| 149281. |
- Linder, Arne, et al.
(författare)
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Using the carbon dioxide laser for tonsillotomy in children
- 1999
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Ingår i: International Journal of Pediatric Otorhinolaryngology. - 0165-5876 .- 1872-8464. ; 50:1, s. 31-6
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Tidskriftsartikel (refereegranskat)abstract
- Carbon dioxide laser tonsillotomies were performed on 33 children aged 1-12 years for the relief of obstructive symptoms due to tonsillar hyperplasia. As opposed to conventional tonsillectomy, only the protruding part of each tonsil was removed. A carbon dioxide laser delivering 20 W was used for the excision. Twenty-one children were seen in active short-term follow-up and the records of all the children were checked for possible surgery related events up to 20-33 months after surgery. Laser tonsillotomy was uniformly effective in relieving the obstruction, with good hemostasis. The tonsillar remnants healed completely within 2 weeks. No major adverse events occurred. Post-operative pain appeared slight and easily controlled. There was no gain in operating time compared with conventional tonsillectomy. The laser tonsillotomies were in most cases done in day surgery. No recurrence of obstructive problems was reported up to 20-33 months after surgery. It was concluded that tonsillotomy, using a carbon dixoide laser, is a valid treatment for obstructive symptoms caused by enlarged tonsils, which can be performed with little bleeding and post-operative pain. The improved hemostasis may enable a shift from in-patient to day surgery.
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| 149282. |
- Linder, Birgitta, et al.
(författare)
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In vitro growth of human endolymphatic sac cells : a transmission electron microscopic and immunohistochemical study in patients with vestibular schwannoma and Ménière's Disease
- 2001
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Ingår i: Otology and Neurotology. - 1531-7129 .- 1537-4505. ; 22:6, s. 938-943
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Tidskriftsartikel (refereegranskat)abstract
- HYPOTHESIS:Human endolymphatic sac cells have been notoriously difficult to maintain in culture. It was hypothesized that an in vitro environment intended for growth of keratinocytes would also be suitable for human endolymph sac cells.BACKGROUND:Studies on cell physiology of human endolymphatic sac cells have been hampered by difficulties in maintaining them in culture.METHODS:Human endolymphatic sac cells were taken from 10 patients during translabyrinthine skull base surgery for vestibular schwannoma, one of whom also had Ménière's disease. Cell lines of proliferating epithelial cells were obtained after trypsinization and growth in a 3:1 mixture of Dulbecco's modified Eagle medium and Ham's F12 medium supplemented with 10% fetal calf serum. Fibroblast overgrowth was counteracted by the use of so-called cloning rings. During various stages, cells were investigated with transmission electron microscopy and/or immunohistochemistry.RESULTS:Proliferation took place after 2 to 3 days of primary cell culture. The cells were cytokeratin-positive and pleomorphic, and they had abundant polarized microvillus-like projections, numerous coated cytoplasmic pits and vesicles, and a well-developed rough endoplasmic reticulum.CONCLUSION:Cell lines of proliferating human endolymphatic sac cells can be produced with the technique described here and may be a valid tool in studies of human endolymph sac physiology.
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| 149283. |
- Linder, Cedric
(författare)
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A challenge to conceptual change
- 1993
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Ingår i: Science Education. - 0036-8326 .- 1098-237X. ; 77:3, s. 293-300
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Tidskriftsartikel (refereegranskat)
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| 149284. |
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| 149285. |
- Linder, Cedric, et al.
(författare)
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An exploratory study into the complexity of relations between physics lecturers' crafting of practice and students' expectations of quality teaching
- 2011
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Ingår i: Instructional science. - : Springer Science and Business Media LLC. - 0020-4277 .- 1573-1952. ; 39:4, s. 513-526
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Tidskriftsartikel (refereegranskat)abstract
- This study contributes to research that characterises the affective learning thatis evoked and taken on by students in response to their perceptions of their contextuallearning environments. Interview-discussions were held with lecturers of both introductoryand higher-level physics courses (n = 3) concerning how they formulated their patterns ofteaching in terms of a particular conceptual framing that they considered to best optimizemaking learning possible. Subsequently their students (n = 212) were asked with writtenquestions, and some select follow-up interview-discussions, to describe what they expectedfrom ‘a good physics lecturer’. The relationships between these two things—the lecturer’scrafting of practice and the students’ expectations of quality teaching—were investigated.Results show that students’ expectations tend to match their lecturers’ practice, indicatingthat students are strongly influenced by a contextually based appreciation of ‘good’teaching.
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| 149286. |
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| 149287. |
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| 149288. |
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| 149289. |
- Linder, Cedric, et al.
(författare)
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Categories of influence: the case of light and sound in physics
- 2015
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Ingår i: Part of an invited seminar on: Content-focused research on student and teacher learning in the field of optics.
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Konferensbidrag (refereegranskat)abstract
- In any given physics education situation students will spontaneously respond as a function of the features of the situation that they feel are relevant; what the situation is seen to call for. In phenomenography, a research approach that aims to capture variation in terms of qualitative differences in educational experience, this is referred to as the “relevance structure”. This construct is virtually unknown in physics education circles, yet it opens a realm of possible educational interventions that could dramatically alter physics students’ learning experiences. This is because it shifts the learning experience focus on to facilitating the noticing of critical parts by design in ways that have been shown to distinctly enhance the possibility of learning. We propose that relevance structure is made up of categories of influence that play an important role in mediating and influencing both new learning and applications of what has already been learned. To support our proposal, while exemplifying relevance structure in a physics education context, 18 graduate physics students were asked to compare and contrast the physics concepts of light and sound. The data was collected using semi-structured interviews that had as their starting point a textbook-given generalized wave equation for a wave ψ (x, t) traveling in the x direction with speed v. All discussion was audio recorded. For the analysis, all of the interview discussion was transcribed verbatim and the methodology followed the phenomenographic form of the iterative constant comparative approach, which is at the collective rather than individual level. Three categories of influence were found. These are discussed in terms of educational insight into differences that are seen to be critical. The implication that physics teachers need to actively help students develop more coherent and connected relevance structure for given educational tasks is discussed and exemplified.
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| 149290. |
- Linder, Clara, et al.
(författare)
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Cobalt thin films as water-recombination electrocatalysts
- 2020
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Ingår i: Surface & Coatings Technology. - : Elsevier B.V.. - 0257-8972 .- 1879-3347. ; 404
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Tidskriftsartikel (refereegranskat)abstract
- Catalysts and electrocatalysts are crucial for energy production and storage. To develop cost-efficient systems taking advantage of functionalized surfaces, the catalysts can be synthesized as nanomaterials or thin films. In this work, cobalt thin films were deposited on low-alloyed steel using magnetron sputtering. The films are uniform with a smooth surface and a thickness of ~400 nm. The films were electrochemically oxidized via anodization to a mix of cobalt oxides, one of them being Co3O4, at room temperature in an alkaline solution. The electrocatalytic performances of the anodized films were evaluated in 1 M KOH electrolyte saturated with oxygen. Cathodic currents in −0.5 mA/cm2 range, corresponding to oxygen reduction reaction (ORR) activity, were measured with cyclic voltammetry. The catalytic activity of the films was evaluated as a function of time. The anodized Co coating exhibited three times higher activity than the steel substrate. The kinetics for the ORR were evaluated through Tafel plots and a slope of 226 mV/decade was found. Post-ORR characterization of the films revealed hexagonal plate-like oxide particles on the surface. After 50 cyclic voltammograms, the film was further oxidized, indicating that the ORR activity also affects the overall surface state of the film. This study demonstrates that thin films, after electrochemical modification, can be electrocatalysts for the oxygen reduction reaction and potentially used for applications in energy production and storage. © 2020 The Authors
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