858 research outputs found
PCN90 Cost-Effectiveness of a Biopsy-Based 8-Protein Prognostic Assay to Optimize Treatment Decisions In Gleason 3+3 And 3+4 Prostate Cancer
Lateral vibration effects in atomic-scale friction
The influence of lateral vibrations on the stick-slip motion of a nanotip elastically pulled on a flat crystal surface is studied by atomic force microscopy measurements on a NaCl(001) surface in ultra-high vacuum. The slippage of the nanotip across the crystal lattice is anticipated at increasing driving amplitude, similarly to what is observed in presence of normal vibrations. This lowers the average friction force, as explained by the Prandtl-Tomlinson model with lateral vibrations superimposed at finite temperature. Nevertheless, the peak values of the lateral force, and the total energy losses, are expected to increase with the excitation amplitude, which may limit the practical relevance of this effect
3D-Spectroscopy of extragalactic planetary nebulae as diagnostic probes for galaxy evolution
In addition to study extragalactic stellar populations in their integrated
light, the detailed analysis of individual resolved objects has become
feasible, mainly for luminous giant stars and for extragalactic planetary
nebulae (XPNe) in nearby galaxies. A recently started project at the
Astrophysical Institute Potsdam (AIP), called ``XPN--Physics'', aims to verify
if XPNe are useful probes to measure the chemical abundances of their parent
stellar population. The project involves theoretical and observational work
packages.Comment: 3 pages, 2 figures, to appear in Sciences Perspectives for 3D
Spectroscopy. ESO Astrophysics Symposia. Edited by M.Kissler-Patig, M.M. Roth
and J.R. Wals
Discovery of new GPCR ligands to illuminate new biology
Although a plurality of drugs target G-protein-coupled receptors (GPCRs), most have emerged from classical medicinal chemistry and pharmacology programs and resemble one another structurally and functionally. Though effective, these drugs are often promiscuous. With the realization that GPCRs signal via multiple pathways, and with the emergence of crystal structures for this family of proteins, there is an opportunity to target GPCRs with new chemotypes and confer new signaling modalities. We consider structure-based and physical screening methods that have led to the discovery of new reagents, focusing particularly on the former. We illustrate their use against previously untargeted or orphan GPCRs, against allosteric sites, and against classical orthosteric sites that selectively activate one downstream pathway over others. The ligands that emerge are often chemically novel, which can lead to new biological effects. © 2017 Nature America, Inc., part of Springer Nature. All rights
Campylobacter infection and household factors are associated with childhood growth in urban Bangladesh : an analysis of the MAL-ED study
The dual burden of enteric infection and childhood malnutrition continues to be a global health concern and a leading cause of morbidity and death among children. Campylobacter infection, in particular, is highly prevalent in low- and middle-income countries, including Bangladesh. We examined longitudinal data to evaluate the trajectories of change in child growth, and to identify associations with Campylobacter infection and household factors. The study analyzed data from 265 children participating in the MAL-ED Study in Mirpur, Bangladesh. We applied latent growth curve modelling to evaluate the trajectories of change in children’s height, as measured by length-for-age z-score (LAZ), from age 0–24 months. Asymptomatic and symptomatic Campylobacter infections were included as 3- and 6-month lagged time-varying covariates, while household risk factors were included as time-invariant covariates. Maternal height and birth order were positively associated with LAZ at birth. An inverse association was found between increasing age and LAZ. Campylobacter infection prevalence increased with age, with over 70% of children 18–24 months of age testing positive for infection. In the final model, Campylobacter infection in the preceding 3-month interval was negatively associated with LAZ at 12, 15, and 18 months of age; similarly, infection in the preceding 6-month interval was negatively associated with LAZ at 15, 18, and 21 months of age. Duration of antibiotic use and access to treated drinking water were negatively associated with Campylobacter infection, with the strength of the latter effect increasing with children’s age. Campylobacter infection had a significant negative effect on child’s growth and this effect was most powerful between 12 and 21 months. The treatment of drinking water and increased antibiotic use have a positive indirect effect on linear child growth trajectory, acting via their association with Campylobacter infection
Laser spectroscopy of hyperfine structure in highly-charged ions: a test of QED at high fields
An overview is presented of laser spectroscopy experiments with cold,
trapped, highly-charged ions, which will be performed at the HITRAP facility at
GSI in Darmstadt (Germany). These high-resolution measurements of ground state
hyperfine splittings will be three orders of magnitude more precise than
previous measurements. Moreover, from a comparison of measurements of the
hyperfine splittings in hydrogen- and lithium-like ions of the same isotope,
QED effects at high electromagnetic fields can be determined within a few
percent. Several candidate ions suited for these laser spectroscopy studies are
presented.Comment: 5 pages, 1 figure, 1 table. accepted for Canadian Journal of Physics
(2006
Neuromuscular synaptic function in mice lacking major subsets of gangliosides
Gangliosides are a family of sialylated glycosphingolipids enriched in the outer leaflet of neuronal membranes, in particular at synapses. Therefore, they have been hypothesized to play a functional role in synaptic transmission. We have measured in detail the electrophysiological parameters of synaptic transmission at the neuromuscular junction (NMJ) ex vivo of a GD3-synthase knockout mouse, expressing only the O- and a-series gangliosides, as well as of a GM2/GD2-synthase*GD3-synthase double-knockout (dKO) mouse, lacking all gangliosides except GM3. No major synaptic deficits were found in either null-mutant. However, some extra degree of rundown of acetylcholine release at high intensity use was present at the dKO NMJ and a temperature-specific increase in acetylcholine release at 35 °C was observed in GD3-synthase knockout NMJs, compared with wild-type. These results indicate that synaptic transmission at the NMJ is not crucially dependent on the particular presence of most ganglioside family members and remains largely intact in the sole presence of GM3 ganglioside. Rather, presynaptic gangliosides appear to play a modulating role in temperature- and use-dependent fine-tuning of transmitter output
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Prone to Supine CT Colonography Registration Using a Landmark and Intensity Composite Method
Matching corresponding location between prone and supine acquisitions for CT colonography (CTC) is essential to verify the existence of a polyp, which can be a difficult task due to the considerable deformations that will often occur to the colon during repositioning of the patient. This can induce error and increase interpretation time. We propose a novel method to automatically establish correspondence between the two acquisitions. A first step segments a set of haustral folds in each view and determines correspondence via a labelling process using a Markov Random Field (MRF) model. We show how the landmark correspondences can be used to non-rigidly transform a 2D source image derived from a conformal mapping process on the 3D endoluminal surface mesh to achieve full surface correspondence between prone and supine views. This can be used to initialise an intensity-based non-rigid B-spline registration method which further increases the accuracy. We demonstrate a statistically significant improvement over the intensity based non-rigid B-spline registration by using the composite method
Local adaptations and phenotypic plasticity may render gypsy moth and nun moth future pests in northern European boreal forests
Phenotypic plasticity and local adaptations are important factors in predicting range expansions and shifts of pest insects in a changing climate. We reared two lepidopteran forest pests, Lymantria monacha (Linnaeus) and Lymantria dispar (Linnaeus), at three climatically different field sites from central Germany to northern Finland to investigate differences among populations in plasticity in the timing of pupation and adult emergence (measured as cumulative temperature sums, degree-days >5 °C), pupal mass, and duration of the pupal period. We also compared the phenologies of continental and boreal L. monacha populations feeding on Scots pine (Pinus sylvestris L.) to reveal possible local adaptations. Lymantria dispar was reared on different host plants, Quercus robur L., Betula pendula Roth, and Betula pubescens ssp. czerepanovii (Orl.) Hämet-Ahti, to evaluate the possibilities of a range expansion northwards. There was stronger indication of adaptive phenotypic plasticity, which enables species to cope with changing environmental conditions, in continental L. dispar and boreal L. monacha populations than in the continental L. monacha population. Differences between boreal and continental L. monacha populations may denote adaptation to local conditions. All three host plants used for L. dispar proved suitable for the species, revealing that host plant availability would not limit its range expansion in northern Europe.</p
Mixtures of Bosonic and Fermionic Atoms in Optical Lattices
We discuss the theory of mixtures of Bosonic and Fermionic atoms in periodic
potentials at zero temperature. We derive a general Bose--Fermi Hubbard
Hamiltonian in a one--dimensional optical lattice with a superimposed harmonic
trapping potential. We study the conditions for linear stability of the mixture
and derive a mean field criterion for the onset of a Bosonic superfluid
transition. We investigate the ground state properties of the mixture in the
Gutzwiller formulation of mean field theory, and present numerical studies of
finite systems. The Bosonic and Fermionic density distributions and the onset
of quantum phase transitions to demixing and to a Bosonic Mott--insulator are
studied as a function of the lattice potential strength. The existence is
predicted of a disordered phase for mixtures loaded in very deep lattices. Such
a disordered phase possessing many degenerate or quasi--degenerate ground
states is related to a breaking of the mirror symmetry in the lattice.Comment: 11 pages, 8 figures; added discussions; conclusions and references
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