Effect of Toothbrushing On Shade and Surface Roughness of Extrinsically Stained Pressable Ceramics

Statement of problem The effect of toothbrushing on extrinsically stained pressable ceramic materials is unknown. Purpose The purpose of this in vitro study was to investigate the effects of toothbrushing on the shade and surface roughness of extrinsically stained, pressable ceramics. Material and Methods Two materials, leucite-based (IPS Empress Esthetic [EE]; Ivoclar Vivadent AG) and lithium disilicate-based ceramic (IPS e.max Press [EP]; Ivoclar Vivadent AG), were studied. For each material, 24 disk-shaped specimens, 10 mm (diameter)×3 mm (height) were fabricated. Three different methods (n=8) of applying extrinsic stains were performed on each material: glazed only (G, control group); stained then glazed (SG); and stained and glazed together (T). The specimens were brushed with a multistation brushing machine under a load of 1.96 N at a rate of 90 strokes per minute with a soft and straight toothbrush (Oral-B #35) and a 1:1 toothpaste and distilled water slurry. Shade and roughness were measured at baseline and at 72, 144, 216, and 288 hours, which is equivalent to 3, 6, 9, and 12 years of simulated toothbrushing for 2 minutes twice a day. A repeated measures ANOVA with staining technique as a fixed factor was used to evaluate shade and roughness (α=.05). Results For EE groups, no significant change was found after 12 years of simulated toothbrushing regarding shade and surface roughness, irrespective of staining techniques (P\u3e.05). However, EP groups demonstrated a significant shade change and an increase in surface roughness after 12 years of simulated toothbrushing. Shade change was found to depend on the method of applying stain. For the EP-SG technique, a significant shade change was observed only at the 9- to 12-year interval (P=.047). However, the EP-T technique demonstrated a significant difference in shade between baseline and 3 years (P=.005) and in the 6- to 9-year interval (P=.005). Surface roughness was only significantly affected at baseline and 3 years for the EP-T group (P=.005). Conclusions For the shade and surface roughness of the EE groups, no statistically significant difference was found after 12 years of toothbrushing, irrespective of the staining technique. The shade and surface roughness of the EP groups were significantly statistically affected by toothbrushing time; only shade changes were found to depend on technique

Identification of the orphan gene Prod 1 in basal and other salamander families.

The urodele amphibians (salamanders) are the only adult tetrapods able to regenerate the limb. It is unclear if this is an ancestral property that is retained in salamanders but lost in other tetrapods or if it evolved in salamanders. The three-finger protein Prod 1 is implicated in the mechanism of newt limb regeneration, and no orthologs have been found in other vertebrates, thus providing evidence for the second viewpoint. It has also been suggested that this protein could play a role in salamander-specific aspects of limb development. There are ten families of extant salamanders, and Prod 1 has only been identified in two of them to date. It is important to determine if it is present in other families and, particularly, the basal group of two families which diverged approximately 200 MYA

BCHS 2526 Health Disparities Research: Methods and Interventions

This course will examine the challenges and methods in the implementation of health disparities research and interventions. It is intended to both complement and expand the knowledge gained in other BCHS courses by focusing specifically on minority/underserved populations. The course will explore readings and foster discussions that will include: ethics and research in minority/underserved communities; issues, barriers and facilitators to engaging minority/underserved communities in health research; examining basic research questions in minority health; understanding the application of research findings to program development; how to integrate theory and research, and issues and challenges of program implementation. An overarching goal is to increase awareness and knowledge of research on minority health, as well as unique issues to consider when engaging in public health research and practice in these communities. The purpose of this class is to introduce basic issues, challenges, and opportunities that are encountered in health disparities research and interventions. Current research and resources from minority health and health disparities literature will provide the background for student assignments

An experimental test of prejudice about foreign people

This paper o¤ers two related issues: (i ) an applications of beliefs about the cooperative behavior of others to policy-oriented issues, (ii ) a method of explor- ing prejudices (toward others) where interviewees are oblivious of its purpose. We studied contributions and guesses about others?contributions through an experimental game. Prejudice is examined as an implicitly held belief by a Spanish college student towards any of the speci?ed foreign population groups (i.e. the Asians, the Africans, the Latin Americans and the Westerners). The results show that: at the individual level, there exists some subjects that harbor strong positive (and negative) prejudices toward the foreigners. The prejudice models ?tted also show that: own contributions, femaleness, individual wealth; and beliefs about income status, cultural status, religious intensity, societal co- operation and political orientation have strong in?uences on racial prejudice.Beliefs, Prejudice, Public Goods Game

Funneled angle landscapes for helical proteins

We use crystallographic data for four helical iron proteins (cytochrome c-b₅₆₂, cytochrome c′, sperm whale myoglobin, human cytoglobin) to calculate radial and angular signatures as each unfolds from the native state stepwise though four unfolded states. From these data we construct an angle phase diagram to display the evolution of each protein from its native state; and, in turn, the phase diagram is used to construct a funneled angle landscape for comparison with the topography of its folding energy landscape. We quantify the departure of individual helical and turning regions from the areal, angular profile of corresponding regions of the native state. This procedure allows us to identify the similarities and differences among individual helical and turning regions in the early stages of unfolding of the four helical heme proteins

The role of personal involvement and responsibility in dictatorial allocations: A classroom experiment

Paper was revised on 2009-11-11.-- Published as article in: Rationality and Society (2009), 21(2), 1-24.fairness, dictator game, moral cost

Modeling and Analysis of Germ Layer Formations Using Finite Dynamical Systems

The development of an embryo from a fertilised egg to a multicellular organism proceeds through numerous steps, with the formation of the three germ layers (endoderm, mesoderm, ectoderm) being one of the first. In this paper we study the mesendoderm (the tissue that collectively gives rise to both mesoderm and endoderm) gene regulatory network for two species, \textit{Xenopus laevis} and the axolotl (\textit{Ambystoma mexicanum}) using Boolean networks. We find that previously-established bistability found in these networks can be reproduced using this Boolean framework, provided that some assumptions used in previously-published differential equations models are relaxed. We conclude by discussing our findings in relation to previous work modeling gene regulatory networks with Boolean network models