introduction: preserving the apical root structure during cleaning and shaping of the canal has always been a challenge in endodontics particularly when the root canals are curved. the purpose of this in vitro study was to compare the apical transportation induced by the reciproc and biorace rotary systems in preparing the mesiobuccal root canal of the human maxillary molars. materials and meth...

Safety risk study on road transportation of hazardous chemicals is a reliable basis for the government to formulate transportation planning and preparing emergent schemes, but also is an important reference for safety risk managers to carry out dangerous chemicals safety risk managers. Based on the analysis of the transport safety risk of dangerous chemicals at home and abroad, this paper studi...

introduction: due to the importance of apical transportation during root canal preparation, the aim of the current study was to use cone-beam computed tomography (cbct) to assess the extent of apical transportation caused by protaper and mtwo files. methods and materials: forty extracted maxillary first molars with 19-22 mm length and 20-40 degrees of curvature were selected. the mesiobuccal ca...

Abstract This study aimed to develop a spatial database design on transportation safety system. Spatial databases is fundamental factor that very important in the utilization of GIS for transportation, so it good preparation databases. Preparation will be effective if tailored needs. Factors affecting different from one region another. affect system an area can influenced by infrastructure area...

In view of the pressing need to reduce negative environmental impact freight transportation we argue that it is essential take account organization system when considering how address various individual activities and parts system. To support a transition more sustainable this paper examines way in which different interact can scope for profound change. Taking loosely coupled systems (Weick, 19...

contrary to the past approaches, as the transportation speed and the number of vehicles have increased, nowadays, the major roads do not go through the cities and are laid out on the brink with a particular distance instead and linked with the city’s network through a set of connecting roads instead. construction of these connecting roads can have diverse effects on economic, social and cultura...