VictorJuiz/thesis huggingface dataset:
In-line colour monitoring and molecular changes during corn extrusion cooking

A study originally directed at simply adapting an in-line colour monitoring system of synthetic polymer extrusion to extrusion cooking, of necessity, resulted in the development of a new "in-line" calibration procedure that greatly improved the quality of the results. This significant outcome was one of many from a broadly based colour monitoring study of extrusion cooking. All five objectives of the work were accomplished. A precise and accurate in-line colour monitoring system based upon a charge-coupled-device (CCD) visible spectrophotometer was implemented. Accurate and precise colour changes during extrusion of corn flour were obtained in real-time by the new in-line calibration system. A semi-empirical model for correlating CIELAB in-line and off-line colour data was performed and assessed. A suitable method to SEC fractionate corn meal and extrudates was developed. And finally, using methanol-extraction UV-vis spectrophotometry, the progress of the Maillard reaction as a function of the extrusion conditions was detected off-line.
Empowering youth: perceptions and use of computers in school-based community development

This thesis explored the use, experience, and perceptions of computer technology by senior elementary youth as a tool to support them in a school-based community development (CD) project. Nineteen predominantly female youth, attending a Southwestern Ontario, inner city school participated in a 12-week CD project. Youth used computers to communicate using a computer-mediated-communication (CMC) system, construct a project web site, conduct an online survey to gather peers' opinions about the community, search for resources, and prepare documents. A qualitative instrumental case study method was used. Data collection strategies included participant observation, interviews, focus groups, two online and two paper-based surveys, and quantitative and qualitative analysis of on-line discourse. At the start of the CD process, youth felt that they could "make a difference" in their community and that group action and influential adults could support their voice. They also perceived that they had some decision-making power in their school, but little power in the broader community. This was related to their perception of being low in social hierarchy and mistrusted by adults. Youth perceived that the computer was an empowering tool. They felt that using computers helped reduce their anxiety, increased their control in communicating with adults, raised their social status, increased their participation with the community, and improved access to resources. Web site construction and online surveying were particularly valued. Although important community contacts were made using CMC, few notes were written and read by youth. This was related to computer access issues (insufficient time for computers, lack of computer availability, and technical problems) and a lack of engagement in CMC. Youth perceived that using CMC felt like work and lacked authenticity. Some also had limited computer skills or little interest in computers. In addition, adults' messages were misinterpreted by youth and youth lost some credibility online as a result of their use of fictitious cyber names. The study also revealed factors in the school and in youth's relationships with adults that enabled and constrained the CD process. Overall, results strongly indicate that youth perceived that computers supported their empowerment. Recommendations for practitioners and future research are provided.

Keywords: Youth, Curricula
Community development
Education, Data processing
Computer literacy
Teaching
Association between early childhood caries and child maltreatment outcomes in preschool children

Objectives. To collect data on ECC prevalence and severity using the dfmt/s index in children with a history of maltreatment and determine whether untreated decay rates in the primary dentition differ between abused and non-abused children. Methods. A retrospective prevalence analysis was conducted using data from the existing dental and social records of Children's Aid Society of Toronto. Results. The study included a total of 66 records. Untreated decay was observed in 58% of the abused children. 56.6% of neglected children. The mean 'dt' value was 5.40 (SE 0.68) and 3.12 (SE 0.52) for the whole sample. Children who have been in care more than once or for a period of one year were less likely to have experienced caries. Conclusion. Abused/neglected young children have higher levels of tooth decay than the general population; however, this study did not find differences in decay prevalence between types of maltreatment.
High pressure soot formation in non-smoking methane-air laminar diffusion flames from 1.5 MPa to 6.0 MPa

Measurements of soot concentration, flame temperature and flame geometry have been recorded for non-smoking methane-air laminar diffusion flames at pressures from P = 1.5 MPa to P = 6.0 MPa. Soot concentration and temperature profiles were obtained using the spectral soot emission diagnostic method and the Abel inversion deconvolution technique. Visual inspection and measurement of the flame revealed a slight increase in height and decrease in cross-section with increasing pressure. Soot volume fraction increased with pressure according to fv max prop; P1.4 for 1.5 le; P le; 5.0 MPa. The maximum carbon conversion to soot was related to pressure following the relationship eta s, max prop; P0.55 for 1.5 le; P le; 5.0 MPa. The maximum value of carbon converted to soot was etas, max = 10.1% at P = 5.0 MPa. The maximum soot concentration was always found at a height approximately half way between the burner and the flame tip. The temperature was lower in high soot loading regions of the flame. For the same height in the flame, temperature decreased with increasing pressure.

Keywords: Combustion
Soot
Chosen ciphertext security in identity based encryption

One of most important goals of cryptography is to allow two parties to establish a "secure line" of communication without assuming the existence of a shared secret. This goal is typically achieved by using Public Key Cryptography. In recent years, a new variation of public key cryptography, called Identity Based Encryption (IBE) has emerged. In this thesis we discuss the definitions of chosen ciphertext security for IBE, present a new definition which is reasonable yet strictly stronger than previous ones, and construct an efficient IBE system which is secure in our strong definition. We also review the elegant public key encryption system of Kurosawa and Desmedt and present a new proof of security.
Breast cancer screening: the effects of format presentation of probabilistic information on comprehension and intentions

For effective communication of risk/benefit information, it is important to ensure that the recipient understands probabilistic information. Comprehension may be influenced by whether the format in which probabilistic information is presented (i.e., numeric versus verbal) matches people's format preferences. An experimental design was used to explore this problem in the context of mammography screening. A convenience sample of 180 women aged 25–45 years with no history of breast cancer and mammography received pre-assembled randomized packages, containing a breast health information pamphlet and four questionnaires, in either verbal or numeric format. The questionnaires assessed women's comprehension and self-reported intention to use screening mammography. “Match” (n = 95) and “mismatch” (n = 85) subgroups emerged based on whether or not the received format was congruent with women's preferences. There was no significant match/mismatch subgroup difference in mean overall comprehension scores. However, the mean comprehension score was lower in those who received numeric but preferred verbal than in those who received and preferred verbal format (16 vs. 44, F = 19.50; p < 0.001). Among the women who received the numeric format, overall comprehension was related to educational level; the mean comprehension score was lower for those with ≤grade 13 than those with higher education (17 vs. 42, t = 4.64; p = 0.001). There was no significant match/mismatch subgroup difference in intention to use screening mammography. Women who intended to seek screening reported higher: overall baseline knowledge of breast cancer/screening (OR = 1.26; CI = 1.13, 1.40); perceived risk of encountering breast cancer (OR = 3.35; CI = 1.19, 9.46); and perceived usefulness of information (OR = 7.56; CI = 2.40, 23.89). This study is unique in targeting younger women and revealing limited breast cancer knowledge in this group. The results indicate that comprehension of probabilistic information may be associated with format preference, particularly when information is communicated quantitatively. The results also imply that systematic investigation is needed to characterize the relationships among format preferences, various types of numeracy problems, and strategies for communicating information that foster satisfactory levels of comprehension. Finally, the study design could guide future exploratory investigations regarding risk perception, comprehension, and decision formation in other screening programs.
Exploration of an online network with women entrepreneurs: a case study

The present in situ qualitative case study describes the events and processes that led a group of 21 women entrepreneurs to form an online networking community. For one year, all participants, who had minimal computer-mediated communication experience, were encouraged to use the university's asynchronous shared virtual space software as a potential alternative to face-to-face networking. I originally planned to observe and to describe the online interactions that would capture these business owners' activities. Because of the participants' responses and the issues that arose, I became an active participant. Barriers hindering the success of this education and entrepreneurial collaboration involved six participant reluctance themes related to: (1) computer skills, (2) priorities, (3) relevance, (4) trust, (5) privacy, and (6) professional image. In contemplating a final online event called a speaker's series, participants expressed a risk to their professional image. Their disclosure prompted a more satisfying design activity and additionally corroborated the other reluctance themes. Encouragement through experimentation with elements of learning organization practice, a learning process called re-cognition, the co-production of user-defined events, the safeguarding of user image, and through multiple roles undertaken by me, the researcher, addressed six types of reluctance and led to the participants forming an online networking community. The significance of this study is multi-faceted: Models for developing an online networking community, technology adoption, and individual change for a digital setting are provided; the case study demonstrates that applied cross-sector research on learning and entrepreneurism can take place in situ; leveraging the strengths of those who are initially technologically reluctant is possible; addressing issues of professional image holds promise for expanding the uses of shared virtual spaces; innovative activities can be symbolic and measurable attributes of learning and problem-solving; and education can take the lead in evolving a knowledge- and technology-based world.

Keywords: Entrepreneurship, Computer network resources
Women-owned business enterprises
Strategic alliances (Business)
Business networks
Telecommunication
Computer literacy
Clustering of centromeric domains in cerebellar Purkinje and granule neurons is chromosome-specific and cell-type specific

Centromeric domains of chromosomes reproducibly form clusters in interphase nuclei of Purkinje neurons. Using chromosome-specific, para-centromeric probes, the present work identified centromeric regions of individual chromosomes and their relative positions with respect to others. Significant clustering was observed between the centromeres of subsets of chromosomes in both Purkinje and granule neurons. In Purkinje neurons, some chromosome centromeres always clustered while others never did. Some of the chromosomes that clustered in Purkinje neurons, never clustered in granule neurons. Clustering therefore, is deemed to be cell-type specific. We speculate that the specific centromere clustering pattern in different neurons may identify structural adaptations of these cells for neuron-specific gene expression.
Molecular mechanism of phagocytosis: A role for CD44

CD44, a transmembrane adhesion molecule involved in binding and metabolism of hyaluronan, has additional functions in inflammatory and immune responses, contributing to the ingestion and clearance of particles and apoptotic cells. Our goal was to determine the specific role of CD44 in phagocytosis and whether it functions as a primary or accessory phagocytic receptor. Using hyaluronan-coated beads and erythrocytes coated with anti-CD44 antibodies as the phagocytic prey, we determined that CD44 mediates efficient phagocytosis in primary murine peritoneal macrophages and in the murine macrophage cell line RAW 264.7. In RAW cells, the phagocytic index for anti-CD44-coated erythrocytes was 25 +/- 3 (mean +/- SEM) compared to
Studies of electrokinetic transport phenomena in microfluidic devices

This thesis studies the electrokinetic transport phenomena in microfluidic devices. The scope of this thesis work is best broken down into two parts. The first part concentrates on the theoretical and experimental study of Joule heating effects on the transports of heat, electricity, momentum and mass species in capillary-based electrophoretic separations. It is found that Joule heating effects cause temperature gradients in both cross-stream and stream-wise directions. As a result, the electric field and thus the electrical body become non-uniform in flow equations so that pressure gradients are induced passively to satisfy the mass continuity. This disturbance to the otherwise plug-like electroosmotic flow field increases the sample dispersion and hence reduces the separation efficiency. The second part of this thesis work concerns the electrophoretic motion and the electrokinetic manipulation (for example, focusing, dispensing and separation) of particles and cells in microfluidic chips. Theoretical predictions of the particle electrophoretic mobility that are available in the literature are experimentally validated in both cylindrical and rectangular microchannels by visualizing the single particle motion. We also examine intensively the accelerated particle electrophoretic motion and separation in converging-diverging microchannels along with the focused electrophoretic motion of particles and cells in cross-microchannels. In addition, an electrokinetic method is proposed to dispense efficiently single particles in a double-cross microchannel. The totally electrokinetic manipulation of particles is believed to facilitate developing integrated lab-on-a-chip devices for studies of single cells.
A mechanistic study of mitochondria mediated agonist-induced cytosolic calcium decrease

In this thesis I examined how a neurohumoral signal, operating on calcium mobilizing G-protein coupled receptors (GPCRs) can mediate both an increase and a decrease in cytosolic Ca2+ levels. The model system used was an astrocytoma cell line that had been transfected with a P2Y2 receptor known to mobilize Ca2+ via an IP3 dependent pathway. Following blockade of the sarco/endoplasmic reticulum calcium ATPase (SERCA) using thapsigargin (Tg), a monophasic agonist-induced cytosolic calcium decease (AICD) was observed upon UTP application. I further investigated possible roles and modulators of AICD. I started by investigating which Ca2+ stores were sequestering cytosolic Ca2+ during AICD. I showed that mitochondria demonstrated noticeable Ca2+ uptake during AICD. Thus, additional work presented in this thesis focused on the mechanism by which mitochondria mediated AICD upon UTP addition in Tg pre-treated cells. A pharmacological approach was adopted to allow manipulation of the physiological status of the mitochondria so that the roles and interaction of various components in the mitochondria in the AICD phenomenon could be fully investigated. I first showed that inhibition of the ETC complexes and the MCU was able to prevent AICD. I then demonstrated that the cyclosporin A sensitive permeability transition pore (PTP) can mediate either Ca2+ uptake or release depending on cellular and mitochondrial conditions. Moreover, I showed that putative PTP mediated AICD was enhanced by nitric oxide decreases in a manner that may be related to ETC complex I activity. I provided evidence using MTT assay showing that conditions associated with enhanced AICD were also associated with preserved mitochondrial functions. Overall, my thesis has demonstrated a newly discovered strategy used by the mitochondria in cellular calcium regulation. While the MCU functioned to take up Ca2+ into the mitochondria with high local Ca 2+ concentrations after Tg treatment, PTP mediated Ca2+ uptake upon UTP stimulation seemed to mediate a more global phenomenon resulting in AICD. These properties of PTP allow it to integrate with other mitochondrial systems such as the ETC and NOS so that a coordinated system of regulation can precisely respond to the status of the cell.
Modular architecture design of reconfigurable machine tools for agile manufacturing

In industry, agile manufacturing is gaining more and more attention. To support agile manufacturing, reconfigurable machine tool has been introduced, which can be reconfigured to satisfy different machining requirements. In the early stage of reconfigurable machine tool design, machine tool architecture design is an important issue. Due to the lack of information in the early design stage, it is difficult to generate and select feasible machine tool architecture solutions. In light of this challenge, the purpose of this thesis is to develop a systematic modular architecture design methodology for reconfigurable machine tools. For illustration and validation, the methodology has been applied to an illustrative design problem. The results demonstrate the applicability and validity of the proposed methodology. The design methodology proposed in this thesis consists of three stages: module identification, module selection, and module layout synthesis. Module identification is to collect module components (building blocks) for the reconfigurable machine tool to be designed. In particular, the module identification stage involves two steps: decomposition of the existing machine tools into module components and establishment of a module component library as the selection space for the module selection stage. Module selection is to evaluate the selected module components and select an optimal set of module components for the reconfigurable machine tool design. The module selection stage involves two steps: determination of the functional requirements required to manufacture a target part family and selection of module components from the module component library. Module layout synthesis is to generate reconfigurable machine tool architecture solutions (which are represented by module layouts) and select the desired architecture solutions according to a set of criteria. The module layout synthesis stage involves two steps: module layout generation and module layout selection. In module layout generation, the methods for generalized layout enumeration, generalized layout enumeration are presented. In module layout selection, reconfigurability, structural stiffness, and error sensitivity are treated as three module evaluation criteria and selection is performed based on the indices of those criteria.
Design of an injection-molding system for manufacture of microcellular foams

An innovative microcellular foam injection-molding system is systematically designed, constructed, and experimentally verified in this research. The basic approach is to form and maintain a homogeneous, single-phased polymer/gas solution, to induce a microcellular cell-nucleation rate, and to mold the nucleated polymer/gas mixture into a desired shape while preventing deterioration of cell density and achieving a desired void fraction. Because cell density strongly depends on the concentration of gas dissolved in the polymer, the formation of a homogeneous polymer/gas solution with a high gas concentration is the primary requirement. To maintain a constant gas-to-polymer weight ratio despite the stop-and-flow molding behaviors, a positive-displacement gear pump is located between the extrusion barrel and the accumulator. The polymer/gas solution is accumulated under a pressure higher than the solubility pressure to prevent the formation of a gas phase in the solution. To nucleate myriad cells, a rapid pressure drop is utilized. The cell-nucleating behaviors of polymer/gas solution are separately investigated using an extrusion-foaming system with nine deliberately designed nucleating dies with various pressure-drop rates and die pressures. These studies indicate that the pressure-drop rate is the most critical for the PS-CO2 system, whereas the CO 2 and nucleating-agent contents contribute to cell nucleation. Based on these results, effective strategies to achieve a desired cell density during injection molding are established. The cell-nucleating behaviours in injection molding are investigated in several stages of calibration experiments for each section of the system. Experience demonstrated that the microcellular-nucleating strategies in injection molding should be different from those in extrusion. Finally, manufacture of microcellular foams in injection molding is successfully demonstrated through critical experiments. The cell-deteriorating phenomena are also identified and studied at various melt temperatures. To determine solubility accurately, a preliminary investigation is conducted to model and fit the pressure-volume-temperature (PVT) data of PS/CO 2 solutions using the Simha-Somcynsky (S-S) equations of state (EOS). The PVT data of PS/CO2 mixtures obtained from the literature are used as a case example to determine the characteristic parameters of S-S EOS.
Examining group differences in omission rates in a mathematics assessment

Omission rates in large-scale assessment data can threaten the reliability and validity of the reported student scores. A number of studies have examined examinees' omission rates on high-stakes assessments, but few have examined omission rates on low-stakes assessments. In addition, many studies have focused on multiple-choice items, but few have included constructed-response items. This study extends previous research to examine the omission patterns on a low-stakes large-scale assessment that includes both multiple-choice and constructed-response items. Omission rates in relation to item format and student demographics are compared while controlling for ability level. The results showed that omission rates were related to the item formats and subgroup membership of examinees.
Role of nitric oxide in the treatment of type 2 diabetes with American ginseng (Panax quinquefolius L.)

To investigate the role of nitric oxide (NO) in the treatment of diabetes with American ginseng extract (AG), a double-blind, placebo-controlled study was conducted in 24 type 2 diabetic subjects. They were randomized to take either AG 2.25g/day or placebo for 8 weeks, then crossover with at least 4 weeks washout. Blood pressure was determined and fasting blood was taken to assess NO, glycemic parameters and lipid peroxidation. During AG treatment, NO increased significantly compared to placebo (P = 0.031). The change was negatively correlated to HbA1c (R = −0.42, P = 0.043), which decreased (P = 0.026) following AG. Fasting blood glucose, lipid peroxidation and blood pressure were improved with AG (P < 0.05 respectively). </p> It is concluded that in type 2 diabetes, AG reduced cardiovascular risk factors such as hypertension and improved glycemic control which was associated with NO enhancement.