VictorJuiz/thesis huggingface dataset:
The influence of resin chemistry on a composite's inherent biochemical stability

Studies have shown that inflammatory and salivary enzymes can degrade bis-phenyl glycidyl dimethacrylate (bisGMA) and triethylene glycol dimethacrylate (TEGDMA), two dental composite resin components. In other work, commercial composite resins containing a urethane modified bisGMA-TEGDMA (u-bis) based monomer showed a 10-fold reduction in the release of bisGMA derived product, bis-hydroxy-propoxyphenyl propane (bisHPPP), as compared with that found for bisGMA-TEGDMA (bis) based composites. These observations have motivated the further study of interactions between composites and enzymes. Photopolymerized model composite resin samples based on bis or u-bis resins were incubated in pseudocholinesterase (PCE), cholesterol esterase (CE) or both, and in the presence of a specific esterase inhibitor, phenylmethylsulfonyl fluoride (PMSF), for 16 and 32 days (pH 7.0 at 37°C). Degradation rates for the monomers were assessed for each enzyme. Incubation solutions were analyzed for resin degradation products by high performance liquid chromatography (HPLC), UV spectroscopy and mass spectrometry. The composite surfaces were characterized by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The vinyl group conversion was characterized by Fourier transform infra red spectroscopy (FT-IR). Hydrolase activity in human saliva was analyzed and compared to stock enzymes. The results showed that both enzymes degrade the composite in a dose dependent manner. In the presence of CE, the u-bis system showed a 15 to 180 (depending on the specific product) fold decrease in the amount of isolated products relative to the bis system. SEM analysis confirmed the relative degradation levels. CE showed a greater ability to cleave bisGMA monomer while PCE showed more specificity towards TEGDMA. Addition of PMSF inhibited the degradation process, confirming the implication of the serine active site in the enzymes. Saliva was found to contain CE and PCE-like hydrolase activity, at levels that could degrade composite resins. The study suggests that the level of degradation products generated for a material will be dependent on the esterase make-up for an individual's saliva and the specific formulation of monomer components. Since resin formulation has a significant effect on the composite's chemical stability, manufacturers should consider testing biochemical stability as part of their routine product evaluation.
Fluid dynamics in magma chambers with application to sulphide settling

Experiments involving mica particles and a glycerol-water mixture were designed to study the mechanisms of sulphide settling and to determine the location of the settled sulphides with respect to the chamber geometry. In addition, the influence of the injection of different masses of fluid into an existing chamber on the already established pattern of settling has been investigated. The results suggest that convective flow in a high viscosity environment enhances settling of the sulphides. The largest accumulation of particles occurs directly above the heat source caused by a shear force exerted along the floor, increase in the vertical boundary thickness or downflow of the injected denser fluid that transports the particles away from the walls. The experiment confirmed that the sedimentation pattern is influenced by viscosity. Since a portion of the particles concentrated at the interface between convection cells, accumulations of the disseminated sulphides might be found throughout an intrusion.
Body Mass Index as a predictor of morbidity and mortality following lung transplantation

Limited data are available on the relationship between Body Mass Index (BMI) and morbidity and mortality in lung transplant populations. The objective of this study was to measure the association between post-transplant morbidity and mortality and preoperative BMI in end stage lung disease (ESLD). Dependent measures included Mortality at 90 days and 1 year post- transplantation; length of time in the Intensive Care Unit; length of time in the hospital; and, number of rejection episodes. Patients were grouped by BMI categories: <17 kg/m 2; 17 to <20 kg/m2; 20 to 25 kg/m2; >25 to 27 kg/m2; and, >27 kg/m2. The results indicated that patients with a pre-transplant BMI <17 kg/m2 showed a trend to increased mortality following transplantation (p = 0.085). Patient with a BMI >27 kg/m2 had a significant increase in mortality (p = 0.003). In conclusion, a pre-transplant BMI >27kg/m 2 was found to be a predictor of morbidity and mortality in ESLD patients post-transplantation.
DNA single strand breaks and cell survival in ME180 and SiHa cells irradiated at intermediate oxygen concentrations, effects of BSO treatments

The relationship between radiation sensitivity, oxygen concentrations and sulfhydryl status was investigated in two human cervical squamous carcinoma cell lines, ME180 and SiHa. Glutathione and cysteine levels were monitored using HPLC in controls and cells treated with DL-buthionine-[S,R]-sulfoximine (BSO) and were found to be regulated differently in these two cell lines. Cell suspensions were irradiated at a range of oxygen concentrations and the radiosensitivity was assessed using two endpoints: survival was determined using a clonogenic assay and the amount of initial DNA single strand breaks (DNA SSB) was determined using the alkaline comet assay. The results of this study demonstrate that (1) the effects of BSO on NPSH levels are cell line specific, (2) the levels of NPSH are influenced by the conditions under which the cells are incubated and (3) treatment with BSO results in distinct cell survival and initial DNA SSB profiles in ME180 and SiHa cells.
Preferences of patients undergoing angiogram for participation in treatment decisions, coping style and the Problem Solving-Decision Making Scale

Although current ideology suggests patients should be active participants in decision-making about their care, the literature suggests patients wish to be informed, but not involved. We studied preferences of 300 cardiac patients for information and involvement, and the influence of their coping style. We developed a reliable instrument based on the Deber-Baumann (1989) hypothesis that choice can be subdivided into "problem-solving" (one right answer) and "decision-making" (preferences for outcomes matter) tasks. Our key findings were that most patients: (1) want to be informed; (2) do not want to be involved in problem-solving; (3) want to be involved in decision-making; (4) are more inclined to hand control over to physicians in situations involving risk of mortality than those involving morbidity or quality of life. (5) Coping style was correlated with information desired and with patient preferences for some (but not all) decision-making tasks, but not with preferences for problem-solving tasks.
Oral storytelling and student learning, once upon a classroom

This study explores oral storytelling learning in the elementary school setting. The specific focus was on nine grade four classrooms at two urban public elementary schools. One hundred and eighty two students were involved in the study. As part of a community based arts program, a professional storyteller worked with each class over a three session period. The effect of oral storytelling on the students and the teachers is examined. Although, students engage in personal oral storytelling in their daily interactions with others, being exposed to and learning how to tell oral tales is an experience not readily available. Students often are only exposed to story reading. Being examined are the children, their teachers and the storyteller.
Teacher belief systems towards computer-mediated language learning, college ESL instruction

This research surveyed college-level English-as-a-Second instructors to define the nature of second language teacher belief systems towards computer-mediated language learning. Focus group interviews and questionnaires revealed two principal factors influencing belief systems: affect and the perceived utility of computers in second language education. A theoretical framework defining belief systems and the demographic, contextual and experiential constructs directing belief systems and consequent actions using computer technology is outlined. The majority of participants reported having used computer technology in their practices, and demonstrated positive attitudes towards computers in ESL instruction. The regular use of computers was found to positively influence both teachers' attitudes and perceptions that computer technology is an effective teaching tool. Teachers with 10 to 20 years of teaching experience most positively perceived computers as valuable resources in ESL instruction. Gender, age, education level, college affiliation and computer training did not significantly influence teacher belief systems towards computer-mediated language learning.
Heat shock transcription factors and the hsp70 induction response in neural and non-neural tissues of the hyperthermic rat during postnatal development

Heat shock transcription factor 1 (HSF1) levels increase in brain regions during postnatal rat development, but decrease in kidney and heart, HSF1 protein levels in brain and kidney correlate with levels of HSF DNA-binding activity and the magnitude of hsp70 protein induction after thermal stress in both neonatal and adult rats. There appears to be more HSF1 protein in adult brain than is needed for induction of hsp70 after thermal stress, suggesting that HSF1 may have other roles in addition to its role as a stress-inducible activator of heat shock genes. HSF2 protein levels decline during postnatal rat development in brain regions, kidney and heart. Gel mobility shift analysis showed that HSF2 is not in a DNA-binding form in the neonatal rat, suggesting that HSF2 may not be involved in the constitutive expression of heat shock proteins in early postnatal development. There is no apparent correlation between levels of HSF2 protein and basal levels of hsp90, hsp70, hsc70 and hsp60.
Cognitive and motor development in children with vertically transmitted HIV infection

We examined a broad range of neuropsychological functioning in three distinct cohorts of infants, preschool, and school-age children with vertically transmitted HIV infection. Our results are the first to assess development in a group of Canadian children with vertically transmitted HIV infection. Children were administered a battery of age-appropriate developmental or neuropsychological tests assessing, where possible, intelligence, receptive language, expressive language, visual and verbal memory, visual-motor speed and coordination, fine motor skill, and academic achievement. At the time of assessment, the children were on different antiretroviral therapies consistent with clinical practice at the time of testing. Results revealed that infants with HIV-infection are significantly delayed in mental, motor and adaptive functioning. The preschool cohort showed results that indicated that mean overall IQ for the group was reflective of average performance. A relative weakness was documented on a measure of receptive vocabulary. School-age children with vertically transmitted HIV infection showed many areas of cognitive function within the normal range. However, subtle motor impairments were documented and our results are the first report of fine motor and motor strength deficits in school-age children with HIV. The results should not be used to generalize a developmental trajectory for children with vertically transmitted HIV infection because the three studies are cross-sectional in design.
An inquiry into the integration of indigenous knowledges and skills in the Kenyan secondary science curriculum

A major argument in the promotion of 'science' in the schools is the need to link 'scientific' thinking to everyday problem-solving. It is assumed that such a linkage will help improve existing life conditions. However, in rural Kenya and in many other parts of rural Africa, secondary science education has not had a significant effect on existing life conditions. This study attempts to explain this failure in terms of two underlying deficiencies: first, secondary science omits and de-emphasizes everyday knowledge and skills; second, it promotes sets of ideas and myths about science that are incompatible with its 'experienced' practices. Some academic theorizing and empirical research work to address these issues has focused on the context-boundedness of knowledge, a field of study that is known as situated cognition theory. A closely linked focus for academic theorizing is the notion of alternative sources of knowledge production and validation outside the existing 'schooled'1 frameworks, which are mainly Eurocentric. An alternative framework view holds that all cultures have their ways of understanding and explaining natural phenomena. It follows that promoting just one way of understanding and explaining natural phenomena is limiting the diversity of human experiences and is potentially alienating and disempowering to students and teachers who may choose to explain and understand natural phenomena differently, or at least to consider alternatives. The study aims to contribute to the body of literature on situated cognition by identifying modes of everyday knowing and suggesting how to establish a dialectic between these modes of knowing and 'schooled' science. To identify modes of knowing, I investigated health and healing in a rural part of Kenya, Kirumi, between April and September 1997. Most participants were women because women are, in their role as caretakers, heavily involved in matters of health and healing and, tberefore, are more likely than men to generate a wide variety of data. Their role as caretakers also bestows on them the great responsibility of communicating everyday knowledge to current and future generations. 1The term 'schooled' refers to knowledge and skills that are designated for instruction in schools.
Regional differences in cat esophageal circular smooth muscle, a white noise analysis

By using a Gaussian white noise identification technique, regional differences are demonstrated by differences in electrical response characteristics. Gaussian white noise measurements and analysis techniques were used to obtain input impedance functions of myocytes from feline esophageal body cells (EBC) isolated from 2 and 4 cm above the lower esophageal sphincter. A whole cell patch-clamp configuration was used to inject white noise current and record a voltage response. The magnitude of the input impedance of the cell was calculated from the first order kernel. Fourier transforms of the kernel indicate a difference in input resistance. The time constants obtained indicated that EBC-4 was quicker to respond since the higher frequency values correspond to a faster response characteristic of the cell. There are regional differences in the passive cable properties of smooth muscle cells from the smooth muscle esophagus which likely contribute to the contraction profile and sequential nature of peristalsis.
Eating disorders in adolescent females with type 1 diabetes mellitus, a controlled three-site study

Body dissatisfaction and dieting have become increasingly common in young women in Western countries, and are often associated with a cycle of binge-eating, further dietary restriction, and purging behaviours. In females with type 1 diabetes mellitus, this cycle may be triggered or amplified due to several aspects of diabetes and its management. Eating disorders have been found to be relatively common in adolescent females with type 1 diabetes and are associated with impaired metabolic control and an increased risk of microvascular complications. However, controversy persists as to whether eating disorders occur more frequently in females with diabetes than in their non-diabetic peers. A 3-site, 2-stage cross-sectional study was conducted to compare the frequency of eating disorders in 356 adolescent females with type 1 diabetes (mean age 15 ± 2 years) to 1098 age-matched non-diabetic controls. Eating disorders were assessed using self-report screening measures followed by a standardized diagnostic interview for those scoring above predetermined cut-off levels. Metabolic control in diabetes subjects was assessed by hemoglobin A1c. Eating disorders that met DSM-IV criteria were more prevalent in subjects with diabetes (10.1 percent) than in non-diabetic controls (4.5 percent, P < 0.001). Sub-threshold eating disorders were also more common in those with diabetes (13.8 percent) than in controls (7.6 percent, P < 0.001). Body mass index was higher in diabetes subjects (22.6 ± 3.8 kg/m 2) than controls (20.6 ± 3.3 kg/m2, P < 0.0001), and diabetes subjects with an eating disorder were older at diabetes onset than those without. At screening, insulin dosage manipulation to promote weight loss was reported by 11 percent of the subjects with diabetes, and by 42 percent of subjects diagnosed with a DSM-IV disorder. Mean hemoglobin A1c was higher in diabetes subjects with a DSM-IV eating disorder (9.4 ± 1.8 percent) than in those without (8.6 ± 1.6 percent, P = 0.004). DSM-IV and sub-threshold eating disorders were almost twice as common in adolescent females with type 1 diabetes as in their non-diabetic peers, and were associated with insulin manipulation for weight loss and impaired metabolic control.
Effect of antenna configurations on soft handoff and coverage performance of wireless CDMA systems

An analytical model of base station antenna configurations for wireless CDMA systems is proposed. By both numerical evaluation and simulations we investigate the effect of antenna pattern, antenna downtilting, azimuth configuration, and cell layout on soft handoff and forward link coverage performance. The investigation shows that antenna patterns with different characteristics should be properly selected based on different system configurations. For three-sectorized system, pattern with 65° beamwidth gives best performance. And non-interleaving configuration, or antenna orientation of within 10°, is rational. For six-sectorized system, antenna with 33° beamwidth at 15° orientation is preferred. Its corresponding total handoff percentage is comparable to the selections for three-sectorized case. Antenna downtilting can substantially affect the handoff and coverage probability distributions but their percentage variations are not significant. This model provide a basic building block for future development of the software tool for planning and optimizing the forward link of cellular CDMA network.
Genetic interactions between the ABA insensitive mutant, abi1-1, and the ABA supersensitive mutant, era1-4, in Arabidopsis thaliana

The mutant, 'abi1-1' (ABA i_nsensitive), is insensitive to exogenous and endogenous ABA (abscisic acid) and thus is defective for a number of physiological responses. The mutant, 'era1-4 ' (e_nhanced r_esponse to A_BA), was isolated in a suppressor screen of 'abi1-1'. The 'era1-4' mutant is able to suppress many of the defective ABA responses of ' abi1-1' examined to varying degrees, from not at all to complete suppression, depending on the character. Further study of the 'abi1-1' and the 'era1-4' mutants revealed developmental defects previously unreported. When the two mutations are combined, there are more severe developmental effects specifically in the stomate and floral organ number. This implies ABI1 and ERA1 may have broader roles in Arabidopsis development than previously known.
Neuropsychological deficits as predictors of treatment outcome in patients with temporomandibular disorders

The primary objective of this study was to assess the utility of neuropsychological tests as predictors of treatment outcome for patients with temporomandibular disorders (TMD). Psychosocial and clinical variables were also included as confounders and secondary outcome measures. In the overall, the nrTMD did worse in both the neuropsychological and psychosocial assessment with higher memory deficits, sleep disturbances, levels of depression and fatigue, and lower energy levels; but both groups could not be distinguished from each other based on clinical variables usually assessed in the TMD examination. The California Verbal Learning Test - correct responses (CVLTCR), the California Verbal Learning Test - clusters (CVLTCL), and the Brown-Peterson Consonant Trigram Auditory Memory Task (CCC) were capable of differentiating responding (rTMD) versus non-responding TMD (nrTMD) patients prior to treatment even after controlling for eleven psychosocial and clinical variables used in the analysis and other four included in the design. Among the best predictors, the CCC in a backward stepwise logistic regression was chosen as the best predictor of all neuropsychological tests. Three psychosocial variables were also found to be good predictors: (a) sleep, (b) depression, (c) fatigue, and (d) income. Among clinical variables, only pain on chewing pre-treatment was found to be predictors. Our secondary objective was to assess if the neuropsychological and psychosocial profile between irritable bowel syndrome (IBS) and nrTMD patients were much more similar than those between the IBS and the rTMD group. On average, both nrTMD and IBS patients did worse in the neuropsychological and psychosocial tests than the rTMD with higher memory deficits, higher levels of depression, sleep disorders and fatigue, and lower energy levels. Taken in combination, the data suggested that neuropsychological differences exist between the nrTMD versus rTMD patients. In addition, it was also demonstrated that two unrelated chronic pain conditions (i.e. IBS and nrTMD) may share similar neuropsychological characteristics. Therefore, solid and reproducible evidence was provided with the use of neuropsychological tests in favor of the biopsychosocial model of chronic pain. This study also supported the multidisciplinary management approach for patients with temporomandibular disorders.
Policy, philosophy or propaganda?, ecosystem management in sequoia national forest

The emergence of "ecosystem management" within resource management discourse reflects growing support for management directed at sustaining ecosystems. This thesis reviews ecosystem management literature and identifies four dominant themes of ecosystem management. This framework is employed to examine United States Forest Service implementation of ecosystem management at the local level. A case study examining giant sequoia management in Sequoia National Forest, California, is presented. The Sequoia National Forest case study suggests that the application of ecosystem management is affected by poor relations between managers and stakeholders, inadequate policies and ineffective policy implementation, and a lack of ecological research on which to base management decisions. Six recommendations are presented: (1) improving communication and establishing trust; (2) encouraging confidence in and commitment to the process; (3) acknowledging biases; (4) investing in research and science; (5) reconciling policy and funding constraints with long-term planning; and (6) exploring the relationship between values and science.