4,582 research outputs found
Nichtokulomotorische Augenbeteiligung bei Möbius-Sequenz
Zusammenfassung: Die Möbius-Sequenz betrifft nicht nur die Okulomotorik, sondern auch die Augen selbst. Das Sehen der Patienten kann durch das Syndrom erheblich beeintrĂ€chtigt sein. Daher bedarf es regelmĂ€Ăiger augenĂ€rztlicher Kontrolle
Diagnose und Therapie okulomotorischer Defizite bei Patienten mit Möbius-Sequenz
Zusammenfassung: Der Artikel gibt einen Ăberblick ĂŒber das Spektrum möglicher MotilitĂ€tseinschrĂ€nkungen und Stellungsanomalien der Augen bei Patienten mit Möbius-Sequenz. Die augenmuskelchirurgischen Behandlungsoptionen werden diskutiert und es wird ein operatives Stufenschema vorgestell
Complementary Observables for the Determination of |Vub| in Inclusive Semileptonic B Decays
The determination of |Vub| from inclusive semileptonic B decays is limited by
uncertainties in modelling the decay distributions in b->ulnu transitions. The
largest uncertainties arise from the limited knowledge of the appropriate b
quark mass and Fermi momentum to use in the parameterization of the shape
function. This paper presents a new method in which these shape function
parameters are constrained by the same data used to measure |Vub|. The method
requires measurements of the momenta of both the charged lepton and the
neutrino in semileptonic B decays. From these quantities two complementary
observables can be constructed, one for discriminating between b->ulnu
transitions and background and the other for constraining the shape function.
Using this technique the uncertainties in |Vub| from the shape function may be
significantly reduced.Comment: 8 pages, 3 figure
Barrett's esophagus: Origin, development and options for therapeutic intervention
Barrettâs esophagus (BE) consists of a metaplasia in which the normal squamous
cells lining the esophagus are replaced by a mixture of gastric and intestinal lining
cells. The intestinal-type lining cells are often referred to as specialized columnar
cells and include e.g. goblet cells. For a number of years, some scientists thought
that there were two types of BE; one in which the normal lining was replaced with
gastric type cells only, and the second in which intestinal cells were present. Presently,
intestinal metaplasia is required for the diagnosis of BE because intestinal
metaplasia is the only type of esophageal columnar epithelium that clearly predisposes
to malignancy.
BE is a complication of chronic gastroesophageal reflux disease (GERD), primarily
in white men. GERD is a disease in which there is reflux of acidic fluid from the
stomach and bile contents from the duodenum into the esophagus. It most commonly
causes heartburn, but many patients do not have any symptoms
Automation of cell culture assays using a 3D-printed servomotor-controlled microfluidic valve system
Microfluidic valve systems show great potential to automate mixing, dilution, and time-resolved reagent supply within biochemical assays and novel on-chip cell culture systems. However, most of these systems require a complex and cost-intensive fabrication in clean room facilities, and the valve control element itself also requires vacuum or pressure sources (including external valves, tubing, ports and pneumatic control channels). Addressing these bottlenecks, the herein presented biocompatible and heat steam sterilizable microfluidic valve system was fabricated via high-resolution 3D printing in a one-step process - including inlets, micromixer, microvalves, and outlets. The 3D-printed valve membrane is deflected via miniature on-chip servomotors that are controlled using a Raspberry Pi and a customized Python script (resulting in a device that is comparatively low-cost, portable, and fully automated). While a high mixing accuracy and long-term robustness is established, as described herein the system is further applied in a proof-of-concept assay for automated IC50 determination of camptothecin with mouse fibroblasts (L929) monitored by a live-cell-imaging system. Measurements of cell growth and IC50 values revealed no difference in performance between the microfluidic valve system and traditional pipetting. This novel design and the accompanying automatization scripts provide the scientific community with direct access to customizable full-time reagent control of 2D cell culture, or even novel organ-on-a-chip systems
Trophic ecology of the invasive argentine ant: spatio-temporal variation in resource assimilation and isotopic enrichment
Studies of food webs often employ stable isotopic approaches to infer trophic position and interaction strength without consideration of spatio-temporal variation in resource assimilation by constituent species. Using results from laboratory diet manipulations and monthly sampling of field populations, we illustrate how nitrogen isotopes may be used to quantify spatio-temporal variation in resource assimilation in ants. First, we determined nitrogen enrichment using a controlled laboratory experiment with the invasive Argentine ant (Linepithema humile). After 12 weeks, worker ÎŽ15N values from colonies fed an animal-based diet had ÎŽ15N values that were 5.51% greater compared to colonies fed a plant-based diet. The shift in ÎŽ15N values in response to the experimental diet occurred within 10 weeks. We next reared Argentine ant colonies with or without access to honeydew-producing aphids and found that after 8 weeks workers from colonies without access to aphids had ÎŽ15N values that were 6.31% larger compared to colonies with access to honeydew. Second, we sampled field populations over a 1-year period to quantify spatio-temporal variability in isotopic ratios of L. humile and those of a common native ant (Solenopsis xyloni). Samples from free-living colonies revealed that fluctuations in ÎŽ15N were 1.6â2.4â° for L. humile and 1.8â2.9â° for S. xyloni. Variation was also detected among L. humile castes: time averaged means of ÎŽ15N varied from 1.2 to 2.5â° depending on the site, with ÎŽ15N values for queens â„ workers > brood. The estimated trophic positions of L. humile and S. xyloni were similar within a site; however, trophic position for each species differed significantly at larger spatial scales. While stable isotopes are clearly useful for examining the trophic ecology of arthropod communities, our results suggest that caution is warranted when making ecological interpretations when stable isotope collections come from single time periods or life stages
Relative luminosity measurement of the LHC with the ATLAS forward calorimeter
In this paper it is shown that a measurement of the relative luminosity
changes at the LHC may be obtained by analysing the currents drawn from the
high voltage power supplies of the electromagnetic section of the forward
calorimeter of the ATLAS detector. The method was verified with a reproduction
of a small section of the ATLAS forward calorimeter using proton beams of known
beam energies and variable intensities at the U-70 accelerator at IHEP in
Protvino, Russia. The experimental setup and the data taking during a test beam
run in April 2008 are described in detail. A comparison of the measured high
voltage currents with reference measurements from beam intensity monitors shows
a linear dependence on the beam intensity. The non-linearities are measured to
be less than 0.5 % combining statistical and systematic uncertainties.Comment: 16 page
Inversion of provenance data and sediment load into spatially varying erosion rates
Sediment fingerprinting methods aim to determine the relative contribution of different source areas in detrital sediments based on natural properties â fingerprints â of the source areas. Here, we use U/ThâPb age signatures as fingerprints, assuming that the age signal is not altered during erosionâtransportationâdeposition events, and given that recent technological advances enable precise dating of large amounts of grains. We introduce a formal inversion method that allows to disentangle the amalgamation of source contributions in detrital zircon data and enables to convert this information into an erosion rate map starting from the spatial distribution of zircon age signatures. Relying on the leastâsquares method and using prior and covariance information to deal with nonâuniqueness, we show, using synthetic and natural examples, that we are able to retrieve erosion rate patterns of a catchment when the age distribution and zircon fertility for each source area are well known. Moreover, we show that not only zircon age fingerprints but also other tracers such as mineral content can be used. Furthermore, we found that adding data from samples taken at the outlet of tributaries improves the estimation of erosion rate patterns. We conclude that the least squares inverse model applied to detrital data has great potential for investigating erosion rates
Lithospheric deformation in the Canadian Appalachians : evidence from shear wave splitting
This work was funded by Leverhulme Trust research project grant RPG-2013-332. Imperial College Maritimes network stations were provided through Natural Environment Research Council (NERC) Geophysical Equipment Facility loan 986. Logistical field support was provided by D. Heffler, D. Simpson, and residents of Nova Scotia and New Brunswick. Data for Portable Observatories for Lithospheric Analysis and Research Investigating Seismicity (POLARIS) and Canadian National Seismograph Network stations were downloaded from the Canadian National Data Centre. POLARIS stations were funded by the Canadian Foundation for Innovation, Natural Resources Canada and Industry Canada. FD is supported by Natural Sciences and Engineering Research Council of Canada through the Discovery Grants and Canada Research Chair programmes. AB is funded by the NERC Doctoral Training Partnership: Science and Solutions for a Changing Planet. We thank Thomas Plenefisch and an anonymous reviewer for their comments on this manuscript.Peer reviewedPublisher PD
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