| 1. |
- Connor, K. M., et al.
(författare)
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Increased dietary intake of omega-3-polyunsaturated fatty acids reduces pathological retinal angiogenesis
- 2007
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Ingår i: Nat Med. - 1078-8956.
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Tidskriftsartikel (refereegranskat)abstract
- Many sight-threatening diseases have two critical phases, vessel loss followed by hypoxia-driven destructive neovascularization. These diseases include retinopathy of prematurity and diabetic retinopathy, leading causes of blindness in childhood and middle age affecting over 4 million people in the United States. We studied the influence of omega-3- and omega-6-polyunsaturated fatty acids (PUFAs) on vascular loss, vascular regrowth after injury, and hypoxia-induced pathological neovascularization in a mouse model of oxygen-induced retinopathy. We show that increasing omega-3-PUFA tissue levels by dietary or genetic means decreased the avascular area of the retina by increasing vessel regrowth after injury, thereby reducing the hypoxic stimulus for neovascularization. The bioactive omega-3-PUFA-derived mediators neuroprotectinD1, resolvinD1 and resolvinE1 also potently protected against neovascularization. The protective effect of omega-3-PUFAs and their bioactive metabolites was mediated, in part, through suppression of tumor necrosis factor-alpha. This inflammatory cytokine was found in a subset of microglia that was closely associated with retinal vessels. These findings indicate that increasing the sources of omega-3-PUFA or their bioactive products reduces pathological angiogenesis. Western diets are often deficient in omega-3-PUFA, and premature infants lack the important transfer from the mother to the infant of omega-3-PUFA that normally occurs in the third trimester of pregnancy. Supplementing omega-3-PUFA intake may be of benefit in preventing retinopathy.
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| 2. |
- Luo, J.L, et al.
(författare)
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Impact of diagenesis on reservoir-quality evolution in fluvial and lacustrine-deltaic sandstones: evidence from Jurassic and Triassic sandstones from the Ordos Basin, China
- 2009
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Ingår i: Journal of Petroleum Geology. - : Wiley. - 0141-6421 .- 1747-5457. ; 32:1, s. 79-102
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Tidskriftsartikel (refereegranskat)abstract
- The reservoir quality of Jurassic and Triassic fluvial and lacustrine-deltaic sandstones in the intracratonic Ordos Basin is strongly influenced by depositional facies and various types of diagenetic modifications. The fluvial sandstones have higher average He-porosity and permeability (14.8% and 12.7 mD, respectively) than the deltaic sandstones (9.8% and 5.8 mD, respectively). In addition to extensive mechanical compaction, eodiagenesis (220-97 Ma; depth < 2000 m; T < 70 degrees C) has resulted in dissolution and kaolinitization of detrital silicates in the Jurassic fluvial sandstones, and in smectite infiltration and minor cementation by calcite and siderite in the Triassic fluvial and deltaic sandstones. Pervasive eogenetic carbonate cementation (> 20 vol.%) occurred in Triassic deltaic siltstones and very fine-grained sandstones which are closely associated with organic-rich mudstones. Mesodiagenesis (97-65 Ma), which occurred during rapid subsidence to depths of 3700-4400 m, resulted in the albitization of plagioclase, checmical compaction, the conversion of kaolinite into dickite, and cementation by quartz overgrowths, chlorite, illite, ankerite (delta C-13(VPDB) = -2.4 parts per thousand to +2.6 parts per thousand; delta O-18(VPDB) = -21.5 parts per thousand to -10 parts per thousand) and calcite (delta C-13(VPDB) = -4.7 parts per thousand to +3.7 parts per thousand; delta O-18(VPDB) = -21.8 parts per thousand to -13.4 parts per thousand). Oil emplacement (95 Ma) retarded cementation by mesogenetic quartz and carbonate but had little influence on dickite, illite and chlorite formation. Retardation of quartz cementation was also due to the presence of chlorite fringes around detrital quartz grains. Dickitization of eogenetic kaolinite together with the short residence time at maximum burial temperatures (105-124 degrees C) has retarded the albitization of K-feldspars and illite formation and hence prevented severe permeability destruction. Telodiagenesis, which occurred after uplift (Eocene to end-Neogene), caused slight dissolution and kaolinitization of feldspars. This study demonstrates that despite complex patterns of diagenetic modifications in the Triassic and Jurassic successions, depositional porosity and permeability are better preserved in fluvial meandering channel sandstones than in deltaic sandstones. These results should be important for modelling of reservoir-quality distribution and exploration risk evaluation in the basin.
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| 3. |
- Salem, MA, et al.
(författare)
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Atomic force microscope current-imaging study for current density through nanocrystalline silicon dots embedded in SiO2
- 2005
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Ingår i: Japanese Journal of Applied Physics. - : Japan Society of Applied Physics / Japanese Journal of Applied Physics; 1999. - 0021-4922 .- 1347-4065. ; 44:07-Jan, s. L88-L91
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Tidskriftsartikel (refereegranskat)abstract
- Simultaneous surface and current imaging through nanocrystalline silicon (nc-Si) dots embedded in SiO2 was achieved using a contact mode atomic force microscope (AFM) under a tip-to-sample bias voltages of about 5 V. The obtained images were then analyzed using a one-dimensional model of current density, which took account of the spherical shape of the nc-Si dots, the substrate orientation and the sample bias. A comparison between the experimental and theoretical results showed a fair agreement when the current pass through the dot center, although a large difference was found at a higher voltage. In addition, our model predicted tunneling current oscillations due to a change in tip position relative to the dot center.
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