| 1. |
- Forslund, Ola Kenji, et al.
(författare)
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Magnetic phase diagram of K 2 Cr 8 O 16 clarified by high-pressure muon spin spectroscopy
- 2019
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Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 9:1
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Tidskriftsartikel (refereegranskat)abstract
- The K 2 Cr 8 O 16 compound belongs to a series of quasi-1D compounds with intriguing magnetic properties that are stabilized through a high-pressure synthesis technique. In this study, a muon spin rotation, relaxation and resonance (μ + SR) technique is used to investigate the pressure dependent magnetic properties up to 25 kbar. μ + SR allows for measurements in true zero applied field and hereby access the true intrinsic material properties. As a result, a refined temperature/pressure phase diagram is presented revealing a novel low temperature/high pressure (p C1 = 21 kbar) transition from a ferromagnetic insulating to a high-pressure antiferromagnetic insulator. Finally, the current study also indicates the possible presence of a quantum critical point at p C2 ~ 33 kbar where the magnetic order in K 2 Cr 8 O 16 is expected to be fully suppressed even at T = 0 K.
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| 2. |
- Molander, Olof, et al.
(författare)
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Development of the Gambling Disorder Identification Test (G-DIT) : Protocol for a Delphi Method Study
- 2019
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Ingår i: JMIR Research Protocols. - : JMIR Publications Inc.. - 1929-0748. ; 8:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Research on the identification and treatment of problem gambling has been characterized by a wide range of outcome measures and instruments. However, a single instrument measuring gambling behavior, severity, and specific deleterious effects is lacking. Objective: This protocol describes the development of the Gambling Disorder Identification Test (G-DIT), which is a 9-to 12-item multiple-choice scale with three domains: gambling consumption, symptom severity, and negative consequences. The scale is analogous to the widely used Alcohol Use Disorders Identification Test (AUDIT) and the Drug Use Disorders Identification Test (DUDIT). Methods: The G-DIT is developed in four steps: (1) identification of items eligible for the G-DIT from a pool of existing gambling measures; (2) presentation of items proposed for evaluation by invited expert researchers through an online Delphi process and subsequent consensus meetings; (3) pilot testing of a draft of the 9- to 12-item version in a small group of participants with problem gambling behavior (n= 12); and (4) evaluation of the psychometric properties of the final G-DIT measure in relation to the existing instruments and self-reported criteria of the Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-5), among individuals with problem gambling and nonproblematic recreational gambling behaviors (n= 600). This protocol article summarizes step 1 and describes steps 2 and 3 in detail. Results: As of October 2018, steps 1-3 are complete, and step 4 is underway. Conclusions: Implementation of this online Delphi study early in the psychometric development process will contribute to the face and construct validity of the G-DIT. We believe the G-DIT will be useful as a standard outcome measure in the field of problem gambling research and serve as a problem-identification tool in clinical settings.
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| 3. |
- Månsson, Viktor
(författare)
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Haemophilus influenzae – typing, epidemiology and beta-lactam resistance
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Haemophilus influenzae is a common cause of respiratory tract infections such as acute otitis media (AOM), exacerbations of chronic obstructive pulmonary disease (COPD) and pneumonia. The species is subdivided into encapsulated and non-encapsulated strains, designated type a-f and nontypeable H. influenzae (NTHi), respectively. Prior to introduction of polysaccharide-protein conjugate vaccines against H. influenzae type b (Hib) in childhood vaccination programmes this serotype frequently caused severe invasive infections in small children. Nowadays invasive disease by Hib is rare, but cases still occur. At present, NTHi is the dominating type to cause invasive disease and invasive NTHi disease appears to be increasing. Nontypeable H. influenzae disease severity traditionally has been considered largely host dependant. In parallel, non-beta-lactamase mediated beta-lactam resistance among NTHi is also increasing. In the first two studies of this thesis, we investigated capsule typing of H. influenzae by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), a technology routinely used for bacterial species identification. Mass spectra of the different types of encapsulated H. influenzae were highly similar within each type and separable from each other. The differences in mass spectra relied on the clonal population structure of encapsulated H. influenzae, with conserved type specific genetic lineages. Mass spectra of NTHi were diverse, due to their genetic heterogeneity. Following construction of a comprehensive reference database, MALDI-TOF MS showed high accuracy for capsule typing of H. influenzae. In the third study of the thesis, a clonal group of NTHi with resistance against beta-lactam antibiotics was investigated. The clonal group accounted for one quarter of clinical respiratory H. influenzae isolates with non-beta-lactamase mediated beta-lactam resistance in the study region. Furthermore, patients infected by isolates of the clonal group had an increased risk of hospitalization compared to patients infected by other NTHi, indicating enhanced virulence traits. The clonal group was also found among invasive isolates. In the final study of the thesis we retrospectively compared benzylpenicillin, whose effect on H. influenzae is debated, to wide spectrum beta-lactams (WSBLs) as empirical treatment of H. influenzae lower respiratory tract infections in patients requiring hospitalization. Empirical treatment with benzylpenicllin was not associated with higher mortality or increased risk of hospital readmission compared to treatment with WSBLs. The early clinical response rate was, however, lower for patients receiving benzylpenicillin, which was attributed mainly to a lower response rate in patients infected with beta-lactamase producing isolates. In conclusion this thesis shows that MALDI-TOF MS can be efficiently used for rapid capsule typing of H. influenzae. The newly developed method can be valuable for typing of invasive H. influenzae isolates and for surveillance of Hib vaccination efficacy. The studied clonal group appears to harbour enhanced virulence traits. This indicates that bacterial factors may affect NTHi disease severity more than previously considered, and possibly contribute to the increased incidence of invasive NTHi disease. Finally, although the effect of benzylpenicillin on H. influenzae is debated, empirical treatment of lower respiratory tract infections of mild to moderate severity caused by H. influenzae with the agent appears safe
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