127 research outputs found
Automated Usability Testing Of Websites Using Link Structure
Websites keeps getting more important in business and other aspects of society. Making the websites as usable as possible is crucial as difficult to use systems tend to frustrate users, which might lead to users leaving or lost revenue for a business. Usability testing is needed to identify and fix those issues. Manual tests in usability labs can be very time consuming and costly. An automated system could reduce time and cost of testing, but are often too focused on one aspect to give a clear view of what needs to be fixed. A system to improve this is needed. 4 separate modules focusing on different aspects of testing the information structure and navigation of a website are implemented and tested. The modules are combined in a system that gather the results from each module and provide a better overview of the usability issues of a website
Fish farm ecology : a conceptual framework and empirical investigation of the CSR performance of Marine Harvest ASA and Cermaq ASA
The purpose of this master thesis is to give business participants, regulatory authorities, researchers and the broader community awareness of priority areas within the fish farming industry. In this sense, we have developed a conceptual framework; Fish Farm Ecology (FFE). The FFE model equates three spheres; economy, ecology, and ichthyology. It has flexibility and can be used both as an analytical tool for a broader interest group and as a management tool for companies within the industry. The conceptual framework and the empirical investigation are based upon five context areas; fish feed, sea cages, escaping, sea lice, and the slaughter process. In the empirical investigation, which is concentrated around two companies; Marine Harvest ASA and Cermaq ASA, perspectives of CSR and ethics are included. The CSR-FFE performance of Marine Harvest lies within the upper edge of a minor link, while Cermaq’s lies within the intermediate link
Biochemical characterization and DNA repair pathway interactions of Mag1-mediated base excision repair in Schizosaccharomyces pombe
The Schizosaccharomyces pombe mag1 gene encodes a DNA repair enzyme with sequence similarity to the AlkA family of DNA glycosylases, which are essential for the removal of cytotoxic alkylation products, the premutagenic deamination product hypoxanthine and certain cyclic ethenoadducts such as ethenoadenine. In this paper, we have purified the Mag1 protein and characterized its substrate specificity. It appears that the substrate range of Mag1 is limited to the major alkylation products, such as 3-mA, 3-mG and 7-mG, whereas no significant activity was found towards deamination products, ethenoadducts or oxidation products. The efficiency of 3-mA and 3-mG removal was 5–10 times slower for Mag1 than for Escherichia coli AlkA whereas the rate of 7-mG removal was similar to the two enzymes. The relatively low efficiency for the removal of cytotoxic 3-methylpurines is consistent with the moderate sensitivity of the mag1 mutant to methylating agents. Furthermore, we studied the initial steps of Mag1-dependent base excision repair (BER) and genetic interactions with other repair pathways by mutant analysis. The double mutants mag1 nth1, mag1 apn2 and mag1 rad2 displayed increased resistance to methyl methanesulfonate (MMS) compared with the single mutants nth1, apn2 and rad2, respectively, indicating that Mag1 initiates both short-patch (Nth1-dependent) and long-patch (Rad2-dependent) BER of MMS-induced damage. Spontaneous intrachromosomal recombination frequencies increased 3-fold in the mag1 mutant suggesting that Mag1 and recombinational repair (RR) are both involved in repair of alkylated bases. Finally, we show that the deletion of mag1 in the background of rad16, nth1 and rad2 single mutants reduced the total recombination frequencies of all three double mutants, indicating that abasic sites formed as a result of Mag1 removal of spontaneous base lesions are substrates for nucleotide excision repair, long- and short-patch BER and RR
Integrating mobile and web health infrastructures in low resource contexts
Trustworthy and accessible health information is a key success factor for health management at all levels of the health system in any country. There is a rapid growth in mobile penetration in Less-developed countries (LDC). This has lead to many projects that want to exploit this new infrastructure to collect health data from remote and rural areas in LDC.
This thesis addresses the dynamics of integrating mobile Short Message Service (SMS) infrastructures and web infrastructures in low resource contexts. The method chosen in this project is Action Design Research (ADR). Information infrastructure theory was utilized by strategies such as bootstrapping and cultivation of the existing installed base. These strategies were chosen to make the project sustainable. The project focuses on the use of existing mobile infrastructures, including private low-end phones of health workers, to collect health information in LDC. This ADR project consists of four phases, which includes two field trips to Uganda and Rwanda. Accordingly, background studies and analyzes of relevant installed bases in both countries have also been conducted. This ADR project has resulted in the development of a software artifact used to integrate the web-based system the District Health Information Software 2 (DHIS2) with the SMS infrastructure. This artifact has enabled remote data collection using SMS messages in the DHIS2. During this ADR project, we observed different kinds of dynamics when integrating the web and mobile infrastructures. We observed differences in flexibility in these two infrastructures. We also found that political and organizational processes increased the complexity involved in the process of integrating the two infrastructures.
Further, we observed that some users have experienced difficulties using SMS messaging for remote data collection in rural Uganda. Most importantly, we found that creation of a generative software artifact stimulates innovation. We also looked at how the process of integrating the two infrastructures can be interpreted in the terms of digital convergence.
Overall, this project has shown that it is possible to extend the boundaries of the web-based infrastructures by the integration with low resource mobile infrastructures. Hopefully, this project will contribute to the collection of more accurate health data from both remote and rural areas in low resource contexts
Systematiske litteratursøk til salgs: Ny tjeneste fra biblioteket
AbstractThe popularity of the review article as a publication type has increased dramatically during the last decades. As the number of single studies published each year has reached staggering heights, the need to summarize or synthesize these has proportionally increased. As one of their core services libraries throughout Norway provides access for their users to as much of the published research as possible. Unfortunately, that is not equivalent to enabling the users to locate relevant research. This is a challenge often requiring a special skill set and expertise in literature searching, both which is often found among specialized librarians. Requests from researchers at OsloMet – Oslo Metropolitan University (formerly Oslo and Akershus University College of Applied Sciences) for assistance from the librarians in performing systematic literature searches was the basis in developing the literature search service described in this article. How a typical request for a literature search is handled, what the product comprises and which aspects that will be prioritized in the future is expounded. Furthermore, the authors describe some of the experiences in launching this service as a service charging the researchers for librarian assistance on an hourly basis. Finally, challenges and unresolved issues are commented on.
Increased myocardial susceptibility to repetitive ischemia with high-fat diet-induced obesity.
Obesity and diabetes are frequently associated with cardiovascular disease. When a normal heart is subjected to brief/sublethal repetitive ischemia and reperfusion (I/R), adaptive responses are activated to preserve cardiac structure and function. These responses include but are not limited to alterations in cardiac metabolism, reduced calcium responsiveness, and induction of antioxidant enzymes. In a model of ischemic cardiomyopathy inducible by brief repetitive I/R, we hypothesized that dysregulation of these adaptive responses in diet-induced obese (DIO) mice would contribute to enhanced myocardial injury. DIO C57BL/6J mice were subjected to 15 min of daily repetitive I/R while under short-acting anesthesia, a protocol that results in the development of fibrotic cardiomyopathy. Cardiac lipids and candidate gene expression were analyzed at 3 days, and histology at 5 days of repetitive I/R. Total free fatty acids (FFAs) in the cardiac extracts of DIO mice were significantly elevated, reflecting primarily the dietary fatty acid (FA) composition. Compared with lean controls, cardiac FA oxidation (FAO) capacity of DIO mice was significantly higher, concurrent with increased expression of FA metabolism gene transcripts. Following 15 min of daily repetitive I/R for 3 or 5 days, DIO mice exhibited increased susceptibility to I/R and, in contrast to lean mice, developed microinfarction, which was associated with an exaggerated inflammatory response. Repetitive I/R in DIO mice was associated with more profound significant downregulation of FA metabolism gene transcripts and elevated FFAs and triglycerides. Maladaptive metabolic changes of FA metabolism contribute to enhanced myocardial injury in diet-induced obesity
Glucose-Insulin Therapy, Plasma Substrate Levels and Cardiac Recovery After Cardiac Ischemic Events
INTRODUCTION: The potential usefulness of glucose-insulin therapy relies to a large extent on the premise that it prevents hyperglycemia and hyperlipidemia following cardiac ischemic events. METHODS: In this review we evaluate the literature concerning plasma glucose and free fatty acids levels during and following cardiac ischemic events. RESULTS: The data indicate that hyperlipidemia and hyperglycemia most likely occur during acute coronary ischemic syndromes in the conscious state (e.g. acute myocardial infarction) and less so during reperfusion following CABG reperfusion. This is in accordance with observations that glucose-insulin therapy during early reperfusion post CABG may actually cause hypolipidemia, because substantial hyperlipidemia does not appear to occur during that stage of cardiac surgery. DISCUSSION: Considering recent data indicating that hypolipidemia may be detrimental for cardiac function, we propose that free fatty acid levels during reperfusion post CABG with the adjunct glucose-insulin therapy need to be closely monitored. CONCLUSION: From a clinical point of view, a strategy directed at monitoring and thereafter maintaining plasma substrate levels in the normal range for both glucose (4-6 mM) and FFA (0.2-0.6 mM) as well as stimulation of glucose oxidation, promises to be the most optimal metabolic reperfusion treatment following cardiac ischemic episodes. Future (preclinical and subsequently clinical) investigations are required to investigate whether the combination of glucose-insulin therapy with concomitant lipid administration may be beneficial in the setting of reperfusion post CAB
Assessment of Metabolic Phenotypes in Patients with Non-ischemic Dilated Cardiomyopathy Undergoing Cardiac Resynchronization Therapy
Studies of myocardial metabolism have reported that contractile performance at a given myocardial oxygen consumption (MVO2) can be lower when the heart is oxidizing fatty acids rather than glucose or lactate. The objective of this study is to assess the prognostic value of myocardial metabolic phenotypes in identifying non-responders among non-ischemic dilated cardiomyopathy (NIDCM) patients undergoing cardiac resynchronization therapy (CRT). Arterial and coronary sinus plasma concentrations of oxygen, glucose, lactate, pyruvate, free fatty acids (FFA), and 22 amino acids were obtained from 19 male and 2 female patients (mean age 56 ± 16) with NIDCM undergoing CRT. Metabolite fluxes/MVO2 and extraction fractions were calculated. Flux balance analysis (FBA) was performed with MetaFluxNet 1.8 on a metabolic network of the cardiac mitochondria (189 reactions, 230 metabolites) reconstructed from mitochondrial proteomic data (615 proteins) from human heart tissue. Non-responders based on left ventricular ejection fraction (LVEF) demonstrated a greater mean FFA extraction fraction (35% ± 17%) than responders [18 ± 10%, p = 0.0098, area under the estimated ROC curve (AUC) was 0.8238, S.E. 0.1115]. Calculated adenosine triphosphate (ATP)/MVO2 using FBA correlated with change in New York Heart Association (NYHA) class (rho = 0.63, p = 0.0298; AUC = 0.8381, S.E. 0.1316). Non-responders based on both LVEF and NYHA demonstrated a greater mean FFA uptake/MVO2 (0.115 ± 0.112) than responders (0.034 ± 0.030, p = 0.0171; AUC = 0.8593, S.E. 0.0965). Myocardial FFA flux and calculated maximal ATP synthesis flux using FBA may be helpful as biomarkers in identifying non-responders among NIDCM patients undergoing CRT
Schizosaccharomyces pombe Ofd2 Is a Nuclear 2-Oxoglutarate and Iron Dependent Dioxygenase Interacting with Histones
2-oxoglutarate (2OG) dependent dioxygenases are ubiquitous iron containing enzymes that couple substrate oxidation to the conversion of 2OG to succinate and carbon dioxide. They participate in a wide range of biological processes including collagen biosynthesis, fatty acid metabolism, hypoxic sensing and demethylation of nucleic acids and histones. Although substantial progress has been made in elucidating their function, the role of many 2OG dioxygenases remains enigmatic. Here we have studied the 2OG and iron (Fe(II)) dependent dioxygenase Ofd2 in Schizosaccharomyces pombe, a member of the AlkB subfamily of dioxygenases. We show that decarboxylation of 2OG by recombinant Ofd2 is dependent on Fe(II) and a histidine residue predicted to be involved in Fe(II) coordination. The decarboxylase activity of Ofd2 is stimulated by histones, and H2A has the strongest effect. Ofd2 interacts with all four core histones, however, only very weakly with H4. Our results define a new subclass of AlkB proteins interacting with histones, which also might comprise some of the human AlkB homologs with unknown function
Novel AlkB Dioxygenases—Alternative Models for In Silico and In Vivo Studies
Background: ALKBH proteins, the homologs of Escherichia coli AlkB dioxygenase, constitute a direct, single-protein repair system, protecting cellular DNA and RNA against the cytotoxic and mutagenic activity of alkylating agents, chemicals significantly contributing to tumor formation and used in cancer therapy. In silico analysis and in vivo studies have shown the existence of AlkB homologs in almost all organisms. Nine AlkB homologs (ALKBH1–8 and FTO) have been identified in humans. High ALKBH levels have been found to encourage tumor development, questioning the use of alkylating agents in chemotherapy. The aim of this work was to assign biological significance to multiple AlkB homologs by characterizing their activity in the repair of nucleic acids in prokaryotes and their subcellular localization in eukaryotes.
Methodology and Findings: Bioinformatic analysis of protein sequence databases identified 1943 AlkB sequences with eight
new AlkB subfamilies. Since Cyanobacteria and Arabidopsis thaliana contain multiple AlkB homologs, they were selected as model organisms for in vivo research. Using E. coli alkB2 mutant and plasmids expressing cyanobacterial AlkBs, we studied the repair of methyl methanesulfonate (MMS) and chloroacetaldehyde (CAA) induced lesions in ssDNA, ssRNA, and genomic DNA.
On the basis of GFP fusions, we investigated the subcellular localization of ALKBHs in A. thaliana and established its mostly nucleo-cytoplasmic distribution. Some of the ALKBH proteins were found to change their localization upon MMS treatment.
Conclusions: Our in vivo studies showed highly specific activity of cyanobacterial AlkB proteins towards lesions and nucleic acid type. Subcellular localization and translocation of ALKBHs in A. thaliana indicates a possible role for these proteins in the repair of alkyl lesions. We hypothesize that the multiplicity of ALKBHs is due to their involvement in the metabolism of nucleo-protein complexes; we find their repair by ALKBH proteins to be economical and effective alternative to degradation and de novo synthesis
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