Punching shear capacity of flat slab-column junctions (a study by 3-D non-linear finite element analysis)

This thesis presents a study of punching shear capacity of flat slab-column junctions. A three dimensional non-linear finite element program based on 20 node isoparametric solid element was used for the investigation. The non-linear 3-D elastic isotropic model proposed by Motsovos was used to describe the behaviour of concrete before cracking or crushing. After cracking, a yield criteria for 2-D model similar to Kupfer-Hilsdorf was used and concrete was assumed to be anisotropic. No softening in compression is assumed. Smeared crack approach with simple tension stiffening and shear retention equations were employed to mimic the post-cracking behaviour of concrete. Reinforcing bars were represented by one dimensional element embedded in the solid elements and for both tension and compression, linear elastic-plastic behaviour is assumed. A comparison was first made between the predictions of slab behaviour using Kotsovos' model (In-house program) and plasticity based model used in the commercial package ABAQUS. From this it was concluded that Kotsovos' concrete model is a good model for the three dimensional analysis of the punching shear problem but the ABAQUS model was unsuitable. In order to achieve an accurate and economical solution for the non-linear analysis, a parametric study was carried out to choose a suitable analytical model. After having chosen the "best" concrete model, over 175 slabs from different sources were analysed using a constant set parameters. The analysis includes various types connections (interior, edge and corner) with and without shear reinforcement, subjected to shear force alone or to a combination of shear force and unbalanced moment. These slabs cover most of the factors affecting punching shear strength, such as slab thickness, flexural reinforcement ratios, concrete strength, and column size. This study also includes the effect of in-plane restraint on punching shear strength of slabs

Epigenetic regulation of lentiviral and retroviral vectors in murine embryonic stem (ES) cells and genetic modification of ES cells with lentiviral vectors for application in regenerative medicine

Embryonic stem cells are characterized by their self-renewal capability and pluripotency. They represent an unlimited cell source for regenerative medicine. In order to genetically modify ES cells for gene therapy, self-inactivating lentiviral vectors (SIN-LVs) have been proposed as versatile tools for the gene transfer in vitro, ex vivo or in vivo leading to stable transgene expression (Matrai et al, 2010; Pfeifer et al, 2002). Although retroviral vectors (RVs) were also used for the genetic modifications of ES cells, a major limitation in using RVs is the epigenetic silencing (Jahner et al, 1982). However, the performance of SIN-RVs as well as SIN-LVs has been reported in HSCs (Schambach et al, 2006a) but not in ES cells. Therefore, in the first part of this work the focus lied on the comparison between SIN-LV and SIN-RV transduction of ES cells. The data obtained showed a similar transgene expression level of both SIN-LVs and SIN-RVs transduced ES cells under undifferentiation conditions. Under differentiation conditions transgene silencing in SIN-LVs as well as SIN-RVs transduced ES cells was observed that mainly was due to CpG methylation. For both vectors the contribution of CpG methylation to transgene silencing was of the same extent. For a more accurate analysis of SIN-LV- and SIN-RV-mediated transgene expression, transduced ES cell clones with either high or low expression level were picked for further analysis. In case of SIN-RV ES cell clones, both clones (low and high expressing) showed strong transgene silencing under differentiation conditions due to CpG methylation. In contrast, only the low expressing SIN-LV ES cell clone showed high CpG methylation level under differentiation conditions. Importantly, the high expressing LV ES cell clone revealed a lower CpG methylation level and transgene expression was still observed under differentiation conditions. Moreover, using subzonal injection for the generation of transgenic mice, injection of SIN-LVs in preimplantation embryos resulted in around 50 % transgenic mice of born pups whereas SIN-RVs subzonal injections led to less than 1 %. This data indicated the successful and efficient usage of SIN-LV transduction of murine embryos whereas SIN-RVs showed very low efficient transduction. Taken together, SIN-LVs seem to be the proper vehicle for gene transfer either in ES cells or in embryos for the generation of transgenic mice. Using pluripotent stem cell derived cells for regenerative medicine carries the potential risk of tumor formation due to the contamination with residual undifferentiated cells (Blum & Benvenisty, 2008; Nussbaum et al, 2007; Wakitani et al, 2003). Therefore, the specific elimination of pluripotent stem cells was investigated in the second part of this work. Pluripotent stem cells including ES and iPS cells were transduced with LVs carrying thymidine kinase (TK) from Herpes simplex virus under control of promoters of pluripotency genes. TK expressing cells are in turn sensitive to ganciclovir (GCV) as TK converts GCV into a toxic metabolite leading to cell death. Treatment of TK transduced pluripotent cells in not further selected (mixed) cell populations with GCV led indeed to a high elimination of undifferentiated cells. Although picked single LV-transduced ES cell clones showed a higher killing efficiency upon GCV treatment complete elimination of undifferentiated cells was not observed. However, raising TK expression by using the stronger EOS promoters in mixed ES cell populations did also not result in a significant reduction of undifferentiated cells. In order to obtain complete transduced cell populations, a pre-selection strategy with hygromycin resistance gene was thus applied. These STPH (LV-EOS-S4-TK-PGK-Hygromycin)-transduced ES cell populations carrying only low copy number of LVs demonstrated a complete elimination of undifferentiated cells after Hygromycin pre-selection upon GCV administration in vitro. More importantly, no teratoma was observed when pre-selected cells were injected into mice that were treated with GCV. These in vivo data confirmed the in vitro findings and suggested that STPH-transduced ES cells with pre-selection seemed to be completely eliminated upon GCV treatment if they did not undergo differentiation. This gives rise to possible promising applications in future clinical approaches

Student Perceptions Of The First Course In Accounting: Majors Versus Non-Majors

This paper contributes to the continuing debate regarding the curriculum for the first undergraduate course in accounting by examining student perceptions from studying such a course. Participants are divided into two cohorts - Accounting & Finance Majors (AFM) and Other Business Majors (OBM). Results reported in this paper indicate that teaching the introductory accounting course from a users’ perspective is likely to engender a more favorable impression from students than teaching from a preparers’ perspective. Findings indicate that the AFM cohort holds significantly more positive attitudes to the first course in accounting than does its OBM counterpart. Furthermore, AFM student perceptions do not change between the beginning and the end of the course. In contrast, the OBM students respond less favorably at the end of the course than at the beginning. Findings underscore the difficulty of developing a first course in accounting that is interesting, useful and challenging to accounting and non-accounting majors

Design and fabrication of bead-based microfluidic device

Ph.DDOCTOR OF PHILOSOPH

Spillover Effects from Greek Sovereign Bonds : Evidence from Asia Pacific Banking Portfolios

The European Crisis that originated from Greece then its spillover to Portugal, Spain, Cyrus, Italy and Ireland, and finally transforming into the European crisis we know today. It was claimed that the fire broke loose with the spark from U.S. subprime crisis that resulted in a credit crunch, and the aforementioned European countries that were heavily indebted, where their debts are 100% more than their respective GDPs failed to secure credit lifelines to service their debts. The domino effect is history, and in fact the crisis had just crossed its 5 years milestone while we are researching on its spillover effect. The trigger point of research interest is that the crisis does not seem to go away anytime soon. Greece, who was claimed to be the epicenter of the crisis, is under the limelight again to be the first developed nation to default on its financial obligation, and the first country to be kicked out of European Union (EU). In July 2015, the development in Greece had spread like wildfire across the globe and indirectly forcing policy makers to appear before the media to comment on its implication to their respective economy. While “Grexit” remains the sole interest of EU, the concerns on credit default effect are beyond boundaries. The debates revolve around key stakeholders from Greece, German, France, IMF and ECB, while the rest of the EU countries’ involvement are minimal to casting their votes on the bailout decisions. The development also caught the attention from Asia pacific countries, which on their own account also experienced multiple crises from the 1997 Asia financial crisis, followed by the U.S. Subprime Crisis, and potentially the current European Crisis. People are nervous and policy makers are making their rounds to address their concerns, hopefully genuinely. While earlier research papers emphasized mainly on European region found that the spillover from Greece is significant on its peer countries, but recent papers discovered that effect of mitigation have managed to isolate and contain Greece’s spillover effect from neighboring countries. However, the spillover effect from Greece to Asia pacific countries are less than a handful and the estimation window emphasize mainly on pre-crisis and immediately in 2010, while the findings from the earlier papers indicated that there is no evidence of spillover from Greece on Asia pacific countries. We reckon that the 5 years milestone had ample of room for development and suspect that the spillover effect was not stagnant in 2010 alone. Having these in mind, our paper focuses on the current estimation window to reflect the revival of Greece crisis from January 2014 to August 2015 using daily data of the bank portfolios from six sample countries in Asia Pacific : Australia, China, Japan, Singapore, South Korea, and Taiwan. We employed GARCH regression model to mitigate heteroscedasticity to generate the event-­‐induced volatility for the respective banking portfolios. While our regression estimates found to be consistent with earlier research that our sample countries are insulated from Greek crisis, our literature review indicated that the sample countries are indeed vulnerable to external shocks, at least from specific countries with high correlation on its debts and bilateral trades

Cellular gene expression profiles of human macrophages exposed to Chlamydia pneumoniae and treated with low density lipoprotein

Master'sMASTER OF SCIENC

Dimensional Stability of Lightweight Foamed Concrete Containing Eggshell Powder and Calcium Stearate

In order to reduce eggshell (ES) waste and reduce utilization of pure cement, various researches were conducted to study effects of eggshell powder (ESP) on properties of concrete when it partially replaces ordinary Portland cement (OPC). Dimensional stability is one of the properties that related to cracking issue and soundness of concrete, and it is generally guided by movement of moisture. This study was conducted to study the sorptivity, initial surface absorption, and dimensional stability of lightweight foamed concrete (LFC) that containing eggshell powder and calcium stearate (CS), where, replacement level (RL) of eggshell powder ranged from 0% to 10% at interval of 2.5%, and additional of 1% calcium stearate as cement mass applied for the mixture containing 0% and 5% eggshell powder. The result shows that eggshell powder improves sorptivity, initial surface absorption, and dimensional stability of lightweight foamed concrete and the optimal replacement level is 5%. The result also shows that calcium stearate significantly improves these properties, regardless that incorporation of eggshell powder in the mixture containing calcium stearate might slightly deteriorate these properties. Besides, based on the results, improved sorptivity and initial surface absorption result in increased magnitude of shrinkage as the specimen has lower ability to absorb water for expansion throughout the testing period

Synthesis and mesomorphic properties of new heterocyclic liquidcrystals with Central Ester–Chalcone linkages

A series of new calamitic liquid crystals, 4-[3-(pyridin-4-yl)prop-2-enoyl]phenyl 4-alkyloxybenzoates, comprising a pyridyl core,ester–chalcone central linkage and terminal alkyloxy chain were synthesized and characterized. This series consists of four membersthat differ by the length of the alkyloxy chain (CnH2n+1O , where n = 10, 12, 14, 16). The structures of the title compounds wereelucidated using spectroscopic and spectrometric techniques, such as FT-IR, NMR (1H and13C) and EI-MS. The mesomorphicproperties were studied using differential scanning calorimetry and optical polarizing microscopy. The decyloxy-containing com-pound was found to be non-mesogenic, whilst the compounds containing n-dodecyloxy to n-hexadecyloxy chains exhibited anenantiotropic smectic A phase with a fan-shaped texture. From the structure–property relationship study, it was proposed that thenumber of carbons in the alkyloxy chain must be at least 12 (n ≥ 12) to generate the smectic phase in the corresponding substitutedArCOOArCOCH CHC5H4N compounds