761 research outputs found
Dynamic contour tonometry versus Goldmann applanation tonometry: challenging the gold standard
The accurate measurement of intraocular pressure (IOP) is fundamental to almost any ophthalmic examination. Dynamic contour tonometry (DCT) was introduced 5 years ago as an entirely novel contact tonometry principle designed to measure IOP largely independently of corneal properties. Since then, many studies have compared the performance of this tonometer to the Goldmann applanation tonometer (GAT) and other tonometers in healthy eyes, as well as eyes with glaucoma or corneal diseases, and after corneal surgery. There is now strong evidence that DCT measures IOP very accurately, with very low inter- and intraobserver variability. This article summarizes the findings of these studies and analyzes the role of DCT in challenging GAT as the gold-standard tonometer for IOP measurements
A Brief History of Web Crawlers
Web crawlers visit internet applications, collect data, and learn about new
web pages from visited pages. Web crawlers have a long and interesting history.
Early web crawlers collected statistics about the web. In addition to
collecting statistics about the web and indexing the applications for search
engines, modern crawlers can be used to perform accessibility and vulnerability
checks on the application. Quick expansion of the web, and the complexity added
to web applications have made the process of crawling a very challenging one.
Throughout the history of web crawling many researchers and industrial groups
addressed different issues and challenges that web crawlers face. Different
solutions have been proposed to reduce the time and cost of crawling.
Performing an exhaustive crawl is a challenging question. Additionally
capturing the model of a modern web application and extracting data from it
automatically is another open question. What follows is a brief history of
different technique and algorithms used from the early days of crawling up to
the recent days. We introduce criteria to evaluate the relative performance of
web crawlers. Based on these criteria we plot the evolution of web crawlers and
compare their performanc
Gold(III) complexes for antitumor applications: An overview
Gold(III) complexes have emerged as a versatile and effective class of metal‐based anticancer agents. The development of various types of ligands capable of stabilizing the AuIII cation and preventing its reduction under physiological conditions, such as chelating nitrogen‐donors, dithiocarbamates and C^N cyclometalled ligands, has opened the way for the exploration of their potential intracellular targets and action mechanisms. At the same time, the bioconjugation of AuIII complexes has emerged as a promising strategy for improving the selectivity of this class of compounds for cancer cells over healthy tissues, and recent developments have shown that combining gold complexes with molecular structures that are specifically recognized by the cell can exploit the cell's own transport mechanisms to improve selective metal uptake
Remote Entanglement between a Single Atom and a Bose-Einstein Condensate
Entanglement between stationary systems at remote locations is a key resource
for quantum networks. We report on the experimental generation of remote
entanglement between a single atom inside an optical cavity and a Bose-Einstein
condensate (BEC). To produce this, a single photon is created in the
atom-cavity system, thereby generating atom-photon entanglement. The photon is
transported to the BEC and converted into a collective excitation in the BEC,
thus establishing matter-matter entanglement. After a variable delay, this
entanglement is converted into photon-photon entanglement. The matter-matter
entanglement lifetime of 100 s exceeds the photon duration by two orders
of magnitude. The total fidelity of all concatenated operations is 95%. This
hybrid system opens up promising perspectives in the field of quantum
information
Photon-Photon Entanglement with a Single Trapped Atom
An experiment is performed where a single rubidium atom trapped within a
high-finesse optical cavity emits two independently triggered entangled
photons. The entanglement is mediated by the atom and is characterized both by
a Bell inequality violation of S=2.5, as well as full quantum-state tomography,
resulting in a fidelity exceeding F=90%. The combination of cavity-QED and
trapped atom techniques makes our protocol inherently deterministic - an
essential step for the generation of scalable entanglement between the nodes of
a distributed quantum network.Comment: 5 pages, 4 figure
Shaping the Phase of a Single Photon
While the phase of a coherent light field can be precisely known, the phase
of the individual photons that create this field, considered individually,
cannot. Phase changes within single-photon wave packets, however, have
observable effects. In fact, actively controlling the phase of individual
photons has been identified as a powerful resource for quantum communication
protocols. Here we demonstrate the arbitrary phase control of a single photon.
The phase modulation is applied without affecting the photon's amplitude
profile and is verified via a two-photon quantum interference measurement,
which can result in the fermionic spatial behaviour of photon pairs. Combined
with previously demonstrated control of a single photon's amplitude, frequency,
and polarisation, the fully deterministic phase shaping presented here allows
for the complete control of single-photon wave packets.Comment: 4 pages, 4 figure
Isocyanide insertion into Au-H bonds: first gold iminoformyl complexes
Isocyanides insert into gold(III)-hydrogen bonds to give the first examples of gold iminoformyl complexes. The reaction is initiated by catalytic amounts of radicals; DFT calculations indicate that this is an equilibrium reaction driven forward by isocyanide in sufficient excess to trap the Au(II) intermediate
Probing domain walls in cylindrical magnetic nanowires with electron holography
3 pages, 2 figuresInternational audienceWe probe magnetic domain walls in cylindrical soft magnetic nanowires using electron holography. We detail the modelling of expected contrast for both transverse and Bloch point domain walls and provide comparison with experimental observations performed on NiCo nanowires, involving also both magnetic and electrostatic contribution to the electron holography map. This allows the fast determination of the domain wall type without the need for uneasy and time-consuming experimental removal of the electrostatic contribution. Finally, we describe and implement a new efficient algorithm for calculating the magnetic contrast
- …