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  • 1. Agdal, Maren Lillehaug
    et al.
    Raadal, Magne
    Öst, Lars-Göran
    Stockholm University, Faculty of Social Sciences, Department of Psychology.
    Skaret, Erik
    Quality-of-life before and after cognitive behavioral therapy (CBT) in patients with intra-oral injection phobia2012In: Acta Odontologica Scandinavica, ISSN 0001-6357, E-ISSN 1502-3850, Vol. 70, no 6, p. 463-470Article in journal (Refereed)
    Abstract [en]

    Objective. To evaluate quality-of-life (QoL), before and after cognitive behavioral therapy (CBT) in patients diagnosed with intra-oral injection phobia according to DSM-IV and to compare with the general population. This study also aimed to evaluate if QoL was associated with self-reported injection anxiety, dental anxiety, time since last dental treatment and oral health. Materials and methods. Subjects were 55 patients (mean age 35.5 +/- 12.2, 78.2% women) who participated in a treatment study in which 89% managed an intra-oral injection at 1 year follow-up. The patients completed a set of questionnaires including Quality of Life Inventory (QOLI), Injection Phobia Scale-Anxiety, Dental Anxiety Scale and a single-item question assessing self-perceived oral health. Objective measures of oral health and treatment needs were based on clinical examination. QOLI-scores from a non-clinical sample were used for comparison. Results. Before treatment the general and health specific QoL were lower among intra-oral injection phobics than in the non-clinical sample. At 1 year follow-up the QoL in general had improved significantly and was similar to that of the non-clinical sample. Poor self-reported oral health and long-term avoidance of dental treatment were associated with lower general and health-specific QoL. Self-reported injection anxiety and dental anxiety were not associated with QoL. Conclusions. Patients with intra-oral injection phobia report lower QoL compared with a general population. Phobia treatment seems to increase QoL to normative levels. Self-perceived poor oral health is associated with reduced QoL in these patients.

  • 2. Bayat, Jari Taghavi
    et al.
    Hallberg, Ulrika
    Lindblad, Frank
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Uppsala University.
    Huggare, Jan
    Mohlin, Bengt
    Daily life impact of malocclusion in Swedish adolescents: A grounded theory study2013In: Acta Odontologica Scandinavica, ISSN 0001-6357, E-ISSN 1502-3850, Vol. 71, no 3-4, p. 792-798Article in journal (Refereed)
    Abstract [en]

    Objective. To explore how malocclusions affect daily life in adolescents and how adolescents cope with malocclusion-related distress. Materials and methods. Twelve strategically selected teenagers, seven girls and five boys aged 13-14 years, participated in this study. Open, tape-recorded in-depth interviews based on Focus Group Discussions (FGD) were performed using a theme guide and analyzed according to the qualitative method of classic grounded theory (GT). Results. A core category was identified and named 'Repeatedly reminded of the malocclusion'. Associated to the core category, five categories were generated and labeled 'Being directed by the media's ideal image', 'Monitoring others' teeth', 'Struggling with low self-esteem', 'Hiding one's teeth' and 'Striving for cure'. Low self-esteem appeared to be frequently reinforced through the concerns for the malocclusion and handled via different coping strategies, such as hiding the teeth and striving to receive orthodontic treatment. Such processes were further enforced through the influence of media. Low self-esteem could be associated to a visible malposition of teeth, according to the informants. Having to wait for orthodontic treatment was frustrating the adolescents. Conclusions. Adolescents with malocclusion are often reminded of their condition, which can lead to avoiding strategies to minimize the negative feelings associated with the teeth and low self-esteem. Clinicians may therefore need to be aware of potential irrational behaviors when interacting with adolescents with malocclusions. The findings also suggest that there might be a discrepancy of attitudes between professionals focusing on oral health aspects of malocclusions and the adolescents focusing on esthetic aspects.

  • 3. Bergdahl, Maud
    et al.
    Bergdahl, Jan
    Nyberg, Lars
    Nilsson, Lars-Göran
    Stockholm University, Faculty of Social Sciences, Department of Psychology.
    Difference in apolipoprotein E type 4 allele (APOE ɛ4) among dentate and edentulous subjects2008In: Gerodontology, ISSN 0734-0664, E-ISSN 1741-2358, Vol. 25, no 3, p. 179-186Article in journal (Refereed)
    Abstract [en]

    Objectives: To evaluate the frequency of apolipoprotein (APOE) alleles and determine whether APOE type 4 allele (ɛ4) was associated with edentulousness even when certain factors were controlled.

    Background: The APOE are important in lipid homeostasis, and APOE ɛ4 has been found in many diseases and to have a negative impact on longevity. Tooth loss is more common in ill aged subjects with low income and education.

    Materials and methods: In a population-based study involving 1860 subjects between 35 and 85 years 1321 dentate (mean age = 54; 54% women, 46% men) and 539 edentulous (mean age = 72; 62% women, 38% men) subjects were studied. Logistic regression was performed with dentate/edentulous as dependent variables and years of education, socio-economic status, social network, stress level, handicap from birth, 23 various diseases and APOE ɛ4 as covariates. Thereafter, APOE ɛ4 frequencies were studied in 342 dentate and 336 edentulous subjects 50–85 years of age. The subjects were matched with regard to age, gender, years of education, living condition, stress level, handicap from birth and 23 various diseases.

    Results: APOE allele frequency in the total group was ɛ2 = 7.8%, ɛ3 = 76.4% and ɛ4 = 15.8%. Age, living condition, years of education and APOE ɛ4 were significant covariates in edentulous subjects (p ≤ 0.001). APOE ɛ4 in the matched groups revealed significant differences between the dentate group and the edentulous group (χ2 = 5.68; p = 0.017). There was no group effect (F(29,648) = 0.849; p < 0.696; Wilks' lambda = 0.963). In the dentate group, the frequencies of APOE were: ɛ2 = 8.8%, ɛ3 = 77.9% and ɛ4 = 13.3%. Corresponding frequencies of APOE in the edentulous group were: ɛ2 = 6.6%, ɛ3 = 75.4% and ɛ4 = 18.0%.

    Conclusion: Despite matching both groups with regard to different background factors, the edentulous group had a higher frequency of APOE ɛ4 than the dentate group. Thus, genetic factors might contribute to greater risk in developing complex oral diseases leading to tooth loss or just be an indication that the subjects in our study carrying APOE ɛ4 are more fragile.

  • 4. Blomqvist, My
    et al.
    Ek, Ulla
    Stockholm University, Faculty of Social Sciences, Department of Special Education.
    Fernell, Elisabeth
    Holmberg, Kirsten
    Westerlund, Joakim
    Stockholm University, Faculty of Social Sciences, Department of Psychology.
    Dahlloö, Göran
    Cognitive ability and dental fear and anxiety2013In: European Journal of Oral Sciences, ISSN 0909-8836, E-ISSN 1600-0722, Vol. 121, no 2, p. 117-120Article in journal (Refereed)
    Abstract [en]

    Dental fear and anxiety (DFA), as well as dental behavior management problems, are common in children and adolescents. Several psychological factors in the child, and parental DFA, have been studied and found to correlate to the child's DFA. The aim of this study was to investigate the relationship between cognitive ability and DFA in a population-based group of children with identified behavior and learning problems. In conjunction with a dental examination at 11yr of age, 70 children were assessed with regard to DFA using the Children's Fear Survey Schedule Dental Subscale (CFSS-DS), and their cognitive ability was assessed using the Wechsler Intelligence Scale for Children. In addition, parental DFA was measured using the Corah Dental Anxiety Scale. The results revealed that DFA was significantly correlated to verbal intelligence quotient (IQ) but not to any other cognitive index. A significant correlation was found between parental DFA and child DFA. The results indicate that the child's verbal capacity may be one factor of importance in explaining dental fear in children.

  • 5.
    Brolinson, Annelie
    Stockholm University, Faculty of Science, The Wenner-Gren Institute .
    Regulation of Elovl and fatty acid metabolism2009Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Fatty acids are important regulators in the control of mammalian energy homeostasis. They are ingested in the diet but a significant amount are also endogenously produced by de novo lipogenesis. Fatty acid elongation beyond 16 carbons (palmitic acid) can occur to generate very long chain fatty acids (VLCFA), a process that is initiated by the rate-limiting condensation reaction. To date, six mammalian enzymes responsible for this reaction, ELOVL1-6 (Elongation of very long chain fatty acid), have been characterized. All of them exert substrate specificity and tissue-specific gene expression. In this thesis, factors that regulate fatty acid metabolism and, in particular, fatty acid synthesis and elongation will be presented.

    The enclosed papers discuss issues as to how Elovl3 is regulated in liver and in different adipose depots and what effects ablation of this enzyme causes to lipid homeostasis. Hepatic Elovl3 gene expression followed a circadian rhythm, present exclusively in sexually mature male mice. In contrast to the expression of several other lipogenic genes, Elovl3 gene expression was not affected by fasting or refeeding. Instead, the gene expression was influenced by steroid hormones such as glucocorticoids and sex hormones.

    Interestingly, despite reduced levels of leptin, Elovl3-ablated mice were shown to be resistant to diet induced weight gain, which seemed to be due to a decreased ratio between energy intake and energy expenditure. This phenotype was more pronounced in female mice.

  • 6. Jing, Zhao
    et al.
    Ke, Zhang
    Yihong, Liu
    Shen, Zhijian
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Effect of Multistep Processing Technique on the Formation of Micro-defects and Residual Stresses in Zirconia Dental Restorations2014In: Journal of Prosthodontics, ISSN 1059-941X, E-ISSN 1532-849X, Vol. 23, no 3, p. 206-212Article in journal (Refereed)
    Abstract [en]

    Purpose The clinical failures of zirconia dental restorations are often caused by extrinsic artifacts introduced by processing. The aim of this study was to investigate the micro-defects and residual stresses generated during the multistep process of zirconia dental restorations. Materials and Methods Thermal spray granulated 3Y-TZP powders were dry pressed by two tools exhibiting distinctly different Young's moduli, cold isostatic pressed (CIP-ed), and pressure-less fully sintered. The green bodies pressed by a stiff tool were treated with different procedures: direct milling (green milling) followed by fully sintering; half-sintering and milling (raw milling) with or without fully sintering; and fully sintering followed by grinding. The fully sintered 3Y-TZP crowns were clinically adjusted using both a diamond bur and SiC bur, respectively. Phase composition and microstructure of the pressed, milled, and ground surfaces were studied by XRD and SEM. Results Tetragonal phase was the main phase of all detected 3Y-TZP specimens. Excessive residual stresses introduced by raw milling and grinding were confirmed by a strained T (111) peak, monoclinic phase, and obviously changed I(002)(t)/I(200)(t) ratio. The residual stresses would form a compressive stress layer, while it was too shallow to inhibit crack propagation even for ground specimens. Large voids with high-coordination numbers were the common packing micro-defects. Once formed, they were barely healed by CIP-ing and sintering. A stiff pressing tool was confirmed to be useful for reducing the surface packing voids. Milling removed the surface voids, but was no help for the interior ones. Raw milling introduced more serious chippings, most originating from the existing packing voids, than green milling due to its brittle failure and was less recommended for production. Grinding dense 3Y-TZP caused surface grain refinement and much more severe micro-defects, especially when clinical adjustment was applied by diamond bur compared to SiC bur. Conclusions Micro-defects and residual stresses are introduced and accumulated through the entire production chain and determine the final microstructure of zirconia dental restorations. Several procedural improvements are offered and expected to reduce processing micro-defects.

  • 7.
    Kramarova, Tatiana
    Stockholm University, Faculty of Science, Wenner-Gren Institute for Experimental Biology.
    Limiting factors in ATP synthesis2006Doctoral thesis, monograph (Other academic)
    Abstract [en]

    The aim of the present study was to investigate the biosynthesis of the ATP synthase in various tissues, and to test hypotheses about possible models of activation of several mitochondrial proteins, the ATP/ADP translocase and UCPs, that could utilize the proton gradient, thus bypassing the ATP synthase.

    We have examined the role of the expression of the P1 isoform of the c-Fo subunit in the biogenesis of ATP synthase in brown adipose tissue. Our findings point to a role for the c-Fo subunit in defining the final content of the ATP synthase in brown adipose tissue.

    We have analyzed sequences in the 3’UTR of the β subunit F1-ATPase mRNA that are important for formation of RNA-protein complexes. We could detect protein complexes that bind to two different sequence regions of the 3’UTR, one being the poly(A) tail and an adjacent region), and the other being a sequence stretch at the 3’ end of the 3’UTR able to form a stem-loop structure, which is evolutionarily conserved throughout mammalian species.

    We investigated a role of the ATP/ADP carrier (ANT) in fatty acid-induced uncoupling in brown-fat mitochondria. We conclude that the ANT cannot substitute for UCP1 in fatty acid uncoupling in brown-fat mitochondria from mice lacking UCP1. We propose that the two ANT isoforms mediate proton translocation under different conditions.

    We have investigated a role of UCP1 in defence against oxidative stress. We found that products of oxidative stress (4-HNE) could neither reactivate purine nucleotide-inhibited UCP1, nor induce additional activation of innately active UCP1 in brown-fat mitochondria from UCP1(+/+) and UCP1(-/-) mice. We conclude that UCP1 is not involved in defence against oxidative stress.

    We evaluated possible uncoupling activity of UCP3 in skeletal muscle from warm- and cold-acclimated UCP1(+/+) and UCP1(-/-) mice. We conclude that no evidence exists for a higher UCP3-mediated uncoupling activity; a high UCP3 content in cold-acclimated UCP1(-/-) mice could possibly be linked to improved fatty acid oxidative capacity.

  • 8.
    Molnar, Petra
    Stockholm University, Faculty of Humanities, Department of Archaeology and Classical Studies, Osteoarchaeological Research Laboratory.
    Extramasticatory dental wear reflecting habitual behavior and health in past populations2011In: Clinical Oral Investigations, ISSN 1432-6981, E-ISSN 1436-3771, Vol. 15, no 5, p. 681-689Article in journal (Refereed)
    Abstract [en]

    In skeletal remains, teeth are valuable sources of information regarding age, diet, and health. Dental wear is especially helpful in reconstructions of dietary patterns in populations of varying subsistence. In past societies, teeth have also been used as a third hand or as a tool. The present article examines this type of dental wear and traits attributed to habitual behavior during prehistoric and historic times. Terminology and classification of habitual dental wear are described mainly by appearance, for instance, notching, grooving, cuts, scrapes, and polished surfaces, and their characteristics are illuminated by different case studies. Secondary health effects caused by the extramasticatory use of teeth, such as periapical lesions, tilting, skeletal changes at the temporomandibular joint, chipping, and antemortem tooth loss are also examined. During the examination of extramasticatory dental wear, information should be recorded on morphology, size, frequency, intensity, and location within the dental arch, as well as descriptions and detailed photographic documentation. The advantage of using a low-to medium-resolution microscope in all dental examination is emphasized. By categorizing the wear marks, characteristics are emphasized rather than an exact causing agent. In this way, tentative analogies for the origin of different extramasticatory wear, and consequently for human behavior in the past, can be avoided.

  • 9.
    Orban, Istvan
    et al.
    Stockholm University, Faculty of Science, Department of Physics.
    Tashenov, Stanislav
    Stockholm University, Faculty of Science, Department of Physics.
    Ferro, Fabrizio
    Stockholm University, Faculty of Science, Department of Physics.
    Lindroth, Eva
    Stockholm University, Faculty of Science, Department of Physics.
    Schuch, Reinhold
    Stockholm University, Faculty of Science, Department of Physics.
    Charge-state Selected Detection of Photons from Electron-Ion Interactions in an EBIT2009In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114Article in journal (Refereed)
    Abstract [en]

    A new approach provides charge-state selective recombination rate coefficients from TOF spectraof highly charged ions extracted from an EBIT. Experimentally derived dielectronic recombinationspectra are compared with results of relativistic many body perturbation theory calculations. Electronimpact excitation rate coefficients are also obtained from the experiment through the separationof the DR contribution in the X-ray spectra. The combination of TOF and X-ray measurementsoffers a powerful tool for the simultaneous extraction of atomic quantities for several charge states.

  • 10.
    Qian, Bin
    et al.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Saeidi, Kamran
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Kvetková, L.
    Lofaj, F.
    Xiao, Changhong
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Shen, Zhijian
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Defects-tolerant Co-Cr-Mo dental alloys prepared by selective laser melting2015In: Dental Materials, ISSN 0109-5641, E-ISSN 1879-0097, Vol. 31, no 12, p. 1435-1444Article in journal (Refereed)
    Abstract [en]

    Objectives. CrCoMo alloy specimens were successfully fabricated using selective laser melting (SLM). The aim of this study was to carefully investigate microstructure of the SLM specimens in order to understand the influence of their structural features inter-grown on different length scales ranging from nano-to macro-levels on their mechanical properties.

    Methods. Two different sets of processing parameters developed for building the inner part( core) and the surface (skin) of dental prostheses were tested. Microstructures were characterized by SEM, EBSD and XRD analysis. The elemental distribution was assessed by EDS line profile analysis under TEM. The mechanical properties of the specimens were measured.

    Results. The microstructures of both specimens were characterized showing formation of grains comprised of columnar sub-grains with Mo-enrichment at the sub-grain boundaries. Clusters of columnar sub-grains grew coherently along one common crystallographic direction forming much larger single crystal grains which are intercrossing in different directions forming an overall dendrite-like microstructure. Three types of microstructural defects were occasionally observed; small voids (<10 mu m), fine cracks at grain boundaries (<10 mu m) and cracks at weld line boundaries (>10 mu m). Despite the presence of these defects, the yield and the ultimate tensile strength (UTS) were 870 and 430 MPa and 1300 MPa and 1160 MPa, respectively, for the skin and core specimens which are higher than casted dental alloy.

    Significance. Although the formation of microstructural defects is hard to be avoided during the SLM process, the SLM CoCrMo alloys can achieve improved mechanical properties than their casted counterparts, implying they are defect-tolerant.

  • 11.
    Rapp, Mikaela
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    The Ins and Outs of Membrane Proteins: Topology Studies of Bacterial Membrane Proteins2006Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    α-helical membrane proteins comprise about a quarter of all proteins in a cell and carry out a wide variety of essential cellular functions. This thesis is focused on topology analyses of bacterial membrane proteins. The topology describes the two-dimensional structural arrangement of a protein relative to the membrane.

    By combining large-scale experimental and bioinformatics techniques we have produced experimentally constrained topology models for the major part of the Escherichia coli membrane proteome. This represents a substantial increase in available topology information for bacterial membrane proteins.

    Many membrane protein structures show signs of internal duplication and approximate two-fold in-plane symmetry. We propose a step-wise pathway to explain how proteins with such internal inverted repeats have evolved. The pathway is based on the ‘positive-inside’ rule and starts with a protein that can adopt two topologies in the membrane, i.e. a “dual” topology protein. The gene encoding the dual topology protein is duplicated and eventually, through re-distribution of positively charge residues, the two resulting homologous proteins become fixed in opposite orientations in the membrane. Finally, the two proteins may fuse into one single polypeptide with an internal inverted repeat structure.

    Finally, we re-create the proposed step-wise evolutionary pathway in the laboratory by showing that only a small number of mutations are required in order to transform the homo-dimeric, dual topology protein EmrE into a hetero-dimeric complex composed of two oppositely oriented proteins.

  • 12. Shahnavaz, Shervin
    et al.
    Hedman-Lagerlöf, Erik
    Hasselblad, Tove
    Reuterskiöld, Lena
    Stockholm University, Faculty of Social Sciences, Department of Psychology, Clinical psychology.
    Kaldo, Viktor
    Dahllöf, Göran
    Internet-Based Cognitive Behavioral Therapy for Children and Adolescents With Dental Anxiety: Open Trial2018In: Journal of Medical Internet Research, ISSN 1438-8871, E-ISSN 1438-8871, Vol. 20, no 1, article id e12Article in journal (Refereed)
    Abstract [en]

    Background: Cognitive behavioral therapy (CBT) is an evidence-based method for treating specific phobias, but access to treatment is difficult, especially for children and adolescents with dental anxiety. Psychologist-guided Internet-based CBT (ICBT) may be an effective way of increasing accessibility while maintaining treatment effects.

    Objective: The aim of this study was to test the hypothesis that psychologist-guided ICBT improves school-aged children’s and adolescents’ ability to manage dental anxiety by (1) decreasing avoidance and affecting the phobia diagnosis and (2) decreasing the dental fear and increasing the target groups’ self-efficacy. The study also aimed to examine the feasibility and acceptability of this novel treatment.

    Methods: This was an open, uncontrolled trial with assessments at baseline, posttreatment, and the 1-year follow-up. The study enrolled and treated 18 participants. The primary outcome was level of avoidance behaviors, as measured by the picture-guided behavioral avoidance test (PG-BAT). The secondary outcome was a diagnostic evaluation with the parents conducted by a psychologist. The specific phobia section of the structured interview Kiddie-Schedule for Affective Disorders and Schizophrenia for School-Age Children-Present and Lifetime (K-SADS-PL) was used. Other outcome measures included level of dental anxiety and self-efficacy. The ICBT, which employed exposure therapy, comprised 12 modules of texts, animations, dentistry-related video clips, and an exercise package (including dental instruments). Participants accessed the treatment through an Internet-based treatment platform and received Web-based guidance from a psychologist. Treatment also included training at dental clinics. Feasibility and acceptability were assessed by measures of engagement, adherence, compliance, completed measures, patient and parent satisfaction scale, and staff acceptability.

    Results: The level of avoidance (according to the primary outcome measure PG-BAT) and dental anxiety decreased and self-efficacy increased significantly (P<.001), within-group effect sizes for both the primary outcome (Cohen d=1.5), and other outcomes were large in the range of 0.9 and 1.5. According to K-SADS-PL, 53% (8/15) of the participants were free from diagnosable dental anxiety at the 1-year follow-up. At the 1-year follow-up, improvements were maintained and clinically significant, with 60% (9/15) of participants who had been unable to manage intraoral injection of local anesthetics before ICBT reporting having accomplished this task at a dental clinic. The target group showed improvement in all the outcome measures. High levels of feasibility and acceptability were observed for the treatment.

    Conclusions: ICBT is a promising and feasible treatment for dental anxiety in children and adolescents. Integrating it into routine pediatric dental care would increase access to an effective psychological treatment. The results of this open trial must be replicated in controlled studies.

  • 13.
    Wang, He
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Metabolic regulation of nitrogen fixation in Rhodospirillum rubrum2009Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Nitrogen, along with carbon, hydrogen and oxygen, is amongst the most abundant elements in all living cells. The capability to convert atmospheric dinitrogen to biologically usable nitrogen compounds is only found in some prokaryotes. Biological nitrogen fixation, the reduction of dinitrogen to ammonia, is the entry step into the global nitrogen cycle. Nitrogenase, the enzyme responsible for dinitrogen reduction, requires large amounts of ATP and reducing equivalents. Consequently, the nitrogen fixation process is subjected to sophisticated regulatory networks that respond to multiple environmental stimuli. In the free-living photosynthetic nitrogen-fixing bacterium Rhodospirillum rubrum, the activity of nitrogenase is tightly regulated at the post-translational level by reversible ADP-ribosylation in response to cellular changes in nitrogen and energy status, the so-called “switch-off” effect. Our studies have been focused on identifying the intracellular signal(s) and protein components acting during “switch-off”, and elucidating the mechanism underlying this regulation. We have shown that PII signal transduction proteins and the ammonium transporter AmtB1 play central roles in the signal transduction pathway leading to the post-translational regulation of nitrogenase, in particular, the involvement of AmtB1-PII complex formation during ammonium “switch-off”. In contrast, a different signaling pathway is operating during the energy “switch-off”, and several interesting differences are highlighted here. In addition, we have solved a high-resolution structure of Dinitrogenase Reductase Activating Glycohydrolase (DRAG) using X-ray crystallography. A detailed mechanism of ADP-ribose removal by DRAG is proposed, with our structural and functional studies on DRAG supporting a reversible membrane association mechanism of regulating its activity, further controlling the activity of nitrogenase.

  • 14. Weiner, Carina Kruger
    et al.
    Skalen, Maya
    Harju-Jeanty, Dick
    Heymann, Robert
    Rosen, Annika
    Fors, Uno
    Stockholm University, Faculty of Social Sciences, Department of Computer and Systems Sciences.
    Lund, Bodil
    Implementation of a Web-Based Patient Simulation Program to Teach Dental Students in Oral Surgery2016In: Journal of Dental Education, ISSN 0022-0337, E-ISSN 1930-7837, Vol. 80, no 2, p. 133-140Article in journal (Refereed)
    Abstract [en]

    The aim of this study was to evaluate a web-based simulation of patients (Web-SP) program on learning skills in clinical reasoning and patient evaluation in the oral surgery education of third-year dental students. A secondary aim was to investigate the program's effect on students' learning, knowledge, and attitudes towards virtual patient simulations. Authentic virtual oral surgery patient cases were created at a dental school in Sweden using the Web-SP platform. The Web-SP program was introduced in a two-hour seminar. A 20 -minute pre-seminar test (test A) was administered to assess the students' knowledge of oral surgery prior to experiencing the Web-SP program. Ten days after the seminar, another test (test B) was administered to evaluate the increase in oral surgery knowledge as a result of using the program, and an emailed survey of the students was conducted. Of 70 students in the course, 67 (95.7%) agreed to participate in the study and took test A; of these, 59 (88%) took test B. Of the 59 students who took both tests, 28 (42%) completed the survey. The results of the two tests showed a statistically significant increase in knowledge, which was in accordance with the learning goals (p<0.0001). The survey results showed that the students had a positive attitude towards the teaching method. In this study, Web-SP was found to be a valuable tool for teaching clinical reasoning and patient evaluation in an undergraduate oral surgery education setting by improving learning outcomes in comparison with traditional teaching alone.

  • 15.
    Westerlund, Kristina
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Exploring amino-acid radicals and quinone redox chemistry in model proteins2008Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Amino-acid radical enzymes have been studied extensively for 30 years but the experimental barriers to determine the thermodynamic properties of their key radical cofactors are so challenging that only a handful of reports exist in the literature. This is a major drawback when trying to understand the long-range radical transfer and/or catalytic mechanisms of this important family of enzymes. Here this issue is addressed by developing a library of well-structured model proteins specifically designed to study tyrosine and tryptophan radicals. The library is based on a 67-residue three-helix bundle (α3W) and a 117-residue four-helix bundle (α4W). α3W and α4W are single-chain and uniquely structured proteins. They are redox inert except for a single radical site (position 32 in α3W and 106 in α4W). Papers I and II describe the design process and the protein characteristics of α4W as well as a voltammetry study of its unique tryptophan. Paper III and V describe two projects based on α3C, which is a Trp-32 to Cys-32 variant of α3W. In Paper III we use α3C to investigate what effect the degree of solvent exposure of the phenolic OH group has on the redox characteristics of tyrosine analogs. We show that the potential of the PhO•/PhOH redox pair is dominated by interactions with the OH group and that the environment around the hydrophobic part of the phenol has no significant impact. In addition, we observe that interactions between the phenolic OH group and the protein matrix can raise the phenol potential by 0.11-0.12 V relative to solution values. The α3C system is extended in Paper V to study quinone redox chemistry. Papers III and V contain protocols to generate the cofactor-containing α3C systems and descriptions of their protein properties. Paper IV describes efforts to redesign α3Y (a Trp-32 to Tyr-32 variant of α3W) to contain an interacting Tyr-32/histidine pair. The aim is to engineer and study the effects of a redox-induced proton acceptor in the Tyr-32 site.

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