| 1. |
- Jarstad, Anna, 1966-, et al.
(författare)
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Three approaches to peace : a framework for describing and exploring varieties of peace
- 2019
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- For decades, peace and conflict studies have devoted more attention to conflict than to peace, and despiteits centrality, peace itself has been under-conceptualized. In this paper, we propose a theoretical frameworkand methodologies to make peace beyond the absence of war researchable. The framework is designed to capture varieties of peace between and beyond dichotomous conceptions of positive versus negative peace, or successful versus failed peace processes. To capture the complexity of peace in its empirical diversity, our framework approaches peace in three different ways: as a situation or condition in a particular locality; as a web of relationships; and as ideas or discourses about what peace is or should be. These approaches provide different avenues for researching peace, and taken together they provide a fuller picture of what peace is, how it is manifested, experienced, and understood. We argue that this framework provides a way forward in advancing conceptual understandings and empirical analyses of peace that can facilitate systematic, comparative, qualitative analyses while at the same time accounting for the complex, multifaceted nature of peace.
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| 2. |
- Jarstad, Anna, et al.
(författare)
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Varieties of peace : presentation of a research program
- 2017
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The Varieties of Peace research program aims to analyze long-term effects of peace processes in conflicts that ended in the 1990s. The central research questions are: What characterizes peace after the peace processes initiated in the 1990s and how does it vary? How can this variation be described and explained? Peace processes have been studied using short time perspectives, usually in "lessons-learned" evaluations five years after conflict termination, and usually with theories of conflict as a starting point. The Varieties of Peace research program is an ambitious initiative, which starts from a theoretical understanding of peace, its quality and character, and views peace and peace processes as dynamic and transformative. It will investigate and evaluate different types of peace processes from a comparative perspective and 25–30 years after they started, with the ambition of producing generalizable knowledge about peace, what it is and how it can be achieved. As a starting point, the program studies explanatory factors in five areas: 1) the actions, capacity and resilience of civil society, 2) the interests and strategies of the elites, 3) the aims and character of the agreements, 4) the societies' institutions and resilience, and 5) international involvement. These issues will be studies in at least ten projects, with the ambition to capture and explain variation, internal dynamics and ultimately the results and effects of peace processes, studied over a longer period of time. The Varieties of Peace program is funded by Riksbankens Jubileumsfond: the Swedish Foundation for Humanities and Social Sciences, 2017-2024. For more info, please visit our webpage at www.varietiesofpeace.net.
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| 3. |
- Abuzeid, Nadir, et al.
(författare)
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Antimycobacterial activity of selected medicinal plants traditionally used in Sudan to treat infectious diseases
- 2014
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Ingår i: Journal of Ethnopharmacology. - : Elsevier. - 0378-8741 .- 1872-7573. ; 157, s. 134-139
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Tidskriftsartikel (refereegranskat)abstract
- Ethnopharmacological relevance: The emergence of multidrug-resistant strains of Mycobacterium tuberculosis underscores the need for continuous development of new and efficient methods to determine the susceptibility of isolates of Mycobacterium tuberculosis in the search for novel antimycobacterial agents. Natural products constitute an important source of new drugs, and design and implementation of antimycobacterial susceptibility testing methods are necessary to evaluate the different extracts and compounds. In this study we have explored the antimycobacterial properties of 50 ethanolic extracts from different parts of 46 selected medicinal plants traditionally used in Sudan to treat infectious diseases. Materials and methods: Plants were harvested and ethanolic extracts were prepared. For selected extracts, fractionation with hydrophilic and hydrophobic solvents was undertaken. A luminometry-based assay was used for determination of mycobacterial growth in broth cultures and inside primary human macrophages in the presence or absence of plant extracts and fractions of extracts. Cytotoxicity was also assessed for active fractions of plant extracts. Results: Of the tested extracts, three exhibited a significant inhibitory effect on an avirulent strain of Mycobacterium tubercluosis (H37Ra) at the initial screening doses (125 and 6.25 mu g/ml). These were bark and leaf extracts of Khaya senegalensis and the leaf extract of Rosmarinus officinalis L. Further fractions of these plant extracts were prepared with n-hexane, chloroform, ethyl acetate, n-butanol, ethanol and water, and the activity of these extracts was retained in hydrophobic fractions. Cytotoxicity assays revealed that the chloroform fraction of Khaya senegalensis bark was non-toxic to human monocyte-derived macrophages and other cell types at the concentrations used and hence, further analysis, including assessment of IC50 and intracellular activity was done with this fraction. Conclusion: These results encourage further investigations to identify the active compound(s) within the chloroform fraction of Khaya senegalensis bark. (C) 2014 Elsevier Ireland Ltd. All rights reserved.
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| 4. |
- Ahl, Amanda, et al.
(författare)
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Balancing formal and informal success factors perceived by supply chain stakeholders : A study of woody biomass energy systems in Japan
- 2018
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Ingår i: Journal of Cleaner Production. - : Elsevier. - 0959-6526 .- 1879-1786. ; 175, s. 50-59
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Tidskriftsartikel (refereegranskat)abstract
- Small-scale woody biomass energy systems have an inherent ability to aid in emissions reduction while stimulating local economies and, as collective energy systems, are strongly connected to supply chain design based on local conditions and stakeholder integration. Despite an abundance of forest area alongside the promotion of biomass in energy policies, however, woody biomass utilization still remains low in Japan. The woody biomass supply chain, considered as a socio-technical system, involves a complex, cross-sectoral stakeholder network in which inter-organizational dynamics necessitates well-organized management based on an understanding of formal factors such as technology, as well as informal factors such as social relations and culture. In this paper, success factor perceptions from across the woody biomass supply chain are investigated based on semi-structured interviews with four stakeholders in the Kyushu region of Japan. Identified success factors here are: 1) respect of values & traditions, 2) transportation infrastructure, 3) business model integration, 4) relationship & trust, 5) local vitalization and 6) biomass quality control. A convergence as well as divergence of perceptions are observed, involving both formal and informal dimensions. Aiming to balance perceptions and to enable long-term success of woody biomass in Japan, a series of policy implications are drawn, including cross-ministerial integration, knowledge building on wood logistics, forest certification, local coordinators, biomass quality control standards and a feed-in-tariff for heat. This paper suggests a new arena of policy-making based on the importance of considering both informal and formal dimensions in energy policy.
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| 5. |
- Alexius, Annika, et al.
(författare)
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The interbank market risk premium, central bank interventions, and measures of market liquidity
- 2014
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Ingår i: Journal of International Money and Finance. - : Elsevier BV. - 0261-5606 .- 1873-0639. ; 48, s. 202-217
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Tidskriftsartikel (refereegranskat)abstract
- When the interbank market risk premium soared during the financial crisis, it created a wedge between interest rates actually paid by private agents and the rapidly falling policy rates. Many central banks attempted to improve the situation by supplying liquidity to the domestic interbank market. This paper studies the Swedish interbank market risk premium using a unique data set on traded volume between banks and between banks and the Riksbank. We find that the main determinants of the Swedish interbank premium are international variables, such as US and EURO area risk premia. International exchange rate volatility and the EURO/USD deviations from CIP also matters, while standard measures of domestic market liquidity and domestic credit risk have insignificant effects. Nonlinear smooth transition (STR) models show that U.S. financial variables are more important in times of a rising U.S. risk premium. Our measure of actual turnover in the interbank market is associated with a significant reduction of the interbank market risk premium, as are credit provisions by the central bank.
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| 6. |
- Amano, Tatsuya, et al.
(författare)
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Transforming Practice : Checklists for Delivering Change
- 2022
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Ingår i: Transforming Conservation : A Practical Guide to Evidence and Decision Making - A Practical Guide to Evidence and Decision Making. - 9781800648562 - 9781800648586 ; , s. 367-386
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Bokkapitel (refereegranskat)abstract
- Delivering a revolution in evidence use requires a cultural change across society. For a wide range of groups (practitioners, knowledge brokers, organisations, organisational leaders, policy makers, funders, researchers, journal publishers, the wider conservation community, educators, writers, and journalists), options are described to facilitate a change in practice, and a series of downloadable checklists is provided.
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| 7. |
- Anasori, Babak, et al.
(författare)
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Experimental and theoretical characterization of ordered MAX phases Mo2TiAlC2 and Mo2Ti2AlC3
- 2015
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Ingår i: Journal of Applied Physics. - : AMER INST PHYSICS. - 0021-8979 .- 1089-7550. ; 118:9, s. 094304-
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Tidskriftsartikel (refereegranskat)abstract
- Herein, we report on the phase stabilities and crystal structures of two newly discovered ordered, quaternary MAX phases-Mo2TiAlC2 and Mo2Ti2AlC3-synthesized by mixing and heating different elemental powder mixtures of mMo:(3-m) Ti:1.1Al:2C with 1.5 less than= m less than= 2.2 and 2Mo: 2Ti:1.1Al:2.7C to 1600 degrees C for 4 h under Ar flow. In general, for m greater than= 2 an ordered 312 phase, (Mo2Ti) AlC2, was the majority phase; for mless than 2, an ordered 413 phase (Mo2Ti2)AlC3, was the major product. The actual chemistries determined from X-ray photoelectron spectroscopy (XPS) are Mo2TiAlC1.7 and Mo2Ti1.9Al0.9C2.5, respectively. High resolution scanning transmission microscopy, XPS and Rietveld analysis of powder X-ray diffraction confirmed the general ordered stacking sequence to be Mo-Ti-Mo-Al-Mo-Ti-Mo for Mo2TiAlC2 and Mo-Ti-Ti-Mo-Al-Mo-Ti-Ti-Mo for Mo2Ti2AlC3, with the carbon atoms occupying the octahedral sites between the transition metal layers. Consistent with the experimental results, the theoretical calculations clearly show that M layer ordering is mostly driven by the high penalty paid in energy by having the Mo atoms surrounded by C in a face-centered configuration, i.e., in the center of the Mn+1Xn blocks. At 331 GPa and 367 GPa, respectively, the Youngs moduli of the ordered Mo2TiAlC2 and Mo2Ti2AlC3 are predicted to be higher than those calculated for their ternary end members. Like most other MAX phases, because of the high density of states at the Fermi level, the resistivity measurement over 300 to 10K for both phases showed metallic behavior. (C) 2015 AIP Publishing LLC.
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| 8. |
- Azina, Clio, et al.
(författare)
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Deposition of MAX phase-containing thin films from a (Ti,Zr)(2)AlC compound target
- 2021
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Ingår i: Applied Surface Science. - : Elsevier. - 0169-4332 .- 1873-5584. ; 551
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Tidskriftsartikel (refereegranskat)abstract
- This work reports on sputter depositions carried out from a compound (Ti,Zr)(2)AlC target on Al2O3(0 0 0 1) substrates at temperatures ranging between 500 and 900 degrees C. Short deposition times yielded 30-40 nm-thick Al-containing (Ti,Zr)C films, whereas longer depositions yielded thicker films up to 90 nm which contained (Ti,Zr)C and intermetallics. At 900 degrees C, the longer depositions led to films that also consisted of solid solution MAX phases. Detailed transmission electron microscopy showed that both (Ti,Zr)(2)AlC and (Ti,Zr)(3)AlC2 solid solution MAX phases were formed. Moreover, this work discusses the growth mechanism of the thicker films, which started with the formation of the mixed (Ti,Zr)C carbide, followed by the nucleation and growth of aluminides, eventually leading to solid state diffusion of Al within the carbide, at the highest temperature (900 degrees C) to form the MAX phases.
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| 9. |
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| 10. |
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| 11. |
- Berndt, Sonja I., et al.
(författare)
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Genome-wide meta-analysis identifies 11 new loci for anthropometric traits and provides insights into genetic architecture
- 2013
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 45:5, s. 501-U69
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Tidskriftsartikel (refereegranskat)abstract
- Approaches exploiting trait distribution extremes may be used to identify loci associated with common traits, but it is unknown whether these loci are generalizable to the broader population. In a genome-wide search for loci associated with the upper versus the lower 5th percentiles of body mass index, height and waist-to-hip ratio, as well as clinical classes of obesity, including up to 263,407 individuals of European ancestry, we identified 4 new loci (IGFBP4, H6PD, RSRC1 and PPP2R2A) influencing height detected in the distribution tails and 7 new loci (HNF4G, RPTOR, GNAT2, MRPS33P4, ADCY9, HS6ST3 and ZZZ3) for clinical classes of obesity. Further, we find a large overlap in genetic structure and the distribution of variants between traits based on extremes and the general population and little etiological heterogeneity between obesity subgroups.
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| 12. |
- Bousquet, Jean, et al.
(författare)
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Allergic Rhinitis and its Impact on Asthma (ARIA) Phase 4 (2018) : Change management in allergic rhinitis and asthma multimorbidity using mobile technology
- 2019
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Ingår i: Journal of Allergy and Clinical Immunology. - : Elsevier. - 0091-6749 .- 1097-6825. ; 143:3, s. 864-879
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Tidskriftsartikel (refereegranskat)abstract
- Allergic Rhinitis and its Impact on Asthma (ARIA) has evolved from a guideline by using the best approach to integrated care pathways using mobile technology in patients with allergic rhinitis (AR) and asthma multimorbidity. The proposed next phase of ARIA is change management, with the aim of providing an active and healthy life to patients with rhinitis and to those with asthma multimorbidity across the lifecycle irrespective of their sex or socioeconomic status to reduce health and social inequities incurred by the disease. ARIA has followed the 8-step model of Kotter to assess and implement the effect of rhinitis on asthma multimorbidity and to propose multimorbid guidelines. A second change management strategy is proposed by ARIA Phase 4 to increase self-medication and shared decision making in rhinitis and asthma multimorbidity. An innovation of ARIA has been the development and validation of information technology evidence-based tools (Mobile Airways Sentinel Network [MASK]) that can inform patient decisions on the basis of a self-care plan proposed by the health care professional.
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| 13. |
- Bzhalava, Davit, et al.
(författare)
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Unbiased Approach for Virus Detection in Skin Lesions
- 2013
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Ingår i: PLOS ONE. - : Public Library of Science. - 1932-6203. ; 8:6
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Tidskriftsartikel (refereegranskat)abstract
- To assess presence of virus DNA in skin lesions, swab samples from 82 squamous cell carcinomas of the skin (SCCs), 60 actinic keratoses (AKs), paraffin-embedded biopsies from 28 SCCs and 72 kerathoacanthomas (KAs) and fresh-frozen biopsies from 92 KAs, 85 SCCs and 92 AKs were analyzed by high throughput sequencing (HTS) using 454 or Ion Torrent technology. We found total of 4,284 viral reads, out of which 4,168 were Human Papillomavirus (HPV)-related, belonging to 15 known (HPV8, HPV12, HPV20, HPV36, HPV38, HPV45, HPV57, HPV59, HPV104, HPV105, HPV107, HPV109, HPV124, HPV138, HPV147), four previously described putative (HPV 915 F 06 007 FD1, FA73, FA101, SE42) and two putatively new HPV types (SE46, SE47). SE42 was cloned, sequenced, designated as HPV155 and found to have 76% similarity to the most closely related known HPV type. In conclusion, an unbiased approach for viral DNA detection in skin tumors has found that, although some new putative HPVs were found, known HPV types constituted most of the viral DNA.
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| 14. |
- Claesson, Lisbeth, 1955, et al.
(författare)
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Comparison of visual acuity charts identifying visual impairment among older people outside the eye clinic
- 2013
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Ingår i: Disability and Rehabilitation. - : Informa UK Limited. - 0963-8288 .- 1464-5165. ; 35:16, s. 1394-1400
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: Evaluate the construct validity and describe sensitivity, specificity and predictive value of two short charts of visual acuity (VA) and examine whether these can identify and detect signs of visual impairment among older people. Method: The study included 43 persons, >65 years, with age related eye disease, living in their own homes. An ophthalmologist assessed the individuals' VA at an eye clinic with the 5 m KM chart. A research assistant assessed individuals' VA by the 1 m KM chart and the Visual Acuity Screening Test in their home environment. Results: All persons with a VA level of <0.5 were correctly identified by both instruments. The instruments have good positive and negative predictive values for the 1 m KM chart (73% and 100%) and for the Visual Acuity Screening Test (69% and 100%). The construct validity between the instruments was good, but the assessment at the eye clinic assessed the participants as having higher VA level. Conclusions: Both instruments have good construct validity, considering they were carried out in poorer lighting conditions and a good predictive value for screening out VA levels <0.5. The 1 m KM chart showed the best agreement with the 5 m KM chart.
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| 15. |
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| 16. |
- Conti, David, V, et al.
(författare)
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Trans-ancestry genome-wide association meta-analysis of prostate cancer identifies new susceptibility loci and informs genetic risk prediction
- 2021
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Ingår i: Nature Genetics. - : Springer Nature. - 1061-4036 .- 1546-1718. ; 53:1, s. 65-75
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Tidskriftsartikel (refereegranskat)abstract
- Prostate cancer is a highly heritable disease with large disparities in incidence rates across ancestry populations. We conducted a multiancestry meta-analysis of prostate cancer genome-wide association studies (107,247 cases and 127,006 controls) and identified 86 new genetic risk variants independently associated with prostate cancer risk, bringing the total to 269 known risk variants. The top genetic risk score (GRS) decile was associated with odds ratios that ranged from 5.06 (95% confidence interval (CI), 4.84-5.29) for men of European ancestry to 3.74 (95% CI, 3.36-4.17) for men of African ancestry. Men of African ancestry were estimated to have a mean GRS that was 2.18-times higher (95% CI, 2.14-2.22), and men of East Asian ancestry 0.73-times lower (95% CI, 0.71-0.76), than men of European ancestry. These findings support the role of germline variation contributing to population differences in prostate cancer risk, with the GRS offering an approach for personalized risk prediction. A meta-analysis of genome-wide association studies across different populations highlights new risk loci and provides a genetic risk score that can stratify prostate cancer risk across ancestries.
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| 17. |
- Eklund, Arne, 1957-, et al.
(författare)
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Short-term results of a randomized clinical trial comparing Lichtenstein open repair with totally extraperitoneal laparoscopic inguinal hernia repair
- 2006
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Ingår i: British Journal of Surgery. - : Oxford University Press (OUP). - 0007-1323 .- 1365-2168. ; 93:9, s. 1060-1068
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Tidskriftsartikel (refereegranskat)abstract
- Background: Laparoscopic herniorrhaphy has emerged as a recognized operative method for inguinal hernia repair. This study compared the short-term results of two tension-free methods of repair: totally extraperitoneal (TEP) laparoscopic patch repair and the open Lichtenstein mesh technique. Methods: A total of 1513 men from 11 hospitals who presented with a primary unilateral inguinal hernia were randomized to one of the two methods. Operating time, short-term complications, reoperations, postoperative pain, consumption of analgesics, sick leave and time to resumption of normal physical activities were recorded. Results: Some 1371 of the 1513 men underwent surgery, 665 in the TEP group and 706 in the Lichtenstein group. The median duration of operation was 55 min for both procedures and 91.0 per cent of die patients in both groups were discharged on the day of operation. Patients in the TEP group experienced less postoperative pain (P < 0.001), consumed fewer analgesics (P < 0.001), had a shorter period of sick leave (7 versus 12 days; P < 0.001) and a shorter time to resumption of normal physical activity (20 versus 31 days; P < 0.001). Conclusion: The TEP technique took no longer to perform, and was associated with less postoperative pain, a shorter period of sick leave and a faster recovery, compared with open Lichtenstein hernia repair.
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| 18. |
- Eklund, Elisabeth, 1988-, et al.
(författare)
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Perceived articulatory precision in patients with Parkinson’s disease after deep brain stimulation of subthalamic nucleus and caudal zona incerta
- 2015
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Ingår i: Clinical Linguistics & Phonetics. - : Informa UK Limited. - 0269-9206 .- 1464-5076. ; 29:2, s. 150-166
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Tidskriftsartikel (refereegranskat)abstract
- The effect of deep brain stimulation (DBS) of the subthalamic nucleus (STN) and caudal zona incerta (cZi) on speech articulation in patients with Parkinson’s disease (PD) was investigated. Read speech samples were collected from nine patients with STN-DBS and ten with cZi-DBS. The recordings were made preoperatively and 12 months postoperatively with stimulator on and off (on medication). Blinded, randomized, repeated perceptual assessments were performed on words and isolated fricatives extracted from the recordings to assess 1) overall articulatory quality ratings, 2) frequency of occurrence of misarticulation patterns, and 3) fricative production. Statistically significant worsening of articulatory measures on- compared with off-stimulation occurred in the cZi-DBS group, with deteriorated articulatory precision ratings, increased presence of misarticulations (predominately altered realizations of plosives and fricatives) and a reduced accuracy in fricative production. A similar, but not significant, trend was found for the STN-DBS group.
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| 19. |
- Eklund, Elin, 1992, et al.
(författare)
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Quasi-experimental evaluation of municipal ice cleat distribution programmes for older adults in Sweden
- 2023
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Ingår i: Injury Prevention. - : BMJ Publishing Group Ltd. - 1353-8047 .- 1475-5785. ; 29:5, s. 378-83
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Tidskriftsartikel (refereegranskat)abstract
- IntroductionFall injuries caused by icy road conditions are a prevalent public health problem during winters in Sweden, especially in older populations. To combat this problem, many Swedish municipalities have distributed ice cleats to older adults. While previous research has shown promising results, there is a lack of comprehensive empirical data on the effectiveness of ice cleat distribution. We address this gap by investigating the impact of these distribution programmes on ice-related fall injuries among older adults. MethodsWe combined survey data on ice cleat distribution in Swedish municipalities with injury data from the Swedish National Patient Register (NPR). The survey was used to identify municipalities that have distributed ice cleats to older adults at some point between 2001 and 2019. Data from NPR were used to identify municipality-level data on patients who have been treated for injuries related to snow and ice. We used a triple differences design-a generalisation of difference in differences-that compared ice-related fall injury rates before and after intervention in 73 treatment and 200 control municipalities, with unexposed age groups serving as within-municipality controls. ResultsWe estimate that the average ice cleat distribution programmes reduced ice-related fall injury rates by -0.24 (95% CI -0.49 to 0.02) per 1000 person-winters. The impact estimate was larger in municipalities that distributed more ice cleats (-0.38 (95% CI -0.76 to -0.09)). No similar patterns were found for fall injuries unrelated to snow and ice. ConclusionOur results suggest that ice cleat distribution can decrease the incidence of ice-related injuries among older adults.
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| 20. |
- Eklund, Johan, 1977-, et al.
(författare)
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Inherited Corporate Control and Returns on Investment
- 2013
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Ingår i: Small Business Economics. - : Springer Science and Business Media LLC. - 0921-898X .- 1573-0913. ; 41:2, s. 419-431
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Tidskriftsartikel (refereegranskat)abstract
- This paper contributes to the literature on management in family firms by investigating how succession in family firms affects returns on investment. The identities of the chief executive officer (CEO) and the chairman of the board (COB) were used to establish whether the management of the firm can be characterized as founder, descendant, or external management. A unique, unbalanced panel data set on listed Swedish firms covering the period from 1990 to 2005 was used in the analysis. The results show that founder management has a positive effect on the returns on investment in family firms, whereas descendant management has a negative impact. An external CEO as a successor in family firms leads to more efficient investment policies with increased firm value as a result. That is, when studying corporate governance in family firms it is important to account for what type of management the firm has. Further studies are required to understand the relationship between ownership, control, management, and firm performance.
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| 21. |
- Eklund, Nicolina, et al.
(författare)
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EQUINE SCIENCE USING BETA CAE SOFTWARE
- 2017
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Ingår i: 7 th BEFORE REALITY CONFERENCE.
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Konferensbidrag (refereegranskat)abstract
- The equestrian world is evolving and the interest for more ergonomic and durable equipment is growing. To fulfil this need, methods to validate, improve and design new equipment is crucial. The purpose of this project was to develop such a method, by the use of software from BETA CAE Systems. The target was to study the effects exerted by the bridle on the neck of a horse, as a starting point for developing the method. A simplified 3D (Computer Aided Engineering) CAE model of a horse neck was generated by using RETOMO-tool for segmentation of medical CTscan images. The model was pre-processed and prepared for the solver Abaqus by built-in functions in ANSA. META post-processor was used to examine the results of the simulations, showing how stress spreads around the neck by identifying areas with higher and lower stress concentrations. The outcome of the simulations provides a numerical evaluation for understanding mechanical effects on the neck of the horse, exerted by the bridle.
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| 22. |
- Eklund, Per, et al.
(författare)
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Discovery of the Ternary Nanolaminated Compound Nb2GeC by a Systematic Theoretical-Experimental Approach
- 2012
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Ingår i: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 109:3, s. 035502-
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Tidskriftsartikel (refereegranskat)abstract
- Since the advent of theoretical materials science some 60 years ago, there has been a drive to predict and design new materials in silicio. Mathematical optimization procedures to determine phase stability can be generally applicable to complex ternary or higher-order materials systems where the phase diagrams of the binary constituents are sufficiently known. Here, we employ a simplex-optimization procedure to predict new compounds in the ternary Nb-Ge-C system. Our theoretical results show that the hypothetical Nb2GeC is stable, and excludes all reasonably conceivable competing hypothetical phases. We verify the existence of the Nb2GeC phase by thin film synthesis using magnetron sputtering. This hexagonal nanolaminated phase has a and c lattice parameters of similar to 3.24 angstrom and 12.82 angstrom.
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| 23. |
- Eklund, Per, et al.
(författare)
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Layered ternary M(n+1)AX(n) phases and their 2D derivative MXene: an overview from a thin-film perspective
- 2017
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Ingår i: Journal of Physics D. - : IOP PUBLISHING LTD. - 0022-3727 .- 1361-6463. ; 50:11
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Forskningsöversikt (refereegranskat)abstract
- Inherently and artificially layered materials are commonly investigated both for fundamental scientific purposes and for technological application. When a layered material is thinned or delaminated to its physical limits, a two-dimensional (2D) material is formed and exhibits novel properties compared to its bulk parent phase. The complex layered phases known as MAX phases (where M = early transition metal, A = A-group element, e.g. Al or Si, and X = C or N) are an exciting model system for materials design and the understanding of process-structure-property relationships. When the A layers are selectively etched from the MAX phases, a new type of 2D material is formed, named MXene to emphasize the relation to the MAX phases and the parallel with graphene. Since their discovery in 2011, MXenes have rapidly become established as a novel class of 2D materials with remarkable possibilities for composition variations and property tuning. This article gives a brief overview of MAX phases and MXene from a thin-film perspective, reviewing theory, characterization by electron microscopy, properties and how these are affected by the change in dimensionality, and outstanding challenges.
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| 24. |
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| 25. |
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| 26. |
- Eriksson, Anders, et al.
(författare)
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Nanocolumnar Epitaxial Ti1-xSixN (0 ≤ x ≤ 0.18) Thin Films Grown by Dual Reactive Magnetron Sputtering on MgO (001), (011), and (111) Substrates
- 2012
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Ti1-xSixNy thin films and multilayers have been grown on single-crystal TiN-templated MgO (001), (011), and (111) substrates kept at 550 °C. Elemental Ti and Si targets were used in UVH reactive dual magnetron sputtering in a mixed Ar/N2 discharge. Composition analysis by time-of-flight energy elastic recoil detection analysis show that the films are close to stoichiometric (0.95 ≤ y ≤ 1.00) with respect to TiN over the wide range of Si concentrations 0 ≤ x ≤ 0.22. High-resolution transmission electron microscopy (TEM) combined with scanning TEM and energy dispersive Xray analysis show that all films grow epitaxially for x ≤ 0.18 and that as much as every fifth Ti atom can be replaced by Si (~10 at.%) in Ti1-xSixN(001). For the (011) and (111)-oriented films, however, only 1-2 at.% Si substitutes for Ti. Instead, Si segregates to form crystalline-to-amorphous SiNz (z ≈ 1) tissue phases, which promote the formation of epitaxial TiN nanocolumns. The nanocolumns have preferred {110} interfaces and {200} top facets and grow several hundreds of nm in length.
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| 27. |
- Eriksson, Anders, et al.
(författare)
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Si incorporation in Ti1-xSixN films grown on TiN(001) and (001)-faceted TiN(111) columns
- 2014
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Ingår i: Surface & Coatings Technology. - : Elsevier. - 0257-8972 .- 1879-3347. ; 257, s. 121-128
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Tidskriftsartikel (refereegranskat)abstract
- Thin films consisting of TiN nanocrystallites encapsulated in a fully percolated SiNy tissue phase are archetypes for hard and superhard nanocomposites. Here, we investigate metastable SiNy solid solubility in TiN and probe the effects of surface segregation during the growth of TiSiN films onto substrates that are either flat TiN(001)/MgO(001) epitaxial buffer layers or TiN(001) facets of length 1-5 nm terminating epitaxial TiN(111) nanocolumns, separated by voids, deposited on epitaxial TiN(111)/MgO(111) buffer layers. Using reactive magnetron sputter deposition, the TiSiN layers were grown at 550 degrees C and the TiN buffer layers at 900 degrees C On TiN(001), the films are NaCl-structure single-phase metastable Ti1-xSixN(001) with N/(Ti + Si) = 1 and 0 less than= x less than= 0.19. These alloys remain single-crystalline to critical thicknesses h(c) ranging from 100 +/- 30 nm with x = 0.13 to 40 +/- 10 nm with x = 0.19. At thicknesses h greater than h(c), the epitaxial growth front breaks down locally to form V-shaped polycrystalline columns with an underdense feather-like nanostructure. In contrast, the voided epitaxial TiN(111) columnar surfaces, as well as the TiN(001) facets, act as sinks for SiNy. For Ti1-xSixN layers with global average composition values less than x greater than = 0.16, the local x value in the middle of Ti1-xSixN columns increases from 0.08 for columns with radius r similar or equal to 2 nm to x = 0.14 with r similar or equal to 4 nm. The average out-of-plane lattice parameter of epitaxial nanocolumns encapsulated in SiNy decreases monotonically with increasing Si fraction less than x greater than, indicating the formation of metastable (Ti,Si)N solid solutions under growth conditions similar to those of superhard nanocomposites for which the faceted surfaces of nanograins also provide sinks for SiNy.
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| 28. |
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| 29. |
- Fashandi, Hossein, et al.
(författare)
-
Synthesis of Ti3AuC2, Ti3Au2C2 and Ti3IrC2 by noble metal substitution reaction in Ti3SiC2 for high-temperature-stable Ohmic contacts to SiC
- 2017
-
Ingår i: Nature Materials. - : NATURE PUBLISHING GROUP. - 1476-1122 .- 1476-4660. ; 16:8, s. 814-818
-
Tidskriftsartikel (refereegranskat)abstract
- The large class of layered ceramics encompasses both van der Waals (vdW) and non-vdW solids. While intercalation of noble metals in vdW solids is known, formation of compounds by incorporation of noble-metal layers in non-vdW layered solids is largely unexplored. Here, we show formation of Ti3AuC2 and Ti3Au2C2 phases with up to 31% lattice swelling by a substitutional solid-state reaction of Au into Ti3SiC2 single-crystal thin films with simultaneous out-diffusion of Si. Ti3IrC2 is subsequently produced by a substitution reaction of Ir for Au in Ti3Au2C2. These phases form Ohmic electrical contacts to SiC and remain stable after 1,000 h of ageing at 600 degrees C in air. The present results, by combined analytical electron microscopy and ab initio calculations, open avenues for processing of noble-metal-containing layered ceramics that have not been synthesized from elemental sources, along with tunable properties such as stable electrical contacts for high-temperature power electronics or gas sensors.
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| 30. |
- Fashandi, Hossein, et al.
(författare)
-
Ti2Au2C and Ti3Au2C2 formed by solid state reaction of gold with Ti2AlC and Ti3AlC2
- 2017
-
Ingår i: Chemical Communications. - : Royal Society of Chemistry. - 1359-7345 .- 1364-548X. ; 53:69, s. 9554-9557
-
Tidskriftsartikel (refereegranskat)abstract
- Incorporation of layers of noble metals in non-van der Waals layered materials may be used to form novel layered compounds. Recently, we demonstrated a high-temperature-induced exchange process of Au with Si in the layered phase Ti3SiC2, resulting in the formation of Ti3AuC2 and Ti3Au2C2. Here, we generalize this technique showing that Au/Ti2AlC and Au/Ti3AlC2 undergo an exchange reaction at 650 [degree]C to form Ti2Au2C and Ti3Au2C2 and determine their structures by electron microscopy, X-ray diffraction, and ab initio calculations. These results imply that noble-metal-containing layered phases should be possible to synthesize in many systems. The metal to be introduced should be inert to the transition-metal carbide layers, and exhibit negative heat of mixing with the initial A element in a liquid phase or two-phase liquid/solid region at the annealing temperature.
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| 31. |
- Fritz, Johanna, et al.
(författare)
-
Determinants of Implementing an Information and Communication Technology Tool for Social Interaction Among Older People : Qualitative Content Analysis of Social Services Personnel Perspectives
- 2024
-
Ingår i: JMIR Aging. - : JMIR Publications Inc.. - 2561-7605. ; 7:1
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Older people are particularly vulnerable to social isolation and loneliness, which can lead to ill-health, both mentally and physically. Information and communication technology (ICT) can supplement health and social care and improve health among the vulnerable, older adult population. When ICT is used specifically for communication with others, it is associated with reduced loneliness in older populations. Research is sparse on how the implementation of ICT, used specifically for communication among older people in social services, can be performed. It is recommended to consider the determinants of implementation, that is, barriers to and facilitators of implementation. Determinants related to older people using ICT tools are reported in several studies. To the best of our knowledge, studies investigating the determinants related to the social services perspective are lacking. Objective: This study aims to explore the determinants of implementing the Fik@ room, a new, co-designed, and research-based ICT tool for social interaction among older people, from a social services personnel perspective. Methods: This study used an exploratory, qualitative design. An ICT tool called the Fik@ room was tested in an intervention study conducted in 2021 in 2 medium-sized municipalities in Sweden. Informants in this study were municipal social services personnel with experience of implementing this specific ICT tool in social services. We conducted a participatory workshop consisting of 2 parts, with 9 informants divided into 2 groups. We analyzed the data using qualitative content analysis with an inductive approach. Results: The results included 7 categories of determinants for implementing the ICT tool. Being able to introduce the ICT tool in an appropriate manner concerns the personnel’s options for introducing and supporting the ICT tool, including their competencies in using digital equipment. Organizational structure concerns a structure for communication within the organization. Leadership concerns engagement and enthusiasm as driving forces for implementation. The digital maturity of the social services personnel concerns the personnel’s skills and attitudes toward using digital equipment. Resources concern time and money. IT support concerns accessibility, and legal liability concerns possibilities to fulfill legal responsibilities. Conclusions: The results show that implementation involves an entire organization at varying degrees. Regardless of how much each level within the organization comes into direct contact with the ICT tool, all levels need to be involved to create the necessary conditions for successful implementation. The prerequisites for the implementation of an ICT tool will probably change depending on the digital maturity of future generations. As this study only included 9 informants, the results should be handled with care. The study was performed during the COVID-19 pandemic, which has probably affected the results.
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| 32. |
- Gau, Rémi, et al.
(författare)
-
Brainhack : Developing a culture of open, inclusive, community-driven neuroscience
- 2021
-
Ingår i: Neuron. - : Elsevier. - 0896-6273 .- 1097-4199. ; 109:11, s. 1769-1775
-
Tidskriftsartikel (refereegranskat)abstract
- Brainhack is an innovative meeting format that promotes scientific collaboration and education in an open, inclusive environment. This NeuroView describes the myriad benefits for participants and the research community and how Brainhacks complement conventional formats to augment scientific progress.
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| 33. |
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| 34. |
- Gudjonsdottir, Johanna, et al.
(författare)
-
Psychometric evaluation of the Swedish Quality of Dyadic Relationships scale : homogeneity and construct validity
- 2021
-
Ingår i: Scandinavian Journal of Caring Sciences. - : Blackwell Publishing. - 0283-9318 .- 1471-6712. ; 35:2, s. 468-475
-
Tidskriftsartikel (refereegranskat)abstract
- Rationale and aims: The Quality of Dyadic Relationships is a self-assessment scale used to evaluate various aspects of relationship quality. Psychometric evaluation by the developers of the instrument has led to a nontested amended version. Further psychometric testing is thus warranted, and the aim of this study was to evaluate homogeneity, construct validity (in terms of concurrent, discriminant and known-groups validity) and any floor and ceiling effects of the Quality of Dyadic Relationships.Methods: Forty-seven cohabitant couples (47 women with a mean age of 30.0 years and 47 men with a mean age of 31.5 years) answered the Quality of Dyadic Relationships, the Relationship Assessment Scale (to test concurrent validity) and the Perceived Stress Scale (to test discriminant validity). Homogeneity (internal consistency) was calculated by Cronbach's alpha. Concurrent and discriminant validity were estimated as correlations between Quality of Dyadic Relationships and the other instruments. Assessment of known-groups validity was based on the variables of parental status and gender. Floor and ceiling effects were evaluated according to frequency distribution.Results: The overall homogeneity was good with acceptable Cronbach's alpha values (alpha > 0.70) for all subscales but dyadic sexuality. Concurrent validity and discriminant validity were found. Known-groups validity was indicated by significant differences between individuals with different parental status on the total QDR index, where the ones without children scored higher. No difference between the genders was found. No significant floor effects were found, but a significant ceiling effect was found in the subscale dyadic sensuality, with 27.7% of respondents scoring maximum.Conclusion: In all, the QDR showed promising psychometric properties and may be used for screening and follow-up purposes. However, it can benefit from further development, as suggested by the ceiling effect in the subscale dyadic sensuality and the low internal consistency in the subscale dyadic sexuality.
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| 35. |
- Gusdal, Annelie K, 1963-, et al.
(författare)
-
Older Adults’ Use of a Research-Based Web Platform for Social Interaction
- 2023
-
Ingår i: Healthcare. - : MDPI AG. - 2227-9032. ; 11:3
-
Tidskriftsartikel (refereegranskat)abstract
- Loneliness and social isolation are triggers for unfavorable changes in older adults’ health and well-being. Information and communication technology (ICT) can be used by older adults to mitigate the negative effects of loneliness and social isolation. However, ICT needs to be customized to the specific needs and conditions of older adults. The aim of this study was to explore older adults’ use of a new, co-designed and research-based web platform for social interaction from the perspectives of older adults, researchers, and social services personnel. The study is an intervention study with a multimethod approach in which 20 older adults used the web platform for social interaction “the Fik@ room” for eight weeks. Quantitative and qualitative data were collected pretest, during the test, and posttest. The Fik@ room met the expectations of those older adults who completed the study. It enabled them to expand their social network and develop new friendships, but their experiences of loneliness were not reduced. The involvement of social services personnel in recruitment and support was important in facilitating older adults’ use of the Fik@ room. Our study contributes knowledge about a new, co-designed and research-based web platform, customized specifically for older adults, which is valuable in guiding the design and delivery of future web platforms for social interaction among older adults.
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| 36. |
- Halim, Joseph, et al.
(författare)
-
Electronic and optical characterization of 2D Ti2C and Nb2C (MXene) thin films
- 2019
-
Ingår i: Journal of Physics. - : IOP PUBLISHING LTD. - 0953-8984 .- 1361-648X. ; 31:16
-
Tidskriftsartikel (refereegranskat)abstract
- Two-dimensional (2D) transition metal carbides and/or nitrides (MXenes) are a new class of 2D materials, with extensive opportunities for property tailoring due to the numerous possibilities for varying chemistries and surface terminations. Here, Ti2AlC and Nb2AlC MAX phase epitaxial thin films were deposited on sapphire substrates by physical vapor deposition. The films were then etched in LiF/HCl solutions, yielding Li-intercalated, 2D Ti2CTz and Nb2CTz films, whose terminations, transport and optical properties were characterized. The former exhibits metallic conductivity, with weak localization below 50 K. In contrast, the Nb-based film exhibits an increase in resistivity with decreasing temperature from RT down to 40K consistent with variable range hopping transport. The optical properties of both films were determined from spectroscopic ellipsometry in the 0.75 to 3.50 eV range. The results for Ti2Clz films confirm the metallic behavior. In contrast, no evidence of metallic behavior is observed for the Nb2CT(z) film. The present work therefore demonstrates that one fruitful approach to alter the electronic and optical properties of MXenes is to change the nature of the transition metal.
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| 37. |
- Halim, Joseph, et al.
(författare)
-
Sodium hydroxide and vacuum annealing modifications of the surface terminations of a Ti3C2 (MXene) epitaxial thin film
- 2018
-
Ingår i: RSC Advances. - : ROYAL SOC CHEMISTRY. - 2046-2069. ; 8:64, s. 36785-36790
-
Tidskriftsartikel (refereegranskat)abstract
- We investigate, and quantify, changes in structure and surface terminations of epitaxial thin films of titanium carbide (Ti3C2) MXene, when treated by sodium hydroxide solution followed by vacuum annealing at 550 degrees C. Using X-ray photoelectron spectroscopy and scanning transmission electron microscopy, we show that NaOH treatment produce an increase in the c-lattice parameter together with an increase in the O terminations and a decrease in the F terminations. There is also an increase in the percentage of the binding energy of Ti-species in Ti 2p XPS region, which suggests an increase in the overall oxidation state of Ti. After subsequent annealing, the c-lattice parameter is slightly reduced, the overall oxidation state of Ti is decreased, and the F surface terminations are further diminished, leaving a surface with predominantly O as the surface terminating species. It is important to note that NaOH treatment facilitates removal of F at lower annealing temperatures than previously reported, which in turn is important for the range of attainable properties.
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| 38. |
- Halim, Joseph, 1985-
(författare)
-
Synthesis and Characterization of 2D Nanocrystals and Thin Films of Transition Metal Carbides (MXenes)
- 2014
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Two dimensional (2D) materials have received growing interest because of their unique properties compared to their bulk counterparts. Graphene is the archetype 2D solid, but other materials beyond graphene, such as MoS2 and BN have become potential candidates for several applications. Recently, a new family of 2D materials of early transition metal carbides and carbonitrides (Ti2CTx, Ti3C2Tx, Ti3CNTx, Ta4C3Tx, and more), labelled MXenes, has been discovered, where T stands for the surface-terminating groups.Before the present work, MXenes had only been synthesized in the form of exfoliated and delaminated powders, which is not suitable for electronic applications. In this thesis, I demonstrate the synthesis of MXenes as epitaxial thin films, a more suitable form for electronic and photonic applications. Results show that 2D epitaxial Ti3C2Tx films - produced by HF and NH4HF2 etching of magnetron sputter-grown Ti3AlC2 - exhibit metallic conductive behaviour down to 100 K and are 90% transparent to light in the visible-infrared range. The results from this work may open the door for MXenes as potential candidates for transparent conductive electrodes as well as in electronic, photonic and sensing applications.MXenes have been shown to intercalate cations and molecules between their layers that in turn can alter the surface termination groups. There is therefore a need to study the surface chemistries of synthetized MXenes to be able to study the effect of intercalation as well as altering the surface termination groups on the electronic structure and chemical states of the elements present in MXene layers. X-ray Photoelectron Spectroscopy (XPS) in-depth characterization was used to investigate surface chemistries of Ti3C2Tx and Ti2CTx. This thesis includes the discussion of the effect of Ar+ sputtering and the number of layers on the surface chemistry of MXenes. This study serves as a baseline for chemical modification and tailoring of the surface chemistry groups to potential uses and applications.New MXene phases, Nb2CTx and V2CTx, are shown in this thesis to be produced from HF chemical etching of Nb2AlC and V2AlC powders. Characterization of the produced MXenes was carried out using Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), Transmission Electron Microscope (TEM) and XPS. Nb2CTx and V2CTx showed promising performance as electrodes for Li-ion batteries.In this thesis, electrochemical etching was used in an attempt to produce 2D metal carbides (MXene) from their ternary metal carbides, Ti3SiC2, Ti3AlC2 and Ti2AlC MAX phases. MAX phases in the form of highly dense bulk produced by Hot Isostatic Press. Several etching solutions were used such as HF, NaCl and HCl. Unlike the HF chemical etching of MAX phases, which results in MXenes, the electrochemical etching resulted in Carbide Derived Carbon (CDC). Here, I show the characterization of the produced CDC using several techniques such as XRD, TEM, Raman spectroscopy, and XPS. Electrochemical characterization was performed in the form of cyclic voltammetry, which sheds light on the etching mechanism.
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| 39. |
- Halim, Joseph, 1985-
(författare)
-
Synthesis and transport properties of 2D transition metal carbides (MXenes)
- 2018
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Since the isolation and characterization of graphene, there has been a growing interest in 2D materials owing to their unique properties compared to their 3D counterparts. Recently, a family of 2D materials of early transition metal carbides and nitrides, labelled MXenes, has been discovered (Ti2CTz, Ti3C2Tz, Mo2TiC2Tz, Ti3CNTz, Ta4C3Tz, Ti4N3Tz among many others), where T stands for surface-terminating groups (O, OH, and F). MXenes are mostly produced by selectively etching A layers (where A stands for group A elements, mostly groups 13 and 14) from the MAX phases. The latter are a family of layered ternary carbides and/or nitrides and have a general formula of Mn+1AXn (n = 1-3), where M is a transition metal and X is carbon and/or nitrogen. The produced MXenes have a conductive carbide core and a non-conductive O-, OH- and/or F-terminated surface, which allows them to work as electrodes for energy storage applications, such as Li-ion batteries and supercapacitors.Prior to this work, MXenes were produced in the form of flakes of lateral dimension of about 1 to 2 microns; such dimensions and form are not suitable for electronic characterization and applications. I have synthesized various MXenes (Ti3C2Tz, Ti2CTz and Nb2CTz) as epitaxial thin films, a more suitable form for electronic and photonic applications. These films were produced by HF, NH4HF2 or LiF + HCl etching of magnetron sputtered epitaxial Ti3AlC2, Ti2AlC, and Nb2AlC thin films. For transport properties of the Ti-based MXenes, Ti2CTz and Ti3C2Tz, changing n from 1 to 2 resulted in an increase in conductivity but had no effect on the transport mechanism (i.e. both Ti3C2Tx and Ti2CTx were metallic). In order to examine whether the electronic properties of MXenes differ when going from a few layers to a single flake, similar to graphene, the electrical characterization of a single Ti3C2Tz flake with a lateral size of about 10 μm was performed. These measurements, the first for MXene, demonstrated its metallic nature, along with determining the nature of the charge carriers and their mobility. This indicates that Ti3C2Tz is inherently of 2D nature independent of the number of stacked layers, unlike graphene, where the electronic properties change based on the number of stacked layers.Changing the transition metal from Ti to Nb, viz. comparing Ti2CTz and Nb2CTz thin films, the electronic properties and electronic conduction mechanism differ. Ti2CTz showed metallic-like behavior (resistivity increases with increasing temperature) unlike Nb2CTz where the conduction occurs via variable range hopping mechanism (VRH) - where resistivity decreases with increasing temperature.Furthermore, these studies show the synthesis of pure Mo2CTz in the form of single flakes and freestanding films made by filtering Mo2CTz colloidal suspensions. Electronic characterization of free-standing films made from delaminated Mo2CTz flakes was investigated, showing that a VRH mechanism prevails at low temperatures (7 to ≈ 60 K). Upon vacuum annealing, the room temperature, RT, conductivity of Mo2CTx increased by two orders of magnitude. The conduction mechanism was concluded to be VRH most likely dominated by hopping within each flake.Other Mo-based MXenes, Mo2TiC2Tz and Mo2Ti2C3Tz, showed VRH mechanism at low temperature. However, at higher temperatures up to RT, the transport mechanism was not clearly understood. Therefore, a part of this thesis was dedicated to further investigating the transport properties of Mo-based MXenes. This includes Mo2CTz, out-of-plane ordered Mo2TiC2Tz and Mo2Ti2C3Tz, and vacancy ordered Mo1.33CTz. Magneto-transport of free-standing thin films of the Mo-based MXenes were studied, showing that all Mo-based MXenes have two transport regimes: a VRH mechanism at lower temperatures and a thermally activated process at higher temperatures. All Mo-based MXenes except Mo1.33CTz show that the electrical transport is dominated by inter-flake transfer. As for Mo1.33CTz, the primary electrical transport mechanism is more likely to be intra-flake.The synthesis of vacancy ordered MXenes (Mo1.33CTz and W1.33CTz) raised the question of possible introduction of vacancies in all MXenes. Vacancy ordered MXenes are produced by selective etching of Al and (Sc or Y) atoms from the parent 3D MAX phases, such as (Mo2/3Sc1/3)2AlC, with in-plane chemical ordering of Mo and Sc. However, not all quaternary parent MAX phases form the in-plane chemical ordering of the two M metals; thus the synthesis of the vacancy-ordered MXenes is restricted to a very limited number of MAX phases. I present a new method to obtain MXene flakes with disordered vacancies that may be generalized to all quaternary MAX phases. As proof of concept, I chose Nb-C MXene, as this 2D material has shown promise in several applications, including energy storage, photothermal cell ablation and photocatalysts for hydrogen evolution. Starting from synthetizing (Nb2/3Sc1/3)2AlC quaternary solid solution and etching both the Sc and Al atoms resulted in Nb1.33C material with a large number of vacancies and vacancy clusters. This method may be applicable to other quaternary or higher MAX phases wherein one of the transition metals is more reactive than the other, and it could be of vital importance in applications such as catalysis and energy storage.
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| 40. |
- Halim, Joseph, 1985-, et al.
(författare)
-
Synthesis of Two-Dimensional Nb1.33C (MXene) with Randomly Distributed Vacancies by Etching of the Quaternary Solid Solution (Nb2/3Sc1/3)2AlC MAX Phase
- 2018
-
Ingår i: ACS Applied Nano Materials. - : American Chemical Society (ACS). - 2574-0970. ; 1:6, s. 2455-2460
-
Tidskriftsartikel (refereegranskat)abstract
- Introducing point defects in two-dimensional (2D) materials can alter or enhance their properties. Here, we demonstrate how etching a laminated (Nb2/3Sc1/3)2AlC MAX phase (solid solution) of both the Sc and Al atoms results in a 2D Nb1.33C material (MXene) with a large number of vacancies and vacancy clusters. This method is applicable to any quaternary, or higher, MAX phase, wherein one of the transition metals is more reactive than the other and could be of vital importance in applications such as catalysis and energy storage. We also report, for the first time, on the existence of solid solution (Nb2/3Sc1/3)3AlC2 and (Nb2/3Sc1/3)4AlC3 phases.
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| 41. |
- Halim, Joseph, et al.
(författare)
-
Variable range hopping and thermally activated transport in molybdenum-based MXenes
- 2018
-
Ingår i: Physical Review B. - : AMER PHYSICAL SOC. - 2469-9950 .- 2469-9969. ; 98:10
-
Tidskriftsartikel (refereegranskat)abstract
- The magnetotransport of freestanding, vacuum filtered, thin films of Mo2CTz, Mo1.33CTz, Mo2TiC2Tz, and Mo2Ti2C3Tz was measured in the 10-300-K temperature (T) range. Some of the films were annealed before measuring their transport properties. Analysis of the results suggest that-with the exception of the heavily defective Mo1.33CTz composition-in the 10- to 200-K temperature regime, variable range hopping between individual MXene sheets is the operative conduction mechanism. For Mo1.33CTz it is more likely that variable range hopping within individual flakes is rate limiting. At higher temperatures, a thermally activated process emerges in all cases. It follows that improved fabrication processes should lead to considerable improvements in the electrical transport of Mo-based MXenes.
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| 42. |
- Halim, Joseph, et al.
(författare)
-
X-ray Photoelectron Spectroscopy Characterization of Two-Dimensional Titanium Metal Carbides (MXenes)
- 2014
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Herein, we report X-ray Photoelectron Spectroscopy (XPS) analysis for cold pressed exfoliated 2D nanocrystals of transition metal carbides, MXenes. MXenes are a recently discovered family of 2D materials produced by selective chemical etching of the A element from MAX phases which are ternary metal carbides and nitrides. The latter has the formula of Mn+1AXn, where M is an early transition metal, A is an A-group element, and X is C and/or N. This study is a comparison between two MXenes, Ti3C2Tx and Ti2CTx, where Tx stands for surface termination groups such as –O, –OH, and –F. Ti3C2Tx and Ti2CTx were prepared by immersion of Ti3AlC2 and Ti2AlC powders in 50% conc. HF. A thorough XPS analysis was performed through peak fitting of high resolution XPS spectra and valence band, VB, spectra analysis. The effect of Ar sputtering as well as the number of layers n was the primarily interest of this study. According to the peak fitting analysis, both phases contain the following species, Ti–C, C–C, Ti–F, Ti–O and Ti–OH resulting in the following chemical formulas: Ti3C2(OH)x(O)y(F)z and Ti2C(OH)x(O)y(F)z. Comparing the VB spectra with the DOS calculations show the valance band spectra is actually a mixture of MXene with various terminations of OH, O and F. Before Ar+ sputtering both phases show a large percentage of fluorinated-TiO2 which is due to MXene surface oxidation as well as CHx, C-O and COO groups arising from either surface contaminations or due to drying the etched powders in ethanol after washing the powder of the HF acid. According to the VB spectra, it is shown that the fluorinated TiO2 is actually a mixture of anatase and rutile. The number of layers, n, also plays a role; the lower n, the more the MXene is prone to oxidation.
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| 43. |
- Halim, Joseph, 1985-, et al.
(författare)
-
X-ray photoelectron spectroscopy of select multi-layered transition metal carbides (MXenes)
- 2016
-
Ingår i: Applied Surface Science. - : ELSEVIER SCIENCE BV. - 0169-4332 .- 1873-5584. ; 362, s. 406-417
-
Tidskriftsartikel (refereegranskat)abstract
- In this work, a detailed high resolution X-ray photoelectron spectroscopy (XPS) analysis is presented for select MXenes a recently discovered family of two-dimensional (2D) carbides and carbonitrides. Given their 2D nature, understanding their surface chemistry is paramount. Herein we identify and quantify the surface groups present before, and after, sputter-cleaning as well as freshly prepared vs. aged multi layered cold pressed discs. The nominal compositions of the MXenes studied here are Ti-3 C2Tx,Ti3CNTx, Nb2CTx and Nb4C3Tx where T represents surface groups that this work attempts to quantify. In all the cases, the presence of three surface terminations, O, OH and F, in addition to OH-terminations relatively strongly bonded to H2O molecules, was confirmed. From XPS peak fits, it was possible to establish the average sum of the negative charges of the terminations for the aforementioned MXenes. Based on this work, it is now possible to quantify the nature of the surface terminations. This information can, in turn, be used to better design and tailor these novel 2D materials for various applications. Published by Elsevier B.V.
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| 44. |
- Halim, Joseph, et al.
(författare)
-
XPS of cold pressed multilayered and freestanding delaminated 2D thin films of Mo2TiC2Tz and Mo2Ti2C3Tz (MXenes)
- 2019
-
Ingår i: Applied Surface Science. - : ELSEVIER. - 0169-4332 .- 1873-5584. ; 494, s. 1138-1147
-
Tidskriftsartikel (refereegranskat)abstract
- MXenes, transition metal carbides and/or nitrides, that are synthesized from the top down by etching of their 3D parent layered solids, the MAX phases, are the latest family of the two-dimensional solids discovered. When the A layers - mostly Al - are etched they are replaced by surface terminations, Tz mainly comprised of O-, OH- and F-terminations. One of the few techniques capable of quantifying these surface terminations is X-ray photo-electron spectroscopy, XPS. Herein, we undertook an XPS study of the out-of-plane ordered MXenes, Mo2TiC2Tz and Mo2Ti2C3Tz, in both multilayered, ML, cold pressed and delaminated thin film forms. The harsh conditions needed to etch these MAX phases into MLs, results in their partial oxidation. The hydroxide used to delaminate the MLs results in further oxidation and a reduction in the F-content. In all cases, etching resulted in a decrease in the Ti to Mo ratio implying that the former atoms are selectively etched. In all but the ML Mo2TiC2Tz case, the Mo to C ratio was also reduced. It follows that the loss of Ti also results in the loss of C atoms. Again with the exception of the ML Mo2Ti2C3Tz case, the number of termination moles per formula unit, z, was amp;gt; 2, which is energetically unfavorable and thus unlikely. However, if one assumes that not all of the O signal is coming from terminations but rather from O atoms that replace C atoms in the MX blocks, then z similar to 2. This work is an important step in quantifying and understanding the effects of etching on terminations and structure in these Mo and Ti-based MXenes.
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| 45. |
- Halvorsen, Peter, et al.
(författare)
-
Health-related quality of life after surviving intensive care for COVID-19 : a prospective multicenter cohort study
- 2023
-
Ingår i: Scientific Reports. - : Springer Nature. - 2045-2322. ; 13:1
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Tidskriftsartikel (refereegranskat)abstract
- In survivors of severe coronavirus disease 2019 (COVID-19) incomplete mental and physical recovery may considerably impact daily activities and health-related quality of life (HRQoL). HRQoL can be evaluated with the RAND-36 questionnaire, a multidimensional instrument that assesses physical and mental aspects of health in eight dimensions. The objective was to investigate HRQoL in intensive care patients previously treated for COVID-19 at three Nordic university hospitals, in a prospective multi-center cohort study. HRQoL was measured using RAND-36, 3-9 months after discharge from intensive care units (ICU). One hospital performed a second follow-up 12 months after discharge. A score under the lower limit of the 95% confidence interval in the reference cohorts was considered as significantly reduced HRQoL. We screened 542 and included 252 patients. There was more than twice as many male (174) as female (78) patients and the median age was 61 (interquartile range, IQR 52-69) years. Hypertension was the most common comorbidity observed in 132 (52%) patients and 121 (48%) patients were mechanically ventilated for a median of 8 (IQR 4-14) days. In RAND-36 physical functioning, physical role functioning, general health (p < 0.001 for all) and social functioning (p < 0.05) were below reference, whereas bodily pain, emotional role functioning and mental health were not. In a time-to-event analysis female sex was associated with a decreased chance of reaching the reference HRQoL in the physical function, bodily pain and mental health dimensions. Higher body mass index was found in the physical functioning dimension and hypertension in the physical functioning, vitality and social functioning dimensions. Similar results were seen for diabetes mellitus in general health, vitality and mental health dimensions, as well as pulmonary illness in the physical role functioning dimension and psychiatric diagnosis in the social functioning dimension. Mechanical ventilation was associated with a decreased likelihood of achieving reference HRQoL in the bodily pain and physical functioning dimensions. Patients treated in an ICU because of COVID-19 had lower HRQoL 3-9 months after ICU discharge than 95% of the general population. Physical dimensions were more severely affected than mental dimensions. Female sex and several comorbidities were associated with a slower rate of recovery.
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| 46. |
- Hanif, Imran, et al.
(författare)
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High-temperature corrosion of weld overlay coating/bulk FeCrAl exposed in O2 + H2O + KCl(s) at 600 °C – A microstructural investigation
- 2023
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Ingår i: Journal of Materials Research and Technology. - : Elsevier Editora Ltda. - 2238-7854. ; 25, s. 7008-7023
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Tidskriftsartikel (refereegranskat)abstract
- This work investigates the impact of high-temperature corrosion behavior of the newly developed FeCrAl alloy Kanthal® EF101 bulk material and weld overlay coating in the presence of KCl(g)/KCl(s) at 600 °C. The oxide scale formed within the secondary corrosion regime after exposure and the impact of alloy microstructure on corrosion behavior was investigated using scanning transmission electron microscopy. The findings indicated the key microstructural differences is the alloy grain size which influences the formation of a protective scale. In addition, It is indicated that coating exhibited inferior performance than the bulk material, primarily attributed to the microstructural differences. © 2023 The Author(s)
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| 47. |
- Holm, Johanna, et al.
(författare)
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Associations of breast cancer risk prediction tools with tumor characteristics and metastasis
- 2016
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Ingår i: Journal of Clinical Oncology. - Stockholm : Karolinska Institutet, Dept of Medical Epidemiology and Biostatistics. - 0732-183X. ; 34:3, s. 251-U109
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: The association between established risk factors for breast cancer and subtypes or prognosis of the disease is not well known. We analyzed whether the Tyrer-Cuzick–predicted 10-year breast cancer risk score (TCRS), mammographic density (MD), and a 77-single nucleotide polymorphism polygenic risk score (PRS) were associated with breast cancer tumor prognosticators and risk of distant metastasis. Patients and Methods: We used a case-only design in a population-based cohort of 5,500 Swedish patients with breast cancer. Logistic and multinomial logistic regression of outcomes, estrogen receptor (ER) status, lymph node involvement, tumor size, and grade was performed with TCRS, PRS, and percent MD as exposures. Cox proportional hazard models were used to estimate hazard ratios (HRs) of distant metastasis. Results: Women at high risk for breast cancer based on PRS and/or TCRS were significantly more likely to be diagnosed with favorable prognosticators, such as ER-positive and low-grade tumors. In contrast, PRS weighted on ER-negative disease was associated with ER-negative tumors. When stratifying by age, the associations of TCRS with favorable prognosticators were restricted to women younger than age 50. Women scoring high in both TCRS and PRS had a lower risk of distant metastasis (HR, 0.69; 95% CI, 0.49 to 0.98). MD was not associated with any of the examined prognosticators. Conclusion: Women at high risk for breast cancer based on genetic and lifestyle factors were significantly more likely to be diagnosed with breast cancers with a favorable prognosis. Better knowledge of subtype- specific risk factors could be vital for the success of prevention programs aimed at lowering mortality.
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| 48. |
- Hu, C., et al.
(författare)
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Mo2Ga2C: a new ternary nanolaminated carbide
- 2015
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Ingår i: Chemical Communications. - : Royal Society of Chemistry. - 1359-7345 .- 1364-548X. ; 51:30, s. 6560-6563
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Tidskriftsartikel (refereegranskat)abstract
- We report the discovery of a new hexagonal Mo2Ga2C phase, wherein two Ga layers - instead of one - are stacked in a simple hexagonal arrangement in between Mo2C layers. It is reasonable to assume this compound is the first of a larger family.
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| 49. |
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| 50. |
- Idh, Jonna, et al.
(författare)
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Reduced susceptibility of clinical strains of Mycobacterium tuberculosis to reactive nitrogen species promotes survival in activated macrophages
- 2017
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Ingår i: PLOS ONE. - : PLOS. - 1932-6203. ; 12:7
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Tidskriftsartikel (refereegranskat)abstract
- Background Drugs such as isoniazid (INH) and pretomanid (PRT), used against Mycobacterium tuberculosis are active partly through generation of reactive nitrogen species (RNS). The aim of this study was to explore variability in intracellular susceptibility to nitric oxide (NO) in clinical strains of M. tuberculosis. Method Luciferase-expressing clinical M. tuberculosis strains with or without INH resistance were exposed to RNS donors (DETA/NO and SIN-1) in broth cultures and bacterial survival was analysed by luminometry. NO-dependent intracellular killing in a selection of strains was assessed in interferon gamma/lipopolysaccharide-activated murine macrophages using the NO inhibitor L-NMMA. Results When M. tuberculosis H37Rv was compared to six clinical isolates and CDC1551, three isolates with inhA mediated INH resistance showed significantly reduced NO-susceptibility in broth culture. All strains showed a variable but dose-dependent susceptibility to RNS donors. Two clinical isolates with increased susceptibility to NO exposure in broth compared to H37Rv were significantly inhibited by activated macrophages whereas there was no effect on growth inhibition when activated macrophages were infected by clinical strains with higher survival to NO exposure in broth. Furthermore, the most NO-tolerant clinical isolate showed increased resistance to PRT both in broth culture and the macrophage model compared to H37Rv in the absence of mutational resistance in genes associated to reduced susceptibility against PRT or NO. Conclusion In a limited number of clinical M. tuberculosis isolates we found a significant difference in susceptibility to NO between clinical isolates, both in broth cultures and in macrophages. Our results indicate that mycobacterial susceptibility to cellular host defence mechanisms such as NO need to be taken into consideration when designing new therapeutic strategies.
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