The ground state naive pluripotency is established in the epiblast of the blastocyst and can be captured by culturing mouse embryonic stem cells (mESCs) with MEK and GSK3 inhibitors (2i). The transcription network that maintains pluripotency has been extensively studied with the indispensable core factors being Oct4, Sox2 and Nanog, together with other ancillary factors reinforcing the network. However, how this network is dissolved at the onset of differentiation is still not fully understood. To identify genes required for differentiation in an unbiased fashion, I conducted a genome-wide CRISPR-Cas9-mediated screen in Rex1GFPd2 mESCs. This cell line expresses GFP specifically in the naive state and rapidly down-regulate upon differentiation. I differentiated mutagenised mESCs for two days and sorted mutants that kept higher GFP expression. gRNA representation was subsequently analysed by sequencing. I identified 563 and 8 genes whose mutants showed delayed and accelerated differentiation, respectively, at a false discovery rate (FDR) cutoff of 10%. The majority of the previously known genes were identified in my screen, suggesting faithful representation of genes regulating differentiation. Detailed screening result analysis revealed a comprehensive picture of pathways involved in the dissolution of naive pluripotency. Amongst the genes identified are 19 mTORC1 regulators and components of the mTORC2 complex. Deficiency in the TSC and GATOR complexes resulted in mTORC1 upregulation in consistent with previous studies. However, they showed opposite phenotype during ESC differentiation: TSC complex knockout cells showed delayed differentiation, whereas GATOR1 deficiency accelerated differentiation I found that the pattern of GSK3b phosphorylation is highly correlated with differentiation phenotype. I conclude that mTORC1 is involved in pluripotency maintenance and differentiation through cross-talk with the Wnt signalling pathway. My screen has demonstrated the power of CRISPR-Cas9-mediated screen and provided further insights in biological pathways involved in regulating differentiation. It would be interesting to explore the remaining unstudied genes for better understanding of the mechanisms underlying mESC differentiation.

Recreational screen time activities (e.g., computer use, television viewing, and videogame engagement) have become increasingly embedded in modern day culture, posing both physical and psychological health consequences (Babic et al., 2017; Goldfield et al., 2013). Despite the established link between recreational screen time and adolescent depressive symptomatology, little is known about mechanisms that may explain or influence this relationship. The overarching objective of the present dissertation, which includes two separate studies, was to examine cognitive, behavioural, affective, and interpersonal factors associated with the relationship between adolescents’ total daily recreational screen time activities and depressive symptomatology over time. The dissertation includes archival data from the Research on Eating and Adolescent Lifestyle (REAL) Study, which examined a large sample of students from the National Capital Region of Canada. Both Study 1 and Study 2 examined a subsample of these students. Given that exposure to screen time occupies up to 10 hours of Canadian children and adolescents’ waking hours (Active Healthy Kids Canada, 2013; Leatherdale & Ahmed, 2011; Leatherdale & Harvey, 2015), the independent variable examined in the model was total daily recreational screen time activities. Because trajectories of depressive symptomatology typically increase during adolescence (Duchesne & Ratelle, 2014), the dependent variable examined in the model was depressive symptomatology. The time points spanned over 7 years. The purpose of Study 1 was to test a prospective longitudinal path analysis model. The model examined the relationship between total daily recreational screen time at baseline (T0) and depressive symptomatology at Time 4 (T4), with body image and disordered eating behaviours at Time 2 (T2) as potential mediating variables. The final sample included 304 English-speaking students (194 females, Mage = 13.40 years, SD = 1.10). Total daily recreational screen time at T0 was significantly predictive of depressive symptomatology at T4. Appearance (dis)satisfaction at T2 mediated the relationship between total daily recreational screen time at T0 and depressive symptomatology at T4. Total daily recreational screen time at T0 was significantly predictive of emotional eating and decreased body image satisfaction at T2. Restrained eating and appearance satisfaction were negatively associated with depressive symptomatology at T4. Results were independent of age and depressive symptomatology at T0. The purpose of Study 2 was to test a longitudinal moderation model including total daily recreational screen time at T0 and depressive symptomatology at T4, with attachment style, coping style, and perceived social support at T0 as potential moderating variables. The final sample included 170 English-speaking students (106 females; Mage = 13.01, SD = 0.96). Contrary to expectation, attachment style, coping style, and perceived social support did not moderate the relationship between total daily recreational screen time at T0 and depressive symptomatology at T4. However, insecure attachment was identified as a risk factor for depressive symptomatology among males. A trend emerged in that avoidance-oriented coping appeared to be a risk factor for depressive symptomatology among females and a protective factor for males. There was also a three-way interaction between total daily recreational screen time, gender, and perceived social support. That is, when perceived social support was high, higher levels of total daily recreational screen time at T0 was associated with higher levels of depressive symptomatology at T4 for both males and females, but the relationship was significant for males only. Findings from the present dissertation offer important theoretical, methodological, and clinical implications.

The main purpose of this study was to determine the effect of contour height on the passage ratio of pulp through screen apertures, and determine which operating variable has the greatest affect on screen performance. In addition, a freeness model was to be developed, in hopes of helping to predict the freeness drop between feed and accepts. The study was conducted at The University of British Columbia (UBC) using a laboratory scale pressure screen. Slot velocity, feed consistency and contour height were the changing variables. Samples were collected from which passage ratio, freeness, fibre length and coarseness were determined. From the studies conducted it was found that slot velocity had the greatest influence on the screen operation. As the slot velocity increased a greater force was applied to the fibre to help push it through the screen aperture. However, this increase in slot velocity decreases the fractionation ability (separation of fibres into different lengths) of the screen. The second most important variable was the contour height. The main function of the contour height is to disrupt the flow of thick stock at the wall of the screen and allow for unhindered movement of fibre to the screen wall. The greater the contour height is, the greater the passage ratio (pulp fibre passing through screen). However, there is a decrease in fractionation. The third most important factor was the feed consistency. At low feed consistencies there is less crowding in the screen. Less crowding leads to more loosely-formed flocs, which are easier for the contour height and the rotor to dissipate and thus leads to unhindered movement. Thicker feed stock has a negative effect on passage A Freeness model was developed that showed that freeness had a power law relationship to passage ratio. The passage ratio was raised to a constant B, which is a function of the contour height and the feed consistency. / Applied Science, Faculty of / Chemical and Biological Engineering, Department of / Graduate

In 1543, after more than a century of exploration and expansion, the first Europeans, the Portuguese, landed on the Isle of Tanegashima fl ~lib, off the southern island of Kyushu, Japan. Their arrival has been described in Japanese as kamikaze 1$ 00,, 'by the winds of the gods', or by accident. Indeed the Portuguese did not intend to visit Japan; their landing on Japanese shores was caused by severe weather conditions. The focus of this dissertation is the so-called Nanban byobu l�J~ MOO. Southern Barbarian folding screen paintings, depicting the arrival of Portuguese merchants and missionaries on Japanese shores. The paintings are classified as kinsei shokifuuzokuga ili:t!t1'.JJ~OO.{~@ (Early Modern Genre Painting) depicting scenes from contemporary life in and around the city. They were designed and produced by Japanese artists for Japanese patrons and audiences, they were not items made for export. Typically the screens were displayed in pairs, each screen consisting of two, six or eight panels and are divided into groups of 'arrival scene' paintings; the first group shows the departure of the Portuguese 'Black Ship' from a foreign port on the left screen and the right the arrival of the ship to Japan, the next group show the arrival of the Portuguese 'Black Ship' to Japanese shores on the left screen and on the right screen is a procession of Portuguese merchants and missionaries through the streets of a Japanese port town. Around ninety screens survive and can be found in collections worldwide. The aim of this study is to 're-contextualise' these paintings in the Japanese interior space and the practice of Japanese painting workshops. It intends to challenge the frequent use of European sources to decipher and make meaning of the iconography of Nanban byobu by reconsidering their place in the development of Japanese painting in the early modern period.

Acute myeloid leukemia (AML) is a highly fatal blood cancer that is characterized by disruption of healthy differentiation of stem cells into functional blood cells in the bone marrow. Most patients with AML consequently die from infections due to the lack of immune cells. For decades, the standard method of remission induction for AML has been chemotherapy using an antineoplastic drug known as AraC. However, even after successful remission induction, aggressive, refractory relapse occurs in the majority of patients within 3 years with dismal survival rates. Here, we sought to develop a genome-wide screening approach to determine the causative genes in AML relapse. In the developed procedure, protein-coding genes of the human genome are screened using a leading-edge technology known as CRISPR (clustered regularly interspaced short palindromic repeats) activation screening. This involves usage of a pooled guide RNA library that upregulates a unique gene for each individual AML cell. By treating these cells with AraC in a mouse xenograft model, the bone marrow will gradually be enriched with cells that carry a guide RNA for a relapse-conducive gene. By harvesting and sequencing all enriched guide RNAs at relapse, the causative genes in AML relapse can be determined. All parameters of the in vivo CRISPR-activation screen have been optimized, and the workflow from preparation to the end of screening has been detailed. Follow-up studies that will validate the results of the screen have also been described. The long-term goal of this developed screen is to elucidate the mechanisms of AML relapse and find ways to clinically target these pathways in conjunction with standard the AraC-based chemotherapy. / Thesis / Master of Science (MSc)

how does a structure signal change? in the absence of conformational alteration, of opening or closing, a dynamic must develop as a temporal function of the participant's experience. in a place where change is sought after, the mask of the skin is lifted. renewal is found. / Master of Architecture

When I walk over Hatteras Island, I experience three things: the sand beneath my feet, the Ocean toward the East, and the Sound toward the West. Each has different qualities yet all three can be experienced simultaneously. It is my intention not to obstruct this connection, but rather to accentuate it. I will design a dwelling that will tie the sand, the Ocean, and the Sound together. It will be a reflection of the qualities of each of these natural elements. The dwelling will take on the characteristics of a screen, with many different levels of permeability, while providing the necessary amount of livable space. / Master of Architecture

A Simple way to improve solar cell efficiency is to enhance the absorption of light and reduce the shading losses. One of the main objectives for the photovoltaic roadmap is the reduction of metalized area on the front side of solar cell by fin lines. Industrial solar cell production uses screen-printing of metal pastes with a limit in line width of 70-80 μm. This paper will show a combination of the technique of laser grooved buried contact (LGBC) and Screen-printing is able to improve in fine lines and higher aspect ratio. Laser grooving is a technique to bury the contact into the surface of silicon wafer. Metallization is normally done with electroless or electrolytic plating method, which a high cost. To decrease the relative cost, more complex manufacturing process was needed, therefore in this project the standard process of buried contact solar cells has been optimized in order to gain a laser grooved buried contact solar cell concept with less processing steps. The laser scribing process is set at the first step on raw mono-crystalline silicon wafer. And then the texturing etch; phosphorus diffusion and SiNx passivation process was needed once. While simultaneously optimizing the laser scribing process did to get better results on screen-printing process with fewer difficulties to fill the laser groove. This project has been done to make the whole production of buried contact solar cell with fewer steps and could present a cost effective opportunity to solar cell industries. / <p>In collaboration with Institute for Photovoltaics <strong><em>IPV</em></strong>, University of Stuttgart.</p>

No description available.

This study investigates the adaptability of plastic paints to photographic silk screen materials and methods. The problem was to experiment with and further develop another technique for the artist, the silk screening of photographic images directly onto the painting surface with acrylic polymer paint.