University of Missouri

About: University of Missouri is a education organization based out in Columbia, Missouri, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 41427 authors who have published 83598 publications receiving 2911437 citations. The organization is also known as: Mizzou & Missouri-Columbia.

An Overview of Chemical Processes That Damage Cellular DNA: Spontaneous Hydrolysis, Alkylation, and Reactions with Radicals

Abstract: The sequence of heterocyclic bases on the interior of the DNA double helix constitutes the genetic code that drives the operation of all living organisms. With this said, it is not surprising that chemical modification of cellular DNA can have profound biological consequences. Therefore, the organic chemistry of DNA damage is fundamentally important to diverse fields including medicinal chemistry, toxicology, and biotechnology. This review is designed to provide a brief overview of the common types of chemical reactions that lead to DNA damage under physiological conditions.

Impaired diastolic function and coronary reserve in genetic hypertension. Role of interstitial fibrosis and medial thickening of intramyocardial coronary arteries.

Abstract: Left ventricular hypertrophy (LVH) in rats with genetic hypertension is accompanied by abnormal myocardial diastolic stiffness and impaired coronary reserve. Whether these functional defects are related to a structural remodeling of the myocardium that includes an interstitial and perivascular fibrosis, myocyte hypertrophy, and medial thickening of intramyocardial coronary arteries is uncertain. To address these issues, 14-week-old male spontaneously hypertensive rats with established hypertension and LVH were treated with low-dose (SLO group: 2.5 mg/kg/day, n = 11) or high-dose (SHI group: 20 mg/kg/day, n = 9) oral lisinopril for 12 weeks to sustain hypertension and LVH or to normalize arterial pressure and myocardial mass, respectively. When SHI and SLO groups were compared with age- and sex-matched 26-week-old untreated spontaneously hypertensive rats (n = 11) and normotensive Wistar-Kyoto rats (n = 9), we found 1) normalization of blood pressure (p less than 0.005) and complete regression of LVH (p less than 0.005) in the SHI group and no significant blood pressure or LVH reduction in the SLO group, 2) complete regression of morphometrically determined myocardial interstitial and perivascular fibrosis in SHI and SLO groups (p less than 0.025) associated with normalization of diastolic stiffness, measured in the isolated heart (p less than 0.025), and 3) regression of medial wall thickening of intramyocardial coronary arteries only in the SHI group (P less than 0.005), accompanied by a normalization of coronary vasodilator reserve to adenosine (p less than 0.005). Thus, interstitial fibrosis and not LVH is responsible for abnormal myocardial diastolic stiffness, whereas medical wall thickening of intramyocardial resistance vessels, influenced by arterial pressure, is associated with impaired coronary reserve.

The fallacy of placing confidence in confidence intervals

Abstract: Interval estimates – estimates of parameters that include an allowance for sampling uncertainty – have long been touted as a key component of statistical analyses. There are several kinds of interval estimates, but the most popular are confidence intervals (CIs): intervals that contain the true parameter value in some known proportion of repeated samples, on average. The width of confidence intervals is thought to index the precision of an estimate; CIs are thought to be a guide to which parameter values are plausible or reasonable; and the confidence coefficient of the interval (e.g., 95 %) is thought to index the plausibility that the true parameter is included in the interval. We show in a number of examples that CIs do not necessarily have any of these properties, and can lead to unjustified or arbitrary inferences. For this reason, we caution against relying upon confidence interval theory to justify interval estimates, and suggest that other theories of interval estimation should be used instead.

A Terror Management Analysis of the Psychological Functions of Religion

Abstract: From a terror management theory (TMT) perspective, religion serves to manage the potential terror engendered by the uniquely human awareness of death by affording a sense of psychological security and hope of immortality. Although secular beliefs can also serve a terror management function, religious beliefs are particularly well suited to mitigate death anxiety because they are all encompassing, rely on concepts that are not easily disconfirmed, and promise literal immortality. Research is reviewed demonstrating that mortality salience produces increased belief in afterlife, supernatural agency, human ascension from nature, and spiritual distinctions between mind and body. The social costs and benefits of religious beliefs are considered and compared to those of secular worldviews. The terror management functions of, and benefits and costs associated with, different types of religious orientation, such as intrinsic religiosity, quest, and religious fundamentalism, are then examined. Finally, the TMT analysis is compared to other accounts of religion.

The effects of argumentation scaffolds on argumentation and problem solving

Abstract: An important skill in solving problems, especially ill-structured problems, is the production of coherent arguments to justify solutions and actions. Because direct instruction in argumentation has produced inconsistent results and cannot effectively support online learning, we examined the use of online argumentation scaffolds to engage and support coherent argumentation. In this study, we showed that providing a constraint-based argumentation scaffold during group problem-solving activities increased the generation of coherent arguments. The same scaffold further resulted in significantly more problem-solving actions during collaborative group discussions. The effects of the scaffold varied for problem type. Groups that solved ill-structured problems produced more extensive arguments. When solving ill-structured problems, students need more argumentation support because of the importance of generating and supporting alternative solutions. The close relationship between argumentation and problem solving, especially ill-structured problem solving, is significant. The effects of the argument scaffold consistently transferred to the production of arguments during individual problem solving. Students used the familiar argumentation scripts while solving problems individually.