5,105 research outputs found

    Local pre-processing for node classification in networks : application in protein-protein interaction

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    Network modelling provides an increasingly popular conceptualisation in a wide range of domains, including the analysis of protein structure. Typical approaches to analysis model parameter values at nodes within the network. The spherical locality around a node provides a microenvironment that can be used to characterise an area of a network rather than a particular point within it. Microenvironments that centre on the nodes in a protein chain can be used to quantify parameters that are related to protein functionality. They also permit particular patterns of such parameters in node-centred microenvironments to be used to locate sites of particular interest. This paper evaluates an approach to index generation that seeks to rapidly construct microenvironment data. The results show that index generation performs best when the radius of microenvironments matches the granularity of the index. Results are presented to show that such microenvironments improve the utility of protein chain parameters in classifying the structural characteristics of nodes using both support vector machines and neural networks

    Improved Tissue-Based Analytical Test Methods for Orellanine, a Biomarker of Cortinarius Mushroom Intoxication.

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    Orellanine (OR) toxin is produced by mushrooms of the genus Cortinarius which grow in North America and in Europe. OR poisoning is characterized by severe oliguric acute renal failure, with a mortality rate of 10%-30%. Diagnosis of OR poisoning currently hinges on a history of ingestion of Cortinarius mushrooms and histopathology of renal biopsies. A key step in the diagnostic approach is analysis of tissues for OR. Currently, tissue-based analytical methods for OR are nonspecific and lack sensitivity. The objectives of this study were: (1) to develop definitive HPLC and LC-MS/MS tissue-based analytical methods for OR; and (2) to investigate toxicological effects of OR in mice. The HPLC limit of quantitation was 10 Āµg/g. For fortification levels of 15 Āµg/g to 50 Āµg/g OR in kidney, the relative standard deviation was between 1.3% and 9.8%, and accuracy was within 1.5% to 7.1%. A matrix-matched calibration curve was reproduced in this range with a correlation coefficient (r) of 0.97-0.99. The limit of detection was 20 ng/g for LC-MS/MS. In OR-injected mice, kidney OR concentrations were 97 Ā± 51 Āµg/g on Day 0 and 17 Ā± 1 Āµg/g on termination Day 3. Splenic and liver injuries were novel findings in this mouse model. The new tissue-based analytical tests will improve diagnosis of OR poisoning, while the mouse model has yielded new data advancing knowledge on OR-induced pathology. The new tissue-based analytical tests will improve diagnosis of OR poisoning, while the mouse model has yielded new data advancing knowledge on OR-induced pathology

    Entrepreneurship Education: Engineering a Pracademic Approach

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    Innovation and entrepreneurship are becoming increasingly important as we rely on economies to create jobs around the globe. And yet, considering the myriad and dynamic business environments of the 21st century and ever increasing consumer power, the risk of entrepreneurial activity has increased considerably. Consequently, we need to educate engineers in an innovative manner and fundamentally change the teaching methods, curriculum, and research in entrepreneurship education. Applying the scholarship of teaching and learning (SoTL) to entrepreneurship with similar rigor can increase the odds of being successful engineering entrepreneurs. Still, faculty and administrators of engineering programs are hesitant to introduce courses into an engineering curriculum outside of engineering fundaments. The paradox, however, is that non-core engineering courses including leadership and engineering management can help students develop highly desired attributes that contribute to career and industry success. In this paper, the authors look at current trends in entrepreneurship education and will propose a potential new approach to innovation and entrepreneurship education for engineers in the 21st century. This approach will focus on pracademic (practical / professional and academic) learning concepts that are both engaging and worthwhile for student-centered learning. Supplementary pedagogical approaches are necessary to augment classroom learning for aligning active-learning topics within innovative course frameworks. This new approach will focus on four topics: innovation in teaching methods, introducing leadership education into the entrepreneurship curriculum, quality within systems engineering management, and using rigorous research to drive transformational change in entrepreneurship education. The pracademic approach will be taught as a workshop series or as courses in the entrepreneurship domain and will be presented as part of this paper where methods, leadership, quality, and rigorous research are the central tenets the authors propose for serious and thrivable consideration

    Solar powered micrometeorite sensors using indoor ambient light for the International Space Station

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    Sensors for detecting micrometeorite impact locations and magnitudes as well as pressure vessel leaks have been under investigation for some time by the NASA Langley Research Center and other related entities. NASA has been investigating the use of the Distribution Impact Detection System (DIDS) for use on the International Space Station (ISS). However, the DIDS currently requires thionyl chloride lithium batteries which pose explosion and toxicity hazards, and replacing batteries is tedious and utilizes scarce man-hours. Carrying replacement batteries into space is also expensive. To hardwire new sensing devices into the ISS while in orbit would be time consuming. To overcome this problem, high efficiency GaAs solar cells have been studied under low light conditions comparable to those found inside the ISS. The cells were also studied for temperature dependence. Solar concentrators were investigated for possible use with ambient lighting. The power generated by the cells was stored in a large 300 F supercapacitor. A DC to DC boost regulator was modified to produce an output voltage of 3.55 V that is required by the DIDS. The successful operation of the DIDS with ambient light power, supercapacitor energy storage, and boost regulation was demonstrated

    Update on the Talent aortic stent-graft: A preliminary report from United States phase I and II trials

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    AbstractPurpose: Phase I and phase II trials were conducted to determine the safety and efficacy of the Talent aortic stent-graft (Medtronic World Medical, Sunrise, Fla) in the treatment of infrarenal abdominal aortic aneurysms (AAA). This is a preliminary report of the technical results and 30-day clinical outcome of these trials. Methods: Multicenter prospective trials were conducted to test the Talent stent-graft in high-risk and low-risk patient populations with AAA, including phase I feasibility and phase II clinical trials. The low-risk study included concurrent surgical controls. Results: In the phase I trial, deployment success was achieved in 92% (23/25 patients), and initial technical success was 78% (18/23 implants without endoleak). The 30-day technical success rate was 96%, with six endoleaks that resolved spontaneously (without need for further intervention); and the 30-day mortality rate was 12% (3/25 patients). The phase II high-risk trial demonstrated a deployment success of 94% (119/127 patients) and an initial technical success of 86% (102/119 implants). The 30-day technical success rate was 96%, and the 30-day mortality rate was 1.5% (2/127 patients). The phase II low-risk trial included a first-generation and a second-generation Talent stent-graft. Deployment success rates were 97% and 99%, respectively, and technical success rates at 30 days were 97% and 96%, respectively. The 30-day mortality rate was 2% in the phase II low-risk first-generation device trial, and the adverse-event rate was 20%. Corresponding figures for the second-generation device were 0% and 1.8%, respectively. Conclusion: The Talent stent-graft can be deployed successfully and achieves endovascular exclusion in a large proportion of patients with AAA. Morbidity and mortality rates are acceptable. One-year clinical results and the comparison with concurrent surgical control subjects remain to be evaluated. (J Vasc Surg 2001;33:S146-9.

    Phosphofructokinase 1 Glycosylation Regulates Cell Growth and Metabolism

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    Cancer cells must satisfy the metabolic demands of rapid cell growth within a continually changing microenvironment. We demonstrated that the dynamic posttranslational modification of proteins by O-linked Ī²-N-acetylglucosamine (O-GlcNAcylation) is a key metabolic regulator of glucose metabolism. O-GlcNAcylation was induced at serine 529 of phosphofructokinase 1 (PFK1) in response to hypoxia. Glycosylation inhibited PFK1 activity and redirected glucose flux through the pentose phosphate pathway, thereby conferring a selective growth advantage on cancer cells. Blocking glycosylation of PFK1 at serine 529 reduced cancer cell proliferation in vitro and impaired tumor formation in vivo. These studies reveal a previously uncharacterized mechanism for the regulation of metabolic pathways in cancer and a possible target for therapeutic intervention
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