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Sökning: WFRF:(Witt Georg)

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1.
  • Amare, Azmeraw, et al. (författare)
  • Association of Polygenic Score and the involvement of Cholinergic and Glutamatergic Pathways with Lithium Treatment Response in Patients with Bipolar Disorder.
  • 2023
  • Ingår i: Research square. - : Research Square Platform LLC.
  • Tidskriftsartikel (refereegranskat)abstract
    • Lithium is regarded as the first-line treatment for bipolar disorder (BD), a severe and disabling mental disorder that affects about 1% of the population worldwide. Nevertheless, lithium is not consistently effective, with only 30% of patients showing a favorable response to treatment. To provide personalized treatment options for bipolar patients, it is essential to identify prediction biomarkers such as polygenic scores. In this study, we developed a polygenic score for lithium treatment response (Li+PGS) in patients with BD. To gain further insights into lithium's possible molecular mechanism of action, we performed a genome-wide gene-based analysis. Using polygenic score modeling, via methods incorporating Bayesian regression and continuous shrinkage priors, Li+PGS was developed in the International Consortium of Lithium Genetics cohort (ConLi+Gen: N=2,367) and replicated in the combined PsyCourse (N=89) and BipoLife (N=102) studies. The associations of Li+PGS and lithium treatment response - defined in a continuous ALDA scale and a categorical outcome (good response vs. poor response) were tested using regression models, each adjusted for the covariates: age, sex, and the first four genetic principal components. Statistical significance was determined at P<����������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������.
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2.
  • Amare, Azmeraw T, et al. (författare)
  • Association of polygenic score and the involvement of cholinergic and glutamatergic pathways with lithium treatment response in patients with bipolar disorder.
  • 2023
  • Ingår i: Molecular psychiatry. - 1476-5578. ; 28
  • Tidskriftsartikel (refereegranskat)abstract
    • Lithium is regarded as the first-line treatment for bipolar disorder (BD), a severe and disabling mental health disorder that affects about 1% of the population worldwide. Nevertheless, lithium is not consistently effective, with only 30% of patients showing a favorable response to treatment. To provide personalized treatment options for bipolar patients, it is essential to identify prediction biomarkers such as polygenic scores. In this study, we developed a polygenic score for lithium treatment response (Li+PGS) in patients with BD. To gain further insights into lithium's possible molecular mechanism of action, we performed a genome-wide gene-based analysis. Using polygenic score modeling, via methods incorporating Bayesian regression and continuous shrinkage priors, Li+PGS was developed in the International Consortium of Lithium Genetics cohort (ConLi+Gen: N = 2367) and replicated in the combined PsyCourse (N = 89) and BipoLife (N = 102) studies. The associations of Li+PGS and lithium treatment response - defined in a continuous ALDA scale and a categorical outcome (good response vs. poor response) were tested using regression models, each adjusted for the covariates: age, sex, and the first four genetic principal components. Statistical significance was determined at P < 0.05. Li+PGS was positively associated with lithium treatment response in the ConLi+Gen cohort, in both the categorical (P = 9.8 × 10-12, R2 = 1.9%) and continuous (P = 6.4 × 10-9, R2 = 2.6%) outcomes. Compared to bipolar patients in the 1st decile of the risk distribution, individuals in the 10th decile had 3.47-fold (95%CI: 2.22-5.47) higher odds of responding favorably to lithium. The results were replicated in the independent cohorts for the categorical treatment outcome (P = 3.9 × 10-4, R2 = 0.9%), but not for the continuous outcome (P = 0.13). Gene-based analyses revealed 36 candidate genes that are enriched in biological pathways controlled by glutamate and acetylcholine. Li+PGS may be useful in the development of pharmacogenomic testing strategies by enabling a classification of bipolar patients according to their response to treatment.
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3.
  • Andersson, Patrik U, 1970, et al. (författare)
  • Carbon dioxide interactions with crystalline and amorphous ice surfaces
  • 2004
  • Ingår i: Journal of Physical Chemistry A. - : American Chemical Society (ACS). - 1089-5639 .- 1520-5215. ; 108:21, s. 4627-4631
  • Tidskriftsartikel (refereegranskat)abstract
    • Carbon dioxide interactions with crystalline and amorphous water ice have been studied by time-resolved molecular beam techniques. CO2 collisions at thermal kinetic energies with ice in the temperature range 100-160 K result in efficient trapping on the ice surface followed by desorption. The desorption kinetics on crystalline ice at 100-125 K are well described by the Arrhenius equation with an activation energy of 0.22 +/- 0.02 eV and a preexponential factor of 10(13.32+/-0.57) s(-1). Below 120 K, CO2 populates strongly bonded sites on amorphous ice, resulting in surface residence times on the order of minutes at 100 K, and the desorption data can in this case not be explained by a simple first-order process. The results are compared to previous studies of gas-ice interactions, and the implications for heterogeneous processes in the terrestrial atmosphere are discussed.
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4.
  • Enell, Carl-Fredrik, et al. (författare)
  • The Hotel Payload 2 campaign : Overview of NO, O and electron density measurements in the upper mesosphere and lower thermosphere
  • 2011
  • Ingår i: Journal of Atmospheric and Solar-Terrestrial Physics. - : Elsevier BV. - 1364-6826 .- 1879-1824. ; 73:14-15, s. 2228-2236
  • Tidskriftsartikel (refereegranskat)abstract
    • The ALOMAR eARI Hotel Payload 2 (HotPay 2) rocket campaign took place at Andoya Rocket Range, Norway, in January 2008. The rocket was launched on January 31, 2008 at 19:14 UT, when auroral activity appeared after a long geomagnetically quiet period. In this paper we present an overview of the HotPay 2 measurements of upper mesospheric and lower thermospheric (UMLT) electron, atomic oxygen (O) and nitric oxide (NO) densities. [O] and [NO] were retrieved from a set of three photometers, Night-Time Emissions from the Mesosphere and Ionosphere (NEMI). Faraday rotation receivers on the rocket and the EISCAT UHF incoherent scatter radar provided simultaneous electron density profiles, whereas the ALOMAR Na lidar and meteor radar measured the temperature profile and wind. The aurora was also observed with ground-based imagers. The retrieved oxygen number density profile has a maximum at 89 km, some 10 km lower than expected from earlier measurements and modelled profiles based on climatological averages (such as the MSIS model), and the retrieved NO densities are also lower than the expected. Satellite measurements indicate that subsidence over the winter pole controlled the densities. Quantitative chemistry model results based on climatological average atmospheric density and temperature profiles were, therefore, not in good agreement with the measured profiles. The Hotel Payload 2 measurements thus confirm the importance of downward transport from the thermosphere into the winter polar vortex.
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5.
  • Guineva, V, et al. (författare)
  • Lyman-alpha Detector Designed for Rocket Measurements of the Direct Solar Radiation at 121.5 nm
  • 2007
  • Ingår i: Bulgarian Journal of Physics. - 1310-0157 .- 1314-2666. ; 34:2, s. 116-127
  • Tidskriftsartikel (refereegranskat)abstract
    • Rocket measurements of the direct Lyman-alpha radiation penetrating in the atmosphere were planned during the HotPay I rocket experiment, June 2006, Project ASLAF (Attenuation of the Solar Lyman-Alpha Flux), Andøya Rocket Range (ARR), Norway. The basic goal of ASLAF project was the study of the processes in the summer mesosphere and thermosphere (up to 110 km), at high latitudes using the Lyman-alpha measurements. The resonance transition 2P-2S of the atomic hydrogen (Lyman-alpha emission) is the strongest and most conspicuous feature in the solar EUV spectrum. Due to the favorable circumstance, that the Lyman-alpha wavelength (121.5 nm) coincides with a minimum of the O2 absorption spectrum, the direct Lyman-alpha radiation penetrates well in the mesosphere. The Lyman-alpha radiation is the basic agent of the NO molecules ionization, thus generating the ionospheric D-layer, and of the water vapour photolysis, being one of the main H2O loss processes. The Lyman-alpha radiation transfer depends on the resonance scattering from the hydrogen atoms in the atmosphere and on the O2 absorption. Since the Lyman-alpha extinction in the atmosphere is a measure for the column density of the oxygen molecules, the atmospheric temperature profile can be calculated thereof. The detector of solar Lyman-alpha radiation was manufactured in the Stara Zagora Department of the Solar-Terrestrial Influences Laboratory (STIL). Its basic part is an ionization chamber, filled in with NO. A 60 V power supply is applied to the chamber. The produced photoelectric current from the sensor is fed to a 2-channels amplifier, providing an analog signal. The characteristics of the Lyman-alpha detector were studied. It passed successfully all tests and the results showed that the instrument could be used in rocket experiments to measure the Lyman-alpha flux. From the measurements of the detector, the Lyman-alpha vertical profile can be obtained. The forthcoming scientific data analysis will include radiative transfer simulations, O2 density, atmospheric power and temperature profiles retrieval as well as comparison with other parameters, measured near the polar summer mesopause and study of the processes in this region. 
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6.
  • Guineva, V., et al. (författare)
  • O-2 density and temperature profiles retrieving from direct solar Lyman-alpha radiation measurements
  • 2009
  • Ingår i: Geomagnetism and Aeronomy. - 0016-7932 .- 1555-645X. ; 49:8, s. 1292-1295
  • Tidskriftsartikel (refereegranskat)abstract
    • The resonance transition P-2-S-2 of the atomic hydrogen (Lyman-alpha emission) is the strongest and most conspicuous feature in the solar EUV spectrum. The Lyman-alpha radiation transfer depends on the resonance scattering from the hydrogen atoms in the atmosphere and on the O-2 absorption. Since the Lyman-alpha extinction in the atmosphere is a measure for the column density of the oxygen molecules, the atmospheric O-2 density and temperature profiles can be calculated thereof. A detector of solar Lyman-alpha radiation was manufactured in the Stara Zagora Department of the Solar-Terrestrial Influences Laboratory (STIL). Its basic part is an ionization camera, filled in with NO. A 60 V power supply is applied to the chamber. The produced photoelectric current from the sensor is fed to a two-channel amplifier, providing analog signal. The characteristics of the Lyman-alpha detector were studied. It passed successfully all tests and the results showed that the so-designed instrument could be used in rocket experiments to measure the Lymanalpha flux. From the measurements of the detector, the Lyman-alpha vertical profile can be obtained. Programs are created to compute the O-2 density, atmospheric power and temperature profiles based on Lymanalpha data. The detector design appertained to ASLAF project (Attenuation of the Solar Lyman-Alpha Flux), a scientific cooperation between STIL-Bul.Acad.Sci., Stara Zagora Department and the Atmospheric Physics Group at the Department of Meteorology (MISU), Stockholm University, Sweden. The joint project was part of the rocket experiment HotPay I, in the ALOMAR eARI Project, EU's 6th Framework Programme, Andoya Rocket Range, Andenes, Norway. The project is partly financed by the Bulgarian Ministry of Science and Education.
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7.
  • Gumbel, Jörg, et al. (författare)
  • Retrieval of global mesospheric sodium densities from the Odin satellite
  • 2007
  • Ingår i: Geophysical Research Letters. - 0094-8276 .- 1944-8007. ; 34:L04813
  • Tidskriftsartikel (refereegranskat)abstract
    • Satellite observations of the Na D dayglow at 589 nm provide a global database for the climatology of the mesospheric sodium layer. More than five years of Na D limb observations are available from the Optical Spectrograph and InfraRed Imager System onboard the Odin satellite. We describe a robust retrieval method that provides individual sodium density profiles with a typical accuracy of 20% and altitude resolution of 2 km. Retrieved column abundances and density profiles are validated against sodium resonance lidar measurements at mid- latitudes. Examples of the seasonal and latitudinal variation of the sodium layer illustrate Odin's potential for climatological studies of mesospheric metals.
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8.
  • Gumbel, Jörg, et al. (författare)
  • The MATS satellite mission - gravity wave studies by Mesospheric Airglow/Aerosol Tomography and Spectroscopy
  • 2020
  • Ingår i: Atmospheric Chemistry And Physics. - : COPERNICUS GESELLSCHAFT MBH. - 1680-7316 .- 1680-7324. ; 20:1, s. 431-455
  • Tidskriftsartikel (refereegranskat)abstract
    • Global three-dimensional data are a key to understanding gravity waves in the mesosphere and lower thermosphere. MATS (Mesospheric Airglow/Aerosol Tomography and Spectroscopy) is a new Swedish satellite mission that addresses this need. It applies space-borne limb imaging in combination with tomographic and spectroscopic analysis to obtain gravity wave data on relevant spatial scales. Primary measurement targets are O-2 atmospheric band dayglow and nightglow in the near infrared, and sunlight scattered from noctilucent clouds in the ultraviolet. While tomography provides horizontally and vertically resolved data, spectroscopy allows analysis in terms of mesospheric temperature, composition, and cloud properties. Based on these dynamical tracers, MATS will produce a climatology on wave spectra during a 2-year mission. Major scientific objectives include a characterization of gravity waves and their interaction with larger-scale waves and mean flow in the mesosphere and lower thermosphere, as well as their relationship to dynamical conditions in the lower and upper atmosphere. MATS is currently being prepared to be ready for a launch in 2020. This paper provides an overview of scientific goals, measurement concepts, instruments, and analysis ideas.
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9.
  • Hedin, Jonas, 1976-, et al. (författare)
  • Observations of NO in the upper mesosphere and lower thermosphere during ECOMA 2010
  • 2012
  • Ingår i: Annales Geophysicae. - : Copernicus GmbH. - 0992-7689 .- 1432-0576. ; 30:11, s. 1611-1621
  • Tidskriftsartikel (refereegranskat)abstract
    • In December 2010 the last campaign of the German-Norwegian sounding rocket project ECOMA (Existence and Charge state Of Meteoric smoke particles in the middle Atmosphere) was conducted from Andøya Rocket Range in northern Norway (69° N, 16° E) in connection with the Geminid meteor shower. The main instrument on board the rocket payloads was the ECOMA detector for studying meteoric smoke particles (MSPs) by active photoionization and subsequent detection of the produced charges (particles and photoelectrons). In addition to photoionizing MSPs, the energy of the emitted photons from the ECOMA flash-lamp is high enough to also photoionize nitric oxide (NO). Thus, around the peak of the NO layer, at and above the main MSP layer, photoelectrons produced by the photoionization of NO are expected to contribute to, or even dominate above the main MSP-layer, the total measured photoelectron current. Among the other instruments on board was a set of two photometers to study the O2(b1Σg+−X3Σg-) Atmospheric band and NO2 continuum nightglow emissions. In the absence of auroral emissions, these two nightglow features can be used together to infer NO number densities. This will provide a way to quantify the contribution of NO photoelectrons to the photoelectron current measured by the ECOMA instrument and, above the MSP layer, a simultaneous measurement of NO with two different and independent techniques. This work is still on-going due to the uncertainties, especially in the effort to quantitatively infer NO densities from the ECOMA photoelectron current, and the lack of simultaneous measurements of temperature and density for the photometric study. In this paper we describe these two techniques to infer NO densities and discuss the uncertainties. The peak NO number density inferred from the two photometers on ascent was 3.9 × 108 cm−3 at an altitude of about 99 km, while the concentration inferred from the ECOMA photoelectron measurement at this altitude was a factor of 5 smaller.
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10.
  • Hedin, Jonas, et al. (författare)
  • Optical studies of noctilucent clouds in the extreme ultraviolet
  • 2008
  • Ingår i: Annales Geophysicae. - 0992-7689 .- 1432-0576. ; 26:5, s. 1109-1119
  • Tidskriftsartikel (refereegranskat)abstract
    • In order to better understand noctilucent clouds (NLC) and their sensitivity to the variable environment of the polar mesosphere, more needs to be learned about the actual cloud particle population. Optical measurements are today the only means of obtaining information about the size of mesospheric ice particles. In order to efficiently access particle sizes, scattering experiments need to be performed in the Mie scattering regime, thus requiring wavelengths of the order of the particle size. Previous studies of NLC have been performed at wavelengths down to 355 nm from the ground and down to about 200 nm from rockets and satellites. However, from these measurements it is not possible to access the smaller particles in the mesospheric ice population. This current lack of knowledge is a major limitation when studying important questions about the nucleation and growth processes governing NLC and related particle phenomena in the mesosphere. We show that NLC measurements in the extreme ultraviolet, in particular using solar Lyman-α radiation at 121.57 nm, are an efficient way to further promote our understanding of NLC particle size distributions. This applies both to global measurements from satellites and to detailed in situ studies from sounding rockets. Here, we present examples from recent rocket-borne studies that demonstrate how ambiguities in the size retrieval at longer wavelengths can be removed by invoking Lyman-α. We discuss basic requirements and instrument concepts for future rocket-borne NLC missions. In order for Lyman-α radiation to reach NLC altitudes, high solar elevation and, hence, daytime conditions are needed. Considering the effects of Lyman-α on NLC in general, we argue that the traditional focus of rocket-borne NLC missions on twilight conditions has limited our ability to study the full complexity of the summer mesopause environment.
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