VictorJuiz/thesis huggingface dataset:
Synthesis, properties, and reactivity of silyl substituted allenylketenes

This thesis describes a study of the preparation and synthetic applications of silylallenyketenes. The synthesis of silylallenylketenes is described in Chapter 1. Allenylketenes, 32-36 and bis(allenylketene) 37 were generated by photolysis, of the corresponding alkylidenecyclobutenones in essentially quantitative yields. These allenylketenes are long-lived species at room temperature. The thermal interconversions of allenylketenes and alkyfidenecyclobutenones were studied. As predicted by ab intitio molecular orbital calculations, allenylketenes 32 and 36 undergo thermal equilibration with the corresponding alkylidenecyclobutenones 16 and 22 with equilibrium constants of 1.0 and 0.03, respectively, at 100°C. The X-ray structure of allenylketene 33 confirms the anti-periplanar conformation of the allenylketene as predicted by calculation. Allenylketenes 38 and 39 were generated by photolysis of alkylidenecyclobutenones 28 and 31, respectively, at -56°C. These allenylketenes were not stable at room temperature and converted back to the corresponding alkylidenecyclobutenones. The rates and activation parameters for the ring closure of allenylketenes, 36, 38, and 39 are reported. The reactivity of stable allenylketenes is described in Chapter 2. The reactions of allenylketenes with nucleophiles (water, methanol, and aniline) were studied. In the electrophilic reactions of the allenylketene, it was found that bromination, of allenylketene 16 was a 1,4 addition process and protonation of allenylketene 16 was a 1,2 addition process. Various cycloaddition reactions of allenylketenes were also studied. These reactions include [2 + 2] cycloadditions with acetaldehyde, [4 + 1] cycloadditions with trimethylsilyldiazomethane, [4 + 2] cycloadditions with tetracyanoethene, and a [4 + 2] cycloaddition between allenylketene 15 and benzaldehyde. Allenylketene 16 was found to react with a stable nitroxyl radical (TEMPO) to give the lactone 80. Finally, allenylketene 16 yielded silyl allenyl ketone 83 by reaction with 3-chloroperbenzoic acid.
A phylogenetic analysis of the Metazoa with special consideration of the Acanthocephala

The purpose of this study was to examine phylogenetic relationships among the Metazoa, identify appropriate outgroups to the Acanthocephala, and make a phylogenetic analysis of the Acanthocephala. A database of 144 characters for the metazoan phyla was obtained by examination of primary and secondary literature. The Choanoflagellata was used as outgroup for 33 multicellular phyla. Phylogenetic analysis yielded 17 equally parsimonious trees. Using successive weighting, these were reduced to two trees (Length = 361; CI = 0.46; HI = 0.58) differing only in placement of the Platyhelminthes. Monophyly of the Mesozoa was not supported but mesozoans were placed basal to the Porifera + (Cnidaria + (Ctenophora + remaining Metazoans)). The remaining Metazoans formed two major clades. The Acanthocephala was the basal member of a clade, the Ecdysozoa, containing Rotifera + (Gastrotricha + ((Nematoda + Nematomorpha) + (Pentastomida + (Kinorhynchida + (Tardigrada + (Onychophora + (Chelicerata + (Uniramia + Crustacea)))))))). The second clade consisted of two sub-clades; Chaetognatha basal to Chordata + (Echinodermata + (Phornida + Brachiopoda)) and Priapulida basal to Gnathostomulida + (Platyhelminthes + Nemertea + Mollusca + (Sipuncula + (Echiura + (Pogonophora + (Clitellata + Polychaeta))))). A novel approach to identification of early cleavage patterns involved coding of individual cleavage events as independent characters. Reinterpretation of the classic assignment of 'spiral' cleavage to arthropods supported placement within the Ecdysozoa. Deuterostomes were only monophyletic by including protostomes, thus 'spiral' cleavage is derived from 'radial' cleavage. The position of the Ecdysozoa as sister-group to the deuterostomes + protostomes supports the conclusion that 'modified-spiral' cleavage is not derived from 'spiral' cleavage. Priapulida and Rotifera were supported as outgroups for the analysis of relationships among the Acanthocephala. Direct examination of specimens identified 138 characters for 21 well-defined genera. Phylogenetic analysis yielded a single tree (Length = 404; CI = 0.545; HI = 0.455) which provided support for the monophyly of the Palaeacanthocephala and Eoacanthocephala but not the Archiacanthocephala, which were placed basal to the two other classes. To rectify taxonomic problems encountered while characters were being evaluated, 'Koronacantha', was described with a single species, ' K. mexicana'. 'Tegorhynchus brevis' was redescribed and 'T. pectinarius' transferred to 'Koronacantha'. Results supported placement of 'T. pectinarius' in ' Koronacantha' and retention of both 'Tegorhynchus' and 'Illiosentis' as distinct genera.
Hospital restructuring and process redesign, are we improving our health care systems?

Scarborough General Hospital (SGH) was faced with ongoing funding and bed reductions that resulted in the need to dramatically change the way in which it provided services. By utilizing SGH 's longitudinal database, selected external reviews and internal committee documentation, the effects of the hospital's organizational restructuring and process redesign on access, scope, financial viability, satisfaction and quality were investigated. Findings indicated the hospital's new organizational structure balanced the economy of a centralized model with the flexibility of a decentralized model. The chosen patient centered care delivery model was successful in achieving cross-functional teams, empowerment of staff, expanded roles for registered nurses and registered practical nurses and multi-skilling. Care pathways successfully reduced the length of stay and patient aggregations supported efficient delivery of care. The patient centered care approach brought selected services closer to the patient and maximized the efficient use of resources. The study indicated the hospital's change initiatives were pro-active, creative and effective. Patient's access to services was maintained, scope of services were expanded, measures remained within acceptable levels. The hospital also maintained financial stability and achieved one of the lowest "costs per case" in its peer group throughout the period of the review (1994/95-1997/98). The study identified the hospital's strategy of simultaneously layering multiple change projects, coupled with very aggressive time frames, failed to recognize staffs' need to achieve an appropriate learning curve. Insufficient time was available for staff to incorporate new learning into their personal paradigms and practice patterns. Better alignment of individual change strategies with the overall strategic plan was needed to ensure that the advantages gained would be sustainable. It was concluded that organizational redesign that is well managed over the long term can result in minimal disruption to patient care, maintained access to services and sustained quality of care. Factors identified as affecting successful change include stability of funding, commitment of adequate resources to support the change initiatives and ability to coordinate and link the individual change initiatives into the overall change design.
The biology and systematics of myxozoan parasites of fish and oligochaetes from Lake Sasajewun, Algonquin Park, Ontario

Since the discovery of the 2-host life cycle of myxozoans by Wolf and Markiw in 1984, numerous studies have contributed to the knowledge of myxozoan parasites, and at the same time, have raised even more questions. Most of these studies have only dealt with the experimental transmission of these parasites under laboratory conditions. In my dissertation, I have attempted to address some of the questions by looking at different aspects of these enigmatic parasites in a natural ecological setting. To fully document myxosporeans in Lake Sasajewun, a survey of these parasites of fish was conducted which resulted in the description of 2 new species. An intensive survey of oligochaete hosts of actinosporeans in the lake revealed that the fauna consisted of 19 species. Upon examining more than 14,000 worms for actinosporeans, only 146 worms were found to be releasing spores. Despite a prevalence of only 1.0%, 22 new 'species' of actinosporeans of 8 collective groups were described. The number of actinosporean 'species' is less than half the number of myxosporean species from the same lake, suggesting that direct transmission might occur among fish. Water-borne actinosporean spores peaked when water temperatures of the lake ranged from 18 to 24 C, which coincided with the feeding and growing season of larval fish. The molecular variation of 18 myxozoans from Lake Sasajewun was analyzed by riboprinting, revealing a close relationship between 'Myxobolus pendula' and 'Myxobolus pellicides', and between triactinomyxon 'C' and 'Triactinomyxon ignotum'. Parsimony analysis of riboprint data lent further support to the 2-host life cycle hypothesis. The genetic diversity of selected myxozoans was further investigated by sequence comparisons of the 18S rRNA gene. The phylogenetic hypothesis generated from the sequence data in this study and those available from GenBank also supported the alternating life cycle hypothesis. Phylogenetic analyses of the myxozoan species with known alternating life cycles, using morphological and developmental characters from myxosporean and actinosporean phases, were conducted through a total evidence approach. The analysis revealed that the suborder Variisporina and the family Myxobolidae were not monophyletic groups and that myxozoans were subject to thorough systematic revision.
Polychotomous logistic regression via the Lasso

The maximum likelihood method is traditionally used in estimating parameters in polychotomous logistic regression. The resulting estimates are known to have optimal theoretical properties in large samples but are prone to problems such as high variances in data multicollinearity, non-existence and small sample bias. In this thesis, alternative estimators for the polychotomous logistic regression are obtained via the Lasso. Lasso (Least Absolute Shrinkage Selection Operator) was invented by Tibshirani (1994) in the context of least squares regression. A defining characteristic of Lasso is its ability to produce parameter estimates which are identically equal to zero. A general Lasso model is proposed which involves shrinking all possible pairwise logits for each covariate in the model towards zero. Three realizations of the general model are considered, each motivated by a different data situation. Technical details necessary for the solving of the Lasso solutions and for fine-tuning the Lasso shrinkage are given. Approximate estimates of standard errors of the Lasso parameters are also proposed. An extensive simulation study is carried out to compare the performance of Lasso estimates to maximum likelihood estimates, as well as to Ridge estimates under a wide range of data situations. Finally, two Lasso polychotomous models are used to analyze two real life data sets.
A robust VSC-based shunt active power filter

This thesis is concerned with the development of a robust computer-controlled shunt active power filter for compensation of reactive power and harmonics in 3-phase 4-wire distribution systems. The proposed system consists of three independent single-phase filtering units. Each unit uses a current-controlled full-bridge voltage-source converter as the main device. The filter is controlled by a digital control system, which performs the following functions: load current harmonic and reactive component detection, dc voltage control, and current control. The harmonic and reactive components of the load current are detected in the frequency domain, using a sliding window DFT-based recursive algorithm. Therefore, each harmonic and reactive component of the load current is detected individually and the amplitude of each component of the compensation current is adjustable. A feedforward plus feedback control strategy based on the internal model control structure is developed for current and dc voltage control systems. Control is mainly achieved by feedforward. As a result, compensating actions in response to the line and load changes are executed with minimum time delay. Controllers are tuned based on the nominal values of the filter power circuit parameters, independently of the operating conditions. Performance of the proposed control systems is effectively insensitive to parameter uncertainties. Appropriate current limit algorithms are used to enable the filter to continue operation within its ratings, during and after transient disturbances in the line voltage or load current. An analysis of the active power filtering system considering the nonsinusoidal nature of the converter currents has been performed. Using a sampled-data model for the current control system, the reference tracking and disturbance rejection performance of the filter has been analyzed. A systematic design procedure has been presented, and a design example is provided. A C program has been developed to simulate the system operation. To test the feasibility of the proposed active filter, a 1.2 kVA experimental system has been set up in the laboratory. The control system is implemented using a TMS32040 DSP-based platform. The theoretical results have been verified by simulation and experiment.
Prior belief influences on reasoning and judgment, a multivariate investigation of individual differences in belief bias

Belief bias occurs when reasoning or judgments are found to be overly influenced by prior belief at the expense of a normatively prescribed accommodation of all the relevant data. The normative status and domain specificity/generality of belief bias was investigated in a multivariate investigation. The research reported here also examined the role of cognitive capacity and thinking dispositions on belief bias. Cognitive capacity deals with those parameters of interest to traditional tests of psychometric intelligence whereas thinking dispositions captures those parameters that deal with what can be thought of as the goals of the reasoner--how the capacities are put to use. A total of 124 participants recruited through an undergraduate university population participated in the study. Results suggested that belief bias is best interpreted as a nonnormative tendency in human reasoning and judgment. Furthermore, some moderate correlations among indices of belief bias across domains as varied as deductive reasoning and perceptual judgment suggest belief bias has some degree of domain generality. Finally, the results also suggest that both cognitive capacity and thinking dispositions account for some unique variance in belief bias. The results for this last finding, however, was moderated by the type of reasoning or judgments participants were asked to make.
Aqueous processing of rapeseed (canola)

A solvent-free system of extracting oil and protein from canola has been developed on a laboratory scale. The process consists of mechanical prepressing, aqueous extraction of most of the protein and oil, and subsequent purification by membrane processing to produce a high quality protein isolate, oil, a protein-lipid complex and a meal residue. Maximum extraction yields of more than 90% oil and 80% protein were obtained in the extraction process under optimum conditions: pH 11.0, 1:8 solid-to-water ratio, 22°C and two washing steps. Two protein products were obtained, an isolate with a protein content of about 90% and a protein-lipid complex in which the protein content can be varied from 30% to 60%. The two protein products account for 70% of the protein originally present in the seed. The extracted oil was recovered either in a lipid-protein complex or an emulsion phase. The total oil recovered represented from 90-96% of the oil originally present in the seed. The meal residue consisted mainly of hull and contained about 15% protein and 6% oil.
The effect of subtitled and staged video input on the learning and retention of content and vocabulary in a second language

This study investigates how grade 11 students of French as a second language in Ontario (N = 93) learn content and vocabulary in French with authentic video. Students in a Reversed condition watched a brief video documentary with English audio and French subtitles first (reversed format), then with French audio and French subtitles (bimodal format), and finally with French audio without subtitles (traditional format). Students in a Bimodal condition watched the same video in a bimodal format twice, followed by a traditional format, and students in a Traditional condition saw the video three times in a traditional format. Prior to the intervention, all students were assessed for general proficiency in French and prior vocabulary knowledge in order to control for initial differences. Content learning was measured by a Content test, and vocabulary learning by a Vocabulary Knowledge Scale (VKS) and a C-Cloze. The Content test and the C-Cloze were administered as immediate and delayed posttests, and the VKS was given as a pretest and a delayed posttest. Analyses of covariance revealed that the learning and retention of content in the Reversed and Bimodal conditions were similar and significantly superior to those in the Traditional condition. The learning and retention of vocabulary in the Bimodal condition were found to be significantly higher relative to the other two groups, whose outcomes were similar. Students' preferences for studying French with different kinds of input (text, sound and picture) were assessed in a Background Prequestionnaire. The majority of students in all conditions expressed a preference for reading (books and black-board), and for listening to the teacher (but not to audiotapes). Almost everybody who claimed attachment to watching video or TV (less than a quarter) was also reading-oriented. Students' input preferences did not affect significantly their performance on the tests, however. Finally, a Questionnaire given after treatment, revealed that students who were exposed to French subtitles reacted very positively to their use, and believed that the subtitles not only assisted their understanding of the video, but also helped them do the tests.
Controlled drug delivery using bioerodible polymeric systems for the treatment of periodontitis

Existing local drug delivery approaches for the treatment of periodontitis are; at times, unsatisfactory due to their rapid drug release and/or low biodegradability of the polymeric carrier. Bioerodible drug delivery systems may overcome these drawbacks and provide a more effective duration of treatment. In this study, bioerodible association polymer films were produced based on several blend ratios of cellulose acetate phthalate (CAP) and poly(oxyethylene co-propylene oxide) (Pluronic) at different metronidazole concentrations. After a systematic study of polymer erosion of the sample blends, a 30/70 (w/w) ratio of the CAP/Pluronic L101 blend was selected as the base for the peziodontal drug delivery device. These polymer films were evaluated for their thermal properties, association between CAP and L101, crystallinity, and stability at various humidity levels. A single glass transition temperature was observed on the differential scanning calorimetry thermograms for CAP/L101 blends, typical of miscible polymers. In the Fourier transform infra-red studies, the wavenumber of the CAP carbonyl band increased with the Pluronic content, demonstrating an association between CAP and L101 via hydrogen bonding. Increased crystallinity was noted for the 30/70 blends from the x-ray diffraction studies. Stability studies revealed that at 0 and 30% relative humidity, samples were stable for up to a month, while those stored at 100% relative humidity were not stable in terms of polymeric erosion and drug release rates. The polymer films and drug release profiles were characterized ' in vitro' (rotating disc apparatus), 'in vivo' (dorsal rat model), and in pilot clinical trials. It was established that both the drug release and polymer erosion rates decreased with increasing hydrophobicity of the Pluronic component. Similar erosion and drug release profiles were observed 'in vitro, in vivo' (animal model), and clinically, but varied in degree due to differences in their hydrodynamic conditions. After the first pilot clinical trial, the inserts were reformulated to produce 30/70 CAP/L101 periodontal inserts containing 2% (w/w) metronidazole. Analysis of the metronidazole concentration in the gingival crevicular fluid during subsequent clinical trials indicated a reduction in the drug burst effect along with prolonged drug release, yielding therapeutic drug concentrations for up to 4 days. The inserts were readily accepted by patients with no apparent adverse effects. These inserts are suitable for the localized treatment of periodontal infections.
The role of post-translationally modified myelin proteins in the mechanism of demyelination and the attenuation of disease by paclitaxel in the ND4 transgenic mouse

Recent findings on myelin proteins isolated from Multiple Sclerosis (MS) patients and an animal model for demyelinating disease (ND4 transgenic mice) suggest that the mechanism of disease begins prior to the activation of the immune system and involves an alteration in the post-translational modification of the major myelin proteins. This defect may be inherent in oligodendrocytes, the myelin producing cells in the central nervous system, and give rise to a developmentally immature myelin that is more susceptible to attack. Using the ND4 mouse, the biochemical synthesis of the myelin proteins proteolipid protein (PLP) and its splice variant (DM20 protein) was examined. No differences were observed between normal and ND4 mice at the DNA or RNA level but a change was detected in the post-translational modification. Isolation and characterization of PLP and DM20 proteins from ND4 mice demonstrated an increase in the amount of covalently bound palmitate and stearate. Using chemically hyperacylated PLP, increased levels of covalently bound palmitate were shown to reduce the Ã-helical content of PLP and promote its interactions with lipid within a bilayer. Thus an elevation in covalently bound fatty acids in PLP and DM20 could alter the stability of the myelin bilayer. Subsequently, myelin may become more susceptible to proteolytic digestion which in turn can digest myelin proteins to produce encephalitogenic peptides. In treating demyelinating disease, several steps within the mechanism of demyelination must be targeted. Pachitaxel, a drug which could potentially act at several steps, was injected into ND4 mice and was found to reduce the severity and progression of clinical signs, inhibit proliferating astrocytes, and promote remyelination in the ND4 mice. The findings reported in this thesis suggest one mechanism of demyelination which involves a defect in post-translational modification of myelin proteins, followed by formation of a less stable myelin and the response by other cells or components to this myelin. By targeting several different steps within this mechanism, paclitaxel was shown to be an effective drug in the treatment of demyelinating disease.