1. |
- Mathews, G. S., et al.
(författare)
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GAS in Protoplanetary Systems (GASPS) I. First results
- 2010
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 518:Article Number: L127
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Tidskriftsartikel (refereegranskat)abstract
- Context. Circumstellar discs are ubiquitous around young stars, but rapidly dissipate their gas and dust on timescales of a few Myr. The Herschel Space Observatory allows for the study of the warm disc atmosphere, using far-infrared spectroscopy to measure gas content and excitation conditions, and far-IR photometry to constrain the dust distribution. Aims. We aim to detect and characterize the gas content of circumstellar discs in four targets as part of the Herschel science demonstration phase. Methods. We carried out sensitive medium resolution spectroscopy and high sensitivity photometry at gimel similar to 60-190 mu m using the Photodetector Array Camera and Spectrometer instrument on the Herschel Space Observatory. Results. We detect [OI] 63 mu m emission from the young stars HD 169142, TW Hydrae, and RECX 15, but not HD 181327. No other lines, including [CII] 158 and [OI] 145, are significantly detected. All four stars are detected in photometry at 70 and 160 mu m. Extensive models are presented in associated papers.
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2. |
- Meeus, G., et al.
(författare)
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Gas in the protoplanetary disc of HD 169142: Herschel's view
- 2010
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 518:Article Number: L124
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Tidskriftsartikel (refereegranskat)abstract
- In an effort to simultaneously study the gas and dust components of the disc surrounding the young Herbig Ae star HD 169142, we present far-IR observations obtained with the PACS instrument onboard the Herschel Space Observatory. This work is part of the open time key program GASPS, which is aimed at studying the evolution of protoplanetary discs. To constrain the gas properties in the outer disc, we observed the star at several key gas-lines, including [OI] 63.2 and 145.5 mu m, [CII] 157.7 mu m, CO 72.8 and 90.2 mu m, and o-H2O 78.7 and 179.5 mu m. We only detect the [OI] 63.2 mu m line in our spectra, and derive upper limits for the other lines. We complement our data set with PACS photometry and (CO)-C-12/13 data obtained with the Submillimeter Array. Furthermore, we derive accurate stellar parameters from optical spectra and UV to mm photometry. We model the dust continuum with the 3D radiative transfer code MCFOST and use this model as an input to analyse the gas lines with the thermo-chemical code ProDIMo. Our dataset is consistent with a simple model in which the gas and dust are well-mixed in a disc with a continuous structure between 20 and 200 AU, but this is not a unique solution. Our modelling effort allows us to constrain the gas-to-dust mass ratio as well as the relative abundance of the PAHs in the disc by simultaneously fitting the lines of several species that originate in different regions. Our results are inconsistent with a gas-poor disc with a large UV excess; a gas mass of 5.0 +/- 2.0 x 10(-3) M-circle dot is still present in this disc, in agreement with earlier CO observations.
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3. |
- Pinte, C., et al.
(författare)
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The Herschel view of GAS in Protoplanetary Systems (GASPS) First comparisons with a large grid of models
- 2010
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 518:Article Number: L126
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Tidskriftsartikel (refereegranskat)abstract
- The Herschel GASPS key program is a survey of the gas phase of protoplanetary discs, targeting 240 objects which cover a large range of ages, spectral types, and disc properties. To interpret this large quantity of data and initiate self-consistent analyses of the gas and dust properties of protoplanetary discs, we have combined the capabilities of the radiative transfer code MCFOST with the gas thermal balance and chemistry code ProDiMo to compute a grid of approximate to 300 000 disc models (DENT). We present a comparison of the first Herschel/GASPS line and continuum data with the predictions from the DENT grid of models. Our objective is to test some of the main trends already identified in the DENT grid, as well as to define better empirical diagnostics to estimate the total gas mass of protoplanetary discs. Photospheric UV radiation appears to be the dominant gas-heating mechanism for Herbig stars, whereas UV excess and/or X-rays emission dominates for T Tauri stars. The DENT grid reveals the complexity in the analysis of far-IR lines and the difficulty to invert these observations into physical quantities. The combination of Herschel line observations with continuum data and/or with rotational lines in the (sub-)millimetre regime, in particular CO lines, is required for a detailed characterisation of the physical and chemical properties of circumstellar discs.
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4. |
- Thi, W. F., et al.
(författare)
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Herschel-PACS observation of the 10 Myr old T Tauri disk TW Hya Constraining the disk gas mass
- 2010
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 518:Article Number: L125
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Tidskriftsartikel (refereegranskat)abstract
- Planets are formed in disks around young stars. With an age of similar to 10 Myr, TW Hya is one of the nearest T Tauri stars that is still surrounded by a relatively massive disk. In addition a large number of molecules has been found in the TW Hya disk, making TW Hya the perfect test case in a large survey of disks with Herschel-PACS to directly study their gaseous component. We aim to constrain the gas and dust mass of the circumstellar disk around TW Hya. We observed the fine-structure lines of [OI] and [CII] as part of the open-time large program GASPS. We complement this with continuum data and ground-based (12) CO 3-2 and (CO)-C-13 3-2 observations. We simultaneously model the continuum and the line fluxes with the 3D Monte-Carlo code MCFOST and the thermo-chemical code ProDiMo to derive the gas and dust masses. We detect the [OI] line at 63 mu m. The other lines that were observed, [OI] at 145 mu m and [CII] at 157 mu m, are not detected. No extended emission has been found. Preliminary modeling of the photometric and line data assuming [(CO)-C-12]/[(CO)-C-13] = 69 suggests a dust mass for grains with radius
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5. |
- Dent, W. R. F., et al.
(författare)
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GASPS-A Herschel Survey of Gas and Dust in Protoplanetary Disks: Summary and Initial Statistics
- 2013
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Ingår i: Publications of the Astronomical Society of the Pacific. - : IOP Publishing. - 0004-6280 .- 1538-3873. ; 125:927, s. 477-505
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Tidskriftsartikel (refereegranskat)abstract
- We describe a large-scale far-infrared line and continuum survey of protoplanetary disk through to young debris disk systems carried out using the ACS instrument on the Herschel Space Observatory. This Open Time Key program, known as GASPS (Gas Survey of Protoplanetary Systems), targeted similar to 250 young stars in narrow wavelength regions covering the [OI] fine structure line at 63 mu m the brightest far-infrared line in such objects. A subset of the brightest targets were also surveyed in [OI]145 mu m, [CII] at 157 mu m, as well as several transitions of H2O and high-excitation CO lines at selected wavelengths between 78 and 180 mu m. Additionally, GASPS included continuum photometry at 70, 100 and 160 mu m, around the peak of the dust emission. The targets were SED Class II-III T Tauri stars and debris disks from seven nearby young associations, along with a comparable sample of isolated Herbig AeBe stars. The aim was to study the global gas and dust content in a wide sample of circumstellar disks, combining the results with models in a systematic way. In this overview paper we review the scientific aims, target selection and observing strategy of the program. We summarise some of the initial results, showing line identifications, listing the detections, and giving a first statistical study of line detectability. The [OI] line at 63 mu m was the brightest line seen in almost all objects, by a factor of similar to 10. Overall [OI]63 mu m detection rates were 49%, with 100% of HAeBe stars and 43% of T Tauri stars detected. A comparison with published disk dust masses (derived mainly from sub-mm continuum, assuming standard values of the mm mass opacity) shows a dust mass threshold for [OI] 63 mu m detection of similar to 10(-5) M-circle dot. Normalising to a distance of 140 pc, 84% of objects with dust masses >= 10(-5) M-circle dot can be detected in this line in the present survey; 32% of those of mass 10(-6)-10(-5) M-circle dot, and only a very small number of unusual objects with lower masses can be detected. This is consistent with models with a moderate UV excess and disk flaring. For a given disk mass, [OI] detectability is lower for M stars compared with earlier spectral types. Both the continuum and line emission was, in most systems, spatially and spectrally unresolved and centred on the star, suggesting that emission in most cases was from the disk. Approximately 10 objects showed resolved emission, most likely from outflows. In the GASPS sample, [OI] detection rates in T Tauri associations in the 0.3-4 Myr age range were similar to 50%. For each association in the 5-20 Myr age range, similar to 2 stars remain detectable in [OI]63 mu m, and no systems were detected in associations with age >20 Myr. Comparing with the total number of young stars in each association, and assuming a ISM-like gas/dust ratio, this indicates that similar to 18% of stars retain a gas-rich disk of total mass similar to 1 M-Jupiter for 1-4 Myr, 1-7% keep such disks for 5-10 Myr, but none are detected beyond 10-20 Myr. The brightest [OI] objects from GASPS were also observed in [OI]145 mu m, [CII]157 mu m and CO J = 18 - 17, with detection rates of 20-40%. Detection of the [CII] line was not correlated with disk mass, suggesting it arises more commonly from a compact remnant envelope.
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6. |
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7. |
- Adler, Jan-Olof, et al.
(författare)
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The upgraded photon tagging facility at the MAX IV Laboratory
- 2013
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - : Elsevier BV. - 0167-5087 .- 0168-9002. ; 715, s. 1-10
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Tidskriftsartikel (refereegranskat)abstract
- A description is given of the upgraded photon tagging facility at the MAX IV Laboratory. Two magnetic spectrometers are used to momentum analyze post-bremsstrahlung electrons. The tagged photon range extends from 10 to 180 MeV with an energy resolution of about 300 keV. The system has been operated at rates up to 4 x 10(6) photons s(-1) MeV (-1). Different diagnostic tools are described as well as the experimental program.
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8. |
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9. |
- Gerkin, RC, et al.
(författare)
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The best COVID-19 predictor is recent smell loss: a cross-sectional study
- 2020
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Ingår i: medRxiv : the preprint server for health sciences. - : Cold Spring Harbor Laboratory.
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- BackgroundCOVID-19 has heterogeneous manifestations, though one of the most common symptoms is a sudden loss of smell (anosmia or hyposmia). We investigated whether olfactory loss is a reliable predictor of COVID-19.MethodsThis preregistered, cross-sectional study used a crowdsourced questionnaire in 23 languages to assess symptoms in individuals self-reporting recent respiratory illness. We quantified changes in chemosensory abilities during the course of the respiratory illness using 0-100 visual analog scales (VAS) for participants reporting a positive (C19+; n=4148) or negative (C19-; n=546) COVID-19 laboratory test outcome. Logistic regression models identified singular and cumulative predictors of COVID-19 status and post-COVID-19 olfactory recovery.ResultsBoth C19+ and C19-groups exhibited smell loss, but it was significantly larger in C19+ participants (mean±SD, C19+: -82.5±27.2 points; C19-: -59.8±37.7). Smell loss during illness was the best predictor of COVID-19 in both single and cumulative feature models (ROC AUC=0.72), with additional features providing negligible model improvement. VAS ratings of smell loss were more predictive than binary chemosensory yes/no-questions or other cardinal symptoms, such as fever or cough. Olfactory recovery within 40 days was reported for ∼50% of participants and was best predicted by time since illness onset.ConclusionsAs smell loss is the best predictor of COVID-19, we developed the ODoR-19 tool, a 0-10 scale to screen for recent olfactory loss. Numeric ratings ≤2 indicate high odds of symptomatic COVID-19 (4<OR<10), which can be deployed when viral lab tests are impractical or unavailable.
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10. |
- Sims, D. A., et al.
(författare)
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(γ,n) study of the isovector quadrupole resonance in 40Ca
- 1997
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Ingår i: Physical Review C: covering nuclear physics. - 2469-9985. ; 55:3, s. 1288-1294
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Tidskriftsartikel (refereegranskat)abstract
- The forward-to-backward asymmetry of neutrons emitted in the 40Ca(γ,n0) reaction was measured at photon energies in the range of 27–50 MeV. An energy-dependent asymmetry was observed that is interpreted as evidence of interference between the isovector quadrupole resonance and the giant dipole resonance. Data analysis in terms of semiclassical and direct-semidirect models estimate the isovector quadrupole resonance to be at an excitation energy of 31.0±1.5 MeV, with a width of 16.0±1.5 MeV, and exhausting most of the energy-weighted sum rule for the isovector quadrupole resonance.
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11. |
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12. |
- Klug, G., et al.
(författare)
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The therapist variable : Is it still an unknown factor? [Die Therapeutenvariable
- 2008
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Ingår i: Psychotherapeut (Berlin). - : Springer Science and Business Media LLC. - 0935-6185 .- 1432-2080. ; 53:2, s. 83-91
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Tidskriftsartikel (refereegranskat)abstract
- The objective of this study was to investigate the therapeutic attitude as a self-contained dimension of the therapeutic process. The psychotherapists' beliefs and attitudes in therapeutic matters are measured according to the Therapeutic Attitude Scales (TASC) of the Therapeutic Attitude Questionnaire (ThAt) and were applied to investigate the therapist variable. The investigation concentrated on the therapist's belief in the curative value of a number of ingredients of psychotherapy, on the therapist's individual style of conducting psychotherapy and on basic assumptions about the nature of psychotherapy and the nature of the human mind. A total of 451 psychotherapists (81 psychodynamic psychotherapists, 208 psychoanalytic psychotherapists and 162 behaviour therapists) were investigated. There were highly significant differences between the three groups of therapists, a finding which is in line with the basic theory. Adaptation and insight of the assumed curative factors as well as supportiveness and neutrality of the technique factors, differentiate the groups highly significantly. The multivariate analysis underlines the importance of adaptation and insight to differentiate between all groups. The results by and large confirm the general assumptions held on the differences between the groups. Thus the ThAt appears to be a valid instrument to grasp more subtle features of the therapist variable that may influence the outcome of psychotherapy. © 2008 Springer Medizin Verlag.
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14. |
- Laureati, M., et al.
(författare)
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Individual differences in texture preferences among European children : Development and validation of the Child Food Texture Preference Questionnaire (CFTPQ)
- 2020
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Ingår i: Food Quality and Preference. - : Elsevier BV. - 0950-3293 .- 1873-6343. ; 80
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Tidskriftsartikel (refereegranskat)abstract
- Texture has an important role in children’s acceptance and rejection of food. However, little is known about individual differences in texture preference. The aim of this study was to develop and validate a child-friendly tool to explore individual differences in texture preferences in school-aged children from six European countries (Austria, Finland, Italy, Spain, Sweden and United Kingdom). Six hundred and ten children aged 9–12 years and their parents participated in a cross-sectional study. Children completed the Child Food Texture Preference Questionnaire (CFTPQ) and a Food Neophobia Scale (FNS). The CFTPQ consisted in asking children to choose the preferred item within 17 pairs of pictures of food varying in texture (hard vs. soft or smooth vs. lumpy). Children also evaluated all food items for familiarity. Parents completed the CFTPQ regarding their preferred items, a food frequency questionnaire for their child, and provided background information. For a subset of children, a re-test was done for the CFTPQ and FNS to assess reliability. The results showed that the tool was child-friendly, had high test-retest reliability, and identified country-related differences as well as segments of children with different texture preferences (hard- vs. soft-likers). These segments differed in consumption frequency of healthy foods, and in food neophobia.
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15. |
- Proserpio, C., et al.
(författare)
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Cross-national differences in child food neophobia : A comparison of five European countries
- 2020
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Ingår i: Food Quality and Preference. - : Elsevier BV. - 0950-3293 .- 1873-6343. ; 81
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Tidskriftsartikel (refereegranskat)abstract
- Food neophobia (FN) has been extensively explored, especially in children. However, very few studies have compared this food behavior in children from different countries. Considering the clear diversity between European countries in feeding practices and food consumption, it is important to deepen the understanding of cross-national differences in child FN. The aim of this study was to explore and compare FN in five European countries (Finland, Italy, Spain, Sweden and UK) using a food neophobia scale specifically designed for children. Five hundred and twenty-nine children (54% girls) aged 9–12 years were recruited from schools in each country and were asked to complete the Italian Child Food Neophobia Scale (ICFNS, Laureati, Bergamaschi et al., 2015), which was translated into each respective language. Parents (n ≈ 300) completed a food consumption frequency questionnaire for their child, and provided background information. Reliability of the tool was assessed through internal consistency and temporal stability. Total internal consistency was 0.76. When calculated by country, internal consistency was satisfactory (Cronbach’s alpha >0.70) for all countries. FN was negatively associated to fruit and vegetable consumption, liking of wholegrain biscuits, and timing of introduction of semi-solid food. There were small but significant cross-national differences in FN with British and Swedish children being the most neophobic and significantly higher in FN than Finnish children, who were the most neophilic. Results indicate that the tool can be successfully used in all the tested countries with children in the age range of 9–12 years. The tool can be useful to measure the effects of interventions aiming at changing food behaviors, such as reducing FN, among children.
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16. |
- Rad, M. G., et al.
(författare)
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Influence of charged impurities on the surface phases of Sn/Ge(111)
- 2001
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Ingår i: Surface Science. - 0039-6028 .- 1879-2758. ; 477:03-feb, s. 227-234
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Tidskriftsartikel (refereegranskat)abstract
- The root3 alpha and 3 x 3 reconstructions on the Ge(111)-Sn surface have been perturbed by small amounts of iodine and potassium to test the spectral response in the course of a synchrotron radiation photoemission study. We demonstrate the inadequacy of the static model of the root3 alpha phase at room temperature and of the surface charge density wave model of the 3 x 3 phase at low temperature. Instead, the influence of the charged impurities is consistently explained when considering that dynamical fluctuations in the tin adatom positions are frozen in upon passing the phase transition temperature.
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17. |
- Akkurt, I, et al.
(författare)
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Photoneutron yields from tungsten in the energy range of the giant dipole resonance
- 2003
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Ingår i: Physics in Medicine and Biology. - : IOP Publishing. - 1361-6560 .- 0031-9155. ; 48:20, s. 3345-3352
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Tidskriftsartikel (refereegranskat)abstract
- Photoneutron production on the nuclei of high-Z components of medical accelerator heads can lead to a significant secondary dose during a course of bremsstrahlung radiotherapy, However, a quantitative evaluation of secondary neutron dose requires improved data on the photoreaction yields. These have been measured as a function of photon energy, neutron energy and neutron angle for W-nat, using tagged photons at the MAX-Lab photonuclear facility in Sweden. This work presents neutron yields for W-nat(gamma, n) and compares these with the predictions of the Monte Carlo code MCNP-GN, developed specifically to simulate photoneutron production at medical accelerators.
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18. |
- Avendano, Esteban, et al.
(författare)
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Coloration Mechanism in Proton-Intercalated Electrochromic Hydrated NiOy and Ni1-xVxOy Thin Films
- 2009
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Ingår i: Journal of the Electrochemical Society. - : The Electrochemical Society. - 0013-4651 .- 1945-7111. ; 156:8, s. p132-p138
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Tidskriftsartikel (refereegranskat)abstract
- Electrochromic (EC) films of nickel oxide, with and without vanadium, were prepared by reactive dc magnetron sputtering. They were characterized by electrochemical and optical measurements and studied by X-ray photoelectron spectroscopy (PES) using synchrotron radiation. The films were analyzed under as-deposited conditions and after bleaching/coloration by insertion/extraction of protons from a basic solution and ensuing charge stabilization. Optical measurements were consistent with a coloration process due to charge-transfer transitions from Ni2+ to Ni3+ states. The PES measurements showed a higher concentration of Ni3+ in the colored films. Moreover, two peaks were present in the O 1s spectra of the bleached film and pointed to contributions of Ni(OH)(2) and NiO. The changes in the O 1s spectra upon coloration treatment indicate the presence of Ni2O3 in the colored film and necessitated an extension of the conventional model for the mechanism of EC coloration. The model involves not only proton extraction from nickel hydroxide to form nickel oxyhydroxide but also participation of NiO in the coloration process to form Ni2O3.
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19. |
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20. |
- Brun, Eva, et al.
(författare)
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Early prediction of treatment outcome in head and neck cancer with 2-18FDG PET
- 1997
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Ingår i: Acta Oncologica. - : Informa UK Limited. - 1651-226X .- 0284-186X. ; 36:7, s. 741-747
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Tidskriftsartikel (refereegranskat)abstract
- The development of alternative treatment regimens in clinical oncology has increased the need for early prediction of cancer therapy outcome. The aim of this study was, early in the treatment phase, to identify patients with advanced head and neck cancer, responding or not responding to initiated therapy. The tumour metabolic rate of glucose (MRgl) examined by 2-18FDG-PET was determined in 17 patients before and after the first weeks of either radiotherapy (16-35 Gy) or one course of combination chemotherapy. Metabolic values uptake values normalized to plasma activity integrals--were correlated to loco-regional outcome, as evaluated 5-6 weeks after completion of treatment. Initial low tumour MRgl (<20 micromol/min/100 g tissue), in primary lesions or regional metastases, predicted a local complete response. When a high initial tumour MRgl was found, the magnitude of the reduction of MRgl in the second PET examination might be an adjunct in predicting local tumour response.
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21. |
- Brun, Eva, et al.
(författare)
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FDG PET studies during treatment: Prediction of therapy outcome in head and neck squamous cell carcinoma.
- 2002
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Ingår i: Head and Neck. - : Wiley. - 1043-3074. ; 24:2, s. 127-135
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Positron emission tomography (PET) provides metabolic information of tissues in vivo. The purpose of this study was to assess the value of PET with 2-[(18) F] fluoro-2-deoxy-D-glucose (FDG) in prediction of therapy outcome (tumor response, survival, and locoregional control) in locally advanced HNSCC. METHODS: Between 1993 and 1999 47 patients underwent PET before (PET(1)) and after (PET(2)) 1 to 3 weeks of radical treatment with evaluation of metabolic rate (MR) and standardized uptake value (SUV) of FDG. All patients received radiotherapy, and 10 also received neoadjuvant chemotherapy. Median follow-up time was 3.3 years. RESULTS: Low and high MR FDG at PET(2), with median value as cutoff, was associated with complete remission in 96% and 62% (p =.007), with 5-year overall survival in 72% and 35% (p =.0042) and with local control in 96% and 55% (p =.002), respectively. CONCLUSIONS: FDG PET in the early phase of treatment of HNSCC is associated with tumor response, survival, and local control. Copyright 2002 John Wiley & Sons, Inc.
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22. |
- Bruun, Måns, et al.
(författare)
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Polygynous male starlings allocate parental effort according to relative hatching date
- 1997
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Ingår i: Animal Behaviour. - : Elsevier BV. - 1095-8282 .- 0003-3472. ; 54, s. 73-79
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Tidskriftsartikel (refereegranskat)abstract
- In many polygynous bird species, males allocate most of their parental effort to their primary females’ broods. There are several hypotheses that may explain this: the relative reproductive value of the brood, the energetic demand of the brood, the genetic quality of the female and the certainty of fatherhood may all be higher for the primary females’ broods. Since these parameters may covary in nature, experiments are necessary to determine their importance. Bigynous male European starlings,Sturnus vulgarispredominantly incubated the eggs and fed the nestlings of their primary females. In an experiment we altered the order in which the clutches hatched by exchanging the primary and secondary females’ eggs before hatching. Even though experimental males mostly incubated their primary females’ clutches, they predominantly fed the nestlings of the secondary female. Experimental males fed secondary females’ nestlings significantly more than control males did. In fact, experimental males invested in their secondary females’ broods to the same extent as control males invested in their primary females’ broods. This result demonstrates that males use relative brood age to decide how to allocate their parental effort between their broods which has important implications for the evolution of the starling mating system.
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23. |
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25. |
- Fredelius, G, et al.
(författare)
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Who should receive subsidized psychotherapy? : Analysis of decision makers' think-aloud protocols
- 2002
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Ingår i: Qualitative Health Research. - 1049-7323 .- 1552-7557. ; 12:5, s. 640-654
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Tidskriftsartikel (refereegranskat)abstract
- Three groups of judges representing clinical, political, and laypersons' perspectives were given the task of prioritizing patients for subsidized psychotherapy within the Swedish health care system. The authors documented the judges' decision-making processes in think-aloud protocols and analyzed them qualitatively, focusing on the conflict between the urgency of a case and its suitability for treatment. In an earlier statistical analysis of the same material, clinicians had seemed to pay more attention to suitability criteria, whereas health care officials and laypersons prioritized based oil urgency. The qualitative findings confirmed the centrality of this conflict and contributed to a deeper understanding of decision makers' ways of coping with it. Their conceptions of suitability and urgency were also elucidated by analysis of the think-aloud protocols.
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26. |
- Gerkin, Richard C., et al.
(författare)
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Recent Smell Loss Is the Best Predictor of COVID-19 Among Individuals With Recent Respiratory Symptoms
- 2021
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Ingår i: Chemical Senses. - : Oxford University Press (OUP). - 0379-864X .- 1464-3553. ; 46
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Tidskriftsartikel (refereegranskat)abstract
- In a preregistered, cross-sectional study, we investigated whether olfactory loss is a reliable predictor of COVID-19 using a crowdsourced questionnaire in 23 languages to assess symptoms in individuals self-reporting recent respiratory illness. We quantified changes in chemosensory abilities during the course of the respiratory illness using 0–100 visual analog scales (VAS) for participants reporting a positive (C19+; n = 4148) or negative (C19−; n = 546) COVID-19 laboratory test outcome. Logistic regression models identified univariate and multivariate predictors of COVID-19 status and post-COVID-19 olfactory recovery. Both C19+ and C19− groups exhibited smell loss, but it was significantly larger in C19+ participants (mean ± SD, C19+: −82.5 ± 27.2 points; C19−: −59.8 ± 37.7). Smell loss during illness was the best predictor of COVID-19 in both univariate and multivariate models (ROC AUC = 0.72). Additional variables provide negligible model improvement. VAS ratings of smell loss were more predictive than binary chemosensory yes/no-questions or other cardinal symptoms (e.g., fever). Olfactory recovery within 40 days of respiratory symptom onset was reported for ~50% of participants and was best predicted by time since respiratory symptom onset. We find that quantified smell loss is the best predictor of COVID-19 amongst those with symptoms of respiratory illness. To aid clinicians and contact tracers in identifying individuals with a high likelihood of having COVID-19, we propose a novel 0–10 scale to screen for recent olfactory loss, the ODoR-19. We find that numeric ratings ≤2 indicate high odds of symptomatic COVID-19 (4 < OR < 10). Once independently validated, this tool could be deployed when viral lab tests are impractical or unavailable.
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27. |
- Gorgoi, M, et al.
(författare)
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The high kinetic energy photoelectron spectroscopy facility at BESSY progress and first results
- 2009
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 601:1-2, s. 48-53
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Tidskriftsartikel (refereegranskat)abstract
- Photoelectron spectroscopy at high kinetic energy is a research field that receives an increasing interest due to the possibility of studying bulk properties of materials and deeply buried interfaces. Recently the high kinetic energy electron (HIKE) spectroscopy facility at BESSY in Berlin has become operative at the bending magnet beamline KMC-1. The first results show very good performance. Electron spectra have been recorded using X-ray energies from 2 keV up to 12 keV. Using back-scattering conditions in the crystal monochromator, very high-resolution has been achieved for photon energies around 2, 6 and 8 keV. In the latter case, spectra with a resolving power from the monochromator of >= 80 000 have been achieved and it has been possible to perform electron spectroscopy with resolving power of >= 60 000, yielding a total instrument resolution of about 150 meV as determined directly from spectra. This paper describes the facility and reports some of the first results. (C) 2009 Elsevier B.V. All rights reserved.
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28. |
- Grankvist, R, et al.
(författare)
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Myocardial micro-biopsy procedure for molecular characterization with increased precision and reduced trauma
- 2020
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Ingår i: Scientific reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 10:1, s. 8029-
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Tidskriftsartikel (refereegranskat)abstract
- Endomyocardial biopsy is a valuable tool in cardiac diagnostics but is limited by low diagnostic yield and significant complication risks. Meanwhile, recent developments in transcriptomic and proteomic technologies promise a wealth of biological data from minimal tissue samples. To take advantage of the minimal tissue amount needed for molecular analyses, we have developed a sub-millimeter endovascular biopsy device, considerably smaller than current clinical equipment, and devised a low-input RNA-sequencing protocol for analyzing small tissue samples. In in vivo evaluation in swine, 81% of biopsy attempts (n = 157) were successful. High quality RNA-sequencing data was generated from 91% of the sequenced cardiac micro-biopsy samples (n = 32). Gene expression signatures of samples taken with the novel device were comparable with a conventional device. No major complications were detected either during procedures or during 7 days’ follow-up, despite acquiring a relatively large number of biopsies (median 30) in each animal. In conclusion, the novel device coupled with RNA-sequencing provides a feasible method to obtain molecular data from the myocardium. The method is less traumatic and has a higher flexibility compared to conventional methods, enabling safer and more targeted sampling from different parts of the myocardium.
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29. |
- Grehk, Mikael, et al.
(författare)
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Initial stages of metal-organic chemical-vapor deposition of ZrO2 on a FeCrAl alloy
- 2008
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Ingår i: Thin Solid Films. - Amsterdam : Elsevier BV. - 0040-6090 .- 1879-2731. ; 516:6, s. 875-879
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Tidskriftsartikel (refereegranskat)abstract
- The initial stages of metal-organic chemical-vapor deposition of ZrO2 on a model FeCrAl alloy was investigated using synchrotron radiation photoelectron spectroscopy, X-ray absorption spectroscopy, scanning Auger microprobe, and time of flight secondary mass spectrometry. The coatings were grown in ultra-high vacuum at 400 degrees C and 800 degrees C using the single source precursor zirconium tetra-tert-butoxide. At 400 degrees C the coatings mainly consist of tetragonal ZrO2 and at 800 degrees C a mixed ZrO2/Al2O3 layer is formed. The Al metal diffuses from the FeCrAl bulk to the metal/coating interface at 400 degrees C and to the surface of the coating at 800 degrees C. The result indicates that the reaction mechanism of the growth process is different at the two investigated temperatures.
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30. |
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31. |
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32. |
- Hormann-Wallner, Marlies, et al.
(författare)
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Intake of Fibre-Associated Foods and Texture Preferences in Relation to Weight Status Among 9-12 Years Old Children in 6 European Countries
- 2021
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Ingår i: Frontiers in Nutrition. - : Frontiers Media S.A.. - 2296-861X. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Plant foods, rich in fibre, can offer textures that children find difficult to orally manipulate, resulting in low preferences but are important for a healthy diet and prevention of overweight in children. Our aim was to investigate preferences for food texture, intake of fibre-associated foods and the relation to BMI. Three hundred thirty European children (9-12 years, 54% female) indicated their texture preferences using the Child-Food-Texture-Preference- Questionnaire (CFTPQ), and their parents responded on fibre-associated food consumption and anthropometric information. BMI was significantly lower for children with higher intake of wholegrain alternatives of common foods; in addition to being significantly influenced by country and the wearing of a dental brace. Overall BMI-for-age-percentiles (BMI_pct) were negatively associated with the consumption of wholegrain cereals, white pasta and wholemeal products and positively associated with the intake of legumes and white biscuits. In males, BMI_pct were negatively associated with wholegrain products and dried fruits, and in females, positively with legume consumption. A few country-related associations were found for BMI_pct and wholegrain biscuits, seeds and nuts and refined products. No overall correlation was found between BMI_pct and the texture preference of soft/hard foods by CFTPQ, except in Austria. We conclude that this study revealed evidence of a connection between fibre-associated foods and children's BMI at a cross-cultural level and that sex is an important determinant of fibre-associated food intake and the development of overweight in childhood.
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33. |
- Johansson, E. M. J., et al.
(författare)
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Interface electronic states and molecular structure of a triarylamine based hole conductor on rutile TiO2(110)
- 2008
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Ingår i: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 128, s. 184709-
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Tidskriftsartikel (refereegranskat)abstract
- The molecular and electronic surface structure of a triarylamine based hole-conductor (HC) molecule evaporated onto rutile TiO2(110) single crystal is investigated by means of synchrotron light based photoelectron spectroscopy and x-ray absorption spectroscopy in combination with calculations based on density functional theory. Different amounts of the HC molecule was evaporated spanning the monolayer to multilayer region. The molecular surface structure is investigated and the results indicate that no specific covalent chemical bonding is formed and that the plane formed by the different nitrogens in the HC molecules has a rather small angle versus the TiO2 substrate surface plane. Some molecular ordering also persists in the multilayer region. The experimental core level spectra, valence level spectra, and the N 1s x-ray absorption spectroscopy spectra are well modeled by calculations on an individual molecule. Interestingly, the formation of the TiO2/HC interface results in significant binding energy shifts in core levels and valence levels shifting all peaks of a the HC material to the same extent. Smaller shifts were also observed in the substrate core level peaks. The shift is discussed in terms of nanoscale energy level bending and final state hole screening. With respect to electronic applications, specifically in a solid state dye-sensitized solar cell, it is argued that the observed energy level alignment at the TiO2/HC interface can act as a hole trap.
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34. |
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35. |
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36. |
- Karlsson, P G, et al.
(författare)
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Interfacial properties of the nanostructured dye-sensitized solid heterojunction TiO2/RuL2(NCS)(2)/CuI
- 2004
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Ingår i: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 120:23, s. 11224-11232
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Tidskriftsartikel (refereegranskat)abstract
- The interfaces of the nanostructured dye-sensitized solid heterojunction TiO2/Ru-dye/CuI have been studied using photoelectron spectroscopy of core and valence levels, x-ray absorption spectroscopy and atomic force microscopy. A nanostructured anatase TiO2 film sensitized with RuL2(NCS)(2) [cis-bis(4,4'-dicarboxy-2,2'-bipyridine)-bis(isothio-cyanato)-ruthenium(II)] was prepared in a controlled way using a novel combined in-situ and ex-situ (Ar atmosphere) method. Onto this film CuI was deposited in-situ. The formation of the dye-CuI interface and the changes brought upon the dye-TiO2 interface could be monitored in a stepwise fashion. A direct interaction between the dye NCS groups and the CuI is evident in the core level photoelectron spectra. Concerning the energy matching of the valence electronic levels, the photoelectron spectra indicate that the dye HOMO overlaps in energy with the Cu 3d-I 5p hydrid states. The CuI grow in the form of particles, which at the initial stages displace the dye molecules causing dye-TiO2 bond breaking. Consequently, the very efficient charge injection channel provided by the dye-TiO2 carboxylic bonding is directly affected for a substantial part of the dye molecules. This may be of importance for the functional properties of such a heterojunction. (C) 2004 American Institute of Physics.
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37. |
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38. |
- Karlsson, P. G., et al.
(författare)
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Metal organic chemical vapor deposition of ultrathin ZrO2 films on Si(1 0 0) and Si(1 1 1) studied by electron spectroscopy
- 2007
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Ingår i: Surface Science. - 0039-6028 .- 1879-2758. ; 601:4, s. 1008-1018
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Tidskriftsartikel (refereegranskat)abstract
- The growth of ultrathin ZrO2 films on Si(100)-(2x1) and Si(111)-(7x7) has been studied with core level photoelectron spectroscopy and X-ray absorption spectroscopy. The films were deposited sequentially by chemical vapor deposition in ultra-high vacuum using zirconium tetra-tert-butoxide as precursor. Deposition of a > 50Å thick film leads in both cases to tetragonal ZrO2 (t-ZrO2), whereas significant differences are found for thinner films. On Si(111)-(7x7) the local structure of t-ZrO2 is not observed until a film thickness of 51Å is reached. On Si(100)-(2x1) the local geometric structure of t-ZrO2 is formed already at a film thickness of 11Å. The higher tendency for the formation of t-ZrO2 on Si(100) is discussed in terms of Zr–O valence electron matching to the number of dangling bonds per surface Si atom. The Zr–O hybridization within the ZrO2 unit depends furthermore on the chemical composition of the surrounding. The precursor t-butoxy ligands undergo efficient C–O scission on Si(100), leaving carbonaceous fragments embedded in the interfacial layer. In contrast, after small deposits on Si(111) stable t-butoxy groups are found. These are consumed upon further deposition. Stable methyl and, possibly, also hydroxyl groups are found on both surfaces within a wide film thickness range.
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39. |
- Karlsson, P. G., et al.
(författare)
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Metal organic chemical vapor deposition of ultrathin ZrO2 films on Si(100) and Si(111) studied by electron spectroscopy
- 2007
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Ingår i: Surface Science. - : Elsevier BV. - 0039-6028 .- 1879-2758. ; 601:4, s. 1008-1018
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Tidskriftsartikel (refereegranskat)abstract
- The growth of ultrathin ZrO2 films on Si(100)-(2 x 1) and Si(111)-(7 x 7) has been studied with core level photoelectron spectroscopy and X-ray absorption spectroscopy. The films were deposited sequentially by chemical vapor deposition in ultra-high vacuum using zirconium tetra-tert-butoxide as precursor. Deposition of a > 50 angstrom thick film leads in both cases to tetragonal ZrO2 (t-ZrO2), whereas significant differences are found for thinner films. On Si(111)-(7 x 7) the local structure of t-ZrO2 is not observed until a film thickness of 51 angstrom is reached. On Si(100)-(2 x 1) the local geometric structure of t-ZrO2 is formed already at a film thickness of 11 angstrom. The higher tendency for the formation of t-ZrO2 on Si(100) is discussed in terms of Zr-O valence electron matching to the number of dangling bonds per surface Si atom, The Zr-O hybridization within the ZrO2 unit depends furthermore on the chemical composition of the surrounding. The precursor t-butoxy ligands undergo efficient C-O scission on Si(100), leaving carbonaceous fragments embedded in the interfacial layer. In contrast, after small deposits on Si(111) stable t-butoxy groups are found. These are consumed upon further deposition. Stable methyl and, possibly, also hydroxyl groups are found on both surfaces within a wide film thickness range. (c) 2006 Elsevier B.V. All rights reserved.
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40. |
- Karlsson, P. G., et al.
(författare)
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TiO2 chemical vapor deposition on Si(111) in ultrahigh vacuum: Transition from interfacial phase to crystalline phase in the reaction limited regime
- 2011
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Ingår i: Surface Science. - : Elsevier BV. - 0039-6028 .- 1879-2758. ; 605:13-14, s. 1147-1156
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Tidskriftsartikel (refereegranskat)abstract
- The interaction between the metal organic precursor molecule titanium(IV) isopropoxide (TTIP) and three different surfaces has been studied: Si(111)-(7 x 7), SiOx/Si(111) and TiO2. These surfaces represent the different surface compositions encountered during TTIP mediated TiO2 chemical vapor deposition on Si(111). The surface chemistry of the titanium(IV) isopropoxide precursor and the film growth have been explored by core level photoelectron spectroscopy and x-ray absorption spectroscopy using synchrotron radiation. The resulting film morphology has been imaged with scanning tunneling microscopy. The growth rate depends on both surface temperature and surface composition. The behavior can be rationalized in terms of the surface stability of isopropoxy and isopropyl groups, confirming that growth at 573 K is a reaction limited process. (C) 2011 Elsevier B.V. All rights reserved.
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41. |
- Karlsson, P G, et al.
(författare)
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UHV-MOCVD growth of TiO2 on SiOx/Si(111): Interfacial properties reflected in the Si 2p photoemission spectra
- 2005
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Ingår i: Surface Science. - : Elsevier BV. - 0039-6028 .- 1879-2758. ; 580:1-3, s. 207-217
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Tidskriftsartikel (refereegranskat)abstract
- Metal-organic chemical vapour deposition growth of titanium oxide on moderately pre-oxidised Si(1 1 1) using the titanium(IV) isopropoxide precursor has been studied for two different growth modes, reaction-limited growth at 300 degrees C and flux-limited growth at 500 degrees C. The interfacial properties have been characterized by monitoring synchrotron radiation excited Si 2p photoemission spectra. The cross-linking from oxidised Si to bulk Si after TTIP exposure has been found to be very similar to that of SiOx/Si(1 1 1). However, the results show that the additional oxidation of Si most probably causes a corrugation of the SiOx/Si interface. Those conclusions are valid for both growth modes. A model is introduced in which the amorphous interface region is described as (TiO2)(x)(SiO2)(y) where x and y changes linearly and continuously over the interface. The model quantifies how (TiO2)(x)(SiO2)(y) mixing changes the relative intensities of the signals from silicon oxide and silicon. The method can be generalised and used for the analyses of other metal-oxides on silicon. (c) 2005 Elsevier B.V. All rights reserved.
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42. |
- Karlsson, P.G., et al.
(författare)
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Ultrathin ZrO2 films on Si-rich SiC(0 0 0 1)-(3 × 3) : Growth and thermal stability
- 2007
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Ingår i: Surface Science. - : Elsevier BV. - 0039-6028 .- 1879-2758. ; 601:11, s. 2390-2400
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Tidskriftsartikel (refereegranskat)abstract
- The growth and thermal stability of ultrathin ZrO2 films on the Si-rich SiC(0 0 0 1)-(3 × 3) surface have been explored using photoelectron spectroscopy (PES) and X-ray absorption spectroscopy (XAS). The films were grown in situ by chemical vapor deposition using the zirconium tetra tert-butoxide (ZTB) precursor. The O 1s XAS results show that growth at 400 °C yields tetragonal ZrO2. An interface is formed between the ZrO2 film and the SiC substrate. The interface contains Si in several chemically different states. This gives evidence for an interface that is much more complex than that formed upon oxidation with O2. Si in a 4+ oxidation state is detected in the near surface region. This shows that intermixing of SiO2 and ZrO2 occurs, possibly under the formation of silicate. The alignment of the ZrO2 and SiC band edges is discussed based on core level and valence PES spectra. Subsequent annealing of a deposited film was performed in order to study the thermal stability of the system. Annealing to 800 °C does not lead to decomposition of the tetragonal ZrO2 (t-ZrO2) but changes are observed within the interface region. After annealing to 1000 °C a laterally heterogeneous layer has formed. The decomposition of the film leads to regions with t-ZrO2 remnants, metallic Zr silicide and Si aggregates. © 2007 Elsevier B.V. All rights reserved.
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43. |
- Karlsson, P. G., et al.
(författare)
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Ultrathin ZrO2 films on Si-rich SiC(0001)-(3x3): Growth and thermal stability
- 2007
-
Ingår i: Surface Science. - : Elsevier BV. - 0039-6028. ; 601:11, s. 2390-2400
-
Tidskriftsartikel (refereegranskat)abstract
- The growth and thermal stability of ultrathin ZrO2 films on the Si-rich Si(0001)-(3 x 3) surface have been explored using photoelectron spectroscopy (PES) and X-ray absorption spectroscopy (XAS). The films were grown in situ by chemical vapor deposition using the zirconium tetra tert-butoxide (ZTB) precursor. The O 1s XAS results show that growth at 400 degrees C yields tetragonal ZrO2. An interface is formed between the ZrO2 film and the SiC substrate. The interface contains Si in several chemically different states. This gives evidence for an interface that is much more complex than that formed upon oxidation with O-2. Si in a 4+ oxidation state is detected in the near surface region. This shows that intermixing of SiO2 and ZrO2 occurs, possibly under the formation of silicate. The alignment of the ZrO2 and SiC band edges is discussed based on core level and valence PES spectra. Subsequent annealing of a deposited film was performed in order to study the thermal stability of the system. Annealing to 800 degrees C does not lead to decomposition of the tetragonal ZrO2 (t-ZrO2) but changes are observed within the interface region. After annealing to 1000 degrees C a laterally heterogeneous layer has formed. The decomposition of the film leads to regions with t-ZrO2 remnants, metallic Zr silicide and Si aggregates. (c) 2007 Elsevier B.V. All rights reserved.
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44. |
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45. |
- Lindborg, Regina, et al.
(författare)
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Naturbetesmarker – en resurs för biologisk mångfald och ekosystemtjänster.
- 2021
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Ingår i: Biologisk mångfald, naturnyttor och ekosystemtjänster. Svenska perspektiv på livsviktiga framtidsfrågor. - 9789188083357 - 9789188083364 ; :121, s. 169-177
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Vårt traditionella jordbrukslandskap är centralt för att bevara biologisk mångfald, men det moderna jordbruket har medfört förändringar som bidragit till en utarmning av mångfalden. Detta hotar de ekosystemtjänster som naturbetesmarker och deras mångfald kan bidra med. Sverige har i tusentals år haft betesdjur som en integrerad del av matproduktionen, vilket har format landskap med en variation av åkrar, ängs- och betesmarker och skog. Våra svenska ängar och betesmarker är idag bland de artrikaste miljöerna i världen. Genom att bibehålla brukandet av naturbetesmarkerna som en del i det moderna jordbrukssystemet ökar möjligheten att producera mat på ett hållbart sätt och samtidigt gynna biologisk mångfald och ekosystemtjänster.
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46. |
- Oleszkiewicz, A., et al.
(författare)
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Hedonic perception of odors in children aged 5–8 years is similar across 18 countries : Preliminary data
- 2022
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Ingår i: International Journal of Pediatric Otorhinolaryngology. - : Elsevier BV. - 0165-5876 .- 1872-8464. ; 157
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Olfactory preference emerges very early in life, and the sense of smell in children rapidly develops until the second decade of life. It is still unclear whether hedonic perception of odors is shared in children inhabiting different regions of the globe.Methods: Five-hundred ten healthy children (N = 510; ngirls = 256; nboys = 254) aged from 5 to 8 years from 18 countries rated the pleasantness of 17 odors.Results: The hedonic perception of odors in children aged between 5 and 8 years was rather consistent across 18 countries and mainly driven by the qualities of an odor and the overall ability of children to label odorants.Conclusion: Conclusions from this study, being a secondary analysis, are limited to the presented set of odors that were initially selected for the development of U-Sniff test and present null findings for the cross-cultural variability in hedonic perception of odors across 18 countries. These two major issues should be addressed in the future to either contradict or replicate the results presented herewith. This research lays fundament for posing further research questions about the developmental aspects of hedonic perception of odors and opens a new door for investigating cross-cultural differences in chemosensory perception of children.
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47. |
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48. |
- Parma, Valentina, et al.
(författare)
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More Than Smell—COVID-19 Is Associated With Severe Impairment of Smell, Taste, and Chemesthesis
- 2020
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Ingår i: Chemical Senses. - : Oxford University Press (OUP). - 0379-864X .- 1464-3553. ; 45:7, s. 609-622
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Tidskriftsartikel (refereegranskat)abstract
- Recent anecdotal and scientific reports have provided evidence of a link between COVID-19 and chemosensory impairments, such as anosmia. However, these reports have downplayed or failed to distinguish potential effects on taste, ignored chemesthesis, and generally lacked quantitative measurements. Here, we report the development, implementation, and initial results of a multilingual, international questionnaire to assess self-reported quantity and quality of perception in 3 distinct chemosensory modalities (smell, taste, and chemesthesis) before and during COVID-19. In the first 11 days after questionnaire launch, 4039 participants (2913 women, 1118 men, and 8 others, aged 19–79) reported a COVID-19 diagnosis either via laboratory tests or clinical assessment. Importantly, smell, taste, and chemesthetic function were each significantly reduced compared to their status before the disease. Difference scores (maximum possible change ±100) revealed a mean reduction of smell (−79.7 ± 28.7, mean ± standard deviation), taste (−69.0 ± 32.6), and chemesthetic (−37.3 ± 36.2) function during COVID-19. Qualitative changes in olfactory ability (parosmia and phantosmia) were relatively rare and correlated with smell loss. Importantly, perceived nasal obstruction did not account for smell loss. Furthermore, chemosensory impairments were similar between participants in the laboratory test and clinical assessment groups. These results show that COVID-19-associated chemosensory impairment is not limited to smell but also affects taste and chemesthesis. The multimodal impact of COVID-19 and the lack of perceived nasal obstruction suggest that severe acute respiratory syndrome coronavirus strain 2 (SARS-CoV-2) infection may disrupt sensory-neural mechanisms.
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49. |
- Reinstrup, Peter, et al.
(författare)
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Regional cerebral metabolic rate (positron emission tomography) during inhalation of nitrous oxide 50% in humans
- 2008
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Ingår i: British Journal of Anaesthesia. - : Elsevier BV. - 1471-6771 .- 0007-0912. ; 100:1, s. 66-71
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Recent studies in man have shown that cerebral blood flow increases during inhalation of nitrous oxide (N2O), a finding which is believed to be a result of an increased cerebral metabolic rate (CMR). However, this has not previously been evaluated in man. METHODS: Regional CMR(glu) (rCMR(glu)) was measured three dimensionally with positron emission tomography (PET) after injection of 2-(18F)fluoro-2-deoxy-D-glucose in 10 spontaneously breathing men (mean age 31 yr) inhaling either N2O 50% in O2 30% or O2 30% in N2. RESULTS: Global CMR(glu) in young men was 27 (3) micromol 100 g(-1) min(-1) [mean (SD)]. Inhalation of N2O 50% did not change global CMR(glu) [30 (5) micromol 100 g(-1) min(-1)] significantly, but it changed the distribution of the metabolism in the brain (P<0.0001 analysis of variance). Compared with inhalation of O2 30% in N2, N2O 50% inhalation increased the metabolism in the basal ganglia [14 (17)%, P<0.05] and thalamus [22 (23) %, P<0.05]. There was a prolonged metabolic effect of N2O inhalation seen on a succeeding PET scan with oxygen-enriched air (P<0.0001) performed 1 h after the N2O administration. CONCLUSIONS: Inhalation of N2O 50% did not change global CMR(glu), but the metabolism increased in central brain structures, an effect that was still present 1 h after discontinuation of N2O.
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50. |
- Richter, Jan Hinnerk, et al.
(författare)
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Band alignment at the ZrO2/Si(100) interface studied by photoelectron and x-ray absorption spectroscopy
- 2007
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 101:10
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Tidskriftsartikel (refereegranskat)abstract
- We present measurements of the Zr and Si core level photoelectron binding energies relative to the Fermi level and the vacuum level under a ZrO2 growth series on Si(100). It is shown that the Zr core level binding energy is most properly referenced to the local vacuum level already from the monolayer regime. This confirms the insulating properties of ZrO2. The Si core levels are referenced to the Fermi level and undergo shifts consistent with the disappearance of the mid-band-gap states originating from the (2×1) reconstruction on the clean Si(100) surface. The use of O 1s x-ray absorption spectroscopy (XAS) to determine the location of the conduction band edge of ZrO2 is discussed with the aid of ab initio calculations. It is demonstrated that the conduction band edge is located at the XAS peak position and that the position relative to the valence band can be determined by aligning the O 1s XAS spectrum to the O 1s photoelectron spectrum. The study thus establishes that photoelectron spectroscopy in conjunction with x-ray absorption spectroscopy forms a most powerful tool for studies of the band alignment at metal oxide-silicon interfaces.
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