| 1. |
- Barendregt, Wolmet, et al.
(författare)
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Lessons from the Evaluation of Game for Developing Number Sense
- 2013
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Ingår i: Chi 2013 Workshop.
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Konferensbidrag (refereegranskat)abstract
- In this paper we describe the methodological lessons that we learned from the evaluation of Fingu, an iPad game to help children between 4 and 7 years old to develop number sense through use of their fingers. We pay attention to the recruitment of the teachers and children, the selection of the measurement instruments, the distribution of the game to the children, handling a group of testers, and controlling of the use of the game during the study.
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| 2. |
- Björneholm, Olle, et al.
(författare)
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Deeper Insight into Depth-Profiling of Aqueous Solutions Using Photoelectron Spectroscopy
- 2014
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Ingår i: Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 118:50, s. 29333-29339
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Tidskriftsartikel (refereegranskat)abstract
- X-ray photoelectron spectroscopy (XPS) is widely used to probe properties such as molecular stoichiometry, microscopic distributions relative to the surface by so-called depth-profiling, and molecular orientation. Such studies usually rely on the core-level photoionization cross sections being independent of molecular composition. The validity of this assumption has recently been questioned, as a number of gas-phase molecules have been shown to exhibit photon-energy-dependent nonstochiometric intensity oscillations arising from EXAFS-like modulations of the photoionization cross section. We have studied this phenomenon in trichloroethanol in both gas phase and dissolved in water. The gas-phase species exhibits pronounced intensity oscillations, similar to the ones observed for other gas-phase molecules. These oscillations are also observed for the dissolved species, implying that the effect has to be taken into account when performing depth-profiling experiments of solutions and other condensed matter systems. The similarity between the intensity oscillations for gas phase and dissolved species allows us to determine the photoelectron kinetic energy of maximum surface sensitivity, approximate to 100 eV, which lies in the range of pronounced intensity oscillations.
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| 3. |
- Eriksson, Susanna K., et al.
(författare)
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Solvent Dependence of the Electronic Structure of I- and I-3(-)
- 2014
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Ingår i: Journal of Physical Chemistry B. - : American Chemical Society (ACS). - 1520-6106 .- 1520-5207. ; 118:11, s. 3164-3174
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Tidskriftsartikel (refereegranskat)abstract
- We present synchrotron-based I4d photoelectron spectroscopy experiments of solutions from LiI and LiI3 in water, ethanol, and acetonitrile. The experimentally determined solvent-induced binding energy shifts (SIBES) for the monatomic I- anion are compared to predictions from simple Born theory, PCM calculations, as well as multiconfigurational quantum chemical spectral calculations from geometries obtained through molecular dynamics of solvated clusters. We show that the SIBES for I- explicitly depend on the details of the hydrogen bonding configurations of the solvent to the I- and that static continuum models such as the Born model cannot capture the trends in the SIBES observed both in experiments and in higher-level calculations. To extend the discussion to more complex polyatomic anions, we also performed experiments on I-3(-) and I-/I-3(-) mixtures in different solvents and the results are analyzed in the perspective of SIBES. The experimental SIBES values indicate that the solvation effects even for such similar anions as I- and I-3(-) can be rather different in nature.
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| 4. |
- Josefsson, Ida, et al.
(författare)
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Collective hydrogen-bond dynamics dictates the electronic structure of aqueous I-3(-)
- 2013
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Ingår i: Physical Chemistry, Chemical Physics - PCCP. - : Royal Society of Chemistry (RSC). - 1463-9076 .- 1463-9084. ; 15:46, s. 20189-20196
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Tidskriftsartikel (refereegranskat)abstract
- The molecular and electronic structures of aqueous I-3 and I ions have been investigated through ab initio molecular dynamics (MD) simulations and photoelectron (PE) spectroscopy of the iodine 4d core levels. Against the background of the theoretical simulations, data from our I4d PE measurements are shown to contain evidence of coupled solute-solvent dynamics. The MD simulations reveal large amplitude fluctuations in the I-I distances, which couple to the collective rearrangement of the hydrogen bonding network around the I-3(-) ion. Due to the high polarizability of the I-3(-) ion, the asymmetric I-I vibration reaches partially dissociated configurations, for which the electronic structure resembles that of I-2 + I-. The charge localization in the I-3(-) ion is found to be moderated by hydrogen-bonding. As seen in the PE spectrum, these soft molecular vibrations are important for the electronic properties of the I-3(-) ion in solution and may play an important role in its electrochemical function.
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| 5. |
- Kimbung, Siker, et al.
(författare)
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Co-targeting of the PI3K pathway improves the response of BRCA1 deficient breast cancer cells to PARP1 inhibition.
- 2012
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Ingår i: Cancer Letters. - : Elsevier BV. - 1872-7980 .- 0304-3835. ; 319:2, s. 232-241
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Tidskriftsartikel (refereegranskat)abstract
- Although pre-clinical and clinical studies on PARP1 inhibitors, alone and in combination with DNA-damaging agents, show promising results, further ways to improve and broaden the scope of application of this therapeutic approach are warranted. To this end, we have investigated the possibility of improving the response of BRCA1 mutant breast cancer cells to PARP1 inhibition by co-targeting the PI3K pathway. Human breast cancer cell lines with or without the expression of BRCA1 and/or PTEN were treated with PARP1 and PI3K inhibitors as single agents and in combination. PARP1 inhibition induced DNA damage conferring a G2/M arrest and decrease in viability, paralleled by the induction of apoptosis. PI3K inhibition alone caused a G1 arrest and decreased cell growth. Most importantly, sequential combination of PARP and PI3K inhibitors interacted synergistically to significantly decrease growth compared to PARP inhibition alone. Global transcriptional profiling revealed that this decrease in growth was associated with down-regulation of macromolecule biosynthesis and the induction of apoptosis. Taken together, these results suggest an improved treatment strategy for BRCA1-mutant and possibly also triple-negative breast cancers with similar molecular defects.
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| 6. |
- Ottosson, Mikael, et al.
(författare)
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Arbetsrehabilitering och myndighetssamverkan : Utvärdering av Samordningsförbundet i Svedala
- 2010
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Ett i den politiska debatten centralt område är arbetsrehabilitering. Inom detta område går det att se en ökad politisk aktivitet som många gånger mynnar ut i begreppet ”samverkan”. Ropet på samverkan beror möjligen på att det blir allt svårare för enskilda myndigheter att såväl överblicka som hantera sitt verksamhetsfält i takt med att omvärlden ter sig allt mer komplex. Föreliggande rapport bygger på en utvärdering av Samordningsförbundet i Svedala utförd av Mikael Ottosson och Niklas Sandell. Mikael Ottosson är historiker och verksam på Centrum för tillämpad arbetslivsforskning (CTA) vid Malmö högskola och Niklas Sandell är företagsekonom och verksam på Rådet för KommunalEkonomisk Forskning och Utbildning (KEFU) vid Lunds universitet. Utvärderingens primära syfte är att belysa Samordningsförbundet i Svedala som det såg ut vid slutet av 2009. Utvärderingen fokuserar fyra områden: syfte och mål, organisation, innehåll och effektivitet.
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| 7. |
- Ottosson, Niklas, 1981-
(författare)
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Aqueous Solutions as seen through an Electron Spectrometer : Surface Structure, Hydration Motifs and Ultrafast Charge Delocalization Dynamics
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In spite of their high abundance and importance, aqueous systems are enigmatic on the microscopic scale. In order to obtain information about their geometrical and electronic structure, simple aqueous solutions have been studied experimentally by photo- and Auger electron spectroscopy using the novel liquid micro-jet technique in conjunction with synchrotron radiation. The thesis is thematically divided into three parts. In the first part we utilize the surface sensitivity of photoelectron spectroscopy to probe the distributions of solutes near the water surface. In agreement with recent theoretical predictions we find that large polarizable anions, such as I- and ClO4-, display enhanced surface propensities compared to smaller rigid ions. Surface effects arising from ion-ion interactions at higher electrolyte concentrations and as function of pH are investigated. Studies of linear mono-carboxylic acids and benzoic acid show that the neutral molecular forms of such weak acids are better stabilized at the water surface than their respective conjugate base forms. The second part examines what type of information core-electron spectra can yield about the chemical state and hydration structure of small organic molecules in water. We demonstrate that the method is sensitive to the protonation state of titratable functional groups and that core-level lineshapes are dependent on local water hydration configurations. Using a combination of photoelectron and X-ray absorption spectroscopy we also show that the electronic re-arrangement upon hydrolysis of aldehydes yields characteristic fingerprints in core-level spectra. In the last part of this thesis we study ultrafast charge delocalization dynamics in aqueous solutions using resonant and off-resonant Auger spectroscopy. Intermolecular Coulombic decay (ICD) is found to occur in a number of core-excited solutions where excess energy is transferred between the solvent and the solute. The rate of ultrafast electron delocalization between hydrogen bonded water molecules upon oxygen 1s resonant core-excitation is found to decrease upon solvation of inorganic ions. The presented work is illustrative of how core-level photoelectron spectroscopy can be valuable in the study of fundamental phenomena in aqueous solutions.
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| 8. |
- Ottosson, Niklas, et al.
(författare)
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Cations Strongly Reduce Electron Hopping-Times in Aqueous Solutions
- 2011
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Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 133:34, s. 13489-13495
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Tidskriftsartikel (refereegranskat)abstract
- We study how the ultrafast electron transfer between H2O molecules in liquid water upon absorption of soft X-ray radiation depends on the local molecular binding environment. Our probe is the resonant Auger-decay of the water O1s core-hole (~3.6 fs), by which we show that efficiency for electron delocalization can be significantly reduced when a first-shell water molecule is replaced by an atomic ion. Decays resulting from excitations at the O1s post-edge feature (~540 eV) of 6m LiBr and 3m MgBr2 aqueous solutions reveal electron hopping-times of approximately 1.5 and 1.9 fs, respectively – the latter represents a four-fold increase compared to the corresponding value in neat water. The slower electron delocalization in electrolytes, which shows a strong dependence on the charge of the cations, can be explained by ion-induced reduction of water-water orbital mixing. Density functional theory (DFT) electronic structure calculations of solvation geometries obtained from molecular dynamics simulations reveal that this phenomenon largely arises from electrostatic perturbations of ions on the solvating water molecules. Our results demonstrate that it is possible to deliberately manipulate charge-transfer rates in aqueous media.
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| 9. |
- Ottosson, Niklas, et al.
(författare)
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Increased Propensity of I-aq(-) for the Water Surface in Non-neutral Solutions : Implications for the Interfacial Behavior of H3Oaq+ and OHaq-
- 2011
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Ingår i: The Journal of Physical Chemistry Letters. - : American Chemical Society (ACS). - 1948-7185. ; 2:9, s. 972-976
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Tidskriftsartikel (refereegranskat)abstract
- By a combination of surface-sensitive photoelectron spectroscopy and molecular dynamics simulations, we characterize the surface propensity of the iodide anion in aqueous solutions at acidic, neutral, and basic conditions (pH = 1, 6.8 and 13). In both experiments and simulations, an increased surface concentration of I- is found in non-neutral solutions. We interpret these findings in terms of I- surface coadsorption with hydronium at low pH and "salting out" of iodide by hydroxide from the bulk solution to the surface at high pH. The present study is thus in accord with the picture of a weak surface adsorption of hydronium and surface depletion of hydroxide, being in sharp contradiction with the interpretation of electrophoretic and titration measurements in terms of strong surface enrichment of OH-.
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| 10. |
- Ottosson, Niklas, et al.
(författare)
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Molecular Sinkers : X-ray Photoemission and Atomistic Simulations of Benzoic Acid and Benzoate at the Aqueous Solution/Vapor Interface
- 2012
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Ingår i: Journal of Physical Chemistry B. - : American Chemical Society (ACS). - 1520-6106 .- 1520-5207. ; 116:43, s. 13017-13023
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Tidskriftsartikel (refereegranskat)abstract
- In this work we, for the first time, provide a detailed microscopic picture of the behavior of benzoic acid at the aqueous solution/vapor interface in its neutral as well as in its dissociated form (benzoate). This is achieved through a combination of highly surface-sensitive X-ray photoelectron spectroscopy experiments and fully atomistic molecular simulations. We show that drastic changes occur in the interface behavior of the neutral acid upon release of the proton. The benzoic acid molecules are found to be strongly adsorbed in the interface layer with the planes of the aromatic rings oriented almost parallel to the water surface. In contrast, in the benzoate form the carboxylate group shows a sinker-like behavior while the aromatic ring acts as a buoy, oriented nearly perpendicular to the surface. Furthermore, a significant fraction of the molecular ions move from the interface layer into the bulk of the solution. We rationalize these findings in terms of the very different hydration properties of benzoic acid's carboxylic group in the two charge states. The molecule has an amphiphilic nature and the deprotonation thus changes the hydrophobic/hydrophilic balance between the nonpolar aromatic and the polar carboxylic parts of the molecule. That, consequently, leads to a pronounced reorientation of the molecule at the interface.
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