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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
501

Investigation of Hsf1 Interacting Partners via a Genome-wide Yeast Two-hybrid Screen

Mendez, Jamie Elizabeth 01 January 2013 (has links)
Heat shock factor 1 (HSF1) is the master transcriptional regulator of the heat shock response (HSR), an evolutionarily conserved cellular stress response. HSF1 promotes the expression of a variety of molecular chaperones that aid in restoring protein homeostasis upon exposure to proteoxic stress. However, all of the proteins responsible for regulating the HSR together with HSF1 are unknown. A genome-wide yeast two hybrid screen was performed to identify new S. cerevisiae Hsf1 protein interacting partners. Two GAL4 DNA binding domain-Hsf1 fusion proteins (baits) were constructed with mutations in the Hsf1 C-terminal activation domain to dampen Hsf1 mediated auto-activation of the reporter gene. Each haploid bait strain was mated with a haploid prey strain containing one of ~6,000 S. cerevisiae open reading frames fused to the GAL4 activation domain (prey). Interaction between the bait and prey reconstituted the GAL4 protein enabling it to bind to a GAL4 DNA binding site and activate the HIS3 reporter gene. The identified proteins from 4 screens were pooled generating 240 putative Hsf1 interacting partners. This list was narrowed to 38 candidates by selecting the 15 strongest interactions identified based on colony size and 33 candidates conserved in C. elegans. Hsf1 interactions with the 14 candidates in which protein expression was confirmed were then re-tested by a manual yeast two-hybrid assay. Hsf1 interactions with Sti1, Rim2 and Prp46 were repeatable in this manual assay. A study of the impact of knockdown of each of their C. elegans homolog on the HSR was performed using RNAi in an hsp70-promoter::GFP reporter strain of C. elegans. Preliminary results suggest that knockdown of Sti1 may impact the HSR in the worm. Further study of Sti1 and other potential Hsf1 interacting partners identified in this screen is warranted.
502

Shock Instability in Gases Characterized by Inelastic Collisions

Sirmas, Nick 20 February 2013 (has links)
The current study addresses the stability of shock waves propagating through dissipative media, analogous to both granular media and molecular gases undergoing endothermic reactions. In order to investigate the stability, a simple molecular dynamics model was developed to observe shock waves and their structures with the inclusion of energy dissipation. For this, an Event Driven Molecular Dynamics model was implemented in a 2D environment, where a molecule is represented by a disk. The simulations addressed the formation of a shock wave in a gas by the sudden acceleration of a piston. Inelastic collisions were assumed to occur only if an impact velocity threshold is surpassed, representing the activation energy of the dissipative reactions. Parametric studies were conducted for this molecular model, by varying the strength of the shock wave, the activation threshold and the degree of inelasticity in the collisions. The resulting simulations showed that a shock structure does indeed become unstable with the presence of dissipative collisions. This instability manifests itself in the form of distinctive high density non-uniformities behind the shock wave, which take the form of convective rolls. The spacing and size of this ``finger-like" unstable pattern was shown to be dependent on the degree of inelasticity, the activation energy, and the strength of the driving piston. The mechanism responsible for the instability was addressed by studying the time evolution of the material undergoing the shock wave compression and further relaxation. It is found that the gas develops the instability on the same time scales as the clustering instability in homogeneous gases, first observed by Goldhirsch and Zanetti in granular gases. This confirmed that the clustering instability is the dominant mechanism.
503

Cultural adjustment : an exploratory case study of the Japanese Exchange Teaching programme and its implication for social work practice

Callender, Shauna January 2003 (has links)
Culture shock and reverse culture shock are profoundly personal experiences affecting individuals in a multitude of diverse ways. They happen inside each person who encounters unfamiliar events and unexpected situations. For people who work abroad (sojourners), cultural adjustment is a significant time in their lives. Following the examination of cultural adjustment, a review of literature is explored, highlighting sojourners' acculturation and coping strategies. A case study of the JET (Japanese Exchange Teaching) Programme is presented through an analysis of public documents and interviews with JET staff and former sojourners. Findings report that JET sojourners experience adjustment difficulties with reverse culture shock and that there exists an unavailability of resources providing support. Limitations of the study are highlighted; areas of weakness were found in the lack of literature addressing the needs and experiences of sojourners, particularly JETs. Recommendations and suggestions for future research in the field of social work are made.
504

Shock induced chemical reactions in energetic structural materials

Reding, Derek James 03 February 2009 (has links)
Energetic structural materials (ESMs) constitute a new class of materials that provide dual functions of strength and energetic characteristics. ESMs are typically composed of micron-scale or nano-scale intermetallic mixtures or mixtures of metals and metal oxides, polymer binders, and structural reinforcements. Voids are included to produce a composite with favorable chemical reaction characteristics. In this thesis, a continuum approach is used to simulate gas-gun or explosive loading experiments where a strong shock is induced in the ESM by an impacting plate. Algorithms are developed to obtain equations of state of mixtures. It is usually assumed that the shock loading increases the energy of the ESM and causes the ESM to reach the transition state. It is also assumed that the activation energy needed to reach the transition state is a function of the temperature of the mixture. In this thesis, it is proposed that the activation energy is a function of temperature and the stress state of the mixture. The incorporation of such an activation energy is selected in this thesis. Then, a multi-scale chemical reaction model for a heterogeneous mixture is introduced. This model incorporates reaction initiation, propagation, and extent of completed reaction in spatially heterogeneous distributions of reactants. A new model is proposed for the pore collapse of mixtures. This model is formulated by modifying the Carol, Holt, and Nesterenko spherically symmetric model to include mixtures and compressibility effects. Uncertainties in the model result from assumptions in formulating the models for continuum relationships and chemical reactions in mixtures that are distributed heterogeneously in space and in numerical integration of the resulting equations. It is important to quantify these uncertainties. In this thesis, such an uncertainty quantification is investigated by systematically identifying the physical processes that occur during shock compression of ESMs which are then used to construct a hierarchical framework for uncertainty quantification.
505

Set-up and evaluation of laser-driven miniflyer system

Miller, Christopher W. 08 April 2009 (has links)
A laser-driven miniflyer system is built in design similar to those at the Los Alamos National Laboratory and Eglin Air Force Base. It is composed of three parts: laser drive source, impact experiment assembly, and diagnostics. The laser drive source is a Nd:YAG laser operating at 1064nm at a maximum energy of 3 J. The impact experiment assembly consists of a BK7 substrate on to which is deposited an ablation layer consisting of carbon, alumina, and aluminum. Mounted on the ablation layer is a metal foil (flyer). The carbon in the ablation layer absorbs the laser energy to form a rapidly expanding plasma. The alumina and aluminum layers provide thermal insulation and also contain the plasma. The set-up is expected to provide flyer velocities in the range of 100 to 1000 m/s. Diagnostics consist of a Photonic Doppler Velocimetry (PDV) system that uses Doppler-shifted coherent laser light to measure the instantaneous velocity of a moving surface, as well as velocity dispersions caused by mechanical or material heterogeneities. This thesis will provide a description of the set-up of the laser-driven miniflyer system, as well as an evaluation of the flyer velocity, measured using the PDV system, as a function of laser energy. The flyer velocity trends will be used in order to characterize and calibrate the system. A manual providing system operation instructions will also be included to serve future users of this miniflyer system
506

Drivers of Australian merger waves: industry shocks, mis-valuation and capital liquidity

Porwal, Anmol January 2008 (has links)
The purpose of this thesis is to test the extended industry shock hypothesis, which accounts for a macro-economic capital liquidity element, in determining the drivers of merger waves. Various theories have been extended by the literature and these are broadly classified under the neo-classical theory of merger waves and the behavioural theory of merger waves. Behavioural theories have explained merger waves by taking into account the psychology of stock markets and the occurrence of merger waves during a stock market boom. The industry shock hypothesis (a neo-classical theory) however, argues that merger waves are due to the clustering of industry shocks that affect an industry’s operating environment. Along with this shock, the mis-valuation caused by a stock market boom increases asset values, thereby lowering transaction costs and hence increasing capital liquidity in the economy. This capital liquidity factor causes merger waves to cluster even if industry shocks do not. The findings in this study show that industry level merger waves exist in Australia and they occur when there is sufficient capital liquidity in the economy. The industry shock variables are found to be insignificant; however they do improve the explanatory power of the explanatory variables used in predicting the start of a merger wave. The mis-valuation variables used in this study: market-to-book ratio, 3-year return and standard deviation of the 3-year return, are insignificant and do not have any explanatory powers in predicting the start of a merger wave. Merger and acquisition announcements made to acquire Australian firms listed on the Australian Stock Exchange (ASX), are collected and analysed for the period from 1996 to 2007. The methodology used in this study is adopted from Harford (2005), which uses legit models to predict the start of merger waves. The explanatory variables are also adopted from Harford’s (2005) study and include proxies for mis-valuation, industry shock and capital liquidity. Overall, the results obtained for the Australian merger and acquisition data are inconclusive as to whether industry shocks because industry merger waves as Harford (2005) documented for the US merger and acquisition data. However, industry level merger waves do exist, as there is clustering in time of firm-level mergers within industries. Moreover, sufficient capital liquidity must be present to accommodate the necessary transactions.
507

Pathogenesis and immunotherapy of streptococcal septicemia and shock /

Ihendyane, Nahla, January 1900 (has links)
Diss. (sammanfattning) Stockholm : Karol. inst., 2003. / Härtill 4 uppsatser.
508

The effectiveness of the Culture Shock Adaptation Inventory, II in assessing the degree of cultural adaptation of foreign graduate students

Ribbe, David Paul. January 1987 (has links)
Thesis (M.A.)--Trinity Evangelical Divinity School, 1987. / Abstract. Includes bibliographical references (leaves 115-127).
509

Endothelin receptor antagonism and hypertonic solutions in experimental endotoxin shock /

Somell, Anna, January 2007 (has links)
Diss. (sammanfattning) Stockholm : Karolinska institutet, 2007. / Härtill 4 uppsatser.
510

Streptococcus pyogenes infections and toxic shock syndrome : molecular epidemiology and immunotherapy /

Darenberg, Jessica, January 2006 (has links)
Diss. (sammanfattning) Stockholm : Karolinska institutet, 2006. / Härtill 4 uppsatser.

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