| 1. |
- Cavalieri, A L, et al.
(författare)
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Clocking femtosecond X rays.
- 2005
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Ingår i: Phys Rev Lett. - 0031-9007. ; 94:11
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Tidskriftsartikel (refereegranskat)abstract
- Linear-accelerator-based sources will revolutionize ultrafast x-ray science due to their unprecedented brightness and short pulse duration. However, time-resolved studies at the resolution of the x-ray pulse duration are hampered by the inability to precisely synchronize an external laser to the accelerator. At the Sub-Picosecond Pulse Source at the Stanford Linear-Accelerator Center we solved this problem by measuring the arrival time of each high energy electron bunch with electro-optic sampling. This measurement indirectly determined the arrival time of each x-ray pulse relative to an external pump laser pulse with a time resolution of better than 60 fs rms.
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| 2. |
- Gaffney, K J, et al.
(författare)
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Observation of structural anisotropy and the onset of liquidlike motion during the nonthermal melting of InSb
- 2005
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Ingår i: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 95:12
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Tidskriftsartikel (refereegranskat)abstract
- The melting dynamics of laser excited InSb have been studied with femtosecond x-ray diffraction. These measurements observe the delayed onset of diffusive atomic motion, signaling the appearance of liquidlike dynamics. They also demonstrate that the root-mean-squared displacement in the [111] direction increases faster than in the [110] direction after the first 500 fs. This structural anisotropy indicates that the initially generated fluid differs significantly from the equilibrium liquid.
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| 3. |
- Szatmari, Peter, et al.
(författare)
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Mapping autism risk loci using genetic linkage and chromosomal rearrangements.
- 2007
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 39:3, s. 319-328
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Tidskriftsartikel (refereegranskat)abstract
- Autism spectrum disorders (ASDs) are common, heritable neurodevelopmental conditions. The genetic architecture of ASDs is complex, requiring large samples to overcome heterogeneity. Here we broaden coverage and sample size relative to other studies of ASDs by using Affymetrix 10K SNP arrays and 1,168 families with at least two affected individuals, performing the largest linkage scan to date while also analyzing copy number variation in these families. Linkage and copy number variation analyses implicate chromosome 11p12-p13 and neurexins, respectively, among other candidate loci. Neurexins team with previously implicated neuroligins for glutamatergic synaptogenesis, highlighting glutamate-related genes as promising candidates for contributing to ASDs.
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| 4. |
- Clark, Andrew G., et al.
(författare)
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Evolution of genes and genomes on the Drosophila phylogeny
- 2007
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 450:7167, s. 203-218
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Tidskriftsartikel (refereegranskat)abstract
- Comparative analysis of multiple genomes in a phylogenetic framework dramatically improves the precision and sensitivity of evolutionary inference, producing more robust results than single-genome analyses can provide. The genomes of 12 Drosophila species, ten of which are presented here for the first time (sechellia, simulans, yakuba, erecta, ananassae, persimilis, willistoni, mojavensis, virilis and grimshawi), illustrate how rates and patterns of sequence divergence across taxa can illuminate evolutionary processes on a genomic scale. These genome sequences augment the formidable genetic tools that have made Drosophila melanogaster a pre-eminent model for animal genetics, and will further catalyse fundamental research on mechanisms of development, cell biology, genetics, disease, neurobiology, behaviour, physiology and evolution. Despite remarkable similarities among these Drosophila species, we identified many putatively non-neutral changes in protein-coding genes, non-coding RNA genes, and cis-regulatory regions. These may prove to underlie differences in the ecology and behaviour of these diverse species.
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| 5. |
- Fritz, D. M., et al.
(författare)
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Ultrafast bond softening in bismuth : Mapping a solid's interatomic potential with X-rays
- 2007
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 315:5812, s. 633-636
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Tidskriftsartikel (refereegranskat)abstract
- Intense femtosecond laser excitation can produce transient states of matter that would otherwise be inaccessible to laboratory investigation. At high excitation densities, the interatomic forces that bind solids and determine many of their properties can be substantially altered. Here, we present the detailed mapping of the carrier density-dependent interatomic potential of bismuth approaching a solid-solid phase transition. Our experiments combine stroboscopic techniques that use a high-brightness linear electron accelerator-based x-ray source with pulse-by-pulse timing reconstruction for femtosecond resolution, allowing quantitative characterization of the interatomic potential energy surface of the highly excited solid.
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| 6. |
- Elsik, Christine G., et al.
(författare)
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The Genome Sequence of Taurine Cattle : A Window to Ruminant Biology and Evolution
- 2009
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 324:5926, s. 522-528
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Tidskriftsartikel (refereegranskat)abstract
- To understand the biology and evolution of ruminants, the cattle genome was sequenced to about sevenfold coverage. The cattle genome contains a minimum of 22,000 genes, with a core set of 14,345 orthologs shared among seven mammalian species of which 1217 are absent or undetected in noneutherian (marsupial or monotreme) genomes. Cattle-specific evolutionary breakpoint regions in chromosomes have a higher density of segmental duplications, enrichment of repetitive elements, and species-specific variations in genes associated with lactation and immune responsiveness. Genes involved in metabolism are generally highly conserved, although five metabolic genes are deleted or extensively diverged from their human orthologs. The cattle genome sequence thus provides a resource for understanding mammalian evolution and accelerating livestock genetic improvement for milk and meat production.
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| 7. |
- Hillyard, P. B., et al.
(författare)
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Carrier-density-dependent lattice stability in InSb
- 2007
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 98:12, s. 125501-
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Tidskriftsartikel (refereegranskat)abstract
- The ultrafast decay of the x-ray diffraction intensity following laser excitation of an InSb crystal has been utilized to observe carrier dependent changes in the potential energy surface. For the first time, an abrupt carrier dependent onset for potential energy surface softening and the appearance of accelerated atomic disordering for a very high average carrier density have been observed. Inertial dynamics dominate the early stages of crystal disordering for a wide range of carrier densities between the onset of crystal softening and the appearance of accelerated atomic disordering.
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| 8. |
- Lindenberg, A. M., et al.
(författare)
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X-ray diffuse scattering measurements of nucleation dynamics at femtosecond resolution.
- 2008
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 100:13, s. 135502-1-135502-5
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Tidskriftsartikel (refereegranskat)abstract
- Femtosecond time-resolved small and wide angle x-ray diffuse scattering techniques are applied to investigate the ultrafast nucleation processes that occur during the ablation process in semiconducting materials. Following intense optical excitation, a transient liquid state of high compressibility characterized by large-amplitude density fluctuations is observed and the buildup of these fluctuations is measured in real time. Small-angle scattering measurements reveal snapshots of the spontaneous nucleation of nanoscale voids within a metastable liquid and support theoretical predictions of the ablation process.
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| 9. |
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| 10. |
- Lindenberg, AM, et al.
(författare)
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Atomic-scale visualization of inertial dynamics
- 2005
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 1095-9203 .- 0036-8075. ; 308:5720, s. 392-395
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Tidskriftsartikel (refereegranskat)abstract
- The motion of atoms on interatomic potential energy surfaces is fundamental to the dynamics of liquids and solids. An accelerator-based source of femtosecond x-ray pulses allowed us to follow directly atomic displacements on an optically modified energy landscape, leading eventually to the transition from crystalline solid to disordered liquid. We show that, to first order in time, the dynamics are inertial, and we place constraints on the shape and curvature of the transition-state potential energy surface. Our measurements point toward analogies between this nonequilibrium phase transition and the short-time dynamics intrinsic to equilibrium liquids.
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| 11. |
- Roobol, Monique J., et al.
(författare)
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Prostate Cancer Mortality Reduction by Prostate-Specific Antigen-Based Screening Adjusted for Nonattendance and Contamination in the European Randomised Study of Screening for Prostate Cancer (ERSPC)
- 2009
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Ingår i: European Urology. - : Elsevier BV. - 1873-7560 .- 0302-2838. ; 56:4, s. 584-591
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Tidskriftsartikel (refereegranskat)abstract
- Background: Prostate-specific antigen (PSA) based screening for prostate cancer (PCa) has been shown to reduce prostate specific mortality by 20% in an intention to screen (ITS) analysis in a randomised trial (European Randomised Study of Screening for Prostate Cancer [ERSPC]). This effect may be diluted by nonattendance in men randomised to the screening arm and contamination in men randomised to the control arm. Objective: To assess the magnitude of the PCa-specific mortality reduction after adjustment for nonattendance and contamination. Design, setting, and participants: We analysed the occurrence of PCa deaths during an average follow-up of 9 yr in 162 243 men 55-69 yr of age randomised in seven participating centres of the ERSPC. Centres were also grouped according to the type of randomisation (ie, before or after informed written consent). Intervention: Nonattendance was defined as nonattending the initial screening round in ERSPC. The estimate of contamination was based on PSA use in controls in ERSPC Rotterdam. Measurements: Relative risks (RRs) with 95% confidence intervals (Cis) were compared between an ITS analysis and analyses adjusting for nonattendance and contamination using a statistical method developed for this purpose. Results and limitations: In the ITS analysis, the RR of PCa death in men allocated to the intervention arm relative to the control arm was 0.80 (95% CI, 0.68-0.96). Adjustment for nonattendance resulted in a RR of 0.73 (95% CI, 0.58-0.93), and additional adjustment for contamination using two different estimates led to estimated reductions of 0.69 (95% CI, 0.51-0.92) to 0.71 (95% CI, 0.55-0.93), respectively. Contamination data were obtained through extrapolation of single-centre data. No heterogeneity was found between the groups of centres. Conclusions: PSA screening reduces the risk of dying of PCa by up to 31% in men actually screened. This benefit should be weighed against a degree of over diagnosis and overtreatment inherent in PCa screening. (C) 2009 European Association of Urology. Published by Elsevier B.V. All rights reserved.
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| 12. |
- Schroeder, Fritz H., et al.
(författare)
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Can dutasteride delay or prevent the progression of prostate cancer in patients with biochemical failure after radical therapy? Rationale and design of the Avodart after Radical Therapy for Prostate Cancer Study
- 2009
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Ingår i: BJU International. - 1464-4096. ; 103:5, s. 590-596
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Tidskriftsartikel (refereegranskat)abstract
- To describe the Avodart after Radical Therapy for prostate cancer Study (ARTS), investigating the use of dutasteride (a dual 5 alpha-reductase inhibitor that suppresses intraprostatic dihydrotestosterone, reduces tumour volume and improves other markers of tumour regression in prostate cancer) to prevent or delay disease progression in patients with biochemical recurrence after therapy with curative intent. An increasing serum prostate-specific antigen (PSA) level after radical prostatectomy (RP) or radiotherapy (RT) is indicative of recurrent prostate cancer and typically pre-dates clinically detectable metastatic disease by several years. ARTS is an ongoing European multicentre trial in which patients are stratified by previous therapy (RP with or without salvage RT vs primary RT) and randomized to double-blind treatment with dutasteride 0.5 mg or placebo once daily for 2 years. Eligible patients will have a PSA doubling time (DT) of 3-24 months. Biochemical recurrence is defined as three increases in PSA level from the nadir, with each increase >= 4 weeks apart and each PSA level >= 0.2 ng/mL, and a final PSA level of >= 0.4 ng/mL (after RP) or >= 2 ng/mL (after primary RT). Study endpoints include time to PSA doubling, time to disease progression, treatment response (PSA decrease or an increase of <= 15% from baseline), changes in PSA and PSADT, and changes in anxiety (Memorial Anxiety Scale for Prostate Cancer). ARTS will be the first study to evaluate the effects of dutasteride on PSADT, disease progression and treatment response in patients with biochemical failure after RP or RT, and should help to elucidate the potential role of dual 5 alpha-reductase inhibition in prostate cancer.
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| 13. |
- Schröder, Fritz H, et al.
(författare)
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Screening and prostate-cancer mortality in a randomized European study.
- 2009
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Ingår i: The New England journal of medicine. - 1533-4406 .- 0028-4793. ; 360:13, s. 1320-8
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The European Randomized Study of Screening for Prostate Cancer was initiated in the early 1990s to evaluate the effect of screening with prostate-specific-antigen (PSA) testing on death rates from prostate cancer.
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| 14. |
- van den Bergh, Roderick C N, et al.
(författare)
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Gleason score 7 screen-detected prostate cancers initially managed expectantly: outcomes in 50 men.
- 2009
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Ingår i: BJU international. - 1464-410X. ; 103:11, s. 1472-7
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE To assess whether men newly diagnosed with Gleason 7 prostate cancer are eligible for active surveillance (AS) instead of radical treatment. AS is an appropriate initial strategy in selected men who are presently diagnosed with prostate cancer, as many tumours will not progress during a patient's lifetime. PATIENTS AND METHODS Cancer-specific-, overall and treatment-free survival were analysed retrospectively in men with Gleason score 7 cancer who were initially managed expectantly. All were screen-detected in four centres of the European Randomized Study of Screening for Prostate Cancer. RESULTS In 50 men active therapy was initially withheld if they had Gleason 7 disease; 29 of 50 (58%) would otherwise have been suitable for AS, as they had a prostate-specific antigen (PSA) level of < or =10.0 ng/mL, a PSA density of <0.2 ng/mL/mL, stage T1c/T2, and two or fewer positive biopsy-cores; 44 of 50 (88%) had a Gleason score 3 + 4 = 7. The mean (range) age of the men was 69.5 (59.6-76.2) years and the median (interquartile range) follow-up was 2.6 (0.8-5.0) years; the mean American Society of Anesthesiologists score was 1.8. The 6-year cancer-specific survival (nine patients at risk) was 100%, which sharply contrasted with the 68% overall survival. Men alive at the time of analysis had a favourable PSA level and PSA-doubling time. The 6-year treatment-free survival was only 59%, with most patients switching to active therapy, justified on the basis of their PSA level. However, men with otherwise favourable tumour characteristics and a Gleason score of 3 + 4 = 7 remained treatment-free significantly longer than their counterparts with unfavourable other tumour features and a Gleason score of 4 + 3 = 7. CONCLUSION In selected patients with screen-detected Gleason 3 + 4 = 7 prostate cancer, AS might be an option, especially in those with comorbidity and/or a short life-expectancy.
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| 15. |
- Arzel, Celiné, et al.
(författare)
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Experimental functional response and inter-individual variation in foraging rate of teal (Anas crecca)
- 2007
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Ingår i: Behavioural Processes. - 0376-6357 .- 1872-8308. - 0376-6357 ; 75:1, s. 66-71
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Tidskriftsartikel (refereegranskat)abstract
- The functional response, i.e. the change in per capita food intake rate per time unit with changed food availability, is a widely used too] for understanding the ecology and behaviour of animals. However, waterfowl remain poorly explored in this context. In an aviary experiment we derived a functional response curve for teal (Anas crecca) foraging on rice (Oryza sativa) seeds. We found a linear relationship between intake rate and seed density, as expected for a filter-feeder. At high seed densities we found a threshold, above which intake rate still increased linearly but with a lower slope, possibly reflecting a switch from filter-feeding to a scooping foraging mode. The present study shows that food intake rate in teal is linearly related to food availability within the range of naturally occurring seed densities, a finding with major implications for management and conservation of wetland habitats.
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| 16. |
- Arzel, Celiné, et al.
(författare)
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Experimental functional response and inter-individual variation in foraging rate of teal (Anas crecca)
- 2007
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Ingår i: Behavioural Processes. - : Elsevier. - 0376-6357 .- 1872-8308. ; 75:1, s. 66-71
-
Tidskriftsartikel (refereegranskat)abstract
- The functional response, i.e. the change in per capita food intake rate per time unit with changed food availability, is a widely used too] for understanding the ecology and behaviour of animals. However, waterfowl remain poorly explored in this context. In an aviary experiment we derived a functional response curve for teal (Anas crecca) foraging on rice (Oryza sativa) seeds. We found a linear relationship between intake rate and seed density, as expected for a filter-feeder. At high seed densities we found a threshold, above which intake rate still increased linearly but with a lower slope, possibly reflecting a switch from filter-feeding to a scooping foraging mode. The present study shows that food intake rate in teal is linearly related to food availability within the range of naturally occurring seed densities, a finding with major implications for management and conservation of wetland habitats.
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| 17. |
- Bark, Fritz H., et al.
(författare)
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A note on electrolysis with forced convection at large peclet number in a channel and an excess of supporting electrolyte
- 2008
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Ingår i: Russian journal of electrochemistry. - : Pleiades Publishing Ltd. - 1023-1935 .- 1608-3342. ; 44:4, s. 470-478
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Tidskriftsartikel (refereegranskat)abstract
- Electrolysis of an aqueous solution of a metal salt with an excess of supporting electrolyte flowing in a two-dimensional channel is considered. The reaction kinetics is modeled by a Butler - Volmer law. The metal electrodes are symmetrically flush mounted in the channel walls, which are otherwise electrically insulating. Using the perturbation scheme originally proposed by Levich for electrolytes with an excess of supporting electrolyte, a solution in closed form, involving the root of a transcendental algebraic equation, is obtained for the polarization curve. For small and large values of the potential difference between the electrodes, explicit expressions for the polarization curve and the distributions of electric current and concentration on the electrodes are obtained. Particular attention is given to the conditions prevailing during the asymptotic approach to the limiting current.
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| 18. |
- Bastian, Patrick J., et al.
(författare)
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Insignificant Prostate Cancer and Active Surveillance: From Definition to Clinical Implications
- 2009
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Ingår i: European Urology. - : Elsevier BV. - 1873-7560 .- 0302-2838. ; 55:6, s. 1321-1332
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Forskningsöversikt (refereegranskat)abstract
- Context: Due to early detection strategies, prostate cancer is diagnosed early in its natural history. It remains unclear whether all patients diagnosed with prostate cancer warrant radical treatment or may benefit from delayed intervention following active surveillance. Objective: A systematic review of active surveillance protocols to investigate the inclusion criteria for active surveillance and the outcome of treatment. Evidence acquisition: Medline was searched using the following terms: prostate cancer, active surveillance and expectant management for dates up to October 2008. Further studies were chosen on the basis of manual searches of reference lists and review papers. Evidence synthesis: Numerous studies on active surveillance were identified. The recent inclusion criteria of the studies are rather similar. Keeping the short follow-up of all studies in mind, the majority of men stay on active surveillance, and the percentage of patients receiving active treatment is as high as 35% of all patients. Once a patients requires active treatment, most patients still present with curable prostate cancer. Furthermore, only few deaths due to prostate cancer have occurred. Conclusions: Active surveillance is an alternative option to immediate treatment of men with presumed insignificant prostate cancer. It seems that criteria used to identify men with low-risk prostate cancer are rather similar, and immediate treatment of men meeting these criteria may result in an unnecessary number of treatments in these highly selected patients. Data from randomised trials comparing active surveillance and active treatment will provide additional insight into outcome and follow-up strategies. (C) 2009 Published by Elsevier B.V. on behalf of European Association of Urology.
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| 19. |
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| 20. |
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| 21. |
- Borg, K. I., et al.
(författare)
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Effects of non-linear kinetics on free convection in an electrochemical cell with a porous separator
- 2007
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Ingår i: Journal of Applied Electrochemistry. - : Springer Science and Business Media LLC. - 0021-891X .- 1572-8838. ; 37:11, s. 1287-1302
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Tidskriftsartikel (refereegranskat)abstract
- The spatial evolution of the ionic concentration of an electrolyte in an isothermal electrochemical cell with a porous separator between the electrodes was investigated for large values of Rayleigh number. The reaction kinetics were described by the Butler-Volmer equation. The full problem, involving the coupled partial differential equations describing the velocity field, the ionic concentration, and the electric potential, was reduced by means of regular and singular perturbation theory, to a simplified evolution equation, coupled with a transcendental function for the ionic concentration and electric potential; the solution was found to agree well with the numerical solution of the full problem. In the limit of large and small cell voltages, closed analytical solutions were secured for the concentration, potential, and overall current density.
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| 22. |
- Chi, Kim N., et al.
(författare)
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Castration-resistant Prostate Cancer: From New Pathophysiology to New Treatment Targets
- 2009
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Ingår i: European Urology. - : Elsevier BV. - 1873-7560 .- 0302-2838. ; 56:4, s. 594-605
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Tidskriftsartikel (refereegranskat)abstract
- Context: Castration-resistant prostate cancer (CRPC) refers to patients who no longer respond to surgical or medical castration. Standard treatment options are limited. Objective: To review the concepts and rationale behind targeted agents currently in late-stage clinical testing for patients with CRPC. Evidence acquisition: Novel targeted therapies in clinical trials were identified from registries. The MEDLINE database was searched for all relevant reports published from 1996 to October 2009. Bibliographies of the retrieved articles and major international meeting abstracts were hand-searched to identify additional studies. Evidence synthesis: Advances in our understanding of the molecular mechanisms underlying prostate cancer (PCa) progression has translated into a variety of treatment approaches. Agents targeting androgen receptor (AR) activation and local steroidogenesis, angiogenesis, immunotherapy, apoptosis, chaperone proteins, the insulin-like growth factor (IGF) pathway, RANK-ligand, endothelin receptors, and the Src family kinases are entering or have recently completed accrual to phase 3 trials for patients with CRPC. Conclusions: A number of new agents targeting mechanisms of PCa progression with early promising results are in clinical trials and have the potential to provide novel treatment options for CRPC in the near future. (C) 2009 European Association of Urology. Published by Elsevier B.V. All rights reserved.
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| 23. |
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| 24. |
- Grenabo Bergdahl, Anna, et al.
(författare)
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Interval cancers in prostate cancer screening: comparing 2- and 4-year screening intervals in the European Randomized Study of Screening for Prostate Cancer, Gothenburg and Rotterdam.
- 2007
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Ingår i: Journal of the National Cancer Institute. - : Oxford University Press (OUP). - 1460-2105 .- 0027-8874. ; 99:17, s. 1296-303
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Tidskriftsartikel (refereegranskat)abstract
- The incidence of prostate cancer has increased substantially since it became common practice to screen asymptomatic men for the disease. The European Randomized Study of Screening for Prostate Cancer (ERSPC) was initiated in 1993 to determine how prostate-specific antigen (PSA) screening affects prostate cancer mortality. Variations in the screening algorithm, such as the interval between screening rounds, likely influence the morbidity, mortality, and quality of life of the screened population.We compared the number and characteristics of interval cancers, defined as those diagnosed during the screening interval but not detected by screening, in men in the screening arm of the ERSPC who were aged 55-65 years at the time of the first screening and were participating through two centers of the ERSPC: Gothenburg (2-year screening interval, n = 4202) and Rotterdam (4-year screening interval, n = 13301). All participants who were diagnosed with prostate cancer through December 31, 2005, but at most 10 years after the initial screening were ascertained by linkage with the national cancer registries. A potentially life-threatening (aggressive) interval cancer was defined as one with at least one of the following characteristics at diagnosis: stage M1 or N1, plasma PSA concentration greater than 20.0 ng/mL, or Gleason score greater than 7. We used Mantel Cox regression to assess differences between rates of interval cancers and aggressive interval cancers at the two centers. All statistical tests were two-sided.The 10-year cumulative incidence of all prostate cancers in Rotterdam versus Gothenburg was 1118 (8.41%) versus 552 (13.14%) (P<.001), the cumulative incidence of interval cancer was 57 (0.43%) versus 31 (0.74%) (P = .51), and the cumulative incidence of aggressive interval cancer was 15 (0.11%) versus 5 (0.12%) (P = .72).The rate of interval cancer, especially aggressive interval cancer, was low in this study. The 2-year screening interval had higher detection rates than the 4-year interval but did not lead to lower rates of interval and aggressive interval prostate cancers.
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| 25. |
- Ipek, Nulifer, et al.
(författare)
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Numerical and experimental study of the effect of gas evolution in electrolytic pickling
- 2006
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Ingår i: Journal of Applied Electrochemistry. - : Springer Science and Business Media LLC. - 0021-891X .- 1572-8838. ; 36:12, s. 1367-1379
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Tidskriftsartikel (refereegranskat)abstract
- As part of a progressive approach to model the electrolytic pickling process, this paper focuses on the important aspect of hydrogen and oxygen gas evolution on the electrodes and on the steel strip being pickled. The system considered consists of type 316 stainless steel pickled in aqueous sodium sulphate, with lead anodes and stainless steel cathodes. The mathematical model is two-dimensional steady-state, and includes the differential equations describing the effect of migration, giving the potential and current fields, and the Tafel kinetic rate expressions for hydrogen and oxygen gas generation. Experiments were conducted to obtain a better understanding of the process and for model validation. Good agreement between the experimental measurements of the global current efficiency and the model predictions was obtained.
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| 26. |
- Paetzold, Martin, et al.
(författare)
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Rosetta Radio Science Investigations (RSI)
- 2007
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Ingår i: Space Science Reviews. - : Springer Science and Business Media LLC. - 0038-6308 .- 1572-9672. ; 128:1-4, s. 599-627
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Forskningsöversikt (refereegranskat)abstract
- The Rosetta spacecraft has been successfully launched on 2nd March 2004 to its new target comet 67 P/Churyurnov-Gerasimenko. The science objectives of the Rosetta Radio Science Investigations (RSI) experiment address fundamental aspects of cometary physics such as the mass and bulk density of the nucleus, its gravity field, its interplanetary orbit perturbed by nongravitational forces, its size and shape, its internal structure, the composition and roughness of the nucleus surface, the abundance of large dust grains, the plasma content in the coma and the combined dust and gas mass flux. The masses of two asteroids, Steins and Lutetia, shall be determined during flybys in 2008 and 2010. respectively. Secondary objectives are the radio sounding of the solar corona during the superior conjunctions of the spacecraft with the Sun during the cruise phase. The radio carrier links of the spacecraft Telemetry, Tracking and Command (TT&C) subsystem between the orbiter and the Earth will be used for these investigations. An Ultrastable oscillator (USO) connected to both transponders of the radio subsystem serves as a stable frequency reference source for both radio downlinks at X-band (8.4 GHz) and S-band (2.3 GHz) in the one-way mode. The Simultaneous and coherent dual-frequency downlinks via the High Gain Antenna (HGA) permit separation of contributions from the classical Doppler shift and the dispersive media effects caused by the motion of the spacecraft with respect to the Earth and the propagation of the signals through the dispersive media, respectively.
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| 27. |
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| 28. |
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| 29. |
- Vickers, Andrew J., et al.
(författare)
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Prostate-Specific Antigen Velocity for Early Detection of Prostate Cancer: Result from a Large, Representative, Population-based Cohort
- 2009
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Ingår i: European Urology. - : Elsevier BV. - 1873-7560 .- 0302-2838. ; 56:5, s. 753-760
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Tidskriftsartikel (refereegranskat)abstract
- Background: It has been suggested that changes in prostate-specific antigen (PSA) over time (ie, PSA velocity [PSAV]) aid prostate cancer detection. Some guidelines do incorporate PSAV cut points as an indication for biopsy. Objective: To evaluate whether PSAV enhances prediction of biopsy outcome in a large, representative, population-based cohort. Design, setting, and participants: There were 2742 screening-arm participants with PSA < 3 ng/ml at initial screening in the European Randomized Study of Screening for Prostate Cancer in Rotterdam, Netherlands, or Goteborg, Sweden, and who were subsequently biopsied during rounds 2-6 due to elevated PSA. Measurements: Total, free, and intact PSA and human kallikrein 2 were measured for 16 screening rounds at intervals of 2 or 4 yr. We created logistic regression models to predict prostate cancer based on age and PSA, with or without free-to-total PSA ratio (%fPSA). PSAV was added to each model and any enhancement in predictive accuracy assessed by area under the curve (AUC). Results and limitations: PSAV led to small enhancements in predictive accuracy (AUC of 0.569 vs 0.531; 0.626 vs 0.609 if %fPSA was included), although not for high-grade disease. The enhancement depended on modeling a nonlinear relationship between PSAV and cancer. There was no benefit if we excluded men with higher velocities, which were associated with lower risk. These results apply to men in a screening program with elevated PSA; men with prior negative biopsy were not evaluated in this study. Conclusions: In men with PSA of about >= 3 ng/ml, we found little justification for formal calculation of PSAV or for use of PSAV cut points to determine biopsy. Informal assessment of PSAV will likely aid clinical judgment, such as a sudden rise in PSA suggesting prostatitis, which could be further evaluated before biopsy. (C) 2009 European Association of Urology. Published by Elsevier B. V. All rights reserved.
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