196 research outputs found
Zygomatic Implant Survival in 9 Ectodermal Dysplasia Patients with 3.5 to 7-year Follow Up
Ectodermal dysplasia syndrome is a complex group of genetic disorders identified by the abnormal development of the ectodermal structures. The aim of this retrospective clinical case series report was to evaluate the outcomes of the ectodermal dysplasia syndrome patients that underwent zygomatic implant surgery.
Materials and Methods: A total of 9 ectodermal dysplasia syndrome patients aged between 21 and 56 years (mean age 36.8) with severely atrophic maxilla were included in this study. All the patients were treated with a total of 19 zygomatic implants. The mean follow-up of the patients was 55 months (with a range of 44\u201384 months). The implant survival rate was evaluated as a primary outcome. The intra- and postoperative
complications were evaluated as additional criteria for success.
Results: The overall implant survival rate was 100% without any complications. Final or provisional prosthesis was delivered on the same day of surgery, which resulted in an improvement of the quality of life of the patients.
Conclusion: According to the results of this study, zygomatic surgery can be considered
as a viable and safe alternative to conventional treatment modalities for oral
rehabilitation of ectodermal dysplasia syndrome patients
Hemifacial microsomia: Case report and literature review
Hemifacial microsomia (HFM) is a sporadic congenital malformation of the craniofacial structures derived from the first and second branchial arches. The incidence of HFM has been reported to range from 1 in 3,0001 to 1 in 26,0002 live births, making HFM the second most common congenital malformation in the face after cleft lip and/or palate. An 11-year-old girl came at Galeazzi Institute (Milan) in January 2017. She presented left hemifacial microsomia with absence of the left ramus of mandible and the left temporomandibular joint (tmj), part of the zygomatic arch, hypoplasia of the lateral and inferior orbital bone and of the zygomatic bone. She also presented a medial canthal dystopia. She underwent to costochondral bone graft and calvaria bone graft for reconstruction of part of the mandible and the TMJ. An emi-Le Fort I, emi-Le Fort III, and sagittal segmental osteotomy of the right mandible were performed to improve the correct occlusion. Traditionally, the costochondral graft has been considered the gold standard for ramus-condyle reconstruction in the pediatric mandible when appropriate. Some studies cite growth unpredictability and ankylosis as concerns with rib. Further studies examining carefully the factors predicting graft growth, such as size of cartilage cap, surgical technique, and postoperative physiotherapy, are warranted
Electroactive chiral oligo- and polymer layers for electrochemical enantiorecognition
Electronically conducting polymer (ECP) and oligomer films are one of the most popular classes of artificial materials for electrode surface modification and nanostructured electroactive film preparation for use as active layers in advanced sensing electrochemical devices. They can act as both receptors and transducers on account of their electroactivity and easy derivatization in a virtually unlimited structure range, and typically have low cost and easy processability. The tailoring possibilities of ECP films also make them attractive selector candidates to achieve the superior level of molecular recognition represented by enantioselective electroanalysis, implying to discriminate between specular images of a chiral molecule . This superior recognition level requires to endow them with chirality and to employ them as enantiopure films, which can be made along different strategies, with different implications in terms of enantioselectivity, kind of transduction of the recognition event, specificity vs general applicability, preparation difficulty, robustness, etc. In this context an outstanding tool is provided by the \u201cinherent chirality\u201dstrategy
Enantiomer discrimination in absorption spectroscopy and in voltammetry: highlighting fascinating similarities and connections
Absorption spectroscopy and voltammetry, of known analogies and connections, share even more fascinating similarities and connections at a higher complexity level, when "upgrading" them with the ability to discriminate between enantiomers by chiral selector implementation. In both techniques either "molecular" selectors or "electromagnetic" ones (L- versus Rcircularly polarized light components for spectroscopy, ccversus b-spin electrons for voltammetry) can be considered; moreover, external magnetic field application can replace a truly chiral actor. A tentative schematization is provided. Analogies and connections also concern molecular features of the enantiodiscrimination actors. In both techniques outstanding performances are obtained with inherently chiral molecules, in which a conjugated backbone with tailored torsion is source of chirality as well as spectroscopic and electrochemical activity, in an attractive three-fold interconnection. Their outstanding effects can be justified by a combination of chemical and electromagnetic properties (excellent potential molecular spin filters), a fascinating challenge for future developments
Seismic analysis of the Roman Temple of Évora, Portugal
The Roman temple of Évora dates back to the 1st century AD and has undergone several changes throughout history, including various additions, which have been removed. Several archaeological studies have recently been carried out, but the structural safety of the temple is unknown. Of particular concern is the temple’s seismic resistance, as it is located in a region subjected to a moderate seismic hazard.
The main purpose of this paper is to ascertain the temple’s behaviour under seismic excitation through limit analysis and discrete element analysis. Both analysis techniques will use the assumption that the structure is composed of rigid blocks connected with dry joints. Geometric information has been derived from a recent laser scanning surveying, while calibration undertaken using in-situ results from GPR and dynamic identification tests. The main results are presented and discussed in detail as well as the need for possible repair works within the framework of the ICARSAH guidelines
Perturbation Theory for Metastable States of the Dirac Equation with Quadratic Vector Interaction
The spectral problem of the Dirac equation in an external quadratic vector
potential is considered using the methods of the perturbation theory. The
problem is singular and the perturbation series is asymptotic, so that the
methods for dealing with divergent series must be used. Among these, the
Distributional Borel Sum appears to be the most well suited tool to give
answers and to describe the spectral properties of the system. A detailed
investigation is made in one and in three space dimensions with a central
potential. We present numerical results for the Dirac equation in one space
dimension: these are obtained by determining the perturbation expansion and
using the Pad\'e approximants for calculating the distributional Borel
transform. A complete agreement is found with previous non-perturbative results
obtained by the numerical solution of the singular boundary value problem and
the determination of the density of the states from the continuous spectrum.Comment: 10 pages, 1 figur
Current oscillations in a metallic ring threaded by a time-dependent magnetic flux
We study a mesoscopic metallic ring threaded by a magnetic flux which varies
linearly in time PhiM(t)=Phi t with a formalism based in Baym-Kadanoff-Keldysh
non-equilibrium Green functions. We propose a method to calculate the Green
functions in real space and we consider an experimental setup to investigate
the dynamics of the ring by recourse to a transport experiment. This consists
in a single lead connecting the ring to a particle reservoir. We show that
different dynamical regimes are attained depending on the ratio hbar Phi/Phi0
W, being Phi0=h c/e and W, the bandwidth of the ring. For moderate lengths of
the ring, a stationary regime is achieved for hbar Phi/Phi0 >W. In the opposite
case with hbar Phi/Phi0 < W, the effect of Bloch oscillations driven by the
induced electric field manifests itself in the transport properties of the
system. In particular, we show that in this time-dependent regime a tunneling
current oscillating in time with a period tau=2piPhi0/Phi can be measured in
the lead. We also analyze the resistive effect introduced by inelastic
scattering due to the coupling to the external reservoir.Comment: 17 pages, 13 figure
One-Dimensional Discrete Stark Hamiltonian and Resonance Scattering by Impurities
A one-dimensional discrete Stark Hamiltonian with a continuous electric field
is constructed by extension theory methods. In absence of the impurities the
model is proved to be exactly solvable, the spectrum is shown to be simple,
continuous, filling the real axis; the eigenfunctions, the resolvent and the
spectral measure are constructed explicitly. For this (unperturbed) system the
resonance spectrum is shown to be empty. The model considering impurity in a
single node is also constructed using the operator extension theory methods.
The spectral analysis is performed and the dispersion equation for the
resolvent singularities is obtained. The resonance spectrum is shown to contain
infinite discrete set of resonances. One-to-one correspondence of the
constructed Hamiltonian to some Lee-Friedrichs model is established.Comment: 20 pages, Latex, no figure
A long-term perspective on deforestation rates in the Brazilian Amazon
Monitoring tropical forest cover is central to biodiversity preservation, terrestrial carbon stocks, essential ecosystem and climate
functions, and ultimately, sustainable economic development. The Amazon forest is the Earth’s largest rainforest, and despite
intensive studies on current deforestation rates, relatively little is known as to how these compare to historic (pre 1985) deforestation
rates. We quantified land cover change between 1975 and 2014 in the so-called Arc of Deforestation of the Brazilian Amazon,
covering the southern stretch of the Amazon forest and part of the Cerrado biome. We applied a consistent method that made use of
data from Landsat sensors: Multispectral Scanner (MSS), Thematic Mapper (TM), Enhanced Thematic Mapper Plus (ETM+) and
Operational Land Imager (OLI). We acquired suitable images from the US Geological Survey (USGS) for five epochs: 1975, 1990,
2000, 2010, and 2014. We then performed land cover analysis for each epoch using a systematic sample of 156 sites, each one
covering 10 km Ă— 10 km, located at the confluence point of integer degree latitudes and longitudes. An object-based classification of
the images was performed with five land cover classes: tree cover, tree cover mosaic, other wooded land, other land cover, and water.
The automatic classification results were corrected by visual interpretation, and, when available, by comparison with higher
resolution imagery. Our results show a decrease of forest cover of 24.2% in the last 40 years in the Brazilian Arc of Deforestation,
with an average yearly net forest cover change rate of -0.71% for the 39 years considered
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