3,956 research outputs found
The influence of a new clinical motion for endodontic instruments on the incidence of postoperative pain
Previous studies showed that motor motions play an important role in determining apical extrusion of debris. Therefore a new clinical motion (MIMERACI) has been proposed. The basic idea is to progress slowly (1mm advancement), and after each 1mm, to remove the instrument from the canal, clean flutes and irrigate. The aim of the study was to prove whether the clinical use of MIMERACI technique would influence or not postoperative pain.MATERIALS AND METHODS:
100 teeth requesting endodontic treatment were selected for the study and divided into two similar groups based on anatomy, pre-operative symptoms and vitality, presence or absence of periapical lesion. All teeth were shaped, cleaned and obturated by the same operator, using the same NiTi instruments. The only difference between the two groups was the instrumentation technique: tradional (group A) vs MIMERACI (group B). Assessment of postoperative pain was performed 3 days after treatment. Presence, absence and degree of pain were recorded with a visual analogue scale (VAS), validated in previous studies. Collected data statistically analyzed using one-way ANOVA post hoc Tukey test.
RESULTS:
For VAS pain scores MIMERACI technique showed significantly better results than group A (p=0,031). Overall, both incidence and intensity of symptoms were significantly lower. Flare ups occurred in 3 patients, but none treated with the MIMERACI Technique.
CONCLUSIONS:
Since extruded debris can elicit more postoperative pain, results obtained by using MIMERACI technique are probably due to many factors: better mechanical removal and less production of debris and more efficient irrigation during instrumentation
Quasideterministic generation of maximally entangled states of two mesoscopic atomic ensembles by adiabatic quantum feedback
We introduce an efficient, quasideterministic scheme to generate maximally
entangled states of two atomic ensembles. The scheme is based on quantum
nondemolition measurements of total atomic populations and on adiabatic quantum
feedback conditioned by the measurements outputs. The high efficiency of the
scheme is tested and confirmed numerically for ideal photodetection as well as
in the presence of losses.Comment: 7 pages, 6 figures, title changed, revised version published on Phys.
Rev
Gut microbiota related to Giardia duodenalis, Entamoeba spp. and Blastocystis hominis infections in humans from CĂ´te d'Ivoire.
INTRODUCTION:
Literature data provide little information about protozoa infections and gut microbiota compositional shifts in humans. This preliminary study aimed to describe the fecal bacterial community composition of people from CĂ´te d'Ivoire harboring Giardia duodenalis, Entamoeba spp., and Blastocystis hominis, in trying to discover possible alterations in their fecal microbiota structure related to the presence of such parasites.
METHODOLOGY:
Twenty fecal samples were collected from people inhabiting three different localities of CĂ´te d'Ivoire for copromicroscopic analysis and molecular identification of G. duodenalis, Entamoeba spp., and B. hominis. Temporal temperature gradient gel electrophoresis (TTGE) was used to obtain a fingerprint of the overall bacterial community; quantitative polymerase chain reaction (qPCR) was used to define the relative abundances of selected bacterial species/group, and multivariate statistical analyses were employed to correlate all data.
RESULTS:
Cluster analysis revealed a significant separation of TTGE profiles into four clusters (p < 0.0001), with a marked difference for G. duodenalis-positive samples in relation to the others (p = 5.4Ă—10-6). Interestingly, qPCR data showed how G. duodenalis-positive samples were related to a dysbiotic condition that favors potentially harmful species (such as Escherichia coli), while Entamoeba spp./B. hominis-positive subjects were linked to a eubiotic condition, as shown by a significantly higher Faecalibacterium prausnitzii-Escherichia coli ratio.
CONCLUSIONS:
This preliminary investigation demonstrates a differential fecal microbiota structure in subjects infected with G. duodenalis or Entamoeba spp./B. hominis, paving the way for using further next-generation DNA technologies to better understand host-parasite-bacteria interactions, aimed at identifying potential indicators of microbiota changes
Phase-change chalcogenide glass metamaterial
Combining metamaterials with functional media brings a new dimension to their
performance. Here we demonstrate substantial resonance frequency tuning in a
photonic metamaterial hybridized with an electrically/optically switchable
chalcogenide glass. The transition between amorphous and crystalline forms
brings about a 10% shift in the near-infrared resonance wavelength of an
asymmetric split-ring array, providing transmission modulation functionality
with a contrast ratio of 4:1 in a device of sub-wavelength thickness.Comment: 3 pages, 3 figure
A bacterial ratchet motor
Self-propelling bacteria are a dream of nano-technology. These unicellular
organisms are not just capable of living and reproducing, but they can swim
very efficiently, sense the environment and look for food, all packaged in a
body measuring a few microns. Before such perfect machines could be
artificially assembled, researchers are beginning to explore new ways to
harness bacteria as propelling units for micro-devices. Proposed strategies
require the careful task of aligning and binding bacterial cells on synthetic
surfaces in order to have them work cooperatively. Here we show that asymmetric
micro-gears can spontaneously rotate when immersed in an active bacterial bath.
The propulsion mechanism is provided by the self assembly of motile Escherichia
coli cells along the saw-toothed boundaries of a nano-fabricated rotor. Our
results highlight the technological implications of active matter's ability to
overcome the restrictions imposed by the second law of thermodynamics on
equilibrium passive fluids.Comment: 4 pages, 3 figure
Evolution of Large Scale Curvature Fluctuations During the Perturbative Decay of the Inflaton
We study the evolution of cosmological fluctuations during and after
inflation driven by a scalar field coupled to a perfect fluid through afriction
term. During the slow-roll regime for the scalar field, the perfect fluid is
also frozen and isocurvature perturbations are generated. After the end of
inflation, during the decay of the inflaton, we find that a change in the
observationally relevant large scale curvature fluctuations is possible.Comment: 9 pages, 2 figures; v2: version published in PR
Plio-Pleistocene geological evolution of the northern Sicily continental margin (southern Tyrrhenian Sea): new insights from high-resolution, multi-electrode sparker profiles
High-resolution seismic profiles were acquired in the north Sicily offshore region with an innovative, multi-tip sparker array which lacks ringing and has a base frequency around 600 Hz. The new data, combined
with published data, suggest that intra-slope and extensional basins formed as a consequence of the late
Miocene (?)–early Pliocene shortening and thrusting,
and the middle (?)–late Pliocene continental rifting affecting the internal side of the Sicilian-Maghrebian chain. Early (?) Pleistocene to Holocene high-amplitude
and high-frequency sea-level changes resulted in repeated
sub-aerial exposure and flooding of the shelf, and the deposition of cyclically arranged hemipelagic and shelf sediments. An uplift of the shelf could explain the non-preservation of the transgressive and of the lowstand wedge systems tracts in the oldest sequences
- …