106 research outputs found

    Cone beam CT evaluation of the presence of anatomic accessory canals in the jaws

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    Objectives: To assess the prevalence, location and anatomical course of accessory canals of the jaws using cone beam CT. Methods: A retrospective analysis of 4200 successive cone beam CT scans, for patients of both genders and ages ranging from 7 to 88 years, was performed. They were exposed at the School of Dentistry, University of Michigan, Ann Arbor, MI. After applying the exclusion criteria (the presence of severe ridge resorption, pre-existing implants, a previously reported history of craniofacial malformations or syndromes, a previous history of trauma or surgery, inadequate image quality and subsequent scans from the same individuals), 4051 scans were ultimately included in this study. Results: Of the 4051 scans (2306 females and 1745 males) that qualified for inclusion in this study, accessory canals were identified in 1737 cases (42.9%; 1004 females and 733 males). 532 scans were in the maxilla (13.1%; 296 females and 236 males) and 1205 in the mandible (29.8%; 708 females and 497 males). Conclusions: A network of accessory canals bringing into communication the inner and outer cortical plates of the jaws was identified. In light of these findings, clinicians should carefully assess for the presence of accessory canals prior to any surgical intervention to decrease the risk for complications

    Preliminary soil survey report for the Beni Magdoul and El Hammami areas

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    March 1979.CER78-79 EVR72.Includes bibliographical references.Prepared under support of United States Agency for International Development, Contract AID/NE-C-1351

    Beyond the pandemic : COVID-19 pandemic changed the face of life

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    Funding Information: This work was supported by the Swedish Research Council Vetenskapsr?det (VR grant 2016?05885). Funding Information: Acknowledgments: H.R. El-Seedi is very grateful to the Swedish Research links grant VR 2016– 05885 and the Department of Molecular Biosciences, Wenner-Grens Institute, Stockholm University, Sweden, for the financial support. Publisher Copyright: © 2021 by the au-thors. Licensee MDPI, Basel, Switzerland.The COVID-19 pandemic is a serious challenge for societies around the globe as entire populations have fallen victim to the infectious spread and have taken up social distancing. In many countries, people have had to self-isolate and to be confined to their homes for several weeks to months to prevent the spread of the virus. Social distancing measures have had both negative and positive impacts on various aspects of economies, lifestyles, education, transportation, food supply, health, social life, and mental wellbeing. On other hands, due to reduced population movements and the decline in human activities, gas emissions decreased and the ozone layer improved; this had a positive impact on Earth’s weather and environment. Overall, the COVID-19 pandemic has negative effects on human activities and positive impacts on nature. This study discusses the impact of the COVID-19 pandemic on different life aspects including the economy, social life, health, education, and the environment.publishersversionPeer reviewe

    Excess Lifetime Cancer Risk Associated with Granite Bearing Radioactive Minerals and Valuable Metals, Monqul Area, North Eastern Desert, Egypt

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    The present work is concerned with assessing the cancer risk contributed by the studied granite types including valuable metals, such as Cu, Au, and Ba mineralization, as well as radioactive-bearing mineralization, such as monazite and zircon, in south Monqul at Wadi Makhrag El Ebel, north Eastern Desert, Egypt. The mineralization analyses illustrated that copper mineralization containing chrysocolla and tenorite minerals were restricted to the alteration zone, especially (argillic, phyllic, and propylitic) in monzogranite. However, barite veinlets had an ENE–WSW trend, while gold mineralization was confined to quartz veins having NE–SW trends. Monazite and zircon are radioactive-bearing minerals recorded in monzogranite causing high radioactive zones in south Monqul. The radionuclide activity concentrations were detected in the studied monzogranites. The mean values of AU (103 ± 91 Bq kg−1), ATh (78 ± 19 Bq kg−1), and AK (1484 ± 334 Bq kg−1) in the monzogranite samples were higher than the recommended worldwide average. The change in radioactive-transporting minerals found inside granite faults caused the high amounts of radioactivity seen in the samples. Due to the monzogranites being applied in building materials, the radiological hazards were assessed by calculating risk indices such as annual effective dose (AED) and excess lifetime cancer risk (ELCR). The acceptable limit for the ELCR readings was surpassed. As a result, the investigated monzogranite samples are not suitable for use in infrastructure materials. © 2022 by the authors. Licensee MDPI, Basel, Switzerland

    Resonance Raman spectrum of triiodide complex formed in the reaction of iodine with 1,4,8, 11-tetraazacyclotetradecane

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    73-74The resonance Raman spectrum of the solid complex formed in the reaction of 1,4,8,11-tetraazacyclotetradecane (TACTD) with iodine exhibits characteristic bands of the triiodide ion, (I) at 147, 108 and 85 cm-1 assignable to vas(I- I), vs(I - I) and δ(I) modes, respectively. The formed complex is best described as [(TACTD)]+. I.</strong

    Automated Risk Control in Medical Imaging Equipment Management Using Cloud Application

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    Medical imaging equipment (MIE) is the baseline of providing patient diagnosis in healthcare facilities. However, that type of equipment poses high risk for patients, operators, and environment in terms of technology and application. Considering risk management in MIE management is rarely covered in literature. The study proposes a methodology that controls risks associated with MIE management. The methodology is based on proposing a set of key performance indicators (KPIs) that lead to identify a set of undesired events (UDEs), and through a risk matrix, a risk level is evaluated. By using cloud computing software, risks could be controlled to be manageable. The methodology was verified by using a data set of 204 pieces of MIE along 104 hospitals, which belong to Egyptian Ministry of Health. Results point to appropriateness of proposed KPIs and UDEs in risk evaluation and control. Thus, the study reveals that optimizing risks taking into account the costs has an impact on risk control of MIE management

    On the transition from static to dynamic boundary friction of lubricated PEEK for a spreading adhesive contact by macroscopic oscillatory tribometry

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    The tribology of lubricated poly(ether ether ketone) (PEEK)steel tribosystems was investigated in the static and boundary friction regime. Pentaerythrite ester and trimellitic acid ester were used as lubricants. The lubricants differed in their molecular structure but showed only minor differences in their rheological and cohesive energetic properties. In order to investigate the effect of the lubricants on static and dynamic friction, macroscopic oscillatory tribometry experiments and gliding experiments were carried out. The surface and interfacial energies of PEEK, lubricant, and steel, which can be used to determine e.g. the spreading tendency of the lubricant, were employed to explain the tribological characteristics of the system. The gliding experiments exhibited a velocity dependence of the coefficient of friction which indicates a rate-and-state type of friction. Trimellitic acid ester resulted in the lowest static and dynamic friction values due to its high tendency to spread. A different static friction behavior was found for pentaerythrite ester, which indicates a possible lubricant-induced mobilization of the polymer surface chains. This finding was supported by an increased interaction energy measured by contact angle measurements. The macroscopic oscillatory tribometry was shown to be a unique and precise method to investigate the transition from static to dynamic friction and to quantify macroscopic adhesive friction. Both types of experiments used a polished steel surface as a frictional partner, which favors the adhesive component of friction. However, the results for the lubricated contacts of polished steel surfaces in the boundary lubrication regime can give some insight into effects of the polymer transfer to rough steel surfaces in the mixed lubrication regime

    The transition from static to dynamic boundary friction of a lubricated spreading and a non-spreading adhesive contact by macroscopic oscillatory tribometry

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    Lubricated poly(ether ether ketone) (PEEK) and polyamide (PA46)steel tribosystems were investigated. They show a complex but systematic transition behavior from static to boundary friction, to dynamic friction or to mixed-lubrication. Nonstandard macroscopic oscillatory tribometry as well as gliding experiments were carried out. A previous study showed that the surface and interfacial energies of PEEK, lubricant and steel can indicate trends in the tribological behavior. In the current study, these findings are confirmed for PA46 and a wider range of lubricants. It was shown that a reversal of the order of the work of spreading of two lubricants by switching from PEEK to PA46 as polymer component in the tribological system also resulted in a reversal of the coefficient of friction (COF) a t low gliding velocities for these systems. The adhesion threshold of PA46 with the non-spreading lubricants water, glycerine, a waterglycerine mixture, ethylene glycol and poly-1-decene decreased with increasing solving tendency of the lubricants in contrast to the previous results for spreading lubricants for PEEK. Furthermore, the onset of forced wetting was studied for lubricants with different surface and interfacial energies and viscosities η. In general, a 1/η dependency was observed for the velocity which marks the onset of forced wetting. This agrees with theoretical models

    Towards an advanced mechanism to benefit from information systems in issuance of building permits

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    Issuing building permits process in Egypt faces many problems and difficulties. These difficulties are a result of many causes which maybe lack of experience in examining documents, the municipal personnel are not suitable to the tasks assigned to them, multiplicity of agencies taking approval on building permits, lack of databases and using traditional methods of accomplishing the work. In order to overcome most of these difficulties, the local government should utilize the new technologies because it has many capabilities and advantages. Geographic information system is a powerful technology that can support the municipalities in implementing their duties. Many municipalities today are using this powerful technology to improve the quality of decision-making, facilitate information sharing among officials and with the public, making municipal information and transactions easily accessible via the internet and make dramatic change in public presentations, reports and municipal web sites. In order to implement and manage the GIS system, some steps must be done to insure the success of the information system. The key factor in developing management strategies for the introduction, implementation, integration, and operation of GIS in any organization is to determine the appropriate role of GIS in the organization and to understand the implications of that role. This paper will discuss and demonstrate the importance of urban development control, the difficulties facing the process of issuing building permits, the importance of GIS in issuing permits and finally importance of developing strategies for the success of implementing and managing GIS in the organization
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