2,539 research outputs found
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Waveform-level time-domain simulation comparison study of three shipboard power system architectures
Detailed waveform-level modeling and simulation of three alternative shipboard power system architectures is presented herein. The three system architectures are based on conventional 60Hz medium-voltage ac (MVAC), higherfrequency 240Hz medium-voltage ac (HFAC) and mediumvoltage dc (MVDC) technologies. To support the quantitative assessment and comparison of these three different power system architectures, each technology was modeled using a common representative, notional baseline ship. The baseline ship represents a multi-mission destroyer fitted with an 80MW next generation integrated power system (NGIPS). Modeling of each power system architecture is set forth along with simulation studies for three fault scenarios. Each of the three power system architectures was implemented within the MATLAB/ Simulink environment. Continuity of service was evaluated for each architecture along with a fault scenario using an operability metric. After a brief description of the three power system architectures and the operability metric, quantitative results are presented.Center for Electromechanic
Telemedicine strategic planning and implementation issues in the Navy Medical Department
Telemedicine is a system of health care delivery which combines image, video, sounds and text, enabling health care providers to consult one another and to examine patients at a distance through the use of telecommunications technology. There are currently a number of telemedicine initiatives within the Department of Defense (DoD) designed to improve the delivery of health care within the military health services system. Telemedicine demonstration projects and consultation sites have been deployed at Army, Navy, and Air Force medical treatment facilities. These initiatives have been driven by recent advances in telecommunications technology, digital imaging technology and video teleconferencing (VTC) technology, coupled with pressures to reduce health care costs and improve access to scarce medical specialist resources. This thesis provides a contextual framework for the analysis of the potential effects of telemedicine on the Navy health care delivery system. The analysis is developed through the review of current telemedicine and telecommunications technology, examination of strategic planning and implementation issues facing Navy telemedicine efforts, and an assessment of the merits and problems associated with implementing a telemedicine pilot project in a Navy medical treatment facility.http://archive.org/details/telemedicinestra1094535124NANAU.S. Navy (U.S.N.) author
Harmonic assessment based adjusted current total harmonic distortion
Power systems suffer from harmonic distortion and extra ohmic losses associated with
them. Moreover, all harmonic frequencies are mostly assumed to have the same effect on the system losses. However, the frequency-dependency of the resistances should be taken into account, so that the apparent power and the power factor have to considerably reflect power losses under nonsinusoidal conditions. In this paper, the difference between unweighted and weighted non-sinusoidal losses, is addressed. A new harmonic-adjusted total harmonic distortion definition is proposed for
both voltage and current. Besides, a new formula that relates the proposed harmonic-adjusted total harmonic distortion and a generalised harmonic derating factor definition of the frequency dependent losses of the power transmission and distribution equipment, is derived. An optimal C-type passive filter design for harmonic mitigation and power factor correction based on the minimisation of the proposed harmonic-adjusted total harmonic distortion for a balanced nonsinusoidal system is introduced. A comparative study of the proposed filter design based on the new harmonic-adjusted definition, and a conventional filter design based on standard total harmonic distortion definition, is presented
Gaps in Adolescent Tobacco Prevention and Counseling in Vermont
Introduction. Tobacco use remains the leading cause of preventable death in Vermont. While the Vermont Blueprint for Health includes compensation for adult tobacco counseling, it includes no specific mention of pediatric populations. Research questions: To what extent are tobacco assessment and cessation efforts occurring in the primary care setting with pediatric patients? What factors influence their practices?Methods. A 12-question electronic survey, modeled on an American Academy of Pediatrics survey, was distributed to primary care providers throughout Vermont; through the UVM departments of pediatrics, family medicine, the Vermont Medical Society and the Vermont Area Health Education Center. We received 70 completed surveys.Results. 70% of the surveyed primary care providers begin tobacco counseling at the age recommended (11 years) by the Vermont Department of Health. Only 45.71% of providers are confident in their understanding of the recommendations for adolescent health screening written in the Blueprint for Health. Additionally, only 67.1% of the providers expressed confidence in their ability to provide guidance regarding the harmful effects of E-cigarettes, compared to 92.8% feeling confident regarding conventional cigarettes. 70% of providers listed time restraints as a significant factor in their decision not to counsel adolescents on tobacco use.Discussion. The Blueprint for Health is a guiding document for provider practices that is not well understood and does not specifically include pediatric tobacco prevention. In an environment where youth E-cigarette use is rising, especially among adolescents, it is especially critical that physicians are confident in their counseling practices.https://scholarworks.uvm.edu/comphp_gallery/1237/thumbnail.jp
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1,8-cineol potentiates IRF3-mediated antiviral response in human stem cells and an ex vivo model of rhinosinusitis
Common cold is one of the most frequent human inflammatory diseases caused by viruses and can facilitate bacterial super-infections resulting in sinusitis or pneumonia. The active ingredient of the drug Soledum, 1,8-cineole, is commonly applied for treating inflammatory diseases of the respiratory tract. However, the potential of 1,8-cineole for treating primary viral infections of the respiratory tract remains unclear.
In the present study, we demonstrate for the first time that 1,8-cineole potentiates Poly(I:C)-induced activity of the anti-viral transcription factor Interferon Regulatory Factor 3, while simultaneously reducing pro-inflammatory NF-κB-activity in human cell lines, inferior turbinate stem cells (ITSCs) and ex vivo cultivated human nasal mucosa. Co-treatment of cell lines with Poly(I:C) and 1,8-cineole resulted in significantly increased IRF3 reporter gene activity compared to Poly(I:C) alone, whereas NF-κB-activity was reduced. Accordingly, 1,8-cineole- and Poly(I:C)-treatment led to increased nuclear translocation of IRF3 in ITSCs and a human ex vivo model of rhinosinusitis compared to the Poly(I:C)-treated approach. Nuclear translocation of IRF3 was significantly increased in ITSCs and slice cultures treated with LPS and 1,8-cineole compared to the LPS-treated cells mimicking bacterial infection. Our findings strongly suggest that 1,8-cineole potentiates the antiviral activity of IRF3 in addition to its inhibitory effect on pro-inflammatory NF-κB-signalling and may thus broaden its field of application
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HPV & head and neck cancer: a descriptive update.
The incidence of head and neck squamous cell carcinoma (HNSCC) has been gradually increasing over the last three decades. Recent data have now attributed a viral aetiology to a subset of head and neck cancers. Several studies indicate that oral human papillomavirus (HPV) infection is likely to be sexually acquired. The dominance of HPV 16 in HPV+ HNSCC is even greater than that seen in cervical carcinoma of total worldwide cases. Strong evidence suggests that HPV+ status is an important prognostic factor associated with a favourable outcome in head and neck cancers. Approximately 30 to 40% of HNSCC patients with present with early stage I/II disease. These patients are treated with curative intent using single modality treatments either radiation or surgery alone. A non-operative approach is favored for patients in which surgery followed by either radiation alone or radiochemotherapy may lead to severe functional impairment. Cetuximab, a humanized mouse anti-EGFR IgG1 monoclonal antibody, improved locoregional control and overall survival in combination with radiotherapy in locally advanced tumours but at the cost of some increased cardiac morbidity and mortality. Finally, the improved prognosis and treatment responses to chemotherapy and radiotherapy by HPV+ tumours may suggest that HPV status detection is required to better plan and individualize patient treatment regimes.RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are
Dynamic model tracking design for low inertia, high speed permanent magnet ac motors
Permanent magnet a
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Culture bag systems for clinical applications of adult human neural crest-derived stem cells
Introduction
Facing the challenging treatment of neurodegenerative diseases as well as complex craniofacial injuries such as those common after cancer therapy, the field of regenerative medicine increasingly relies on stem cell transplantation strategies. Here, neural crest-derived stem cells (NCSCs) offer many promising applications, although scale up of clinical-grade processes prior to potential transplantations is currently limiting. In this study, we aimed to establish a clinical-grade, cost-reducing cultivation system for NCSCs isolated from the adult human nose using cGMP-grade Afc-FEP bags.
Methods
We cultivated human neural crest-derived stem cells from inferior turbinate (ITSCs) in a cell culture bag system using Afc-FEP bags in human blood plasma-supplemented medium. Investigations of viability, proliferation and expression profile of bag-cultured ITSCs were followed by DNA-content and telomerase activity determination. Cultivated ITSCs were introduced to directed in vitro differentiation assays to assess their potential for mesodermal and ectodermal differentiation. Mesodermal differentiation was determined using an enzyme activity assay (alkaline phosphatase, ALP), respective stainings (Alizarin Red S, Von Kossa and Oil Red O), and RT-PCR, while immunocytochemistry and synaptic vesicle recycling were applied to assay neuroectodermal differentiation of ITSCs.
Results
When cultivated within Afc-FEP bags, ITSCs grew three-dimensionally in a human blood plasma-derived matrix, thereby showing unchanged morphology, proliferation capability, viability and expression profile in comparison to three dimensionally-cultured ITSCs growing in standard cell culture plastics. Genetic stability of bag-cultured ITSCs was further accompanied by unchanged telomerase activity. Importantly, ITSCs retained their potential to differentiate into mesodermal cell types, particularly including ALP-active, Alizarin Red S-, and Von Kossa-positive osteogenic cell types, as well as adipocytes positive in Oil Red O assays. Bag culture further did not affect the potential of ITSCs to undergo differentiation into neuroectodermal cell types coexpressing β-III-tubulin and MAP2 and exhibiting the capability for synaptic vesicle recycling.
Conclusions
Here, we report for the first time the successful cultivation of human NCSCs within cGMP-grade Afc-FEP bags using a human blood plasma-supplemented medium. Our findings particularly demonstrate the unchanged differentiation capability and genetic stability of the cultivated NCSCs, suggesting the great potential of this culture system for future medical applications in the field of regenerative medicine
Spotlight on Using Mentor Texts in Writing Instruction: Turning to Books for Ideas
Researchers have found a connection between reading and writing instruction and the benefits the instruction has on students’ reading comprehension and writing expression. The purpose of this action research study was to explore the effectiveness of the use of mentor texts on the writing of 22 students in grade 3. Curricular methodology consisted of selected trade books used as mentor texts to represent the various genres and natural language structures inherent within children’s books so that students had consistent models of good writing as they attempted to emulate various authors’ styles of writing. Data collection consisted of a teacher-made questionnaire and teacher-created pre and post writing assessments for sentence construction and paragraph writing. Additionally, rubrics evaluated the quality of student writing. The study indicated that the use of mentor texts for writing instruction, taken together with a writers’ workshop approach, was an effective means for supporting student writing in genres inclusive of opinion, informational, and narrative writing. As students acquired the tools for becoming proficient writers, they wrote with excitement, confidence, and independence. The findings confirmed the theory that the use of mentor texts increased the quality of student writing; subsequently, students made the transition from genre writing to apply the skills across the curriculum
Effects of cognitive processing and cell phone use while driving
With 233 million cell phone subscribers in the United States at the end of the year 2006, and 73% of those subscribers talking on their cell phones while driving, the issue of safety on the roads has become a major one. While there has been widespread research on the causes of driver distraction, and comparisons among those causes, there has not been research conducted in order to evaluate the effects of visual imagery on driver performance. This research employed two types of programs to examine the response time to the presented stimuli, as well as missed targets among 16 subjects. For each program, subjects completed six tasks (Baseline, Mental Arithmetic, Directions, Synonyms, In Person Conversation, Cell Phone Conversation). In the stimulus-response program, subjects were asked to press certain keys on a keyboard, corresponding to the stimuli presented on the screen (The six trials in this program included simple response of space bar upon stimulus; selecting a, s, d, or f; selecting a, s, d, f, j, or k; selecting a, s, d, f, j, k, l, or ; ; selecting a, s, d, or f with a 75% more likely; selecting a, d, j, or k incompatible). In the driving video program, subjects were asked to press r or w when a red or white/silver car as soon as they perceived a car of that color to be approaching in the opposite lane. Upon analysis of the stimulus-response program, it was found that Task and Trial Type were significant, with three of the tasks (cell phone conversation, in-person conversation, and synonyms) were highly significantly different from the directions and mental arithmetic tasks. Upon analysis of the driving video program, it was found that Task was a significant factor for missed targets. In conclusion, it was found that tasks involving mental imagery were significantly different than tasks requiring simple communication
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