 0004-6264 .- 2053-051X. ; 61:5, s. 1099-1105
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Tidskriftsartikel (refereegranskat)abstract
- We analyse new results of Chandra and Suzaku Observatories which found a flux of hard X-ray emission from the compact region around Sgr A∗ (r ∼ 100 pc). We suppose that this emission is generated by accretion processes onto the central supermassive blackhole when an unbound part of captured stars obtains an additional momentum. As a result a flux of subrelativistic protons is generated near the galactic center which heats the background plasma up to temperatures about 6–10 keV and produces by inverse bremsstrahlung a flux of non-thermal X-ray emission in the energy range above 10 keV.
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| 3. |
- Klionsky, Daniel J., et al.
(författare)
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Guidelines for the use and interpretation of assays for monitoring autophagy in higher eukaryotes
- 2008
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Ingår i: Autophagy. - : Landes Bioscience. - 1554-8627 .- 1554-8635. ; 4:2, s. 151-175
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Forskningsöversikt (refereegranskat)abstract
- Research in autophagy continues to accelerate,1 and as a result many new scientists are entering the field. Accordingly, it is important to establish a standard set of criteria for monitoring macroautophagy in different organisms. Recent reviews have described the range of assays that have been used for this purpose.2,3 There are many useful and convenient methods that can be used to monitor macroautophagy in yeast, but relatively few in other model systems, and there is much confusion regarding acceptable methods to measure macroautophagy in higher eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers of autophagosomes versus those that measure flux through the autophagy pathway; thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from fully functional autophagy that includes delivery to, and degradation within, lysosomes (in most higher eukaryotes) or the vacuole (in plants and fungi). Here, we present a set of guidelines for the selection and interpretation of the methods that can be used by investigators who are attempting to examine macroautophagy and related processes, as well as by reviewers who need to provide realistic and reasonable critiques of papers that investigate these processes. This set of guidelines is not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to verify an autophagic response.
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| 4. |
- Luo, Cheng, et al.
(författare)
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Is COX-2 a perpetrator or a protector? Selective COX-2 inhibitors remain controversial
- 2005
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Ingår i: Acta Pharmacologica Sinica. - : Springer Science and Business Media LLC. - 1671-4083 .- 1745-7254. ; 26:8, s. 926-933
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Tidskriftsartikel (refereegranskat)abstract
- COX-2(cyclooxygenase-2) has sparked a surge in pharmaceutical interest since its discovery at the beginning of the 1990s. Several COX-2 selective inhibitors that avoid gastrointestinal side effects have been successfully launched into the market in recent years. The first selective COX-2 inhibitor, celecoxib, entered the market in December 1998 [corrected] However, there are a few organs that physiologically and functionally express COX-2, particularly the glomeruli of the kidney and the cortex of the brain. Inhibition of COX-2 expression in these organs possibly causes heart attack and stroke in long-term COX-2 inhibitor users. Recently, a USA Food and Drug Agency (FDA) advisory panel re-evaluated COX-2 inhibitors and unanimously concluded that the entire class of COX-2 inhibitors increase the risk of cardiovascular problems. Thus the use of COX-2 inhibitors is still controversial, and there is a challenge for not only pharmacologists, but also the pharmaceutical industry, to develop improved painkilling and anti-inflammatory drugs. This may involve exploring a new generation of COX-2 inhibitors with different inhibitory mechanisms through computer-aided design, screening different sources of inhibitors with lower selectivity, or seeking completely new targets. Synthetic COX-2 inhibitors have high selectivity and the advantage of irreversible inhibition, whereas naturally derived COX-2 inhibitors have lower selectivity and fewer side effects, with the medical effects in general not being as striking as those achieved using synthetic inhibitors. This review discusses the mechanism of COX-2 inhibitor therapy and a possible new way of exploration in the development of anti-inflammatory, analgetic, and antipyretic drugs.
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| 5. |
- Mikkelsen, Tarjei, et al.
(författare)
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Initial sequence of the chimpanzee genome and comparison with the human genome
- 2005
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 437:7055, s. 69-87
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Tidskriftsartikel (refereegranskat)abstract
- Here we present a draft genome sequence of the common chimpanzee (Pan troglodytes). Through comparison with the human genome, we have generated a largely complete catalogue of the genetic differences that have accumulated since the human and chimpanzee species diverged from our common ancestor, constituting approximately thirty-five million single-nucleotide changes, five million insertion/deletion events, and various chromosomal rearrangements. We use this catalogue to explore the magnitude and regional variation of mutational forces shaping these two genomes, and the strength of positive and negative selection acting on their genes. In particular, we find that the patterns of evolution in human and chimpanzee protein-coding genes are highly correlated and dominated by the fixation of neutral and slightly deleterious alleles. We also use the chimpanzee genome as an outgroup to investigate human population genetics and identify signatures of selective sweeps in recent human evolution.
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