Search results for "Root"
showing 10 items of 1237 documents
[The effect of instrumentation on original apical foramen shape using steel vs niti rotatory: computerized analysis]
2002
BACKGROUND. A fundamental requirement to obtain a correct endodontic preparation depends on the respect, during cleaning and shaping, of the original morphology of the apical foramen, (AF), so that the filling material will form a complete seal. METHODS. In our previous studies, in order to verify if this presumption was respected using rotary NiTi instruments with cutting tip, we instrumented extracted teeth characterised by a different degree of root curvatures. Using a standardized system to replace the sample, the original shape of the apical foramen of each tooth was recorded using a computerised technique and then compared to the shape after instrumentation. The data showed difference…
Ultrasound Effects after Post Space Preparation: An SEM Study
2006
The aim of this study was to evaluate the effect of ultrasonic treatment on occlusion of dentine tubules in root canal walls after post space preparation in endodontically treated teeth. Twenty-four premolars were instrumented and filled using warm vertical condensation; after post space preparation, they were divided into two groups. The control group was treated using the etching procedure. The experiment samples were treated with EDTA irrigation and ultrasound activation for 30 s before the etching procedure. The roots were divided and the canal walls were examined under SEM at 1000x magnification. The debris and open tubule marks were observed at 2, 6, and 10 mm levels using a three-ste…
Combination of measurements of the top-quark pair production cross section from the Tevatron Collider
2014
We combine six measurements of the inclusive top-quark pair (tt̄) production cross section (σtt̄) from data collected with the CDF and D0 detectors at the Fermilab Tevatron with proton-antiproton collisions at s=1.96TeV. The data correspond to integrated luminosities of up to 8.8fb-1. We obtain a value of σtt̄=7.60±0.41pb for a top-quark mass of mt=172.5GeV. The contributions to the uncertainty are 0.20 pb from statistical sources, 0.29 pb from systematic sources, and 0.21 pb from the uncertainty on the integrated luminosity. The result is in good agreement with the standard model expectation of 7.35-0.33+0.28pb at next-to-next-to-leading order and next-to-next-to leading logarithms in pert…
Combination of D0 measurements of the top quark mass
2017
We present a combination of measurements of the top quark mass by the D0 experiment in the lepton+jets and dilepton channels. We use all the data collected in Run I (1992--1996) at $\sqrt s=1.8$ TeV and Run II (2001--2011) at $\sqrt s=1.96$ TeV of the Tevatron $p \bar{p}$ collider, corresponding to integrated luminosities of 0.1 fb$^{-1}$ and 9.7 fb$^{-1}$, respectively. The combined result is: $m_t = 174.95 \pm0.40\,{\rm(stat)} \pm 0.64\,{\rm(syst)}\,{\rm{GeV}}=174.95 \pm 0.75 \, {\rm{GeV}}$.
The Arabidopsis Copper Transporter COPT1 Functions in Root Elongation and Pollen Development
2004
Copper plays a dual role in aerobic organisms, as both an essential and a potentially toxic element. To ensure copper availability while avoiding its toxic effects, organisms have developed complex homeostatic networks to control copper uptake, distribution, and utilization. In eukaryotes, including yeasts and mammals, high affinity copper uptake is mediated by the Ctr family of copper transporters. This work is the first report on the physiological function of copper transport in Arabidopsis thaliana. We have studied the expression pattern of COPT1 in transgenic plants expressing a reporter gene under the control of the COPT1 promoter. The reporter gene is highly expressed in embryos, tric…
Neuropeptides in Primary Afferent Neurons
1990
Traditionally, the primary sensory neurons, having their perikarya in the spinal or cranial sensory ganglia with processes directed towards the periphery and the central nervous system, have been regarded to function as receptive and afferent systems which reflexly activate central effector systems.1 This, however, does not apply to the small diameter primary afferents as suggested by the observation made about a century ago that antidromic stimulation of transected dorsal roots or sensory nerves caused vasodilatation and inflammatory signs in the skin.2,3 The novel concept which has been confirmed by many investigators ascribes to small diameter (particularly unmyelinated C) primary sensor…
Chionaeosides A–D, Triterpene Saponins from Paronychia chionaea
2007
Four new triterpenoid saponins, chionaeosides A-D (1-4) were isolated from the roots of Paronychia chionaea. On the basis of their spectroscopic data, the structures of the new saponins were established as 3-O-alpha-L-arabinopyranosylgypsogenic acid 28-O-beta-D-glucopyranosyl-(1--3)-beta-D-glucopyranosyl-(1--6)-beta-D-glucopyranoside (1), 3-O-alpha-L-arabinopyranosylgypsogenic acid 28-O-beta-D-glucopyranosyl-(1--6)-beta-D-glucopyranoside (2), 3-O-alpha-L-arabinopyranosylgypsogenic acid 28-O-beta-D-glucopyranoside (3), and 3-O-alpha-L-arabinopyranosylgypsogenic acid (4).
Triterpene Glycosides from the Roots of Astragalus flavescens
2007
Six new triterpene saponins, 3-O-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-xylopyranosyl-(1-->2)-beta-D-glucuronopyranosyl-21-epi-kudzusapogenol A (1), 3-O-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranosyl-(1-->2)-beta-D-glucuronopyranosyl-21-epi-kudzusapogenol A (2), 3-O-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-xylopyranosyl-(1-->2)-beta-D-glucuronopyranosyl-22-O-beta-D-glucopyranosyl-21-epi-kudzusapogenol A (3), 3-O-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranosyl-(1-->2)-beta-D-glucuronopyranosyl-22-O-beta-D-glucopyranosyl-21-epi-kudzusapogenol A (4), 3-O-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-xylopyranosyl-(1-->2)-beta-D-glucuronopyranosyl-22-O-alpha-L-arabinopyranosyl-21-epi-kudzus…
Push-out bond strength of different endodontic obturation material at three different sites : in-vitro study
2017
BACKGROUND The key to success of any root canal therapy is adequate obturation of the prepared root canal space. Root canal sealers are not dimensionally stable and might dissolve partially over a period of time. The objective of this in vitro study is to evaluate the push-out bond strength to intraradicular dentin of two endodontic obturation materials. MATERIAL AND METHODS Forty extracted single rooted permanent teeth were used. Canals orifice was explored, teeth were instrumented. The samples were divided into two groups each containing twenty specimens obturated with different obturation material (Group1 Epiphany/Resilon and Group 2 Gutta Percha/AH Plus).The obturation systems used in t…
Fracture resistance of roots filled with three different obturation techniques
2012
Objectives: The aim of this study was to compare in vitro root fracture resistance following root canal filling with AH 26 using lateral condensation, BeeFill, and Thermafil techniques. Study Design: Eighty extracted human mandibular premolars with similar dimensions were selected. In order to standardize the roots, measurements were taken in two separate regions of the teeth—at the cemento-enamel junction and 8 mm apically from the junction—buccolingual as well as mesiodistal for every tooth. Teeth were then randomly divided into five groups (n=16). With the exception of the non-prepared group (Group 1), instrumentation was done in all groups. In group 2, instrumentation but no filling was…