| 1. |
- Li, H. N., et al.
(författare)
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Electronic structure of Yb2.75C60
- 2003
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 68:16
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Tidskriftsartikel (refereegranskat)
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| 2. |
- Bergström, A., et al.
(författare)
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Obesity and renal cell cancer : a quantitative review
- 2001
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Ingår i: British Journal of Cancer. - London, United Kingdom : Nature Publishing Group. - 0007-0920 .- 1532-1827. ; 85:7, s. 984-990
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Forskningsöversikt (refereegranskat)abstract
- Obesity has been associated with an increased risk of renal cell cancer among women, while the evidence for men is considered weaker. We conducted a quantitative summary analysis to evaluate the existing evidence that obesity increases the risk of renal cell cancer both among men and women. We identified all studies examining body weight in relation to kidney cancer, available in MEDLINE from 1966 to 1998. The quantitative summary analysis was limited to studies assessing obesity as body mass index (BMI, kg m(-2)), or equivalent. The risk estimates and the confidence intervals were extracted from the individual studies, and a mixed effect weighted regression model was used. We identified 22 unique studies on each sex, and the quantitative analysis included 14 studies on men and women, respectively. The summary relative risk estimate was 1.07 (95% CI 1.05-1.09) per unit of increase in BMI (corresponding to 3 kg body weight increase for a subject of average height). We found no evidence of effect modification by sex. Our quantitative summary shows that increased BMI is equally strongly associated with an increased risk of renal cell cancer among men and women.
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| 3. |
- Elander, N, et al.
(författare)
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Microwave-enhanced radiochemistry
- 2000
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Ingår i: CHEMICAL SOCIETY REVIEWS. - : Royal Society of Chemistry (RSC). - 0306-0012 .- 1460-4744. ; 29:4, s. 239-249
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Forskningsöversikt (övrigt vetenskapligt/konstnärligt)
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| 4. |
- Fu, Y, et al.
(författare)
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Photocurrents of 14 mu m quantum-well infrared photodetectors
- 2003
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Ingår i: Journal of Applied Physics. - : American Institute of Physics. - 0021-8979 .- 1089-7550. ; 93:12, s. 9432-9436
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Tidskriftsartikel (refereegranskat)abstract
- We study the factors that determine photogenerated carriers and response wavelengths of photocurrents of long wavelength (similar to14 mum) quantum well (QW) infrared photodetectors (QWIPs). The material structures of QWIPs are first characterized by the photoluminescence measurements (PL). By calculating the density of photogenerated carriers in the continuum above the energy barriers using the PL calibrated QWIP structures, we have demonstrated that due to the sample quality, the photocarriers can be either in miniband states (Bloch states in the multiple quantum wells), or they transport from one quantum well to the next in the form of running waves. By including possible scattering processes at the QWIP working temperature to link the theoretically calculated photocarrier density with the experimentally measured photocurrent, it is shown that the width of the photocurrent peaks of 14 mum GaAs/AlGaAs QWIPs under investigation is determined by the optical phonon emissions of photocarriers. We have further calculated the densities of photocarriers in the QWIPs reported in the literature. It is shown that the Bloch wave boundary conditions are appropriate for QWIPs with narrow QWs, whereas running wave boundary conditions are appropriate for wide QWs.
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| 5. |
- Fu, Y, et al.
(författare)
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Quantum mechanical model and simulation of GaAs/AlGaAs quantum well infrared photodetector-I optical aspects
- 2002
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Ingår i: Hongwai yu haomibo xuebao. - : Science Press. - 1001-9014. ; 21:5, s. 321-326
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Tidskriftsartikel (refereegranskat)abstract
- A complete quantum mechanical model for GaAs/AlGaAs quantum well infrared photodetectors(QWIPs) is presented here. The model consisted of four parts: (1) Starting with the description of the electromagnetic field of the infrared radiation in the QWIP, effective component of the vector potential [\A(z)\] along the QWIP growth direction (z-axis) due to the optical diffraction grating was calculated. (2) From the wave transmissions and the occupations of the electronic states, it was discussed that the dark current in the QWIP is determined by the drift-diffusion current of carriers thermally excited from the ground sublevel in the quantum well to extended states above the barrier. (3) The photocurrent was investigated by the optical transition (absorption coefficient between the ground state to excited states due to the nonzero-[\A(z)\]). (4) By studying the inter-diffusion of the At atoms across the GaAs/AlGaAs heterointerfaces, the mobility of the drift-diffusion carriers in the excited states was calculated, so the measurement results of the dark current and photocurrent spectra can be explained theoretically. With the complete quantum mechanical descriptions of (1-4), QWIP device design and optimization are possible.
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| 6. |
- Gómez, M.M., et al.
(författare)
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Dye-sensitized sputtered titanium oxide films for photovoltaic applications : influence of the O2/Ar gas flow ratio during the deposition
- 2003
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Ingår i: Solar Energy Materials and Solar Cells. - 0927-0248 .- 1879-3398. ; 76:1, s. 37-56
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Tidskriftsartikel (refereegranskat)abstract
- Titanium oxide films were prepared by reactive DC magnetron sputtering onto SnO2:F coated glass substrates. The O-2/Ar gas flow ratio was kept at a constant value Gamma during the deposition, and a series of films were deposited with 0.050 < Gamma < 0.072. Structural studies were performed by X-ray diffraction and transmission electron microscopy; the structure displayed penniform features with a clear dependence on F. Charge transport in the films was evaluated by use of time-resolved photocurrents; a diffusion model was fitted to the experimental data and two different transport mechanisms were proposed depending on the film stoichiometry. Dye sensitization in cis-dithiocyanato-bis(2,2'-bipyridyl-4,4'-dicarboxylate) ruthenium (II) was performed to evaluate incident photon-to-current conversion efficiency and solar cell properties of the films. These parameters showed a clear dependence on Gamma. Optical measurements gave evidence for the presence of polaron absorption for the film deposited at Gamma = 0.050.
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| 7. |
- Lockwood, M, et al.
(författare)
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Coordinated Cluster and ground-based instrument observations of transient changes in the magnetopause boundary layer during an interval of predominantly northward IMF : relation to reconnection pulses and FTE signatures
- 2001
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Ingår i: Annales Geophysicae. - : Copernicus GmbH. - 0992-7689 .- 1432-0576. ; 19:10-12, s. 1613-1640
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Forskningsöversikt (refereegranskat)abstract
- We study a series of transient entries into the low-latitude boundary layer (LLBL) of all four Cluster spacecraft during an outbound pass through the mid-afternoon magnetopause ([X(GSM), Y(GSM), Z(GSM)] approximate to [2, 7, 9] R(E)). The events take place during an interval of northward IMF, as seen in the data from the ACE satellite and lagged by a propagation delay of 75 min that is well-defined by two separate studies: (1) the magnetospheric variations prior to the northward turning (Lockwood et al., 2001, this issue) and (2) the field clock angle seen by Cluster after it had emerged into the magnetosheath (Opgenoorth et al., 2001, this issue). With an additional lag of 16.5 min, the transient LLBL events cor-relate well with swings of the IMF clock angle (in GSM) to near 90degrees. Most of this additional lag is explained by ground-based observations, which reveal signatures of transient reconnection in the pre-noon sector that then take 10-15 min to propagate eastward to 15 MLT, where they are observed by Cluster. The eastward phase speed of these signatures agrees very well with the motion deduced by the cross-correlation of the signatures seen on the four Cluster spacecraft. The evidence that these events are reconnection pulses includes: transient erosion of the noon 630 nm (cusp/cleft) aurora to lower latitudes; transient and travelling enhancements of the flow into the polar cap, imaged by the AMIE technique; and poleward-moving events moving into the polar cap, seen by the EISCAT Svalbard Radar (ESR). A pass of the DMSP-F15 satellite reveals that the open field lines near noon have been opened for some time: the more recently opened field lines were found closer to dusk where the flow transient and the poleward-moving event intersected the satellite pass. The events at Cluster have ion and electron characteristics predicted and observed by Lockwood and Hapgood (1998) for a Flux Transfer Event (FTE), with allowance for magnetospheric ion reflection at Alfvenic disturbances in the magnetopause reconnection layer. Like FTEs, the events are about 1 R(E) in their direction of motion and show a rise in the magnetic field strength, but unlike FTEs, in general, they show no pressure excess in their core and hence, no characteristic bipolar signature in the boundary-normal component. However, most of the events were observed when the magnetic field was southward, i.e. on the edge of the interior magnetic cusp, or when the field was parallel to the magnetic equatorial plane. Only when the satellite begins to emerge from the exterior boundary (when the field was northward), do the events start to show a pressure excess in their core and the consequent bipolar signature. We identify the events as the first observations of FTEs at middle altitudes.
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| 8. |
- Lockwood, M., Fazakerley, A., Opgenoorth, H., Moen, J., van Eyken, A.P., Dunlop, M., Bosqued, J.M., Lu, G., Cully, C., Eglitis, P., McCrea, I., Hapgood, M. A., Wild, M.N., Stamper, R., Denig, W., Taylor, M., . Wild, J.A., Provan, G., Amm, O., Kauristie
(författare)
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Coordinated Cluster, ground-based instrumentation and low-altitude satellite observations of transient poleward-moving events in the ionosphere and in the tail lobe
- 2001
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Ingår i: Annales Geophysicae. ; 19:10, s. 1589-1612
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Tidskriftsartikel (refereegranskat)abstract
- During the interval between 8:00–9:30 on 14 January 2001, the four Cluster spacecraft were moving from the central magnetospheric lobe, through the dusk sector mantle, on their way towards intersecting the magnetopause near 15:00 MLT and 15:00 UT. Throug
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| 9. |
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| 10. |
- Neuzil, J., et al.
(författare)
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Induction of cancer cell apoptosis by a-tocopheryl succinate : Molecular pathways and structural requirements
- 2001
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Ingår i: The FASEB Journal. - : Wiley. - 0892-6638 .- 1530-6860. ; 15:2, s. 403-415
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Tidskriftsartikel (refereegranskat)abstract
- The vitamin E analog a-tocopheryl succinate (a-TOS) can induce apoptosis. We show that the proapoptotic activity of a-TOS in hematopoietic and cancer cell lines involves inhibition of protein kinase C (PKC), since phorbol myristyl acetate prevented a-TOS-triggered apoptosis. More selective effectors indicated that a-TOS reduced PKCa isotype activity by increasing protein phosphatase 2A (PP2A) activity. The role of PKCa inhibition in a-TOS-induced apoptosis was confirmed using antisense oligonucleotides or PKCa overexpression. Gain- or loss-of-function bcl-2 mutants implied modulation of bcl-2 activity by PKC/PP2A as a mitochondrial target of a-TOS-induced proapoptotic signals. Structural analogs revealed that a-tocopheryl and succinyl moieties are both required for maximizing these effects. In mice with colon cancer xenografts, a-TOS suppressed tumor growth by 80%. This epitomizes cancer cell killing by a pharmacologically relevant compound without known side effects.
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| 11. |
- Scherer, SW, et al.
(författare)
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Human chromosome 7: DNA sequence and biology
- 2003
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Ingår i: Science (New York, N.Y.). - : American Association for the Advancement of Science (AAAS). - 1095-9203 .- 0036-8075. ; 300:5620, s. 767-772
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Tidskriftsartikel (refereegranskat)abstract
- DNA sequence and annotation of the entire human chromosome 7, encompassing nearly 158 million nucleotides of DNA and 1917 gene structures, are presented. To generate a higher order description, additional structural features such as imprinted genes, fragile sites, and segmental duplications were integrated at the level of the DNA sequence with medical genetic data, including 440 chromosome rearrangement breakpoints associated with disease. This approach enabled the discovery of candidate genes for developmental diseases including autism.
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| 12. |
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