1. |
- Adrian, Gabriel, et al.
(författare)
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Circulating tumour HPV16 DNA quantification – A prognostic tool for progression-free survival in patients with HPV-related oropharyngeal carcinoma receiving curative chemoradiotherapy
- 2023
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Ingår i: Radiotherapy and Oncology. - 0167-8140. ; 186
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Tidskriftsartikel (refereegranskat)abstract
- Background and Purpose: Circulating tumour (ct) human papillomavirus (HPV) DNA is detectable in HPV-related oropharyngeal carcinoma (OPSCC) patients and has the potential to become an important clinical tool. This study aimed to evaluate the prognostic significance of ctHPV16-DNA kinetics during treatment with chemoradiotherapy in HPV-related OPSCC. Patients with p16-positive OPSCC recruited to the ARTSCAN III trial, comparing radiotherapy plus cisplatin with radiotherapy plus cetuximab, constituted the study cohort. Materials and methods: Blood samples before start and at the end of treatment of 136 patients were analysed. ctHPV16-DNA was quantified by real-time (q)PCR. The correlation between ctHPV16-DNA levels and tumour burden was investigated with Pearson regression analysis. The prognostic value of ctHPV16-DNA levels at baseline and decline during treatment was evaluated by area-under-the-curve (AUC) calculations and analysed with univariable and multivariable Cox proportional hazards models. Results: ctHPV16-DNA was detectable with qPCR in 108/136 patients before start of treatment and cleared in 74% of these patients at the end of treatment. Disease burden was significantly correlated with baseline ctHPV16-DNA levels (R = 0.39, p=<0.001). Both lower baseline levels and AUC-ctHPV16DNA were associated with improved progression-free survival (p = 0.01 and p < 0.001), overall survival (p = 0.013 and p = 0.002), but not local tumour control (p = 0.12 and p = 0.2, respectively), with a stronger association for AUC-ctHPV16DNA (likelihood ratio test 10.5 vs 6.5 in Cox regression analyses of progression-free survival). In multivariable analysis including tumour volume (GTV-T) and treatment allocation (cisplatin vs cetuximab), AUC-ctHPV16DNA remained a significant prognostic marker of progression-free survival. Conclusion: ctHPV16-DNA is an independent prognostic factor in HPV-related OPSCC.
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2. |
- Arroyo Mühr, Laila Sara, et al.
(författare)
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Improving human papillomavirus (HPV) testing in the cervical cancer elimination era : The 2021 HPV LabNet international proficiency study
- 2022
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Ingår i: Journal of Clinical Virology. - : Elsevier BV. - 1386-6532. ; 154, s. 105237-
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Tidskriftsartikel (refereegranskat)abstract
- Background: Proficient Human Papillomavirus (HPV) genotyping services are essential to support HPV and cervical cancer elimination strategies, in particular to support HPV vaccine research. Objectives: To perform a global HPV genotyping proficiency study, with evaluation in relation to previous proficiency studies. Study design: The proficiency panel contained 44 coded samples (40 samples containing one or more purified HPV types (HPV6/11/16/18/31/33/35/39/45/51/52/56/58/59/68a/68b) in human DNA, 1 human DNA control and 3 DNA extraction controls). Proficiency required detection of both single and multiple infections of 50 International Units of HPV 16/18, of 500 genome equivalents for other HPV types and no false positivity. Results: One hundred and thirty-two laboratories submitted 211 datasets. Most assays used (182/211 datasets) were commercially available. An all-time high of 75% of the datasets were 100% proficient. One or more false positives were found in 17.5% of datasets. Among laboratories who participated in the 2019 proficiency study, full proficiency increased from 25% in 2019 to 60% in 2021. The high overall proficiency was mostly attributable to a large number of new laboratories, which used similar assays. Conclusions: The worldwide deterioration in comparability and reliability of HPV testing found in 2019 is now reversed and an overall increase in proficiency is found.
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3. |
- Asciutto, Katrin Christine, et al.
(författare)
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14-type HPV mRNA test in triage of HPV DNA-positive postmenopausal women with normal cytology
- 2020
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Ingår i: BMC Cancer. - : Springer Science and Business Media LLC. - 1471-2407. ; 20:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: During 2013 and 2016 the region of Skåne, Sweden started to analyse human papillomavirus (HPV) and cytology in postmenopausal women 60–65 years of age. Our aim was to evaluate high-risk (HR) HPV mRNA testing for the triage of HPV DNA-positive postmenopausal women with normal cytology. Methods: A total of 271 women, 60–65 years of age, underwent liquid-based cytology (LBC) and HPV testing by using the HR-HPV DNA MGP-PCR-Luminex assay. HR-HPV DNA-positive women with normal cytology underwent complimentary HPV mRNA testing (Aptima, Hologic Inc.). Over a period of 49 months (SD 11.0) the women received regular follow-ups at intervals of 12–18 months. Women with abnormal cytology and/or a positive HR-HPV DNA and/or mRNA result at two subsequent visits were scheduled for colposcopy and clinical examination. Results: Over the surveillance period, 3.6% (10/271) of the HR-HPV DNA-positive women developed histologically confirmed high-grade squamous intraepithelial lesions (HSILs) or worse. The cumulative incidence rates (CIR) were 29.7% (CI 24.8–30.1) for HSIL or worse among HPV mRNA-positive women at enrolment (39.5% 107/271) and 0% among HPV mRNA-negative women (60.5%, 164/271), (p = 0.002). Conclusions: Postmenopausal women with normal cytology testing positive for HR-HPV mRNA are at increased risk for the development of high-grade cervical intraepithelial neoplasia (CIN), in contrast to women with a negative HR-HPV mRNA outcome. The HR-HPV mRNA APTIMA assay detecting 14 HR-HPV types may be a useful triage method among HPV DNA-positive postmenopausal women with normal cytology.
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4. |
- Benedek, Peter, et al.
(författare)
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Quantifying Diffusion through Interfaces of Lithium-Ion Battery Active Materials
- 2020
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Ingår i: ACS Applied Materials & Interfaces. - : American Chemical Society (ACS). - 1944-8252 .- 1944-8244. ; 12:14, s. 16243-16249
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Tidskriftsartikel (refereegranskat)abstract
- Detailed understanding of charge diffusion processes in a lithium-ion battery is crucial to enable its systematic improvement. Experimental investigation of diffusion at the interface between active particles and the electrolyte is challenging but warrants investigation as it can introduce resistances that, for example, limit the charge and discharge rates. Here, we show an approach to study diffusion at interfaces using muon spin spectroscopy. By performing measurements on LiFePO4 platelets with different sizes, we determine how diffusion through the LiFePO4 (010) interface differs from that in the center of the particle (i.e., bulk diffusion). We perform ab initio calculations to aid the understanding of the results and show the relevance of our interfacial diffusion measurement to electrochemical performance through cyclic voltammetry measurements. These results indicate that surface engineering can be used to improve the performance of lithium-ion batteries.
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5. |
- Borgfeldt, Christer, et al.
(författare)
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Co-testing in cervical screening among 40- to 42-year-old women is unreasonable
- 2022
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Ingår i: Acta Obstetricia et Gynecologica Scandinavica. - : Wiley. - 0001-6349 .- 1600-0412. ; 101:3, s. 374-378
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: The screening program for cervical cancer in Sweden recommends the use of primary human papillomavirus (HPV) screening for women aged ≥30 to 65 years. Co-testing with both HPV analysis and cytology is recommended at the first screening after the age of 40 years. To fulfil co-testing, all screened women aged 40–42 years within the region of Skåne were co-tested. The aim of the audit was to investigate the proportion of severe dysplasia as diagnosed by cytology and histological follow-up among women with Aptima HPV-negative tests. We also calculated the cost of adding the cytology to the HPV primary screening program. Material and Methods: The local cytology registry was used to identify women aged 40–42 years who attended screening and were co-tested during the 4 years from January 2017 to December 2020. The Aptima HPV messenger RNA assay detects 14 HPV types. For Aptima HPV-negative women with high-grade cytology or histological high-grade squamous intraepithelial lesions (HSILs), we performed extended HPV typing for 40 HPV types with polymerase chain reaction using modified GP5+/6+ primers followed by a Luminex assay. To estimate the added cost of using cytology to identify each histologically confirmed cervical HSIL case among Aptima HPV-negative women, we used the current cost of €21.2 per cytology evaluation at our laboratory. Results: Of 19 599 women, 5.8% (1137/19 599) had abnormal cytology. Among Aptima HPV-negative women, 0.11‰ (2/18 132) had histologically confirmed HSIL. One of the women was infected with HPV18 and the other with HPV73 at the diagnosis of HSIL. The calculated cost to find one HSIL, by adding cytology to HPV-negative cases, was approximately €200 000. Conclusions: The clinical benefit of a single cytology co-test added to an HPV-based screening program in women aged 40–42 years appears doubtful and economically unreasonable.
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6. |
- Borgfeldt, Christer, et al.
(författare)
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HPV73 in cervical cancer and distribution of HPV73 variants in cervical dysplasia
- 2021
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Ingår i: International Journal of Cancer. - : Wiley. - 0020-7136 .- 1097-0215. ; 149:4, s. 936-943
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Tidskriftsartikel (refereegranskat)abstract
- HPV73 is classified as possibly oncogenic and is not recognized by most commercial primary HPV screening platforms. The aim was to determine the prevalence of HPV73 among invasive cervical cancers, formalin-fixed paraffin embedded (FFPE) samples (N = 69), from southern Sweden during 2009 to 2010. Another aim was to determine proportions of HPV73 among Aptima HPV assay negative cervical cancers (N = 9, out of 206 cancers) and of high-grade cytological cervical diagnosis (N = 75, out of 5807 high grade lesions) in liquid-based cytology (LBC) samples collected between 2016 and 2019. We also investigated the distribution of HPV73 variants A1, A2 and B among HPV73-positive cases. HPV73 was detected by multiplex MGP-PCR and Luminex, and HPV73 variants were identified by sequencing PCR amplicons. HPV73 was detected in 2.9% (2/69, 95% CI: 0.18-9.9) of the FFPE cervical cancer series. Among the Aptima HPV-negative LBC samples, HPV73 was present in 55.5% (5/9) of the cancers and 29.3% (22/75) of the different grades of cervical diagnosis. The A1, A2 and B variants were present in 6.9% (2/29), 82.7% (24/29) and 10.3% (3/29) of the HPV73-positive women, respectively. Among the seven HPV73 cancer cases (two FFPE samples and five LBC samples), six A2 and one A1 isolate were detected. In summary, the A2 variant of HPV73 was most common in our region. In addition, the observed prevalence of HPV73 (2.9%) in cervical cancers and its relative high occurrence (55.5%) among Aptima HPV-negative cancers urge that detection of HPV73 should be included in future primary HPV screening programs.
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7. |
- Brett, Calvin, et al.
(författare)
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Humidity-Induced Nanoscale Restructuring in PEDOT:PSS and Cellulose Nanofibrils Reinforced Biobased Organic Electronics
- 2021
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Ingår i: Advanced Electronic Materials. - : Wiley. - 2199-160X. ; 7:6, s. 2100137-
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Tidskriftsartikel (refereegranskat)abstract
- In times where research focuses on the use of organic polymers as a base for complex organic electronic applications and improving device efficiencies, degradation is still less intensively addressed in fundamental studies. Hence, advanced neutron scattering methods are applied to investigate a model system for organic electronics composed of the widely used conductive polymer blend poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) together with nanocellulose as flexible reinforcing template material. In particular, the impact of relative humidity (RH) on the nanostructure evolution is studied in detail. The implications are discussed from a device performance point of view and the changing nanostructure is correlated with macroscale physical properties such as conductivity. The first humidification (95% RH) leads to an irreversible decrease of conductivity. After the first humidification cycle, however, the conductivity can be reversibly regained when returning to low humidity values (5% RH), which is important for device manufacturing. This finding can directly contribute to an improved usability of emerging organic electronics in daily live.
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8. |
- Eklund, Carina, et al.
(författare)
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The 2019 HPV Labnet international proficiency study : Need of global Human Papillomavirus Proficiency Testing
- 2021
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Ingår i: Journal of Clinical Virology. - : Elsevier BV. - 1386-6532. ; 141, s. 104902-
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Tidskriftsartikel (refereegranskat)abstract
- Background:: Accurate and internationally comparable human papillomavirus (HPV) testing services are essential for cervical cancer elimination programs. The WHO HPV Laboratory Network started issuing international HPV testing proficiency panels in 2008. Objectives:: We report the results of the 2019 global proficiency study and evaluate the proficiency over time. Study design:: The proficiency panel contained 40 coded samples containing mixes of purified HPV types (HPV6/11/16/18/31/33/35/39/45/51/52/56/58/59/68a/68b) and 4 controls. Proficiency required detection of both single and multiple infections of 50 International Units of HPV 16/18, of 500 genome equivalents (10x higher concentration) for other HPV types, and no false positives (stricter requirement compared to previous panels). Results:: Seventy-eight laboratories submitted 110 datasets with 38 different assays. Most samples (38/44) were reported with 100% proficiency in most datasets. Mostly commercial assays were used (88/110 datasets). Overall, 47.3% of the datasets were 100% proficient. False positivity was detected in at least one sample in 30.1% of datasets. When analysing all datasets ever since 2008 using exactly the same proficiency criteria, there was a steady improvement up to 2017 (the proportion of datasets being completely proficient increased from 25% to 73%). However, in the 2019 proficiency testing the proportion of fully proficient datasets dropped to 50%. Conclusions:: Although we initially documented a worldwide improvement in comparability and reliability of HPV testing services, the trend now appears to be reversed. In response, the International HPV Reference Center will provide support for improved quality of laboratory services, including issuing of global proficiency panels every year.
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9. |
- Elson, Frank, et al.
(författare)
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TRIM Simulations Tool for μ + Stopping Fraction in Hydrostatic Pressure Cells
- 2023
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Ingår i: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 2462:1
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Konferensbidrag (refereegranskat)abstract
- For quantum systems or materials, a common procedure for probing their behaviour is to tune electronic/magnetic properties using external parameters, e.g. temperature, magnetic field or pressure. Pressure application as an external stimuli is a widely used tool, where the sample in question is inserted into a pressure cell providing a hydrostatic pressure condition. Such device causes some practical problems when using in Muon Spin Rotation/Relaxation (μ +SR) experiments as a large proportion of the muons will be implanted in the pressure cell rather than in the sample, resulting in a higher background signal. This issue gets further amplified when the temperature dependent response from the sample is much smaller than that of the pressure cell,which may cause the sample response to be lost in the background and cause difficulties in aligning the sample within the beam. To tackle this issue, we have used pySRIM [1] to construct a practical and helpful simulation tool for calculating muon stopping fractions, specifically for the pressure cell setup at the μE1 beamline using the GPD spectrometer at the Paul Scherrer Institute, with the use of TRIM simulations. The program is used to estimate the number of muon stopping in both the sample and the pressure cell at a given momentum. The simultion tool is programmed into a GUI, making it accessible to user to approximate prior to their experiments at GPD what fractions will belong to the sample and the pressure cell in their fitting procedure.
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10. |
- Ernstson, Avalon, et al.
(författare)
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Cervical cancer prevention among long-term screening non-attendees by vaginal self-collected samples for hr-HPV mRNA detection
- 2020
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Ingår i: Infectious Agents and Cancer. - : Springer Science and Business Media LLC. - 1750-9378. ; 15:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: The efficacy of cervical cancer screening programs is dependent on the participation rate. To increase participation among women not attending cervical cancer screening, self-collected samples for detection of high-risk human papillomavirus (hr-HPV) may be an option. The aims of this study were: to investigate the response rate to sending a self-collected vaginal sample for hr-HPV mRNA detection to long-term non-attendees; the compliance with follow-up among women positive for HPV in the self-sample; the prevalence of cervical dysplasia (high grade squamous intraepithelial lesion (HSIL), atypical squamous cells that cannot exclude HSIL (ASC-H) or adenocarcinoma in situ (AIS)) or cancer among the responders; as well as to explore reasons for not returning a self-sample. Methods: A vaginal self-sampling kit was sent to 6023 women aged 30-70 years who had not provided a cervical screening sample for ≥7 years in the Region of Skåne, Sweden in November and December 2017. The self-sample was analyzed by Aptima HPV mRNA assay (Hologic). All vaginal self-samples returned no later than May 31, 2018 were included in the study. Follow-up of the results was registered until January 31, 2019 with a follow-up time varying between eight to 14 months. Women positive for hr-HPV mRNA were invited for a follow-up examination. This examination consisted of a cervical sample for cytological analysis and renewed Aptima HPV mRNA testing. Two hundred thirty-five women who had not returned the self-sample were randomly selected for telephone interviews, in order to explore their reasons. Results: The response rate for the self-collected vaginal hr-HPV sample was 13.2% [(797/6023), 95% CI 12.4-14.1%] and 9.9% [(79/796), 95% CI 7.9-12.2%] were positive for hr-HPV mRNA. The prevalence of severe dysplasia or cancer in the whole group of responders was 1.3% [(10/796), 95% CI 0.6-2.3%], with a cervical cancer prevalence of 0.4% [(3/796), 95% CI 0.1-1.1%]. Only 27 women participated in the telephone interviews, no particular reason for not returning self-samples was observed. Conclusions: Self-collected vaginal hr-HPV samples increased participation in the cervical cancer screening among long-term non-attendees. The prevalence of cervical cancer was almost seven times higher for long-term non-attendees than in the organized screening population.
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11. |
- Ernstson, Avalon, et al.
(författare)
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Promotion of Cervical Screening among Long-term Non-attendees by Human Papillomavirus Self-sampling
- 2021
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Ingår i: Journal of Cancer Prevention. - 2288-3649. ; 26:1, s. 25-31
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Tidskriftsartikel (refereegranskat)abstract
- Cervical cancer is preventable through gynecological screening. To promote participation among non-attending women, self-collected vaginal samples for detection of high-risk human papillomavirus (hr-HPV) is an option. The aims of this study were to investigate the response of self-collected vaginal samples for hr-HPV testing among long-term non-attendees, to explore the attendance at follow-up among HPV-positive women, and to analyze the prevalence of hr-HPV and severe cervical dysplasia or cancer among the responders. A vaginal self-sampling kit was sent to 19,766 women aged 30-70 years who had not provided a cervical screening sample for ≥ 7 years in Skåne, Sweden. The self-sample was analyzed by the Aptima HPV mRNA assay (Hologic). Women testing positive for HPV were invited for follow-up. The response was 18.5% (3,646/19,757). The prevalence of HPV mRNA was 11.3% (412/3,636). Among HPV-positive women, 85.7% (353/412) attended follow-up, and of these, 44.8% (158/353) had HPV in the cervical sample. The HPV mRNA test of self-samples showed a positive predictive value of 9.3% ([33/353], 95% CI = 6.5-12.9) for detection of cytologically severe dysplasia. Histologically severe dysplasia or cancer was detected in 0.88% ([32/3,636], 95% CI = 0.6-1.2) among responders, including two cervical- and one vaginal cancer. In conclusion, almost one fifth of the long-term non-attendees participated in self-collected vaginal hr-HPV sampling. The prevalence of histologically confirmed high grade squamous intraepithelial lesion or cervical cancer was not increased significantly compared to regularly screened women in Sweden. The relatively high HPV prevalence among the self-samples indicates the importance of diagnostic follow-up with cervical HPV testing and reflex-cytology of HPV-positive cases.
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12. |
- Forslund, Maria, 1982-
(författare)
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From the cradle to the grave - in sickness and in health? : The welfare state and health outcomes
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Sickness, whether manifested through actual sickness or through fear of sickness, is a part of human life. Sickness cash benefits was one of the earliest social security programs implemented in modern welfare states. Previous research on how sickness benefits are associated with health outcomes has emphasized the significance of income. Sickness is a social risk in terms of income loss, and sickness benefits has the potential to compensate such losses. Just as cash benefits are an essential part of the welfare state, so are public services. Public services, and healthcare in particular, are crucial for health outcomes. Yet, comparative research on healthcare is just beginning to take off in research. This thesis extends previous research in two ways. First, the thesis considers the impact of sickness cash benefits and healthcare for health outcomes, as well as the interplay between cash and care. Secondly, the thesis applies a life course perspective aligning comparative welfare state research and cumulative dis/advantage theory. The thesis thereby contributes with new knowledge, empirically as well as theoretically, which together provides a comprehensive assessment of important links between the welfare state and population health. Study I examines the relationship between sickness benefits and life expectancy at age 65 in 15 OECD countries, 1960–2015. The study is novel as it applies a life course perspective on sickness benefits, combining cumulative dis/advantage theory and a comparative welfare state approach. It adds to previous research by focusing on the cumulative access cohorts have had to sickness benefits during their time active in the labour market. The results support previous research showing that universal coverage of sickness benefits appears to be associated with lower mortality. Study II analyses the relationship between primary care and inequalities in self-rated health based on educational attainment in 24 countries 2002–2018. Previous research has pointed to an increasing educational gradient in health over the last decades. Primary care has been argued to be especially important when aiming to reduce such health inequalities. The results show that in countries where primary care is of higher quality, the educational gradient in self-rated health is lower. Study III analyses the interplay between healthcare resources and sickness benefits in relation to premature mortality in a sample of 14 countries for the time period 1980–2011. The study lends support to there being an interaction effect between healthcare and sickness benefits. Although healthcare and sickness benefits are two different aspects of the welfare state, future research should consider the interplay between cash and care. Taken together, the thesis demonstrates the importance of considering how different aspects of the welfare state and separate policy programmes works in conjunction. The thesis further emphasizes the importance of using a life course approach in analysing health outcomes of the welfare state and social policy.
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13. |
- Forslund, Ola Kenji
(författare)
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1D to 3D Magnetism in Quantum Materials: A study by Muons, Neutrons & X-rays
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- A collection of works stretching from low- to three-dimensional magnetism are presented, studied mostly through muon spin rotation, relaxation and resonance (µ +SR). The theoretical background of this technique is outlined in Chapter 2, which introduces the subject from the muon particle as an astro[1]nomical particle to how they are produced here on Earth. Given the specific properties of weak particle interactions, previous generations of scientists developed the technique of µ +SR. Special care is taken to explain how the anti-muon interacts with magnetic fields and the resulting behaviour of the anti-muon in a given magnetic field configuration. The fundamental principle of µ +SR is to interpret the resulting muon behaviour in order to unveil microscopic details of the compounds of interest. Other experimental techniques were utilised to confirm the assessment made by µ +SR and to probe different aspects of the compounds being studied. Specifically, neutron and X-ray scattering were performed; the corresponding theoretical background is presented in Chapter 4. Interpretations, conclusions and discussions regarding the studied compounds are presented in Chapter 5. This chapter is divided into four parts depending on the study: one-dimensional (1D), two-dimensional (2D) and three-dimensional (3D) magnets and studies related to µ +SR in general. The 1D compounds comprise mostly samples within the Hollandite family, which exhibit quasi-1D chains of transition metal ions. These chains may in certain cases facilitate interactions in a 1D fashion, which is a very interesting feature. In particular, a quantum spin liquid phase is found in one of the compounds, stabilised by a peculiar form of charge ordering occurring at high temperature. Microscopic evidence for the absence of a Peierls transition in a ferromagnetic metal-insulator transition compound is presented as well. The 2D compounds include layer-structured samples in which intralayer interactions are assumed to be dominant. Interestingly, the ground state was found to not be governed only by the intralayer interactions, at least in one of the compounds. Instead, the charge distribution in between the layers seems to have a role to play, as the specific cation ordering determined the ground state. A study in which this distribution is changed to study its effect on the ground state is presented. The 3D magnets considered here exhibit unique interactions available in these compounds. Complicated phases emerge above the transition temperature due to modulation of interactions in space. Finally, a collection of interesting studies related to general µ +SR are included in Chapter 5. These include a study of lithium ion diffusion anisotropy detected for the first time by µ +SR and a semantical discussion related to the term muonium. Other studies not related to this thesis are listed in Articles not included in this thesis. This thesis concludes with Chapter 6, which briefly summarises the work and the resulting outcomes. Most importantly, a smaller discussion on the future of physics is presented, considering its implications for society and science as a whole.
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14. |
- Forslund, Ola Kenji, et al.
(författare)
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Co-existence of short- and long-range magnetic order in LaCo2P2
- 2021
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Ingår i: Physica Scripta. - : IOP Publishing. - 0031-8949 .- 1402-4896. ; 96:12, s. 125864-
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Tidskriftsartikel (refereegranskat)abstract
- The ferromagnetic (FM) nature of the metallic LaCo2P2 was investigated with the positive muon spin rotation, relaxation and resonance (μ+SR) technique. Transverse and zero field μ+ SR measurements revealed that the compound enters a long range FM ground state at K, consistent with previous studies. Based on the reported FM structure, the internal magnetic field was computed at the muon sites, which were predicted with first principles calculations. The computed result agree well with the experimental data. Moreover, although LaCo2P2 is a paramagnet at higher temperatures T > 160 K, it enters a short range ordered (SRO) magnetic phase for K. Measurements below the vicinity of revealed that the SRO phase co-exists with the long range FM order at temperatures 124 K . Such co-existence is an intrinsic property and may be explained by an interplay between spin and lattice degree of freedoms.
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15. |
- Forslund, Ola Kenji, et al.
(författare)
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Intertwined magnetic sublattices in the double perovskite compound LaSrNiReO6
- 2020
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Ingår i: Physical Review B. - : American Physical Society. - 2469-9969 .- 2469-9950. ; 102:14
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Tidskriftsartikel (refereegranskat)abstract
- We report a muon spin rotation (μ+SR) study of the magnetic properties of the double perovskite compound LaSrNiReO6. Using the unique length and time scales of the μ+SR technique, we successfully clarify the magnetic ground state of LaSrNiReO6, which was previously deemed as a spin glass state. Instead, our μ+SR results point toward a long-range dynamically ordered ground state below TC=23 K, for which a static limit is foreseen at T=0. Furthermore, between 23K250 K) state. Our results reveal how two separate yet intertwined magnetic lattices interact within the unique double perovskite structure and the importance of using complementary experimental techniques to obtain a complete understanding of the microscopic magnetic properties of complex materials.
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16. |
- Forslund, Ola Kenji, 1990, et al.
(författare)
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Pressure driven magnetic order in Sr 1 - x Ca x Co 2 P 2
- 2022
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322 .- 2045-2322. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- The magnetic phase diagram of Sr1-xCaxCo2P2 as a function of hydrostatic pressure and temperature is investigated by means of high pressure muon spin rotation, relaxation and resonance (μ+SR). The weak pressure dependence for the x≠ 1 compounds suggests that the rich phase diagram of Sr1-xCaxCo2P2 as a function of x at ambient pressure may not solely be attributed to chemical pressure effects. The x= 1 compound on the other hand reveals a high pressure dependence, where the long range magnetic order is fully suppressed at pc 2≈ 9.8 kbar, which seem to be a first order transition. In addition, an intermediate phase consisting of magnetic domains is formed above pc 1≈ 8 kbar where they co-exist with a magnetically disordered state. These domains are likely to be ferromagnetic islands (FMI) and consist of an high- (FMI-1) and low-temperature (FMI-2) region, respectively, separated by a phase boundary at Ti≈ 20 K. This kind of co-existence is unusual and is originating from a coupling between lattice and magnetic degrees of freedoms.
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17. |
- Forslund, Ola Kenji, et al.
(författare)
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Pressure driven magnetic order in Sr1-xCaxCo2P2
- 2022
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Ingår i: Scientific Reports. - : Springer Nature. - 2045-2322. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- The magnetic phase diagram of Sr1-xCaxCo2P2 as a function of hydrostatic pressure and temperature is investigated by means of high pressure muon spin rotation, relaxation and resonance (mu+SR). The weak pressure dependence for the x not equal 1- compounds suggests that the rich phase diagram of Sr1-xCaxCo2P2 as a function of x at ambient pressure may not solely be attributed to chemical pressure effects. The x = 1 compound on the other hand reveals a high pressure dependence, where the long range magnetic order is fully suppressed at p(c2) approximate to 9.8 kbar, which seem to be a first order transition. In addition, an intermediate phase consisting of magnetic domains is formed above p(c1) approximate to 8 kbar where they co-exist with a magnetically disordered state. These domains are likely to be ferromagnetic islands (FMI) and consist of an high- (FMI-(1)) and low-temperature (FMI-(2)) region, respectively, separated by a phase boundary at T-i approximate to 20 K. This kind of co-existence is unusual and is originating from a coupling between lattice and magnetic degrees of freedoms.
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18. |
- Forslund, Ola Kenji, et al.
(författare)
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Revisiting the A-type antiferromagnet NaNiO2 with muon spin rotation measurements and density functional theory calculations
- 2020
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Ingår i: Physical Review B. - : American Physical Society. - 2469-9950 .- 2469-9969. ; 102:18
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Tidskriftsartikel (refereegranskat)abstract
- An A-type antiferromagnet, NaNiO2, was examined by means of positive muon spin rotation and relaxation (mu+SR) measurements and first-principles calculations based on a density functional theory (DFT). Below T-N = 20 K, a clear muon spin precession signal was observed in the mu+SR time spectrum recorded under zero field, due to the formation of a static internal magnetic field. The microscopic origin of such an internal field was computed as a sum of dipolar and hyperfine contact fields at the site (0.624, 0, 0.854), where both the muon site and the local spin density at such a site were predicted with DFT calculations. While the computed values were consistent with experimentally obtained ones, in both the antiferromagnetic and the paramagnetic states, the contribution of the hyperfine contact field was shown to be insignificant even below T-N. Finally, measurements at higher temperatures signified thermally activated Na-ion diffusion with E-a = 50(20) meV and D-Na(300K) = 8.8 x 10(-11) cm(2)/s, commonly observed in layered-type compounds.
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19. |
- Ge, Yuqing, 1996, et al.
(författare)
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Confirming the high pressure phase diagram of the Shastry-Sutherland model
- 2023
-
Ingår i: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 2462:1
-
Konferensbidrag (refereegranskat)abstract
- A Muon Spin Rotation (μ + SR) study was conducted to investigate the magnetic properties of SrCu2(BO3)2 (SCBO) as a function of temperature/pressure. Measurements in zero field and transverse field confirm the absence of long range magnetic order at high pressures and low temperatures. These measurements suggest changes in the Cu spin fluctuations characteristics above 21 kbar, consistent with the formation of a plaquette phase as previously suggested by inelastic neutron scattering measurements. SCBO is the only known realisation of the Shatry-Sutherland model, thus the ground state mediating the dimer and antiferromagnetic phase is likekly to be a plaquette state.
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20. |
- Grönberg, Annika, 1970-
(författare)
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Predictors of long-term glycemic control, pancreatic function and BMI trajectory in children with type 1 diabetes
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: The maintenance of normal metabolic control underpins all management of insulin dependent diabetes whether in terms of preserved beta-cell function, body composition, or family support. The hypothesis of this work was that preserved C-peptide predicts better glycemic control and lowers risk of severe hypoglycemia. It was additionally investigated whether Body Mass Index (BMI) and family structure contributes to the prediction of long-term glycemic control. Objectives: This thesis aimed to 1) identify the factors associated with residual C peptide production at least 10 years after diagnosis, 2) evaluate the association of BMI trajectory and long-term glycemic control, 3) identify early characteristics associated with rapid or slow decline of beta-cell function and how it affects the clinical course, and 4) investigate the relations of family structure at diagnosis and long-term glycemic control. Methods: Data from four cohorts were used: In the Uppsala cohort, measurement of long-term residual C-peptide was undertaken using ultrasensitive C-peptide ELISA in 73 children and adolescents <25 years, BMI trajectory prior diagnosis was evaluated in 295 children, while family structure at diagnosis was evaluated in 215 children in relation to glycemic control. In the Linköping cohort, stimulated C-peptide was assessed by mixed meal tolerance test in 50 children. Results: The cohort studies showed that better early glycemic control predicted long term residual C-peptide and that long term residual C-peptide, in turn, was protective against severe hypoglycemia. Additionally, BMI trajectory was predicted by BMI prior to the presentation of type 1 diabetes. There was no association with glycemic outcome. Children living in a whole family had a lower probability of long-term dysglycemia. Conclusions: Residual C-peptide is important for better glycemic control and to reduce complications in children with type 1 diabetes. Family structure, but not BMI trajectory, contributes to the prediction of long-term glycemic control. However, more research is needed to understand how to preserve the beta-cell function in children and to target and support families in those children with early deteriorating glycemic control to reduce future complications.
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21. |
- Hellsten, Caroline, et al.
(författare)
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Cervical cancer in Region Skåne, Sweden 2017–2020 after the implementation of primary HPV screening : A quality assurance audit
- 2024
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Ingår i: Acta Obstetricia et Gynecologica Scandinavica. - 0001-6349. ; 103:1, s. 129-137
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Primary human papilloma virus (HPV) screening to detect cervical cancer and dysplastic lesions was implemented in Region Skåne 2017 for women aged 30–70. The aim of this study was to characterize the screening history of women diagnosed with cervical cancer to evaluate the performance of the screening program, as well as to assess the cancer treatments given and shortcomings in the follow-up of women with cervical dysplasia. Material and methods: We performed a quality assurance audit. The data was collected from the National Cervical Cancer Prevention Registry, Region Skåne Labmedicin database and the Melior Journal system in 2017–2020. Results: We identified 247 women diagnosed with invasive cervical cancer in Region Skåne in 2017–2020. Of these, 35 (14.2%) had a screening history over at least two screening rounds before diagnosis. There were 25 (10.1%) women diagnosed with cervical cancer in between screening intervals, i.e., interval cancer. The most common screening history in women with cervical cancer was irregular screening (143, 57.9%), followed by women being above screening age (44, 17.8%). HPV was detected in 96% of the cases, either in cervical cytology or in the tumor tissue. The screening program detected the disease in 96 (38.9%) of the patients, 149 (60.3%) were diagnosed through symptoms and two (0.80%) as a result of incidental findings. Conclusions: The most powerful tool in the prevention of cervical cancer is screening program attendance. Prolongation with HPV screening among elderly women will also reduce the incidence of cervical cancer. Today, such cancers are usually discovered when symptoms appear.
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22. |
- Hellsten, Caroline, et al.
(författare)
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Equal prevalence of severe cervical dysplasia by HPV self-sampling and by midwife-collected samples for primary HPV screening : A randomised controlled trial
- 2021
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Ingår i: European Journal of Cancer Prevention. - 0959-8278. ; 30:4, s. 334-340
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Tidskriftsartikel (refereegranskat)abstract
- Objectives HPV self-sampling is an option for cervical screening. The aim of this randomised study was to investigate the compliance, prevalence of HPV, and prevalence of severe dysplasia in a vaginal self-sampling group in comparison to cervical samples collected by midwives (control arm). The hypothesis was that there would be no difference between vaginal self-sampling and cervical sampling to find high-grade cervical dysplasia or cancer. Methods Vaginal HPV self-sampling kits were sent by regular mail to 14 765 randomly selected women aged 30-64 years old in the screening programme. HPV-positive women were invited for a follow-up examination by their midwife in which they provided a cervical sample for cytological and HPV co-testing. The control arm consisted of 14 839 women who met the same inclusion criteria and were invited to have cervical sampling by midwives for primary HPV screening. All HPV samples were analysed by the Aptima HPV assay (Hologic Inc.). Main results The participation rate was 33.5% in the self-sampling arm and 47.5% in the cervical sampling arm, (P < 0.0001). HPV was detected in 17.1% (95% confidence interval (CI), 16.1-18.23%) in the self-sampling arm and 4.5% (95% CI, 4.0-5.0%) in the cervical sampling arm. Histological, severe dysplasia was observed among 0.48% (95% CI, 0.3-0.72%) and 0.47% (95% CI, 0.3-0.66%) of the self-sampling and the cervical sampling groups, respectively. Conclusion The self-sampling approach detects a similar proportion of severe dysplasia as regular screening. Thus, our study indicates that self-sampling could replace primary HPV screening of cervical samples.
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23. |
- Jimenez, David Gomez, et al.
(författare)
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Tonsillar cancer with high cd8+ t‐cell infiltration features increased levels of dendritic cells and transcriptional regulation associated with an inflamed tumor microenvironment
- 2021
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Ingår i: Cancers. - : MDPI AG. - 2072-6694. ; 13:21
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Tidskriftsartikel (refereegranskat)abstract
- Human papillomavirus (HPV) is the main causal agent of tonsillar cancer (TC) and HPV+ TC has a favorable prognosis compared to HPV– disease. In this study, we examined aspects of the tumor microenvironment of TC, focusing on T‐cells, dendritic cells (DC), and macrophages. Fresh biopsies of TC and the contralateral healthy tonsil (HT) were obtained from 20 patients, analyzed by multiparameter flow cytometry, and assessed against a detailed HPV‐status. Additionally, RNA-sequencing data from 38 TC samples available in the public database, The Cancer Genome Atlas (TCGA), were explored, focusing on the same leukocyte populations. HPV+ TC featured increased levels of CD8+ T‐cells and antigen‐presenting cells (cf. HPV– TC and HT, respectively). In HPV+ TC, CD8+ T‐cell frequencies correlated to DC levels independently of tumor stage, HPV 16 copy number, and E7 oncogene expression as well as frequencies of other leukocytes. Similarly, RNA sequencing data were explored by dividing the HPV+ TCs according to predefined CD8+ T‐cell scores in silico. Higher levels of genes expressed by antigen‐presenting cells and effector T‐cells, such as immune checkpoints and cytokines, were detected in the CD8HIGH HPV+ TC samples (cf. CD8LOW HPV+ TC). In conclusion, CD8HIGH HPV+ TC displays a unique inflammatory profile associated with increased effector T‐cell functions and the presence of antigen‐presenting cells in the tumor microenviron-ment. Further studies are warranted to assess if this information can be used on an individual basis to aid in prognosis and treatment decisions.
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24. |
- Jönsson, Johanna, 1993-
(författare)
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The balance of splicing : A novel insight into the splicing regulation of high-risk HPV E6 and E7 oncogenes.
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- HPV is associated with several cancers. The genome consists of a long control region, early (E1, E2, E4, E5, E6 and E7) and late (L1 and L2) genes. The E6 and E7 proteins prevent cells from entering apoptosis and regulate the cell cycle. A deregulated expression of these can result in malignant transformations. Therefore, a deeper understanding of their regulation is important. HPV gene expression regulation occurs mainly through alternative pre-mRNA splicing with many splice events being mutually exclusive. This is the case with E6 and E7. E6 is expressed from the intron-retained mRNA while E7 is expressed from a spliced mRNA. In this thesis it was aimed to understand the alternative splice events of HPV16 E6 and E7 mRNAs by identifying regulatory elements controlling these splice events. A strong enhancer, downstream of SA409, was identified. It consists of a perfect bipartite repeat and mutations in the element disrupts SA409 splicing. Trans-acting factors were determined to TRAP150 and BCLAF1 (Paper I). Downstream of this is another cis-element. It consists of a GGGG-motif with a silencing effect on SA409 splicing. Two additional cis-elements, one at the end of the E6 ORF and the other at the start of the E7 ORF, were additionally found. These are suggested to hybridize forming an internal-loop structure when analyzed in silico. The cis-element at the end of the E6 ORF is context dependent, functioning as an enhancer or silencer depending on if the E7 cis-element is included or not. It was identified as ATCATCA (Paper III). The cis-element at the start of the E7 ORF was a silencer and consisted of an AUG-rich element. Two trans-acting factors interacted with it, hnRNP A1 and hnRNP A2, and prevented SA409 splicing. However, hnRNP A1 increased the intron-retained E6 mRNA, while hnRNP A2 redirected splicing to a downstream acceptor, SA742 (Paper IV). SA742 was additionally found to be regulated by another cis-element, within the E1 ORF. It consisted of three GGG/GGGG motifs and the integrity of these and of SD880 were important for SA742 usage, indicating the importance of regulatory factors in the modulation of the splicing modes: intron definition and exon definition. The trans-acting factor was hnRNP H (Paper II). In this thesis five cis-elements and five trans-acting factors affecting splicing regulation within the E6 and E7 ORFs were identified. With this knowledge to build upon several important targets to change or disrupt splicing were identified.
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25. |
- Kristiansen, Sinja, et al.
(författare)
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Incidence of penile intraepithelial neoplasia and treatment strategies in Sweden 2000–2019
- 2022
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Ingår i: BJU International. - : Wiley. - 1464-4096 .- 1464-410X. ; 129:6, s. 752-759
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: To analyse the incidence, treatment strategies and complications associated with penile intraepithelial neoplasia (PeIN) in Sweden over a period of 20 years. Materials and methods: Data on PeIN from the Swedish National Penile Cancer Register were analysed regarding treatment in relation to age, size of the PeIN lesion, localization of the PeIN lesion and complications using chi-squared tests and logistic regression. The incidence of PeIN was calculated and age-standardized according to the European Standard population. Results: Between 2000 and 2019 a total of 1113 PeIN cases were reported. The age-standardized incidence of PeIN was 1.40 per 100 000 men (95% confidence interval [CI] 1.32–1.49). An increase in incidence over time was seen, with a standardized incidence rate of 2.37 (95% CI 1.56–3.70) in 2019 compared to the baseline year, 2000. Surgical or topical treatments were given in 75.0% and 14.6% of cases, respectively. The complication rate was higher in laser surgery (12.1%, 7/58) compared to local surgery (4.6%, 16/348; P = 0.03) with an age-adjusted odds ratio (OR) of 2.82 (95% CI 1.10–7.19; P = 0.03). Local surgery was more common than laser surgery in the last 5 years compared to the first 5 years of the study period: OR 5.75 (95% CI 2.94–11.27). Treatments with imiquimod and topical 5-fluorouracil (5-FU) were more common than destructive methods such as photodynamic therapy, cryotherapy, curettage and electrocautery in the last 5 years compared to the first 5 years: OR 9.48 (95% CI 2.29–39.24). Conclusions: A twofold increase in the age-standardized incidence of PeIN was seen in Sweden over 20 years. Complications were three times more common in laser surgery compared to local surgery. Changes in treatment showed an increase of treatment strategies such as local surgery and treatment with imiquimod and topical 5-FU over time.
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26. |
- Kristiansen, Sinja, et al.
(författare)
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Increased prevalence of human papillomavirus in fresh tissue from penile cancers compared to non-malignant penile samples : a case-control study
- 2022
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Ingår i: BMC Cancer. - : Springer Science and Business Media LLC. - 1471-2407. ; 22:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: HPV has been detected in approximately 50% of invasive penile cancers but with a large span between 24 and 89%, most likely due to different types of tumors and various methods for HPV analysis. Most studies of HPV in penile cancer have been performed using paraffin-embedded tissue, argued to be at risk for contaminated HPV analysis. Viral activity of HPV, by the use of HPV mRNA expression is well studied in cervical cancer, but seldom studied in penile cancer. The aim was to determine prevalence of HPV types in fresh tissue of penile cancers compared to non-malignant age-matched penile controls. Additional aims were to analyze the viral expression and copy numbers of HPV16-positive tumors and 10 mm adjacent to the tumor. Methods: Fresh tissue from penile cancer cases was biopsied inside the tumor and 10 mm outside the tumor. Controls were males circumcised for non-malignant reasons, biopsied at surgery. PCR and Luminex assays were used for identification of HPV types. HPV16-positive samples were investigated for copy numbers and expression of HPV16-mRNA. Results: Among tumors (n = 135) and age-matched controls (n = 105), HPV was detected in 38.5% (52/135) and 11.4% (12/105), respectively (p < 0.001), adjusted odds ratio 12.8 (95% confidence interval 4.9–33.6). High-risk HPV types were found in 35.6% (48/135) of tumors and 4.8% (5/105) of controls (p < 0.001). Among tumors and controls, HPV16 was present in 27.4% (37/135) and 1% (1/105), respectively (p < 0.001). Among HPV16-positive penile cancers, mean HPV16 viral copy/cell was 74.4 (range 0.00003–725.4) in the tumor and 1.6 (range 0.001–14.4) 10 mm adjacent from the tumor. HPV16-mRNA analysis of the tumors and 10 mm adjacent from the tumors demonstrated viral activity in 86.5% (32/37) and 21.7% (5/23), respectively. Conclusions: The prevalence of HPV was significantly higher in penile cancer (38.5%) than among age-matched non-malignant penile samples (11.4%). HPV16 predominates (27.4%) in penile tumors. HPV16 expression was more common in penile cancer than in adjacent healthy tissue, strongly suggesting an etiological role for HPV16 in the development of penile cancer.
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27. |
- Laurenius, Anna, et al.
(författare)
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Resolution of diabetes, gastrointestinal symptoms, and self-reported dietary intake after gastric bypass versus sleeve gastrectomy: a randomized study
- 2023
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Ingår i: Surgery for Obesity and Related Diseases. - : Elsevier BV. - 1550-7289 .- 1878-7533. ; 19:5, s. 440-448
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Tidskriftsartikel (refereegranskat)abstract
- Background: There is a lack of randomized studies examining diabetes remission and dietary intake between patients undergoing Roux-en-Y gastric bypass (RYGB) versus sleeve gastrectomy (SG). Objective: To examine longitudinal differences in diabetes resolution, dietary intake, and gastrointestinal (GI) symptoms in patients with obesity and type 2 diabetes (T2D) randomized to either RYGB or SG and according to remission of T2D. Setting: Four hospitals in Sweden, 2 of which are university hospitals. Methods: Dietary intake and GI symptoms were calculated from questionnaires and morphometric differences between surgical methods and T2D remission were compared using the Student t test, effect size (ES) for parametric parameters, and Mann-Whitney U test for nonparametric parameters. Results: Five years after RYGB or SG there was no significant difference in the rate of remission of T2D between RYGB and SG (43% versus 20%, P = .176). RYGB (n = 19) patients had greater weight loss than SG patients (n = 14) (26.4 [9.5] versus 13.1 [9.6] kg, P < .001), despite reporting higher daily caloric intake (Δ 669 kcal, P = .059, ES .67) and food weight (Δ 1029 g/d, P = .003, ES 1.11). RYGB patients, compared with SG patients, also ate 1 more fruit per day (P = .023). Pooled data showed no differences between patients with and without T2D remission regarding weight loss, but those in remission drank more nonalcoholic drinks and milk. Conclusions: Five years postoperatively, patients randomized to RYGB reported considerably higher food intake compared with SG despite lower body weight. The reason and importance of the higher food intake after RYGB compared with SG needs to be further studied.
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28. |
- Lindroth, Ylva, et al.
(författare)
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Cervix cytology samples revealed increased methylation of the human markers FAM19A4/miR124-2 up to 8 years before adenocarcinoma
- 2024
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Ingår i: Acta Obstetricia et Gynecologica Scandinavica. - 0001-6349. ; 103:2, s. 378-386
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Methylation analysis of the promoter region of tumor-suppressor genes has previously shown high sensitivity for detection of high-grade cervical intraepithelial neoplasia (CIN) and cancer. HPV-testing has a high sensitivity to identify women at risk to develop cancer, and has been implemented in cervical screening programs in several countries. But in most HPV-positive women the infection will clear and they will not develop cancer. Testing for methylation could help to identify women who have potentially progressive cervical disease and need closer follow-up. The goal of the present study was to investigate the potential use of methylation as a triage test of HPV-positive women in the screening program. Material and methods: A collection of liquid-based cytology (LBC) samples from 106 women, collected between 4 months and 8 years before histologically confirmed cervical cancer or CIN3, was analysed for hypermethylation of the human genes FAM19A4 and miR124-2. Results: Methylation was detected in 45% (33/73) of normal LBC samples from women who later developed CIN3+, compared with 10% (3/31) of normal LBC samples from women without subsequent dysplasia (P = 0.0006). Overall, methylation was detected in 39% (14/36), 51% (19/37), 61% (14/23) and 70% (7/10) of LBC samples from women who later developed CIN3, adenocarcinoma in situ (AIS), squamous cell carcinoma (SCC) and adenocarcinoma (ADC), respectively. Positive methylation analysis was not significantly more frequent than abnormal cytology of atypical squamous cells of unclear significance or worse (ASCUS+) in LBC samples collected 4 months to 8 years before SCC or AIS; however, prior to the development of ADC, methylation was observed in 7/10 LBC samples, despite normal cytology. Overall, LBC samples collected before invasive cancer (ADC and SCC) were more frequently positive in the methylation analysis than in cytological analysis of ASCUS+ (P = 0.048). For LBC samples collected more than 2 years before the development of AIS, SCC or ADC, methylation analysis showed a higher positivity rate than cytology did. Conclusions: Testing for methylation of FAM19A4/miR124-2 as a triage for HPV-positive women would be useful to identify women at risk of cancer development, especially adenocarcinoma. Further studies are needed to estimate the cost-effectiveness before introducing methylation testing in the screening program.
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29. |
- Ma, Le Anh, et al.
(författare)
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Na-ion mobility in P2-type Na0.5MgxNi0.17-xMn0.83O2 (0
- 2021
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Ingår i: Physical Chemistry Chemical Physics. - : Royal Society of Chemistry (RSC). - 1463-9084 .- 1463-9076. ; 23:42, s. 24478-24486
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Tidskriftsartikel (refereegranskat)abstract
- Sodium transition metal oxides with a layered structure are one of the most widely studied cathode materials for Na+-ion batteries. Since the mobility of Na+ in such cathode materials is a key factor that governs the performance of material, electrochemical and muon spin rotation and relaxation techniques are here used to reveal the Na+-ion mobility in a P2-type Na0.5MgxNi0.17-xMn0.83O2 (x = 0, 0.02, 0.05 and 0.07) cathode material. Combining electrochemical techniques such as galvanostatic cycling, cyclic voltammetry, and the galvanostatic intermittent titration technique with mu+SR, we have successfully extracted both self-diffusion and chemical-diffusion under a potential gradient, which are essential to understand the electrode material from an atomic-scale viewpoint. The results indicate that a small amount of Mg substitution has strong effects on the cycling performance and the Na+ mobility. Amongst the tested cathode systems, it was found that the composition with a Mg content of x = 0.02 resulted in the best cycling stability and highest Na+ mobility based on electrochemical and mu+SR results. The current study clearly shows that for developing a new generation of sustainable energy-storage devices, it is crucial to study and understand both the structure as well as dynamics of ions in the material on an atomic level.
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30. |
- Ma, Le Anh, 1992-, et al.
(författare)
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Na-ion mobility in P2-type Na0.5MgxNi0.17-xMn0.83O2 (0 <= x <= 0.07) from electrochemical and muon spin relaxation studies
- 2021
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Ingår i: Physical Chemistry, Chemical Physics - PCCP. - : Royal Society of Chemistry (RSC). - 1463-9076 .- 1463-9084. ; 23:42, s. 24478-24486
-
Tidskriftsartikel (refereegranskat)abstract
- Sodium transition metal oxides with a layered structure are one of the most widely studied cathode materials for Na+-ion batteries. Since the mobility of Na+ in such cathode materials is a key factor that governs the performance of material, electrochemical and muon spin rotation and relaxation techniques are here used to reveal the Na+-ion mobility in a P2-type Na0.5MgxNi0.17-xMn0.83O2 (x = 0, 0.02, 0.05 and 0.07) cathode material. Combining electrochemical techniques such as galvanostatic cycling, cyclic voltammetry, and the galvanostatic intermittent titration technique with mu+SR, we have successfully extracted both self-diffusion and chemical-diffusion under a potential gradient, which are essential to understand the electrode material from an atomic-scale viewpoint. The results indicate that a small amount of Mg substitution has strong effects on the cycling performance and the Na+ mobility. Amongst the tested cathode systems, it was found that the composition with a Mg content of x = 0.02 resulted in the best cycling stability and highest Na+ mobility based on electrochemical and mu+SR results. The current study clearly shows that for developing a new generation of sustainable energy-storage devices, it is crucial to study and understand both the structure as well as dynamics of ions in the material on an atomic level.
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31. |
- Matsubara, Nami, et al.
(författare)
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Cation Distributions and Magnetic Properties of Ferrispinel MgFeMnO4
- 2020
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Ingår i: Inorganic Chemistry. - : American Chemical Society (ACS). - 0020-1669 .- 1520-510X. ; 59:24, s. 17970-17980
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Tidskriftsartikel (refereegranskat)abstract
- The crystal structure and magnetic properties of the cubic spinel MgFeMnO4 were studied by using a series of in-house techniques along with large-scale neutron diffraction and muon spin rotation spectroscopy in the temperature range between 1.5 and 500 K. The detailed crystal structure is successfully refined by using a cubic spinel structure described by the space group Fd3¯ m. Cations within tetrahedral A and octahedral B sites of the spinel were found to be in a disordered state. The extracted fractional site occupancies confirm the presence of antisite defects, which are of importance for the electrochemical performance of MgFeMnO4 and related battery materials. Neutron diffraction and muon spin spectroscopy reveal a ferrimagnetic order below TC = 394.2 K, having a collinear spin arrangement with antiparallel spins at the A and B sites, respectively. Our findings provide new and improved understanding of the fundamental properties of the ferrispinel materials and of their potential applications within future spintronics and battery devices.
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32. |
- Matsubara, Nami, et al.
(författare)
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Magnetism and ion diffusion in honeycomb layered oxide K 2Ni 2TeO 6
- 2020
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322 .- 2045-2322. ; 10:1
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Tidskriftsartikel (refereegranskat)abstract
- In the quest for developing novel and efficient batteries, a great interest has been raised for sustainable K-based honeycomb layer oxide materials, both for their application in energy devices as well as for their fundamental material properties. A key issue in the realization of efficient batteries based on such compounds, is to understand the K-ion diffusion mechanism. However, investigation of potassium-ion (K+) dynamics in materials using e.g. NMR and related techniques has so far been very challenging, due to its inherently weak nuclear magnetic moment, in contrast to other alkali ions such as lithium and sodium. Spin-polarised muons, having a high gyromagnetic ratio, make the muon spin rotation and relaxation (μ+SR) technique ideal for probing ions dynamics in these types of energy materials. Here we present a study of the low-temperature magnetic properties as well as K+ dynamics in honeycomb layered oxide material K 2Ni 2TeO 6 using mainly the μ+SR technique. Our low-temperature μ+SR results together with complementary magnetic susceptibility measurements find an antiferromagnetic transition at TN≈ 27 K. Further μ+SR studies performed at higher temperatures reveal that potassium ions (K+) become mobile above 200 K and the activation energy for the diffusion process is obtained as Ea= 121 (13) meV. This is the first time that K+ dynamics in potassium-based battery materials has been measured using μ+SR. Assisted by high-resolution neutron diffraction, the temperature dependence of the K-ion self diffusion constant is also extracted. Finally our results also reveal that K-ion diffusion occurs predominantly at the surface of the powder particles. This opens future possibilities for potentially improving ion diffusion as well as K-ion battery device performance using nano-structuring and surface coatings of the particles.
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33. |
- Matsubara, Nami, et al.
(författare)
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Magnetism and ion diffusion in honeycomb layered oxide K2Ni2TeO6
- 2020
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Ingår i: Scientific Reports. - : Springer Nature. - 2045-2322. ; 10:1
-
Tidskriftsartikel (refereegranskat)abstract
- In the quest for developing novel and efficient batteries, a great interest has been raised for sustainable K-based honeycomb layer oxide materials, both for their application in energy devices as well as for their fundamental material properties. A key issue in the realization of efficient batteries based on such compounds, is to understand the K-ion diffusion mechanism. However, investigation of potassium-ion (K+) dynamics in materials using e.g. NMR and related techniques has so far been very challenging, due to its inherently weak nuclear magnetic moment, in contrast to other alkali ions such as lithium and sodium. Spin-polarised muons, having a high gyromagnetic ratio, make the muon spin rotation and relaxation (mu+SR) technique ideal for probing ions dynamics in these types of energy materials. Here we present a study of the low-temperature magnetic properties as well as K+ dynamics in honeycomb layered oxide material K2Ni2TeO6 using mainly the mu+SR technique. Our low-temperature mu+SR results together with complementary magnetic susceptibility measurements find an antiferromagnetic transition at T-N approximate to 27 K. Further mu+SR studies performed at higher temperatures reveal that potassium ions (K+) become mobile above 200 K and the activation energy for the diffusion process is obtained as E-a = 121(13) meV. This is the first time that K+ dynamics in potassium-based battery materials has been measured using mu+SR. Assisted by high-resolution neutron diffraction, the temperature dependence of the K-ion self diffusion constant is also extracted. Finally our results also reveal that K-ion diffusion occurs predominantly at the surface of the powder particles. This opens future possibilities for potentially improving ion diffusion as well as K-ion battery device performance using nano-structuring and surface coatings of the particles.
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34. |
- Matsubara, Nami, et al.
(författare)
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Neutron powder diffraction study of NaMn2O4 and Li0.92Mn2O4 : Insights on spin-charge-orbital ordering
- 2020
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Ingår i: Physical Review Research. - : American Physical Society (APS). - 2643-1564. ; 2:4
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Tidskriftsartikel (refereegranskat)abstract
- High-pressure synthesized quasi-one-dimensional NaMn2O4 and Li0.92Mn2O4 are both antiferromagnetic insulators. Here their atomic and magnetic structures are investigated using neutron powder diffraction. The present crystal structural analyses of NaMn2O4 reveal that a Mn3+/Mn4+ charge-ordering state exists even at low temperature (down to 1.5 K). It is evident that one of the Mn sites shows a strongly distorted Mn3+ octahedron due to the Jahn-Teller effect. Above TN=35 K, a two-dimensional short-range correlation is observed, as indicated by asymmetric diffuse scattering. Below TN, two antiferromagnetic transitions are observed: (i) a commensurate long-range Mn3+ spin ordering below TN1=35 K and (ii) an incommensurate Mn4+ spin ordering below TN2=11 K. Surprisingly, the two antiferromagnetic orders are found to be independent of each other. The commensurate magnetic structure (kC=0.5,0.5,0.5) follows the magnetic anisotropy of the local easy axes of Mn3+, while the incommensurate Mn4+ one shows a spin-density-wave or a cycloidal order with kIC=(0,0,0.216). For Li0.92Mn2O4, on the other hand, the absence of a long-range spin-ordered state is confirmed down to 1.5 K.
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35. |
- Mekuria, Selamawit, et al.
(författare)
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Detection of HPV mRNA in Self-collected Vaginal Samples Among Urban Ethiopian Women
- 2020
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Ingår i: Anticancer research. - : Anticancer Research USA Inc.. - 1791-7530 .- 0250-7005. ; 40:3, s. 1513-1517
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND/AIM: Cervical cancer is the most common cancer among women in Ethiopia. The objective was to evaluate the participation rate of a free of charge vaginal self-sample (Aptima multitest swab, Hologic) for the detection of human papillomavirus (HPV) in an Ethiopian cohort. PATIENTS AND METHODS: Specimens were collected from women employed by Ethiopian Airlines in Addis Abeba (N=5950). Samples were analysed for the presence of high-risk (HR) HPV mRNA by the Aptima HPV assay (Hologic) and HPV positive women were referred for cytology. Identification of HPV types among HPV positive samples was performed by Modified general primer-PCR and Luminex assay. RESULTS: Participation rate was 3.1% and the prevalence of HPV mRNA was 20.6% (37/180). CONCLUSION: Primary HPV mRNA screening with vaginal self-sampling may be an acceptable approach in Ethiopia. One out of five women harbor HPV in their vaginal self-sample in agreement with other similar studies from the region.
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36. |
- Miniotaite, Ugne, et al.
(författare)
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Magnetic Properties of Multifunctional 7 LiFePO 4 under Hydrostatic Pressure
- 2023
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Ingår i: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 2462:1
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Konferensbidrag (refereegranskat)abstract
- LiFePO4 (LFPO) is an archetypical and well-known cathode material for rechargeable Li-ion batteries. However, its quasi-one-dimensional (Q1D) structure along with the Fe ions, LFPO also displays interesting low-temperature magnetic properties. Our team has previously utilized the muon spin rotation (μ +SR) technique to investigate both magnetic spin order as well as Li-ion diffusion in LFPO. In this initial study we extend our investigation and make use of high-pressure μ +SR to investigate effects on the low-T magnetic order. Contrary to theoretical predictions we find that the magnetic ordering temperature as well as the ordered magnetic moment increase at high pressure (compressive strain).
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37. |
- Miniotaite, Ugne, et al.
(författare)
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Magnetic Properties of Multifunctional (LiFePO4)-Li-7 under Hydrostatic Pressure
- 2023
-
Ingår i: Proceedings 15th International Conference on Muon Spin Rotation, Relaxation and Resonance (SR). - : IOP Publishing.
-
Konferensbidrag (refereegranskat)abstract
- LiFePO4 (LFPO) is an archetypical and well-known cathode material for rechargeable Li-ion batteries. However, its quasi-one-dimensional (Q1D) structure along with the Fe ions, LFPO also displays interesting low-temperature magnetic properties. Our team has previously utilized the muon spin rotation (mu+SR) technique to investigate both magnetic spin order as well as Li-ion diffusion in LFPO. In this initial study we extend our investigation and make use of high-pressure mu+SR to investigate effects on the low-T magnetic order. Contrary to theoretical predictions we find that the magnetic ordering temperature as well as the ordered magnetic moment increase at high pressure (compressive strain).
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38. |
- Nilsson, Johan S., et al.
(författare)
-
Immune phenotypes of nasopharyngeal cancer
- 2020
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Ingår i: Cancers. - : MDPI AG. - 2072-6694. ; 12:11, s. 1-17
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Tidskriftsartikel (refereegranskat)abstract
- Nasopharyngeal cancer (NPC) features intralesional immune cells, but data are lacking on presence/distribution of T-cells and dendritic cells (DCs). Based on intralesional distribution of lymphocytes, a series of NPC biopsies (n = 48) were classified into “inflamed”, “excluded”, and “deserted” phenotypes. In addition, CD8+ T-cells and CD207+ DCs were quantified. The data were analyzed in relation to Epstein–Barr virus-encoded small RNA (EBER), Epstein-Barr virus (EBV) DNA, and survival. Separately, data on gene expression from a public database were analyzed. 61.7% of NPC lesions were “inflamed”, 29.8% were “excluded”, and 8.5% were “deserted”. While CD8+ cells were present in cancer cell areas and in surrounding stroma, CD207+ cells were observed largely in cancer cell areas. High CD8+ T-cell presence was associated with EBV+ disease, but no such pattern was observed for CD207+ DCs. There was a difference in disease-free survival in favor of “inflamed” over “excluded” NPC. Gene expression analysis revealed differences between NPC and control tissue (e.g., with regard to interferon activity) as well as between subgroups of NPC based on CD8 expression (high vs. low). In conclusion, NPC lesions are heterogeneous with regard to distribution of CD8+ T-cells and CD207+ DCs. NPC can be classified into immune phenotypes that carry prognostic information. CD207+ DCs may represent a target for immunotherapy with potential to facilitate the antigen cross-presentation necessary to execute cytotoxic T-lymphocyte responses.
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39. |
- Nocerino, E., et al.
(författare)
-
Competition between magnetic interactions and structural instabilities leading to itinerant frustration in the triangular lattice antiferromagnet LiCrSe 2
- 2023
-
Ingår i: Communications Materials. - 2662-4443. ; 4:1
-
Tidskriftsartikel (refereegranskat)abstract
- LiCrSe2 constitutes a recent valuable addition to the ensemble of two-dimensional triangular lattice antiferromagnets. In this work, we present a comprehensive study of the low temperature nuclear and magnetic structure established in this material. Being subject to a strong magnetoelastic coupling, LiCrSe2 was found to undergo a first order structural transition from a trigonal crystal system (P3 ¯ m1) to a monoclinic one (C2/m) at T s = 30 K. Such restructuring of the lattice is accompanied by a magnetic transition at T N = 30 K. Refinement of the magnetic structure with neutron diffraction data and complementary muon spin rotation analysis reveal the presence of a complex incommensurate magnetic structure with a up-up-down-down arrangement of the chromium moments with ferromagnetic double chains coupled antiferromagnetically. The spin axial vector is also modulated both in direction and modulus, resulting in a spin density wave-like order with periodic suppression of the chromium moment along the chains. This behavior is believed to appear as a result of strong competition between direct exchange antiferromagnetic and superexchange ferromagnetic couplings established between both nearest neighbor and next nearest neighbor Cr3+ ions. We finally conjecture that the resulting magnetic order is stabilized via subtle vacancy/charge order within the lithium layers, potentially causing a mix of two co-existing magnetic phases within the sample.
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40. |
- Nocerino, Elisabetta, et al.
(författare)
-
Competition between magnetic interactions and structural instabilities leading to itinerant frustration in the triangular lattice antiferromagnet LiCrSe2
- 2023
-
Ingår i: Communications Materials. - : Springer Nature. - 2662-4443. ; 4:1
-
Tidskriftsartikel (refereegranskat)abstract
- LiCrSe2 constitutes a recent valuable addition to the ensemble of two-dimensional triangular lattice antiferromagnets. In this work, we present a comprehensive study of the low temperature nuclear and magnetic structure established in this material. Being subject to a strong magnetoelastic coupling, LiCrSe2 was found to undergo a first order structural transition from a trigonal crystal system (P3 ¯ m1) to a monoclinic one (C2/m) at T s = 30 K. Such restructuring of the lattice is accompanied by a magnetic transition at T N = 30 K. Refinement of the magnetic structure with neutron diffraction data and complementary muon spin rotation analysis reveal the presence of a complex incommensurate magnetic structure with a up-up-down-down arrangement of the chromium moments with ferromagnetic double chains coupled antiferromagnetically. The spin axial vector is also modulated both in direction and modulus, resulting in a spin density wave-like order with periodic suppression of the chromium moment along the chains. This behavior is believed to appear as a result of strong competition between direct exchange antiferromagnetic and superexchange ferromagnetic couplings established between both nearest neighbor and next nearest neighbor Cr3+ ions. We finally conjecture that the resulting magnetic order is stabilized via subtle vacancy/charge order within the lithium layers, potentially causing a mix of two co-existing magnetic phases within the sample.
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41. |
- Nocerino, E., et al.
(författare)
-
Magnetic nature of wolframite MgReO 4
- 2023
-
Ingår i: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 2462:1
-
Konferensbidrag (refereegranskat)abstract
- Rhenium oxides belonging to the family AReO4 where A is a metal cation, exhibit interesting electronic and magnetic properties. In this study we have utilized the muon spin rotation/relaxation (μ +SR) technique to study the magnetic properties of the MgReO4 compound. To the best of our knowledge, this is the first investigation reported on this interesting material, that is stabilized in a wolframite crystal structure using a special high-pressure synthesis technique. Bulk magnetic studies show the onset of an antiferromagnetic (AF) long range order, or a possible singlet spin state at T C1 ≈ 90 K, with a subtle second high-temperature transition at T C2 ≈ 280 K. Both transitions are also confirmed by heat capacity (Cp ) measurements. From our μ +SR measurements, it is clear that the sample enters an AF order below T C1 = T N ≈ 85 K. We find no evidence of magnetic signal above T N, which indicates that T C2 is likely linked to a structural transition. Further, via sensitive zero field (ZF) μ +SR measurements we find evidence of a spin reorientation at T Cant ≈ 65 K. This points towards a transition from a collinear AF into a canted AF order at low temperature, which is proposed to be driven by competing magnetic interactions.
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42. |
- Nocerino, Elisabetta, et al.
(författare)
-
Magnetic nature of wolframite MgReO4
- 2023
-
Ingår i: 15th International Conference on Muon Spin Rotation, Relaxation and Resonance, MuSR 2022. - : IOP Publishing.
-
Konferensbidrag (refereegranskat)abstract
- Rhenium oxides belonging to the family AReO4 where A is a metal cation, exhibit interesting electronic and magnetic properties. In this study we have utilized the muon spin rotation/relaxation (mu+SR) technique to study the magnetic properties of the MgReO4 compound. To the best of our knowledge, this is the first investigation reported on this interesting material, that is stabilized in a wolframite crystal structure using a special highpressure synthesis technique. Bulk magnetic studies show the onset of an antiferromagnetic (AF) long range order, or a possible singlet spin state at T-C1 approximate to 90 K, with a subtle second hightemperature transition at T-C2 approximate to 280 K. Both transitions are also confirmed by heat capacity (Cp) measurements. From our mu+SR measurements, it is clear that the sample enters an AF order below T-C1 = T-N approximate to 85 K. We find no evidence of magnetic signal above TN, which indicates that T-C2 is likely linked to a structural transition. Further, via sensitive zero field (ZF) mu(+) SR measurements we find evidence of a spin reorientation at T-Cant approximate to 65 K. This points towards a transition from a collinear AF into a canted AF order at low temperature, which is proposed to be driven by competing magnetic interactions.
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43. |
- Nocerino, Elisabetta, et al.
(författare)
-
Na-ion dynamics in the solid solution NaxCa1−xCr2O4 studied by muon spin rotation and neutron diffraction
- 2024
-
Ingår i: Sustainable Energy & Fuels. - : ROYAL SOC CHEMISTRY. - 2398-4902. ; 8:7
-
Tidskriftsartikel (refereegranskat)abstract
- In this work we present a systematic set of measurements carried out by muon spin rotation/relaxation (mu+SR) and neutron powder diffraction (NPD) on the solid solution NaxCa1-xCr2O4. This study investigates Na-ion dynamics in the quasi-1D (Q1D) diffusion channels created by the honeycomb-like arrangement of CrO6 octahedra, in the presence of defects introduced by Ca substitution. With increasing Ca content, the size of the diffusion channels is enlarged; however, this effect does not enhance the Na ion mobility. Instead the overall diffusivity is hampered by the local defects and the Na hopping probability is lowered. The diffusion mechanism in NaxCa1-xCr2O4 is proposed to be interstitial and the activation energy as well as diffusion coefficient are determined for all the members of the solid solution.
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44. |
- Nocerino, Elisabetta, et al.
(författare)
-
Nuclear and magnetic spin structure of the antiferromagnetic triangular lattice compound LiCrTe 2 investigated by μ + SR, neutron and X-ray diffraction
- 2022
-
Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322 .- 2045-2322. ; 12:1
-
Tidskriftsartikel (refereegranskat)abstract
- Two-dimensional (2D) triangular lattice antiferromagnets (2D-TLA) often manifest intriguing physical and technological properties, due to the strong interplay between lattice geometry and electronic properties. The recently synthesized 2-dimensional transition metal dichalcogenide LiCrTe2, being a 2D-TLA, enriched the range of materials which can present such properties. In this work, muon spin rotation (μ+SR) and neutron powder diffraction (NPD) have been utilized to reveal the true magnetic nature and ground state of LiCrTe2. From high-resolution NPD the magnetic spin order at base-temperature is not, as previously suggested, helical, but rather collinear antiferromagnetic (AFM) with ferromagnetic (FM) spin coupling within the ab-plane and AFM coupling along the c-axis. The value if the ordered magnetic Cr moment is established as μCr=2.36μB. From detailed μ+SR measurements we observe an AFM ordering temperature TN≈ 125 K. This value is remarkably higher than the one previously reported by magnetic bulk measurements. From μ+SR we are able to extract the magnetic order parameter, whose critical exponent allows us to categorize LiCrTe2 in the 3D Heisenberg AFM universality class. Finally, by combining our magnetic studies with high-resolution synchrotron X-ray diffraction (XRD), we find a clear coupling between the nuclear and magnetic spin lattices. This suggests the possibility for a strong magnon–phonon coupling, similar to what has been previously observed in the closely related compound LiCrO2.
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45. |
- Nocerino, E., et al.
(författare)
-
Unusually large magnetic moment and tricritical behavior of the CMR compound NaCr 2 O 4 revealed with high resolution neutron diffraction and μ + SR
- 2023
-
Ingår i: JPhys Materials. - 2515-7639. ; 6:3
-
Tidskriftsartikel (refereegranskat)abstract
- The mixed valence Cr3+/Cr4+ compound NaCr2O4, hosts a plethora of unconventional electronic properties. In the present study, muon spin rotation/relaxation ( μ + SR) and high-resolution time-of-flight neutron powder diffraction measurements were carried out on high-quality samples to clarify the complex magnetic ground state of this unique material. We identified a commensurate canted antiferromagnetic order (C-AFM) with a canting angle of the Cr spin axial vector equal to θ c = ( 8.8 ± 0.5 ) ∘ , and an estimated Cr moment μ C r C ∼ ( 4.30 ± 0.01 ) μ B . Such an unusually large value of μ C r C is compatible with the existence of high-spin Cr sites created by the presence of an unconventional negative charge transfer state in NaCr2O4. In addition to the C-AFM structure, a novel magnetic supercell was also revealed. Such supercell display an incommensurate (IC)-AFM propagation vector (0 0 1 2 − δ ), having a Cr moment μ C r I C = ( 2.20 ± 0.03 ) μ B . It is suggested that the C-AFM and IC-AFM modulations have two different electronic origins, being due to itinerant and localized contributions to the magnetic moment respectively. Finally, the direct measurement of the magnetic order parameter for the C-AFM structure provided a value of the critical exponent β = 0.245 ≈ 1 4 , suggesting a non conventional critical behavior for the magnetic phase transition in NaCr2O4
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46. |
- Nocerino, Elisabetta, et al.
(författare)
-
Unusually large magnetic moment and tricritical behavior of the CMR compound NaCr2O4 revealed with high resolution neutron diffraction and mu(+) SR
- 2023
-
Ingår i: Journal of Physics. - : IOP Publishing. - 2515-7639. ; 6:3
-
Tidskriftsartikel (refereegranskat)abstract
- The mixed valence Cr3+/Cr4+ compound NaCr2O4, hosts a plethora of unconventional electronic properties. In the present study, muon spin rotation/relaxation (mu(+) SR) and high-resolution time-of-flight neutron powder diffraction measurements were carried out on high-quality samples to clarify the complex magnetic ground state of this unique material. We identified a commensurate canted antiferromagnetic order (C-AFM) with a canting angle of the Cr spin axial vector equal to theta
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47. |
- Ohishi, Kazuki, et al.
(författare)
-
The internal magnetic field in a ferromagnetic compound Y 2 Co 12 P 7
- 2023
-
Ingår i: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 2462:1
-
Konferensbidrag (refereegranskat)abstract
- The internal magnetic field in a ferromagnetic compound, Y2Co12P7 with T C = 150 K, was studied with μ +SR using a powder sample down to 2 K. The wTF-μ +SR measurements revealed the presence of a sharp magnetic transition at T C = 151 K, and the ZF-μ +SR measurements clarified the formation of static magnetic order below T C. The presence of two muon spin precession signals in the ZF-μ +SR spectrum below T C indicates the existence of the two different muon sites in the lattice. By considering the muon sites and local spin densities at the muon sites predicted with DFT calculations, the ordered magnetic moments of Co were successfully determined.
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48. |
- Ohishi, Kazuki, et al.
(författare)
-
The internal magnetic field in a ferromagnetic compound Y2Co12P7
- 2023
-
Ingår i: Proceedings 15th International Conference on Muon Spin Rotation, Relaxation and Resonance (SR). - : IOP Publishing. ; 2462
-
Konferensbidrag (refereegranskat)abstract
- The internal magnetic field in a ferromagnetic compound, Y2Co12P7 with T-C = 150 K, was studied with mu(+) SR using a powder sample down to 2 K. The wTF-mu(+) SR measurements revealed the presence of a sharp magnetic transition at T-C = 151 K, and the ZF-mu(+) SR measurements clarified the formation of static magnetic order below T-C. The presence of two muon spin precession signals in the ZF-mu(+) SR spectrum below TC indicates the existence of the two different muon sites in the lattice. By considering the muon sites and local spin densities at the muon sites predicted with DFT calculations, the ordered magnetic moments of Co were successfully determined.
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49. |
- Palm, Rasmus, et al.
(författare)
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In situ neutron diffraction of NaAlD4/carbon black composites during decomposition/deuteration cycles and the effect of carbon on phase segregation
- 2022
-
Ingår i: International journal of hydrogen energy. - : Elsevier BV. - 0360-3199 .- 1879-3487. ; 47:80, s. 34195-34204
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Tidskriftsartikel (refereegranskat)abstract
- The influence on the decomposition and reforming of the hydrogen storage material NaAlH4 by adding relatively low amounts of mesoporous carbon black is investigated with in situ diffraction. A 60:40 NaAlH4/carbon black composite is prepared via ball milling and characterised ex situ via X-ray diffraction, gas adsorption, temperature-programmed decomposition, and dehydrogenation/hydrogenation cycling methods. The prepared composite is deuterated, and the crystalline phase composition is determined with in situ neutron powder diffraction method during multiple decomposition/deuteration cycles. Changes in the crystalline phase composition start slightly below the melting temperature of the pristine alanate, whereas the release of deuterium starts at considerably lower temperatures. The decomposition of Na3AlD6 to NaD is almost completely reversible at the applied low deuterium pressures of >= 2 MPa. Thus, the strong effect of even low concen-trations of a mesoporous carbon black on the capability to store H2 reversibly is showcased and analysed in-depth.
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50. |
- Papadopoulos, Konstantinos, 1989, et al.
(författare)
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Influence of the magnetic sublattices in the double perovskite LaCaNiReO6
- 2022
-
Ingår i: Physical Review B. - : American Physical Society (APS). - 2469-9969 .- 2469-9950. ; 106:21
-
Tidskriftsartikel (refereegranskat)abstract
- The magnetism of double perovskites is a complex phenomenon, determined from intra- or interatomic magnetic moment interactions, and strongly influenced by geometry. We take advantage of the complementary length and timescales of the muon spin rotation, relaxation, and resonance (μ+SR) microscopic technique and bulk ac/dc magnetic susceptibility measurements to study the magnetic phases of the LaCaNiReO6 double perovskite. As a result, we are able to discern and report ferrimagnetic ordering below TC=102K and the formation of different magnetic domains above TC. Between TC270K. An evolution of the interaction between Ni and Re magnetic sublattices, in this geometrically frustrated fcc perovskite structure, is revealed as a function of temperature through the critical behavior and thermal evolution of microscopic and macroscopic physical quantities.
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