Cartilage on the Move: Cartilage Lineage Tracing During Tadpole Metamorphosis

The reorganization of cranial cartilages during tadpole metamorphosis is a set of complex processes. The fates of larval cartilage-forming cells (chondrocytes) and sources of adult chondrocytes are largely unknown. Individual larval cranial cartilages may either degenerate or remodel, while many adult cartilages appear to form de novo during metamorphosis. Determining the extent to which adult chondrocytes/cartilages are derived from larval chondrocytes during metamorphosis requires new techniques in chondrocyte lineage tracing. We have developed two transgenic systems to label cartilage cells throughout the body with fluorescent proteins. One system strongly labels early tadpole cartilages only. The other system inducibly labels forming cartilages at any developmental stage. We examined cartilages of the skull (viscero- and neurocranium), and identified larval cartilages that either resorb or remodel into adult cartilages. Our data show that the adult otic capsules, tecti anterius and posterius, hyale, and portions of Meckel\u27s cartilage are derived from larval chondrocytes. Our data also suggest that most adult cartilages form de novo, though we cannot rule out the potential for extreme larval chondrocyte proliferation or de- and re-differentiation, which could dilute our fluorescent protein signal. The transgenic lineage tracing strategies developed here are the first examples of inducible, skeleton-specific, lineage tracing in Xenopus

Warm HCN, C2H2, and CO in the disk of GV Tau

We present the first high-resolution, ground-based observations of HCN and C2H2 toward the T Tauri binary star system GV Tau. We detected strong absorption due to HCN nu_3 and weak C2H2 (nu_3 and nu_2 + (nu_4 + nu_5)^0_+) absorption toward the primary (GV Tau S) but not the infrared companion. We also report CO column densities and rotational temperatures, and present abundances relative to CO of HCN/CO ~0.6% and C2H2/CO ~1.2% and an upper limit for CH4/CO < 0.37% toward GV Tau S. Neither HCN nor C2H2 were detected toward the infrared companion and results suggest that abundances may differ between the two sources.Comment: 23 pages, 6 figures, accepted by Ap

An examination of health inequities among college students by sexual orientation identity and sex

Background. Lesbian, gay, and bisexual (LGB) college students may have an increased number of health inequities compared to their heterosexual counterparts. However, to date, no research has provided a comprehensive examination of health-related factors by sexual orientation identity and sex among a national sample of college students. Thus, the purpose of this study was to examine physical, sexual, interpersonal relations/safety, and mental health inequities by sexual orientation identity and sex among a national sample of college students. Design and methods. Participants (n=39,767) completed the National College Health Assessment II during the fall 2008/spring 2009 academic year. Hierarchical binary logistic regression analyses were used to examine health inequities by sexual orientation identity and sex. Results. LGB students compared to heterosexual students, experienced multiple health inequities including higher rates of being verbally threatened and lower rates of physical activity and condom use. Conclusions. An understanding of health inequities experienced by LGB college students is critical as during these years of transition, students engage in protective (e.g., physical activity) and risky (e.g., lack of condom use) health behaviours, establishing habits that could last a lifetime. Future research should be used to design and implement targeted public health strategies and policies to reduce health inequities and improve health-related quality of life among LGB college students

Survey of Ices toward Massive Young Stellar Objects: I. OCS, CO, OCN−^-, and CH3_3OH

An important tracer of the origin and evolution of cometary ices is the comparison with ices found in dense clouds and towards Young Stellar Objects (YSOs). We present a survey of ices in the 2-5 micron spectra of 23 massive YSOs, taken with the NASA InfraRed Telescope Facility SpeX spectrometer. The 4.90 micron absorption band of OCS ice is detected in 20 sight-lines, more than five times the previously known detections. The absorption profile shows little variation and is consistent with OCS being embedded in CH3OH-rich ices, or proton-irradiated H$_2$S or SO$_2$-containing ices. The OCS column densities correlate well with those of CH$_3$OH and OCN$^-$, but not with H$_2$O and apolar CO ice. This association of OCS with CH$_3$OH and OCN$^-$ firmly establishes their formation location deep inside dense clouds or protostellar envelopes. The median composition of this ice phase towards massive YSOs, as a percentage of H$_2$O, is CO:CH$_3$OH:OCN$^-$:OCS=24:20:1.53:0.15. CS, due to its low abundance, is likely not the main precursor to OCS. Sulfurization of CO is likely needed, although the source of this sulfur is not well constrained. Compared to massive YSOs, low mass YSOs and dense clouds have similar CO and CH$_3$OH ice abundances, but less OCN$^-$ and more apolar CO, while OCS awaits detection. Comets tend to be under-abundant in carbon-bearing species, but this does not appear to be the case for OCS, perhaps signalling OCS production in protoplanetary disks.Comment: 35 pages, 18 figures. Published ApJ 941, 32. Updated arXiv title and publication informatio

THE ROLE OF THE NMDA RECEPTOR AND REVERSE SODIUM CALCIUM EXCHANGER IN CALCIUM DYSREGULATION IN GLUTAMATE-EXPOSED NEURONS

Indiana University-Purdue University Indianapolis (IUPUI)Introduction: During glutamate excitotoxicity, overstimulation of glutamate receptors leads to sustained elevation in cytosolic Ca2+ ([Ca2+]c), or delayed Ca2+ dysregulation (DCD), which is causally linked to cell death. There are two major hypothetical mechanisms for DCD: the continuous activation of N-methyl-D-aspartate-subtype of the ionotropic glutamate receptors (NMDAR) and the reversal of the plasmalemmal Na+/Ca2+ exchanger. However, the contribution of each of these mechanisms in DCD is not completely established. Major results: Neurons exposed to excitotoxic glutamate produced DCD, an increase in cytosolic Na+ ([Na+]c), and plasma membrane depolarization. MK801 and memantine, noncompetitive NMDAR inhibitors, added after glutamate, completely prevented DCD; however AP-5, a competitive NMDAR inhibitor, failed to do so. The NMDAR inhibitors had no effect on lowering elevated [Na+]c or on restoring plasma membrane potential, which are conditions suggesting NCXrev could be involved. In experiments inducing NCXrev, MK801 and memantine completely inhibited Ca2+ dysregulation after glutamate while AP-5 did not. Inhibition of NCXrev, either with KB-R7943 or by preventing the increase in [Na+]c, failed to avert DCD. However, NCXrev inhibition combined with NMDAR blocked by AP-5 completely prevented DCD. Overall, these data suggested that both NMDAR and NCXrev are essential for glutamate-induced DCD, and inhibition of only one mechanism is insufficient to prevent collapse of calcium homeostasis. Based on the data above, we investigated a NMDA receptor antagonist currently in clinical trials for reducing the effects of glutamate excitotoxicity, ifenprodil. Ifenprodil is an activity-dependent, NMDAR inhibitor selective for the NR2B subunit. We found that ifenprodil not only inhibited the NR2B-specific NMDAR, but also inhibited NCXrev. If ifenprodil is combined with PEAQX, a NMDAR inhibitor selective for the NR2A subunit, low concentrations of both inhibitors completely prevent DCD. Conclusion: The inhibition of a single Ca2+ influx mechanism is insufficient in preventing DCD, which requires simultaneous inhibition of both the NMDAR and NCXrev. These findings are critical for the correct interpretation of the experimental results obtained with these inhibitors and for better understanding of their neuroprotective actions

Erratum: Warm HCN, C2H2, and CO in the Disk of GV Tau\u27\u27

This is an Erratum for the article 2007 ApJ 660 157

Embarking as Captain of the Ship for the Curriculum Committee

This commentary examines the curriculum chair’s responsibilities and discusses considerations when assuming this role, using a captain of the ship metaphor. From knowing the crew to managing a diverse set of responsibilities, the path to becoming an effective chair is challenging and each captain’s stripe must be earned. Advice is provided to assist with understanding the curriculum and governance processes, as well as the chair’s various roles and professional development. The need for both leadership and management is also emphasized

Patient and public involvement in care home research: Reflections on the how and why of involving patient and public involvement partners in qualitative data analysis and interpretation

Background There is limited evidence for the impact of involving patients and the public (PPI) in health research. Descriptions of the PPI process are seldom included in publications, particularly data analysis, yet an understanding of processes and impacts of PPI is essential if its contribution to research is to be evaluated. Objective To describe the ‘how’ of PPI in qualitative data analysis and critically reflect on potential impact. Methods We focus on the development and critical reflection of our step-by-step approach to collaborative qualitative data analysis (through a series of analysis workshops) in a specific care home study, and our long-term engagement model with patients and the public (termed PPI partners). Results An open access PPI group, with multiple events over time, sustained broad interest in care home research. Recordings of interview clips, role-play of interview excerpts and written theme summaries were used in workshops to facilitate PPI partner engagement with data analysis in a specific study. PPI resulted in changes to data interpretation and was perceived to make the research process accessible. We reflect on the challenge of judging the benefits of PPI and presenting PPI in research publications for critical commentary. Conclusions Patient and public involvement partners who are actively engaged with data analysis can positively influence research studies. However, guidance for researchers is needed on approaches to PPI, including appropriate levels and methods for evaluation. Without more systematic approaches, we argue that it is impossible to know whether PPI represents good use of resources and is generating a real impact

Panchromatic Imaging of a Transitional Disk: The Disk of GM Aur in Optical and FUV Scattered Light

We have imaged GM Aur with HST, detected its disk in scattered light at 1400A and 1650A, and compared these with observations at 3300A, 5550A, 1.1 microns, and 1.6 microns. The scattered light increases at shorter wavelengths. The radial surface brightness profile at 3300A shows no evidence of the 24AU radius cavity that has been previously observed in sub-mm observations. Comparison with dust grain opacity models indicates the surface of the entire disk is populated with sub-micron grains. We have compiled an SED from 0.1 microns to 1 mm, and used it to constrain a model of the star+disk system that includes the sub-mm cavity using the Monte Carlo Radiative Transfer code by Barbara Whitney. The best-fit model image indicates that the cavity should be detectable in the F330W bandpass if the cavity has been cleared of both large and small dust grains, but we do not detect it. The lack of an observed cavity can be explained by the presence of sub-microns grains interior to the sub-mm cavity wall. We suggest one explanation for this which could be due to a planet of mass <9 Jupiter masses interior to 24 AU. A unique cylindrical structure is detected in the FUV data from the Advanced Camera for Surveys/Solar Blind Channel. It is aligned along the system semi-minor axis, but does not resemble an accretion-driven jet. The structure is limb-brightened and extends 190 +/- 35 AU above the disk midplane. The inner radius of the limb-brightening is 40 +/- 10 AU, just beyond the sub-millimeter cavity wall.Comment: 40 pages, 11 figures, 4 tables, accepted to Ap

Dietary interventions for maintaining cognitive function in cognitively healthy people in mid life

This is the protocol for a review and there is no abstract. The objectives are as follows: In this review we will set out to evaluate the effects of dietary interventions for maintaining cognitive function in cognitively healthy people in mid-life and preventing cognitive decline in late life