753 research outputs found

    Kinetics determination of soybean oil transesterification in the design of a continuous biodiesel production process

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    One-step batch transesterification consisting of three stepwise reversible reactions of pure soybean oil with methanol was conducted at two different mixing speeds (600 and 300 rpm) to produce soybean oil fatty acid methyl esters (biodiesel). In both batch reactions, sodium methoxide (1.09 wt% based on soybean oil) was used as the catalyst, the reaction temperature was 60oC, and the methanol-to-oil molar ratio was 6:1. The objectives were to determine and/or investigate: 1) the mechanism and order of the reaction, 2) the reaction rate constants, 3) the effect of changes in mixing intensity on the reaction rate, 4) the comparison of the reaction mechanism and kinetic rate constants calculated with established literature references (for validation), and 5) how to interpret and utilize the kinetics analysis in the design of a continuous pilot-scale biodiesel production process. The kinetics analysis from the experiment showed that a second-order kinetic mechanism provided a good fit for the reaction. Kinetic rate constants at both mixing speeds were calculated and ranged from -3.10 x 10-3 - 0.028 (wt% min)-1 for the triglyceride, monoglyceride, and diglyceride forward reactions. The rate constants were slightly higher at the 600 rpm mixing speed. Higher mixing intensity also resulted in an increased purity of methyl esters (95.2 wt %). At both mixing speeds, monoglycerides showed the smallest percent elimination of all reaction intermediates at approximately 30%. The rate constants calculated for monoglycerides were the lowest as well. The monoglyceride rate constant of 0.0149 (wt% min)-1 was used in the design of a continuous process in a 100 gallon vessel, which is a scale of operation that could be easily adopted by a cooperative of oil seed producers or geographically isolated plant-oil producing villages. This Honors thesis was a component of a Biological and Agricultural Engineering team Senior Design project which consisted of designing a continuous biodiesel process from production to purification

    Embodying Embodied Design Research Techniques

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    The value of engaging the full gamut of sensory motor skills in the design and use of smart objects and systems is recognized. Yet methods for arriving at robust and reliable outcomes for their development are not fully understood, nor are they easily reported or transferred through typical conference presentations and paper submissions. New forms of knowledge transfer, such as pictorials (e.g., DIS and RTD conferences), and video are enabling enhanced, image-enriched reporting of outcomes. Y et appropriate transfer of embodied research methods remains elusive. In this workshop we propose to investigate how embodied research techniques may be used as direct and unmediated vehicles for their own reporting. Rather than engaging in oral presentations, participants will lead other participants through a proven embodied method or approach. Small groups will create mash-ups of techniques, exploring ways that the new approaches might coherently be reported. Participants will be encouraged to experiment with different recording techniques, including body-mounted sensing and recording devices, as well as less conventional approaches. The intention is to find appropriate ways of reporting embodied experiments, so that intangible elements are not lost. Participants will be supported to reflect on unfolding discoveries, to share impressions, as well as outcomes, including documentation experiments that aim to tangibly capture and communicate the processes undertaken. Embodied ideation, communication and collaboration techniques enable enhanced creative engagement and assist creativity [2]. By applying such methods to the problem of their reporting, we hope to deepen understanding of how to move towards enriched, nuanced and repeatable methods for embodied design and knowledge transfer. Crucially, our intention is not simply to find the next form of research reporting. Rather, this workshop will engage participants in an experimental enquiry, so that embodied design research may become an active area of inquiry moving forward.

    CW EPR investigation of red-emitting CaS:Eu phosphors: rationalization of local electronic structure

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    A series of commercial and prepared CaS:Eu2+ rare earth activated phosphors are investigated following different post‐synthetic treatments. A number of species directly related to the function of the material are characterized using electron paramagnetic resonance (EPR) spectroscopy. Isolated Eu2+ sites are identified and associated with the substitutional doping for Ca2+ in the lattice which are responsible for the 645 nm emission of interest. Another inactive Eu2+ site based within a “EuO” type phase aggregated on the surface of the material is also identified, as well as competitive F+ center defects that are known to reduce emission from the Eu2+ sites. Intrinsic Mn2+ impurities are identified and used as local order probes to determine changes in ordering and symmetry upon cryo‐milling and heating treatments of the samples. X‐ray photoelectron (XPS) and photoluminescence (PL) spectroscopies are also conducted to complement the local structure observations. The reported data is useful in understanding how the nature of the lattice affects ground state electronic structure of functional defective sites, for the development of efficient and selective materials

    PROCESS SCALE-UP AND OPTIMIZATION FOR PRODUCTION OF HIGH EFFICACY ORAL RABIES VACCINE

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    Rabies is an important causative agent of disease resulting in an acute infection of the nervous system and death of the individual. Rabies remains an important public health program in developing countries, and the indigenous threat of rabies continues in developed countries because of wildlife reservoirs. Globally, there are about 55,000 fatal human cases of rabies each year [WHO, 2007]. Control of rabies in wildlife remains an important challenge for government offices. There are numbers of rabies vaccines commercially available for controls of wildlife rabies. However, these vaccines currently distributed to wildlife do not effectively immunize all at-risk species, especially skunks. Alternative efficacious vaccines are needed. A human adenovirus rabies glycoprotein recombinant vaccine candidate (AdRG1.3), developed by the Rabies Research and Development Unit at Ontario Ministry of Natural Resources, Canada, has shown the most promising result in laboratory trials. The adenovirus used in rabies vaccine laden bait is produced using HEK 293 cell culture process. This presentation will focus on demonstrating the successful scale-up of AdRG1.3 adenovirus production from 1 liter to 500 liter to manufacture large quantities of bulk material required to support field trials and demonstrate efficacy of this new vaccine. The robustness of production process was improved through elimination of medium replacement operation at the time of virus infection, and culture titer was increased by over 3 folds through optimization of cell culture medium. The elimination of medium replacement step reduced the risk of culture contamination, and resulted in significant saving in material expenses and reduction in labor costs. Over 10,000 liters of active AdRG1.3 adenovirus cultures were manufactured so far to support field trials. AdRG1.3 adenovirus is formulated and packaged in baits using Artemis Technologies Inc. proprietary technology prior to aerial-baiting. AdRG1.3 rabies vaccine has been distributed by several provincial agencies to testing areas located in Ontario, Quebec and New Brunswick provinces, Canada, for field trials in yearly campaigns from 2006 to 2009. The field results showed that the new vaccine was more efficient than the existing ones in immunizing animals that were previously difficult to vaccinate

    Metabolic and Kinetic analyses of influenza production in perfusion HEK293 cell culture

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    <p>Abstract</p> <p>Background</p> <p>Cell culture-based production of influenza vaccine remains an attractive alternative to egg-based production. Short response time and high production yields are the key success factors for the broader adoption of cell culture technology for industrial manufacturing of pandemic and seasonal influenza vaccines. Recently, HEK293SF cells have been successfully used to produce influenza viruses, achieving hemagglutinin (HA) and infectious viral particle (IVP) titers in the highest ranges reported to date. In the same study, it was suggested that beyond 4 × 10<sup>6 </sup>cells/mL, viral production was limited by a lack of nutrients or an accumulation of toxic products.</p> <p>Results</p> <p>To further improve viral titers at high cell densities, perfusion culture mode was evaluated. Productivities of both perfusion and batch culture modes were compared at an infection cell density of 6 × 10<sup>6 </sup>cells/mL. The metabolism, including glycolysis, glutaminolysis and amino acids utilization as well as physiological indicators such as viability and apoptosis were extensively documented for the two modes of culture before and after viral infection to identify potential metabolic limitations. A 3 L bioreactor with a perfusion rate of 0.5 vol/day allowed us to reach maximal titers of 3.3 × 10<sup>11 </sup>IVP/mL and 4.0 logHA units/mL, corresponding to a total production of 1.0 × 10<sup>15 </sup>IVP and 7.8 logHA units after 3 days post-infection. Overall, perfusion mode titers were higher by almost one order of magnitude over the batch culture mode of production. This improvement was associated with an activation of the cell metabolism as seen by a 1.5-fold and 4-fold higher consumption rates of glucose and glutamine respectively. A shift in the viral production kinetics was also observed leading to an accumulation of more viable cells with a higher specific production and causing an increase in the total volumetric production of infectious influenza particles.</p> <p>Conclusions</p> <p>These results confirm that the HEK293SF cell is an excellent substrate for high yield production of influenza virus. Furthermore, there is great potential in further improving the production yields through better control of the cell culture environment and viral production kinetics. Once accomplished, this cell line can be promoted as an industrial platform for cost-effective manufacturing of the influenza seasonal vaccine as well as for periods of peak demand during pandemics.</p

    Exploiting the emergent nature of mixed methods designs: insights from a mixed methods impact evaluation in Malawi.

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    The application of mixed methods in Health Policy and Systems Research (HPSR) has expanded remarkably. Nevertheless, a recent review has highlighted how many mixed methods studies do not conceptualize the quantitative and the qualitative component as part of a single research effort, failing to make use of integrated approaches to data collection and analysis. More specifically, current mixed methods studies rarely rely on emergent designs as a specific feature of this methodological approach. In our work, we postulate that explicitly acknowledging the emergent nature of mixed methods research by building on a continuous exchange between quantitative and qualitative strains of data collection and analysis leads to a richer and more informative application in the field of HPSR. We illustrate our point by reflecting on our own experience conducting the mixed methods impact evaluation of a complex health system intervention in Malawi, the Results Based Financing for Maternal and Newborn Health Initiative. We describe how in the light of a contradiction between the initial set of quantitative and qualitative findings, we modified our design multiple times to include additional sources of quantitative and qualitative data and analytical approaches. To find an answer to the initial riddle, we made use of household survey data, routine health facility data, and multiple rounds of interviews with both healthcare workers and service users. We highlight what contextual factors made it possible for us to maintain the high level of methodological flexibility that ultimately allowed us to solve the riddle. This process of constant reiteration between quantitative and qualitative data allowed us to provide policymakers with a more credible and comprehensive picture of what dynamics the intervention had triggered and with what effects, in a way that we would have never been able to do had we kept faithful to our original mixed methods design

    Do Surgical Trials Meet the Scientific Standards for Clinical Trials?

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    Unlike medications, the dissemination of surgical procedures into practice is not regulated. Before marketing, pharmaceutical products are required to be shown safe and efficacious in comparative clinical trials that use bias-reducing strategies designed to reduce the distortion of estimates of treatment effect by predispositions toward the investigational intervention or control. Unless an investigational device is involved, the corresponding process for surgical innovations is usually unregulated and therefore may not be based on adequate evidence. Given these differences, we sought to evaluate the state of clinical research on invasive procedures. We conducted a systematic review of publications from 1999 through 2008, which reported the results of studies evaluating the effects of invasive therapeutic procedures, focusing on trials that appeared to influence practice. Our objective was to determine what proportion of studies evaluating surgical procedures use a comparative clinical trial design and methods to control bias. This article reports our results and raises concerns about the methodologic, and therefore the ethical, quality of clinical research used to justify the implementation of surgical procedures into practice

    RNA polymerase II synthesizes antisense RNA in Plasmodium falciparum

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    The recent identification of antisense RNA in the transcriptomes of many eukaryotes has generated enormous interest. The presence of antisense RNA in Plasmodium falciparum, the causative agent of severe malaria, remains controversial. Elucidation of the mechanism of antisense RNA in P. falciparum synthesis is critical in order to demonstrate the origin and function of these transcripts. Therefore, a systematic analysis of antisense and sense RNA synthesis was performed using direct labeling experiments. Nuclear run on experiments with single-stranded DNA probes demonstrated that antisense RNA is synthesized in the nucleus at several genomic loci. Antisense RNA synthesis is sensitive to the potent RNA polymerase II inhibitor α-amanitin. Antisense and sense transcription was also detected in nuclei isolated from synchronized parasites, suggesting concurrent synthesis. In summary, our experiments directly demonstrate that antisense RNA synthesis is a common transcriptional phenomenon in P. falciparum, and is catalyzed by RNA polymerase II. Copyright © 2005 RNA Society

    Delirium in Hospitalized Elderly Patients and Post-Discharge Mortality

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    OBJECTIVE: To determine the impact of delirium on post-discharge mortality in hospitalized older patients. INTRODUCTION: Delirium is frequent in hospitalized older patients and correlates with high hospital mortality. There are only a few studies about its impact on post-discharge mortality. METHODS: This is a prospective study of patients over 60 years old who were hospitalized in the Geriatric Unit at Hospital das ClĂ­nicas of SĂŁo Paulo between May 2006 and March 2007. Upon admission, demographics, comorbidities, number of drugs taken, and serum albumin concentration were evaluated for each patient. Delirium was diagnosed according to the DSM-IV criteria. Patients were divided into group A (with delirium) and group B (without delirium). One year after discharge, the patients or their caregivers were contacted to assess days of survival. RESULTS: The sample included 199 patients, 66 (33%) of whom developed delirium (Group A). After one year, 33 (50%) group A patients had died, and 45 (33.8%) group B patients had died (p = 0.03). There was a significant statistical difference in average age (p = 0.001) and immobility (p <0.001) between groups A and B. There were no statistically significant differences between groups A and B in number of drugs taken greater than four (p = 0.62), sex (p = 0.54) and number of diagnoses greater than four (p = 0.21). According to a multivariate analysis, delirium was not an independent predictor of post-discharge mortality. The predictors of post-discharge mortality were age > 80 years (p = 0.029), albumin concentration < 3.5 g/dl (p = 0.001) and immobility (p = 0.007). CONCLUSION: Delirium is associated with higher post-discharge mortality as a dependent predictor
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