15 resultados para higher alcohols

em Brock University, Canada


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Part I - Fluorinated Compounds A method has been developed for the extraction, concentration, and determination of two unique fluorinated compounds from the sediments of Lake Ontario. These compounds originated from a common industrial landfill, and have been carried to Lake Ontario by the Niagara River. Sediment samples from the Mississauga basin of Lake Ontario have been evaluated for these compounds and a depositional trend was established. The sediments were extracted by accelerated solvent extraction (ASE) and then underwent clean-up, fractionation, solvent exchange, and were concentrated by reduction under nitrogen gas. The concentrated extracts were analyzed by gas chromatography - electron capture negative ionization - mass spectrometry. The depositional profile determined here is reflective of the operation of the landfill and shows that these compounds are still found at concentrations well above background levels. These increased levels have been attributed to physical disturbances of previously deposited contaminated sediments, and probable continued leaching from the dumpsite. Part II - Polycyclic Aromatic Hydrocarbons Gas chromatography/mass spectrometry is the most common method for the determination of polycyclic aromatic hydrocarbons (PAHs) from various matrices. Mass discrimination of high-boiling compounds in gas chromatographic methods is well known. The use of high-boiling injection solvents shows substantial increase in the response of late-eluting peaks. These solvents have an increased efficiently in the transfer of solutes from the injector to the analytical column. The effect of I-butanol, I-pentanol, cyclopentanol, I-hexanol, toluene and n-octane, as injection solvents, was studied. Higher-boiling solvents yield increased response for all PAHs. I -Hexanol is the best solvent, in terms of P AH response, but in this solvent P AHs were more susceptible to chromatographic problems such as peak splitting and tailing. Toluene was found to be the most forgiving solvent in terms of peak symmetry and response. It offered the smallest discrepancies in response, and symmetry over a wide range of initial column temperatures.

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The implementation of chiral centres within biologically active compounds has been a perplexing yet motivational force in chemistry. This work presents the attempted formation of a concurrent or sequential tandem catalyzed methodology of enantioselective nucleophilic addition and electrophilic cyclization. The 2'- arylalkynyl- aldehyde, ketone, and imine substrates used within were adeptly chosen with a dually activated structure; 1) for nucleophilic addition to the electrophilic substituents; and 2) for carbophilic activation of the alkyne substituent to undergo cyclization. To accomplish the nucleophilic addition, two distinct allylation methodologies were pursued: (/?)-BINOL catalyzed-allylboration and (5)- BINAP-AgF catalyzed-allylsilylation. BINAP catalyzed enantioselective allylation of 2'-arylalkynyl-aldehydes, to form chiral homoallylic alcohols, was successful. Homoallylic alcohols were isolated with high enantio-purity (>80%), which then underwent sequential cyclization to form chiral allylic phthalans, in moderate yields. An application of this methodology towards the construction of biologically active compounds was included with the partial synthesis of the natural product and H. pylori inhibitor, (+)-Spirolaxine methyl ether.

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A general derivation of the anharmonic coefficients for a periodic lattice invoking the special case of the central force interaction is presented. All of the contributions to mean square displacement (MSD) to order 14 perturbation theory are enumerated. A direct correspondance is found between the high temperature limit MSD and high temperature limit free energy contributions up to and including 0(14). This correspondance follows from the detailed derivation of some of the contributions to MSD. Numerical results are obtained for all the MSD contributions to 0(14) using the Lennard-Jones potential for the lattice constants and temperatures for which the Monte Carlo results were calculated by Heiser, Shukla and Cowley. The Peierls approximation is also employed in order to simplify the numerical evaluation of the MSD contributions. The numerical results indicate the convergence of the perturbation expansion up to 75% of the melting temperature of the solid (TM) for the exact calculation; however, a better agreement with the Monte Carlo results is not obtained when the total of all 14 contributions is added to the 12 perturbation theory results. Using Peierls approximation the expansion converges up to 45% of TM• The MSD contributions arising in the Green's function method of Shukla and Hubschle are derived and enumerated up to and including 0(18). The total MSD from these selected contributions is in excellent agreement with their results at all temperatures. Theoretical values of the recoilless fraction for krypton are calculated from the MSD contributions for both the Lennard-Jones and Aziz potentials. The agreement with experimental values is quite good.

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This study addressed the problem of instructor support for self-directed learning, specifically, learner-directed program planning, within a classroom setting in higher education. A combination of survey, interview, document analysis, and observation was used to assess and evaluate the attitudes and practices of a sample of full-time faculty at an Ontario university. Eighty-seven percent of the study sample reported instructional beliefs, values, and expectations that were not supportive of self-directed learning, especially in terms of student participation in program planning. Planning was seen as the responsibility of the instructor. Instructors were least open to student participation in the planning of the evaluation of learning. However, there was considerable stated support for other of the basic principles of adult education. The remaining 13% of the study sample reported instructional beliefs, values, and expectations that were fully supportive of self-directed learning. Instructional practices were analyzed in relation to the instructors' stated beliefs. Although practices reflected, in many instances, instructors' statements of support, there were some significant discrepancies between apparent support for the concept of self-directed learning and actual classroom practice. Both beliefs and practice were compared to a research model of self-directed learning. Most instructors did not have a concept of self-directed learning as comprehensive as that described in the research model. Instructor support for self-directed learning was profoundly influenced by the university setting. It was concluded that more strenuous attempts to research, enhance, and promote instructional and institutional support for self-directed learning in higher education are warranted.

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The reaction of tris(pentafluorophenyl)phosphine [5] with the nucleophiles dimethyl formamide (DMF), hexamethylphosphoric triamide (HMPA), diethyl formamide (DEF), hexaethylphosphoric triamide (HEPA), hydrazine, N,N-dimethyl hydrazine (in presence and/or absence of KF), phenylhydrazine, ammonium hydroxide, formamide, aniline, sodium hydrogen sulfide, and hexaethylphosphorous triamide was investigated. The reaction of [5] with DMF and HMPA gave the same product, namely tris-[4-(N,N-dimethylamino)-2,3,5,6-tetrafluorophenyl]phosphine [12] but in higher yield in the case of HMPA. Compound (5] also reacted with DEF to give tris[4-(N,N-diethylamino)-2,3,5,6-tetrafluorophenyl] phosphine [14]. When [51 was treated with HEPA, it gave a mixture of bis(pentafluorophe~yl)-(N,N-diethylamino-tetrafluorophenyl)phosphine, pentafluorophenyl-bis-(N,N-diethylamino-tetrafluorophenyl)phosphine and tris (N,N-diethylamino-tetrafluorophenyl)phosphine. Treatment of [5] with aqueeus hydrazine solution in excess ethanol gave tris(4-hydrazo-2,3,4,6-tetrafluorophenyl)phosphine [1s1 in high yield while reaction with aqueous hydrazine led to C-P cleavage and production of tetrafluorophenyl hydrazine. With N,N-dimethyl hydrazine, [5] gave tris(4-N,N-dimethylhydrazine-2,3,5,6-tetrafluorophenyl) phosphine {20j. The latter could be obtained in higher yield and shorter reaction time, by the addition of KF. The reaction of compound {51 with phenylhydrazine in THF gave bis(pentafluorophe~yl)-4-S-phenylhydrazino- 2,3,5,6-tetrafluorophenyl phosphine [22] in low yield. Reaction of [5] with ammonium hydroxide in THF at high pressure in the presence of KF gave tris-~4-amino-2,3,5,6-tetrafluorophenyl)phosphine [25]. Similarly, formamide led to a mixture of (C6F4NHZ)3P, (C6F4NHZ)ZPC6FS, (C6F4NHZ)ZPC6F4NHCHO, and C6F4NHZP(C6Fs)(C6F4NHCHO). When [5] was treated with aniline, a mixture of mono-, di-, and tri-substituted products was obtained. Sodium hydrogen sulfide in ethylene glycol/ pyridine led to C-P cleavage and the isolation of pentafluorobenzene and tetrafluorothiophenol. Reaction of [5] and its oxide [35] with different alkoxides in the corresponding alcohols led mainly to C-P bond cleavage products, with the exception of one case where sodium methoxide was used in ether, and which led to tris-(4-methoxy-2,3,9,6-tetrafluorophenyl)phosphine [37]. On the basis of various spectroscopic data, it was concluded that the para position in compound [5] was generally the favoured site of attack.

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This is a study which examines the roles and responsibilities of Deans, specifically focussing on the Deans in the Faculties of Education at three Ontario Universities - Brock University, the University of Western Ontario, and the University of Windsor. This study examines the roles of Deans in the context of leadership and as a management position. The initial belief of the researcher was that Deans acted as middle managers at their institution besides being role models, scholars and leaders. Data were collected through interviews with the various participants and through the examination of the official job descriptions at each institution. Concepts such as leadership, motivation, empowerment, and management are discussed in relation to the position of Dean. The research concludes that a Dean is a leader in higher education who is responsible for a variety of issues. Besides academic related responsibilities such as faculty development, program development and research, a Dean is also responsible for a wide range of administrative tasks including financial management and obligations to external groups. As a role model and scholar, the Dean must ensure that all areas have sufficient energies devoted to them. This creates a heavy burden on Deans as they have a great deal of responsibilities to manage while still maintaining their role as a scholar. The researcher concludes that the position of Dean requires additional support from the institution. This support could be in an Associate Dean or an Executive Assistant with training and support mechanisms on an ongoing basis.

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This study explores how effectively current research assistantships impart research methods, skills, and attitudes; and how well those experiences prepare the next generation of researchers to meet the evolving needs of an ever-expanding, knowledge- based economy and society. Through personal interviews, 7 graduate student research assistants expressed their perceptions regarding their research assistantships. The open- ended interview questions emphasized (a) what research knowledge and skills the graduate students acquired; (b) what other lessons they took away from the experience; and (c) how the research assistantships influenced their graduate studies and future academic plans. After participants were interviewed, the data were transcribed, memberchecked, and then analyzed using a grounded theory research design. The findings show that research assistantships are valuable educational venues that can not only promote research learning but also benefit research assistants' master's studies and stimulate reflection regarding their future educational and research plans. Although data are limited to the responses of 7 students, findings can contribute to the enhancement of research assistantship opportunities as a means of developing skilled future researchers that in tum will benefit Canada as an emerging leader in research and development. The study is meant to serve as an informative source for (a) experienced researchers who have worked with research assistants; (b) researchers who are planning to hire research assistants; and (c) experienced and novice research assistants. Further, the study has the potential to inform future research training initiatives as well as related policies and practices.

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Despite the profound and widespread concern for the future of higher education physical education, there has been little systematic study on the topic. This research investigated the future by utilizing a two-round interview Delphi method. Five international experts were asked to project possible, probable, preferable and undesirable futures of the academic discipline in fifteen years time; specifically in regards to issues within the undergraduate degree programs, and the research sub-disciplines. The results of quantitative descriptive statistics and qualitative content analysis reveal an ever-changing higher education environment in the postmodern information age, which presents a complicating future for the academic discipline. The experts expressed concern that some disciplinarians will be a-futuristic and unable to operationalize the vast potential of the discipline at the institutional level, by continuing to use outdated and inappropriate frameworks of a modern era gone by.

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As institutions of higher education struggle to stay relevant, competitive, accessible, and flexible, they are scrambling to attend to a shift in focus for new students. This shift involves experiential learning. The purpose of this major research paper was to examine the existing structures, to seek gaps in the experiential learning programs, and to devise a framework to move forward. The specific focus was on experiential learning at Brock University in the Faculty of Applied Health Sciences. The methodology was underscored with cognitive constructivism and appreciative theory. Data collection involved content analysis steps established by Krippendorff (2004) and Weber (1985). Data analysis involved the four dimensions of reflection designed by LaBoskey, including the purpose, context, content, and procedures. The results developed understandings on the state of formal processes and pathways within service learning. A tool kit was generated that defines service learning and offers an overview of the types of service learning typically employed. The tool kit acts as a reference guide for those interested in implementing experiential learning courses. Importantly, the results also provided 10 key points in experiential learning courses by Emily Allan. A flow chart illustrates the connections among each of the 10 points, and then they are described in full to establish a strategy for the way forward in experiential learning.

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Scant research has explored how professors in Canadian universities use Twitter as a teaching tool or to augment knowledge about their subject disciplines. This case study employed a mixed-method approach to examine how professors in an Ontario university use Twitter. Using a variation of the technology acceptance model, the survey (n = 17) found that professor participants—41.2% of whom use Twitter—perceive Twitter as somewhat useful as a teaching tool, not useful for finding and sharing information, and not useful for personal use. Participants’ gender and number of years teaching are not indicators of Twitter use. Furthermore, the level of support from peers and the university may be reasons why some do not use Twitter or have stopped using Twitter. Face-to-face interviews (n = 3) revealed that Twitter is not used in classrooms or lecture halls, but predominantly as a means of sharing information with students and colleagues. Another deterrent to using Twitter is not knowing who to follow. Findings indicate that some professors at this university embrace Twitter, but not necessarily as an in-class teaching tool. The challenge and the advantage of using Twitter is to discover and follow people who tweet material and to select relevant material to pass along to students and colleagues. Professor participants in the study found a use for the social network as a means to increase student engagement, create virtual information-exchange communities, and enrich their own learning.

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The various forms of mentoring relationships in higher education have all proven to be valuable, offering numerous benefits to mentors and protégés. Research into mentoring provides critical insight into aspects of these relationships, which can be used to advance theoretical and practical understandings of the topic. However, little is known about the methodological characteristics of the mentoring research itself. Using descriptive quantitative content analysis, I examined five years of articles published in five scholarly journals to determine the prevalence of research about mentoring in higher education. Not surprisingly, the prevalence of these articles differed significantly among journals in higher education (1.07% to 3.13%) compared to the considerably higher prevalence rate of 53.15% for the mentoring journal, Mentoring & Tutoring [χ2 (4, N = 82) = 143.98, p < .01]. I also report findings related to the prevalence of different empirical research traditions, research designs, and data sources, as well as various populations, such as faculty members or graduate students who serve as mentors or protégés. Given the limited number of mentoring articles published in higher education journals, I was unable to compare methodological characteristics across journals. Implications for theory, research, and practice in the area of mentoring in higher education are also suggested. Understanding the methodological characteristics of the current literature allows researchers to tailor their current studies by either continuing with existing trends in methodological approaches or seeking opportunities to incorporate under-utilized research traditions, designs, or data sources, with the aim of continuing to improve mentoring knowledge and outcomes.

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This study examined the similarities and differences that currently exist between Chinese and Canadian online higher education, and explored the economic, political, and sociocultural environments that have shaped online education in these two jurisdictions. Furthermore, this paper discussed the efficacy of, and potential for, future development of online learning in higher education in both Canada and China. The research employed a collective case study design to gather information and data on the development of online higher education. The analysis on Contact North in Canada and the One-Man University in China provide a comparative perspective on the development of 2 typical online higher educational institutions in these two countries. The study revealed that the development of online higher education is influenced by the economic, political, and sociocultural factors of environment. Contact North and the One-Man University share similarities in many aspects, but are characteristically different. The Contact North can set an example for establishing and operating a self-regulated MOOCs platform. The study also generated implications for both organizations.

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Contraction-mediated lipolysis increases the association of lipid droplets and mitochondria, indicating an important role in the passage of fatty acids from lipid droplets to mitochondria in skeletal muscle. PLIN3 and PLIN5 are of particular interest to the lipid droplet–mitochondria interaction because PLIN3 is able to move about within cells and PLIN5 associates with skeletal muscle mitochondria. This study primarily investigated: 1) if PLIN3 is detected in skeletal muscle mitochondrial fraction; and 2) if mitochondrial protein content of PLIN3 and/or PLIN5 changes following stimulated contraction. A secondary aim was to determine if PLIN3 and PLIN5 associate and whether this changes following contraction. Male Long Evans rats (n = 21;age, 52 days; weight = 317 6 g) underwent 30 min of hindlimb stimulation (10 msec impulses, 100 Hz/3 sec at 10–20 V; train duration 100 msec). Contraction induced a ~50% reduction in intramuscular lipid content measured by oil red-O staining of red gastrocnemius muscle. Mitochondria were isolated from red gastrocnemius muscle by differential centrifugation and proteins were detected by western blotting. Mitochondrial PLIN5 content was ~1.6-fold higher following 30 min of contraction and PLIN3 content was detected in the mitochondrial fraction, and unchanged following contraction. An association between PLIN3 and PLIN5 was observed and remained unaltered following contraction. PLIN5 may play a role in mitochondria during lipolysis, which is consistent with a role in facilitating/regulating mitochondrial fatty acid oxidation. PLIN3 and PLIN5 may be working together on the lipid droplet and mitochondria during contraction-induced lipolysis.

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The article was published in the journal Meat Science, Vol. 46, No.4. The focus is data collected for cattle temperament and the quality of meat produced.