Algorithms & Techniques for Studying In Vitro Oral Biofilms

Dental caries and periodontal disease affect billions of people annually with a global prevalence estimated at 35% and 11%, respectively. Oral biofilms that develop on tooth surfaces and within gingival crevices are a major risk factor. Disease prevention efforts are focused on controlling the overgrowth of biofilms by removal (e.g., toothbrushing), antimicrobial-containing mouth rinses, and dentifrices. A number of laboratory (in vitro) models of biofilms are used to understand how biofilms develop and their response to mouth rinses and dentifrices. However, there are two major limitations to currently available in vitro biofilm model systems. First, there is no biofilm model system validated for the development of representative dental plaque biofilms. Second, there is no standard approach to analyze biofilm images. Current techniques rely on thresholding algorithms that are not designed for fluorescent images. Combined, these limitations can lead to differences in quantification of biofilm outcomes and thus raise questions regarding the relevance of the model system to the “real-world”. This dissertation seeks to bridge the gap between current laboratory techniques and software algorithms and provide investigators additional tools to conduct in vitro oral biofilm studies. First, a distillation of model systems relevant to modern in vitro oral biofilm research is provided. Second, we adapted one of these described model systems, the 24-well BiofluxTM to reproducibly grow multi-species dental biofilms. An objective imaging strategy was further developed to capture all biofilm architectural features. Before analyzing biofilm images, a novel thresholding algorithm, the biovolume elasticity method (BEM), was developed to threshold fluorescent signal. Finally, a software package called Biofilm Architecture Inference Tool (BAIT) was built and evaluated to measure core architectural features of biofilms. In summary, this dissertation describes the modification of a 24-well Bioflux system that facilitates the reproducible development of biofilms. For better visualization and quantification of in vitro biofilms, a novel thresholding algorithm was described. Finally, a software package integrating the BEM thresholding method was developed to measure architectural outcomes. The work presented here represents the outcome of a combinatorial approach to redefine techniques to study oral biofilms, and may also be relevant to the study of biofilms that exist outside the oral cavity.PHDEpidemiological ScienceUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttps://deepblue.lib.umich.edu/bitstream/2027.42/145880/1/tingluo_1.pd

Colour Design for Carton-Packed Fruit Juice Packages

The present research studies the relationships between observers’ expectations for 7 fruit juice packages and the colour design of the package. To do this, a two-stage experiment was conducted. At the first stage, we studied perceived colours for the fruit images shown on each package. At the second stage, fruit juice packages with 20 package colours were rated using 5 bipolar scales: colour harmony, preference, freshness, naturalness and product quality. The experimental results show that the observers tended to perceive fruit image colours lighter and more saturated than those measured using colour measuring instruments. Using factor analyses, we classified the 5 bipolar scales into 2 factors: Product Preference and Freshness. Package colour design was found to have significant impacts on both factors: similarity in chroma and hue between package colour and perceived fruit colour would lead to high product expectations. Keywords: colour design; colour harmony; product expectation; perceived image colour</p

How capital structure affects business performance in Chinese listed commercial banks

In the end of 2006, China realized the opening of financial market, thus Chinese commercial banks have to face the global competitors. The business performance of banks is the overall reflection of competence; however, the performance of Chinese banking industry is still weaker. According to some theoretical basis of capital structure, capital structure affects overall business performance by influencing the corporate governance of corporations. The capital structure of commercial banks also plays a vital role in achieving the financial goals and moderate operation. Thus this study aims to research how commercial banks’ capital structure affects business performance in China, and gives the recommendation to optimize the banks’ capital structure and improve business performance. This study employs penal data set in a sample of 14 Chinese listed commercial banks from 2005 to 2009. There are two indictors to measure the business performance: return on equity (ROE) and non-performing loan ratio (NPR). Considering the specificity of the banking industry, the study mainly focuses the effects of ownership structure (which includes ownership concentration, nature of owner and circulation stock proportion), supplementary capital and capital adequacy level on business performance. The results for return on equity indicate that proportion of top five shareholders (CR5) which is fairly significantly correlates with ROE positively. But the holding proportion of largest shareholder (CR1) is negative but no significantly affects ROE. Capital adequacy level negatively affects ROE. The results for non-performing loan show that CR1 and CR5 do not significantly affect NPR. The characteristic of the largest shareholder correlates with neither ROE nor NPR, the proportion of circulating stock affects business performance significantly. Finally, the proportion of supplementary capital also positively correlates with ROE and negatively affects NPR. Key words: bank capital structure, business performance, Chinese listed commercial bank