Differential Scanning Calorimetry (DSC) Analyses Of Superelastic And Nonsuperelastic Nickel-Titanium Orthodontic Wires

The purpose of this study was to determine the transformation temperatures for the austenitic, martensitic, and rhombohedral (R) structure phases in representative as-received commercial nitinol (NiTi) orthodontic wire alloys, to reconcile discrepancies among recent publications. Specimens were examined by differential scanning calorimetry (DSC) over a temperature range from approximately −170° C to 100° C, with a scanning rate of 10° C per minute. Two different pathways, with the intermediate R structure either absent or present, were observed for the transformation from martensitic to austenitic NiTi, whereas the reverse transformation from austenitic to martensitic NiTi always included the R structure. The enthalpy (ΔH) for the transformation from martensite to austenite ranged from 0.3 to 35 calories per gram. The lowest ΔH value for the nonsuperelastic Nitinol wire is consistent with a largely work-hardened, stable, martensitic microstructure in this product. The DSC results indicate that the transformation processes are broadly similar in superelastic, body-temperature shape-memory, and nonsuperelastic NiTi wires. Differences in bending properties for the NiTi orthodontic wires at room temperature and 37° C are due to the relative proportions of the metallurgical phases in the microstructures

The effect of mental models on creating organizational alignment around a change vision

The communication of an organizational change vision is a key to the success of organizational transformation. Theorists have prescribed models of how to make change vision communication successful but these models have no empirical data to support them. The purpose of this study was to explore the efficacy of change agents in communicating a change vision that compels employees to accept a perception of reality (mental model) that aligned with the change agents\u27 vision. A case study of the merger of two metropolitan agencies was conducted to examine the relationship between the communication of a change vision and its effect on organizational change. The primary change agent and several organizational members affected by the transformation were interviewed. Primary and secondary organizational documents concerning the merger were collected. Mental models from organizational members were compared for similarity to the change agent\u27s vision. Written and oral materials communicating the change vision were analyzed using Automap text analysis software as a measure of effectiveness and to determine which type of communication was most effective. Findings suggest that the change agent\u27s vision was poorly defined and communicated yet the transformation succeeded because organizational members created their own compensating change vision. Social change implications of this study may include challenging unproductive methods of organizational change that have wasted resources and led to organizational misalignment. A better understanding of the communication of change visions will lead to cost savings and more effective and efficient change efforts that benefit managers, employees and the customers of public agency services

Biocompatibility of Dental Amalgams

Objective. The purpose of this review paper is to review the literature regarding the toxicology of mercury from dental amalgam and evaluate current statements on dental amalgam. Materials and Methods. Two key-words “dental amalgam” and “toxicity” were used to search publications on dental amalgam biocompatibility published in peer-reviewed journals written in English. Manual search was also conducted. The most recent declarations and statements were evaluated using information available on the internet. Case reports were excluded from the study. Results. The literature show that mercury released from dental amalgam restorations does not contribute to systemic disease or systemic toxicological effects. No significant effects on the immune system have been demonstrated with the amounts of mercury released from dental amalgam restorations. Only very rarely have there been reported allergic reactions to mercury from amalgam restorations. No evidence supports a relationship between mercury released from dental amalgam and neurological diseases. Almost all of the declarations accessed by the internet stated by official organizations concluded that current data are not sufficient to relate various complaints and mercury release from dental amalgam. Conclusions. Available scientific data do not justify the discontinuation of amalgam use from dental practice or replacement with alternative restorative dental materials

Pharmacogenetics and Age-Related Macular Degeneration

Pharmacogenetics seeks to explain interpatient variability in response to medications by investigating genotype-phenotype correlations. There is a small but growing body of data regarding the pharmacogenetics of both nonexudative and exudative age-related macular degeneration. Most reported data concern polymorphisms in the complement factor H and age-related maculopathy susceptibility 2 genes. At this time, the data are not consistent and no definite conclusions may be drawn. As clinical trials data continue to accumulate, these relationships may become more apparent

The American Psychological Association’s Guidelines for Child Custody Evaluations in Family Law Proceedings: Implications for the Courts

Whether they directly preside over such matters or not, all judges are aware that child custody cases are among the most contentious, nerve-wracking, and costly proceedings in our entire legal system. The most aggrieved and well-heeled of litigants are likely to up the ante by enlisting psychologists as expert witnesses—even when the Court has already found it necessary to do so on its own. American Psychological Association (APA) Guidelines exist to encourage best practices for these witnesses, and to help them to avoid commonly encountered pitfalls. This article addresses how the Court can best access, interpret, and reinforce the latest revision of these Guidelines for the benefit of parties, counsel, and judges alike

Comparisons of Speech Anxiety in Basic Public Speaking Courses: Are Intensive or Traditional Semester Courses Better?

Students of public speaking are often asked if a basic public speaking course helped them deal with their fear of public speaking. Comparisons of anxiety levels between students enrolled in traditional 15-week semester courses and those enrolled in intensive courses has received little attention. The purpose of this exploratory, quasi-experimental study was to determine whether students enrolled in intensive public speaking courses reported higher levels of communication apprehension, i.e., speech anxiety. Participants were 722 undergraduate students who completed the Personal Report of Public Speaking Anxiety instrument. The findings indicated that students enrolled in intensive public speaking courses had significant moderate communication apprehension scores compared to students enrolled in 15-week semester courses. It is argued that the study indicates that there are factors that should be explored in further research on intensive public speaking courses

Determining Current Practices for College and University Electronic Records Management Programs: Follow-up Interviews

The establishment and implementation of electronic records management (ERM) programs in academic institutions has become a focus of numerous studies in recent years. The interviews conducted for this study were follow-ups to a study completed between 2005-2009 by Lisl Zach and Marcia Frank Peri. The objective of Zach and Peri's study was to gain an understanding of the work currently being done with ERM programs in college and university archives. The purpose of this study was to follow-up on the original interviews to determine how much, if any, progress had been made in the last four years. Analysis of the information collected during the interviews indicates that significant progress has not been made since the original interviews. The majority of the participants recognize the importance of ERM programs and are eager to implement these programs, however, a lack of support and training prevents these programs from being established and successful

Amplification Dynamics of Platy-1 Retrotransposons in the Cebidae Platyrrhine Lineage

Platy-1 elements are Platyrrhine-specific, short interspersed elements originally discovered in the Callithrix jacchus (common marmoset) genome. To date, only the marmoset genome has been analyzed for Platy-1 repeat content. Here, we report full-length Platy-1 insertions in other New World monkey (NWM) genomes (Saimiri boliviensis, squirrel monkey; Cebus imitator, capuchin monkey; and Aotus nancymaae, owl monkey) and analyze the amplification dynamics of lineage-specific Platy-1 insertions. A relatively small number of full-length and lineage-specific Platy-1 elements were found in the squirrel, capuchin, and owl monkey genomes compared with the marmoset genome. In addition, only a few older Platy-1 subfamilies were recovered in this study, with no Platy-1 subfamilies younger than Platy-1-6. By contrast, 62 Platy-1 subfamilies were discovered in the marmoset genome. All of the lineage-specific insertions found in the squirrel and capuchin monkeys were fixed present. However, similar to 15% of the lineage-specific Platy-1 loci in Aotus were polymorphic for insertion presence/absence. In addition, two new Platy-1 subfamilies were identified in the owl monkey genome with low nucleotide divergences compared with their respective consensus sequences, suggesting minimal ongoing retrotransposition in the Aotus genus and no current activity in the Saimiri, Cebus, and Sapajus genera. These comparative analyses highlight the finding that the high number of Platy-1 elements discovered in the marmoset genome is an exception among NWM analyzed thus far, rather than the rule. Future studies are needed to expand upon our knowledge of Platy-1 amplification in other NWM genomes