779 research outputs found
One-year clinical results of restorations using a novel self-adhesive resin-based bulk-fill restorative.
This prospective study assessed the dual-curing self-adhesive bulk-fill restorative Surefil one. The restorations were placed and reviewed by dental practitioners who are members of a practice-based research network in the United States. Seven practitioners filled 60 cavities (20 class I, 19 class II and 21 class V) in 41 patients with Surefil one without adhesive, according to the manufacturer's instructions. The restorations were evaluated using modified USPHS criteria at baseline, 3 months, and 1 year. Patients were also contacted to report postoperative hypersensitivity one to four weeks after placement. The only patient that showed moderate hypersensitivity after 1 year had previously reported symptoms that were unlikely associated to the class I molar restoration. One class II restoration in a fractured maxillary molar was partially lost. The remaining restorations were found to be in clinically acceptable condition resulting in an annual failure rate of 2%. Color match showed the lowest number of acceptable scores (88%) revealing significant changes over time (P = 0.0002). No significant differences were found for the other criteria (P > 0.05). The novel self-adhesive bulk-fill restorative showed clinically acceptable results in stress-bearing class I and II as well as non-retentive class V cavities at 1-year recall
Superconductivity in Co-doped LaFeAsO
Here we report the synthesis and basic characterization of LaFe1-xCoxAsO for
several values of x. The parent phase LaFeAsO orders antiferromagnetically (TN
~ 145 K). Replacing Fe with Co is expected to both electron dope the system and
introduce disorder in the FeAs layer. For x = 0.05 antiferromagnetic order is
destroyed and superconductivity is observed at Tconset = 11.2 K. For x = 0.11
superconductivity is observed at Tc(onset) = 14.3 K, and for x = 0.15 Tc = 6.0
K. Superconductivity is not observed for x = 0.2 and 0.5, but for x = 1, the
material appears to be ferromagnetic (Tc ~ 56 K) as judged by magnetization
measurements. We conclude that Co is an effective dopant to induce
superconductivity. Somewhat surprisingly, the system appears to tolerate
considerable disorder in the FeAs planes.Comment: 19 pages, 9 figure
Effects of nematic fluctuations on the elastic properties of iron arsenide superconductors
We demonstrate that the changes in the elastic properties of the FeAs
systems, as seen in our resonant ultrasound spectroscopy data, can be naturally
understood in terms of fluctuations of emerging nematic degrees of freedom.
Both the softening of the lattice in the normal, tetragonal phase as well as
its hardening in the superconducting phase are consistently described by our
model. Our results confirm the view that structural order is induced by
magnetic fluctuations.Comment: revised version with changed title accepted for publication in PR
Electrical Control of 2D Magnetism in Bilayer CrI3
The challenge of controlling magnetism using electric fields raises
fundamental questions and addresses technological needs such as low-dissipation
magnetic memory. The recently reported two-dimensional (2D) magnets provide a
new system for studying this problem owing to their unique magnetic properties.
For instance, bilayer chromium triiodide (CrI3) behaves as a layered
antiferromagnet with a magnetic field-driven metamagnetic transition. Here, we
demonstrate electrostatic gate control of magnetism in CrI3 bilayers, probed by
magneto-optical Kerr effect (MOKE) microscopy. At fixed magnetic fields near
the metamagnetic transition, we realize voltage-controlled switching between
antiferromagnetic and ferromagnetic states. At zero magnetic field, we
demonstrate a time-reversal pair of layered antiferromagnetic states which
exhibit spin-layer locking, leading to a remarkable linear dependence of their
MOKE signals on gate voltage with opposite slopes. Our results pave the way for
exploring new magnetoelectric phenomena and van der Waals spintronics based on
2D materials.Comment: To appear in Nature Nanotechnolog
A marking of the cricothyroid membrane with extended neck returns to correct position after neck manipulation and repositioning
Background: Emergency front of neck airway access by anaesthetists carries a high failure rate and it is recommended to identify the cricothyroid membrane before induction of anaesthesia in patients with a predicted difficult airway. We have investigated whether a marking of the cricothyroid membrane done in the extended neck position remains correct after the patient's neck has been manipulated and subsequently repositioned METHODS: The subject was first placed in the extended head and neck position and had the cricothyroid membrane identified and marked with three methods, palpation, 'laryngeal handshake' and ultrasonography and the distance from the suprasternal notch to the cricothyroid membrane was measured. The subject then moved off the table and sat on a chair and subsequently returned to the extended neck position and examinations were repeated.
Results: Skin markings of all 11 subjects lay within the boundaries of the cricothyroid membrane when the subject was repositioned back to the extended neck position and the median difference between the two measurements of the distance from the suprasternal notch was 0 mm (range 0-2 mm).
Conclusion: The cricothyroid membrane can be identified and marked with the subject in the extended neck position. Then the patient's position can be changed as needed, for example to the 'sniffing' neck position for conventional intubation. If a front of neck airway access is required during subsequent airway management, the patient can be returned expediently to the extended-neck position, and the marking of the centre of the membrane will still be in the correct place
Image equalisation using an external brightness reference
After more than ten years in orbit at Mars, the coverage from the High
Resolution Stereo Camera (HRSC) on the European Space Agency’s Mars Express is
sufficient to begin constructing mosaic products on a global scale. We
describe our systematic processing procedure and, in particular, the technique
used to bring images affected by atmospheric dust into visual consistency with
the mosaic. We outline how the same method is used to produce a relative
colour mosaic which shows local colour differences. We demonstrate the results
and show that the techniques may also be applied to images from other orbital
cameras
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