| 1. |
- Coles, J. B., et al.
(författare)
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Bandwidth-efficient phase modulation techniques for Stimulated Brillouin Scattering suppression in fiber optic parametric amplifiers
- 2010
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Ingår i: Optics Express. - 1094-4087 .- 1094-4087. ; 18:17, s. 18138-18150
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Tidskriftsartikel (refereegranskat)abstract
- Two novel bandwidth efficient pump-dithering Stimulated Brillouin Scattering (SBS) suppression techniques are introduced. The techniques employ a frequency-hopped chirp and an RF noise source to impart phase modulation on the pumps of a two pump Fiber Optical Parametric Amplifier (FOPA). The effectiveness of the introduced techniques is confirmed by measurements of the SBS threshold increase and the associated improvements relative to the current state of the art. Additionally, the effect on the idler signal integrity is presented as measured following amplification from a two pump FOPA employing both techniques. The measured 0.8 dB penalty with pumps dithered by an RF noise source, after accruing 160ps/nm of dispersion with 38 dB conversion gain in a two-pump FOPA is the lowest reported to date.
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| 2. |
- Hua, Kuo-Tai, et al.
(författare)
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N-α-acetyltransferase 10 protein suppresses cancer cell metastasis by binding PIX proteins and inhibiting Cdc42/Rac1 activity
- 2011
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Ingår i: Cancer Cell. - : Cell Press. - 1535-6108 .- 1878-3686. ; 19:2, s. 218-231
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Tidskriftsartikel (refereegranskat)abstract
- N-α-acetyltransferase 10 protein, Naa10p, is an N-acetyltransferase known to be involved in cell cycle control. We found that Naa10p was expressed lower in varieties of malignancies with lymph node metastasis compared with non-lymph node metastasis. Higher Naa10p expression correlates the survival of lung cancer patients. Naa10p significantly suppressed migration, tumor growth, and metastasis independent of its enzymatic activity. Instead, Naa10p binds to the GIT-binding domain of PIX, thereby preventing the formation of the GIT-PIX-Paxillin complex, resulting in reduced intrinsic Cdc42/Rac1 activity and decreased cell migration. Forced expression of PIX in Naa10-transfected tumor cells restored the migration and metastasis ability. We suggest that Naa10p functions as a tumor metastasis suppressor by disrupting the migratory complex, PIX-GIT- Paxillin, in cancer cells.
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| 3. |
- Lange, Leslie A, et al.
(författare)
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Whole-Exome Sequencing Identifies Rare and Low-Frequency Coding Variants Associated with LDL Cholesterol.
- 2014
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Ingår i: American Journal of Human Genetics. - : Elsevier BV. - 0002-9297. ; 94:2, s. 233-245
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Tidskriftsartikel (refereegranskat)abstract
- Elevated low-density lipoprotein cholesterol (LDL-C) is a treatable, heritable risk factor for cardiovascular disease. Genome-wide association studies (GWASs) have identified 157 variants associated with lipid levels but are not well suited to assess the impact of rare and low-frequency variants. To determine whether rare or low-frequency coding variants are associated with LDL-C, we exome sequenced 2,005 individuals, including 554 individuals selected for extreme LDL-C (>98(th) or <2(nd) percentile). Follow-up analyses included sequencing of 1,302 additional individuals and genotype-based analysis of 52,221 individuals. We observed significant evidence of association between LDL-C and the burden of rare or low-frequency variants in PNPLA5, encoding a phospholipase-domain-containing protein, and both known and previously unidentified variants in PCSK9, LDLR and APOB, three known lipid-related genes. The effect sizes for the burden of rare variants for each associated gene were substantially higher than those observed for individual SNPs identified from GWASs. We replicated the PNPLA5 signal in an independent large-scale sequencing study of 2,084 individuals. In conclusion, this large whole-exome-sequencing study for LDL-C identified a gene not known to be implicated in LDL-C and provides unique insight into the design and analysis of similar experiments.
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| 4. |
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| 5. |
- Bartels-Rausch, T., et al.
(författare)
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A review of air-ice chemical and physical interactions (AICI): Liquids, quasi-liquids, and solids in snow
- 2014
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Ingår i: Atmospheric Chemistry And Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 14:3, s. 1587-1633
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Tidskriftsartikel (refereegranskat)abstract
- Snow in the environment acts as a host to rich chemistry and provides a matrix for physical exchange of contaminants within the ecosystem. The goal of this review is to summarise the current state of knowledge of physical processes and chemical reactivity in surface snow with relevance to polar regions. It focuses on a description of impurities in distinct compartments present in surface snow, such as snow crystals, grain boundaries, crystal surfaces, and liquid parts. It emphasises the microscopic description of the ice surface and its link with the environment. Distinct differences between the disordered air-ice interface, often termed quasi-liquid layer, and a liquid phase are highlighted. The reactivity in these different compartments of surface snow is discussed using many experimental studies, simulations, and selected snow models from the molecular to the macro-scale. Although new experimental techniques have extended our knowledge of the surface properties of ice and their impact on some single reactions and processes, others occurring on, at or within snow grains remain unquantified. The presence of liquid or liquid-like compartments either due to the formation of brine or disorder at surfaces of snow crystals below the freezing point may strongly modify reaction rates. Therefore, future experiments should include a detailed characterisation of the surface properties of the ice matrices. A further point that remains largely unresolved is the distribution of impurities between the different domains of the condensed phase inside the snowpack, i.e. in the bulk solid, in liquid at the surface or trapped in confined pockets within or between grains, or at the surface. While surface-sensitive laboratory techniques may in the future help to resolve this point for equilibrium conditions, additional uncertainty for the environmental snowpack may be caused by the highly dynamic nature of the snowpack due to the fast metamorphism occurring under certain environmental conditions. Due to these gaps in knowledge the first snow chemistry models have attempted to reproduce certain processes like the long-term incorporation of volatile compounds in snow and firn or the release of reactive species from the snowpack. Although so far none of the models offers a coupled approach of physical and chemical processes or a detailed representation of the different compartments, they have successfully been used to reproduce some field experiments. A fully coupled snow chemistry and physics model remains to be developed. © Author(s) 2014.
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| 6. |
- Chatterjee, Sanjukta, et al.
(författare)
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Mechanical reinforcement and thermal conductivity in expanded graphene nanoplatelets reinforced epoxy composites
- 2012
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Ingår i: Chemical Physics Letters. - : Elsevier BV. - 0009-2614 .- 1873-4448. ; 531, s. 6-10
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Tidskriftsartikel (refereegranskat)abstract
- Influence of reinforcements on mechanical and thermal properties of graphene nanoplatelets/epoxy composites is investigated. Amine functionalized expanded graphene nanoplatelets (EGNPs) were dispersed within epoxy resins using high-pressure processor followed by three roll milling. Functionality on the EGNPs was confirmed with FTIR and micro-Raman spectroscopy. Bending and nano-mechanical testing was performed on the composites. Incorporation of EGNPs improved the flexural modulus and hardness of the composite and increased fracture toughness by up to 60%. Marked improvement was observed in thermal conductivity of the composites reaching 36% at 2 wt.% loading. Functionalized EGNPs exhibited significant improvements indicating favorable interaction at EGNPs/polymer interface.
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| 7. |
- Curtis, Bruce A., et al.
(författare)
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Algal genomes reveal evolutionary mosaicism and the fate of nucleomorphs
- 2012
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 492:7427, s. 59-65
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Tidskriftsartikel (refereegranskat)abstract
- Cryptophyte and chlorarachniophyte algae are transitional forms in the widespread secondary endosymbiotic acquisition of photosynthesis by engulfment of eukaryotic algae. Unlike most secondary plastid-bearing algae, miniaturized versions of the endosymbiont nuclei (nucleomorphs) persist in cryptophytes and chlorarachniophytes. To determine why, and to address other fundamental questions about eukaryote-eukaryote endosymbiosis, we sequenced the nuclear genomes of the cryptophyte Guillardia theta and the chlorarachniophyte Bigelowiella natans. Both genomes have >21,000 protein genes and are intron rich, and B. natans exhibits unprecedented alternative splicing for a single-celled organism. Phylogenomic analyses and subcellular targeting predictions reveal extensive genetic and biochemical mosaicism, with both host-and endosymbiont-derived genes servicing the mitochondrion, the host cell cytosol, the plastid and the remnant endosymbiont cytosol of both algae. Mitochondrion-to-nucleus gene transfer still occurs in both organisms but plastid-to-nucleus and nucleomorph-to-nucleus transfers do not, which explains why a small residue of essential genes remains locked in each nucleomorph.
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| 8. |
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| 9. |
- Yang, S, et al.
(författare)
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Improvement of Crystalline and Photoluminescence of Atomic Layer Deposited m-Plane ZnO Epitaxial Films by Annealing Treatment
- 2012
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Ingår i: Crystal Growth & Design. - : American Chemical Society. - 1528-7483 .- 1528-7505. ; 12:10, s. 4745-4751
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Tidskriftsartikel (refereegranskat)abstract
- Monocrystalline m-plane ZnO epitaxial films with flat surface morphology were grown on m-plane sapphire by using atomic layer deposition. X-ray diffraction and transmission electron microscopy measurements verify not only the in-plane epitaxial relationship of the as-grown films as (10 (1) over bar0)andlt; 0001 andgt;(ZnO)parallel to(10 (1) over bar0)andlt;(1) over bar2 (1) over bar0 andgt; Al2O3 but also the absence of domains with undesirable orientations, which are generally obtained in the m-plane ZnO films grown by other methods. Experimental results indicate that the basal plane stacking fault (BSF) is the dominant structural defects that contribute to the emission at 3.31 eV in m-plane ZnO films. Exactly how thermal annealing affects the structural and optical properties of ZnO epi-films was also investigated. Additionally, based on time-resolved photoluminescence at 5 K, the decay time of BSF related emission and near-band-edge (NBE) emission were determined. Results of this work further demonstrated that the decay time of NBE emission increases with a higher annealing temperature, accompanied by an improvement in crystal structure.
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| 10. |
- Yang, S., et al.
(författare)
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Recombination dynamics of a localized exciton bound at basal stacking faults within the m-(p)lane ZnO film
- 2014
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Ingår i: Applied Physics Letters. - : American Institute of Physics (AIP). - 0003-6951 .- 1077-3118. ; 105:1, s. 011106-
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Tidskriftsartikel (refereegranskat)abstract
- We investigated the carrier dynamics near basal stacking faults (BSFs) in m-plane ZnO epitaxial film. The behaviors of the type-II quantum wells related to the BSFs are verified through time-resolved and time-integrated photoluminescence. The decay time of the emission of BSFs is observed to have a higher power law value and longer decay time than the emission of the donor-bound excitons. The spectral-dependent decay times reveal a phenomenon of carriers migrating among band tail states, which are related to the spatial distribution of the type-II quantum wells formed by the BSFs. A high density of excited carriers leads to a band bending effect, which in turn causes a blue-shift of the emission peak of BSFs with a broadened distribution of band tail states.
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