The Mechanism of Sertoli-Germ Cell Interaction a

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73914/1/j.1749-6632.1987.tb25056.x.pd

Short-term emission line and continuum variations in Mrk110

We present results of a variability campaign of Mrk110 performed with the 9.2-m Hobby-Eberly Telescope (HET) at McDonald Observatory. The high S/N spectra cover most of the optical range. They were taken from 1999 November through 2000 May. The average interval between the observations was 7.3 days and the median interval was only 3.0 days. Mrk110 is a narrow-line Seyfert 1 galaxy. During our campaign the continuum flux was in a historically low stage. Considering the delays of the emission lines with respect to the continuum variations we could verify an ionization stratification of the BLR. We derived virial masses of the central black hole from the radial distances of the different emission lines and from their widths. The calculated central masses agree within 20%. Furthermore, we identified optical HeI singlet emission lines emitted in the broad-line region. The observed line fluxes agree with theoretical predictions. We show that a broad wing on the red side of the [OIII]5007 line is caused by the HeI singlet line at 5016A.Comment: 11 pages, 16 figures, A&A Latex. Accepted for publication in A&A Main Journa

Student perceptions of iPads as mobile learning devices for fieldwork

This paper reports findings from six field courses about student’s perceptions of iPads as mobile learning devices for fieldwork. Data were collected through surveys and focus groups. The key findings suggest that the multi-tool nature of the iPads and their portability were the main strengths. Students had some concerns over the safety of the iPads in adverse weather and rugged environments, though most of these concerns were eliminated after using the devices with protective cases. Reduced connectivity was found to be one of the main challenges for mobile learning. Finally, students and practitioners views of why they used the mobile devices for fieldwork did not align

Breed type influences hypothalamic-pituitary-adrenal axis activity and responsiveness to exogenous bovine corticotropin-releasing hormone (hCRR) in beef steers

Last updated: 6/12/200

Genetic Determinants of UV-Susceptibility in Non-Melanoma Skin Cancer

A milieu of cytokines and signaling molecules are involved in the induction of UV-induced immune suppression and thus the etiology of non-melanoma skin cancer (NMSC). Targeting the UV-induced immunosuppression pathway, and using a large population based study of NMSC, we have investigated the risk associated with functional variants in 10 genes (IL10, IL4, IL4R, TNF, TNFR2, HTR2A, HRH2, IL12B, PTGS2, and HAL). The most prominent single genetic effect was observed for IL10. There was increasing risk for both basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) with increasing number of variant IL10 haplotypes (BCC: ptrend = 0.0048; SCC: ptrend = 0.031). Having two IL10 GC haplotypes was associated with increased odds ratios of BCC and SCC (ORBCC = 1.5, 95% CI 1.1–1.9; ORSCC = 1.4, 95% CI 1.0–1.9), and these associations were largely confined to women (ORBCC = 2.2, 95% CI 1.4–3.4; SCC: ORSCC = 1.8, 95% CI 1.1–3.0). To examine how combinations of these variants contribute to risk of BCC and SCC, we used multifactor dimensionality reduction (MDR) and classification and regression trees (CART). Results from both of these methods found that in men, a combination of skin type, burns, IL10, IL4R, and possibly TNFR2 were important in both BCC and SCC. In women, skin type, burns, and IL10 were the most critical risk factors in SCC, with risk of BCC involving these same factors plus genetic variants in HTR2A, IL12B and IL4R. These data suggest differential genetic susceptibility to UV-induced immune suppression and skin cancer risk by gender

emiT: an apparatus to test time reversal invariance in polarized neutron decay

We describe an apparatus used to measure the triple-correlation term (\D \hat{\sigma}_n\cdot p_e\times p_\nu) in the beta-decay of polarized neutrons. The \D-coefficient is sensitive to possible violations of time reversal invariance. The detector has an octagonal symmetry that optimizes electron-proton coincidence rates and reduces systematic effects. A beam of longitudinally polarized cold neutrons passes through the detector chamber, where a small fraction beta-decay. The final-state protons are accelerated and focused onto arrays of cooled semiconductor diodes, while the coincident electrons are detected using panels of plastic scintillator. Details regarding the design and performance of the proton detectors, beta detectors and the electronics used in the data collection system are presented. The neutron beam characteristics, the spin-transport magnetic fields, and polarization measurements are also described.Comment: 15 pages, 13 figure

Targeted Enhancer Activation by a Subunit of the Integrator Complex

The control of cell fate is an epigenetic process initiated by transcription factors (TFs) that recognize DNA motifs and recruit activator complexes and transcriptional machineries to chromatin. Lineage specificity is thought to be provided solely by TF-motif pairing, while the recruited activators are passive. Here, we show that INTS13, a subunit of the Integrator complex, operates as monocytic/macrophagic differentiation factor. Integrator is a general activator of transcription at coding genes and is required for eRNA maturation. Here, we show that INTS13 functions as an independent sub-module and targets enhancers through Early Growth Response (EGR1/2) TFs and their co-factor NAB2. INTS13 binds poised monocytic enhancers eliciting chromatin looping and activation. Independent depletion of INTS13, EGR1, or NAB2 impairs monocytic differentiation of cell lines and primary human progenitors. Our data demonstrate that Integrator is not functionally homogeneous and has TF-specific regulatory potential, revealing a new enhancer regulatory axis that controls myeloid differentiation. Barbieri et al. demonstrate that a subunit of the Integrator complex, INTS13, is required for monocytic commitment of myeloid progenitors. INTS13 is a modular component of Integrator recruited to poised enhancers via the EGR1 transcription factor and its co-factor NAB2. The INTS13/EGR1/NAB2 axis is essential to elicit enhancer-mediated gene activation

Computer simulations of heterologous immunity: Highlights of an interdisciplinary cooperation

The relationship between biological research and mathematical modeling is complex, critical, and vital. In this review, we summarize the results of the collaboration between two laboratories, exploring the interaction between mathematical modeling and wet-lab immunology. During this collaboration several aspects of the immune defence against viral infections were investigated, focusing primarily on the subject of heterologous immunity. In this manuscript, we emphasize the topics where computational simulations were applied in conjunction with experiments, such as immune attrition, the growing and shrinking of cross-reactive T cell repertoires following repeated infections, the short and long-term effects of cross-reactive immunological memory, and the factors influencing the appearance of new clonal specificities. For each topic, we describe how the mathematical model used was adapted to answer specific biological questions, and we discuss the hypotheses that were generated by simulations. Finally, we propose rules for testing hypotheses that emerge from model experimentation in the wet lab, and vice-versa

Completion of fit notes by GPs: a mixed methods study

Aims: The aim of this study was to investigate the completion of fit notes by UK general practitioners (GPs). A series of actual fit notes issued to employed patients were examined, and their GPs’ reflections and experiences of fit note completion explored. Methods: A mixed-methods design was used. Data were collected from copies of 94 fit notes issued to employed patients by 11 GPs, and from 86 questionnaires completed by these GPs reflecting on the fit notes they had issued. Face-to-face interviews were then conducted with each GP. Results: Fit note completion is not meeting expectations for a number of reasons. These include the following: limited knowledge and awareness of the guidance in fit note completion; problems with the fit note format; lack of mandatory training in completing fit notes; lack of incentive to change practice; incomplete implementation of the electronic fit note; GPs’ lack of confidence in, and doubts about the appropriateness of performing this role. Conclusion: If UK GPs are to continue their contractual responsibility for completing fit notes, further consideration of their education and training needs is urgently required. Weaknesses in the design and format of the fit note and the availability of the electronic version also need to be addressed