| 1. |
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- 2017
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Ingår i: Physical Review D. - 2470-0010 .- 2470-0029. ; 96:2
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Tidskriftsartikel (refereegranskat)
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| 2. |
- Adrian-Martinez, S., et al.
(författare)
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A first search for coincident gravitational waves and high energy neutrinos using LIGO, Virgo and ANTARES data from 2007
- 2013
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Ingår i: Journal of Cosmology and Astroparticle Physics. - : IOP Publishing. - 1475-7516. ; :6
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Tidskriftsartikel (refereegranskat)abstract
- We present the results of the first search for gravitational wave bursts associated with high energy neutrinos. Together, these messengers could reveal new, hidden sources that are not observed by conventional photon astronomy, particularly at high energy. Our search uses neutrinos detected by the underwater neutrino telescope ANTARES in its 5 line configuration during the period January - September 2007, which coincided with the fifth and first science runs of LIGO and Virgo, respectively. The LIGO-Virgo data were analysed for candidate gravitational-wave signals coincident in time and direction with the neutrino events. No significant coincident events were observed. We place limits on the density of joint high energy neutrino - gravitational wave emission events in the local universe, and compare them with densities of merger and core-collapse events.
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| 3. |
- Adrian-Martinez, S., et al.
(författare)
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The First Combined Search For Neutrino Point-Sources In The Southern Hemisphere With The Antares And Icecube Neutrino Telescopes
- 2016
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Ingår i: Astrophysical Journal. - 0004-637X .- 1538-4357. ; 823:1
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Tidskriftsartikel (refereegranskat)abstract
- We present the results of searches for point-like sources of neutrinos based on the first combined analysis of data from both the ANTARES and IceCube neutrino telescopes. The combination of both detectors, which differ in size and location, forms a window in the southern sky where the sensitivity to point sources improves by up to a factor of 2 compared with individual analyses. Using data recorded by ANTARES from 2007 to 2012, and by IceCube from 2008 to 2011, we search for sources of neutrino emission both across the southern sky and from a preselected list of candidate objects. No significant excess over background has been found in these searches, and flux upper limits for the candidate sources are presented for E-2.5 and E-2 power-law spectra with different energy cut-offs.
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| 4. |
- Petroff, E., et al.
(författare)
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A polarized fast radio burst at low Galactic latitude
- 2017
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Ingår i: Monthly notices of the Royal Astronomical Society. - : Oxford Academic. - 0035-8711 .- 1365-2966. ; 469:4, s. 4465-4482
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Tidskriftsartikel (refereegranskat)abstract
- We report on the discovery of a new fast radio burst (FRB), FRB 150215, with the Parkes radio telescope on 2015 February 15. The burst was detected in real time with a dispersion measure (DM) of 1105.6 +/- 0.8 pc cm(-3), a pulse duration of 2.8(-0.5)(+1.2) ms, and a measured peak flux density assuming that the burst was at beam centre of 0.7(-0.1)(+0.2) Jy. The FRB originated at a Galactic longitude and latitude of 24.66 degrees, 5.28 degrees and 25 degrees away from the Galactic Center. The burst was found to be 43 +/- 5 per cent linearly polarized with a rotation measure (RM) in the range -9 < RM < 12 rad m(-2) (95 per cent confidence level), consistent with zero. The burst was followed up with 11 telescopes to search for radio, optical, X-ray, gamma-ray and neutrino emission. Neither transient nor variable emission was found to be associated with the burst and no repeat pulses have been observed in 17.25 h of observing. The sightline to the burst is close to the Galactic plane and the observed physical properties of FRB 150215 demonstrate the existence of sight lines of anomalously low RM for a given electron column density. The Galactic RM foreground may approach a null value due to magnetic field reversals along the line of sight, a decreased total electron column density from the Milky Way, or some combination of these effects. A lower Galactic DM contribution might explain why this burst was detectable whereas previous searches at low latitude have had lower detection rates than those out of the plane.
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| 5. |
- Ageron, M., et al.
(författare)
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ANTARES : The first undersea neutrino telescope
- 2011
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier. - 0168-9002 .- 1872-9576. ; 656:1, s. 11-38
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Tidskriftsartikel (refereegranskat)abstract
- The ANTARES Neutrino Telescope was completed in May 2008 and is the first operational Neutrino Telescope in the Mediterranean Sea. The main purpose of the detector is to perform neutrino astronomy and the apparatus also offers facilities for marine and Earth sciences. This paper describes the design, the construction and the installation of the telescope in the deep sea, offshore from Toulon in France. An illustration of the detector performance is given. (C) 2011 Elsevier B.V. All rights reserved.
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| 6. |
- Ageron, M., et al.
(författare)
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Studies of a full-scale mechanical prototype line for the ANTARES neutrino telescope and tests of a prototype instrument for deep-sea acoustic measurements
- 2007
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier. - 0168-9002 .- 1872-9576. ; 581:3, s. 695-708
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Tidskriftsartikel (refereegranskat)abstract
- full-scale mechanical prototype line was deployed to a depth of 2500 m to test the leak tightness of the electronics containers and the pressure-resistant properties of an electromechanical cable under evaluation for use in the ANTARES deep-sea neutrino telescope. During a month-long immersion study, line parameter data were taken using miniature autonomous data loggers and shore-based optical time domain reflectometry. Details of the mechanical prototype line, the electromechanical cable and data acquisition are presented. Data taken during the immersion study revealed deficiencies in the pressure resistance of the electromechanical cable terminations at the entry points to the electronics containers. The improvements to the termination, which have been integrated into subsequent detection lines, are discussed. The line also allowed deep-sea acoustic measurements with a prototype hydrophone system. The technical setup of this system is described, and the first results of the data analysis are presented. (c) 2007 Elsevier B.V. All rights reserved.
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| 7. |
- Ageron, M., et al.
(författare)
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The ANTARES optical beacon system
- 2007
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier. - 0168-9002 .- 1872-9576. ; 578:3, s. 498-509
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Tidskriftsartikel (refereegranskat)abstract
- ANTARES is a neutrino telescope being deployed in the Mediterranean Sea. It consists of a three-dimensional array of photomultiplier tubes that can detect the Cherenkov light induced by charged particles produced in the interactions of neutrinos with the surrounding medium. High angular resolution can be achieved, in particular, when a muon is produced, provided that the Cherenkov photons are detected with sufficient timing precision. Considerations of the intrinsic time uncertainties stemming from the transit time spread in the photomultiplier tubes and the mechanism of transmission of light in sea water lead to the conclusion that a relative time accuracy of the order of 0.5 ns is desirable. Accordingly, different time calibration systems have been developed for the ANTARES telescope. In this article, a system based on Optical Beacons, a set of external and well-controlled pulsed light sources located throughout the detector, is described. This calibration system takes into account the optical properties of sea water, which is used as the detection volume of the ANTARES telescope. The design, tests, construction and first results of the two types of beacons, LED and laser-based, are presented. (C) 2007 Elsevier B.V. All rights reserved.
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| 8. |
- Aguilar, J. A., et al.
(författare)
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First results of the instrumentation line for the deep-sea ANTARES neutrino telescope
- 2006
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Ingår i: Astroparticle physics. - : Elsevier. - 0927-6505 .- 1873-2852. ; 26:4-5, s. 314-324
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Tidskriftsartikel (refereegranskat)abstract
- In 2005, the ANTARES Collaboration deployed and operated at a depth of 2500 m a so-called Mini Instrumentation Line equipped with Optical Modules (MILOM) at the ANTARES site. The various data acquired during the continuous operation from April to December 2005 of the MILOM confirm the satisfactory performance of the Optical Modules, their front-end electronics and readout system. as well as the calibration devices of the detector. The in situ measurement of the Optical Module time response yields a resolution better than 0.5 ns. The performance of the acoustic positioning system, which enables the spatial reconstruction of the ANTARES detector with a precision of about 10 cm, is verified. These results demonstrate that with the full ANTARES neutrino telescope the design angular resolution of better than 0.3 degrees can be realistically achieved.
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| 9. |
- Aguilar, J. A., et al.
(författare)
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The data acquisition system for the ANTARES neutrino telescope
- 2007
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier. - 0168-9002 .- 1872-9576. ; 570:1, s. 107-116
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Tidskriftsartikel (refereegranskat)abstract
- The ANTARES neutrino telescope is being constructed in the Mediterranean Sea. It consists of a large three-dimensional array of photo-multiplier tubes. The data acquisition system of the detector takes care of the digitisation of the photo-multiplier tube signals, data transport, data filtering, and data storage. The detector is operated using a control program interfaced with all elements. The design and the implementation of the data acquisition system are described. (c) 2006 Elsevier B.V. All rights reserved.
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| 10. |
- Aguilar, J A, et al.
(författare)
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Study of large hemispherical photomultiplier tubes for the ANTARES neutrino telescope
- 2005
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier. - 0168-9002 .- 1872-9576. ; 555:1-2, s. 132-141
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Tidskriftsartikel (refereegranskat)abstract
- The ANTARES neutrino telescope, to be immersed depth in the Mediterranean Sea, will consist of a three-dimensional matrix of 900 large area photomultiplier tubes housed in pressure-resistant glass spheres. The selection of the optimal photomultiplier was a critical step for the project and required an intensive phase of tests and developments carried out in close collaboration with the main manufacturers worldwide. This paper provides an overview of the tests performed by the collaboration and describes in detail the features of the photomultiplier tube chosen for ANTARES. (c) 2005 Elsevier B.V. All rights reserved.
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| 11. |
- Aguilar, J A, et al.
(författare)
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Transmission of light in deep sea water at the site of the ANTARES neutrino telescope
- 2005
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Ingår i: Astroparticle physics. - : Elsevier. - 0927-6505 .- 1873-2852. ; 23:1, s. 131-155
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Tidskriftsartikel (refereegranskat)abstract
- The ANTARES neutrino telescope is a large photomultiplier array designed to detect neutrino-induced upward-going muons by their Cherenkov radiation. Understanding the absorption and scattering of light in the deep Mediterranean is fundamental to optimising the design and performance of the detector. This paper presents measurements of blue and UV light transmission at the ANTARES site taken between 1997 and 2000. The derived values for the scattering length and the angular distribution of particulate scattering were found to be highly correlated, and results are therefore presented in terms of an absorption length;,ab, and an effective scattering length lambda(sct)(eff). The values for blue (UV) light are found to be lambda(abs) similar or equal to 60(26) m, lambda(sct)(eff similar or equal to) 265(122) m, with significant (similar to15%) time variability. Finally, the results of ANTARES simulations showing the effect of these water properties on the anticipated performance of the detector are presented. (C) 2004 Elsevier B.V. All rights reserved.
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| 12. |
- Ageron, M., et al.
(författare)
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Performance of the first ANTARES detector line
- 2009
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Ingår i: Astroparticle physics. - : Elsevier BV. - 0927-6505 .- 1873-2852. ; 31:4, s. 277-283
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Tidskriftsartikel (refereegranskat)abstract
- In this paper we report on the data recorded with the first Antares detector line. The line was deployed on the 14th of February 2006 and was connected to the readout 2 weeks later. Environmental data for one and a half years of running are shown. Measurements of atmospheric muons from data taken from selected runs during the first 6 months of operation are presented. Performance figures in terms of time residuals and angular resolution are given. Finally the angular distribution of atmospheric muons is presented and from this the depth profile of the muon intensity is derived. (C) 2009 Elsevier B.V. All rights reserved.
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| 13. |
- Shepherd, L., et al.
(författare)
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Infection-related and -unrelated malignancies, HIV and the aging population
- 2016
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Ingår i: HIV Medicine. - : Wiley. - 1464-2662 .- 1468-1293. ; 17:8, s. 590-600
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: HIV-positive people have increased risk of infection-related malignancies (IRMs) and infection-unrelated malignancies (IURMs). The aim of the study was to determine the impact of aging on future IRM and IURM incidence. Methods: People enrolled in EuroSIDA and followed from the latest of the first visit or 1 January 2001 until the last visit or death were included in the study. Poisson regression was used to investigate the impact of aging on the incidence of IRMs and IURMs, adjusting for demographic, clinical and laboratory confounders. Linear exponential smoothing models forecasted future incidence. Results: A total of 15 648 people contributed 95 033 person-years of follow-up, of whom 610 developed 643 malignancies [IRMs: 388 (60%); IURMs: 255 (40%)]. After adjustment, a higher IRM incidence was associated with a lower CD4 count [adjusted incidence rate ratio (aIRR) CD4 count < 200 cells/μL: 3.77; 95% confidence interval (CI) 2.59, 5.51; compared with ≥ 500 cells/μL], independent of age, while a CD4 count < 200 cells/μL was associated with IURMs in people aged < 50 years only (aIRR: 2.51; 95% CI 1.40–4.54). Smoking was associated with IURMs (aIRR: 1.75; 95% CI 1.23, 2.49) compared with never smokers in people aged ≥ 50 years only, and not with IRMs. The incidences of both IURMs and IRMs increased with older age. It was projected that the incidence of IRMs would decrease by 29% over a 5-year period from 3.1 (95% CI 1.5–5.9) per 1000 person-years in 2011, whereas the IURM incidence would increase by 44% from 4.1 (95% CI 2.2–7.2) per 1000 person-years over the same period. Conclusions: Demographic and HIV-related risk factors for IURMs (aging and smoking) and IRMs (immunodeficiency and ongoing viral replication) differ markedly and the contribution from IURMs relative to IRMs will continue to increase as a result of aging of the HIV-infected population, high smoking and lung cancer prevalence and a low prevalence of untreated HIV infection. These findings suggest the need for targeted preventive measures and evaluation of the cost−benefit of screening for IURMs in HIV-infected populations.
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| 14. |
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| 16. |
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| 17. |
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| 18. |
- Neesgaard, B, et al.
(författare)
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How to RESPOND to Modern Challenges for People Living with HIV: A Profile for a New Cohort Consortium
- 2020
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Ingår i: Microorganisms. - : MDPI AG. - 2076-2607. ; 8:8
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Tidskriftsartikel (refereegranskat)abstract
- Background: the International Cohort Consortium of Infectious Disease (RESPOND) is a collaboration dedicated to research on HIV and other infectious diseases. Methods: RESPOND is a flexible organization, with several independent substudies operating under one shared governance. HIV-related variables, including full antiretroviral therapy (ART) history, are collected annually for all participants and merged with substudy specific data into a shared data pool. Incident clinical events are reported using standardized forms. Prospective follow-up started 1/10/17 (enrolment) with retrospective data collected back to 01/01/12. Results: Overall, 17 cohorts from Europe and Australia provided data on 26,258 people living with HIV (PLWH). The majority (43.3%) of the population were white, with men-sex-with-men accounting for 43.3% of the risk for HIV acquisition. The median age was 48 years (IQR 40–56) and 5.2% and 25.5% were known to be co-infected with hepatitis B or C. While 5.3% were ART-naïve, the median duration on ART was 10.1 years (4.8–17.6), with 89.5% having a VL <200 copies/mL and the median CD4 count being 621 cells/µL (438–830). Malignancies (n = 361) and cardiovascular disease (n = 168) were the predominant reported clinical events. Conclusion: RESPOND’s large, diverse study population and standardized clinical endpoints puts the consortium in a unique position to respond to the diverse modern challenges for PLWH.
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| 19. |
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| 20. |
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| 21. |
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| 22. |
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| 24. |
- Wahlstrom, R., et al.
(författare)
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Variations in general practitioners' views of asthma management in four European countries
- 2001
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Ingår i: Social Science and Medicine. - 0277-9536 .- 1873-5347. ; 53:4, s. 507-518
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Tidskriftsartikel (refereegranskat)abstract
- The aim was to identify differences and similarities in views regarding asthma management among general practitioners in four European countries (Germany, Netherlands, Norway and Sweden), and to explore reasons for sub-optimal performance. The results are to be used for the development and tailoring of educational interventions. Semi-structured interviews with 20GPs in each country were conducted and analysed using a phenomenographic approach. The domains of (i) general view of asthma, (ii) the doctor-patient relationship in managing asthma, and (iii) overall management of asthma (treatment goals and evaluation of results) were approached during the interviews. There were different ways of experiencing phenomena related to asthma management both within and between the four countries. Three general views on asthma were found where different perspectives were emphasised: a medical, a 'global' (including community health, social and environmental aspects) and a patient's perspective. Within the medical perspective, only a few German doctors emphasised a psychological aetiology of asthma. The views on the doctor-patient relationship described as 'authoritarian', 'teaching' or 'empowering' occurred similarly in all countries. The majority of the doctors showed confidence in the effectiveness of the pharmaceutical treatment of asthma, some doctors were concerned about limitations, but only in Germany a few doctors were explicitly critical of the values of conventional pharmaceutical treatment. The main treatment goals were either conceived as getting the patient symptom-free (Netherlands, Norway, and Germany) or to control the inflammatory process (Sweden). Several German and some Norwegian doctors expressed the view that patients had to accept the disease and learn how to manage it, while a few German doctors aimed at alternative treatments of asthma. The existence of qualitatively different ways of experiencing asthma management, both in and between countries, calls for consideration when trying to implement general evidence-based treatment guidelines. A variation of approaches in continuing medical education for GPs is needed to address such existing beliefs and conceptions that could sometimes be opposed to the content of educational messages. Copyright © 2001 Elsevier Science Ltd.
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| 25. |
- Briand, Elisabeth, 1979, et al.
(författare)
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An OEGylated thiol monolayer for the tethering of liposomes and the study of liposome interactions
- 2010
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Ingår i: Talanta. - : Elsevier BV. - 0039-9140. ; 81:4-5, s. 1153-1161
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Tidskriftsartikel (refereegranskat)abstract
- The aim of the present work is to develop a protocol for the specific immobilization of liposomes, via tethers, onto functionalized gold surfaces, and in addition to give one example for such a surface architecture All surface functionalization steps are charcerized and controlled First, mixed thiolate self-assembled monolayers (SAMs) prepared from COOH- and OCH3-terminated oligo(ethylene glycol) (OEG) alkane thiols were characterized by polarization modulation reflection absorption infrared spectroscopy (PM-RAIRS) and by X-ray photoemission spectroscopy (XPS). The composition of the mixed SAMs was found to be close to that of the thiol solution. Next, grafting of biotin conjugated with an NH2-terminated OEG spacer (biotin-OEG-NH2) to the COOH groups via conventional amine coupling was optimized with respect to the COOH/OCH3 ratio of the SAM. The grafting of biotin-OEG-NH2 was assessed by monitoring the binding of neutravidin and albumin to the biotinylated surfaces using quartz crystal microbalance with dissipation monitoring (QCM-D), as well as by PM-RAIRS It was shown that a COOH/OCH3 ratio of around 0.3 was sufficient to saturate the SAMs with neutravidin. Finally, tethering of liposomes onto the neutravidin-terminated SAMs. was achieved. As an application example. of a close packed layer of tethered liposomes was exposed to the membrane-penetrating peptide melittin As monitored by QCM-D. the liposomes fused when interacting with the peptide and ruptured into an extended. supported lipid bilayer over the whole surface. In summary, the described surface modification has potential for the development of assays requiring tethered Intact liposomes, or tethered planar bilayers. Such surface architectures are especially important for the study of transmembrane proteins and peptides.
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| 26. |
- Briand, Elisabeth, 1979, et al.
(författare)
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Chemical Modifications of Au/SiO2 Template Substrates for Patterned Biofunctional Surfaces
- 2011
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Ingår i: Langmuir. - : American Chemical Society (ACS). - 1520-5827 .- 0743-7463. ; 27:2, s. 678-685
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this work was to create patterned surfaces for localized and specific biochemical recognition. For this purpose, we have developed a protocol for orthogonal and material-selective surface modifications of microfabricated patterned surfaces composed of SiO2 areas (100 mu m diameter) surrounded by Au. The SiO2 spots were chemically modified by a sequence of reactions (silanization using an amine-terminated silane (APTES), followed by amine coupling of a biotin analogue and biospecific recognition) to achieve efficient immobilization of streptavidin in a functional form. The surrounding Au was rendered inert to protein adsorption by modification by HS(CH2)(10)CONH-(CH2)(2)(OCH2CH2)(7)OH (thiol-OEG). The surface modification protocol was developed by testing separately homogeneous SiO2 and Au surfaces, to obtain the two following results: (i) SiO2 surfaces which allowed the grafting of streptavidin, and subsequent immobilization of biotinylated antibodies, and (ii) Au surfaces showing almost no affinity for the same streptavidin and antibody solutions. The surface interactions were monitored by quartz crystal microbalance with dissipation monitoring (QCM-D), and chemical analyses were performed by polarization modulation-reflexion absorption infrared spectroscopy (PM-RAIRS) and X-ray photoelectron spectroscopy (XPS) to assess the validity of the initial orthogonal assembly of APTES and thiol-OEG. Eventually, microscopy imaging of the modified Au/SiO2 patterned substrates validated the specific binding of streptavidin on the SiO2/APTES areas, as well as the subsequent binding of biotinylated anti-rIgG and further detection of fluorescent rIgG on the functionalized SiO2 areas. These results demonstrate a successful protocol for the preparation of patterned biofunctional surfaces, based on microfabricated Au/SiO2 templates and supported by careful surface analysis. The strong immobilization of the biomolecules resulting from the described protocol is advantageous in particular for micropatterned substrates for cell-surface interactions.
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| 27. |
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| 29. |
- Janin, E, et al.
(författare)
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Hydrogen adsorption on the Pt(111)(root 3x root 5)R30 degrees-Sn surface alloy studied by high resolution core level photoelectron spectroscopy
- 1996
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Ingår i: Applied Surface Science. - : Elsevier BV. - 0169-4332 .- 1873-5584. ; 99:4, s. 371-378
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Tidskriftsartikel (refereegranskat)abstract
- Investigation of the clean and atomic hydrogen covered Pt(111)(root 3 x root 3)R30 degrees-Sn surface alloy has been carried out using high resolution core level photoelectron spectroscopy, The Pt 4(7/2) spectrum recorded from the clean surface alloy shows a single surface peak shifted - 0.25 eV relative to the bulk. Its interpretation by means of a thermodynamical model using Born-Haber cycles confirms the surface alloy model. Adsorption of H does not change the line shape of the Sn 4d core level while a new surface component shifted by 0.59 eV compared to the bulk peak appears in the Pt 4(7/2) spectrum. These results are discussed in the light of the thermodynamical calculations, H atoms are believed to bind only to Pt atoms, and their adsorption site seems to be influenced by the tin present in the surface layer.
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| 30. |
- Lu, H, et al.
(författare)
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Catalytic reduction of nitric oxide over copper Part III : Influence of water vapour
- 1999
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Ingår i: Journal of Molecular Catalysis A. - 1381-1169 .- 1873-314X. ; 138:2-3, s. 227-236
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Tidskriftsartikel (refereegranskat)abstract
- This paper reports on the effect of water vapour on the reduction of NO over copper in the presence of oxygen and isobutene. Reactions were studied at 700 K and at 770 K. Mass spectroscopy (MS) and X-ray photoelectron spectroscopy (XPS) were used to monitor the gas phase composition during reaction and to analyse the catalyst surface, respectively. XPS spectra show that the presence of water vapour influences the Cu oxidation state. At 700 K adsorption of aldehyde is partly blocked by copper oxide resulting in a decrease in the activity of the reaction, although the main mechanism is not changed. At 770 K, water vapour generates an even more oxidised surface, which promotes a complete oxidation of hydrocarbon, the main mechanism of NO reduction is changed, and the activity of the reaction is slightly increased. (C) 1999 Elsevier Science B.V. All rights reserved.
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| 35. |
- Pradier, C.M., et al.
(författare)
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NO reduction by isobutene, in the presence of oxygen, on platinum and copper : a comparative study
- 1996
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Ingår i: Catalysis Today. - : Elsevier BV. - 0920-5861 .- 1873-4308. ; 29:1-4, s. 59-65
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Tidskriftsartikel (refereegranskat)abstract
- The reaction of NO, oxygen and isobutene was studied under conditions close to stoichiometric, on a platinum and on a copper disk in order to better understand the role of each metal, free of any support and dispersion effects. The products of the reaction were analysed by mass spectrometry and an XPS characterization of the surface was carried out at different stages of the reaction. A correlation between the catalytic activity for NO conversion and the presence of adsorbed intermediates has been clearly demonstrated on platinum. On copper, a redox cycle of the metal is necessary to activate the catalyst. On platinum, oxygen is necessary to initiate the reaction, clean the surface and form reactive intermediates; the reaction is strongly sensitive to oxygen concentration, whereas on copper, oxygen does not directly participate in the reaction mechanism.
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