Assessment of cortical bone microdamage following insertion of microimplants using optical coherence tomography: a preliminary study

Objectives

The study was done to evaluate the efficacy of optical coherence tomography (OCT), to detect and analyze the microdamage occurring around the microimplant immediately following its placement, and to compare the findings with micro-computed tomography (μCT) images of the samples to validate the result of the present study.

Methods

Microimplants were inserted into bovine bone samples. Images of the samples were obtained using OCT and μCT. Visual comparisons of the images were made to evaluate whether anatomical details and microdamage induced by microimplant insertion were accurately revealed by OCT.

Results

The surface of the cortical bone with its anatomical variations is visualized on the OCT images. Microdamage occurring on the surface of the cortical bone around the microimplant can be appreciated in OCT images. The resulting OCT images were compared with the μCT images. A high correlation regarding the visualization of individual microcracks was observed. The depth penetration of OCT is limited when compared to μCT.

Conclusions

OCT in the present study was able to generate high-resolution images of the microdamage occurring around the microimplant. Image quality at the surface of the cortical bone is above par when compared with μCT imaging, because of the inherent high contrast and high-resolution quality of OCT systems. Improvements in the imaging depth and development of intraoral sensors are vital for developing a real-time imaging system and integrating the system into orthodontic practice.

     

One Policy,Disparate Reactions: Institutional Responses in Florida’s Developmental Education Reform

This paper seeks to better understand how community colleges in Florida planned to implement a new sweeping state policy pertaining to developmental education. Via a cluster analysis, we identify three distinct patterns in the ways in which the colleges responded to the policy: reformers, responders, and resisters. Further, we find that these patterns are related to the extent to which individual colleges had previously enacted campus-based developmental education reform measures, the magnitude of students previously enrolled in developmental education, and the colleges’ perceptions of the effectiveness of the policy.     

Reading,Writing, and English Course Pathways when Developmental Education is Optional: Course Enrollment and Success for Underprepared First-time-in-College Students

Academic underpreparedness is an issue for many first-time-in-college students, particularly those entering community colleges. Whereas many underprepared students enroll in developmental education, research has indicated that traditional remediation may not increase students’ chances for success. Therefore, states and colleges have begun to implement new course placement strategies to increase the accuracy of initial course placement and new instructional approaches to better serve their developmental students. Specifically, in 2013, the state of Florida passed Senate Bill 1720 which redesigned developmental coursework and placement policies across the Florida College System. The reform lifted developmental education placement exam testing and course enrollment requirements for certain exempt students, irrespective of prior academic preparation or achievement. The current study focuses on these exempt students—those who had the option to bypass developmental education—who were also underprepared, and their initial course selection and subsequent success in their gateway (introductory college-level) English course. Using statewide student-level data and logistic regression techniques, the results indicated that level of preparation was related to students’ course enrollment and gateway English course success. Students slightly underprepared in reading or writing were more likely than severely underprepared students to enroll in the gateway English class, relative to a developmental reading or writing course. In reading and writing, slightly underprepared students were more likely to pass English, relative to severely underprepared students. The authors consider the findings in light of recent national changes to developmental education and offer recommendations for policy and practice.     

Dynamic characteristics of mental models and dynamic visual displays

Mental models are hypothetical constructs for explaining human cognitive processes of understanding external reality, translating the reality into internal representation and utilizing it in problem solving. Three experiments were conducted to investigate important characteristics of mental models, their influence on task performance, and instructional strategies facilitating their formation. The experiments were conducted in computer-based training environments designed to teach troubleshooting electronic logic circuits. The results suggested: (a) dynamic characteristics of mental models are important for solving problems if understanding functional behaviors of the system is required to perform the task; (b) dynamic characteristics of mental models are determined primarily by subjects' understanding of the system features and functions more than by the visually presented training contents of the system; and (c) motion simulating system functions in visual displays is more effective than static visual displays in facilitating the formation of dynamic characteristics of mental models. Consequently, dynamic visual displays are more effective than static visual displays for teaching electronic troubleshooting skills. These findings provide direct implications for the development of training programs.     

Early Education Essentials: Validation of Surveys Measuring Early Education Organizational Conditions

Research Findings: The Early Education Essentials surveys use teacher and parent perceptions to measure 6 organizational conditions of early childhood education programs, extending and complementing existing measures of early childhood care and education (ECE) quality constructs. This study tests the reliability and concurrent validity of the Early Education Essentials in 81 school- and community-based ECE sites in a large Midwestern city selected using a stratified random sampling method. Using a Rasch item response theory model, scales were created; theory and exploratory factor analyses combined scales into higher level constructs called essentials. Multilevel models took into account individual measurement error to create site-level essential scores and assessed relationships between programs’ essential scores and site-level teacher–child interactions scores and student attendance. Findings suggest that the Early Education Essentials is reliable in multiple ECE settings; it is sensitive to site-level differences; and some, but not all, organizational conditions measured are associated in expected directions with site-level metrics indicative of center-based ECE quality. Practice or Policy: The Early Education Essentials has the potential to provide leaders and practitioners with actionable data about organizational supports that enable ECE practitioners to be more effective in their daily work with children and families.     

HUMAN SUBJECTS AND COGNITIVE AGING RESEARCH: A UNIQUE SOLUTION TO A PERENNIAL PROBLEM

A fundamental concern of cognitive aging researchers is to find a representative sample of healthy, older adults who are willing to participate in experimental research. There are essentially two methods for marshalling a sizable body of older research participants. One can solicit the aid of local community‐dwelling adults through civic and church‐related organizations. Alternatively, one can travel to specific locations where elderly people are likely to congregate, for example, a retirement community. In this article, we describe our experiences with these two methods of research‐participant recruitment. The processes involved in both securing and utilizing a local body of research volunteers are presented first. We then discuss two subject‐testing expeditions outside of the university environment that have been highly successful. In the final section, we contrast selected demographic characteristics of our local and off‐site research volunteers and discuss the implications of differences between these two populations for conducting research with aged people.     

Validation of the Korean version Gender Role Conflict Scale for Adolescents

The objective of this study was to examine the usefulness of the Korean version of the Gender Role Conflict Scale for Adolescents (GRCS-A; Blazina et al. 2005) in Korea. Korean high school students (N = 374) completed the K-GRCS-A. Results of confirmatory factor analysis supported the original 4-factor structures. Reliability was acceptable to satisfactory limits. Further evidence of construct validity was found in modest correlations with psychological well-being variables. Taken together, this study sustained the utility of the K-GRCS-A.     

Communication practices in Korea

The communication practices of Koreans are explored which are divergent from those employed elsewhere in the world. Distinction in social behavior impinging on communication include Confucianistic ethics, filial piety, age, gender, and hierarchical structure. Verbal and nonverbal differences relate to maintaining harmony in interpersonal relationships. The essay concludes with analyses from six research reports comparing Korean communication styles to those in other cultures.