INTRODUCTION Debris buildup on the bracket-wire interface can influence friction. Cleansing brackets with air-powder polishing can affect this process. OBJECTIVE The aim of this study was to evaluate the frictional force and amount of debris remaining on orthodontic brackets subjected to prophylaxis with air-powder polishing. METHODS Frictional force and debris buildup on the surface of 28 ...

We present a geometric buildup algorithm for solving the sensor network localization problem with either accurate or noisy distance data. The algorithm determines the locations of the sensors, one at a time, by using the distances between the determined sensors and the undetermined ones. Each time, only a small system of distance equations needs to be solved and therefore, in an ideal case when...

Oxidative stress, caused by free radicals in the body, can have a damaging effect on the brain.12 The brain is particularly vulnerable to oxidative damage because of its high use of oxygen relative to its size and few antioxidant defense systems, among other factors.12 Oxidative damage can affect enzymatic activities in many proteins including glutamine synthetase, which converts glutamate to g...

Specimen charging may be one of the most significant factors that contribute to the high variability and generally low quality of images in cryo-electron microscopy. Understanding the nature of specimen charging can help in devising methods to reduce or even avoid its effects and thus improve the rate of data collection as well as the quality of the data. We describe a series of experiments tha...

Coronary artery disease is a narrowing of the small blood vessels that supply the heart. It is caused by plaque buildup in the vessel walls and can result in serious complications such as angina, damaged heart muscle, and death. Because of its prevalence, timely and accurate diagnosis of coronary artery disease is crucial. Different noninvasive imaging modalities are compared with factors such ...

Photon ambient dose equivalent buildup factors were calculated for point and plaque isotropic cobalt-60 and cesium-137 radioactive sources irradiating a finite slab shield materials of ordinary concrete, barite concrete, lead, lead glass and water using MCNP5 code. Studied shield thickness ranged from 1 to 15 mean free paths (mfp). A variance reduction technique available in the code was used t...

Introduction: Small field dosimetry is challenging for radiotherapy dosimetry. measurement of the output factor in the air and water (Sc, Scp) is one of the input parameters for commissioning of treatment planning systems and beam modeling. The aims of this study are to measured Sc,Scp for small fields with EBT2 and Ion chamber and design a appropriate mini-phantom for small fi...

Megacities and other major population centers represent large, concentrated sources of anthropogenic pollutants to the atmosphere, with consequences for both local air quality and for regional and global atmospheric chemistry. The tradeoffs between the regional buildup of pollutants near their sources versus long-range export depend on meteorological characteristics which vary as a function of ...