VictorJuiz/thesis huggingface dataset:
Charge microheterogeneity of myelin basic protein in murine brain

In murine brain, myelin basic protein represents a highly heterogeneous family of proteins consisting of several isoforms and charge isomers (or components). On alkaline-urea slab gels, murine MBP resolved into two major groups of isomers: the 18.5 (slow migrating group) and 14 kDa (fast migrating group) isoforms. Following isolation by CM-52 cation exchange chromatography, individual murine MBP components were characterized. Component 1 (C-1), the most cationic isomer, had a molecular weight of 14 140.38 $\pm$ 0.79 amu. C-2 consisted of two 14 kDa species; 14 136.37 $\pm$ 0.74 and 14 204.45 $\pm$ 0.70 amu. Species with molecular weights of 14 215.57 $\pm$ 0.94 and 18 413.57 $\pm$ 0.76 amu constituted C-3. The 14 and 18.5 kDa isoforms were also present in C-4, C-5 and C-8 (the least cationic isomer). Over the course of development, C-8 levels decreased whereas levels corresponding to the most cationic isomers for both the 14 and 18.5 kDa isoforms increased. These findings suggested that an increase in the production of the most cationic isomers is necessary for maturation of the myelin membrane. MBP isolated from the brains of natural mutant and transgenic mice was also characterized. The dysmyelinating shiverer mouse which carries a deletion of exons 3 to 7 in the MBP gene was unable to synthesize the major MBP isoforms. However, characterization of high-molecular weight proteins immunoreactive with anti-MBP antibodies suggested that golli-mbp may be present in shiverer brain. Studies on the transgenic shiverer mouse, which was generated by incorporation of a wild-type MBP transgene onto a shiverer background, demonstrated that (1) the 18.5 kDa isoform and corresponding isomers were the major MBP species and (2) charge microheterogeneity was similar to that of an early myelinating animal.
2-Ethylhexanol: A Potential Biological Indicator of Occupational Exposure to the Plasticizer di(2-Ethylhexyl)phthalate

The urinary metabolite 2-ethylhexanol (2-EH) was investigated as a potential biological indicator of occupational exposure to the plasticizer di(2-ethylhexyl) phthalate (DEHP). Urine and personal air samples were collected for 2.5 workshifts from seven plasticized resin workers and two controls. DEHP concentrations in workplace air were below 0.25 mg/m$\sp3$ (provincial limit 5 mg/m$\sp3).$ Airborne 2-EH, which was produced from heating DEHP, ranged from 0.92 to 4.5 mg/m$\sp3.$ Urinary 2-EH was determined by a new analytical method which used solid phase extraction of 2-EH followed by esterification with trichloro acetic anhydride and analysis by GC-ECD. The limit of detection was 0.01$\mu$g/ml. Urinary 2-EH in exposed workers generally increased following each workshift and ranged from undetected to 13.54$\mu$g/mmol creatinine. Analysis of the correlation between DEHP exposure and urinan, 2-EH was inconclusive due to the limited sample size of the study. Neither DEHP nor 2-EH (airborne or urinary) were detected in controls.
Distributed resource allocation for DS-CDMA-based multimedia wireless LANs

Next generation multi-media WLANs are expected to support a wide variety of applications with varying service requirements. It is the role of the resource management scheme to map the service requirements of the various applications to network resources so that the QoS requirements of the various users are met. ie. Given certain QoS constraints, what resources does the application require from the network such that the QoS requirements are met? Power control in DS-CDMA systems and more recently power/rate allocation in multi-rate DS-CDMA based networks is an open and interesting research area which has attracted a lot of attention. However, with a few exceptions, most researchers have emphasized centralized resource allocation algorithms for cellular systems where the base station keeps track of the requirements of the various users and is thus responsible for the management of network resources. Adhoc WLANs, on the other hand, are generally configured as peer-to-peer networks with no centralized hub or controller. Thus resource allocation has to be conducted in a distributed fashion. We address the issue of distributed resource management for multi-rate DS-CDMA based multi-media WLANs by: (1) Presenting a distributed resource allocation protocol known as Distributed Resource Negotiation Protocol (DRNP) which is geared towards negotiating QoS guarantees through receiver based distributed power control and bandwidth rationing in ad-hoc DS-CDMA based multi-media WLANs. (2) Investigating the performance of three resource allocation policies (minimum resource, maximum rate, maximum SIR) within the context of DRNP, in terms of network wide metrics such as blocking and loss of QoS rates. Surprisingly, the minimization of resources scheme which emphasizes conservation of transmission powers and yields the highest capacities in cellular (more generally centralized) networks, turned out to be the worst overall performer.
Discriminative fear conditioning to context expressed by multiple measures of fear in the rat

There has been a renewed interest in the neural basis of fear conditioning to context. These current approaches are accompanied by some limitations including the use of short testing windows, non discriminative paradigms, and unitary fear response assessment. In an attempt to circumvent these limitations, a discriminative context procedure assessing multiple response measures of fear was used in the present study. Conditioning consisted of three training sessions and each session consisted of two days. On day one the animals were placed in the paired context and received three foot shocks. On the other day they were placed in the unpaired chamber in the absence of any aversive event. Animals were tested after each training session and the responses measures of fear recorded included: preference, freezing, heart rate, ultrasonic vocalizations, defecation, body temperature, urination and locomotion. The results suggest that behavioral, as well as physiological changes evoked by fearful stimuli become associated with the context in which the aversive event occurred. In general these findings also suggest that there are different learning rate parameters for the measures of fear examined in this paradigm.
The effects of token status and gender-orientation of the task on participation, influence and emergent leadership behaviour in male-dominated and female-dominated work groups

The need to more effectively integrate men and women into group roles requires a fuller consideration of the dynamics of work-group diversity and specifically those factors that influence intra-group behaviour in mixed-gender work-teams. Drawing from theories of tokenism, social role and status characteristics, this study develops and tests a model that examines the influence of group gender composition and gender-orientation of the task on the behaviour of group members. Specifically, this study evaluates, via laboratory study, the effects of membership in male-dominated, female-dominated and balanced-gender work-groups on the levels of participation, degrees of influence and patterns of emergent leadership behaviour exhibited by male and female group members. In addition, this study draws specific attention to the notion of perceived status among group members based on congruence or incongruence with the gender-orientation of the task. The results of this study provide support for the central hypotheses of this thesis, including the view that a group member's numerical status (based on the relative representation of men and women in the group), along with the gender-orientation of the task, will have important implications for men and women regarding patterns of influence and emergent leadership behaviour exerted in the work-group. In addition, the findings of this study offer striking evidence that perceptions of relative status or expertise, based on congruence or incongruence with the gender-orientation of the task, can clearly affect intra-group behaviour. Specifically, male and female group members exhibited higher levels of participation and exerted greater levels of influence and emergent leadership behaviour when they performed group tasks that were stereotypically male-oriented and female-oriented respectively. On the other hand, group members who performed gender-incongruent tasks experienced decrements in the levels of participation, influence and leadership behaviour observed in the work-group.
Enhancement of entorhinal-dentate evoked potentials following repeated electroconvulsive shock seizures in the rat, neuroprotection studies

Burnham and colleagues have recently shown that repeated ECS long-lasting and perhaps permanent enhancement in entorhinal-dentate evoked potentials (EPs) in rats. These studies, however, involved "unmodified" ECS, whereas, in clinical practice, ECT is now given in its "modified" form. Experiment 1, therefore, repeated the study of Burnham et al. (1995) using "modified" ECS. Despite the use of the "modified" procedure, a significant and long-lasting (up to 3 months) enhancement in population spike amplitude was seen in the ECS group. Stewart and Reid (1994) have reported that ketamine protects against EP enhancement following "unmodified" ECS. Experiment 2 was designed to confirm and extend the findings of Stewart and Reid (1994). Despite the use of ketamine, a significant enhancement in population spike amplitude was seen in the ECS groups. The "therapeutic" effect of ECS, however, as indexed by the Porsolt test, was diminished in animals receiving either ketamine or PB.
DNA fragmentation in spermatozoa, implications for failed fertilization in intracytoplasmic sperm injection

Objectives. To correlate the percentage of sperm with damaged DNA with semen analysis parameters and with fertilization rates in ICSI. To evaluate the effect of exogenously generated reactive oxygen species (ROS) on the integrity of the DNA of human spermatozoa and the effectiveness of pretreatment with antioxidants to reduce DNA damage. Design. Semen samples were collected from men in the ICSI program at a tertiary-care centre. DNA fragmentation was determined using the method of TUNEL. Reactive oxygen species was generated in washed sperm samples in an attempt to cause DNA fragmentation. Antioxidants were added to 17 samples to determine if DNA damage could be prevented. Results. A negative correlation was found between the percentage of DNA fragmentation and motility and morphology of the ejaculated sperm. A significant negative association was also found between the percentage of sperm with DNA fragmentation and fertilization rate. When the unfertilized oocytes were analyzed, we determined that almost 25% contained sperm with fragmented DNA and 25% of the sample group demonstrated fragmented oocyte DNA. Lastly, we established that exogenous ROS can cause an almost fourfold increase in DNA damage which can be prevented by the addition of antioxidants. Conclusions. Since poor quality semen samples are the indication for ICSI, our results suggest that there is a greater likelihood that some sperm selected for injection despite appearing normal, contained fragmented DNA.
Methodology for the on-line design of identification experiments

In this thesis, system identification using the Frequency Sampling Filter (FSF) model is evaluated. A new input signal design method is developed specifically for application in industrial environments. Employing both the FSF model and the newly developed input signal design method, a methodology for the on-line design of identification experiments is proposed. The new input signal design method produces a multi-frequency, non-periodic signal with energy concentrated at prespecified frequencies. This method is easy to apply and, in comparison with other popular design methods, is shown to produce more accurate step response model estimates. Four parameters in the identification experiment are shown to act as indicators of data quality and model accuracy. Using these indicators as a basis, a set of guidelines is developed. The guidelines specify changes in the experimental conditions which are necessary to ensure that an accurate process model estimate is obtained. These guidelines are expanded into a methodology for on-line use during the identification experiment.
Fatty acid methyl ester analysis of microbial communities in biofilters inoculated with different sources

Biofiltration is an air pollution control technology which relies on the activity of a microbial community attached to the biofilter media for contaminant mineralization. The effect of the microbial inoculum source on the biofilter performance and the characterization of the microbial community using fatty acid methyl ester (FAME) analysis was experimentally studied. The experimental design included three parallel biofilters, each inoculated with a different source of microorganisms and run under equivalent conditions with air contaminated with $\alpha$-pinene, a hydrophobic volatile organic compound, (loading rates of 5 to 30 g $\alpha$-pinene/m$\sp3$ bed medium/h). Two experimental runs were performed and each run led to the same conclusions. Although the inocula had a significant effect on the acclimation time of the biofilter, the inocula did not have a great effect on the long term biofilter performance. The long term steady state removal rate was approximately 10 g $\alpha$-pinene/m$\sp3$ bed medium/h. Fatty acid methyl ester (FAME) analysis compares differences in microbial communities based on the type and distribution of fatty acids. Fatty acid profiles indicate that the inocula in each run were significantly different. However, background fatty acids from the wood based biofilter media caused interference and when the inocula were mixed with the media, the fatty acid patterns became similar. During the operation of the biofilters, when the $\alpha$-pinene degradation activity of the three biofilters were similar, differences in the fatty acid profiles of the three different biofilters were not detected. FAME analysis on a larger bench scale biofilter with the same media but a higher microbial biomass indicated differences in the fatty acid profiles which corresponded to differences in the $\alpha$-pinene degradation rate.
Immunological perspectives into a naturally arising tumor

Although there is evidence that immune responses are induced against tumors, the development of cancer in patients suggests that tumor immunity is not efficient in vivo. In our model, immune responses to a naturally arising pancreatic $\beta$-islet cell tumor are examined. This spontaneously arising tumor has a defined viral tumor antigen to which responses against the tumor could be measured. Proliferation assays suggested the absence of an anti-tumor response. Activating the immune response via virus infection generated anti-tumor T-cells, but the response was not sustained. The animal's lifespan was prolonged by the manipulations, but failed to eradicate the disease. The tumor antigen specific T-cells were found not to be tolerant. Furthermore, continued expression of the tumor antigen was observed. Current immunotherapies of cancer involve tumor cells engineered to secrete cytokines. Since in our model there is a defined tumor antigen peptide, peptide therapy could be used to induce and sustain an anti-tumor response.
Chip interleaving for CDMA cellular systems

We consider the forward link of a direct sequence CDMA cellular system operating in an environment with time varying multi-path fading and introduce a chip interleaving scheme. We study the probability of symbol error for various cases of the interleaving parameters for the cases of a one-path and a two-path Rayleigh fading channel. The chip interleaver output is combined with equal gain combining before the detector. Simulation results for the symbol error probability for each chip interleaving configuration and different interleaving degrees are obtained. Additionally, the effects of hard and soft decision decoding on the performance of the system are considered. The chip interleaving simulation results are compared to the symbol block interleaving used in the IS-95 CDMA cellular system standard. The results show that chip interleaving improves the performance of the CDMA link over that which is based solely on symbol interleaving.
Sources of stress in hockey referees

The major sources of stress in hockey officials were examined. 112 Ontario Soccer Officials' Surveys (modified for hockey officials) were completed and returned to the researcher. Results from this study are compared with previous studies involving soccer, football, volleyball, and baseball officials. Four main sources of stress emerged through a factor analysis of the results. These stressors were the factors of Interpersonal Conflicts, Fear of Physical Harm, Time Pressures, and Peer Conflicts. Suggestions for future research in this area are provided.
Expression of N-type calcium channel subunits in the developing rat hippocampus

Voltage-dependent calcium channels (VDCCs) are diverse heteromers that mediate neuronal excitability, neurotransmitter release, and contribute to the cytoarchitecture of the brain. One major VDCC--the N-type (N-VDCC), is thought to play a role in neurodevelopment, however the precise details are unknown. In this thesis, N-VDCC expression was investigated in the developing rat hippocampus, using antibodies to the $\rm\alpha\sb{1B},\ \beta\sb3$ and $\alpha\sb2/\delta$ subunits comprising the N-VDCC heteromer, and ($\sp{125}$I) -$\omega$-conotoxin GVIA binding assays. Binding showed increases in N-VDCCs during development, parallel to $\rm\alpha\sb{1B}$ subunit expression. However, the expression of $\beta\sb3$ and $\alpha\sb2$ subunits were different from that of the $\rm\alpha\sb{1B}$ subunit, suggesting that these subunits are not always coassembled. Immunoprecipitations indicated that coassembly of the $\beta\sb3$ subunit with $\rm\alpha\sb{1B}$ increases throughout development, however the proportion of $\rm\alpha\sb{1B}$-$\beta\sb3$ complexes in the total $\rm\alpha\sb{1B}$ pool varies. Thus, $\rm\alpha\sb{1B}$ may exist alone, or coassembled with $\beta$ subunits other than $\beta\sb3.$ The prenatal expression of N-VDCCs is consistent with a proposed role in neuronal migration, while their postnatal increase suggests a role in differentiation and synaptogenesis. These studies help define N-VDCC subunit expression in development, and may provide insight into channel functionality during critical developmental periods.
Influence of silica fume on chloride resistance of concrete

Deterioration of reinforced concrete structures is often related to corrosion of the reinforcement. For offshore structures and structures in cold climates, corrosion is mainly initiated by the penetration of chlorides. Many structures are not accessible or uneconomical to repair. Therefore, great care is required in designing new concrete structures for service in severe environments. The main consideration is to increase the chloride resistance of concrete. This thesis work investigates the influences of silica fume and W/CM ratio on the chloride resistance of concrete. Other factors studied were curing regimes and different coarse aggregates. The main tests used for evaluation were bulk diffusion tests, standard AASHTO T259 salt ponding test, and rapid chloride permeability test. 7% silica fume replacement was found to be more effective than reducing W/CM ratio from 0.45 to 0.35 in enhancing the durability of concrete. Good correlations between the different chloride penetration resistance tests were also established.
Closed-loop system identification with operator intervention

During a process identification experiment, it often occurs that the process output variable drifts outside the acceptable operating region due to process disturbances. In this situation, the operator will attempt to bring the process output variable back inside the desired operating region by adjusting the manipulated input variable. This thesis studies the effects of such operator intervention on the accuracy of the identification results and proposes the use of correct noise models in the design of a process input-output data prefilter to remove the resulting biasing effects. In addition, this thesis develops a modified generalized least squares algorithm to simultaneously estimate the process model and the noise model.
The relationship between physical activity and academic achievement in senior secondary school students

The problem investigated in this study is to determine if there is a significant relationship between physical activity and academic achievement in senior high school students. More specifically, does a moderate level of physical activity facilitate higher academic grades than those students who maintain relatively low or high levels of physical activity? An original questionnaire was created and administered to 126 grades 11, 12, and 13 students from one secondary school representative of the Greater Toronto Area. The data collected reflects the sample's academic achievement and physical activity level from their previous academic semester. All four of the hypotheses tested indicate no statistically significant results. The majority of the sample (46%) is measured to be in the moderate physically active range or level. The study's results confirm the conclusions of other studies, that physical activity does not hinder or deter a student's ability to succeed academically. (Abstract shortened by UMI.)
Interactions among the mitogen-activated protein kinase cascades and the identification of a novel cdc2-related protein kinase

Signal transduction is the means by which cells recognize and respond to changes in their external environment through the modification of cytoplasmic and nuclear events. In several cases, transduction of the signal to the nucleus of the cell occurs through cascades of protein kinases. In mammalian cells, structurally homologous mitogen-activated protein kinase (MAPK) cascades regulate diverse biological functions. This raises the question of how specificity is achieved in signalling via MAPKs. With the yeast two hybrid system, we reveal that the three known MAPK pathways, ERK, SAPK, and p38, do not require scaffolding proteins to maintain signalling specificity and that crosstalk among them does not readily occur in vivo. The cloning of a novel 67 kD cytoplasmic serine/threonine kinase is also described. This kinase, termed NKIATRE, is the third member of a unique family of kinases that are highly related to the MAPKs and the cyclin-dependent kinases.
An area efficient and high speed programmable digital biquad filter

This thesis presents an area efficient and high speed implementation of a $\Delta{-}\Sigma$ based biquad filter. This filter processes a 1-bit $\Delta{-}\Sigma$ modulated signal at an oversampled rate directly without downsampling and upsampling. To save area, the filter architecture uses only one simple ALU to perform all arithmetic for the filter. The implementation of the filter chip uses true-single-phase-clocking dynamic logic. TSPC logic is used to pipeline the filter at the complex-gate level, and improves the clock rate and throughput of the filter significantly. The filter chip has been sent to CMC to be fabricated in a 3-layer metal 0.8$\mu$m BiCMOS process. It occupies an area of $\rm3140\times3440\ \mu m\sp2.$ HSPICE simulations show that the filter should work at the clock rate of 660 MHz. At this clock rate, the filter can handle input at a maximum sampling rate of 18.3 MHz, corresponding to a bandwidth of 36.6 kHz with an OSR of 256.