Prerequisites are embedded in most STEM curricula. However, the assumption that the content presented in these courses will improve learning in later courses has not been verified. Because a direct comparison of performance between students with and without required prerequisites is logistically difficult to arrange in a randomized fashion, we developed a novel familiarity scale, and used this to determine whether concepts introduced in a prerequisite course improved student learning in a later course (in two biology disciplines). Exam questions in the latter courses were classified into three categories, based on the degree to which the tested concept had been taught in the prerequisite course. If content familiarity mattered, it would be expected that exam scores on topics covered in the prerequisite would be higher than scores on novel topics. We found this to be partially true for “Very Familiar” questions (concepts covered in depth in the prerequisite). However, scores for concepts only briefly discussed in the prerequisite (“Familiar”) were indistinguishable from performance on topics that were “Not Familiar” (concepts only taught in the later course). These results imply that merely “covering” topics in a prerequisite course does not result in improved future performance, and that some topics may be able to removed from a course thereby freeing up class time. Our results may therefore support the implementation of student-centered teaching methods such as active learning, as the time-intensive nature of active learning has been cited as a barrier to its adoption. In addition, we propose that our familiarity system could be broadly utilized to aid in the assessment of the effectiveness of prerequisites.

The authors investigated the surgical and collateral effects on soft tissue of a carbon dioxide laser emitting at 9.3 micrometers. Specifically, incision widths and depths as well as effectiveness were studied. Three different laser modes were investigated: gated continuous wave, or Cw, Superpulse and OptiPulse (Medical Optics). Incision depths correlated positively with average power; higher powers produced deeper incisions. The gated Cw mode quickly produced wide, deep incisions; Superpulse achieved narrower, deep incisions; OptiPulse caused very narrow, shallow incisions. Collateral damage to adjacent tissues was reduced by a factor of about 2 using Superpulse, and by a factor of 10 using OptiPulse. A wide range of effects is achieved in soft tissue, depending on the laser parameter combination used.

No abstract

The impact of a prerequisite course was examined using both quantitative (exam data analyzed with a “familiarity” scale) and qualitative (surveys and semistructured interviews) data. These data affirmed a recent program change and highlighted the importance of collecting and analyzing student feedback in development of curricula.

Universities use prerequisites to regulate the path of students through a program or major. However, the impact of prerequisites on follow-up courses in anatomy and physiology is not well understood. If success in follow-up courses depends on completion of prerequisite courses, then students should earn higher grades on exam questions that assess prerequisite knowledge. To test this hypothesis, we investigated the potential impact of a required prerequisite human physiology lecture course on a followup human physiology laboratory course and a follow-up molecular pharmacology course. We also investigated the potential impact of a recommended prerequisite human physiology laboratory course on a follow-up human anatomy course. We assessed student exam performance in the follow-up courses based on their familiarity with the material from the required prerequisite course or the recommended prerequisite course. Our results were mixed and demonstrated limited performance gains in the follow-up courses despite overlap of material among the courses. These results suggest that prerequisite courses may not have a significant impact on the outcome of future related courses and that individual academic programs should evaluate the effectiveness of prerequisite courses in a local context.

Background:The purpose of this research was to evaluate the factors affecting the outcome of localized laser pulp surgery in the canine model. Study Design/Materials and Methods: Pulpal exposures 2 mm and 5 mm in diameter were prepared in eight healthy teeth in each of five dogs. The total of 40 teeth were left open to infection from the oral cavity for 3 hours or 72 hours; 2-3 mm of surface pulpal tissue were then removed using a fresh diamond bur or a CO 2 laser emitting @ 9.3 m, at 3.5 W average power in the Superpulse mode. Teeth were monitored clinically and radiographically by one blinded, pre-standardized clinician for 3 months. Results: Chi-square test and Fisher's Exact test (2-tail) results associated laser treatment with significantly better clinical and radiographic outcome (P < 0.001). Using regression analysis, duration of pulpal exposure to contamination by the oral environment was identified as primary determinant for treatment outcome within the laser-treated and control groups (P = 0.0018). Conclusion:Clinical preconditions significantly affect the outcome of pulp surgery treatments.

No abstract

These investigations were performed to determine thermal, histological and incisional effects in soft tissue of laser irradiation at 9.3um. Specifically, the consequences of varying pulse duration, interval and frequency, peak and average powers and energy densities were studied.In fresh pig's jaws, 6 standardised incisions, 3cm in length, were made per parameter using a template and motorised jig. Incisions were made at various standardised anatomical sites, and surface thennal events monitored using an IR camera. Laser parameters investigated: power: 1-11W, duty cycle: 10-90%, Pulse duration: 1-200ms, at gated continuous wave (Cw). Superpulse and OptiPuls& modes with 300us pulses were also investigated. Incision width and depth as well as collateral tissue effects were assessed statistically. They were directly related to the parameters used. Ease of incision and effects on underlying bone were also parameter-related. INTRODUCTIONOver the past 25 years, areas of routine CO' laser use in oro-facial surgery have progressed to include frenectomies, periodontal surgery, tumor resections and excision of lesions such as hyperplasias, papillomas, hemangiomas, lymphangiomas and mucoceles. Clinical and laboratory investigations have consistently confirmed the advantages of this tool: precision, minimal iniraoperative hemorrhage, sterilization of the surgical area and healing with minimal scarring, postoperative pain and swelling (1-5).The C02 laser emits light energy which is strongly absorbed by water, and therefore also by tissues with a high water content, such as the oral soft tissues. The absorbed energy causes vaporization of the intra-and exiracellular fluid and destruction of the cell membranes at the focal point (6,7), producing zones of incision or ablation. The energy applied to the target tissues will also affect, to a varying degree, adjacent or underlying tissue structures. The extent of collateral damage is related to the absorption characteristics of light in the tissues, and the laser parameters used. At a given wavelength, longer pulse durations will tend to result in higher levels of coagulation and necrosis in collateral structures, as they allow thermal energy to accumulate and penetrate to a greater extent than short, transient pulses. For clinical applications, the zone of thennal damage to adjacent structures should ideally be kept to a minimum, as it may impede wound healing, graft take, and reduce wound tensile strength, especially if it is extensive. Furthermore, laser-induced temperature increases can threaten the vitality of adjoining structures such as teeth, pulp or periodontium. Conversely, very short pulse durations may hinder haemostasis and reduce ease of incision or ablation; attempts at compensating for this phenomenon by increasing pulse frequency can result in an exacerbation of thermal effects.In the CO lasers traditionally available to clinical dentistry, light at lO.6u is delivered by means of an articulated arm or a hollow waveguide and a handpiece to the surgical site....