NEXUS/Physics: An interdisciplinary repurposing of physics for biologists

In response to increasing calls for the reform of the undergraduate science curriculum for life science majors and pre-medical students (Bio2010, Scientific Foundations for Future Physicians, Vision & Change), an interdisciplinary team has created NEXUS/Physics: a repurposing of an introductory physics curriculum for the life sciences. The curriculum interacts strongly and supportively with introductory biology and chemistry courses taken by life sciences students, with the goal of helping students build general, multi-discipline scientific competencies. In order to do this, our two-semester NEXUS/Physics course sequence is positioned as a second year course so students will have had some exposure to basic concepts in biology and chemistry. NEXUS/Physics stresses interdisciplinary examples and the content differs markedly from traditional introductory physics to facilitate this. It extends the discussion of energy to include interatomic potentials and chemical reactions, the discussion of thermodynamics to include enthalpy and Gibbs free energy, and includes a serious discussion of random vs. coherent motion including diffusion. The development of instructional materials is coordinated with careful education research. Both the new content and the results of the research are described in a series of papers for which this paper serves as an overview and context.Comment: 12 page

Focal therapy for prostate cancer: revolution or evolution?

The face of prostate cancer has been dramatically changed since the late 1980s when PSA was introduced as a clinical screening tool. More men are diagnosed with small foci of cancers instead of the advanced disease evident prior to PSA screening. Treatment options for these smaller tumors consist of expectant management, radiation therapy (brachytherapy and external beam radiotherapy) and surgery (cryosurgical ablation and radical prostatectomy). In the highly select patient, cancer specific survival employing any of these treatment options is excellent, however morbidity from these interventions are significant. Thus, the idea of treating only the cancer within the prostate and sparing the non-cancerous tissue in the prostate is quite appealing, yet controversial. Moving forward if we are to embrace the focal treatment of prostate cancer we must: be able to accurately identify index lesions within the prostate, image cancers within the prostate and methodically study the litany of focal therapeutic options available

The importance of context: an exploration of factors influencing the adoption of student-centered teaching among chemistry, biology, and physics faculty

Background: Research at the secondary and postsecondary levels has clearly demonstrated the critical role that individual and contextual characteristics play in instructors’ decision to adopt educational innovations. Although recent research has shed light on factors influencing the teaching practices of science, technology, engineering, and mathematics (STEM) faculty, it is still not well understood how unique departmental environments impact faculty adoption of evidence-based instructional practices (EBIPs) within the context of a single institution. In this study, we sought to characterize the communication channels utilized by STEM faculty, as well as the contextual and individual factors that influence the teaching practices of STEM faculty at the departmental level. Accordingly, we collected survey and observational data from the chemistry, biology, and physics faculty at a single large research-intensive university in the USA. We then compared the influencing factors experienced by faculty in these different departments to their instructional practices. Results: Analyses of the survey data reveal disciplinary differences in the factors influencing adoption of EBIPs. In particular, the physics faculty (n = 15) had primarily student-centered views about teaching and experienced the most positive contextual factors toward adoption of EBIPs. At the other end of the spectrum, the chemistry faculty (n = 20) had primarily teacher-centered views and experienced contextual factors that hindered the adoption of student-centered practices. Biology faculty (n = 25) fell between these two groups. Classroom observational data reflected these differences: The physics classrooms were significantly more student-centered than the chemistry classrooms. Conclusions: This study demonstrates that disciplinary differences exist in the contextual factors teaching conceptions that STEM faculty experience and hold, even among faculty within the same institution. Moreover, it shows that these differences are associated to the level of adoption of student-centered teaching practices. This work has thus identified the critical need to carefully characterize STEM faculty’s departmental environment and conceptions about teaching before engaging in instructional reform efforts, and to adapt reform activities to account for these factors. The results of this study also caution the over generalization of findings from a study focused on one type of STEM faculty in one environment to all STEM faculty in any environment

Differential stem cell contributions to thymocyte succession during development of Xenopus laevis.

Abstract The contribution of two embryonic stem cell compartments to the developing thymus in the amphibian Xenopus was examined throughout the larval, postmetamorphic, and adult periods. Hematopoietic chimeras were produced by transplanting either the ventral blood islands (VBI) or the dorsal stem cell compartment (DSC) from diploid donors onto triploid hosts. The DNA content of isolated nuclei harvested from the thymus and circulating E populations was analyzed using propidium iodide staining and flow cytometry. The DNA content of mitotic figures derived from PHA reactive splenocytes was analyzed using the Feulgen reaction and microdensitometry. These data suggested that both the VBI and DSC contribute to the thymocyte populations from the earliest developmental stages examined. Moreover, the contribution of both stem cell compartments was cyclic. However, the periods of these cycles were different. Both VBI- and DSC-derived cells entered the thymus 4 days postfertilization. VBI-derived thymocytes were at a minimum at 28 days postfertilization, reached a maximum at 35 days postfertilization and a second minimum at 42 days postfertilization. However, DSC-derived cells reached a maximum at 28 days, a minimum at 35 days, and a second maximum at 42 days. The PHA-reactive splenocyte population followed a similar temporal pattern. In contrast, the VBI-derived E population was at a maximum during early development and steadily declined throughout the larval period. DSC-derived E were undetectable during early development but steadily increased throughout the larval period. Both VBI- and DSC-derived hematopoietic cells persisted after metamorphosis and contributed to all populations examined in adult frogs. Because of temporal differences in the VBI and DSC contributions to the developing thymus, these data suggest heterogeneity within the thymocyte population associated with the embryonic origin of the colonizing stem cells.</jats:p