143 research outputs found
Measurements for restorative dentistry: shrinkage and conversion degree of bulk-fill composites
The paper deals with a measuring approach based on Raman Spectroscopy and micro-CT imaging for correlating the degree of conversion of bulk-fill composites to the contraction shrinkage and consequently to the internal gap formation in high c-factor dental cavities. The developed study was performed on extracted molars in which a first-class cavity was prepared. A micro-CT scan was performed before and after composite lightcuring to tridimensionally measure the interfacial gap between the composite material and the cavity walls. After the complete polymerization of the composite, each sample was sectioned vertically to expose the lateral surface of the restorative material. Raman Spectroscopy measurements were performed along the cross-section of the cavity filled with the restorative material, every 0.5 mm from the occlusal surface. The obtained results showed a minimal gap opening after light-curing and a degree of conversion which was not affected by the bulk-fill composite thickness. Thanks to the 3D rendering, it should be observed that gaps were mostly concentrated at the cavity floor and despite the reduction in the degree of conversion detected in the deeper portions of the restoration, a three-dimensional opening of an interfacial gap was not observed. Therefore, it is possible to assume the presence of a correlation between the degree of conversion and the volumetric interfacial gap could. Further studies are actually in progress to compare these preliminary results with those obtained on other dental composite materials
Working length transfer in the endodontic clinical practice: A comparative study
8The present paper evaluated the accuracy of two different methods for transferring working
length (WL) between manual endodontic instruments and nickel–titanium (NiTi) shaping files.
Thirty root canals of extracted permanent teeth were used. Root canals were divided according to
canal length (CL) and canal curvature (CC). The reference cusp and the root end were flattened to
provide reproducible and accurate measurements. During shaping, the WL measurements were
obtained with manual k-files (KF) and transferred to WaveOne (W1) NiTi reciprocating files using
the traditional method with the endodontic ruler (method I) and an alternative clinical procedure
based on the comparison of the instruments side by side from tip to shank (method II). For each file
and each tested method, two measures were taken by two examiners using Rhino (ver. 4.0, McNeel,
Seattle, WA, USA) software for a total of 360 (30 × 3 × 2 × 2) measures. Analysis of variance was
performed by taking the difference in length (Delta WL, DWL) between files used for the same canal.
The difference between methods I and II for WL transfer was found to be statistically significant
(df = 1; F = 71.52; p < 0.001). The DWL absolute values obtained with method II were found to be
closer to 0 mm (i.e., same length as corresponding KF) than those obtained with method I. Both CL
(df = 2; F = 1.27; p = 0.300) and CC (df = 1; F = 2.22; p = 0.149) did not significantly influence WL
measurements. With respect to WL transfer, method II seemed to better preserve the correct WL
transfer between instruments during the clinical endodontic procedures.openopenMario Alovisi; Mario Dioguardi; Massimo Carossa; Giuseppe Troiano; Maria Chiara Domini; Davide Salvatore Paolino; Giorgio Chiandussi; Elio BeruttiAlovisi, Mario; Dioguardi, Mario; Carossa, Massimo; Troiano, Giuseppe; Chiara Domini, Maria; Paolino, DAVIDE SALVATORE; Chiandussi, Giorgio; Berutti, Eli
Evaluation of the bactericidal activity of a hyaluronic acid-vehicled clarithromycin antibiotic mixture by confocal laser scanning microscopy
Confocal laser scanning microscopy (CLSM) was used to evaluate the antibacterial effect and depth of action of a novel clarithromycin-containing triple antibiotic mixture, which was proposed for root canal disinfection in dental pulp regeneration. A previous study reported that this mixture had no tooth discoloration effects in vitro. After infection with Enterococcus faecalis for 3 weeks, the dentinal tubules in the cylindrical root specimens were exposed to different antibiotic mixtures: ciprofloxacin, metronidazole and minocycline (3-MIX); ciprofloxacin, metronidazole and clarithromycin (3-MIXC) and ciprofloxacin and metronidazole (2-MIX). Each antibiotic formulation was mixed with macrogol (MG) or hyaluronic acid (HA) vehicles. CLSM and viability staining were used to quantitatively analyze the mean depth of the antibacterial effect and the proportions of dead and live bacteria inside the dentinal tubules. The 3-MIX and 3-MIXC demonstrated a similar depth of action. The mean proportion of dead bacteria was similar in the 3-MIX and 3-MIXC groups, and both were statistically higher than that of 2-MIX (p = 0.014). Each antibiotic mixture showed a higher bactericidal efficacy if conveyed with HA, compared to MG (3-MIX, p = 0.019; 3-MIXC, p = 0.013 and 2-MIX, p = 0.0125). The depth of action and the antibacterial efficacy of 3-MIXC seemed comparable with 3-MIX
Clonal hematopoiesis as a pitfall in germline variant interpretation in the context of Mendelian disorders
Clonal hematopoiesis because of somatic mutations in hematopoietic stem/progenitor cells is an age-related phenomenon and commonly observed when sequencing blood DNA in elderly individuals. Several genes that are implicated in clonal hematopoiesis are also associated with Mendelian disorders when mutated in the germline, potentially leading to variant misinterpretation. We performed a literature search to identify genes associated with age-related clonal hematopoiesis followed by an OMIM query to identify the subset of genes in which germline variants are associated with Mendelian disorders. We retrospectively screened for diagnostic cases in which the presence of age-related clonal hematopoiesis confounded exome sequencing data interpretation. We found 58 genes in which somatic mutations are implicated in clonal hematopoiesis, while germline variants in the same genes are associated with Mendelian (mostly neurodevelopmental) disorders. Using five selected cases of individuals with suspected monogenic disorders, we illustrate how clonal hematopoiesis in either variant databases or exome sequencing datasets poses a pitfall, potentially leading to variant misclassification and erroneous conclusions regarding gene-disease associations
Performance of the LHCb muon system with cosmic rays
The LHCb Muon system performance is presented using cosmic ray events
collected in 2009. These events allowed to test and optimize the detector
configuration before the LHC start. The space and time alignment and the
measurement of chamber efficiency, time resolution and cluster size are
described in detail. The results are in agreement with the expected detector
performance.Comment: Submitted to JINST and accepte
Performance of the LHCb muon system
The performance of the LHCb Muon system and its stability across the full
2010 data taking with LHC running at ps = 7 TeV energy is studied. The
optimization of the detector setting and the time calibration performed with
the first collisions delivered by LHC is described. Particle rates, measured
for the wide range of luminosities and beam operation conditions experienced
during the run, are compared with the values expected from simulation. The
space and time alignment of the detectors, chamber efficiency, time resolution
and cluster size are evaluated. The detector performance is found to be as
expected from specifications or better. Notably the overall efficiency is well
above the design requirementsComment: JINST_015P_1112 201
MAPEAMENTO DIGITAL DO SISTEMA AQÜÍFERO CÁRSTICO NO SÍTIO DE TRANQUEIRA REGIÃO METROPOLITANA DE CURITIBA, FASE ATUAL
Com este trabalho, apresenta-se o estágio atual do Projeto de Mapeamento
Digital do Sistema Aqüífero Cárstico - MAPSAC -, que se iniciou em
1996 com a participação de um Grupo Multidisciplinar. A finalidade
principal com o MAPSAC é explorar as informações e os dados
espacialmente referenciados para obter um entendimento do Sistema
Aqüífero localizado em Tranqueira, próximo a Curitiba.
Abstract
This paper describes the current stage of the project for digital mapping of
the Karst aquifer system - MAPKAS. This project started in 1996 and is
conducted by a interdisciplinary group. Its main objective is to explore
spatially referenced data in order to understanding the structure of the
aquifer system aiming at its future use without depleting it. The aquifer is
located at Tranqueira site, near Curitiba. It is scrutiny and is expected to
be used as one of the major sources of fresh water for the city
MAU2 and NIPBL variants impair the heterodimerization of the cohesin loader subunits and cause Cornelia de Lange syndrome
The NIPBL/MAU2 heterodimer loads cohesin onto chromatin. Mutations inNIPBLaccount for most cases ofthe rare developmental disorder Cornelia de Lange syndrome (CdLS). Here we report aMAU2 variant causing CdLS, a deletion of seven amino acids that impairs the interaction between MAU2 and the NIPBL N terminus.Investigating this interaction, we discovered that MAU2 and the NIPBL N terminus are largely dispensable fornormal cohesin and NIPBL function in cells with a NIPBL early truncating mutation. Despite a predicted fataloutcome of an out-of-frame single nucleotide duplication inNIPBL, engineered in two different cell lines,alternative translation initiation yields a form of NIPBL missing N-terminal residues. This form cannot interactwith MAU2, but binds DNA and mediates cohesin loading. Altogether, our work reveals that cohesin loading can occur independently of functional NIPBL/MAU2 complexes and highlights a novel mechanism protectiveagainst out-of-frame mutations that is potentially relevant for other genetic conditions
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