Search results for "Cone"
showing 10 items of 772 documents
ChemInform Abstract: Asymmetrically Substituted Calix(4)arenes. A Two-Dimensional 1H NMR Study of a Tetraester Derivative in the cone-Conformation.
2010
El coneixement i l'ús de les aplicacions educatives dels estudiants universitaris d'Espanya i la República Txeca
2020
Technological evolution has led to many changes at both professional and academic levels. The inclusion of Information and Communication Technologies (ICT) has caused dizzying changes in the different contexts of life (educational, professional, social). More and more applications are being downloaded by users to their mobile devices, both for entertainment and training. For this reason, this study is based on the need to assess the knowledge and attitude of university students towards downloading existing educational applications. In this way, the use and frequency of these tools in the teaching-learning process of the students will be analyzed. In order to carry out this study, the quanti…
The double cone: a mechanical paradox or a geometrical constraint?
2011
In the framework of the Italian National Plan ‘Lauree Scientifiche’ (PLS) in collaboration with secondary schools, we have investigated the mechanical paradox of the double cone. We have calculated the geometric condition for obtaining an upward movement. Based on this result, we have built a mechanical model with a double cone made of aluminum and a couple of wooden rails.
Diagnosis and treatment of dens invaginatus with open apex in a young adult patient by using cone-beam computed tomography and operative microscope.
2021
BACKGROUND: Dens invaginatus is a developmental anomaly that can affect both deciduous and permanent dentition. The anomaly is caused by the invagination of the enamel organ into the dental papilla prior to the calcification of the dental tissues. The treatment option changes according to the classification, from the simple filling of the invaginated enamel area to root canal treatment with or without retrograde surgery, intentional re-implantation, or the extraction of the affected tooth. CASE REPORT: In this study we report a case of a maxillary lateral incisor invaginatus in a young adult patient. The periapical endoral X-ray showed the presence of a periapical radiolucency in tooth 22, …
Effects of minute misregistrations of prefabricated markers for image-guided dental implant surgery: an analytical evaluation
2012
Objectives The goal of the present study was to develop a theoretical analysis of errors in implant position, which can occur owing to minute registration errors of a reference marker in a cone beam computed tomography volume when inserting an implant with a surgical stent. Material and methods A virtual dental-arch model was created using anatomic data derived from the literature. Basic trigonometry was used to compute effects of defined minute registration errors of only voxel size. The errors occurring at the implant's neck and apex both in horizontal as in vertical direction were computed for mean ±95%-confidence intervals of jaw width and length and typical implant lengths (8, 10 and 1…
Validity and reliability of the Turkish version of the orthognathic quality of life questionnaire in patients with dentofacial deformity
2021
Due to the lack of a specific quality of life (QoL) survey on dentofacial deformities (DFD) for Turkish speakers, the present research aimed to perform a translation of the English version of the Orthognathic Quality of Life Questionnaire (OQLQ) into Turkish (the OQLQ-TR) and provide cultural adaptation to the Turkish population. The process of this cross-cultural adaptation followed the six stages given in the guidelines that were proposed by Beaton et al. (2000), which comprised the following: 1) performing the initial translation, 2) synthesizing the translation, 3) performing the back translation, 4) presenting it to the expert committee, and 5) testing the prefinal version. Throughout …
Zum metabolismus von dialkyldithiocarbamaten
1974
Abstract Metabolism dialkyldithiocarbamates. I. Determination of amines using a reaction with isocyanates followed by gas chromatographic identification of the urea derivatives formed. N,N′-Di- and N,N′,N′-trisubstituted areas, formed by the reaction of amines with isocyanates, e.g. tert. -butyl isocyanate or 3-trifluoromethylphenyl isocyanate, are useful derivatives for the gas chromatographic analysis of primary and secondary amines. The separation is carried out at temperatures between 70 and 130° on liquid phases such as silicone OV-101 and silicone OV-17. With nitrogen and electron capture detectors the detection limit is 10 10 g. Trace analysis of simple primary and secondary amines i…
Direct synthesis of C3-mono-functionalized oxindoles from N-unprotected 2-oxindole and their antileishmanial activity.
2014
A novel approach for the synthesis of unprecedented C3-mono-functionalized indolin-2-ones is reported, starting from 2-oxindole and chalcones. The reactions proceed regioselectively under mild conditions, without di- and tri-alkylated side products. The new compounds have been evaluated in vitro for their antiproliferative effects against the protozoan Leishmania infantum. Interestingly, they appear able to kill L. infantum promastigotes and amastigotes, without significant cytotoxic effects.
Tertiary maars of the Hocheifel Volcanic Field, Germany
2008
In the Hocheifel only three maars are known. The Eckfeld Maar, filled with Eocene lacustrine sediments, is located at the southern boundary of the volcanic field, where the Tertiary peneplain has been eroded only slightly. The ages of the Jungferweiher Maar in the southeast and the Dottingen Maar in the northeast of the Tertiary Hocheifel Volcanic Field (THVF) are unknown and their timing within the THVF is uncertain. In contrast to the surrounding area, the central part of the THVF is deeply eroded. Here, six large diatremes (>600 m) were identified in the area of Kelberg with one exception. So far, no relics of crater sediments have been found within the large diatremes. They probably rep…
Structural investigation of four-centre photopolymerisation of bis-phthalamic bis-chalcone derivative in the crystalline state
1997
By combining the results obtained from an electron diffraction tilting series with solid state NMR and powder X-ray diffraction, it was possible to determine the unit cell parameters and space group of BPABC crystals grown from DMAA solution both before and after irradiation. Subsequently semi-empirical quantum mechanical and packing energy calculations led to a model structure which agreed well with all the electron diffraction data and thus provided insight into the cross-linking mechanism. © 1997 John Wiley & Sons Ltd.