| 1. |
- Bohlin, Gustav, 1981-, et al.
(författare)
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A conceptual characterization of online videos explaining natural selection
- 2017
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Ingår i: Science & Education. - : Springer Netherlands. - 0926-7220 .- 1573-1901. ; 26:7-9, s. 975-999
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Tidskriftsartikel (refereegranskat)abstract
- Educational videos on the Internet comprise a vast and highly diverse source of information. Online search engines facilitate access to numerous videos claiming to explain natural selection, but little is known about the degree to which the video content match key evolutionary content identified as important in evolution education research. In this study, we therefore analyzed the content of 60 videos accessed through the Internet, using a criteria catalog with 38 operationalized variables derived from research literature. The variables were sorted into four categories: (a) key concepts (e.g. limited resources and inherited variation), (b) threshold concepts (abstract concepts with a transforming and integrative function), (c) misconceptions (e.g. that evolution is driven by need), and (d) organismal context (e.g. animal or plant). The results indicate that some concepts are frequently communicated, and certain taxa are commonly used to illustrate concepts, while others are seldom included. In addition, evolutionary phenomena at small temporal and spatial scales, such as subcellular processes, are rarely covered. Rather, the focus is on population-level events over time scales spanning years or longer. This is consistent with an observed lack of explanations regarding how randomly occurring mutations provide the basis for variation (and thus natural selection). The findings imply, among other things, that some components of natural selection warrant far more attention in biology teaching and science education research.
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| 2. |
- Bohlin, Gustav, 1981-
(författare)
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Evolving germs – Antibiotic resistance and natural selection in education and public communication
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Bacterial resistance to antibiotics threatens modern healthcare on a global scale. Several actors in society, including the general public, must become more involved if this development is to be countered. The conveyance of relevant information provided through education and media reports is therefore of high concern. Antibiotic resistance evolves through the mechanisms of natural selection; in this way, a sound understanding of these mechanisms underlies explanations of causes and the development of effective risk-reduction measures. In addition to natural selection functioning as an explanatory framework to antibiotic resistance, bacterial resistance as a context seems to possess a number of qualities that make it suitable for teaching natural selection – a subject that has been proven notoriously hard to teach and learn. A recently suggested approach for learning natural selection involves so-called threshold concepts, which encompass abstract and integrative ideas. The threshold concepts associated with natural selection include, among others, the notions of randomness as well as vast spatial and temporal scales. Illustrating complex relationships between concepts on different levels of organization is one, of several, areas where visualizations are efficient. Given the often-imperceptible nature of threshold concepts as well as the fact that natural selection processes occur on different organizational levels, visual accounts of natural selection have many potential benefits for learning.Against this background, the present dissertation explores information conveyed to the public regarding antibiotic resistance and natural selection, as well as investigates how these topics are presented together, by scrutinizing media including news reports, websites, educational textbooks and online videos. The principal method employed in the media studies was content analysis, which was complemented with various other analytical procedures. Moreover, a classroom study was performed, in which novice pupils worked with a series of animations explaining the evolution of antibiotic resistance. Data from individual written assignments, group questions and video-recorded discussions were collected and analyzed to empirically explore the potential of antibiotic resistance as a context for learning about evolution through natural selection.Among the findings are that certain information, that is crucial for the public to know, about antibiotic resistance was conveyed to a low extent through wide-reaching news reporting. Moreover, explanations based on natural selection were rarely included in accounts of antibiotic resistance in any of the examined media. Thus, it is highly likely that a large proportion of the population is never exposed to explanations for resistance development during education or through newspapers. Furthermore, the few examples that were encountered in newspapers or textbooks were hardly ever visualized, but presented only in textual form. With regard to videos purporting to explain natural selection, it was found that a majority lacked accounts of central key concepts. Additionally, explanations of how variation originates on the DNA-level were especially scarce. These and other findings coming from the content analyses are discussed through the lens of scientific literacy and could be used to inform and strengthen teaching and scientific curricula with regards to both antibiotic resistance and evolution. Furthermore, several factors of interest for using antibiotic resistance in the teaching of evolution were identified from the classroom study. These involve, among others, how learners’ perception of threshold concepts such as randomness and levels of organization in space and time are affected by the bacterial context
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| 3. |
- Bohlin, Gustav, 1981-, et al.
(författare)
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Evolving germs – Introducing novice pupils to the evolution of bacterial resistance to antibiotics
- 2017
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- There is a dual relationship between antibiotic resistance and biological evolution. Antibiotic resistance is typically used as a motivation for why we need an efficient evolution education given that evolutionary reasoning improves our understanding of causes and suggested countermeasures. On the other hand, antibiotic resistance has also been suggested as a useful context in which evolution can be taught, based primarily but not solely on the quick generation times of bacteria. In the present study, we explore the potential benefits with using antibiotic resistance as an example when introducing evolution to novice pupils (aged 13-14). We created a series of animations that pupils interacted with in groups of 3-5 (total n=32). Data was collected on both individual (pre-posttest) and group (collaborative group questions) level. In addition, the exercise was video-taped and the full transcripts were analyzed inductively. The results show that a majority of the pupils succeeded in applying basic evolutionary reasoning to make predictions on antibiotic resistance during and after the exercise, suggesting that this may be a successful approach. Cautions to be aware of include pupils’ use of teleological and antropomorphic reasoning, especially in discussions on submicroscopical phenomena such as genetic processes. Implications for teaching include both lessons from the design of animations as well as the identification of common misunderstandings. The analysis also identifies and points toward several possible future research endeavours.
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| 4. |
- Bohlin, Gustav, 1981-, et al.
(författare)
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Insights from introducing natural selection to novices using animations of antibiotic resistance
- 2018
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Ingår i: Journal of Biological Education. - : Taylor & Francis. - 0021-9266 .- 2157-6009. ; 52:3, s. 314-330
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Tidskriftsartikel (refereegranskat)abstract
- Antibiotic resistance is typically used to justify education about evolution, as evolutionary reasoning improves our understanding of causes of resistance and possible countermeasures. It has also been promoted as a useful context for teaching natural selection, because its potency as a selection factor, in combination with the very short generation times of bacteria, allows observation of rapid selection. It is also amenable to animations, which have potential for promoting conceptual inferences. Thus, we have explored the potential benefits of introducing antibiotic resistance as a first example of natural selection, in animations, to novice pupils (aged 13–14 years). We created a series of animations that pupils interacted with in groups of 3–5 (total n = 32). Data were collected at individual (pre-/post- test) and group (collaborative group questions) levels. In addition, the exercise was video-recorded and the full transcripts were analysed inductively. The results show that most of the pupils successfully applied basic evolutionary reasoning to predict antibiotic resistance development in tasks during and after the exercise, suggesting that this may be an effective approach. Pedagogical contributions include the identification of certain characteristics of the bacterial context for evolution teaching, including common misunderstandings, and factors to consider when designing animations.
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| 5. |
- Brandhorst, Heide, 1962-, et al.
(författare)
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A new oxygen carrier for improved long-term storage of human pancreata before islet isolation
- 2010
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Ingår i: Transplantation. - 0041-1337 .- 1534-6080. ; 89:2, s. 155-60
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Pancreas oxygenation during cold storage has been established in islet isolation and transplantation to prevent ischemic tissue damage using perfluorodecalin (PFD) as hyperoxygen carrier. However, studies in humans and pigs provided conflicting results about the efficiency of PFD for pancreas oxygenation. The aim of this study was to compare PFD with a newly developed oxygen carrier composed of perfluorohexyloctane and polydimethylsiloxane 5 (F6H8S5) for long-term storage of human pancreata.METHODS: After 24-hr storage in preoxygenated PFD or F6H8S5, pancreata were processed using Liberase HI for pancreas dissociation and a Ficoll gradient for islet purification. Islet quality assessment was performed measuring glucose-stimulated insulin release, viability, islet ATP content, and posttransplant function in diabetic nude mice.RESULTS: Compared with PFD, F6H8S5 significantly increased the intrapancreatic partial oxygen pressure and islet ATP content. This corresponded to an increase of islet yield, recovery after culture, glucose stimulation index, viability, and improved graft function in diabetic nude mice.CONCLUSIONS: The present findings indicate clearly that F6H8S5 improves isolation outcome after prolonged ischemia compared with PFD. This observation seems to be related to the significant lipophilicity and almost pancreas-specific density of F6H8S5. Moreover, these characteristics facilitate pancreas shipment without using custom-made transport vessels as required for PFD.
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| 6. |
- Brandhorst, Heide, et al.
(författare)
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Large-Scale Comparison of Liberase HI and Collagenase NB1 Utilized for Human Islet Isolation
- 2010
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Ingår i: Cell Transplantation. - 0963-6897 .- 1555-3892. ; 19:1, s. 3-8
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Tidskriftsartikel (refereegranskat)abstract
- For more than a decade Liberase HI was commonly used as the standard enzyme blend for clinical human islet isolation until enforced replacement by collagenase NB1 (NB1). This change resulted initially in a reduction in islet isolation outcome and transplant activities worldwide. This retrospective study was initiated to compare the efficiency of NB1 premium grade with Liberase in 197 human islet isolations. All pancreata were processed between January 2006 and June 2008 utilizing the same procedures for isolation and quality assessment except the administration of preselected lots of either Liberase (n = 101) or NB1 (n = 96). Utilizing Liberase significantly more digested tissue and purified islet yield was produced compared to NB1. In contrast, the use of NB1 was associated with significantly higher purity and glucose stimulation index during dynamic perifusion. The expression of proinflammatory markers was almost identical except tissue factor expression that was higher after utilization of Liberase. No difference was found in the percentage of pancreata fulfilling the criteria for clinical islet transplantation. The results suggest that Liberase is more efficient for pancreas dissociation than collagenase NB1 but seems to be more harmful to exocrine cells and islet tissue.
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| 7. |
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| 8. |
- Caballero-Corbalán, José, et al.
(författare)
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Using HTK for Prolonged Pancreas Preservation Prior to Human Islet Isolation
- 2012
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Ingår i: Journal of Surgical Research. - : Elsevier BV. - 1095-8673 .- 0022-4804. ; 175:1, s. 163-168
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Tidskriftsartikel (refereegranskat)abstract
- Background. Histidine-tryptophan-ketoglutarate (HTK) has been established as an alternative to University-of-Wisconsin solution (UWS) for abdominal organ preservation, but data about HTK efficiency to preserve pancreata during prolonged cold ischemia time (CIT) are conflicting. In human islet transplantation, HTK provided similar isolation outcomes after short CIT. The present study aimed to investigate whether islets can be successfully isolated from HTK-preserved pancreata after prolonged CIT compared with UWS. Materials and Methods. Sixty-four human pancreata retrieved from donors meeting criteria for kidney donation were perfused utilizing either HTK or UWS and preserved for more or less than 10 h prior to islet isolation. Along with parameters related to isolation and islet quality assessment, the dry-to-wet weight ratio was evaluated. Results. Donor-and procurement-related factors did not vary between HTK- and UWS-perfused pancreata. The dry-to-wet weight ratio was lower in HTK-preserved pancreata indicated tissue edema (21.0% +/- 3.5% versus 24.8% +/- 2.0%, P = 0.007). Isolation-related variables differed between experimental groups after prolonged CIT with respect to purified packed tissue volume (9.1 +/- 5.0 versus 17.2 +/- 8.1 mu L/g, P = 0.004) and islet yield (1910 +/- 980 versus 3150 +/- 1420 IE/g, P = 0.012). Islet purity and survival after culture were similar after HTK or UWS perfusion. The preservation solution did not affect in vitro function and transplantability of isolated islets. Conclusions. Compared with UWS, HTK has similar efficiency to preserve human pancreata for subsequent islet isolation during <10 h CIT but seems to be limited for prolonged cold storage. (C) 2012 Elsevier Inc. All rights reserved.
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| 9. |
- Friberg, Andrew S., et al.
(författare)
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Transplanted functional islet mass : donor islet preparation, and recipitent factors influence early graft function in islet-after-kidney patients
- 2012
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Ingår i: Transplantation. - 0041-1337 .- 1534-6080. ; 93:6, s. 632-638
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Tidskriftsartikel (refereegranskat)abstract
- Background.The ability to predict clinical function of a specific islet batch released for clinical transplantation using standardized variables remains an elusive goal.Methods. Analysis of 10 donor, 7 islet isolation, 3 quality control, and 6 recipient variables was undertaken in 110 islet-after-kidney transplants and correlated to the pre- to 28-day posttransplant change in C-peptide to glucose and creatinine ratio ([DELTA]CP/GCr).Results.Univariate analysis yielded islet volume transplanted (Spearman r=0.360, P<0.001) and increment of insulin secretion (r=0.377, P<0.001) as variables positively associated to [DELTA]CP/GCr. A negative association to [DELTA]CP/GCr was cold ischemia time (r=-0.330, P<0.001). A linear, backward-selection multiple regression was used to obtain a model for the transplanted functional islet mass (TFIM). The TFIM model, composed of islet volume transplanted, increment of insulin secretion, cold ischemia time, and exocrine tissue volume transplanted, accounted for 43% of the variance of the clinical outcome in the islet-after-kidney data set.Conclusion.The TFIM provides a straightforward and potent tool to guide the decision to use a specific islet preparation for clinical transplantation.
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| 10. |
- Höst, Gunnar E., 1976-, et al.
(författare)
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Methods for investigating students’ learning and interaction with a haptic virtual biomolecular model
- 2010
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Ingår i: Contemporary Science Education Research: International Perspectives. - Ankara : Pegem Akademi. - 9786053640318 ; , s. 115-121
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Konferensbidrag (refereegranskat)abstract
- Although immersive haptic virtual technologies are emerging rapidly in modern education, few methods exist for delivering data on the pedagogical merits of such models in the molecular life sciences. This paper reports on a selection of methods that we have used to obtain and analyse data on students’ learning and interaction with a haptic virtual model of protein-ligand docking, previously designed by author PBP. The methods have been developed and employed during four consecutive years in which the model has been part of an advanced biomolecular interactions course. In this regard, we present data-collection methods that include written items, interviews, think-aloud tasks and automated time-stamped logs and, corresponding quantitative and qualitative analytical procedures such as pre/posttest statistical comparisons, word usage analysis and, visualised profiling of students’ interaction with the model. Our results suggest that these methods are useful for generating valuable information on students’ learning gain, changes in conceptual understanding, reasoning processes and patterns of interactivity with the model. Dissemination of such methods could provide an empirical contribution to the dearth of research instruments in this domain. Future research will develop these methodologies to explore the relationship between using the model and students’ conceptual and embodied learning.
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