STATISTICAL METHODS FOR ANALYSIS OF CANCER CHEMOPREVENTION EXPERIMENTS

The experimental systems studied in this dissertation are designed to investigate the effect of diet on incidence rates of cancer. These investigations involve the chemical induction of tumors in experimental animals in order to test the chemopreventative effects of various substances. Both tumor number and rate of tumor development are important in evaluating the effects of a chemopreventative agent. This is made difficult, when multiple tumors occur, by the confounding of the number of induced tumors and their time of detection. This confounding occurs because experiments are terminated before all induced tumors have been detected. Fewer tumors observed in one treatment group, as compared to another, may be the result of a decreased number of induced tumors, a slowing of tumor growth rate, or both. Current statistical procedures do not consider this factor and therefore, do not reliably discriminate between these biologically different possibilities. This study provides the cancer researcher with statistical procedures which directly address this problem of confounding of tumor number and detection time distributions. The method of maximum likelihood is used to simultaneously estimate the parameters characterizing these two confounded distributions. In order to compare treatments the likelihood ratio test is used to detect overall group differences and a technique is described to isolate which factor(s) (tumor number and/or rate of development) is(are) contributing to a group difference. Numerical results are used to discuss the sensitivity of the estimation procedure subject to changes in the experimenter controlled variables in order to design more accurate and efficient experiments and better utilize resources

Towards a Novel Tournament Scheduling Algorithm and Statistical Measure of Team Equity in Large Scale Forensic Tournaments

Business items raised at recent national forensics tournaments regarding scheduling seem to be based around issues of an increased number of competitors and a trend for some schools to have a disproportionate amount of competitors in a single event. This paper examines the stated goals in scheduling a tournament as a device that measures the ability of competitors. Stemming from these goals, this paper proposes a novel random scheduling algorithm capable of scheduling a large number of competitors in an individual event. After implementing this algorithm, its performance is measured in relation to its ability to schedule a tournament comparable with given national level competitions. This paper further suggests that there may be a need to establish a method for measuring the fairness of a schedule. This paper concludes with the recommendation that the means of scheduling the most important tournaments be reexamined and that tournaments describe the means by which they will be scheduled

In vitro selective growth-inhibitory effect of 8-hydroxyquinoline on Clostridium perfringens versus Bifidobacteria in a medium containing chicken ileal digesta

Clostridium perfringens-induced necrotic enteritis is generally controlled by antibiotics. However, because of increasing antibiotic resistance, other antibacterial agents are required, preferably ones that do not affect the beneficial intestinal microbiota of the host. This study evaluated the in vitro selective growth-inhibitory effect of 8-hydroxyquinoline (8HQ) on C. perfringens vs. bifidobacteria in a medium containing chicken ileal digesta. Prior to the experiments, the minimum inhibitory concentrations of 8HQ and penicillin G were determined by broth microdilution assay. The minimum inhibitory concentration values of 8HQ for C. perfringens were 16-32 times lower than the values for bifidobacteria. Treatment of autoclaved and non-autoclaved chicken ileal digesta with 8HQ showed a selective anticlostridial effect. After incubation of C. perfringens with autoclaved ileal digesta for 3 h, all 8HQ concentrations tested (32-2048 mu g/mL) significantly reduced C. perfringens bacterial count. In contrast, the same treatment had no or only a slight effect on bifidobacteria counts. Unlike 8HQ, penicillin G did not exhibit any selectivity. Similar results were obtained after incubation for 24 h. In non-autoclaved ileal digesta, all 8HQ concentrations tested significantly reduced C. perfringens bacterial counts after incubation for 30 min and 3 h, while no effect was observed on bifidobacteria. These results suggest that 8HQ may serve as a prospective veterinary compound for use against necrotic enteritis in poultry

The Virtue of Shame in Moral Development An Aristotelian Perspective

Aristotle touts the importance of performing virtuous actions in order to have a virtuous character. Yet, reason is necessary for an individual to actively change their own behavior. Aristotle believes that children are too young to have developed reason, so we may wonder how are they to become virtuous. The answer I offer is shame. Shame is a painful emotion that causes one to believe that, by acting poorly, we have lowered our worth in the eyes of those we respect and admire. I argue that shame effectively changes behavior in children because it is attached to a stigma of dishonor and the pain of rebuke to activities, which they might otherwise do. Shame encourages children to reform their behavior by leading them to forgo the pleasure of one activity so that they do not have to experience the pain of displeasing those who they hold in high regard, their peers, and themselves. Remarkably, shame appears to be the only emotion within Aristotle\u27s framework that has the ability to develop virtue and morality in children without reason

In vitro growth-inhibitory activity of Calophyllum inophyllum ethanol leaf extract against diarrhoea-causing bacteria

Purpose: To investigate the in vitro growth-inhibitory effect of Calophyllum inophyllum, a medicinal plant traditionally used to cure gastrointestinal disorders caused by diarrhoea-causing bacteria.Methods: The minimum inhibitory concentration (MIC) of C. inophyllum ethanol leaf extract was determined against six diarrhoea-causing bacteria, namely, Clostridium difficile infant, Clostridium perfringens, Enterococcus faecalis, Escherichia coli, Listeria monocytogenes, and Salmonella enterica. The effect of the plant extract on bacterial growth kinetics was further evaluated by slightly modified broth microdilution method.Results: The plant extract showed significant inhibitory activity against C. perfringens and L. monocytogenes (MIC = 128 μg/mL) followed by C. difficile (MIC = 512 μg/mL). Monitored growth curves also showed that the plant extract at ½ MIC inhibits bacterial growth by distinct extension of the lag phase or suppression of the whole growth rate in C. difficile and L. monocytogenes, respectively.Conclusion: These results demonstrate the significant anti-clostridial and anti-listerial activities of C. inophyllum ethanol leaf extract. Thus, the extract seems to be a promising material for the development of new antibacterial agents.Keywords: Calophyllum inophyllum, Alexandrian laurel, Intestinal infections, Antibacterial activity, Anticlostridial, Anti-listeria

Use of Ultrasound Measurements to Direct Laparoscopic Pyloromyotomy in Infants

Preoperative ultrasound measurement of pyloric length to determine laparoscopic pyloromyotomy appears to minimize the risk of incomplete pyloromyotomy

In vitro antimicrobial activity of plants used in traditional medicine in Gurage and Silti Zones, south central Ethiopia

Background: To overcome the escalating problems associated with infectious diseases and drug resistance, discovery of new antimicrobials is crucial. The present study aimed to carry out in vitro antimicrobial analysis of 15 medicinal plant species selected according to their traditional medicinal uses in Gurage and Silti Zones, south central Ethiopia. Methods: Ethanol extracts of various plant parts were investigated for their antimicrobial activity against 20 bacterial and one yeast strains. The minimum inhibitory concentration (MIC) was determined by broth microdilution method. Results: Asparagus africanus, Guizotia schimperi, Lippia adoensis var. adoensis and Premna schimperi were active against Candida albicans, Enterococcus faecalis and Staphylococcus aureus at a concentration of 512 mu g/ml or lower. Strong antibacterial activity (MIC >= 128 mu g/ml) was observed for G. schimperi extract against 17 resistant and sensitive Staphylococcus strains, at a concentration comparable to standard antibiotics. Moreover, this extract showed higher antibacterial activity for the test against S. aureus ATCC 33591, ATCC 33592, SA3 and SA5 strains (128-256 mu g/ml) than oxacillin (512 mu g/ml). Conclusions: The study revealed in vitro antibacterial activity of plants used in folk medicine in south central Ethiopia. The usefulness of these plants, in particular of G. schimperi, should be confirmed through further phytochemical and toxicity analyses