ABSTRACT: Commercial swab transport systems are used for collection and transporting of fecal and other microbiological samples. This system must maintain viability and contribute to survival of microorganisms during transport to the laboratory. Four swab transport systems have been compared, eSwab, Σ- Transwab and fecalSwab, all three with flocked swabs, and Copan Venturi Transystem with rayon swabs. The study followed the recommendations from the Clinical Laboratory Standard Institute; document M40-A for recovery of Samonella, Shigella, Yersinia and Neisseria gonorrhoeae after storage for 0, 6, 24, 48 and 72 h at room- (22-25°C) and refrigerated (2-8ºC) temperature. A fecal sample has also been inoculated with Salmonella or Shigella to simulate a fecal sample positive for Salmonella or Shigella. Recovery of all strains was higher with eSwab, Σ- Transwab and fecalswab than with Copan Venturi Transystem stored at both temperatures. A heavy growth was observed with all transport systems after storage for 24, 48 and 72 h at room temperature, except for Neisseria gonorrhoeae, and Shigella. The number of CFU for all strains was constant up to 72 h at refrigerated temperature with Copan Venturi Transystem. In the experiment with fecal sample recovery of Salmonella and Shigella was best with fecalSwab at both storage temperatures. ESwab, Σ- Transwab and fecalSwab are equivalent and can be used as an alternative to Copan Venturi Transystem with better survival of enteric pathogens and Neisseria gonorrhoeae. Fecal samples should be refrigerated in order to avoid heavy overgrowth of fecal flora.

Biological sample analysis is a costly and time-consuming process. It involves highly trained technicians operating large and expensive instruments in a temperature and dust controlled environment. In the world of rising healthcare cost, the drive towards a more cost-effective solution calls for a point-of-care device that performs accurate analyses of human blood samples. To achieve this goal, today's bulky laboratory instruments need to be scaled down and integrated on a single microchip of only a few square centimeters or millimeters in size. Dielectrophoresis (DEP), a phenomenon where small particles such as human blood cells are manipulated by non-uniform electric fields, stands to feature prominently in the point-of-care device. An original device that enhances DEP effect through novel geometry of the electrodes is presented. When activated with two inverting sinusoidal waveforms, the novel-shaped electrodes generate horizontal bands of increasing electric fields on the surface of the microchip. With these bands of electric fields, particles can be manipulated to form a straight horizontal line at a predictable location. Experimental results showing the collection, separation, and transportation of mammalian cells are presented. A strategy for simultaneous processing of two or more types of particles is also demonstrated. With capabilities for an accurate position control and an increased throughput by parallel processing, the novel microchip device delivers substantial improvements over the existing DEP designs. The research presented here explores the effects of novel electrode geometries in cell manipulations and contributes to the overall progress of an automated blood analysis system.

The work presented in this thesis aims to further the understanding and implementation of the Baculovirus Expression Vector System (BEVS) for varied uses such as protein production and viral vector production. To this end, three projects have been presented, two of which deal with methods to quantify baculovirus titres and the last deals with tracking baculovirus transcripts in infected insect cells. The first project examined assumption-free analysis as a method for data analysis of Real Time PCR data in order to enable direct comparison of baculovirus titres between samples, without the need for a traditional standard curve. It concluded that assumption-free analysis was well suited for this purpose and fold differences of baculovirus titres of different samples obtained using this method corresponded to real differences in sample titres. The second project aimed to develop a cheap and reliable method for sample preparation for Real Time PCR which would remove the need for the use of commercially available extraction kits. Samples were subjected to various combinations of Triton X-100 at different concentrations and different numbers of freeze/thaw cycles in order to determine the combination which would provide the best baculovirus genome exposure. One of these combinations was found to be at least as good as commercially available kits in reliably extracting baculovirus DNA and providing baculovirus titres that are at least as accurate. The third project was a preliminary study examining the effects of multiplicity of infection on the levels of baculovirus Gp-64 transcript in insect cell culture. The study concludes that at high multiplicities of infection, there seems to be no increase in baculovirus transcripts when the multiplicity of infection is further increased. This study served to allow for familiarization with tracking transcript levels, and the principles and techniques demonstrated here will form the basis for an exhaustive future study on the same subject.

Numerous studies have documented the application of crash severity models to explore the relationship between crash severity and its contributing factors. These studies have shown that a large amount of work was conducted on this topic and usually focused on different types of models. However, only a limited amount of research has compared the performance of different crash severity models. Additionally, three major issues related to the modeling process for crash severity analysis have not been sufficiently explored: sample size, model misspecification and underreporting in crash data. Therefore, in this research, three commonly used traffic crash severity models: multinomial logit model (MNL), ordered probit model (OP) and mixed logit model (ML) were studied in terms of the effects of sample size, model misspecification and underreporting in crash data, via a Monte-Carlo approach using simulated and observed crash data. The results of sample size effects on the three models are consistent with prior expectations in that small sample sizes significantly affect the development of crash severity models, no matter which model type is used. Furthermore, among the three models, the ML model was found to require the largest sample size, while the OP model required the lowest sample size. The sample size requirement for the MNL model is intermediate to the other two models. In addition, when the sample size is sufficient, the results of model misspecification analysis lead to the following suggestions: in order to decrease the bias and variability of estimated parameters, logit models should be selected over probit models. Meanwhile, it was suggested to select more general and flexible model such as those allowing randomness in the parameters, i.e., the ML model. Another important finding was that the analysis of the underreported data for the three models showed that none of the three models was immune to this underreporting issue. In order to minimize the bias and reduce the variability of the model, fatal crashes should be set as the baseline severity for the MNL and ML models while, for the OP models, the rank for the crash severity should be set from fatal to property-damage-only (PDO) in a descending order. Furthermore, when the full or partial information about the unreported rates for each severity level is known, treating crash data as outcome-based samples in model estimation, via the Weighted Exogenous Sample Maximum Likelihood Estimator (WESMLE), dramatically improve the estimation for all three models compared to the result produced from the Maximum Likelihood estimator (MLE).

In this thesis, a switched-current sample-and-hold circuit is proposed. We use feedback circuit to decrease the input impedance and to reduce the transmission error in SI cell. Furthermore, the entire memory cell is designed in a coupled differential replicate form to eliminate the clock feedthrough (CFT) error. The sample-and-hold circuit is simulated using the parameters of TSMC 0.35£gm CMOS process. The simulation results show that the spurious-free dynamic range (SFDR) is 55 dB, the sampling rate is 40MHz, the power consumption is 0.38 mW, and the power supply is 1.5V. Furthermore, the circuit is verified by cadence-hspice simulation.

Thesis (Ph.D.)--University of Alabama at Birmingham, 2007. / Title from PDF title page (viewed on Feb. 19, 2010). Includes bibliographical references.

Thesis (Ph. D.)--University of Washington, 2000. / Vita. Includes bibliographical references (leaves 107-111).

The Texas Department of Transportation (TxDOT) uses the Texas Condition Assessment Program (TxCAP) to measure and compare the overall road maintenance conditions among its 25 districts. TxCAP combines data from three existing subsystems: the Pavement Management Information System (PMIS), which scores the condition of pavement; the Texas Maintenance Assessment Program (TxMAP), which evaluates roadside conditions; and the Texas Traffic Assessment Program (TxTAP), which evaluates the condition of signs, work zones, railroad crossings, and other traffic elements to get an overall picture of the condition of state roads. As a result, TxCAP provides a more comprehensive assessment of the interstate and non-interstate highways. However, the scores for each of the subsystems are based on data of different sample sizes, accuracy, and levels of variations, making it difficult to decide if the difference between two TxCAP score is a true difference or measurement error. Therefore, whether the use of TxCAP is an effective and consistent means to measure the TxDOT roadway maintenance conditions raises concerns and needs to be evaluated. In order to achieve this objective, statistical analyses of the system were conducted in two ways: 1) to determine whether sufficient samples are collected for each of the subsystems, and 2) to determine if the scores are statistically different from each other. A case study was conducted with a dataset covering the whole state from 2008 to 2010. The case study results show that the difference in scores between two districts are statistically significant for some of the districts and insignificant for some other districts. It is therefore recommended that TxDOT either compare the 25 districts by groups/tiers or increase the sample size of the data being collected to compare the districts as individual ones. / text

The work presented in this thesis aims to further the understanding and implementation of the Baculovirus Expression Vector System (BEVS) for varied uses such as protein production and viral vector production. To this end, three projects have been presented, two of which deal with methods to quantify baculovirus titres and the last deals with tracking baculovirus transcripts in infected insect cells. The first project examined assumption-free analysis as a method for data analysis of Real Time PCR data in order to enable direct comparison of baculovirus titres between samples, without the need for a traditional standard curve. It concluded that assumption-free analysis was well suited for this purpose and fold differences of baculovirus titres of different samples obtained using this method corresponded to real differences in sample titres. The second project aimed to develop a cheap and reliable method for sample preparation for Real Time PCR which would remove the need for the use of commercially available extraction kits. Samples were subjected to various combinations of Triton X-100 at different concentrations and different numbers of freeze/thaw cycles in order to determine the combination which would provide the best baculovirus genome exposure. One of these combinations was found to be at least as good as commercially available kits in reliably extracting baculovirus DNA and providing baculovirus titres that are at least as accurate. The third project was a preliminary study examining the effects of multiplicity of infection on the levels of baculovirus Gp-64 transcript in insect cell culture. The study concludes that at high multiplicities of infection, there seems to be no increase in baculovirus transcripts when the multiplicity of infection is further increased. This study served to allow for familiarization with tracking transcript levels, and the principles and techniques demonstrated here will form the basis for an exhaustive future study on the same subject.

Traditional appearance based face recognition (FR) systems use gray scale images, however recently attention has been drawn to the use of color images. Color inputs have a larger dimensionality, which increases the computational cost, and makes the small sample size (SSS) problem in supervised FR systems more challenging. It is therefore important to determine the scenarios in which usage of color information helps the FR system. In this thesis, it was found that inclusion of chromatic information in FR systems is shown to be particularly advantageous in poor illumination conditions. In supervised systems, a color input of optimal dimensionality would improve the FR performance under SSS conditions. A fusion of decisions from individual spectral planes also helps in the SSS scenario. Finally, chromatic information is integrated into a supervised ensemble learner to address pose and illumination variations. This framework significantly boosts FR performance under a range of learning scenarios.