| 1. |
- Villa, Luisa L., et al.
(författare)
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Quadrivalent vaccine against human papillomavirus to prevent high-grade cervical lesions
- 2007
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Ingår i: New England Journal of Medicine. - 0028-4793 .- 1533-4406. ; 356:19, s. 1915-1927
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Human papillomavirus types 16 (HPV-16) and 18 (HPV-18) cause approximately 70% of cervical cancers worldwide. A phase 3 trial was conducted to evaluate a quadrivalent vaccine against HPV types 6, 11, 16, and 18 (HPV-6/11/16/18) for the prevention of high-grade cervical lesions associated with HPV-16 and HPV-18. METHODS: In this randomized, double-blind trial, we assigned 12,167 women between the ages of 15 and 26 years to receive three doses of either HPV-6/11/16/18 vaccine or placebo, administered at day 1, month 2, and month 6. The primary analysis was performed for a per-protocol susceptible population that included 5305 women in the vaccine group and 5260 in the placebo group who had no virologic evidence of infection with HPV-16 or HPV-18 through 1 month after the third dose (month 7). The primary composite end point was cervical intraepithelial neoplasia grade 2 or 3, adenocarcinoma in situ, or cervical cancer related to HPV-16 or HPV-18. RESULTS: Subjects were followed for an average of 3 years after receiving the first dose of vaccine or placebo. Vaccine efficacy for the prevention of the primary composite end point was 98% (95.89% confidence interval [CI], 86 to 100) in the per-protocol susceptible population and 44% (95% CI, 26 to 58) in an intention-to-treat population of all women who had undergone randomization (those with or without previous infection). The estimated vaccine efficacy against all high-grade cervical lesions, regardless of causal HPV type, in this intention-to-treat population was 17% (95% CI, 1 to 31). CONCLUSIONS: In young women who had not been previously infected with HPV-16 or HPV-18, those in the vaccine group had a significantly lower occurrence of high-grade cervical intraepithelial neoplasia related to HPV-16 or HPV-18 than did those in the placebo group.
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| 4. |
- Lundin, Joakim, 1978-, et al.
(författare)
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Analysis of four-wave mixing of high-power lasers for the detection of elastic photon-photon scattering
- 2006
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Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics. - : The American Physical Society. - 1050-2947 .- 1094-1622. ; 74:4, s. 043821-043831
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Tidskriftsartikel (refereegranskat)abstract
- We derive expressions for the coupling coefficients for electromagnetic four-wave mixing in the nonlinear quantum vacuum. An experimental setup for detection of elastic photon-photon scattering is suggested, where three incoming laser pulses collide and generate a fourth wave with a new frequency and direction of propagation. An expression for the number of scattered photons is derived and, using beam parameters for the Astra Gemini system at the Rutherford Appleton Laboratory, it is found that the signal can reach detectable levels. Problems with shot-to-shot reproducibility are reviewed, and the magnitude of the noise arising from competing scattering processes is estimated. It is found that detection of elastic photon-photon scattering may be achieved.
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| 5. |
- Lundström, E., et al.
(författare)
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Using high-power lasers for detection of elastic photon-photon scattering.
- 2006
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Ingår i: Physical Review Letters. - : The American Physical Society. - 0031-9007 .- 1079-7114. ; 96:8, s. 083602-083605
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Tidskriftsartikel (refereegranskat)abstract
- The properties of four-wave interaction via the nonlinear quantum vacuum is investigated. The effect of the quantum vacuum is to generate photons with new frequencies and wave vectors, due to elastic photon-photon scattering. An expression for the number of generated photons is derived, and using state-of-the-art laser data it is found that the number of photons can reach detectable levels. In particular, the prospect of using the high-repetition Astra Gemini system at the Rutherford Appleton Laboratory is discussed. The problem of noise sources is reviewed, and it is found that the noise level can be reduced well below the signal level. Thus, detection of elastic photon-photon scattering may for the first time be achieved.
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| 6. |
- Maire, O., et al.
(författare)
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Effects of food availability on sediment reworking in Abra ovata and A. nitida
- 2006
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Ingår i: Marine Ecology-Progress Series. - 0171-8630. ; 319, s. 135-153
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Tidskriftsartikel (refereegranskat)abstract
- We used a new experimental approach involving thin aquaria, luminophores, time lapse photography and image analysis to assess sediment reworking in 2 closely related bivalves, Abra ovata and A. nitida. The method proved efficient based on the highly significant correlation between the concentrations of luminophores assessed using image analysis and direct counting of sediment slices. A. ovata and A. nitida exhibited different sediment reworking behaviours. A. ovata remained immobile within the sediment and transferred luminophores within the sediment through its siphonal activity, which resulted in the creation of typical inverse conical structures. A. nitida moved within the sediment and reworked a thinner sediment layer. Both A. ovata and A. nitida were characterised as biodiffusers. Biodiffusion coefficients (D-b) were maximal at intermediate food concentration in A. ovata and at high food concentration in A. nitida. This new approach allowed assessment of the effects of spatial scale and vertical grid size on the computation of D-b, In both species D-b decreased with spatial scale up to 3.750 cm and then remained constant. It is suggested that this pattern partly resulted from heterogeneity linked to: (1) the mode of sediment reworking (A. ovata) and (2) the relative proportion of reworked sediment surface (A. nitida). Vertical grid size > 0.250 cm resulted in a significant overestimation of D-b in A. nitida, due to the low thickness of the sediment layer reworked by this species. The implications of these results on the main characteristics (duration, spatial scale, vertical grid size) of classical luminophore experiments are discussed.
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| 7. |
- Trines, R. M. G. M., et al.
(författare)
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Applications of the wave kinetic approach : from laser wakefields to drift wave turbulence
- 2009
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Ingår i: Physics of Plasmas. - : AIP Publishing. - 1070-664X .- 1089-7674. ; 16:5, s. 055904-
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Tidskriftsartikel (refereegranskat)abstract
- Nonlinear wave-driven processes in plasmas are normally described by either a monochromatic pump wave that couples to other monochromatic waves or as a random phase wave coupling to other random phase waves. An alternative approach involves a random or broadband pump coupling to monochromatic and/or coherent structures in the plasma. This approach can be implemented through the wave kinetic model. In this model, the incoming pump wave is described by either a bunch (for coherent waves) or a sea (for random phase waves) of quasiparticles. This approach has been applied to both photon acceleration in laser wakefields and drift wave turbulence in magnetized plasma edge configurations. Numerical simulations have been compared to experiments, varying from photon acceleration to drift mode-zonal flow turbulence, and good qualitative correspondences have been found in all cases.
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| 8. |
- Trines, R. M. G. M., et al.
(författare)
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Simulation of zonal flow excitation by drift mode turbulence : applications to tokamaks and the magnetopause
- 2008
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Ingår i: Plasma Physics and Controlled Fusion. - : IOP Publishing. - 0741-3335 .- 1361-6587. ; 50:12, s. 124048-
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Tidskriftsartikel (refereegranskat)abstract
- Recently, we investigated the interaction between broadband drift mode turbulence and zonal flows near the edge of a region of magnetized plasma (Trines et al 2005 Phys. Rev. Lett. 94 165002). Our simulation results showed the development of a zonal flow through the modulational instability of the drift wave distribution, as well as the existence of solitary zonal flow structures about an ion gyroradius wide, drifting towards steeper relative density gradients. Both the growth rate of the turbulence and the particle/energy transport across the plasma boundary can be stabilized by adjusting the plasma density gradient. This spontaneous formation of solitary wave structures has also been found in Cluster satellite observations (Trines et al 2007 Phys. Rev. Lett. 99 205006), confirming our earlier theoretical predictions. We will discuss the consequences of our results for our understanding of the Earth's magnetopause, as well as for the study of zonal flows in tokamaks.
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| 9. |
- Trines, R., et al.
(författare)
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Spontaneous generation of self-organized solitary wave structures at earth's magnetopause
- 2007
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 99:20, s. 205006-
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Tidskriftsartikel (refereegranskat)abstract
- Spontaneous formation of solitary wave structures has been observed in Earth's magnetopause, and is shown to be caused by the breakup of a zonal flow by the action of drift wave turbulence. Here we show matched observations and modeling of coherent, large-scale solitary electrostatic structures, generated during the interaction of short-scale drift wave turbulence and zonal flows at the Earth's magnetopause. The observations were made by the Cluster spacecraft and the numerical modeling was performed using the wave-kinetic approach to drift wave-zonal flow interactions. Good agreement between observations and simulations has been found, thus explaining the emergence of the observed solitary structures as well as confirming earlier theoretical predictions of their existence.
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| 12. |
- Mendonca, J T, et al.
(författare)
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A kinetic approach to Bose-Einstein condensates : self-phase modulation and Bogoliubov oscillations
- 2005
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Ingår i: Journal of Experimental and Theoretical Physics. - New York : Maik Nauka/Interperiodica. - 1063-7761 .- 1090-6509. ; 101:5, s. 942-948
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Tidskriftsartikel (refereegranskat)abstract
- A kinetic approach to Bose-Einstein condensates (BECs) is proposed based on the Wigner-Moyal equation (WME). In the semiclassical limit, the WME reduces to the particle-number conservation equation. Two examples of applications are (i) a self-phase modulation of a BE condensate beam, where we show that part of the beam is decelerated and eventually stops as a result of the gradient of the effective self-potential, and (ii) the derivation of a kinetic dispersion relation for sound waves in BECs, including collisionless Landau damping.
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| 13. |
- Mendonca, J. T., et al.
(författare)
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Neutrino orbital angular momentum in a plasma vortex
- 2008
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Ingår i: Europhysics letters. - : IOP Publishing. - 0295-5075 .- 1286-4854. ; 84:4, s. 41001-
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Tidskriftsartikel (refereegranskat)abstract
- It is shown that an electron-neutrino beam, propagating in a background plasma, can be decomposed into orbital momentum (OAM) states, similar to the OAM photon states. Coupling between different OAM neutrino states, in the presence of a plasma vortex, is considered. We show that plasma vorticity can be transfered to the neutrino beam, which is relevant to the understanding of the neutrino sources in astrophysics. Observation of neutrino OAM states could eventually become possible.
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| 14. |
- Mendonça, J.T., et al.
(författare)
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Photon acceleration in vacuum
- 2006
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Ingår i: Physics Letters A. ; 359, s. 700-704
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Tidskriftsartikel (refereegranskat)
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| 15. |
- Mendonca, J. T., et al.
(författare)
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Plasmons with orbital angular momentum
- 2009
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Ingår i: Physics of Plasmas. - : AIP Publishing. - 1070-664X .- 1089-7674. ; 16:11, s. 112103-
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Tidskriftsartikel (refereegranskat)abstract
- Electron plasma waves carrying orbital angular momentum are investigated in an unmagnetized collisionless plasma composed of inertial electrons and static ions. For this purpose, the usual plasmon dispersion relation is employed to derive an approximate paraxial equation. The latter is analyzed with a Gaussian beam solution. For a finite angular momentum associated with the plasmon, Laguerre-Gaussian (LG) solutions are employed for solving the electrostatic potential problem which gives approximate solution and is valid for plasmon beams in the paraxial approximation. The LG potential determines the electric field components and energy flux of plasmons with finite angular momentum. Numerical illustrations show that the radial and angular mode numbers strongly modify the profiles of the LG potential.
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| 16. |
- Mendonca, J. T., et al.
(författare)
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Stimulated Raman and Brillouin Backscattering of Collimated Beams Carrying Orbital Angular Momentum
- 2009
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 102:18, s. 185005-
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Tidskriftsartikel (refereegranskat)abstract
- We study theoretically the exchange of angular momentum between electromagnetic and electrostatic waves in a plasma, due to the stimulated Raman and Brillouin backscattering processes. Angular momentum states for plasmon and phonon fields are introduced for the first time. We demonstrate that these states can be excited by nonlinear wave mixing, associated with the scattering processes. This could be relevant for plasma diagnostics, both in laboratory and in space. Nonlinearly coupled paraxial equations and instability growth rates are derived.
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| 17. |
- Palm, Fredrik, et al.
(författare)
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Angiotensin II Type 2 Receptors and Nitric Oxide Sustain Oxygenation in the Clipped Kidney of Early Goldblatt Hypertensive Rats
- 2008
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Ingår i: Hypertension. - 0194-911X .- 1524-4563. ; 51:2, s. 345-351
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Tidskriftsartikel (refereegranskat)abstract
- Angiotensin-converting enzyme inhibitors (ACEIs) decrease the glomerular filtration rate and renal blood flow in the clipped kidneys of early 2-kidney, 1-clip Goldblatt hypertensive rats, but the consequences for oxygenation are unclear. We investigated the hypothesis that angiotensin II type 1 or angiotensin II type 2 receptors or NO synthase mediate renal oxygenation responses to ACEI. Three weeks after left renal artery clipping, kidney function, oxygen (O2) use, renal blood flow, renal cortical blood flow, and renal cortical oxygen tension (PO2) were measured after acute administration of an ACEI (enalaprilat) and after acute administration of ACEI following acute administration of an angiotensin II type 1 or angiotensin II type 2 receptor blocker (candesartan or PD-123,319) or an NO synthase blocker (NG-nitro-L-arginine methyl ester with control of renal perfusion pressure) and compared with mechanical reduction in renal perfusion pressure to the levels after ACEI. The basal renal cortical PO2 of clipped kidneys was significantly lower than contralateral kidneys (35±1 versus 51±1 mm Hg; n=40 each). ACEI lowered renal venous PO2, cortical PO2, renal blood flow, glomerular filtration rate, and cortical blood flow and increased the renal vascular resistance in the clipped kidney, whereas mechanical reduction in renal perfusion pressure was ineffective. PD-123,319 and NG-nitro-L-arginine methyl ester, but not candesartan, reduced the PO2 of clipped kidneys and blocked the fall in PO2 with acute ACEI administration. In conclusion, oxygen availability in the clipped kidney is maintained by angiotensin II generation, angiotensin II type 2 receptors, and NO synthase. This discloses a novel mechanism whereby angiotensin can prevent hypoxia in a kidney challenged with a reduced perfusion pressure.
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