Search results for "Radiation"

Diagnosis and Planning in Immediate Loading: Implant Selection

2019

Despite the increasing patients’ desire for immediate prosthetic loading of implants, several factors must be taken into account before pursuing the immediate loading (IL) protocol. In general, the number, size, characterization, and distribution of implants should be based on the implant-prosthodontic plan, arch form, and available bone quality and quantity, regardless of the loading protocol. However, implant selection in IL represents one of the most important clinical challenges due to the primary stability requirement.

Ultraviolet radiation protection by a beach umbrella.

2010

A beach umbrella intercepts all direct UV irradiance, but only part of the diffuse component. Using a simple sky view factor model, we have determined the fraction of the hemispheric diffuse irradiance that is not intercepted by the umbrella. Assuming a sensor at the surface and close to the center of the umbrella, isotropic diffuse irradiance and for an umbrella of 80 cm radius and 100 cm high, our results show that approximately 34% of the incident horizontal irradiance is not intercepted by the umbrella. These results agree with irradiance measurements conducted with and without the umbrella. The model is next extended to examine receipt of UV radiation by a human figure in a vertical po…

Channel Modeling and System Concepts for Future Terahertz Communications: Getting Ready for Advances Beyond 5G

2020

Future terahertz (THz) communications will utilize the frequency spectrum around 300 GHz. This technology provides a promising solution for future high-data-rate communications due to the high available bandwidth. However, the unfavorable channel characteristics are a major barrier for the realization of THz communications. To address the challenges caused by the unfavorable propagation conditions, the world?s first THz communication standard includes a channel-modeling document (CMD).

Konfokale Laser-Scanning-Mikroskopie (CLSM): Histotomographie veränderter Zahnhartgewebe bei pathologischer Mundhöhlenökologie

1997

There is no consensus regarding the aetiology of radiation-induced caries. Lesion formation is assumed to originate either from direct radiogenic damage of the hard tissue or from the indirect effects correlated with radioxerostomia. A comparative study is presented of sound teeth (group 1), teeth with documented radiation caries (group 2), teeth after in situ radiation (group 3): 60 Gy, fractionated) and teeth after in vitro radiation (group 4: 500-2500 Gy). Radiations were carried out with a 60Co source. The dentoenamel junction was studied with confocal laser scanning microscopy (CLSM). Axial sections of the teeth were used either fresh or embedded in Technovit (sawing-grinding technique…

WE-C-108-08: Organ Doses in a Male Phantom Undergoing High-Dose-Rate Brachytherapy Applied to the Prostate

2013

Purpose: The aim of this study was to obtain equivalent doses to radiosensitive organs when applying high‐dose‐rate (HDR) brachytherapy to the prostate using60 Co or 192 Ir sources, and in comparison to external‐beam radiotherapy (EBRT) modalities. Methods: Monte Carlo simulations in Geant4 were performed using a voxelized adult reference man described in Publication 110 by the International Commission on Radiological Protection (ICRP). Point sources of 60Co or 192Ir with photon energy spectra corresponding to those exiting their capsules were placed in the center of the prostate. Equivalent doses per therapeutic absorbed dose to the prostate were obtained in several radiosensitive organs. …

Neue Erkenntnisse zur Ätiologie der sogenannten Strahlenkaries

1997

Fragestellung Die Atiologie der Strahlenkaries wird trotz vieler Untersuchungen kontrovers diskutiert: Die These einer direkten radiogenen Lasion des Zahnhartgewebes steht der einer indirekten Pathogenese uber die Radioxerostomie gegenuber.

EP-1167: Dose distributions in radiotherapy of patients with titanium and resorbable implants

2013

Sepsis in head and neck cancer patients treated with chemotherapy and radiation: literature review and consensus

2015

Abstract: The reporting of infection/sepsis in chemo/radiation-treated head and neck cancer patients is sparse and the problem is underestimated. A multidisciplinary group of head and neck cancer specialists from Italy met with the aim of reaching a consensus on a clinical definition and management of infections and sepsis. The Delphi appropriateness method was used for this consensus. External expert reviewers then evaluated the conclusions carefully according to their area of expertise. The paper contains seven clusters of statements about the clinical definition and management of infections and sepsis in head and neck cancer patients, which had a consensus. Furthermore, it offers a revie…

First Measurement of the $Q^2$ Dependence of the Beam-Normal Single Spin Asymmetry for Elastic Scattering off Carbon

2018

We report on the first Q^{2}-dependent measurement of the beam-normal single spin asymmetry A_{n} in the elastic scattering of 570 MeV vertically polarized electrons off ^{12}C. We cover the Q^{2} range between 0.02 and 0.05  GeV^{2}/c^{2} and determine A_{n} at four different Q^{2} values. The experimental results are compared to a theoretical calculation that relates A_{n} to the imaginary part of the two-photon exchange amplitude. The result emphasizes that the Q^{2} behavior of A_{n} given by the ratio of the Compton to charge form factors cannot be treated independently of the target nucleus.

Airy-function approach to binary black hole merger waveforms: The fold-caustic diffraction model

2022

From numerical simulations of the Einstein equations, and also from gravitational wave observations, the gravitational wave signal from a binary black hole merger is seen to be simple and to possess certain universal features. The simplicity is somewhat surprising given that non-linearities of general relativity are thought to play an important role at the merger. The universal features include an increasing amplitude as we approach the merger, where transition from an oscillatory to a damped regime occurs in a pattern apparently oblivious to the initial conditions. We propose an Airy-function pattern to model the binary black hole (BBH) merger waveform, focusing on accounting for its simpl…