The mutant prevention concentration (MPC) is defined as the lowest antimicrobial concentration required to inhibit the growth of the least susceptible bacterial cell based on an inoculum of ≥109 colony forming units (CFUs). The current protocol for MPC testing is technically demanding and time-consuming which limits its implementation into clinical microbiology laboratories. In an attempt to simplify the current MPC protocol we developed a modified MPC method, the microbroth dilution method, which requires two fewer days to complete than the current or traditional method. MPC values were consistent for all organisms and strains tested using both the traditional MPC method and the modified microbroth dilution MPC method.<p> Tigecycline is the first of a new class of compound glycylcyclines- with potent in vitro activity against Gram-positive organisms including penicillin-resistant and multi-drug resistant <i>Streptococcus pneumoniae</i> (SP) and methicillin-resistant <i>Staphylococcus aureus</i> (MRSA). We measured minimum inhibitory concentration (MIC) and MPC values for tigecycline against 47 clinical isolates of SP and found that the MPC90 values were >500 fold higher than the MIC90 values. To determine if MPC testing of tigecycline against SP is impacted by blood in the medium, we developed a new medium able to sustain the growth of SP without the need for blood; solidified Todd-Hewitt broth (sTHB). The MPC90 values of tigecycline against SP on sTHB were only 2 fold higher than the MIC90 values. When blood was added to the sTHB, the MPC90 values again became much greater than the MIC90 values (> 256 fold higher). MPC results for <i>Staphylococcus spp.</i> against tigecycline were not impacted by blood in the medium.<p> Benzalkonium chloride (BAK) is a cationic surface-acting agent that acts on bacterial cells by disrupting the intermolecular interaction of the lipid bilayer. To determine if the <i>fluoroquinolones gatifloxacin</i> (Gfx) and moxifloxacin (Mfx) are more active (lower MIC values) in the presence of BAK, we conducted MIC, MPC, and time-kill assays. MIC testing showed that in the presence of 3.125 to 50 µg/ml of BAK, the MIC of Gfx and Mfx decreased by 8- to 5000-fold against clinical isolates of methicillin-susceptible <i>Staphylococcus aureus</i> (MSSA), MRSA, Coagulase-negative <i>Staphylococci</i>(CNS), SP, <i>Escherichia coli</i> (EC), and <i>Pseudomonas aeruginosa</i> (PA). MPC testing showed that the presence of 7 to 10 µg/ml of BAK, the MPC of Gfx and Mfx decreased by 32- to 1000-fold against clinical isolates of MRSA. Conventional time-kill studies (using a bacterial load of 105 CFUs) showed that the killing activity of Gfx against clinical MRSA isolates was enhanced in the presence of BAK with a log10-reduction (percent kill) of 1.6 (76.08%) for Gfx alone at 180 minutes compared to a log10-redecution (percent kill) of 5.4 (100%) for Gfx plus BAK at 180 minutes.<p> Alexidine (Alx) is a bisbiguanide that has been used as an effective disinfectant in the dental industry and is potentially being developed for use as an antimicrobial agent for ocular infections. We conducted susceptibility testing of Alx using MIC testing, MPC testing, and time-kill assays against Gram-positive and Gram-negative pathogens. MIC testing showed that Alx is more active against Gram-positive pathogens than Gram-negative pathogens and showed better activity than the fluoroquinolones Gfx, Mfx, and levofloxacin (Lfx) against MRSA. The MPC values measured for MRSA and MSSA against Alx were non-reproducible using the traditional MPC method. Using the microbroth dilution MPC method, MPC90 values were found to be 32 fold higher than the MIC90 values. If the experimentally determined MPC values are true MPC values, initial MPC testing indicates that Alx may have a high likelihood for selecting for resistance, however, if the MPC values are not accurate it may be necessary to modify the MPC protocol in order to complete MPC testing of Alx against MRSA and MSSA. Conventional time-kill studies (using a bacterial load of 105 CFUs) measured bactericidal activity (> 3 log10-reduction) against MRSA, MSSA, SP, and PA.

In modern times the increasing complexity of transistors and their constant decreasingsize require more effective techniques to display and interpret the processes that are inside of devices. In this work, we are modeling a two‐dimensional n‐MOSFET with a long channeland uniformly doped substrate. We assume that this device is a large geometry device so that short‐channel and narrow‐width effects can be neglected. As a result of the thesis, a demonstration program was built. In this executable file, the user can choose parameters of the MOSFET‐model: drain and gate voltage, and different geometrical parameters of the device (junction depth and effective channel length). In the advanced regime of the program, the user can also specify the model re‐calculation parameter, doping concentration in n+ and bulk regions. The program shows the channel between the source and drain region with surface diagrams of carrier density and potential energy as an output. It is possible to save all calculated results to a file and process it in any other program, for example, plot graphics in Matlab or Matematica. The model can be used in lectures that are related to semiconductor physics in order to explain the basic working mechanisms of MOSFETs as well as for further detailed analysis of the processes in MOSFETs. It is possible to use our modeling techniques to rebuild the model in another computer language, or even to build other models of transistors, performing similar calculations and approximations. It is possible to download the executable file of the model here: http://studentdevelop.com/projects/MOSFET_model.zip

The television industry in Lithuania is analyzed in this thesis with a focus on the impact of commercialization on the public service broadcaster. The purpose of the research paper is to describe the impact of the changing market on the public service broadcaster of Lithuania using as theoretical framework the approach of the political economy of the media and communication and quantitative methods. One part of the thesis is the theoretical research, which is done by analyzing and systematically presenting books and articles that relate to the thesis’s topic. In the second part of the work, the theoretical framework is applied to the Lithuanian television market. In addition, an empirical study is conducted in order to apply the theoretical discussion and answer the main research question. The main results of the study suggest that the public service broadcaster of Lithuania managed to maintain its programmes’ diversity. However, the amount of entertainment, imported production and advertising has increased. Therefore, a certain concern about growing commercialization is reasonable. These changes correspond to the tendencies in the European television industry. However, Lithuanian viewers seem to prefer the more heavily commercialized programmes since the leader of the market is a commercial television station, whose market share is almost twice bigger than LTV’s. Thus, LTV is facing a dilemma between preserving quality and diversity and commercializing its programmes in order to increase its audience share (dilemma between quality and audience share).

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In this paper, we examine the effects of market competition on corporate performance. In the first stage, we use Herfindahl-Hirschman Index to measure the degree of competition and markets are divided into three categories, namely competition, moderate competition and oligopoly. Fama-French is used to examine whether there is abnormal return existing in competition market. Then we use the index constructed by Chen, Kao, Tsao and Wu (2007) to decide the performance of internal governance and use it with competition degree to conduct the regression. This paper finds the following results, 1. the moderate competition market is reducing; 2. the portfolio of firms in competition markets outperforms that in oligopoly; 3. market competition has positive effect on ROA, ROE, EPS and Tobin¡¦s Q; 4. market competition and corporate governance are complementary.

The topic of this thesis is solar pump Nd-doped double-clad fiber laser, the main characteristic of this research is we use nature and low pollution source pump unique laser gain medium. By using Neodymium-doped double-clad fiber in form of waveguide structure to replace Neodymium-doped glass, Neodymium-doped yttrium aluminum garnet crystals that have large cross-section area of the volume in the past¡F natural sunlight is used as pumped source in instead of diode laser, pulsed Xenon lamp, Krypton arc lamp¡Ketc. In order to reduce the use of electric power source and decrease the pollution . By using Solar concentration system, we focus average sunlight power density (800W/m2) to very high power density. In application, If lasers are needed in remote locations where sunlight is abundant and other forms of energy sources are scarce, this kind of solar energy usage is not a bad idea.

This dissertation evaluates the changes in food retailing patterns in the face of openmarket trends in a medium sized city (Citlalicalli) in central Mexico. This evaluation is carried out using the model of retail trade-concentration. The following questions are addressed: whether trade-concentration had occurred in the field-site; if yes, what were the causes; and, what were the effects of retail concentration on preexisting food retailers. The fieldwork for this study was conducted over a 14 month period (May 2005 and June 2006). Empirical data were collected using three surveys, over 25 interviews, and several hours of participant observations. Along with these primary data, secondary data from official records were also collected. The survey data were analyzed using nonparametric tests. The findings from the study revealed that trade-concentration is proceeding in Citlalicalli and the recent spread of large stores in the region has been encouraged by free-trade policies adopted by Mexico since the mid-1980s. Trade-concentration in the Altepetl metropolitan area has also been aided by the positive behavior that consumers show towards large retail chains. Contrary to popular belief, the impact of retail concentration on preexisting small retailers in Citlalicalli has been minimal. Partly traditions and partly the nearness of a particular store explain the continued patronization of small stores by consumers. The product category and income of consumers also influence their purchase decisions. This research shows that competition in food retailing in developing countries is between same size and same type retailers. Small retailers are not always in direct competition with modern retailers as they serve different sections of the society. Retail development is a part of urban development and, therefore, has direct implications for the quality of life in cities. In emerging economies, cities like Citlalicalli have vibrant town centers which provide convenient access to offices, shops, and entertainment areas for its citizens. This study concludes that appropriate policy measures can ensure the coexistence of large and small retailers in developing countries and, thereby, the continued vitality of city centers.

Carbon foams exhibit numerous unique properties which are attractive for light weight applications such as aircraft and spacecraft as a tailorable material. Carbon foams, when exposed to air, oxidize at temperatures as low as 500-600 degrees Celsius. The research objectives of this study are to assess the degree of oxidation of carbon foam by experimental and computational methods and evaluate the degradation in stiffness of the bulk foam as a function of oxygen concentration profile, time and temperature. In parallel to simulation, oxidation tests are conducted to observe changes in morphology and to calculate the apparent activation energy. Degradation patterns in the carbon foam microstructure are categorized through optical microscopy (OM) images post oxidation. The influence of microstructure and temperature on the oxygen concentration profile is investigated in parametric models with varying porosity. The degradation in bulk foam stiffness is found to be strongly dependent on the temperature and non-uniform oxygen concentration profile. The overall results enhance the design of experiments for high temperature and oxidative environments, illustrating the relationship between foam microstructure and oxygen concentration in porous media.