| 11. |
- Dick Thelander, Kimberly, et al.
(författare)
-
Parameter space mapping of InAs nanowire crystal structure
- 2011
-
Ingår i: Journal of Vacuum Science and Technology B. - : American Vacuum Society. - 1520-8567. ; 29:4
-
Tidskriftsartikel (refereegranskat)abstract
- Crystal structure and defects have been shown to have a strong impact on III-V nanowire properties. Recently, it was demonstrated that the issue of random stacking and polytypism in semiconductor nanowires can often be controlled using accessible growth parameters (such as temperature, diameter, and V/III ratio). In addition, it has been shown that crystal phase can be tuned selectively between cubic zinc blende and hexagonal wurtzite within individual nanowires of III-V materials such as InAs. In order for such results to be generally applied to different growth setups, it is necessary to fully explore and understand the trends governing crystal phase dependencies on all accessible growth parameters, including how they relate to each other. In this study, the authors have systematically investigated the influence of temperature, diameter, V/III ratio, and total mass flow on the crystal structure of InAs nanowires grown by metal-organic vapor phase epitaxy over a broad parameter range. The authors observed that each of these accessible parameters can affect the resulting crystal structure, and that the trends for each parameter are affected by the magnitude of the others. The authors also noted that most of the parameter dependencies are nonlinear and, in fact, exhibit threshold values at which structure changes discontinuously. By optimizing each of the growth parameters, it is shown that pure ZB or pure WZ phase can be achieved for several different sets of growth conditions. The roles of nucleation kinetics, thermodynamics, and precursor chemistry are also discussed to compare the results to current nanowire growth models. The results in this work should facilitate comparison of data and transfer of knowledge between different growth systems and techniques, which, in turn, should lead to greater understanding of polytypism in nanowires and greater control and freedom in nanowire crystal phase engineering. (C) 2011 American Vacuum Society. [DOI: 10.1116/1.3593457]
|
|
| 12. |
- Eriksson, Henrik, et al.
(författare)
-
His helping hands-adult daughter's perceptions' of fathers with caregiving responsibility
- 2013
-
Ingår i: European Journal of Social Work. - : Informa UK Limited. - 1369-1457 .- 1468-2664. ; 16:2, s. 235-248
-
Tidskriftsartikel (refereegranskat)abstract
- Women's position as informal carers has been taken for granted in social policy and social professions, while relatively few discussions have elaborated on caring as a later life activity for men and the impact on family care. This study explores the processes connected to informal caregiving in later life through the position of adult daughters of older fathers engaged with long-term caregiving responsibilities for a partner. A sample of eight daughters, with fathers having primary caregiving responsibility for their ill partners was recruited and in-depth interviews were carried out and analysed according to qualitative procedures. The daughters' descriptions of their relationships with their fathers show that being an older man who engages in caring can have a positive outcome on relations. Even if some of the daughters have doubts about their fathers “masculine authenticity”, all of them appear to cherish “his helping hands” as a carer and closer more intimate relationships with their fathers. Caring for an old and frail spouse may potentially present alternative ways of being a man beyond traditional ‘male activities’ and that caring might also sometimes involve a re-construction of gender identities. It is suggested that social work professionals may use a gendered understanding to assess and work strategically with daughters and other family members who support caring fathers.
|
|
| 13. |
- Fuks, Jonas M, et al.
(författare)
-
GABAergic Signaling Is Linked to a Hypermigratory Phenotype in Dendritic Cells Infected by Toxoplasma gondii
- 2012
-
Ingår i: PLoS pathogens. - : Public Library of Science (PLoS). - 1553-7374. ; 8:12, s. e1003051-
-
Tidskriftsartikel (refereegranskat)abstract
- During acute infection in human and animal hosts, the obligate intracellular protozoan Toxoplasma gondii infects a variety of cell types, including leukocytes. Poised to respond to invading pathogens, dendritic cells (DC) may also be exploited by T. gondii for spread in the infected host. Here, we report that human and mouse myeloid DC possess functional γ-aminobutyric acid (GABA) receptors and the machinery for GABA biosynthesis and secretion. Shortly after T. gondii infection (genotypes I, II and III), DC responded with enhanced GABA secretion in vitro. We demonstrate that GABA activates GABA(A) receptor-mediated currents in T. gondii-infected DC, which exhibit a hypermigratory phenotype. Inhibition of GABA synthesis, transportation or GABA(A) receptor blockade in T. gondii-infected DC resulted in impaired transmigration capacity, motility and chemotactic response to CCL19 in vitro. Moreover, exogenous GABA or supernatant from infected DC restored the migration of infected DC in vitro. In a mouse model of toxoplasmosis, adoptive transfer of infected DC pre-treated with GABAergic inhibitors reduced parasite dissemination and parasite loads in target organs, e.g. the central nervous system. Altogether, we provide evidence that GABAergic signaling modulates the migratory properties of DC and that T. gondii likely makes use of this pathway for dissemination. The findings unveil that GABA, the principal inhibitory neurotransmitter in the brain, has activation functions in the immune system that may be hijacked by intracellular pathogens.
|
|
| 14. |
|
|
| 15. |
- Gilbert, Jonas, 1968, et al.
(författare)
-
To Follow-Up Open Access Policies. What to Measure, How to Do It and Who to Tell
- 2011
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The implementation of open access has gained momentum in Sweden with policiesbeing adopted by universities and funding bodies. Representing two organizationswith policy decisions from 2010, we now face the question how we should evaluatethe impact of the policies. It is clearly important for us to be able to measure and toevaluate the progress at the early stages in this process. We also believe that differentstakeholders – university management, research group leaders and the individualresearchers – will benefit from different kinds of feedback and that we should beable to provide adjusted indicators for these groups.
|
|
| 16. |
- Gustafsson, Magnus, 1965, et al.
(författare)
-
The challenges and benefits of criterion-based assessment: combining feedback channels and exploring criterion-based supervision
- 2014
-
Ingår i: The challenges and benefits of criterion-based assessment: combining feedback channels and exploring criterion-based supervision.
-
Konferensbidrag (refereegranskat)abstract
- This presentation combines the findings from two studies. One study compares students’ experiences criteria-based assessment via in-text commentary and rubric-articulated feedback in an assessment design combining the two feedback channels. We use students’ responses to inform possible ways of optimizing feedback strategies for formative assessment. Categories of student responses from three sources are discussed: reflective texts, a questionnaire, and interviews. Results indicate that students attributed different functions to the two feedback channels: in-text commentary to later-order concerns related to language proficiency, and rubric-articulated feedback to higher-order concerns related to an overview of writing achievement. The second study investigates adapting supervision for greater impact of university-wide guidelines and criteria for MSc and Bachelor of Engineering theses. The study involves a faculty-training group at MSc and BEng levels and an analysis of the work supervisors and students have been doing to interpret criteria and thus contextualize them for their projects. Findings indicate that isolated supervisors have little sense of the potential of the criteria and that a collegial discussion is crucial to generate understanding and supporting activities.Both studies exemplify how internalization of a discipline’s standard is often insufficient and how a revised supervision process promotes student ownership and their informed engagement in thesis/assignment quality. So, while presenting the findings in terms of the initial interpretation of criteria among students and faculty is important, the presentation also needs to address the learning oriented interventions of revised supervision practices. The presentation, therefore, ends on some ‘lessons learned’ and synergy effects of a combination of reading seminars, in-text commentary, and rubric-articulated feedback for formative purposes. We also discuss current assessment designs and potential improvement to these towards. We hope this discussion is relevant to WRAB colleagues.
|
|
| 17. |
- Johansson, Jonas, et al.
(författare)
-
Combinatorial Approaches to Understanding Polytypism in III-V Nanowires.
- 2012
-
Ingår i: ACS Nano. - : American Chemical Society (ACS). - 1936-086X .- 1936-0851. ; 6:7, s. 6142-6149
-
Tidskriftsartikel (refereegranskat)abstract
- Polytypism in III-V semiconductor nanowires is a topic that has received considerable attention in recent years. Achieving a pure nanowire crystal phase requires well-controlled and advanced parameter tuning for most III-V materials. Additionally, the new and unusual phases sometimes observed may present unique material properties if they can be controllably fabricated. With the prospect of using nanowires in applications within several different fields (including electronics, photonics, and life science), theoretical models are necessary to explain experimental trends and to attain a high level of crystal phase control. At present, there is no theoretical model (or combination of models) that fully explains how and why nanowire crystal structures commonly include several different polytypes. Here we use combinatorics and interlayer interactions to include higher order polytypes (4H and 6H) with the aim to explain nanowire crystal structure beyond the well-investigated zinc blende-wurtzite polytypism. Predictions from our theoretical models compare well with experimental results.
|
|
| 18. |
|
|
| 19. |
- Johansson, Jonas, et al.
(författare)
-
Diameter Dependence of the Wurtzite-Zinc Blende Transition in InAs Nanowires
- 2010
-
Ingår i: Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 114:9, s. 3837-3842
-
Tidskriftsartikel (refereegranskat)abstract
- We demonstrate that the crystal structure of InAs nanowires call be controlled with nanowire diameter and growth temperature. At small diameters, the nanowires exhibit a wurtzite Structure. As the diameter is increased, there is a crossover to the zinc blende structure. The crossover is less sharp at lower growth temperature and L, the crossover diameter decreases as the growth temperature is increased. We explain these results with classical nucleation theory. The strong diameter dependence is accounted for by including the Gibbs-Thomson effect in the chemical potential.
|
|
| 20. |
|
|
