1,148 research outputs found
Everyman\u27s Climb
Hal and Verity represent two different philosophies of learning, one used by most of us. In today’s world, authentic teaching is indeed a heroic act, but may not be the most popular. This piece draws distinctions between these choices, each time we teach a course, each day we walk into the classroom, and even when working with an individual student; they are ever present
Analysis of Cellular Signaling Events by Flow Cytometry
12 pagesAll the cells are engaged on a cell communication by sending and receiving signals. Cells having the correct receptors on their surfaces will encode the plasma membrane signal recognition to intracellular signals corresponding to cellular signaling events. This process corresponds to a huge intracellular network of protein-protein or lipid-protein interactions. To avoid to be lost in this kind of maze, some general signaling pathways are most of the time present in many cell systems such as MAP kinases or PI-3 kinases pathways. These signaling pathways induce some protein phosphorylation events that can be identified by specific antibodies directed against these phosphosites (anti-phospho antibodies). Thus, these crossroads can be determined by using antibodies. A widely used method to identify these signaling events is the Western blotting or protein immunoblotting from cell extracts. However, several research groups are now developing new analytical techniques based also on the use of anti-phospho antibodies, but allowing them to detect signaling events at the single cell level. These experimental approaches are using the principles of the flow cytometry (FCM). Phosphoflow technology will provide rapid, quantitative and also multi-parameter analyses on single cells
The shortwave infrared bands response to stomatal conductance in Conference" Pear Trees (Pyrus communis L.)"
Published: 8 October 201
Limits on dust emission from z~5 LBGs and their local environments
We present 1.2mm MAMBO-2 observations of a field which is over-dense in Lyman
Break Galaxies (LBGs) at z~5. The field includes seven
spectroscopically-confirmed LBGs contained within a narrow (z=4.95+/-0.08)
redshift range and an eighth at z=5.2. We do not detect any individual source
to a limit of 1.6 mJy/beam (2*rms). When stacking the flux from the positions
of all eight galaxies, we obtain a limit to the average 1.2 mm flux of these
sources of 0.6mJy/beam. This limit is consistent with FIR imaging in other
fields which are over-dense in UV-bright galaxies at z~5. Independently and
combined, these limits constrain the FIR luminosity (8-1000 micron) to a
typical z~5 LBG of LFIR<~3x10^11 Lsun, implying a dust mass of Mdust<~10^8 Msun
(both assuming a grey body at 30K). This LFIR limit is an order of magnitude
fainter than the LFIR of lower redshift sub-mm sources (z~1-3). We see no
emission from any other sources within the field at the above level. While this
is not unexpected given millimetre source counts, the clustered LBGs trace
significantly over-dense large scale structure in the field at z = 4.95. The
lack of any such detection in either this or the previous work, implies that
massive, obscured star-forming galaxies may not always trace the same
structures as over-densities of LBGs, at least on the length scale probed here.
We briefly discuss the implications of these results for future observations
with ALMA.Comment: 10 pages, 6 figures, MNRAS Accepte
Deep, ultra-high-resolution radio imaging of submillimetre galaxies using Very Long Baseline Interferometry
We present continent-scale VLBI - obtained with the European VLBI Network
(EVN) at a wavelength of 18cm - of six distant, luminous submm-selected
galaxies (SMGs). Our images have a synthesized beam width of ~30 milliarcsec
FWHM - three orders of magnitude smaller in area than the highest resolution
VLA imaging at this wavelength - and are capable of separating radio emission
from ultra-compact radio cores (associated with active super-massive black
holes - SMBHs) from that due to starburst activity. Despite targeting compact
sources - as judged by earlier observations with the VLA and MERLIN - we
identify ultra-compact cores in only two of our targets. This suggests that the
radio emission from SMGs is produced primarily on larger scales than those
probed by the EVN, and therefore is generated by star formation rather than an
AGN - a result consistent with other methods used to identify the presence of
SMBHs in these systems.Comment: MNRAS, in pres
A continuous isotropic-nematic liquid crystalline transition of F-actin solutions
The phase transition from the isotropic (I) to nematic (N) liquid crystalline
suspension of F-actin of average length m or above was studied by local
measurements of optical birefringence and protein concentration. Both
parameters were detected to be continuous in the transition region, suggesting
that the I-N transition is higher than 1st order. This finding is consistent
with a recent theory by Lammert, Rokhsar & Toner (PRL, 1993, 70:1650),
predicting that the I-N transition may become continuous due to suppression of
disclinations. Indeed, few line defects occur in the aligned phase of F-actin.
Individual filaments in solutions of a few mg/ml F-actin undergo fast
translational diffusion along the filament axis, whereas both lateral and
rotational diffusions are suppressed.Comment: 4 pages with 4 figures. Submitted to Physical Review Letter
Does metformin improve vascular health in children with Type 1 diabetes? Protocol for a one year, double blind, randomised, placebo controlled trial
Background: Cardiovascular disease is the leading cause of mortality in Type 1 diabetes (T1D). Vascular dysfunction is an early and critical event in the development of cardiovascular disease. Children with T1D have vascular dysfunction therefore early interventions to improve vascular health are essential to reduce cardiovascular mortality in T1D. Metformin is an insulin sensitising agent which is known to improve vascular health outcomes in type 2 diabetes (T2D) and other individuals with insulin resistance. It has been used safely in children and adolescents with T2D for over 10 years. This study aims to assess the effect of metformin on vascular health in children with T1D. Methods/Design: This study is a 12 month, double blind, randomised, placebo controlled trial to determine the effect of metformin on vascular health in children (age 8–18) with T1D. The sample size is 76 with 38 children in the metformin group and 38 children in the placebo group. Vascular health and biochemical markers will be measured at baseline, 3, 6 and 12 months. Vascular function will be measured using flow mediated dilatation and glyceryl trinitrate mediated dilatation of the brachial artery and vascular structure will be measured with carotid and aortic intima media thickness, using standardised protocols. Discussion: This study will be the first to investigate the effect of metformin on vascular health in children with T1D. It will provide important information on a potential intervention to improve cardiovascular morbidity and mortality in this population at high risk from cardiovascular disease.Jemma Anderson, Alexia S Peña, Thomas Sullivan, Roger Gent, Bronwen D’Arcy, Timothy Olds, Brian Coppin and Jennifer Coupe
Entanglement, elasticity and viscous relaxation of actin solutions
We have investigated the viscosity and the plateau modulus of actin solutions
with a magnetically driven rotating disc rheometer. For entangled solutions we
observed a scaling of the plateau modulus versus concentration with a power of
7/5. The measured terminal relaxation time increases with a power 3/2 as a
function of polymer length. We interpret the entanglement transition and the
scaling of the plateau modulus in terms of the tube model for semiflexible
polymers.Comment: 5 pages, 4 figures, published versio
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